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