fs/btrfs/extent-tree.c

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