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 "ctree.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "transaction.h"
  33 #include "volumes.h"
  34 #include "raid56.h"
  35 #include "locking.h"
  36 #include "free-space-cache.h"
  37 #include "math.h"
  38 #include "sysfs.h"
  39
  40 #undef SCRAMBLE_DELAYED_REFS
  41
  42 /*
  43  * control flags for do_chunk_alloc's force field
  44  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  45  * if we really need one.
  46  *
  47  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  48  * if we have very few chunks already allocated.  This is
  49  * used as part of the clustering code to help make sure
  50  * we have a good pool of storage to cluster in, without
  51  * filling the FS with empty chunks
  52  *
  53  * CHUNK_ALLOC_FORCE means it must try to allocate one
  54  *
  55  */
  56 enum {
  57         CHUNK_ALLOC_NO_FORCE = 0,
  58         CHUNK_ALLOC_LIMITED = 1,
  59         CHUNK_ALLOC_FORCE = 2,
  60 };
  61
  62 /*
  63  * Control how reservations are dealt with.
  64  *
  65  * RESERVE_FREE - freeing a reservation.
  66  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  67  *   ENOSPC accounting
  68  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  69  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  70  */
  71 enum {
  72         RESERVE_FREE = 0,
  73         RESERVE_ALLOC = 1,
  74         RESERVE_ALLOC_NO_ACCOUNT = 2,
  75 };
  76
  77 static int update_block_group(struct btrfs_root *root,
  78                               u64 bytenr, u64 num_bytes, int alloc);
  79 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  80                                 struct btrfs_root *root,
  81                                 u64 bytenr, u64 num_bytes, u64 parent,
  82                                 u64 root_objectid, u64 owner_objectid,
  83                                 u64 owner_offset, int refs_to_drop,
  84                                 struct btrfs_delayed_extent_op *extra_op);
  85 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  86                                     struct extent_buffer *leaf,
  87                                     struct btrfs_extent_item *ei);
  88 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  89                                       struct btrfs_root *root,
  90                                       u64 parent, u64 root_objectid,
  91                                       u64 flags, u64 owner, u64 offset,
  92                                       struct btrfs_key *ins, int ref_mod);
  93 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  94                                      struct btrfs_root *root,
  95                                      u64 parent, u64 root_objectid,
  96                                      u64 flags, struct btrfs_disk_key *key,
  97                                      int level, struct btrfs_key *ins);
  98 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  99                           struct btrfs_root *extent_root, u64 flags,
 100                           int force);
 101 static int find_next_key(struct btrfs_path *path, int level,
 102                          struct btrfs_key *key);
 103 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 104                             int dump_block_groups);
 105 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 106                                        u64 num_bytes, int reserve);
 107 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 108                                u64 num_bytes);
 109 int btrfs_pin_extent(struct btrfs_root *root,
 110                      u64 bytenr, u64 num_bytes, int reserved);
 111
 112 static noinline int
 113 block_group_cache_done(struct btrfs_block_group_cache *cache)
 114 {
 115         smp_mb();
 116         return cache->cached == BTRFS_CACHE_FINISHED ||
 117                 cache->cached == BTRFS_CACHE_ERROR;
 118 }
 119
 120 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 121 {
 122         return (cache->flags & bits) == bits;
 123 }
 124
 125 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 126 {
 127         atomic_inc(&cache->count);
 128 }
 129
 130 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 131 {
 132         if (atomic_dec_and_test(&cache->count)) {
 133                 WARN_ON(cache->pinned > 0);
 134                 WARN_ON(cache->reserved > 0);
 135                 kfree(cache->free_space_ctl);
 136                 kfree(cache);
 137         }
 138 }
 139
 140 /*
 141  * this adds the block group to the fs_info rb tree for the block group
 142  * cache
 143  */
 144 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 145                                 struct btrfs_block_group_cache *block_group)
 146 {
 147         struct rb_node **p;
 148         struct rb_node *parent = NULL;
 149         struct btrfs_block_group_cache *cache;
 150
 151         spin_lock(&info->block_group_cache_lock);
 152         p = &info->block_group_cache_tree.rb_node;
 153
 154         while (*p) {
 155                 parent = *p;
 156                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 157                                  cache_node);
 158                 if (block_group->key.objectid < cache->key.objectid) {
 159                         p = &(*p)->rb_left;
 160                 } else if (block_group->key.objectid > cache->key.objectid) {
 161                         p = &(*p)->rb_right;
 162                 } else {
 163                         spin_unlock(&info->block_group_cache_lock);
 164                         return -EEXIST;
 165                 }
 166         }
 167
 168         rb_link_node(&block_group->cache_node, parent, p);
 169         rb_insert_color(&block_group->cache_node,
 170                         &info->block_group_cache_tree);
 171
 172         if (info->first_logical_byte > block_group->key.objectid)
 173                 info->first_logical_byte = block_group->key.objectid;
 174
 175         spin_unlock(&info->block_group_cache_lock);
 176
 177         return 0;
 178 }
 179
 180 /*
 181  * This will return the block group at or after bytenr if contains is 0, else
 182  * it will return the block group that contains the bytenr
 183  */
 184 static struct btrfs_block_group_cache *
 185 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 186                               int contains)
 187 {
 188         struct btrfs_block_group_cache *cache, *ret = NULL;
 189         struct rb_node *n;
 190         u64 end, start;
 191
 192         spin_lock(&info->block_group_cache_lock);
 193         n = info->block_group_cache_tree.rb_node;
 194
 195         while (n) {
 196                 cache = rb_entry(n, struct btrfs_block_group_cache,
 197                                  cache_node);
 198                 end = cache->key.objectid + cache->key.offset - 1;
 199                 start = cache->key.objectid;
 200
 201                 if (bytenr < start) {
 202                         if (!contains && (!ret || start < ret->key.objectid))
 203                                 ret = cache;
 204                         n = n->rb_left;
 205                 } else if (bytenr > start) {
 206                         if (contains && bytenr <= end) {
 207                                 ret = cache;
 208                                 break;
 209                         }
 210                         n = n->rb_right;
 211                 } else {
 212                         ret = cache;
 213                         break;
 214                 }
 215         }
 216         if (ret) {
 217                 btrfs_get_block_group(ret);
 218                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 219                         info->first_logical_byte = ret->key.objectid;
 220         }
 221         spin_unlock(&info->block_group_cache_lock);
 222
 223         return ret;
 224 }
 225
 226 static int add_excluded_extent(struct btrfs_root *root,
 227                                u64 start, u64 num_bytes)
 228 {
 229         u64 end = start + num_bytes - 1;
 230         set_extent_bits(&root->fs_info->freed_extents[0],
 231                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 232         set_extent_bits(&root->fs_info->freed_extents[1],
 233                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 234         return 0;
 235 }
 236
 237 static void free_excluded_extents(struct btrfs_root *root,
 238                                   struct btrfs_block_group_cache *cache)
 239 {
 240         u64 start, end;
 241
 242         start = cache->key.objectid;
 243         end = start + cache->key.offset - 1;
 244
 245         clear_extent_bits(&root->fs_info->freed_extents[0],
 246                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 247         clear_extent_bits(&root->fs_info->freed_extents[1],
 248                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 249 }
 250
 251 static int exclude_super_stripes(struct btrfs_root *root,
 252                                  struct btrfs_block_group_cache *cache)
 253 {
 254         u64 bytenr;
 255         u64 *logical;
 256         int stripe_len;
 257         int i, nr, ret;
 258
 259         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 260                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 261                 cache->bytes_super += stripe_len;
 262                 ret = add_excluded_extent(root, cache->key.objectid,
 263                                           stripe_len);
 264                 if (ret)
 265                         return ret;
 266         }
 267
 268         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 269                 bytenr = btrfs_sb_offset(i);
 270                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 271                                        cache->key.objectid, bytenr,
 272                                        0, &logical, &nr, &stripe_len);
 273                 if (ret)
 274                         return ret;
 275
 276                 while (nr--) {
 277                         u64 start, len;
 278
 279                         if (logical[nr] > cache->key.objectid +
 280                             cache->key.offset)
 281                                 continue;
 282
 283                         if (logical[nr] + stripe_len <= cache->key.objectid)
 284                                 continue;
 285
 286                         start = logical[nr];
 287                         if (start < cache->key.objectid) {
 288                                 start = cache->key.objectid;
 289                                 len = (logical[nr] + stripe_len) - start;
 290                         } else {
 291                                 len = min_t(u64, stripe_len,
 292                                             cache->key.objectid +
 293                                             cache->key.offset - start);
 294                         }
 295
 296                         cache->bytes_super += len;
 297                         ret = add_excluded_extent(root, start, len);
 298                         if (ret) {
 299                                 kfree(logical);
 300                                 return ret;
 301                         }
 302                 }
 303
 304                 kfree(logical);
 305         }
 306         return 0;
 307 }
 308
 309 static struct btrfs_caching_control *
 310 get_caching_control(struct btrfs_block_group_cache *cache)
 311 {
 312         struct btrfs_caching_control *ctl;
 313
 314         spin_lock(&cache->lock);
 315         if (cache->cached != BTRFS_CACHE_STARTED) {
 316                 spin_unlock(&cache->lock);
 317                 return NULL;
 318         }
 319
 320         /* We're loading it the fast way, so we don't have a caching_ctl. */
 321         if (!cache->caching_ctl) {
 322                 spin_unlock(&cache->lock);
 323                 return NULL;
 324         }
 325
 326         ctl = cache->caching_ctl;
 327         atomic_inc(&ctl->count);
 328         spin_unlock(&cache->lock);
 329         return ctl;
 330 }
 331
 332 static void put_caching_control(struct btrfs_caching_control *ctl)
 333 {
 334         if (atomic_dec_and_test(&ctl->count))
 335                 kfree(ctl);
 336 }
 337
 338 /*
 339  * this is only called by cache_block_group, since we could have freed extents
 340  * we need to check the pinned_extents for any extents that can't be used yet
 341  * since their free space will be released as soon as the transaction commits.
 342  */
 343 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 344                               struct btrfs_fs_info *info, u64 start, u64 end)
 345 {
 346         u64 extent_start, extent_end, size, total_added = 0;
 347         int ret;
 348
 349         while (start < end) {
 350                 ret = find_first_extent_bit(info->pinned_extents, start,
 351                                             &extent_start, &extent_end,
 352                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 353                                             NULL);
 354                 if (ret)
 355                         break;
 356
 357                 if (extent_start <= start) {
 358                         start = extent_end + 1;
 359                 } else if (extent_start > start && extent_start < end) {
 360                         size = extent_start - start;
 361                         total_added += size;
 362                         ret = btrfs_add_free_space(block_group, start,
 363                                                    size);
 364                         BUG_ON(ret); /* -ENOMEM or logic error */
 365                         start = extent_end + 1;
 366                 } else {
 367                         break;
 368                 }
 369         }
 370
 371         if (start < end) {
 372                 size = end - start;
 373                 total_added += size;
 374                 ret = btrfs_add_free_space(block_group, start, size);
 375                 BUG_ON(ret); /* -ENOMEM or logic error */
 376         }
 377
 378         return total_added;
 379 }
 380
 381 static noinline void caching_thread(struct btrfs_work *work)
 382 {
 383         struct btrfs_block_group_cache *block_group;
 384         struct btrfs_fs_info *fs_info;
 385         struct btrfs_caching_control *caching_ctl;
 386         struct btrfs_root *extent_root;
 387         struct btrfs_path *path;
 388         struct extent_buffer *leaf;
 389         struct btrfs_key key;
 390         u64 total_found = 0;
 391         u64 last = 0;
 392         u32 nritems;
 393         int ret = -ENOMEM;
 394
 395         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 396         block_group = caching_ctl->block_group;
 397         fs_info = block_group->fs_info;
 398         extent_root = fs_info->extent_root;
 399
 400         path = btrfs_alloc_path();
 401         if (!path)
 402                 goto out;
 403
 404         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 405
 406         /*
 407          * We don't want to deadlock with somebody trying to allocate a new
 408          * extent for the extent root while also trying to search the extent
 409          * root to add free space.  So we skip locking and search the commit
 410          * root, since its read-only
 411          */
 412         path->skip_locking = 1;
 413         path->search_commit_root = 1;
 414         path->reada = 1;
 415
 416         key.objectid = last;
 417         key.offset = 0;
 418         key.type = BTRFS_EXTENT_ITEM_KEY;
 419 again:
 420         mutex_lock(&caching_ctl->mutex);
 421         /* need to make sure the commit_root doesn't disappear */
 422         down_read(&fs_info->extent_commit_sem);
 423
 424 next:
 425         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 426         if (ret < 0)
 427                 goto err;
 428
 429         leaf = path->nodes[0];
 430         nritems = btrfs_header_nritems(leaf);
 431
 432         while (1) {
 433                 if (btrfs_fs_closing(fs_info) > 1) {
 434                         last = (u64)-1;
 435                         break;
 436                 }
 437
 438                 if (path->slots[0] < nritems) {
 439                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 440                 } else {
 441                         ret = find_next_key(path, 0, &key);
 442                         if (ret)
 443                                 break;
 444
 445                         if (need_resched() ||
 446                             rwsem_is_contended(&fs_info->extent_commit_sem)) {
 447                                 caching_ctl->progress = last;
 448                                 btrfs_release_path(path);
 449                                 up_read(&fs_info->extent_commit_sem);
 450                                 mutex_unlock(&caching_ctl->mutex);
 451                                 cond_resched();
 452                                 goto again;
 453                         }
 454
 455                         ret = btrfs_next_leaf(extent_root, path);
 456                         if (ret < 0)
 457                                 goto err;
 458                         if (ret)
 459                                 break;
 460                         leaf = path->nodes[0];
 461                         nritems = btrfs_header_nritems(leaf);
 462                         continue;
 463                 }
 464
 465                 if (key.objectid < last) {
 466                         key.objectid = last;
 467                         key.offset = 0;
 468                         key.type = BTRFS_EXTENT_ITEM_KEY;
 469
 470                         caching_ctl->progress = last;
 471                         btrfs_release_path(path);
 472                         goto next;
 473                 }
 474
 475                 if (key.objectid < block_group->key.objectid) {
 476                         path->slots[0]++;
 477                         continue;
 478                 }
 479
 480                 if (key.objectid >= block_group->key.objectid +
 481                     block_group->key.offset)
 482                         break;
 483
 484                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 485                     key.type == BTRFS_METADATA_ITEM_KEY) {
 486                         total_found += add_new_free_space(block_group,
 487                                                           fs_info, last,
 488                                                           key.objectid);
 489                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 490                                 last = key.objectid +
 491                                         fs_info->tree_root->leafsize;
 492                         else
 493                                 last = key.objectid + key.offset;
 494
 495                         if (total_found > (1024 * 1024 * 2)) {
 496                                 total_found = 0;
 497                                 wake_up(&caching_ctl->wait);
 498                         }
 499                 }
 500                 path->slots[0]++;
 501         }
 502         ret = 0;
 503
 504         total_found += add_new_free_space(block_group, fs_info, last,
 505                                           block_group->key.objectid +
 506                                           block_group->key.offset);
 507         caching_ctl->progress = (u64)-1;
 508
 509         spin_lock(&block_group->lock);
 510         block_group->caching_ctl = NULL;
 511         block_group->cached = BTRFS_CACHE_FINISHED;
 512         spin_unlock(&block_group->lock);
 513
 514 err:
 515         btrfs_free_path(path);
 516         up_read(&fs_info->extent_commit_sem);
 517
 518         free_excluded_extents(extent_root, block_group);
 519
 520         mutex_unlock(&caching_ctl->mutex);
 521 out:
 522         if (ret) {
 523                 spin_lock(&block_group->lock);
 524                 block_group->caching_ctl = NULL;
 525                 block_group->cached = BTRFS_CACHE_ERROR;
 526                 spin_unlock(&block_group->lock);
 527         }
 528         wake_up(&caching_ctl->wait);
 529
 530         put_caching_control(caching_ctl);
 531         btrfs_put_block_group(block_group);
 532 }
 533
 534 static int cache_block_group(struct btrfs_block_group_cache *cache,
 535                              int load_cache_only)
 536 {
 537         DEFINE_WAIT(wait);
 538         struct btrfs_fs_info *fs_info = cache->fs_info;
 539         struct btrfs_caching_control *caching_ctl;
 540         int ret = 0;
 541
 542         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 543         if (!caching_ctl)
 544                 return -ENOMEM;
 545
 546         INIT_LIST_HEAD(&caching_ctl->list);
 547         mutex_init(&caching_ctl->mutex);
 548         init_waitqueue_head(&caching_ctl->wait);
 549         caching_ctl->block_group = cache;
 550         caching_ctl->progress = cache->key.objectid;
 551         atomic_set(&caching_ctl->count, 1);
 552         caching_ctl->work.func = caching_thread;
 553
 554         spin_lock(&cache->lock);
 555         /*
 556          * This should be a rare occasion, but this could happen I think in the
 557          * case where one thread starts to load the space cache info, and then
 558          * some other thread starts a transaction commit which tries to do an
 559          * allocation while the other thread is still loading the space cache
 560          * info.  The previous loop should have kept us from choosing this block
 561          * group, but if we've moved to the state where we will wait on caching
 562          * block groups we need to first check if we're doing a fast load here,
 563          * so we can wait for it to finish, otherwise we could end up allocating
 564          * from a block group who's cache gets evicted for one reason or
 565          * another.
 566          */
 567         while (cache->cached == BTRFS_CACHE_FAST) {
 568                 struct btrfs_caching_control *ctl;
 569
 570                 ctl = cache->caching_ctl;
 571                 atomic_inc(&ctl->count);
 572                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 573                 spin_unlock(&cache->lock);
 574
 575                 schedule();
 576
 577                 finish_wait(&ctl->wait, &wait);
 578                 put_caching_control(ctl);
 579                 spin_lock(&cache->lock);
 580         }
 581
 582         if (cache->cached != BTRFS_CACHE_NO) {
 583                 spin_unlock(&cache->lock);
 584                 kfree(caching_ctl);
 585                 return 0;
 586         }
 587         WARN_ON(cache->caching_ctl);
 588         cache->caching_ctl = caching_ctl;
 589         cache->cached = BTRFS_CACHE_FAST;
 590         spin_unlock(&cache->lock);
 591
 592         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 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                 } else {
 601                         if (load_cache_only) {
 602                                 cache->caching_ctl = NULL;
 603                                 cache->cached = BTRFS_CACHE_NO;
 604                         } else {
 605                                 cache->cached = BTRFS_CACHE_STARTED;
 606                         }
 607                 }
 608                 spin_unlock(&cache->lock);
 609                 wake_up(&caching_ctl->wait);
 610                 if (ret == 1) {
 611                         put_caching_control(caching_ctl);
 612                         free_excluded_extents(fs_info->extent_root, cache);
 613                         return 0;
 614                 }
 615         } else {
 616                 /*
 617                  * We are not going to do the fast caching, set cached to the
 618                  * appropriate value and wakeup any waiters.
 619                  */
 620                 spin_lock(&cache->lock);
 621                 if (load_cache_only) {
 622                         cache->caching_ctl = NULL;
 623                         cache->cached = BTRFS_CACHE_NO;
 624                 } else {
 625                         cache->cached = BTRFS_CACHE_STARTED;
 626                 }
 627                 spin_unlock(&cache->lock);
 628                 wake_up(&caching_ctl->wait);
 629         }
 630
 631         if (load_cache_only) {
 632                 put_caching_control(caching_ctl);
 633                 return 0;
 634         }
 635
 636         down_write(&fs_info->extent_commit_sem);
 637         atomic_inc(&caching_ctl->count);
 638         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 639         up_write(&fs_info->extent_commit_sem);
 640
 641         btrfs_get_block_group(cache);
 642
 643         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 644
 645         return ret;
 646 }
 647
 648 /*
 649  * return the block group that starts at or after bytenr
 650  */
 651 static struct btrfs_block_group_cache *
 652 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 653 {
 654         struct btrfs_block_group_cache *cache;
 655
 656         cache = block_group_cache_tree_search(info, bytenr, 0);
 657
 658         return cache;
 659 }
 660
 661 /*
 662  * return the block group that contains the given bytenr
 663  */
 664 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 665                                                  struct btrfs_fs_info *info,
 666                                                  u64 bytenr)
 667 {
 668         struct btrfs_block_group_cache *cache;
 669
 670         cache = block_group_cache_tree_search(info, bytenr, 1);
 671
 672         return cache;
 673 }
 674
 675 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 676                                                   u64 flags)
 677 {
 678         struct list_head *head = &info->space_info;
 679         struct btrfs_space_info *found;
 680
 681         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 682
 683         rcu_read_lock();
 684         list_for_each_entry_rcu(found, head, list) {
 685                 if (found->flags & flags) {
 686                         rcu_read_unlock();
 687                         return found;
 688                 }
 689         }
 690         rcu_read_unlock();
 691         return NULL;
 692 }
 693
 694 /*
 695  * after adding space to the filesystem, we need to clear the full flags
 696  * on all the space infos.
 697  */
 698 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 699 {
 700         struct list_head *head = &info->space_info;
 701         struct btrfs_space_info *found;
 702
 703         rcu_read_lock();
 704         list_for_each_entry_rcu(found, head, list)
 705                 found->full = 0;
 706         rcu_read_unlock();
 707 }
 708
 709 /* simple helper to search for an existing extent at a given offset */
 710 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 711 {
 712         int ret;
 713         struct btrfs_key key;
 714         struct btrfs_path *path;
 715
 716         path = btrfs_alloc_path();
 717         if (!path)
 718                 return -ENOMEM;
 719
 720         key.objectid = start;
 721         key.offset = len;
 722         key.type = BTRFS_EXTENT_ITEM_KEY;
 723         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 724                                 0, 0);
 725         if (ret > 0) {
 726                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 727                 if (key.objectid == start &&
 728                     key.type == BTRFS_METADATA_ITEM_KEY)
 729                         ret = 0;
 730         }
 731         btrfs_free_path(path);
 732         return ret;
 733 }
 734
 735 /*
 736  * helper function to lookup reference count and flags of a tree block.
 737  *
 738  * the head node for delayed ref is used to store the sum of all the
 739  * reference count modifications queued up in the rbtree. the head
 740  * node may also store the extent flags to set. This way you can check
 741  * to see what the reference count and extent flags would be if all of
 742  * the delayed refs are not processed.
 743  */
 744 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 745                              struct btrfs_root *root, u64 bytenr,
 746                              u64 offset, int metadata, u64 *refs, u64 *flags)
 747 {
 748         struct btrfs_delayed_ref_head *head;
 749         struct btrfs_delayed_ref_root *delayed_refs;
 750         struct btrfs_path *path;
 751         struct btrfs_extent_item *ei;
 752         struct extent_buffer *leaf;
 753         struct btrfs_key key;
 754         u32 item_size;
 755         u64 num_refs;
 756         u64 extent_flags;
 757         int ret;
 758
 759         /*
 760          * If we don't have skinny metadata, don't bother doing anything
 761          * different
 762          */
 763         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 764                 offset = root->leafsize;
 765                 metadata = 0;
 766         }
 767
 768         path = btrfs_alloc_path();
 769         if (!path)
 770                 return -ENOMEM;
 771
 772         if (!trans) {
 773                 path->skip_locking = 1;
 774                 path->search_commit_root = 1;
 775         }
 776
 777 search_again:
 778         key.objectid = bytenr;
 779         key.offset = offset;
 780         if (metadata)
 781                 key.type = BTRFS_METADATA_ITEM_KEY;
 782         else
 783                 key.type = BTRFS_EXTENT_ITEM_KEY;
 784
 785 again:
 786         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 787                                 &key, path, 0, 0);
 788         if (ret < 0)
 789                 goto out_free;
 790
 791         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 792                 if (path->slots[0]) {
 793                         path->slots[0]--;
 794                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 795                                               path->slots[0]);
 796                         if (key.objectid == bytenr &&
 797                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 798                             key.offset == root->leafsize)
 799                                 ret = 0;
 800                 }
 801                 if (ret) {
 802                         key.objectid = bytenr;
 803                         key.type = BTRFS_EXTENT_ITEM_KEY;
 804                         key.offset = root->leafsize;
 805                         btrfs_release_path(path);
 806                         goto again;
 807                 }
 808         }
 809
 810         if (ret == 0) {
 811                 leaf = path->nodes[0];
 812                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 813                 if (item_size >= sizeof(*ei)) {
 814                         ei = btrfs_item_ptr(leaf, path->slots[0],
 815                                             struct btrfs_extent_item);
 816                         num_refs = btrfs_extent_refs(leaf, ei);
 817                         extent_flags = btrfs_extent_flags(leaf, ei);
 818                 } else {
 819 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 820                         struct btrfs_extent_item_v0 *ei0;
 821                         BUG_ON(item_size != sizeof(*ei0));
 822                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 823                                              struct btrfs_extent_item_v0);
 824                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 825                         /* FIXME: this isn't correct for data */
 826                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 827 #else
 828                         BUG();
 829 #endif
 830                 }
 831                 BUG_ON(num_refs == 0);
 832         } else {
 833                 num_refs = 0;
 834                 extent_flags = 0;
 835                 ret = 0;
 836         }
 837
 838         if (!trans)
 839                 goto out;
 840
 841         delayed_refs = &trans->transaction->delayed_refs;
 842         spin_lock(&delayed_refs->lock);
 843         head = btrfs_find_delayed_ref_head(trans, bytenr);
 844         if (head) {
 845                 if (!mutex_trylock(&head->mutex)) {
 846                         atomic_inc(&head->node.refs);
 847                         spin_unlock(&delayed_refs->lock);
 848
 849                         btrfs_release_path(path);
 850
 851                         /*
 852                          * Mutex was contended, block until it's released and try
 853                          * again
 854                          */
 855                         mutex_lock(&head->mutex);
 856                         mutex_unlock(&head->mutex);
 857                         btrfs_put_delayed_ref(&head->node);
 858                         goto search_again;
 859                 }
 860                 spin_lock(&head->lock);
 861                 if (head->extent_op && head->extent_op->update_flags)
 862                         extent_flags |= head->extent_op->flags_to_set;
 863                 else
 864                         BUG_ON(num_refs == 0);
 865
 866                 num_refs += head->node.ref_mod;
 867                 spin_unlock(&head->lock);
 868                 mutex_unlock(&head->mutex);
 869         }
 870         spin_unlock(&delayed_refs->lock);
 871 out:
 872         WARN_ON(num_refs == 0);
 873         if (refs)
 874                 *refs = num_refs;
 875         if (flags)
 876                 *flags = extent_flags;
 877 out_free:
 878         btrfs_free_path(path);
 879         return ret;
 880 }
 881
 882 /*
 883  * Back reference rules.  Back refs have three main goals:
 884  *
 885  * 1) differentiate between all holders of references to an extent so that
 886  *    when a reference is dropped we can make sure it was a valid reference
 887  *    before freeing the extent.
 888  *
 889  * 2) Provide enough information to quickly find the holders of an extent
 890  *    if we notice a given block is corrupted or bad.
 891  *
 892  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 893  *    maintenance.  This is actually the same as #2, but with a slightly
 894  *    different use case.
 895  *
 896  * There are two kinds of back refs. The implicit back refs is optimized
 897  * for pointers in non-shared tree blocks. For a given pointer in a block,
 898  * back refs of this kind provide information about the block's owner tree
 899  * and the pointer's key. These information allow us to find the block by
 900  * b-tree searching. The full back refs is for pointers in tree blocks not
 901  * referenced by their owner trees. The location of tree block is recorded
 902  * in the back refs. Actually the full back refs is generic, and can be
 903  * used in all cases the implicit back refs is used. The major shortcoming
 904  * of the full back refs is its overhead. Every time a tree block gets
 905  * COWed, we have to update back refs entry for all pointers in it.
 906  *
 907  * For a newly allocated tree block, we use implicit back refs for
 908  * pointers in it. This means most tree related operations only involve
 909  * implicit back refs. For a tree block created in old transaction, the
 910  * only way to drop a reference to it is COW it. So we can detect the
 911  * event that tree block loses its owner tree's reference and do the
 912  * back refs conversion.
 913  *
 914  * When a tree block is COW'd through a tree, there are four cases:
 915  *
 916  * The reference count of the block is one and the tree is the block's
 917  * owner tree. Nothing to do in this case.
 918  *
 919  * The reference count of the block is one and the tree is not the
 920  * block's owner tree. In this case, full back refs is used for pointers
 921  * in the block. Remove these full back refs, add implicit back refs for
 922  * every pointers in the new block.
 923  *
 924  * The reference count of the block is greater than one and the tree is
 925  * the block's owner tree. In this case, implicit back refs is used for
 926  * pointers in the block. Add full back refs for every pointers in the
 927  * block, increase lower level extents' reference counts. The original
 928  * implicit back refs are entailed to the new block.
 929  *
 930  * The reference count of the block is greater than one and the tree is
 931  * not the block's owner tree. Add implicit back refs for every pointer in
 932  * the new block, increase lower level extents' reference count.
 933  *
 934  * Back Reference Key composing:
 935  *
 936  * The key objectid corresponds to the first byte in the extent,
 937  * The key type is used to differentiate between types of back refs.
 938  * There are different meanings of the key offset for different types
 939  * of back refs.
 940  *
 941  * File extents can be referenced by:
 942  *
 943  * - multiple snapshots, subvolumes, or different generations in one subvol
 944  * - different files inside a single subvolume
 945  * - different offsets inside a file (bookend extents in file.c)
 946  *
 947  * The extent ref structure for the implicit back refs has fields for:
 948  *
 949  * - Objectid of the subvolume root
 950  * - objectid of the file holding the reference
 951  * - original offset in the file
 952  * - how many bookend extents
 953  *
 954  * The key offset for the implicit back refs is hash of the first
 955  * three fields.
 956  *
 957  * The extent ref structure for the full back refs has field for:
 958  *
 959  * - number of pointers in the tree leaf
 960  *
 961  * The key offset for the implicit back refs is the first byte of
 962  * the tree leaf
 963  *
 964  * When a file extent is allocated, The implicit back refs is used.
 965  * the fields are filled in:
 966  *
 967  *     (root_key.objectid, inode objectid, offset in file, 1)
 968  *
 969  * When a file extent is removed file truncation, we find the
 970  * corresponding implicit back refs and check the following fields:
 971  *
 972  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 973  *
 974  * Btree extents can be referenced by:
 975  *
 976  * - Different subvolumes
 977  *
 978  * Both the implicit back refs and the full back refs for tree blocks
 979  * only consist of key. The key offset for the implicit back refs is
 980  * objectid of block's owner tree. The key offset for the full back refs
 981  * is the first byte of parent block.
 982  *
 983  * When implicit back refs is used, information about the lowest key and
 984  * level of the tree block are required. These information are stored in
 985  * tree block info structure.
 986  */
 987
 988 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 989 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 990                                   struct btrfs_root *root,
 991                                   struct btrfs_path *path,
 992                                   u64 owner, u32 extra_size)
 993 {
 994         struct btrfs_extent_item *item;
 995         struct btrfs_extent_item_v0 *ei0;
 996         struct btrfs_extent_ref_v0 *ref0;
 997         struct btrfs_tree_block_info *bi;
 998         struct extent_buffer *leaf;
 999         struct btrfs_key key;
1000         struct btrfs_key found_key;
1001         u32 new_size = sizeof(*item);
1002         u64 refs;
1003         int ret;
1004
1005         leaf = path->nodes[0];
1006         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1007
1008         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1009         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1010                              struct btrfs_extent_item_v0);
1011         refs = btrfs_extent_refs_v0(leaf, ei0);
1012
1013         if (owner == (u64)-1) {
1014                 while (1) {
1015                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1016                                 ret = btrfs_next_leaf(root, path);
1017                                 if (ret < 0)
1018                                         return ret;
1019                                 BUG_ON(ret > 0); /* Corruption */
1020                                 leaf = path->nodes[0];
1021                         }
1022                         btrfs_item_key_to_cpu(leaf, &found_key,
1023                                               path->slots[0]);
1024                         BUG_ON(key.objectid != found_key.objectid);
1025                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1026                                 path->slots[0]++;
1027                                 continue;
1028                         }
1029                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1030                                               struct btrfs_extent_ref_v0);
1031                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1032                         break;
1033                 }
1034         }
1035         btrfs_release_path(path);
1036
1037         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1038                 new_size += sizeof(*bi);
1039
1040         new_size -= sizeof(*ei0);
1041         ret = btrfs_search_slot(trans, root, &key, path,
1042                                 new_size + extra_size, 1);
1043         if (ret < 0)
1044                 return ret;
1045         BUG_ON(ret); /* Corruption */
1046
1047         btrfs_extend_item(root, path, new_size);
1048
1049         leaf = path->nodes[0];
1050         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1051         btrfs_set_extent_refs(leaf, item, refs);
1052         /* FIXME: get real generation */
1053         btrfs_set_extent_generation(leaf, item, 0);
1054         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1055                 btrfs_set_extent_flags(leaf, item,
1056                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1057                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1058                 bi = (struct btrfs_tree_block_info *)(item + 1);
1059                 /* FIXME: get first key of the block */
1060                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1061                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1062         } else {
1063                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1064         }
1065         btrfs_mark_buffer_dirty(leaf);
1066         return 0;
1067 }
1068 #endif
1069
1070 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1071 {
1072         u32 high_crc = ~(u32)0;
1073         u32 low_crc = ~(u32)0;
1074         __le64 lenum;
1075
1076         lenum = cpu_to_le64(root_objectid);
1077         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1078         lenum = cpu_to_le64(owner);
1079         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1080         lenum = cpu_to_le64(offset);
1081         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1082
1083         return ((u64)high_crc << 31) ^ (u64)low_crc;
1084 }
1085
1086 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1087                                      struct btrfs_extent_data_ref *ref)
1088 {
1089         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1090                                     btrfs_extent_data_ref_objectid(leaf, ref),
1091                                     btrfs_extent_data_ref_offset(leaf, ref));
1092 }
1093
1094 static int match_extent_data_ref(struct extent_buffer *leaf,
1095                                  struct btrfs_extent_data_ref *ref,
1096                                  u64 root_objectid, u64 owner, u64 offset)
1097 {
1098         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1099             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1100             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1101                 return 0;
1102         return 1;
1103 }
1104
1105 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1106                                            struct btrfs_root *root,
1107                                            struct btrfs_path *path,
1108                                            u64 bytenr, u64 parent,
1109                                            u64 root_objectid,
1110                                            u64 owner, u64 offset)
1111 {
1112         struct btrfs_key key;
1113         struct btrfs_extent_data_ref *ref;
1114         struct extent_buffer *leaf;
1115         u32 nritems;
1116         int ret;
1117         int recow;
1118         int err = -ENOENT;
1119
1120         key.objectid = bytenr;
1121         if (parent) {
1122                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1123                 key.offset = parent;
1124         } else {
1125                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1126                 key.offset = hash_extent_data_ref(root_objectid,
1127                                                   owner, offset);
1128         }
1129 again:
1130         recow = 0;
1131         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1132         if (ret < 0) {
1133                 err = ret;
1134                 goto fail;
1135         }
1136
1137         if (parent) {
1138                 if (!ret)
1139                         return 0;
1140 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1141                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1142                 btrfs_release_path(path);
1143                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1144                 if (ret < 0) {
1145                         err = ret;
1146                         goto fail;
1147                 }
1148                 if (!ret)
1149                         return 0;
1150 #endif
1151                 goto fail;
1152         }
1153
1154         leaf = path->nodes[0];
1155         nritems = btrfs_header_nritems(leaf);
1156         while (1) {
1157                 if (path->slots[0] >= nritems) {
1158                         ret = btrfs_next_leaf(root, path);
1159                         if (ret < 0)
1160                                 err = ret;
1161                         if (ret)
1162                                 goto fail;
1163
1164                         leaf = path->nodes[0];
1165                         nritems = btrfs_header_nritems(leaf);
1166                         recow = 1;
1167                 }
1168
1169                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1170                 if (key.objectid != bytenr ||
1171                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1172                         goto fail;
1173
1174                 ref = btrfs_item_ptr(leaf, path->slots[0],
1175                                      struct btrfs_extent_data_ref);
1176
1177                 if (match_extent_data_ref(leaf, ref, root_objectid,
1178                                           owner, offset)) {
1179                         if (recow) {
1180                                 btrfs_release_path(path);
1181                                 goto again;
1182                         }
1183                         err = 0;
1184                         break;
1185                 }
1186                 path->slots[0]++;
1187         }
1188 fail:
1189         return err;
1190 }
1191
1192 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1193                                            struct btrfs_root *root,
1194                                            struct btrfs_path *path,
1195                                            u64 bytenr, u64 parent,
1196                                            u64 root_objectid, u64 owner,
1197                                            u64 offset, int refs_to_add)
1198 {
1199         struct btrfs_key key;
1200         struct extent_buffer *leaf;
1201         u32 size;
1202         u32 num_refs;
1203         int ret;
1204
1205         key.objectid = bytenr;
1206         if (parent) {
1207                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1208                 key.offset = parent;
1209                 size = sizeof(struct btrfs_shared_data_ref);
1210         } else {
1211                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1212                 key.offset = hash_extent_data_ref(root_objectid,
1213                                                   owner, offset);
1214                 size = sizeof(struct btrfs_extent_data_ref);
1215         }
1216
1217         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1218         if (ret && ret != -EEXIST)
1219                 goto fail;
1220
1221         leaf = path->nodes[0];
1222         if (parent) {
1223                 struct btrfs_shared_data_ref *ref;
1224                 ref = btrfs_item_ptr(leaf, path->slots[0],
1225                                      struct btrfs_shared_data_ref);
1226                 if (ret == 0) {
1227                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1228                 } else {
1229                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1230                         num_refs += refs_to_add;
1231                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1232                 }
1233         } else {
1234                 struct btrfs_extent_data_ref *ref;
1235                 while (ret == -EEXIST) {
1236                         ref = btrfs_item_ptr(leaf, path->slots[0],
1237                                              struct btrfs_extent_data_ref);
1238                         if (match_extent_data_ref(leaf, ref, root_objectid,
1239                                                   owner, offset))
1240                                 break;
1241                         btrfs_release_path(path);
1242                         key.offset++;
1243                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1244                                                       size);
1245                         if (ret && ret != -EEXIST)
1246                                 goto fail;
1247
1248                         leaf = path->nodes[0];
1249                 }
1250                 ref = btrfs_item_ptr(leaf, path->slots[0],
1251                                      struct btrfs_extent_data_ref);
1252                 if (ret == 0) {
1253                         btrfs_set_extent_data_ref_root(leaf, ref,
1254                                                        root_objectid);
1255                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1256                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1257                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1258                 } else {
1259                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1260                         num_refs += refs_to_add;
1261                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1262                 }
1263         }
1264         btrfs_mark_buffer_dirty(leaf);
1265         ret = 0;
1266 fail:
1267         btrfs_release_path(path);
1268         return ret;
1269 }
1270
1271 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1272                                            struct btrfs_root *root,
1273                                            struct btrfs_path *path,
1274                                            int refs_to_drop)
1275 {
1276         struct btrfs_key key;
1277         struct btrfs_extent_data_ref *ref1 = NULL;
1278         struct btrfs_shared_data_ref *ref2 = NULL;
1279         struct extent_buffer *leaf;
1280         u32 num_refs = 0;
1281         int ret = 0;
1282
1283         leaf = path->nodes[0];
1284         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1285
1286         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1287                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1288                                       struct btrfs_extent_data_ref);
1289                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1290         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1291                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1292                                       struct btrfs_shared_data_ref);
1293                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1294 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1295         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1296                 struct btrfs_extent_ref_v0 *ref0;
1297                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1298                                       struct btrfs_extent_ref_v0);
1299                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1300 #endif
1301         } else {
1302                 BUG();
1303         }
1304
1305         BUG_ON(num_refs < refs_to_drop);
1306         num_refs -= refs_to_drop;
1307
1308         if (num_refs == 0) {
1309                 ret = btrfs_del_item(trans, root, path);
1310         } else {
1311                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1312                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1313                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1314                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1315 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1316                 else {
1317                         struct btrfs_extent_ref_v0 *ref0;
1318                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1319                                         struct btrfs_extent_ref_v0);
1320                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1321                 }
1322 #endif
1323                 btrfs_mark_buffer_dirty(leaf);
1324         }
1325         return ret;
1326 }
1327
1328 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1329                                           struct btrfs_path *path,
1330                                           struct btrfs_extent_inline_ref *iref)
1331 {
1332         struct btrfs_key key;
1333         struct extent_buffer *leaf;
1334         struct btrfs_extent_data_ref *ref1;
1335         struct btrfs_shared_data_ref *ref2;
1336         u32 num_refs = 0;
1337
1338         leaf = path->nodes[0];
1339         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1340         if (iref) {
1341                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1342                     BTRFS_EXTENT_DATA_REF_KEY) {
1343                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1344                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1345                 } else {
1346                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1347                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1348                 }
1349         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1350                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1351                                       struct btrfs_extent_data_ref);
1352                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1353         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1354                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1355                                       struct btrfs_shared_data_ref);
1356                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1357 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1358         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1359                 struct btrfs_extent_ref_v0 *ref0;
1360                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1361                                       struct btrfs_extent_ref_v0);
1362                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1363 #endif
1364         } else {
1365                 WARN_ON(1);
1366         }
1367         return num_refs;
1368 }
1369
1370 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1371                                           struct btrfs_root *root,
1372                                           struct btrfs_path *path,
1373                                           u64 bytenr, u64 parent,
1374                                           u64 root_objectid)
1375 {
1376         struct btrfs_key key;
1377         int ret;
1378
1379         key.objectid = bytenr;
1380         if (parent) {
1381                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1382                 key.offset = parent;
1383         } else {
1384                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1385                 key.offset = root_objectid;
1386         }
1387
1388         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1389         if (ret > 0)
1390                 ret = -ENOENT;
1391 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1392         if (ret == -ENOENT && parent) {
1393                 btrfs_release_path(path);
1394                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1395                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1396                 if (ret > 0)
1397                         ret = -ENOENT;
1398         }
1399 #endif
1400         return ret;
1401 }
1402
1403 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1404                                           struct btrfs_root *root,
1405                                           struct btrfs_path *path,
1406                                           u64 bytenr, u64 parent,
1407                                           u64 root_objectid)
1408 {
1409         struct btrfs_key key;
1410         int ret;
1411
1412         key.objectid = bytenr;
1413         if (parent) {
1414                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1415                 key.offset = parent;
1416         } else {
1417                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1418                 key.offset = root_objectid;
1419         }
1420
1421         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1422         btrfs_release_path(path);
1423         return ret;
1424 }
1425
1426 static inline int extent_ref_type(u64 parent, u64 owner)
1427 {
1428         int type;
1429         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1430                 if (parent > 0)
1431                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1432                 else
1433                         type = BTRFS_TREE_BLOCK_REF_KEY;
1434         } else {
1435                 if (parent > 0)
1436                         type = BTRFS_SHARED_DATA_REF_KEY;
1437                 else
1438                         type = BTRFS_EXTENT_DATA_REF_KEY;
1439         }
1440         return type;
1441 }
1442
1443 static int find_next_key(struct btrfs_path *path, int level,
1444                          struct btrfs_key *key)
1445
1446 {
1447         for (; level < BTRFS_MAX_LEVEL; level++) {
1448                 if (!path->nodes[level])
1449                         break;
1450                 if (path->slots[level] + 1 >=
1451                     btrfs_header_nritems(path->nodes[level]))
1452                         continue;
1453                 if (level == 0)
1454                         btrfs_item_key_to_cpu(path->nodes[level], key,
1455                                               path->slots[level] + 1);
1456                 else
1457                         btrfs_node_key_to_cpu(path->nodes[level], key,
1458                                               path->slots[level] + 1);
1459                 return 0;
1460         }
1461         return 1;
1462 }
1463
1464 /*
1465  * look for inline back ref. if back ref is found, *ref_ret is set
1466  * to the address of inline back ref, and 0 is returned.
1467  *
1468  * if back ref isn't found, *ref_ret is set to the address where it
1469  * should be inserted, and -ENOENT is returned.
1470  *
1471  * if insert is true and there are too many inline back refs, the path
1472  * points to the extent item, and -EAGAIN is returned.
1473  *
1474  * NOTE: inline back refs are ordered in the same way that back ref
1475  *       items in the tree are ordered.
1476  */
1477 static noinline_for_stack
1478 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1479                                  struct btrfs_root *root,
1480                                  struct btrfs_path *path,
1481                                  struct btrfs_extent_inline_ref **ref_ret,
1482                                  u64 bytenr, u64 num_bytes,
1483                                  u64 parent, u64 root_objectid,
1484                                  u64 owner, u64 offset, int insert)
1485 {
1486         struct btrfs_key key;
1487         struct extent_buffer *leaf;
1488         struct btrfs_extent_item *ei;
1489         struct btrfs_extent_inline_ref *iref;
1490         u64 flags;
1491         u64 item_size;
1492         unsigned long ptr;
1493         unsigned long end;
1494         int extra_size;
1495         int type;
1496         int want;
1497         int ret;
1498         int err = 0;
1499         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1500                                                  SKINNY_METADATA);
1501
1502         key.objectid = bytenr;
1503         key.type = BTRFS_EXTENT_ITEM_KEY;
1504         key.offset = num_bytes;
1505
1506         want = extent_ref_type(parent, owner);
1507         if (insert) {
1508                 extra_size = btrfs_extent_inline_ref_size(want);
1509                 path->keep_locks = 1;
1510         } else
1511                 extra_size = -1;
1512
1513         /*
1514          * Owner is our parent level, so we can just add one to get the level
1515          * for the block we are interested in.
1516          */
1517         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1518                 key.type = BTRFS_METADATA_ITEM_KEY;
1519                 key.offset = owner;
1520         }
1521
1522 again:
1523         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1524         if (ret < 0) {
1525                 err = ret;
1526                 goto out;
1527         }
1528
1529         /*
1530          * We may be a newly converted file system which still has the old fat
1531          * extent entries for metadata, so try and see if we have one of those.
1532          */
1533         if (ret > 0 && skinny_metadata) {
1534                 skinny_metadata = false;
1535                 if (path->slots[0]) {
1536                         path->slots[0]--;
1537                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1538                                               path->slots[0]);
1539                         if (key.objectid == bytenr &&
1540                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1541                             key.offset == num_bytes)
1542                                 ret = 0;
1543                 }
1544                 if (ret) {
1545                         key.type = BTRFS_EXTENT_ITEM_KEY;
1546                         key.offset = num_bytes;
1547                         btrfs_release_path(path);
1548                         goto again;
1549                 }
1550         }
1551
1552         if (ret && !insert) {
1553                 err = -ENOENT;
1554                 goto out;
1555         } else if (WARN_ON(ret)) {
1556                 err = -EIO;
1557                 goto out;
1558         }
1559
1560         leaf = path->nodes[0];
1561         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1562 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1563         if (item_size < sizeof(*ei)) {
1564                 if (!insert) {
1565                         err = -ENOENT;
1566                         goto out;
1567                 }
1568                 ret = convert_extent_item_v0(trans, root, path, owner,
1569                                              extra_size);
1570                 if (ret < 0) {
1571                         err = ret;
1572                         goto out;
1573                 }
1574                 leaf = path->nodes[0];
1575                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1576         }
1577 #endif
1578         BUG_ON(item_size < sizeof(*ei));
1579
1580         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1581         flags = btrfs_extent_flags(leaf, ei);
1582
1583         ptr = (unsigned long)(ei + 1);
1584         end = (unsigned long)ei + item_size;
1585
1586         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1587                 ptr += sizeof(struct btrfs_tree_block_info);
1588                 BUG_ON(ptr > end);
1589         }
1590
1591         err = -ENOENT;
1592         while (1) {
1593                 if (ptr >= end) {
1594                         WARN_ON(ptr > end);
1595                         break;
1596                 }
1597                 iref = (struct btrfs_extent_inline_ref *)ptr;
1598                 type = btrfs_extent_inline_ref_type(leaf, iref);
1599                 if (want < type)
1600                         break;
1601                 if (want > type) {
1602                         ptr += btrfs_extent_inline_ref_size(type);
1603                         continue;
1604                 }
1605
1606                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1607                         struct btrfs_extent_data_ref *dref;
1608                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1609                         if (match_extent_data_ref(leaf, dref, root_objectid,
1610                                                   owner, offset)) {
1611                                 err = 0;
1612                                 break;
1613                         }
1614                         if (hash_extent_data_ref_item(leaf, dref) <
1615                             hash_extent_data_ref(root_objectid, owner, offset))
1616                                 break;
1617                 } else {
1618                         u64 ref_offset;
1619                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1620                         if (parent > 0) {
1621                                 if (parent == ref_offset) {
1622                                         err = 0;
1623                                         break;
1624                                 }
1625                                 if (ref_offset < parent)
1626                                         break;
1627                         } else {
1628                                 if (root_objectid == ref_offset) {
1629                                         err = 0;
1630                                         break;
1631                                 }
1632                                 if (ref_offset < root_objectid)
1633                                         break;
1634                         }
1635                 }
1636                 ptr += btrfs_extent_inline_ref_size(type);
1637         }
1638         if (err == -ENOENT && insert) {
1639                 if (item_size + extra_size >=
1640                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1641                         err = -EAGAIN;
1642                         goto out;
1643                 }
1644                 /*
1645                  * To add new inline back ref, we have to make sure
1646                  * there is no corresponding back ref item.
1647                  * For simplicity, we just do not add new inline back
1648                  * ref if there is any kind of item for this block
1649                  */
1650                 if (find_next_key(path, 0, &key) == 0 &&
1651                     key.objectid == bytenr &&
1652                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1653                         err = -EAGAIN;
1654                         goto out;
1655                 }
1656         }
1657         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1658 out:
1659         if (insert) {
1660                 path->keep_locks = 0;
1661                 btrfs_unlock_up_safe(path, 1);
1662         }
1663         return err;
1664 }
1665
1666 /*
1667  * helper to add new inline back ref
1668  */
1669 static noinline_for_stack
1670 void setup_inline_extent_backref(struct btrfs_root *root,
1671                                  struct btrfs_path *path,
1672                                  struct btrfs_extent_inline_ref *iref,
1673                                  u64 parent, u64 root_objectid,
1674                                  u64 owner, u64 offset, int refs_to_add,
1675                                  struct btrfs_delayed_extent_op *extent_op)
1676 {
1677         struct extent_buffer *leaf;
1678         struct btrfs_extent_item *ei;
1679         unsigned long ptr;
1680         unsigned long end;
1681         unsigned long item_offset;
1682         u64 refs;
1683         int size;
1684         int type;
1685
1686         leaf = path->nodes[0];
1687         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1688         item_offset = (unsigned long)iref - (unsigned long)ei;
1689
1690         type = extent_ref_type(parent, owner);
1691         size = btrfs_extent_inline_ref_size(type);
1692
1693         btrfs_extend_item(root, path, size);
1694
1695         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1696         refs = btrfs_extent_refs(leaf, ei);
1697         refs += refs_to_add;
1698         btrfs_set_extent_refs(leaf, ei, refs);
1699         if (extent_op)
1700                 __run_delayed_extent_op(extent_op, leaf, ei);
1701
1702         ptr = (unsigned long)ei + item_offset;
1703         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1704         if (ptr < end - size)
1705                 memmove_extent_buffer(leaf, ptr + size, ptr,
1706                                       end - size - ptr);
1707
1708         iref = (struct btrfs_extent_inline_ref *)ptr;
1709         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1710         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1711                 struct btrfs_extent_data_ref *dref;
1712                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1713                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1714                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1715                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1716                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1717         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1718                 struct btrfs_shared_data_ref *sref;
1719                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1720                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1721                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1722         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1723                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1724         } else {
1725                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1726         }
1727         btrfs_mark_buffer_dirty(leaf);
1728 }
1729
1730 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1731                                  struct btrfs_root *root,
1732                                  struct btrfs_path *path,
1733                                  struct btrfs_extent_inline_ref **ref_ret,
1734                                  u64 bytenr, u64 num_bytes, u64 parent,
1735                                  u64 root_objectid, u64 owner, u64 offset)
1736 {
1737         int ret;
1738
1739         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1740                                            bytenr, num_bytes, parent,
1741                                            root_objectid, owner, offset, 0);
1742         if (ret != -ENOENT)
1743                 return ret;
1744
1745         btrfs_release_path(path);
1746         *ref_ret = NULL;
1747
1748         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1749                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1750                                             root_objectid);
1751         } else {
1752                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1753                                              root_objectid, owner, offset);
1754         }
1755         return ret;
1756 }
1757
1758 /*
1759  * helper to update/remove inline back ref
1760  */
1761 static noinline_for_stack
1762 void update_inline_extent_backref(struct btrfs_root *root,
1763                                   struct btrfs_path *path,
1764                                   struct btrfs_extent_inline_ref *iref,
1765                                   int refs_to_mod,
1766                                   struct btrfs_delayed_extent_op *extent_op)
1767 {
1768         struct extent_buffer *leaf;
1769         struct btrfs_extent_item *ei;
1770         struct btrfs_extent_data_ref *dref = NULL;
1771         struct btrfs_shared_data_ref *sref = NULL;
1772         unsigned long ptr;
1773         unsigned long end;
1774         u32 item_size;
1775         int size;
1776         int type;
1777         u64 refs;
1778
1779         leaf = path->nodes[0];
1780         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1781         refs = btrfs_extent_refs(leaf, ei);
1782         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1783         refs += refs_to_mod;
1784         btrfs_set_extent_refs(leaf, ei, refs);
1785         if (extent_op)
1786                 __run_delayed_extent_op(extent_op, leaf, ei);
1787
1788         type = btrfs_extent_inline_ref_type(leaf, iref);
1789
1790         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1791                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1792                 refs = btrfs_extent_data_ref_count(leaf, dref);
1793         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1794                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1795                 refs = btrfs_shared_data_ref_count(leaf, sref);
1796         } else {
1797                 refs = 1;
1798                 BUG_ON(refs_to_mod != -1);
1799         }
1800
1801         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1802         refs += refs_to_mod;
1803
1804         if (refs > 0) {
1805                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1806                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1807                 else
1808                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1809         } else {
1810                 size =  btrfs_extent_inline_ref_size(type);
1811                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1812                 ptr = (unsigned long)iref;
1813                 end = (unsigned long)ei + item_size;
1814                 if (ptr + size < end)
1815                         memmove_extent_buffer(leaf, ptr, ptr + size,
1816                                               end - ptr - size);
1817                 item_size -= size;
1818                 btrfs_truncate_item(root, path, item_size, 1);
1819         }
1820         btrfs_mark_buffer_dirty(leaf);
1821 }
1822
1823 static noinline_for_stack
1824 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1825                                  struct btrfs_root *root,
1826                                  struct btrfs_path *path,
1827                                  u64 bytenr, u64 num_bytes, u64 parent,
1828                                  u64 root_objectid, u64 owner,
1829                                  u64 offset, int refs_to_add,
1830                                  struct btrfs_delayed_extent_op *extent_op)
1831 {
1832         struct btrfs_extent_inline_ref *iref;
1833         int ret;
1834
1835         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1836                                            bytenr, num_bytes, parent,
1837                                            root_objectid, owner, offset, 1);
1838         if (ret == 0) {
1839                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1840                 update_inline_extent_backref(root, path, iref,
1841                                              refs_to_add, extent_op);
1842         } else if (ret == -ENOENT) {
1843                 setup_inline_extent_backref(root, path, iref, parent,
1844                                             root_objectid, owner, offset,
1845                                             refs_to_add, extent_op);
1846                 ret = 0;
1847         }
1848         return ret;
1849 }
1850
1851 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1852                                  struct btrfs_root *root,
1853                                  struct btrfs_path *path,
1854                                  u64 bytenr, u64 parent, u64 root_objectid,
1855                                  u64 owner, u64 offset, int refs_to_add)
1856 {
1857         int ret;
1858         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1859                 BUG_ON(refs_to_add != 1);
1860                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1861                                             parent, root_objectid);
1862         } else {
1863                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1864                                              parent, root_objectid,
1865                                              owner, offset, refs_to_add);
1866         }
1867         return ret;
1868 }
1869
1870 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1871                                  struct btrfs_root *root,
1872                                  struct btrfs_path *path,
1873                                  struct btrfs_extent_inline_ref *iref,
1874                                  int refs_to_drop, int is_data)
1875 {
1876         int ret = 0;
1877
1878         BUG_ON(!is_data && refs_to_drop != 1);
1879         if (iref) {
1880                 update_inline_extent_backref(root, path, iref,
1881                                              -refs_to_drop, NULL);
1882         } else if (is_data) {
1883                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1884         } else {
1885                 ret = btrfs_del_item(trans, root, path);
1886         }
1887         return ret;
1888 }
1889
1890 static int btrfs_issue_discard(struct block_device *bdev,
1891                                 u64 start, u64 len)
1892 {
1893         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1894 }
1895
1896 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1897                                 u64 num_bytes, u64 *actual_bytes)
1898 {
1899         int ret;
1900         u64 discarded_bytes = 0;
1901         struct btrfs_bio *bbio = NULL;
1902
1903
1904         /* Tell the block device(s) that the sectors can be discarded */
1905         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1906                               bytenr, &num_bytes, &bbio, 0);
1907         /* Error condition is -ENOMEM */
1908         if (!ret) {
1909                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1910                 int i;
1911
1912
1913                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1914                         if (!stripe->dev->can_discard)
1915                                 continue;
1916
1917                         ret = btrfs_issue_discard(stripe->dev->bdev,
1918                                                   stripe->physical,
1919                                                   stripe->length);
1920                         if (!ret)
1921                                 discarded_bytes += stripe->length;
1922                         else if (ret != -EOPNOTSUPP)
1923                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1924
1925                         /*
1926                          * Just in case we get back EOPNOTSUPP for some reason,
1927                          * just ignore the return value so we don't screw up
1928                          * people calling discard_extent.
1929                          */
1930                         ret = 0;
1931                 }
1932                 kfree(bbio);
1933         }
1934
1935         if (actual_bytes)
1936                 *actual_bytes = discarded_bytes;
1937
1938
1939         if (ret == -EOPNOTSUPP)
1940                 ret = 0;
1941         return ret;
1942 }
1943
1944 /* Can return -ENOMEM */
1945 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1946                          struct btrfs_root *root,
1947                          u64 bytenr, u64 num_bytes, u64 parent,
1948                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1949 {
1950         int ret;
1951         struct btrfs_fs_info *fs_info = root->fs_info;
1952
1953         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1954                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1955
1956         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1957                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1958                                         num_bytes,
1959                                         parent, root_objectid, (int)owner,
1960                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1961         } else {
1962                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1963                                         num_bytes,
1964                                         parent, root_objectid, owner, offset,
1965                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1966         }
1967         return ret;
1968 }
1969
1970 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1971                                   struct btrfs_root *root,
1972                                   u64 bytenr, u64 num_bytes,
1973                                   u64 parent, u64 root_objectid,
1974                                   u64 owner, u64 offset, int refs_to_add,
1975                                   struct btrfs_delayed_extent_op *extent_op)
1976 {
1977         struct btrfs_path *path;
1978         struct extent_buffer *leaf;
1979         struct btrfs_extent_item *item;
1980         u64 refs;
1981         int ret;
1982
1983         path = btrfs_alloc_path();
1984         if (!path)
1985                 return -ENOMEM;
1986
1987         path->reada = 1;
1988         path->leave_spinning = 1;
1989         /* this will setup the path even if it fails to insert the back ref */
1990         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1991                                            path, bytenr, num_bytes, parent,
1992                                            root_objectid, owner, offset,
1993                                            refs_to_add, extent_op);
1994         if (ret != -EAGAIN)
1995                 goto out;
1996
1997         leaf = path->nodes[0];
1998         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1999         refs = btrfs_extent_refs(leaf, item);
2000         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2001         if (extent_op)
2002                 __run_delayed_extent_op(extent_op, leaf, item);
2003
2004         btrfs_mark_buffer_dirty(leaf);
2005         btrfs_release_path(path);
2006
2007         path->reada = 1;
2008         path->leave_spinning = 1;
2009
2010         /* now insert the actual backref */
2011         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2012                                     path, bytenr, parent, root_objectid,
2013                                     owner, offset, refs_to_add);
2014         if (ret)
2015                 btrfs_abort_transaction(trans, root, ret);
2016 out:
2017         btrfs_free_path(path);
2018         return ret;
2019 }
2020
2021 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2022                                 struct btrfs_root *root,
2023                                 struct btrfs_delayed_ref_node *node,
2024                                 struct btrfs_delayed_extent_op *extent_op,
2025                                 int insert_reserved)
2026 {
2027         int ret = 0;
2028         struct btrfs_delayed_data_ref *ref;
2029         struct btrfs_key ins;
2030         u64 parent = 0;
2031         u64 ref_root = 0;
2032         u64 flags = 0;
2033
2034         ins.objectid = node->bytenr;
2035         ins.offset = node->num_bytes;
2036         ins.type = BTRFS_EXTENT_ITEM_KEY;
2037
2038         ref = btrfs_delayed_node_to_data_ref(node);
2039         trace_run_delayed_data_ref(node, ref, node->action);
2040
2041         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2042                 parent = ref->parent;
2043         else
2044                 ref_root = ref->root;
2045
2046         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2047                 if (extent_op)
2048                         flags |= extent_op->flags_to_set;
2049                 ret = alloc_reserved_file_extent(trans, root,
2050                                                  parent, ref_root, flags,
2051                                                  ref->objectid, ref->offset,
2052                                                  &ins, node->ref_mod);
2053         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2054                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2055                                              node->num_bytes, parent,
2056                                              ref_root, ref->objectid,
2057                                              ref->offset, node->ref_mod,
2058                                              extent_op);
2059         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2060                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2061                                           node->num_bytes, parent,
2062                                           ref_root, ref->objectid,
2063                                           ref->offset, node->ref_mod,
2064                                           extent_op);
2065         } else {
2066                 BUG();
2067         }
2068         return ret;
2069 }
2070
2071 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2072                                     struct extent_buffer *leaf,
2073                                     struct btrfs_extent_item *ei)
2074 {
2075         u64 flags = btrfs_extent_flags(leaf, ei);
2076         if (extent_op->update_flags) {
2077                 flags |= extent_op->flags_to_set;
2078                 btrfs_set_extent_flags(leaf, ei, flags);
2079         }
2080
2081         if (extent_op->update_key) {
2082                 struct btrfs_tree_block_info *bi;
2083                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2084                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2085                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2086         }
2087 }
2088
2089 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2090                                  struct btrfs_root *root,
2091                                  struct btrfs_delayed_ref_node *node,
2092                                  struct btrfs_delayed_extent_op *extent_op)
2093 {
2094         struct btrfs_key key;
2095         struct btrfs_path *path;
2096         struct btrfs_extent_item *ei;
2097         struct extent_buffer *leaf;
2098         u32 item_size;
2099         int ret;
2100         int err = 0;
2101         int metadata = !extent_op->is_data;
2102
2103         if (trans->aborted)
2104                 return 0;
2105
2106         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2107                 metadata = 0;
2108
2109         path = btrfs_alloc_path();
2110         if (!path)
2111                 return -ENOMEM;
2112
2113         key.objectid = node->bytenr;
2114
2115         if (metadata) {
2116                 key.type = BTRFS_METADATA_ITEM_KEY;
2117                 key.offset = extent_op->level;
2118         } else {
2119                 key.type = BTRFS_EXTENT_ITEM_KEY;
2120                 key.offset = node->num_bytes;
2121         }
2122
2123 again:
2124         path->reada = 1;
2125         path->leave_spinning = 1;
2126         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2127                                 path, 0, 1);
2128         if (ret < 0) {
2129                 err = ret;
2130                 goto out;
2131         }
2132         if (ret > 0) {
2133                 if (metadata) {
2134                         if (path->slots[0] > 0) {
2135                                 path->slots[0]--;
2136                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2137                                                       path->slots[0]);
2138                                 if (key.objectid == node->bytenr &&
2139                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2140                                     key.offset == node->num_bytes)
2141                                         ret = 0;
2142                         }
2143                         if (ret > 0) {
2144                                 btrfs_release_path(path);
2145                                 metadata = 0;
2146
2147                                 key.objectid = node->bytenr;
2148                                 key.offset = node->num_bytes;
2149                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2150                                 goto again;
2151                         }
2152                 } else {
2153                         err = -EIO;
2154                         goto out;
2155                 }
2156         }
2157
2158         leaf = path->nodes[0];
2159         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2160 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2161         if (item_size < sizeof(*ei)) {
2162                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2163                                              path, (u64)-1, 0);
2164                 if (ret < 0) {
2165                         err = ret;
2166                         goto out;
2167                 }
2168                 leaf = path->nodes[0];
2169                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2170         }
2171 #endif
2172         BUG_ON(item_size < sizeof(*ei));
2173         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2174         __run_delayed_extent_op(extent_op, leaf, ei);
2175
2176         btrfs_mark_buffer_dirty(leaf);
2177 out:
2178         btrfs_free_path(path);
2179         return err;
2180 }
2181
2182 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2183                                 struct btrfs_root *root,
2184                                 struct btrfs_delayed_ref_node *node,
2185                                 struct btrfs_delayed_extent_op *extent_op,
2186                                 int insert_reserved)
2187 {
2188         int ret = 0;
2189         struct btrfs_delayed_tree_ref *ref;
2190         struct btrfs_key ins;
2191         u64 parent = 0;
2192         u64 ref_root = 0;
2193         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2194                                                  SKINNY_METADATA);
2195
2196         ref = btrfs_delayed_node_to_tree_ref(node);
2197         trace_run_delayed_tree_ref(node, ref, node->action);
2198
2199         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2200                 parent = ref->parent;
2201         else
2202                 ref_root = ref->root;
2203
2204         ins.objectid = node->bytenr;
2205         if (skinny_metadata) {
2206                 ins.offset = ref->level;
2207                 ins.type = BTRFS_METADATA_ITEM_KEY;
2208         } else {
2209                 ins.offset = node->num_bytes;
2210                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2211         }
2212
2213         BUG_ON(node->ref_mod != 1);
2214         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2215                 BUG_ON(!extent_op || !extent_op->update_flags);
2216                 ret = alloc_reserved_tree_block(trans, root,
2217                                                 parent, ref_root,
2218                                                 extent_op->flags_to_set,
2219                                                 &extent_op->key,
2220                                                 ref->level, &ins);
2221         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2222                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2223                                              node->num_bytes, parent, ref_root,
2224                                              ref->level, 0, 1, extent_op);
2225         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2226                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2227                                           node->num_bytes, parent, ref_root,
2228                                           ref->level, 0, 1, extent_op);
2229         } else {
2230                 BUG();
2231         }
2232         return ret;
2233 }
2234
2235 /* helper function to actually process a single delayed ref entry */
2236 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2237                                struct btrfs_root *root,
2238                                struct btrfs_delayed_ref_node *node,
2239                                struct btrfs_delayed_extent_op *extent_op,
2240                                int insert_reserved)
2241 {
2242         int ret = 0;
2243
2244         if (trans->aborted) {
2245                 if (insert_reserved)
2246                         btrfs_pin_extent(root, node->bytenr,
2247                                          node->num_bytes, 1);
2248                 return 0;
2249         }
2250
2251         if (btrfs_delayed_ref_is_head(node)) {
2252                 struct btrfs_delayed_ref_head *head;
2253                 /*
2254                  * we've hit the end of the chain and we were supposed
2255                  * to insert this extent into the tree.  But, it got
2256                  * deleted before we ever needed to insert it, so all
2257                  * we have to do is clean up the accounting
2258                  */
2259                 BUG_ON(extent_op);
2260                 head = btrfs_delayed_node_to_head(node);
2261                 trace_run_delayed_ref_head(node, head, node->action);
2262
2263                 if (insert_reserved) {
2264                         btrfs_pin_extent(root, node->bytenr,
2265                                          node->num_bytes, 1);
2266                         if (head->is_data) {
2267                                 ret = btrfs_del_csums(trans, root,
2268                                                       node->bytenr,
2269                                                       node->num_bytes);
2270                         }
2271                 }
2272                 return ret;
2273         }
2274
2275         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2276             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2277                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2278                                            insert_reserved);
2279         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2280                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2281                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2282                                            insert_reserved);
2283         else
2284                 BUG();
2285         return ret;
2286 }
2287
2288 static noinline struct btrfs_delayed_ref_node *
2289 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2290 {
2291         struct rb_node *node;
2292         struct btrfs_delayed_ref_node *ref, *last = NULL;;
2293
2294         /*
2295          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2296          * this prevents ref count from going down to zero when
2297          * there still are pending delayed ref.
2298          */
2299         node = rb_first(&head->ref_root);
2300         while (node) {
2301                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2302                                 rb_node);
2303                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2304                         return ref;
2305                 else if (last == NULL)
2306                         last = ref;
2307                 node = rb_next(node);
2308         }
2309         return last;
2310 }
2311
2312 /*
2313  * Returns 0 on success or if called with an already aborted transaction.
2314  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2315  */
2316 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2317                                              struct btrfs_root *root,
2318                                              unsigned long nr)
2319 {
2320         struct btrfs_delayed_ref_root *delayed_refs;
2321         struct btrfs_delayed_ref_node *ref;
2322         struct btrfs_delayed_ref_head *locked_ref = NULL;
2323         struct btrfs_delayed_extent_op *extent_op;
2324         struct btrfs_fs_info *fs_info = root->fs_info;
2325         int ret;
2326         unsigned long count = 0;
2327         int must_insert_reserved = 0;
2328
2329         delayed_refs = &trans->transaction->delayed_refs;
2330         while (1) {
2331                 if (!locked_ref) {
2332                         if (count >= nr)
2333                                 break;
2334
2335                         spin_lock(&delayed_refs->lock);
2336                         locked_ref = btrfs_select_ref_head(trans);
2337                         if (!locked_ref) {
2338                                 spin_unlock(&delayed_refs->lock);
2339                                 break;
2340                         }
2341
2342                         /* grab the lock that says we are going to process
2343                          * all the refs for this head */
2344                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2345                         spin_unlock(&delayed_refs->lock);
2346                         /*
2347                          * we may have dropped the spin lock to get the head
2348                          * mutex lock, and that might have given someone else
2349                          * time to free the head.  If that's true, it has been
2350                          * removed from our list and we can move on.
2351                          */
2352                         if (ret == -EAGAIN) {
2353                                 locked_ref = NULL;
2354                                 count++;
2355                                 continue;
2356                         }
2357                 }
2358
2359                 /*
2360                  * We need to try and merge add/drops of the same ref since we
2361                  * can run into issues with relocate dropping the implicit ref
2362                  * and then it being added back again before the drop can
2363                  * finish.  If we merged anything we need to re-loop so we can
2364                  * get a good ref.
2365                  */
2366                 spin_lock(&locked_ref->lock);
2367                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2368                                          locked_ref);
2369
2370                 /*
2371                  * locked_ref is the head node, so we have to go one
2372                  * node back for any delayed ref updates
2373                  */
2374                 ref = select_delayed_ref(locked_ref);
2375
2376                 if (ref && ref->seq &&
2377                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2378                         spin_unlock(&locked_ref->lock);
2379                         btrfs_delayed_ref_unlock(locked_ref);
2380                         spin_lock(&delayed_refs->lock);
2381                         locked_ref->processing = 0;
2382                         delayed_refs->num_heads_ready++;
2383                         spin_unlock(&delayed_refs->lock);
2384                         locked_ref = NULL;
2385                         cond_resched();
2386                         continue;
2387                 }
2388
2389                 /*
2390                  * record the must insert reserved flag before we
2391                  * drop the spin lock.
2392                  */
2393                 must_insert_reserved = locked_ref->must_insert_reserved;
2394                 locked_ref->must_insert_reserved = 0;
2395
2396                 extent_op = locked_ref->extent_op;
2397                 locked_ref->extent_op = NULL;
2398
2399                 if (!ref) {
2400
2401
2402                         /* All delayed refs have been processed, Go ahead
2403                          * and send the head node to run_one_delayed_ref,
2404                          * so that any accounting fixes can happen
2405                          */
2406                         ref = &locked_ref->node;
2407
2408                         if (extent_op && must_insert_reserved) {
2409                                 btrfs_free_delayed_extent_op(extent_op);
2410                                 extent_op = NULL;
2411                         }
2412
2413                         if (extent_op) {
2414                                 spin_unlock(&locked_ref->lock);
2415                                 ret = run_delayed_extent_op(trans, root,
2416                                                             ref, extent_op);
2417                                 btrfs_free_delayed_extent_op(extent_op);
2418
2419                                 if (ret) {
2420                                         /*
2421                                          * Need to reset must_insert_reserved if
2422                                          * there was an error so the abort stuff
2423                                          * can cleanup the reserved space
2424                                          * properly.
2425                                          */
2426                                         if (must_insert_reserved)
2427                                                 locked_ref->must_insert_reserved = 1;
2428                                         locked_ref->processing = 0;
2429                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2430                                         btrfs_delayed_ref_unlock(locked_ref);
2431                                         return ret;
2432                                 }
2433                                 continue;
2434                         }
2435
2436                         /*
2437                          * Need to drop our head ref lock and re-aqcuire the
2438                          * delayed ref lock and then re-check to make sure
2439                          * nobody got added.
2440                          */
2441                         spin_unlock(&locked_ref->lock);
2442                         spin_lock(&delayed_refs->lock);
2443                         spin_lock(&locked_ref->lock);
2444                         if (rb_first(&locked_ref->ref_root)) {
2445                                 spin_unlock(&locked_ref->lock);
2446                                 spin_unlock(&delayed_refs->lock);
2447                                 continue;
2448                         }
2449                         ref->in_tree = 0;
2450                         delayed_refs->num_heads--;
2451                         rb_erase(&locked_ref->href_node,
2452                                  &delayed_refs->href_root);
2453                         spin_unlock(&delayed_refs->lock);
2454                 } else {
2455                         ref->in_tree = 0;
2456                         rb_erase(&ref->rb_node, &locked_ref->ref_root);
2457                 }
2458                 atomic_dec(&delayed_refs->num_entries);
2459
2460                 if (!btrfs_delayed_ref_is_head(ref)) {
2461                         /*
2462                          * when we play the delayed ref, also correct the
2463                          * ref_mod on head
2464                          */
2465                         switch (ref->action) {
2466                         case BTRFS_ADD_DELAYED_REF:
2467                         case BTRFS_ADD_DELAYED_EXTENT:
2468                                 locked_ref->node.ref_mod -= ref->ref_mod;
2469                                 break;
2470                         case BTRFS_DROP_DELAYED_REF:
2471                                 locked_ref->node.ref_mod += ref->ref_mod;
2472                                 break;
2473                         default:
2474                                 WARN_ON(1);
2475                         }
2476                 }
2477                 spin_unlock(&locked_ref->lock);
2478
2479                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2480                                           must_insert_reserved);
2481
2482                 btrfs_free_delayed_extent_op(extent_op);
2483                 if (ret) {
2484                         locked_ref->processing = 0;
2485                         btrfs_delayed_ref_unlock(locked_ref);
2486                         btrfs_put_delayed_ref(ref);
2487                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2488                         return ret;
2489                 }
2490
2491                 /*
2492                  * If this node is a head, that means all the refs in this head
2493                  * have been dealt with, and we will pick the next head to deal
2494                  * with, so we must unlock the head and drop it from the cluster
2495                  * list before we release it.
2496                  */
2497                 if (btrfs_delayed_ref_is_head(ref)) {
2498                         btrfs_delayed_ref_unlock(locked_ref);
2499                         locked_ref = NULL;
2500                 }
2501                 btrfs_put_delayed_ref(ref);
2502                 count++;
2503                 cond_resched();
2504         }
2505         return 0;
2506 }
2507
2508 #ifdef SCRAMBLE_DELAYED_REFS
2509 /*
2510  * Normally delayed refs get processed in ascending bytenr order. This
2511  * correlates in most cases to the order added. To expose dependencies on this
2512  * order, we start to process the tree in the middle instead of the beginning
2513  */
2514 static u64 find_middle(struct rb_root *root)
2515 {
2516         struct rb_node *n = root->rb_node;
2517         struct btrfs_delayed_ref_node *entry;
2518         int alt = 1;
2519         u64 middle;
2520         u64 first = 0, last = 0;
2521
2522         n = rb_first(root);
2523         if (n) {
2524                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2525                 first = entry->bytenr;
2526         }
2527         n = rb_last(root);
2528         if (n) {
2529                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2530                 last = entry->bytenr;
2531         }
2532         n = root->rb_node;
2533
2534         while (n) {
2535                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2536                 WARN_ON(!entry->in_tree);
2537
2538                 middle = entry->bytenr;
2539
2540                 if (alt)
2541                         n = n->rb_left;
2542                 else
2543                         n = n->rb_right;
2544
2545                 alt = 1 - alt;
2546         }
2547         return middle;
2548 }
2549 #endif
2550
2551 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2552                                          struct btrfs_fs_info *fs_info)
2553 {
2554         struct qgroup_update *qgroup_update;
2555         int ret = 0;
2556
2557         if (list_empty(&trans->qgroup_ref_list) !=
2558             !trans->delayed_ref_elem.seq) {
2559                 /* list without seq or seq without list */
2560                 btrfs_err(fs_info,
2561                         "qgroup accounting update error, list is%s empty, seq is %#x.%x",
2562                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2563                         (u32)(trans->delayed_ref_elem.seq >> 32),
2564                         (u32)trans->delayed_ref_elem.seq);
2565                 BUG();
2566         }
2567
2568         if (!trans->delayed_ref_elem.seq)
2569                 return 0;
2570
2571         while (!list_empty(&trans->qgroup_ref_list)) {
2572                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2573                                                  struct qgroup_update, list);
2574                 list_del(&qgroup_update->list);
2575                 if (!ret)
2576                         ret = btrfs_qgroup_account_ref(
2577                                         trans, fs_info, qgroup_update->node,
2578                                         qgroup_update->extent_op);
2579                 kfree(qgroup_update);
2580         }
2581
2582         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2583
2584         return ret;
2585 }
2586
2587 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2588 {
2589         u64 num_bytes;
2590
2591         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2592                              sizeof(struct btrfs_extent_inline_ref));
2593         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2594                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2595
2596         /*
2597          * We don't ever fill up leaves all the way so multiply by 2 just to be
2598          * closer to what we're really going to want to ouse.
2599          */
2600         return div64_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2601 }
2602
2603 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2604                                        struct btrfs_root *root)
2605 {
2606         struct btrfs_block_rsv *global_rsv;
2607         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2608         u64 num_bytes;
2609         int ret = 0;
2610
2611         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2612         num_heads = heads_to_leaves(root, num_heads);
2613         if (num_heads > 1)
2614                 num_bytes += (num_heads - 1) * root->leafsize;
2615         num_bytes <<= 1;
2616         global_rsv = &root->fs_info->global_block_rsv;
2617
2618         /*
2619          * If we can't allocate any more chunks lets make sure we have _lots_ of
2620          * wiggle room since running delayed refs can create more delayed refs.
2621          */
2622         if (global_rsv->space_info->full)
2623                 num_bytes <<= 1;
2624
2625         spin_lock(&global_rsv->lock);
2626         if (global_rsv->reserved <= num_bytes)
2627                 ret = 1;
2628         spin_unlock(&global_rsv->lock);
2629         return ret;
2630 }
2631
2632 /*
2633  * this starts processing the delayed reference count updates and
2634  * extent insertions we have queued up so far.  count can be
2635  * 0, which means to process everything in the tree at the start
2636  * of the run (but not newly added entries), or it can be some target
2637  * number you'd like to process.
2638  *
2639  * Returns 0 on success or if called with an aborted transaction
2640  * Returns <0 on error and aborts the transaction
2641  */
2642 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2643                            struct btrfs_root *root, unsigned long count)
2644 {
2645         struct rb_node *node;
2646         struct btrfs_delayed_ref_root *delayed_refs;
2647         struct btrfs_delayed_ref_head *head;
2648         int ret;
2649         int run_all = count == (unsigned long)-1;
2650         int run_most = 0;
2651
2652         /* We'll clean this up in btrfs_cleanup_transaction */
2653         if (trans->aborted)
2654                 return 0;
2655
2656         if (root == root->fs_info->extent_root)
2657                 root = root->fs_info->tree_root;
2658
2659         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2660
2661         delayed_refs = &trans->transaction->delayed_refs;
2662         if (count == 0) {
2663                 count = atomic_read(&delayed_refs->num_entries) * 2;
2664                 run_most = 1;
2665         }
2666
2667 again:
2668 #ifdef SCRAMBLE_DELAYED_REFS
2669         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2670 #endif
2671         ret = __btrfs_run_delayed_refs(trans, root, count);
2672         if (ret < 0) {
2673                 btrfs_abort_transaction(trans, root, ret);
2674                 return ret;
2675         }
2676
2677         if (run_all) {
2678                 if (!list_empty(&trans->new_bgs))
2679                         btrfs_create_pending_block_groups(trans, root);
2680
2681                 spin_lock(&delayed_refs->lock);
2682                 node = rb_first(&delayed_refs->href_root);
2683                 if (!node) {
2684                         spin_unlock(&delayed_refs->lock);
2685                         goto out;
2686                 }
2687                 count = (unsigned long)-1;
2688
2689                 while (node) {
2690                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2691                                         href_node);
2692                         if (btrfs_delayed_ref_is_head(&head->node)) {
2693                                 struct btrfs_delayed_ref_node *ref;
2694
2695                                 ref = &head->node;
2696                                 atomic_inc(&ref->refs);
2697
2698                                 spin_unlock(&delayed_refs->lock);
2699                                 /*
2700                                  * Mutex was contended, block until it's
2701                                  * released and try again
2702                                  */
2703                                 mutex_lock(&head->mutex);
2704                                 mutex_unlock(&head->mutex);
2705
2706                                 btrfs_put_delayed_ref(ref);
2707                                 cond_resched();
2708                                 goto again;
2709                         } else {
2710                                 WARN_ON(1);
2711                         }
2712                         node = rb_next(node);
2713                 }
2714                 spin_unlock(&delayed_refs->lock);
2715                 cond_resched();
2716                 goto again;
2717         }
2718 out:
2719         assert_qgroups_uptodate(trans);
2720         return 0;
2721 }
2722
2723 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2724                                 struct btrfs_root *root,
2725                                 u64 bytenr, u64 num_bytes, u64 flags,
2726                                 int level, int is_data)
2727 {
2728         struct btrfs_delayed_extent_op *extent_op;
2729         int ret;
2730
2731         extent_op = btrfs_alloc_delayed_extent_op();
2732         if (!extent_op)
2733                 return -ENOMEM;
2734
2735         extent_op->flags_to_set = flags;
2736         extent_op->update_flags = 1;
2737         extent_op->update_key = 0;
2738         extent_op->is_data = is_data ? 1 : 0;
2739         extent_op->level = level;
2740
2741         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2742                                           num_bytes, extent_op);
2743         if (ret)
2744                 btrfs_free_delayed_extent_op(extent_op);
2745         return ret;
2746 }
2747
2748 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2749                                       struct btrfs_root *root,
2750                                       struct btrfs_path *path,
2751                                       u64 objectid, u64 offset, u64 bytenr)
2752 {
2753         struct btrfs_delayed_ref_head *head;
2754         struct btrfs_delayed_ref_node *ref;
2755         struct btrfs_delayed_data_ref *data_ref;
2756         struct btrfs_delayed_ref_root *delayed_refs;
2757         struct rb_node *node;
2758         int ret = 0;
2759
2760         delayed_refs = &trans->transaction->delayed_refs;
2761         spin_lock(&delayed_refs->lock);
2762         head = btrfs_find_delayed_ref_head(trans, bytenr);
2763         if (!head) {
2764                 spin_unlock(&delayed_refs->lock);
2765                 return 0;
2766         }
2767
2768         if (!mutex_trylock(&head->mutex)) {
2769                 atomic_inc(&head->node.refs);
2770                 spin_unlock(&delayed_refs->lock);
2771
2772                 btrfs_release_path(path);
2773
2774                 /*
2775                  * Mutex was contended, block until it's released and let
2776                  * caller try again
2777                  */
2778                 mutex_lock(&head->mutex);
2779                 mutex_unlock(&head->mutex);
2780                 btrfs_put_delayed_ref(&head->node);
2781                 return -EAGAIN;
2782         }
2783         spin_unlock(&delayed_refs->lock);
2784
2785         spin_lock(&head->lock);
2786         node = rb_first(&head->ref_root);
2787         while (node) {
2788                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2789                 node = rb_next(node);
2790
2791                 /* If it's a shared ref we know a cross reference exists */
2792                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2793                         ret = 1;
2794                         break;
2795                 }
2796
2797                 data_ref = btrfs_delayed_node_to_data_ref(ref);
2798
2799                 /*
2800                  * If our ref doesn't match the one we're currently looking at
2801                  * then we have a cross reference.
2802                  */
2803                 if (data_ref->root != root->root_key.objectid ||
2804                     data_ref->objectid != objectid ||
2805                     data_ref->offset != offset) {
2806                         ret = 1;
2807                         break;
2808                 }
2809         }
2810         spin_unlock(&head->lock);
2811         mutex_unlock(&head->mutex);
2812         return ret;
2813 }
2814
2815 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2816                                         struct btrfs_root *root,
2817                                         struct btrfs_path *path,
2818                                         u64 objectid, u64 offset, u64 bytenr)
2819 {
2820         struct btrfs_root *extent_root = root->fs_info->extent_root;
2821         struct extent_buffer *leaf;
2822         struct btrfs_extent_data_ref *ref;
2823         struct btrfs_extent_inline_ref *iref;
2824         struct btrfs_extent_item *ei;
2825         struct btrfs_key key;
2826         u32 item_size;
2827         int ret;
2828
2829         key.objectid = bytenr;
2830         key.offset = (u64)-1;
2831         key.type = BTRFS_EXTENT_ITEM_KEY;
2832
2833         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2834         if (ret < 0)
2835                 goto out;
2836         BUG_ON(ret == 0); /* Corruption */
2837
2838         ret = -ENOENT;
2839         if (path->slots[0] == 0)
2840                 goto out;
2841
2842         path->slots[0]--;
2843         leaf = path->nodes[0];
2844         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2845
2846         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2847                 goto out;
2848
2849         ret = 1;
2850         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2851 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2852         if (item_size < sizeof(*ei)) {
2853                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2854                 goto out;
2855         }
2856 #endif
2857         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2858
2859         if (item_size != sizeof(*ei) +
2860             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2861                 goto out;
2862
2863         if (btrfs_extent_generation(leaf, ei) <=
2864             btrfs_root_last_snapshot(&root->root_item))
2865                 goto out;
2866
2867         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2868         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2869             BTRFS_EXTENT_DATA_REF_KEY)
2870                 goto out;
2871
2872         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2873         if (btrfs_extent_refs(leaf, ei) !=
2874             btrfs_extent_data_ref_count(leaf, ref) ||
2875             btrfs_extent_data_ref_root(leaf, ref) !=
2876             root->root_key.objectid ||
2877             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2878             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2879                 goto out;
2880
2881         ret = 0;
2882 out:
2883         return ret;
2884 }
2885
2886 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2887                           struct btrfs_root *root,
2888                           u64 objectid, u64 offset, u64 bytenr)
2889 {
2890         struct btrfs_path *path;
2891         int ret;
2892         int ret2;
2893
2894         path = btrfs_alloc_path();
2895         if (!path)
2896                 return -ENOENT;
2897
2898         do {
2899                 ret = check_committed_ref(trans, root, path, objectid,
2900                                           offset, bytenr);
2901                 if (ret && ret != -ENOENT)
2902                         goto out;
2903
2904                 ret2 = check_delayed_ref(trans, root, path, objectid,
2905                                          offset, bytenr);
2906         } while (ret2 == -EAGAIN);
2907
2908         if (ret2 && ret2 != -ENOENT) {
2909                 ret = ret2;
2910                 goto out;
2911         }
2912
2913         if (ret != -ENOENT || ret2 != -ENOENT)
2914                 ret = 0;
2915 out:
2916         btrfs_free_path(path);
2917         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2918                 WARN_ON(ret > 0);
2919         return ret;
2920 }
2921
2922 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2923                            struct btrfs_root *root,
2924                            struct extent_buffer *buf,
2925                            int full_backref, int inc, int for_cow)
2926 {
2927         u64 bytenr;
2928         u64 num_bytes;
2929         u64 parent;
2930         u64 ref_root;
2931         u32 nritems;
2932         struct btrfs_key key;
2933         struct btrfs_file_extent_item *fi;
2934         int i;
2935         int level;
2936         int ret = 0;
2937         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2938                             u64, u64, u64, u64, u64, u64, int);
2939
2940         ref_root = btrfs_header_owner(buf);
2941         nritems = btrfs_header_nritems(buf);
2942         level = btrfs_header_level(buf);
2943
2944         if (!root->ref_cows && level == 0)
2945                 return 0;
2946
2947         if (inc)
2948                 process_func = btrfs_inc_extent_ref;
2949         else
2950                 process_func = btrfs_free_extent;
2951
2952         if (full_backref)
2953                 parent = buf->start;
2954         else
2955                 parent = 0;
2956
2957         for (i = 0; i < nritems; i++) {
2958                 if (level == 0) {
2959                         btrfs_item_key_to_cpu(buf, &key, i);
2960                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2961                                 continue;
2962                         fi = btrfs_item_ptr(buf, i,
2963                                             struct btrfs_file_extent_item);
2964                         if (btrfs_file_extent_type(buf, fi) ==
2965                             BTRFS_FILE_EXTENT_INLINE)
2966                                 continue;
2967                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2968                         if (bytenr == 0)
2969                                 continue;
2970
2971                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2972                         key.offset -= btrfs_file_extent_offset(buf, fi);
2973                         ret = process_func(trans, root, bytenr, num_bytes,
2974                                            parent, ref_root, key.objectid,
2975                                            key.offset, for_cow);
2976                         if (ret)
2977                                 goto fail;
2978                 } else {
2979                         bytenr = btrfs_node_blockptr(buf, i);
2980                         num_bytes = btrfs_level_size(root, level - 1);
2981                         ret = process_func(trans, root, bytenr, num_bytes,
2982                                            parent, ref_root, level - 1, 0,
2983                                            for_cow);
2984                         if (ret)
2985                                 goto fail;
2986                 }
2987         }
2988         return 0;
2989 fail:
2990         return ret;
2991 }
2992
2993 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2994                   struct extent_buffer *buf, int full_backref, int for_cow)
2995 {
2996         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
2997 }
2998
2999 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3000                   struct extent_buffer *buf, int full_backref, int for_cow)
3001 {
3002         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
3003 }
3004
3005 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3006                                  struct btrfs_root *root,
3007                                  struct btrfs_path *path,
3008                                  struct btrfs_block_group_cache *cache)
3009 {
3010         int ret;
3011         struct btrfs_root *extent_root = root->fs_info->extent_root;
3012         unsigned long bi;
3013         struct extent_buffer *leaf;
3014
3015         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3016         if (ret < 0)
3017                 goto fail;
3018         BUG_ON(ret); /* Corruption */
3019
3020         leaf = path->nodes[0];
3021         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3022         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3023         btrfs_mark_buffer_dirty(leaf);
3024         btrfs_release_path(path);
3025 fail:
3026         if (ret) {
3027                 btrfs_abort_transaction(trans, root, ret);
3028                 return ret;
3029         }
3030         return 0;
3031
3032 }
3033
3034 static struct btrfs_block_group_cache *
3035 next_block_group(struct btrfs_root *root,
3036                  struct btrfs_block_group_cache *cache)
3037 {
3038         struct rb_node *node;
3039         spin_lock(&root->fs_info->block_group_cache_lock);
3040         node = rb_next(&cache->cache_node);
3041         btrfs_put_block_group(cache);
3042         if (node) {
3043                 cache = rb_entry(node, struct btrfs_block_group_cache,
3044                                  cache_node);
3045                 btrfs_get_block_group(cache);
3046         } else
3047                 cache = NULL;
3048         spin_unlock(&root->fs_info->block_group_cache_lock);
3049         return cache;
3050 }
3051
3052 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3053                             struct btrfs_trans_handle *trans,
3054                             struct btrfs_path *path)
3055 {
3056         struct btrfs_root *root = block_group->fs_info->tree_root;
3057         struct inode *inode = NULL;
3058         u64 alloc_hint = 0;
3059         int dcs = BTRFS_DC_ERROR;
3060         int num_pages = 0;
3061         int retries = 0;
3062         int ret = 0;
3063
3064         /*
3065          * If this block group is smaller than 100 megs don't bother caching the
3066          * block group.
3067          */
3068         if (block_group->key.offset < (100 * 1024 * 1024)) {
3069                 spin_lock(&block_group->lock);
3070                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3071                 spin_unlock(&block_group->lock);
3072                 return 0;
3073         }
3074
3075 again:
3076         inode = lookup_free_space_inode(root, block_group, path);
3077         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3078                 ret = PTR_ERR(inode);
3079                 btrfs_release_path(path);
3080                 goto out;
3081         }
3082
3083         if (IS_ERR(inode)) {
3084                 BUG_ON(retries);
3085                 retries++;
3086
3087                 if (block_group->ro)
3088                         goto out_free;
3089
3090                 ret = create_free_space_inode(root, trans, block_group, path);
3091                 if (ret)
3092                         goto out_free;
3093                 goto again;
3094         }
3095
3096         /* We've already setup this transaction, go ahead and exit */
3097         if (block_group->cache_generation == trans->transid &&
3098             i_size_read(inode)) {
3099                 dcs = BTRFS_DC_SETUP;
3100                 goto out_put;
3101         }
3102
3103         /*
3104          * We want to set the generation to 0, that way if anything goes wrong
3105          * from here on out we know not to trust this cache when we load up next
3106          * time.
3107          */
3108         BTRFS_I(inode)->generation = 0;
3109         ret = btrfs_update_inode(trans, root, inode);
3110         WARN_ON(ret);
3111
3112         if (i_size_read(inode) > 0) {
3113                 ret = btrfs_check_trunc_cache_free_space(root,
3114                                         &root->fs_info->global_block_rsv);
3115                 if (ret)
3116                         goto out_put;
3117
3118                 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3119                 if (ret)
3120                         goto out_put;
3121         }
3122
3123         spin_lock(&block_group->lock);
3124         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3125             !btrfs_test_opt(root, SPACE_CACHE)) {
3126                 /*
3127                  * don't bother trying to write stuff out _if_
3128                  * a) we're not cached,
3129                  * b) we're with nospace_cache mount option.
3130                  */
3131                 dcs = BTRFS_DC_WRITTEN;
3132                 spin_unlock(&block_group->lock);
3133                 goto out_put;
3134         }
3135         spin_unlock(&block_group->lock);
3136
3137         /*
3138          * Try to preallocate enough space based on how big the block group is.
3139          * Keep in mind this has to include any pinned space which could end up
3140          * taking up quite a bit since it's not folded into the other space
3141          * cache.
3142          */
3143         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3144         if (!num_pages)
3145                 num_pages = 1;
3146
3147         num_pages *= 16;
3148         num_pages *= PAGE_CACHE_SIZE;
3149
3150         ret = btrfs_check_data_free_space(inode, num_pages);
3151         if (ret)
3152                 goto out_put;
3153
3154         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3155                                               num_pages, num_pages,
3156                                               &alloc_hint);
3157         if (!ret)
3158                 dcs = BTRFS_DC_SETUP;
3159         btrfs_free_reserved_data_space(inode, num_pages);
3160
3161 out_put:
3162         iput(inode);
3163 out_free:
3164         btrfs_release_path(path);
3165 out:
3166         spin_lock(&block_group->lock);
3167         if (!ret && dcs == BTRFS_DC_SETUP)
3168                 block_group->cache_generation = trans->transid;
3169         block_group->disk_cache_state = dcs;
3170         spin_unlock(&block_group->lock);
3171
3172         return ret;
3173 }
3174
3175 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3176                                    struct btrfs_root *root)
3177 {
3178         struct btrfs_block_group_cache *cache;
3179         int err = 0;
3180         struct btrfs_path *path;
3181         u64 last = 0;
3182
3183         path = btrfs_alloc_path();
3184         if (!path)
3185                 return -ENOMEM;
3186
3187 again:
3188         while (1) {
3189                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3190                 while (cache) {
3191                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3192                                 break;
3193                         cache = next_block_group(root, cache);
3194                 }
3195                 if (!cache) {
3196                         if (last == 0)
3197                                 break;
3198                         last = 0;
3199                         continue;
3200                 }
3201                 err = cache_save_setup(cache, trans, path);
3202                 last = cache->key.objectid + cache->key.offset;
3203                 btrfs_put_block_group(cache);
3204         }
3205
3206         while (1) {
3207                 if (last == 0) {
3208                         err = btrfs_run_delayed_refs(trans, root,
3209                                                      (unsigned long)-1);
3210                         if (err) /* File system offline */
3211                                 goto out;
3212                 }
3213
3214                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3215                 while (cache) {
3216                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3217                                 btrfs_put_block_group(cache);
3218                                 goto again;
3219                         }
3220
3221                         if (cache->dirty)
3222                                 break;
3223                         cache = next_block_group(root, cache);
3224                 }
3225                 if (!cache) {
3226                         if (last == 0)
3227                                 break;
3228                         last = 0;
3229                         continue;
3230                 }
3231
3232                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3233                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3234                 cache->dirty = 0;
3235                 last = cache->key.objectid + cache->key.offset;
3236
3237                 err = write_one_cache_group(trans, root, path, cache);
3238                 btrfs_put_block_group(cache);
3239                 if (err) /* File system offline */
3240                         goto out;
3241         }
3242
3243         while (1) {
3244                 /*
3245                  * I don't think this is needed since we're just marking our
3246                  * preallocated extent as written, but just in case it can't
3247                  * hurt.
3248                  */
3249                 if (last == 0) {
3250                         err = btrfs_run_delayed_refs(trans, root,
3251                                                      (unsigned long)-1);
3252                         if (err) /* File system offline */
3253                                 goto out;
3254                 }
3255
3256                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3257                 while (cache) {
3258                         /*
3259                          * Really this shouldn't happen, but it could if we
3260                          * couldn't write the entire preallocated extent and
3261                          * splitting the extent resulted in a new block.
3262                          */
3263                         if (cache->dirty) {
3264                                 btrfs_put_block_group(cache);
3265                                 goto again;
3266                         }
3267                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3268                                 break;
3269                         cache = next_block_group(root, cache);
3270                 }
3271                 if (!cache) {
3272                         if (last == 0)
3273                                 break;
3274                         last = 0;
3275                         continue;
3276                 }
3277
3278                 err = btrfs_write_out_cache(root, trans, cache, path);
3279
3280                 /*
3281                  * If we didn't have an error then the cache state is still
3282                  * NEED_WRITE, so we can set it to WRITTEN.
3283                  */
3284                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3285                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3286                 last = cache->key.objectid + cache->key.offset;
3287                 btrfs_put_block_group(cache);
3288         }
3289 out:
3290
3291         btrfs_free_path(path);
3292         return err;
3293 }
3294
3295 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3296 {
3297         struct btrfs_block_group_cache *block_group;
3298         int readonly = 0;
3299
3300         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3301         if (!block_group || block_group->ro)
3302                 readonly = 1;
3303         if (block_group)
3304                 btrfs_put_block_group(block_group);
3305         return readonly;
3306 }
3307
3308 static const char *alloc_name(u64 flags)
3309 {
3310         switch (flags) {
3311         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3312                 return "mixed";
3313         case BTRFS_BLOCK_GROUP_METADATA:
3314                 return "metadata";
3315         case BTRFS_BLOCK_GROUP_DATA:
3316                 return "data";
3317         case BTRFS_BLOCK_GROUP_SYSTEM:
3318                 return "system";
3319         default:
3320                 WARN_ON(1);
3321                 return "invalid-combination";
3322         };
3323 }
3324
3325 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3326                              u64 total_bytes, u64 bytes_used,
3327                              struct btrfs_space_info **space_info)
3328 {
3329         struct btrfs_space_info *found;
3330         int i;
3331         int factor;
3332         int ret;
3333
3334         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3335                      BTRFS_BLOCK_GROUP_RAID10))
3336                 factor = 2;
3337         else
3338                 factor = 1;
3339
3340         found = __find_space_info(info, flags);
3341         if (found) {
3342                 spin_lock(&found->lock);
3343                 found->total_bytes += total_bytes;
3344                 found->disk_total += total_bytes * factor;
3345                 found->bytes_used += bytes_used;
3346                 found->disk_used += bytes_used * factor;
3347                 found->full = 0;
3348                 spin_unlock(&found->lock);
3349                 *space_info = found;
3350                 return 0;
3351         }
3352         found = kzalloc(sizeof(*found), GFP_NOFS);
3353         if (!found)
3354                 return -ENOMEM;
3355
3356         ret = percpu_counter_init(&found->total_bytes_pinned, 0);
3357         if (ret) {
3358                 kfree(found);
3359                 return ret;
3360         }
3361
3362         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
3363                 INIT_LIST_HEAD(&found->block_groups[i]);
3364                 kobject_init(&found->block_group_kobjs[i], &btrfs_raid_ktype);
3365         }
3366         init_rwsem(&found->groups_sem);
3367         spin_lock_init(&found->lock);
3368         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3369         found->total_bytes = total_bytes;
3370         found->disk_total = total_bytes * factor;
3371         found->bytes_used = bytes_used;
3372         found->disk_used = bytes_used * factor;
3373         found->bytes_pinned = 0;
3374         found->bytes_reserved = 0;
3375         found->bytes_readonly = 0;
3376         found->bytes_may_use = 0;
3377         found->full = 0;
3378         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3379         found->chunk_alloc = 0;
3380         found->flush = 0;
3381         init_waitqueue_head(&found->wait);
3382
3383         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3384                                     info->space_info_kobj, "%s",
3385                                     alloc_name(found->flags));
3386         if (ret) {
3387                 kfree(found);
3388                 return ret;
3389         }
3390
3391         *space_info = found;
3392         list_add_rcu(&found->list, &info->space_info);
3393         if (flags & BTRFS_BLOCK_GROUP_DATA)
3394                 info->data_sinfo = found;
3395
3396         return ret;
3397 }
3398
3399 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3400 {
3401         u64 extra_flags = chunk_to_extended(flags) &
3402                                 BTRFS_EXTENDED_PROFILE_MASK;
3403
3404         write_seqlock(&fs_info->profiles_lock);
3405         if (flags & BTRFS_BLOCK_GROUP_DATA)
3406                 fs_info->avail_data_alloc_bits |= extra_flags;
3407         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3408                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3409         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3410                 fs_info->avail_system_alloc_bits |= extra_flags;
3411         write_sequnlock(&fs_info->profiles_lock);
3412 }
3413
3414 /*
3415  * returns target flags in extended format or 0 if restripe for this
3416  * chunk_type is not in progress
3417  *
3418  * should be called with either volume_mutex or balance_lock held
3419  */
3420 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3421 {
3422         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3423         u64 target = 0;
3424
3425         if (!bctl)
3426                 return 0;
3427
3428         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3429             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3430                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3431         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3432                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3433                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3434         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3435                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3436                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3437         }
3438
3439         return target;
3440 }
3441
3442 /*
3443  * @flags: available profiles in extended format (see ctree.h)
3444  *
3445  * Returns reduced profile in chunk format.  If profile changing is in
3446  * progress (either running or paused) picks the target profile (if it's
3447  * already available), otherwise falls back to plain reducing.
3448  */
3449 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3450 {
3451         /*
3452          * we add in the count of missing devices because we want
3453          * to make sure that any RAID levels on a degraded FS
3454          * continue to be honored.
3455          */
3456         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3457                 root->fs_info->fs_devices->missing_devices;
3458         u64 target;
3459         u64 tmp;
3460
3461         /*
3462          * see if restripe for this chunk_type is in progress, if so
3463          * try to reduce to the target profile
3464          */
3465         spin_lock(&root->fs_info->balance_lock);
3466         target = get_restripe_target(root->fs_info, flags);
3467         if (target) {
3468                 /* pick target profile only if it's already available */
3469                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3470                         spin_unlock(&root->fs_info->balance_lock);
3471                         return extended_to_chunk(target);
3472                 }
3473         }
3474         spin_unlock(&root->fs_info->balance_lock);
3475
3476         /* First, mask out the RAID levels which aren't possible */
3477         if (num_devices == 1)
3478                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3479                            BTRFS_BLOCK_GROUP_RAID5);
3480         if (num_devices < 3)
3481                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3482         if (num_devices < 4)
3483                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3484
3485         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3486                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3487                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3488         flags &= ~tmp;
3489
3490         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3491                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3492         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3493                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3494         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3495                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3496         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3497                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3498         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3499                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3500
3501         return extended_to_chunk(flags | tmp);
3502 }
3503
3504 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3505 {
3506         unsigned seq;
3507
3508         do {
3509                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3510
3511                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3512                         flags |= root->fs_info->avail_data_alloc_bits;
3513                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3514                         flags |= root->fs_info->avail_system_alloc_bits;
3515                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3516                         flags |= root->fs_info->avail_metadata_alloc_bits;
3517         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3518
3519         return btrfs_reduce_alloc_profile(root, flags);
3520 }
3521
3522 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3523 {
3524         u64 flags;
3525         u64 ret;
3526
3527         if (data)
3528                 flags = BTRFS_BLOCK_GROUP_DATA;
3529         else if (root == root->fs_info->chunk_root)
3530                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3531         else
3532                 flags = BTRFS_BLOCK_GROUP_METADATA;
3533
3534         ret = get_alloc_profile(root, flags);
3535         return ret;
3536 }
3537
3538 /*
3539  * This will check the space that the inode allocates from to make sure we have
3540  * enough space for bytes.
3541  */
3542 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3543 {
3544         struct btrfs_space_info *data_sinfo;
3545         struct btrfs_root *root = BTRFS_I(inode)->root;
3546         struct btrfs_fs_info *fs_info = root->fs_info;
3547         u64 used;
3548         int ret = 0, committed = 0, alloc_chunk = 1;
3549
3550         /* make sure bytes are sectorsize aligned */
3551         bytes = ALIGN(bytes, root->sectorsize);
3552
3553         if (btrfs_is_free_space_inode(inode)) {
3554                 committed = 1;
3555                 ASSERT(current->journal_info);
3556         }
3557
3558         data_sinfo = fs_info->data_sinfo;
3559         if (!data_sinfo)
3560                 goto alloc;
3561
3562 again:
3563         /* make sure we have enough space to handle the data first */
3564         spin_lock(&data_sinfo->lock);
3565         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3566                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3567                 data_sinfo->bytes_may_use;
3568
3569         if (used + bytes > data_sinfo->total_bytes) {
3570                 struct btrfs_trans_handle *trans;
3571
3572                 /*
3573                  * if we don't have enough free bytes in this space then we need
3574                  * to alloc a new chunk.
3575                  */
3576                 if (!data_sinfo->full && alloc_chunk) {
3577                         u64 alloc_target;
3578
3579                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3580                         spin_unlock(&data_sinfo->lock);
3581 alloc:
3582                         alloc_target = btrfs_get_alloc_profile(root, 1);
3583                         /*
3584                          * It is ugly that we don't call nolock join
3585                          * transaction for the free space inode case here.
3586                          * But it is safe because we only do the data space
3587                          * reservation for the free space cache in the
3588                          * transaction context, the common join transaction
3589                          * just increase the counter of the current transaction
3590                          * handler, doesn't try to acquire the trans_lock of
3591                          * the fs.
3592                          */
3593                         trans = btrfs_join_transaction(root);
3594                         if (IS_ERR(trans))
3595                                 return PTR_ERR(trans);
3596
3597                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3598                                              alloc_target,
3599                                              CHUNK_ALLOC_NO_FORCE);
3600                         btrfs_end_transaction(trans, root);
3601                         if (ret < 0) {
3602                                 if (ret != -ENOSPC)
3603                                         return ret;
3604                                 else
3605                                         goto commit_trans;
3606                         }
3607
3608                         if (!data_sinfo)
3609                                 data_sinfo = fs_info->data_sinfo;
3610
3611                         goto again;
3612                 }
3613
3614                 /*
3615                  * If we don't have enough pinned space to deal with this
3616                  * allocation don't bother committing the transaction.
3617                  */
3618                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
3619                                            bytes) < 0)
3620                         committed = 1;
3621                 spin_unlock(&data_sinfo->lock);
3622
3623                 /* commit the current transaction and try again */
3624 commit_trans:
3625                 if (!committed &&
3626                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3627                         committed = 1;
3628
3629                         trans = btrfs_join_transaction(root);
3630                         if (IS_ERR(trans))
3631                                 return PTR_ERR(trans);
3632                         ret = btrfs_commit_transaction(trans, root);
3633                         if (ret)
3634                                 return ret;
3635                         goto again;
3636                 }
3637
3638                 trace_btrfs_space_reservation(root->fs_info,
3639                                               "space_info:enospc",
3640                                               data_sinfo->flags, bytes, 1);
3641                 return -ENOSPC;
3642         }
3643         data_sinfo->bytes_may_use += bytes;
3644         trace_btrfs_space_reservation(root->fs_info, "space_info",
3645                                       data_sinfo->flags, bytes, 1);
3646         spin_unlock(&data_sinfo->lock);
3647
3648         return 0;
3649 }
3650
3651 /*
3652  * Called if we need to clear a data reservation for this inode.
3653  */
3654 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3655 {
3656         struct btrfs_root *root = BTRFS_I(inode)->root;
3657         struct btrfs_space_info *data_sinfo;
3658
3659         /* make sure bytes are sectorsize aligned */
3660         bytes = ALIGN(bytes, root->sectorsize);
3661
3662         data_sinfo = root->fs_info->data_sinfo;
3663         spin_lock(&data_sinfo->lock);
3664         WARN_ON(data_sinfo->bytes_may_use < bytes);
3665         data_sinfo->bytes_may_use -= bytes;
3666         trace_btrfs_space_reservation(root->fs_info, "space_info",
3667                                       data_sinfo->flags, bytes, 0);
3668         spin_unlock(&data_sinfo->lock);
3669 }
3670
3671 static void force_metadata_allocation(struct btrfs_fs_info *info)
3672 {
3673         struct list_head *head = &info->space_info;
3674         struct btrfs_space_info *found;
3675
3676         rcu_read_lock();
3677         list_for_each_entry_rcu(found, head, list) {
3678                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3679                         found->force_alloc = CHUNK_ALLOC_FORCE;
3680         }
3681         rcu_read_unlock();
3682 }
3683
3684 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3685 {
3686         return (global->size << 1);
3687 }
3688
3689 static int should_alloc_chunk(struct btrfs_root *root,
3690                               struct btrfs_space_info *sinfo, int force)
3691 {
3692         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3693         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3694         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3695         u64 thresh;
3696
3697         if (force == CHUNK_ALLOC_FORCE)
3698                 return 1;
3699
3700         /*
3701          * We need to take into account the global rsv because for all intents
3702          * and purposes it's used space.  Don't worry about locking the
3703          * global_rsv, it doesn't change except when the transaction commits.
3704          */
3705         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3706                 num_allocated += calc_global_rsv_need_space(global_rsv);
3707
3708         /*
3709          * in limited mode, we want to have some free space up to
3710          * about 1% of the FS size.
3711          */
3712         if (force == CHUNK_ALLOC_LIMITED) {
3713                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3714                 thresh = max_t(u64, 64 * 1024 * 1024,
3715                                div_factor_fine(thresh, 1));
3716
3717                 if (num_bytes - num_allocated < thresh)
3718                         return 1;
3719         }
3720
3721         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3722                 return 0;
3723         return 1;
3724 }
3725
3726 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3727 {
3728         u64 num_dev;
3729
3730         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3731                     BTRFS_BLOCK_GROUP_RAID0 |
3732                     BTRFS_BLOCK_GROUP_RAID5 |
3733                     BTRFS_BLOCK_GROUP_RAID6))
3734                 num_dev = root->fs_info->fs_devices->rw_devices;
3735         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3736                 num_dev = 2;
3737         else
3738                 num_dev = 1;    /* DUP or single */
3739
3740         /* metadata for updaing devices and chunk tree */
3741         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3742 }
3743
3744 static void check_system_chunk(struct btrfs_trans_handle *trans,
3745                                struct btrfs_root *root, u64 type)
3746 {
3747         struct btrfs_space_info *info;
3748         u64 left;
3749         u64 thresh;
3750
3751         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3752         spin_lock(&info->lock);
3753         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3754                 info->bytes_reserved - info->bytes_readonly;
3755         spin_unlock(&info->lock);
3756
3757         thresh = get_system_chunk_thresh(root, type);
3758         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3759                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3760                         left, thresh, type);
3761                 dump_space_info(info, 0, 0);
3762         }
3763
3764         if (left < thresh) {
3765                 u64 flags;
3766
3767                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3768                 btrfs_alloc_chunk(trans, root, flags);
3769         }
3770 }
3771
3772 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3773                           struct btrfs_root *extent_root, u64 flags, int force)
3774 {
3775         struct btrfs_space_info *space_info;
3776         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3777         int wait_for_alloc = 0;
3778         int ret = 0;
3779
3780         /* Don't re-enter if we're already allocating a chunk */
3781         if (trans->allocating_chunk)
3782                 return -ENOSPC;
3783
3784         space_info = __find_space_info(extent_root->fs_info, flags);
3785         if (!space_info) {
3786                 ret = update_space_info(extent_root->fs_info, flags,
3787                                         0, 0, &space_info);
3788                 BUG_ON(ret); /* -ENOMEM */
3789         }
3790         BUG_ON(!space_info); /* Logic error */
3791
3792 again:
3793         spin_lock(&space_info->lock);
3794         if (force < space_info->force_alloc)
3795                 force = space_info->force_alloc;
3796         if (space_info->full) {
3797                 if (should_alloc_chunk(extent_root, space_info, force))
3798                         ret = -ENOSPC;
3799                 else
3800                         ret = 0;
3801                 spin_unlock(&space_info->lock);
3802                 return ret;
3803         }
3804
3805         if (!should_alloc_chunk(extent_root, space_info, force)) {
3806                 spin_unlock(&space_info->lock);
3807                 return 0;
3808         } else if (space_info->chunk_alloc) {
3809                 wait_for_alloc = 1;
3810         } else {
3811                 space_info->chunk_alloc = 1;
3812         }
3813
3814         spin_unlock(&space_info->lock);
3815
3816         mutex_lock(&fs_info->chunk_mutex);
3817
3818         /*
3819          * The chunk_mutex is held throughout the entirety of a chunk
3820          * allocation, so once we've acquired the chunk_mutex we know that the
3821          * other guy is done and we need to recheck and see if we should
3822          * allocate.
3823          */
3824         if (wait_for_alloc) {
3825                 mutex_unlock(&fs_info->chunk_mutex);
3826                 wait_for_alloc = 0;
3827                 goto again;
3828         }
3829
3830         trans->allocating_chunk = true;
3831
3832         /*
3833          * If we have mixed data/metadata chunks we want to make sure we keep
3834          * allocating mixed chunks instead of individual chunks.
3835          */
3836         if (btrfs_mixed_space_info(space_info))
3837                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3838
3839         /*
3840          * if we're doing a data chunk, go ahead and make sure that
3841          * we keep a reasonable number of metadata chunks allocated in the
3842          * FS as well.
3843          */
3844         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3845                 fs_info->data_chunk_allocations++;
3846                 if (!(fs_info->data_chunk_allocations %
3847                       fs_info->metadata_ratio))
3848                         force_metadata_allocation(fs_info);
3849         }
3850
3851         /*
3852          * Check if we have enough space in SYSTEM chunk because we may need
3853          * to update devices.
3854          */
3855         check_system_chunk(trans, extent_root, flags);
3856
3857         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3858         trans->allocating_chunk = false;
3859
3860         spin_lock(&space_info->lock);
3861         if (ret < 0 && ret != -ENOSPC)
3862                 goto out;
3863         if (ret)
3864                 space_info->full = 1;
3865         else
3866                 ret = 1;
3867
3868         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3869 out:
3870         space_info->chunk_alloc = 0;
3871         spin_unlock(&space_info->lock);
3872         mutex_unlock(&fs_info->chunk_mutex);
3873         return ret;
3874 }
3875
3876 static int can_overcommit(struct btrfs_root *root,
3877                           struct btrfs_space_info *space_info, u64 bytes,
3878                           enum btrfs_reserve_flush_enum flush)
3879 {
3880         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3881         u64 profile = btrfs_get_alloc_profile(root, 0);
3882         u64 space_size;
3883         u64 avail;
3884         u64 used;
3885
3886         used = space_info->bytes_used + space_info->bytes_reserved +
3887                 space_info->bytes_pinned + space_info->bytes_readonly;
3888
3889         /*
3890          * We only want to allow over committing if we have lots of actual space
3891          * free, but if we don't have enough space to handle the global reserve
3892          * space then we could end up having a real enospc problem when trying
3893          * to allocate a chunk or some other such important allocation.
3894          */
3895         spin_lock(&global_rsv->lock);
3896         space_size = calc_global_rsv_need_space(global_rsv);
3897         spin_unlock(&global_rsv->lock);
3898         if (used + space_size >= space_info->total_bytes)
3899                 return 0;
3900
3901         used += space_info->bytes_may_use;
3902
3903         spin_lock(&root->fs_info->free_chunk_lock);
3904         avail = root->fs_info->free_chunk_space;
3905         spin_unlock(&root->fs_info->free_chunk_lock);
3906
3907         /*
3908          * If we have dup, raid1 or raid10 then only half of the free
3909          * space is actually useable.  For raid56, the space info used
3910          * doesn't include the parity drive, so we don't have to
3911          * change the math
3912          */
3913         if (profile & (BTRFS_BLOCK_GROUP_DUP |
3914                        BTRFS_BLOCK_GROUP_RAID1 |
3915                        BTRFS_BLOCK_GROUP_RAID10))
3916                 avail >>= 1;
3917
3918         /*
3919          * If we aren't flushing all things, let us overcommit up to
3920          * 1/2th of the space. If we can flush, don't let us overcommit
3921          * too much, let it overcommit up to 1/8 of the space.
3922          */
3923         if (flush == BTRFS_RESERVE_FLUSH_ALL)
3924                 avail >>= 3;
3925         else
3926                 avail >>= 1;
3927
3928         if (used + bytes < space_info->total_bytes + avail)
3929                 return 1;
3930         return 0;
3931 }
3932
3933 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
3934                                          unsigned long nr_pages)
3935 {
3936         struct super_block *sb = root->fs_info->sb;
3937
3938         if (down_read_trylock(&sb->s_umount)) {
3939                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
3940                 up_read(&sb->s_umount);
3941         } else {
3942                 /*
3943                  * We needn't worry the filesystem going from r/w to r/o though
3944                  * we don't acquire ->s_umount mutex, because the filesystem
3945                  * should guarantee the delalloc inodes list be empty after
3946                  * the filesystem is readonly(all dirty pages are written to
3947                  * the disk).
3948                  */
3949                 btrfs_start_delalloc_roots(root->fs_info, 0);
3950                 if (!current->journal_info)
3951                         btrfs_wait_ordered_roots(root->fs_info, -1);
3952         }
3953 }
3954
3955 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
3956 {
3957         u64 bytes;
3958         int nr;
3959
3960         bytes = btrfs_calc_trans_metadata_size(root, 1);
3961         nr = (int)div64_u64(to_reclaim, bytes);
3962         if (!nr)
3963                 nr = 1;
3964         return nr;
3965 }
3966
3967 #define EXTENT_SIZE_PER_ITEM    (256 * 1024)
3968
3969 /*
3970  * shrink metadata reservation for delalloc
3971  */
3972 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
3973                             bool wait_ordered)
3974 {
3975         struct btrfs_block_rsv *block_rsv;
3976         struct btrfs_space_info *space_info;
3977         struct btrfs_trans_handle *trans;
3978         u64 delalloc_bytes;
3979         u64 max_reclaim;
3980         long time_left;
3981         unsigned long nr_pages;
3982         int loops;
3983         int items;
3984         enum btrfs_reserve_flush_enum flush;
3985
3986         /* Calc the number of the pages we need flush for space reservation */
3987         items = calc_reclaim_items_nr(root, to_reclaim);
3988         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
3989
3990         trans = (struct btrfs_trans_handle *)current->journal_info;
3991         block_rsv = &root->fs_info->delalloc_block_rsv;
3992         space_info = block_rsv->space_info;
3993
3994         delalloc_bytes = percpu_counter_sum_positive(
3995                                                 &root->fs_info->delalloc_bytes);
3996         if (delalloc_bytes == 0) {
3997                 if (trans)
3998                         return;
3999                 if (wait_ordered)
4000                         btrfs_wait_ordered_roots(root->fs_info, items);
4001                 return;
4002         }
4003
4004         loops = 0;
4005         while (delalloc_bytes && loops < 3) {
4006                 max_reclaim = min(delalloc_bytes, to_reclaim);
4007                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4008                 btrfs_writeback_inodes_sb_nr(root, nr_pages);
4009                 /*
4010                  * We need to wait for the async pages to actually start before
4011                  * we do anything.
4012                  */
4013                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4014                 if (!max_reclaim)
4015                         goto skip_async;
4016
4017                 if (max_reclaim <= nr_pages)
4018                         max_reclaim = 0;
4019                 else
4020                         max_reclaim -= nr_pages;
4021
4022                 wait_event(root->fs_info->async_submit_wait,
4023                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4024                            (int)max_reclaim);
4025 skip_async:
4026                 if (!trans)
4027                         flush = BTRFS_RESERVE_FLUSH_ALL;
4028                 else
4029                         flush = BTRFS_RESERVE_NO_FLUSH;
4030                 spin_lock(&space_info->lock);
4031                 if (can_overcommit(root, space_info, orig, flush)) {
4032                         spin_unlock(&space_info->lock);
4033                         break;
4034                 }
4035                 spin_unlock(&space_info->lock);
4036
4037                 loops++;
4038                 if (wait_ordered && !trans) {
4039                         btrfs_wait_ordered_roots(root->fs_info, items);
4040                 } else {
4041                         time_left = schedule_timeout_killable(1);
4042                         if (time_left)
4043                                 break;
4044                 }
4045                 delalloc_bytes = percpu_counter_sum_positive(
4046                                                 &root->fs_info->delalloc_bytes);
4047         }
4048 }
4049
4050 /**
4051  * maybe_commit_transaction - possibly commit the transaction if its ok to
4052  * @root - the root we're allocating for
4053  * @bytes - the number of bytes we want to reserve
4054  * @force - force the commit
4055  *
4056  * This will check to make sure that committing the transaction will actually
4057  * get us somewhere and then commit the transaction if it does.  Otherwise it
4058  * will return -ENOSPC.
4059  */
4060 static int may_commit_transaction(struct btrfs_root *root,
4061                                   struct btrfs_space_info *space_info,
4062                                   u64 bytes, int force)
4063 {
4064         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4065         struct btrfs_trans_handle *trans;
4066
4067         trans = (struct btrfs_trans_handle *)current->journal_info;
4068         if (trans)
4069                 return -EAGAIN;
4070
4071         if (force)
4072                 goto commit;
4073
4074         /* See if there is enough pinned space to make this reservation */
4075         spin_lock(&space_info->lock);
4076         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4077                                    bytes) >= 0) {
4078                 spin_unlock(&space_info->lock);
4079                 goto commit;
4080         }
4081         spin_unlock(&space_info->lock);
4082
4083         /*
4084          * See if there is some space in the delayed insertion reservation for
4085          * this reservation.
4086          */
4087         if (space_info != delayed_rsv->space_info)
4088                 return -ENOSPC;
4089
4090         spin_lock(&space_info->lock);
4091         spin_lock(&delayed_rsv->lock);
4092         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4093                                    bytes - delayed_rsv->size) >= 0) {
4094                 spin_unlock(&delayed_rsv->lock);
4095                 spin_unlock(&space_info->lock);
4096                 return -ENOSPC;
4097         }
4098         spin_unlock(&delayed_rsv->lock);
4099         spin_unlock(&space_info->lock);
4100
4101 commit:
4102         trans = btrfs_join_transaction(root);
4103         if (IS_ERR(trans))
4104                 return -ENOSPC;
4105
4106         return btrfs_commit_transaction(trans, root);
4107 }
4108
4109 enum flush_state {
4110         FLUSH_DELAYED_ITEMS_NR  =       1,
4111         FLUSH_DELAYED_ITEMS     =       2,
4112         FLUSH_DELALLOC          =       3,
4113         FLUSH_DELALLOC_WAIT     =       4,
4114         ALLOC_CHUNK             =       5,
4115         COMMIT_TRANS            =       6,
4116 };
4117
4118 static int flush_space(struct btrfs_root *root,
4119                        struct btrfs_space_info *space_info, u64 num_bytes,
4120                        u64 orig_bytes, int state)
4121 {
4122         struct btrfs_trans_handle *trans;
4123         int nr;
4124         int ret = 0;
4125
4126         switch (state) {
4127         case FLUSH_DELAYED_ITEMS_NR:
4128         case FLUSH_DELAYED_ITEMS:
4129                 if (state == FLUSH_DELAYED_ITEMS_NR)
4130                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4131                 else
4132                         nr = -1;
4133
4134                 trans = btrfs_join_transaction(root);
4135                 if (IS_ERR(trans)) {
4136                         ret = PTR_ERR(trans);
4137                         break;
4138                 }
4139                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4140                 btrfs_end_transaction(trans, root);
4141                 break;
4142         case FLUSH_DELALLOC:
4143         case FLUSH_DELALLOC_WAIT:
4144                 shrink_delalloc(root, num_bytes, orig_bytes,
4145                                 state == FLUSH_DELALLOC_WAIT);
4146                 break;
4147         case ALLOC_CHUNK:
4148                 trans = btrfs_join_transaction(root);
4149                 if (IS_ERR(trans)) {
4150                         ret = PTR_ERR(trans);
4151                         break;
4152                 }
4153                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4154                                      btrfs_get_alloc_profile(root, 0),
4155                                      CHUNK_ALLOC_NO_FORCE);
4156                 btrfs_end_transaction(trans, root);
4157                 if (ret == -ENOSPC)
4158                         ret = 0;
4159                 break;
4160         case COMMIT_TRANS:
4161                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4162                 break;
4163         default:
4164                 ret = -ENOSPC;
4165                 break;
4166         }
4167
4168         return ret;
4169 }
4170 /**
4171  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4172  * @root - the root we're allocating for
4173  * @block_rsv - the block_rsv we're allocating for
4174  * @orig_bytes - the number of bytes we want
4175  * @flush - whether or not we can flush to make our reservation
4176  *
4177  * This will reserve orgi_bytes number of bytes from the space info associated
4178  * with the block_rsv.  If there is not enough space it will make an attempt to
4179  * flush out space to make room.  It will do this by flushing delalloc if
4180  * possible or committing the transaction.  If flush is 0 then no attempts to
4181  * regain reservations will be made and this will fail if there is not enough
4182  * space already.
4183  */
4184 static int reserve_metadata_bytes(struct btrfs_root *root,
4185                                   struct btrfs_block_rsv *block_rsv,
4186                                   u64 orig_bytes,
4187                                   enum btrfs_reserve_flush_enum flush)
4188 {
4189         struct btrfs_space_info *space_info = block_rsv->space_info;
4190         u64 used;
4191         u64 num_bytes = orig_bytes;
4192         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4193         int ret = 0;
4194         bool flushing = false;
4195
4196 again:
4197         ret = 0;
4198         spin_lock(&space_info->lock);
4199         /*
4200          * We only want to wait if somebody other than us is flushing and we
4201          * are actually allowed to flush all things.
4202          */
4203         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4204                space_info->flush) {
4205                 spin_unlock(&space_info->lock);
4206                 /*
4207                  * If we have a trans handle we can't wait because the flusher
4208                  * may have to commit the transaction, which would mean we would
4209                  * deadlock since we are waiting for the flusher to finish, but
4210                  * hold the current transaction open.
4211                  */
4212                 if (current->journal_info)
4213                         return -EAGAIN;
4214                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4215                 /* Must have been killed, return */
4216                 if (ret)
4217                         return -EINTR;
4218
4219                 spin_lock(&space_info->lock);
4220         }
4221
4222         ret = -ENOSPC;
4223         used = space_info->bytes_used + space_info->bytes_reserved +
4224                 space_info->bytes_pinned + space_info->bytes_readonly +
4225                 space_info->bytes_may_use;
4226
4227         /*
4228          * The idea here is that we've not already over-reserved the block group
4229          * then we can go ahead and save our reservation first and then start
4230          * flushing if we need to.  Otherwise if we've already overcommitted
4231          * lets start flushing stuff first and then come back and try to make
4232          * our reservation.
4233          */
4234         if (used <= space_info->total_bytes) {
4235                 if (used + orig_bytes <= space_info->total_bytes) {
4236                         space_info->bytes_may_use += orig_bytes;
4237                         trace_btrfs_space_reservation(root->fs_info,
4238                                 "space_info", space_info->flags, orig_bytes, 1);
4239                         ret = 0;
4240                 } else {
4241                         /*
4242                          * Ok set num_bytes to orig_bytes since we aren't
4243                          * overocmmitted, this way we only try and reclaim what
4244                          * we need.
4245                          */
4246                         num_bytes = orig_bytes;
4247                 }
4248         } else {
4249                 /*
4250                  * Ok we're over committed, set num_bytes to the overcommitted
4251                  * amount plus the amount of bytes that we need for this
4252                  * reservation.
4253                  */
4254                 num_bytes = used - space_info->total_bytes +
4255                         (orig_bytes * 2);
4256         }
4257
4258         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4259                 space_info->bytes_may_use += orig_bytes;
4260                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4261                                               space_info->flags, orig_bytes,
4262                                               1);
4263                 ret = 0;
4264         }
4265
4266         /*
4267          * Couldn't make our reservation, save our place so while we're trying
4268          * to reclaim space we can actually use it instead of somebody else
4269          * stealing it from us.
4270          *
4271          * We make the other tasks wait for the flush only when we can flush
4272          * all things.
4273          */
4274         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4275                 flushing = true;
4276                 space_info->flush = 1;
4277         }
4278
4279         spin_unlock(&space_info->lock);
4280
4281         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4282                 goto out;
4283
4284         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4285                           flush_state);
4286         flush_state++;
4287
4288         /*
4289          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4290          * would happen. So skip delalloc flush.
4291          */
4292         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4293             (flush_state == FLUSH_DELALLOC ||
4294              flush_state == FLUSH_DELALLOC_WAIT))
4295                 flush_state = ALLOC_CHUNK;
4296
4297         if (!ret)
4298                 goto again;
4299         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4300                  flush_state < COMMIT_TRANS)
4301                 goto again;
4302         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4303                  flush_state <= COMMIT_TRANS)
4304                 goto again;
4305
4306 out:
4307         if (ret == -ENOSPC &&
4308             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4309                 struct btrfs_block_rsv *global_rsv =
4310                         &root->fs_info->global_block_rsv;
4311
4312                 if (block_rsv != global_rsv &&
4313                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4314                         ret = 0;
4315         }
4316         if (ret == -ENOSPC)
4317                 trace_btrfs_space_reservation(root->fs_info,
4318                                               "space_info:enospc",
4319                                               space_info->flags, orig_bytes, 1);
4320         if (flushing) {
4321                 spin_lock(&space_info->lock);
4322                 space_info->flush = 0;
4323                 wake_up_all(&space_info->wait);
4324                 spin_unlock(&space_info->lock);
4325         }
4326         return ret;
4327 }
4328
4329 static struct btrfs_block_rsv *get_block_rsv(
4330                                         const struct btrfs_trans_handle *trans,
4331                                         const struct btrfs_root *root)
4332 {
4333         struct btrfs_block_rsv *block_rsv = NULL;
4334
4335         if (root->ref_cows)
4336                 block_rsv = trans->block_rsv;
4337
4338         if (root == root->fs_info->csum_root && trans->adding_csums)
4339                 block_rsv = trans->block_rsv;
4340
4341         if (root == root->fs_info->uuid_root)
4342                 block_rsv = trans->block_rsv;
4343
4344         if (!block_rsv)
4345                 block_rsv = root->block_rsv;
4346
4347         if (!block_rsv)
4348                 block_rsv = &root->fs_info->empty_block_rsv;
4349
4350         return block_rsv;
4351 }
4352
4353 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4354                                u64 num_bytes)
4355 {
4356         int ret = -ENOSPC;
4357         spin_lock(&block_rsv->lock);
4358         if (block_rsv->reserved >= num_bytes) {
4359                 block_rsv->reserved -= num_bytes;
4360                 if (block_rsv->reserved < block_rsv->size)
4361                         block_rsv->full = 0;
4362                 ret = 0;
4363         }
4364         spin_unlock(&block_rsv->lock);
4365         return ret;
4366 }
4367
4368 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4369                                 u64 num_bytes, int update_size)
4370 {
4371         spin_lock(&block_rsv->lock);
4372         block_rsv->reserved += num_bytes;
4373         if (update_size)
4374                 block_rsv->size += num_bytes;
4375         else if (block_rsv->reserved >= block_rsv->size)
4376                 block_rsv->full = 1;
4377         spin_unlock(&block_rsv->lock);
4378 }
4379
4380 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4381                              struct btrfs_block_rsv *dest, u64 num_bytes,
4382                              int min_factor)
4383 {
4384         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4385         u64 min_bytes;
4386
4387         if (global_rsv->space_info != dest->space_info)
4388                 return -ENOSPC;
4389
4390         spin_lock(&global_rsv->lock);
4391         min_bytes = div_factor(global_rsv->size, min_factor);
4392         if (global_rsv->reserved < min_bytes + num_bytes) {
4393                 spin_unlock(&global_rsv->lock);
4394                 return -ENOSPC;
4395         }
4396         global_rsv->reserved -= num_bytes;
4397         if (global_rsv->reserved < global_rsv->size)
4398                 global_rsv->full = 0;
4399         spin_unlock(&global_rsv->lock);
4400
4401         block_rsv_add_bytes(dest, num_bytes, 1);
4402         return 0;
4403 }
4404
4405 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4406                                     struct btrfs_block_rsv *block_rsv,
4407                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4408 {
4409         struct btrfs_space_info *space_info = block_rsv->space_info;
4410
4411         spin_lock(&block_rsv->lock);
4412         if (num_bytes == (u64)-1)
4413                 num_bytes = block_rsv->size;
4414         block_rsv->size -= num_bytes;
4415         if (block_rsv->reserved >= block_rsv->size) {
4416                 num_bytes = block_rsv->reserved - block_rsv->size;
4417                 block_rsv->reserved = block_rsv->size;
4418                 block_rsv->full = 1;
4419         } else {
4420                 num_bytes = 0;
4421         }
4422         spin_unlock(&block_rsv->lock);
4423
4424         if (num_bytes > 0) {
4425                 if (dest) {
4426                         spin_lock(&dest->lock);
4427                         if (!dest->full) {
4428                                 u64 bytes_to_add;
4429
4430                                 bytes_to_add = dest->size - dest->reserved;
4431                                 bytes_to_add = min(num_bytes, bytes_to_add);
4432                                 dest->reserved += bytes_to_add;
4433                                 if (dest->reserved >= dest->size)
4434                                         dest->full = 1;
4435                                 num_bytes -= bytes_to_add;
4436                         }
4437                         spin_unlock(&dest->lock);
4438                 }
4439                 if (num_bytes) {
4440                         spin_lock(&space_info->lock);
4441                         space_info->bytes_may_use -= num_bytes;
4442                         trace_btrfs_space_reservation(fs_info, "space_info",
4443                                         space_info->flags, num_bytes, 0);
4444                         spin_unlock(&space_info->lock);
4445                 }
4446         }
4447 }
4448
4449 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4450                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4451 {
4452         int ret;
4453
4454         ret = block_rsv_use_bytes(src, num_bytes);
4455         if (ret)
4456                 return ret;
4457
4458         block_rsv_add_bytes(dst, num_bytes, 1);
4459         return 0;
4460 }
4461
4462 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4463 {
4464         memset(rsv, 0, sizeof(*rsv));
4465         spin_lock_init(&rsv->lock);
4466         rsv->type = type;
4467 }
4468
4469 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4470                                               unsigned short type)
4471 {
4472         struct btrfs_block_rsv *block_rsv;
4473         struct btrfs_fs_info *fs_info = root->fs_info;
4474
4475         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4476         if (!block_rsv)
4477                 return NULL;
4478
4479         btrfs_init_block_rsv(block_rsv, type);
4480         block_rsv->space_info = __find_space_info(fs_info,
4481                                                   BTRFS_BLOCK_GROUP_METADATA);
4482         return block_rsv;
4483 }
4484
4485 void btrfs_free_block_rsv(struct btrfs_root *root,
4486                           struct btrfs_block_rsv *rsv)
4487 {
4488         if (!rsv)
4489                 return;
4490         btrfs_block_rsv_release(root, rsv, (u64)-1);
4491         kfree(rsv);
4492 }
4493
4494 int btrfs_block_rsv_add(struct btrfs_root *root,
4495                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4496                         enum btrfs_reserve_flush_enum flush)
4497 {
4498         int ret;
4499
4500         if (num_bytes == 0)
4501                 return 0;
4502
4503         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4504         if (!ret) {
4505                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4506                 return 0;
4507         }
4508
4509         return ret;
4510 }
4511
4512 int btrfs_block_rsv_check(struct btrfs_root *root,
4513                           struct btrfs_block_rsv *block_rsv, int min_factor)
4514 {
4515         u64 num_bytes = 0;
4516         int ret = -ENOSPC;
4517
4518         if (!block_rsv)
4519                 return 0;
4520
4521         spin_lock(&block_rsv->lock);
4522         num_bytes = div_factor(block_rsv->size, min_factor);
4523         if (block_rsv->reserved >= num_bytes)
4524                 ret = 0;
4525         spin_unlock(&block_rsv->lock);
4526
4527         return ret;
4528 }
4529
4530 int btrfs_block_rsv_refill(struct btrfs_root *root,
4531                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4532                            enum btrfs_reserve_flush_enum flush)
4533 {
4534         u64 num_bytes = 0;
4535         int ret = -ENOSPC;
4536
4537         if (!block_rsv)
4538                 return 0;
4539
4540         spin_lock(&block_rsv->lock);
4541         num_bytes = min_reserved;
4542         if (block_rsv->reserved >= num_bytes)
4543                 ret = 0;
4544         else
4545                 num_bytes -= block_rsv->reserved;
4546         spin_unlock(&block_rsv->lock);
4547
4548         if (!ret)
4549                 return 0;
4550
4551         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4552         if (!ret) {
4553                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4554                 return 0;
4555         }
4556
4557         return ret;
4558 }
4559
4560 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4561                             struct btrfs_block_rsv *dst_rsv,
4562                             u64 num_bytes)
4563 {
4564         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4565 }
4566
4567 void btrfs_block_rsv_release(struct btrfs_root *root,
4568                              struct btrfs_block_rsv *block_rsv,
4569                              u64 num_bytes)
4570 {
4571         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4572         if (global_rsv == block_rsv ||
4573             block_rsv->space_info != global_rsv->space_info)
4574                 global_rsv = NULL;
4575         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4576                                 num_bytes);
4577 }
4578
4579 /*
4580  * helper to calculate size of global block reservation.
4581  * the desired value is sum of space used by extent tree,
4582  * checksum tree and root tree
4583  */
4584 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4585 {
4586         struct btrfs_space_info *sinfo;
4587         u64 num_bytes;
4588         u64 meta_used;
4589         u64 data_used;
4590         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4591
4592         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4593         spin_lock(&sinfo->lock);
4594         data_used = sinfo->bytes_used;
4595         spin_unlock(&sinfo->lock);
4596
4597         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4598         spin_lock(&sinfo->lock);
4599         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4600                 data_used = 0;
4601         meta_used = sinfo->bytes_used;
4602         spin_unlock(&sinfo->lock);
4603
4604         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4605                     csum_size * 2;
4606         num_bytes += div64_u64(data_used + meta_used, 50);
4607
4608         if (num_bytes * 3 > meta_used)
4609                 num_bytes = div64_u64(meta_used, 3);
4610
4611         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4612 }
4613
4614 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4615 {
4616         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4617         struct btrfs_space_info *sinfo = block_rsv->space_info;
4618         u64 num_bytes;
4619
4620         num_bytes = calc_global_metadata_size(fs_info);
4621
4622         spin_lock(&sinfo->lock);
4623         spin_lock(&block_rsv->lock);
4624
4625         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4626
4627         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4628                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4629                     sinfo->bytes_may_use;
4630
4631         if (sinfo->total_bytes > num_bytes) {
4632                 num_bytes = sinfo->total_bytes - num_bytes;
4633                 block_rsv->reserved += num_bytes;
4634                 sinfo->bytes_may_use += num_bytes;
4635                 trace_btrfs_space_reservation(fs_info, "space_info",
4636                                       sinfo->flags, num_bytes, 1);
4637         }
4638
4639         if (block_rsv->reserved >= block_rsv->size) {
4640                 num_bytes = block_rsv->reserved - block_rsv->size;
4641                 sinfo->bytes_may_use -= num_bytes;
4642                 trace_btrfs_space_reservation(fs_info, "space_info",
4643                                       sinfo->flags, num_bytes, 0);
4644                 block_rsv->reserved = block_rsv->size;
4645                 block_rsv->full = 1;
4646         }
4647
4648         spin_unlock(&block_rsv->lock);
4649         spin_unlock(&sinfo->lock);
4650 }
4651
4652 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4653 {
4654         struct btrfs_space_info *space_info;
4655
4656         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4657         fs_info->chunk_block_rsv.space_info = space_info;
4658
4659         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4660         fs_info->global_block_rsv.space_info = space_info;
4661         fs_info->delalloc_block_rsv.space_info = space_info;
4662         fs_info->trans_block_rsv.space_info = space_info;
4663         fs_info->empty_block_rsv.space_info = space_info;
4664         fs_info->delayed_block_rsv.space_info = space_info;
4665
4666         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4667         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4668         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4669         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4670         if (fs_info->quota_root)
4671                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4672         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4673
4674         update_global_block_rsv(fs_info);
4675 }
4676
4677 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4678 {
4679         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4680                                 (u64)-1);
4681         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4682         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4683         WARN_ON(fs_info->trans_block_rsv.size > 0);
4684         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4685         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4686         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4687         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4688         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4689 }
4690
4691 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4692                                   struct btrfs_root *root)
4693 {
4694         if (!trans->block_rsv)
4695                 return;
4696
4697         if (!trans->bytes_reserved)
4698                 return;
4699
4700         trace_btrfs_space_reservation(root->fs_info, "transaction",
4701                                       trans->transid, trans->bytes_reserved, 0);
4702         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4703         trans->bytes_reserved = 0;
4704 }
4705
4706 /* Can only return 0 or -ENOSPC */
4707 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4708                                   struct inode *inode)
4709 {
4710         struct btrfs_root *root = BTRFS_I(inode)->root;
4711         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4712         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4713
4714         /*
4715          * We need to hold space in order to delete our orphan item once we've
4716          * added it, so this takes the reservation so we can release it later
4717          * when we are truly done with the orphan item.
4718          */
4719         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4720         trace_btrfs_space_reservation(root->fs_info, "orphan",
4721                                       btrfs_ino(inode), num_bytes, 1);
4722         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4723 }
4724
4725 void btrfs_orphan_release_metadata(struct inode *inode)
4726 {
4727         struct btrfs_root *root = BTRFS_I(inode)->root;
4728         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4729         trace_btrfs_space_reservation(root->fs_info, "orphan",
4730                                       btrfs_ino(inode), num_bytes, 0);
4731         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4732 }
4733
4734 /*
4735  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4736  * root: the root of the parent directory
4737  * rsv: block reservation
4738  * items: the number of items that we need do reservation
4739  * qgroup_reserved: used to return the reserved size in qgroup
4740  *
4741  * This function is used to reserve the space for snapshot/subvolume
4742  * creation and deletion. Those operations are different with the
4743  * common file/directory operations, they change two fs/file trees
4744  * and root tree, the number of items that the qgroup reserves is
4745  * different with the free space reservation. So we can not use
4746  * the space reseravtion mechanism in start_transaction().
4747  */
4748 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4749                                      struct btrfs_block_rsv *rsv,
4750                                      int items,
4751                                      u64 *qgroup_reserved,
4752                                      bool use_global_rsv)
4753 {
4754         u64 num_bytes;
4755         int ret;
4756         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4757
4758         if (root->fs_info->quota_enabled) {
4759                 /* One for parent inode, two for dir entries */
4760                 num_bytes = 3 * root->leafsize;
4761                 ret = btrfs_qgroup_reserve(root, num_bytes);
4762                 if (ret)
4763                         return ret;
4764         } else {
4765                 num_bytes = 0;
4766         }
4767
4768         *qgroup_reserved = num_bytes;
4769
4770         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4771         rsv->space_info = __find_space_info(root->fs_info,
4772                                             BTRFS_BLOCK_GROUP_METADATA);
4773         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4774                                   BTRFS_RESERVE_FLUSH_ALL);
4775
4776         if (ret == -ENOSPC && use_global_rsv)
4777                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
4778
4779         if (ret) {
4780                 if (*qgroup_reserved)
4781                         btrfs_qgroup_free(root, *qgroup_reserved);
4782         }
4783
4784         return ret;
4785 }
4786
4787 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4788                                       struct btrfs_block_rsv *rsv,
4789                                       u64 qgroup_reserved)
4790 {
4791         btrfs_block_rsv_release(root, rsv, (u64)-1);
4792         if (qgroup_reserved)
4793                 btrfs_qgroup_free(root, qgroup_reserved);
4794 }
4795
4796 /**
4797  * drop_outstanding_extent - drop an outstanding extent
4798  * @inode: the inode we're dropping the extent for
4799  *
4800  * This is called when we are freeing up an outstanding extent, either called
4801  * after an error or after an extent is written.  This will return the number of
4802  * reserved extents that need to be freed.  This must be called with
4803  * BTRFS_I(inode)->lock held.
4804  */
4805 static unsigned drop_outstanding_extent(struct inode *inode)
4806 {
4807         unsigned drop_inode_space = 0;
4808         unsigned dropped_extents = 0;
4809
4810         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4811         BTRFS_I(inode)->outstanding_extents--;
4812
4813         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4814             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4815                                &BTRFS_I(inode)->runtime_flags))
4816                 drop_inode_space = 1;
4817
4818         /*
4819          * If we have more or the same amount of outsanding extents than we have
4820          * reserved then we need to leave the reserved extents count alone.
4821          */
4822         if (BTRFS_I(inode)->outstanding_extents >=
4823             BTRFS_I(inode)->reserved_extents)
4824                 return drop_inode_space;
4825
4826         dropped_extents = BTRFS_I(inode)->reserved_extents -
4827                 BTRFS_I(inode)->outstanding_extents;
4828         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4829         return dropped_extents + drop_inode_space;
4830 }
4831
4832 /**
4833  * calc_csum_metadata_size - return the amount of metada space that must be
4834  *      reserved/free'd for the given bytes.
4835  * @inode: the inode we're manipulating
4836  * @num_bytes: the number of bytes in question
4837  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4838  *
4839  * This adjusts the number of csum_bytes in the inode and then returns the
4840  * correct amount of metadata that must either be reserved or freed.  We
4841  * calculate how many checksums we can fit into one leaf and then divide the
4842  * number of bytes that will need to be checksumed by this value to figure out
4843  * how many checksums will be required.  If we are adding bytes then the number
4844  * may go up and we will return the number of additional bytes that must be
4845  * reserved.  If it is going down we will return the number of bytes that must
4846  * be freed.
4847  *
4848  * This must be called with BTRFS_I(inode)->lock held.
4849  */
4850 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4851                                    int reserve)
4852 {
4853         struct btrfs_root *root = BTRFS_I(inode)->root;
4854         u64 csum_size;
4855         int num_csums_per_leaf;
4856         int num_csums;
4857         int old_csums;
4858
4859         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4860             BTRFS_I(inode)->csum_bytes == 0)
4861                 return 0;
4862
4863         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4864         if (reserve)
4865                 BTRFS_I(inode)->csum_bytes += num_bytes;
4866         else
4867                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4868         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4869         num_csums_per_leaf = (int)div64_u64(csum_size,
4870                                             sizeof(struct btrfs_csum_item) +
4871                                             sizeof(struct btrfs_disk_key));
4872         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4873         num_csums = num_csums + num_csums_per_leaf - 1;
4874         num_csums = num_csums / num_csums_per_leaf;
4875
4876         old_csums = old_csums + num_csums_per_leaf - 1;
4877         old_csums = old_csums / num_csums_per_leaf;
4878
4879         /* No change, no need to reserve more */
4880         if (old_csums == num_csums)
4881                 return 0;
4882
4883         if (reserve)
4884                 return btrfs_calc_trans_metadata_size(root,
4885                                                       num_csums - old_csums);
4886
4887         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4888 }
4889
4890 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4891 {
4892         struct btrfs_root *root = BTRFS_I(inode)->root;
4893         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4894         u64 to_reserve = 0;
4895         u64 csum_bytes;
4896         unsigned nr_extents = 0;
4897         int extra_reserve = 0;
4898         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
4899         int ret = 0;
4900         bool delalloc_lock = true;
4901         u64 to_free = 0;
4902         unsigned dropped;
4903
4904         /* If we are a free space inode we need to not flush since we will be in
4905          * the middle of a transaction commit.  We also don't need the delalloc
4906          * mutex since we won't race with anybody.  We need this mostly to make
4907          * lockdep shut its filthy mouth.
4908          */
4909         if (btrfs_is_free_space_inode(inode)) {
4910                 flush = BTRFS_RESERVE_NO_FLUSH;
4911                 delalloc_lock = false;
4912         }
4913
4914         if (flush != BTRFS_RESERVE_NO_FLUSH &&
4915             btrfs_transaction_in_commit(root->fs_info))
4916                 schedule_timeout(1);
4917
4918         if (delalloc_lock)
4919                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4920
4921         num_bytes = ALIGN(num_bytes, root->sectorsize);
4922
4923         spin_lock(&BTRFS_I(inode)->lock);
4924         BTRFS_I(inode)->outstanding_extents++;
4925
4926         if (BTRFS_I(inode)->outstanding_extents >
4927             BTRFS_I(inode)->reserved_extents)
4928                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4929                         BTRFS_I(inode)->reserved_extents;
4930
4931         /*
4932          * Add an item to reserve for updating the inode when we complete the
4933          * delalloc io.
4934          */
4935         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4936                       &BTRFS_I(inode)->runtime_flags)) {
4937                 nr_extents++;
4938                 extra_reserve = 1;
4939         }
4940
4941         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4942         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4943         csum_bytes = BTRFS_I(inode)->csum_bytes;
4944         spin_unlock(&BTRFS_I(inode)->lock);
4945
4946         if (root->fs_info->quota_enabled) {
4947                 ret = btrfs_qgroup_reserve(root, num_bytes +
4948                                            nr_extents * root->leafsize);
4949                 if (ret)
4950                         goto out_fail;
4951         }
4952
4953         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4954         if (unlikely(ret)) {
4955                 if (root->fs_info->quota_enabled)
4956                         btrfs_qgroup_free(root, num_bytes +
4957                                                 nr_extents * root->leafsize);
4958                 goto out_fail;
4959         }
4960
4961         spin_lock(&BTRFS_I(inode)->lock);
4962         if (extra_reserve) {
4963                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4964                         &BTRFS_I(inode)->runtime_flags);
4965                 nr_extents--;
4966         }
4967         BTRFS_I(inode)->reserved_extents += nr_extents;
4968         spin_unlock(&BTRFS_I(inode)->lock);
4969
4970         if (delalloc_lock)
4971                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4972
4973         if (to_reserve)
4974                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
4975                                               btrfs_ino(inode), to_reserve, 1);
4976         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4977
4978         return 0;
4979
4980 out_fail:
4981         spin_lock(&BTRFS_I(inode)->lock);
4982         dropped = drop_outstanding_extent(inode);
4983         /*
4984          * If the inodes csum_bytes is the same as the original
4985          * csum_bytes then we know we haven't raced with any free()ers
4986          * so we can just reduce our inodes csum bytes and carry on.
4987          */
4988         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
4989                 calc_csum_metadata_size(inode, num_bytes, 0);
4990         } else {
4991                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
4992                 u64 bytes;
4993
4994                 /*
4995                  * This is tricky, but first we need to figure out how much we
4996                  * free'd from any free-ers that occured during this
4997                  * reservation, so we reset ->csum_bytes to the csum_bytes
4998                  * before we dropped our lock, and then call the free for the
4999                  * number of bytes that were freed while we were trying our
5000                  * reservation.
5001                  */
5002                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5003                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5004                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5005
5006
5007                 /*
5008                  * Now we need to see how much we would have freed had we not
5009                  * been making this reservation and our ->csum_bytes were not
5010                  * artificially inflated.
5011                  */
5012                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5013                 bytes = csum_bytes - orig_csum_bytes;
5014                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5015
5016                 /*
5017                  * Now reset ->csum_bytes to what it should be.  If bytes is
5018                  * more than to_free then we would have free'd more space had we
5019                  * not had an artificially high ->csum_bytes, so we need to free
5020                  * the remainder.  If bytes is the same or less then we don't
5021                  * need to do anything, the other free-ers did the correct
5022                  * thing.
5023                  */
5024                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5025                 if (bytes > to_free)
5026                         to_free = bytes - to_free;
5027                 else
5028                         to_free = 0;
5029         }
5030         spin_unlock(&BTRFS_I(inode)->lock);
5031         if (dropped)
5032                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5033
5034         if (to_free) {
5035                 btrfs_block_rsv_release(root, block_rsv, to_free);
5036                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5037                                               btrfs_ino(inode), to_free, 0);
5038         }
5039         if (delalloc_lock)
5040                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5041         return ret;
5042 }
5043
5044 /**
5045  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5046  * @inode: the inode to release the reservation for
5047  * @num_bytes: the number of bytes we're releasing
5048  *
5049  * This will release the metadata reservation for an inode.  This can be called
5050  * once we complete IO for a given set of bytes to release their metadata
5051  * reservations.
5052  */
5053 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5054 {
5055         struct btrfs_root *root = BTRFS_I(inode)->root;
5056         u64 to_free = 0;
5057         unsigned dropped;
5058
5059         num_bytes = ALIGN(num_bytes, root->sectorsize);
5060         spin_lock(&BTRFS_I(inode)->lock);
5061         dropped = drop_outstanding_extent(inode);
5062
5063         if (num_bytes)
5064                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5065         spin_unlock(&BTRFS_I(inode)->lock);
5066         if (dropped > 0)
5067                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5068
5069         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5070                                       btrfs_ino(inode), to_free, 0);
5071         if (root->fs_info->quota_enabled) {
5072                 btrfs_qgroup_free(root, num_bytes +
5073                                         dropped * root->leafsize);
5074         }
5075
5076         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5077                                 to_free);
5078 }
5079
5080 /**
5081  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5082  * @inode: inode we're writing to
5083  * @num_bytes: the number of bytes we want to allocate
5084  *
5085  * This will do the following things
5086  *
5087  * o reserve space in the data space info for num_bytes
5088  * o reserve space in the metadata space info based on number of outstanding
5089  *   extents and how much csums will be needed
5090  * o add to the inodes ->delalloc_bytes
5091  * o add it to the fs_info's delalloc inodes list.
5092  *
5093  * This will return 0 for success and -ENOSPC if there is no space left.
5094  */
5095 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5096 {
5097         int ret;
5098
5099         ret = btrfs_check_data_free_space(inode, num_bytes);
5100         if (ret)
5101                 return ret;
5102
5103         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5104         if (ret) {
5105                 btrfs_free_reserved_data_space(inode, num_bytes);
5106                 return ret;
5107         }
5108
5109         return 0;
5110 }
5111
5112 /**
5113  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5114  * @inode: inode we're releasing space for
5115  * @num_bytes: the number of bytes we want to free up
5116  *
5117  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5118  * called in the case that we don't need the metadata AND data reservations
5119  * anymore.  So if there is an error or we insert an inline extent.
5120  *
5121  * This function will release the metadata space that was not used and will
5122  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5123  * list if there are no delalloc bytes left.
5124  */
5125 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5126 {
5127         btrfs_delalloc_release_metadata(inode, num_bytes);
5128         btrfs_free_reserved_data_space(inode, num_bytes);
5129 }
5130
5131 static int update_block_group(struct btrfs_root *root,
5132                               u64 bytenr, u64 num_bytes, int alloc)
5133 {
5134         struct btrfs_block_group_cache *cache = NULL;
5135         struct btrfs_fs_info *info = root->fs_info;
5136         u64 total = num_bytes;
5137         u64 old_val;
5138         u64 byte_in_group;
5139         int factor;
5140
5141         /* block accounting for super block */
5142         spin_lock(&info->delalloc_root_lock);
5143         old_val = btrfs_super_bytes_used(info->super_copy);
5144         if (alloc)
5145                 old_val += num_bytes;
5146         else
5147                 old_val -= num_bytes;
5148         btrfs_set_super_bytes_used(info->super_copy, old_val);
5149         spin_unlock(&info->delalloc_root_lock);
5150
5151         while (total) {
5152                 cache = btrfs_lookup_block_group(info, bytenr);
5153                 if (!cache)
5154                         return -ENOENT;
5155                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5156                                     BTRFS_BLOCK_GROUP_RAID1 |
5157                                     BTRFS_BLOCK_GROUP_RAID10))
5158                         factor = 2;
5159                 else
5160                         factor = 1;
5161                 /*
5162                  * If this block group has free space cache written out, we
5163                  * need to make sure to load it if we are removing space.  This
5164                  * is because we need the unpinning stage to actually add the
5165                  * space back to the block group, otherwise we will leak space.
5166                  */
5167                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5168                         cache_block_group(cache, 1);
5169
5170                 byte_in_group = bytenr - cache->key.objectid;
5171                 WARN_ON(byte_in_group > cache->key.offset);
5172
5173                 spin_lock(&cache->space_info->lock);
5174                 spin_lock(&cache->lock);
5175
5176                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5177                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5178                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5179
5180                 cache->dirty = 1;
5181                 old_val = btrfs_block_group_used(&cache->item);
5182                 num_bytes = min(total, cache->key.offset - byte_in_group);
5183                 if (alloc) {
5184                         old_val += num_bytes;
5185                         btrfs_set_block_group_used(&cache->item, old_val);
5186                         cache->reserved -= num_bytes;
5187                         cache->space_info->bytes_reserved -= num_bytes;
5188                         cache->space_info->bytes_used += num_bytes;
5189                         cache->space_info->disk_used += num_bytes * factor;
5190                         spin_unlock(&cache->lock);
5191                         spin_unlock(&cache->space_info->lock);
5192                 } else {
5193                         old_val -= num_bytes;
5194                         btrfs_set_block_group_used(&cache->item, old_val);
5195                         cache->pinned += num_bytes;
5196                         cache->space_info->bytes_pinned += num_bytes;
5197                         cache->space_info->bytes_used -= num_bytes;
5198                         cache->space_info->disk_used -= num_bytes * factor;
5199                         spin_unlock(&cache->lock);
5200                         spin_unlock(&cache->space_info->lock);
5201
5202                         set_extent_dirty(info->pinned_extents,
5203                                          bytenr, bytenr + num_bytes - 1,
5204                                          GFP_NOFS | __GFP_NOFAIL);
5205                 }
5206                 btrfs_put_block_group(cache);
5207                 total -= num_bytes;
5208                 bytenr += num_bytes;
5209         }
5210         return 0;
5211 }
5212
5213 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5214 {
5215         struct btrfs_block_group_cache *cache;
5216         u64 bytenr;
5217
5218         spin_lock(&root->fs_info->block_group_cache_lock);
5219         bytenr = root->fs_info->first_logical_byte;
5220         spin_unlock(&root->fs_info->block_group_cache_lock);
5221
5222         if (bytenr < (u64)-1)
5223                 return bytenr;
5224
5225         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5226         if (!cache)
5227                 return 0;
5228
5229         bytenr = cache->key.objectid;
5230         btrfs_put_block_group(cache);
5231
5232         return bytenr;
5233 }
5234
5235 static int pin_down_extent(struct btrfs_root *root,
5236                            struct btrfs_block_group_cache *cache,
5237                            u64 bytenr, u64 num_bytes, int reserved)
5238 {
5239         spin_lock(&cache->space_info->lock);
5240         spin_lock(&cache->lock);
5241         cache->pinned += num_bytes;
5242         cache->space_info->bytes_pinned += num_bytes;
5243         if (reserved) {
5244                 cache->reserved -= num_bytes;
5245                 cache->space_info->bytes_reserved -= num_bytes;
5246         }
5247         spin_unlock(&cache->lock);
5248         spin_unlock(&cache->space_info->lock);
5249
5250         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5251                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5252         if (reserved)
5253                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5254         return 0;
5255 }
5256
5257 /*
5258  * this function must be called within transaction
5259  */
5260 int btrfs_pin_extent(struct btrfs_root *root,
5261                      u64 bytenr, u64 num_bytes, int reserved)
5262 {
5263         struct btrfs_block_group_cache *cache;
5264
5265         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5266         BUG_ON(!cache); /* Logic error */
5267
5268         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5269
5270         btrfs_put_block_group(cache);
5271         return 0;
5272 }
5273
5274 /*
5275  * this function must be called within transaction
5276  */
5277 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5278                                     u64 bytenr, u64 num_bytes)
5279 {
5280         struct btrfs_block_group_cache *cache;
5281         int ret;
5282
5283         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5284         if (!cache)
5285                 return -EINVAL;
5286
5287         /*
5288          * pull in the free space cache (if any) so that our pin
5289          * removes the free space from the cache.  We have load_only set
5290          * to one because the slow code to read in the free extents does check
5291          * the pinned extents.
5292          */
5293         cache_block_group(cache, 1);
5294
5295         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5296
5297         /* remove us from the free space cache (if we're there at all) */
5298         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5299         btrfs_put_block_group(cache);
5300         return ret;
5301 }
5302
5303 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5304 {
5305         int ret;
5306         struct btrfs_block_group_cache *block_group;
5307         struct btrfs_caching_control *caching_ctl;
5308
5309         block_group = btrfs_lookup_block_group(root->fs_info, start);
5310         if (!block_group)
5311                 return -EINVAL;
5312
5313         cache_block_group(block_group, 0);
5314         caching_ctl = get_caching_control(block_group);
5315
5316         if (!caching_ctl) {
5317                 /* Logic error */
5318                 BUG_ON(!block_group_cache_done(block_group));
5319                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5320         } else {
5321                 mutex_lock(&caching_ctl->mutex);
5322
5323                 if (start >= caching_ctl->progress) {
5324                         ret = add_excluded_extent(root, start, num_bytes);
5325                 } else if (start + num_bytes <= caching_ctl->progress) {
5326                         ret = btrfs_remove_free_space(block_group,
5327                                                       start, num_bytes);
5328                 } else {
5329                         num_bytes = caching_ctl->progress - start;
5330                         ret = btrfs_remove_free_space(block_group,
5331                                                       start, num_bytes);
5332                         if (ret)
5333                                 goto out_lock;
5334
5335                         num_bytes = (start + num_bytes) -
5336                                 caching_ctl->progress;
5337                         start = caching_ctl->progress;
5338                         ret = add_excluded_extent(root, start, num_bytes);
5339                 }
5340 out_lock:
5341                 mutex_unlock(&caching_ctl->mutex);
5342                 put_caching_control(caching_ctl);
5343         }
5344         btrfs_put_block_group(block_group);
5345         return ret;
5346 }
5347
5348 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5349                                  struct extent_buffer *eb)
5350 {
5351         struct btrfs_file_extent_item *item;
5352         struct btrfs_key key;
5353         int found_type;
5354         int i;
5355
5356         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5357                 return 0;
5358
5359         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5360                 btrfs_item_key_to_cpu(eb, &key, i);
5361                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5362                         continue;
5363                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5364                 found_type = btrfs_file_extent_type(eb, item);
5365                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5366                         continue;
5367                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5368                         continue;
5369                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5370                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5371                 __exclude_logged_extent(log, key.objectid, key.offset);
5372         }
5373
5374         return 0;
5375 }
5376
5377 /**
5378  * btrfs_update_reserved_bytes - update the block_group and space info counters
5379  * @cache:      The cache we are manipulating
5380  * @num_bytes:  The number of bytes in question
5381  * @reserve:    One of the reservation enums
5382  *
5383  * This is called by the allocator when it reserves space, or by somebody who is
5384  * freeing space that was never actually used on disk.  For example if you
5385  * reserve some space for a new leaf in transaction A and before transaction A
5386  * commits you free that leaf, you call this with reserve set to 0 in order to
5387  * clear the reservation.
5388  *
5389  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5390  * ENOSPC accounting.  For data we handle the reservation through clearing the
5391  * delalloc bits in the io_tree.  We have to do this since we could end up
5392  * allocating less disk space for the amount of data we have reserved in the
5393  * case of compression.
5394  *
5395  * If this is a reservation and the block group has become read only we cannot
5396  * make the reservation and return -EAGAIN, otherwise this function always
5397  * succeeds.
5398  */
5399 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5400                                        u64 num_bytes, int reserve)
5401 {
5402         struct btrfs_space_info *space_info = cache->space_info;
5403         int ret = 0;
5404
5405         spin_lock(&space_info->lock);
5406         spin_lock(&cache->lock);
5407         if (reserve != RESERVE_FREE) {
5408                 if (cache->ro) {
5409                         ret = -EAGAIN;
5410                 } else {
5411                         cache->reserved += num_bytes;
5412                         space_info->bytes_reserved += num_bytes;
5413                         if (reserve == RESERVE_ALLOC) {
5414                                 trace_btrfs_space_reservation(cache->fs_info,
5415                                                 "space_info", space_info->flags,
5416                                                 num_bytes, 0);
5417                                 space_info->bytes_may_use -= num_bytes;
5418                         }
5419                 }
5420         } else {
5421                 if (cache->ro)
5422                         space_info->bytes_readonly += num_bytes;
5423                 cache->reserved -= num_bytes;
5424                 space_info->bytes_reserved -= num_bytes;
5425         }
5426         spin_unlock(&cache->lock);
5427         spin_unlock(&space_info->lock);
5428         return ret;
5429 }
5430
5431 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5432                                 struct btrfs_root *root)
5433 {
5434         struct btrfs_fs_info *fs_info = root->fs_info;
5435         struct btrfs_caching_control *next;
5436         struct btrfs_caching_control *caching_ctl;
5437         struct btrfs_block_group_cache *cache;
5438         struct btrfs_space_info *space_info;
5439
5440         down_write(&fs_info->extent_commit_sem);
5441
5442         list_for_each_entry_safe(caching_ctl, next,
5443                                  &fs_info->caching_block_groups, list) {
5444                 cache = caching_ctl->block_group;
5445                 if (block_group_cache_done(cache)) {
5446                         cache->last_byte_to_unpin = (u64)-1;
5447                         list_del_init(&caching_ctl->list);
5448                         put_caching_control(caching_ctl);
5449                 } else {
5450                         cache->last_byte_to_unpin = caching_ctl->progress;
5451                 }
5452         }
5453
5454         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5455                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5456         else
5457                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5458
5459         up_write(&fs_info->extent_commit_sem);
5460
5461         list_for_each_entry_rcu(space_info, &fs_info->space_info, list)
5462                 percpu_counter_set(&space_info->total_bytes_pinned, 0);
5463
5464         update_global_block_rsv(fs_info);
5465 }
5466
5467 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5468 {
5469         struct btrfs_fs_info *fs_info = root->fs_info;
5470         struct btrfs_block_group_cache *cache = NULL;
5471         struct btrfs_space_info *space_info;
5472         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5473         u64 len;
5474         bool readonly;
5475
5476         while (start <= end) {
5477                 readonly = false;
5478                 if (!cache ||
5479                     start >= cache->key.objectid + cache->key.offset) {
5480                         if (cache)
5481                                 btrfs_put_block_group(cache);
5482                         cache = btrfs_lookup_block_group(fs_info, start);
5483                         BUG_ON(!cache); /* Logic error */
5484                 }
5485
5486                 len = cache->key.objectid + cache->key.offset - start;
5487                 len = min(len, end + 1 - start);
5488
5489                 if (start < cache->last_byte_to_unpin) {
5490                         len = min(len, cache->last_byte_to_unpin - start);
5491                         btrfs_add_free_space(cache, start, len);
5492                 }
5493
5494                 start += len;
5495                 space_info = cache->space_info;
5496
5497                 spin_lock(&space_info->lock);
5498                 spin_lock(&cache->lock);
5499                 cache->pinned -= len;
5500                 space_info->bytes_pinned -= len;
5501                 if (cache->ro) {
5502                         space_info->bytes_readonly += len;
5503                         readonly = true;
5504                 }
5505                 spin_unlock(&cache->lock);
5506                 if (!readonly && global_rsv->space_info == space_info) {
5507                         spin_lock(&global_rsv->lock);
5508                         if (!global_rsv->full) {
5509                                 len = min(len, global_rsv->size -
5510                                           global_rsv->reserved);
5511                                 global_rsv->reserved += len;
5512                                 space_info->bytes_may_use += len;
5513                                 if (global_rsv->reserved >= global_rsv->size)
5514                                         global_rsv->full = 1;
5515                         }
5516                         spin_unlock(&global_rsv->lock);
5517                 }
5518                 spin_unlock(&space_info->lock);
5519         }
5520
5521         if (cache)
5522                 btrfs_put_block_group(cache);
5523         return 0;
5524 }
5525
5526 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5527                                struct btrfs_root *root)
5528 {
5529         struct btrfs_fs_info *fs_info = root->fs_info;
5530         struct extent_io_tree *unpin;
5531         u64 start;
5532         u64 end;
5533         int ret;
5534
5535         if (trans->aborted)
5536                 return 0;
5537
5538         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5539                 unpin = &fs_info->freed_extents[1];
5540         else
5541                 unpin = &fs_info->freed_extents[0];
5542
5543         while (1) {
5544                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5545                                             EXTENT_DIRTY, NULL);
5546                 if (ret)
5547                         break;
5548
5549                 if (btrfs_test_opt(root, DISCARD))
5550                         ret = btrfs_discard_extent(root, start,
5551                                                    end + 1 - start, NULL);
5552
5553                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5554                 unpin_extent_range(root, start, end);
5555                 cond_resched();
5556         }
5557
5558         return 0;
5559 }
5560
5561 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
5562                              u64 owner, u64 root_objectid)
5563 {
5564         struct btrfs_space_info *space_info;
5565         u64 flags;
5566
5567         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5568                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
5569                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
5570                 else
5571                         flags = BTRFS_BLOCK_GROUP_METADATA;
5572         } else {
5573                 flags = BTRFS_BLOCK_GROUP_DATA;
5574         }
5575
5576         space_info = __find_space_info(fs_info, flags);
5577         BUG_ON(!space_info); /* Logic bug */
5578         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
5579 }
5580
5581
5582 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5583                                 struct btrfs_root *root,
5584                                 u64 bytenr, u64 num_bytes, u64 parent,
5585                                 u64 root_objectid, u64 owner_objectid,
5586                                 u64 owner_offset, int refs_to_drop,
5587                                 struct btrfs_delayed_extent_op *extent_op)
5588 {
5589         struct btrfs_key key;
5590         struct btrfs_path *path;
5591         struct btrfs_fs_info *info = root->fs_info;
5592         struct btrfs_root *extent_root = info->extent_root;
5593         struct extent_buffer *leaf;
5594         struct btrfs_extent_item *ei;
5595         struct btrfs_extent_inline_ref *iref;
5596         int ret;
5597         int is_data;
5598         int extent_slot = 0;
5599         int found_extent = 0;
5600         int num_to_del = 1;
5601         u32 item_size;
5602         u64 refs;
5603         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5604                                                  SKINNY_METADATA);
5605
5606         path = btrfs_alloc_path();
5607         if (!path)
5608                 return -ENOMEM;
5609
5610         path->reada = 1;
5611         path->leave_spinning = 1;
5612
5613         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5614         BUG_ON(!is_data && refs_to_drop != 1);
5615
5616         if (is_data)
5617                 skinny_metadata = 0;
5618
5619         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5620                                     bytenr, num_bytes, parent,
5621                                     root_objectid, owner_objectid,
5622                                     owner_offset);
5623         if (ret == 0) {
5624                 extent_slot = path->slots[0];
5625                 while (extent_slot >= 0) {
5626                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5627                                               extent_slot);
5628                         if (key.objectid != bytenr)
5629                                 break;
5630                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5631                             key.offset == num_bytes) {
5632                                 found_extent = 1;
5633                                 break;
5634                         }
5635                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5636                             key.offset == owner_objectid) {
5637                                 found_extent = 1;
5638                                 break;
5639                         }
5640                         if (path->slots[0] - extent_slot > 5)
5641                                 break;
5642                         extent_slot--;
5643                 }
5644 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5645                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5646                 if (found_extent && item_size < sizeof(*ei))
5647                         found_extent = 0;
5648 #endif
5649                 if (!found_extent) {
5650                         BUG_ON(iref);
5651                         ret = remove_extent_backref(trans, extent_root, path,
5652                                                     NULL, refs_to_drop,
5653                                                     is_data);
5654                         if (ret) {
5655                                 btrfs_abort_transaction(trans, extent_root, ret);
5656                                 goto out;
5657                         }
5658                         btrfs_release_path(path);
5659                         path->leave_spinning = 1;
5660
5661                         key.objectid = bytenr;
5662                         key.type = BTRFS_EXTENT_ITEM_KEY;
5663                         key.offset = num_bytes;
5664
5665                         if (!is_data && skinny_metadata) {
5666                                 key.type = BTRFS_METADATA_ITEM_KEY;
5667                                 key.offset = owner_objectid;
5668                         }
5669
5670                         ret = btrfs_search_slot(trans, extent_root,
5671                                                 &key, path, -1, 1);
5672                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5673                                 /*
5674                                  * Couldn't find our skinny metadata item,
5675                                  * see if we have ye olde extent item.
5676                                  */
5677                                 path->slots[0]--;
5678                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5679                                                       path->slots[0]);
5680                                 if (key.objectid == bytenr &&
5681                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5682                                     key.offset == num_bytes)
5683                                         ret = 0;
5684                         }
5685
5686                         if (ret > 0 && skinny_metadata) {
5687                                 skinny_metadata = false;
5688                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5689                                 key.offset = num_bytes;
5690                                 btrfs_release_path(path);
5691                                 ret = btrfs_search_slot(trans, extent_root,
5692                                                         &key, path, -1, 1);
5693                         }
5694
5695                         if (ret) {
5696                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5697                                         ret, bytenr);
5698                                 if (ret > 0)
5699                                         btrfs_print_leaf(extent_root,
5700                                                          path->nodes[0]);
5701                         }
5702                         if (ret < 0) {
5703                                 btrfs_abort_transaction(trans, extent_root, ret);
5704                                 goto out;
5705                         }
5706                         extent_slot = path->slots[0];
5707                 }
5708         } else if (WARN_ON(ret == -ENOENT)) {
5709                 btrfs_print_leaf(extent_root, path->nodes[0]);
5710                 btrfs_err(info,
5711                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5712                         bytenr, parent, root_objectid, owner_objectid,
5713                         owner_offset);
5714         } else {
5715                 btrfs_abort_transaction(trans, extent_root, ret);
5716                 goto out;
5717         }
5718
5719         leaf = path->nodes[0];
5720         item_size = btrfs_item_size_nr(leaf, extent_slot);
5721 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5722         if (item_size < sizeof(*ei)) {
5723                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5724                 ret = convert_extent_item_v0(trans, extent_root, path,
5725                                              owner_objectid, 0);
5726                 if (ret < 0) {
5727                         btrfs_abort_transaction(trans, extent_root, ret);
5728                         goto out;
5729                 }
5730
5731                 btrfs_release_path(path);
5732                 path->leave_spinning = 1;
5733
5734                 key.objectid = bytenr;
5735                 key.type = BTRFS_EXTENT_ITEM_KEY;
5736                 key.offset = num_bytes;
5737
5738                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5739                                         -1, 1);
5740                 if (ret) {
5741                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5742                                 ret, bytenr);
5743                         btrfs_print_leaf(extent_root, path->nodes[0]);
5744                 }
5745                 if (ret < 0) {
5746                         btrfs_abort_transaction(trans, extent_root, ret);
5747                         goto out;
5748                 }
5749
5750                 extent_slot = path->slots[0];
5751                 leaf = path->nodes[0];
5752                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5753         }
5754 #endif
5755         BUG_ON(item_size < sizeof(*ei));
5756         ei = btrfs_item_ptr(leaf, extent_slot,
5757                             struct btrfs_extent_item);
5758         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
5759             key.type == BTRFS_EXTENT_ITEM_KEY) {
5760                 struct btrfs_tree_block_info *bi;
5761                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5762                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5763                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5764         }
5765
5766         refs = btrfs_extent_refs(leaf, ei);
5767         if (refs < refs_to_drop) {
5768                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
5769                           "for bytenr %Lu\n", refs_to_drop, refs, bytenr);
5770                 ret = -EINVAL;
5771                 btrfs_abort_transaction(trans, extent_root, ret);
5772                 goto out;
5773         }
5774         refs -= refs_to_drop;
5775
5776         if (refs > 0) {
5777                 if (extent_op)
5778                         __run_delayed_extent_op(extent_op, leaf, ei);
5779                 /*
5780                  * In the case of inline back ref, reference count will
5781                  * be updated by remove_extent_backref
5782                  */
5783                 if (iref) {
5784                         BUG_ON(!found_extent);
5785                 } else {
5786                         btrfs_set_extent_refs(leaf, ei, refs);
5787                         btrfs_mark_buffer_dirty(leaf);
5788                 }
5789                 if (found_extent) {
5790                         ret = remove_extent_backref(trans, extent_root, path,
5791                                                     iref, refs_to_drop,
5792                                                     is_data);
5793                         if (ret) {
5794                                 btrfs_abort_transaction(trans, extent_root, ret);
5795                                 goto out;
5796                         }
5797                 }
5798                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
5799                                  root_objectid);
5800         } else {
5801                 if (found_extent) {
5802                         BUG_ON(is_data && refs_to_drop !=
5803                                extent_data_ref_count(root, path, iref));
5804                         if (iref) {
5805                                 BUG_ON(path->slots[0] != extent_slot);
5806                         } else {
5807                                 BUG_ON(path->slots[0] != extent_slot + 1);
5808                                 path->slots[0] = extent_slot;
5809                                 num_to_del = 2;
5810                         }
5811                 }
5812
5813                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5814                                       num_to_del);
5815                 if (ret) {
5816                         btrfs_abort_transaction(trans, extent_root, ret);
5817                         goto out;
5818                 }
5819                 btrfs_release_path(path);
5820
5821                 if (is_data) {
5822                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5823                         if (ret) {
5824                                 btrfs_abort_transaction(trans, extent_root, ret);
5825                                 goto out;
5826                         }
5827                 }
5828
5829                 ret = update_block_group(root, bytenr, num_bytes, 0);
5830                 if (ret) {
5831                         btrfs_abort_transaction(trans, extent_root, ret);
5832                         goto out;
5833                 }
5834         }
5835 out:
5836         btrfs_free_path(path);
5837         return ret;
5838 }
5839
5840 /*
5841  * when we free an block, it is possible (and likely) that we free the last
5842  * delayed ref for that extent as well.  This searches the delayed ref tree for
5843  * a given extent, and if there are no other delayed refs to be processed, it
5844  * removes it from the tree.
5845  */
5846 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5847                                       struct btrfs_root *root, u64 bytenr)
5848 {
5849         struct btrfs_delayed_ref_head *head;
5850         struct btrfs_delayed_ref_root *delayed_refs;
5851         int ret = 0;
5852
5853         delayed_refs = &trans->transaction->delayed_refs;
5854         spin_lock(&delayed_refs->lock);
5855         head = btrfs_find_delayed_ref_head(trans, bytenr);
5856         if (!head)
5857                 goto out;
5858
5859         spin_lock(&head->lock);
5860         if (rb_first(&head->ref_root))
5861                 goto out;
5862
5863         if (head->extent_op) {
5864                 if (!head->must_insert_reserved)
5865                         goto out;
5866                 btrfs_free_delayed_extent_op(head->extent_op);
5867                 head->extent_op = NULL;
5868         }
5869
5870         /*
5871          * waiting for the lock here would deadlock.  If someone else has it
5872          * locked they are already in the process of dropping it anyway
5873          */
5874         if (!mutex_trylock(&head->mutex))
5875                 goto out;
5876
5877         /*
5878          * at this point we have a head with no other entries.  Go
5879          * ahead and process it.
5880          */
5881         head->node.in_tree = 0;
5882         rb_erase(&head->href_node, &delayed_refs->href_root);
5883
5884         atomic_dec(&delayed_refs->num_entries);
5885
5886         /*
5887          * we don't take a ref on the node because we're removing it from the
5888          * tree, so we just steal the ref the tree was holding.
5889          */
5890         delayed_refs->num_heads--;
5891         if (head->processing == 0)
5892                 delayed_refs->num_heads_ready--;
5893         head->processing = 0;
5894         spin_unlock(&head->lock);
5895         spin_unlock(&delayed_refs->lock);
5896
5897         BUG_ON(head->extent_op);
5898         if (head->must_insert_reserved)
5899                 ret = 1;
5900
5901         mutex_unlock(&head->mutex);
5902         btrfs_put_delayed_ref(&head->node);
5903         return ret;
5904 out:
5905         spin_unlock(&head->lock);
5906         spin_unlock(&delayed_refs->lock);
5907         return 0;
5908 }
5909
5910 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5911                            struct btrfs_root *root,
5912                            struct extent_buffer *buf,
5913                            u64 parent, int last_ref)
5914 {
5915         struct btrfs_block_group_cache *cache = NULL;
5916         int pin = 1;
5917         int ret;
5918
5919         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5920                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5921                                         buf->start, buf->len,
5922                                         parent, root->root_key.objectid,
5923                                         btrfs_header_level(buf),
5924                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5925                 BUG_ON(ret); /* -ENOMEM */
5926         }
5927
5928         if (!last_ref)
5929                 return;
5930
5931         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5932
5933         if (btrfs_header_generation(buf) == trans->transid) {
5934                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5935                         ret = check_ref_cleanup(trans, root, buf->start);
5936                         if (!ret)
5937                                 goto out;
5938                 }
5939
5940                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5941                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5942                         goto out;
5943                 }
5944
5945                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5946
5947                 btrfs_add_free_space(cache, buf->start, buf->len);
5948                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5949                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
5950                 pin = 0;
5951         }
5952 out:
5953         if (pin)
5954                 add_pinned_bytes(root->fs_info, buf->len,
5955                                  btrfs_header_level(buf),
5956                                  root->root_key.objectid);
5957
5958         /*
5959          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5960          * anymore.
5961          */
5962         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5963         btrfs_put_block_group(cache);
5964 }
5965
5966 /* Can return -ENOMEM */
5967 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5968                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5969                       u64 owner, u64 offset, int for_cow)
5970 {
5971         int ret;
5972         struct btrfs_fs_info *fs_info = root->fs_info;
5973
5974         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
5975
5976         /*
5977          * tree log blocks never actually go into the extent allocation
5978          * tree, just update pinning info and exit early.
5979          */
5980         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5981                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5982                 /* unlocks the pinned mutex */
5983                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5984                 ret = 0;
5985         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5986                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5987                                         num_bytes,
5988                                         parent, root_objectid, (int)owner,
5989                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5990         } else {
5991                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5992                                                 num_bytes,
5993                                                 parent, root_objectid, owner,
5994                                                 offset, BTRFS_DROP_DELAYED_REF,
5995                                                 NULL, for_cow);
5996         }
5997         return ret;
5998 }
5999
6000 static u64 stripe_align(struct btrfs_root *root,
6001                         struct btrfs_block_group_cache *cache,
6002                         u64 val, u64 num_bytes)
6003 {
6004         u64 ret = ALIGN(val, root->stripesize);
6005         return ret;
6006 }
6007
6008 /*
6009  * when we wait for progress in the block group caching, its because
6010  * our allocation attempt failed at least once.  So, we must sleep
6011  * and let some progress happen before we try again.
6012  *
6013  * This function will sleep at least once waiting for new free space to
6014  * show up, and then it will check the block group free space numbers
6015  * for our min num_bytes.  Another option is to have it go ahead
6016  * and look in the rbtree for a free extent of a given size, but this
6017  * is a good start.
6018  *
6019  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6020  * any of the information in this block group.
6021  */
6022 static noinline void
6023 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6024                                 u64 num_bytes)
6025 {
6026         struct btrfs_caching_control *caching_ctl;
6027
6028         caching_ctl = get_caching_control(cache);
6029         if (!caching_ctl)
6030                 return;
6031
6032         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6033                    (cache->free_space_ctl->free_space >= num_bytes));
6034
6035         put_caching_control(caching_ctl);
6036 }
6037
6038 static noinline int
6039 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6040 {
6041         struct btrfs_caching_control *caching_ctl;
6042         int ret = 0;
6043
6044         caching_ctl = get_caching_control(cache);
6045         if (!caching_ctl)
6046                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6047
6048         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6049         if (cache->cached == BTRFS_CACHE_ERROR)
6050                 ret = -EIO;
6051         put_caching_control(caching_ctl);
6052         return ret;
6053 }
6054
6055 int __get_raid_index(u64 flags)
6056 {
6057         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6058                 return BTRFS_RAID_RAID10;
6059         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6060                 return BTRFS_RAID_RAID1;
6061         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6062                 return BTRFS_RAID_DUP;
6063         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6064                 return BTRFS_RAID_RAID0;
6065         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6066                 return BTRFS_RAID_RAID5;
6067         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6068                 return BTRFS_RAID_RAID6;
6069
6070         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6071 }
6072
6073 int get_block_group_index(struct btrfs_block_group_cache *cache)
6074 {
6075         return __get_raid_index(cache->flags);
6076 }
6077
6078 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6079         [BTRFS_RAID_RAID10]     = "raid10",
6080         [BTRFS_RAID_RAID1]      = "raid1",
6081         [BTRFS_RAID_DUP]        = "dup",
6082         [BTRFS_RAID_RAID0]      = "raid0",
6083         [BTRFS_RAID_SINGLE]     = "single",
6084         [BTRFS_RAID_RAID5]      = "raid5",
6085         [BTRFS_RAID_RAID6]      = "raid6",
6086 };
6087
6088 static const char *get_raid_name(enum btrfs_raid_types type)
6089 {
6090         if (type >= BTRFS_NR_RAID_TYPES)
6091                 return NULL;
6092
6093         return btrfs_raid_type_names[type];
6094 }
6095
6096 enum btrfs_loop_type {
6097         LOOP_CACHING_NOWAIT = 0,
6098         LOOP_CACHING_WAIT = 1,
6099         LOOP_ALLOC_CHUNK = 2,
6100         LOOP_NO_EMPTY_SIZE = 3,
6101 };
6102
6103 /*
6104  * walks the btree of allocated extents and find a hole of a given size.
6105  * The key ins is changed to record the hole:
6106  * ins->objectid == start position
6107  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6108  * ins->offset == the size of the hole.
6109  * Any available blocks before search_start are skipped.
6110  *
6111  * If there is no suitable free space, we will record the max size of
6112  * the free space extent currently.
6113  */
6114 static noinline int find_free_extent(struct btrfs_root *orig_root,
6115                                      u64 num_bytes, u64 empty_size,
6116                                      u64 hint_byte, struct btrfs_key *ins,
6117                                      u64 flags)
6118 {
6119         int ret = 0;
6120         struct btrfs_root *root = orig_root->fs_info->extent_root;
6121         struct btrfs_free_cluster *last_ptr = NULL;
6122         struct btrfs_block_group_cache *block_group = NULL;
6123         struct btrfs_block_group_cache *used_block_group;
6124         u64 search_start = 0;
6125         u64 max_extent_size = 0;
6126         int empty_cluster = 2 * 1024 * 1024;
6127         struct btrfs_space_info *space_info;
6128         int loop = 0;
6129         int index = __get_raid_index(flags);
6130         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6131                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6132         bool failed_cluster_refill = false;
6133         bool failed_alloc = false;
6134         bool use_cluster = true;
6135         bool have_caching_bg = false;
6136
6137         WARN_ON(num_bytes < root->sectorsize);
6138         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
6139         ins->objectid = 0;
6140         ins->offset = 0;
6141
6142         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6143
6144         space_info = __find_space_info(root->fs_info, flags);
6145         if (!space_info) {
6146                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6147                 return -ENOSPC;
6148         }
6149
6150         /*
6151          * If the space info is for both data and metadata it means we have a
6152          * small filesystem and we can't use the clustering stuff.
6153          */
6154         if (btrfs_mixed_space_info(space_info))
6155                 use_cluster = false;
6156
6157         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6158                 last_ptr = &root->fs_info->meta_alloc_cluster;
6159                 if (!btrfs_test_opt(root, SSD))
6160                         empty_cluster = 64 * 1024;
6161         }
6162
6163         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6164             btrfs_test_opt(root, SSD)) {
6165                 last_ptr = &root->fs_info->data_alloc_cluster;
6166         }
6167
6168         if (last_ptr) {
6169                 spin_lock(&last_ptr->lock);
6170                 if (last_ptr->block_group)
6171                         hint_byte = last_ptr->window_start;
6172                 spin_unlock(&last_ptr->lock);
6173         }
6174
6175         search_start = max(search_start, first_logical_byte(root, 0));
6176         search_start = max(search_start, hint_byte);
6177
6178         if (!last_ptr)
6179                 empty_cluster = 0;
6180
6181         if (search_start == hint_byte) {
6182                 block_group = btrfs_lookup_block_group(root->fs_info,
6183                                                        search_start);
6184                 used_block_group = block_group;
6185                 /*
6186                  * we don't want to use the block group if it doesn't match our
6187                  * allocation bits, or if its not cached.
6188                  *
6189                  * However if we are re-searching with an ideal block group
6190                  * picked out then we don't care that the block group is cached.
6191                  */
6192                 if (block_group && block_group_bits(block_group, flags) &&
6193                     block_group->cached != BTRFS_CACHE_NO) {
6194                         down_read(&space_info->groups_sem);
6195                         if (list_empty(&block_group->list) ||
6196                             block_group->ro) {
6197                                 /*
6198                                  * someone is removing this block group,
6199                                  * we can't jump into the have_block_group
6200                                  * target because our list pointers are not
6201                                  * valid
6202                                  */
6203                                 btrfs_put_block_group(block_group);
6204                                 up_read(&space_info->groups_sem);
6205                         } else {
6206                                 index = get_block_group_index(block_group);
6207                                 goto have_block_group;
6208                         }
6209                 } else if (block_group) {
6210                         btrfs_put_block_group(block_group);
6211                 }
6212         }
6213 search:
6214         have_caching_bg = false;
6215         down_read(&space_info->groups_sem);
6216         list_for_each_entry(block_group, &space_info->block_groups[index],
6217                             list) {
6218                 u64 offset;
6219                 int cached;
6220
6221                 used_block_group = block_group;
6222                 btrfs_get_block_group(block_group);
6223                 search_start = block_group->key.objectid;
6224
6225                 /*
6226                  * this can happen if we end up cycling through all the
6227                  * raid types, but we want to make sure we only allocate
6228                  * for the proper type.
6229                  */
6230                 if (!block_group_bits(block_group, flags)) {
6231                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6232                                 BTRFS_BLOCK_GROUP_RAID1 |
6233                                 BTRFS_BLOCK_GROUP_RAID5 |
6234                                 BTRFS_BLOCK_GROUP_RAID6 |
6235                                 BTRFS_BLOCK_GROUP_RAID10;
6236
6237                         /*
6238                          * if they asked for extra copies and this block group
6239                          * doesn't provide them, bail.  This does allow us to
6240                          * fill raid0 from raid1.
6241                          */
6242                         if ((flags & extra) && !(block_group->flags & extra))
6243                                 goto loop;
6244                 }
6245
6246 have_block_group:
6247                 cached = block_group_cache_done(block_group);
6248                 if (unlikely(!cached)) {
6249                         ret = cache_block_group(block_group, 0);
6250                         BUG_ON(ret < 0);
6251                         ret = 0;
6252                 }
6253
6254                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6255                         goto loop;
6256                 if (unlikely(block_group->ro))
6257                         goto loop;
6258
6259                 /*
6260                  * Ok we want to try and use the cluster allocator, so
6261                  * lets look there
6262                  */
6263                 if (last_ptr) {
6264                         unsigned long aligned_cluster;
6265                         /*
6266                          * the refill lock keeps out other
6267                          * people trying to start a new cluster
6268                          */
6269                         spin_lock(&last_ptr->refill_lock);
6270                         used_block_group = last_ptr->block_group;
6271                         if (used_block_group != block_group &&
6272                             (!used_block_group ||
6273                              used_block_group->ro ||
6274                              !block_group_bits(used_block_group, flags))) {
6275                                 used_block_group = block_group;
6276                                 goto refill_cluster;
6277                         }
6278
6279                         if (used_block_group != block_group)
6280                                 btrfs_get_block_group(used_block_group);
6281
6282                         offset = btrfs_alloc_from_cluster(used_block_group,
6283                                                 last_ptr,
6284                                                 num_bytes,
6285                                                 used_block_group->key.objectid,
6286                                                 &max_extent_size);
6287                         if (offset) {
6288                                 /* we have a block, we're done */
6289                                 spin_unlock(&last_ptr->refill_lock);
6290                                 trace_btrfs_reserve_extent_cluster(root,
6291                                         block_group, search_start, num_bytes);
6292                                 goto checks;
6293                         }
6294
6295                         WARN_ON(last_ptr->block_group != used_block_group);
6296                         if (used_block_group != block_group) {
6297                                 btrfs_put_block_group(used_block_group);
6298                                 used_block_group = block_group;
6299                         }
6300 refill_cluster:
6301                         BUG_ON(used_block_group != block_group);
6302                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6303                          * set up a new clusters, so lets just skip it
6304                          * and let the allocator find whatever block
6305                          * it can find.  If we reach this point, we
6306                          * will have tried the cluster allocator
6307                          * plenty of times and not have found
6308                          * anything, so we are likely way too
6309                          * fragmented for the clustering stuff to find
6310                          * anything.
6311                          *
6312                          * However, if the cluster is taken from the
6313                          * current block group, release the cluster
6314                          * first, so that we stand a better chance of
6315                          * succeeding in the unclustered
6316                          * allocation.  */
6317                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6318                             last_ptr->block_group != block_group) {
6319                                 spin_unlock(&last_ptr->refill_lock);
6320                                 goto unclustered_alloc;
6321                         }
6322
6323                         /*
6324                          * this cluster didn't work out, free it and
6325                          * start over
6326                          */
6327                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6328
6329                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6330                                 spin_unlock(&last_ptr->refill_lock);
6331                                 goto unclustered_alloc;
6332                         }
6333
6334                         aligned_cluster = max_t(unsigned long,
6335                                                 empty_cluster + empty_size,
6336                                               block_group->full_stripe_len);
6337
6338                         /* allocate a cluster in this block group */
6339                         ret = btrfs_find_space_cluster(root, block_group,
6340                                                        last_ptr, search_start,
6341                                                        num_bytes,
6342                                                        aligned_cluster);
6343                         if (ret == 0) {
6344                                 /*
6345                                  * now pull our allocation out of this
6346                                  * cluster
6347                                  */
6348                                 offset = btrfs_alloc_from_cluster(block_group,
6349                                                         last_ptr,
6350                                                         num_bytes,
6351                                                         search_start,
6352                                                         &max_extent_size);
6353                                 if (offset) {
6354                                         /* we found one, proceed */
6355                                         spin_unlock(&last_ptr->refill_lock);
6356                                         trace_btrfs_reserve_extent_cluster(root,
6357                                                 block_group, search_start,
6358                                                 num_bytes);
6359                                         goto checks;
6360                                 }
6361                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6362                                    && !failed_cluster_refill) {
6363                                 spin_unlock(&last_ptr->refill_lock);
6364
6365                                 failed_cluster_refill = true;
6366                                 wait_block_group_cache_progress(block_group,
6367                                        num_bytes + empty_cluster + empty_size);
6368                                 goto have_block_group;
6369                         }
6370
6371                         /*
6372                          * at this point we either didn't find a cluster
6373                          * or we weren't able to allocate a block from our
6374                          * cluster.  Free the cluster we've been trying
6375                          * to use, and go to the next block group
6376                          */
6377                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6378                         spin_unlock(&last_ptr->refill_lock);
6379                         goto loop;
6380                 }
6381
6382 unclustered_alloc:
6383                 spin_lock(&block_group->free_space_ctl->tree_lock);
6384                 if (cached &&
6385                     block_group->free_space_ctl->free_space <
6386                     num_bytes + empty_cluster + empty_size) {
6387                         if (block_group->free_space_ctl->free_space >
6388                             max_extent_size)
6389                                 max_extent_size =
6390                                         block_group->free_space_ctl->free_space;
6391                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6392                         goto loop;
6393                 }
6394                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6395
6396                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6397                                                     num_bytes, empty_size,
6398                                                     &max_extent_size);
6399                 /*
6400                  * If we didn't find a chunk, and we haven't failed on this
6401                  * block group before, and this block group is in the middle of
6402                  * caching and we are ok with waiting, then go ahead and wait
6403                  * for progress to be made, and set failed_alloc to true.
6404                  *
6405                  * If failed_alloc is true then we've already waited on this
6406                  * block group once and should move on to the next block group.
6407                  */
6408                 if (!offset && !failed_alloc && !cached &&
6409                     loop > LOOP_CACHING_NOWAIT) {
6410                         wait_block_group_cache_progress(block_group,
6411                                                 num_bytes + empty_size);
6412                         failed_alloc = true;
6413                         goto have_block_group;
6414                 } else if (!offset) {
6415                         if (!cached)
6416                                 have_caching_bg = true;
6417                         goto loop;
6418                 }
6419 checks:
6420                 search_start = stripe_align(root, used_block_group,
6421                                             offset, num_bytes);
6422
6423                 /* move on to the next group */
6424                 if (search_start + num_bytes >
6425                     used_block_group->key.objectid + used_block_group->key.offset) {
6426                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6427                         goto loop;
6428                 }
6429
6430                 if (offset < search_start)
6431                         btrfs_add_free_space(used_block_group, offset,
6432                                              search_start - offset);
6433                 BUG_ON(offset > search_start);
6434
6435                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
6436                                                   alloc_type);
6437                 if (ret == -EAGAIN) {
6438                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6439                         goto loop;
6440                 }
6441
6442                 /* we are all good, lets return */
6443                 ins->objectid = search_start;
6444                 ins->offset = num_bytes;
6445
6446                 trace_btrfs_reserve_extent(orig_root, block_group,
6447                                            search_start, num_bytes);
6448                 if (used_block_group != block_group)
6449                         btrfs_put_block_group(used_block_group);
6450                 btrfs_put_block_group(block_group);
6451                 break;
6452 loop:
6453                 failed_cluster_refill = false;
6454                 failed_alloc = false;
6455                 BUG_ON(index != get_block_group_index(block_group));
6456                 if (used_block_group != block_group)
6457                         btrfs_put_block_group(used_block_group);
6458                 btrfs_put_block_group(block_group);
6459         }
6460         up_read(&space_info->groups_sem);
6461
6462         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6463                 goto search;
6464
6465         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6466                 goto search;
6467
6468         /*
6469          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6470          *                      caching kthreads as we move along
6471          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6472          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6473          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6474          *                      again
6475          */
6476         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6477                 index = 0;
6478                 loop++;
6479                 if (loop == LOOP_ALLOC_CHUNK) {
6480                         struct btrfs_trans_handle *trans;
6481
6482                         trans = btrfs_join_transaction(root);
6483                         if (IS_ERR(trans)) {
6484                                 ret = PTR_ERR(trans);
6485                                 goto out;
6486                         }
6487
6488                         ret = do_chunk_alloc(trans, root, flags,
6489                                              CHUNK_ALLOC_FORCE);
6490                         /*
6491                          * Do not bail out on ENOSPC since we
6492                          * can do more things.
6493                          */
6494                         if (ret < 0 && ret != -ENOSPC)
6495                                 btrfs_abort_transaction(trans,
6496                                                         root, ret);
6497                         else
6498                                 ret = 0;
6499                         btrfs_end_transaction(trans, root);
6500                         if (ret)
6501                                 goto out;
6502                 }
6503
6504                 if (loop == LOOP_NO_EMPTY_SIZE) {
6505                         empty_size = 0;
6506                         empty_cluster = 0;
6507                 }
6508
6509                 goto search;
6510         } else if (!ins->objectid) {
6511                 ret = -ENOSPC;
6512         } else if (ins->objectid) {
6513                 ret = 0;
6514         }
6515 out:
6516         if (ret == -ENOSPC)
6517                 ins->offset = max_extent_size;
6518         return ret;
6519 }
6520
6521 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6522                             int dump_block_groups)
6523 {
6524         struct btrfs_block_group_cache *cache;
6525         int index = 0;
6526
6527         spin_lock(&info->lock);
6528         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
6529                info->flags,
6530                info->total_bytes - info->bytes_used - info->bytes_pinned -
6531                info->bytes_reserved - info->bytes_readonly,
6532                (info->full) ? "" : "not ");
6533         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
6534                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6535                info->total_bytes, info->bytes_used, info->bytes_pinned,
6536                info->bytes_reserved, info->bytes_may_use,
6537                info->bytes_readonly);
6538         spin_unlock(&info->lock);
6539
6540         if (!dump_block_groups)
6541                 return;
6542
6543         down_read(&info->groups_sem);
6544 again:
6545         list_for_each_entry(cache, &info->block_groups[index], list) {
6546                 spin_lock(&cache->lock);
6547                 printk(KERN_INFO "BTRFS: "
6548                            "block group %llu has %llu bytes, "
6549                            "%llu used %llu pinned %llu reserved %s\n",
6550                        cache->key.objectid, cache->key.offset,
6551                        btrfs_block_group_used(&cache->item), cache->pinned,
6552                        cache->reserved, cache->ro ? "[readonly]" : "");
6553                 btrfs_dump_free_space(cache, bytes);
6554                 spin_unlock(&cache->lock);
6555         }
6556         if (++index < BTRFS_NR_RAID_TYPES)
6557                 goto again;
6558         up_read(&info->groups_sem);
6559 }
6560
6561 int btrfs_reserve_extent(struct btrfs_root *root,
6562                          u64 num_bytes, u64 min_alloc_size,
6563                          u64 empty_size, u64 hint_byte,
6564                          struct btrfs_key *ins, int is_data)
6565 {
6566         bool final_tried = false;
6567         u64 flags;
6568         int ret;
6569
6570         flags = btrfs_get_alloc_profile(root, is_data);
6571 again:
6572         WARN_ON(num_bytes < root->sectorsize);
6573         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
6574                                flags);
6575
6576         if (ret == -ENOSPC) {
6577                 if (!final_tried && ins->offset) {
6578                         num_bytes = min(num_bytes >> 1, ins->offset);
6579                         num_bytes = round_down(num_bytes, root->sectorsize);
6580                         num_bytes = max(num_bytes, min_alloc_size);
6581                         if (num_bytes == min_alloc_size)
6582                                 final_tried = true;
6583                         goto again;
6584                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6585                         struct btrfs_space_info *sinfo;
6586
6587                         sinfo = __find_space_info(root->fs_info, flags);
6588                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6589                                 flags, num_bytes);
6590                         if (sinfo)
6591                                 dump_space_info(sinfo, num_bytes, 1);
6592                 }
6593         }
6594
6595         return ret;
6596 }
6597
6598 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6599                                         u64 start, u64 len, int pin)
6600 {
6601         struct btrfs_block_group_cache *cache;
6602         int ret = 0;
6603
6604         cache = btrfs_lookup_block_group(root->fs_info, start);
6605         if (!cache) {
6606                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6607                         start);
6608                 return -ENOSPC;
6609         }
6610
6611         if (btrfs_test_opt(root, DISCARD))
6612                 ret = btrfs_discard_extent(root, start, len, NULL);
6613
6614         if (pin)
6615                 pin_down_extent(root, cache, start, len, 1);
6616         else {
6617                 btrfs_add_free_space(cache, start, len);
6618                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6619         }
6620         btrfs_put_block_group(cache);
6621
6622         trace_btrfs_reserved_extent_free(root, start, len);
6623
6624         return ret;
6625 }
6626
6627 int btrfs_free_reserved_extent(struct btrfs_root *root,
6628                                         u64 start, u64 len)
6629 {
6630         return __btrfs_free_reserved_extent(root, start, len, 0);
6631 }
6632
6633 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6634                                        u64 start, u64 len)
6635 {
6636         return __btrfs_free_reserved_extent(root, start, len, 1);
6637 }
6638
6639 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6640                                       struct btrfs_root *root,
6641                                       u64 parent, u64 root_objectid,
6642                                       u64 flags, u64 owner, u64 offset,
6643                                       struct btrfs_key *ins, int ref_mod)
6644 {
6645         int ret;
6646         struct btrfs_fs_info *fs_info = root->fs_info;
6647         struct btrfs_extent_item *extent_item;
6648         struct btrfs_extent_inline_ref *iref;
6649         struct btrfs_path *path;
6650         struct extent_buffer *leaf;
6651         int type;
6652         u32 size;
6653
6654         if (parent > 0)
6655                 type = BTRFS_SHARED_DATA_REF_KEY;
6656         else
6657                 type = BTRFS_EXTENT_DATA_REF_KEY;
6658
6659         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6660
6661         path = btrfs_alloc_path();
6662         if (!path)
6663                 return -ENOMEM;
6664
6665         path->leave_spinning = 1;
6666         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6667                                       ins, size);
6668         if (ret) {
6669                 btrfs_free_path(path);
6670                 return ret;
6671         }
6672
6673         leaf = path->nodes[0];
6674         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6675                                      struct btrfs_extent_item);
6676         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6677         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6678         btrfs_set_extent_flags(leaf, extent_item,
6679                                flags | BTRFS_EXTENT_FLAG_DATA);
6680
6681         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6682         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6683         if (parent > 0) {
6684                 struct btrfs_shared_data_ref *ref;
6685                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6686                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6687                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6688         } else {
6689                 struct btrfs_extent_data_ref *ref;
6690                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6691                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6692                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6693                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6694                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6695         }
6696
6697         btrfs_mark_buffer_dirty(path->nodes[0]);
6698         btrfs_free_path(path);
6699
6700         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6701         if (ret) { /* -ENOENT, logic error */
6702                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6703                         ins->objectid, ins->offset);
6704                 BUG();
6705         }
6706         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
6707         return ret;
6708 }
6709
6710 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6711                                      struct btrfs_root *root,
6712                                      u64 parent, u64 root_objectid,
6713                                      u64 flags, struct btrfs_disk_key *key,
6714                                      int level, struct btrfs_key *ins)
6715 {
6716         int ret;
6717         struct btrfs_fs_info *fs_info = root->fs_info;
6718         struct btrfs_extent_item *extent_item;
6719         struct btrfs_tree_block_info *block_info;
6720         struct btrfs_extent_inline_ref *iref;
6721         struct btrfs_path *path;
6722         struct extent_buffer *leaf;
6723         u32 size = sizeof(*extent_item) + sizeof(*iref);
6724         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6725                                                  SKINNY_METADATA);
6726
6727         if (!skinny_metadata)
6728                 size += sizeof(*block_info);
6729
6730         path = btrfs_alloc_path();
6731         if (!path) {
6732                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
6733                                                    root->leafsize);
6734                 return -ENOMEM;
6735         }
6736
6737         path->leave_spinning = 1;
6738         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6739                                       ins, size);
6740         if (ret) {
6741                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
6742                                                    root->leafsize);
6743                 btrfs_free_path(path);
6744                 return ret;
6745         }
6746
6747         leaf = path->nodes[0];
6748         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6749                                      struct btrfs_extent_item);
6750         btrfs_set_extent_refs(leaf, extent_item, 1);
6751         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6752         btrfs_set_extent_flags(leaf, extent_item,
6753                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6754
6755         if (skinny_metadata) {
6756                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6757         } else {
6758                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6759                 btrfs_set_tree_block_key(leaf, block_info, key);
6760                 btrfs_set_tree_block_level(leaf, block_info, level);
6761                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6762         }
6763
6764         if (parent > 0) {
6765                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6766                 btrfs_set_extent_inline_ref_type(leaf, iref,
6767                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6768                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6769         } else {
6770                 btrfs_set_extent_inline_ref_type(leaf, iref,
6771                                                  BTRFS_TREE_BLOCK_REF_KEY);
6772                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6773         }
6774
6775         btrfs_mark_buffer_dirty(leaf);
6776         btrfs_free_path(path);
6777
6778         ret = update_block_group(root, ins->objectid, root->leafsize, 1);
6779         if (ret) { /* -ENOENT, logic error */
6780                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6781                         ins->objectid, ins->offset);
6782                 BUG();
6783         }
6784
6785         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->leafsize);
6786         return ret;
6787 }
6788
6789 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6790                                      struct btrfs_root *root,
6791                                      u64 root_objectid, u64 owner,
6792                                      u64 offset, struct btrfs_key *ins)
6793 {
6794         int ret;
6795
6796         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6797
6798         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6799                                          ins->offset, 0,
6800                                          root_objectid, owner, offset,
6801                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6802         return ret;
6803 }
6804
6805 /*
6806  * this is used by the tree logging recovery code.  It records that
6807  * an extent has been allocated and makes sure to clear the free
6808  * space cache bits as well
6809  */
6810 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6811                                    struct btrfs_root *root,
6812                                    u64 root_objectid, u64 owner, u64 offset,
6813                                    struct btrfs_key *ins)
6814 {
6815         int ret;
6816         struct btrfs_block_group_cache *block_group;
6817
6818         /*
6819          * Mixed block groups will exclude before processing the log so we only
6820          * need to do the exlude dance if this fs isn't mixed.
6821          */
6822         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
6823                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
6824                 if (ret)
6825                         return ret;
6826         }
6827
6828         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6829         if (!block_group)
6830                 return -EINVAL;
6831
6832         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6833                                           RESERVE_ALLOC_NO_ACCOUNT);
6834         BUG_ON(ret); /* logic error */
6835         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6836                                          0, owner, offset, ins, 1);
6837         btrfs_put_block_group(block_group);
6838         return ret;
6839 }
6840
6841 static struct extent_buffer *
6842 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6843                       u64 bytenr, u32 blocksize, int level)
6844 {
6845         struct extent_buffer *buf;
6846
6847         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6848         if (!buf)
6849                 return ERR_PTR(-ENOMEM);
6850         btrfs_set_header_generation(buf, trans->transid);
6851         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6852         btrfs_tree_lock(buf);
6853         clean_tree_block(trans, root, buf);
6854         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6855
6856         btrfs_set_lock_blocking(buf);
6857         btrfs_set_buffer_uptodate(buf);
6858
6859         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6860                 /*
6861                  * we allow two log transactions at a time, use different
6862                  * EXENT bit to differentiate dirty pages.
6863                  */
6864                 if (root->log_transid % 2 == 0)
6865                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6866                                         buf->start + buf->len - 1, GFP_NOFS);
6867                 else
6868                         set_extent_new(&root->dirty_log_pages, buf->start,
6869                                         buf->start + buf->len - 1, GFP_NOFS);
6870         } else {
6871                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6872                          buf->start + buf->len - 1, GFP_NOFS);
6873         }
6874         trans->blocks_used++;
6875         /* this returns a buffer locked for blocking */
6876         return buf;
6877 }
6878
6879 static struct btrfs_block_rsv *
6880 use_block_rsv(struct btrfs_trans_handle *trans,
6881               struct btrfs_root *root, u32 blocksize)
6882 {
6883         struct btrfs_block_rsv *block_rsv;
6884         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6885         int ret;
6886         bool global_updated = false;
6887
6888         block_rsv = get_block_rsv(trans, root);
6889
6890         if (unlikely(block_rsv->size == 0))
6891                 goto try_reserve;
6892 again:
6893         ret = block_rsv_use_bytes(block_rsv, blocksize);
6894         if (!ret)
6895                 return block_rsv;
6896
6897         if (block_rsv->failfast)
6898                 return ERR_PTR(ret);
6899
6900         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
6901                 global_updated = true;
6902                 update_global_block_rsv(root->fs_info);
6903                 goto again;
6904         }
6905
6906         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6907                 static DEFINE_RATELIMIT_STATE(_rs,
6908                                 DEFAULT_RATELIMIT_INTERVAL * 10,
6909                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
6910                 if (__ratelimit(&_rs))
6911                         WARN(1, KERN_DEBUG
6912                                 "BTRFS: block rsv returned %d\n", ret);
6913         }
6914 try_reserve:
6915         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
6916                                      BTRFS_RESERVE_NO_FLUSH);
6917         if (!ret)
6918                 return block_rsv;
6919         /*
6920          * If we couldn't reserve metadata bytes try and use some from
6921          * the global reserve if its space type is the same as the global
6922          * reservation.
6923          */
6924         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
6925             block_rsv->space_info == global_rsv->space_info) {
6926                 ret = block_rsv_use_bytes(global_rsv, blocksize);
6927                 if (!ret)
6928                         return global_rsv;
6929         }
6930         return ERR_PTR(ret);
6931 }
6932
6933 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6934                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6935 {
6936         block_rsv_add_bytes(block_rsv, blocksize, 0);
6937         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6938 }
6939
6940 /*
6941  * finds a free extent and does all the dirty work required for allocation
6942  * returns the key for the extent through ins, and a tree buffer for
6943  * the first block of the extent through buf.
6944  *
6945  * returns the tree buffer or NULL.
6946  */
6947 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6948                                         struct btrfs_root *root, u32 blocksize,
6949                                         u64 parent, u64 root_objectid,
6950                                         struct btrfs_disk_key *key, int level,
6951                                         u64 hint, u64 empty_size)
6952 {
6953         struct btrfs_key ins;
6954         struct btrfs_block_rsv *block_rsv;
6955         struct extent_buffer *buf;
6956         u64 flags = 0;
6957         int ret;
6958         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6959                                                  SKINNY_METADATA);
6960
6961         block_rsv = use_block_rsv(trans, root, blocksize);
6962         if (IS_ERR(block_rsv))
6963                 return ERR_CAST(block_rsv);
6964
6965         ret = btrfs_reserve_extent(root, blocksize, blocksize,
6966                                    empty_size, hint, &ins, 0);
6967         if (ret) {
6968                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6969                 return ERR_PTR(ret);
6970         }
6971
6972         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6973                                     blocksize, level);
6974         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6975
6976         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6977                 if (parent == 0)
6978                         parent = ins.objectid;
6979                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6980         } else
6981                 BUG_ON(parent > 0);
6982
6983         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6984                 struct btrfs_delayed_extent_op *extent_op;
6985                 extent_op = btrfs_alloc_delayed_extent_op();
6986                 BUG_ON(!extent_op); /* -ENOMEM */
6987                 if (key)
6988                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6989                 else
6990                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6991                 extent_op->flags_to_set = flags;
6992                 if (skinny_metadata)
6993                         extent_op->update_key = 0;
6994                 else
6995                         extent_op->update_key = 1;
6996                 extent_op->update_flags = 1;
6997                 extent_op->is_data = 0;
6998                 extent_op->level = level;
6999
7000                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7001                                         ins.objectid,
7002                                         ins.offset, parent, root_objectid,
7003                                         level, BTRFS_ADD_DELAYED_EXTENT,
7004                                         extent_op, 0);
7005                 BUG_ON(ret); /* -ENOMEM */
7006         }
7007         return buf;
7008 }
7009
7010 struct walk_control {
7011         u64 refs[BTRFS_MAX_LEVEL];
7012         u64 flags[BTRFS_MAX_LEVEL];
7013         struct btrfs_key update_progress;
7014         int stage;
7015         int level;
7016         int shared_level;
7017         int update_ref;
7018         int keep_locks;
7019         int reada_slot;
7020         int reada_count;
7021         int for_reloc;
7022 };
7023
7024 #define DROP_REFERENCE  1
7025 #define UPDATE_BACKREF  2
7026
7027 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7028                                      struct btrfs_root *root,
7029                                      struct walk_control *wc,
7030                                      struct btrfs_path *path)
7031 {
7032         u64 bytenr;
7033         u64 generation;
7034         u64 refs;
7035         u64 flags;
7036         u32 nritems;
7037         u32 blocksize;
7038         struct btrfs_key key;
7039         struct extent_buffer *eb;
7040         int ret;
7041         int slot;
7042         int nread = 0;
7043
7044         if (path->slots[wc->level] < wc->reada_slot) {
7045                 wc->reada_count = wc->reada_count * 2 / 3;
7046                 wc->reada_count = max(wc->reada_count, 2);
7047         } else {
7048                 wc->reada_count = wc->reada_count * 3 / 2;
7049                 wc->reada_count = min_t(int, wc->reada_count,
7050                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7051         }
7052
7053         eb = path->nodes[wc->level];
7054         nritems = btrfs_header_nritems(eb);
7055         blocksize = btrfs_level_size(root, wc->level - 1);
7056
7057         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7058                 if (nread >= wc->reada_count)
7059                         break;
7060
7061                 cond_resched();
7062                 bytenr = btrfs_node_blockptr(eb, slot);
7063                 generation = btrfs_node_ptr_generation(eb, slot);
7064
7065                 if (slot == path->slots[wc->level])
7066                         goto reada;
7067
7068                 if (wc->stage == UPDATE_BACKREF &&
7069                     generation <= root->root_key.offset)
7070                         continue;
7071
7072                 /* We don't lock the tree block, it's OK to be racy here */
7073                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7074                                                wc->level - 1, 1, &refs,
7075                                                &flags);
7076                 /* We don't care about errors in readahead. */
7077                 if (ret < 0)
7078                         continue;
7079                 BUG_ON(refs == 0);
7080
7081                 if (wc->stage == DROP_REFERENCE) {
7082                         if (refs == 1)
7083                                 goto reada;
7084
7085                         if (wc->level == 1 &&
7086                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7087                                 continue;
7088                         if (!wc->update_ref ||
7089                             generation <= root->root_key.offset)
7090                                 continue;
7091                         btrfs_node_key_to_cpu(eb, &key, slot);
7092                         ret = btrfs_comp_cpu_keys(&key,
7093                                                   &wc->update_progress);
7094                         if (ret < 0)
7095                                 continue;
7096                 } else {
7097                         if (wc->level == 1 &&
7098                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7099                                 continue;
7100                 }
7101 reada:
7102                 ret = readahead_tree_block(root, bytenr, blocksize,
7103                                            generation);
7104                 if (ret)
7105                         break;
7106                 nread++;
7107         }
7108         wc->reada_slot = slot;
7109 }
7110
7111 /*
7112  * helper to process tree block while walking down the tree.
7113  *
7114  * when wc->stage == UPDATE_BACKREF, this function updates
7115  * back refs for pointers in the block.
7116  *
7117  * NOTE: return value 1 means we should stop walking down.
7118  */
7119 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7120                                    struct btrfs_root *root,
7121                                    struct btrfs_path *path,
7122                                    struct walk_control *wc, int lookup_info)
7123 {
7124         int level = wc->level;
7125         struct extent_buffer *eb = path->nodes[level];
7126         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7127         int ret;
7128
7129         if (wc->stage == UPDATE_BACKREF &&
7130             btrfs_header_owner(eb) != root->root_key.objectid)
7131                 return 1;
7132
7133         /*
7134          * when reference count of tree block is 1, it won't increase
7135          * again. once full backref flag is set, we never clear it.
7136          */
7137         if (lookup_info &&
7138             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7139              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7140                 BUG_ON(!path->locks[level]);
7141                 ret = btrfs_lookup_extent_info(trans, root,
7142                                                eb->start, level, 1,
7143                                                &wc->refs[level],
7144                                                &wc->flags[level]);
7145                 BUG_ON(ret == -ENOMEM);
7146                 if (ret)
7147                         return ret;
7148                 BUG_ON(wc->refs[level] == 0);
7149         }
7150
7151         if (wc->stage == DROP_REFERENCE) {
7152                 if (wc->refs[level] > 1)
7153                         return 1;
7154
7155                 if (path->locks[level] && !wc->keep_locks) {
7156                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7157                         path->locks[level] = 0;
7158                 }
7159                 return 0;
7160         }
7161
7162         /* wc->stage == UPDATE_BACKREF */
7163         if (!(wc->flags[level] & flag)) {
7164                 BUG_ON(!path->locks[level]);
7165                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
7166                 BUG_ON(ret); /* -ENOMEM */
7167                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
7168                 BUG_ON(ret); /* -ENOMEM */
7169                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7170                                                   eb->len, flag,
7171                                                   btrfs_header_level(eb), 0);
7172                 BUG_ON(ret); /* -ENOMEM */
7173                 wc->flags[level] |= flag;
7174         }
7175
7176         /*
7177          * the block is shared by multiple trees, so it's not good to
7178          * keep the tree lock
7179          */
7180         if (path->locks[level] && level > 0) {
7181                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7182                 path->locks[level] = 0;
7183         }
7184         return 0;
7185 }
7186
7187 /*
7188  * helper to process tree block pointer.
7189  *
7190  * when wc->stage == DROP_REFERENCE, this function checks
7191  * reference count of the block pointed to. if the block
7192  * is shared and we need update back refs for the subtree
7193  * rooted at the block, this function changes wc->stage to
7194  * UPDATE_BACKREF. if the block is shared and there is no
7195  * need to update back, this function drops the reference
7196  * to the block.
7197  *
7198  * NOTE: return value 1 means we should stop walking down.
7199  */
7200 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
7201                                  struct btrfs_root *root,
7202                                  struct btrfs_path *path,
7203                                  struct walk_control *wc, int *lookup_info)
7204 {
7205         u64 bytenr;
7206         u64 generation;
7207         u64 parent;
7208         u32 blocksize;
7209         struct btrfs_key key;
7210         struct extent_buffer *next;
7211         int level = wc->level;
7212         int reada = 0;
7213         int ret = 0;
7214
7215         generation = btrfs_node_ptr_generation(path->nodes[level],
7216                                                path->slots[level]);
7217         /*
7218          * if the lower level block was created before the snapshot
7219          * was created, we know there is no need to update back refs
7220          * for the subtree
7221          */
7222         if (wc->stage == UPDATE_BACKREF &&
7223             generation <= root->root_key.offset) {
7224                 *lookup_info = 1;
7225                 return 1;
7226         }
7227
7228         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7229         blocksize = btrfs_level_size(root, level - 1);
7230
7231         next = btrfs_find_tree_block(root, bytenr, blocksize);
7232         if (!next) {
7233                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
7234                 if (!next)
7235                         return -ENOMEM;
7236                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
7237                                                level - 1);
7238                 reada = 1;
7239         }
7240         btrfs_tree_lock(next);
7241         btrfs_set_lock_blocking(next);
7242
7243         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7244                                        &wc->refs[level - 1],
7245                                        &wc->flags[level - 1]);
7246         if (ret < 0) {
7247                 btrfs_tree_unlock(next);
7248                 return ret;
7249         }
7250
7251         if (unlikely(wc->refs[level - 1] == 0)) {
7252                 btrfs_err(root->fs_info, "Missing references.");
7253                 BUG();
7254         }
7255         *lookup_info = 0;
7256
7257         if (wc->stage == DROP_REFERENCE) {
7258                 if (wc->refs[level - 1] > 1) {
7259                         if (level == 1 &&
7260                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7261                                 goto skip;
7262
7263                         if (!wc->update_ref ||
7264                             generation <= root->root_key.offset)
7265                                 goto skip;
7266
7267                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7268                                               path->slots[level]);
7269                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7270                         if (ret < 0)
7271                                 goto skip;
7272
7273                         wc->stage = UPDATE_BACKREF;
7274                         wc->shared_level = level - 1;
7275                 }
7276         } else {
7277                 if (level == 1 &&
7278                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7279                         goto skip;
7280         }
7281
7282         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7283                 btrfs_tree_unlock(next);
7284                 free_extent_buffer(next);
7285                 next = NULL;
7286                 *lookup_info = 1;
7287         }
7288
7289         if (!next) {
7290                 if (reada && level == 1)
7291                         reada_walk_down(trans, root, wc, path);
7292                 next = read_tree_block(root, bytenr, blocksize, generation);
7293                 if (!next || !extent_buffer_uptodate(next)) {
7294                         free_extent_buffer(next);
7295                         return -EIO;
7296                 }
7297                 btrfs_tree_lock(next);
7298                 btrfs_set_lock_blocking(next);
7299         }
7300
7301         level--;
7302         BUG_ON(level != btrfs_header_level(next));
7303         path->nodes[level] = next;
7304         path->slots[level] = 0;
7305         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7306         wc->level = level;
7307         if (wc->level == 1)
7308                 wc->reada_slot = 0;
7309         return 0;
7310 skip:
7311         wc->refs[level - 1] = 0;
7312         wc->flags[level - 1] = 0;
7313         if (wc->stage == DROP_REFERENCE) {
7314                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7315                         parent = path->nodes[level]->start;
7316                 } else {
7317                         BUG_ON(root->root_key.objectid !=
7318                                btrfs_header_owner(path->nodes[level]));
7319                         parent = 0;
7320                 }
7321
7322                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7323                                 root->root_key.objectid, level - 1, 0, 0);
7324                 BUG_ON(ret); /* -ENOMEM */
7325         }
7326         btrfs_tree_unlock(next);
7327         free_extent_buffer(next);
7328         *lookup_info = 1;
7329         return 1;
7330 }
7331
7332 /*
7333  * helper to process tree block while walking up the tree.
7334  *
7335  * when wc->stage == DROP_REFERENCE, this function drops
7336  * reference count on the block.
7337  *
7338  * when wc->stage == UPDATE_BACKREF, this function changes
7339  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7340  * to UPDATE_BACKREF previously while processing the block.
7341  *
7342  * NOTE: return value 1 means we should stop walking up.
7343  */
7344 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7345                                  struct btrfs_root *root,
7346                                  struct btrfs_path *path,
7347                                  struct walk_control *wc)
7348 {
7349         int ret;
7350         int level = wc->level;
7351         struct extent_buffer *eb = path->nodes[level];
7352         u64 parent = 0;
7353
7354         if (wc->stage == UPDATE_BACKREF) {
7355                 BUG_ON(wc->shared_level < level);
7356                 if (level < wc->shared_level)
7357                         goto out;
7358
7359                 ret = find_next_key(path, level + 1, &wc->update_progress);
7360                 if (ret > 0)
7361                         wc->update_ref = 0;
7362
7363                 wc->stage = DROP_REFERENCE;
7364                 wc->shared_level = -1;
7365                 path->slots[level] = 0;
7366
7367                 /*
7368                  * check reference count again if the block isn't locked.
7369                  * we should start walking down the tree again if reference
7370                  * count is one.
7371                  */
7372                 if (!path->locks[level]) {
7373                         BUG_ON(level == 0);
7374                         btrfs_tree_lock(eb);
7375                         btrfs_set_lock_blocking(eb);
7376                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7377
7378                         ret = btrfs_lookup_extent_info(trans, root,
7379                                                        eb->start, level, 1,
7380                                                        &wc->refs[level],
7381                                                        &wc->flags[level]);
7382                         if (ret < 0) {
7383                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7384                                 path->locks[level] = 0;
7385                                 return ret;
7386                         }
7387                         BUG_ON(wc->refs[level] == 0);
7388                         if (wc->refs[level] == 1) {
7389                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7390                                 path->locks[level] = 0;
7391                                 return 1;
7392                         }
7393                 }
7394         }
7395
7396         /* wc->stage == DROP_REFERENCE */
7397         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7398
7399         if (wc->refs[level] == 1) {
7400                 if (level == 0) {
7401                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7402                                 ret = btrfs_dec_ref(trans, root, eb, 1,
7403                                                     wc->for_reloc);
7404                         else
7405                                 ret = btrfs_dec_ref(trans, root, eb, 0,
7406                                                     wc->for_reloc);
7407                         BUG_ON(ret); /* -ENOMEM */
7408                 }
7409                 /* make block locked assertion in clean_tree_block happy */
7410                 if (!path->locks[level] &&
7411                     btrfs_header_generation(eb) == trans->transid) {
7412                         btrfs_tree_lock(eb);
7413                         btrfs_set_lock_blocking(eb);
7414                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7415                 }
7416                 clean_tree_block(trans, root, eb);
7417         }
7418
7419         if (eb == root->node) {
7420                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7421                         parent = eb->start;
7422                 else
7423                         BUG_ON(root->root_key.objectid !=
7424                                btrfs_header_owner(eb));
7425         } else {
7426                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7427                         parent = path->nodes[level + 1]->start;
7428                 else
7429                         BUG_ON(root->root_key.objectid !=
7430                                btrfs_header_owner(path->nodes[level + 1]));
7431         }
7432
7433         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7434 out:
7435         wc->refs[level] = 0;
7436         wc->flags[level] = 0;
7437         return 0;
7438 }
7439
7440 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7441                                    struct btrfs_root *root,
7442                                    struct btrfs_path *path,
7443                                    struct walk_control *wc)
7444 {
7445         int level = wc->level;
7446         int lookup_info = 1;
7447         int ret;
7448
7449         while (level >= 0) {
7450                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
7451                 if (ret > 0)
7452                         break;
7453
7454                 if (level == 0)
7455                         break;
7456
7457                 if (path->slots[level] >=
7458                     btrfs_header_nritems(path->nodes[level]))
7459                         break;
7460
7461                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
7462                 if (ret > 0) {
7463                         path->slots[level]++;
7464                         continue;
7465                 } else if (ret < 0)
7466                         return ret;
7467                 level = wc->level;
7468         }
7469         return 0;
7470 }
7471
7472 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
7473                                  struct btrfs_root *root,
7474                                  struct btrfs_path *path,
7475                                  struct walk_control *wc, int max_level)
7476 {
7477         int level = wc->level;
7478         int ret;
7479
7480         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
7481         while (level < max_level && path->nodes[level]) {
7482                 wc->level = level;
7483                 if (path->slots[level] + 1 <
7484                     btrfs_header_nritems(path->nodes[level])) {
7485                         path->slots[level]++;
7486                         return 0;
7487                 } else {
7488                         ret = walk_up_proc(trans, root, path, wc);
7489                         if (ret > 0)
7490                                 return 0;
7491
7492                         if (path->locks[level]) {
7493                                 btrfs_tree_unlock_rw(path->nodes[level],
7494                                                      path->locks[level]);
7495                                 path->locks[level] = 0;
7496                         }
7497                         free_extent_buffer(path->nodes[level]);
7498                         path->nodes[level] = NULL;
7499                         level++;
7500                 }
7501         }
7502         return 1;
7503 }
7504
7505 /*
7506  * drop a subvolume tree.
7507  *
7508  * this function traverses the tree freeing any blocks that only
7509  * referenced by the tree.
7510  *
7511  * when a shared tree block is found. this function decreases its
7512  * reference count by one. if update_ref is true, this function
7513  * also make sure backrefs for the shared block and all lower level
7514  * blocks are properly updated.
7515  *
7516  * If called with for_reloc == 0, may exit early with -EAGAIN
7517  */
7518 int btrfs_drop_snapshot(struct btrfs_root *root,
7519                          struct btrfs_block_rsv *block_rsv, int update_ref,
7520                          int for_reloc)
7521 {
7522         struct btrfs_path *path;
7523         struct btrfs_trans_handle *trans;
7524         struct btrfs_root *tree_root = root->fs_info->tree_root;
7525         struct btrfs_root_item *root_item = &root->root_item;
7526         struct walk_control *wc;
7527         struct btrfs_key key;
7528         int err = 0;
7529         int ret;
7530         int level;
7531         bool root_dropped = false;
7532
7533         path = btrfs_alloc_path();
7534         if (!path) {
7535                 err = -ENOMEM;
7536                 goto out;
7537         }
7538
7539         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7540         if (!wc) {
7541                 btrfs_free_path(path);
7542                 err = -ENOMEM;
7543                 goto out;
7544         }
7545
7546         trans = btrfs_start_transaction(tree_root, 0);
7547         if (IS_ERR(trans)) {
7548                 err = PTR_ERR(trans);
7549                 goto out_free;
7550         }
7551
7552         if (block_rsv)
7553                 trans->block_rsv = block_rsv;
7554
7555         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
7556                 level = btrfs_header_level(root->node);
7557                 path->nodes[level] = btrfs_lock_root_node(root);
7558                 btrfs_set_lock_blocking(path->nodes[level]);
7559                 path->slots[level] = 0;
7560                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7561                 memset(&wc->update_progress, 0,
7562                        sizeof(wc->update_progress));
7563         } else {
7564                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
7565                 memcpy(&wc->update_progress, &key,
7566                        sizeof(wc->update_progress));
7567
7568                 level = root_item->drop_level;
7569                 BUG_ON(level == 0);
7570                 path->lowest_level = level;
7571                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
7572                 path->lowest_level = 0;
7573                 if (ret < 0) {
7574                         err = ret;
7575                         goto out_end_trans;
7576                 }
7577                 WARN_ON(ret > 0);
7578
7579                 /*
7580                  * unlock our path, this is safe because only this
7581                  * function is allowed to delete this snapshot
7582                  */
7583                 btrfs_unlock_up_safe(path, 0);
7584
7585                 level = btrfs_header_level(root->node);
7586                 while (1) {
7587                         btrfs_tree_lock(path->nodes[level]);
7588                         btrfs_set_lock_blocking(path->nodes[level]);
7589                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7590
7591                         ret = btrfs_lookup_extent_info(trans, root,
7592                                                 path->nodes[level]->start,
7593                                                 level, 1, &wc->refs[level],
7594                                                 &wc->flags[level]);
7595                         if (ret < 0) {
7596                                 err = ret;
7597                                 goto out_end_trans;
7598                         }
7599                         BUG_ON(wc->refs[level] == 0);
7600
7601                         if (level == root_item->drop_level)
7602                                 break;
7603
7604                         btrfs_tree_unlock(path->nodes[level]);
7605                         path->locks[level] = 0;
7606                         WARN_ON(wc->refs[level] != 1);
7607                         level--;
7608                 }
7609         }
7610
7611         wc->level = level;
7612         wc->shared_level = -1;
7613         wc->stage = DROP_REFERENCE;
7614         wc->update_ref = update_ref;
7615         wc->keep_locks = 0;
7616         wc->for_reloc = for_reloc;
7617         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7618
7619         while (1) {
7620
7621                 ret = walk_down_tree(trans, root, path, wc);
7622                 if (ret < 0) {
7623                         err = ret;
7624                         break;
7625                 }
7626
7627                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7628                 if (ret < 0) {
7629                         err = ret;
7630                         break;
7631                 }
7632
7633                 if (ret > 0) {
7634                         BUG_ON(wc->stage != DROP_REFERENCE);
7635                         break;
7636                 }
7637
7638                 if (wc->stage == DROP_REFERENCE) {
7639                         level = wc->level;
7640                         btrfs_node_key(path->nodes[level],
7641                                        &root_item->drop_progress,
7642                                        path->slots[level]);
7643                         root_item->drop_level = level;
7644                 }
7645
7646                 BUG_ON(wc->level == 0);
7647                 if (btrfs_should_end_transaction(trans, tree_root) ||
7648                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
7649                         ret = btrfs_update_root(trans, tree_root,
7650                                                 &root->root_key,
7651                                                 root_item);
7652                         if (ret) {
7653                                 btrfs_abort_transaction(trans, tree_root, ret);
7654                                 err = ret;
7655                                 goto out_end_trans;
7656                         }
7657
7658                         btrfs_end_transaction_throttle(trans, tree_root);
7659                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
7660                                 pr_debug("BTRFS: drop snapshot early exit\n");
7661                                 err = -EAGAIN;
7662                                 goto out_free;
7663                         }
7664
7665                         trans = btrfs_start_transaction(tree_root, 0);
7666                         if (IS_ERR(trans)) {
7667                                 err = PTR_ERR(trans);
7668                                 goto out_free;
7669                         }
7670                         if (block_rsv)
7671                                 trans->block_rsv = block_rsv;
7672                 }
7673         }
7674         btrfs_release_path(path);
7675         if (err)
7676                 goto out_end_trans;
7677
7678         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7679         if (ret) {
7680                 btrfs_abort_transaction(trans, tree_root, ret);
7681                 goto out_end_trans;
7682         }
7683
7684         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7685                 ret = btrfs_find_root(tree_root, &root->root_key, path,
7686                                       NULL, NULL);
7687                 if (ret < 0) {
7688                         btrfs_abort_transaction(trans, tree_root, ret);
7689                         err = ret;
7690                         goto out_end_trans;
7691                 } else if (ret > 0) {
7692                         /* if we fail to delete the orphan item this time
7693                          * around, it'll get picked up the next time.
7694                          *
7695                          * The most common failure here is just -ENOENT.
7696                          */
7697                         btrfs_del_orphan_item(trans, tree_root,
7698                                               root->root_key.objectid);
7699                 }
7700         }
7701
7702         if (root->in_radix) {
7703                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
7704         } else {
7705                 free_extent_buffer(root->node);
7706                 free_extent_buffer(root->commit_root);
7707                 btrfs_put_fs_root(root);
7708         }
7709         root_dropped = true;
7710 out_end_trans:
7711         btrfs_end_transaction_throttle(trans, tree_root);
7712 out_free:
7713         kfree(wc);
7714         btrfs_free_path(path);
7715 out:
7716         /*
7717          * So if we need to stop dropping the snapshot for whatever reason we
7718          * need to make sure to add it back to the dead root list so that we
7719          * keep trying to do the work later.  This also cleans up roots if we
7720          * don't have it in the radix (like when we recover after a power fail
7721          * or unmount) so we don't leak memory.
7722          */
7723         if (!for_reloc && root_dropped == false)
7724                 btrfs_add_dead_root(root);
7725         if (err && err != -EAGAIN)
7726                 btrfs_std_error(root->fs_info, err);
7727         return err;
7728 }
7729
7730 /*
7731  * drop subtree rooted at tree block 'node'.
7732  *
7733  * NOTE: this function will unlock and release tree block 'node'
7734  * only used by relocation code
7735  */
7736 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7737                         struct btrfs_root *root,
7738                         struct extent_buffer *node,
7739                         struct extent_buffer *parent)
7740 {
7741         struct btrfs_path *path;
7742         struct walk_control *wc;
7743         int level;
7744         int parent_level;
7745         int ret = 0;
7746         int wret;
7747
7748         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7749
7750         path = btrfs_alloc_path();
7751         if (!path)
7752                 return -ENOMEM;
7753
7754         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7755         if (!wc) {
7756                 btrfs_free_path(path);
7757                 return -ENOMEM;
7758         }
7759
7760         btrfs_assert_tree_locked(parent);
7761         parent_level = btrfs_header_level(parent);
7762         extent_buffer_get(parent);
7763         path->nodes[parent_level] = parent;
7764         path->slots[parent_level] = btrfs_header_nritems(parent);
7765
7766         btrfs_assert_tree_locked(node);
7767         level = btrfs_header_level(node);
7768         path->nodes[level] = node;
7769         path->slots[level] = 0;
7770         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7771
7772         wc->refs[parent_level] = 1;
7773         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7774         wc->level = level;
7775         wc->shared_level = -1;
7776         wc->stage = DROP_REFERENCE;
7777         wc->update_ref = 0;
7778         wc->keep_locks = 1;
7779         wc->for_reloc = 1;
7780         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7781
7782         while (1) {
7783                 wret = walk_down_tree(trans, root, path, wc);
7784                 if (wret < 0) {
7785                         ret = wret;
7786                         break;
7787                 }
7788
7789                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7790                 if (wret < 0)
7791                         ret = wret;
7792                 if (wret != 0)
7793                         break;
7794         }
7795
7796         kfree(wc);
7797         btrfs_free_path(path);
7798         return ret;
7799 }
7800
7801 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7802 {
7803         u64 num_devices;
7804         u64 stripped;
7805
7806         /*
7807          * if restripe for this chunk_type is on pick target profile and
7808          * return, otherwise do the usual balance
7809          */
7810         stripped = get_restripe_target(root->fs_info, flags);
7811         if (stripped)
7812                 return extended_to_chunk(stripped);
7813
7814         /*
7815          * we add in the count of missing devices because we want
7816          * to make sure that any RAID levels on a degraded FS
7817          * continue to be honored.
7818          */
7819         num_devices = root->fs_info->fs_devices->rw_devices +
7820                 root->fs_info->fs_devices->missing_devices;
7821
7822         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7823                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
7824                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7825
7826         if (num_devices == 1) {
7827                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7828                 stripped = flags & ~stripped;
7829
7830                 /* turn raid0 into single device chunks */
7831                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7832                         return stripped;
7833
7834                 /* turn mirroring into duplication */
7835                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7836                              BTRFS_BLOCK_GROUP_RAID10))
7837                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7838         } else {
7839                 /* they already had raid on here, just return */
7840                 if (flags & stripped)
7841                         return flags;
7842
7843                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7844                 stripped = flags & ~stripped;
7845
7846                 /* switch duplicated blocks with raid1 */
7847                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7848                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7849
7850                 /* this is drive concat, leave it alone */
7851         }
7852
7853         return flags;
7854 }
7855
7856 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7857 {
7858         struct btrfs_space_info *sinfo = cache->space_info;
7859         u64 num_bytes;
7860         u64 min_allocable_bytes;
7861         int ret = -ENOSPC;
7862
7863
7864         /*
7865          * We need some metadata space and system metadata space for
7866          * allocating chunks in some corner cases until we force to set
7867          * it to be readonly.
7868          */
7869         if ((sinfo->flags &
7870              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7871             !force)
7872                 min_allocable_bytes = 1 * 1024 * 1024;
7873         else
7874                 min_allocable_bytes = 0;
7875
7876         spin_lock(&sinfo->lock);
7877         spin_lock(&cache->lock);
7878
7879         if (cache->ro) {
7880                 ret = 0;
7881                 goto out;
7882         }
7883
7884         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7885                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7886
7887         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7888             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7889             min_allocable_bytes <= sinfo->total_bytes) {
7890                 sinfo->bytes_readonly += num_bytes;
7891                 cache->ro = 1;
7892                 ret = 0;
7893         }
7894 out:
7895         spin_unlock(&cache->lock);
7896         spin_unlock(&sinfo->lock);
7897         return ret;
7898 }
7899
7900 int btrfs_set_block_group_ro(struct btrfs_root *root,
7901                              struct btrfs_block_group_cache *cache)
7902
7903 {
7904         struct btrfs_trans_handle *trans;
7905         u64 alloc_flags;
7906         int ret;
7907
7908         BUG_ON(cache->ro);
7909
7910         trans = btrfs_join_transaction(root);
7911         if (IS_ERR(trans))
7912                 return PTR_ERR(trans);
7913
7914         alloc_flags = update_block_group_flags(root, cache->flags);
7915         if (alloc_flags != cache->flags) {
7916                 ret = do_chunk_alloc(trans, root, alloc_flags,
7917                                      CHUNK_ALLOC_FORCE);
7918                 if (ret < 0)
7919                         goto out;
7920         }
7921
7922         ret = set_block_group_ro(cache, 0);
7923         if (!ret)
7924                 goto out;
7925         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7926         ret = do_chunk_alloc(trans, root, alloc_flags,
7927                              CHUNK_ALLOC_FORCE);
7928         if (ret < 0)
7929                 goto out;
7930         ret = set_block_group_ro(cache, 0);
7931 out:
7932         btrfs_end_transaction(trans, root);
7933         return ret;
7934 }
7935
7936 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7937                             struct btrfs_root *root, u64 type)
7938 {
7939         u64 alloc_flags = get_alloc_profile(root, type);
7940         return do_chunk_alloc(trans, root, alloc_flags,
7941                               CHUNK_ALLOC_FORCE);
7942 }
7943
7944 /*
7945  * helper to account the unused space of all the readonly block group in the
7946  * list. takes mirrors into account.
7947  */
7948 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7949 {
7950         struct btrfs_block_group_cache *block_group;
7951         u64 free_bytes = 0;
7952         int factor;
7953
7954         list_for_each_entry(block_group, groups_list, list) {
7955                 spin_lock(&block_group->lock);
7956
7957                 if (!block_group->ro) {
7958                         spin_unlock(&block_group->lock);
7959                         continue;
7960                 }
7961
7962                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7963                                           BTRFS_BLOCK_GROUP_RAID10 |
7964                                           BTRFS_BLOCK_GROUP_DUP))
7965                         factor = 2;
7966                 else
7967                         factor = 1;
7968
7969                 free_bytes += (block_group->key.offset -
7970                                btrfs_block_group_used(&block_group->item)) *
7971                                factor;
7972
7973                 spin_unlock(&block_group->lock);
7974         }
7975
7976         return free_bytes;
7977 }
7978
7979 /*
7980  * helper to account the unused space of all the readonly block group in the
7981  * space_info. takes mirrors into account.
7982  */
7983 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7984 {
7985         int i;
7986         u64 free_bytes = 0;
7987
7988         spin_lock(&sinfo->lock);
7989
7990         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7991                 if (!list_empty(&sinfo->block_groups[i]))
7992                         free_bytes += __btrfs_get_ro_block_group_free_space(
7993                                                 &sinfo->block_groups[i]);
7994
7995         spin_unlock(&sinfo->lock);
7996
7997         return free_bytes;
7998 }
7999
8000 void btrfs_set_block_group_rw(struct btrfs_root *root,
8001                               struct btrfs_block_group_cache *cache)
8002 {
8003         struct btrfs_space_info *sinfo = cache->space_info;
8004         u64 num_bytes;
8005
8006         BUG_ON(!cache->ro);
8007
8008         spin_lock(&sinfo->lock);
8009         spin_lock(&cache->lock);
8010         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8011                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8012         sinfo->bytes_readonly -= num_bytes;
8013         cache->ro = 0;
8014         spin_unlock(&cache->lock);
8015         spin_unlock(&sinfo->lock);
8016 }
8017
8018 /*
8019  * checks to see if its even possible to relocate this block group.
8020  *
8021  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8022  * ok to go ahead and try.
8023  */
8024 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8025 {
8026         struct btrfs_block_group_cache *block_group;
8027         struct btrfs_space_info *space_info;
8028         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8029         struct btrfs_device *device;
8030         struct btrfs_trans_handle *trans;
8031         u64 min_free;
8032         u64 dev_min = 1;
8033         u64 dev_nr = 0;
8034         u64 target;
8035         int index;
8036         int full = 0;
8037         int ret = 0;
8038
8039         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8040
8041         /* odd, couldn't find the block group, leave it alone */
8042         if (!block_group)
8043                 return -1;
8044
8045         min_free = btrfs_block_group_used(&block_group->item);
8046
8047         /* no bytes used, we're good */
8048         if (!min_free)
8049                 goto out;
8050
8051         space_info = block_group->space_info;
8052         spin_lock(&space_info->lock);
8053
8054         full = space_info->full;
8055
8056         /*
8057          * if this is the last block group we have in this space, we can't
8058          * relocate it unless we're able to allocate a new chunk below.
8059          *
8060          * Otherwise, we need to make sure we have room in the space to handle
8061          * all of the extents from this block group.  If we can, we're good
8062          */
8063         if ((space_info->total_bytes != block_group->key.offset) &&
8064             (space_info->bytes_used + space_info->bytes_reserved +
8065              space_info->bytes_pinned + space_info->bytes_readonly +
8066              min_free < space_info->total_bytes)) {
8067                 spin_unlock(&space_info->lock);
8068                 goto out;
8069         }
8070         spin_unlock(&space_info->lock);
8071
8072         /*
8073          * ok we don't have enough space, but maybe we have free space on our
8074          * devices to allocate new chunks for relocation, so loop through our
8075          * alloc devices and guess if we have enough space.  if this block
8076          * group is going to be restriped, run checks against the target
8077          * profile instead of the current one.
8078          */
8079         ret = -1;
8080
8081         /*
8082          * index:
8083          *      0: raid10
8084          *      1: raid1
8085          *      2: dup
8086          *      3: raid0
8087          *      4: single
8088          */
8089         target = get_restripe_target(root->fs_info, block_group->flags);
8090         if (target) {
8091                 index = __get_raid_index(extended_to_chunk(target));
8092         } else {
8093                 /*
8094                  * this is just a balance, so if we were marked as full
8095                  * we know there is no space for a new chunk
8096                  */
8097                 if (full)
8098                         goto out;
8099
8100                 index = get_block_group_index(block_group);
8101         }
8102
8103         if (index == BTRFS_RAID_RAID10) {
8104                 dev_min = 4;
8105                 /* Divide by 2 */
8106                 min_free >>= 1;
8107         } else if (index == BTRFS_RAID_RAID1) {
8108                 dev_min = 2;
8109         } else if (index == BTRFS_RAID_DUP) {
8110                 /* Multiply by 2 */
8111                 min_free <<= 1;
8112         } else if (index == BTRFS_RAID_RAID0) {
8113                 dev_min = fs_devices->rw_devices;
8114                 do_div(min_free, dev_min);
8115         }
8116
8117         /* We need to do this so that we can look at pending chunks */
8118         trans = btrfs_join_transaction(root);
8119         if (IS_ERR(trans)) {
8120                 ret = PTR_ERR(trans);
8121                 goto out;
8122         }
8123
8124         mutex_lock(&root->fs_info->chunk_mutex);
8125         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8126                 u64 dev_offset;
8127
8128                 /*
8129                  * check to make sure we can actually find a chunk with enough
8130                  * space to fit our block group in.
8131                  */
8132                 if (device->total_bytes > device->bytes_used + min_free &&
8133                     !device->is_tgtdev_for_dev_replace) {
8134                         ret = find_free_dev_extent(trans, device, min_free,
8135                                                    &dev_offset, NULL);
8136                         if (!ret)
8137                                 dev_nr++;
8138
8139                         if (dev_nr >= dev_min)
8140                                 break;
8141
8142                         ret = -1;
8143                 }
8144         }
8145         mutex_unlock(&root->fs_info->chunk_mutex);
8146         btrfs_end_transaction(trans, root);
8147 out:
8148         btrfs_put_block_group(block_group);
8149         return ret;
8150 }
8151
8152 static int find_first_block_group(struct btrfs_root *root,
8153                 struct btrfs_path *path, struct btrfs_key *key)
8154 {
8155         int ret = 0;
8156         struct btrfs_key found_key;
8157         struct extent_buffer *leaf;
8158         int slot;
8159
8160         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
8161         if (ret < 0)
8162                 goto out;
8163
8164         while (1) {
8165                 slot = path->slots[0];
8166                 leaf = path->nodes[0];
8167                 if (slot >= btrfs_header_nritems(leaf)) {
8168                         ret = btrfs_next_leaf(root, path);
8169                         if (ret == 0)
8170                                 continue;
8171                         if (ret < 0)
8172                                 goto out;
8173                         break;
8174                 }
8175                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
8176
8177                 if (found_key.objectid >= key->objectid &&
8178                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
8179                         ret = 0;
8180                         goto out;
8181                 }
8182                 path->slots[0]++;
8183         }
8184 out:
8185         return ret;
8186 }
8187
8188 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
8189 {
8190         struct btrfs_block_group_cache *block_group;
8191         u64 last = 0;
8192
8193         while (1) {
8194                 struct inode *inode;
8195
8196                 block_group = btrfs_lookup_first_block_group(info, last);
8197                 while (block_group) {
8198                         spin_lock(&block_group->lock);
8199                         if (block_group->iref)
8200                                 break;
8201                         spin_unlock(&block_group->lock);
8202                         block_group = next_block_group(info->tree_root,
8203                                                        block_group);
8204                 }
8205                 if (!block_group) {
8206                         if (last == 0)
8207                                 break;
8208                         last = 0;
8209                         continue;
8210                 }
8211
8212                 inode = block_group->inode;
8213                 block_group->iref = 0;
8214                 block_group->inode = NULL;
8215                 spin_unlock(&block_group->lock);
8216                 iput(inode);
8217                 last = block_group->key.objectid + block_group->key.offset;
8218                 btrfs_put_block_group(block_group);
8219         }
8220 }
8221
8222 int btrfs_free_block_groups(struct btrfs_fs_info *info)
8223 {
8224         struct btrfs_block_group_cache *block_group;
8225         struct btrfs_space_info *space_info;
8226         struct btrfs_caching_control *caching_ctl;
8227         struct rb_node *n;
8228
8229         down_write(&info->extent_commit_sem);
8230         while (!list_empty(&info->caching_block_groups)) {
8231                 caching_ctl = list_entry(info->caching_block_groups.next,
8232                                          struct btrfs_caching_control, list);
8233                 list_del(&caching_ctl->list);
8234                 put_caching_control(caching_ctl);
8235         }
8236         up_write(&info->extent_commit_sem);
8237
8238         spin_lock(&info->block_group_cache_lock);
8239         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8240                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8241                                        cache_node);
8242                 rb_erase(&block_group->cache_node,
8243                          &info->block_group_cache_tree);
8244                 spin_unlock(&info->block_group_cache_lock);
8245
8246                 down_write(&block_group->space_info->groups_sem);
8247                 list_del(&block_group->list);
8248                 up_write(&block_group->space_info->groups_sem);
8249
8250                 if (block_group->cached == BTRFS_CACHE_STARTED)
8251                         wait_block_group_cache_done(block_group);
8252
8253                 /*
8254                  * We haven't cached this block group, which means we could
8255                  * possibly have excluded extents on this block group.
8256                  */
8257                 if (block_group->cached == BTRFS_CACHE_NO ||
8258                     block_group->cached == BTRFS_CACHE_ERROR)
8259                         free_excluded_extents(info->extent_root, block_group);
8260
8261                 btrfs_remove_free_space_cache(block_group);
8262                 btrfs_put_block_group(block_group);
8263
8264                 spin_lock(&info->block_group_cache_lock);
8265         }
8266         spin_unlock(&info->block_group_cache_lock);
8267
8268         /* now that all the block groups are freed, go through and
8269          * free all the space_info structs.  This is only called during
8270          * the final stages of unmount, and so we know nobody is
8271          * using them.  We call synchronize_rcu() once before we start,
8272          * just to be on the safe side.
8273          */
8274         synchronize_rcu();
8275
8276         release_global_block_rsv(info);
8277
8278         while (!list_empty(&info->space_info)) {
8279                 int i;
8280
8281                 space_info = list_entry(info->space_info.next,
8282                                         struct btrfs_space_info,
8283                                         list);
8284                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8285                         if (WARN_ON(space_info->bytes_pinned > 0 ||
8286                             space_info->bytes_reserved > 0 ||
8287                             space_info->bytes_may_use > 0)) {
8288                                 dump_space_info(space_info, 0, 0);
8289                         }
8290                 }
8291                 list_del(&space_info->list);
8292                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
8293                         struct kobject *kobj;
8294                         kobj = &space_info->block_group_kobjs[i];
8295                         if (kobj->parent) {
8296                                 kobject_del(kobj);
8297                                 kobject_put(kobj);
8298                         }
8299                 }
8300                 kobject_del(&space_info->kobj);
8301                 kobject_put(&space_info->kobj);
8302         }
8303         return 0;
8304 }
8305
8306 static void __link_block_group(struct btrfs_space_info *space_info,
8307                                struct btrfs_block_group_cache *cache)
8308 {
8309         int index = get_block_group_index(cache);
8310
8311         down_write(&space_info->groups_sem);
8312         if (list_empty(&space_info->block_groups[index])) {
8313                 struct kobject *kobj = &space_info->block_group_kobjs[index];
8314                 int ret;
8315
8316                 kobject_get(&space_info->kobj); /* put in release */
8317                 ret = kobject_add(kobj, &space_info->kobj, "%s",
8318                                   get_raid_name(index));
8319                 if (ret) {
8320                         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
8321                         kobject_put(&space_info->kobj);
8322                 }
8323         }
8324         list_add_tail(&cache->list, &space_info->block_groups[index]);
8325         up_write(&space_info->groups_sem);
8326 }
8327
8328 int btrfs_read_block_groups(struct btrfs_root *root)
8329 {
8330         struct btrfs_path *path;
8331         int ret;
8332         struct btrfs_block_group_cache *cache;
8333         struct btrfs_fs_info *info = root->fs_info;
8334         struct btrfs_space_info *space_info;
8335         struct btrfs_key key;
8336         struct btrfs_key found_key;
8337         struct extent_buffer *leaf;
8338         int need_clear = 0;
8339         u64 cache_gen;
8340
8341         root = info->extent_root;
8342         key.objectid = 0;
8343         key.offset = 0;
8344         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
8345         path = btrfs_alloc_path();
8346         if (!path)
8347                 return -ENOMEM;
8348         path->reada = 1;
8349
8350         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
8351         if (btrfs_test_opt(root, SPACE_CACHE) &&
8352             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
8353                 need_clear = 1;
8354         if (btrfs_test_opt(root, CLEAR_CACHE))
8355                 need_clear = 1;
8356
8357         while (1) {
8358                 ret = find_first_block_group(root, path, &key);
8359                 if (ret > 0)
8360                         break;
8361                 if (ret != 0)
8362                         goto error;
8363                 leaf = path->nodes[0];
8364                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8365                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
8366                 if (!cache) {
8367                         ret = -ENOMEM;
8368                         goto error;
8369                 }
8370                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8371                                                 GFP_NOFS);
8372                 if (!cache->free_space_ctl) {
8373                         kfree(cache);
8374                         ret = -ENOMEM;
8375                         goto error;
8376                 }
8377
8378                 atomic_set(&cache->count, 1);
8379                 spin_lock_init(&cache->lock);
8380                 cache->fs_info = info;
8381                 INIT_LIST_HEAD(&cache->list);
8382                 INIT_LIST_HEAD(&cache->cluster_list);
8383
8384                 if (need_clear) {
8385                         /*
8386                          * When we mount with old space cache, we need to
8387                          * set BTRFS_DC_CLEAR and set dirty flag.
8388                          *
8389                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
8390                          *    truncate the old free space cache inode and
8391                          *    setup a new one.
8392                          * b) Setting 'dirty flag' makes sure that we flush
8393                          *    the new space cache info onto disk.
8394                          */
8395                         cache->disk_cache_state = BTRFS_DC_CLEAR;
8396                         if (btrfs_test_opt(root, SPACE_CACHE))
8397                                 cache->dirty = 1;
8398                 }
8399
8400                 read_extent_buffer(leaf, &cache->item,
8401                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
8402                                    sizeof(cache->item));
8403                 memcpy(&cache->key, &found_key, sizeof(found_key));
8404
8405                 key.objectid = found_key.objectid + found_key.offset;
8406                 btrfs_release_path(path);
8407                 cache->flags = btrfs_block_group_flags(&cache->item);
8408                 cache->sectorsize = root->sectorsize;
8409                 cache->full_stripe_len = btrfs_full_stripe_len(root,
8410                                                &root->fs_info->mapping_tree,
8411                                                found_key.objectid);
8412                 btrfs_init_free_space_ctl(cache);
8413
8414                 /*
8415                  * We need to exclude the super stripes now so that the space
8416                  * info has super bytes accounted for, otherwise we'll think
8417                  * we have more space than we actually do.
8418                  */
8419                 ret = exclude_super_stripes(root, cache);
8420                 if (ret) {
8421                         /*
8422                          * We may have excluded something, so call this just in
8423                          * case.
8424                          */
8425                         free_excluded_extents(root, cache);
8426                         kfree(cache->free_space_ctl);
8427                         kfree(cache);
8428                         goto error;
8429                 }
8430
8431                 /*
8432                  * check for two cases, either we are full, and therefore
8433                  * don't need to bother with the caching work since we won't
8434                  * find any space, or we are empty, and we can just add all
8435                  * the space in and be done with it.  This saves us _alot_ of
8436                  * time, particularly in the full case.
8437                  */
8438                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
8439                         cache->last_byte_to_unpin = (u64)-1;
8440                         cache->cached = BTRFS_CACHE_FINISHED;
8441                         free_excluded_extents(root, cache);
8442                 } else if (btrfs_block_group_used(&cache->item) == 0) {
8443                         cache->last_byte_to_unpin = (u64)-1;
8444                         cache->cached = BTRFS_CACHE_FINISHED;
8445                         add_new_free_space(cache, root->fs_info,
8446                                            found_key.objectid,
8447                                            found_key.objectid +
8448                                            found_key.offset);
8449                         free_excluded_extents(root, cache);
8450                 }
8451
8452                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8453                 if (ret) {
8454                         btrfs_remove_free_space_cache(cache);
8455                         btrfs_put_block_group(cache);
8456                         goto error;
8457                 }
8458
8459                 ret = update_space_info(info, cache->flags, found_key.offset,
8460                                         btrfs_block_group_used(&cache->item),
8461                                         &space_info);
8462                 if (ret) {
8463                         btrfs_remove_free_space_cache(cache);
8464                         spin_lock(&info->block_group_cache_lock);
8465                         rb_erase(&cache->cache_node,
8466                                  &info->block_group_cache_tree);
8467                         spin_unlock(&info->block_group_cache_lock);
8468                         btrfs_put_block_group(cache);
8469                         goto error;
8470                 }
8471
8472                 cache->space_info = space_info;
8473                 spin_lock(&cache->space_info->lock);
8474                 cache->space_info->bytes_readonly += cache->bytes_super;
8475                 spin_unlock(&cache->space_info->lock);
8476
8477                 __link_block_group(space_info, cache);
8478
8479                 set_avail_alloc_bits(root->fs_info, cache->flags);
8480                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8481                         set_block_group_ro(cache, 1);
8482         }
8483
8484         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8485                 if (!(get_alloc_profile(root, space_info->flags) &
8486                       (BTRFS_BLOCK_GROUP_RAID10 |
8487                        BTRFS_BLOCK_GROUP_RAID1 |
8488                        BTRFS_BLOCK_GROUP_RAID5 |
8489                        BTRFS_BLOCK_GROUP_RAID6 |
8490                        BTRFS_BLOCK_GROUP_DUP)))
8491                         continue;
8492                 /*
8493                  * avoid allocating from un-mirrored block group if there are
8494                  * mirrored block groups.
8495                  */
8496                 list_for_each_entry(cache,
8497                                 &space_info->block_groups[BTRFS_RAID_RAID0],
8498                                 list)
8499                         set_block_group_ro(cache, 1);
8500                 list_for_each_entry(cache,
8501                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
8502                                 list)
8503                         set_block_group_ro(cache, 1);
8504         }
8505
8506         init_global_block_rsv(info);
8507         ret = 0;
8508 error:
8509         btrfs_free_path(path);
8510         return ret;
8511 }
8512
8513 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
8514                                        struct btrfs_root *root)
8515 {
8516         struct btrfs_block_group_cache *block_group, *tmp;
8517         struct btrfs_root *extent_root = root->fs_info->extent_root;
8518         struct btrfs_block_group_item item;
8519         struct btrfs_key key;
8520         int ret = 0;
8521
8522         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
8523                                  new_bg_list) {
8524                 list_del_init(&block_group->new_bg_list);
8525
8526                 if (ret)
8527                         continue;
8528
8529                 spin_lock(&block_group->lock);
8530                 memcpy(&item, &block_group->item, sizeof(item));
8531                 memcpy(&key, &block_group->key, sizeof(key));
8532                 spin_unlock(&block_group->lock);
8533
8534                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
8535                                         sizeof(item));
8536                 if (ret)
8537                         btrfs_abort_transaction(trans, extent_root, ret);
8538                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
8539                                                key.objectid, key.offset);
8540                 if (ret)
8541                         btrfs_abort_transaction(trans, extent_root, ret);
8542         }
8543 }
8544
8545 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8546                            struct btrfs_root *root, u64 bytes_used,
8547                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8548                            u64 size)
8549 {
8550         int ret;
8551         struct btrfs_root *extent_root;
8552         struct btrfs_block_group_cache *cache;
8553
8554         extent_root = root->fs_info->extent_root;
8555
8556         root->fs_info->last_trans_log_full_commit = trans->transid;
8557
8558         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8559         if (!cache)
8560                 return -ENOMEM;
8561         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8562                                         GFP_NOFS);
8563         if (!cache->free_space_ctl) {
8564                 kfree(cache);
8565                 return -ENOMEM;
8566         }
8567
8568         cache->key.objectid = chunk_offset;
8569         cache->key.offset = size;
8570         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8571         cache->sectorsize = root->sectorsize;
8572         cache->fs_info = root->fs_info;
8573         cache->full_stripe_len = btrfs_full_stripe_len(root,
8574                                                &root->fs_info->mapping_tree,
8575                                                chunk_offset);
8576
8577         atomic_set(&cache->count, 1);
8578         spin_lock_init(&cache->lock);
8579         INIT_LIST_HEAD(&cache->list);
8580         INIT_LIST_HEAD(&cache->cluster_list);
8581         INIT_LIST_HEAD(&cache->new_bg_list);
8582
8583         btrfs_init_free_space_ctl(cache);
8584
8585         btrfs_set_block_group_used(&cache->item, bytes_used);
8586         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8587         cache->flags = type;
8588         btrfs_set_block_group_flags(&cache->item, type);
8589
8590         cache->last_byte_to_unpin = (u64)-1;
8591         cache->cached = BTRFS_CACHE_FINISHED;
8592         ret = exclude_super_stripes(root, cache);
8593         if (ret) {
8594                 /*
8595                  * We may have excluded something, so call this just in
8596                  * case.
8597                  */
8598                 free_excluded_extents(root, cache);
8599                 kfree(cache->free_space_ctl);
8600                 kfree(cache);
8601                 return ret;
8602         }
8603
8604         add_new_free_space(cache, root->fs_info, chunk_offset,
8605                            chunk_offset + size);
8606
8607         free_excluded_extents(root, cache);
8608
8609         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8610         if (ret) {
8611                 btrfs_remove_free_space_cache(cache);
8612                 btrfs_put_block_group(cache);
8613                 return ret;
8614         }
8615
8616         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8617                                 &cache->space_info);
8618         if (ret) {
8619                 btrfs_remove_free_space_cache(cache);
8620                 spin_lock(&root->fs_info->block_group_cache_lock);
8621                 rb_erase(&cache->cache_node,
8622                          &root->fs_info->block_group_cache_tree);
8623                 spin_unlock(&root->fs_info->block_group_cache_lock);
8624                 btrfs_put_block_group(cache);
8625                 return ret;
8626         }
8627         update_global_block_rsv(root->fs_info);
8628
8629         spin_lock(&cache->space_info->lock);
8630         cache->space_info->bytes_readonly += cache->bytes_super;
8631         spin_unlock(&cache->space_info->lock);
8632
8633         __link_block_group(cache->space_info, cache);
8634
8635         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
8636
8637         set_avail_alloc_bits(extent_root->fs_info, type);
8638
8639         return 0;
8640 }
8641
8642 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
8643 {
8644         u64 extra_flags = chunk_to_extended(flags) &
8645                                 BTRFS_EXTENDED_PROFILE_MASK;
8646
8647         write_seqlock(&fs_info->profiles_lock);
8648         if (flags & BTRFS_BLOCK_GROUP_DATA)
8649                 fs_info->avail_data_alloc_bits &= ~extra_flags;
8650         if (flags & BTRFS_BLOCK_GROUP_METADATA)
8651                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
8652         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
8653                 fs_info->avail_system_alloc_bits &= ~extra_flags;
8654         write_sequnlock(&fs_info->profiles_lock);
8655 }
8656
8657 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8658                              struct btrfs_root *root, u64 group_start)
8659 {
8660         struct btrfs_path *path;
8661         struct btrfs_block_group_cache *block_group;
8662         struct btrfs_free_cluster *cluster;
8663         struct btrfs_root *tree_root = root->fs_info->tree_root;
8664         struct btrfs_key key;
8665         struct inode *inode;
8666         int ret;
8667         int index;
8668         int factor;
8669
8670         root = root->fs_info->extent_root;
8671
8672         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8673         BUG_ON(!block_group);
8674         BUG_ON(!block_group->ro);
8675
8676         /*
8677          * Free the reserved super bytes from this block group before
8678          * remove it.
8679          */
8680         free_excluded_extents(root, block_group);
8681
8682         memcpy(&key, &block_group->key, sizeof(key));
8683         index = get_block_group_index(block_group);
8684         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
8685                                   BTRFS_BLOCK_GROUP_RAID1 |
8686                                   BTRFS_BLOCK_GROUP_RAID10))
8687                 factor = 2;
8688         else
8689                 factor = 1;
8690
8691         /* make sure this block group isn't part of an allocation cluster */
8692         cluster = &root->fs_info->data_alloc_cluster;
8693         spin_lock(&cluster->refill_lock);
8694         btrfs_return_cluster_to_free_space(block_group, cluster);
8695         spin_unlock(&cluster->refill_lock);
8696
8697         /*
8698          * make sure this block group isn't part of a metadata
8699          * allocation cluster
8700          */
8701         cluster = &root->fs_info->meta_alloc_cluster;
8702         spin_lock(&cluster->refill_lock);
8703         btrfs_return_cluster_to_free_space(block_group, cluster);
8704         spin_unlock(&cluster->refill_lock);
8705
8706         path = btrfs_alloc_path();
8707         if (!path) {
8708                 ret = -ENOMEM;
8709                 goto out;
8710         }
8711
8712         inode = lookup_free_space_inode(tree_root, block_group, path);
8713         if (!IS_ERR(inode)) {
8714                 ret = btrfs_orphan_add(trans, inode);
8715                 if (ret) {
8716                         btrfs_add_delayed_iput(inode);
8717                         goto out;
8718                 }
8719                 clear_nlink(inode);
8720                 /* One for the block groups ref */
8721                 spin_lock(&block_group->lock);
8722                 if (block_group->iref) {
8723                         block_group->iref = 0;
8724                         block_group->inode = NULL;
8725                         spin_unlock(&block_group->lock);
8726                         iput(inode);
8727                 } else {
8728                         spin_unlock(&block_group->lock);
8729                 }
8730                 /* One for our lookup ref */
8731                 btrfs_add_delayed_iput(inode);
8732         }
8733
8734         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8735         key.offset = block_group->key.objectid;
8736         key.type = 0;
8737
8738         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8739         if (ret < 0)
8740                 goto out;
8741         if (ret > 0)
8742                 btrfs_release_path(path);
8743         if (ret == 0) {
8744                 ret = btrfs_del_item(trans, tree_root, path);
8745                 if (ret)
8746                         goto out;
8747                 btrfs_release_path(path);
8748         }
8749
8750         spin_lock(&root->fs_info->block_group_cache_lock);
8751         rb_erase(&block_group->cache_node,
8752                  &root->fs_info->block_group_cache_tree);
8753
8754         if (root->fs_info->first_logical_byte == block_group->key.objectid)
8755                 root->fs_info->first_logical_byte = (u64)-1;
8756         spin_unlock(&root->fs_info->block_group_cache_lock);
8757
8758         down_write(&block_group->space_info->groups_sem);
8759         /*
8760          * we must use list_del_init so people can check to see if they
8761          * are still on the list after taking the semaphore
8762          */
8763         list_del_init(&block_group->list);
8764         if (list_empty(&block_group->space_info->block_groups[index])) {
8765                 kobject_del(&block_group->space_info->block_group_kobjs[index]);
8766                 kobject_put(&block_group->space_info->block_group_kobjs[index]);
8767                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8768         }
8769         up_write(&block_group->space_info->groups_sem);
8770
8771         if (block_group->cached == BTRFS_CACHE_STARTED)
8772                 wait_block_group_cache_done(block_group);
8773
8774         btrfs_remove_free_space_cache(block_group);
8775
8776         spin_lock(&block_group->space_info->lock);
8777         block_group->space_info->total_bytes -= block_group->key.offset;
8778         block_group->space_info->bytes_readonly -= block_group->key.offset;
8779         block_group->space_info->disk_total -= block_group->key.offset * factor;
8780         spin_unlock(&block_group->space_info->lock);
8781
8782         memcpy(&key, &block_group->key, sizeof(key));
8783
8784         btrfs_clear_space_info_full(root->fs_info);
8785
8786         btrfs_put_block_group(block_group);
8787         btrfs_put_block_group(block_group);
8788
8789         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8790         if (ret > 0)
8791                 ret = -EIO;
8792         if (ret < 0)
8793                 goto out;
8794
8795         ret = btrfs_del_item(trans, root, path);
8796 out:
8797         btrfs_free_path(path);
8798         return ret;
8799 }
8800
8801 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8802 {
8803         struct btrfs_space_info *space_info;
8804         struct btrfs_super_block *disk_super;
8805         u64 features;
8806         u64 flags;
8807         int mixed = 0;
8808         int ret;
8809
8810         disk_super = fs_info->super_copy;
8811         if (!btrfs_super_root(disk_super))
8812                 return 1;
8813
8814         features = btrfs_super_incompat_flags(disk_super);
8815         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8816                 mixed = 1;
8817
8818         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8819         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8820         if (ret)
8821                 goto out;
8822
8823         if (mixed) {
8824                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8825                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8826         } else {
8827                 flags = BTRFS_BLOCK_GROUP_METADATA;
8828                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8829                 if (ret)
8830                         goto out;
8831
8832                 flags = BTRFS_BLOCK_GROUP_DATA;
8833                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8834         }
8835 out:
8836         return ret;
8837 }
8838
8839 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8840 {
8841         return unpin_extent_range(root, start, end);
8842 }
8843
8844 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8845                                u64 num_bytes, u64 *actual_bytes)
8846 {
8847         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8848 }
8849
8850 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8851 {
8852         struct btrfs_fs_info *fs_info = root->fs_info;
8853         struct btrfs_block_group_cache *cache = NULL;
8854         u64 group_trimmed;
8855         u64 start;
8856         u64 end;
8857         u64 trimmed = 0;
8858         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8859         int ret = 0;
8860
8861         /*
8862          * try to trim all FS space, our block group may start from non-zero.
8863          */
8864         if (range->len == total_bytes)
8865                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8866         else
8867                 cache = btrfs_lookup_block_group(fs_info, range->start);
8868
8869         while (cache) {
8870                 if (cache->key.objectid >= (range->start + range->len)) {
8871                         btrfs_put_block_group(cache);
8872                         break;
8873                 }
8874
8875                 start = max(range->start, cache->key.objectid);
8876                 end = min(range->start + range->len,
8877                                 cache->key.objectid + cache->key.offset);
8878
8879                 if (end - start >= range->minlen) {
8880                         if (!block_group_cache_done(cache)) {
8881                                 ret = cache_block_group(cache, 0);
8882                                 if (ret) {
8883                                         btrfs_put_block_group(cache);
8884                                         break;
8885                                 }
8886                                 ret = wait_block_group_cache_done(cache);
8887                                 if (ret) {
8888                                         btrfs_put_block_group(cache);
8889                                         break;
8890                                 }
8891                         }
8892                         ret = btrfs_trim_block_group(cache,
8893                                                      &group_trimmed,
8894                                                      start,
8895                                                      end,
8896                                                      range->minlen);
8897
8898                         trimmed += group_trimmed;
8899                         if (ret) {
8900                                 btrfs_put_block_group(cache);
8901                                 break;
8902                         }
8903                 }
8904
8905                 cache = next_block_group(fs_info->tree_root, cache);
8906         }
8907
8908         range->len = trimmed;
8909         return ret;
8910 }