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 "compat.h"
  29 #include "hash.h"
  30 #include "ctree.h"
  31 #include "disk-io.h"
  32 #include "print-tree.h"
  33 #include "transaction.h"
  34 #include "volumes.h"
  35 #include "raid56.h"
  36 #include "locking.h"
  37 #include "free-space-cache.h"
  38 #include "math.h"
  39
  40 #undef SCRAMBLE_DELAYED_REFS
  41
  42 /*
  43  * control flags for do_chunk_alloc's force field
  44  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  45  * if we really need one.
  46  *
  47  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  48  * if we have very few chunks already allocated.  This is
  49  * used as part of the clustering code to help make sure
  50  * we have a good pool of storage to cluster in, without
  51  * filling the FS with empty chunks
  52  *
  53  * CHUNK_ALLOC_FORCE means it must try to allocate one
  54  *
  55  */
  56 enum {
  57         CHUNK_ALLOC_NO_FORCE = 0,
  58         CHUNK_ALLOC_LIMITED = 1,
  59         CHUNK_ALLOC_FORCE = 2,
  60 };
  61
  62 /*
  63  * Control how reservations are dealt with.
  64  *
  65  * RESERVE_FREE - freeing a reservation.
  66  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  67  *   ENOSPC accounting
  68  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  69  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  70  */
  71 enum {
  72         RESERVE_FREE = 0,
  73         RESERVE_ALLOC = 1,
  74         RESERVE_ALLOC_NO_ACCOUNT = 2,
  75 };
  76
  77 static int update_block_group(struct btrfs_root *root,
  78                               u64 bytenr, u64 num_bytes, int alloc);
  79 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  80                                 struct btrfs_root *root,
  81                                 u64 bytenr, u64 num_bytes, u64 parent,
  82                                 u64 root_objectid, u64 owner_objectid,
  83                                 u64 owner_offset, int refs_to_drop,
  84                                 struct btrfs_delayed_extent_op *extra_op);
  85 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  86                                     struct extent_buffer *leaf,
  87                                     struct btrfs_extent_item *ei);
  88 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  89                                       struct btrfs_root *root,
  90                                       u64 parent, u64 root_objectid,
  91                                       u64 flags, u64 owner, u64 offset,
  92                                       struct btrfs_key *ins, int ref_mod);
  93 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  94                                      struct btrfs_root *root,
  95                                      u64 parent, u64 root_objectid,
  96                                      u64 flags, struct btrfs_disk_key *key,
  97                                      int level, struct btrfs_key *ins);
  98 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  99                           struct btrfs_root *extent_root, u64 flags,
 100                           int force);
 101 static int find_next_key(struct btrfs_path *path, int level,
 102                          struct btrfs_key *key);
 103 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 104                             int dump_block_groups);
 105 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 106                                        u64 num_bytes, int reserve);
 107 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 108                                u64 num_bytes);
 109 int btrfs_pin_extent(struct btrfs_root *root,
 110                      u64 bytenr, u64 num_bytes, int reserved);
 111
 112 static noinline int
 113 block_group_cache_done(struct btrfs_block_group_cache *cache)
 114 {
 115         smp_mb();
 116         return cache->cached == BTRFS_CACHE_FINISHED ||
 117                 cache->cached == BTRFS_CACHE_ERROR;
 118 }
 119
 120 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 121 {
 122         return (cache->flags & bits) == bits;
 123 }
 124
 125 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 126 {
 127         atomic_inc(&cache->count);
 128 }
 129
 130 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 131 {
 132         if (atomic_dec_and_test(&cache->count)) {
 133                 WARN_ON(cache->pinned > 0);
 134                 WARN_ON(cache->reserved > 0);
 135                 kfree(cache->free_space_ctl);
 136                 kfree(cache);
 137         }
 138 }
 139
 140 /*
 141  * this adds the block group to the fs_info rb tree for the block group
 142  * cache
 143  */
 144 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 145                                 struct btrfs_block_group_cache *block_group)
 146 {
 147         struct rb_node **p;
 148         struct rb_node *parent = NULL;
 149         struct btrfs_block_group_cache *cache;
 150
 151         spin_lock(&info->block_group_cache_lock);
 152         p = &info->block_group_cache_tree.rb_node;
 153
 154         while (*p) {
 155                 parent = *p;
 156                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 157                                  cache_node);
 158                 if (block_group->key.objectid < cache->key.objectid) {
 159                         p = &(*p)->rb_left;
 160                 } else if (block_group->key.objectid > cache->key.objectid) {
 161                         p = &(*p)->rb_right;
 162                 } else {
 163                         spin_unlock(&info->block_group_cache_lock);
 164                         return -EEXIST;
 165                 }
 166         }
 167
 168         rb_link_node(&block_group->cache_node, parent, p);
 169         rb_insert_color(&block_group->cache_node,
 170                         &info->block_group_cache_tree);
 171
 172         if (info->first_logical_byte > block_group->key.objectid)
 173                 info->first_logical_byte = block_group->key.objectid;
 174
 175         spin_unlock(&info->block_group_cache_lock);
 176
 177         return 0;
 178 }
 179
 180 /*
 181  * This will return the block group at or after bytenr if contains is 0, else
 182  * it will return the block group that contains the bytenr
 183  */
 184 static struct btrfs_block_group_cache *
 185 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 186                               int contains)
 187 {
 188         struct btrfs_block_group_cache *cache, *ret = NULL;
 189         struct rb_node *n;
 190         u64 end, start;
 191
 192         spin_lock(&info->block_group_cache_lock);
 193         n = info->block_group_cache_tree.rb_node;
 194
 195         while (n) {
 196                 cache = rb_entry(n, struct btrfs_block_group_cache,
 197                                  cache_node);
 198                 end = cache->key.objectid + cache->key.offset - 1;
 199                 start = cache->key.objectid;
 200
 201                 if (bytenr < start) {
 202                         if (!contains && (!ret || start < ret->key.objectid))
 203                                 ret = cache;
 204                         n = n->rb_left;
 205                 } else if (bytenr > start) {
 206                         if (contains && bytenr <= end) {
 207                                 ret = cache;
 208                                 break;
 209                         }
 210                         n = n->rb_right;
 211                 } else {
 212                         ret = cache;
 213                         break;
 214                 }
 215         }
 216         if (ret) {
 217                 btrfs_get_block_group(ret);
 218                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 219                         info->first_logical_byte = ret->key.objectid;
 220         }
 221         spin_unlock(&info->block_group_cache_lock);
 222
 223         return ret;
 224 }
 225
 226 static int add_excluded_extent(struct btrfs_root *root,
 227                                u64 start, u64 num_bytes)
 228 {
 229         u64 end = start + num_bytes - 1;
 230         set_extent_bits(&root->fs_info->freed_extents[0],
 231                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 232         set_extent_bits(&root->fs_info->freed_extents[1],
 233                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 234         return 0;
 235 }
 236
 237 static void free_excluded_extents(struct btrfs_root *root,
 238                                   struct btrfs_block_group_cache *cache)
 239 {
 240         u64 start, end;
 241
 242         start = cache->key.objectid;
 243         end = start + cache->key.offset - 1;
 244
 245         clear_extent_bits(&root->fs_info->freed_extents[0],
 246                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 247         clear_extent_bits(&root->fs_info->freed_extents[1],
 248                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 249 }
 250
 251 static int exclude_super_stripes(struct btrfs_root *root,
 252                                  struct btrfs_block_group_cache *cache)
 253 {
 254         u64 bytenr;
 255         u64 *logical;
 256         int stripe_len;
 257         int i, nr, ret;
 258
 259         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 260                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 261                 cache->bytes_super += stripe_len;
 262                 ret = add_excluded_extent(root, cache->key.objectid,
 263                                           stripe_len);
 264                 if (ret)
 265                         return ret;
 266         }
 267
 268         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 269                 bytenr = btrfs_sb_offset(i);
 270                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 271                                        cache->key.objectid, bytenr,
 272                                        0, &logical, &nr, &stripe_len);
 273                 if (ret)
 274                         return ret;
 275
 276                 while (nr--) {
 277                         u64 start, len;
 278
 279                         if (logical[nr] > cache->key.objectid +
 280                             cache->key.offset)
 281                                 continue;
 282
 283                         if (logical[nr] + stripe_len <= cache->key.objectid)
 284                                 continue;
 285
 286                         start = logical[nr];
 287                         if (start < cache->key.objectid) {
 288                                 start = cache->key.objectid;
 289                                 len = (logical[nr] + stripe_len) - start;
 290                         } else {
 291                                 len = min_t(u64, stripe_len,
 292                                             cache->key.objectid +
 293                                             cache->key.offset - start);
 294                         }
 295
 296                         cache->bytes_super += len;
 297                         ret = add_excluded_extent(root, start, len);
 298                         if (ret) {
 299                                 kfree(logical);
 300                                 return ret;
 301                         }
 302                 }
 303
 304                 kfree(logical);
 305         }
 306         return 0;
 307 }
 308
 309 static struct btrfs_caching_control *
 310 get_caching_control(struct btrfs_block_group_cache *cache)
 311 {
 312         struct btrfs_caching_control *ctl;
 313
 314         spin_lock(&cache->lock);
 315         if (cache->cached != BTRFS_CACHE_STARTED) {
 316                 spin_unlock(&cache->lock);
 317                 return NULL;
 318         }
 319
 320         /* We're loading it the fast way, so we don't have a caching_ctl. */
 321         if (!cache->caching_ctl) {
 322                 spin_unlock(&cache->lock);
 323                 return NULL;
 324         }
 325
 326         ctl = cache->caching_ctl;
 327         atomic_inc(&ctl->count);
 328         spin_unlock(&cache->lock);
 329         return ctl;
 330 }
 331
 332 static void put_caching_control(struct btrfs_caching_control *ctl)
 333 {
 334         if (atomic_dec_and_test(&ctl->count))
 335                 kfree(ctl);
 336 }
 337
 338 /*
 339  * this is only called by cache_block_group, since we could have freed extents
 340  * we need to check the pinned_extents for any extents that can't be used yet
 341  * since their free space will be released as soon as the transaction commits.
 342  */
 343 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 344                               struct btrfs_fs_info *info, u64 start, u64 end)
 345 {
 346         u64 extent_start, extent_end, size, total_added = 0;
 347         int ret;
 348
 349         while (start < end) {
 350                 ret = find_first_extent_bit(info->pinned_extents, start,
 351                                             &extent_start, &extent_end,
 352                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 353                                             NULL);
 354                 if (ret)
 355                         break;
 356
 357                 if (extent_start <= start) {
 358                         start = extent_end + 1;
 359                 } else if (extent_start > start && extent_start < end) {
 360                         size = extent_start - start;
 361                         total_added += size;
 362                         ret = btrfs_add_free_space(block_group, start,
 363                                                    size);
 364                         BUG_ON(ret); /* -ENOMEM or logic error */
 365                         start = extent_end + 1;
 366                 } else {
 367                         break;
 368                 }
 369         }
 370
 371         if (start < end) {
 372                 size = end - start;
 373                 total_added += size;
 374                 ret = btrfs_add_free_space(block_group, start, size);
 375                 BUG_ON(ret); /* -ENOMEM or logic error */
 376         }
 377
 378         return total_added;
 379 }
 380
 381 static noinline void caching_thread(struct btrfs_work *work)
 382 {
 383         struct btrfs_block_group_cache *block_group;
 384         struct btrfs_fs_info *fs_info;
 385         struct btrfs_caching_control *caching_ctl;
 386         struct btrfs_root *extent_root;
 387         struct btrfs_path *path;
 388         struct extent_buffer *leaf;
 389         struct btrfs_key key;
 390         u64 total_found = 0;
 391         u64 last = 0;
 392         u32 nritems;
 393         int ret = -ENOMEM;
 394
 395         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 396         block_group = caching_ctl->block_group;
 397         fs_info = block_group->fs_info;
 398         extent_root = fs_info->extent_root;
 399
 400         path = btrfs_alloc_path();
 401         if (!path)
 402                 goto out;
 403
 404         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 405
 406         /*
 407          * We don't want to deadlock with somebody trying to allocate a new
 408          * extent for the extent root while also trying to search the extent
 409          * root to add free space.  So we skip locking and search the commit
 410          * root, since its read-only
 411          */
 412         path->skip_locking = 1;
 413         path->search_commit_root = 1;
 414         path->reada = 1;
 415
 416         key.objectid = last;
 417         key.offset = 0;
 418         key.type = BTRFS_EXTENT_ITEM_KEY;
 419 again:
 420         mutex_lock(&caching_ctl->mutex);
 421         /* need to make sure the commit_root doesn't disappear */
 422         down_read(&fs_info->extent_commit_sem);
 423
 424 next:
 425         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 426         if (ret < 0)
 427                 goto err;
 428
 429         leaf = path->nodes[0];
 430         nritems = btrfs_header_nritems(leaf);
 431
 432         while (1) {
 433                 if (btrfs_fs_closing(fs_info) > 1) {
 434                         last = (u64)-1;
 435                         break;
 436                 }
 437
 438                 if (path->slots[0] < nritems) {
 439                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 440                 } else {
 441                         ret = find_next_key(path, 0, &key);
 442                         if (ret)
 443                                 break;
 444
 445                         if (need_resched()) {
 446                                 caching_ctl->progress = last;
 447                                 btrfs_release_path(path);
 448                                 up_read(&fs_info->extent_commit_sem);
 449                                 mutex_unlock(&caching_ctl->mutex);
 450                                 cond_resched();
 451                                 goto again;
 452                         }
 453
 454                         ret = btrfs_next_leaf(extent_root, path);
 455                         if (ret < 0)
 456                                 goto err;
 457                         if (ret)
 458                                 break;
 459                         leaf = path->nodes[0];
 460                         nritems = btrfs_header_nritems(leaf);
 461                         continue;
 462                 }
 463
 464                 if (key.objectid < last) {
 465                         key.objectid = last;
 466                         key.offset = 0;
 467                         key.type = BTRFS_EXTENT_ITEM_KEY;
 468
 469                         caching_ctl->progress = last;
 470                         btrfs_release_path(path);
 471                         goto next;
 472                 }
 473
 474                 if (key.objectid < block_group->key.objectid) {
 475                         path->slots[0]++;
 476                         continue;
 477                 }
 478
 479                 if (key.objectid >= block_group->key.objectid +
 480                     block_group->key.offset)
 481                         break;
 482
 483                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 484                     key.type == BTRFS_METADATA_ITEM_KEY) {
 485                         total_found += add_new_free_space(block_group,
 486                                                           fs_info, last,
 487                                                           key.objectid);
 488                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 489                                 last = key.objectid +
 490                                         fs_info->tree_root->leafsize;
 491                         else
 492                                 last = key.objectid + key.offset;
 493
 494                         if (total_found > (1024 * 1024 * 2)) {
 495                                 total_found = 0;
 496                                 wake_up(&caching_ctl->wait);
 497                         }
 498                 }
 499                 path->slots[0]++;
 500         }
 501         ret = 0;
 502
 503         total_found += add_new_free_space(block_group, fs_info, last,
 504                                           block_group->key.objectid +
 505                                           block_group->key.offset);
 506         caching_ctl->progress = (u64)-1;
 507
 508         spin_lock(&block_group->lock);
 509         block_group->caching_ctl = NULL;
 510         block_group->cached = BTRFS_CACHE_FINISHED;
 511         spin_unlock(&block_group->lock);
 512
 513 err:
 514         btrfs_free_path(path);
 515         up_read(&fs_info->extent_commit_sem);
 516
 517         free_excluded_extents(extent_root, block_group);
 518
 519         mutex_unlock(&caching_ctl->mutex);
 520 out:
 521         if (ret) {
 522                 spin_lock(&block_group->lock);
 523                 block_group->caching_ctl = NULL;
 524                 block_group->cached = BTRFS_CACHE_ERROR;
 525                 spin_unlock(&block_group->lock);
 526         }
 527         wake_up(&caching_ctl->wait);
 528
 529         put_caching_control(caching_ctl);
 530         btrfs_put_block_group(block_group);
 531 }
 532
 533 static int cache_block_group(struct btrfs_block_group_cache *cache,
 534                              int load_cache_only)
 535 {
 536         DEFINE_WAIT(wait);
 537         struct btrfs_fs_info *fs_info = cache->fs_info;
 538         struct btrfs_caching_control *caching_ctl;
 539         int ret = 0;
 540
 541         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 542         if (!caching_ctl)
 543                 return -ENOMEM;
 544
 545         INIT_LIST_HEAD(&caching_ctl->list);
 546         mutex_init(&caching_ctl->mutex);
 547         init_waitqueue_head(&caching_ctl->wait);
 548         caching_ctl->block_group = cache;
 549         caching_ctl->progress = cache->key.objectid;
 550         atomic_set(&caching_ctl->count, 1);
 551         caching_ctl->work.func = caching_thread;
 552
 553         spin_lock(&cache->lock);
 554         /*
 555          * This should be a rare occasion, but this could happen I think in the
 556          * case where one thread starts to load the space cache info, and then
 557          * some other thread starts a transaction commit which tries to do an
 558          * allocation while the other thread is still loading the space cache
 559          * info.  The previous loop should have kept us from choosing this block
 560          * group, but if we've moved to the state where we will wait on caching
 561          * block groups we need to first check if we're doing a fast load here,
 562          * so we can wait for it to finish, otherwise we could end up allocating
 563          * from a block group who's cache gets evicted for one reason or
 564          * another.
 565          */
 566         while (cache->cached == BTRFS_CACHE_FAST) {
 567                 struct btrfs_caching_control *ctl;
 568
 569                 ctl = cache->caching_ctl;
 570                 atomic_inc(&ctl->count);
 571                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 572                 spin_unlock(&cache->lock);
 573
 574                 schedule();
 575
 576                 finish_wait(&ctl->wait, &wait);
 577                 put_caching_control(ctl);
 578                 spin_lock(&cache->lock);
 579         }
 580
 581         if (cache->cached != BTRFS_CACHE_NO) {
 582                 spin_unlock(&cache->lock);
 583                 kfree(caching_ctl);
 584                 return 0;
 585         }
 586         WARN_ON(cache->caching_ctl);
 587         cache->caching_ctl = caching_ctl;
 588         cache->cached = BTRFS_CACHE_FAST;
 589         spin_unlock(&cache->lock);
 590
 591         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 592                 ret = load_free_space_cache(fs_info, cache);
 593
 594                 spin_lock(&cache->lock);
 595                 if (ret == 1) {
 596                         cache->caching_ctl = NULL;
 597                         cache->cached = BTRFS_CACHE_FINISHED;
 598                         cache->last_byte_to_unpin = (u64)-1;
 599                 } else {
 600                         if (load_cache_only) {
 601                                 cache->caching_ctl = NULL;
 602                                 cache->cached = BTRFS_CACHE_NO;
 603                         } else {
 604                                 cache->cached = BTRFS_CACHE_STARTED;
 605                         }
 606                 }
 607                 spin_unlock(&cache->lock);
 608                 wake_up(&caching_ctl->wait);
 609                 if (ret == 1) {
 610                         put_caching_control(caching_ctl);
 611                         free_excluded_extents(fs_info->extent_root, cache);
 612                         return 0;
 613                 }
 614         } else {
 615                 /*
 616                  * We are not going to do the fast caching, set cached to the
 617                  * appropriate value and wakeup any waiters.
 618                  */
 619                 spin_lock(&cache->lock);
 620                 if (load_cache_only) {
 621                         cache->caching_ctl = NULL;
 622                         cache->cached = BTRFS_CACHE_NO;
 623                 } else {
 624                         cache->cached = BTRFS_CACHE_STARTED;
 625                 }
 626                 spin_unlock(&cache->lock);
 627                 wake_up(&caching_ctl->wait);
 628         }
 629
 630         if (load_cache_only) {
 631                 put_caching_control(caching_ctl);
 632                 return 0;
 633         }
 634
 635         down_write(&fs_info->extent_commit_sem);
 636         atomic_inc(&caching_ctl->count);
 637         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 638         up_write(&fs_info->extent_commit_sem);
 639
 640         btrfs_get_block_group(cache);
 641
 642         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 643
 644         return ret;
 645 }
 646
 647 /*
 648  * return the block group that starts at or after bytenr
 649  */
 650 static struct btrfs_block_group_cache *
 651 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 652 {
 653         struct btrfs_block_group_cache *cache;
 654
 655         cache = block_group_cache_tree_search(info, bytenr, 0);
 656
 657         return cache;
 658 }
 659
 660 /*
 661  * return the block group that contains the given bytenr
 662  */
 663 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 664                                                  struct btrfs_fs_info *info,
 665                                                  u64 bytenr)
 666 {
 667         struct btrfs_block_group_cache *cache;
 668
 669         cache = block_group_cache_tree_search(info, bytenr, 1);
 670
 671         return cache;
 672 }
 673
 674 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 675                                                   u64 flags)
 676 {
 677         struct list_head *head = &info->space_info;
 678         struct btrfs_space_info *found;
 679
 680         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 681
 682         rcu_read_lock();
 683         list_for_each_entry_rcu(found, head, list) {
 684                 if (found->flags & flags) {
 685                         rcu_read_unlock();
 686                         return found;
 687                 }
 688         }
 689         rcu_read_unlock();
 690         return NULL;
 691 }
 692
 693 /*
 694  * after adding space to the filesystem, we need to clear the full flags
 695  * on all the space infos.
 696  */
 697 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 698 {
 699         struct list_head *head = &info->space_info;
 700         struct btrfs_space_info *found;
 701
 702         rcu_read_lock();
 703         list_for_each_entry_rcu(found, head, list)
 704                 found->full = 0;
 705         rcu_read_unlock();
 706 }
 707
 708 /* simple helper to search for an existing extent at a given offset */
 709 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 710 {
 711         int ret;
 712         struct btrfs_key key;
 713         struct btrfs_path *path;
 714
 715         path = btrfs_alloc_path();
 716         if (!path)
 717                 return -ENOMEM;
 718
 719         key.objectid = start;
 720         key.offset = len;
 721         key.type = BTRFS_EXTENT_ITEM_KEY;
 722         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 723                                 0, 0);
 724         if (ret > 0) {
 725                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 726                 if (key.objectid == start &&
 727                     key.type == BTRFS_METADATA_ITEM_KEY)
 728                         ret = 0;
 729         }
 730         btrfs_free_path(path);
 731         return ret;
 732 }
 733
 734 /*
 735  * helper function to lookup reference count and flags of a tree block.
 736  *
 737  * the head node for delayed ref is used to store the sum of all the
 738  * reference count modifications queued up in the rbtree. the head
 739  * node may also store the extent flags to set. This way you can check
 740  * to see what the reference count and extent flags would be if all of
 741  * the delayed refs are not processed.
 742  */
 743 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 744                              struct btrfs_root *root, u64 bytenr,
 745                              u64 offset, int metadata, u64 *refs, u64 *flags)
 746 {
 747         struct btrfs_delayed_ref_head *head;
 748         struct btrfs_delayed_ref_root *delayed_refs;
 749         struct btrfs_path *path;
 750         struct btrfs_extent_item *ei;
 751         struct extent_buffer *leaf;
 752         struct btrfs_key key;
 753         u32 item_size;
 754         u64 num_refs;
 755         u64 extent_flags;
 756         int ret;
 757
 758         /*
 759          * If we don't have skinny metadata, don't bother doing anything
 760          * different
 761          */
 762         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 763                 offset = root->leafsize;
 764                 metadata = 0;
 765         }
 766
 767         path = btrfs_alloc_path();
 768         if (!path)
 769                 return -ENOMEM;
 770
 771         if (metadata) {
 772                 key.objectid = bytenr;
 773                 key.type = BTRFS_METADATA_ITEM_KEY;
 774                 key.offset = offset;
 775         } else {
 776                 key.objectid = bytenr;
 777                 key.type = BTRFS_EXTENT_ITEM_KEY;
 778                 key.offset = offset;
 779         }
 780
 781         if (!trans) {
 782                 path->skip_locking = 1;
 783                 path->search_commit_root = 1;
 784         }
 785 again:
 786         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 787                                 &key, path, 0, 0);
 788         if (ret < 0)
 789                 goto out_free;
 790
 791         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 792                 metadata = 0;
 793                 if (path->slots[0]) {
 794                         path->slots[0]--;
 795                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 796                                               path->slots[0]);
 797                         if (key.objectid == bytenr &&
 798                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 799                             key.offset == root->leafsize)
 800                                 ret = 0;
 801                 }
 802                 if (ret) {
 803                         key.objectid = bytenr;
 804                         key.type = BTRFS_EXTENT_ITEM_KEY;
 805                         key.offset = root->leafsize;
 806                         btrfs_release_path(path);
 807                         goto again;
 808                 }
 809         }
 810
 811         if (ret == 0) {
 812                 leaf = path->nodes[0];
 813                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 814                 if (item_size >= sizeof(*ei)) {
 815                         ei = btrfs_item_ptr(leaf, path->slots[0],
 816                                             struct btrfs_extent_item);
 817                         num_refs = btrfs_extent_refs(leaf, ei);
 818                         extent_flags = btrfs_extent_flags(leaf, ei);
 819                 } else {
 820 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 821                         struct btrfs_extent_item_v0 *ei0;
 822                         BUG_ON(item_size != sizeof(*ei0));
 823                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 824                                              struct btrfs_extent_item_v0);
 825                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 826                         /* FIXME: this isn't correct for data */
 827                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 828 #else
 829                         BUG();
 830 #endif
 831                 }
 832                 BUG_ON(num_refs == 0);
 833         } else {
 834                 num_refs = 0;
 835                 extent_flags = 0;
 836                 ret = 0;
 837         }
 838
 839         if (!trans)
 840                 goto out;
 841
 842         delayed_refs = &trans->transaction->delayed_refs;
 843         spin_lock(&delayed_refs->lock);
 844         head = btrfs_find_delayed_ref_head(trans, bytenr);
 845         if (head) {
 846                 if (!mutex_trylock(&head->mutex)) {
 847                         atomic_inc(&head->node.refs);
 848                         spin_unlock(&delayed_refs->lock);
 849
 850                         btrfs_release_path(path);
 851
 852                         /*
 853                          * Mutex was contended, block until it's released and try
 854                          * again
 855                          */
 856                         mutex_lock(&head->mutex);
 857                         mutex_unlock(&head->mutex);
 858                         btrfs_put_delayed_ref(&head->node);
 859                         goto again;
 860                 }
 861                 if (head->extent_op && head->extent_op->update_flags)
 862                         extent_flags |= head->extent_op->flags_to_set;
 863                 else
 864                         BUG_ON(num_refs == 0);
 865
 866                 num_refs += head->node.ref_mod;
 867                 mutex_unlock(&head->mutex);
 868         }
 869         spin_unlock(&delayed_refs->lock);
 870 out:
 871         WARN_ON(num_refs == 0);
 872         if (refs)
 873                 *refs = num_refs;
 874         if (flags)
 875                 *flags = extent_flags;
 876 out_free:
 877         btrfs_free_path(path);
 878         return ret;
 879 }
 880
 881 /*
 882  * Back reference rules.  Back refs have three main goals:
 883  *
 884  * 1) differentiate between all holders of references to an extent so that
 885  *    when a reference is dropped we can make sure it was a valid reference
 886  *    before freeing the extent.
 887  *
 888  * 2) Provide enough information to quickly find the holders of an extent
 889  *    if we notice a given block is corrupted or bad.
 890  *
 891  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 892  *    maintenance.  This is actually the same as #2, but with a slightly
 893  *    different use case.
 894  *
 895  * There are two kinds of back refs. The implicit back refs is optimized
 896  * for pointers in non-shared tree blocks. For a given pointer in a block,
 897  * back refs of this kind provide information about the block's owner tree
 898  * and the pointer's key. These information allow us to find the block by
 899  * b-tree searching. The full back refs is for pointers in tree blocks not
 900  * referenced by their owner trees. The location of tree block is recorded
 901  * in the back refs. Actually the full back refs is generic, and can be
 902  * used in all cases the implicit back refs is used. The major shortcoming
 903  * of the full back refs is its overhead. Every time a tree block gets
 904  * COWed, we have to update back refs entry for all pointers in it.
 905  *
 906  * For a newly allocated tree block, we use implicit back refs for
 907  * pointers in it. This means most tree related operations only involve
 908  * implicit back refs. For a tree block created in old transaction, the
 909  * only way to drop a reference to it is COW it. So we can detect the
 910  * event that tree block loses its owner tree's reference and do the
 911  * back refs conversion.
 912  *
 913  * When a tree block is COW'd through a tree, there are four cases:
 914  *
 915  * The reference count of the block is one and the tree is the block's
 916  * owner tree. Nothing to do in this case.
 917  *
 918  * The reference count of the block is one and the tree is not the
 919  * block's owner tree. In this case, full back refs is used for pointers
 920  * in the block. Remove these full back refs, add implicit back refs for
 921  * every pointers in the new block.
 922  *
 923  * The reference count of the block is greater than one and the tree is
 924  * the block's owner tree. In this case, implicit back refs is used for
 925  * pointers in the block. Add full back refs for every pointers in the
 926  * block, increase lower level extents' reference counts. The original
 927  * implicit back refs are entailed to the new block.
 928  *
 929  * The reference count of the block is greater than one and the tree is
 930  * not the block's owner tree. Add implicit back refs for every pointer in
 931  * the new block, increase lower level extents' reference count.
 932  *
 933  * Back Reference Key composing:
 934  *
 935  * The key objectid corresponds to the first byte in the extent,
 936  * The key type is used to differentiate between types of back refs.
 937  * There are different meanings of the key offset for different types
 938  * of back refs.
 939  *
 940  * File extents can be referenced by:
 941  *
 942  * - multiple snapshots, subvolumes, or different generations in one subvol
 943  * - different files inside a single subvolume
 944  * - different offsets inside a file (bookend extents in file.c)
 945  *
 946  * The extent ref structure for the implicit back refs has fields for:
 947  *
 948  * - Objectid of the subvolume root
 949  * - objectid of the file holding the reference
 950  * - original offset in the file
 951  * - how many bookend extents
 952  *
 953  * The key offset for the implicit back refs is hash of the first
 954  * three fields.
 955  *
 956  * The extent ref structure for the full back refs has field for:
 957  *
 958  * - number of pointers in the tree leaf
 959  *
 960  * The key offset for the implicit back refs is the first byte of
 961  * the tree leaf
 962  *
 963  * When a file extent is allocated, The implicit back refs is used.
 964  * the fields are filled in:
 965  *
 966  *     (root_key.objectid, inode objectid, offset in file, 1)
 967  *
 968  * When a file extent is removed file truncation, we find the
 969  * corresponding implicit back refs and check the following fields:
 970  *
 971  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 972  *
 973  * Btree extents can be referenced by:
 974  *
 975  * - Different subvolumes
 976  *
 977  * Both the implicit back refs and the full back refs for tree blocks
 978  * only consist of key. The key offset for the implicit back refs is
 979  * objectid of block's owner tree. The key offset for the full back refs
 980  * is the first byte of parent block.
 981  *
 982  * When implicit back refs is used, information about the lowest key and
 983  * level of the tree block are required. These information are stored in
 984  * tree block info structure.
 985  */
 986
 987 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 988 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 989                                   struct btrfs_root *root,
 990                                   struct btrfs_path *path,
 991                                   u64 owner, u32 extra_size)
 992 {
 993         struct btrfs_extent_item *item;
 994         struct btrfs_extent_item_v0 *ei0;
 995         struct btrfs_extent_ref_v0 *ref0;
 996         struct btrfs_tree_block_info *bi;
 997         struct extent_buffer *leaf;
 998         struct btrfs_key key;
 999         struct btrfs_key found_key;
1000         u32 new_size = sizeof(*item);
1001         u64 refs;
1002         int ret;
1003
1004         leaf = path->nodes[0];
1005         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1006
1007         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1008         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1009                              struct btrfs_extent_item_v0);
1010         refs = btrfs_extent_refs_v0(leaf, ei0);
1011
1012         if (owner == (u64)-1) {
1013                 while (1) {
1014                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1015                                 ret = btrfs_next_leaf(root, path);
1016                                 if (ret < 0)
1017                                         return ret;
1018                                 BUG_ON(ret > 0); /* Corruption */
1019                                 leaf = path->nodes[0];
1020                         }
1021                         btrfs_item_key_to_cpu(leaf, &found_key,
1022                                               path->slots[0]);
1023                         BUG_ON(key.objectid != found_key.objectid);
1024                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1025                                 path->slots[0]++;
1026                                 continue;
1027                         }
1028                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1029                                               struct btrfs_extent_ref_v0);
1030                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1031                         break;
1032                 }
1033         }
1034         btrfs_release_path(path);
1035
1036         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1037                 new_size += sizeof(*bi);
1038
1039         new_size -= sizeof(*ei0);
1040         ret = btrfs_search_slot(trans, root, &key, path,
1041                                 new_size + extra_size, 1);
1042         if (ret < 0)
1043                 return ret;
1044         BUG_ON(ret); /* Corruption */
1045
1046         btrfs_extend_item(root, path, new_size);
1047
1048         leaf = path->nodes[0];
1049         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1050         btrfs_set_extent_refs(leaf, item, refs);
1051         /* FIXME: get real generation */
1052         btrfs_set_extent_generation(leaf, item, 0);
1053         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1054                 btrfs_set_extent_flags(leaf, item,
1055                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1056                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1057                 bi = (struct btrfs_tree_block_info *)(item + 1);
1058                 /* FIXME: get first key of the block */
1059                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1060                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1061         } else {
1062                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1063         }
1064         btrfs_mark_buffer_dirty(leaf);
1065         return 0;
1066 }
1067 #endif
1068
1069 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1070 {
1071         u32 high_crc = ~(u32)0;
1072         u32 low_crc = ~(u32)0;
1073         __le64 lenum;
1074
1075         lenum = cpu_to_le64(root_objectid);
1076         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1077         lenum = cpu_to_le64(owner);
1078         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1079         lenum = cpu_to_le64(offset);
1080         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1081
1082         return ((u64)high_crc << 31) ^ (u64)low_crc;
1083 }
1084
1085 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1086                                      struct btrfs_extent_data_ref *ref)
1087 {
1088         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1089                                     btrfs_extent_data_ref_objectid(leaf, ref),
1090                                     btrfs_extent_data_ref_offset(leaf, ref));
1091 }
1092
1093 static int match_extent_data_ref(struct extent_buffer *leaf,
1094                                  struct btrfs_extent_data_ref *ref,
1095                                  u64 root_objectid, u64 owner, u64 offset)
1096 {
1097         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1098             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1099             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1100                 return 0;
1101         return 1;
1102 }
1103
1104 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1105                                            struct btrfs_root *root,
1106                                            struct btrfs_path *path,
1107                                            u64 bytenr, u64 parent,
1108                                            u64 root_objectid,
1109                                            u64 owner, u64 offset)
1110 {
1111         struct btrfs_key key;
1112         struct btrfs_extent_data_ref *ref;
1113         struct extent_buffer *leaf;
1114         u32 nritems;
1115         int ret;
1116         int recow;
1117         int err = -ENOENT;
1118
1119         key.objectid = bytenr;
1120         if (parent) {
1121                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1122                 key.offset = parent;
1123         } else {
1124                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1125                 key.offset = hash_extent_data_ref(root_objectid,
1126                                                   owner, offset);
1127         }
1128 again:
1129         recow = 0;
1130         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1131         if (ret < 0) {
1132                 err = ret;
1133                 goto fail;
1134         }
1135
1136         if (parent) {
1137                 if (!ret)
1138                         return 0;
1139 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1140                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1141                 btrfs_release_path(path);
1142                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1143                 if (ret < 0) {
1144                         err = ret;
1145                         goto fail;
1146                 }
1147                 if (!ret)
1148                         return 0;
1149 #endif
1150                 goto fail;
1151         }
1152
1153         leaf = path->nodes[0];
1154         nritems = btrfs_header_nritems(leaf);
1155         while (1) {
1156                 if (path->slots[0] >= nritems) {
1157                         ret = btrfs_next_leaf(root, path);
1158                         if (ret < 0)
1159                                 err = ret;
1160                         if (ret)
1161                                 goto fail;
1162
1163                         leaf = path->nodes[0];
1164                         nritems = btrfs_header_nritems(leaf);
1165                         recow = 1;
1166                 }
1167
1168                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1169                 if (key.objectid != bytenr ||
1170                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1171                         goto fail;
1172
1173                 ref = btrfs_item_ptr(leaf, path->slots[0],
1174                                      struct btrfs_extent_data_ref);
1175
1176                 if (match_extent_data_ref(leaf, ref, root_objectid,
1177                                           owner, offset)) {
1178                         if (recow) {
1179                                 btrfs_release_path(path);
1180                                 goto again;
1181                         }
1182                         err = 0;
1183                         break;
1184                 }
1185                 path->slots[0]++;
1186         }
1187 fail:
1188         return err;
1189 }
1190
1191 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1192                                            struct btrfs_root *root,
1193                                            struct btrfs_path *path,
1194                                            u64 bytenr, u64 parent,
1195                                            u64 root_objectid, u64 owner,
1196                                            u64 offset, int refs_to_add)
1197 {
1198         struct btrfs_key key;
1199         struct extent_buffer *leaf;
1200         u32 size;
1201         u32 num_refs;
1202         int ret;
1203
1204         key.objectid = bytenr;
1205         if (parent) {
1206                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1207                 key.offset = parent;
1208                 size = sizeof(struct btrfs_shared_data_ref);
1209         } else {
1210                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1211                 key.offset = hash_extent_data_ref(root_objectid,
1212                                                   owner, offset);
1213                 size = sizeof(struct btrfs_extent_data_ref);
1214         }
1215
1216         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1217         if (ret && ret != -EEXIST)
1218                 goto fail;
1219
1220         leaf = path->nodes[0];
1221         if (parent) {
1222                 struct btrfs_shared_data_ref *ref;
1223                 ref = btrfs_item_ptr(leaf, path->slots[0],
1224                                      struct btrfs_shared_data_ref);
1225                 if (ret == 0) {
1226                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1227                 } else {
1228                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1229                         num_refs += refs_to_add;
1230                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1231                 }
1232         } else {
1233                 struct btrfs_extent_data_ref *ref;
1234                 while (ret == -EEXIST) {
1235                         ref = btrfs_item_ptr(leaf, path->slots[0],
1236                                              struct btrfs_extent_data_ref);
1237                         if (match_extent_data_ref(leaf, ref, root_objectid,
1238                                                   owner, offset))
1239                                 break;
1240                         btrfs_release_path(path);
1241                         key.offset++;
1242                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1243                                                       size);
1244                         if (ret && ret != -EEXIST)
1245                                 goto fail;
1246
1247                         leaf = path->nodes[0];
1248                 }
1249                 ref = btrfs_item_ptr(leaf, path->slots[0],
1250                                      struct btrfs_extent_data_ref);
1251                 if (ret == 0) {
1252                         btrfs_set_extent_data_ref_root(leaf, ref,
1253                                                        root_objectid);
1254                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1255                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1256                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1257                 } else {
1258                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1259                         num_refs += refs_to_add;
1260                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1261                 }
1262         }
1263         btrfs_mark_buffer_dirty(leaf);
1264         ret = 0;
1265 fail:
1266         btrfs_release_path(path);
1267         return ret;
1268 }
1269
1270 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1271                                            struct btrfs_root *root,
1272                                            struct btrfs_path *path,
1273                                            int refs_to_drop)
1274 {
1275         struct btrfs_key key;
1276         struct btrfs_extent_data_ref *ref1 = NULL;
1277         struct btrfs_shared_data_ref *ref2 = NULL;
1278         struct extent_buffer *leaf;
1279         u32 num_refs = 0;
1280         int ret = 0;
1281
1282         leaf = path->nodes[0];
1283         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1284
1285         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1286                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1287                                       struct btrfs_extent_data_ref);
1288                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1289         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1290                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1291                                       struct btrfs_shared_data_ref);
1292                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1293 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1294         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1295                 struct btrfs_extent_ref_v0 *ref0;
1296                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1297                                       struct btrfs_extent_ref_v0);
1298                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1299 #endif
1300         } else {
1301                 BUG();
1302         }
1303
1304         BUG_ON(num_refs < refs_to_drop);
1305         num_refs -= refs_to_drop;
1306
1307         if (num_refs == 0) {
1308                 ret = btrfs_del_item(trans, root, path);
1309         } else {
1310                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1311                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1312                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1313                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1314 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1315                 else {
1316                         struct btrfs_extent_ref_v0 *ref0;
1317                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1318                                         struct btrfs_extent_ref_v0);
1319                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1320                 }
1321 #endif
1322                 btrfs_mark_buffer_dirty(leaf);
1323         }
1324         return ret;
1325 }
1326
1327 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1328                                           struct btrfs_path *path,
1329                                           struct btrfs_extent_inline_ref *iref)
1330 {
1331         struct btrfs_key key;
1332         struct extent_buffer *leaf;
1333         struct btrfs_extent_data_ref *ref1;
1334         struct btrfs_shared_data_ref *ref2;
1335         u32 num_refs = 0;
1336
1337         leaf = path->nodes[0];
1338         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1339         if (iref) {
1340                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1341                     BTRFS_EXTENT_DATA_REF_KEY) {
1342                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1343                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1344                 } else {
1345                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1346                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1347                 }
1348         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1349                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1350                                       struct btrfs_extent_data_ref);
1351                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1352         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1353                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1354                                       struct btrfs_shared_data_ref);
1355                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1356 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1357         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1358                 struct btrfs_extent_ref_v0 *ref0;
1359                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1360                                       struct btrfs_extent_ref_v0);
1361                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1362 #endif
1363         } else {
1364                 WARN_ON(1);
1365         }
1366         return num_refs;
1367 }
1368
1369 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1370                                           struct btrfs_root *root,
1371                                           struct btrfs_path *path,
1372                                           u64 bytenr, u64 parent,
1373                                           u64 root_objectid)
1374 {
1375         struct btrfs_key key;
1376         int ret;
1377
1378         key.objectid = bytenr;
1379         if (parent) {
1380                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1381                 key.offset = parent;
1382         } else {
1383                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1384                 key.offset = root_objectid;
1385         }
1386
1387         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1388         if (ret > 0)
1389                 ret = -ENOENT;
1390 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1391         if (ret == -ENOENT && parent) {
1392                 btrfs_release_path(path);
1393                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1394                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1395                 if (ret > 0)
1396                         ret = -ENOENT;
1397         }
1398 #endif
1399         return ret;
1400 }
1401
1402 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1403                                           struct btrfs_root *root,
1404                                           struct btrfs_path *path,
1405                                           u64 bytenr, u64 parent,
1406                                           u64 root_objectid)
1407 {
1408         struct btrfs_key key;
1409         int ret;
1410
1411         key.objectid = bytenr;
1412         if (parent) {
1413                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1414                 key.offset = parent;
1415         } else {
1416                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1417                 key.offset = root_objectid;
1418         }
1419
1420         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1421         btrfs_release_path(path);
1422         return ret;
1423 }
1424
1425 static inline int extent_ref_type(u64 parent, u64 owner)
1426 {
1427         int type;
1428         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1429                 if (parent > 0)
1430                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1431                 else
1432                         type = BTRFS_TREE_BLOCK_REF_KEY;
1433         } else {
1434                 if (parent > 0)
1435                         type = BTRFS_SHARED_DATA_REF_KEY;
1436                 else
1437                         type = BTRFS_EXTENT_DATA_REF_KEY;
1438         }
1439         return type;
1440 }
1441
1442 static int find_next_key(struct btrfs_path *path, int level,
1443                          struct btrfs_key *key)
1444
1445 {
1446         for (; level < BTRFS_MAX_LEVEL; level++) {
1447                 if (!path->nodes[level])
1448                         break;
1449                 if (path->slots[level] + 1 >=
1450                     btrfs_header_nritems(path->nodes[level]))
1451                         continue;
1452                 if (level == 0)
1453                         btrfs_item_key_to_cpu(path->nodes[level], key,
1454                                               path->slots[level] + 1);
1455                 else
1456                         btrfs_node_key_to_cpu(path->nodes[level], key,
1457                                               path->slots[level] + 1);
1458                 return 0;
1459         }
1460         return 1;
1461 }
1462
1463 /*
1464  * look for inline back ref. if back ref is found, *ref_ret is set
1465  * to the address of inline back ref, and 0 is returned.
1466  *
1467  * if back ref isn't found, *ref_ret is set to the address where it
1468  * should be inserted, and -ENOENT is returned.
1469  *
1470  * if insert is true and there are too many inline back refs, the path
1471  * points to the extent item, and -EAGAIN is returned.
1472  *
1473  * NOTE: inline back refs are ordered in the same way that back ref
1474  *       items in the tree are ordered.
1475  */
1476 static noinline_for_stack
1477 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1478                                  struct btrfs_root *root,
1479                                  struct btrfs_path *path,
1480                                  struct btrfs_extent_inline_ref **ref_ret,
1481                                  u64 bytenr, u64 num_bytes,
1482                                  u64 parent, u64 root_objectid,
1483                                  u64 owner, u64 offset, int insert)
1484 {
1485         struct btrfs_key key;
1486         struct extent_buffer *leaf;
1487         struct btrfs_extent_item *ei;
1488         struct btrfs_extent_inline_ref *iref;
1489         u64 flags;
1490         u64 item_size;
1491         unsigned long ptr;
1492         unsigned long end;
1493         int extra_size;
1494         int type;
1495         int want;
1496         int ret;
1497         int err = 0;
1498         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1499                                                  SKINNY_METADATA);
1500
1501         key.objectid = bytenr;
1502         key.type = BTRFS_EXTENT_ITEM_KEY;
1503         key.offset = num_bytes;
1504
1505         want = extent_ref_type(parent, owner);
1506         if (insert) {
1507                 extra_size = btrfs_extent_inline_ref_size(want);
1508                 path->keep_locks = 1;
1509         } else
1510                 extra_size = -1;
1511
1512         /*
1513          * Owner is our parent level, so we can just add one to get the level
1514          * for the block we are interested in.
1515          */
1516         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1517                 key.type = BTRFS_METADATA_ITEM_KEY;
1518                 key.offset = owner;
1519         }
1520
1521 again:
1522         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1523         if (ret < 0) {
1524                 err = ret;
1525                 goto out;
1526         }
1527
1528         /*
1529          * We may be a newly converted file system which still has the old fat
1530          * extent entries for metadata, so try and see if we have one of those.
1531          */
1532         if (ret > 0 && skinny_metadata) {
1533                 skinny_metadata = false;
1534                 if (path->slots[0]) {
1535                         path->slots[0]--;
1536                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1537                                               path->slots[0]);
1538                         if (key.objectid == bytenr &&
1539                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1540                             key.offset == num_bytes)
1541                                 ret = 0;
1542                 }
1543                 if (ret) {
1544                         key.type = BTRFS_EXTENT_ITEM_KEY;
1545                         key.offset = num_bytes;
1546                         btrfs_release_path(path);
1547                         goto again;
1548                 }
1549         }
1550
1551         if (ret && !insert) {
1552                 err = -ENOENT;
1553                 goto out;
1554         } else if (ret) {
1555                 err = -EIO;
1556                 WARN_ON(1);
1557                 goto out;
1558         }
1559
1560         leaf = path->nodes[0];
1561         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1562 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1563         if (item_size < sizeof(*ei)) {
1564                 if (!insert) {
1565                         err = -ENOENT;
1566                         goto out;
1567                 }
1568                 ret = convert_extent_item_v0(trans, root, path, owner,
1569                                              extra_size);
1570                 if (ret < 0) {
1571                         err = ret;
1572                         goto out;
1573                 }
1574                 leaf = path->nodes[0];
1575                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1576         }
1577 #endif
1578         BUG_ON(item_size < sizeof(*ei));
1579
1580         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1581         flags = btrfs_extent_flags(leaf, ei);
1582
1583         ptr = (unsigned long)(ei + 1);
1584         end = (unsigned long)ei + item_size;
1585
1586         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1587                 ptr += sizeof(struct btrfs_tree_block_info);
1588                 BUG_ON(ptr > end);
1589         }
1590
1591         err = -ENOENT;
1592         while (1) {
1593                 if (ptr >= end) {
1594                         WARN_ON(ptr > end);
1595                         break;
1596                 }
1597                 iref = (struct btrfs_extent_inline_ref *)ptr;
1598                 type = btrfs_extent_inline_ref_type(leaf, iref);
1599                 if (want < type)
1600                         break;
1601                 if (want > type) {
1602                         ptr += btrfs_extent_inline_ref_size(type);
1603                         continue;
1604                 }
1605
1606                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1607                         struct btrfs_extent_data_ref *dref;
1608                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1609                         if (match_extent_data_ref(leaf, dref, root_objectid,
1610                                                   owner, offset)) {
1611                                 err = 0;
1612                                 break;
1613                         }
1614                         if (hash_extent_data_ref_item(leaf, dref) <
1615                             hash_extent_data_ref(root_objectid, owner, offset))
1616                                 break;
1617                 } else {
1618                         u64 ref_offset;
1619                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1620                         if (parent > 0) {
1621                                 if (parent == ref_offset) {
1622                                         err = 0;
1623                                         break;
1624                                 }
1625                                 if (ref_offset < parent)
1626                                         break;
1627                         } else {
1628                                 if (root_objectid == ref_offset) {
1629                                         err = 0;
1630                                         break;
1631                                 }
1632                                 if (ref_offset < root_objectid)
1633                                         break;
1634                         }
1635                 }
1636                 ptr += btrfs_extent_inline_ref_size(type);
1637         }
1638         if (err == -ENOENT && insert) {
1639                 if (item_size + extra_size >=
1640                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1641                         err = -EAGAIN;
1642                         goto out;
1643                 }
1644                 /*
1645                  * To add new inline back ref, we have to make sure
1646                  * there is no corresponding back ref item.
1647                  * For simplicity, we just do not add new inline back
1648                  * ref if there is any kind of item for this block
1649                  */
1650                 if (find_next_key(path, 0, &key) == 0 &&
1651                     key.objectid == bytenr &&
1652                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1653                         err = -EAGAIN;
1654                         goto out;
1655                 }
1656         }
1657         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1658 out:
1659         if (insert) {
1660                 path->keep_locks = 0;
1661                 btrfs_unlock_up_safe(path, 1);
1662         }
1663         return err;
1664 }
1665
1666 /*
1667  * helper to add new inline back ref
1668  */
1669 static noinline_for_stack
1670 void setup_inline_extent_backref(struct btrfs_root *root,
1671                                  struct btrfs_path *path,
1672                                  struct btrfs_extent_inline_ref *iref,
1673                                  u64 parent, u64 root_objectid,
1674                                  u64 owner, u64 offset, int refs_to_add,
1675                                  struct btrfs_delayed_extent_op *extent_op)
1676 {
1677         struct extent_buffer *leaf;
1678         struct btrfs_extent_item *ei;
1679         unsigned long ptr;
1680         unsigned long end;
1681         unsigned long item_offset;
1682         u64 refs;
1683         int size;
1684         int type;
1685
1686         leaf = path->nodes[0];
1687         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1688         item_offset = (unsigned long)iref - (unsigned long)ei;
1689
1690         type = extent_ref_type(parent, owner);
1691         size = btrfs_extent_inline_ref_size(type);
1692
1693         btrfs_extend_item(root, path, size);
1694
1695         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1696         refs = btrfs_extent_refs(leaf, ei);
1697         refs += refs_to_add;
1698         btrfs_set_extent_refs(leaf, ei, refs);
1699         if (extent_op)
1700                 __run_delayed_extent_op(extent_op, leaf, ei);
1701
1702         ptr = (unsigned long)ei + item_offset;
1703         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1704         if (ptr < end - size)
1705                 memmove_extent_buffer(leaf, ptr + size, ptr,
1706                                       end - size - ptr);
1707
1708         iref = (struct btrfs_extent_inline_ref *)ptr;
1709         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1710         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1711                 struct btrfs_extent_data_ref *dref;
1712                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1713                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1714                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1715                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1716                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1717         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1718                 struct btrfs_shared_data_ref *sref;
1719                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1720                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1721                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1722         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1723                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1724         } else {
1725                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1726         }
1727         btrfs_mark_buffer_dirty(leaf);
1728 }
1729
1730 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1731                                  struct btrfs_root *root,
1732                                  struct btrfs_path *path,
1733                                  struct btrfs_extent_inline_ref **ref_ret,
1734                                  u64 bytenr, u64 num_bytes, u64 parent,
1735                                  u64 root_objectid, u64 owner, u64 offset)
1736 {
1737         int ret;
1738
1739         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1740                                            bytenr, num_bytes, parent,
1741                                            root_objectid, owner, offset, 0);
1742         if (ret != -ENOENT)
1743                 return ret;
1744
1745         btrfs_release_path(path);
1746         *ref_ret = NULL;
1747
1748         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1749                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1750                                             root_objectid);
1751         } else {
1752                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1753                                              root_objectid, owner, offset);
1754         }
1755         return ret;
1756 }
1757
1758 /*
1759  * helper to update/remove inline back ref
1760  */
1761 static noinline_for_stack
1762 void update_inline_extent_backref(struct btrfs_root *root,
1763                                   struct btrfs_path *path,
1764                                   struct btrfs_extent_inline_ref *iref,
1765                                   int refs_to_mod,
1766                                   struct btrfs_delayed_extent_op *extent_op)
1767 {
1768         struct extent_buffer *leaf;
1769         struct btrfs_extent_item *ei;
1770         struct btrfs_extent_data_ref *dref = NULL;
1771         struct btrfs_shared_data_ref *sref = NULL;
1772         unsigned long ptr;
1773         unsigned long end;
1774         u32 item_size;
1775         int size;
1776         int type;
1777         u64 refs;
1778
1779         leaf = path->nodes[0];
1780         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1781         refs = btrfs_extent_refs(leaf, ei);
1782         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1783         refs += refs_to_mod;
1784         btrfs_set_extent_refs(leaf, ei, refs);
1785         if (extent_op)
1786                 __run_delayed_extent_op(extent_op, leaf, ei);
1787
1788         type = btrfs_extent_inline_ref_type(leaf, iref);
1789
1790         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1791                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1792                 refs = btrfs_extent_data_ref_count(leaf, dref);
1793         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1794                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1795                 refs = btrfs_shared_data_ref_count(leaf, sref);
1796         } else {
1797                 refs = 1;
1798                 BUG_ON(refs_to_mod != -1);
1799         }
1800
1801         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1802         refs += refs_to_mod;
1803
1804         if (refs > 0) {
1805                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1806                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1807                 else
1808                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1809         } else {
1810                 size =  btrfs_extent_inline_ref_size(type);
1811                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1812                 ptr = (unsigned long)iref;
1813                 end = (unsigned long)ei + item_size;
1814                 if (ptr + size < end)
1815                         memmove_extent_buffer(leaf, ptr, ptr + size,
1816                                               end - ptr - size);
1817                 item_size -= size;
1818                 btrfs_truncate_item(root, path, item_size, 1);
1819         }
1820         btrfs_mark_buffer_dirty(leaf);
1821 }
1822
1823 static noinline_for_stack
1824 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1825                                  struct btrfs_root *root,
1826                                  struct btrfs_path *path,
1827                                  u64 bytenr, u64 num_bytes, u64 parent,
1828                                  u64 root_objectid, u64 owner,
1829                                  u64 offset, int refs_to_add,
1830                                  struct btrfs_delayed_extent_op *extent_op)
1831 {
1832         struct btrfs_extent_inline_ref *iref;
1833         int ret;
1834
1835         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1836                                            bytenr, num_bytes, parent,
1837                                            root_objectid, owner, offset, 1);
1838         if (ret == 0) {
1839                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1840                 update_inline_extent_backref(root, path, iref,
1841                                              refs_to_add, extent_op);
1842         } else if (ret == -ENOENT) {
1843                 setup_inline_extent_backref(root, path, iref, parent,
1844                                             root_objectid, owner, offset,
1845                                             refs_to_add, extent_op);
1846                 ret = 0;
1847         }
1848         return ret;
1849 }
1850
1851 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1852                                  struct btrfs_root *root,
1853                                  struct btrfs_path *path,
1854                                  u64 bytenr, u64 parent, u64 root_objectid,
1855                                  u64 owner, u64 offset, int refs_to_add)
1856 {
1857         int ret;
1858         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1859                 BUG_ON(refs_to_add != 1);
1860                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1861                                             parent, root_objectid);
1862         } else {
1863                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1864                                              parent, root_objectid,
1865                                              owner, offset, refs_to_add);
1866         }
1867         return ret;
1868 }
1869
1870 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1871                                  struct btrfs_root *root,
1872                                  struct btrfs_path *path,
1873                                  struct btrfs_extent_inline_ref *iref,
1874                                  int refs_to_drop, int is_data)
1875 {
1876         int ret = 0;
1877
1878         BUG_ON(!is_data && refs_to_drop != 1);
1879         if (iref) {
1880                 update_inline_extent_backref(root, path, iref,
1881                                              -refs_to_drop, NULL);
1882         } else if (is_data) {
1883                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1884         } else {
1885                 ret = btrfs_del_item(trans, root, path);
1886         }
1887         return ret;
1888 }
1889
1890 static int btrfs_issue_discard(struct block_device *bdev,
1891                                 u64 start, u64 len)
1892 {
1893         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1894 }
1895
1896 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1897                                 u64 num_bytes, u64 *actual_bytes)
1898 {
1899         int ret;
1900         u64 discarded_bytes = 0;
1901         struct btrfs_bio *bbio = NULL;
1902
1903
1904         /* Tell the block device(s) that the sectors can be discarded */
1905         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1906                               bytenr, &num_bytes, &bbio, 0);
1907         /* Error condition is -ENOMEM */
1908         if (!ret) {
1909                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1910                 int i;
1911
1912
1913                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1914                         if (!stripe->dev->can_discard)
1915                                 continue;
1916
1917                         ret = btrfs_issue_discard(stripe->dev->bdev,
1918                                                   stripe->physical,
1919                                                   stripe->length);
1920                         if (!ret)
1921                                 discarded_bytes += stripe->length;
1922                         else if (ret != -EOPNOTSUPP)
1923                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1924
1925                         /*
1926                          * Just in case we get back EOPNOTSUPP for some reason,
1927                          * just ignore the return value so we don't screw up
1928                          * people calling discard_extent.
1929                          */
1930                         ret = 0;
1931                 }
1932                 kfree(bbio);
1933         }
1934
1935         if (actual_bytes)
1936                 *actual_bytes = discarded_bytes;
1937
1938
1939         if (ret == -EOPNOTSUPP)
1940                 ret = 0;
1941         return ret;
1942 }
1943
1944 /* Can return -ENOMEM */
1945 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1946                          struct btrfs_root *root,
1947                          u64 bytenr, u64 num_bytes, u64 parent,
1948                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1949 {
1950         int ret;
1951         struct btrfs_fs_info *fs_info = root->fs_info;
1952
1953         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1954                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1955
1956         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1957                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1958                                         num_bytes,
1959                                         parent, root_objectid, (int)owner,
1960                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1961         } else {
1962                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1963                                         num_bytes,
1964                                         parent, root_objectid, owner, offset,
1965                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1966         }
1967         return ret;
1968 }
1969
1970 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1971                                   struct btrfs_root *root,
1972                                   u64 bytenr, u64 num_bytes,
1973                                   u64 parent, u64 root_objectid,
1974                                   u64 owner, u64 offset, int refs_to_add,
1975                                   struct btrfs_delayed_extent_op *extent_op)
1976 {
1977         struct btrfs_path *path;
1978         struct extent_buffer *leaf;
1979         struct btrfs_extent_item *item;
1980         u64 refs;
1981         int ret;
1982         int err = 0;
1983
1984         path = btrfs_alloc_path();
1985         if (!path)
1986                 return -ENOMEM;
1987
1988         path->reada = 1;
1989         path->leave_spinning = 1;
1990         /* this will setup the path even if it fails to insert the back ref */
1991         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1992                                            path, bytenr, num_bytes, parent,
1993                                            root_objectid, owner, offset,
1994                                            refs_to_add, extent_op);
1995         if (ret == 0)
1996                 goto out;
1997
1998         if (ret != -EAGAIN) {
1999                 err = ret;
2000                 goto out;
2001         }
2002
2003         leaf = path->nodes[0];
2004         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2005         refs = btrfs_extent_refs(leaf, item);
2006         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2007         if (extent_op)
2008                 __run_delayed_extent_op(extent_op, leaf, item);
2009
2010         btrfs_mark_buffer_dirty(leaf);
2011         btrfs_release_path(path);
2012
2013         path->reada = 1;
2014         path->leave_spinning = 1;
2015
2016         /* now insert the actual backref */
2017         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2018                                     path, bytenr, parent, root_objectid,
2019                                     owner, offset, refs_to_add);
2020         if (ret)
2021                 btrfs_abort_transaction(trans, root, ret);
2022 out:
2023         btrfs_free_path(path);
2024         return err;
2025 }
2026
2027 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2028                                 struct btrfs_root *root,
2029                                 struct btrfs_delayed_ref_node *node,
2030                                 struct btrfs_delayed_extent_op *extent_op,
2031                                 int insert_reserved)
2032 {
2033         int ret = 0;
2034         struct btrfs_delayed_data_ref *ref;
2035         struct btrfs_key ins;
2036         u64 parent = 0;
2037         u64 ref_root = 0;
2038         u64 flags = 0;
2039
2040         ins.objectid = node->bytenr;
2041         ins.offset = node->num_bytes;
2042         ins.type = BTRFS_EXTENT_ITEM_KEY;
2043
2044         ref = btrfs_delayed_node_to_data_ref(node);
2045         trace_run_delayed_data_ref(node, ref, node->action);
2046
2047         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2048                 parent = ref->parent;
2049         else
2050                 ref_root = ref->root;
2051
2052         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2053                 if (extent_op)
2054                         flags |= extent_op->flags_to_set;
2055                 ret = alloc_reserved_file_extent(trans, root,
2056                                                  parent, ref_root, flags,
2057                                                  ref->objectid, ref->offset,
2058                                                  &ins, node->ref_mod);
2059         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2060                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2061                                              node->num_bytes, parent,
2062                                              ref_root, ref->objectid,
2063                                              ref->offset, node->ref_mod,
2064                                              extent_op);
2065         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2066                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2067                                           node->num_bytes, parent,
2068                                           ref_root, ref->objectid,
2069                                           ref->offset, node->ref_mod,
2070                                           extent_op);
2071         } else {
2072                 BUG();
2073         }
2074         return ret;
2075 }
2076
2077 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2078                                     struct extent_buffer *leaf,
2079                                     struct btrfs_extent_item *ei)
2080 {
2081         u64 flags = btrfs_extent_flags(leaf, ei);
2082         if (extent_op->update_flags) {
2083                 flags |= extent_op->flags_to_set;
2084                 btrfs_set_extent_flags(leaf, ei, flags);
2085         }
2086
2087         if (extent_op->update_key) {
2088                 struct btrfs_tree_block_info *bi;
2089                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2090                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2091                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2092         }
2093 }
2094
2095 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2096                                  struct btrfs_root *root,
2097                                  struct btrfs_delayed_ref_node *node,
2098                                  struct btrfs_delayed_extent_op *extent_op)
2099 {
2100         struct btrfs_key key;
2101         struct btrfs_path *path;
2102         struct btrfs_extent_item *ei;
2103         struct extent_buffer *leaf;
2104         u32 item_size;
2105         int ret;
2106         int err = 0;
2107         int metadata = !extent_op->is_data;
2108
2109         if (trans->aborted)
2110                 return 0;
2111
2112         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2113                 metadata = 0;
2114
2115         path = btrfs_alloc_path();
2116         if (!path)
2117                 return -ENOMEM;
2118
2119         key.objectid = node->bytenr;
2120
2121         if (metadata) {
2122                 key.type = BTRFS_METADATA_ITEM_KEY;
2123                 key.offset = extent_op->level;
2124         } else {
2125                 key.type = BTRFS_EXTENT_ITEM_KEY;
2126                 key.offset = node->num_bytes;
2127         }
2128
2129 again:
2130         path->reada = 1;
2131         path->leave_spinning = 1;
2132         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2133                                 path, 0, 1);
2134         if (ret < 0) {
2135                 err = ret;
2136                 goto out;
2137         }
2138         if (ret > 0) {
2139                 if (metadata) {
2140                         btrfs_release_path(path);
2141                         metadata = 0;
2142
2143                         key.offset = node->num_bytes;
2144                         key.type = BTRFS_EXTENT_ITEM_KEY;
2145                         goto again;
2146                 }
2147                 err = -EIO;
2148                 goto out;
2149         }
2150
2151         leaf = path->nodes[0];
2152         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2153 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2154         if (item_size < sizeof(*ei)) {
2155                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2156                                              path, (u64)-1, 0);
2157                 if (ret < 0) {
2158                         err = ret;
2159                         goto out;
2160                 }
2161                 leaf = path->nodes[0];
2162                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2163         }
2164 #endif
2165         BUG_ON(item_size < sizeof(*ei));
2166         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2167         __run_delayed_extent_op(extent_op, leaf, ei);
2168
2169         btrfs_mark_buffer_dirty(leaf);
2170 out:
2171         btrfs_free_path(path);
2172         return err;
2173 }
2174
2175 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2176                                 struct btrfs_root *root,
2177                                 struct btrfs_delayed_ref_node *node,
2178                                 struct btrfs_delayed_extent_op *extent_op,
2179                                 int insert_reserved)
2180 {
2181         int ret = 0;
2182         struct btrfs_delayed_tree_ref *ref;
2183         struct btrfs_key ins;
2184         u64 parent = 0;
2185         u64 ref_root = 0;
2186         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2187                                                  SKINNY_METADATA);
2188
2189         ref = btrfs_delayed_node_to_tree_ref(node);
2190         trace_run_delayed_tree_ref(node, ref, node->action);
2191
2192         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2193                 parent = ref->parent;
2194         else
2195                 ref_root = ref->root;
2196
2197         ins.objectid = node->bytenr;
2198         if (skinny_metadata) {
2199                 ins.offset = ref->level;
2200                 ins.type = BTRFS_METADATA_ITEM_KEY;
2201         } else {
2202                 ins.offset = node->num_bytes;
2203                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2204         }
2205
2206         BUG_ON(node->ref_mod != 1);
2207         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2208                 BUG_ON(!extent_op || !extent_op->update_flags);
2209                 ret = alloc_reserved_tree_block(trans, root,
2210                                                 parent, ref_root,
2211                                                 extent_op->flags_to_set,
2212                                                 &extent_op->key,
2213                                                 ref->level, &ins);
2214         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2215                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2216                                              node->num_bytes, parent, ref_root,
2217                                              ref->level, 0, 1, extent_op);
2218         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2219                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2220                                           node->num_bytes, parent, ref_root,
2221                                           ref->level, 0, 1, extent_op);
2222         } else {
2223                 BUG();
2224         }
2225         return ret;
2226 }
2227
2228 /* helper function to actually process a single delayed ref entry */
2229 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2230                                struct btrfs_root *root,
2231                                struct btrfs_delayed_ref_node *node,
2232                                struct btrfs_delayed_extent_op *extent_op,
2233                                int insert_reserved)
2234 {
2235         int ret = 0;
2236
2237         if (trans->aborted)
2238                 return 0;
2239
2240         if (btrfs_delayed_ref_is_head(node)) {
2241                 struct btrfs_delayed_ref_head *head;
2242                 /*
2243                  * we've hit the end of the chain and we were supposed
2244                  * to insert this extent into the tree.  But, it got
2245                  * deleted before we ever needed to insert it, so all
2246                  * we have to do is clean up the accounting
2247                  */
2248                 BUG_ON(extent_op);
2249                 head = btrfs_delayed_node_to_head(node);
2250                 trace_run_delayed_ref_head(node, head, node->action);
2251
2252                 if (insert_reserved) {
2253                         btrfs_pin_extent(root, node->bytenr,
2254                                          node->num_bytes, 1);
2255                         if (head->is_data) {
2256                                 ret = btrfs_del_csums(trans, root,
2257                                                       node->bytenr,
2258                                                       node->num_bytes);
2259                         }
2260                 }
2261                 return ret;
2262         }
2263
2264         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2265             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2266                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2267                                            insert_reserved);
2268         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2269                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2270                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2271                                            insert_reserved);
2272         else
2273                 BUG();
2274         return ret;
2275 }
2276
2277 static noinline struct btrfs_delayed_ref_node *
2278 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2279 {
2280         struct rb_node *node;
2281         struct btrfs_delayed_ref_node *ref;
2282         int action = BTRFS_ADD_DELAYED_REF;
2283 again:
2284         /*
2285          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2286          * this prevents ref count from going down to zero when
2287          * there still are pending delayed ref.
2288          */
2289         node = rb_prev(&head->node.rb_node);
2290         while (1) {
2291                 if (!node)
2292                         break;
2293                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2294                                 rb_node);
2295                 if (ref->bytenr != head->node.bytenr)
2296                         break;
2297                 if (ref->action == action)
2298                         return ref;
2299                 node = rb_prev(node);
2300         }
2301         if (action == BTRFS_ADD_DELAYED_REF) {
2302                 action = BTRFS_DROP_DELAYED_REF;
2303                 goto again;
2304         }
2305         return NULL;
2306 }
2307
2308 /*
2309  * Returns 0 on success or if called with an already aborted transaction.
2310  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2311  */
2312 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2313                                        struct btrfs_root *root,
2314                                        struct list_head *cluster)
2315 {
2316         struct btrfs_delayed_ref_root *delayed_refs;
2317         struct btrfs_delayed_ref_node *ref;
2318         struct btrfs_delayed_ref_head *locked_ref = NULL;
2319         struct btrfs_delayed_extent_op *extent_op;
2320         struct btrfs_fs_info *fs_info = root->fs_info;
2321         int ret;
2322         int count = 0;
2323         int must_insert_reserved = 0;
2324
2325         delayed_refs = &trans->transaction->delayed_refs;
2326         while (1) {
2327                 if (!locked_ref) {
2328                         /* pick a new head ref from the cluster list */
2329                         if (list_empty(cluster))
2330                                 break;
2331
2332                         locked_ref = list_entry(cluster->next,
2333                                      struct btrfs_delayed_ref_head, cluster);
2334
2335                         /* grab the lock that says we are going to process
2336                          * all the refs for this head */
2337                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2338
2339                         /*
2340                          * we may have dropped the spin lock to get the head
2341                          * mutex lock, and that might have given someone else
2342                          * time to free the head.  If that's true, it has been
2343                          * removed from our list and we can move on.
2344                          */
2345                         if (ret == -EAGAIN) {
2346                                 locked_ref = NULL;
2347                                 count++;
2348                                 continue;
2349                         }
2350                 }
2351
2352                 /*
2353                  * We need to try and merge add/drops of the same ref since we
2354                  * can run into issues with relocate dropping the implicit ref
2355                  * and then it being added back again before the drop can
2356                  * finish.  If we merged anything we need to re-loop so we can
2357                  * get a good ref.
2358                  */
2359                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2360                                          locked_ref);
2361
2362                 /*
2363                  * locked_ref is the head node, so we have to go one
2364                  * node back for any delayed ref updates
2365                  */
2366                 ref = select_delayed_ref(locked_ref);
2367
2368                 if (ref && ref->seq &&
2369                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2370                         /*
2371                          * there are still refs with lower seq numbers in the
2372                          * process of being added. Don't run this ref yet.
2373                          */
2374                         list_del_init(&locked_ref->cluster);
2375                         btrfs_delayed_ref_unlock(locked_ref);
2376                         locked_ref = NULL;
2377                         delayed_refs->num_heads_ready++;
2378                         spin_unlock(&delayed_refs->lock);
2379                         cond_resched();
2380                         spin_lock(&delayed_refs->lock);
2381                         continue;
2382                 }
2383
2384                 /*
2385                  * record the must insert reserved flag before we
2386                  * drop the spin lock.
2387                  */
2388                 must_insert_reserved = locked_ref->must_insert_reserved;
2389                 locked_ref->must_insert_reserved = 0;
2390
2391                 extent_op = locked_ref->extent_op;
2392                 locked_ref->extent_op = NULL;
2393
2394                 if (!ref) {
2395                         /* All delayed refs have been processed, Go ahead
2396                          * and send the head node to run_one_delayed_ref,
2397                          * so that any accounting fixes can happen
2398                          */
2399                         ref = &locked_ref->node;
2400
2401                         if (extent_op && must_insert_reserved) {
2402                                 btrfs_free_delayed_extent_op(extent_op);
2403                                 extent_op = NULL;
2404                         }
2405
2406                         if (extent_op) {
2407                                 spin_unlock(&delayed_refs->lock);
2408
2409                                 ret = run_delayed_extent_op(trans, root,
2410                                                             ref, extent_op);
2411                                 btrfs_free_delayed_extent_op(extent_op);
2412
2413                                 if (ret) {
2414                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2415                                         spin_lock(&delayed_refs->lock);
2416                                         btrfs_delayed_ref_unlock(locked_ref);
2417                                         return ret;
2418                                 }
2419
2420                                 goto next;
2421                         }
2422                 }
2423
2424                 ref->in_tree = 0;
2425                 rb_erase(&ref->rb_node, &delayed_refs->root);
2426                 delayed_refs->num_entries--;
2427                 if (!btrfs_delayed_ref_is_head(ref)) {
2428                         /*
2429                          * when we play the delayed ref, also correct the
2430                          * ref_mod on head
2431                          */
2432                         switch (ref->action) {
2433                         case BTRFS_ADD_DELAYED_REF:
2434                         case BTRFS_ADD_DELAYED_EXTENT:
2435                                 locked_ref->node.ref_mod -= ref->ref_mod;
2436                                 break;
2437                         case BTRFS_DROP_DELAYED_REF:
2438                                 locked_ref->node.ref_mod += ref->ref_mod;
2439                                 break;
2440                         default:
2441                                 WARN_ON(1);
2442                         }
2443                 } else {
2444                         list_del_init(&locked_ref->cluster);
2445                 }
2446                 spin_unlock(&delayed_refs->lock);
2447
2448                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2449                                           must_insert_reserved);
2450
2451                 btrfs_free_delayed_extent_op(extent_op);
2452                 if (ret) {
2453                         btrfs_delayed_ref_unlock(locked_ref);
2454                         btrfs_put_delayed_ref(ref);
2455                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2456                         spin_lock(&delayed_refs->lock);
2457                         return ret;
2458                 }
2459
2460                 /*
2461                  * If this node is a head, that means all the refs in this head
2462                  * have been dealt with, and we will pick the next head to deal
2463                  * with, so we must unlock the head and drop it from the cluster
2464                  * list before we release it.
2465                  */
2466                 if (btrfs_delayed_ref_is_head(ref)) {
2467                         btrfs_delayed_ref_unlock(locked_ref);
2468                         locked_ref = NULL;
2469                 }
2470                 btrfs_put_delayed_ref(ref);
2471                 count++;
2472 next:
2473                 cond_resched();
2474                 spin_lock(&delayed_refs->lock);
2475         }
2476         return count;
2477 }
2478
2479 #ifdef SCRAMBLE_DELAYED_REFS
2480 /*
2481  * Normally delayed refs get processed in ascending bytenr order. This
2482  * correlates in most cases to the order added. To expose dependencies on this
2483  * order, we start to process the tree in the middle instead of the beginning
2484  */
2485 static u64 find_middle(struct rb_root *root)
2486 {
2487         struct rb_node *n = root->rb_node;
2488         struct btrfs_delayed_ref_node *entry;
2489         int alt = 1;
2490         u64 middle;
2491         u64 first = 0, last = 0;
2492
2493         n = rb_first(root);
2494         if (n) {
2495                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2496                 first = entry->bytenr;
2497         }
2498         n = rb_last(root);
2499         if (n) {
2500                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2501                 last = entry->bytenr;
2502         }
2503         n = root->rb_node;
2504
2505         while (n) {
2506                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2507                 WARN_ON(!entry->in_tree);
2508
2509                 middle = entry->bytenr;
2510
2511                 if (alt)
2512                         n = n->rb_left;
2513                 else
2514                         n = n->rb_right;
2515
2516                 alt = 1 - alt;
2517         }
2518         return middle;
2519 }
2520 #endif
2521
2522 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2523                                          struct btrfs_fs_info *fs_info)
2524 {
2525         struct qgroup_update *qgroup_update;
2526         int ret = 0;
2527
2528         if (list_empty(&trans->qgroup_ref_list) !=
2529             !trans->delayed_ref_elem.seq) {
2530                 /* list without seq or seq without list */
2531                 btrfs_err(fs_info,
2532                         "qgroup accounting update error, list is%s empty, seq is %#x.%x",
2533                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2534                         (u32)(trans->delayed_ref_elem.seq >> 32),
2535                         (u32)trans->delayed_ref_elem.seq);
2536                 BUG();
2537         }
2538
2539         if (!trans->delayed_ref_elem.seq)
2540                 return 0;
2541
2542         while (!list_empty(&trans->qgroup_ref_list)) {
2543                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2544                                                  struct qgroup_update, list);
2545                 list_del(&qgroup_update->list);
2546                 if (!ret)
2547                         ret = btrfs_qgroup_account_ref(
2548                                         trans, fs_info, qgroup_update->node,
2549                                         qgroup_update->extent_op);
2550                 kfree(qgroup_update);
2551         }
2552
2553         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2554
2555         return ret;
2556 }
2557
2558 static int refs_newer(struct btrfs_delayed_ref_root *delayed_refs, int seq,
2559                       int count)
2560 {
2561         int val = atomic_read(&delayed_refs->ref_seq);
2562
2563         if (val < seq || val >= seq + count)
2564                 return 1;
2565         return 0;
2566 }
2567
2568 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2569 {
2570         u64 num_bytes;
2571
2572         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2573                              sizeof(struct btrfs_extent_inline_ref));
2574         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2575                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2576
2577         /*
2578          * We don't ever fill up leaves all the way so multiply by 2 just to be
2579          * closer to what we're really going to want to ouse.
2580          */
2581         return div64_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2582 }
2583
2584 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2585                                        struct btrfs_root *root)
2586 {
2587         struct btrfs_block_rsv *global_rsv;
2588         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2589         u64 num_bytes;
2590         int ret = 0;
2591
2592         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2593         num_heads = heads_to_leaves(root, num_heads);
2594         if (num_heads > 1)
2595                 num_bytes += (num_heads - 1) * root->leafsize;
2596         num_bytes <<= 1;
2597         global_rsv = &root->fs_info->global_block_rsv;
2598
2599         /*
2600          * If we can't allocate any more chunks lets make sure we have _lots_ of
2601          * wiggle room since running delayed refs can create more delayed refs.
2602          */
2603         if (global_rsv->space_info->full)
2604                 num_bytes <<= 1;
2605
2606         spin_lock(&global_rsv->lock);
2607         if (global_rsv->reserved <= num_bytes)
2608                 ret = 1;
2609         spin_unlock(&global_rsv->lock);
2610         return ret;
2611 }
2612
2613 /*
2614  * this starts processing the delayed reference count updates and
2615  * extent insertions we have queued up so far.  count can be
2616  * 0, which means to process everything in the tree at the start
2617  * of the run (but not newly added entries), or it can be some target
2618  * number you'd like to process.
2619  *
2620  * Returns 0 on success or if called with an aborted transaction
2621  * Returns <0 on error and aborts the transaction
2622  */
2623 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2624                            struct btrfs_root *root, unsigned long count)
2625 {
2626         struct rb_node *node;
2627         struct btrfs_delayed_ref_root *delayed_refs;
2628         struct btrfs_delayed_ref_node *ref;
2629         struct list_head cluster;
2630         int ret;
2631         u64 delayed_start;
2632         int run_all = count == (unsigned long)-1;
2633         int run_most = 0;
2634         int loops;
2635
2636         /* We'll clean this up in btrfs_cleanup_transaction */
2637         if (trans->aborted)
2638                 return 0;
2639
2640         if (root == root->fs_info->extent_root)
2641                 root = root->fs_info->tree_root;
2642
2643         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2644
2645         delayed_refs = &trans->transaction->delayed_refs;
2646         INIT_LIST_HEAD(&cluster);
2647         if (count == 0) {
2648                 count = delayed_refs->num_entries * 2;
2649                 run_most = 1;
2650         }
2651
2652         if (!run_all && !run_most) {
2653                 int old;
2654                 int seq = atomic_read(&delayed_refs->ref_seq);
2655
2656 progress:
2657                 old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2658                 if (old) {
2659                         DEFINE_WAIT(__wait);
2660                         if (delayed_refs->flushing ||
2661                             !btrfs_should_throttle_delayed_refs(trans, root))
2662                                 return 0;
2663
2664                         prepare_to_wait(&delayed_refs->wait, &__wait,
2665                                         TASK_UNINTERRUPTIBLE);
2666
2667                         old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2668                         if (old) {
2669                                 schedule();
2670                                 finish_wait(&delayed_refs->wait, &__wait);
2671
2672                                 if (!refs_newer(delayed_refs, seq, 256))
2673                                         goto progress;
2674                                 else
2675                                         return 0;
2676                         } else {
2677                                 finish_wait(&delayed_refs->wait, &__wait);
2678                                 goto again;
2679                         }
2680                 }
2681
2682         } else {
2683                 atomic_inc(&delayed_refs->procs_running_refs);
2684         }
2685
2686 again:
2687         loops = 0;
2688         spin_lock(&delayed_refs->lock);
2689
2690 #ifdef SCRAMBLE_DELAYED_REFS
2691         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2692 #endif
2693
2694         while (1) {
2695                 if (!(run_all || run_most) &&
2696                     !btrfs_should_throttle_delayed_refs(trans, root))
2697                         break;
2698
2699                 /*
2700                  * go find something we can process in the rbtree.  We start at
2701                  * the beginning of the tree, and then build a cluster
2702                  * of refs to process starting at the first one we are able to
2703                  * lock
2704                  */
2705                 delayed_start = delayed_refs->run_delayed_start;
2706                 ret = btrfs_find_ref_cluster(trans, &cluster,
2707                                              delayed_refs->run_delayed_start);
2708                 if (ret)
2709                         break;
2710
2711                 ret = run_clustered_refs(trans, root, &cluster);
2712                 if (ret < 0) {
2713                         btrfs_release_ref_cluster(&cluster);
2714                         spin_unlock(&delayed_refs->lock);
2715                         btrfs_abort_transaction(trans, root, ret);
2716                         atomic_dec(&delayed_refs->procs_running_refs);
2717                         wake_up(&delayed_refs->wait);
2718                         return ret;
2719                 }
2720
2721                 atomic_add(ret, &delayed_refs->ref_seq);
2722
2723                 count -= min_t(unsigned long, ret, count);
2724
2725                 if (count == 0)
2726                         break;
2727
2728                 if (delayed_start >= delayed_refs->run_delayed_start) {
2729                         if (loops == 0) {
2730                                 /*
2731                                  * btrfs_find_ref_cluster looped. let's do one
2732                                  * more cycle. if we don't run any delayed ref
2733                                  * during that cycle (because we can't because
2734                                  * all of them are blocked), bail out.
2735                                  */
2736                                 loops = 1;
2737                         } else {
2738                                 /*
2739                                  * no runnable refs left, stop trying
2740                                  */
2741                                 BUG_ON(run_all);
2742                                 break;
2743                         }
2744                 }
2745                 if (ret) {
2746                         /* refs were run, let's reset staleness detection */
2747                         loops = 0;
2748                 }
2749         }
2750
2751         if (run_all) {
2752                 if (!list_empty(&trans->new_bgs)) {
2753                         spin_unlock(&delayed_refs->lock);
2754                         btrfs_create_pending_block_groups(trans, root);
2755                         spin_lock(&delayed_refs->lock);
2756                 }
2757
2758                 node = rb_first(&delayed_refs->root);
2759                 if (!node)
2760                         goto out;
2761                 count = (unsigned long)-1;
2762
2763                 while (node) {
2764                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2765                                        rb_node);
2766                         if (btrfs_delayed_ref_is_head(ref)) {
2767                                 struct btrfs_delayed_ref_head *head;
2768
2769                                 head = btrfs_delayed_node_to_head(ref);
2770                                 atomic_inc(&ref->refs);
2771
2772                                 spin_unlock(&delayed_refs->lock);
2773                                 /*
2774                                  * Mutex was contended, block until it's
2775                                  * released and try again
2776                                  */
2777                                 mutex_lock(&head->mutex);
2778                                 mutex_unlock(&head->mutex);
2779
2780                                 btrfs_put_delayed_ref(ref);
2781                                 cond_resched();
2782                                 goto again;
2783                         }
2784                         node = rb_next(node);
2785                 }
2786                 spin_unlock(&delayed_refs->lock);
2787                 schedule_timeout(1);
2788                 goto again;
2789         }
2790 out:
2791         atomic_dec(&delayed_refs->procs_running_refs);
2792         smp_mb();
2793         if (waitqueue_active(&delayed_refs->wait))
2794                 wake_up(&delayed_refs->wait);
2795
2796         spin_unlock(&delayed_refs->lock);
2797         assert_qgroups_uptodate(trans);
2798         return 0;
2799 }
2800
2801 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2802                                 struct btrfs_root *root,
2803                                 u64 bytenr, u64 num_bytes, u64 flags,
2804                                 int level, int is_data)
2805 {
2806         struct btrfs_delayed_extent_op *extent_op;
2807         int ret;
2808
2809         extent_op = btrfs_alloc_delayed_extent_op();
2810         if (!extent_op)
2811                 return -ENOMEM;
2812
2813         extent_op->flags_to_set = flags;
2814         extent_op->update_flags = 1;
2815         extent_op->update_key = 0;
2816         extent_op->is_data = is_data ? 1 : 0;
2817         extent_op->level = level;
2818
2819         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2820                                           num_bytes, extent_op);
2821         if (ret)
2822                 btrfs_free_delayed_extent_op(extent_op);
2823         return ret;
2824 }
2825
2826 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2827                                       struct btrfs_root *root,
2828                                       struct btrfs_path *path,
2829                                       u64 objectid, u64 offset, u64 bytenr)
2830 {
2831         struct btrfs_delayed_ref_head *head;
2832         struct btrfs_delayed_ref_node *ref;
2833         struct btrfs_delayed_data_ref *data_ref;
2834         struct btrfs_delayed_ref_root *delayed_refs;
2835         struct rb_node *node;
2836         int ret = 0;
2837
2838         ret = -ENOENT;
2839         delayed_refs = &trans->transaction->delayed_refs;
2840         spin_lock(&delayed_refs->lock);
2841         head = btrfs_find_delayed_ref_head(trans, bytenr);
2842         if (!head)
2843                 goto out;
2844
2845         if (!mutex_trylock(&head->mutex)) {
2846                 atomic_inc(&head->node.refs);
2847                 spin_unlock(&delayed_refs->lock);
2848
2849                 btrfs_release_path(path);
2850
2851                 /*
2852                  * Mutex was contended, block until it's released and let
2853                  * caller try again
2854                  */
2855                 mutex_lock(&head->mutex);
2856                 mutex_unlock(&head->mutex);
2857                 btrfs_put_delayed_ref(&head->node);
2858                 return -EAGAIN;
2859         }
2860
2861         node = rb_prev(&head->node.rb_node);
2862         if (!node)
2863                 goto out_unlock;
2864
2865         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2866
2867         if (ref->bytenr != bytenr)
2868                 goto out_unlock;
2869
2870         ret = 1;
2871         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2872                 goto out_unlock;
2873
2874         data_ref = btrfs_delayed_node_to_data_ref(ref);
2875
2876         node = rb_prev(node);
2877         if (node) {
2878                 int seq = ref->seq;
2879
2880                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2881                 if (ref->bytenr == bytenr && ref->seq == seq)
2882                         goto out_unlock;
2883         }
2884
2885         if (data_ref->root != root->root_key.objectid ||
2886             data_ref->objectid != objectid || data_ref->offset != offset)
2887                 goto out_unlock;
2888
2889         ret = 0;
2890 out_unlock:
2891         mutex_unlock(&head->mutex);
2892 out:
2893         spin_unlock(&delayed_refs->lock);
2894         return ret;
2895 }
2896
2897 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2898                                         struct btrfs_root *root,
2899                                         struct btrfs_path *path,
2900                                         u64 objectid, u64 offset, u64 bytenr)
2901 {
2902         struct btrfs_root *extent_root = root->fs_info->extent_root;
2903         struct extent_buffer *leaf;
2904         struct btrfs_extent_data_ref *ref;
2905         struct btrfs_extent_inline_ref *iref;
2906         struct btrfs_extent_item *ei;
2907         struct btrfs_key key;
2908         u32 item_size;
2909         int ret;
2910
2911         key.objectid = bytenr;
2912         key.offset = (u64)-1;
2913         key.type = BTRFS_EXTENT_ITEM_KEY;
2914
2915         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2916         if (ret < 0)
2917                 goto out;
2918         BUG_ON(ret == 0); /* Corruption */
2919
2920         ret = -ENOENT;
2921         if (path->slots[0] == 0)
2922                 goto out;
2923
2924         path->slots[0]--;
2925         leaf = path->nodes[0];
2926         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2927
2928         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2929                 goto out;
2930
2931         ret = 1;
2932         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2933 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2934         if (item_size < sizeof(*ei)) {
2935                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2936                 goto out;
2937         }
2938 #endif
2939         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2940
2941         if (item_size != sizeof(*ei) +
2942             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2943                 goto out;
2944
2945         if (btrfs_extent_generation(leaf, ei) <=
2946             btrfs_root_last_snapshot(&root->root_item))
2947                 goto out;
2948
2949         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2950         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2951             BTRFS_EXTENT_DATA_REF_KEY)
2952                 goto out;
2953
2954         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2955         if (btrfs_extent_refs(leaf, ei) !=
2956             btrfs_extent_data_ref_count(leaf, ref) ||
2957             btrfs_extent_data_ref_root(leaf, ref) !=
2958             root->root_key.objectid ||
2959             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2960             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2961                 goto out;
2962
2963         ret = 0;
2964 out:
2965         return ret;
2966 }
2967
2968 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2969                           struct btrfs_root *root,
2970                           u64 objectid, u64 offset, u64 bytenr)
2971 {
2972         struct btrfs_path *path;
2973         int ret;
2974         int ret2;
2975
2976         path = btrfs_alloc_path();
2977         if (!path)
2978                 return -ENOENT;
2979
2980         do {
2981                 ret = check_committed_ref(trans, root, path, objectid,
2982                                           offset, bytenr);
2983                 if (ret && ret != -ENOENT)
2984                         goto out;
2985
2986                 ret2 = check_delayed_ref(trans, root, path, objectid,
2987                                          offset, bytenr);
2988         } while (ret2 == -EAGAIN);
2989
2990         if (ret2 && ret2 != -ENOENT) {
2991                 ret = ret2;
2992                 goto out;
2993         }
2994
2995         if (ret != -ENOENT || ret2 != -ENOENT)
2996                 ret = 0;
2997 out:
2998         btrfs_free_path(path);
2999         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3000                 WARN_ON(ret > 0);
3001         return ret;
3002 }
3003
3004 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3005                            struct btrfs_root *root,
3006                            struct extent_buffer *buf,
3007                            int full_backref, int inc, int for_cow)
3008 {
3009         u64 bytenr;
3010         u64 num_bytes;
3011         u64 parent;
3012         u64 ref_root;
3013         u32 nritems;
3014         struct btrfs_key key;
3015         struct btrfs_file_extent_item *fi;
3016         int i;
3017         int level;
3018         int ret = 0;
3019         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3020                             u64, u64, u64, u64, u64, u64, int);
3021
3022         ref_root = btrfs_header_owner(buf);
3023         nritems = btrfs_header_nritems(buf);
3024         level = btrfs_header_level(buf);
3025
3026         if (!root->ref_cows && level == 0)
3027                 return 0;
3028
3029         if (inc)
3030                 process_func = btrfs_inc_extent_ref;
3031         else
3032                 process_func = btrfs_free_extent;
3033
3034         if (full_backref)
3035                 parent = buf->start;
3036         else
3037                 parent = 0;
3038
3039         for (i = 0; i < nritems; i++) {
3040                 if (level == 0) {
3041                         btrfs_item_key_to_cpu(buf, &key, i);
3042                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3043                                 continue;
3044                         fi = btrfs_item_ptr(buf, i,
3045                                             struct btrfs_file_extent_item);
3046                         if (btrfs_file_extent_type(buf, fi) ==
3047                             BTRFS_FILE_EXTENT_INLINE)
3048                                 continue;
3049                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3050                         if (bytenr == 0)
3051                                 continue;
3052
3053                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3054                         key.offset -= btrfs_file_extent_offset(buf, fi);
3055                         ret = process_func(trans, root, bytenr, num_bytes,
3056                                            parent, ref_root, key.objectid,
3057                                            key.offset, for_cow);
3058                         if (ret)
3059                                 goto fail;
3060                 } else {
3061                         bytenr = btrfs_node_blockptr(buf, i);
3062                         num_bytes = btrfs_level_size(root, level - 1);
3063                         ret = process_func(trans, root, bytenr, num_bytes,
3064                                            parent, ref_root, level - 1, 0,
3065                                            for_cow);
3066                         if (ret)
3067                                 goto fail;
3068                 }
3069         }
3070         return 0;
3071 fail:
3072         return ret;
3073 }
3074
3075 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3076                   struct extent_buffer *buf, int full_backref, int for_cow)
3077 {
3078         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
3079 }
3080
3081 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3082                   struct extent_buffer *buf, int full_backref, int for_cow)
3083 {
3084         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
3085 }
3086
3087 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3088                                  struct btrfs_root *root,
3089                                  struct btrfs_path *path,
3090                                  struct btrfs_block_group_cache *cache)
3091 {
3092         int ret;
3093         struct btrfs_root *extent_root = root->fs_info->extent_root;
3094         unsigned long bi;
3095         struct extent_buffer *leaf;
3096
3097         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3098         if (ret < 0)
3099                 goto fail;
3100         BUG_ON(ret); /* Corruption */
3101
3102         leaf = path->nodes[0];
3103         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3104         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3105         btrfs_mark_buffer_dirty(leaf);
3106         btrfs_release_path(path);
3107 fail:
3108         if (ret) {
3109                 btrfs_abort_transaction(trans, root, ret);
3110                 return ret;
3111         }
3112         return 0;
3113
3114 }
3115
3116 static struct btrfs_block_group_cache *
3117 next_block_group(struct btrfs_root *root,
3118                  struct btrfs_block_group_cache *cache)
3119 {
3120         struct rb_node *node;
3121         spin_lock(&root->fs_info->block_group_cache_lock);
3122         node = rb_next(&cache->cache_node);
3123         btrfs_put_block_group(cache);
3124         if (node) {
3125                 cache = rb_entry(node, struct btrfs_block_group_cache,
3126                                  cache_node);
3127                 btrfs_get_block_group(cache);
3128         } else
3129                 cache = NULL;
3130         spin_unlock(&root->fs_info->block_group_cache_lock);
3131         return cache;
3132 }
3133
3134 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3135                             struct btrfs_trans_handle *trans,
3136                             struct btrfs_path *path)
3137 {
3138         struct btrfs_root *root = block_group->fs_info->tree_root;
3139         struct inode *inode = NULL;
3140         u64 alloc_hint = 0;
3141         int dcs = BTRFS_DC_ERROR;
3142         int num_pages = 0;
3143         int retries = 0;
3144         int ret = 0;
3145
3146         /*
3147          * If this block group is smaller than 100 megs don't bother caching the
3148          * block group.
3149          */
3150         if (block_group->key.offset < (100 * 1024 * 1024)) {
3151                 spin_lock(&block_group->lock);
3152                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3153                 spin_unlock(&block_group->lock);
3154                 return 0;
3155         }
3156
3157 again:
3158         inode = lookup_free_space_inode(root, block_group, path);
3159         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3160                 ret = PTR_ERR(inode);
3161                 btrfs_release_path(path);
3162                 goto out;
3163         }
3164
3165         if (IS_ERR(inode)) {
3166                 BUG_ON(retries);
3167                 retries++;
3168
3169                 if (block_group->ro)
3170                         goto out_free;
3171
3172                 ret = create_free_space_inode(root, trans, block_group, path);
3173                 if (ret)
3174                         goto out_free;
3175                 goto again;
3176         }
3177
3178         /* We've already setup this transaction, go ahead and exit */
3179         if (block_group->cache_generation == trans->transid &&
3180             i_size_read(inode)) {
3181                 dcs = BTRFS_DC_SETUP;
3182                 goto out_put;
3183         }
3184
3185         /*
3186          * We want to set the generation to 0, that way if anything goes wrong
3187          * from here on out we know not to trust this cache when we load up next
3188          * time.
3189          */
3190         BTRFS_I(inode)->generation = 0;
3191         ret = btrfs_update_inode(trans, root, inode);
3192         WARN_ON(ret);
3193
3194         if (i_size_read(inode) > 0) {
3195                 ret = btrfs_check_trunc_cache_free_space(root,
3196                                         &root->fs_info->global_block_rsv);
3197                 if (ret)
3198                         goto out_put;
3199
3200                 ret = btrfs_truncate_free_space_cache(root, trans, path,
3201                                                       inode);
3202                 if (ret)
3203                         goto out_put;
3204         }
3205
3206         spin_lock(&block_group->lock);
3207         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3208             !btrfs_test_opt(root, SPACE_CACHE)) {
3209                 /*
3210                  * don't bother trying to write stuff out _if_
3211                  * a) we're not cached,
3212                  * b) we're with nospace_cache mount option.
3213                  */
3214                 dcs = BTRFS_DC_WRITTEN;
3215                 spin_unlock(&block_group->lock);
3216                 goto out_put;
3217         }
3218         spin_unlock(&block_group->lock);
3219
3220         /*
3221          * Try to preallocate enough space based on how big the block group is.
3222          * Keep in mind this has to include any pinned space which could end up
3223          * taking up quite a bit since it's not folded into the other space
3224          * cache.
3225          */
3226         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3227         if (!num_pages)
3228                 num_pages = 1;
3229
3230         num_pages *= 16;
3231         num_pages *= PAGE_CACHE_SIZE;
3232
3233         ret = btrfs_check_data_free_space(inode, num_pages);
3234         if (ret)
3235                 goto out_put;
3236
3237         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3238                                               num_pages, num_pages,
3239                                               &alloc_hint);
3240         if (!ret)
3241                 dcs = BTRFS_DC_SETUP;
3242         btrfs_free_reserved_data_space(inode, num_pages);
3243
3244 out_put:
3245         iput(inode);
3246 out_free:
3247         btrfs_release_path(path);
3248 out:
3249         spin_lock(&block_group->lock);
3250         if (!ret && dcs == BTRFS_DC_SETUP)
3251                 block_group->cache_generation = trans->transid;
3252         block_group->disk_cache_state = dcs;
3253         spin_unlock(&block_group->lock);
3254
3255         return ret;
3256 }
3257
3258 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3259                                    struct btrfs_root *root)
3260 {
3261         struct btrfs_block_group_cache *cache;
3262         int err = 0;
3263         struct btrfs_path *path;
3264         u64 last = 0;
3265
3266         path = btrfs_alloc_path();
3267         if (!path)
3268                 return -ENOMEM;
3269
3270 again:
3271         while (1) {
3272                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3273                 while (cache) {
3274                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3275                                 break;
3276                         cache = next_block_group(root, cache);
3277                 }
3278                 if (!cache) {
3279                         if (last == 0)
3280                                 break;
3281                         last = 0;
3282                         continue;
3283                 }
3284                 err = cache_save_setup(cache, trans, path);
3285                 last = cache->key.objectid + cache->key.offset;
3286                 btrfs_put_block_group(cache);
3287         }
3288
3289         while (1) {
3290                 if (last == 0) {
3291                         err = btrfs_run_delayed_refs(trans, root,
3292                                                      (unsigned long)-1);
3293                         if (err) /* File system offline */
3294                                 goto out;
3295                 }
3296
3297                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3298                 while (cache) {
3299                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3300                                 btrfs_put_block_group(cache);
3301                                 goto again;
3302                         }
3303
3304                         if (cache->dirty)
3305                                 break;
3306                         cache = next_block_group(root, cache);
3307                 }
3308                 if (!cache) {
3309                         if (last == 0)
3310                                 break;
3311                         last = 0;
3312                         continue;
3313                 }
3314
3315                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3316                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3317                 cache->dirty = 0;
3318                 last = cache->key.objectid + cache->key.offset;
3319
3320                 err = write_one_cache_group(trans, root, path, cache);
3321                 if (err) /* File system offline */
3322                         goto out;
3323
3324                 btrfs_put_block_group(cache);
3325         }
3326
3327         while (1) {
3328                 /*
3329                  * I don't think this is needed since we're just marking our
3330                  * preallocated extent as written, but just in case it can't
3331                  * hurt.
3332                  */
3333                 if (last == 0) {
3334                         err = btrfs_run_delayed_refs(trans, root,
3335                                                      (unsigned long)-1);
3336                         if (err) /* File system offline */
3337                                 goto out;
3338                 }
3339
3340                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3341                 while (cache) {
3342                         /*
3343                          * Really this shouldn't happen, but it could if we
3344                          * couldn't write the entire preallocated extent and
3345                          * splitting the extent resulted in a new block.
3346                          */
3347                         if (cache->dirty) {
3348                                 btrfs_put_block_group(cache);
3349                                 goto again;
3350                         }
3351                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3352                                 break;
3353                         cache = next_block_group(root, cache);
3354                 }
3355                 if (!cache) {
3356                         if (last == 0)
3357                                 break;
3358                         last = 0;
3359                         continue;
3360                 }
3361
3362                 err = btrfs_write_out_cache(root, trans, cache, path);
3363
3364                 /*
3365                  * If we didn't have an error then the cache state is still
3366                  * NEED_WRITE, so we can set it to WRITTEN.
3367                  */
3368                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3369                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3370                 last = cache->key.objectid + cache->key.offset;
3371                 btrfs_put_block_group(cache);
3372         }
3373 out:
3374
3375         btrfs_free_path(path);
3376         return err;
3377 }
3378
3379 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3380 {
3381         struct btrfs_block_group_cache *block_group;
3382         int readonly = 0;
3383
3384         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3385         if (!block_group || block_group->ro)
3386                 readonly = 1;
3387         if (block_group)
3388                 btrfs_put_block_group(block_group);
3389         return readonly;
3390 }
3391
3392 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3393                              u64 total_bytes, u64 bytes_used,
3394                              struct btrfs_space_info **space_info)
3395 {
3396         struct btrfs_space_info *found;
3397         int i;
3398         int factor;
3399         int ret;
3400
3401         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3402                      BTRFS_BLOCK_GROUP_RAID10))
3403                 factor = 2;
3404         else
3405                 factor = 1;
3406
3407         found = __find_space_info(info, flags);
3408         if (found) {
3409                 spin_lock(&found->lock);
3410                 found->total_bytes += total_bytes;
3411                 found->disk_total += total_bytes * factor;
3412                 found->bytes_used += bytes_used;
3413                 found->disk_used += bytes_used * factor;
3414                 found->full = 0;
3415                 spin_unlock(&found->lock);
3416                 *space_info = found;
3417                 return 0;
3418         }
3419         found = kzalloc(sizeof(*found), GFP_NOFS);
3420         if (!found)
3421                 return -ENOMEM;
3422
3423         ret = percpu_counter_init(&found->total_bytes_pinned, 0);
3424         if (ret) {
3425                 kfree(found);
3426                 return ret;
3427         }
3428
3429         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3430                 INIT_LIST_HEAD(&found->block_groups[i]);
3431         init_rwsem(&found->groups_sem);
3432         spin_lock_init(&found->lock);
3433         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3434         found->total_bytes = total_bytes;
3435         found->disk_total = total_bytes * factor;
3436         found->bytes_used = bytes_used;
3437         found->disk_used = bytes_used * factor;
3438         found->bytes_pinned = 0;
3439         found->bytes_reserved = 0;
3440         found->bytes_readonly = 0;
3441         found->bytes_may_use = 0;
3442         found->full = 0;
3443         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3444         found->chunk_alloc = 0;
3445         found->flush = 0;
3446         init_waitqueue_head(&found->wait);
3447         *space_info = found;
3448         list_add_rcu(&found->list, &info->space_info);
3449         if (flags & BTRFS_BLOCK_GROUP_DATA)
3450                 info->data_sinfo = found;
3451         return 0;
3452 }
3453
3454 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3455 {
3456         u64 extra_flags = chunk_to_extended(flags) &
3457                                 BTRFS_EXTENDED_PROFILE_MASK;
3458
3459         write_seqlock(&fs_info->profiles_lock);
3460         if (flags & BTRFS_BLOCK_GROUP_DATA)
3461                 fs_info->avail_data_alloc_bits |= extra_flags;
3462         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3463                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3464         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3465                 fs_info->avail_system_alloc_bits |= extra_flags;
3466         write_sequnlock(&fs_info->profiles_lock);
3467 }
3468
3469 /*
3470  * returns target flags in extended format or 0 if restripe for this
3471  * chunk_type is not in progress
3472  *
3473  * should be called with either volume_mutex or balance_lock held
3474  */
3475 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3476 {
3477         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3478         u64 target = 0;
3479
3480         if (!bctl)
3481                 return 0;
3482
3483         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3484             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3485                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3486         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3487                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3488                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3489         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3490                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3491                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3492         }
3493
3494         return target;
3495 }
3496
3497 /*
3498  * @flags: available profiles in extended format (see ctree.h)
3499  *
3500  * Returns reduced profile in chunk format.  If profile changing is in
3501  * progress (either running or paused) picks the target profile (if it's
3502  * already available), otherwise falls back to plain reducing.
3503  */
3504 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3505 {
3506         /*
3507          * we add in the count of missing devices because we want
3508          * to make sure that any RAID levels on a degraded FS
3509          * continue to be honored.
3510          */
3511         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3512                 root->fs_info->fs_devices->missing_devices;
3513         u64 target;
3514         u64 tmp;
3515
3516         /*
3517          * see if restripe for this chunk_type is in progress, if so
3518          * try to reduce to the target profile
3519          */
3520         spin_lock(&root->fs_info->balance_lock);
3521         target = get_restripe_target(root->fs_info, flags);
3522         if (target) {
3523                 /* pick target profile only if it's already available */
3524                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3525                         spin_unlock(&root->fs_info->balance_lock);
3526                         return extended_to_chunk(target);
3527                 }
3528         }
3529         spin_unlock(&root->fs_info->balance_lock);
3530
3531         /* First, mask out the RAID levels which aren't possible */
3532         if (num_devices == 1)
3533                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3534                            BTRFS_BLOCK_GROUP_RAID5);
3535         if (num_devices < 3)
3536                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3537         if (num_devices < 4)
3538                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3539
3540         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3541                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3542                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3543         flags &= ~tmp;
3544
3545         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3546                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3547         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3548                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3549         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3550                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3551         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3552                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3553         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3554                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3555
3556         return extended_to_chunk(flags | tmp);
3557 }
3558
3559 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3560 {
3561         unsigned seq;
3562
3563         do {
3564                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3565
3566                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3567                         flags |= root->fs_info->avail_data_alloc_bits;
3568                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3569                         flags |= root->fs_info->avail_system_alloc_bits;
3570                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3571                         flags |= root->fs_info->avail_metadata_alloc_bits;
3572         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3573
3574         return btrfs_reduce_alloc_profile(root, flags);
3575 }
3576
3577 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3578 {
3579         u64 flags;
3580         u64 ret;
3581
3582         if (data)
3583                 flags = BTRFS_BLOCK_GROUP_DATA;
3584         else if (root == root->fs_info->chunk_root)
3585                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3586         else
3587                 flags = BTRFS_BLOCK_GROUP_METADATA;
3588
3589         ret = get_alloc_profile(root, flags);
3590         return ret;
3591 }
3592
3593 /*
3594  * This will check the space that the inode allocates from to make sure we have
3595  * enough space for bytes.
3596  */
3597 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3598 {
3599         struct btrfs_space_info *data_sinfo;
3600         struct btrfs_root *root = BTRFS_I(inode)->root;
3601         struct btrfs_fs_info *fs_info = root->fs_info;
3602         u64 used;
3603         int ret = 0, committed = 0, alloc_chunk = 1;
3604
3605         /* make sure bytes are sectorsize aligned */
3606         bytes = ALIGN(bytes, root->sectorsize);
3607
3608         if (root == root->fs_info->tree_root ||
3609             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3610                 alloc_chunk = 0;
3611                 committed = 1;
3612         }
3613
3614         data_sinfo = fs_info->data_sinfo;
3615         if (!data_sinfo)
3616                 goto alloc;
3617
3618 again:
3619         /* make sure we have enough space to handle the data first */
3620         spin_lock(&data_sinfo->lock);
3621         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3622                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3623                 data_sinfo->bytes_may_use;
3624
3625         if (used + bytes > data_sinfo->total_bytes) {
3626                 struct btrfs_trans_handle *trans;
3627
3628                 /*
3629                  * if we don't have enough free bytes in this space then we need
3630                  * to alloc a new chunk.
3631                  */
3632                 if (!data_sinfo->full && alloc_chunk) {
3633                         u64 alloc_target;
3634
3635                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3636                         spin_unlock(&data_sinfo->lock);
3637 alloc:
3638                         alloc_target = btrfs_get_alloc_profile(root, 1);
3639                         trans = btrfs_join_transaction(root);
3640                         if (IS_ERR(trans))
3641                                 return PTR_ERR(trans);
3642
3643                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3644                                              alloc_target,
3645                                              CHUNK_ALLOC_NO_FORCE);
3646                         btrfs_end_transaction(trans, root);
3647                         if (ret < 0) {
3648                                 if (ret != -ENOSPC)
3649                                         return ret;
3650                                 else
3651                                         goto commit_trans;
3652                         }
3653
3654                         if (!data_sinfo)
3655                                 data_sinfo = fs_info->data_sinfo;
3656
3657                         goto again;
3658                 }
3659
3660                 /*
3661                  * If we don't have enough pinned space to deal with this
3662                  * allocation don't bother committing the transaction.
3663                  */
3664                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
3665                                            bytes) < 0)
3666                         committed = 1;
3667                 spin_unlock(&data_sinfo->lock);
3668
3669                 /* commit the current transaction and try again */
3670 commit_trans:
3671                 if (!committed &&
3672                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3673                         committed = 1;
3674
3675                         trans = btrfs_join_transaction(root);
3676                         if (IS_ERR(trans))
3677                                 return PTR_ERR(trans);
3678                         ret = btrfs_commit_transaction(trans, root);
3679                         if (ret)
3680                                 return ret;
3681                         goto again;
3682                 }
3683
3684                 return -ENOSPC;
3685         }
3686         data_sinfo->bytes_may_use += bytes;
3687         trace_btrfs_space_reservation(root->fs_info, "space_info",
3688                                       data_sinfo->flags, bytes, 1);
3689         spin_unlock(&data_sinfo->lock);
3690
3691         return 0;
3692 }
3693
3694 /*
3695  * Called if we need to clear a data reservation for this inode.
3696  */
3697 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3698 {
3699         struct btrfs_root *root = BTRFS_I(inode)->root;
3700         struct btrfs_space_info *data_sinfo;
3701
3702         /* make sure bytes are sectorsize aligned */
3703         bytes = ALIGN(bytes, root->sectorsize);
3704
3705         data_sinfo = root->fs_info->data_sinfo;
3706         spin_lock(&data_sinfo->lock);
3707         WARN_ON(data_sinfo->bytes_may_use < bytes);
3708         data_sinfo->bytes_may_use -= bytes;
3709         trace_btrfs_space_reservation(root->fs_info, "space_info",
3710                                       data_sinfo->flags, bytes, 0);
3711         spin_unlock(&data_sinfo->lock);
3712 }
3713
3714 static void force_metadata_allocation(struct btrfs_fs_info *info)
3715 {
3716         struct list_head *head = &info->space_info;
3717         struct btrfs_space_info *found;
3718
3719         rcu_read_lock();
3720         list_for_each_entry_rcu(found, head, list) {
3721                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3722                         found->force_alloc = CHUNK_ALLOC_FORCE;
3723         }
3724         rcu_read_unlock();
3725 }
3726
3727 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3728 {
3729         return (global->size << 1);
3730 }
3731
3732 static int should_alloc_chunk(struct btrfs_root *root,
3733                               struct btrfs_space_info *sinfo, int force)
3734 {
3735         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3736         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3737         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3738         u64 thresh;
3739
3740         if (force == CHUNK_ALLOC_FORCE)
3741                 return 1;
3742
3743         /*
3744          * We need to take into account the global rsv because for all intents
3745          * and purposes it's used space.  Don't worry about locking the
3746          * global_rsv, it doesn't change except when the transaction commits.
3747          */
3748         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3749                 num_allocated += calc_global_rsv_need_space(global_rsv);
3750
3751         /*
3752          * in limited mode, we want to have some free space up to
3753          * about 1% of the FS size.
3754          */
3755         if (force == CHUNK_ALLOC_LIMITED) {
3756                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3757                 thresh = max_t(u64, 64 * 1024 * 1024,
3758                                div_factor_fine(thresh, 1));
3759
3760                 if (num_bytes - num_allocated < thresh)
3761                         return 1;
3762         }
3763
3764         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3765                 return 0;
3766         return 1;
3767 }
3768
3769 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3770 {
3771         u64 num_dev;
3772
3773         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3774                     BTRFS_BLOCK_GROUP_RAID0 |
3775                     BTRFS_BLOCK_GROUP_RAID5 |
3776                     BTRFS_BLOCK_GROUP_RAID6))
3777                 num_dev = root->fs_info->fs_devices->rw_devices;
3778         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3779                 num_dev = 2;
3780         else
3781                 num_dev = 1;    /* DUP or single */
3782
3783         /* metadata for updaing devices and chunk tree */
3784         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3785 }
3786
3787 static void check_system_chunk(struct btrfs_trans_handle *trans,
3788                                struct btrfs_root *root, u64 type)
3789 {
3790         struct btrfs_space_info *info;
3791         u64 left;
3792         u64 thresh;
3793
3794         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3795         spin_lock(&info->lock);
3796         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3797                 info->bytes_reserved - info->bytes_readonly;
3798         spin_unlock(&info->lock);
3799
3800         thresh = get_system_chunk_thresh(root, type);
3801         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3802                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3803                         left, thresh, type);
3804                 dump_space_info(info, 0, 0);
3805         }
3806
3807         if (left < thresh) {
3808                 u64 flags;
3809
3810                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3811                 btrfs_alloc_chunk(trans, root, flags);
3812         }
3813 }
3814
3815 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3816                           struct btrfs_root *extent_root, u64 flags, int force)
3817 {
3818         struct btrfs_space_info *space_info;
3819         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3820         int wait_for_alloc = 0;
3821         int ret = 0;
3822
3823         /* Don't re-enter if we're already allocating a chunk */
3824         if (trans->allocating_chunk)
3825                 return -ENOSPC;
3826
3827         space_info = __find_space_info(extent_root->fs_info, flags);
3828         if (!space_info) {
3829                 ret = update_space_info(extent_root->fs_info, flags,
3830                                         0, 0, &space_info);
3831                 BUG_ON(ret); /* -ENOMEM */
3832         }
3833         BUG_ON(!space_info); /* Logic error */
3834
3835 again:
3836         spin_lock(&space_info->lock);
3837         if (force < space_info->force_alloc)
3838                 force = space_info->force_alloc;
3839         if (space_info->full) {
3840                 if (should_alloc_chunk(extent_root, space_info, force))
3841                         ret = -ENOSPC;
3842                 else
3843                         ret = 0;
3844                 spin_unlock(&space_info->lock);
3845                 return ret;
3846         }
3847
3848         if (!should_alloc_chunk(extent_root, space_info, force)) {
3849                 spin_unlock(&space_info->lock);
3850                 return 0;
3851         } else if (space_info->chunk_alloc) {
3852                 wait_for_alloc = 1;
3853         } else {
3854                 space_info->chunk_alloc = 1;
3855         }
3856
3857         spin_unlock(&space_info->lock);
3858
3859         mutex_lock(&fs_info->chunk_mutex);
3860
3861         /*
3862          * The chunk_mutex is held throughout the entirety of a chunk
3863          * allocation, so once we've acquired the chunk_mutex we know that the
3864          * other guy is done and we need to recheck and see if we should
3865          * allocate.
3866          */
3867         if (wait_for_alloc) {
3868                 mutex_unlock(&fs_info->chunk_mutex);
3869                 wait_for_alloc = 0;
3870                 goto again;
3871         }
3872
3873         trans->allocating_chunk = true;
3874
3875         /*
3876          * If we have mixed data/metadata chunks we want to make sure we keep
3877          * allocating mixed chunks instead of individual chunks.
3878          */
3879         if (btrfs_mixed_space_info(space_info))
3880                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3881
3882         /*
3883          * if we're doing a data chunk, go ahead and make sure that
3884          * we keep a reasonable number of metadata chunks allocated in the
3885          * FS as well.
3886          */
3887         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3888                 fs_info->data_chunk_allocations++;
3889                 if (!(fs_info->data_chunk_allocations %
3890                       fs_info->metadata_ratio))
3891                         force_metadata_allocation(fs_info);
3892         }
3893
3894         /*
3895          * Check if we have enough space in SYSTEM chunk because we may need
3896          * to update devices.
3897          */
3898         check_system_chunk(trans, extent_root, flags);
3899
3900         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3901         trans->allocating_chunk = false;
3902
3903         spin_lock(&space_info->lock);
3904         if (ret < 0 && ret != -ENOSPC)
3905                 goto out;
3906         if (ret)
3907                 space_info->full = 1;
3908         else
3909                 ret = 1;
3910
3911         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3912 out:
3913         space_info->chunk_alloc = 0;
3914         spin_unlock(&space_info->lock);
3915         mutex_unlock(&fs_info->chunk_mutex);
3916         return ret;
3917 }
3918
3919 static int can_overcommit(struct btrfs_root *root,
3920                           struct btrfs_space_info *space_info, u64 bytes,
3921                           enum btrfs_reserve_flush_enum flush)
3922 {
3923         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3924         u64 profile = btrfs_get_alloc_profile(root, 0);
3925         u64 space_size;
3926         u64 avail;
3927         u64 used;
3928         u64 to_add;
3929
3930         used = space_info->bytes_used + space_info->bytes_reserved +
3931                 space_info->bytes_pinned + space_info->bytes_readonly;
3932
3933         /*
3934          * We only want to allow over committing if we have lots of actual space
3935          * free, but if we don't have enough space to handle the global reserve
3936          * space then we could end up having a real enospc problem when trying
3937          * to allocate a chunk or some other such important allocation.
3938          */
3939         spin_lock(&global_rsv->lock);
3940         space_size = calc_global_rsv_need_space(global_rsv);
3941         spin_unlock(&global_rsv->lock);
3942         if (used + space_size >= space_info->total_bytes)
3943                 return 0;
3944
3945         used += space_info->bytes_may_use;
3946
3947         spin_lock(&root->fs_info->free_chunk_lock);
3948         avail = root->fs_info->free_chunk_space;
3949         spin_unlock(&root->fs_info->free_chunk_lock);
3950
3951         /*
3952          * If we have dup, raid1 or raid10 then only half of the free
3953          * space is actually useable.  For raid56, the space info used
3954          * doesn't include the parity drive, so we don't have to
3955          * change the math
3956          */
3957         if (profile & (BTRFS_BLOCK_GROUP_DUP |
3958                        BTRFS_BLOCK_GROUP_RAID1 |
3959                        BTRFS_BLOCK_GROUP_RAID10))
3960                 avail >>= 1;
3961
3962         to_add = space_info->total_bytes;
3963
3964         /*
3965          * If we aren't flushing all things, let us overcommit up to
3966          * 1/2th of the space. If we can flush, don't let us overcommit
3967          * too much, let it overcommit up to 1/8 of the space.
3968          */
3969         if (flush == BTRFS_RESERVE_FLUSH_ALL)
3970                 to_add >>= 3;
3971         else
3972                 to_add >>= 1;
3973
3974         /*
3975          * Limit the overcommit to the amount of free space we could possibly
3976          * allocate for chunks.
3977          */
3978         to_add = min(avail, to_add);
3979
3980         if (used + bytes < space_info->total_bytes + to_add)
3981                 return 1;
3982         return 0;
3983 }
3984
3985 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
3986                                          unsigned long nr_pages)
3987 {
3988         struct super_block *sb = root->fs_info->sb;
3989
3990         if (down_read_trylock(&sb->s_umount)) {
3991                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
3992                 up_read(&sb->s_umount);
3993         } else {
3994                 /*
3995                  * We needn't worry the filesystem going from r/w to r/o though
3996                  * we don't acquire ->s_umount mutex, because the filesystem
3997                  * should guarantee the delalloc inodes list be empty after
3998                  * the filesystem is readonly(all dirty pages are written to
3999                  * the disk).
4000                  */
4001                 btrfs_start_all_delalloc_inodes(root->fs_info, 0);
4002                 if (!current->journal_info)
4003                         btrfs_wait_all_ordered_extents(root->fs_info, 0);
4004         }
4005 }
4006
4007 /*
4008  * shrink metadata reservation for delalloc
4009  */
4010 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4011                             bool wait_ordered)
4012 {
4013         struct btrfs_block_rsv *block_rsv;
4014         struct btrfs_space_info *space_info;
4015         struct btrfs_trans_handle *trans;
4016         u64 delalloc_bytes;
4017         u64 max_reclaim;
4018         long time_left;
4019         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
4020         int loops = 0;
4021         enum btrfs_reserve_flush_enum flush;
4022
4023         trans = (struct btrfs_trans_handle *)current->journal_info;
4024         block_rsv = &root->fs_info->delalloc_block_rsv;
4025         space_info = block_rsv->space_info;
4026
4027         smp_mb();
4028         delalloc_bytes = percpu_counter_sum_positive(
4029                                                 &root->fs_info->delalloc_bytes);
4030         if (delalloc_bytes == 0) {
4031                 if (trans)
4032                         return;
4033                 btrfs_wait_all_ordered_extents(root->fs_info, 0);
4034                 return;
4035         }
4036
4037         while (delalloc_bytes && loops < 3) {
4038                 max_reclaim = min(delalloc_bytes, to_reclaim);
4039                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4040                 btrfs_writeback_inodes_sb_nr(root, nr_pages);
4041                 /*
4042                  * We need to wait for the async pages to actually start before
4043                  * we do anything.
4044                  */
4045                 wait_event(root->fs_info->async_submit_wait,
4046                            !atomic_read(&root->fs_info->async_delalloc_pages));
4047
4048                 if (!trans)
4049                         flush = BTRFS_RESERVE_FLUSH_ALL;
4050                 else
4051                         flush = BTRFS_RESERVE_NO_FLUSH;
4052                 spin_lock(&space_info->lock);
4053                 if (can_overcommit(root, space_info, orig, flush)) {
4054                         spin_unlock(&space_info->lock);
4055                         break;
4056                 }
4057                 spin_unlock(&space_info->lock);
4058
4059                 loops++;
4060                 if (wait_ordered && !trans) {
4061                         btrfs_wait_all_ordered_extents(root->fs_info, 0);
4062                 } else {
4063                         time_left = schedule_timeout_killable(1);
4064                         if (time_left)
4065                                 break;
4066                 }
4067                 smp_mb();
4068                 delalloc_bytes = percpu_counter_sum_positive(
4069                                                 &root->fs_info->delalloc_bytes);
4070         }
4071 }
4072
4073 /**
4074  * maybe_commit_transaction - possibly commit the transaction if its ok to
4075  * @root - the root we're allocating for
4076  * @bytes - the number of bytes we want to reserve
4077  * @force - force the commit
4078  *
4079  * This will check to make sure that committing the transaction will actually
4080  * get us somewhere and then commit the transaction if it does.  Otherwise it
4081  * will return -ENOSPC.
4082  */
4083 static int may_commit_transaction(struct btrfs_root *root,
4084                                   struct btrfs_space_info *space_info,
4085                                   u64 bytes, int force)
4086 {
4087         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4088         struct btrfs_trans_handle *trans;
4089
4090         trans = (struct btrfs_trans_handle *)current->journal_info;
4091         if (trans)
4092                 return -EAGAIN;
4093
4094         if (force)
4095                 goto commit;
4096
4097         /* See if there is enough pinned space to make this reservation */
4098         spin_lock(&space_info->lock);
4099         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4100                                    bytes) >= 0) {
4101                 spin_unlock(&space_info->lock);
4102                 goto commit;
4103         }
4104         spin_unlock(&space_info->lock);
4105
4106         /*
4107          * See if there is some space in the delayed insertion reservation for
4108          * this reservation.
4109          */
4110         if (space_info != delayed_rsv->space_info)
4111                 return -ENOSPC;
4112
4113         spin_lock(&space_info->lock);
4114         spin_lock(&delayed_rsv->lock);
4115         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4116                                    bytes - delayed_rsv->size) >= 0) {
4117                 spin_unlock(&delayed_rsv->lock);
4118                 spin_unlock(&space_info->lock);
4119                 return -ENOSPC;
4120         }
4121         spin_unlock(&delayed_rsv->lock);
4122         spin_unlock(&space_info->lock);
4123
4124 commit:
4125         trans = btrfs_join_transaction(root);
4126         if (IS_ERR(trans))
4127                 return -ENOSPC;
4128
4129         return btrfs_commit_transaction(trans, root);
4130 }
4131
4132 enum flush_state {
4133         FLUSH_DELAYED_ITEMS_NR  =       1,
4134         FLUSH_DELAYED_ITEMS     =       2,
4135         FLUSH_DELALLOC          =       3,
4136         FLUSH_DELALLOC_WAIT     =       4,
4137         ALLOC_CHUNK             =       5,
4138         COMMIT_TRANS            =       6,
4139 };
4140
4141 static int flush_space(struct btrfs_root *root,
4142                        struct btrfs_space_info *space_info, u64 num_bytes,
4143                        u64 orig_bytes, int state)
4144 {
4145         struct btrfs_trans_handle *trans;
4146         int nr;
4147         int ret = 0;
4148
4149         switch (state) {
4150         case FLUSH_DELAYED_ITEMS_NR:
4151         case FLUSH_DELAYED_ITEMS:
4152                 if (state == FLUSH_DELAYED_ITEMS_NR) {
4153                         u64 bytes = btrfs_calc_trans_metadata_size(root, 1);
4154
4155                         nr = (int)div64_u64(num_bytes, bytes);
4156                         if (!nr)
4157                                 nr = 1;
4158                         nr *= 2;
4159                 } else {
4160                         nr = -1;
4161                 }
4162                 trans = btrfs_join_transaction(root);
4163                 if (IS_ERR(trans)) {
4164                         ret = PTR_ERR(trans);
4165                         break;
4166                 }
4167                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4168                 btrfs_end_transaction(trans, root);
4169                 break;
4170         case FLUSH_DELALLOC:
4171         case FLUSH_DELALLOC_WAIT:
4172                 shrink_delalloc(root, num_bytes, orig_bytes,
4173                                 state == FLUSH_DELALLOC_WAIT);
4174                 break;
4175         case ALLOC_CHUNK:
4176                 trans = btrfs_join_transaction(root);
4177                 if (IS_ERR(trans)) {
4178                         ret = PTR_ERR(trans);
4179                         break;
4180                 }
4181                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4182                                      btrfs_get_alloc_profile(root, 0),
4183                                      CHUNK_ALLOC_NO_FORCE);
4184                 btrfs_end_transaction(trans, root);
4185                 if (ret == -ENOSPC)
4186                         ret = 0;
4187                 break;
4188         case COMMIT_TRANS:
4189                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4190                 break;
4191         default:
4192                 ret = -ENOSPC;
4193                 break;
4194         }
4195
4196         return ret;
4197 }
4198 /**
4199  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4200  * @root - the root we're allocating for
4201  * @block_rsv - the block_rsv we're allocating for
4202  * @orig_bytes - the number of bytes we want
4203  * @flush - whether or not we can flush to make our reservation
4204  *
4205  * This will reserve orgi_bytes number of bytes from the space info associated
4206  * with the block_rsv.  If there is not enough space it will make an attempt to
4207  * flush out space to make room.  It will do this by flushing delalloc if
4208  * possible or committing the transaction.  If flush is 0 then no attempts to
4209  * regain reservations will be made and this will fail if there is not enough
4210  * space already.
4211  */
4212 static int reserve_metadata_bytes(struct btrfs_root *root,
4213                                   struct btrfs_block_rsv *block_rsv,
4214                                   u64 orig_bytes,
4215                                   enum btrfs_reserve_flush_enum flush)
4216 {
4217         struct btrfs_space_info *space_info = block_rsv->space_info;
4218         u64 used;
4219         u64 num_bytes = orig_bytes;
4220         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4221         int ret = 0;
4222         bool flushing = false;
4223
4224 again:
4225         ret = 0;
4226         spin_lock(&space_info->lock);
4227         /*
4228          * We only want to wait if somebody other than us is flushing and we
4229          * are actually allowed to flush all things.
4230          */
4231         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4232                space_info->flush) {
4233                 spin_unlock(&space_info->lock);
4234                 /*
4235                  * If we have a trans handle we can't wait because the flusher
4236                  * may have to commit the transaction, which would mean we would
4237                  * deadlock since we are waiting for the flusher to finish, but
4238                  * hold the current transaction open.
4239                  */
4240                 if (current->journal_info)
4241                         return -EAGAIN;
4242                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4243                 /* Must have been killed, return */
4244                 if (ret)
4245                         return -EINTR;
4246
4247                 spin_lock(&space_info->lock);
4248         }
4249
4250         ret = -ENOSPC;
4251         used = space_info->bytes_used + space_info->bytes_reserved +
4252                 space_info->bytes_pinned + space_info->bytes_readonly +
4253                 space_info->bytes_may_use;
4254
4255         /*
4256          * The idea here is that we've not already over-reserved the block group
4257          * then we can go ahead and save our reservation first and then start
4258          * flushing if we need to.  Otherwise if we've already overcommitted
4259          * lets start flushing stuff first and then come back and try to make
4260          * our reservation.
4261          */
4262         if (used <= space_info->total_bytes) {
4263                 if (used + orig_bytes <= space_info->total_bytes) {
4264                         space_info->bytes_may_use += orig_bytes;
4265                         trace_btrfs_space_reservation(root->fs_info,
4266                                 "space_info", space_info->flags, orig_bytes, 1);
4267                         ret = 0;
4268                 } else {
4269                         /*
4270                          * Ok set num_bytes to orig_bytes since we aren't
4271                          * overocmmitted, this way we only try and reclaim what
4272                          * we need.
4273                          */
4274                         num_bytes = orig_bytes;
4275                 }
4276         } else {
4277                 /*
4278                  * Ok we're over committed, set num_bytes to the overcommitted
4279                  * amount plus the amount of bytes that we need for this
4280                  * reservation.
4281                  */
4282                 num_bytes = used - space_info->total_bytes +
4283                         (orig_bytes * 2);
4284         }
4285
4286         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4287                 space_info->bytes_may_use += orig_bytes;
4288                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4289                                               space_info->flags, orig_bytes,
4290                                               1);
4291                 ret = 0;
4292         }
4293
4294         /*
4295          * Couldn't make our reservation, save our place so while we're trying
4296          * to reclaim space we can actually use it instead of somebody else
4297          * stealing it from us.
4298          *
4299          * We make the other tasks wait for the flush only when we can flush
4300          * all things.
4301          */
4302         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4303                 flushing = true;
4304                 space_info->flush = 1;
4305         }
4306
4307         spin_unlock(&space_info->lock);
4308
4309         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4310                 goto out;
4311
4312         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4313                           flush_state);
4314         flush_state++;
4315
4316         /*
4317          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4318          * would happen. So skip delalloc flush.
4319          */
4320         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4321             (flush_state == FLUSH_DELALLOC ||
4322              flush_state == FLUSH_DELALLOC_WAIT))
4323                 flush_state = ALLOC_CHUNK;
4324
4325         if (!ret)
4326                 goto again;
4327         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4328                  flush_state < COMMIT_TRANS)
4329                 goto again;
4330         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4331                  flush_state <= COMMIT_TRANS)
4332                 goto again;
4333
4334 out:
4335         if (ret == -ENOSPC &&
4336             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4337                 struct btrfs_block_rsv *global_rsv =
4338                         &root->fs_info->global_block_rsv;
4339
4340                 if (block_rsv != global_rsv &&
4341                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4342                         ret = 0;
4343         }
4344         if (flushing) {
4345                 spin_lock(&space_info->lock);
4346                 space_info->flush = 0;
4347                 wake_up_all(&space_info->wait);
4348                 spin_unlock(&space_info->lock);
4349         }
4350         return ret;
4351 }
4352
4353 static struct btrfs_block_rsv *get_block_rsv(
4354                                         const struct btrfs_trans_handle *trans,
4355                                         const struct btrfs_root *root)
4356 {
4357         struct btrfs_block_rsv *block_rsv = NULL;
4358
4359         if (root->ref_cows)
4360                 block_rsv = trans->block_rsv;
4361
4362         if (root == root->fs_info->csum_root && trans->adding_csums)
4363                 block_rsv = trans->block_rsv;
4364
4365         if (root == root->fs_info->uuid_root)
4366                 block_rsv = trans->block_rsv;
4367
4368         if (!block_rsv)
4369                 block_rsv = root->block_rsv;
4370
4371         if (!block_rsv)
4372                 block_rsv = &root->fs_info->empty_block_rsv;
4373
4374         return block_rsv;
4375 }
4376
4377 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4378                                u64 num_bytes)
4379 {
4380         int ret = -ENOSPC;
4381         spin_lock(&block_rsv->lock);
4382         if (block_rsv->reserved >= num_bytes) {
4383                 block_rsv->reserved -= num_bytes;
4384                 if (block_rsv->reserved < block_rsv->size)
4385                         block_rsv->full = 0;
4386                 ret = 0;
4387         }
4388         spin_unlock(&block_rsv->lock);
4389         return ret;
4390 }
4391
4392 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4393                                 u64 num_bytes, int update_size)
4394 {
4395         spin_lock(&block_rsv->lock);
4396         block_rsv->reserved += num_bytes;
4397         if (update_size)
4398                 block_rsv->size += num_bytes;
4399         else if (block_rsv->reserved >= block_rsv->size)
4400                 block_rsv->full = 1;
4401         spin_unlock(&block_rsv->lock);
4402 }
4403
4404 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4405                              struct btrfs_block_rsv *dest, u64 num_bytes,
4406                              int min_factor)
4407 {
4408         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4409         u64 min_bytes;
4410
4411         if (global_rsv->space_info != dest->space_info)
4412                 return -ENOSPC;
4413
4414         spin_lock(&global_rsv->lock);
4415         min_bytes = div_factor(global_rsv->size, min_factor);
4416         if (global_rsv->reserved < min_bytes + num_bytes) {
4417                 spin_unlock(&global_rsv->lock);
4418                 return -ENOSPC;
4419         }
4420         global_rsv->reserved -= num_bytes;
4421         if (global_rsv->reserved < global_rsv->size)
4422                 global_rsv->full = 0;
4423         spin_unlock(&global_rsv->lock);
4424
4425         block_rsv_add_bytes(dest, num_bytes, 1);
4426         return 0;
4427 }
4428
4429 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4430                                     struct btrfs_block_rsv *block_rsv,
4431                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4432 {
4433         struct btrfs_space_info *space_info = block_rsv->space_info;
4434
4435         spin_lock(&block_rsv->lock);
4436         if (num_bytes == (u64)-1)
4437                 num_bytes = block_rsv->size;
4438         block_rsv->size -= num_bytes;
4439         if (block_rsv->reserved >= block_rsv->size) {
4440                 num_bytes = block_rsv->reserved - block_rsv->size;
4441                 block_rsv->reserved = block_rsv->size;
4442                 block_rsv->full = 1;
4443         } else {
4444                 num_bytes = 0;
4445         }
4446         spin_unlock(&block_rsv->lock);
4447
4448         if (num_bytes > 0) {
4449                 if (dest) {
4450                         spin_lock(&dest->lock);
4451                         if (!dest->full) {
4452                                 u64 bytes_to_add;
4453
4454                                 bytes_to_add = dest->size - dest->reserved;
4455                                 bytes_to_add = min(num_bytes, bytes_to_add);
4456                                 dest->reserved += bytes_to_add;
4457                                 if (dest->reserved >= dest->size)
4458                                         dest->full = 1;
4459                                 num_bytes -= bytes_to_add;
4460                         }
4461                         spin_unlock(&dest->lock);
4462                 }
4463                 if (num_bytes) {
4464                         spin_lock(&space_info->lock);
4465                         space_info->bytes_may_use -= num_bytes;
4466                         trace_btrfs_space_reservation(fs_info, "space_info",
4467                                         space_info->flags, num_bytes, 0);
4468                         space_info->reservation_progress++;
4469                         spin_unlock(&space_info->lock);
4470                 }
4471         }
4472 }
4473
4474 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4475                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4476 {
4477         int ret;
4478
4479         ret = block_rsv_use_bytes(src, num_bytes);
4480         if (ret)
4481                 return ret;
4482
4483         block_rsv_add_bytes(dst, num_bytes, 1);
4484         return 0;
4485 }
4486
4487 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4488 {
4489         memset(rsv, 0, sizeof(*rsv));
4490         spin_lock_init(&rsv->lock);
4491         rsv->type = type;
4492 }
4493
4494 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4495                                               unsigned short type)
4496 {
4497         struct btrfs_block_rsv *block_rsv;
4498         struct btrfs_fs_info *fs_info = root->fs_info;
4499
4500         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4501         if (!block_rsv)
4502                 return NULL;
4503
4504         btrfs_init_block_rsv(block_rsv, type);
4505         block_rsv->space_info = __find_space_info(fs_info,
4506                                                   BTRFS_BLOCK_GROUP_METADATA);
4507         return block_rsv;
4508 }
4509
4510 void btrfs_free_block_rsv(struct btrfs_root *root,
4511                           struct btrfs_block_rsv *rsv)
4512 {
4513         if (!rsv)
4514                 return;
4515         btrfs_block_rsv_release(root, rsv, (u64)-1);
4516         kfree(rsv);
4517 }
4518
4519 int btrfs_block_rsv_add(struct btrfs_root *root,
4520                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4521                         enum btrfs_reserve_flush_enum flush)
4522 {
4523         int ret;
4524
4525         if (num_bytes == 0)
4526                 return 0;
4527
4528         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4529         if (!ret) {
4530                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4531                 return 0;
4532         }
4533
4534         return ret;
4535 }
4536
4537 int btrfs_block_rsv_check(struct btrfs_root *root,
4538                           struct btrfs_block_rsv *block_rsv, int min_factor)
4539 {
4540         u64 num_bytes = 0;
4541         int ret = -ENOSPC;
4542
4543         if (!block_rsv)
4544                 return 0;
4545
4546         spin_lock(&block_rsv->lock);
4547         num_bytes = div_factor(block_rsv->size, min_factor);
4548         if (block_rsv->reserved >= num_bytes)
4549                 ret = 0;
4550         spin_unlock(&block_rsv->lock);
4551
4552         return ret;
4553 }
4554
4555 int btrfs_block_rsv_refill(struct btrfs_root *root,
4556                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4557                            enum btrfs_reserve_flush_enum flush)
4558 {
4559         u64 num_bytes = 0;
4560         int ret = -ENOSPC;
4561
4562         if (!block_rsv)
4563                 return 0;
4564
4565         spin_lock(&block_rsv->lock);
4566         num_bytes = min_reserved;
4567         if (block_rsv->reserved >= num_bytes)
4568                 ret = 0;
4569         else
4570                 num_bytes -= block_rsv->reserved;
4571         spin_unlock(&block_rsv->lock);
4572
4573         if (!ret)
4574                 return 0;
4575
4576         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4577         if (!ret) {
4578                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4579                 return 0;
4580         }
4581
4582         return ret;
4583 }
4584
4585 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4586                             struct btrfs_block_rsv *dst_rsv,
4587                             u64 num_bytes)
4588 {
4589         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4590 }
4591
4592 void btrfs_block_rsv_release(struct btrfs_root *root,
4593                              struct btrfs_block_rsv *block_rsv,
4594                              u64 num_bytes)
4595 {
4596         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4597         if (global_rsv->full || global_rsv == block_rsv ||
4598             block_rsv->space_info != global_rsv->space_info)
4599                 global_rsv = NULL;
4600         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4601                                 num_bytes);
4602 }
4603
4604 /*
4605  * helper to calculate size of global block reservation.
4606  * the desired value is sum of space used by extent tree,
4607  * checksum tree and root tree
4608  */
4609 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4610 {
4611         struct btrfs_space_info *sinfo;
4612         u64 num_bytes;
4613         u64 meta_used;
4614         u64 data_used;
4615         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4616
4617         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4618         spin_lock(&sinfo->lock);
4619         data_used = sinfo->bytes_used;
4620         spin_unlock(&sinfo->lock);
4621
4622         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4623         spin_lock(&sinfo->lock);
4624         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4625                 data_used = 0;
4626         meta_used = sinfo->bytes_used;
4627         spin_unlock(&sinfo->lock);
4628
4629         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4630                     csum_size * 2;
4631         num_bytes += div64_u64(data_used + meta_used, 50);
4632
4633         if (num_bytes * 3 > meta_used)
4634                 num_bytes = div64_u64(meta_used, 3);
4635
4636         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4637 }
4638
4639 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4640 {
4641         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4642         struct btrfs_space_info *sinfo = block_rsv->space_info;
4643         u64 num_bytes;
4644
4645         num_bytes = calc_global_metadata_size(fs_info);
4646
4647         spin_lock(&sinfo->lock);
4648         spin_lock(&block_rsv->lock);
4649
4650         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4651
4652         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4653                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4654                     sinfo->bytes_may_use;
4655
4656         if (sinfo->total_bytes > num_bytes) {
4657                 num_bytes = sinfo->total_bytes - num_bytes;
4658                 block_rsv->reserved += num_bytes;
4659                 sinfo->bytes_may_use += num_bytes;
4660                 trace_btrfs_space_reservation(fs_info, "space_info",
4661                                       sinfo->flags, num_bytes, 1);
4662         }
4663
4664         if (block_rsv->reserved >= block_rsv->size) {
4665                 num_bytes = block_rsv->reserved - block_rsv->size;
4666                 sinfo->bytes_may_use -= num_bytes;
4667                 trace_btrfs_space_reservation(fs_info, "space_info",
4668                                       sinfo->flags, num_bytes, 0);
4669                 sinfo->reservation_progress++;
4670                 block_rsv->reserved = block_rsv->size;
4671                 block_rsv->full = 1;
4672         }
4673
4674         spin_unlock(&block_rsv->lock);
4675         spin_unlock(&sinfo->lock);
4676 }
4677
4678 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4679 {
4680         struct btrfs_space_info *space_info;
4681
4682         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4683         fs_info->chunk_block_rsv.space_info = space_info;
4684
4685         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4686         fs_info->global_block_rsv.space_info = space_info;
4687         fs_info->delalloc_block_rsv.space_info = space_info;
4688         fs_info->trans_block_rsv.space_info = space_info;
4689         fs_info->empty_block_rsv.space_info = space_info;
4690         fs_info->delayed_block_rsv.space_info = space_info;
4691
4692         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4693         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4694         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4695         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4696         if (fs_info->quota_root)
4697                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4698         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4699
4700         update_global_block_rsv(fs_info);
4701 }
4702
4703 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4704 {
4705         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4706                                 (u64)-1);
4707         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4708         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4709         WARN_ON(fs_info->trans_block_rsv.size > 0);
4710         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4711         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4712         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4713         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4714         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4715 }
4716
4717 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4718                                   struct btrfs_root *root)
4719 {
4720         if (!trans->block_rsv)
4721                 return;
4722
4723         if (!trans->bytes_reserved)
4724                 return;
4725
4726         trace_btrfs_space_reservation(root->fs_info, "transaction",
4727                                       trans->transid, trans->bytes_reserved, 0);
4728         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4729         trans->bytes_reserved = 0;
4730 }
4731
4732 /* Can only return 0 or -ENOSPC */
4733 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4734                                   struct inode *inode)
4735 {
4736         struct btrfs_root *root = BTRFS_I(inode)->root;
4737         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4738         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4739
4740         /*
4741          * We need to hold space in order to delete our orphan item once we've
4742          * added it, so this takes the reservation so we can release it later
4743          * when we are truly done with the orphan item.
4744          */
4745         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4746         trace_btrfs_space_reservation(root->fs_info, "orphan",
4747                                       btrfs_ino(inode), num_bytes, 1);
4748         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4749 }
4750
4751 void btrfs_orphan_release_metadata(struct inode *inode)
4752 {
4753         struct btrfs_root *root = BTRFS_I(inode)->root;
4754         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4755         trace_btrfs_space_reservation(root->fs_info, "orphan",
4756                                       btrfs_ino(inode), num_bytes, 0);
4757         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4758 }
4759
4760 /*
4761  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4762  * root: the root of the parent directory
4763  * rsv: block reservation
4764  * items: the number of items that we need do reservation
4765  * qgroup_reserved: used to return the reserved size in qgroup
4766  *
4767  * This function is used to reserve the space for snapshot/subvolume
4768  * creation and deletion. Those operations are different with the
4769  * common file/directory operations, they change two fs/file trees
4770  * and root tree, the number of items that the qgroup reserves is
4771  * different with the free space reservation. So we can not use
4772  * the space reseravtion mechanism in start_transaction().
4773  */
4774 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4775                                      struct btrfs_block_rsv *rsv,
4776                                      int items,
4777                                      u64 *qgroup_reserved,
4778                                      bool use_global_rsv)
4779 {
4780         u64 num_bytes;
4781         int ret;
4782         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4783
4784         if (root->fs_info->quota_enabled) {
4785                 /* One for parent inode, two for dir entries */
4786                 num_bytes = 3 * root->leafsize;
4787                 ret = btrfs_qgroup_reserve(root, num_bytes);
4788                 if (ret)
4789                         return ret;
4790         } else {
4791                 num_bytes = 0;
4792         }
4793
4794         *qgroup_reserved = num_bytes;
4795
4796         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4797         rsv->space_info = __find_space_info(root->fs_info,
4798                                             BTRFS_BLOCK_GROUP_METADATA);
4799         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4800                                   BTRFS_RESERVE_FLUSH_ALL);
4801
4802         if (ret == -ENOSPC && use_global_rsv)
4803                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
4804
4805         if (ret) {
4806                 if (*qgroup_reserved)
4807                         btrfs_qgroup_free(root, *qgroup_reserved);
4808         }
4809
4810         return ret;
4811 }
4812
4813 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4814                                       struct btrfs_block_rsv *rsv,
4815                                       u64 qgroup_reserved)
4816 {
4817         btrfs_block_rsv_release(root, rsv, (u64)-1);
4818         if (qgroup_reserved)
4819                 btrfs_qgroup_free(root, qgroup_reserved);
4820 }
4821
4822 /**
4823  * drop_outstanding_extent - drop an outstanding extent
4824  * @inode: the inode we're dropping the extent for
4825  *
4826  * This is called when we are freeing up an outstanding extent, either called
4827  * after an error or after an extent is written.  This will return the number of
4828  * reserved extents that need to be freed.  This must be called with
4829  * BTRFS_I(inode)->lock held.
4830  */
4831 static unsigned drop_outstanding_extent(struct inode *inode)
4832 {
4833         unsigned drop_inode_space = 0;
4834         unsigned dropped_extents = 0;
4835
4836         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4837         BTRFS_I(inode)->outstanding_extents--;
4838
4839         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4840             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4841                                &BTRFS_I(inode)->runtime_flags))
4842                 drop_inode_space = 1;
4843
4844         /*
4845          * If we have more or the same amount of outsanding extents than we have
4846          * reserved then we need to leave the reserved extents count alone.
4847          */
4848         if (BTRFS_I(inode)->outstanding_extents >=
4849             BTRFS_I(inode)->reserved_extents)
4850                 return drop_inode_space;
4851
4852         dropped_extents = BTRFS_I(inode)->reserved_extents -
4853                 BTRFS_I(inode)->outstanding_extents;
4854         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4855         return dropped_extents + drop_inode_space;
4856 }
4857
4858 /**
4859  * calc_csum_metadata_size - return the amount of metada space that must be
4860  *      reserved/free'd for the given bytes.
4861  * @inode: the inode we're manipulating
4862  * @num_bytes: the number of bytes in question
4863  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4864  *
4865  * This adjusts the number of csum_bytes in the inode and then returns the
4866  * correct amount of metadata that must either be reserved or freed.  We
4867  * calculate how many checksums we can fit into one leaf and then divide the
4868  * number of bytes that will need to be checksumed by this value to figure out
4869  * how many checksums will be required.  If we are adding bytes then the number
4870  * may go up and we will return the number of additional bytes that must be
4871  * reserved.  If it is going down we will return the number of bytes that must
4872  * be freed.
4873  *
4874  * This must be called with BTRFS_I(inode)->lock held.
4875  */
4876 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4877                                    int reserve)
4878 {
4879         struct btrfs_root *root = BTRFS_I(inode)->root;
4880         u64 csum_size;
4881         int num_csums_per_leaf;
4882         int num_csums;
4883         int old_csums;
4884
4885         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4886             BTRFS_I(inode)->csum_bytes == 0)
4887                 return 0;
4888
4889         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4890         if (reserve)
4891                 BTRFS_I(inode)->csum_bytes += num_bytes;
4892         else
4893                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4894         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4895         num_csums_per_leaf = (int)div64_u64(csum_size,
4896                                             sizeof(struct btrfs_csum_item) +
4897                                             sizeof(struct btrfs_disk_key));
4898         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4899         num_csums = num_csums + num_csums_per_leaf - 1;
4900         num_csums = num_csums / num_csums_per_leaf;
4901
4902         old_csums = old_csums + num_csums_per_leaf - 1;
4903         old_csums = old_csums / num_csums_per_leaf;
4904
4905         /* No change, no need to reserve more */
4906         if (old_csums == num_csums)
4907                 return 0;
4908
4909         if (reserve)
4910                 return btrfs_calc_trans_metadata_size(root,
4911                                                       num_csums - old_csums);
4912
4913         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4914 }
4915
4916 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4917 {
4918         struct btrfs_root *root = BTRFS_I(inode)->root;
4919         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4920         u64 to_reserve = 0;
4921         u64 csum_bytes;
4922         unsigned nr_extents = 0;
4923         int extra_reserve = 0;
4924         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
4925         int ret = 0;
4926         bool delalloc_lock = true;
4927         u64 to_free = 0;
4928         unsigned dropped;
4929
4930         /* If we are a free space inode we need to not flush since we will be in
4931          * the middle of a transaction commit.  We also don't need the delalloc
4932          * mutex since we won't race with anybody.  We need this mostly to make
4933          * lockdep shut its filthy mouth.
4934          */
4935         if (btrfs_is_free_space_inode(inode)) {
4936                 flush = BTRFS_RESERVE_NO_FLUSH;
4937                 delalloc_lock = false;
4938         }
4939
4940         if (flush != BTRFS_RESERVE_NO_FLUSH &&
4941             btrfs_transaction_in_commit(root->fs_info))
4942                 schedule_timeout(1);
4943
4944         if (delalloc_lock)
4945                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4946
4947         num_bytes = ALIGN(num_bytes, root->sectorsize);
4948
4949         spin_lock(&BTRFS_I(inode)->lock);
4950         BTRFS_I(inode)->outstanding_extents++;
4951
4952         if (BTRFS_I(inode)->outstanding_extents >
4953             BTRFS_I(inode)->reserved_extents)
4954                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4955                         BTRFS_I(inode)->reserved_extents;
4956
4957         /*
4958          * Add an item to reserve for updating the inode when we complete the
4959          * delalloc io.
4960          */
4961         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4962                       &BTRFS_I(inode)->runtime_flags)) {
4963                 nr_extents++;
4964                 extra_reserve = 1;
4965         }
4966
4967         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4968         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4969         csum_bytes = BTRFS_I(inode)->csum_bytes;
4970         spin_unlock(&BTRFS_I(inode)->lock);
4971
4972         if (root->fs_info->quota_enabled) {
4973                 ret = btrfs_qgroup_reserve(root, num_bytes +
4974                                            nr_extents * root->leafsize);
4975                 if (ret)
4976                         goto out_fail;
4977         }
4978
4979         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4980         if (unlikely(ret)) {
4981                 if (root->fs_info->quota_enabled)
4982                         btrfs_qgroup_free(root, num_bytes +
4983                                                 nr_extents * root->leafsize);
4984                 goto out_fail;
4985         }
4986
4987         spin_lock(&BTRFS_I(inode)->lock);
4988         if (extra_reserve) {
4989                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4990                         &BTRFS_I(inode)->runtime_flags);
4991                 nr_extents--;
4992         }
4993         BTRFS_I(inode)->reserved_extents += nr_extents;
4994         spin_unlock(&BTRFS_I(inode)->lock);
4995
4996         if (delalloc_lock)
4997                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4998
4999         if (to_reserve)
5000                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
5001                                               btrfs_ino(inode), to_reserve, 1);
5002         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5003
5004         return 0;
5005
5006 out_fail:
5007         spin_lock(&BTRFS_I(inode)->lock);
5008         dropped = drop_outstanding_extent(inode);
5009         /*
5010          * If the inodes csum_bytes is the same as the original
5011          * csum_bytes then we know we haven't raced with any free()ers
5012          * so we can just reduce our inodes csum bytes and carry on.
5013          */
5014         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5015                 calc_csum_metadata_size(inode, num_bytes, 0);
5016         } else {
5017                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5018                 u64 bytes;
5019
5020                 /*
5021                  * This is tricky, but first we need to figure out how much we
5022                  * free'd from any free-ers that occured during this
5023                  * reservation, so we reset ->csum_bytes to the csum_bytes
5024                  * before we dropped our lock, and then call the free for the
5025                  * number of bytes that were freed while we were trying our
5026                  * reservation.
5027                  */
5028                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5029                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5030                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5031
5032
5033                 /*
5034                  * Now we need to see how much we would have freed had we not
5035                  * been making this reservation and our ->csum_bytes were not
5036                  * artificially inflated.
5037                  */
5038                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5039                 bytes = csum_bytes - orig_csum_bytes;
5040                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5041
5042                 /*
5043                  * Now reset ->csum_bytes to what it should be.  If bytes is
5044                  * more than to_free then we would have free'd more space had we
5045                  * not had an artificially high ->csum_bytes, so we need to free
5046                  * the remainder.  If bytes is the same or less then we don't
5047                  * need to do anything, the other free-ers did the correct
5048                  * thing.
5049                  */
5050                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5051                 if (bytes > to_free)
5052                         to_free = bytes - to_free;
5053                 else
5054                         to_free = 0;
5055         }
5056         spin_unlock(&BTRFS_I(inode)->lock);
5057         if (dropped)
5058                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5059
5060         if (to_free) {
5061                 btrfs_block_rsv_release(root, block_rsv, to_free);
5062                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5063                                               btrfs_ino(inode), to_free, 0);
5064         }
5065         if (delalloc_lock)
5066                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5067         return ret;
5068 }
5069
5070 /**
5071  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5072  * @inode: the inode to release the reservation for
5073  * @num_bytes: the number of bytes we're releasing
5074  *
5075  * This will release the metadata reservation for an inode.  This can be called
5076  * once we complete IO for a given set of bytes to release their metadata
5077  * reservations.
5078  */
5079 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5080 {
5081         struct btrfs_root *root = BTRFS_I(inode)->root;
5082         u64 to_free = 0;
5083         unsigned dropped;
5084
5085         num_bytes = ALIGN(num_bytes, root->sectorsize);
5086         spin_lock(&BTRFS_I(inode)->lock);
5087         dropped = drop_outstanding_extent(inode);
5088
5089         if (num_bytes)
5090                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5091         spin_unlock(&BTRFS_I(inode)->lock);
5092         if (dropped > 0)
5093                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5094
5095         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5096                                       btrfs_ino(inode), to_free, 0);
5097         if (root->fs_info->quota_enabled) {
5098                 btrfs_qgroup_free(root, num_bytes +
5099                                         dropped * root->leafsize);
5100         }
5101
5102         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5103                                 to_free);
5104 }
5105
5106 /**
5107  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5108  * @inode: inode we're writing to
5109  * @num_bytes: the number of bytes we want to allocate
5110  *
5111  * This will do the following things
5112  *
5113  * o reserve space in the data space info for num_bytes
5114  * o reserve space in the metadata space info based on number of outstanding
5115  *   extents and how much csums will be needed
5116  * o add to the inodes ->delalloc_bytes
5117  * o add it to the fs_info's delalloc inodes list.
5118  *
5119  * This will return 0 for success and -ENOSPC if there is no space left.
5120  */
5121 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5122 {
5123         int ret;
5124
5125         ret = btrfs_check_data_free_space(inode, num_bytes);
5126         if (ret)
5127                 return ret;
5128
5129         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5130         if (ret) {
5131                 btrfs_free_reserved_data_space(inode, num_bytes);
5132                 return ret;
5133         }
5134
5135         return 0;
5136 }
5137
5138 /**
5139  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5140  * @inode: inode we're releasing space for
5141  * @num_bytes: the number of bytes we want to free up
5142  *
5143  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5144  * called in the case that we don't need the metadata AND data reservations
5145  * anymore.  So if there is an error or we insert an inline extent.
5146  *
5147  * This function will release the metadata space that was not used and will
5148  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5149  * list if there are no delalloc bytes left.
5150  */
5151 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5152 {
5153         btrfs_delalloc_release_metadata(inode, num_bytes);
5154         btrfs_free_reserved_data_space(inode, num_bytes);
5155 }
5156
5157 static int update_block_group(struct btrfs_root *root,
5158                               u64 bytenr, u64 num_bytes, int alloc)
5159 {
5160         struct btrfs_block_group_cache *cache = NULL;
5161         struct btrfs_fs_info *info = root->fs_info;
5162         u64 total = num_bytes;
5163         u64 old_val;
5164         u64 byte_in_group;
5165         int factor;
5166
5167         /* block accounting for super block */
5168         spin_lock(&info->delalloc_root_lock);
5169         old_val = btrfs_super_bytes_used(info->super_copy);
5170         if (alloc)
5171                 old_val += num_bytes;
5172         else
5173                 old_val -= num_bytes;
5174         btrfs_set_super_bytes_used(info->super_copy, old_val);
5175         spin_unlock(&info->delalloc_root_lock);
5176
5177         while (total) {
5178                 cache = btrfs_lookup_block_group(info, bytenr);
5179                 if (!cache)
5180                         return -ENOENT;
5181                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5182                                     BTRFS_BLOCK_GROUP_RAID1 |
5183                                     BTRFS_BLOCK_GROUP_RAID10))
5184                         factor = 2;
5185                 else
5186                         factor = 1;
5187                 /*
5188                  * If this block group has free space cache written out, we
5189                  * need to make sure to load it if we are removing space.  This
5190                  * is because we need the unpinning stage to actually add the
5191                  * space back to the block group, otherwise we will leak space.
5192                  */
5193                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5194                         cache_block_group(cache, 1);
5195
5196                 byte_in_group = bytenr - cache->key.objectid;
5197                 WARN_ON(byte_in_group > cache->key.offset);
5198
5199                 spin_lock(&cache->space_info->lock);
5200                 spin_lock(&cache->lock);
5201
5202                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5203                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5204                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5205
5206                 cache->dirty = 1;
5207                 old_val = btrfs_block_group_used(&cache->item);
5208                 num_bytes = min(total, cache->key.offset - byte_in_group);
5209                 if (alloc) {
5210                         old_val += num_bytes;
5211                         btrfs_set_block_group_used(&cache->item, old_val);
5212                         cache->reserved -= num_bytes;
5213                         cache->space_info->bytes_reserved -= num_bytes;
5214                         cache->space_info->bytes_used += num_bytes;
5215                         cache->space_info->disk_used += num_bytes * factor;
5216                         spin_unlock(&cache->lock);
5217                         spin_unlock(&cache->space_info->lock);
5218                 } else {
5219                         old_val -= num_bytes;
5220                         btrfs_set_block_group_used(&cache->item, old_val);
5221                         cache->pinned += num_bytes;
5222                         cache->space_info->bytes_pinned += num_bytes;
5223                         cache->space_info->bytes_used -= num_bytes;
5224                         cache->space_info->disk_used -= num_bytes * factor;
5225                         spin_unlock(&cache->lock);
5226                         spin_unlock(&cache->space_info->lock);
5227
5228                         set_extent_dirty(info->pinned_extents,
5229                                          bytenr, bytenr + num_bytes - 1,
5230                                          GFP_NOFS | __GFP_NOFAIL);
5231                 }
5232                 btrfs_put_block_group(cache);
5233                 total -= num_bytes;
5234                 bytenr += num_bytes;
5235         }
5236         return 0;
5237 }
5238
5239 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5240 {
5241         struct btrfs_block_group_cache *cache;
5242         u64 bytenr;
5243
5244         spin_lock(&root->fs_info->block_group_cache_lock);
5245         bytenr = root->fs_info->first_logical_byte;
5246         spin_unlock(&root->fs_info->block_group_cache_lock);
5247
5248         if (bytenr < (u64)-1)
5249                 return bytenr;
5250
5251         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5252         if (!cache)
5253                 return 0;
5254
5255         bytenr = cache->key.objectid;
5256         btrfs_put_block_group(cache);
5257
5258         return bytenr;
5259 }
5260
5261 static int pin_down_extent(struct btrfs_root *root,
5262                            struct btrfs_block_group_cache *cache,
5263                            u64 bytenr, u64 num_bytes, int reserved)
5264 {
5265         spin_lock(&cache->space_info->lock);
5266         spin_lock(&cache->lock);
5267         cache->pinned += num_bytes;
5268         cache->space_info->bytes_pinned += num_bytes;
5269         if (reserved) {
5270                 cache->reserved -= num_bytes;
5271                 cache->space_info->bytes_reserved -= num_bytes;
5272         }
5273         spin_unlock(&cache->lock);
5274         spin_unlock(&cache->space_info->lock);
5275
5276         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5277                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5278         return 0;
5279 }
5280
5281 /*
5282  * this function must be called within transaction
5283  */
5284 int btrfs_pin_extent(struct btrfs_root *root,
5285                      u64 bytenr, u64 num_bytes, int reserved)
5286 {
5287         struct btrfs_block_group_cache *cache;
5288
5289         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5290         BUG_ON(!cache); /* Logic error */
5291
5292         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5293
5294         btrfs_put_block_group(cache);
5295         return 0;
5296 }
5297
5298 /*
5299  * this function must be called within transaction
5300  */
5301 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5302                                     u64 bytenr, u64 num_bytes)
5303 {
5304         struct btrfs_block_group_cache *cache;
5305         int ret;
5306
5307         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5308         if (!cache)
5309                 return -EINVAL;
5310
5311         /*
5312          * pull in the free space cache (if any) so that our pin
5313          * removes the free space from the cache.  We have load_only set
5314          * to one because the slow code to read in the free extents does check
5315          * the pinned extents.
5316          */
5317         cache_block_group(cache, 1);
5318
5319         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5320
5321         /* remove us from the free space cache (if we're there at all) */
5322         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5323         btrfs_put_block_group(cache);
5324         return ret;
5325 }
5326
5327 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5328 {
5329         int ret;
5330         struct btrfs_block_group_cache *block_group;
5331         struct btrfs_caching_control *caching_ctl;
5332
5333         block_group = btrfs_lookup_block_group(root->fs_info, start);
5334         if (!block_group)
5335                 return -EINVAL;
5336
5337         cache_block_group(block_group, 0);
5338         caching_ctl = get_caching_control(block_group);
5339
5340         if (!caching_ctl) {
5341                 /* Logic error */
5342                 BUG_ON(!block_group_cache_done(block_group));
5343                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5344         } else {
5345                 mutex_lock(&caching_ctl->mutex);
5346
5347                 if (start >= caching_ctl->progress) {
5348                         ret = add_excluded_extent(root, start, num_bytes);
5349                 } else if (start + num_bytes <= caching_ctl->progress) {
5350                         ret = btrfs_remove_free_space(block_group,
5351                                                       start, num_bytes);
5352                 } else {
5353                         num_bytes = caching_ctl->progress - start;
5354                         ret = btrfs_remove_free_space(block_group,
5355                                                       start, num_bytes);
5356                         if (ret)
5357                                 goto out_lock;
5358
5359                         num_bytes = (start + num_bytes) -
5360                                 caching_ctl->progress;
5361                         start = caching_ctl->progress;
5362                         ret = add_excluded_extent(root, start, num_bytes);
5363                 }
5364 out_lock:
5365                 mutex_unlock(&caching_ctl->mutex);
5366                 put_caching_control(caching_ctl);
5367         }
5368         btrfs_put_block_group(block_group);
5369         return ret;
5370 }
5371
5372 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5373                                  struct extent_buffer *eb)
5374 {
5375         struct btrfs_file_extent_item *item;
5376         struct btrfs_key key;
5377         int found_type;
5378         int i;
5379
5380         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5381                 return 0;
5382
5383         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5384                 btrfs_item_key_to_cpu(eb, &key, i);
5385                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5386                         continue;
5387                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5388                 found_type = btrfs_file_extent_type(eb, item);
5389                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5390                         continue;
5391                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5392                         continue;
5393                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5394                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5395                 __exclude_logged_extent(log, key.objectid, key.offset);
5396         }
5397
5398         return 0;
5399 }
5400
5401 /**
5402  * btrfs_update_reserved_bytes - update the block_group and space info counters
5403  * @cache:      The cache we are manipulating
5404  * @num_bytes:  The number of bytes in question
5405  * @reserve:    One of the reservation enums
5406  *
5407  * This is called by the allocator when it reserves space, or by somebody who is
5408  * freeing space that was never actually used on disk.  For example if you
5409  * reserve some space for a new leaf in transaction A and before transaction A
5410  * commits you free that leaf, you call this with reserve set to 0 in order to
5411  * clear the reservation.
5412  *
5413  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5414  * ENOSPC accounting.  For data we handle the reservation through clearing the
5415  * delalloc bits in the io_tree.  We have to do this since we could end up
5416  * allocating less disk space for the amount of data we have reserved in the
5417  * case of compression.
5418  *
5419  * If this is a reservation and the block group has become read only we cannot
5420  * make the reservation and return -EAGAIN, otherwise this function always
5421  * succeeds.
5422  */
5423 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5424                                        u64 num_bytes, int reserve)
5425 {
5426         struct btrfs_space_info *space_info = cache->space_info;
5427         int ret = 0;
5428
5429         spin_lock(&space_info->lock);
5430         spin_lock(&cache->lock);
5431         if (reserve != RESERVE_FREE) {
5432                 if (cache->ro) {
5433                         ret = -EAGAIN;
5434                 } else {
5435                         cache->reserved += num_bytes;
5436                         space_info->bytes_reserved += num_bytes;
5437                         if (reserve == RESERVE_ALLOC) {
5438                                 trace_btrfs_space_reservation(cache->fs_info,
5439                                                 "space_info", space_info->flags,
5440                                                 num_bytes, 0);
5441                                 space_info->bytes_may_use -= num_bytes;
5442                         }
5443                 }
5444         } else {
5445                 if (cache->ro)
5446                         space_info->bytes_readonly += num_bytes;
5447                 cache->reserved -= num_bytes;
5448                 space_info->bytes_reserved -= num_bytes;
5449                 space_info->reservation_progress++;
5450         }
5451         spin_unlock(&cache->lock);
5452         spin_unlock(&space_info->lock);
5453         return ret;
5454 }
5455
5456 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5457                                 struct btrfs_root *root)
5458 {
5459         struct btrfs_fs_info *fs_info = root->fs_info;
5460         struct btrfs_caching_control *next;
5461         struct btrfs_caching_control *caching_ctl;
5462         struct btrfs_block_group_cache *cache;
5463         struct btrfs_space_info *space_info;
5464
5465         down_write(&fs_info->extent_commit_sem);
5466
5467         list_for_each_entry_safe(caching_ctl, next,
5468                                  &fs_info->caching_block_groups, list) {
5469                 cache = caching_ctl->block_group;
5470                 if (block_group_cache_done(cache)) {
5471                         cache->last_byte_to_unpin = (u64)-1;
5472                         list_del_init(&caching_ctl->list);
5473                         put_caching_control(caching_ctl);
5474                 } else {
5475                         cache->last_byte_to_unpin = caching_ctl->progress;
5476                 }
5477         }
5478
5479         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5480                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5481         else
5482                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5483
5484         up_write(&fs_info->extent_commit_sem);
5485
5486         list_for_each_entry_rcu(space_info, &fs_info->space_info, list)
5487                 percpu_counter_set(&space_info->total_bytes_pinned, 0);
5488
5489         update_global_block_rsv(fs_info);
5490 }
5491
5492 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5493 {
5494         struct btrfs_fs_info *fs_info = root->fs_info;
5495         struct btrfs_block_group_cache *cache = NULL;
5496         struct btrfs_space_info *space_info;
5497         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5498         u64 len;
5499         bool readonly;
5500
5501         while (start <= end) {
5502                 readonly = false;
5503                 if (!cache ||
5504                     start >= cache->key.objectid + cache->key.offset) {
5505                         if (cache)
5506                                 btrfs_put_block_group(cache);
5507                         cache = btrfs_lookup_block_group(fs_info, start);
5508                         BUG_ON(!cache); /* Logic error */
5509                 }
5510
5511                 len = cache->key.objectid + cache->key.offset - start;
5512                 len = min(len, end + 1 - start);
5513
5514                 if (start < cache->last_byte_to_unpin) {
5515                         len = min(len, cache->last_byte_to_unpin - start);
5516                         btrfs_add_free_space(cache, start, len);
5517                 }
5518
5519                 start += len;
5520                 space_info = cache->space_info;
5521
5522                 spin_lock(&space_info->lock);
5523                 spin_lock(&cache->lock);
5524                 cache->pinned -= len;
5525                 space_info->bytes_pinned -= len;
5526                 if (cache->ro) {
5527                         space_info->bytes_readonly += len;
5528                         readonly = true;
5529                 }
5530                 spin_unlock(&cache->lock);
5531                 if (!readonly && global_rsv->space_info == space_info) {
5532                         spin_lock(&global_rsv->lock);
5533                         if (!global_rsv->full) {
5534                                 len = min(len, global_rsv->size -
5535                                           global_rsv->reserved);
5536                                 global_rsv->reserved += len;
5537                                 space_info->bytes_may_use += len;
5538                                 if (global_rsv->reserved >= global_rsv->size)
5539                                         global_rsv->full = 1;
5540                         }
5541                         spin_unlock(&global_rsv->lock);
5542                 }
5543                 spin_unlock(&space_info->lock);
5544         }
5545
5546         if (cache)
5547                 btrfs_put_block_group(cache);
5548         return 0;
5549 }
5550
5551 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5552                                struct btrfs_root *root)
5553 {
5554         struct btrfs_fs_info *fs_info = root->fs_info;
5555         struct extent_io_tree *unpin;
5556         u64 start;
5557         u64 end;
5558         int ret;
5559
5560         if (trans->aborted)
5561                 return 0;
5562
5563         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5564                 unpin = &fs_info->freed_extents[1];
5565         else
5566                 unpin = &fs_info->freed_extents[0];
5567
5568         while (1) {
5569                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5570                                             EXTENT_DIRTY, NULL);
5571                 if (ret)
5572                         break;
5573
5574                 if (btrfs_test_opt(root, DISCARD))
5575                         ret = btrfs_discard_extent(root, start,
5576                                                    end + 1 - start, NULL);
5577
5578                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5579                 unpin_extent_range(root, start, end);
5580                 cond_resched();
5581         }
5582
5583         return 0;
5584 }
5585
5586 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
5587                              u64 owner, u64 root_objectid)
5588 {
5589         struct btrfs_space_info *space_info;
5590         u64 flags;
5591
5592         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5593                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
5594                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
5595                 else
5596                         flags = BTRFS_BLOCK_GROUP_METADATA;
5597         } else {
5598                 flags = BTRFS_BLOCK_GROUP_DATA;
5599         }
5600
5601         space_info = __find_space_info(fs_info, flags);
5602         BUG_ON(!space_info); /* Logic bug */
5603         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
5604 }
5605
5606
5607 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5608                                 struct btrfs_root *root,
5609                                 u64 bytenr, u64 num_bytes, u64 parent,
5610                                 u64 root_objectid, u64 owner_objectid,
5611                                 u64 owner_offset, int refs_to_drop,
5612                                 struct btrfs_delayed_extent_op *extent_op)
5613 {
5614         struct btrfs_key key;
5615         struct btrfs_path *path;
5616         struct btrfs_fs_info *info = root->fs_info;
5617         struct btrfs_root *extent_root = info->extent_root;
5618         struct extent_buffer *leaf;
5619         struct btrfs_extent_item *ei;
5620         struct btrfs_extent_inline_ref *iref;
5621         int ret;
5622         int is_data;
5623         int extent_slot = 0;
5624         int found_extent = 0;
5625         int num_to_del = 1;
5626         u32 item_size;
5627         u64 refs;
5628         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5629                                                  SKINNY_METADATA);
5630
5631         path = btrfs_alloc_path();
5632         if (!path)
5633                 return -ENOMEM;
5634
5635         path->reada = 1;
5636         path->leave_spinning = 1;
5637
5638         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5639         BUG_ON(!is_data && refs_to_drop != 1);
5640
5641         if (is_data)
5642                 skinny_metadata = 0;
5643
5644         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5645                                     bytenr, num_bytes, parent,
5646                                     root_objectid, owner_objectid,
5647                                     owner_offset);
5648         if (ret == 0) {
5649                 extent_slot = path->slots[0];
5650                 while (extent_slot >= 0) {
5651                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5652                                               extent_slot);
5653                         if (key.objectid != bytenr)
5654                                 break;
5655                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5656                             key.offset == num_bytes) {
5657                                 found_extent = 1;
5658                                 break;
5659                         }
5660                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5661                             key.offset == owner_objectid) {
5662                                 found_extent = 1;
5663                                 break;
5664                         }
5665                         if (path->slots[0] - extent_slot > 5)
5666                                 break;
5667                         extent_slot--;
5668                 }
5669 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5670                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5671                 if (found_extent && item_size < sizeof(*ei))
5672                         found_extent = 0;
5673 #endif
5674                 if (!found_extent) {
5675                         BUG_ON(iref);
5676                         ret = remove_extent_backref(trans, extent_root, path,
5677                                                     NULL, refs_to_drop,
5678                                                     is_data);
5679                         if (ret) {
5680                                 btrfs_abort_transaction(trans, extent_root, ret);
5681                                 goto out;
5682                         }
5683                         btrfs_release_path(path);
5684                         path->leave_spinning = 1;
5685
5686                         key.objectid = bytenr;
5687                         key.type = BTRFS_EXTENT_ITEM_KEY;
5688                         key.offset = num_bytes;
5689
5690                         if (!is_data && skinny_metadata) {
5691                                 key.type = BTRFS_METADATA_ITEM_KEY;
5692                                 key.offset = owner_objectid;
5693                         }
5694
5695                         ret = btrfs_search_slot(trans, extent_root,
5696                                                 &key, path, -1, 1);
5697                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5698                                 /*
5699                                  * Couldn't find our skinny metadata item,
5700                                  * see if we have ye olde extent item.
5701                                  */
5702                                 path->slots[0]--;
5703                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5704                                                       path->slots[0]);
5705                                 if (key.objectid == bytenr &&
5706                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5707                                     key.offset == num_bytes)
5708                                         ret = 0;
5709                         }
5710
5711                         if (ret > 0 && skinny_metadata) {
5712                                 skinny_metadata = false;
5713                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5714                                 key.offset = num_bytes;
5715                                 btrfs_release_path(path);
5716                                 ret = btrfs_search_slot(trans, extent_root,
5717                                                         &key, path, -1, 1);
5718                         }
5719
5720                         if (ret) {
5721                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5722                                         ret, bytenr);
5723                                 if (ret > 0)
5724                                         btrfs_print_leaf(extent_root,
5725                                                          path->nodes[0]);
5726                         }
5727                         if (ret < 0) {
5728                                 btrfs_abort_transaction(trans, extent_root, ret);
5729                                 goto out;
5730                         }
5731                         extent_slot = path->slots[0];
5732                 }
5733         } else if (ret == -ENOENT) {
5734                 btrfs_print_leaf(extent_root, path->nodes[0]);
5735                 WARN_ON(1);
5736                 btrfs_err(info,
5737                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5738                         bytenr, parent, root_objectid, owner_objectid,
5739                         owner_offset);
5740         } else {
5741                 btrfs_abort_transaction(trans, extent_root, ret);
5742                 goto out;
5743         }
5744
5745         leaf = path->nodes[0];
5746         item_size = btrfs_item_size_nr(leaf, extent_slot);
5747 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5748         if (item_size < sizeof(*ei)) {
5749                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5750                 ret = convert_extent_item_v0(trans, extent_root, path,
5751                                              owner_objectid, 0);
5752                 if (ret < 0) {
5753                         btrfs_abort_transaction(trans, extent_root, ret);
5754                         goto out;
5755                 }
5756
5757                 btrfs_release_path(path);
5758                 path->leave_spinning = 1;
5759
5760                 key.objectid = bytenr;
5761                 key.type = BTRFS_EXTENT_ITEM_KEY;
5762                 key.offset = num_bytes;
5763
5764                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5765                                         -1, 1);
5766                 if (ret) {
5767                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5768                                 ret, bytenr);
5769                         btrfs_print_leaf(extent_root, path->nodes[0]);
5770                 }
5771                 if (ret < 0) {
5772                         btrfs_abort_transaction(trans, extent_root, ret);
5773                         goto out;
5774                 }
5775
5776                 extent_slot = path->slots[0];
5777                 leaf = path->nodes[0];
5778                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5779         }
5780 #endif
5781         BUG_ON(item_size < sizeof(*ei));
5782         ei = btrfs_item_ptr(leaf, extent_slot,
5783                             struct btrfs_extent_item);
5784         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
5785             key.type == BTRFS_EXTENT_ITEM_KEY) {
5786                 struct btrfs_tree_block_info *bi;
5787                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5788                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5789                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5790         }
5791
5792         refs = btrfs_extent_refs(leaf, ei);
5793         if (refs < refs_to_drop) {
5794                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
5795                           "for bytenr %Lu\n", refs_to_drop, refs, bytenr);
5796                 ret = -EINVAL;
5797                 btrfs_abort_transaction(trans, extent_root, ret);
5798                 goto out;
5799         }
5800         refs -= refs_to_drop;
5801
5802         if (refs > 0) {
5803                 if (extent_op)
5804                         __run_delayed_extent_op(extent_op, leaf, ei);
5805                 /*
5806                  * In the case of inline back ref, reference count will
5807                  * be updated by remove_extent_backref
5808                  */
5809                 if (iref) {
5810                         BUG_ON(!found_extent);
5811                 } else {
5812                         btrfs_set_extent_refs(leaf, ei, refs);
5813                         btrfs_mark_buffer_dirty(leaf);
5814                 }
5815                 if (found_extent) {
5816                         ret = remove_extent_backref(trans, extent_root, path,
5817                                                     iref, refs_to_drop,
5818                                                     is_data);
5819                         if (ret) {
5820                                 btrfs_abort_transaction(trans, extent_root, ret);
5821                                 goto out;
5822                         }
5823                 }
5824                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
5825                                  root_objectid);
5826         } else {
5827                 if (found_extent) {
5828                         BUG_ON(is_data && refs_to_drop !=
5829                                extent_data_ref_count(root, path, iref));
5830                         if (iref) {
5831                                 BUG_ON(path->slots[0] != extent_slot);
5832                         } else {
5833                                 BUG_ON(path->slots[0] != extent_slot + 1);
5834                                 path->slots[0] = extent_slot;
5835                                 num_to_del = 2;
5836                         }
5837                 }
5838
5839                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5840                                       num_to_del);
5841                 if (ret) {
5842                         btrfs_abort_transaction(trans, extent_root, ret);
5843                         goto out;
5844                 }
5845                 btrfs_release_path(path);
5846
5847                 if (is_data) {
5848                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5849                         if (ret) {
5850                                 btrfs_abort_transaction(trans, extent_root, ret);
5851                                 goto out;
5852                         }
5853                 }
5854
5855                 ret = update_block_group(root, bytenr, num_bytes, 0);
5856                 if (ret) {
5857                         btrfs_abort_transaction(trans, extent_root, ret);
5858                         goto out;
5859                 }
5860         }
5861 out:
5862         btrfs_free_path(path);
5863         return ret;
5864 }
5865
5866 /*
5867  * when we free an block, it is possible (and likely) that we free the last
5868  * delayed ref for that extent as well.  This searches the delayed ref tree for
5869  * a given extent, and if there are no other delayed refs to be processed, it
5870  * removes it from the tree.
5871  */
5872 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5873                                       struct btrfs_root *root, u64 bytenr)
5874 {
5875         struct btrfs_delayed_ref_head *head;
5876         struct btrfs_delayed_ref_root *delayed_refs;
5877         struct btrfs_delayed_ref_node *ref;
5878         struct rb_node *node;
5879         int ret = 0;
5880
5881         delayed_refs = &trans->transaction->delayed_refs;
5882         spin_lock(&delayed_refs->lock);
5883         head = btrfs_find_delayed_ref_head(trans, bytenr);
5884         if (!head)
5885                 goto out;
5886
5887         node = rb_prev(&head->node.rb_node);
5888         if (!node)
5889                 goto out;
5890
5891         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5892
5893         /* there are still entries for this ref, we can't drop it */
5894         if (ref->bytenr == bytenr)
5895                 goto out;
5896
5897         if (head->extent_op) {
5898                 if (!head->must_insert_reserved)
5899                         goto out;
5900                 btrfs_free_delayed_extent_op(head->extent_op);
5901                 head->extent_op = NULL;
5902         }
5903
5904         /*
5905          * waiting for the lock here would deadlock.  If someone else has it
5906          * locked they are already in the process of dropping it anyway
5907          */
5908         if (!mutex_trylock(&head->mutex))
5909                 goto out;
5910
5911         /*
5912          * at this point we have a head with no other entries.  Go
5913          * ahead and process it.
5914          */
5915         head->node.in_tree = 0;
5916         rb_erase(&head->node.rb_node, &delayed_refs->root);
5917
5918         delayed_refs->num_entries--;
5919
5920         /*
5921          * we don't take a ref on the node because we're removing it from the
5922          * tree, so we just steal the ref the tree was holding.
5923          */
5924         delayed_refs->num_heads--;
5925         if (list_empty(&head->cluster))
5926                 delayed_refs->num_heads_ready--;
5927
5928         list_del_init(&head->cluster);
5929         spin_unlock(&delayed_refs->lock);
5930
5931         BUG_ON(head->extent_op);
5932         if (head->must_insert_reserved)
5933                 ret = 1;
5934
5935         mutex_unlock(&head->mutex);
5936         btrfs_put_delayed_ref(&head->node);
5937         return ret;
5938 out:
5939         spin_unlock(&delayed_refs->lock);
5940         return 0;
5941 }
5942
5943 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5944                            struct btrfs_root *root,
5945                            struct extent_buffer *buf,
5946                            u64 parent, int last_ref)
5947 {
5948         struct btrfs_block_group_cache *cache = NULL;
5949         int pin = 1;
5950         int ret;
5951
5952         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5953                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5954                                         buf->start, buf->len,
5955                                         parent, root->root_key.objectid,
5956                                         btrfs_header_level(buf),
5957                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5958                 BUG_ON(ret); /* -ENOMEM */
5959         }
5960
5961         if (!last_ref)
5962                 return;
5963
5964         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5965
5966         if (btrfs_header_generation(buf) == trans->transid) {
5967                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5968                         ret = check_ref_cleanup(trans, root, buf->start);
5969                         if (!ret)
5970                                 goto out;
5971                 }
5972
5973                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5974                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5975                         goto out;
5976                 }
5977
5978                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5979
5980                 btrfs_add_free_space(cache, buf->start, buf->len);
5981                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5982                 pin = 0;
5983         }
5984 out:
5985         if (pin)
5986                 add_pinned_bytes(root->fs_info, buf->len,
5987                                  btrfs_header_level(buf),
5988                                  root->root_key.objectid);
5989
5990         /*
5991          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5992          * anymore.
5993          */
5994         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5995         btrfs_put_block_group(cache);
5996 }
5997
5998 /* Can return -ENOMEM */
5999 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6000                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6001                       u64 owner, u64 offset, int for_cow)
6002 {
6003         int ret;
6004         struct btrfs_fs_info *fs_info = root->fs_info;
6005
6006         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6007
6008         /*
6009          * tree log blocks never actually go into the extent allocation
6010          * tree, just update pinning info and exit early.
6011          */
6012         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6013                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6014                 /* unlocks the pinned mutex */
6015                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6016                 ret = 0;
6017         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6018                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6019                                         num_bytes,
6020                                         parent, root_objectid, (int)owner,
6021                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
6022         } else {
6023                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6024                                                 num_bytes,
6025                                                 parent, root_objectid, owner,
6026                                                 offset, BTRFS_DROP_DELAYED_REF,
6027                                                 NULL, for_cow);
6028         }
6029         return ret;
6030 }
6031
6032 static u64 stripe_align(struct btrfs_root *root,
6033                         struct btrfs_block_group_cache *cache,
6034                         u64 val, u64 num_bytes)
6035 {
6036         u64 ret = ALIGN(val, root->stripesize);
6037         return ret;
6038 }
6039
6040 /*
6041  * when we wait for progress in the block group caching, its because
6042  * our allocation attempt failed at least once.  So, we must sleep
6043  * and let some progress happen before we try again.
6044  *
6045  * This function will sleep at least once waiting for new free space to
6046  * show up, and then it will check the block group free space numbers
6047  * for our min num_bytes.  Another option is to have it go ahead
6048  * and look in the rbtree for a free extent of a given size, but this
6049  * is a good start.
6050  *
6051  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6052  * any of the information in this block group.
6053  */
6054 static noinline void
6055 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6056                                 u64 num_bytes)
6057 {
6058         struct btrfs_caching_control *caching_ctl;
6059
6060         caching_ctl = get_caching_control(cache);
6061         if (!caching_ctl)
6062                 return;
6063
6064         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6065                    (cache->free_space_ctl->free_space >= num_bytes));
6066
6067         put_caching_control(caching_ctl);
6068 }
6069
6070 static noinline int
6071 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6072 {
6073         struct btrfs_caching_control *caching_ctl;
6074         int ret = 0;
6075
6076         caching_ctl = get_caching_control(cache);
6077         if (!caching_ctl)
6078                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6079
6080         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6081         if (cache->cached == BTRFS_CACHE_ERROR)
6082                 ret = -EIO;
6083         put_caching_control(caching_ctl);
6084         return ret;
6085 }
6086
6087 int __get_raid_index(u64 flags)
6088 {
6089         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6090                 return BTRFS_RAID_RAID10;
6091         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6092                 return BTRFS_RAID_RAID1;
6093         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6094                 return BTRFS_RAID_DUP;
6095         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6096                 return BTRFS_RAID_RAID0;
6097         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6098                 return BTRFS_RAID_RAID5;
6099         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6100                 return BTRFS_RAID_RAID6;
6101
6102         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6103 }
6104
6105 static int get_block_group_index(struct btrfs_block_group_cache *cache)
6106 {
6107         return __get_raid_index(cache->flags);
6108 }
6109
6110 enum btrfs_loop_type {
6111         LOOP_CACHING_NOWAIT = 0,
6112         LOOP_CACHING_WAIT = 1,
6113         LOOP_ALLOC_CHUNK = 2,
6114         LOOP_NO_EMPTY_SIZE = 3,
6115 };
6116
6117 /*
6118  * walks the btree of allocated extents and find a hole of a given size.
6119  * The key ins is changed to record the hole:
6120  * ins->objectid == start position
6121  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6122  * ins->offset == the size of the hole.
6123  * Any available blocks before search_start are skipped.
6124  *
6125  * If there is no suitable free space, we will record the max size of
6126  * the free space extent currently.
6127  */
6128 static noinline int find_free_extent(struct btrfs_root *orig_root,
6129                                      u64 num_bytes, u64 empty_size,
6130                                      u64 hint_byte, struct btrfs_key *ins,
6131                                      u64 flags)
6132 {
6133         int ret = 0;
6134         struct btrfs_root *root = orig_root->fs_info->extent_root;
6135         struct btrfs_free_cluster *last_ptr = NULL;
6136         struct btrfs_block_group_cache *block_group = NULL;
6137         struct btrfs_block_group_cache *used_block_group;
6138         u64 search_start = 0;
6139         u64 max_extent_size = 0;
6140         int empty_cluster = 2 * 1024 * 1024;
6141         struct btrfs_space_info *space_info;
6142         int loop = 0;
6143         int index = __get_raid_index(flags);
6144         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6145                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6146         bool found_uncached_bg = false;
6147         bool failed_cluster_refill = false;
6148         bool failed_alloc = false;
6149         bool use_cluster = true;
6150         bool have_caching_bg = false;
6151
6152         WARN_ON(num_bytes < root->sectorsize);
6153         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
6154         ins->objectid = 0;
6155         ins->offset = 0;
6156
6157         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6158
6159         space_info = __find_space_info(root->fs_info, flags);
6160         if (!space_info) {
6161                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6162                 return -ENOSPC;
6163         }
6164
6165         /*
6166          * If the space info is for both data and metadata it means we have a
6167          * small filesystem and we can't use the clustering stuff.
6168          */
6169         if (btrfs_mixed_space_info(space_info))
6170                 use_cluster = false;
6171
6172         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6173                 last_ptr = &root->fs_info->meta_alloc_cluster;
6174                 if (!btrfs_test_opt(root, SSD))
6175                         empty_cluster = 64 * 1024;
6176         }
6177
6178         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6179             btrfs_test_opt(root, SSD)) {
6180                 last_ptr = &root->fs_info->data_alloc_cluster;
6181         }
6182
6183         if (last_ptr) {
6184                 spin_lock(&last_ptr->lock);
6185                 if (last_ptr->block_group)
6186                         hint_byte = last_ptr->window_start;
6187                 spin_unlock(&last_ptr->lock);
6188         }
6189
6190         search_start = max(search_start, first_logical_byte(root, 0));
6191         search_start = max(search_start, hint_byte);
6192
6193         if (!last_ptr)
6194                 empty_cluster = 0;
6195
6196         if (search_start == hint_byte) {
6197                 block_group = btrfs_lookup_block_group(root->fs_info,
6198                                                        search_start);
6199                 used_block_group = block_group;
6200                 /*
6201                  * we don't want to use the block group if it doesn't match our
6202                  * allocation bits, or if its not cached.
6203                  *
6204                  * However if we are re-searching with an ideal block group
6205                  * picked out then we don't care that the block group is cached.
6206                  */
6207                 if (block_group && block_group_bits(block_group, flags) &&
6208                     block_group->cached != BTRFS_CACHE_NO) {
6209                         down_read(&space_info->groups_sem);
6210                         if (list_empty(&block_group->list) ||
6211                             block_group->ro) {
6212                                 /*
6213                                  * someone is removing this block group,
6214                                  * we can't jump into the have_block_group
6215                                  * target because our list pointers are not
6216                                  * valid
6217                                  */
6218                                 btrfs_put_block_group(block_group);
6219                                 up_read(&space_info->groups_sem);
6220                         } else {
6221                                 index = get_block_group_index(block_group);
6222                                 goto have_block_group;
6223                         }
6224                 } else if (block_group) {
6225                         btrfs_put_block_group(block_group);
6226                 }
6227         }
6228 search:
6229         have_caching_bg = false;
6230         down_read(&space_info->groups_sem);
6231         list_for_each_entry(block_group, &space_info->block_groups[index],
6232                             list) {
6233                 u64 offset;
6234                 int cached;
6235
6236                 used_block_group = block_group;
6237                 btrfs_get_block_group(block_group);
6238                 search_start = block_group->key.objectid;
6239
6240                 /*
6241                  * this can happen if we end up cycling through all the
6242                  * raid types, but we want to make sure we only allocate
6243                  * for the proper type.
6244                  */
6245                 if (!block_group_bits(block_group, flags)) {
6246                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6247                                 BTRFS_BLOCK_GROUP_RAID1 |
6248                                 BTRFS_BLOCK_GROUP_RAID5 |
6249                                 BTRFS_BLOCK_GROUP_RAID6 |
6250                                 BTRFS_BLOCK_GROUP_RAID10;
6251
6252                         /*
6253                          * if they asked for extra copies and this block group
6254                          * doesn't provide them, bail.  This does allow us to
6255                          * fill raid0 from raid1.
6256                          */
6257                         if ((flags & extra) && !(block_group->flags & extra))
6258                                 goto loop;
6259                 }
6260
6261 have_block_group:
6262                 cached = block_group_cache_done(block_group);
6263                 if (unlikely(!cached)) {
6264                         found_uncached_bg = true;
6265                         ret = cache_block_group(block_group, 0);
6266                         BUG_ON(ret < 0);
6267                         ret = 0;
6268                 }
6269
6270                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6271                         goto loop;
6272                 if (unlikely(block_group->ro))
6273                         goto loop;
6274
6275                 /*
6276                  * Ok we want to try and use the cluster allocator, so
6277                  * lets look there
6278                  */
6279                 if (last_ptr) {
6280                         unsigned long aligned_cluster;
6281                         /*
6282                          * the refill lock keeps out other
6283                          * people trying to start a new cluster
6284                          */
6285                         spin_lock(&last_ptr->refill_lock);
6286                         used_block_group = last_ptr->block_group;
6287                         if (used_block_group != block_group &&
6288                             (!used_block_group ||
6289                              used_block_group->ro ||
6290                              !block_group_bits(used_block_group, flags))) {
6291                                 used_block_group = block_group;
6292                                 goto refill_cluster;
6293                         }
6294
6295                         if (used_block_group != block_group)
6296                                 btrfs_get_block_group(used_block_group);
6297
6298                         offset = btrfs_alloc_from_cluster(used_block_group,
6299                                                 last_ptr,
6300                                                 num_bytes,
6301                                                 used_block_group->key.objectid,
6302                                                 &max_extent_size);
6303                         if (offset) {
6304                                 /* we have a block, we're done */
6305                                 spin_unlock(&last_ptr->refill_lock);
6306                                 trace_btrfs_reserve_extent_cluster(root,
6307                                         block_group, search_start, num_bytes);
6308                                 goto checks;
6309                         }
6310
6311                         WARN_ON(last_ptr->block_group != used_block_group);
6312                         if (used_block_group != block_group) {
6313                                 btrfs_put_block_group(used_block_group);
6314                                 used_block_group = block_group;
6315                         }
6316 refill_cluster:
6317                         BUG_ON(used_block_group != block_group);
6318                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6319                          * set up a new clusters, so lets just skip it
6320                          * and let the allocator find whatever block
6321                          * it can find.  If we reach this point, we
6322                          * will have tried the cluster allocator
6323                          * plenty of times and not have found
6324                          * anything, so we are likely way too
6325                          * fragmented for the clustering stuff to find
6326                          * anything.
6327                          *
6328                          * However, if the cluster is taken from the
6329                          * current block group, release the cluster
6330                          * first, so that we stand a better chance of
6331                          * succeeding in the unclustered
6332                          * allocation.  */
6333                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6334                             last_ptr->block_group != block_group) {
6335                                 spin_unlock(&last_ptr->refill_lock);
6336                                 goto unclustered_alloc;
6337                         }
6338
6339                         /*
6340                          * this cluster didn't work out, free it and
6341                          * start over
6342                          */
6343                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6344
6345                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6346                                 spin_unlock(&last_ptr->refill_lock);
6347                                 goto unclustered_alloc;
6348                         }
6349
6350                         aligned_cluster = max_t(unsigned long,
6351                                                 empty_cluster + empty_size,
6352                                               block_group->full_stripe_len);
6353
6354                         /* allocate a cluster in this block group */
6355                         ret = btrfs_find_space_cluster(root, block_group,
6356                                                        last_ptr, search_start,
6357                                                        num_bytes,
6358                                                        aligned_cluster);
6359                         if (ret == 0) {
6360                                 /*
6361                                  * now pull our allocation out of this
6362                                  * cluster
6363                                  */
6364                                 offset = btrfs_alloc_from_cluster(block_group,
6365                                                         last_ptr,
6366                                                         num_bytes,
6367                                                         search_start,
6368                                                         &max_extent_size);
6369                                 if (offset) {
6370                                         /* we found one, proceed */
6371                                         spin_unlock(&last_ptr->refill_lock);
6372                                         trace_btrfs_reserve_extent_cluster(root,
6373                                                 block_group, search_start,
6374                                                 num_bytes);
6375                                         goto checks;
6376                                 }
6377                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6378                                    && !failed_cluster_refill) {
6379                                 spin_unlock(&last_ptr->refill_lock);
6380
6381                                 failed_cluster_refill = true;
6382                                 wait_block_group_cache_progress(block_group,
6383                                        num_bytes + empty_cluster + empty_size);
6384                                 goto have_block_group;
6385                         }
6386
6387                         /*
6388                          * at this point we either didn't find a cluster
6389                          * or we weren't able to allocate a block from our
6390                          * cluster.  Free the cluster we've been trying
6391                          * to use, and go to the next block group
6392                          */
6393                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6394                         spin_unlock(&last_ptr->refill_lock);
6395                         goto loop;
6396                 }
6397
6398 unclustered_alloc:
6399                 spin_lock(&block_group->free_space_ctl->tree_lock);
6400                 if (cached &&
6401                     block_group->free_space_ctl->free_space <
6402                     num_bytes + empty_cluster + empty_size) {
6403                         if (block_group->free_space_ctl->free_space >
6404                             max_extent_size)
6405                                 max_extent_size =
6406                                         block_group->free_space_ctl->free_space;
6407                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6408                         goto loop;
6409                 }
6410                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6411
6412                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6413                                                     num_bytes, empty_size,
6414                                                     &max_extent_size);
6415                 /*
6416                  * If we didn't find a chunk, and we haven't failed on this
6417                  * block group before, and this block group is in the middle of
6418                  * caching and we are ok with waiting, then go ahead and wait
6419                  * for progress to be made, and set failed_alloc to true.
6420                  *
6421                  * If failed_alloc is true then we've already waited on this
6422                  * block group once and should move on to the next block group.
6423                  */
6424                 if (!offset && !failed_alloc && !cached &&
6425                     loop > LOOP_CACHING_NOWAIT) {
6426                         wait_block_group_cache_progress(block_group,
6427                                                 num_bytes + empty_size);
6428                         failed_alloc = true;
6429                         goto have_block_group;
6430                 } else if (!offset) {
6431                         if (!cached)
6432                                 have_caching_bg = true;
6433                         goto loop;
6434                 }
6435 checks:
6436                 search_start = stripe_align(root, used_block_group,
6437                                             offset, num_bytes);
6438
6439                 /* move on to the next group */
6440                 if (search_start + num_bytes >
6441                     used_block_group->key.objectid + used_block_group->key.offset) {
6442                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6443                         goto loop;
6444                 }
6445
6446                 if (offset < search_start)
6447                         btrfs_add_free_space(used_block_group, offset,
6448                                              search_start - offset);
6449                 BUG_ON(offset > search_start);
6450
6451                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
6452                                                   alloc_type);
6453                 if (ret == -EAGAIN) {
6454                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6455                         goto loop;
6456                 }
6457
6458                 /* we are all good, lets return */
6459                 ins->objectid = search_start;
6460                 ins->offset = num_bytes;
6461
6462                 trace_btrfs_reserve_extent(orig_root, block_group,
6463                                            search_start, num_bytes);
6464                 if (used_block_group != block_group)
6465                         btrfs_put_block_group(used_block_group);
6466                 btrfs_put_block_group(block_group);
6467                 break;
6468 loop:
6469                 failed_cluster_refill = false;
6470                 failed_alloc = false;
6471                 BUG_ON(index != get_block_group_index(block_group));
6472                 if (used_block_group != block_group)
6473                         btrfs_put_block_group(used_block_group);
6474                 btrfs_put_block_group(block_group);
6475         }
6476         up_read(&space_info->groups_sem);
6477
6478         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6479                 goto search;
6480
6481         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6482                 goto search;
6483
6484         /*
6485          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6486          *                      caching kthreads as we move along
6487          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6488          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6489          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6490          *                      again
6491          */
6492         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6493                 index = 0;
6494                 loop++;
6495                 if (loop == LOOP_ALLOC_CHUNK) {
6496                         struct btrfs_trans_handle *trans;
6497
6498                         trans = btrfs_join_transaction(root);
6499                         if (IS_ERR(trans)) {
6500                                 ret = PTR_ERR(trans);
6501                                 goto out;
6502                         }
6503
6504                         ret = do_chunk_alloc(trans, root, flags,
6505                                              CHUNK_ALLOC_FORCE);
6506                         /*
6507                          * Do not bail out on ENOSPC since we
6508                          * can do more things.
6509                          */
6510                         if (ret < 0 && ret != -ENOSPC)
6511                                 btrfs_abort_transaction(trans,
6512                                                         root, ret);
6513                         else
6514                                 ret = 0;
6515                         btrfs_end_transaction(trans, root);
6516                         if (ret)
6517                                 goto out;
6518                 }
6519
6520                 if (loop == LOOP_NO_EMPTY_SIZE) {
6521                         empty_size = 0;
6522                         empty_cluster = 0;
6523                 }
6524
6525                 goto search;
6526         } else if (!ins->objectid) {
6527                 ret = -ENOSPC;
6528         } else if (ins->objectid) {
6529                 ret = 0;
6530         }
6531 out:
6532         if (ret == -ENOSPC)
6533                 ins->offset = max_extent_size;
6534         return ret;
6535 }
6536
6537 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6538                             int dump_block_groups)
6539 {
6540         struct btrfs_block_group_cache *cache;
6541         int index = 0;
6542
6543         spin_lock(&info->lock);
6544         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
6545                info->flags,
6546                info->total_bytes - info->bytes_used - info->bytes_pinned -
6547                info->bytes_reserved - info->bytes_readonly,
6548                (info->full) ? "" : "not ");
6549         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
6550                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6551                info->total_bytes, info->bytes_used, info->bytes_pinned,
6552                info->bytes_reserved, info->bytes_may_use,
6553                info->bytes_readonly);
6554         spin_unlock(&info->lock);
6555
6556         if (!dump_block_groups)
6557                 return;
6558
6559         down_read(&info->groups_sem);
6560 again:
6561         list_for_each_entry(cache, &info->block_groups[index], list) {
6562                 spin_lock(&cache->lock);
6563                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
6564                        cache->key.objectid, cache->key.offset,
6565                        btrfs_block_group_used(&cache->item), cache->pinned,
6566                        cache->reserved, cache->ro ? "[readonly]" : "");
6567                 btrfs_dump_free_space(cache, bytes);
6568                 spin_unlock(&cache->lock);
6569         }
6570         if (++index < BTRFS_NR_RAID_TYPES)
6571                 goto again;
6572         up_read(&info->groups_sem);
6573 }
6574
6575 int btrfs_reserve_extent(struct btrfs_root *root,
6576                          u64 num_bytes, u64 min_alloc_size,
6577                          u64 empty_size, u64 hint_byte,
6578                          struct btrfs_key *ins, int is_data)
6579 {
6580         bool final_tried = false;
6581         u64 flags;
6582         int ret;
6583
6584         flags = btrfs_get_alloc_profile(root, is_data);
6585 again:
6586         WARN_ON(num_bytes < root->sectorsize);
6587         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
6588                                flags);
6589
6590         if (ret == -ENOSPC) {
6591                 if (!final_tried && ins->offset) {
6592                         num_bytes = min(num_bytes >> 1, ins->offset);
6593                         num_bytes = round_down(num_bytes, root->sectorsize);
6594                         num_bytes = max(num_bytes, min_alloc_size);
6595                         if (num_bytes == min_alloc_size)
6596                                 final_tried = true;
6597                         goto again;
6598                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6599                         struct btrfs_space_info *sinfo;
6600
6601                         sinfo = __find_space_info(root->fs_info, flags);
6602                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6603                                 flags, num_bytes);
6604                         if (sinfo)
6605                                 dump_space_info(sinfo, num_bytes, 1);
6606                 }
6607         }
6608
6609         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
6610
6611         return ret;
6612 }
6613
6614 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6615                                         u64 start, u64 len, int pin)
6616 {
6617         struct btrfs_block_group_cache *cache;
6618         int ret = 0;
6619
6620         cache = btrfs_lookup_block_group(root->fs_info, start);
6621         if (!cache) {
6622                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6623                         start);
6624                 return -ENOSPC;
6625         }
6626
6627         if (btrfs_test_opt(root, DISCARD))
6628                 ret = btrfs_discard_extent(root, start, len, NULL);
6629
6630         if (pin)
6631                 pin_down_extent(root, cache, start, len, 1);
6632         else {
6633                 btrfs_add_free_space(cache, start, len);
6634                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6635         }
6636         btrfs_put_block_group(cache);
6637
6638         trace_btrfs_reserved_extent_free(root, start, len);
6639
6640         return ret;
6641 }
6642
6643 int btrfs_free_reserved_extent(struct btrfs_root *root,
6644                                         u64 start, u64 len)
6645 {
6646         return __btrfs_free_reserved_extent(root, start, len, 0);
6647 }
6648
6649 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6650                                        u64 start, u64 len)
6651 {
6652         return __btrfs_free_reserved_extent(root, start, len, 1);
6653 }
6654
6655 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6656                                       struct btrfs_root *root,
6657                                       u64 parent, u64 root_objectid,
6658                                       u64 flags, u64 owner, u64 offset,
6659                                       struct btrfs_key *ins, int ref_mod)
6660 {
6661         int ret;
6662         struct btrfs_fs_info *fs_info = root->fs_info;
6663         struct btrfs_extent_item *extent_item;
6664         struct btrfs_extent_inline_ref *iref;
6665         struct btrfs_path *path;
6666         struct extent_buffer *leaf;
6667         int type;
6668         u32 size;
6669
6670         if (parent > 0)
6671                 type = BTRFS_SHARED_DATA_REF_KEY;
6672         else
6673                 type = BTRFS_EXTENT_DATA_REF_KEY;
6674
6675         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6676
6677         path = btrfs_alloc_path();
6678         if (!path)
6679                 return -ENOMEM;
6680
6681         path->leave_spinning = 1;
6682         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6683                                       ins, size);
6684         if (ret) {
6685                 btrfs_free_path(path);
6686                 return ret;
6687         }
6688
6689         leaf = path->nodes[0];
6690         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6691                                      struct btrfs_extent_item);
6692         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6693         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6694         btrfs_set_extent_flags(leaf, extent_item,
6695                                flags | BTRFS_EXTENT_FLAG_DATA);
6696
6697         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6698         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6699         if (parent > 0) {
6700                 struct btrfs_shared_data_ref *ref;
6701                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6702                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6703                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6704         } else {
6705                 struct btrfs_extent_data_ref *ref;
6706                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6707                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6708                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6709                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6710                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6711         }
6712
6713         btrfs_mark_buffer_dirty(path->nodes[0]);
6714         btrfs_free_path(path);
6715
6716         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6717         if (ret) { /* -ENOENT, logic error */
6718                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6719                         ins->objectid, ins->offset);
6720                 BUG();
6721         }
6722         return ret;
6723 }
6724
6725 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6726                                      struct btrfs_root *root,
6727                                      u64 parent, u64 root_objectid,
6728                                      u64 flags, struct btrfs_disk_key *key,
6729                                      int level, struct btrfs_key *ins)
6730 {
6731         int ret;
6732         struct btrfs_fs_info *fs_info = root->fs_info;
6733         struct btrfs_extent_item *extent_item;
6734         struct btrfs_tree_block_info *block_info;
6735         struct btrfs_extent_inline_ref *iref;
6736         struct btrfs_path *path;
6737         struct extent_buffer *leaf;
6738         u32 size = sizeof(*extent_item) + sizeof(*iref);
6739         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6740                                                  SKINNY_METADATA);
6741
6742         if (!skinny_metadata)
6743                 size += sizeof(*block_info);
6744
6745         path = btrfs_alloc_path();
6746         if (!path)
6747                 return -ENOMEM;
6748
6749         path->leave_spinning = 1;
6750         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6751                                       ins, size);
6752         if (ret) {
6753                 btrfs_free_path(path);
6754                 return ret;
6755         }
6756
6757         leaf = path->nodes[0];
6758         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6759                                      struct btrfs_extent_item);
6760         btrfs_set_extent_refs(leaf, extent_item, 1);
6761         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6762         btrfs_set_extent_flags(leaf, extent_item,
6763                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6764
6765         if (skinny_metadata) {
6766                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6767         } else {
6768                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6769                 btrfs_set_tree_block_key(leaf, block_info, key);
6770                 btrfs_set_tree_block_level(leaf, block_info, level);
6771                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6772         }
6773
6774         if (parent > 0) {
6775                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6776                 btrfs_set_extent_inline_ref_type(leaf, iref,
6777                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6778                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6779         } else {
6780                 btrfs_set_extent_inline_ref_type(leaf, iref,
6781                                                  BTRFS_TREE_BLOCK_REF_KEY);
6782                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6783         }
6784
6785         btrfs_mark_buffer_dirty(leaf);
6786         btrfs_free_path(path);
6787
6788         ret = update_block_group(root, ins->objectid, root->leafsize, 1);
6789         if (ret) { /* -ENOENT, logic error */
6790                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6791                         ins->objectid, ins->offset);
6792                 BUG();
6793         }
6794         return ret;
6795 }
6796
6797 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6798                                      struct btrfs_root *root,
6799                                      u64 root_objectid, u64 owner,
6800                                      u64 offset, struct btrfs_key *ins)
6801 {
6802         int ret;
6803
6804         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6805
6806         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6807                                          ins->offset, 0,
6808                                          root_objectid, owner, offset,
6809                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6810         return ret;
6811 }
6812
6813 /*
6814  * this is used by the tree logging recovery code.  It records that
6815  * an extent has been allocated and makes sure to clear the free
6816  * space cache bits as well
6817  */
6818 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6819                                    struct btrfs_root *root,
6820                                    u64 root_objectid, u64 owner, u64 offset,
6821                                    struct btrfs_key *ins)
6822 {
6823         int ret;
6824         struct btrfs_block_group_cache *block_group;
6825
6826         /*
6827          * Mixed block groups will exclude before processing the log so we only
6828          * need to do the exlude dance if this fs isn't mixed.
6829          */
6830         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
6831                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
6832                 if (ret)
6833                         return ret;
6834         }
6835
6836         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6837         if (!block_group)
6838                 return -EINVAL;
6839
6840         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6841                                           RESERVE_ALLOC_NO_ACCOUNT);
6842         BUG_ON(ret); /* logic error */
6843         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6844                                          0, owner, offset, ins, 1);
6845         btrfs_put_block_group(block_group);
6846         return ret;
6847 }
6848
6849 static struct extent_buffer *
6850 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6851                       u64 bytenr, u32 blocksize, int level)
6852 {
6853         struct extent_buffer *buf;
6854
6855         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6856         if (!buf)
6857                 return ERR_PTR(-ENOMEM);
6858         btrfs_set_header_generation(buf, trans->transid);
6859         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6860         btrfs_tree_lock(buf);
6861         clean_tree_block(trans, root, buf);
6862         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6863
6864         btrfs_set_lock_blocking(buf);
6865         btrfs_set_buffer_uptodate(buf);
6866
6867         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6868                 /*
6869                  * we allow two log transactions at a time, use different
6870                  * EXENT bit to differentiate dirty pages.
6871                  */
6872                 if (root->log_transid % 2 == 0)
6873                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6874                                         buf->start + buf->len - 1, GFP_NOFS);
6875                 else
6876                         set_extent_new(&root->dirty_log_pages, buf->start,
6877                                         buf->start + buf->len - 1, GFP_NOFS);
6878         } else {
6879                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6880                          buf->start + buf->len - 1, GFP_NOFS);
6881         }
6882         trans->blocks_used++;
6883         /* this returns a buffer locked for blocking */
6884         return buf;
6885 }
6886
6887 static struct btrfs_block_rsv *
6888 use_block_rsv(struct btrfs_trans_handle *trans,
6889               struct btrfs_root *root, u32 blocksize)
6890 {
6891         struct btrfs_block_rsv *block_rsv;
6892         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6893         int ret;
6894         bool global_updated = false;
6895
6896         block_rsv = get_block_rsv(trans, root);
6897
6898         if (unlikely(block_rsv->size == 0))
6899                 goto try_reserve;
6900 again:
6901         ret = block_rsv_use_bytes(block_rsv, blocksize);
6902         if (!ret)
6903                 return block_rsv;
6904
6905         if (block_rsv->failfast)
6906                 return ERR_PTR(ret);
6907
6908         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
6909                 global_updated = true;
6910                 update_global_block_rsv(root->fs_info);
6911                 goto again;
6912         }
6913
6914         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6915                 static DEFINE_RATELIMIT_STATE(_rs,
6916                                 DEFAULT_RATELIMIT_INTERVAL * 10,
6917                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
6918                 if (__ratelimit(&_rs))
6919                         WARN(1, KERN_DEBUG
6920                                 "btrfs: block rsv returned %d\n", ret);
6921         }
6922 try_reserve:
6923         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
6924                                      BTRFS_RESERVE_NO_FLUSH);
6925         if (!ret)
6926                 return block_rsv;
6927         /*
6928          * If we couldn't reserve metadata bytes try and use some from
6929          * the global reserve if its space type is the same as the global
6930          * reservation.
6931          */
6932         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
6933             block_rsv->space_info == global_rsv->space_info) {
6934                 ret = block_rsv_use_bytes(global_rsv, blocksize);
6935                 if (!ret)
6936                         return global_rsv;
6937         }
6938         return ERR_PTR(ret);
6939 }
6940
6941 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6942                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6943 {
6944         block_rsv_add_bytes(block_rsv, blocksize, 0);
6945         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6946 }
6947
6948 /*
6949  * finds a free extent and does all the dirty work required for allocation
6950  * returns the key for the extent through ins, and a tree buffer for
6951  * the first block of the extent through buf.
6952  *
6953  * returns the tree buffer or NULL.
6954  */
6955 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6956                                         struct btrfs_root *root, u32 blocksize,
6957                                         u64 parent, u64 root_objectid,
6958                                         struct btrfs_disk_key *key, int level,
6959                                         u64 hint, u64 empty_size)
6960 {
6961         struct btrfs_key ins;
6962         struct btrfs_block_rsv *block_rsv;
6963         struct extent_buffer *buf;
6964         u64 flags = 0;
6965         int ret;
6966         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6967                                                  SKINNY_METADATA);
6968
6969         block_rsv = use_block_rsv(trans, root, blocksize);
6970         if (IS_ERR(block_rsv))
6971                 return ERR_CAST(block_rsv);
6972
6973         ret = btrfs_reserve_extent(root, blocksize, blocksize,
6974                                    empty_size, hint, &ins, 0);
6975         if (ret) {
6976                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6977                 return ERR_PTR(ret);
6978         }
6979
6980         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6981                                     blocksize, level);
6982         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6983
6984         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6985                 if (parent == 0)
6986                         parent = ins.objectid;
6987                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6988         } else
6989                 BUG_ON(parent > 0);
6990
6991         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6992                 struct btrfs_delayed_extent_op *extent_op;
6993                 extent_op = btrfs_alloc_delayed_extent_op();
6994                 BUG_ON(!extent_op); /* -ENOMEM */
6995                 if (key)
6996                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6997                 else
6998                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6999                 extent_op->flags_to_set = flags;
7000                 if (skinny_metadata)
7001                         extent_op->update_key = 0;
7002                 else
7003                         extent_op->update_key = 1;
7004                 extent_op->update_flags = 1;
7005                 extent_op->is_data = 0;
7006                 extent_op->level = level;
7007
7008                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7009                                         ins.objectid,
7010                                         ins.offset, parent, root_objectid,
7011                                         level, BTRFS_ADD_DELAYED_EXTENT,
7012                                         extent_op, 0);
7013                 BUG_ON(ret); /* -ENOMEM */
7014         }
7015         return buf;
7016 }
7017
7018 struct walk_control {
7019         u64 refs[BTRFS_MAX_LEVEL];
7020         u64 flags[BTRFS_MAX_LEVEL];
7021         struct btrfs_key update_progress;
7022         int stage;
7023         int level;
7024         int shared_level;
7025         int update_ref;
7026         int keep_locks;
7027         int reada_slot;
7028         int reada_count;
7029         int for_reloc;
7030 };
7031
7032 #define DROP_REFERENCE  1
7033 #define UPDATE_BACKREF  2
7034
7035 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7036                                      struct btrfs_root *root,
7037                                      struct walk_control *wc,
7038                                      struct btrfs_path *path)
7039 {
7040         u64 bytenr;
7041         u64 generation;
7042         u64 refs;
7043         u64 flags;
7044         u32 nritems;
7045         u32 blocksize;
7046         struct btrfs_key key;
7047         struct extent_buffer *eb;
7048         int ret;
7049         int slot;
7050         int nread = 0;
7051
7052         if (path->slots[wc->level] < wc->reada_slot) {
7053                 wc->reada_count = wc->reada_count * 2 / 3;
7054                 wc->reada_count = max(wc->reada_count, 2);
7055         } else {
7056                 wc->reada_count = wc->reada_count * 3 / 2;
7057                 wc->reada_count = min_t(int, wc->reada_count,
7058                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7059         }
7060
7061         eb = path->nodes[wc->level];
7062         nritems = btrfs_header_nritems(eb);
7063         blocksize = btrfs_level_size(root, wc->level - 1);
7064
7065         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7066                 if (nread >= wc->reada_count)
7067                         break;
7068
7069                 cond_resched();
7070                 bytenr = btrfs_node_blockptr(eb, slot);
7071                 generation = btrfs_node_ptr_generation(eb, slot);
7072
7073                 if (slot == path->slots[wc->level])
7074                         goto reada;
7075
7076                 if (wc->stage == UPDATE_BACKREF &&
7077                     generation <= root->root_key.offset)
7078                         continue;
7079
7080                 /* We don't lock the tree block, it's OK to be racy here */
7081                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7082                                                wc->level - 1, 1, &refs,
7083                                                &flags);
7084                 /* We don't care about errors in readahead. */
7085                 if (ret < 0)
7086                         continue;
7087                 BUG_ON(refs == 0);
7088
7089                 if (wc->stage == DROP_REFERENCE) {
7090                         if (refs == 1)
7091                                 goto reada;
7092
7093                         if (wc->level == 1 &&
7094                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7095                                 continue;
7096                         if (!wc->update_ref ||
7097                             generation <= root->root_key.offset)
7098                                 continue;
7099                         btrfs_node_key_to_cpu(eb, &key, slot);
7100                         ret = btrfs_comp_cpu_keys(&key,
7101                                                   &wc->update_progress);
7102                         if (ret < 0)
7103                                 continue;
7104                 } else {
7105                         if (wc->level == 1 &&
7106                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7107                                 continue;
7108                 }
7109 reada:
7110                 ret = readahead_tree_block(root, bytenr, blocksize,
7111                                            generation);
7112                 if (ret)
7113                         break;
7114                 nread++;
7115         }
7116         wc->reada_slot = slot;
7117 }
7118
7119 /*
7120  * helper to process tree block while walking down the tree.
7121  *
7122  * when wc->stage == UPDATE_BACKREF, this function updates
7123  * back refs for pointers in the block.
7124  *
7125  * NOTE: return value 1 means we should stop walking down.
7126  */
7127 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7128                                    struct btrfs_root *root,
7129                                    struct btrfs_path *path,
7130                                    struct walk_control *wc, int lookup_info)
7131 {
7132         int level = wc->level;
7133         struct extent_buffer *eb = path->nodes[level];
7134         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7135         int ret;
7136
7137         if (wc->stage == UPDATE_BACKREF &&
7138             btrfs_header_owner(eb) != root->root_key.objectid)
7139                 return 1;
7140
7141         /*
7142          * when reference count of tree block is 1, it won't increase
7143          * again. once full backref flag is set, we never clear it.
7144          */
7145         if (lookup_info &&
7146             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7147              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7148                 BUG_ON(!path->locks[level]);
7149                 ret = btrfs_lookup_extent_info(trans, root,
7150                                                eb->start, level, 1,
7151                                                &wc->refs[level],
7152                                                &wc->flags[level]);
7153                 BUG_ON(ret == -ENOMEM);
7154                 if (ret)
7155                         return ret;
7156                 BUG_ON(wc->refs[level] == 0);
7157         }
7158
7159         if (wc->stage == DROP_REFERENCE) {
7160                 if (wc->refs[level] > 1)
7161                         return 1;
7162
7163                 if (path->locks[level] && !wc->keep_locks) {
7164                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7165                         path->locks[level] = 0;
7166                 }
7167                 return 0;
7168         }
7169
7170         /* wc->stage == UPDATE_BACKREF */
7171         if (!(wc->flags[level] & flag)) {
7172                 BUG_ON(!path->locks[level]);
7173                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
7174                 BUG_ON(ret); /* -ENOMEM */
7175                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
7176                 BUG_ON(ret); /* -ENOMEM */
7177                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7178                                                   eb->len, flag,
7179                                                   btrfs_header_level(eb), 0);
7180                 BUG_ON(ret); /* -ENOMEM */
7181                 wc->flags[level] |= flag;
7182         }
7183
7184         /*
7185          * the block is shared by multiple trees, so it's not good to
7186          * keep the tree lock
7187          */
7188         if (path->locks[level] && level > 0) {
7189                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7190                 path->locks[level] = 0;
7191         }
7192         return 0;
7193 }
7194
7195 /*
7196  * helper to process tree block pointer.
7197  *
7198  * when wc->stage == DROP_REFERENCE, this function checks
7199  * reference count of the block pointed to. if the block
7200  * is shared and we need update back refs for the subtree
7201  * rooted at the block, this function changes wc->stage to
7202  * UPDATE_BACKREF. if the block is shared and there is no
7203  * need to update back, this function drops the reference
7204  * to the block.
7205  *
7206  * NOTE: return value 1 means we should stop walking down.
7207  */
7208 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
7209                                  struct btrfs_root *root,
7210                                  struct btrfs_path *path,
7211                                  struct walk_control *wc, int *lookup_info)
7212 {
7213         u64 bytenr;
7214         u64 generation;
7215         u64 parent;
7216         u32 blocksize;
7217         struct btrfs_key key;
7218         struct extent_buffer *next;
7219         int level = wc->level;
7220         int reada = 0;
7221         int ret = 0;
7222
7223         generation = btrfs_node_ptr_generation(path->nodes[level],
7224                                                path->slots[level]);
7225         /*
7226          * if the lower level block was created before the snapshot
7227          * was created, we know there is no need to update back refs
7228          * for the subtree
7229          */
7230         if (wc->stage == UPDATE_BACKREF &&
7231             generation <= root->root_key.offset) {
7232                 *lookup_info = 1;
7233                 return 1;
7234         }
7235
7236         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7237         blocksize = btrfs_level_size(root, level - 1);
7238
7239         next = btrfs_find_tree_block(root, bytenr, blocksize);
7240         if (!next) {
7241                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
7242                 if (!next)
7243                         return -ENOMEM;
7244                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
7245                                                level - 1);
7246                 reada = 1;
7247         }
7248         btrfs_tree_lock(next);
7249         btrfs_set_lock_blocking(next);
7250
7251         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7252                                        &wc->refs[level - 1],
7253                                        &wc->flags[level - 1]);
7254         if (ret < 0) {
7255                 btrfs_tree_unlock(next);
7256                 return ret;
7257         }
7258
7259         if (unlikely(wc->refs[level - 1] == 0)) {
7260                 btrfs_err(root->fs_info, "Missing references.");
7261                 BUG();
7262         }
7263         *lookup_info = 0;
7264
7265         if (wc->stage == DROP_REFERENCE) {
7266                 if (wc->refs[level - 1] > 1) {
7267                         if (level == 1 &&
7268                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7269                                 goto skip;
7270
7271                         if (!wc->update_ref ||
7272                             generation <= root->root_key.offset)
7273                                 goto skip;
7274
7275                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7276                                               path->slots[level]);
7277                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7278                         if (ret < 0)
7279                                 goto skip;
7280
7281                         wc->stage = UPDATE_BACKREF;
7282                         wc->shared_level = level - 1;
7283                 }
7284         } else {
7285                 if (level == 1 &&
7286                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7287                         goto skip;
7288         }
7289
7290         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7291                 btrfs_tree_unlock(next);
7292                 free_extent_buffer(next);
7293                 next = NULL;
7294                 *lookup_info = 1;
7295         }
7296
7297         if (!next) {
7298                 if (reada && level == 1)
7299                         reada_walk_down(trans, root, wc, path);
7300                 next = read_tree_block(root, bytenr, blocksize, generation);
7301                 if (!next || !extent_buffer_uptodate(next)) {
7302                         free_extent_buffer(next);
7303                         return -EIO;
7304                 }
7305                 btrfs_tree_lock(next);
7306                 btrfs_set_lock_blocking(next);
7307         }
7308
7309         level--;
7310         BUG_ON(level != btrfs_header_level(next));
7311         path->nodes[level] = next;
7312         path->slots[level] = 0;
7313         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7314         wc->level = level;
7315         if (wc->level == 1)
7316                 wc->reada_slot = 0;
7317         return 0;
7318 skip:
7319         wc->refs[level - 1] = 0;
7320         wc->flags[level - 1] = 0;
7321         if (wc->stage == DROP_REFERENCE) {
7322                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7323                         parent = path->nodes[level]->start;
7324                 } else {
7325                         BUG_ON(root->root_key.objectid !=
7326                                btrfs_header_owner(path->nodes[level]));
7327                         parent = 0;
7328                 }
7329
7330                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7331                                 root->root_key.objectid, level - 1, 0, 0);
7332                 BUG_ON(ret); /* -ENOMEM */
7333         }
7334         btrfs_tree_unlock(next);
7335         free_extent_buffer(next);
7336         *lookup_info = 1;
7337         return 1;
7338 }
7339
7340 /*
7341  * helper to process tree block while walking up the tree.
7342  *
7343  * when wc->stage == DROP_REFERENCE, this function drops
7344  * reference count on the block.
7345  *
7346  * when wc->stage == UPDATE_BACKREF, this function changes
7347  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7348  * to UPDATE_BACKREF previously while processing the block.
7349  *
7350  * NOTE: return value 1 means we should stop walking up.
7351  */
7352 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7353                                  struct btrfs_root *root,
7354                                  struct btrfs_path *path,
7355                                  struct walk_control *wc)
7356 {
7357         int ret;
7358         int level = wc->level;
7359         struct extent_buffer *eb = path->nodes[level];
7360         u64 parent = 0;
7361
7362         if (wc->stage == UPDATE_BACKREF) {
7363                 BUG_ON(wc->shared_level < level);
7364                 if (level < wc->shared_level)
7365                         goto out;
7366
7367                 ret = find_next_key(path, level + 1, &wc->update_progress);
7368                 if (ret > 0)
7369                         wc->update_ref = 0;
7370
7371                 wc->stage = DROP_REFERENCE;
7372                 wc->shared_level = -1;
7373                 path->slots[level] = 0;
7374
7375                 /*
7376                  * check reference count again if the block isn't locked.
7377                  * we should start walking down the tree again if reference
7378                  * count is one.
7379                  */
7380                 if (!path->locks[level]) {
7381                         BUG_ON(level == 0);
7382                         btrfs_tree_lock(eb);
7383                         btrfs_set_lock_blocking(eb);
7384                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7385
7386                         ret = btrfs_lookup_extent_info(trans, root,
7387                                                        eb->start, level, 1,
7388                                                        &wc->refs[level],
7389                                                        &wc->flags[level]);
7390                         if (ret < 0) {
7391                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7392                                 path->locks[level] = 0;
7393                                 return ret;
7394                         }
7395                         BUG_ON(wc->refs[level] == 0);
7396                         if (wc->refs[level] == 1) {
7397                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7398                                 path->locks[level] = 0;
7399                                 return 1;
7400                         }
7401                 }
7402         }
7403
7404         /* wc->stage == DROP_REFERENCE */
7405         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7406
7407         if (wc->refs[level] == 1) {
7408                 if (level == 0) {
7409                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7410                                 ret = btrfs_dec_ref(trans, root, eb, 1,
7411                                                     wc->for_reloc);
7412                         else
7413                                 ret = btrfs_dec_ref(trans, root, eb, 0,
7414                                                     wc->for_reloc);
7415                         BUG_ON(ret); /* -ENOMEM */
7416                 }
7417                 /* make block locked assertion in clean_tree_block happy */
7418                 if (!path->locks[level] &&
7419                     btrfs_header_generation(eb) == trans->transid) {
7420                         btrfs_tree_lock(eb);
7421                         btrfs_set_lock_blocking(eb);
7422                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7423                 }
7424                 clean_tree_block(trans, root, eb);
7425         }
7426
7427         if (eb == root->node) {
7428                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7429                         parent = eb->start;
7430                 else
7431                         BUG_ON(root->root_key.objectid !=
7432                                btrfs_header_owner(eb));
7433         } else {
7434                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7435                         parent = path->nodes[level + 1]->start;
7436                 else
7437                         BUG_ON(root->root_key.objectid !=
7438                                btrfs_header_owner(path->nodes[level + 1]));
7439         }
7440
7441         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7442 out:
7443         wc->refs[level] = 0;
7444         wc->flags[level] = 0;
7445         return 0;
7446 }
7447
7448 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7449                                    struct btrfs_root *root,
7450                                    struct btrfs_path *path,
7451                                    struct walk_control *wc)
7452 {
7453         int level = wc->level;
7454         int lookup_info = 1;
7455         int ret;
7456
7457         while (level >= 0) {
7458                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
7459                 if (ret > 0)
7460                         break;
7461
7462                 if (level == 0)
7463                         break;
7464
7465                 if (path->slots[level] >=
7466                     btrfs_header_nritems(path->nodes[level]))
7467                         break;
7468
7469                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
7470                 if (ret > 0) {
7471                         path->slots[level]++;
7472                         continue;
7473                 } else if (ret < 0)
7474                         return ret;
7475                 level = wc->level;
7476         }
7477         return 0;
7478 }
7479
7480 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
7481                                  struct btrfs_root *root,
7482                                  struct btrfs_path *path,
7483                                  struct walk_control *wc, int max_level)
7484 {
7485         int level = wc->level;
7486         int ret;
7487
7488         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
7489         while (level < max_level && path->nodes[level]) {
7490                 wc->level = level;
7491                 if (path->slots[level] + 1 <
7492                     btrfs_header_nritems(path->nodes[level])) {
7493                         path->slots[level]++;
7494                         return 0;
7495                 } else {
7496                         ret = walk_up_proc(trans, root, path, wc);
7497                         if (ret > 0)
7498                                 return 0;
7499
7500                         if (path->locks[level]) {
7501                                 btrfs_tree_unlock_rw(path->nodes[level],
7502                                                      path->locks[level]);
7503                                 path->locks[level] = 0;
7504                         }
7505                         free_extent_buffer(path->nodes[level]);
7506                         path->nodes[level] = NULL;
7507                         level++;
7508                 }
7509         }
7510         return 1;
7511 }
7512
7513 /*
7514  * drop a subvolume tree.
7515  *
7516  * this function traverses the tree freeing any blocks that only
7517  * referenced by the tree.
7518  *
7519  * when a shared tree block is found. this function decreases its
7520  * reference count by one. if update_ref is true, this function
7521  * also make sure backrefs for the shared block and all lower level
7522  * blocks are properly updated.
7523  *
7524  * If called with for_reloc == 0, may exit early with -EAGAIN
7525  */
7526 int btrfs_drop_snapshot(struct btrfs_root *root,
7527                          struct btrfs_block_rsv *block_rsv, int update_ref,
7528                          int for_reloc)
7529 {
7530         struct btrfs_path *path;
7531         struct btrfs_trans_handle *trans;
7532         struct btrfs_root *tree_root = root->fs_info->tree_root;
7533         struct btrfs_root_item *root_item = &root->root_item;
7534         struct walk_control *wc;
7535         struct btrfs_key key;
7536         int err = 0;
7537         int ret;
7538         int level;
7539         bool root_dropped = false;
7540
7541         path = btrfs_alloc_path();
7542         if (!path) {
7543                 err = -ENOMEM;
7544                 goto out;
7545         }
7546
7547         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7548         if (!wc) {
7549                 btrfs_free_path(path);
7550                 err = -ENOMEM;
7551                 goto out;
7552         }
7553
7554         trans = btrfs_start_transaction(tree_root, 0);
7555         if (IS_ERR(trans)) {
7556                 err = PTR_ERR(trans);
7557                 goto out_free;
7558         }
7559
7560         if (block_rsv)
7561                 trans->block_rsv = block_rsv;
7562
7563         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
7564                 level = btrfs_header_level(root->node);
7565                 path->nodes[level] = btrfs_lock_root_node(root);
7566                 btrfs_set_lock_blocking(path->nodes[level]);
7567                 path->slots[level] = 0;
7568                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7569                 memset(&wc->update_progress, 0,
7570                        sizeof(wc->update_progress));
7571         } else {
7572                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
7573                 memcpy(&wc->update_progress, &key,
7574                        sizeof(wc->update_progress));
7575
7576                 level = root_item->drop_level;
7577                 BUG_ON(level == 0);
7578                 path->lowest_level = level;
7579                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
7580                 path->lowest_level = 0;
7581                 if (ret < 0) {
7582                         err = ret;
7583                         goto out_end_trans;
7584                 }
7585                 WARN_ON(ret > 0);
7586
7587                 /*
7588                  * unlock our path, this is safe because only this
7589                  * function is allowed to delete this snapshot
7590                  */
7591                 btrfs_unlock_up_safe(path, 0);
7592
7593                 level = btrfs_header_level(root->node);
7594                 while (1) {
7595                         btrfs_tree_lock(path->nodes[level]);
7596                         btrfs_set_lock_blocking(path->nodes[level]);
7597                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7598
7599                         ret = btrfs_lookup_extent_info(trans, root,
7600                                                 path->nodes[level]->start,
7601                                                 level, 1, &wc->refs[level],
7602                                                 &wc->flags[level]);
7603                         if (ret < 0) {
7604                                 err = ret;
7605                                 goto out_end_trans;
7606                         }
7607                         BUG_ON(wc->refs[level] == 0);
7608
7609                         if (level == root_item->drop_level)
7610                                 break;
7611
7612                         btrfs_tree_unlock(path->nodes[level]);
7613                         path->locks[level] = 0;
7614                         WARN_ON(wc->refs[level] != 1);
7615                         level--;
7616                 }
7617         }
7618
7619         wc->level = level;
7620         wc->shared_level = -1;
7621         wc->stage = DROP_REFERENCE;
7622         wc->update_ref = update_ref;
7623         wc->keep_locks = 0;
7624         wc->for_reloc = for_reloc;
7625         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7626
7627         while (1) {
7628
7629                 ret = walk_down_tree(trans, root, path, wc);
7630                 if (ret < 0) {
7631                         err = ret;
7632                         break;
7633                 }
7634
7635                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7636                 if (ret < 0) {
7637                         err = ret;
7638                         break;
7639                 }
7640
7641                 if (ret > 0) {
7642                         BUG_ON(wc->stage != DROP_REFERENCE);
7643                         break;
7644                 }
7645
7646                 if (wc->stage == DROP_REFERENCE) {
7647                         level = wc->level;
7648                         btrfs_node_key(path->nodes[level],
7649                                        &root_item->drop_progress,
7650                                        path->slots[level]);
7651                         root_item->drop_level = level;
7652                 }
7653
7654                 BUG_ON(wc->level == 0);
7655                 if (btrfs_should_end_transaction(trans, tree_root) ||
7656                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
7657                         ret = btrfs_update_root(trans, tree_root,
7658                                                 &root->root_key,
7659                                                 root_item);
7660                         if (ret) {
7661                                 btrfs_abort_transaction(trans, tree_root, ret);
7662                                 err = ret;
7663                                 goto out_end_trans;
7664                         }
7665
7666                         btrfs_end_transaction_throttle(trans, tree_root);
7667                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
7668                                 pr_debug("btrfs: drop snapshot early exit\n");
7669                                 err = -EAGAIN;
7670                                 goto out_free;
7671                         }
7672
7673                         trans = btrfs_start_transaction(tree_root, 0);
7674                         if (IS_ERR(trans)) {
7675                                 err = PTR_ERR(trans);
7676                                 goto out_free;
7677                         }
7678                         if (block_rsv)
7679                                 trans->block_rsv = block_rsv;
7680                 }
7681         }
7682         btrfs_release_path(path);
7683         if (err)
7684                 goto out_end_trans;
7685
7686         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7687         if (ret) {
7688                 btrfs_abort_transaction(trans, tree_root, ret);
7689                 goto out_end_trans;
7690         }
7691
7692         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7693                 ret = btrfs_find_root(tree_root, &root->root_key, path,
7694                                       NULL, NULL);
7695                 if (ret < 0) {
7696                         btrfs_abort_transaction(trans, tree_root, ret);
7697                         err = ret;
7698                         goto out_end_trans;
7699                 } else if (ret > 0) {
7700                         /* if we fail to delete the orphan item this time
7701                          * around, it'll get picked up the next time.
7702                          *
7703                          * The most common failure here is just -ENOENT.
7704                          */
7705                         btrfs_del_orphan_item(trans, tree_root,
7706                                               root->root_key.objectid);
7707                 }
7708         }
7709
7710         if (root->in_radix) {
7711                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
7712         } else {
7713                 free_extent_buffer(root->node);
7714                 free_extent_buffer(root->commit_root);
7715                 btrfs_put_fs_root(root);
7716         }
7717         root_dropped = true;
7718 out_end_trans:
7719         btrfs_end_transaction_throttle(trans, tree_root);
7720 out_free:
7721         kfree(wc);
7722         btrfs_free_path(path);
7723 out:
7724         /*
7725          * So if we need to stop dropping the snapshot for whatever reason we
7726          * need to make sure to add it back to the dead root list so that we
7727          * keep trying to do the work later.  This also cleans up roots if we
7728          * don't have it in the radix (like when we recover after a power fail
7729          * or unmount) so we don't leak memory.
7730          */
7731         if (!for_reloc && root_dropped == false)
7732                 btrfs_add_dead_root(root);
7733         if (err)
7734                 btrfs_std_error(root->fs_info, err);
7735         return err;
7736 }
7737
7738 /*
7739  * drop subtree rooted at tree block 'node'.
7740  *
7741  * NOTE: this function will unlock and release tree block 'node'
7742  * only used by relocation code
7743  */
7744 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7745                         struct btrfs_root *root,
7746                         struct extent_buffer *node,
7747                         struct extent_buffer *parent)
7748 {
7749         struct btrfs_path *path;
7750         struct walk_control *wc;
7751         int level;
7752         int parent_level;
7753         int ret = 0;
7754         int wret;
7755
7756         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7757
7758         path = btrfs_alloc_path();
7759         if (!path)
7760                 return -ENOMEM;
7761
7762         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7763         if (!wc) {
7764                 btrfs_free_path(path);
7765                 return -ENOMEM;
7766         }
7767
7768         btrfs_assert_tree_locked(parent);
7769         parent_level = btrfs_header_level(parent);
7770         extent_buffer_get(parent);
7771         path->nodes[parent_level] = parent;
7772         path->slots[parent_level] = btrfs_header_nritems(parent);
7773
7774         btrfs_assert_tree_locked(node);
7775         level = btrfs_header_level(node);
7776         path->nodes[level] = node;
7777         path->slots[level] = 0;
7778         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7779
7780         wc->refs[parent_level] = 1;
7781         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7782         wc->level = level;
7783         wc->shared_level = -1;
7784         wc->stage = DROP_REFERENCE;
7785         wc->update_ref = 0;
7786         wc->keep_locks = 1;
7787         wc->for_reloc = 1;
7788         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7789
7790         while (1) {
7791                 wret = walk_down_tree(trans, root, path, wc);
7792                 if (wret < 0) {
7793                         ret = wret;
7794                         break;
7795                 }
7796
7797                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7798                 if (wret < 0)
7799                         ret = wret;
7800                 if (wret != 0)
7801                         break;
7802         }
7803
7804         kfree(wc);
7805         btrfs_free_path(path);
7806         return ret;
7807 }
7808
7809 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7810 {
7811         u64 num_devices;
7812         u64 stripped;
7813
7814         /*
7815          * if restripe for this chunk_type is on pick target profile and
7816          * return, otherwise do the usual balance
7817          */
7818         stripped = get_restripe_target(root->fs_info, flags);
7819         if (stripped)
7820                 return extended_to_chunk(stripped);
7821
7822         /*
7823          * we add in the count of missing devices because we want
7824          * to make sure that any RAID levels on a degraded FS
7825          * continue to be honored.
7826          */
7827         num_devices = root->fs_info->fs_devices->rw_devices +
7828                 root->fs_info->fs_devices->missing_devices;
7829
7830         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7831                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
7832                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7833
7834         if (num_devices == 1) {
7835                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7836                 stripped = flags & ~stripped;
7837
7838                 /* turn raid0 into single device chunks */
7839                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7840                         return stripped;
7841
7842                 /* turn mirroring into duplication */
7843                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7844                              BTRFS_BLOCK_GROUP_RAID10))
7845                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7846         } else {
7847                 /* they already had raid on here, just return */
7848                 if (flags & stripped)
7849                         return flags;
7850
7851                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7852                 stripped = flags & ~stripped;
7853
7854                 /* switch duplicated blocks with raid1 */
7855                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7856                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7857
7858                 /* this is drive concat, leave it alone */
7859         }
7860
7861         return flags;
7862 }
7863
7864 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7865 {
7866         struct btrfs_space_info *sinfo = cache->space_info;
7867         u64 num_bytes;
7868         u64 min_allocable_bytes;
7869         int ret = -ENOSPC;
7870
7871
7872         /*
7873          * We need some metadata space and system metadata space for
7874          * allocating chunks in some corner cases until we force to set
7875          * it to be readonly.
7876          */
7877         if ((sinfo->flags &
7878              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7879             !force)
7880                 min_allocable_bytes = 1 * 1024 * 1024;
7881         else
7882                 min_allocable_bytes = 0;
7883
7884         spin_lock(&sinfo->lock);
7885         spin_lock(&cache->lock);
7886
7887         if (cache->ro) {
7888                 ret = 0;
7889                 goto out;
7890         }
7891
7892         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7893                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7894
7895         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7896             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7897             min_allocable_bytes <= sinfo->total_bytes) {
7898                 sinfo->bytes_readonly += num_bytes;
7899                 cache->ro = 1;
7900                 ret = 0;
7901         }
7902 out:
7903         spin_unlock(&cache->lock);
7904         spin_unlock(&sinfo->lock);
7905         return ret;
7906 }
7907
7908 int btrfs_set_block_group_ro(struct btrfs_root *root,
7909                              struct btrfs_block_group_cache *cache)
7910
7911 {
7912         struct btrfs_trans_handle *trans;
7913         u64 alloc_flags;
7914         int ret;
7915
7916         BUG_ON(cache->ro);
7917
7918         trans = btrfs_join_transaction(root);
7919         if (IS_ERR(trans))
7920                 return PTR_ERR(trans);
7921
7922         alloc_flags = update_block_group_flags(root, cache->flags);
7923         if (alloc_flags != cache->flags) {
7924                 ret = do_chunk_alloc(trans, root, alloc_flags,
7925                                      CHUNK_ALLOC_FORCE);
7926                 if (ret < 0)
7927                         goto out;
7928         }
7929
7930         ret = set_block_group_ro(cache, 0);
7931         if (!ret)
7932                 goto out;
7933         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7934         ret = do_chunk_alloc(trans, root, alloc_flags,
7935                              CHUNK_ALLOC_FORCE);
7936         if (ret < 0)
7937                 goto out;
7938         ret = set_block_group_ro(cache, 0);
7939 out:
7940         btrfs_end_transaction(trans, root);
7941         return ret;
7942 }
7943
7944 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7945                             struct btrfs_root *root, u64 type)
7946 {
7947         u64 alloc_flags = get_alloc_profile(root, type);
7948         return do_chunk_alloc(trans, root, alloc_flags,
7949                               CHUNK_ALLOC_FORCE);
7950 }
7951
7952 /*
7953  * helper to account the unused space of all the readonly block group in the
7954  * list. takes mirrors into account.
7955  */
7956 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7957 {
7958         struct btrfs_block_group_cache *block_group;
7959         u64 free_bytes = 0;
7960         int factor;
7961
7962         list_for_each_entry(block_group, groups_list, list) {
7963                 spin_lock(&block_group->lock);
7964
7965                 if (!block_group->ro) {
7966                         spin_unlock(&block_group->lock);
7967                         continue;
7968                 }
7969
7970                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7971                                           BTRFS_BLOCK_GROUP_RAID10 |
7972                                           BTRFS_BLOCK_GROUP_DUP))
7973                         factor = 2;
7974                 else
7975                         factor = 1;
7976
7977                 free_bytes += (block_group->key.offset -
7978                                btrfs_block_group_used(&block_group->item)) *
7979                                factor;
7980
7981                 spin_unlock(&block_group->lock);
7982         }
7983
7984         return free_bytes;
7985 }
7986
7987 /*
7988  * helper to account the unused space of all the readonly block group in the
7989  * space_info. takes mirrors into account.
7990  */
7991 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7992 {
7993         int i;
7994         u64 free_bytes = 0;
7995
7996         spin_lock(&sinfo->lock);
7997
7998         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7999                 if (!list_empty(&sinfo->block_groups[i]))
8000                         free_bytes += __btrfs_get_ro_block_group_free_space(
8001                                                 &sinfo->block_groups[i]);
8002
8003         spin_unlock(&sinfo->lock);
8004
8005         return free_bytes;
8006 }
8007
8008 void btrfs_set_block_group_rw(struct btrfs_root *root,
8009                               struct btrfs_block_group_cache *cache)
8010 {
8011         struct btrfs_space_info *sinfo = cache->space_info;
8012         u64 num_bytes;
8013
8014         BUG_ON(!cache->ro);
8015
8016         spin_lock(&sinfo->lock);
8017         spin_lock(&cache->lock);
8018         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8019                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8020         sinfo->bytes_readonly -= num_bytes;
8021         cache->ro = 0;
8022         spin_unlock(&cache->lock);
8023         spin_unlock(&sinfo->lock);
8024 }
8025
8026 /*
8027  * checks to see if its even possible to relocate this block group.
8028  *
8029  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8030  * ok to go ahead and try.
8031  */
8032 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8033 {
8034         struct btrfs_block_group_cache *block_group;
8035         struct btrfs_space_info *space_info;
8036         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8037         struct btrfs_device *device;
8038         struct btrfs_trans_handle *trans;
8039         u64 min_free;
8040         u64 dev_min = 1;
8041         u64 dev_nr = 0;
8042         u64 target;
8043         int index;
8044         int full = 0;
8045         int ret = 0;
8046
8047         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8048
8049         /* odd, couldn't find the block group, leave it alone */
8050         if (!block_group)
8051                 return -1;
8052
8053         min_free = btrfs_block_group_used(&block_group->item);
8054
8055         /* no bytes used, we're good */
8056         if (!min_free)
8057                 goto out;
8058
8059         space_info = block_group->space_info;
8060         spin_lock(&space_info->lock);
8061
8062         full = space_info->full;
8063
8064         /*
8065          * if this is the last block group we have in this space, we can't
8066          * relocate it unless we're able to allocate a new chunk below.
8067          *
8068          * Otherwise, we need to make sure we have room in the space to handle
8069          * all of the extents from this block group.  If we can, we're good
8070          */
8071         if ((space_info->total_bytes != block_group->key.offset) &&
8072             (space_info->bytes_used + space_info->bytes_reserved +
8073              space_info->bytes_pinned + space_info->bytes_readonly +
8074              min_free < space_info->total_bytes)) {
8075                 spin_unlock(&space_info->lock);
8076                 goto out;
8077         }
8078         spin_unlock(&space_info->lock);
8079
8080         /*
8081          * ok we don't have enough space, but maybe we have free space on our
8082          * devices to allocate new chunks for relocation, so loop through our
8083          * alloc devices and guess if we have enough space.  if this block
8084          * group is going to be restriped, run checks against the target
8085          * profile instead of the current one.
8086          */
8087         ret = -1;
8088
8089         /*
8090          * index:
8091          *      0: raid10
8092          *      1: raid1
8093          *      2: dup
8094          *      3: raid0
8095          *      4: single
8096          */
8097         target = get_restripe_target(root->fs_info, block_group->flags);
8098         if (target) {
8099                 index = __get_raid_index(extended_to_chunk(target));
8100         } else {
8101                 /*
8102                  * this is just a balance, so if we were marked as full
8103                  * we know there is no space for a new chunk
8104                  */
8105                 if (full)
8106                         goto out;
8107
8108                 index = get_block_group_index(block_group);
8109         }
8110
8111         if (index == BTRFS_RAID_RAID10) {
8112                 dev_min = 4;
8113                 /* Divide by 2 */
8114                 min_free >>= 1;
8115         } else if (index == BTRFS_RAID_RAID1) {
8116                 dev_min = 2;
8117         } else if (index == BTRFS_RAID_DUP) {
8118                 /* Multiply by 2 */
8119                 min_free <<= 1;
8120         } else if (index == BTRFS_RAID_RAID0) {
8121                 dev_min = fs_devices->rw_devices;
8122                 do_div(min_free, dev_min);
8123         }
8124
8125         /* We need to do this so that we can look at pending chunks */
8126         trans = btrfs_join_transaction(root);
8127         if (IS_ERR(trans)) {
8128                 ret = PTR_ERR(trans);
8129                 goto out;
8130         }
8131
8132         mutex_lock(&root->fs_info->chunk_mutex);
8133         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8134                 u64 dev_offset;
8135
8136                 /*
8137                  * check to make sure we can actually find a chunk with enough
8138                  * space to fit our block group in.
8139                  */
8140                 if (device->total_bytes > device->bytes_used + min_free &&
8141                     !device->is_tgtdev_for_dev_replace) {
8142                         ret = find_free_dev_extent(trans, device, min_free,
8143                                                    &dev_offset, NULL);
8144                         if (!ret)
8145                                 dev_nr++;
8146
8147                         if (dev_nr >= dev_min)
8148                                 break;
8149
8150                         ret = -1;
8151                 }
8152         }
8153         mutex_unlock(&root->fs_info->chunk_mutex);
8154         btrfs_end_transaction(trans, root);
8155 out:
8156         btrfs_put_block_group(block_group);
8157         return ret;
8158 }
8159
8160 static int find_first_block_group(struct btrfs_root *root,
8161                 struct btrfs_path *path, struct btrfs_key *key)
8162 {
8163         int ret = 0;
8164         struct btrfs_key found_key;
8165         struct extent_buffer *leaf;
8166         int slot;
8167
8168         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
8169         if (ret < 0)
8170                 goto out;
8171
8172         while (1) {
8173                 slot = path->slots[0];
8174                 leaf = path->nodes[0];
8175                 if (slot >= btrfs_header_nritems(leaf)) {
8176                         ret = btrfs_next_leaf(root, path);
8177                         if (ret == 0)
8178                                 continue;
8179                         if (ret < 0)
8180                                 goto out;
8181                         break;
8182                 }
8183                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
8184
8185                 if (found_key.objectid >= key->objectid &&
8186                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
8187                         ret = 0;
8188                         goto out;
8189                 }
8190                 path->slots[0]++;
8191         }
8192 out:
8193         return ret;
8194 }
8195
8196 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
8197 {
8198         struct btrfs_block_group_cache *block_group;
8199         u64 last = 0;
8200
8201         while (1) {
8202                 struct inode *inode;
8203
8204                 block_group = btrfs_lookup_first_block_group(info, last);
8205                 while (block_group) {
8206                         spin_lock(&block_group->lock);
8207                         if (block_group->iref)
8208                                 break;
8209                         spin_unlock(&block_group->lock);
8210                         block_group = next_block_group(info->tree_root,
8211                                                        block_group);
8212                 }
8213                 if (!block_group) {
8214                         if (last == 0)
8215                                 break;
8216                         last = 0;
8217                         continue;
8218                 }
8219
8220                 inode = block_group->inode;
8221                 block_group->iref = 0;
8222                 block_group->inode = NULL;
8223                 spin_unlock(&block_group->lock);
8224                 iput(inode);
8225                 last = block_group->key.objectid + block_group->key.offset;
8226                 btrfs_put_block_group(block_group);
8227         }
8228 }
8229
8230 int btrfs_free_block_groups(struct btrfs_fs_info *info)
8231 {
8232         struct btrfs_block_group_cache *block_group;
8233         struct btrfs_space_info *space_info;
8234         struct btrfs_caching_control *caching_ctl;
8235         struct rb_node *n;
8236
8237         down_write(&info->extent_commit_sem);
8238         while (!list_empty(&info->caching_block_groups)) {
8239                 caching_ctl = list_entry(info->caching_block_groups.next,
8240                                          struct btrfs_caching_control, list);
8241                 list_del(&caching_ctl->list);
8242                 put_caching_control(caching_ctl);
8243         }
8244         up_write(&info->extent_commit_sem);
8245
8246         spin_lock(&info->block_group_cache_lock);
8247         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8248                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8249                                        cache_node);
8250                 rb_erase(&block_group->cache_node,
8251                          &info->block_group_cache_tree);
8252                 spin_unlock(&info->block_group_cache_lock);
8253
8254                 down_write(&block_group->space_info->groups_sem);
8255                 list_del(&block_group->list);
8256                 up_write(&block_group->space_info->groups_sem);
8257
8258                 if (block_group->cached == BTRFS_CACHE_STARTED)
8259                         wait_block_group_cache_done(block_group);
8260
8261                 /*
8262                  * We haven't cached this block group, which means we could
8263                  * possibly have excluded extents on this block group.
8264                  */
8265                 if (block_group->cached == BTRFS_CACHE_NO ||
8266                     block_group->cached == BTRFS_CACHE_ERROR)
8267                         free_excluded_extents(info->extent_root, block_group);
8268
8269                 btrfs_remove_free_space_cache(block_group);
8270                 btrfs_put_block_group(block_group);
8271
8272                 spin_lock(&info->block_group_cache_lock);
8273         }
8274         spin_unlock(&info->block_group_cache_lock);
8275
8276         /* now that all the block groups are freed, go through and
8277          * free all the space_info structs.  This is only called during
8278          * the final stages of unmount, and so we know nobody is
8279          * using them.  We call synchronize_rcu() once before we start,
8280          * just to be on the safe side.
8281          */
8282         synchronize_rcu();
8283
8284         release_global_block_rsv(info);
8285
8286         while(!list_empty(&info->space_info)) {
8287                 space_info = list_entry(info->space_info.next,
8288                                         struct btrfs_space_info,
8289                                         list);
8290                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8291                         if (space_info->bytes_pinned > 0 ||
8292                             space_info->bytes_reserved > 0 ||
8293                             space_info->bytes_may_use > 0) {
8294                                 WARN_ON(1);
8295                                 dump_space_info(space_info, 0, 0);
8296                         }
8297                 }
8298                 percpu_counter_destroy(&space_info->total_bytes_pinned);
8299                 list_del(&space_info->list);
8300                 kfree(space_info);
8301         }
8302         return 0;
8303 }
8304
8305 static void __link_block_group(struct btrfs_space_info *space_info,
8306                                struct btrfs_block_group_cache *cache)
8307 {
8308         int index = get_block_group_index(cache);
8309
8310         down_write(&space_info->groups_sem);
8311         list_add_tail(&cache->list, &space_info->block_groups[index]);
8312         up_write(&space_info->groups_sem);
8313 }
8314
8315 int btrfs_read_block_groups(struct btrfs_root *root)
8316 {
8317         struct btrfs_path *path;
8318         int ret;
8319         struct btrfs_block_group_cache *cache;
8320         struct btrfs_fs_info *info = root->fs_info;
8321         struct btrfs_space_info *space_info;
8322         struct btrfs_key key;
8323         struct btrfs_key found_key;
8324         struct extent_buffer *leaf;
8325         int need_clear = 0;
8326         u64 cache_gen;
8327
8328         root = info->extent_root;
8329         key.objectid = 0;
8330         key.offset = 0;
8331         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
8332         path = btrfs_alloc_path();
8333         if (!path)
8334                 return -ENOMEM;
8335         path->reada = 1;
8336
8337         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
8338         if (btrfs_test_opt(root, SPACE_CACHE) &&
8339             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
8340                 need_clear = 1;
8341         if (btrfs_test_opt(root, CLEAR_CACHE))
8342                 need_clear = 1;
8343
8344         while (1) {
8345                 ret = find_first_block_group(root, path, &key);
8346                 if (ret > 0)
8347                         break;
8348                 if (ret != 0)
8349                         goto error;
8350                 leaf = path->nodes[0];
8351                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8352                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
8353                 if (!cache) {
8354                         ret = -ENOMEM;
8355                         goto error;
8356                 }
8357                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8358                                                 GFP_NOFS);
8359                 if (!cache->free_space_ctl) {
8360                         kfree(cache);
8361                         ret = -ENOMEM;
8362                         goto error;
8363                 }
8364
8365                 atomic_set(&cache->count, 1);
8366                 spin_lock_init(&cache->lock);
8367                 cache->fs_info = info;
8368                 INIT_LIST_HEAD(&cache->list);
8369                 INIT_LIST_HEAD(&cache->cluster_list);
8370
8371                 if (need_clear) {
8372                         /*
8373                          * When we mount with old space cache, we need to
8374                          * set BTRFS_DC_CLEAR and set dirty flag.
8375                          *
8376                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
8377                          *    truncate the old free space cache inode and
8378                          *    setup a new one.
8379                          * b) Setting 'dirty flag' makes sure that we flush
8380                          *    the new space cache info onto disk.
8381                          */
8382                         cache->disk_cache_state = BTRFS_DC_CLEAR;
8383                         if (btrfs_test_opt(root, SPACE_CACHE))
8384                                 cache->dirty = 1;
8385                 }
8386
8387                 read_extent_buffer(leaf, &cache->item,
8388                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
8389                                    sizeof(cache->item));
8390                 memcpy(&cache->key, &found_key, sizeof(found_key));
8391
8392                 key.objectid = found_key.objectid + found_key.offset;
8393                 btrfs_release_path(path);
8394                 cache->flags = btrfs_block_group_flags(&cache->item);
8395                 cache->sectorsize = root->sectorsize;
8396                 cache->full_stripe_len = btrfs_full_stripe_len(root,
8397                                                &root->fs_info->mapping_tree,
8398                                                found_key.objectid);
8399                 btrfs_init_free_space_ctl(cache);
8400
8401                 /*
8402                  * We need to exclude the super stripes now so that the space
8403                  * info has super bytes accounted for, otherwise we'll think
8404                  * we have more space than we actually do.
8405                  */
8406                 ret = exclude_super_stripes(root, cache);
8407                 if (ret) {
8408                         /*
8409                          * We may have excluded something, so call this just in
8410                          * case.
8411                          */
8412                         free_excluded_extents(root, cache);
8413                         kfree(cache->free_space_ctl);
8414                         kfree(cache);
8415                         goto error;
8416                 }
8417
8418                 /*
8419                  * check for two cases, either we are full, and therefore
8420                  * don't need to bother with the caching work since we won't
8421                  * find any space, or we are empty, and we can just add all
8422                  * the space in and be done with it.  This saves us _alot_ of
8423                  * time, particularly in the full case.
8424                  */
8425                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
8426                         cache->last_byte_to_unpin = (u64)-1;
8427                         cache->cached = BTRFS_CACHE_FINISHED;
8428                         free_excluded_extents(root, cache);
8429                 } else if (btrfs_block_group_used(&cache->item) == 0) {
8430                         cache->last_byte_to_unpin = (u64)-1;
8431                         cache->cached = BTRFS_CACHE_FINISHED;
8432                         add_new_free_space(cache, root->fs_info,
8433                                            found_key.objectid,
8434                                            found_key.objectid +
8435                                            found_key.offset);
8436                         free_excluded_extents(root, cache);
8437                 }
8438
8439                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8440                 if (ret) {
8441                         btrfs_remove_free_space_cache(cache);
8442                         btrfs_put_block_group(cache);
8443                         goto error;
8444                 }
8445
8446                 ret = update_space_info(info, cache->flags, found_key.offset,
8447                                         btrfs_block_group_used(&cache->item),
8448                                         &space_info);
8449                 if (ret) {
8450                         btrfs_remove_free_space_cache(cache);
8451                         spin_lock(&info->block_group_cache_lock);
8452                         rb_erase(&cache->cache_node,
8453                                  &info->block_group_cache_tree);
8454                         spin_unlock(&info->block_group_cache_lock);
8455                         btrfs_put_block_group(cache);
8456                         goto error;
8457                 }
8458
8459                 cache->space_info = space_info;
8460                 spin_lock(&cache->space_info->lock);
8461                 cache->space_info->bytes_readonly += cache->bytes_super;
8462                 spin_unlock(&cache->space_info->lock);
8463
8464                 __link_block_group(space_info, cache);
8465
8466                 set_avail_alloc_bits(root->fs_info, cache->flags);
8467                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8468                         set_block_group_ro(cache, 1);
8469         }
8470
8471         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8472                 if (!(get_alloc_profile(root, space_info->flags) &
8473                       (BTRFS_BLOCK_GROUP_RAID10 |
8474                        BTRFS_BLOCK_GROUP_RAID1 |
8475                        BTRFS_BLOCK_GROUP_RAID5 |
8476                        BTRFS_BLOCK_GROUP_RAID6 |
8477                        BTRFS_BLOCK_GROUP_DUP)))
8478                         continue;
8479                 /*
8480                  * avoid allocating from un-mirrored block group if there are
8481                  * mirrored block groups.
8482                  */
8483                 list_for_each_entry(cache,
8484                                 &space_info->block_groups[BTRFS_RAID_RAID0],
8485                                 list)
8486                         set_block_group_ro(cache, 1);
8487                 list_for_each_entry(cache,
8488                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
8489                                 list)
8490                         set_block_group_ro(cache, 1);
8491         }
8492
8493         init_global_block_rsv(info);
8494         ret = 0;
8495 error:
8496         btrfs_free_path(path);
8497         return ret;
8498 }
8499
8500 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
8501                                        struct btrfs_root *root)
8502 {
8503         struct btrfs_block_group_cache *block_group, *tmp;
8504         struct btrfs_root *extent_root = root->fs_info->extent_root;
8505         struct btrfs_block_group_item item;
8506         struct btrfs_key key;
8507         int ret = 0;
8508
8509         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
8510                                  new_bg_list) {
8511                 list_del_init(&block_group->new_bg_list);
8512
8513                 if (ret)
8514                         continue;
8515
8516                 spin_lock(&block_group->lock);
8517                 memcpy(&item, &block_group->item, sizeof(item));
8518                 memcpy(&key, &block_group->key, sizeof(key));
8519                 spin_unlock(&block_group->lock);
8520
8521                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
8522                                         sizeof(item));
8523                 if (ret)
8524                         btrfs_abort_transaction(trans, extent_root, ret);
8525                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
8526                                                key.objectid, key.offset);
8527                 if (ret)
8528                         btrfs_abort_transaction(trans, extent_root, ret);
8529         }
8530 }
8531
8532 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8533                            struct btrfs_root *root, u64 bytes_used,
8534                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8535                            u64 size)
8536 {
8537         int ret;
8538         struct btrfs_root *extent_root;
8539         struct btrfs_block_group_cache *cache;
8540
8541         extent_root = root->fs_info->extent_root;
8542
8543         root->fs_info->last_trans_log_full_commit = trans->transid;
8544
8545         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8546         if (!cache)
8547                 return -ENOMEM;
8548         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8549                                         GFP_NOFS);
8550         if (!cache->free_space_ctl) {
8551                 kfree(cache);
8552                 return -ENOMEM;
8553         }
8554
8555         cache->key.objectid = chunk_offset;
8556         cache->key.offset = size;
8557         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8558         cache->sectorsize = root->sectorsize;
8559         cache->fs_info = root->fs_info;
8560         cache->full_stripe_len = btrfs_full_stripe_len(root,
8561                                                &root->fs_info->mapping_tree,
8562                                                chunk_offset);
8563
8564         atomic_set(&cache->count, 1);
8565         spin_lock_init(&cache->lock);
8566         INIT_LIST_HEAD(&cache->list);
8567         INIT_LIST_HEAD(&cache->cluster_list);
8568         INIT_LIST_HEAD(&cache->new_bg_list);
8569
8570         btrfs_init_free_space_ctl(cache);
8571
8572         btrfs_set_block_group_used(&cache->item, bytes_used);
8573         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8574         cache->flags = type;
8575         btrfs_set_block_group_flags(&cache->item, type);
8576
8577         cache->last_byte_to_unpin = (u64)-1;
8578         cache->cached = BTRFS_CACHE_FINISHED;
8579         ret = exclude_super_stripes(root, cache);
8580         if (ret) {
8581                 /*
8582                  * We may have excluded something, so call this just in
8583                  * case.
8584                  */
8585                 free_excluded_extents(root, cache);
8586                 kfree(cache->free_space_ctl);
8587                 kfree(cache);
8588                 return ret;
8589         }
8590
8591         add_new_free_space(cache, root->fs_info, chunk_offset,
8592                            chunk_offset + size);
8593
8594         free_excluded_extents(root, cache);
8595
8596         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8597         if (ret) {
8598                 btrfs_remove_free_space_cache(cache);
8599                 btrfs_put_block_group(cache);
8600                 return ret;
8601         }
8602
8603         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8604                                 &cache->space_info);
8605         if (ret) {
8606                 btrfs_remove_free_space_cache(cache);
8607                 spin_lock(&root->fs_info->block_group_cache_lock);
8608                 rb_erase(&cache->cache_node,
8609                          &root->fs_info->block_group_cache_tree);
8610                 spin_unlock(&root->fs_info->block_group_cache_lock);
8611                 btrfs_put_block_group(cache);
8612                 return ret;
8613         }
8614         update_global_block_rsv(root->fs_info);
8615
8616         spin_lock(&cache->space_info->lock);
8617         cache->space_info->bytes_readonly += cache->bytes_super;
8618         spin_unlock(&cache->space_info->lock);
8619
8620         __link_block_group(cache->space_info, cache);
8621
8622         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
8623
8624         set_avail_alloc_bits(extent_root->fs_info, type);
8625
8626         return 0;
8627 }
8628
8629 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
8630 {
8631         u64 extra_flags = chunk_to_extended(flags) &
8632                                 BTRFS_EXTENDED_PROFILE_MASK;
8633
8634         write_seqlock(&fs_info->profiles_lock);
8635         if (flags & BTRFS_BLOCK_GROUP_DATA)
8636                 fs_info->avail_data_alloc_bits &= ~extra_flags;
8637         if (flags & BTRFS_BLOCK_GROUP_METADATA)
8638                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
8639         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
8640                 fs_info->avail_system_alloc_bits &= ~extra_flags;
8641         write_sequnlock(&fs_info->profiles_lock);
8642 }
8643
8644 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8645                              struct btrfs_root *root, u64 group_start)
8646 {
8647         struct btrfs_path *path;
8648         struct btrfs_block_group_cache *block_group;
8649         struct btrfs_free_cluster *cluster;
8650         struct btrfs_root *tree_root = root->fs_info->tree_root;
8651         struct btrfs_key key;
8652         struct inode *inode;
8653         int ret;
8654         int index;
8655         int factor;
8656
8657         root = root->fs_info->extent_root;
8658
8659         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8660         BUG_ON(!block_group);
8661         BUG_ON(!block_group->ro);
8662
8663         /*
8664          * Free the reserved super bytes from this block group before
8665          * remove it.
8666          */
8667         free_excluded_extents(root, block_group);
8668
8669         memcpy(&key, &block_group->key, sizeof(key));
8670         index = get_block_group_index(block_group);
8671         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
8672                                   BTRFS_BLOCK_GROUP_RAID1 |
8673                                   BTRFS_BLOCK_GROUP_RAID10))
8674                 factor = 2;
8675         else
8676                 factor = 1;
8677
8678         /* make sure this block group isn't part of an allocation cluster */
8679         cluster = &root->fs_info->data_alloc_cluster;
8680         spin_lock(&cluster->refill_lock);
8681         btrfs_return_cluster_to_free_space(block_group, cluster);
8682         spin_unlock(&cluster->refill_lock);
8683
8684         /*
8685          * make sure this block group isn't part of a metadata
8686          * allocation cluster
8687          */
8688         cluster = &root->fs_info->meta_alloc_cluster;
8689         spin_lock(&cluster->refill_lock);
8690         btrfs_return_cluster_to_free_space(block_group, cluster);
8691         spin_unlock(&cluster->refill_lock);
8692
8693         path = btrfs_alloc_path();
8694         if (!path) {
8695                 ret = -ENOMEM;
8696                 goto out;
8697         }
8698
8699         inode = lookup_free_space_inode(tree_root, block_group, path);
8700         if (!IS_ERR(inode)) {
8701                 ret = btrfs_orphan_add(trans, inode);
8702                 if (ret) {
8703                         btrfs_add_delayed_iput(inode);
8704                         goto out;
8705                 }
8706                 clear_nlink(inode);
8707                 /* One for the block groups ref */
8708                 spin_lock(&block_group->lock);
8709                 if (block_group->iref) {
8710                         block_group->iref = 0;
8711                         block_group->inode = NULL;
8712                         spin_unlock(&block_group->lock);
8713                         iput(inode);
8714                 } else {
8715                         spin_unlock(&block_group->lock);
8716                 }
8717                 /* One for our lookup ref */
8718                 btrfs_add_delayed_iput(inode);
8719         }
8720
8721         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8722         key.offset = block_group->key.objectid;
8723         key.type = 0;
8724
8725         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8726         if (ret < 0)
8727                 goto out;
8728         if (ret > 0)
8729                 btrfs_release_path(path);
8730         if (ret == 0) {
8731                 ret = btrfs_del_item(trans, tree_root, path);
8732                 if (ret)
8733                         goto out;
8734                 btrfs_release_path(path);
8735         }
8736
8737         spin_lock(&root->fs_info->block_group_cache_lock);
8738         rb_erase(&block_group->cache_node,
8739                  &root->fs_info->block_group_cache_tree);
8740
8741         if (root->fs_info->first_logical_byte == block_group->key.objectid)
8742                 root->fs_info->first_logical_byte = (u64)-1;
8743         spin_unlock(&root->fs_info->block_group_cache_lock);
8744
8745         down_write(&block_group->space_info->groups_sem);
8746         /*
8747          * we must use list_del_init so people can check to see if they
8748          * are still on the list after taking the semaphore
8749          */
8750         list_del_init(&block_group->list);
8751         if (list_empty(&block_group->space_info->block_groups[index]))
8752                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8753         up_write(&block_group->space_info->groups_sem);
8754
8755         if (block_group->cached == BTRFS_CACHE_STARTED)
8756                 wait_block_group_cache_done(block_group);
8757
8758         btrfs_remove_free_space_cache(block_group);
8759
8760         spin_lock(&block_group->space_info->lock);
8761         block_group->space_info->total_bytes -= block_group->key.offset;
8762         block_group->space_info->bytes_readonly -= block_group->key.offset;
8763         block_group->space_info->disk_total -= block_group->key.offset * factor;
8764         spin_unlock(&block_group->space_info->lock);
8765
8766         memcpy(&key, &block_group->key, sizeof(key));
8767
8768         btrfs_clear_space_info_full(root->fs_info);
8769
8770         btrfs_put_block_group(block_group);
8771         btrfs_put_block_group(block_group);
8772
8773         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8774         if (ret > 0)
8775                 ret = -EIO;
8776         if (ret < 0)
8777                 goto out;
8778
8779         ret = btrfs_del_item(trans, root, path);
8780 out:
8781         btrfs_free_path(path);
8782         return ret;
8783 }
8784
8785 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8786 {
8787         struct btrfs_space_info *space_info;
8788         struct btrfs_super_block *disk_super;
8789         u64 features;
8790         u64 flags;
8791         int mixed = 0;
8792         int ret;
8793
8794         disk_super = fs_info->super_copy;
8795         if (!btrfs_super_root(disk_super))
8796                 return 1;
8797
8798         features = btrfs_super_incompat_flags(disk_super);
8799         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8800                 mixed = 1;
8801
8802         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8803         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8804         if (ret)
8805                 goto out;
8806
8807         if (mixed) {
8808                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8809                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8810         } else {
8811                 flags = BTRFS_BLOCK_GROUP_METADATA;
8812                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8813                 if (ret)
8814                         goto out;
8815
8816                 flags = BTRFS_BLOCK_GROUP_DATA;
8817                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8818         }
8819 out:
8820         return ret;
8821 }
8822
8823 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8824 {
8825         return unpin_extent_range(root, start, end);
8826 }
8827
8828 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8829                                u64 num_bytes, u64 *actual_bytes)
8830 {
8831         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8832 }
8833
8834 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8835 {
8836         struct btrfs_fs_info *fs_info = root->fs_info;
8837         struct btrfs_block_group_cache *cache = NULL;
8838         u64 group_trimmed;
8839         u64 start;
8840         u64 end;
8841         u64 trimmed = 0;
8842         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8843         int ret = 0;
8844
8845         /*
8846          * try to trim all FS space, our block group may start from non-zero.
8847          */
8848         if (range->len == total_bytes)
8849                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8850         else
8851                 cache = btrfs_lookup_block_group(fs_info, range->start);
8852
8853         while (cache) {
8854                 if (cache->key.objectid >= (range->start + range->len)) {
8855                         btrfs_put_block_group(cache);
8856                         break;
8857                 }
8858
8859                 start = max(range->start, cache->key.objectid);
8860                 end = min(range->start + range->len,
8861                                 cache->key.objectid + cache->key.offset);
8862
8863                 if (end - start >= range->minlen) {
8864                         if (!block_group_cache_done(cache)) {
8865                                 ret = cache_block_group(cache, 0);
8866                                 if (ret) {
8867                                         btrfs_put_block_group(cache);
8868                                         break;
8869                                 }
8870                                 ret = wait_block_group_cache_done(cache);
8871                                 if (ret) {
8872                                         btrfs_put_block_group(cache);
8873                                         break;
8874                                 }
8875                         }
8876                         ret = btrfs_trim_block_group(cache,
8877                                                      &group_trimmed,
8878                                                      start,
8879                                                      end,
8880                                                      range->minlen);
8881
8882                         trimmed += group_trimmed;
8883                         if (ret) {
8884                                 btrfs_put_block_group(cache);
8885                                 break;
8886                         }
8887                 }
8888
8889                 cache = next_block_group(fs_info->tree_root, cache);
8890         }
8891
8892         range->len = trimmed;
8893         return ret;
8894 }