fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/percpu_counter.h>
  28 #include "compat.h"
  29 #include "hash.h"
  30 #include "ctree.h"
  31 #include "disk-io.h"
  32 #include "print-tree.h"
  33 #include "transaction.h"
  34 #include "volumes.h"
  35 #include "raid56.h"
  36 #include "locking.h"
  37 #include "free-space-cache.h"
  38 #include "math.h"
  39
  40 #undef SCRAMBLE_DELAYED_REFS
  41
  42 /*
  43  * control flags for do_chunk_alloc's force field
  44  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  45  * if we really need one.
  46  *
  47  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  48  * if we have very few chunks already allocated.  This is
  49  * used as part of the clustering code to help make sure
  50  * we have a good pool of storage to cluster in, without
  51  * filling the FS with empty chunks
  52  *
  53  * CHUNK_ALLOC_FORCE means it must try to allocate one
  54  *
  55  */
  56 enum {
  57         CHUNK_ALLOC_NO_FORCE = 0,
  58         CHUNK_ALLOC_LIMITED = 1,
  59         CHUNK_ALLOC_FORCE = 2,
  60 };
  61
  62 /*
  63  * Control how reservations are dealt with.
  64  *
  65  * RESERVE_FREE - freeing a reservation.
  66  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  67  *   ENOSPC accounting
  68  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  69  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  70  */
  71 enum {
  72         RESERVE_FREE = 0,
  73         RESERVE_ALLOC = 1,
  74         RESERVE_ALLOC_NO_ACCOUNT = 2,
  75 };
  76
  77 static int update_block_group(struct btrfs_root *root,
  78                               u64 bytenr, u64 num_bytes, int alloc);
  79 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  80                                 struct btrfs_root *root,
  81                                 u64 bytenr, u64 num_bytes, u64 parent,
  82                                 u64 root_objectid, u64 owner_objectid,
  83                                 u64 owner_offset, int refs_to_drop,
  84                                 struct btrfs_delayed_extent_op *extra_op);
  85 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  86                                     struct extent_buffer *leaf,
  87                                     struct btrfs_extent_item *ei);
  88 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  89                                       struct btrfs_root *root,
  90                                       u64 parent, u64 root_objectid,
  91                                       u64 flags, u64 owner, u64 offset,
  92                                       struct btrfs_key *ins, int ref_mod);
  93 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  94                                      struct btrfs_root *root,
  95                                      u64 parent, u64 root_objectid,
  96                                      u64 flags, struct btrfs_disk_key *key,
  97                                      int level, struct btrfs_key *ins);
  98 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  99                           struct btrfs_root *extent_root, u64 flags,
 100                           int force);
 101 static int find_next_key(struct btrfs_path *path, int level,
 102                          struct btrfs_key *key);
 103 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 104                             int dump_block_groups);
 105 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 106                                        u64 num_bytes, int reserve);
 107 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 108                                u64 num_bytes);
 109 int btrfs_pin_extent(struct btrfs_root *root,
 110                      u64 bytenr, u64 num_bytes, int reserved);
 111
 112 static noinline int
 113 block_group_cache_done(struct btrfs_block_group_cache *cache)
 114 {
 115         smp_mb();
 116         return cache->cached == BTRFS_CACHE_FINISHED ||
 117                 cache->cached == BTRFS_CACHE_ERROR;
 118 }
 119
 120 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 121 {
 122         return (cache->flags & bits) == bits;
 123 }
 124
 125 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 126 {
 127         atomic_inc(&cache->count);
 128 }
 129
 130 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 131 {
 132         if (atomic_dec_and_test(&cache->count)) {
 133                 WARN_ON(cache->pinned > 0);
 134                 WARN_ON(cache->reserved > 0);
 135                 kfree(cache->free_space_ctl);
 136                 kfree(cache);
 137         }
 138 }
 139
 140 /*
 141  * this adds the block group to the fs_info rb tree for the block group
 142  * cache
 143  */
 144 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 145                                 struct btrfs_block_group_cache *block_group)
 146 {
 147         struct rb_node **p;
 148         struct rb_node *parent = NULL;
 149         struct btrfs_block_group_cache *cache;
 150
 151         spin_lock(&info->block_group_cache_lock);
 152         p = &info->block_group_cache_tree.rb_node;
 153
 154         while (*p) {
 155                 parent = *p;
 156                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 157                                  cache_node);
 158                 if (block_group->key.objectid < cache->key.objectid) {
 159                         p = &(*p)->rb_left;
 160                 } else if (block_group->key.objectid > cache->key.objectid) {
 161                         p = &(*p)->rb_right;
 162                 } else {
 163                         spin_unlock(&info->block_group_cache_lock);
 164                         return -EEXIST;
 165                 }
 166         }
 167
 168         rb_link_node(&block_group->cache_node, parent, p);
 169         rb_insert_color(&block_group->cache_node,
 170                         &info->block_group_cache_tree);
 171
 172         if (info->first_logical_byte > block_group->key.objectid)
 173                 info->first_logical_byte = block_group->key.objectid;
 174
 175         spin_unlock(&info->block_group_cache_lock);
 176
 177         return 0;
 178 }
 179
 180 /*
 181  * This will return the block group at or after bytenr if contains is 0, else
 182  * it will return the block group that contains the bytenr
 183  */
 184 static struct btrfs_block_group_cache *
 185 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 186                               int contains)
 187 {
 188         struct btrfs_block_group_cache *cache, *ret = NULL;
 189         struct rb_node *n;
 190         u64 end, start;
 191
 192         spin_lock(&info->block_group_cache_lock);
 193         n = info->block_group_cache_tree.rb_node;
 194
 195         while (n) {
 196                 cache = rb_entry(n, struct btrfs_block_group_cache,
 197                                  cache_node);
 198                 end = cache->key.objectid + cache->key.offset - 1;
 199                 start = cache->key.objectid;
 200
 201                 if (bytenr < start) {
 202                         if (!contains && (!ret || start < ret->key.objectid))
 203                                 ret = cache;
 204                         n = n->rb_left;
 205                 } else if (bytenr > start) {
 206                         if (contains && bytenr <= end) {
 207                                 ret = cache;
 208                                 break;
 209                         }
 210                         n = n->rb_right;
 211                 } else {
 212                         ret = cache;
 213                         break;
 214                 }
 215         }
 216         if (ret) {
 217                 btrfs_get_block_group(ret);
 218                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 219                         info->first_logical_byte = ret->key.objectid;
 220         }
 221         spin_unlock(&info->block_group_cache_lock);
 222
 223         return ret;
 224 }
 225
 226 static int add_excluded_extent(struct btrfs_root *root,
 227                                u64 start, u64 num_bytes)
 228 {
 229         u64 end = start + num_bytes - 1;
 230         set_extent_bits(&root->fs_info->freed_extents[0],
 231                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 232         set_extent_bits(&root->fs_info->freed_extents[1],
 233                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 234         return 0;
 235 }
 236
 237 static void free_excluded_extents(struct btrfs_root *root,
 238                                   struct btrfs_block_group_cache *cache)
 239 {
 240         u64 start, end;
 241
 242         start = cache->key.objectid;
 243         end = start + cache->key.offset - 1;
 244
 245         clear_extent_bits(&root->fs_info->freed_extents[0],
 246                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 247         clear_extent_bits(&root->fs_info->freed_extents[1],
 248                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 249 }
 250
 251 static int exclude_super_stripes(struct btrfs_root *root,
 252                                  struct btrfs_block_group_cache *cache)
 253 {
 254         u64 bytenr;
 255         u64 *logical;
 256         int stripe_len;
 257         int i, nr, ret;
 258
 259         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 260                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 261                 cache->bytes_super += stripe_len;
 262                 ret = add_excluded_extent(root, cache->key.objectid,
 263                                           stripe_len);
 264                 if (ret)
 265                         return ret;
 266         }
 267
 268         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 269                 bytenr = btrfs_sb_offset(i);
 270                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 271                                        cache->key.objectid, bytenr,
 272                                        0, &logical, &nr, &stripe_len);
 273                 if (ret)
 274                         return ret;
 275
 276                 while (nr--) {
 277                         u64 start, len;
 278
 279                         if (logical[nr] > cache->key.objectid +
 280                             cache->key.offset)
 281                                 continue;
 282
 283                         if (logical[nr] + stripe_len <= cache->key.objectid)
 284                                 continue;
 285
 286                         start = logical[nr];
 287                         if (start < cache->key.objectid) {
 288                                 start = cache->key.objectid;
 289                                 len = (logical[nr] + stripe_len) - start;
 290                         } else {
 291                                 len = min_t(u64, stripe_len,
 292                                             cache->key.objectid +
 293                                             cache->key.offset - start);
 294                         }
 295
 296                         cache->bytes_super += len;
 297                         ret = add_excluded_extent(root, start, len);
 298                         if (ret) {
 299                                 kfree(logical);
 300                                 return ret;
 301                         }
 302                 }
 303
 304                 kfree(logical);
 305         }
 306         return 0;
 307 }
 308
 309 static struct btrfs_caching_control *
 310 get_caching_control(struct btrfs_block_group_cache *cache)
 311 {
 312         struct btrfs_caching_control *ctl;
 313
 314         spin_lock(&cache->lock);
 315         if (cache->cached != BTRFS_CACHE_STARTED) {
 316                 spin_unlock(&cache->lock);
 317                 return NULL;
 318         }
 319
 320         /* We're loading it the fast way, so we don't have a caching_ctl. */
 321         if (!cache->caching_ctl) {
 322                 spin_unlock(&cache->lock);
 323                 return NULL;
 324         }
 325
 326         ctl = cache->caching_ctl;
 327         atomic_inc(&ctl->count);
 328         spin_unlock(&cache->lock);
 329         return ctl;
 330 }
 331
 332 static void put_caching_control(struct btrfs_caching_control *ctl)
 333 {
 334         if (atomic_dec_and_test(&ctl->count))
 335                 kfree(ctl);
 336 }
 337
 338 /*
 339  * this is only called by cache_block_group, since we could have freed extents
 340  * we need to check the pinned_extents for any extents that can't be used yet
 341  * since their free space will be released as soon as the transaction commits.
 342  */
 343 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 344                               struct btrfs_fs_info *info, u64 start, u64 end)
 345 {
 346         u64 extent_start, extent_end, size, total_added = 0;
 347         int ret;
 348
 349         while (start < end) {
 350                 ret = find_first_extent_bit(info->pinned_extents, start,
 351                                             &extent_start, &extent_end,
 352                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 353                                             NULL);
 354                 if (ret)
 355                         break;
 356
 357                 if (extent_start <= start) {
 358                         start = extent_end + 1;
 359                 } else if (extent_start > start && extent_start < end) {
 360                         size = extent_start - start;
 361                         total_added += size;
 362                         ret = btrfs_add_free_space(block_group, start,
 363                                                    size);
 364                         BUG_ON(ret); /* -ENOMEM or logic error */
 365                         start = extent_end + 1;
 366                 } else {
 367                         break;
 368                 }
 369         }
 370
 371         if (start < end) {
 372                 size = end - start;
 373                 total_added += size;
 374                 ret = btrfs_add_free_space(block_group, start, size);
 375                 BUG_ON(ret); /* -ENOMEM or logic error */
 376         }
 377
 378         return total_added;
 379 }
 380
 381 static noinline void caching_thread(struct btrfs_work *work)
 382 {
 383         struct btrfs_block_group_cache *block_group;
 384         struct btrfs_fs_info *fs_info;
 385         struct btrfs_caching_control *caching_ctl;
 386         struct btrfs_root *extent_root;
 387         struct btrfs_path *path;
 388         struct extent_buffer *leaf;
 389         struct btrfs_key key;
 390         u64 total_found = 0;
 391         u64 last = 0;
 392         u32 nritems;
 393         int ret = -ENOMEM;
 394
 395         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 396         block_group = caching_ctl->block_group;
 397         fs_info = block_group->fs_info;
 398         extent_root = fs_info->extent_root;
 399
 400         path = btrfs_alloc_path();
 401         if (!path)
 402                 goto out;
 403
 404         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 405
 406         /*
 407          * We don't want to deadlock with somebody trying to allocate a new
 408          * extent for the extent root while also trying to search the extent
 409          * root to add free space.  So we skip locking and search the commit
 410          * root, since its read-only
 411          */
 412         path->skip_locking = 1;
 413         path->search_commit_root = 1;
 414         path->reada = 1;
 415
 416         key.objectid = last;
 417         key.offset = 0;
 418         key.type = BTRFS_EXTENT_ITEM_KEY;
 419 again:
 420         mutex_lock(&caching_ctl->mutex);
 421         /* need to make sure the commit_root doesn't disappear */
 422         down_read(&fs_info->extent_commit_sem);
 423
 424 next:
 425         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 426         if (ret < 0)
 427                 goto err;
 428
 429         leaf = path->nodes[0];
 430         nritems = btrfs_header_nritems(leaf);
 431
 432         while (1) {
 433                 if (btrfs_fs_closing(fs_info) > 1) {
 434                         last = (u64)-1;
 435                         break;
 436                 }
 437
 438                 if (path->slots[0] < nritems) {
 439                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 440                 } else {
 441                         ret = find_next_key(path, 0, &key);
 442                         if (ret)
 443                                 break;
 444
 445                         if (need_resched()) {
 446                                 caching_ctl->progress = last;
 447                                 btrfs_release_path(path);
 448                                 up_read(&fs_info->extent_commit_sem);
 449                                 mutex_unlock(&caching_ctl->mutex);
 450                                 cond_resched();
 451                                 goto again;
 452                         }
 453
 454                         ret = btrfs_next_leaf(extent_root, path);
 455                         if (ret < 0)
 456                                 goto err;
 457                         if (ret)
 458                                 break;
 459                         leaf = path->nodes[0];
 460                         nritems = btrfs_header_nritems(leaf);
 461                         continue;
 462                 }
 463
 464                 if (key.objectid < last) {
 465                         key.objectid = last;
 466                         key.offset = 0;
 467                         key.type = BTRFS_EXTENT_ITEM_KEY;
 468
 469                         caching_ctl->progress = last;
 470                         btrfs_release_path(path);
 471                         goto next;
 472                 }
 473
 474                 if (key.objectid < block_group->key.objectid) {
 475                         path->slots[0]++;
 476                         continue;
 477                 }
 478
 479                 if (key.objectid >= block_group->key.objectid +
 480                     block_group->key.offset)
 481                         break;
 482
 483                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 484                     key.type == BTRFS_METADATA_ITEM_KEY) {
 485                         total_found += add_new_free_space(block_group,
 486                                                           fs_info, last,
 487                                                           key.objectid);
 488                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 489                                 last = key.objectid +
 490                                         fs_info->tree_root->leafsize;
 491                         else
 492                                 last = key.objectid + key.offset;
 493
 494                         if (total_found > (1024 * 1024 * 2)) {
 495                                 total_found = 0;
 496                                 wake_up(&caching_ctl->wait);
 497                         }
 498                 }
 499                 path->slots[0]++;
 500         }
 501         ret = 0;
 502
 503         total_found += add_new_free_space(block_group, fs_info, last,
 504                                           block_group->key.objectid +
 505                                           block_group->key.offset);
 506         caching_ctl->progress = (u64)-1;
 507
 508         spin_lock(&block_group->lock);
 509         block_group->caching_ctl = NULL;
 510         block_group->cached = BTRFS_CACHE_FINISHED;
 511         spin_unlock(&block_group->lock);
 512
 513 err:
 514         btrfs_free_path(path);
 515         up_read(&fs_info->extent_commit_sem);
 516
 517         free_excluded_extents(extent_root, block_group);
 518
 519         mutex_unlock(&caching_ctl->mutex);
 520 out:
 521         if (ret) {
 522                 spin_lock(&block_group->lock);
 523                 block_group->caching_ctl = NULL;
 524                 block_group->cached = BTRFS_CACHE_ERROR;
 525                 spin_unlock(&block_group->lock);
 526         }
 527         wake_up(&caching_ctl->wait);
 528
 529         put_caching_control(caching_ctl);
 530         btrfs_put_block_group(block_group);
 531 }
 532
 533 static int cache_block_group(struct btrfs_block_group_cache *cache,
 534                              int load_cache_only)
 535 {
 536         DEFINE_WAIT(wait);
 537         struct btrfs_fs_info *fs_info = cache->fs_info;
 538         struct btrfs_caching_control *caching_ctl;
 539         int ret = 0;
 540
 541         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 542         if (!caching_ctl)
 543                 return -ENOMEM;
 544
 545         INIT_LIST_HEAD(&caching_ctl->list);
 546         mutex_init(&caching_ctl->mutex);
 547         init_waitqueue_head(&caching_ctl->wait);
 548         caching_ctl->block_group = cache;
 549         caching_ctl->progress = cache->key.objectid;
 550         atomic_set(&caching_ctl->count, 1);
 551         caching_ctl->work.func = caching_thread;
 552
 553         spin_lock(&cache->lock);
 554         /*
 555          * This should be a rare occasion, but this could happen I think in the
 556          * case where one thread starts to load the space cache info, and then
 557          * some other thread starts a transaction commit which tries to do an
 558          * allocation while the other thread is still loading the space cache
 559          * info.  The previous loop should have kept us from choosing this block
 560          * group, but if we've moved to the state where we will wait on caching
 561          * block groups we need to first check if we're doing a fast load here,
 562          * so we can wait for it to finish, otherwise we could end up allocating
 563          * from a block group who's cache gets evicted for one reason or
 564          * another.
 565          */
 566         while (cache->cached == BTRFS_CACHE_FAST) {
 567                 struct btrfs_caching_control *ctl;
 568
 569                 ctl = cache->caching_ctl;
 570                 atomic_inc(&ctl->count);
 571                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 572                 spin_unlock(&cache->lock);
 573
 574                 schedule();
 575
 576                 finish_wait(&ctl->wait, &wait);
 577                 put_caching_control(ctl);
 578                 spin_lock(&cache->lock);
 579         }
 580
 581         if (cache->cached != BTRFS_CACHE_NO) {
 582                 spin_unlock(&cache->lock);
 583                 kfree(caching_ctl);
 584                 return 0;
 585         }
 586         WARN_ON(cache->caching_ctl);
 587         cache->caching_ctl = caching_ctl;
 588         cache->cached = BTRFS_CACHE_FAST;
 589         spin_unlock(&cache->lock);
 590
 591         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 592                 ret = load_free_space_cache(fs_info, cache);
 593
 594                 spin_lock(&cache->lock);
 595                 if (ret == 1) {
 596                         cache->caching_ctl = NULL;
 597                         cache->cached = BTRFS_CACHE_FINISHED;
 598                         cache->last_byte_to_unpin = (u64)-1;
 599                 } else {
 600                         if (load_cache_only) {
 601                                 cache->caching_ctl = NULL;
 602                                 cache->cached = BTRFS_CACHE_NO;
 603                         } else {
 604                                 cache->cached = BTRFS_CACHE_STARTED;
 605                         }
 606                 }
 607                 spin_unlock(&cache->lock);
 608                 wake_up(&caching_ctl->wait);
 609                 if (ret == 1) {
 610                         put_caching_control(caching_ctl);
 611                         free_excluded_extents(fs_info->extent_root, cache);
 612                         return 0;
 613                 }
 614         } else {
 615                 /*
 616                  * We are not going to do the fast caching, set cached to the
 617                  * appropriate value and wakeup any waiters.
 618                  */
 619                 spin_lock(&cache->lock);
 620                 if (load_cache_only) {
 621                         cache->caching_ctl = NULL;
 622                         cache->cached = BTRFS_CACHE_NO;
 623                 } else {
 624                         cache->cached = BTRFS_CACHE_STARTED;
 625                 }
 626                 spin_unlock(&cache->lock);
 627                 wake_up(&caching_ctl->wait);
 628         }
 629
 630         if (load_cache_only) {
 631                 put_caching_control(caching_ctl);
 632                 return 0;
 633         }
 634
 635         down_write(&fs_info->extent_commit_sem);
 636         atomic_inc(&caching_ctl->count);
 637         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 638         up_write(&fs_info->extent_commit_sem);
 639
 640         btrfs_get_block_group(cache);
 641
 642         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 643
 644         return ret;
 645 }
 646
 647 /*
 648  * return the block group that starts at or after bytenr
 649  */
 650 static struct btrfs_block_group_cache *
 651 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 652 {
 653         struct btrfs_block_group_cache *cache;
 654
 655         cache = block_group_cache_tree_search(info, bytenr, 0);
 656
 657         return cache;
 658 }
 659
 660 /*
 661  * return the block group that contains the given bytenr
 662  */
 663 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 664                                                  struct btrfs_fs_info *info,
 665                                                  u64 bytenr)
 666 {
 667         struct btrfs_block_group_cache *cache;
 668
 669         cache = block_group_cache_tree_search(info, bytenr, 1);
 670
 671         return cache;
 672 }
 673
 674 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 675                                                   u64 flags)
 676 {
 677         struct list_head *head = &info->space_info;
 678         struct btrfs_space_info *found;
 679
 680         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 681
 682         rcu_read_lock();
 683         list_for_each_entry_rcu(found, head, list) {
 684                 if (found->flags & flags) {
 685                         rcu_read_unlock();
 686                         return found;
 687                 }
 688         }
 689         rcu_read_unlock();
 690         return NULL;
 691 }
 692
 693 /*
 694  * after adding space to the filesystem, we need to clear the full flags
 695  * on all the space infos.
 696  */
 697 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 698 {
 699         struct list_head *head = &info->space_info;
 700         struct btrfs_space_info *found;
 701
 702         rcu_read_lock();
 703         list_for_each_entry_rcu(found, head, list)
 704                 found->full = 0;
 705         rcu_read_unlock();
 706 }
 707
 708 /* simple helper to search for an existing extent at a given offset */
 709 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 710 {
 711         int ret;
 712         struct btrfs_key key;
 713         struct btrfs_path *path;
 714
 715         path = btrfs_alloc_path();
 716         if (!path)
 717                 return -ENOMEM;
 718
 719         key.objectid = start;
 720         key.offset = len;
 721         key.type = BTRFS_EXTENT_ITEM_KEY;
 722         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 723                                 0, 0);
 724         if (ret > 0) {
 725                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 726                 if (key.objectid == start &&
 727                     key.type == BTRFS_METADATA_ITEM_KEY)
 728                         ret = 0;
 729         }
 730         btrfs_free_path(path);
 731         return ret;
 732 }
 733
 734 /*
 735  * helper function to lookup reference count and flags of a tree block.
 736  *
 737  * the head node for delayed ref is used to store the sum of all the
 738  * reference count modifications queued up in the rbtree. the head
 739  * node may also store the extent flags to set. This way you can check
 740  * to see what the reference count and extent flags would be if all of
 741  * the delayed refs are not processed.
 742  */
 743 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 744                              struct btrfs_root *root, u64 bytenr,
 745                              u64 offset, int metadata, u64 *refs, u64 *flags)
 746 {
 747         struct btrfs_delayed_ref_head *head;
 748         struct btrfs_delayed_ref_root *delayed_refs;
 749         struct btrfs_path *path;
 750         struct btrfs_extent_item *ei;
 751         struct extent_buffer *leaf;
 752         struct btrfs_key key;
 753         u32 item_size;
 754         u64 num_refs;
 755         u64 extent_flags;
 756         int ret;
 757
 758         /*
 759          * If we don't have skinny metadata, don't bother doing anything
 760          * different
 761          */
 762         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 763                 offset = root->leafsize;
 764                 metadata = 0;
 765         }
 766
 767         path = btrfs_alloc_path();
 768         if (!path)
 769                 return -ENOMEM;
 770
 771         if (metadata) {
 772                 key.objectid = bytenr;
 773                 key.type = BTRFS_METADATA_ITEM_KEY;
 774                 key.offset = offset;
 775         } else {
 776                 key.objectid = bytenr;
 777                 key.type = BTRFS_EXTENT_ITEM_KEY;
 778                 key.offset = offset;
 779         }
 780
 781         if (!trans) {
 782                 path->skip_locking = 1;
 783                 path->search_commit_root = 1;
 784         }
 785 again:
 786         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 787                                 &key, path, 0, 0);
 788         if (ret < 0)
 789                 goto out_free;
 790
 791         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 792                 metadata = 0;
 793                 if (path->slots[0]) {
 794                         path->slots[0]--;
 795                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 796                                               path->slots[0]);
 797                         if (key.objectid == bytenr &&
 798                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 799                             key.offset == root->leafsize)
 800                                 ret = 0;
 801                 }
 802                 if (ret) {
 803                         key.objectid = bytenr;
 804                         key.type = BTRFS_EXTENT_ITEM_KEY;
 805                         key.offset = root->leafsize;
 806                         btrfs_release_path(path);
 807                         goto again;
 808                 }
 809         }
 810
 811         if (ret == 0) {
 812                 leaf = path->nodes[0];
 813                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 814                 if (item_size >= sizeof(*ei)) {
 815                         ei = btrfs_item_ptr(leaf, path->slots[0],
 816                                             struct btrfs_extent_item);
 817                         num_refs = btrfs_extent_refs(leaf, ei);
 818                         extent_flags = btrfs_extent_flags(leaf, ei);
 819                 } else {
 820 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 821                         struct btrfs_extent_item_v0 *ei0;
 822                         BUG_ON(item_size != sizeof(*ei0));
 823                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 824                                              struct btrfs_extent_item_v0);
 825                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 826                         /* FIXME: this isn't correct for data */
 827                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 828 #else
 829                         BUG();
 830 #endif
 831                 }
 832                 BUG_ON(num_refs == 0);
 833         } else {
 834                 num_refs = 0;
 835                 extent_flags = 0;
 836                 ret = 0;
 837         }
 838
 839         if (!trans)
 840                 goto out;
 841
 842         delayed_refs = &trans->transaction->delayed_refs;
 843         spin_lock(&delayed_refs->lock);
 844         head = btrfs_find_delayed_ref_head(trans, bytenr);
 845         if (head) {
 846                 if (!mutex_trylock(&head->mutex)) {
 847                         atomic_inc(&head->node.refs);
 848                         spin_unlock(&delayed_refs->lock);
 849
 850                         btrfs_release_path(path);
 851
 852                         /*
 853                          * Mutex was contended, block until it's released and try
 854                          * again
 855                          */
 856                         mutex_lock(&head->mutex);
 857                         mutex_unlock(&head->mutex);
 858                         btrfs_put_delayed_ref(&head->node);
 859                         goto again;
 860                 }
 861                 if (head->extent_op && head->extent_op->update_flags)
 862                         extent_flags |= head->extent_op->flags_to_set;
 863                 else
 864                         BUG_ON(num_refs == 0);
 865
 866                 num_refs += head->node.ref_mod;
 867                 mutex_unlock(&head->mutex);
 868         }
 869         spin_unlock(&delayed_refs->lock);
 870 out:
 871         WARN_ON(num_refs == 0);
 872         if (refs)
 873                 *refs = num_refs;
 874         if (flags)
 875                 *flags = extent_flags;
 876 out_free:
 877         btrfs_free_path(path);
 878         return ret;
 879 }
 880
 881 /*
 882  * Back reference rules.  Back refs have three main goals:
 883  *
 884  * 1) differentiate between all holders of references to an extent so that
 885  *    when a reference is dropped we can make sure it was a valid reference
 886  *    before freeing the extent.
 887  *
 888  * 2) Provide enough information to quickly find the holders of an extent
 889  *    if we notice a given block is corrupted or bad.
 890  *
 891  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 892  *    maintenance.  This is actually the same as #2, but with a slightly
 893  *    different use case.
 894  *
 895  * There are two kinds of back refs. The implicit back refs is optimized
 896  * for pointers in non-shared tree blocks. For a given pointer in a block,
 897  * back refs of this kind provide information about the block's owner tree
 898  * and the pointer's key. These information allow us to find the block by
 899  * b-tree searching. The full back refs is for pointers in tree blocks not
 900  * referenced by their owner trees. The location of tree block is recorded
 901  * in the back refs. Actually the full back refs is generic, and can be
 902  * used in all cases the implicit back refs is used. The major shortcoming
 903  * of the full back refs is its overhead. Every time a tree block gets
 904  * COWed, we have to update back refs entry for all pointers in it.
 905  *
 906  * For a newly allocated tree block, we use implicit back refs for
 907  * pointers in it. This means most tree related operations only involve
 908  * implicit back refs. For a tree block created in old transaction, the
 909  * only way to drop a reference to it is COW it. So we can detect the
 910  * event that tree block loses its owner tree's reference and do the
 911  * back refs conversion.
 912  *
 913  * When a tree block is COW'd through a tree, there are four cases:
 914  *
 915  * The reference count of the block is one and the tree is the block's
 916  * owner tree. Nothing to do in this case.
 917  *
 918  * The reference count of the block is one and the tree is not the
 919  * block's owner tree. In this case, full back refs is used for pointers
 920  * in the block. Remove these full back refs, add implicit back refs for
 921  * every pointers in the new block.
 922  *
 923  * The reference count of the block is greater than one and the tree is
 924  * the block's owner tree. In this case, implicit back refs is used for
 925  * pointers in the block. Add full back refs for every pointers in the
 926  * block, increase lower level extents' reference counts. The original
 927  * implicit back refs are entailed to the new block.
 928  *
 929  * The reference count of the block is greater than one and the tree is
 930  * not the block's owner tree. Add implicit back refs for every pointer in
 931  * the new block, increase lower level extents' reference count.
 932  *
 933  * Back Reference Key composing:
 934  *
 935  * The key objectid corresponds to the first byte in the extent,
 936  * The key type is used to differentiate between types of back refs.
 937  * There are different meanings of the key offset for different types
 938  * of back refs.
 939  *
 940  * File extents can be referenced by:
 941  *
 942  * - multiple snapshots, subvolumes, or different generations in one subvol
 943  * - different files inside a single subvolume
 944  * - different offsets inside a file (bookend extents in file.c)
 945  *
 946  * The extent ref structure for the implicit back refs has fields for:
 947  *
 948  * - Objectid of the subvolume root
 949  * - objectid of the file holding the reference
 950  * - original offset in the file
 951  * - how many bookend extents
 952  *
 953  * The key offset for the implicit back refs is hash of the first
 954  * three fields.
 955  *
 956  * The extent ref structure for the full back refs has field for:
 957  *
 958  * - number of pointers in the tree leaf
 959  *
 960  * The key offset for the implicit back refs is the first byte of
 961  * the tree leaf
 962  *
 963  * When a file extent is allocated, The implicit back refs is used.
 964  * the fields are filled in:
 965  *
 966  *     (root_key.objectid, inode objectid, offset in file, 1)
 967  *
 968  * When a file extent is removed file truncation, we find the
 969  * corresponding implicit back refs and check the following fields:
 970  *
 971  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 972  *
 973  * Btree extents can be referenced by:
 974  *
 975  * - Different subvolumes
 976  *
 977  * Both the implicit back refs and the full back refs for tree blocks
 978  * only consist of key. The key offset for the implicit back refs is
 979  * objectid of block's owner tree. The key offset for the full back refs
 980  * is the first byte of parent block.
 981  *
 982  * When implicit back refs is used, information about the lowest key and
 983  * level of the tree block are required. These information are stored in
 984  * tree block info structure.
 985  */
 986
 987 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 988 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 989                                   struct btrfs_root *root,
 990                                   struct btrfs_path *path,
 991                                   u64 owner, u32 extra_size)
 992 {
 993         struct btrfs_extent_item *item;
 994         struct btrfs_extent_item_v0 *ei0;
 995         struct btrfs_extent_ref_v0 *ref0;
 996         struct btrfs_tree_block_info *bi;
 997         struct extent_buffer *leaf;
 998         struct btrfs_key key;
 999         struct btrfs_key found_key;
1000         u32 new_size = sizeof(*item);
1001         u64 refs;
1002         int ret;
1003
1004         leaf = path->nodes[0];
1005         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1006
1007         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1008         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1009                              struct btrfs_extent_item_v0);
1010         refs = btrfs_extent_refs_v0(leaf, ei0);
1011
1012         if (owner == (u64)-1) {
1013                 while (1) {
1014                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1015                                 ret = btrfs_next_leaf(root, path);
1016                                 if (ret < 0)
1017                                         return ret;
1018                                 BUG_ON(ret > 0); /* Corruption */
1019                                 leaf = path->nodes[0];
1020                         }
1021                         btrfs_item_key_to_cpu(leaf, &found_key,
1022                                               path->slots[0]);
1023                         BUG_ON(key.objectid != found_key.objectid);
1024                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1025                                 path->slots[0]++;
1026                                 continue;
1027                         }
1028                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1029                                               struct btrfs_extent_ref_v0);
1030                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1031                         break;
1032                 }
1033         }
1034         btrfs_release_path(path);
1035
1036         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1037                 new_size += sizeof(*bi);
1038
1039         new_size -= sizeof(*ei0);
1040         ret = btrfs_search_slot(trans, root, &key, path,
1041                                 new_size + extra_size, 1);
1042         if (ret < 0)
1043                 return ret;
1044         BUG_ON(ret); /* Corruption */
1045
1046         btrfs_extend_item(root, path, new_size);
1047
1048         leaf = path->nodes[0];
1049         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1050         btrfs_set_extent_refs(leaf, item, refs);
1051         /* FIXME: get real generation */
1052         btrfs_set_extent_generation(leaf, item, 0);
1053         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1054                 btrfs_set_extent_flags(leaf, item,
1055                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1056                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1057                 bi = (struct btrfs_tree_block_info *)(item + 1);
1058                 /* FIXME: get first key of the block */
1059                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1060                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1061         } else {
1062                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1063         }
1064         btrfs_mark_buffer_dirty(leaf);
1065         return 0;
1066 }
1067 #endif
1068
1069 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1070 {
1071         u32 high_crc = ~(u32)0;
1072         u32 low_crc = ~(u32)0;
1073         __le64 lenum;
1074
1075         lenum = cpu_to_le64(root_objectid);
1076         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1077         lenum = cpu_to_le64(owner);
1078         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1079         lenum = cpu_to_le64(offset);
1080         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1081
1082         return ((u64)high_crc << 31) ^ (u64)low_crc;
1083 }
1084
1085 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1086                                      struct btrfs_extent_data_ref *ref)
1087 {
1088         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1089                                     btrfs_extent_data_ref_objectid(leaf, ref),
1090                                     btrfs_extent_data_ref_offset(leaf, ref));
1091 }
1092
1093 static int match_extent_data_ref(struct extent_buffer *leaf,
1094                                  struct btrfs_extent_data_ref *ref,
1095                                  u64 root_objectid, u64 owner, u64 offset)
1096 {
1097         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1098             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1099             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1100                 return 0;
1101         return 1;
1102 }
1103
1104 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1105                                            struct btrfs_root *root,
1106                                            struct btrfs_path *path,
1107                                            u64 bytenr, u64 parent,
1108                                            u64 root_objectid,
1109                                            u64 owner, u64 offset)
1110 {
1111         struct btrfs_key key;
1112         struct btrfs_extent_data_ref *ref;
1113         struct extent_buffer *leaf;
1114         u32 nritems;
1115         int ret;
1116         int recow;
1117         int err = -ENOENT;
1118
1119         key.objectid = bytenr;
1120         if (parent) {
1121                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1122                 key.offset = parent;
1123         } else {
1124                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1125                 key.offset = hash_extent_data_ref(root_objectid,
1126                                                   owner, offset);
1127         }
1128 again:
1129         recow = 0;
1130         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1131         if (ret < 0) {
1132                 err = ret;
1133                 goto fail;
1134         }
1135
1136         if (parent) {
1137                 if (!ret)
1138                         return 0;
1139 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1140                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1141                 btrfs_release_path(path);
1142                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1143                 if (ret < 0) {
1144                         err = ret;
1145                         goto fail;
1146                 }
1147                 if (!ret)
1148                         return 0;
1149 #endif
1150                 goto fail;
1151         }
1152
1153         leaf = path->nodes[0];
1154         nritems = btrfs_header_nritems(leaf);
1155         while (1) {
1156                 if (path->slots[0] >= nritems) {
1157                         ret = btrfs_next_leaf(root, path);
1158                         if (ret < 0)
1159                                 err = ret;
1160                         if (ret)
1161                                 goto fail;
1162
1163                         leaf = path->nodes[0];
1164                         nritems = btrfs_header_nritems(leaf);
1165                         recow = 1;
1166                 }
1167
1168                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1169                 if (key.objectid != bytenr ||
1170                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1171                         goto fail;
1172
1173                 ref = btrfs_item_ptr(leaf, path->slots[0],
1174                                      struct btrfs_extent_data_ref);
1175
1176                 if (match_extent_data_ref(leaf, ref, root_objectid,
1177                                           owner, offset)) {
1178                         if (recow) {
1179                                 btrfs_release_path(path);
1180                                 goto again;
1181                         }
1182                         err = 0;
1183                         break;
1184                 }
1185                 path->slots[0]++;
1186         }
1187 fail:
1188         return err;
1189 }
1190
1191 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1192                                            struct btrfs_root *root,
1193                                            struct btrfs_path *path,
1194                                            u64 bytenr, u64 parent,
1195                                            u64 root_objectid, u64 owner,
1196                                            u64 offset, int refs_to_add)
1197 {
1198         struct btrfs_key key;
1199         struct extent_buffer *leaf;
1200         u32 size;
1201         u32 num_refs;
1202         int ret;
1203
1204         key.objectid = bytenr;
1205         if (parent) {
1206                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1207                 key.offset = parent;
1208                 size = sizeof(struct btrfs_shared_data_ref);
1209         } else {
1210                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1211                 key.offset = hash_extent_data_ref(root_objectid,
1212                                                   owner, offset);
1213                 size = sizeof(struct btrfs_extent_data_ref);
1214         }
1215
1216         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1217         if (ret && ret != -EEXIST)
1218                 goto fail;
1219
1220         leaf = path->nodes[0];
1221         if (parent) {
1222                 struct btrfs_shared_data_ref *ref;
1223                 ref = btrfs_item_ptr(leaf, path->slots[0],
1224                                      struct btrfs_shared_data_ref);
1225                 if (ret == 0) {
1226                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1227                 } else {
1228                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1229                         num_refs += refs_to_add;
1230                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1231                 }
1232         } else {
1233                 struct btrfs_extent_data_ref *ref;
1234                 while (ret == -EEXIST) {
1235                         ref = btrfs_item_ptr(leaf, path->slots[0],
1236                                              struct btrfs_extent_data_ref);
1237                         if (match_extent_data_ref(leaf, ref, root_objectid,
1238                                                   owner, offset))
1239                                 break;
1240                         btrfs_release_path(path);
1241                         key.offset++;
1242                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1243                                                       size);
1244                         if (ret && ret != -EEXIST)
1245                                 goto fail;
1246
1247                         leaf = path->nodes[0];
1248                 }
1249                 ref = btrfs_item_ptr(leaf, path->slots[0],
1250                                      struct btrfs_extent_data_ref);
1251                 if (ret == 0) {
1252                         btrfs_set_extent_data_ref_root(leaf, ref,
1253                                                        root_objectid);
1254                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1255                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1256                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1257                 } else {
1258                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1259                         num_refs += refs_to_add;
1260                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1261                 }
1262         }
1263         btrfs_mark_buffer_dirty(leaf);
1264         ret = 0;
1265 fail:
1266         btrfs_release_path(path);
1267         return ret;
1268 }
1269
1270 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1271                                            struct btrfs_root *root,
1272                                            struct btrfs_path *path,
1273                                            int refs_to_drop)
1274 {
1275         struct btrfs_key key;
1276         struct btrfs_extent_data_ref *ref1 = NULL;
1277         struct btrfs_shared_data_ref *ref2 = NULL;
1278         struct extent_buffer *leaf;
1279         u32 num_refs = 0;
1280         int ret = 0;
1281
1282         leaf = path->nodes[0];
1283         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1284
1285         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1286                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1287                                       struct btrfs_extent_data_ref);
1288                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1289         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1290                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1291                                       struct btrfs_shared_data_ref);
1292                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1293 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1294         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1295                 struct btrfs_extent_ref_v0 *ref0;
1296                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1297                                       struct btrfs_extent_ref_v0);
1298                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1299 #endif
1300         } else {
1301                 BUG();
1302         }
1303
1304         BUG_ON(num_refs < refs_to_drop);
1305         num_refs -= refs_to_drop;
1306
1307         if (num_refs == 0) {
1308                 ret = btrfs_del_item(trans, root, path);
1309         } else {
1310                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1311                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1312                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1313                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1314 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1315                 else {
1316                         struct btrfs_extent_ref_v0 *ref0;
1317                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1318                                         struct btrfs_extent_ref_v0);
1319                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1320                 }
1321 #endif
1322                 btrfs_mark_buffer_dirty(leaf);
1323         }
1324         return ret;
1325 }
1326
1327 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1328                                           struct btrfs_path *path,
1329                                           struct btrfs_extent_inline_ref *iref)
1330 {
1331         struct btrfs_key key;
1332         struct extent_buffer *leaf;
1333         struct btrfs_extent_data_ref *ref1;
1334         struct btrfs_shared_data_ref *ref2;
1335         u32 num_refs = 0;
1336
1337         leaf = path->nodes[0];
1338         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1339         if (iref) {
1340                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1341                     BTRFS_EXTENT_DATA_REF_KEY) {
1342                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1343                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1344                 } else {
1345                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1346                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1347                 }
1348         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1349                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1350                                       struct btrfs_extent_data_ref);
1351                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1352         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1353                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1354                                       struct btrfs_shared_data_ref);
1355                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1356 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1357         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1358                 struct btrfs_extent_ref_v0 *ref0;
1359                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1360                                       struct btrfs_extent_ref_v0);
1361                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1362 #endif
1363         } else {
1364                 WARN_ON(1);
1365         }
1366         return num_refs;
1367 }
1368
1369 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1370                                           struct btrfs_root *root,
1371                                           struct btrfs_path *path,
1372                                           u64 bytenr, u64 parent,
1373                                           u64 root_objectid)
1374 {
1375         struct btrfs_key key;
1376         int ret;
1377
1378         key.objectid = bytenr;
1379         if (parent) {
1380                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1381                 key.offset = parent;
1382         } else {
1383                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1384                 key.offset = root_objectid;
1385         }
1386
1387         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1388         if (ret > 0)
1389                 ret = -ENOENT;
1390 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1391         if (ret == -ENOENT && parent) {
1392                 btrfs_release_path(path);
1393                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1394                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1395                 if (ret > 0)
1396                         ret = -ENOENT;
1397         }
1398 #endif
1399         return ret;
1400 }
1401
1402 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1403                                           struct btrfs_root *root,
1404                                           struct btrfs_path *path,
1405                                           u64 bytenr, u64 parent,
1406                                           u64 root_objectid)
1407 {
1408         struct btrfs_key key;
1409         int ret;
1410
1411         key.objectid = bytenr;
1412         if (parent) {
1413                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1414                 key.offset = parent;
1415         } else {
1416                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1417                 key.offset = root_objectid;
1418         }
1419
1420         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1421         btrfs_release_path(path);
1422         return ret;
1423 }
1424
1425 static inline int extent_ref_type(u64 parent, u64 owner)
1426 {
1427         int type;
1428         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1429                 if (parent > 0)
1430                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1431                 else
1432                         type = BTRFS_TREE_BLOCK_REF_KEY;
1433         } else {
1434                 if (parent > 0)
1435                         type = BTRFS_SHARED_DATA_REF_KEY;
1436                 else
1437                         type = BTRFS_EXTENT_DATA_REF_KEY;
1438         }
1439         return type;
1440 }
1441
1442 static int find_next_key(struct btrfs_path *path, int level,
1443                          struct btrfs_key *key)
1444
1445 {
1446         for (; level < BTRFS_MAX_LEVEL; level++) {
1447                 if (!path->nodes[level])
1448                         break;
1449                 if (path->slots[level] + 1 >=
1450                     btrfs_header_nritems(path->nodes[level]))
1451                         continue;
1452                 if (level == 0)
1453                         btrfs_item_key_to_cpu(path->nodes[level], key,
1454                                               path->slots[level] + 1);
1455                 else
1456                         btrfs_node_key_to_cpu(path->nodes[level], key,
1457                                               path->slots[level] + 1);
1458                 return 0;
1459         }
1460         return 1;
1461 }
1462
1463 /*
1464  * look for inline back ref. if back ref is found, *ref_ret is set
1465  * to the address of inline back ref, and 0 is returned.
1466  *
1467  * if back ref isn't found, *ref_ret is set to the address where it
1468  * should be inserted, and -ENOENT is returned.
1469  *
1470  * if insert is true and there are too many inline back refs, the path
1471  * points to the extent item, and -EAGAIN is returned.
1472  *
1473  * NOTE: inline back refs are ordered in the same way that back ref
1474  *       items in the tree are ordered.
1475  */
1476 static noinline_for_stack
1477 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1478                                  struct btrfs_root *root,
1479                                  struct btrfs_path *path,
1480                                  struct btrfs_extent_inline_ref **ref_ret,
1481                                  u64 bytenr, u64 num_bytes,
1482                                  u64 parent, u64 root_objectid,
1483                                  u64 owner, u64 offset, int insert)
1484 {
1485         struct btrfs_key key;
1486         struct extent_buffer *leaf;
1487         struct btrfs_extent_item *ei;
1488         struct btrfs_extent_inline_ref *iref;
1489         u64 flags;
1490         u64 item_size;
1491         unsigned long ptr;
1492         unsigned long end;
1493         int extra_size;
1494         int type;
1495         int want;
1496         int ret;
1497         int err = 0;
1498         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1499                                                  SKINNY_METADATA);
1500
1501         key.objectid = bytenr;
1502         key.type = BTRFS_EXTENT_ITEM_KEY;
1503         key.offset = num_bytes;
1504
1505         want = extent_ref_type(parent, owner);
1506         if (insert) {
1507                 extra_size = btrfs_extent_inline_ref_size(want);
1508                 path->keep_locks = 1;
1509         } else
1510                 extra_size = -1;
1511
1512         /*
1513          * Owner is our parent level, so we can just add one to get the level
1514          * for the block we are interested in.
1515          */
1516         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1517                 key.type = BTRFS_METADATA_ITEM_KEY;
1518                 key.offset = owner;
1519         }
1520
1521 again:
1522         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1523         if (ret < 0) {
1524                 err = ret;
1525                 goto out;
1526         }
1527
1528         /*
1529          * We may be a newly converted file system which still has the old fat
1530          * extent entries for metadata, so try and see if we have one of those.
1531          */
1532         if (ret > 0 && skinny_metadata) {
1533                 skinny_metadata = false;
1534                 if (path->slots[0]) {
1535                         path->slots[0]--;
1536                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1537                                               path->slots[0]);
1538                         if (key.objectid == bytenr &&
1539                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1540                             key.offset == num_bytes)
1541                                 ret = 0;
1542                 }
1543                 if (ret) {
1544                         key.type = BTRFS_EXTENT_ITEM_KEY;
1545                         key.offset = num_bytes;
1546                         btrfs_release_path(path);
1547                         goto again;
1548                 }
1549         }
1550
1551         if (ret && !insert) {
1552                 err = -ENOENT;
1553                 goto out;
1554         } else if (ret) {
1555                 err = -EIO;
1556                 WARN_ON(1);
1557                 goto out;
1558         }
1559
1560         leaf = path->nodes[0];
1561         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1562 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1563         if (item_size < sizeof(*ei)) {
1564                 if (!insert) {
1565                         err = -ENOENT;
1566                         goto out;
1567                 }
1568                 ret = convert_extent_item_v0(trans, root, path, owner,
1569                                              extra_size);
1570                 if (ret < 0) {
1571                         err = ret;
1572                         goto out;
1573                 }
1574                 leaf = path->nodes[0];
1575                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1576         }
1577 #endif
1578         BUG_ON(item_size < sizeof(*ei));
1579
1580         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1581         flags = btrfs_extent_flags(leaf, ei);
1582
1583         ptr = (unsigned long)(ei + 1);
1584         end = (unsigned long)ei + item_size;
1585
1586         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1587                 ptr += sizeof(struct btrfs_tree_block_info);
1588                 BUG_ON(ptr > end);
1589         }
1590
1591         err = -ENOENT;
1592         while (1) {
1593                 if (ptr >= end) {
1594                         WARN_ON(ptr > end);
1595                         break;
1596                 }
1597                 iref = (struct btrfs_extent_inline_ref *)ptr;
1598                 type = btrfs_extent_inline_ref_type(leaf, iref);
1599                 if (want < type)
1600                         break;
1601                 if (want > type) {
1602                         ptr += btrfs_extent_inline_ref_size(type);
1603                         continue;
1604                 }
1605
1606                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1607                         struct btrfs_extent_data_ref *dref;
1608                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1609                         if (match_extent_data_ref(leaf, dref, root_objectid,
1610                                                   owner, offset)) {
1611                                 err = 0;
1612                                 break;
1613                         }
1614                         if (hash_extent_data_ref_item(leaf, dref) <
1615                             hash_extent_data_ref(root_objectid, owner, offset))
1616                                 break;
1617                 } else {
1618                         u64 ref_offset;
1619                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1620                         if (parent > 0) {
1621                                 if (parent == ref_offset) {
1622                                         err = 0;
1623                                         break;
1624                                 }
1625                                 if (ref_offset < parent)
1626                                         break;
1627                         } else {
1628                                 if (root_objectid == ref_offset) {
1629                                         err = 0;
1630                                         break;
1631                                 }
1632                                 if (ref_offset < root_objectid)
1633                                         break;
1634                         }
1635                 }
1636                 ptr += btrfs_extent_inline_ref_size(type);
1637         }
1638         if (err == -ENOENT && insert) {
1639                 if (item_size + extra_size >=
1640                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1641                         err = -EAGAIN;
1642                         goto out;
1643                 }
1644                 /*
1645                  * To add new inline back ref, we have to make sure
1646                  * there is no corresponding back ref item.
1647                  * For simplicity, we just do not add new inline back
1648                  * ref if there is any kind of item for this block
1649                  */
1650                 if (find_next_key(path, 0, &key) == 0 &&
1651                     key.objectid == bytenr &&
1652                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1653                         err = -EAGAIN;
1654                         goto out;
1655                 }
1656         }
1657         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1658 out:
1659         if (insert) {
1660                 path->keep_locks = 0;
1661                 btrfs_unlock_up_safe(path, 1);
1662         }
1663         return err;
1664 }
1665
1666 /*
1667  * helper to add new inline back ref
1668  */
1669 static noinline_for_stack
1670 void setup_inline_extent_backref(struct btrfs_root *root,
1671                                  struct btrfs_path *path,
1672                                  struct btrfs_extent_inline_ref *iref,
1673                                  u64 parent, u64 root_objectid,
1674                                  u64 owner, u64 offset, int refs_to_add,
1675                                  struct btrfs_delayed_extent_op *extent_op)
1676 {
1677         struct extent_buffer *leaf;
1678         struct btrfs_extent_item *ei;
1679         unsigned long ptr;
1680         unsigned long end;
1681         unsigned long item_offset;
1682         u64 refs;
1683         int size;
1684         int type;
1685
1686         leaf = path->nodes[0];
1687         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1688         item_offset = (unsigned long)iref - (unsigned long)ei;
1689
1690         type = extent_ref_type(parent, owner);
1691         size = btrfs_extent_inline_ref_size(type);
1692
1693         btrfs_extend_item(root, path, size);
1694
1695         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1696         refs = btrfs_extent_refs(leaf, ei);
1697         refs += refs_to_add;
1698         btrfs_set_extent_refs(leaf, ei, refs);
1699         if (extent_op)
1700                 __run_delayed_extent_op(extent_op, leaf, ei);
1701
1702         ptr = (unsigned long)ei + item_offset;
1703         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1704         if (ptr < end - size)
1705                 memmove_extent_buffer(leaf, ptr + size, ptr,
1706                                       end - size - ptr);
1707
1708         iref = (struct btrfs_extent_inline_ref *)ptr;
1709         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1710         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1711                 struct btrfs_extent_data_ref *dref;
1712                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1713                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1714                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1715                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1716                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1717         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1718                 struct btrfs_shared_data_ref *sref;
1719                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1720                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1721                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1722         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1723                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1724         } else {
1725                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1726         }
1727         btrfs_mark_buffer_dirty(leaf);
1728 }
1729
1730 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1731                                  struct btrfs_root *root,
1732                                  struct btrfs_path *path,
1733                                  struct btrfs_extent_inline_ref **ref_ret,
1734                                  u64 bytenr, u64 num_bytes, u64 parent,
1735                                  u64 root_objectid, u64 owner, u64 offset)
1736 {
1737         int ret;
1738
1739         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1740                                            bytenr, num_bytes, parent,
1741                                            root_objectid, owner, offset, 0);
1742         if (ret != -ENOENT)
1743                 return ret;
1744
1745         btrfs_release_path(path);
1746         *ref_ret = NULL;
1747
1748         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1749                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1750                                             root_objectid);
1751         } else {
1752                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1753                                              root_objectid, owner, offset);
1754         }
1755         return ret;
1756 }
1757
1758 /*
1759  * helper to update/remove inline back ref
1760  */
1761 static noinline_for_stack
1762 void update_inline_extent_backref(struct btrfs_root *root,
1763                                   struct btrfs_path *path,
1764                                   struct btrfs_extent_inline_ref *iref,
1765                                   int refs_to_mod,
1766                                   struct btrfs_delayed_extent_op *extent_op)
1767 {
1768         struct extent_buffer *leaf;
1769         struct btrfs_extent_item *ei;
1770         struct btrfs_extent_data_ref *dref = NULL;
1771         struct btrfs_shared_data_ref *sref = NULL;
1772         unsigned long ptr;
1773         unsigned long end;
1774         u32 item_size;
1775         int size;
1776         int type;
1777         u64 refs;
1778
1779         leaf = path->nodes[0];
1780         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1781         refs = btrfs_extent_refs(leaf, ei);
1782         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1783         refs += refs_to_mod;
1784         btrfs_set_extent_refs(leaf, ei, refs);
1785         if (extent_op)
1786                 __run_delayed_extent_op(extent_op, leaf, ei);
1787
1788         type = btrfs_extent_inline_ref_type(leaf, iref);
1789
1790         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1791                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1792                 refs = btrfs_extent_data_ref_count(leaf, dref);
1793         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1794                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1795                 refs = btrfs_shared_data_ref_count(leaf, sref);
1796         } else {
1797                 refs = 1;
1798                 BUG_ON(refs_to_mod != -1);
1799         }
1800
1801         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1802         refs += refs_to_mod;
1803
1804         if (refs > 0) {
1805                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1806                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1807                 else
1808                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1809         } else {
1810                 size =  btrfs_extent_inline_ref_size(type);
1811                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1812                 ptr = (unsigned long)iref;
1813                 end = (unsigned long)ei + item_size;
1814                 if (ptr + size < end)
1815                         memmove_extent_buffer(leaf, ptr, ptr + size,
1816                                               end - ptr - size);
1817                 item_size -= size;
1818                 btrfs_truncate_item(root, path, item_size, 1);
1819         }
1820         btrfs_mark_buffer_dirty(leaf);
1821 }
1822
1823 static noinline_for_stack
1824 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1825                                  struct btrfs_root *root,
1826                                  struct btrfs_path *path,
1827                                  u64 bytenr, u64 num_bytes, u64 parent,
1828                                  u64 root_objectid, u64 owner,
1829                                  u64 offset, int refs_to_add,
1830                                  struct btrfs_delayed_extent_op *extent_op)
1831 {
1832         struct btrfs_extent_inline_ref *iref;
1833         int ret;
1834
1835         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1836                                            bytenr, num_bytes, parent,
1837                                            root_objectid, owner, offset, 1);
1838         if (ret == 0) {
1839                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1840                 update_inline_extent_backref(root, path, iref,
1841                                              refs_to_add, extent_op);
1842         } else if (ret == -ENOENT) {
1843                 setup_inline_extent_backref(root, path, iref, parent,
1844                                             root_objectid, owner, offset,
1845                                             refs_to_add, extent_op);
1846                 ret = 0;
1847         }
1848         return ret;
1849 }
1850
1851 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1852                                  struct btrfs_root *root,
1853                                  struct btrfs_path *path,
1854                                  u64 bytenr, u64 parent, u64 root_objectid,
1855                                  u64 owner, u64 offset, int refs_to_add)
1856 {
1857         int ret;
1858         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1859                 BUG_ON(refs_to_add != 1);
1860                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1861                                             parent, root_objectid);
1862         } else {
1863                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1864                                              parent, root_objectid,
1865                                              owner, offset, refs_to_add);
1866         }
1867         return ret;
1868 }
1869
1870 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1871                                  struct btrfs_root *root,
1872                                  struct btrfs_path *path,
1873                                  struct btrfs_extent_inline_ref *iref,
1874                                  int refs_to_drop, int is_data)
1875 {
1876         int ret = 0;
1877
1878         BUG_ON(!is_data && refs_to_drop != 1);
1879         if (iref) {
1880                 update_inline_extent_backref(root, path, iref,
1881                                              -refs_to_drop, NULL);
1882         } else if (is_data) {
1883                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1884         } else {
1885                 ret = btrfs_del_item(trans, root, path);
1886         }
1887         return ret;
1888 }
1889
1890 static int btrfs_issue_discard(struct block_device *bdev,
1891                                 u64 start, u64 len)
1892 {
1893         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1894 }
1895
1896 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1897                                 u64 num_bytes, u64 *actual_bytes)
1898 {
1899         int ret;
1900         u64 discarded_bytes = 0;
1901         struct btrfs_bio *bbio = NULL;
1902
1903
1904         /* Tell the block device(s) that the sectors can be discarded */
1905         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1906                               bytenr, &num_bytes, &bbio, 0);
1907         /* Error condition is -ENOMEM */
1908         if (!ret) {
1909                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1910                 int i;
1911
1912
1913                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1914                         if (!stripe->dev->can_discard)
1915                                 continue;
1916
1917                         ret = btrfs_issue_discard(stripe->dev->bdev,
1918                                                   stripe->physical,
1919                                                   stripe->length);
1920                         if (!ret)
1921                                 discarded_bytes += stripe->length;
1922                         else if (ret != -EOPNOTSUPP)
1923                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1924
1925                         /*
1926                          * Just in case we get back EOPNOTSUPP for some reason,
1927                          * just ignore the return value so we don't screw up
1928                          * people calling discard_extent.
1929                          */
1930                         ret = 0;
1931                 }
1932                 kfree(bbio);
1933         }
1934
1935         if (actual_bytes)
1936                 *actual_bytes = discarded_bytes;
1937
1938
1939         if (ret == -EOPNOTSUPP)
1940                 ret = 0;
1941         return ret;
1942 }
1943
1944 /* Can return -ENOMEM */
1945 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1946                          struct btrfs_root *root,
1947                          u64 bytenr, u64 num_bytes, u64 parent,
1948                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1949 {
1950         int ret;
1951         struct btrfs_fs_info *fs_info = root->fs_info;
1952
1953         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1954                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1955
1956         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1957                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1958                                         num_bytes,
1959                                         parent, root_objectid, (int)owner,
1960                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1961         } else {
1962                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1963                                         num_bytes,
1964                                         parent, root_objectid, owner, offset,
1965                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1966         }
1967         return ret;
1968 }
1969
1970 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1971                                   struct btrfs_root *root,
1972                                   u64 bytenr, u64 num_bytes,
1973                                   u64 parent, u64 root_objectid,
1974                                   u64 owner, u64 offset, int refs_to_add,
1975                                   struct btrfs_delayed_extent_op *extent_op)
1976 {
1977         struct btrfs_path *path;
1978         struct extent_buffer *leaf;
1979         struct btrfs_extent_item *item;
1980         u64 refs;
1981         int ret;
1982         int err = 0;
1983
1984         path = btrfs_alloc_path();
1985         if (!path)
1986                 return -ENOMEM;
1987
1988         path->reada = 1;
1989         path->leave_spinning = 1;
1990         /* this will setup the path even if it fails to insert the back ref */
1991         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1992                                            path, bytenr, num_bytes, parent,
1993                                            root_objectid, owner, offset,
1994                                            refs_to_add, extent_op);
1995         if (ret == 0)
1996                 goto out;
1997
1998         if (ret != -EAGAIN) {
1999                 err = ret;
2000                 goto out;
2001         }
2002
2003         leaf = path->nodes[0];
2004         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2005         refs = btrfs_extent_refs(leaf, item);
2006         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2007         if (extent_op)
2008                 __run_delayed_extent_op(extent_op, leaf, item);
2009
2010         btrfs_mark_buffer_dirty(leaf);
2011         btrfs_release_path(path);
2012
2013         path->reada = 1;
2014         path->leave_spinning = 1;
2015
2016         /* now insert the actual backref */
2017         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2018                                     path, bytenr, parent, root_objectid,
2019                                     owner, offset, refs_to_add);
2020         if (ret)
2021                 btrfs_abort_transaction(trans, root, ret);
2022 out:
2023         btrfs_free_path(path);
2024         return err;
2025 }
2026
2027 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2028                                 struct btrfs_root *root,
2029                                 struct btrfs_delayed_ref_node *node,
2030                                 struct btrfs_delayed_extent_op *extent_op,
2031                                 int insert_reserved)
2032 {
2033         int ret = 0;
2034         struct btrfs_delayed_data_ref *ref;
2035         struct btrfs_key ins;
2036         u64 parent = 0;
2037         u64 ref_root = 0;
2038         u64 flags = 0;
2039
2040         ins.objectid = node->bytenr;
2041         ins.offset = node->num_bytes;
2042         ins.type = BTRFS_EXTENT_ITEM_KEY;
2043
2044         ref = btrfs_delayed_node_to_data_ref(node);
2045         trace_run_delayed_data_ref(node, ref, node->action);
2046
2047         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2048                 parent = ref->parent;
2049         else
2050                 ref_root = ref->root;
2051
2052         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2053                 if (extent_op)
2054                         flags |= extent_op->flags_to_set;
2055                 ret = alloc_reserved_file_extent(trans, root,
2056                                                  parent, ref_root, flags,
2057                                                  ref->objectid, ref->offset,
2058                                                  &ins, node->ref_mod);
2059         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2060                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2061                                              node->num_bytes, parent,
2062                                              ref_root, ref->objectid,
2063                                              ref->offset, node->ref_mod,
2064                                              extent_op);
2065         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2066                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2067                                           node->num_bytes, parent,
2068                                           ref_root, ref->objectid,
2069                                           ref->offset, node->ref_mod,
2070                                           extent_op);
2071         } else {
2072                 BUG();
2073         }
2074         return ret;
2075 }
2076
2077 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2078                                     struct extent_buffer *leaf,
2079                                     struct btrfs_extent_item *ei)
2080 {
2081         u64 flags = btrfs_extent_flags(leaf, ei);
2082         if (extent_op->update_flags) {
2083                 flags |= extent_op->flags_to_set;
2084                 btrfs_set_extent_flags(leaf, ei, flags);
2085         }
2086
2087         if (extent_op->update_key) {
2088                 struct btrfs_tree_block_info *bi;
2089                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2090                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2091                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2092         }
2093 }
2094
2095 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2096                                  struct btrfs_root *root,
2097                                  struct btrfs_delayed_ref_node *node,
2098                                  struct btrfs_delayed_extent_op *extent_op)
2099 {
2100         struct btrfs_key key;
2101         struct btrfs_path *path;
2102         struct btrfs_extent_item *ei;
2103         struct extent_buffer *leaf;
2104         u32 item_size;
2105         int ret;
2106         int err = 0;
2107         int metadata = !extent_op->is_data;
2108
2109         if (trans->aborted)
2110                 return 0;
2111
2112         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2113                 metadata = 0;
2114
2115         path = btrfs_alloc_path();
2116         if (!path)
2117                 return -ENOMEM;
2118
2119         key.objectid = node->bytenr;
2120
2121         if (metadata) {
2122                 key.type = BTRFS_METADATA_ITEM_KEY;
2123                 key.offset = extent_op->level;
2124         } else {
2125                 key.type = BTRFS_EXTENT_ITEM_KEY;
2126                 key.offset = node->num_bytes;
2127         }
2128
2129 again:
2130         path->reada = 1;
2131         path->leave_spinning = 1;
2132         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2133                                 path, 0, 1);
2134         if (ret < 0) {
2135                 err = ret;
2136                 goto out;
2137         }
2138         if (ret > 0) {
2139                 if (metadata) {
2140                         btrfs_release_path(path);
2141                         metadata = 0;
2142
2143                         key.offset = node->num_bytes;
2144                         key.type = BTRFS_EXTENT_ITEM_KEY;
2145                         goto again;
2146                 }
2147                 err = -EIO;
2148                 goto out;
2149         }
2150
2151         leaf = path->nodes[0];
2152         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2153 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2154         if (item_size < sizeof(*ei)) {
2155                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2156                                              path, (u64)-1, 0);
2157                 if (ret < 0) {
2158                         err = ret;
2159                         goto out;
2160                 }
2161                 leaf = path->nodes[0];
2162                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2163         }
2164 #endif
2165         BUG_ON(item_size < sizeof(*ei));
2166         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2167         __run_delayed_extent_op(extent_op, leaf, ei);
2168
2169         btrfs_mark_buffer_dirty(leaf);
2170 out:
2171         btrfs_free_path(path);
2172         return err;
2173 }
2174
2175 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2176                                 struct btrfs_root *root,
2177                                 struct btrfs_delayed_ref_node *node,
2178                                 struct btrfs_delayed_extent_op *extent_op,
2179                                 int insert_reserved)
2180 {
2181         int ret = 0;
2182         struct btrfs_delayed_tree_ref *ref;
2183         struct btrfs_key ins;
2184         u64 parent = 0;
2185         u64 ref_root = 0;
2186         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2187                                                  SKINNY_METADATA);
2188
2189         ref = btrfs_delayed_node_to_tree_ref(node);
2190         trace_run_delayed_tree_ref(node, ref, node->action);
2191
2192         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2193                 parent = ref->parent;
2194         else
2195                 ref_root = ref->root;
2196
2197         ins.objectid = node->bytenr;
2198         if (skinny_metadata) {
2199                 ins.offset = ref->level;
2200                 ins.type = BTRFS_METADATA_ITEM_KEY;
2201         } else {
2202                 ins.offset = node->num_bytes;
2203                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2204         }
2205
2206         BUG_ON(node->ref_mod != 1);
2207         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2208                 BUG_ON(!extent_op || !extent_op->update_flags);
2209                 ret = alloc_reserved_tree_block(trans, root,
2210                                                 parent, ref_root,
2211                                                 extent_op->flags_to_set,
2212                                                 &extent_op->key,
2213                                                 ref->level, &ins);
2214         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2215                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2216                                              node->num_bytes, parent, ref_root,
2217                                              ref->level, 0, 1, extent_op);
2218         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2219                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2220                                           node->num_bytes, parent, ref_root,
2221                                           ref->level, 0, 1, extent_op);
2222         } else {
2223                 BUG();
2224         }
2225         return ret;
2226 }
2227
2228 /* helper function to actually process a single delayed ref entry */
2229 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2230                                struct btrfs_root *root,
2231                                struct btrfs_delayed_ref_node *node,
2232                                struct btrfs_delayed_extent_op *extent_op,
2233                                int insert_reserved)
2234 {
2235         int ret = 0;
2236
2237         if (trans->aborted) {
2238                 if (insert_reserved)
2239                         btrfs_pin_extent(root, node->bytenr,
2240                                          node->num_bytes, 1);
2241                 return 0;
2242         }
2243
2244         if (btrfs_delayed_ref_is_head(node)) {
2245                 struct btrfs_delayed_ref_head *head;
2246                 /*
2247                  * we've hit the end of the chain and we were supposed
2248                  * to insert this extent into the tree.  But, it got
2249                  * deleted before we ever needed to insert it, so all
2250                  * we have to do is clean up the accounting
2251                  */
2252                 BUG_ON(extent_op);
2253                 head = btrfs_delayed_node_to_head(node);
2254                 trace_run_delayed_ref_head(node, head, node->action);
2255
2256                 if (insert_reserved) {
2257                         btrfs_pin_extent(root, node->bytenr,
2258                                          node->num_bytes, 1);
2259                         if (head->is_data) {
2260                                 ret = btrfs_del_csums(trans, root,
2261                                                       node->bytenr,
2262                                                       node->num_bytes);
2263                         }
2264                 }
2265                 return ret;
2266         }
2267
2268         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2269             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2270                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2271                                            insert_reserved);
2272         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2273                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2274                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2275                                            insert_reserved);
2276         else
2277                 BUG();
2278         return ret;
2279 }
2280
2281 static noinline struct btrfs_delayed_ref_node *
2282 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2283 {
2284         struct rb_node *node;
2285         struct btrfs_delayed_ref_node *ref;
2286         int action = BTRFS_ADD_DELAYED_REF;
2287 again:
2288         /*
2289          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2290          * this prevents ref count from going down to zero when
2291          * there still are pending delayed ref.
2292          */
2293         node = rb_prev(&head->node.rb_node);
2294         while (1) {
2295                 if (!node)
2296                         break;
2297                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2298                                 rb_node);
2299                 if (ref->bytenr != head->node.bytenr)
2300                         break;
2301                 if (ref->action == action)
2302                         return ref;
2303                 node = rb_prev(node);
2304         }
2305         if (action == BTRFS_ADD_DELAYED_REF) {
2306                 action = BTRFS_DROP_DELAYED_REF;
2307                 goto again;
2308         }
2309         return NULL;
2310 }
2311
2312 /*
2313  * Returns 0 on success or if called with an already aborted transaction.
2314  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2315  */
2316 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2317                                        struct btrfs_root *root,
2318                                        struct list_head *cluster)
2319 {
2320         struct btrfs_delayed_ref_root *delayed_refs;
2321         struct btrfs_delayed_ref_node *ref;
2322         struct btrfs_delayed_ref_head *locked_ref = NULL;
2323         struct btrfs_delayed_extent_op *extent_op;
2324         struct btrfs_fs_info *fs_info = root->fs_info;
2325         int ret;
2326         int count = 0;
2327         int must_insert_reserved = 0;
2328
2329         delayed_refs = &trans->transaction->delayed_refs;
2330         while (1) {
2331                 if (!locked_ref) {
2332                         /* pick a new head ref from the cluster list */
2333                         if (list_empty(cluster))
2334                                 break;
2335
2336                         locked_ref = list_entry(cluster->next,
2337                                      struct btrfs_delayed_ref_head, cluster);
2338
2339                         /* grab the lock that says we are going to process
2340                          * all the refs for this head */
2341                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2342
2343                         /*
2344                          * we may have dropped the spin lock to get the head
2345                          * mutex lock, and that might have given someone else
2346                          * time to free the head.  If that's true, it has been
2347                          * removed from our list and we can move on.
2348                          */
2349                         if (ret == -EAGAIN) {
2350                                 locked_ref = NULL;
2351                                 count++;
2352                                 continue;
2353                         }
2354                 }
2355
2356                 /*
2357                  * We need to try and merge add/drops of the same ref since we
2358                  * can run into issues with relocate dropping the implicit ref
2359                  * and then it being added back again before the drop can
2360                  * finish.  If we merged anything we need to re-loop so we can
2361                  * get a good ref.
2362                  */
2363                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2364                                          locked_ref);
2365
2366                 /*
2367                  * locked_ref is the head node, so we have to go one
2368                  * node back for any delayed ref updates
2369                  */
2370                 ref = select_delayed_ref(locked_ref);
2371
2372                 if (ref && ref->seq &&
2373                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2374                         /*
2375                          * there are still refs with lower seq numbers in the
2376                          * process of being added. Don't run this ref yet.
2377                          */
2378                         list_del_init(&locked_ref->cluster);
2379                         btrfs_delayed_ref_unlock(locked_ref);
2380                         locked_ref = NULL;
2381                         delayed_refs->num_heads_ready++;
2382                         spin_unlock(&delayed_refs->lock);
2383                         cond_resched();
2384                         spin_lock(&delayed_refs->lock);
2385                         continue;
2386                 }
2387
2388                 /*
2389                  * record the must insert reserved flag before we
2390                  * drop the spin lock.
2391                  */
2392                 must_insert_reserved = locked_ref->must_insert_reserved;
2393                 locked_ref->must_insert_reserved = 0;
2394
2395                 extent_op = locked_ref->extent_op;
2396                 locked_ref->extent_op = NULL;
2397
2398                 if (!ref) {
2399                         /* All delayed refs have been processed, Go ahead
2400                          * and send the head node to run_one_delayed_ref,
2401                          * so that any accounting fixes can happen
2402                          */
2403                         ref = &locked_ref->node;
2404
2405                         if (extent_op && must_insert_reserved) {
2406                                 btrfs_free_delayed_extent_op(extent_op);
2407                                 extent_op = NULL;
2408                         }
2409
2410                         if (extent_op) {
2411                                 spin_unlock(&delayed_refs->lock);
2412
2413                                 ret = run_delayed_extent_op(trans, root,
2414                                                             ref, extent_op);
2415                                 btrfs_free_delayed_extent_op(extent_op);
2416
2417                                 if (ret) {
2418                                         /*
2419                                          * Need to reset must_insert_reserved if
2420                                          * there was an error so the abort stuff
2421                                          * can cleanup the reserved space
2422                                          * properly.
2423                                          */
2424                                         if (must_insert_reserved)
2425                                                 locked_ref->must_insert_reserved = 1;
2426                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2427                                         spin_lock(&delayed_refs->lock);
2428                                         btrfs_delayed_ref_unlock(locked_ref);
2429                                         return ret;
2430                                 }
2431
2432                                 goto next;
2433                         }
2434                 }
2435
2436                 ref->in_tree = 0;
2437                 rb_erase(&ref->rb_node, &delayed_refs->root);
2438                 delayed_refs->num_entries--;
2439                 if (!btrfs_delayed_ref_is_head(ref)) {
2440                         /*
2441                          * when we play the delayed ref, also correct the
2442                          * ref_mod on head
2443                          */
2444                         switch (ref->action) {
2445                         case BTRFS_ADD_DELAYED_REF:
2446                         case BTRFS_ADD_DELAYED_EXTENT:
2447                                 locked_ref->node.ref_mod -= ref->ref_mod;
2448                                 break;
2449                         case BTRFS_DROP_DELAYED_REF:
2450                                 locked_ref->node.ref_mod += ref->ref_mod;
2451                                 break;
2452                         default:
2453                                 WARN_ON(1);
2454                         }
2455                 } else {
2456                         list_del_init(&locked_ref->cluster);
2457                 }
2458                 spin_unlock(&delayed_refs->lock);
2459
2460                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2461                                           must_insert_reserved);
2462
2463                 btrfs_free_delayed_extent_op(extent_op);
2464                 if (ret) {
2465                         btrfs_delayed_ref_unlock(locked_ref);
2466                         btrfs_put_delayed_ref(ref);
2467                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2468                         spin_lock(&delayed_refs->lock);
2469                         return ret;
2470                 }
2471
2472                 /*
2473                  * If this node is a head, that means all the refs in this head
2474                  * have been dealt with, and we will pick the next head to deal
2475                  * with, so we must unlock the head and drop it from the cluster
2476                  * list before we release it.
2477                  */
2478                 if (btrfs_delayed_ref_is_head(ref)) {
2479                         btrfs_delayed_ref_unlock(locked_ref);
2480                         locked_ref = NULL;
2481                 }
2482                 btrfs_put_delayed_ref(ref);
2483                 count++;
2484 next:
2485                 cond_resched();
2486                 spin_lock(&delayed_refs->lock);
2487         }
2488         return count;
2489 }
2490
2491 #ifdef SCRAMBLE_DELAYED_REFS
2492 /*
2493  * Normally delayed refs get processed in ascending bytenr order. This
2494  * correlates in most cases to the order added. To expose dependencies on this
2495  * order, we start to process the tree in the middle instead of the beginning
2496  */
2497 static u64 find_middle(struct rb_root *root)
2498 {
2499         struct rb_node *n = root->rb_node;
2500         struct btrfs_delayed_ref_node *entry;
2501         int alt = 1;
2502         u64 middle;
2503         u64 first = 0, last = 0;
2504
2505         n = rb_first(root);
2506         if (n) {
2507                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2508                 first = entry->bytenr;
2509         }
2510         n = rb_last(root);
2511         if (n) {
2512                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2513                 last = entry->bytenr;
2514         }
2515         n = root->rb_node;
2516
2517         while (n) {
2518                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2519                 WARN_ON(!entry->in_tree);
2520
2521                 middle = entry->bytenr;
2522
2523                 if (alt)
2524                         n = n->rb_left;
2525                 else
2526                         n = n->rb_right;
2527
2528                 alt = 1 - alt;
2529         }
2530         return middle;
2531 }
2532 #endif
2533
2534 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2535                                          struct btrfs_fs_info *fs_info)
2536 {
2537         struct qgroup_update *qgroup_update;
2538         int ret = 0;
2539
2540         if (list_empty(&trans->qgroup_ref_list) !=
2541             !trans->delayed_ref_elem.seq) {
2542                 /* list without seq or seq without list */
2543                 btrfs_err(fs_info,
2544                         "qgroup accounting update error, list is%s empty, seq is %#x.%x",
2545                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2546                         (u32)(trans->delayed_ref_elem.seq >> 32),
2547                         (u32)trans->delayed_ref_elem.seq);
2548                 BUG();
2549         }
2550
2551         if (!trans->delayed_ref_elem.seq)
2552                 return 0;
2553
2554         while (!list_empty(&trans->qgroup_ref_list)) {
2555                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2556                                                  struct qgroup_update, list);
2557                 list_del(&qgroup_update->list);
2558                 if (!ret)
2559                         ret = btrfs_qgroup_account_ref(
2560                                         trans, fs_info, qgroup_update->node,
2561                                         qgroup_update->extent_op);
2562                 kfree(qgroup_update);
2563         }
2564
2565         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2566
2567         return ret;
2568 }
2569
2570 static int refs_newer(struct btrfs_delayed_ref_root *delayed_refs, int seq,
2571                       int count)
2572 {
2573         int val = atomic_read(&delayed_refs->ref_seq);
2574
2575         if (val < seq || val >= seq + count)
2576                 return 1;
2577         return 0;
2578 }
2579
2580 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2581 {
2582         u64 num_bytes;
2583
2584         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2585                              sizeof(struct btrfs_extent_inline_ref));
2586         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2587                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2588
2589         /*
2590          * We don't ever fill up leaves all the way so multiply by 2 just to be
2591          * closer to what we're really going to want to ouse.
2592          */
2593         return div64_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2594 }
2595
2596 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2597                                        struct btrfs_root *root)
2598 {
2599         struct btrfs_block_rsv *global_rsv;
2600         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2601         u64 num_bytes;
2602         int ret = 0;
2603
2604         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2605         num_heads = heads_to_leaves(root, num_heads);
2606         if (num_heads > 1)
2607                 num_bytes += (num_heads - 1) * root->leafsize;
2608         num_bytes <<= 1;
2609         global_rsv = &root->fs_info->global_block_rsv;
2610
2611         /*
2612          * If we can't allocate any more chunks lets make sure we have _lots_ of
2613          * wiggle room since running delayed refs can create more delayed refs.
2614          */
2615         if (global_rsv->space_info->full)
2616                 num_bytes <<= 1;
2617
2618         spin_lock(&global_rsv->lock);
2619         if (global_rsv->reserved <= num_bytes)
2620                 ret = 1;
2621         spin_unlock(&global_rsv->lock);
2622         return ret;
2623 }
2624
2625 /*
2626  * this starts processing the delayed reference count updates and
2627  * extent insertions we have queued up so far.  count can be
2628  * 0, which means to process everything in the tree at the start
2629  * of the run (but not newly added entries), or it can be some target
2630  * number you'd like to process.
2631  *
2632  * Returns 0 on success or if called with an aborted transaction
2633  * Returns <0 on error and aborts the transaction
2634  */
2635 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2636                            struct btrfs_root *root, unsigned long count)
2637 {
2638         struct rb_node *node;
2639         struct btrfs_delayed_ref_root *delayed_refs;
2640         struct btrfs_delayed_ref_node *ref;
2641         struct list_head cluster;
2642         int ret;
2643         u64 delayed_start;
2644         int run_all = count == (unsigned long)-1;
2645         int run_most = 0;
2646         int loops;
2647
2648         /* We'll clean this up in btrfs_cleanup_transaction */
2649         if (trans->aborted)
2650                 return 0;
2651
2652         if (root == root->fs_info->extent_root)
2653                 root = root->fs_info->tree_root;
2654
2655         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2656
2657         delayed_refs = &trans->transaction->delayed_refs;
2658         INIT_LIST_HEAD(&cluster);
2659         if (count == 0) {
2660                 count = delayed_refs->num_entries * 2;
2661                 run_most = 1;
2662         }
2663
2664         if (!run_all && !run_most) {
2665                 int old;
2666                 int seq = atomic_read(&delayed_refs->ref_seq);
2667
2668 progress:
2669                 old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2670                 if (old) {
2671                         DEFINE_WAIT(__wait);
2672                         if (delayed_refs->flushing ||
2673                             !btrfs_should_throttle_delayed_refs(trans, root))
2674                                 return 0;
2675
2676                         prepare_to_wait(&delayed_refs->wait, &__wait,
2677                                         TASK_UNINTERRUPTIBLE);
2678
2679                         old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2680                         if (old) {
2681                                 schedule();
2682                                 finish_wait(&delayed_refs->wait, &__wait);
2683
2684                                 if (!refs_newer(delayed_refs, seq, 256))
2685                                         goto progress;
2686                                 else
2687                                         return 0;
2688                         } else {
2689                                 finish_wait(&delayed_refs->wait, &__wait);
2690                                 goto again;
2691                         }
2692                 }
2693
2694         } else {
2695                 atomic_inc(&delayed_refs->procs_running_refs);
2696         }
2697
2698 again:
2699         loops = 0;
2700         spin_lock(&delayed_refs->lock);
2701
2702 #ifdef SCRAMBLE_DELAYED_REFS
2703         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2704 #endif
2705
2706         while (1) {
2707                 if (!(run_all || run_most) &&
2708                     !btrfs_should_throttle_delayed_refs(trans, root))
2709                         break;
2710
2711                 /*
2712                  * go find something we can process in the rbtree.  We start at
2713                  * the beginning of the tree, and then build a cluster
2714                  * of refs to process starting at the first one we are able to
2715                  * lock
2716                  */
2717                 delayed_start = delayed_refs->run_delayed_start;
2718                 ret = btrfs_find_ref_cluster(trans, &cluster,
2719                                              delayed_refs->run_delayed_start);
2720                 if (ret)
2721                         break;
2722
2723                 ret = run_clustered_refs(trans, root, &cluster);
2724                 if (ret < 0) {
2725                         btrfs_release_ref_cluster(&cluster);
2726                         spin_unlock(&delayed_refs->lock);
2727                         btrfs_abort_transaction(trans, root, ret);
2728                         atomic_dec(&delayed_refs->procs_running_refs);
2729                         wake_up(&delayed_refs->wait);
2730                         return ret;
2731                 }
2732
2733                 atomic_add(ret, &delayed_refs->ref_seq);
2734
2735                 count -= min_t(unsigned long, ret, count);
2736
2737                 if (count == 0)
2738                         break;
2739
2740                 if (delayed_start >= delayed_refs->run_delayed_start) {
2741                         if (loops == 0) {
2742                                 /*
2743                                  * btrfs_find_ref_cluster looped. let's do one
2744                                  * more cycle. if we don't run any delayed ref
2745                                  * during that cycle (because we can't because
2746                                  * all of them are blocked), bail out.
2747                                  */
2748                                 loops = 1;
2749                         } else {
2750                                 /*
2751                                  * no runnable refs left, stop trying
2752                                  */
2753                                 BUG_ON(run_all);
2754                                 break;
2755                         }
2756                 }
2757                 if (ret) {
2758                         /* refs were run, let's reset staleness detection */
2759                         loops = 0;
2760                 }
2761         }
2762
2763         if (run_all) {
2764                 if (!list_empty(&trans->new_bgs)) {
2765                         spin_unlock(&delayed_refs->lock);
2766                         btrfs_create_pending_block_groups(trans, root);
2767                         spin_lock(&delayed_refs->lock);
2768                 }
2769
2770                 node = rb_first(&delayed_refs->root);
2771                 if (!node)
2772                         goto out;
2773                 count = (unsigned long)-1;
2774
2775                 while (node) {
2776                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2777                                        rb_node);
2778                         if (btrfs_delayed_ref_is_head(ref)) {
2779                                 struct btrfs_delayed_ref_head *head;
2780
2781                                 head = btrfs_delayed_node_to_head(ref);
2782                                 atomic_inc(&ref->refs);
2783
2784                                 spin_unlock(&delayed_refs->lock);
2785                                 /*
2786                                  * Mutex was contended, block until it's
2787                                  * released and try again
2788                                  */
2789                                 mutex_lock(&head->mutex);
2790                                 mutex_unlock(&head->mutex);
2791
2792                                 btrfs_put_delayed_ref(ref);
2793                                 cond_resched();
2794                                 goto again;
2795                         }
2796                         node = rb_next(node);
2797                 }
2798                 spin_unlock(&delayed_refs->lock);
2799                 schedule_timeout(1);
2800                 goto again;
2801         }
2802 out:
2803         atomic_dec(&delayed_refs->procs_running_refs);
2804         smp_mb();
2805         if (waitqueue_active(&delayed_refs->wait))
2806                 wake_up(&delayed_refs->wait);
2807
2808         spin_unlock(&delayed_refs->lock);
2809         assert_qgroups_uptodate(trans);
2810         return 0;
2811 }
2812
2813 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2814                                 struct btrfs_root *root,
2815                                 u64 bytenr, u64 num_bytes, u64 flags,
2816                                 int level, int is_data)
2817 {
2818         struct btrfs_delayed_extent_op *extent_op;
2819         int ret;
2820
2821         extent_op = btrfs_alloc_delayed_extent_op();
2822         if (!extent_op)
2823                 return -ENOMEM;
2824
2825         extent_op->flags_to_set = flags;
2826         extent_op->update_flags = 1;
2827         extent_op->update_key = 0;
2828         extent_op->is_data = is_data ? 1 : 0;
2829         extent_op->level = level;
2830
2831         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2832                                           num_bytes, extent_op);
2833         if (ret)
2834                 btrfs_free_delayed_extent_op(extent_op);
2835         return ret;
2836 }
2837
2838 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2839                                       struct btrfs_root *root,
2840                                       struct btrfs_path *path,
2841                                       u64 objectid, u64 offset, u64 bytenr)
2842 {
2843         struct btrfs_delayed_ref_head *head;
2844         struct btrfs_delayed_ref_node *ref;
2845         struct btrfs_delayed_data_ref *data_ref;
2846         struct btrfs_delayed_ref_root *delayed_refs;
2847         struct rb_node *node;
2848         int ret = 0;
2849
2850         ret = -ENOENT;
2851         delayed_refs = &trans->transaction->delayed_refs;
2852         spin_lock(&delayed_refs->lock);
2853         head = btrfs_find_delayed_ref_head(trans, bytenr);
2854         if (!head)
2855                 goto out;
2856
2857         if (!mutex_trylock(&head->mutex)) {
2858                 atomic_inc(&head->node.refs);
2859                 spin_unlock(&delayed_refs->lock);
2860
2861                 btrfs_release_path(path);
2862
2863                 /*
2864                  * Mutex was contended, block until it's released and let
2865                  * caller try again
2866                  */
2867                 mutex_lock(&head->mutex);
2868                 mutex_unlock(&head->mutex);
2869                 btrfs_put_delayed_ref(&head->node);
2870                 return -EAGAIN;
2871         }
2872
2873         node = rb_prev(&head->node.rb_node);
2874         if (!node)
2875                 goto out_unlock;
2876
2877         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2878
2879         if (ref->bytenr != bytenr)
2880                 goto out_unlock;
2881
2882         ret = 1;
2883         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2884                 goto out_unlock;
2885
2886         data_ref = btrfs_delayed_node_to_data_ref(ref);
2887
2888         node = rb_prev(node);
2889         if (node) {
2890                 int seq = ref->seq;
2891
2892                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2893                 if (ref->bytenr == bytenr && ref->seq == seq)
2894                         goto out_unlock;
2895         }
2896
2897         if (data_ref->root != root->root_key.objectid ||
2898             data_ref->objectid != objectid || data_ref->offset != offset)
2899                 goto out_unlock;
2900
2901         ret = 0;
2902 out_unlock:
2903         mutex_unlock(&head->mutex);
2904 out:
2905         spin_unlock(&delayed_refs->lock);
2906         return ret;
2907 }
2908
2909 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2910                                         struct btrfs_root *root,
2911                                         struct btrfs_path *path,
2912                                         u64 objectid, u64 offset, u64 bytenr)
2913 {
2914         struct btrfs_root *extent_root = root->fs_info->extent_root;
2915         struct extent_buffer *leaf;
2916         struct btrfs_extent_data_ref *ref;
2917         struct btrfs_extent_inline_ref *iref;
2918         struct btrfs_extent_item *ei;
2919         struct btrfs_key key;
2920         u32 item_size;
2921         int ret;
2922
2923         key.objectid = bytenr;
2924         key.offset = (u64)-1;
2925         key.type = BTRFS_EXTENT_ITEM_KEY;
2926
2927         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2928         if (ret < 0)
2929                 goto out;
2930         BUG_ON(ret == 0); /* Corruption */
2931
2932         ret = -ENOENT;
2933         if (path->slots[0] == 0)
2934                 goto out;
2935
2936         path->slots[0]--;
2937         leaf = path->nodes[0];
2938         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2939
2940         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2941                 goto out;
2942
2943         ret = 1;
2944         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2945 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2946         if (item_size < sizeof(*ei)) {
2947                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2948                 goto out;
2949         }
2950 #endif
2951         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2952
2953         if (item_size != sizeof(*ei) +
2954             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2955                 goto out;
2956
2957         if (btrfs_extent_generation(leaf, ei) <=
2958             btrfs_root_last_snapshot(&root->root_item))
2959                 goto out;
2960
2961         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2962         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2963             BTRFS_EXTENT_DATA_REF_KEY)
2964                 goto out;
2965
2966         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2967         if (btrfs_extent_refs(leaf, ei) !=
2968             btrfs_extent_data_ref_count(leaf, ref) ||
2969             btrfs_extent_data_ref_root(leaf, ref) !=
2970             root->root_key.objectid ||
2971             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2972             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2973                 goto out;
2974
2975         ret = 0;
2976 out:
2977         return ret;
2978 }
2979
2980 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2981                           struct btrfs_root *root,
2982                           u64 objectid, u64 offset, u64 bytenr)
2983 {
2984         struct btrfs_path *path;
2985         int ret;
2986         int ret2;
2987
2988         path = btrfs_alloc_path();
2989         if (!path)
2990                 return -ENOENT;
2991
2992         do {
2993                 ret = check_committed_ref(trans, root, path, objectid,
2994                                           offset, bytenr);
2995                 if (ret && ret != -ENOENT)
2996                         goto out;
2997
2998                 ret2 = check_delayed_ref(trans, root, path, objectid,
2999                                          offset, bytenr);
3000         } while (ret2 == -EAGAIN);
3001
3002         if (ret2 && ret2 != -ENOENT) {
3003                 ret = ret2;
3004                 goto out;
3005         }
3006
3007         if (ret != -ENOENT || ret2 != -ENOENT)
3008                 ret = 0;
3009 out:
3010         btrfs_free_path(path);
3011         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3012                 WARN_ON(ret > 0);
3013         return ret;
3014 }
3015
3016 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3017                            struct btrfs_root *root,
3018                            struct extent_buffer *buf,
3019                            int full_backref, int inc, int for_cow)
3020 {
3021         u64 bytenr;
3022         u64 num_bytes;
3023         u64 parent;
3024         u64 ref_root;
3025         u32 nritems;
3026         struct btrfs_key key;
3027         struct btrfs_file_extent_item *fi;
3028         int i;
3029         int level;
3030         int ret = 0;
3031         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3032                             u64, u64, u64, u64, u64, u64, int);
3033
3034         ref_root = btrfs_header_owner(buf);
3035         nritems = btrfs_header_nritems(buf);
3036         level = btrfs_header_level(buf);
3037
3038         if (!root->ref_cows && level == 0)
3039                 return 0;
3040
3041         if (inc)
3042                 process_func = btrfs_inc_extent_ref;
3043         else
3044                 process_func = btrfs_free_extent;
3045
3046         if (full_backref)
3047                 parent = buf->start;
3048         else
3049                 parent = 0;
3050
3051         for (i = 0; i < nritems; i++) {
3052                 if (level == 0) {
3053                         btrfs_item_key_to_cpu(buf, &key, i);
3054                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3055                                 continue;
3056                         fi = btrfs_item_ptr(buf, i,
3057                                             struct btrfs_file_extent_item);
3058                         if (btrfs_file_extent_type(buf, fi) ==
3059                             BTRFS_FILE_EXTENT_INLINE)
3060                                 continue;
3061                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3062                         if (bytenr == 0)
3063                                 continue;
3064
3065                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3066                         key.offset -= btrfs_file_extent_offset(buf, fi);
3067                         ret = process_func(trans, root, bytenr, num_bytes,
3068                                            parent, ref_root, key.objectid,
3069                                            key.offset, for_cow);
3070                         if (ret)
3071                                 goto fail;
3072                 } else {
3073                         bytenr = btrfs_node_blockptr(buf, i);
3074                         num_bytes = btrfs_level_size(root, level - 1);
3075                         ret = process_func(trans, root, bytenr, num_bytes,
3076                                            parent, ref_root, level - 1, 0,
3077                                            for_cow);
3078                         if (ret)
3079                                 goto fail;
3080                 }
3081         }
3082         return 0;
3083 fail:
3084         return ret;
3085 }
3086
3087 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3088                   struct extent_buffer *buf, int full_backref, int for_cow)
3089 {
3090         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
3091 }
3092
3093 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3094                   struct extent_buffer *buf, int full_backref, int for_cow)
3095 {
3096         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
3097 }
3098
3099 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3100                                  struct btrfs_root *root,
3101                                  struct btrfs_path *path,
3102                                  struct btrfs_block_group_cache *cache)
3103 {
3104         int ret;
3105         struct btrfs_root *extent_root = root->fs_info->extent_root;
3106         unsigned long bi;
3107         struct extent_buffer *leaf;
3108
3109         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3110         if (ret < 0)
3111                 goto fail;
3112         BUG_ON(ret); /* Corruption */
3113
3114         leaf = path->nodes[0];
3115         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3116         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3117         btrfs_mark_buffer_dirty(leaf);
3118         btrfs_release_path(path);
3119 fail:
3120         if (ret) {
3121                 btrfs_abort_transaction(trans, root, ret);
3122                 return ret;
3123         }
3124         return 0;
3125
3126 }
3127
3128 static struct btrfs_block_group_cache *
3129 next_block_group(struct btrfs_root *root,
3130                  struct btrfs_block_group_cache *cache)
3131 {
3132         struct rb_node *node;
3133         spin_lock(&root->fs_info->block_group_cache_lock);
3134         node = rb_next(&cache->cache_node);
3135         btrfs_put_block_group(cache);
3136         if (node) {
3137                 cache = rb_entry(node, struct btrfs_block_group_cache,
3138                                  cache_node);
3139                 btrfs_get_block_group(cache);
3140         } else
3141                 cache = NULL;
3142         spin_unlock(&root->fs_info->block_group_cache_lock);
3143         return cache;
3144 }
3145
3146 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3147                             struct btrfs_trans_handle *trans,
3148                             struct btrfs_path *path)
3149 {
3150         struct btrfs_root *root = block_group->fs_info->tree_root;
3151         struct inode *inode = NULL;
3152         u64 alloc_hint = 0;
3153         int dcs = BTRFS_DC_ERROR;
3154         int num_pages = 0;
3155         int retries = 0;
3156         int ret = 0;
3157
3158         /*
3159          * If this block group is smaller than 100 megs don't bother caching the
3160          * block group.
3161          */
3162         if (block_group->key.offset < (100 * 1024 * 1024)) {
3163                 spin_lock(&block_group->lock);
3164                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3165                 spin_unlock(&block_group->lock);
3166                 return 0;
3167         }
3168
3169 again:
3170         inode = lookup_free_space_inode(root, block_group, path);
3171         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3172                 ret = PTR_ERR(inode);
3173                 btrfs_release_path(path);
3174                 goto out;
3175         }
3176
3177         if (IS_ERR(inode)) {
3178                 BUG_ON(retries);
3179                 retries++;
3180
3181                 if (block_group->ro)
3182                         goto out_free;
3183
3184                 ret = create_free_space_inode(root, trans, block_group, path);
3185                 if (ret)
3186                         goto out_free;
3187                 goto again;
3188         }
3189
3190         /* We've already setup this transaction, go ahead and exit */
3191         if (block_group->cache_generation == trans->transid &&
3192             i_size_read(inode)) {
3193                 dcs = BTRFS_DC_SETUP;
3194                 goto out_put;
3195         }
3196
3197         /*
3198          * We want to set the generation to 0, that way if anything goes wrong
3199          * from here on out we know not to trust this cache when we load up next
3200          * time.
3201          */
3202         BTRFS_I(inode)->generation = 0;
3203         ret = btrfs_update_inode(trans, root, inode);
3204         WARN_ON(ret);
3205
3206         if (i_size_read(inode) > 0) {
3207                 ret = btrfs_check_trunc_cache_free_space(root,
3208                                         &root->fs_info->global_block_rsv);
3209                 if (ret)
3210                         goto out_put;
3211
3212                 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3213                 if (ret)
3214                         goto out_put;
3215         }
3216
3217         spin_lock(&block_group->lock);
3218         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3219             !btrfs_test_opt(root, SPACE_CACHE)) {
3220                 /*
3221                  * don't bother trying to write stuff out _if_
3222                  * a) we're not cached,
3223                  * b) we're with nospace_cache mount option.
3224                  */
3225                 dcs = BTRFS_DC_WRITTEN;
3226                 spin_unlock(&block_group->lock);
3227                 goto out_put;
3228         }
3229         spin_unlock(&block_group->lock);
3230
3231         /*
3232          * Try to preallocate enough space based on how big the block group is.
3233          * Keep in mind this has to include any pinned space which could end up
3234          * taking up quite a bit since it's not folded into the other space
3235          * cache.
3236          */
3237         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3238         if (!num_pages)
3239                 num_pages = 1;
3240
3241         num_pages *= 16;
3242         num_pages *= PAGE_CACHE_SIZE;
3243
3244         ret = btrfs_check_data_free_space(inode, num_pages);
3245         if (ret)
3246                 goto out_put;
3247
3248         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3249                                               num_pages, num_pages,
3250                                               &alloc_hint);
3251         if (!ret)
3252                 dcs = BTRFS_DC_SETUP;
3253         btrfs_free_reserved_data_space(inode, num_pages);
3254
3255 out_put:
3256         iput(inode);
3257 out_free:
3258         btrfs_release_path(path);
3259 out:
3260         spin_lock(&block_group->lock);
3261         if (!ret && dcs == BTRFS_DC_SETUP)
3262                 block_group->cache_generation = trans->transid;
3263         block_group->disk_cache_state = dcs;
3264         spin_unlock(&block_group->lock);
3265
3266         return ret;
3267 }
3268
3269 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3270                                    struct btrfs_root *root)
3271 {
3272         struct btrfs_block_group_cache *cache;
3273         int err = 0;
3274         struct btrfs_path *path;
3275         u64 last = 0;
3276
3277         path = btrfs_alloc_path();
3278         if (!path)
3279                 return -ENOMEM;
3280
3281 again:
3282         while (1) {
3283                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3284                 while (cache) {
3285                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3286                                 break;
3287                         cache = next_block_group(root, cache);
3288                 }
3289                 if (!cache) {
3290                         if (last == 0)
3291                                 break;
3292                         last = 0;
3293                         continue;
3294                 }
3295                 err = cache_save_setup(cache, trans, path);
3296                 last = cache->key.objectid + cache->key.offset;
3297                 btrfs_put_block_group(cache);
3298         }
3299
3300         while (1) {
3301                 if (last == 0) {
3302                         err = btrfs_run_delayed_refs(trans, root,
3303                                                      (unsigned long)-1);
3304                         if (err) /* File system offline */
3305                                 goto out;
3306                 }
3307
3308                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3309                 while (cache) {
3310                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3311                                 btrfs_put_block_group(cache);
3312                                 goto again;
3313                         }
3314
3315                         if (cache->dirty)
3316                                 break;
3317                         cache = next_block_group(root, cache);
3318                 }
3319                 if (!cache) {
3320                         if (last == 0)
3321                                 break;
3322                         last = 0;
3323                         continue;
3324                 }
3325
3326                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3327                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3328                 cache->dirty = 0;
3329                 last = cache->key.objectid + cache->key.offset;
3330
3331                 err = write_one_cache_group(trans, root, path, cache);
3332                 btrfs_put_block_group(cache);
3333                 if (err) /* File system offline */
3334                         goto out;
3335         }
3336
3337         while (1) {
3338                 /*
3339                  * I don't think this is needed since we're just marking our
3340                  * preallocated extent as written, but just in case it can't
3341                  * hurt.
3342                  */
3343                 if (last == 0) {
3344                         err = btrfs_run_delayed_refs(trans, root,
3345                                                      (unsigned long)-1);
3346                         if (err) /* File system offline */
3347                                 goto out;
3348                 }
3349
3350                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3351                 while (cache) {
3352                         /*
3353                          * Really this shouldn't happen, but it could if we
3354                          * couldn't write the entire preallocated extent and
3355                          * splitting the extent resulted in a new block.
3356                          */
3357                         if (cache->dirty) {
3358                                 btrfs_put_block_group(cache);
3359                                 goto again;
3360                         }
3361                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3362                                 break;
3363                         cache = next_block_group(root, cache);
3364                 }
3365                 if (!cache) {
3366                         if (last == 0)
3367                                 break;
3368                         last = 0;
3369                         continue;
3370                 }
3371
3372                 err = btrfs_write_out_cache(root, trans, cache, path);
3373
3374                 /*
3375                  * If we didn't have an error then the cache state is still
3376                  * NEED_WRITE, so we can set it to WRITTEN.
3377                  */
3378                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3379                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3380                 last = cache->key.objectid + cache->key.offset;
3381                 btrfs_put_block_group(cache);
3382         }
3383 out:
3384
3385         btrfs_free_path(path);
3386         return err;
3387 }
3388
3389 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3390 {
3391         struct btrfs_block_group_cache *block_group;
3392         int readonly = 0;
3393
3394         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3395         if (!block_group || block_group->ro)
3396                 readonly = 1;
3397         if (block_group)
3398                 btrfs_put_block_group(block_group);
3399         return readonly;
3400 }
3401
3402 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3403                              u64 total_bytes, u64 bytes_used,
3404                              struct btrfs_space_info **space_info)
3405 {
3406         struct btrfs_space_info *found;
3407         int i;
3408         int factor;
3409         int ret;
3410
3411         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3412                      BTRFS_BLOCK_GROUP_RAID10))
3413                 factor = 2;
3414         else
3415                 factor = 1;
3416
3417         found = __find_space_info(info, flags);
3418         if (found) {
3419                 spin_lock(&found->lock);
3420                 found->total_bytes += total_bytes;
3421                 found->disk_total += total_bytes * factor;
3422                 found->bytes_used += bytes_used;
3423                 found->disk_used += bytes_used * factor;
3424                 found->full = 0;
3425                 spin_unlock(&found->lock);
3426                 *space_info = found;
3427                 return 0;
3428         }
3429         found = kzalloc(sizeof(*found), GFP_NOFS);
3430         if (!found)
3431                 return -ENOMEM;
3432
3433         ret = percpu_counter_init(&found->total_bytes_pinned, 0);
3434         if (ret) {
3435                 kfree(found);
3436                 return ret;
3437         }
3438
3439         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3440                 INIT_LIST_HEAD(&found->block_groups[i]);
3441         init_rwsem(&found->groups_sem);
3442         spin_lock_init(&found->lock);
3443         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3444         found->total_bytes = total_bytes;
3445         found->disk_total = total_bytes * factor;
3446         found->bytes_used = bytes_used;
3447         found->disk_used = bytes_used * factor;
3448         found->bytes_pinned = 0;
3449         found->bytes_reserved = 0;
3450         found->bytes_readonly = 0;
3451         found->bytes_may_use = 0;
3452         found->full = 0;
3453         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3454         found->chunk_alloc = 0;
3455         found->flush = 0;
3456         init_waitqueue_head(&found->wait);
3457         *space_info = found;
3458         list_add_rcu(&found->list, &info->space_info);
3459         if (flags & BTRFS_BLOCK_GROUP_DATA)
3460                 info->data_sinfo = found;
3461         return 0;
3462 }
3463
3464 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3465 {
3466         u64 extra_flags = chunk_to_extended(flags) &
3467                                 BTRFS_EXTENDED_PROFILE_MASK;
3468
3469         write_seqlock(&fs_info->profiles_lock);
3470         if (flags & BTRFS_BLOCK_GROUP_DATA)
3471                 fs_info->avail_data_alloc_bits |= extra_flags;
3472         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3473                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3474         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3475                 fs_info->avail_system_alloc_bits |= extra_flags;
3476         write_sequnlock(&fs_info->profiles_lock);
3477 }
3478
3479 /*
3480  * returns target flags in extended format or 0 if restripe for this
3481  * chunk_type is not in progress
3482  *
3483  * should be called with either volume_mutex or balance_lock held
3484  */
3485 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3486 {
3487         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3488         u64 target = 0;
3489
3490         if (!bctl)
3491                 return 0;
3492
3493         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3494             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3495                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3496         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3497                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3498                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3499         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3500                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3501                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3502         }
3503
3504         return target;
3505 }
3506
3507 /*
3508  * @flags: available profiles in extended format (see ctree.h)
3509  *
3510  * Returns reduced profile in chunk format.  If profile changing is in
3511  * progress (either running or paused) picks the target profile (if it's
3512  * already available), otherwise falls back to plain reducing.
3513  */
3514 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3515 {
3516         /*
3517          * we add in the count of missing devices because we want
3518          * to make sure that any RAID levels on a degraded FS
3519          * continue to be honored.
3520          */
3521         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3522                 root->fs_info->fs_devices->missing_devices;
3523         u64 target;
3524         u64 tmp;
3525
3526         /*
3527          * see if restripe for this chunk_type is in progress, if so
3528          * try to reduce to the target profile
3529          */
3530         spin_lock(&root->fs_info->balance_lock);
3531         target = get_restripe_target(root->fs_info, flags);
3532         if (target) {
3533                 /* pick target profile only if it's already available */
3534                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3535                         spin_unlock(&root->fs_info->balance_lock);
3536                         return extended_to_chunk(target);
3537                 }
3538         }
3539         spin_unlock(&root->fs_info->balance_lock);
3540
3541         /* First, mask out the RAID levels which aren't possible */
3542         if (num_devices == 1)
3543                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3544                            BTRFS_BLOCK_GROUP_RAID5);
3545         if (num_devices < 3)
3546                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3547         if (num_devices < 4)
3548                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3549
3550         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3551                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3552                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3553         flags &= ~tmp;
3554
3555         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3556                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3557         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3558                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3559         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3560                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3561         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3562                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3563         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3564                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3565
3566         return extended_to_chunk(flags | tmp);
3567 }
3568
3569 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3570 {
3571         unsigned seq;
3572
3573         do {
3574                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3575
3576                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3577                         flags |= root->fs_info->avail_data_alloc_bits;
3578                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3579                         flags |= root->fs_info->avail_system_alloc_bits;
3580                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3581                         flags |= root->fs_info->avail_metadata_alloc_bits;
3582         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3583
3584         return btrfs_reduce_alloc_profile(root, flags);
3585 }
3586
3587 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3588 {
3589         u64 flags;
3590         u64 ret;
3591
3592         if (data)
3593                 flags = BTRFS_BLOCK_GROUP_DATA;
3594         else if (root == root->fs_info->chunk_root)
3595                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3596         else
3597                 flags = BTRFS_BLOCK_GROUP_METADATA;
3598
3599         ret = get_alloc_profile(root, flags);
3600         return ret;
3601 }
3602
3603 /*
3604  * This will check the space that the inode allocates from to make sure we have
3605  * enough space for bytes.
3606  */
3607 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3608 {
3609         struct btrfs_space_info *data_sinfo;
3610         struct btrfs_root *root = BTRFS_I(inode)->root;
3611         struct btrfs_fs_info *fs_info = root->fs_info;
3612         u64 used;
3613         int ret = 0, committed = 0, alloc_chunk = 1;
3614
3615         /* make sure bytes are sectorsize aligned */
3616         bytes = ALIGN(bytes, root->sectorsize);
3617
3618         if (root == root->fs_info->tree_root ||
3619             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3620                 alloc_chunk = 0;
3621                 committed = 1;
3622         }
3623
3624         data_sinfo = fs_info->data_sinfo;
3625         if (!data_sinfo)
3626                 goto alloc;
3627
3628 again:
3629         /* make sure we have enough space to handle the data first */
3630         spin_lock(&data_sinfo->lock);
3631         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3632                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3633                 data_sinfo->bytes_may_use;
3634
3635         if (used + bytes > data_sinfo->total_bytes) {
3636                 struct btrfs_trans_handle *trans;
3637
3638                 /*
3639                  * if we don't have enough free bytes in this space then we need
3640                  * to alloc a new chunk.
3641                  */
3642                 if (!data_sinfo->full && alloc_chunk) {
3643                         u64 alloc_target;
3644
3645                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3646                         spin_unlock(&data_sinfo->lock);
3647 alloc:
3648                         alloc_target = btrfs_get_alloc_profile(root, 1);
3649                         trans = btrfs_join_transaction(root);
3650                         if (IS_ERR(trans))
3651                                 return PTR_ERR(trans);
3652
3653                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3654                                              alloc_target,
3655                                              CHUNK_ALLOC_NO_FORCE);
3656                         btrfs_end_transaction(trans, root);
3657                         if (ret < 0) {
3658                                 if (ret != -ENOSPC)
3659                                         return ret;
3660                                 else
3661                                         goto commit_trans;
3662                         }
3663
3664                         if (!data_sinfo)
3665                                 data_sinfo = fs_info->data_sinfo;
3666
3667                         goto again;
3668                 }
3669
3670                 /*
3671                  * If we don't have enough pinned space to deal with this
3672                  * allocation don't bother committing the transaction.
3673                  */
3674                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
3675                                            bytes) < 0)
3676                         committed = 1;
3677                 spin_unlock(&data_sinfo->lock);
3678
3679                 /* commit the current transaction and try again */
3680 commit_trans:
3681                 if (!committed &&
3682                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3683                         committed = 1;
3684
3685                         trans = btrfs_join_transaction(root);
3686                         if (IS_ERR(trans))
3687                                 return PTR_ERR(trans);
3688                         ret = btrfs_commit_transaction(trans, root);
3689                         if (ret)
3690                                 return ret;
3691                         goto again;
3692                 }
3693
3694                 return -ENOSPC;
3695         }
3696         data_sinfo->bytes_may_use += bytes;
3697         trace_btrfs_space_reservation(root->fs_info, "space_info",
3698                                       data_sinfo->flags, bytes, 1);
3699         spin_unlock(&data_sinfo->lock);
3700
3701         return 0;
3702 }
3703
3704 /*
3705  * Called if we need to clear a data reservation for this inode.
3706  */
3707 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3708 {
3709         struct btrfs_root *root = BTRFS_I(inode)->root;
3710         struct btrfs_space_info *data_sinfo;
3711
3712         /* make sure bytes are sectorsize aligned */
3713         bytes = ALIGN(bytes, root->sectorsize);
3714
3715         data_sinfo = root->fs_info->data_sinfo;
3716         spin_lock(&data_sinfo->lock);
3717         WARN_ON(data_sinfo->bytes_may_use < bytes);
3718         data_sinfo->bytes_may_use -= bytes;
3719         trace_btrfs_space_reservation(root->fs_info, "space_info",
3720                                       data_sinfo->flags, bytes, 0);
3721         spin_unlock(&data_sinfo->lock);
3722 }
3723
3724 static void force_metadata_allocation(struct btrfs_fs_info *info)
3725 {
3726         struct list_head *head = &info->space_info;
3727         struct btrfs_space_info *found;
3728
3729         rcu_read_lock();
3730         list_for_each_entry_rcu(found, head, list) {
3731                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3732                         found->force_alloc = CHUNK_ALLOC_FORCE;
3733         }
3734         rcu_read_unlock();
3735 }
3736
3737 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3738 {
3739         return (global->size << 1);
3740 }
3741
3742 static int should_alloc_chunk(struct btrfs_root *root,
3743                               struct btrfs_space_info *sinfo, int force)
3744 {
3745         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3746         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3747         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3748         u64 thresh;
3749
3750         if (force == CHUNK_ALLOC_FORCE)
3751                 return 1;
3752
3753         /*
3754          * We need to take into account the global rsv because for all intents
3755          * and purposes it's used space.  Don't worry about locking the
3756          * global_rsv, it doesn't change except when the transaction commits.
3757          */
3758         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3759                 num_allocated += calc_global_rsv_need_space(global_rsv);
3760
3761         /*
3762          * in limited mode, we want to have some free space up to
3763          * about 1% of the FS size.
3764          */
3765         if (force == CHUNK_ALLOC_LIMITED) {
3766                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3767                 thresh = max_t(u64, 64 * 1024 * 1024,
3768                                div_factor_fine(thresh, 1));
3769
3770                 if (num_bytes - num_allocated < thresh)
3771                         return 1;
3772         }
3773
3774         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3775                 return 0;
3776         return 1;
3777 }
3778
3779 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3780 {
3781         u64 num_dev;
3782
3783         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3784                     BTRFS_BLOCK_GROUP_RAID0 |
3785                     BTRFS_BLOCK_GROUP_RAID5 |
3786                     BTRFS_BLOCK_GROUP_RAID6))
3787                 num_dev = root->fs_info->fs_devices->rw_devices;
3788         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3789                 num_dev = 2;
3790         else
3791                 num_dev = 1;    /* DUP or single */
3792
3793         /* metadata for updaing devices and chunk tree */
3794         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3795 }
3796
3797 static void check_system_chunk(struct btrfs_trans_handle *trans,
3798                                struct btrfs_root *root, u64 type)
3799 {
3800         struct btrfs_space_info *info;
3801         u64 left;
3802         u64 thresh;
3803
3804         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3805         spin_lock(&info->lock);
3806         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3807                 info->bytes_reserved - info->bytes_readonly;
3808         spin_unlock(&info->lock);
3809
3810         thresh = get_system_chunk_thresh(root, type);
3811         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3812                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3813                         left, thresh, type);
3814                 dump_space_info(info, 0, 0);
3815         }
3816
3817         if (left < thresh) {
3818                 u64 flags;
3819
3820                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3821                 btrfs_alloc_chunk(trans, root, flags);
3822         }
3823 }
3824
3825 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3826                           struct btrfs_root *extent_root, u64 flags, int force)
3827 {
3828         struct btrfs_space_info *space_info;
3829         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3830         int wait_for_alloc = 0;
3831         int ret = 0;
3832
3833         /* Don't re-enter if we're already allocating a chunk */
3834         if (trans->allocating_chunk)
3835                 return -ENOSPC;
3836
3837         space_info = __find_space_info(extent_root->fs_info, flags);
3838         if (!space_info) {
3839                 ret = update_space_info(extent_root->fs_info, flags,
3840                                         0, 0, &space_info);
3841                 BUG_ON(ret); /* -ENOMEM */
3842         }
3843         BUG_ON(!space_info); /* Logic error */
3844
3845 again:
3846         spin_lock(&space_info->lock);
3847         if (force < space_info->force_alloc)
3848                 force = space_info->force_alloc;
3849         if (space_info->full) {
3850                 if (should_alloc_chunk(extent_root, space_info, force))
3851                         ret = -ENOSPC;
3852                 else
3853                         ret = 0;
3854                 spin_unlock(&space_info->lock);
3855                 return ret;
3856         }
3857
3858         if (!should_alloc_chunk(extent_root, space_info, force)) {
3859                 spin_unlock(&space_info->lock);
3860                 return 0;
3861         } else if (space_info->chunk_alloc) {
3862                 wait_for_alloc = 1;
3863         } else {
3864                 space_info->chunk_alloc = 1;
3865         }
3866
3867         spin_unlock(&space_info->lock);
3868
3869         mutex_lock(&fs_info->chunk_mutex);
3870
3871         /*
3872          * The chunk_mutex is held throughout the entirety of a chunk
3873          * allocation, so once we've acquired the chunk_mutex we know that the
3874          * other guy is done and we need to recheck and see if we should
3875          * allocate.
3876          */
3877         if (wait_for_alloc) {
3878                 mutex_unlock(&fs_info->chunk_mutex);
3879                 wait_for_alloc = 0;
3880                 goto again;
3881         }
3882
3883         trans->allocating_chunk = true;
3884
3885         /*
3886          * If we have mixed data/metadata chunks we want to make sure we keep
3887          * allocating mixed chunks instead of individual chunks.
3888          */
3889         if (btrfs_mixed_space_info(space_info))
3890                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3891
3892         /*
3893          * if we're doing a data chunk, go ahead and make sure that
3894          * we keep a reasonable number of metadata chunks allocated in the
3895          * FS as well.
3896          */
3897         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3898                 fs_info->data_chunk_allocations++;
3899                 if (!(fs_info->data_chunk_allocations %
3900                       fs_info->metadata_ratio))
3901                         force_metadata_allocation(fs_info);
3902         }
3903
3904         /*
3905          * Check if we have enough space in SYSTEM chunk because we may need
3906          * to update devices.
3907          */
3908         check_system_chunk(trans, extent_root, flags);
3909
3910         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3911         trans->allocating_chunk = false;
3912
3913         spin_lock(&space_info->lock);
3914         if (ret < 0 && ret != -ENOSPC)
3915                 goto out;
3916         if (ret)
3917                 space_info->full = 1;
3918         else
3919                 ret = 1;
3920
3921         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3922 out:
3923         space_info->chunk_alloc = 0;
3924         spin_unlock(&space_info->lock);
3925         mutex_unlock(&fs_info->chunk_mutex);
3926         return ret;
3927 }
3928
3929 static int can_overcommit(struct btrfs_root *root,
3930                           struct btrfs_space_info *space_info, u64 bytes,
3931                           enum btrfs_reserve_flush_enum flush)
3932 {
3933         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3934         u64 profile = btrfs_get_alloc_profile(root, 0);
3935         u64 space_size;
3936         u64 avail;
3937         u64 used;
3938
3939         used = space_info->bytes_used + space_info->bytes_reserved +
3940                 space_info->bytes_pinned + space_info->bytes_readonly;
3941
3942         /*
3943          * We only want to allow over committing if we have lots of actual space
3944          * free, but if we don't have enough space to handle the global reserve
3945          * space then we could end up having a real enospc problem when trying
3946          * to allocate a chunk or some other such important allocation.
3947          */
3948         spin_lock(&global_rsv->lock);
3949         space_size = calc_global_rsv_need_space(global_rsv);
3950         spin_unlock(&global_rsv->lock);
3951         if (used + space_size >= space_info->total_bytes)
3952                 return 0;
3953
3954         used += space_info->bytes_may_use;
3955
3956         spin_lock(&root->fs_info->free_chunk_lock);
3957         avail = root->fs_info->free_chunk_space;
3958         spin_unlock(&root->fs_info->free_chunk_lock);
3959
3960         /*
3961          * If we have dup, raid1 or raid10 then only half of the free
3962          * space is actually useable.  For raid56, the space info used
3963          * doesn't include the parity drive, so we don't have to
3964          * change the math
3965          */
3966         if (profile & (BTRFS_BLOCK_GROUP_DUP |
3967                        BTRFS_BLOCK_GROUP_RAID1 |
3968                        BTRFS_BLOCK_GROUP_RAID10))
3969                 avail >>= 1;
3970
3971         /*
3972          * If we aren't flushing all things, let us overcommit up to
3973          * 1/2th of the space. If we can flush, don't let us overcommit
3974          * too much, let it overcommit up to 1/8 of the space.
3975          */
3976         if (flush == BTRFS_RESERVE_FLUSH_ALL)
3977                 avail >>= 3;
3978         else
3979                 avail >>= 1;
3980
3981         if (used + bytes < space_info->total_bytes + avail)
3982                 return 1;
3983         return 0;
3984 }
3985
3986 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
3987                                          unsigned long nr_pages)
3988 {
3989         struct super_block *sb = root->fs_info->sb;
3990
3991         if (down_read_trylock(&sb->s_umount)) {
3992                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
3993                 up_read(&sb->s_umount);
3994         } else {
3995                 /*
3996                  * We needn't worry the filesystem going from r/w to r/o though
3997                  * we don't acquire ->s_umount mutex, because the filesystem
3998                  * should guarantee the delalloc inodes list be empty after
3999                  * the filesystem is readonly(all dirty pages are written to
4000                  * the disk).
4001                  */
4002                 btrfs_start_all_delalloc_inodes(root->fs_info, 0);
4003                 if (!current->journal_info)
4004                         btrfs_wait_all_ordered_extents(root->fs_info);
4005         }
4006 }
4007
4008 /*
4009  * shrink metadata reservation for delalloc
4010  */
4011 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4012                             bool wait_ordered)
4013 {
4014         struct btrfs_block_rsv *block_rsv;
4015         struct btrfs_space_info *space_info;
4016         struct btrfs_trans_handle *trans;
4017         u64 delalloc_bytes;
4018         u64 max_reclaim;
4019         long time_left;
4020         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
4021         int loops = 0;
4022         enum btrfs_reserve_flush_enum flush;
4023
4024         trans = (struct btrfs_trans_handle *)current->journal_info;
4025         block_rsv = &root->fs_info->delalloc_block_rsv;
4026         space_info = block_rsv->space_info;
4027
4028         smp_mb();
4029         delalloc_bytes = percpu_counter_sum_positive(
4030                                                 &root->fs_info->delalloc_bytes);
4031         if (delalloc_bytes == 0) {
4032                 if (trans)
4033                         return;
4034                 btrfs_wait_all_ordered_extents(root->fs_info);
4035                 return;
4036         }
4037
4038         while (delalloc_bytes && loops < 3) {
4039                 max_reclaim = min(delalloc_bytes, to_reclaim);
4040                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4041                 btrfs_writeback_inodes_sb_nr(root, nr_pages);
4042                 /*
4043                  * We need to wait for the async pages to actually start before
4044                  * we do anything.
4045                  */
4046                 wait_event(root->fs_info->async_submit_wait,
4047                            !atomic_read(&root->fs_info->async_delalloc_pages));
4048
4049                 if (!trans)
4050                         flush = BTRFS_RESERVE_FLUSH_ALL;
4051                 else
4052                         flush = BTRFS_RESERVE_NO_FLUSH;
4053                 spin_lock(&space_info->lock);
4054                 if (can_overcommit(root, space_info, orig, flush)) {
4055                         spin_unlock(&space_info->lock);
4056                         break;
4057                 }
4058                 spin_unlock(&space_info->lock);
4059
4060                 loops++;
4061                 if (wait_ordered && !trans) {
4062                         btrfs_wait_all_ordered_extents(root->fs_info);
4063                 } else {
4064                         time_left = schedule_timeout_killable(1);
4065                         if (time_left)
4066                                 break;
4067                 }
4068                 smp_mb();
4069                 delalloc_bytes = percpu_counter_sum_positive(
4070                                                 &root->fs_info->delalloc_bytes);
4071         }
4072 }
4073
4074 /**
4075  * maybe_commit_transaction - possibly commit the transaction if its ok to
4076  * @root - the root we're allocating for
4077  * @bytes - the number of bytes we want to reserve
4078  * @force - force the commit
4079  *
4080  * This will check to make sure that committing the transaction will actually
4081  * get us somewhere and then commit the transaction if it does.  Otherwise it
4082  * will return -ENOSPC.
4083  */
4084 static int may_commit_transaction(struct btrfs_root *root,
4085                                   struct btrfs_space_info *space_info,
4086                                   u64 bytes, int force)
4087 {
4088         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4089         struct btrfs_trans_handle *trans;
4090
4091         trans = (struct btrfs_trans_handle *)current->journal_info;
4092         if (trans)
4093                 return -EAGAIN;
4094
4095         if (force)
4096                 goto commit;
4097
4098         /* See if there is enough pinned space to make this reservation */
4099         spin_lock(&space_info->lock);
4100         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4101                                    bytes) >= 0) {
4102                 spin_unlock(&space_info->lock);
4103                 goto commit;
4104         }
4105         spin_unlock(&space_info->lock);
4106
4107         /*
4108          * See if there is some space in the delayed insertion reservation for
4109          * this reservation.
4110          */
4111         if (space_info != delayed_rsv->space_info)
4112                 return -ENOSPC;
4113
4114         spin_lock(&space_info->lock);
4115         spin_lock(&delayed_rsv->lock);
4116         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4117                                    bytes - delayed_rsv->size) >= 0) {
4118                 spin_unlock(&delayed_rsv->lock);
4119                 spin_unlock(&space_info->lock);
4120                 return -ENOSPC;
4121         }
4122         spin_unlock(&delayed_rsv->lock);
4123         spin_unlock(&space_info->lock);
4124
4125 commit:
4126         trans = btrfs_join_transaction(root);
4127         if (IS_ERR(trans))
4128                 return -ENOSPC;
4129
4130         return btrfs_commit_transaction(trans, root);
4131 }
4132
4133 enum flush_state {
4134         FLUSH_DELAYED_ITEMS_NR  =       1,
4135         FLUSH_DELAYED_ITEMS     =       2,
4136         FLUSH_DELALLOC          =       3,
4137         FLUSH_DELALLOC_WAIT     =       4,
4138         ALLOC_CHUNK             =       5,
4139         COMMIT_TRANS            =       6,
4140 };
4141
4142 static int flush_space(struct btrfs_root *root,
4143                        struct btrfs_space_info *space_info, u64 num_bytes,
4144                        u64 orig_bytes, int state)
4145 {
4146         struct btrfs_trans_handle *trans;
4147         int nr;
4148         int ret = 0;
4149
4150         switch (state) {
4151         case FLUSH_DELAYED_ITEMS_NR:
4152         case FLUSH_DELAYED_ITEMS:
4153                 if (state == FLUSH_DELAYED_ITEMS_NR) {
4154                         u64 bytes = btrfs_calc_trans_metadata_size(root, 1);
4155
4156                         nr = (int)div64_u64(num_bytes, bytes);
4157                         if (!nr)
4158                                 nr = 1;
4159                         nr *= 2;
4160                 } else {
4161                         nr = -1;
4162                 }
4163                 trans = btrfs_join_transaction(root);
4164                 if (IS_ERR(trans)) {
4165                         ret = PTR_ERR(trans);
4166                         break;
4167                 }
4168                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4169                 btrfs_end_transaction(trans, root);
4170                 break;
4171         case FLUSH_DELALLOC:
4172         case FLUSH_DELALLOC_WAIT:
4173                 shrink_delalloc(root, num_bytes, orig_bytes,
4174                                 state == FLUSH_DELALLOC_WAIT);
4175                 break;
4176         case ALLOC_CHUNK:
4177                 trans = btrfs_join_transaction(root);
4178                 if (IS_ERR(trans)) {
4179                         ret = PTR_ERR(trans);
4180                         break;
4181                 }
4182                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4183                                      btrfs_get_alloc_profile(root, 0),
4184                                      CHUNK_ALLOC_NO_FORCE);
4185                 btrfs_end_transaction(trans, root);
4186                 if (ret == -ENOSPC)
4187                         ret = 0;
4188                 break;
4189         case COMMIT_TRANS:
4190                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4191                 break;
4192         default:
4193                 ret = -ENOSPC;
4194                 break;
4195         }
4196
4197         return ret;
4198 }
4199 /**
4200  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4201  * @root - the root we're allocating for
4202  * @block_rsv - the block_rsv we're allocating for
4203  * @orig_bytes - the number of bytes we want
4204  * @flush - whether or not we can flush to make our reservation
4205  *
4206  * This will reserve orgi_bytes number of bytes from the space info associated
4207  * with the block_rsv.  If there is not enough space it will make an attempt to
4208  * flush out space to make room.  It will do this by flushing delalloc if
4209  * possible or committing the transaction.  If flush is 0 then no attempts to
4210  * regain reservations will be made and this will fail if there is not enough
4211  * space already.
4212  */
4213 static int reserve_metadata_bytes(struct btrfs_root *root,
4214                                   struct btrfs_block_rsv *block_rsv,
4215                                   u64 orig_bytes,
4216                                   enum btrfs_reserve_flush_enum flush)
4217 {
4218         struct btrfs_space_info *space_info = block_rsv->space_info;
4219         u64 used;
4220         u64 num_bytes = orig_bytes;
4221         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4222         int ret = 0;
4223         bool flushing = false;
4224
4225 again:
4226         ret = 0;
4227         spin_lock(&space_info->lock);
4228         /*
4229          * We only want to wait if somebody other than us is flushing and we
4230          * are actually allowed to flush all things.
4231          */
4232         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4233                space_info->flush) {
4234                 spin_unlock(&space_info->lock);
4235                 /*
4236                  * If we have a trans handle we can't wait because the flusher
4237                  * may have to commit the transaction, which would mean we would
4238                  * deadlock since we are waiting for the flusher to finish, but
4239                  * hold the current transaction open.
4240                  */
4241                 if (current->journal_info)
4242                         return -EAGAIN;
4243                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4244                 /* Must have been killed, return */
4245                 if (ret)
4246                         return -EINTR;
4247
4248                 spin_lock(&space_info->lock);
4249         }
4250
4251         ret = -ENOSPC;
4252         used = space_info->bytes_used + space_info->bytes_reserved +
4253                 space_info->bytes_pinned + space_info->bytes_readonly +
4254                 space_info->bytes_may_use;
4255
4256         /*
4257          * The idea here is that we've not already over-reserved the block group
4258          * then we can go ahead and save our reservation first and then start
4259          * flushing if we need to.  Otherwise if we've already overcommitted
4260          * lets start flushing stuff first and then come back and try to make
4261          * our reservation.
4262          */
4263         if (used <= space_info->total_bytes) {
4264                 if (used + orig_bytes <= space_info->total_bytes) {
4265                         space_info->bytes_may_use += orig_bytes;
4266                         trace_btrfs_space_reservation(root->fs_info,
4267                                 "space_info", space_info->flags, orig_bytes, 1);
4268                         ret = 0;
4269                 } else {
4270                         /*
4271                          * Ok set num_bytes to orig_bytes since we aren't
4272                          * overocmmitted, this way we only try and reclaim what
4273                          * we need.
4274                          */
4275                         num_bytes = orig_bytes;
4276                 }
4277         } else {
4278                 /*
4279                  * Ok we're over committed, set num_bytes to the overcommitted
4280                  * amount plus the amount of bytes that we need for this
4281                  * reservation.
4282                  */
4283                 num_bytes = used - space_info->total_bytes +
4284                         (orig_bytes * 2);
4285         }
4286
4287         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4288                 space_info->bytes_may_use += orig_bytes;
4289                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4290                                               space_info->flags, orig_bytes,
4291                                               1);
4292                 ret = 0;
4293         }
4294
4295         /*
4296          * Couldn't make our reservation, save our place so while we're trying
4297          * to reclaim space we can actually use it instead of somebody else
4298          * stealing it from us.
4299          *
4300          * We make the other tasks wait for the flush only when we can flush
4301          * all things.
4302          */
4303         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4304                 flushing = true;
4305                 space_info->flush = 1;
4306         }
4307
4308         spin_unlock(&space_info->lock);
4309
4310         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4311                 goto out;
4312
4313         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4314                           flush_state);
4315         flush_state++;
4316
4317         /*
4318          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4319          * would happen. So skip delalloc flush.
4320          */
4321         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4322             (flush_state == FLUSH_DELALLOC ||
4323              flush_state == FLUSH_DELALLOC_WAIT))
4324                 flush_state = ALLOC_CHUNK;
4325
4326         if (!ret)
4327                 goto again;
4328         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4329                  flush_state < COMMIT_TRANS)
4330                 goto again;
4331         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4332                  flush_state <= COMMIT_TRANS)
4333                 goto again;
4334
4335 out:
4336         if (ret == -ENOSPC &&
4337             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4338                 struct btrfs_block_rsv *global_rsv =
4339                         &root->fs_info->global_block_rsv;
4340
4341                 if (block_rsv != global_rsv &&
4342                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4343                         ret = 0;
4344         }
4345         if (flushing) {
4346                 spin_lock(&space_info->lock);
4347                 space_info->flush = 0;
4348                 wake_up_all(&space_info->wait);
4349                 spin_unlock(&space_info->lock);
4350         }
4351         return ret;
4352 }
4353
4354 static struct btrfs_block_rsv *get_block_rsv(
4355                                         const struct btrfs_trans_handle *trans,
4356                                         const struct btrfs_root *root)
4357 {
4358         struct btrfs_block_rsv *block_rsv = NULL;
4359
4360         if (root->ref_cows)
4361                 block_rsv = trans->block_rsv;
4362
4363         if (root == root->fs_info->csum_root && trans->adding_csums)
4364                 block_rsv = trans->block_rsv;
4365
4366         if (root == root->fs_info->uuid_root)
4367                 block_rsv = trans->block_rsv;
4368
4369         if (!block_rsv)
4370                 block_rsv = root->block_rsv;
4371
4372         if (!block_rsv)
4373                 block_rsv = &root->fs_info->empty_block_rsv;
4374
4375         return block_rsv;
4376 }
4377
4378 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4379                                u64 num_bytes)
4380 {
4381         int ret = -ENOSPC;
4382         spin_lock(&block_rsv->lock);
4383         if (block_rsv->reserved >= num_bytes) {
4384                 block_rsv->reserved -= num_bytes;
4385                 if (block_rsv->reserved < block_rsv->size)
4386                         block_rsv->full = 0;
4387                 ret = 0;
4388         }
4389         spin_unlock(&block_rsv->lock);
4390         return ret;
4391 }
4392
4393 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4394                                 u64 num_bytes, int update_size)
4395 {
4396         spin_lock(&block_rsv->lock);
4397         block_rsv->reserved += num_bytes;
4398         if (update_size)
4399                 block_rsv->size += num_bytes;
4400         else if (block_rsv->reserved >= block_rsv->size)
4401                 block_rsv->full = 1;
4402         spin_unlock(&block_rsv->lock);
4403 }
4404
4405 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4406                              struct btrfs_block_rsv *dest, u64 num_bytes,
4407                              int min_factor)
4408 {
4409         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4410         u64 min_bytes;
4411
4412         if (global_rsv->space_info != dest->space_info)
4413                 return -ENOSPC;
4414
4415         spin_lock(&global_rsv->lock);
4416         min_bytes = div_factor(global_rsv->size, min_factor);
4417         if (global_rsv->reserved < min_bytes + num_bytes) {
4418                 spin_unlock(&global_rsv->lock);
4419                 return -ENOSPC;
4420         }
4421         global_rsv->reserved -= num_bytes;
4422         if (global_rsv->reserved < global_rsv->size)
4423                 global_rsv->full = 0;
4424         spin_unlock(&global_rsv->lock);
4425
4426         block_rsv_add_bytes(dest, num_bytes, 1);
4427         return 0;
4428 }
4429
4430 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4431                                     struct btrfs_block_rsv *block_rsv,
4432                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4433 {
4434         struct btrfs_space_info *space_info = block_rsv->space_info;
4435
4436         spin_lock(&block_rsv->lock);
4437         if (num_bytes == (u64)-1)
4438                 num_bytes = block_rsv->size;
4439         block_rsv->size -= num_bytes;
4440         if (block_rsv->reserved >= block_rsv->size) {
4441                 num_bytes = block_rsv->reserved - block_rsv->size;
4442                 block_rsv->reserved = block_rsv->size;
4443                 block_rsv->full = 1;
4444         } else {
4445                 num_bytes = 0;
4446         }
4447         spin_unlock(&block_rsv->lock);
4448
4449         if (num_bytes > 0) {
4450                 if (dest) {
4451                         spin_lock(&dest->lock);
4452                         if (!dest->full) {
4453                                 u64 bytes_to_add;
4454
4455                                 bytes_to_add = dest->size - dest->reserved;
4456                                 bytes_to_add = min(num_bytes, bytes_to_add);
4457                                 dest->reserved += bytes_to_add;
4458                                 if (dest->reserved >= dest->size)
4459                                         dest->full = 1;
4460                                 num_bytes -= bytes_to_add;
4461                         }
4462                         spin_unlock(&dest->lock);
4463                 }
4464                 if (num_bytes) {
4465                         spin_lock(&space_info->lock);
4466                         space_info->bytes_may_use -= num_bytes;
4467                         trace_btrfs_space_reservation(fs_info, "space_info",
4468                                         space_info->flags, num_bytes, 0);
4469                         spin_unlock(&space_info->lock);
4470                 }
4471         }
4472 }
4473
4474 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4475                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4476 {
4477         int ret;
4478
4479         ret = block_rsv_use_bytes(src, num_bytes);
4480         if (ret)
4481                 return ret;
4482
4483         block_rsv_add_bytes(dst, num_bytes, 1);
4484         return 0;
4485 }
4486
4487 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4488 {
4489         memset(rsv, 0, sizeof(*rsv));
4490         spin_lock_init(&rsv->lock);
4491         rsv->type = type;
4492 }
4493
4494 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4495                                               unsigned short type)
4496 {
4497         struct btrfs_block_rsv *block_rsv;
4498         struct btrfs_fs_info *fs_info = root->fs_info;
4499
4500         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4501         if (!block_rsv)
4502                 return NULL;
4503
4504         btrfs_init_block_rsv(block_rsv, type);
4505         block_rsv->space_info = __find_space_info(fs_info,
4506                                                   BTRFS_BLOCK_GROUP_METADATA);
4507         return block_rsv;
4508 }
4509
4510 void btrfs_free_block_rsv(struct btrfs_root *root,
4511                           struct btrfs_block_rsv *rsv)
4512 {
4513         if (!rsv)
4514                 return;
4515         btrfs_block_rsv_release(root, rsv, (u64)-1);
4516         kfree(rsv);
4517 }
4518
4519 int btrfs_block_rsv_add(struct btrfs_root *root,
4520                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4521                         enum btrfs_reserve_flush_enum flush)
4522 {
4523         int ret;
4524
4525         if (num_bytes == 0)
4526                 return 0;
4527
4528         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4529         if (!ret) {
4530                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4531                 return 0;
4532         }
4533
4534         return ret;
4535 }
4536
4537 int btrfs_block_rsv_check(struct btrfs_root *root,
4538                           struct btrfs_block_rsv *block_rsv, int min_factor)
4539 {
4540         u64 num_bytes = 0;
4541         int ret = -ENOSPC;
4542
4543         if (!block_rsv)
4544                 return 0;
4545
4546         spin_lock(&block_rsv->lock);
4547         num_bytes = div_factor(block_rsv->size, min_factor);
4548         if (block_rsv->reserved >= num_bytes)
4549                 ret = 0;
4550         spin_unlock(&block_rsv->lock);
4551
4552         return ret;
4553 }
4554
4555 int btrfs_block_rsv_refill(struct btrfs_root *root,
4556                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4557                            enum btrfs_reserve_flush_enum flush)
4558 {
4559         u64 num_bytes = 0;
4560         int ret = -ENOSPC;
4561
4562         if (!block_rsv)
4563                 return 0;
4564
4565         spin_lock(&block_rsv->lock);
4566         num_bytes = min_reserved;
4567         if (block_rsv->reserved >= num_bytes)
4568                 ret = 0;
4569         else
4570                 num_bytes -= block_rsv->reserved;
4571         spin_unlock(&block_rsv->lock);
4572
4573         if (!ret)
4574                 return 0;
4575
4576         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4577         if (!ret) {
4578                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4579                 return 0;
4580         }
4581
4582         return ret;
4583 }
4584
4585 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4586                             struct btrfs_block_rsv *dst_rsv,
4587                             u64 num_bytes)
4588 {
4589         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4590 }
4591
4592 void btrfs_block_rsv_release(struct btrfs_root *root,
4593                              struct btrfs_block_rsv *block_rsv,
4594                              u64 num_bytes)
4595 {
4596         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4597         if (global_rsv->full || global_rsv == block_rsv ||
4598             block_rsv->space_info != global_rsv->space_info)
4599                 global_rsv = NULL;
4600         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4601                                 num_bytes);
4602 }
4603
4604 /*
4605  * helper to calculate size of global block reservation.
4606  * the desired value is sum of space used by extent tree,
4607  * checksum tree and root tree
4608  */
4609 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4610 {
4611         struct btrfs_space_info *sinfo;
4612         u64 num_bytes;
4613         u64 meta_used;
4614         u64 data_used;
4615         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4616
4617         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4618         spin_lock(&sinfo->lock);
4619         data_used = sinfo->bytes_used;
4620         spin_unlock(&sinfo->lock);
4621
4622         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4623         spin_lock(&sinfo->lock);
4624         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4625                 data_used = 0;
4626         meta_used = sinfo->bytes_used;
4627         spin_unlock(&sinfo->lock);
4628
4629         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4630                     csum_size * 2;
4631         num_bytes += div64_u64(data_used + meta_used, 50);
4632
4633         if (num_bytes * 3 > meta_used)
4634                 num_bytes = div64_u64(meta_used, 3);
4635
4636         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4637 }
4638
4639 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4640 {
4641         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4642         struct btrfs_space_info *sinfo = block_rsv->space_info;
4643         u64 num_bytes;
4644
4645         num_bytes = calc_global_metadata_size(fs_info);
4646
4647         spin_lock(&sinfo->lock);
4648         spin_lock(&block_rsv->lock);
4649
4650         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4651
4652         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4653                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4654                     sinfo->bytes_may_use;
4655
4656         if (sinfo->total_bytes > num_bytes) {
4657                 num_bytes = sinfo->total_bytes - num_bytes;
4658                 block_rsv->reserved += num_bytes;
4659                 sinfo->bytes_may_use += num_bytes;
4660                 trace_btrfs_space_reservation(fs_info, "space_info",
4661                                       sinfo->flags, num_bytes, 1);
4662         }
4663
4664         if (block_rsv->reserved >= block_rsv->size) {
4665                 num_bytes = block_rsv->reserved - block_rsv->size;
4666                 sinfo->bytes_may_use -= num_bytes;
4667                 trace_btrfs_space_reservation(fs_info, "space_info",
4668                                       sinfo->flags, num_bytes, 0);
4669                 block_rsv->reserved = block_rsv->size;
4670                 block_rsv->full = 1;
4671         }
4672
4673         spin_unlock(&block_rsv->lock);
4674         spin_unlock(&sinfo->lock);
4675 }
4676
4677 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4678 {
4679         struct btrfs_space_info *space_info;
4680
4681         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4682         fs_info->chunk_block_rsv.space_info = space_info;
4683
4684         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4685         fs_info->global_block_rsv.space_info = space_info;
4686         fs_info->delalloc_block_rsv.space_info = space_info;
4687         fs_info->trans_block_rsv.space_info = space_info;
4688         fs_info->empty_block_rsv.space_info = space_info;
4689         fs_info->delayed_block_rsv.space_info = space_info;
4690
4691         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4692         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4693         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4694         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4695         if (fs_info->quota_root)
4696                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4697         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4698
4699         update_global_block_rsv(fs_info);
4700 }
4701
4702 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4703 {
4704         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4705                                 (u64)-1);
4706         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4707         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4708         WARN_ON(fs_info->trans_block_rsv.size > 0);
4709         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4710         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4711         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4712         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4713         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4714 }
4715
4716 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4717                                   struct btrfs_root *root)
4718 {
4719         if (!trans->block_rsv)
4720                 return;
4721
4722         if (!trans->bytes_reserved)
4723                 return;
4724
4725         trace_btrfs_space_reservation(root->fs_info, "transaction",
4726                                       trans->transid, trans->bytes_reserved, 0);
4727         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4728         trans->bytes_reserved = 0;
4729 }
4730
4731 /* Can only return 0 or -ENOSPC */
4732 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4733                                   struct inode *inode)
4734 {
4735         struct btrfs_root *root = BTRFS_I(inode)->root;
4736         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4737         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4738
4739         /*
4740          * We need to hold space in order to delete our orphan item once we've
4741          * added it, so this takes the reservation so we can release it later
4742          * when we are truly done with the orphan item.
4743          */
4744         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4745         trace_btrfs_space_reservation(root->fs_info, "orphan",
4746                                       btrfs_ino(inode), num_bytes, 1);
4747         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4748 }
4749
4750 void btrfs_orphan_release_metadata(struct inode *inode)
4751 {
4752         struct btrfs_root *root = BTRFS_I(inode)->root;
4753         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4754         trace_btrfs_space_reservation(root->fs_info, "orphan",
4755                                       btrfs_ino(inode), num_bytes, 0);
4756         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4757 }
4758
4759 /*
4760  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4761  * root: the root of the parent directory
4762  * rsv: block reservation
4763  * items: the number of items that we need do reservation
4764  * qgroup_reserved: used to return the reserved size in qgroup
4765  *
4766  * This function is used to reserve the space for snapshot/subvolume
4767  * creation and deletion. Those operations are different with the
4768  * common file/directory operations, they change two fs/file trees
4769  * and root tree, the number of items that the qgroup reserves is
4770  * different with the free space reservation. So we can not use
4771  * the space reseravtion mechanism in start_transaction().
4772  */
4773 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4774                                      struct btrfs_block_rsv *rsv,
4775                                      int items,
4776                                      u64 *qgroup_reserved,
4777                                      bool use_global_rsv)
4778 {
4779         u64 num_bytes;
4780         int ret;
4781         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4782
4783         if (root->fs_info->quota_enabled) {
4784                 /* One for parent inode, two for dir entries */
4785                 num_bytes = 3 * root->leafsize;
4786                 ret = btrfs_qgroup_reserve(root, num_bytes);
4787                 if (ret)
4788                         return ret;
4789         } else {
4790                 num_bytes = 0;
4791         }
4792
4793         *qgroup_reserved = num_bytes;
4794
4795         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4796         rsv->space_info = __find_space_info(root->fs_info,
4797                                             BTRFS_BLOCK_GROUP_METADATA);
4798         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4799                                   BTRFS_RESERVE_FLUSH_ALL);
4800
4801         if (ret == -ENOSPC && use_global_rsv)
4802                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
4803
4804         if (ret) {
4805                 if (*qgroup_reserved)
4806                         btrfs_qgroup_free(root, *qgroup_reserved);
4807         }
4808
4809         return ret;
4810 }
4811
4812 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4813                                       struct btrfs_block_rsv *rsv,
4814                                       u64 qgroup_reserved)
4815 {
4816         btrfs_block_rsv_release(root, rsv, (u64)-1);
4817         if (qgroup_reserved)
4818                 btrfs_qgroup_free(root, qgroup_reserved);
4819 }
4820
4821 /**
4822  * drop_outstanding_extent - drop an outstanding extent
4823  * @inode: the inode we're dropping the extent for
4824  *
4825  * This is called when we are freeing up an outstanding extent, either called
4826  * after an error or after an extent is written.  This will return the number of
4827  * reserved extents that need to be freed.  This must be called with
4828  * BTRFS_I(inode)->lock held.
4829  */
4830 static unsigned drop_outstanding_extent(struct inode *inode)
4831 {
4832         unsigned drop_inode_space = 0;
4833         unsigned dropped_extents = 0;
4834
4835         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4836         BTRFS_I(inode)->outstanding_extents--;
4837
4838         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4839             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4840                                &BTRFS_I(inode)->runtime_flags))
4841                 drop_inode_space = 1;
4842
4843         /*
4844          * If we have more or the same amount of outsanding extents than we have
4845          * reserved then we need to leave the reserved extents count alone.
4846          */
4847         if (BTRFS_I(inode)->outstanding_extents >=
4848             BTRFS_I(inode)->reserved_extents)
4849                 return drop_inode_space;
4850
4851         dropped_extents = BTRFS_I(inode)->reserved_extents -
4852                 BTRFS_I(inode)->outstanding_extents;
4853         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4854         return dropped_extents + drop_inode_space;
4855 }
4856
4857 /**
4858  * calc_csum_metadata_size - return the amount of metada space that must be
4859  *      reserved/free'd for the given bytes.
4860  * @inode: the inode we're manipulating
4861  * @num_bytes: the number of bytes in question
4862  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4863  *
4864  * This adjusts the number of csum_bytes in the inode and then returns the
4865  * correct amount of metadata that must either be reserved or freed.  We
4866  * calculate how many checksums we can fit into one leaf and then divide the
4867  * number of bytes that will need to be checksumed by this value to figure out
4868  * how many checksums will be required.  If we are adding bytes then the number
4869  * may go up and we will return the number of additional bytes that must be
4870  * reserved.  If it is going down we will return the number of bytes that must
4871  * be freed.
4872  *
4873  * This must be called with BTRFS_I(inode)->lock held.
4874  */
4875 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4876                                    int reserve)
4877 {
4878         struct btrfs_root *root = BTRFS_I(inode)->root;
4879         u64 csum_size;
4880         int num_csums_per_leaf;
4881         int num_csums;
4882         int old_csums;
4883
4884         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4885             BTRFS_I(inode)->csum_bytes == 0)
4886                 return 0;
4887
4888         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4889         if (reserve)
4890                 BTRFS_I(inode)->csum_bytes += num_bytes;
4891         else
4892                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4893         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4894         num_csums_per_leaf = (int)div64_u64(csum_size,
4895                                             sizeof(struct btrfs_csum_item) +
4896                                             sizeof(struct btrfs_disk_key));
4897         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4898         num_csums = num_csums + num_csums_per_leaf - 1;
4899         num_csums = num_csums / num_csums_per_leaf;
4900
4901         old_csums = old_csums + num_csums_per_leaf - 1;
4902         old_csums = old_csums / num_csums_per_leaf;
4903
4904         /* No change, no need to reserve more */
4905         if (old_csums == num_csums)
4906                 return 0;
4907
4908         if (reserve)
4909                 return btrfs_calc_trans_metadata_size(root,
4910                                                       num_csums - old_csums);
4911
4912         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4913 }
4914
4915 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4916 {
4917         struct btrfs_root *root = BTRFS_I(inode)->root;
4918         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4919         u64 to_reserve = 0;
4920         u64 csum_bytes;
4921         unsigned nr_extents = 0;
4922         int extra_reserve = 0;
4923         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
4924         int ret = 0;
4925         bool delalloc_lock = true;
4926         u64 to_free = 0;
4927         unsigned dropped;
4928
4929         /* If we are a free space inode we need to not flush since we will be in
4930          * the middle of a transaction commit.  We also don't need the delalloc
4931          * mutex since we won't race with anybody.  We need this mostly to make
4932          * lockdep shut its filthy mouth.
4933          */
4934         if (btrfs_is_free_space_inode(inode)) {
4935                 flush = BTRFS_RESERVE_NO_FLUSH;
4936                 delalloc_lock = false;
4937         }
4938
4939         if (flush != BTRFS_RESERVE_NO_FLUSH &&
4940             btrfs_transaction_in_commit(root->fs_info))
4941                 schedule_timeout(1);
4942
4943         if (delalloc_lock)
4944                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4945
4946         num_bytes = ALIGN(num_bytes, root->sectorsize);
4947
4948         spin_lock(&BTRFS_I(inode)->lock);
4949         BTRFS_I(inode)->outstanding_extents++;
4950
4951         if (BTRFS_I(inode)->outstanding_extents >
4952             BTRFS_I(inode)->reserved_extents)
4953                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4954                         BTRFS_I(inode)->reserved_extents;
4955
4956         /*
4957          * Add an item to reserve for updating the inode when we complete the
4958          * delalloc io.
4959          */
4960         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4961                       &BTRFS_I(inode)->runtime_flags)) {
4962                 nr_extents++;
4963                 extra_reserve = 1;
4964         }
4965
4966         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4967         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4968         csum_bytes = BTRFS_I(inode)->csum_bytes;
4969         spin_unlock(&BTRFS_I(inode)->lock);
4970
4971         if (root->fs_info->quota_enabled) {
4972                 ret = btrfs_qgroup_reserve(root, num_bytes +
4973                                            nr_extents * root->leafsize);
4974                 if (ret)
4975                         goto out_fail;
4976         }
4977
4978         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4979         if (unlikely(ret)) {
4980                 if (root->fs_info->quota_enabled)
4981                         btrfs_qgroup_free(root, num_bytes +
4982                                                 nr_extents * root->leafsize);
4983                 goto out_fail;
4984         }
4985
4986         spin_lock(&BTRFS_I(inode)->lock);
4987         if (extra_reserve) {
4988                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4989                         &BTRFS_I(inode)->runtime_flags);
4990                 nr_extents--;
4991         }
4992         BTRFS_I(inode)->reserved_extents += nr_extents;
4993         spin_unlock(&BTRFS_I(inode)->lock);
4994
4995         if (delalloc_lock)
4996                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4997
4998         if (to_reserve)
4999                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
5000                                               btrfs_ino(inode), to_reserve, 1);
5001         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5002
5003         return 0;
5004
5005 out_fail:
5006         spin_lock(&BTRFS_I(inode)->lock);
5007         dropped = drop_outstanding_extent(inode);
5008         /*
5009          * If the inodes csum_bytes is the same as the original
5010          * csum_bytes then we know we haven't raced with any free()ers
5011          * so we can just reduce our inodes csum bytes and carry on.
5012          */
5013         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5014                 calc_csum_metadata_size(inode, num_bytes, 0);
5015         } else {
5016                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5017                 u64 bytes;
5018
5019                 /*
5020                  * This is tricky, but first we need to figure out how much we
5021                  * free'd from any free-ers that occured during this
5022                  * reservation, so we reset ->csum_bytes to the csum_bytes
5023                  * before we dropped our lock, and then call the free for the
5024                  * number of bytes that were freed while we were trying our
5025                  * reservation.
5026                  */
5027                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5028                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5029                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5030
5031
5032                 /*
5033                  * Now we need to see how much we would have freed had we not
5034                  * been making this reservation and our ->csum_bytes were not
5035                  * artificially inflated.
5036                  */
5037                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5038                 bytes = csum_bytes - orig_csum_bytes;
5039                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5040
5041                 /*
5042                  * Now reset ->csum_bytes to what it should be.  If bytes is
5043                  * more than to_free then we would have free'd more space had we
5044                  * not had an artificially high ->csum_bytes, so we need to free
5045                  * the remainder.  If bytes is the same or less then we don't
5046                  * need to do anything, the other free-ers did the correct
5047                  * thing.
5048                  */
5049                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5050                 if (bytes > to_free)
5051                         to_free = bytes - to_free;
5052                 else
5053                         to_free = 0;
5054         }
5055         spin_unlock(&BTRFS_I(inode)->lock);
5056         if (dropped)
5057                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5058
5059         if (to_free) {
5060                 btrfs_block_rsv_release(root, block_rsv, to_free);
5061                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5062                                               btrfs_ino(inode), to_free, 0);
5063         }
5064         if (delalloc_lock)
5065                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5066         return ret;
5067 }
5068
5069 /**
5070  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5071  * @inode: the inode to release the reservation for
5072  * @num_bytes: the number of bytes we're releasing
5073  *
5074  * This will release the metadata reservation for an inode.  This can be called
5075  * once we complete IO for a given set of bytes to release their metadata
5076  * reservations.
5077  */
5078 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5079 {
5080         struct btrfs_root *root = BTRFS_I(inode)->root;
5081         u64 to_free = 0;
5082         unsigned dropped;
5083
5084         num_bytes = ALIGN(num_bytes, root->sectorsize);
5085         spin_lock(&BTRFS_I(inode)->lock);
5086         dropped = drop_outstanding_extent(inode);
5087
5088         if (num_bytes)
5089                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5090         spin_unlock(&BTRFS_I(inode)->lock);
5091         if (dropped > 0)
5092                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5093
5094         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5095                                       btrfs_ino(inode), to_free, 0);
5096         if (root->fs_info->quota_enabled) {
5097                 btrfs_qgroup_free(root, num_bytes +
5098                                         dropped * root->leafsize);
5099         }
5100
5101         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5102                                 to_free);
5103 }
5104
5105 /**
5106  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5107  * @inode: inode we're writing to
5108  * @num_bytes: the number of bytes we want to allocate
5109  *
5110  * This will do the following things
5111  *
5112  * o reserve space in the data space info for num_bytes
5113  * o reserve space in the metadata space info based on number of outstanding
5114  *   extents and how much csums will be needed
5115  * o add to the inodes ->delalloc_bytes
5116  * o add it to the fs_info's delalloc inodes list.
5117  *
5118  * This will return 0 for success and -ENOSPC if there is no space left.
5119  */
5120 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5121 {
5122         int ret;
5123
5124         ret = btrfs_check_data_free_space(inode, num_bytes);
5125         if (ret)
5126                 return ret;
5127
5128         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5129         if (ret) {
5130                 btrfs_free_reserved_data_space(inode, num_bytes);
5131                 return ret;
5132         }
5133
5134         return 0;
5135 }
5136
5137 /**
5138  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5139  * @inode: inode we're releasing space for
5140  * @num_bytes: the number of bytes we want to free up
5141  *
5142  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5143  * called in the case that we don't need the metadata AND data reservations
5144  * anymore.  So if there is an error or we insert an inline extent.
5145  *
5146  * This function will release the metadata space that was not used and will
5147  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5148  * list if there are no delalloc bytes left.
5149  */
5150 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5151 {
5152         btrfs_delalloc_release_metadata(inode, num_bytes);
5153         btrfs_free_reserved_data_space(inode, num_bytes);
5154 }
5155
5156 static int update_block_group(struct btrfs_root *root,
5157                               u64 bytenr, u64 num_bytes, int alloc)
5158 {
5159         struct btrfs_block_group_cache *cache = NULL;
5160         struct btrfs_fs_info *info = root->fs_info;
5161         u64 total = num_bytes;
5162         u64 old_val;
5163         u64 byte_in_group;
5164         int factor;
5165
5166         /* block accounting for super block */
5167         spin_lock(&info->delalloc_root_lock);
5168         old_val = btrfs_super_bytes_used(info->super_copy);
5169         if (alloc)
5170                 old_val += num_bytes;
5171         else
5172                 old_val -= num_bytes;
5173         btrfs_set_super_bytes_used(info->super_copy, old_val);
5174         spin_unlock(&info->delalloc_root_lock);
5175
5176         while (total) {
5177                 cache = btrfs_lookup_block_group(info, bytenr);
5178                 if (!cache)
5179                         return -ENOENT;
5180                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5181                                     BTRFS_BLOCK_GROUP_RAID1 |
5182                                     BTRFS_BLOCK_GROUP_RAID10))
5183                         factor = 2;
5184                 else
5185                         factor = 1;
5186                 /*
5187                  * If this block group has free space cache written out, we
5188                  * need to make sure to load it if we are removing space.  This
5189                  * is because we need the unpinning stage to actually add the
5190                  * space back to the block group, otherwise we will leak space.
5191                  */
5192                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5193                         cache_block_group(cache, 1);
5194
5195                 byte_in_group = bytenr - cache->key.objectid;
5196                 WARN_ON(byte_in_group > cache->key.offset);
5197
5198                 spin_lock(&cache->space_info->lock);
5199                 spin_lock(&cache->lock);
5200
5201                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5202                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5203                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5204
5205                 cache->dirty = 1;
5206                 old_val = btrfs_block_group_used(&cache->item);
5207                 num_bytes = min(total, cache->key.offset - byte_in_group);
5208                 if (alloc) {
5209                         old_val += num_bytes;
5210                         btrfs_set_block_group_used(&cache->item, old_val);
5211                         cache->reserved -= num_bytes;
5212                         cache->space_info->bytes_reserved -= num_bytes;
5213                         cache->space_info->bytes_used += num_bytes;
5214                         cache->space_info->disk_used += num_bytes * factor;
5215                         spin_unlock(&cache->lock);
5216                         spin_unlock(&cache->space_info->lock);
5217                 } else {
5218                         old_val -= num_bytes;
5219                         btrfs_set_block_group_used(&cache->item, old_val);
5220                         cache->pinned += num_bytes;
5221                         cache->space_info->bytes_pinned += num_bytes;
5222                         cache->space_info->bytes_used -= num_bytes;
5223                         cache->space_info->disk_used -= num_bytes * factor;
5224                         spin_unlock(&cache->lock);
5225                         spin_unlock(&cache->space_info->lock);
5226
5227                         set_extent_dirty(info->pinned_extents,
5228                                          bytenr, bytenr + num_bytes - 1,
5229                                          GFP_NOFS | __GFP_NOFAIL);
5230                 }
5231                 btrfs_put_block_group(cache);
5232                 total -= num_bytes;
5233                 bytenr += num_bytes;
5234         }
5235         return 0;
5236 }
5237
5238 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5239 {
5240         struct btrfs_block_group_cache *cache;
5241         u64 bytenr;
5242
5243         spin_lock(&root->fs_info->block_group_cache_lock);
5244         bytenr = root->fs_info->first_logical_byte;
5245         spin_unlock(&root->fs_info->block_group_cache_lock);
5246
5247         if (bytenr < (u64)-1)
5248                 return bytenr;
5249
5250         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5251         if (!cache)
5252                 return 0;
5253
5254         bytenr = cache->key.objectid;
5255         btrfs_put_block_group(cache);
5256
5257         return bytenr;
5258 }
5259
5260 static int pin_down_extent(struct btrfs_root *root,
5261                            struct btrfs_block_group_cache *cache,
5262                            u64 bytenr, u64 num_bytes, int reserved)
5263 {
5264         spin_lock(&cache->space_info->lock);
5265         spin_lock(&cache->lock);
5266         cache->pinned += num_bytes;
5267         cache->space_info->bytes_pinned += num_bytes;
5268         if (reserved) {
5269                 cache->reserved -= num_bytes;
5270                 cache->space_info->bytes_reserved -= num_bytes;
5271         }
5272         spin_unlock(&cache->lock);
5273         spin_unlock(&cache->space_info->lock);
5274
5275         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5276                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5277         if (reserved)
5278                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5279         return 0;
5280 }
5281
5282 /*
5283  * this function must be called within transaction
5284  */
5285 int btrfs_pin_extent(struct btrfs_root *root,
5286                      u64 bytenr, u64 num_bytes, int reserved)
5287 {
5288         struct btrfs_block_group_cache *cache;
5289
5290         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5291         BUG_ON(!cache); /* Logic error */
5292
5293         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5294
5295         btrfs_put_block_group(cache);
5296         return 0;
5297 }
5298
5299 /*
5300  * this function must be called within transaction
5301  */
5302 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5303                                     u64 bytenr, u64 num_bytes)
5304 {
5305         struct btrfs_block_group_cache *cache;
5306         int ret;
5307
5308         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5309         if (!cache)
5310                 return -EINVAL;
5311
5312         /*
5313          * pull in the free space cache (if any) so that our pin
5314          * removes the free space from the cache.  We have load_only set
5315          * to one because the slow code to read in the free extents does check
5316          * the pinned extents.
5317          */
5318         cache_block_group(cache, 1);
5319
5320         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5321
5322         /* remove us from the free space cache (if we're there at all) */
5323         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5324         btrfs_put_block_group(cache);
5325         return ret;
5326 }
5327
5328 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5329 {
5330         int ret;
5331         struct btrfs_block_group_cache *block_group;
5332         struct btrfs_caching_control *caching_ctl;
5333
5334         block_group = btrfs_lookup_block_group(root->fs_info, start);
5335         if (!block_group)
5336                 return -EINVAL;
5337
5338         cache_block_group(block_group, 0);
5339         caching_ctl = get_caching_control(block_group);
5340
5341         if (!caching_ctl) {
5342                 /* Logic error */
5343                 BUG_ON(!block_group_cache_done(block_group));
5344                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5345         } else {
5346                 mutex_lock(&caching_ctl->mutex);
5347
5348                 if (start >= caching_ctl->progress) {
5349                         ret = add_excluded_extent(root, start, num_bytes);
5350                 } else if (start + num_bytes <= caching_ctl->progress) {
5351                         ret = btrfs_remove_free_space(block_group,
5352                                                       start, num_bytes);
5353                 } else {
5354                         num_bytes = caching_ctl->progress - start;
5355                         ret = btrfs_remove_free_space(block_group,
5356                                                       start, num_bytes);
5357                         if (ret)
5358                                 goto out_lock;
5359
5360                         num_bytes = (start + num_bytes) -
5361                                 caching_ctl->progress;
5362                         start = caching_ctl->progress;
5363                         ret = add_excluded_extent(root, start, num_bytes);
5364                 }
5365 out_lock:
5366                 mutex_unlock(&caching_ctl->mutex);
5367                 put_caching_control(caching_ctl);
5368         }
5369         btrfs_put_block_group(block_group);
5370         return ret;
5371 }
5372
5373 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5374                                  struct extent_buffer *eb)
5375 {
5376         struct btrfs_file_extent_item *item;
5377         struct btrfs_key key;
5378         int found_type;
5379         int i;
5380
5381         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5382                 return 0;
5383
5384         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5385                 btrfs_item_key_to_cpu(eb, &key, i);
5386                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5387                         continue;
5388                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5389                 found_type = btrfs_file_extent_type(eb, item);
5390                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5391                         continue;
5392                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5393                         continue;
5394                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5395                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5396                 __exclude_logged_extent(log, key.objectid, key.offset);
5397         }
5398
5399         return 0;
5400 }
5401
5402 /**
5403  * btrfs_update_reserved_bytes - update the block_group and space info counters
5404  * @cache:      The cache we are manipulating
5405  * @num_bytes:  The number of bytes in question
5406  * @reserve:    One of the reservation enums
5407  *
5408  * This is called by the allocator when it reserves space, or by somebody who is
5409  * freeing space that was never actually used on disk.  For example if you
5410  * reserve some space for a new leaf in transaction A and before transaction A
5411  * commits you free that leaf, you call this with reserve set to 0 in order to
5412  * clear the reservation.
5413  *
5414  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5415  * ENOSPC accounting.  For data we handle the reservation through clearing the
5416  * delalloc bits in the io_tree.  We have to do this since we could end up
5417  * allocating less disk space for the amount of data we have reserved in the
5418  * case of compression.
5419  *
5420  * If this is a reservation and the block group has become read only we cannot
5421  * make the reservation and return -EAGAIN, otherwise this function always
5422  * succeeds.
5423  */
5424 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5425                                        u64 num_bytes, int reserve)
5426 {
5427         struct btrfs_space_info *space_info = cache->space_info;
5428         int ret = 0;
5429
5430         spin_lock(&space_info->lock);
5431         spin_lock(&cache->lock);
5432         if (reserve != RESERVE_FREE) {
5433                 if (cache->ro) {
5434                         ret = -EAGAIN;
5435                 } else {
5436                         cache->reserved += num_bytes;
5437                         space_info->bytes_reserved += num_bytes;
5438                         if (reserve == RESERVE_ALLOC) {
5439                                 trace_btrfs_space_reservation(cache->fs_info,
5440                                                 "space_info", space_info->flags,
5441                                                 num_bytes, 0);
5442                                 space_info->bytes_may_use -= num_bytes;
5443                         }
5444                 }
5445         } else {
5446                 if (cache->ro)
5447                         space_info->bytes_readonly += num_bytes;
5448                 cache->reserved -= num_bytes;
5449                 space_info->bytes_reserved -= num_bytes;
5450         }
5451         spin_unlock(&cache->lock);
5452         spin_unlock(&space_info->lock);
5453         return ret;
5454 }
5455
5456 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5457                                 struct btrfs_root *root)
5458 {
5459         struct btrfs_fs_info *fs_info = root->fs_info;
5460         struct btrfs_caching_control *next;
5461         struct btrfs_caching_control *caching_ctl;
5462         struct btrfs_block_group_cache *cache;
5463         struct btrfs_space_info *space_info;
5464
5465         down_write(&fs_info->extent_commit_sem);
5466
5467         list_for_each_entry_safe(caching_ctl, next,
5468                                  &fs_info->caching_block_groups, list) {
5469                 cache = caching_ctl->block_group;
5470                 if (block_group_cache_done(cache)) {
5471                         cache->last_byte_to_unpin = (u64)-1;
5472                         list_del_init(&caching_ctl->list);
5473                         put_caching_control(caching_ctl);
5474                 } else {
5475                         cache->last_byte_to_unpin = caching_ctl->progress;
5476                 }
5477         }
5478
5479         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5480                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5481         else
5482                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5483
5484         up_write(&fs_info->extent_commit_sem);
5485
5486         list_for_each_entry_rcu(space_info, &fs_info->space_info, list)
5487                 percpu_counter_set(&space_info->total_bytes_pinned, 0);
5488
5489         update_global_block_rsv(fs_info);
5490 }
5491
5492 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5493 {
5494         struct btrfs_fs_info *fs_info = root->fs_info;
5495         struct btrfs_block_group_cache *cache = NULL;
5496         struct btrfs_space_info *space_info;
5497         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5498         u64 len;
5499         bool readonly;
5500
5501         while (start <= end) {
5502                 readonly = false;
5503                 if (!cache ||
5504                     start >= cache->key.objectid + cache->key.offset) {
5505                         if (cache)
5506                                 btrfs_put_block_group(cache);
5507                         cache = btrfs_lookup_block_group(fs_info, start);
5508                         BUG_ON(!cache); /* Logic error */
5509                 }
5510
5511                 len = cache->key.objectid + cache->key.offset - start;
5512                 len = min(len, end + 1 - start);
5513
5514                 if (start < cache->last_byte_to_unpin) {
5515                         len = min(len, cache->last_byte_to_unpin - start);
5516                         btrfs_add_free_space(cache, start, len);
5517                 }
5518
5519                 start += len;
5520                 space_info = cache->space_info;
5521
5522                 spin_lock(&space_info->lock);
5523                 spin_lock(&cache->lock);
5524                 cache->pinned -= len;
5525                 space_info->bytes_pinned -= len;
5526                 if (cache->ro) {
5527                         space_info->bytes_readonly += len;
5528                         readonly = true;
5529                 }
5530                 spin_unlock(&cache->lock);
5531                 if (!readonly && global_rsv->space_info == space_info) {
5532                         spin_lock(&global_rsv->lock);
5533                         if (!global_rsv->full) {
5534                                 len = min(len, global_rsv->size -
5535                                           global_rsv->reserved);
5536                                 global_rsv->reserved += len;
5537                                 space_info->bytes_may_use += len;
5538                                 if (global_rsv->reserved >= global_rsv->size)
5539                                         global_rsv->full = 1;
5540                         }
5541                         spin_unlock(&global_rsv->lock);
5542                 }
5543                 spin_unlock(&space_info->lock);
5544         }
5545
5546         if (cache)
5547                 btrfs_put_block_group(cache);
5548         return 0;
5549 }
5550
5551 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5552                                struct btrfs_root *root)
5553 {
5554         struct btrfs_fs_info *fs_info = root->fs_info;
5555         struct extent_io_tree *unpin;
5556         u64 start;
5557         u64 end;
5558         int ret;
5559
5560         if (trans->aborted)
5561                 return 0;
5562
5563         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5564                 unpin = &fs_info->freed_extents[1];
5565         else
5566                 unpin = &fs_info->freed_extents[0];
5567
5568         while (1) {
5569                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5570                                             EXTENT_DIRTY, NULL);
5571                 if (ret)
5572                         break;
5573
5574                 if (btrfs_test_opt(root, DISCARD))
5575                         ret = btrfs_discard_extent(root, start,
5576                                                    end + 1 - start, NULL);
5577
5578                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5579                 unpin_extent_range(root, start, end);
5580                 cond_resched();
5581         }
5582
5583         return 0;
5584 }
5585
5586 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
5587                              u64 owner, u64 root_objectid)
5588 {
5589         struct btrfs_space_info *space_info;
5590         u64 flags;
5591
5592         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5593                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
5594                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
5595                 else
5596                         flags = BTRFS_BLOCK_GROUP_METADATA;
5597         } else {
5598                 flags = BTRFS_BLOCK_GROUP_DATA;
5599         }
5600
5601         space_info = __find_space_info(fs_info, flags);
5602         BUG_ON(!space_info); /* Logic bug */
5603         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
5604 }
5605
5606
5607 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5608                                 struct btrfs_root *root,
5609                                 u64 bytenr, u64 num_bytes, u64 parent,
5610                                 u64 root_objectid, u64 owner_objectid,
5611                                 u64 owner_offset, int refs_to_drop,
5612                                 struct btrfs_delayed_extent_op *extent_op)
5613 {
5614         struct btrfs_key key;
5615         struct btrfs_path *path;
5616         struct btrfs_fs_info *info = root->fs_info;
5617         struct btrfs_root *extent_root = info->extent_root;
5618         struct extent_buffer *leaf;
5619         struct btrfs_extent_item *ei;
5620         struct btrfs_extent_inline_ref *iref;
5621         int ret;
5622         int is_data;
5623         int extent_slot = 0;
5624         int found_extent = 0;
5625         int num_to_del = 1;
5626         u32 item_size;
5627         u64 refs;
5628         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5629                                                  SKINNY_METADATA);
5630
5631         path = btrfs_alloc_path();
5632         if (!path)
5633                 return -ENOMEM;
5634
5635         path->reada = 1;
5636         path->leave_spinning = 1;
5637
5638         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5639         BUG_ON(!is_data && refs_to_drop != 1);
5640
5641         if (is_data)
5642                 skinny_metadata = 0;
5643
5644         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5645                                     bytenr, num_bytes, parent,
5646                                     root_objectid, owner_objectid,
5647                                     owner_offset);
5648         if (ret == 0) {
5649                 extent_slot = path->slots[0];
5650                 while (extent_slot >= 0) {
5651                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5652                                               extent_slot);
5653                         if (key.objectid != bytenr)
5654                                 break;
5655                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5656                             key.offset == num_bytes) {
5657                                 found_extent = 1;
5658                                 break;
5659                         }
5660                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5661                             key.offset == owner_objectid) {
5662                                 found_extent = 1;
5663                                 break;
5664                         }
5665                         if (path->slots[0] - extent_slot > 5)
5666                                 break;
5667                         extent_slot--;
5668                 }
5669 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5670                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5671                 if (found_extent && item_size < sizeof(*ei))
5672                         found_extent = 0;
5673 #endif
5674                 if (!found_extent) {
5675                         BUG_ON(iref);
5676                         ret = remove_extent_backref(trans, extent_root, path,
5677                                                     NULL, refs_to_drop,
5678                                                     is_data);
5679                         if (ret) {
5680                                 btrfs_abort_transaction(trans, extent_root, ret);
5681                                 goto out;
5682                         }
5683                         btrfs_release_path(path);
5684                         path->leave_spinning = 1;
5685
5686                         key.objectid = bytenr;
5687                         key.type = BTRFS_EXTENT_ITEM_KEY;
5688                         key.offset = num_bytes;
5689
5690                         if (!is_data && skinny_metadata) {
5691                                 key.type = BTRFS_METADATA_ITEM_KEY;
5692                                 key.offset = owner_objectid;
5693                         }
5694
5695                         ret = btrfs_search_slot(trans, extent_root,
5696                                                 &key, path, -1, 1);
5697                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5698                                 /*
5699                                  * Couldn't find our skinny metadata item,
5700                                  * see if we have ye olde extent item.
5701                                  */
5702                                 path->slots[0]--;
5703                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5704                                                       path->slots[0]);
5705                                 if (key.objectid == bytenr &&
5706                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5707                                     key.offset == num_bytes)
5708                                         ret = 0;
5709                         }
5710
5711                         if (ret > 0 && skinny_metadata) {
5712                                 skinny_metadata = false;
5713                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5714                                 key.offset = num_bytes;
5715                                 btrfs_release_path(path);
5716                                 ret = btrfs_search_slot(trans, extent_root,
5717                                                         &key, path, -1, 1);
5718                         }
5719
5720                         if (ret) {
5721                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5722                                         ret, bytenr);
5723                                 if (ret > 0)
5724                                         btrfs_print_leaf(extent_root,
5725                                                          path->nodes[0]);
5726                         }
5727                         if (ret < 0) {
5728                                 btrfs_abort_transaction(trans, extent_root, ret);
5729                                 goto out;
5730                         }
5731                         extent_slot = path->slots[0];
5732                 }
5733         } else if (ret == -ENOENT) {
5734                 btrfs_print_leaf(extent_root, path->nodes[0]);
5735                 WARN_ON(1);
5736                 btrfs_err(info,
5737                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5738                         bytenr, parent, root_objectid, owner_objectid,
5739                         owner_offset);
5740         } else {
5741                 btrfs_abort_transaction(trans, extent_root, ret);
5742                 goto out;
5743         }
5744
5745         leaf = path->nodes[0];
5746         item_size = btrfs_item_size_nr(leaf, extent_slot);
5747 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5748         if (item_size < sizeof(*ei)) {
5749                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5750                 ret = convert_extent_item_v0(trans, extent_root, path,
5751                                              owner_objectid, 0);
5752                 if (ret < 0) {
5753                         btrfs_abort_transaction(trans, extent_root, ret);
5754                         goto out;
5755                 }
5756
5757                 btrfs_release_path(path);
5758                 path->leave_spinning = 1;
5759
5760                 key.objectid = bytenr;
5761                 key.type = BTRFS_EXTENT_ITEM_KEY;
5762                 key.offset = num_bytes;
5763
5764                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5765                                         -1, 1);
5766                 if (ret) {
5767                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5768                                 ret, bytenr);
5769                         btrfs_print_leaf(extent_root, path->nodes[0]);
5770                 }
5771                 if (ret < 0) {
5772                         btrfs_abort_transaction(trans, extent_root, ret);
5773                         goto out;
5774                 }
5775
5776                 extent_slot = path->slots[0];
5777                 leaf = path->nodes[0];
5778                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5779         }
5780 #endif
5781         BUG_ON(item_size < sizeof(*ei));
5782         ei = btrfs_item_ptr(leaf, extent_slot,
5783                             struct btrfs_extent_item);
5784         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
5785             key.type == BTRFS_EXTENT_ITEM_KEY) {
5786                 struct btrfs_tree_block_info *bi;
5787                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5788                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5789                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5790         }
5791
5792         refs = btrfs_extent_refs(leaf, ei);
5793         if (refs < refs_to_drop) {
5794                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
5795                           "for bytenr %Lu\n", refs_to_drop, refs, bytenr);
5796                 ret = -EINVAL;
5797                 btrfs_abort_transaction(trans, extent_root, ret);
5798                 goto out;
5799         }
5800         refs -= refs_to_drop;
5801
5802         if (refs > 0) {
5803                 if (extent_op)
5804                         __run_delayed_extent_op(extent_op, leaf, ei);
5805                 /*
5806                  * In the case of inline back ref, reference count will
5807                  * be updated by remove_extent_backref
5808                  */
5809                 if (iref) {
5810                         BUG_ON(!found_extent);
5811                 } else {
5812                         btrfs_set_extent_refs(leaf, ei, refs);
5813                         btrfs_mark_buffer_dirty(leaf);
5814                 }
5815                 if (found_extent) {
5816                         ret = remove_extent_backref(trans, extent_root, path,
5817                                                     iref, refs_to_drop,
5818                                                     is_data);
5819                         if (ret) {
5820                                 btrfs_abort_transaction(trans, extent_root, ret);
5821                                 goto out;
5822                         }
5823                 }
5824                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
5825                                  root_objectid);
5826         } else {
5827                 if (found_extent) {
5828                         BUG_ON(is_data && refs_to_drop !=
5829                                extent_data_ref_count(root, path, iref));
5830                         if (iref) {
5831                                 BUG_ON(path->slots[0] != extent_slot);
5832                         } else {
5833                                 BUG_ON(path->slots[0] != extent_slot + 1);
5834                                 path->slots[0] = extent_slot;
5835                                 num_to_del = 2;
5836                         }
5837                 }
5838
5839                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5840                                       num_to_del);
5841                 if (ret) {
5842                         btrfs_abort_transaction(trans, extent_root, ret);
5843                         goto out;
5844                 }
5845                 btrfs_release_path(path);
5846
5847                 if (is_data) {
5848                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5849                         if (ret) {
5850                                 btrfs_abort_transaction(trans, extent_root, ret);
5851                                 goto out;
5852                         }
5853                 }
5854
5855                 ret = update_block_group(root, bytenr, num_bytes, 0);
5856                 if (ret) {
5857                         btrfs_abort_transaction(trans, extent_root, ret);
5858                         goto out;
5859                 }
5860         }
5861 out:
5862         btrfs_free_path(path);
5863         return ret;
5864 }
5865
5866 /*
5867  * when we free an block, it is possible (and likely) that we free the last
5868  * delayed ref for that extent as well.  This searches the delayed ref tree for
5869  * a given extent, and if there are no other delayed refs to be processed, it
5870  * removes it from the tree.
5871  */
5872 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5873                                       struct btrfs_root *root, u64 bytenr)
5874 {
5875         struct btrfs_delayed_ref_head *head;
5876         struct btrfs_delayed_ref_root *delayed_refs;
5877         struct btrfs_delayed_ref_node *ref;
5878         struct rb_node *node;
5879         int ret = 0;
5880
5881         delayed_refs = &trans->transaction->delayed_refs;
5882         spin_lock(&delayed_refs->lock);
5883         head = btrfs_find_delayed_ref_head(trans, bytenr);
5884         if (!head)
5885                 goto out;
5886
5887         node = rb_prev(&head->node.rb_node);
5888         if (!node)
5889                 goto out;
5890
5891         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5892
5893         /* there are still entries for this ref, we can't drop it */
5894         if (ref->bytenr == bytenr)
5895                 goto out;
5896
5897         if (head->extent_op) {
5898                 if (!head->must_insert_reserved)
5899                         goto out;
5900                 btrfs_free_delayed_extent_op(head->extent_op);
5901                 head->extent_op = NULL;
5902         }
5903
5904         /*
5905          * waiting for the lock here would deadlock.  If someone else has it
5906          * locked they are already in the process of dropping it anyway
5907          */
5908         if (!mutex_trylock(&head->mutex))
5909                 goto out;
5910
5911         /*
5912          * at this point we have a head with no other entries.  Go
5913          * ahead and process it.
5914          */
5915         head->node.in_tree = 0;
5916         rb_erase(&head->node.rb_node, &delayed_refs->root);
5917
5918         delayed_refs->num_entries--;
5919
5920         /*
5921          * we don't take a ref on the node because we're removing it from the
5922          * tree, so we just steal the ref the tree was holding.
5923          */
5924         delayed_refs->num_heads--;
5925         if (list_empty(&head->cluster))
5926                 delayed_refs->num_heads_ready--;
5927
5928         list_del_init(&head->cluster);
5929         spin_unlock(&delayed_refs->lock);
5930
5931         BUG_ON(head->extent_op);
5932         if (head->must_insert_reserved)
5933                 ret = 1;
5934
5935         mutex_unlock(&head->mutex);
5936         btrfs_put_delayed_ref(&head->node);
5937         return ret;
5938 out:
5939         spin_unlock(&delayed_refs->lock);
5940         return 0;
5941 }
5942
5943 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5944                            struct btrfs_root *root,
5945                            struct extent_buffer *buf,
5946                            u64 parent, int last_ref)
5947 {
5948         struct btrfs_block_group_cache *cache = NULL;
5949         int pin = 1;
5950         int ret;
5951
5952         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5953                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5954                                         buf->start, buf->len,
5955                                         parent, root->root_key.objectid,
5956                                         btrfs_header_level(buf),
5957                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5958                 BUG_ON(ret); /* -ENOMEM */
5959         }
5960
5961         if (!last_ref)
5962                 return;
5963
5964         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5965
5966         if (btrfs_header_generation(buf) == trans->transid) {
5967                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5968                         ret = check_ref_cleanup(trans, root, buf->start);
5969                         if (!ret)
5970                                 goto out;
5971                 }
5972
5973                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5974                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5975                         goto out;
5976                 }
5977
5978                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5979
5980                 btrfs_add_free_space(cache, buf->start, buf->len);
5981                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5982                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
5983                 pin = 0;
5984         }
5985 out:
5986         if (pin)
5987                 add_pinned_bytes(root->fs_info, buf->len,
5988                                  btrfs_header_level(buf),
5989                                  root->root_key.objectid);
5990
5991         /*
5992          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5993          * anymore.
5994          */
5995         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5996         btrfs_put_block_group(cache);
5997 }
5998
5999 /* Can return -ENOMEM */
6000 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6001                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6002                       u64 owner, u64 offset, int for_cow)
6003 {
6004         int ret;
6005         struct btrfs_fs_info *fs_info = root->fs_info;
6006
6007         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6008
6009         /*
6010          * tree log blocks never actually go into the extent allocation
6011          * tree, just update pinning info and exit early.
6012          */
6013         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6014                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6015                 /* unlocks the pinned mutex */
6016                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6017                 ret = 0;
6018         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6019                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6020                                         num_bytes,
6021                                         parent, root_objectid, (int)owner,
6022                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
6023         } else {
6024                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6025                                                 num_bytes,
6026                                                 parent, root_objectid, owner,
6027                                                 offset, BTRFS_DROP_DELAYED_REF,
6028                                                 NULL, for_cow);
6029         }
6030         return ret;
6031 }
6032
6033 static u64 stripe_align(struct btrfs_root *root,
6034                         struct btrfs_block_group_cache *cache,
6035                         u64 val, u64 num_bytes)
6036 {
6037         u64 ret = ALIGN(val, root->stripesize);
6038         return ret;
6039 }
6040
6041 /*
6042  * when we wait for progress in the block group caching, its because
6043  * our allocation attempt failed at least once.  So, we must sleep
6044  * and let some progress happen before we try again.
6045  *
6046  * This function will sleep at least once waiting for new free space to
6047  * show up, and then it will check the block group free space numbers
6048  * for our min num_bytes.  Another option is to have it go ahead
6049  * and look in the rbtree for a free extent of a given size, but this
6050  * is a good start.
6051  *
6052  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6053  * any of the information in this block group.
6054  */
6055 static noinline void
6056 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6057                                 u64 num_bytes)
6058 {
6059         struct btrfs_caching_control *caching_ctl;
6060
6061         caching_ctl = get_caching_control(cache);
6062         if (!caching_ctl)
6063                 return;
6064
6065         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6066                    (cache->free_space_ctl->free_space >= num_bytes));
6067
6068         put_caching_control(caching_ctl);
6069 }
6070
6071 static noinline int
6072 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6073 {
6074         struct btrfs_caching_control *caching_ctl;
6075         int ret = 0;
6076
6077         caching_ctl = get_caching_control(cache);
6078         if (!caching_ctl)
6079                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6080
6081         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6082         if (cache->cached == BTRFS_CACHE_ERROR)
6083                 ret = -EIO;
6084         put_caching_control(caching_ctl);
6085         return ret;
6086 }
6087
6088 int __get_raid_index(u64 flags)
6089 {
6090         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6091                 return BTRFS_RAID_RAID10;
6092         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6093                 return BTRFS_RAID_RAID1;
6094         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6095                 return BTRFS_RAID_DUP;
6096         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6097                 return BTRFS_RAID_RAID0;
6098         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6099                 return BTRFS_RAID_RAID5;
6100         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6101                 return BTRFS_RAID_RAID6;
6102
6103         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6104 }
6105
6106 static int get_block_group_index(struct btrfs_block_group_cache *cache)
6107 {
6108         return __get_raid_index(cache->flags);
6109 }
6110
6111 enum btrfs_loop_type {
6112         LOOP_CACHING_NOWAIT = 0,
6113         LOOP_CACHING_WAIT = 1,
6114         LOOP_ALLOC_CHUNK = 2,
6115         LOOP_NO_EMPTY_SIZE = 3,
6116 };
6117
6118 /*
6119  * walks the btree of allocated extents and find a hole of a given size.
6120  * The key ins is changed to record the hole:
6121  * ins->objectid == start position
6122  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6123  * ins->offset == the size of the hole.
6124  * Any available blocks before search_start are skipped.
6125  *
6126  * If there is no suitable free space, we will record the max size of
6127  * the free space extent currently.
6128  */
6129 static noinline int find_free_extent(struct btrfs_root *orig_root,
6130                                      u64 num_bytes, u64 empty_size,
6131                                      u64 hint_byte, struct btrfs_key *ins,
6132                                      u64 flags)
6133 {
6134         int ret = 0;
6135         struct btrfs_root *root = orig_root->fs_info->extent_root;
6136         struct btrfs_free_cluster *last_ptr = NULL;
6137         struct btrfs_block_group_cache *block_group = NULL;
6138         struct btrfs_block_group_cache *used_block_group;
6139         u64 search_start = 0;
6140         u64 max_extent_size = 0;
6141         int empty_cluster = 2 * 1024 * 1024;
6142         struct btrfs_space_info *space_info;
6143         int loop = 0;
6144         int index = __get_raid_index(flags);
6145         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6146                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6147         bool found_uncached_bg = false;
6148         bool failed_cluster_refill = false;
6149         bool failed_alloc = false;
6150         bool use_cluster = true;
6151         bool have_caching_bg = false;
6152
6153         WARN_ON(num_bytes < root->sectorsize);
6154         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
6155         ins->objectid = 0;
6156         ins->offset = 0;
6157
6158         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6159
6160         space_info = __find_space_info(root->fs_info, flags);
6161         if (!space_info) {
6162                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6163                 return -ENOSPC;
6164         }
6165
6166         /*
6167          * If the space info is for both data and metadata it means we have a
6168          * small filesystem and we can't use the clustering stuff.
6169          */
6170         if (btrfs_mixed_space_info(space_info))
6171                 use_cluster = false;
6172
6173         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6174                 last_ptr = &root->fs_info->meta_alloc_cluster;
6175                 if (!btrfs_test_opt(root, SSD))
6176                         empty_cluster = 64 * 1024;
6177         }
6178
6179         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6180             btrfs_test_opt(root, SSD)) {
6181                 last_ptr = &root->fs_info->data_alloc_cluster;
6182         }
6183
6184         if (last_ptr) {
6185                 spin_lock(&last_ptr->lock);
6186                 if (last_ptr->block_group)
6187                         hint_byte = last_ptr->window_start;
6188                 spin_unlock(&last_ptr->lock);
6189         }
6190
6191         search_start = max(search_start, first_logical_byte(root, 0));
6192         search_start = max(search_start, hint_byte);
6193
6194         if (!last_ptr)
6195                 empty_cluster = 0;
6196
6197         if (search_start == hint_byte) {
6198                 block_group = btrfs_lookup_block_group(root->fs_info,
6199                                                        search_start);
6200                 used_block_group = block_group;
6201                 /*
6202                  * we don't want to use the block group if it doesn't match our
6203                  * allocation bits, or if its not cached.
6204                  *
6205                  * However if we are re-searching with an ideal block group
6206                  * picked out then we don't care that the block group is cached.
6207                  */
6208                 if (block_group && block_group_bits(block_group, flags) &&
6209                     block_group->cached != BTRFS_CACHE_NO) {
6210                         down_read(&space_info->groups_sem);
6211                         if (list_empty(&block_group->list) ||
6212                             block_group->ro) {
6213                                 /*
6214                                  * someone is removing this block group,
6215                                  * we can't jump into the have_block_group
6216                                  * target because our list pointers are not
6217                                  * valid
6218                                  */
6219                                 btrfs_put_block_group(block_group);
6220                                 up_read(&space_info->groups_sem);
6221                         } else {
6222                                 index = get_block_group_index(block_group);
6223                                 goto have_block_group;
6224                         }
6225                 } else if (block_group) {
6226                         btrfs_put_block_group(block_group);
6227                 }
6228         }
6229 search:
6230         have_caching_bg = false;
6231         down_read(&space_info->groups_sem);
6232         list_for_each_entry(block_group, &space_info->block_groups[index],
6233                             list) {
6234                 u64 offset;
6235                 int cached;
6236
6237                 used_block_group = block_group;
6238                 btrfs_get_block_group(block_group);
6239                 search_start = block_group->key.objectid;
6240
6241                 /*
6242                  * this can happen if we end up cycling through all the
6243                  * raid types, but we want to make sure we only allocate
6244                  * for the proper type.
6245                  */
6246                 if (!block_group_bits(block_group, flags)) {
6247                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6248                                 BTRFS_BLOCK_GROUP_RAID1 |
6249                                 BTRFS_BLOCK_GROUP_RAID5 |
6250                                 BTRFS_BLOCK_GROUP_RAID6 |
6251                                 BTRFS_BLOCK_GROUP_RAID10;
6252
6253                         /*
6254                          * if they asked for extra copies and this block group
6255                          * doesn't provide them, bail.  This does allow us to
6256                          * fill raid0 from raid1.
6257                          */
6258                         if ((flags & extra) && !(block_group->flags & extra))
6259                                 goto loop;
6260                 }
6261
6262 have_block_group:
6263                 cached = block_group_cache_done(block_group);
6264                 if (unlikely(!cached)) {
6265                         found_uncached_bg = true;
6266                         ret = cache_block_group(block_group, 0);
6267                         BUG_ON(ret < 0);
6268                         ret = 0;
6269                 }
6270
6271                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6272                         goto loop;
6273                 if (unlikely(block_group->ro))
6274                         goto loop;
6275
6276                 /*
6277                  * Ok we want to try and use the cluster allocator, so
6278                  * lets look there
6279                  */
6280                 if (last_ptr) {
6281                         unsigned long aligned_cluster;
6282                         /*
6283                          * the refill lock keeps out other
6284                          * people trying to start a new cluster
6285                          */
6286                         spin_lock(&last_ptr->refill_lock);
6287                         used_block_group = last_ptr->block_group;
6288                         if (used_block_group != block_group &&
6289                             (!used_block_group ||
6290                              used_block_group->ro ||
6291                              !block_group_bits(used_block_group, flags))) {
6292                                 used_block_group = block_group;
6293                                 goto refill_cluster;
6294                         }
6295
6296                         if (used_block_group != block_group)
6297                                 btrfs_get_block_group(used_block_group);
6298
6299                         offset = btrfs_alloc_from_cluster(used_block_group,
6300                                                 last_ptr,
6301                                                 num_bytes,
6302                                                 used_block_group->key.objectid,
6303                                                 &max_extent_size);
6304                         if (offset) {
6305                                 /* we have a block, we're done */
6306                                 spin_unlock(&last_ptr->refill_lock);
6307                                 trace_btrfs_reserve_extent_cluster(root,
6308                                         block_group, search_start, num_bytes);
6309                                 goto checks;
6310                         }
6311
6312                         WARN_ON(last_ptr->block_group != used_block_group);
6313                         if (used_block_group != block_group) {
6314                                 btrfs_put_block_group(used_block_group);
6315                                 used_block_group = block_group;
6316                         }
6317 refill_cluster:
6318                         BUG_ON(used_block_group != block_group);
6319                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6320                          * set up a new clusters, so lets just skip it
6321                          * and let the allocator find whatever block
6322                          * it can find.  If we reach this point, we
6323                          * will have tried the cluster allocator
6324                          * plenty of times and not have found
6325                          * anything, so we are likely way too
6326                          * fragmented for the clustering stuff to find
6327                          * anything.
6328                          *
6329                          * However, if the cluster is taken from the
6330                          * current block group, release the cluster
6331                          * first, so that we stand a better chance of
6332                          * succeeding in the unclustered
6333                          * allocation.  */
6334                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6335                             last_ptr->block_group != block_group) {
6336                                 spin_unlock(&last_ptr->refill_lock);
6337                                 goto unclustered_alloc;
6338                         }
6339
6340                         /*
6341                          * this cluster didn't work out, free it and
6342                          * start over
6343                          */
6344                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6345
6346                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6347                                 spin_unlock(&last_ptr->refill_lock);
6348                                 goto unclustered_alloc;
6349                         }
6350
6351                         aligned_cluster = max_t(unsigned long,
6352                                                 empty_cluster + empty_size,
6353                                               block_group->full_stripe_len);
6354
6355                         /* allocate a cluster in this block group */
6356                         ret = btrfs_find_space_cluster(root, block_group,
6357                                                        last_ptr, search_start,
6358                                                        num_bytes,
6359                                                        aligned_cluster);
6360                         if (ret == 0) {
6361                                 /*
6362                                  * now pull our allocation out of this
6363                                  * cluster
6364                                  */
6365                                 offset = btrfs_alloc_from_cluster(block_group,
6366                                                         last_ptr,
6367                                                         num_bytes,
6368                                                         search_start,
6369                                                         &max_extent_size);
6370                                 if (offset) {
6371                                         /* we found one, proceed */
6372                                         spin_unlock(&last_ptr->refill_lock);
6373                                         trace_btrfs_reserve_extent_cluster(root,
6374                                                 block_group, search_start,
6375                                                 num_bytes);
6376                                         goto checks;
6377                                 }
6378                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6379                                    && !failed_cluster_refill) {
6380                                 spin_unlock(&last_ptr->refill_lock);
6381
6382                                 failed_cluster_refill = true;
6383                                 wait_block_group_cache_progress(block_group,
6384                                        num_bytes + empty_cluster + empty_size);
6385                                 goto have_block_group;
6386                         }
6387
6388                         /*
6389                          * at this point we either didn't find a cluster
6390                          * or we weren't able to allocate a block from our
6391                          * cluster.  Free the cluster we've been trying
6392                          * to use, and go to the next block group
6393                          */
6394                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6395                         spin_unlock(&last_ptr->refill_lock);
6396                         goto loop;
6397                 }
6398
6399 unclustered_alloc:
6400                 spin_lock(&block_group->free_space_ctl->tree_lock);
6401                 if (cached &&
6402                     block_group->free_space_ctl->free_space <
6403                     num_bytes + empty_cluster + empty_size) {
6404                         if (block_group->free_space_ctl->free_space >
6405                             max_extent_size)
6406                                 max_extent_size =
6407                                         block_group->free_space_ctl->free_space;
6408                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6409                         goto loop;
6410                 }
6411                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6412
6413                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6414                                                     num_bytes, empty_size,
6415                                                     &max_extent_size);
6416                 /*
6417                  * If we didn't find a chunk, and we haven't failed on this
6418                  * block group before, and this block group is in the middle of
6419                  * caching and we are ok with waiting, then go ahead and wait
6420                  * for progress to be made, and set failed_alloc to true.
6421                  *
6422                  * If failed_alloc is true then we've already waited on this
6423                  * block group once and should move on to the next block group.
6424                  */
6425                 if (!offset && !failed_alloc && !cached &&
6426                     loop > LOOP_CACHING_NOWAIT) {
6427                         wait_block_group_cache_progress(block_group,
6428                                                 num_bytes + empty_size);
6429                         failed_alloc = true;
6430                         goto have_block_group;
6431                 } else if (!offset) {
6432                         if (!cached)
6433                                 have_caching_bg = true;
6434                         goto loop;
6435                 }
6436 checks:
6437                 search_start = stripe_align(root, used_block_group,
6438                                             offset, num_bytes);
6439
6440                 /* move on to the next group */
6441                 if (search_start + num_bytes >
6442                     used_block_group->key.objectid + used_block_group->key.offset) {
6443                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6444                         goto loop;
6445                 }
6446
6447                 if (offset < search_start)
6448                         btrfs_add_free_space(used_block_group, offset,
6449                                              search_start - offset);
6450                 BUG_ON(offset > search_start);
6451
6452                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
6453                                                   alloc_type);
6454                 if (ret == -EAGAIN) {
6455                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6456                         goto loop;
6457                 }
6458
6459                 /* we are all good, lets return */
6460                 ins->objectid = search_start;
6461                 ins->offset = num_bytes;
6462
6463                 trace_btrfs_reserve_extent(orig_root, block_group,
6464                                            search_start, num_bytes);
6465                 if (used_block_group != block_group)
6466                         btrfs_put_block_group(used_block_group);
6467                 btrfs_put_block_group(block_group);
6468                 break;
6469 loop:
6470                 failed_cluster_refill = false;
6471                 failed_alloc = false;
6472                 BUG_ON(index != get_block_group_index(block_group));
6473                 if (used_block_group != block_group)
6474                         btrfs_put_block_group(used_block_group);
6475                 btrfs_put_block_group(block_group);
6476         }
6477         up_read(&space_info->groups_sem);
6478
6479         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6480                 goto search;
6481
6482         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6483                 goto search;
6484
6485         /*
6486          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6487          *                      caching kthreads as we move along
6488          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6489          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6490          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6491          *                      again
6492          */
6493         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6494                 index = 0;
6495                 loop++;
6496                 if (loop == LOOP_ALLOC_CHUNK) {
6497                         struct btrfs_trans_handle *trans;
6498
6499                         trans = btrfs_join_transaction(root);
6500                         if (IS_ERR(trans)) {
6501                                 ret = PTR_ERR(trans);
6502                                 goto out;
6503                         }
6504
6505                         ret = do_chunk_alloc(trans, root, flags,
6506                                              CHUNK_ALLOC_FORCE);
6507                         /*
6508                          * Do not bail out on ENOSPC since we
6509                          * can do more things.
6510                          */
6511                         if (ret < 0 && ret != -ENOSPC)
6512                                 btrfs_abort_transaction(trans,
6513                                                         root, ret);
6514                         else
6515                                 ret = 0;
6516                         btrfs_end_transaction(trans, root);
6517                         if (ret)
6518                                 goto out;
6519                 }
6520
6521                 if (loop == LOOP_NO_EMPTY_SIZE) {
6522                         empty_size = 0;
6523                         empty_cluster = 0;
6524                 }
6525
6526                 goto search;
6527         } else if (!ins->objectid) {
6528                 ret = -ENOSPC;
6529         } else if (ins->objectid) {
6530                 ret = 0;
6531         }
6532 out:
6533         if (ret == -ENOSPC)
6534                 ins->offset = max_extent_size;
6535         return ret;
6536 }
6537
6538 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6539                             int dump_block_groups)
6540 {
6541         struct btrfs_block_group_cache *cache;
6542         int index = 0;
6543
6544         spin_lock(&info->lock);
6545         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
6546                info->flags,
6547                info->total_bytes - info->bytes_used - info->bytes_pinned -
6548                info->bytes_reserved - info->bytes_readonly,
6549                (info->full) ? "" : "not ");
6550         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
6551                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6552                info->total_bytes, info->bytes_used, info->bytes_pinned,
6553                info->bytes_reserved, info->bytes_may_use,
6554                info->bytes_readonly);
6555         spin_unlock(&info->lock);
6556
6557         if (!dump_block_groups)
6558                 return;
6559
6560         down_read(&info->groups_sem);
6561 again:
6562         list_for_each_entry(cache, &info->block_groups[index], list) {
6563                 spin_lock(&cache->lock);
6564                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
6565                        cache->key.objectid, cache->key.offset,
6566                        btrfs_block_group_used(&cache->item), cache->pinned,
6567                        cache->reserved, cache->ro ? "[readonly]" : "");
6568                 btrfs_dump_free_space(cache, bytes);
6569                 spin_unlock(&cache->lock);
6570         }
6571         if (++index < BTRFS_NR_RAID_TYPES)
6572                 goto again;
6573         up_read(&info->groups_sem);
6574 }
6575
6576 int btrfs_reserve_extent(struct btrfs_root *root,
6577                          u64 num_bytes, u64 min_alloc_size,
6578                          u64 empty_size, u64 hint_byte,
6579                          struct btrfs_key *ins, int is_data)
6580 {
6581         bool final_tried = false;
6582         u64 flags;
6583         int ret;
6584
6585         flags = btrfs_get_alloc_profile(root, is_data);
6586 again:
6587         WARN_ON(num_bytes < root->sectorsize);
6588         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
6589                                flags);
6590
6591         if (ret == -ENOSPC) {
6592                 if (!final_tried && ins->offset) {
6593                         num_bytes = min(num_bytes >> 1, ins->offset);
6594                         num_bytes = round_down(num_bytes, root->sectorsize);
6595                         num_bytes = max(num_bytes, min_alloc_size);
6596                         if (num_bytes == min_alloc_size)
6597                                 final_tried = true;
6598                         goto again;
6599                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6600                         struct btrfs_space_info *sinfo;
6601
6602                         sinfo = __find_space_info(root->fs_info, flags);
6603                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6604                                 flags, num_bytes);
6605                         if (sinfo)
6606                                 dump_space_info(sinfo, num_bytes, 1);
6607                 }
6608         }
6609
6610         return ret;
6611 }
6612
6613 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6614                                         u64 start, u64 len, int pin)
6615 {
6616         struct btrfs_block_group_cache *cache;
6617         int ret = 0;
6618
6619         cache = btrfs_lookup_block_group(root->fs_info, start);
6620         if (!cache) {
6621                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6622                         start);
6623                 return -ENOSPC;
6624         }
6625
6626         if (btrfs_test_opt(root, DISCARD))
6627                 ret = btrfs_discard_extent(root, start, len, NULL);
6628
6629         if (pin)
6630                 pin_down_extent(root, cache, start, len, 1);
6631         else {
6632                 btrfs_add_free_space(cache, start, len);
6633                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6634         }
6635         btrfs_put_block_group(cache);
6636
6637         trace_btrfs_reserved_extent_free(root, start, len);
6638
6639         return ret;
6640 }
6641
6642 int btrfs_free_reserved_extent(struct btrfs_root *root,
6643                                         u64 start, u64 len)
6644 {
6645         return __btrfs_free_reserved_extent(root, start, len, 0);
6646 }
6647
6648 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6649                                        u64 start, u64 len)
6650 {
6651         return __btrfs_free_reserved_extent(root, start, len, 1);
6652 }
6653
6654 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6655                                       struct btrfs_root *root,
6656                                       u64 parent, u64 root_objectid,
6657                                       u64 flags, u64 owner, u64 offset,
6658                                       struct btrfs_key *ins, int ref_mod)
6659 {
6660         int ret;
6661         struct btrfs_fs_info *fs_info = root->fs_info;
6662         struct btrfs_extent_item *extent_item;
6663         struct btrfs_extent_inline_ref *iref;
6664         struct btrfs_path *path;
6665         struct extent_buffer *leaf;
6666         int type;
6667         u32 size;
6668
6669         if (parent > 0)
6670                 type = BTRFS_SHARED_DATA_REF_KEY;
6671         else
6672                 type = BTRFS_EXTENT_DATA_REF_KEY;
6673
6674         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6675
6676         path = btrfs_alloc_path();
6677         if (!path)
6678                 return -ENOMEM;
6679
6680         path->leave_spinning = 1;
6681         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6682                                       ins, size);
6683         if (ret) {
6684                 btrfs_free_path(path);
6685                 return ret;
6686         }
6687
6688         leaf = path->nodes[0];
6689         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6690                                      struct btrfs_extent_item);
6691         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6692         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6693         btrfs_set_extent_flags(leaf, extent_item,
6694                                flags | BTRFS_EXTENT_FLAG_DATA);
6695
6696         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6697         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6698         if (parent > 0) {
6699                 struct btrfs_shared_data_ref *ref;
6700                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6701                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6702                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6703         } else {
6704                 struct btrfs_extent_data_ref *ref;
6705                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6706                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6707                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6708                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6709                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6710         }
6711
6712         btrfs_mark_buffer_dirty(path->nodes[0]);
6713         btrfs_free_path(path);
6714
6715         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6716         if (ret) { /* -ENOENT, logic error */
6717                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6718                         ins->objectid, ins->offset);
6719                 BUG();
6720         }
6721         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
6722         return ret;
6723 }
6724
6725 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6726                                      struct btrfs_root *root,
6727                                      u64 parent, u64 root_objectid,
6728                                      u64 flags, struct btrfs_disk_key *key,
6729                                      int level, struct btrfs_key *ins)
6730 {
6731         int ret;
6732         struct btrfs_fs_info *fs_info = root->fs_info;
6733         struct btrfs_extent_item *extent_item;
6734         struct btrfs_tree_block_info *block_info;
6735         struct btrfs_extent_inline_ref *iref;
6736         struct btrfs_path *path;
6737         struct extent_buffer *leaf;
6738         u32 size = sizeof(*extent_item) + sizeof(*iref);
6739         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6740                                                  SKINNY_METADATA);
6741
6742         if (!skinny_metadata)
6743                 size += sizeof(*block_info);
6744
6745         path = btrfs_alloc_path();
6746         if (!path) {
6747                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
6748                                                    root->leafsize);
6749                 return -ENOMEM;
6750         }
6751
6752         path->leave_spinning = 1;
6753         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6754                                       ins, size);
6755         if (ret) {
6756                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
6757                                                    root->leafsize);
6758                 btrfs_free_path(path);
6759                 return ret;
6760         }
6761
6762         leaf = path->nodes[0];
6763         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6764                                      struct btrfs_extent_item);
6765         btrfs_set_extent_refs(leaf, extent_item, 1);
6766         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6767         btrfs_set_extent_flags(leaf, extent_item,
6768                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6769
6770         if (skinny_metadata) {
6771                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6772         } else {
6773                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6774                 btrfs_set_tree_block_key(leaf, block_info, key);
6775                 btrfs_set_tree_block_level(leaf, block_info, level);
6776                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6777         }
6778
6779         if (parent > 0) {
6780                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6781                 btrfs_set_extent_inline_ref_type(leaf, iref,
6782                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6783                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6784         } else {
6785                 btrfs_set_extent_inline_ref_type(leaf, iref,
6786                                                  BTRFS_TREE_BLOCK_REF_KEY);
6787                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6788         }
6789
6790         btrfs_mark_buffer_dirty(leaf);
6791         btrfs_free_path(path);
6792
6793         ret = update_block_group(root, ins->objectid, root->leafsize, 1);
6794         if (ret) { /* -ENOENT, logic error */
6795                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6796                         ins->objectid, ins->offset);
6797                 BUG();
6798         }
6799
6800         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->leafsize);
6801         return ret;
6802 }
6803
6804 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6805                                      struct btrfs_root *root,
6806                                      u64 root_objectid, u64 owner,
6807                                      u64 offset, struct btrfs_key *ins)
6808 {
6809         int ret;
6810
6811         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6812
6813         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6814                                          ins->offset, 0,
6815                                          root_objectid, owner, offset,
6816                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6817         return ret;
6818 }
6819
6820 /*
6821  * this is used by the tree logging recovery code.  It records that
6822  * an extent has been allocated and makes sure to clear the free
6823  * space cache bits as well
6824  */
6825 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6826                                    struct btrfs_root *root,
6827                                    u64 root_objectid, u64 owner, u64 offset,
6828                                    struct btrfs_key *ins)
6829 {
6830         int ret;
6831         struct btrfs_block_group_cache *block_group;
6832
6833         /*
6834          * Mixed block groups will exclude before processing the log so we only
6835          * need to do the exlude dance if this fs isn't mixed.
6836          */
6837         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
6838                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
6839                 if (ret)
6840                         return ret;
6841         }
6842
6843         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6844         if (!block_group)
6845                 return -EINVAL;
6846
6847         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6848                                           RESERVE_ALLOC_NO_ACCOUNT);
6849         BUG_ON(ret); /* logic error */
6850         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6851                                          0, owner, offset, ins, 1);
6852         btrfs_put_block_group(block_group);
6853         return ret;
6854 }
6855
6856 static struct extent_buffer *
6857 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6858                       u64 bytenr, u32 blocksize, int level)
6859 {
6860         struct extent_buffer *buf;
6861
6862         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6863         if (!buf)
6864                 return ERR_PTR(-ENOMEM);
6865         btrfs_set_header_generation(buf, trans->transid);
6866         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6867         btrfs_tree_lock(buf);
6868         clean_tree_block(trans, root, buf);
6869         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6870
6871         btrfs_set_lock_blocking(buf);
6872         btrfs_set_buffer_uptodate(buf);
6873
6874         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6875                 /*
6876                  * we allow two log transactions at a time, use different
6877                  * EXENT bit to differentiate dirty pages.
6878                  */
6879                 if (root->log_transid % 2 == 0)
6880                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6881                                         buf->start + buf->len - 1, GFP_NOFS);
6882                 else
6883                         set_extent_new(&root->dirty_log_pages, buf->start,
6884                                         buf->start + buf->len - 1, GFP_NOFS);
6885         } else {
6886                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6887                          buf->start + buf->len - 1, GFP_NOFS);
6888         }
6889         trans->blocks_used++;
6890         /* this returns a buffer locked for blocking */
6891         return buf;
6892 }
6893
6894 static struct btrfs_block_rsv *
6895 use_block_rsv(struct btrfs_trans_handle *trans,
6896               struct btrfs_root *root, u32 blocksize)
6897 {
6898         struct btrfs_block_rsv *block_rsv;
6899         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6900         int ret;
6901         bool global_updated = false;
6902
6903         block_rsv = get_block_rsv(trans, root);
6904
6905         if (unlikely(block_rsv->size == 0))
6906                 goto try_reserve;
6907 again:
6908         ret = block_rsv_use_bytes(block_rsv, blocksize);
6909         if (!ret)
6910                 return block_rsv;
6911
6912         if (block_rsv->failfast)
6913                 return ERR_PTR(ret);
6914
6915         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
6916                 global_updated = true;
6917                 update_global_block_rsv(root->fs_info);
6918                 goto again;
6919         }
6920
6921         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6922                 static DEFINE_RATELIMIT_STATE(_rs,
6923                                 DEFAULT_RATELIMIT_INTERVAL * 10,
6924                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
6925                 if (__ratelimit(&_rs))
6926                         WARN(1, KERN_DEBUG
6927                                 "btrfs: block rsv returned %d\n", ret);
6928         }
6929 try_reserve:
6930         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
6931                                      BTRFS_RESERVE_NO_FLUSH);
6932         if (!ret)
6933                 return block_rsv;
6934         /*
6935          * If we couldn't reserve metadata bytes try and use some from
6936          * the global reserve if its space type is the same as the global
6937          * reservation.
6938          */
6939         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
6940             block_rsv->space_info == global_rsv->space_info) {
6941                 ret = block_rsv_use_bytes(global_rsv, blocksize);
6942                 if (!ret)
6943                         return global_rsv;
6944         }
6945         return ERR_PTR(ret);
6946 }
6947
6948 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6949                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6950 {
6951         block_rsv_add_bytes(block_rsv, blocksize, 0);
6952         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6953 }
6954
6955 /*
6956  * finds a free extent and does all the dirty work required for allocation
6957  * returns the key for the extent through ins, and a tree buffer for
6958  * the first block of the extent through buf.
6959  *
6960  * returns the tree buffer or NULL.
6961  */
6962 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6963                                         struct btrfs_root *root, u32 blocksize,
6964                                         u64 parent, u64 root_objectid,
6965                                         struct btrfs_disk_key *key, int level,
6966                                         u64 hint, u64 empty_size)
6967 {
6968         struct btrfs_key ins;
6969         struct btrfs_block_rsv *block_rsv;
6970         struct extent_buffer *buf;
6971         u64 flags = 0;
6972         int ret;
6973         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6974                                                  SKINNY_METADATA);
6975
6976         block_rsv = use_block_rsv(trans, root, blocksize);
6977         if (IS_ERR(block_rsv))
6978                 return ERR_CAST(block_rsv);
6979
6980         ret = btrfs_reserve_extent(root, blocksize, blocksize,
6981                                    empty_size, hint, &ins, 0);
6982         if (ret) {
6983                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6984                 return ERR_PTR(ret);
6985         }
6986
6987         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6988                                     blocksize, level);
6989         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6990
6991         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6992                 if (parent == 0)
6993                         parent = ins.objectid;
6994                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6995         } else
6996                 BUG_ON(parent > 0);
6997
6998         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6999                 struct btrfs_delayed_extent_op *extent_op;
7000                 extent_op = btrfs_alloc_delayed_extent_op();
7001                 BUG_ON(!extent_op); /* -ENOMEM */
7002                 if (key)
7003                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
7004                 else
7005                         memset(&extent_op->key, 0, sizeof(extent_op->key));
7006                 extent_op->flags_to_set = flags;
7007                 if (skinny_metadata)
7008                         extent_op->update_key = 0;
7009                 else
7010                         extent_op->update_key = 1;
7011                 extent_op->update_flags = 1;
7012                 extent_op->is_data = 0;
7013                 extent_op->level = level;
7014
7015                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7016                                         ins.objectid,
7017                                         ins.offset, parent, root_objectid,
7018                                         level, BTRFS_ADD_DELAYED_EXTENT,
7019                                         extent_op, 0);
7020                 BUG_ON(ret); /* -ENOMEM */
7021         }
7022         return buf;
7023 }
7024
7025 struct walk_control {
7026         u64 refs[BTRFS_MAX_LEVEL];
7027         u64 flags[BTRFS_MAX_LEVEL];
7028         struct btrfs_key update_progress;
7029         int stage;
7030         int level;
7031         int shared_level;
7032         int update_ref;
7033         int keep_locks;
7034         int reada_slot;
7035         int reada_count;
7036         int for_reloc;
7037 };
7038
7039 #define DROP_REFERENCE  1
7040 #define UPDATE_BACKREF  2
7041
7042 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7043                                      struct btrfs_root *root,
7044                                      struct walk_control *wc,
7045                                      struct btrfs_path *path)
7046 {
7047         u64 bytenr;
7048         u64 generation;
7049         u64 refs;
7050         u64 flags;
7051         u32 nritems;
7052         u32 blocksize;
7053         struct btrfs_key key;
7054         struct extent_buffer *eb;
7055         int ret;
7056         int slot;
7057         int nread = 0;
7058
7059         if (path->slots[wc->level] < wc->reada_slot) {
7060                 wc->reada_count = wc->reada_count * 2 / 3;
7061                 wc->reada_count = max(wc->reada_count, 2);
7062         } else {
7063                 wc->reada_count = wc->reada_count * 3 / 2;
7064                 wc->reada_count = min_t(int, wc->reada_count,
7065                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7066         }
7067
7068         eb = path->nodes[wc->level];
7069         nritems = btrfs_header_nritems(eb);
7070         blocksize = btrfs_level_size(root, wc->level - 1);
7071
7072         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7073                 if (nread >= wc->reada_count)
7074                         break;
7075
7076                 cond_resched();
7077                 bytenr = btrfs_node_blockptr(eb, slot);
7078                 generation = btrfs_node_ptr_generation(eb, slot);
7079
7080                 if (slot == path->slots[wc->level])
7081                         goto reada;
7082
7083                 if (wc->stage == UPDATE_BACKREF &&
7084                     generation <= root->root_key.offset)
7085                         continue;
7086
7087                 /* We don't lock the tree block, it's OK to be racy here */
7088                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7089                                                wc->level - 1, 1, &refs,
7090                                                &flags);
7091                 /* We don't care about errors in readahead. */
7092                 if (ret < 0)
7093                         continue;
7094                 BUG_ON(refs == 0);
7095
7096                 if (wc->stage == DROP_REFERENCE) {
7097                         if (refs == 1)
7098                                 goto reada;
7099
7100                         if (wc->level == 1 &&
7101                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7102                                 continue;
7103                         if (!wc->update_ref ||
7104                             generation <= root->root_key.offset)
7105                                 continue;
7106                         btrfs_node_key_to_cpu(eb, &key, slot);
7107                         ret = btrfs_comp_cpu_keys(&key,
7108                                                   &wc->update_progress);
7109                         if (ret < 0)
7110                                 continue;
7111                 } else {
7112                         if (wc->level == 1 &&
7113                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7114                                 continue;
7115                 }
7116 reada:
7117                 ret = readahead_tree_block(root, bytenr, blocksize,
7118                                            generation);
7119                 if (ret)
7120                         break;
7121                 nread++;
7122         }
7123         wc->reada_slot = slot;
7124 }
7125
7126 /*
7127  * helper to process tree block while walking down the tree.
7128  *
7129  * when wc->stage == UPDATE_BACKREF, this function updates
7130  * back refs for pointers in the block.
7131  *
7132  * NOTE: return value 1 means we should stop walking down.
7133  */
7134 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7135                                    struct btrfs_root *root,
7136                                    struct btrfs_path *path,
7137                                    struct walk_control *wc, int lookup_info)
7138 {
7139         int level = wc->level;
7140         struct extent_buffer *eb = path->nodes[level];
7141         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7142         int ret;
7143
7144         if (wc->stage == UPDATE_BACKREF &&
7145             btrfs_header_owner(eb) != root->root_key.objectid)
7146                 return 1;
7147
7148         /*
7149          * when reference count of tree block is 1, it won't increase
7150          * again. once full backref flag is set, we never clear it.
7151          */
7152         if (lookup_info &&
7153             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7154              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7155                 BUG_ON(!path->locks[level]);
7156                 ret = btrfs_lookup_extent_info(trans, root,
7157                                                eb->start, level, 1,
7158                                                &wc->refs[level],
7159                                                &wc->flags[level]);
7160                 BUG_ON(ret == -ENOMEM);
7161                 if (ret)
7162                         return ret;
7163                 BUG_ON(wc->refs[level] == 0);
7164         }
7165
7166         if (wc->stage == DROP_REFERENCE) {
7167                 if (wc->refs[level] > 1)
7168                         return 1;
7169
7170                 if (path->locks[level] && !wc->keep_locks) {
7171                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7172                         path->locks[level] = 0;
7173                 }
7174                 return 0;
7175         }
7176
7177         /* wc->stage == UPDATE_BACKREF */
7178         if (!(wc->flags[level] & flag)) {
7179                 BUG_ON(!path->locks[level]);
7180                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
7181                 BUG_ON(ret); /* -ENOMEM */
7182                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
7183                 BUG_ON(ret); /* -ENOMEM */
7184                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7185                                                   eb->len, flag,
7186                                                   btrfs_header_level(eb), 0);
7187                 BUG_ON(ret); /* -ENOMEM */
7188                 wc->flags[level] |= flag;
7189         }
7190
7191         /*
7192          * the block is shared by multiple trees, so it's not good to
7193          * keep the tree lock
7194          */
7195         if (path->locks[level] && level > 0) {
7196                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7197                 path->locks[level] = 0;
7198         }
7199         return 0;
7200 }
7201
7202 /*
7203  * helper to process tree block pointer.
7204  *
7205  * when wc->stage == DROP_REFERENCE, this function checks
7206  * reference count of the block pointed to. if the block
7207  * is shared and we need update back refs for the subtree
7208  * rooted at the block, this function changes wc->stage to
7209  * UPDATE_BACKREF. if the block is shared and there is no
7210  * need to update back, this function drops the reference
7211  * to the block.
7212  *
7213  * NOTE: return value 1 means we should stop walking down.
7214  */
7215 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
7216                                  struct btrfs_root *root,
7217                                  struct btrfs_path *path,
7218                                  struct walk_control *wc, int *lookup_info)
7219 {
7220         u64 bytenr;
7221         u64 generation;
7222         u64 parent;
7223         u32 blocksize;
7224         struct btrfs_key key;
7225         struct extent_buffer *next;
7226         int level = wc->level;
7227         int reada = 0;
7228         int ret = 0;
7229
7230         generation = btrfs_node_ptr_generation(path->nodes[level],
7231                                                path->slots[level]);
7232         /*
7233          * if the lower level block was created before the snapshot
7234          * was created, we know there is no need to update back refs
7235          * for the subtree
7236          */
7237         if (wc->stage == UPDATE_BACKREF &&
7238             generation <= root->root_key.offset) {
7239                 *lookup_info = 1;
7240                 return 1;
7241         }
7242
7243         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7244         blocksize = btrfs_level_size(root, level - 1);
7245
7246         next = btrfs_find_tree_block(root, bytenr, blocksize);
7247         if (!next) {
7248                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
7249                 if (!next)
7250                         return -ENOMEM;
7251                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
7252                                                level - 1);
7253                 reada = 1;
7254         }
7255         btrfs_tree_lock(next);
7256         btrfs_set_lock_blocking(next);
7257
7258         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7259                                        &wc->refs[level - 1],
7260                                        &wc->flags[level - 1]);
7261         if (ret < 0) {
7262                 btrfs_tree_unlock(next);
7263                 return ret;
7264         }
7265
7266         if (unlikely(wc->refs[level - 1] == 0)) {
7267                 btrfs_err(root->fs_info, "Missing references.");
7268                 BUG();
7269         }
7270         *lookup_info = 0;
7271
7272         if (wc->stage == DROP_REFERENCE) {
7273                 if (wc->refs[level - 1] > 1) {
7274                         if (level == 1 &&
7275                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7276                                 goto skip;
7277
7278                         if (!wc->update_ref ||
7279                             generation <= root->root_key.offset)
7280                                 goto skip;
7281
7282                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7283                                               path->slots[level]);
7284                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7285                         if (ret < 0)
7286                                 goto skip;
7287
7288                         wc->stage = UPDATE_BACKREF;
7289                         wc->shared_level = level - 1;
7290                 }
7291         } else {
7292                 if (level == 1 &&
7293                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7294                         goto skip;
7295         }
7296
7297         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7298                 btrfs_tree_unlock(next);
7299                 free_extent_buffer(next);
7300                 next = NULL;
7301                 *lookup_info = 1;
7302         }
7303
7304         if (!next) {
7305                 if (reada && level == 1)
7306                         reada_walk_down(trans, root, wc, path);
7307                 next = read_tree_block(root, bytenr, blocksize, generation);
7308                 if (!next || !extent_buffer_uptodate(next)) {
7309                         free_extent_buffer(next);
7310                         return -EIO;
7311                 }
7312                 btrfs_tree_lock(next);
7313                 btrfs_set_lock_blocking(next);
7314         }
7315
7316         level--;
7317         BUG_ON(level != btrfs_header_level(next));
7318         path->nodes[level] = next;
7319         path->slots[level] = 0;
7320         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7321         wc->level = level;
7322         if (wc->level == 1)
7323                 wc->reada_slot = 0;
7324         return 0;
7325 skip:
7326         wc->refs[level - 1] = 0;
7327         wc->flags[level - 1] = 0;
7328         if (wc->stage == DROP_REFERENCE) {
7329                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7330                         parent = path->nodes[level]->start;
7331                 } else {
7332                         BUG_ON(root->root_key.objectid !=
7333                                btrfs_header_owner(path->nodes[level]));
7334                         parent = 0;
7335                 }
7336
7337                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7338                                 root->root_key.objectid, level - 1, 0, 0);
7339                 BUG_ON(ret); /* -ENOMEM */
7340         }
7341         btrfs_tree_unlock(next);
7342         free_extent_buffer(next);
7343         *lookup_info = 1;
7344         return 1;
7345 }
7346
7347 /*
7348  * helper to process tree block while walking up the tree.
7349  *
7350  * when wc->stage == DROP_REFERENCE, this function drops
7351  * reference count on the block.
7352  *
7353  * when wc->stage == UPDATE_BACKREF, this function changes
7354  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7355  * to UPDATE_BACKREF previously while processing the block.
7356  *
7357  * NOTE: return value 1 means we should stop walking up.
7358  */
7359 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7360                                  struct btrfs_root *root,
7361                                  struct btrfs_path *path,
7362                                  struct walk_control *wc)
7363 {
7364         int ret;
7365         int level = wc->level;
7366         struct extent_buffer *eb = path->nodes[level];
7367         u64 parent = 0;
7368
7369         if (wc->stage == UPDATE_BACKREF) {
7370                 BUG_ON(wc->shared_level < level);
7371                 if (level < wc->shared_level)
7372                         goto out;
7373
7374                 ret = find_next_key(path, level + 1, &wc->update_progress);
7375                 if (ret > 0)
7376                         wc->update_ref = 0;
7377
7378                 wc->stage = DROP_REFERENCE;
7379                 wc->shared_level = -1;
7380                 path->slots[level] = 0;
7381
7382                 /*
7383                  * check reference count again if the block isn't locked.
7384                  * we should start walking down the tree again if reference
7385                  * count is one.
7386                  */
7387                 if (!path->locks[level]) {
7388                         BUG_ON(level == 0);
7389                         btrfs_tree_lock(eb);
7390                         btrfs_set_lock_blocking(eb);
7391                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7392
7393                         ret = btrfs_lookup_extent_info(trans, root,
7394                                                        eb->start, level, 1,
7395                                                        &wc->refs[level],
7396                                                        &wc->flags[level]);
7397                         if (ret < 0) {
7398                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7399                                 path->locks[level] = 0;
7400                                 return ret;
7401                         }
7402                         BUG_ON(wc->refs[level] == 0);
7403                         if (wc->refs[level] == 1) {
7404                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7405                                 path->locks[level] = 0;
7406                                 return 1;
7407                         }
7408                 }
7409         }
7410
7411         /* wc->stage == DROP_REFERENCE */
7412         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7413
7414         if (wc->refs[level] == 1) {
7415                 if (level == 0) {
7416                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7417                                 ret = btrfs_dec_ref(trans, root, eb, 1,
7418                                                     wc->for_reloc);
7419                         else
7420                                 ret = btrfs_dec_ref(trans, root, eb, 0,
7421                                                     wc->for_reloc);
7422                         BUG_ON(ret); /* -ENOMEM */
7423                 }
7424                 /* make block locked assertion in clean_tree_block happy */
7425                 if (!path->locks[level] &&
7426                     btrfs_header_generation(eb) == trans->transid) {
7427                         btrfs_tree_lock(eb);
7428                         btrfs_set_lock_blocking(eb);
7429                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7430                 }
7431                 clean_tree_block(trans, root, eb);
7432         }
7433
7434         if (eb == root->node) {
7435                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7436                         parent = eb->start;
7437                 else
7438                         BUG_ON(root->root_key.objectid !=
7439                                btrfs_header_owner(eb));
7440         } else {
7441                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7442                         parent = path->nodes[level + 1]->start;
7443                 else
7444                         BUG_ON(root->root_key.objectid !=
7445                                btrfs_header_owner(path->nodes[level + 1]));
7446         }
7447
7448         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7449 out:
7450         wc->refs[level] = 0;
7451         wc->flags[level] = 0;
7452         return 0;
7453 }
7454
7455 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7456                                    struct btrfs_root *root,
7457                                    struct btrfs_path *path,
7458                                    struct walk_control *wc)
7459 {
7460         int level = wc->level;
7461         int lookup_info = 1;
7462         int ret;
7463
7464         while (level >= 0) {
7465                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
7466                 if (ret > 0)
7467                         break;
7468
7469                 if (level == 0)
7470                         break;
7471
7472                 if (path->slots[level] >=
7473                     btrfs_header_nritems(path->nodes[level]))
7474                         break;
7475
7476                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
7477                 if (ret > 0) {
7478                         path->slots[level]++;
7479                         continue;
7480                 } else if (ret < 0)
7481                         return ret;
7482                 level = wc->level;
7483         }
7484         return 0;
7485 }
7486
7487 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
7488                                  struct btrfs_root *root,
7489                                  struct btrfs_path *path,
7490                                  struct walk_control *wc, int max_level)
7491 {
7492         int level = wc->level;
7493         int ret;
7494
7495         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
7496         while (level < max_level && path->nodes[level]) {
7497                 wc->level = level;
7498                 if (path->slots[level] + 1 <
7499                     btrfs_header_nritems(path->nodes[level])) {
7500                         path->slots[level]++;
7501                         return 0;
7502                 } else {
7503                         ret = walk_up_proc(trans, root, path, wc);
7504                         if (ret > 0)
7505                                 return 0;
7506
7507                         if (path->locks[level]) {
7508                                 btrfs_tree_unlock_rw(path->nodes[level],
7509                                                      path->locks[level]);
7510                                 path->locks[level] = 0;
7511                         }
7512                         free_extent_buffer(path->nodes[level]);
7513                         path->nodes[level] = NULL;
7514                         level++;
7515                 }
7516         }
7517         return 1;
7518 }
7519
7520 /*
7521  * drop a subvolume tree.
7522  *
7523  * this function traverses the tree freeing any blocks that only
7524  * referenced by the tree.
7525  *
7526  * when a shared tree block is found. this function decreases its
7527  * reference count by one. if update_ref is true, this function
7528  * also make sure backrefs for the shared block and all lower level
7529  * blocks are properly updated.
7530  *
7531  * If called with for_reloc == 0, may exit early with -EAGAIN
7532  */
7533 int btrfs_drop_snapshot(struct btrfs_root *root,
7534                          struct btrfs_block_rsv *block_rsv, int update_ref,
7535                          int for_reloc)
7536 {
7537         struct btrfs_path *path;
7538         struct btrfs_trans_handle *trans;
7539         struct btrfs_root *tree_root = root->fs_info->tree_root;
7540         struct btrfs_root_item *root_item = &root->root_item;
7541         struct walk_control *wc;
7542         struct btrfs_key key;
7543         int err = 0;
7544         int ret;
7545         int level;
7546         bool root_dropped = false;
7547
7548         path = btrfs_alloc_path();
7549         if (!path) {
7550                 err = -ENOMEM;
7551                 goto out;
7552         }
7553
7554         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7555         if (!wc) {
7556                 btrfs_free_path(path);
7557                 err = -ENOMEM;
7558                 goto out;
7559         }
7560
7561         trans = btrfs_start_transaction(tree_root, 0);
7562         if (IS_ERR(trans)) {
7563                 err = PTR_ERR(trans);
7564                 goto out_free;
7565         }
7566
7567         if (block_rsv)
7568                 trans->block_rsv = block_rsv;
7569
7570         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
7571                 level = btrfs_header_level(root->node);
7572                 path->nodes[level] = btrfs_lock_root_node(root);
7573                 btrfs_set_lock_blocking(path->nodes[level]);
7574                 path->slots[level] = 0;
7575                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7576                 memset(&wc->update_progress, 0,
7577                        sizeof(wc->update_progress));
7578         } else {
7579                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
7580                 memcpy(&wc->update_progress, &key,
7581                        sizeof(wc->update_progress));
7582
7583                 level = root_item->drop_level;
7584                 BUG_ON(level == 0);
7585                 path->lowest_level = level;
7586                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
7587                 path->lowest_level = 0;
7588                 if (ret < 0) {
7589                         err = ret;
7590                         goto out_end_trans;
7591                 }
7592                 WARN_ON(ret > 0);
7593
7594                 /*
7595                  * unlock our path, this is safe because only this
7596                  * function is allowed to delete this snapshot
7597                  */
7598                 btrfs_unlock_up_safe(path, 0);
7599
7600                 level = btrfs_header_level(root->node);
7601                 while (1) {
7602                         btrfs_tree_lock(path->nodes[level]);
7603                         btrfs_set_lock_blocking(path->nodes[level]);
7604                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7605
7606                         ret = btrfs_lookup_extent_info(trans, root,
7607                                                 path->nodes[level]->start,
7608                                                 level, 1, &wc->refs[level],
7609                                                 &wc->flags[level]);
7610                         if (ret < 0) {
7611                                 err = ret;
7612                                 goto out_end_trans;
7613                         }
7614                         BUG_ON(wc->refs[level] == 0);
7615
7616                         if (level == root_item->drop_level)
7617                                 break;
7618
7619                         btrfs_tree_unlock(path->nodes[level]);
7620                         path->locks[level] = 0;
7621                         WARN_ON(wc->refs[level] != 1);
7622                         level--;
7623                 }
7624         }
7625
7626         wc->level = level;
7627         wc->shared_level = -1;
7628         wc->stage = DROP_REFERENCE;
7629         wc->update_ref = update_ref;
7630         wc->keep_locks = 0;
7631         wc->for_reloc = for_reloc;
7632         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7633
7634         while (1) {
7635
7636                 ret = walk_down_tree(trans, root, path, wc);
7637                 if (ret < 0) {
7638                         err = ret;
7639                         break;
7640                 }
7641
7642                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7643                 if (ret < 0) {
7644                         err = ret;
7645                         break;
7646                 }
7647
7648                 if (ret > 0) {
7649                         BUG_ON(wc->stage != DROP_REFERENCE);
7650                         break;
7651                 }
7652
7653                 if (wc->stage == DROP_REFERENCE) {
7654                         level = wc->level;
7655                         btrfs_node_key(path->nodes[level],
7656                                        &root_item->drop_progress,
7657                                        path->slots[level]);
7658                         root_item->drop_level = level;
7659                 }
7660
7661                 BUG_ON(wc->level == 0);
7662                 if (btrfs_should_end_transaction(trans, tree_root) ||
7663                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
7664                         ret = btrfs_update_root(trans, tree_root,
7665                                                 &root->root_key,
7666                                                 root_item);
7667                         if (ret) {
7668                                 btrfs_abort_transaction(trans, tree_root, ret);
7669                                 err = ret;
7670                                 goto out_end_trans;
7671                         }
7672
7673                         btrfs_end_transaction_throttle(trans, tree_root);
7674                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
7675                                 pr_debug("btrfs: drop snapshot early exit\n");
7676                                 err = -EAGAIN;
7677                                 goto out_free;
7678                         }
7679
7680                         trans = btrfs_start_transaction(tree_root, 0);
7681                         if (IS_ERR(trans)) {
7682                                 err = PTR_ERR(trans);
7683                                 goto out_free;
7684                         }
7685                         if (block_rsv)
7686                                 trans->block_rsv = block_rsv;
7687                 }
7688         }
7689         btrfs_release_path(path);
7690         if (err)
7691                 goto out_end_trans;
7692
7693         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7694         if (ret) {
7695                 btrfs_abort_transaction(trans, tree_root, ret);
7696                 goto out_end_trans;
7697         }
7698
7699         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7700                 ret = btrfs_find_root(tree_root, &root->root_key, path,
7701                                       NULL, NULL);
7702                 if (ret < 0) {
7703                         btrfs_abort_transaction(trans, tree_root, ret);
7704                         err = ret;
7705                         goto out_end_trans;
7706                 } else if (ret > 0) {
7707                         /* if we fail to delete the orphan item this time
7708                          * around, it'll get picked up the next time.
7709                          *
7710                          * The most common failure here is just -ENOENT.
7711                          */
7712                         btrfs_del_orphan_item(trans, tree_root,
7713                                               root->root_key.objectid);
7714                 }
7715         }
7716
7717         if (root->in_radix) {
7718                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
7719         } else {
7720                 free_extent_buffer(root->node);
7721                 free_extent_buffer(root->commit_root);
7722                 btrfs_put_fs_root(root);
7723         }
7724         root_dropped = true;
7725 out_end_trans:
7726         btrfs_end_transaction_throttle(trans, tree_root);
7727 out_free:
7728         kfree(wc);
7729         btrfs_free_path(path);
7730 out:
7731         /*
7732          * So if we need to stop dropping the snapshot for whatever reason we
7733          * need to make sure to add it back to the dead root list so that we
7734          * keep trying to do the work later.  This also cleans up roots if we
7735          * don't have it in the radix (like when we recover after a power fail
7736          * or unmount) so we don't leak memory.
7737          */
7738         if (!for_reloc && root_dropped == false)
7739                 btrfs_add_dead_root(root);
7740         if (err)
7741                 btrfs_std_error(root->fs_info, err);
7742         return err;
7743 }
7744
7745 /*
7746  * drop subtree rooted at tree block 'node'.
7747  *
7748  * NOTE: this function will unlock and release tree block 'node'
7749  * only used by relocation code
7750  */
7751 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7752                         struct btrfs_root *root,
7753                         struct extent_buffer *node,
7754                         struct extent_buffer *parent)
7755 {
7756         struct btrfs_path *path;
7757         struct walk_control *wc;
7758         int level;
7759         int parent_level;
7760         int ret = 0;
7761         int wret;
7762
7763         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7764
7765         path = btrfs_alloc_path();
7766         if (!path)
7767                 return -ENOMEM;
7768
7769         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7770         if (!wc) {
7771                 btrfs_free_path(path);
7772                 return -ENOMEM;
7773         }
7774
7775         btrfs_assert_tree_locked(parent);
7776         parent_level = btrfs_header_level(parent);
7777         extent_buffer_get(parent);
7778         path->nodes[parent_level] = parent;
7779         path->slots[parent_level] = btrfs_header_nritems(parent);
7780
7781         btrfs_assert_tree_locked(node);
7782         level = btrfs_header_level(node);
7783         path->nodes[level] = node;
7784         path->slots[level] = 0;
7785         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7786
7787         wc->refs[parent_level] = 1;
7788         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7789         wc->level = level;
7790         wc->shared_level = -1;
7791         wc->stage = DROP_REFERENCE;
7792         wc->update_ref = 0;
7793         wc->keep_locks = 1;
7794         wc->for_reloc = 1;
7795         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7796
7797         while (1) {
7798                 wret = walk_down_tree(trans, root, path, wc);
7799                 if (wret < 0) {
7800                         ret = wret;
7801                         break;
7802                 }
7803
7804                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7805                 if (wret < 0)
7806                         ret = wret;
7807                 if (wret != 0)
7808                         break;
7809         }
7810
7811         kfree(wc);
7812         btrfs_free_path(path);
7813         return ret;
7814 }
7815
7816 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7817 {
7818         u64 num_devices;
7819         u64 stripped;
7820
7821         /*
7822          * if restripe for this chunk_type is on pick target profile and
7823          * return, otherwise do the usual balance
7824          */
7825         stripped = get_restripe_target(root->fs_info, flags);
7826         if (stripped)
7827                 return extended_to_chunk(stripped);
7828
7829         /*
7830          * we add in the count of missing devices because we want
7831          * to make sure that any RAID levels on a degraded FS
7832          * continue to be honored.
7833          */
7834         num_devices = root->fs_info->fs_devices->rw_devices +
7835                 root->fs_info->fs_devices->missing_devices;
7836
7837         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7838                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
7839                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7840
7841         if (num_devices == 1) {
7842                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7843                 stripped = flags & ~stripped;
7844
7845                 /* turn raid0 into single device chunks */
7846                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7847                         return stripped;
7848
7849                 /* turn mirroring into duplication */
7850                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7851                              BTRFS_BLOCK_GROUP_RAID10))
7852                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7853         } else {
7854                 /* they already had raid on here, just return */
7855                 if (flags & stripped)
7856                         return flags;
7857
7858                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7859                 stripped = flags & ~stripped;
7860
7861                 /* switch duplicated blocks with raid1 */
7862                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7863                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7864
7865                 /* this is drive concat, leave it alone */
7866         }
7867
7868         return flags;
7869 }
7870
7871 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7872 {
7873         struct btrfs_space_info *sinfo = cache->space_info;
7874         u64 num_bytes;
7875         u64 min_allocable_bytes;
7876         int ret = -ENOSPC;
7877
7878
7879         /*
7880          * We need some metadata space and system metadata space for
7881          * allocating chunks in some corner cases until we force to set
7882          * it to be readonly.
7883          */
7884         if ((sinfo->flags &
7885              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7886             !force)
7887                 min_allocable_bytes = 1 * 1024 * 1024;
7888         else
7889                 min_allocable_bytes = 0;
7890
7891         spin_lock(&sinfo->lock);
7892         spin_lock(&cache->lock);
7893
7894         if (cache->ro) {
7895                 ret = 0;
7896                 goto out;
7897         }
7898
7899         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7900                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7901
7902         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7903             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7904             min_allocable_bytes <= sinfo->total_bytes) {
7905                 sinfo->bytes_readonly += num_bytes;
7906                 cache->ro = 1;
7907                 ret = 0;
7908         }
7909 out:
7910         spin_unlock(&cache->lock);
7911         spin_unlock(&sinfo->lock);
7912         return ret;
7913 }
7914
7915 int btrfs_set_block_group_ro(struct btrfs_root *root,
7916                              struct btrfs_block_group_cache *cache)
7917
7918 {
7919         struct btrfs_trans_handle *trans;
7920         u64 alloc_flags;
7921         int ret;
7922
7923         BUG_ON(cache->ro);
7924
7925         trans = btrfs_join_transaction(root);
7926         if (IS_ERR(trans))
7927                 return PTR_ERR(trans);
7928
7929         alloc_flags = update_block_group_flags(root, cache->flags);
7930         if (alloc_flags != cache->flags) {
7931                 ret = do_chunk_alloc(trans, root, alloc_flags,
7932                                      CHUNK_ALLOC_FORCE);
7933                 if (ret < 0)
7934                         goto out;
7935         }
7936
7937         ret = set_block_group_ro(cache, 0);
7938         if (!ret)
7939                 goto out;
7940         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7941         ret = do_chunk_alloc(trans, root, alloc_flags,
7942                              CHUNK_ALLOC_FORCE);
7943         if (ret < 0)
7944                 goto out;
7945         ret = set_block_group_ro(cache, 0);
7946 out:
7947         btrfs_end_transaction(trans, root);
7948         return ret;
7949 }
7950
7951 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7952                             struct btrfs_root *root, u64 type)
7953 {
7954         u64 alloc_flags = get_alloc_profile(root, type);
7955         return do_chunk_alloc(trans, root, alloc_flags,
7956                               CHUNK_ALLOC_FORCE);
7957 }
7958
7959 /*
7960  * helper to account the unused space of all the readonly block group in the
7961  * list. takes mirrors into account.
7962  */
7963 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7964 {
7965         struct btrfs_block_group_cache *block_group;
7966         u64 free_bytes = 0;
7967         int factor;
7968
7969         list_for_each_entry(block_group, groups_list, list) {
7970                 spin_lock(&block_group->lock);
7971
7972                 if (!block_group->ro) {
7973                         spin_unlock(&block_group->lock);
7974                         continue;
7975                 }
7976
7977                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7978                                           BTRFS_BLOCK_GROUP_RAID10 |
7979                                           BTRFS_BLOCK_GROUP_DUP))
7980                         factor = 2;
7981                 else
7982                         factor = 1;
7983
7984                 free_bytes += (block_group->key.offset -
7985                                btrfs_block_group_used(&block_group->item)) *
7986                                factor;
7987
7988                 spin_unlock(&block_group->lock);
7989         }
7990
7991         return free_bytes;
7992 }
7993
7994 /*
7995  * helper to account the unused space of all the readonly block group in the
7996  * space_info. takes mirrors into account.
7997  */
7998 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7999 {
8000         int i;
8001         u64 free_bytes = 0;
8002
8003         spin_lock(&sinfo->lock);
8004
8005         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
8006                 if (!list_empty(&sinfo->block_groups[i]))
8007                         free_bytes += __btrfs_get_ro_block_group_free_space(
8008                                                 &sinfo->block_groups[i]);
8009
8010         spin_unlock(&sinfo->lock);
8011
8012         return free_bytes;
8013 }
8014
8015 void btrfs_set_block_group_rw(struct btrfs_root *root,
8016                               struct btrfs_block_group_cache *cache)
8017 {
8018         struct btrfs_space_info *sinfo = cache->space_info;
8019         u64 num_bytes;
8020
8021         BUG_ON(!cache->ro);
8022
8023         spin_lock(&sinfo->lock);
8024         spin_lock(&cache->lock);
8025         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8026                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8027         sinfo->bytes_readonly -= num_bytes;
8028         cache->ro = 0;
8029         spin_unlock(&cache->lock);
8030         spin_unlock(&sinfo->lock);
8031 }
8032
8033 /*
8034  * checks to see if its even possible to relocate this block group.
8035  *
8036  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8037  * ok to go ahead and try.
8038  */
8039 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8040 {
8041         struct btrfs_block_group_cache *block_group;
8042         struct btrfs_space_info *space_info;
8043         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8044         struct btrfs_device *device;
8045         struct btrfs_trans_handle *trans;
8046         u64 min_free;
8047         u64 dev_min = 1;
8048         u64 dev_nr = 0;
8049         u64 target;
8050         int index;
8051         int full = 0;
8052         int ret = 0;
8053
8054         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8055
8056         /* odd, couldn't find the block group, leave it alone */
8057         if (!block_group)
8058                 return -1;
8059
8060         min_free = btrfs_block_group_used(&block_group->item);
8061
8062         /* no bytes used, we're good */
8063         if (!min_free)
8064                 goto out;
8065
8066         space_info = block_group->space_info;
8067         spin_lock(&space_info->lock);
8068
8069         full = space_info->full;
8070
8071         /*
8072          * if this is the last block group we have in this space, we can't
8073          * relocate it unless we're able to allocate a new chunk below.
8074          *
8075          * Otherwise, we need to make sure we have room in the space to handle
8076          * all of the extents from this block group.  If we can, we're good
8077          */
8078         if ((space_info->total_bytes != block_group->key.offset) &&
8079             (space_info->bytes_used + space_info->bytes_reserved +
8080              space_info->bytes_pinned + space_info->bytes_readonly +
8081              min_free < space_info->total_bytes)) {
8082                 spin_unlock(&space_info->lock);
8083                 goto out;
8084         }
8085         spin_unlock(&space_info->lock);
8086
8087         /*
8088          * ok we don't have enough space, but maybe we have free space on our
8089          * devices to allocate new chunks for relocation, so loop through our
8090          * alloc devices and guess if we have enough space.  if this block
8091          * group is going to be restriped, run checks against the target
8092          * profile instead of the current one.
8093          */
8094         ret = -1;
8095
8096         /*
8097          * index:
8098          *      0: raid10
8099          *      1: raid1
8100          *      2: dup
8101          *      3: raid0
8102          *      4: single
8103          */
8104         target = get_restripe_target(root->fs_info, block_group->flags);
8105         if (target) {
8106                 index = __get_raid_index(extended_to_chunk(target));
8107         } else {
8108                 /*
8109                  * this is just a balance, so if we were marked as full
8110                  * we know there is no space for a new chunk
8111                  */
8112                 if (full)
8113                         goto out;
8114
8115                 index = get_block_group_index(block_group);
8116         }
8117
8118         if (index == BTRFS_RAID_RAID10) {
8119                 dev_min = 4;
8120                 /* Divide by 2 */
8121                 min_free >>= 1;
8122         } else if (index == BTRFS_RAID_RAID1) {
8123                 dev_min = 2;
8124         } else if (index == BTRFS_RAID_DUP) {
8125                 /* Multiply by 2 */
8126                 min_free <<= 1;
8127         } else if (index == BTRFS_RAID_RAID0) {
8128                 dev_min = fs_devices->rw_devices;
8129                 do_div(min_free, dev_min);
8130         }
8131
8132         /* We need to do this so that we can look at pending chunks */
8133         trans = btrfs_join_transaction(root);
8134         if (IS_ERR(trans)) {
8135                 ret = PTR_ERR(trans);
8136                 goto out;
8137         }
8138
8139         mutex_lock(&root->fs_info->chunk_mutex);
8140         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8141                 u64 dev_offset;
8142
8143                 /*
8144                  * check to make sure we can actually find a chunk with enough
8145                  * space to fit our block group in.
8146                  */
8147                 if (device->total_bytes > device->bytes_used + min_free &&
8148                     !device->is_tgtdev_for_dev_replace) {
8149                         ret = find_free_dev_extent(trans, device, min_free,
8150                                                    &dev_offset, NULL);
8151                         if (!ret)
8152                                 dev_nr++;
8153
8154                         if (dev_nr >= dev_min)
8155                                 break;
8156
8157                         ret = -1;
8158                 }
8159         }
8160         mutex_unlock(&root->fs_info->chunk_mutex);
8161         btrfs_end_transaction(trans, root);
8162 out:
8163         btrfs_put_block_group(block_group);
8164         return ret;
8165 }
8166
8167 static int find_first_block_group(struct btrfs_root *root,
8168                 struct btrfs_path *path, struct btrfs_key *key)
8169 {
8170         int ret = 0;
8171         struct btrfs_key found_key;
8172         struct extent_buffer *leaf;
8173         int slot;
8174
8175         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
8176         if (ret < 0)
8177                 goto out;
8178
8179         while (1) {
8180                 slot = path->slots[0];
8181                 leaf = path->nodes[0];
8182                 if (slot >= btrfs_header_nritems(leaf)) {
8183                         ret = btrfs_next_leaf(root, path);
8184                         if (ret == 0)
8185                                 continue;
8186                         if (ret < 0)
8187                                 goto out;
8188                         break;
8189                 }
8190                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
8191
8192                 if (found_key.objectid >= key->objectid &&
8193                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
8194                         ret = 0;
8195                         goto out;
8196                 }
8197                 path->slots[0]++;
8198         }
8199 out:
8200         return ret;
8201 }
8202
8203 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
8204 {
8205         struct btrfs_block_group_cache *block_group;
8206         u64 last = 0;
8207
8208         while (1) {
8209                 struct inode *inode;
8210
8211                 block_group = btrfs_lookup_first_block_group(info, last);
8212                 while (block_group) {
8213                         spin_lock(&block_group->lock);
8214                         if (block_group->iref)
8215                                 break;
8216                         spin_unlock(&block_group->lock);
8217                         block_group = next_block_group(info->tree_root,
8218                                                        block_group);
8219                 }
8220                 if (!block_group) {
8221                         if (last == 0)
8222                                 break;
8223                         last = 0;
8224                         continue;
8225                 }
8226
8227                 inode = block_group->inode;
8228                 block_group->iref = 0;
8229                 block_group->inode = NULL;
8230                 spin_unlock(&block_group->lock);
8231                 iput(inode);
8232                 last = block_group->key.objectid + block_group->key.offset;
8233                 btrfs_put_block_group(block_group);
8234         }
8235 }
8236
8237 int btrfs_free_block_groups(struct btrfs_fs_info *info)
8238 {
8239         struct btrfs_block_group_cache *block_group;
8240         struct btrfs_space_info *space_info;
8241         struct btrfs_caching_control *caching_ctl;
8242         struct rb_node *n;
8243
8244         down_write(&info->extent_commit_sem);
8245         while (!list_empty(&info->caching_block_groups)) {
8246                 caching_ctl = list_entry(info->caching_block_groups.next,
8247                                          struct btrfs_caching_control, list);
8248                 list_del(&caching_ctl->list);
8249                 put_caching_control(caching_ctl);
8250         }
8251         up_write(&info->extent_commit_sem);
8252
8253         spin_lock(&info->block_group_cache_lock);
8254         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8255                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8256                                        cache_node);
8257                 rb_erase(&block_group->cache_node,
8258                          &info->block_group_cache_tree);
8259                 spin_unlock(&info->block_group_cache_lock);
8260
8261                 down_write(&block_group->space_info->groups_sem);
8262                 list_del(&block_group->list);
8263                 up_write(&block_group->space_info->groups_sem);
8264
8265                 if (block_group->cached == BTRFS_CACHE_STARTED)
8266                         wait_block_group_cache_done(block_group);
8267
8268                 /*
8269                  * We haven't cached this block group, which means we could
8270                  * possibly have excluded extents on this block group.
8271                  */
8272                 if (block_group->cached == BTRFS_CACHE_NO ||
8273                     block_group->cached == BTRFS_CACHE_ERROR)
8274                         free_excluded_extents(info->extent_root, block_group);
8275
8276                 btrfs_remove_free_space_cache(block_group);
8277                 btrfs_put_block_group(block_group);
8278
8279                 spin_lock(&info->block_group_cache_lock);
8280         }
8281         spin_unlock(&info->block_group_cache_lock);
8282
8283         /* now that all the block groups are freed, go through and
8284          * free all the space_info structs.  This is only called during
8285          * the final stages of unmount, and so we know nobody is
8286          * using them.  We call synchronize_rcu() once before we start,
8287          * just to be on the safe side.
8288          */
8289         synchronize_rcu();
8290
8291         release_global_block_rsv(info);
8292
8293         while(!list_empty(&info->space_info)) {
8294                 space_info = list_entry(info->space_info.next,
8295                                         struct btrfs_space_info,
8296                                         list);
8297                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8298                         if (space_info->bytes_pinned > 0 ||
8299                             space_info->bytes_reserved > 0 ||
8300                             space_info->bytes_may_use > 0) {
8301                                 WARN_ON(1);
8302                                 dump_space_info(space_info, 0, 0);
8303                         }
8304                 }
8305                 percpu_counter_destroy(&space_info->total_bytes_pinned);
8306                 list_del(&space_info->list);
8307                 kfree(space_info);
8308         }
8309         return 0;
8310 }
8311
8312 static void __link_block_group(struct btrfs_space_info *space_info,
8313                                struct btrfs_block_group_cache *cache)
8314 {
8315         int index = get_block_group_index(cache);
8316
8317         down_write(&space_info->groups_sem);
8318         list_add_tail(&cache->list, &space_info->block_groups[index]);
8319         up_write(&space_info->groups_sem);
8320 }
8321
8322 int btrfs_read_block_groups(struct btrfs_root *root)
8323 {
8324         struct btrfs_path *path;
8325         int ret;
8326         struct btrfs_block_group_cache *cache;
8327         struct btrfs_fs_info *info = root->fs_info;
8328         struct btrfs_space_info *space_info;
8329         struct btrfs_key key;
8330         struct btrfs_key found_key;
8331         struct extent_buffer *leaf;
8332         int need_clear = 0;
8333         u64 cache_gen;
8334
8335         root = info->extent_root;
8336         key.objectid = 0;
8337         key.offset = 0;
8338         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
8339         path = btrfs_alloc_path();
8340         if (!path)
8341                 return -ENOMEM;
8342         path->reada = 1;
8343
8344         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
8345         if (btrfs_test_opt(root, SPACE_CACHE) &&
8346             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
8347                 need_clear = 1;
8348         if (btrfs_test_opt(root, CLEAR_CACHE))
8349                 need_clear = 1;
8350
8351         while (1) {
8352                 ret = find_first_block_group(root, path, &key);
8353                 if (ret > 0)
8354                         break;
8355                 if (ret != 0)
8356                         goto error;
8357                 leaf = path->nodes[0];
8358                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8359                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
8360                 if (!cache) {
8361                         ret = -ENOMEM;
8362                         goto error;
8363                 }
8364                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8365                                                 GFP_NOFS);
8366                 if (!cache->free_space_ctl) {
8367                         kfree(cache);
8368                         ret = -ENOMEM;
8369                         goto error;
8370                 }
8371
8372                 atomic_set(&cache->count, 1);
8373                 spin_lock_init(&cache->lock);
8374                 cache->fs_info = info;
8375                 INIT_LIST_HEAD(&cache->list);
8376                 INIT_LIST_HEAD(&cache->cluster_list);
8377
8378                 if (need_clear) {
8379                         /*
8380                          * When we mount with old space cache, we need to
8381                          * set BTRFS_DC_CLEAR and set dirty flag.
8382                          *
8383                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
8384                          *    truncate the old free space cache inode and
8385                          *    setup a new one.
8386                          * b) Setting 'dirty flag' makes sure that we flush
8387                          *    the new space cache info onto disk.
8388                          */
8389                         cache->disk_cache_state = BTRFS_DC_CLEAR;
8390                         if (btrfs_test_opt(root, SPACE_CACHE))
8391                                 cache->dirty = 1;
8392                 }
8393
8394                 read_extent_buffer(leaf, &cache->item,
8395                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
8396                                    sizeof(cache->item));
8397                 memcpy(&cache->key, &found_key, sizeof(found_key));
8398
8399                 key.objectid = found_key.objectid + found_key.offset;
8400                 btrfs_release_path(path);
8401                 cache->flags = btrfs_block_group_flags(&cache->item);
8402                 cache->sectorsize = root->sectorsize;
8403                 cache->full_stripe_len = btrfs_full_stripe_len(root,
8404                                                &root->fs_info->mapping_tree,
8405                                                found_key.objectid);
8406                 btrfs_init_free_space_ctl(cache);
8407
8408                 /*
8409                  * We need to exclude the super stripes now so that the space
8410                  * info has super bytes accounted for, otherwise we'll think
8411                  * we have more space than we actually do.
8412                  */
8413                 ret = exclude_super_stripes(root, cache);
8414                 if (ret) {
8415                         /*
8416                          * We may have excluded something, so call this just in
8417                          * case.
8418                          */
8419                         free_excluded_extents(root, cache);
8420                         kfree(cache->free_space_ctl);
8421                         kfree(cache);
8422                         goto error;
8423                 }
8424
8425                 /*
8426                  * check for two cases, either we are full, and therefore
8427                  * don't need to bother with the caching work since we won't
8428                  * find any space, or we are empty, and we can just add all
8429                  * the space in and be done with it.  This saves us _alot_ of
8430                  * time, particularly in the full case.
8431                  */
8432                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
8433                         cache->last_byte_to_unpin = (u64)-1;
8434                         cache->cached = BTRFS_CACHE_FINISHED;
8435                         free_excluded_extents(root, cache);
8436                 } else if (btrfs_block_group_used(&cache->item) == 0) {
8437                         cache->last_byte_to_unpin = (u64)-1;
8438                         cache->cached = BTRFS_CACHE_FINISHED;
8439                         add_new_free_space(cache, root->fs_info,
8440                                            found_key.objectid,
8441                                            found_key.objectid +
8442                                            found_key.offset);
8443                         free_excluded_extents(root, cache);
8444                 }
8445
8446                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8447                 if (ret) {
8448                         btrfs_remove_free_space_cache(cache);
8449                         btrfs_put_block_group(cache);
8450                         goto error;
8451                 }
8452
8453                 ret = update_space_info(info, cache->flags, found_key.offset,
8454                                         btrfs_block_group_used(&cache->item),
8455                                         &space_info);
8456                 if (ret) {
8457                         btrfs_remove_free_space_cache(cache);
8458                         spin_lock(&info->block_group_cache_lock);
8459                         rb_erase(&cache->cache_node,
8460                                  &info->block_group_cache_tree);
8461                         spin_unlock(&info->block_group_cache_lock);
8462                         btrfs_put_block_group(cache);
8463                         goto error;
8464                 }
8465
8466                 cache->space_info = space_info;
8467                 spin_lock(&cache->space_info->lock);
8468                 cache->space_info->bytes_readonly += cache->bytes_super;
8469                 spin_unlock(&cache->space_info->lock);
8470
8471                 __link_block_group(space_info, cache);
8472
8473                 set_avail_alloc_bits(root->fs_info, cache->flags);
8474                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8475                         set_block_group_ro(cache, 1);
8476         }
8477
8478         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8479                 if (!(get_alloc_profile(root, space_info->flags) &
8480                       (BTRFS_BLOCK_GROUP_RAID10 |
8481                        BTRFS_BLOCK_GROUP_RAID1 |
8482                        BTRFS_BLOCK_GROUP_RAID5 |
8483                        BTRFS_BLOCK_GROUP_RAID6 |
8484                        BTRFS_BLOCK_GROUP_DUP)))
8485                         continue;
8486                 /*
8487                  * avoid allocating from un-mirrored block group if there are
8488                  * mirrored block groups.
8489                  */
8490                 list_for_each_entry(cache,
8491                                 &space_info->block_groups[BTRFS_RAID_RAID0],
8492                                 list)
8493                         set_block_group_ro(cache, 1);
8494                 list_for_each_entry(cache,
8495                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
8496                                 list)
8497                         set_block_group_ro(cache, 1);
8498         }
8499
8500         init_global_block_rsv(info);
8501         ret = 0;
8502 error:
8503         btrfs_free_path(path);
8504         return ret;
8505 }
8506
8507 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
8508                                        struct btrfs_root *root)
8509 {
8510         struct btrfs_block_group_cache *block_group, *tmp;
8511         struct btrfs_root *extent_root = root->fs_info->extent_root;
8512         struct btrfs_block_group_item item;
8513         struct btrfs_key key;
8514         int ret = 0;
8515
8516         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
8517                                  new_bg_list) {
8518                 list_del_init(&block_group->new_bg_list);
8519
8520                 if (ret)
8521                         continue;
8522
8523                 spin_lock(&block_group->lock);
8524                 memcpy(&item, &block_group->item, sizeof(item));
8525                 memcpy(&key, &block_group->key, sizeof(key));
8526                 spin_unlock(&block_group->lock);
8527
8528                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
8529                                         sizeof(item));
8530                 if (ret)
8531                         btrfs_abort_transaction(trans, extent_root, ret);
8532                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
8533                                                key.objectid, key.offset);
8534                 if (ret)
8535                         btrfs_abort_transaction(trans, extent_root, ret);
8536         }
8537 }
8538
8539 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8540                            struct btrfs_root *root, u64 bytes_used,
8541                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8542                            u64 size)
8543 {
8544         int ret;
8545         struct btrfs_root *extent_root;
8546         struct btrfs_block_group_cache *cache;
8547
8548         extent_root = root->fs_info->extent_root;
8549
8550         root->fs_info->last_trans_log_full_commit = trans->transid;
8551
8552         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8553         if (!cache)
8554                 return -ENOMEM;
8555         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8556                                         GFP_NOFS);
8557         if (!cache->free_space_ctl) {
8558                 kfree(cache);
8559                 return -ENOMEM;
8560         }
8561
8562         cache->key.objectid = chunk_offset;
8563         cache->key.offset = size;
8564         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8565         cache->sectorsize = root->sectorsize;
8566         cache->fs_info = root->fs_info;
8567         cache->full_stripe_len = btrfs_full_stripe_len(root,
8568                                                &root->fs_info->mapping_tree,
8569                                                chunk_offset);
8570
8571         atomic_set(&cache->count, 1);
8572         spin_lock_init(&cache->lock);
8573         INIT_LIST_HEAD(&cache->list);
8574         INIT_LIST_HEAD(&cache->cluster_list);
8575         INIT_LIST_HEAD(&cache->new_bg_list);
8576
8577         btrfs_init_free_space_ctl(cache);
8578
8579         btrfs_set_block_group_used(&cache->item, bytes_used);
8580         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8581         cache->flags = type;
8582         btrfs_set_block_group_flags(&cache->item, type);
8583
8584         cache->last_byte_to_unpin = (u64)-1;
8585         cache->cached = BTRFS_CACHE_FINISHED;
8586         ret = exclude_super_stripes(root, cache);
8587         if (ret) {
8588                 /*
8589                  * We may have excluded something, so call this just in
8590                  * case.
8591                  */
8592                 free_excluded_extents(root, cache);
8593                 kfree(cache->free_space_ctl);
8594                 kfree(cache);
8595                 return ret;
8596         }
8597
8598         add_new_free_space(cache, root->fs_info, chunk_offset,
8599                            chunk_offset + size);
8600
8601         free_excluded_extents(root, cache);
8602
8603         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8604         if (ret) {
8605                 btrfs_remove_free_space_cache(cache);
8606                 btrfs_put_block_group(cache);
8607                 return ret;
8608         }
8609
8610         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8611                                 &cache->space_info);
8612         if (ret) {
8613                 btrfs_remove_free_space_cache(cache);
8614                 spin_lock(&root->fs_info->block_group_cache_lock);
8615                 rb_erase(&cache->cache_node,
8616                          &root->fs_info->block_group_cache_tree);
8617                 spin_unlock(&root->fs_info->block_group_cache_lock);
8618                 btrfs_put_block_group(cache);
8619                 return ret;
8620         }
8621         update_global_block_rsv(root->fs_info);
8622
8623         spin_lock(&cache->space_info->lock);
8624         cache->space_info->bytes_readonly += cache->bytes_super;
8625         spin_unlock(&cache->space_info->lock);
8626
8627         __link_block_group(cache->space_info, cache);
8628
8629         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
8630
8631         set_avail_alloc_bits(extent_root->fs_info, type);
8632
8633         return 0;
8634 }
8635
8636 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
8637 {
8638         u64 extra_flags = chunk_to_extended(flags) &
8639                                 BTRFS_EXTENDED_PROFILE_MASK;
8640
8641         write_seqlock(&fs_info->profiles_lock);
8642         if (flags & BTRFS_BLOCK_GROUP_DATA)
8643                 fs_info->avail_data_alloc_bits &= ~extra_flags;
8644         if (flags & BTRFS_BLOCK_GROUP_METADATA)
8645                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
8646         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
8647                 fs_info->avail_system_alloc_bits &= ~extra_flags;
8648         write_sequnlock(&fs_info->profiles_lock);
8649 }
8650
8651 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8652                              struct btrfs_root *root, u64 group_start)
8653 {
8654         struct btrfs_path *path;
8655         struct btrfs_block_group_cache *block_group;
8656         struct btrfs_free_cluster *cluster;
8657         struct btrfs_root *tree_root = root->fs_info->tree_root;
8658         struct btrfs_key key;
8659         struct inode *inode;
8660         int ret;
8661         int index;
8662         int factor;
8663
8664         root = root->fs_info->extent_root;
8665
8666         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8667         BUG_ON(!block_group);
8668         BUG_ON(!block_group->ro);
8669
8670         /*
8671          * Free the reserved super bytes from this block group before
8672          * remove it.
8673          */
8674         free_excluded_extents(root, block_group);
8675
8676         memcpy(&key, &block_group->key, sizeof(key));
8677         index = get_block_group_index(block_group);
8678         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
8679                                   BTRFS_BLOCK_GROUP_RAID1 |
8680                                   BTRFS_BLOCK_GROUP_RAID10))
8681                 factor = 2;
8682         else
8683                 factor = 1;
8684
8685         /* make sure this block group isn't part of an allocation cluster */
8686         cluster = &root->fs_info->data_alloc_cluster;
8687         spin_lock(&cluster->refill_lock);
8688         btrfs_return_cluster_to_free_space(block_group, cluster);
8689         spin_unlock(&cluster->refill_lock);
8690
8691         /*
8692          * make sure this block group isn't part of a metadata
8693          * allocation cluster
8694          */
8695         cluster = &root->fs_info->meta_alloc_cluster;
8696         spin_lock(&cluster->refill_lock);
8697         btrfs_return_cluster_to_free_space(block_group, cluster);
8698         spin_unlock(&cluster->refill_lock);
8699
8700         path = btrfs_alloc_path();
8701         if (!path) {
8702                 ret = -ENOMEM;
8703                 goto out;
8704         }
8705
8706         inode = lookup_free_space_inode(tree_root, block_group, path);
8707         if (!IS_ERR(inode)) {
8708                 ret = btrfs_orphan_add(trans, inode);
8709                 if (ret) {
8710                         btrfs_add_delayed_iput(inode);
8711                         goto out;
8712                 }
8713                 clear_nlink(inode);
8714                 /* One for the block groups ref */
8715                 spin_lock(&block_group->lock);
8716                 if (block_group->iref) {
8717                         block_group->iref = 0;
8718                         block_group->inode = NULL;
8719                         spin_unlock(&block_group->lock);
8720                         iput(inode);
8721                 } else {
8722                         spin_unlock(&block_group->lock);
8723                 }
8724                 /* One for our lookup ref */
8725                 btrfs_add_delayed_iput(inode);
8726         }
8727
8728         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8729         key.offset = block_group->key.objectid;
8730         key.type = 0;
8731
8732         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8733         if (ret < 0)
8734                 goto out;
8735         if (ret > 0)
8736                 btrfs_release_path(path);
8737         if (ret == 0) {
8738                 ret = btrfs_del_item(trans, tree_root, path);
8739                 if (ret)
8740                         goto out;
8741                 btrfs_release_path(path);
8742         }
8743
8744         spin_lock(&root->fs_info->block_group_cache_lock);
8745         rb_erase(&block_group->cache_node,
8746                  &root->fs_info->block_group_cache_tree);
8747
8748         if (root->fs_info->first_logical_byte == block_group->key.objectid)
8749                 root->fs_info->first_logical_byte = (u64)-1;
8750         spin_unlock(&root->fs_info->block_group_cache_lock);
8751
8752         down_write(&block_group->space_info->groups_sem);
8753         /*
8754          * we must use list_del_init so people can check to see if they
8755          * are still on the list after taking the semaphore
8756          */
8757         list_del_init(&block_group->list);
8758         if (list_empty(&block_group->space_info->block_groups[index]))
8759                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8760         up_write(&block_group->space_info->groups_sem);
8761
8762         if (block_group->cached == BTRFS_CACHE_STARTED)
8763                 wait_block_group_cache_done(block_group);
8764
8765         btrfs_remove_free_space_cache(block_group);
8766
8767         spin_lock(&block_group->space_info->lock);
8768         block_group->space_info->total_bytes -= block_group->key.offset;
8769         block_group->space_info->bytes_readonly -= block_group->key.offset;
8770         block_group->space_info->disk_total -= block_group->key.offset * factor;
8771         spin_unlock(&block_group->space_info->lock);
8772
8773         memcpy(&key, &block_group->key, sizeof(key));
8774
8775         btrfs_clear_space_info_full(root->fs_info);
8776
8777         btrfs_put_block_group(block_group);
8778         btrfs_put_block_group(block_group);
8779
8780         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8781         if (ret > 0)
8782                 ret = -EIO;
8783         if (ret < 0)
8784                 goto out;
8785
8786         ret = btrfs_del_item(trans, root, path);
8787 out:
8788         btrfs_free_path(path);
8789         return ret;
8790 }
8791
8792 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8793 {
8794         struct btrfs_space_info *space_info;
8795         struct btrfs_super_block *disk_super;
8796         u64 features;
8797         u64 flags;
8798         int mixed = 0;
8799         int ret;
8800
8801         disk_super = fs_info->super_copy;
8802         if (!btrfs_super_root(disk_super))
8803                 return 1;
8804
8805         features = btrfs_super_incompat_flags(disk_super);
8806         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8807                 mixed = 1;
8808
8809         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8810         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8811         if (ret)
8812                 goto out;
8813
8814         if (mixed) {
8815                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8816                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8817         } else {
8818                 flags = BTRFS_BLOCK_GROUP_METADATA;
8819                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8820                 if (ret)
8821                         goto out;
8822
8823                 flags = BTRFS_BLOCK_GROUP_DATA;
8824                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8825         }
8826 out:
8827         return ret;
8828 }
8829
8830 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8831 {
8832         return unpin_extent_range(root, start, end);
8833 }
8834
8835 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8836                                u64 num_bytes, u64 *actual_bytes)
8837 {
8838         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8839 }
8840
8841 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8842 {
8843         struct btrfs_fs_info *fs_info = root->fs_info;
8844         struct btrfs_block_group_cache *cache = NULL;
8845         u64 group_trimmed;
8846         u64 start;
8847         u64 end;
8848         u64 trimmed = 0;
8849         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8850         int ret = 0;
8851
8852         /*
8853          * try to trim all FS space, our block group may start from non-zero.
8854          */
8855         if (range->len == total_bytes)
8856                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8857         else
8858                 cache = btrfs_lookup_block_group(fs_info, range->start);
8859
8860         while (cache) {
8861                 if (cache->key.objectid >= (range->start + range->len)) {
8862                         btrfs_put_block_group(cache);
8863                         break;
8864                 }
8865
8866                 start = max(range->start, cache->key.objectid);
8867                 end = min(range->start + range->len,
8868                                 cache->key.objectid + cache->key.offset);
8869
8870                 if (end - start >= range->minlen) {
8871                         if (!block_group_cache_done(cache)) {
8872                                 ret = cache_block_group(cache, 0);
8873                                 if (ret) {
8874                                         btrfs_put_block_group(cache);
8875                                         break;
8876                                 }
8877                                 ret = wait_block_group_cache_done(cache);
8878                                 if (ret) {
8879                                         btrfs_put_block_group(cache);
8880                                         break;
8881                                 }
8882                         }
8883                         ret = btrfs_trim_block_group(cache,
8884                                                      &group_trimmed,
8885                                                      start,
8886                                                      end,
8887                                                      range->minlen);
8888
8889                         trimmed += group_trimmed;
8890                         if (ret) {
8891                                 btrfs_put_block_group(cache);
8892                                 break;
8893                         }
8894                 }
8895
8896                 cache = next_block_group(fs_info->tree_root, cache);
8897         }
8898
8899         range->len = trimmed;
8900         return ret;
8901 }