fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include "compat.h"
  28 #include "hash.h"
  29 #include "ctree.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "transaction.h"
  33 #include "volumes.h"
  34 #include "raid56.h"
  35 #include "locking.h"
  36 #include "free-space-cache.h"
  37 #include "math.h"
  38
  39 #undef SCRAMBLE_DELAYED_REFS
  40
  41 /*
  42  * control flags for do_chunk_alloc's force field
  43  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  44  * if we really need one.
  45  *
  46  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  47  * if we have very few chunks already allocated.  This is
  48  * used as part of the clustering code to help make sure
  49  * we have a good pool of storage to cluster in, without
  50  * filling the FS with empty chunks
  51  *
  52  * CHUNK_ALLOC_FORCE means it must try to allocate one
  53  *
  54  */
  55 enum {
  56         CHUNK_ALLOC_NO_FORCE = 0,
  57         CHUNK_ALLOC_LIMITED = 1,
  58         CHUNK_ALLOC_FORCE = 2,
  59 };
  60
  61 /*
  62  * Control how reservations are dealt with.
  63  *
  64  * RESERVE_FREE - freeing a reservation.
  65  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  66  *   ENOSPC accounting
  67  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  68  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  69  */
  70 enum {
  71         RESERVE_FREE = 0,
  72         RESERVE_ALLOC = 1,
  73         RESERVE_ALLOC_NO_ACCOUNT = 2,
  74 };
  75
  76 static int update_block_group(struct btrfs_root *root,
  77                               u64 bytenr, u64 num_bytes, int alloc);
  78 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  79                                 struct btrfs_root *root,
  80                                 u64 bytenr, u64 num_bytes, u64 parent,
  81                                 u64 root_objectid, u64 owner_objectid,
  82                                 u64 owner_offset, int refs_to_drop,
  83                                 struct btrfs_delayed_extent_op *extra_op);
  84 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  85                                     struct extent_buffer *leaf,
  86                                     struct btrfs_extent_item *ei);
  87 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  88                                       struct btrfs_root *root,
  89                                       u64 parent, u64 root_objectid,
  90                                       u64 flags, u64 owner, u64 offset,
  91                                       struct btrfs_key *ins, int ref_mod);
  92 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  93                                      struct btrfs_root *root,
  94                                      u64 parent, u64 root_objectid,
  95                                      u64 flags, struct btrfs_disk_key *key,
  96                                      int level, struct btrfs_key *ins);
  97 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  98                           struct btrfs_root *extent_root, u64 flags,
  99                           int force);
 100 static int find_next_key(struct btrfs_path *path, int level,
 101                          struct btrfs_key *key);
 102 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 103                             int dump_block_groups);
 104 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 105                                        u64 num_bytes, int reserve);
 106 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 107                                u64 num_bytes);
 108
 109 static noinline int
 110 block_group_cache_done(struct btrfs_block_group_cache *cache)
 111 {
 112         smp_mb();
 113         return cache->cached == BTRFS_CACHE_FINISHED;
 114 }
 115
 116 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 117 {
 118         return (cache->flags & bits) == bits;
 119 }
 120
 121 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 122 {
 123         atomic_inc(&cache->count);
 124 }
 125
 126 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 127 {
 128         if (atomic_dec_and_test(&cache->count)) {
 129                 WARN_ON(cache->pinned > 0);
 130                 WARN_ON(cache->reserved > 0);
 131                 kfree(cache->free_space_ctl);
 132                 kfree(cache);
 133         }
 134 }
 135
 136 /*
 137  * this adds the block group to the fs_info rb tree for the block group
 138  * cache
 139  */
 140 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 141                                 struct btrfs_block_group_cache *block_group)
 142 {
 143         struct rb_node **p;
 144         struct rb_node *parent = NULL;
 145         struct btrfs_block_group_cache *cache;
 146
 147         spin_lock(&info->block_group_cache_lock);
 148         p = &info->block_group_cache_tree.rb_node;
 149
 150         while (*p) {
 151                 parent = *p;
 152                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 153                                  cache_node);
 154                 if (block_group->key.objectid < cache->key.objectid) {
 155                         p = &(*p)->rb_left;
 156                 } else if (block_group->key.objectid > cache->key.objectid) {
 157                         p = &(*p)->rb_right;
 158                 } else {
 159                         spin_unlock(&info->block_group_cache_lock);
 160                         return -EEXIST;
 161                 }
 162         }
 163
 164         rb_link_node(&block_group->cache_node, parent, p);
 165         rb_insert_color(&block_group->cache_node,
 166                         &info->block_group_cache_tree);
 167
 168         if (info->first_logical_byte > block_group->key.objectid)
 169                 info->first_logical_byte = block_group->key.objectid;
 170
 171         spin_unlock(&info->block_group_cache_lock);
 172
 173         return 0;
 174 }
 175
 176 /*
 177  * This will return the block group at or after bytenr if contains is 0, else
 178  * it will return the block group that contains the bytenr
 179  */
 180 static struct btrfs_block_group_cache *
 181 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 182                               int contains)
 183 {
 184         struct btrfs_block_group_cache *cache, *ret = NULL;
 185         struct rb_node *n;
 186         u64 end, start;
 187
 188         spin_lock(&info->block_group_cache_lock);
 189         n = info->block_group_cache_tree.rb_node;
 190
 191         while (n) {
 192                 cache = rb_entry(n, struct btrfs_block_group_cache,
 193                                  cache_node);
 194                 end = cache->key.objectid + cache->key.offset - 1;
 195                 start = cache->key.objectid;
 196
 197                 if (bytenr < start) {
 198                         if (!contains && (!ret || start < ret->key.objectid))
 199                                 ret = cache;
 200                         n = n->rb_left;
 201                 } else if (bytenr > start) {
 202                         if (contains && bytenr <= end) {
 203                                 ret = cache;
 204                                 break;
 205                         }
 206                         n = n->rb_right;
 207                 } else {
 208                         ret = cache;
 209                         break;
 210                 }
 211         }
 212         if (ret) {
 213                 btrfs_get_block_group(ret);
 214                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 215                         info->first_logical_byte = ret->key.objectid;
 216         }
 217         spin_unlock(&info->block_group_cache_lock);
 218
 219         return ret;
 220 }
 221
 222 static int add_excluded_extent(struct btrfs_root *root,
 223                                u64 start, u64 num_bytes)
 224 {
 225         u64 end = start + num_bytes - 1;
 226         set_extent_bits(&root->fs_info->freed_extents[0],
 227                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 228         set_extent_bits(&root->fs_info->freed_extents[1],
 229                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 230         return 0;
 231 }
 232
 233 static void free_excluded_extents(struct btrfs_root *root,
 234                                   struct btrfs_block_group_cache *cache)
 235 {
 236         u64 start, end;
 237
 238         start = cache->key.objectid;
 239         end = start + cache->key.offset - 1;
 240
 241         clear_extent_bits(&root->fs_info->freed_extents[0],
 242                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 243         clear_extent_bits(&root->fs_info->freed_extents[1],
 244                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 245 }
 246
 247 static int exclude_super_stripes(struct btrfs_root *root,
 248                                  struct btrfs_block_group_cache *cache)
 249 {
 250         u64 bytenr;
 251         u64 *logical;
 252         int stripe_len;
 253         int i, nr, ret;
 254
 255         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 256                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 257                 cache->bytes_super += stripe_len;
 258                 ret = add_excluded_extent(root, cache->key.objectid,
 259                                           stripe_len);
 260                 if (ret)
 261                         return ret;
 262         }
 263
 264         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 265                 bytenr = btrfs_sb_offset(i);
 266                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 267                                        cache->key.objectid, bytenr,
 268                                        0, &logical, &nr, &stripe_len);
 269                 if (ret)
 270                         return ret;
 271
 272                 while (nr--) {
 273                         cache->bytes_super += stripe_len;
 274                         ret = add_excluded_extent(root, logical[nr],
 275                                                   stripe_len);
 276                         if (ret) {
 277                                 kfree(logical);
 278                                 return ret;
 279                         }
 280                 }
 281
 282                 kfree(logical);
 283         }
 284         return 0;
 285 }
 286
 287 static struct btrfs_caching_control *
 288 get_caching_control(struct btrfs_block_group_cache *cache)
 289 {
 290         struct btrfs_caching_control *ctl;
 291
 292         spin_lock(&cache->lock);
 293         if (cache->cached != BTRFS_CACHE_STARTED) {
 294                 spin_unlock(&cache->lock);
 295                 return NULL;
 296         }
 297
 298         /* We're loading it the fast way, so we don't have a caching_ctl. */
 299         if (!cache->caching_ctl) {
 300                 spin_unlock(&cache->lock);
 301                 return NULL;
 302         }
 303
 304         ctl = cache->caching_ctl;
 305         atomic_inc(&ctl->count);
 306         spin_unlock(&cache->lock);
 307         return ctl;
 308 }
 309
 310 static void put_caching_control(struct btrfs_caching_control *ctl)
 311 {
 312         if (atomic_dec_and_test(&ctl->count))
 313                 kfree(ctl);
 314 }
 315
 316 /*
 317  * this is only called by cache_block_group, since we could have freed extents
 318  * we need to check the pinned_extents for any extents that can't be used yet
 319  * since their free space will be released as soon as the transaction commits.
 320  */
 321 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 322                               struct btrfs_fs_info *info, u64 start, u64 end)
 323 {
 324         u64 extent_start, extent_end, size, total_added = 0;
 325         int ret;
 326
 327         while (start < end) {
 328                 ret = find_first_extent_bit(info->pinned_extents, start,
 329                                             &extent_start, &extent_end,
 330                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 331                                             NULL);
 332                 if (ret)
 333                         break;
 334
 335                 if (extent_start <= start) {
 336                         start = extent_end + 1;
 337                 } else if (extent_start > start && extent_start < end) {
 338                         size = extent_start - start;
 339                         total_added += size;
 340                         ret = btrfs_add_free_space(block_group, start,
 341                                                    size);
 342                         BUG_ON(ret); /* -ENOMEM or logic error */
 343                         start = extent_end + 1;
 344                 } else {
 345                         break;
 346                 }
 347         }
 348
 349         if (start < end) {
 350                 size = end - start;
 351                 total_added += size;
 352                 ret = btrfs_add_free_space(block_group, start, size);
 353                 BUG_ON(ret); /* -ENOMEM or logic error */
 354         }
 355
 356         return total_added;
 357 }
 358
 359 static noinline void caching_thread(struct btrfs_work *work)
 360 {
 361         struct btrfs_block_group_cache *block_group;
 362         struct btrfs_fs_info *fs_info;
 363         struct btrfs_caching_control *caching_ctl;
 364         struct btrfs_root *extent_root;
 365         struct btrfs_path *path;
 366         struct extent_buffer *leaf;
 367         struct btrfs_key key;
 368         u64 total_found = 0;
 369         u64 last = 0;
 370         u32 nritems;
 371         int ret = 0;
 372
 373         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 374         block_group = caching_ctl->block_group;
 375         fs_info = block_group->fs_info;
 376         extent_root = fs_info->extent_root;
 377
 378         path = btrfs_alloc_path();
 379         if (!path)
 380                 goto out;
 381
 382         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 383
 384         /*
 385          * We don't want to deadlock with somebody trying to allocate a new
 386          * extent for the extent root while also trying to search the extent
 387          * root to add free space.  So we skip locking and search the commit
 388          * root, since its read-only
 389          */
 390         path->skip_locking = 1;
 391         path->search_commit_root = 1;
 392         path->reada = 1;
 393
 394         key.objectid = last;
 395         key.offset = 0;
 396         key.type = BTRFS_EXTENT_ITEM_KEY;
 397 again:
 398         mutex_lock(&caching_ctl->mutex);
 399         /* need to make sure the commit_root doesn't disappear */
 400         down_read(&fs_info->extent_commit_sem);
 401
 402         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 403         if (ret < 0)
 404                 goto err;
 405
 406         leaf = path->nodes[0];
 407         nritems = btrfs_header_nritems(leaf);
 408
 409         while (1) {
 410                 if (btrfs_fs_closing(fs_info) > 1) {
 411                         last = (u64)-1;
 412                         break;
 413                 }
 414
 415                 if (path->slots[0] < nritems) {
 416                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 417                 } else {
 418                         ret = find_next_key(path, 0, &key);
 419                         if (ret)
 420                                 break;
 421
 422                         if (need_resched() ||
 423                             btrfs_next_leaf(extent_root, path)) {
 424                                 caching_ctl->progress = last;
 425                                 btrfs_release_path(path);
 426                                 up_read(&fs_info->extent_commit_sem);
 427                                 mutex_unlock(&caching_ctl->mutex);
 428                                 cond_resched();
 429                                 goto again;
 430                         }
 431                         leaf = path->nodes[0];
 432                         nritems = btrfs_header_nritems(leaf);
 433                         continue;
 434                 }
 435
 436                 if (key.objectid < block_group->key.objectid) {
 437                         path->slots[0]++;
 438                         continue;
 439                 }
 440
 441                 if (key.objectid >= block_group->key.objectid +
 442                     block_group->key.offset)
 443                         break;
 444
 445                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 446                         total_found += add_new_free_space(block_group,
 447                                                           fs_info, last,
 448                                                           key.objectid);
 449                         last = key.objectid + key.offset;
 450
 451                         if (total_found > (1024 * 1024 * 2)) {
 452                                 total_found = 0;
 453                                 wake_up(&caching_ctl->wait);
 454                         }
 455                 }
 456                 path->slots[0]++;
 457         }
 458         ret = 0;
 459
 460         total_found += add_new_free_space(block_group, fs_info, last,
 461                                           block_group->key.objectid +
 462                                           block_group->key.offset);
 463         caching_ctl->progress = (u64)-1;
 464
 465         spin_lock(&block_group->lock);
 466         block_group->caching_ctl = NULL;
 467         block_group->cached = BTRFS_CACHE_FINISHED;
 468         spin_unlock(&block_group->lock);
 469
 470 err:
 471         btrfs_free_path(path);
 472         up_read(&fs_info->extent_commit_sem);
 473
 474         free_excluded_extents(extent_root, block_group);
 475
 476         mutex_unlock(&caching_ctl->mutex);
 477 out:
 478         wake_up(&caching_ctl->wait);
 479
 480         put_caching_control(caching_ctl);
 481         btrfs_put_block_group(block_group);
 482 }
 483
 484 static int cache_block_group(struct btrfs_block_group_cache *cache,
 485                              int load_cache_only)
 486 {
 487         DEFINE_WAIT(wait);
 488         struct btrfs_fs_info *fs_info = cache->fs_info;
 489         struct btrfs_caching_control *caching_ctl;
 490         int ret = 0;
 491
 492         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 493         if (!caching_ctl)
 494                 return -ENOMEM;
 495
 496         INIT_LIST_HEAD(&caching_ctl->list);
 497         mutex_init(&caching_ctl->mutex);
 498         init_waitqueue_head(&caching_ctl->wait);
 499         caching_ctl->block_group = cache;
 500         caching_ctl->progress = cache->key.objectid;
 501         atomic_set(&caching_ctl->count, 1);
 502         caching_ctl->work.func = caching_thread;
 503
 504         spin_lock(&cache->lock);
 505         /*
 506          * This should be a rare occasion, but this could happen I think in the
 507          * case where one thread starts to load the space cache info, and then
 508          * some other thread starts a transaction commit which tries to do an
 509          * allocation while the other thread is still loading the space cache
 510          * info.  The previous loop should have kept us from choosing this block
 511          * group, but if we've moved to the state where we will wait on caching
 512          * block groups we need to first check if we're doing a fast load here,
 513          * so we can wait for it to finish, otherwise we could end up allocating
 514          * from a block group who's cache gets evicted for one reason or
 515          * another.
 516          */
 517         while (cache->cached == BTRFS_CACHE_FAST) {
 518                 struct btrfs_caching_control *ctl;
 519
 520                 ctl = cache->caching_ctl;
 521                 atomic_inc(&ctl->count);
 522                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 523                 spin_unlock(&cache->lock);
 524
 525                 schedule();
 526
 527                 finish_wait(&ctl->wait, &wait);
 528                 put_caching_control(ctl);
 529                 spin_lock(&cache->lock);
 530         }
 531
 532         if (cache->cached != BTRFS_CACHE_NO) {
 533                 spin_unlock(&cache->lock);
 534                 kfree(caching_ctl);
 535                 return 0;
 536         }
 537         WARN_ON(cache->caching_ctl);
 538         cache->caching_ctl = caching_ctl;
 539         cache->cached = BTRFS_CACHE_FAST;
 540         spin_unlock(&cache->lock);
 541
 542         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 543                 ret = load_free_space_cache(fs_info, cache);
 544
 545                 spin_lock(&cache->lock);
 546                 if (ret == 1) {
 547                         cache->caching_ctl = NULL;
 548                         cache->cached = BTRFS_CACHE_FINISHED;
 549                         cache->last_byte_to_unpin = (u64)-1;
 550                 } else {
 551                         if (load_cache_only) {
 552                                 cache->caching_ctl = NULL;
 553                                 cache->cached = BTRFS_CACHE_NO;
 554                         } else {
 555                                 cache->cached = BTRFS_CACHE_STARTED;
 556                         }
 557                 }
 558                 spin_unlock(&cache->lock);
 559                 wake_up(&caching_ctl->wait);
 560                 if (ret == 1) {
 561                         put_caching_control(caching_ctl);
 562                         free_excluded_extents(fs_info->extent_root, cache);
 563                         return 0;
 564                 }
 565         } else {
 566                 /*
 567                  * We are not going to do the fast caching, set cached to the
 568                  * appropriate value and wakeup any waiters.
 569                  */
 570                 spin_lock(&cache->lock);
 571                 if (load_cache_only) {
 572                         cache->caching_ctl = NULL;
 573                         cache->cached = BTRFS_CACHE_NO;
 574                 } else {
 575                         cache->cached = BTRFS_CACHE_STARTED;
 576                 }
 577                 spin_unlock(&cache->lock);
 578                 wake_up(&caching_ctl->wait);
 579         }
 580
 581         if (load_cache_only) {
 582                 put_caching_control(caching_ctl);
 583                 return 0;
 584         }
 585
 586         down_write(&fs_info->extent_commit_sem);
 587         atomic_inc(&caching_ctl->count);
 588         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 589         up_write(&fs_info->extent_commit_sem);
 590
 591         btrfs_get_block_group(cache);
 592
 593         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 594
 595         return ret;
 596 }
 597
 598 /*
 599  * return the block group that starts at or after bytenr
 600  */
 601 static struct btrfs_block_group_cache *
 602 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 603 {
 604         struct btrfs_block_group_cache *cache;
 605
 606         cache = block_group_cache_tree_search(info, bytenr, 0);
 607
 608         return cache;
 609 }
 610
 611 /*
 612  * return the block group that contains the given bytenr
 613  */
 614 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 615                                                  struct btrfs_fs_info *info,
 616                                                  u64 bytenr)
 617 {
 618         struct btrfs_block_group_cache *cache;
 619
 620         cache = block_group_cache_tree_search(info, bytenr, 1);
 621
 622         return cache;
 623 }
 624
 625 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 626                                                   u64 flags)
 627 {
 628         struct list_head *head = &info->space_info;
 629         struct btrfs_space_info *found;
 630
 631         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 632
 633         rcu_read_lock();
 634         list_for_each_entry_rcu(found, head, list) {
 635                 if (found->flags & flags) {
 636                         rcu_read_unlock();
 637                         return found;
 638                 }
 639         }
 640         rcu_read_unlock();
 641         return NULL;
 642 }
 643
 644 /*
 645  * after adding space to the filesystem, we need to clear the full flags
 646  * on all the space infos.
 647  */
 648 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 649 {
 650         struct list_head *head = &info->space_info;
 651         struct btrfs_space_info *found;
 652
 653         rcu_read_lock();
 654         list_for_each_entry_rcu(found, head, list)
 655                 found->full = 0;
 656         rcu_read_unlock();
 657 }
 658
 659 u64 btrfs_find_block_group(struct btrfs_root *root,
 660                            u64 search_start, u64 search_hint, int owner)
 661 {
 662         struct btrfs_block_group_cache *cache;
 663         u64 used;
 664         u64 last = max(search_hint, search_start);
 665         u64 group_start = 0;
 666         int full_search = 0;
 667         int factor = 9;
 668         int wrapped = 0;
 669 again:
 670         while (1) {
 671                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 672                 if (!cache)
 673                         break;
 674
 675                 spin_lock(&cache->lock);
 676                 last = cache->key.objectid + cache->key.offset;
 677                 used = btrfs_block_group_used(&cache->item);
 678
 679                 if ((full_search || !cache->ro) &&
 680                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 681                         if (used + cache->pinned + cache->reserved <
 682                             div_factor(cache->key.offset, factor)) {
 683                                 group_start = cache->key.objectid;
 684                                 spin_unlock(&cache->lock);
 685                                 btrfs_put_block_group(cache);
 686                                 goto found;
 687                         }
 688                 }
 689                 spin_unlock(&cache->lock);
 690                 btrfs_put_block_group(cache);
 691                 cond_resched();
 692         }
 693         if (!wrapped) {
 694                 last = search_start;
 695                 wrapped = 1;
 696                 goto again;
 697         }
 698         if (!full_search && factor < 10) {
 699                 last = search_start;
 700                 full_search = 1;
 701                 factor = 10;
 702                 goto again;
 703         }
 704 found:
 705         return group_start;
 706 }
 707
 708 /* simple helper to search for an existing extent at a given offset */
 709 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 710 {
 711         int ret;
 712         struct btrfs_key key;
 713         struct btrfs_path *path;
 714
 715         path = btrfs_alloc_path();
 716         if (!path)
 717                 return -ENOMEM;
 718
 719         key.objectid = start;
 720         key.offset = len;
 721         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 722         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 723                                 0, 0);
 724         btrfs_free_path(path);
 725         return ret;
 726 }
 727
 728 /*
 729  * helper function to lookup reference count and flags of extent.
 730  *
 731  * the head node for delayed ref is used to store the sum of all the
 732  * reference count modifications queued up in the rbtree. the head
 733  * node may also store the extent flags to set. This way you can check
 734  * to see what the reference count and extent flags would be if all of
 735  * the delayed refs are not processed.
 736  */
 737 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 738                              struct btrfs_root *root, u64 bytenr,
 739                              u64 num_bytes, u64 *refs, u64 *flags)
 740 {
 741         struct btrfs_delayed_ref_head *head;
 742         struct btrfs_delayed_ref_root *delayed_refs;
 743         struct btrfs_path *path;
 744         struct btrfs_extent_item *ei;
 745         struct extent_buffer *leaf;
 746         struct btrfs_key key;
 747         u32 item_size;
 748         u64 num_refs;
 749         u64 extent_flags;
 750         int ret;
 751
 752         path = btrfs_alloc_path();
 753         if (!path)
 754                 return -ENOMEM;
 755
 756         key.objectid = bytenr;
 757         key.type = BTRFS_EXTENT_ITEM_KEY;
 758         key.offset = num_bytes;
 759         if (!trans) {
 760                 path->skip_locking = 1;
 761                 path->search_commit_root = 1;
 762         }
 763 again:
 764         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 765                                 &key, path, 0, 0);
 766         if (ret < 0)
 767                 goto out_free;
 768
 769         if (ret == 0) {
 770                 leaf = path->nodes[0];
 771                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 772                 if (item_size >= sizeof(*ei)) {
 773                         ei = btrfs_item_ptr(leaf, path->slots[0],
 774                                             struct btrfs_extent_item);
 775                         num_refs = btrfs_extent_refs(leaf, ei);
 776                         extent_flags = btrfs_extent_flags(leaf, ei);
 777                 } else {
 778 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 779                         struct btrfs_extent_item_v0 *ei0;
 780                         BUG_ON(item_size != sizeof(*ei0));
 781                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 782                                              struct btrfs_extent_item_v0);
 783                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 784                         /* FIXME: this isn't correct for data */
 785                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 786 #else
 787                         BUG();
 788 #endif
 789                 }
 790                 BUG_ON(num_refs == 0);
 791         } else {
 792                 num_refs = 0;
 793                 extent_flags = 0;
 794                 ret = 0;
 795         }
 796
 797         if (!trans)
 798                 goto out;
 799
 800         delayed_refs = &trans->transaction->delayed_refs;
 801         spin_lock(&delayed_refs->lock);
 802         head = btrfs_find_delayed_ref_head(trans, bytenr);
 803         if (head) {
 804                 if (!mutex_trylock(&head->mutex)) {
 805                         atomic_inc(&head->node.refs);
 806                         spin_unlock(&delayed_refs->lock);
 807
 808                         btrfs_release_path(path);
 809
 810                         /*
 811                          * Mutex was contended, block until it's released and try
 812                          * again
 813                          */
 814                         mutex_lock(&head->mutex);
 815                         mutex_unlock(&head->mutex);
 816                         btrfs_put_delayed_ref(&head->node);
 817                         goto again;
 818                 }
 819                 if (head->extent_op && head->extent_op->update_flags)
 820                         extent_flags |= head->extent_op->flags_to_set;
 821                 else
 822                         BUG_ON(num_refs == 0);
 823
 824                 num_refs += head->node.ref_mod;
 825                 mutex_unlock(&head->mutex);
 826         }
 827         spin_unlock(&delayed_refs->lock);
 828 out:
 829         WARN_ON(num_refs == 0);
 830         if (refs)
 831                 *refs = num_refs;
 832         if (flags)
 833                 *flags = extent_flags;
 834 out_free:
 835         btrfs_free_path(path);
 836         return ret;
 837 }
 838
 839 /*
 840  * Back reference rules.  Back refs have three main goals:
 841  *
 842  * 1) differentiate between all holders of references to an extent so that
 843  *    when a reference is dropped we can make sure it was a valid reference
 844  *    before freeing the extent.
 845  *
 846  * 2) Provide enough information to quickly find the holders of an extent
 847  *    if we notice a given block is corrupted or bad.
 848  *
 849  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 850  *    maintenance.  This is actually the same as #2, but with a slightly
 851  *    different use case.
 852  *
 853  * There are two kinds of back refs. The implicit back refs is optimized
 854  * for pointers in non-shared tree blocks. For a given pointer in a block,
 855  * back refs of this kind provide information about the block's owner tree
 856  * and the pointer's key. These information allow us to find the block by
 857  * b-tree searching. The full back refs is for pointers in tree blocks not
 858  * referenced by their owner trees. The location of tree block is recorded
 859  * in the back refs. Actually the full back refs is generic, and can be
 860  * used in all cases the implicit back refs is used. The major shortcoming
 861  * of the full back refs is its overhead. Every time a tree block gets
 862  * COWed, we have to update back refs entry for all pointers in it.
 863  *
 864  * For a newly allocated tree block, we use implicit back refs for
 865  * pointers in it. This means most tree related operations only involve
 866  * implicit back refs. For a tree block created in old transaction, the
 867  * only way to drop a reference to it is COW it. So we can detect the
 868  * event that tree block loses its owner tree's reference and do the
 869  * back refs conversion.
 870  *
 871  * When a tree block is COW'd through a tree, there are four cases:
 872  *
 873  * The reference count of the block is one and the tree is the block's
 874  * owner tree. Nothing to do in this case.
 875  *
 876  * The reference count of the block is one and the tree is not the
 877  * block's owner tree. In this case, full back refs is used for pointers
 878  * in the block. Remove these full back refs, add implicit back refs for
 879  * every pointers in the new block.
 880  *
 881  * The reference count of the block is greater than one and the tree is
 882  * the block's owner tree. In this case, implicit back refs is used for
 883  * pointers in the block. Add full back refs for every pointers in the
 884  * block, increase lower level extents' reference counts. The original
 885  * implicit back refs are entailed to the new block.
 886  *
 887  * The reference count of the block is greater than one and the tree is
 888  * not the block's owner tree. Add implicit back refs for every pointer in
 889  * the new block, increase lower level extents' reference count.
 890  *
 891  * Back Reference Key composing:
 892  *
 893  * The key objectid corresponds to the first byte in the extent,
 894  * The key type is used to differentiate between types of back refs.
 895  * There are different meanings of the key offset for different types
 896  * of back refs.
 897  *
 898  * File extents can be referenced by:
 899  *
 900  * - multiple snapshots, subvolumes, or different generations in one subvol
 901  * - different files inside a single subvolume
 902  * - different offsets inside a file (bookend extents in file.c)
 903  *
 904  * The extent ref structure for the implicit back refs has fields for:
 905  *
 906  * - Objectid of the subvolume root
 907  * - objectid of the file holding the reference
 908  * - original offset in the file
 909  * - how many bookend extents
 910  *
 911  * The key offset for the implicit back refs is hash of the first
 912  * three fields.
 913  *
 914  * The extent ref structure for the full back refs has field for:
 915  *
 916  * - number of pointers in the tree leaf
 917  *
 918  * The key offset for the implicit back refs is the first byte of
 919  * the tree leaf
 920  *
 921  * When a file extent is allocated, The implicit back refs is used.
 922  * the fields are filled in:
 923  *
 924  *     (root_key.objectid, inode objectid, offset in file, 1)
 925  *
 926  * When a file extent is removed file truncation, we find the
 927  * corresponding implicit back refs and check the following fields:
 928  *
 929  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 930  *
 931  * Btree extents can be referenced by:
 932  *
 933  * - Different subvolumes
 934  *
 935  * Both the implicit back refs and the full back refs for tree blocks
 936  * only consist of key. The key offset for the implicit back refs is
 937  * objectid of block's owner tree. The key offset for the full back refs
 938  * is the first byte of parent block.
 939  *
 940  * When implicit back refs is used, information about the lowest key and
 941  * level of the tree block are required. These information are stored in
 942  * tree block info structure.
 943  */
 944
 945 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 946 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 947                                   struct btrfs_root *root,
 948                                   struct btrfs_path *path,
 949                                   u64 owner, u32 extra_size)
 950 {
 951         struct btrfs_extent_item *item;
 952         struct btrfs_extent_item_v0 *ei0;
 953         struct btrfs_extent_ref_v0 *ref0;
 954         struct btrfs_tree_block_info *bi;
 955         struct extent_buffer *leaf;
 956         struct btrfs_key key;
 957         struct btrfs_key found_key;
 958         u32 new_size = sizeof(*item);
 959         u64 refs;
 960         int ret;
 961
 962         leaf = path->nodes[0];
 963         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 964
 965         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 966         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 967                              struct btrfs_extent_item_v0);
 968         refs = btrfs_extent_refs_v0(leaf, ei0);
 969
 970         if (owner == (u64)-1) {
 971                 while (1) {
 972                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 973                                 ret = btrfs_next_leaf(root, path);
 974                                 if (ret < 0)
 975                                         return ret;
 976                                 BUG_ON(ret > 0); /* Corruption */
 977                                 leaf = path->nodes[0];
 978                         }
 979                         btrfs_item_key_to_cpu(leaf, &found_key,
 980                                               path->slots[0]);
 981                         BUG_ON(key.objectid != found_key.objectid);
 982                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 983                                 path->slots[0]++;
 984                                 continue;
 985                         }
 986                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 987                                               struct btrfs_extent_ref_v0);
 988                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 989                         break;
 990                 }
 991         }
 992         btrfs_release_path(path);
 993
 994         if (owner < BTRFS_FIRST_FREE_OBJECTID)
 995                 new_size += sizeof(*bi);
 996
 997         new_size -= sizeof(*ei0);
 998         ret = btrfs_search_slot(trans, root, &key, path,
 999                                 new_size + extra_size, 1);
1000         if (ret < 0)
1001                 return ret;
1002         BUG_ON(ret); /* Corruption */
1003
1004         btrfs_extend_item(trans, root, path, new_size);
1005
1006         leaf = path->nodes[0];
1007         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1008         btrfs_set_extent_refs(leaf, item, refs);
1009         /* FIXME: get real generation */
1010         btrfs_set_extent_generation(leaf, item, 0);
1011         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1012                 btrfs_set_extent_flags(leaf, item,
1013                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1014                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1015                 bi = (struct btrfs_tree_block_info *)(item + 1);
1016                 /* FIXME: get first key of the block */
1017                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1018                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1019         } else {
1020                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1021         }
1022         btrfs_mark_buffer_dirty(leaf);
1023         return 0;
1024 }
1025 #endif
1026
1027 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1028 {
1029         u32 high_crc = ~(u32)0;
1030         u32 low_crc = ~(u32)0;
1031         __le64 lenum;
1032
1033         lenum = cpu_to_le64(root_objectid);
1034         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1035         lenum = cpu_to_le64(owner);
1036         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1037         lenum = cpu_to_le64(offset);
1038         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1039
1040         return ((u64)high_crc << 31) ^ (u64)low_crc;
1041 }
1042
1043 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1044                                      struct btrfs_extent_data_ref *ref)
1045 {
1046         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1047                                     btrfs_extent_data_ref_objectid(leaf, ref),
1048                                     btrfs_extent_data_ref_offset(leaf, ref));
1049 }
1050
1051 static int match_extent_data_ref(struct extent_buffer *leaf,
1052                                  struct btrfs_extent_data_ref *ref,
1053                                  u64 root_objectid, u64 owner, u64 offset)
1054 {
1055         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1056             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1057             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1058                 return 0;
1059         return 1;
1060 }
1061
1062 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1063                                            struct btrfs_root *root,
1064                                            struct btrfs_path *path,
1065                                            u64 bytenr, u64 parent,
1066                                            u64 root_objectid,
1067                                            u64 owner, u64 offset)
1068 {
1069         struct btrfs_key key;
1070         struct btrfs_extent_data_ref *ref;
1071         struct extent_buffer *leaf;
1072         u32 nritems;
1073         int ret;
1074         int recow;
1075         int err = -ENOENT;
1076
1077         key.objectid = bytenr;
1078         if (parent) {
1079                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1080                 key.offset = parent;
1081         } else {
1082                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1083                 key.offset = hash_extent_data_ref(root_objectid,
1084                                                   owner, offset);
1085         }
1086 again:
1087         recow = 0;
1088         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1089         if (ret < 0) {
1090                 err = ret;
1091                 goto fail;
1092         }
1093
1094         if (parent) {
1095                 if (!ret)
1096                         return 0;
1097 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1098                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1099                 btrfs_release_path(path);
1100                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1101                 if (ret < 0) {
1102                         err = ret;
1103                         goto fail;
1104                 }
1105                 if (!ret)
1106                         return 0;
1107 #endif
1108                 goto fail;
1109         }
1110
1111         leaf = path->nodes[0];
1112         nritems = btrfs_header_nritems(leaf);
1113         while (1) {
1114                 if (path->slots[0] >= nritems) {
1115                         ret = btrfs_next_leaf(root, path);
1116                         if (ret < 0)
1117                                 err = ret;
1118                         if (ret)
1119                                 goto fail;
1120
1121                         leaf = path->nodes[0];
1122                         nritems = btrfs_header_nritems(leaf);
1123                         recow = 1;
1124                 }
1125
1126                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1127                 if (key.objectid != bytenr ||
1128                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1129                         goto fail;
1130
1131                 ref = btrfs_item_ptr(leaf, path->slots[0],
1132                                      struct btrfs_extent_data_ref);
1133
1134                 if (match_extent_data_ref(leaf, ref, root_objectid,
1135                                           owner, offset)) {
1136                         if (recow) {
1137                                 btrfs_release_path(path);
1138                                 goto again;
1139                         }
1140                         err = 0;
1141                         break;
1142                 }
1143                 path->slots[0]++;
1144         }
1145 fail:
1146         return err;
1147 }
1148
1149 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1150                                            struct btrfs_root *root,
1151                                            struct btrfs_path *path,
1152                                            u64 bytenr, u64 parent,
1153                                            u64 root_objectid, u64 owner,
1154                                            u64 offset, int refs_to_add)
1155 {
1156         struct btrfs_key key;
1157         struct extent_buffer *leaf;
1158         u32 size;
1159         u32 num_refs;
1160         int ret;
1161
1162         key.objectid = bytenr;
1163         if (parent) {
1164                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1165                 key.offset = parent;
1166                 size = sizeof(struct btrfs_shared_data_ref);
1167         } else {
1168                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1169                 key.offset = hash_extent_data_ref(root_objectid,
1170                                                   owner, offset);
1171                 size = sizeof(struct btrfs_extent_data_ref);
1172         }
1173
1174         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1175         if (ret && ret != -EEXIST)
1176                 goto fail;
1177
1178         leaf = path->nodes[0];
1179         if (parent) {
1180                 struct btrfs_shared_data_ref *ref;
1181                 ref = btrfs_item_ptr(leaf, path->slots[0],
1182                                      struct btrfs_shared_data_ref);
1183                 if (ret == 0) {
1184                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1185                 } else {
1186                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1187                         num_refs += refs_to_add;
1188                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1189                 }
1190         } else {
1191                 struct btrfs_extent_data_ref *ref;
1192                 while (ret == -EEXIST) {
1193                         ref = btrfs_item_ptr(leaf, path->slots[0],
1194                                              struct btrfs_extent_data_ref);
1195                         if (match_extent_data_ref(leaf, ref, root_objectid,
1196                                                   owner, offset))
1197                                 break;
1198                         btrfs_release_path(path);
1199                         key.offset++;
1200                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1201                                                       size);
1202                         if (ret && ret != -EEXIST)
1203                                 goto fail;
1204
1205                         leaf = path->nodes[0];
1206                 }
1207                 ref = btrfs_item_ptr(leaf, path->slots[0],
1208                                      struct btrfs_extent_data_ref);
1209                 if (ret == 0) {
1210                         btrfs_set_extent_data_ref_root(leaf, ref,
1211                                                        root_objectid);
1212                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1213                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1214                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1215                 } else {
1216                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1217                         num_refs += refs_to_add;
1218                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1219                 }
1220         }
1221         btrfs_mark_buffer_dirty(leaf);
1222         ret = 0;
1223 fail:
1224         btrfs_release_path(path);
1225         return ret;
1226 }
1227
1228 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1229                                            struct btrfs_root *root,
1230                                            struct btrfs_path *path,
1231                                            int refs_to_drop)
1232 {
1233         struct btrfs_key key;
1234         struct btrfs_extent_data_ref *ref1 = NULL;
1235         struct btrfs_shared_data_ref *ref2 = NULL;
1236         struct extent_buffer *leaf;
1237         u32 num_refs = 0;
1238         int ret = 0;
1239
1240         leaf = path->nodes[0];
1241         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1242
1243         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1244                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1245                                       struct btrfs_extent_data_ref);
1246                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1247         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1248                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1249                                       struct btrfs_shared_data_ref);
1250                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1251 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1252         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1253                 struct btrfs_extent_ref_v0 *ref0;
1254                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1255                                       struct btrfs_extent_ref_v0);
1256                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1257 #endif
1258         } else {
1259                 BUG();
1260         }
1261
1262         BUG_ON(num_refs < refs_to_drop);
1263         num_refs -= refs_to_drop;
1264
1265         if (num_refs == 0) {
1266                 ret = btrfs_del_item(trans, root, path);
1267         } else {
1268                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1269                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1270                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1271                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1272 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1273                 else {
1274                         struct btrfs_extent_ref_v0 *ref0;
1275                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1276                                         struct btrfs_extent_ref_v0);
1277                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1278                 }
1279 #endif
1280                 btrfs_mark_buffer_dirty(leaf);
1281         }
1282         return ret;
1283 }
1284
1285 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1286                                           struct btrfs_path *path,
1287                                           struct btrfs_extent_inline_ref *iref)
1288 {
1289         struct btrfs_key key;
1290         struct extent_buffer *leaf;
1291         struct btrfs_extent_data_ref *ref1;
1292         struct btrfs_shared_data_ref *ref2;
1293         u32 num_refs = 0;
1294
1295         leaf = path->nodes[0];
1296         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1297         if (iref) {
1298                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1299                     BTRFS_EXTENT_DATA_REF_KEY) {
1300                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1301                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1302                 } else {
1303                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1304                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1305                 }
1306         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1307                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1308                                       struct btrfs_extent_data_ref);
1309                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1310         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1311                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1312                                       struct btrfs_shared_data_ref);
1313                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1314 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1315         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1316                 struct btrfs_extent_ref_v0 *ref0;
1317                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1318                                       struct btrfs_extent_ref_v0);
1319                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1320 #endif
1321         } else {
1322                 WARN_ON(1);
1323         }
1324         return num_refs;
1325 }
1326
1327 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1328                                           struct btrfs_root *root,
1329                                           struct btrfs_path *path,
1330                                           u64 bytenr, u64 parent,
1331                                           u64 root_objectid)
1332 {
1333         struct btrfs_key key;
1334         int ret;
1335
1336         key.objectid = bytenr;
1337         if (parent) {
1338                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1339                 key.offset = parent;
1340         } else {
1341                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1342                 key.offset = root_objectid;
1343         }
1344
1345         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1346         if (ret > 0)
1347                 ret = -ENOENT;
1348 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1349         if (ret == -ENOENT && parent) {
1350                 btrfs_release_path(path);
1351                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1352                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1353                 if (ret > 0)
1354                         ret = -ENOENT;
1355         }
1356 #endif
1357         return ret;
1358 }
1359
1360 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1361                                           struct btrfs_root *root,
1362                                           struct btrfs_path *path,
1363                                           u64 bytenr, u64 parent,
1364                                           u64 root_objectid)
1365 {
1366         struct btrfs_key key;
1367         int ret;
1368
1369         key.objectid = bytenr;
1370         if (parent) {
1371                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1372                 key.offset = parent;
1373         } else {
1374                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1375                 key.offset = root_objectid;
1376         }
1377
1378         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1379         btrfs_release_path(path);
1380         return ret;
1381 }
1382
1383 static inline int extent_ref_type(u64 parent, u64 owner)
1384 {
1385         int type;
1386         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1387                 if (parent > 0)
1388                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1389                 else
1390                         type = BTRFS_TREE_BLOCK_REF_KEY;
1391         } else {
1392                 if (parent > 0)
1393                         type = BTRFS_SHARED_DATA_REF_KEY;
1394                 else
1395                         type = BTRFS_EXTENT_DATA_REF_KEY;
1396         }
1397         return type;
1398 }
1399
1400 static int find_next_key(struct btrfs_path *path, int level,
1401                          struct btrfs_key *key)
1402
1403 {
1404         for (; level < BTRFS_MAX_LEVEL; level++) {
1405                 if (!path->nodes[level])
1406                         break;
1407                 if (path->slots[level] + 1 >=
1408                     btrfs_header_nritems(path->nodes[level]))
1409                         continue;
1410                 if (level == 0)
1411                         btrfs_item_key_to_cpu(path->nodes[level], key,
1412                                               path->slots[level] + 1);
1413                 else
1414                         btrfs_node_key_to_cpu(path->nodes[level], key,
1415                                               path->slots[level] + 1);
1416                 return 0;
1417         }
1418         return 1;
1419 }
1420
1421 /*
1422  * look for inline back ref. if back ref is found, *ref_ret is set
1423  * to the address of inline back ref, and 0 is returned.
1424  *
1425  * if back ref isn't found, *ref_ret is set to the address where it
1426  * should be inserted, and -ENOENT is returned.
1427  *
1428  * if insert is true and there are too many inline back refs, the path
1429  * points to the extent item, and -EAGAIN is returned.
1430  *
1431  * NOTE: inline back refs are ordered in the same way that back ref
1432  *       items in the tree are ordered.
1433  */
1434 static noinline_for_stack
1435 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1436                                  struct btrfs_root *root,
1437                                  struct btrfs_path *path,
1438                                  struct btrfs_extent_inline_ref **ref_ret,
1439                                  u64 bytenr, u64 num_bytes,
1440                                  u64 parent, u64 root_objectid,
1441                                  u64 owner, u64 offset, int insert)
1442 {
1443         struct btrfs_key key;
1444         struct extent_buffer *leaf;
1445         struct btrfs_extent_item *ei;
1446         struct btrfs_extent_inline_ref *iref;
1447         u64 flags;
1448         u64 item_size;
1449         unsigned long ptr;
1450         unsigned long end;
1451         int extra_size;
1452         int type;
1453         int want;
1454         int ret;
1455         int err = 0;
1456
1457         key.objectid = bytenr;
1458         key.type = BTRFS_EXTENT_ITEM_KEY;
1459         key.offset = num_bytes;
1460
1461         want = extent_ref_type(parent, owner);
1462         if (insert) {
1463                 extra_size = btrfs_extent_inline_ref_size(want);
1464                 path->keep_locks = 1;
1465         } else
1466                 extra_size = -1;
1467         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1468         if (ret < 0) {
1469                 err = ret;
1470                 goto out;
1471         }
1472         if (ret && !insert) {
1473                 err = -ENOENT;
1474                 goto out;
1475         } else if (ret) {
1476                 err = -EIO;
1477                 WARN_ON(1);
1478                 goto out;
1479         }
1480
1481         leaf = path->nodes[0];
1482         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1483 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1484         if (item_size < sizeof(*ei)) {
1485                 if (!insert) {
1486                         err = -ENOENT;
1487                         goto out;
1488                 }
1489                 ret = convert_extent_item_v0(trans, root, path, owner,
1490                                              extra_size);
1491                 if (ret < 0) {
1492                         err = ret;
1493                         goto out;
1494                 }
1495                 leaf = path->nodes[0];
1496                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1497         }
1498 #endif
1499         BUG_ON(item_size < sizeof(*ei));
1500
1501         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1502         flags = btrfs_extent_flags(leaf, ei);
1503
1504         ptr = (unsigned long)(ei + 1);
1505         end = (unsigned long)ei + item_size;
1506
1507         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1508                 ptr += sizeof(struct btrfs_tree_block_info);
1509                 BUG_ON(ptr > end);
1510         } else {
1511                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1512         }
1513
1514         err = -ENOENT;
1515         while (1) {
1516                 if (ptr >= end) {
1517                         WARN_ON(ptr > end);
1518                         break;
1519                 }
1520                 iref = (struct btrfs_extent_inline_ref *)ptr;
1521                 type = btrfs_extent_inline_ref_type(leaf, iref);
1522                 if (want < type)
1523                         break;
1524                 if (want > type) {
1525                         ptr += btrfs_extent_inline_ref_size(type);
1526                         continue;
1527                 }
1528
1529                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1530                         struct btrfs_extent_data_ref *dref;
1531                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1532                         if (match_extent_data_ref(leaf, dref, root_objectid,
1533                                                   owner, offset)) {
1534                                 err = 0;
1535                                 break;
1536                         }
1537                         if (hash_extent_data_ref_item(leaf, dref) <
1538                             hash_extent_data_ref(root_objectid, owner, offset))
1539                                 break;
1540                 } else {
1541                         u64 ref_offset;
1542                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1543                         if (parent > 0) {
1544                                 if (parent == ref_offset) {
1545                                         err = 0;
1546                                         break;
1547                                 }
1548                                 if (ref_offset < parent)
1549                                         break;
1550                         } else {
1551                                 if (root_objectid == ref_offset) {
1552                                         err = 0;
1553                                         break;
1554                                 }
1555                                 if (ref_offset < root_objectid)
1556                                         break;
1557                         }
1558                 }
1559                 ptr += btrfs_extent_inline_ref_size(type);
1560         }
1561         if (err == -ENOENT && insert) {
1562                 if (item_size + extra_size >=
1563                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1564                         err = -EAGAIN;
1565                         goto out;
1566                 }
1567                 /*
1568                  * To add new inline back ref, we have to make sure
1569                  * there is no corresponding back ref item.
1570                  * For simplicity, we just do not add new inline back
1571                  * ref if there is any kind of item for this block
1572                  */
1573                 if (find_next_key(path, 0, &key) == 0 &&
1574                     key.objectid == bytenr &&
1575                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1576                         err = -EAGAIN;
1577                         goto out;
1578                 }
1579         }
1580         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1581 out:
1582         if (insert) {
1583                 path->keep_locks = 0;
1584                 btrfs_unlock_up_safe(path, 1);
1585         }
1586         return err;
1587 }
1588
1589 /*
1590  * helper to add new inline back ref
1591  */
1592 static noinline_for_stack
1593 void setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1594                                  struct btrfs_root *root,
1595                                  struct btrfs_path *path,
1596                                  struct btrfs_extent_inline_ref *iref,
1597                                  u64 parent, u64 root_objectid,
1598                                  u64 owner, u64 offset, int refs_to_add,
1599                                  struct btrfs_delayed_extent_op *extent_op)
1600 {
1601         struct extent_buffer *leaf;
1602         struct btrfs_extent_item *ei;
1603         unsigned long ptr;
1604         unsigned long end;
1605         unsigned long item_offset;
1606         u64 refs;
1607         int size;
1608         int type;
1609
1610         leaf = path->nodes[0];
1611         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1612         item_offset = (unsigned long)iref - (unsigned long)ei;
1613
1614         type = extent_ref_type(parent, owner);
1615         size = btrfs_extent_inline_ref_size(type);
1616
1617         btrfs_extend_item(trans, root, path, size);
1618
1619         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1620         refs = btrfs_extent_refs(leaf, ei);
1621         refs += refs_to_add;
1622         btrfs_set_extent_refs(leaf, ei, refs);
1623         if (extent_op)
1624                 __run_delayed_extent_op(extent_op, leaf, ei);
1625
1626         ptr = (unsigned long)ei + item_offset;
1627         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1628         if (ptr < end - size)
1629                 memmove_extent_buffer(leaf, ptr + size, ptr,
1630                                       end - size - ptr);
1631
1632         iref = (struct btrfs_extent_inline_ref *)ptr;
1633         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1634         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1635                 struct btrfs_extent_data_ref *dref;
1636                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1637                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1638                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1639                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1640                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1641         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1642                 struct btrfs_shared_data_ref *sref;
1643                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1644                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1645                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1646         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1647                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1648         } else {
1649                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1650         }
1651         btrfs_mark_buffer_dirty(leaf);
1652 }
1653
1654 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1655                                  struct btrfs_root *root,
1656                                  struct btrfs_path *path,
1657                                  struct btrfs_extent_inline_ref **ref_ret,
1658                                  u64 bytenr, u64 num_bytes, u64 parent,
1659                                  u64 root_objectid, u64 owner, u64 offset)
1660 {
1661         int ret;
1662
1663         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1664                                            bytenr, num_bytes, parent,
1665                                            root_objectid, owner, offset, 0);
1666         if (ret != -ENOENT)
1667                 return ret;
1668
1669         btrfs_release_path(path);
1670         *ref_ret = NULL;
1671
1672         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1673                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1674                                             root_objectid);
1675         } else {
1676                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1677                                              root_objectid, owner, offset);
1678         }
1679         return ret;
1680 }
1681
1682 /*
1683  * helper to update/remove inline back ref
1684  */
1685 static noinline_for_stack
1686 void update_inline_extent_backref(struct btrfs_trans_handle *trans,
1687                                   struct btrfs_root *root,
1688                                   struct btrfs_path *path,
1689                                   struct btrfs_extent_inline_ref *iref,
1690                                   int refs_to_mod,
1691                                   struct btrfs_delayed_extent_op *extent_op)
1692 {
1693         struct extent_buffer *leaf;
1694         struct btrfs_extent_item *ei;
1695         struct btrfs_extent_data_ref *dref = NULL;
1696         struct btrfs_shared_data_ref *sref = NULL;
1697         unsigned long ptr;
1698         unsigned long end;
1699         u32 item_size;
1700         int size;
1701         int type;
1702         u64 refs;
1703
1704         leaf = path->nodes[0];
1705         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1706         refs = btrfs_extent_refs(leaf, ei);
1707         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1708         refs += refs_to_mod;
1709         btrfs_set_extent_refs(leaf, ei, refs);
1710         if (extent_op)
1711                 __run_delayed_extent_op(extent_op, leaf, ei);
1712
1713         type = btrfs_extent_inline_ref_type(leaf, iref);
1714
1715         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1716                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1717                 refs = btrfs_extent_data_ref_count(leaf, dref);
1718         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1719                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1720                 refs = btrfs_shared_data_ref_count(leaf, sref);
1721         } else {
1722                 refs = 1;
1723                 BUG_ON(refs_to_mod != -1);
1724         }
1725
1726         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1727         refs += refs_to_mod;
1728
1729         if (refs > 0) {
1730                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1731                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1732                 else
1733                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1734         } else {
1735                 size =  btrfs_extent_inline_ref_size(type);
1736                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1737                 ptr = (unsigned long)iref;
1738                 end = (unsigned long)ei + item_size;
1739                 if (ptr + size < end)
1740                         memmove_extent_buffer(leaf, ptr, ptr + size,
1741                                               end - ptr - size);
1742                 item_size -= size;
1743                 btrfs_truncate_item(trans, root, path, item_size, 1);
1744         }
1745         btrfs_mark_buffer_dirty(leaf);
1746 }
1747
1748 static noinline_for_stack
1749 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1750                                  struct btrfs_root *root,
1751                                  struct btrfs_path *path,
1752                                  u64 bytenr, u64 num_bytes, u64 parent,
1753                                  u64 root_objectid, u64 owner,
1754                                  u64 offset, int refs_to_add,
1755                                  struct btrfs_delayed_extent_op *extent_op)
1756 {
1757         struct btrfs_extent_inline_ref *iref;
1758         int ret;
1759
1760         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1761                                            bytenr, num_bytes, parent,
1762                                            root_objectid, owner, offset, 1);
1763         if (ret == 0) {
1764                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1765                 update_inline_extent_backref(trans, root, path, iref,
1766                                              refs_to_add, extent_op);
1767         } else if (ret == -ENOENT) {
1768                 setup_inline_extent_backref(trans, root, path, iref, parent,
1769                                             root_objectid, owner, offset,
1770                                             refs_to_add, extent_op);
1771                 ret = 0;
1772         }
1773         return ret;
1774 }
1775
1776 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1777                                  struct btrfs_root *root,
1778                                  struct btrfs_path *path,
1779                                  u64 bytenr, u64 parent, u64 root_objectid,
1780                                  u64 owner, u64 offset, int refs_to_add)
1781 {
1782         int ret;
1783         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1784                 BUG_ON(refs_to_add != 1);
1785                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1786                                             parent, root_objectid);
1787         } else {
1788                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1789                                              parent, root_objectid,
1790                                              owner, offset, refs_to_add);
1791         }
1792         return ret;
1793 }
1794
1795 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1796                                  struct btrfs_root *root,
1797                                  struct btrfs_path *path,
1798                                  struct btrfs_extent_inline_ref *iref,
1799                                  int refs_to_drop, int is_data)
1800 {
1801         int ret = 0;
1802
1803         BUG_ON(!is_data && refs_to_drop != 1);
1804         if (iref) {
1805                 update_inline_extent_backref(trans, root, path, iref,
1806                                              -refs_to_drop, NULL);
1807         } else if (is_data) {
1808                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1809         } else {
1810                 ret = btrfs_del_item(trans, root, path);
1811         }
1812         return ret;
1813 }
1814
1815 static int btrfs_issue_discard(struct block_device *bdev,
1816                                 u64 start, u64 len)
1817 {
1818         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1819 }
1820
1821 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1822                                 u64 num_bytes, u64 *actual_bytes)
1823 {
1824         int ret;
1825         u64 discarded_bytes = 0;
1826         struct btrfs_bio *bbio = NULL;
1827
1828
1829         /* Tell the block device(s) that the sectors can be discarded */
1830         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1831                               bytenr, &num_bytes, &bbio, 0);
1832         /* Error condition is -ENOMEM */
1833         if (!ret) {
1834                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1835                 int i;
1836
1837
1838                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1839                         if (!stripe->dev->can_discard)
1840                                 continue;
1841
1842                         ret = btrfs_issue_discard(stripe->dev->bdev,
1843                                                   stripe->physical,
1844                                                   stripe->length);
1845                         if (!ret)
1846                                 discarded_bytes += stripe->length;
1847                         else if (ret != -EOPNOTSUPP)
1848                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1849
1850                         /*
1851                          * Just in case we get back EOPNOTSUPP for some reason,
1852                          * just ignore the return value so we don't screw up
1853                          * people calling discard_extent.
1854                          */
1855                         ret = 0;
1856                 }
1857                 kfree(bbio);
1858         }
1859
1860         if (actual_bytes)
1861                 *actual_bytes = discarded_bytes;
1862
1863
1864         if (ret == -EOPNOTSUPP)
1865                 ret = 0;
1866         return ret;
1867 }
1868
1869 /* Can return -ENOMEM */
1870 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1871                          struct btrfs_root *root,
1872                          u64 bytenr, u64 num_bytes, u64 parent,
1873                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1874 {
1875         int ret;
1876         struct btrfs_fs_info *fs_info = root->fs_info;
1877
1878         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1879                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1880
1881         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1882                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1883                                         num_bytes,
1884                                         parent, root_objectid, (int)owner,
1885                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1886         } else {
1887                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1888                                         num_bytes,
1889                                         parent, root_objectid, owner, offset,
1890                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1891         }
1892         return ret;
1893 }
1894
1895 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1896                                   struct btrfs_root *root,
1897                                   u64 bytenr, u64 num_bytes,
1898                                   u64 parent, u64 root_objectid,
1899                                   u64 owner, u64 offset, int refs_to_add,
1900                                   struct btrfs_delayed_extent_op *extent_op)
1901 {
1902         struct btrfs_path *path;
1903         struct extent_buffer *leaf;
1904         struct btrfs_extent_item *item;
1905         u64 refs;
1906         int ret;
1907         int err = 0;
1908
1909         path = btrfs_alloc_path();
1910         if (!path)
1911                 return -ENOMEM;
1912
1913         path->reada = 1;
1914         path->leave_spinning = 1;
1915         /* this will setup the path even if it fails to insert the back ref */
1916         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1917                                            path, bytenr, num_bytes, parent,
1918                                            root_objectid, owner, offset,
1919                                            refs_to_add, extent_op);
1920         if (ret == 0)
1921                 goto out;
1922
1923         if (ret != -EAGAIN) {
1924                 err = ret;
1925                 goto out;
1926         }
1927
1928         leaf = path->nodes[0];
1929         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1930         refs = btrfs_extent_refs(leaf, item);
1931         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1932         if (extent_op)
1933                 __run_delayed_extent_op(extent_op, leaf, item);
1934
1935         btrfs_mark_buffer_dirty(leaf);
1936         btrfs_release_path(path);
1937
1938         path->reada = 1;
1939         path->leave_spinning = 1;
1940
1941         /* now insert the actual backref */
1942         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1943                                     path, bytenr, parent, root_objectid,
1944                                     owner, offset, refs_to_add);
1945         if (ret)
1946                 btrfs_abort_transaction(trans, root, ret);
1947 out:
1948         btrfs_free_path(path);
1949         return err;
1950 }
1951
1952 static int run_delayed_data_ref(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                                 int insert_reserved)
1957 {
1958         int ret = 0;
1959         struct btrfs_delayed_data_ref *ref;
1960         struct btrfs_key ins;
1961         u64 parent = 0;
1962         u64 ref_root = 0;
1963         u64 flags = 0;
1964
1965         ins.objectid = node->bytenr;
1966         ins.offset = node->num_bytes;
1967         ins.type = BTRFS_EXTENT_ITEM_KEY;
1968
1969         ref = btrfs_delayed_node_to_data_ref(node);
1970         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1971                 parent = ref->parent;
1972         else
1973                 ref_root = ref->root;
1974
1975         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1976                 if (extent_op) {
1977                         BUG_ON(extent_op->update_key);
1978                         flags |= extent_op->flags_to_set;
1979                 }
1980                 ret = alloc_reserved_file_extent(trans, root,
1981                                                  parent, ref_root, flags,
1982                                                  ref->objectid, ref->offset,
1983                                                  &ins, node->ref_mod);
1984         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1985                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1986                                              node->num_bytes, parent,
1987                                              ref_root, ref->objectid,
1988                                              ref->offset, node->ref_mod,
1989                                              extent_op);
1990         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1991                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1992                                           node->num_bytes, parent,
1993                                           ref_root, ref->objectid,
1994                                           ref->offset, node->ref_mod,
1995                                           extent_op);
1996         } else {
1997                 BUG();
1998         }
1999         return ret;
2000 }
2001
2002 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2003                                     struct extent_buffer *leaf,
2004                                     struct btrfs_extent_item *ei)
2005 {
2006         u64 flags = btrfs_extent_flags(leaf, ei);
2007         if (extent_op->update_flags) {
2008                 flags |= extent_op->flags_to_set;
2009                 btrfs_set_extent_flags(leaf, ei, flags);
2010         }
2011
2012         if (extent_op->update_key) {
2013                 struct btrfs_tree_block_info *bi;
2014                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2015                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2016                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2017         }
2018 }
2019
2020 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2021                                  struct btrfs_root *root,
2022                                  struct btrfs_delayed_ref_node *node,
2023                                  struct btrfs_delayed_extent_op *extent_op)
2024 {
2025         struct btrfs_key key;
2026         struct btrfs_path *path;
2027         struct btrfs_extent_item *ei;
2028         struct extent_buffer *leaf;
2029         u32 item_size;
2030         int ret;
2031         int err = 0;
2032
2033         if (trans->aborted)
2034                 return 0;
2035
2036         path = btrfs_alloc_path();
2037         if (!path)
2038                 return -ENOMEM;
2039
2040         key.objectid = node->bytenr;
2041         key.type = BTRFS_EXTENT_ITEM_KEY;
2042         key.offset = node->num_bytes;
2043
2044         path->reada = 1;
2045         path->leave_spinning = 1;
2046         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2047                                 path, 0, 1);
2048         if (ret < 0) {
2049                 err = ret;
2050                 goto out;
2051         }
2052         if (ret > 0) {
2053                 err = -EIO;
2054                 goto out;
2055         }
2056
2057         leaf = path->nodes[0];
2058         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2059 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2060         if (item_size < sizeof(*ei)) {
2061                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2062                                              path, (u64)-1, 0);
2063                 if (ret < 0) {
2064                         err = ret;
2065                         goto out;
2066                 }
2067                 leaf = path->nodes[0];
2068                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2069         }
2070 #endif
2071         BUG_ON(item_size < sizeof(*ei));
2072         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2073         __run_delayed_extent_op(extent_op, leaf, ei);
2074
2075         btrfs_mark_buffer_dirty(leaf);
2076 out:
2077         btrfs_free_path(path);
2078         return err;
2079 }
2080
2081 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2082                                 struct btrfs_root *root,
2083                                 struct btrfs_delayed_ref_node *node,
2084                                 struct btrfs_delayed_extent_op *extent_op,
2085                                 int insert_reserved)
2086 {
2087         int ret = 0;
2088         struct btrfs_delayed_tree_ref *ref;
2089         struct btrfs_key ins;
2090         u64 parent = 0;
2091         u64 ref_root = 0;
2092
2093         ins.objectid = node->bytenr;
2094         ins.offset = node->num_bytes;
2095         ins.type = BTRFS_EXTENT_ITEM_KEY;
2096
2097         ref = btrfs_delayed_node_to_tree_ref(node);
2098         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2099                 parent = ref->parent;
2100         else
2101                 ref_root = ref->root;
2102
2103         BUG_ON(node->ref_mod != 1);
2104         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2105                 BUG_ON(!extent_op || !extent_op->update_flags ||
2106                        !extent_op->update_key);
2107                 ret = alloc_reserved_tree_block(trans, root,
2108                                                 parent, ref_root,
2109                                                 extent_op->flags_to_set,
2110                                                 &extent_op->key,
2111                                                 ref->level, &ins);
2112         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2113                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2114                                              node->num_bytes, parent, ref_root,
2115                                              ref->level, 0, 1, extent_op);
2116         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2117                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2118                                           node->num_bytes, parent, ref_root,
2119                                           ref->level, 0, 1, extent_op);
2120         } else {
2121                 BUG();
2122         }
2123         return ret;
2124 }
2125
2126 /* helper function to actually process a single delayed ref entry */
2127 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2128                                struct btrfs_root *root,
2129                                struct btrfs_delayed_ref_node *node,
2130                                struct btrfs_delayed_extent_op *extent_op,
2131                                int insert_reserved)
2132 {
2133         int ret = 0;
2134
2135         if (trans->aborted)
2136                 return 0;
2137
2138         if (btrfs_delayed_ref_is_head(node)) {
2139                 struct btrfs_delayed_ref_head *head;
2140                 /*
2141                  * we've hit the end of the chain and we were supposed
2142                  * to insert this extent into the tree.  But, it got
2143                  * deleted before we ever needed to insert it, so all
2144                  * we have to do is clean up the accounting
2145                  */
2146                 BUG_ON(extent_op);
2147                 head = btrfs_delayed_node_to_head(node);
2148                 if (insert_reserved) {
2149                         btrfs_pin_extent(root, node->bytenr,
2150                                          node->num_bytes, 1);
2151                         if (head->is_data) {
2152                                 ret = btrfs_del_csums(trans, root,
2153                                                       node->bytenr,
2154                                                       node->num_bytes);
2155                         }
2156                 }
2157                 return ret;
2158         }
2159
2160         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2161             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2162                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2163                                            insert_reserved);
2164         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2165                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2166                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2167                                            insert_reserved);
2168         else
2169                 BUG();
2170         return ret;
2171 }
2172
2173 static noinline struct btrfs_delayed_ref_node *
2174 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2175 {
2176         struct rb_node *node;
2177         struct btrfs_delayed_ref_node *ref;
2178         int action = BTRFS_ADD_DELAYED_REF;
2179 again:
2180         /*
2181          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2182          * this prevents ref count from going down to zero when
2183          * there still are pending delayed ref.
2184          */
2185         node = rb_prev(&head->node.rb_node);
2186         while (1) {
2187                 if (!node)
2188                         break;
2189                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2190                                 rb_node);
2191                 if (ref->bytenr != head->node.bytenr)
2192                         break;
2193                 if (ref->action == action)
2194                         return ref;
2195                 node = rb_prev(node);
2196         }
2197         if (action == BTRFS_ADD_DELAYED_REF) {
2198                 action = BTRFS_DROP_DELAYED_REF;
2199                 goto again;
2200         }
2201         return NULL;
2202 }
2203
2204 /*
2205  * Returns 0 on success or if called with an already aborted transaction.
2206  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2207  */
2208 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2209                                        struct btrfs_root *root,
2210                                        struct list_head *cluster)
2211 {
2212         struct btrfs_delayed_ref_root *delayed_refs;
2213         struct btrfs_delayed_ref_node *ref;
2214         struct btrfs_delayed_ref_head *locked_ref = NULL;
2215         struct btrfs_delayed_extent_op *extent_op;
2216         struct btrfs_fs_info *fs_info = root->fs_info;
2217         int ret;
2218         int count = 0;
2219         int must_insert_reserved = 0;
2220
2221         delayed_refs = &trans->transaction->delayed_refs;
2222         while (1) {
2223                 if (!locked_ref) {
2224                         /* pick a new head ref from the cluster list */
2225                         if (list_empty(cluster))
2226                                 break;
2227
2228                         locked_ref = list_entry(cluster->next,
2229                                      struct btrfs_delayed_ref_head, cluster);
2230
2231                         /* grab the lock that says we are going to process
2232                          * all the refs for this head */
2233                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2234
2235                         /*
2236                          * we may have dropped the spin lock to get the head
2237                          * mutex lock, and that might have given someone else
2238                          * time to free the head.  If that's true, it has been
2239                          * removed from our list and we can move on.
2240                          */
2241                         if (ret == -EAGAIN) {
2242                                 locked_ref = NULL;
2243                                 count++;
2244                                 continue;
2245                         }
2246                 }
2247
2248                 /*
2249                  * We need to try and merge add/drops of the same ref since we
2250                  * can run into issues with relocate dropping the implicit ref
2251                  * and then it being added back again before the drop can
2252                  * finish.  If we merged anything we need to re-loop so we can
2253                  * get a good ref.
2254                  */
2255                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2256                                          locked_ref);
2257
2258                 /*
2259                  * locked_ref is the head node, so we have to go one
2260                  * node back for any delayed ref updates
2261                  */
2262                 ref = select_delayed_ref(locked_ref);
2263
2264                 if (ref && ref->seq &&
2265                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2266                         /*
2267                          * there are still refs with lower seq numbers in the
2268                          * process of being added. Don't run this ref yet.
2269                          */
2270                         list_del_init(&locked_ref->cluster);
2271                         btrfs_delayed_ref_unlock(locked_ref);
2272                         locked_ref = NULL;
2273                         delayed_refs->num_heads_ready++;
2274                         spin_unlock(&delayed_refs->lock);
2275                         cond_resched();
2276                         spin_lock(&delayed_refs->lock);
2277                         continue;
2278                 }
2279
2280                 /*
2281                  * record the must insert reserved flag before we
2282                  * drop the spin lock.
2283                  */
2284                 must_insert_reserved = locked_ref->must_insert_reserved;
2285                 locked_ref->must_insert_reserved = 0;
2286
2287                 extent_op = locked_ref->extent_op;
2288                 locked_ref->extent_op = NULL;
2289
2290                 if (!ref) {
2291                         /* All delayed refs have been processed, Go ahead
2292                          * and send the head node to run_one_delayed_ref,
2293                          * so that any accounting fixes can happen
2294                          */
2295                         ref = &locked_ref->node;
2296
2297                         if (extent_op && must_insert_reserved) {
2298                                 btrfs_free_delayed_extent_op(extent_op);
2299                                 extent_op = NULL;
2300                         }
2301
2302                         if (extent_op) {
2303                                 spin_unlock(&delayed_refs->lock);
2304
2305                                 ret = run_delayed_extent_op(trans, root,
2306                                                             ref, extent_op);
2307                                 btrfs_free_delayed_extent_op(extent_op);
2308
2309                                 if (ret) {
2310                                         printk(KERN_DEBUG
2311                                                "btrfs: run_delayed_extent_op "
2312                                                "returned %d\n", ret);
2313                                         spin_lock(&delayed_refs->lock);
2314                                         btrfs_delayed_ref_unlock(locked_ref);
2315                                         return ret;
2316                                 }
2317
2318                                 goto next;
2319                         }
2320                 }
2321
2322                 ref->in_tree = 0;
2323                 rb_erase(&ref->rb_node, &delayed_refs->root);
2324                 delayed_refs->num_entries--;
2325                 if (!btrfs_delayed_ref_is_head(ref)) {
2326                         /*
2327                          * when we play the delayed ref, also correct the
2328                          * ref_mod on head
2329                          */
2330                         switch (ref->action) {
2331                         case BTRFS_ADD_DELAYED_REF:
2332                         case BTRFS_ADD_DELAYED_EXTENT:
2333                                 locked_ref->node.ref_mod -= ref->ref_mod;
2334                                 break;
2335                         case BTRFS_DROP_DELAYED_REF:
2336                                 locked_ref->node.ref_mod += ref->ref_mod;
2337                                 break;
2338                         default:
2339                                 WARN_ON(1);
2340                         }
2341                 }
2342                 spin_unlock(&delayed_refs->lock);
2343
2344                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2345                                           must_insert_reserved);
2346
2347                 btrfs_free_delayed_extent_op(extent_op);
2348                 if (ret) {
2349                         btrfs_delayed_ref_unlock(locked_ref);
2350                         btrfs_put_delayed_ref(ref);
2351                         printk(KERN_DEBUG
2352                                "btrfs: run_one_delayed_ref returned %d\n", ret);
2353                         spin_lock(&delayed_refs->lock);
2354                         return ret;
2355                 }
2356
2357                 /*
2358                  * If this node is a head, that means all the refs in this head
2359                  * have been dealt with, and we will pick the next head to deal
2360                  * with, so we must unlock the head and drop it from the cluster
2361                  * list before we release it.
2362                  */
2363                 if (btrfs_delayed_ref_is_head(ref)) {
2364                         list_del_init(&locked_ref->cluster);
2365                         btrfs_delayed_ref_unlock(locked_ref);
2366                         locked_ref = NULL;
2367                 }
2368                 btrfs_put_delayed_ref(ref);
2369                 count++;
2370 next:
2371                 cond_resched();
2372                 spin_lock(&delayed_refs->lock);
2373         }
2374         return count;
2375 }
2376
2377 #ifdef SCRAMBLE_DELAYED_REFS
2378 /*
2379  * Normally delayed refs get processed in ascending bytenr order. This
2380  * correlates in most cases to the order added. To expose dependencies on this
2381  * order, we start to process the tree in the middle instead of the beginning
2382  */
2383 static u64 find_middle(struct rb_root *root)
2384 {
2385         struct rb_node *n = root->rb_node;
2386         struct btrfs_delayed_ref_node *entry;
2387         int alt = 1;
2388         u64 middle;
2389         u64 first = 0, last = 0;
2390
2391         n = rb_first(root);
2392         if (n) {
2393                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2394                 first = entry->bytenr;
2395         }
2396         n = rb_last(root);
2397         if (n) {
2398                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2399                 last = entry->bytenr;
2400         }
2401         n = root->rb_node;
2402
2403         while (n) {
2404                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2405                 WARN_ON(!entry->in_tree);
2406
2407                 middle = entry->bytenr;
2408
2409                 if (alt)
2410                         n = n->rb_left;
2411                 else
2412                         n = n->rb_right;
2413
2414                 alt = 1 - alt;
2415         }
2416         return middle;
2417 }
2418 #endif
2419
2420 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2421                                          struct btrfs_fs_info *fs_info)
2422 {
2423         struct qgroup_update *qgroup_update;
2424         int ret = 0;
2425
2426         if (list_empty(&trans->qgroup_ref_list) !=
2427             !trans->delayed_ref_elem.seq) {
2428                 /* list without seq or seq without list */
2429                 printk(KERN_ERR "btrfs: qgroup accounting update error, list is%s empty, seq is %llu\n",
2430                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2431                         trans->delayed_ref_elem.seq);
2432                 BUG();
2433         }
2434
2435         if (!trans->delayed_ref_elem.seq)
2436                 return 0;
2437
2438         while (!list_empty(&trans->qgroup_ref_list)) {
2439                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2440                                                  struct qgroup_update, list);
2441                 list_del(&qgroup_update->list);
2442                 if (!ret)
2443                         ret = btrfs_qgroup_account_ref(
2444                                         trans, fs_info, qgroup_update->node,
2445                                         qgroup_update->extent_op);
2446                 kfree(qgroup_update);
2447         }
2448
2449         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2450
2451         return ret;
2452 }
2453
2454 static int refs_newer(struct btrfs_delayed_ref_root *delayed_refs, int seq,
2455                       int count)
2456 {
2457         int val = atomic_read(&delayed_refs->ref_seq);
2458
2459         if (val < seq || val >= seq + count)
2460                 return 1;
2461         return 0;
2462 }
2463
2464 /*
2465  * this starts processing the delayed reference count updates and
2466  * extent insertions we have queued up so far.  count can be
2467  * 0, which means to process everything in the tree at the start
2468  * of the run (but not newly added entries), or it can be some target
2469  * number you'd like to process.
2470  *
2471  * Returns 0 on success or if called with an aborted transaction
2472  * Returns <0 on error and aborts the transaction
2473  */
2474 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2475                            struct btrfs_root *root, unsigned long count)
2476 {
2477         struct rb_node *node;
2478         struct btrfs_delayed_ref_root *delayed_refs;
2479         struct btrfs_delayed_ref_node *ref;
2480         struct list_head cluster;
2481         int ret;
2482         u64 delayed_start;
2483         int run_all = count == (unsigned long)-1;
2484         int run_most = 0;
2485         int loops;
2486
2487         /* We'll clean this up in btrfs_cleanup_transaction */
2488         if (trans->aborted)
2489                 return 0;
2490
2491         if (root == root->fs_info->extent_root)
2492                 root = root->fs_info->tree_root;
2493
2494         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2495
2496         delayed_refs = &trans->transaction->delayed_refs;
2497         INIT_LIST_HEAD(&cluster);
2498         if (count == 0) {
2499                 count = delayed_refs->num_entries * 2;
2500                 run_most = 1;
2501         }
2502
2503         if (!run_all && !run_most) {
2504                 int old;
2505                 int seq = atomic_read(&delayed_refs->ref_seq);
2506
2507 progress:
2508                 old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2509                 if (old) {
2510                         DEFINE_WAIT(__wait);
2511                         if (delayed_refs->num_entries < 16348)
2512                                 return 0;
2513
2514                         prepare_to_wait(&delayed_refs->wait, &__wait,
2515                                         TASK_UNINTERRUPTIBLE);
2516
2517                         old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2518                         if (old) {
2519                                 schedule();
2520                                 finish_wait(&delayed_refs->wait, &__wait);
2521
2522                                 if (!refs_newer(delayed_refs, seq, 256))
2523                                         goto progress;
2524                                 else
2525                                         return 0;
2526                         } else {
2527                                 finish_wait(&delayed_refs->wait, &__wait);
2528                                 goto again;
2529                         }
2530                 }
2531
2532         } else {
2533                 atomic_inc(&delayed_refs->procs_running_refs);
2534         }
2535
2536 again:
2537         loops = 0;
2538         spin_lock(&delayed_refs->lock);
2539
2540 #ifdef SCRAMBLE_DELAYED_REFS
2541         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2542 #endif
2543
2544         while (1) {
2545                 if (!(run_all || run_most) &&
2546                     delayed_refs->num_heads_ready < 64)
2547                         break;
2548
2549                 /*
2550                  * go find something we can process in the rbtree.  We start at
2551                  * the beginning of the tree, and then build a cluster
2552                  * of refs to process starting at the first one we are able to
2553                  * lock
2554                  */
2555                 delayed_start = delayed_refs->run_delayed_start;
2556                 ret = btrfs_find_ref_cluster(trans, &cluster,
2557                                              delayed_refs->run_delayed_start);
2558                 if (ret)
2559                         break;
2560
2561                 ret = run_clustered_refs(trans, root, &cluster);
2562                 if (ret < 0) {
2563                         btrfs_release_ref_cluster(&cluster);
2564                         spin_unlock(&delayed_refs->lock);
2565                         btrfs_abort_transaction(trans, root, ret);
2566                         atomic_dec(&delayed_refs->procs_running_refs);
2567                         return ret;
2568                 }
2569
2570                 atomic_add(ret, &delayed_refs->ref_seq);
2571
2572                 count -= min_t(unsigned long, ret, count);
2573
2574                 if (count == 0)
2575                         break;
2576
2577                 if (delayed_start >= delayed_refs->run_delayed_start) {
2578                         if (loops == 0) {
2579                                 /*
2580                                  * btrfs_find_ref_cluster looped. let's do one
2581                                  * more cycle. if we don't run any delayed ref
2582                                  * during that cycle (because we can't because
2583                                  * all of them are blocked), bail out.
2584                                  */
2585                                 loops = 1;
2586                         } else {
2587                                 /*
2588                                  * no runnable refs left, stop trying
2589                                  */
2590                                 BUG_ON(run_all);
2591                                 break;
2592                         }
2593                 }
2594                 if (ret) {
2595                         /* refs were run, let's reset staleness detection */
2596                         loops = 0;
2597                 }
2598         }
2599
2600         if (run_all) {
2601                 if (!list_empty(&trans->new_bgs)) {
2602                         spin_unlock(&delayed_refs->lock);
2603                         btrfs_create_pending_block_groups(trans, root);
2604                         spin_lock(&delayed_refs->lock);
2605                 }
2606
2607                 node = rb_first(&delayed_refs->root);
2608                 if (!node)
2609                         goto out;
2610                 count = (unsigned long)-1;
2611
2612                 while (node) {
2613                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2614                                        rb_node);
2615                         if (btrfs_delayed_ref_is_head(ref)) {
2616                                 struct btrfs_delayed_ref_head *head;
2617
2618                                 head = btrfs_delayed_node_to_head(ref);
2619                                 atomic_inc(&ref->refs);
2620
2621                                 spin_unlock(&delayed_refs->lock);
2622                                 /*
2623                                  * Mutex was contended, block until it's
2624                                  * released and try again
2625                                  */
2626                                 mutex_lock(&head->mutex);
2627                                 mutex_unlock(&head->mutex);
2628
2629                                 btrfs_put_delayed_ref(ref);
2630                                 cond_resched();
2631                                 goto again;
2632                         }
2633                         node = rb_next(node);
2634                 }
2635                 spin_unlock(&delayed_refs->lock);
2636                 schedule_timeout(1);
2637                 goto again;
2638         }
2639 out:
2640         atomic_dec(&delayed_refs->procs_running_refs);
2641         smp_mb();
2642         if (waitqueue_active(&delayed_refs->wait))
2643                 wake_up(&delayed_refs->wait);
2644
2645         spin_unlock(&delayed_refs->lock);
2646         assert_qgroups_uptodate(trans);
2647         return 0;
2648 }
2649
2650 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2651                                 struct btrfs_root *root,
2652                                 u64 bytenr, u64 num_bytes, u64 flags,
2653                                 int is_data)
2654 {
2655         struct btrfs_delayed_extent_op *extent_op;
2656         int ret;
2657
2658         extent_op = btrfs_alloc_delayed_extent_op();
2659         if (!extent_op)
2660                 return -ENOMEM;
2661
2662         extent_op->flags_to_set = flags;
2663         extent_op->update_flags = 1;
2664         extent_op->update_key = 0;
2665         extent_op->is_data = is_data ? 1 : 0;
2666
2667         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2668                                           num_bytes, extent_op);
2669         if (ret)
2670                 btrfs_free_delayed_extent_op(extent_op);
2671         return ret;
2672 }
2673
2674 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2675                                       struct btrfs_root *root,
2676                                       struct btrfs_path *path,
2677                                       u64 objectid, u64 offset, u64 bytenr)
2678 {
2679         struct btrfs_delayed_ref_head *head;
2680         struct btrfs_delayed_ref_node *ref;
2681         struct btrfs_delayed_data_ref *data_ref;
2682         struct btrfs_delayed_ref_root *delayed_refs;
2683         struct rb_node *node;
2684         int ret = 0;
2685
2686         ret = -ENOENT;
2687         delayed_refs = &trans->transaction->delayed_refs;
2688         spin_lock(&delayed_refs->lock);
2689         head = btrfs_find_delayed_ref_head(trans, bytenr);
2690         if (!head)
2691                 goto out;
2692
2693         if (!mutex_trylock(&head->mutex)) {
2694                 atomic_inc(&head->node.refs);
2695                 spin_unlock(&delayed_refs->lock);
2696
2697                 btrfs_release_path(path);
2698
2699                 /*
2700                  * Mutex was contended, block until it's released and let
2701                  * caller try again
2702                  */
2703                 mutex_lock(&head->mutex);
2704                 mutex_unlock(&head->mutex);
2705                 btrfs_put_delayed_ref(&head->node);
2706                 return -EAGAIN;
2707         }
2708
2709         node = rb_prev(&head->node.rb_node);
2710         if (!node)
2711                 goto out_unlock;
2712
2713         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2714
2715         if (ref->bytenr != bytenr)
2716                 goto out_unlock;
2717
2718         ret = 1;
2719         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2720                 goto out_unlock;
2721
2722         data_ref = btrfs_delayed_node_to_data_ref(ref);
2723
2724         node = rb_prev(node);
2725         if (node) {
2726                 int seq = ref->seq;
2727
2728                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2729                 if (ref->bytenr == bytenr && ref->seq == seq)
2730                         goto out_unlock;
2731         }
2732
2733         if (data_ref->root != root->root_key.objectid ||
2734             data_ref->objectid != objectid || data_ref->offset != offset)
2735                 goto out_unlock;
2736
2737         ret = 0;
2738 out_unlock:
2739         mutex_unlock(&head->mutex);
2740 out:
2741         spin_unlock(&delayed_refs->lock);
2742         return ret;
2743 }
2744
2745 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2746                                         struct btrfs_root *root,
2747                                         struct btrfs_path *path,
2748                                         u64 objectid, u64 offset, u64 bytenr)
2749 {
2750         struct btrfs_root *extent_root = root->fs_info->extent_root;
2751         struct extent_buffer *leaf;
2752         struct btrfs_extent_data_ref *ref;
2753         struct btrfs_extent_inline_ref *iref;
2754         struct btrfs_extent_item *ei;
2755         struct btrfs_key key;
2756         u32 item_size;
2757         int ret;
2758
2759         key.objectid = bytenr;
2760         key.offset = (u64)-1;
2761         key.type = BTRFS_EXTENT_ITEM_KEY;
2762
2763         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2764         if (ret < 0)
2765                 goto out;
2766         BUG_ON(ret == 0); /* Corruption */
2767
2768         ret = -ENOENT;
2769         if (path->slots[0] == 0)
2770                 goto out;
2771
2772         path->slots[0]--;
2773         leaf = path->nodes[0];
2774         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2775
2776         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2777                 goto out;
2778
2779         ret = 1;
2780         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2781 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2782         if (item_size < sizeof(*ei)) {
2783                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2784                 goto out;
2785         }
2786 #endif
2787         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2788
2789         if (item_size != sizeof(*ei) +
2790             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2791                 goto out;
2792
2793         if (btrfs_extent_generation(leaf, ei) <=
2794             btrfs_root_last_snapshot(&root->root_item))
2795                 goto out;
2796
2797         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2798         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2799             BTRFS_EXTENT_DATA_REF_KEY)
2800                 goto out;
2801
2802         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2803         if (btrfs_extent_refs(leaf, ei) !=
2804             btrfs_extent_data_ref_count(leaf, ref) ||
2805             btrfs_extent_data_ref_root(leaf, ref) !=
2806             root->root_key.objectid ||
2807             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2808             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2809                 goto out;
2810
2811         ret = 0;
2812 out:
2813         return ret;
2814 }
2815
2816 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2817                           struct btrfs_root *root,
2818                           u64 objectid, u64 offset, u64 bytenr)
2819 {
2820         struct btrfs_path *path;
2821         int ret;
2822         int ret2;
2823
2824         path = btrfs_alloc_path();
2825         if (!path)
2826                 return -ENOENT;
2827
2828         do {
2829                 ret = check_committed_ref(trans, root, path, objectid,
2830                                           offset, bytenr);
2831                 if (ret && ret != -ENOENT)
2832                         goto out;
2833
2834                 ret2 = check_delayed_ref(trans, root, path, objectid,
2835                                          offset, bytenr);
2836         } while (ret2 == -EAGAIN);
2837
2838         if (ret2 && ret2 != -ENOENT) {
2839                 ret = ret2;
2840                 goto out;
2841         }
2842
2843         if (ret != -ENOENT || ret2 != -ENOENT)
2844                 ret = 0;
2845 out:
2846         btrfs_free_path(path);
2847         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2848                 WARN_ON(ret > 0);
2849         return ret;
2850 }
2851
2852 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2853                            struct btrfs_root *root,
2854                            struct extent_buffer *buf,
2855                            int full_backref, int inc, int for_cow)
2856 {
2857         u64 bytenr;
2858         u64 num_bytes;
2859         u64 parent;
2860         u64 ref_root;
2861         u32 nritems;
2862         struct btrfs_key key;
2863         struct btrfs_file_extent_item *fi;
2864         int i;
2865         int level;
2866         int ret = 0;
2867         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2868                             u64, u64, u64, u64, u64, u64, int);
2869
2870         ref_root = btrfs_header_owner(buf);
2871         nritems = btrfs_header_nritems(buf);
2872         level = btrfs_header_level(buf);
2873
2874         if (!root->ref_cows && level == 0)
2875                 return 0;
2876
2877         if (inc)
2878                 process_func = btrfs_inc_extent_ref;
2879         else
2880                 process_func = btrfs_free_extent;
2881
2882         if (full_backref)
2883                 parent = buf->start;
2884         else
2885                 parent = 0;
2886
2887         for (i = 0; i < nritems; i++) {
2888                 if (level == 0) {
2889                         btrfs_item_key_to_cpu(buf, &key, i);
2890                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2891                                 continue;
2892                         fi = btrfs_item_ptr(buf, i,
2893                                             struct btrfs_file_extent_item);
2894                         if (btrfs_file_extent_type(buf, fi) ==
2895                             BTRFS_FILE_EXTENT_INLINE)
2896                                 continue;
2897                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2898                         if (bytenr == 0)
2899                                 continue;
2900
2901                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2902                         key.offset -= btrfs_file_extent_offset(buf, fi);
2903                         ret = process_func(trans, root, bytenr, num_bytes,
2904                                            parent, ref_root, key.objectid,
2905                                            key.offset, for_cow);
2906                         if (ret)
2907                                 goto fail;
2908                 } else {
2909                         bytenr = btrfs_node_blockptr(buf, i);
2910                         num_bytes = btrfs_level_size(root, level - 1);
2911                         ret = process_func(trans, root, bytenr, num_bytes,
2912                                            parent, ref_root, level - 1, 0,
2913                                            for_cow);
2914                         if (ret)
2915                                 goto fail;
2916                 }
2917         }
2918         return 0;
2919 fail:
2920         return ret;
2921 }
2922
2923 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2924                   struct extent_buffer *buf, int full_backref, int for_cow)
2925 {
2926         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
2927 }
2928
2929 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2930                   struct extent_buffer *buf, int full_backref, int for_cow)
2931 {
2932         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
2933 }
2934
2935 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2936                                  struct btrfs_root *root,
2937                                  struct btrfs_path *path,
2938                                  struct btrfs_block_group_cache *cache)
2939 {
2940         int ret;
2941         struct btrfs_root *extent_root = root->fs_info->extent_root;
2942         unsigned long bi;
2943         struct extent_buffer *leaf;
2944
2945         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2946         if (ret < 0)
2947                 goto fail;
2948         BUG_ON(ret); /* Corruption */
2949
2950         leaf = path->nodes[0];
2951         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2952         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2953         btrfs_mark_buffer_dirty(leaf);
2954         btrfs_release_path(path);
2955 fail:
2956         if (ret) {
2957                 btrfs_abort_transaction(trans, root, ret);
2958                 return ret;
2959         }
2960         return 0;
2961
2962 }
2963
2964 static struct btrfs_block_group_cache *
2965 next_block_group(struct btrfs_root *root,
2966                  struct btrfs_block_group_cache *cache)
2967 {
2968         struct rb_node *node;
2969         spin_lock(&root->fs_info->block_group_cache_lock);
2970         node = rb_next(&cache->cache_node);
2971         btrfs_put_block_group(cache);
2972         if (node) {
2973                 cache = rb_entry(node, struct btrfs_block_group_cache,
2974                                  cache_node);
2975                 btrfs_get_block_group(cache);
2976         } else
2977                 cache = NULL;
2978         spin_unlock(&root->fs_info->block_group_cache_lock);
2979         return cache;
2980 }
2981
2982 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2983                             struct btrfs_trans_handle *trans,
2984                             struct btrfs_path *path)
2985 {
2986         struct btrfs_root *root = block_group->fs_info->tree_root;
2987         struct inode *inode = NULL;
2988         u64 alloc_hint = 0;
2989         int dcs = BTRFS_DC_ERROR;
2990         int num_pages = 0;
2991         int retries = 0;
2992         int ret = 0;
2993
2994         /*
2995          * If this block group is smaller than 100 megs don't bother caching the
2996          * block group.
2997          */
2998         if (block_group->key.offset < (100 * 1024 * 1024)) {
2999                 spin_lock(&block_group->lock);
3000                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3001                 spin_unlock(&block_group->lock);
3002                 return 0;
3003         }
3004
3005 again:
3006         inode = lookup_free_space_inode(root, block_group, path);
3007         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3008                 ret = PTR_ERR(inode);
3009                 btrfs_release_path(path);
3010                 goto out;
3011         }
3012
3013         if (IS_ERR(inode)) {
3014                 BUG_ON(retries);
3015                 retries++;
3016
3017                 if (block_group->ro)
3018                         goto out_free;
3019
3020                 ret = create_free_space_inode(root, trans, block_group, path);
3021                 if (ret)
3022                         goto out_free;
3023                 goto again;
3024         }
3025
3026         /* We've already setup this transaction, go ahead and exit */
3027         if (block_group->cache_generation == trans->transid &&
3028             i_size_read(inode)) {
3029                 dcs = BTRFS_DC_SETUP;
3030                 goto out_put;
3031         }
3032
3033         /*
3034          * We want to set the generation to 0, that way if anything goes wrong
3035          * from here on out we know not to trust this cache when we load up next
3036          * time.
3037          */
3038         BTRFS_I(inode)->generation = 0;
3039         ret = btrfs_update_inode(trans, root, inode);
3040         WARN_ON(ret);
3041
3042         if (i_size_read(inode) > 0) {
3043                 ret = btrfs_truncate_free_space_cache(root, trans, path,
3044                                                       inode);
3045                 if (ret)
3046                         goto out_put;
3047         }
3048
3049         spin_lock(&block_group->lock);
3050         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3051             !btrfs_test_opt(root, SPACE_CACHE)) {
3052                 /*
3053                  * don't bother trying to write stuff out _if_
3054                  * a) we're not cached,
3055                  * b) we're with nospace_cache mount option.
3056                  */
3057                 dcs = BTRFS_DC_WRITTEN;
3058                 spin_unlock(&block_group->lock);
3059                 goto out_put;
3060         }
3061         spin_unlock(&block_group->lock);
3062
3063         /*
3064          * Try to preallocate enough space based on how big the block group is.
3065          * Keep in mind this has to include any pinned space which could end up
3066          * taking up quite a bit since it's not folded into the other space
3067          * cache.
3068          */
3069         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3070         if (!num_pages)
3071                 num_pages = 1;
3072
3073         num_pages *= 16;
3074         num_pages *= PAGE_CACHE_SIZE;
3075
3076         ret = btrfs_check_data_free_space(inode, num_pages);
3077         if (ret)
3078                 goto out_put;
3079
3080         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3081                                               num_pages, num_pages,
3082                                               &alloc_hint);
3083         if (!ret)
3084                 dcs = BTRFS_DC_SETUP;
3085         btrfs_free_reserved_data_space(inode, num_pages);
3086
3087 out_put:
3088         iput(inode);
3089 out_free:
3090         btrfs_release_path(path);
3091 out:
3092         spin_lock(&block_group->lock);
3093         if (!ret && dcs == BTRFS_DC_SETUP)
3094                 block_group->cache_generation = trans->transid;
3095         block_group->disk_cache_state = dcs;
3096         spin_unlock(&block_group->lock);
3097
3098         return ret;
3099 }
3100
3101 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3102                                    struct btrfs_root *root)
3103 {
3104         struct btrfs_block_group_cache *cache;
3105         int err = 0;
3106         struct btrfs_path *path;
3107         u64 last = 0;
3108
3109         path = btrfs_alloc_path();
3110         if (!path)
3111                 return -ENOMEM;
3112
3113 again:
3114         while (1) {
3115                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3116                 while (cache) {
3117                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3118                                 break;
3119                         cache = next_block_group(root, cache);
3120                 }
3121                 if (!cache) {
3122                         if (last == 0)
3123                                 break;
3124                         last = 0;
3125                         continue;
3126                 }
3127                 err = cache_save_setup(cache, trans, path);
3128                 last = cache->key.objectid + cache->key.offset;
3129                 btrfs_put_block_group(cache);
3130         }
3131
3132         while (1) {
3133                 if (last == 0) {
3134                         err = btrfs_run_delayed_refs(trans, root,
3135                                                      (unsigned long)-1);
3136                         if (err) /* File system offline */
3137                                 goto out;
3138                 }
3139
3140                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3141                 while (cache) {
3142                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3143                                 btrfs_put_block_group(cache);
3144                                 goto again;
3145                         }
3146
3147                         if (cache->dirty)
3148                                 break;
3149                         cache = next_block_group(root, cache);
3150                 }
3151                 if (!cache) {
3152                         if (last == 0)
3153                                 break;
3154                         last = 0;
3155                         continue;
3156                 }
3157
3158                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3159                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3160                 cache->dirty = 0;
3161                 last = cache->key.objectid + cache->key.offset;
3162
3163                 err = write_one_cache_group(trans, root, path, cache);
3164                 if (err) /* File system offline */
3165                         goto out;
3166
3167                 btrfs_put_block_group(cache);
3168         }
3169
3170         while (1) {
3171                 /*
3172                  * I don't think this is needed since we're just marking our
3173                  * preallocated extent as written, but just in case it can't
3174                  * hurt.
3175                  */
3176                 if (last == 0) {
3177                         err = btrfs_run_delayed_refs(trans, root,
3178                                                      (unsigned long)-1);
3179                         if (err) /* File system offline */
3180                                 goto out;
3181                 }
3182
3183                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3184                 while (cache) {
3185                         /*
3186                          * Really this shouldn't happen, but it could if we
3187                          * couldn't write the entire preallocated extent and
3188                          * splitting the extent resulted in a new block.
3189                          */
3190                         if (cache->dirty) {
3191                                 btrfs_put_block_group(cache);
3192                                 goto again;
3193                         }
3194                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3195                                 break;
3196                         cache = next_block_group(root, cache);
3197                 }
3198                 if (!cache) {
3199                         if (last == 0)
3200                                 break;
3201                         last = 0;
3202                         continue;
3203                 }
3204
3205                 err = btrfs_write_out_cache(root, trans, cache, path);
3206
3207                 /*
3208                  * If we didn't have an error then the cache state is still
3209                  * NEED_WRITE, so we can set it to WRITTEN.
3210                  */
3211                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3212                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3213                 last = cache->key.objectid + cache->key.offset;
3214                 btrfs_put_block_group(cache);
3215         }
3216 out:
3217
3218         btrfs_free_path(path);
3219         return err;
3220 }
3221
3222 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3223 {
3224         struct btrfs_block_group_cache *block_group;
3225         int readonly = 0;
3226
3227         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3228         if (!block_group || block_group->ro)
3229                 readonly = 1;
3230         if (block_group)
3231                 btrfs_put_block_group(block_group);
3232         return readonly;
3233 }
3234
3235 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3236                              u64 total_bytes, u64 bytes_used,
3237                              struct btrfs_space_info **space_info)
3238 {
3239         struct btrfs_space_info *found;
3240         int i;
3241         int factor;
3242
3243         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3244                      BTRFS_BLOCK_GROUP_RAID10))
3245                 factor = 2;
3246         else
3247                 factor = 1;
3248
3249         found = __find_space_info(info, flags);
3250         if (found) {
3251                 spin_lock(&found->lock);
3252                 found->total_bytes += total_bytes;
3253                 found->disk_total += total_bytes * factor;
3254                 found->bytes_used += bytes_used;
3255                 found->disk_used += bytes_used * factor;
3256                 found->full = 0;
3257                 spin_unlock(&found->lock);
3258                 *space_info = found;
3259                 return 0;
3260         }
3261         found = kzalloc(sizeof(*found), GFP_NOFS);
3262         if (!found)
3263                 return -ENOMEM;
3264
3265         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3266                 INIT_LIST_HEAD(&found->block_groups[i]);
3267         init_rwsem(&found->groups_sem);
3268         spin_lock_init(&found->lock);
3269         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3270         found->total_bytes = total_bytes;
3271         found->disk_total = total_bytes * factor;
3272         found->bytes_used = bytes_used;
3273         found->disk_used = bytes_used * factor;
3274         found->bytes_pinned = 0;
3275         found->bytes_reserved = 0;
3276         found->bytes_readonly = 0;
3277         found->bytes_may_use = 0;
3278         found->full = 0;
3279         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3280         found->chunk_alloc = 0;
3281         found->flush = 0;
3282         init_waitqueue_head(&found->wait);
3283         *space_info = found;
3284         list_add_rcu(&found->list, &info->space_info);
3285         if (flags & BTRFS_BLOCK_GROUP_DATA)
3286                 info->data_sinfo = found;
3287         return 0;
3288 }
3289
3290 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3291 {
3292         u64 extra_flags = chunk_to_extended(flags) &
3293                                 BTRFS_EXTENDED_PROFILE_MASK;
3294
3295         write_seqlock(&fs_info->profiles_lock);
3296         if (flags & BTRFS_BLOCK_GROUP_DATA)
3297                 fs_info->avail_data_alloc_bits |= extra_flags;
3298         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3299                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3300         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3301                 fs_info->avail_system_alloc_bits |= extra_flags;
3302         write_sequnlock(&fs_info->profiles_lock);
3303 }
3304
3305 /*
3306  * returns target flags in extended format or 0 if restripe for this
3307  * chunk_type is not in progress
3308  *
3309  * should be called with either volume_mutex or balance_lock held
3310  */
3311 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3312 {
3313         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3314         u64 target = 0;
3315
3316         if (!bctl)
3317                 return 0;
3318
3319         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3320             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3321                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3322         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3323                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3324                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3325         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3326                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3327                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3328         }
3329
3330         return target;
3331 }
3332
3333 /*
3334  * @flags: available profiles in extended format (see ctree.h)
3335  *
3336  * Returns reduced profile in chunk format.  If profile changing is in
3337  * progress (either running or paused) picks the target profile (if it's
3338  * already available), otherwise falls back to plain reducing.
3339  */
3340 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3341 {
3342         /*
3343          * we add in the count of missing devices because we want
3344          * to make sure that any RAID levels on a degraded FS
3345          * continue to be honored.
3346          */
3347         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3348                 root->fs_info->fs_devices->missing_devices;
3349         u64 target;
3350         u64 tmp;
3351
3352         /*
3353          * see if restripe for this chunk_type is in progress, if so
3354          * try to reduce to the target profile
3355          */
3356         spin_lock(&root->fs_info->balance_lock);
3357         target = get_restripe_target(root->fs_info, flags);
3358         if (target) {
3359                 /* pick target profile only if it's already available */
3360                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3361                         spin_unlock(&root->fs_info->balance_lock);
3362                         return extended_to_chunk(target);
3363                 }
3364         }
3365         spin_unlock(&root->fs_info->balance_lock);
3366
3367         /* First, mask out the RAID levels which aren't possible */
3368         if (num_devices == 1)
3369                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3370                            BTRFS_BLOCK_GROUP_RAID5);
3371         if (num_devices < 3)
3372                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3373         if (num_devices < 4)
3374                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3375
3376         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3377                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3378                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3379         flags &= ~tmp;
3380
3381         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3382                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3383         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3384                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3385         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3386                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3387         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3388                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3389         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3390                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3391
3392         return extended_to_chunk(flags | tmp);
3393 }
3394
3395 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3396 {
3397         unsigned seq;
3398
3399         do {
3400                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3401
3402                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3403                         flags |= root->fs_info->avail_data_alloc_bits;
3404                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3405                         flags |= root->fs_info->avail_system_alloc_bits;
3406                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3407                         flags |= root->fs_info->avail_metadata_alloc_bits;
3408         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3409
3410         return btrfs_reduce_alloc_profile(root, flags);
3411 }
3412
3413 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3414 {
3415         u64 flags;
3416         u64 ret;
3417
3418         if (data)
3419                 flags = BTRFS_BLOCK_GROUP_DATA;
3420         else if (root == root->fs_info->chunk_root)
3421                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3422         else
3423                 flags = BTRFS_BLOCK_GROUP_METADATA;
3424
3425         ret = get_alloc_profile(root, flags);
3426         return ret;
3427 }
3428
3429 /*
3430  * This will check the space that the inode allocates from to make sure we have
3431  * enough space for bytes.
3432  */
3433 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3434 {
3435         struct btrfs_space_info *data_sinfo;
3436         struct btrfs_root *root = BTRFS_I(inode)->root;
3437         struct btrfs_fs_info *fs_info = root->fs_info;
3438         u64 used;
3439         int ret = 0, committed = 0, alloc_chunk = 1;
3440
3441         /* make sure bytes are sectorsize aligned */
3442         bytes = ALIGN(bytes, root->sectorsize);
3443
3444         if (root == root->fs_info->tree_root ||
3445             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3446                 alloc_chunk = 0;
3447                 committed = 1;
3448         }
3449
3450         data_sinfo = fs_info->data_sinfo;
3451         if (!data_sinfo)
3452                 goto alloc;
3453
3454 again:
3455         /* make sure we have enough space to handle the data first */
3456         spin_lock(&data_sinfo->lock);
3457         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3458                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3459                 data_sinfo->bytes_may_use;
3460
3461         if (used + bytes > data_sinfo->total_bytes) {
3462                 struct btrfs_trans_handle *trans;
3463
3464                 /*
3465                  * if we don't have enough free bytes in this space then we need
3466                  * to alloc a new chunk.
3467                  */
3468                 if (!data_sinfo->full && alloc_chunk) {
3469                         u64 alloc_target;
3470
3471                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3472                         spin_unlock(&data_sinfo->lock);
3473 alloc:
3474                         alloc_target = btrfs_get_alloc_profile(root, 1);
3475                         trans = btrfs_join_transaction(root);
3476                         if (IS_ERR(trans))
3477                                 return PTR_ERR(trans);
3478
3479                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3480                                              alloc_target,
3481                                              CHUNK_ALLOC_NO_FORCE);
3482                         btrfs_end_transaction(trans, root);
3483                         if (ret < 0) {
3484                                 if (ret != -ENOSPC)
3485                                         return ret;
3486                                 else
3487                                         goto commit_trans;
3488                         }
3489
3490                         if (!data_sinfo)
3491                                 data_sinfo = fs_info->data_sinfo;
3492
3493                         goto again;
3494                 }
3495
3496                 /*
3497                  * If we have less pinned bytes than we want to allocate then
3498                  * don't bother committing the transaction, it won't help us.
3499                  */
3500                 if (data_sinfo->bytes_pinned < bytes)
3501                         committed = 1;
3502                 spin_unlock(&data_sinfo->lock);
3503
3504                 /* commit the current transaction and try again */
3505 commit_trans:
3506                 if (!committed &&
3507                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3508                         committed = 1;
3509                         trans = btrfs_join_transaction(root);
3510                         if (IS_ERR(trans))
3511                                 return PTR_ERR(trans);
3512                         ret = btrfs_commit_transaction(trans, root);
3513                         if (ret)
3514                                 return ret;
3515                         goto again;
3516                 }
3517
3518                 return -ENOSPC;
3519         }
3520         data_sinfo->bytes_may_use += bytes;
3521         trace_btrfs_space_reservation(root->fs_info, "space_info",
3522                                       data_sinfo->flags, bytes, 1);
3523         spin_unlock(&data_sinfo->lock);
3524
3525         return 0;
3526 }
3527
3528 /*
3529  * Called if we need to clear a data reservation for this inode.
3530  */
3531 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3532 {
3533         struct btrfs_root *root = BTRFS_I(inode)->root;
3534         struct btrfs_space_info *data_sinfo;
3535
3536         /* make sure bytes are sectorsize aligned */
3537         bytes = ALIGN(bytes, root->sectorsize);
3538
3539         data_sinfo = root->fs_info->data_sinfo;
3540         spin_lock(&data_sinfo->lock);
3541         data_sinfo->bytes_may_use -= bytes;
3542         trace_btrfs_space_reservation(root->fs_info, "space_info",
3543                                       data_sinfo->flags, bytes, 0);
3544         spin_unlock(&data_sinfo->lock);
3545 }
3546
3547 static void force_metadata_allocation(struct btrfs_fs_info *info)
3548 {
3549         struct list_head *head = &info->space_info;
3550         struct btrfs_space_info *found;
3551
3552         rcu_read_lock();
3553         list_for_each_entry_rcu(found, head, list) {
3554                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3555                         found->force_alloc = CHUNK_ALLOC_FORCE;
3556         }
3557         rcu_read_unlock();
3558 }
3559
3560 static int should_alloc_chunk(struct btrfs_root *root,
3561                               struct btrfs_space_info *sinfo, int force)
3562 {
3563         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3564         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3565         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3566         u64 thresh;
3567
3568         if (force == CHUNK_ALLOC_FORCE)
3569                 return 1;
3570
3571         /*
3572          * We need to take into account the global rsv because for all intents
3573          * and purposes it's used space.  Don't worry about locking the
3574          * global_rsv, it doesn't change except when the transaction commits.
3575          */
3576         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3577                 num_allocated += global_rsv->size;
3578
3579         /*
3580          * in limited mode, we want to have some free space up to
3581          * about 1% of the FS size.
3582          */
3583         if (force == CHUNK_ALLOC_LIMITED) {
3584                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3585                 thresh = max_t(u64, 64 * 1024 * 1024,
3586                                div_factor_fine(thresh, 1));
3587
3588                 if (num_bytes - num_allocated < thresh)
3589                         return 1;
3590         }
3591
3592         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3593                 return 0;
3594         return 1;
3595 }
3596
3597 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3598 {
3599         u64 num_dev;
3600
3601         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3602                     BTRFS_BLOCK_GROUP_RAID0 |
3603                     BTRFS_BLOCK_GROUP_RAID5 |
3604                     BTRFS_BLOCK_GROUP_RAID6))
3605                 num_dev = root->fs_info->fs_devices->rw_devices;
3606         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3607                 num_dev = 2;
3608         else
3609                 num_dev = 1;    /* DUP or single */
3610
3611         /* metadata for updaing devices and chunk tree */
3612         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3613 }
3614
3615 static void check_system_chunk(struct btrfs_trans_handle *trans,
3616                                struct btrfs_root *root, u64 type)
3617 {
3618         struct btrfs_space_info *info;
3619         u64 left;
3620         u64 thresh;
3621
3622         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3623         spin_lock(&info->lock);
3624         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3625                 info->bytes_reserved - info->bytes_readonly;
3626         spin_unlock(&info->lock);
3627
3628         thresh = get_system_chunk_thresh(root, type);
3629         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3630                 printk(KERN_INFO "left=%llu, need=%llu, flags=%llu\n",
3631                        left, thresh, type);
3632                 dump_space_info(info, 0, 0);
3633         }
3634
3635         if (left < thresh) {
3636                 u64 flags;
3637
3638                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3639                 btrfs_alloc_chunk(trans, root, flags);
3640         }
3641 }
3642
3643 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3644                           struct btrfs_root *extent_root, u64 flags, int force)
3645 {
3646         struct btrfs_space_info *space_info;
3647         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3648         int wait_for_alloc = 0;
3649         int ret = 0;
3650
3651         /* Don't re-enter if we're already allocating a chunk */
3652         if (trans->allocating_chunk)
3653                 return -ENOSPC;
3654
3655         space_info = __find_space_info(extent_root->fs_info, flags);
3656         if (!space_info) {
3657                 ret = update_space_info(extent_root->fs_info, flags,
3658                                         0, 0, &space_info);
3659                 BUG_ON(ret); /* -ENOMEM */
3660         }
3661         BUG_ON(!space_info); /* Logic error */
3662
3663 again:
3664         spin_lock(&space_info->lock);
3665         if (force < space_info->force_alloc)
3666                 force = space_info->force_alloc;
3667         if (space_info->full) {
3668                 spin_unlock(&space_info->lock);
3669                 return 0;
3670         }
3671
3672         if (!should_alloc_chunk(extent_root, space_info, force)) {
3673                 spin_unlock(&space_info->lock);
3674                 return 0;
3675         } else if (space_info->chunk_alloc) {
3676                 wait_for_alloc = 1;
3677         } else {
3678                 space_info->chunk_alloc = 1;
3679         }
3680
3681         spin_unlock(&space_info->lock);
3682
3683         mutex_lock(&fs_info->chunk_mutex);
3684
3685         /*
3686          * The chunk_mutex is held throughout the entirety of a chunk
3687          * allocation, so once we've acquired the chunk_mutex we know that the
3688          * other guy is done and we need to recheck and see if we should
3689          * allocate.
3690          */
3691         if (wait_for_alloc) {
3692                 mutex_unlock(&fs_info->chunk_mutex);
3693                 wait_for_alloc = 0;
3694                 goto again;
3695         }
3696
3697         trans->allocating_chunk = true;
3698
3699         /*
3700          * If we have mixed data/metadata chunks we want to make sure we keep
3701          * allocating mixed chunks instead of individual chunks.
3702          */
3703         if (btrfs_mixed_space_info(space_info))
3704                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3705
3706         /*
3707          * if we're doing a data chunk, go ahead and make sure that
3708          * we keep a reasonable number of metadata chunks allocated in the
3709          * FS as well.
3710          */
3711         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3712                 fs_info->data_chunk_allocations++;
3713                 if (!(fs_info->data_chunk_allocations %
3714                       fs_info->metadata_ratio))
3715                         force_metadata_allocation(fs_info);
3716         }
3717
3718         /*
3719          * Check if we have enough space in SYSTEM chunk because we may need
3720          * to update devices.
3721          */
3722         check_system_chunk(trans, extent_root, flags);
3723
3724         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3725         trans->allocating_chunk = false;
3726
3727         spin_lock(&space_info->lock);
3728         if (ret < 0 && ret != -ENOSPC)
3729                 goto out;
3730         if (ret)
3731                 space_info->full = 1;
3732         else
3733                 ret = 1;
3734
3735         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3736 out:
3737         space_info->chunk_alloc = 0;
3738         spin_unlock(&space_info->lock);
3739         mutex_unlock(&fs_info->chunk_mutex);
3740         return ret;
3741 }
3742
3743 static int can_overcommit(struct btrfs_root *root,
3744                           struct btrfs_space_info *space_info, u64 bytes,
3745                           enum btrfs_reserve_flush_enum flush)
3746 {
3747         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3748         u64 profile = btrfs_get_alloc_profile(root, 0);
3749         u64 rsv_size = 0;
3750         u64 avail;
3751         u64 used;
3752         u64 to_add;
3753
3754         used = space_info->bytes_used + space_info->bytes_reserved +
3755                 space_info->bytes_pinned + space_info->bytes_readonly;
3756
3757         spin_lock(&global_rsv->lock);
3758         rsv_size = global_rsv->size;
3759         spin_unlock(&global_rsv->lock);
3760
3761         /*
3762          * We only want to allow over committing if we have lots of actual space
3763          * free, but if we don't have enough space to handle the global reserve
3764          * space then we could end up having a real enospc problem when trying
3765          * to allocate a chunk or some other such important allocation.
3766          */
3767         rsv_size <<= 1;
3768         if (used + rsv_size >= space_info->total_bytes)
3769                 return 0;
3770
3771         used += space_info->bytes_may_use;
3772
3773         spin_lock(&root->fs_info->free_chunk_lock);
3774         avail = root->fs_info->free_chunk_space;
3775         spin_unlock(&root->fs_info->free_chunk_lock);
3776
3777         /*
3778          * If we have dup, raid1 or raid10 then only half of the free
3779          * space is actually useable.  For raid56, the space info used
3780          * doesn't include the parity drive, so we don't have to
3781          * change the math
3782          */
3783         if (profile & (BTRFS_BLOCK_GROUP_DUP |
3784                        BTRFS_BLOCK_GROUP_RAID1 |
3785                        BTRFS_BLOCK_GROUP_RAID10))
3786                 avail >>= 1;
3787
3788         to_add = space_info->total_bytes;
3789
3790         /*
3791          * If we aren't flushing all things, let us overcommit up to
3792          * 1/2th of the space. If we can flush, don't let us overcommit
3793          * too much, let it overcommit up to 1/8 of the space.
3794          */
3795         if (flush == BTRFS_RESERVE_FLUSH_ALL)
3796                 to_add >>= 3;
3797         else
3798                 to_add >>= 1;
3799
3800         /*
3801          * Limit the overcommit to the amount of free space we could possibly
3802          * allocate for chunks.
3803          */
3804         to_add = min(avail, to_add);
3805
3806         if (used + bytes < space_info->total_bytes + to_add)
3807                 return 1;
3808         return 0;
3809 }
3810
3811 static inline int writeback_inodes_sb_nr_if_idle_safe(struct super_block *sb,
3812                                                       unsigned long nr_pages,
3813                                                       enum wb_reason reason)
3814 {
3815         /* the flusher is dealing with the dirty inodes now. */
3816         if (writeback_in_progress(sb->s_bdi))
3817                 return 1;
3818
3819         if (down_read_trylock(&sb->s_umount)) {
3820                 writeback_inodes_sb_nr(sb, nr_pages, reason);
3821                 up_read(&sb->s_umount);
3822                 return 1;
3823         }
3824
3825         return 0;
3826 }
3827
3828 void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
3829                                   unsigned long nr_pages)
3830 {
3831         struct super_block *sb = root->fs_info->sb;
3832         int started;
3833
3834         /* If we can not start writeback, just sync all the delalloc file. */
3835         started = writeback_inodes_sb_nr_if_idle_safe(sb, nr_pages,
3836                                                       WB_REASON_FS_FREE_SPACE);
3837         if (!started) {
3838                 /*
3839                  * We needn't worry the filesystem going from r/w to r/o though
3840                  * we don't acquire ->s_umount mutex, because the filesystem
3841                  * should guarantee the delalloc inodes list be empty after
3842                  * the filesystem is readonly(all dirty pages are written to
3843                  * the disk).
3844                  */
3845                 btrfs_start_delalloc_inodes(root, 0);
3846                 btrfs_wait_ordered_extents(root, 0);
3847         }
3848 }
3849
3850 /*
3851  * shrink metadata reservation for delalloc
3852  */
3853 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
3854                             bool wait_ordered)
3855 {
3856         struct btrfs_block_rsv *block_rsv;
3857         struct btrfs_space_info *space_info;
3858         struct btrfs_trans_handle *trans;
3859         u64 delalloc_bytes;
3860         u64 max_reclaim;
3861         long time_left;
3862         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3863         int loops = 0;
3864         enum btrfs_reserve_flush_enum flush;
3865
3866         trans = (struct btrfs_trans_handle *)current->journal_info;
3867         block_rsv = &root->fs_info->delalloc_block_rsv;
3868         space_info = block_rsv->space_info;
3869
3870         smp_mb();
3871         delalloc_bytes = percpu_counter_sum_positive(
3872                                                 &root->fs_info->delalloc_bytes);
3873         if (delalloc_bytes == 0) {
3874                 if (trans)
3875                         return;
3876                 btrfs_wait_ordered_extents(root, 0);
3877                 return;
3878         }
3879
3880         while (delalloc_bytes && loops < 3) {
3881                 max_reclaim = min(delalloc_bytes, to_reclaim);
3882                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
3883                 btrfs_writeback_inodes_sb_nr(root, nr_pages);
3884                 /*
3885                  * We need to wait for the async pages to actually start before
3886                  * we do anything.
3887                  */
3888                 wait_event(root->fs_info->async_submit_wait,
3889                            !atomic_read(&root->fs_info->async_delalloc_pages));
3890
3891                 if (!trans)
3892                         flush = BTRFS_RESERVE_FLUSH_ALL;
3893                 else
3894                         flush = BTRFS_RESERVE_NO_FLUSH;
3895                 spin_lock(&space_info->lock);
3896                 if (can_overcommit(root, space_info, orig, flush)) {
3897                         spin_unlock(&space_info->lock);
3898                         break;
3899                 }
3900                 spin_unlock(&space_info->lock);
3901
3902                 loops++;
3903                 if (wait_ordered && !trans) {
3904                         btrfs_wait_ordered_extents(root, 0);
3905                 } else {
3906                         time_left = schedule_timeout_killable(1);
3907                         if (time_left)
3908                                 break;
3909                 }
3910                 smp_mb();
3911                 delalloc_bytes = percpu_counter_sum_positive(
3912                                                 &root->fs_info->delalloc_bytes);
3913         }
3914 }
3915
3916 /**
3917  * maybe_commit_transaction - possibly commit the transaction if its ok to
3918  * @root - the root we're allocating for
3919  * @bytes - the number of bytes we want to reserve
3920  * @force - force the commit
3921  *
3922  * This will check to make sure that committing the transaction will actually
3923  * get us somewhere and then commit the transaction if it does.  Otherwise it
3924  * will return -ENOSPC.
3925  */
3926 static int may_commit_transaction(struct btrfs_root *root,
3927                                   struct btrfs_space_info *space_info,
3928                                   u64 bytes, int force)
3929 {
3930         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3931         struct btrfs_trans_handle *trans;
3932
3933         trans = (struct btrfs_trans_handle *)current->journal_info;
3934         if (trans)
3935                 return -EAGAIN;
3936
3937         if (force)
3938                 goto commit;
3939
3940         /* See if there is enough pinned space to make this reservation */
3941         spin_lock(&space_info->lock);
3942         if (space_info->bytes_pinned >= bytes) {
3943                 spin_unlock(&space_info->lock);
3944                 goto commit;
3945         }
3946         spin_unlock(&space_info->lock);
3947
3948         /*
3949          * See if there is some space in the delayed insertion reservation for
3950          * this reservation.
3951          */
3952         if (space_info != delayed_rsv->space_info)
3953                 return -ENOSPC;
3954
3955         spin_lock(&space_info->lock);
3956         spin_lock(&delayed_rsv->lock);
3957         if (space_info->bytes_pinned + delayed_rsv->size < bytes) {
3958                 spin_unlock(&delayed_rsv->lock);
3959                 spin_unlock(&space_info->lock);
3960                 return -ENOSPC;
3961         }
3962         spin_unlock(&delayed_rsv->lock);
3963         spin_unlock(&space_info->lock);
3964
3965 commit:
3966         trans = btrfs_join_transaction(root);
3967         if (IS_ERR(trans))
3968                 return -ENOSPC;
3969
3970         return btrfs_commit_transaction(trans, root);
3971 }
3972
3973 enum flush_state {
3974         FLUSH_DELAYED_ITEMS_NR  =       1,
3975         FLUSH_DELAYED_ITEMS     =       2,
3976         FLUSH_DELALLOC          =       3,
3977         FLUSH_DELALLOC_WAIT     =       4,
3978         ALLOC_CHUNK             =       5,
3979         COMMIT_TRANS            =       6,
3980 };
3981
3982 static int flush_space(struct btrfs_root *root,
3983                        struct btrfs_space_info *space_info, u64 num_bytes,
3984                        u64 orig_bytes, int state)
3985 {
3986         struct btrfs_trans_handle *trans;
3987         int nr;
3988         int ret = 0;
3989
3990         switch (state) {
3991         case FLUSH_DELAYED_ITEMS_NR:
3992         case FLUSH_DELAYED_ITEMS:
3993                 if (state == FLUSH_DELAYED_ITEMS_NR) {
3994                         u64 bytes = btrfs_calc_trans_metadata_size(root, 1);
3995
3996                         nr = (int)div64_u64(num_bytes, bytes);
3997                         if (!nr)
3998                                 nr = 1;
3999                         nr *= 2;
4000                 } else {
4001                         nr = -1;
4002                 }
4003                 trans = btrfs_join_transaction(root);
4004                 if (IS_ERR(trans)) {
4005                         ret = PTR_ERR(trans);
4006                         break;
4007                 }
4008                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4009                 btrfs_end_transaction(trans, root);
4010                 break;
4011         case FLUSH_DELALLOC:
4012         case FLUSH_DELALLOC_WAIT:
4013                 shrink_delalloc(root, num_bytes, orig_bytes,
4014                                 state == FLUSH_DELALLOC_WAIT);
4015                 break;
4016         case ALLOC_CHUNK:
4017                 trans = btrfs_join_transaction(root);
4018                 if (IS_ERR(trans)) {
4019                         ret = PTR_ERR(trans);
4020                         break;
4021                 }
4022                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4023                                      btrfs_get_alloc_profile(root, 0),
4024                                      CHUNK_ALLOC_NO_FORCE);
4025                 btrfs_end_transaction(trans, root);
4026                 if (ret == -ENOSPC)
4027                         ret = 0;
4028                 break;
4029         case COMMIT_TRANS:
4030                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4031                 break;
4032         default:
4033                 ret = -ENOSPC;
4034                 break;
4035         }
4036
4037         return ret;
4038 }
4039 /**
4040  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4041  * @root - the root we're allocating for
4042  * @block_rsv - the block_rsv we're allocating for
4043  * @orig_bytes - the number of bytes we want
4044  * @flush - whether or not we can flush to make our reservation
4045  *
4046  * This will reserve orgi_bytes number of bytes from the space info associated
4047  * with the block_rsv.  If there is not enough space it will make an attempt to
4048  * flush out space to make room.  It will do this by flushing delalloc if
4049  * possible or committing the transaction.  If flush is 0 then no attempts to
4050  * regain reservations will be made and this will fail if there is not enough
4051  * space already.
4052  */
4053 static int reserve_metadata_bytes(struct btrfs_root *root,
4054                                   struct btrfs_block_rsv *block_rsv,
4055                                   u64 orig_bytes,
4056                                   enum btrfs_reserve_flush_enum flush)
4057 {
4058         struct btrfs_space_info *space_info = block_rsv->space_info;
4059         u64 used;
4060         u64 num_bytes = orig_bytes;
4061         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4062         int ret = 0;
4063         bool flushing = false;
4064
4065 again:
4066         ret = 0;
4067         spin_lock(&space_info->lock);
4068         /*
4069          * We only want to wait if somebody other than us is flushing and we
4070          * are actually allowed to flush all things.
4071          */
4072         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4073                space_info->flush) {
4074                 spin_unlock(&space_info->lock);
4075                 /*
4076                  * If we have a trans handle we can't wait because the flusher
4077                  * may have to commit the transaction, which would mean we would
4078                  * deadlock since we are waiting for the flusher to finish, but
4079                  * hold the current transaction open.
4080                  */
4081                 if (current->journal_info)
4082                         return -EAGAIN;
4083                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4084                 /* Must have been killed, return */
4085                 if (ret)
4086                         return -EINTR;
4087
4088                 spin_lock(&space_info->lock);
4089         }
4090
4091         ret = -ENOSPC;
4092         used = space_info->bytes_used + space_info->bytes_reserved +
4093                 space_info->bytes_pinned + space_info->bytes_readonly +
4094                 space_info->bytes_may_use;
4095
4096         /*
4097          * The idea here is that we've not already over-reserved the block group
4098          * then we can go ahead and save our reservation first and then start
4099          * flushing if we need to.  Otherwise if we've already overcommitted
4100          * lets start flushing stuff first and then come back and try to make
4101          * our reservation.
4102          */
4103         if (used <= space_info->total_bytes) {
4104                 if (used + orig_bytes <= space_info->total_bytes) {
4105                         space_info->bytes_may_use += orig_bytes;
4106                         trace_btrfs_space_reservation(root->fs_info,
4107                                 "space_info", space_info->flags, orig_bytes, 1);
4108                         ret = 0;
4109                 } else {
4110                         /*
4111                          * Ok set num_bytes to orig_bytes since we aren't
4112                          * overocmmitted, this way we only try and reclaim what
4113                          * we need.
4114                          */
4115                         num_bytes = orig_bytes;
4116                 }
4117         } else {
4118                 /*
4119                  * Ok we're over committed, set num_bytes to the overcommitted
4120                  * amount plus the amount of bytes that we need for this
4121                  * reservation.
4122                  */
4123                 num_bytes = used - space_info->total_bytes +
4124                         (orig_bytes * 2);
4125         }
4126
4127         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4128                 space_info->bytes_may_use += orig_bytes;
4129                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4130                                               space_info->flags, orig_bytes,
4131                                               1);
4132                 ret = 0;
4133         }
4134
4135         /*
4136          * Couldn't make our reservation, save our place so while we're trying
4137          * to reclaim space we can actually use it instead of somebody else
4138          * stealing it from us.
4139          *
4140          * We make the other tasks wait for the flush only when we can flush
4141          * all things.
4142          */
4143         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4144                 flushing = true;
4145                 space_info->flush = 1;
4146         }
4147
4148         spin_unlock(&space_info->lock);
4149
4150         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4151                 goto out;
4152
4153         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4154                           flush_state);
4155         flush_state++;
4156
4157         /*
4158          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4159          * would happen. So skip delalloc flush.
4160          */
4161         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4162             (flush_state == FLUSH_DELALLOC ||
4163              flush_state == FLUSH_DELALLOC_WAIT))
4164                 flush_state = ALLOC_CHUNK;
4165
4166         if (!ret)
4167                 goto again;
4168         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4169                  flush_state < COMMIT_TRANS)
4170                 goto again;
4171         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4172                  flush_state <= COMMIT_TRANS)
4173                 goto again;
4174
4175 out:
4176         if (ret == -ENOSPC &&
4177             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4178                 struct btrfs_block_rsv *global_rsv =
4179                         &root->fs_info->global_block_rsv;
4180
4181                 if (block_rsv != global_rsv &&
4182                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4183                         ret = 0;
4184         }
4185         if (flushing) {
4186                 spin_lock(&space_info->lock);
4187                 space_info->flush = 0;
4188                 wake_up_all(&space_info->wait);
4189                 spin_unlock(&space_info->lock);
4190         }
4191         return ret;
4192 }
4193
4194 static struct btrfs_block_rsv *get_block_rsv(
4195                                         const struct btrfs_trans_handle *trans,
4196                                         const struct btrfs_root *root)
4197 {
4198         struct btrfs_block_rsv *block_rsv = NULL;
4199
4200         if (root->ref_cows)
4201                 block_rsv = trans->block_rsv;
4202
4203         if (root == root->fs_info->csum_root && trans->adding_csums)
4204                 block_rsv = trans->block_rsv;
4205
4206         if (!block_rsv)
4207                 block_rsv = root->block_rsv;
4208
4209         if (!block_rsv)
4210                 block_rsv = &root->fs_info->empty_block_rsv;
4211
4212         return block_rsv;
4213 }
4214
4215 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4216                                u64 num_bytes)
4217 {
4218         int ret = -ENOSPC;
4219         spin_lock(&block_rsv->lock);
4220         if (block_rsv->reserved >= num_bytes) {
4221                 block_rsv->reserved -= num_bytes;
4222                 if (block_rsv->reserved < block_rsv->size)
4223                         block_rsv->full = 0;
4224                 ret = 0;
4225         }
4226         spin_unlock(&block_rsv->lock);
4227         return ret;
4228 }
4229
4230 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4231                                 u64 num_bytes, int update_size)
4232 {
4233         spin_lock(&block_rsv->lock);
4234         block_rsv->reserved += num_bytes;
4235         if (update_size)
4236                 block_rsv->size += num_bytes;
4237         else if (block_rsv->reserved >= block_rsv->size)
4238                 block_rsv->full = 1;
4239         spin_unlock(&block_rsv->lock);
4240 }
4241
4242 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4243                                     struct btrfs_block_rsv *block_rsv,
4244                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4245 {
4246         struct btrfs_space_info *space_info = block_rsv->space_info;
4247
4248         spin_lock(&block_rsv->lock);
4249         if (num_bytes == (u64)-1)
4250                 num_bytes = block_rsv->size;
4251         block_rsv->size -= num_bytes;
4252         if (block_rsv->reserved >= block_rsv->size) {
4253                 num_bytes = block_rsv->reserved - block_rsv->size;
4254                 block_rsv->reserved = block_rsv->size;
4255                 block_rsv->full = 1;
4256         } else {
4257                 num_bytes = 0;
4258         }
4259         spin_unlock(&block_rsv->lock);
4260
4261         if (num_bytes > 0) {
4262                 if (dest) {
4263                         spin_lock(&dest->lock);
4264                         if (!dest->full) {
4265                                 u64 bytes_to_add;
4266
4267                                 bytes_to_add = dest->size - dest->reserved;
4268                                 bytes_to_add = min(num_bytes, bytes_to_add);
4269                                 dest->reserved += bytes_to_add;
4270                                 if (dest->reserved >= dest->size)
4271                                         dest->full = 1;
4272                                 num_bytes -= bytes_to_add;
4273                         }
4274                         spin_unlock(&dest->lock);
4275                 }
4276                 if (num_bytes) {
4277                         spin_lock(&space_info->lock);
4278                         space_info->bytes_may_use -= num_bytes;
4279                         trace_btrfs_space_reservation(fs_info, "space_info",
4280                                         space_info->flags, num_bytes, 0);
4281                         space_info->reservation_progress++;
4282                         spin_unlock(&space_info->lock);
4283                 }
4284         }
4285 }
4286
4287 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4288                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4289 {
4290         int ret;
4291
4292         ret = block_rsv_use_bytes(src, num_bytes);
4293         if (ret)
4294                 return ret;
4295
4296         block_rsv_add_bytes(dst, num_bytes, 1);
4297         return 0;
4298 }
4299
4300 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4301 {
4302         memset(rsv, 0, sizeof(*rsv));
4303         spin_lock_init(&rsv->lock);
4304         rsv->type = type;
4305 }
4306
4307 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4308                                               unsigned short type)
4309 {
4310         struct btrfs_block_rsv *block_rsv;
4311         struct btrfs_fs_info *fs_info = root->fs_info;
4312
4313         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4314         if (!block_rsv)
4315                 return NULL;
4316
4317         btrfs_init_block_rsv(block_rsv, type);
4318         block_rsv->space_info = __find_space_info(fs_info,
4319                                                   BTRFS_BLOCK_GROUP_METADATA);
4320         return block_rsv;
4321 }
4322
4323 void btrfs_free_block_rsv(struct btrfs_root *root,
4324                           struct btrfs_block_rsv *rsv)
4325 {
4326         if (!rsv)
4327                 return;
4328         btrfs_block_rsv_release(root, rsv, (u64)-1);
4329         kfree(rsv);
4330 }
4331
4332 int btrfs_block_rsv_add(struct btrfs_root *root,
4333                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4334                         enum btrfs_reserve_flush_enum flush)
4335 {
4336         int ret;
4337
4338         if (num_bytes == 0)
4339                 return 0;
4340
4341         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4342         if (!ret) {
4343                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4344                 return 0;
4345         }
4346
4347         return ret;
4348 }
4349
4350 int btrfs_block_rsv_check(struct btrfs_root *root,
4351                           struct btrfs_block_rsv *block_rsv, int min_factor)
4352 {
4353         u64 num_bytes = 0;
4354         int ret = -ENOSPC;
4355
4356         if (!block_rsv)
4357                 return 0;
4358
4359         spin_lock(&block_rsv->lock);
4360         num_bytes = div_factor(block_rsv->size, min_factor);
4361         if (block_rsv->reserved >= num_bytes)
4362                 ret = 0;
4363         spin_unlock(&block_rsv->lock);
4364
4365         return ret;
4366 }
4367
4368 int btrfs_block_rsv_refill(struct btrfs_root *root,
4369                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4370                            enum btrfs_reserve_flush_enum flush)
4371 {
4372         u64 num_bytes = 0;
4373         int ret = -ENOSPC;
4374
4375         if (!block_rsv)
4376                 return 0;
4377
4378         spin_lock(&block_rsv->lock);
4379         num_bytes = min_reserved;
4380         if (block_rsv->reserved >= num_bytes)
4381                 ret = 0;
4382         else
4383                 num_bytes -= block_rsv->reserved;
4384         spin_unlock(&block_rsv->lock);
4385
4386         if (!ret)
4387                 return 0;
4388
4389         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4390         if (!ret) {
4391                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4392                 return 0;
4393         }
4394
4395         return ret;
4396 }
4397
4398 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4399                             struct btrfs_block_rsv *dst_rsv,
4400                             u64 num_bytes)
4401 {
4402         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4403 }
4404
4405 void btrfs_block_rsv_release(struct btrfs_root *root,
4406                              struct btrfs_block_rsv *block_rsv,
4407                              u64 num_bytes)
4408 {
4409         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4410         if (global_rsv->full || global_rsv == block_rsv ||
4411             block_rsv->space_info != global_rsv->space_info)
4412                 global_rsv = NULL;
4413         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4414                                 num_bytes);
4415 }
4416
4417 /*
4418  * helper to calculate size of global block reservation.
4419  * the desired value is sum of space used by extent tree,
4420  * checksum tree and root tree
4421  */
4422 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4423 {
4424         struct btrfs_space_info *sinfo;
4425         u64 num_bytes;
4426         u64 meta_used;
4427         u64 data_used;
4428         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4429
4430         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4431         spin_lock(&sinfo->lock);
4432         data_used = sinfo->bytes_used;
4433         spin_unlock(&sinfo->lock);
4434
4435         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4436         spin_lock(&sinfo->lock);
4437         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4438                 data_used = 0;
4439         meta_used = sinfo->bytes_used;
4440         spin_unlock(&sinfo->lock);
4441
4442         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4443                     csum_size * 2;
4444         num_bytes += div64_u64(data_used + meta_used, 50);
4445
4446         if (num_bytes * 3 > meta_used)
4447                 num_bytes = div64_u64(meta_used, 3);
4448
4449         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4450 }
4451
4452 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4453 {
4454         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4455         struct btrfs_space_info *sinfo = block_rsv->space_info;
4456         u64 num_bytes;
4457
4458         num_bytes = calc_global_metadata_size(fs_info);
4459
4460         spin_lock(&sinfo->lock);
4461         spin_lock(&block_rsv->lock);
4462
4463         block_rsv->size = num_bytes;
4464
4465         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4466                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4467                     sinfo->bytes_may_use;
4468
4469         if (sinfo->total_bytes > num_bytes) {
4470                 num_bytes = sinfo->total_bytes - num_bytes;
4471                 block_rsv->reserved += num_bytes;
4472                 sinfo->bytes_may_use += num_bytes;
4473                 trace_btrfs_space_reservation(fs_info, "space_info",
4474                                       sinfo->flags, num_bytes, 1);
4475         }
4476
4477         if (block_rsv->reserved >= block_rsv->size) {
4478                 num_bytes = block_rsv->reserved - block_rsv->size;
4479                 sinfo->bytes_may_use -= num_bytes;
4480                 trace_btrfs_space_reservation(fs_info, "space_info",
4481                                       sinfo->flags, num_bytes, 0);
4482                 sinfo->reservation_progress++;
4483                 block_rsv->reserved = block_rsv->size;
4484                 block_rsv->full = 1;
4485         }
4486
4487         spin_unlock(&block_rsv->lock);
4488         spin_unlock(&sinfo->lock);
4489 }
4490
4491 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4492 {
4493         struct btrfs_space_info *space_info;
4494
4495         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4496         fs_info->chunk_block_rsv.space_info = space_info;
4497
4498         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4499         fs_info->global_block_rsv.space_info = space_info;
4500         fs_info->delalloc_block_rsv.space_info = space_info;
4501         fs_info->trans_block_rsv.space_info = space_info;
4502         fs_info->empty_block_rsv.space_info = space_info;
4503         fs_info->delayed_block_rsv.space_info = space_info;
4504
4505         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4506         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4507         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4508         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4509         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4510
4511         update_global_block_rsv(fs_info);
4512 }
4513
4514 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4515 {
4516         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4517                                 (u64)-1);
4518         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4519         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4520         WARN_ON(fs_info->trans_block_rsv.size > 0);
4521         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4522         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4523         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4524         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4525         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4526 }
4527
4528 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4529                                   struct btrfs_root *root)
4530 {
4531         if (!trans->block_rsv)
4532                 return;
4533
4534         if (!trans->bytes_reserved)
4535                 return;
4536
4537         trace_btrfs_space_reservation(root->fs_info, "transaction",
4538                                       trans->transid, trans->bytes_reserved, 0);
4539         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4540         trans->bytes_reserved = 0;
4541 }
4542
4543 /* Can only return 0 or -ENOSPC */
4544 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4545                                   struct inode *inode)
4546 {
4547         struct btrfs_root *root = BTRFS_I(inode)->root;
4548         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4549         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4550
4551         /*
4552          * We need to hold space in order to delete our orphan item once we've
4553          * added it, so this takes the reservation so we can release it later
4554          * when we are truly done with the orphan item.
4555          */
4556         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4557         trace_btrfs_space_reservation(root->fs_info, "orphan",
4558                                       btrfs_ino(inode), num_bytes, 1);
4559         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4560 }
4561
4562 void btrfs_orphan_release_metadata(struct inode *inode)
4563 {
4564         struct btrfs_root *root = BTRFS_I(inode)->root;
4565         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4566         trace_btrfs_space_reservation(root->fs_info, "orphan",
4567                                       btrfs_ino(inode), num_bytes, 0);
4568         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4569 }
4570
4571 /*
4572  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4573  * root: the root of the parent directory
4574  * rsv: block reservation
4575  * items: the number of items that we need do reservation
4576  * qgroup_reserved: used to return the reserved size in qgroup
4577  *
4578  * This function is used to reserve the space for snapshot/subvolume
4579  * creation and deletion. Those operations are different with the
4580  * common file/directory operations, they change two fs/file trees
4581  * and root tree, the number of items that the qgroup reserves is
4582  * different with the free space reservation. So we can not use
4583  * the space reseravtion mechanism in start_transaction().
4584  */
4585 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4586                                      struct btrfs_block_rsv *rsv,
4587                                      int items,
4588                                      u64 *qgroup_reserved)
4589 {
4590         u64 num_bytes;
4591         int ret;
4592
4593         if (root->fs_info->quota_enabled) {
4594                 /* One for parent inode, two for dir entries */
4595                 num_bytes = 3 * root->leafsize;
4596                 ret = btrfs_qgroup_reserve(root, num_bytes);
4597                 if (ret)
4598                         return ret;
4599         } else {
4600                 num_bytes = 0;
4601         }
4602
4603         *qgroup_reserved = num_bytes;
4604
4605         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4606         rsv->space_info = __find_space_info(root->fs_info,
4607                                             BTRFS_BLOCK_GROUP_METADATA);
4608         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4609                                   BTRFS_RESERVE_FLUSH_ALL);
4610         if (ret) {
4611                 if (*qgroup_reserved)
4612                         btrfs_qgroup_free(root, *qgroup_reserved);
4613         }
4614
4615         return ret;
4616 }
4617
4618 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4619                                       struct btrfs_block_rsv *rsv,
4620                                       u64 qgroup_reserved)
4621 {
4622         btrfs_block_rsv_release(root, rsv, (u64)-1);
4623         if (qgroup_reserved)
4624                 btrfs_qgroup_free(root, qgroup_reserved);
4625 }
4626
4627 /**
4628  * drop_outstanding_extent - drop an outstanding extent
4629  * @inode: the inode we're dropping the extent for
4630  *
4631  * This is called when we are freeing up an outstanding extent, either called
4632  * after an error or after an extent is written.  This will return the number of
4633  * reserved extents that need to be freed.  This must be called with
4634  * BTRFS_I(inode)->lock held.
4635  */
4636 static unsigned drop_outstanding_extent(struct inode *inode)
4637 {
4638         unsigned drop_inode_space = 0;
4639         unsigned dropped_extents = 0;
4640
4641         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4642         BTRFS_I(inode)->outstanding_extents--;
4643
4644         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4645             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4646                                &BTRFS_I(inode)->runtime_flags))
4647                 drop_inode_space = 1;
4648
4649         /*
4650          * If we have more or the same amount of outsanding extents than we have
4651          * reserved then we need to leave the reserved extents count alone.
4652          */
4653         if (BTRFS_I(inode)->outstanding_extents >=
4654             BTRFS_I(inode)->reserved_extents)
4655                 return drop_inode_space;
4656
4657         dropped_extents = BTRFS_I(inode)->reserved_extents -
4658                 BTRFS_I(inode)->outstanding_extents;
4659         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4660         return dropped_extents + drop_inode_space;
4661 }
4662
4663 /**
4664  * calc_csum_metadata_size - return the amount of metada space that must be
4665  *      reserved/free'd for the given bytes.
4666  * @inode: the inode we're manipulating
4667  * @num_bytes: the number of bytes in question
4668  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4669  *
4670  * This adjusts the number of csum_bytes in the inode and then returns the
4671  * correct amount of metadata that must either be reserved or freed.  We
4672  * calculate how many checksums we can fit into one leaf and then divide the
4673  * number of bytes that will need to be checksumed by this value to figure out
4674  * how many checksums will be required.  If we are adding bytes then the number
4675  * may go up and we will return the number of additional bytes that must be
4676  * reserved.  If it is going down we will return the number of bytes that must
4677  * be freed.
4678  *
4679  * This must be called with BTRFS_I(inode)->lock held.
4680  */
4681 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4682                                    int reserve)
4683 {
4684         struct btrfs_root *root = BTRFS_I(inode)->root;
4685         u64 csum_size;
4686         int num_csums_per_leaf;
4687         int num_csums;
4688         int old_csums;
4689
4690         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4691             BTRFS_I(inode)->csum_bytes == 0)
4692                 return 0;
4693
4694         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4695         if (reserve)
4696                 BTRFS_I(inode)->csum_bytes += num_bytes;
4697         else
4698                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4699         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4700         num_csums_per_leaf = (int)div64_u64(csum_size,
4701                                             sizeof(struct btrfs_csum_item) +
4702                                             sizeof(struct btrfs_disk_key));
4703         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4704         num_csums = num_csums + num_csums_per_leaf - 1;
4705         num_csums = num_csums / num_csums_per_leaf;
4706
4707         old_csums = old_csums + num_csums_per_leaf - 1;
4708         old_csums = old_csums / num_csums_per_leaf;
4709
4710         /* No change, no need to reserve more */
4711         if (old_csums == num_csums)
4712                 return 0;
4713
4714         if (reserve)
4715                 return btrfs_calc_trans_metadata_size(root,
4716                                                       num_csums - old_csums);
4717
4718         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4719 }
4720
4721 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4722 {
4723         struct btrfs_root *root = BTRFS_I(inode)->root;
4724         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4725         u64 to_reserve = 0;
4726         u64 csum_bytes;
4727         unsigned nr_extents = 0;
4728         int extra_reserve = 0;
4729         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
4730         int ret = 0;
4731         bool delalloc_lock = true;
4732         u64 to_free = 0;
4733         unsigned dropped;
4734
4735         /* If we are a free space inode we need to not flush since we will be in
4736          * the middle of a transaction commit.  We also don't need the delalloc
4737          * mutex since we won't race with anybody.  We need this mostly to make
4738          * lockdep shut its filthy mouth.
4739          */
4740         if (btrfs_is_free_space_inode(inode)) {
4741                 flush = BTRFS_RESERVE_NO_FLUSH;
4742                 delalloc_lock = false;
4743         }
4744
4745         if (flush != BTRFS_RESERVE_NO_FLUSH &&
4746             btrfs_transaction_in_commit(root->fs_info))
4747                 schedule_timeout(1);
4748
4749         if (delalloc_lock)
4750                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4751
4752         num_bytes = ALIGN(num_bytes, root->sectorsize);
4753
4754         spin_lock(&BTRFS_I(inode)->lock);
4755         BTRFS_I(inode)->outstanding_extents++;
4756
4757         if (BTRFS_I(inode)->outstanding_extents >
4758             BTRFS_I(inode)->reserved_extents)
4759                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4760                         BTRFS_I(inode)->reserved_extents;
4761
4762         /*
4763          * Add an item to reserve for updating the inode when we complete the
4764          * delalloc io.
4765          */
4766         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4767                       &BTRFS_I(inode)->runtime_flags)) {
4768                 nr_extents++;
4769                 extra_reserve = 1;
4770         }
4771
4772         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4773         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4774         csum_bytes = BTRFS_I(inode)->csum_bytes;
4775         spin_unlock(&BTRFS_I(inode)->lock);
4776
4777         if (root->fs_info->quota_enabled) {
4778                 ret = btrfs_qgroup_reserve(root, num_bytes +
4779                                            nr_extents * root->leafsize);
4780                 if (ret)
4781                         goto out_fail;
4782         }
4783
4784         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4785         if (unlikely(ret)) {
4786                 if (root->fs_info->quota_enabled)
4787                         btrfs_qgroup_free(root, num_bytes +
4788                                                 nr_extents * root->leafsize);
4789                 goto out_fail;
4790         }
4791
4792         spin_lock(&BTRFS_I(inode)->lock);
4793         if (extra_reserve) {
4794                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4795                         &BTRFS_I(inode)->runtime_flags);
4796                 nr_extents--;
4797         }
4798         BTRFS_I(inode)->reserved_extents += nr_extents;
4799         spin_unlock(&BTRFS_I(inode)->lock);
4800
4801         if (delalloc_lock)
4802                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4803
4804         if (to_reserve)
4805                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4806                                               btrfs_ino(inode), to_reserve, 1);
4807         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4808
4809         return 0;
4810
4811 out_fail:
4812         spin_lock(&BTRFS_I(inode)->lock);
4813         dropped = drop_outstanding_extent(inode);
4814         /*
4815          * If the inodes csum_bytes is the same as the original
4816          * csum_bytes then we know we haven't raced with any free()ers
4817          * so we can just reduce our inodes csum bytes and carry on.
4818          * Otherwise we have to do the normal free thing to account for
4819          * the case that the free side didn't free up its reserve
4820          * because of this outstanding reservation.
4821          */
4822         if (BTRFS_I(inode)->csum_bytes == csum_bytes)
4823                 calc_csum_metadata_size(inode, num_bytes, 0);
4824         else
4825                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4826         spin_unlock(&BTRFS_I(inode)->lock);
4827         if (dropped)
4828                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4829
4830         if (to_free) {
4831                 btrfs_block_rsv_release(root, block_rsv, to_free);
4832                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
4833                                               btrfs_ino(inode), to_free, 0);
4834         }
4835         if (delalloc_lock)
4836                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4837         return ret;
4838 }
4839
4840 /**
4841  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4842  * @inode: the inode to release the reservation for
4843  * @num_bytes: the number of bytes we're releasing
4844  *
4845  * This will release the metadata reservation for an inode.  This can be called
4846  * once we complete IO for a given set of bytes to release their metadata
4847  * reservations.
4848  */
4849 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4850 {
4851         struct btrfs_root *root = BTRFS_I(inode)->root;
4852         u64 to_free = 0;
4853         unsigned dropped;
4854
4855         num_bytes = ALIGN(num_bytes, root->sectorsize);
4856         spin_lock(&BTRFS_I(inode)->lock);
4857         dropped = drop_outstanding_extent(inode);
4858
4859         if (num_bytes)
4860                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4861         spin_unlock(&BTRFS_I(inode)->lock);
4862         if (dropped > 0)
4863                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4864
4865         trace_btrfs_space_reservation(root->fs_info, "delalloc",
4866                                       btrfs_ino(inode), to_free, 0);
4867         if (root->fs_info->quota_enabled) {
4868                 btrfs_qgroup_free(root, num_bytes +
4869                                         dropped * root->leafsize);
4870         }
4871
4872         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4873                                 to_free);
4874 }
4875
4876 /**
4877  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4878  * @inode: inode we're writing to
4879  * @num_bytes: the number of bytes we want to allocate
4880  *
4881  * This will do the following things
4882  *
4883  * o reserve space in the data space info for num_bytes
4884  * o reserve space in the metadata space info based on number of outstanding
4885  *   extents and how much csums will be needed
4886  * o add to the inodes ->delalloc_bytes
4887  * o add it to the fs_info's delalloc inodes list.
4888  *
4889  * This will return 0 for success and -ENOSPC if there is no space left.
4890  */
4891 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4892 {
4893         int ret;
4894
4895         ret = btrfs_check_data_free_space(inode, num_bytes);
4896         if (ret)
4897                 return ret;
4898
4899         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4900         if (ret) {
4901                 btrfs_free_reserved_data_space(inode, num_bytes);
4902                 return ret;
4903         }
4904
4905         return 0;
4906 }
4907
4908 /**
4909  * btrfs_delalloc_release_space - release data and metadata space for delalloc
4910  * @inode: inode we're releasing space for
4911  * @num_bytes: the number of bytes we want to free up
4912  *
4913  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
4914  * called in the case that we don't need the metadata AND data reservations
4915  * anymore.  So if there is an error or we insert an inline extent.
4916  *
4917  * This function will release the metadata space that was not used and will
4918  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
4919  * list if there are no delalloc bytes left.
4920  */
4921 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4922 {
4923         btrfs_delalloc_release_metadata(inode, num_bytes);
4924         btrfs_free_reserved_data_space(inode, num_bytes);
4925 }
4926
4927 static int update_block_group(struct btrfs_root *root,
4928                               u64 bytenr, u64 num_bytes, int alloc)
4929 {
4930         struct btrfs_block_group_cache *cache = NULL;
4931         struct btrfs_fs_info *info = root->fs_info;
4932         u64 total = num_bytes;
4933         u64 old_val;
4934         u64 byte_in_group;
4935         int factor;
4936
4937         /* block accounting for super block */
4938         spin_lock(&info->delalloc_lock);
4939         old_val = btrfs_super_bytes_used(info->super_copy);
4940         if (alloc)
4941                 old_val += num_bytes;
4942         else
4943                 old_val -= num_bytes;
4944         btrfs_set_super_bytes_used(info->super_copy, old_val);
4945         spin_unlock(&info->delalloc_lock);
4946
4947         while (total) {
4948                 cache = btrfs_lookup_block_group(info, bytenr);
4949                 if (!cache)
4950                         return -ENOENT;
4951                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4952                                     BTRFS_BLOCK_GROUP_RAID1 |
4953                                     BTRFS_BLOCK_GROUP_RAID10))
4954                         factor = 2;
4955                 else
4956                         factor = 1;
4957                 /*
4958                  * If this block group has free space cache written out, we
4959                  * need to make sure to load it if we are removing space.  This
4960                  * is because we need the unpinning stage to actually add the
4961                  * space back to the block group, otherwise we will leak space.
4962                  */
4963                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4964                         cache_block_group(cache, 1);
4965
4966                 byte_in_group = bytenr - cache->key.objectid;
4967                 WARN_ON(byte_in_group > cache->key.offset);
4968
4969                 spin_lock(&cache->space_info->lock);
4970                 spin_lock(&cache->lock);
4971
4972                 if (btrfs_test_opt(root, SPACE_CACHE) &&
4973                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4974                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4975
4976                 cache->dirty = 1;
4977                 old_val = btrfs_block_group_used(&cache->item);
4978                 num_bytes = min(total, cache->key.offset - byte_in_group);
4979                 if (alloc) {
4980                         old_val += num_bytes;
4981                         btrfs_set_block_group_used(&cache->item, old_val);
4982                         cache->reserved -= num_bytes;
4983                         cache->space_info->bytes_reserved -= num_bytes;
4984                         cache->space_info->bytes_used += num_bytes;
4985                         cache->space_info->disk_used += num_bytes * factor;
4986                         spin_unlock(&cache->lock);
4987                         spin_unlock(&cache->space_info->lock);
4988                 } else {
4989                         old_val -= num_bytes;
4990                         btrfs_set_block_group_used(&cache->item, old_val);
4991                         cache->pinned += num_bytes;
4992                         cache->space_info->bytes_pinned += num_bytes;
4993                         cache->space_info->bytes_used -= num_bytes;
4994                         cache->space_info->disk_used -= num_bytes * factor;
4995                         spin_unlock(&cache->lock);
4996                         spin_unlock(&cache->space_info->lock);
4997
4998                         set_extent_dirty(info->pinned_extents,
4999                                          bytenr, bytenr + num_bytes - 1,
5000                                          GFP_NOFS | __GFP_NOFAIL);
5001                 }
5002                 btrfs_put_block_group(cache);
5003                 total -= num_bytes;
5004                 bytenr += num_bytes;
5005         }
5006         return 0;
5007 }
5008
5009 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5010 {
5011         struct btrfs_block_group_cache *cache;
5012         u64 bytenr;
5013
5014         spin_lock(&root->fs_info->block_group_cache_lock);
5015         bytenr = root->fs_info->first_logical_byte;
5016         spin_unlock(&root->fs_info->block_group_cache_lock);
5017
5018         if (bytenr < (u64)-1)
5019                 return bytenr;
5020
5021         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5022         if (!cache)
5023                 return 0;
5024
5025         bytenr = cache->key.objectid;
5026         btrfs_put_block_group(cache);
5027
5028         return bytenr;
5029 }
5030
5031 static int pin_down_extent(struct btrfs_root *root,
5032                            struct btrfs_block_group_cache *cache,
5033                            u64 bytenr, u64 num_bytes, int reserved)
5034 {
5035         spin_lock(&cache->space_info->lock);
5036         spin_lock(&cache->lock);
5037         cache->pinned += num_bytes;
5038         cache->space_info->bytes_pinned += num_bytes;
5039         if (reserved) {
5040                 cache->reserved -= num_bytes;
5041                 cache->space_info->bytes_reserved -= num_bytes;
5042         }
5043         spin_unlock(&cache->lock);
5044         spin_unlock(&cache->space_info->lock);
5045
5046         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5047                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5048         return 0;
5049 }
5050
5051 /*
5052  * this function must be called within transaction
5053  */
5054 int btrfs_pin_extent(struct btrfs_root *root,
5055                      u64 bytenr, u64 num_bytes, int reserved)
5056 {
5057         struct btrfs_block_group_cache *cache;
5058
5059         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5060         BUG_ON(!cache); /* Logic error */
5061
5062         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5063
5064         btrfs_put_block_group(cache);
5065         return 0;
5066 }
5067
5068 /*
5069  * this function must be called within transaction
5070  */
5071 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5072                                     u64 bytenr, u64 num_bytes)
5073 {
5074         struct btrfs_block_group_cache *cache;
5075
5076         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5077         BUG_ON(!cache); /* Logic error */
5078
5079         /*
5080          * pull in the free space cache (if any) so that our pin
5081          * removes the free space from the cache.  We have load_only set
5082          * to one because the slow code to read in the free extents does check
5083          * the pinned extents.
5084          */
5085         cache_block_group(cache, 1);
5086
5087         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5088
5089         /* remove us from the free space cache (if we're there at all) */
5090         btrfs_remove_free_space(cache, bytenr, num_bytes);
5091         btrfs_put_block_group(cache);
5092         return 0;
5093 }
5094
5095 /**
5096  * btrfs_update_reserved_bytes - update the block_group and space info counters
5097  * @cache:      The cache we are manipulating
5098  * @num_bytes:  The number of bytes in question
5099  * @reserve:    One of the reservation enums
5100  *
5101  * This is called by the allocator when it reserves space, or by somebody who is
5102  * freeing space that was never actually used on disk.  For example if you
5103  * reserve some space for a new leaf in transaction A and before transaction A
5104  * commits you free that leaf, you call this with reserve set to 0 in order to
5105  * clear the reservation.
5106  *
5107  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5108  * ENOSPC accounting.  For data we handle the reservation through clearing the
5109  * delalloc bits in the io_tree.  We have to do this since we could end up
5110  * allocating less disk space for the amount of data we have reserved in the
5111  * case of compression.
5112  *
5113  * If this is a reservation and the block group has become read only we cannot
5114  * make the reservation and return -EAGAIN, otherwise this function always
5115  * succeeds.
5116  */
5117 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5118                                        u64 num_bytes, int reserve)
5119 {
5120         struct btrfs_space_info *space_info = cache->space_info;
5121         int ret = 0;
5122
5123         spin_lock(&space_info->lock);
5124         spin_lock(&cache->lock);
5125         if (reserve != RESERVE_FREE) {
5126                 if (cache->ro) {
5127                         ret = -EAGAIN;
5128                 } else {
5129                         cache->reserved += num_bytes;
5130                         space_info->bytes_reserved += num_bytes;
5131                         if (reserve == RESERVE_ALLOC) {
5132                                 trace_btrfs_space_reservation(cache->fs_info,
5133                                                 "space_info", space_info->flags,
5134                                                 num_bytes, 0);
5135                                 space_info->bytes_may_use -= num_bytes;
5136                         }
5137                 }
5138         } else {
5139                 if (cache->ro)
5140                         space_info->bytes_readonly += num_bytes;
5141                 cache->reserved -= num_bytes;
5142                 space_info->bytes_reserved -= num_bytes;
5143                 space_info->reservation_progress++;
5144         }
5145         spin_unlock(&cache->lock);
5146         spin_unlock(&space_info->lock);
5147         return ret;
5148 }
5149
5150 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5151                                 struct btrfs_root *root)
5152 {
5153         struct btrfs_fs_info *fs_info = root->fs_info;
5154         struct btrfs_caching_control *next;
5155         struct btrfs_caching_control *caching_ctl;
5156         struct btrfs_block_group_cache *cache;
5157
5158         down_write(&fs_info->extent_commit_sem);
5159
5160         list_for_each_entry_safe(caching_ctl, next,
5161                                  &fs_info->caching_block_groups, list) {
5162                 cache = caching_ctl->block_group;
5163                 if (block_group_cache_done(cache)) {
5164                         cache->last_byte_to_unpin = (u64)-1;
5165                         list_del_init(&caching_ctl->list);
5166                         put_caching_control(caching_ctl);
5167                 } else {
5168                         cache->last_byte_to_unpin = caching_ctl->progress;
5169                 }
5170         }
5171
5172         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5173                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5174         else
5175                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5176
5177         up_write(&fs_info->extent_commit_sem);
5178
5179         update_global_block_rsv(fs_info);
5180 }
5181
5182 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5183 {
5184         struct btrfs_fs_info *fs_info = root->fs_info;
5185         struct btrfs_block_group_cache *cache = NULL;
5186         struct btrfs_space_info *space_info;
5187         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5188         u64 len;
5189         bool readonly;
5190
5191         while (start <= end) {
5192                 readonly = false;
5193                 if (!cache ||
5194                     start >= cache->key.objectid + cache->key.offset) {
5195                         if (cache)
5196                                 btrfs_put_block_group(cache);
5197                         cache = btrfs_lookup_block_group(fs_info, start);
5198                         BUG_ON(!cache); /* Logic error */
5199                 }
5200
5201                 len = cache->key.objectid + cache->key.offset - start;
5202                 len = min(len, end + 1 - start);
5203
5204                 if (start < cache->last_byte_to_unpin) {
5205                         len = min(len, cache->last_byte_to_unpin - start);
5206                         btrfs_add_free_space(cache, start, len);
5207                 }
5208
5209                 start += len;
5210                 space_info = cache->space_info;
5211
5212                 spin_lock(&space_info->lock);
5213                 spin_lock(&cache->lock);
5214                 cache->pinned -= len;
5215                 space_info->bytes_pinned -= len;
5216                 if (cache->ro) {
5217                         space_info->bytes_readonly += len;
5218                         readonly = true;
5219                 }
5220                 spin_unlock(&cache->lock);
5221                 if (!readonly && global_rsv->space_info == space_info) {
5222                         spin_lock(&global_rsv->lock);
5223                         if (!global_rsv->full) {
5224                                 len = min(len, global_rsv->size -
5225                                           global_rsv->reserved);
5226                                 global_rsv->reserved += len;
5227                                 space_info->bytes_may_use += len;
5228                                 if (global_rsv->reserved >= global_rsv->size)
5229                                         global_rsv->full = 1;
5230                         }
5231                         spin_unlock(&global_rsv->lock);
5232                 }
5233                 spin_unlock(&space_info->lock);
5234         }
5235
5236         if (cache)
5237                 btrfs_put_block_group(cache);
5238         return 0;
5239 }
5240
5241 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5242                                struct btrfs_root *root)
5243 {
5244         struct btrfs_fs_info *fs_info = root->fs_info;
5245         struct extent_io_tree *unpin;
5246         u64 start;
5247         u64 end;
5248         int ret;
5249
5250         if (trans->aborted)
5251                 return 0;
5252
5253         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5254                 unpin = &fs_info->freed_extents[1];
5255         else
5256                 unpin = &fs_info->freed_extents[0];
5257
5258         while (1) {
5259                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5260                                             EXTENT_DIRTY, NULL);
5261                 if (ret)
5262                         break;
5263
5264                 if (btrfs_test_opt(root, DISCARD))
5265                         ret = btrfs_discard_extent(root, start,
5266                                                    end + 1 - start, NULL);
5267
5268                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5269                 unpin_extent_range(root, start, end);
5270                 cond_resched();
5271         }
5272
5273         return 0;
5274 }
5275
5276 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5277                                 struct btrfs_root *root,
5278                                 u64 bytenr, u64 num_bytes, u64 parent,
5279                                 u64 root_objectid, u64 owner_objectid,
5280                                 u64 owner_offset, int refs_to_drop,
5281                                 struct btrfs_delayed_extent_op *extent_op)
5282 {
5283         struct btrfs_key key;
5284         struct btrfs_path *path;
5285         struct btrfs_fs_info *info = root->fs_info;
5286         struct btrfs_root *extent_root = info->extent_root;
5287         struct extent_buffer *leaf;
5288         struct btrfs_extent_item *ei;
5289         struct btrfs_extent_inline_ref *iref;
5290         int ret;
5291         int is_data;
5292         int extent_slot = 0;
5293         int found_extent = 0;
5294         int num_to_del = 1;
5295         u32 item_size;
5296         u64 refs;
5297
5298         path = btrfs_alloc_path();
5299         if (!path)
5300                 return -ENOMEM;
5301
5302         path->reada = 1;
5303         path->leave_spinning = 1;
5304
5305         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5306         BUG_ON(!is_data && refs_to_drop != 1);
5307
5308         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5309                                     bytenr, num_bytes, parent,
5310                                     root_objectid, owner_objectid,
5311                                     owner_offset);
5312         if (ret == 0) {
5313                 extent_slot = path->slots[0];
5314                 while (extent_slot >= 0) {
5315                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5316                                               extent_slot);
5317                         if (key.objectid != bytenr)
5318                                 break;
5319                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5320                             key.offset == num_bytes) {
5321                                 found_extent = 1;
5322                                 break;
5323                         }
5324                         if (path->slots[0] - extent_slot > 5)
5325                                 break;
5326                         extent_slot--;
5327                 }
5328 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5329                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5330                 if (found_extent && item_size < sizeof(*ei))
5331                         found_extent = 0;
5332 #endif
5333                 if (!found_extent) {
5334                         BUG_ON(iref);
5335                         ret = remove_extent_backref(trans, extent_root, path,
5336                                                     NULL, refs_to_drop,
5337                                                     is_data);
5338                         if (ret) {
5339                                 btrfs_abort_transaction(trans, extent_root, ret);
5340                                 goto out;
5341                         }
5342                         btrfs_release_path(path);
5343                         path->leave_spinning = 1;
5344
5345                         key.objectid = bytenr;
5346                         key.type = BTRFS_EXTENT_ITEM_KEY;
5347                         key.offset = num_bytes;
5348
5349                         ret = btrfs_search_slot(trans, extent_root,
5350                                                 &key, path, -1, 1);
5351                         if (ret) {
5352                                 printk(KERN_ERR "umm, got %d back from search"
5353                                        ", was looking for %llu\n", ret,
5354                                        (unsigned long long)bytenr);
5355                                 if (ret > 0)
5356                                         btrfs_print_leaf(extent_root,
5357                                                          path->nodes[0]);
5358                         }
5359                         if (ret < 0) {
5360                                 btrfs_abort_transaction(trans, extent_root, ret);
5361                                 goto out;
5362                         }
5363                         extent_slot = path->slots[0];
5364                 }
5365         } else if (ret == -ENOENT) {
5366                 btrfs_print_leaf(extent_root, path->nodes[0]);
5367                 WARN_ON(1);
5368                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
5369                        "parent %llu root %llu  owner %llu offset %llu\n",
5370                        (unsigned long long)bytenr,
5371                        (unsigned long long)parent,
5372                        (unsigned long long)root_objectid,
5373                        (unsigned long long)owner_objectid,
5374                        (unsigned long long)owner_offset);
5375         } else {
5376                 btrfs_abort_transaction(trans, extent_root, ret);
5377                 goto out;
5378         }
5379
5380         leaf = path->nodes[0];
5381         item_size = btrfs_item_size_nr(leaf, extent_slot);
5382 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5383         if (item_size < sizeof(*ei)) {
5384                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5385                 ret = convert_extent_item_v0(trans, extent_root, path,
5386                                              owner_objectid, 0);
5387                 if (ret < 0) {
5388                         btrfs_abort_transaction(trans, extent_root, ret);
5389                         goto out;
5390                 }
5391
5392                 btrfs_release_path(path);
5393                 path->leave_spinning = 1;
5394
5395                 key.objectid = bytenr;
5396                 key.type = BTRFS_EXTENT_ITEM_KEY;
5397                 key.offset = num_bytes;
5398
5399                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5400                                         -1, 1);
5401                 if (ret) {
5402                         printk(KERN_ERR "umm, got %d back from search"
5403                                ", was looking for %llu\n", ret,
5404                                (unsigned long long)bytenr);
5405                         btrfs_print_leaf(extent_root, path->nodes[0]);
5406                 }
5407                 if (ret < 0) {
5408                         btrfs_abort_transaction(trans, extent_root, ret);
5409                         goto out;
5410                 }
5411
5412                 extent_slot = path->slots[0];
5413                 leaf = path->nodes[0];
5414                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5415         }
5416 #endif
5417         BUG_ON(item_size < sizeof(*ei));
5418         ei = btrfs_item_ptr(leaf, extent_slot,
5419                             struct btrfs_extent_item);
5420         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
5421                 struct btrfs_tree_block_info *bi;
5422                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5423                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5424                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5425         }
5426
5427         refs = btrfs_extent_refs(leaf, ei);
5428         BUG_ON(refs < refs_to_drop);
5429         refs -= refs_to_drop;
5430
5431         if (refs > 0) {
5432                 if (extent_op)
5433                         __run_delayed_extent_op(extent_op, leaf, ei);
5434                 /*
5435                  * In the case of inline back ref, reference count will
5436                  * be updated by remove_extent_backref
5437                  */
5438                 if (iref) {
5439                         BUG_ON(!found_extent);
5440                 } else {
5441                         btrfs_set_extent_refs(leaf, ei, refs);
5442                         btrfs_mark_buffer_dirty(leaf);
5443                 }
5444                 if (found_extent) {
5445                         ret = remove_extent_backref(trans, extent_root, path,
5446                                                     iref, refs_to_drop,
5447                                                     is_data);
5448                         if (ret) {
5449                                 btrfs_abort_transaction(trans, extent_root, ret);
5450                                 goto out;
5451                         }
5452                 }
5453         } else {
5454                 if (found_extent) {
5455                         BUG_ON(is_data && refs_to_drop !=
5456                                extent_data_ref_count(root, path, iref));
5457                         if (iref) {
5458                                 BUG_ON(path->slots[0] != extent_slot);
5459                         } else {
5460                                 BUG_ON(path->slots[0] != extent_slot + 1);
5461                                 path->slots[0] = extent_slot;
5462                                 num_to_del = 2;
5463                         }
5464                 }
5465
5466                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5467                                       num_to_del);
5468                 if (ret) {
5469                         btrfs_abort_transaction(trans, extent_root, ret);
5470                         goto out;
5471                 }
5472                 btrfs_release_path(path);
5473
5474                 if (is_data) {
5475                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5476                         if (ret) {
5477                                 btrfs_abort_transaction(trans, extent_root, ret);
5478                                 goto out;
5479                         }
5480                 }
5481
5482                 ret = update_block_group(root, bytenr, num_bytes, 0);
5483                 if (ret) {
5484                         btrfs_abort_transaction(trans, extent_root, ret);
5485                         goto out;
5486                 }
5487         }
5488 out:
5489         btrfs_free_path(path);
5490         return ret;
5491 }
5492
5493 /*
5494  * when we free an block, it is possible (and likely) that we free the last
5495  * delayed ref for that extent as well.  This searches the delayed ref tree for
5496  * a given extent, and if there are no other delayed refs to be processed, it
5497  * removes it from the tree.
5498  */
5499 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5500                                       struct btrfs_root *root, u64 bytenr)
5501 {
5502         struct btrfs_delayed_ref_head *head;
5503         struct btrfs_delayed_ref_root *delayed_refs;
5504         struct btrfs_delayed_ref_node *ref;
5505         struct rb_node *node;
5506         int ret = 0;
5507
5508         delayed_refs = &trans->transaction->delayed_refs;
5509         spin_lock(&delayed_refs->lock);
5510         head = btrfs_find_delayed_ref_head(trans, bytenr);
5511         if (!head)
5512                 goto out;
5513
5514         node = rb_prev(&head->node.rb_node);
5515         if (!node)
5516                 goto out;
5517
5518         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5519
5520         /* there are still entries for this ref, we can't drop it */
5521         if (ref->bytenr == bytenr)
5522                 goto out;
5523
5524         if (head->extent_op) {
5525                 if (!head->must_insert_reserved)
5526                         goto out;
5527                 btrfs_free_delayed_extent_op(head->extent_op);
5528                 head->extent_op = NULL;
5529         }
5530
5531         /*
5532          * waiting for the lock here would deadlock.  If someone else has it
5533          * locked they are already in the process of dropping it anyway
5534          */
5535         if (!mutex_trylock(&head->mutex))
5536                 goto out;
5537
5538         /*
5539          * at this point we have a head with no other entries.  Go
5540          * ahead and process it.
5541          */
5542         head->node.in_tree = 0;
5543         rb_erase(&head->node.rb_node, &delayed_refs->root);
5544
5545         delayed_refs->num_entries--;
5546
5547         /*
5548          * we don't take a ref on the node because we're removing it from the
5549          * tree, so we just steal the ref the tree was holding.
5550          */
5551         delayed_refs->num_heads--;
5552         if (list_empty(&head->cluster))
5553                 delayed_refs->num_heads_ready--;
5554
5555         list_del_init(&head->cluster);
5556         spin_unlock(&delayed_refs->lock);
5557
5558         BUG_ON(head->extent_op);
5559         if (head->must_insert_reserved)
5560                 ret = 1;
5561
5562         mutex_unlock(&head->mutex);
5563         btrfs_put_delayed_ref(&head->node);
5564         return ret;
5565 out:
5566         spin_unlock(&delayed_refs->lock);
5567         return 0;
5568 }
5569
5570 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5571                            struct btrfs_root *root,
5572                            struct extent_buffer *buf,
5573                            u64 parent, int last_ref)
5574 {
5575         struct btrfs_block_group_cache *cache = NULL;
5576         int ret;
5577
5578         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5579                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5580                                         buf->start, buf->len,
5581                                         parent, root->root_key.objectid,
5582                                         btrfs_header_level(buf),
5583                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5584                 BUG_ON(ret); /* -ENOMEM */
5585         }
5586
5587         if (!last_ref)
5588                 return;
5589
5590         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5591
5592         if (btrfs_header_generation(buf) == trans->transid) {
5593                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5594                         ret = check_ref_cleanup(trans, root, buf->start);
5595                         if (!ret)
5596                                 goto out;
5597                 }
5598
5599                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5600                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5601                         goto out;
5602                 }
5603
5604                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5605
5606                 btrfs_add_free_space(cache, buf->start, buf->len);
5607                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5608         }
5609 out:
5610         /*
5611          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5612          * anymore.
5613          */
5614         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5615         btrfs_put_block_group(cache);
5616 }
5617
5618 /* Can return -ENOMEM */
5619 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5620                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5621                       u64 owner, u64 offset, int for_cow)
5622 {
5623         int ret;
5624         struct btrfs_fs_info *fs_info = root->fs_info;
5625
5626         /*
5627          * tree log blocks never actually go into the extent allocation
5628          * tree, just update pinning info and exit early.
5629          */
5630         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5631                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5632                 /* unlocks the pinned mutex */
5633                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5634                 ret = 0;
5635         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5636                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5637                                         num_bytes,
5638                                         parent, root_objectid, (int)owner,
5639                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5640         } else {
5641                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5642                                                 num_bytes,
5643                                                 parent, root_objectid, owner,
5644                                                 offset, BTRFS_DROP_DELAYED_REF,
5645                                                 NULL, for_cow);
5646         }
5647         return ret;
5648 }
5649
5650 static u64 stripe_align(struct btrfs_root *root,
5651                         struct btrfs_block_group_cache *cache,
5652                         u64 val, u64 num_bytes)
5653 {
5654         u64 ret = ALIGN(val, root->stripesize);
5655         return ret;
5656 }
5657
5658 /*
5659  * when we wait for progress in the block group caching, its because
5660  * our allocation attempt failed at least once.  So, we must sleep
5661  * and let some progress happen before we try again.
5662  *
5663  * This function will sleep at least once waiting for new free space to
5664  * show up, and then it will check the block group free space numbers
5665  * for our min num_bytes.  Another option is to have it go ahead
5666  * and look in the rbtree for a free extent of a given size, but this
5667  * is a good start.
5668  */
5669 static noinline int
5670 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5671                                 u64 num_bytes)
5672 {
5673         struct btrfs_caching_control *caching_ctl;
5674
5675         caching_ctl = get_caching_control(cache);
5676         if (!caching_ctl)
5677                 return 0;
5678
5679         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5680                    (cache->free_space_ctl->free_space >= num_bytes));
5681
5682         put_caching_control(caching_ctl);
5683         return 0;
5684 }
5685
5686 static noinline int
5687 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5688 {
5689         struct btrfs_caching_control *caching_ctl;
5690
5691         caching_ctl = get_caching_control(cache);
5692         if (!caching_ctl)
5693                 return 0;
5694
5695         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5696
5697         put_caching_control(caching_ctl);
5698         return 0;
5699 }
5700
5701 int __get_raid_index(u64 flags)
5702 {
5703         if (flags & BTRFS_BLOCK_GROUP_RAID10)
5704                 return BTRFS_RAID_RAID10;
5705         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
5706                 return BTRFS_RAID_RAID1;
5707         else if (flags & BTRFS_BLOCK_GROUP_DUP)
5708                 return BTRFS_RAID_DUP;
5709         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
5710                 return BTRFS_RAID_RAID0;
5711         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
5712                 return BTRFS_RAID_RAID5;
5713         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
5714                 return BTRFS_RAID_RAID6;
5715
5716         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
5717 }
5718
5719 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5720 {
5721         return __get_raid_index(cache->flags);
5722 }
5723
5724 enum btrfs_loop_type {
5725         LOOP_CACHING_NOWAIT = 0,
5726         LOOP_CACHING_WAIT = 1,
5727         LOOP_ALLOC_CHUNK = 2,
5728         LOOP_NO_EMPTY_SIZE = 3,
5729 };
5730
5731 /*
5732  * walks the btree of allocated extents and find a hole of a given size.
5733  * The key ins is changed to record the hole:
5734  * ins->objectid == block start
5735  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5736  * ins->offset == number of blocks
5737  * Any available blocks before search_start are skipped.
5738  */
5739 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5740                                      struct btrfs_root *orig_root,
5741                                      u64 num_bytes, u64 empty_size,
5742                                      u64 hint_byte, struct btrfs_key *ins,
5743                                      u64 data)
5744 {
5745         int ret = 0;
5746         struct btrfs_root *root = orig_root->fs_info->extent_root;
5747         struct btrfs_free_cluster *last_ptr = NULL;
5748         struct btrfs_block_group_cache *block_group = NULL;
5749         struct btrfs_block_group_cache *used_block_group;
5750         u64 search_start = 0;
5751         int empty_cluster = 2 * 1024 * 1024;
5752         struct btrfs_space_info *space_info;
5753         int loop = 0;
5754         int index = __get_raid_index(data);
5755         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
5756                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5757         bool found_uncached_bg = false;
5758         bool failed_cluster_refill = false;
5759         bool failed_alloc = false;
5760         bool use_cluster = true;
5761         bool have_caching_bg = false;
5762
5763         WARN_ON(num_bytes < root->sectorsize);
5764         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5765         ins->objectid = 0;
5766         ins->offset = 0;
5767
5768         trace_find_free_extent(orig_root, num_bytes, empty_size, data);
5769
5770         space_info = __find_space_info(root->fs_info, data);
5771         if (!space_info) {
5772                 printk(KERN_ERR "No space info for %llu\n", data);
5773                 return -ENOSPC;
5774         }
5775
5776         /*
5777          * If the space info is for both data and metadata it means we have a
5778          * small filesystem and we can't use the clustering stuff.
5779          */
5780         if (btrfs_mixed_space_info(space_info))
5781                 use_cluster = false;
5782
5783         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5784                 last_ptr = &root->fs_info->meta_alloc_cluster;
5785                 if (!btrfs_test_opt(root, SSD))
5786                         empty_cluster = 64 * 1024;
5787         }
5788
5789         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5790             btrfs_test_opt(root, SSD)) {
5791                 last_ptr = &root->fs_info->data_alloc_cluster;
5792         }
5793
5794         if (last_ptr) {
5795                 spin_lock(&last_ptr->lock);
5796                 if (last_ptr->block_group)
5797                         hint_byte = last_ptr->window_start;
5798                 spin_unlock(&last_ptr->lock);
5799         }
5800
5801         search_start = max(search_start, first_logical_byte(root, 0));
5802         search_start = max(search_start, hint_byte);
5803
5804         if (!last_ptr)
5805                 empty_cluster = 0;
5806
5807         if (search_start == hint_byte) {
5808                 block_group = btrfs_lookup_block_group(root->fs_info,
5809                                                        search_start);
5810                 used_block_group = block_group;
5811                 /*
5812                  * we don't want to use the block group if it doesn't match our
5813                  * allocation bits, or if its not cached.
5814                  *
5815                  * However if we are re-searching with an ideal block group
5816                  * picked out then we don't care that the block group is cached.
5817                  */
5818                 if (block_group && block_group_bits(block_group, data) &&
5819                     block_group->cached != BTRFS_CACHE_NO) {
5820                         down_read(&space_info->groups_sem);
5821                         if (list_empty(&block_group->list) ||
5822                             block_group->ro) {
5823                                 /*
5824                                  * someone is removing this block group,
5825                                  * we can't jump into the have_block_group
5826                                  * target because our list pointers are not
5827                                  * valid
5828                                  */
5829                                 btrfs_put_block_group(block_group);
5830                                 up_read(&space_info->groups_sem);
5831                         } else {
5832                                 index = get_block_group_index(block_group);
5833                                 goto have_block_group;
5834                         }
5835                 } else if (block_group) {
5836                         btrfs_put_block_group(block_group);
5837                 }
5838         }
5839 search:
5840         have_caching_bg = false;
5841         down_read(&space_info->groups_sem);
5842         list_for_each_entry(block_group, &space_info->block_groups[index],
5843                             list) {
5844                 u64 offset;
5845                 int cached;
5846
5847                 used_block_group = block_group;
5848                 btrfs_get_block_group(block_group);
5849                 search_start = block_group->key.objectid;
5850
5851                 /*
5852                  * this can happen if we end up cycling through all the
5853                  * raid types, but we want to make sure we only allocate
5854                  * for the proper type.
5855                  */
5856                 if (!block_group_bits(block_group, data)) {
5857                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5858                                 BTRFS_BLOCK_GROUP_RAID1 |
5859                                 BTRFS_BLOCK_GROUP_RAID5 |
5860                                 BTRFS_BLOCK_GROUP_RAID6 |
5861                                 BTRFS_BLOCK_GROUP_RAID10;
5862
5863                         /*
5864                          * if they asked for extra copies and this block group
5865                          * doesn't provide them, bail.  This does allow us to
5866                          * fill raid0 from raid1.
5867                          */
5868                         if ((data & extra) && !(block_group->flags & extra))
5869                                 goto loop;
5870                 }
5871
5872 have_block_group:
5873                 cached = block_group_cache_done(block_group);
5874                 if (unlikely(!cached)) {
5875                         found_uncached_bg = true;
5876                         ret = cache_block_group(block_group, 0);
5877                         BUG_ON(ret < 0);
5878                         ret = 0;
5879                 }
5880
5881                 if (unlikely(block_group->ro))
5882                         goto loop;
5883
5884                 /*
5885                  * Ok we want to try and use the cluster allocator, so
5886                  * lets look there
5887                  */
5888                 if (last_ptr) {
5889                         unsigned long aligned_cluster;
5890                         /*
5891                          * the refill lock keeps out other
5892                          * people trying to start a new cluster
5893                          */
5894                         spin_lock(&last_ptr->refill_lock);
5895                         used_block_group = last_ptr->block_group;
5896                         if (used_block_group != block_group &&
5897                             (!used_block_group ||
5898                              used_block_group->ro ||
5899                              !block_group_bits(used_block_group, data))) {
5900                                 used_block_group = block_group;
5901                                 goto refill_cluster;
5902                         }
5903
5904                         if (used_block_group != block_group)
5905                                 btrfs_get_block_group(used_block_group);
5906
5907                         offset = btrfs_alloc_from_cluster(used_block_group,
5908                           last_ptr, num_bytes, used_block_group->key.objectid);
5909                         if (offset) {
5910                                 /* we have a block, we're done */
5911                                 spin_unlock(&last_ptr->refill_lock);
5912                                 trace_btrfs_reserve_extent_cluster(root,
5913                                         block_group, search_start, num_bytes);
5914                                 goto checks;
5915                         }
5916
5917                         WARN_ON(last_ptr->block_group != used_block_group);
5918                         if (used_block_group != block_group) {
5919                                 btrfs_put_block_group(used_block_group);
5920                                 used_block_group = block_group;
5921                         }
5922 refill_cluster:
5923                         BUG_ON(used_block_group != block_group);
5924                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
5925                          * set up a new clusters, so lets just skip it
5926                          * and let the allocator find whatever block
5927                          * it can find.  If we reach this point, we
5928                          * will have tried the cluster allocator
5929                          * plenty of times and not have found
5930                          * anything, so we are likely way too
5931                          * fragmented for the clustering stuff to find
5932                          * anything.
5933                          *
5934                          * However, if the cluster is taken from the
5935                          * current block group, release the cluster
5936                          * first, so that we stand a better chance of
5937                          * succeeding in the unclustered
5938                          * allocation.  */
5939                         if (loop >= LOOP_NO_EMPTY_SIZE &&
5940                             last_ptr->block_group != block_group) {
5941                                 spin_unlock(&last_ptr->refill_lock);
5942                                 goto unclustered_alloc;
5943                         }
5944
5945                         /*
5946                          * this cluster didn't work out, free it and
5947                          * start over
5948                          */
5949                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5950
5951                         if (loop >= LOOP_NO_EMPTY_SIZE) {
5952                                 spin_unlock(&last_ptr->refill_lock);
5953                                 goto unclustered_alloc;
5954                         }
5955
5956                         aligned_cluster = max_t(unsigned long,
5957                                                 empty_cluster + empty_size,
5958                                               block_group->full_stripe_len);
5959
5960                         /* allocate a cluster in this block group */
5961                         ret = btrfs_find_space_cluster(trans, root,
5962                                                block_group, last_ptr,
5963                                                search_start, num_bytes,
5964                                                aligned_cluster);
5965                         if (ret == 0) {
5966                                 /*
5967                                  * now pull our allocation out of this
5968                                  * cluster
5969                                  */
5970                                 offset = btrfs_alloc_from_cluster(block_group,
5971                                                   last_ptr, num_bytes,
5972                                                   search_start);
5973                                 if (offset) {
5974                                         /* we found one, proceed */
5975                                         spin_unlock(&last_ptr->refill_lock);
5976                                         trace_btrfs_reserve_extent_cluster(root,
5977                                                 block_group, search_start,
5978                                                 num_bytes);
5979                                         goto checks;
5980                                 }
5981                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5982                                    && !failed_cluster_refill) {
5983                                 spin_unlock(&last_ptr->refill_lock);
5984
5985                                 failed_cluster_refill = true;
5986                                 wait_block_group_cache_progress(block_group,
5987                                        num_bytes + empty_cluster + empty_size);
5988                                 goto have_block_group;
5989                         }
5990
5991                         /*
5992                          * at this point we either didn't find a cluster
5993                          * or we weren't able to allocate a block from our
5994                          * cluster.  Free the cluster we've been trying
5995                          * to use, and go to the next block group
5996                          */
5997                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5998                         spin_unlock(&last_ptr->refill_lock);
5999                         goto loop;
6000                 }
6001
6002 unclustered_alloc:
6003                 spin_lock(&block_group->free_space_ctl->tree_lock);
6004                 if (cached &&
6005                     block_group->free_space_ctl->free_space <
6006                     num_bytes + empty_cluster + empty_size) {
6007                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6008                         goto loop;
6009                 }
6010                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6011
6012                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6013                                                     num_bytes, empty_size);
6014                 /*
6015                  * If we didn't find a chunk, and we haven't failed on this
6016                  * block group before, and this block group is in the middle of
6017                  * caching and we are ok with waiting, then go ahead and wait
6018                  * for progress to be made, and set failed_alloc to true.
6019                  *
6020                  * If failed_alloc is true then we've already waited on this
6021                  * block group once and should move on to the next block group.
6022                  */
6023                 if (!offset && !failed_alloc && !cached &&
6024                     loop > LOOP_CACHING_NOWAIT) {
6025                         wait_block_group_cache_progress(block_group,
6026                                                 num_bytes + empty_size);
6027                         failed_alloc = true;
6028                         goto have_block_group;
6029                 } else if (!offset) {
6030                         if (!cached)
6031                                 have_caching_bg = true;
6032                         goto loop;
6033                 }
6034 checks:
6035                 search_start = stripe_align(root, used_block_group,
6036                                             offset, num_bytes);
6037
6038                 /* move on to the next group */
6039                 if (search_start + num_bytes >
6040                     used_block_group->key.objectid + used_block_group->key.offset) {
6041                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6042                         goto loop;
6043                 }
6044
6045                 if (offset < search_start)
6046                         btrfs_add_free_space(used_block_group, offset,
6047                                              search_start - offset);
6048                 BUG_ON(offset > search_start);
6049
6050                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
6051                                                   alloc_type);
6052                 if (ret == -EAGAIN) {
6053                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6054                         goto loop;
6055                 }
6056
6057                 /* we are all good, lets return */
6058                 ins->objectid = search_start;
6059                 ins->offset = num_bytes;
6060
6061                 trace_btrfs_reserve_extent(orig_root, block_group,
6062                                            search_start, num_bytes);
6063                 if (used_block_group != block_group)
6064                         btrfs_put_block_group(used_block_group);
6065                 btrfs_put_block_group(block_group);
6066                 break;
6067 loop:
6068                 failed_cluster_refill = false;
6069                 failed_alloc = false;
6070                 BUG_ON(index != get_block_group_index(block_group));
6071                 if (used_block_group != block_group)
6072                         btrfs_put_block_group(used_block_group);
6073                 btrfs_put_block_group(block_group);
6074         }
6075         up_read(&space_info->groups_sem);
6076
6077         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6078                 goto search;
6079
6080         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6081                 goto search;
6082
6083         /*
6084          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6085          *                      caching kthreads as we move along
6086          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6087          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6088          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6089          *                      again
6090          */
6091         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6092                 index = 0;
6093                 loop++;
6094                 if (loop == LOOP_ALLOC_CHUNK) {
6095                         ret = do_chunk_alloc(trans, root, data,
6096                                              CHUNK_ALLOC_FORCE);
6097                         /*
6098                          * Do not bail out on ENOSPC since we
6099                          * can do more things.
6100                          */
6101                         if (ret < 0 && ret != -ENOSPC) {
6102                                 btrfs_abort_transaction(trans,
6103                                                         root, ret);
6104                                 goto out;
6105                         }
6106                 }
6107
6108                 if (loop == LOOP_NO_EMPTY_SIZE) {
6109                         empty_size = 0;
6110                         empty_cluster = 0;
6111                 }
6112
6113                 goto search;
6114         } else if (!ins->objectid) {
6115                 ret = -ENOSPC;
6116         } else if (ins->objectid) {
6117                 ret = 0;
6118         }
6119 out:
6120
6121         return ret;
6122 }
6123
6124 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6125                             int dump_block_groups)
6126 {
6127         struct btrfs_block_group_cache *cache;
6128         int index = 0;
6129
6130         spin_lock(&info->lock);
6131         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
6132                (unsigned long long)info->flags,
6133                (unsigned long long)(info->total_bytes - info->bytes_used -
6134                                     info->bytes_pinned - info->bytes_reserved -
6135                                     info->bytes_readonly),
6136                (info->full) ? "" : "not ");
6137         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
6138                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6139                (unsigned long long)info->total_bytes,
6140                (unsigned long long)info->bytes_used,
6141                (unsigned long long)info->bytes_pinned,
6142                (unsigned long long)info->bytes_reserved,
6143                (unsigned long long)info->bytes_may_use,
6144                (unsigned long long)info->bytes_readonly);
6145         spin_unlock(&info->lock);
6146
6147         if (!dump_block_groups)
6148                 return;
6149
6150         down_read(&info->groups_sem);
6151 again:
6152         list_for_each_entry(cache, &info->block_groups[index], list) {
6153                 spin_lock(&cache->lock);
6154                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
6155                        (unsigned long long)cache->key.objectid,
6156                        (unsigned long long)cache->key.offset,
6157                        (unsigned long long)btrfs_block_group_used(&cache->item),
6158                        (unsigned long long)cache->pinned,
6159                        (unsigned long long)cache->reserved,
6160                        cache->ro ? "[readonly]" : "");
6161                 btrfs_dump_free_space(cache, bytes);
6162                 spin_unlock(&cache->lock);
6163         }
6164         if (++index < BTRFS_NR_RAID_TYPES)
6165                 goto again;
6166         up_read(&info->groups_sem);
6167 }
6168
6169 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
6170                          struct btrfs_root *root,
6171                          u64 num_bytes, u64 min_alloc_size,
6172                          u64 empty_size, u64 hint_byte,
6173                          struct btrfs_key *ins, u64 data)
6174 {
6175         bool final_tried = false;
6176         int ret;
6177
6178         data = btrfs_get_alloc_profile(root, data);
6179 again:
6180         WARN_ON(num_bytes < root->sectorsize);
6181         ret = find_free_extent(trans, root, num_bytes, empty_size,
6182                                hint_byte, ins, data);
6183
6184         if (ret == -ENOSPC) {
6185                 if (!final_tried) {
6186                         num_bytes = num_bytes >> 1;
6187                         num_bytes = round_down(num_bytes, root->sectorsize);
6188                         num_bytes = max(num_bytes, min_alloc_size);
6189                         if (num_bytes == min_alloc_size)
6190                                 final_tried = true;
6191                         goto again;
6192                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6193                         struct btrfs_space_info *sinfo;
6194
6195                         sinfo = __find_space_info(root->fs_info, data);
6196                         printk(KERN_ERR "btrfs allocation failed flags %llu, "
6197                                "wanted %llu\n", (unsigned long long)data,
6198                                (unsigned long long)num_bytes);
6199                         if (sinfo)
6200                                 dump_space_info(sinfo, num_bytes, 1);
6201                 }
6202         }
6203
6204         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
6205
6206         return ret;
6207 }
6208
6209 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6210                                         u64 start, u64 len, int pin)
6211 {
6212         struct btrfs_block_group_cache *cache;
6213         int ret = 0;
6214
6215         cache = btrfs_lookup_block_group(root->fs_info, start);
6216         if (!cache) {
6217                 printk(KERN_ERR "Unable to find block group for %llu\n",
6218                        (unsigned long long)start);
6219                 return -ENOSPC;
6220         }
6221
6222         if (btrfs_test_opt(root, DISCARD))
6223                 ret = btrfs_discard_extent(root, start, len, NULL);
6224
6225         if (pin)
6226                 pin_down_extent(root, cache, start, len, 1);
6227         else {
6228                 btrfs_add_free_space(cache, start, len);
6229                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6230         }
6231         btrfs_put_block_group(cache);
6232
6233         trace_btrfs_reserved_extent_free(root, start, len);
6234
6235         return ret;
6236 }
6237
6238 int btrfs_free_reserved_extent(struct btrfs_root *root,
6239                                         u64 start, u64 len)
6240 {
6241         return __btrfs_free_reserved_extent(root, start, len, 0);
6242 }
6243
6244 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6245                                        u64 start, u64 len)
6246 {
6247         return __btrfs_free_reserved_extent(root, start, len, 1);
6248 }
6249
6250 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6251                                       struct btrfs_root *root,
6252                                       u64 parent, u64 root_objectid,
6253                                       u64 flags, u64 owner, u64 offset,
6254                                       struct btrfs_key *ins, int ref_mod)
6255 {
6256         int ret;
6257         struct btrfs_fs_info *fs_info = root->fs_info;
6258         struct btrfs_extent_item *extent_item;
6259         struct btrfs_extent_inline_ref *iref;
6260         struct btrfs_path *path;
6261         struct extent_buffer *leaf;
6262         int type;
6263         u32 size;
6264
6265         if (parent > 0)
6266                 type = BTRFS_SHARED_DATA_REF_KEY;
6267         else
6268                 type = BTRFS_EXTENT_DATA_REF_KEY;
6269
6270         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6271
6272         path = btrfs_alloc_path();
6273         if (!path)
6274                 return -ENOMEM;
6275
6276         path->leave_spinning = 1;
6277         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6278                                       ins, size);
6279         if (ret) {
6280                 btrfs_free_path(path);
6281                 return ret;
6282         }
6283
6284         leaf = path->nodes[0];
6285         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6286                                      struct btrfs_extent_item);
6287         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6288         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6289         btrfs_set_extent_flags(leaf, extent_item,
6290                                flags | BTRFS_EXTENT_FLAG_DATA);
6291
6292         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6293         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6294         if (parent > 0) {
6295                 struct btrfs_shared_data_ref *ref;
6296                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6297                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6298                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6299         } else {
6300                 struct btrfs_extent_data_ref *ref;
6301                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6302                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6303                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6304                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6305                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6306         }
6307
6308         btrfs_mark_buffer_dirty(path->nodes[0]);
6309         btrfs_free_path(path);
6310
6311         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6312         if (ret) { /* -ENOENT, logic error */
6313                 printk(KERN_ERR "btrfs update block group failed for %llu "
6314                        "%llu\n", (unsigned long long)ins->objectid,
6315                        (unsigned long long)ins->offset);
6316                 BUG();
6317         }
6318         return ret;
6319 }
6320
6321 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6322                                      struct btrfs_root *root,
6323                                      u64 parent, u64 root_objectid,
6324                                      u64 flags, struct btrfs_disk_key *key,
6325                                      int level, struct btrfs_key *ins)
6326 {
6327         int ret;
6328         struct btrfs_fs_info *fs_info = root->fs_info;
6329         struct btrfs_extent_item *extent_item;
6330         struct btrfs_tree_block_info *block_info;
6331         struct btrfs_extent_inline_ref *iref;
6332         struct btrfs_path *path;
6333         struct extent_buffer *leaf;
6334         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
6335
6336         path = btrfs_alloc_path();
6337         if (!path)
6338                 return -ENOMEM;
6339
6340         path->leave_spinning = 1;
6341         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6342                                       ins, size);
6343         if (ret) {
6344                 btrfs_free_path(path);
6345                 return ret;
6346         }
6347
6348         leaf = path->nodes[0];
6349         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6350                                      struct btrfs_extent_item);
6351         btrfs_set_extent_refs(leaf, extent_item, 1);
6352         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6353         btrfs_set_extent_flags(leaf, extent_item,
6354                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6355         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6356
6357         btrfs_set_tree_block_key(leaf, block_info, key);
6358         btrfs_set_tree_block_level(leaf, block_info, level);
6359
6360         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6361         if (parent > 0) {
6362                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6363                 btrfs_set_extent_inline_ref_type(leaf, iref,
6364                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6365                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6366         } else {
6367                 btrfs_set_extent_inline_ref_type(leaf, iref,
6368                                                  BTRFS_TREE_BLOCK_REF_KEY);
6369                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6370         }
6371
6372         btrfs_mark_buffer_dirty(leaf);
6373         btrfs_free_path(path);
6374
6375         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6376         if (ret) { /* -ENOENT, logic error */
6377                 printk(KERN_ERR "btrfs update block group failed for %llu "
6378                        "%llu\n", (unsigned long long)ins->objectid,
6379                        (unsigned long long)ins->offset);
6380                 BUG();
6381         }
6382         return ret;
6383 }
6384
6385 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6386                                      struct btrfs_root *root,
6387                                      u64 root_objectid, u64 owner,
6388                                      u64 offset, struct btrfs_key *ins)
6389 {
6390         int ret;
6391
6392         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6393
6394         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6395                                          ins->offset, 0,
6396                                          root_objectid, owner, offset,
6397                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6398         return ret;
6399 }
6400
6401 /*
6402  * this is used by the tree logging recovery code.  It records that
6403  * an extent has been allocated and makes sure to clear the free
6404  * space cache bits as well
6405  */
6406 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6407                                    struct btrfs_root *root,
6408                                    u64 root_objectid, u64 owner, u64 offset,
6409                                    struct btrfs_key *ins)
6410 {
6411         int ret;
6412         struct btrfs_block_group_cache *block_group;
6413         struct btrfs_caching_control *caching_ctl;
6414         u64 start = ins->objectid;
6415         u64 num_bytes = ins->offset;
6416
6417         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6418         cache_block_group(block_group, 0);
6419         caching_ctl = get_caching_control(block_group);
6420
6421         if (!caching_ctl) {
6422                 BUG_ON(!block_group_cache_done(block_group));
6423                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6424                 BUG_ON(ret); /* -ENOMEM */
6425         } else {
6426                 mutex_lock(&caching_ctl->mutex);
6427
6428                 if (start >= caching_ctl->progress) {
6429                         ret = add_excluded_extent(root, start, num_bytes);
6430                         BUG_ON(ret); /* -ENOMEM */
6431                 } else if (start + num_bytes <= caching_ctl->progress) {
6432                         ret = btrfs_remove_free_space(block_group,
6433                                                       start, num_bytes);
6434                         BUG_ON(ret); /* -ENOMEM */
6435                 } else {
6436                         num_bytes = caching_ctl->progress - start;
6437                         ret = btrfs_remove_free_space(block_group,
6438                                                       start, num_bytes);
6439                         BUG_ON(ret); /* -ENOMEM */
6440
6441                         start = caching_ctl->progress;
6442                         num_bytes = ins->objectid + ins->offset -
6443                                     caching_ctl->progress;
6444                         ret = add_excluded_extent(root, start, num_bytes);
6445                         BUG_ON(ret); /* -ENOMEM */
6446                 }
6447
6448                 mutex_unlock(&caching_ctl->mutex);
6449                 put_caching_control(caching_ctl);
6450         }
6451
6452         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6453                                           RESERVE_ALLOC_NO_ACCOUNT);
6454         BUG_ON(ret); /* logic error */
6455         btrfs_put_block_group(block_group);
6456         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6457                                          0, owner, offset, ins, 1);
6458         return ret;
6459 }
6460
6461 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
6462                                             struct btrfs_root *root,
6463                                             u64 bytenr, u32 blocksize,
6464                                             int level)
6465 {
6466         struct extent_buffer *buf;
6467
6468         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6469         if (!buf)
6470                 return ERR_PTR(-ENOMEM);
6471         btrfs_set_header_generation(buf, trans->transid);
6472         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6473         btrfs_tree_lock(buf);
6474         clean_tree_block(trans, root, buf);
6475         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6476
6477         btrfs_set_lock_blocking(buf);
6478         btrfs_set_buffer_uptodate(buf);
6479
6480         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6481                 /*
6482                  * we allow two log transactions at a time, use different
6483                  * EXENT bit to differentiate dirty pages.
6484                  */
6485                 if (root->log_transid % 2 == 0)
6486                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6487                                         buf->start + buf->len - 1, GFP_NOFS);
6488                 else
6489                         set_extent_new(&root->dirty_log_pages, buf->start,
6490                                         buf->start + buf->len - 1, GFP_NOFS);
6491         } else {
6492                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6493                          buf->start + buf->len - 1, GFP_NOFS);
6494         }
6495         trans->blocks_used++;
6496         /* this returns a buffer locked for blocking */
6497         return buf;
6498 }
6499
6500 static struct btrfs_block_rsv *
6501 use_block_rsv(struct btrfs_trans_handle *trans,
6502               struct btrfs_root *root, u32 blocksize)
6503 {
6504         struct btrfs_block_rsv *block_rsv;
6505         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6506         int ret;
6507
6508         block_rsv = get_block_rsv(trans, root);
6509
6510         if (block_rsv->size == 0) {
6511                 ret = reserve_metadata_bytes(root, block_rsv, blocksize,
6512                                              BTRFS_RESERVE_NO_FLUSH);
6513                 /*
6514                  * If we couldn't reserve metadata bytes try and use some from
6515                  * the global reserve.
6516                  */
6517                 if (ret && block_rsv != global_rsv) {
6518                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6519                         if (!ret)
6520                                 return global_rsv;
6521                         return ERR_PTR(ret);
6522                 } else if (ret) {
6523                         return ERR_PTR(ret);
6524                 }
6525                 return block_rsv;
6526         }
6527
6528         ret = block_rsv_use_bytes(block_rsv, blocksize);
6529         if (!ret)
6530                 return block_rsv;
6531         if (ret && !block_rsv->failfast) {
6532                 if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6533                         static DEFINE_RATELIMIT_STATE(_rs,
6534                                         DEFAULT_RATELIMIT_INTERVAL * 10,
6535                                         /*DEFAULT_RATELIMIT_BURST*/ 1);
6536                         if (__ratelimit(&_rs))
6537                                 WARN(1, KERN_DEBUG
6538                                         "btrfs: block rsv returned %d\n", ret);
6539                 }
6540                 ret = reserve_metadata_bytes(root, block_rsv, blocksize,
6541                                              BTRFS_RESERVE_NO_FLUSH);
6542                 if (!ret) {
6543                         return block_rsv;
6544                 } else if (ret && block_rsv != global_rsv) {
6545                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6546                         if (!ret)
6547                                 return global_rsv;
6548                 }
6549         }
6550
6551         return ERR_PTR(-ENOSPC);
6552 }
6553
6554 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6555                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6556 {
6557         block_rsv_add_bytes(block_rsv, blocksize, 0);
6558         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6559 }
6560
6561 /*
6562  * finds a free extent and does all the dirty work required for allocation
6563  * returns the key for the extent through ins, and a tree buffer for
6564  * the first block of the extent through buf.
6565  *
6566  * returns the tree buffer or NULL.
6567  */
6568 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6569                                         struct btrfs_root *root, u32 blocksize,
6570                                         u64 parent, u64 root_objectid,
6571                                         struct btrfs_disk_key *key, int level,
6572                                         u64 hint, u64 empty_size)
6573 {
6574         struct btrfs_key ins;
6575         struct btrfs_block_rsv *block_rsv;
6576         struct extent_buffer *buf;
6577         u64 flags = 0;
6578         int ret;
6579
6580
6581         block_rsv = use_block_rsv(trans, root, blocksize);
6582         if (IS_ERR(block_rsv))
6583                 return ERR_CAST(block_rsv);
6584
6585         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6586                                    empty_size, hint, &ins, 0);
6587         if (ret) {
6588                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6589                 return ERR_PTR(ret);
6590         }
6591
6592         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6593                                     blocksize, level);
6594         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6595
6596         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6597                 if (parent == 0)
6598                         parent = ins.objectid;
6599                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6600         } else
6601                 BUG_ON(parent > 0);
6602
6603         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6604                 struct btrfs_delayed_extent_op *extent_op;
6605                 extent_op = btrfs_alloc_delayed_extent_op();
6606                 BUG_ON(!extent_op); /* -ENOMEM */
6607                 if (key)
6608                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6609                 else
6610                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6611                 extent_op->flags_to_set = flags;
6612                 extent_op->update_key = 1;
6613                 extent_op->update_flags = 1;
6614                 extent_op->is_data = 0;
6615
6616                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6617                                         ins.objectid,
6618                                         ins.offset, parent, root_objectid,
6619                                         level, BTRFS_ADD_DELAYED_EXTENT,
6620                                         extent_op, 0);
6621                 BUG_ON(ret); /* -ENOMEM */
6622         }
6623         return buf;
6624 }
6625
6626 struct walk_control {
6627         u64 refs[BTRFS_MAX_LEVEL];
6628         u64 flags[BTRFS_MAX_LEVEL];
6629         struct btrfs_key update_progress;
6630         int stage;
6631         int level;
6632         int shared_level;
6633         int update_ref;
6634         int keep_locks;
6635         int reada_slot;
6636         int reada_count;
6637         int for_reloc;
6638 };
6639
6640 #define DROP_REFERENCE  1
6641 #define UPDATE_BACKREF  2
6642
6643 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6644                                      struct btrfs_root *root,
6645                                      struct walk_control *wc,
6646                                      struct btrfs_path *path)
6647 {
6648         u64 bytenr;
6649         u64 generation;
6650         u64 refs;
6651         u64 flags;
6652         u32 nritems;
6653         u32 blocksize;
6654         struct btrfs_key key;
6655         struct extent_buffer *eb;
6656         int ret;
6657         int slot;
6658         int nread = 0;
6659
6660         if (path->slots[wc->level] < wc->reada_slot) {
6661                 wc->reada_count = wc->reada_count * 2 / 3;
6662                 wc->reada_count = max(wc->reada_count, 2);
6663         } else {
6664                 wc->reada_count = wc->reada_count * 3 / 2;
6665                 wc->reada_count = min_t(int, wc->reada_count,
6666                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6667         }
6668
6669         eb = path->nodes[wc->level];
6670         nritems = btrfs_header_nritems(eb);
6671         blocksize = btrfs_level_size(root, wc->level - 1);
6672
6673         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6674                 if (nread >= wc->reada_count)
6675                         break;
6676
6677                 cond_resched();
6678                 bytenr = btrfs_node_blockptr(eb, slot);
6679                 generation = btrfs_node_ptr_generation(eb, slot);
6680
6681                 if (slot == path->slots[wc->level])
6682                         goto reada;
6683
6684                 if (wc->stage == UPDATE_BACKREF &&
6685                     generation <= root->root_key.offset)
6686                         continue;
6687
6688                 /* We don't lock the tree block, it's OK to be racy here */
6689                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6690                                                &refs, &flags);
6691                 /* We don't care about errors in readahead. */
6692                 if (ret < 0)
6693                         continue;
6694                 BUG_ON(refs == 0);
6695
6696                 if (wc->stage == DROP_REFERENCE) {
6697                         if (refs == 1)
6698                                 goto reada;
6699
6700                         if (wc->level == 1 &&
6701                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6702                                 continue;
6703                         if (!wc->update_ref ||
6704                             generation <= root->root_key.offset)
6705                                 continue;
6706                         btrfs_node_key_to_cpu(eb, &key, slot);
6707                         ret = btrfs_comp_cpu_keys(&key,
6708                                                   &wc->update_progress);
6709                         if (ret < 0)
6710                                 continue;
6711                 } else {
6712                         if (wc->level == 1 &&
6713                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6714                                 continue;
6715                 }
6716 reada:
6717                 ret = readahead_tree_block(root, bytenr, blocksize,
6718                                            generation);
6719                 if (ret)
6720                         break;
6721                 nread++;
6722         }
6723         wc->reada_slot = slot;
6724 }
6725
6726 /*
6727  * hepler to process tree block while walking down the tree.
6728  *
6729  * when wc->stage == UPDATE_BACKREF, this function updates
6730  * back refs for pointers in the block.
6731  *
6732  * NOTE: return value 1 means we should stop walking down.
6733  */
6734 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6735                                    struct btrfs_root *root,
6736                                    struct btrfs_path *path,
6737                                    struct walk_control *wc, int lookup_info)
6738 {
6739         int level = wc->level;
6740         struct extent_buffer *eb = path->nodes[level];
6741         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6742         int ret;
6743
6744         if (wc->stage == UPDATE_BACKREF &&
6745             btrfs_header_owner(eb) != root->root_key.objectid)
6746                 return 1;
6747
6748         /*
6749          * when reference count of tree block is 1, it won't increase
6750          * again. once full backref flag is set, we never clear it.
6751          */
6752         if (lookup_info &&
6753             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6754              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6755                 BUG_ON(!path->locks[level]);
6756                 ret = btrfs_lookup_extent_info(trans, root,
6757                                                eb->start, eb->len,
6758                                                &wc->refs[level],
6759                                                &wc->flags[level]);
6760                 BUG_ON(ret == -ENOMEM);
6761                 if (ret)
6762                         return ret;
6763                 BUG_ON(wc->refs[level] == 0);
6764         }
6765
6766         if (wc->stage == DROP_REFERENCE) {
6767                 if (wc->refs[level] > 1)
6768                         return 1;
6769
6770                 if (path->locks[level] && !wc->keep_locks) {
6771                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6772                         path->locks[level] = 0;
6773                 }
6774                 return 0;
6775         }
6776
6777         /* wc->stage == UPDATE_BACKREF */
6778         if (!(wc->flags[level] & flag)) {
6779                 BUG_ON(!path->locks[level]);
6780                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
6781                 BUG_ON(ret); /* -ENOMEM */
6782                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
6783                 BUG_ON(ret); /* -ENOMEM */
6784                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6785                                                   eb->len, flag, 0);
6786                 BUG_ON(ret); /* -ENOMEM */
6787                 wc->flags[level] |= flag;
6788         }
6789
6790         /*
6791          * the block is shared by multiple trees, so it's not good to
6792          * keep the tree lock
6793          */
6794         if (path->locks[level] && level > 0) {
6795                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6796                 path->locks[level] = 0;
6797         }
6798         return 0;
6799 }
6800
6801 /*
6802  * hepler to process tree block pointer.
6803  *
6804  * when wc->stage == DROP_REFERENCE, this function checks
6805  * reference count of the block pointed to. if the block
6806  * is shared and we need update back refs for the subtree
6807  * rooted at the block, this function changes wc->stage to
6808  * UPDATE_BACKREF. if the block is shared and there is no
6809  * need to update back, this function drops the reference
6810  * to the block.
6811  *
6812  * NOTE: return value 1 means we should stop walking down.
6813  */
6814 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6815                                  struct btrfs_root *root,
6816                                  struct btrfs_path *path,
6817                                  struct walk_control *wc, int *lookup_info)
6818 {
6819         u64 bytenr;
6820         u64 generation;
6821         u64 parent;
6822         u32 blocksize;
6823         struct btrfs_key key;
6824         struct extent_buffer *next;
6825         int level = wc->level;
6826         int reada = 0;
6827         int ret = 0;
6828
6829         generation = btrfs_node_ptr_generation(path->nodes[level],
6830                                                path->slots[level]);
6831         /*
6832          * if the lower level block was created before the snapshot
6833          * was created, we know there is no need to update back refs
6834          * for the subtree
6835          */
6836         if (wc->stage == UPDATE_BACKREF &&
6837             generation <= root->root_key.offset) {
6838                 *lookup_info = 1;
6839                 return 1;
6840         }
6841
6842         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6843         blocksize = btrfs_level_size(root, level - 1);
6844
6845         next = btrfs_find_tree_block(root, bytenr, blocksize);
6846         if (!next) {
6847                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6848                 if (!next)
6849                         return -ENOMEM;
6850                 reada = 1;
6851         }
6852         btrfs_tree_lock(next);
6853         btrfs_set_lock_blocking(next);
6854
6855         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6856                                        &wc->refs[level - 1],
6857                                        &wc->flags[level - 1]);
6858         if (ret < 0) {
6859                 btrfs_tree_unlock(next);
6860                 return ret;
6861         }
6862
6863         BUG_ON(wc->refs[level - 1] == 0);
6864         *lookup_info = 0;
6865
6866         if (wc->stage == DROP_REFERENCE) {
6867                 if (wc->refs[level - 1] > 1) {
6868                         if (level == 1 &&
6869                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6870                                 goto skip;
6871
6872                         if (!wc->update_ref ||
6873                             generation <= root->root_key.offset)
6874                                 goto skip;
6875
6876                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6877                                               path->slots[level]);
6878                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6879                         if (ret < 0)
6880                                 goto skip;
6881
6882                         wc->stage = UPDATE_BACKREF;
6883                         wc->shared_level = level - 1;
6884                 }
6885         } else {
6886                 if (level == 1 &&
6887                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6888                         goto skip;
6889         }
6890
6891         if (!btrfs_buffer_uptodate(next, generation, 0)) {
6892                 btrfs_tree_unlock(next);
6893                 free_extent_buffer(next);
6894                 next = NULL;
6895                 *lookup_info = 1;
6896         }
6897
6898         if (!next) {
6899                 if (reada && level == 1)
6900                         reada_walk_down(trans, root, wc, path);
6901                 next = read_tree_block(root, bytenr, blocksize, generation);
6902                 if (!next)
6903                         return -EIO;
6904                 btrfs_tree_lock(next);
6905                 btrfs_set_lock_blocking(next);
6906         }
6907
6908         level--;
6909         BUG_ON(level != btrfs_header_level(next));
6910         path->nodes[level] = next;
6911         path->slots[level] = 0;
6912         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6913         wc->level = level;
6914         if (wc->level == 1)
6915                 wc->reada_slot = 0;
6916         return 0;
6917 skip:
6918         wc->refs[level - 1] = 0;
6919         wc->flags[level - 1] = 0;
6920         if (wc->stage == DROP_REFERENCE) {
6921                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6922                         parent = path->nodes[level]->start;
6923                 } else {
6924                         BUG_ON(root->root_key.objectid !=
6925                                btrfs_header_owner(path->nodes[level]));
6926                         parent = 0;
6927                 }
6928
6929                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6930                                 root->root_key.objectid, level - 1, 0, 0);
6931                 BUG_ON(ret); /* -ENOMEM */
6932         }
6933         btrfs_tree_unlock(next);
6934         free_extent_buffer(next);
6935         *lookup_info = 1;
6936         return 1;
6937 }
6938
6939 /*
6940  * hepler to process tree block while walking up the tree.
6941  *
6942  * when wc->stage == DROP_REFERENCE, this function drops
6943  * reference count on the block.
6944  *
6945  * when wc->stage == UPDATE_BACKREF, this function changes
6946  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6947  * to UPDATE_BACKREF previously while processing the block.
6948  *
6949  * NOTE: return value 1 means we should stop walking up.
6950  */
6951 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6952                                  struct btrfs_root *root,
6953                                  struct btrfs_path *path,
6954                                  struct walk_control *wc)
6955 {
6956         int ret;
6957         int level = wc->level;
6958         struct extent_buffer *eb = path->nodes[level];
6959         u64 parent = 0;
6960
6961         if (wc->stage == UPDATE_BACKREF) {
6962                 BUG_ON(wc->shared_level < level);
6963                 if (level < wc->shared_level)
6964                         goto out;
6965
6966                 ret = find_next_key(path, level + 1, &wc->update_progress);
6967                 if (ret > 0)
6968                         wc->update_ref = 0;
6969
6970                 wc->stage = DROP_REFERENCE;
6971                 wc->shared_level = -1;
6972                 path->slots[level] = 0;
6973
6974                 /*
6975                  * check reference count again if the block isn't locked.
6976                  * we should start walking down the tree again if reference
6977                  * count is one.
6978                  */
6979                 if (!path->locks[level]) {
6980                         BUG_ON(level == 0);
6981                         btrfs_tree_lock(eb);
6982                         btrfs_set_lock_blocking(eb);
6983                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6984
6985                         ret = btrfs_lookup_extent_info(trans, root,
6986                                                        eb->start, eb->len,
6987                                                        &wc->refs[level],
6988                                                        &wc->flags[level]);
6989                         if (ret < 0) {
6990                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6991                                 path->locks[level] = 0;
6992                                 return ret;
6993                         }
6994                         BUG_ON(wc->refs[level] == 0);
6995                         if (wc->refs[level] == 1) {
6996                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6997                                 path->locks[level] = 0;
6998                                 return 1;
6999                         }
7000                 }
7001         }
7002
7003         /* wc->stage == DROP_REFERENCE */
7004         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7005
7006         if (wc->refs[level] == 1) {
7007                 if (level == 0) {
7008                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7009                                 ret = btrfs_dec_ref(trans, root, eb, 1,
7010                                                     wc->for_reloc);
7011                         else
7012                                 ret = btrfs_dec_ref(trans, root, eb, 0,
7013                                                     wc->for_reloc);
7014                         BUG_ON(ret); /* -ENOMEM */
7015                 }
7016                 /* make block locked assertion in clean_tree_block happy */
7017                 if (!path->locks[level] &&
7018                     btrfs_header_generation(eb) == trans->transid) {
7019                         btrfs_tree_lock(eb);
7020                         btrfs_set_lock_blocking(eb);
7021                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7022                 }
7023                 clean_tree_block(trans, root, eb);
7024         }
7025
7026         if (eb == root->node) {
7027                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7028                         parent = eb->start;
7029                 else
7030                         BUG_ON(root->root_key.objectid !=
7031                                btrfs_header_owner(eb));
7032         } else {
7033                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7034                         parent = path->nodes[level + 1]->start;
7035                 else
7036                         BUG_ON(root->root_key.objectid !=
7037                                btrfs_header_owner(path->nodes[level + 1]));
7038         }
7039
7040         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7041 out:
7042         wc->refs[level] = 0;
7043         wc->flags[level] = 0;
7044         return 0;
7045 }
7046
7047 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7048                                    struct btrfs_root *root,
7049                                    struct btrfs_path *path,
7050                                    struct walk_control *wc)
7051 {
7052         int level = wc->level;
7053         int lookup_info = 1;
7054         int ret;
7055
7056         while (level >= 0) {
7057                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
7058                 if (ret > 0)
7059                         break;
7060
7061                 if (level == 0)
7062                         break;
7063
7064                 if (path->slots[level] >=
7065                     btrfs_header_nritems(path->nodes[level]))
7066                         break;
7067
7068                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
7069                 if (ret > 0) {
7070                         path->slots[level]++;
7071                         continue;
7072                 } else if (ret < 0)
7073                         return ret;
7074                 level = wc->level;
7075         }
7076         return 0;
7077 }
7078
7079 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
7080                                  struct btrfs_root *root,
7081                                  struct btrfs_path *path,
7082                                  struct walk_control *wc, int max_level)
7083 {
7084         int level = wc->level;
7085         int ret;
7086
7087         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
7088         while (level < max_level && path->nodes[level]) {
7089                 wc->level = level;
7090                 if (path->slots[level] + 1 <
7091                     btrfs_header_nritems(path->nodes[level])) {
7092                         path->slots[level]++;
7093                         return 0;
7094                 } else {
7095                         ret = walk_up_proc(trans, root, path, wc);
7096                         if (ret > 0)
7097                                 return 0;
7098
7099                         if (path->locks[level]) {
7100                                 btrfs_tree_unlock_rw(path->nodes[level],
7101                                                      path->locks[level]);
7102                                 path->locks[level] = 0;
7103                         }
7104                         free_extent_buffer(path->nodes[level]);
7105                         path->nodes[level] = NULL;
7106                         level++;
7107                 }
7108         }
7109         return 1;
7110 }
7111
7112 /*
7113  * drop a subvolume tree.
7114  *
7115  * this function traverses the tree freeing any blocks that only
7116  * referenced by the tree.
7117  *
7118  * when a shared tree block is found. this function decreases its
7119  * reference count by one. if update_ref is true, this function
7120  * also make sure backrefs for the shared block and all lower level
7121  * blocks are properly updated.
7122  */
7123 int btrfs_drop_snapshot(struct btrfs_root *root,
7124                          struct btrfs_block_rsv *block_rsv, int update_ref,
7125                          int for_reloc)
7126 {
7127         struct btrfs_path *path;
7128         struct btrfs_trans_handle *trans;
7129         struct btrfs_root *tree_root = root->fs_info->tree_root;
7130         struct btrfs_root_item *root_item = &root->root_item;
7131         struct walk_control *wc;
7132         struct btrfs_key key;
7133         int err = 0;
7134         int ret;
7135         int level;
7136
7137         path = btrfs_alloc_path();
7138         if (!path) {
7139                 err = -ENOMEM;
7140                 goto out;
7141         }
7142
7143         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7144         if (!wc) {
7145                 btrfs_free_path(path);
7146                 err = -ENOMEM;
7147                 goto out;
7148         }
7149
7150         trans = btrfs_start_transaction(tree_root, 0);
7151         if (IS_ERR(trans)) {
7152                 err = PTR_ERR(trans);
7153                 goto out_free;
7154         }
7155
7156         if (block_rsv)
7157                 trans->block_rsv = block_rsv;
7158
7159         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
7160                 level = btrfs_header_level(root->node);
7161                 path->nodes[level] = btrfs_lock_root_node(root);
7162                 btrfs_set_lock_blocking(path->nodes[level]);
7163                 path->slots[level] = 0;
7164                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7165                 memset(&wc->update_progress, 0,
7166                        sizeof(wc->update_progress));
7167         } else {
7168                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
7169                 memcpy(&wc->update_progress, &key,
7170                        sizeof(wc->update_progress));
7171
7172                 level = root_item->drop_level;
7173                 BUG_ON(level == 0);
7174                 path->lowest_level = level;
7175                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
7176                 path->lowest_level = 0;
7177                 if (ret < 0) {
7178                         err = ret;
7179                         goto out_end_trans;
7180                 }
7181                 WARN_ON(ret > 0);
7182
7183                 /*
7184                  * unlock our path, this is safe because only this
7185                  * function is allowed to delete this snapshot
7186                  */
7187                 btrfs_unlock_up_safe(path, 0);
7188
7189                 level = btrfs_header_level(root->node);
7190                 while (1) {
7191                         btrfs_tree_lock(path->nodes[level]);
7192                         btrfs_set_lock_blocking(path->nodes[level]);
7193
7194                         ret = btrfs_lookup_extent_info(trans, root,
7195                                                 path->nodes[level]->start,
7196                                                 path->nodes[level]->len,
7197                                                 &wc->refs[level],
7198                                                 &wc->flags[level]);
7199                         if (ret < 0) {
7200                                 err = ret;
7201                                 goto out_end_trans;
7202                         }
7203                         BUG_ON(wc->refs[level] == 0);
7204
7205                         if (level == root_item->drop_level)
7206                                 break;
7207
7208                         btrfs_tree_unlock(path->nodes[level]);
7209                         WARN_ON(wc->refs[level] != 1);
7210                         level--;
7211                 }
7212         }
7213
7214         wc->level = level;
7215         wc->shared_level = -1;
7216         wc->stage = DROP_REFERENCE;
7217         wc->update_ref = update_ref;
7218         wc->keep_locks = 0;
7219         wc->for_reloc = for_reloc;
7220         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7221
7222         while (1) {
7223                 ret = walk_down_tree(trans, root, path, wc);
7224                 if (ret < 0) {
7225                         err = ret;
7226                         break;
7227                 }
7228
7229                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7230                 if (ret < 0) {
7231                         err = ret;
7232                         break;
7233                 }
7234
7235                 if (ret > 0) {
7236                         BUG_ON(wc->stage != DROP_REFERENCE);
7237                         break;
7238                 }
7239
7240                 if (wc->stage == DROP_REFERENCE) {
7241                         level = wc->level;
7242                         btrfs_node_key(path->nodes[level],
7243                                        &root_item->drop_progress,
7244                                        path->slots[level]);
7245                         root_item->drop_level = level;
7246                 }
7247
7248                 BUG_ON(wc->level == 0);
7249                 if (btrfs_should_end_transaction(trans, tree_root)) {
7250                         ret = btrfs_update_root(trans, tree_root,
7251                                                 &root->root_key,
7252                                                 root_item);
7253                         if (ret) {
7254                                 btrfs_abort_transaction(trans, tree_root, ret);
7255                                 err = ret;
7256                                 goto out_end_trans;
7257                         }
7258
7259                         btrfs_end_transaction_throttle(trans, tree_root);
7260                         trans = btrfs_start_transaction(tree_root, 0);
7261                         if (IS_ERR(trans)) {
7262                                 err = PTR_ERR(trans);
7263                                 goto out_free;
7264                         }
7265                         if (block_rsv)
7266                                 trans->block_rsv = block_rsv;
7267                 }
7268         }
7269         btrfs_release_path(path);
7270         if (err)
7271                 goto out_end_trans;
7272
7273         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7274         if (ret) {
7275                 btrfs_abort_transaction(trans, tree_root, ret);
7276                 goto out_end_trans;
7277         }
7278
7279         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7280                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
7281                                            NULL, NULL);
7282                 if (ret < 0) {
7283                         btrfs_abort_transaction(trans, tree_root, ret);
7284                         err = ret;
7285                         goto out_end_trans;
7286                 } else if (ret > 0) {
7287                         /* if we fail to delete the orphan item this time
7288                          * around, it'll get picked up the next time.
7289                          *
7290                          * The most common failure here is just -ENOENT.
7291                          */
7292                         btrfs_del_orphan_item(trans, tree_root,
7293                                               root->root_key.objectid);
7294                 }
7295         }
7296
7297         if (root->in_radix) {
7298                 btrfs_free_fs_root(tree_root->fs_info, root);
7299         } else {
7300                 free_extent_buffer(root->node);
7301                 free_extent_buffer(root->commit_root);
7302                 kfree(root);
7303         }
7304 out_end_trans:
7305         btrfs_end_transaction_throttle(trans, tree_root);
7306 out_free:
7307         kfree(wc);
7308         btrfs_free_path(path);
7309 out:
7310         if (err)
7311                 btrfs_std_error(root->fs_info, err);
7312         return err;
7313 }
7314
7315 /*
7316  * drop subtree rooted at tree block 'node'.
7317  *
7318  * NOTE: this function will unlock and release tree block 'node'
7319  * only used by relocation code
7320  */
7321 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7322                         struct btrfs_root *root,
7323                         struct extent_buffer *node,
7324                         struct extent_buffer *parent)
7325 {
7326         struct btrfs_path *path;
7327         struct walk_control *wc;
7328         int level;
7329         int parent_level;
7330         int ret = 0;
7331         int wret;
7332
7333         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7334
7335         path = btrfs_alloc_path();
7336         if (!path)
7337                 return -ENOMEM;
7338
7339         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7340         if (!wc) {
7341                 btrfs_free_path(path);
7342                 return -ENOMEM;
7343         }
7344
7345         btrfs_assert_tree_locked(parent);
7346         parent_level = btrfs_header_level(parent);
7347         extent_buffer_get(parent);
7348         path->nodes[parent_level] = parent;
7349         path->slots[parent_level] = btrfs_header_nritems(parent);
7350
7351         btrfs_assert_tree_locked(node);
7352         level = btrfs_header_level(node);
7353         path->nodes[level] = node;
7354         path->slots[level] = 0;
7355         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7356
7357         wc->refs[parent_level] = 1;
7358         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7359         wc->level = level;
7360         wc->shared_level = -1;
7361         wc->stage = DROP_REFERENCE;
7362         wc->update_ref = 0;
7363         wc->keep_locks = 1;
7364         wc->for_reloc = 1;
7365         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7366
7367         while (1) {
7368                 wret = walk_down_tree(trans, root, path, wc);
7369                 if (wret < 0) {
7370                         ret = wret;
7371                         break;
7372                 }
7373
7374                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7375                 if (wret < 0)
7376                         ret = wret;
7377                 if (wret != 0)
7378                         break;
7379         }
7380
7381         kfree(wc);
7382         btrfs_free_path(path);
7383         return ret;
7384 }
7385
7386 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7387 {
7388         u64 num_devices;
7389         u64 stripped;
7390
7391         /*
7392          * if restripe for this chunk_type is on pick target profile and
7393          * return, otherwise do the usual balance
7394          */
7395         stripped = get_restripe_target(root->fs_info, flags);
7396         if (stripped)
7397                 return extended_to_chunk(stripped);
7398
7399         /*
7400          * we add in the count of missing devices because we want
7401          * to make sure that any RAID levels on a degraded FS
7402          * continue to be honored.
7403          */
7404         num_devices = root->fs_info->fs_devices->rw_devices +
7405                 root->fs_info->fs_devices->missing_devices;
7406
7407         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7408                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
7409                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7410
7411         if (num_devices == 1) {
7412                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7413                 stripped = flags & ~stripped;
7414
7415                 /* turn raid0 into single device chunks */
7416                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7417                         return stripped;
7418
7419                 /* turn mirroring into duplication */
7420                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7421                              BTRFS_BLOCK_GROUP_RAID10))
7422                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7423         } else {
7424                 /* they already had raid on here, just return */
7425                 if (flags & stripped)
7426                         return flags;
7427
7428                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7429                 stripped = flags & ~stripped;
7430
7431                 /* switch duplicated blocks with raid1 */
7432                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7433                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7434
7435                 /* this is drive concat, leave it alone */
7436         }
7437
7438         return flags;
7439 }
7440
7441 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7442 {
7443         struct btrfs_space_info *sinfo = cache->space_info;
7444         u64 num_bytes;
7445         u64 min_allocable_bytes;
7446         int ret = -ENOSPC;
7447
7448
7449         /*
7450          * We need some metadata space and system metadata space for
7451          * allocating chunks in some corner cases until we force to set
7452          * it to be readonly.
7453          */
7454         if ((sinfo->flags &
7455              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7456             !force)
7457                 min_allocable_bytes = 1 * 1024 * 1024;
7458         else
7459                 min_allocable_bytes = 0;
7460
7461         spin_lock(&sinfo->lock);
7462         spin_lock(&cache->lock);
7463
7464         if (cache->ro) {
7465                 ret = 0;
7466                 goto out;
7467         }
7468
7469         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7470                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7471
7472         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7473             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7474             min_allocable_bytes <= sinfo->total_bytes) {
7475                 sinfo->bytes_readonly += num_bytes;
7476                 cache->ro = 1;
7477                 ret = 0;
7478         }
7479 out:
7480         spin_unlock(&cache->lock);
7481         spin_unlock(&sinfo->lock);
7482         return ret;
7483 }
7484
7485 int btrfs_set_block_group_ro(struct btrfs_root *root,
7486                              struct btrfs_block_group_cache *cache)
7487
7488 {
7489         struct btrfs_trans_handle *trans;
7490         u64 alloc_flags;
7491         int ret;
7492
7493         BUG_ON(cache->ro);
7494
7495         trans = btrfs_join_transaction(root);
7496         if (IS_ERR(trans))
7497                 return PTR_ERR(trans);
7498
7499         alloc_flags = update_block_group_flags(root, cache->flags);
7500         if (alloc_flags != cache->flags) {
7501                 ret = do_chunk_alloc(trans, root, alloc_flags,
7502                                      CHUNK_ALLOC_FORCE);
7503                 if (ret < 0)
7504                         goto out;
7505         }
7506
7507         ret = set_block_group_ro(cache, 0);
7508         if (!ret)
7509                 goto out;
7510         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7511         ret = do_chunk_alloc(trans, root, alloc_flags,
7512                              CHUNK_ALLOC_FORCE);
7513         if (ret < 0)
7514                 goto out;
7515         ret = set_block_group_ro(cache, 0);
7516 out:
7517         btrfs_end_transaction(trans, root);
7518         return ret;
7519 }
7520
7521 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7522                             struct btrfs_root *root, u64 type)
7523 {
7524         u64 alloc_flags = get_alloc_profile(root, type);
7525         return do_chunk_alloc(trans, root, alloc_flags,
7526                               CHUNK_ALLOC_FORCE);
7527 }
7528
7529 /*
7530  * helper to account the unused space of all the readonly block group in the
7531  * list. takes mirrors into account.
7532  */
7533 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7534 {
7535         struct btrfs_block_group_cache *block_group;
7536         u64 free_bytes = 0;
7537         int factor;
7538
7539         list_for_each_entry(block_group, groups_list, list) {
7540                 spin_lock(&block_group->lock);
7541
7542                 if (!block_group->ro) {
7543                         spin_unlock(&block_group->lock);
7544                         continue;
7545                 }
7546
7547                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7548                                           BTRFS_BLOCK_GROUP_RAID10 |
7549                                           BTRFS_BLOCK_GROUP_DUP))
7550                         factor = 2;
7551                 else
7552                         factor = 1;
7553
7554                 free_bytes += (block_group->key.offset -
7555                                btrfs_block_group_used(&block_group->item)) *
7556                                factor;
7557
7558                 spin_unlock(&block_group->lock);
7559         }
7560
7561         return free_bytes;
7562 }
7563
7564 /*
7565  * helper to account the unused space of all the readonly block group in the
7566  * space_info. takes mirrors into account.
7567  */
7568 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7569 {
7570         int i;
7571         u64 free_bytes = 0;
7572
7573         spin_lock(&sinfo->lock);
7574
7575         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7576                 if (!list_empty(&sinfo->block_groups[i]))
7577                         free_bytes += __btrfs_get_ro_block_group_free_space(
7578                                                 &sinfo->block_groups[i]);
7579
7580         spin_unlock(&sinfo->lock);
7581
7582         return free_bytes;
7583 }
7584
7585 void btrfs_set_block_group_rw(struct btrfs_root *root,
7586                               struct btrfs_block_group_cache *cache)
7587 {
7588         struct btrfs_space_info *sinfo = cache->space_info;
7589         u64 num_bytes;
7590
7591         BUG_ON(!cache->ro);
7592
7593         spin_lock(&sinfo->lock);
7594         spin_lock(&cache->lock);
7595         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7596                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7597         sinfo->bytes_readonly -= num_bytes;
7598         cache->ro = 0;
7599         spin_unlock(&cache->lock);
7600         spin_unlock(&sinfo->lock);
7601 }
7602
7603 /*
7604  * checks to see if its even possible to relocate this block group.
7605  *
7606  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7607  * ok to go ahead and try.
7608  */
7609 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7610 {
7611         struct btrfs_block_group_cache *block_group;
7612         struct btrfs_space_info *space_info;
7613         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7614         struct btrfs_device *device;
7615         u64 min_free;
7616         u64 dev_min = 1;
7617         u64 dev_nr = 0;
7618         u64 target;
7619         int index;
7620         int full = 0;
7621         int ret = 0;
7622
7623         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7624
7625         /* odd, couldn't find the block group, leave it alone */
7626         if (!block_group)
7627                 return -1;
7628
7629         min_free = btrfs_block_group_used(&block_group->item);
7630
7631         /* no bytes used, we're good */
7632         if (!min_free)
7633                 goto out;
7634
7635         space_info = block_group->space_info;
7636         spin_lock(&space_info->lock);
7637
7638         full = space_info->full;
7639
7640         /*
7641          * if this is the last block group we have in this space, we can't
7642          * relocate it unless we're able to allocate a new chunk below.
7643          *
7644          * Otherwise, we need to make sure we have room in the space to handle
7645          * all of the extents from this block group.  If we can, we're good
7646          */
7647         if ((space_info->total_bytes != block_group->key.offset) &&
7648             (space_info->bytes_used + space_info->bytes_reserved +
7649              space_info->bytes_pinned + space_info->bytes_readonly +
7650              min_free < space_info->total_bytes)) {
7651                 spin_unlock(&space_info->lock);
7652                 goto out;
7653         }
7654         spin_unlock(&space_info->lock);
7655
7656         /*
7657          * ok we don't have enough space, but maybe we have free space on our
7658          * devices to allocate new chunks for relocation, so loop through our
7659          * alloc devices and guess if we have enough space.  if this block
7660          * group is going to be restriped, run checks against the target
7661          * profile instead of the current one.
7662          */
7663         ret = -1;
7664
7665         /*
7666          * index:
7667          *      0: raid10
7668          *      1: raid1
7669          *      2: dup
7670          *      3: raid0
7671          *      4: single
7672          */
7673         target = get_restripe_target(root->fs_info, block_group->flags);
7674         if (target) {
7675                 index = __get_raid_index(extended_to_chunk(target));
7676         } else {
7677                 /*
7678                  * this is just a balance, so if we were marked as full
7679                  * we know there is no space for a new chunk
7680                  */
7681                 if (full)
7682                         goto out;
7683
7684                 index = get_block_group_index(block_group);
7685         }
7686
7687         if (index == BTRFS_RAID_RAID10) {
7688                 dev_min = 4;
7689                 /* Divide by 2 */
7690                 min_free >>= 1;
7691         } else if (index == BTRFS_RAID_RAID1) {
7692                 dev_min = 2;
7693         } else if (index == BTRFS_RAID_DUP) {
7694                 /* Multiply by 2 */
7695                 min_free <<= 1;
7696         } else if (index == BTRFS_RAID_RAID0) {
7697                 dev_min = fs_devices->rw_devices;
7698                 do_div(min_free, dev_min);
7699         }
7700
7701         mutex_lock(&root->fs_info->chunk_mutex);
7702         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7703                 u64 dev_offset;
7704
7705                 /*
7706                  * check to make sure we can actually find a chunk with enough
7707                  * space to fit our block group in.
7708                  */
7709                 if (device->total_bytes > device->bytes_used + min_free &&
7710                     !device->is_tgtdev_for_dev_replace) {
7711                         ret = find_free_dev_extent(device, min_free,
7712                                                    &dev_offset, NULL);
7713                         if (!ret)
7714                                 dev_nr++;
7715
7716                         if (dev_nr >= dev_min)
7717                                 break;
7718
7719                         ret = -1;
7720                 }
7721         }
7722         mutex_unlock(&root->fs_info->chunk_mutex);
7723 out:
7724         btrfs_put_block_group(block_group);
7725         return ret;
7726 }
7727
7728 static int find_first_block_group(struct btrfs_root *root,
7729                 struct btrfs_path *path, struct btrfs_key *key)
7730 {
7731         int ret = 0;
7732         struct btrfs_key found_key;
7733         struct extent_buffer *leaf;
7734         int slot;
7735
7736         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7737         if (ret < 0)
7738                 goto out;
7739
7740         while (1) {
7741                 slot = path->slots[0];
7742                 leaf = path->nodes[0];
7743                 if (slot >= btrfs_header_nritems(leaf)) {
7744                         ret = btrfs_next_leaf(root, path);
7745                         if (ret == 0)
7746                                 continue;
7747                         if (ret < 0)
7748                                 goto out;
7749                         break;
7750                 }
7751                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7752
7753                 if (found_key.objectid >= key->objectid &&
7754                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7755                         ret = 0;
7756                         goto out;
7757                 }
7758                 path->slots[0]++;
7759         }
7760 out:
7761         return ret;
7762 }
7763
7764 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7765 {
7766         struct btrfs_block_group_cache *block_group;
7767         u64 last = 0;
7768
7769         while (1) {
7770                 struct inode *inode;
7771
7772                 block_group = btrfs_lookup_first_block_group(info, last);
7773                 while (block_group) {
7774                         spin_lock(&block_group->lock);
7775                         if (block_group->iref)
7776                                 break;
7777                         spin_unlock(&block_group->lock);
7778                         block_group = next_block_group(info->tree_root,
7779                                                        block_group);
7780                 }
7781                 if (!block_group) {
7782                         if (last == 0)
7783                                 break;
7784                         last = 0;
7785                         continue;
7786                 }
7787
7788                 inode = block_group->inode;
7789                 block_group->iref = 0;
7790                 block_group->inode = NULL;
7791                 spin_unlock(&block_group->lock);
7792                 iput(inode);
7793                 last = block_group->key.objectid + block_group->key.offset;
7794                 btrfs_put_block_group(block_group);
7795         }
7796 }
7797
7798 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7799 {
7800         struct btrfs_block_group_cache *block_group;
7801         struct btrfs_space_info *space_info;
7802         struct btrfs_caching_control *caching_ctl;
7803         struct rb_node *n;
7804
7805         down_write(&info->extent_commit_sem);
7806         while (!list_empty(&info->caching_block_groups)) {
7807                 caching_ctl = list_entry(info->caching_block_groups.next,
7808                                          struct btrfs_caching_control, list);
7809                 list_del(&caching_ctl->list);
7810                 put_caching_control(caching_ctl);
7811         }
7812         up_write(&info->extent_commit_sem);
7813
7814         spin_lock(&info->block_group_cache_lock);
7815         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7816                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7817                                        cache_node);
7818                 rb_erase(&block_group->cache_node,
7819                          &info->block_group_cache_tree);
7820                 spin_unlock(&info->block_group_cache_lock);
7821
7822                 down_write(&block_group->space_info->groups_sem);
7823                 list_del(&block_group->list);
7824                 up_write(&block_group->space_info->groups_sem);
7825
7826                 if (block_group->cached == BTRFS_CACHE_STARTED)
7827                         wait_block_group_cache_done(block_group);
7828
7829                 /*
7830                  * We haven't cached this block group, which means we could
7831                  * possibly have excluded extents on this block group.
7832                  */
7833                 if (block_group->cached == BTRFS_CACHE_NO)
7834                         free_excluded_extents(info->extent_root, block_group);
7835
7836                 btrfs_remove_free_space_cache(block_group);
7837                 btrfs_put_block_group(block_group);
7838
7839                 spin_lock(&info->block_group_cache_lock);
7840         }
7841         spin_unlock(&info->block_group_cache_lock);
7842
7843         /* now that all the block groups are freed, go through and
7844          * free all the space_info structs.  This is only called during
7845          * the final stages of unmount, and so we know nobody is
7846          * using them.  We call synchronize_rcu() once before we start,
7847          * just to be on the safe side.
7848          */
7849         synchronize_rcu();
7850
7851         release_global_block_rsv(info);
7852
7853         while(!list_empty(&info->space_info)) {
7854                 space_info = list_entry(info->space_info.next,
7855                                         struct btrfs_space_info,
7856                                         list);
7857                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
7858                         if (space_info->bytes_pinned > 0 ||
7859                             space_info->bytes_reserved > 0 ||
7860                             space_info->bytes_may_use > 0) {
7861                                 WARN_ON(1);
7862                                 dump_space_info(space_info, 0, 0);
7863                         }
7864                 }
7865                 list_del(&space_info->list);
7866                 kfree(space_info);
7867         }
7868         return 0;
7869 }
7870
7871 static void __link_block_group(struct btrfs_space_info *space_info,
7872                                struct btrfs_block_group_cache *cache)
7873 {
7874         int index = get_block_group_index(cache);
7875
7876         down_write(&space_info->groups_sem);
7877         list_add_tail(&cache->list, &space_info->block_groups[index]);
7878         up_write(&space_info->groups_sem);
7879 }
7880
7881 int btrfs_read_block_groups(struct btrfs_root *root)
7882 {
7883         struct btrfs_path *path;
7884         int ret;
7885         struct btrfs_block_group_cache *cache;
7886         struct btrfs_fs_info *info = root->fs_info;
7887         struct btrfs_space_info *space_info;
7888         struct btrfs_key key;
7889         struct btrfs_key found_key;
7890         struct extent_buffer *leaf;
7891         int need_clear = 0;
7892         u64 cache_gen;
7893
7894         root = info->extent_root;
7895         key.objectid = 0;
7896         key.offset = 0;
7897         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7898         path = btrfs_alloc_path();
7899         if (!path)
7900                 return -ENOMEM;
7901         path->reada = 1;
7902
7903         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
7904         if (btrfs_test_opt(root, SPACE_CACHE) &&
7905             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
7906                 need_clear = 1;
7907         if (btrfs_test_opt(root, CLEAR_CACHE))
7908                 need_clear = 1;
7909
7910         while (1) {
7911                 ret = find_first_block_group(root, path, &key);
7912                 if (ret > 0)
7913                         break;
7914                 if (ret != 0)
7915                         goto error;
7916                 leaf = path->nodes[0];
7917                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7918                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7919                 if (!cache) {
7920                         ret = -ENOMEM;
7921                         goto error;
7922                 }
7923                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7924                                                 GFP_NOFS);
7925                 if (!cache->free_space_ctl) {
7926                         kfree(cache);
7927                         ret = -ENOMEM;
7928                         goto error;
7929                 }
7930
7931                 atomic_set(&cache->count, 1);
7932                 spin_lock_init(&cache->lock);
7933                 cache->fs_info = info;
7934                 INIT_LIST_HEAD(&cache->list);
7935                 INIT_LIST_HEAD(&cache->cluster_list);
7936
7937                 if (need_clear) {
7938                         /*
7939                          * When we mount with old space cache, we need to
7940                          * set BTRFS_DC_CLEAR and set dirty flag.
7941                          *
7942                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
7943                          *    truncate the old free space cache inode and
7944                          *    setup a new one.
7945                          * b) Setting 'dirty flag' makes sure that we flush
7946                          *    the new space cache info onto disk.
7947                          */
7948                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7949                         if (btrfs_test_opt(root, SPACE_CACHE))
7950                                 cache->dirty = 1;
7951                 }
7952
7953                 read_extent_buffer(leaf, &cache->item,
7954                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7955                                    sizeof(cache->item));
7956                 memcpy(&cache->key, &found_key, sizeof(found_key));
7957
7958                 key.objectid = found_key.objectid + found_key.offset;
7959                 btrfs_release_path(path);
7960                 cache->flags = btrfs_block_group_flags(&cache->item);
7961                 cache->sectorsize = root->sectorsize;
7962                 cache->full_stripe_len = btrfs_full_stripe_len(root,
7963                                                &root->fs_info->mapping_tree,
7964                                                found_key.objectid);
7965                 btrfs_init_free_space_ctl(cache);
7966
7967                 /*
7968                  * We need to exclude the super stripes now so that the space
7969                  * info has super bytes accounted for, otherwise we'll think
7970                  * we have more space than we actually do.
7971                  */
7972                 ret = exclude_super_stripes(root, cache);
7973                 if (ret) {
7974                         /*
7975                          * We may have excluded something, so call this just in
7976                          * case.
7977                          */
7978                         free_excluded_extents(root, cache);
7979                         kfree(cache->free_space_ctl);
7980                         kfree(cache);
7981                         goto error;
7982                 }
7983
7984                 /*
7985                  * check for two cases, either we are full, and therefore
7986                  * don't need to bother with the caching work since we won't
7987                  * find any space, or we are empty, and we can just add all
7988                  * the space in and be done with it.  This saves us _alot_ of
7989                  * time, particularly in the full case.
7990                  */
7991                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7992                         cache->last_byte_to_unpin = (u64)-1;
7993                         cache->cached = BTRFS_CACHE_FINISHED;
7994                         free_excluded_extents(root, cache);
7995                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7996                         cache->last_byte_to_unpin = (u64)-1;
7997                         cache->cached = BTRFS_CACHE_FINISHED;
7998                         add_new_free_space(cache, root->fs_info,
7999                                            found_key.objectid,
8000                                            found_key.objectid +
8001                                            found_key.offset);
8002                         free_excluded_extents(root, cache);
8003                 }
8004
8005                 ret = update_space_info(info, cache->flags, found_key.offset,
8006                                         btrfs_block_group_used(&cache->item),
8007                                         &space_info);
8008                 BUG_ON(ret); /* -ENOMEM */
8009                 cache->space_info = space_info;
8010                 spin_lock(&cache->space_info->lock);
8011                 cache->space_info->bytes_readonly += cache->bytes_super;
8012                 spin_unlock(&cache->space_info->lock);
8013
8014                 __link_block_group(space_info, cache);
8015
8016                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8017                 BUG_ON(ret); /* Logic error */
8018
8019                 set_avail_alloc_bits(root->fs_info, cache->flags);
8020                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8021                         set_block_group_ro(cache, 1);
8022         }
8023
8024         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8025                 if (!(get_alloc_profile(root, space_info->flags) &
8026                       (BTRFS_BLOCK_GROUP_RAID10 |
8027                        BTRFS_BLOCK_GROUP_RAID1 |
8028                        BTRFS_BLOCK_GROUP_RAID5 |
8029                        BTRFS_BLOCK_GROUP_RAID6 |
8030                        BTRFS_BLOCK_GROUP_DUP)))
8031                         continue;
8032                 /*
8033                  * avoid allocating from un-mirrored block group if there are
8034                  * mirrored block groups.
8035                  */
8036                 list_for_each_entry(cache, &space_info->block_groups[3], list)
8037                         set_block_group_ro(cache, 1);
8038                 list_for_each_entry(cache, &space_info->block_groups[4], list)
8039                         set_block_group_ro(cache, 1);
8040         }
8041
8042         init_global_block_rsv(info);
8043         ret = 0;
8044 error:
8045         btrfs_free_path(path);
8046         return ret;
8047 }
8048
8049 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
8050                                        struct btrfs_root *root)
8051 {
8052         struct btrfs_block_group_cache *block_group, *tmp;
8053         struct btrfs_root *extent_root = root->fs_info->extent_root;
8054         struct btrfs_block_group_item item;
8055         struct btrfs_key key;
8056         int ret = 0;
8057
8058         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
8059                                  new_bg_list) {
8060                 list_del_init(&block_group->new_bg_list);
8061
8062                 if (ret)
8063                         continue;
8064
8065                 spin_lock(&block_group->lock);
8066                 memcpy(&item, &block_group->item, sizeof(item));
8067                 memcpy(&key, &block_group->key, sizeof(key));
8068                 spin_unlock(&block_group->lock);
8069
8070                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
8071                                         sizeof(item));
8072                 if (ret)
8073                         btrfs_abort_transaction(trans, extent_root, ret);
8074         }
8075 }
8076
8077 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8078                            struct btrfs_root *root, u64 bytes_used,
8079                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8080                            u64 size)
8081 {
8082         int ret;
8083         struct btrfs_root *extent_root;
8084         struct btrfs_block_group_cache *cache;
8085
8086         extent_root = root->fs_info->extent_root;
8087
8088         root->fs_info->last_trans_log_full_commit = trans->transid;
8089
8090         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8091         if (!cache)
8092                 return -ENOMEM;
8093         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8094                                         GFP_NOFS);
8095         if (!cache->free_space_ctl) {
8096                 kfree(cache);
8097                 return -ENOMEM;
8098         }
8099
8100         cache->key.objectid = chunk_offset;
8101         cache->key.offset = size;
8102         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8103         cache->sectorsize = root->sectorsize;
8104         cache->fs_info = root->fs_info;
8105         cache->full_stripe_len = btrfs_full_stripe_len(root,
8106                                                &root->fs_info->mapping_tree,
8107                                                chunk_offset);
8108
8109         atomic_set(&cache->count, 1);
8110         spin_lock_init(&cache->lock);
8111         INIT_LIST_HEAD(&cache->list);
8112         INIT_LIST_HEAD(&cache->cluster_list);
8113         INIT_LIST_HEAD(&cache->new_bg_list);
8114
8115         btrfs_init_free_space_ctl(cache);
8116
8117         btrfs_set_block_group_used(&cache->item, bytes_used);
8118         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8119         cache->flags = type;
8120         btrfs_set_block_group_flags(&cache->item, type);
8121
8122         cache->last_byte_to_unpin = (u64)-1;
8123         cache->cached = BTRFS_CACHE_FINISHED;
8124         ret = exclude_super_stripes(root, cache);
8125         if (ret) {
8126                 /*
8127                  * We may have excluded something, so call this just in
8128                  * case.
8129                  */
8130                 free_excluded_extents(root, cache);
8131                 kfree(cache->free_space_ctl);
8132                 kfree(cache);
8133                 return ret;
8134         }
8135
8136         add_new_free_space(cache, root->fs_info, chunk_offset,
8137                            chunk_offset + size);
8138
8139         free_excluded_extents(root, cache);
8140
8141         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8142                                 &cache->space_info);
8143         BUG_ON(ret); /* -ENOMEM */
8144         update_global_block_rsv(root->fs_info);
8145
8146         spin_lock(&cache->space_info->lock);
8147         cache->space_info->bytes_readonly += cache->bytes_super;
8148         spin_unlock(&cache->space_info->lock);
8149
8150         __link_block_group(cache->space_info, cache);
8151
8152         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8153         BUG_ON(ret); /* Logic error */
8154
8155         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
8156
8157         set_avail_alloc_bits(extent_root->fs_info, type);
8158
8159         return 0;
8160 }
8161
8162 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
8163 {
8164         u64 extra_flags = chunk_to_extended(flags) &
8165                                 BTRFS_EXTENDED_PROFILE_MASK;
8166
8167         write_seqlock(&fs_info->profiles_lock);
8168         if (flags & BTRFS_BLOCK_GROUP_DATA)
8169                 fs_info->avail_data_alloc_bits &= ~extra_flags;
8170         if (flags & BTRFS_BLOCK_GROUP_METADATA)
8171                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
8172         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
8173                 fs_info->avail_system_alloc_bits &= ~extra_flags;
8174         write_sequnlock(&fs_info->profiles_lock);
8175 }
8176
8177 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8178                              struct btrfs_root *root, u64 group_start)
8179 {
8180         struct btrfs_path *path;
8181         struct btrfs_block_group_cache *block_group;
8182         struct btrfs_free_cluster *cluster;
8183         struct btrfs_root *tree_root = root->fs_info->tree_root;
8184         struct btrfs_key key;
8185         struct inode *inode;
8186         int ret;
8187         int index;
8188         int factor;
8189
8190         root = root->fs_info->extent_root;
8191
8192         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8193         BUG_ON(!block_group);
8194         BUG_ON(!block_group->ro);
8195
8196         /*
8197          * Free the reserved super bytes from this block group before
8198          * remove it.
8199          */
8200         free_excluded_extents(root, block_group);
8201
8202         memcpy(&key, &block_group->key, sizeof(key));
8203         index = get_block_group_index(block_group);
8204         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
8205                                   BTRFS_BLOCK_GROUP_RAID1 |
8206                                   BTRFS_BLOCK_GROUP_RAID10))
8207                 factor = 2;
8208         else
8209                 factor = 1;
8210
8211         /* make sure this block group isn't part of an allocation cluster */
8212         cluster = &root->fs_info->data_alloc_cluster;
8213         spin_lock(&cluster->refill_lock);
8214         btrfs_return_cluster_to_free_space(block_group, cluster);
8215         spin_unlock(&cluster->refill_lock);
8216
8217         /*
8218          * make sure this block group isn't part of a metadata
8219          * allocation cluster
8220          */
8221         cluster = &root->fs_info->meta_alloc_cluster;
8222         spin_lock(&cluster->refill_lock);
8223         btrfs_return_cluster_to_free_space(block_group, cluster);
8224         spin_unlock(&cluster->refill_lock);
8225
8226         path = btrfs_alloc_path();
8227         if (!path) {
8228                 ret = -ENOMEM;
8229                 goto out;
8230         }
8231
8232         inode = lookup_free_space_inode(tree_root, block_group, path);
8233         if (!IS_ERR(inode)) {
8234                 ret = btrfs_orphan_add(trans, inode);
8235                 if (ret) {
8236                         btrfs_add_delayed_iput(inode);
8237                         goto out;
8238                 }
8239                 clear_nlink(inode);
8240                 /* One for the block groups ref */
8241                 spin_lock(&block_group->lock);
8242                 if (block_group->iref) {
8243                         block_group->iref = 0;
8244                         block_group->inode = NULL;
8245                         spin_unlock(&block_group->lock);
8246                         iput(inode);
8247                 } else {
8248                         spin_unlock(&block_group->lock);
8249                 }
8250                 /* One for our lookup ref */
8251                 btrfs_add_delayed_iput(inode);
8252         }
8253
8254         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8255         key.offset = block_group->key.objectid;
8256         key.type = 0;
8257
8258         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8259         if (ret < 0)
8260                 goto out;
8261         if (ret > 0)
8262                 btrfs_release_path(path);
8263         if (ret == 0) {
8264                 ret = btrfs_del_item(trans, tree_root, path);
8265                 if (ret)
8266                         goto out;
8267                 btrfs_release_path(path);
8268         }
8269
8270         spin_lock(&root->fs_info->block_group_cache_lock);
8271         rb_erase(&block_group->cache_node,
8272                  &root->fs_info->block_group_cache_tree);
8273
8274         if (root->fs_info->first_logical_byte == block_group->key.objectid)
8275                 root->fs_info->first_logical_byte = (u64)-1;
8276         spin_unlock(&root->fs_info->block_group_cache_lock);
8277
8278         down_write(&block_group->space_info->groups_sem);
8279         /*
8280          * we must use list_del_init so people can check to see if they
8281          * are still on the list after taking the semaphore
8282          */
8283         list_del_init(&block_group->list);
8284         if (list_empty(&block_group->space_info->block_groups[index]))
8285                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8286         up_write(&block_group->space_info->groups_sem);
8287
8288         if (block_group->cached == BTRFS_CACHE_STARTED)
8289                 wait_block_group_cache_done(block_group);
8290
8291         btrfs_remove_free_space_cache(block_group);
8292
8293         spin_lock(&block_group->space_info->lock);
8294         block_group->space_info->total_bytes -= block_group->key.offset;
8295         block_group->space_info->bytes_readonly -= block_group->key.offset;
8296         block_group->space_info->disk_total -= block_group->key.offset * factor;
8297         spin_unlock(&block_group->space_info->lock);
8298
8299         memcpy(&key, &block_group->key, sizeof(key));
8300
8301         btrfs_clear_space_info_full(root->fs_info);
8302
8303         btrfs_put_block_group(block_group);
8304         btrfs_put_block_group(block_group);
8305
8306         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8307         if (ret > 0)
8308                 ret = -EIO;
8309         if (ret < 0)
8310                 goto out;
8311
8312         ret = btrfs_del_item(trans, root, path);
8313 out:
8314         btrfs_free_path(path);
8315         return ret;
8316 }
8317
8318 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8319 {
8320         struct btrfs_space_info *space_info;
8321         struct btrfs_super_block *disk_super;
8322         u64 features;
8323         u64 flags;
8324         int mixed = 0;
8325         int ret;
8326
8327         disk_super = fs_info->super_copy;
8328         if (!btrfs_super_root(disk_super))
8329                 return 1;
8330
8331         features = btrfs_super_incompat_flags(disk_super);
8332         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8333                 mixed = 1;
8334
8335         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8336         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8337         if (ret)
8338                 goto out;
8339
8340         if (mixed) {
8341                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8342                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8343         } else {
8344                 flags = BTRFS_BLOCK_GROUP_METADATA;
8345                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8346                 if (ret)
8347                         goto out;
8348
8349                 flags = BTRFS_BLOCK_GROUP_DATA;
8350                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8351         }
8352 out:
8353         return ret;
8354 }
8355
8356 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8357 {
8358         return unpin_extent_range(root, start, end);
8359 }
8360
8361 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8362                                u64 num_bytes, u64 *actual_bytes)
8363 {
8364         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8365 }
8366
8367 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8368 {
8369         struct btrfs_fs_info *fs_info = root->fs_info;
8370         struct btrfs_block_group_cache *cache = NULL;
8371         u64 group_trimmed;
8372         u64 start;
8373         u64 end;
8374         u64 trimmed = 0;
8375         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8376         int ret = 0;
8377
8378         /*
8379          * try to trim all FS space, our block group may start from non-zero.
8380          */
8381         if (range->len == total_bytes)
8382                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8383         else
8384                 cache = btrfs_lookup_block_group(fs_info, range->start);
8385
8386         while (cache) {
8387                 if (cache->key.objectid >= (range->start + range->len)) {
8388                         btrfs_put_block_group(cache);
8389                         break;
8390                 }
8391
8392                 start = max(range->start, cache->key.objectid);
8393                 end = min(range->start + range->len,
8394                                 cache->key.objectid + cache->key.offset);
8395
8396                 if (end - start >= range->minlen) {
8397                         if (!block_group_cache_done(cache)) {
8398                                 ret = cache_block_group(cache, 0);
8399                                 if (!ret)
8400                                         wait_block_group_cache_done(cache);
8401                         }
8402                         ret = btrfs_trim_block_group(cache,
8403                                                      &group_trimmed,
8404                                                      start,
8405                                                      end,
8406                                                      range->minlen);
8407
8408                         trimmed += group_trimmed;
8409                         if (ret) {
8410                                 btrfs_put_block_group(cache);
8411                                 break;
8412                         }
8413                 }
8414
8415                 cache = next_block_group(fs_info->tree_root, cache);
8416         }
8417
8418         range->len = trimmed;
8419         return ret;
8420 }