Pileus Git - ~andy/linux/blob - fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/percpu_counter.h>
  28 #include "compat.h"
  29 #include "hash.h"
  30 #include "ctree.h"
  31 #include "disk-io.h"
  32 #include "print-tree.h"
  33 #include "transaction.h"
  34 #include "volumes.h"
  35 #include "raid56.h"
  36 #include "locking.h"
  37 #include "free-space-cache.h"
  38 #include "math.h"
  39
  40 #undef SCRAMBLE_DELAYED_REFS
  41
  42 /*
  43  * control flags for do_chunk_alloc's force field
  44  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  45  * if we really need one.
  46  *
  47  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  48  * if we have very few chunks already allocated.  This is
  49  * used as part of the clustering code to help make sure
  50  * we have a good pool of storage to cluster in, without
  51  * filling the FS with empty chunks
  52  *
  53  * CHUNK_ALLOC_FORCE means it must try to allocate one
  54  *
  55  */
  56 enum {
  57         CHUNK_ALLOC_NO_FORCE = 0,
  58         CHUNK_ALLOC_LIMITED = 1,
  59         CHUNK_ALLOC_FORCE = 2,
  60 };
  61
  62 /*
  63  * Control how reservations are dealt with.
  64  *
  65  * RESERVE_FREE - freeing a reservation.
  66  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  67  *   ENOSPC accounting
  68  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  69  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  70  */
  71 enum {
  72         RESERVE_FREE = 0,
  73         RESERVE_ALLOC = 1,
  74         RESERVE_ALLOC_NO_ACCOUNT = 2,
  75 };
  76
  77 static int update_block_group(struct btrfs_root *root,
  78                               u64 bytenr, u64 num_bytes, int alloc);
  79 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  80                                 struct btrfs_root *root,
  81                                 u64 bytenr, u64 num_bytes, u64 parent,
  82                                 u64 root_objectid, u64 owner_objectid,
  83                                 u64 owner_offset, int refs_to_drop,
  84                                 struct btrfs_delayed_extent_op *extra_op);
  85 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  86                                     struct extent_buffer *leaf,
  87                                     struct btrfs_extent_item *ei);
  88 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  89                                       struct btrfs_root *root,
  90                                       u64 parent, u64 root_objectid,
  91                                       u64 flags, u64 owner, u64 offset,
  92                                       struct btrfs_key *ins, int ref_mod);
  93 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  94                                      struct btrfs_root *root,
  95                                      u64 parent, u64 root_objectid,
  96                                      u64 flags, struct btrfs_disk_key *key,
  97                                      int level, struct btrfs_key *ins);
  98 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  99                           struct btrfs_root *extent_root, u64 flags,
 100                           int force);
 101 static int find_next_key(struct btrfs_path *path, int level,
 102                          struct btrfs_key *key);
 103 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 104                             int dump_block_groups);
 105 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 106                                        u64 num_bytes, int reserve);
 107 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 108                                u64 num_bytes);
 109 int btrfs_pin_extent(struct btrfs_root *root,
 110                      u64 bytenr, u64 num_bytes, int reserved);
 111
 112 static noinline int
 113 block_group_cache_done(struct btrfs_block_group_cache *cache)
 114 {
 115         smp_mb();
 116         return cache->cached == BTRFS_CACHE_FINISHED;
 117 }
 118
 119 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 120 {
 121         return (cache->flags & bits) == bits;
 122 }
 123
 124 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 125 {
 126         atomic_inc(&cache->count);
 127 }
 128
 129 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 130 {
 131         if (atomic_dec_and_test(&cache->count)) {
 132                 WARN_ON(cache->pinned > 0);
 133                 WARN_ON(cache->reserved > 0);
 134                 kfree(cache->free_space_ctl);
 135                 kfree(cache);
 136         }
 137 }
 138
 139 /*
 140  * this adds the block group to the fs_info rb tree for the block group
 141  * cache
 142  */
 143 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 144                                 struct btrfs_block_group_cache *block_group)
 145 {
 146         struct rb_node **p;
 147         struct rb_node *parent = NULL;
 148         struct btrfs_block_group_cache *cache;
 149
 150         spin_lock(&info->block_group_cache_lock);
 151         p = &info->block_group_cache_tree.rb_node;
 152
 153         while (*p) {
 154                 parent = *p;
 155                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 156                                  cache_node);
 157                 if (block_group->key.objectid < cache->key.objectid) {
 158                         p = &(*p)->rb_left;
 159                 } else if (block_group->key.objectid > cache->key.objectid) {
 160                         p = &(*p)->rb_right;
 161                 } else {
 162                         spin_unlock(&info->block_group_cache_lock);
 163                         return -EEXIST;
 164                 }
 165         }
 166
 167         rb_link_node(&block_group->cache_node, parent, p);
 168         rb_insert_color(&block_group->cache_node,
 169                         &info->block_group_cache_tree);
 170
 171         if (info->first_logical_byte > block_group->key.objectid)
 172                 info->first_logical_byte = block_group->key.objectid;
 173
 174         spin_unlock(&info->block_group_cache_lock);
 175
 176         return 0;
 177 }
 178
 179 /*
 180  * This will return the block group at or after bytenr if contains is 0, else
 181  * it will return the block group that contains the bytenr
 182  */
 183 static struct btrfs_block_group_cache *
 184 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 185                               int contains)
 186 {
 187         struct btrfs_block_group_cache *cache, *ret = NULL;
 188         struct rb_node *n;
 189         u64 end, start;
 190
 191         spin_lock(&info->block_group_cache_lock);
 192         n = info->block_group_cache_tree.rb_node;
 193
 194         while (n) {
 195                 cache = rb_entry(n, struct btrfs_block_group_cache,
 196                                  cache_node);
 197                 end = cache->key.objectid + cache->key.offset - 1;
 198                 start = cache->key.objectid;
 199
 200                 if (bytenr < start) {
 201                         if (!contains && (!ret || start < ret->key.objectid))
 202                                 ret = cache;
 203                         n = n->rb_left;
 204                 } else if (bytenr > start) {
 205                         if (contains && bytenr <= end) {
 206                                 ret = cache;
 207                                 break;
 208                         }
 209                         n = n->rb_right;
 210                 } else {
 211                         ret = cache;
 212                         break;
 213                 }
 214         }
 215         if (ret) {
 216                 btrfs_get_block_group(ret);
 217                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 218                         info->first_logical_byte = ret->key.objectid;
 219         }
 220         spin_unlock(&info->block_group_cache_lock);
 221
 222         return ret;
 223 }
 224
 225 static int add_excluded_extent(struct btrfs_root *root,
 226                                u64 start, u64 num_bytes)
 227 {
 228         u64 end = start + num_bytes - 1;
 229         set_extent_bits(&root->fs_info->freed_extents[0],
 230                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 231         set_extent_bits(&root->fs_info->freed_extents[1],
 232                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 233         return 0;
 234 }
 235
 236 static void free_excluded_extents(struct btrfs_root *root,
 237                                   struct btrfs_block_group_cache *cache)
 238 {
 239         u64 start, end;
 240
 241         start = cache->key.objectid;
 242         end = start + cache->key.offset - 1;
 243
 244         clear_extent_bits(&root->fs_info->freed_extents[0],
 245                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 246         clear_extent_bits(&root->fs_info->freed_extents[1],
 247                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 248 }
 249
 250 static int exclude_super_stripes(struct btrfs_root *root,
 251                                  struct btrfs_block_group_cache *cache)
 252 {
 253         u64 bytenr;
 254         u64 *logical;
 255         int stripe_len;
 256         int i, nr, ret;
 257
 258         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 259                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 260                 cache->bytes_super += stripe_len;
 261                 ret = add_excluded_extent(root, cache->key.objectid,
 262                                           stripe_len);
 263                 if (ret)
 264                         return ret;
 265         }
 266
 267         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 268                 bytenr = btrfs_sb_offset(i);
 269                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 270                                        cache->key.objectid, bytenr,
 271                                        0, &logical, &nr, &stripe_len);
 272                 if (ret)
 273                         return ret;
 274
 275                 while (nr--) {
 276                         u64 start, len;
 277
 278                         if (logical[nr] > cache->key.objectid +
 279                             cache->key.offset)
 280                                 continue;
 281
 282                         if (logical[nr] + stripe_len <= cache->key.objectid)
 283                                 continue;
 284
 285                         start = logical[nr];
 286                         if (start < cache->key.objectid) {
 287                                 start = cache->key.objectid;
 288                                 len = (logical[nr] + stripe_len) - start;
 289                         } else {
 290                                 len = min_t(u64, stripe_len,
 291                                             cache->key.objectid +
 292                                             cache->key.offset - start);
 293                         }
 294
 295                         cache->bytes_super += len;
 296                         ret = add_excluded_extent(root, start, len);
 297                         if (ret) {
 298                                 kfree(logical);
 299                                 return ret;
 300                         }
 301                 }
 302
 303                 kfree(logical);
 304         }
 305         return 0;
 306 }
 307
 308 static struct btrfs_caching_control *
 309 get_caching_control(struct btrfs_block_group_cache *cache)
 310 {
 311         struct btrfs_caching_control *ctl;
 312
 313         spin_lock(&cache->lock);
 314         if (cache->cached != BTRFS_CACHE_STARTED) {
 315                 spin_unlock(&cache->lock);
 316                 return NULL;
 317         }
 318
 319         /* We're loading it the fast way, so we don't have a caching_ctl. */
 320         if (!cache->caching_ctl) {
 321                 spin_unlock(&cache->lock);
 322                 return NULL;
 323         }
 324
 325         ctl = cache->caching_ctl;
 326         atomic_inc(&ctl->count);
 327         spin_unlock(&cache->lock);
 328         return ctl;
 329 }
 330
 331 static void put_caching_control(struct btrfs_caching_control *ctl)
 332 {
 333         if (atomic_dec_and_test(&ctl->count))
 334                 kfree(ctl);
 335 }
 336
 337 /*
 338  * this is only called by cache_block_group, since we could have freed extents
 339  * we need to check the pinned_extents for any extents that can't be used yet
 340  * since their free space will be released as soon as the transaction commits.
 341  */
 342 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 343                               struct btrfs_fs_info *info, u64 start, u64 end)
 344 {
 345         u64 extent_start, extent_end, size, total_added = 0;
 346         int ret;
 347
 348         while (start < end) {
 349                 ret = find_first_extent_bit(info->pinned_extents, start,
 350                                             &extent_start, &extent_end,
 351                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 352                                             NULL);
 353                 if (ret)
 354                         break;
 355
 356                 if (extent_start <= start) {
 357                         start = extent_end + 1;
 358                 } else if (extent_start > start && extent_start < end) {
 359                         size = extent_start - start;
 360                         total_added += size;
 361                         ret = btrfs_add_free_space(block_group, start,
 362                                                    size);
 363                         BUG_ON(ret); /* -ENOMEM or logic error */
 364                         start = extent_end + 1;
 365                 } else {
 366                         break;
 367                 }
 368         }
 369
 370         if (start < end) {
 371                 size = end - start;
 372                 total_added += size;
 373                 ret = btrfs_add_free_space(block_group, start, size);
 374                 BUG_ON(ret); /* -ENOMEM or logic error */
 375         }
 376
 377         return total_added;
 378 }
 379
 380 static noinline void caching_thread(struct btrfs_work *work)
 381 {
 382         struct btrfs_block_group_cache *block_group;
 383         struct btrfs_fs_info *fs_info;
 384         struct btrfs_caching_control *caching_ctl;
 385         struct btrfs_root *extent_root;
 386         struct btrfs_path *path;
 387         struct extent_buffer *leaf;
 388         struct btrfs_key key;
 389         u64 total_found = 0;
 390         u64 last = 0;
 391         u32 nritems;
 392         int ret = 0;
 393
 394         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 395         block_group = caching_ctl->block_group;
 396         fs_info = block_group->fs_info;
 397         extent_root = fs_info->extent_root;
 398
 399         path = btrfs_alloc_path();
 400         if (!path)
 401                 goto out;
 402
 403         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 404
 405         /*
 406          * We don't want to deadlock with somebody trying to allocate a new
 407          * extent for the extent root while also trying to search the extent
 408          * root to add free space.  So we skip locking and search the commit
 409          * root, since its read-only
 410          */
 411         path->skip_locking = 1;
 412         path->search_commit_root = 1;
 413         path->reada = 1;
 414
 415         key.objectid = last;
 416         key.offset = 0;
 417         key.type = BTRFS_EXTENT_ITEM_KEY;
 418 again:
 419         mutex_lock(&caching_ctl->mutex);
 420         /* need to make sure the commit_root doesn't disappear */
 421         down_read(&fs_info->extent_commit_sem);
 422
 423         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 424         if (ret < 0)
 425                 goto err;
 426
 427         leaf = path->nodes[0];
 428         nritems = btrfs_header_nritems(leaf);
 429
 430         while (1) {
 431                 if (btrfs_fs_closing(fs_info) > 1) {
 432                         last = (u64)-1;
 433                         break;
 434                 }
 435
 436                 if (path->slots[0] < nritems) {
 437                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 438                 } else {
 439                         ret = find_next_key(path, 0, &key);
 440                         if (ret)
 441                                 break;
 442
 443                         if (need_resched()) {
 444                                 caching_ctl->progress = last;
 445                                 btrfs_release_path(path);
 446                                 up_read(&fs_info->extent_commit_sem);
 447                                 mutex_unlock(&caching_ctl->mutex);
 448                                 cond_resched();
 449                                 goto again;
 450                         }
 451
 452                         ret = btrfs_next_leaf(extent_root, path);
 453                         if (ret < 0)
 454                                 goto err;
 455                         if (ret)
 456                                 break;
 457                         leaf = path->nodes[0];
 458                         nritems = btrfs_header_nritems(leaf);
 459                         continue;
 460                 }
 461
 462                 if (key.objectid < block_group->key.objectid) {
 463                         path->slots[0]++;
 464                         continue;
 465                 }
 466
 467                 if (key.objectid >= block_group->key.objectid +
 468                     block_group->key.offset)
 469                         break;
 470
 471                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 472                     key.type == BTRFS_METADATA_ITEM_KEY) {
 473                         total_found += add_new_free_space(block_group,
 474                                                           fs_info, last,
 475                                                           key.objectid);
 476                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 477                                 last = key.objectid +
 478                                         fs_info->tree_root->leafsize;
 479                         else
 480                                 last = key.objectid + key.offset;
 481
 482                         if (total_found > (1024 * 1024 * 2)) {
 483                                 total_found = 0;
 484                                 wake_up(&caching_ctl->wait);
 485                         }
 486                 }
 487                 path->slots[0]++;
 488         }
 489         ret = 0;
 490
 491         total_found += add_new_free_space(block_group, fs_info, last,
 492                                           block_group->key.objectid +
 493                                           block_group->key.offset);
 494         caching_ctl->progress = (u64)-1;
 495
 496         spin_lock(&block_group->lock);
 497         block_group->caching_ctl = NULL;
 498         block_group->cached = BTRFS_CACHE_FINISHED;
 499         spin_unlock(&block_group->lock);
 500
 501 err:
 502         btrfs_free_path(path);
 503         up_read(&fs_info->extent_commit_sem);
 504
 505         free_excluded_extents(extent_root, block_group);
 506
 507         mutex_unlock(&caching_ctl->mutex);
 508 out:
 509         wake_up(&caching_ctl->wait);
 510
 511         put_caching_control(caching_ctl);
 512         btrfs_put_block_group(block_group);
 513 }
 514
 515 static int cache_block_group(struct btrfs_block_group_cache *cache,
 516                              int load_cache_only)
 517 {
 518         DEFINE_WAIT(wait);
 519         struct btrfs_fs_info *fs_info = cache->fs_info;
 520         struct btrfs_caching_control *caching_ctl;
 521         int ret = 0;
 522
 523         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 524         if (!caching_ctl)
 525                 return -ENOMEM;
 526
 527         INIT_LIST_HEAD(&caching_ctl->list);
 528         mutex_init(&caching_ctl->mutex);
 529         init_waitqueue_head(&caching_ctl->wait);
 530         caching_ctl->block_group = cache;
 531         caching_ctl->progress = cache->key.objectid;
 532         atomic_set(&caching_ctl->count, 1);
 533         caching_ctl->work.func = caching_thread;
 534
 535         spin_lock(&cache->lock);
 536         /*
 537          * This should be a rare occasion, but this could happen I think in the
 538          * case where one thread starts to load the space cache info, and then
 539          * some other thread starts a transaction commit which tries to do an
 540          * allocation while the other thread is still loading the space cache
 541          * info.  The previous loop should have kept us from choosing this block
 542          * group, but if we've moved to the state where we will wait on caching
 543          * block groups we need to first check if we're doing a fast load here,
 544          * so we can wait for it to finish, otherwise we could end up allocating
 545          * from a block group who's cache gets evicted for one reason or
 546          * another.
 547          */
 548         while (cache->cached == BTRFS_CACHE_FAST) {
 549                 struct btrfs_caching_control *ctl;
 550
 551                 ctl = cache->caching_ctl;
 552                 atomic_inc(&ctl->count);
 553                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 554                 spin_unlock(&cache->lock);
 555
 556                 schedule();
 557
 558                 finish_wait(&ctl->wait, &wait);
 559                 put_caching_control(ctl);
 560                 spin_lock(&cache->lock);
 561         }
 562
 563         if (cache->cached != BTRFS_CACHE_NO) {
 564                 spin_unlock(&cache->lock);
 565                 kfree(caching_ctl);
 566                 return 0;
 567         }
 568         WARN_ON(cache->caching_ctl);
 569         cache->caching_ctl = caching_ctl;
 570         cache->cached = BTRFS_CACHE_FAST;
 571         spin_unlock(&cache->lock);
 572
 573         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 574                 ret = load_free_space_cache(fs_info, cache);
 575
 576                 spin_lock(&cache->lock);
 577                 if (ret == 1) {
 578                         cache->caching_ctl = NULL;
 579                         cache->cached = BTRFS_CACHE_FINISHED;
 580                         cache->last_byte_to_unpin = (u64)-1;
 581                 } else {
 582                         if (load_cache_only) {
 583                                 cache->caching_ctl = NULL;
 584                                 cache->cached = BTRFS_CACHE_NO;
 585                         } else {
 586                                 cache->cached = BTRFS_CACHE_STARTED;
 587                         }
 588                 }
 589                 spin_unlock(&cache->lock);
 590                 wake_up(&caching_ctl->wait);
 591                 if (ret == 1) {
 592                         put_caching_control(caching_ctl);
 593                         free_excluded_extents(fs_info->extent_root, cache);
 594                         return 0;
 595                 }
 596         } else {
 597                 /*
 598                  * We are not going to do the fast caching, set cached to the
 599                  * appropriate value and wakeup any waiters.
 600                  */
 601                 spin_lock(&cache->lock);
 602                 if (load_cache_only) {
 603                         cache->caching_ctl = NULL;
 604                         cache->cached = BTRFS_CACHE_NO;
 605                 } else {
 606                         cache->cached = BTRFS_CACHE_STARTED;
 607                 }
 608                 spin_unlock(&cache->lock);
 609                 wake_up(&caching_ctl->wait);
 610         }
 611
 612         if (load_cache_only) {
 613                 put_caching_control(caching_ctl);
 614                 return 0;
 615         }
 616
 617         down_write(&fs_info->extent_commit_sem);
 618         atomic_inc(&caching_ctl->count);
 619         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 620         up_write(&fs_info->extent_commit_sem);
 621
 622         btrfs_get_block_group(cache);
 623
 624         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 625
 626         return ret;
 627 }
 628
 629 /*
 630  * return the block group that starts at or after bytenr
 631  */
 632 static struct btrfs_block_group_cache *
 633 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 634 {
 635         struct btrfs_block_group_cache *cache;
 636
 637         cache = block_group_cache_tree_search(info, bytenr, 0);
 638
 639         return cache;
 640 }
 641
 642 /*
 643  * return the block group that contains the given bytenr
 644  */
 645 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 646                                                  struct btrfs_fs_info *info,
 647                                                  u64 bytenr)
 648 {
 649         struct btrfs_block_group_cache *cache;
 650
 651         cache = block_group_cache_tree_search(info, bytenr, 1);
 652
 653         return cache;
 654 }
 655
 656 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 657                                                   u64 flags)
 658 {
 659         struct list_head *head = &info->space_info;
 660         struct btrfs_space_info *found;
 661
 662         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 663
 664         rcu_read_lock();
 665         list_for_each_entry_rcu(found, head, list) {
 666                 if (found->flags & flags) {
 667                         rcu_read_unlock();
 668                         return found;
 669                 }
 670         }
 671         rcu_read_unlock();
 672         return NULL;
 673 }
 674
 675 /*
 676  * after adding space to the filesystem, we need to clear the full flags
 677  * on all the space infos.
 678  */
 679 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 680 {
 681         struct list_head *head = &info->space_info;
 682         struct btrfs_space_info *found;
 683
 684         rcu_read_lock();
 685         list_for_each_entry_rcu(found, head, list)
 686                 found->full = 0;
 687         rcu_read_unlock();
 688 }
 689
 690 /* simple helper to search for an existing extent at a given offset */
 691 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 692 {
 693         int ret;
 694         struct btrfs_key key;
 695         struct btrfs_path *path;
 696
 697         path = btrfs_alloc_path();
 698         if (!path)
 699                 return -ENOMEM;
 700
 701         key.objectid = start;
 702         key.offset = len;
 703         key.type = BTRFS_EXTENT_ITEM_KEY;
 704         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 705                                 0, 0);
 706         if (ret > 0) {
 707                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 708                 if (key.objectid == start &&
 709                     key.type == BTRFS_METADATA_ITEM_KEY)
 710                         ret = 0;
 711         }
 712         btrfs_free_path(path);
 713         return ret;
 714 }
 715
 716 /*
 717  * helper function to lookup reference count and flags of a tree block.
 718  *
 719  * the head node for delayed ref is used to store the sum of all the
 720  * reference count modifications queued up in the rbtree. the head
 721  * node may also store the extent flags to set. This way you can check
 722  * to see what the reference count and extent flags would be if all of
 723  * the delayed refs are not processed.
 724  */
 725 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 726                              struct btrfs_root *root, u64 bytenr,
 727                              u64 offset, int metadata, u64 *refs, u64 *flags)
 728 {
 729         struct btrfs_delayed_ref_head *head;
 730         struct btrfs_delayed_ref_root *delayed_refs;
 731         struct btrfs_path *path;
 732         struct btrfs_extent_item *ei;
 733         struct extent_buffer *leaf;
 734         struct btrfs_key key;
 735         u32 item_size;
 736         u64 num_refs;
 737         u64 extent_flags;
 738         int ret;
 739
 740         /*
 741          * If we don't have skinny metadata, don't bother doing anything
 742          * different
 743          */
 744         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 745                 offset = root->leafsize;
 746                 metadata = 0;
 747         }
 748
 749         path = btrfs_alloc_path();
 750         if (!path)
 751                 return -ENOMEM;
 752
 753         if (metadata) {
 754                 key.objectid = bytenr;
 755                 key.type = BTRFS_METADATA_ITEM_KEY;
 756                 key.offset = offset;
 757         } else {
 758                 key.objectid = bytenr;
 759                 key.type = BTRFS_EXTENT_ITEM_KEY;
 760                 key.offset = offset;
 761         }
 762
 763         if (!trans) {
 764                 path->skip_locking = 1;
 765                 path->search_commit_root = 1;
 766         }
 767 again:
 768         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 769                                 &key, path, 0, 0);
 770         if (ret < 0)
 771                 goto out_free;
 772
 773         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 774                 key.type = BTRFS_EXTENT_ITEM_KEY;
 775                 key.offset = root->leafsize;
 776                 btrfs_release_path(path);
 777                 goto again;
 778         }
 779
 780         if (ret == 0) {
 781                 leaf = path->nodes[0];
 782                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 783                 if (item_size >= sizeof(*ei)) {
 784                         ei = btrfs_item_ptr(leaf, path->slots[0],
 785                                             struct btrfs_extent_item);
 786                         num_refs = btrfs_extent_refs(leaf, ei);
 787                         extent_flags = btrfs_extent_flags(leaf, ei);
 788                 } else {
 789 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 790                         struct btrfs_extent_item_v0 *ei0;
 791                         BUG_ON(item_size != sizeof(*ei0));
 792                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 793                                              struct btrfs_extent_item_v0);
 794                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 795                         /* FIXME: this isn't correct for data */
 796                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 797 #else
 798                         BUG();
 799 #endif
 800                 }
 801                 BUG_ON(num_refs == 0);
 802         } else {
 803                 num_refs = 0;
 804                 extent_flags = 0;
 805                 ret = 0;
 806         }
 807
 808         if (!trans)
 809                 goto out;
 810
 811         delayed_refs = &trans->transaction->delayed_refs;
 812         spin_lock(&delayed_refs->lock);
 813         head = btrfs_find_delayed_ref_head(trans, bytenr);
 814         if (head) {
 815                 if (!mutex_trylock(&head->mutex)) {
 816                         atomic_inc(&head->node.refs);
 817                         spin_unlock(&delayed_refs->lock);
 818
 819                         btrfs_release_path(path);
 820
 821                         /*
 822                          * Mutex was contended, block until it's released and try
 823                          * again
 824                          */
 825                         mutex_lock(&head->mutex);
 826                         mutex_unlock(&head->mutex);
 827                         btrfs_put_delayed_ref(&head->node);
 828                         goto again;
 829                 }
 830                 if (head->extent_op && head->extent_op->update_flags)
 831                         extent_flags |= head->extent_op->flags_to_set;
 832                 else
 833                         BUG_ON(num_refs == 0);
 834
 835                 num_refs += head->node.ref_mod;
 836                 mutex_unlock(&head->mutex);
 837         }
 838         spin_unlock(&delayed_refs->lock);
 839 out:
 840         WARN_ON(num_refs == 0);
 841         if (refs)
 842                 *refs = num_refs;
 843         if (flags)
 844                 *flags = extent_flags;
 845 out_free:
 846         btrfs_free_path(path);
 847         return ret;
 848 }
 849
 850 /*
 851  * Back reference rules.  Back refs have three main goals:
 852  *
 853  * 1) differentiate between all holders of references to an extent so that
 854  *    when a reference is dropped we can make sure it was a valid reference
 855  *    before freeing the extent.
 856  *
 857  * 2) Provide enough information to quickly find the holders of an extent
 858  *    if we notice a given block is corrupted or bad.
 859  *
 860  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 861  *    maintenance.  This is actually the same as #2, but with a slightly
 862  *    different use case.
 863  *
 864  * There are two kinds of back refs. The implicit back refs is optimized
 865  * for pointers in non-shared tree blocks. For a given pointer in a block,
 866  * back refs of this kind provide information about the block's owner tree
 867  * and the pointer's key. These information allow us to find the block by
 868  * b-tree searching. The full back refs is for pointers in tree blocks not
 869  * referenced by their owner trees. The location of tree block is recorded
 870  * in the back refs. Actually the full back refs is generic, and can be
 871  * used in all cases the implicit back refs is used. The major shortcoming
 872  * of the full back refs is its overhead. Every time a tree block gets
 873  * COWed, we have to update back refs entry for all pointers in it.
 874  *
 875  * For a newly allocated tree block, we use implicit back refs for
 876  * pointers in it. This means most tree related operations only involve
 877  * implicit back refs. For a tree block created in old transaction, the
 878  * only way to drop a reference to it is COW it. So we can detect the
 879  * event that tree block loses its owner tree's reference and do the
 880  * back refs conversion.
 881  *
 882  * When a tree block is COW'd through a tree, there are four cases:
 883  *
 884  * The reference count of the block is one and the tree is the block's
 885  * owner tree. Nothing to do in this case.
 886  *
 887  * The reference count of the block is one and the tree is not the
 888  * block's owner tree. In this case, full back refs is used for pointers
 889  * in the block. Remove these full back refs, add implicit back refs for
 890  * every pointers in the new block.
 891  *
 892  * The reference count of the block is greater than one and the tree is
 893  * the block's owner tree. In this case, implicit back refs is used for
 894  * pointers in the block. Add full back refs for every pointers in the
 895  * block, increase lower level extents' reference counts. The original
 896  * implicit back refs are entailed to the new block.
 897  *
 898  * The reference count of the block is greater than one and the tree is
 899  * not the block's owner tree. Add implicit back refs for every pointer in
 900  * the new block, increase lower level extents' reference count.
 901  *
 902  * Back Reference Key composing:
 903  *
 904  * The key objectid corresponds to the first byte in the extent,
 905  * The key type is used to differentiate between types of back refs.
 906  * There are different meanings of the key offset for different types
 907  * of back refs.
 908  *
 909  * File extents can be referenced by:
 910  *
 911  * - multiple snapshots, subvolumes, or different generations in one subvol
 912  * - different files inside a single subvolume
 913  * - different offsets inside a file (bookend extents in file.c)
 914  *
 915  * The extent ref structure for the implicit back refs has fields for:
 916  *
 917  * - Objectid of the subvolume root
 918  * - objectid of the file holding the reference
 919  * - original offset in the file
 920  * - how many bookend extents
 921  *
 922  * The key offset for the implicit back refs is hash of the first
 923  * three fields.
 924  *
 925  * The extent ref structure for the full back refs has field for:
 926  *
 927  * - number of pointers in the tree leaf
 928  *
 929  * The key offset for the implicit back refs is the first byte of
 930  * the tree leaf
 931  *
 932  * When a file extent is allocated, The implicit back refs is used.
 933  * the fields are filled in:
 934  *
 935  *     (root_key.objectid, inode objectid, offset in file, 1)
 936  *
 937  * When a file extent is removed file truncation, we find the
 938  * corresponding implicit back refs and check the following fields:
 939  *
 940  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 941  *
 942  * Btree extents can be referenced by:
 943  *
 944  * - Different subvolumes
 945  *
 946  * Both the implicit back refs and the full back refs for tree blocks
 947  * only consist of key. The key offset for the implicit back refs is
 948  * objectid of block's owner tree. The key offset for the full back refs
 949  * is the first byte of parent block.
 950  *
 951  * When implicit back refs is used, information about the lowest key and
 952  * level of the tree block are required. These information are stored in
 953  * tree block info structure.
 954  */
 955
 956 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 957 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 958                                   struct btrfs_root *root,
 959                                   struct btrfs_path *path,
 960                                   u64 owner, u32 extra_size)
 961 {
 962         struct btrfs_extent_item *item;
 963         struct btrfs_extent_item_v0 *ei0;
 964         struct btrfs_extent_ref_v0 *ref0;
 965         struct btrfs_tree_block_info *bi;
 966         struct extent_buffer *leaf;
 967         struct btrfs_key key;
 968         struct btrfs_key found_key;
 969         u32 new_size = sizeof(*item);
 970         u64 refs;
 971         int ret;
 972
 973         leaf = path->nodes[0];
 974         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 975
 976         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 977         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 978                              struct btrfs_extent_item_v0);
 979         refs = btrfs_extent_refs_v0(leaf, ei0);
 980
 981         if (owner == (u64)-1) {
 982                 while (1) {
 983                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 984                                 ret = btrfs_next_leaf(root, path);
 985                                 if (ret < 0)
 986                                         return ret;
 987                                 BUG_ON(ret > 0); /* Corruption */
 988                                 leaf = path->nodes[0];
 989                         }
 990                         btrfs_item_key_to_cpu(leaf, &found_key,
 991                                               path->slots[0]);
 992                         BUG_ON(key.objectid != found_key.objectid);
 993                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 994                                 path->slots[0]++;
 995                                 continue;
 996                         }
 997                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 998                                               struct btrfs_extent_ref_v0);
 999                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1000                         break;
1001                 }
1002         }
1003         btrfs_release_path(path);
1004
1005         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1006                 new_size += sizeof(*bi);
1007
1008         new_size -= sizeof(*ei0);
1009         ret = btrfs_search_slot(trans, root, &key, path,
1010                                 new_size + extra_size, 1);
1011         if (ret < 0)
1012                 return ret;
1013         BUG_ON(ret); /* Corruption */
1014
1015         btrfs_extend_item(root, path, new_size);
1016
1017         leaf = path->nodes[0];
1018         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1019         btrfs_set_extent_refs(leaf, item, refs);
1020         /* FIXME: get real generation */
1021         btrfs_set_extent_generation(leaf, item, 0);
1022         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1023                 btrfs_set_extent_flags(leaf, item,
1024                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1025                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1026                 bi = (struct btrfs_tree_block_info *)(item + 1);
1027                 /* FIXME: get first key of the block */
1028                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1029                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1030         } else {
1031                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1032         }
1033         btrfs_mark_buffer_dirty(leaf);
1034         return 0;
1035 }
1036 #endif
1037
1038 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1039 {
1040         u32 high_crc = ~(u32)0;
1041         u32 low_crc = ~(u32)0;
1042         __le64 lenum;
1043
1044         lenum = cpu_to_le64(root_objectid);
1045         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1046         lenum = cpu_to_le64(owner);
1047         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1048         lenum = cpu_to_le64(offset);
1049         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1050
1051         return ((u64)high_crc << 31) ^ (u64)low_crc;
1052 }
1053
1054 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1055                                      struct btrfs_extent_data_ref *ref)
1056 {
1057         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1058                                     btrfs_extent_data_ref_objectid(leaf, ref),
1059                                     btrfs_extent_data_ref_offset(leaf, ref));
1060 }
1061
1062 static int match_extent_data_ref(struct extent_buffer *leaf,
1063                                  struct btrfs_extent_data_ref *ref,
1064                                  u64 root_objectid, u64 owner, u64 offset)
1065 {
1066         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1067             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1068             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1069                 return 0;
1070         return 1;
1071 }
1072
1073 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1074                                            struct btrfs_root *root,
1075                                            struct btrfs_path *path,
1076                                            u64 bytenr, u64 parent,
1077                                            u64 root_objectid,
1078                                            u64 owner, u64 offset)
1079 {
1080         struct btrfs_key key;
1081         struct btrfs_extent_data_ref *ref;
1082         struct extent_buffer *leaf;
1083         u32 nritems;
1084         int ret;
1085         int recow;
1086         int err = -ENOENT;
1087
1088         key.objectid = bytenr;
1089         if (parent) {
1090                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1091                 key.offset = parent;
1092         } else {
1093                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1094                 key.offset = hash_extent_data_ref(root_objectid,
1095                                                   owner, offset);
1096         }
1097 again:
1098         recow = 0;
1099         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1100         if (ret < 0) {
1101                 err = ret;
1102                 goto fail;
1103         }
1104
1105         if (parent) {
1106                 if (!ret)
1107                         return 0;
1108 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1109                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1110                 btrfs_release_path(path);
1111                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1112                 if (ret < 0) {
1113                         err = ret;
1114                         goto fail;
1115                 }
1116                 if (!ret)
1117                         return 0;
1118 #endif
1119                 goto fail;
1120         }
1121
1122         leaf = path->nodes[0];
1123         nritems = btrfs_header_nritems(leaf);
1124         while (1) {
1125                 if (path->slots[0] >= nritems) {
1126                         ret = btrfs_next_leaf(root, path);
1127                         if (ret < 0)
1128                                 err = ret;
1129                         if (ret)
1130                                 goto fail;
1131
1132                         leaf = path->nodes[0];
1133                         nritems = btrfs_header_nritems(leaf);
1134                         recow = 1;
1135                 }
1136
1137                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1138                 if (key.objectid != bytenr ||
1139                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1140                         goto fail;
1141
1142                 ref = btrfs_item_ptr(leaf, path->slots[0],
1143                                      struct btrfs_extent_data_ref);
1144
1145                 if (match_extent_data_ref(leaf, ref, root_objectid,
1146                                           owner, offset)) {
1147                         if (recow) {
1148                                 btrfs_release_path(path);
1149                                 goto again;
1150                         }
1151                         err = 0;
1152                         break;
1153                 }
1154                 path->slots[0]++;
1155         }
1156 fail:
1157         return err;
1158 }
1159
1160 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1161                                            struct btrfs_root *root,
1162                                            struct btrfs_path *path,
1163                                            u64 bytenr, u64 parent,
1164                                            u64 root_objectid, u64 owner,
1165                                            u64 offset, int refs_to_add)
1166 {
1167         struct btrfs_key key;
1168         struct extent_buffer *leaf;
1169         u32 size;
1170         u32 num_refs;
1171         int ret;
1172
1173         key.objectid = bytenr;
1174         if (parent) {
1175                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1176                 key.offset = parent;
1177                 size = sizeof(struct btrfs_shared_data_ref);
1178         } else {
1179                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1180                 key.offset = hash_extent_data_ref(root_objectid,
1181                                                   owner, offset);
1182                 size = sizeof(struct btrfs_extent_data_ref);
1183         }
1184
1185         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1186         if (ret && ret != -EEXIST)
1187                 goto fail;
1188
1189         leaf = path->nodes[0];
1190         if (parent) {
1191                 struct btrfs_shared_data_ref *ref;
1192                 ref = btrfs_item_ptr(leaf, path->slots[0],
1193                                      struct btrfs_shared_data_ref);
1194                 if (ret == 0) {
1195                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1196                 } else {
1197                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1198                         num_refs += refs_to_add;
1199                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1200                 }
1201         } else {
1202                 struct btrfs_extent_data_ref *ref;
1203                 while (ret == -EEXIST) {
1204                         ref = btrfs_item_ptr(leaf, path->slots[0],
1205                                              struct btrfs_extent_data_ref);
1206                         if (match_extent_data_ref(leaf, ref, root_objectid,
1207                                                   owner, offset))
1208                                 break;
1209                         btrfs_release_path(path);
1210                         key.offset++;
1211                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1212                                                       size);
1213                         if (ret && ret != -EEXIST)
1214                                 goto fail;
1215
1216                         leaf = path->nodes[0];
1217                 }
1218                 ref = btrfs_item_ptr(leaf, path->slots[0],
1219                                      struct btrfs_extent_data_ref);
1220                 if (ret == 0) {
1221                         btrfs_set_extent_data_ref_root(leaf, ref,
1222                                                        root_objectid);
1223                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1224                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1225                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1226                 } else {
1227                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1228                         num_refs += refs_to_add;
1229                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1230                 }
1231         }
1232         btrfs_mark_buffer_dirty(leaf);
1233         ret = 0;
1234 fail:
1235         btrfs_release_path(path);
1236         return ret;
1237 }
1238
1239 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1240                                            struct btrfs_root *root,
1241                                            struct btrfs_path *path,
1242                                            int refs_to_drop)
1243 {
1244         struct btrfs_key key;
1245         struct btrfs_extent_data_ref *ref1 = NULL;
1246         struct btrfs_shared_data_ref *ref2 = NULL;
1247         struct extent_buffer *leaf;
1248         u32 num_refs = 0;
1249         int ret = 0;
1250
1251         leaf = path->nodes[0];
1252         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1253
1254         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1255                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1256                                       struct btrfs_extent_data_ref);
1257                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1258         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1259                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1260                                       struct btrfs_shared_data_ref);
1261                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1262 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1263         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1264                 struct btrfs_extent_ref_v0 *ref0;
1265                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1266                                       struct btrfs_extent_ref_v0);
1267                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1268 #endif
1269         } else {
1270                 BUG();
1271         }
1272
1273         BUG_ON(num_refs < refs_to_drop);
1274         num_refs -= refs_to_drop;
1275
1276         if (num_refs == 0) {
1277                 ret = btrfs_del_item(trans, root, path);
1278         } else {
1279                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1280                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1281                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1282                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1283 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1284                 else {
1285                         struct btrfs_extent_ref_v0 *ref0;
1286                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1287                                         struct btrfs_extent_ref_v0);
1288                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1289                 }
1290 #endif
1291                 btrfs_mark_buffer_dirty(leaf);
1292         }
1293         return ret;
1294 }
1295
1296 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1297                                           struct btrfs_path *path,
1298                                           struct btrfs_extent_inline_ref *iref)
1299 {
1300         struct btrfs_key key;
1301         struct extent_buffer *leaf;
1302         struct btrfs_extent_data_ref *ref1;
1303         struct btrfs_shared_data_ref *ref2;
1304         u32 num_refs = 0;
1305
1306         leaf = path->nodes[0];
1307         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1308         if (iref) {
1309                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1310                     BTRFS_EXTENT_DATA_REF_KEY) {
1311                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1312                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1313                 } else {
1314                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1315                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1316                 }
1317         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1318                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1319                                       struct btrfs_extent_data_ref);
1320                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1321         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1322                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1323                                       struct btrfs_shared_data_ref);
1324                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1325 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1326         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1327                 struct btrfs_extent_ref_v0 *ref0;
1328                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1329                                       struct btrfs_extent_ref_v0);
1330                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1331 #endif
1332         } else {
1333                 WARN_ON(1);
1334         }
1335         return num_refs;
1336 }
1337
1338 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1339                                           struct btrfs_root *root,
1340                                           struct btrfs_path *path,
1341                                           u64 bytenr, u64 parent,
1342                                           u64 root_objectid)
1343 {
1344         struct btrfs_key key;
1345         int ret;
1346
1347         key.objectid = bytenr;
1348         if (parent) {
1349                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1350                 key.offset = parent;
1351         } else {
1352                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1353                 key.offset = root_objectid;
1354         }
1355
1356         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1357         if (ret > 0)
1358                 ret = -ENOENT;
1359 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1360         if (ret == -ENOENT && parent) {
1361                 btrfs_release_path(path);
1362                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1363                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1364                 if (ret > 0)
1365                         ret = -ENOENT;
1366         }
1367 #endif
1368         return ret;
1369 }
1370
1371 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1372                                           struct btrfs_root *root,
1373                                           struct btrfs_path *path,
1374                                           u64 bytenr, u64 parent,
1375                                           u64 root_objectid)
1376 {
1377         struct btrfs_key key;
1378         int ret;
1379
1380         key.objectid = bytenr;
1381         if (parent) {
1382                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1383                 key.offset = parent;
1384         } else {
1385                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1386                 key.offset = root_objectid;
1387         }
1388
1389         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1390         btrfs_release_path(path);
1391         return ret;
1392 }
1393
1394 static inline int extent_ref_type(u64 parent, u64 owner)
1395 {
1396         int type;
1397         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1398                 if (parent > 0)
1399                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1400                 else
1401                         type = BTRFS_TREE_BLOCK_REF_KEY;
1402         } else {
1403                 if (parent > 0)
1404                         type = BTRFS_SHARED_DATA_REF_KEY;
1405                 else
1406                         type = BTRFS_EXTENT_DATA_REF_KEY;
1407         }
1408         return type;
1409 }
1410
1411 static int find_next_key(struct btrfs_path *path, int level,
1412                          struct btrfs_key *key)
1413
1414 {
1415         for (; level < BTRFS_MAX_LEVEL; level++) {
1416                 if (!path->nodes[level])
1417                         break;
1418                 if (path->slots[level] + 1 >=
1419                     btrfs_header_nritems(path->nodes[level]))
1420                         continue;
1421                 if (level == 0)
1422                         btrfs_item_key_to_cpu(path->nodes[level], key,
1423                                               path->slots[level] + 1);
1424                 else
1425                         btrfs_node_key_to_cpu(path->nodes[level], key,
1426                                               path->slots[level] + 1);
1427                 return 0;
1428         }
1429         return 1;
1430 }
1431
1432 /*
1433  * look for inline back ref. if back ref is found, *ref_ret is set
1434  * to the address of inline back ref, and 0 is returned.
1435  *
1436  * if back ref isn't found, *ref_ret is set to the address where it
1437  * should be inserted, and -ENOENT is returned.
1438  *
1439  * if insert is true and there are too many inline back refs, the path
1440  * points to the extent item, and -EAGAIN is returned.
1441  *
1442  * NOTE: inline back refs are ordered in the same way that back ref
1443  *       items in the tree are ordered.
1444  */
1445 static noinline_for_stack
1446 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1447                                  struct btrfs_root *root,
1448                                  struct btrfs_path *path,
1449                                  struct btrfs_extent_inline_ref **ref_ret,
1450                                  u64 bytenr, u64 num_bytes,
1451                                  u64 parent, u64 root_objectid,
1452                                  u64 owner, u64 offset, int insert)
1453 {
1454         struct btrfs_key key;
1455         struct extent_buffer *leaf;
1456         struct btrfs_extent_item *ei;
1457         struct btrfs_extent_inline_ref *iref;
1458         u64 flags;
1459         u64 item_size;
1460         unsigned long ptr;
1461         unsigned long end;
1462         int extra_size;
1463         int type;
1464         int want;
1465         int ret;
1466         int err = 0;
1467         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1468                                                  SKINNY_METADATA);
1469
1470         key.objectid = bytenr;
1471         key.type = BTRFS_EXTENT_ITEM_KEY;
1472         key.offset = num_bytes;
1473
1474         want = extent_ref_type(parent, owner);
1475         if (insert) {
1476                 extra_size = btrfs_extent_inline_ref_size(want);
1477                 path->keep_locks = 1;
1478         } else
1479                 extra_size = -1;
1480
1481         /*
1482          * Owner is our parent level, so we can just add one to get the level
1483          * for the block we are interested in.
1484          */
1485         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1486                 key.type = BTRFS_METADATA_ITEM_KEY;
1487                 key.offset = owner;
1488         }
1489
1490 again:
1491         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1492         if (ret < 0) {
1493                 err = ret;
1494                 goto out;
1495         }
1496
1497         /*
1498          * We may be a newly converted file system which still has the old fat
1499          * extent entries for metadata, so try and see if we have one of those.
1500          */
1501         if (ret > 0 && skinny_metadata) {
1502                 skinny_metadata = false;
1503                 if (path->slots[0]) {
1504                         path->slots[0]--;
1505                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1506                                               path->slots[0]);
1507                         if (key.objectid == bytenr &&
1508                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1509                             key.offset == num_bytes)
1510                                 ret = 0;
1511                 }
1512                 if (ret) {
1513                         key.type = BTRFS_EXTENT_ITEM_KEY;
1514                         key.offset = num_bytes;
1515                         btrfs_release_path(path);
1516                         goto again;
1517                 }
1518         }
1519
1520         if (ret && !insert) {
1521                 err = -ENOENT;
1522                 goto out;
1523         } else if (ret) {
1524                 err = -EIO;
1525                 WARN_ON(1);
1526                 goto out;
1527         }
1528
1529         leaf = path->nodes[0];
1530         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1531 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1532         if (item_size < sizeof(*ei)) {
1533                 if (!insert) {
1534                         err = -ENOENT;
1535                         goto out;
1536                 }
1537                 ret = convert_extent_item_v0(trans, root, path, owner,
1538                                              extra_size);
1539                 if (ret < 0) {
1540                         err = ret;
1541                         goto out;
1542                 }
1543                 leaf = path->nodes[0];
1544                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1545         }
1546 #endif
1547         BUG_ON(item_size < sizeof(*ei));
1548
1549         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1550         flags = btrfs_extent_flags(leaf, ei);
1551
1552         ptr = (unsigned long)(ei + 1);
1553         end = (unsigned long)ei + item_size;
1554
1555         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1556                 ptr += sizeof(struct btrfs_tree_block_info);
1557                 BUG_ON(ptr > end);
1558         }
1559
1560         err = -ENOENT;
1561         while (1) {
1562                 if (ptr >= end) {
1563                         WARN_ON(ptr > end);
1564                         break;
1565                 }
1566                 iref = (struct btrfs_extent_inline_ref *)ptr;
1567                 type = btrfs_extent_inline_ref_type(leaf, iref);
1568                 if (want < type)
1569                         break;
1570                 if (want > type) {
1571                         ptr += btrfs_extent_inline_ref_size(type);
1572                         continue;
1573                 }
1574
1575                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1576                         struct btrfs_extent_data_ref *dref;
1577                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1578                         if (match_extent_data_ref(leaf, dref, root_objectid,
1579                                                   owner, offset)) {
1580                                 err = 0;
1581                                 break;
1582                         }
1583                         if (hash_extent_data_ref_item(leaf, dref) <
1584                             hash_extent_data_ref(root_objectid, owner, offset))
1585                                 break;
1586                 } else {
1587                         u64 ref_offset;
1588                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1589                         if (parent > 0) {
1590                                 if (parent == ref_offset) {
1591                                         err = 0;
1592                                         break;
1593                                 }
1594                                 if (ref_offset < parent)
1595                                         break;
1596                         } else {
1597                                 if (root_objectid == ref_offset) {
1598                                         err = 0;
1599                                         break;
1600                                 }
1601                                 if (ref_offset < root_objectid)
1602                                         break;
1603                         }
1604                 }
1605                 ptr += btrfs_extent_inline_ref_size(type);
1606         }
1607         if (err == -ENOENT && insert) {
1608                 if (item_size + extra_size >=
1609                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1610                         err = -EAGAIN;
1611                         goto out;
1612                 }
1613                 /*
1614                  * To add new inline back ref, we have to make sure
1615                  * there is no corresponding back ref item.
1616                  * For simplicity, we just do not add new inline back
1617                  * ref if there is any kind of item for this block
1618                  */
1619                 if (find_next_key(path, 0, &key) == 0 &&
1620                     key.objectid == bytenr &&
1621                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1622                         err = -EAGAIN;
1623                         goto out;
1624                 }
1625         }
1626         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1627 out:
1628         if (insert) {
1629                 path->keep_locks = 0;
1630                 btrfs_unlock_up_safe(path, 1);
1631         }
1632         return err;
1633 }
1634
1635 /*
1636  * helper to add new inline back ref
1637  */
1638 static noinline_for_stack
1639 void setup_inline_extent_backref(struct btrfs_root *root,
1640                                  struct btrfs_path *path,
1641                                  struct btrfs_extent_inline_ref *iref,
1642                                  u64 parent, u64 root_objectid,
1643                                  u64 owner, u64 offset, int refs_to_add,
1644                                  struct btrfs_delayed_extent_op *extent_op)
1645 {
1646         struct extent_buffer *leaf;
1647         struct btrfs_extent_item *ei;
1648         unsigned long ptr;
1649         unsigned long end;
1650         unsigned long item_offset;
1651         u64 refs;
1652         int size;
1653         int type;
1654
1655         leaf = path->nodes[0];
1656         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1657         item_offset = (unsigned long)iref - (unsigned long)ei;
1658
1659         type = extent_ref_type(parent, owner);
1660         size = btrfs_extent_inline_ref_size(type);
1661
1662         btrfs_extend_item(root, path, size);
1663
1664         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1665         refs = btrfs_extent_refs(leaf, ei);
1666         refs += refs_to_add;
1667         btrfs_set_extent_refs(leaf, ei, refs);
1668         if (extent_op)
1669                 __run_delayed_extent_op(extent_op, leaf, ei);
1670
1671         ptr = (unsigned long)ei + item_offset;
1672         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1673         if (ptr < end - size)
1674                 memmove_extent_buffer(leaf, ptr + size, ptr,
1675                                       end - size - ptr);
1676
1677         iref = (struct btrfs_extent_inline_ref *)ptr;
1678         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1679         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1680                 struct btrfs_extent_data_ref *dref;
1681                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1682                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1683                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1684                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1685                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1686         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1687                 struct btrfs_shared_data_ref *sref;
1688                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1689                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1690                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1691         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1692                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1693         } else {
1694                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1695         }
1696         btrfs_mark_buffer_dirty(leaf);
1697 }
1698
1699 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1700                                  struct btrfs_root *root,
1701                                  struct btrfs_path *path,
1702                                  struct btrfs_extent_inline_ref **ref_ret,
1703                                  u64 bytenr, u64 num_bytes, u64 parent,
1704                                  u64 root_objectid, u64 owner, u64 offset)
1705 {
1706         int ret;
1707
1708         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1709                                            bytenr, num_bytes, parent,
1710                                            root_objectid, owner, offset, 0);
1711         if (ret != -ENOENT)
1712                 return ret;
1713
1714         btrfs_release_path(path);
1715         *ref_ret = NULL;
1716
1717         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1718                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1719                                             root_objectid);
1720         } else {
1721                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1722                                              root_objectid, owner, offset);
1723         }
1724         return ret;
1725 }
1726
1727 /*
1728  * helper to update/remove inline back ref
1729  */
1730 static noinline_for_stack
1731 void update_inline_extent_backref(struct btrfs_root *root,
1732                                   struct btrfs_path *path,
1733                                   struct btrfs_extent_inline_ref *iref,
1734                                   int refs_to_mod,
1735                                   struct btrfs_delayed_extent_op *extent_op)
1736 {
1737         struct extent_buffer *leaf;
1738         struct btrfs_extent_item *ei;
1739         struct btrfs_extent_data_ref *dref = NULL;
1740         struct btrfs_shared_data_ref *sref = NULL;
1741         unsigned long ptr;
1742         unsigned long end;
1743         u32 item_size;
1744         int size;
1745         int type;
1746         u64 refs;
1747
1748         leaf = path->nodes[0];
1749         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1750         refs = btrfs_extent_refs(leaf, ei);
1751         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1752         refs += refs_to_mod;
1753         btrfs_set_extent_refs(leaf, ei, refs);
1754         if (extent_op)
1755                 __run_delayed_extent_op(extent_op, leaf, ei);
1756
1757         type = btrfs_extent_inline_ref_type(leaf, iref);
1758
1759         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1760                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1761                 refs = btrfs_extent_data_ref_count(leaf, dref);
1762         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1763                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1764                 refs = btrfs_shared_data_ref_count(leaf, sref);
1765         } else {
1766                 refs = 1;
1767                 BUG_ON(refs_to_mod != -1);
1768         }
1769
1770         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1771         refs += refs_to_mod;
1772
1773         if (refs > 0) {
1774                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1775                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1776                 else
1777                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1778         } else {
1779                 size =  btrfs_extent_inline_ref_size(type);
1780                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1781                 ptr = (unsigned long)iref;
1782                 end = (unsigned long)ei + item_size;
1783                 if (ptr + size < end)
1784                         memmove_extent_buffer(leaf, ptr, ptr + size,
1785                                               end - ptr - size);
1786                 item_size -= size;
1787                 btrfs_truncate_item(root, path, item_size, 1);
1788         }
1789         btrfs_mark_buffer_dirty(leaf);
1790 }
1791
1792 static noinline_for_stack
1793 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1794                                  struct btrfs_root *root,
1795                                  struct btrfs_path *path,
1796                                  u64 bytenr, u64 num_bytes, u64 parent,
1797                                  u64 root_objectid, u64 owner,
1798                                  u64 offset, int refs_to_add,
1799                                  struct btrfs_delayed_extent_op *extent_op)
1800 {
1801         struct btrfs_extent_inline_ref *iref;
1802         int ret;
1803
1804         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1805                                            bytenr, num_bytes, parent,
1806                                            root_objectid, owner, offset, 1);
1807         if (ret == 0) {
1808                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1809                 update_inline_extent_backref(root, path, iref,
1810                                              refs_to_add, extent_op);
1811         } else if (ret == -ENOENT) {
1812                 setup_inline_extent_backref(root, path, iref, parent,
1813                                             root_objectid, owner, offset,
1814                                             refs_to_add, extent_op);
1815                 ret = 0;
1816         }
1817         return ret;
1818 }
1819
1820 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1821                                  struct btrfs_root *root,
1822                                  struct btrfs_path *path,
1823                                  u64 bytenr, u64 parent, u64 root_objectid,
1824                                  u64 owner, u64 offset, int refs_to_add)
1825 {
1826         int ret;
1827         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1828                 BUG_ON(refs_to_add != 1);
1829                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1830                                             parent, root_objectid);
1831         } else {
1832                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1833                                              parent, root_objectid,
1834                                              owner, offset, refs_to_add);
1835         }
1836         return ret;
1837 }
1838
1839 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1840                                  struct btrfs_root *root,
1841                                  struct btrfs_path *path,
1842                                  struct btrfs_extent_inline_ref *iref,
1843                                  int refs_to_drop, int is_data)
1844 {
1845         int ret = 0;
1846
1847         BUG_ON(!is_data && refs_to_drop != 1);
1848         if (iref) {
1849                 update_inline_extent_backref(root, path, iref,
1850                                              -refs_to_drop, NULL);
1851         } else if (is_data) {
1852                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1853         } else {
1854                 ret = btrfs_del_item(trans, root, path);
1855         }
1856         return ret;
1857 }
1858
1859 static int btrfs_issue_discard(struct block_device *bdev,
1860                                 u64 start, u64 len)
1861 {
1862         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1863 }
1864
1865 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1866                                 u64 num_bytes, u64 *actual_bytes)
1867 {
1868         int ret;
1869         u64 discarded_bytes = 0;
1870         struct btrfs_bio *bbio = NULL;
1871
1872
1873         /* Tell the block device(s) that the sectors can be discarded */
1874         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1875                               bytenr, &num_bytes, &bbio, 0);
1876         /* Error condition is -ENOMEM */
1877         if (!ret) {
1878                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1879                 int i;
1880
1881
1882                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1883                         if (!stripe->dev->can_discard)
1884                                 continue;
1885
1886                         ret = btrfs_issue_discard(stripe->dev->bdev,
1887                                                   stripe->physical,
1888                                                   stripe->length);
1889                         if (!ret)
1890                                 discarded_bytes += stripe->length;
1891                         else if (ret != -EOPNOTSUPP)
1892                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1893
1894                         /*
1895                          * Just in case we get back EOPNOTSUPP for some reason,
1896                          * just ignore the return value so we don't screw up
1897                          * people calling discard_extent.
1898                          */
1899                         ret = 0;
1900                 }
1901                 kfree(bbio);
1902         }
1903
1904         if (actual_bytes)
1905                 *actual_bytes = discarded_bytes;
1906
1907
1908         if (ret == -EOPNOTSUPP)
1909                 ret = 0;
1910         return ret;
1911 }
1912
1913 /* Can return -ENOMEM */
1914 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1915                          struct btrfs_root *root,
1916                          u64 bytenr, u64 num_bytes, u64 parent,
1917                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1918 {
1919         int ret;
1920         struct btrfs_fs_info *fs_info = root->fs_info;
1921
1922         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1923                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1924
1925         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1926                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1927                                         num_bytes,
1928                                         parent, root_objectid, (int)owner,
1929                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1930         } else {
1931                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1932                                         num_bytes,
1933                                         parent, root_objectid, owner, offset,
1934                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1935         }
1936         return ret;
1937 }
1938
1939 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1940                                   struct btrfs_root *root,
1941                                   u64 bytenr, u64 num_bytes,
1942                                   u64 parent, u64 root_objectid,
1943                                   u64 owner, u64 offset, int refs_to_add,
1944                                   struct btrfs_delayed_extent_op *extent_op)
1945 {
1946         struct btrfs_path *path;
1947         struct extent_buffer *leaf;
1948         struct btrfs_extent_item *item;
1949         u64 refs;
1950         int ret;
1951         int err = 0;
1952
1953         path = btrfs_alloc_path();
1954         if (!path)
1955                 return -ENOMEM;
1956
1957         path->reada = 1;
1958         path->leave_spinning = 1;
1959         /* this will setup the path even if it fails to insert the back ref */
1960         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1961                                            path, bytenr, num_bytes, parent,
1962                                            root_objectid, owner, offset,
1963                                            refs_to_add, extent_op);
1964         if (ret == 0)
1965                 goto out;
1966
1967         if (ret != -EAGAIN) {
1968                 err = ret;
1969                 goto out;
1970         }
1971
1972         leaf = path->nodes[0];
1973         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1974         refs = btrfs_extent_refs(leaf, item);
1975         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1976         if (extent_op)
1977                 __run_delayed_extent_op(extent_op, leaf, item);
1978
1979         btrfs_mark_buffer_dirty(leaf);
1980         btrfs_release_path(path);
1981
1982         path->reada = 1;
1983         path->leave_spinning = 1;
1984
1985         /* now insert the actual backref */
1986         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1987                                     path, bytenr, parent, root_objectid,
1988                                     owner, offset, refs_to_add);
1989         if (ret)
1990                 btrfs_abort_transaction(trans, root, ret);
1991 out:
1992         btrfs_free_path(path);
1993         return err;
1994 }
1995
1996 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1997                                 struct btrfs_root *root,
1998                                 struct btrfs_delayed_ref_node *node,
1999                                 struct btrfs_delayed_extent_op *extent_op,
2000                                 int insert_reserved)
2001 {
2002         int ret = 0;
2003         struct btrfs_delayed_data_ref *ref;
2004         struct btrfs_key ins;
2005         u64 parent = 0;
2006         u64 ref_root = 0;
2007         u64 flags = 0;
2008
2009         ins.objectid = node->bytenr;
2010         ins.offset = node->num_bytes;
2011         ins.type = BTRFS_EXTENT_ITEM_KEY;
2012
2013         ref = btrfs_delayed_node_to_data_ref(node);
2014         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2015                 parent = ref->parent;
2016         else
2017                 ref_root = ref->root;
2018
2019         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2020                 if (extent_op)
2021                         flags |= extent_op->flags_to_set;
2022                 ret = alloc_reserved_file_extent(trans, root,
2023                                                  parent, ref_root, flags,
2024                                                  ref->objectid, ref->offset,
2025                                                  &ins, node->ref_mod);
2026         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2027                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2028                                              node->num_bytes, parent,
2029                                              ref_root, ref->objectid,
2030                                              ref->offset, node->ref_mod,
2031                                              extent_op);
2032         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2033                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2034                                           node->num_bytes, parent,
2035                                           ref_root, ref->objectid,
2036                                           ref->offset, node->ref_mod,
2037                                           extent_op);
2038         } else {
2039                 BUG();
2040         }
2041         return ret;
2042 }
2043
2044 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2045                                     struct extent_buffer *leaf,
2046                                     struct btrfs_extent_item *ei)
2047 {
2048         u64 flags = btrfs_extent_flags(leaf, ei);
2049         if (extent_op->update_flags) {
2050                 flags |= extent_op->flags_to_set;
2051                 btrfs_set_extent_flags(leaf, ei, flags);
2052         }
2053
2054         if (extent_op->update_key) {
2055                 struct btrfs_tree_block_info *bi;
2056                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2057                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2058                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2059         }
2060 }
2061
2062 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2063                                  struct btrfs_root *root,
2064                                  struct btrfs_delayed_ref_node *node,
2065                                  struct btrfs_delayed_extent_op *extent_op)
2066 {
2067         struct btrfs_key key;
2068         struct btrfs_path *path;
2069         struct btrfs_extent_item *ei;
2070         struct extent_buffer *leaf;
2071         u32 item_size;
2072         int ret;
2073         int err = 0;
2074         int metadata = !extent_op->is_data;
2075
2076         if (trans->aborted)
2077                 return 0;
2078
2079         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2080                 metadata = 0;
2081
2082         path = btrfs_alloc_path();
2083         if (!path)
2084                 return -ENOMEM;
2085
2086         key.objectid = node->bytenr;
2087
2088         if (metadata) {
2089                 key.type = BTRFS_METADATA_ITEM_KEY;
2090                 key.offset = extent_op->level;
2091         } else {
2092                 key.type = BTRFS_EXTENT_ITEM_KEY;
2093                 key.offset = node->num_bytes;
2094         }
2095
2096 again:
2097         path->reada = 1;
2098         path->leave_spinning = 1;
2099         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2100                                 path, 0, 1);
2101         if (ret < 0) {
2102                 err = ret;
2103                 goto out;
2104         }
2105         if (ret > 0) {
2106                 if (metadata) {
2107                         btrfs_release_path(path);
2108                         metadata = 0;
2109
2110                         key.offset = node->num_bytes;
2111                         key.type = BTRFS_EXTENT_ITEM_KEY;
2112                         goto again;
2113                 }
2114                 err = -EIO;
2115                 goto out;
2116         }
2117
2118         leaf = path->nodes[0];
2119         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2120 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2121         if (item_size < sizeof(*ei)) {
2122                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2123                                              path, (u64)-1, 0);
2124                 if (ret < 0) {
2125                         err = ret;
2126                         goto out;
2127                 }
2128                 leaf = path->nodes[0];
2129                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2130         }
2131 #endif
2132         BUG_ON(item_size < sizeof(*ei));
2133         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2134         __run_delayed_extent_op(extent_op, leaf, ei);
2135
2136         btrfs_mark_buffer_dirty(leaf);
2137 out:
2138         btrfs_free_path(path);
2139         return err;
2140 }
2141
2142 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2143                                 struct btrfs_root *root,
2144                                 struct btrfs_delayed_ref_node *node,
2145                                 struct btrfs_delayed_extent_op *extent_op,
2146                                 int insert_reserved)
2147 {
2148         int ret = 0;
2149         struct btrfs_delayed_tree_ref *ref;
2150         struct btrfs_key ins;
2151         u64 parent = 0;
2152         u64 ref_root = 0;
2153         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2154                                                  SKINNY_METADATA);
2155
2156         ref = btrfs_delayed_node_to_tree_ref(node);
2157         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2158                 parent = ref->parent;
2159         else
2160                 ref_root = ref->root;
2161
2162         ins.objectid = node->bytenr;
2163         if (skinny_metadata) {
2164                 ins.offset = ref->level;
2165                 ins.type = BTRFS_METADATA_ITEM_KEY;
2166         } else {
2167                 ins.offset = node->num_bytes;
2168                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2169         }
2170
2171         BUG_ON(node->ref_mod != 1);
2172         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2173                 BUG_ON(!extent_op || !extent_op->update_flags);
2174                 ret = alloc_reserved_tree_block(trans, root,
2175                                                 parent, ref_root,
2176                                                 extent_op->flags_to_set,
2177                                                 &extent_op->key,
2178                                                 ref->level, &ins);
2179         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2180                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2181                                              node->num_bytes, parent, ref_root,
2182                                              ref->level, 0, 1, extent_op);
2183         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2184                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2185                                           node->num_bytes, parent, ref_root,
2186                                           ref->level, 0, 1, extent_op);
2187         } else {
2188                 BUG();
2189         }
2190         return ret;
2191 }
2192
2193 /* helper function to actually process a single delayed ref entry */
2194 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2195                                struct btrfs_root *root,
2196                                struct btrfs_delayed_ref_node *node,
2197                                struct btrfs_delayed_extent_op *extent_op,
2198                                int insert_reserved)
2199 {
2200         int ret = 0;
2201
2202         if (trans->aborted)
2203                 return 0;
2204
2205         if (btrfs_delayed_ref_is_head(node)) {
2206                 struct btrfs_delayed_ref_head *head;
2207                 /*
2208                  * we've hit the end of the chain and we were supposed
2209                  * to insert this extent into the tree.  But, it got
2210                  * deleted before we ever needed to insert it, so all
2211                  * we have to do is clean up the accounting
2212                  */
2213                 BUG_ON(extent_op);
2214                 head = btrfs_delayed_node_to_head(node);
2215                 if (insert_reserved) {
2216                         btrfs_pin_extent(root, node->bytenr,
2217                                          node->num_bytes, 1);
2218                         if (head->is_data) {
2219                                 ret = btrfs_del_csums(trans, root,
2220                                                       node->bytenr,
2221                                                       node->num_bytes);
2222                         }
2223                 }
2224                 return ret;
2225         }
2226
2227         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2228             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2229                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2230                                            insert_reserved);
2231         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2232                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2233                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2234                                            insert_reserved);
2235         else
2236                 BUG();
2237         return ret;
2238 }
2239
2240 static noinline struct btrfs_delayed_ref_node *
2241 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2242 {
2243         struct rb_node *node;
2244         struct btrfs_delayed_ref_node *ref;
2245         int action = BTRFS_ADD_DELAYED_REF;
2246 again:
2247         /*
2248          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2249          * this prevents ref count from going down to zero when
2250          * there still are pending delayed ref.
2251          */
2252         node = rb_prev(&head->node.rb_node);
2253         while (1) {
2254                 if (!node)
2255                         break;
2256                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2257                                 rb_node);
2258                 if (ref->bytenr != head->node.bytenr)
2259                         break;
2260                 if (ref->action == action)
2261                         return ref;
2262                 node = rb_prev(node);
2263         }
2264         if (action == BTRFS_ADD_DELAYED_REF) {
2265                 action = BTRFS_DROP_DELAYED_REF;
2266                 goto again;
2267         }
2268         return NULL;
2269 }
2270
2271 /*
2272  * Returns 0 on success or if called with an already aborted transaction.
2273  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2274  */
2275 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2276                                        struct btrfs_root *root,
2277                                        struct list_head *cluster)
2278 {
2279         struct btrfs_delayed_ref_root *delayed_refs;
2280         struct btrfs_delayed_ref_node *ref;
2281         struct btrfs_delayed_ref_head *locked_ref = NULL;
2282         struct btrfs_delayed_extent_op *extent_op;
2283         struct btrfs_fs_info *fs_info = root->fs_info;
2284         int ret;
2285         int count = 0;
2286         int must_insert_reserved = 0;
2287
2288         delayed_refs = &trans->transaction->delayed_refs;
2289         while (1) {
2290                 if (!locked_ref) {
2291                         /* pick a new head ref from the cluster list */
2292                         if (list_empty(cluster))
2293                                 break;
2294
2295                         locked_ref = list_entry(cluster->next,
2296                                      struct btrfs_delayed_ref_head, cluster);
2297
2298                         /* grab the lock that says we are going to process
2299                          * all the refs for this head */
2300                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2301
2302                         /*
2303                          * we may have dropped the spin lock to get the head
2304                          * mutex lock, and that might have given someone else
2305                          * time to free the head.  If that's true, it has been
2306                          * removed from our list and we can move on.
2307                          */
2308                         if (ret == -EAGAIN) {
2309                                 locked_ref = NULL;
2310                                 count++;
2311                                 continue;
2312                         }
2313                 }
2314
2315                 /*
2316                  * We need to try and merge add/drops of the same ref since we
2317                  * can run into issues with relocate dropping the implicit ref
2318                  * and then it being added back again before the drop can
2319                  * finish.  If we merged anything we need to re-loop so we can
2320                  * get a good ref.
2321                  */
2322                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2323                                          locked_ref);
2324
2325                 /*
2326                  * locked_ref is the head node, so we have to go one
2327                  * node back for any delayed ref updates
2328                  */
2329                 ref = select_delayed_ref(locked_ref);
2330
2331                 if (ref && ref->seq &&
2332                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2333                         /*
2334                          * there are still refs with lower seq numbers in the
2335                          * process of being added. Don't run this ref yet.
2336                          */
2337                         list_del_init(&locked_ref->cluster);
2338                         btrfs_delayed_ref_unlock(locked_ref);
2339                         locked_ref = NULL;
2340                         delayed_refs->num_heads_ready++;
2341                         spin_unlock(&delayed_refs->lock);
2342                         cond_resched();
2343                         spin_lock(&delayed_refs->lock);
2344                         continue;
2345                 }
2346
2347                 /*
2348                  * record the must insert reserved flag before we
2349                  * drop the spin lock.
2350                  */
2351                 must_insert_reserved = locked_ref->must_insert_reserved;
2352                 locked_ref->must_insert_reserved = 0;
2353
2354                 extent_op = locked_ref->extent_op;
2355                 locked_ref->extent_op = NULL;
2356
2357                 if (!ref) {
2358                         /* All delayed refs have been processed, Go ahead
2359                          * and send the head node to run_one_delayed_ref,
2360                          * so that any accounting fixes can happen
2361                          */
2362                         ref = &locked_ref->node;
2363
2364                         if (extent_op && must_insert_reserved) {
2365                                 btrfs_free_delayed_extent_op(extent_op);
2366                                 extent_op = NULL;
2367                         }
2368
2369                         if (extent_op) {
2370                                 spin_unlock(&delayed_refs->lock);
2371
2372                                 ret = run_delayed_extent_op(trans, root,
2373                                                             ref, extent_op);
2374                                 btrfs_free_delayed_extent_op(extent_op);
2375
2376                                 if (ret) {
2377                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2378                                         spin_lock(&delayed_refs->lock);
2379                                         btrfs_delayed_ref_unlock(locked_ref);
2380                                         return ret;
2381                                 }
2382
2383                                 goto next;
2384                         }
2385                 }
2386
2387                 ref->in_tree = 0;
2388                 rb_erase(&ref->rb_node, &delayed_refs->root);
2389                 delayed_refs->num_entries--;
2390                 if (!btrfs_delayed_ref_is_head(ref)) {
2391                         /*
2392                          * when we play the delayed ref, also correct the
2393                          * ref_mod on head
2394                          */
2395                         switch (ref->action) {
2396                         case BTRFS_ADD_DELAYED_REF:
2397                         case BTRFS_ADD_DELAYED_EXTENT:
2398                                 locked_ref->node.ref_mod -= ref->ref_mod;
2399                                 break;
2400                         case BTRFS_DROP_DELAYED_REF:
2401                                 locked_ref->node.ref_mod += ref->ref_mod;
2402                                 break;
2403                         default:
2404                                 WARN_ON(1);
2405                         }
2406                 }
2407                 spin_unlock(&delayed_refs->lock);
2408
2409                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2410                                           must_insert_reserved);
2411
2412                 btrfs_free_delayed_extent_op(extent_op);
2413                 if (ret) {
2414                         btrfs_delayed_ref_unlock(locked_ref);
2415                         btrfs_put_delayed_ref(ref);
2416                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2417                         spin_lock(&delayed_refs->lock);
2418                         return ret;
2419                 }
2420
2421                 /*
2422                  * If this node is a head, that means all the refs in this head
2423                  * have been dealt with, and we will pick the next head to deal
2424                  * with, so we must unlock the head and drop it from the cluster
2425                  * list before we release it.
2426                  */
2427                 if (btrfs_delayed_ref_is_head(ref)) {
2428                         list_del_init(&locked_ref->cluster);
2429                         btrfs_delayed_ref_unlock(locked_ref);
2430                         locked_ref = NULL;
2431                 }
2432                 btrfs_put_delayed_ref(ref);
2433                 count++;
2434 next:
2435                 cond_resched();
2436                 spin_lock(&delayed_refs->lock);
2437         }
2438         return count;
2439 }
2440
2441 #ifdef SCRAMBLE_DELAYED_REFS
2442 /*
2443  * Normally delayed refs get processed in ascending bytenr order. This
2444  * correlates in most cases to the order added. To expose dependencies on this
2445  * order, we start to process the tree in the middle instead of the beginning
2446  */
2447 static u64 find_middle(struct rb_root *root)
2448 {
2449         struct rb_node *n = root->rb_node;
2450         struct btrfs_delayed_ref_node *entry;
2451         int alt = 1;
2452         u64 middle;
2453         u64 first = 0, last = 0;
2454
2455         n = rb_first(root);
2456         if (n) {
2457                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2458                 first = entry->bytenr;
2459         }
2460         n = rb_last(root);
2461         if (n) {
2462                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2463                 last = entry->bytenr;
2464         }
2465         n = root->rb_node;
2466
2467         while (n) {
2468                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2469                 WARN_ON(!entry->in_tree);
2470
2471                 middle = entry->bytenr;
2472
2473                 if (alt)
2474                         n = n->rb_left;
2475                 else
2476                         n = n->rb_right;
2477
2478                 alt = 1 - alt;
2479         }
2480         return middle;
2481 }
2482 #endif
2483
2484 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2485                                          struct btrfs_fs_info *fs_info)
2486 {
2487         struct qgroup_update *qgroup_update;
2488         int ret = 0;
2489
2490         if (list_empty(&trans->qgroup_ref_list) !=
2491             !trans->delayed_ref_elem.seq) {
2492                 /* list without seq or seq without list */
2493                 btrfs_err(fs_info,
2494                         "qgroup accounting update error, list is%s empty, seq is %#x.%x",
2495                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2496                         (u32)(trans->delayed_ref_elem.seq >> 32),
2497                         (u32)trans->delayed_ref_elem.seq);
2498                 BUG();
2499         }
2500
2501         if (!trans->delayed_ref_elem.seq)
2502                 return 0;
2503
2504         while (!list_empty(&trans->qgroup_ref_list)) {
2505                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2506                                                  struct qgroup_update, list);
2507                 list_del(&qgroup_update->list);
2508                 if (!ret)
2509                         ret = btrfs_qgroup_account_ref(
2510                                         trans, fs_info, qgroup_update->node,
2511                                         qgroup_update->extent_op);
2512                 kfree(qgroup_update);
2513         }
2514
2515         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2516
2517         return ret;
2518 }
2519
2520 static int refs_newer(struct btrfs_delayed_ref_root *delayed_refs, int seq,
2521                       int count)
2522 {
2523         int val = atomic_read(&delayed_refs->ref_seq);
2524
2525         if (val < seq || val >= seq + count)
2526                 return 1;
2527         return 0;
2528 }
2529
2530 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2531 {
2532         u64 num_bytes;
2533
2534         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2535                              sizeof(struct btrfs_extent_inline_ref));
2536         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2537                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2538
2539         /*
2540          * We don't ever fill up leaves all the way so multiply by 2 just to be
2541          * closer to what we're really going to want to ouse.
2542          */
2543         return div64_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2544 }
2545
2546 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2547                                        struct btrfs_root *root)
2548 {
2549         struct btrfs_block_rsv *global_rsv;
2550         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2551         u64 num_bytes;
2552         int ret = 0;
2553
2554         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2555         num_heads = heads_to_leaves(root, num_heads);
2556         if (num_heads > 1)
2557                 num_bytes += (num_heads - 1) * root->leafsize;
2558         num_bytes <<= 1;
2559         global_rsv = &root->fs_info->global_block_rsv;
2560
2561         /*
2562          * If we can't allocate any more chunks lets make sure we have _lots_ of
2563          * wiggle room since running delayed refs can create more delayed refs.
2564          */
2565         if (global_rsv->space_info->full)
2566                 num_bytes <<= 1;
2567
2568         spin_lock(&global_rsv->lock);
2569         if (global_rsv->reserved <= num_bytes)
2570                 ret = 1;
2571         spin_unlock(&global_rsv->lock);
2572         return ret;
2573 }
2574
2575 /*
2576  * this starts processing the delayed reference count updates and
2577  * extent insertions we have queued up so far.  count can be
2578  * 0, which means to process everything in the tree at the start
2579  * of the run (but not newly added entries), or it can be some target
2580  * number you'd like to process.
2581  *
2582  * Returns 0 on success or if called with an aborted transaction
2583  * Returns <0 on error and aborts the transaction
2584  */
2585 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2586                            struct btrfs_root *root, unsigned long count)
2587 {
2588         struct rb_node *node;
2589         struct btrfs_delayed_ref_root *delayed_refs;
2590         struct btrfs_delayed_ref_node *ref;
2591         struct list_head cluster;
2592         int ret;
2593         u64 delayed_start;
2594         int run_all = count == (unsigned long)-1;
2595         int run_most = 0;
2596         int loops;
2597
2598         /* We'll clean this up in btrfs_cleanup_transaction */
2599         if (trans->aborted)
2600                 return 0;
2601
2602         if (root == root->fs_info->extent_root)
2603                 root = root->fs_info->tree_root;
2604
2605         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2606
2607         delayed_refs = &trans->transaction->delayed_refs;
2608         INIT_LIST_HEAD(&cluster);
2609         if (count == 0) {
2610                 count = delayed_refs->num_entries * 2;
2611                 run_most = 1;
2612         }
2613
2614         if (!run_all && !run_most) {
2615                 int old;
2616                 int seq = atomic_read(&delayed_refs->ref_seq);
2617
2618 progress:
2619                 old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2620                 if (old) {
2621                         DEFINE_WAIT(__wait);
2622                         if (delayed_refs->flushing ||
2623                             !btrfs_should_throttle_delayed_refs(trans, root))
2624                                 return 0;
2625
2626                         prepare_to_wait(&delayed_refs->wait, &__wait,
2627                                         TASK_UNINTERRUPTIBLE);
2628
2629                         old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2630                         if (old) {
2631                                 schedule();
2632                                 finish_wait(&delayed_refs->wait, &__wait);
2633
2634                                 if (!refs_newer(delayed_refs, seq, 256))
2635                                         goto progress;
2636                                 else
2637                                         return 0;
2638                         } else {
2639                                 finish_wait(&delayed_refs->wait, &__wait);
2640                                 goto again;
2641                         }
2642                 }
2643
2644         } else {
2645                 atomic_inc(&delayed_refs->procs_running_refs);
2646         }
2647
2648 again:
2649         loops = 0;
2650         spin_lock(&delayed_refs->lock);
2651
2652 #ifdef SCRAMBLE_DELAYED_REFS
2653         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2654 #endif
2655
2656         while (1) {
2657                 if (!(run_all || run_most) &&
2658                     !btrfs_should_throttle_delayed_refs(trans, root))
2659                         break;
2660
2661                 /*
2662                  * go find something we can process in the rbtree.  We start at
2663                  * the beginning of the tree, and then build a cluster
2664                  * of refs to process starting at the first one we are able to
2665                  * lock
2666                  */
2667                 delayed_start = delayed_refs->run_delayed_start;
2668                 ret = btrfs_find_ref_cluster(trans, &cluster,
2669                                              delayed_refs->run_delayed_start);
2670                 if (ret)
2671                         break;
2672
2673                 ret = run_clustered_refs(trans, root, &cluster);
2674                 if (ret < 0) {
2675                         btrfs_release_ref_cluster(&cluster);
2676                         spin_unlock(&delayed_refs->lock);
2677                         btrfs_abort_transaction(trans, root, ret);
2678                         atomic_dec(&delayed_refs->procs_running_refs);
2679                         wake_up(&delayed_refs->wait);
2680                         return ret;
2681                 }
2682
2683                 atomic_add(ret, &delayed_refs->ref_seq);
2684
2685                 count -= min_t(unsigned long, ret, count);
2686
2687                 if (count == 0)
2688                         break;
2689
2690                 if (delayed_start >= delayed_refs->run_delayed_start) {
2691                         if (loops == 0) {
2692                                 /*
2693                                  * btrfs_find_ref_cluster looped. let's do one
2694                                  * more cycle. if we don't run any delayed ref
2695                                  * during that cycle (because we can't because
2696                                  * all of them are blocked), bail out.
2697                                  */
2698                                 loops = 1;
2699                         } else {
2700                                 /*
2701                                  * no runnable refs left, stop trying
2702                                  */
2703                                 BUG_ON(run_all);
2704                                 break;
2705                         }
2706                 }
2707                 if (ret) {
2708                         /* refs were run, let's reset staleness detection */
2709                         loops = 0;
2710                 }
2711         }
2712
2713         if (run_all) {
2714                 if (!list_empty(&trans->new_bgs)) {
2715                         spin_unlock(&delayed_refs->lock);
2716                         btrfs_create_pending_block_groups(trans, root);
2717                         spin_lock(&delayed_refs->lock);
2718                 }
2719
2720                 node = rb_first(&delayed_refs->root);
2721                 if (!node)
2722                         goto out;
2723                 count = (unsigned long)-1;
2724
2725                 while (node) {
2726                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2727                                        rb_node);
2728                         if (btrfs_delayed_ref_is_head(ref)) {
2729                                 struct btrfs_delayed_ref_head *head;
2730
2731                                 head = btrfs_delayed_node_to_head(ref);
2732                                 atomic_inc(&ref->refs);
2733
2734                                 spin_unlock(&delayed_refs->lock);
2735                                 /*
2736                                  * Mutex was contended, block until it's
2737                                  * released and try again
2738                                  */
2739                                 mutex_lock(&head->mutex);
2740                                 mutex_unlock(&head->mutex);
2741
2742                                 btrfs_put_delayed_ref(ref);
2743                                 cond_resched();
2744                                 goto again;
2745                         }
2746                         node = rb_next(node);
2747                 }
2748                 spin_unlock(&delayed_refs->lock);
2749                 schedule_timeout(1);
2750                 goto again;
2751         }
2752 out:
2753         atomic_dec(&delayed_refs->procs_running_refs);
2754         smp_mb();
2755         if (waitqueue_active(&delayed_refs->wait))
2756                 wake_up(&delayed_refs->wait);
2757
2758         spin_unlock(&delayed_refs->lock);
2759         assert_qgroups_uptodate(trans);
2760         return 0;
2761 }
2762
2763 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2764                                 struct btrfs_root *root,
2765                                 u64 bytenr, u64 num_bytes, u64 flags,
2766                                 int level, int is_data)
2767 {
2768         struct btrfs_delayed_extent_op *extent_op;
2769         int ret;
2770
2771         extent_op = btrfs_alloc_delayed_extent_op();
2772         if (!extent_op)
2773                 return -ENOMEM;
2774
2775         extent_op->flags_to_set = flags;
2776         extent_op->update_flags = 1;
2777         extent_op->update_key = 0;
2778         extent_op->is_data = is_data ? 1 : 0;
2779         extent_op->level = level;
2780
2781         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2782                                           num_bytes, extent_op);
2783         if (ret)
2784                 btrfs_free_delayed_extent_op(extent_op);
2785         return ret;
2786 }
2787
2788 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2789                                       struct btrfs_root *root,
2790                                       struct btrfs_path *path,
2791                                       u64 objectid, u64 offset, u64 bytenr)
2792 {
2793         struct btrfs_delayed_ref_head *head;
2794         struct btrfs_delayed_ref_node *ref;
2795         struct btrfs_delayed_data_ref *data_ref;
2796         struct btrfs_delayed_ref_root *delayed_refs;
2797         struct rb_node *node;
2798         int ret = 0;
2799
2800         ret = -ENOENT;
2801         delayed_refs = &trans->transaction->delayed_refs;
2802         spin_lock(&delayed_refs->lock);
2803         head = btrfs_find_delayed_ref_head(trans, bytenr);
2804         if (!head)
2805                 goto out;
2806
2807         if (!mutex_trylock(&head->mutex)) {
2808                 atomic_inc(&head->node.refs);
2809                 spin_unlock(&delayed_refs->lock);
2810
2811                 btrfs_release_path(path);
2812
2813                 /*
2814                  * Mutex was contended, block until it's released and let
2815                  * caller try again
2816                  */
2817                 mutex_lock(&head->mutex);
2818                 mutex_unlock(&head->mutex);
2819                 btrfs_put_delayed_ref(&head->node);
2820                 return -EAGAIN;
2821         }
2822
2823         node = rb_prev(&head->node.rb_node);
2824         if (!node)
2825                 goto out_unlock;
2826
2827         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2828
2829         if (ref->bytenr != bytenr)
2830                 goto out_unlock;
2831
2832         ret = 1;
2833         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2834                 goto out_unlock;
2835
2836         data_ref = btrfs_delayed_node_to_data_ref(ref);
2837
2838         node = rb_prev(node);
2839         if (node) {
2840                 int seq = ref->seq;
2841
2842                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2843                 if (ref->bytenr == bytenr && ref->seq == seq)
2844                         goto out_unlock;
2845         }
2846
2847         if (data_ref->root != root->root_key.objectid ||
2848             data_ref->objectid != objectid || data_ref->offset != offset)
2849                 goto out_unlock;
2850
2851         ret = 0;
2852 out_unlock:
2853         mutex_unlock(&head->mutex);
2854 out:
2855         spin_unlock(&delayed_refs->lock);
2856         return ret;
2857 }
2858
2859 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2860                                         struct btrfs_root *root,
2861                                         struct btrfs_path *path,
2862                                         u64 objectid, u64 offset, u64 bytenr)
2863 {
2864         struct btrfs_root *extent_root = root->fs_info->extent_root;
2865         struct extent_buffer *leaf;
2866         struct btrfs_extent_data_ref *ref;
2867         struct btrfs_extent_inline_ref *iref;
2868         struct btrfs_extent_item *ei;
2869         struct btrfs_key key;
2870         u32 item_size;
2871         int ret;
2872
2873         key.objectid = bytenr;
2874         key.offset = (u64)-1;
2875         key.type = BTRFS_EXTENT_ITEM_KEY;
2876
2877         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2878         if (ret < 0)
2879                 goto out;
2880         BUG_ON(ret == 0); /* Corruption */
2881
2882         ret = -ENOENT;
2883         if (path->slots[0] == 0)
2884                 goto out;
2885
2886         path->slots[0]--;
2887         leaf = path->nodes[0];
2888         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2889
2890         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2891                 goto out;
2892
2893         ret = 1;
2894         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2895 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2896         if (item_size < sizeof(*ei)) {
2897                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2898                 goto out;
2899         }
2900 #endif
2901         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2902
2903         if (item_size != sizeof(*ei) +
2904             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2905                 goto out;
2906
2907         if (btrfs_extent_generation(leaf, ei) <=
2908             btrfs_root_last_snapshot(&root->root_item))
2909                 goto out;
2910
2911         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2912         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2913             BTRFS_EXTENT_DATA_REF_KEY)
2914                 goto out;
2915
2916         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2917         if (btrfs_extent_refs(leaf, ei) !=
2918             btrfs_extent_data_ref_count(leaf, ref) ||
2919             btrfs_extent_data_ref_root(leaf, ref) !=
2920             root->root_key.objectid ||
2921             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2922             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2923                 goto out;
2924
2925         ret = 0;
2926 out:
2927         return ret;
2928 }
2929
2930 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2931                           struct btrfs_root *root,
2932                           u64 objectid, u64 offset, u64 bytenr)
2933 {
2934         struct btrfs_path *path;
2935         int ret;
2936         int ret2;
2937
2938         path = btrfs_alloc_path();
2939         if (!path)
2940                 return -ENOENT;
2941
2942         do {
2943                 ret = check_committed_ref(trans, root, path, objectid,
2944                                           offset, bytenr);
2945                 if (ret && ret != -ENOENT)
2946                         goto out;
2947
2948                 ret2 = check_delayed_ref(trans, root, path, objectid,
2949                                          offset, bytenr);
2950         } while (ret2 == -EAGAIN);
2951
2952         if (ret2 && ret2 != -ENOENT) {
2953                 ret = ret2;
2954                 goto out;
2955         }
2956
2957         if (ret != -ENOENT || ret2 != -ENOENT)
2958                 ret = 0;
2959 out:
2960         btrfs_free_path(path);
2961         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2962                 WARN_ON(ret > 0);
2963         return ret;
2964 }
2965
2966 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2967                            struct btrfs_root *root,
2968                            struct extent_buffer *buf,
2969                            int full_backref, int inc, int for_cow)
2970 {
2971         u64 bytenr;
2972         u64 num_bytes;
2973         u64 parent;
2974         u64 ref_root;
2975         u32 nritems;
2976         struct btrfs_key key;
2977         struct btrfs_file_extent_item *fi;
2978         int i;
2979         int level;
2980         int ret = 0;
2981         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2982                             u64, u64, u64, u64, u64, u64, int);
2983
2984         ref_root = btrfs_header_owner(buf);
2985         nritems = btrfs_header_nritems(buf);
2986         level = btrfs_header_level(buf);
2987
2988         if (!root->ref_cows && level == 0)
2989                 return 0;
2990
2991         if (inc)
2992                 process_func = btrfs_inc_extent_ref;
2993         else
2994                 process_func = btrfs_free_extent;
2995
2996         if (full_backref)
2997                 parent = buf->start;
2998         else
2999                 parent = 0;
3000
3001         for (i = 0; i < nritems; i++) {
3002                 if (level == 0) {
3003                         btrfs_item_key_to_cpu(buf, &key, i);
3004                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3005                                 continue;
3006                         fi = btrfs_item_ptr(buf, i,
3007                                             struct btrfs_file_extent_item);
3008                         if (btrfs_file_extent_type(buf, fi) ==
3009                             BTRFS_FILE_EXTENT_INLINE)
3010                                 continue;
3011                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3012                         if (bytenr == 0)
3013                                 continue;
3014
3015                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3016                         key.offset -= btrfs_file_extent_offset(buf, fi);
3017                         ret = process_func(trans, root, bytenr, num_bytes,
3018                                            parent, ref_root, key.objectid,
3019                                            key.offset, for_cow);
3020                         if (ret)
3021                                 goto fail;
3022                 } else {
3023                         bytenr = btrfs_node_blockptr(buf, i);
3024                         num_bytes = btrfs_level_size(root, level - 1);
3025                         ret = process_func(trans, root, bytenr, num_bytes,
3026                                            parent, ref_root, level - 1, 0,
3027                                            for_cow);
3028                         if (ret)
3029                                 goto fail;
3030                 }
3031         }
3032         return 0;
3033 fail:
3034         return ret;
3035 }
3036
3037 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3038                   struct extent_buffer *buf, int full_backref, int for_cow)
3039 {
3040         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
3041 }
3042
3043 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3044                   struct extent_buffer *buf, int full_backref, int for_cow)
3045 {
3046         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
3047 }
3048
3049 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3050                                  struct btrfs_root *root,
3051                                  struct btrfs_path *path,
3052                                  struct btrfs_block_group_cache *cache)
3053 {
3054         int ret;
3055         struct btrfs_root *extent_root = root->fs_info->extent_root;
3056         unsigned long bi;
3057         struct extent_buffer *leaf;
3058
3059         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3060         if (ret < 0)
3061                 goto fail;
3062         BUG_ON(ret); /* Corruption */
3063
3064         leaf = path->nodes[0];
3065         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3066         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3067         btrfs_mark_buffer_dirty(leaf);
3068         btrfs_release_path(path);
3069 fail:
3070         if (ret) {
3071                 btrfs_abort_transaction(trans, root, ret);
3072                 return ret;
3073         }
3074         return 0;
3075
3076 }
3077
3078 static struct btrfs_block_group_cache *
3079 next_block_group(struct btrfs_root *root,
3080                  struct btrfs_block_group_cache *cache)
3081 {
3082         struct rb_node *node;
3083         spin_lock(&root->fs_info->block_group_cache_lock);
3084         node = rb_next(&cache->cache_node);
3085         btrfs_put_block_group(cache);
3086         if (node) {
3087                 cache = rb_entry(node, struct btrfs_block_group_cache,
3088                                  cache_node);
3089                 btrfs_get_block_group(cache);
3090         } else
3091                 cache = NULL;
3092         spin_unlock(&root->fs_info->block_group_cache_lock);
3093         return cache;
3094 }
3095
3096 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3097                             struct btrfs_trans_handle *trans,
3098                             struct btrfs_path *path)
3099 {
3100         struct btrfs_root *root = block_group->fs_info->tree_root;
3101         struct inode *inode = NULL;
3102         u64 alloc_hint = 0;
3103         int dcs = BTRFS_DC_ERROR;
3104         int num_pages = 0;
3105         int retries = 0;
3106         int ret = 0;
3107
3108         /*
3109          * If this block group is smaller than 100 megs don't bother caching the
3110          * block group.
3111          */
3112         if (block_group->key.offset < (100 * 1024 * 1024)) {
3113                 spin_lock(&block_group->lock);
3114                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3115                 spin_unlock(&block_group->lock);
3116                 return 0;
3117         }
3118
3119 again:
3120         inode = lookup_free_space_inode(root, block_group, path);
3121         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3122                 ret = PTR_ERR(inode);
3123                 btrfs_release_path(path);
3124                 goto out;
3125         }
3126
3127         if (IS_ERR(inode)) {
3128                 BUG_ON(retries);
3129                 retries++;
3130
3131                 if (block_group->ro)
3132                         goto out_free;
3133
3134                 ret = create_free_space_inode(root, trans, block_group, path);
3135                 if (ret)
3136                         goto out_free;
3137                 goto again;
3138         }
3139
3140         /* We've already setup this transaction, go ahead and exit */
3141         if (block_group->cache_generation == trans->transid &&
3142             i_size_read(inode)) {
3143                 dcs = BTRFS_DC_SETUP;
3144                 goto out_put;
3145         }
3146
3147         /*
3148          * We want to set the generation to 0, that way if anything goes wrong
3149          * from here on out we know not to trust this cache when we load up next
3150          * time.
3151          */
3152         BTRFS_I(inode)->generation = 0;
3153         ret = btrfs_update_inode(trans, root, inode);
3154         WARN_ON(ret);
3155
3156         if (i_size_read(inode) > 0) {
3157                 ret = btrfs_check_trunc_cache_free_space(root,
3158                                         &root->fs_info->global_block_rsv);
3159                 if (ret)
3160                         goto out_put;
3161
3162                 ret = btrfs_truncate_free_space_cache(root, trans, path,
3163                                                       inode);
3164                 if (ret)
3165                         goto out_put;
3166         }
3167
3168         spin_lock(&block_group->lock);
3169         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3170             !btrfs_test_opt(root, SPACE_CACHE)) {
3171                 /*
3172                  * don't bother trying to write stuff out _if_
3173                  * a) we're not cached,
3174                  * b) we're with nospace_cache mount option.
3175                  */
3176                 dcs = BTRFS_DC_WRITTEN;
3177                 spin_unlock(&block_group->lock);
3178                 goto out_put;
3179         }
3180         spin_unlock(&block_group->lock);
3181
3182         /*
3183          * Try to preallocate enough space based on how big the block group is.
3184          * Keep in mind this has to include any pinned space which could end up
3185          * taking up quite a bit since it's not folded into the other space
3186          * cache.
3187          */
3188         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3189         if (!num_pages)
3190                 num_pages = 1;
3191
3192         num_pages *= 16;
3193         num_pages *= PAGE_CACHE_SIZE;
3194
3195         ret = btrfs_check_data_free_space(inode, num_pages);
3196         if (ret)
3197                 goto out_put;
3198
3199         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3200                                               num_pages, num_pages,
3201                                               &alloc_hint);
3202         if (!ret)
3203                 dcs = BTRFS_DC_SETUP;
3204         btrfs_free_reserved_data_space(inode, num_pages);
3205
3206 out_put:
3207         iput(inode);
3208 out_free:
3209         btrfs_release_path(path);
3210 out:
3211         spin_lock(&block_group->lock);
3212         if (!ret && dcs == BTRFS_DC_SETUP)
3213                 block_group->cache_generation = trans->transid;
3214         block_group->disk_cache_state = dcs;
3215         spin_unlock(&block_group->lock);
3216
3217         return ret;
3218 }
3219
3220 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3221                                    struct btrfs_root *root)
3222 {
3223         struct btrfs_block_group_cache *cache;
3224         int err = 0;
3225         struct btrfs_path *path;
3226         u64 last = 0;
3227
3228         path = btrfs_alloc_path();
3229         if (!path)
3230                 return -ENOMEM;
3231
3232 again:
3233         while (1) {
3234                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3235                 while (cache) {
3236                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3237                                 break;
3238                         cache = next_block_group(root, cache);
3239                 }
3240                 if (!cache) {
3241                         if (last == 0)
3242                                 break;
3243                         last = 0;
3244                         continue;
3245                 }
3246                 err = cache_save_setup(cache, trans, path);
3247                 last = cache->key.objectid + cache->key.offset;
3248                 btrfs_put_block_group(cache);
3249         }
3250
3251         while (1) {
3252                 if (last == 0) {
3253                         err = btrfs_run_delayed_refs(trans, root,
3254                                                      (unsigned long)-1);
3255                         if (err) /* File system offline */
3256                                 goto out;
3257                 }
3258
3259                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3260                 while (cache) {
3261                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3262                                 btrfs_put_block_group(cache);
3263                                 goto again;
3264                         }
3265
3266                         if (cache->dirty)
3267                                 break;
3268                         cache = next_block_group(root, cache);
3269                 }
3270                 if (!cache) {
3271                         if (last == 0)
3272                                 break;
3273                         last = 0;
3274                         continue;
3275                 }
3276
3277                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3278                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3279                 cache->dirty = 0;
3280                 last = cache->key.objectid + cache->key.offset;
3281
3282                 err = write_one_cache_group(trans, root, path, cache);
3283                 if (err) /* File system offline */
3284                         goto out;
3285
3286                 btrfs_put_block_group(cache);
3287         }
3288
3289         while (1) {
3290                 /*
3291                  * I don't think this is needed since we're just marking our
3292                  * preallocated extent as written, but just in case it can't
3293                  * hurt.
3294                  */
3295                 if (last == 0) {
3296                         err = btrfs_run_delayed_refs(trans, root,
3297                                                      (unsigned long)-1);
3298                         if (err) /* File system offline */
3299                                 goto out;
3300                 }
3301
3302                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3303                 while (cache) {
3304                         /*
3305                          * Really this shouldn't happen, but it could if we
3306                          * couldn't write the entire preallocated extent and
3307                          * splitting the extent resulted in a new block.
3308                          */
3309                         if (cache->dirty) {
3310                                 btrfs_put_block_group(cache);
3311                                 goto again;
3312                         }
3313                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3314                                 break;
3315                         cache = next_block_group(root, cache);
3316                 }
3317                 if (!cache) {
3318                         if (last == 0)
3319                                 break;
3320                         last = 0;
3321                         continue;
3322                 }
3323
3324                 err = btrfs_write_out_cache(root, trans, cache, path);
3325
3326                 /*
3327                  * If we didn't have an error then the cache state is still
3328                  * NEED_WRITE, so we can set it to WRITTEN.
3329                  */
3330                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3331                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3332                 last = cache->key.objectid + cache->key.offset;
3333                 btrfs_put_block_group(cache);
3334         }
3335 out:
3336
3337         btrfs_free_path(path);
3338         return err;
3339 }
3340
3341 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3342 {
3343         struct btrfs_block_group_cache *block_group;
3344         int readonly = 0;
3345
3346         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3347         if (!block_group || block_group->ro)
3348                 readonly = 1;
3349         if (block_group)
3350                 btrfs_put_block_group(block_group);
3351         return readonly;
3352 }
3353
3354 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3355                              u64 total_bytes, u64 bytes_used,
3356                              struct btrfs_space_info **space_info)
3357 {
3358         struct btrfs_space_info *found;
3359         int i;
3360         int factor;
3361         int ret;
3362
3363         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3364                      BTRFS_BLOCK_GROUP_RAID10))
3365                 factor = 2;
3366         else
3367                 factor = 1;
3368
3369         found = __find_space_info(info, flags);
3370         if (found) {
3371                 spin_lock(&found->lock);
3372                 found->total_bytes += total_bytes;
3373                 found->disk_total += total_bytes * factor;
3374                 found->bytes_used += bytes_used;
3375                 found->disk_used += bytes_used * factor;
3376                 found->full = 0;
3377                 spin_unlock(&found->lock);
3378                 *space_info = found;
3379                 return 0;
3380         }
3381         found = kzalloc(sizeof(*found), GFP_NOFS);
3382         if (!found)
3383                 return -ENOMEM;
3384
3385         ret = percpu_counter_init(&found->total_bytes_pinned, 0);
3386         if (ret) {
3387                 kfree(found);
3388                 return ret;
3389         }
3390
3391         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3392                 INIT_LIST_HEAD(&found->block_groups[i]);
3393         init_rwsem(&found->groups_sem);
3394         spin_lock_init(&found->lock);
3395         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3396         found->total_bytes = total_bytes;
3397         found->disk_total = total_bytes * factor;
3398         found->bytes_used = bytes_used;
3399         found->disk_used = bytes_used * factor;
3400         found->bytes_pinned = 0;
3401         found->bytes_reserved = 0;
3402         found->bytes_readonly = 0;
3403         found->bytes_may_use = 0;
3404         found->full = 0;
3405         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3406         found->chunk_alloc = 0;
3407         found->flush = 0;
3408         init_waitqueue_head(&found->wait);
3409         *space_info = found;
3410         list_add_rcu(&found->list, &info->space_info);
3411         if (flags & BTRFS_BLOCK_GROUP_DATA)
3412                 info->data_sinfo = found;
3413         return 0;
3414 }
3415
3416 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3417 {
3418         u64 extra_flags = chunk_to_extended(flags) &
3419                                 BTRFS_EXTENDED_PROFILE_MASK;
3420
3421         write_seqlock(&fs_info->profiles_lock);
3422         if (flags & BTRFS_BLOCK_GROUP_DATA)
3423                 fs_info->avail_data_alloc_bits |= extra_flags;
3424         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3425                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3426         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3427                 fs_info->avail_system_alloc_bits |= extra_flags;
3428         write_sequnlock(&fs_info->profiles_lock);
3429 }
3430
3431 /*
3432  * returns target flags in extended format or 0 if restripe for this
3433  * chunk_type is not in progress
3434  *
3435  * should be called with either volume_mutex or balance_lock held
3436  */
3437 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3438 {
3439         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3440         u64 target = 0;
3441
3442         if (!bctl)
3443                 return 0;
3444
3445         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3446             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3447                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3448         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3449                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3450                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3451         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3452                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3453                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3454         }
3455
3456         return target;
3457 }
3458
3459 /*
3460  * @flags: available profiles in extended format (see ctree.h)
3461  *
3462  * Returns reduced profile in chunk format.  If profile changing is in
3463  * progress (either running or paused) picks the target profile (if it's
3464  * already available), otherwise falls back to plain reducing.
3465  */
3466 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3467 {
3468         /*
3469          * we add in the count of missing devices because we want
3470          * to make sure that any RAID levels on a degraded FS
3471          * continue to be honored.
3472          */
3473         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3474                 root->fs_info->fs_devices->missing_devices;
3475         u64 target;
3476         u64 tmp;
3477
3478         /*
3479          * see if restripe for this chunk_type is in progress, if so
3480          * try to reduce to the target profile
3481          */
3482         spin_lock(&root->fs_info->balance_lock);
3483         target = get_restripe_target(root->fs_info, flags);
3484         if (target) {
3485                 /* pick target profile only if it's already available */
3486                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3487                         spin_unlock(&root->fs_info->balance_lock);
3488                         return extended_to_chunk(target);
3489                 }
3490         }
3491         spin_unlock(&root->fs_info->balance_lock);
3492
3493         /* First, mask out the RAID levels which aren't possible */
3494         if (num_devices == 1)
3495                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3496                            BTRFS_BLOCK_GROUP_RAID5);
3497         if (num_devices < 3)
3498                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3499         if (num_devices < 4)
3500                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3501
3502         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3503                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3504                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3505         flags &= ~tmp;
3506
3507         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3508                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3509         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3510                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3511         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3512                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3513         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3514                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3515         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3516                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3517
3518         return extended_to_chunk(flags | tmp);
3519 }
3520
3521 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3522 {
3523         unsigned seq;
3524
3525         do {
3526                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3527
3528                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3529                         flags |= root->fs_info->avail_data_alloc_bits;
3530                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3531                         flags |= root->fs_info->avail_system_alloc_bits;
3532                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3533                         flags |= root->fs_info->avail_metadata_alloc_bits;
3534         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3535
3536         return btrfs_reduce_alloc_profile(root, flags);
3537 }
3538
3539 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3540 {
3541         u64 flags;
3542         u64 ret;
3543
3544         if (data)
3545                 flags = BTRFS_BLOCK_GROUP_DATA;
3546         else if (root == root->fs_info->chunk_root)
3547                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3548         else
3549                 flags = BTRFS_BLOCK_GROUP_METADATA;
3550
3551         ret = get_alloc_profile(root, flags);
3552         return ret;
3553 }
3554
3555 /*
3556  * This will check the space that the inode allocates from to make sure we have
3557  * enough space for bytes.
3558  */
3559 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3560 {
3561         struct btrfs_space_info *data_sinfo;
3562         struct btrfs_root *root = BTRFS_I(inode)->root;
3563         struct btrfs_fs_info *fs_info = root->fs_info;
3564         u64 used;
3565         int ret = 0, committed = 0, alloc_chunk = 1;
3566
3567         /* make sure bytes are sectorsize aligned */
3568         bytes = ALIGN(bytes, root->sectorsize);
3569
3570         if (root == root->fs_info->tree_root ||
3571             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3572                 alloc_chunk = 0;
3573                 committed = 1;
3574         }
3575
3576         data_sinfo = fs_info->data_sinfo;
3577         if (!data_sinfo)
3578                 goto alloc;
3579
3580 again:
3581         /* make sure we have enough space to handle the data first */
3582         spin_lock(&data_sinfo->lock);
3583         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3584                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3585                 data_sinfo->bytes_may_use;
3586
3587         if (used + bytes > data_sinfo->total_bytes) {
3588                 struct btrfs_trans_handle *trans;
3589
3590                 /*
3591                  * if we don't have enough free bytes in this space then we need
3592                  * to alloc a new chunk.
3593                  */
3594                 if (!data_sinfo->full && alloc_chunk) {
3595                         u64 alloc_target;
3596
3597                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3598                         spin_unlock(&data_sinfo->lock);
3599 alloc:
3600                         alloc_target = btrfs_get_alloc_profile(root, 1);
3601                         trans = btrfs_join_transaction(root);
3602                         if (IS_ERR(trans))
3603                                 return PTR_ERR(trans);
3604
3605                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3606                                              alloc_target,
3607                                              CHUNK_ALLOC_NO_FORCE);
3608                         btrfs_end_transaction(trans, root);
3609                         if (ret < 0) {
3610                                 if (ret != -ENOSPC)
3611                                         return ret;
3612                                 else
3613                                         goto commit_trans;
3614                         }
3615
3616                         if (!data_sinfo)
3617                                 data_sinfo = fs_info->data_sinfo;
3618
3619                         goto again;
3620                 }
3621
3622                 /*
3623                  * If we don't have enough pinned space to deal with this
3624                  * allocation don't bother committing the transaction.
3625                  */
3626                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
3627                                            bytes) < 0)
3628                         committed = 1;
3629                 spin_unlock(&data_sinfo->lock);
3630
3631                 /* commit the current transaction and try again */
3632 commit_trans:
3633                 if (!committed &&
3634                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3635                         committed = 1;
3636
3637                         trans = btrfs_join_transaction(root);
3638                         if (IS_ERR(trans))
3639                                 return PTR_ERR(trans);
3640                         ret = btrfs_commit_transaction(trans, root);
3641                         if (ret)
3642                                 return ret;
3643                         goto again;
3644                 }
3645
3646                 return -ENOSPC;
3647         }
3648         data_sinfo->bytes_may_use += bytes;
3649         trace_btrfs_space_reservation(root->fs_info, "space_info",
3650                                       data_sinfo->flags, bytes, 1);
3651         spin_unlock(&data_sinfo->lock);
3652
3653         return 0;
3654 }
3655
3656 /*
3657  * Called if we need to clear a data reservation for this inode.
3658  */
3659 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3660 {
3661         struct btrfs_root *root = BTRFS_I(inode)->root;
3662         struct btrfs_space_info *data_sinfo;
3663
3664         /* make sure bytes are sectorsize aligned */
3665         bytes = ALIGN(bytes, root->sectorsize);
3666
3667         data_sinfo = root->fs_info->data_sinfo;
3668         spin_lock(&data_sinfo->lock);
3669         data_sinfo->bytes_may_use -= bytes;
3670         trace_btrfs_space_reservation(root->fs_info, "space_info",
3671                                       data_sinfo->flags, bytes, 0);
3672         spin_unlock(&data_sinfo->lock);
3673 }
3674
3675 static void force_metadata_allocation(struct btrfs_fs_info *info)
3676 {
3677         struct list_head *head = &info->space_info;
3678         struct btrfs_space_info *found;
3679
3680         rcu_read_lock();
3681         list_for_each_entry_rcu(found, head, list) {
3682                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3683                         found->force_alloc = CHUNK_ALLOC_FORCE;
3684         }
3685         rcu_read_unlock();
3686 }
3687
3688 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3689 {
3690         return (global->size << 1);
3691 }
3692
3693 static int should_alloc_chunk(struct btrfs_root *root,
3694                               struct btrfs_space_info *sinfo, int force)
3695 {
3696         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3697         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3698         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3699         u64 thresh;
3700
3701         if (force == CHUNK_ALLOC_FORCE)
3702                 return 1;
3703
3704         /*
3705          * We need to take into account the global rsv because for all intents
3706          * and purposes it's used space.  Don't worry about locking the
3707          * global_rsv, it doesn't change except when the transaction commits.
3708          */
3709         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3710                 num_allocated += calc_global_rsv_need_space(global_rsv);
3711
3712         /*
3713          * in limited mode, we want to have some free space up to
3714          * about 1% of the FS size.
3715          */
3716         if (force == CHUNK_ALLOC_LIMITED) {
3717                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3718                 thresh = max_t(u64, 64 * 1024 * 1024,
3719                                div_factor_fine(thresh, 1));
3720
3721                 if (num_bytes - num_allocated < thresh)
3722                         return 1;
3723         }
3724
3725         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3726                 return 0;
3727         return 1;
3728 }
3729
3730 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3731 {
3732         u64 num_dev;
3733
3734         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3735                     BTRFS_BLOCK_GROUP_RAID0 |
3736                     BTRFS_BLOCK_GROUP_RAID5 |
3737                     BTRFS_BLOCK_GROUP_RAID6))
3738                 num_dev = root->fs_info->fs_devices->rw_devices;
3739         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3740                 num_dev = 2;
3741         else
3742                 num_dev = 1;    /* DUP or single */
3743
3744         /* metadata for updaing devices and chunk tree */
3745         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3746 }
3747
3748 static void check_system_chunk(struct btrfs_trans_handle *trans,
3749                                struct btrfs_root *root, u64 type)
3750 {
3751         struct btrfs_space_info *info;
3752         u64 left;
3753         u64 thresh;
3754
3755         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3756         spin_lock(&info->lock);
3757         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3758                 info->bytes_reserved - info->bytes_readonly;
3759         spin_unlock(&info->lock);
3760
3761         thresh = get_system_chunk_thresh(root, type);
3762         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3763                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3764                         left, thresh, type);
3765                 dump_space_info(info, 0, 0);
3766         }
3767
3768         if (left < thresh) {
3769                 u64 flags;
3770
3771                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3772                 btrfs_alloc_chunk(trans, root, flags);
3773         }
3774 }
3775
3776 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3777                           struct btrfs_root *extent_root, u64 flags, int force)
3778 {
3779         struct btrfs_space_info *space_info;
3780         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3781         int wait_for_alloc = 0;
3782         int ret = 0;
3783
3784         /* Don't re-enter if we're already allocating a chunk */
3785         if (trans->allocating_chunk)
3786                 return -ENOSPC;
3787
3788         space_info = __find_space_info(extent_root->fs_info, flags);
3789         if (!space_info) {
3790                 ret = update_space_info(extent_root->fs_info, flags,
3791                                         0, 0, &space_info);
3792                 BUG_ON(ret); /* -ENOMEM */
3793         }
3794         BUG_ON(!space_info); /* Logic error */
3795
3796 again:
3797         spin_lock(&space_info->lock);
3798         if (force < space_info->force_alloc)
3799                 force = space_info->force_alloc;
3800         if (space_info->full) {
3801                 spin_unlock(&space_info->lock);
3802                 return 0;
3803         }
3804
3805         if (!should_alloc_chunk(extent_root, space_info, force)) {
3806                 spin_unlock(&space_info->lock);
3807                 return 0;
3808         } else if (space_info->chunk_alloc) {
3809                 wait_for_alloc = 1;
3810         } else {
3811                 space_info->chunk_alloc = 1;
3812         }
3813
3814         spin_unlock(&space_info->lock);
3815
3816         mutex_lock(&fs_info->chunk_mutex);
3817
3818         /*
3819          * The chunk_mutex is held throughout the entirety of a chunk
3820          * allocation, so once we've acquired the chunk_mutex we know that the
3821          * other guy is done and we need to recheck and see if we should
3822          * allocate.
3823          */
3824         if (wait_for_alloc) {
3825                 mutex_unlock(&fs_info->chunk_mutex);
3826                 wait_for_alloc = 0;
3827                 goto again;
3828         }
3829
3830         trans->allocating_chunk = true;
3831
3832         /*
3833          * If we have mixed data/metadata chunks we want to make sure we keep
3834          * allocating mixed chunks instead of individual chunks.
3835          */
3836         if (btrfs_mixed_space_info(space_info))
3837                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3838
3839         /*
3840          * if we're doing a data chunk, go ahead and make sure that
3841          * we keep a reasonable number of metadata chunks allocated in the
3842          * FS as well.
3843          */
3844         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3845                 fs_info->data_chunk_allocations++;
3846                 if (!(fs_info->data_chunk_allocations %
3847                       fs_info->metadata_ratio))
3848                         force_metadata_allocation(fs_info);
3849         }
3850
3851         /*
3852          * Check if we have enough space in SYSTEM chunk because we may need
3853          * to update devices.
3854          */
3855         check_system_chunk(trans, extent_root, flags);
3856
3857         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3858         trans->allocating_chunk = false;
3859
3860         spin_lock(&space_info->lock);
3861         if (ret < 0 && ret != -ENOSPC)
3862                 goto out;
3863         if (ret)
3864                 space_info->full = 1;
3865         else
3866                 ret = 1;
3867
3868         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3869 out:
3870         space_info->chunk_alloc = 0;
3871         spin_unlock(&space_info->lock);
3872         mutex_unlock(&fs_info->chunk_mutex);
3873         return ret;
3874 }
3875
3876 static int can_overcommit(struct btrfs_root *root,
3877                           struct btrfs_space_info *space_info, u64 bytes,
3878                           enum btrfs_reserve_flush_enum flush)
3879 {
3880         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3881         u64 profile = btrfs_get_alloc_profile(root, 0);
3882         u64 space_size;
3883         u64 avail;
3884         u64 used;
3885         u64 to_add;
3886
3887         used = space_info->bytes_used + space_info->bytes_reserved +
3888                 space_info->bytes_pinned + space_info->bytes_readonly;
3889
3890         /*
3891          * We only want to allow over committing if we have lots of actual space
3892          * free, but if we don't have enough space to handle the global reserve
3893          * space then we could end up having a real enospc problem when trying
3894          * to allocate a chunk or some other such important allocation.
3895          */
3896         spin_lock(&global_rsv->lock);
3897         space_size = calc_global_rsv_need_space(global_rsv);
3898         spin_unlock(&global_rsv->lock);
3899         if (used + space_size >= space_info->total_bytes)
3900                 return 0;
3901
3902         used += space_info->bytes_may_use;
3903
3904         spin_lock(&root->fs_info->free_chunk_lock);
3905         avail = root->fs_info->free_chunk_space;
3906         spin_unlock(&root->fs_info->free_chunk_lock);
3907
3908         /*
3909          * If we have dup, raid1 or raid10 then only half of the free
3910          * space is actually useable.  For raid56, the space info used
3911          * doesn't include the parity drive, so we don't have to
3912          * change the math
3913          */
3914         if (profile & (BTRFS_BLOCK_GROUP_DUP |
3915                        BTRFS_BLOCK_GROUP_RAID1 |
3916                        BTRFS_BLOCK_GROUP_RAID10))
3917                 avail >>= 1;
3918
3919         to_add = space_info->total_bytes;
3920
3921         /*
3922          * If we aren't flushing all things, let us overcommit up to
3923          * 1/2th of the space. If we can flush, don't let us overcommit
3924          * too much, let it overcommit up to 1/8 of the space.
3925          */
3926         if (flush == BTRFS_RESERVE_FLUSH_ALL)
3927                 to_add >>= 3;
3928         else
3929                 to_add >>= 1;
3930
3931         /*
3932          * Limit the overcommit to the amount of free space we could possibly
3933          * allocate for chunks.
3934          */
3935         to_add = min(avail, to_add);
3936
3937         if (used + bytes < space_info->total_bytes + to_add)
3938                 return 1;
3939         return 0;
3940 }
3941
3942 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
3943                                          unsigned long nr_pages)
3944 {
3945         struct super_block *sb = root->fs_info->sb;
3946
3947         if (down_read_trylock(&sb->s_umount)) {
3948                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
3949                 up_read(&sb->s_umount);
3950         } else {
3951                 /*
3952                  * We needn't worry the filesystem going from r/w to r/o though
3953                  * we don't acquire ->s_umount mutex, because the filesystem
3954                  * should guarantee the delalloc inodes list be empty after
3955                  * the filesystem is readonly(all dirty pages are written to
3956                  * the disk).
3957                  */
3958                 btrfs_start_all_delalloc_inodes(root->fs_info, 0);
3959                 if (!current->journal_info)
3960                         btrfs_wait_all_ordered_extents(root->fs_info, 0);
3961         }
3962 }
3963
3964 /*
3965  * shrink metadata reservation for delalloc
3966  */
3967 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
3968                             bool wait_ordered)
3969 {
3970         struct btrfs_block_rsv *block_rsv;
3971         struct btrfs_space_info *space_info;
3972         struct btrfs_trans_handle *trans;
3973         u64 delalloc_bytes;
3974         u64 max_reclaim;
3975         long time_left;
3976         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3977         int loops = 0;
3978         enum btrfs_reserve_flush_enum flush;
3979
3980         trans = (struct btrfs_trans_handle *)current->journal_info;
3981         block_rsv = &root->fs_info->delalloc_block_rsv;
3982         space_info = block_rsv->space_info;
3983
3984         smp_mb();
3985         delalloc_bytes = percpu_counter_sum_positive(
3986                                                 &root->fs_info->delalloc_bytes);
3987         if (delalloc_bytes == 0) {
3988                 if (trans)
3989                         return;
3990                 btrfs_wait_all_ordered_extents(root->fs_info, 0);
3991                 return;
3992         }
3993
3994         while (delalloc_bytes && loops < 3) {
3995                 max_reclaim = min(delalloc_bytes, to_reclaim);
3996                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
3997                 btrfs_writeback_inodes_sb_nr(root, nr_pages);
3998                 /*
3999                  * We need to wait for the async pages to actually start before
4000                  * we do anything.
4001                  */
4002                 wait_event(root->fs_info->async_submit_wait,
4003                            !atomic_read(&root->fs_info->async_delalloc_pages));
4004
4005                 if (!trans)
4006                         flush = BTRFS_RESERVE_FLUSH_ALL;
4007                 else
4008                         flush = BTRFS_RESERVE_NO_FLUSH;
4009                 spin_lock(&space_info->lock);
4010                 if (can_overcommit(root, space_info, orig, flush)) {
4011                         spin_unlock(&space_info->lock);
4012                         break;
4013                 }
4014                 spin_unlock(&space_info->lock);
4015
4016                 loops++;
4017                 if (wait_ordered && !trans) {
4018                         btrfs_wait_all_ordered_extents(root->fs_info, 0);
4019                 } else {
4020                         time_left = schedule_timeout_killable(1);
4021                         if (time_left)
4022                                 break;
4023                 }
4024                 smp_mb();
4025                 delalloc_bytes = percpu_counter_sum_positive(
4026                                                 &root->fs_info->delalloc_bytes);
4027         }
4028 }
4029
4030 /**
4031  * maybe_commit_transaction - possibly commit the transaction if its ok to
4032  * @root - the root we're allocating for
4033  * @bytes - the number of bytes we want to reserve
4034  * @force - force the commit
4035  *
4036  * This will check to make sure that committing the transaction will actually
4037  * get us somewhere and then commit the transaction if it does.  Otherwise it
4038  * will return -ENOSPC.
4039  */
4040 static int may_commit_transaction(struct btrfs_root *root,
4041                                   struct btrfs_space_info *space_info,
4042                                   u64 bytes, int force)
4043 {
4044         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4045         struct btrfs_trans_handle *trans;
4046
4047         trans = (struct btrfs_trans_handle *)current->journal_info;
4048         if (trans)
4049                 return -EAGAIN;
4050
4051         if (force)
4052                 goto commit;
4053
4054         /* See if there is enough pinned space to make this reservation */
4055         spin_lock(&space_info->lock);
4056         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4057                                    bytes) >= 0) {
4058                 spin_unlock(&space_info->lock);
4059                 goto commit;
4060         }
4061         spin_unlock(&space_info->lock);
4062
4063         /*
4064          * See if there is some space in the delayed insertion reservation for
4065          * this reservation.
4066          */
4067         if (space_info != delayed_rsv->space_info)
4068                 return -ENOSPC;
4069
4070         spin_lock(&space_info->lock);
4071         spin_lock(&delayed_rsv->lock);
4072         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4073                                    bytes - delayed_rsv->size) >= 0) {
4074                 spin_unlock(&delayed_rsv->lock);
4075                 spin_unlock(&space_info->lock);
4076                 return -ENOSPC;
4077         }
4078         spin_unlock(&delayed_rsv->lock);
4079         spin_unlock(&space_info->lock);
4080
4081 commit:
4082         trans = btrfs_join_transaction(root);
4083         if (IS_ERR(trans))
4084                 return -ENOSPC;
4085
4086         return btrfs_commit_transaction(trans, root);
4087 }
4088
4089 enum flush_state {
4090         FLUSH_DELAYED_ITEMS_NR  =       1,
4091         FLUSH_DELAYED_ITEMS     =       2,
4092         FLUSH_DELALLOC          =       3,
4093         FLUSH_DELALLOC_WAIT     =       4,
4094         ALLOC_CHUNK             =       5,
4095         COMMIT_TRANS            =       6,
4096 };
4097
4098 static int flush_space(struct btrfs_root *root,
4099                        struct btrfs_space_info *space_info, u64 num_bytes,
4100                        u64 orig_bytes, int state)
4101 {
4102         struct btrfs_trans_handle *trans;
4103         int nr;
4104         int ret = 0;
4105
4106         switch (state) {
4107         case FLUSH_DELAYED_ITEMS_NR:
4108         case FLUSH_DELAYED_ITEMS:
4109                 if (state == FLUSH_DELAYED_ITEMS_NR) {
4110                         u64 bytes = btrfs_calc_trans_metadata_size(root, 1);
4111
4112                         nr = (int)div64_u64(num_bytes, bytes);
4113                         if (!nr)
4114                                 nr = 1;
4115                         nr *= 2;
4116                 } else {
4117                         nr = -1;
4118                 }
4119                 trans = btrfs_join_transaction(root);
4120                 if (IS_ERR(trans)) {
4121                         ret = PTR_ERR(trans);
4122                         break;
4123                 }
4124                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4125                 btrfs_end_transaction(trans, root);
4126                 break;
4127         case FLUSH_DELALLOC:
4128         case FLUSH_DELALLOC_WAIT:
4129                 shrink_delalloc(root, num_bytes, orig_bytes,
4130                                 state == FLUSH_DELALLOC_WAIT);
4131                 break;
4132         case ALLOC_CHUNK:
4133                 trans = btrfs_join_transaction(root);
4134                 if (IS_ERR(trans)) {
4135                         ret = PTR_ERR(trans);
4136                         break;
4137                 }
4138                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4139                                      btrfs_get_alloc_profile(root, 0),
4140                                      CHUNK_ALLOC_NO_FORCE);
4141                 btrfs_end_transaction(trans, root);
4142                 if (ret == -ENOSPC)
4143                         ret = 0;
4144                 break;
4145         case COMMIT_TRANS:
4146                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4147                 break;
4148         default:
4149                 ret = -ENOSPC;
4150                 break;
4151         }
4152
4153         return ret;
4154 }
4155 /**
4156  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4157  * @root - the root we're allocating for
4158  * @block_rsv - the block_rsv we're allocating for
4159  * @orig_bytes - the number of bytes we want
4160  * @flush - whether or not we can flush to make our reservation
4161  *
4162  * This will reserve orgi_bytes number of bytes from the space info associated
4163  * with the block_rsv.  If there is not enough space it will make an attempt to
4164  * flush out space to make room.  It will do this by flushing delalloc if
4165  * possible or committing the transaction.  If flush is 0 then no attempts to
4166  * regain reservations will be made and this will fail if there is not enough
4167  * space already.
4168  */
4169 static int reserve_metadata_bytes(struct btrfs_root *root,
4170                                   struct btrfs_block_rsv *block_rsv,
4171                                   u64 orig_bytes,
4172                                   enum btrfs_reserve_flush_enum flush)
4173 {
4174         struct btrfs_space_info *space_info = block_rsv->space_info;
4175         u64 used;
4176         u64 num_bytes = orig_bytes;
4177         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4178         int ret = 0;
4179         bool flushing = false;
4180
4181 again:
4182         ret = 0;
4183         spin_lock(&space_info->lock);
4184         /*
4185          * We only want to wait if somebody other than us is flushing and we
4186          * are actually allowed to flush all things.
4187          */
4188         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4189                space_info->flush) {
4190                 spin_unlock(&space_info->lock);
4191                 /*
4192                  * If we have a trans handle we can't wait because the flusher
4193                  * may have to commit the transaction, which would mean we would
4194                  * deadlock since we are waiting for the flusher to finish, but
4195                  * hold the current transaction open.
4196                  */
4197                 if (current->journal_info)
4198                         return -EAGAIN;
4199                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4200                 /* Must have been killed, return */
4201                 if (ret)
4202                         return -EINTR;
4203
4204                 spin_lock(&space_info->lock);
4205         }
4206
4207         ret = -ENOSPC;
4208         used = space_info->bytes_used + space_info->bytes_reserved +
4209                 space_info->bytes_pinned + space_info->bytes_readonly +
4210                 space_info->bytes_may_use;
4211
4212         /*
4213          * The idea here is that we've not already over-reserved the block group
4214          * then we can go ahead and save our reservation first and then start
4215          * flushing if we need to.  Otherwise if we've already overcommitted
4216          * lets start flushing stuff first and then come back and try to make
4217          * our reservation.
4218          */
4219         if (used <= space_info->total_bytes) {
4220                 if (used + orig_bytes <= space_info->total_bytes) {
4221                         space_info->bytes_may_use += orig_bytes;
4222                         trace_btrfs_space_reservation(root->fs_info,
4223                                 "space_info", space_info->flags, orig_bytes, 1);
4224                         ret = 0;
4225                 } else {
4226                         /*
4227                          * Ok set num_bytes to orig_bytes since we aren't
4228                          * overocmmitted, this way we only try and reclaim what
4229                          * we need.
4230                          */
4231                         num_bytes = orig_bytes;
4232                 }
4233         } else {
4234                 /*
4235                  * Ok we're over committed, set num_bytes to the overcommitted
4236                  * amount plus the amount of bytes that we need for this
4237                  * reservation.
4238                  */
4239                 num_bytes = used - space_info->total_bytes +
4240                         (orig_bytes * 2);
4241         }
4242
4243         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4244                 space_info->bytes_may_use += orig_bytes;
4245                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4246                                               space_info->flags, orig_bytes,
4247                                               1);
4248                 ret = 0;
4249         }
4250
4251         /*
4252          * Couldn't make our reservation, save our place so while we're trying
4253          * to reclaim space we can actually use it instead of somebody else
4254          * stealing it from us.
4255          *
4256          * We make the other tasks wait for the flush only when we can flush
4257          * all things.
4258          */
4259         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4260                 flushing = true;
4261                 space_info->flush = 1;
4262         }
4263
4264         spin_unlock(&space_info->lock);
4265
4266         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4267                 goto out;
4268
4269         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4270                           flush_state);
4271         flush_state++;
4272
4273         /*
4274          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4275          * would happen. So skip delalloc flush.
4276          */
4277         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4278             (flush_state == FLUSH_DELALLOC ||
4279              flush_state == FLUSH_DELALLOC_WAIT))
4280                 flush_state = ALLOC_CHUNK;
4281
4282         if (!ret)
4283                 goto again;
4284         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4285                  flush_state < COMMIT_TRANS)
4286                 goto again;
4287         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4288                  flush_state <= COMMIT_TRANS)
4289                 goto again;
4290
4291 out:
4292         if (ret == -ENOSPC &&
4293             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4294                 struct btrfs_block_rsv *global_rsv =
4295                         &root->fs_info->global_block_rsv;
4296
4297                 if (block_rsv != global_rsv &&
4298                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4299                         ret = 0;
4300         }
4301         if (flushing) {
4302                 spin_lock(&space_info->lock);
4303                 space_info->flush = 0;
4304                 wake_up_all(&space_info->wait);
4305                 spin_unlock(&space_info->lock);
4306         }
4307         return ret;
4308 }
4309
4310 static struct btrfs_block_rsv *get_block_rsv(
4311                                         const struct btrfs_trans_handle *trans,
4312                                         const struct btrfs_root *root)
4313 {
4314         struct btrfs_block_rsv *block_rsv = NULL;
4315
4316         if (root->ref_cows)
4317                 block_rsv = trans->block_rsv;
4318
4319         if (root == root->fs_info->csum_root && trans->adding_csums)
4320                 block_rsv = trans->block_rsv;
4321
4322         if (!block_rsv)
4323                 block_rsv = root->block_rsv;
4324
4325         if (!block_rsv)
4326                 block_rsv = &root->fs_info->empty_block_rsv;
4327
4328         return block_rsv;
4329 }
4330
4331 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4332                                u64 num_bytes)
4333 {
4334         int ret = -ENOSPC;
4335         spin_lock(&block_rsv->lock);
4336         if (block_rsv->reserved >= num_bytes) {
4337                 block_rsv->reserved -= num_bytes;
4338                 if (block_rsv->reserved < block_rsv->size)
4339                         block_rsv->full = 0;
4340                 ret = 0;
4341         }
4342         spin_unlock(&block_rsv->lock);
4343         return ret;
4344 }
4345
4346 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4347                                 u64 num_bytes, int update_size)
4348 {
4349         spin_lock(&block_rsv->lock);
4350         block_rsv->reserved += num_bytes;
4351         if (update_size)
4352                 block_rsv->size += num_bytes;
4353         else if (block_rsv->reserved >= block_rsv->size)
4354                 block_rsv->full = 1;
4355         spin_unlock(&block_rsv->lock);
4356 }
4357
4358 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4359                              struct btrfs_block_rsv *dest, u64 num_bytes,
4360                              int min_factor)
4361 {
4362         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4363         u64 min_bytes;
4364
4365         if (global_rsv->space_info != dest->space_info)
4366                 return -ENOSPC;
4367
4368         spin_lock(&global_rsv->lock);
4369         min_bytes = div_factor(global_rsv->size, min_factor);
4370         if (global_rsv->reserved < min_bytes + num_bytes) {
4371                 spin_unlock(&global_rsv->lock);
4372                 return -ENOSPC;
4373         }
4374         global_rsv->reserved -= num_bytes;
4375         if (global_rsv->reserved < global_rsv->size)
4376                 global_rsv->full = 0;
4377         spin_unlock(&global_rsv->lock);
4378
4379         block_rsv_add_bytes(dest, num_bytes, 1);
4380         return 0;
4381 }
4382
4383 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4384                                     struct btrfs_block_rsv *block_rsv,
4385                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4386 {
4387         struct btrfs_space_info *space_info = block_rsv->space_info;
4388
4389         spin_lock(&block_rsv->lock);
4390         if (num_bytes == (u64)-1)
4391                 num_bytes = block_rsv->size;
4392         block_rsv->size -= num_bytes;
4393         if (block_rsv->reserved >= block_rsv->size) {
4394                 num_bytes = block_rsv->reserved - block_rsv->size;
4395                 block_rsv->reserved = block_rsv->size;
4396                 block_rsv->full = 1;
4397         } else {
4398                 num_bytes = 0;
4399         }
4400         spin_unlock(&block_rsv->lock);
4401
4402         if (num_bytes > 0) {
4403                 if (dest) {
4404                         spin_lock(&dest->lock);
4405                         if (!dest->full) {
4406                                 u64 bytes_to_add;
4407
4408                                 bytes_to_add = dest->size - dest->reserved;
4409                                 bytes_to_add = min(num_bytes, bytes_to_add);
4410                                 dest->reserved += bytes_to_add;
4411                                 if (dest->reserved >= dest->size)
4412                                         dest->full = 1;
4413                                 num_bytes -= bytes_to_add;
4414                         }
4415                         spin_unlock(&dest->lock);
4416                 }
4417                 if (num_bytes) {
4418                         spin_lock(&space_info->lock);
4419                         space_info->bytes_may_use -= num_bytes;
4420                         trace_btrfs_space_reservation(fs_info, "space_info",
4421                                         space_info->flags, num_bytes, 0);
4422                         space_info->reservation_progress++;
4423                         spin_unlock(&space_info->lock);
4424                 }
4425         }
4426 }
4427
4428 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4429                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4430 {
4431         int ret;
4432
4433         ret = block_rsv_use_bytes(src, num_bytes);
4434         if (ret)
4435                 return ret;
4436
4437         block_rsv_add_bytes(dst, num_bytes, 1);
4438         return 0;
4439 }
4440
4441 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4442 {
4443         memset(rsv, 0, sizeof(*rsv));
4444         spin_lock_init(&rsv->lock);
4445         rsv->type = type;
4446 }
4447
4448 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4449                                               unsigned short type)
4450 {
4451         struct btrfs_block_rsv *block_rsv;
4452         struct btrfs_fs_info *fs_info = root->fs_info;
4453
4454         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4455         if (!block_rsv)
4456                 return NULL;
4457
4458         btrfs_init_block_rsv(block_rsv, type);
4459         block_rsv->space_info = __find_space_info(fs_info,
4460                                                   BTRFS_BLOCK_GROUP_METADATA);
4461         return block_rsv;
4462 }
4463
4464 void btrfs_free_block_rsv(struct btrfs_root *root,
4465                           struct btrfs_block_rsv *rsv)
4466 {
4467         if (!rsv)
4468                 return;
4469         btrfs_block_rsv_release(root, rsv, (u64)-1);
4470         kfree(rsv);
4471 }
4472
4473 int btrfs_block_rsv_add(struct btrfs_root *root,
4474                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4475                         enum btrfs_reserve_flush_enum flush)
4476 {
4477         int ret;
4478
4479         if (num_bytes == 0)
4480                 return 0;
4481
4482         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4483         if (!ret) {
4484                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4485                 return 0;
4486         }
4487
4488         return ret;
4489 }
4490
4491 int btrfs_block_rsv_check(struct btrfs_root *root,
4492                           struct btrfs_block_rsv *block_rsv, int min_factor)
4493 {
4494         u64 num_bytes = 0;
4495         int ret = -ENOSPC;
4496
4497         if (!block_rsv)
4498                 return 0;
4499
4500         spin_lock(&block_rsv->lock);
4501         num_bytes = div_factor(block_rsv->size, min_factor);
4502         if (block_rsv->reserved >= num_bytes)
4503                 ret = 0;
4504         spin_unlock(&block_rsv->lock);
4505
4506         return ret;
4507 }
4508
4509 int btrfs_block_rsv_refill(struct btrfs_root *root,
4510                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4511                            enum btrfs_reserve_flush_enum flush)
4512 {
4513         u64 num_bytes = 0;
4514         int ret = -ENOSPC;
4515
4516         if (!block_rsv)
4517                 return 0;
4518
4519         spin_lock(&block_rsv->lock);
4520         num_bytes = min_reserved;
4521         if (block_rsv->reserved >= num_bytes)
4522                 ret = 0;
4523         else
4524                 num_bytes -= block_rsv->reserved;
4525         spin_unlock(&block_rsv->lock);
4526
4527         if (!ret)
4528                 return 0;
4529
4530         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4531         if (!ret) {
4532                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4533                 return 0;
4534         }
4535
4536         return ret;
4537 }
4538
4539 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4540                             struct btrfs_block_rsv *dst_rsv,
4541                             u64 num_bytes)
4542 {
4543         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4544 }
4545
4546 void btrfs_block_rsv_release(struct btrfs_root *root,
4547                              struct btrfs_block_rsv *block_rsv,
4548                              u64 num_bytes)
4549 {
4550         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4551         if (global_rsv->full || global_rsv == block_rsv ||
4552             block_rsv->space_info != global_rsv->space_info)
4553                 global_rsv = NULL;
4554         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4555                                 num_bytes);
4556 }
4557
4558 /*
4559  * helper to calculate size of global block reservation.
4560  * the desired value is sum of space used by extent tree,
4561  * checksum tree and root tree
4562  */
4563 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4564 {
4565         struct btrfs_space_info *sinfo;
4566         u64 num_bytes;
4567         u64 meta_used;
4568         u64 data_used;
4569         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4570
4571         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4572         spin_lock(&sinfo->lock);
4573         data_used = sinfo->bytes_used;
4574         spin_unlock(&sinfo->lock);
4575
4576         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4577         spin_lock(&sinfo->lock);
4578         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4579                 data_used = 0;
4580         meta_used = sinfo->bytes_used;
4581         spin_unlock(&sinfo->lock);
4582
4583         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4584                     csum_size * 2;
4585         num_bytes += div64_u64(data_used + meta_used, 50);
4586
4587         if (num_bytes * 3 > meta_used)
4588                 num_bytes = div64_u64(meta_used, 3);
4589
4590         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4591 }
4592
4593 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4594 {
4595         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4596         struct btrfs_space_info *sinfo = block_rsv->space_info;
4597         u64 num_bytes;
4598
4599         num_bytes = calc_global_metadata_size(fs_info);
4600
4601         spin_lock(&sinfo->lock);
4602         spin_lock(&block_rsv->lock);
4603
4604         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4605
4606         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4607                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4608                     sinfo->bytes_may_use;
4609
4610         if (sinfo->total_bytes > num_bytes) {
4611                 num_bytes = sinfo->total_bytes - num_bytes;
4612                 block_rsv->reserved += num_bytes;
4613                 sinfo->bytes_may_use += num_bytes;
4614                 trace_btrfs_space_reservation(fs_info, "space_info",
4615                                       sinfo->flags, num_bytes, 1);
4616         }
4617
4618         if (block_rsv->reserved >= block_rsv->size) {
4619                 num_bytes = block_rsv->reserved - block_rsv->size;
4620                 sinfo->bytes_may_use -= num_bytes;
4621                 trace_btrfs_space_reservation(fs_info, "space_info",
4622                                       sinfo->flags, num_bytes, 0);
4623                 sinfo->reservation_progress++;
4624                 block_rsv->reserved = block_rsv->size;
4625                 block_rsv->full = 1;
4626         }
4627
4628         spin_unlock(&block_rsv->lock);
4629         spin_unlock(&sinfo->lock);
4630 }
4631
4632 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4633 {
4634         struct btrfs_space_info *space_info;
4635
4636         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4637         fs_info->chunk_block_rsv.space_info = space_info;
4638
4639         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4640         fs_info->global_block_rsv.space_info = space_info;
4641         fs_info->delalloc_block_rsv.space_info = space_info;
4642         fs_info->trans_block_rsv.space_info = space_info;
4643         fs_info->empty_block_rsv.space_info = space_info;
4644         fs_info->delayed_block_rsv.space_info = space_info;
4645
4646         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4647         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4648         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4649         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4650         if (fs_info->quota_root)
4651                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4652         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4653
4654         update_global_block_rsv(fs_info);
4655 }
4656
4657 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4658 {
4659         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4660                                 (u64)-1);
4661         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4662         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4663         WARN_ON(fs_info->trans_block_rsv.size > 0);
4664         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4665         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4666         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4667         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4668         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4669 }
4670
4671 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4672                                   struct btrfs_root *root)
4673 {
4674         if (!trans->block_rsv)
4675                 return;
4676
4677         if (!trans->bytes_reserved)
4678                 return;
4679
4680         trace_btrfs_space_reservation(root->fs_info, "transaction",
4681                                       trans->transid, trans->bytes_reserved, 0);
4682         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4683         trans->bytes_reserved = 0;
4684 }
4685
4686 /* Can only return 0 or -ENOSPC */
4687 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4688                                   struct inode *inode)
4689 {
4690         struct btrfs_root *root = BTRFS_I(inode)->root;
4691         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4692         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4693
4694         /*
4695          * We need to hold space in order to delete our orphan item once we've
4696          * added it, so this takes the reservation so we can release it later
4697          * when we are truly done with the orphan item.
4698          */
4699         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4700         trace_btrfs_space_reservation(root->fs_info, "orphan",
4701                                       btrfs_ino(inode), num_bytes, 1);
4702         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4703 }
4704
4705 void btrfs_orphan_release_metadata(struct inode *inode)
4706 {
4707         struct btrfs_root *root = BTRFS_I(inode)->root;
4708         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4709         trace_btrfs_space_reservation(root->fs_info, "orphan",
4710                                       btrfs_ino(inode), num_bytes, 0);
4711         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4712 }
4713
4714 /*
4715  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4716  * root: the root of the parent directory
4717  * rsv: block reservation
4718  * items: the number of items that we need do reservation
4719  * qgroup_reserved: used to return the reserved size in qgroup
4720  *
4721  * This function is used to reserve the space for snapshot/subvolume
4722  * creation and deletion. Those operations are different with the
4723  * common file/directory operations, they change two fs/file trees
4724  * and root tree, the number of items that the qgroup reserves is
4725  * different with the free space reservation. So we can not use
4726  * the space reseravtion mechanism in start_transaction().
4727  */
4728 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4729                                      struct btrfs_block_rsv *rsv,
4730                                      int items,
4731                                      u64 *qgroup_reserved)
4732 {
4733         u64 num_bytes;
4734         int ret;
4735
4736         if (root->fs_info->quota_enabled) {
4737                 /* One for parent inode, two for dir entries */
4738                 num_bytes = 3 * root->leafsize;
4739                 ret = btrfs_qgroup_reserve(root, num_bytes);
4740                 if (ret)
4741                         return ret;
4742         } else {
4743                 num_bytes = 0;
4744         }
4745
4746         *qgroup_reserved = num_bytes;
4747
4748         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4749         rsv->space_info = __find_space_info(root->fs_info,
4750                                             BTRFS_BLOCK_GROUP_METADATA);
4751         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4752                                   BTRFS_RESERVE_FLUSH_ALL);
4753         if (ret) {
4754                 if (*qgroup_reserved)
4755                         btrfs_qgroup_free(root, *qgroup_reserved);
4756         }
4757
4758         return ret;
4759 }
4760
4761 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4762                                       struct btrfs_block_rsv *rsv,
4763                                       u64 qgroup_reserved)
4764 {
4765         btrfs_block_rsv_release(root, rsv, (u64)-1);
4766         if (qgroup_reserved)
4767                 btrfs_qgroup_free(root, qgroup_reserved);
4768 }
4769
4770 /**
4771  * drop_outstanding_extent - drop an outstanding extent
4772  * @inode: the inode we're dropping the extent for
4773  *
4774  * This is called when we are freeing up an outstanding extent, either called
4775  * after an error or after an extent is written.  This will return the number of
4776  * reserved extents that need to be freed.  This must be called with
4777  * BTRFS_I(inode)->lock held.
4778  */
4779 static unsigned drop_outstanding_extent(struct inode *inode)
4780 {
4781         unsigned drop_inode_space = 0;
4782         unsigned dropped_extents = 0;
4783
4784         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4785         BTRFS_I(inode)->outstanding_extents--;
4786
4787         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4788             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4789                                &BTRFS_I(inode)->runtime_flags))
4790                 drop_inode_space = 1;
4791
4792         /*
4793          * If we have more or the same amount of outsanding extents than we have
4794          * reserved then we need to leave the reserved extents count alone.
4795          */
4796         if (BTRFS_I(inode)->outstanding_extents >=
4797             BTRFS_I(inode)->reserved_extents)
4798                 return drop_inode_space;
4799
4800         dropped_extents = BTRFS_I(inode)->reserved_extents -
4801                 BTRFS_I(inode)->outstanding_extents;
4802         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4803         return dropped_extents + drop_inode_space;
4804 }
4805
4806 /**
4807  * calc_csum_metadata_size - return the amount of metada space that must be
4808  *      reserved/free'd for the given bytes.
4809  * @inode: the inode we're manipulating
4810  * @num_bytes: the number of bytes in question
4811  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4812  *
4813  * This adjusts the number of csum_bytes in the inode and then returns the
4814  * correct amount of metadata that must either be reserved or freed.  We
4815  * calculate how many checksums we can fit into one leaf and then divide the
4816  * number of bytes that will need to be checksumed by this value to figure out
4817  * how many checksums will be required.  If we are adding bytes then the number
4818  * may go up and we will return the number of additional bytes that must be
4819  * reserved.  If it is going down we will return the number of bytes that must
4820  * be freed.
4821  *
4822  * This must be called with BTRFS_I(inode)->lock held.
4823  */
4824 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4825                                    int reserve)
4826 {
4827         struct btrfs_root *root = BTRFS_I(inode)->root;
4828         u64 csum_size;
4829         int num_csums_per_leaf;
4830         int num_csums;
4831         int old_csums;
4832
4833         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4834             BTRFS_I(inode)->csum_bytes == 0)
4835                 return 0;
4836
4837         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4838         if (reserve)
4839                 BTRFS_I(inode)->csum_bytes += num_bytes;
4840         else
4841                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4842         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4843         num_csums_per_leaf = (int)div64_u64(csum_size,
4844                                             sizeof(struct btrfs_csum_item) +
4845                                             sizeof(struct btrfs_disk_key));
4846         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4847         num_csums = num_csums + num_csums_per_leaf - 1;
4848         num_csums = num_csums / num_csums_per_leaf;
4849
4850         old_csums = old_csums + num_csums_per_leaf - 1;
4851         old_csums = old_csums / num_csums_per_leaf;
4852
4853         /* No change, no need to reserve more */
4854         if (old_csums == num_csums)
4855                 return 0;
4856
4857         if (reserve)
4858                 return btrfs_calc_trans_metadata_size(root,
4859                                                       num_csums - old_csums);
4860
4861         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4862 }
4863
4864 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4865 {
4866         struct btrfs_root *root = BTRFS_I(inode)->root;
4867         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4868         u64 to_reserve = 0;
4869         u64 csum_bytes;
4870         unsigned nr_extents = 0;
4871         int extra_reserve = 0;
4872         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
4873         int ret = 0;
4874         bool delalloc_lock = true;
4875         u64 to_free = 0;
4876         unsigned dropped;
4877
4878         /* If we are a free space inode we need to not flush since we will be in
4879          * the middle of a transaction commit.  We also don't need the delalloc
4880          * mutex since we won't race with anybody.  We need this mostly to make
4881          * lockdep shut its filthy mouth.
4882          */
4883         if (btrfs_is_free_space_inode(inode)) {
4884                 flush = BTRFS_RESERVE_NO_FLUSH;
4885                 delalloc_lock = false;
4886         }
4887
4888         if (flush != BTRFS_RESERVE_NO_FLUSH &&
4889             btrfs_transaction_in_commit(root->fs_info))
4890                 schedule_timeout(1);
4891
4892         if (delalloc_lock)
4893                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4894
4895         num_bytes = ALIGN(num_bytes, root->sectorsize);
4896
4897         spin_lock(&BTRFS_I(inode)->lock);
4898         BTRFS_I(inode)->outstanding_extents++;
4899
4900         if (BTRFS_I(inode)->outstanding_extents >
4901             BTRFS_I(inode)->reserved_extents)
4902                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4903                         BTRFS_I(inode)->reserved_extents;
4904
4905         /*
4906          * Add an item to reserve for updating the inode when we complete the
4907          * delalloc io.
4908          */
4909         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4910                       &BTRFS_I(inode)->runtime_flags)) {
4911                 nr_extents++;
4912                 extra_reserve = 1;
4913         }
4914
4915         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4916         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4917         csum_bytes = BTRFS_I(inode)->csum_bytes;
4918         spin_unlock(&BTRFS_I(inode)->lock);
4919
4920         if (root->fs_info->quota_enabled) {
4921                 ret = btrfs_qgroup_reserve(root, num_bytes +
4922                                            nr_extents * root->leafsize);
4923                 if (ret)
4924                         goto out_fail;
4925         }
4926
4927         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4928         if (unlikely(ret)) {
4929                 if (root->fs_info->quota_enabled)
4930                         btrfs_qgroup_free(root, num_bytes +
4931                                                 nr_extents * root->leafsize);
4932                 goto out_fail;
4933         }
4934
4935         spin_lock(&BTRFS_I(inode)->lock);
4936         if (extra_reserve) {
4937                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4938                         &BTRFS_I(inode)->runtime_flags);
4939                 nr_extents--;
4940         }
4941         BTRFS_I(inode)->reserved_extents += nr_extents;
4942         spin_unlock(&BTRFS_I(inode)->lock);
4943
4944         if (delalloc_lock)
4945                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4946
4947         if (to_reserve)
4948                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4949                                               btrfs_ino(inode), to_reserve, 1);
4950         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4951
4952         return 0;
4953
4954 out_fail:
4955         spin_lock(&BTRFS_I(inode)->lock);
4956         dropped = drop_outstanding_extent(inode);
4957         /*
4958          * If the inodes csum_bytes is the same as the original
4959          * csum_bytes then we know we haven't raced with any free()ers
4960          * so we can just reduce our inodes csum bytes and carry on.
4961          */
4962         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
4963                 calc_csum_metadata_size(inode, num_bytes, 0);
4964         } else {
4965                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
4966                 u64 bytes;
4967
4968                 /*
4969                  * This is tricky, but first we need to figure out how much we
4970                  * free'd from any free-ers that occured during this
4971                  * reservation, so we reset ->csum_bytes to the csum_bytes
4972                  * before we dropped our lock, and then call the free for the
4973                  * number of bytes that were freed while we were trying our
4974                  * reservation.
4975                  */
4976                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
4977                 BTRFS_I(inode)->csum_bytes = csum_bytes;
4978                 to_free = calc_csum_metadata_size(inode, bytes, 0);
4979
4980
4981                 /*
4982                  * Now we need to see how much we would have freed had we not
4983                  * been making this reservation and our ->csum_bytes were not
4984                  * artificially inflated.
4985                  */
4986                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
4987                 bytes = csum_bytes - orig_csum_bytes;
4988                 bytes = calc_csum_metadata_size(inode, bytes, 0);
4989
4990                 /*
4991                  * Now reset ->csum_bytes to what it should be.  If bytes is
4992                  * more than to_free then we would have free'd more space had we
4993                  * not had an artificially high ->csum_bytes, so we need to free
4994                  * the remainder.  If bytes is the same or less then we don't
4995                  * need to do anything, the other free-ers did the correct
4996                  * thing.
4997                  */
4998                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
4999                 if (bytes > to_free)
5000                         to_free = bytes - to_free;
5001                 else
5002                         to_free = 0;
5003         }
5004         spin_unlock(&BTRFS_I(inode)->lock);
5005         if (dropped)
5006                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5007
5008         if (to_free) {
5009                 btrfs_block_rsv_release(root, block_rsv, to_free);
5010                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5011                                               btrfs_ino(inode), to_free, 0);
5012         }
5013         if (delalloc_lock)
5014                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5015         return ret;
5016 }
5017
5018 /**
5019  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5020  * @inode: the inode to release the reservation for
5021  * @num_bytes: the number of bytes we're releasing
5022  *
5023  * This will release the metadata reservation for an inode.  This can be called
5024  * once we complete IO for a given set of bytes to release their metadata
5025  * reservations.
5026  */
5027 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5028 {
5029         struct btrfs_root *root = BTRFS_I(inode)->root;
5030         u64 to_free = 0;
5031         unsigned dropped;
5032
5033         num_bytes = ALIGN(num_bytes, root->sectorsize);
5034         spin_lock(&BTRFS_I(inode)->lock);
5035         dropped = drop_outstanding_extent(inode);
5036
5037         if (num_bytes)
5038                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5039         spin_unlock(&BTRFS_I(inode)->lock);
5040         if (dropped > 0)
5041                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5042
5043         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5044                                       btrfs_ino(inode), to_free, 0);
5045         if (root->fs_info->quota_enabled) {
5046                 btrfs_qgroup_free(root, num_bytes +
5047                                         dropped * root->leafsize);
5048         }
5049
5050         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5051                                 to_free);
5052 }
5053
5054 /**
5055  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5056  * @inode: inode we're writing to
5057  * @num_bytes: the number of bytes we want to allocate
5058  *
5059  * This will do the following things
5060  *
5061  * o reserve space in the data space info for num_bytes
5062  * o reserve space in the metadata space info based on number of outstanding
5063  *   extents and how much csums will be needed
5064  * o add to the inodes ->delalloc_bytes
5065  * o add it to the fs_info's delalloc inodes list.
5066  *
5067  * This will return 0 for success and -ENOSPC if there is no space left.
5068  */
5069 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5070 {
5071         int ret;
5072
5073         ret = btrfs_check_data_free_space(inode, num_bytes);
5074         if (ret)
5075                 return ret;
5076
5077         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5078         if (ret) {
5079                 btrfs_free_reserved_data_space(inode, num_bytes);
5080                 return ret;
5081         }
5082
5083         return 0;
5084 }
5085
5086 /**
5087  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5088  * @inode: inode we're releasing space for
5089  * @num_bytes: the number of bytes we want to free up
5090  *
5091  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5092  * called in the case that we don't need the metadata AND data reservations
5093  * anymore.  So if there is an error or we insert an inline extent.
5094  *
5095  * This function will release the metadata space that was not used and will
5096  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5097  * list if there are no delalloc bytes left.
5098  */
5099 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5100 {
5101         btrfs_delalloc_release_metadata(inode, num_bytes);
5102         btrfs_free_reserved_data_space(inode, num_bytes);
5103 }
5104
5105 static int update_block_group(struct btrfs_root *root,
5106                               u64 bytenr, u64 num_bytes, int alloc)
5107 {
5108         struct btrfs_block_group_cache *cache = NULL;
5109         struct btrfs_fs_info *info = root->fs_info;
5110         u64 total = num_bytes;
5111         u64 old_val;
5112         u64 byte_in_group;
5113         int factor;
5114
5115         /* block accounting for super block */
5116         spin_lock(&info->delalloc_root_lock);
5117         old_val = btrfs_super_bytes_used(info->super_copy);
5118         if (alloc)
5119                 old_val += num_bytes;
5120         else
5121                 old_val -= num_bytes;
5122         btrfs_set_super_bytes_used(info->super_copy, old_val);
5123         spin_unlock(&info->delalloc_root_lock);
5124
5125         while (total) {
5126                 cache = btrfs_lookup_block_group(info, bytenr);
5127                 if (!cache)
5128                         return -ENOENT;
5129                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5130                                     BTRFS_BLOCK_GROUP_RAID1 |
5131                                     BTRFS_BLOCK_GROUP_RAID10))
5132                         factor = 2;
5133                 else
5134                         factor = 1;
5135                 /*
5136                  * If this block group has free space cache written out, we
5137                  * need to make sure to load it if we are removing space.  This
5138                  * is because we need the unpinning stage to actually add the
5139                  * space back to the block group, otherwise we will leak space.
5140                  */
5141                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5142                         cache_block_group(cache, 1);
5143
5144                 byte_in_group = bytenr - cache->key.objectid;
5145                 WARN_ON(byte_in_group > cache->key.offset);
5146
5147                 spin_lock(&cache->space_info->lock);
5148                 spin_lock(&cache->lock);
5149
5150                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5151                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5152                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5153
5154                 cache->dirty = 1;
5155                 old_val = btrfs_block_group_used(&cache->item);
5156                 num_bytes = min(total, cache->key.offset - byte_in_group);
5157                 if (alloc) {
5158                         old_val += num_bytes;
5159                         btrfs_set_block_group_used(&cache->item, old_val);
5160                         cache->reserved -= num_bytes;
5161                         cache->space_info->bytes_reserved -= num_bytes;
5162                         cache->space_info->bytes_used += num_bytes;
5163                         cache->space_info->disk_used += num_bytes * factor;
5164                         spin_unlock(&cache->lock);
5165                         spin_unlock(&cache->space_info->lock);
5166                 } else {
5167                         old_val -= num_bytes;
5168                         btrfs_set_block_group_used(&cache->item, old_val);
5169                         cache->pinned += num_bytes;
5170                         cache->space_info->bytes_pinned += num_bytes;
5171                         cache->space_info->bytes_used -= num_bytes;
5172                         cache->space_info->disk_used -= num_bytes * factor;
5173                         spin_unlock(&cache->lock);
5174                         spin_unlock(&cache->space_info->lock);
5175
5176                         set_extent_dirty(info->pinned_extents,
5177                                          bytenr, bytenr + num_bytes - 1,
5178                                          GFP_NOFS | __GFP_NOFAIL);
5179                 }
5180                 btrfs_put_block_group(cache);
5181                 total -= num_bytes;
5182                 bytenr += num_bytes;
5183         }
5184         return 0;
5185 }
5186
5187 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5188 {
5189         struct btrfs_block_group_cache *cache;
5190         u64 bytenr;
5191
5192         spin_lock(&root->fs_info->block_group_cache_lock);
5193         bytenr = root->fs_info->first_logical_byte;
5194         spin_unlock(&root->fs_info->block_group_cache_lock);
5195
5196         if (bytenr < (u64)-1)
5197                 return bytenr;
5198
5199         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5200         if (!cache)
5201                 return 0;
5202
5203         bytenr = cache->key.objectid;
5204         btrfs_put_block_group(cache);
5205
5206         return bytenr;
5207 }
5208
5209 static int pin_down_extent(struct btrfs_root *root,
5210                            struct btrfs_block_group_cache *cache,
5211                            u64 bytenr, u64 num_bytes, int reserved)
5212 {
5213         spin_lock(&cache->space_info->lock);
5214         spin_lock(&cache->lock);
5215         cache->pinned += num_bytes;
5216         cache->space_info->bytes_pinned += num_bytes;
5217         if (reserved) {
5218                 cache->reserved -= num_bytes;
5219                 cache->space_info->bytes_reserved -= num_bytes;
5220         }
5221         spin_unlock(&cache->lock);
5222         spin_unlock(&cache->space_info->lock);
5223
5224         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5225                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5226         return 0;
5227 }
5228
5229 /*
5230  * this function must be called within transaction
5231  */
5232 int btrfs_pin_extent(struct btrfs_root *root,
5233                      u64 bytenr, u64 num_bytes, int reserved)
5234 {
5235         struct btrfs_block_group_cache *cache;
5236
5237         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5238         BUG_ON(!cache); /* Logic error */
5239
5240         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5241
5242         btrfs_put_block_group(cache);
5243         return 0;
5244 }
5245
5246 /*
5247  * this function must be called within transaction
5248  */
5249 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5250                                     u64 bytenr, u64 num_bytes)
5251 {
5252         struct btrfs_block_group_cache *cache;
5253         int ret;
5254
5255         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5256         if (!cache)
5257                 return -EINVAL;
5258
5259         /*
5260          * pull in the free space cache (if any) so that our pin
5261          * removes the free space from the cache.  We have load_only set
5262          * to one because the slow code to read in the free extents does check
5263          * the pinned extents.
5264          */
5265         cache_block_group(cache, 1);
5266
5267         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5268
5269         /* remove us from the free space cache (if we're there at all) */
5270         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5271         btrfs_put_block_group(cache);
5272         return ret;
5273 }
5274
5275 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5276 {
5277         int ret;
5278         struct btrfs_block_group_cache *block_group;
5279         struct btrfs_caching_control *caching_ctl;
5280
5281         block_group = btrfs_lookup_block_group(root->fs_info, start);
5282         if (!block_group)
5283                 return -EINVAL;
5284
5285         cache_block_group(block_group, 0);
5286         caching_ctl = get_caching_control(block_group);
5287
5288         if (!caching_ctl) {
5289                 /* Logic error */
5290                 BUG_ON(!block_group_cache_done(block_group));
5291                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5292         } else {
5293                 mutex_lock(&caching_ctl->mutex);
5294
5295                 if (start >= caching_ctl->progress) {
5296                         ret = add_excluded_extent(root, start, num_bytes);
5297                 } else if (start + num_bytes <= caching_ctl->progress) {
5298                         ret = btrfs_remove_free_space(block_group,
5299                                                       start, num_bytes);
5300                 } else {
5301                         num_bytes = caching_ctl->progress - start;
5302                         ret = btrfs_remove_free_space(block_group,
5303                                                       start, num_bytes);
5304                         if (ret)
5305                                 goto out_lock;
5306
5307                         num_bytes = (start + num_bytes) -
5308                                 caching_ctl->progress;
5309                         start = caching_ctl->progress;
5310                         ret = add_excluded_extent(root, start, num_bytes);
5311                 }
5312 out_lock:
5313                 mutex_unlock(&caching_ctl->mutex);
5314                 put_caching_control(caching_ctl);
5315         }
5316         btrfs_put_block_group(block_group);
5317         return ret;
5318 }
5319
5320 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5321                                  struct extent_buffer *eb)
5322 {
5323         struct btrfs_file_extent_item *item;
5324         struct btrfs_key key;
5325         int found_type;
5326         int i;
5327
5328         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5329                 return 0;
5330
5331         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5332                 btrfs_item_key_to_cpu(eb, &key, i);
5333                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5334                         continue;
5335                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5336                 found_type = btrfs_file_extent_type(eb, item);
5337                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5338                         continue;
5339                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5340                         continue;
5341                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5342                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5343                 __exclude_logged_extent(log, key.objectid, key.offset);
5344         }
5345
5346         return 0;
5347 }
5348
5349 /**
5350  * btrfs_update_reserved_bytes - update the block_group and space info counters
5351  * @cache:      The cache we are manipulating
5352  * @num_bytes:  The number of bytes in question
5353  * @reserve:    One of the reservation enums
5354  *
5355  * This is called by the allocator when it reserves space, or by somebody who is
5356  * freeing space that was never actually used on disk.  For example if you
5357  * reserve some space for a new leaf in transaction A and before transaction A
5358  * commits you free that leaf, you call this with reserve set to 0 in order to
5359  * clear the reservation.
5360  *
5361  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5362  * ENOSPC accounting.  For data we handle the reservation through clearing the
5363  * delalloc bits in the io_tree.  We have to do this since we could end up
5364  * allocating less disk space for the amount of data we have reserved in the
5365  * case of compression.
5366  *
5367  * If this is a reservation and the block group has become read only we cannot
5368  * make the reservation and return -EAGAIN, otherwise this function always
5369  * succeeds.
5370  */
5371 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5372                                        u64 num_bytes, int reserve)
5373 {
5374         struct btrfs_space_info *space_info = cache->space_info;
5375         int ret = 0;
5376
5377         spin_lock(&space_info->lock);
5378         spin_lock(&cache->lock);
5379         if (reserve != RESERVE_FREE) {
5380                 if (cache->ro) {
5381                         ret = -EAGAIN;
5382                 } else {
5383                         cache->reserved += num_bytes;
5384                         space_info->bytes_reserved += num_bytes;
5385                         if (reserve == RESERVE_ALLOC) {
5386                                 trace_btrfs_space_reservation(cache->fs_info,
5387                                                 "space_info", space_info->flags,
5388                                                 num_bytes, 0);
5389                                 space_info->bytes_may_use -= num_bytes;
5390                         }
5391                 }
5392         } else {
5393                 if (cache->ro)
5394                         space_info->bytes_readonly += num_bytes;
5395                 cache->reserved -= num_bytes;
5396                 space_info->bytes_reserved -= num_bytes;
5397                 space_info->reservation_progress++;
5398         }
5399         spin_unlock(&cache->lock);
5400         spin_unlock(&space_info->lock);
5401         return ret;
5402 }
5403
5404 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5405                                 struct btrfs_root *root)
5406 {
5407         struct btrfs_fs_info *fs_info = root->fs_info;
5408         struct btrfs_caching_control *next;
5409         struct btrfs_caching_control *caching_ctl;
5410         struct btrfs_block_group_cache *cache;
5411         struct btrfs_space_info *space_info;
5412
5413         down_write(&fs_info->extent_commit_sem);
5414
5415         list_for_each_entry_safe(caching_ctl, next,
5416                                  &fs_info->caching_block_groups, list) {
5417                 cache = caching_ctl->block_group;
5418                 if (block_group_cache_done(cache)) {
5419                         cache->last_byte_to_unpin = (u64)-1;
5420                         list_del_init(&caching_ctl->list);
5421                         put_caching_control(caching_ctl);
5422                 } else {
5423                         cache->last_byte_to_unpin = caching_ctl->progress;
5424                 }
5425         }
5426
5427         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5428                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5429         else
5430                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5431
5432         up_write(&fs_info->extent_commit_sem);
5433
5434         list_for_each_entry_rcu(space_info, &fs_info->space_info, list)
5435                 percpu_counter_set(&space_info->total_bytes_pinned, 0);
5436
5437         update_global_block_rsv(fs_info);
5438 }
5439
5440 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5441 {
5442         struct btrfs_fs_info *fs_info = root->fs_info;
5443         struct btrfs_block_group_cache *cache = NULL;
5444         struct btrfs_space_info *space_info;
5445         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5446         u64 len;
5447         bool readonly;
5448
5449         while (start <= end) {
5450                 readonly = false;
5451                 if (!cache ||
5452                     start >= cache->key.objectid + cache->key.offset) {
5453                         if (cache)
5454                                 btrfs_put_block_group(cache);
5455                         cache = btrfs_lookup_block_group(fs_info, start);
5456                         BUG_ON(!cache); /* Logic error */
5457                 }
5458
5459                 len = cache->key.objectid + cache->key.offset - start;
5460                 len = min(len, end + 1 - start);
5461
5462                 if (start < cache->last_byte_to_unpin) {
5463                         len = min(len, cache->last_byte_to_unpin - start);
5464                         btrfs_add_free_space(cache, start, len);
5465                 }
5466
5467                 start += len;
5468                 space_info = cache->space_info;
5469
5470                 spin_lock(&space_info->lock);
5471                 spin_lock(&cache->lock);
5472                 cache->pinned -= len;
5473                 space_info->bytes_pinned -= len;
5474                 if (cache->ro) {
5475                         space_info->bytes_readonly += len;
5476                         readonly = true;
5477                 }
5478                 spin_unlock(&cache->lock);
5479                 if (!readonly && global_rsv->space_info == space_info) {
5480                         spin_lock(&global_rsv->lock);
5481                         if (!global_rsv->full) {
5482                                 len = min(len, global_rsv->size -
5483                                           global_rsv->reserved);
5484                                 global_rsv->reserved += len;
5485                                 space_info->bytes_may_use += len;
5486                                 if (global_rsv->reserved >= global_rsv->size)
5487                                         global_rsv->full = 1;
5488                         }
5489                         spin_unlock(&global_rsv->lock);
5490                 }
5491                 spin_unlock(&space_info->lock);
5492         }
5493
5494         if (cache)
5495                 btrfs_put_block_group(cache);
5496         return 0;
5497 }
5498
5499 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5500                                struct btrfs_root *root)
5501 {
5502         struct btrfs_fs_info *fs_info = root->fs_info;
5503         struct extent_io_tree *unpin;
5504         u64 start;
5505         u64 end;
5506         int ret;
5507
5508         if (trans->aborted)
5509                 return 0;
5510
5511         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5512                 unpin = &fs_info->freed_extents[1];
5513         else
5514                 unpin = &fs_info->freed_extents[0];
5515
5516         while (1) {
5517                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5518                                             EXTENT_DIRTY, NULL);
5519                 if (ret)
5520                         break;
5521
5522                 if (btrfs_test_opt(root, DISCARD))
5523                         ret = btrfs_discard_extent(root, start,
5524                                                    end + 1 - start, NULL);
5525
5526                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5527                 unpin_extent_range(root, start, end);
5528                 cond_resched();
5529         }
5530
5531         return 0;
5532 }
5533
5534 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
5535                              u64 owner, u64 root_objectid)
5536 {
5537         struct btrfs_space_info *space_info;
5538         u64 flags;
5539
5540         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5541                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
5542                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
5543                 else
5544                         flags = BTRFS_BLOCK_GROUP_METADATA;
5545         } else {
5546                 flags = BTRFS_BLOCK_GROUP_DATA;
5547         }
5548
5549         space_info = __find_space_info(fs_info, flags);
5550         BUG_ON(!space_info); /* Logic bug */
5551         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
5552 }
5553
5554
5555 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5556                                 struct btrfs_root *root,
5557                                 u64 bytenr, u64 num_bytes, u64 parent,
5558                                 u64 root_objectid, u64 owner_objectid,
5559                                 u64 owner_offset, int refs_to_drop,
5560                                 struct btrfs_delayed_extent_op *extent_op)
5561 {
5562         struct btrfs_key key;
5563         struct btrfs_path *path;
5564         struct btrfs_fs_info *info = root->fs_info;
5565         struct btrfs_root *extent_root = info->extent_root;
5566         struct extent_buffer *leaf;
5567         struct btrfs_extent_item *ei;
5568         struct btrfs_extent_inline_ref *iref;
5569         int ret;
5570         int is_data;
5571         int extent_slot = 0;
5572         int found_extent = 0;
5573         int num_to_del = 1;
5574         u32 item_size;
5575         u64 refs;
5576         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5577                                                  SKINNY_METADATA);
5578
5579         path = btrfs_alloc_path();
5580         if (!path)
5581                 return -ENOMEM;
5582
5583         path->reada = 1;
5584         path->leave_spinning = 1;
5585
5586         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5587         BUG_ON(!is_data && refs_to_drop != 1);
5588
5589         if (is_data)
5590                 skinny_metadata = 0;
5591
5592         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5593                                     bytenr, num_bytes, parent,
5594                                     root_objectid, owner_objectid,
5595                                     owner_offset);
5596         if (ret == 0) {
5597                 extent_slot = path->slots[0];
5598                 while (extent_slot >= 0) {
5599                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5600                                               extent_slot);
5601                         if (key.objectid != bytenr)
5602                                 break;
5603                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5604                             key.offset == num_bytes) {
5605                                 found_extent = 1;
5606                                 break;
5607                         }
5608                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5609                             key.offset == owner_objectid) {
5610                                 found_extent = 1;
5611                                 break;
5612                         }
5613                         if (path->slots[0] - extent_slot > 5)
5614                                 break;
5615                         extent_slot--;
5616                 }
5617 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5618                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5619                 if (found_extent && item_size < sizeof(*ei))
5620                         found_extent = 0;
5621 #endif
5622                 if (!found_extent) {
5623                         BUG_ON(iref);
5624                         ret = remove_extent_backref(trans, extent_root, path,
5625                                                     NULL, refs_to_drop,
5626                                                     is_data);
5627                         if (ret) {
5628                                 btrfs_abort_transaction(trans, extent_root, ret);
5629                                 goto out;
5630                         }
5631                         btrfs_release_path(path);
5632                         path->leave_spinning = 1;
5633
5634                         key.objectid = bytenr;
5635                         key.type = BTRFS_EXTENT_ITEM_KEY;
5636                         key.offset = num_bytes;
5637
5638                         if (!is_data && skinny_metadata) {
5639                                 key.type = BTRFS_METADATA_ITEM_KEY;
5640                                 key.offset = owner_objectid;
5641                         }
5642
5643                         ret = btrfs_search_slot(trans, extent_root,
5644                                                 &key, path, -1, 1);
5645                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5646                                 /*
5647                                  * Couldn't find our skinny metadata item,
5648                                  * see if we have ye olde extent item.
5649                                  */
5650                                 path->slots[0]--;
5651                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5652                                                       path->slots[0]);
5653                                 if (key.objectid == bytenr &&
5654                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5655                                     key.offset == num_bytes)
5656                                         ret = 0;
5657                         }
5658
5659                         if (ret > 0 && skinny_metadata) {
5660                                 skinny_metadata = false;
5661                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5662                                 key.offset = num_bytes;
5663                                 btrfs_release_path(path);
5664                                 ret = btrfs_search_slot(trans, extent_root,
5665                                                         &key, path, -1, 1);
5666                         }
5667
5668                         if (ret) {
5669                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5670                                         ret, (unsigned long long)bytenr);
5671                                 if (ret > 0)
5672                                         btrfs_print_leaf(extent_root,
5673                                                          path->nodes[0]);
5674                         }
5675                         if (ret < 0) {
5676                                 btrfs_abort_transaction(trans, extent_root, ret);
5677                                 goto out;
5678                         }
5679                         extent_slot = path->slots[0];
5680                 }
5681         } else if (ret == -ENOENT) {
5682                 btrfs_print_leaf(extent_root, path->nodes[0]);
5683                 WARN_ON(1);
5684                 btrfs_err(info,
5685                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5686                         (unsigned long long)bytenr,
5687                         (unsigned long long)parent,
5688                         (unsigned long long)root_objectid,
5689                         (unsigned long long)owner_objectid,
5690                         (unsigned long long)owner_offset);
5691         } else {
5692                 btrfs_abort_transaction(trans, extent_root, ret);
5693                 goto out;
5694         }
5695
5696         leaf = path->nodes[0];
5697         item_size = btrfs_item_size_nr(leaf, extent_slot);
5698 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5699         if (item_size < sizeof(*ei)) {
5700                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5701                 ret = convert_extent_item_v0(trans, extent_root, path,
5702                                              owner_objectid, 0);
5703                 if (ret < 0) {
5704                         btrfs_abort_transaction(trans, extent_root, ret);
5705                         goto out;
5706                 }
5707
5708                 btrfs_release_path(path);
5709                 path->leave_spinning = 1;
5710
5711                 key.objectid = bytenr;
5712                 key.type = BTRFS_EXTENT_ITEM_KEY;
5713                 key.offset = num_bytes;
5714
5715                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5716                                         -1, 1);
5717                 if (ret) {
5718                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5719                                 ret, (unsigned long long)bytenr);
5720                         btrfs_print_leaf(extent_root, path->nodes[0]);
5721                 }
5722                 if (ret < 0) {
5723                         btrfs_abort_transaction(trans, extent_root, ret);
5724                         goto out;
5725                 }
5726
5727                 extent_slot = path->slots[0];
5728                 leaf = path->nodes[0];
5729                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5730         }
5731 #endif
5732         BUG_ON(item_size < sizeof(*ei));
5733         ei = btrfs_item_ptr(leaf, extent_slot,
5734                             struct btrfs_extent_item);
5735         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
5736             key.type == BTRFS_EXTENT_ITEM_KEY) {
5737                 struct btrfs_tree_block_info *bi;
5738                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5739                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5740                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5741         }
5742
5743         refs = btrfs_extent_refs(leaf, ei);
5744         if (refs < refs_to_drop) {
5745                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
5746                           "for bytenr %Lu\n", refs_to_drop, refs, bytenr);
5747                 ret = -EINVAL;
5748                 btrfs_abort_transaction(trans, extent_root, ret);
5749                 goto out;
5750         }
5751         refs -= refs_to_drop;
5752
5753         if (refs > 0) {
5754                 if (extent_op)
5755                         __run_delayed_extent_op(extent_op, leaf, ei);
5756                 /*
5757                  * In the case of inline back ref, reference count will
5758                  * be updated by remove_extent_backref
5759                  */
5760                 if (iref) {
5761                         BUG_ON(!found_extent);
5762                 } else {
5763                         btrfs_set_extent_refs(leaf, ei, refs);
5764                         btrfs_mark_buffer_dirty(leaf);
5765                 }
5766                 if (found_extent) {
5767                         ret = remove_extent_backref(trans, extent_root, path,
5768                                                     iref, refs_to_drop,
5769                                                     is_data);
5770                         if (ret) {
5771                                 btrfs_abort_transaction(trans, extent_root, ret);
5772                                 goto out;
5773                         }
5774                 }
5775                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
5776                                  root_objectid);
5777         } else {
5778                 if (found_extent) {
5779                         BUG_ON(is_data && refs_to_drop !=
5780                                extent_data_ref_count(root, path, iref));
5781                         if (iref) {
5782                                 BUG_ON(path->slots[0] != extent_slot);
5783                         } else {
5784                                 BUG_ON(path->slots[0] != extent_slot + 1);
5785                                 path->slots[0] = extent_slot;
5786                                 num_to_del = 2;
5787                         }
5788                 }
5789
5790                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5791                                       num_to_del);
5792                 if (ret) {
5793                         btrfs_abort_transaction(trans, extent_root, ret);
5794                         goto out;
5795                 }
5796                 btrfs_release_path(path);
5797
5798                 if (is_data) {
5799                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5800                         if (ret) {
5801                                 btrfs_abort_transaction(trans, extent_root, ret);
5802                                 goto out;
5803                         }
5804                 }
5805
5806                 ret = update_block_group(root, bytenr, num_bytes, 0);
5807                 if (ret) {
5808                         btrfs_abort_transaction(trans, extent_root, ret);
5809                         goto out;
5810                 }
5811         }
5812 out:
5813         btrfs_free_path(path);
5814         return ret;
5815 }
5816
5817 /*
5818  * when we free an block, it is possible (and likely) that we free the last
5819  * delayed ref for that extent as well.  This searches the delayed ref tree for
5820  * a given extent, and if there are no other delayed refs to be processed, it
5821  * removes it from the tree.
5822  */
5823 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5824                                       struct btrfs_root *root, u64 bytenr)
5825 {
5826         struct btrfs_delayed_ref_head *head;
5827         struct btrfs_delayed_ref_root *delayed_refs;
5828         struct btrfs_delayed_ref_node *ref;
5829         struct rb_node *node;
5830         int ret = 0;
5831
5832         delayed_refs = &trans->transaction->delayed_refs;
5833         spin_lock(&delayed_refs->lock);
5834         head = btrfs_find_delayed_ref_head(trans, bytenr);
5835         if (!head)
5836                 goto out;
5837
5838         node = rb_prev(&head->node.rb_node);
5839         if (!node)
5840                 goto out;
5841
5842         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5843
5844         /* there are still entries for this ref, we can't drop it */
5845         if (ref->bytenr == bytenr)
5846                 goto out;
5847
5848         if (head->extent_op) {
5849                 if (!head->must_insert_reserved)
5850                         goto out;
5851                 btrfs_free_delayed_extent_op(head->extent_op);
5852                 head->extent_op = NULL;
5853         }
5854
5855         /*
5856          * waiting for the lock here would deadlock.  If someone else has it
5857          * locked they are already in the process of dropping it anyway
5858          */
5859         if (!mutex_trylock(&head->mutex))
5860                 goto out;
5861
5862         /*
5863          * at this point we have a head with no other entries.  Go
5864          * ahead and process it.
5865          */
5866         head->node.in_tree = 0;
5867         rb_erase(&head->node.rb_node, &delayed_refs->root);
5868
5869         delayed_refs->num_entries--;
5870
5871         /*
5872          * we don't take a ref on the node because we're removing it from the
5873          * tree, so we just steal the ref the tree was holding.
5874          */
5875         delayed_refs->num_heads--;
5876         if (list_empty(&head->cluster))
5877                 delayed_refs->num_heads_ready--;
5878
5879         list_del_init(&head->cluster);
5880         spin_unlock(&delayed_refs->lock);
5881
5882         BUG_ON(head->extent_op);
5883         if (head->must_insert_reserved)
5884                 ret = 1;
5885
5886         mutex_unlock(&head->mutex);
5887         btrfs_put_delayed_ref(&head->node);
5888         return ret;
5889 out:
5890         spin_unlock(&delayed_refs->lock);
5891         return 0;
5892 }
5893
5894 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5895                            struct btrfs_root *root,
5896                            struct extent_buffer *buf,
5897                            u64 parent, int last_ref)
5898 {
5899         struct btrfs_block_group_cache *cache = NULL;
5900         int pin = 1;
5901         int ret;
5902
5903         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5904                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5905                                         buf->start, buf->len,
5906                                         parent, root->root_key.objectid,
5907                                         btrfs_header_level(buf),
5908                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5909                 BUG_ON(ret); /* -ENOMEM */
5910         }
5911
5912         if (!last_ref)
5913                 return;
5914
5915         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5916
5917         if (btrfs_header_generation(buf) == trans->transid) {
5918                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5919                         ret = check_ref_cleanup(trans, root, buf->start);
5920                         if (!ret)
5921                                 goto out;
5922                 }
5923
5924                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5925                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5926                         goto out;
5927                 }
5928
5929                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5930
5931                 btrfs_add_free_space(cache, buf->start, buf->len);
5932                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5933                 pin = 0;
5934         }
5935 out:
5936         if (pin)
5937                 add_pinned_bytes(root->fs_info, buf->len,
5938                                  btrfs_header_level(buf),
5939                                  root->root_key.objectid);
5940
5941         /*
5942          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5943          * anymore.
5944          */
5945         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5946         btrfs_put_block_group(cache);
5947 }
5948
5949 /* Can return -ENOMEM */
5950 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5951                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5952                       u64 owner, u64 offset, int for_cow)
5953 {
5954         int ret;
5955         struct btrfs_fs_info *fs_info = root->fs_info;
5956
5957         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
5958
5959         /*
5960          * tree log blocks never actually go into the extent allocation
5961          * tree, just update pinning info and exit early.
5962          */
5963         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5964                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5965                 /* unlocks the pinned mutex */
5966                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5967                 ret = 0;
5968         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5969                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5970                                         num_bytes,
5971                                         parent, root_objectid, (int)owner,
5972                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5973         } else {
5974                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5975                                                 num_bytes,
5976                                                 parent, root_objectid, owner,
5977                                                 offset, BTRFS_DROP_DELAYED_REF,
5978                                                 NULL, for_cow);
5979         }
5980         return ret;
5981 }
5982
5983 static u64 stripe_align(struct btrfs_root *root,
5984                         struct btrfs_block_group_cache *cache,
5985                         u64 val, u64 num_bytes)
5986 {
5987         u64 ret = ALIGN(val, root->stripesize);
5988         return ret;
5989 }
5990
5991 /*
5992  * when we wait for progress in the block group caching, its because
5993  * our allocation attempt failed at least once.  So, we must sleep
5994  * and let some progress happen before we try again.
5995  *
5996  * This function will sleep at least once waiting for new free space to
5997  * show up, and then it will check the block group free space numbers
5998  * for our min num_bytes.  Another option is to have it go ahead
5999  * and look in the rbtree for a free extent of a given size, but this
6000  * is a good start.
6001  */
6002 static noinline int
6003 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6004                                 u64 num_bytes)
6005 {
6006         struct btrfs_caching_control *caching_ctl;
6007
6008         caching_ctl = get_caching_control(cache);
6009         if (!caching_ctl)
6010                 return 0;
6011
6012         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6013                    (cache->free_space_ctl->free_space >= num_bytes));
6014
6015         put_caching_control(caching_ctl);
6016         return 0;
6017 }
6018
6019 static noinline int
6020 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6021 {
6022         struct btrfs_caching_control *caching_ctl;
6023
6024         caching_ctl = get_caching_control(cache);
6025         if (!caching_ctl)
6026                 return 0;
6027
6028         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6029
6030         put_caching_control(caching_ctl);
6031         return 0;
6032 }
6033
6034 int __get_raid_index(u64 flags)
6035 {
6036         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6037                 return BTRFS_RAID_RAID10;
6038         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6039                 return BTRFS_RAID_RAID1;
6040         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6041                 return BTRFS_RAID_DUP;
6042         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6043                 return BTRFS_RAID_RAID0;
6044         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6045                 return BTRFS_RAID_RAID5;
6046         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6047                 return BTRFS_RAID_RAID6;
6048
6049         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6050 }
6051
6052 static int get_block_group_index(struct btrfs_block_group_cache *cache)
6053 {
6054         return __get_raid_index(cache->flags);
6055 }
6056
6057 enum btrfs_loop_type {
6058         LOOP_CACHING_NOWAIT = 0,
6059         LOOP_CACHING_WAIT = 1,
6060         LOOP_ALLOC_CHUNK = 2,
6061         LOOP_NO_EMPTY_SIZE = 3,
6062 };
6063
6064 /*
6065  * walks the btree of allocated extents and find a hole of a given size.
6066  * The key ins is changed to record the hole:
6067  * ins->objectid == block start
6068  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6069  * ins->offset == number of blocks
6070  * Any available blocks before search_start are skipped.
6071  */
6072 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
6073                                      struct btrfs_root *orig_root,
6074                                      u64 num_bytes, u64 empty_size,
6075                                      u64 hint_byte, struct btrfs_key *ins,
6076                                      u64 flags)
6077 {
6078         int ret = 0;
6079         struct btrfs_root *root = orig_root->fs_info->extent_root;
6080         struct btrfs_free_cluster *last_ptr = NULL;
6081         struct btrfs_block_group_cache *block_group = NULL;
6082         struct btrfs_block_group_cache *used_block_group;
6083         u64 search_start = 0;
6084         int empty_cluster = 2 * 1024 * 1024;
6085         struct btrfs_space_info *space_info;
6086         int loop = 0;
6087         int index = __get_raid_index(flags);
6088         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6089                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6090         bool found_uncached_bg = false;
6091         bool failed_cluster_refill = false;
6092         bool failed_alloc = false;
6093         bool use_cluster = true;
6094         bool have_caching_bg = false;
6095
6096         WARN_ON(num_bytes < root->sectorsize);
6097         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
6098         ins->objectid = 0;
6099         ins->offset = 0;
6100
6101         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6102
6103         space_info = __find_space_info(root->fs_info, flags);
6104         if (!space_info) {
6105                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6106                 return -ENOSPC;
6107         }
6108
6109         /*
6110          * If the space info is for both data and metadata it means we have a
6111          * small filesystem and we can't use the clustering stuff.
6112          */
6113         if (btrfs_mixed_space_info(space_info))
6114                 use_cluster = false;
6115
6116         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6117                 last_ptr = &root->fs_info->meta_alloc_cluster;
6118                 if (!btrfs_test_opt(root, SSD))
6119                         empty_cluster = 64 * 1024;
6120         }
6121
6122         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6123             btrfs_test_opt(root, SSD)) {
6124                 last_ptr = &root->fs_info->data_alloc_cluster;
6125         }
6126
6127         if (last_ptr) {
6128                 spin_lock(&last_ptr->lock);
6129                 if (last_ptr->block_group)
6130                         hint_byte = last_ptr->window_start;
6131                 spin_unlock(&last_ptr->lock);
6132         }
6133
6134         search_start = max(search_start, first_logical_byte(root, 0));
6135         search_start = max(search_start, hint_byte);
6136
6137         if (!last_ptr)
6138                 empty_cluster = 0;
6139
6140         if (search_start == hint_byte) {
6141                 block_group = btrfs_lookup_block_group(root->fs_info,
6142                                                        search_start);
6143                 used_block_group = block_group;
6144                 /*
6145                  * we don't want to use the block group if it doesn't match our
6146                  * allocation bits, or if its not cached.
6147                  *
6148                  * However if we are re-searching with an ideal block group
6149                  * picked out then we don't care that the block group is cached.
6150                  */
6151                 if (block_group && block_group_bits(block_group, flags) &&
6152                     block_group->cached != BTRFS_CACHE_NO) {
6153                         down_read(&space_info->groups_sem);
6154                         if (list_empty(&block_group->list) ||
6155                             block_group->ro) {
6156                                 /*
6157                                  * someone is removing this block group,
6158                                  * we can't jump into the have_block_group
6159                                  * target because our list pointers are not
6160                                  * valid
6161                                  */
6162                                 btrfs_put_block_group(block_group);
6163                                 up_read(&space_info->groups_sem);
6164                         } else {
6165                                 index = get_block_group_index(block_group);
6166                                 goto have_block_group;
6167                         }
6168                 } else if (block_group) {
6169                         btrfs_put_block_group(block_group);
6170                 }
6171         }
6172 search:
6173         have_caching_bg = false;
6174         down_read(&space_info->groups_sem);
6175         list_for_each_entry(block_group, &space_info->block_groups[index],
6176                             list) {
6177                 u64 offset;
6178                 int cached;
6179
6180                 used_block_group = block_group;
6181                 btrfs_get_block_group(block_group);
6182                 search_start = block_group->key.objectid;
6183
6184                 /*
6185                  * this can happen if we end up cycling through all the
6186                  * raid types, but we want to make sure we only allocate
6187                  * for the proper type.
6188                  */
6189                 if (!block_group_bits(block_group, flags)) {
6190                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6191                                 BTRFS_BLOCK_GROUP_RAID1 |
6192                                 BTRFS_BLOCK_GROUP_RAID5 |
6193                                 BTRFS_BLOCK_GROUP_RAID6 |
6194                                 BTRFS_BLOCK_GROUP_RAID10;
6195
6196                         /*
6197                          * if they asked for extra copies and this block group
6198                          * doesn't provide them, bail.  This does allow us to
6199                          * fill raid0 from raid1.
6200                          */
6201                         if ((flags & extra) && !(block_group->flags & extra))
6202                                 goto loop;
6203                 }
6204
6205 have_block_group:
6206                 cached = block_group_cache_done(block_group);
6207                 if (unlikely(!cached)) {
6208                         found_uncached_bg = true;
6209                         ret = cache_block_group(block_group, 0);
6210                         BUG_ON(ret < 0);
6211                         ret = 0;
6212                 }
6213
6214                 if (unlikely(block_group->ro))
6215                         goto loop;
6216
6217                 /*
6218                  * Ok we want to try and use the cluster allocator, so
6219                  * lets look there
6220                  */
6221                 if (last_ptr) {
6222                         unsigned long aligned_cluster;
6223                         /*
6224                          * the refill lock keeps out other
6225                          * people trying to start a new cluster
6226                          */
6227                         spin_lock(&last_ptr->refill_lock);
6228                         used_block_group = last_ptr->block_group;
6229                         if (used_block_group != block_group &&
6230                             (!used_block_group ||
6231                              used_block_group->ro ||
6232                              !block_group_bits(used_block_group, flags))) {
6233                                 used_block_group = block_group;
6234                                 goto refill_cluster;
6235                         }
6236
6237                         if (used_block_group != block_group)
6238                                 btrfs_get_block_group(used_block_group);
6239
6240                         offset = btrfs_alloc_from_cluster(used_block_group,
6241                           last_ptr, num_bytes, used_block_group->key.objectid);
6242                         if (offset) {
6243                                 /* we have a block, we're done */
6244                                 spin_unlock(&last_ptr->refill_lock);
6245                                 trace_btrfs_reserve_extent_cluster(root,
6246                                         block_group, search_start, num_bytes);
6247                                 goto checks;
6248                         }
6249
6250                         WARN_ON(last_ptr->block_group != used_block_group);
6251                         if (used_block_group != block_group) {
6252                                 btrfs_put_block_group(used_block_group);
6253                                 used_block_group = block_group;
6254                         }
6255 refill_cluster:
6256                         BUG_ON(used_block_group != block_group);
6257                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6258                          * set up a new clusters, so lets just skip it
6259                          * and let the allocator find whatever block
6260                          * it can find.  If we reach this point, we
6261                          * will have tried the cluster allocator
6262                          * plenty of times and not have found
6263                          * anything, so we are likely way too
6264                          * fragmented for the clustering stuff to find
6265                          * anything.
6266                          *
6267                          * However, if the cluster is taken from the
6268                          * current block group, release the cluster
6269                          * first, so that we stand a better chance of
6270                          * succeeding in the unclustered
6271                          * allocation.  */
6272                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6273                             last_ptr->block_group != block_group) {
6274                                 spin_unlock(&last_ptr->refill_lock);
6275                                 goto unclustered_alloc;
6276                         }
6277
6278                         /*
6279                          * this cluster didn't work out, free it and
6280                          * start over
6281                          */
6282                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6283
6284                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6285                                 spin_unlock(&last_ptr->refill_lock);
6286                                 goto unclustered_alloc;
6287                         }
6288
6289                         aligned_cluster = max_t(unsigned long,
6290                                                 empty_cluster + empty_size,
6291                                               block_group->full_stripe_len);
6292
6293                         /* allocate a cluster in this block group */
6294                         ret = btrfs_find_space_cluster(trans, root,
6295                                                block_group, last_ptr,
6296                                                search_start, num_bytes,
6297                                                aligned_cluster);
6298                         if (ret == 0) {
6299                                 /*
6300                                  * now pull our allocation out of this
6301                                  * cluster
6302                                  */
6303                                 offset = btrfs_alloc_from_cluster(block_group,
6304                                                   last_ptr, num_bytes,
6305                                                   search_start);
6306                                 if (offset) {
6307                                         /* we found one, proceed */
6308                                         spin_unlock(&last_ptr->refill_lock);
6309                                         trace_btrfs_reserve_extent_cluster(root,
6310                                                 block_group, search_start,
6311                                                 num_bytes);
6312                                         goto checks;
6313                                 }
6314                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6315                                    && !failed_cluster_refill) {
6316                                 spin_unlock(&last_ptr->refill_lock);
6317
6318                                 failed_cluster_refill = true;
6319                                 wait_block_group_cache_progress(block_group,
6320                                        num_bytes + empty_cluster + empty_size);
6321                                 goto have_block_group;
6322                         }
6323
6324                         /*
6325                          * at this point we either didn't find a cluster
6326                          * or we weren't able to allocate a block from our
6327                          * cluster.  Free the cluster we've been trying
6328                          * to use, and go to the next block group
6329                          */
6330                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6331                         spin_unlock(&last_ptr->refill_lock);
6332                         goto loop;
6333                 }
6334
6335 unclustered_alloc:
6336                 spin_lock(&block_group->free_space_ctl->tree_lock);
6337                 if (cached &&
6338                     block_group->free_space_ctl->free_space <
6339                     num_bytes + empty_cluster + empty_size) {
6340                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6341                         goto loop;
6342                 }
6343                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6344
6345                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6346                                                     num_bytes, empty_size);
6347                 /*
6348                  * If we didn't find a chunk, and we haven't failed on this
6349                  * block group before, and this block group is in the middle of
6350                  * caching and we are ok with waiting, then go ahead and wait
6351                  * for progress to be made, and set failed_alloc to true.
6352                  *
6353                  * If failed_alloc is true then we've already waited on this
6354                  * block group once and should move on to the next block group.
6355                  */
6356                 if (!offset && !failed_alloc && !cached &&
6357                     loop > LOOP_CACHING_NOWAIT) {
6358                         wait_block_group_cache_progress(block_group,
6359                                                 num_bytes + empty_size);
6360                         failed_alloc = true;
6361                         goto have_block_group;
6362                 } else if (!offset) {
6363                         if (!cached)
6364                                 have_caching_bg = true;
6365                         goto loop;
6366                 }
6367 checks:
6368                 search_start = stripe_align(root, used_block_group,
6369                                             offset, num_bytes);
6370
6371                 /* move on to the next group */
6372                 if (search_start + num_bytes >
6373                     used_block_group->key.objectid + used_block_group->key.offset) {
6374                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6375                         goto loop;
6376                 }
6377
6378                 if (offset < search_start)
6379                         btrfs_add_free_space(used_block_group, offset,
6380                                              search_start - offset);
6381                 BUG_ON(offset > search_start);
6382
6383                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
6384                                                   alloc_type);
6385                 if (ret == -EAGAIN) {
6386                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6387                         goto loop;
6388                 }
6389
6390                 /* we are all good, lets return */
6391                 ins->objectid = search_start;
6392                 ins->offset = num_bytes;
6393
6394                 trace_btrfs_reserve_extent(orig_root, block_group,
6395                                            search_start, num_bytes);
6396                 if (used_block_group != block_group)
6397                         btrfs_put_block_group(used_block_group);
6398                 btrfs_put_block_group(block_group);
6399                 break;
6400 loop:
6401                 failed_cluster_refill = false;
6402                 failed_alloc = false;
6403                 BUG_ON(index != get_block_group_index(block_group));
6404                 if (used_block_group != block_group)
6405                         btrfs_put_block_group(used_block_group);
6406                 btrfs_put_block_group(block_group);
6407         }
6408         up_read(&space_info->groups_sem);
6409
6410         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6411                 goto search;
6412
6413         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6414                 goto search;
6415
6416         /*
6417          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6418          *                      caching kthreads as we move along
6419          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6420          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6421          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6422          *                      again
6423          */
6424         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6425                 index = 0;
6426                 loop++;
6427                 if (loop == LOOP_ALLOC_CHUNK) {
6428                         ret = do_chunk_alloc(trans, root, flags,
6429                                              CHUNK_ALLOC_FORCE);
6430                         /*
6431                          * Do not bail out on ENOSPC since we
6432                          * can do more things.
6433                          */
6434                         if (ret < 0 && ret != -ENOSPC) {
6435                                 btrfs_abort_transaction(trans,
6436                                                         root, ret);
6437                                 goto out;
6438                         }
6439                 }
6440
6441                 if (loop == LOOP_NO_EMPTY_SIZE) {
6442                         empty_size = 0;
6443                         empty_cluster = 0;
6444                 }
6445
6446                 goto search;
6447         } else if (!ins->objectid) {
6448                 ret = -ENOSPC;
6449         } else if (ins->objectid) {
6450                 ret = 0;
6451         }
6452 out:
6453
6454         return ret;
6455 }
6456
6457 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6458                             int dump_block_groups)
6459 {
6460         struct btrfs_block_group_cache *cache;
6461         int index = 0;
6462
6463         spin_lock(&info->lock);
6464         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
6465                (unsigned long long)info->flags,
6466                (unsigned long long)(info->total_bytes - info->bytes_used -
6467                                     info->bytes_pinned - info->bytes_reserved -
6468                                     info->bytes_readonly),
6469                (info->full) ? "" : "not ");
6470         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
6471                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6472                (unsigned long long)info->total_bytes,
6473                (unsigned long long)info->bytes_used,
6474                (unsigned long long)info->bytes_pinned,
6475                (unsigned long long)info->bytes_reserved,
6476                (unsigned long long)info->bytes_may_use,
6477                (unsigned long long)info->bytes_readonly);
6478         spin_unlock(&info->lock);
6479
6480         if (!dump_block_groups)
6481                 return;
6482
6483         down_read(&info->groups_sem);
6484 again:
6485         list_for_each_entry(cache, &info->block_groups[index], list) {
6486                 spin_lock(&cache->lock);
6487                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
6488                        (unsigned long long)cache->key.objectid,
6489                        (unsigned long long)cache->key.offset,
6490                        (unsigned long long)btrfs_block_group_used(&cache->item),
6491                        (unsigned long long)cache->pinned,
6492                        (unsigned long long)cache->reserved,
6493                        cache->ro ? "[readonly]" : "");
6494                 btrfs_dump_free_space(cache, bytes);
6495                 spin_unlock(&cache->lock);
6496         }
6497         if (++index < BTRFS_NR_RAID_TYPES)
6498                 goto again;
6499         up_read(&info->groups_sem);
6500 }
6501
6502 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
6503                          struct btrfs_root *root,
6504                          u64 num_bytes, u64 min_alloc_size,
6505                          u64 empty_size, u64 hint_byte,
6506                          struct btrfs_key *ins, int is_data)
6507 {
6508         bool final_tried = false;
6509         u64 flags;
6510         int ret;
6511
6512         flags = btrfs_get_alloc_profile(root, is_data);
6513 again:
6514         WARN_ON(num_bytes < root->sectorsize);
6515         ret = find_free_extent(trans, root, num_bytes, empty_size,
6516                                hint_byte, ins, flags);
6517
6518         if (ret == -ENOSPC) {
6519                 if (!final_tried) {
6520                         num_bytes = num_bytes >> 1;
6521                         num_bytes = round_down(num_bytes, root->sectorsize);
6522                         num_bytes = max(num_bytes, min_alloc_size);
6523                         if (num_bytes == min_alloc_size)
6524                                 final_tried = true;
6525                         goto again;
6526                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6527                         struct btrfs_space_info *sinfo;
6528
6529                         sinfo = __find_space_info(root->fs_info, flags);
6530                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6531                                 (unsigned long long)flags,
6532                                 (unsigned long long)num_bytes);
6533                         if (sinfo)
6534                                 dump_space_info(sinfo, num_bytes, 1);
6535                 }
6536         }
6537
6538         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
6539
6540         return ret;
6541 }
6542
6543 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6544                                         u64 start, u64 len, int pin)
6545 {
6546         struct btrfs_block_group_cache *cache;
6547         int ret = 0;
6548
6549         cache = btrfs_lookup_block_group(root->fs_info, start);
6550         if (!cache) {
6551                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6552                         (unsigned long long)start);
6553                 return -ENOSPC;
6554         }
6555
6556         if (btrfs_test_opt(root, DISCARD))
6557                 ret = btrfs_discard_extent(root, start, len, NULL);
6558
6559         if (pin)
6560                 pin_down_extent(root, cache, start, len, 1);
6561         else {
6562                 btrfs_add_free_space(cache, start, len);
6563                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6564         }
6565         btrfs_put_block_group(cache);
6566
6567         trace_btrfs_reserved_extent_free(root, start, len);
6568
6569         return ret;
6570 }
6571
6572 int btrfs_free_reserved_extent(struct btrfs_root *root,
6573                                         u64 start, u64 len)
6574 {
6575         return __btrfs_free_reserved_extent(root, start, len, 0);
6576 }
6577
6578 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6579                                        u64 start, u64 len)
6580 {
6581         return __btrfs_free_reserved_extent(root, start, len, 1);
6582 }
6583
6584 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6585                                       struct btrfs_root *root,
6586                                       u64 parent, u64 root_objectid,
6587                                       u64 flags, u64 owner, u64 offset,
6588                                       struct btrfs_key *ins, int ref_mod)
6589 {
6590         int ret;
6591         struct btrfs_fs_info *fs_info = root->fs_info;
6592         struct btrfs_extent_item *extent_item;
6593         struct btrfs_extent_inline_ref *iref;
6594         struct btrfs_path *path;
6595         struct extent_buffer *leaf;
6596         int type;
6597         u32 size;
6598
6599         if (parent > 0)
6600                 type = BTRFS_SHARED_DATA_REF_KEY;
6601         else
6602                 type = BTRFS_EXTENT_DATA_REF_KEY;
6603
6604         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6605
6606         path = btrfs_alloc_path();
6607         if (!path)
6608                 return -ENOMEM;
6609
6610         path->leave_spinning = 1;
6611         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6612                                       ins, size);
6613         if (ret) {
6614                 btrfs_free_path(path);
6615                 return ret;
6616         }
6617
6618         leaf = path->nodes[0];
6619         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6620                                      struct btrfs_extent_item);
6621         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6622         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6623         btrfs_set_extent_flags(leaf, extent_item,
6624                                flags | BTRFS_EXTENT_FLAG_DATA);
6625
6626         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6627         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6628         if (parent > 0) {
6629                 struct btrfs_shared_data_ref *ref;
6630                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6631                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6632                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6633         } else {
6634                 struct btrfs_extent_data_ref *ref;
6635                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6636                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6637                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6638                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6639                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6640         }
6641
6642         btrfs_mark_buffer_dirty(path->nodes[0]);
6643         btrfs_free_path(path);
6644
6645         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6646         if (ret) { /* -ENOENT, logic error */
6647                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6648                         (unsigned long long)ins->objectid,
6649                         (unsigned long long)ins->offset);
6650                 BUG();
6651         }
6652         return ret;
6653 }
6654
6655 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6656                                      struct btrfs_root *root,
6657                                      u64 parent, u64 root_objectid,
6658                                      u64 flags, struct btrfs_disk_key *key,
6659                                      int level, struct btrfs_key *ins)
6660 {
6661         int ret;
6662         struct btrfs_fs_info *fs_info = root->fs_info;
6663         struct btrfs_extent_item *extent_item;
6664         struct btrfs_tree_block_info *block_info;
6665         struct btrfs_extent_inline_ref *iref;
6666         struct btrfs_path *path;
6667         struct extent_buffer *leaf;
6668         u32 size = sizeof(*extent_item) + sizeof(*iref);
6669         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6670                                                  SKINNY_METADATA);
6671
6672         if (!skinny_metadata)
6673                 size += sizeof(*block_info);
6674
6675         path = btrfs_alloc_path();
6676         if (!path)
6677                 return -ENOMEM;
6678
6679         path->leave_spinning = 1;
6680         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6681                                       ins, size);
6682         if (ret) {
6683                 btrfs_free_path(path);
6684                 return ret;
6685         }
6686
6687         leaf = path->nodes[0];
6688         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6689                                      struct btrfs_extent_item);
6690         btrfs_set_extent_refs(leaf, extent_item, 1);
6691         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6692         btrfs_set_extent_flags(leaf, extent_item,
6693                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6694
6695         if (skinny_metadata) {
6696                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6697         } else {
6698                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6699                 btrfs_set_tree_block_key(leaf, block_info, key);
6700                 btrfs_set_tree_block_level(leaf, block_info, level);
6701                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6702         }
6703
6704         if (parent > 0) {
6705                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6706                 btrfs_set_extent_inline_ref_type(leaf, iref,
6707                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6708                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6709         } else {
6710                 btrfs_set_extent_inline_ref_type(leaf, iref,
6711                                                  BTRFS_TREE_BLOCK_REF_KEY);
6712                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6713         }
6714
6715         btrfs_mark_buffer_dirty(leaf);
6716         btrfs_free_path(path);
6717
6718         ret = update_block_group(root, ins->objectid, root->leafsize, 1);
6719         if (ret) { /* -ENOENT, logic error */
6720                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6721                         (unsigned long long)ins->objectid,
6722                         (unsigned long long)ins->offset);
6723                 BUG();
6724         }
6725         return ret;
6726 }
6727
6728 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6729                                      struct btrfs_root *root,
6730                                      u64 root_objectid, u64 owner,
6731                                      u64 offset, struct btrfs_key *ins)
6732 {
6733         int ret;
6734
6735         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6736
6737         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6738                                          ins->offset, 0,
6739                                          root_objectid, owner, offset,
6740                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6741         return ret;
6742 }
6743
6744 /*
6745  * this is used by the tree logging recovery code.  It records that
6746  * an extent has been allocated and makes sure to clear the free
6747  * space cache bits as well
6748  */
6749 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6750                                    struct btrfs_root *root,
6751                                    u64 root_objectid, u64 owner, u64 offset,
6752                                    struct btrfs_key *ins)
6753 {
6754         int ret;
6755         struct btrfs_block_group_cache *block_group;
6756
6757         /*
6758          * Mixed block groups will exclude before processing the log so we only
6759          * need to do the exlude dance if this fs isn't mixed.
6760          */
6761         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
6762                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
6763                 if (ret)
6764                         return ret;
6765         }
6766
6767         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6768         if (!block_group)
6769                 return -EINVAL;
6770
6771         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6772                                           RESERVE_ALLOC_NO_ACCOUNT);
6773         BUG_ON(ret); /* logic error */
6774         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6775                                          0, owner, offset, ins, 1);
6776         btrfs_put_block_group(block_group);
6777         return ret;
6778 }
6779
6780 static struct extent_buffer *
6781 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6782                       u64 bytenr, u32 blocksize, int level)
6783 {
6784         struct extent_buffer *buf;
6785
6786         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6787         if (!buf)
6788                 return ERR_PTR(-ENOMEM);
6789         btrfs_set_header_generation(buf, trans->transid);
6790         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6791         btrfs_tree_lock(buf);
6792         clean_tree_block(trans, root, buf);
6793         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6794
6795         btrfs_set_lock_blocking(buf);
6796         btrfs_set_buffer_uptodate(buf);
6797
6798         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6799                 /*
6800                  * we allow two log transactions at a time, use different
6801                  * EXENT bit to differentiate dirty pages.
6802                  */
6803                 if (root->log_transid % 2 == 0)
6804                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6805                                         buf->start + buf->len - 1, GFP_NOFS);
6806                 else
6807                         set_extent_new(&root->dirty_log_pages, buf->start,
6808                                         buf->start + buf->len - 1, GFP_NOFS);
6809         } else {
6810                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6811                          buf->start + buf->len - 1, GFP_NOFS);
6812         }
6813         trans->blocks_used++;
6814         /* this returns a buffer locked for blocking */
6815         return buf;
6816 }
6817
6818 static struct btrfs_block_rsv *
6819 use_block_rsv(struct btrfs_trans_handle *trans,
6820               struct btrfs_root *root, u32 blocksize)
6821 {
6822         struct btrfs_block_rsv *block_rsv;
6823         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6824         int ret;
6825         bool global_updated = false;
6826
6827         block_rsv = get_block_rsv(trans, root);
6828
6829         if (unlikely(block_rsv->size == 0))
6830                 goto try_reserve;
6831 again:
6832         ret = block_rsv_use_bytes(block_rsv, blocksize);
6833         if (!ret)
6834                 return block_rsv;
6835
6836         if (block_rsv->failfast)
6837                 return ERR_PTR(ret);
6838
6839         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
6840                 global_updated = true;
6841                 update_global_block_rsv(root->fs_info);
6842                 goto again;
6843         }
6844
6845         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6846                 static DEFINE_RATELIMIT_STATE(_rs,
6847                                 DEFAULT_RATELIMIT_INTERVAL * 10,
6848                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
6849                 if (__ratelimit(&_rs))
6850                         WARN(1, KERN_DEBUG
6851                                 "btrfs: block rsv returned %d\n", ret);
6852         }
6853 try_reserve:
6854         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
6855                                      BTRFS_RESERVE_NO_FLUSH);
6856         if (!ret)
6857                 return block_rsv;
6858         /*
6859          * If we couldn't reserve metadata bytes try and use some from
6860          * the global reserve if its space type is the same as the global
6861          * reservation.
6862          */
6863         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
6864             block_rsv->space_info == global_rsv->space_info) {
6865                 ret = block_rsv_use_bytes(global_rsv, blocksize);
6866                 if (!ret)
6867                         return global_rsv;
6868         }
6869         return ERR_PTR(ret);
6870 }
6871
6872 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6873                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6874 {
6875         block_rsv_add_bytes(block_rsv, blocksize, 0);
6876         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6877 }
6878
6879 /*
6880  * finds a free extent and does all the dirty work required for allocation
6881  * returns the key for the extent through ins, and a tree buffer for
6882  * the first block of the extent through buf.
6883  *
6884  * returns the tree buffer or NULL.
6885  */
6886 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6887                                         struct btrfs_root *root, u32 blocksize,
6888                                         u64 parent, u64 root_objectid,
6889                                         struct btrfs_disk_key *key, int level,
6890                                         u64 hint, u64 empty_size)
6891 {
6892         struct btrfs_key ins;
6893         struct btrfs_block_rsv *block_rsv;
6894         struct extent_buffer *buf;
6895         u64 flags = 0;
6896         int ret;
6897         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6898                                                  SKINNY_METADATA);
6899
6900         block_rsv = use_block_rsv(trans, root, blocksize);
6901         if (IS_ERR(block_rsv))
6902                 return ERR_CAST(block_rsv);
6903
6904         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6905                                    empty_size, hint, &ins, 0);
6906         if (ret) {
6907                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6908                 return ERR_PTR(ret);
6909         }
6910
6911         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6912                                     blocksize, level);
6913         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6914
6915         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6916                 if (parent == 0)
6917                         parent = ins.objectid;
6918                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6919         } else
6920                 BUG_ON(parent > 0);
6921
6922         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6923                 struct btrfs_delayed_extent_op *extent_op;
6924                 extent_op = btrfs_alloc_delayed_extent_op();
6925                 BUG_ON(!extent_op); /* -ENOMEM */
6926                 if (key)
6927                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6928                 else
6929                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6930                 extent_op->flags_to_set = flags;
6931                 if (skinny_metadata)
6932                         extent_op->update_key = 0;
6933                 else
6934                         extent_op->update_key = 1;
6935                 extent_op->update_flags = 1;
6936                 extent_op->is_data = 0;
6937                 extent_op->level = level;
6938
6939                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6940                                         ins.objectid,
6941                                         ins.offset, parent, root_objectid,
6942                                         level, BTRFS_ADD_DELAYED_EXTENT,
6943                                         extent_op, 0);
6944                 BUG_ON(ret); /* -ENOMEM */
6945         }
6946         return buf;
6947 }
6948
6949 struct walk_control {
6950         u64 refs[BTRFS_MAX_LEVEL];
6951         u64 flags[BTRFS_MAX_LEVEL];
6952         struct btrfs_key update_progress;
6953         int stage;
6954         int level;
6955         int shared_level;
6956         int update_ref;
6957         int keep_locks;
6958         int reada_slot;
6959         int reada_count;
6960         int for_reloc;
6961 };
6962
6963 #define DROP_REFERENCE  1
6964 #define UPDATE_BACKREF  2
6965
6966 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6967                                      struct btrfs_root *root,
6968                                      struct walk_control *wc,
6969                                      struct btrfs_path *path)
6970 {
6971         u64 bytenr;
6972         u64 generation;
6973         u64 refs;
6974         u64 flags;
6975         u32 nritems;
6976         u32 blocksize;
6977         struct btrfs_key key;
6978         struct extent_buffer *eb;
6979         int ret;
6980         int slot;
6981         int nread = 0;
6982
6983         if (path->slots[wc->level] < wc->reada_slot) {
6984                 wc->reada_count = wc->reada_count * 2 / 3;
6985                 wc->reada_count = max(wc->reada_count, 2);
6986         } else {
6987                 wc->reada_count = wc->reada_count * 3 / 2;
6988                 wc->reada_count = min_t(int, wc->reada_count,
6989                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6990         }
6991
6992         eb = path->nodes[wc->level];
6993         nritems = btrfs_header_nritems(eb);
6994         blocksize = btrfs_level_size(root, wc->level - 1);
6995
6996         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6997                 if (nread >= wc->reada_count)
6998                         break;
6999
7000                 cond_resched();
7001                 bytenr = btrfs_node_blockptr(eb, slot);
7002                 generation = btrfs_node_ptr_generation(eb, slot);
7003
7004                 if (slot == path->slots[wc->level])
7005                         goto reada;
7006
7007                 if (wc->stage == UPDATE_BACKREF &&
7008                     generation <= root->root_key.offset)
7009                         continue;
7010
7011                 /* We don't lock the tree block, it's OK to be racy here */
7012                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7013                                                wc->level - 1, 1, &refs,
7014                                                &flags);
7015                 /* We don't care about errors in readahead. */
7016                 if (ret < 0)
7017                         continue;
7018                 BUG_ON(refs == 0);
7019
7020                 if (wc->stage == DROP_REFERENCE) {
7021                         if (refs == 1)
7022                                 goto reada;
7023
7024                         if (wc->level == 1 &&
7025                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7026                                 continue;
7027                         if (!wc->update_ref ||
7028                             generation <= root->root_key.offset)
7029                                 continue;
7030                         btrfs_node_key_to_cpu(eb, &key, slot);
7031                         ret = btrfs_comp_cpu_keys(&key,
7032                                                   &wc->update_progress);
7033                         if (ret < 0)
7034                                 continue;
7035                 } else {
7036                         if (wc->level == 1 &&
7037                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7038                                 continue;
7039                 }
7040 reada:
7041                 ret = readahead_tree_block(root, bytenr, blocksize,
7042                                            generation);
7043                 if (ret)
7044                         break;
7045                 nread++;
7046         }
7047         wc->reada_slot = slot;
7048 }
7049
7050 /*
7051  * helper to process tree block while walking down the tree.
7052  *
7053  * when wc->stage == UPDATE_BACKREF, this function updates
7054  * back refs for pointers in the block.
7055  *
7056  * NOTE: return value 1 means we should stop walking down.
7057  */
7058 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7059                                    struct btrfs_root *root,
7060                                    struct btrfs_path *path,
7061                                    struct walk_control *wc, int lookup_info)
7062 {
7063         int level = wc->level;
7064         struct extent_buffer *eb = path->nodes[level];
7065         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7066         int ret;
7067
7068         if (wc->stage == UPDATE_BACKREF &&
7069             btrfs_header_owner(eb) != root->root_key.objectid)
7070                 return 1;
7071
7072         /*
7073          * when reference count of tree block is 1, it won't increase
7074          * again. once full backref flag is set, we never clear it.
7075          */
7076         if (lookup_info &&
7077             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7078              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7079                 BUG_ON(!path->locks[level]);
7080                 ret = btrfs_lookup_extent_info(trans, root,
7081                                                eb->start, level, 1,
7082                                                &wc->refs[level],
7083                                                &wc->flags[level]);
7084                 BUG_ON(ret == -ENOMEM);
7085                 if (ret)
7086                         return ret;
7087                 BUG_ON(wc->refs[level] == 0);
7088         }
7089
7090         if (wc->stage == DROP_REFERENCE) {
7091                 if (wc->refs[level] > 1)
7092                         return 1;
7093
7094                 if (path->locks[level] && !wc->keep_locks) {
7095                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7096                         path->locks[level] = 0;
7097                 }
7098                 return 0;
7099         }
7100
7101         /* wc->stage == UPDATE_BACKREF */
7102         if (!(wc->flags[level] & flag)) {
7103                 BUG_ON(!path->locks[level]);
7104                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
7105                 BUG_ON(ret); /* -ENOMEM */
7106                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
7107                 BUG_ON(ret); /* -ENOMEM */
7108                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7109                                                   eb->len, flag,
7110                                                   btrfs_header_level(eb), 0);
7111                 BUG_ON(ret); /* -ENOMEM */
7112                 wc->flags[level] |= flag;
7113         }
7114
7115         /*
7116          * the block is shared by multiple trees, so it's not good to
7117          * keep the tree lock
7118          */
7119         if (path->locks[level] && level > 0) {
7120                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7121                 path->locks[level] = 0;
7122         }
7123         return 0;
7124 }
7125
7126 /*
7127  * helper to process tree block pointer.
7128  *
7129  * when wc->stage == DROP_REFERENCE, this function checks
7130  * reference count of the block pointed to. if the block
7131  * is shared and we need update back refs for the subtree
7132  * rooted at the block, this function changes wc->stage to
7133  * UPDATE_BACKREF. if the block is shared and there is no
7134  * need to update back, this function drops the reference
7135  * to the block.
7136  *
7137  * NOTE: return value 1 means we should stop walking down.
7138  */
7139 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
7140                                  struct btrfs_root *root,
7141                                  struct btrfs_path *path,
7142                                  struct walk_control *wc, int *lookup_info)
7143 {
7144         u64 bytenr;
7145         u64 generation;
7146         u64 parent;
7147         u32 blocksize;
7148         struct btrfs_key key;
7149         struct extent_buffer *next;
7150         int level = wc->level;
7151         int reada = 0;
7152         int ret = 0;
7153
7154         generation = btrfs_node_ptr_generation(path->nodes[level],
7155                                                path->slots[level]);
7156         /*
7157          * if the lower level block was created before the snapshot
7158          * was created, we know there is no need to update back refs
7159          * for the subtree
7160          */
7161         if (wc->stage == UPDATE_BACKREF &&
7162             generation <= root->root_key.offset) {
7163                 *lookup_info = 1;
7164                 return 1;
7165         }
7166
7167         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7168         blocksize = btrfs_level_size(root, level - 1);
7169
7170         next = btrfs_find_tree_block(root, bytenr, blocksize);
7171         if (!next) {
7172                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
7173                 if (!next)
7174                         return -ENOMEM;
7175                 reada = 1;
7176         }
7177         btrfs_tree_lock(next);
7178         btrfs_set_lock_blocking(next);
7179
7180         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7181                                        &wc->refs[level - 1],
7182                                        &wc->flags[level - 1]);
7183         if (ret < 0) {
7184                 btrfs_tree_unlock(next);
7185                 return ret;
7186         }
7187
7188         if (unlikely(wc->refs[level - 1] == 0)) {
7189                 btrfs_err(root->fs_info, "Missing references.");
7190                 BUG();
7191         }
7192         *lookup_info = 0;
7193
7194         if (wc->stage == DROP_REFERENCE) {
7195                 if (wc->refs[level - 1] > 1) {
7196                         if (level == 1 &&
7197                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7198                                 goto skip;
7199
7200                         if (!wc->update_ref ||
7201                             generation <= root->root_key.offset)
7202                                 goto skip;
7203
7204                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7205                                               path->slots[level]);
7206                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7207                         if (ret < 0)
7208                                 goto skip;
7209
7210                         wc->stage = UPDATE_BACKREF;
7211                         wc->shared_level = level - 1;
7212                 }
7213         } else {
7214                 if (level == 1 &&
7215                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7216                         goto skip;
7217         }
7218
7219         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7220                 btrfs_tree_unlock(next);
7221                 free_extent_buffer(next);
7222                 next = NULL;
7223                 *lookup_info = 1;
7224         }
7225
7226         if (!next) {
7227                 if (reada && level == 1)
7228                         reada_walk_down(trans, root, wc, path);
7229                 next = read_tree_block(root, bytenr, blocksize, generation);
7230                 if (!next || !extent_buffer_uptodate(next)) {
7231                         free_extent_buffer(next);
7232                         return -EIO;
7233                 }
7234                 btrfs_tree_lock(next);
7235                 btrfs_set_lock_blocking(next);
7236         }
7237
7238         level--;
7239         BUG_ON(level != btrfs_header_level(next));
7240         path->nodes[level] = next;
7241         path->slots[level] = 0;
7242         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7243         wc->level = level;
7244         if (wc->level == 1)
7245                 wc->reada_slot = 0;
7246         return 0;
7247 skip:
7248         wc->refs[level - 1] = 0;
7249         wc->flags[level - 1] = 0;
7250         if (wc->stage == DROP_REFERENCE) {
7251                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7252                         parent = path->nodes[level]->start;
7253                 } else {
7254                         BUG_ON(root->root_key.objectid !=
7255                                btrfs_header_owner(path->nodes[level]));
7256                         parent = 0;
7257                 }
7258
7259                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7260                                 root->root_key.objectid, level - 1, 0, 0);
7261                 BUG_ON(ret); /* -ENOMEM */
7262         }
7263         btrfs_tree_unlock(next);
7264         free_extent_buffer(next);
7265         *lookup_info = 1;
7266         return 1;
7267 }
7268
7269 /*
7270  * helper to process tree block while walking up the tree.
7271  *
7272  * when wc->stage == DROP_REFERENCE, this function drops
7273  * reference count on the block.
7274  *
7275  * when wc->stage == UPDATE_BACKREF, this function changes
7276  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7277  * to UPDATE_BACKREF previously while processing the block.
7278  *
7279  * NOTE: return value 1 means we should stop walking up.
7280  */
7281 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7282                                  struct btrfs_root *root,
7283                                  struct btrfs_path *path,
7284                                  struct walk_control *wc)
7285 {
7286         int ret;
7287         int level = wc->level;
7288         struct extent_buffer *eb = path->nodes[level];
7289         u64 parent = 0;
7290
7291         if (wc->stage == UPDATE_BACKREF) {
7292                 BUG_ON(wc->shared_level < level);
7293                 if (level < wc->shared_level)
7294                         goto out;
7295
7296                 ret = find_next_key(path, level + 1, &wc->update_progress);
7297                 if (ret > 0)
7298                         wc->update_ref = 0;
7299
7300                 wc->stage = DROP_REFERENCE;
7301                 wc->shared_level = -1;
7302                 path->slots[level] = 0;
7303
7304                 /*
7305                  * check reference count again if the block isn't locked.
7306                  * we should start walking down the tree again if reference
7307                  * count is one.
7308                  */
7309                 if (!path->locks[level]) {
7310                         BUG_ON(level == 0);
7311                         btrfs_tree_lock(eb);
7312                         btrfs_set_lock_blocking(eb);
7313                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7314
7315                         ret = btrfs_lookup_extent_info(trans, root,
7316                                                        eb->start, level, 1,
7317                                                        &wc->refs[level],
7318                                                        &wc->flags[level]);
7319                         if (ret < 0) {
7320                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7321                                 path->locks[level] = 0;
7322                                 return ret;
7323                         }
7324                         BUG_ON(wc->refs[level] == 0);
7325                         if (wc->refs[level] == 1) {
7326                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7327                                 path->locks[level] = 0;
7328                                 return 1;
7329                         }
7330                 }
7331         }
7332
7333         /* wc->stage == DROP_REFERENCE */
7334         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7335
7336         if (wc->refs[level] == 1) {
7337                 if (level == 0) {
7338                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7339                                 ret = btrfs_dec_ref(trans, root, eb, 1,
7340                                                     wc->for_reloc);
7341                         else
7342                                 ret = btrfs_dec_ref(trans, root, eb, 0,
7343                                                     wc->for_reloc);
7344                         BUG_ON(ret); /* -ENOMEM */
7345                 }
7346                 /* make block locked assertion in clean_tree_block happy */
7347                 if (!path->locks[level] &&
7348                     btrfs_header_generation(eb) == trans->transid) {
7349                         btrfs_tree_lock(eb);
7350                         btrfs_set_lock_blocking(eb);
7351                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7352                 }
7353                 clean_tree_block(trans, root, eb);
7354         }
7355
7356         if (eb == root->node) {
7357                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7358                         parent = eb->start;
7359                 else
7360                         BUG_ON(root->root_key.objectid !=
7361                                btrfs_header_owner(eb));
7362         } else {
7363                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7364                         parent = path->nodes[level + 1]->start;
7365                 else
7366                         BUG_ON(root->root_key.objectid !=
7367                                btrfs_header_owner(path->nodes[level + 1]));
7368         }
7369
7370         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7371 out:
7372         wc->refs[level] = 0;
7373         wc->flags[level] = 0;
7374         return 0;
7375 }
7376
7377 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7378                                    struct btrfs_root *root,
7379                                    struct btrfs_path *path,
7380                                    struct walk_control *wc)
7381 {
7382         int level = wc->level;
7383         int lookup_info = 1;
7384         int ret;
7385
7386         while (level >= 0) {
7387                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
7388                 if (ret > 0)
7389                         break;
7390
7391                 if (level == 0)
7392                         break;
7393
7394                 if (path->slots[level] >=
7395                     btrfs_header_nritems(path->nodes[level]))
7396                         break;
7397
7398                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
7399                 if (ret > 0) {
7400                         path->slots[level]++;
7401                         continue;
7402                 } else if (ret < 0)
7403                         return ret;
7404                 level = wc->level;
7405         }
7406         return 0;
7407 }
7408
7409 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
7410                                  struct btrfs_root *root,
7411                                  struct btrfs_path *path,
7412                                  struct walk_control *wc, int max_level)
7413 {
7414         int level = wc->level;
7415         int ret;
7416
7417         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
7418         while (level < max_level && path->nodes[level]) {
7419                 wc->level = level;
7420                 if (path->slots[level] + 1 <
7421                     btrfs_header_nritems(path->nodes[level])) {
7422                         path->slots[level]++;
7423                         return 0;
7424                 } else {
7425                         ret = walk_up_proc(trans, root, path, wc);
7426                         if (ret > 0)
7427                                 return 0;
7428
7429                         if (path->locks[level]) {
7430                                 btrfs_tree_unlock_rw(path->nodes[level],
7431                                                      path->locks[level]);
7432                                 path->locks[level] = 0;
7433                         }
7434                         free_extent_buffer(path->nodes[level]);
7435                         path->nodes[level] = NULL;
7436                         level++;
7437                 }
7438         }
7439         return 1;
7440 }
7441
7442 /*
7443  * drop a subvolume tree.
7444  *
7445  * this function traverses the tree freeing any blocks that only
7446  * referenced by the tree.
7447  *
7448  * when a shared tree block is found. this function decreases its
7449  * reference count by one. if update_ref is true, this function
7450  * also make sure backrefs for the shared block and all lower level
7451  * blocks are properly updated.
7452  *
7453  * If called with for_reloc == 0, may exit early with -EAGAIN
7454  */
7455 int btrfs_drop_snapshot(struct btrfs_root *root,
7456                          struct btrfs_block_rsv *block_rsv, int update_ref,
7457                          int for_reloc)
7458 {
7459         struct btrfs_path *path;
7460         struct btrfs_trans_handle *trans;
7461         struct btrfs_root *tree_root = root->fs_info->tree_root;
7462         struct btrfs_root_item *root_item = &root->root_item;
7463         struct walk_control *wc;
7464         struct btrfs_key key;
7465         int err = 0;
7466         int ret;
7467         int level;
7468
7469         path = btrfs_alloc_path();
7470         if (!path) {
7471                 err = -ENOMEM;
7472                 goto out;
7473         }
7474
7475         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7476         if (!wc) {
7477                 btrfs_free_path(path);
7478                 err = -ENOMEM;
7479                 goto out;
7480         }
7481
7482         trans = btrfs_start_transaction(tree_root, 0);
7483         if (IS_ERR(trans)) {
7484                 err = PTR_ERR(trans);
7485                 goto out_free;
7486         }
7487
7488         if (block_rsv)
7489                 trans->block_rsv = block_rsv;
7490
7491         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
7492                 level = btrfs_header_level(root->node);
7493                 path->nodes[level] = btrfs_lock_root_node(root);
7494                 btrfs_set_lock_blocking(path->nodes[level]);
7495                 path->slots[level] = 0;
7496                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7497                 memset(&wc->update_progress, 0,
7498                        sizeof(wc->update_progress));
7499         } else {
7500                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
7501                 memcpy(&wc->update_progress, &key,
7502                        sizeof(wc->update_progress));
7503
7504                 level = root_item->drop_level;
7505                 BUG_ON(level == 0);
7506                 path->lowest_level = level;
7507                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
7508                 path->lowest_level = 0;
7509                 if (ret < 0) {
7510                         err = ret;
7511                         goto out_end_trans;
7512                 }
7513                 WARN_ON(ret > 0);
7514
7515                 /*
7516                  * unlock our path, this is safe because only this
7517                  * function is allowed to delete this snapshot
7518                  */
7519                 btrfs_unlock_up_safe(path, 0);
7520
7521                 level = btrfs_header_level(root->node);
7522                 while (1) {
7523                         btrfs_tree_lock(path->nodes[level]);
7524                         btrfs_set_lock_blocking(path->nodes[level]);
7525
7526                         ret = btrfs_lookup_extent_info(trans, root,
7527                                                 path->nodes[level]->start,
7528                                                 level, 1, &wc->refs[level],
7529                                                 &wc->flags[level]);
7530                         if (ret < 0) {
7531                                 err = ret;
7532                                 goto out_end_trans;
7533                         }
7534                         BUG_ON(wc->refs[level] == 0);
7535
7536                         if (level == root_item->drop_level)
7537                                 break;
7538
7539                         btrfs_tree_unlock(path->nodes[level]);
7540                         WARN_ON(wc->refs[level] != 1);
7541                         level--;
7542                 }
7543         }
7544
7545         wc->level = level;
7546         wc->shared_level = -1;
7547         wc->stage = DROP_REFERENCE;
7548         wc->update_ref = update_ref;
7549         wc->keep_locks = 0;
7550         wc->for_reloc = for_reloc;
7551         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7552
7553         while (1) {
7554                 if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
7555                         pr_debug("btrfs: drop snapshot early exit\n");
7556                         err = -EAGAIN;
7557                         goto out_end_trans;
7558                 }
7559
7560                 ret = walk_down_tree(trans, root, path, wc);
7561                 if (ret < 0) {
7562                         err = ret;
7563                         break;
7564                 }
7565
7566                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7567                 if (ret < 0) {
7568                         err = ret;
7569                         break;
7570                 }
7571
7572                 if (ret > 0) {
7573                         BUG_ON(wc->stage != DROP_REFERENCE);
7574                         break;
7575                 }
7576
7577                 if (wc->stage == DROP_REFERENCE) {
7578                         level = wc->level;
7579                         btrfs_node_key(path->nodes[level],
7580                                        &root_item->drop_progress,
7581                                        path->slots[level]);
7582                         root_item->drop_level = level;
7583                 }
7584
7585                 BUG_ON(wc->level == 0);
7586                 if (btrfs_should_end_transaction(trans, tree_root)) {
7587                         ret = btrfs_update_root(trans, tree_root,
7588                                                 &root->root_key,
7589                                                 root_item);
7590                         if (ret) {
7591                                 btrfs_abort_transaction(trans, tree_root, ret);
7592                                 err = ret;
7593                                 goto out_end_trans;
7594                         }
7595
7596                         btrfs_end_transaction_throttle(trans, tree_root);
7597                         trans = btrfs_start_transaction(tree_root, 0);
7598                         if (IS_ERR(trans)) {
7599                                 err = PTR_ERR(trans);
7600                                 goto out_free;
7601                         }
7602                         if (block_rsv)
7603                                 trans->block_rsv = block_rsv;
7604                 }
7605         }
7606         btrfs_release_path(path);
7607         if (err)
7608                 goto out_end_trans;
7609
7610         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7611         if (ret) {
7612                 btrfs_abort_transaction(trans, tree_root, ret);
7613                 goto out_end_trans;
7614         }
7615
7616         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7617                 ret = btrfs_find_root(tree_root, &root->root_key, path,
7618                                       NULL, NULL);
7619                 if (ret < 0) {
7620                         btrfs_abort_transaction(trans, tree_root, ret);
7621                         err = ret;
7622                         goto out_end_trans;
7623                 } else if (ret > 0) {
7624                         /* if we fail to delete the orphan item this time
7625                          * around, it'll get picked up the next time.
7626                          *
7627                          * The most common failure here is just -ENOENT.
7628                          */
7629                         btrfs_del_orphan_item(trans, tree_root,
7630                                               root->root_key.objectid);
7631                 }
7632         }
7633
7634         if (root->in_radix) {
7635                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
7636         } else {
7637                 free_extent_buffer(root->node);
7638                 free_extent_buffer(root->commit_root);
7639                 btrfs_put_fs_root(root);
7640         }
7641 out_end_trans:
7642         btrfs_end_transaction_throttle(trans, tree_root);
7643 out_free:
7644         kfree(wc);
7645         btrfs_free_path(path);
7646 out:
7647         if (err)
7648                 btrfs_std_error(root->fs_info, err);
7649         return err;
7650 }
7651
7652 /*
7653  * drop subtree rooted at tree block 'node'.
7654  *
7655  * NOTE: this function will unlock and release tree block 'node'
7656  * only used by relocation code
7657  */
7658 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7659                         struct btrfs_root *root,
7660                         struct extent_buffer *node,
7661                         struct extent_buffer *parent)
7662 {
7663         struct btrfs_path *path;
7664         struct walk_control *wc;
7665         int level;
7666         int parent_level;
7667         int ret = 0;
7668         int wret;
7669
7670         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7671
7672         path = btrfs_alloc_path();
7673         if (!path)
7674                 return -ENOMEM;
7675
7676         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7677         if (!wc) {
7678                 btrfs_free_path(path);
7679                 return -ENOMEM;
7680         }
7681
7682         btrfs_assert_tree_locked(parent);
7683         parent_level = btrfs_header_level(parent);
7684         extent_buffer_get(parent);
7685         path->nodes[parent_level] = parent;
7686         path->slots[parent_level] = btrfs_header_nritems(parent);
7687
7688         btrfs_assert_tree_locked(node);
7689         level = btrfs_header_level(node);
7690         path->nodes[level] = node;
7691         path->slots[level] = 0;
7692         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7693
7694         wc->refs[parent_level] = 1;
7695         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7696         wc->level = level;
7697         wc->shared_level = -1;
7698         wc->stage = DROP_REFERENCE;
7699         wc->update_ref = 0;
7700         wc->keep_locks = 1;
7701         wc->for_reloc = 1;
7702         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7703
7704         while (1) {
7705                 wret = walk_down_tree(trans, root, path, wc);
7706                 if (wret < 0) {
7707                         ret = wret;
7708                         break;
7709                 }
7710
7711                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7712                 if (wret < 0)
7713                         ret = wret;
7714                 if (wret != 0)
7715                         break;
7716         }
7717
7718         kfree(wc);
7719         btrfs_free_path(path);
7720         return ret;
7721 }
7722
7723 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7724 {
7725         u64 num_devices;
7726         u64 stripped;
7727
7728         /*
7729          * if restripe for this chunk_type is on pick target profile and
7730          * return, otherwise do the usual balance
7731          */
7732         stripped = get_restripe_target(root->fs_info, flags);
7733         if (stripped)
7734                 return extended_to_chunk(stripped);
7735
7736         /*
7737          * we add in the count of missing devices because we want
7738          * to make sure that any RAID levels on a degraded FS
7739          * continue to be honored.
7740          */
7741         num_devices = root->fs_info->fs_devices->rw_devices +
7742                 root->fs_info->fs_devices->missing_devices;
7743
7744         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7745                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
7746                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7747
7748         if (num_devices == 1) {
7749                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7750                 stripped = flags & ~stripped;
7751
7752                 /* turn raid0 into single device chunks */
7753                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7754                         return stripped;
7755
7756                 /* turn mirroring into duplication */
7757                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7758                              BTRFS_BLOCK_GROUP_RAID10))
7759                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7760         } else {
7761                 /* they already had raid on here, just return */
7762                 if (flags & stripped)
7763                         return flags;
7764
7765                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7766                 stripped = flags & ~stripped;
7767
7768                 /* switch duplicated blocks with raid1 */
7769                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7770                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7771
7772                 /* this is drive concat, leave it alone */
7773         }
7774
7775         return flags;
7776 }
7777
7778 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7779 {
7780         struct btrfs_space_info *sinfo = cache->space_info;
7781         u64 num_bytes;
7782         u64 min_allocable_bytes;
7783         int ret = -ENOSPC;
7784
7785
7786         /*
7787          * We need some metadata space and system metadata space for
7788          * allocating chunks in some corner cases until we force to set
7789          * it to be readonly.
7790          */
7791         if ((sinfo->flags &
7792              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7793             !force)
7794                 min_allocable_bytes = 1 * 1024 * 1024;
7795         else
7796                 min_allocable_bytes = 0;
7797
7798         spin_lock(&sinfo->lock);
7799         spin_lock(&cache->lock);
7800
7801         if (cache->ro) {
7802                 ret = 0;
7803                 goto out;
7804         }
7805
7806         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7807                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7808
7809         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7810             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7811             min_allocable_bytes <= sinfo->total_bytes) {
7812                 sinfo->bytes_readonly += num_bytes;
7813                 cache->ro = 1;
7814                 ret = 0;
7815         }
7816 out:
7817         spin_unlock(&cache->lock);
7818         spin_unlock(&sinfo->lock);
7819         return ret;
7820 }
7821
7822 int btrfs_set_block_group_ro(struct btrfs_root *root,
7823                              struct btrfs_block_group_cache *cache)
7824
7825 {
7826         struct btrfs_trans_handle *trans;
7827         u64 alloc_flags;
7828         int ret;
7829
7830         BUG_ON(cache->ro);
7831
7832         trans = btrfs_join_transaction(root);
7833         if (IS_ERR(trans))
7834                 return PTR_ERR(trans);
7835
7836         alloc_flags = update_block_group_flags(root, cache->flags);
7837         if (alloc_flags != cache->flags) {
7838                 ret = do_chunk_alloc(trans, root, alloc_flags,
7839                                      CHUNK_ALLOC_FORCE);
7840                 if (ret < 0)
7841                         goto out;
7842         }
7843
7844         ret = set_block_group_ro(cache, 0);
7845         if (!ret)
7846                 goto out;
7847         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7848         ret = do_chunk_alloc(trans, root, alloc_flags,
7849                              CHUNK_ALLOC_FORCE);
7850         if (ret < 0)
7851                 goto out;
7852         ret = set_block_group_ro(cache, 0);
7853 out:
7854         btrfs_end_transaction(trans, root);
7855         return ret;
7856 }
7857
7858 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7859                             struct btrfs_root *root, u64 type)
7860 {
7861         u64 alloc_flags = get_alloc_profile(root, type);
7862         return do_chunk_alloc(trans, root, alloc_flags,
7863                               CHUNK_ALLOC_FORCE);
7864 }
7865
7866 /*
7867  * helper to account the unused space of all the readonly block group in the
7868  * list. takes mirrors into account.
7869  */
7870 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7871 {
7872         struct btrfs_block_group_cache *block_group;
7873         u64 free_bytes = 0;
7874         int factor;
7875
7876         list_for_each_entry(block_group, groups_list, list) {
7877                 spin_lock(&block_group->lock);
7878
7879                 if (!block_group->ro) {
7880                         spin_unlock(&block_group->lock);
7881                         continue;
7882                 }
7883
7884                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7885                                           BTRFS_BLOCK_GROUP_RAID10 |
7886                                           BTRFS_BLOCK_GROUP_DUP))
7887                         factor = 2;
7888                 else
7889                         factor = 1;
7890
7891                 free_bytes += (block_group->key.offset -
7892                                btrfs_block_group_used(&block_group->item)) *
7893                                factor;
7894
7895                 spin_unlock(&block_group->lock);
7896         }
7897
7898         return free_bytes;
7899 }
7900
7901 /*
7902  * helper to account the unused space of all the readonly block group in the
7903  * space_info. takes mirrors into account.
7904  */
7905 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7906 {
7907         int i;
7908         u64 free_bytes = 0;
7909
7910         spin_lock(&sinfo->lock);
7911
7912         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7913                 if (!list_empty(&sinfo->block_groups[i]))
7914                         free_bytes += __btrfs_get_ro_block_group_free_space(
7915                                                 &sinfo->block_groups[i]);
7916
7917         spin_unlock(&sinfo->lock);
7918
7919         return free_bytes;
7920 }
7921
7922 void btrfs_set_block_group_rw(struct btrfs_root *root,
7923                               struct btrfs_block_group_cache *cache)
7924 {
7925         struct btrfs_space_info *sinfo = cache->space_info;
7926         u64 num_bytes;
7927
7928         BUG_ON(!cache->ro);
7929
7930         spin_lock(&sinfo->lock);
7931         spin_lock(&cache->lock);
7932         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7933                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7934         sinfo->bytes_readonly -= num_bytes;
7935         cache->ro = 0;
7936         spin_unlock(&cache->lock);
7937         spin_unlock(&sinfo->lock);
7938 }
7939
7940 /*
7941  * checks to see if its even possible to relocate this block group.
7942  *
7943  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7944  * ok to go ahead and try.
7945  */
7946 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7947 {
7948         struct btrfs_block_group_cache *block_group;
7949         struct btrfs_space_info *space_info;
7950         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7951         struct btrfs_device *device;
7952         u64 min_free;
7953         u64 dev_min = 1;
7954         u64 dev_nr = 0;
7955         u64 target;
7956         int index;
7957         int full = 0;
7958         int ret = 0;
7959
7960         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7961
7962         /* odd, couldn't find the block group, leave it alone */
7963         if (!block_group)
7964                 return -1;
7965
7966         min_free = btrfs_block_group_used(&block_group->item);
7967
7968         /* no bytes used, we're good */
7969         if (!min_free)
7970                 goto out;
7971
7972         space_info = block_group->space_info;
7973         spin_lock(&space_info->lock);
7974
7975         full = space_info->full;
7976
7977         /*
7978          * if this is the last block group we have in this space, we can't
7979          * relocate it unless we're able to allocate a new chunk below.
7980          *
7981          * Otherwise, we need to make sure we have room in the space to handle
7982          * all of the extents from this block group.  If we can, we're good
7983          */
7984         if ((space_info->total_bytes != block_group->key.offset) &&
7985             (space_info->bytes_used + space_info->bytes_reserved +
7986              space_info->bytes_pinned + space_info->bytes_readonly +
7987              min_free < space_info->total_bytes)) {
7988                 spin_unlock(&space_info->lock);
7989                 goto out;
7990         }
7991         spin_unlock(&space_info->lock);
7992
7993         /*
7994          * ok we don't have enough space, but maybe we have free space on our
7995          * devices to allocate new chunks for relocation, so loop through our
7996          * alloc devices and guess if we have enough space.  if this block
7997          * group is going to be restriped, run checks against the target
7998          * profile instead of the current one.
7999          */
8000         ret = -1;
8001
8002         /*
8003          * index:
8004          *      0: raid10
8005          *      1: raid1
8006          *      2: dup
8007          *      3: raid0
8008          *      4: single
8009          */
8010         target = get_restripe_target(root->fs_info, block_group->flags);
8011         if (target) {
8012                 index = __get_raid_index(extended_to_chunk(target));
8013         } else {
8014                 /*
8015                  * this is just a balance, so if we were marked as full
8016                  * we know there is no space for a new chunk
8017                  */
8018                 if (full)
8019                         goto out;
8020
8021                 index = get_block_group_index(block_group);
8022         }
8023
8024         if (index == BTRFS_RAID_RAID10) {
8025                 dev_min = 4;
8026                 /* Divide by 2 */
8027                 min_free >>= 1;
8028         } else if (index == BTRFS_RAID_RAID1) {
8029                 dev_min = 2;
8030         } else if (index == BTRFS_RAID_DUP) {
8031                 /* Multiply by 2 */
8032                 min_free <<= 1;
8033         } else if (index == BTRFS_RAID_RAID0) {
8034                 dev_min = fs_devices->rw_devices;
8035                 do_div(min_free, dev_min);
8036         }
8037
8038         mutex_lock(&root->fs_info->chunk_mutex);
8039         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8040                 u64 dev_offset;
8041
8042                 /*
8043                  * check to make sure we can actually find a chunk with enough
8044                  * space to fit our block group in.
8045                  */
8046                 if (device->total_bytes > device->bytes_used + min_free &&
8047                     !device->is_tgtdev_for_dev_replace) {
8048                         ret = find_free_dev_extent(device, min_free,
8049                                                    &dev_offset, NULL);
8050                         if (!ret)
8051                                 dev_nr++;
8052
8053                         if (dev_nr >= dev_min)
8054                                 break;
8055
8056                         ret = -1;
8057                 }
8058         }
8059         mutex_unlock(&root->fs_info->chunk_mutex);
8060 out:
8061         btrfs_put_block_group(block_group);
8062         return ret;
8063 }
8064
8065 static int find_first_block_group(struct btrfs_root *root,
8066                 struct btrfs_path *path, struct btrfs_key *key)
8067 {
8068         int ret = 0;
8069         struct btrfs_key found_key;
8070         struct extent_buffer *leaf;
8071         int slot;
8072
8073         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
8074         if (ret < 0)
8075                 goto out;
8076
8077         while (1) {
8078                 slot = path->slots[0];
8079                 leaf = path->nodes[0];
8080                 if (slot >= btrfs_header_nritems(leaf)) {
8081                         ret = btrfs_next_leaf(root, path);
8082                         if (ret == 0)
8083                                 continue;
8084                         if (ret < 0)
8085                                 goto out;
8086                         break;
8087                 }
8088                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
8089
8090                 if (found_key.objectid >= key->objectid &&
8091                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
8092                         ret = 0;
8093                         goto out;
8094                 }
8095                 path->slots[0]++;
8096         }
8097 out:
8098         return ret;
8099 }
8100
8101 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
8102 {
8103         struct btrfs_block_group_cache *block_group;
8104         u64 last = 0;
8105
8106         while (1) {
8107                 struct inode *inode;
8108
8109                 block_group = btrfs_lookup_first_block_group(info, last);
8110                 while (block_group) {
8111                         spin_lock(&block_group->lock);
8112                         if (block_group->iref)
8113                                 break;
8114                         spin_unlock(&block_group->lock);
8115                         block_group = next_block_group(info->tree_root,
8116                                                        block_group);
8117                 }
8118                 if (!block_group) {
8119                         if (last == 0)
8120                                 break;
8121                         last = 0;
8122                         continue;
8123                 }
8124
8125                 inode = block_group->inode;
8126                 block_group->iref = 0;
8127                 block_group->inode = NULL;
8128                 spin_unlock(&block_group->lock);
8129                 iput(inode);
8130                 last = block_group->key.objectid + block_group->key.offset;
8131                 btrfs_put_block_group(block_group);
8132         }
8133 }
8134
8135 int btrfs_free_block_groups(struct btrfs_fs_info *info)
8136 {
8137         struct btrfs_block_group_cache *block_group;
8138         struct btrfs_space_info *space_info;
8139         struct btrfs_caching_control *caching_ctl;
8140         struct rb_node *n;
8141
8142         down_write(&info->extent_commit_sem);
8143         while (!list_empty(&info->caching_block_groups)) {
8144                 caching_ctl = list_entry(info->caching_block_groups.next,
8145                                          struct btrfs_caching_control, list);
8146                 list_del(&caching_ctl->list);
8147                 put_caching_control(caching_ctl);
8148         }
8149         up_write(&info->extent_commit_sem);
8150
8151         spin_lock(&info->block_group_cache_lock);
8152         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8153                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8154                                        cache_node);
8155                 rb_erase(&block_group->cache_node,
8156                          &info->block_group_cache_tree);
8157                 spin_unlock(&info->block_group_cache_lock);
8158
8159                 down_write(&block_group->space_info->groups_sem);
8160                 list_del(&block_group->list);
8161                 up_write(&block_group->space_info->groups_sem);
8162
8163                 if (block_group->cached == BTRFS_CACHE_STARTED)
8164                         wait_block_group_cache_done(block_group);
8165
8166                 /*
8167                  * We haven't cached this block group, which means we could
8168                  * possibly have excluded extents on this block group.
8169                  */
8170                 if (block_group->cached == BTRFS_CACHE_NO)
8171                         free_excluded_extents(info->extent_root, block_group);
8172
8173                 btrfs_remove_free_space_cache(block_group);
8174                 btrfs_put_block_group(block_group);
8175
8176                 spin_lock(&info->block_group_cache_lock);
8177         }
8178         spin_unlock(&info->block_group_cache_lock);
8179
8180         /* now that all the block groups are freed, go through and
8181          * free all the space_info structs.  This is only called during
8182          * the final stages of unmount, and so we know nobody is
8183          * using them.  We call synchronize_rcu() once before we start,
8184          * just to be on the safe side.
8185          */
8186         synchronize_rcu();
8187
8188         release_global_block_rsv(info);
8189
8190         while(!list_empty(&info->space_info)) {
8191                 space_info = list_entry(info->space_info.next,
8192                                         struct btrfs_space_info,
8193                                         list);
8194                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8195                         if (space_info->bytes_pinned > 0 ||
8196                             space_info->bytes_reserved > 0 ||
8197                             space_info->bytes_may_use > 0) {
8198                                 WARN_ON(1);
8199                                 dump_space_info(space_info, 0, 0);
8200                         }
8201                 }
8202                 percpu_counter_destroy(&space_info->total_bytes_pinned);
8203                 list_del(&space_info->list);
8204                 kfree(space_info);
8205         }
8206         return 0;
8207 }
8208
8209 static void __link_block_group(struct btrfs_space_info *space_info,
8210                                struct btrfs_block_group_cache *cache)
8211 {
8212         int index = get_block_group_index(cache);
8213
8214         down_write(&space_info->groups_sem);
8215         list_add_tail(&cache->list, &space_info->block_groups[index]);
8216         up_write(&space_info->groups_sem);
8217 }
8218
8219 int btrfs_read_block_groups(struct btrfs_root *root)
8220 {
8221         struct btrfs_path *path;
8222         int ret;
8223         struct btrfs_block_group_cache *cache;
8224         struct btrfs_fs_info *info = root->fs_info;
8225         struct btrfs_space_info *space_info;
8226         struct btrfs_key key;
8227         struct btrfs_key found_key;
8228         struct extent_buffer *leaf;
8229         int need_clear = 0;
8230         u64 cache_gen;
8231
8232         root = info->extent_root;
8233         key.objectid = 0;
8234         key.offset = 0;
8235         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
8236         path = btrfs_alloc_path();
8237         if (!path)
8238                 return -ENOMEM;
8239         path->reada = 1;
8240
8241         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
8242         if (btrfs_test_opt(root, SPACE_CACHE) &&
8243             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
8244                 need_clear = 1;
8245         if (btrfs_test_opt(root, CLEAR_CACHE))
8246                 need_clear = 1;
8247
8248         while (1) {
8249                 ret = find_first_block_group(root, path, &key);
8250                 if (ret > 0)
8251                         break;
8252                 if (ret != 0)
8253                         goto error;
8254                 leaf = path->nodes[0];
8255                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8256                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
8257                 if (!cache) {
8258                         ret = -ENOMEM;
8259                         goto error;
8260                 }
8261                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8262                                                 GFP_NOFS);
8263                 if (!cache->free_space_ctl) {
8264                         kfree(cache);
8265                         ret = -ENOMEM;
8266                         goto error;
8267                 }
8268
8269                 atomic_set(&cache->count, 1);
8270                 spin_lock_init(&cache->lock);
8271                 cache->fs_info = info;
8272                 INIT_LIST_HEAD(&cache->list);
8273                 INIT_LIST_HEAD(&cache->cluster_list);
8274
8275                 if (need_clear) {
8276                         /*
8277                          * When we mount with old space cache, we need to
8278                          * set BTRFS_DC_CLEAR and set dirty flag.
8279                          *
8280                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
8281                          *    truncate the old free space cache inode and
8282                          *    setup a new one.
8283                          * b) Setting 'dirty flag' makes sure that we flush
8284                          *    the new space cache info onto disk.
8285                          */
8286                         cache->disk_cache_state = BTRFS_DC_CLEAR;
8287                         if (btrfs_test_opt(root, SPACE_CACHE))
8288                                 cache->dirty = 1;
8289                 }
8290
8291                 read_extent_buffer(leaf, &cache->item,
8292                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
8293                                    sizeof(cache->item));
8294                 memcpy(&cache->key, &found_key, sizeof(found_key));
8295
8296                 key.objectid = found_key.objectid + found_key.offset;
8297                 btrfs_release_path(path);
8298                 cache->flags = btrfs_block_group_flags(&cache->item);
8299                 cache->sectorsize = root->sectorsize;
8300                 cache->full_stripe_len = btrfs_full_stripe_len(root,
8301                                                &root->fs_info->mapping_tree,
8302                                                found_key.objectid);
8303                 btrfs_init_free_space_ctl(cache);
8304
8305                 /*
8306                  * We need to exclude the super stripes now so that the space
8307                  * info has super bytes accounted for, otherwise we'll think
8308                  * we have more space than we actually do.
8309                  */
8310                 ret = exclude_super_stripes(root, cache);
8311                 if (ret) {
8312                         /*
8313                          * We may have excluded something, so call this just in
8314                          * case.
8315                          */
8316                         free_excluded_extents(root, cache);
8317                         kfree(cache->free_space_ctl);
8318                         kfree(cache);
8319                         goto error;
8320                 }
8321
8322                 /*
8323                  * check for two cases, either we are full, and therefore
8324                  * don't need to bother with the caching work since we won't
8325                  * find any space, or we are empty, and we can just add all
8326                  * the space in and be done with it.  This saves us _alot_ of
8327                  * time, particularly in the full case.
8328                  */
8329                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
8330                         cache->last_byte_to_unpin = (u64)-1;
8331                         cache->cached = BTRFS_CACHE_FINISHED;
8332                         free_excluded_extents(root, cache);
8333                 } else if (btrfs_block_group_used(&cache->item) == 0) {
8334                         cache->last_byte_to_unpin = (u64)-1;
8335                         cache->cached = BTRFS_CACHE_FINISHED;
8336                         add_new_free_space(cache, root->fs_info,
8337                                            found_key.objectid,
8338                                            found_key.objectid +
8339                                            found_key.offset);
8340                         free_excluded_extents(root, cache);
8341                 }
8342
8343                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8344                 if (ret) {
8345                         btrfs_remove_free_space_cache(cache);
8346                         btrfs_put_block_group(cache);
8347                         goto error;
8348                 }
8349
8350                 ret = update_space_info(info, cache->flags, found_key.offset,
8351                                         btrfs_block_group_used(&cache->item),
8352                                         &space_info);
8353                 if (ret) {
8354                         btrfs_remove_free_space_cache(cache);
8355                         spin_lock(&info->block_group_cache_lock);
8356                         rb_erase(&cache->cache_node,
8357                                  &info->block_group_cache_tree);
8358                         spin_unlock(&info->block_group_cache_lock);
8359                         btrfs_put_block_group(cache);
8360                         goto error;
8361                 }
8362
8363                 cache->space_info = space_info;
8364                 spin_lock(&cache->space_info->lock);
8365                 cache->space_info->bytes_readonly += cache->bytes_super;
8366                 spin_unlock(&cache->space_info->lock);
8367
8368                 __link_block_group(space_info, cache);
8369
8370                 set_avail_alloc_bits(root->fs_info, cache->flags);
8371                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8372                         set_block_group_ro(cache, 1);
8373         }
8374
8375         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8376                 if (!(get_alloc_profile(root, space_info->flags) &
8377                       (BTRFS_BLOCK_GROUP_RAID10 |
8378                        BTRFS_BLOCK_GROUP_RAID1 |
8379                        BTRFS_BLOCK_GROUP_RAID5 |
8380                        BTRFS_BLOCK_GROUP_RAID6 |
8381                        BTRFS_BLOCK_GROUP_DUP)))
8382                         continue;
8383                 /*
8384                  * avoid allocating from un-mirrored block group if there are
8385                  * mirrored block groups.
8386                  */
8387                 list_for_each_entry(cache, &space_info->block_groups[3], list)
8388                         set_block_group_ro(cache, 1);
8389                 list_for_each_entry(cache, &space_info->block_groups[4], list)
8390                         set_block_group_ro(cache, 1);
8391         }
8392
8393         init_global_block_rsv(info);
8394         ret = 0;
8395 error:
8396         btrfs_free_path(path);
8397         return ret;
8398 }
8399
8400 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
8401                                        struct btrfs_root *root)
8402 {
8403         struct btrfs_block_group_cache *block_group, *tmp;
8404         struct btrfs_root *extent_root = root->fs_info->extent_root;
8405         struct btrfs_block_group_item item;
8406         struct btrfs_key key;
8407         int ret = 0;
8408
8409         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
8410                                  new_bg_list) {
8411                 list_del_init(&block_group->new_bg_list);
8412
8413                 if (ret)
8414                         continue;
8415
8416                 spin_lock(&block_group->lock);
8417                 memcpy(&item, &block_group->item, sizeof(item));
8418                 memcpy(&key, &block_group->key, sizeof(key));
8419                 spin_unlock(&block_group->lock);
8420
8421                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
8422                                         sizeof(item));
8423                 if (ret)
8424                         btrfs_abort_transaction(trans, extent_root, ret);
8425         }
8426 }
8427
8428 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8429                            struct btrfs_root *root, u64 bytes_used,
8430                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8431                            u64 size)
8432 {
8433         int ret;
8434         struct btrfs_root *extent_root;
8435         struct btrfs_block_group_cache *cache;
8436
8437         extent_root = root->fs_info->extent_root;
8438
8439         root->fs_info->last_trans_log_full_commit = trans->transid;
8440
8441         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8442         if (!cache)
8443                 return -ENOMEM;
8444         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8445                                         GFP_NOFS);
8446         if (!cache->free_space_ctl) {
8447                 kfree(cache);
8448                 return -ENOMEM;
8449         }
8450
8451         cache->key.objectid = chunk_offset;
8452         cache->key.offset = size;
8453         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8454         cache->sectorsize = root->sectorsize;
8455         cache->fs_info = root->fs_info;
8456         cache->full_stripe_len = btrfs_full_stripe_len(root,
8457                                                &root->fs_info->mapping_tree,
8458                                                chunk_offset);
8459
8460         atomic_set(&cache->count, 1);
8461         spin_lock_init(&cache->lock);
8462         INIT_LIST_HEAD(&cache->list);
8463         INIT_LIST_HEAD(&cache->cluster_list);
8464         INIT_LIST_HEAD(&cache->new_bg_list);
8465
8466         btrfs_init_free_space_ctl(cache);
8467
8468         btrfs_set_block_group_used(&cache->item, bytes_used);
8469         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8470         cache->flags = type;
8471         btrfs_set_block_group_flags(&cache->item, type);
8472
8473         cache->last_byte_to_unpin = (u64)-1;
8474         cache->cached = BTRFS_CACHE_FINISHED;
8475         ret = exclude_super_stripes(root, cache);
8476         if (ret) {
8477                 /*
8478                  * We may have excluded something, so call this just in
8479                  * case.
8480                  */
8481                 free_excluded_extents(root, cache);
8482                 kfree(cache->free_space_ctl);
8483                 kfree(cache);
8484                 return ret;
8485         }
8486
8487         add_new_free_space(cache, root->fs_info, chunk_offset,
8488                            chunk_offset + size);
8489
8490         free_excluded_extents(root, cache);
8491
8492         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8493         if (ret) {
8494                 btrfs_remove_free_space_cache(cache);
8495                 btrfs_put_block_group(cache);
8496                 return ret;
8497         }
8498
8499         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8500                                 &cache->space_info);
8501         if (ret) {
8502                 btrfs_remove_free_space_cache(cache);
8503                 spin_lock(&root->fs_info->block_group_cache_lock);
8504                 rb_erase(&cache->cache_node,
8505                          &root->fs_info->block_group_cache_tree);
8506                 spin_unlock(&root->fs_info->block_group_cache_lock);
8507                 btrfs_put_block_group(cache);
8508                 return ret;
8509         }
8510         update_global_block_rsv(root->fs_info);
8511
8512         spin_lock(&cache->space_info->lock);
8513         cache->space_info->bytes_readonly += cache->bytes_super;
8514         spin_unlock(&cache->space_info->lock);
8515
8516         __link_block_group(cache->space_info, cache);
8517
8518         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
8519
8520         set_avail_alloc_bits(extent_root->fs_info, type);
8521
8522         return 0;
8523 }
8524
8525 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
8526 {
8527         u64 extra_flags = chunk_to_extended(flags) &
8528                                 BTRFS_EXTENDED_PROFILE_MASK;
8529
8530         write_seqlock(&fs_info->profiles_lock);
8531         if (flags & BTRFS_BLOCK_GROUP_DATA)
8532                 fs_info->avail_data_alloc_bits &= ~extra_flags;
8533         if (flags & BTRFS_BLOCK_GROUP_METADATA)
8534                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
8535         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
8536                 fs_info->avail_system_alloc_bits &= ~extra_flags;
8537         write_sequnlock(&fs_info->profiles_lock);
8538 }
8539
8540 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8541                              struct btrfs_root *root, u64 group_start)
8542 {
8543         struct btrfs_path *path;
8544         struct btrfs_block_group_cache *block_group;
8545         struct btrfs_free_cluster *cluster;
8546         struct btrfs_root *tree_root = root->fs_info->tree_root;
8547         struct btrfs_key key;
8548         struct inode *inode;
8549         int ret;
8550         int index;
8551         int factor;
8552
8553         root = root->fs_info->extent_root;
8554
8555         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8556         BUG_ON(!block_group);
8557         BUG_ON(!block_group->ro);
8558
8559         /*
8560          * Free the reserved super bytes from this block group before
8561          * remove it.
8562          */
8563         free_excluded_extents(root, block_group);
8564
8565         memcpy(&key, &block_group->key, sizeof(key));
8566         index = get_block_group_index(block_group);
8567         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
8568                                   BTRFS_BLOCK_GROUP_RAID1 |
8569                                   BTRFS_BLOCK_GROUP_RAID10))
8570                 factor = 2;
8571         else
8572                 factor = 1;
8573
8574         /* make sure this block group isn't part of an allocation cluster */
8575         cluster = &root->fs_info->data_alloc_cluster;
8576         spin_lock(&cluster->refill_lock);
8577         btrfs_return_cluster_to_free_space(block_group, cluster);
8578         spin_unlock(&cluster->refill_lock);
8579
8580         /*
8581          * make sure this block group isn't part of a metadata
8582          * allocation cluster
8583          */
8584         cluster = &root->fs_info->meta_alloc_cluster;
8585         spin_lock(&cluster->refill_lock);
8586         btrfs_return_cluster_to_free_space(block_group, cluster);
8587         spin_unlock(&cluster->refill_lock);
8588
8589         path = btrfs_alloc_path();
8590         if (!path) {
8591                 ret = -ENOMEM;
8592                 goto out;
8593         }
8594
8595         inode = lookup_free_space_inode(tree_root, block_group, path);
8596         if (!IS_ERR(inode)) {
8597                 ret = btrfs_orphan_add(trans, inode);
8598                 if (ret) {
8599                         btrfs_add_delayed_iput(inode);
8600                         goto out;
8601                 }
8602                 clear_nlink(inode);
8603                 /* One for the block groups ref */
8604                 spin_lock(&block_group->lock);
8605                 if (block_group->iref) {
8606                         block_group->iref = 0;
8607                         block_group->inode = NULL;
8608                         spin_unlock(&block_group->lock);
8609                         iput(inode);
8610                 } else {
8611                         spin_unlock(&block_group->lock);
8612                 }
8613                 /* One for our lookup ref */
8614                 btrfs_add_delayed_iput(inode);
8615         }
8616
8617         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8618         key.offset = block_group->key.objectid;
8619         key.type = 0;
8620
8621         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8622         if (ret < 0)
8623                 goto out;
8624         if (ret > 0)
8625                 btrfs_release_path(path);
8626         if (ret == 0) {
8627                 ret = btrfs_del_item(trans, tree_root, path);
8628                 if (ret)
8629                         goto out;
8630                 btrfs_release_path(path);
8631         }
8632
8633         spin_lock(&root->fs_info->block_group_cache_lock);
8634         rb_erase(&block_group->cache_node,
8635                  &root->fs_info->block_group_cache_tree);
8636
8637         if (root->fs_info->first_logical_byte == block_group->key.objectid)
8638                 root->fs_info->first_logical_byte = (u64)-1;
8639         spin_unlock(&root->fs_info->block_group_cache_lock);
8640
8641         down_write(&block_group->space_info->groups_sem);
8642         /*
8643          * we must use list_del_init so people can check to see if they
8644          * are still on the list after taking the semaphore
8645          */
8646         list_del_init(&block_group->list);
8647         if (list_empty(&block_group->space_info->block_groups[index]))
8648                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8649         up_write(&block_group->space_info->groups_sem);
8650
8651         if (block_group->cached == BTRFS_CACHE_STARTED)
8652                 wait_block_group_cache_done(block_group);
8653
8654         btrfs_remove_free_space_cache(block_group);
8655
8656         spin_lock(&block_group->space_info->lock);
8657         block_group->space_info->total_bytes -= block_group->key.offset;
8658         block_group->space_info->bytes_readonly -= block_group->key.offset;
8659         block_group->space_info->disk_total -= block_group->key.offset * factor;
8660         spin_unlock(&block_group->space_info->lock);
8661
8662         memcpy(&key, &block_group->key, sizeof(key));
8663
8664         btrfs_clear_space_info_full(root->fs_info);
8665
8666         btrfs_put_block_group(block_group);
8667         btrfs_put_block_group(block_group);
8668
8669         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8670         if (ret > 0)
8671                 ret = -EIO;
8672         if (ret < 0)
8673                 goto out;
8674
8675         ret = btrfs_del_item(trans, root, path);
8676 out:
8677         btrfs_free_path(path);
8678         return ret;
8679 }
8680
8681 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8682 {
8683         struct btrfs_space_info *space_info;
8684         struct btrfs_super_block *disk_super;
8685         u64 features;
8686         u64 flags;
8687         int mixed = 0;
8688         int ret;
8689
8690         disk_super = fs_info->super_copy;
8691         if (!btrfs_super_root(disk_super))
8692                 return 1;
8693
8694         features = btrfs_super_incompat_flags(disk_super);
8695         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8696                 mixed = 1;
8697
8698         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8699         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8700         if (ret)
8701                 goto out;
8702
8703         if (mixed) {
8704                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8705                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8706         } else {
8707                 flags = BTRFS_BLOCK_GROUP_METADATA;
8708                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8709                 if (ret)
8710                         goto out;
8711
8712                 flags = BTRFS_BLOCK_GROUP_DATA;
8713                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8714         }
8715 out:
8716         return ret;
8717 }
8718
8719 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8720 {
8721         return unpin_extent_range(root, start, end);
8722 }
8723
8724 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8725                                u64 num_bytes, u64 *actual_bytes)
8726 {
8727         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8728 }
8729
8730 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8731 {
8732         struct btrfs_fs_info *fs_info = root->fs_info;
8733         struct btrfs_block_group_cache *cache = NULL;
8734         u64 group_trimmed;
8735         u64 start;
8736         u64 end;
8737         u64 trimmed = 0;
8738         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8739         int ret = 0;
8740
8741         /*
8742          * try to trim all FS space, our block group may start from non-zero.
8743          */
8744         if (range->len == total_bytes)
8745                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8746         else
8747                 cache = btrfs_lookup_block_group(fs_info, range->start);
8748
8749         while (cache) {
8750                 if (cache->key.objectid >= (range->start + range->len)) {
8751                         btrfs_put_block_group(cache);
8752                         break;
8753                 }
8754
8755                 start = max(range->start, cache->key.objectid);
8756                 end = min(range->start + range->len,
8757                                 cache->key.objectid + cache->key.offset);
8758
8759                 if (end - start >= range->minlen) {
8760                         if (!block_group_cache_done(cache)) {
8761                                 ret = cache_block_group(cache, 0);
8762                                 if (ret) {
8763                                         btrfs_put_block_group(cache);
8764                                         break;
8765                                 }
8766                                 ret = wait_block_group_cache_done(cache);
8767                                 if (ret) {
8768                                         btrfs_put_block_group(cache);
8769                                         break;
8770                                 }
8771                         }
8772                         ret = btrfs_trim_block_group(cache,
8773                                                      &group_trimmed,
8774                                                      start,
8775                                                      end,
8776                                                      range->minlen);
8777
8778                         trimmed += group_trimmed;
8779                         if (ret) {
8780                                 btrfs_put_block_group(cache);
8781                                 break;
8782                         }
8783                 }
8784
8785                 cache = next_block_group(fs_info->tree_root, cache);
8786         }
8787
8788         range->len = trimmed;
8789         return ret;
8790 }