fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/percpu_counter.h>
  28 #include "hash.h"
  29 #include "tree-log.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "volumes.h"
  33 #include "raid56.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36 #include "free-space-tree.h"
  37 #include "math.h"
  38 #include "sysfs.h"
  39 #include "qgroup.h"
  40
  41 #undef SCRAMBLE_DELAYED_REFS
  42
  43 /*
  44  * control flags for do_chunk_alloc's force field
  45  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  46  * if we really need one.
  47  *
  48  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  49  * if we have very few chunks already allocated.  This is
  50  * used as part of the clustering code to help make sure
  51  * we have a good pool of storage to cluster in, without
  52  * filling the FS with empty chunks
  53  *
  54  * CHUNK_ALLOC_FORCE means it must try to allocate one
  55  *
  56  */
  57 enum {
  58         CHUNK_ALLOC_NO_FORCE = 0,
  59         CHUNK_ALLOC_LIMITED = 1,
  60         CHUNK_ALLOC_FORCE = 2,
  61 };
  62
  63 /*
  64  * Control how reservations are dealt with.
  65  *
  66  * RESERVE_FREE - freeing a reservation.
  67  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  68  *   ENOSPC accounting
  69  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  70  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  71  */
  72 enum {
  73         RESERVE_FREE = 0,
  74         RESERVE_ALLOC = 1,
  75         RESERVE_ALLOC_NO_ACCOUNT = 2,
  76 };
  77
  78 static int update_block_group(struct btrfs_trans_handle *trans,
  79                               struct btrfs_root *root, u64 bytenr,
  80                               u64 num_bytes, int alloc);
  81 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  82                                 struct btrfs_root *root,
  83                                 struct btrfs_delayed_ref_node *node, u64 parent,
  84                                 u64 root_objectid, u64 owner_objectid,
  85                                 u64 owner_offset, int refs_to_drop,
  86                                 struct btrfs_delayed_extent_op *extra_op);
  87 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  88                                     struct extent_buffer *leaf,
  89                                     struct btrfs_extent_item *ei);
  90 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  91                                       struct btrfs_root *root,
  92                                       u64 parent, u64 root_objectid,
  93                                       u64 flags, u64 owner, u64 offset,
  94                                       struct btrfs_key *ins, int ref_mod);
  95 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  96                                      struct btrfs_root *root,
  97                                      u64 parent, u64 root_objectid,
  98                                      u64 flags, struct btrfs_disk_key *key,
  99                                      int level, struct btrfs_key *ins);
 100 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 101                           struct btrfs_root *extent_root, u64 flags,
 102                           int force);
 103 static int find_next_key(struct btrfs_path *path, int level,
 104                          struct btrfs_key *key);
 105 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 106                             int dump_block_groups);
 107 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 108                                        u64 num_bytes, int reserve,
 109                                        int delalloc);
 110 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 111                                u64 num_bytes);
 112 int btrfs_pin_extent(struct btrfs_root *root,
 113                      u64 bytenr, u64 num_bytes, int reserved);
 114
 115 static noinline int
 116 block_group_cache_done(struct btrfs_block_group_cache *cache)
 117 {
 118         smp_mb();
 119         return cache->cached == BTRFS_CACHE_FINISHED ||
 120                 cache->cached == BTRFS_CACHE_ERROR;
 121 }
 122
 123 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 124 {
 125         return (cache->flags & bits) == bits;
 126 }
 127
 128 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 129 {
 130         atomic_inc(&cache->count);
 131 }
 132
 133 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 134 {
 135         if (atomic_dec_and_test(&cache->count)) {
 136                 WARN_ON(cache->pinned > 0);
 137                 WARN_ON(cache->reserved > 0);
 138                 kfree(cache->free_space_ctl);
 139                 kfree(cache);
 140         }
 141 }
 142
 143 /*
 144  * this adds the block group to the fs_info rb tree for the block group
 145  * cache
 146  */
 147 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 148                                 struct btrfs_block_group_cache *block_group)
 149 {
 150         struct rb_node **p;
 151         struct rb_node *parent = NULL;
 152         struct btrfs_block_group_cache *cache;
 153
 154         spin_lock(&info->block_group_cache_lock);
 155         p = &info->block_group_cache_tree.rb_node;
 156
 157         while (*p) {
 158                 parent = *p;
 159                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 160                                  cache_node);
 161                 if (block_group->key.objectid < cache->key.objectid) {
 162                         p = &(*p)->rb_left;
 163                 } else if (block_group->key.objectid > cache->key.objectid) {
 164                         p = &(*p)->rb_right;
 165                 } else {
 166                         spin_unlock(&info->block_group_cache_lock);
 167                         return -EEXIST;
 168                 }
 169         }
 170
 171         rb_link_node(&block_group->cache_node, parent, p);
 172         rb_insert_color(&block_group->cache_node,
 173                         &info->block_group_cache_tree);
 174
 175         if (info->first_logical_byte > block_group->key.objectid)
 176                 info->first_logical_byte = block_group->key.objectid;
 177
 178         spin_unlock(&info->block_group_cache_lock);
 179
 180         return 0;
 181 }
 182
 183 /*
 184  * This will return the block group at or after bytenr if contains is 0, else
 185  * it will return the block group that contains the bytenr
 186  */
 187 static struct btrfs_block_group_cache *
 188 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 189                               int contains)
 190 {
 191         struct btrfs_block_group_cache *cache, *ret = NULL;
 192         struct rb_node *n;
 193         u64 end, start;
 194
 195         spin_lock(&info->block_group_cache_lock);
 196         n = info->block_group_cache_tree.rb_node;
 197
 198         while (n) {
 199                 cache = rb_entry(n, struct btrfs_block_group_cache,
 200                                  cache_node);
 201                 end = cache->key.objectid + cache->key.offset - 1;
 202                 start = cache->key.objectid;
 203
 204                 if (bytenr < start) {
 205                         if (!contains && (!ret || start < ret->key.objectid))
 206                                 ret = cache;
 207                         n = n->rb_left;
 208                 } else if (bytenr > start) {
 209                         if (contains && bytenr <= end) {
 210                                 ret = cache;
 211                                 break;
 212                         }
 213                         n = n->rb_right;
 214                 } else {
 215                         ret = cache;
 216                         break;
 217                 }
 218         }
 219         if (ret) {
 220                 btrfs_get_block_group(ret);
 221                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 222                         info->first_logical_byte = ret->key.objectid;
 223         }
 224         spin_unlock(&info->block_group_cache_lock);
 225
 226         return ret;
 227 }
 228
 229 static int add_excluded_extent(struct btrfs_root *root,
 230                                u64 start, u64 num_bytes)
 231 {
 232         u64 end = start + num_bytes - 1;
 233         set_extent_bits(&root->fs_info->freed_extents[0],
 234                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 235         set_extent_bits(&root->fs_info->freed_extents[1],
 236                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 237         return 0;
 238 }
 239
 240 static void free_excluded_extents(struct btrfs_root *root,
 241                                   struct btrfs_block_group_cache *cache)
 242 {
 243         u64 start, end;
 244
 245         start = cache->key.objectid;
 246         end = start + cache->key.offset - 1;
 247
 248         clear_extent_bits(&root->fs_info->freed_extents[0],
 249                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 250         clear_extent_bits(&root->fs_info->freed_extents[1],
 251                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 252 }
 253
 254 static int exclude_super_stripes(struct btrfs_root *root,
 255                                  struct btrfs_block_group_cache *cache)
 256 {
 257         u64 bytenr;
 258         u64 *logical;
 259         int stripe_len;
 260         int i, nr, ret;
 261
 262         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 263                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 264                 cache->bytes_super += stripe_len;
 265                 ret = add_excluded_extent(root, cache->key.objectid,
 266                                           stripe_len);
 267                 if (ret)
 268                         return ret;
 269         }
 270
 271         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 272                 bytenr = btrfs_sb_offset(i);
 273                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 274                                        cache->key.objectid, bytenr,
 275                                        0, &logical, &nr, &stripe_len);
 276                 if (ret)
 277                         return ret;
 278
 279                 while (nr--) {
 280                         u64 start, len;
 281
 282                         if (logical[nr] > cache->key.objectid +
 283                             cache->key.offset)
 284                                 continue;
 285
 286                         if (logical[nr] + stripe_len <= cache->key.objectid)
 287                                 continue;
 288
 289                         start = logical[nr];
 290                         if (start < cache->key.objectid) {
 291                                 start = cache->key.objectid;
 292                                 len = (logical[nr] + stripe_len) - start;
 293                         } else {
 294                                 len = min_t(u64, stripe_len,
 295                                             cache->key.objectid +
 296                                             cache->key.offset - start);
 297                         }
 298
 299                         cache->bytes_super += len;
 300                         ret = add_excluded_extent(root, start, len);
 301                         if (ret) {
 302                                 kfree(logical);
 303                                 return ret;
 304                         }
 305                 }
 306
 307                 kfree(logical);
 308         }
 309         return 0;
 310 }
 311
 312 static struct btrfs_caching_control *
 313 get_caching_control(struct btrfs_block_group_cache *cache)
 314 {
 315         struct btrfs_caching_control *ctl;
 316
 317         spin_lock(&cache->lock);
 318         if (!cache->caching_ctl) {
 319                 spin_unlock(&cache->lock);
 320                 return NULL;
 321         }
 322
 323         ctl = cache->caching_ctl;
 324         atomic_inc(&ctl->count);
 325         spin_unlock(&cache->lock);
 326         return ctl;
 327 }
 328
 329 static void put_caching_control(struct btrfs_caching_control *ctl)
 330 {
 331         if (atomic_dec_and_test(&ctl->count))
 332                 kfree(ctl);
 333 }
 334
 335 #ifdef CONFIG_BTRFS_DEBUG
 336 static void fragment_free_space(struct btrfs_root *root,
 337                                 struct btrfs_block_group_cache *block_group)
 338 {
 339         u64 start = block_group->key.objectid;
 340         u64 len = block_group->key.offset;
 341         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 342                 root->nodesize : root->sectorsize;
 343         u64 step = chunk << 1;
 344
 345         while (len > chunk) {
 346                 btrfs_remove_free_space(block_group, start, chunk);
 347                 start += step;
 348                 if (len < step)
 349                         len = 0;
 350                 else
 351                         len -= step;
 352         }
 353 }
 354 #endif
 355
 356 /*
 357  * this is only called by cache_block_group, since we could have freed extents
 358  * we need to check the pinned_extents for any extents that can't be used yet
 359  * since their free space will be released as soon as the transaction commits.
 360  */
 361 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 362                        struct btrfs_fs_info *info, u64 start, u64 end)
 363 {
 364         u64 extent_start, extent_end, size, total_added = 0;
 365         int ret;
 366
 367         while (start < end) {
 368                 ret = find_first_extent_bit(info->pinned_extents, start,
 369                                             &extent_start, &extent_end,
 370                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 371                                             NULL);
 372                 if (ret)
 373                         break;
 374
 375                 if (extent_start <= start) {
 376                         start = extent_end + 1;
 377                 } else if (extent_start > start && extent_start < end) {
 378                         size = extent_start - start;
 379                         total_added += size;
 380                         ret = btrfs_add_free_space(block_group, start,
 381                                                    size);
 382                         BUG_ON(ret); /* -ENOMEM or logic error */
 383                         start = extent_end + 1;
 384                 } else {
 385                         break;
 386                 }
 387         }
 388
 389         if (start < end) {
 390                 size = end - start;
 391                 total_added += size;
 392                 ret = btrfs_add_free_space(block_group, start, size);
 393                 BUG_ON(ret); /* -ENOMEM or logic error */
 394         }
 395
 396         return total_added;
 397 }
 398
 399 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 400 {
 401         struct btrfs_block_group_cache *block_group;
 402         struct btrfs_fs_info *fs_info;
 403         struct btrfs_root *extent_root;
 404         struct btrfs_path *path;
 405         struct extent_buffer *leaf;
 406         struct btrfs_key key;
 407         u64 total_found = 0;
 408         u64 last = 0;
 409         u32 nritems;
 410         int ret;
 411         bool wakeup = true;
 412
 413         block_group = caching_ctl->block_group;
 414         fs_info = block_group->fs_info;
 415         extent_root = fs_info->extent_root;
 416
 417         path = btrfs_alloc_path();
 418         if (!path)
 419                 return -ENOMEM;
 420
 421         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 422
 423 #ifdef CONFIG_BTRFS_DEBUG
 424         /*
 425          * If we're fragmenting we don't want to make anybody think we can
 426          * allocate from this block group until we've had a chance to fragment
 427          * the free space.
 428          */
 429         if (btrfs_should_fragment_free_space(extent_root, block_group))
 430                 wakeup = false;
 431 #endif
 432         /*
 433          * We don't want to deadlock with somebody trying to allocate a new
 434          * extent for the extent root while also trying to search the extent
 435          * root to add free space.  So we skip locking and search the commit
 436          * root, since its read-only
 437          */
 438         path->skip_locking = 1;
 439         path->search_commit_root = 1;
 440         path->reada = READA_FORWARD;
 441
 442         key.objectid = last;
 443         key.offset = 0;
 444         key.type = BTRFS_EXTENT_ITEM_KEY;
 445
 446 next:
 447         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 448         if (ret < 0)
 449                 goto out;
 450
 451         leaf = path->nodes[0];
 452         nritems = btrfs_header_nritems(leaf);
 453
 454         while (1) {
 455                 if (btrfs_fs_closing(fs_info) > 1) {
 456                         last = (u64)-1;
 457                         break;
 458                 }
 459
 460                 if (path->slots[0] < nritems) {
 461                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 462                 } else {
 463                         ret = find_next_key(path, 0, &key);
 464                         if (ret)
 465                                 break;
 466
 467                         if (need_resched() ||
 468                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 469                                 if (wakeup)
 470                                         caching_ctl->progress = last;
 471                                 btrfs_release_path(path);
 472                                 up_read(&fs_info->commit_root_sem);
 473                                 mutex_unlock(&caching_ctl->mutex);
 474                                 cond_resched();
 475                                 mutex_lock(&caching_ctl->mutex);
 476                                 down_read(&fs_info->commit_root_sem);
 477                                 goto next;
 478                         }
 479
 480                         ret = btrfs_next_leaf(extent_root, path);
 481                         if (ret < 0)
 482                                 goto out;
 483                         if (ret)
 484                                 break;
 485                         leaf = path->nodes[0];
 486                         nritems = btrfs_header_nritems(leaf);
 487                         continue;
 488                 }
 489
 490                 if (key.objectid < last) {
 491                         key.objectid = last;
 492                         key.offset = 0;
 493                         key.type = BTRFS_EXTENT_ITEM_KEY;
 494
 495                         if (wakeup)
 496                                 caching_ctl->progress = last;
 497                         btrfs_release_path(path);
 498                         goto next;
 499                 }
 500
 501                 if (key.objectid < block_group->key.objectid) {
 502                         path->slots[0]++;
 503                         continue;
 504                 }
 505
 506                 if (key.objectid >= block_group->key.objectid +
 507                     block_group->key.offset)
 508                         break;
 509
 510                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 511                     key.type == BTRFS_METADATA_ITEM_KEY) {
 512                         total_found += add_new_free_space(block_group,
 513                                                           fs_info, last,
 514                                                           key.objectid);
 515                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 516                                 last = key.objectid +
 517                                         fs_info->tree_root->nodesize;
 518                         else
 519                                 last = key.objectid + key.offset;
 520
 521                         if (total_found > CACHING_CTL_WAKE_UP) {
 522                                 total_found = 0;
 523                                 if (wakeup)
 524                                         wake_up(&caching_ctl->wait);
 525                         }
 526                 }
 527                 path->slots[0]++;
 528         }
 529         ret = 0;
 530
 531         total_found += add_new_free_space(block_group, fs_info, last,
 532                                           block_group->key.objectid +
 533                                           block_group->key.offset);
 534         caching_ctl->progress = (u64)-1;
 535
 536 out:
 537         btrfs_free_path(path);
 538         return ret;
 539 }
 540
 541 static noinline void caching_thread(struct btrfs_work *work)
 542 {
 543         struct btrfs_block_group_cache *block_group;
 544         struct btrfs_fs_info *fs_info;
 545         struct btrfs_caching_control *caching_ctl;
 546         struct btrfs_root *extent_root;
 547         int ret;
 548
 549         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 550         block_group = caching_ctl->block_group;
 551         fs_info = block_group->fs_info;
 552         extent_root = fs_info->extent_root;
 553
 554         mutex_lock(&caching_ctl->mutex);
 555         down_read(&fs_info->commit_root_sem);
 556
 557         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 558                 ret = load_free_space_tree(caching_ctl);
 559         else
 560                 ret = load_extent_tree_free(caching_ctl);
 561
 562         spin_lock(&block_group->lock);
 563         block_group->caching_ctl = NULL;
 564         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 565         spin_unlock(&block_group->lock);
 566
 567 #ifdef CONFIG_BTRFS_DEBUG
 568         if (btrfs_should_fragment_free_space(extent_root, block_group)) {
 569                 u64 bytes_used;
 570
 571                 spin_lock(&block_group->space_info->lock);
 572                 spin_lock(&block_group->lock);
 573                 bytes_used = block_group->key.offset -
 574                         btrfs_block_group_used(&block_group->item);
 575                 block_group->space_info->bytes_used += bytes_used >> 1;
 576                 spin_unlock(&block_group->lock);
 577                 spin_unlock(&block_group->space_info->lock);
 578                 fragment_free_space(extent_root, block_group);
 579         }
 580 #endif
 581
 582         caching_ctl->progress = (u64)-1;
 583
 584         up_read(&fs_info->commit_root_sem);
 585         free_excluded_extents(fs_info->extent_root, block_group);
 586         mutex_unlock(&caching_ctl->mutex);
 587
 588         wake_up(&caching_ctl->wait);
 589
 590         put_caching_control(caching_ctl);
 591         btrfs_put_block_group(block_group);
 592 }
 593
 594 static int cache_block_group(struct btrfs_block_group_cache *cache,
 595                              int load_cache_only)
 596 {
 597         DEFINE_WAIT(wait);
 598         struct btrfs_fs_info *fs_info = cache->fs_info;
 599         struct btrfs_caching_control *caching_ctl;
 600         int ret = 0;
 601
 602         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 603         if (!caching_ctl)
 604                 return -ENOMEM;
 605
 606         INIT_LIST_HEAD(&caching_ctl->list);
 607         mutex_init(&caching_ctl->mutex);
 608         init_waitqueue_head(&caching_ctl->wait);
 609         caching_ctl->block_group = cache;
 610         caching_ctl->progress = cache->key.objectid;
 611         atomic_set(&caching_ctl->count, 1);
 612         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 613                         caching_thread, NULL, NULL);
 614
 615         spin_lock(&cache->lock);
 616         /*
 617          * This should be a rare occasion, but this could happen I think in the
 618          * case where one thread starts to load the space cache info, and then
 619          * some other thread starts a transaction commit which tries to do an
 620          * allocation while the other thread is still loading the space cache
 621          * info.  The previous loop should have kept us from choosing this block
 622          * group, but if we've moved to the state where we will wait on caching
 623          * block groups we need to first check if we're doing a fast load here,
 624          * so we can wait for it to finish, otherwise we could end up allocating
 625          * from a block group who's cache gets evicted for one reason or
 626          * another.
 627          */
 628         while (cache->cached == BTRFS_CACHE_FAST) {
 629                 struct btrfs_caching_control *ctl;
 630
 631                 ctl = cache->caching_ctl;
 632                 atomic_inc(&ctl->count);
 633                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 634                 spin_unlock(&cache->lock);
 635
 636                 schedule();
 637
 638                 finish_wait(&ctl->wait, &wait);
 639                 put_caching_control(ctl);
 640                 spin_lock(&cache->lock);
 641         }
 642
 643         if (cache->cached != BTRFS_CACHE_NO) {
 644                 spin_unlock(&cache->lock);
 645                 kfree(caching_ctl);
 646                 return 0;
 647         }
 648         WARN_ON(cache->caching_ctl);
 649         cache->caching_ctl = caching_ctl;
 650         cache->cached = BTRFS_CACHE_FAST;
 651         spin_unlock(&cache->lock);
 652
 653         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 654                 mutex_lock(&caching_ctl->mutex);
 655                 ret = load_free_space_cache(fs_info, cache);
 656
 657                 spin_lock(&cache->lock);
 658                 if (ret == 1) {
 659                         cache->caching_ctl = NULL;
 660                         cache->cached = BTRFS_CACHE_FINISHED;
 661                         cache->last_byte_to_unpin = (u64)-1;
 662                         caching_ctl->progress = (u64)-1;
 663                 } else {
 664                         if (load_cache_only) {
 665                                 cache->caching_ctl = NULL;
 666                                 cache->cached = BTRFS_CACHE_NO;
 667                         } else {
 668                                 cache->cached = BTRFS_CACHE_STARTED;
 669                                 cache->has_caching_ctl = 1;
 670                         }
 671                 }
 672                 spin_unlock(&cache->lock);
 673 #ifdef CONFIG_BTRFS_DEBUG
 674                 if (ret == 1 &&
 675                     btrfs_should_fragment_free_space(fs_info->extent_root,
 676                                                      cache)) {
 677                         u64 bytes_used;
 678
 679                         spin_lock(&cache->space_info->lock);
 680                         spin_lock(&cache->lock);
 681                         bytes_used = cache->key.offset -
 682                                 btrfs_block_group_used(&cache->item);
 683                         cache->space_info->bytes_used += bytes_used >> 1;
 684                         spin_unlock(&cache->lock);
 685                         spin_unlock(&cache->space_info->lock);
 686                         fragment_free_space(fs_info->extent_root, cache);
 687                 }
 688 #endif
 689                 mutex_unlock(&caching_ctl->mutex);
 690
 691                 wake_up(&caching_ctl->wait);
 692                 if (ret == 1) {
 693                         put_caching_control(caching_ctl);
 694                         free_excluded_extents(fs_info->extent_root, cache);
 695                         return 0;
 696                 }
 697         } else {
 698                 /*
 699                  * We're either using the free space tree or no caching at all.
 700                  * Set cached to the appropriate value and wakeup any waiters.
 701                  */
 702                 spin_lock(&cache->lock);
 703                 if (load_cache_only) {
 704                         cache->caching_ctl = NULL;
 705                         cache->cached = BTRFS_CACHE_NO;
 706                 } else {
 707                         cache->cached = BTRFS_CACHE_STARTED;
 708                         cache->has_caching_ctl = 1;
 709                 }
 710                 spin_unlock(&cache->lock);
 711                 wake_up(&caching_ctl->wait);
 712         }
 713
 714         if (load_cache_only) {
 715                 put_caching_control(caching_ctl);
 716                 return 0;
 717         }
 718
 719         down_write(&fs_info->commit_root_sem);
 720         atomic_inc(&caching_ctl->count);
 721         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 722         up_write(&fs_info->commit_root_sem);
 723
 724         btrfs_get_block_group(cache);
 725
 726         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 727
 728         return ret;
 729 }
 730
 731 /*
 732  * return the block group that starts at or after bytenr
 733  */
 734 static struct btrfs_block_group_cache *
 735 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 736 {
 737         struct btrfs_block_group_cache *cache;
 738
 739         cache = block_group_cache_tree_search(info, bytenr, 0);
 740
 741         return cache;
 742 }
 743
 744 /*
 745  * return the block group that contains the given bytenr
 746  */
 747 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 748                                                  struct btrfs_fs_info *info,
 749                                                  u64 bytenr)
 750 {
 751         struct btrfs_block_group_cache *cache;
 752
 753         cache = block_group_cache_tree_search(info, bytenr, 1);
 754
 755         return cache;
 756 }
 757
 758 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 759                                                   u64 flags)
 760 {
 761         struct list_head *head = &info->space_info;
 762         struct btrfs_space_info *found;
 763
 764         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 765
 766         rcu_read_lock();
 767         list_for_each_entry_rcu(found, head, list) {
 768                 if (found->flags & flags) {
 769                         rcu_read_unlock();
 770                         return found;
 771                 }
 772         }
 773         rcu_read_unlock();
 774         return NULL;
 775 }
 776
 777 /*
 778  * after adding space to the filesystem, we need to clear the full flags
 779  * on all the space infos.
 780  */
 781 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 782 {
 783         struct list_head *head = &info->space_info;
 784         struct btrfs_space_info *found;
 785
 786         rcu_read_lock();
 787         list_for_each_entry_rcu(found, head, list)
 788                 found->full = 0;
 789         rcu_read_unlock();
 790 }
 791
 792 /* simple helper to search for an existing data extent at a given offset */
 793 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
 794 {
 795         int ret;
 796         struct btrfs_key key;
 797         struct btrfs_path *path;
 798
 799         path = btrfs_alloc_path();
 800         if (!path)
 801                 return -ENOMEM;
 802
 803         key.objectid = start;
 804         key.offset = len;
 805         key.type = BTRFS_EXTENT_ITEM_KEY;
 806         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 807                                 0, 0);
 808         btrfs_free_path(path);
 809         return ret;
 810 }
 811
 812 /*
 813  * helper function to lookup reference count and flags of a tree block.
 814  *
 815  * the head node for delayed ref is used to store the sum of all the
 816  * reference count modifications queued up in the rbtree. the head
 817  * node may also store the extent flags to set. This way you can check
 818  * to see what the reference count and extent flags would be if all of
 819  * the delayed refs are not processed.
 820  */
 821 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 822                              struct btrfs_root *root, u64 bytenr,
 823                              u64 offset, int metadata, u64 *refs, u64 *flags)
 824 {
 825         struct btrfs_delayed_ref_head *head;
 826         struct btrfs_delayed_ref_root *delayed_refs;
 827         struct btrfs_path *path;
 828         struct btrfs_extent_item *ei;
 829         struct extent_buffer *leaf;
 830         struct btrfs_key key;
 831         u32 item_size;
 832         u64 num_refs;
 833         u64 extent_flags;
 834         int ret;
 835
 836         /*
 837          * If we don't have skinny metadata, don't bother doing anything
 838          * different
 839          */
 840         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 841                 offset = root->nodesize;
 842                 metadata = 0;
 843         }
 844
 845         path = btrfs_alloc_path();
 846         if (!path)
 847                 return -ENOMEM;
 848
 849         if (!trans) {
 850                 path->skip_locking = 1;
 851                 path->search_commit_root = 1;
 852         }
 853
 854 search_again:
 855         key.objectid = bytenr;
 856         key.offset = offset;
 857         if (metadata)
 858                 key.type = BTRFS_METADATA_ITEM_KEY;
 859         else
 860                 key.type = BTRFS_EXTENT_ITEM_KEY;
 861
 862         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 863                                 &key, path, 0, 0);
 864         if (ret < 0)
 865                 goto out_free;
 866
 867         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 868                 if (path->slots[0]) {
 869                         path->slots[0]--;
 870                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 871                                               path->slots[0]);
 872                         if (key.objectid == bytenr &&
 873                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 874                             key.offset == root->nodesize)
 875                                 ret = 0;
 876                 }
 877         }
 878
 879         if (ret == 0) {
 880                 leaf = path->nodes[0];
 881                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 882                 if (item_size >= sizeof(*ei)) {
 883                         ei = btrfs_item_ptr(leaf, path->slots[0],
 884                                             struct btrfs_extent_item);
 885                         num_refs = btrfs_extent_refs(leaf, ei);
 886                         extent_flags = btrfs_extent_flags(leaf, ei);
 887                 } else {
 888 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 889                         struct btrfs_extent_item_v0 *ei0;
 890                         BUG_ON(item_size != sizeof(*ei0));
 891                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 892                                              struct btrfs_extent_item_v0);
 893                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 894                         /* FIXME: this isn't correct for data */
 895                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 896 #else
 897                         BUG();
 898 #endif
 899                 }
 900                 BUG_ON(num_refs == 0);
 901         } else {
 902                 num_refs = 0;
 903                 extent_flags = 0;
 904                 ret = 0;
 905         }
 906
 907         if (!trans)
 908                 goto out;
 909
 910         delayed_refs = &trans->transaction->delayed_refs;
 911         spin_lock(&delayed_refs->lock);
 912         head = btrfs_find_delayed_ref_head(trans, bytenr);
 913         if (head) {
 914                 if (!mutex_trylock(&head->mutex)) {
 915                         atomic_inc(&head->node.refs);
 916                         spin_unlock(&delayed_refs->lock);
 917
 918                         btrfs_release_path(path);
 919
 920                         /*
 921                          * Mutex was contended, block until it's released and try
 922                          * again
 923                          */
 924                         mutex_lock(&head->mutex);
 925                         mutex_unlock(&head->mutex);
 926                         btrfs_put_delayed_ref(&head->node);
 927                         goto search_again;
 928                 }
 929                 spin_lock(&head->lock);
 930                 if (head->extent_op && head->extent_op->update_flags)
 931                         extent_flags |= head->extent_op->flags_to_set;
 932                 else
 933                         BUG_ON(num_refs == 0);
 934
 935                 num_refs += head->node.ref_mod;
 936                 spin_unlock(&head->lock);
 937                 mutex_unlock(&head->mutex);
 938         }
 939         spin_unlock(&delayed_refs->lock);
 940 out:
 941         WARN_ON(num_refs == 0);
 942         if (refs)
 943                 *refs = num_refs;
 944         if (flags)
 945                 *flags = extent_flags;
 946 out_free:
 947         btrfs_free_path(path);
 948         return ret;
 949 }
 950
 951 /*
 952  * Back reference rules.  Back refs have three main goals:
 953  *
 954  * 1) differentiate between all holders of references to an extent so that
 955  *    when a reference is dropped we can make sure it was a valid reference
 956  *    before freeing the extent.
 957  *
 958  * 2) Provide enough information to quickly find the holders of an extent
 959  *    if we notice a given block is corrupted or bad.
 960  *
 961  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 962  *    maintenance.  This is actually the same as #2, but with a slightly
 963  *    different use case.
 964  *
 965  * There are two kinds of back refs. The implicit back refs is optimized
 966  * for pointers in non-shared tree blocks. For a given pointer in a block,
 967  * back refs of this kind provide information about the block's owner tree
 968  * and the pointer's key. These information allow us to find the block by
 969  * b-tree searching. The full back refs is for pointers in tree blocks not
 970  * referenced by their owner trees. The location of tree block is recorded
 971  * in the back refs. Actually the full back refs is generic, and can be
 972  * used in all cases the implicit back refs is used. The major shortcoming
 973  * of the full back refs is its overhead. Every time a tree block gets
 974  * COWed, we have to update back refs entry for all pointers in it.
 975  *
 976  * For a newly allocated tree block, we use implicit back refs for
 977  * pointers in it. This means most tree related operations only involve
 978  * implicit back refs. For a tree block created in old transaction, the
 979  * only way to drop a reference to it is COW it. So we can detect the
 980  * event that tree block loses its owner tree's reference and do the
 981  * back refs conversion.
 982  *
 983  * When a tree block is COW'd through a tree, there are four cases:
 984  *
 985  * The reference count of the block is one and the tree is the block's
 986  * owner tree. Nothing to do in this case.
 987  *
 988  * The reference count of the block is one and the tree is not the
 989  * block's owner tree. In this case, full back refs is used for pointers
 990  * in the block. Remove these full back refs, add implicit back refs for
 991  * every pointers in the new block.
 992  *
 993  * The reference count of the block is greater than one and the tree is
 994  * the block's owner tree. In this case, implicit back refs is used for
 995  * pointers in the block. Add full back refs for every pointers in the
 996  * block, increase lower level extents' reference counts. The original
 997  * implicit back refs are entailed to the new block.
 998  *
 999  * The reference count of the block is greater than one and the tree is
1000  * not the block's owner tree. Add implicit back refs for every pointer in
1001  * the new block, increase lower level extents' reference count.
1002  *
1003  * Back Reference Key composing:
1004  *
1005  * The key objectid corresponds to the first byte in the extent,
1006  * The key type is used to differentiate between types of back refs.
1007  * There are different meanings of the key offset for different types
1008  * of back refs.
1009  *
1010  * File extents can be referenced by:
1011  *
1012  * - multiple snapshots, subvolumes, or different generations in one subvol
1013  * - different files inside a single subvolume
1014  * - different offsets inside a file (bookend extents in file.c)
1015  *
1016  * The extent ref structure for the implicit back refs has fields for:
1017  *
1018  * - Objectid of the subvolume root
1019  * - objectid of the file holding the reference
1020  * - original offset in the file
1021  * - how many bookend extents
1022  *
1023  * The key offset for the implicit back refs is hash of the first
1024  * three fields.
1025  *
1026  * The extent ref structure for the full back refs has field for:
1027  *
1028  * - number of pointers in the tree leaf
1029  *
1030  * The key offset for the implicit back refs is the first byte of
1031  * the tree leaf
1032  *
1033  * When a file extent is allocated, The implicit back refs is used.
1034  * the fields are filled in:
1035  *
1036  *     (root_key.objectid, inode objectid, offset in file, 1)
1037  *
1038  * When a file extent is removed file truncation, we find the
1039  * corresponding implicit back refs and check the following fields:
1040  *
1041  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1042  *
1043  * Btree extents can be referenced by:
1044  *
1045  * - Different subvolumes
1046  *
1047  * Both the implicit back refs and the full back refs for tree blocks
1048  * only consist of key. The key offset for the implicit back refs is
1049  * objectid of block's owner tree. The key offset for the full back refs
1050  * is the first byte of parent block.
1051  *
1052  * When implicit back refs is used, information about the lowest key and
1053  * level of the tree block are required. These information are stored in
1054  * tree block info structure.
1055  */
1056
1057 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1058 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1059                                   struct btrfs_root *root,
1060                                   struct btrfs_path *path,
1061                                   u64 owner, u32 extra_size)
1062 {
1063         struct btrfs_extent_item *item;
1064         struct btrfs_extent_item_v0 *ei0;
1065         struct btrfs_extent_ref_v0 *ref0;
1066         struct btrfs_tree_block_info *bi;
1067         struct extent_buffer *leaf;
1068         struct btrfs_key key;
1069         struct btrfs_key found_key;
1070         u32 new_size = sizeof(*item);
1071         u64 refs;
1072         int ret;
1073
1074         leaf = path->nodes[0];
1075         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1076
1077         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1078         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1079                              struct btrfs_extent_item_v0);
1080         refs = btrfs_extent_refs_v0(leaf, ei0);
1081
1082         if (owner == (u64)-1) {
1083                 while (1) {
1084                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1085                                 ret = btrfs_next_leaf(root, path);
1086                                 if (ret < 0)
1087                                         return ret;
1088                                 BUG_ON(ret > 0); /* Corruption */
1089                                 leaf = path->nodes[0];
1090                         }
1091                         btrfs_item_key_to_cpu(leaf, &found_key,
1092                                               path->slots[0]);
1093                         BUG_ON(key.objectid != found_key.objectid);
1094                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1095                                 path->slots[0]++;
1096                                 continue;
1097                         }
1098                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1099                                               struct btrfs_extent_ref_v0);
1100                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1101                         break;
1102                 }
1103         }
1104         btrfs_release_path(path);
1105
1106         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1107                 new_size += sizeof(*bi);
1108
1109         new_size -= sizeof(*ei0);
1110         ret = btrfs_search_slot(trans, root, &key, path,
1111                                 new_size + extra_size, 1);
1112         if (ret < 0)
1113                 return ret;
1114         BUG_ON(ret); /* Corruption */
1115
1116         btrfs_extend_item(root, path, new_size);
1117
1118         leaf = path->nodes[0];
1119         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1120         btrfs_set_extent_refs(leaf, item, refs);
1121         /* FIXME: get real generation */
1122         btrfs_set_extent_generation(leaf, item, 0);
1123         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1124                 btrfs_set_extent_flags(leaf, item,
1125                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1126                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1127                 bi = (struct btrfs_tree_block_info *)(item + 1);
1128                 /* FIXME: get first key of the block */
1129                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1130                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1131         } else {
1132                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1133         }
1134         btrfs_mark_buffer_dirty(leaf);
1135         return 0;
1136 }
1137 #endif
1138
1139 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1140 {
1141         u32 high_crc = ~(u32)0;
1142         u32 low_crc = ~(u32)0;
1143         __le64 lenum;
1144
1145         lenum = cpu_to_le64(root_objectid);
1146         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1147         lenum = cpu_to_le64(owner);
1148         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1149         lenum = cpu_to_le64(offset);
1150         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1151
1152         return ((u64)high_crc << 31) ^ (u64)low_crc;
1153 }
1154
1155 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1156                                      struct btrfs_extent_data_ref *ref)
1157 {
1158         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1159                                     btrfs_extent_data_ref_objectid(leaf, ref),
1160                                     btrfs_extent_data_ref_offset(leaf, ref));
1161 }
1162
1163 static int match_extent_data_ref(struct extent_buffer *leaf,
1164                                  struct btrfs_extent_data_ref *ref,
1165                                  u64 root_objectid, u64 owner, u64 offset)
1166 {
1167         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1168             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1169             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1170                 return 0;
1171         return 1;
1172 }
1173
1174 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1175                                            struct btrfs_root *root,
1176                                            struct btrfs_path *path,
1177                                            u64 bytenr, u64 parent,
1178                                            u64 root_objectid,
1179                                            u64 owner, u64 offset)
1180 {
1181         struct btrfs_key key;
1182         struct btrfs_extent_data_ref *ref;
1183         struct extent_buffer *leaf;
1184         u32 nritems;
1185         int ret;
1186         int recow;
1187         int err = -ENOENT;
1188
1189         key.objectid = bytenr;
1190         if (parent) {
1191                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1192                 key.offset = parent;
1193         } else {
1194                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1195                 key.offset = hash_extent_data_ref(root_objectid,
1196                                                   owner, offset);
1197         }
1198 again:
1199         recow = 0;
1200         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1201         if (ret < 0) {
1202                 err = ret;
1203                 goto fail;
1204         }
1205
1206         if (parent) {
1207                 if (!ret)
1208                         return 0;
1209 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1210                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1211                 btrfs_release_path(path);
1212                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1213                 if (ret < 0) {
1214                         err = ret;
1215                         goto fail;
1216                 }
1217                 if (!ret)
1218                         return 0;
1219 #endif
1220                 goto fail;
1221         }
1222
1223         leaf = path->nodes[0];
1224         nritems = btrfs_header_nritems(leaf);
1225         while (1) {
1226                 if (path->slots[0] >= nritems) {
1227                         ret = btrfs_next_leaf(root, path);
1228                         if (ret < 0)
1229                                 err = ret;
1230                         if (ret)
1231                                 goto fail;
1232
1233                         leaf = path->nodes[0];
1234                         nritems = btrfs_header_nritems(leaf);
1235                         recow = 1;
1236                 }
1237
1238                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1239                 if (key.objectid != bytenr ||
1240                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1241                         goto fail;
1242
1243                 ref = btrfs_item_ptr(leaf, path->slots[0],
1244                                      struct btrfs_extent_data_ref);
1245
1246                 if (match_extent_data_ref(leaf, ref, root_objectid,
1247                                           owner, offset)) {
1248                         if (recow) {
1249                                 btrfs_release_path(path);
1250                                 goto again;
1251                         }
1252                         err = 0;
1253                         break;
1254                 }
1255                 path->slots[0]++;
1256         }
1257 fail:
1258         return err;
1259 }
1260
1261 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1262                                            struct btrfs_root *root,
1263                                            struct btrfs_path *path,
1264                                            u64 bytenr, u64 parent,
1265                                            u64 root_objectid, u64 owner,
1266                                            u64 offset, int refs_to_add)
1267 {
1268         struct btrfs_key key;
1269         struct extent_buffer *leaf;
1270         u32 size;
1271         u32 num_refs;
1272         int ret;
1273
1274         key.objectid = bytenr;
1275         if (parent) {
1276                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1277                 key.offset = parent;
1278                 size = sizeof(struct btrfs_shared_data_ref);
1279         } else {
1280                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1281                 key.offset = hash_extent_data_ref(root_objectid,
1282                                                   owner, offset);
1283                 size = sizeof(struct btrfs_extent_data_ref);
1284         }
1285
1286         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1287         if (ret && ret != -EEXIST)
1288                 goto fail;
1289
1290         leaf = path->nodes[0];
1291         if (parent) {
1292                 struct btrfs_shared_data_ref *ref;
1293                 ref = btrfs_item_ptr(leaf, path->slots[0],
1294                                      struct btrfs_shared_data_ref);
1295                 if (ret == 0) {
1296                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1297                 } else {
1298                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1299                         num_refs += refs_to_add;
1300                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1301                 }
1302         } else {
1303                 struct btrfs_extent_data_ref *ref;
1304                 while (ret == -EEXIST) {
1305                         ref = btrfs_item_ptr(leaf, path->slots[0],
1306                                              struct btrfs_extent_data_ref);
1307                         if (match_extent_data_ref(leaf, ref, root_objectid,
1308                                                   owner, offset))
1309                                 break;
1310                         btrfs_release_path(path);
1311                         key.offset++;
1312                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1313                                                       size);
1314                         if (ret && ret != -EEXIST)
1315                                 goto fail;
1316
1317                         leaf = path->nodes[0];
1318                 }
1319                 ref = btrfs_item_ptr(leaf, path->slots[0],
1320                                      struct btrfs_extent_data_ref);
1321                 if (ret == 0) {
1322                         btrfs_set_extent_data_ref_root(leaf, ref,
1323                                                        root_objectid);
1324                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1325                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1326                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1327                 } else {
1328                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1329                         num_refs += refs_to_add;
1330                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1331                 }
1332         }
1333         btrfs_mark_buffer_dirty(leaf);
1334         ret = 0;
1335 fail:
1336         btrfs_release_path(path);
1337         return ret;
1338 }
1339
1340 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1341                                            struct btrfs_root *root,
1342                                            struct btrfs_path *path,
1343                                            int refs_to_drop, int *last_ref)
1344 {
1345         struct btrfs_key key;
1346         struct btrfs_extent_data_ref *ref1 = NULL;
1347         struct btrfs_shared_data_ref *ref2 = NULL;
1348         struct extent_buffer *leaf;
1349         u32 num_refs = 0;
1350         int ret = 0;
1351
1352         leaf = path->nodes[0];
1353         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1354
1355         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1356                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1357                                       struct btrfs_extent_data_ref);
1358                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1359         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1360                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1361                                       struct btrfs_shared_data_ref);
1362                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1363 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1364         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1365                 struct btrfs_extent_ref_v0 *ref0;
1366                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1367                                       struct btrfs_extent_ref_v0);
1368                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1369 #endif
1370         } else {
1371                 BUG();
1372         }
1373
1374         BUG_ON(num_refs < refs_to_drop);
1375         num_refs -= refs_to_drop;
1376
1377         if (num_refs == 0) {
1378                 ret = btrfs_del_item(trans, root, path);
1379                 *last_ref = 1;
1380         } else {
1381                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1382                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1383                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1384                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1385 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1386                 else {
1387                         struct btrfs_extent_ref_v0 *ref0;
1388                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1389                                         struct btrfs_extent_ref_v0);
1390                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1391                 }
1392 #endif
1393                 btrfs_mark_buffer_dirty(leaf);
1394         }
1395         return ret;
1396 }
1397
1398 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1399                                           struct btrfs_extent_inline_ref *iref)
1400 {
1401         struct btrfs_key key;
1402         struct extent_buffer *leaf;
1403         struct btrfs_extent_data_ref *ref1;
1404         struct btrfs_shared_data_ref *ref2;
1405         u32 num_refs = 0;
1406
1407         leaf = path->nodes[0];
1408         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1409         if (iref) {
1410                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1411                     BTRFS_EXTENT_DATA_REF_KEY) {
1412                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1413                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1414                 } else {
1415                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1416                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1417                 }
1418         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1419                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1420                                       struct btrfs_extent_data_ref);
1421                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1422         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1423                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1424                                       struct btrfs_shared_data_ref);
1425                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1426 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1427         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1428                 struct btrfs_extent_ref_v0 *ref0;
1429                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1430                                       struct btrfs_extent_ref_v0);
1431                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1432 #endif
1433         } else {
1434                 WARN_ON(1);
1435         }
1436         return num_refs;
1437 }
1438
1439 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1440                                           struct btrfs_root *root,
1441                                           struct btrfs_path *path,
1442                                           u64 bytenr, u64 parent,
1443                                           u64 root_objectid)
1444 {
1445         struct btrfs_key key;
1446         int ret;
1447
1448         key.objectid = bytenr;
1449         if (parent) {
1450                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1451                 key.offset = parent;
1452         } else {
1453                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1454                 key.offset = root_objectid;
1455         }
1456
1457         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1458         if (ret > 0)
1459                 ret = -ENOENT;
1460 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1461         if (ret == -ENOENT && parent) {
1462                 btrfs_release_path(path);
1463                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1464                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1465                 if (ret > 0)
1466                         ret = -ENOENT;
1467         }
1468 #endif
1469         return ret;
1470 }
1471
1472 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1473                                           struct btrfs_root *root,
1474                                           struct btrfs_path *path,
1475                                           u64 bytenr, u64 parent,
1476                                           u64 root_objectid)
1477 {
1478         struct btrfs_key key;
1479         int ret;
1480
1481         key.objectid = bytenr;
1482         if (parent) {
1483                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1484                 key.offset = parent;
1485         } else {
1486                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1487                 key.offset = root_objectid;
1488         }
1489
1490         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1491         btrfs_release_path(path);
1492         return ret;
1493 }
1494
1495 static inline int extent_ref_type(u64 parent, u64 owner)
1496 {
1497         int type;
1498         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1499                 if (parent > 0)
1500                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1501                 else
1502                         type = BTRFS_TREE_BLOCK_REF_KEY;
1503         } else {
1504                 if (parent > 0)
1505                         type = BTRFS_SHARED_DATA_REF_KEY;
1506                 else
1507                         type = BTRFS_EXTENT_DATA_REF_KEY;
1508         }
1509         return type;
1510 }
1511
1512 static int find_next_key(struct btrfs_path *path, int level,
1513                          struct btrfs_key *key)
1514
1515 {
1516         for (; level < BTRFS_MAX_LEVEL; level++) {
1517                 if (!path->nodes[level])
1518                         break;
1519                 if (path->slots[level] + 1 >=
1520                     btrfs_header_nritems(path->nodes[level]))
1521                         continue;
1522                 if (level == 0)
1523                         btrfs_item_key_to_cpu(path->nodes[level], key,
1524                                               path->slots[level] + 1);
1525                 else
1526                         btrfs_node_key_to_cpu(path->nodes[level], key,
1527                                               path->slots[level] + 1);
1528                 return 0;
1529         }
1530         return 1;
1531 }
1532
1533 /*
1534  * look for inline back ref. if back ref is found, *ref_ret is set
1535  * to the address of inline back ref, and 0 is returned.
1536  *
1537  * if back ref isn't found, *ref_ret is set to the address where it
1538  * should be inserted, and -ENOENT is returned.
1539  *
1540  * if insert is true and there are too many inline back refs, the path
1541  * points to the extent item, and -EAGAIN is returned.
1542  *
1543  * NOTE: inline back refs are ordered in the same way that back ref
1544  *       items in the tree are ordered.
1545  */
1546 static noinline_for_stack
1547 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1548                                  struct btrfs_root *root,
1549                                  struct btrfs_path *path,
1550                                  struct btrfs_extent_inline_ref **ref_ret,
1551                                  u64 bytenr, u64 num_bytes,
1552                                  u64 parent, u64 root_objectid,
1553                                  u64 owner, u64 offset, int insert)
1554 {
1555         struct btrfs_key key;
1556         struct extent_buffer *leaf;
1557         struct btrfs_extent_item *ei;
1558         struct btrfs_extent_inline_ref *iref;
1559         u64 flags;
1560         u64 item_size;
1561         unsigned long ptr;
1562         unsigned long end;
1563         int extra_size;
1564         int type;
1565         int want;
1566         int ret;
1567         int err = 0;
1568         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1569                                                  SKINNY_METADATA);
1570
1571         key.objectid = bytenr;
1572         key.type = BTRFS_EXTENT_ITEM_KEY;
1573         key.offset = num_bytes;
1574
1575         want = extent_ref_type(parent, owner);
1576         if (insert) {
1577                 extra_size = btrfs_extent_inline_ref_size(want);
1578                 path->keep_locks = 1;
1579         } else
1580                 extra_size = -1;
1581
1582         /*
1583          * Owner is our parent level, so we can just add one to get the level
1584          * for the block we are interested in.
1585          */
1586         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1587                 key.type = BTRFS_METADATA_ITEM_KEY;
1588                 key.offset = owner;
1589         }
1590
1591 again:
1592         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1593         if (ret < 0) {
1594                 err = ret;
1595                 goto out;
1596         }
1597
1598         /*
1599          * We may be a newly converted file system which still has the old fat
1600          * extent entries for metadata, so try and see if we have one of those.
1601          */
1602         if (ret > 0 && skinny_metadata) {
1603                 skinny_metadata = false;
1604                 if (path->slots[0]) {
1605                         path->slots[0]--;
1606                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1607                                               path->slots[0]);
1608                         if (key.objectid == bytenr &&
1609                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1610                             key.offset == num_bytes)
1611                                 ret = 0;
1612                 }
1613                 if (ret) {
1614                         key.objectid = bytenr;
1615                         key.type = BTRFS_EXTENT_ITEM_KEY;
1616                         key.offset = num_bytes;
1617                         btrfs_release_path(path);
1618                         goto again;
1619                 }
1620         }
1621
1622         if (ret && !insert) {
1623                 err = -ENOENT;
1624                 goto out;
1625         } else if (WARN_ON(ret)) {
1626                 err = -EIO;
1627                 goto out;
1628         }
1629
1630         leaf = path->nodes[0];
1631         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1632 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1633         if (item_size < sizeof(*ei)) {
1634                 if (!insert) {
1635                         err = -ENOENT;
1636                         goto out;
1637                 }
1638                 ret = convert_extent_item_v0(trans, root, path, owner,
1639                                              extra_size);
1640                 if (ret < 0) {
1641                         err = ret;
1642                         goto out;
1643                 }
1644                 leaf = path->nodes[0];
1645                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1646         }
1647 #endif
1648         BUG_ON(item_size < sizeof(*ei));
1649
1650         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1651         flags = btrfs_extent_flags(leaf, ei);
1652
1653         ptr = (unsigned long)(ei + 1);
1654         end = (unsigned long)ei + item_size;
1655
1656         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1657                 ptr += sizeof(struct btrfs_tree_block_info);
1658                 BUG_ON(ptr > end);
1659         }
1660
1661         err = -ENOENT;
1662         while (1) {
1663                 if (ptr >= end) {
1664                         WARN_ON(ptr > end);
1665                         break;
1666                 }
1667                 iref = (struct btrfs_extent_inline_ref *)ptr;
1668                 type = btrfs_extent_inline_ref_type(leaf, iref);
1669                 if (want < type)
1670                         break;
1671                 if (want > type) {
1672                         ptr += btrfs_extent_inline_ref_size(type);
1673                         continue;
1674                 }
1675
1676                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1677                         struct btrfs_extent_data_ref *dref;
1678                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1679                         if (match_extent_data_ref(leaf, dref, root_objectid,
1680                                                   owner, offset)) {
1681                                 err = 0;
1682                                 break;
1683                         }
1684                         if (hash_extent_data_ref_item(leaf, dref) <
1685                             hash_extent_data_ref(root_objectid, owner, offset))
1686                                 break;
1687                 } else {
1688                         u64 ref_offset;
1689                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1690                         if (parent > 0) {
1691                                 if (parent == ref_offset) {
1692                                         err = 0;
1693                                         break;
1694                                 }
1695                                 if (ref_offset < parent)
1696                                         break;
1697                         } else {
1698                                 if (root_objectid == ref_offset) {
1699                                         err = 0;
1700                                         break;
1701                                 }
1702                                 if (ref_offset < root_objectid)
1703                                         break;
1704                         }
1705                 }
1706                 ptr += btrfs_extent_inline_ref_size(type);
1707         }
1708         if (err == -ENOENT && insert) {
1709                 if (item_size + extra_size >=
1710                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1711                         err = -EAGAIN;
1712                         goto out;
1713                 }
1714                 /*
1715                  * To add new inline back ref, we have to make sure
1716                  * there is no corresponding back ref item.
1717                  * For simplicity, we just do not add new inline back
1718                  * ref if there is any kind of item for this block
1719                  */
1720                 if (find_next_key(path, 0, &key) == 0 &&
1721                     key.objectid == bytenr &&
1722                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1723                         err = -EAGAIN;
1724                         goto out;
1725                 }
1726         }
1727         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1728 out:
1729         if (insert) {
1730                 path->keep_locks = 0;
1731                 btrfs_unlock_up_safe(path, 1);
1732         }
1733         return err;
1734 }
1735
1736 /*
1737  * helper to add new inline back ref
1738  */
1739 static noinline_for_stack
1740 void setup_inline_extent_backref(struct btrfs_root *root,
1741                                  struct btrfs_path *path,
1742                                  struct btrfs_extent_inline_ref *iref,
1743                                  u64 parent, u64 root_objectid,
1744                                  u64 owner, u64 offset, int refs_to_add,
1745                                  struct btrfs_delayed_extent_op *extent_op)
1746 {
1747         struct extent_buffer *leaf;
1748         struct btrfs_extent_item *ei;
1749         unsigned long ptr;
1750         unsigned long end;
1751         unsigned long item_offset;
1752         u64 refs;
1753         int size;
1754         int type;
1755
1756         leaf = path->nodes[0];
1757         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1758         item_offset = (unsigned long)iref - (unsigned long)ei;
1759
1760         type = extent_ref_type(parent, owner);
1761         size = btrfs_extent_inline_ref_size(type);
1762
1763         btrfs_extend_item(root, path, size);
1764
1765         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1766         refs = btrfs_extent_refs(leaf, ei);
1767         refs += refs_to_add;
1768         btrfs_set_extent_refs(leaf, ei, refs);
1769         if (extent_op)
1770                 __run_delayed_extent_op(extent_op, leaf, ei);
1771
1772         ptr = (unsigned long)ei + item_offset;
1773         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1774         if (ptr < end - size)
1775                 memmove_extent_buffer(leaf, ptr + size, ptr,
1776                                       end - size - ptr);
1777
1778         iref = (struct btrfs_extent_inline_ref *)ptr;
1779         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1780         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1781                 struct btrfs_extent_data_ref *dref;
1782                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1783                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1784                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1785                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1786                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1787         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1788                 struct btrfs_shared_data_ref *sref;
1789                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1790                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1791                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1792         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1793                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1794         } else {
1795                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1796         }
1797         btrfs_mark_buffer_dirty(leaf);
1798 }
1799
1800 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1801                                  struct btrfs_root *root,
1802                                  struct btrfs_path *path,
1803                                  struct btrfs_extent_inline_ref **ref_ret,
1804                                  u64 bytenr, u64 num_bytes, u64 parent,
1805                                  u64 root_objectid, u64 owner, u64 offset)
1806 {
1807         int ret;
1808
1809         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1810                                            bytenr, num_bytes, parent,
1811                                            root_objectid, owner, offset, 0);
1812         if (ret != -ENOENT)
1813                 return ret;
1814
1815         btrfs_release_path(path);
1816         *ref_ret = NULL;
1817
1818         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1819                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1820                                             root_objectid);
1821         } else {
1822                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1823                                              root_objectid, owner, offset);
1824         }
1825         return ret;
1826 }
1827
1828 /*
1829  * helper to update/remove inline back ref
1830  */
1831 static noinline_for_stack
1832 void update_inline_extent_backref(struct btrfs_root *root,
1833                                   struct btrfs_path *path,
1834                                   struct btrfs_extent_inline_ref *iref,
1835                                   int refs_to_mod,
1836                                   struct btrfs_delayed_extent_op *extent_op,
1837                                   int *last_ref)
1838 {
1839         struct extent_buffer *leaf;
1840         struct btrfs_extent_item *ei;
1841         struct btrfs_extent_data_ref *dref = NULL;
1842         struct btrfs_shared_data_ref *sref = NULL;
1843         unsigned long ptr;
1844         unsigned long end;
1845         u32 item_size;
1846         int size;
1847         int type;
1848         u64 refs;
1849
1850         leaf = path->nodes[0];
1851         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1852         refs = btrfs_extent_refs(leaf, ei);
1853         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1854         refs += refs_to_mod;
1855         btrfs_set_extent_refs(leaf, ei, refs);
1856         if (extent_op)
1857                 __run_delayed_extent_op(extent_op, leaf, ei);
1858
1859         type = btrfs_extent_inline_ref_type(leaf, iref);
1860
1861         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1862                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1863                 refs = btrfs_extent_data_ref_count(leaf, dref);
1864         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1865                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1866                 refs = btrfs_shared_data_ref_count(leaf, sref);
1867         } else {
1868                 refs = 1;
1869                 BUG_ON(refs_to_mod != -1);
1870         }
1871
1872         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1873         refs += refs_to_mod;
1874
1875         if (refs > 0) {
1876                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1877                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1878                 else
1879                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1880         } else {
1881                 *last_ref = 1;
1882                 size =  btrfs_extent_inline_ref_size(type);
1883                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1884                 ptr = (unsigned long)iref;
1885                 end = (unsigned long)ei + item_size;
1886                 if (ptr + size < end)
1887                         memmove_extent_buffer(leaf, ptr, ptr + size,
1888                                               end - ptr - size);
1889                 item_size -= size;
1890                 btrfs_truncate_item(root, path, item_size, 1);
1891         }
1892         btrfs_mark_buffer_dirty(leaf);
1893 }
1894
1895 static noinline_for_stack
1896 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1897                                  struct btrfs_root *root,
1898                                  struct btrfs_path *path,
1899                                  u64 bytenr, u64 num_bytes, u64 parent,
1900                                  u64 root_objectid, u64 owner,
1901                                  u64 offset, int refs_to_add,
1902                                  struct btrfs_delayed_extent_op *extent_op)
1903 {
1904         struct btrfs_extent_inline_ref *iref;
1905         int ret;
1906
1907         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1908                                            bytenr, num_bytes, parent,
1909                                            root_objectid, owner, offset, 1);
1910         if (ret == 0) {
1911                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1912                 update_inline_extent_backref(root, path, iref,
1913                                              refs_to_add, extent_op, NULL);
1914         } else if (ret == -ENOENT) {
1915                 setup_inline_extent_backref(root, path, iref, parent,
1916                                             root_objectid, owner, offset,
1917                                             refs_to_add, extent_op);
1918                 ret = 0;
1919         }
1920         return ret;
1921 }
1922
1923 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1924                                  struct btrfs_root *root,
1925                                  struct btrfs_path *path,
1926                                  u64 bytenr, u64 parent, u64 root_objectid,
1927                                  u64 owner, u64 offset, int refs_to_add)
1928 {
1929         int ret;
1930         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1931                 BUG_ON(refs_to_add != 1);
1932                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1933                                             parent, root_objectid);
1934         } else {
1935                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1936                                              parent, root_objectid,
1937                                              owner, offset, refs_to_add);
1938         }
1939         return ret;
1940 }
1941
1942 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1943                                  struct btrfs_root *root,
1944                                  struct btrfs_path *path,
1945                                  struct btrfs_extent_inline_ref *iref,
1946                                  int refs_to_drop, int is_data, int *last_ref)
1947 {
1948         int ret = 0;
1949
1950         BUG_ON(!is_data && refs_to_drop != 1);
1951         if (iref) {
1952                 update_inline_extent_backref(root, path, iref,
1953                                              -refs_to_drop, NULL, last_ref);
1954         } else if (is_data) {
1955                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1956                                              last_ref);
1957         } else {
1958                 *last_ref = 1;
1959                 ret = btrfs_del_item(trans, root, path);
1960         }
1961         return ret;
1962 }
1963
1964 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1965 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1966                                u64 *discarded_bytes)
1967 {
1968         int j, ret = 0;
1969         u64 bytes_left, end;
1970         u64 aligned_start = ALIGN(start, 1 << 9);
1971
1972         if (WARN_ON(start != aligned_start)) {
1973                 len -= aligned_start - start;
1974                 len = round_down(len, 1 << 9);
1975                 start = aligned_start;
1976         }
1977
1978         *discarded_bytes = 0;
1979
1980         if (!len)
1981                 return 0;
1982
1983         end = start + len;
1984         bytes_left = len;
1985
1986         /* Skip any superblocks on this device. */
1987         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1988                 u64 sb_start = btrfs_sb_offset(j);
1989                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1990                 u64 size = sb_start - start;
1991
1992                 if (!in_range(sb_start, start, bytes_left) &&
1993                     !in_range(sb_end, start, bytes_left) &&
1994                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1995                         continue;
1996
1997                 /*
1998                  * Superblock spans beginning of range.  Adjust start and
1999                  * try again.
2000                  */
2001                 if (sb_start <= start) {
2002                         start += sb_end - start;
2003                         if (start > end) {
2004                                 bytes_left = 0;
2005                                 break;
2006                         }
2007                         bytes_left = end - start;
2008                         continue;
2009                 }
2010
2011                 if (size) {
2012                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2013                                                    GFP_NOFS, 0);
2014                         if (!ret)
2015                                 *discarded_bytes += size;
2016                         else if (ret != -EOPNOTSUPP)
2017                                 return ret;
2018                 }
2019
2020                 start = sb_end;
2021                 if (start > end) {
2022                         bytes_left = 0;
2023                         break;
2024                 }
2025                 bytes_left = end - start;
2026         }
2027
2028         if (bytes_left) {
2029                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2030                                            GFP_NOFS, 0);
2031                 if (!ret)
2032                         *discarded_bytes += bytes_left;
2033         }
2034         return ret;
2035 }
2036
2037 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
2038                          u64 num_bytes, u64 *actual_bytes)
2039 {
2040         int ret;
2041         u64 discarded_bytes = 0;
2042         struct btrfs_bio *bbio = NULL;
2043
2044
2045         /* Tell the block device(s) that the sectors can be discarded */
2046         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
2047                               bytenr, &num_bytes, &bbio, 0);
2048         /* Error condition is -ENOMEM */
2049         if (!ret) {
2050                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2051                 int i;
2052
2053
2054                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2055                         u64 bytes;
2056                         if (!stripe->dev->can_discard)
2057                                 continue;
2058
2059                         ret = btrfs_issue_discard(stripe->dev->bdev,
2060                                                   stripe->physical,
2061                                                   stripe->length,
2062                                                   &bytes);
2063                         if (!ret)
2064                                 discarded_bytes += bytes;
2065                         else if (ret != -EOPNOTSUPP)
2066                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2067
2068                         /*
2069                          * Just in case we get back EOPNOTSUPP for some reason,
2070                          * just ignore the return value so we don't screw up
2071                          * people calling discard_extent.
2072                          */
2073                         ret = 0;
2074                 }
2075                 btrfs_put_bbio(bbio);
2076         }
2077
2078         if (actual_bytes)
2079                 *actual_bytes = discarded_bytes;
2080
2081
2082         if (ret == -EOPNOTSUPP)
2083                 ret = 0;
2084         return ret;
2085 }
2086
2087 /* Can return -ENOMEM */
2088 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2089                          struct btrfs_root *root,
2090                          u64 bytenr, u64 num_bytes, u64 parent,
2091                          u64 root_objectid, u64 owner, u64 offset)
2092 {
2093         int ret;
2094         struct btrfs_fs_info *fs_info = root->fs_info;
2095
2096         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2097                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2098
2099         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2100                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2101                                         num_bytes,
2102                                         parent, root_objectid, (int)owner,
2103                                         BTRFS_ADD_DELAYED_REF, NULL);
2104         } else {
2105                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2106                                         num_bytes, parent, root_objectid,
2107                                         owner, offset, 0,
2108                                         BTRFS_ADD_DELAYED_REF, NULL);
2109         }
2110         return ret;
2111 }
2112
2113 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2114                                   struct btrfs_root *root,
2115                                   struct btrfs_delayed_ref_node *node,
2116                                   u64 parent, u64 root_objectid,
2117                                   u64 owner, u64 offset, int refs_to_add,
2118                                   struct btrfs_delayed_extent_op *extent_op)
2119 {
2120         struct btrfs_fs_info *fs_info = root->fs_info;
2121         struct btrfs_path *path;
2122         struct extent_buffer *leaf;
2123         struct btrfs_extent_item *item;
2124         struct btrfs_key key;
2125         u64 bytenr = node->bytenr;
2126         u64 num_bytes = node->num_bytes;
2127         u64 refs;
2128         int ret;
2129
2130         path = btrfs_alloc_path();
2131         if (!path)
2132                 return -ENOMEM;
2133
2134         path->reada = READA_FORWARD;
2135         path->leave_spinning = 1;
2136         /* this will setup the path even if it fails to insert the back ref */
2137         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2138                                            bytenr, num_bytes, parent,
2139                                            root_objectid, owner, offset,
2140                                            refs_to_add, extent_op);
2141         if ((ret < 0 && ret != -EAGAIN) || !ret)
2142                 goto out;
2143
2144         /*
2145          * Ok we had -EAGAIN which means we didn't have space to insert and
2146          * inline extent ref, so just update the reference count and add a
2147          * normal backref.
2148          */
2149         leaf = path->nodes[0];
2150         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2151         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2152         refs = btrfs_extent_refs(leaf, item);
2153         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2154         if (extent_op)
2155                 __run_delayed_extent_op(extent_op, leaf, item);
2156
2157         btrfs_mark_buffer_dirty(leaf);
2158         btrfs_release_path(path);
2159
2160         path->reada = READA_FORWARD;
2161         path->leave_spinning = 1;
2162         /* now insert the actual backref */
2163         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2164                                     path, bytenr, parent, root_objectid,
2165                                     owner, offset, refs_to_add);
2166         if (ret)
2167                 btrfs_abort_transaction(trans, root, ret);
2168 out:
2169         btrfs_free_path(path);
2170         return ret;
2171 }
2172
2173 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2174                                 struct btrfs_root *root,
2175                                 struct btrfs_delayed_ref_node *node,
2176                                 struct btrfs_delayed_extent_op *extent_op,
2177                                 int insert_reserved)
2178 {
2179         int ret = 0;
2180         struct btrfs_delayed_data_ref *ref;
2181         struct btrfs_key ins;
2182         u64 parent = 0;
2183         u64 ref_root = 0;
2184         u64 flags = 0;
2185
2186         ins.objectid = node->bytenr;
2187         ins.offset = node->num_bytes;
2188         ins.type = BTRFS_EXTENT_ITEM_KEY;
2189
2190         ref = btrfs_delayed_node_to_data_ref(node);
2191         trace_run_delayed_data_ref(node, ref, node->action);
2192
2193         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2194                 parent = ref->parent;
2195         ref_root = ref->root;
2196
2197         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2198                 if (extent_op)
2199                         flags |= extent_op->flags_to_set;
2200                 ret = alloc_reserved_file_extent(trans, root,
2201                                                  parent, ref_root, flags,
2202                                                  ref->objectid, ref->offset,
2203                                                  &ins, node->ref_mod);
2204         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2205                 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2206                                              ref_root, ref->objectid,
2207                                              ref->offset, node->ref_mod,
2208                                              extent_op);
2209         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2210                 ret = __btrfs_free_extent(trans, root, node, parent,
2211                                           ref_root, ref->objectid,
2212                                           ref->offset, node->ref_mod,
2213                                           extent_op);
2214         } else {
2215                 BUG();
2216         }
2217         return ret;
2218 }
2219
2220 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2221                                     struct extent_buffer *leaf,
2222                                     struct btrfs_extent_item *ei)
2223 {
2224         u64 flags = btrfs_extent_flags(leaf, ei);
2225         if (extent_op->update_flags) {
2226                 flags |= extent_op->flags_to_set;
2227                 btrfs_set_extent_flags(leaf, ei, flags);
2228         }
2229
2230         if (extent_op->update_key) {
2231                 struct btrfs_tree_block_info *bi;
2232                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2233                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2234                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2235         }
2236 }
2237
2238 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2239                                  struct btrfs_root *root,
2240                                  struct btrfs_delayed_ref_node *node,
2241                                  struct btrfs_delayed_extent_op *extent_op)
2242 {
2243         struct btrfs_key key;
2244         struct btrfs_path *path;
2245         struct btrfs_extent_item *ei;
2246         struct extent_buffer *leaf;
2247         u32 item_size;
2248         int ret;
2249         int err = 0;
2250         int metadata = !extent_op->is_data;
2251
2252         if (trans->aborted)
2253                 return 0;
2254
2255         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2256                 metadata = 0;
2257
2258         path = btrfs_alloc_path();
2259         if (!path)
2260                 return -ENOMEM;
2261
2262         key.objectid = node->bytenr;
2263
2264         if (metadata) {
2265                 key.type = BTRFS_METADATA_ITEM_KEY;
2266                 key.offset = extent_op->level;
2267         } else {
2268                 key.type = BTRFS_EXTENT_ITEM_KEY;
2269                 key.offset = node->num_bytes;
2270         }
2271
2272 again:
2273         path->reada = READA_FORWARD;
2274         path->leave_spinning = 1;
2275         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2276                                 path, 0, 1);
2277         if (ret < 0) {
2278                 err = ret;
2279                 goto out;
2280         }
2281         if (ret > 0) {
2282                 if (metadata) {
2283                         if (path->slots[0] > 0) {
2284                                 path->slots[0]--;
2285                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2286                                                       path->slots[0]);
2287                                 if (key.objectid == node->bytenr &&
2288                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2289                                     key.offset == node->num_bytes)
2290                                         ret = 0;
2291                         }
2292                         if (ret > 0) {
2293                                 btrfs_release_path(path);
2294                                 metadata = 0;
2295
2296                                 key.objectid = node->bytenr;
2297                                 key.offset = node->num_bytes;
2298                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2299                                 goto again;
2300                         }
2301                 } else {
2302                         err = -EIO;
2303                         goto out;
2304                 }
2305         }
2306
2307         leaf = path->nodes[0];
2308         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2309 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2310         if (item_size < sizeof(*ei)) {
2311                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2312                                              path, (u64)-1, 0);
2313                 if (ret < 0) {
2314                         err = ret;
2315                         goto out;
2316                 }
2317                 leaf = path->nodes[0];
2318                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2319         }
2320 #endif
2321         BUG_ON(item_size < sizeof(*ei));
2322         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2323         __run_delayed_extent_op(extent_op, leaf, ei);
2324
2325         btrfs_mark_buffer_dirty(leaf);
2326 out:
2327         btrfs_free_path(path);
2328         return err;
2329 }
2330
2331 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2332                                 struct btrfs_root *root,
2333                                 struct btrfs_delayed_ref_node *node,
2334                                 struct btrfs_delayed_extent_op *extent_op,
2335                                 int insert_reserved)
2336 {
2337         int ret = 0;
2338         struct btrfs_delayed_tree_ref *ref;
2339         struct btrfs_key ins;
2340         u64 parent = 0;
2341         u64 ref_root = 0;
2342         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2343                                                  SKINNY_METADATA);
2344
2345         ref = btrfs_delayed_node_to_tree_ref(node);
2346         trace_run_delayed_tree_ref(node, ref, node->action);
2347
2348         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2349                 parent = ref->parent;
2350         ref_root = ref->root;
2351
2352         ins.objectid = node->bytenr;
2353         if (skinny_metadata) {
2354                 ins.offset = ref->level;
2355                 ins.type = BTRFS_METADATA_ITEM_KEY;
2356         } else {
2357                 ins.offset = node->num_bytes;
2358                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2359         }
2360
2361         BUG_ON(node->ref_mod != 1);
2362         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2363                 BUG_ON(!extent_op || !extent_op->update_flags);
2364                 ret = alloc_reserved_tree_block(trans, root,
2365                                                 parent, ref_root,
2366                                                 extent_op->flags_to_set,
2367                                                 &extent_op->key,
2368                                                 ref->level, &ins);
2369         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2370                 ret = __btrfs_inc_extent_ref(trans, root, node,
2371                                              parent, ref_root,
2372                                              ref->level, 0, 1,
2373                                              extent_op);
2374         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2375                 ret = __btrfs_free_extent(trans, root, node,
2376                                           parent, ref_root,
2377                                           ref->level, 0, 1, extent_op);
2378         } else {
2379                 BUG();
2380         }
2381         return ret;
2382 }
2383
2384 /* helper function to actually process a single delayed ref entry */
2385 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2386                                struct btrfs_root *root,
2387                                struct btrfs_delayed_ref_node *node,
2388                                struct btrfs_delayed_extent_op *extent_op,
2389                                int insert_reserved)
2390 {
2391         int ret = 0;
2392
2393         if (trans->aborted) {
2394                 if (insert_reserved)
2395                         btrfs_pin_extent(root, node->bytenr,
2396                                          node->num_bytes, 1);
2397                 return 0;
2398         }
2399
2400         if (btrfs_delayed_ref_is_head(node)) {
2401                 struct btrfs_delayed_ref_head *head;
2402                 /*
2403                  * we've hit the end of the chain and we were supposed
2404                  * to insert this extent into the tree.  But, it got
2405                  * deleted before we ever needed to insert it, so all
2406                  * we have to do is clean up the accounting
2407                  */
2408                 BUG_ON(extent_op);
2409                 head = btrfs_delayed_node_to_head(node);
2410                 trace_run_delayed_ref_head(node, head, node->action);
2411
2412                 if (insert_reserved) {
2413                         btrfs_pin_extent(root, node->bytenr,
2414                                          node->num_bytes, 1);
2415                         if (head->is_data) {
2416                                 ret = btrfs_del_csums(trans, root,
2417                                                       node->bytenr,
2418                                                       node->num_bytes);
2419                         }
2420                 }
2421
2422                 /* Also free its reserved qgroup space */
2423                 btrfs_qgroup_free_delayed_ref(root->fs_info,
2424                                               head->qgroup_ref_root,
2425                                               head->qgroup_reserved);
2426                 return ret;
2427         }
2428
2429         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2430             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2431                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2432                                            insert_reserved);
2433         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2434                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2435                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2436                                            insert_reserved);
2437         else
2438                 BUG();
2439         return ret;
2440 }
2441
2442 static inline struct btrfs_delayed_ref_node *
2443 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2444 {
2445         struct btrfs_delayed_ref_node *ref;
2446
2447         if (list_empty(&head->ref_list))
2448                 return NULL;
2449
2450         /*
2451          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2452          * This is to prevent a ref count from going down to zero, which deletes
2453          * the extent item from the extent tree, when there still are references
2454          * to add, which would fail because they would not find the extent item.
2455          */
2456         list_for_each_entry(ref, &head->ref_list, list) {
2457                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2458                         return ref;
2459         }
2460
2461         return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2462                           list);
2463 }
2464
2465 /*
2466  * Returns 0 on success or if called with an already aborted transaction.
2467  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2468  */
2469 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2470                                              struct btrfs_root *root,
2471                                              unsigned long nr)
2472 {
2473         struct btrfs_delayed_ref_root *delayed_refs;
2474         struct btrfs_delayed_ref_node *ref;
2475         struct btrfs_delayed_ref_head *locked_ref = NULL;
2476         struct btrfs_delayed_extent_op *extent_op;
2477         struct btrfs_fs_info *fs_info = root->fs_info;
2478         ktime_t start = ktime_get();
2479         int ret;
2480         unsigned long count = 0;
2481         unsigned long actual_count = 0;
2482         int must_insert_reserved = 0;
2483
2484         delayed_refs = &trans->transaction->delayed_refs;
2485         while (1) {
2486                 if (!locked_ref) {
2487                         if (count >= nr)
2488                                 break;
2489
2490                         spin_lock(&delayed_refs->lock);
2491                         locked_ref = btrfs_select_ref_head(trans);
2492                         if (!locked_ref) {
2493                                 spin_unlock(&delayed_refs->lock);
2494                                 break;
2495                         }
2496
2497                         /* grab the lock that says we are going to process
2498                          * all the refs for this head */
2499                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2500                         spin_unlock(&delayed_refs->lock);
2501                         /*
2502                          * we may have dropped the spin lock to get the head
2503                          * mutex lock, and that might have given someone else
2504                          * time to free the head.  If that's true, it has been
2505                          * removed from our list and we can move on.
2506                          */
2507                         if (ret == -EAGAIN) {
2508                                 locked_ref = NULL;
2509                                 count++;
2510                                 continue;
2511                         }
2512                 }
2513
2514                 /*
2515                  * We need to try and merge add/drops of the same ref since we
2516                  * can run into issues with relocate dropping the implicit ref
2517                  * and then it being added back again before the drop can
2518                  * finish.  If we merged anything we need to re-loop so we can
2519                  * get a good ref.
2520                  * Or we can get node references of the same type that weren't
2521                  * merged when created due to bumps in the tree mod seq, and
2522                  * we need to merge them to prevent adding an inline extent
2523                  * backref before dropping it (triggering a BUG_ON at
2524                  * insert_inline_extent_backref()).
2525                  */
2526                 spin_lock(&locked_ref->lock);
2527                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2528                                          locked_ref);
2529
2530                 /*
2531                  * locked_ref is the head node, so we have to go one
2532                  * node back for any delayed ref updates
2533                  */
2534                 ref = select_delayed_ref(locked_ref);
2535
2536                 if (ref && ref->seq &&
2537                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2538                         spin_unlock(&locked_ref->lock);
2539                         btrfs_delayed_ref_unlock(locked_ref);
2540                         spin_lock(&delayed_refs->lock);
2541                         locked_ref->processing = 0;
2542                         delayed_refs->num_heads_ready++;
2543                         spin_unlock(&delayed_refs->lock);
2544                         locked_ref = NULL;
2545                         cond_resched();
2546                         count++;
2547                         continue;
2548                 }
2549
2550                 /*
2551                  * record the must insert reserved flag before we
2552                  * drop the spin lock.
2553                  */
2554                 must_insert_reserved = locked_ref->must_insert_reserved;
2555                 locked_ref->must_insert_reserved = 0;
2556
2557                 extent_op = locked_ref->extent_op;
2558                 locked_ref->extent_op = NULL;
2559
2560                 if (!ref) {
2561
2562
2563                         /* All delayed refs have been processed, Go ahead
2564                          * and send the head node to run_one_delayed_ref,
2565                          * so that any accounting fixes can happen
2566                          */
2567                         ref = &locked_ref->node;
2568
2569                         if (extent_op && must_insert_reserved) {
2570                                 btrfs_free_delayed_extent_op(extent_op);
2571                                 extent_op = NULL;
2572                         }
2573
2574                         if (extent_op) {
2575                                 spin_unlock(&locked_ref->lock);
2576                                 ret = run_delayed_extent_op(trans, root,
2577                                                             ref, extent_op);
2578                                 btrfs_free_delayed_extent_op(extent_op);
2579
2580                                 if (ret) {
2581                                         /*
2582                                          * Need to reset must_insert_reserved if
2583                                          * there was an error so the abort stuff
2584                                          * can cleanup the reserved space
2585                                          * properly.
2586                                          */
2587                                         if (must_insert_reserved)
2588                                                 locked_ref->must_insert_reserved = 1;
2589                                         locked_ref->processing = 0;
2590                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2591                                         btrfs_delayed_ref_unlock(locked_ref);
2592                                         return ret;
2593                                 }
2594                                 continue;
2595                         }
2596
2597                         /*
2598                          * Need to drop our head ref lock and re-aqcuire the
2599                          * delayed ref lock and then re-check to make sure
2600                          * nobody got added.
2601                          */
2602                         spin_unlock(&locked_ref->lock);
2603                         spin_lock(&delayed_refs->lock);
2604                         spin_lock(&locked_ref->lock);
2605                         if (!list_empty(&locked_ref->ref_list) ||
2606                             locked_ref->extent_op) {
2607                                 spin_unlock(&locked_ref->lock);
2608                                 spin_unlock(&delayed_refs->lock);
2609                                 continue;
2610                         }
2611                         ref->in_tree = 0;
2612                         delayed_refs->num_heads--;
2613                         rb_erase(&locked_ref->href_node,
2614                                  &delayed_refs->href_root);
2615                         spin_unlock(&delayed_refs->lock);
2616                 } else {
2617                         actual_count++;
2618                         ref->in_tree = 0;
2619                         list_del(&ref->list);
2620                 }
2621                 atomic_dec(&delayed_refs->num_entries);
2622
2623                 if (!btrfs_delayed_ref_is_head(ref)) {
2624                         /*
2625                          * when we play the delayed ref, also correct the
2626                          * ref_mod on head
2627                          */
2628                         switch (ref->action) {
2629                         case BTRFS_ADD_DELAYED_REF:
2630                         case BTRFS_ADD_DELAYED_EXTENT:
2631                                 locked_ref->node.ref_mod -= ref->ref_mod;
2632                                 break;
2633                         case BTRFS_DROP_DELAYED_REF:
2634                                 locked_ref->node.ref_mod += ref->ref_mod;
2635                                 break;
2636                         default:
2637                                 WARN_ON(1);
2638                         }
2639                 }
2640                 spin_unlock(&locked_ref->lock);
2641
2642                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2643                                           must_insert_reserved);
2644
2645                 btrfs_free_delayed_extent_op(extent_op);
2646                 if (ret) {
2647                         locked_ref->processing = 0;
2648                         btrfs_delayed_ref_unlock(locked_ref);
2649                         btrfs_put_delayed_ref(ref);
2650                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2651                         return ret;
2652                 }
2653
2654                 /*
2655                  * If this node is a head, that means all the refs in this head
2656                  * have been dealt with, and we will pick the next head to deal
2657                  * with, so we must unlock the head and drop it from the cluster
2658                  * list before we release it.
2659                  */
2660                 if (btrfs_delayed_ref_is_head(ref)) {
2661                         if (locked_ref->is_data &&
2662                             locked_ref->total_ref_mod < 0) {
2663                                 spin_lock(&delayed_refs->lock);
2664                                 delayed_refs->pending_csums -= ref->num_bytes;
2665                                 spin_unlock(&delayed_refs->lock);
2666                         }
2667                         btrfs_delayed_ref_unlock(locked_ref);
2668                         locked_ref = NULL;
2669                 }
2670                 btrfs_put_delayed_ref(ref);
2671                 count++;
2672                 cond_resched();
2673         }
2674
2675         /*
2676          * We don't want to include ref heads since we can have empty ref heads
2677          * and those will drastically skew our runtime down since we just do
2678          * accounting, no actual extent tree updates.
2679          */
2680         if (actual_count > 0) {
2681                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2682                 u64 avg;
2683
2684                 /*
2685                  * We weigh the current average higher than our current runtime
2686                  * to avoid large swings in the average.
2687                  */
2688                 spin_lock(&delayed_refs->lock);
2689                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2690                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2691                 spin_unlock(&delayed_refs->lock);
2692         }
2693         return 0;
2694 }
2695
2696 #ifdef SCRAMBLE_DELAYED_REFS
2697 /*
2698  * Normally delayed refs get processed in ascending bytenr order. This
2699  * correlates in most cases to the order added. To expose dependencies on this
2700  * order, we start to process the tree in the middle instead of the beginning
2701  */
2702 static u64 find_middle(struct rb_root *root)
2703 {
2704         struct rb_node *n = root->rb_node;
2705         struct btrfs_delayed_ref_node *entry;
2706         int alt = 1;
2707         u64 middle;
2708         u64 first = 0, last = 0;
2709
2710         n = rb_first(root);
2711         if (n) {
2712                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2713                 first = entry->bytenr;
2714         }
2715         n = rb_last(root);
2716         if (n) {
2717                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2718                 last = entry->bytenr;
2719         }
2720         n = root->rb_node;
2721
2722         while (n) {
2723                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2724                 WARN_ON(!entry->in_tree);
2725
2726                 middle = entry->bytenr;
2727
2728                 if (alt)
2729                         n = n->rb_left;
2730                 else
2731                         n = n->rb_right;
2732
2733                 alt = 1 - alt;
2734         }
2735         return middle;
2736 }
2737 #endif
2738
2739 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2740 {
2741         u64 num_bytes;
2742
2743         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2744                              sizeof(struct btrfs_extent_inline_ref));
2745         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2746                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2747
2748         /*
2749          * We don't ever fill up leaves all the way so multiply by 2 just to be
2750          * closer to what we're really going to want to ouse.
2751          */
2752         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2753 }
2754
2755 /*
2756  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2757  * would require to store the csums for that many bytes.
2758  */
2759 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2760 {
2761         u64 csum_size;
2762         u64 num_csums_per_leaf;
2763         u64 num_csums;
2764
2765         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
2766         num_csums_per_leaf = div64_u64(csum_size,
2767                         (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2768         num_csums = div64_u64(csum_bytes, root->sectorsize);
2769         num_csums += num_csums_per_leaf - 1;
2770         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2771         return num_csums;
2772 }
2773
2774 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2775                                        struct btrfs_root *root)
2776 {
2777         struct btrfs_block_rsv *global_rsv;
2778         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2779         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2780         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2781         u64 num_bytes, num_dirty_bgs_bytes;
2782         int ret = 0;
2783
2784         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2785         num_heads = heads_to_leaves(root, num_heads);
2786         if (num_heads > 1)
2787                 num_bytes += (num_heads - 1) * root->nodesize;
2788         num_bytes <<= 1;
2789         num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2790         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2791                                                              num_dirty_bgs);
2792         global_rsv = &root->fs_info->global_block_rsv;
2793
2794         /*
2795          * If we can't allocate any more chunks lets make sure we have _lots_ of
2796          * wiggle room since running delayed refs can create more delayed refs.
2797          */
2798         if (global_rsv->space_info->full) {
2799                 num_dirty_bgs_bytes <<= 1;
2800                 num_bytes <<= 1;
2801         }
2802
2803         spin_lock(&global_rsv->lock);
2804         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2805                 ret = 1;
2806         spin_unlock(&global_rsv->lock);
2807         return ret;
2808 }
2809
2810 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2811                                        struct btrfs_root *root)
2812 {
2813         struct btrfs_fs_info *fs_info = root->fs_info;
2814         u64 num_entries =
2815                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2816         u64 avg_runtime;
2817         u64 val;
2818
2819         smp_mb();
2820         avg_runtime = fs_info->avg_delayed_ref_runtime;
2821         val = num_entries * avg_runtime;
2822         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2823                 return 1;
2824         if (val >= NSEC_PER_SEC / 2)
2825                 return 2;
2826
2827         return btrfs_check_space_for_delayed_refs(trans, root);
2828 }
2829
2830 struct async_delayed_refs {
2831         struct btrfs_root *root;
2832         int count;
2833         int error;
2834         int sync;
2835         struct completion wait;
2836         struct btrfs_work work;
2837 };
2838
2839 static void delayed_ref_async_start(struct btrfs_work *work)
2840 {
2841         struct async_delayed_refs *async;
2842         struct btrfs_trans_handle *trans;
2843         int ret;
2844
2845         async = container_of(work, struct async_delayed_refs, work);
2846
2847         trans = btrfs_join_transaction(async->root);
2848         if (IS_ERR(trans)) {
2849                 async->error = PTR_ERR(trans);
2850                 goto done;
2851         }
2852
2853         /*
2854          * trans->sync means that when we call end_transaciton, we won't
2855          * wait on delayed refs
2856          */
2857         trans->sync = true;
2858         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2859         if (ret)
2860                 async->error = ret;
2861
2862         ret = btrfs_end_transaction(trans, async->root);
2863         if (ret && !async->error)
2864                 async->error = ret;
2865 done:
2866         if (async->sync)
2867                 complete(&async->wait);
2868         else
2869                 kfree(async);
2870 }
2871
2872 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2873                                  unsigned long count, int wait)
2874 {
2875         struct async_delayed_refs *async;
2876         int ret;
2877
2878         async = kmalloc(sizeof(*async), GFP_NOFS);
2879         if (!async)
2880                 return -ENOMEM;
2881
2882         async->root = root->fs_info->tree_root;
2883         async->count = count;
2884         async->error = 0;
2885         if (wait)
2886                 async->sync = 1;
2887         else
2888                 async->sync = 0;
2889         init_completion(&async->wait);
2890
2891         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2892                         delayed_ref_async_start, NULL, NULL);
2893
2894         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2895
2896         if (wait) {
2897                 wait_for_completion(&async->wait);
2898                 ret = async->error;
2899                 kfree(async);
2900                 return ret;
2901         }
2902         return 0;
2903 }
2904
2905 /*
2906  * this starts processing the delayed reference count updates and
2907  * extent insertions we have queued up so far.  count can be
2908  * 0, which means to process everything in the tree at the start
2909  * of the run (but not newly added entries), or it can be some target
2910  * number you'd like to process.
2911  *
2912  * Returns 0 on success or if called with an aborted transaction
2913  * Returns <0 on error and aborts the transaction
2914  */
2915 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2916                            struct btrfs_root *root, unsigned long count)
2917 {
2918         struct rb_node *node;
2919         struct btrfs_delayed_ref_root *delayed_refs;
2920         struct btrfs_delayed_ref_head *head;
2921         int ret;
2922         int run_all = count == (unsigned long)-1;
2923         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2924
2925         /* We'll clean this up in btrfs_cleanup_transaction */
2926         if (trans->aborted)
2927                 return 0;
2928
2929         if (root->fs_info->creating_free_space_tree)
2930                 return 0;
2931
2932         if (root == root->fs_info->extent_root)
2933                 root = root->fs_info->tree_root;
2934
2935         delayed_refs = &trans->transaction->delayed_refs;
2936         if (count == 0)
2937                 count = atomic_read(&delayed_refs->num_entries) * 2;
2938
2939 again:
2940 #ifdef SCRAMBLE_DELAYED_REFS
2941         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2942 #endif
2943         trans->can_flush_pending_bgs = false;
2944         ret = __btrfs_run_delayed_refs(trans, root, count);
2945         if (ret < 0) {
2946                 btrfs_abort_transaction(trans, root, ret);
2947                 return ret;
2948         }
2949
2950         if (run_all) {
2951                 if (!list_empty(&trans->new_bgs))
2952                         btrfs_create_pending_block_groups(trans, root);
2953
2954                 spin_lock(&delayed_refs->lock);
2955                 node = rb_first(&delayed_refs->href_root);
2956                 if (!node) {
2957                         spin_unlock(&delayed_refs->lock);
2958                         goto out;
2959                 }
2960                 count = (unsigned long)-1;
2961
2962                 while (node) {
2963                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2964                                         href_node);
2965                         if (btrfs_delayed_ref_is_head(&head->node)) {
2966                                 struct btrfs_delayed_ref_node *ref;
2967
2968                                 ref = &head->node;
2969                                 atomic_inc(&ref->refs);
2970
2971                                 spin_unlock(&delayed_refs->lock);
2972                                 /*
2973                                  * Mutex was contended, block until it's
2974                                  * released and try again
2975                                  */
2976                                 mutex_lock(&head->mutex);
2977                                 mutex_unlock(&head->mutex);
2978
2979                                 btrfs_put_delayed_ref(ref);
2980                                 cond_resched();
2981                                 goto again;
2982                         } else {
2983                                 WARN_ON(1);
2984                         }
2985                         node = rb_next(node);
2986                 }
2987                 spin_unlock(&delayed_refs->lock);
2988                 cond_resched();
2989                 goto again;
2990         }
2991 out:
2992         assert_qgroups_uptodate(trans);
2993         trans->can_flush_pending_bgs = can_flush_pending_bgs;
2994         return 0;
2995 }
2996
2997 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2998                                 struct btrfs_root *root,
2999                                 u64 bytenr, u64 num_bytes, u64 flags,
3000                                 int level, int is_data)
3001 {
3002         struct btrfs_delayed_extent_op *extent_op;
3003         int ret;
3004
3005         extent_op = btrfs_alloc_delayed_extent_op();
3006         if (!extent_op)
3007                 return -ENOMEM;
3008
3009         extent_op->flags_to_set = flags;
3010         extent_op->update_flags = true;
3011         extent_op->update_key = false;
3012         extent_op->is_data = is_data ? true : false;
3013         extent_op->level = level;
3014
3015         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
3016                                           num_bytes, extent_op);
3017         if (ret)
3018                 btrfs_free_delayed_extent_op(extent_op);
3019         return ret;
3020 }
3021
3022 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
3023                                       struct btrfs_root *root,
3024                                       struct btrfs_path *path,
3025                                       u64 objectid, u64 offset, u64 bytenr)
3026 {
3027         struct btrfs_delayed_ref_head *head;
3028         struct btrfs_delayed_ref_node *ref;
3029         struct btrfs_delayed_data_ref *data_ref;
3030         struct btrfs_delayed_ref_root *delayed_refs;
3031         int ret = 0;
3032
3033         delayed_refs = &trans->transaction->delayed_refs;
3034         spin_lock(&delayed_refs->lock);
3035         head = btrfs_find_delayed_ref_head(trans, bytenr);
3036         if (!head) {
3037                 spin_unlock(&delayed_refs->lock);
3038                 return 0;
3039         }
3040
3041         if (!mutex_trylock(&head->mutex)) {
3042                 atomic_inc(&head->node.refs);
3043                 spin_unlock(&delayed_refs->lock);
3044
3045                 btrfs_release_path(path);
3046
3047                 /*
3048                  * Mutex was contended, block until it's released and let
3049                  * caller try again
3050                  */
3051                 mutex_lock(&head->mutex);
3052                 mutex_unlock(&head->mutex);
3053                 btrfs_put_delayed_ref(&head->node);
3054                 return -EAGAIN;
3055         }
3056         spin_unlock(&delayed_refs->lock);
3057
3058         spin_lock(&head->lock);
3059         list_for_each_entry(ref, &head->ref_list, list) {
3060                 /* If it's a shared ref we know a cross reference exists */
3061                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3062                         ret = 1;
3063                         break;
3064                 }
3065
3066                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3067
3068                 /*
3069                  * If our ref doesn't match the one we're currently looking at
3070                  * then we have a cross reference.
3071                  */
3072                 if (data_ref->root != root->root_key.objectid ||
3073                     data_ref->objectid != objectid ||
3074                     data_ref->offset != offset) {
3075                         ret = 1;
3076                         break;
3077                 }
3078         }
3079         spin_unlock(&head->lock);
3080         mutex_unlock(&head->mutex);
3081         return ret;
3082 }
3083
3084 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
3085                                         struct btrfs_root *root,
3086                                         struct btrfs_path *path,
3087                                         u64 objectid, u64 offset, u64 bytenr)
3088 {
3089         struct btrfs_root *extent_root = root->fs_info->extent_root;
3090         struct extent_buffer *leaf;
3091         struct btrfs_extent_data_ref *ref;
3092         struct btrfs_extent_inline_ref *iref;
3093         struct btrfs_extent_item *ei;
3094         struct btrfs_key key;
3095         u32 item_size;
3096         int ret;
3097
3098         key.objectid = bytenr;
3099         key.offset = (u64)-1;
3100         key.type = BTRFS_EXTENT_ITEM_KEY;
3101
3102         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3103         if (ret < 0)
3104                 goto out;
3105         BUG_ON(ret == 0); /* Corruption */
3106
3107         ret = -ENOENT;
3108         if (path->slots[0] == 0)
3109                 goto out;
3110
3111         path->slots[0]--;
3112         leaf = path->nodes[0];
3113         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3114
3115         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3116                 goto out;
3117
3118         ret = 1;
3119         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3120 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3121         if (item_size < sizeof(*ei)) {
3122                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3123                 goto out;
3124         }
3125 #endif
3126         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3127
3128         if (item_size != sizeof(*ei) +
3129             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3130                 goto out;
3131
3132         if (btrfs_extent_generation(leaf, ei) <=
3133             btrfs_root_last_snapshot(&root->root_item))
3134                 goto out;
3135
3136         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3137         if (btrfs_extent_inline_ref_type(leaf, iref) !=
3138             BTRFS_EXTENT_DATA_REF_KEY)
3139                 goto out;
3140
3141         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3142         if (btrfs_extent_refs(leaf, ei) !=
3143             btrfs_extent_data_ref_count(leaf, ref) ||
3144             btrfs_extent_data_ref_root(leaf, ref) !=
3145             root->root_key.objectid ||
3146             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3147             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3148                 goto out;
3149
3150         ret = 0;
3151 out:
3152         return ret;
3153 }
3154
3155 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3156                           struct btrfs_root *root,
3157                           u64 objectid, u64 offset, u64 bytenr)
3158 {
3159         struct btrfs_path *path;
3160         int ret;
3161         int ret2;
3162
3163         path = btrfs_alloc_path();
3164         if (!path)
3165                 return -ENOENT;
3166
3167         do {
3168                 ret = check_committed_ref(trans, root, path, objectid,
3169                                           offset, bytenr);
3170                 if (ret && ret != -ENOENT)
3171                         goto out;
3172
3173                 ret2 = check_delayed_ref(trans, root, path, objectid,
3174                                          offset, bytenr);
3175         } while (ret2 == -EAGAIN);
3176
3177         if (ret2 && ret2 != -ENOENT) {
3178                 ret = ret2;
3179                 goto out;
3180         }
3181
3182         if (ret != -ENOENT || ret2 != -ENOENT)
3183                 ret = 0;
3184 out:
3185         btrfs_free_path(path);
3186         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3187                 WARN_ON(ret > 0);
3188         return ret;
3189 }
3190
3191 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3192                            struct btrfs_root *root,
3193                            struct extent_buffer *buf,
3194                            int full_backref, int inc)
3195 {
3196         u64 bytenr;
3197         u64 num_bytes;
3198         u64 parent;
3199         u64 ref_root;
3200         u32 nritems;
3201         struct btrfs_key key;
3202         struct btrfs_file_extent_item *fi;
3203         int i;
3204         int level;
3205         int ret = 0;
3206         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3207                             u64, u64, u64, u64, u64, u64);
3208
3209
3210         if (btrfs_test_is_dummy_root(root))
3211                 return 0;
3212
3213         ref_root = btrfs_header_owner(buf);
3214         nritems = btrfs_header_nritems(buf);
3215         level = btrfs_header_level(buf);
3216
3217         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3218                 return 0;
3219
3220         if (inc)
3221                 process_func = btrfs_inc_extent_ref;
3222         else
3223                 process_func = btrfs_free_extent;
3224
3225         if (full_backref)
3226                 parent = buf->start;
3227         else
3228                 parent = 0;
3229
3230         for (i = 0; i < nritems; i++) {
3231                 if (level == 0) {
3232                         btrfs_item_key_to_cpu(buf, &key, i);
3233                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3234                                 continue;
3235                         fi = btrfs_item_ptr(buf, i,
3236                                             struct btrfs_file_extent_item);
3237                         if (btrfs_file_extent_type(buf, fi) ==
3238                             BTRFS_FILE_EXTENT_INLINE)
3239                                 continue;
3240                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3241                         if (bytenr == 0)
3242                                 continue;
3243
3244                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3245                         key.offset -= btrfs_file_extent_offset(buf, fi);
3246                         ret = process_func(trans, root, bytenr, num_bytes,
3247                                            parent, ref_root, key.objectid,
3248                                            key.offset);
3249                         if (ret)
3250                                 goto fail;
3251                 } else {
3252                         bytenr = btrfs_node_blockptr(buf, i);
3253                         num_bytes = root->nodesize;
3254                         ret = process_func(trans, root, bytenr, num_bytes,
3255                                            parent, ref_root, level - 1, 0);
3256                         if (ret)
3257                                 goto fail;
3258                 }
3259         }
3260         return 0;
3261 fail:
3262         return ret;
3263 }
3264
3265 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3266                   struct extent_buffer *buf, int full_backref)
3267 {
3268         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3269 }
3270
3271 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3272                   struct extent_buffer *buf, int full_backref)
3273 {
3274         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3275 }
3276
3277 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3278                                  struct btrfs_root *root,
3279                                  struct btrfs_path *path,
3280                                  struct btrfs_block_group_cache *cache)
3281 {
3282         int ret;
3283         struct btrfs_root *extent_root = root->fs_info->extent_root;
3284         unsigned long bi;
3285         struct extent_buffer *leaf;
3286
3287         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3288         if (ret) {
3289                 if (ret > 0)
3290                         ret = -ENOENT;
3291                 goto fail;
3292         }
3293
3294         leaf = path->nodes[0];
3295         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3296         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3297         btrfs_mark_buffer_dirty(leaf);
3298 fail:
3299         btrfs_release_path(path);
3300         return ret;
3301
3302 }
3303
3304 static struct btrfs_block_group_cache *
3305 next_block_group(struct btrfs_root *root,
3306                  struct btrfs_block_group_cache *cache)
3307 {
3308         struct rb_node *node;
3309
3310         spin_lock(&root->fs_info->block_group_cache_lock);
3311
3312         /* If our block group was removed, we need a full search. */
3313         if (RB_EMPTY_NODE(&cache->cache_node)) {
3314                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3315
3316                 spin_unlock(&root->fs_info->block_group_cache_lock);
3317                 btrfs_put_block_group(cache);
3318                 cache = btrfs_lookup_first_block_group(root->fs_info,
3319                                                        next_bytenr);
3320                 return cache;
3321         }
3322         node = rb_next(&cache->cache_node);
3323         btrfs_put_block_group(cache);
3324         if (node) {
3325                 cache = rb_entry(node, struct btrfs_block_group_cache,
3326                                  cache_node);
3327                 btrfs_get_block_group(cache);
3328         } else
3329                 cache = NULL;
3330         spin_unlock(&root->fs_info->block_group_cache_lock);
3331         return cache;
3332 }
3333
3334 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3335                             struct btrfs_trans_handle *trans,
3336                             struct btrfs_path *path)
3337 {
3338         struct btrfs_root *root = block_group->fs_info->tree_root;
3339         struct inode *inode = NULL;
3340         u64 alloc_hint = 0;
3341         int dcs = BTRFS_DC_ERROR;
3342         u64 num_pages = 0;
3343         int retries = 0;
3344         int ret = 0;
3345
3346         /*
3347          * If this block group is smaller than 100 megs don't bother caching the
3348          * block group.
3349          */
3350         if (block_group->key.offset < (100 * SZ_1M)) {
3351                 spin_lock(&block_group->lock);
3352                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3353                 spin_unlock(&block_group->lock);
3354                 return 0;
3355         }
3356
3357         if (trans->aborted)
3358                 return 0;
3359 again:
3360         inode = lookup_free_space_inode(root, block_group, path);
3361         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3362                 ret = PTR_ERR(inode);
3363                 btrfs_release_path(path);
3364                 goto out;
3365         }
3366
3367         if (IS_ERR(inode)) {
3368                 BUG_ON(retries);
3369                 retries++;
3370
3371                 if (block_group->ro)
3372                         goto out_free;
3373
3374                 ret = create_free_space_inode(root, trans, block_group, path);
3375                 if (ret)
3376                         goto out_free;
3377                 goto again;
3378         }
3379
3380         /* We've already setup this transaction, go ahead and exit */
3381         if (block_group->cache_generation == trans->transid &&
3382             i_size_read(inode)) {
3383                 dcs = BTRFS_DC_SETUP;
3384                 goto out_put;
3385         }
3386
3387         /*
3388          * We want to set the generation to 0, that way if anything goes wrong
3389          * from here on out we know not to trust this cache when we load up next
3390          * time.
3391          */
3392         BTRFS_I(inode)->generation = 0;
3393         ret = btrfs_update_inode(trans, root, inode);
3394         if (ret) {
3395                 /*
3396                  * So theoretically we could recover from this, simply set the
3397                  * super cache generation to 0 so we know to invalidate the
3398                  * cache, but then we'd have to keep track of the block groups
3399                  * that fail this way so we know we _have_ to reset this cache
3400                  * before the next commit or risk reading stale cache.  So to
3401                  * limit our exposure to horrible edge cases lets just abort the
3402                  * transaction, this only happens in really bad situations
3403                  * anyway.
3404                  */
3405                 btrfs_abort_transaction(trans, root, ret);
3406                 goto out_put;
3407         }
3408         WARN_ON(ret);
3409
3410         if (i_size_read(inode) > 0) {
3411                 ret = btrfs_check_trunc_cache_free_space(root,
3412                                         &root->fs_info->global_block_rsv);
3413                 if (ret)
3414                         goto out_put;
3415
3416                 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3417                 if (ret)
3418                         goto out_put;
3419         }
3420
3421         spin_lock(&block_group->lock);
3422         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3423             !btrfs_test_opt(root, SPACE_CACHE)) {
3424                 /*
3425                  * don't bother trying to write stuff out _if_
3426                  * a) we're not cached,
3427                  * b) we're with nospace_cache mount option.
3428                  */
3429                 dcs = BTRFS_DC_WRITTEN;
3430                 spin_unlock(&block_group->lock);
3431                 goto out_put;
3432         }
3433         spin_unlock(&block_group->lock);
3434
3435         /*
3436          * We hit an ENOSPC when setting up the cache in this transaction, just
3437          * skip doing the setup, we've already cleared the cache so we're safe.
3438          */
3439         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3440                 ret = -ENOSPC;
3441                 goto out_put;
3442         }
3443
3444         /*
3445          * Try to preallocate enough space based on how big the block group is.
3446          * Keep in mind this has to include any pinned space which could end up
3447          * taking up quite a bit since it's not folded into the other space
3448          * cache.
3449          */
3450         num_pages = div_u64(block_group->key.offset, SZ_256M);
3451         if (!num_pages)
3452                 num_pages = 1;
3453
3454         num_pages *= 16;
3455         num_pages *= PAGE_SIZE;
3456
3457         ret = btrfs_check_data_free_space(inode, 0, num_pages);
3458         if (ret)
3459                 goto out_put;
3460
3461         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3462                                               num_pages, num_pages,
3463                                               &alloc_hint);
3464         /*
3465          * Our cache requires contiguous chunks so that we don't modify a bunch
3466          * of metadata or split extents when writing the cache out, which means
3467          * we can enospc if we are heavily fragmented in addition to just normal
3468          * out of space conditions.  So if we hit this just skip setting up any
3469          * other block groups for this transaction, maybe we'll unpin enough
3470          * space the next time around.
3471          */
3472         if (!ret)
3473                 dcs = BTRFS_DC_SETUP;
3474         else if (ret == -ENOSPC)
3475                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3476         btrfs_free_reserved_data_space(inode, 0, num_pages);
3477
3478 out_put:
3479         iput(inode);
3480 out_free:
3481         btrfs_release_path(path);
3482 out:
3483         spin_lock(&block_group->lock);
3484         if (!ret && dcs == BTRFS_DC_SETUP)
3485                 block_group->cache_generation = trans->transid;
3486         block_group->disk_cache_state = dcs;
3487         spin_unlock(&block_group->lock);
3488
3489         return ret;
3490 }
3491
3492 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3493                             struct btrfs_root *root)
3494 {
3495         struct btrfs_block_group_cache *cache, *tmp;
3496         struct btrfs_transaction *cur_trans = trans->transaction;
3497         struct btrfs_path *path;
3498
3499         if (list_empty(&cur_trans->dirty_bgs) ||
3500             !btrfs_test_opt(root, SPACE_CACHE))
3501                 return 0;
3502
3503         path = btrfs_alloc_path();
3504         if (!path)
3505                 return -ENOMEM;
3506
3507         /* Could add new block groups, use _safe just in case */
3508         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3509                                  dirty_list) {
3510                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3511                         cache_save_setup(cache, trans, path);
3512         }
3513
3514         btrfs_free_path(path);
3515         return 0;
3516 }
3517
3518 /*
3519  * transaction commit does final block group cache writeback during a
3520  * critical section where nothing is allowed to change the FS.  This is
3521  * required in order for the cache to actually match the block group,
3522  * but can introduce a lot of latency into the commit.
3523  *
3524  * So, btrfs_start_dirty_block_groups is here to kick off block group
3525  * cache IO.  There's a chance we'll have to redo some of it if the
3526  * block group changes again during the commit, but it greatly reduces
3527  * the commit latency by getting rid of the easy block groups while
3528  * we're still allowing others to join the commit.
3529  */
3530 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3531                                    struct btrfs_root *root)
3532 {
3533         struct btrfs_block_group_cache *cache;
3534         struct btrfs_transaction *cur_trans = trans->transaction;
3535         int ret = 0;
3536         int should_put;
3537         struct btrfs_path *path = NULL;
3538         LIST_HEAD(dirty);
3539         struct list_head *io = &cur_trans->io_bgs;
3540         int num_started = 0;
3541         int loops = 0;
3542
3543         spin_lock(&cur_trans->dirty_bgs_lock);
3544         if (list_empty(&cur_trans->dirty_bgs)) {
3545                 spin_unlock(&cur_trans->dirty_bgs_lock);
3546                 return 0;
3547         }
3548         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3549         spin_unlock(&cur_trans->dirty_bgs_lock);
3550
3551 again:
3552         /*
3553          * make sure all the block groups on our dirty list actually
3554          * exist
3555          */
3556         btrfs_create_pending_block_groups(trans, root);
3557
3558         if (!path) {
3559                 path = btrfs_alloc_path();
3560                 if (!path)
3561                         return -ENOMEM;
3562         }
3563
3564         /*
3565          * cache_write_mutex is here only to save us from balance or automatic
3566          * removal of empty block groups deleting this block group while we are
3567          * writing out the cache
3568          */
3569         mutex_lock(&trans->transaction->cache_write_mutex);
3570         while (!list_empty(&dirty)) {
3571                 cache = list_first_entry(&dirty,
3572                                          struct btrfs_block_group_cache,
3573                                          dirty_list);
3574                 /*
3575                  * this can happen if something re-dirties a block
3576                  * group that is already under IO.  Just wait for it to
3577                  * finish and then do it all again
3578                  */
3579                 if (!list_empty(&cache->io_list)) {
3580                         list_del_init(&cache->io_list);
3581                         btrfs_wait_cache_io(root, trans, cache,
3582                                             &cache->io_ctl, path,
3583                                             cache->key.objectid);
3584                         btrfs_put_block_group(cache);
3585                 }
3586
3587
3588                 /*
3589                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3590                  * if it should update the cache_state.  Don't delete
3591                  * until after we wait.
3592                  *
3593                  * Since we're not running in the commit critical section
3594                  * we need the dirty_bgs_lock to protect from update_block_group
3595                  */
3596                 spin_lock(&cur_trans->dirty_bgs_lock);
3597                 list_del_init(&cache->dirty_list);
3598                 spin_unlock(&cur_trans->dirty_bgs_lock);
3599
3600                 should_put = 1;
3601
3602                 cache_save_setup(cache, trans, path);
3603
3604                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3605                         cache->io_ctl.inode = NULL;
3606                         ret = btrfs_write_out_cache(root, trans, cache, path);
3607                         if (ret == 0 && cache->io_ctl.inode) {
3608                                 num_started++;
3609                                 should_put = 0;
3610
3611                                 /*
3612                                  * the cache_write_mutex is protecting
3613                                  * the io_list
3614                                  */
3615                                 list_add_tail(&cache->io_list, io);
3616                         } else {
3617                                 /*
3618                                  * if we failed to write the cache, the
3619                                  * generation will be bad and life goes on
3620                                  */
3621                                 ret = 0;
3622                         }
3623                 }
3624                 if (!ret) {
3625                         ret = write_one_cache_group(trans, root, path, cache);
3626                         /*
3627                          * Our block group might still be attached to the list
3628                          * of new block groups in the transaction handle of some
3629                          * other task (struct btrfs_trans_handle->new_bgs). This
3630                          * means its block group item isn't yet in the extent
3631                          * tree. If this happens ignore the error, as we will
3632                          * try again later in the critical section of the
3633                          * transaction commit.
3634                          */
3635                         if (ret == -ENOENT) {
3636                                 ret = 0;
3637                                 spin_lock(&cur_trans->dirty_bgs_lock);
3638                                 if (list_empty(&cache->dirty_list)) {
3639                                         list_add_tail(&cache->dirty_list,
3640                                                       &cur_trans->dirty_bgs);
3641                                         btrfs_get_block_group(cache);
3642                                 }
3643                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3644                         } else if (ret) {
3645                                 btrfs_abort_transaction(trans, root, ret);
3646                         }
3647                 }
3648
3649                 /* if its not on the io list, we need to put the block group */
3650                 if (should_put)
3651                         btrfs_put_block_group(cache);
3652
3653                 if (ret)
3654                         break;
3655
3656                 /*
3657                  * Avoid blocking other tasks for too long. It might even save
3658                  * us from writing caches for block groups that are going to be
3659                  * removed.
3660                  */
3661                 mutex_unlock(&trans->transaction->cache_write_mutex);
3662                 mutex_lock(&trans->transaction->cache_write_mutex);
3663         }
3664         mutex_unlock(&trans->transaction->cache_write_mutex);
3665
3666         /*
3667          * go through delayed refs for all the stuff we've just kicked off
3668          * and then loop back (just once)
3669          */
3670         ret = btrfs_run_delayed_refs(trans, root, 0);
3671         if (!ret && loops == 0) {
3672                 loops++;
3673                 spin_lock(&cur_trans->dirty_bgs_lock);
3674                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3675                 /*
3676                  * dirty_bgs_lock protects us from concurrent block group
3677                  * deletes too (not just cache_write_mutex).
3678                  */
3679                 if (!list_empty(&dirty)) {
3680                         spin_unlock(&cur_trans->dirty_bgs_lock);
3681                         goto again;
3682                 }
3683                 spin_unlock(&cur_trans->dirty_bgs_lock);
3684         }
3685
3686         btrfs_free_path(path);
3687         return ret;
3688 }
3689
3690 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3691                                    struct btrfs_root *root)
3692 {
3693         struct btrfs_block_group_cache *cache;
3694         struct btrfs_transaction *cur_trans = trans->transaction;
3695         int ret = 0;
3696         int should_put;
3697         struct btrfs_path *path;
3698         struct list_head *io = &cur_trans->io_bgs;
3699         int num_started = 0;
3700
3701         path = btrfs_alloc_path();
3702         if (!path)
3703                 return -ENOMEM;
3704
3705         /*
3706          * Even though we are in the critical section of the transaction commit,
3707          * we can still have concurrent tasks adding elements to this
3708          * transaction's list of dirty block groups. These tasks correspond to
3709          * endio free space workers started when writeback finishes for a
3710          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3711          * allocate new block groups as a result of COWing nodes of the root
3712          * tree when updating the free space inode. The writeback for the space
3713          * caches is triggered by an earlier call to
3714          * btrfs_start_dirty_block_groups() and iterations of the following
3715          * loop.
3716          * Also we want to do the cache_save_setup first and then run the
3717          * delayed refs to make sure we have the best chance at doing this all
3718          * in one shot.
3719          */
3720         spin_lock(&cur_trans->dirty_bgs_lock);
3721         while (!list_empty(&cur_trans->dirty_bgs)) {
3722                 cache = list_first_entry(&cur_trans->dirty_bgs,
3723                                          struct btrfs_block_group_cache,
3724                                          dirty_list);
3725
3726                 /*
3727                  * this can happen if cache_save_setup re-dirties a block
3728                  * group that is already under IO.  Just wait for it to
3729                  * finish and then do it all again
3730                  */
3731                 if (!list_empty(&cache->io_list)) {
3732                         spin_unlock(&cur_trans->dirty_bgs_lock);
3733                         list_del_init(&cache->io_list);
3734                         btrfs_wait_cache_io(root, trans, cache,
3735                                             &cache->io_ctl, path,
3736                                             cache->key.objectid);
3737                         btrfs_put_block_group(cache);
3738                         spin_lock(&cur_trans->dirty_bgs_lock);
3739                 }
3740
3741                 /*
3742                  * don't remove from the dirty list until after we've waited
3743                  * on any pending IO
3744                  */
3745                 list_del_init(&cache->dirty_list);
3746                 spin_unlock(&cur_trans->dirty_bgs_lock);
3747                 should_put = 1;
3748
3749                 cache_save_setup(cache, trans, path);
3750
3751                 if (!ret)
3752                         ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3753
3754                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3755                         cache->io_ctl.inode = NULL;
3756                         ret = btrfs_write_out_cache(root, trans, cache, path);
3757                         if (ret == 0 && cache->io_ctl.inode) {
3758                                 num_started++;
3759                                 should_put = 0;
3760                                 list_add_tail(&cache->io_list, io);
3761                         } else {
3762                                 /*
3763                                  * if we failed to write the cache, the
3764                                  * generation will be bad and life goes on
3765                                  */
3766                                 ret = 0;
3767                         }
3768                 }
3769                 if (!ret) {
3770                         ret = write_one_cache_group(trans, root, path, cache);
3771                         /*
3772                          * One of the free space endio workers might have
3773                          * created a new block group while updating a free space
3774                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3775                          * and hasn't released its transaction handle yet, in
3776                          * which case the new block group is still attached to
3777                          * its transaction handle and its creation has not
3778                          * finished yet (no block group item in the extent tree
3779                          * yet, etc). If this is the case, wait for all free
3780                          * space endio workers to finish and retry. This is a
3781                          * a very rare case so no need for a more efficient and
3782                          * complex approach.
3783                          */
3784                         if (ret == -ENOENT) {
3785                                 wait_event(cur_trans->writer_wait,
3786                                    atomic_read(&cur_trans->num_writers) == 1);
3787                                 ret = write_one_cache_group(trans, root, path,
3788                                                             cache);
3789                         }
3790                         if (ret)
3791                                 btrfs_abort_transaction(trans, root, ret);
3792                 }
3793
3794                 /* if its not on the io list, we need to put the block group */
3795                 if (should_put)
3796                         btrfs_put_block_group(cache);
3797                 spin_lock(&cur_trans->dirty_bgs_lock);
3798         }
3799         spin_unlock(&cur_trans->dirty_bgs_lock);
3800
3801         while (!list_empty(io)) {
3802                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3803                                          io_list);
3804                 list_del_init(&cache->io_list);
3805                 btrfs_wait_cache_io(root, trans, cache,
3806                                     &cache->io_ctl, path, cache->key.objectid);
3807                 btrfs_put_block_group(cache);
3808         }
3809
3810         btrfs_free_path(path);
3811         return ret;
3812 }
3813
3814 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3815 {
3816         struct btrfs_block_group_cache *block_group;
3817         int readonly = 0;
3818
3819         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3820         if (!block_group || block_group->ro)
3821                 readonly = 1;
3822         if (block_group)
3823                 btrfs_put_block_group(block_group);
3824         return readonly;
3825 }
3826
3827 static const char *alloc_name(u64 flags)
3828 {
3829         switch (flags) {
3830         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3831                 return "mixed";
3832         case BTRFS_BLOCK_GROUP_METADATA:
3833                 return "metadata";
3834         case BTRFS_BLOCK_GROUP_DATA:
3835                 return "data";
3836         case BTRFS_BLOCK_GROUP_SYSTEM:
3837                 return "system";
3838         default:
3839                 WARN_ON(1);
3840                 return "invalid-combination";
3841         };
3842 }
3843
3844 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3845                              u64 total_bytes, u64 bytes_used,
3846                              struct btrfs_space_info **space_info)
3847 {
3848         struct btrfs_space_info *found;
3849         int i;
3850         int factor;
3851         int ret;
3852
3853         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3854                      BTRFS_BLOCK_GROUP_RAID10))
3855                 factor = 2;
3856         else
3857                 factor = 1;
3858
3859         found = __find_space_info(info, flags);
3860         if (found) {
3861                 spin_lock(&found->lock);
3862                 found->total_bytes += total_bytes;
3863                 found->disk_total += total_bytes * factor;
3864                 found->bytes_used += bytes_used;
3865                 found->disk_used += bytes_used * factor;
3866                 if (total_bytes > 0)
3867                         found->full = 0;
3868                 spin_unlock(&found->lock);
3869                 *space_info = found;
3870                 return 0;
3871         }
3872         found = kzalloc(sizeof(*found), GFP_NOFS);
3873         if (!found)
3874                 return -ENOMEM;
3875
3876         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3877         if (ret) {
3878                 kfree(found);
3879                 return ret;
3880         }
3881
3882         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3883                 INIT_LIST_HEAD(&found->block_groups[i]);
3884         init_rwsem(&found->groups_sem);
3885         spin_lock_init(&found->lock);
3886         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3887         found->total_bytes = total_bytes;
3888         found->disk_total = total_bytes * factor;
3889         found->bytes_used = bytes_used;
3890         found->disk_used = bytes_used * factor;
3891         found->bytes_pinned = 0;
3892         found->bytes_reserved = 0;
3893         found->bytes_readonly = 0;
3894         found->bytes_may_use = 0;
3895         found->full = 0;
3896         found->max_extent_size = 0;
3897         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3898         found->chunk_alloc = 0;
3899         found->flush = 0;
3900         init_waitqueue_head(&found->wait);
3901         INIT_LIST_HEAD(&found->ro_bgs);
3902
3903         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3904                                     info->space_info_kobj, "%s",
3905                                     alloc_name(found->flags));
3906         if (ret) {
3907                 kfree(found);
3908                 return ret;
3909         }
3910
3911         *space_info = found;
3912         list_add_rcu(&found->list, &info->space_info);
3913         if (flags & BTRFS_BLOCK_GROUP_DATA)
3914                 info->data_sinfo = found;
3915
3916         return ret;
3917 }
3918
3919 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3920 {
3921         u64 extra_flags = chunk_to_extended(flags) &
3922                                 BTRFS_EXTENDED_PROFILE_MASK;
3923
3924         write_seqlock(&fs_info->profiles_lock);
3925         if (flags & BTRFS_BLOCK_GROUP_DATA)
3926                 fs_info->avail_data_alloc_bits |= extra_flags;
3927         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3928                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3929         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3930                 fs_info->avail_system_alloc_bits |= extra_flags;
3931         write_sequnlock(&fs_info->profiles_lock);
3932 }
3933
3934 /*
3935  * returns target flags in extended format or 0 if restripe for this
3936  * chunk_type is not in progress
3937  *
3938  * should be called with either volume_mutex or balance_lock held
3939  */
3940 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3941 {
3942         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3943         u64 target = 0;
3944
3945         if (!bctl)
3946                 return 0;
3947
3948         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3949             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3950                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3951         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3952                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3953                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3954         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3955                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3956                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3957         }
3958
3959         return target;
3960 }
3961
3962 /*
3963  * @flags: available profiles in extended format (see ctree.h)
3964  *
3965  * Returns reduced profile in chunk format.  If profile changing is in
3966  * progress (either running or paused) picks the target profile (if it's
3967  * already available), otherwise falls back to plain reducing.
3968  */
3969 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3970 {
3971         u64 num_devices = root->fs_info->fs_devices->rw_devices;
3972         u64 target;
3973         u64 raid_type;
3974         u64 allowed = 0;
3975
3976         /*
3977          * see if restripe for this chunk_type is in progress, if so
3978          * try to reduce to the target profile
3979          */
3980         spin_lock(&root->fs_info->balance_lock);
3981         target = get_restripe_target(root->fs_info, flags);
3982         if (target) {
3983                 /* pick target profile only if it's already available */
3984                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3985                         spin_unlock(&root->fs_info->balance_lock);
3986                         return extended_to_chunk(target);
3987                 }
3988         }
3989         spin_unlock(&root->fs_info->balance_lock);
3990
3991         /* First, mask out the RAID levels which aren't possible */
3992         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
3993                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
3994                         allowed |= btrfs_raid_group[raid_type];
3995         }
3996         allowed &= flags;
3997
3998         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
3999                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4000         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4001                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4002         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4003                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4004         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4005                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4006         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4007                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4008
4009         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4010
4011         return extended_to_chunk(flags | allowed);
4012 }
4013
4014 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
4015 {
4016         unsigned seq;
4017         u64 flags;
4018
4019         do {
4020                 flags = orig_flags;
4021                 seq = read_seqbegin(&root->fs_info->profiles_lock);
4022
4023                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4024                         flags |= root->fs_info->avail_data_alloc_bits;
4025                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4026                         flags |= root->fs_info->avail_system_alloc_bits;
4027                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4028                         flags |= root->fs_info->avail_metadata_alloc_bits;
4029         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
4030
4031         return btrfs_reduce_alloc_profile(root, flags);
4032 }
4033
4034 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4035 {
4036         u64 flags;
4037         u64 ret;
4038
4039         if (data)
4040                 flags = BTRFS_BLOCK_GROUP_DATA;
4041         else if (root == root->fs_info->chunk_root)
4042                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4043         else
4044                 flags = BTRFS_BLOCK_GROUP_METADATA;
4045
4046         ret = get_alloc_profile(root, flags);
4047         return ret;
4048 }
4049
4050 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
4051 {
4052         struct btrfs_space_info *data_sinfo;
4053         struct btrfs_root *root = BTRFS_I(inode)->root;
4054         struct btrfs_fs_info *fs_info = root->fs_info;
4055         u64 used;
4056         int ret = 0;
4057         int need_commit = 2;
4058         int have_pinned_space;
4059
4060         /* make sure bytes are sectorsize aligned */
4061         bytes = ALIGN(bytes, root->sectorsize);
4062
4063         if (btrfs_is_free_space_inode(inode)) {
4064                 need_commit = 0;
4065                 ASSERT(current->journal_info);
4066         }
4067
4068         data_sinfo = fs_info->data_sinfo;
4069         if (!data_sinfo)
4070                 goto alloc;
4071
4072 again:
4073         /* make sure we have enough space to handle the data first */
4074         spin_lock(&data_sinfo->lock);
4075         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
4076                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
4077                 data_sinfo->bytes_may_use;
4078
4079         if (used + bytes > data_sinfo->total_bytes) {
4080                 struct btrfs_trans_handle *trans;
4081
4082                 /*
4083                  * if we don't have enough free bytes in this space then we need
4084                  * to alloc a new chunk.
4085                  */
4086                 if (!data_sinfo->full) {
4087                         u64 alloc_target;
4088
4089                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4090                         spin_unlock(&data_sinfo->lock);
4091 alloc:
4092                         alloc_target = btrfs_get_alloc_profile(root, 1);
4093                         /*
4094                          * It is ugly that we don't call nolock join
4095                          * transaction for the free space inode case here.
4096                          * But it is safe because we only do the data space
4097                          * reservation for the free space cache in the
4098                          * transaction context, the common join transaction
4099                          * just increase the counter of the current transaction
4100                          * handler, doesn't try to acquire the trans_lock of
4101                          * the fs.
4102                          */
4103                         trans = btrfs_join_transaction(root);
4104                         if (IS_ERR(trans))
4105                                 return PTR_ERR(trans);
4106
4107                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4108                                              alloc_target,
4109                                              CHUNK_ALLOC_NO_FORCE);
4110                         btrfs_end_transaction(trans, root);
4111                         if (ret < 0) {
4112                                 if (ret != -ENOSPC)
4113                                         return ret;
4114                                 else {
4115                                         have_pinned_space = 1;
4116                                         goto commit_trans;
4117                                 }
4118                         }
4119
4120                         if (!data_sinfo)
4121                                 data_sinfo = fs_info->data_sinfo;
4122
4123                         goto again;
4124                 }
4125
4126                 /*
4127                  * If we don't have enough pinned space to deal with this
4128                  * allocation, and no removed chunk in current transaction,
4129                  * don't bother committing the transaction.
4130                  */
4131                 have_pinned_space = percpu_counter_compare(
4132                         &data_sinfo->total_bytes_pinned,
4133                         used + bytes - data_sinfo->total_bytes);
4134                 spin_unlock(&data_sinfo->lock);
4135
4136                 /* commit the current transaction and try again */
4137 commit_trans:
4138                 if (need_commit &&
4139                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
4140                         need_commit--;
4141
4142                         if (need_commit > 0) {
4143                                 btrfs_start_delalloc_roots(fs_info, 0, -1);
4144                                 btrfs_wait_ordered_roots(fs_info, -1);
4145                         }
4146
4147                         trans = btrfs_join_transaction(root);
4148                         if (IS_ERR(trans))
4149                                 return PTR_ERR(trans);
4150                         if (have_pinned_space >= 0 ||
4151                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4152                                      &trans->transaction->flags) ||
4153                             need_commit > 0) {
4154                                 ret = btrfs_commit_transaction(trans, root);
4155                                 if (ret)
4156                                         return ret;
4157                                 /*
4158                                  * The cleaner kthread might still be doing iput
4159                                  * operations. Wait for it to finish so that
4160                                  * more space is released.
4161                                  */
4162                                 mutex_lock(&root->fs_info->cleaner_delayed_iput_mutex);
4163                                 mutex_unlock(&root->fs_info->cleaner_delayed_iput_mutex);
4164                                 goto again;
4165                         } else {
4166                                 btrfs_end_transaction(trans, root);
4167                         }
4168                 }
4169
4170                 trace_btrfs_space_reservation(root->fs_info,
4171                                               "space_info:enospc",
4172                                               data_sinfo->flags, bytes, 1);
4173                 return -ENOSPC;
4174         }
4175         data_sinfo->bytes_may_use += bytes;
4176         trace_btrfs_space_reservation(root->fs_info, "space_info",
4177                                       data_sinfo->flags, bytes, 1);
4178         spin_unlock(&data_sinfo->lock);
4179
4180         return ret;
4181 }
4182
4183 /*
4184  * New check_data_free_space() with ability for precious data reservation
4185  * Will replace old btrfs_check_data_free_space(), but for patch split,
4186  * add a new function first and then replace it.
4187  */
4188 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4189 {
4190         struct btrfs_root *root = BTRFS_I(inode)->root;
4191         int ret;
4192
4193         /* align the range */
4194         len = round_up(start + len, root->sectorsize) -
4195               round_down(start, root->sectorsize);
4196         start = round_down(start, root->sectorsize);
4197
4198         ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4199         if (ret < 0)
4200                 return ret;
4201
4202         /*
4203          * Use new btrfs_qgroup_reserve_data to reserve precious data space
4204          *
4205          * TODO: Find a good method to avoid reserve data space for NOCOW
4206          * range, but don't impact performance on quota disable case.
4207          */
4208         ret = btrfs_qgroup_reserve_data(inode, start, len);
4209         return ret;
4210 }
4211
4212 /*
4213  * Called if we need to clear a data reservation for this inode
4214  * Normally in a error case.
4215  *
4216  * This one will *NOT* use accurate qgroup reserved space API, just for case
4217  * which we can't sleep and is sure it won't affect qgroup reserved space.
4218  * Like clear_bit_hook().
4219  */
4220 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4221                                             u64 len)
4222 {
4223         struct btrfs_root *root = BTRFS_I(inode)->root;
4224         struct btrfs_space_info *data_sinfo;
4225
4226         /* Make sure the range is aligned to sectorsize */
4227         len = round_up(start + len, root->sectorsize) -
4228               round_down(start, root->sectorsize);
4229         start = round_down(start, root->sectorsize);
4230
4231         data_sinfo = root->fs_info->data_sinfo;
4232         spin_lock(&data_sinfo->lock);
4233         if (WARN_ON(data_sinfo->bytes_may_use < len))
4234                 data_sinfo->bytes_may_use = 0;
4235         else
4236                 data_sinfo->bytes_may_use -= len;
4237         trace_btrfs_space_reservation(root->fs_info, "space_info",
4238                                       data_sinfo->flags, len, 0);
4239         spin_unlock(&data_sinfo->lock);
4240 }
4241
4242 /*
4243  * Called if we need to clear a data reservation for this inode
4244  * Normally in a error case.
4245  *
4246  * This one will handle the per-indoe data rsv map for accurate reserved
4247  * space framework.
4248  */
4249 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4250 {
4251         btrfs_free_reserved_data_space_noquota(inode, start, len);
4252         btrfs_qgroup_free_data(inode, start, len);
4253 }
4254
4255 static void force_metadata_allocation(struct btrfs_fs_info *info)
4256 {
4257         struct list_head *head = &info->space_info;
4258         struct btrfs_space_info *found;
4259
4260         rcu_read_lock();
4261         list_for_each_entry_rcu(found, head, list) {
4262                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4263                         found->force_alloc = CHUNK_ALLOC_FORCE;
4264         }
4265         rcu_read_unlock();
4266 }
4267
4268 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4269 {
4270         return (global->size << 1);
4271 }
4272
4273 static int should_alloc_chunk(struct btrfs_root *root,
4274                               struct btrfs_space_info *sinfo, int force)
4275 {
4276         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4277         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4278         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4279         u64 thresh;
4280
4281         if (force == CHUNK_ALLOC_FORCE)
4282                 return 1;
4283
4284         /*
4285          * We need to take into account the global rsv because for all intents
4286          * and purposes it's used space.  Don't worry about locking the
4287          * global_rsv, it doesn't change except when the transaction commits.
4288          */
4289         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4290                 num_allocated += calc_global_rsv_need_space(global_rsv);
4291
4292         /*
4293          * in limited mode, we want to have some free space up to
4294          * about 1% of the FS size.
4295          */
4296         if (force == CHUNK_ALLOC_LIMITED) {
4297                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4298                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4299
4300                 if (num_bytes - num_allocated < thresh)
4301                         return 1;
4302         }
4303
4304         if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4305                 return 0;
4306         return 1;
4307 }
4308
4309 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4310 {
4311         u64 num_dev;
4312
4313         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4314                     BTRFS_BLOCK_GROUP_RAID0 |
4315                     BTRFS_BLOCK_GROUP_RAID5 |
4316                     BTRFS_BLOCK_GROUP_RAID6))
4317                 num_dev = root->fs_info->fs_devices->rw_devices;
4318         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4319                 num_dev = 2;
4320         else
4321                 num_dev = 1;    /* DUP or single */
4322
4323         return num_dev;
4324 }
4325
4326 /*
4327  * If @is_allocation is true, reserve space in the system space info necessary
4328  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4329  * removing a chunk.
4330  */
4331 void check_system_chunk(struct btrfs_trans_handle *trans,
4332                         struct btrfs_root *root,
4333                         u64 type)
4334 {
4335         struct btrfs_space_info *info;
4336         u64 left;
4337         u64 thresh;
4338         int ret = 0;
4339         u64 num_devs;
4340
4341         /*
4342          * Needed because we can end up allocating a system chunk and for an
4343          * atomic and race free space reservation in the chunk block reserve.
4344          */
4345         ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4346
4347         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4348         spin_lock(&info->lock);
4349         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4350                 info->bytes_reserved - info->bytes_readonly -
4351                 info->bytes_may_use;
4352         spin_unlock(&info->lock);
4353
4354         num_devs = get_profile_num_devs(root, type);
4355
4356         /* num_devs device items to update and 1 chunk item to add or remove */
4357         thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4358                 btrfs_calc_trans_metadata_size(root, 1);
4359
4360         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
4361                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4362                         left, thresh, type);
4363                 dump_space_info(info, 0, 0);
4364         }
4365
4366         if (left < thresh) {
4367                 u64 flags;
4368
4369                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4370                 /*
4371                  * Ignore failure to create system chunk. We might end up not
4372                  * needing it, as we might not need to COW all nodes/leafs from
4373                  * the paths we visit in the chunk tree (they were already COWed
4374                  * or created in the current transaction for example).
4375                  */
4376                 ret = btrfs_alloc_chunk(trans, root, flags);
4377         }
4378
4379         if (!ret) {
4380                 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4381                                           &root->fs_info->chunk_block_rsv,
4382                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4383                 if (!ret)
4384                         trans->chunk_bytes_reserved += thresh;
4385         }
4386 }
4387
4388 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4389                           struct btrfs_root *extent_root, u64 flags, int force)
4390 {
4391         struct btrfs_space_info *space_info;
4392         struct btrfs_fs_info *fs_info = extent_root->fs_info;
4393         int wait_for_alloc = 0;
4394         int ret = 0;
4395
4396         /* Don't re-enter if we're already allocating a chunk */
4397         if (trans->allocating_chunk)
4398                 return -ENOSPC;
4399
4400         space_info = __find_space_info(extent_root->fs_info, flags);
4401         if (!space_info) {
4402                 ret = update_space_info(extent_root->fs_info, flags,
4403                                         0, 0, &space_info);
4404                 BUG_ON(ret); /* -ENOMEM */
4405         }
4406         BUG_ON(!space_info); /* Logic error */
4407
4408 again:
4409         spin_lock(&space_info->lock);
4410         if (force < space_info->force_alloc)
4411                 force = space_info->force_alloc;
4412         if (space_info->full) {
4413                 if (should_alloc_chunk(extent_root, space_info, force))
4414                         ret = -ENOSPC;
4415                 else
4416                         ret = 0;
4417                 spin_unlock(&space_info->lock);
4418                 return ret;
4419         }
4420
4421         if (!should_alloc_chunk(extent_root, space_info, force)) {
4422                 spin_unlock(&space_info->lock);
4423                 return 0;
4424         } else if (space_info->chunk_alloc) {
4425                 wait_for_alloc = 1;
4426         } else {
4427                 space_info->chunk_alloc = 1;
4428         }
4429
4430         spin_unlock(&space_info->lock);
4431
4432         mutex_lock(&fs_info->chunk_mutex);
4433
4434         /*
4435          * The chunk_mutex is held throughout the entirety of a chunk
4436          * allocation, so once we've acquired the chunk_mutex we know that the
4437          * other guy is done and we need to recheck and see if we should
4438          * allocate.
4439          */
4440         if (wait_for_alloc) {
4441                 mutex_unlock(&fs_info->chunk_mutex);
4442                 wait_for_alloc = 0;
4443                 goto again;
4444         }
4445
4446         trans->allocating_chunk = true;
4447
4448         /*
4449          * If we have mixed data/metadata chunks we want to make sure we keep
4450          * allocating mixed chunks instead of individual chunks.
4451          */
4452         if (btrfs_mixed_space_info(space_info))
4453                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4454
4455         /*
4456          * if we're doing a data chunk, go ahead and make sure that
4457          * we keep a reasonable number of metadata chunks allocated in the
4458          * FS as well.
4459          */
4460         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4461                 fs_info->data_chunk_allocations++;
4462                 if (!(fs_info->data_chunk_allocations %
4463                       fs_info->metadata_ratio))
4464                         force_metadata_allocation(fs_info);
4465         }
4466
4467         /*
4468          * Check if we have enough space in SYSTEM chunk because we may need
4469          * to update devices.
4470          */
4471         check_system_chunk(trans, extent_root, flags);
4472
4473         ret = btrfs_alloc_chunk(trans, extent_root, flags);
4474         trans->allocating_chunk = false;
4475
4476         spin_lock(&space_info->lock);
4477         if (ret < 0 && ret != -ENOSPC)
4478                 goto out;
4479         if (ret)
4480                 space_info->full = 1;
4481         else
4482                 ret = 1;
4483
4484         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4485 out:
4486         space_info->chunk_alloc = 0;
4487         spin_unlock(&space_info->lock);
4488         mutex_unlock(&fs_info->chunk_mutex);
4489         /*
4490          * When we allocate a new chunk we reserve space in the chunk block
4491          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4492          * add new nodes/leafs to it if we end up needing to do it when
4493          * inserting the chunk item and updating device items as part of the
4494          * second phase of chunk allocation, performed by
4495          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4496          * large number of new block groups to create in our transaction
4497          * handle's new_bgs list to avoid exhausting the chunk block reserve
4498          * in extreme cases - like having a single transaction create many new
4499          * block groups when starting to write out the free space caches of all
4500          * the block groups that were made dirty during the lifetime of the
4501          * transaction.
4502          */
4503         if (trans->can_flush_pending_bgs &&
4504             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4505                 btrfs_create_pending_block_groups(trans, trans->root);
4506                 btrfs_trans_release_chunk_metadata(trans);
4507         }
4508         return ret;
4509 }
4510
4511 static int can_overcommit(struct btrfs_root *root,
4512                           struct btrfs_space_info *space_info, u64 bytes,
4513                           enum btrfs_reserve_flush_enum flush)
4514 {
4515         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4516         u64 profile = btrfs_get_alloc_profile(root, 0);
4517         u64 space_size;
4518         u64 avail;
4519         u64 used;
4520
4521         used = space_info->bytes_used + space_info->bytes_reserved +
4522                 space_info->bytes_pinned + space_info->bytes_readonly;
4523
4524         /*
4525          * We only want to allow over committing if we have lots of actual space
4526          * free, but if we don't have enough space to handle the global reserve
4527          * space then we could end up having a real enospc problem when trying
4528          * to allocate a chunk or some other such important allocation.
4529          */
4530         spin_lock(&global_rsv->lock);
4531         space_size = calc_global_rsv_need_space(global_rsv);
4532         spin_unlock(&global_rsv->lock);
4533         if (used + space_size >= space_info->total_bytes)
4534                 return 0;
4535
4536         used += space_info->bytes_may_use;
4537
4538         spin_lock(&root->fs_info->free_chunk_lock);
4539         avail = root->fs_info->free_chunk_space;
4540         spin_unlock(&root->fs_info->free_chunk_lock);
4541
4542         /*
4543          * If we have dup, raid1 or raid10 then only half of the free
4544          * space is actually useable.  For raid56, the space info used
4545          * doesn't include the parity drive, so we don't have to
4546          * change the math
4547          */
4548         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4549                        BTRFS_BLOCK_GROUP_RAID1 |
4550                        BTRFS_BLOCK_GROUP_RAID10))
4551                 avail >>= 1;
4552
4553         /*
4554          * If we aren't flushing all things, let us overcommit up to
4555          * 1/2th of the space. If we can flush, don't let us overcommit
4556          * too much, let it overcommit up to 1/8 of the space.
4557          */
4558         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4559                 avail >>= 3;
4560         else
4561                 avail >>= 1;
4562
4563         if (used + bytes < space_info->total_bytes + avail)
4564                 return 1;
4565         return 0;
4566 }
4567
4568 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4569                                          unsigned long nr_pages, int nr_items)
4570 {
4571         struct super_block *sb = root->fs_info->sb;
4572
4573         if (down_read_trylock(&sb->s_umount)) {
4574                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4575                 up_read(&sb->s_umount);
4576         } else {
4577                 /*
4578                  * We needn't worry the filesystem going from r/w to r/o though
4579                  * we don't acquire ->s_umount mutex, because the filesystem
4580                  * should guarantee the delalloc inodes list be empty after
4581                  * the filesystem is readonly(all dirty pages are written to
4582                  * the disk).
4583                  */
4584                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4585                 if (!current->journal_info)
4586                         btrfs_wait_ordered_roots(root->fs_info, nr_items);
4587         }
4588 }
4589
4590 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4591 {
4592         u64 bytes;
4593         int nr;
4594
4595         bytes = btrfs_calc_trans_metadata_size(root, 1);
4596         nr = (int)div64_u64(to_reclaim, bytes);
4597         if (!nr)
4598                 nr = 1;
4599         return nr;
4600 }
4601
4602 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4603
4604 /*
4605  * shrink metadata reservation for delalloc
4606  */
4607 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4608                             bool wait_ordered)
4609 {
4610         struct btrfs_block_rsv *block_rsv;
4611         struct btrfs_space_info *space_info;
4612         struct btrfs_trans_handle *trans;
4613         u64 delalloc_bytes;
4614         u64 max_reclaim;
4615         long time_left;
4616         unsigned long nr_pages;
4617         int loops;
4618         int items;
4619         enum btrfs_reserve_flush_enum flush;
4620
4621         /* Calc the number of the pages we need flush for space reservation */
4622         items = calc_reclaim_items_nr(root, to_reclaim);
4623         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4624
4625         trans = (struct btrfs_trans_handle *)current->journal_info;
4626         block_rsv = &root->fs_info->delalloc_block_rsv;
4627         space_info = block_rsv->space_info;
4628
4629         delalloc_bytes = percpu_counter_sum_positive(
4630                                                 &root->fs_info->delalloc_bytes);
4631         if (delalloc_bytes == 0) {
4632                 if (trans)
4633                         return;
4634                 if (wait_ordered)
4635                         btrfs_wait_ordered_roots(root->fs_info, items);
4636                 return;
4637         }
4638
4639         loops = 0;
4640         while (delalloc_bytes && loops < 3) {
4641                 max_reclaim = min(delalloc_bytes, to_reclaim);
4642                 nr_pages = max_reclaim >> PAGE_SHIFT;
4643                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4644                 /*
4645                  * We need to wait for the async pages to actually start before
4646                  * we do anything.
4647                  */
4648                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4649                 if (!max_reclaim)
4650                         goto skip_async;
4651
4652                 if (max_reclaim <= nr_pages)
4653                         max_reclaim = 0;
4654                 else
4655                         max_reclaim -= nr_pages;
4656
4657                 wait_event(root->fs_info->async_submit_wait,
4658                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4659                            (int)max_reclaim);
4660 skip_async:
4661                 if (!trans)
4662                         flush = BTRFS_RESERVE_FLUSH_ALL;
4663                 else
4664                         flush = BTRFS_RESERVE_NO_FLUSH;
4665                 spin_lock(&space_info->lock);
4666                 if (can_overcommit(root, space_info, orig, flush)) {
4667                         spin_unlock(&space_info->lock);
4668                         break;
4669                 }
4670                 spin_unlock(&space_info->lock);
4671
4672                 loops++;
4673                 if (wait_ordered && !trans) {
4674                         btrfs_wait_ordered_roots(root->fs_info, items);
4675                 } else {
4676                         time_left = schedule_timeout_killable(1);
4677                         if (time_left)
4678                                 break;
4679                 }
4680                 delalloc_bytes = percpu_counter_sum_positive(
4681                                                 &root->fs_info->delalloc_bytes);
4682         }
4683 }
4684
4685 /**
4686  * maybe_commit_transaction - possibly commit the transaction if its ok to
4687  * @root - the root we're allocating for
4688  * @bytes - the number of bytes we want to reserve
4689  * @force - force the commit
4690  *
4691  * This will check to make sure that committing the transaction will actually
4692  * get us somewhere and then commit the transaction if it does.  Otherwise it
4693  * will return -ENOSPC.
4694  */
4695 static int may_commit_transaction(struct btrfs_root *root,
4696                                   struct btrfs_space_info *space_info,
4697                                   u64 bytes, int force)
4698 {
4699         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4700         struct btrfs_trans_handle *trans;
4701
4702         trans = (struct btrfs_trans_handle *)current->journal_info;
4703         if (trans)
4704                 return -EAGAIN;
4705
4706         if (force)
4707                 goto commit;
4708
4709         /* See if there is enough pinned space to make this reservation */
4710         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4711                                    bytes) >= 0)
4712                 goto commit;
4713
4714         /*
4715          * See if there is some space in the delayed insertion reservation for
4716          * this reservation.
4717          */
4718         if (space_info != delayed_rsv->space_info)
4719                 return -ENOSPC;
4720
4721         spin_lock(&delayed_rsv->lock);
4722         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4723                                    bytes - delayed_rsv->size) >= 0) {
4724                 spin_unlock(&delayed_rsv->lock);
4725                 return -ENOSPC;
4726         }
4727         spin_unlock(&delayed_rsv->lock);
4728
4729 commit:
4730         trans = btrfs_join_transaction(root);
4731         if (IS_ERR(trans))
4732                 return -ENOSPC;
4733
4734         return btrfs_commit_transaction(trans, root);
4735 }
4736
4737 enum flush_state {
4738         FLUSH_DELAYED_ITEMS_NR  =       1,
4739         FLUSH_DELAYED_ITEMS     =       2,
4740         FLUSH_DELALLOC          =       3,
4741         FLUSH_DELALLOC_WAIT     =       4,
4742         ALLOC_CHUNK             =       5,
4743         COMMIT_TRANS            =       6,
4744 };
4745
4746 static int flush_space(struct btrfs_root *root,
4747                        struct btrfs_space_info *space_info, u64 num_bytes,
4748                        u64 orig_bytes, int state)
4749 {
4750         struct btrfs_trans_handle *trans;
4751         int nr;
4752         int ret = 0;
4753
4754         switch (state) {
4755         case FLUSH_DELAYED_ITEMS_NR:
4756         case FLUSH_DELAYED_ITEMS:
4757                 if (state == FLUSH_DELAYED_ITEMS_NR)
4758                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4759                 else
4760                         nr = -1;
4761
4762                 trans = btrfs_join_transaction(root);
4763                 if (IS_ERR(trans)) {
4764                         ret = PTR_ERR(trans);
4765                         break;
4766                 }
4767                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4768                 btrfs_end_transaction(trans, root);
4769                 break;
4770         case FLUSH_DELALLOC:
4771         case FLUSH_DELALLOC_WAIT:
4772                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4773                                 state == FLUSH_DELALLOC_WAIT);
4774                 break;
4775         case ALLOC_CHUNK:
4776                 trans = btrfs_join_transaction(root);
4777                 if (IS_ERR(trans)) {
4778                         ret = PTR_ERR(trans);
4779                         break;
4780                 }
4781                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4782                                      btrfs_get_alloc_profile(root, 0),
4783                                      CHUNK_ALLOC_NO_FORCE);
4784                 btrfs_end_transaction(trans, root);
4785                 if (ret == -ENOSPC)
4786                         ret = 0;
4787                 break;
4788         case COMMIT_TRANS:
4789                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4790                 break;
4791         default:
4792                 ret = -ENOSPC;
4793                 break;
4794         }
4795
4796         return ret;
4797 }
4798
4799 static inline u64
4800 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4801                                  struct btrfs_space_info *space_info)
4802 {
4803         u64 used;
4804         u64 expected;
4805         u64 to_reclaim;
4806
4807         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4808         spin_lock(&space_info->lock);
4809         if (can_overcommit(root, space_info, to_reclaim,
4810                            BTRFS_RESERVE_FLUSH_ALL)) {
4811                 to_reclaim = 0;
4812                 goto out;
4813         }
4814
4815         used = space_info->bytes_used + space_info->bytes_reserved +
4816                space_info->bytes_pinned + space_info->bytes_readonly +
4817                space_info->bytes_may_use;
4818         if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4819                 expected = div_factor_fine(space_info->total_bytes, 95);
4820         else
4821                 expected = div_factor_fine(space_info->total_bytes, 90);
4822
4823         if (used > expected)
4824                 to_reclaim = used - expected;
4825         else
4826                 to_reclaim = 0;
4827         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4828                                      space_info->bytes_reserved);
4829 out:
4830         spin_unlock(&space_info->lock);
4831
4832         return to_reclaim;
4833 }
4834
4835 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4836                                         struct btrfs_fs_info *fs_info, u64 used)
4837 {
4838         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4839
4840         /* If we're just plain full then async reclaim just slows us down. */
4841         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4842                 return 0;
4843
4844         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4845                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4846 }
4847
4848 static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info,
4849                                        struct btrfs_fs_info *fs_info,
4850                                        int flush_state)
4851 {
4852         u64 used;
4853
4854         spin_lock(&space_info->lock);
4855         /*
4856          * We run out of space and have not got any free space via flush_space,
4857          * so don't bother doing async reclaim.
4858          */
4859         if (flush_state > COMMIT_TRANS && space_info->full) {
4860                 spin_unlock(&space_info->lock);
4861                 return 0;
4862         }
4863
4864         used = space_info->bytes_used + space_info->bytes_reserved +
4865                space_info->bytes_pinned + space_info->bytes_readonly +
4866                space_info->bytes_may_use;
4867         if (need_do_async_reclaim(space_info, fs_info, used)) {
4868                 spin_unlock(&space_info->lock);
4869                 return 1;
4870         }
4871         spin_unlock(&space_info->lock);
4872
4873         return 0;
4874 }
4875
4876 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4877 {
4878         struct btrfs_fs_info *fs_info;
4879         struct btrfs_space_info *space_info;
4880         u64 to_reclaim;
4881         int flush_state;
4882
4883         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4884         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4885
4886         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4887                                                       space_info);
4888         if (!to_reclaim)
4889                 return;
4890
4891         flush_state = FLUSH_DELAYED_ITEMS_NR;
4892         do {
4893                 flush_space(fs_info->fs_root, space_info, to_reclaim,
4894                             to_reclaim, flush_state);
4895                 flush_state++;
4896                 if (!btrfs_need_do_async_reclaim(space_info, fs_info,
4897                                                  flush_state))
4898                         return;
4899         } while (flush_state < COMMIT_TRANS);
4900 }
4901
4902 void btrfs_init_async_reclaim_work(struct work_struct *work)
4903 {
4904         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
4905 }
4906
4907 /**
4908  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4909  * @root - the root we're allocating for
4910  * @block_rsv - the block_rsv we're allocating for
4911  * @orig_bytes - the number of bytes we want
4912  * @flush - whether or not we can flush to make our reservation
4913  *
4914  * This will reserve orgi_bytes number of bytes from the space info associated
4915  * with the block_rsv.  If there is not enough space it will make an attempt to
4916  * flush out space to make room.  It will do this by flushing delalloc if
4917  * possible or committing the transaction.  If flush is 0 then no attempts to
4918  * regain reservations will be made and this will fail if there is not enough
4919  * space already.
4920  */
4921 static int reserve_metadata_bytes(struct btrfs_root *root,
4922                                   struct btrfs_block_rsv *block_rsv,
4923                                   u64 orig_bytes,
4924                                   enum btrfs_reserve_flush_enum flush)
4925 {
4926         struct btrfs_space_info *space_info = block_rsv->space_info;
4927         u64 used;
4928         u64 num_bytes = orig_bytes;
4929         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4930         int ret = 0;
4931         bool flushing = false;
4932
4933 again:
4934         ret = 0;
4935         spin_lock(&space_info->lock);
4936         /*
4937          * We only want to wait if somebody other than us is flushing and we
4938          * are actually allowed to flush all things.
4939          */
4940         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4941                space_info->flush) {
4942                 spin_unlock(&space_info->lock);
4943                 /*
4944                  * If we have a trans handle we can't wait because the flusher
4945                  * may have to commit the transaction, which would mean we would
4946                  * deadlock since we are waiting for the flusher to finish, but
4947                  * hold the current transaction open.
4948                  */
4949                 if (current->journal_info)
4950                         return -EAGAIN;
4951                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4952                 /* Must have been killed, return */
4953                 if (ret)
4954                         return -EINTR;
4955
4956                 spin_lock(&space_info->lock);
4957         }
4958
4959         ret = -ENOSPC;
4960         used = space_info->bytes_used + space_info->bytes_reserved +
4961                 space_info->bytes_pinned + space_info->bytes_readonly +
4962                 space_info->bytes_may_use;
4963
4964         /*
4965          * The idea here is that we've not already over-reserved the block group
4966          * then we can go ahead and save our reservation first and then start
4967          * flushing if we need to.  Otherwise if we've already overcommitted
4968          * lets start flushing stuff first and then come back and try to make
4969          * our reservation.
4970          */
4971         if (used <= space_info->total_bytes) {
4972                 if (used + orig_bytes <= space_info->total_bytes) {
4973                         space_info->bytes_may_use += orig_bytes;
4974                         trace_btrfs_space_reservation(root->fs_info,
4975                                 "space_info", space_info->flags, orig_bytes, 1);
4976                         ret = 0;
4977                 } else {
4978                         /*
4979                          * Ok set num_bytes to orig_bytes since we aren't
4980                          * overocmmitted, this way we only try and reclaim what
4981                          * we need.
4982                          */
4983                         num_bytes = orig_bytes;
4984                 }
4985         } else {
4986                 /*
4987                  * Ok we're over committed, set num_bytes to the overcommitted
4988                  * amount plus the amount of bytes that we need for this
4989                  * reservation.
4990                  */
4991                 num_bytes = used - space_info->total_bytes +
4992                         (orig_bytes * 2);
4993         }
4994
4995         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4996                 space_info->bytes_may_use += orig_bytes;
4997                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4998                                               space_info->flags, orig_bytes,
4999                                               1);
5000                 ret = 0;
5001         }
5002
5003         /*
5004          * Couldn't make our reservation, save our place so while we're trying
5005          * to reclaim space we can actually use it instead of somebody else
5006          * stealing it from us.
5007          *
5008          * We make the other tasks wait for the flush only when we can flush
5009          * all things.
5010          */
5011         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5012                 flushing = true;
5013                 space_info->flush = 1;
5014         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5015                 used += orig_bytes;
5016                 /*
5017                  * We will do the space reservation dance during log replay,
5018                  * which means we won't have fs_info->fs_root set, so don't do
5019                  * the async reclaim as we will panic.
5020                  */
5021                 if (!root->fs_info->log_root_recovering &&
5022                     need_do_async_reclaim(space_info, root->fs_info, used) &&
5023                     !work_busy(&root->fs_info->async_reclaim_work))
5024                         queue_work(system_unbound_wq,
5025                                    &root->fs_info->async_reclaim_work);
5026         }
5027         spin_unlock(&space_info->lock);
5028
5029         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5030                 goto out;
5031
5032         ret = flush_space(root, space_info, num_bytes, orig_bytes,
5033                           flush_state);
5034         flush_state++;
5035
5036         /*
5037          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
5038          * would happen. So skip delalloc flush.
5039          */
5040         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
5041             (flush_state == FLUSH_DELALLOC ||
5042              flush_state == FLUSH_DELALLOC_WAIT))
5043                 flush_state = ALLOC_CHUNK;
5044
5045         if (!ret)
5046                 goto again;
5047         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
5048                  flush_state < COMMIT_TRANS)
5049                 goto again;
5050         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
5051                  flush_state <= COMMIT_TRANS)
5052                 goto again;
5053
5054 out:
5055         if (ret == -ENOSPC &&
5056             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5057                 struct btrfs_block_rsv *global_rsv =
5058                         &root->fs_info->global_block_rsv;
5059
5060                 if (block_rsv != global_rsv &&
5061                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5062                         ret = 0;
5063         }
5064         if (ret == -ENOSPC)
5065                 trace_btrfs_space_reservation(root->fs_info,
5066                                               "space_info:enospc",
5067                                               space_info->flags, orig_bytes, 1);
5068         if (flushing) {
5069                 spin_lock(&space_info->lock);
5070                 space_info->flush = 0;
5071                 wake_up_all(&space_info->wait);
5072                 spin_unlock(&space_info->lock);
5073         }
5074         return ret;
5075 }
5076
5077 static struct btrfs_block_rsv *get_block_rsv(
5078                                         const struct btrfs_trans_handle *trans,
5079                                         const struct btrfs_root *root)
5080 {
5081         struct btrfs_block_rsv *block_rsv = NULL;
5082
5083         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5084             (root == root->fs_info->csum_root && trans->adding_csums) ||
5085              (root == root->fs_info->uuid_root))
5086                 block_rsv = trans->block_rsv;
5087
5088         if (!block_rsv)
5089                 block_rsv = root->block_rsv;
5090
5091         if (!block_rsv)
5092                 block_rsv = &root->fs_info->empty_block_rsv;
5093
5094         return block_rsv;
5095 }
5096
5097 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5098                                u64 num_bytes)
5099 {
5100         int ret = -ENOSPC;
5101         spin_lock(&block_rsv->lock);
5102         if (block_rsv->reserved >= num_bytes) {
5103                 block_rsv->reserved -= num_bytes;
5104                 if (block_rsv->reserved < block_rsv->size)
5105                         block_rsv->full = 0;
5106                 ret = 0;
5107         }
5108         spin_unlock(&block_rsv->lock);
5109         return ret;
5110 }
5111
5112 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5113                                 u64 num_bytes, int update_size)
5114 {
5115         spin_lock(&block_rsv->lock);
5116         block_rsv->reserved += num_bytes;
5117         if (update_size)
5118                 block_rsv->size += num_bytes;
5119         else if (block_rsv->reserved >= block_rsv->size)
5120                 block_rsv->full = 1;
5121         spin_unlock(&block_rsv->lock);
5122 }
5123
5124 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5125                              struct btrfs_block_rsv *dest, u64 num_bytes,
5126                              int min_factor)
5127 {
5128         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5129         u64 min_bytes;
5130
5131         if (global_rsv->space_info != dest->space_info)
5132                 return -ENOSPC;
5133
5134         spin_lock(&global_rsv->lock);
5135         min_bytes = div_factor(global_rsv->size, min_factor);
5136         if (global_rsv->reserved < min_bytes + num_bytes) {
5137                 spin_unlock(&global_rsv->lock);
5138                 return -ENOSPC;
5139         }
5140         global_rsv->reserved -= num_bytes;
5141         if (global_rsv->reserved < global_rsv->size)
5142                 global_rsv->full = 0;
5143         spin_unlock(&global_rsv->lock);
5144
5145         block_rsv_add_bytes(dest, num_bytes, 1);
5146         return 0;
5147 }
5148
5149 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5150                                     struct btrfs_block_rsv *block_rsv,
5151                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5152 {
5153         struct btrfs_space_info *space_info = block_rsv->space_info;
5154
5155         spin_lock(&block_rsv->lock);
5156         if (num_bytes == (u64)-1)
5157                 num_bytes = block_rsv->size;
5158         block_rsv->size -= num_bytes;
5159         if (block_rsv->reserved >= block_rsv->size) {
5160                 num_bytes = block_rsv->reserved - block_rsv->size;
5161                 block_rsv->reserved = block_rsv->size;
5162                 block_rsv->full = 1;
5163         } else {
5164                 num_bytes = 0;
5165         }
5166         spin_unlock(&block_rsv->lock);
5167
5168         if (num_bytes > 0) {
5169                 if (dest) {
5170                         spin_lock(&dest->lock);
5171                         if (!dest->full) {
5172                                 u64 bytes_to_add;
5173
5174                                 bytes_to_add = dest->size - dest->reserved;
5175                                 bytes_to_add = min(num_bytes, bytes_to_add);
5176                                 dest->reserved += bytes_to_add;
5177                                 if (dest->reserved >= dest->size)
5178                                         dest->full = 1;
5179                                 num_bytes -= bytes_to_add;
5180                         }
5181                         spin_unlock(&dest->lock);
5182                 }
5183                 if (num_bytes) {
5184                         spin_lock(&space_info->lock);
5185                         space_info->bytes_may_use -= num_bytes;
5186                         trace_btrfs_space_reservation(fs_info, "space_info",
5187                                         space_info->flags, num_bytes, 0);
5188                         spin_unlock(&space_info->lock);
5189                 }
5190         }
5191 }
5192
5193 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
5194                                    struct btrfs_block_rsv *dst, u64 num_bytes)
5195 {
5196         int ret;
5197
5198         ret = block_rsv_use_bytes(src, num_bytes);
5199         if (ret)
5200                 return ret;
5201
5202         block_rsv_add_bytes(dst, num_bytes, 1);
5203         return 0;
5204 }
5205
5206 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5207 {
5208         memset(rsv, 0, sizeof(*rsv));
5209         spin_lock_init(&rsv->lock);
5210         rsv->type = type;
5211 }
5212
5213 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5214                                               unsigned short type)
5215 {
5216         struct btrfs_block_rsv *block_rsv;
5217         struct btrfs_fs_info *fs_info = root->fs_info;
5218
5219         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5220         if (!block_rsv)
5221                 return NULL;
5222
5223         btrfs_init_block_rsv(block_rsv, type);
5224         block_rsv->space_info = __find_space_info(fs_info,
5225                                                   BTRFS_BLOCK_GROUP_METADATA);
5226         return block_rsv;
5227 }
5228
5229 void btrfs_free_block_rsv(struct btrfs_root *root,
5230                           struct btrfs_block_rsv *rsv)
5231 {
5232         if (!rsv)
5233                 return;
5234         btrfs_block_rsv_release(root, rsv, (u64)-1);
5235         kfree(rsv);
5236 }
5237
5238 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5239 {
5240         kfree(rsv);
5241 }
5242
5243 int btrfs_block_rsv_add(struct btrfs_root *root,
5244                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5245                         enum btrfs_reserve_flush_enum flush)
5246 {
5247         int ret;
5248
5249         if (num_bytes == 0)
5250                 return 0;
5251
5252         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5253         if (!ret) {
5254                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5255                 return 0;
5256         }
5257
5258         return ret;
5259 }
5260
5261 int btrfs_block_rsv_check(struct btrfs_root *root,
5262                           struct btrfs_block_rsv *block_rsv, int min_factor)
5263 {
5264         u64 num_bytes = 0;
5265         int ret = -ENOSPC;
5266
5267         if (!block_rsv)
5268                 return 0;
5269
5270         spin_lock(&block_rsv->lock);
5271         num_bytes = div_factor(block_rsv->size, min_factor);
5272         if (block_rsv->reserved >= num_bytes)
5273                 ret = 0;
5274         spin_unlock(&block_rsv->lock);
5275
5276         return ret;
5277 }
5278
5279 int btrfs_block_rsv_refill(struct btrfs_root *root,
5280                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5281                            enum btrfs_reserve_flush_enum flush)
5282 {
5283         u64 num_bytes = 0;
5284         int ret = -ENOSPC;
5285
5286         if (!block_rsv)
5287                 return 0;
5288
5289         spin_lock(&block_rsv->lock);
5290         num_bytes = min_reserved;
5291         if (block_rsv->reserved >= num_bytes)
5292                 ret = 0;
5293         else
5294                 num_bytes -= block_rsv->reserved;
5295         spin_unlock(&block_rsv->lock);
5296
5297         if (!ret)
5298                 return 0;
5299
5300         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5301         if (!ret) {
5302                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5303                 return 0;
5304         }
5305
5306         return ret;
5307 }
5308
5309 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
5310                             struct btrfs_block_rsv *dst_rsv,
5311                             u64 num_bytes)
5312 {
5313         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5314 }
5315
5316 void btrfs_block_rsv_release(struct btrfs_root *root,
5317                              struct btrfs_block_rsv *block_rsv,
5318                              u64 num_bytes)
5319 {
5320         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5321         if (global_rsv == block_rsv ||
5322             block_rsv->space_info != global_rsv->space_info)
5323                 global_rsv = NULL;
5324         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5325                                 num_bytes);
5326 }
5327
5328 /*
5329  * helper to calculate size of global block reservation.
5330  * the desired value is sum of space used by extent tree,
5331  * checksum tree and root tree
5332  */
5333 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
5334 {
5335         struct btrfs_space_info *sinfo;
5336         u64 num_bytes;
5337         u64 meta_used;
5338         u64 data_used;
5339         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
5340
5341         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
5342         spin_lock(&sinfo->lock);
5343         data_used = sinfo->bytes_used;
5344         spin_unlock(&sinfo->lock);
5345
5346         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5347         spin_lock(&sinfo->lock);
5348         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
5349                 data_used = 0;
5350         meta_used = sinfo->bytes_used;
5351         spin_unlock(&sinfo->lock);
5352
5353         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
5354                     csum_size * 2;
5355         num_bytes += div_u64(data_used + meta_used, 50);
5356
5357         if (num_bytes * 3 > meta_used)
5358                 num_bytes = div_u64(meta_used, 3);
5359
5360         return ALIGN(num_bytes, fs_info->extent_root->nodesize << 10);
5361 }
5362
5363 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5364 {
5365         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5366         struct btrfs_space_info *sinfo = block_rsv->space_info;
5367         u64 num_bytes;
5368
5369         num_bytes = calc_global_metadata_size(fs_info);
5370
5371         spin_lock(&sinfo->lock);
5372         spin_lock(&block_rsv->lock);
5373
5374         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5375
5376         if (block_rsv->reserved < block_rsv->size) {
5377                 num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5378                         sinfo->bytes_reserved + sinfo->bytes_readonly +
5379                         sinfo->bytes_may_use;
5380                 if (sinfo->total_bytes > num_bytes) {
5381                         num_bytes = sinfo->total_bytes - num_bytes;
5382                         num_bytes = min(num_bytes,
5383                                         block_rsv->size - block_rsv->reserved);
5384                         block_rsv->reserved += num_bytes;
5385                         sinfo->bytes_may_use += num_bytes;
5386                         trace_btrfs_space_reservation(fs_info, "space_info",
5387                                                       sinfo->flags, num_bytes,
5388                                                       1);
5389                 }
5390         } else if (block_rsv->reserved > block_rsv->size) {
5391                 num_bytes = block_rsv->reserved - block_rsv->size;
5392                 sinfo->bytes_may_use -= num_bytes;
5393                 trace_btrfs_space_reservation(fs_info, "space_info",
5394                                       sinfo->flags, num_bytes, 0);
5395                 block_rsv->reserved = block_rsv->size;
5396         }
5397
5398         if (block_rsv->reserved == block_rsv->size)
5399                 block_rsv->full = 1;
5400         else
5401                 block_rsv->full = 0;
5402
5403         spin_unlock(&block_rsv->lock);
5404         spin_unlock(&sinfo->lock);
5405 }
5406
5407 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5408 {
5409         struct btrfs_space_info *space_info;
5410
5411         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5412         fs_info->chunk_block_rsv.space_info = space_info;
5413
5414         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5415         fs_info->global_block_rsv.space_info = space_info;
5416         fs_info->delalloc_block_rsv.space_info = space_info;
5417         fs_info->trans_block_rsv.space_info = space_info;
5418         fs_info->empty_block_rsv.space_info = space_info;
5419         fs_info->delayed_block_rsv.space_info = space_info;
5420
5421         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5422         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5423         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5424         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5425         if (fs_info->quota_root)
5426                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5427         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5428
5429         update_global_block_rsv(fs_info);
5430 }
5431
5432 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5433 {
5434         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5435                                 (u64)-1);
5436         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5437         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5438         WARN_ON(fs_info->trans_block_rsv.size > 0);
5439         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5440         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5441         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5442         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5443         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5444 }
5445
5446 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5447                                   struct btrfs_root *root)
5448 {
5449         if (!trans->block_rsv)
5450                 return;
5451
5452         if (!trans->bytes_reserved)
5453                 return;
5454
5455         trace_btrfs_space_reservation(root->fs_info, "transaction",
5456                                       trans->transid, trans->bytes_reserved, 0);
5457         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5458         trans->bytes_reserved = 0;
5459 }
5460
5461 /*
5462  * To be called after all the new block groups attached to the transaction
5463  * handle have been created (btrfs_create_pending_block_groups()).
5464  */
5465 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5466 {
5467         struct btrfs_fs_info *fs_info = trans->root->fs_info;
5468
5469         if (!trans->chunk_bytes_reserved)
5470                 return;
5471
5472         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5473
5474         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5475                                 trans->chunk_bytes_reserved);
5476         trans->chunk_bytes_reserved = 0;
5477 }
5478
5479 /* Can only return 0 or -ENOSPC */
5480 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5481                                   struct inode *inode)
5482 {
5483         struct btrfs_root *root = BTRFS_I(inode)->root;
5484         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
5485         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5486
5487         /*
5488          * We need to hold space in order to delete our orphan item once we've
5489          * added it, so this takes the reservation so we can release it later
5490          * when we are truly done with the orphan item.
5491          */
5492         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5493         trace_btrfs_space_reservation(root->fs_info, "orphan",
5494                                       btrfs_ino(inode), num_bytes, 1);
5495         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5496 }
5497
5498 void btrfs_orphan_release_metadata(struct inode *inode)
5499 {
5500         struct btrfs_root *root = BTRFS_I(inode)->root;
5501         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5502         trace_btrfs_space_reservation(root->fs_info, "orphan",
5503                                       btrfs_ino(inode), num_bytes, 0);
5504         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5505 }
5506
5507 /*
5508  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5509  * root: the root of the parent directory
5510  * rsv: block reservation
5511  * items: the number of items that we need do reservation
5512  * qgroup_reserved: used to return the reserved size in qgroup
5513  *
5514  * This function is used to reserve the space for snapshot/subvolume
5515  * creation and deletion. Those operations are different with the
5516  * common file/directory operations, they change two fs/file trees
5517  * and root tree, the number of items that the qgroup reserves is
5518  * different with the free space reservation. So we can not use
5519  * the space reseravtion mechanism in start_transaction().
5520  */
5521 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5522                                      struct btrfs_block_rsv *rsv,
5523                                      int items,
5524                                      u64 *qgroup_reserved,
5525                                      bool use_global_rsv)
5526 {
5527         u64 num_bytes;
5528         int ret;
5529         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5530
5531         if (root->fs_info->quota_enabled) {
5532                 /* One for parent inode, two for dir entries */
5533                 num_bytes = 3 * root->nodesize;
5534                 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5535                 if (ret)
5536                         return ret;
5537         } else {
5538                 num_bytes = 0;
5539         }
5540
5541         *qgroup_reserved = num_bytes;
5542
5543         num_bytes = btrfs_calc_trans_metadata_size(root, items);
5544         rsv->space_info = __find_space_info(root->fs_info,
5545                                             BTRFS_BLOCK_GROUP_METADATA);
5546         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5547                                   BTRFS_RESERVE_FLUSH_ALL);
5548
5549         if (ret == -ENOSPC && use_global_rsv)
5550                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
5551
5552         if (ret && *qgroup_reserved)
5553                 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5554
5555         return ret;
5556 }
5557
5558 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5559                                       struct btrfs_block_rsv *rsv,
5560                                       u64 qgroup_reserved)
5561 {
5562         btrfs_block_rsv_release(root, rsv, (u64)-1);
5563 }
5564
5565 /**
5566  * drop_outstanding_extent - drop an outstanding extent
5567  * @inode: the inode we're dropping the extent for
5568  * @num_bytes: the number of bytes we're relaseing.
5569  *
5570  * This is called when we are freeing up an outstanding extent, either called
5571  * after an error or after an extent is written.  This will return the number of
5572  * reserved extents that need to be freed.  This must be called with
5573  * BTRFS_I(inode)->lock held.
5574  */
5575 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5576 {
5577         unsigned drop_inode_space = 0;
5578         unsigned dropped_extents = 0;
5579         unsigned num_extents = 0;
5580
5581         num_extents = (unsigned)div64_u64(num_bytes +
5582                                           BTRFS_MAX_EXTENT_SIZE - 1,
5583                                           BTRFS_MAX_EXTENT_SIZE);
5584         ASSERT(num_extents);
5585         ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5586         BTRFS_I(inode)->outstanding_extents -= num_extents;
5587
5588         if (BTRFS_I(inode)->outstanding_extents == 0 &&
5589             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5590                                &BTRFS_I(inode)->runtime_flags))
5591                 drop_inode_space = 1;
5592
5593         /*
5594          * If we have more or the same amount of outsanding extents than we have
5595          * reserved then we need to leave the reserved extents count alone.
5596          */
5597         if (BTRFS_I(inode)->outstanding_extents >=
5598             BTRFS_I(inode)->reserved_extents)
5599                 return drop_inode_space;
5600
5601         dropped_extents = BTRFS_I(inode)->reserved_extents -
5602                 BTRFS_I(inode)->outstanding_extents;
5603         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5604         return dropped_extents + drop_inode_space;
5605 }
5606
5607 /**
5608  * calc_csum_metadata_size - return the amount of metada space that must be
5609  *      reserved/free'd for the given bytes.
5610  * @inode: the inode we're manipulating
5611  * @num_bytes: the number of bytes in question
5612  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5613  *
5614  * This adjusts the number of csum_bytes in the inode and then returns the
5615  * correct amount of metadata that must either be reserved or freed.  We
5616  * calculate how many checksums we can fit into one leaf and then divide the
5617  * number of bytes that will need to be checksumed by this value to figure out
5618  * how many checksums will be required.  If we are adding bytes then the number
5619  * may go up and we will return the number of additional bytes that must be
5620  * reserved.  If it is going down we will return the number of bytes that must
5621  * be freed.
5622  *
5623  * This must be called with BTRFS_I(inode)->lock held.
5624  */
5625 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5626                                    int reserve)
5627 {
5628         struct btrfs_root *root = BTRFS_I(inode)->root;
5629         u64 old_csums, num_csums;
5630
5631         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5632             BTRFS_I(inode)->csum_bytes == 0)
5633                 return 0;
5634
5635         old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5636         if (reserve)
5637                 BTRFS_I(inode)->csum_bytes += num_bytes;
5638         else
5639                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5640         num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5641
5642         /* No change, no need to reserve more */
5643         if (old_csums == num_csums)
5644                 return 0;
5645
5646         if (reserve)
5647                 return btrfs_calc_trans_metadata_size(root,
5648                                                       num_csums - old_csums);
5649
5650         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5651 }
5652
5653 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5654 {
5655         struct btrfs_root *root = BTRFS_I(inode)->root;
5656         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5657         u64 to_reserve = 0;
5658         u64 csum_bytes;
5659         unsigned nr_extents = 0;
5660         int extra_reserve = 0;
5661         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5662         int ret = 0;
5663         bool delalloc_lock = true;
5664         u64 to_free = 0;
5665         unsigned dropped;
5666
5667         /* If we are a free space inode we need to not flush since we will be in
5668          * the middle of a transaction commit.  We also don't need the delalloc
5669          * mutex since we won't race with anybody.  We need this mostly to make
5670          * lockdep shut its filthy mouth.
5671          */
5672         if (btrfs_is_free_space_inode(inode)) {
5673                 flush = BTRFS_RESERVE_NO_FLUSH;
5674                 delalloc_lock = false;
5675         }
5676
5677         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5678             btrfs_transaction_in_commit(root->fs_info))
5679                 schedule_timeout(1);
5680
5681         if (delalloc_lock)
5682                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5683
5684         num_bytes = ALIGN(num_bytes, root->sectorsize);
5685
5686         spin_lock(&BTRFS_I(inode)->lock);
5687         nr_extents = (unsigned)div64_u64(num_bytes +
5688                                          BTRFS_MAX_EXTENT_SIZE - 1,
5689                                          BTRFS_MAX_EXTENT_SIZE);
5690         BTRFS_I(inode)->outstanding_extents += nr_extents;
5691         nr_extents = 0;
5692
5693         if (BTRFS_I(inode)->outstanding_extents >
5694             BTRFS_I(inode)->reserved_extents)
5695                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5696                         BTRFS_I(inode)->reserved_extents;
5697
5698         /*
5699          * Add an item to reserve for updating the inode when we complete the
5700          * delalloc io.
5701          */
5702         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5703                       &BTRFS_I(inode)->runtime_flags)) {
5704                 nr_extents++;
5705                 extra_reserve = 1;
5706         }
5707
5708         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5709         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5710         csum_bytes = BTRFS_I(inode)->csum_bytes;
5711         spin_unlock(&BTRFS_I(inode)->lock);
5712
5713         if (root->fs_info->quota_enabled) {
5714                 ret = btrfs_qgroup_reserve_meta(root,
5715                                 nr_extents * root->nodesize);
5716                 if (ret)
5717                         goto out_fail;
5718         }
5719
5720         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5721         if (unlikely(ret)) {
5722                 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5723                 goto out_fail;
5724         }
5725
5726         spin_lock(&BTRFS_I(inode)->lock);
5727         if (extra_reserve) {
5728                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5729                         &BTRFS_I(inode)->runtime_flags);
5730                 nr_extents--;
5731         }
5732         BTRFS_I(inode)->reserved_extents += nr_extents;
5733         spin_unlock(&BTRFS_I(inode)->lock);
5734
5735         if (delalloc_lock)
5736                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5737
5738         if (to_reserve)
5739                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5740                                               btrfs_ino(inode), to_reserve, 1);
5741         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5742
5743         return 0;
5744
5745 out_fail:
5746         spin_lock(&BTRFS_I(inode)->lock);
5747         dropped = drop_outstanding_extent(inode, num_bytes);
5748         /*
5749          * If the inodes csum_bytes is the same as the original
5750          * csum_bytes then we know we haven't raced with any free()ers
5751          * so we can just reduce our inodes csum bytes and carry on.
5752          */
5753         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5754                 calc_csum_metadata_size(inode, num_bytes, 0);
5755         } else {
5756                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5757                 u64 bytes;
5758
5759                 /*
5760                  * This is tricky, but first we need to figure out how much we
5761                  * free'd from any free-ers that occurred during this
5762                  * reservation, so we reset ->csum_bytes to the csum_bytes
5763                  * before we dropped our lock, and then call the free for the
5764                  * number of bytes that were freed while we were trying our
5765                  * reservation.
5766                  */
5767                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5768                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5769                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5770
5771
5772                 /*
5773                  * Now we need to see how much we would have freed had we not
5774                  * been making this reservation and our ->csum_bytes were not
5775                  * artificially inflated.
5776                  */
5777                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5778                 bytes = csum_bytes - orig_csum_bytes;
5779                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5780
5781                 /*
5782                  * Now reset ->csum_bytes to what it should be.  If bytes is
5783                  * more than to_free then we would have free'd more space had we
5784                  * not had an artificially high ->csum_bytes, so we need to free
5785                  * the remainder.  If bytes is the same or less then we don't
5786                  * need to do anything, the other free-ers did the correct
5787                  * thing.
5788                  */
5789                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5790                 if (bytes > to_free)
5791                         to_free = bytes - to_free;
5792                 else
5793                         to_free = 0;
5794         }
5795         spin_unlock(&BTRFS_I(inode)->lock);
5796         if (dropped)
5797                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5798
5799         if (to_free) {
5800                 btrfs_block_rsv_release(root, block_rsv, to_free);
5801                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5802                                               btrfs_ino(inode), to_free, 0);
5803         }
5804         if (delalloc_lock)
5805                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5806         return ret;
5807 }
5808
5809 /**
5810  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5811  * @inode: the inode to release the reservation for
5812  * @num_bytes: the number of bytes we're releasing
5813  *
5814  * This will release the metadata reservation for an inode.  This can be called
5815  * once we complete IO for a given set of bytes to release their metadata
5816  * reservations.
5817  */
5818 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5819 {
5820         struct btrfs_root *root = BTRFS_I(inode)->root;
5821         u64 to_free = 0;
5822         unsigned dropped;
5823
5824         num_bytes = ALIGN(num_bytes, root->sectorsize);
5825         spin_lock(&BTRFS_I(inode)->lock);
5826         dropped = drop_outstanding_extent(inode, num_bytes);
5827
5828         if (num_bytes)
5829                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5830         spin_unlock(&BTRFS_I(inode)->lock);
5831         if (dropped > 0)
5832                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5833
5834         if (btrfs_test_is_dummy_root(root))
5835                 return;
5836
5837         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5838                                       btrfs_ino(inode), to_free, 0);
5839
5840         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5841                                 to_free);
5842 }
5843
5844 /**
5845  * btrfs_delalloc_reserve_space - reserve data and metadata space for
5846  * delalloc
5847  * @inode: inode we're writing to
5848  * @start: start range we are writing to
5849  * @len: how long the range we are writing to
5850  *
5851  * TODO: This function will finally replace old btrfs_delalloc_reserve_space()
5852  *
5853  * This will do the following things
5854  *
5855  * o reserve space in data space info for num bytes
5856  *   and reserve precious corresponding qgroup space
5857  *   (Done in check_data_free_space)
5858  *
5859  * o reserve space for metadata space, based on the number of outstanding
5860  *   extents and how much csums will be needed
5861  *   also reserve metadata space in a per root over-reserve method.
5862  * o add to the inodes->delalloc_bytes
5863  * o add it to the fs_info's delalloc inodes list.
5864  *   (Above 3 all done in delalloc_reserve_metadata)
5865  *
5866  * Return 0 for success
5867  * Return <0 for error(-ENOSPC or -EQUOT)
5868  */
5869 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
5870 {
5871         int ret;
5872
5873         ret = btrfs_check_data_free_space(inode, start, len);
5874         if (ret < 0)
5875                 return ret;
5876         ret = btrfs_delalloc_reserve_metadata(inode, len);
5877         if (ret < 0)
5878                 btrfs_free_reserved_data_space(inode, start, len);
5879         return ret;
5880 }
5881
5882 /**
5883  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5884  * @inode: inode we're releasing space for
5885  * @start: start position of the space already reserved
5886  * @len: the len of the space already reserved
5887  *
5888  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5889  * called in the case that we don't need the metadata AND data reservations
5890  * anymore.  So if there is an error or we insert an inline extent.
5891  *
5892  * This function will release the metadata space that was not used and will
5893  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5894  * list if there are no delalloc bytes left.
5895  * Also it will handle the qgroup reserved space.
5896  */
5897 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
5898 {
5899         btrfs_delalloc_release_metadata(inode, len);
5900         btrfs_free_reserved_data_space(inode, start, len);
5901 }
5902
5903 static int update_block_group(struct btrfs_trans_handle *trans,
5904                               struct btrfs_root *root, u64 bytenr,
5905                               u64 num_bytes, int alloc)
5906 {
5907         struct btrfs_block_group_cache *cache = NULL;
5908         struct btrfs_fs_info *info = root->fs_info;
5909         u64 total = num_bytes;
5910         u64 old_val;
5911         u64 byte_in_group;
5912         int factor;
5913
5914         /* block accounting for super block */
5915         spin_lock(&info->delalloc_root_lock);
5916         old_val = btrfs_super_bytes_used(info->super_copy);
5917         if (alloc)
5918                 old_val += num_bytes;
5919         else
5920                 old_val -= num_bytes;
5921         btrfs_set_super_bytes_used(info->super_copy, old_val);
5922         spin_unlock(&info->delalloc_root_lock);
5923
5924         while (total) {
5925                 cache = btrfs_lookup_block_group(info, bytenr);
5926                 if (!cache)
5927                         return -ENOENT;
5928                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5929                                     BTRFS_BLOCK_GROUP_RAID1 |
5930                                     BTRFS_BLOCK_GROUP_RAID10))
5931                         factor = 2;
5932                 else
5933                         factor = 1;
5934                 /*
5935                  * If this block group has free space cache written out, we
5936                  * need to make sure to load it if we are removing space.  This
5937                  * is because we need the unpinning stage to actually add the
5938                  * space back to the block group, otherwise we will leak space.
5939                  */
5940                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5941                         cache_block_group(cache, 1);
5942
5943                 byte_in_group = bytenr - cache->key.objectid;
5944                 WARN_ON(byte_in_group > cache->key.offset);
5945
5946                 spin_lock(&cache->space_info->lock);
5947                 spin_lock(&cache->lock);
5948
5949                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5950                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5951                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5952
5953                 old_val = btrfs_block_group_used(&cache->item);
5954                 num_bytes = min(total, cache->key.offset - byte_in_group);
5955                 if (alloc) {
5956                         old_val += num_bytes;
5957                         btrfs_set_block_group_used(&cache->item, old_val);
5958                         cache->reserved -= num_bytes;
5959                         cache->space_info->bytes_reserved -= num_bytes;
5960                         cache->space_info->bytes_used += num_bytes;
5961                         cache->space_info->disk_used += num_bytes * factor;
5962                         spin_unlock(&cache->lock);
5963                         spin_unlock(&cache->space_info->lock);
5964                 } else {
5965                         old_val -= num_bytes;
5966                         btrfs_set_block_group_used(&cache->item, old_val);
5967                         cache->pinned += num_bytes;
5968                         cache->space_info->bytes_pinned += num_bytes;
5969                         cache->space_info->bytes_used -= num_bytes;
5970                         cache->space_info->disk_used -= num_bytes * factor;
5971                         spin_unlock(&cache->lock);
5972                         spin_unlock(&cache->space_info->lock);
5973
5974                         set_extent_dirty(info->pinned_extents,
5975                                          bytenr, bytenr + num_bytes - 1,
5976                                          GFP_NOFS | __GFP_NOFAIL);
5977                 }
5978
5979                 spin_lock(&trans->transaction->dirty_bgs_lock);
5980                 if (list_empty(&cache->dirty_list)) {
5981                         list_add_tail(&cache->dirty_list,
5982                                       &trans->transaction->dirty_bgs);
5983                                 trans->transaction->num_dirty_bgs++;
5984                         btrfs_get_block_group(cache);
5985                 }
5986                 spin_unlock(&trans->transaction->dirty_bgs_lock);
5987
5988                 /*
5989                  * No longer have used bytes in this block group, queue it for
5990                  * deletion. We do this after adding the block group to the
5991                  * dirty list to avoid races between cleaner kthread and space
5992                  * cache writeout.
5993                  */
5994                 if (!alloc && old_val == 0) {
5995                         spin_lock(&info->unused_bgs_lock);
5996                         if (list_empty(&cache->bg_list)) {
5997                                 btrfs_get_block_group(cache);
5998                                 list_add_tail(&cache->bg_list,
5999                                               &info->unused_bgs);
6000                         }
6001                         spin_unlock(&info->unused_bgs_lock);
6002                 }
6003
6004                 btrfs_put_block_group(cache);
6005                 total -= num_bytes;
6006                 bytenr += num_bytes;
6007         }
6008         return 0;
6009 }
6010
6011 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
6012 {
6013         struct btrfs_block_group_cache *cache;
6014         u64 bytenr;
6015
6016         spin_lock(&root->fs_info->block_group_cache_lock);
6017         bytenr = root->fs_info->first_logical_byte;
6018         spin_unlock(&root->fs_info->block_group_cache_lock);
6019
6020         if (bytenr < (u64)-1)
6021                 return bytenr;
6022
6023         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
6024         if (!cache)
6025                 return 0;
6026
6027         bytenr = cache->key.objectid;
6028         btrfs_put_block_group(cache);
6029
6030         return bytenr;
6031 }
6032
6033 static int pin_down_extent(struct btrfs_root *root,
6034                            struct btrfs_block_group_cache *cache,
6035                            u64 bytenr, u64 num_bytes, int reserved)
6036 {
6037         spin_lock(&cache->space_info->lock);
6038         spin_lock(&cache->lock);
6039         cache->pinned += num_bytes;
6040         cache->space_info->bytes_pinned += num_bytes;
6041         if (reserved) {
6042                 cache->reserved -= num_bytes;
6043                 cache->space_info->bytes_reserved -= num_bytes;
6044         }
6045         spin_unlock(&cache->lock);
6046         spin_unlock(&cache->space_info->lock);
6047
6048         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
6049                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6050         if (reserved)
6051                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
6052         return 0;
6053 }
6054
6055 /*
6056  * this function must be called within transaction
6057  */
6058 int btrfs_pin_extent(struct btrfs_root *root,
6059                      u64 bytenr, u64 num_bytes, int reserved)
6060 {
6061         struct btrfs_block_group_cache *cache;
6062
6063         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6064         BUG_ON(!cache); /* Logic error */
6065
6066         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
6067
6068         btrfs_put_block_group(cache);
6069         return 0;
6070 }
6071
6072 /*
6073  * this function must be called within transaction
6074  */
6075 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
6076                                     u64 bytenr, u64 num_bytes)
6077 {
6078         struct btrfs_block_group_cache *cache;
6079         int ret;
6080
6081         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6082         if (!cache)
6083                 return -EINVAL;
6084
6085         /*
6086          * pull in the free space cache (if any) so that our pin
6087          * removes the free space from the cache.  We have load_only set
6088          * to one because the slow code to read in the free extents does check
6089          * the pinned extents.
6090          */
6091         cache_block_group(cache, 1);
6092
6093         pin_down_extent(root, cache, bytenr, num_bytes, 0);
6094
6095         /* remove us from the free space cache (if we're there at all) */
6096         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6097         btrfs_put_block_group(cache);
6098         return ret;
6099 }
6100
6101 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
6102 {
6103         int ret;
6104         struct btrfs_block_group_cache *block_group;
6105         struct btrfs_caching_control *caching_ctl;
6106
6107         block_group = btrfs_lookup_block_group(root->fs_info, start);
6108         if (!block_group)
6109                 return -EINVAL;
6110
6111         cache_block_group(block_group, 0);
6112         caching_ctl = get_caching_control(block_group);
6113
6114         if (!caching_ctl) {
6115                 /* Logic error */
6116                 BUG_ON(!block_group_cache_done(block_group));
6117                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6118         } else {
6119                 mutex_lock(&caching_ctl->mutex);
6120
6121                 if (start >= caching_ctl->progress) {
6122                         ret = add_excluded_extent(root, start, num_bytes);
6123                 } else if (start + num_bytes <= caching_ctl->progress) {
6124                         ret = btrfs_remove_free_space(block_group,
6125                                                       start, num_bytes);
6126                 } else {
6127                         num_bytes = caching_ctl->progress - start;
6128                         ret = btrfs_remove_free_space(block_group,
6129                                                       start, num_bytes);
6130                         if (ret)
6131                                 goto out_lock;
6132
6133                         num_bytes = (start + num_bytes) -
6134                                 caching_ctl->progress;
6135                         start = caching_ctl->progress;
6136                         ret = add_excluded_extent(root, start, num_bytes);
6137                 }
6138 out_lock:
6139                 mutex_unlock(&caching_ctl->mutex);
6140                 put_caching_control(caching_ctl);
6141         }
6142         btrfs_put_block_group(block_group);
6143         return ret;
6144 }
6145
6146 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6147                                  struct extent_buffer *eb)
6148 {
6149         struct btrfs_file_extent_item *item;
6150         struct btrfs_key key;
6151         int found_type;
6152         int i;
6153
6154         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6155                 return 0;
6156
6157         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6158                 btrfs_item_key_to_cpu(eb, &key, i);
6159                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6160                         continue;
6161                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6162                 found_type = btrfs_file_extent_type(eb, item);
6163                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6164                         continue;
6165                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6166                         continue;
6167                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6168                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6169                 __exclude_logged_extent(log, key.objectid, key.offset);
6170         }
6171
6172         return 0;
6173 }
6174
6175 /**
6176  * btrfs_update_reserved_bytes - update the block_group and space info counters
6177  * @cache:      The cache we are manipulating
6178  * @num_bytes:  The number of bytes in question
6179  * @reserve:    One of the reservation enums
6180  * @delalloc:   The blocks are allocated for the delalloc write
6181  *
6182  * This is called by the allocator when it reserves space, or by somebody who is
6183  * freeing space that was never actually used on disk.  For example if you
6184  * reserve some space for a new leaf in transaction A and before transaction A
6185  * commits you free that leaf, you call this with reserve set to 0 in order to
6186  * clear the reservation.
6187  *
6188  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
6189  * ENOSPC accounting.  For data we handle the reservation through clearing the
6190  * delalloc bits in the io_tree.  We have to do this since we could end up
6191  * allocating less disk space for the amount of data we have reserved in the
6192  * case of compression.
6193  *
6194  * If this is a reservation and the block group has become read only we cannot
6195  * make the reservation and return -EAGAIN, otherwise this function always
6196  * succeeds.
6197  */
6198 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
6199                                        u64 num_bytes, int reserve, int delalloc)
6200 {
6201         struct btrfs_space_info *space_info = cache->space_info;
6202         int ret = 0;
6203
6204         spin_lock(&space_info->lock);
6205         spin_lock(&cache->lock);
6206         if (reserve != RESERVE_FREE) {
6207                 if (cache->ro) {
6208                         ret = -EAGAIN;
6209                 } else {
6210                         cache->reserved += num_bytes;
6211                         space_info->bytes_reserved += num_bytes;
6212                         if (reserve == RESERVE_ALLOC) {
6213                                 trace_btrfs_space_reservation(cache->fs_info,
6214                                                 "space_info", space_info->flags,
6215                                                 num_bytes, 0);
6216                                 space_info->bytes_may_use -= num_bytes;
6217                         }
6218
6219                         if (delalloc)
6220                                 cache->delalloc_bytes += num_bytes;
6221                 }
6222         } else {
6223                 if (cache->ro)
6224                         space_info->bytes_readonly += num_bytes;
6225                 cache->reserved -= num_bytes;
6226                 space_info->bytes_reserved -= num_bytes;
6227
6228                 if (delalloc)
6229                         cache->delalloc_bytes -= num_bytes;
6230         }
6231         spin_unlock(&cache->lock);
6232         spin_unlock(&space_info->lock);
6233         return ret;
6234 }
6235
6236 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6237                                 struct btrfs_root *root)
6238 {
6239         struct btrfs_fs_info *fs_info = root->fs_info;
6240         struct btrfs_caching_control *next;
6241         struct btrfs_caching_control *caching_ctl;
6242         struct btrfs_block_group_cache *cache;
6243
6244         down_write(&fs_info->commit_root_sem);
6245
6246         list_for_each_entry_safe(caching_ctl, next,
6247                                  &fs_info->caching_block_groups, list) {
6248                 cache = caching_ctl->block_group;
6249                 if (block_group_cache_done(cache)) {
6250                         cache->last_byte_to_unpin = (u64)-1;
6251                         list_del_init(&caching_ctl->list);
6252                         put_caching_control(caching_ctl);
6253                 } else {
6254                         cache->last_byte_to_unpin = caching_ctl->progress;
6255                 }
6256         }
6257
6258         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6259                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6260         else
6261                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6262
6263         up_write(&fs_info->commit_root_sem);
6264
6265         update_global_block_rsv(fs_info);
6266 }
6267
6268 /*
6269  * Returns the free cluster for the given space info and sets empty_cluster to
6270  * what it should be based on the mount options.
6271  */
6272 static struct btrfs_free_cluster *
6273 fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
6274                    u64 *empty_cluster)
6275 {
6276         struct btrfs_free_cluster *ret = NULL;
6277         bool ssd = btrfs_test_opt(root, SSD);
6278
6279         *empty_cluster = 0;
6280         if (btrfs_mixed_space_info(space_info))
6281                 return ret;
6282
6283         if (ssd)
6284                 *empty_cluster = SZ_2M;
6285         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6286                 ret = &root->fs_info->meta_alloc_cluster;
6287                 if (!ssd)
6288                         *empty_cluster = SZ_64K;
6289         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6290                 ret = &root->fs_info->data_alloc_cluster;
6291         }
6292
6293         return ret;
6294 }
6295
6296 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6297                               const bool return_free_space)
6298 {
6299         struct btrfs_fs_info *fs_info = root->fs_info;
6300         struct btrfs_block_group_cache *cache = NULL;
6301         struct btrfs_space_info *space_info;
6302         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6303         struct btrfs_free_cluster *cluster = NULL;
6304         u64 len;
6305         u64 total_unpinned = 0;
6306         u64 empty_cluster = 0;
6307         bool readonly;
6308
6309         while (start <= end) {
6310                 readonly = false;
6311                 if (!cache ||
6312                     start >= cache->key.objectid + cache->key.offset) {
6313                         if (cache)
6314                                 btrfs_put_block_group(cache);
6315                         total_unpinned = 0;
6316                         cache = btrfs_lookup_block_group(fs_info, start);
6317                         BUG_ON(!cache); /* Logic error */
6318
6319                         cluster = fetch_cluster_info(root,
6320                                                      cache->space_info,
6321                                                      &empty_cluster);
6322                         empty_cluster <<= 1;
6323                 }
6324
6325                 len = cache->key.objectid + cache->key.offset - start;
6326                 len = min(len, end + 1 - start);
6327
6328                 if (start < cache->last_byte_to_unpin) {
6329                         len = min(len, cache->last_byte_to_unpin - start);
6330                         if (return_free_space)
6331                                 btrfs_add_free_space(cache, start, len);
6332                 }
6333
6334                 start += len;
6335                 total_unpinned += len;
6336                 space_info = cache->space_info;
6337
6338                 /*
6339                  * If this space cluster has been marked as fragmented and we've
6340                  * unpinned enough in this block group to potentially allow a
6341                  * cluster to be created inside of it go ahead and clear the
6342                  * fragmented check.
6343                  */
6344                 if (cluster && cluster->fragmented &&
6345                     total_unpinned > empty_cluster) {
6346                         spin_lock(&cluster->lock);
6347                         cluster->fragmented = 0;
6348                         spin_unlock(&cluster->lock);
6349                 }
6350
6351                 spin_lock(&space_info->lock);
6352                 spin_lock(&cache->lock);
6353                 cache->pinned -= len;
6354                 space_info->bytes_pinned -= len;
6355                 space_info->max_extent_size = 0;
6356                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6357                 if (cache->ro) {
6358                         space_info->bytes_readonly += len;
6359                         readonly = true;
6360                 }
6361                 spin_unlock(&cache->lock);
6362                 if (!readonly && global_rsv->space_info == space_info) {
6363                         spin_lock(&global_rsv->lock);
6364                         if (!global_rsv->full) {
6365                                 len = min(len, global_rsv->size -
6366                                           global_rsv->reserved);
6367                                 global_rsv->reserved += len;
6368                                 space_info->bytes_may_use += len;
6369                                 if (global_rsv->reserved >= global_rsv->size)
6370                                         global_rsv->full = 1;
6371                         }
6372                         spin_unlock(&global_rsv->lock);
6373                 }
6374                 spin_unlock(&space_info->lock);
6375         }
6376
6377         if (cache)
6378                 btrfs_put_block_group(cache);
6379         return 0;
6380 }
6381
6382 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6383                                struct btrfs_root *root)
6384 {
6385         struct btrfs_fs_info *fs_info = root->fs_info;
6386         struct btrfs_block_group_cache *block_group, *tmp;
6387         struct list_head *deleted_bgs;
6388         struct extent_io_tree *unpin;
6389         u64 start;
6390         u64 end;
6391         int ret;
6392
6393         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6394                 unpin = &fs_info->freed_extents[1];
6395         else
6396                 unpin = &fs_info->freed_extents[0];
6397
6398         while (!trans->aborted) {
6399                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6400                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6401                                             EXTENT_DIRTY, NULL);
6402                 if (ret) {
6403                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6404                         break;
6405                 }
6406
6407                 if (btrfs_test_opt(root, DISCARD))
6408                         ret = btrfs_discard_extent(root, start,
6409                                                    end + 1 - start, NULL);
6410
6411                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
6412                 unpin_extent_range(root, start, end, true);
6413                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6414                 cond_resched();
6415         }
6416
6417         /*
6418          * Transaction is finished.  We don't need the lock anymore.  We
6419          * do need to clean up the block groups in case of a transaction
6420          * abort.
6421          */
6422         deleted_bgs = &trans->transaction->deleted_bgs;
6423         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6424                 u64 trimmed = 0;
6425
6426                 ret = -EROFS;
6427                 if (!trans->aborted)
6428                         ret = btrfs_discard_extent(root,
6429                                                    block_group->key.objectid,
6430                                                    block_group->key.offset,
6431                                                    &trimmed);
6432
6433                 list_del_init(&block_group->bg_list);
6434                 btrfs_put_block_group_trimming(block_group);
6435                 btrfs_put_block_group(block_group);
6436
6437                 if (ret) {
6438                         const char *errstr = btrfs_decode_error(ret);
6439                         btrfs_warn(fs_info,
6440                                    "Discard failed while removing blockgroup: errno=%d %s\n",
6441                                    ret, errstr);
6442                 }
6443         }
6444
6445         return 0;
6446 }
6447
6448 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6449                              u64 owner, u64 root_objectid)
6450 {
6451         struct btrfs_space_info *space_info;
6452         u64 flags;
6453
6454         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6455                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6456                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
6457                 else
6458                         flags = BTRFS_BLOCK_GROUP_METADATA;
6459         } else {
6460                 flags = BTRFS_BLOCK_GROUP_DATA;
6461         }
6462
6463         space_info = __find_space_info(fs_info, flags);
6464         BUG_ON(!space_info); /* Logic bug */
6465         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6466 }
6467
6468
6469 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6470                                 struct btrfs_root *root,
6471                                 struct btrfs_delayed_ref_node *node, u64 parent,
6472                                 u64 root_objectid, u64 owner_objectid,
6473                                 u64 owner_offset, int refs_to_drop,
6474                                 struct btrfs_delayed_extent_op *extent_op)
6475 {
6476         struct btrfs_key key;
6477         struct btrfs_path *path;
6478         struct btrfs_fs_info *info = root->fs_info;
6479         struct btrfs_root *extent_root = info->extent_root;
6480         struct extent_buffer *leaf;
6481         struct btrfs_extent_item *ei;
6482         struct btrfs_extent_inline_ref *iref;
6483         int ret;
6484         int is_data;
6485         int extent_slot = 0;
6486         int found_extent = 0;
6487         int num_to_del = 1;
6488         u32 item_size;
6489         u64 refs;
6490         u64 bytenr = node->bytenr;
6491         u64 num_bytes = node->num_bytes;
6492         int last_ref = 0;
6493         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6494                                                  SKINNY_METADATA);
6495
6496         path = btrfs_alloc_path();
6497         if (!path)
6498                 return -ENOMEM;
6499
6500         path->reada = READA_FORWARD;
6501         path->leave_spinning = 1;
6502
6503         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6504         BUG_ON(!is_data && refs_to_drop != 1);
6505
6506         if (is_data)
6507                 skinny_metadata = 0;
6508
6509         ret = lookup_extent_backref(trans, extent_root, path, &iref,
6510                                     bytenr, num_bytes, parent,
6511                                     root_objectid, owner_objectid,
6512                                     owner_offset);
6513         if (ret == 0) {
6514                 extent_slot = path->slots[0];
6515                 while (extent_slot >= 0) {
6516                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6517                                               extent_slot);
6518                         if (key.objectid != bytenr)
6519                                 break;
6520                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6521                             key.offset == num_bytes) {
6522                                 found_extent = 1;
6523                                 break;
6524                         }
6525                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6526                             key.offset == owner_objectid) {
6527                                 found_extent = 1;
6528                                 break;
6529                         }
6530                         if (path->slots[0] - extent_slot > 5)
6531                                 break;
6532                         extent_slot--;
6533                 }
6534 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6535                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6536                 if (found_extent && item_size < sizeof(*ei))
6537                         found_extent = 0;
6538 #endif
6539                 if (!found_extent) {
6540                         BUG_ON(iref);
6541                         ret = remove_extent_backref(trans, extent_root, path,
6542                                                     NULL, refs_to_drop,
6543                                                     is_data, &last_ref);
6544                         if (ret) {
6545                                 btrfs_abort_transaction(trans, extent_root, ret);
6546                                 goto out;
6547                         }
6548                         btrfs_release_path(path);
6549                         path->leave_spinning = 1;
6550
6551                         key.objectid = bytenr;
6552                         key.type = BTRFS_EXTENT_ITEM_KEY;
6553                         key.offset = num_bytes;
6554
6555                         if (!is_data && skinny_metadata) {
6556                                 key.type = BTRFS_METADATA_ITEM_KEY;
6557                                 key.offset = owner_objectid;
6558                         }
6559
6560                         ret = btrfs_search_slot(trans, extent_root,
6561                                                 &key, path, -1, 1);
6562                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6563                                 /*
6564                                  * Couldn't find our skinny metadata item,
6565                                  * see if we have ye olde extent item.
6566                                  */
6567                                 path->slots[0]--;
6568                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6569                                                       path->slots[0]);
6570                                 if (key.objectid == bytenr &&
6571                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6572                                     key.offset == num_bytes)
6573                                         ret = 0;
6574                         }
6575
6576                         if (ret > 0 && skinny_metadata) {
6577                                 skinny_metadata = false;
6578                                 key.objectid = bytenr;
6579                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6580                                 key.offset = num_bytes;
6581                                 btrfs_release_path(path);
6582                                 ret = btrfs_search_slot(trans, extent_root,
6583                                                         &key, path, -1, 1);
6584                         }
6585
6586                         if (ret) {
6587                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6588                                         ret, bytenr);
6589                                 if (ret > 0)
6590                                         btrfs_print_leaf(extent_root,
6591                                                          path->nodes[0]);
6592                         }
6593                         if (ret < 0) {
6594                                 btrfs_abort_transaction(trans, extent_root, ret);
6595                                 goto out;
6596                         }
6597                         extent_slot = path->slots[0];
6598                 }
6599         } else if (WARN_ON(ret == -ENOENT)) {
6600                 btrfs_print_leaf(extent_root, path->nodes[0]);
6601                 btrfs_err(info,
6602                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6603                         bytenr, parent, root_objectid, owner_objectid,
6604                         owner_offset);
6605                 btrfs_abort_transaction(trans, extent_root, ret);
6606                 goto out;
6607         } else {
6608                 btrfs_abort_transaction(trans, extent_root, ret);
6609                 goto out;
6610         }
6611
6612         leaf = path->nodes[0];
6613         item_size = btrfs_item_size_nr(leaf, extent_slot);
6614 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6615         if (item_size < sizeof(*ei)) {
6616                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6617                 ret = convert_extent_item_v0(trans, extent_root, path,
6618                                              owner_objectid, 0);
6619                 if (ret < 0) {
6620                         btrfs_abort_transaction(trans, extent_root, ret);
6621                         goto out;
6622                 }
6623
6624                 btrfs_release_path(path);
6625                 path->leave_spinning = 1;
6626
6627                 key.objectid = bytenr;
6628                 key.type = BTRFS_EXTENT_ITEM_KEY;
6629                 key.offset = num_bytes;
6630
6631                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6632                                         -1, 1);
6633                 if (ret) {
6634                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6635                                 ret, bytenr);
6636                         btrfs_print_leaf(extent_root, path->nodes[0]);
6637                 }
6638                 if (ret < 0) {
6639                         btrfs_abort_transaction(trans, extent_root, ret);
6640                         goto out;
6641                 }
6642
6643                 extent_slot = path->slots[0];
6644                 leaf = path->nodes[0];
6645                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6646         }
6647 #endif
6648         BUG_ON(item_size < sizeof(*ei));
6649         ei = btrfs_item_ptr(leaf, extent_slot,
6650                             struct btrfs_extent_item);
6651         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6652             key.type == BTRFS_EXTENT_ITEM_KEY) {
6653                 struct btrfs_tree_block_info *bi;
6654                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6655                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6656                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6657         }
6658
6659         refs = btrfs_extent_refs(leaf, ei);
6660         if (refs < refs_to_drop) {
6661                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
6662                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
6663                 ret = -EINVAL;
6664                 btrfs_abort_transaction(trans, extent_root, ret);
6665                 goto out;
6666         }
6667         refs -= refs_to_drop;
6668
6669         if (refs > 0) {
6670                 if (extent_op)
6671                         __run_delayed_extent_op(extent_op, leaf, ei);
6672                 /*
6673                  * In the case of inline back ref, reference count will
6674                  * be updated by remove_extent_backref
6675                  */
6676                 if (iref) {
6677                         BUG_ON(!found_extent);
6678                 } else {
6679                         btrfs_set_extent_refs(leaf, ei, refs);
6680                         btrfs_mark_buffer_dirty(leaf);
6681                 }
6682                 if (found_extent) {
6683                         ret = remove_extent_backref(trans, extent_root, path,
6684                                                     iref, refs_to_drop,
6685                                                     is_data, &last_ref);
6686                         if (ret) {
6687                                 btrfs_abort_transaction(trans, extent_root, ret);
6688                                 goto out;
6689                         }
6690                 }
6691                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
6692                                  root_objectid);
6693         } else {
6694                 if (found_extent) {
6695                         BUG_ON(is_data && refs_to_drop !=
6696                                extent_data_ref_count(path, iref));
6697                         if (iref) {
6698                                 BUG_ON(path->slots[0] != extent_slot);
6699                         } else {
6700                                 BUG_ON(path->slots[0] != extent_slot + 1);
6701                                 path->slots[0] = extent_slot;
6702                                 num_to_del = 2;
6703                         }
6704                 }
6705
6706                 last_ref = 1;
6707                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6708                                       num_to_del);
6709                 if (ret) {
6710                         btrfs_abort_transaction(trans, extent_root, ret);
6711                         goto out;
6712                 }
6713                 btrfs_release_path(path);
6714
6715                 if (is_data) {
6716                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
6717                         if (ret) {
6718                                 btrfs_abort_transaction(trans, extent_root, ret);
6719                                 goto out;
6720                         }
6721                 }
6722
6723                 ret = add_to_free_space_tree(trans, root->fs_info, bytenr,
6724                                              num_bytes);
6725                 if (ret) {
6726                         btrfs_abort_transaction(trans, extent_root, ret);
6727                         goto out;
6728                 }
6729
6730                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
6731                 if (ret) {
6732                         btrfs_abort_transaction(trans, extent_root, ret);
6733                         goto out;
6734                 }
6735         }
6736         btrfs_release_path(path);
6737
6738 out:
6739         btrfs_free_path(path);
6740         return ret;
6741 }
6742
6743 /*
6744  * when we free an block, it is possible (and likely) that we free the last
6745  * delayed ref for that extent as well.  This searches the delayed ref tree for
6746  * a given extent, and if there are no other delayed refs to be processed, it
6747  * removes it from the tree.
6748  */
6749 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6750                                       struct btrfs_root *root, u64 bytenr)
6751 {
6752         struct btrfs_delayed_ref_head *head;
6753         struct btrfs_delayed_ref_root *delayed_refs;
6754         int ret = 0;
6755
6756         delayed_refs = &trans->transaction->delayed_refs;
6757         spin_lock(&delayed_refs->lock);
6758         head = btrfs_find_delayed_ref_head(trans, bytenr);
6759         if (!head)
6760                 goto out_delayed_unlock;
6761
6762         spin_lock(&head->lock);
6763         if (!list_empty(&head->ref_list))
6764                 goto out;
6765
6766         if (head->extent_op) {
6767                 if (!head->must_insert_reserved)
6768                         goto out;
6769                 btrfs_free_delayed_extent_op(head->extent_op);
6770                 head->extent_op = NULL;
6771         }
6772
6773         /*
6774          * waiting for the lock here would deadlock.  If someone else has it
6775          * locked they are already in the process of dropping it anyway
6776          */
6777         if (!mutex_trylock(&head->mutex))
6778                 goto out;
6779
6780         /*
6781          * at this point we have a head with no other entries.  Go
6782          * ahead and process it.
6783          */
6784         head->node.in_tree = 0;
6785         rb_erase(&head->href_node, &delayed_refs->href_root);
6786
6787         atomic_dec(&delayed_refs->num_entries);
6788
6789         /*
6790          * we don't take a ref on the node because we're removing it from the
6791          * tree, so we just steal the ref the tree was holding.
6792          */
6793         delayed_refs->num_heads--;
6794         if (head->processing == 0)
6795                 delayed_refs->num_heads_ready--;
6796         head->processing = 0;
6797         spin_unlock(&head->lock);
6798         spin_unlock(&delayed_refs->lock);
6799
6800         BUG_ON(head->extent_op);
6801         if (head->must_insert_reserved)
6802                 ret = 1;
6803
6804         mutex_unlock(&head->mutex);
6805         btrfs_put_delayed_ref(&head->node);
6806         return ret;
6807 out:
6808         spin_unlock(&head->lock);
6809
6810 out_delayed_unlock:
6811         spin_unlock(&delayed_refs->lock);
6812         return 0;
6813 }
6814
6815 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6816                            struct btrfs_root *root,
6817                            struct extent_buffer *buf,
6818                            u64 parent, int last_ref)
6819 {
6820         int pin = 1;
6821         int ret;
6822
6823         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6824                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6825                                         buf->start, buf->len,
6826                                         parent, root->root_key.objectid,
6827                                         btrfs_header_level(buf),
6828                                         BTRFS_DROP_DELAYED_REF, NULL);
6829                 BUG_ON(ret); /* -ENOMEM */
6830         }
6831
6832         if (!last_ref)
6833                 return;
6834
6835         if (btrfs_header_generation(buf) == trans->transid) {
6836                 struct btrfs_block_group_cache *cache;
6837
6838                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6839                         ret = check_ref_cleanup(trans, root, buf->start);
6840                         if (!ret)
6841                                 goto out;
6842                 }
6843
6844                 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6845
6846                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6847                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6848                         btrfs_put_block_group(cache);
6849                         goto out;
6850                 }
6851
6852                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6853
6854                 btrfs_add_free_space(cache, buf->start, buf->len);
6855                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
6856                 btrfs_put_block_group(cache);
6857                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6858                 pin = 0;
6859         }
6860 out:
6861         if (pin)
6862                 add_pinned_bytes(root->fs_info, buf->len,
6863                                  btrfs_header_level(buf),
6864                                  root->root_key.objectid);
6865
6866         /*
6867          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6868          * anymore.
6869          */
6870         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6871 }
6872
6873 /* Can return -ENOMEM */
6874 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6875                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6876                       u64 owner, u64 offset)
6877 {
6878         int ret;
6879         struct btrfs_fs_info *fs_info = root->fs_info;
6880
6881         if (btrfs_test_is_dummy_root(root))
6882                 return 0;
6883
6884         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6885
6886         /*
6887          * tree log blocks never actually go into the extent allocation
6888          * tree, just update pinning info and exit early.
6889          */
6890         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6891                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6892                 /* unlocks the pinned mutex */
6893                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6894                 ret = 0;
6895         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6896                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6897                                         num_bytes,
6898                                         parent, root_objectid, (int)owner,
6899                                         BTRFS_DROP_DELAYED_REF, NULL);
6900         } else {
6901                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6902                                                 num_bytes,
6903                                                 parent, root_objectid, owner,
6904                                                 offset, 0,
6905                                                 BTRFS_DROP_DELAYED_REF, NULL);
6906         }
6907         return ret;
6908 }
6909
6910 /*
6911  * when we wait for progress in the block group caching, its because
6912  * our allocation attempt failed at least once.  So, we must sleep
6913  * and let some progress happen before we try again.
6914  *
6915  * This function will sleep at least once waiting for new free space to
6916  * show up, and then it will check the block group free space numbers
6917  * for our min num_bytes.  Another option is to have it go ahead
6918  * and look in the rbtree for a free extent of a given size, but this
6919  * is a good start.
6920  *
6921  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6922  * any of the information in this block group.
6923  */
6924 static noinline void
6925 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6926                                 u64 num_bytes)
6927 {
6928         struct btrfs_caching_control *caching_ctl;
6929
6930         caching_ctl = get_caching_control(cache);
6931         if (!caching_ctl)
6932                 return;
6933
6934         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6935                    (cache->free_space_ctl->free_space >= num_bytes));
6936
6937         put_caching_control(caching_ctl);
6938 }
6939
6940 static noinline int
6941 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6942 {
6943         struct btrfs_caching_control *caching_ctl;
6944         int ret = 0;
6945
6946         caching_ctl = get_caching_control(cache);
6947         if (!caching_ctl)
6948                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6949
6950         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6951         if (cache->cached == BTRFS_CACHE_ERROR)
6952                 ret = -EIO;
6953         put_caching_control(caching_ctl);
6954         return ret;
6955 }
6956
6957 int __get_raid_index(u64 flags)
6958 {
6959         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6960                 return BTRFS_RAID_RAID10;
6961         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6962                 return BTRFS_RAID_RAID1;
6963         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6964                 return BTRFS_RAID_DUP;
6965         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6966                 return BTRFS_RAID_RAID0;
6967         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6968                 return BTRFS_RAID_RAID5;
6969         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6970                 return BTRFS_RAID_RAID6;
6971
6972         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6973 }
6974
6975 int get_block_group_index(struct btrfs_block_group_cache *cache)
6976 {
6977         return __get_raid_index(cache->flags);
6978 }
6979
6980 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6981         [BTRFS_RAID_RAID10]     = "raid10",
6982         [BTRFS_RAID_RAID1]      = "raid1",
6983         [BTRFS_RAID_DUP]        = "dup",
6984         [BTRFS_RAID_RAID0]      = "raid0",
6985         [BTRFS_RAID_SINGLE]     = "single",
6986         [BTRFS_RAID_RAID5]      = "raid5",
6987         [BTRFS_RAID_RAID6]      = "raid6",
6988 };
6989
6990 static const char *get_raid_name(enum btrfs_raid_types type)
6991 {
6992         if (type >= BTRFS_NR_RAID_TYPES)
6993                 return NULL;
6994
6995         return btrfs_raid_type_names[type];
6996 }
6997
6998 enum btrfs_loop_type {
6999         LOOP_CACHING_NOWAIT = 0,
7000         LOOP_CACHING_WAIT = 1,
7001         LOOP_ALLOC_CHUNK = 2,
7002         LOOP_NO_EMPTY_SIZE = 3,
7003 };
7004
7005 static inline void
7006 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7007                        int delalloc)
7008 {
7009         if (delalloc)
7010                 down_read(&cache->data_rwsem);
7011 }
7012
7013 static inline void
7014 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7015                        int delalloc)
7016 {
7017         btrfs_get_block_group(cache);
7018         if (delalloc)
7019                 down_read(&cache->data_rwsem);
7020 }
7021
7022 static struct btrfs_block_group_cache *
7023 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7024                    struct btrfs_free_cluster *cluster,
7025                    int delalloc)
7026 {
7027         struct btrfs_block_group_cache *used_bg = NULL;
7028         bool locked = false;
7029 again:
7030         spin_lock(&cluster->refill_lock);
7031         if (locked) {
7032                 if (used_bg == cluster->block_group)
7033                         return used_bg;
7034
7035                 up_read(&used_bg->data_rwsem);
7036                 btrfs_put_block_group(used_bg);
7037         }
7038
7039         used_bg = cluster->block_group;
7040         if (!used_bg)
7041                 return NULL;
7042
7043         if (used_bg == block_group)
7044                 return used_bg;
7045
7046         btrfs_get_block_group(used_bg);
7047
7048         if (!delalloc)
7049                 return used_bg;
7050
7051         if (down_read_trylock(&used_bg->data_rwsem))
7052                 return used_bg;
7053
7054         spin_unlock(&cluster->refill_lock);
7055         down_read(&used_bg->data_rwsem);
7056         locked = true;
7057         goto again;
7058 }
7059
7060 static inline void
7061 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7062                          int delalloc)
7063 {
7064         if (delalloc)
7065                 up_read(&cache->data_rwsem);
7066         btrfs_put_block_group(cache);
7067 }
7068
7069 /*
7070  * walks the btree of allocated extents and find a hole of a given size.
7071  * The key ins is changed to record the hole:
7072  * ins->objectid == start position
7073  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7074  * ins->offset == the size of the hole.
7075  * Any available blocks before search_start are skipped.
7076  *
7077  * If there is no suitable free space, we will record the max size of
7078  * the free space extent currently.
7079  */
7080 static noinline int find_free_extent(struct btrfs_root *orig_root,
7081                                      u64 num_bytes, u64 empty_size,
7082                                      u64 hint_byte, struct btrfs_key *ins,
7083                                      u64 flags, int delalloc)
7084 {
7085         int ret = 0;
7086         struct btrfs_root *root = orig_root->fs_info->extent_root;
7087         struct btrfs_free_cluster *last_ptr = NULL;
7088         struct btrfs_block_group_cache *block_group = NULL;
7089         u64 search_start = 0;
7090         u64 max_extent_size = 0;
7091         u64 empty_cluster = 0;
7092         struct btrfs_space_info *space_info;
7093         int loop = 0;
7094         int index = __get_raid_index(flags);
7095         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
7096                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
7097         bool failed_cluster_refill = false;
7098         bool failed_alloc = false;
7099         bool use_cluster = true;
7100         bool have_caching_bg = false;
7101         bool orig_have_caching_bg = false;
7102         bool full_search = false;
7103
7104         WARN_ON(num_bytes < root->sectorsize);
7105         ins->type = BTRFS_EXTENT_ITEM_KEY;
7106         ins->objectid = 0;
7107         ins->offset = 0;
7108
7109         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
7110
7111         space_info = __find_space_info(root->fs_info, flags);
7112         if (!space_info) {
7113                 btrfs_err(root->fs_info, "No space info for %llu", flags);
7114                 return -ENOSPC;
7115         }
7116
7117         /*
7118          * If our free space is heavily fragmented we may not be able to make
7119          * big contiguous allocations, so instead of doing the expensive search
7120          * for free space, simply return ENOSPC with our max_extent_size so we
7121          * can go ahead and search for a more manageable chunk.
7122          *
7123          * If our max_extent_size is large enough for our allocation simply
7124          * disable clustering since we will likely not be able to find enough
7125          * space to create a cluster and induce latency trying.
7126          */
7127         if (unlikely(space_info->max_extent_size)) {
7128                 spin_lock(&space_info->lock);
7129                 if (space_info->max_extent_size &&
7130                     num_bytes > space_info->max_extent_size) {
7131                         ins->offset = space_info->max_extent_size;
7132                         spin_unlock(&space_info->lock);
7133                         return -ENOSPC;
7134                 } else if (space_info->max_extent_size) {
7135                         use_cluster = false;
7136                 }
7137                 spin_unlock(&space_info->lock);
7138         }
7139
7140         last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster);
7141         if (last_ptr) {
7142                 spin_lock(&last_ptr->lock);
7143                 if (last_ptr->block_group)
7144                         hint_byte = last_ptr->window_start;
7145                 if (last_ptr->fragmented) {
7146                         /*
7147                          * We still set window_start so we can keep track of the
7148                          * last place we found an allocation to try and save
7149                          * some time.
7150                          */
7151                         hint_byte = last_ptr->window_start;
7152                         use_cluster = false;
7153                 }
7154                 spin_unlock(&last_ptr->lock);
7155         }
7156
7157         search_start = max(search_start, first_logical_byte(root, 0));
7158         search_start = max(search_start, hint_byte);
7159         if (search_start == hint_byte) {
7160                 block_group = btrfs_lookup_block_group(root->fs_info,
7161                                                        search_start);
7162                 /*
7163                  * we don't want to use the block group if it doesn't match our
7164                  * allocation bits, or if its not cached.
7165                  *
7166                  * However if we are re-searching with an ideal block group
7167                  * picked out then we don't care that the block group is cached.
7168                  */
7169                 if (block_group && block_group_bits(block_group, flags) &&
7170                     block_group->cached != BTRFS_CACHE_NO) {
7171                         down_read(&space_info->groups_sem);
7172                         if (list_empty(&block_group->list) ||
7173                             block_group->ro) {
7174                                 /*
7175                                  * someone is removing this block group,
7176                                  * we can't jump into the have_block_group
7177                                  * target because our list pointers are not
7178                                  * valid
7179                                  */
7180                                 btrfs_put_block_group(block_group);
7181                                 up_read(&space_info->groups_sem);
7182                         } else {
7183                                 index = get_block_group_index(block_group);
7184                                 btrfs_lock_block_group(block_group, delalloc);
7185                                 goto have_block_group;
7186                         }
7187                 } else if (block_group) {
7188                         btrfs_put_block_group(block_group);
7189                 }
7190         }
7191 search:
7192         have_caching_bg = false;
7193         if (index == 0 || index == __get_raid_index(flags))
7194                 full_search = true;
7195         down_read(&space_info->groups_sem);
7196         list_for_each_entry(block_group, &space_info->block_groups[index],
7197                             list) {
7198                 u64 offset;
7199                 int cached;
7200
7201                 btrfs_grab_block_group(block_group, delalloc);
7202                 search_start = block_group->key.objectid;
7203
7204                 /*
7205                  * this can happen if we end up cycling through all the
7206                  * raid types, but we want to make sure we only allocate
7207                  * for the proper type.
7208                  */
7209                 if (!block_group_bits(block_group, flags)) {
7210                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7211                                 BTRFS_BLOCK_GROUP_RAID1 |
7212                                 BTRFS_BLOCK_GROUP_RAID5 |
7213                                 BTRFS_BLOCK_GROUP_RAID6 |
7214                                 BTRFS_BLOCK_GROUP_RAID10;
7215
7216                         /*
7217                          * if they asked for extra copies and this block group
7218                          * doesn't provide them, bail.  This does allow us to
7219                          * fill raid0 from raid1.
7220                          */
7221                         if ((flags & extra) && !(block_group->flags & extra))
7222                                 goto loop;
7223                 }
7224
7225 have_block_group:
7226                 cached = block_group_cache_done(block_group);
7227                 if (unlikely(!cached)) {
7228                         have_caching_bg = true;
7229                         ret = cache_block_group(block_group, 0);
7230                         BUG_ON(ret < 0);
7231                         ret = 0;
7232                 }
7233
7234                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7235                         goto loop;
7236                 if (unlikely(block_group->ro))
7237                         goto loop;
7238
7239                 /*
7240                  * Ok we want to try and use the cluster allocator, so
7241                  * lets look there
7242                  */
7243                 if (last_ptr && use_cluster) {
7244                         struct btrfs_block_group_cache *used_block_group;
7245                         unsigned long aligned_cluster;
7246                         /*
7247                          * the refill lock keeps out other
7248                          * people trying to start a new cluster
7249                          */
7250                         used_block_group = btrfs_lock_cluster(block_group,
7251                                                               last_ptr,
7252                                                               delalloc);
7253                         if (!used_block_group)
7254                                 goto refill_cluster;
7255
7256                         if (used_block_group != block_group &&
7257                             (used_block_group->ro ||
7258                              !block_group_bits(used_block_group, flags)))
7259                                 goto release_cluster;
7260
7261                         offset = btrfs_alloc_from_cluster(used_block_group,
7262                                                 last_ptr,
7263                                                 num_bytes,
7264                                                 used_block_group->key.objectid,
7265                                                 &max_extent_size);
7266                         if (offset) {
7267                                 /* we have a block, we're done */
7268                                 spin_unlock(&last_ptr->refill_lock);
7269                                 trace_btrfs_reserve_extent_cluster(root,
7270                                                 used_block_group,
7271                                                 search_start, num_bytes);
7272                                 if (used_block_group != block_group) {
7273                                         btrfs_release_block_group(block_group,
7274                                                                   delalloc);
7275                                         block_group = used_block_group;
7276                                 }
7277                                 goto checks;
7278                         }
7279
7280                         WARN_ON(last_ptr->block_group != used_block_group);
7281 release_cluster:
7282                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7283                          * set up a new clusters, so lets just skip it
7284                          * and let the allocator find whatever block
7285                          * it can find.  If we reach this point, we
7286                          * will have tried the cluster allocator
7287                          * plenty of times and not have found
7288                          * anything, so we are likely way too
7289                          * fragmented for the clustering stuff to find
7290                          * anything.
7291                          *
7292                          * However, if the cluster is taken from the
7293                          * current block group, release the cluster
7294                          * first, so that we stand a better chance of
7295                          * succeeding in the unclustered
7296                          * allocation.  */
7297                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7298                             used_block_group != block_group) {
7299                                 spin_unlock(&last_ptr->refill_lock);
7300                                 btrfs_release_block_group(used_block_group,
7301                                                           delalloc);
7302                                 goto unclustered_alloc;
7303                         }
7304
7305                         /*
7306                          * this cluster didn't work out, free it and
7307                          * start over
7308                          */
7309                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7310
7311                         if (used_block_group != block_group)
7312                                 btrfs_release_block_group(used_block_group,
7313                                                           delalloc);
7314 refill_cluster:
7315                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7316                                 spin_unlock(&last_ptr->refill_lock);
7317                                 goto unclustered_alloc;
7318                         }
7319
7320                         aligned_cluster = max_t(unsigned long,
7321                                                 empty_cluster + empty_size,
7322                                               block_group->full_stripe_len);
7323
7324                         /* allocate a cluster in this block group */
7325                         ret = btrfs_find_space_cluster(root, block_group,
7326                                                        last_ptr, search_start,
7327                                                        num_bytes,
7328                                                        aligned_cluster);
7329                         if (ret == 0) {
7330                                 /*
7331                                  * now pull our allocation out of this
7332                                  * cluster
7333                                  */
7334                                 offset = btrfs_alloc_from_cluster(block_group,
7335                                                         last_ptr,
7336                                                         num_bytes,
7337                                                         search_start,
7338                                                         &max_extent_size);
7339                                 if (offset) {
7340                                         /* we found one, proceed */
7341                                         spin_unlock(&last_ptr->refill_lock);
7342                                         trace_btrfs_reserve_extent_cluster(root,
7343                                                 block_group, search_start,
7344                                                 num_bytes);
7345                                         goto checks;
7346                                 }
7347                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7348                                    && !failed_cluster_refill) {
7349                                 spin_unlock(&last_ptr->refill_lock);
7350
7351                                 failed_cluster_refill = true;
7352                                 wait_block_group_cache_progress(block_group,
7353                                        num_bytes + empty_cluster + empty_size);
7354                                 goto have_block_group;
7355                         }
7356
7357                         /*
7358                          * at this point we either didn't find a cluster
7359                          * or we weren't able to allocate a block from our
7360                          * cluster.  Free the cluster we've been trying
7361                          * to use, and go to the next block group
7362                          */
7363                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7364                         spin_unlock(&last_ptr->refill_lock);
7365                         goto loop;
7366                 }
7367
7368 unclustered_alloc:
7369                 /*
7370                  * We are doing an unclustered alloc, set the fragmented flag so
7371                  * we don't bother trying to setup a cluster again until we get
7372                  * more space.
7373                  */
7374                 if (unlikely(last_ptr)) {
7375                         spin_lock(&last_ptr->lock);
7376                         last_ptr->fragmented = 1;
7377                         spin_unlock(&last_ptr->lock);
7378                 }
7379                 spin_lock(&block_group->free_space_ctl->tree_lock);
7380                 if (cached &&
7381                     block_group->free_space_ctl->free_space <
7382                     num_bytes + empty_cluster + empty_size) {
7383                         if (block_group->free_space_ctl->free_space >
7384                             max_extent_size)
7385                                 max_extent_size =
7386                                         block_group->free_space_ctl->free_space;
7387                         spin_unlock(&block_group->free_space_ctl->tree_lock);
7388                         goto loop;
7389                 }
7390                 spin_unlock(&block_group->free_space_ctl->tree_lock);
7391
7392                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7393                                                     num_bytes, empty_size,
7394                                                     &max_extent_size);
7395                 /*
7396                  * If we didn't find a chunk, and we haven't failed on this
7397                  * block group before, and this block group is in the middle of
7398                  * caching and we are ok with waiting, then go ahead and wait
7399                  * for progress to be made, and set failed_alloc to true.
7400                  *
7401                  * If failed_alloc is true then we've already waited on this
7402                  * block group once and should move on to the next block group.
7403                  */
7404                 if (!offset && !failed_alloc && !cached &&
7405                     loop > LOOP_CACHING_NOWAIT) {
7406                         wait_block_group_cache_progress(block_group,
7407                                                 num_bytes + empty_size);
7408                         failed_alloc = true;
7409                         goto have_block_group;
7410                 } else if (!offset) {
7411                         goto loop;
7412                 }
7413 checks:
7414                 search_start = ALIGN(offset, root->stripesize);
7415
7416                 /* move on to the next group */
7417                 if (search_start + num_bytes >
7418                     block_group->key.objectid + block_group->key.offset) {
7419                         btrfs_add_free_space(block_group, offset, num_bytes);
7420                         goto loop;
7421                 }
7422
7423                 if (offset < search_start)
7424                         btrfs_add_free_space(block_group, offset,
7425                                              search_start - offset);
7426                 BUG_ON(offset > search_start);
7427
7428                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
7429                                                   alloc_type, delalloc);
7430                 if (ret == -EAGAIN) {
7431                         btrfs_add_free_space(block_group, offset, num_bytes);
7432                         goto loop;
7433                 }
7434
7435                 /* we are all good, lets return */
7436                 ins->objectid = search_start;
7437                 ins->offset = num_bytes;
7438
7439                 trace_btrfs_reserve_extent(orig_root, block_group,
7440                                            search_start, num_bytes);
7441                 btrfs_release_block_group(block_group, delalloc);
7442                 break;
7443 loop:
7444                 failed_cluster_refill = false;
7445                 failed_alloc = false;
7446                 BUG_ON(index != get_block_group_index(block_group));
7447                 btrfs_release_block_group(block_group, delalloc);
7448         }
7449         up_read(&space_info->groups_sem);
7450
7451         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7452                 && !orig_have_caching_bg)
7453                 orig_have_caching_bg = true;
7454
7455         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7456                 goto search;
7457
7458         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7459                 goto search;
7460
7461         /*
7462          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7463          *                      caching kthreads as we move along
7464          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7465          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7466          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7467          *                      again
7468          */
7469         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7470                 index = 0;
7471                 if (loop == LOOP_CACHING_NOWAIT) {
7472                         /*
7473                          * We want to skip the LOOP_CACHING_WAIT step if we
7474                          * don't have any unached bgs and we've alrelady done a
7475                          * full search through.
7476                          */
7477                         if (orig_have_caching_bg || !full_search)
7478                                 loop = LOOP_CACHING_WAIT;
7479                         else
7480                                 loop = LOOP_ALLOC_CHUNK;
7481                 } else {
7482                         loop++;
7483                 }
7484
7485                 if (loop == LOOP_ALLOC_CHUNK) {
7486                         struct btrfs_trans_handle *trans;
7487                         int exist = 0;
7488
7489                         trans = current->journal_info;
7490                         if (trans)
7491                                 exist = 1;
7492                         else
7493                                 trans = btrfs_join_transaction(root);
7494
7495                         if (IS_ERR(trans)) {
7496                                 ret = PTR_ERR(trans);
7497                                 goto out;
7498                         }
7499
7500                         ret = do_chunk_alloc(trans, root, flags,
7501                                              CHUNK_ALLOC_FORCE);
7502
7503                         /*
7504                          * If we can't allocate a new chunk we've already looped
7505                          * through at least once, move on to the NO_EMPTY_SIZE
7506                          * case.
7507                          */
7508                         if (ret == -ENOSPC)
7509                                 loop = LOOP_NO_EMPTY_SIZE;
7510
7511                         /*
7512                          * Do not bail out on ENOSPC since we
7513                          * can do more things.
7514                          */
7515                         if (ret < 0 && ret != -ENOSPC)
7516                                 btrfs_abort_transaction(trans,
7517                                                         root, ret);
7518                         else
7519                                 ret = 0;
7520                         if (!exist)
7521                                 btrfs_end_transaction(trans, root);
7522                         if (ret)
7523                                 goto out;
7524                 }
7525
7526                 if (loop == LOOP_NO_EMPTY_SIZE) {
7527                         /*
7528                          * Don't loop again if we already have no empty_size and
7529                          * no empty_cluster.
7530                          */
7531                         if (empty_size == 0 &&
7532                             empty_cluster == 0) {
7533                                 ret = -ENOSPC;
7534                                 goto out;
7535                         }
7536                         empty_size = 0;
7537                         empty_cluster = 0;
7538                 }
7539
7540                 goto search;
7541         } else if (!ins->objectid) {
7542                 ret = -ENOSPC;
7543         } else if (ins->objectid) {
7544                 if (!use_cluster && last_ptr) {
7545                         spin_lock(&last_ptr->lock);
7546                         last_ptr->window_start = ins->objectid;
7547                         spin_unlock(&last_ptr->lock);
7548                 }
7549                 ret = 0;
7550         }
7551 out:
7552         if (ret == -ENOSPC) {
7553                 spin_lock(&space_info->lock);
7554                 space_info->max_extent_size = max_extent_size;
7555                 spin_unlock(&space_info->lock);
7556                 ins->offset = max_extent_size;
7557         }
7558         return ret;
7559 }
7560
7561 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7562                             int dump_block_groups)
7563 {
7564         struct btrfs_block_group_cache *cache;
7565         int index = 0;
7566
7567         spin_lock(&info->lock);
7568         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7569                info->flags,
7570                info->total_bytes - info->bytes_used - info->bytes_pinned -
7571                info->bytes_reserved - info->bytes_readonly,
7572                (info->full) ? "" : "not ");
7573         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7574                "reserved=%llu, may_use=%llu, readonly=%llu\n",
7575                info->total_bytes, info->bytes_used, info->bytes_pinned,
7576                info->bytes_reserved, info->bytes_may_use,
7577                info->bytes_readonly);
7578         spin_unlock(&info->lock);
7579
7580         if (!dump_block_groups)
7581                 return;
7582
7583         down_read(&info->groups_sem);
7584 again:
7585         list_for_each_entry(cache, &info->block_groups[index], list) {
7586                 spin_lock(&cache->lock);
7587                 printk(KERN_INFO "BTRFS: "
7588                            "block group %llu has %llu bytes, "
7589                            "%llu used %llu pinned %llu reserved %s\n",
7590                        cache->key.objectid, cache->key.offset,
7591                        btrfs_block_group_used(&cache->item), cache->pinned,
7592                        cache->reserved, cache->ro ? "[readonly]" : "");
7593                 btrfs_dump_free_space(cache, bytes);
7594                 spin_unlock(&cache->lock);
7595         }
7596         if (++index < BTRFS_NR_RAID_TYPES)
7597                 goto again;
7598         up_read(&info->groups_sem);
7599 }
7600
7601 int btrfs_reserve_extent(struct btrfs_root *root,
7602                          u64 num_bytes, u64 min_alloc_size,
7603                          u64 empty_size, u64 hint_byte,
7604                          struct btrfs_key *ins, int is_data, int delalloc)
7605 {
7606         bool final_tried = num_bytes == min_alloc_size;
7607         u64 flags;
7608         int ret;
7609
7610         flags = btrfs_get_alloc_profile(root, is_data);
7611 again:
7612         WARN_ON(num_bytes < root->sectorsize);
7613         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
7614                                flags, delalloc);
7615
7616         if (ret == -ENOSPC) {
7617                 if (!final_tried && ins->offset) {
7618                         num_bytes = min(num_bytes >> 1, ins->offset);
7619                         num_bytes = round_down(num_bytes, root->sectorsize);
7620                         num_bytes = max(num_bytes, min_alloc_size);
7621                         if (num_bytes == min_alloc_size)
7622                                 final_tried = true;
7623                         goto again;
7624                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7625                         struct btrfs_space_info *sinfo;
7626
7627                         sinfo = __find_space_info(root->fs_info, flags);
7628                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7629                                 flags, num_bytes);
7630                         if (sinfo)
7631                                 dump_space_info(sinfo, num_bytes, 1);
7632                 }
7633         }
7634
7635         return ret;
7636 }
7637
7638 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7639                                         u64 start, u64 len,
7640                                         int pin, int delalloc)
7641 {
7642         struct btrfs_block_group_cache *cache;
7643         int ret = 0;
7644
7645         cache = btrfs_lookup_block_group(root->fs_info, start);
7646         if (!cache) {
7647                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7648                         start);
7649                 return -ENOSPC;
7650         }
7651
7652         if (pin)
7653                 pin_down_extent(root, cache, start, len, 1);
7654         else {
7655                 if (btrfs_test_opt(root, DISCARD))
7656                         ret = btrfs_discard_extent(root, start, len, NULL);
7657                 btrfs_add_free_space(cache, start, len);
7658                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
7659         }
7660
7661         btrfs_put_block_group(cache);
7662
7663         trace_btrfs_reserved_extent_free(root, start, len);
7664
7665         return ret;
7666 }
7667
7668 int btrfs_free_reserved_extent(struct btrfs_root *root,
7669                                u64 start, u64 len, int delalloc)
7670 {
7671         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
7672 }
7673
7674 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
7675                                        u64 start, u64 len)
7676 {
7677         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
7678 }
7679
7680 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7681                                       struct btrfs_root *root,
7682                                       u64 parent, u64 root_objectid,
7683                                       u64 flags, u64 owner, u64 offset,
7684                                       struct btrfs_key *ins, int ref_mod)
7685 {
7686         int ret;
7687         struct btrfs_fs_info *fs_info = root->fs_info;
7688         struct btrfs_extent_item *extent_item;
7689         struct btrfs_extent_inline_ref *iref;
7690         struct btrfs_path *path;
7691         struct extent_buffer *leaf;
7692         int type;
7693         u32 size;
7694
7695         if (parent > 0)
7696                 type = BTRFS_SHARED_DATA_REF_KEY;
7697         else
7698                 type = BTRFS_EXTENT_DATA_REF_KEY;
7699
7700         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7701
7702         path = btrfs_alloc_path();
7703         if (!path)
7704                 return -ENOMEM;
7705
7706         path->leave_spinning = 1;
7707         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7708                                       ins, size);
7709         if (ret) {
7710                 btrfs_free_path(path);
7711                 return ret;
7712         }
7713
7714         leaf = path->nodes[0];
7715         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7716                                      struct btrfs_extent_item);
7717         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7718         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7719         btrfs_set_extent_flags(leaf, extent_item,
7720                                flags | BTRFS_EXTENT_FLAG_DATA);
7721
7722         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7723         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7724         if (parent > 0) {
7725                 struct btrfs_shared_data_ref *ref;
7726                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7727                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7728                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7729         } else {
7730                 struct btrfs_extent_data_ref *ref;
7731                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7732                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7733                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7734                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7735                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7736         }
7737
7738         btrfs_mark_buffer_dirty(path->nodes[0]);
7739         btrfs_free_path(path);
7740
7741         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
7742                                           ins->offset);
7743         if (ret)
7744                 return ret;
7745
7746         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
7747         if (ret) { /* -ENOENT, logic error */
7748                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7749                         ins->objectid, ins->offset);
7750                 BUG();
7751         }
7752         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
7753         return ret;
7754 }
7755
7756 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7757                                      struct btrfs_root *root,
7758                                      u64 parent, u64 root_objectid,
7759                                      u64 flags, struct btrfs_disk_key *key,
7760                                      int level, struct btrfs_key *ins)
7761 {
7762         int ret;
7763         struct btrfs_fs_info *fs_info = root->fs_info;
7764         struct btrfs_extent_item *extent_item;
7765         struct btrfs_tree_block_info *block_info;
7766         struct btrfs_extent_inline_ref *iref;
7767         struct btrfs_path *path;
7768         struct extent_buffer *leaf;
7769         u32 size = sizeof(*extent_item) + sizeof(*iref);
7770         u64 num_bytes = ins->offset;
7771         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7772                                                  SKINNY_METADATA);
7773
7774         if (!skinny_metadata)
7775                 size += sizeof(*block_info);
7776
7777         path = btrfs_alloc_path();
7778         if (!path) {
7779                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7780                                                    root->nodesize);
7781                 return -ENOMEM;
7782         }
7783
7784         path->leave_spinning = 1;
7785         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7786                                       ins, size);
7787         if (ret) {
7788                 btrfs_free_path(path);
7789                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7790                                                    root->nodesize);
7791                 return ret;
7792         }
7793
7794         leaf = path->nodes[0];
7795         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7796                                      struct btrfs_extent_item);
7797         btrfs_set_extent_refs(leaf, extent_item, 1);
7798         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7799         btrfs_set_extent_flags(leaf, extent_item,
7800                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
7801
7802         if (skinny_metadata) {
7803                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7804                 num_bytes = root->nodesize;
7805         } else {
7806                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
7807                 btrfs_set_tree_block_key(leaf, block_info, key);
7808                 btrfs_set_tree_block_level(leaf, block_info, level);
7809                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
7810         }
7811
7812         if (parent > 0) {
7813                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
7814                 btrfs_set_extent_inline_ref_type(leaf, iref,
7815                                                  BTRFS_SHARED_BLOCK_REF_KEY);
7816                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7817         } else {
7818                 btrfs_set_extent_inline_ref_type(leaf, iref,
7819                                                  BTRFS_TREE_BLOCK_REF_KEY);
7820                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
7821         }
7822
7823         btrfs_mark_buffer_dirty(leaf);
7824         btrfs_free_path(path);
7825
7826         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
7827                                           num_bytes);
7828         if (ret)
7829                 return ret;
7830
7831         ret = update_block_group(trans, root, ins->objectid, root->nodesize,
7832                                  1);
7833         if (ret) { /* -ENOENT, logic error */
7834                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7835                         ins->objectid, ins->offset);
7836                 BUG();
7837         }
7838
7839         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
7840         return ret;
7841 }
7842
7843 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7844                                      struct btrfs_root *root,
7845                                      u64 root_objectid, u64 owner,
7846                                      u64 offset, u64 ram_bytes,
7847                                      struct btrfs_key *ins)
7848 {
7849         int ret;
7850
7851         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
7852
7853         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
7854                                          ins->offset, 0,
7855                                          root_objectid, owner, offset,
7856                                          ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
7857                                          NULL);
7858         return ret;
7859 }
7860
7861 /*
7862  * this is used by the tree logging recovery code.  It records that
7863  * an extent has been allocated and makes sure to clear the free
7864  * space cache bits as well
7865  */
7866 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
7867                                    struct btrfs_root *root,
7868                                    u64 root_objectid, u64 owner, u64 offset,
7869                                    struct btrfs_key *ins)
7870 {
7871         int ret;
7872         struct btrfs_block_group_cache *block_group;
7873
7874         /*
7875          * Mixed block groups will exclude before processing the log so we only
7876          * need to do the exlude dance if this fs isn't mixed.
7877          */
7878         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
7879                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
7880                 if (ret)
7881                         return ret;
7882         }
7883
7884         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
7885         if (!block_group)
7886                 return -EINVAL;
7887
7888         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
7889                                           RESERVE_ALLOC_NO_ACCOUNT, 0);
7890         BUG_ON(ret); /* logic error */
7891         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
7892                                          0, owner, offset, ins, 1);
7893         btrfs_put_block_group(block_group);
7894         return ret;
7895 }
7896
7897 static struct extent_buffer *
7898 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7899                       u64 bytenr, int level)
7900 {
7901         struct extent_buffer *buf;
7902
7903         buf = btrfs_find_create_tree_block(root, bytenr);
7904         if (!buf)
7905                 return ERR_PTR(-ENOMEM);
7906         btrfs_set_header_generation(buf, trans->transid);
7907         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
7908         btrfs_tree_lock(buf);
7909         clean_tree_block(trans, root->fs_info, buf);
7910         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
7911
7912         btrfs_set_lock_blocking(buf);
7913         set_extent_buffer_uptodate(buf);
7914
7915         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
7916                 buf->log_index = root->log_transid % 2;
7917                 /*
7918                  * we allow two log transactions at a time, use different
7919                  * EXENT bit to differentiate dirty pages.
7920                  */
7921                 if (buf->log_index == 0)
7922                         set_extent_dirty(&root->dirty_log_pages, buf->start,
7923                                         buf->start + buf->len - 1, GFP_NOFS);
7924                 else
7925                         set_extent_new(&root->dirty_log_pages, buf->start,
7926                                         buf->start + buf->len - 1, GFP_NOFS);
7927         } else {
7928                 buf->log_index = -1;
7929                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
7930                          buf->start + buf->len - 1, GFP_NOFS);
7931         }
7932         trans->blocks_used++;
7933         /* this returns a buffer locked for blocking */
7934         return buf;
7935 }
7936
7937 static struct btrfs_block_rsv *
7938 use_block_rsv(struct btrfs_trans_handle *trans,
7939               struct btrfs_root *root, u32 blocksize)
7940 {
7941         struct btrfs_block_rsv *block_rsv;
7942         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
7943         int ret;
7944         bool global_updated = false;
7945
7946         block_rsv = get_block_rsv(trans, root);
7947
7948         if (unlikely(block_rsv->size == 0))
7949                 goto try_reserve;
7950 again:
7951         ret = block_rsv_use_bytes(block_rsv, blocksize);
7952         if (!ret)
7953                 return block_rsv;
7954
7955         if (block_rsv->failfast)
7956                 return ERR_PTR(ret);
7957
7958         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
7959                 global_updated = true;
7960                 update_global_block_rsv(root->fs_info);
7961                 goto again;
7962         }
7963
7964         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7965                 static DEFINE_RATELIMIT_STATE(_rs,
7966                                 DEFAULT_RATELIMIT_INTERVAL * 10,
7967                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
7968                 if (__ratelimit(&_rs))
7969                         WARN(1, KERN_DEBUG
7970                                 "BTRFS: block rsv returned %d\n", ret);
7971         }
7972 try_reserve:
7973         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
7974                                      BTRFS_RESERVE_NO_FLUSH);
7975         if (!ret)
7976                 return block_rsv;
7977         /*
7978          * If we couldn't reserve metadata bytes try and use some from
7979          * the global reserve if its space type is the same as the global
7980          * reservation.
7981          */
7982         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
7983             block_rsv->space_info == global_rsv->space_info) {
7984                 ret = block_rsv_use_bytes(global_rsv, blocksize);
7985                 if (!ret)
7986                         return global_rsv;
7987         }
7988         return ERR_PTR(ret);
7989 }
7990
7991 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
7992                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
7993 {
7994         block_rsv_add_bytes(block_rsv, blocksize, 0);
7995         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
7996 }
7997
7998 /*
7999  * finds a free extent and does all the dirty work required for allocation
8000  * returns the tree buffer or an ERR_PTR on error.
8001  */
8002 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8003                                         struct btrfs_root *root,
8004                                         u64 parent, u64 root_objectid,
8005                                         struct btrfs_disk_key *key, int level,
8006                                         u64 hint, u64 empty_size)
8007 {
8008         struct btrfs_key ins;
8009         struct btrfs_block_rsv *block_rsv;
8010         struct extent_buffer *buf;
8011         struct btrfs_delayed_extent_op *extent_op;
8012         u64 flags = 0;
8013         int ret;
8014         u32 blocksize = root->nodesize;
8015         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8016                                                  SKINNY_METADATA);
8017
8018         if (btrfs_test_is_dummy_root(root)) {
8019                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8020                                             level);
8021                 if (!IS_ERR(buf))
8022                         root->alloc_bytenr += blocksize;
8023                 return buf;
8024         }
8025
8026         block_rsv = use_block_rsv(trans, root, blocksize);
8027         if (IS_ERR(block_rsv))
8028                 return ERR_CAST(block_rsv);
8029
8030         ret = btrfs_reserve_extent(root, blocksize, blocksize,
8031                                    empty_size, hint, &ins, 0, 0);
8032         if (ret)
8033                 goto out_unuse;
8034
8035         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8036         if (IS_ERR(buf)) {
8037                 ret = PTR_ERR(buf);
8038                 goto out_free_reserved;
8039         }
8040
8041         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8042                 if (parent == 0)
8043                         parent = ins.objectid;
8044                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8045         } else
8046                 BUG_ON(parent > 0);
8047
8048         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8049                 extent_op = btrfs_alloc_delayed_extent_op();
8050                 if (!extent_op) {
8051                         ret = -ENOMEM;
8052                         goto out_free_buf;
8053                 }
8054                 if (key)
8055                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8056                 else
8057                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8058                 extent_op->flags_to_set = flags;
8059                 extent_op->update_key = skinny_metadata ? false : true;
8060                 extent_op->update_flags = true;
8061                 extent_op->is_data = false;
8062                 extent_op->level = level;
8063
8064                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
8065                                                  ins.objectid, ins.offset,
8066                                                  parent, root_objectid, level,
8067                                                  BTRFS_ADD_DELAYED_EXTENT,
8068                                                  extent_op);
8069                 if (ret)
8070                         goto out_free_delayed;
8071         }
8072         return buf;
8073
8074 out_free_delayed:
8075         btrfs_free_delayed_extent_op(extent_op);
8076 out_free_buf:
8077         free_extent_buffer(buf);
8078 out_free_reserved:
8079         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
8080 out_unuse:
8081         unuse_block_rsv(root->fs_info, block_rsv, blocksize);
8082         return ERR_PTR(ret);
8083 }
8084
8085 struct walk_control {
8086         u64 refs[BTRFS_MAX_LEVEL];
8087         u64 flags[BTRFS_MAX_LEVEL];
8088         struct btrfs_key update_progress;
8089         int stage;
8090         int level;
8091         int shared_level;
8092         int update_ref;
8093         int keep_locks;
8094         int reada_slot;
8095         int reada_count;
8096         int for_reloc;
8097 };
8098
8099 #define DROP_REFERENCE  1
8100 #define UPDATE_BACKREF  2
8101
8102 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8103                                      struct btrfs_root *root,
8104                                      struct walk_control *wc,
8105                                      struct btrfs_path *path)
8106 {
8107         u64 bytenr;
8108         u64 generation;
8109         u64 refs;
8110         u64 flags;
8111         u32 nritems;
8112         u32 blocksize;
8113         struct btrfs_key key;
8114         struct extent_buffer *eb;
8115         int ret;
8116         int slot;
8117         int nread = 0;
8118
8119         if (path->slots[wc->level] < wc->reada_slot) {
8120                 wc->reada_count = wc->reada_count * 2 / 3;
8121                 wc->reada_count = max(wc->reada_count, 2);
8122         } else {
8123                 wc->reada_count = wc->reada_count * 3 / 2;
8124                 wc->reada_count = min_t(int, wc->reada_count,
8125                                         BTRFS_NODEPTRS_PER_BLOCK(root));
8126         }
8127
8128         eb = path->nodes[wc->level];
8129         nritems = btrfs_header_nritems(eb);
8130         blocksize = root->nodesize;
8131
8132         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8133                 if (nread >= wc->reada_count)
8134                         break;
8135
8136                 cond_resched();
8137                 bytenr = btrfs_node_blockptr(eb, slot);
8138                 generation = btrfs_node_ptr_generation(eb, slot);
8139
8140                 if (slot == path->slots[wc->level])
8141                         goto reada;
8142
8143                 if (wc->stage == UPDATE_BACKREF &&
8144                     generation <= root->root_key.offset)
8145                         continue;
8146
8147                 /* We don't lock the tree block, it's OK to be racy here */
8148                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
8149                                                wc->level - 1, 1, &refs,
8150                                                &flags);
8151                 /* We don't care about errors in readahead. */
8152                 if (ret < 0)
8153                         continue;
8154                 BUG_ON(refs == 0);
8155
8156                 if (wc->stage == DROP_REFERENCE) {
8157                         if (refs == 1)
8158                                 goto reada;
8159
8160                         if (wc->level == 1 &&
8161                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8162                                 continue;
8163                         if (!wc->update_ref ||
8164                             generation <= root->root_key.offset)
8165                                 continue;
8166                         btrfs_node_key_to_cpu(eb, &key, slot);
8167                         ret = btrfs_comp_cpu_keys(&key,
8168                                                   &wc->update_progress);
8169                         if (ret < 0)
8170                                 continue;
8171                 } else {
8172                         if (wc->level == 1 &&
8173                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8174                                 continue;
8175                 }
8176 reada:
8177                 readahead_tree_block(root, bytenr);
8178                 nread++;
8179         }
8180         wc->reada_slot = slot;
8181 }
8182
8183 /*
8184  * These may not be seen by the usual inc/dec ref code so we have to
8185  * add them here.
8186  */
8187 static int record_one_subtree_extent(struct btrfs_trans_handle *trans,
8188                                      struct btrfs_root *root, u64 bytenr,
8189                                      u64 num_bytes)
8190 {
8191         struct btrfs_qgroup_extent_record *qrecord;
8192         struct btrfs_delayed_ref_root *delayed_refs;
8193
8194         qrecord = kmalloc(sizeof(*qrecord), GFP_NOFS);
8195         if (!qrecord)
8196                 return -ENOMEM;
8197
8198         qrecord->bytenr = bytenr;
8199         qrecord->num_bytes = num_bytes;
8200         qrecord->old_roots = NULL;
8201
8202         delayed_refs = &trans->transaction->delayed_refs;
8203         spin_lock(&delayed_refs->lock);
8204         if (btrfs_qgroup_insert_dirty_extent(delayed_refs, qrecord))
8205                 kfree(qrecord);
8206         spin_unlock(&delayed_refs->lock);
8207
8208         return 0;
8209 }
8210
8211 static int account_leaf_items(struct btrfs_trans_handle *trans,
8212                               struct btrfs_root *root,
8213                               struct extent_buffer *eb)
8214 {
8215         int nr = btrfs_header_nritems(eb);
8216         int i, extent_type, ret;
8217         struct btrfs_key key;
8218         struct btrfs_file_extent_item *fi;
8219         u64 bytenr, num_bytes;
8220
8221         /* We can be called directly from walk_up_proc() */
8222         if (!root->fs_info->quota_enabled)
8223                 return 0;
8224
8225         for (i = 0; i < nr; i++) {
8226                 btrfs_item_key_to_cpu(eb, &key, i);
8227
8228                 if (key.type != BTRFS_EXTENT_DATA_KEY)
8229                         continue;
8230
8231                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
8232                 /* filter out non qgroup-accountable extents  */
8233                 extent_type = btrfs_file_extent_type(eb, fi);
8234
8235                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
8236                         continue;
8237
8238                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
8239                 if (!bytenr)
8240                         continue;
8241
8242                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
8243
8244                 ret = record_one_subtree_extent(trans, root, bytenr, num_bytes);
8245                 if (ret)
8246                         return ret;
8247         }
8248         return 0;
8249 }
8250
8251 /*
8252  * Walk up the tree from the bottom, freeing leaves and any interior
8253  * nodes which have had all slots visited. If a node (leaf or
8254  * interior) is freed, the node above it will have it's slot
8255  * incremented. The root node will never be freed.
8256  *
8257  * At the end of this function, we should have a path which has all
8258  * slots incremented to the next position for a search. If we need to
8259  * read a new node it will be NULL and the node above it will have the
8260  * correct slot selected for a later read.
8261  *
8262  * If we increment the root nodes slot counter past the number of
8263  * elements, 1 is returned to signal completion of the search.
8264  */
8265 static int adjust_slots_upwards(struct btrfs_root *root,
8266                                 struct btrfs_path *path, int root_level)
8267 {
8268         int level = 0;
8269         int nr, slot;
8270         struct extent_buffer *eb;
8271
8272         if (root_level == 0)
8273                 return 1;
8274
8275         while (level <= root_level) {
8276                 eb = path->nodes[level];
8277                 nr = btrfs_header_nritems(eb);
8278                 path->slots[level]++;
8279                 slot = path->slots[level];
8280                 if (slot >= nr || level == 0) {
8281                         /*
8282                          * Don't free the root -  we will detect this
8283                          * condition after our loop and return a
8284                          * positive value for caller to stop walking the tree.
8285                          */
8286                         if (level != root_level) {
8287                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8288                                 path->locks[level] = 0;
8289
8290                                 free_extent_buffer(eb);
8291                                 path->nodes[level] = NULL;
8292                                 path->slots[level] = 0;
8293                         }
8294                 } else {
8295                         /*
8296                          * We have a valid slot to walk back down
8297                          * from. Stop here so caller can process these
8298                          * new nodes.
8299                          */
8300                         break;
8301                 }
8302
8303                 level++;
8304         }
8305
8306         eb = path->nodes[root_level];
8307         if (path->slots[root_level] >= btrfs_header_nritems(eb))
8308                 return 1;
8309
8310         return 0;
8311 }
8312
8313 /*
8314  * root_eb is the subtree root and is locked before this function is called.
8315  */
8316 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8317                                   struct btrfs_root *root,
8318                                   struct extent_buffer *root_eb,
8319                                   u64 root_gen,
8320                                   int root_level)
8321 {
8322         int ret = 0;
8323         int level;
8324         struct extent_buffer *eb = root_eb;
8325         struct btrfs_path *path = NULL;
8326
8327         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8328         BUG_ON(root_eb == NULL);
8329
8330         if (!root->fs_info->quota_enabled)
8331                 return 0;
8332
8333         if (!extent_buffer_uptodate(root_eb)) {
8334                 ret = btrfs_read_buffer(root_eb, root_gen);
8335                 if (ret)
8336                         goto out;
8337         }
8338
8339         if (root_level == 0) {
8340                 ret = account_leaf_items(trans, root, root_eb);
8341                 goto out;
8342         }
8343
8344         path = btrfs_alloc_path();
8345         if (!path)
8346                 return -ENOMEM;
8347
8348         /*
8349          * Walk down the tree.  Missing extent blocks are filled in as
8350          * we go. Metadata is accounted every time we read a new
8351          * extent block.
8352          *
8353          * When we reach a leaf, we account for file extent items in it,
8354          * walk back up the tree (adjusting slot pointers as we go)
8355          * and restart the search process.
8356          */
8357         extent_buffer_get(root_eb); /* For path */
8358         path->nodes[root_level] = root_eb;
8359         path->slots[root_level] = 0;
8360         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8361 walk_down:
8362         level = root_level;
8363         while (level >= 0) {
8364                 if (path->nodes[level] == NULL) {
8365                         int parent_slot;
8366                         u64 child_gen;
8367                         u64 child_bytenr;
8368
8369                         /* We need to get child blockptr/gen from
8370                          * parent before we can read it. */
8371                         eb = path->nodes[level + 1];
8372                         parent_slot = path->slots[level + 1];
8373                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8374                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8375
8376                         eb = read_tree_block(root, child_bytenr, child_gen);
8377                         if (IS_ERR(eb)) {
8378                                 ret = PTR_ERR(eb);
8379                                 goto out;
8380                         } else if (!extent_buffer_uptodate(eb)) {
8381                                 free_extent_buffer(eb);
8382                                 ret = -EIO;
8383                                 goto out;
8384                         }
8385
8386                         path->nodes[level] = eb;
8387                         path->slots[level] = 0;
8388
8389                         btrfs_tree_read_lock(eb);
8390                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8391                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8392
8393                         ret = record_one_subtree_extent(trans, root, child_bytenr,
8394                                                         root->nodesize);
8395                         if (ret)
8396                                 goto out;
8397                 }
8398
8399                 if (level == 0) {
8400                         ret = account_leaf_items(trans, root, path->nodes[level]);
8401                         if (ret)
8402                                 goto out;
8403
8404                         /* Nonzero return here means we completed our search */
8405                         ret = adjust_slots_upwards(root, path, root_level);
8406                         if (ret)
8407                                 break;
8408
8409                         /* Restart search with new slots */
8410                         goto walk_down;
8411                 }
8412
8413                 level--;
8414         }
8415
8416         ret = 0;
8417 out:
8418         btrfs_free_path(path);
8419
8420         return ret;
8421 }
8422
8423 /*
8424  * helper to process tree block while walking down the tree.
8425  *
8426  * when wc->stage == UPDATE_BACKREF, this function updates
8427  * back refs for pointers in the block.
8428  *
8429  * NOTE: return value 1 means we should stop walking down.
8430  */
8431 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8432                                    struct btrfs_root *root,
8433                                    struct btrfs_path *path,
8434                                    struct walk_control *wc, int lookup_info)
8435 {
8436         int level = wc->level;
8437         struct extent_buffer *eb = path->nodes[level];
8438         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8439         int ret;
8440
8441         if (wc->stage == UPDATE_BACKREF &&
8442             btrfs_header_owner(eb) != root->root_key.objectid)
8443                 return 1;
8444
8445         /*
8446          * when reference count of tree block is 1, it won't increase
8447          * again. once full backref flag is set, we never clear it.
8448          */
8449         if (lookup_info &&
8450             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8451              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8452                 BUG_ON(!path->locks[level]);
8453                 ret = btrfs_lookup_extent_info(trans, root,
8454                                                eb->start, level, 1,
8455                                                &wc->refs[level],
8456                                                &wc->flags[level]);
8457                 BUG_ON(ret == -ENOMEM);
8458                 if (ret)
8459                         return ret;
8460                 BUG_ON(wc->refs[level] == 0);
8461         }
8462
8463         if (wc->stage == DROP_REFERENCE) {
8464                 if (wc->refs[level] > 1)
8465                         return 1;
8466
8467                 if (path->locks[level] && !wc->keep_locks) {
8468                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8469                         path->locks[level] = 0;
8470                 }
8471                 return 0;
8472         }
8473
8474         /* wc->stage == UPDATE_BACKREF */
8475         if (!(wc->flags[level] & flag)) {
8476                 BUG_ON(!path->locks[level]);
8477                 ret = btrfs_inc_ref(trans, root, eb, 1);
8478                 BUG_ON(ret); /* -ENOMEM */
8479                 ret = btrfs_dec_ref(trans, root, eb, 0);
8480                 BUG_ON(ret); /* -ENOMEM */
8481                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8482                                                   eb->len, flag,
8483                                                   btrfs_header_level(eb), 0);
8484                 BUG_ON(ret); /* -ENOMEM */
8485                 wc->flags[level] |= flag;
8486         }
8487
8488         /*
8489          * the block is shared by multiple trees, so it's not good to
8490          * keep the tree lock
8491          */
8492         if (path->locks[level] && level > 0) {
8493                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8494                 path->locks[level] = 0;
8495         }
8496         return 0;
8497 }
8498
8499 /*
8500  * helper to process tree block pointer.
8501  *
8502  * when wc->stage == DROP_REFERENCE, this function checks
8503  * reference count of the block pointed to. if the block
8504  * is shared and we need update back refs for the subtree
8505  * rooted at the block, this function changes wc->stage to
8506  * UPDATE_BACKREF. if the block is shared and there is no
8507  * need to update back, this function drops the reference
8508  * to the block.
8509  *
8510  * NOTE: return value 1 means we should stop walking down.
8511  */
8512 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8513                                  struct btrfs_root *root,
8514                                  struct btrfs_path *path,
8515                                  struct walk_control *wc, int *lookup_info)
8516 {
8517         u64 bytenr;
8518         u64 generation;
8519         u64 parent;
8520         u32 blocksize;
8521         struct btrfs_key key;
8522         struct extent_buffer *next;
8523         int level = wc->level;
8524         int reada = 0;
8525         int ret = 0;
8526         bool need_account = false;
8527
8528         generation = btrfs_node_ptr_generation(path->nodes[level],
8529                                                path->slots[level]);
8530         /*
8531          * if the lower level block was created before the snapshot
8532          * was created, we know there is no need to update back refs
8533          * for the subtree
8534          */
8535         if (wc->stage == UPDATE_BACKREF &&
8536             generation <= root->root_key.offset) {
8537                 *lookup_info = 1;
8538                 return 1;
8539         }
8540
8541         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8542         blocksize = root->nodesize;
8543
8544         next = btrfs_find_tree_block(root->fs_info, bytenr);
8545         if (!next) {
8546                 next = btrfs_find_create_tree_block(root, bytenr);
8547                 if (!next)
8548                         return -ENOMEM;
8549                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8550                                                level - 1);
8551                 reada = 1;
8552         }
8553         btrfs_tree_lock(next);
8554         btrfs_set_lock_blocking(next);
8555
8556         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8557                                        &wc->refs[level - 1],
8558                                        &wc->flags[level - 1]);
8559         if (ret < 0) {
8560                 btrfs_tree_unlock(next);
8561                 return ret;
8562         }
8563
8564         if (unlikely(wc->refs[level - 1] == 0)) {
8565                 btrfs_err(root->fs_info, "Missing references.");
8566                 BUG();
8567         }
8568         *lookup_info = 0;
8569
8570         if (wc->stage == DROP_REFERENCE) {
8571                 if (wc->refs[level - 1] > 1) {
8572                         need_account = true;
8573                         if (level == 1 &&
8574                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8575                                 goto skip;
8576
8577                         if (!wc->update_ref ||
8578                             generation <= root->root_key.offset)
8579                                 goto skip;
8580
8581                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8582                                               path->slots[level]);
8583                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8584                         if (ret < 0)
8585                                 goto skip;
8586
8587                         wc->stage = UPDATE_BACKREF;
8588                         wc->shared_level = level - 1;
8589                 }
8590         } else {
8591                 if (level == 1 &&
8592                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8593                         goto skip;
8594         }
8595
8596         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8597                 btrfs_tree_unlock(next);
8598                 free_extent_buffer(next);
8599                 next = NULL;
8600                 *lookup_info = 1;
8601         }
8602
8603         if (!next) {
8604                 if (reada && level == 1)
8605                         reada_walk_down(trans, root, wc, path);
8606                 next = read_tree_block(root, bytenr, generation);
8607                 if (IS_ERR(next)) {
8608                         return PTR_ERR(next);
8609                 } else if (!extent_buffer_uptodate(next)) {
8610                         free_extent_buffer(next);
8611                         return -EIO;
8612                 }
8613                 btrfs_tree_lock(next);
8614                 btrfs_set_lock_blocking(next);
8615         }
8616
8617         level--;
8618         BUG_ON(level != btrfs_header_level(next));
8619         path->nodes[level] = next;
8620         path->slots[level] = 0;
8621         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8622         wc->level = level;
8623         if (wc->level == 1)
8624                 wc->reada_slot = 0;
8625         return 0;
8626 skip:
8627         wc->refs[level - 1] = 0;
8628         wc->flags[level - 1] = 0;
8629         if (wc->stage == DROP_REFERENCE) {
8630                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8631                         parent = path->nodes[level]->start;
8632                 } else {
8633                         BUG_ON(root->root_key.objectid !=
8634                                btrfs_header_owner(path->nodes[level]));
8635                         parent = 0;
8636                 }
8637
8638                 if (need_account) {
8639                         ret = account_shared_subtree(trans, root, next,
8640                                                      generation, level - 1);
8641                         if (ret) {
8642                                 btrfs_err_rl(root->fs_info,
8643                                         "Error "
8644                                         "%d accounting shared subtree. Quota "
8645                                         "is out of sync, rescan required.",
8646                                         ret);
8647                         }
8648                 }
8649                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8650                                 root->root_key.objectid, level - 1, 0);
8651                 BUG_ON(ret); /* -ENOMEM */
8652         }
8653         btrfs_tree_unlock(next);
8654         free_extent_buffer(next);
8655         *lookup_info = 1;
8656         return 1;
8657 }
8658
8659 /*
8660  * helper to process tree block while walking up the tree.
8661  *
8662  * when wc->stage == DROP_REFERENCE, this function drops
8663  * reference count on the block.
8664  *
8665  * when wc->stage == UPDATE_BACKREF, this function changes
8666  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8667  * to UPDATE_BACKREF previously while processing the block.
8668  *
8669  * NOTE: return value 1 means we should stop walking up.
8670  */
8671 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8672                                  struct btrfs_root *root,
8673                                  struct btrfs_path *path,
8674                                  struct walk_control *wc)
8675 {
8676         int ret;
8677         int level = wc->level;
8678         struct extent_buffer *eb = path->nodes[level];
8679         u64 parent = 0;
8680
8681         if (wc->stage == UPDATE_BACKREF) {
8682                 BUG_ON(wc->shared_level < level);
8683                 if (level < wc->shared_level)
8684                         goto out;
8685
8686                 ret = find_next_key(path, level + 1, &wc->update_progress);
8687                 if (ret > 0)
8688                         wc->update_ref = 0;
8689
8690                 wc->stage = DROP_REFERENCE;
8691                 wc->shared_level = -1;
8692                 path->slots[level] = 0;
8693
8694                 /*
8695                  * check reference count again if the block isn't locked.
8696                  * we should start walking down the tree again if reference
8697                  * count is one.
8698                  */
8699                 if (!path->locks[level]) {
8700                         BUG_ON(level == 0);
8701                         btrfs_tree_lock(eb);
8702                         btrfs_set_lock_blocking(eb);
8703                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8704
8705                         ret = btrfs_lookup_extent_info(trans, root,
8706                                                        eb->start, level, 1,
8707                                                        &wc->refs[level],
8708                                                        &wc->flags[level]);
8709                         if (ret < 0) {
8710                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8711                                 path->locks[level] = 0;
8712                                 return ret;
8713                         }
8714                         BUG_ON(wc->refs[level] == 0);
8715                         if (wc->refs[level] == 1) {
8716                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8717                                 path->locks[level] = 0;
8718                                 return 1;
8719                         }
8720                 }
8721         }
8722
8723         /* wc->stage == DROP_REFERENCE */
8724         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8725
8726         if (wc->refs[level] == 1) {
8727                 if (level == 0) {
8728                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8729                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8730                         else
8731                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8732                         BUG_ON(ret); /* -ENOMEM */
8733                         ret = account_leaf_items(trans, root, eb);
8734                         if (ret) {
8735                                 btrfs_err_rl(root->fs_info,
8736                                         "error "
8737                                         "%d accounting leaf items. Quota "
8738                                         "is out of sync, rescan required.",
8739                                         ret);
8740                         }
8741                 }
8742                 /* make block locked assertion in clean_tree_block happy */
8743                 if (!path->locks[level] &&
8744                     btrfs_header_generation(eb) == trans->transid) {
8745                         btrfs_tree_lock(eb);
8746                         btrfs_set_lock_blocking(eb);
8747                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8748                 }
8749                 clean_tree_block(trans, root->fs_info, eb);
8750         }
8751
8752         if (eb == root->node) {
8753                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8754                         parent = eb->start;
8755                 else
8756                         BUG_ON(root->root_key.objectid !=
8757                                btrfs_header_owner(eb));
8758         } else {
8759                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8760                         parent = path->nodes[level + 1]->start;
8761                 else
8762                         BUG_ON(root->root_key.objectid !=
8763                                btrfs_header_owner(path->nodes[level + 1]));
8764         }
8765
8766         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8767 out:
8768         wc->refs[level] = 0;
8769         wc->flags[level] = 0;
8770         return 0;
8771 }
8772
8773 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8774                                    struct btrfs_root *root,
8775                                    struct btrfs_path *path,
8776                                    struct walk_control *wc)
8777 {
8778         int level = wc->level;
8779         int lookup_info = 1;
8780         int ret;
8781
8782         while (level >= 0) {
8783                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8784                 if (ret > 0)
8785                         break;
8786
8787                 if (level == 0)
8788                         break;
8789
8790                 if (path->slots[level] >=
8791                     btrfs_header_nritems(path->nodes[level]))
8792                         break;
8793
8794                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8795                 if (ret > 0) {
8796                         path->slots[level]++;
8797                         continue;
8798                 } else if (ret < 0)
8799                         return ret;
8800                 level = wc->level;
8801         }
8802         return 0;
8803 }
8804
8805 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8806                                  struct btrfs_root *root,
8807                                  struct btrfs_path *path,
8808                                  struct walk_control *wc, int max_level)
8809 {
8810         int level = wc->level;
8811         int ret;
8812
8813         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8814         while (level < max_level && path->nodes[level]) {
8815                 wc->level = level;
8816                 if (path->slots[level] + 1 <
8817                     btrfs_header_nritems(path->nodes[level])) {
8818                         path->slots[level]++;
8819                         return 0;
8820                 } else {
8821                         ret = walk_up_proc(trans, root, path, wc);
8822                         if (ret > 0)
8823                                 return 0;
8824
8825                         if (path->locks[level]) {
8826                                 btrfs_tree_unlock_rw(path->nodes[level],
8827                                                      path->locks[level]);
8828                                 path->locks[level] = 0;
8829                         }
8830                         free_extent_buffer(path->nodes[level]);
8831                         path->nodes[level] = NULL;
8832                         level++;
8833                 }
8834         }
8835         return 1;
8836 }
8837
8838 /*
8839  * drop a subvolume tree.
8840  *
8841  * this function traverses the tree freeing any blocks that only
8842  * referenced by the tree.
8843  *
8844  * when a shared tree block is found. this function decreases its
8845  * reference count by one. if update_ref is true, this function
8846  * also make sure backrefs for the shared block and all lower level
8847  * blocks are properly updated.
8848  *
8849  * If called with for_reloc == 0, may exit early with -EAGAIN
8850  */
8851 int btrfs_drop_snapshot(struct btrfs_root *root,
8852                          struct btrfs_block_rsv *block_rsv, int update_ref,
8853                          int for_reloc)
8854 {
8855         struct btrfs_path *path;
8856         struct btrfs_trans_handle *trans;
8857         struct btrfs_root *tree_root = root->fs_info->tree_root;
8858         struct btrfs_root_item *root_item = &root->root_item;
8859         struct walk_control *wc;
8860         struct btrfs_key key;
8861         int err = 0;
8862         int ret;
8863         int level;
8864         bool root_dropped = false;
8865
8866         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
8867
8868         path = btrfs_alloc_path();
8869         if (!path) {
8870                 err = -ENOMEM;
8871                 goto out;
8872         }
8873
8874         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8875         if (!wc) {
8876                 btrfs_free_path(path);
8877                 err = -ENOMEM;
8878                 goto out;
8879         }
8880
8881         trans = btrfs_start_transaction(tree_root, 0);
8882         if (IS_ERR(trans)) {
8883                 err = PTR_ERR(trans);
8884                 goto out_free;
8885         }
8886
8887         if (block_rsv)
8888                 trans->block_rsv = block_rsv;
8889
8890         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8891                 level = btrfs_header_level(root->node);
8892                 path->nodes[level] = btrfs_lock_root_node(root);
8893                 btrfs_set_lock_blocking(path->nodes[level]);
8894                 path->slots[level] = 0;
8895                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8896                 memset(&wc->update_progress, 0,
8897                        sizeof(wc->update_progress));
8898         } else {
8899                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8900                 memcpy(&wc->update_progress, &key,
8901                        sizeof(wc->update_progress));
8902
8903                 level = root_item->drop_level;
8904                 BUG_ON(level == 0);
8905                 path->lowest_level = level;
8906                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8907                 path->lowest_level = 0;
8908                 if (ret < 0) {
8909                         err = ret;
8910                         goto out_end_trans;
8911                 }
8912                 WARN_ON(ret > 0);
8913
8914                 /*
8915                  * unlock our path, this is safe because only this
8916                  * function is allowed to delete this snapshot
8917                  */
8918                 btrfs_unlock_up_safe(path, 0);
8919
8920                 level = btrfs_header_level(root->node);
8921                 while (1) {
8922                         btrfs_tree_lock(path->nodes[level]);
8923                         btrfs_set_lock_blocking(path->nodes[level]);
8924                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8925
8926                         ret = btrfs_lookup_extent_info(trans, root,
8927                                                 path->nodes[level]->start,
8928                                                 level, 1, &wc->refs[level],
8929                                                 &wc->flags[level]);
8930                         if (ret < 0) {
8931                                 err = ret;
8932                                 goto out_end_trans;
8933                         }
8934                         BUG_ON(wc->refs[level] == 0);
8935
8936                         if (level == root_item->drop_level)
8937                                 break;
8938
8939                         btrfs_tree_unlock(path->nodes[level]);
8940                         path->locks[level] = 0;
8941                         WARN_ON(wc->refs[level] != 1);
8942                         level--;
8943                 }
8944         }
8945
8946         wc->level = level;
8947         wc->shared_level = -1;
8948         wc->stage = DROP_REFERENCE;
8949         wc->update_ref = update_ref;
8950         wc->keep_locks = 0;
8951         wc->for_reloc = for_reloc;
8952         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8953
8954         while (1) {
8955
8956                 ret = walk_down_tree(trans, root, path, wc);
8957                 if (ret < 0) {
8958                         err = ret;
8959                         break;
8960                 }
8961
8962                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8963                 if (ret < 0) {
8964                         err = ret;
8965                         break;
8966                 }
8967
8968                 if (ret > 0) {
8969                         BUG_ON(wc->stage != DROP_REFERENCE);
8970                         break;
8971                 }
8972
8973                 if (wc->stage == DROP_REFERENCE) {
8974                         level = wc->level;
8975                         btrfs_node_key(path->nodes[level],
8976                                        &root_item->drop_progress,
8977                                        path->slots[level]);
8978                         root_item->drop_level = level;
8979                 }
8980
8981                 BUG_ON(wc->level == 0);
8982                 if (btrfs_should_end_transaction(trans, tree_root) ||
8983                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
8984                         ret = btrfs_update_root(trans, tree_root,
8985                                                 &root->root_key,
8986                                                 root_item);
8987                         if (ret) {
8988                                 btrfs_abort_transaction(trans, tree_root, ret);
8989                                 err = ret;
8990                                 goto out_end_trans;
8991                         }
8992
8993                         btrfs_end_transaction_throttle(trans, tree_root);
8994                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
8995                                 pr_debug("BTRFS: drop snapshot early exit\n");
8996                                 err = -EAGAIN;
8997                                 goto out_free;
8998                         }
8999
9000                         trans = btrfs_start_transaction(tree_root, 0);
9001                         if (IS_ERR(trans)) {
9002                                 err = PTR_ERR(trans);
9003                                 goto out_free;
9004                         }
9005                         if (block_rsv)
9006                                 trans->block_rsv = block_rsv;
9007                 }
9008         }
9009         btrfs_release_path(path);
9010         if (err)
9011                 goto out_end_trans;
9012
9013         ret = btrfs_del_root(trans, tree_root, &root->root_key);
9014         if (ret) {
9015                 btrfs_abort_transaction(trans, tree_root, ret);
9016                 goto out_end_trans;
9017         }
9018
9019         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9020                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9021                                       NULL, NULL);
9022                 if (ret < 0) {
9023                         btrfs_abort_transaction(trans, tree_root, ret);
9024                         err = ret;
9025                         goto out_end_trans;
9026                 } else if (ret > 0) {
9027                         /* if we fail to delete the orphan item this time
9028                          * around, it'll get picked up the next time.
9029                          *
9030                          * The most common failure here is just -ENOENT.
9031                          */
9032                         btrfs_del_orphan_item(trans, tree_root,
9033                                               root->root_key.objectid);
9034                 }
9035         }
9036
9037         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9038                 btrfs_add_dropped_root(trans, root);
9039         } else {
9040                 free_extent_buffer(root->node);
9041                 free_extent_buffer(root->commit_root);
9042                 btrfs_put_fs_root(root);
9043         }
9044         root_dropped = true;
9045 out_end_trans:
9046         btrfs_end_transaction_throttle(trans, tree_root);
9047 out_free:
9048         kfree(wc);
9049         btrfs_free_path(path);
9050 out:
9051         /*
9052          * So if we need to stop dropping the snapshot for whatever reason we
9053          * need to make sure to add it back to the dead root list so that we
9054          * keep trying to do the work later.  This also cleans up roots if we
9055          * don't have it in the radix (like when we recover after a power fail
9056          * or unmount) so we don't leak memory.
9057          */
9058         if (!for_reloc && root_dropped == false)
9059                 btrfs_add_dead_root(root);
9060         if (err && err != -EAGAIN)
9061                 btrfs_std_error(root->fs_info, err, NULL);
9062         return err;
9063 }
9064
9065 /*
9066  * drop subtree rooted at tree block 'node'.
9067  *
9068  * NOTE: this function will unlock and release tree block 'node'
9069  * only used by relocation code
9070  */
9071 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9072                         struct btrfs_root *root,
9073                         struct extent_buffer *node,
9074                         struct extent_buffer *parent)
9075 {
9076         struct btrfs_path *path;
9077         struct walk_control *wc;
9078         int level;
9079         int parent_level;
9080         int ret = 0;
9081         int wret;
9082
9083         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9084
9085         path = btrfs_alloc_path();
9086         if (!path)
9087                 return -ENOMEM;
9088
9089         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9090         if (!wc) {
9091                 btrfs_free_path(path);
9092                 return -ENOMEM;
9093         }
9094
9095         btrfs_assert_tree_locked(parent);
9096         parent_level = btrfs_header_level(parent);
9097         extent_buffer_get(parent);
9098         path->nodes[parent_level] = parent;
9099         path->slots[parent_level] = btrfs_header_nritems(parent);
9100
9101         btrfs_assert_tree_locked(node);
9102         level = btrfs_header_level(node);
9103         path->nodes[level] = node;
9104         path->slots[level] = 0;
9105         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9106
9107         wc->refs[parent_level] = 1;
9108         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9109         wc->level = level;
9110         wc->shared_level = -1;
9111         wc->stage = DROP_REFERENCE;
9112         wc->update_ref = 0;
9113         wc->keep_locks = 1;
9114         wc->for_reloc = 1;
9115         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9116
9117         while (1) {
9118                 wret = walk_down_tree(trans, root, path, wc);
9119                 if (wret < 0) {
9120                         ret = wret;
9121                         break;
9122                 }
9123
9124                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9125                 if (wret < 0)
9126                         ret = wret;
9127                 if (wret != 0)
9128                         break;
9129         }
9130
9131         kfree(wc);
9132         btrfs_free_path(path);
9133         return ret;
9134 }
9135
9136 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
9137 {
9138         u64 num_devices;
9139         u64 stripped;
9140
9141         /*
9142          * if restripe for this chunk_type is on pick target profile and
9143          * return, otherwise do the usual balance
9144          */
9145         stripped = get_restripe_target(root->fs_info, flags);
9146         if (stripped)
9147                 return extended_to_chunk(stripped);
9148
9149         num_devices = root->fs_info->fs_devices->rw_devices;
9150
9151         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9152                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9153                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9154
9155         if (num_devices == 1) {
9156                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9157                 stripped = flags & ~stripped;
9158
9159                 /* turn raid0 into single device chunks */
9160                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9161                         return stripped;
9162
9163                 /* turn mirroring into duplication */
9164                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9165                              BTRFS_BLOCK_GROUP_RAID10))
9166                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9167         } else {
9168                 /* they already had raid on here, just return */
9169                 if (flags & stripped)
9170                         return flags;
9171
9172                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9173                 stripped = flags & ~stripped;
9174
9175                 /* switch duplicated blocks with raid1 */
9176                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9177                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9178
9179                 /* this is drive concat, leave it alone */
9180         }
9181
9182         return flags;
9183 }
9184
9185 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9186 {
9187         struct btrfs_space_info *sinfo = cache->space_info;
9188         u64 num_bytes;
9189         u64 min_allocable_bytes;
9190         int ret = -ENOSPC;
9191
9192         /*
9193          * We need some metadata space and system metadata space for
9194          * allocating chunks in some corner cases until we force to set
9195          * it to be readonly.
9196          */
9197         if ((sinfo->flags &
9198              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9199             !force)
9200                 min_allocable_bytes = SZ_1M;
9201         else
9202                 min_allocable_bytes = 0;
9203
9204         spin_lock(&sinfo->lock);
9205         spin_lock(&cache->lock);
9206
9207         if (cache->ro) {
9208                 cache->ro++;
9209                 ret = 0;
9210                 goto out;
9211         }
9212
9213         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9214                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9215
9216         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
9217             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
9218             min_allocable_bytes <= sinfo->total_bytes) {
9219                 sinfo->bytes_readonly += num_bytes;
9220                 cache->ro++;
9221                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9222                 ret = 0;
9223         }
9224 out:
9225         spin_unlock(&cache->lock);
9226         spin_unlock(&sinfo->lock);
9227         return ret;
9228 }
9229
9230 int btrfs_inc_block_group_ro(struct btrfs_root *root,
9231                              struct btrfs_block_group_cache *cache)
9232
9233 {
9234         struct btrfs_trans_handle *trans;
9235         u64 alloc_flags;
9236         int ret;
9237
9238 again:
9239         trans = btrfs_join_transaction(root);
9240         if (IS_ERR(trans))
9241                 return PTR_ERR(trans);
9242
9243         /*
9244          * we're not allowed to set block groups readonly after the dirty
9245          * block groups cache has started writing.  If it already started,
9246          * back off and let this transaction commit
9247          */
9248         mutex_lock(&root->fs_info->ro_block_group_mutex);
9249         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9250                 u64 transid = trans->transid;
9251
9252                 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9253                 btrfs_end_transaction(trans, root);
9254
9255                 ret = btrfs_wait_for_commit(root, transid);
9256                 if (ret)
9257                         return ret;
9258                 goto again;
9259         }
9260
9261         /*
9262          * if we are changing raid levels, try to allocate a corresponding
9263          * block group with the new raid level.
9264          */
9265         alloc_flags = update_block_group_flags(root, cache->flags);
9266         if (alloc_flags != cache->flags) {
9267                 ret = do_chunk_alloc(trans, root, alloc_flags,
9268                                      CHUNK_ALLOC_FORCE);
9269                 /*
9270                  * ENOSPC is allowed here, we may have enough space
9271                  * already allocated at the new raid level to
9272                  * carry on
9273                  */
9274                 if (ret == -ENOSPC)
9275                         ret = 0;
9276                 if (ret < 0)
9277                         goto out;
9278         }
9279
9280         ret = inc_block_group_ro(cache, 0);
9281         if (!ret)
9282                 goto out;
9283         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
9284         ret = do_chunk_alloc(trans, root, alloc_flags,
9285                              CHUNK_ALLOC_FORCE);
9286         if (ret < 0)
9287                 goto out;
9288         ret = inc_block_group_ro(cache, 0);
9289 out:
9290         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9291                 alloc_flags = update_block_group_flags(root, cache->flags);
9292                 lock_chunks(root->fs_info->chunk_root);
9293                 check_system_chunk(trans, root, alloc_flags);
9294                 unlock_chunks(root->fs_info->chunk_root);
9295         }
9296         mutex_unlock(&root->fs_info->ro_block_group_mutex);
9297
9298         btrfs_end_transaction(trans, root);
9299         return ret;
9300 }
9301
9302 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9303                             struct btrfs_root *root, u64 type)
9304 {
9305         u64 alloc_flags = get_alloc_profile(root, type);
9306         return do_chunk_alloc(trans, root, alloc_flags,
9307                               CHUNK_ALLOC_FORCE);
9308 }
9309
9310 /*
9311  * helper to account the unused space of all the readonly block group in the
9312  * space_info. takes mirrors into account.
9313  */
9314 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9315 {
9316         struct btrfs_block_group_cache *block_group;
9317         u64 free_bytes = 0;
9318         int factor;
9319
9320         /* It's df, we don't care if it's racey */
9321         if (list_empty(&sinfo->ro_bgs))
9322                 return 0;
9323
9324         spin_lock(&sinfo->lock);
9325         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9326                 spin_lock(&block_group->lock);
9327
9328                 if (!block_group->ro) {
9329                         spin_unlock(&block_group->lock);
9330                         continue;
9331                 }
9332
9333                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9334                                           BTRFS_BLOCK_GROUP_RAID10 |
9335                                           BTRFS_BLOCK_GROUP_DUP))
9336                         factor = 2;
9337                 else
9338                         factor = 1;
9339
9340                 free_bytes += (block_group->key.offset -
9341                                btrfs_block_group_used(&block_group->item)) *
9342                                factor;
9343
9344                 spin_unlock(&block_group->lock);
9345         }
9346         spin_unlock(&sinfo->lock);
9347
9348         return free_bytes;
9349 }
9350
9351 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9352                               struct btrfs_block_group_cache *cache)
9353 {
9354         struct btrfs_space_info *sinfo = cache->space_info;
9355         u64 num_bytes;
9356
9357         BUG_ON(!cache->ro);
9358
9359         spin_lock(&sinfo->lock);
9360         spin_lock(&cache->lock);
9361         if (!--cache->ro) {
9362                 num_bytes = cache->key.offset - cache->reserved -
9363                             cache->pinned - cache->bytes_super -
9364                             btrfs_block_group_used(&cache->item);
9365                 sinfo->bytes_readonly -= num_bytes;
9366                 list_del_init(&cache->ro_list);
9367         }
9368         spin_unlock(&cache->lock);
9369         spin_unlock(&sinfo->lock);
9370 }
9371
9372 /*
9373  * checks to see if its even possible to relocate this block group.
9374  *
9375  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9376  * ok to go ahead and try.
9377  */
9378 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9379 {
9380         struct btrfs_block_group_cache *block_group;
9381         struct btrfs_space_info *space_info;
9382         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9383         struct btrfs_device *device;
9384         struct btrfs_trans_handle *trans;
9385         u64 min_free;
9386         u64 dev_min = 1;
9387         u64 dev_nr = 0;
9388         u64 target;
9389         int debug;
9390         int index;
9391         int full = 0;
9392         int ret = 0;
9393
9394         debug = btrfs_test_opt(root, ENOSPC_DEBUG);
9395
9396         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9397
9398         /* odd, couldn't find the block group, leave it alone */
9399         if (!block_group) {
9400                 if (debug)
9401                         btrfs_warn(root->fs_info,
9402                                    "can't find block group for bytenr %llu",
9403                                    bytenr);
9404                 return -1;
9405         }
9406
9407         min_free = btrfs_block_group_used(&block_group->item);
9408
9409         /* no bytes used, we're good */
9410         if (!min_free)
9411                 goto out;
9412
9413         space_info = block_group->space_info;
9414         spin_lock(&space_info->lock);
9415
9416         full = space_info->full;
9417
9418         /*
9419          * if this is the last block group we have in this space, we can't
9420          * relocate it unless we're able to allocate a new chunk below.
9421          *
9422          * Otherwise, we need to make sure we have room in the space to handle
9423          * all of the extents from this block group.  If we can, we're good
9424          */
9425         if ((space_info->total_bytes != block_group->key.offset) &&
9426             (space_info->bytes_used + space_info->bytes_reserved +
9427              space_info->bytes_pinned + space_info->bytes_readonly +
9428              min_free < space_info->total_bytes)) {
9429                 spin_unlock(&space_info->lock);
9430                 goto out;
9431         }
9432         spin_unlock(&space_info->lock);
9433
9434         /*
9435          * ok we don't have enough space, but maybe we have free space on our
9436          * devices to allocate new chunks for relocation, so loop through our
9437          * alloc devices and guess if we have enough space.  if this block
9438          * group is going to be restriped, run checks against the target
9439          * profile instead of the current one.
9440          */
9441         ret = -1;
9442
9443         /*
9444          * index:
9445          *      0: raid10
9446          *      1: raid1
9447          *      2: dup
9448          *      3: raid0
9449          *      4: single
9450          */
9451         target = get_restripe_target(root->fs_info, block_group->flags);
9452         if (target) {
9453                 index = __get_raid_index(extended_to_chunk(target));
9454         } else {
9455                 /*
9456                  * this is just a balance, so if we were marked as full
9457                  * we know there is no space for a new chunk
9458                  */
9459                 if (full) {
9460                         if (debug)
9461                                 btrfs_warn(root->fs_info,
9462                                         "no space to alloc new chunk for block group %llu",
9463                                         block_group->key.objectid);
9464                         goto out;
9465                 }
9466
9467                 index = get_block_group_index(block_group);
9468         }
9469
9470         if (index == BTRFS_RAID_RAID10) {
9471                 dev_min = 4;
9472                 /* Divide by 2 */
9473                 min_free >>= 1;
9474         } else if (index == BTRFS_RAID_RAID1) {
9475                 dev_min = 2;
9476         } else if (index == BTRFS_RAID_DUP) {
9477                 /* Multiply by 2 */
9478                 min_free <<= 1;
9479         } else if (index == BTRFS_RAID_RAID0) {
9480                 dev_min = fs_devices->rw_devices;
9481                 min_free = div64_u64(min_free, dev_min);
9482         }
9483
9484         /* We need to do this so that we can look at pending chunks */
9485         trans = btrfs_join_transaction(root);
9486         if (IS_ERR(trans)) {
9487                 ret = PTR_ERR(trans);
9488                 goto out;
9489         }
9490
9491         mutex_lock(&root->fs_info->chunk_mutex);
9492         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9493                 u64 dev_offset;
9494
9495                 /*
9496                  * check to make sure we can actually find a chunk with enough
9497                  * space to fit our block group in.
9498                  */
9499                 if (device->total_bytes > device->bytes_used + min_free &&
9500                     !device->is_tgtdev_for_dev_replace) {
9501                         ret = find_free_dev_extent(trans, device, min_free,
9502                                                    &dev_offset, NULL);
9503                         if (!ret)
9504                                 dev_nr++;
9505
9506                         if (dev_nr >= dev_min)
9507                                 break;
9508
9509                         ret = -1;
9510                 }
9511         }
9512         if (debug && ret == -1)
9513                 btrfs_warn(root->fs_info,
9514                         "no space to allocate a new chunk for block group %llu",
9515                         block_group->key.objectid);
9516         mutex_unlock(&root->fs_info->chunk_mutex);
9517         btrfs_end_transaction(trans, root);
9518 out:
9519         btrfs_put_block_group(block_group);
9520         return ret;
9521 }
9522
9523 static int find_first_block_group(struct btrfs_root *root,
9524                 struct btrfs_path *path, struct btrfs_key *key)
9525 {
9526         int ret = 0;
9527         struct btrfs_key found_key;
9528         struct extent_buffer *leaf;
9529         int slot;
9530
9531         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9532         if (ret < 0)
9533                 goto out;
9534
9535         while (1) {
9536                 slot = path->slots[0];
9537                 leaf = path->nodes[0];
9538                 if (slot >= btrfs_header_nritems(leaf)) {
9539                         ret = btrfs_next_leaf(root, path);
9540                         if (ret == 0)
9541                                 continue;
9542                         if (ret < 0)
9543                                 goto out;
9544                         break;
9545                 }
9546                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9547
9548                 if (found_key.objectid >= key->objectid &&
9549                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9550                         ret = 0;
9551                         goto out;
9552                 }
9553                 path->slots[0]++;
9554         }
9555 out:
9556         return ret;
9557 }
9558
9559 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9560 {
9561         struct btrfs_block_group_cache *block_group;
9562         u64 last = 0;
9563
9564         while (1) {
9565                 struct inode *inode;
9566
9567                 block_group = btrfs_lookup_first_block_group(info, last);
9568                 while (block_group) {
9569                         spin_lock(&block_group->lock);
9570                         if (block_group->iref)
9571                                 break;
9572                         spin_unlock(&block_group->lock);
9573                         block_group = next_block_group(info->tree_root,
9574                                                        block_group);
9575                 }
9576                 if (!block_group) {
9577                         if (last == 0)
9578                                 break;
9579                         last = 0;
9580                         continue;
9581                 }
9582
9583                 inode = block_group->inode;
9584                 block_group->iref = 0;
9585                 block_group->inode = NULL;
9586                 spin_unlock(&block_group->lock);
9587                 iput(inode);
9588                 last = block_group->key.objectid + block_group->key.offset;
9589                 btrfs_put_block_group(block_group);
9590         }
9591 }
9592
9593 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9594 {
9595         struct btrfs_block_group_cache *block_group;
9596         struct btrfs_space_info *space_info;
9597         struct btrfs_caching_control *caching_ctl;
9598         struct rb_node *n;
9599
9600         down_write(&info->commit_root_sem);
9601         while (!list_empty(&info->caching_block_groups)) {
9602                 caching_ctl = list_entry(info->caching_block_groups.next,
9603                                          struct btrfs_caching_control, list);
9604                 list_del(&caching_ctl->list);
9605                 put_caching_control(caching_ctl);
9606         }
9607         up_write(&info->commit_root_sem);
9608
9609         spin_lock(&info->unused_bgs_lock);
9610         while (!list_empty(&info->unused_bgs)) {
9611                 block_group = list_first_entry(&info->unused_bgs,
9612                                                struct btrfs_block_group_cache,
9613                                                bg_list);
9614                 list_del_init(&block_group->bg_list);
9615                 btrfs_put_block_group(block_group);
9616         }
9617         spin_unlock(&info->unused_bgs_lock);
9618
9619         spin_lock(&info->block_group_cache_lock);
9620         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9621                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9622                                        cache_node);
9623                 rb_erase(&block_group->cache_node,
9624                          &info->block_group_cache_tree);
9625                 RB_CLEAR_NODE(&block_group->cache_node);
9626                 spin_unlock(&info->block_group_cache_lock);
9627
9628                 down_write(&block_group->space_info->groups_sem);
9629                 list_del(&block_group->list);
9630                 up_write(&block_group->space_info->groups_sem);
9631
9632                 if (block_group->cached == BTRFS_CACHE_STARTED)
9633                         wait_block_group_cache_done(block_group);
9634
9635                 /*
9636                  * We haven't cached this block group, which means we could
9637                  * possibly have excluded extents on this block group.
9638                  */
9639                 if (block_group->cached == BTRFS_CACHE_NO ||
9640                     block_group->cached == BTRFS_CACHE_ERROR)
9641                         free_excluded_extents(info->extent_root, block_group);
9642
9643                 btrfs_remove_free_space_cache(block_group);
9644                 btrfs_put_block_group(block_group);
9645
9646                 spin_lock(&info->block_group_cache_lock);
9647         }
9648         spin_unlock(&info->block_group_cache_lock);
9649
9650         /* now that all the block groups are freed, go through and
9651          * free all the space_info structs.  This is only called during
9652          * the final stages of unmount, and so we know nobody is
9653          * using them.  We call synchronize_rcu() once before we start,
9654          * just to be on the safe side.
9655          */
9656         synchronize_rcu();
9657
9658         release_global_block_rsv(info);
9659
9660         while (!list_empty(&info->space_info)) {
9661                 int i;
9662
9663                 space_info = list_entry(info->space_info.next,
9664                                         struct btrfs_space_info,
9665                                         list);
9666                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
9667                         if (WARN_ON(space_info->bytes_pinned > 0 ||
9668                             space_info->bytes_reserved > 0 ||
9669                             space_info->bytes_may_use > 0)) {
9670                                 dump_space_info(space_info, 0, 0);
9671                         }
9672                 }
9673                 list_del(&space_info->list);
9674                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9675                         struct kobject *kobj;
9676                         kobj = space_info->block_group_kobjs[i];
9677                         space_info->block_group_kobjs[i] = NULL;
9678                         if (kobj) {
9679                                 kobject_del(kobj);
9680                                 kobject_put(kobj);
9681                         }
9682                 }
9683                 kobject_del(&space_info->kobj);
9684                 kobject_put(&space_info->kobj);
9685         }
9686         return 0;
9687 }
9688
9689 static void __link_block_group(struct btrfs_space_info *space_info,
9690                                struct btrfs_block_group_cache *cache)
9691 {
9692         int index = get_block_group_index(cache);
9693         bool first = false;
9694
9695         down_write(&space_info->groups_sem);
9696         if (list_empty(&space_info->block_groups[index]))
9697                 first = true;
9698         list_add_tail(&cache->list, &space_info->block_groups[index]);
9699         up_write(&space_info->groups_sem);
9700
9701         if (first) {
9702                 struct raid_kobject *rkobj;
9703                 int ret;
9704
9705                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9706                 if (!rkobj)
9707                         goto out_err;
9708                 rkobj->raid_type = index;
9709                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9710                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9711                                   "%s", get_raid_name(index));
9712                 if (ret) {
9713                         kobject_put(&rkobj->kobj);
9714                         goto out_err;
9715                 }
9716                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9717         }
9718
9719         return;
9720 out_err:
9721         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
9722 }
9723
9724 static struct btrfs_block_group_cache *
9725 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
9726 {
9727         struct btrfs_block_group_cache *cache;
9728
9729         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9730         if (!cache)
9731                 return NULL;
9732
9733         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9734                                         GFP_NOFS);
9735         if (!cache->free_space_ctl) {
9736                 kfree(cache);
9737                 return NULL;
9738         }
9739
9740         cache->key.objectid = start;
9741         cache->key.offset = size;
9742         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9743
9744         cache->sectorsize = root->sectorsize;
9745         cache->fs_info = root->fs_info;
9746         cache->full_stripe_len = btrfs_full_stripe_len(root,
9747                                                &root->fs_info->mapping_tree,
9748                                                start);
9749         set_free_space_tree_thresholds(cache);
9750
9751         atomic_set(&cache->count, 1);
9752         spin_lock_init(&cache->lock);
9753         init_rwsem(&cache->data_rwsem);
9754         INIT_LIST_HEAD(&cache->list);
9755         INIT_LIST_HEAD(&cache->cluster_list);
9756         INIT_LIST_HEAD(&cache->bg_list);
9757         INIT_LIST_HEAD(&cache->ro_list);
9758         INIT_LIST_HEAD(&cache->dirty_list);
9759         INIT_LIST_HEAD(&cache->io_list);
9760         btrfs_init_free_space_ctl(cache);
9761         atomic_set(&cache->trimming, 0);
9762         mutex_init(&cache->free_space_lock);
9763
9764         return cache;
9765 }
9766
9767 int btrfs_read_block_groups(struct btrfs_root *root)
9768 {
9769         struct btrfs_path *path;
9770         int ret;
9771         struct btrfs_block_group_cache *cache;
9772         struct btrfs_fs_info *info = root->fs_info;
9773         struct btrfs_space_info *space_info;
9774         struct btrfs_key key;
9775         struct btrfs_key found_key;
9776         struct extent_buffer *leaf;
9777         int need_clear = 0;
9778         u64 cache_gen;
9779
9780         root = info->extent_root;
9781         key.objectid = 0;
9782         key.offset = 0;
9783         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9784         path = btrfs_alloc_path();
9785         if (!path)
9786                 return -ENOMEM;
9787         path->reada = READA_FORWARD;
9788
9789         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
9790         if (btrfs_test_opt(root, SPACE_CACHE) &&
9791             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
9792                 need_clear = 1;
9793         if (btrfs_test_opt(root, CLEAR_CACHE))
9794                 need_clear = 1;
9795
9796         while (1) {
9797                 ret = find_first_block_group(root, path, &key);
9798                 if (ret > 0)
9799                         break;
9800                 if (ret != 0)
9801                         goto error;
9802
9803                 leaf = path->nodes[0];
9804                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9805
9806                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
9807                                                        found_key.offset);
9808                 if (!cache) {
9809                         ret = -ENOMEM;
9810                         goto error;
9811                 }
9812
9813                 if (need_clear) {
9814                         /*
9815                          * When we mount with old space cache, we need to
9816                          * set BTRFS_DC_CLEAR and set dirty flag.
9817                          *
9818                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9819                          *    truncate the old free space cache inode and
9820                          *    setup a new one.
9821                          * b) Setting 'dirty flag' makes sure that we flush
9822                          *    the new space cache info onto disk.
9823                          */
9824                         if (btrfs_test_opt(root, SPACE_CACHE))
9825                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9826                 }
9827
9828                 read_extent_buffer(leaf, &cache->item,
9829                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9830                                    sizeof(cache->item));
9831                 cache->flags = btrfs_block_group_flags(&cache->item);
9832
9833                 key.objectid = found_key.objectid + found_key.offset;
9834                 btrfs_release_path(path);
9835
9836                 /*
9837                  * We need to exclude the super stripes now so that the space
9838                  * info has super bytes accounted for, otherwise we'll think
9839                  * we have more space than we actually do.
9840                  */
9841                 ret = exclude_super_stripes(root, cache);
9842                 if (ret) {
9843                         /*
9844                          * We may have excluded something, so call this just in
9845                          * case.
9846                          */
9847                         free_excluded_extents(root, cache);
9848                         btrfs_put_block_group(cache);
9849                         goto error;
9850                 }
9851
9852                 /*
9853                  * check for two cases, either we are full, and therefore
9854                  * don't need to bother with the caching work since we won't
9855                  * find any space, or we are empty, and we can just add all
9856                  * the space in and be done with it.  This saves us _alot_ of
9857                  * time, particularly in the full case.
9858                  */
9859                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
9860                         cache->last_byte_to_unpin = (u64)-1;
9861                         cache->cached = BTRFS_CACHE_FINISHED;
9862                         free_excluded_extents(root, cache);
9863                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9864                         cache->last_byte_to_unpin = (u64)-1;
9865                         cache->cached = BTRFS_CACHE_FINISHED;
9866                         add_new_free_space(cache, root->fs_info,
9867                                            found_key.objectid,
9868                                            found_key.objectid +
9869                                            found_key.offset);
9870                         free_excluded_extents(root, cache);
9871                 }
9872
9873                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
9874                 if (ret) {
9875                         btrfs_remove_free_space_cache(cache);
9876                         btrfs_put_block_group(cache);
9877                         goto error;
9878                 }
9879
9880                 ret = update_space_info(info, cache->flags, found_key.offset,
9881                                         btrfs_block_group_used(&cache->item),
9882                                         &space_info);
9883                 if (ret) {
9884                         btrfs_remove_free_space_cache(cache);
9885                         spin_lock(&info->block_group_cache_lock);
9886                         rb_erase(&cache->cache_node,
9887                                  &info->block_group_cache_tree);
9888                         RB_CLEAR_NODE(&cache->cache_node);
9889                         spin_unlock(&info->block_group_cache_lock);
9890                         btrfs_put_block_group(cache);
9891                         goto error;
9892                 }
9893
9894                 cache->space_info = space_info;
9895                 spin_lock(&cache->space_info->lock);
9896                 cache->space_info->bytes_readonly += cache->bytes_super;
9897                 spin_unlock(&cache->space_info->lock);
9898
9899                 __link_block_group(space_info, cache);
9900
9901                 set_avail_alloc_bits(root->fs_info, cache->flags);
9902                 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
9903                         inc_block_group_ro(cache, 1);
9904                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9905                         spin_lock(&info->unused_bgs_lock);
9906                         /* Should always be true but just in case. */
9907                         if (list_empty(&cache->bg_list)) {
9908                                 btrfs_get_block_group(cache);
9909                                 list_add_tail(&cache->bg_list,
9910                                               &info->unused_bgs);
9911                         }
9912                         spin_unlock(&info->unused_bgs_lock);
9913                 }
9914         }
9915
9916         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
9917                 if (!(get_alloc_profile(root, space_info->flags) &
9918                       (BTRFS_BLOCK_GROUP_RAID10 |
9919                        BTRFS_BLOCK_GROUP_RAID1 |
9920                        BTRFS_BLOCK_GROUP_RAID5 |
9921                        BTRFS_BLOCK_GROUP_RAID6 |
9922                        BTRFS_BLOCK_GROUP_DUP)))
9923                         continue;
9924                 /*
9925                  * avoid allocating from un-mirrored block group if there are
9926                  * mirrored block groups.
9927                  */
9928                 list_for_each_entry(cache,
9929                                 &space_info->block_groups[BTRFS_RAID_RAID0],
9930                                 list)
9931                         inc_block_group_ro(cache, 1);
9932                 list_for_each_entry(cache,
9933                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
9934                                 list)
9935                         inc_block_group_ro(cache, 1);
9936         }
9937
9938         init_global_block_rsv(info);
9939         ret = 0;
9940 error:
9941         btrfs_free_path(path);
9942         return ret;
9943 }
9944
9945 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
9946                                        struct btrfs_root *root)
9947 {
9948         struct btrfs_block_group_cache *block_group, *tmp;
9949         struct btrfs_root *extent_root = root->fs_info->extent_root;
9950         struct btrfs_block_group_item item;
9951         struct btrfs_key key;
9952         int ret = 0;
9953         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
9954
9955         trans->can_flush_pending_bgs = false;
9956         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
9957                 if (ret)
9958                         goto next;
9959
9960                 spin_lock(&block_group->lock);
9961                 memcpy(&item, &block_group->item, sizeof(item));
9962                 memcpy(&key, &block_group->key, sizeof(key));
9963                 spin_unlock(&block_group->lock);
9964
9965                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
9966                                         sizeof(item));
9967                 if (ret)
9968                         btrfs_abort_transaction(trans, extent_root, ret);
9969                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
9970                                                key.objectid, key.offset);
9971                 if (ret)
9972                         btrfs_abort_transaction(trans, extent_root, ret);
9973                 add_block_group_free_space(trans, root->fs_info, block_group);
9974                 /* already aborted the transaction if it failed. */
9975 next:
9976                 list_del_init(&block_group->bg_list);
9977         }
9978         trans->can_flush_pending_bgs = can_flush_pending_bgs;
9979 }
9980
9981 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
9982                            struct btrfs_root *root, u64 bytes_used,
9983                            u64 type, u64 chunk_objectid, u64 chunk_offset,
9984                            u64 size)
9985 {
9986         int ret;
9987         struct btrfs_root *extent_root;
9988         struct btrfs_block_group_cache *cache;
9989
9990         extent_root = root->fs_info->extent_root;
9991
9992         btrfs_set_log_full_commit(root->fs_info, trans);
9993
9994         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
9995         if (!cache)
9996                 return -ENOMEM;
9997
9998         btrfs_set_block_group_used(&cache->item, bytes_used);
9999         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
10000         btrfs_set_block_group_flags(&cache->item, type);
10001
10002         cache->flags = type;
10003         cache->last_byte_to_unpin = (u64)-1;
10004         cache->cached = BTRFS_CACHE_FINISHED;
10005         cache->needs_free_space = 1;
10006         ret = exclude_super_stripes(root, cache);
10007         if (ret) {
10008                 /*
10009                  * We may have excluded something, so call this just in
10010                  * case.
10011                  */
10012                 free_excluded_extents(root, cache);
10013                 btrfs_put_block_group(cache);
10014                 return ret;
10015         }
10016
10017         add_new_free_space(cache, root->fs_info, chunk_offset,
10018                            chunk_offset + size);
10019
10020         free_excluded_extents(root, cache);
10021
10022 #ifdef CONFIG_BTRFS_DEBUG
10023         if (btrfs_should_fragment_free_space(root, cache)) {
10024                 u64 new_bytes_used = size - bytes_used;
10025
10026                 bytes_used += new_bytes_used >> 1;
10027                 fragment_free_space(root, cache);
10028         }
10029 #endif
10030         /*
10031          * Call to ensure the corresponding space_info object is created and
10032          * assigned to our block group, but don't update its counters just yet.
10033          * We want our bg to be added to the rbtree with its ->space_info set.
10034          */
10035         ret = update_space_info(root->fs_info, cache->flags, 0, 0,
10036                                 &cache->space_info);
10037         if (ret) {
10038                 btrfs_remove_free_space_cache(cache);
10039                 btrfs_put_block_group(cache);
10040                 return ret;
10041         }
10042
10043         ret = btrfs_add_block_group_cache(root->fs_info, cache);
10044         if (ret) {
10045                 btrfs_remove_free_space_cache(cache);
10046                 btrfs_put_block_group(cache);
10047                 return ret;
10048         }
10049
10050         /*
10051          * Now that our block group has its ->space_info set and is inserted in
10052          * the rbtree, update the space info's counters.
10053          */
10054         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
10055                                 &cache->space_info);
10056         if (ret) {
10057                 btrfs_remove_free_space_cache(cache);
10058                 spin_lock(&root->fs_info->block_group_cache_lock);
10059                 rb_erase(&cache->cache_node,
10060                          &root->fs_info->block_group_cache_tree);
10061                 RB_CLEAR_NODE(&cache->cache_node);
10062                 spin_unlock(&root->fs_info->block_group_cache_lock);
10063                 btrfs_put_block_group(cache);
10064                 return ret;
10065         }
10066         update_global_block_rsv(root->fs_info);
10067
10068         spin_lock(&cache->space_info->lock);
10069         cache->space_info->bytes_readonly += cache->bytes_super;
10070         spin_unlock(&cache->space_info->lock);
10071
10072         __link_block_group(cache->space_info, cache);
10073
10074         list_add_tail(&cache->bg_list, &trans->new_bgs);
10075
10076         set_avail_alloc_bits(extent_root->fs_info, type);
10077
10078         return 0;
10079 }
10080
10081 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10082 {
10083         u64 extra_flags = chunk_to_extended(flags) &
10084                                 BTRFS_EXTENDED_PROFILE_MASK;
10085
10086         write_seqlock(&fs_info->profiles_lock);
10087         if (flags & BTRFS_BLOCK_GROUP_DATA)
10088                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10089         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10090                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10091         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10092                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10093         write_sequnlock(&fs_info->profiles_lock);
10094 }
10095
10096 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10097                              struct btrfs_root *root, u64 group_start,
10098                              struct extent_map *em)
10099 {
10100         struct btrfs_path *path;
10101         struct btrfs_block_group_cache *block_group;
10102         struct btrfs_free_cluster *cluster;
10103         struct btrfs_root *tree_root = root->fs_info->tree_root;
10104         struct btrfs_key key;
10105         struct inode *inode;
10106         struct kobject *kobj = NULL;
10107         int ret;
10108         int index;
10109         int factor;
10110         struct btrfs_caching_control *caching_ctl = NULL;
10111         bool remove_em;
10112
10113         root = root->fs_info->extent_root;
10114
10115         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
10116         BUG_ON(!block_group);
10117         BUG_ON(!block_group->ro);
10118
10119         /*
10120          * Free the reserved super bytes from this block group before
10121          * remove it.
10122          */
10123         free_excluded_extents(root, block_group);
10124
10125         memcpy(&key, &block_group->key, sizeof(key));
10126         index = get_block_group_index(block_group);
10127         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10128                                   BTRFS_BLOCK_GROUP_RAID1 |
10129                                   BTRFS_BLOCK_GROUP_RAID10))
10130                 factor = 2;
10131         else
10132                 factor = 1;
10133
10134         /* make sure this block group isn't part of an allocation cluster */
10135         cluster = &root->fs_info->data_alloc_cluster;
10136         spin_lock(&cluster->refill_lock);
10137         btrfs_return_cluster_to_free_space(block_group, cluster);
10138         spin_unlock(&cluster->refill_lock);
10139
10140         /*
10141          * make sure this block group isn't part of a metadata
10142          * allocation cluster
10143          */
10144         cluster = &root->fs_info->meta_alloc_cluster;
10145         spin_lock(&cluster->refill_lock);
10146         btrfs_return_cluster_to_free_space(block_group, cluster);
10147         spin_unlock(&cluster->refill_lock);
10148
10149         path = btrfs_alloc_path();
10150         if (!path) {
10151                 ret = -ENOMEM;
10152                 goto out;
10153         }
10154
10155         /*
10156          * get the inode first so any iput calls done for the io_list
10157          * aren't the final iput (no unlinks allowed now)
10158          */
10159         inode = lookup_free_space_inode(tree_root, block_group, path);
10160
10161         mutex_lock(&trans->transaction->cache_write_mutex);
10162         /*
10163          * make sure our free spache cache IO is done before remove the
10164          * free space inode
10165          */
10166         spin_lock(&trans->transaction->dirty_bgs_lock);
10167         if (!list_empty(&block_group->io_list)) {
10168                 list_del_init(&block_group->io_list);
10169
10170                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10171
10172                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10173                 btrfs_wait_cache_io(root, trans, block_group,
10174                                     &block_group->io_ctl, path,
10175                                     block_group->key.objectid);
10176                 btrfs_put_block_group(block_group);
10177                 spin_lock(&trans->transaction->dirty_bgs_lock);
10178         }
10179
10180         if (!list_empty(&block_group->dirty_list)) {
10181                 list_del_init(&block_group->dirty_list);
10182                 btrfs_put_block_group(block_group);
10183         }
10184         spin_unlock(&trans->transaction->dirty_bgs_lock);
10185         mutex_unlock(&trans->transaction->cache_write_mutex);
10186
10187         if (!IS_ERR(inode)) {
10188                 ret = btrfs_orphan_add(trans, inode);
10189                 if (ret) {
10190                         btrfs_add_delayed_iput(inode);
10191                         goto out;
10192                 }
10193                 clear_nlink(inode);
10194                 /* One for the block groups ref */
10195                 spin_lock(&block_group->lock);
10196                 if (block_group->iref) {
10197                         block_group->iref = 0;
10198                         block_group->inode = NULL;
10199                         spin_unlock(&block_group->lock);
10200                         iput(inode);
10201                 } else {
10202                         spin_unlock(&block_group->lock);
10203                 }
10204                 /* One for our lookup ref */
10205                 btrfs_add_delayed_iput(inode);
10206         }
10207
10208         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10209         key.offset = block_group->key.objectid;
10210         key.type = 0;
10211
10212         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10213         if (ret < 0)
10214                 goto out;
10215         if (ret > 0)
10216                 btrfs_release_path(path);
10217         if (ret == 0) {
10218                 ret = btrfs_del_item(trans, tree_root, path);
10219                 if (ret)
10220                         goto out;
10221                 btrfs_release_path(path);
10222         }
10223
10224         spin_lock(&root->fs_info->block_group_cache_lock);
10225         rb_erase(&block_group->cache_node,
10226                  &root->fs_info->block_group_cache_tree);
10227         RB_CLEAR_NODE(&block_group->cache_node);
10228
10229         if (root->fs_info->first_logical_byte == block_group->key.objectid)
10230                 root->fs_info->first_logical_byte = (u64)-1;
10231         spin_unlock(&root->fs_info->block_group_cache_lock);
10232
10233         down_write(&block_group->space_info->groups_sem);
10234         /*
10235          * we must use list_del_init so people can check to see if they
10236          * are still on the list after taking the semaphore
10237          */
10238         list_del_init(&block_group->list);
10239         if (list_empty(&block_group->space_info->block_groups[index])) {
10240                 kobj = block_group->space_info->block_group_kobjs[index];
10241                 block_group->space_info->block_group_kobjs[index] = NULL;
10242                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
10243         }
10244         up_write(&block_group->space_info->groups_sem);
10245         if (kobj) {
10246                 kobject_del(kobj);
10247                 kobject_put(kobj);
10248         }
10249
10250         if (block_group->has_caching_ctl)
10251                 caching_ctl = get_caching_control(block_group);
10252         if (block_group->cached == BTRFS_CACHE_STARTED)
10253                 wait_block_group_cache_done(block_group);
10254         if (block_group->has_caching_ctl) {
10255                 down_write(&root->fs_info->commit_root_sem);
10256                 if (!caching_ctl) {
10257                         struct btrfs_caching_control *ctl;
10258
10259                         list_for_each_entry(ctl,
10260                                     &root->fs_info->caching_block_groups, list)
10261                                 if (ctl->block_group == block_group) {
10262                                         caching_ctl = ctl;
10263                                         atomic_inc(&caching_ctl->count);
10264                                         break;
10265                                 }
10266                 }
10267                 if (caching_ctl)
10268                         list_del_init(&caching_ctl->list);
10269                 up_write(&root->fs_info->commit_root_sem);
10270                 if (caching_ctl) {
10271                         /* Once for the caching bgs list and once for us. */
10272                         put_caching_control(caching_ctl);
10273                         put_caching_control(caching_ctl);
10274                 }
10275         }
10276
10277         spin_lock(&trans->transaction->dirty_bgs_lock);
10278         if (!list_empty(&block_group->dirty_list)) {
10279                 WARN_ON(1);
10280         }
10281         if (!list_empty(&block_group->io_list)) {
10282                 WARN_ON(1);
10283         }
10284         spin_unlock(&trans->transaction->dirty_bgs_lock);
10285         btrfs_remove_free_space_cache(block_group);
10286
10287         spin_lock(&block_group->space_info->lock);
10288         list_del_init(&block_group->ro_list);
10289
10290         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
10291                 WARN_ON(block_group->space_info->total_bytes
10292                         < block_group->key.offset);
10293                 WARN_ON(block_group->space_info->bytes_readonly
10294                         < block_group->key.offset);
10295                 WARN_ON(block_group->space_info->disk_total
10296                         < block_group->key.offset * factor);
10297         }
10298         block_group->space_info->total_bytes -= block_group->key.offset;
10299         block_group->space_info->bytes_readonly -= block_group->key.offset;
10300         block_group->space_info->disk_total -= block_group->key.offset * factor;
10301
10302         spin_unlock(&block_group->space_info->lock);
10303
10304         memcpy(&key, &block_group->key, sizeof(key));
10305
10306         lock_chunks(root);
10307         if (!list_empty(&em->list)) {
10308                 /* We're in the transaction->pending_chunks list. */
10309                 free_extent_map(em);
10310         }
10311         spin_lock(&block_group->lock);
10312         block_group->removed = 1;
10313         /*
10314          * At this point trimming can't start on this block group, because we
10315          * removed the block group from the tree fs_info->block_group_cache_tree
10316          * so no one can't find it anymore and even if someone already got this
10317          * block group before we removed it from the rbtree, they have already
10318          * incremented block_group->trimming - if they didn't, they won't find
10319          * any free space entries because we already removed them all when we
10320          * called btrfs_remove_free_space_cache().
10321          *
10322          * And we must not remove the extent map from the fs_info->mapping_tree
10323          * to prevent the same logical address range and physical device space
10324          * ranges from being reused for a new block group. This is because our
10325          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10326          * completely transactionless, so while it is trimming a range the
10327          * currently running transaction might finish and a new one start,
10328          * allowing for new block groups to be created that can reuse the same
10329          * physical device locations unless we take this special care.
10330          *
10331          * There may also be an implicit trim operation if the file system
10332          * is mounted with -odiscard. The same protections must remain
10333          * in place until the extents have been discarded completely when
10334          * the transaction commit has completed.
10335          */
10336         remove_em = (atomic_read(&block_group->trimming) == 0);
10337         /*
10338          * Make sure a trimmer task always sees the em in the pinned_chunks list
10339          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10340          * before checking block_group->removed).
10341          */
10342         if (!remove_em) {
10343                 /*
10344                  * Our em might be in trans->transaction->pending_chunks which
10345                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10346                  * and so is the fs_info->pinned_chunks list.
10347                  *
10348                  * So at this point we must be holding the chunk_mutex to avoid
10349                  * any races with chunk allocation (more specifically at
10350                  * volumes.c:contains_pending_extent()), to ensure it always
10351                  * sees the em, either in the pending_chunks list or in the
10352                  * pinned_chunks list.
10353                  */
10354                 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10355         }
10356         spin_unlock(&block_group->lock);
10357
10358         if (remove_em) {
10359                 struct extent_map_tree *em_tree;
10360
10361                 em_tree = &root->fs_info->mapping_tree.map_tree;
10362                 write_lock(&em_tree->lock);
10363                 /*
10364                  * The em might be in the pending_chunks list, so make sure the
10365                  * chunk mutex is locked, since remove_extent_mapping() will
10366                  * delete us from that list.
10367                  */
10368                 remove_extent_mapping(em_tree, em);
10369                 write_unlock(&em_tree->lock);
10370                 /* once for the tree */
10371                 free_extent_map(em);
10372         }
10373
10374         unlock_chunks(root);
10375
10376         ret = remove_block_group_free_space(trans, root->fs_info, block_group);
10377         if (ret)
10378                 goto out;
10379
10380         btrfs_put_block_group(block_group);
10381         btrfs_put_block_group(block_group);
10382
10383         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10384         if (ret > 0)
10385                 ret = -EIO;
10386         if (ret < 0)
10387                 goto out;
10388
10389         ret = btrfs_del_item(trans, root, path);
10390 out:
10391         btrfs_free_path(path);
10392         return ret;
10393 }
10394
10395 struct btrfs_trans_handle *
10396 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10397                                      const u64 chunk_offset)
10398 {
10399         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10400         struct extent_map *em;
10401         struct map_lookup *map;
10402         unsigned int num_items;
10403
10404         read_lock(&em_tree->lock);
10405         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10406         read_unlock(&em_tree->lock);
10407         ASSERT(em && em->start == chunk_offset);
10408
10409         /*
10410          * We need to reserve 3 + N units from the metadata space info in order
10411          * to remove a block group (done at btrfs_remove_chunk() and at
10412          * btrfs_remove_block_group()), which are used for:
10413          *
10414          * 1 unit for adding the free space inode's orphan (located in the tree
10415          * of tree roots).
10416          * 1 unit for deleting the block group item (located in the extent
10417          * tree).
10418          * 1 unit for deleting the free space item (located in tree of tree
10419          * roots).
10420          * N units for deleting N device extent items corresponding to each
10421          * stripe (located in the device tree).
10422          *
10423          * In order to remove a block group we also need to reserve units in the
10424          * system space info in order to update the chunk tree (update one or
10425          * more device items and remove one chunk item), but this is done at
10426          * btrfs_remove_chunk() through a call to check_system_chunk().
10427          */
10428         map = em->map_lookup;
10429         num_items = 3 + map->num_stripes;
10430         free_extent_map(em);
10431
10432         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10433                                                            num_items, 1);
10434 }
10435
10436 /*
10437  * Process the unused_bgs list and remove any that don't have any allocated
10438  * space inside of them.
10439  */
10440 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10441 {
10442         struct btrfs_block_group_cache *block_group;
10443         struct btrfs_space_info *space_info;
10444         struct btrfs_root *root = fs_info->extent_root;
10445         struct btrfs_trans_handle *trans;
10446         int ret = 0;
10447
10448         if (!fs_info->open)
10449                 return;
10450
10451         spin_lock(&fs_info->unused_bgs_lock);
10452         while (!list_empty(&fs_info->unused_bgs)) {
10453                 u64 start, end;
10454                 int trimming;
10455
10456                 block_group = list_first_entry(&fs_info->unused_bgs,
10457                                                struct btrfs_block_group_cache,
10458                                                bg_list);
10459                 list_del_init(&block_group->bg_list);
10460
10461                 space_info = block_group->space_info;
10462
10463                 if (ret || btrfs_mixed_space_info(space_info)) {
10464                         btrfs_put_block_group(block_group);
10465                         continue;
10466                 }
10467                 spin_unlock(&fs_info->unused_bgs_lock);
10468
10469                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10470
10471                 /* Don't want to race with allocators so take the groups_sem */
10472                 down_write(&space_info->groups_sem);
10473                 spin_lock(&block_group->lock);
10474                 if (block_group->reserved ||
10475                     btrfs_block_group_used(&block_group->item) ||
10476                     block_group->ro ||
10477                     list_is_singular(&block_group->list)) {
10478                         /*
10479                          * We want to bail if we made new allocations or have
10480                          * outstanding allocations in this block group.  We do
10481                          * the ro check in case balance is currently acting on
10482                          * this block group.
10483                          */
10484                         spin_unlock(&block_group->lock);
10485                         up_write(&space_info->groups_sem);
10486                         goto next;
10487                 }
10488                 spin_unlock(&block_group->lock);
10489
10490                 /* We don't want to force the issue, only flip if it's ok. */
10491                 ret = inc_block_group_ro(block_group, 0);
10492                 up_write(&space_info->groups_sem);
10493                 if (ret < 0) {
10494                         ret = 0;
10495                         goto next;
10496                 }
10497
10498                 /*
10499                  * Want to do this before we do anything else so we can recover
10500                  * properly if we fail to join the transaction.
10501                  */
10502                 trans = btrfs_start_trans_remove_block_group(fs_info,
10503                                                      block_group->key.objectid);
10504                 if (IS_ERR(trans)) {
10505                         btrfs_dec_block_group_ro(root, block_group);
10506                         ret = PTR_ERR(trans);
10507                         goto next;
10508                 }
10509
10510                 /*
10511                  * We could have pending pinned extents for this block group,
10512                  * just delete them, we don't care about them anymore.
10513                  */
10514                 start = block_group->key.objectid;
10515                 end = start + block_group->key.offset - 1;
10516                 /*
10517                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10518                  * btrfs_finish_extent_commit(). If we are at transaction N,
10519                  * another task might be running finish_extent_commit() for the
10520                  * previous transaction N - 1, and have seen a range belonging
10521                  * to the block group in freed_extents[] before we were able to
10522                  * clear the whole block group range from freed_extents[]. This
10523                  * means that task can lookup for the block group after we
10524                  * unpinned it from freed_extents[] and removed it, leading to
10525                  * a BUG_ON() at btrfs_unpin_extent_range().
10526                  */
10527                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10528                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10529                                   EXTENT_DIRTY, GFP_NOFS);
10530                 if (ret) {
10531                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10532                         btrfs_dec_block_group_ro(root, block_group);
10533                         goto end_trans;
10534                 }
10535                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10536                                   EXTENT_DIRTY, GFP_NOFS);
10537                 if (ret) {
10538                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10539                         btrfs_dec_block_group_ro(root, block_group);
10540                         goto end_trans;
10541                 }
10542                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10543
10544                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10545                 spin_lock(&space_info->lock);
10546                 spin_lock(&block_group->lock);
10547
10548                 space_info->bytes_pinned -= block_group->pinned;
10549                 space_info->bytes_readonly += block_group->pinned;
10550                 percpu_counter_add(&space_info->total_bytes_pinned,
10551                                    -block_group->pinned);
10552                 block_group->pinned = 0;
10553
10554                 spin_unlock(&block_group->lock);
10555                 spin_unlock(&space_info->lock);
10556
10557                 /* DISCARD can flip during remount */
10558                 trimming = btrfs_test_opt(root, DISCARD);
10559
10560                 /* Implicit trim during transaction commit. */
10561                 if (trimming)
10562                         btrfs_get_block_group_trimming(block_group);
10563
10564                 /*
10565                  * Btrfs_remove_chunk will abort the transaction if things go
10566                  * horribly wrong.
10567                  */
10568                 ret = btrfs_remove_chunk(trans, root,
10569                                          block_group->key.objectid);
10570
10571                 if (ret) {
10572                         if (trimming)
10573                                 btrfs_put_block_group_trimming(block_group);
10574                         goto end_trans;
10575                 }
10576
10577                 /*
10578                  * If we're not mounted with -odiscard, we can just forget
10579                  * about this block group. Otherwise we'll need to wait
10580                  * until transaction commit to do the actual discard.
10581                  */
10582                 if (trimming) {
10583                         spin_lock(&fs_info->unused_bgs_lock);
10584                         /*
10585                          * A concurrent scrub might have added us to the list
10586                          * fs_info->unused_bgs, so use a list_move operation
10587                          * to add the block group to the deleted_bgs list.
10588                          */
10589                         list_move(&block_group->bg_list,
10590                                   &trans->transaction->deleted_bgs);
10591                         spin_unlock(&fs_info->unused_bgs_lock);
10592                         btrfs_get_block_group(block_group);
10593                 }
10594 end_trans:
10595                 btrfs_end_transaction(trans, root);
10596 next:
10597                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10598                 btrfs_put_block_group(block_group);
10599                 spin_lock(&fs_info->unused_bgs_lock);
10600         }
10601         spin_unlock(&fs_info->unused_bgs_lock);
10602 }
10603
10604 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10605 {
10606         struct btrfs_space_info *space_info;
10607         struct btrfs_super_block *disk_super;
10608         u64 features;
10609         u64 flags;
10610         int mixed = 0;
10611         int ret;
10612
10613         disk_super = fs_info->super_copy;
10614         if (!btrfs_super_root(disk_super))
10615                 return -EINVAL;
10616
10617         features = btrfs_super_incompat_flags(disk_super);
10618         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10619                 mixed = 1;
10620
10621         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10622         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10623         if (ret)
10624                 goto out;
10625
10626         if (mixed) {
10627                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10628                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10629         } else {
10630                 flags = BTRFS_BLOCK_GROUP_METADATA;
10631                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10632                 if (ret)
10633                         goto out;
10634
10635                 flags = BTRFS_BLOCK_GROUP_DATA;
10636                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10637         }
10638 out:
10639         return ret;
10640 }
10641
10642 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10643 {
10644         return unpin_extent_range(root, start, end, false);
10645 }
10646
10647 /*
10648  * It used to be that old block groups would be left around forever.
10649  * Iterating over them would be enough to trim unused space.  Since we
10650  * now automatically remove them, we also need to iterate over unallocated
10651  * space.
10652  *
10653  * We don't want a transaction for this since the discard may take a
10654  * substantial amount of time.  We don't require that a transaction be
10655  * running, but we do need to take a running transaction into account
10656  * to ensure that we're not discarding chunks that were released in
10657  * the current transaction.
10658  *
10659  * Holding the chunks lock will prevent other threads from allocating
10660  * or releasing chunks, but it won't prevent a running transaction
10661  * from committing and releasing the memory that the pending chunks
10662  * list head uses.  For that, we need to take a reference to the
10663  * transaction.
10664  */
10665 static int btrfs_trim_free_extents(struct btrfs_device *device,
10666                                    u64 minlen, u64 *trimmed)
10667 {
10668         u64 start = 0, len = 0;
10669         int ret;
10670
10671         *trimmed = 0;
10672
10673         /* Not writeable = nothing to do. */
10674         if (!device->writeable)
10675                 return 0;
10676
10677         /* No free space = nothing to do. */
10678         if (device->total_bytes <= device->bytes_used)
10679                 return 0;
10680
10681         ret = 0;
10682
10683         while (1) {
10684                 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
10685                 struct btrfs_transaction *trans;
10686                 u64 bytes;
10687
10688                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10689                 if (ret)
10690                         return ret;
10691
10692                 down_read(&fs_info->commit_root_sem);
10693
10694                 spin_lock(&fs_info->trans_lock);
10695                 trans = fs_info->running_transaction;
10696                 if (trans)
10697                         atomic_inc(&trans->use_count);
10698                 spin_unlock(&fs_info->trans_lock);
10699
10700                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10701                                                  &start, &len);
10702                 if (trans)
10703                         btrfs_put_transaction(trans);
10704
10705                 if (ret) {
10706                         up_read(&fs_info->commit_root_sem);
10707                         mutex_unlock(&fs_info->chunk_mutex);
10708                         if (ret == -ENOSPC)
10709                                 ret = 0;
10710                         break;
10711                 }
10712
10713                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10714                 up_read(&fs_info->commit_root_sem);
10715                 mutex_unlock(&fs_info->chunk_mutex);
10716
10717                 if (ret)
10718                         break;
10719
10720                 start += len;
10721                 *trimmed += bytes;
10722
10723                 if (fatal_signal_pending(current)) {
10724                         ret = -ERESTARTSYS;
10725                         break;
10726                 }
10727
10728                 cond_resched();
10729         }
10730
10731         return ret;
10732 }
10733
10734 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
10735 {
10736         struct btrfs_fs_info *fs_info = root->fs_info;
10737         struct btrfs_block_group_cache *cache = NULL;
10738         struct btrfs_device *device;
10739         struct list_head *devices;
10740         u64 group_trimmed;
10741         u64 start;
10742         u64 end;
10743         u64 trimmed = 0;
10744         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10745         int ret = 0;
10746
10747         /*
10748          * try to trim all FS space, our block group may start from non-zero.
10749          */
10750         if (range->len == total_bytes)
10751                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10752         else
10753                 cache = btrfs_lookup_block_group(fs_info, range->start);
10754
10755         while (cache) {
10756                 if (cache->key.objectid >= (range->start + range->len)) {
10757                         btrfs_put_block_group(cache);
10758                         break;
10759                 }
10760
10761                 start = max(range->start, cache->key.objectid);
10762                 end = min(range->start + range->len,
10763                                 cache->key.objectid + cache->key.offset);
10764
10765                 if (end - start >= range->minlen) {
10766                         if (!block_group_cache_done(cache)) {
10767                                 ret = cache_block_group(cache, 0);
10768                                 if (ret) {
10769                                         btrfs_put_block_group(cache);
10770                                         break;
10771                                 }
10772                                 ret = wait_block_group_cache_done(cache);
10773                                 if (ret) {
10774                                         btrfs_put_block_group(cache);
10775                                         break;
10776                                 }
10777                         }
10778                         ret = btrfs_trim_block_group(cache,
10779                                                      &group_trimmed,
10780                                                      start,
10781                                                      end,
10782                                                      range->minlen);
10783
10784                         trimmed += group_trimmed;
10785                         if (ret) {
10786                                 btrfs_put_block_group(cache);
10787                                 break;
10788                         }
10789                 }
10790
10791                 cache = next_block_group(fs_info->tree_root, cache);
10792         }
10793
10794         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
10795         devices = &root->fs_info->fs_devices->alloc_list;
10796         list_for_each_entry(device, devices, dev_alloc_list) {
10797                 ret = btrfs_trim_free_extents(device, range->minlen,
10798                                               &group_trimmed);
10799                 if (ret)
10800                         break;
10801
10802                 trimmed += group_trimmed;
10803         }
10804         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
10805
10806         range->len = trimmed;
10807         return ret;
10808 }
10809
10810 /*
10811  * btrfs_{start,end}_write_no_snapshoting() are similar to
10812  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10813  * data into the page cache through nocow before the subvolume is snapshoted,
10814  * but flush the data into disk after the snapshot creation, or to prevent
10815  * operations while snapshoting is ongoing and that cause the snapshot to be
10816  * inconsistent (writes followed by expanding truncates for example).
10817  */
10818 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
10819 {
10820         percpu_counter_dec(&root->subv_writers->counter);
10821         /*
10822          * Make sure counter is updated before we wake up waiters.
10823          */
10824         smp_mb();
10825         if (waitqueue_active(&root->subv_writers->wait))
10826                 wake_up(&root->subv_writers->wait);
10827 }
10828
10829 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
10830 {
10831         if (atomic_read(&root->will_be_snapshoted))
10832                 return 0;
10833
10834         percpu_counter_inc(&root->subv_writers->counter);
10835         /*
10836          * Make sure counter is updated before we check for snapshot creation.
10837          */
10838         smp_mb();
10839         if (atomic_read(&root->will_be_snapshoted)) {
10840                 btrfs_end_write_no_snapshoting(root);
10841                 return 0;
10842         }
10843         return 1;
10844 }
10845
10846 static int wait_snapshoting_atomic_t(atomic_t *a)
10847 {
10848         schedule();
10849         return 0;
10850 }
10851
10852 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
10853 {
10854         while (true) {
10855                 int ret;
10856
10857                 ret = btrfs_start_write_no_snapshoting(root);
10858                 if (ret)
10859                         break;
10860                 wait_on_atomic_t(&root->will_be_snapshoted,
10861                                  wait_snapshoting_atomic_t,
10862                                  TASK_UNINTERRUPTIBLE);
10863         }
10864 }