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 "compat.h"
  27 #include "hash.h"
  28 #include "ctree.h"
  29 #include "disk-io.h"
  30 #include "print-tree.h"
  31 #include "transaction.h"
  32 #include "volumes.h"
  33 #include "locking.h"
  34 #include "free-space-cache.h"
  35
  36 /* control flags for do_chunk_alloc's force field
  37  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  38  * if we really need one.
  39  *
  40  * CHUNK_ALLOC_FORCE means it must try to allocate one
  41  *
  42  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  43  * if we have very few chunks already allocated.  This is
  44  * used as part of the clustering code to help make sure
  45  * we have a good pool of storage to cluster in, without
  46  * filling the FS with empty chunks
  47  *
  48  */
  49 enum {
  50         CHUNK_ALLOC_NO_FORCE = 0,
  51         CHUNK_ALLOC_FORCE = 1,
  52         CHUNK_ALLOC_LIMITED = 2,
  53 };
  54
  55 static int update_block_group(struct btrfs_trans_handle *trans,
  56                               struct btrfs_root *root,
  57                               u64 bytenr, u64 num_bytes, int alloc);
  58 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  59                                 struct btrfs_root *root,
  60                                 u64 bytenr, u64 num_bytes, u64 parent,
  61                                 u64 root_objectid, u64 owner_objectid,
  62                                 u64 owner_offset, int refs_to_drop,
  63                                 struct btrfs_delayed_extent_op *extra_op);
  64 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  65                                     struct extent_buffer *leaf,
  66                                     struct btrfs_extent_item *ei);
  67 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  68                                       struct btrfs_root *root,
  69                                       u64 parent, u64 root_objectid,
  70                                       u64 flags, u64 owner, u64 offset,
  71                                       struct btrfs_key *ins, int ref_mod);
  72 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  73                                      struct btrfs_root *root,
  74                                      u64 parent, u64 root_objectid,
  75                                      u64 flags, struct btrfs_disk_key *key,
  76                                      int level, struct btrfs_key *ins);
  77 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  78                           struct btrfs_root *extent_root, u64 alloc_bytes,
  79                           u64 flags, int force);
  80 static int find_next_key(struct btrfs_path *path, int level,
  81                          struct btrfs_key *key);
  82 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
  83                             int dump_block_groups);
  84
  85 static noinline int
  86 block_group_cache_done(struct btrfs_block_group_cache *cache)
  87 {
  88         smp_mb();
  89         return cache->cached == BTRFS_CACHE_FINISHED;
  90 }
  91
  92 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  93 {
  94         return (cache->flags & bits) == bits;
  95 }
  96
  97 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
  98 {
  99         atomic_inc(&cache->count);
 100 }
 101
 102 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 103 {
 104         if (atomic_dec_and_test(&cache->count)) {
 105                 WARN_ON(cache->pinned > 0);
 106                 WARN_ON(cache->reserved > 0);
 107                 WARN_ON(cache->reserved_pinned > 0);
 108                 kfree(cache->free_space_ctl);
 109                 kfree(cache);
 110         }
 111 }
 112
 113 /*
 114  * this adds the block group to the fs_info rb tree for the block group
 115  * cache
 116  */
 117 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 118                                 struct btrfs_block_group_cache *block_group)
 119 {
 120         struct rb_node **p;
 121         struct rb_node *parent = NULL;
 122         struct btrfs_block_group_cache *cache;
 123
 124         spin_lock(&info->block_group_cache_lock);
 125         p = &info->block_group_cache_tree.rb_node;
 126
 127         while (*p) {
 128                 parent = *p;
 129                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 130                                  cache_node);
 131                 if (block_group->key.objectid < cache->key.objectid) {
 132                         p = &(*p)->rb_left;
 133                 } else if (block_group->key.objectid > cache->key.objectid) {
 134                         p = &(*p)->rb_right;
 135                 } else {
 136                         spin_unlock(&info->block_group_cache_lock);
 137                         return -EEXIST;
 138                 }
 139         }
 140
 141         rb_link_node(&block_group->cache_node, parent, p);
 142         rb_insert_color(&block_group->cache_node,
 143                         &info->block_group_cache_tree);
 144         spin_unlock(&info->block_group_cache_lock);
 145
 146         return 0;
 147 }
 148
 149 /*
 150  * This will return the block group at or after bytenr if contains is 0, else
 151  * it will return the block group that contains the bytenr
 152  */
 153 static struct btrfs_block_group_cache *
 154 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 155                               int contains)
 156 {
 157         struct btrfs_block_group_cache *cache, *ret = NULL;
 158         struct rb_node *n;
 159         u64 end, start;
 160
 161         spin_lock(&info->block_group_cache_lock);
 162         n = info->block_group_cache_tree.rb_node;
 163
 164         while (n) {
 165                 cache = rb_entry(n, struct btrfs_block_group_cache,
 166                                  cache_node);
 167                 end = cache->key.objectid + cache->key.offset - 1;
 168                 start = cache->key.objectid;
 169
 170                 if (bytenr < start) {
 171                         if (!contains && (!ret || start < ret->key.objectid))
 172                                 ret = cache;
 173                         n = n->rb_left;
 174                 } else if (bytenr > start) {
 175                         if (contains && bytenr <= end) {
 176                                 ret = cache;
 177                                 break;
 178                         }
 179                         n = n->rb_right;
 180                 } else {
 181                         ret = cache;
 182                         break;
 183                 }
 184         }
 185         if (ret)
 186                 btrfs_get_block_group(ret);
 187         spin_unlock(&info->block_group_cache_lock);
 188
 189         return ret;
 190 }
 191
 192 static int add_excluded_extent(struct btrfs_root *root,
 193                                u64 start, u64 num_bytes)
 194 {
 195         u64 end = start + num_bytes - 1;
 196         set_extent_bits(&root->fs_info->freed_extents[0],
 197                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 198         set_extent_bits(&root->fs_info->freed_extents[1],
 199                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 200         return 0;
 201 }
 202
 203 static void free_excluded_extents(struct btrfs_root *root,
 204                                   struct btrfs_block_group_cache *cache)
 205 {
 206         u64 start, end;
 207
 208         start = cache->key.objectid;
 209         end = start + cache->key.offset - 1;
 210
 211         clear_extent_bits(&root->fs_info->freed_extents[0],
 212                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 213         clear_extent_bits(&root->fs_info->freed_extents[1],
 214                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 215 }
 216
 217 static int exclude_super_stripes(struct btrfs_root *root,
 218                                  struct btrfs_block_group_cache *cache)
 219 {
 220         u64 bytenr;
 221         u64 *logical;
 222         int stripe_len;
 223         int i, nr, ret;
 224
 225         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 226                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 227                 cache->bytes_super += stripe_len;
 228                 ret = add_excluded_extent(root, cache->key.objectid,
 229                                           stripe_len);
 230                 BUG_ON(ret);
 231         }
 232
 233         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 234                 bytenr = btrfs_sb_offset(i);
 235                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 236                                        cache->key.objectid, bytenr,
 237                                        0, &logical, &nr, &stripe_len);
 238                 BUG_ON(ret);
 239
 240                 while (nr--) {
 241                         cache->bytes_super += stripe_len;
 242                         ret = add_excluded_extent(root, logical[nr],
 243                                                   stripe_len);
 244                         BUG_ON(ret);
 245                 }
 246
 247                 kfree(logical);
 248         }
 249         return 0;
 250 }
 251
 252 static struct btrfs_caching_control *
 253 get_caching_control(struct btrfs_block_group_cache *cache)
 254 {
 255         struct btrfs_caching_control *ctl;
 256
 257         spin_lock(&cache->lock);
 258         if (cache->cached != BTRFS_CACHE_STARTED) {
 259                 spin_unlock(&cache->lock);
 260                 return NULL;
 261         }
 262
 263         /* We're loading it the fast way, so we don't have a caching_ctl. */
 264         if (!cache->caching_ctl) {
 265                 spin_unlock(&cache->lock);
 266                 return NULL;
 267         }
 268
 269         ctl = cache->caching_ctl;
 270         atomic_inc(&ctl->count);
 271         spin_unlock(&cache->lock);
 272         return ctl;
 273 }
 274
 275 static void put_caching_control(struct btrfs_caching_control *ctl)
 276 {
 277         if (atomic_dec_and_test(&ctl->count))
 278                 kfree(ctl);
 279 }
 280
 281 /*
 282  * this is only called by cache_block_group, since we could have freed extents
 283  * we need to check the pinned_extents for any extents that can't be used yet
 284  * since their free space will be released as soon as the transaction commits.
 285  */
 286 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 287                               struct btrfs_fs_info *info, u64 start, u64 end)
 288 {
 289         u64 extent_start, extent_end, size, total_added = 0;
 290         int ret;
 291
 292         while (start < end) {
 293                 ret = find_first_extent_bit(info->pinned_extents, start,
 294                                             &extent_start, &extent_end,
 295                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 296                 if (ret)
 297                         break;
 298
 299                 if (extent_start <= start) {
 300                         start = extent_end + 1;
 301                 } else if (extent_start > start && extent_start < end) {
 302                         size = extent_start - start;
 303                         total_added += size;
 304                         ret = btrfs_add_free_space(block_group, start,
 305                                                    size);
 306                         BUG_ON(ret);
 307                         start = extent_end + 1;
 308                 } else {
 309                         break;
 310                 }
 311         }
 312
 313         if (start < end) {
 314                 size = end - start;
 315                 total_added += size;
 316                 ret = btrfs_add_free_space(block_group, start, size);
 317                 BUG_ON(ret);
 318         }
 319
 320         return total_added;
 321 }
 322
 323 static noinline void caching_thread(struct btrfs_work *work)
 324 {
 325         struct btrfs_block_group_cache *block_group;
 326         struct btrfs_fs_info *fs_info;
 327         struct btrfs_caching_control *caching_ctl;
 328         struct btrfs_root *extent_root;
 329         struct btrfs_path *path;
 330         struct extent_buffer *leaf;
 331         struct btrfs_key key;
 332         u64 total_found = 0;
 333         u64 last = 0;
 334         u32 nritems;
 335         int ret = 0;
 336
 337         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 338         block_group = caching_ctl->block_group;
 339         fs_info = block_group->fs_info;
 340         extent_root = fs_info->extent_root;
 341
 342         path = btrfs_alloc_path();
 343         if (!path)
 344                 goto out;
 345
 346         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 347
 348         /*
 349          * We don't want to deadlock with somebody trying to allocate a new
 350          * extent for the extent root while also trying to search the extent
 351          * root to add free space.  So we skip locking and search the commit
 352          * root, since its read-only
 353          */
 354         path->skip_locking = 1;
 355         path->search_commit_root = 1;
 356         path->reada = 1;
 357
 358         key.objectid = last;
 359         key.offset = 0;
 360         key.type = BTRFS_EXTENT_ITEM_KEY;
 361 again:
 362         mutex_lock(&caching_ctl->mutex);
 363         /* need to make sure the commit_root doesn't disappear */
 364         down_read(&fs_info->extent_commit_sem);
 365
 366         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 367         if (ret < 0)
 368                 goto err;
 369
 370         leaf = path->nodes[0];
 371         nritems = btrfs_header_nritems(leaf);
 372
 373         while (1) {
 374                 if (btrfs_fs_closing(fs_info) > 1) {
 375                         last = (u64)-1;
 376                         break;
 377                 }
 378
 379                 if (path->slots[0] < nritems) {
 380                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 381                 } else {
 382                         ret = find_next_key(path, 0, &key);
 383                         if (ret)
 384                                 break;
 385
 386                         if (need_resched() ||
 387                             btrfs_next_leaf(extent_root, path)) {
 388                                 caching_ctl->progress = last;
 389                                 btrfs_release_path(path);
 390                                 up_read(&fs_info->extent_commit_sem);
 391                                 mutex_unlock(&caching_ctl->mutex);
 392                                 cond_resched();
 393                                 goto again;
 394                         }
 395                         leaf = path->nodes[0];
 396                         nritems = btrfs_header_nritems(leaf);
 397                         continue;
 398                 }
 399
 400                 if (key.objectid < block_group->key.objectid) {
 401                         path->slots[0]++;
 402                         continue;
 403                 }
 404
 405                 if (key.objectid >= block_group->key.objectid +
 406                     block_group->key.offset)
 407                         break;
 408
 409                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 410                         total_found += add_new_free_space(block_group,
 411                                                           fs_info, last,
 412                                                           key.objectid);
 413                         last = key.objectid + key.offset;
 414
 415                         if (total_found > (1024 * 1024 * 2)) {
 416                                 total_found = 0;
 417                                 wake_up(&caching_ctl->wait);
 418                         }
 419                 }
 420                 path->slots[0]++;
 421         }
 422         ret = 0;
 423
 424         total_found += add_new_free_space(block_group, fs_info, last,
 425                                           block_group->key.objectid +
 426                                           block_group->key.offset);
 427         caching_ctl->progress = (u64)-1;
 428
 429         spin_lock(&block_group->lock);
 430         block_group->caching_ctl = NULL;
 431         block_group->cached = BTRFS_CACHE_FINISHED;
 432         spin_unlock(&block_group->lock);
 433
 434 err:
 435         btrfs_free_path(path);
 436         up_read(&fs_info->extent_commit_sem);
 437
 438         free_excluded_extents(extent_root, block_group);
 439
 440         mutex_unlock(&caching_ctl->mutex);
 441 out:
 442         wake_up(&caching_ctl->wait);
 443
 444         put_caching_control(caching_ctl);
 445         btrfs_put_block_group(block_group);
 446 }
 447
 448 static int cache_block_group(struct btrfs_block_group_cache *cache,
 449                              struct btrfs_trans_handle *trans,
 450                              struct btrfs_root *root,
 451                              int load_cache_only)
 452 {
 453         struct btrfs_fs_info *fs_info = cache->fs_info;
 454         struct btrfs_caching_control *caching_ctl;
 455         int ret = 0;
 456
 457         smp_mb();
 458         if (cache->cached != BTRFS_CACHE_NO)
 459                 return 0;
 460
 461         /*
 462          * We can't do the read from on-disk cache during a commit since we need
 463          * to have the normal tree locking.  Also if we are currently trying to
 464          * allocate blocks for the tree root we can't do the fast caching since
 465          * we likely hold important locks.
 466          */
 467         if (trans && (!trans->transaction->in_commit) &&
 468             (root && root != root->fs_info->tree_root)) {
 469                 spin_lock(&cache->lock);
 470                 if (cache->cached != BTRFS_CACHE_NO) {
 471                         spin_unlock(&cache->lock);
 472                         return 0;
 473                 }
 474                 cache->cached = BTRFS_CACHE_STARTED;
 475                 spin_unlock(&cache->lock);
 476
 477                 ret = load_free_space_cache(fs_info, cache);
 478
 479                 spin_lock(&cache->lock);
 480                 if (ret == 1) {
 481                         cache->cached = BTRFS_CACHE_FINISHED;
 482                         cache->last_byte_to_unpin = (u64)-1;
 483                 } else {
 484                         cache->cached = BTRFS_CACHE_NO;
 485                 }
 486                 spin_unlock(&cache->lock);
 487                 if (ret == 1) {
 488                         free_excluded_extents(fs_info->extent_root, cache);
 489                         return 0;
 490                 }
 491         }
 492
 493         if (load_cache_only)
 494                 return 0;
 495
 496         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 497         BUG_ON(!caching_ctl);
 498
 499         INIT_LIST_HEAD(&caching_ctl->list);
 500         mutex_init(&caching_ctl->mutex);
 501         init_waitqueue_head(&caching_ctl->wait);
 502         caching_ctl->block_group = cache;
 503         caching_ctl->progress = cache->key.objectid;
 504         /* one for caching kthread, one for caching block group list */
 505         atomic_set(&caching_ctl->count, 2);
 506         caching_ctl->work.func = caching_thread;
 507
 508         spin_lock(&cache->lock);
 509         if (cache->cached != BTRFS_CACHE_NO) {
 510                 spin_unlock(&cache->lock);
 511                 kfree(caching_ctl);
 512                 return 0;
 513         }
 514         cache->caching_ctl = caching_ctl;
 515         cache->cached = BTRFS_CACHE_STARTED;
 516         spin_unlock(&cache->lock);
 517
 518         down_write(&fs_info->extent_commit_sem);
 519         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 520         up_write(&fs_info->extent_commit_sem);
 521
 522         btrfs_get_block_group(cache);
 523
 524         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 525
 526         return ret;
 527 }
 528
 529 /*
 530  * return the block group that starts at or after bytenr
 531  */
 532 static struct btrfs_block_group_cache *
 533 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 534 {
 535         struct btrfs_block_group_cache *cache;
 536
 537         cache = block_group_cache_tree_search(info, bytenr, 0);
 538
 539         return cache;
 540 }
 541
 542 /*
 543  * return the block group that contains the given bytenr
 544  */
 545 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 546                                                  struct btrfs_fs_info *info,
 547                                                  u64 bytenr)
 548 {
 549         struct btrfs_block_group_cache *cache;
 550
 551         cache = block_group_cache_tree_search(info, bytenr, 1);
 552
 553         return cache;
 554 }
 555
 556 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 557                                                   u64 flags)
 558 {
 559         struct list_head *head = &info->space_info;
 560         struct btrfs_space_info *found;
 561
 562         flags &= BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_SYSTEM |
 563                  BTRFS_BLOCK_GROUP_METADATA;
 564
 565         rcu_read_lock();
 566         list_for_each_entry_rcu(found, head, list) {
 567                 if (found->flags & flags) {
 568                         rcu_read_unlock();
 569                         return found;
 570                 }
 571         }
 572         rcu_read_unlock();
 573         return NULL;
 574 }
 575
 576 /*
 577  * after adding space to the filesystem, we need to clear the full flags
 578  * on all the space infos.
 579  */
 580 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 581 {
 582         struct list_head *head = &info->space_info;
 583         struct btrfs_space_info *found;
 584
 585         rcu_read_lock();
 586         list_for_each_entry_rcu(found, head, list)
 587                 found->full = 0;
 588         rcu_read_unlock();
 589 }
 590
 591 static u64 div_factor(u64 num, int factor)
 592 {
 593         if (factor == 10)
 594                 return num;
 595         num *= factor;
 596         do_div(num, 10);
 597         return num;
 598 }
 599
 600 static u64 div_factor_fine(u64 num, int factor)
 601 {
 602         if (factor == 100)
 603                 return num;
 604         num *= factor;
 605         do_div(num, 100);
 606         return num;
 607 }
 608
 609 u64 btrfs_find_block_group(struct btrfs_root *root,
 610                            u64 search_start, u64 search_hint, int owner)
 611 {
 612         struct btrfs_block_group_cache *cache;
 613         u64 used;
 614         u64 last = max(search_hint, search_start);
 615         u64 group_start = 0;
 616         int full_search = 0;
 617         int factor = 9;
 618         int wrapped = 0;
 619 again:
 620         while (1) {
 621                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 622                 if (!cache)
 623                         break;
 624
 625                 spin_lock(&cache->lock);
 626                 last = cache->key.objectid + cache->key.offset;
 627                 used = btrfs_block_group_used(&cache->item);
 628
 629                 if ((full_search || !cache->ro) &&
 630                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 631                         if (used + cache->pinned + cache->reserved <
 632                             div_factor(cache->key.offset, factor)) {
 633                                 group_start = cache->key.objectid;
 634                                 spin_unlock(&cache->lock);
 635                                 btrfs_put_block_group(cache);
 636                                 goto found;
 637                         }
 638                 }
 639                 spin_unlock(&cache->lock);
 640                 btrfs_put_block_group(cache);
 641                 cond_resched();
 642         }
 643         if (!wrapped) {
 644                 last = search_start;
 645                 wrapped = 1;
 646                 goto again;
 647         }
 648         if (!full_search && factor < 10) {
 649                 last = search_start;
 650                 full_search = 1;
 651                 factor = 10;
 652                 goto again;
 653         }
 654 found:
 655         return group_start;
 656 }
 657
 658 /* simple helper to search for an existing extent at a given offset */
 659 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 660 {
 661         int ret;
 662         struct btrfs_key key;
 663         struct btrfs_path *path;
 664
 665         path = btrfs_alloc_path();
 666         if (!path)
 667                 return -ENOMEM;
 668
 669         key.objectid = start;
 670         key.offset = len;
 671         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 672         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 673                                 0, 0);
 674         btrfs_free_path(path);
 675         return ret;
 676 }
 677
 678 /*
 679  * helper function to lookup reference count and flags of extent.
 680  *
 681  * the head node for delayed ref is used to store the sum of all the
 682  * reference count modifications queued up in the rbtree. the head
 683  * node may also store the extent flags to set. This way you can check
 684  * to see what the reference count and extent flags would be if all of
 685  * the delayed refs are not processed.
 686  */
 687 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 688                              struct btrfs_root *root, u64 bytenr,
 689                              u64 num_bytes, u64 *refs, u64 *flags)
 690 {
 691         struct btrfs_delayed_ref_head *head;
 692         struct btrfs_delayed_ref_root *delayed_refs;
 693         struct btrfs_path *path;
 694         struct btrfs_extent_item *ei;
 695         struct extent_buffer *leaf;
 696         struct btrfs_key key;
 697         u32 item_size;
 698         u64 num_refs;
 699         u64 extent_flags;
 700         int ret;
 701
 702         path = btrfs_alloc_path();
 703         if (!path)
 704                 return -ENOMEM;
 705
 706         key.objectid = bytenr;
 707         key.type = BTRFS_EXTENT_ITEM_KEY;
 708         key.offset = num_bytes;
 709         if (!trans) {
 710                 path->skip_locking = 1;
 711                 path->search_commit_root = 1;
 712         }
 713 again:
 714         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 715                                 &key, path, 0, 0);
 716         if (ret < 0)
 717                 goto out_free;
 718
 719         if (ret == 0) {
 720                 leaf = path->nodes[0];
 721                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 722                 if (item_size >= sizeof(*ei)) {
 723                         ei = btrfs_item_ptr(leaf, path->slots[0],
 724                                             struct btrfs_extent_item);
 725                         num_refs = btrfs_extent_refs(leaf, ei);
 726                         extent_flags = btrfs_extent_flags(leaf, ei);
 727                 } else {
 728 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 729                         struct btrfs_extent_item_v0 *ei0;
 730                         BUG_ON(item_size != sizeof(*ei0));
 731                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 732                                              struct btrfs_extent_item_v0);
 733                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 734                         /* FIXME: this isn't correct for data */
 735                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 736 #else
 737                         BUG();
 738 #endif
 739                 }
 740                 BUG_ON(num_refs == 0);
 741         } else {
 742                 num_refs = 0;
 743                 extent_flags = 0;
 744                 ret = 0;
 745         }
 746
 747         if (!trans)
 748                 goto out;
 749
 750         delayed_refs = &trans->transaction->delayed_refs;
 751         spin_lock(&delayed_refs->lock);
 752         head = btrfs_find_delayed_ref_head(trans, bytenr);
 753         if (head) {
 754                 if (!mutex_trylock(&head->mutex)) {
 755                         atomic_inc(&head->node.refs);
 756                         spin_unlock(&delayed_refs->lock);
 757
 758                         btrfs_release_path(path);
 759
 760                         /*
 761                          * Mutex was contended, block until it's released and try
 762                          * again
 763                          */
 764                         mutex_lock(&head->mutex);
 765                         mutex_unlock(&head->mutex);
 766                         btrfs_put_delayed_ref(&head->node);
 767                         goto again;
 768                 }
 769                 if (head->extent_op && head->extent_op->update_flags)
 770                         extent_flags |= head->extent_op->flags_to_set;
 771                 else
 772                         BUG_ON(num_refs == 0);
 773
 774                 num_refs += head->node.ref_mod;
 775                 mutex_unlock(&head->mutex);
 776         }
 777         spin_unlock(&delayed_refs->lock);
 778 out:
 779         WARN_ON(num_refs == 0);
 780         if (refs)
 781                 *refs = num_refs;
 782         if (flags)
 783                 *flags = extent_flags;
 784 out_free:
 785         btrfs_free_path(path);
 786         return ret;
 787 }
 788
 789 /*
 790  * Back reference rules.  Back refs have three main goals:
 791  *
 792  * 1) differentiate between all holders of references to an extent so that
 793  *    when a reference is dropped we can make sure it was a valid reference
 794  *    before freeing the extent.
 795  *
 796  * 2) Provide enough information to quickly find the holders of an extent
 797  *    if we notice a given block is corrupted or bad.
 798  *
 799  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 800  *    maintenance.  This is actually the same as #2, but with a slightly
 801  *    different use case.
 802  *
 803  * There are two kinds of back refs. The implicit back refs is optimized
 804  * for pointers in non-shared tree blocks. For a given pointer in a block,
 805  * back refs of this kind provide information about the block's owner tree
 806  * and the pointer's key. These information allow us to find the block by
 807  * b-tree searching. The full back refs is for pointers in tree blocks not
 808  * referenced by their owner trees. The location of tree block is recorded
 809  * in the back refs. Actually the full back refs is generic, and can be
 810  * used in all cases the implicit back refs is used. The major shortcoming
 811  * of the full back refs is its overhead. Every time a tree block gets
 812  * COWed, we have to update back refs entry for all pointers in it.
 813  *
 814  * For a newly allocated tree block, we use implicit back refs for
 815  * pointers in it. This means most tree related operations only involve
 816  * implicit back refs. For a tree block created in old transaction, the
 817  * only way to drop a reference to it is COW it. So we can detect the
 818  * event that tree block loses its owner tree's reference and do the
 819  * back refs conversion.
 820  *
 821  * When a tree block is COW'd through a tree, there are four cases:
 822  *
 823  * The reference count of the block is one and the tree is the block's
 824  * owner tree. Nothing to do in this case.
 825  *
 826  * The reference count of the block is one and the tree is not the
 827  * block's owner tree. In this case, full back refs is used for pointers
 828  * in the block. Remove these full back refs, add implicit back refs for
 829  * every pointers in the new block.
 830  *
 831  * The reference count of the block is greater than one and the tree is
 832  * the block's owner tree. In this case, implicit back refs is used for
 833  * pointers in the block. Add full back refs for every pointers in the
 834  * block, increase lower level extents' reference counts. The original
 835  * implicit back refs are entailed to the new block.
 836  *
 837  * The reference count of the block is greater than one and the tree is
 838  * not the block's owner tree. Add implicit back refs for every pointer in
 839  * the new block, increase lower level extents' reference count.
 840  *
 841  * Back Reference Key composing:
 842  *
 843  * The key objectid corresponds to the first byte in the extent,
 844  * The key type is used to differentiate between types of back refs.
 845  * There are different meanings of the key offset for different types
 846  * of back refs.
 847  *
 848  * File extents can be referenced by:
 849  *
 850  * - multiple snapshots, subvolumes, or different generations in one subvol
 851  * - different files inside a single subvolume
 852  * - different offsets inside a file (bookend extents in file.c)
 853  *
 854  * The extent ref structure for the implicit back refs has fields for:
 855  *
 856  * - Objectid of the subvolume root
 857  * - objectid of the file holding the reference
 858  * - original offset in the file
 859  * - how many bookend extents
 860  *
 861  * The key offset for the implicit back refs is hash of the first
 862  * three fields.
 863  *
 864  * The extent ref structure for the full back refs has field for:
 865  *
 866  * - number of pointers in the tree leaf
 867  *
 868  * The key offset for the implicit back refs is the first byte of
 869  * the tree leaf
 870  *
 871  * When a file extent is allocated, The implicit back refs is used.
 872  * the fields are filled in:
 873  *
 874  *     (root_key.objectid, inode objectid, offset in file, 1)
 875  *
 876  * When a file extent is removed file truncation, we find the
 877  * corresponding implicit back refs and check the following fields:
 878  *
 879  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 880  *
 881  * Btree extents can be referenced by:
 882  *
 883  * - Different subvolumes
 884  *
 885  * Both the implicit back refs and the full back refs for tree blocks
 886  * only consist of key. The key offset for the implicit back refs is
 887  * objectid of block's owner tree. The key offset for the full back refs
 888  * is the first byte of parent block.
 889  *
 890  * When implicit back refs is used, information about the lowest key and
 891  * level of the tree block are required. These information are stored in
 892  * tree block info structure.
 893  */
 894
 895 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 896 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 897                                   struct btrfs_root *root,
 898                                   struct btrfs_path *path,
 899                                   u64 owner, u32 extra_size)
 900 {
 901         struct btrfs_extent_item *item;
 902         struct btrfs_extent_item_v0 *ei0;
 903         struct btrfs_extent_ref_v0 *ref0;
 904         struct btrfs_tree_block_info *bi;
 905         struct extent_buffer *leaf;
 906         struct btrfs_key key;
 907         struct btrfs_key found_key;
 908         u32 new_size = sizeof(*item);
 909         u64 refs;
 910         int ret;
 911
 912         leaf = path->nodes[0];
 913         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 914
 915         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 916         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 917                              struct btrfs_extent_item_v0);
 918         refs = btrfs_extent_refs_v0(leaf, ei0);
 919
 920         if (owner == (u64)-1) {
 921                 while (1) {
 922                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 923                                 ret = btrfs_next_leaf(root, path);
 924                                 if (ret < 0)
 925                                         return ret;
 926                                 BUG_ON(ret > 0);
 927                                 leaf = path->nodes[0];
 928                         }
 929                         btrfs_item_key_to_cpu(leaf, &found_key,
 930                                               path->slots[0]);
 931                         BUG_ON(key.objectid != found_key.objectid);
 932                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 933                                 path->slots[0]++;
 934                                 continue;
 935                         }
 936                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 937                                               struct btrfs_extent_ref_v0);
 938                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 939                         break;
 940                 }
 941         }
 942         btrfs_release_path(path);
 943
 944         if (owner < BTRFS_FIRST_FREE_OBJECTID)
 945                 new_size += sizeof(*bi);
 946
 947         new_size -= sizeof(*ei0);
 948         ret = btrfs_search_slot(trans, root, &key, path,
 949                                 new_size + extra_size, 1);
 950         if (ret < 0)
 951                 return ret;
 952         BUG_ON(ret);
 953
 954         ret = btrfs_extend_item(trans, root, path, new_size);
 955
 956         leaf = path->nodes[0];
 957         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 958         btrfs_set_extent_refs(leaf, item, refs);
 959         /* FIXME: get real generation */
 960         btrfs_set_extent_generation(leaf, item, 0);
 961         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 962                 btrfs_set_extent_flags(leaf, item,
 963                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
 964                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
 965                 bi = (struct btrfs_tree_block_info *)(item + 1);
 966                 /* FIXME: get first key of the block */
 967                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
 968                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
 969         } else {
 970                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
 971         }
 972         btrfs_mark_buffer_dirty(leaf);
 973         return 0;
 974 }
 975 #endif
 976
 977 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 978 {
 979         u32 high_crc = ~(u32)0;
 980         u32 low_crc = ~(u32)0;
 981         __le64 lenum;
 982
 983         lenum = cpu_to_le64(root_objectid);
 984         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
 985         lenum = cpu_to_le64(owner);
 986         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 987         lenum = cpu_to_le64(offset);
 988         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 989
 990         return ((u64)high_crc << 31) ^ (u64)low_crc;
 991 }
 992
 993 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 994                                      struct btrfs_extent_data_ref *ref)
 995 {
 996         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 997                                     btrfs_extent_data_ref_objectid(leaf, ref),
 998                                     btrfs_extent_data_ref_offset(leaf, ref));
 999 }
1000
1001 static int match_extent_data_ref(struct extent_buffer *leaf,
1002                                  struct btrfs_extent_data_ref *ref,
1003                                  u64 root_objectid, u64 owner, u64 offset)
1004 {
1005         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1006             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1007             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1008                 return 0;
1009         return 1;
1010 }
1011
1012 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1013                                            struct btrfs_root *root,
1014                                            struct btrfs_path *path,
1015                                            u64 bytenr, u64 parent,
1016                                            u64 root_objectid,
1017                                            u64 owner, u64 offset)
1018 {
1019         struct btrfs_key key;
1020         struct btrfs_extent_data_ref *ref;
1021         struct extent_buffer *leaf;
1022         u32 nritems;
1023         int ret;
1024         int recow;
1025         int err = -ENOENT;
1026
1027         key.objectid = bytenr;
1028         if (parent) {
1029                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1030                 key.offset = parent;
1031         } else {
1032                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1033                 key.offset = hash_extent_data_ref(root_objectid,
1034                                                   owner, offset);
1035         }
1036 again:
1037         recow = 0;
1038         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1039         if (ret < 0) {
1040                 err = ret;
1041                 goto fail;
1042         }
1043
1044         if (parent) {
1045                 if (!ret)
1046                         return 0;
1047 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1048                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1049                 btrfs_release_path(path);
1050                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1051                 if (ret < 0) {
1052                         err = ret;
1053                         goto fail;
1054                 }
1055                 if (!ret)
1056                         return 0;
1057 #endif
1058                 goto fail;
1059         }
1060
1061         leaf = path->nodes[0];
1062         nritems = btrfs_header_nritems(leaf);
1063         while (1) {
1064                 if (path->slots[0] >= nritems) {
1065                         ret = btrfs_next_leaf(root, path);
1066                         if (ret < 0)
1067                                 err = ret;
1068                         if (ret)
1069                                 goto fail;
1070
1071                         leaf = path->nodes[0];
1072                         nritems = btrfs_header_nritems(leaf);
1073                         recow = 1;
1074                 }
1075
1076                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1077                 if (key.objectid != bytenr ||
1078                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1079                         goto fail;
1080
1081                 ref = btrfs_item_ptr(leaf, path->slots[0],
1082                                      struct btrfs_extent_data_ref);
1083
1084                 if (match_extent_data_ref(leaf, ref, root_objectid,
1085                                           owner, offset)) {
1086                         if (recow) {
1087                                 btrfs_release_path(path);
1088                                 goto again;
1089                         }
1090                         err = 0;
1091                         break;
1092                 }
1093                 path->slots[0]++;
1094         }
1095 fail:
1096         return err;
1097 }
1098
1099 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1100                                            struct btrfs_root *root,
1101                                            struct btrfs_path *path,
1102                                            u64 bytenr, u64 parent,
1103                                            u64 root_objectid, u64 owner,
1104                                            u64 offset, int refs_to_add)
1105 {
1106         struct btrfs_key key;
1107         struct extent_buffer *leaf;
1108         u32 size;
1109         u32 num_refs;
1110         int ret;
1111
1112         key.objectid = bytenr;
1113         if (parent) {
1114                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1115                 key.offset = parent;
1116                 size = sizeof(struct btrfs_shared_data_ref);
1117         } else {
1118                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1119                 key.offset = hash_extent_data_ref(root_objectid,
1120                                                   owner, offset);
1121                 size = sizeof(struct btrfs_extent_data_ref);
1122         }
1123
1124         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1125         if (ret && ret != -EEXIST)
1126                 goto fail;
1127
1128         leaf = path->nodes[0];
1129         if (parent) {
1130                 struct btrfs_shared_data_ref *ref;
1131                 ref = btrfs_item_ptr(leaf, path->slots[0],
1132                                      struct btrfs_shared_data_ref);
1133                 if (ret == 0) {
1134                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1135                 } else {
1136                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1137                         num_refs += refs_to_add;
1138                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1139                 }
1140         } else {
1141                 struct btrfs_extent_data_ref *ref;
1142                 while (ret == -EEXIST) {
1143                         ref = btrfs_item_ptr(leaf, path->slots[0],
1144                                              struct btrfs_extent_data_ref);
1145                         if (match_extent_data_ref(leaf, ref, root_objectid,
1146                                                   owner, offset))
1147                                 break;
1148                         btrfs_release_path(path);
1149                         key.offset++;
1150                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1151                                                       size);
1152                         if (ret && ret != -EEXIST)
1153                                 goto fail;
1154
1155                         leaf = path->nodes[0];
1156                 }
1157                 ref = btrfs_item_ptr(leaf, path->slots[0],
1158                                      struct btrfs_extent_data_ref);
1159                 if (ret == 0) {
1160                         btrfs_set_extent_data_ref_root(leaf, ref,
1161                                                        root_objectid);
1162                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1163                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1164                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1165                 } else {
1166                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1167                         num_refs += refs_to_add;
1168                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1169                 }
1170         }
1171         btrfs_mark_buffer_dirty(leaf);
1172         ret = 0;
1173 fail:
1174         btrfs_release_path(path);
1175         return ret;
1176 }
1177
1178 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1179                                            struct btrfs_root *root,
1180                                            struct btrfs_path *path,
1181                                            int refs_to_drop)
1182 {
1183         struct btrfs_key key;
1184         struct btrfs_extent_data_ref *ref1 = NULL;
1185         struct btrfs_shared_data_ref *ref2 = NULL;
1186         struct extent_buffer *leaf;
1187         u32 num_refs = 0;
1188         int ret = 0;
1189
1190         leaf = path->nodes[0];
1191         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1192
1193         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1194                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1195                                       struct btrfs_extent_data_ref);
1196                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1197         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1198                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1199                                       struct btrfs_shared_data_ref);
1200                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1201 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1202         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1203                 struct btrfs_extent_ref_v0 *ref0;
1204                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1205                                       struct btrfs_extent_ref_v0);
1206                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1207 #endif
1208         } else {
1209                 BUG();
1210         }
1211
1212         BUG_ON(num_refs < refs_to_drop);
1213         num_refs -= refs_to_drop;
1214
1215         if (num_refs == 0) {
1216                 ret = btrfs_del_item(trans, root, path);
1217         } else {
1218                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1219                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1220                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1221                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1222 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1223                 else {
1224                         struct btrfs_extent_ref_v0 *ref0;
1225                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1226                                         struct btrfs_extent_ref_v0);
1227                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1228                 }
1229 #endif
1230                 btrfs_mark_buffer_dirty(leaf);
1231         }
1232         return ret;
1233 }
1234
1235 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1236                                           struct btrfs_path *path,
1237                                           struct btrfs_extent_inline_ref *iref)
1238 {
1239         struct btrfs_key key;
1240         struct extent_buffer *leaf;
1241         struct btrfs_extent_data_ref *ref1;
1242         struct btrfs_shared_data_ref *ref2;
1243         u32 num_refs = 0;
1244
1245         leaf = path->nodes[0];
1246         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1247         if (iref) {
1248                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1249                     BTRFS_EXTENT_DATA_REF_KEY) {
1250                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1251                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1252                 } else {
1253                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1254                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1255                 }
1256         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1257                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1258                                       struct btrfs_extent_data_ref);
1259                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1260         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1261                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1262                                       struct btrfs_shared_data_ref);
1263                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1264 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1265         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1266                 struct btrfs_extent_ref_v0 *ref0;
1267                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1268                                       struct btrfs_extent_ref_v0);
1269                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1270 #endif
1271         } else {
1272                 WARN_ON(1);
1273         }
1274         return num_refs;
1275 }
1276
1277 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1278                                           struct btrfs_root *root,
1279                                           struct btrfs_path *path,
1280                                           u64 bytenr, u64 parent,
1281                                           u64 root_objectid)
1282 {
1283         struct btrfs_key key;
1284         int ret;
1285
1286         key.objectid = bytenr;
1287         if (parent) {
1288                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1289                 key.offset = parent;
1290         } else {
1291                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1292                 key.offset = root_objectid;
1293         }
1294
1295         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1296         if (ret > 0)
1297                 ret = -ENOENT;
1298 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1299         if (ret == -ENOENT && parent) {
1300                 btrfs_release_path(path);
1301                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1302                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1303                 if (ret > 0)
1304                         ret = -ENOENT;
1305         }
1306 #endif
1307         return ret;
1308 }
1309
1310 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1311                                           struct btrfs_root *root,
1312                                           struct btrfs_path *path,
1313                                           u64 bytenr, u64 parent,
1314                                           u64 root_objectid)
1315 {
1316         struct btrfs_key key;
1317         int ret;
1318
1319         key.objectid = bytenr;
1320         if (parent) {
1321                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1322                 key.offset = parent;
1323         } else {
1324                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1325                 key.offset = root_objectid;
1326         }
1327
1328         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1329         btrfs_release_path(path);
1330         return ret;
1331 }
1332
1333 static inline int extent_ref_type(u64 parent, u64 owner)
1334 {
1335         int type;
1336         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1337                 if (parent > 0)
1338                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1339                 else
1340                         type = BTRFS_TREE_BLOCK_REF_KEY;
1341         } else {
1342                 if (parent > 0)
1343                         type = BTRFS_SHARED_DATA_REF_KEY;
1344                 else
1345                         type = BTRFS_EXTENT_DATA_REF_KEY;
1346         }
1347         return type;
1348 }
1349
1350 static int find_next_key(struct btrfs_path *path, int level,
1351                          struct btrfs_key *key)
1352
1353 {
1354         for (; level < BTRFS_MAX_LEVEL; level++) {
1355                 if (!path->nodes[level])
1356                         break;
1357                 if (path->slots[level] + 1 >=
1358                     btrfs_header_nritems(path->nodes[level]))
1359                         continue;
1360                 if (level == 0)
1361                         btrfs_item_key_to_cpu(path->nodes[level], key,
1362                                               path->slots[level] + 1);
1363                 else
1364                         btrfs_node_key_to_cpu(path->nodes[level], key,
1365                                               path->slots[level] + 1);
1366                 return 0;
1367         }
1368         return 1;
1369 }
1370
1371 /*
1372  * look for inline back ref. if back ref is found, *ref_ret is set
1373  * to the address of inline back ref, and 0 is returned.
1374  *
1375  * if back ref isn't found, *ref_ret is set to the address where it
1376  * should be inserted, and -ENOENT is returned.
1377  *
1378  * if insert is true and there are too many inline back refs, the path
1379  * points to the extent item, and -EAGAIN is returned.
1380  *
1381  * NOTE: inline back refs are ordered in the same way that back ref
1382  *       items in the tree are ordered.
1383  */
1384 static noinline_for_stack
1385 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1386                                  struct btrfs_root *root,
1387                                  struct btrfs_path *path,
1388                                  struct btrfs_extent_inline_ref **ref_ret,
1389                                  u64 bytenr, u64 num_bytes,
1390                                  u64 parent, u64 root_objectid,
1391                                  u64 owner, u64 offset, int insert)
1392 {
1393         struct btrfs_key key;
1394         struct extent_buffer *leaf;
1395         struct btrfs_extent_item *ei;
1396         struct btrfs_extent_inline_ref *iref;
1397         u64 flags;
1398         u64 item_size;
1399         unsigned long ptr;
1400         unsigned long end;
1401         int extra_size;
1402         int type;
1403         int want;
1404         int ret;
1405         int err = 0;
1406
1407         key.objectid = bytenr;
1408         key.type = BTRFS_EXTENT_ITEM_KEY;
1409         key.offset = num_bytes;
1410
1411         want = extent_ref_type(parent, owner);
1412         if (insert) {
1413                 extra_size = btrfs_extent_inline_ref_size(want);
1414                 path->keep_locks = 1;
1415         } else
1416                 extra_size = -1;
1417         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1418         if (ret < 0) {
1419                 err = ret;
1420                 goto out;
1421         }
1422         BUG_ON(ret);
1423
1424         leaf = path->nodes[0];
1425         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1426 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1427         if (item_size < sizeof(*ei)) {
1428                 if (!insert) {
1429                         err = -ENOENT;
1430                         goto out;
1431                 }
1432                 ret = convert_extent_item_v0(trans, root, path, owner,
1433                                              extra_size);
1434                 if (ret < 0) {
1435                         err = ret;
1436                         goto out;
1437                 }
1438                 leaf = path->nodes[0];
1439                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1440         }
1441 #endif
1442         BUG_ON(item_size < sizeof(*ei));
1443
1444         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1445         flags = btrfs_extent_flags(leaf, ei);
1446
1447         ptr = (unsigned long)(ei + 1);
1448         end = (unsigned long)ei + item_size;
1449
1450         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1451                 ptr += sizeof(struct btrfs_tree_block_info);
1452                 BUG_ON(ptr > end);
1453         } else {
1454                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1455         }
1456
1457         err = -ENOENT;
1458         while (1) {
1459                 if (ptr >= end) {
1460                         WARN_ON(ptr > end);
1461                         break;
1462                 }
1463                 iref = (struct btrfs_extent_inline_ref *)ptr;
1464                 type = btrfs_extent_inline_ref_type(leaf, iref);
1465                 if (want < type)
1466                         break;
1467                 if (want > type) {
1468                         ptr += btrfs_extent_inline_ref_size(type);
1469                         continue;
1470                 }
1471
1472                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1473                         struct btrfs_extent_data_ref *dref;
1474                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1475                         if (match_extent_data_ref(leaf, dref, root_objectid,
1476                                                   owner, offset)) {
1477                                 err = 0;
1478                                 break;
1479                         }
1480                         if (hash_extent_data_ref_item(leaf, dref) <
1481                             hash_extent_data_ref(root_objectid, owner, offset))
1482                                 break;
1483                 } else {
1484                         u64 ref_offset;
1485                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1486                         if (parent > 0) {
1487                                 if (parent == ref_offset) {
1488                                         err = 0;
1489                                         break;
1490                                 }
1491                                 if (ref_offset < parent)
1492                                         break;
1493                         } else {
1494                                 if (root_objectid == ref_offset) {
1495                                         err = 0;
1496                                         break;
1497                                 }
1498                                 if (ref_offset < root_objectid)
1499                                         break;
1500                         }
1501                 }
1502                 ptr += btrfs_extent_inline_ref_size(type);
1503         }
1504         if (err == -ENOENT && insert) {
1505                 if (item_size + extra_size >=
1506                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1507                         err = -EAGAIN;
1508                         goto out;
1509                 }
1510                 /*
1511                  * To add new inline back ref, we have to make sure
1512                  * there is no corresponding back ref item.
1513                  * For simplicity, we just do not add new inline back
1514                  * ref if there is any kind of item for this block
1515                  */
1516                 if (find_next_key(path, 0, &key) == 0 &&
1517                     key.objectid == bytenr &&
1518                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1519                         err = -EAGAIN;
1520                         goto out;
1521                 }
1522         }
1523         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1524 out:
1525         if (insert) {
1526                 path->keep_locks = 0;
1527                 btrfs_unlock_up_safe(path, 1);
1528         }
1529         return err;
1530 }
1531
1532 /*
1533  * helper to add new inline back ref
1534  */
1535 static noinline_for_stack
1536 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1537                                 struct btrfs_root *root,
1538                                 struct btrfs_path *path,
1539                                 struct btrfs_extent_inline_ref *iref,
1540                                 u64 parent, u64 root_objectid,
1541                                 u64 owner, u64 offset, int refs_to_add,
1542                                 struct btrfs_delayed_extent_op *extent_op)
1543 {
1544         struct extent_buffer *leaf;
1545         struct btrfs_extent_item *ei;
1546         unsigned long ptr;
1547         unsigned long end;
1548         unsigned long item_offset;
1549         u64 refs;
1550         int size;
1551         int type;
1552         int ret;
1553
1554         leaf = path->nodes[0];
1555         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1556         item_offset = (unsigned long)iref - (unsigned long)ei;
1557
1558         type = extent_ref_type(parent, owner);
1559         size = btrfs_extent_inline_ref_size(type);
1560
1561         ret = btrfs_extend_item(trans, root, path, size);
1562
1563         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1564         refs = btrfs_extent_refs(leaf, ei);
1565         refs += refs_to_add;
1566         btrfs_set_extent_refs(leaf, ei, refs);
1567         if (extent_op)
1568                 __run_delayed_extent_op(extent_op, leaf, ei);
1569
1570         ptr = (unsigned long)ei + item_offset;
1571         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1572         if (ptr < end - size)
1573                 memmove_extent_buffer(leaf, ptr + size, ptr,
1574                                       end - size - ptr);
1575
1576         iref = (struct btrfs_extent_inline_ref *)ptr;
1577         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1578         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1579                 struct btrfs_extent_data_ref *dref;
1580                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1581                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1582                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1583                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1584                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1585         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1586                 struct btrfs_shared_data_ref *sref;
1587                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1588                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1589                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1590         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1591                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1592         } else {
1593                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1594         }
1595         btrfs_mark_buffer_dirty(leaf);
1596         return 0;
1597 }
1598
1599 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1600                                  struct btrfs_root *root,
1601                                  struct btrfs_path *path,
1602                                  struct btrfs_extent_inline_ref **ref_ret,
1603                                  u64 bytenr, u64 num_bytes, u64 parent,
1604                                  u64 root_objectid, u64 owner, u64 offset)
1605 {
1606         int ret;
1607
1608         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1609                                            bytenr, num_bytes, parent,
1610                                            root_objectid, owner, offset, 0);
1611         if (ret != -ENOENT)
1612                 return ret;
1613
1614         btrfs_release_path(path);
1615         *ref_ret = NULL;
1616
1617         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1618                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1619                                             root_objectid);
1620         } else {
1621                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1622                                              root_objectid, owner, offset);
1623         }
1624         return ret;
1625 }
1626
1627 /*
1628  * helper to update/remove inline back ref
1629  */
1630 static noinline_for_stack
1631 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1632                                  struct btrfs_root *root,
1633                                  struct btrfs_path *path,
1634                                  struct btrfs_extent_inline_ref *iref,
1635                                  int refs_to_mod,
1636                                  struct btrfs_delayed_extent_op *extent_op)
1637 {
1638         struct extent_buffer *leaf;
1639         struct btrfs_extent_item *ei;
1640         struct btrfs_extent_data_ref *dref = NULL;
1641         struct btrfs_shared_data_ref *sref = NULL;
1642         unsigned long ptr;
1643         unsigned long end;
1644         u32 item_size;
1645         int size;
1646         int type;
1647         int ret;
1648         u64 refs;
1649
1650         leaf = path->nodes[0];
1651         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1652         refs = btrfs_extent_refs(leaf, ei);
1653         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1654         refs += refs_to_mod;
1655         btrfs_set_extent_refs(leaf, ei, refs);
1656         if (extent_op)
1657                 __run_delayed_extent_op(extent_op, leaf, ei);
1658
1659         type = btrfs_extent_inline_ref_type(leaf, iref);
1660
1661         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1662                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1663                 refs = btrfs_extent_data_ref_count(leaf, dref);
1664         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1665                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1666                 refs = btrfs_shared_data_ref_count(leaf, sref);
1667         } else {
1668                 refs = 1;
1669                 BUG_ON(refs_to_mod != -1);
1670         }
1671
1672         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1673         refs += refs_to_mod;
1674
1675         if (refs > 0) {
1676                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1677                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1678                 else
1679                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1680         } else {
1681                 size =  btrfs_extent_inline_ref_size(type);
1682                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1683                 ptr = (unsigned long)iref;
1684                 end = (unsigned long)ei + item_size;
1685                 if (ptr + size < end)
1686                         memmove_extent_buffer(leaf, ptr, ptr + size,
1687                                               end - ptr - size);
1688                 item_size -= size;
1689                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1690         }
1691         btrfs_mark_buffer_dirty(leaf);
1692         return 0;
1693 }
1694
1695 static noinline_for_stack
1696 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1697                                  struct btrfs_root *root,
1698                                  struct btrfs_path *path,
1699                                  u64 bytenr, u64 num_bytes, u64 parent,
1700                                  u64 root_objectid, u64 owner,
1701                                  u64 offset, int refs_to_add,
1702                                  struct btrfs_delayed_extent_op *extent_op)
1703 {
1704         struct btrfs_extent_inline_ref *iref;
1705         int ret;
1706
1707         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1708                                            bytenr, num_bytes, parent,
1709                                            root_objectid, owner, offset, 1);
1710         if (ret == 0) {
1711                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1712                 ret = update_inline_extent_backref(trans, root, path, iref,
1713                                                    refs_to_add, extent_op);
1714         } else if (ret == -ENOENT) {
1715                 ret = setup_inline_extent_backref(trans, root, path, iref,
1716                                                   parent, root_objectid,
1717                                                   owner, offset, refs_to_add,
1718                                                   extent_op);
1719         }
1720         return ret;
1721 }
1722
1723 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1724                                  struct btrfs_root *root,
1725                                  struct btrfs_path *path,
1726                                  u64 bytenr, u64 parent, u64 root_objectid,
1727                                  u64 owner, u64 offset, int refs_to_add)
1728 {
1729         int ret;
1730         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1731                 BUG_ON(refs_to_add != 1);
1732                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1733                                             parent, root_objectid);
1734         } else {
1735                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1736                                              parent, root_objectid,
1737                                              owner, offset, refs_to_add);
1738         }
1739         return ret;
1740 }
1741
1742 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1743                                  struct btrfs_root *root,
1744                                  struct btrfs_path *path,
1745                                  struct btrfs_extent_inline_ref *iref,
1746                                  int refs_to_drop, int is_data)
1747 {
1748         int ret;
1749
1750         BUG_ON(!is_data && refs_to_drop != 1);
1751         if (iref) {
1752                 ret = update_inline_extent_backref(trans, root, path, iref,
1753                                                    -refs_to_drop, NULL);
1754         } else if (is_data) {
1755                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1756         } else {
1757                 ret = btrfs_del_item(trans, root, path);
1758         }
1759         return ret;
1760 }
1761
1762 static int btrfs_issue_discard(struct block_device *bdev,
1763                                 u64 start, u64 len)
1764 {
1765         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1766 }
1767
1768 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1769                                 u64 num_bytes, u64 *actual_bytes)
1770 {
1771         int ret;
1772         u64 discarded_bytes = 0;
1773         struct btrfs_multi_bio *multi = NULL;
1774
1775
1776         /* Tell the block device(s) that the sectors can be discarded */
1777         ret = btrfs_map_block(&root->fs_info->mapping_tree, REQ_DISCARD,
1778                               bytenr, &num_bytes, &multi, 0);
1779         if (!ret) {
1780                 struct btrfs_bio_stripe *stripe = multi->stripes;
1781                 int i;
1782
1783
1784                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
1785                         ret = btrfs_issue_discard(stripe->dev->bdev,
1786                                                   stripe->physical,
1787                                                   stripe->length);
1788                         if (!ret)
1789                                 discarded_bytes += stripe->length;
1790                         else if (ret != -EOPNOTSUPP)
1791                                 break;
1792                 }
1793                 kfree(multi);
1794         }
1795         if (discarded_bytes && ret == -EOPNOTSUPP)
1796                 ret = 0;
1797
1798         if (actual_bytes)
1799                 *actual_bytes = discarded_bytes;
1800
1801
1802         return ret;
1803 }
1804
1805 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1806                          struct btrfs_root *root,
1807                          u64 bytenr, u64 num_bytes, u64 parent,
1808                          u64 root_objectid, u64 owner, u64 offset)
1809 {
1810         int ret;
1811         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1812                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1813
1814         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1815                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
1816                                         parent, root_objectid, (int)owner,
1817                                         BTRFS_ADD_DELAYED_REF, NULL);
1818         } else {
1819                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
1820                                         parent, root_objectid, owner, offset,
1821                                         BTRFS_ADD_DELAYED_REF, NULL);
1822         }
1823         return ret;
1824 }
1825
1826 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1827                                   struct btrfs_root *root,
1828                                   u64 bytenr, u64 num_bytes,
1829                                   u64 parent, u64 root_objectid,
1830                                   u64 owner, u64 offset, int refs_to_add,
1831                                   struct btrfs_delayed_extent_op *extent_op)
1832 {
1833         struct btrfs_path *path;
1834         struct extent_buffer *leaf;
1835         struct btrfs_extent_item *item;
1836         u64 refs;
1837         int ret;
1838         int err = 0;
1839
1840         path = btrfs_alloc_path();
1841         if (!path)
1842                 return -ENOMEM;
1843
1844         path->reada = 1;
1845         path->leave_spinning = 1;
1846         /* this will setup the path even if it fails to insert the back ref */
1847         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1848                                            path, bytenr, num_bytes, parent,
1849                                            root_objectid, owner, offset,
1850                                            refs_to_add, extent_op);
1851         if (ret == 0)
1852                 goto out;
1853
1854         if (ret != -EAGAIN) {
1855                 err = ret;
1856                 goto out;
1857         }
1858
1859         leaf = path->nodes[0];
1860         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1861         refs = btrfs_extent_refs(leaf, item);
1862         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1863         if (extent_op)
1864                 __run_delayed_extent_op(extent_op, leaf, item);
1865
1866         btrfs_mark_buffer_dirty(leaf);
1867         btrfs_release_path(path);
1868
1869         path->reada = 1;
1870         path->leave_spinning = 1;
1871
1872         /* now insert the actual backref */
1873         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1874                                     path, bytenr, parent, root_objectid,
1875                                     owner, offset, refs_to_add);
1876         BUG_ON(ret);
1877 out:
1878         btrfs_free_path(path);
1879         return err;
1880 }
1881
1882 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1883                                 struct btrfs_root *root,
1884                                 struct btrfs_delayed_ref_node *node,
1885                                 struct btrfs_delayed_extent_op *extent_op,
1886                                 int insert_reserved)
1887 {
1888         int ret = 0;
1889         struct btrfs_delayed_data_ref *ref;
1890         struct btrfs_key ins;
1891         u64 parent = 0;
1892         u64 ref_root = 0;
1893         u64 flags = 0;
1894
1895         ins.objectid = node->bytenr;
1896         ins.offset = node->num_bytes;
1897         ins.type = BTRFS_EXTENT_ITEM_KEY;
1898
1899         ref = btrfs_delayed_node_to_data_ref(node);
1900         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1901                 parent = ref->parent;
1902         else
1903                 ref_root = ref->root;
1904
1905         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1906                 if (extent_op) {
1907                         BUG_ON(extent_op->update_key);
1908                         flags |= extent_op->flags_to_set;
1909                 }
1910                 ret = alloc_reserved_file_extent(trans, root,
1911                                                  parent, ref_root, flags,
1912                                                  ref->objectid, ref->offset,
1913                                                  &ins, node->ref_mod);
1914         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1915                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1916                                              node->num_bytes, parent,
1917                                              ref_root, ref->objectid,
1918                                              ref->offset, node->ref_mod,
1919                                              extent_op);
1920         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1921                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1922                                           node->num_bytes, parent,
1923                                           ref_root, ref->objectid,
1924                                           ref->offset, node->ref_mod,
1925                                           extent_op);
1926         } else {
1927                 BUG();
1928         }
1929         return ret;
1930 }
1931
1932 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1933                                     struct extent_buffer *leaf,
1934                                     struct btrfs_extent_item *ei)
1935 {
1936         u64 flags = btrfs_extent_flags(leaf, ei);
1937         if (extent_op->update_flags) {
1938                 flags |= extent_op->flags_to_set;
1939                 btrfs_set_extent_flags(leaf, ei, flags);
1940         }
1941
1942         if (extent_op->update_key) {
1943                 struct btrfs_tree_block_info *bi;
1944                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1945                 bi = (struct btrfs_tree_block_info *)(ei + 1);
1946                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1947         }
1948 }
1949
1950 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1951                                  struct btrfs_root *root,
1952                                  struct btrfs_delayed_ref_node *node,
1953                                  struct btrfs_delayed_extent_op *extent_op)
1954 {
1955         struct btrfs_key key;
1956         struct btrfs_path *path;
1957         struct btrfs_extent_item *ei;
1958         struct extent_buffer *leaf;
1959         u32 item_size;
1960         int ret;
1961         int err = 0;
1962
1963         path = btrfs_alloc_path();
1964         if (!path)
1965                 return -ENOMEM;
1966
1967         key.objectid = node->bytenr;
1968         key.type = BTRFS_EXTENT_ITEM_KEY;
1969         key.offset = node->num_bytes;
1970
1971         path->reada = 1;
1972         path->leave_spinning = 1;
1973         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
1974                                 path, 0, 1);
1975         if (ret < 0) {
1976                 err = ret;
1977                 goto out;
1978         }
1979         if (ret > 0) {
1980                 err = -EIO;
1981                 goto out;
1982         }
1983
1984         leaf = path->nodes[0];
1985         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1986 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1987         if (item_size < sizeof(*ei)) {
1988                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1989                                              path, (u64)-1, 0);
1990                 if (ret < 0) {
1991                         err = ret;
1992                         goto out;
1993                 }
1994                 leaf = path->nodes[0];
1995                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1996         }
1997 #endif
1998         BUG_ON(item_size < sizeof(*ei));
1999         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2000         __run_delayed_extent_op(extent_op, leaf, ei);
2001
2002         btrfs_mark_buffer_dirty(leaf);
2003 out:
2004         btrfs_free_path(path);
2005         return err;
2006 }
2007
2008 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2009                                 struct btrfs_root *root,
2010                                 struct btrfs_delayed_ref_node *node,
2011                                 struct btrfs_delayed_extent_op *extent_op,
2012                                 int insert_reserved)
2013 {
2014         int ret = 0;
2015         struct btrfs_delayed_tree_ref *ref;
2016         struct btrfs_key ins;
2017         u64 parent = 0;
2018         u64 ref_root = 0;
2019
2020         ins.objectid = node->bytenr;
2021         ins.offset = node->num_bytes;
2022         ins.type = BTRFS_EXTENT_ITEM_KEY;
2023
2024         ref = btrfs_delayed_node_to_tree_ref(node);
2025         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2026                 parent = ref->parent;
2027         else
2028                 ref_root = ref->root;
2029
2030         BUG_ON(node->ref_mod != 1);
2031         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2032                 BUG_ON(!extent_op || !extent_op->update_flags ||
2033                        !extent_op->update_key);
2034                 ret = alloc_reserved_tree_block(trans, root,
2035                                                 parent, ref_root,
2036                                                 extent_op->flags_to_set,
2037                                                 &extent_op->key,
2038                                                 ref->level, &ins);
2039         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2040                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2041                                              node->num_bytes, parent, ref_root,
2042                                              ref->level, 0, 1, extent_op);
2043         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2044                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2045                                           node->num_bytes, parent, ref_root,
2046                                           ref->level, 0, 1, extent_op);
2047         } else {
2048                 BUG();
2049         }
2050         return ret;
2051 }
2052
2053 /* helper function to actually process a single delayed ref entry */
2054 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2055                                struct btrfs_root *root,
2056                                struct btrfs_delayed_ref_node *node,
2057                                struct btrfs_delayed_extent_op *extent_op,
2058                                int insert_reserved)
2059 {
2060         int ret;
2061         if (btrfs_delayed_ref_is_head(node)) {
2062                 struct btrfs_delayed_ref_head *head;
2063                 /*
2064                  * we've hit the end of the chain and we were supposed
2065                  * to insert this extent into the tree.  But, it got
2066                  * deleted before we ever needed to insert it, so all
2067                  * we have to do is clean up the accounting
2068                  */
2069                 BUG_ON(extent_op);
2070                 head = btrfs_delayed_node_to_head(node);
2071                 if (insert_reserved) {
2072                         btrfs_pin_extent(root, node->bytenr,
2073                                          node->num_bytes, 1);
2074                         if (head->is_data) {
2075                                 ret = btrfs_del_csums(trans, root,
2076                                                       node->bytenr,
2077                                                       node->num_bytes);
2078                                 BUG_ON(ret);
2079                         }
2080                 }
2081                 mutex_unlock(&head->mutex);
2082                 return 0;
2083         }
2084
2085         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2086             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2087                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2088                                            insert_reserved);
2089         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2090                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2091                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2092                                            insert_reserved);
2093         else
2094                 BUG();
2095         return ret;
2096 }
2097
2098 static noinline struct btrfs_delayed_ref_node *
2099 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2100 {
2101         struct rb_node *node;
2102         struct btrfs_delayed_ref_node *ref;
2103         int action = BTRFS_ADD_DELAYED_REF;
2104 again:
2105         /*
2106          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2107          * this prevents ref count from going down to zero when
2108          * there still are pending delayed ref.
2109          */
2110         node = rb_prev(&head->node.rb_node);
2111         while (1) {
2112                 if (!node)
2113                         break;
2114                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2115                                 rb_node);
2116                 if (ref->bytenr != head->node.bytenr)
2117                         break;
2118                 if (ref->action == action)
2119                         return ref;
2120                 node = rb_prev(node);
2121         }
2122         if (action == BTRFS_ADD_DELAYED_REF) {
2123                 action = BTRFS_DROP_DELAYED_REF;
2124                 goto again;
2125         }
2126         return NULL;
2127 }
2128
2129 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2130                                        struct btrfs_root *root,
2131                                        struct list_head *cluster)
2132 {
2133         struct btrfs_delayed_ref_root *delayed_refs;
2134         struct btrfs_delayed_ref_node *ref;
2135         struct btrfs_delayed_ref_head *locked_ref = NULL;
2136         struct btrfs_delayed_extent_op *extent_op;
2137         int ret;
2138         int count = 0;
2139         int must_insert_reserved = 0;
2140
2141         delayed_refs = &trans->transaction->delayed_refs;
2142         while (1) {
2143                 if (!locked_ref) {
2144                         /* pick a new head ref from the cluster list */
2145                         if (list_empty(cluster))
2146                                 break;
2147
2148                         locked_ref = list_entry(cluster->next,
2149                                      struct btrfs_delayed_ref_head, cluster);
2150
2151                         /* grab the lock that says we are going to process
2152                          * all the refs for this head */
2153                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2154
2155                         /*
2156                          * we may have dropped the spin lock to get the head
2157                          * mutex lock, and that might have given someone else
2158                          * time to free the head.  If that's true, it has been
2159                          * removed from our list and we can move on.
2160                          */
2161                         if (ret == -EAGAIN) {
2162                                 locked_ref = NULL;
2163                                 count++;
2164                                 continue;
2165                         }
2166                 }
2167
2168                 /*
2169                  * record the must insert reserved flag before we
2170                  * drop the spin lock.
2171                  */
2172                 must_insert_reserved = locked_ref->must_insert_reserved;
2173                 locked_ref->must_insert_reserved = 0;
2174
2175                 extent_op = locked_ref->extent_op;
2176                 locked_ref->extent_op = NULL;
2177
2178                 /*
2179                  * locked_ref is the head node, so we have to go one
2180                  * node back for any delayed ref updates
2181                  */
2182                 ref = select_delayed_ref(locked_ref);
2183                 if (!ref) {
2184                         /* All delayed refs have been processed, Go ahead
2185                          * and send the head node to run_one_delayed_ref,
2186                          * so that any accounting fixes can happen
2187                          */
2188                         ref = &locked_ref->node;
2189
2190                         if (extent_op && must_insert_reserved) {
2191                                 kfree(extent_op);
2192                                 extent_op = NULL;
2193                         }
2194
2195                         if (extent_op) {
2196                                 spin_unlock(&delayed_refs->lock);
2197
2198                                 ret = run_delayed_extent_op(trans, root,
2199                                                             ref, extent_op);
2200                                 BUG_ON(ret);
2201                                 kfree(extent_op);
2202
2203                                 cond_resched();
2204                                 spin_lock(&delayed_refs->lock);
2205                                 continue;
2206                         }
2207
2208                         list_del_init(&locked_ref->cluster);
2209                         locked_ref = NULL;
2210                 }
2211
2212                 ref->in_tree = 0;
2213                 rb_erase(&ref->rb_node, &delayed_refs->root);
2214                 delayed_refs->num_entries--;
2215
2216                 spin_unlock(&delayed_refs->lock);
2217
2218                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2219                                           must_insert_reserved);
2220                 BUG_ON(ret);
2221
2222                 btrfs_put_delayed_ref(ref);
2223                 kfree(extent_op);
2224                 count++;
2225
2226                 cond_resched();
2227                 spin_lock(&delayed_refs->lock);
2228         }
2229         return count;
2230 }
2231
2232 /*
2233  * this starts processing the delayed reference count updates and
2234  * extent insertions we have queued up so far.  count can be
2235  * 0, which means to process everything in the tree at the start
2236  * of the run (but not newly added entries), or it can be some target
2237  * number you'd like to process.
2238  */
2239 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2240                            struct btrfs_root *root, unsigned long count)
2241 {
2242         struct rb_node *node;
2243         struct btrfs_delayed_ref_root *delayed_refs;
2244         struct btrfs_delayed_ref_node *ref;
2245         struct list_head cluster;
2246         int ret;
2247         int run_all = count == (unsigned long)-1;
2248         int run_most = 0;
2249
2250         if (root == root->fs_info->extent_root)
2251                 root = root->fs_info->tree_root;
2252
2253         delayed_refs = &trans->transaction->delayed_refs;
2254         INIT_LIST_HEAD(&cluster);
2255 again:
2256         spin_lock(&delayed_refs->lock);
2257         if (count == 0) {
2258                 count = delayed_refs->num_entries * 2;
2259                 run_most = 1;
2260         }
2261         while (1) {
2262                 if (!(run_all || run_most) &&
2263                     delayed_refs->num_heads_ready < 64)
2264                         break;
2265
2266                 /*
2267                  * go find something we can process in the rbtree.  We start at
2268                  * the beginning of the tree, and then build a cluster
2269                  * of refs to process starting at the first one we are able to
2270                  * lock
2271                  */
2272                 ret = btrfs_find_ref_cluster(trans, &cluster,
2273                                              delayed_refs->run_delayed_start);
2274                 if (ret)
2275                         break;
2276
2277                 ret = run_clustered_refs(trans, root, &cluster);
2278                 BUG_ON(ret < 0);
2279
2280                 count -= min_t(unsigned long, ret, count);
2281
2282                 if (count == 0)
2283                         break;
2284         }
2285
2286         if (run_all) {
2287                 node = rb_first(&delayed_refs->root);
2288                 if (!node)
2289                         goto out;
2290                 count = (unsigned long)-1;
2291
2292                 while (node) {
2293                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2294                                        rb_node);
2295                         if (btrfs_delayed_ref_is_head(ref)) {
2296                                 struct btrfs_delayed_ref_head *head;
2297
2298                                 head = btrfs_delayed_node_to_head(ref);
2299                                 atomic_inc(&ref->refs);
2300
2301                                 spin_unlock(&delayed_refs->lock);
2302                                 /*
2303                                  * Mutex was contended, block until it's
2304                                  * released and try again
2305                                  */
2306                                 mutex_lock(&head->mutex);
2307                                 mutex_unlock(&head->mutex);
2308
2309                                 btrfs_put_delayed_ref(ref);
2310                                 cond_resched();
2311                                 goto again;
2312                         }
2313                         node = rb_next(node);
2314                 }
2315                 spin_unlock(&delayed_refs->lock);
2316                 schedule_timeout(1);
2317                 goto again;
2318         }
2319 out:
2320         spin_unlock(&delayed_refs->lock);
2321         return 0;
2322 }
2323
2324 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2325                                 struct btrfs_root *root,
2326                                 u64 bytenr, u64 num_bytes, u64 flags,
2327                                 int is_data)
2328 {
2329         struct btrfs_delayed_extent_op *extent_op;
2330         int ret;
2331
2332         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2333         if (!extent_op)
2334                 return -ENOMEM;
2335
2336         extent_op->flags_to_set = flags;
2337         extent_op->update_flags = 1;
2338         extent_op->update_key = 0;
2339         extent_op->is_data = is_data ? 1 : 0;
2340
2341         ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2342         if (ret)
2343                 kfree(extent_op);
2344         return ret;
2345 }
2346
2347 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2348                                       struct btrfs_root *root,
2349                                       struct btrfs_path *path,
2350                                       u64 objectid, u64 offset, u64 bytenr)
2351 {
2352         struct btrfs_delayed_ref_head *head;
2353         struct btrfs_delayed_ref_node *ref;
2354         struct btrfs_delayed_data_ref *data_ref;
2355         struct btrfs_delayed_ref_root *delayed_refs;
2356         struct rb_node *node;
2357         int ret = 0;
2358
2359         ret = -ENOENT;
2360         delayed_refs = &trans->transaction->delayed_refs;
2361         spin_lock(&delayed_refs->lock);
2362         head = btrfs_find_delayed_ref_head(trans, bytenr);
2363         if (!head)
2364                 goto out;
2365
2366         if (!mutex_trylock(&head->mutex)) {
2367                 atomic_inc(&head->node.refs);
2368                 spin_unlock(&delayed_refs->lock);
2369
2370                 btrfs_release_path(path);
2371
2372                 /*
2373                  * Mutex was contended, block until it's released and let
2374                  * caller try again
2375                  */
2376                 mutex_lock(&head->mutex);
2377                 mutex_unlock(&head->mutex);
2378                 btrfs_put_delayed_ref(&head->node);
2379                 return -EAGAIN;
2380         }
2381
2382         node = rb_prev(&head->node.rb_node);
2383         if (!node)
2384                 goto out_unlock;
2385
2386         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2387
2388         if (ref->bytenr != bytenr)
2389                 goto out_unlock;
2390
2391         ret = 1;
2392         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2393                 goto out_unlock;
2394
2395         data_ref = btrfs_delayed_node_to_data_ref(ref);
2396
2397         node = rb_prev(node);
2398         if (node) {
2399                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2400                 if (ref->bytenr == bytenr)
2401                         goto out_unlock;
2402         }
2403
2404         if (data_ref->root != root->root_key.objectid ||
2405             data_ref->objectid != objectid || data_ref->offset != offset)
2406                 goto out_unlock;
2407
2408         ret = 0;
2409 out_unlock:
2410         mutex_unlock(&head->mutex);
2411 out:
2412         spin_unlock(&delayed_refs->lock);
2413         return ret;
2414 }
2415
2416 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2417                                         struct btrfs_root *root,
2418                                         struct btrfs_path *path,
2419                                         u64 objectid, u64 offset, u64 bytenr)
2420 {
2421         struct btrfs_root *extent_root = root->fs_info->extent_root;
2422         struct extent_buffer *leaf;
2423         struct btrfs_extent_data_ref *ref;
2424         struct btrfs_extent_inline_ref *iref;
2425         struct btrfs_extent_item *ei;
2426         struct btrfs_key key;
2427         u32 item_size;
2428         int ret;
2429
2430         key.objectid = bytenr;
2431         key.offset = (u64)-1;
2432         key.type = BTRFS_EXTENT_ITEM_KEY;
2433
2434         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2435         if (ret < 0)
2436                 goto out;
2437         BUG_ON(ret == 0);
2438
2439         ret = -ENOENT;
2440         if (path->slots[0] == 0)
2441                 goto out;
2442
2443         path->slots[0]--;
2444         leaf = path->nodes[0];
2445         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2446
2447         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2448                 goto out;
2449
2450         ret = 1;
2451         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2452 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2453         if (item_size < sizeof(*ei)) {
2454                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2455                 goto out;
2456         }
2457 #endif
2458         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2459
2460         if (item_size != sizeof(*ei) +
2461             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2462                 goto out;
2463
2464         if (btrfs_extent_generation(leaf, ei) <=
2465             btrfs_root_last_snapshot(&root->root_item))
2466                 goto out;
2467
2468         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2469         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2470             BTRFS_EXTENT_DATA_REF_KEY)
2471                 goto out;
2472
2473         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2474         if (btrfs_extent_refs(leaf, ei) !=
2475             btrfs_extent_data_ref_count(leaf, ref) ||
2476             btrfs_extent_data_ref_root(leaf, ref) !=
2477             root->root_key.objectid ||
2478             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2479             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2480                 goto out;
2481
2482         ret = 0;
2483 out:
2484         return ret;
2485 }
2486
2487 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2488                           struct btrfs_root *root,
2489                           u64 objectid, u64 offset, u64 bytenr)
2490 {
2491         struct btrfs_path *path;
2492         int ret;
2493         int ret2;
2494
2495         path = btrfs_alloc_path();
2496         if (!path)
2497                 return -ENOENT;
2498
2499         do {
2500                 ret = check_committed_ref(trans, root, path, objectid,
2501                                           offset, bytenr);
2502                 if (ret && ret != -ENOENT)
2503                         goto out;
2504
2505                 ret2 = check_delayed_ref(trans, root, path, objectid,
2506                                          offset, bytenr);
2507         } while (ret2 == -EAGAIN);
2508
2509         if (ret2 && ret2 != -ENOENT) {
2510                 ret = ret2;
2511                 goto out;
2512         }
2513
2514         if (ret != -ENOENT || ret2 != -ENOENT)
2515                 ret = 0;
2516 out:
2517         btrfs_free_path(path);
2518         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2519                 WARN_ON(ret > 0);
2520         return ret;
2521 }
2522
2523 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2524                            struct btrfs_root *root,
2525                            struct extent_buffer *buf,
2526                            int full_backref, int inc)
2527 {
2528         u64 bytenr;
2529         u64 num_bytes;
2530         u64 parent;
2531         u64 ref_root;
2532         u32 nritems;
2533         struct btrfs_key key;
2534         struct btrfs_file_extent_item *fi;
2535         int i;
2536         int level;
2537         int ret = 0;
2538         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2539                             u64, u64, u64, u64, u64, u64);
2540
2541         ref_root = btrfs_header_owner(buf);
2542         nritems = btrfs_header_nritems(buf);
2543         level = btrfs_header_level(buf);
2544
2545         if (!root->ref_cows && level == 0)
2546                 return 0;
2547
2548         if (inc)
2549                 process_func = btrfs_inc_extent_ref;
2550         else
2551                 process_func = btrfs_free_extent;
2552
2553         if (full_backref)
2554                 parent = buf->start;
2555         else
2556                 parent = 0;
2557
2558         for (i = 0; i < nritems; i++) {
2559                 if (level == 0) {
2560                         btrfs_item_key_to_cpu(buf, &key, i);
2561                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2562                                 continue;
2563                         fi = btrfs_item_ptr(buf, i,
2564                                             struct btrfs_file_extent_item);
2565                         if (btrfs_file_extent_type(buf, fi) ==
2566                             BTRFS_FILE_EXTENT_INLINE)
2567                                 continue;
2568                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2569                         if (bytenr == 0)
2570                                 continue;
2571
2572                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2573                         key.offset -= btrfs_file_extent_offset(buf, fi);
2574                         ret = process_func(trans, root, bytenr, num_bytes,
2575                                            parent, ref_root, key.objectid,
2576                                            key.offset);
2577                         if (ret)
2578                                 goto fail;
2579                 } else {
2580                         bytenr = btrfs_node_blockptr(buf, i);
2581                         num_bytes = btrfs_level_size(root, level - 1);
2582                         ret = process_func(trans, root, bytenr, num_bytes,
2583                                            parent, ref_root, level - 1, 0);
2584                         if (ret)
2585                                 goto fail;
2586                 }
2587         }
2588         return 0;
2589 fail:
2590         BUG();
2591         return ret;
2592 }
2593
2594 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2595                   struct extent_buffer *buf, int full_backref)
2596 {
2597         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2598 }
2599
2600 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2601                   struct extent_buffer *buf, int full_backref)
2602 {
2603         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2604 }
2605
2606 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2607                                  struct btrfs_root *root,
2608                                  struct btrfs_path *path,
2609                                  struct btrfs_block_group_cache *cache)
2610 {
2611         int ret;
2612         struct btrfs_root *extent_root = root->fs_info->extent_root;
2613         unsigned long bi;
2614         struct extent_buffer *leaf;
2615
2616         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2617         if (ret < 0)
2618                 goto fail;
2619         BUG_ON(ret);
2620
2621         leaf = path->nodes[0];
2622         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2623         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2624         btrfs_mark_buffer_dirty(leaf);
2625         btrfs_release_path(path);
2626 fail:
2627         if (ret)
2628                 return ret;
2629         return 0;
2630
2631 }
2632
2633 static struct btrfs_block_group_cache *
2634 next_block_group(struct btrfs_root *root,
2635                  struct btrfs_block_group_cache *cache)
2636 {
2637         struct rb_node *node;
2638         spin_lock(&root->fs_info->block_group_cache_lock);
2639         node = rb_next(&cache->cache_node);
2640         btrfs_put_block_group(cache);
2641         if (node) {
2642                 cache = rb_entry(node, struct btrfs_block_group_cache,
2643                                  cache_node);
2644                 btrfs_get_block_group(cache);
2645         } else
2646                 cache = NULL;
2647         spin_unlock(&root->fs_info->block_group_cache_lock);
2648         return cache;
2649 }
2650
2651 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2652                             struct btrfs_trans_handle *trans,
2653                             struct btrfs_path *path)
2654 {
2655         struct btrfs_root *root = block_group->fs_info->tree_root;
2656         struct inode *inode = NULL;
2657         u64 alloc_hint = 0;
2658         int dcs = BTRFS_DC_ERROR;
2659         int num_pages = 0;
2660         int retries = 0;
2661         int ret = 0;
2662
2663         /*
2664          * If this block group is smaller than 100 megs don't bother caching the
2665          * block group.
2666          */
2667         if (block_group->key.offset < (100 * 1024 * 1024)) {
2668                 spin_lock(&block_group->lock);
2669                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2670                 spin_unlock(&block_group->lock);
2671                 return 0;
2672         }
2673
2674 again:
2675         inode = lookup_free_space_inode(root, block_group, path);
2676         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2677                 ret = PTR_ERR(inode);
2678                 btrfs_release_path(path);
2679                 goto out;
2680         }
2681
2682         if (IS_ERR(inode)) {
2683                 BUG_ON(retries);
2684                 retries++;
2685
2686                 if (block_group->ro)
2687                         goto out_free;
2688
2689                 ret = create_free_space_inode(root, trans, block_group, path);
2690                 if (ret)
2691                         goto out_free;
2692                 goto again;
2693         }
2694
2695         /*
2696          * We want to set the generation to 0, that way if anything goes wrong
2697          * from here on out we know not to trust this cache when we load up next
2698          * time.
2699          */
2700         BTRFS_I(inode)->generation = 0;
2701         ret = btrfs_update_inode(trans, root, inode);
2702         WARN_ON(ret);
2703
2704         if (i_size_read(inode) > 0) {
2705                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2706                                                       inode);
2707                 if (ret)
2708                         goto out_put;
2709         }
2710
2711         spin_lock(&block_group->lock);
2712         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2713                 /* We're not cached, don't bother trying to write stuff out */
2714                 dcs = BTRFS_DC_WRITTEN;
2715                 spin_unlock(&block_group->lock);
2716                 goto out_put;
2717         }
2718         spin_unlock(&block_group->lock);
2719
2720         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2721         if (!num_pages)
2722                 num_pages = 1;
2723
2724         /*
2725          * Just to make absolutely sure we have enough space, we're going to
2726          * preallocate 12 pages worth of space for each block group.  In
2727          * practice we ought to use at most 8, but we need extra space so we can
2728          * add our header and have a terminator between the extents and the
2729          * bitmaps.
2730          */
2731         num_pages *= 16;
2732         num_pages *= PAGE_CACHE_SIZE;
2733
2734         ret = btrfs_check_data_free_space(inode, num_pages);
2735         if (ret)
2736                 goto out_put;
2737
2738         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2739                                               num_pages, num_pages,
2740                                               &alloc_hint);
2741         if (!ret)
2742                 dcs = BTRFS_DC_SETUP;
2743         btrfs_free_reserved_data_space(inode, num_pages);
2744 out_put:
2745         iput(inode);
2746 out_free:
2747         btrfs_release_path(path);
2748 out:
2749         spin_lock(&block_group->lock);
2750         block_group->disk_cache_state = dcs;
2751         spin_unlock(&block_group->lock);
2752
2753         return ret;
2754 }
2755
2756 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2757                                    struct btrfs_root *root)
2758 {
2759         struct btrfs_block_group_cache *cache;
2760         int err = 0;
2761         struct btrfs_path *path;
2762         u64 last = 0;
2763
2764         path = btrfs_alloc_path();
2765         if (!path)
2766                 return -ENOMEM;
2767
2768 again:
2769         while (1) {
2770                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2771                 while (cache) {
2772                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2773                                 break;
2774                         cache = next_block_group(root, cache);
2775                 }
2776                 if (!cache) {
2777                         if (last == 0)
2778                                 break;
2779                         last = 0;
2780                         continue;
2781                 }
2782                 err = cache_save_setup(cache, trans, path);
2783                 last = cache->key.objectid + cache->key.offset;
2784                 btrfs_put_block_group(cache);
2785         }
2786
2787         while (1) {
2788                 if (last == 0) {
2789                         err = btrfs_run_delayed_refs(trans, root,
2790                                                      (unsigned long)-1);
2791                         BUG_ON(err);
2792                 }
2793
2794                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2795                 while (cache) {
2796                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2797                                 btrfs_put_block_group(cache);
2798                                 goto again;
2799                         }
2800
2801                         if (cache->dirty)
2802                                 break;
2803                         cache = next_block_group(root, cache);
2804                 }
2805                 if (!cache) {
2806                         if (last == 0)
2807                                 break;
2808                         last = 0;
2809                         continue;
2810                 }
2811
2812                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
2813                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
2814                 cache->dirty = 0;
2815                 last = cache->key.objectid + cache->key.offset;
2816
2817                 err = write_one_cache_group(trans, root, path, cache);
2818                 BUG_ON(err);
2819                 btrfs_put_block_group(cache);
2820         }
2821
2822         while (1) {
2823                 /*
2824                  * I don't think this is needed since we're just marking our
2825                  * preallocated extent as written, but just in case it can't
2826                  * hurt.
2827                  */
2828                 if (last == 0) {
2829                         err = btrfs_run_delayed_refs(trans, root,
2830                                                      (unsigned long)-1);
2831                         BUG_ON(err);
2832                 }
2833
2834                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2835                 while (cache) {
2836                         /*
2837                          * Really this shouldn't happen, but it could if we
2838                          * couldn't write the entire preallocated extent and
2839                          * splitting the extent resulted in a new block.
2840                          */
2841                         if (cache->dirty) {
2842                                 btrfs_put_block_group(cache);
2843                                 goto again;
2844                         }
2845                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2846                                 break;
2847                         cache = next_block_group(root, cache);
2848                 }
2849                 if (!cache) {
2850                         if (last == 0)
2851                                 break;
2852                         last = 0;
2853                         continue;
2854                 }
2855
2856                 btrfs_write_out_cache(root, trans, cache, path);
2857
2858                 /*
2859                  * If we didn't have an error then the cache state is still
2860                  * NEED_WRITE, so we can set it to WRITTEN.
2861                  */
2862                 if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2863                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
2864                 last = cache->key.objectid + cache->key.offset;
2865                 btrfs_put_block_group(cache);
2866         }
2867
2868         btrfs_free_path(path);
2869         return 0;
2870 }
2871
2872 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
2873 {
2874         struct btrfs_block_group_cache *block_group;
2875         int readonly = 0;
2876
2877         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
2878         if (!block_group || block_group->ro)
2879                 readonly = 1;
2880         if (block_group)
2881                 btrfs_put_block_group(block_group);
2882         return readonly;
2883 }
2884
2885 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2886                              u64 total_bytes, u64 bytes_used,
2887                              struct btrfs_space_info **space_info)
2888 {
2889         struct btrfs_space_info *found;
2890         int i;
2891         int factor;
2892
2893         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2894                      BTRFS_BLOCK_GROUP_RAID10))
2895                 factor = 2;
2896         else
2897                 factor = 1;
2898
2899         found = __find_space_info(info, flags);
2900         if (found) {
2901                 spin_lock(&found->lock);
2902                 found->total_bytes += total_bytes;
2903                 found->disk_total += total_bytes * factor;
2904                 found->bytes_used += bytes_used;
2905                 found->disk_used += bytes_used * factor;
2906                 found->full = 0;
2907                 spin_unlock(&found->lock);
2908                 *space_info = found;
2909                 return 0;
2910         }
2911         found = kzalloc(sizeof(*found), GFP_NOFS);
2912         if (!found)
2913                 return -ENOMEM;
2914
2915         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
2916                 INIT_LIST_HEAD(&found->block_groups[i]);
2917         init_rwsem(&found->groups_sem);
2918         spin_lock_init(&found->lock);
2919         found->flags = flags & (BTRFS_BLOCK_GROUP_DATA |
2920                                 BTRFS_BLOCK_GROUP_SYSTEM |
2921                                 BTRFS_BLOCK_GROUP_METADATA);
2922         found->total_bytes = total_bytes;
2923         found->disk_total = total_bytes * factor;
2924         found->bytes_used = bytes_used;
2925         found->disk_used = bytes_used * factor;
2926         found->bytes_pinned = 0;
2927         found->bytes_reserved = 0;
2928         found->bytes_readonly = 0;
2929         found->bytes_may_use = 0;
2930         found->full = 0;
2931         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
2932         found->chunk_alloc = 0;
2933         found->flush = 0;
2934         init_waitqueue_head(&found->wait);
2935         *space_info = found;
2936         list_add_rcu(&found->list, &info->space_info);
2937         return 0;
2938 }
2939
2940 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
2941 {
2942         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
2943                                    BTRFS_BLOCK_GROUP_RAID1 |
2944                                    BTRFS_BLOCK_GROUP_RAID10 |
2945                                    BTRFS_BLOCK_GROUP_DUP);
2946         if (extra_flags) {
2947                 if (flags & BTRFS_BLOCK_GROUP_DATA)
2948                         fs_info->avail_data_alloc_bits |= extra_flags;
2949                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
2950                         fs_info->avail_metadata_alloc_bits |= extra_flags;
2951                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2952                         fs_info->avail_system_alloc_bits |= extra_flags;
2953         }
2954 }
2955
2956 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
2957 {
2958         /*
2959          * we add in the count of missing devices because we want
2960          * to make sure that any RAID levels on a degraded FS
2961          * continue to be honored.
2962          */
2963         u64 num_devices = root->fs_info->fs_devices->rw_devices +
2964                 root->fs_info->fs_devices->missing_devices;
2965
2966         if (num_devices == 1)
2967                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
2968         if (num_devices < 4)
2969                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
2970
2971         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
2972             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2973                       BTRFS_BLOCK_GROUP_RAID10))) {
2974                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
2975         }
2976
2977         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
2978             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
2979                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
2980         }
2981
2982         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
2983             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
2984              (flags & BTRFS_BLOCK_GROUP_RAID10) |
2985              (flags & BTRFS_BLOCK_GROUP_DUP)))
2986                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
2987         return flags;
2988 }
2989
2990 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
2991 {
2992         if (flags & BTRFS_BLOCK_GROUP_DATA)
2993                 flags |= root->fs_info->avail_data_alloc_bits &
2994                          root->fs_info->data_alloc_profile;
2995         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2996                 flags |= root->fs_info->avail_system_alloc_bits &
2997                          root->fs_info->system_alloc_profile;
2998         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
2999                 flags |= root->fs_info->avail_metadata_alloc_bits &
3000                          root->fs_info->metadata_alloc_profile;
3001         return btrfs_reduce_alloc_profile(root, flags);
3002 }
3003
3004 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3005 {
3006         u64 flags;
3007
3008         if (data)
3009                 flags = BTRFS_BLOCK_GROUP_DATA;
3010         else if (root == root->fs_info->chunk_root)
3011                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3012         else
3013                 flags = BTRFS_BLOCK_GROUP_METADATA;
3014
3015         return get_alloc_profile(root, flags);
3016 }
3017
3018 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
3019 {
3020         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3021                                                        BTRFS_BLOCK_GROUP_DATA);
3022 }
3023
3024 /*
3025  * This will check the space that the inode allocates from to make sure we have
3026  * enough space for bytes.
3027  */
3028 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3029 {
3030         struct btrfs_space_info *data_sinfo;
3031         struct btrfs_root *root = BTRFS_I(inode)->root;
3032         u64 used;
3033         int ret = 0, committed = 0, alloc_chunk = 1;
3034
3035         /* make sure bytes are sectorsize aligned */
3036         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3037
3038         if (root == root->fs_info->tree_root ||
3039             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3040                 alloc_chunk = 0;
3041                 committed = 1;
3042         }
3043
3044         data_sinfo = BTRFS_I(inode)->space_info;
3045         if (!data_sinfo)
3046                 goto alloc;
3047
3048 again:
3049         /* make sure we have enough space to handle the data first */
3050         spin_lock(&data_sinfo->lock);
3051         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3052                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3053                 data_sinfo->bytes_may_use;
3054
3055         if (used + bytes > data_sinfo->total_bytes) {
3056                 struct btrfs_trans_handle *trans;
3057
3058                 /*
3059                  * if we don't have enough free bytes in this space then we need
3060                  * to alloc a new chunk.
3061                  */
3062                 if (!data_sinfo->full && alloc_chunk) {
3063                         u64 alloc_target;
3064
3065                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3066                         spin_unlock(&data_sinfo->lock);
3067 alloc:
3068                         alloc_target = btrfs_get_alloc_profile(root, 1);
3069                         trans = btrfs_join_transaction(root);
3070                         if (IS_ERR(trans))
3071                                 return PTR_ERR(trans);
3072
3073                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3074                                              bytes + 2 * 1024 * 1024,
3075                                              alloc_target,
3076                                              CHUNK_ALLOC_NO_FORCE);
3077                         btrfs_end_transaction(trans, root);
3078                         if (ret < 0) {
3079                                 if (ret != -ENOSPC)
3080                                         return ret;
3081                                 else
3082                                         goto commit_trans;
3083                         }
3084
3085                         if (!data_sinfo) {
3086                                 btrfs_set_inode_space_info(root, inode);
3087                                 data_sinfo = BTRFS_I(inode)->space_info;
3088                         }
3089                         goto again;
3090                 }
3091
3092                 /*
3093                  * If we have less pinned bytes than we want to allocate then
3094                  * don't bother committing the transaction, it won't help us.
3095                  */
3096                 if (data_sinfo->bytes_pinned < bytes)
3097                         committed = 1;
3098                 spin_unlock(&data_sinfo->lock);
3099
3100                 /* commit the current transaction and try again */
3101 commit_trans:
3102                 if (!committed &&
3103                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3104                         committed = 1;
3105                         trans = btrfs_join_transaction(root);
3106                         if (IS_ERR(trans))
3107                                 return PTR_ERR(trans);
3108                         ret = btrfs_commit_transaction(trans, root);
3109                         if (ret)
3110                                 return ret;
3111                         goto again;
3112                 }
3113
3114                 return -ENOSPC;
3115         }
3116         data_sinfo->bytes_may_use += bytes;
3117         BTRFS_I(inode)->reserved_bytes += bytes;
3118         spin_unlock(&data_sinfo->lock);
3119
3120         return 0;
3121 }
3122
3123 /*
3124  * called when we are clearing an delalloc extent from the
3125  * inode's io_tree or there was an error for whatever reason
3126  * after calling btrfs_check_data_free_space
3127  */
3128 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3129 {
3130         struct btrfs_root *root = BTRFS_I(inode)->root;
3131         struct btrfs_space_info *data_sinfo;
3132
3133         /* make sure bytes are sectorsize aligned */
3134         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3135
3136         data_sinfo = BTRFS_I(inode)->space_info;
3137         spin_lock(&data_sinfo->lock);
3138         data_sinfo->bytes_may_use -= bytes;
3139         BTRFS_I(inode)->reserved_bytes -= bytes;
3140         spin_unlock(&data_sinfo->lock);
3141 }
3142
3143 static void force_metadata_allocation(struct btrfs_fs_info *info)
3144 {
3145         struct list_head *head = &info->space_info;
3146         struct btrfs_space_info *found;
3147
3148         rcu_read_lock();
3149         list_for_each_entry_rcu(found, head, list) {
3150                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3151                         found->force_alloc = CHUNK_ALLOC_FORCE;
3152         }
3153         rcu_read_unlock();
3154 }
3155
3156 static int should_alloc_chunk(struct btrfs_root *root,
3157                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3158                               int force)
3159 {
3160         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3161         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3162         u64 thresh;
3163
3164         if (force == CHUNK_ALLOC_FORCE)
3165                 return 1;
3166
3167         /*
3168          * in limited mode, we want to have some free space up to
3169          * about 1% of the FS size.
3170          */
3171         if (force == CHUNK_ALLOC_LIMITED) {
3172                 thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
3173                 thresh = max_t(u64, 64 * 1024 * 1024,
3174                                div_factor_fine(thresh, 1));
3175
3176                 if (num_bytes - num_allocated < thresh)
3177                         return 1;
3178         }
3179
3180         /*
3181          * we have two similar checks here, one based on percentage
3182          * and once based on a hard number of 256MB.  The idea
3183          * is that if we have a good amount of free
3184          * room, don't allocate a chunk.  A good mount is
3185          * less than 80% utilized of the chunks we have allocated,
3186          * or more than 256MB free
3187          */
3188         if (num_allocated + alloc_bytes + 256 * 1024 * 1024 < num_bytes)
3189                 return 0;
3190
3191         if (num_allocated + alloc_bytes < div_factor(num_bytes, 8))
3192                 return 0;
3193
3194         thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
3195
3196         /* 256MB or 5% of the FS */
3197         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));
3198
3199         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 3))
3200                 return 0;
3201         return 1;
3202 }
3203
3204 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3205                           struct btrfs_root *extent_root, u64 alloc_bytes,
3206                           u64 flags, int force)
3207 {
3208         struct btrfs_space_info *space_info;
3209         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3210         int wait_for_alloc = 0;
3211         int ret = 0;
3212
3213         flags = btrfs_reduce_alloc_profile(extent_root, flags);
3214
3215         space_info = __find_space_info(extent_root->fs_info, flags);
3216         if (!space_info) {
3217                 ret = update_space_info(extent_root->fs_info, flags,
3218                                         0, 0, &space_info);
3219                 BUG_ON(ret);
3220         }
3221         BUG_ON(!space_info);
3222
3223 again:
3224         spin_lock(&space_info->lock);
3225         if (space_info->force_alloc)
3226                 force = space_info->force_alloc;
3227         if (space_info->full) {
3228                 spin_unlock(&space_info->lock);
3229                 return 0;
3230         }
3231
3232         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3233                 spin_unlock(&space_info->lock);
3234                 return 0;
3235         } else if (space_info->chunk_alloc) {
3236                 wait_for_alloc = 1;
3237         } else {
3238                 space_info->chunk_alloc = 1;
3239         }
3240
3241         spin_unlock(&space_info->lock);
3242
3243         mutex_lock(&fs_info->chunk_mutex);
3244
3245         /*
3246          * The chunk_mutex is held throughout the entirety of a chunk
3247          * allocation, so once we've acquired the chunk_mutex we know that the
3248          * other guy is done and we need to recheck and see if we should
3249          * allocate.
3250          */
3251         if (wait_for_alloc) {
3252                 mutex_unlock(&fs_info->chunk_mutex);
3253                 wait_for_alloc = 0;
3254                 goto again;
3255         }
3256
3257         /*
3258          * If we have mixed data/metadata chunks we want to make sure we keep
3259          * allocating mixed chunks instead of individual chunks.
3260          */
3261         if (btrfs_mixed_space_info(space_info))
3262                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3263
3264         /*
3265          * if we're doing a data chunk, go ahead and make sure that
3266          * we keep a reasonable number of metadata chunks allocated in the
3267          * FS as well.
3268          */
3269         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3270                 fs_info->data_chunk_allocations++;
3271                 if (!(fs_info->data_chunk_allocations %
3272                       fs_info->metadata_ratio))
3273                         force_metadata_allocation(fs_info);
3274         }
3275
3276         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3277         if (ret < 0 && ret != -ENOSPC)
3278                 goto out;
3279
3280         spin_lock(&space_info->lock);
3281         if (ret)
3282                 space_info->full = 1;
3283         else
3284                 ret = 1;
3285
3286         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3287         space_info->chunk_alloc = 0;
3288         spin_unlock(&space_info->lock);
3289 out:
3290         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3291         return ret;
3292 }
3293
3294 /*
3295  * shrink metadata reservation for delalloc
3296  */
3297 static int shrink_delalloc(struct btrfs_trans_handle *trans,
3298                            struct btrfs_root *root, u64 to_reclaim, int sync)
3299 {
3300         struct btrfs_block_rsv *block_rsv;
3301         struct btrfs_space_info *space_info;
3302         u64 reserved;
3303         u64 max_reclaim;
3304         u64 reclaimed = 0;
3305         long time_left;
3306         int nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3307         int loops = 0;
3308         unsigned long progress;
3309
3310         block_rsv = &root->fs_info->delalloc_block_rsv;
3311         space_info = block_rsv->space_info;
3312
3313         smp_mb();
3314         reserved = space_info->bytes_reserved;
3315         progress = space_info->reservation_progress;
3316
3317         if (reserved == 0)
3318                 return 0;
3319
3320         smp_mb();
3321         if (root->fs_info->delalloc_bytes == 0) {
3322                 if (trans)
3323                         return 0;
3324                 btrfs_wait_ordered_extents(root, 0, 0);
3325                 return 0;
3326         }
3327
3328         max_reclaim = min(reserved, to_reclaim);
3329
3330         while (loops < 1024) {
3331                 /* have the flusher threads jump in and do some IO */
3332                 smp_mb();
3333                 nr_pages = min_t(unsigned long, nr_pages,
3334                        root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
3335                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages);
3336
3337                 spin_lock(&space_info->lock);
3338                 if (reserved > space_info->bytes_reserved)
3339                         reclaimed += reserved - space_info->bytes_reserved;
3340                 reserved = space_info->bytes_reserved;
3341                 spin_unlock(&space_info->lock);
3342
3343                 loops++;
3344
3345                 if (reserved == 0 || reclaimed >= max_reclaim)
3346                         break;
3347
3348                 if (trans && trans->transaction->blocked)
3349                         return -EAGAIN;
3350
3351                 time_left = schedule_timeout_interruptible(1);
3352
3353                 /* We were interrupted, exit */
3354                 if (time_left)
3355                         break;
3356
3357                 /* we've kicked the IO a few times, if anything has been freed,
3358                  * exit.  There is no sense in looping here for a long time
3359                  * when we really need to commit the transaction, or there are
3360                  * just too many writers without enough free space
3361                  */
3362
3363                 if (loops > 3) {
3364                         smp_mb();
3365                         if (progress != space_info->reservation_progress)
3366                                 break;
3367                 }
3368
3369         }
3370         if (reclaimed >= to_reclaim && !trans)
3371                 btrfs_wait_ordered_extents(root, 0, 0);
3372         return reclaimed >= to_reclaim;
3373 }
3374
3375 /*
3376  * Retries tells us how many times we've called reserve_metadata_bytes.  The
3377  * idea is if this is the first call (retries == 0) then we will add to our
3378  * reserved count if we can't make the allocation in order to hold our place
3379  * while we go and try and free up space.  That way for retries > 1 we don't try
3380  * and add space, we just check to see if the amount of unused space is >= the
3381  * total space, meaning that our reservation is valid.
3382  *
3383  * However if we don't intend to retry this reservation, pass -1 as retries so
3384  * that it short circuits this logic.
3385  */
3386 static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
3387                                   struct btrfs_root *root,
3388                                   struct btrfs_block_rsv *block_rsv,
3389                                   u64 orig_bytes, int flush)
3390 {
3391         struct btrfs_space_info *space_info = block_rsv->space_info;
3392         u64 unused;
3393         u64 num_bytes = orig_bytes;
3394         int retries = 0;
3395         int ret = 0;
3396         bool committed = false;
3397         bool flushing = false;
3398
3399 again:
3400         ret = 0;
3401         spin_lock(&space_info->lock);
3402         /*
3403          * We only want to wait if somebody other than us is flushing and we are
3404          * actually alloed to flush.
3405          */
3406         while (flush && !flushing && space_info->flush) {
3407                 spin_unlock(&space_info->lock);
3408                 /*
3409                  * If we have a trans handle we can't wait because the flusher
3410                  * may have to commit the transaction, which would mean we would
3411                  * deadlock since we are waiting for the flusher to finish, but
3412                  * hold the current transaction open.
3413                  */
3414                 if (trans)
3415                         return -EAGAIN;
3416                 ret = wait_event_interruptible(space_info->wait,
3417                                                !space_info->flush);
3418                 /* Must have been interrupted, return */
3419                 if (ret)
3420                         return -EINTR;
3421
3422                 spin_lock(&space_info->lock);
3423         }
3424
3425         ret = -ENOSPC;
3426         unused = space_info->bytes_used + space_info->bytes_reserved +
3427                  space_info->bytes_pinned + space_info->bytes_readonly +
3428                  space_info->bytes_may_use;
3429
3430         /*
3431          * The idea here is that we've not already over-reserved the block group
3432          * then we can go ahead and save our reservation first and then start
3433          * flushing if we need to.  Otherwise if we've already overcommitted
3434          * lets start flushing stuff first and then come back and try to make
3435          * our reservation.
3436          */
3437         if (unused <= space_info->total_bytes) {
3438                 unused = space_info->total_bytes - unused;
3439                 if (unused >= num_bytes) {
3440                         space_info->bytes_reserved += orig_bytes;
3441                         ret = 0;
3442                 } else {
3443                         /*
3444                          * Ok set num_bytes to orig_bytes since we aren't
3445                          * overocmmitted, this way we only try and reclaim what
3446                          * we need.
3447                          */
3448                         num_bytes = orig_bytes;
3449                 }
3450         } else {
3451                 /*
3452                  * Ok we're over committed, set num_bytes to the overcommitted
3453                  * amount plus the amount of bytes that we need for this
3454                  * reservation.
3455                  */
3456                 num_bytes = unused - space_info->total_bytes +
3457                         (orig_bytes * (retries + 1));
3458         }
3459
3460         /*
3461          * Couldn't make our reservation, save our place so while we're trying
3462          * to reclaim space we can actually use it instead of somebody else
3463          * stealing it from us.
3464          */
3465         if (ret && flush) {
3466                 flushing = true;
3467                 space_info->flush = 1;
3468         }
3469
3470         spin_unlock(&space_info->lock);
3471
3472         if (!ret || !flush)
3473                 goto out;
3474
3475         /*
3476          * We do synchronous shrinking since we don't actually unreserve
3477          * metadata until after the IO is completed.
3478          */
3479         ret = shrink_delalloc(trans, root, num_bytes, 1);
3480         if (ret < 0)
3481                 goto out;
3482
3483         ret = 0;
3484
3485         /*
3486          * So if we were overcommitted it's possible that somebody else flushed
3487          * out enough space and we simply didn't have enough space to reclaim,
3488          * so go back around and try again.
3489          */
3490         if (retries < 2) {
3491                 retries++;
3492                 goto again;
3493         }
3494
3495         /*
3496          * Not enough space to be reclaimed, don't bother committing the
3497          * transaction.
3498          */
3499         spin_lock(&space_info->lock);
3500         if (space_info->bytes_pinned < orig_bytes)
3501                 ret = -ENOSPC;
3502         spin_unlock(&space_info->lock);
3503         if (ret)
3504                 goto out;
3505
3506         ret = -EAGAIN;
3507         if (trans)
3508                 goto out;
3509
3510         ret = -ENOSPC;
3511         if (committed)
3512                 goto out;
3513
3514         trans = btrfs_join_transaction(root);
3515         if (IS_ERR(trans))
3516                 goto out;
3517         ret = btrfs_commit_transaction(trans, root);
3518         if (!ret) {
3519                 trans = NULL;
3520                 committed = true;
3521                 goto again;
3522         }
3523
3524 out:
3525         if (flushing) {
3526                 spin_lock(&space_info->lock);
3527                 space_info->flush = 0;
3528                 wake_up_all(&space_info->wait);
3529                 spin_unlock(&space_info->lock);
3530         }
3531         return ret;
3532 }
3533
3534 static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
3535                                              struct btrfs_root *root)
3536 {
3537         struct btrfs_block_rsv *block_rsv;
3538         if (root->ref_cows)
3539                 block_rsv = trans->block_rsv;
3540         else
3541                 block_rsv = root->block_rsv;
3542
3543         if (!block_rsv)
3544                 block_rsv = &root->fs_info->empty_block_rsv;
3545
3546         return block_rsv;
3547 }
3548
3549 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3550                                u64 num_bytes)
3551 {
3552         int ret = -ENOSPC;
3553         spin_lock(&block_rsv->lock);
3554         if (block_rsv->reserved >= num_bytes) {
3555                 block_rsv->reserved -= num_bytes;
3556                 if (block_rsv->reserved < block_rsv->size)
3557                         block_rsv->full = 0;
3558                 ret = 0;
3559         }
3560         spin_unlock(&block_rsv->lock);
3561         return ret;
3562 }
3563
3564 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3565                                 u64 num_bytes, int update_size)
3566 {
3567         spin_lock(&block_rsv->lock);
3568         block_rsv->reserved += num_bytes;
3569         if (update_size)
3570                 block_rsv->size += num_bytes;
3571         else if (block_rsv->reserved >= block_rsv->size)
3572                 block_rsv->full = 1;
3573         spin_unlock(&block_rsv->lock);
3574 }
3575
3576 static void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
3577                                     struct btrfs_block_rsv *dest, u64 num_bytes)
3578 {
3579         struct btrfs_space_info *space_info = block_rsv->space_info;
3580
3581         spin_lock(&block_rsv->lock);
3582         if (num_bytes == (u64)-1)
3583                 num_bytes = block_rsv->size;
3584         block_rsv->size -= num_bytes;
3585         if (block_rsv->reserved >= block_rsv->size) {
3586                 num_bytes = block_rsv->reserved - block_rsv->size;
3587                 block_rsv->reserved = block_rsv->size;
3588                 block_rsv->full = 1;
3589         } else {
3590                 num_bytes = 0;
3591         }
3592         spin_unlock(&block_rsv->lock);
3593
3594         if (num_bytes > 0) {
3595                 if (dest) {
3596                         spin_lock(&dest->lock);
3597                         if (!dest->full) {
3598                                 u64 bytes_to_add;
3599
3600                                 bytes_to_add = dest->size - dest->reserved;
3601                                 bytes_to_add = min(num_bytes, bytes_to_add);
3602                                 dest->reserved += bytes_to_add;
3603                                 if (dest->reserved >= dest->size)
3604                                         dest->full = 1;
3605                                 num_bytes -= bytes_to_add;
3606                         }
3607                         spin_unlock(&dest->lock);
3608                 }
3609                 if (num_bytes) {
3610                         spin_lock(&space_info->lock);
3611                         space_info->bytes_reserved -= num_bytes;
3612                         space_info->reservation_progress++;
3613                         spin_unlock(&space_info->lock);
3614                 }
3615         }
3616 }
3617
3618 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3619                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3620 {
3621         int ret;
3622
3623         ret = block_rsv_use_bytes(src, num_bytes);
3624         if (ret)
3625                 return ret;
3626
3627         block_rsv_add_bytes(dst, num_bytes, 1);
3628         return 0;
3629 }
3630
3631 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3632 {
3633         memset(rsv, 0, sizeof(*rsv));
3634         spin_lock_init(&rsv->lock);
3635         atomic_set(&rsv->usage, 1);
3636         rsv->priority = 6;
3637         INIT_LIST_HEAD(&rsv->list);
3638 }
3639
3640 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
3641 {
3642         struct btrfs_block_rsv *block_rsv;
3643         struct btrfs_fs_info *fs_info = root->fs_info;
3644
3645         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
3646         if (!block_rsv)
3647                 return NULL;
3648
3649         btrfs_init_block_rsv(block_rsv);
3650         block_rsv->space_info = __find_space_info(fs_info,
3651                                                   BTRFS_BLOCK_GROUP_METADATA);
3652         return block_rsv;
3653 }
3654
3655 void btrfs_free_block_rsv(struct btrfs_root *root,
3656                           struct btrfs_block_rsv *rsv)
3657 {
3658         if (rsv && atomic_dec_and_test(&rsv->usage)) {
3659                 btrfs_block_rsv_release(root, rsv, (u64)-1);
3660                 if (!rsv->durable)
3661                         kfree(rsv);
3662         }
3663 }
3664
3665 /*
3666  * make the block_rsv struct be able to capture freed space.
3667  * the captured space will re-add to the the block_rsv struct
3668  * after transaction commit
3669  */
3670 void btrfs_add_durable_block_rsv(struct btrfs_fs_info *fs_info,
3671                                  struct btrfs_block_rsv *block_rsv)
3672 {
3673         block_rsv->durable = 1;
3674         mutex_lock(&fs_info->durable_block_rsv_mutex);
3675         list_add_tail(&block_rsv->list, &fs_info->durable_block_rsv_list);
3676         mutex_unlock(&fs_info->durable_block_rsv_mutex);
3677 }
3678
3679 int btrfs_block_rsv_add(struct btrfs_trans_handle *trans,
3680                         struct btrfs_root *root,
3681                         struct btrfs_block_rsv *block_rsv,
3682                         u64 num_bytes)
3683 {
3684         int ret;
3685
3686         if (num_bytes == 0)
3687                 return 0;
3688
3689         ret = reserve_metadata_bytes(trans, root, block_rsv, num_bytes, 1);
3690         if (!ret) {
3691                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
3692                 return 0;
3693         }
3694
3695         return ret;
3696 }
3697
3698 int btrfs_block_rsv_check(struct btrfs_trans_handle *trans,
3699                           struct btrfs_root *root,
3700                           struct btrfs_block_rsv *block_rsv,
3701                           u64 min_reserved, int min_factor)
3702 {
3703         u64 num_bytes = 0;
3704         int commit_trans = 0;
3705         int ret = -ENOSPC;
3706
3707         if (!block_rsv)
3708                 return 0;
3709
3710         spin_lock(&block_rsv->lock);
3711         if (min_factor > 0)
3712                 num_bytes = div_factor(block_rsv->size, min_factor);
3713         if (min_reserved > num_bytes)
3714                 num_bytes = min_reserved;
3715
3716         if (block_rsv->reserved >= num_bytes) {
3717                 ret = 0;
3718         } else {
3719                 num_bytes -= block_rsv->reserved;
3720                 if (block_rsv->durable &&
3721                     block_rsv->freed[0] + block_rsv->freed[1] >= num_bytes)
3722                         commit_trans = 1;
3723         }
3724         spin_unlock(&block_rsv->lock);
3725         if (!ret)
3726                 return 0;
3727
3728         if (block_rsv->refill_used) {
3729                 ret = reserve_metadata_bytes(trans, root, block_rsv,
3730                                              num_bytes, 0);
3731                 if (!ret) {
3732                         block_rsv_add_bytes(block_rsv, num_bytes, 0);
3733                         return 0;
3734                 }
3735         }
3736
3737         if (commit_trans) {
3738                 if (trans)
3739                         return -EAGAIN;
3740                 trans = btrfs_join_transaction(root);
3741                 BUG_ON(IS_ERR(trans));
3742                 ret = btrfs_commit_transaction(trans, root);
3743                 return 0;
3744         }
3745
3746         return -ENOSPC;
3747 }
3748
3749 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
3750                             struct btrfs_block_rsv *dst_rsv,
3751                             u64 num_bytes)
3752 {
3753         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3754 }
3755
3756 void btrfs_block_rsv_release(struct btrfs_root *root,
3757                              struct btrfs_block_rsv *block_rsv,
3758                              u64 num_bytes)
3759 {
3760         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3761         if (global_rsv->full || global_rsv == block_rsv ||
3762             block_rsv->space_info != global_rsv->space_info)
3763                 global_rsv = NULL;
3764         block_rsv_release_bytes(block_rsv, global_rsv, num_bytes);
3765 }
3766
3767 /*
3768  * helper to calculate size of global block reservation.
3769  * the desired value is sum of space used by extent tree,
3770  * checksum tree and root tree
3771  */
3772 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
3773 {
3774         struct btrfs_space_info *sinfo;
3775         u64 num_bytes;
3776         u64 meta_used;
3777         u64 data_used;
3778         int csum_size = btrfs_super_csum_size(&fs_info->super_copy);
3779
3780         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
3781         spin_lock(&sinfo->lock);
3782         data_used = sinfo->bytes_used;
3783         spin_unlock(&sinfo->lock);
3784
3785         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3786         spin_lock(&sinfo->lock);
3787         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
3788                 data_used = 0;
3789         meta_used = sinfo->bytes_used;
3790         spin_unlock(&sinfo->lock);
3791
3792         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
3793                     csum_size * 2;
3794         num_bytes += div64_u64(data_used + meta_used, 50);
3795
3796         if (num_bytes * 3 > meta_used)
3797                 num_bytes = div64_u64(meta_used, 3);
3798
3799         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
3800 }
3801
3802 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
3803 {
3804         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
3805         struct btrfs_space_info *sinfo = block_rsv->space_info;
3806         u64 num_bytes;
3807
3808         num_bytes = calc_global_metadata_size(fs_info);
3809
3810         spin_lock(&block_rsv->lock);
3811         spin_lock(&sinfo->lock);
3812
3813         block_rsv->size = num_bytes;
3814
3815         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
3816                     sinfo->bytes_reserved + sinfo->bytes_readonly +
3817                     sinfo->bytes_may_use;
3818
3819         if (sinfo->total_bytes > num_bytes) {
3820                 num_bytes = sinfo->total_bytes - num_bytes;
3821                 block_rsv->reserved += num_bytes;
3822                 sinfo->bytes_reserved += num_bytes;
3823         }
3824
3825         if (block_rsv->reserved >= block_rsv->size) {
3826                 num_bytes = block_rsv->reserved - block_rsv->size;
3827                 sinfo->bytes_reserved -= num_bytes;
3828                 sinfo->reservation_progress++;
3829                 block_rsv->reserved = block_rsv->size;
3830                 block_rsv->full = 1;
3831         }
3832
3833         spin_unlock(&sinfo->lock);
3834         spin_unlock(&block_rsv->lock);
3835 }
3836
3837 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
3838 {
3839         struct btrfs_space_info *space_info;
3840
3841         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3842         fs_info->chunk_block_rsv.space_info = space_info;
3843         fs_info->chunk_block_rsv.priority = 10;
3844
3845         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3846         fs_info->global_block_rsv.space_info = space_info;
3847         fs_info->global_block_rsv.priority = 10;
3848         fs_info->global_block_rsv.refill_used = 1;
3849         fs_info->delalloc_block_rsv.space_info = space_info;
3850         fs_info->trans_block_rsv.space_info = space_info;
3851         fs_info->empty_block_rsv.space_info = space_info;
3852         fs_info->empty_block_rsv.priority = 10;
3853
3854         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
3855         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
3856         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
3857         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
3858         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
3859
3860         btrfs_add_durable_block_rsv(fs_info, &fs_info->global_block_rsv);
3861
3862         btrfs_add_durable_block_rsv(fs_info, &fs_info->delalloc_block_rsv);
3863
3864         update_global_block_rsv(fs_info);
3865 }
3866
3867 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
3868 {
3869         block_rsv_release_bytes(&fs_info->global_block_rsv, NULL, (u64)-1);
3870         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
3871         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
3872         WARN_ON(fs_info->trans_block_rsv.size > 0);
3873         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
3874         WARN_ON(fs_info->chunk_block_rsv.size > 0);
3875         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
3876 }
3877
3878 int btrfs_truncate_reserve_metadata(struct btrfs_trans_handle *trans,
3879                                     struct btrfs_root *root,
3880                                     struct btrfs_block_rsv *rsv)
3881 {
3882         struct btrfs_block_rsv *trans_rsv = &root->fs_info->trans_block_rsv;
3883         u64 num_bytes;
3884         int ret;
3885
3886         /*
3887          * Truncate should be freeing data, but give us 2 items just in case it
3888          * needs to use some space.  We may want to be smarter about this in the
3889          * future.
3890          */
3891         num_bytes = btrfs_calc_trans_metadata_size(root, 2);
3892
3893         /* We already have enough bytes, just return */
3894         if (rsv->reserved >= num_bytes)
3895                 return 0;
3896
3897         num_bytes -= rsv->reserved;
3898
3899         /*
3900          * You should have reserved enough space before hand to do this, so this
3901          * should not fail.
3902          */
3903         ret = block_rsv_migrate_bytes(trans_rsv, rsv, num_bytes);
3904         BUG_ON(ret);
3905
3906         return 0;
3907 }
3908
3909 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
3910                                   struct btrfs_root *root)
3911 {
3912         if (!trans->bytes_reserved)
3913                 return;
3914
3915         BUG_ON(trans->block_rsv != &root->fs_info->trans_block_rsv);
3916         btrfs_block_rsv_release(root, trans->block_rsv,
3917                                 trans->bytes_reserved);
3918         trans->bytes_reserved = 0;
3919 }
3920
3921 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
3922                                   struct inode *inode)
3923 {
3924         struct btrfs_root *root = BTRFS_I(inode)->root;
3925         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3926         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
3927
3928         /*
3929          * We need to hold space in order to delete our orphan item once we've
3930          * added it, so this takes the reservation so we can release it later
3931          * when we are truly done with the orphan item.
3932          */
3933         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
3934         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3935 }
3936
3937 void btrfs_orphan_release_metadata(struct inode *inode)
3938 {
3939         struct btrfs_root *root = BTRFS_I(inode)->root;
3940         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
3941         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
3942 }
3943
3944 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
3945                                 struct btrfs_pending_snapshot *pending)
3946 {
3947         struct btrfs_root *root = pending->root;
3948         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3949         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
3950         /*
3951          * two for root back/forward refs, two for directory entries
3952          * and one for root of the snapshot.
3953          */
3954         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3955         dst_rsv->space_info = src_rsv->space_info;
3956         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3957 }
3958
3959 static unsigned drop_outstanding_extent(struct inode *inode)
3960 {
3961         unsigned dropped_extents = 0;
3962
3963         spin_lock(&BTRFS_I(inode)->lock);
3964         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
3965         BTRFS_I(inode)->outstanding_extents--;
3966
3967         /*
3968          * If we have more or the same amount of outsanding extents than we have
3969          * reserved then we need to leave the reserved extents count alone.
3970          */
3971         if (BTRFS_I(inode)->outstanding_extents >=
3972             BTRFS_I(inode)->reserved_extents)
3973                 goto out;
3974
3975         dropped_extents = BTRFS_I(inode)->reserved_extents -
3976                 BTRFS_I(inode)->outstanding_extents;
3977         BTRFS_I(inode)->reserved_extents -= dropped_extents;
3978 out:
3979         spin_unlock(&BTRFS_I(inode)->lock);
3980         return dropped_extents;
3981 }
3982
3983 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes)
3984 {
3985         return num_bytes >>= 3;
3986 }
3987
3988 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
3989 {
3990         struct btrfs_root *root = BTRFS_I(inode)->root;
3991         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
3992         u64 to_reserve = 0;
3993         unsigned nr_extents = 0;
3994         int ret;
3995
3996         if (btrfs_transaction_in_commit(root->fs_info))
3997                 schedule_timeout(1);
3998
3999         num_bytes = ALIGN(num_bytes, root->sectorsize);
4000
4001         spin_lock(&BTRFS_I(inode)->lock);
4002         BTRFS_I(inode)->outstanding_extents++;
4003
4004         if (BTRFS_I(inode)->outstanding_extents >
4005             BTRFS_I(inode)->reserved_extents) {
4006                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4007                         BTRFS_I(inode)->reserved_extents;
4008                 BTRFS_I(inode)->reserved_extents += nr_extents;
4009
4010                 to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4011         }
4012         spin_unlock(&BTRFS_I(inode)->lock);
4013
4014         to_reserve += calc_csum_metadata_size(inode, num_bytes);
4015         ret = reserve_metadata_bytes(NULL, root, block_rsv, to_reserve, 1);
4016         if (ret) {
4017                 unsigned dropped;
4018                 /*
4019                  * We don't need the return value since our reservation failed,
4020                  * we just need to clean up our counter.
4021                  */
4022                 dropped = drop_outstanding_extent(inode);
4023                 WARN_ON(dropped > 1);
4024                 return ret;
4025         }
4026
4027         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4028
4029         return 0;
4030 }
4031
4032 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4033 {
4034         struct btrfs_root *root = BTRFS_I(inode)->root;
4035         u64 to_free = 0;
4036         unsigned dropped;
4037
4038         num_bytes = ALIGN(num_bytes, root->sectorsize);
4039         dropped = drop_outstanding_extent(inode);
4040
4041         to_free = calc_csum_metadata_size(inode, num_bytes);
4042         if (dropped > 0)
4043                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4044
4045         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4046                                 to_free);
4047 }
4048
4049 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4050 {
4051         int ret;
4052
4053         ret = btrfs_check_data_free_space(inode, num_bytes);
4054         if (ret)
4055                 return ret;
4056
4057         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4058         if (ret) {
4059                 btrfs_free_reserved_data_space(inode, num_bytes);
4060                 return ret;
4061         }
4062
4063         return 0;
4064 }
4065
4066 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4067 {
4068         btrfs_delalloc_release_metadata(inode, num_bytes);
4069         btrfs_free_reserved_data_space(inode, num_bytes);
4070 }
4071
4072 static int update_block_group(struct btrfs_trans_handle *trans,
4073                               struct btrfs_root *root,
4074                               u64 bytenr, u64 num_bytes, int alloc)
4075 {
4076         struct btrfs_block_group_cache *cache = NULL;
4077         struct btrfs_fs_info *info = root->fs_info;
4078         u64 total = num_bytes;
4079         u64 old_val;
4080         u64 byte_in_group;
4081         int factor;
4082
4083         /* block accounting for super block */
4084         spin_lock(&info->delalloc_lock);
4085         old_val = btrfs_super_bytes_used(&info->super_copy);
4086         if (alloc)
4087                 old_val += num_bytes;
4088         else
4089                 old_val -= num_bytes;
4090         btrfs_set_super_bytes_used(&info->super_copy, old_val);
4091         spin_unlock(&info->delalloc_lock);
4092
4093         while (total) {
4094                 cache = btrfs_lookup_block_group(info, bytenr);
4095                 if (!cache)
4096                         return -1;
4097                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4098                                     BTRFS_BLOCK_GROUP_RAID1 |
4099                                     BTRFS_BLOCK_GROUP_RAID10))
4100                         factor = 2;
4101                 else
4102                         factor = 1;
4103                 /*
4104                  * If this block group has free space cache written out, we
4105                  * need to make sure to load it if we are removing space.  This
4106                  * is because we need the unpinning stage to actually add the
4107                  * space back to the block group, otherwise we will leak space.
4108                  */
4109                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4110                         cache_block_group(cache, trans, NULL, 1);
4111
4112                 byte_in_group = bytenr - cache->key.objectid;
4113                 WARN_ON(byte_in_group > cache->key.offset);
4114
4115                 spin_lock(&cache->space_info->lock);
4116                 spin_lock(&cache->lock);
4117
4118                 if (btrfs_super_cache_generation(&info->super_copy) != 0 &&
4119                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4120                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4121
4122                 cache->dirty = 1;
4123                 old_val = btrfs_block_group_used(&cache->item);
4124                 num_bytes = min(total, cache->key.offset - byte_in_group);
4125                 if (alloc) {
4126                         old_val += num_bytes;
4127                         btrfs_set_block_group_used(&cache->item, old_val);
4128                         cache->reserved -= num_bytes;
4129                         cache->space_info->bytes_reserved -= num_bytes;
4130                         cache->space_info->reservation_progress++;
4131                         cache->space_info->bytes_used += num_bytes;
4132                         cache->space_info->disk_used += num_bytes * factor;
4133                         spin_unlock(&cache->lock);
4134                         spin_unlock(&cache->space_info->lock);
4135                 } else {
4136                         old_val -= num_bytes;
4137                         btrfs_set_block_group_used(&cache->item, old_val);
4138                         cache->pinned += num_bytes;
4139                         cache->space_info->bytes_pinned += num_bytes;
4140                         cache->space_info->bytes_used -= num_bytes;
4141                         cache->space_info->disk_used -= num_bytes * factor;
4142                         spin_unlock(&cache->lock);
4143                         spin_unlock(&cache->space_info->lock);
4144
4145                         set_extent_dirty(info->pinned_extents,
4146                                          bytenr, bytenr + num_bytes - 1,
4147                                          GFP_NOFS | __GFP_NOFAIL);
4148                 }
4149                 btrfs_put_block_group(cache);
4150                 total -= num_bytes;
4151                 bytenr += num_bytes;
4152         }
4153         return 0;
4154 }
4155
4156 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4157 {
4158         struct btrfs_block_group_cache *cache;
4159         u64 bytenr;
4160
4161         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4162         if (!cache)
4163                 return 0;
4164
4165         bytenr = cache->key.objectid;
4166         btrfs_put_block_group(cache);
4167
4168         return bytenr;
4169 }
4170
4171 static int pin_down_extent(struct btrfs_root *root,
4172                            struct btrfs_block_group_cache *cache,
4173                            u64 bytenr, u64 num_bytes, int reserved)
4174 {
4175         spin_lock(&cache->space_info->lock);
4176         spin_lock(&cache->lock);
4177         cache->pinned += num_bytes;
4178         cache->space_info->bytes_pinned += num_bytes;
4179         if (reserved) {
4180                 cache->reserved -= num_bytes;
4181                 cache->space_info->bytes_reserved -= num_bytes;
4182                 cache->space_info->reservation_progress++;
4183         }
4184         spin_unlock(&cache->lock);
4185         spin_unlock(&cache->space_info->lock);
4186
4187         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4188                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4189         return 0;
4190 }
4191
4192 /*
4193  * this function must be called within transaction
4194  */
4195 int btrfs_pin_extent(struct btrfs_root *root,
4196                      u64 bytenr, u64 num_bytes, int reserved)
4197 {
4198         struct btrfs_block_group_cache *cache;
4199
4200         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4201         BUG_ON(!cache);
4202
4203         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4204
4205         btrfs_put_block_group(cache);
4206         return 0;
4207 }
4208
4209 /*
4210  * update size of reserved extents. this function may return -EAGAIN
4211  * if 'reserve' is true or 'sinfo' is false.
4212  */
4213 int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4214                                 u64 num_bytes, int reserve, int sinfo)
4215 {
4216         int ret = 0;
4217         if (sinfo) {
4218                 struct btrfs_space_info *space_info = cache->space_info;
4219                 spin_lock(&space_info->lock);
4220                 spin_lock(&cache->lock);
4221                 if (reserve) {
4222                         if (cache->ro) {
4223                                 ret = -EAGAIN;
4224                         } else {
4225                                 cache->reserved += num_bytes;
4226                                 space_info->bytes_reserved += num_bytes;
4227                         }
4228                 } else {
4229                         if (cache->ro)
4230                                 space_info->bytes_readonly += num_bytes;
4231                         cache->reserved -= num_bytes;
4232                         space_info->bytes_reserved -= num_bytes;
4233                         space_info->reservation_progress++;
4234                 }
4235                 spin_unlock(&cache->lock);
4236                 spin_unlock(&space_info->lock);
4237         } else {
4238                 spin_lock(&cache->lock);
4239                 if (cache->ro) {
4240                         ret = -EAGAIN;
4241                 } else {
4242                         if (reserve)
4243                                 cache->reserved += num_bytes;
4244                         else
4245                                 cache->reserved -= num_bytes;
4246                 }
4247                 spin_unlock(&cache->lock);
4248         }
4249         return ret;
4250 }
4251
4252 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4253                                 struct btrfs_root *root)
4254 {
4255         struct btrfs_fs_info *fs_info = root->fs_info;
4256         struct btrfs_caching_control *next;
4257         struct btrfs_caching_control *caching_ctl;
4258         struct btrfs_block_group_cache *cache;
4259
4260         down_write(&fs_info->extent_commit_sem);
4261
4262         list_for_each_entry_safe(caching_ctl, next,
4263                                  &fs_info->caching_block_groups, list) {
4264                 cache = caching_ctl->block_group;
4265                 if (block_group_cache_done(cache)) {
4266                         cache->last_byte_to_unpin = (u64)-1;
4267                         list_del_init(&caching_ctl->list);
4268                         put_caching_control(caching_ctl);
4269                 } else {
4270                         cache->last_byte_to_unpin = caching_ctl->progress;
4271                 }
4272         }
4273
4274         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4275                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4276         else
4277                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4278
4279         up_write(&fs_info->extent_commit_sem);
4280
4281         update_global_block_rsv(fs_info);
4282         return 0;
4283 }
4284
4285 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4286 {
4287         struct btrfs_fs_info *fs_info = root->fs_info;
4288         struct btrfs_block_group_cache *cache = NULL;
4289         u64 len;
4290
4291         while (start <= end) {
4292                 if (!cache ||
4293                     start >= cache->key.objectid + cache->key.offset) {
4294                         if (cache)
4295                                 btrfs_put_block_group(cache);
4296                         cache = btrfs_lookup_block_group(fs_info, start);
4297                         BUG_ON(!cache);
4298                 }
4299
4300                 len = cache->key.objectid + cache->key.offset - start;
4301                 len = min(len, end + 1 - start);
4302
4303                 if (start < cache->last_byte_to_unpin) {
4304                         len = min(len, cache->last_byte_to_unpin - start);
4305                         btrfs_add_free_space(cache, start, len);
4306                 }
4307
4308                 start += len;
4309
4310                 spin_lock(&cache->space_info->lock);
4311                 spin_lock(&cache->lock);
4312                 cache->pinned -= len;
4313                 cache->space_info->bytes_pinned -= len;
4314                 if (cache->ro) {
4315                         cache->space_info->bytes_readonly += len;
4316                 } else if (cache->reserved_pinned > 0) {
4317                         len = min(len, cache->reserved_pinned);
4318                         cache->reserved_pinned -= len;
4319                         cache->space_info->bytes_reserved += len;
4320                 }
4321                 spin_unlock(&cache->lock);
4322                 spin_unlock(&cache->space_info->lock);
4323         }
4324
4325         if (cache)
4326                 btrfs_put_block_group(cache);
4327         return 0;
4328 }
4329
4330 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4331                                struct btrfs_root *root)
4332 {
4333         struct btrfs_fs_info *fs_info = root->fs_info;
4334         struct extent_io_tree *unpin;
4335         struct btrfs_block_rsv *block_rsv;
4336         struct btrfs_block_rsv *next_rsv;
4337         u64 start;
4338         u64 end;
4339         int idx;
4340         int ret;
4341
4342         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4343                 unpin = &fs_info->freed_extents[1];
4344         else
4345                 unpin = &fs_info->freed_extents[0];
4346
4347         while (1) {
4348                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4349                                             EXTENT_DIRTY);
4350                 if (ret)
4351                         break;
4352
4353                 if (btrfs_test_opt(root, DISCARD))
4354                         ret = btrfs_discard_extent(root, start,
4355                                                    end + 1 - start, NULL);
4356
4357                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4358                 unpin_extent_range(root, start, end);
4359                 cond_resched();
4360         }
4361
4362         mutex_lock(&fs_info->durable_block_rsv_mutex);
4363         list_for_each_entry_safe(block_rsv, next_rsv,
4364                                  &fs_info->durable_block_rsv_list, list) {
4365
4366                 idx = trans->transid & 0x1;
4367                 if (block_rsv->freed[idx] > 0) {
4368                         block_rsv_add_bytes(block_rsv,
4369                                             block_rsv->freed[idx], 0);
4370                         block_rsv->freed[idx] = 0;
4371                 }
4372                 if (atomic_read(&block_rsv->usage) == 0) {
4373                         btrfs_block_rsv_release(root, block_rsv, (u64)-1);
4374
4375                         if (block_rsv->freed[0] == 0 &&
4376                             block_rsv->freed[1] == 0) {
4377                                 list_del_init(&block_rsv->list);
4378                                 kfree(block_rsv);
4379                         }
4380                 } else {
4381                         btrfs_block_rsv_release(root, block_rsv, 0);
4382                 }
4383         }
4384         mutex_unlock(&fs_info->durable_block_rsv_mutex);
4385
4386         return 0;
4387 }
4388
4389 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4390                                 struct btrfs_root *root,
4391                                 u64 bytenr, u64 num_bytes, u64 parent,
4392                                 u64 root_objectid, u64 owner_objectid,
4393                                 u64 owner_offset, int refs_to_drop,
4394                                 struct btrfs_delayed_extent_op *extent_op)
4395 {
4396         struct btrfs_key key;
4397         struct btrfs_path *path;
4398         struct btrfs_fs_info *info = root->fs_info;
4399         struct btrfs_root *extent_root = info->extent_root;
4400         struct extent_buffer *leaf;
4401         struct btrfs_extent_item *ei;
4402         struct btrfs_extent_inline_ref *iref;
4403         int ret;
4404         int is_data;
4405         int extent_slot = 0;
4406         int found_extent = 0;
4407         int num_to_del = 1;
4408         u32 item_size;
4409         u64 refs;
4410
4411         path = btrfs_alloc_path();
4412         if (!path)
4413                 return -ENOMEM;
4414
4415         path->reada = 1;
4416         path->leave_spinning = 1;
4417
4418         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4419         BUG_ON(!is_data && refs_to_drop != 1);
4420
4421         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4422                                     bytenr, num_bytes, parent,
4423                                     root_objectid, owner_objectid,
4424                                     owner_offset);
4425         if (ret == 0) {
4426                 extent_slot = path->slots[0];
4427                 while (extent_slot >= 0) {
4428                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4429                                               extent_slot);
4430                         if (key.objectid != bytenr)
4431                                 break;
4432                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4433                             key.offset == num_bytes) {
4434                                 found_extent = 1;
4435                                 break;
4436                         }
4437                         if (path->slots[0] - extent_slot > 5)
4438                                 break;
4439                         extent_slot--;
4440                 }
4441 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4442                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4443                 if (found_extent && item_size < sizeof(*ei))
4444                         found_extent = 0;
4445 #endif
4446                 if (!found_extent) {
4447                         BUG_ON(iref);
4448                         ret = remove_extent_backref(trans, extent_root, path,
4449                                                     NULL, refs_to_drop,
4450                                                     is_data);
4451                         BUG_ON(ret);
4452                         btrfs_release_path(path);
4453                         path->leave_spinning = 1;
4454
4455                         key.objectid = bytenr;
4456                         key.type = BTRFS_EXTENT_ITEM_KEY;
4457                         key.offset = num_bytes;
4458
4459                         ret = btrfs_search_slot(trans, extent_root,
4460                                                 &key, path, -1, 1);
4461                         if (ret) {
4462                                 printk(KERN_ERR "umm, got %d back from search"
4463                                        ", was looking for %llu\n", ret,
4464                                        (unsigned long long)bytenr);
4465                                 btrfs_print_leaf(extent_root, path->nodes[0]);
4466                         }
4467                         BUG_ON(ret);
4468                         extent_slot = path->slots[0];
4469                 }
4470         } else {
4471                 btrfs_print_leaf(extent_root, path->nodes[0]);
4472                 WARN_ON(1);
4473                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4474                        "parent %llu root %llu  owner %llu offset %llu\n",
4475                        (unsigned long long)bytenr,
4476                        (unsigned long long)parent,
4477                        (unsigned long long)root_objectid,
4478                        (unsigned long long)owner_objectid,
4479                        (unsigned long long)owner_offset);
4480         }
4481
4482         leaf = path->nodes[0];
4483         item_size = btrfs_item_size_nr(leaf, extent_slot);
4484 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4485         if (item_size < sizeof(*ei)) {
4486                 BUG_ON(found_extent || extent_slot != path->slots[0]);
4487                 ret = convert_extent_item_v0(trans, extent_root, path,
4488                                              owner_objectid, 0);
4489                 BUG_ON(ret < 0);
4490
4491                 btrfs_release_path(path);
4492                 path->leave_spinning = 1;
4493
4494                 key.objectid = bytenr;
4495                 key.type = BTRFS_EXTENT_ITEM_KEY;
4496                 key.offset = num_bytes;
4497
4498                 ret = btrfs_search_slot(trans, extent_root, &key, path,
4499                                         -1, 1);
4500                 if (ret) {
4501                         printk(KERN_ERR "umm, got %d back from search"
4502                                ", was looking for %llu\n", ret,
4503                                (unsigned long long)bytenr);
4504                         btrfs_print_leaf(extent_root, path->nodes[0]);
4505                 }
4506                 BUG_ON(ret);
4507                 extent_slot = path->slots[0];
4508                 leaf = path->nodes[0];
4509                 item_size = btrfs_item_size_nr(leaf, extent_slot);
4510         }
4511 #endif
4512         BUG_ON(item_size < sizeof(*ei));
4513         ei = btrfs_item_ptr(leaf, extent_slot,
4514                             struct btrfs_extent_item);
4515         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4516                 struct btrfs_tree_block_info *bi;
4517                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
4518                 bi = (struct btrfs_tree_block_info *)(ei + 1);
4519                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
4520         }
4521
4522         refs = btrfs_extent_refs(leaf, ei);
4523         BUG_ON(refs < refs_to_drop);
4524         refs -= refs_to_drop;
4525
4526         if (refs > 0) {
4527                 if (extent_op)
4528                         __run_delayed_extent_op(extent_op, leaf, ei);
4529                 /*
4530                  * In the case of inline back ref, reference count will
4531                  * be updated by remove_extent_backref
4532                  */
4533                 if (iref) {
4534                         BUG_ON(!found_extent);
4535                 } else {
4536                         btrfs_set_extent_refs(leaf, ei, refs);
4537                         btrfs_mark_buffer_dirty(leaf);
4538                 }
4539                 if (found_extent) {
4540                         ret = remove_extent_backref(trans, extent_root, path,
4541                                                     iref, refs_to_drop,
4542                                                     is_data);
4543                         BUG_ON(ret);
4544                 }
4545         } else {
4546                 if (found_extent) {
4547                         BUG_ON(is_data && refs_to_drop !=
4548                                extent_data_ref_count(root, path, iref));
4549                         if (iref) {
4550                                 BUG_ON(path->slots[0] != extent_slot);
4551                         } else {
4552                                 BUG_ON(path->slots[0] != extent_slot + 1);
4553                                 path->slots[0] = extent_slot;
4554                                 num_to_del = 2;
4555                         }
4556                 }
4557
4558                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
4559                                       num_to_del);
4560                 BUG_ON(ret);
4561                 btrfs_release_path(path);
4562
4563                 if (is_data) {
4564                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
4565                         BUG_ON(ret);
4566                 } else {
4567                         invalidate_mapping_pages(info->btree_inode->i_mapping,
4568                              bytenr >> PAGE_CACHE_SHIFT,
4569                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
4570                 }
4571
4572                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
4573                 BUG_ON(ret);
4574         }
4575         btrfs_free_path(path);
4576         return ret;
4577 }
4578
4579 /*
4580  * when we free an block, it is possible (and likely) that we free the last
4581  * delayed ref for that extent as well.  This searches the delayed ref tree for
4582  * a given extent, and if there are no other delayed refs to be processed, it
4583  * removes it from the tree.
4584  */
4585 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
4586                                       struct btrfs_root *root, u64 bytenr)
4587 {
4588         struct btrfs_delayed_ref_head *head;
4589         struct btrfs_delayed_ref_root *delayed_refs;
4590         struct btrfs_delayed_ref_node *ref;
4591         struct rb_node *node;
4592         int ret = 0;
4593
4594         delayed_refs = &trans->transaction->delayed_refs;
4595         spin_lock(&delayed_refs->lock);
4596         head = btrfs_find_delayed_ref_head(trans, bytenr);
4597         if (!head)
4598                 goto out;
4599
4600         node = rb_prev(&head->node.rb_node);
4601         if (!node)
4602                 goto out;
4603
4604         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
4605
4606         /* there are still entries for this ref, we can't drop it */
4607         if (ref->bytenr == bytenr)
4608                 goto out;
4609
4610         if (head->extent_op) {
4611                 if (!head->must_insert_reserved)
4612                         goto out;
4613                 kfree(head->extent_op);
4614                 head->extent_op = NULL;
4615         }
4616
4617         /*
4618          * waiting for the lock here would deadlock.  If someone else has it
4619          * locked they are already in the process of dropping it anyway
4620          */
4621         if (!mutex_trylock(&head->mutex))
4622                 goto out;
4623
4624         /*
4625          * at this point we have a head with no other entries.  Go
4626          * ahead and process it.
4627          */
4628         head->node.in_tree = 0;
4629         rb_erase(&head->node.rb_node, &delayed_refs->root);
4630
4631         delayed_refs->num_entries--;
4632
4633         /*
4634          * we don't take a ref on the node because we're removing it from the
4635          * tree, so we just steal the ref the tree was holding.
4636          */
4637         delayed_refs->num_heads--;
4638         if (list_empty(&head->cluster))
4639                 delayed_refs->num_heads_ready--;
4640
4641         list_del_init(&head->cluster);
4642         spin_unlock(&delayed_refs->lock);
4643
4644         BUG_ON(head->extent_op);
4645         if (head->must_insert_reserved)
4646                 ret = 1;
4647
4648         mutex_unlock(&head->mutex);
4649         btrfs_put_delayed_ref(&head->node);
4650         return ret;
4651 out:
4652         spin_unlock(&delayed_refs->lock);
4653         return 0;
4654 }
4655
4656 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
4657                            struct btrfs_root *root,
4658                            struct extent_buffer *buf,
4659                            u64 parent, int last_ref)
4660 {
4661         struct btrfs_block_rsv *block_rsv;
4662         struct btrfs_block_group_cache *cache = NULL;
4663         int ret;
4664
4665         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4666                 ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
4667                                                 parent, root->root_key.objectid,
4668                                                 btrfs_header_level(buf),
4669                                                 BTRFS_DROP_DELAYED_REF, NULL);
4670                 BUG_ON(ret);
4671         }
4672
4673         if (!last_ref)
4674                 return;
4675
4676         block_rsv = get_block_rsv(trans, root);
4677         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
4678         if (block_rsv->space_info != cache->space_info)
4679                 goto out;
4680
4681         if (btrfs_header_generation(buf) == trans->transid) {
4682                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4683                         ret = check_ref_cleanup(trans, root, buf->start);
4684                         if (!ret)
4685                                 goto pin;
4686                 }
4687
4688                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
4689                         pin_down_extent(root, cache, buf->start, buf->len, 1);
4690                         goto pin;
4691                 }
4692
4693                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
4694
4695                 btrfs_add_free_space(cache, buf->start, buf->len);
4696                 ret = btrfs_update_reserved_bytes(cache, buf->len, 0, 0);
4697                 if (ret == -EAGAIN) {
4698                         /* block group became read-only */
4699                         btrfs_update_reserved_bytes(cache, buf->len, 0, 1);
4700                         goto out;
4701                 }
4702
4703                 ret = 1;
4704                 spin_lock(&block_rsv->lock);
4705                 if (block_rsv->reserved < block_rsv->size) {
4706                         block_rsv->reserved += buf->len;
4707                         ret = 0;
4708                 }
4709                 spin_unlock(&block_rsv->lock);
4710
4711                 if (ret) {
4712                         spin_lock(&cache->space_info->lock);
4713                         cache->space_info->bytes_reserved -= buf->len;
4714                         cache->space_info->reservation_progress++;
4715                         spin_unlock(&cache->space_info->lock);
4716                 }
4717                 goto out;
4718         }
4719 pin:
4720         if (block_rsv->durable && !cache->ro) {
4721                 ret = 0;
4722                 spin_lock(&cache->lock);
4723                 if (!cache->ro) {
4724                         cache->reserved_pinned += buf->len;
4725                         ret = 1;
4726                 }
4727                 spin_unlock(&cache->lock);
4728
4729                 if (ret) {
4730                         spin_lock(&block_rsv->lock);
4731                         block_rsv->freed[trans->transid & 0x1] += buf->len;
4732                         spin_unlock(&block_rsv->lock);
4733                 }
4734         }
4735 out:
4736         /*
4737          * Deleting the buffer, clear the corrupt flag since it doesn't matter
4738          * anymore.
4739          */
4740         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
4741         btrfs_put_block_group(cache);
4742 }
4743
4744 int btrfs_free_extent(struct btrfs_trans_handle *trans,
4745                       struct btrfs_root *root,
4746                       u64 bytenr, u64 num_bytes, u64 parent,
4747                       u64 root_objectid, u64 owner, u64 offset)
4748 {
4749         int ret;
4750
4751         /*
4752          * tree log blocks never actually go into the extent allocation
4753          * tree, just update pinning info and exit early.
4754          */
4755         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
4756                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
4757                 /* unlocks the pinned mutex */
4758                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
4759                 ret = 0;
4760         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
4761                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
4762                                         parent, root_objectid, (int)owner,
4763                                         BTRFS_DROP_DELAYED_REF, NULL);
4764                 BUG_ON(ret);
4765         } else {
4766                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
4767                                         parent, root_objectid, owner,
4768                                         offset, BTRFS_DROP_DELAYED_REF, NULL);
4769                 BUG_ON(ret);
4770         }
4771         return ret;
4772 }
4773
4774 static u64 stripe_align(struct btrfs_root *root, u64 val)
4775 {
4776         u64 mask = ((u64)root->stripesize - 1);
4777         u64 ret = (val + mask) & ~mask;
4778         return ret;
4779 }
4780
4781 /*
4782  * when we wait for progress in the block group caching, its because
4783  * our allocation attempt failed at least once.  So, we must sleep
4784  * and let some progress happen before we try again.
4785  *
4786  * This function will sleep at least once waiting for new free space to
4787  * show up, and then it will check the block group free space numbers
4788  * for our min num_bytes.  Another option is to have it go ahead
4789  * and look in the rbtree for a free extent of a given size, but this
4790  * is a good start.
4791  */
4792 static noinline int
4793 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
4794                                 u64 num_bytes)
4795 {
4796         struct btrfs_caching_control *caching_ctl;
4797         DEFINE_WAIT(wait);
4798
4799         caching_ctl = get_caching_control(cache);
4800         if (!caching_ctl)
4801                 return 0;
4802
4803         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
4804                    (cache->free_space_ctl->free_space >= num_bytes));
4805
4806         put_caching_control(caching_ctl);
4807         return 0;
4808 }
4809
4810 static noinline int
4811 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
4812 {
4813         struct btrfs_caching_control *caching_ctl;
4814         DEFINE_WAIT(wait);
4815
4816         caching_ctl = get_caching_control(cache);
4817         if (!caching_ctl)
4818                 return 0;
4819
4820         wait_event(caching_ctl->wait, block_group_cache_done(cache));
4821
4822         put_caching_control(caching_ctl);
4823         return 0;
4824 }
4825
4826 static int get_block_group_index(struct btrfs_block_group_cache *cache)
4827 {
4828         int index;
4829         if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
4830                 index = 0;
4831         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
4832                 index = 1;
4833         else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
4834                 index = 2;
4835         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
4836                 index = 3;
4837         else
4838                 index = 4;
4839         return index;
4840 }
4841
4842 enum btrfs_loop_type {
4843         LOOP_FIND_IDEAL = 0,
4844         LOOP_CACHING_NOWAIT = 1,
4845         LOOP_CACHING_WAIT = 2,
4846         LOOP_ALLOC_CHUNK = 3,
4847         LOOP_NO_EMPTY_SIZE = 4,
4848 };
4849
4850 /*
4851  * walks the btree of allocated extents and find a hole of a given size.
4852  * The key ins is changed to record the hole:
4853  * ins->objectid == block start
4854  * ins->flags = BTRFS_EXTENT_ITEM_KEY
4855  * ins->offset == number of blocks
4856  * Any available blocks before search_start are skipped.
4857  */
4858 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
4859                                      struct btrfs_root *orig_root,
4860                                      u64 num_bytes, u64 empty_size,
4861                                      u64 search_start, u64 search_end,
4862                                      u64 hint_byte, struct btrfs_key *ins,
4863                                      u64 data)
4864 {
4865         int ret = 0;
4866         struct btrfs_root *root = orig_root->fs_info->extent_root;
4867         struct btrfs_free_cluster *last_ptr = NULL;
4868         struct btrfs_block_group_cache *block_group = NULL;
4869         int empty_cluster = 2 * 1024 * 1024;
4870         int allowed_chunk_alloc = 0;
4871         int done_chunk_alloc = 0;
4872         struct btrfs_space_info *space_info;
4873         int last_ptr_loop = 0;
4874         int loop = 0;
4875         int index = 0;
4876         bool found_uncached_bg = false;
4877         bool failed_cluster_refill = false;
4878         bool failed_alloc = false;
4879         bool use_cluster = true;
4880         u64 ideal_cache_percent = 0;
4881         u64 ideal_cache_offset = 0;
4882
4883         WARN_ON(num_bytes < root->sectorsize);
4884         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
4885         ins->objectid = 0;
4886         ins->offset = 0;
4887
4888         space_info = __find_space_info(root->fs_info, data);
4889         if (!space_info) {
4890                 printk(KERN_ERR "No space info for %llu\n", data);
4891                 return -ENOSPC;
4892         }
4893
4894         /*
4895          * If the space info is for both data and metadata it means we have a
4896          * small filesystem and we can't use the clustering stuff.
4897          */
4898         if (btrfs_mixed_space_info(space_info))
4899                 use_cluster = false;
4900
4901         if (orig_root->ref_cows || empty_size)
4902                 allowed_chunk_alloc = 1;
4903
4904         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
4905                 last_ptr = &root->fs_info->meta_alloc_cluster;
4906                 if (!btrfs_test_opt(root, SSD))
4907                         empty_cluster = 64 * 1024;
4908         }
4909
4910         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
4911             btrfs_test_opt(root, SSD)) {
4912                 last_ptr = &root->fs_info->data_alloc_cluster;
4913         }
4914
4915         if (last_ptr) {
4916                 spin_lock(&last_ptr->lock);
4917                 if (last_ptr->block_group)
4918                         hint_byte = last_ptr->window_start;
4919                 spin_unlock(&last_ptr->lock);
4920         }
4921
4922         search_start = max(search_start, first_logical_byte(root, 0));
4923         search_start = max(search_start, hint_byte);
4924
4925         if (!last_ptr)
4926                 empty_cluster = 0;
4927
4928         if (search_start == hint_byte) {
4929 ideal_cache:
4930                 block_group = btrfs_lookup_block_group(root->fs_info,
4931                                                        search_start);
4932                 /*
4933                  * we don't want to use the block group if it doesn't match our
4934                  * allocation bits, or if its not cached.
4935                  *
4936                  * However if we are re-searching with an ideal block group
4937                  * picked out then we don't care that the block group is cached.
4938                  */
4939                 if (block_group && block_group_bits(block_group, data) &&
4940                     (block_group->cached != BTRFS_CACHE_NO ||
4941                      search_start == ideal_cache_offset)) {
4942                         down_read(&space_info->groups_sem);
4943                         if (list_empty(&block_group->list) ||
4944                             block_group->ro) {
4945                                 /*
4946                                  * someone is removing this block group,
4947                                  * we can't jump into the have_block_group
4948                                  * target because our list pointers are not
4949                                  * valid
4950                                  */
4951                                 btrfs_put_block_group(block_group);
4952                                 up_read(&space_info->groups_sem);
4953                         } else {
4954                                 index = get_block_group_index(block_group);
4955                                 goto have_block_group;
4956                         }
4957                 } else if (block_group) {
4958                         btrfs_put_block_group(block_group);
4959                 }
4960         }
4961 search:
4962         down_read(&space_info->groups_sem);
4963         list_for_each_entry(block_group, &space_info->block_groups[index],
4964                             list) {
4965                 u64 offset;
4966                 int cached;
4967
4968                 btrfs_get_block_group(block_group);
4969                 search_start = block_group->key.objectid;
4970
4971                 /*
4972                  * this can happen if we end up cycling through all the
4973                  * raid types, but we want to make sure we only allocate
4974                  * for the proper type.
4975                  */
4976                 if (!block_group_bits(block_group, data)) {
4977                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
4978                                 BTRFS_BLOCK_GROUP_RAID1 |
4979                                 BTRFS_BLOCK_GROUP_RAID10;
4980
4981                         /*
4982                          * if they asked for extra copies and this block group
4983                          * doesn't provide them, bail.  This does allow us to
4984                          * fill raid0 from raid1.
4985                          */
4986                         if ((data & extra) && !(block_group->flags & extra))
4987                                 goto loop;
4988                 }
4989
4990 have_block_group:
4991                 if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
4992                         u64 free_percent;
4993
4994                         ret = cache_block_group(block_group, trans,
4995                                                 orig_root, 1);
4996                         if (block_group->cached == BTRFS_CACHE_FINISHED)
4997                                 goto have_block_group;
4998
4999                         free_percent = btrfs_block_group_used(&block_group->item);
5000                         free_percent *= 100;
5001                         free_percent = div64_u64(free_percent,
5002                                                  block_group->key.offset);
5003                         free_percent = 100 - free_percent;
5004                         if (free_percent > ideal_cache_percent &&
5005                             likely(!block_group->ro)) {
5006                                 ideal_cache_offset = block_group->key.objectid;
5007                                 ideal_cache_percent = free_percent;
5008                         }
5009
5010                         /*
5011                          * The caching workers are limited to 2 threads, so we
5012                          * can queue as much work as we care to.
5013                          */
5014                         if (loop > LOOP_FIND_IDEAL) {
5015                                 ret = cache_block_group(block_group, trans,
5016                                                         orig_root, 0);
5017                                 BUG_ON(ret);
5018                         }
5019                         found_uncached_bg = true;
5020
5021                         /*
5022                          * If loop is set for cached only, try the next block
5023                          * group.
5024                          */
5025                         if (loop == LOOP_FIND_IDEAL)
5026                                 goto loop;
5027                 }
5028
5029                 cached = block_group_cache_done(block_group);
5030                 if (unlikely(!cached))
5031                         found_uncached_bg = true;
5032
5033                 if (unlikely(block_group->ro))
5034                         goto loop;
5035
5036                 spin_lock(&block_group->free_space_ctl->tree_lock);
5037                 if (cached &&
5038                     block_group->free_space_ctl->free_space <
5039                     num_bytes + empty_size) {
5040                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5041                         goto loop;
5042                 }
5043                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5044
5045                 /*
5046                  * Ok we want to try and use the cluster allocator, so lets look
5047                  * there, unless we are on LOOP_NO_EMPTY_SIZE, since we will
5048                  * have tried the cluster allocator plenty of times at this
5049                  * point and not have found anything, so we are likely way too
5050                  * fragmented for the clustering stuff to find anything, so lets
5051                  * just skip it and let the allocator find whatever block it can
5052                  * find
5053                  */
5054                 if (last_ptr && loop < LOOP_NO_EMPTY_SIZE) {
5055                         /*
5056                          * the refill lock keeps out other
5057                          * people trying to start a new cluster
5058                          */
5059                         spin_lock(&last_ptr->refill_lock);
5060                         if (last_ptr->block_group &&
5061                             (last_ptr->block_group->ro ||
5062                             !block_group_bits(last_ptr->block_group, data))) {
5063                                 offset = 0;
5064                                 goto refill_cluster;
5065                         }
5066
5067                         offset = btrfs_alloc_from_cluster(block_group, last_ptr,
5068                                                  num_bytes, search_start);
5069                         if (offset) {
5070                                 /* we have a block, we're done */
5071                                 spin_unlock(&last_ptr->refill_lock);
5072                                 goto checks;
5073                         }
5074
5075                         spin_lock(&last_ptr->lock);
5076                         /*
5077                          * whoops, this cluster doesn't actually point to
5078                          * this block group.  Get a ref on the block
5079                          * group is does point to and try again
5080                          */
5081                         if (!last_ptr_loop && last_ptr->block_group &&
5082                             last_ptr->block_group != block_group &&
5083                             index <=
5084                                  get_block_group_index(last_ptr->block_group)) {
5085
5086                                 btrfs_put_block_group(block_group);
5087                                 block_group = last_ptr->block_group;
5088                                 btrfs_get_block_group(block_group);
5089                                 spin_unlock(&last_ptr->lock);
5090                                 spin_unlock(&last_ptr->refill_lock);
5091
5092                                 last_ptr_loop = 1;
5093                                 search_start = block_group->key.objectid;
5094                                 /*
5095                                  * we know this block group is properly
5096                                  * in the list because
5097                                  * btrfs_remove_block_group, drops the
5098                                  * cluster before it removes the block
5099                                  * group from the list
5100                                  */
5101                                 goto have_block_group;
5102                         }
5103                         spin_unlock(&last_ptr->lock);
5104 refill_cluster:
5105                         /*
5106                          * this cluster didn't work out, free it and
5107                          * start over
5108                          */
5109                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5110
5111                         last_ptr_loop = 0;
5112
5113                         /* allocate a cluster in this block group */
5114                         ret = btrfs_find_space_cluster(trans, root,
5115                                                block_group, last_ptr,
5116                                                offset, num_bytes,
5117                                                empty_cluster + empty_size);
5118                         if (ret == 0) {
5119                                 /*
5120                                  * now pull our allocation out of this
5121                                  * cluster
5122                                  */
5123                                 offset = btrfs_alloc_from_cluster(block_group,
5124                                                   last_ptr, num_bytes,
5125                                                   search_start);
5126                                 if (offset) {
5127                                         /* we found one, proceed */
5128                                         spin_unlock(&last_ptr->refill_lock);
5129                                         goto checks;
5130                                 }
5131                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5132                                    && !failed_cluster_refill) {
5133                                 spin_unlock(&last_ptr->refill_lock);
5134
5135                                 failed_cluster_refill = true;
5136                                 wait_block_group_cache_progress(block_group,
5137                                        num_bytes + empty_cluster + empty_size);
5138                                 goto have_block_group;
5139                         }
5140
5141                         /*
5142                          * at this point we either didn't find a cluster
5143                          * or we weren't able to allocate a block from our
5144                          * cluster.  Free the cluster we've been trying
5145                          * to use, and go to the next block group
5146                          */
5147                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5148                         spin_unlock(&last_ptr->refill_lock);
5149                         goto loop;
5150                 }
5151
5152                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5153                                                     num_bytes, empty_size);
5154                 /*
5155                  * If we didn't find a chunk, and we haven't failed on this
5156                  * block group before, and this block group is in the middle of
5157                  * caching and we are ok with waiting, then go ahead and wait
5158                  * for progress to be made, and set failed_alloc to true.
5159                  *
5160                  * If failed_alloc is true then we've already waited on this
5161                  * block group once and should move on to the next block group.
5162                  */
5163                 if (!offset && !failed_alloc && !cached &&
5164                     loop > LOOP_CACHING_NOWAIT) {
5165                         wait_block_group_cache_progress(block_group,
5166                                                 num_bytes + empty_size);
5167                         failed_alloc = true;
5168                         goto have_block_group;
5169                 } else if (!offset) {
5170                         goto loop;
5171                 }
5172 checks:
5173                 search_start = stripe_align(root, offset);
5174                 /* move on to the next group */
5175                 if (search_start + num_bytes >= search_end) {
5176                         btrfs_add_free_space(block_group, offset, num_bytes);
5177                         goto loop;
5178                 }
5179
5180                 /* move on to the next group */
5181                 if (search_start + num_bytes >
5182                     block_group->key.objectid + block_group->key.offset) {
5183                         btrfs_add_free_space(block_group, offset, num_bytes);
5184                         goto loop;
5185                 }
5186
5187                 ins->objectid = search_start;
5188                 ins->offset = num_bytes;
5189
5190                 if (offset < search_start)
5191                         btrfs_add_free_space(block_group, offset,
5192                                              search_start - offset);
5193                 BUG_ON(offset > search_start);
5194
5195                 ret = btrfs_update_reserved_bytes(block_group, num_bytes, 1,
5196                                             (data & BTRFS_BLOCK_GROUP_DATA));
5197                 if (ret == -EAGAIN) {
5198                         btrfs_add_free_space(block_group, offset, num_bytes);
5199                         goto loop;
5200                 }
5201
5202                 /* we are all good, lets return */
5203                 ins->objectid = search_start;
5204                 ins->offset = num_bytes;
5205
5206                 if (offset < search_start)
5207                         btrfs_add_free_space(block_group, offset,
5208                                              search_start - offset);
5209                 BUG_ON(offset > search_start);
5210                 btrfs_put_block_group(block_group);
5211                 break;
5212 loop:
5213                 failed_cluster_refill = false;
5214                 failed_alloc = false;
5215                 BUG_ON(index != get_block_group_index(block_group));
5216                 btrfs_put_block_group(block_group);
5217         }
5218         up_read(&space_info->groups_sem);
5219
5220         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5221                 goto search;
5222
5223         /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
5224          *                      for them to make caching progress.  Also
5225          *                      determine the best possible bg to cache
5226          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5227          *                      caching kthreads as we move along
5228          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5229          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5230          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5231          *                      again
5232          */
5233         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5234                 index = 0;
5235                 if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
5236                         found_uncached_bg = false;
5237                         loop++;
5238                         if (!ideal_cache_percent)
5239                                 goto search;
5240
5241                         /*
5242                          * 1 of the following 2 things have happened so far
5243                          *
5244                          * 1) We found an ideal block group for caching that
5245                          * is mostly full and will cache quickly, so we might
5246                          * as well wait for it.
5247                          *
5248                          * 2) We searched for cached only and we didn't find
5249                          * anything, and we didn't start any caching kthreads
5250                          * either, so chances are we will loop through and
5251                          * start a couple caching kthreads, and then come back
5252                          * around and just wait for them.  This will be slower
5253                          * because we will have 2 caching kthreads reading at
5254                          * the same time when we could have just started one
5255                          * and waited for it to get far enough to give us an
5256                          * allocation, so go ahead and go to the wait caching
5257                          * loop.
5258                          */
5259                         loop = LOOP_CACHING_WAIT;
5260                         search_start = ideal_cache_offset;
5261                         ideal_cache_percent = 0;
5262                         goto ideal_cache;
5263                 } else if (loop == LOOP_FIND_IDEAL) {
5264                         /*
5265                          * Didn't find a uncached bg, wait on anything we find
5266                          * next.
5267                          */
5268                         loop = LOOP_CACHING_WAIT;
5269                         goto search;
5270                 }
5271
5272                 loop++;
5273
5274                 if (loop == LOOP_ALLOC_CHUNK) {
5275                        if (allowed_chunk_alloc) {
5276                                 ret = do_chunk_alloc(trans, root, num_bytes +
5277                                                      2 * 1024 * 1024, data,
5278                                                      CHUNK_ALLOC_LIMITED);
5279                                 allowed_chunk_alloc = 0;
5280                                 if (ret == 1)
5281                                         done_chunk_alloc = 1;
5282                         } else if (!done_chunk_alloc &&
5283                                    space_info->force_alloc ==
5284                                    CHUNK_ALLOC_NO_FORCE) {
5285                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5286                         }
5287
5288                        /*
5289                         * We didn't allocate a chunk, go ahead and drop the
5290                         * empty size and loop again.
5291                         */
5292                        if (!done_chunk_alloc)
5293                                loop = LOOP_NO_EMPTY_SIZE;
5294                 }
5295
5296                 if (loop == LOOP_NO_EMPTY_SIZE) {
5297                         empty_size = 0;
5298                         empty_cluster = 0;
5299                 }
5300
5301                 goto search;
5302         } else if (!ins->objectid) {
5303                 ret = -ENOSPC;
5304         } else if (ins->objectid) {
5305                 ret = 0;
5306         }
5307
5308         return ret;
5309 }
5310
5311 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5312                             int dump_block_groups)
5313 {
5314         struct btrfs_block_group_cache *cache;
5315         int index = 0;
5316
5317         spin_lock(&info->lock);
5318         printk(KERN_INFO "space_info has %llu free, is %sfull\n",
5319                (unsigned long long)(info->total_bytes - info->bytes_used -
5320                                     info->bytes_pinned - info->bytes_reserved -
5321                                     info->bytes_readonly),
5322                (info->full) ? "" : "not ");
5323         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5324                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5325                (unsigned long long)info->total_bytes,
5326                (unsigned long long)info->bytes_used,
5327                (unsigned long long)info->bytes_pinned,
5328                (unsigned long long)info->bytes_reserved,
5329                (unsigned long long)info->bytes_may_use,
5330                (unsigned long long)info->bytes_readonly);
5331         spin_unlock(&info->lock);
5332
5333         if (!dump_block_groups)
5334                 return;
5335
5336         down_read(&info->groups_sem);
5337 again:
5338         list_for_each_entry(cache, &info->block_groups[index], list) {
5339                 spin_lock(&cache->lock);
5340                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5341                        "%llu pinned %llu reserved\n",
5342                        (unsigned long long)cache->key.objectid,
5343                        (unsigned long long)cache->key.offset,
5344                        (unsigned long long)btrfs_block_group_used(&cache->item),
5345                        (unsigned long long)cache->pinned,
5346                        (unsigned long long)cache->reserved);
5347                 btrfs_dump_free_space(cache, bytes);
5348                 spin_unlock(&cache->lock);
5349         }
5350         if (++index < BTRFS_NR_RAID_TYPES)
5351                 goto again;
5352         up_read(&info->groups_sem);
5353 }
5354
5355 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5356                          struct btrfs_root *root,
5357                          u64 num_bytes, u64 min_alloc_size,
5358                          u64 empty_size, u64 hint_byte,
5359                          u64 search_end, struct btrfs_key *ins,
5360                          u64 data)
5361 {
5362         int ret;
5363         u64 search_start = 0;
5364
5365         data = btrfs_get_alloc_profile(root, data);
5366 again:
5367         /*
5368          * the only place that sets empty_size is btrfs_realloc_node, which
5369          * is not called recursively on allocations
5370          */
5371         if (empty_size || root->ref_cows)
5372                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5373                                      num_bytes + 2 * 1024 * 1024, data,
5374                                      CHUNK_ALLOC_NO_FORCE);
5375
5376         WARN_ON(num_bytes < root->sectorsize);
5377         ret = find_free_extent(trans, root, num_bytes, empty_size,
5378                                search_start, search_end, hint_byte,
5379                                ins, data);
5380
5381         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
5382                 num_bytes = num_bytes >> 1;
5383                 num_bytes = num_bytes & ~(root->sectorsize - 1);
5384                 num_bytes = max(num_bytes, min_alloc_size);
5385                 do_chunk_alloc(trans, root->fs_info->extent_root,
5386                                num_bytes, data, CHUNK_ALLOC_FORCE);
5387                 goto again;
5388         }
5389         if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) {
5390                 struct btrfs_space_info *sinfo;
5391
5392                 sinfo = __find_space_info(root->fs_info, data);
5393                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
5394                        "wanted %llu\n", (unsigned long long)data,
5395                        (unsigned long long)num_bytes);
5396                 dump_space_info(sinfo, num_bytes, 1);
5397         }
5398
5399         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5400
5401         return ret;
5402 }
5403
5404 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
5405 {
5406         struct btrfs_block_group_cache *cache;
5407         int ret = 0;
5408
5409         cache = btrfs_lookup_block_group(root->fs_info, start);
5410         if (!cache) {
5411                 printk(KERN_ERR "Unable to find block group for %llu\n",
5412                        (unsigned long long)start);
5413                 return -ENOSPC;
5414         }
5415
5416         if (btrfs_test_opt(root, DISCARD))
5417                 ret = btrfs_discard_extent(root, start, len, NULL);
5418
5419         btrfs_add_free_space(cache, start, len);
5420         btrfs_update_reserved_bytes(cache, len, 0, 1);
5421         btrfs_put_block_group(cache);
5422
5423         trace_btrfs_reserved_extent_free(root, start, len);
5424
5425         return ret;
5426 }
5427
5428 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5429                                       struct btrfs_root *root,
5430                                       u64 parent, u64 root_objectid,
5431                                       u64 flags, u64 owner, u64 offset,
5432                                       struct btrfs_key *ins, int ref_mod)
5433 {
5434         int ret;
5435         struct btrfs_fs_info *fs_info = root->fs_info;
5436         struct btrfs_extent_item *extent_item;
5437         struct btrfs_extent_inline_ref *iref;
5438         struct btrfs_path *path;
5439         struct extent_buffer *leaf;
5440         int type;
5441         u32 size;
5442
5443         if (parent > 0)
5444                 type = BTRFS_SHARED_DATA_REF_KEY;
5445         else
5446                 type = BTRFS_EXTENT_DATA_REF_KEY;
5447
5448         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5449
5450         path = btrfs_alloc_path();
5451         if (!path)
5452                 return -ENOMEM;
5453
5454         path->leave_spinning = 1;
5455         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5456                                       ins, size);
5457         BUG_ON(ret);
5458
5459         leaf = path->nodes[0];
5460         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5461                                      struct btrfs_extent_item);
5462         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5463         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5464         btrfs_set_extent_flags(leaf, extent_item,
5465                                flags | BTRFS_EXTENT_FLAG_DATA);
5466
5467         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5468         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5469         if (parent > 0) {
5470                 struct btrfs_shared_data_ref *ref;
5471                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5472                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5473                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5474         } else {
5475                 struct btrfs_extent_data_ref *ref;
5476                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5477                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5478                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5479                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5480                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5481         }
5482
5483         btrfs_mark_buffer_dirty(path->nodes[0]);
5484         btrfs_free_path(path);
5485
5486         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5487         if (ret) {
5488                 printk(KERN_ERR "btrfs update block group failed for %llu "
5489                        "%llu\n", (unsigned long long)ins->objectid,
5490                        (unsigned long long)ins->offset);
5491                 BUG();
5492         }
5493         return ret;
5494 }
5495
5496 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5497                                      struct btrfs_root *root,
5498                                      u64 parent, u64 root_objectid,
5499                                      u64 flags, struct btrfs_disk_key *key,
5500                                      int level, struct btrfs_key *ins)
5501 {
5502         int ret;
5503         struct btrfs_fs_info *fs_info = root->fs_info;
5504         struct btrfs_extent_item *extent_item;
5505         struct btrfs_tree_block_info *block_info;
5506         struct btrfs_extent_inline_ref *iref;
5507         struct btrfs_path *path;
5508         struct extent_buffer *leaf;
5509         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5510
5511         path = btrfs_alloc_path();
5512         if (!path)
5513                 return -ENOMEM;
5514
5515         path->leave_spinning = 1;
5516         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5517                                       ins, size);
5518         BUG_ON(ret);
5519
5520         leaf = path->nodes[0];
5521         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5522                                      struct btrfs_extent_item);
5523         btrfs_set_extent_refs(leaf, extent_item, 1);
5524         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5525         btrfs_set_extent_flags(leaf, extent_item,
5526                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
5527         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
5528
5529         btrfs_set_tree_block_key(leaf, block_info, key);
5530         btrfs_set_tree_block_level(leaf, block_info, level);
5531
5532         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
5533         if (parent > 0) {
5534                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
5535                 btrfs_set_extent_inline_ref_type(leaf, iref,
5536                                                  BTRFS_SHARED_BLOCK_REF_KEY);
5537                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5538         } else {
5539                 btrfs_set_extent_inline_ref_type(leaf, iref,
5540                                                  BTRFS_TREE_BLOCK_REF_KEY);
5541                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
5542         }
5543
5544         btrfs_mark_buffer_dirty(leaf);
5545         btrfs_free_path(path);
5546
5547         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5548         if (ret) {
5549                 printk(KERN_ERR "btrfs update block group failed for %llu "
5550                        "%llu\n", (unsigned long long)ins->objectid,
5551                        (unsigned long long)ins->offset);
5552                 BUG();
5553         }
5554         return ret;
5555 }
5556
5557 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5558                                      struct btrfs_root *root,
5559                                      u64 root_objectid, u64 owner,
5560                                      u64 offset, struct btrfs_key *ins)
5561 {
5562         int ret;
5563
5564         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
5565
5566         ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
5567                                          0, root_objectid, owner, offset,
5568                                          BTRFS_ADD_DELAYED_EXTENT, NULL);
5569         return ret;
5570 }
5571
5572 /*
5573  * this is used by the tree logging recovery code.  It records that
5574  * an extent has been allocated and makes sure to clear the free
5575  * space cache bits as well
5576  */
5577 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
5578                                    struct btrfs_root *root,
5579                                    u64 root_objectid, u64 owner, u64 offset,
5580                                    struct btrfs_key *ins)
5581 {
5582         int ret;
5583         struct btrfs_block_group_cache *block_group;
5584         struct btrfs_caching_control *caching_ctl;
5585         u64 start = ins->objectid;
5586         u64 num_bytes = ins->offset;
5587
5588         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
5589         cache_block_group(block_group, trans, NULL, 0);
5590         caching_ctl = get_caching_control(block_group);
5591
5592         if (!caching_ctl) {
5593                 BUG_ON(!block_group_cache_done(block_group));
5594                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5595                 BUG_ON(ret);
5596         } else {
5597                 mutex_lock(&caching_ctl->mutex);
5598
5599                 if (start >= caching_ctl->progress) {
5600                         ret = add_excluded_extent(root, start, num_bytes);
5601                         BUG_ON(ret);
5602                 } else if (start + num_bytes <= caching_ctl->progress) {
5603                         ret = btrfs_remove_free_space(block_group,
5604                                                       start, num_bytes);
5605                         BUG_ON(ret);
5606                 } else {
5607                         num_bytes = caching_ctl->progress - start;
5608                         ret = btrfs_remove_free_space(block_group,
5609                                                       start, num_bytes);
5610                         BUG_ON(ret);
5611
5612                         start = caching_ctl->progress;
5613                         num_bytes = ins->objectid + ins->offset -
5614                                     caching_ctl->progress;
5615                         ret = add_excluded_extent(root, start, num_bytes);
5616                         BUG_ON(ret);
5617                 }
5618
5619                 mutex_unlock(&caching_ctl->mutex);
5620                 put_caching_control(caching_ctl);
5621         }
5622
5623         ret = btrfs_update_reserved_bytes(block_group, ins->offset, 1, 1);
5624         BUG_ON(ret);
5625         btrfs_put_block_group(block_group);
5626         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
5627                                          0, owner, offset, ins, 1);
5628         return ret;
5629 }
5630
5631 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
5632                                             struct btrfs_root *root,
5633                                             u64 bytenr, u32 blocksize,
5634                                             int level)
5635 {
5636         struct extent_buffer *buf;
5637
5638         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
5639         if (!buf)
5640                 return ERR_PTR(-ENOMEM);
5641         btrfs_set_header_generation(buf, trans->transid);
5642         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
5643         btrfs_tree_lock(buf);
5644         clean_tree_block(trans, root, buf);
5645
5646         btrfs_set_lock_blocking(buf);
5647         btrfs_set_buffer_uptodate(buf);
5648
5649         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
5650                 /*
5651                  * we allow two log transactions at a time, use different
5652                  * EXENT bit to differentiate dirty pages.
5653                  */
5654                 if (root->log_transid % 2 == 0)
5655                         set_extent_dirty(&root->dirty_log_pages, buf->start,
5656                                         buf->start + buf->len - 1, GFP_NOFS);
5657                 else
5658                         set_extent_new(&root->dirty_log_pages, buf->start,
5659                                         buf->start + buf->len - 1, GFP_NOFS);
5660         } else {
5661                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
5662                          buf->start + buf->len - 1, GFP_NOFS);
5663         }
5664         trans->blocks_used++;
5665         /* this returns a buffer locked for blocking */
5666         return buf;
5667 }
5668
5669 static struct btrfs_block_rsv *
5670 use_block_rsv(struct btrfs_trans_handle *trans,
5671               struct btrfs_root *root, u32 blocksize)
5672 {
5673         struct btrfs_block_rsv *block_rsv;
5674         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5675         int ret;
5676
5677         block_rsv = get_block_rsv(trans, root);
5678
5679         if (block_rsv->size == 0) {
5680                 ret = reserve_metadata_bytes(trans, root, block_rsv,
5681                                              blocksize, 0);
5682                 /*
5683                  * If we couldn't reserve metadata bytes try and use some from
5684                  * the global reserve.
5685                  */
5686                 if (ret && block_rsv != global_rsv) {
5687                         ret = block_rsv_use_bytes(global_rsv, blocksize);
5688                         if (!ret)
5689                                 return global_rsv;
5690                         return ERR_PTR(ret);
5691                 } else if (ret) {
5692                         return ERR_PTR(ret);
5693                 }
5694                 return block_rsv;
5695         }
5696
5697         ret = block_rsv_use_bytes(block_rsv, blocksize);
5698         if (!ret)
5699                 return block_rsv;
5700         if (ret) {
5701                 WARN_ON(1);
5702                 ret = reserve_metadata_bytes(trans, root, block_rsv, blocksize,
5703                                              0);
5704                 if (!ret) {
5705                         spin_lock(&block_rsv->lock);
5706                         block_rsv->size += blocksize;
5707                         spin_unlock(&block_rsv->lock);
5708                         return block_rsv;
5709                 } else if (ret && block_rsv != global_rsv) {
5710                         ret = block_rsv_use_bytes(global_rsv, blocksize);
5711                         if (!ret)
5712                                 return global_rsv;
5713                 }
5714         }
5715
5716         return ERR_PTR(-ENOSPC);
5717 }
5718
5719 static void unuse_block_rsv(struct btrfs_block_rsv *block_rsv, u32 blocksize)
5720 {
5721         block_rsv_add_bytes(block_rsv, blocksize, 0);
5722         block_rsv_release_bytes(block_rsv, NULL, 0);
5723 }
5724
5725 /*
5726  * finds a free extent and does all the dirty work required for allocation
5727  * returns the key for the extent through ins, and a tree buffer for
5728  * the first block of the extent through buf.
5729  *
5730  * returns the tree buffer or NULL.
5731  */
5732 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
5733                                         struct btrfs_root *root, u32 blocksize,
5734                                         u64 parent, u64 root_objectid,
5735                                         struct btrfs_disk_key *key, int level,
5736                                         u64 hint, u64 empty_size)
5737 {
5738         struct btrfs_key ins;
5739         struct btrfs_block_rsv *block_rsv;
5740         struct extent_buffer *buf;
5741         u64 flags = 0;
5742         int ret;
5743
5744
5745         block_rsv = use_block_rsv(trans, root, blocksize);
5746         if (IS_ERR(block_rsv))
5747                 return ERR_CAST(block_rsv);
5748
5749         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
5750                                    empty_size, hint, (u64)-1, &ins, 0);
5751         if (ret) {
5752                 unuse_block_rsv(block_rsv, blocksize);
5753                 return ERR_PTR(ret);
5754         }
5755
5756         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
5757                                     blocksize, level);
5758         BUG_ON(IS_ERR(buf));
5759
5760         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
5761                 if (parent == 0)
5762                         parent = ins.objectid;
5763                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
5764         } else
5765                 BUG_ON(parent > 0);
5766
5767         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
5768                 struct btrfs_delayed_extent_op *extent_op;
5769                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
5770                 BUG_ON(!extent_op);
5771                 if (key)
5772                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
5773                 else
5774                         memset(&extent_op->key, 0, sizeof(extent_op->key));
5775                 extent_op->flags_to_set = flags;
5776                 extent_op->update_key = 1;
5777                 extent_op->update_flags = 1;
5778                 extent_op->is_data = 0;
5779
5780                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
5781                                         ins.offset, parent, root_objectid,
5782                                         level, BTRFS_ADD_DELAYED_EXTENT,
5783                                         extent_op);
5784                 BUG_ON(ret);
5785         }
5786         return buf;
5787 }
5788
5789 struct walk_control {
5790         u64 refs[BTRFS_MAX_LEVEL];
5791         u64 flags[BTRFS_MAX_LEVEL];
5792         struct btrfs_key update_progress;
5793         int stage;
5794         int level;
5795         int shared_level;
5796         int update_ref;
5797         int keep_locks;
5798         int reada_slot;
5799         int reada_count;
5800 };
5801
5802 #define DROP_REFERENCE  1
5803 #define UPDATE_BACKREF  2
5804
5805 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
5806                                      struct btrfs_root *root,
5807                                      struct walk_control *wc,
5808                                      struct btrfs_path *path)
5809 {
5810         u64 bytenr;
5811         u64 generation;
5812         u64 refs;
5813         u64 flags;
5814         u32 nritems;
5815         u32 blocksize;
5816         struct btrfs_key key;
5817         struct extent_buffer *eb;
5818         int ret;
5819         int slot;
5820         int nread = 0;
5821
5822         if (path->slots[wc->level] < wc->reada_slot) {
5823                 wc->reada_count = wc->reada_count * 2 / 3;
5824                 wc->reada_count = max(wc->reada_count, 2);
5825         } else {
5826                 wc->reada_count = wc->reada_count * 3 / 2;
5827                 wc->reada_count = min_t(int, wc->reada_count,
5828                                         BTRFS_NODEPTRS_PER_BLOCK(root));
5829         }
5830
5831         eb = path->nodes[wc->level];
5832         nritems = btrfs_header_nritems(eb);
5833         blocksize = btrfs_level_size(root, wc->level - 1);
5834
5835         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
5836                 if (nread >= wc->reada_count)
5837                         break;
5838
5839                 cond_resched();
5840                 bytenr = btrfs_node_blockptr(eb, slot);
5841                 generation = btrfs_node_ptr_generation(eb, slot);
5842
5843                 if (slot == path->slots[wc->level])
5844                         goto reada;
5845
5846                 if (wc->stage == UPDATE_BACKREF &&
5847                     generation <= root->root_key.offset)
5848                         continue;
5849
5850                 /* We don't lock the tree block, it's OK to be racy here */
5851                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
5852                                                &refs, &flags);
5853                 BUG_ON(ret);
5854                 BUG_ON(refs == 0);
5855
5856                 if (wc->stage == DROP_REFERENCE) {
5857                         if (refs == 1)
5858                                 goto reada;
5859
5860                         if (wc->level == 1 &&
5861                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5862                                 continue;
5863                         if (!wc->update_ref ||
5864                             generation <= root->root_key.offset)
5865                                 continue;
5866                         btrfs_node_key_to_cpu(eb, &key, slot);
5867                         ret = btrfs_comp_cpu_keys(&key,
5868                                                   &wc->update_progress);
5869                         if (ret < 0)
5870                                 continue;
5871                 } else {
5872                         if (wc->level == 1 &&
5873                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5874                                 continue;
5875                 }
5876 reada:
5877                 ret = readahead_tree_block(root, bytenr, blocksize,
5878                                            generation);
5879                 if (ret)
5880                         break;
5881                 nread++;
5882         }
5883         wc->reada_slot = slot;
5884 }
5885
5886 /*
5887  * hepler to process tree block while walking down the tree.
5888  *
5889  * when wc->stage == UPDATE_BACKREF, this function updates
5890  * back refs for pointers in the block.
5891  *
5892  * NOTE: return value 1 means we should stop walking down.
5893  */
5894 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
5895                                    struct btrfs_root *root,
5896                                    struct btrfs_path *path,
5897                                    struct walk_control *wc, int lookup_info)
5898 {
5899         int level = wc->level;
5900         struct extent_buffer *eb = path->nodes[level];
5901         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5902         int ret;
5903
5904         if (wc->stage == UPDATE_BACKREF &&
5905             btrfs_header_owner(eb) != root->root_key.objectid)
5906                 return 1;
5907
5908         /*
5909          * when reference count of tree block is 1, it won't increase
5910          * again. once full backref flag is set, we never clear it.
5911          */
5912         if (lookup_info &&
5913             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
5914              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
5915                 BUG_ON(!path->locks[level]);
5916                 ret = btrfs_lookup_extent_info(trans, root,
5917                                                eb->start, eb->len,
5918                                                &wc->refs[level],
5919                                                &wc->flags[level]);
5920                 BUG_ON(ret);
5921                 BUG_ON(wc->refs[level] == 0);
5922         }
5923
5924         if (wc->stage == DROP_REFERENCE) {
5925                 if (wc->refs[level] > 1)
5926                         return 1;
5927
5928                 if (path->locks[level] && !wc->keep_locks) {
5929                         btrfs_tree_unlock_rw(eb, path->locks[level]);
5930                         path->locks[level] = 0;
5931                 }
5932                 return 0;
5933         }
5934
5935         /* wc->stage == UPDATE_BACKREF */
5936         if (!(wc->flags[level] & flag)) {
5937                 BUG_ON(!path->locks[level]);
5938                 ret = btrfs_inc_ref(trans, root, eb, 1);
5939                 BUG_ON(ret);
5940                 ret = btrfs_dec_ref(trans, root, eb, 0);
5941                 BUG_ON(ret);
5942                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
5943                                                   eb->len, flag, 0);
5944                 BUG_ON(ret);
5945                 wc->flags[level] |= flag;
5946         }
5947
5948         /*
5949          * the block is shared by multiple trees, so it's not good to
5950          * keep the tree lock
5951          */
5952         if (path->locks[level] && level > 0) {
5953                 btrfs_tree_unlock_rw(eb, path->locks[level]);
5954                 path->locks[level] = 0;
5955         }
5956         return 0;
5957 }
5958
5959 /*
5960  * hepler to process tree block pointer.
5961  *
5962  * when wc->stage == DROP_REFERENCE, this function checks
5963  * reference count of the block pointed to. if the block
5964  * is shared and we need update back refs for the subtree
5965  * rooted at the block, this function changes wc->stage to
5966  * UPDATE_BACKREF. if the block is shared and there is no
5967  * need to update back, this function drops the reference
5968  * to the block.
5969  *
5970  * NOTE: return value 1 means we should stop walking down.
5971  */
5972 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
5973                                  struct btrfs_root *root,
5974                                  struct btrfs_path *path,
5975                                  struct walk_control *wc, int *lookup_info)
5976 {
5977         u64 bytenr;
5978         u64 generation;
5979         u64 parent;
5980         u32 blocksize;
5981         struct btrfs_key key;
5982         struct extent_buffer *next;
5983         int level = wc->level;
5984         int reada = 0;
5985         int ret = 0;
5986
5987         generation = btrfs_node_ptr_generation(path->nodes[level],
5988                                                path->slots[level]);
5989         /*
5990          * if the lower level block was created before the snapshot
5991          * was created, we know there is no need to update back refs
5992          * for the subtree
5993          */
5994         if (wc->stage == UPDATE_BACKREF &&
5995             generation <= root->root_key.offset) {
5996                 *lookup_info = 1;
5997                 return 1;
5998         }
5999
6000         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6001         blocksize = btrfs_level_size(root, level - 1);
6002
6003         next = btrfs_find_tree_block(root, bytenr, blocksize);
6004         if (!next) {
6005                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6006                 if (!next)
6007                         return -ENOMEM;
6008                 reada = 1;
6009         }
6010         btrfs_tree_lock(next);
6011         btrfs_set_lock_blocking(next);
6012
6013         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6014                                        &wc->refs[level - 1],
6015                                        &wc->flags[level - 1]);
6016         BUG_ON(ret);
6017         BUG_ON(wc->refs[level - 1] == 0);
6018         *lookup_info = 0;
6019
6020         if (wc->stage == DROP_REFERENCE) {
6021                 if (wc->refs[level - 1] > 1) {
6022                         if (level == 1 &&
6023                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6024                                 goto skip;
6025
6026                         if (!wc->update_ref ||
6027                             generation <= root->root_key.offset)
6028                                 goto skip;
6029
6030                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6031                                               path->slots[level]);
6032                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6033                         if (ret < 0)
6034                                 goto skip;
6035
6036                         wc->stage = UPDATE_BACKREF;
6037                         wc->shared_level = level - 1;
6038                 }
6039         } else {
6040                 if (level == 1 &&
6041                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6042                         goto skip;
6043         }
6044
6045         if (!btrfs_buffer_uptodate(next, generation)) {
6046                 btrfs_tree_unlock(next);
6047                 free_extent_buffer(next);
6048                 next = NULL;
6049                 *lookup_info = 1;
6050         }
6051
6052         if (!next) {
6053                 if (reada && level == 1)
6054                         reada_walk_down(trans, root, wc, path);
6055                 next = read_tree_block(root, bytenr, blocksize, generation);
6056                 if (!next)
6057                         return -EIO;
6058                 btrfs_tree_lock(next);
6059                 btrfs_set_lock_blocking(next);
6060         }
6061
6062         level--;
6063         BUG_ON(level != btrfs_header_level(next));
6064         path->nodes[level] = next;
6065         path->slots[level] = 0;
6066         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6067         wc->level = level;
6068         if (wc->level == 1)
6069                 wc->reada_slot = 0;
6070         return 0;
6071 skip:
6072         wc->refs[level - 1] = 0;
6073         wc->flags[level - 1] = 0;
6074         if (wc->stage == DROP_REFERENCE) {
6075                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6076                         parent = path->nodes[level]->start;
6077                 } else {
6078                         BUG_ON(root->root_key.objectid !=
6079                                btrfs_header_owner(path->nodes[level]));
6080                         parent = 0;
6081                 }
6082
6083                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6084                                         root->root_key.objectid, level - 1, 0);
6085                 BUG_ON(ret);
6086         }
6087         btrfs_tree_unlock(next);
6088         free_extent_buffer(next);
6089         *lookup_info = 1;
6090         return 1;
6091 }
6092
6093 /*
6094  * hepler to process tree block while walking up the tree.
6095  *
6096  * when wc->stage == DROP_REFERENCE, this function drops
6097  * reference count on the block.
6098  *
6099  * when wc->stage == UPDATE_BACKREF, this function changes
6100  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6101  * to UPDATE_BACKREF previously while processing the block.
6102  *
6103  * NOTE: return value 1 means we should stop walking up.
6104  */
6105 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6106                                  struct btrfs_root *root,
6107                                  struct btrfs_path *path,
6108                                  struct walk_control *wc)
6109 {
6110         int ret;
6111         int level = wc->level;
6112         struct extent_buffer *eb = path->nodes[level];
6113         u64 parent = 0;
6114
6115         if (wc->stage == UPDATE_BACKREF) {
6116                 BUG_ON(wc->shared_level < level);
6117                 if (level < wc->shared_level)
6118                         goto out;
6119
6120                 ret = find_next_key(path, level + 1, &wc->update_progress);
6121                 if (ret > 0)
6122                         wc->update_ref = 0;
6123
6124                 wc->stage = DROP_REFERENCE;
6125                 wc->shared_level = -1;
6126                 path->slots[level] = 0;
6127
6128                 /*
6129                  * check reference count again if the block isn't locked.
6130                  * we should start walking down the tree again if reference
6131                  * count is one.
6132                  */
6133                 if (!path->locks[level]) {
6134                         BUG_ON(level == 0);
6135                         btrfs_tree_lock(eb);
6136                         btrfs_set_lock_blocking(eb);
6137                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6138
6139                         ret = btrfs_lookup_extent_info(trans, root,
6140                                                        eb->start, eb->len,
6141                                                        &wc->refs[level],
6142                                                        &wc->flags[level]);
6143                         BUG_ON(ret);
6144                         BUG_ON(wc->refs[level] == 0);
6145                         if (wc->refs[level] == 1) {
6146                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6147                                 return 1;
6148                         }
6149                 }
6150         }
6151
6152         /* wc->stage == DROP_REFERENCE */
6153         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6154
6155         if (wc->refs[level] == 1) {
6156                 if (level == 0) {
6157                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6158                                 ret = btrfs_dec_ref(trans, root, eb, 1);
6159                         else
6160                                 ret = btrfs_dec_ref(trans, root, eb, 0);
6161                         BUG_ON(ret);
6162                 }
6163                 /* make block locked assertion in clean_tree_block happy */
6164                 if (!path->locks[level] &&
6165                     btrfs_header_generation(eb) == trans->transid) {
6166                         btrfs_tree_lock(eb);
6167                         btrfs_set_lock_blocking(eb);
6168                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6169                 }
6170                 clean_tree_block(trans, root, eb);
6171         }
6172
6173         if (eb == root->node) {
6174                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6175                         parent = eb->start;
6176                 else
6177                         BUG_ON(root->root_key.objectid !=
6178                                btrfs_header_owner(eb));
6179         } else {
6180                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6181                         parent = path->nodes[level + 1]->start;
6182                 else
6183                         BUG_ON(root->root_key.objectid !=
6184                                btrfs_header_owner(path->nodes[level + 1]));
6185         }
6186
6187         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
6188 out:
6189         wc->refs[level] = 0;
6190         wc->flags[level] = 0;
6191         return 0;
6192 }
6193
6194 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6195                                    struct btrfs_root *root,
6196                                    struct btrfs_path *path,
6197                                    struct walk_control *wc)
6198 {
6199         int level = wc->level;
6200         int lookup_info = 1;
6201         int ret;
6202
6203         while (level >= 0) {
6204                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6205                 if (ret > 0)
6206                         break;
6207
6208                 if (level == 0)
6209                         break;
6210
6211                 if (path->slots[level] >=
6212                     btrfs_header_nritems(path->nodes[level]))
6213                         break;
6214
6215                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6216                 if (ret > 0) {
6217                         path->slots[level]++;
6218                         continue;
6219                 } else if (ret < 0)
6220                         return ret;
6221                 level = wc->level;
6222         }
6223         return 0;
6224 }
6225
6226 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6227                                  struct btrfs_root *root,
6228                                  struct btrfs_path *path,
6229                                  struct walk_control *wc, int max_level)
6230 {
6231         int level = wc->level;
6232         int ret;
6233
6234         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6235         while (level < max_level && path->nodes[level]) {
6236                 wc->level = level;
6237                 if (path->slots[level] + 1 <
6238                     btrfs_header_nritems(path->nodes[level])) {
6239                         path->slots[level]++;
6240                         return 0;
6241                 } else {
6242                         ret = walk_up_proc(trans, root, path, wc);
6243                         if (ret > 0)
6244                                 return 0;
6245
6246                         if (path->locks[level]) {
6247                                 btrfs_tree_unlock_rw(path->nodes[level],
6248                                                      path->locks[level]);
6249                                 path->locks[level] = 0;
6250                         }
6251                         free_extent_buffer(path->nodes[level]);
6252                         path->nodes[level] = NULL;
6253                         level++;
6254                 }
6255         }
6256         return 1;
6257 }
6258
6259 /*
6260  * drop a subvolume tree.
6261  *
6262  * this function traverses the tree freeing any blocks that only
6263  * referenced by the tree.
6264  *
6265  * when a shared tree block is found. this function decreases its
6266  * reference count by one. if update_ref is true, this function
6267  * also make sure backrefs for the shared block and all lower level
6268  * blocks are properly updated.
6269  */
6270 int btrfs_drop_snapshot(struct btrfs_root *root,
6271                         struct btrfs_block_rsv *block_rsv, int update_ref)
6272 {
6273         struct btrfs_path *path;
6274         struct btrfs_trans_handle *trans;
6275         struct btrfs_root *tree_root = root->fs_info->tree_root;
6276         struct btrfs_root_item *root_item = &root->root_item;
6277         struct walk_control *wc;
6278         struct btrfs_key key;
6279         int err = 0;
6280         int ret;
6281         int level;
6282
6283         path = btrfs_alloc_path();
6284         if (!path)
6285                 return -ENOMEM;
6286
6287         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6288         if (!wc) {
6289                 btrfs_free_path(path);
6290                 return -ENOMEM;
6291         }
6292
6293         trans = btrfs_start_transaction(tree_root, 0);
6294         BUG_ON(IS_ERR(trans));
6295
6296         if (block_rsv)
6297                 trans->block_rsv = block_rsv;
6298
6299         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6300                 level = btrfs_header_level(root->node);
6301                 path->nodes[level] = btrfs_lock_root_node(root);
6302                 btrfs_set_lock_blocking(path->nodes[level]);
6303                 path->slots[level] = 0;
6304                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6305                 memset(&wc->update_progress, 0,
6306                        sizeof(wc->update_progress));
6307         } else {
6308                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6309                 memcpy(&wc->update_progress, &key,
6310                        sizeof(wc->update_progress));
6311
6312                 level = root_item->drop_level;
6313                 BUG_ON(level == 0);
6314                 path->lowest_level = level;
6315                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6316                 path->lowest_level = 0;
6317                 if (ret < 0) {
6318                         err = ret;
6319                         goto out;
6320                 }
6321                 WARN_ON(ret > 0);
6322
6323                 /*
6324                  * unlock our path, this is safe because only this
6325                  * function is allowed to delete this snapshot
6326                  */
6327                 btrfs_unlock_up_safe(path, 0);
6328
6329                 level = btrfs_header_level(root->node);
6330                 while (1) {
6331                         btrfs_tree_lock(path->nodes[level]);
6332                         btrfs_set_lock_blocking(path->nodes[level]);
6333
6334                         ret = btrfs_lookup_extent_info(trans, root,
6335                                                 path->nodes[level]->start,
6336                                                 path->nodes[level]->len,
6337                                                 &wc->refs[level],
6338                                                 &wc->flags[level]);
6339                         BUG_ON(ret);
6340                         BUG_ON(wc->refs[level] == 0);
6341
6342                         if (level == root_item->drop_level)
6343                                 break;
6344
6345                         btrfs_tree_unlock(path->nodes[level]);
6346                         WARN_ON(wc->refs[level] != 1);
6347                         level--;
6348                 }
6349         }
6350
6351         wc->level = level;
6352         wc->shared_level = -1;
6353         wc->stage = DROP_REFERENCE;
6354         wc->update_ref = update_ref;
6355         wc->keep_locks = 0;
6356         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6357
6358         while (1) {
6359                 ret = walk_down_tree(trans, root, path, wc);
6360                 if (ret < 0) {
6361                         err = ret;
6362                         break;
6363                 }
6364
6365                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6366                 if (ret < 0) {
6367                         err = ret;
6368                         break;
6369                 }
6370
6371                 if (ret > 0) {
6372                         BUG_ON(wc->stage != DROP_REFERENCE);
6373                         break;
6374                 }
6375
6376                 if (wc->stage == DROP_REFERENCE) {
6377                         level = wc->level;
6378                         btrfs_node_key(path->nodes[level],
6379                                        &root_item->drop_progress,
6380                                        path->slots[level]);
6381                         root_item->drop_level = level;
6382                 }
6383
6384                 BUG_ON(wc->level == 0);
6385                 if (btrfs_should_end_transaction(trans, tree_root)) {
6386                         ret = btrfs_update_root(trans, tree_root,
6387                                                 &root->root_key,
6388                                                 root_item);
6389                         BUG_ON(ret);
6390
6391                         btrfs_end_transaction_throttle(trans, tree_root);
6392                         trans = btrfs_start_transaction(tree_root, 0);
6393                         BUG_ON(IS_ERR(trans));
6394                         if (block_rsv)
6395                                 trans->block_rsv = block_rsv;
6396                 }
6397         }
6398         btrfs_release_path(path);
6399         BUG_ON(err);
6400
6401         ret = btrfs_del_root(trans, tree_root, &root->root_key);
6402         BUG_ON(ret);
6403
6404         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
6405                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
6406                                            NULL, NULL);
6407                 BUG_ON(ret < 0);
6408                 if (ret > 0) {
6409                         /* if we fail to delete the orphan item this time
6410                          * around, it'll get picked up the next time.
6411                          *
6412                          * The most common failure here is just -ENOENT.
6413                          */
6414                         btrfs_del_orphan_item(trans, tree_root,
6415                                               root->root_key.objectid);
6416                 }
6417         }
6418
6419         if (root->in_radix) {
6420                 btrfs_free_fs_root(tree_root->fs_info, root);
6421         } else {
6422                 free_extent_buffer(root->node);
6423                 free_extent_buffer(root->commit_root);
6424                 kfree(root);
6425         }
6426 out:
6427         btrfs_end_transaction_throttle(trans, tree_root);
6428         kfree(wc);
6429         btrfs_free_path(path);
6430         return err;
6431 }
6432
6433 /*
6434  * drop subtree rooted at tree block 'node'.
6435  *
6436  * NOTE: this function will unlock and release tree block 'node'
6437  */
6438 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6439                         struct btrfs_root *root,
6440                         struct extent_buffer *node,
6441                         struct extent_buffer *parent)
6442 {
6443         struct btrfs_path *path;
6444         struct walk_control *wc;
6445         int level;
6446         int parent_level;
6447         int ret = 0;
6448         int wret;
6449
6450         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6451
6452         path = btrfs_alloc_path();
6453         if (!path)
6454                 return -ENOMEM;
6455
6456         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6457         if (!wc) {
6458                 btrfs_free_path(path);
6459                 return -ENOMEM;
6460         }
6461
6462         btrfs_assert_tree_locked(parent);
6463         parent_level = btrfs_header_level(parent);
6464         extent_buffer_get(parent);
6465         path->nodes[parent_level] = parent;
6466         path->slots[parent_level] = btrfs_header_nritems(parent);
6467
6468         btrfs_assert_tree_locked(node);
6469         level = btrfs_header_level(node);
6470         path->nodes[level] = node;
6471         path->slots[level] = 0;
6472         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6473
6474         wc->refs[parent_level] = 1;
6475         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6476         wc->level = level;
6477         wc->shared_level = -1;
6478         wc->stage = DROP_REFERENCE;
6479         wc->update_ref = 0;
6480         wc->keep_locks = 1;
6481         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6482
6483         while (1) {
6484                 wret = walk_down_tree(trans, root, path, wc);
6485                 if (wret < 0) {
6486                         ret = wret;
6487                         break;
6488                 }
6489
6490                 wret = walk_up_tree(trans, root, path, wc, parent_level);
6491                 if (wret < 0)
6492                         ret = wret;
6493                 if (wret != 0)
6494                         break;
6495         }
6496
6497         kfree(wc);
6498         btrfs_free_path(path);
6499         return ret;
6500 }
6501
6502 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
6503 {
6504         u64 num_devices;
6505         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
6506                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
6507
6508         /*
6509          * we add in the count of missing devices because we want
6510          * to make sure that any RAID levels on a degraded FS
6511          * continue to be honored.
6512          */
6513         num_devices = root->fs_info->fs_devices->rw_devices +
6514                 root->fs_info->fs_devices->missing_devices;
6515
6516         if (num_devices == 1) {
6517                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6518                 stripped = flags & ~stripped;
6519
6520                 /* turn raid0 into single device chunks */
6521                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
6522                         return stripped;
6523
6524                 /* turn mirroring into duplication */
6525                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
6526                              BTRFS_BLOCK_GROUP_RAID10))
6527                         return stripped | BTRFS_BLOCK_GROUP_DUP;
6528                 return flags;
6529         } else {
6530                 /* they already had raid on here, just return */
6531                 if (flags & stripped)
6532                         return flags;
6533
6534                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6535                 stripped = flags & ~stripped;
6536
6537                 /* switch duplicated blocks with raid1 */
6538                 if (flags & BTRFS_BLOCK_GROUP_DUP)
6539                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
6540
6541                 /* turn single device chunks into raid0 */
6542                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
6543         }
6544         return flags;
6545 }
6546
6547 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
6548 {
6549         struct btrfs_space_info *sinfo = cache->space_info;
6550         u64 num_bytes;
6551         u64 min_allocable_bytes;
6552         int ret = -ENOSPC;
6553
6554
6555         /*
6556          * We need some metadata space and system metadata space for
6557          * allocating chunks in some corner cases until we force to set
6558          * it to be readonly.
6559          */
6560         if ((sinfo->flags &
6561              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
6562             !force)
6563                 min_allocable_bytes = 1 * 1024 * 1024;
6564         else
6565                 min_allocable_bytes = 0;
6566
6567         spin_lock(&sinfo->lock);
6568         spin_lock(&cache->lock);
6569
6570         if (cache->ro) {
6571                 ret = 0;
6572                 goto out;
6573         }
6574
6575         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
6576                     cache->bytes_super - btrfs_block_group_used(&cache->item);
6577
6578         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
6579             sinfo->bytes_may_use + sinfo->bytes_readonly +
6580             cache->reserved_pinned + num_bytes + min_allocable_bytes <=
6581             sinfo->total_bytes) {
6582                 sinfo->bytes_readonly += num_bytes;
6583                 sinfo->bytes_reserved += cache->reserved_pinned;
6584                 cache->reserved_pinned = 0;
6585                 cache->ro = 1;
6586                 ret = 0;
6587         }
6588 out:
6589         spin_unlock(&cache->lock);
6590         spin_unlock(&sinfo->lock);
6591         return ret;
6592 }
6593
6594 int btrfs_set_block_group_ro(struct btrfs_root *root,
6595                              struct btrfs_block_group_cache *cache)
6596
6597 {
6598         struct btrfs_trans_handle *trans;
6599         u64 alloc_flags;
6600         int ret;
6601
6602         BUG_ON(cache->ro);
6603
6604         trans = btrfs_join_transaction(root);
6605         BUG_ON(IS_ERR(trans));
6606
6607         alloc_flags = update_block_group_flags(root, cache->flags);
6608         if (alloc_flags != cache->flags)
6609                 do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6610                                CHUNK_ALLOC_FORCE);
6611
6612         ret = set_block_group_ro(cache, 0);
6613         if (!ret)
6614                 goto out;
6615         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
6616         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6617                              CHUNK_ALLOC_FORCE);
6618         if (ret < 0)
6619                 goto out;
6620         ret = set_block_group_ro(cache, 0);
6621 out:
6622         btrfs_end_transaction(trans, root);
6623         return ret;
6624 }
6625
6626 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
6627                             struct btrfs_root *root, u64 type)
6628 {
6629         u64 alloc_flags = get_alloc_profile(root, type);
6630         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6631                               CHUNK_ALLOC_FORCE);
6632 }
6633
6634 /*
6635  * helper to account the unused space of all the readonly block group in the
6636  * list. takes mirrors into account.
6637  */
6638 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
6639 {
6640         struct btrfs_block_group_cache *block_group;
6641         u64 free_bytes = 0;
6642         int factor;
6643
6644         list_for_each_entry(block_group, groups_list, list) {
6645                 spin_lock(&block_group->lock);
6646
6647                 if (!block_group->ro) {
6648                         spin_unlock(&block_group->lock);
6649                         continue;
6650                 }
6651
6652                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
6653                                           BTRFS_BLOCK_GROUP_RAID10 |
6654                                           BTRFS_BLOCK_GROUP_DUP))
6655                         factor = 2;
6656                 else
6657                         factor = 1;
6658
6659                 free_bytes += (block_group->key.offset -
6660                                btrfs_block_group_used(&block_group->item)) *
6661                                factor;
6662
6663                 spin_unlock(&block_group->lock);
6664         }
6665
6666         return free_bytes;
6667 }
6668
6669 /*
6670  * helper to account the unused space of all the readonly block group in the
6671  * space_info. takes mirrors into account.
6672  */
6673 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
6674 {
6675         int i;
6676         u64 free_bytes = 0;
6677
6678         spin_lock(&sinfo->lock);
6679
6680         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
6681                 if (!list_empty(&sinfo->block_groups[i]))
6682                         free_bytes += __btrfs_get_ro_block_group_free_space(
6683                                                 &sinfo->block_groups[i]);
6684
6685         spin_unlock(&sinfo->lock);
6686
6687         return free_bytes;
6688 }
6689
6690 int btrfs_set_block_group_rw(struct btrfs_root *root,
6691                               struct btrfs_block_group_cache *cache)
6692 {
6693         struct btrfs_space_info *sinfo = cache->space_info;
6694         u64 num_bytes;
6695
6696         BUG_ON(!cache->ro);
6697
6698         spin_lock(&sinfo->lock);
6699         spin_lock(&cache->lock);
6700         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
6701                     cache->bytes_super - btrfs_block_group_used(&cache->item);
6702         sinfo->bytes_readonly -= num_bytes;
6703         cache->ro = 0;
6704         spin_unlock(&cache->lock);
6705         spin_unlock(&sinfo->lock);
6706         return 0;
6707 }
6708
6709 /*
6710  * checks to see if its even possible to relocate this block group.
6711  *
6712  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
6713  * ok to go ahead and try.
6714  */
6715 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
6716 {
6717         struct btrfs_block_group_cache *block_group;
6718         struct btrfs_space_info *space_info;
6719         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6720         struct btrfs_device *device;
6721         int full = 0;
6722         int ret = 0;
6723
6724         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
6725
6726         /* odd, couldn't find the block group, leave it alone */
6727         if (!block_group)
6728                 return -1;
6729
6730         /* no bytes used, we're good */
6731         if (!btrfs_block_group_used(&block_group->item))
6732                 goto out;
6733
6734         space_info = block_group->space_info;
6735         spin_lock(&space_info->lock);
6736
6737         full = space_info->full;
6738
6739         /*
6740          * if this is the last block group we have in this space, we can't
6741          * relocate it unless we're able to allocate a new chunk below.
6742          *
6743          * Otherwise, we need to make sure we have room in the space to handle
6744          * all of the extents from this block group.  If we can, we're good
6745          */
6746         if ((space_info->total_bytes != block_group->key.offset) &&
6747            (space_info->bytes_used + space_info->bytes_reserved +
6748             space_info->bytes_pinned + space_info->bytes_readonly +
6749             btrfs_block_group_used(&block_group->item) <
6750             space_info->total_bytes)) {
6751                 spin_unlock(&space_info->lock);
6752                 goto out;
6753         }
6754         spin_unlock(&space_info->lock);
6755
6756         /*
6757          * ok we don't have enough space, but maybe we have free space on our
6758          * devices to allocate new chunks for relocation, so loop through our
6759          * alloc devices and guess if we have enough space.  However, if we
6760          * were marked as full, then we know there aren't enough chunks, and we
6761          * can just return.
6762          */
6763         ret = -1;
6764         if (full)
6765                 goto out;
6766
6767         mutex_lock(&root->fs_info->chunk_mutex);
6768         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
6769                 u64 min_free = btrfs_block_group_used(&block_group->item);
6770                 u64 dev_offset;
6771
6772                 /*
6773                  * check to make sure we can actually find a chunk with enough
6774                  * space to fit our block group in.
6775                  */
6776                 if (device->total_bytes > device->bytes_used + min_free) {
6777                         ret = find_free_dev_extent(NULL, device, min_free,
6778                                                    &dev_offset, NULL);
6779                         if (!ret)
6780                                 break;
6781                         ret = -1;
6782                 }
6783         }
6784         mutex_unlock(&root->fs_info->chunk_mutex);
6785 out:
6786         btrfs_put_block_group(block_group);
6787         return ret;
6788 }
6789
6790 static int find_first_block_group(struct btrfs_root *root,
6791                 struct btrfs_path *path, struct btrfs_key *key)
6792 {
6793         int ret = 0;
6794         struct btrfs_key found_key;
6795         struct extent_buffer *leaf;
6796         int slot;
6797
6798         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
6799         if (ret < 0)
6800                 goto out;
6801
6802         while (1) {
6803                 slot = path->slots[0];
6804                 leaf = path->nodes[0];
6805                 if (slot >= btrfs_header_nritems(leaf)) {
6806                         ret = btrfs_next_leaf(root, path);
6807                         if (ret == 0)
6808                                 continue;
6809                         if (ret < 0)
6810                                 goto out;
6811                         break;
6812                 }
6813                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6814
6815                 if (found_key.objectid >= key->objectid &&
6816                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
6817                         ret = 0;
6818                         goto out;
6819                 }
6820                 path->slots[0]++;
6821         }
6822 out:
6823         return ret;
6824 }
6825
6826 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
6827 {
6828         struct btrfs_block_group_cache *block_group;
6829         u64 last = 0;
6830
6831         while (1) {
6832                 struct inode *inode;
6833
6834                 block_group = btrfs_lookup_first_block_group(info, last);
6835                 while (block_group) {
6836                         spin_lock(&block_group->lock);
6837                         if (block_group->iref)
6838                                 break;
6839                         spin_unlock(&block_group->lock);
6840                         block_group = next_block_group(info->tree_root,
6841                                                        block_group);
6842                 }
6843                 if (!block_group) {
6844                         if (last == 0)
6845                                 break;
6846                         last = 0;
6847                         continue;
6848                 }
6849
6850                 inode = block_group->inode;
6851                 block_group->iref = 0;
6852                 block_group->inode = NULL;
6853                 spin_unlock(&block_group->lock);
6854                 iput(inode);
6855                 last = block_group->key.objectid + block_group->key.offset;
6856                 btrfs_put_block_group(block_group);
6857         }
6858 }
6859
6860 int btrfs_free_block_groups(struct btrfs_fs_info *info)
6861 {
6862         struct btrfs_block_group_cache *block_group;
6863         struct btrfs_space_info *space_info;
6864         struct btrfs_caching_control *caching_ctl;
6865         struct rb_node *n;
6866
6867         down_write(&info->extent_commit_sem);
6868         while (!list_empty(&info->caching_block_groups)) {
6869                 caching_ctl = list_entry(info->caching_block_groups.next,
6870                                          struct btrfs_caching_control, list);
6871                 list_del(&caching_ctl->list);
6872                 put_caching_control(caching_ctl);
6873         }
6874         up_write(&info->extent_commit_sem);
6875
6876         spin_lock(&info->block_group_cache_lock);
6877         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
6878                 block_group = rb_entry(n, struct btrfs_block_group_cache,
6879                                        cache_node);
6880                 rb_erase(&block_group->cache_node,
6881                          &info->block_group_cache_tree);
6882                 spin_unlock(&info->block_group_cache_lock);
6883
6884                 down_write(&block_group->space_info->groups_sem);
6885                 list_del(&block_group->list);
6886                 up_write(&block_group->space_info->groups_sem);
6887
6888                 if (block_group->cached == BTRFS_CACHE_STARTED)
6889                         wait_block_group_cache_done(block_group);
6890
6891                 /*
6892                  * We haven't cached this block group, which means we could
6893                  * possibly have excluded extents on this block group.
6894                  */
6895                 if (block_group->cached == BTRFS_CACHE_NO)
6896                         free_excluded_extents(info->extent_root, block_group);
6897
6898                 btrfs_remove_free_space_cache(block_group);
6899                 btrfs_put_block_group(block_group);
6900
6901                 spin_lock(&info->block_group_cache_lock);
6902         }
6903         spin_unlock(&info->block_group_cache_lock);
6904
6905         /* now that all the block groups are freed, go through and
6906          * free all the space_info structs.  This is only called during
6907          * the final stages of unmount, and so we know nobody is
6908          * using them.  We call synchronize_rcu() once before we start,
6909          * just to be on the safe side.
6910          */
6911         synchronize_rcu();
6912
6913         release_global_block_rsv(info);
6914
6915         while(!list_empty(&info->space_info)) {
6916                 space_info = list_entry(info->space_info.next,
6917                                         struct btrfs_space_info,
6918                                         list);
6919                 if (space_info->bytes_pinned > 0 ||
6920                     space_info->bytes_reserved > 0) {
6921                         WARN_ON(1);
6922                         dump_space_info(space_info, 0, 0);
6923                 }
6924                 list_del(&space_info->list);
6925                 kfree(space_info);
6926         }
6927         return 0;
6928 }
6929
6930 static void __link_block_group(struct btrfs_space_info *space_info,
6931                                struct btrfs_block_group_cache *cache)
6932 {
6933         int index = get_block_group_index(cache);
6934
6935         down_write(&space_info->groups_sem);
6936         list_add_tail(&cache->list, &space_info->block_groups[index]);
6937         up_write(&space_info->groups_sem);
6938 }
6939
6940 int btrfs_read_block_groups(struct btrfs_root *root)
6941 {
6942         struct btrfs_path *path;
6943         int ret;
6944         struct btrfs_block_group_cache *cache;
6945         struct btrfs_fs_info *info = root->fs_info;
6946         struct btrfs_space_info *space_info;
6947         struct btrfs_key key;
6948         struct btrfs_key found_key;
6949         struct extent_buffer *leaf;
6950         int need_clear = 0;
6951         u64 cache_gen;
6952
6953         root = info->extent_root;
6954         key.objectid = 0;
6955         key.offset = 0;
6956         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
6957         path = btrfs_alloc_path();
6958         if (!path)
6959                 return -ENOMEM;
6960         path->reada = 1;
6961
6962         cache_gen = btrfs_super_cache_generation(&root->fs_info->super_copy);
6963         if (cache_gen != 0 &&
6964             btrfs_super_generation(&root->fs_info->super_copy) != cache_gen)
6965                 need_clear = 1;
6966         if (btrfs_test_opt(root, CLEAR_CACHE))
6967                 need_clear = 1;
6968         if (!btrfs_test_opt(root, SPACE_CACHE) && cache_gen)
6969                 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
6970
6971         while (1) {
6972                 ret = find_first_block_group(root, path, &key);
6973                 if (ret > 0)
6974                         break;
6975                 if (ret != 0)
6976                         goto error;
6977                 leaf = path->nodes[0];
6978                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6979                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
6980                 if (!cache) {
6981                         ret = -ENOMEM;
6982                         goto error;
6983                 }
6984                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
6985                                                 GFP_NOFS);
6986                 if (!cache->free_space_ctl) {
6987                         kfree(cache);
6988                         ret = -ENOMEM;
6989                         goto error;
6990                 }
6991
6992                 atomic_set(&cache->count, 1);
6993                 spin_lock_init(&cache->lock);
6994                 cache->fs_info = info;
6995                 INIT_LIST_HEAD(&cache->list);
6996                 INIT_LIST_HEAD(&cache->cluster_list);
6997
6998                 if (need_clear)
6999                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7000
7001                 read_extent_buffer(leaf, &cache->item,
7002                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7003                                    sizeof(cache->item));
7004                 memcpy(&cache->key, &found_key, sizeof(found_key));
7005
7006                 key.objectid = found_key.objectid + found_key.offset;
7007                 btrfs_release_path(path);
7008                 cache->flags = btrfs_block_group_flags(&cache->item);
7009                 cache->sectorsize = root->sectorsize;
7010
7011                 btrfs_init_free_space_ctl(cache);
7012
7013                 /*
7014                  * We need to exclude the super stripes now so that the space
7015                  * info has super bytes accounted for, otherwise we'll think
7016                  * we have more space than we actually do.
7017                  */
7018                 exclude_super_stripes(root, cache);
7019
7020                 /*
7021                  * check for two cases, either we are full, and therefore
7022                  * don't need to bother with the caching work since we won't
7023                  * find any space, or we are empty, and we can just add all
7024                  * the space in and be done with it.  This saves us _alot_ of
7025                  * time, particularly in the full case.
7026                  */
7027                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7028                         cache->last_byte_to_unpin = (u64)-1;
7029                         cache->cached = BTRFS_CACHE_FINISHED;
7030                         free_excluded_extents(root, cache);
7031                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7032                         cache->last_byte_to_unpin = (u64)-1;
7033                         cache->cached = BTRFS_CACHE_FINISHED;
7034                         add_new_free_space(cache, root->fs_info,
7035                                            found_key.objectid,
7036                                            found_key.objectid +
7037                                            found_key.offset);
7038                         free_excluded_extents(root, cache);
7039                 }
7040
7041                 ret = update_space_info(info, cache->flags, found_key.offset,
7042                                         btrfs_block_group_used(&cache->item),
7043                                         &space_info);
7044                 BUG_ON(ret);
7045                 cache->space_info = space_info;
7046                 spin_lock(&cache->space_info->lock);
7047                 cache->space_info->bytes_readonly += cache->bytes_super;
7048                 spin_unlock(&cache->space_info->lock);
7049
7050                 __link_block_group(space_info, cache);
7051
7052                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7053                 BUG_ON(ret);
7054
7055                 set_avail_alloc_bits(root->fs_info, cache->flags);
7056                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7057                         set_block_group_ro(cache, 1);
7058         }
7059
7060         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7061                 if (!(get_alloc_profile(root, space_info->flags) &
7062                       (BTRFS_BLOCK_GROUP_RAID10 |
7063                        BTRFS_BLOCK_GROUP_RAID1 |
7064                        BTRFS_BLOCK_GROUP_DUP)))
7065                         continue;
7066                 /*
7067                  * avoid allocating from un-mirrored block group if there are
7068                  * mirrored block groups.
7069                  */
7070                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7071                         set_block_group_ro(cache, 1);
7072                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7073                         set_block_group_ro(cache, 1);
7074         }
7075
7076         init_global_block_rsv(info);
7077         ret = 0;
7078 error:
7079         btrfs_free_path(path);
7080         return ret;
7081 }
7082
7083 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7084                            struct btrfs_root *root, u64 bytes_used,
7085                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7086                            u64 size)
7087 {
7088         int ret;
7089         struct btrfs_root *extent_root;
7090         struct btrfs_block_group_cache *cache;
7091
7092         extent_root = root->fs_info->extent_root;
7093
7094         root->fs_info->last_trans_log_full_commit = trans->transid;
7095
7096         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7097         if (!cache)
7098                 return -ENOMEM;
7099         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7100                                         GFP_NOFS);
7101         if (!cache->free_space_ctl) {
7102                 kfree(cache);
7103                 return -ENOMEM;
7104         }
7105
7106         cache->key.objectid = chunk_offset;
7107         cache->key.offset = size;
7108         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7109         cache->sectorsize = root->sectorsize;
7110         cache->fs_info = root->fs_info;
7111
7112         atomic_set(&cache->count, 1);
7113         spin_lock_init(&cache->lock);
7114         INIT_LIST_HEAD(&cache->list);
7115         INIT_LIST_HEAD(&cache->cluster_list);
7116
7117         btrfs_init_free_space_ctl(cache);
7118
7119         btrfs_set_block_group_used(&cache->item, bytes_used);
7120         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7121         cache->flags = type;
7122         btrfs_set_block_group_flags(&cache->item, type);
7123
7124         cache->last_byte_to_unpin = (u64)-1;
7125         cache->cached = BTRFS_CACHE_FINISHED;
7126         exclude_super_stripes(root, cache);
7127
7128         add_new_free_space(cache, root->fs_info, chunk_offset,
7129                            chunk_offset + size);
7130
7131         free_excluded_extents(root, cache);
7132
7133         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7134                                 &cache->space_info);
7135         BUG_ON(ret);
7136
7137         spin_lock(&cache->space_info->lock);
7138         cache->space_info->bytes_readonly += cache->bytes_super;
7139         spin_unlock(&cache->space_info->lock);
7140
7141         __link_block_group(cache->space_info, cache);
7142
7143         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7144         BUG_ON(ret);
7145
7146         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7147                                 sizeof(cache->item));
7148         BUG_ON(ret);
7149
7150         set_avail_alloc_bits(extent_root->fs_info, type);
7151
7152         return 0;
7153 }
7154
7155 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7156                              struct btrfs_root *root, u64 group_start)
7157 {
7158         struct btrfs_path *path;
7159         struct btrfs_block_group_cache *block_group;
7160         struct btrfs_free_cluster *cluster;
7161         struct btrfs_root *tree_root = root->fs_info->tree_root;
7162         struct btrfs_key key;
7163         struct inode *inode;
7164         int ret;
7165         int factor;
7166
7167         root = root->fs_info->extent_root;
7168
7169         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7170         BUG_ON(!block_group);
7171         BUG_ON(!block_group->ro);
7172
7173         /*
7174          * Free the reserved super bytes from this block group before
7175          * remove it.
7176          */
7177         free_excluded_extents(root, block_group);
7178
7179         memcpy(&key, &block_group->key, sizeof(key));
7180         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7181                                   BTRFS_BLOCK_GROUP_RAID1 |
7182                                   BTRFS_BLOCK_GROUP_RAID10))
7183                 factor = 2;
7184         else
7185                 factor = 1;
7186
7187         /* make sure this block group isn't part of an allocation cluster */
7188         cluster = &root->fs_info->data_alloc_cluster;
7189         spin_lock(&cluster->refill_lock);
7190         btrfs_return_cluster_to_free_space(block_group, cluster);
7191         spin_unlock(&cluster->refill_lock);
7192
7193         /*
7194          * make sure this block group isn't part of a metadata
7195          * allocation cluster
7196          */
7197         cluster = &root->fs_info->meta_alloc_cluster;
7198         spin_lock(&cluster->refill_lock);
7199         btrfs_return_cluster_to_free_space(block_group, cluster);
7200         spin_unlock(&cluster->refill_lock);
7201
7202         path = btrfs_alloc_path();
7203         if (!path) {
7204                 ret = -ENOMEM;
7205                 goto out;
7206         }
7207
7208         inode = lookup_free_space_inode(root, block_group, path);
7209         if (!IS_ERR(inode)) {
7210                 ret = btrfs_orphan_add(trans, inode);
7211                 BUG_ON(ret);
7212                 clear_nlink(inode);
7213                 /* One for the block groups ref */
7214                 spin_lock(&block_group->lock);
7215                 if (block_group->iref) {
7216                         block_group->iref = 0;
7217                         block_group->inode = NULL;
7218                         spin_unlock(&block_group->lock);
7219                         iput(inode);
7220                 } else {
7221                         spin_unlock(&block_group->lock);
7222                 }
7223                 /* One for our lookup ref */
7224                 iput(inode);
7225         }
7226
7227         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7228         key.offset = block_group->key.objectid;
7229         key.type = 0;
7230
7231         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7232         if (ret < 0)
7233                 goto out;
7234         if (ret > 0)
7235                 btrfs_release_path(path);
7236         if (ret == 0) {
7237                 ret = btrfs_del_item(trans, tree_root, path);
7238                 if (ret)
7239                         goto out;
7240                 btrfs_release_path(path);
7241         }
7242
7243         spin_lock(&root->fs_info->block_group_cache_lock);
7244         rb_erase(&block_group->cache_node,
7245                  &root->fs_info->block_group_cache_tree);
7246         spin_unlock(&root->fs_info->block_group_cache_lock);
7247
7248         down_write(&block_group->space_info->groups_sem);
7249         /*
7250          * we must use list_del_init so people can check to see if they
7251          * are still on the list after taking the semaphore
7252          */
7253         list_del_init(&block_group->list);
7254         up_write(&block_group->space_info->groups_sem);
7255
7256         if (block_group->cached == BTRFS_CACHE_STARTED)
7257                 wait_block_group_cache_done(block_group);
7258
7259         btrfs_remove_free_space_cache(block_group);
7260
7261         spin_lock(&block_group->space_info->lock);
7262         block_group->space_info->total_bytes -= block_group->key.offset;
7263         block_group->space_info->bytes_readonly -= block_group->key.offset;
7264         block_group->space_info->disk_total -= block_group->key.offset * factor;
7265         spin_unlock(&block_group->space_info->lock);
7266
7267         memcpy(&key, &block_group->key, sizeof(key));
7268
7269         btrfs_clear_space_info_full(root->fs_info);
7270
7271         btrfs_put_block_group(block_group);
7272         btrfs_put_block_group(block_group);
7273
7274         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
7275         if (ret > 0)
7276                 ret = -EIO;
7277         if (ret < 0)
7278                 goto out;
7279
7280         ret = btrfs_del_item(trans, root, path);
7281 out:
7282         btrfs_free_path(path);
7283         return ret;
7284 }
7285
7286 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
7287 {
7288         struct btrfs_space_info *space_info;
7289         struct btrfs_super_block *disk_super;
7290         u64 features;
7291         u64 flags;
7292         int mixed = 0;
7293         int ret;
7294
7295         disk_super = &fs_info->super_copy;
7296         if (!btrfs_super_root(disk_super))
7297                 return 1;
7298
7299         features = btrfs_super_incompat_flags(disk_super);
7300         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
7301                 mixed = 1;
7302
7303         flags = BTRFS_BLOCK_GROUP_SYSTEM;
7304         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7305         if (ret)
7306                 goto out;
7307
7308         if (mixed) {
7309                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
7310                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7311         } else {
7312                 flags = BTRFS_BLOCK_GROUP_METADATA;
7313                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7314                 if (ret)
7315                         goto out;
7316
7317                 flags = BTRFS_BLOCK_GROUP_DATA;
7318                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7319         }
7320 out:
7321         return ret;
7322 }
7323
7324 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
7325 {
7326         return unpin_extent_range(root, start, end);
7327 }
7328
7329 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
7330                                u64 num_bytes, u64 *actual_bytes)
7331 {
7332         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
7333 }
7334
7335 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
7336 {
7337         struct btrfs_fs_info *fs_info = root->fs_info;
7338         struct btrfs_block_group_cache *cache = NULL;
7339         u64 group_trimmed;
7340         u64 start;
7341         u64 end;
7342         u64 trimmed = 0;
7343         int ret = 0;
7344
7345         cache = btrfs_lookup_block_group(fs_info, range->start);
7346
7347         while (cache) {
7348                 if (cache->key.objectid >= (range->start + range->len)) {
7349                         btrfs_put_block_group(cache);
7350                         break;
7351                 }
7352
7353                 start = max(range->start, cache->key.objectid);
7354                 end = min(range->start + range->len,
7355                                 cache->key.objectid + cache->key.offset);
7356
7357                 if (end - start >= range->minlen) {
7358                         if (!block_group_cache_done(cache)) {
7359                                 ret = cache_block_group(cache, NULL, root, 0);
7360                                 if (!ret)
7361                                         wait_block_group_cache_done(cache);
7362                         }
7363                         ret = btrfs_trim_block_group(cache,
7364                                                      &group_trimmed,
7365                                                      start,
7366                                                      end,
7367                                                      range->minlen);
7368
7369                         trimmed += group_trimmed;
7370                         if (ret) {
7371                                 btrfs_put_block_group(cache);
7372                                 break;
7373                         }
7374                 }
7375
7376                 cache = next_block_group(fs_info->tree_root, cache);
7377         }
7378
7379         range->len = trimmed;
7380         return ret;
7381 }