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