fs/btrfs/extent-tree.c

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