kernel/fs/btrfs/extent-tree.c

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