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