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 "hash.h"
  29 #include "tree-log.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "volumes.h"
  33 #include "raid56.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36 #include "free-space-tree.h"
  37 #include "math.h"
  38 #include "sysfs.h"
  39 #include "qgroup.h"
  40
  41 #undef SCRAMBLE_DELAYED_REFS
  42
  43 /*
  44  * control flags for do_chunk_alloc's force field
  45  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  46  * if we really need one.
  47  *
  48  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  49  * if we have very few chunks already allocated.  This is
  50  * used as part of the clustering code to help make sure
  51  * we have a good pool of storage to cluster in, without
  52  * filling the FS with empty chunks
  53  *
  54  * CHUNK_ALLOC_FORCE means it must try to allocate one
  55  *
  56  */
  57 enum {
  58         CHUNK_ALLOC_NO_FORCE = 0,
  59         CHUNK_ALLOC_LIMITED = 1,
  60         CHUNK_ALLOC_FORCE = 2,
  61 };
  62
  63 /*
  64  * Control how reservations are dealt with.
  65  *
  66  * RESERVE_FREE - freeing a reservation.
  67  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  68  *   ENOSPC accounting
  69  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  70  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  71  */
  72 enum {
  73         RESERVE_FREE = 0,
  74         RESERVE_ALLOC = 1,
  75         RESERVE_ALLOC_NO_ACCOUNT = 2,
  76 };
  77
  78 static int update_block_group(struct btrfs_trans_handle *trans,
  79                               struct btrfs_root *root, u64 bytenr,
  80                               u64 num_bytes, int alloc);
  81 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  82                                 struct btrfs_root *root,
  83                                 struct btrfs_delayed_ref_node *node, u64 parent,
  84                                 u64 root_objectid, u64 owner_objectid,
  85                                 u64 owner_offset, int refs_to_drop,
  86                                 struct btrfs_delayed_extent_op *extra_op);
  87 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  88                                     struct extent_buffer *leaf,
  89                                     struct btrfs_extent_item *ei);
  90 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  91                                       struct btrfs_root *root,
  92                                       u64 parent, u64 root_objectid,
  93                                       u64 flags, u64 owner, u64 offset,
  94                                       struct btrfs_key *ins, int ref_mod);
  95 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  96                                      struct btrfs_root *root,
  97                                      u64 parent, u64 root_objectid,
  98                                      u64 flags, struct btrfs_disk_key *key,
  99                                      int level, struct btrfs_key *ins);
 100 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 101                           struct btrfs_root *extent_root, u64 flags,
 102                           int force);
 103 static int find_next_key(struct btrfs_path *path, int level,
 104                          struct btrfs_key *key);
 105 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 106                             int dump_block_groups);
 107 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 108                                        u64 num_bytes, int reserve,
 109                                        int delalloc);
 110 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 111                                u64 num_bytes);
 112 int btrfs_pin_extent(struct btrfs_root *root,
 113                      u64 bytenr, u64 num_bytes, int reserved);
 114
 115 static noinline int
 116 block_group_cache_done(struct btrfs_block_group_cache *cache)
 117 {
 118         smp_mb();
 119         return cache->cached == BTRFS_CACHE_FINISHED ||
 120                 cache->cached == BTRFS_CACHE_ERROR;
 121 }
 122
 123 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 124 {
 125         return (cache->flags & bits) == bits;
 126 }
 127
 128 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 129 {
 130         atomic_inc(&cache->count);
 131 }
 132
 133 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 134 {
 135         if (atomic_dec_and_test(&cache->count)) {
 136                 WARN_ON(cache->pinned > 0);
 137                 WARN_ON(cache->reserved > 0);
 138                 kfree(cache->free_space_ctl);
 139                 kfree(cache);
 140         }
 141 }
 142
 143 /*
 144  * this adds the block group to the fs_info rb tree for the block group
 145  * cache
 146  */
 147 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 148                                 struct btrfs_block_group_cache *block_group)
 149 {
 150         struct rb_node **p;
 151         struct rb_node *parent = NULL;
 152         struct btrfs_block_group_cache *cache;
 153
 154         spin_lock(&info->block_group_cache_lock);
 155         p = &info->block_group_cache_tree.rb_node;
 156
 157         while (*p) {
 158                 parent = *p;
 159                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 160                                  cache_node);
 161                 if (block_group->key.objectid < cache->key.objectid) {
 162                         p = &(*p)->rb_left;
 163                 } else if (block_group->key.objectid > cache->key.objectid) {
 164                         p = &(*p)->rb_right;
 165                 } else {
 166                         spin_unlock(&info->block_group_cache_lock);
 167                         return -EEXIST;
 168                 }
 169         }
 170
 171         rb_link_node(&block_group->cache_node, parent, p);
 172         rb_insert_color(&block_group->cache_node,
 173                         &info->block_group_cache_tree);
 174
 175         if (info->first_logical_byte > block_group->key.objectid)
 176                 info->first_logical_byte = block_group->key.objectid;
 177
 178         spin_unlock(&info->block_group_cache_lock);
 179
 180         return 0;
 181 }
 182
 183 /*
 184  * This will return the block group at or after bytenr if contains is 0, else
 185  * it will return the block group that contains the bytenr
 186  */
 187 static struct btrfs_block_group_cache *
 188 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 189                               int contains)
 190 {
 191         struct btrfs_block_group_cache *cache, *ret = NULL;
 192         struct rb_node *n;
 193         u64 end, start;
 194
 195         spin_lock(&info->block_group_cache_lock);
 196         n = info->block_group_cache_tree.rb_node;
 197
 198         while (n) {
 199                 cache = rb_entry(n, struct btrfs_block_group_cache,
 200                                  cache_node);
 201                 end = cache->key.objectid + cache->key.offset - 1;
 202                 start = cache->key.objectid;
 203
 204                 if (bytenr < start) {
 205                         if (!contains && (!ret || start < ret->key.objectid))
 206                                 ret = cache;
 207                         n = n->rb_left;
 208                 } else if (bytenr > start) {
 209                         if (contains && bytenr <= end) {
 210                                 ret = cache;
 211                                 break;
 212                         }
 213                         n = n->rb_right;
 214                 } else {
 215                         ret = cache;
 216                         break;
 217                 }
 218         }
 219         if (ret) {
 220                 btrfs_get_block_group(ret);
 221                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 222                         info->first_logical_byte = ret->key.objectid;
 223         }
 224         spin_unlock(&info->block_group_cache_lock);
 225
 226         return ret;
 227 }
 228
 229 static int add_excluded_extent(struct btrfs_root *root,
 230                                u64 start, u64 num_bytes)
 231 {
 232         u64 end = start + num_bytes - 1;
 233         set_extent_bits(&root->fs_info->freed_extents[0],
 234                         start, end, EXTENT_UPTODATE);
 235         set_extent_bits(&root->fs_info->freed_extents[1],
 236                         start, end, EXTENT_UPTODATE);
 237         return 0;
 238 }
 239
 240 static void free_excluded_extents(struct btrfs_root *root,
 241                                   struct btrfs_block_group_cache *cache)
 242 {
 243         u64 start, end;
 244
 245         start = cache->key.objectid;
 246         end = start + cache->key.offset - 1;
 247
 248         clear_extent_bits(&root->fs_info->freed_extents[0],
 249                           start, end, EXTENT_UPTODATE);
 250         clear_extent_bits(&root->fs_info->freed_extents[1],
 251                           start, end, EXTENT_UPTODATE);
 252 }
 253
 254 static int exclude_super_stripes(struct btrfs_root *root,
 255                                  struct btrfs_block_group_cache *cache)
 256 {
 257         u64 bytenr;
 258         u64 *logical;
 259         int stripe_len;
 260         int i, nr, ret;
 261
 262         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 263                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 264                 cache->bytes_super += stripe_len;
 265                 ret = add_excluded_extent(root, cache->key.objectid,
 266                                           stripe_len);
 267                 if (ret)
 268                         return ret;
 269         }
 270
 271         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 272                 bytenr = btrfs_sb_offset(i);
 273                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 274                                        cache->key.objectid, bytenr,
 275                                        0, &logical, &nr, &stripe_len);
 276                 if (ret)
 277                         return ret;
 278
 279                 while (nr--) {
 280                         u64 start, len;
 281
 282                         if (logical[nr] > cache->key.objectid +
 283                             cache->key.offset)
 284                                 continue;
 285
 286                         if (logical[nr] + stripe_len <= cache->key.objectid)
 287                                 continue;
 288
 289                         start = logical[nr];
 290                         if (start < cache->key.objectid) {
 291                                 start = cache->key.objectid;
 292                                 len = (logical[nr] + stripe_len) - start;
 293                         } else {
 294                                 len = min_t(u64, stripe_len,
 295                                             cache->key.objectid +
 296                                             cache->key.offset - start);
 297                         }
 298
 299                         cache->bytes_super += len;
 300                         ret = add_excluded_extent(root, start, len);
 301                         if (ret) {
 302                                 kfree(logical);
 303                                 return ret;
 304                         }
 305                 }
 306
 307                 kfree(logical);
 308         }
 309         return 0;
 310 }
 311
 312 static struct btrfs_caching_control *
 313 get_caching_control(struct btrfs_block_group_cache *cache)
 314 {
 315         struct btrfs_caching_control *ctl;
 316
 317         spin_lock(&cache->lock);
 318         if (!cache->caching_ctl) {
 319                 spin_unlock(&cache->lock);
 320                 return NULL;
 321         }
 322
 323         ctl = cache->caching_ctl;
 324         atomic_inc(&ctl->count);
 325         spin_unlock(&cache->lock);
 326         return ctl;
 327 }
 328
 329 static void put_caching_control(struct btrfs_caching_control *ctl)
 330 {
 331         if (atomic_dec_and_test(&ctl->count))
 332                 kfree(ctl);
 333 }
 334
 335 #ifdef CONFIG_BTRFS_DEBUG
 336 static void fragment_free_space(struct btrfs_root *root,
 337                                 struct btrfs_block_group_cache *block_group)
 338 {
 339         u64 start = block_group->key.objectid;
 340         u64 len = block_group->key.offset;
 341         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 342                 root->nodesize : root->sectorsize;
 343         u64 step = chunk << 1;
 344
 345         while (len > chunk) {
 346                 btrfs_remove_free_space(block_group, start, chunk);
 347                 start += step;
 348                 if (len < step)
 349                         len = 0;
 350                 else
 351                         len -= step;
 352         }
 353 }
 354 #endif
 355
 356 /*
 357  * this is only called by cache_block_group, since we could have freed extents
 358  * we need to check the pinned_extents for any extents that can't be used yet
 359  * since their free space will be released as soon as the transaction commits.
 360  */
 361 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 362                        struct btrfs_fs_info *info, u64 start, u64 end)
 363 {
 364         u64 extent_start, extent_end, size, total_added = 0;
 365         int ret;
 366
 367         while (start < end) {
 368                 ret = find_first_extent_bit(info->pinned_extents, start,
 369                                             &extent_start, &extent_end,
 370                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 371                                             NULL);
 372                 if (ret)
 373                         break;
 374
 375                 if (extent_start <= start) {
 376                         start = extent_end + 1;
 377                 } else if (extent_start > start && extent_start < end) {
 378                         size = extent_start - start;
 379                         total_added += size;
 380                         ret = btrfs_add_free_space(block_group, start,
 381                                                    size);
 382                         BUG_ON(ret); /* -ENOMEM or logic error */
 383                         start = extent_end + 1;
 384                 } else {
 385                         break;
 386                 }
 387         }
 388
 389         if (start < end) {
 390                 size = end - start;
 391                 total_added += size;
 392                 ret = btrfs_add_free_space(block_group, start, size);
 393                 BUG_ON(ret); /* -ENOMEM or logic error */
 394         }
 395
 396         return total_added;
 397 }
 398
 399 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 400 {
 401         struct btrfs_block_group_cache *block_group;
 402         struct btrfs_fs_info *fs_info;
 403         struct btrfs_root *extent_root;
 404         struct btrfs_path *path;
 405         struct extent_buffer *leaf;
 406         struct btrfs_key key;
 407         u64 total_found = 0;
 408         u64 last = 0;
 409         u32 nritems;
 410         int ret;
 411         bool wakeup = true;
 412
 413         block_group = caching_ctl->block_group;
 414         fs_info = block_group->fs_info;
 415         extent_root = fs_info->extent_root;
 416
 417         path = btrfs_alloc_path();
 418         if (!path)
 419                 return -ENOMEM;
 420
 421         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 422
 423 #ifdef CONFIG_BTRFS_DEBUG
 424         /*
 425          * If we're fragmenting we don't want to make anybody think we can
 426          * allocate from this block group until we've had a chance to fragment
 427          * the free space.
 428          */
 429         if (btrfs_should_fragment_free_space(extent_root, block_group))
 430                 wakeup = false;
 431 #endif
 432         /*
 433          * We don't want to deadlock with somebody trying to allocate a new
 434          * extent for the extent root while also trying to search the extent
 435          * root to add free space.  So we skip locking and search the commit
 436          * root, since its read-only
 437          */
 438         path->skip_locking = 1;
 439         path->search_commit_root = 1;
 440         path->reada = READA_FORWARD;
 441
 442         key.objectid = last;
 443         key.offset = 0;
 444         key.type = BTRFS_EXTENT_ITEM_KEY;
 445
 446 next:
 447         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 448         if (ret < 0)
 449                 goto out;
 450
 451         leaf = path->nodes[0];
 452         nritems = btrfs_header_nritems(leaf);
 453
 454         while (1) {
 455                 if (btrfs_fs_closing(fs_info) > 1) {
 456                         last = (u64)-1;
 457                         break;
 458                 }
 459
 460                 if (path->slots[0] < nritems) {
 461                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 462                 } else {
 463                         ret = find_next_key(path, 0, &key);
 464                         if (ret)
 465                                 break;
 466
 467                         if (need_resched() ||
 468                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 469                                 if (wakeup)
 470                                         caching_ctl->progress = last;
 471                                 btrfs_release_path(path);
 472                                 up_read(&fs_info->commit_root_sem);
 473                                 mutex_unlock(&caching_ctl->mutex);
 474                                 cond_resched();
 475                                 mutex_lock(&caching_ctl->mutex);
 476                                 down_read(&fs_info->commit_root_sem);
 477                                 goto next;
 478                         }
 479
 480                         ret = btrfs_next_leaf(extent_root, path);
 481                         if (ret < 0)
 482                                 goto out;
 483                         if (ret)
 484                                 break;
 485                         leaf = path->nodes[0];
 486                         nritems = btrfs_header_nritems(leaf);
 487                         continue;
 488                 }
 489
 490                 if (key.objectid < last) {
 491                         key.objectid = last;
 492                         key.offset = 0;
 493                         key.type = BTRFS_EXTENT_ITEM_KEY;
 494
 495                         if (wakeup)
 496                                 caching_ctl->progress = last;
 497                         btrfs_release_path(path);
 498                         goto next;
 499                 }
 500
 501                 if (key.objectid < block_group->key.objectid) {
 502                         path->slots[0]++;
 503                         continue;
 504                 }
 505
 506                 if (key.objectid >= block_group->key.objectid +
 507                     block_group->key.offset)
 508                         break;
 509
 510                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 511                     key.type == BTRFS_METADATA_ITEM_KEY) {
 512                         total_found += add_new_free_space(block_group,
 513                                                           fs_info, last,
 514                                                           key.objectid);
 515                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 516                                 last = key.objectid +
 517                                         fs_info->tree_root->nodesize;
 518                         else
 519                                 last = key.objectid + key.offset;
 520
 521                         if (total_found > CACHING_CTL_WAKE_UP) {
 522                                 total_found = 0;
 523                                 if (wakeup)
 524                                         wake_up(&caching_ctl->wait);
 525                         }
 526                 }
 527                 path->slots[0]++;
 528         }
 529         ret = 0;
 530
 531         total_found += add_new_free_space(block_group, fs_info, last,
 532                                           block_group->key.objectid +
 533                                           block_group->key.offset);
 534         caching_ctl->progress = (u64)-1;
 535
 536 out:
 537         btrfs_free_path(path);
 538         return ret;
 539 }
 540
 541 static noinline void caching_thread(struct btrfs_work *work)
 542 {
 543         struct btrfs_block_group_cache *block_group;
 544         struct btrfs_fs_info *fs_info;
 545         struct btrfs_caching_control *caching_ctl;
 546         struct btrfs_root *extent_root;
 547         int ret;
 548
 549         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 550         block_group = caching_ctl->block_group;
 551         fs_info = block_group->fs_info;
 552         extent_root = fs_info->extent_root;
 553
 554         mutex_lock(&caching_ctl->mutex);
 555         down_read(&fs_info->commit_root_sem);
 556
 557         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 558                 ret = load_free_space_tree(caching_ctl);
 559         else
 560                 ret = load_extent_tree_free(caching_ctl);
 561
 562         spin_lock(&block_group->lock);
 563         block_group->caching_ctl = NULL;
 564         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 565         spin_unlock(&block_group->lock);
 566
 567 #ifdef CONFIG_BTRFS_DEBUG
 568         if (btrfs_should_fragment_free_space(extent_root, block_group)) {
 569                 u64 bytes_used;
 570
 571                 spin_lock(&block_group->space_info->lock);
 572                 spin_lock(&block_group->lock);
 573                 bytes_used = block_group->key.offset -
 574                         btrfs_block_group_used(&block_group->item);
 575                 block_group->space_info->bytes_used += bytes_used >> 1;
 576                 spin_unlock(&block_group->lock);
 577                 spin_unlock(&block_group->space_info->lock);
 578                 fragment_free_space(extent_root, block_group);
 579         }
 580 #endif
 581
 582         caching_ctl->progress = (u64)-1;
 583
 584         up_read(&fs_info->commit_root_sem);
 585         free_excluded_extents(fs_info->extent_root, block_group);
 586         mutex_unlock(&caching_ctl->mutex);
 587
 588         wake_up(&caching_ctl->wait);
 589
 590         put_caching_control(caching_ctl);
 591         btrfs_put_block_group(block_group);
 592 }
 593
 594 static int cache_block_group(struct btrfs_block_group_cache *cache,
 595                              int load_cache_only)
 596 {
 597         DEFINE_WAIT(wait);
 598         struct btrfs_fs_info *fs_info = cache->fs_info;
 599         struct btrfs_caching_control *caching_ctl;
 600         int ret = 0;
 601
 602         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 603         if (!caching_ctl)
 604                 return -ENOMEM;
 605
 606         INIT_LIST_HEAD(&caching_ctl->list);
 607         mutex_init(&caching_ctl->mutex);
 608         init_waitqueue_head(&caching_ctl->wait);
 609         caching_ctl->block_group = cache;
 610         caching_ctl->progress = cache->key.objectid;
 611         atomic_set(&caching_ctl->count, 1);
 612         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 613                         caching_thread, NULL, NULL);
 614
 615         spin_lock(&cache->lock);
 616         /*
 617          * This should be a rare occasion, but this could happen I think in the
 618          * case where one thread starts to load the space cache info, and then
 619          * some other thread starts a transaction commit which tries to do an
 620          * allocation while the other thread is still loading the space cache
 621          * info.  The previous loop should have kept us from choosing this block
 622          * group, but if we've moved to the state where we will wait on caching
 623          * block groups we need to first check if we're doing a fast load here,
 624          * so we can wait for it to finish, otherwise we could end up allocating
 625          * from a block group who's cache gets evicted for one reason or
 626          * another.
 627          */
 628         while (cache->cached == BTRFS_CACHE_FAST) {
 629                 struct btrfs_caching_control *ctl;
 630
 631                 ctl = cache->caching_ctl;
 632                 atomic_inc(&ctl->count);
 633                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 634                 spin_unlock(&cache->lock);
 635
 636                 schedule();
 637
 638                 finish_wait(&ctl->wait, &wait);
 639                 put_caching_control(ctl);
 640                 spin_lock(&cache->lock);
 641         }
 642
 643         if (cache->cached != BTRFS_CACHE_NO) {
 644                 spin_unlock(&cache->lock);
 645                 kfree(caching_ctl);
 646                 return 0;
 647         }
 648         WARN_ON(cache->caching_ctl);
 649         cache->caching_ctl = caching_ctl;
 650         cache->cached = BTRFS_CACHE_FAST;
 651         spin_unlock(&cache->lock);
 652
 653         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 654                 mutex_lock(&caching_ctl->mutex);
 655                 ret = load_free_space_cache(fs_info, cache);
 656
 657                 spin_lock(&cache->lock);
 658                 if (ret == 1) {
 659                         cache->caching_ctl = NULL;
 660                         cache->cached = BTRFS_CACHE_FINISHED;
 661                         cache->last_byte_to_unpin = (u64)-1;
 662                         caching_ctl->progress = (u64)-1;
 663                 } else {
 664                         if (load_cache_only) {
 665                                 cache->caching_ctl = NULL;
 666                                 cache->cached = BTRFS_CACHE_NO;
 667                         } else {
 668                                 cache->cached = BTRFS_CACHE_STARTED;
 669                                 cache->has_caching_ctl = 1;
 670                         }
 671                 }
 672                 spin_unlock(&cache->lock);
 673 #ifdef CONFIG_BTRFS_DEBUG
 674                 if (ret == 1 &&
 675                     btrfs_should_fragment_free_space(fs_info->extent_root,
 676                                                      cache)) {
 677                         u64 bytes_used;
 678
 679                         spin_lock(&cache->space_info->lock);
 680                         spin_lock(&cache->lock);
 681                         bytes_used = cache->key.offset -
 682                                 btrfs_block_group_used(&cache->item);
 683                         cache->space_info->bytes_used += bytes_used >> 1;
 684                         spin_unlock(&cache->lock);
 685                         spin_unlock(&cache->space_info->lock);
 686                         fragment_free_space(fs_info->extent_root, cache);
 687                 }
 688 #endif
 689                 mutex_unlock(&caching_ctl->mutex);
 690
 691                 wake_up(&caching_ctl->wait);
 692                 if (ret == 1) {
 693                         put_caching_control(caching_ctl);
 694                         free_excluded_extents(fs_info->extent_root, cache);
 695                         return 0;
 696                 }
 697         } else {
 698                 /*
 699                  * We're either using the free space tree or no caching at all.
 700                  * Set cached to the appropriate value and wakeup any waiters.
 701                  */
 702                 spin_lock(&cache->lock);
 703                 if (load_cache_only) {
 704                         cache->caching_ctl = NULL;
 705                         cache->cached = BTRFS_CACHE_NO;
 706                 } else {
 707                         cache->cached = BTRFS_CACHE_STARTED;
 708                         cache->has_caching_ctl = 1;
 709                 }
 710                 spin_unlock(&cache->lock);
 711                 wake_up(&caching_ctl->wait);
 712         }
 713
 714         if (load_cache_only) {
 715                 put_caching_control(caching_ctl);
 716                 return 0;
 717         }
 718
 719         down_write(&fs_info->commit_root_sem);
 720         atomic_inc(&caching_ctl->count);
 721         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 722         up_write(&fs_info->commit_root_sem);
 723
 724         btrfs_get_block_group(cache);
 725
 726         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 727
 728         return ret;
 729 }
 730
 731 /*
 732  * return the block group that starts at or after bytenr
 733  */
 734 static struct btrfs_block_group_cache *
 735 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 736 {
 737         struct btrfs_block_group_cache *cache;
 738
 739         cache = block_group_cache_tree_search(info, bytenr, 0);
 740
 741         return cache;
 742 }
 743
 744 /*
 745  * return the block group that contains the given bytenr
 746  */
 747 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 748                                                  struct btrfs_fs_info *info,
 749                                                  u64 bytenr)
 750 {
 751         struct btrfs_block_group_cache *cache;
 752
 753         cache = block_group_cache_tree_search(info, bytenr, 1);
 754
 755         return cache;
 756 }
 757
 758 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 759                                                   u64 flags)
 760 {
 761         struct list_head *head = &info->space_info;
 762         struct btrfs_space_info *found;
 763
 764         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 765
 766         rcu_read_lock();
 767         list_for_each_entry_rcu(found, head, list) {
 768                 if (found->flags & flags) {
 769                         rcu_read_unlock();
 770                         return found;
 771                 }
 772         }
 773         rcu_read_unlock();
 774         return NULL;
 775 }
 776
 777 /*
 778  * after adding space to the filesystem, we need to clear the full flags
 779  * on all the space infos.
 780  */
 781 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 782 {
 783         struct list_head *head = &info->space_info;
 784         struct btrfs_space_info *found;
 785
 786         rcu_read_lock();
 787         list_for_each_entry_rcu(found, head, list)
 788                 found->full = 0;
 789         rcu_read_unlock();
 790 }
 791
 792 /* simple helper to search for an existing data extent at a given offset */
 793 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
 794 {
 795         int ret;
 796         struct btrfs_key key;
 797         struct btrfs_path *path;
 798
 799         path = btrfs_alloc_path();
 800         if (!path)
 801                 return -ENOMEM;
 802
 803         key.objectid = start;
 804         key.offset = len;
 805         key.type = BTRFS_EXTENT_ITEM_KEY;
 806         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 807                                 0, 0);
 808         btrfs_free_path(path);
 809         return ret;
 810 }
 811
 812 /*
 813  * helper function to lookup reference count and flags of a tree block.
 814  *
 815  * the head node for delayed ref is used to store the sum of all the
 816  * reference count modifications queued up in the rbtree. the head
 817  * node may also store the extent flags to set. This way you can check
 818  * to see what the reference count and extent flags would be if all of
 819  * the delayed refs are not processed.
 820  */
 821 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 822                              struct btrfs_root *root, u64 bytenr,
 823                              u64 offset, int metadata, u64 *refs, u64 *flags)
 824 {
 825         struct btrfs_delayed_ref_head *head;
 826         struct btrfs_delayed_ref_root *delayed_refs;
 827         struct btrfs_path *path;
 828         struct btrfs_extent_item *ei;
 829         struct extent_buffer *leaf;
 830         struct btrfs_key key;
 831         u32 item_size;
 832         u64 num_refs;
 833         u64 extent_flags;
 834         int ret;
 835
 836         /*
 837          * If we don't have skinny metadata, don't bother doing anything
 838          * different
 839          */
 840         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 841                 offset = root->nodesize;
 842                 metadata = 0;
 843         }
 844
 845         path = btrfs_alloc_path();
 846         if (!path)
 847                 return -ENOMEM;
 848
 849         if (!trans) {
 850                 path->skip_locking = 1;
 851                 path->search_commit_root = 1;
 852         }
 853
 854 search_again:
 855         key.objectid = bytenr;
 856         key.offset = offset;
 857         if (metadata)
 858                 key.type = BTRFS_METADATA_ITEM_KEY;
 859         else
 860                 key.type = BTRFS_EXTENT_ITEM_KEY;
 861
 862         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 863                                 &key, path, 0, 0);
 864         if (ret < 0)
 865                 goto out_free;
 866
 867         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 868                 if (path->slots[0]) {
 869                         path->slots[0]--;
 870                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 871                                               path->slots[0]);
 872                         if (key.objectid == bytenr &&
 873                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 874                             key.offset == root->nodesize)
 875                                 ret = 0;
 876                 }
 877         }
 878
 879         if (ret == 0) {
 880                 leaf = path->nodes[0];
 881                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 882                 if (item_size >= sizeof(*ei)) {
 883                         ei = btrfs_item_ptr(leaf, path->slots[0],
 884                                             struct btrfs_extent_item);
 885                         num_refs = btrfs_extent_refs(leaf, ei);
 886                         extent_flags = btrfs_extent_flags(leaf, ei);
 887                 } else {
 888 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 889                         struct btrfs_extent_item_v0 *ei0;
 890                         BUG_ON(item_size != sizeof(*ei0));
 891                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 892                                              struct btrfs_extent_item_v0);
 893                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 894                         /* FIXME: this isn't correct for data */
 895                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 896 #else
 897                         BUG();
 898 #endif
 899                 }
 900                 BUG_ON(num_refs == 0);
 901         } else {
 902                 num_refs = 0;
 903                 extent_flags = 0;
 904                 ret = 0;
 905         }
 906
 907         if (!trans)
 908                 goto out;
 909
 910         delayed_refs = &trans->transaction->delayed_refs;
 911         spin_lock(&delayed_refs->lock);
 912         head = btrfs_find_delayed_ref_head(trans, bytenr);
 913         if (head) {
 914                 if (!mutex_trylock(&head->mutex)) {
 915                         atomic_inc(&head->node.refs);
 916                         spin_unlock(&delayed_refs->lock);
 917
 918                         btrfs_release_path(path);
 919
 920                         /*
 921                          * Mutex was contended, block until it's released and try
 922                          * again
 923                          */
 924                         mutex_lock(&head->mutex);
 925                         mutex_unlock(&head->mutex);
 926                         btrfs_put_delayed_ref(&head->node);
 927                         goto search_again;
 928                 }
 929                 spin_lock(&head->lock);
 930                 if (head->extent_op && head->extent_op->update_flags)
 931                         extent_flags |= head->extent_op->flags_to_set;
 932                 else
 933                         BUG_ON(num_refs == 0);
 934
 935                 num_refs += head->node.ref_mod;
 936                 spin_unlock(&head->lock);
 937                 mutex_unlock(&head->mutex);
 938         }
 939         spin_unlock(&delayed_refs->lock);
 940 out:
 941         WARN_ON(num_refs == 0);
 942         if (refs)
 943                 *refs = num_refs;
 944         if (flags)
 945                 *flags = extent_flags;
 946 out_free:
 947         btrfs_free_path(path);
 948         return ret;
 949 }
 950
 951 /*
 952  * Back reference rules.  Back refs have three main goals:
 953  *
 954  * 1) differentiate between all holders of references to an extent so that
 955  *    when a reference is dropped we can make sure it was a valid reference
 956  *    before freeing the extent.
 957  *
 958  * 2) Provide enough information to quickly find the holders of an extent
 959  *    if we notice a given block is corrupted or bad.
 960  *
 961  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 962  *    maintenance.  This is actually the same as #2, but with a slightly
 963  *    different use case.
 964  *
 965  * There are two kinds of back refs. The implicit back refs is optimized
 966  * for pointers in non-shared tree blocks. For a given pointer in a block,
 967  * back refs of this kind provide information about the block's owner tree
 968  * and the pointer's key. These information allow us to find the block by
 969  * b-tree searching. The full back refs is for pointers in tree blocks not
 970  * referenced by their owner trees. The location of tree block is recorded
 971  * in the back refs. Actually the full back refs is generic, and can be
 972  * used in all cases the implicit back refs is used. The major shortcoming
 973  * of the full back refs is its overhead. Every time a tree block gets
 974  * COWed, we have to update back refs entry for all pointers in it.
 975  *
 976  * For a newly allocated tree block, we use implicit back refs for
 977  * pointers in it. This means most tree related operations only involve
 978  * implicit back refs. For a tree block created in old transaction, the
 979  * only way to drop a reference to it is COW it. So we can detect the
 980  * event that tree block loses its owner tree's reference and do the
 981  * back refs conversion.
 982  *
 983  * When a tree block is COWed through a tree, there are four cases:
 984  *
 985  * The reference count of the block is one and the tree is the block's
 986  * owner tree. Nothing to do in this case.
 987  *
 988  * The reference count of the block is one and the tree is not the
 989  * block's owner tree. In this case, full back refs is used for pointers
 990  * in the block. Remove these full back refs, add implicit back refs for
 991  * every pointers in the new block.
 992  *
 993  * The reference count of the block is greater than one and the tree is
 994  * the block's owner tree. In this case, implicit back refs is used for
 995  * pointers in the block. Add full back refs for every pointers in the
 996  * block, increase lower level extents' reference counts. The original
 997  * implicit back refs are entailed to the new block.
 998  *
 999  * The reference count of the block is greater than one and the tree is
1000  * not the block's owner tree. Add implicit back refs for every pointer in
1001  * the new block, increase lower level extents' reference count.
1002  *
1003  * Back Reference Key composing:
1004  *
1005  * The key objectid corresponds to the first byte in the extent,
1006  * The key type is used to differentiate between types of back refs.
1007  * There are different meanings of the key offset for different types
1008  * of back refs.
1009  *
1010  * File extents can be referenced by:
1011  *
1012  * - multiple snapshots, subvolumes, or different generations in one subvol
1013  * - different files inside a single subvolume
1014  * - different offsets inside a file (bookend extents in file.c)
1015  *
1016  * The extent ref structure for the implicit back refs has fields for:
1017  *
1018  * - Objectid of the subvolume root
1019  * - objectid of the file holding the reference
1020  * - original offset in the file
1021  * - how many bookend extents
1022  *
1023  * The key offset for the implicit back refs is hash of the first
1024  * three fields.
1025  *
1026  * The extent ref structure for the full back refs has field for:
1027  *
1028  * - number of pointers in the tree leaf
1029  *
1030  * The key offset for the implicit back refs is the first byte of
1031  * the tree leaf
1032  *
1033  * When a file extent is allocated, The implicit back refs is used.
1034  * the fields are filled in:
1035  *
1036  *     (root_key.objectid, inode objectid, offset in file, 1)
1037  *
1038  * When a file extent is removed file truncation, we find the
1039  * corresponding implicit back refs and check the following fields:
1040  *
1041  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1042  *
1043  * Btree extents can be referenced by:
1044  *
1045  * - Different subvolumes
1046  *
1047  * Both the implicit back refs and the full back refs for tree blocks
1048  * only consist of key. The key offset for the implicit back refs is
1049  * objectid of block's owner tree. The key offset for the full back refs
1050  * is the first byte of parent block.
1051  *
1052  * When implicit back refs is used, information about the lowest key and
1053  * level of the tree block are required. These information are stored in
1054  * tree block info structure.
1055  */
1056
1057 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1058 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1059                                   struct btrfs_root *root,
1060                                   struct btrfs_path *path,
1061                                   u64 owner, u32 extra_size)
1062 {
1063         struct btrfs_extent_item *item;
1064         struct btrfs_extent_item_v0 *ei0;
1065         struct btrfs_extent_ref_v0 *ref0;
1066         struct btrfs_tree_block_info *bi;
1067         struct extent_buffer *leaf;
1068         struct btrfs_key key;
1069         struct btrfs_key found_key;
1070         u32 new_size = sizeof(*item);
1071         u64 refs;
1072         int ret;
1073
1074         leaf = path->nodes[0];
1075         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1076
1077         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1078         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1079                              struct btrfs_extent_item_v0);
1080         refs = btrfs_extent_refs_v0(leaf, ei0);
1081
1082         if (owner == (u64)-1) {
1083                 while (1) {
1084                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1085                                 ret = btrfs_next_leaf(root, path);
1086                                 if (ret < 0)
1087                                         return ret;
1088                                 BUG_ON(ret > 0); /* Corruption */
1089                                 leaf = path->nodes[0];
1090                         }
1091                         btrfs_item_key_to_cpu(leaf, &found_key,
1092                                               path->slots[0]);
1093                         BUG_ON(key.objectid != found_key.objectid);
1094                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1095                                 path->slots[0]++;
1096                                 continue;
1097                         }
1098                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1099                                               struct btrfs_extent_ref_v0);
1100                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1101                         break;
1102                 }
1103         }
1104         btrfs_release_path(path);
1105
1106         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1107                 new_size += sizeof(*bi);
1108
1109         new_size -= sizeof(*ei0);
1110         ret = btrfs_search_slot(trans, root, &key, path,
1111                                 new_size + extra_size, 1);
1112         if (ret < 0)
1113                 return ret;
1114         BUG_ON(ret); /* Corruption */
1115
1116         btrfs_extend_item(root, path, new_size);
1117
1118         leaf = path->nodes[0];
1119         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1120         btrfs_set_extent_refs(leaf, item, refs);
1121         /* FIXME: get real generation */
1122         btrfs_set_extent_generation(leaf, item, 0);
1123         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1124                 btrfs_set_extent_flags(leaf, item,
1125                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1126                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1127                 bi = (struct btrfs_tree_block_info *)(item + 1);
1128                 /* FIXME: get first key of the block */
1129                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1130                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1131         } else {
1132                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1133         }
1134         btrfs_mark_buffer_dirty(leaf);
1135         return 0;
1136 }
1137 #endif
1138
1139 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1140 {
1141         u32 high_crc = ~(u32)0;
1142         u32 low_crc = ~(u32)0;
1143         __le64 lenum;
1144
1145         lenum = cpu_to_le64(root_objectid);
1146         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1147         lenum = cpu_to_le64(owner);
1148         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1149         lenum = cpu_to_le64(offset);
1150         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1151
1152         return ((u64)high_crc << 31) ^ (u64)low_crc;
1153 }
1154
1155 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1156                                      struct btrfs_extent_data_ref *ref)
1157 {
1158         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1159                                     btrfs_extent_data_ref_objectid(leaf, ref),
1160                                     btrfs_extent_data_ref_offset(leaf, ref));
1161 }
1162
1163 static int match_extent_data_ref(struct extent_buffer *leaf,
1164                                  struct btrfs_extent_data_ref *ref,
1165                                  u64 root_objectid, u64 owner, u64 offset)
1166 {
1167         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1168             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1169             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1170                 return 0;
1171         return 1;
1172 }
1173
1174 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1175                                            struct btrfs_root *root,
1176                                            struct btrfs_path *path,
1177                                            u64 bytenr, u64 parent,
1178                                            u64 root_objectid,
1179                                            u64 owner, u64 offset)
1180 {
1181         struct btrfs_key key;
1182         struct btrfs_extent_data_ref *ref;
1183         struct extent_buffer *leaf;
1184         u32 nritems;
1185         int ret;
1186         int recow;
1187         int err = -ENOENT;
1188
1189         key.objectid = bytenr;
1190         if (parent) {
1191                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1192                 key.offset = parent;
1193         } else {
1194                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1195                 key.offset = hash_extent_data_ref(root_objectid,
1196                                                   owner, offset);
1197         }
1198 again:
1199         recow = 0;
1200         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1201         if (ret < 0) {
1202                 err = ret;
1203                 goto fail;
1204         }
1205
1206         if (parent) {
1207                 if (!ret)
1208                         return 0;
1209 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1210                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1211                 btrfs_release_path(path);
1212                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1213                 if (ret < 0) {
1214                         err = ret;
1215                         goto fail;
1216                 }
1217                 if (!ret)
1218                         return 0;
1219 #endif
1220                 goto fail;
1221         }
1222
1223         leaf = path->nodes[0];
1224         nritems = btrfs_header_nritems(leaf);
1225         while (1) {
1226                 if (path->slots[0] >= nritems) {
1227                         ret = btrfs_next_leaf(root, path);
1228                         if (ret < 0)
1229                                 err = ret;
1230                         if (ret)
1231                                 goto fail;
1232
1233                         leaf = path->nodes[0];
1234                         nritems = btrfs_header_nritems(leaf);
1235                         recow = 1;
1236                 }
1237
1238                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1239                 if (key.objectid != bytenr ||
1240                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1241                         goto fail;
1242
1243                 ref = btrfs_item_ptr(leaf, path->slots[0],
1244                                      struct btrfs_extent_data_ref);
1245
1246                 if (match_extent_data_ref(leaf, ref, root_objectid,
1247                                           owner, offset)) {
1248                         if (recow) {
1249                                 btrfs_release_path(path);
1250                                 goto again;
1251                         }
1252                         err = 0;
1253                         break;
1254                 }
1255                 path->slots[0]++;
1256         }
1257 fail:
1258         return err;
1259 }
1260
1261 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1262                                            struct btrfs_root *root,
1263                                            struct btrfs_path *path,
1264                                            u64 bytenr, u64 parent,
1265                                            u64 root_objectid, u64 owner,
1266                                            u64 offset, int refs_to_add)
1267 {
1268         struct btrfs_key key;
1269         struct extent_buffer *leaf;
1270         u32 size;
1271         u32 num_refs;
1272         int ret;
1273
1274         key.objectid = bytenr;
1275         if (parent) {
1276                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1277                 key.offset = parent;
1278                 size = sizeof(struct btrfs_shared_data_ref);
1279         } else {
1280                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1281                 key.offset = hash_extent_data_ref(root_objectid,
1282                                                   owner, offset);
1283                 size = sizeof(struct btrfs_extent_data_ref);
1284         }
1285
1286         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1287         if (ret && ret != -EEXIST)
1288                 goto fail;
1289
1290         leaf = path->nodes[0];
1291         if (parent) {
1292                 struct btrfs_shared_data_ref *ref;
1293                 ref = btrfs_item_ptr(leaf, path->slots[0],
1294                                      struct btrfs_shared_data_ref);
1295                 if (ret == 0) {
1296                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1297                 } else {
1298                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1299                         num_refs += refs_to_add;
1300                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1301                 }
1302         } else {
1303                 struct btrfs_extent_data_ref *ref;
1304                 while (ret == -EEXIST) {
1305                         ref = btrfs_item_ptr(leaf, path->slots[0],
1306                                              struct btrfs_extent_data_ref);
1307                         if (match_extent_data_ref(leaf, ref, root_objectid,
1308                                                   owner, offset))
1309                                 break;
1310                         btrfs_release_path(path);
1311                         key.offset++;
1312                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1313                                                       size);
1314                         if (ret && ret != -EEXIST)
1315                                 goto fail;
1316
1317                         leaf = path->nodes[0];
1318                 }
1319                 ref = btrfs_item_ptr(leaf, path->slots[0],
1320                                      struct btrfs_extent_data_ref);
1321                 if (ret == 0) {
1322                         btrfs_set_extent_data_ref_root(leaf, ref,
1323                                                        root_objectid);
1324                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1325                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1326                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1327                 } else {
1328                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1329                         num_refs += refs_to_add;
1330                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1331                 }
1332         }
1333         btrfs_mark_buffer_dirty(leaf);
1334         ret = 0;
1335 fail:
1336         btrfs_release_path(path);
1337         return ret;
1338 }
1339
1340 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1341                                            struct btrfs_root *root,
1342                                            struct btrfs_path *path,
1343                                            int refs_to_drop, int *last_ref)
1344 {
1345         struct btrfs_key key;
1346         struct btrfs_extent_data_ref *ref1 = NULL;
1347         struct btrfs_shared_data_ref *ref2 = NULL;
1348         struct extent_buffer *leaf;
1349         u32 num_refs = 0;
1350         int ret = 0;
1351
1352         leaf = path->nodes[0];
1353         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1354
1355         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1356                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1357                                       struct btrfs_extent_data_ref);
1358                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1359         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1360                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1361                                       struct btrfs_shared_data_ref);
1362                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1363 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1364         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1365                 struct btrfs_extent_ref_v0 *ref0;
1366                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1367                                       struct btrfs_extent_ref_v0);
1368                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1369 #endif
1370         } else {
1371                 BUG();
1372         }
1373
1374         BUG_ON(num_refs < refs_to_drop);
1375         num_refs -= refs_to_drop;
1376
1377         if (num_refs == 0) {
1378                 ret = btrfs_del_item(trans, root, path);
1379                 *last_ref = 1;
1380         } else {
1381                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1382                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1383                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1384                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1385 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1386                 else {
1387                         struct btrfs_extent_ref_v0 *ref0;
1388                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1389                                         struct btrfs_extent_ref_v0);
1390                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1391                 }
1392 #endif
1393                 btrfs_mark_buffer_dirty(leaf);
1394         }
1395         return ret;
1396 }
1397
1398 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1399                                           struct btrfs_extent_inline_ref *iref)
1400 {
1401         struct btrfs_key key;
1402         struct extent_buffer *leaf;
1403         struct btrfs_extent_data_ref *ref1;
1404         struct btrfs_shared_data_ref *ref2;
1405         u32 num_refs = 0;
1406
1407         leaf = path->nodes[0];
1408         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1409         if (iref) {
1410                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1411                     BTRFS_EXTENT_DATA_REF_KEY) {
1412                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1413                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1414                 } else {
1415                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1416                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1417                 }
1418         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1419                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1420                                       struct btrfs_extent_data_ref);
1421                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1422         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1423                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1424                                       struct btrfs_shared_data_ref);
1425                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1426 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1427         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1428                 struct btrfs_extent_ref_v0 *ref0;
1429                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1430                                       struct btrfs_extent_ref_v0);
1431                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1432 #endif
1433         } else {
1434                 WARN_ON(1);
1435         }
1436         return num_refs;
1437 }
1438
1439 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1440                                           struct btrfs_root *root,
1441                                           struct btrfs_path *path,
1442                                           u64 bytenr, u64 parent,
1443                                           u64 root_objectid)
1444 {
1445         struct btrfs_key key;
1446         int ret;
1447
1448         key.objectid = bytenr;
1449         if (parent) {
1450                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1451                 key.offset = parent;
1452         } else {
1453                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1454                 key.offset = root_objectid;
1455         }
1456
1457         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1458         if (ret > 0)
1459                 ret = -ENOENT;
1460 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1461         if (ret == -ENOENT && parent) {
1462                 btrfs_release_path(path);
1463                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1464                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1465                 if (ret > 0)
1466                         ret = -ENOENT;
1467         }
1468 #endif
1469         return ret;
1470 }
1471
1472 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1473                                           struct btrfs_root *root,
1474                                           struct btrfs_path *path,
1475                                           u64 bytenr, u64 parent,
1476                                           u64 root_objectid)
1477 {
1478         struct btrfs_key key;
1479         int ret;
1480
1481         key.objectid = bytenr;
1482         if (parent) {
1483                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1484                 key.offset = parent;
1485         } else {
1486                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1487                 key.offset = root_objectid;
1488         }
1489
1490         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1491         btrfs_release_path(path);
1492         return ret;
1493 }
1494
1495 static inline int extent_ref_type(u64 parent, u64 owner)
1496 {
1497         int type;
1498         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1499                 if (parent > 0)
1500                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1501                 else
1502                         type = BTRFS_TREE_BLOCK_REF_KEY;
1503         } else {
1504                 if (parent > 0)
1505                         type = BTRFS_SHARED_DATA_REF_KEY;
1506                 else
1507                         type = BTRFS_EXTENT_DATA_REF_KEY;
1508         }
1509         return type;
1510 }
1511
1512 static int find_next_key(struct btrfs_path *path, int level,
1513                          struct btrfs_key *key)
1514
1515 {
1516         for (; level < BTRFS_MAX_LEVEL; level++) {
1517                 if (!path->nodes[level])
1518                         break;
1519                 if (path->slots[level] + 1 >=
1520                     btrfs_header_nritems(path->nodes[level]))
1521                         continue;
1522                 if (level == 0)
1523                         btrfs_item_key_to_cpu(path->nodes[level], key,
1524                                               path->slots[level] + 1);
1525                 else
1526                         btrfs_node_key_to_cpu(path->nodes[level], key,
1527                                               path->slots[level] + 1);
1528                 return 0;
1529         }
1530         return 1;
1531 }
1532
1533 /*
1534  * look for inline back ref. if back ref is found, *ref_ret is set
1535  * to the address of inline back ref, and 0 is returned.
1536  *
1537  * if back ref isn't found, *ref_ret is set to the address where it
1538  * should be inserted, and -ENOENT is returned.
1539  *
1540  * if insert is true and there are too many inline back refs, the path
1541  * points to the extent item, and -EAGAIN is returned.
1542  *
1543  * NOTE: inline back refs are ordered in the same way that back ref
1544  *       items in the tree are ordered.
1545  */
1546 static noinline_for_stack
1547 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1548                                  struct btrfs_root *root,
1549                                  struct btrfs_path *path,
1550                                  struct btrfs_extent_inline_ref **ref_ret,
1551                                  u64 bytenr, u64 num_bytes,
1552                                  u64 parent, u64 root_objectid,
1553                                  u64 owner, u64 offset, int insert)
1554 {
1555         struct btrfs_key key;
1556         struct extent_buffer *leaf;
1557         struct btrfs_extent_item *ei;
1558         struct btrfs_extent_inline_ref *iref;
1559         u64 flags;
1560         u64 item_size;
1561         unsigned long ptr;
1562         unsigned long end;
1563         int extra_size;
1564         int type;
1565         int want;
1566         int ret;
1567         int err = 0;
1568         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1569                                                  SKINNY_METADATA);
1570
1571         key.objectid = bytenr;
1572         key.type = BTRFS_EXTENT_ITEM_KEY;
1573         key.offset = num_bytes;
1574
1575         want = extent_ref_type(parent, owner);
1576         if (insert) {
1577                 extra_size = btrfs_extent_inline_ref_size(want);
1578                 path->keep_locks = 1;
1579         } else
1580                 extra_size = -1;
1581
1582         /*
1583          * Owner is our parent level, so we can just add one to get the level
1584          * for the block we are interested in.
1585          */
1586         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1587                 key.type = BTRFS_METADATA_ITEM_KEY;
1588                 key.offset = owner;
1589         }
1590
1591 again:
1592         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1593         if (ret < 0) {
1594                 err = ret;
1595                 goto out;
1596         }
1597
1598         /*
1599          * We may be a newly converted file system which still has the old fat
1600          * extent entries for metadata, so try and see if we have one of those.
1601          */
1602         if (ret > 0 && skinny_metadata) {
1603                 skinny_metadata = false;
1604                 if (path->slots[0]) {
1605                         path->slots[0]--;
1606                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1607                                               path->slots[0]);
1608                         if (key.objectid == bytenr &&
1609                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1610                             key.offset == num_bytes)
1611                                 ret = 0;
1612                 }
1613                 if (ret) {
1614                         key.objectid = bytenr;
1615                         key.type = BTRFS_EXTENT_ITEM_KEY;
1616                         key.offset = num_bytes;
1617                         btrfs_release_path(path);
1618                         goto again;
1619                 }
1620         }
1621
1622         if (ret && !insert) {
1623                 err = -ENOENT;
1624                 goto out;
1625         } else if (WARN_ON(ret)) {
1626                 err = -EIO;
1627                 goto out;
1628         }
1629
1630         leaf = path->nodes[0];
1631         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1632 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1633         if (item_size < sizeof(*ei)) {
1634                 if (!insert) {
1635                         err = -ENOENT;
1636                         goto out;
1637                 }
1638                 ret = convert_extent_item_v0(trans, root, path, owner,
1639                                              extra_size);
1640                 if (ret < 0) {
1641                         err = ret;
1642                         goto out;
1643                 }
1644                 leaf = path->nodes[0];
1645                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1646         }
1647 #endif
1648         BUG_ON(item_size < sizeof(*ei));
1649
1650         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1651         flags = btrfs_extent_flags(leaf, ei);
1652
1653         ptr = (unsigned long)(ei + 1);
1654         end = (unsigned long)ei + item_size;
1655
1656         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1657                 ptr += sizeof(struct btrfs_tree_block_info);
1658                 BUG_ON(ptr > end);
1659         }
1660
1661         err = -ENOENT;
1662         while (1) {
1663                 if (ptr >= end) {
1664                         WARN_ON(ptr > end);
1665                         break;
1666                 }
1667                 iref = (struct btrfs_extent_inline_ref *)ptr;
1668                 type = btrfs_extent_inline_ref_type(leaf, iref);
1669                 if (want < type)
1670                         break;
1671                 if (want > type) {
1672                         ptr += btrfs_extent_inline_ref_size(type);
1673                         continue;
1674                 }
1675
1676                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1677                         struct btrfs_extent_data_ref *dref;
1678                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1679                         if (match_extent_data_ref(leaf, dref, root_objectid,
1680                                                   owner, offset)) {
1681                                 err = 0;
1682                                 break;
1683                         }
1684                         if (hash_extent_data_ref_item(leaf, dref) <
1685                             hash_extent_data_ref(root_objectid, owner, offset))
1686                                 break;
1687                 } else {
1688                         u64 ref_offset;
1689                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1690                         if (parent > 0) {
1691                                 if (parent == ref_offset) {
1692                                         err = 0;
1693                                         break;
1694                                 }
1695                                 if (ref_offset < parent)
1696                                         break;
1697                         } else {
1698                                 if (root_objectid == ref_offset) {
1699                                         err = 0;
1700                                         break;
1701                                 }
1702                                 if (ref_offset < root_objectid)
1703                                         break;
1704                         }
1705                 }
1706                 ptr += btrfs_extent_inline_ref_size(type);
1707         }
1708         if (err == -ENOENT && insert) {
1709                 if (item_size + extra_size >=
1710                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1711                         err = -EAGAIN;
1712                         goto out;
1713                 }
1714                 /*
1715                  * To add new inline back ref, we have to make sure
1716                  * there is no corresponding back ref item.
1717                  * For simplicity, we just do not add new inline back
1718                  * ref if there is any kind of item for this block
1719                  */
1720                 if (find_next_key(path, 0, &key) == 0 &&
1721                     key.objectid == bytenr &&
1722                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1723                         err = -EAGAIN;
1724                         goto out;
1725                 }
1726         }
1727         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1728 out:
1729         if (insert) {
1730                 path->keep_locks = 0;
1731                 btrfs_unlock_up_safe(path, 1);
1732         }
1733         return err;
1734 }
1735
1736 /*
1737  * helper to add new inline back ref
1738  */
1739 static noinline_for_stack
1740 void setup_inline_extent_backref(struct btrfs_root *root,
1741                                  struct btrfs_path *path,
1742                                  struct btrfs_extent_inline_ref *iref,
1743                                  u64 parent, u64 root_objectid,
1744                                  u64 owner, u64 offset, int refs_to_add,
1745                                  struct btrfs_delayed_extent_op *extent_op)
1746 {
1747         struct extent_buffer *leaf;
1748         struct btrfs_extent_item *ei;
1749         unsigned long ptr;
1750         unsigned long end;
1751         unsigned long item_offset;
1752         u64 refs;
1753         int size;
1754         int type;
1755
1756         leaf = path->nodes[0];
1757         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1758         item_offset = (unsigned long)iref - (unsigned long)ei;
1759
1760         type = extent_ref_type(parent, owner);
1761         size = btrfs_extent_inline_ref_size(type);
1762
1763         btrfs_extend_item(root, path, size);
1764
1765         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1766         refs = btrfs_extent_refs(leaf, ei);
1767         refs += refs_to_add;
1768         btrfs_set_extent_refs(leaf, ei, refs);
1769         if (extent_op)
1770                 __run_delayed_extent_op(extent_op, leaf, ei);
1771
1772         ptr = (unsigned long)ei + item_offset;
1773         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1774         if (ptr < end - size)
1775                 memmove_extent_buffer(leaf, ptr + size, ptr,
1776                                       end - size - ptr);
1777
1778         iref = (struct btrfs_extent_inline_ref *)ptr;
1779         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1780         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1781                 struct btrfs_extent_data_ref *dref;
1782                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1783                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1784                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1785                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1786                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1787         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1788                 struct btrfs_shared_data_ref *sref;
1789                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1790                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1791                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1792         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1793                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1794         } else {
1795                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1796         }
1797         btrfs_mark_buffer_dirty(leaf);
1798 }
1799
1800 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1801                                  struct btrfs_root *root,
1802                                  struct btrfs_path *path,
1803                                  struct btrfs_extent_inline_ref **ref_ret,
1804                                  u64 bytenr, u64 num_bytes, u64 parent,
1805                                  u64 root_objectid, u64 owner, u64 offset)
1806 {
1807         int ret;
1808
1809         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1810                                            bytenr, num_bytes, parent,
1811                                            root_objectid, owner, offset, 0);
1812         if (ret != -ENOENT)
1813                 return ret;
1814
1815         btrfs_release_path(path);
1816         *ref_ret = NULL;
1817
1818         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1819                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1820                                             root_objectid);
1821         } else {
1822                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1823                                              root_objectid, owner, offset);
1824         }
1825         return ret;
1826 }
1827
1828 /*
1829  * helper to update/remove inline back ref
1830  */
1831 static noinline_for_stack
1832 void update_inline_extent_backref(struct btrfs_root *root,
1833                                   struct btrfs_path *path,
1834                                   struct btrfs_extent_inline_ref *iref,
1835                                   int refs_to_mod,
1836                                   struct btrfs_delayed_extent_op *extent_op,
1837                                   int *last_ref)
1838 {
1839         struct extent_buffer *leaf;
1840         struct btrfs_extent_item *ei;
1841         struct btrfs_extent_data_ref *dref = NULL;
1842         struct btrfs_shared_data_ref *sref = NULL;
1843         unsigned long ptr;
1844         unsigned long end;
1845         u32 item_size;
1846         int size;
1847         int type;
1848         u64 refs;
1849
1850         leaf = path->nodes[0];
1851         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1852         refs = btrfs_extent_refs(leaf, ei);
1853         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1854         refs += refs_to_mod;
1855         btrfs_set_extent_refs(leaf, ei, refs);
1856         if (extent_op)
1857                 __run_delayed_extent_op(extent_op, leaf, ei);
1858
1859         type = btrfs_extent_inline_ref_type(leaf, iref);
1860
1861         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1862                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1863                 refs = btrfs_extent_data_ref_count(leaf, dref);
1864         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1865                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1866                 refs = btrfs_shared_data_ref_count(leaf, sref);
1867         } else {
1868                 refs = 1;
1869                 BUG_ON(refs_to_mod != -1);
1870         }
1871
1872         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1873         refs += refs_to_mod;
1874
1875         if (refs > 0) {
1876                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1877                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1878                 else
1879                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1880         } else {
1881                 *last_ref = 1;
1882                 size =  btrfs_extent_inline_ref_size(type);
1883                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1884                 ptr = (unsigned long)iref;
1885                 end = (unsigned long)ei + item_size;
1886                 if (ptr + size < end)
1887                         memmove_extent_buffer(leaf, ptr, ptr + size,
1888                                               end - ptr - size);
1889                 item_size -= size;
1890                 btrfs_truncate_item(root, path, item_size, 1);
1891         }
1892         btrfs_mark_buffer_dirty(leaf);
1893 }
1894
1895 static noinline_for_stack
1896 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1897                                  struct btrfs_root *root,
1898                                  struct btrfs_path *path,
1899                                  u64 bytenr, u64 num_bytes, u64 parent,
1900                                  u64 root_objectid, u64 owner,
1901                                  u64 offset, int refs_to_add,
1902                                  struct btrfs_delayed_extent_op *extent_op)
1903 {
1904         struct btrfs_extent_inline_ref *iref;
1905         int ret;
1906
1907         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1908                                            bytenr, num_bytes, parent,
1909                                            root_objectid, owner, offset, 1);
1910         if (ret == 0) {
1911                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1912                 update_inline_extent_backref(root, path, iref,
1913                                              refs_to_add, extent_op, NULL);
1914         } else if (ret == -ENOENT) {
1915                 setup_inline_extent_backref(root, path, iref, parent,
1916                                             root_objectid, owner, offset,
1917                                             refs_to_add, extent_op);
1918                 ret = 0;
1919         }
1920         return ret;
1921 }
1922
1923 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1924                                  struct btrfs_root *root,
1925                                  struct btrfs_path *path,
1926                                  u64 bytenr, u64 parent, u64 root_objectid,
1927                                  u64 owner, u64 offset, int refs_to_add)
1928 {
1929         int ret;
1930         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1931                 BUG_ON(refs_to_add != 1);
1932                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1933                                             parent, root_objectid);
1934         } else {
1935                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1936                                              parent, root_objectid,
1937                                              owner, offset, refs_to_add);
1938         }
1939         return ret;
1940 }
1941
1942 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1943                                  struct btrfs_root *root,
1944                                  struct btrfs_path *path,
1945                                  struct btrfs_extent_inline_ref *iref,
1946                                  int refs_to_drop, int is_data, int *last_ref)
1947 {
1948         int ret = 0;
1949
1950         BUG_ON(!is_data && refs_to_drop != 1);
1951         if (iref) {
1952                 update_inline_extent_backref(root, path, iref,
1953                                              -refs_to_drop, NULL, last_ref);
1954         } else if (is_data) {
1955                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1956                                              last_ref);
1957         } else {
1958                 *last_ref = 1;
1959                 ret = btrfs_del_item(trans, root, path);
1960         }
1961         return ret;
1962 }
1963
1964 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1965 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1966                                u64 *discarded_bytes)
1967 {
1968         int j, ret = 0;
1969         u64 bytes_left, end;
1970         u64 aligned_start = ALIGN(start, 1 << 9);
1971
1972         if (WARN_ON(start != aligned_start)) {
1973                 len -= aligned_start - start;
1974                 len = round_down(len, 1 << 9);
1975                 start = aligned_start;
1976         }
1977
1978         *discarded_bytes = 0;
1979
1980         if (!len)
1981                 return 0;
1982
1983         end = start + len;
1984         bytes_left = len;
1985
1986         /* Skip any superblocks on this device. */
1987         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1988                 u64 sb_start = btrfs_sb_offset(j);
1989                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1990                 u64 size = sb_start - start;
1991
1992                 if (!in_range(sb_start, start, bytes_left) &&
1993                     !in_range(sb_end, start, bytes_left) &&
1994                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1995                         continue;
1996
1997                 /*
1998                  * Superblock spans beginning of range.  Adjust start and
1999                  * try again.
2000                  */
2001                 if (sb_start <= start) {
2002                         start += sb_end - start;
2003                         if (start > end) {
2004                                 bytes_left = 0;
2005                                 break;
2006                         }
2007                         bytes_left = end - start;
2008                         continue;
2009                 }
2010
2011                 if (size) {
2012                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2013                                                    GFP_NOFS, 0);
2014                         if (!ret)
2015                                 *discarded_bytes += size;
2016                         else if (ret != -EOPNOTSUPP)
2017                                 return ret;
2018                 }
2019
2020                 start = sb_end;
2021                 if (start > end) {
2022                         bytes_left = 0;
2023                         break;
2024                 }
2025                 bytes_left = end - start;
2026         }
2027
2028         if (bytes_left) {
2029                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2030                                            GFP_NOFS, 0);
2031                 if (!ret)
2032                         *discarded_bytes += bytes_left;
2033         }
2034         return ret;
2035 }
2036
2037 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
2038                          u64 num_bytes, u64 *actual_bytes)
2039 {
2040         int ret;
2041         u64 discarded_bytes = 0;
2042         struct btrfs_bio *bbio = NULL;
2043
2044
2045         /*
2046          * Avoid races with device replace and make sure our bbio has devices
2047          * associated to its stripes that don't go away while we are discarding.
2048          */
2049         btrfs_bio_counter_inc_blocked(root->fs_info);
2050         /* Tell the block device(s) that the sectors can be discarded */
2051         ret = btrfs_map_block(root->fs_info, REQ_OP_DISCARD,
2052                               bytenr, &num_bytes, &bbio, 0);
2053         /* Error condition is -ENOMEM */
2054         if (!ret) {
2055                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2056                 int i;
2057
2058
2059                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2060                         u64 bytes;
2061                         if (!stripe->dev->can_discard)
2062                                 continue;
2063
2064                         ret = btrfs_issue_discard(stripe->dev->bdev,
2065                                                   stripe->physical,
2066                                                   stripe->length,
2067                                                   &bytes);
2068                         if (!ret)
2069                                 discarded_bytes += bytes;
2070                         else if (ret != -EOPNOTSUPP)
2071                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2072
2073                         /*
2074                          * Just in case we get back EOPNOTSUPP for some reason,
2075                          * just ignore the return value so we don't screw up
2076                          * people calling discard_extent.
2077                          */
2078                         ret = 0;
2079                 }
2080                 btrfs_put_bbio(bbio);
2081         }
2082         btrfs_bio_counter_dec(root->fs_info);
2083
2084         if (actual_bytes)
2085                 *actual_bytes = discarded_bytes;
2086
2087
2088         if (ret == -EOPNOTSUPP)
2089                 ret = 0;
2090         return ret;
2091 }
2092
2093 /* Can return -ENOMEM */
2094 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2095                          struct btrfs_root *root,
2096                          u64 bytenr, u64 num_bytes, u64 parent,
2097                          u64 root_objectid, u64 owner, u64 offset)
2098 {
2099         int ret;
2100         struct btrfs_fs_info *fs_info = root->fs_info;
2101
2102         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2103                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2104
2105         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2106                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2107                                         num_bytes,
2108                                         parent, root_objectid, (int)owner,
2109                                         BTRFS_ADD_DELAYED_REF, NULL);
2110         } else {
2111                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2112                                         num_bytes, parent, root_objectid,
2113                                         owner, offset, 0,
2114                                         BTRFS_ADD_DELAYED_REF, NULL);
2115         }
2116         return ret;
2117 }
2118
2119 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2120                                   struct btrfs_root *root,
2121                                   struct btrfs_delayed_ref_node *node,
2122                                   u64 parent, u64 root_objectid,
2123                                   u64 owner, u64 offset, int refs_to_add,
2124                                   struct btrfs_delayed_extent_op *extent_op)
2125 {
2126         struct btrfs_fs_info *fs_info = root->fs_info;
2127         struct btrfs_path *path;
2128         struct extent_buffer *leaf;
2129         struct btrfs_extent_item *item;
2130         struct btrfs_key key;
2131         u64 bytenr = node->bytenr;
2132         u64 num_bytes = node->num_bytes;
2133         u64 refs;
2134         int ret;
2135
2136         path = btrfs_alloc_path();
2137         if (!path)
2138                 return -ENOMEM;
2139
2140         path->reada = READA_FORWARD;
2141         path->leave_spinning = 1;
2142         /* this will setup the path even if it fails to insert the back ref */
2143         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2144                                            bytenr, num_bytes, parent,
2145                                            root_objectid, owner, offset,
2146                                            refs_to_add, extent_op);
2147         if ((ret < 0 && ret != -EAGAIN) || !ret)
2148                 goto out;
2149
2150         /*
2151          * Ok we had -EAGAIN which means we didn't have space to insert and
2152          * inline extent ref, so just update the reference count and add a
2153          * normal backref.
2154          */
2155         leaf = path->nodes[0];
2156         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2157         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2158         refs = btrfs_extent_refs(leaf, item);
2159         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2160         if (extent_op)
2161                 __run_delayed_extent_op(extent_op, leaf, item);
2162
2163         btrfs_mark_buffer_dirty(leaf);
2164         btrfs_release_path(path);
2165
2166         path->reada = READA_FORWARD;
2167         path->leave_spinning = 1;
2168         /* now insert the actual backref */
2169         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2170                                     path, bytenr, parent, root_objectid,
2171                                     owner, offset, refs_to_add);
2172         if (ret)
2173                 btrfs_abort_transaction(trans, root, ret);
2174 out:
2175         btrfs_free_path(path);
2176         return ret;
2177 }
2178
2179 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2180                                 struct btrfs_root *root,
2181                                 struct btrfs_delayed_ref_node *node,
2182                                 struct btrfs_delayed_extent_op *extent_op,
2183                                 int insert_reserved)
2184 {
2185         int ret = 0;
2186         struct btrfs_delayed_data_ref *ref;
2187         struct btrfs_key ins;
2188         u64 parent = 0;
2189         u64 ref_root = 0;
2190         u64 flags = 0;
2191
2192         ins.objectid = node->bytenr;
2193         ins.offset = node->num_bytes;
2194         ins.type = BTRFS_EXTENT_ITEM_KEY;
2195
2196         ref = btrfs_delayed_node_to_data_ref(node);
2197         trace_run_delayed_data_ref(node, ref, node->action);
2198
2199         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2200                 parent = ref->parent;
2201         ref_root = ref->root;
2202
2203         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2204                 if (extent_op)
2205                         flags |= extent_op->flags_to_set;
2206                 ret = alloc_reserved_file_extent(trans, root,
2207                                                  parent, ref_root, flags,
2208                                                  ref->objectid, ref->offset,
2209                                                  &ins, node->ref_mod);
2210         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2211                 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2212                                              ref_root, ref->objectid,
2213                                              ref->offset, node->ref_mod,
2214                                              extent_op);
2215         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2216                 ret = __btrfs_free_extent(trans, root, node, parent,
2217                                           ref_root, ref->objectid,
2218                                           ref->offset, node->ref_mod,
2219                                           extent_op);
2220         } else {
2221                 BUG();
2222         }
2223         return ret;
2224 }
2225
2226 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2227                                     struct extent_buffer *leaf,
2228                                     struct btrfs_extent_item *ei)
2229 {
2230         u64 flags = btrfs_extent_flags(leaf, ei);
2231         if (extent_op->update_flags) {
2232                 flags |= extent_op->flags_to_set;
2233                 btrfs_set_extent_flags(leaf, ei, flags);
2234         }
2235
2236         if (extent_op->update_key) {
2237                 struct btrfs_tree_block_info *bi;
2238                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2239                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2240                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2241         }
2242 }
2243
2244 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2245                                  struct btrfs_root *root,
2246                                  struct btrfs_delayed_ref_node *node,
2247                                  struct btrfs_delayed_extent_op *extent_op)
2248 {
2249         struct btrfs_key key;
2250         struct btrfs_path *path;
2251         struct btrfs_extent_item *ei;
2252         struct extent_buffer *leaf;
2253         u32 item_size;
2254         int ret;
2255         int err = 0;
2256         int metadata = !extent_op->is_data;
2257
2258         if (trans->aborted)
2259                 return 0;
2260
2261         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2262                 metadata = 0;
2263
2264         path = btrfs_alloc_path();
2265         if (!path)
2266                 return -ENOMEM;
2267
2268         key.objectid = node->bytenr;
2269
2270         if (metadata) {
2271                 key.type = BTRFS_METADATA_ITEM_KEY;
2272                 key.offset = extent_op->level;
2273         } else {
2274                 key.type = BTRFS_EXTENT_ITEM_KEY;
2275                 key.offset = node->num_bytes;
2276         }
2277
2278 again:
2279         path->reada = READA_FORWARD;
2280         path->leave_spinning = 1;
2281         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2282                                 path, 0, 1);
2283         if (ret < 0) {
2284                 err = ret;
2285                 goto out;
2286         }
2287         if (ret > 0) {
2288                 if (metadata) {
2289                         if (path->slots[0] > 0) {
2290                                 path->slots[0]--;
2291                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2292                                                       path->slots[0]);
2293                                 if (key.objectid == node->bytenr &&
2294                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2295                                     key.offset == node->num_bytes)
2296                                         ret = 0;
2297                         }
2298                         if (ret > 0) {
2299                                 btrfs_release_path(path);
2300                                 metadata = 0;
2301
2302                                 key.objectid = node->bytenr;
2303                                 key.offset = node->num_bytes;
2304                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2305                                 goto again;
2306                         }
2307                 } else {
2308                         err = -EIO;
2309                         goto out;
2310                 }
2311         }
2312
2313         leaf = path->nodes[0];
2314         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2315 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2316         if (item_size < sizeof(*ei)) {
2317                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2318                                              path, (u64)-1, 0);
2319                 if (ret < 0) {
2320                         err = ret;
2321                         goto out;
2322                 }
2323                 leaf = path->nodes[0];
2324                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2325         }
2326 #endif
2327         BUG_ON(item_size < sizeof(*ei));
2328         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2329         __run_delayed_extent_op(extent_op, leaf, ei);
2330
2331         btrfs_mark_buffer_dirty(leaf);
2332 out:
2333         btrfs_free_path(path);
2334         return err;
2335 }
2336
2337 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2338                                 struct btrfs_root *root,
2339                                 struct btrfs_delayed_ref_node *node,
2340                                 struct btrfs_delayed_extent_op *extent_op,
2341                                 int insert_reserved)
2342 {
2343         int ret = 0;
2344         struct btrfs_delayed_tree_ref *ref;
2345         struct btrfs_key ins;
2346         u64 parent = 0;
2347         u64 ref_root = 0;
2348         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2349                                                  SKINNY_METADATA);
2350
2351         ref = btrfs_delayed_node_to_tree_ref(node);
2352         trace_run_delayed_tree_ref(node, ref, node->action);
2353
2354         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2355                 parent = ref->parent;
2356         ref_root = ref->root;
2357
2358         ins.objectid = node->bytenr;
2359         if (skinny_metadata) {
2360                 ins.offset = ref->level;
2361                 ins.type = BTRFS_METADATA_ITEM_KEY;
2362         } else {
2363                 ins.offset = node->num_bytes;
2364                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2365         }
2366
2367         BUG_ON(node->ref_mod != 1);
2368         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2369                 BUG_ON(!extent_op || !extent_op->update_flags);
2370                 ret = alloc_reserved_tree_block(trans, root,
2371                                                 parent, ref_root,
2372                                                 extent_op->flags_to_set,
2373                                                 &extent_op->key,
2374                                                 ref->level, &ins);
2375         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2376                 ret = __btrfs_inc_extent_ref(trans, root, node,
2377                                              parent, ref_root,
2378                                              ref->level, 0, 1,
2379                                              extent_op);
2380         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2381                 ret = __btrfs_free_extent(trans, root, node,
2382                                           parent, ref_root,
2383                                           ref->level, 0, 1, extent_op);
2384         } else {
2385                 BUG();
2386         }
2387         return ret;
2388 }
2389
2390 /* helper function to actually process a single delayed ref entry */
2391 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2392                                struct btrfs_root *root,
2393                                struct btrfs_delayed_ref_node *node,
2394                                struct btrfs_delayed_extent_op *extent_op,
2395                                int insert_reserved)
2396 {
2397         int ret = 0;
2398
2399         if (trans->aborted) {
2400                 if (insert_reserved)
2401                         btrfs_pin_extent(root, node->bytenr,
2402                                          node->num_bytes, 1);
2403                 return 0;
2404         }
2405
2406         if (btrfs_delayed_ref_is_head(node)) {
2407                 struct btrfs_delayed_ref_head *head;
2408                 /*
2409                  * we've hit the end of the chain and we were supposed
2410                  * to insert this extent into the tree.  But, it got
2411                  * deleted before we ever needed to insert it, so all
2412                  * we have to do is clean up the accounting
2413                  */
2414                 BUG_ON(extent_op);
2415                 head = btrfs_delayed_node_to_head(node);
2416                 trace_run_delayed_ref_head(node, head, node->action);
2417
2418                 if (insert_reserved) {
2419                         btrfs_pin_extent(root, node->bytenr,
2420                                          node->num_bytes, 1);
2421                         if (head->is_data) {
2422                                 ret = btrfs_del_csums(trans, root,
2423                                                       node->bytenr,
2424                                                       node->num_bytes);
2425                         }
2426                 }
2427
2428                 /* Also free its reserved qgroup space */
2429                 btrfs_qgroup_free_delayed_ref(root->fs_info,
2430                                               head->qgroup_ref_root,
2431                                               head->qgroup_reserved);
2432                 return ret;
2433         }
2434
2435         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2436             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2437                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2438                                            insert_reserved);
2439         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2440                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2441                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2442                                            insert_reserved);
2443         else
2444                 BUG();
2445         return ret;
2446 }
2447
2448 static inline struct btrfs_delayed_ref_node *
2449 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2450 {
2451         struct btrfs_delayed_ref_node *ref;
2452
2453         if (list_empty(&head->ref_list))
2454                 return NULL;
2455
2456         /*
2457          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2458          * This is to prevent a ref count from going down to zero, which deletes
2459          * the extent item from the extent tree, when there still are references
2460          * to add, which would fail because they would not find the extent item.
2461          */
2462         list_for_each_entry(ref, &head->ref_list, list) {
2463                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2464                         return ref;
2465         }
2466
2467         return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2468                           list);
2469 }
2470
2471 /*
2472  * Returns 0 on success or if called with an already aborted transaction.
2473  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2474  */
2475 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2476                                              struct btrfs_root *root,
2477                                              unsigned long nr)
2478 {
2479         struct btrfs_delayed_ref_root *delayed_refs;
2480         struct btrfs_delayed_ref_node *ref;
2481         struct btrfs_delayed_ref_head *locked_ref = NULL;
2482         struct btrfs_delayed_extent_op *extent_op;
2483         struct btrfs_fs_info *fs_info = root->fs_info;
2484         ktime_t start = ktime_get();
2485         int ret;
2486         unsigned long count = 0;
2487         unsigned long actual_count = 0;
2488         int must_insert_reserved = 0;
2489
2490         delayed_refs = &trans->transaction->delayed_refs;
2491         while (1) {
2492                 if (!locked_ref) {
2493                         if (count >= nr)
2494                                 break;
2495
2496                         spin_lock(&delayed_refs->lock);
2497                         locked_ref = btrfs_select_ref_head(trans);
2498                         if (!locked_ref) {
2499                                 spin_unlock(&delayed_refs->lock);
2500                                 break;
2501                         }
2502
2503                         /* grab the lock that says we are going to process
2504                          * all the refs for this head */
2505                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2506                         spin_unlock(&delayed_refs->lock);
2507                         /*
2508                          * we may have dropped the spin lock to get the head
2509                          * mutex lock, and that might have given someone else
2510                          * time to free the head.  If that's true, it has been
2511                          * removed from our list and we can move on.
2512                          */
2513                         if (ret == -EAGAIN) {
2514                                 locked_ref = NULL;
2515                                 count++;
2516                                 continue;
2517                         }
2518                 }
2519
2520                 /*
2521                  * We need to try and merge add/drops of the same ref since we
2522                  * can run into issues with relocate dropping the implicit ref
2523                  * and then it being added back again before the drop can
2524                  * finish.  If we merged anything we need to re-loop so we can
2525                  * get a good ref.
2526                  * Or we can get node references of the same type that weren't
2527                  * merged when created due to bumps in the tree mod seq, and
2528                  * we need to merge them to prevent adding an inline extent
2529                  * backref before dropping it (triggering a BUG_ON at
2530                  * insert_inline_extent_backref()).
2531                  */
2532                 spin_lock(&locked_ref->lock);
2533                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2534                                          locked_ref);
2535
2536                 /*
2537                  * locked_ref is the head node, so we have to go one
2538                  * node back for any delayed ref updates
2539                  */
2540                 ref = select_delayed_ref(locked_ref);
2541
2542                 if (ref && ref->seq &&
2543                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2544                         spin_unlock(&locked_ref->lock);
2545                         btrfs_delayed_ref_unlock(locked_ref);
2546                         spin_lock(&delayed_refs->lock);
2547                         locked_ref->processing = 0;
2548                         delayed_refs->num_heads_ready++;
2549                         spin_unlock(&delayed_refs->lock);
2550                         locked_ref = NULL;
2551                         cond_resched();
2552                         count++;
2553                         continue;
2554                 }
2555
2556                 /*
2557                  * record the must insert reserved flag before we
2558                  * drop the spin lock.
2559                  */
2560                 must_insert_reserved = locked_ref->must_insert_reserved;
2561                 locked_ref->must_insert_reserved = 0;
2562
2563                 extent_op = locked_ref->extent_op;
2564                 locked_ref->extent_op = NULL;
2565
2566                 if (!ref) {
2567
2568
2569                         /* All delayed refs have been processed, Go ahead
2570                          * and send the head node to run_one_delayed_ref,
2571                          * so that any accounting fixes can happen
2572                          */
2573                         ref = &locked_ref->node;
2574
2575                         if (extent_op && must_insert_reserved) {
2576                                 btrfs_free_delayed_extent_op(extent_op);
2577                                 extent_op = NULL;
2578                         }
2579
2580                         if (extent_op) {
2581                                 spin_unlock(&locked_ref->lock);
2582                                 ret = run_delayed_extent_op(trans, root,
2583                                                             ref, extent_op);
2584                                 btrfs_free_delayed_extent_op(extent_op);
2585
2586                                 if (ret) {
2587                                         /*
2588                                          * Need to reset must_insert_reserved if
2589                                          * there was an error so the abort stuff
2590                                          * can cleanup the reserved space
2591                                          * properly.
2592                                          */
2593                                         if (must_insert_reserved)
2594                                                 locked_ref->must_insert_reserved = 1;
2595                                         locked_ref->processing = 0;
2596                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2597                                         btrfs_delayed_ref_unlock(locked_ref);
2598                                         return ret;
2599                                 }
2600                                 continue;
2601                         }
2602
2603                         /*
2604                          * Need to drop our head ref lock and re-acquire the
2605                          * delayed ref lock and then re-check to make sure
2606                          * nobody got added.
2607                          */
2608                         spin_unlock(&locked_ref->lock);
2609                         spin_lock(&delayed_refs->lock);
2610                         spin_lock(&locked_ref->lock);
2611                         if (!list_empty(&locked_ref->ref_list) ||
2612                             locked_ref->extent_op) {
2613                                 spin_unlock(&locked_ref->lock);
2614                                 spin_unlock(&delayed_refs->lock);
2615                                 continue;
2616                         }
2617                         ref->in_tree = 0;
2618                         delayed_refs->num_heads--;
2619                         rb_erase(&locked_ref->href_node,
2620                                  &delayed_refs->href_root);
2621                         spin_unlock(&delayed_refs->lock);
2622                 } else {
2623                         actual_count++;
2624                         ref->in_tree = 0;
2625                         list_del(&ref->list);
2626                 }
2627                 atomic_dec(&delayed_refs->num_entries);
2628
2629                 if (!btrfs_delayed_ref_is_head(ref)) {
2630                         /*
2631                          * when we play the delayed ref, also correct the
2632                          * ref_mod on head
2633                          */
2634                         switch (ref->action) {
2635                         case BTRFS_ADD_DELAYED_REF:
2636                         case BTRFS_ADD_DELAYED_EXTENT:
2637                                 locked_ref->node.ref_mod -= ref->ref_mod;
2638                                 break;
2639                         case BTRFS_DROP_DELAYED_REF:
2640                                 locked_ref->node.ref_mod += ref->ref_mod;
2641                                 break;
2642                         default:
2643                                 WARN_ON(1);
2644                         }
2645                 }
2646                 spin_unlock(&locked_ref->lock);
2647
2648                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2649                                           must_insert_reserved);
2650
2651                 btrfs_free_delayed_extent_op(extent_op);
2652                 if (ret) {
2653                         locked_ref->processing = 0;
2654                         btrfs_delayed_ref_unlock(locked_ref);
2655                         btrfs_put_delayed_ref(ref);
2656                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2657                         return ret;
2658                 }
2659
2660                 /*
2661                  * If this node is a head, that means all the refs in this head
2662                  * have been dealt with, and we will pick the next head to deal
2663                  * with, so we must unlock the head and drop it from the cluster
2664                  * list before we release it.
2665                  */
2666                 if (btrfs_delayed_ref_is_head(ref)) {
2667                         if (locked_ref->is_data &&
2668                             locked_ref->total_ref_mod < 0) {
2669                                 spin_lock(&delayed_refs->lock);
2670                                 delayed_refs->pending_csums -= ref->num_bytes;
2671                                 spin_unlock(&delayed_refs->lock);
2672                         }
2673                         btrfs_delayed_ref_unlock(locked_ref);
2674                         locked_ref = NULL;
2675                 }
2676                 btrfs_put_delayed_ref(ref);
2677                 count++;
2678                 cond_resched();
2679         }
2680
2681         /*
2682          * We don't want to include ref heads since we can have empty ref heads
2683          * and those will drastically skew our runtime down since we just do
2684          * accounting, no actual extent tree updates.
2685          */
2686         if (actual_count > 0) {
2687                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2688                 u64 avg;
2689
2690                 /*
2691                  * We weigh the current average higher than our current runtime
2692                  * to avoid large swings in the average.
2693                  */
2694                 spin_lock(&delayed_refs->lock);
2695                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2696                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2697                 spin_unlock(&delayed_refs->lock);
2698         }
2699         return 0;
2700 }
2701
2702 #ifdef SCRAMBLE_DELAYED_REFS
2703 /*
2704  * Normally delayed refs get processed in ascending bytenr order. This
2705  * correlates in most cases to the order added. To expose dependencies on this
2706  * order, we start to process the tree in the middle instead of the beginning
2707  */
2708 static u64 find_middle(struct rb_root *root)
2709 {
2710         struct rb_node *n = root->rb_node;
2711         struct btrfs_delayed_ref_node *entry;
2712         int alt = 1;
2713         u64 middle;
2714         u64 first = 0, last = 0;
2715
2716         n = rb_first(root);
2717         if (n) {
2718                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2719                 first = entry->bytenr;
2720         }
2721         n = rb_last(root);
2722         if (n) {
2723                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2724                 last = entry->bytenr;
2725         }
2726         n = root->rb_node;
2727
2728         while (n) {
2729                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2730                 WARN_ON(!entry->in_tree);
2731
2732                 middle = entry->bytenr;
2733
2734                 if (alt)
2735                         n = n->rb_left;
2736                 else
2737                         n = n->rb_right;
2738
2739                 alt = 1 - alt;
2740         }
2741         return middle;
2742 }
2743 #endif
2744
2745 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2746 {
2747         u64 num_bytes;
2748
2749         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2750                              sizeof(struct btrfs_extent_inline_ref));
2751         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2752                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2753
2754         /*
2755          * We don't ever fill up leaves all the way so multiply by 2 just to be
2756          * closer to what we're really going to want to use.
2757          */
2758         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2759 }
2760
2761 /*
2762  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2763  * would require to store the csums for that many bytes.
2764  */
2765 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2766 {
2767         u64 csum_size;
2768         u64 num_csums_per_leaf;
2769         u64 num_csums;
2770
2771         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
2772         num_csums_per_leaf = div64_u64(csum_size,
2773                         (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2774         num_csums = div64_u64(csum_bytes, root->sectorsize);
2775         num_csums += num_csums_per_leaf - 1;
2776         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2777         return num_csums;
2778 }
2779
2780 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2781                                        struct btrfs_root *root)
2782 {
2783         struct btrfs_block_rsv *global_rsv;
2784         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2785         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2786         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2787         u64 num_bytes, num_dirty_bgs_bytes;
2788         int ret = 0;
2789
2790         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2791         num_heads = heads_to_leaves(root, num_heads);
2792         if (num_heads > 1)
2793                 num_bytes += (num_heads - 1) * root->nodesize;
2794         num_bytes <<= 1;
2795         num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2796         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2797                                                              num_dirty_bgs);
2798         global_rsv = &root->fs_info->global_block_rsv;
2799
2800         /*
2801          * If we can't allocate any more chunks lets make sure we have _lots_ of
2802          * wiggle room since running delayed refs can create more delayed refs.
2803          */
2804         if (global_rsv->space_info->full) {
2805                 num_dirty_bgs_bytes <<= 1;
2806                 num_bytes <<= 1;
2807         }
2808
2809         spin_lock(&global_rsv->lock);
2810         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2811                 ret = 1;
2812         spin_unlock(&global_rsv->lock);
2813         return ret;
2814 }
2815
2816 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2817                                        struct btrfs_root *root)
2818 {
2819         struct btrfs_fs_info *fs_info = root->fs_info;
2820         u64 num_entries =
2821                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2822         u64 avg_runtime;
2823         u64 val;
2824
2825         smp_mb();
2826         avg_runtime = fs_info->avg_delayed_ref_runtime;
2827         val = num_entries * avg_runtime;
2828         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2829                 return 1;
2830         if (val >= NSEC_PER_SEC / 2)
2831                 return 2;
2832
2833         return btrfs_check_space_for_delayed_refs(trans, root);
2834 }
2835
2836 struct async_delayed_refs {
2837         struct btrfs_root *root;
2838         u64 transid;
2839         int count;
2840         int error;
2841         int sync;
2842         struct completion wait;
2843         struct btrfs_work work;
2844 };
2845
2846 static void delayed_ref_async_start(struct btrfs_work *work)
2847 {
2848         struct async_delayed_refs *async;
2849         struct btrfs_trans_handle *trans;
2850         int ret;
2851
2852         async = container_of(work, struct async_delayed_refs, work);
2853
2854         /* if the commit is already started, we don't need to wait here */
2855         if (btrfs_transaction_blocked(async->root->fs_info))
2856                 goto done;
2857
2858         trans = btrfs_join_transaction(async->root);
2859         if (IS_ERR(trans)) {
2860                 async->error = PTR_ERR(trans);
2861                 goto done;
2862         }
2863
2864         /*
2865          * trans->sync means that when we call end_transaction, we won't
2866          * wait on delayed refs
2867          */
2868         trans->sync = true;
2869
2870         /* Don't bother flushing if we got into a different transaction */
2871         if (trans->transid > async->transid)
2872                 goto end;
2873
2874         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2875         if (ret)
2876                 async->error = ret;
2877 end:
2878         ret = btrfs_end_transaction(trans, async->root);
2879         if (ret && !async->error)
2880                 async->error = ret;
2881 done:
2882         if (async->sync)
2883                 complete(&async->wait);
2884         else
2885                 kfree(async);
2886 }
2887
2888 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2889                                  unsigned long count, u64 transid, int wait)
2890 {
2891         struct async_delayed_refs *async;
2892         int ret;
2893
2894         async = kmalloc(sizeof(*async), GFP_NOFS);
2895         if (!async)
2896                 return -ENOMEM;
2897
2898         async->root = root->fs_info->tree_root;
2899         async->count = count;
2900         async->error = 0;
2901         async->transid = transid;
2902         if (wait)
2903                 async->sync = 1;
2904         else
2905                 async->sync = 0;
2906         init_completion(&async->wait);
2907
2908         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2909                         delayed_ref_async_start, NULL, NULL);
2910
2911         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2912
2913         if (wait) {
2914                 wait_for_completion(&async->wait);
2915                 ret = async->error;
2916                 kfree(async);
2917                 return ret;
2918         }
2919         return 0;
2920 }
2921
2922 /*
2923  * this starts processing the delayed reference count updates and
2924  * extent insertions we have queued up so far.  count can be
2925  * 0, which means to process everything in the tree at the start
2926  * of the run (but not newly added entries), or it can be some target
2927  * number you'd like to process.
2928  *
2929  * Returns 0 on success or if called with an aborted transaction
2930  * Returns <0 on error and aborts the transaction
2931  */
2932 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2933                            struct btrfs_root *root, unsigned long count)
2934 {
2935         struct rb_node *node;
2936         struct btrfs_delayed_ref_root *delayed_refs;
2937         struct btrfs_delayed_ref_head *head;
2938         int ret;
2939         int run_all = count == (unsigned long)-1;
2940         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2941
2942         /* We'll clean this up in btrfs_cleanup_transaction */
2943         if (trans->aborted)
2944                 return 0;
2945
2946         if (root->fs_info->creating_free_space_tree)
2947                 return 0;
2948
2949         if (root == root->fs_info->extent_root)
2950                 root = root->fs_info->tree_root;
2951
2952         delayed_refs = &trans->transaction->delayed_refs;
2953         if (count == 0)
2954                 count = atomic_read(&delayed_refs->num_entries) * 2;
2955
2956 again:
2957 #ifdef SCRAMBLE_DELAYED_REFS
2958         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2959 #endif
2960         trans->can_flush_pending_bgs = false;
2961         ret = __btrfs_run_delayed_refs(trans, root, count);
2962         if (ret < 0) {
2963                 btrfs_abort_transaction(trans, root, ret);
2964                 return ret;
2965         }
2966
2967         if (run_all) {
2968                 if (!list_empty(&trans->new_bgs))
2969                         btrfs_create_pending_block_groups(trans, root);
2970
2971                 spin_lock(&delayed_refs->lock);
2972                 node = rb_first(&delayed_refs->href_root);
2973                 if (!node) {
2974                         spin_unlock(&delayed_refs->lock);
2975                         goto out;
2976                 }
2977                 count = (unsigned long)-1;
2978
2979                 while (node) {
2980                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2981                                         href_node);
2982                         if (btrfs_delayed_ref_is_head(&head->node)) {
2983                                 struct btrfs_delayed_ref_node *ref;
2984
2985                                 ref = &head->node;
2986                                 atomic_inc(&ref->refs);
2987
2988                                 spin_unlock(&delayed_refs->lock);
2989                                 /*
2990                                  * Mutex was contended, block until it's
2991                                  * released and try again
2992                                  */
2993                                 mutex_lock(&head->mutex);
2994                                 mutex_unlock(&head->mutex);
2995
2996                                 btrfs_put_delayed_ref(ref);
2997                                 cond_resched();
2998                                 goto again;
2999                         } else {
3000                                 WARN_ON(1);
3001                         }
3002                         node = rb_next(node);
3003                 }
3004                 spin_unlock(&delayed_refs->lock);
3005                 cond_resched();
3006                 goto again;
3007         }
3008 out:
3009         assert_qgroups_uptodate(trans);
3010         trans->can_flush_pending_bgs = can_flush_pending_bgs;
3011         return 0;
3012 }
3013
3014 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3015                                 struct btrfs_root *root,
3016                                 u64 bytenr, u64 num_bytes, u64 flags,
3017                                 int level, int is_data)
3018 {
3019         struct btrfs_delayed_extent_op *extent_op;
3020         int ret;
3021
3022         extent_op = btrfs_alloc_delayed_extent_op();
3023         if (!extent_op)
3024                 return -ENOMEM;
3025
3026         extent_op->flags_to_set = flags;
3027         extent_op->update_flags = true;
3028         extent_op->update_key = false;
3029         extent_op->is_data = is_data ? true : false;
3030         extent_op->level = level;
3031
3032         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
3033                                           num_bytes, extent_op);
3034         if (ret)
3035                 btrfs_free_delayed_extent_op(extent_op);
3036         return ret;
3037 }
3038
3039 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
3040                                       struct btrfs_root *root,
3041                                       struct btrfs_path *path,
3042                                       u64 objectid, u64 offset, u64 bytenr)
3043 {
3044         struct btrfs_delayed_ref_head *head;
3045         struct btrfs_delayed_ref_node *ref;
3046         struct btrfs_delayed_data_ref *data_ref;
3047         struct btrfs_delayed_ref_root *delayed_refs;
3048         int ret = 0;
3049
3050         delayed_refs = &trans->transaction->delayed_refs;
3051         spin_lock(&delayed_refs->lock);
3052         head = btrfs_find_delayed_ref_head(trans, bytenr);
3053         if (!head) {
3054                 spin_unlock(&delayed_refs->lock);
3055                 return 0;
3056         }
3057
3058         if (!mutex_trylock(&head->mutex)) {
3059                 atomic_inc(&head->node.refs);
3060                 spin_unlock(&delayed_refs->lock);
3061
3062                 btrfs_release_path(path);
3063
3064                 /*
3065                  * Mutex was contended, block until it's released and let
3066                  * caller try again
3067                  */
3068                 mutex_lock(&head->mutex);
3069                 mutex_unlock(&head->mutex);
3070                 btrfs_put_delayed_ref(&head->node);
3071                 return -EAGAIN;
3072         }
3073         spin_unlock(&delayed_refs->lock);
3074
3075         spin_lock(&head->lock);
3076         list_for_each_entry(ref, &head->ref_list, list) {
3077                 /* If it's a shared ref we know a cross reference exists */
3078                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3079                         ret = 1;
3080                         break;
3081                 }
3082
3083                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3084
3085                 /*
3086                  * If our ref doesn't match the one we're currently looking at
3087                  * then we have a cross reference.
3088                  */
3089                 if (data_ref->root != root->root_key.objectid ||
3090                     data_ref->objectid != objectid ||
3091                     data_ref->offset != offset) {
3092                         ret = 1;
3093                         break;
3094                 }
3095         }
3096         spin_unlock(&head->lock);
3097         mutex_unlock(&head->mutex);
3098         return ret;
3099 }
3100
3101 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
3102                                         struct btrfs_root *root,
3103                                         struct btrfs_path *path,
3104                                         u64 objectid, u64 offset, u64 bytenr)
3105 {
3106         struct btrfs_root *extent_root = root->fs_info->extent_root;
3107         struct extent_buffer *leaf;
3108         struct btrfs_extent_data_ref *ref;
3109         struct btrfs_extent_inline_ref *iref;
3110         struct btrfs_extent_item *ei;
3111         struct btrfs_key key;
3112         u32 item_size;
3113         int ret;
3114
3115         key.objectid = bytenr;
3116         key.offset = (u64)-1;
3117         key.type = BTRFS_EXTENT_ITEM_KEY;
3118
3119         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3120         if (ret < 0)
3121                 goto out;
3122         BUG_ON(ret == 0); /* Corruption */
3123
3124         ret = -ENOENT;
3125         if (path->slots[0] == 0)
3126                 goto out;
3127
3128         path->slots[0]--;
3129         leaf = path->nodes[0];
3130         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3131
3132         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3133                 goto out;
3134
3135         ret = 1;
3136         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3137 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3138         if (item_size < sizeof(*ei)) {
3139                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3140                 goto out;
3141         }
3142 #endif
3143         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3144
3145         if (item_size != sizeof(*ei) +
3146             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3147                 goto out;
3148
3149         if (btrfs_extent_generation(leaf, ei) <=
3150             btrfs_root_last_snapshot(&root->root_item))
3151                 goto out;
3152
3153         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3154         if (btrfs_extent_inline_ref_type(leaf, iref) !=
3155             BTRFS_EXTENT_DATA_REF_KEY)
3156                 goto out;
3157
3158         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3159         if (btrfs_extent_refs(leaf, ei) !=
3160             btrfs_extent_data_ref_count(leaf, ref) ||
3161             btrfs_extent_data_ref_root(leaf, ref) !=
3162             root->root_key.objectid ||
3163             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3164             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3165                 goto out;
3166
3167         ret = 0;
3168 out:
3169         return ret;
3170 }
3171
3172 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3173                           struct btrfs_root *root,
3174                           u64 objectid, u64 offset, u64 bytenr)
3175 {
3176         struct btrfs_path *path;
3177         int ret;
3178         int ret2;
3179
3180         path = btrfs_alloc_path();
3181         if (!path)
3182                 return -ENOENT;
3183
3184         do {
3185                 ret = check_committed_ref(trans, root, path, objectid,
3186                                           offset, bytenr);
3187                 if (ret && ret != -ENOENT)
3188                         goto out;
3189
3190                 ret2 = check_delayed_ref(trans, root, path, objectid,
3191                                          offset, bytenr);
3192         } while (ret2 == -EAGAIN);
3193
3194         if (ret2 && ret2 != -ENOENT) {
3195                 ret = ret2;
3196                 goto out;
3197         }
3198
3199         if (ret != -ENOENT || ret2 != -ENOENT)
3200                 ret = 0;
3201 out:
3202         btrfs_free_path(path);
3203         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3204                 WARN_ON(ret > 0);
3205         return ret;
3206 }
3207
3208 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3209                            struct btrfs_root *root,
3210                            struct extent_buffer *buf,
3211                            int full_backref, int inc)
3212 {
3213         u64 bytenr;
3214         u64 num_bytes;
3215         u64 parent;
3216         u64 ref_root;
3217         u32 nritems;
3218         struct btrfs_key key;
3219         struct btrfs_file_extent_item *fi;
3220         int i;
3221         int level;
3222         int ret = 0;
3223         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3224                             u64, u64, u64, u64, u64, u64);
3225
3226
3227         if (btrfs_test_is_dummy_root(root))
3228                 return 0;
3229
3230         ref_root = btrfs_header_owner(buf);
3231         nritems = btrfs_header_nritems(buf);
3232         level = btrfs_header_level(buf);
3233
3234         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3235                 return 0;
3236
3237         if (inc)
3238                 process_func = btrfs_inc_extent_ref;
3239         else
3240                 process_func = btrfs_free_extent;
3241
3242         if (full_backref)
3243                 parent = buf->start;
3244         else
3245                 parent = 0;
3246
3247         for (i = 0; i < nritems; i++) {
3248                 if (level == 0) {
3249                         btrfs_item_key_to_cpu(buf, &key, i);
3250                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3251                                 continue;
3252                         fi = btrfs_item_ptr(buf, i,
3253                                             struct btrfs_file_extent_item);
3254                         if (btrfs_file_extent_type(buf, fi) ==
3255                             BTRFS_FILE_EXTENT_INLINE)
3256                                 continue;
3257                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3258                         if (bytenr == 0)
3259                                 continue;
3260
3261                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3262                         key.offset -= btrfs_file_extent_offset(buf, fi);
3263                         ret = process_func(trans, root, bytenr, num_bytes,
3264                                            parent, ref_root, key.objectid,
3265                                            key.offset);
3266                         if (ret)
3267                                 goto fail;
3268                 } else {
3269                         bytenr = btrfs_node_blockptr(buf, i);
3270                         num_bytes = root->nodesize;
3271                         ret = process_func(trans, root, bytenr, num_bytes,
3272                                            parent, ref_root, level - 1, 0);
3273                         if (ret)
3274                                 goto fail;
3275                 }
3276         }
3277         return 0;
3278 fail:
3279         return ret;
3280 }
3281
3282 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3283                   struct extent_buffer *buf, int full_backref)
3284 {
3285         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3286 }
3287
3288 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3289                   struct extent_buffer *buf, int full_backref)
3290 {
3291         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3292 }
3293
3294 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3295                                  struct btrfs_root *root,
3296                                  struct btrfs_path *path,
3297                                  struct btrfs_block_group_cache *cache)
3298 {
3299         int ret;
3300         struct btrfs_root *extent_root = root->fs_info->extent_root;
3301         unsigned long bi;
3302         struct extent_buffer *leaf;
3303
3304         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3305         if (ret) {
3306                 if (ret > 0)
3307                         ret = -ENOENT;
3308                 goto fail;
3309         }
3310
3311         leaf = path->nodes[0];
3312         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3313         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3314         btrfs_mark_buffer_dirty(leaf);
3315 fail:
3316         btrfs_release_path(path);
3317         return ret;
3318
3319 }
3320
3321 static struct btrfs_block_group_cache *
3322 next_block_group(struct btrfs_root *root,
3323                  struct btrfs_block_group_cache *cache)
3324 {
3325         struct rb_node *node;
3326
3327         spin_lock(&root->fs_info->block_group_cache_lock);
3328
3329         /* If our block group was removed, we need a full search. */
3330         if (RB_EMPTY_NODE(&cache->cache_node)) {
3331                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3332
3333                 spin_unlock(&root->fs_info->block_group_cache_lock);
3334                 btrfs_put_block_group(cache);
3335                 cache = btrfs_lookup_first_block_group(root->fs_info,
3336                                                        next_bytenr);
3337                 return cache;
3338         }
3339         node = rb_next(&cache->cache_node);
3340         btrfs_put_block_group(cache);
3341         if (node) {
3342                 cache = rb_entry(node, struct btrfs_block_group_cache,
3343                                  cache_node);
3344                 btrfs_get_block_group(cache);
3345         } else
3346                 cache = NULL;
3347         spin_unlock(&root->fs_info->block_group_cache_lock);
3348         return cache;
3349 }
3350
3351 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3352                             struct btrfs_trans_handle *trans,
3353                             struct btrfs_path *path)
3354 {
3355         struct btrfs_root *root = block_group->fs_info->tree_root;
3356         struct inode *inode = NULL;
3357         u64 alloc_hint = 0;
3358         int dcs = BTRFS_DC_ERROR;
3359         u64 num_pages = 0;
3360         int retries = 0;
3361         int ret = 0;
3362
3363         /*
3364          * If this block group is smaller than 100 megs don't bother caching the
3365          * block group.
3366          */
3367         if (block_group->key.offset < (100 * SZ_1M)) {
3368                 spin_lock(&block_group->lock);
3369                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3370                 spin_unlock(&block_group->lock);
3371                 return 0;
3372         }
3373
3374         if (trans->aborted)
3375                 return 0;
3376 again:
3377         inode = lookup_free_space_inode(root, block_group, path);
3378         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3379                 ret = PTR_ERR(inode);
3380                 btrfs_release_path(path);
3381                 goto out;
3382         }
3383
3384         if (IS_ERR(inode)) {
3385                 BUG_ON(retries);
3386                 retries++;
3387
3388                 if (block_group->ro)
3389                         goto out_free;
3390
3391                 ret = create_free_space_inode(root, trans, block_group, path);
3392                 if (ret)
3393                         goto out_free;
3394                 goto again;
3395         }
3396
3397         /* We've already setup this transaction, go ahead and exit */
3398         if (block_group->cache_generation == trans->transid &&
3399             i_size_read(inode)) {
3400                 dcs = BTRFS_DC_SETUP;
3401                 goto out_put;
3402         }
3403
3404         /*
3405          * We want to set the generation to 0, that way if anything goes wrong
3406          * from here on out we know not to trust this cache when we load up next
3407          * time.
3408          */
3409         BTRFS_I(inode)->generation = 0;
3410         ret = btrfs_update_inode(trans, root, inode);
3411         if (ret) {
3412                 /*
3413                  * So theoretically we could recover from this, simply set the
3414                  * super cache generation to 0 so we know to invalidate the
3415                  * cache, but then we'd have to keep track of the block groups
3416                  * that fail this way so we know we _have_ to reset this cache
3417                  * before the next commit or risk reading stale cache.  So to
3418                  * limit our exposure to horrible edge cases lets just abort the
3419                  * transaction, this only happens in really bad situations
3420                  * anyway.
3421                  */
3422                 btrfs_abort_transaction(trans, root, ret);
3423                 goto out_put;
3424         }
3425         WARN_ON(ret);
3426
3427         if (i_size_read(inode) > 0) {
3428                 ret = btrfs_check_trunc_cache_free_space(root,
3429                                         &root->fs_info->global_block_rsv);
3430                 if (ret)
3431                         goto out_put;
3432
3433                 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3434                 if (ret)
3435                         goto out_put;
3436         }
3437
3438         spin_lock(&block_group->lock);
3439         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3440             !btrfs_test_opt(root, SPACE_CACHE)) {
3441                 /*
3442                  * don't bother trying to write stuff out _if_
3443                  * a) we're not cached,
3444                  * b) we're with nospace_cache mount option.
3445                  */
3446                 dcs = BTRFS_DC_WRITTEN;
3447                 spin_unlock(&block_group->lock);
3448                 goto out_put;
3449         }
3450         spin_unlock(&block_group->lock);
3451
3452         /*
3453          * We hit an ENOSPC when setting up the cache in this transaction, just
3454          * skip doing the setup, we've already cleared the cache so we're safe.
3455          */
3456         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3457                 ret = -ENOSPC;
3458                 goto out_put;
3459         }
3460
3461         /*
3462          * Try to preallocate enough space based on how big the block group is.
3463          * Keep in mind this has to include any pinned space which could end up
3464          * taking up quite a bit since it's not folded into the other space
3465          * cache.
3466          */
3467         num_pages = div_u64(block_group->key.offset, SZ_256M);
3468         if (!num_pages)
3469                 num_pages = 1;
3470
3471         num_pages *= 16;
3472         num_pages *= PAGE_SIZE;
3473
3474         ret = btrfs_check_data_free_space(inode, 0, num_pages);
3475         if (ret)
3476                 goto out_put;
3477
3478         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3479                                               num_pages, num_pages,
3480                                               &alloc_hint);
3481         /*
3482          * Our cache requires contiguous chunks so that we don't modify a bunch
3483          * of metadata or split extents when writing the cache out, which means
3484          * we can enospc if we are heavily fragmented in addition to just normal
3485          * out of space conditions.  So if we hit this just skip setting up any
3486          * other block groups for this transaction, maybe we'll unpin enough
3487          * space the next time around.
3488          */
3489         if (!ret)
3490                 dcs = BTRFS_DC_SETUP;
3491         else if (ret == -ENOSPC)
3492                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3493         btrfs_free_reserved_data_space(inode, 0, num_pages);
3494
3495 out_put:
3496         iput(inode);
3497 out_free:
3498         btrfs_release_path(path);
3499 out:
3500         spin_lock(&block_group->lock);
3501         if (!ret && dcs == BTRFS_DC_SETUP)
3502                 block_group->cache_generation = trans->transid;
3503         block_group->disk_cache_state = dcs;
3504         spin_unlock(&block_group->lock);
3505
3506         return ret;
3507 }
3508
3509 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3510                             struct btrfs_root *root)
3511 {
3512         struct btrfs_block_group_cache *cache, *tmp;
3513         struct btrfs_transaction *cur_trans = trans->transaction;
3514         struct btrfs_path *path;
3515
3516         if (list_empty(&cur_trans->dirty_bgs) ||
3517             !btrfs_test_opt(root, SPACE_CACHE))
3518                 return 0;
3519
3520         path = btrfs_alloc_path();
3521         if (!path)
3522                 return -ENOMEM;
3523
3524         /* Could add new block groups, use _safe just in case */
3525         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3526                                  dirty_list) {
3527                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3528                         cache_save_setup(cache, trans, path);
3529         }
3530
3531         btrfs_free_path(path);
3532         return 0;
3533 }
3534
3535 /*
3536  * transaction commit does final block group cache writeback during a
3537  * critical section where nothing is allowed to change the FS.  This is
3538  * required in order for the cache to actually match the block group,
3539  * but can introduce a lot of latency into the commit.
3540  *
3541  * So, btrfs_start_dirty_block_groups is here to kick off block group
3542  * cache IO.  There's a chance we'll have to redo some of it if the
3543  * block group changes again during the commit, but it greatly reduces
3544  * the commit latency by getting rid of the easy block groups while
3545  * we're still allowing others to join the commit.
3546  */
3547 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3548                                    struct btrfs_root *root)
3549 {
3550         struct btrfs_block_group_cache *cache;
3551         struct btrfs_transaction *cur_trans = trans->transaction;
3552         int ret = 0;
3553         int should_put;
3554         struct btrfs_path *path = NULL;
3555         LIST_HEAD(dirty);
3556         struct list_head *io = &cur_trans->io_bgs;
3557         int num_started = 0;
3558         int loops = 0;
3559
3560         spin_lock(&cur_trans->dirty_bgs_lock);
3561         if (list_empty(&cur_trans->dirty_bgs)) {
3562                 spin_unlock(&cur_trans->dirty_bgs_lock);
3563                 return 0;
3564         }
3565         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3566         spin_unlock(&cur_trans->dirty_bgs_lock);
3567
3568 again:
3569         /*
3570          * make sure all the block groups on our dirty list actually
3571          * exist
3572          */
3573         btrfs_create_pending_block_groups(trans, root);
3574
3575         if (!path) {
3576                 path = btrfs_alloc_path();
3577                 if (!path)
3578                         return -ENOMEM;
3579         }
3580
3581         /*
3582          * cache_write_mutex is here only to save us from balance or automatic
3583          * removal of empty block groups deleting this block group while we are
3584          * writing out the cache
3585          */
3586         mutex_lock(&trans->transaction->cache_write_mutex);
3587         while (!list_empty(&dirty)) {
3588                 cache = list_first_entry(&dirty,
3589                                          struct btrfs_block_group_cache,
3590                                          dirty_list);
3591                 /*
3592                  * this can happen if something re-dirties a block
3593                  * group that is already under IO.  Just wait for it to
3594                  * finish and then do it all again
3595                  */
3596                 if (!list_empty(&cache->io_list)) {
3597                         list_del_init(&cache->io_list);
3598                         btrfs_wait_cache_io(root, trans, cache,
3599                                             &cache->io_ctl, path,
3600                                             cache->key.objectid);
3601                         btrfs_put_block_group(cache);
3602                 }
3603
3604
3605                 /*
3606                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3607                  * if it should update the cache_state.  Don't delete
3608                  * until after we wait.
3609                  *
3610                  * Since we're not running in the commit critical section
3611                  * we need the dirty_bgs_lock to protect from update_block_group
3612                  */
3613                 spin_lock(&cur_trans->dirty_bgs_lock);
3614                 list_del_init(&cache->dirty_list);
3615                 spin_unlock(&cur_trans->dirty_bgs_lock);
3616
3617                 should_put = 1;
3618
3619                 cache_save_setup(cache, trans, path);
3620
3621                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3622                         cache->io_ctl.inode = NULL;
3623                         ret = btrfs_write_out_cache(root, trans, cache, path);
3624                         if (ret == 0 && cache->io_ctl.inode) {
3625                                 num_started++;
3626                                 should_put = 0;
3627
3628                                 /*
3629                                  * the cache_write_mutex is protecting
3630                                  * the io_list
3631                                  */
3632                                 list_add_tail(&cache->io_list, io);
3633                         } else {
3634                                 /*
3635                                  * if we failed to write the cache, the
3636                                  * generation will be bad and life goes on
3637                                  */
3638                                 ret = 0;
3639                         }
3640                 }
3641                 if (!ret) {
3642                         ret = write_one_cache_group(trans, root, path, cache);
3643                         /*
3644                          * Our block group might still be attached to the list
3645                          * of new block groups in the transaction handle of some
3646                          * other task (struct btrfs_trans_handle->new_bgs). This
3647                          * means its block group item isn't yet in the extent
3648                          * tree. If this happens ignore the error, as we will
3649                          * try again later in the critical section of the
3650                          * transaction commit.
3651                          */
3652                         if (ret == -ENOENT) {
3653                                 ret = 0;
3654                                 spin_lock(&cur_trans->dirty_bgs_lock);
3655                                 if (list_empty(&cache->dirty_list)) {
3656                                         list_add_tail(&cache->dirty_list,
3657                                                       &cur_trans->dirty_bgs);
3658                                         btrfs_get_block_group(cache);
3659                                 }
3660                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3661                         } else if (ret) {
3662                                 btrfs_abort_transaction(trans, root, ret);
3663                         }
3664                 }
3665
3666                 /* if its not on the io list, we need to put the block group */
3667                 if (should_put)
3668                         btrfs_put_block_group(cache);
3669
3670                 if (ret)
3671                         break;
3672
3673                 /*
3674                  * Avoid blocking other tasks for too long. It might even save
3675                  * us from writing caches for block groups that are going to be
3676                  * removed.
3677                  */
3678                 mutex_unlock(&trans->transaction->cache_write_mutex);
3679                 mutex_lock(&trans->transaction->cache_write_mutex);
3680         }
3681         mutex_unlock(&trans->transaction->cache_write_mutex);
3682
3683         /*
3684          * go through delayed refs for all the stuff we've just kicked off
3685          * and then loop back (just once)
3686          */
3687         ret = btrfs_run_delayed_refs(trans, root, 0);
3688         if (!ret && loops == 0) {
3689                 loops++;
3690                 spin_lock(&cur_trans->dirty_bgs_lock);
3691                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3692                 /*
3693                  * dirty_bgs_lock protects us from concurrent block group
3694                  * deletes too (not just cache_write_mutex).
3695                  */
3696                 if (!list_empty(&dirty)) {
3697                         spin_unlock(&cur_trans->dirty_bgs_lock);
3698                         goto again;
3699                 }
3700                 spin_unlock(&cur_trans->dirty_bgs_lock);
3701         }
3702
3703         btrfs_free_path(path);
3704         return ret;
3705 }
3706
3707 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3708                                    struct btrfs_root *root)
3709 {
3710         struct btrfs_block_group_cache *cache;
3711         struct btrfs_transaction *cur_trans = trans->transaction;
3712         int ret = 0;
3713         int should_put;
3714         struct btrfs_path *path;
3715         struct list_head *io = &cur_trans->io_bgs;
3716         int num_started = 0;
3717
3718         path = btrfs_alloc_path();
3719         if (!path)
3720                 return -ENOMEM;
3721
3722         /*
3723          * Even though we are in the critical section of the transaction commit,
3724          * we can still have concurrent tasks adding elements to this
3725          * transaction's list of dirty block groups. These tasks correspond to
3726          * endio free space workers started when writeback finishes for a
3727          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3728          * allocate new block groups as a result of COWing nodes of the root
3729          * tree when updating the free space inode. The writeback for the space
3730          * caches is triggered by an earlier call to
3731          * btrfs_start_dirty_block_groups() and iterations of the following
3732          * loop.
3733          * Also we want to do the cache_save_setup first and then run the
3734          * delayed refs to make sure we have the best chance at doing this all
3735          * in one shot.
3736          */
3737         spin_lock(&cur_trans->dirty_bgs_lock);
3738         while (!list_empty(&cur_trans->dirty_bgs)) {
3739                 cache = list_first_entry(&cur_trans->dirty_bgs,
3740                                          struct btrfs_block_group_cache,
3741                                          dirty_list);
3742
3743                 /*
3744                  * this can happen if cache_save_setup re-dirties a block
3745                  * group that is already under IO.  Just wait for it to
3746                  * finish and then do it all again
3747                  */
3748                 if (!list_empty(&cache->io_list)) {
3749                         spin_unlock(&cur_trans->dirty_bgs_lock);
3750                         list_del_init(&cache->io_list);
3751                         btrfs_wait_cache_io(root, trans, cache,
3752                                             &cache->io_ctl, path,
3753                                             cache->key.objectid);
3754                         btrfs_put_block_group(cache);
3755                         spin_lock(&cur_trans->dirty_bgs_lock);
3756                 }
3757
3758                 /*
3759                  * don't remove from the dirty list until after we've waited
3760                  * on any pending IO
3761                  */
3762                 list_del_init(&cache->dirty_list);
3763                 spin_unlock(&cur_trans->dirty_bgs_lock);
3764                 should_put = 1;
3765
3766                 cache_save_setup(cache, trans, path);
3767
3768                 if (!ret)
3769                         ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3770
3771                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3772                         cache->io_ctl.inode = NULL;
3773                         ret = btrfs_write_out_cache(root, trans, cache, path);
3774                         if (ret == 0 && cache->io_ctl.inode) {
3775                                 num_started++;
3776                                 should_put = 0;
3777                                 list_add_tail(&cache->io_list, io);
3778                         } else {
3779                                 /*
3780                                  * if we failed to write the cache, the
3781                                  * generation will be bad and life goes on
3782                                  */
3783                                 ret = 0;
3784                         }
3785                 }
3786                 if (!ret) {
3787                         ret = write_one_cache_group(trans, root, path, cache);
3788                         /*
3789                          * One of the free space endio workers might have
3790                          * created a new block group while updating a free space
3791                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3792                          * and hasn't released its transaction handle yet, in
3793                          * which case the new block group is still attached to
3794                          * its transaction handle and its creation has not
3795                          * finished yet (no block group item in the extent tree
3796                          * yet, etc). If this is the case, wait for all free
3797                          * space endio workers to finish and retry. This is a
3798                          * a very rare case so no need for a more efficient and
3799                          * complex approach.
3800                          */
3801                         if (ret == -ENOENT) {
3802                                 wait_event(cur_trans->writer_wait,
3803                                    atomic_read(&cur_trans->num_writers) == 1);
3804                                 ret = write_one_cache_group(trans, root, path,
3805                                                             cache);
3806                         }
3807                         if (ret)
3808                                 btrfs_abort_transaction(trans, root, ret);
3809                 }
3810
3811                 /* if its not on the io list, we need to put the block group */
3812                 if (should_put)
3813                         btrfs_put_block_group(cache);
3814                 spin_lock(&cur_trans->dirty_bgs_lock);
3815         }
3816         spin_unlock(&cur_trans->dirty_bgs_lock);
3817
3818         while (!list_empty(io)) {
3819                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3820                                          io_list);
3821                 list_del_init(&cache->io_list);
3822                 btrfs_wait_cache_io(root, trans, cache,
3823                                     &cache->io_ctl, path, cache->key.objectid);
3824                 btrfs_put_block_group(cache);
3825         }
3826
3827         btrfs_free_path(path);
3828         return ret;
3829 }
3830
3831 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3832 {
3833         struct btrfs_block_group_cache *block_group;
3834         int readonly = 0;
3835
3836         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3837         if (!block_group || block_group->ro)
3838                 readonly = 1;
3839         if (block_group)
3840                 btrfs_put_block_group(block_group);
3841         return readonly;
3842 }
3843
3844 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3845 {
3846         struct btrfs_block_group_cache *bg;
3847         bool ret = true;
3848
3849         bg = btrfs_lookup_block_group(fs_info, bytenr);
3850         if (!bg)
3851                 return false;
3852
3853         spin_lock(&bg->lock);
3854         if (bg->ro)
3855                 ret = false;
3856         else
3857                 atomic_inc(&bg->nocow_writers);
3858         spin_unlock(&bg->lock);
3859
3860         /* no put on block group, done by btrfs_dec_nocow_writers */
3861         if (!ret)
3862                 btrfs_put_block_group(bg);
3863
3864         return ret;
3865
3866 }
3867
3868 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3869 {
3870         struct btrfs_block_group_cache *bg;
3871
3872         bg = btrfs_lookup_block_group(fs_info, bytenr);
3873         ASSERT(bg);
3874         if (atomic_dec_and_test(&bg->nocow_writers))
3875                 wake_up_atomic_t(&bg->nocow_writers);
3876         /*
3877          * Once for our lookup and once for the lookup done by a previous call
3878          * to btrfs_inc_nocow_writers()
3879          */
3880         btrfs_put_block_group(bg);
3881         btrfs_put_block_group(bg);
3882 }
3883
3884 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
3885 {
3886         schedule();
3887         return 0;
3888 }
3889
3890 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3891 {
3892         wait_on_atomic_t(&bg->nocow_writers,
3893                          btrfs_wait_nocow_writers_atomic_t,
3894                          TASK_UNINTERRUPTIBLE);
3895 }
3896
3897 static const char *alloc_name(u64 flags)
3898 {
3899         switch (flags) {
3900         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3901                 return "mixed";
3902         case BTRFS_BLOCK_GROUP_METADATA:
3903                 return "metadata";
3904         case BTRFS_BLOCK_GROUP_DATA:
3905                 return "data";
3906         case BTRFS_BLOCK_GROUP_SYSTEM:
3907                 return "system";
3908         default:
3909                 WARN_ON(1);
3910                 return "invalid-combination";
3911         };
3912 }
3913
3914 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3915                              u64 total_bytes, u64 bytes_used,
3916                              struct btrfs_space_info **space_info)
3917 {
3918         struct btrfs_space_info *found;
3919         int i;
3920         int factor;
3921         int ret;
3922
3923         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3924                      BTRFS_BLOCK_GROUP_RAID10))
3925                 factor = 2;
3926         else
3927                 factor = 1;
3928
3929         found = __find_space_info(info, flags);
3930         if (found) {
3931                 spin_lock(&found->lock);
3932                 found->total_bytes += total_bytes;
3933                 found->disk_total += total_bytes * factor;
3934                 found->bytes_used += bytes_used;
3935                 found->disk_used += bytes_used * factor;
3936                 if (total_bytes > 0)
3937                         found->full = 0;
3938                 spin_unlock(&found->lock);
3939                 *space_info = found;
3940                 return 0;
3941         }
3942         found = kzalloc(sizeof(*found), GFP_NOFS);
3943         if (!found)
3944                 return -ENOMEM;
3945
3946         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3947         if (ret) {
3948                 kfree(found);
3949                 return ret;
3950         }
3951
3952         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3953                 INIT_LIST_HEAD(&found->block_groups[i]);
3954         init_rwsem(&found->groups_sem);
3955         spin_lock_init(&found->lock);
3956         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3957         found->total_bytes = total_bytes;
3958         found->disk_total = total_bytes * factor;
3959         found->bytes_used = bytes_used;
3960         found->disk_used = bytes_used * factor;
3961         found->bytes_pinned = 0;
3962         found->bytes_reserved = 0;
3963         found->bytes_readonly = 0;
3964         found->bytes_may_use = 0;
3965         found->full = 0;
3966         found->max_extent_size = 0;
3967         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3968         found->chunk_alloc = 0;
3969         found->flush = 0;
3970         init_waitqueue_head(&found->wait);
3971         INIT_LIST_HEAD(&found->ro_bgs);
3972
3973         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3974                                     info->space_info_kobj, "%s",
3975                                     alloc_name(found->flags));
3976         if (ret) {
3977                 kfree(found);
3978                 return ret;
3979         }
3980
3981         *space_info = found;
3982         list_add_rcu(&found->list, &info->space_info);
3983         if (flags & BTRFS_BLOCK_GROUP_DATA)
3984                 info->data_sinfo = found;
3985
3986         return ret;
3987 }
3988
3989 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3990 {
3991         u64 extra_flags = chunk_to_extended(flags) &
3992                                 BTRFS_EXTENDED_PROFILE_MASK;
3993
3994         write_seqlock(&fs_info->profiles_lock);
3995         if (flags & BTRFS_BLOCK_GROUP_DATA)
3996                 fs_info->avail_data_alloc_bits |= extra_flags;
3997         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3998                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3999         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4000                 fs_info->avail_system_alloc_bits |= extra_flags;
4001         write_sequnlock(&fs_info->profiles_lock);
4002 }
4003
4004 /*
4005  * returns target flags in extended format or 0 if restripe for this
4006  * chunk_type is not in progress
4007  *
4008  * should be called with either volume_mutex or balance_lock held
4009  */
4010 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4011 {
4012         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4013         u64 target = 0;
4014
4015         if (!bctl)
4016                 return 0;
4017
4018         if (flags & BTRFS_BLOCK_GROUP_DATA &&
4019             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4020                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4021         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4022                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4023                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4024         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4025                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4026                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4027         }
4028
4029         return target;
4030 }
4031
4032 /*
4033  * @flags: available profiles in extended format (see ctree.h)
4034  *
4035  * Returns reduced profile in chunk format.  If profile changing is in
4036  * progress (either running or paused) picks the target profile (if it's
4037  * already available), otherwise falls back to plain reducing.
4038  */
4039 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
4040 {
4041         u64 num_devices = root->fs_info->fs_devices->rw_devices;
4042         u64 target;
4043         u64 raid_type;
4044         u64 allowed = 0;
4045
4046         /*
4047          * see if restripe for this chunk_type is in progress, if so
4048          * try to reduce to the target profile
4049          */
4050         spin_lock(&root->fs_info->balance_lock);
4051         target = get_restripe_target(root->fs_info, flags);
4052         if (target) {
4053                 /* pick target profile only if it's already available */
4054                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4055                         spin_unlock(&root->fs_info->balance_lock);
4056                         return extended_to_chunk(target);
4057                 }
4058         }
4059         spin_unlock(&root->fs_info->balance_lock);
4060
4061         /* First, mask out the RAID levels which aren't possible */
4062         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4063                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4064                         allowed |= btrfs_raid_group[raid_type];
4065         }
4066         allowed &= flags;
4067
4068         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4069                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4070         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4071                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4072         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4073                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4074         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4075                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4076         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4077                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4078
4079         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4080
4081         return extended_to_chunk(flags | allowed);
4082 }
4083
4084 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
4085 {
4086         unsigned seq;
4087         u64 flags;
4088
4089         do {
4090                 flags = orig_flags;
4091                 seq = read_seqbegin(&root->fs_info->profiles_lock);
4092
4093                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4094                         flags |= root->fs_info->avail_data_alloc_bits;
4095                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4096                         flags |= root->fs_info->avail_system_alloc_bits;
4097                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4098                         flags |= root->fs_info->avail_metadata_alloc_bits;
4099         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
4100
4101         return btrfs_reduce_alloc_profile(root, flags);
4102 }
4103
4104 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4105 {
4106         u64 flags;
4107         u64 ret;
4108
4109         if (data)
4110                 flags = BTRFS_BLOCK_GROUP_DATA;
4111         else if (root == root->fs_info->chunk_root)
4112                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4113         else
4114                 flags = BTRFS_BLOCK_GROUP_METADATA;
4115
4116         ret = get_alloc_profile(root, flags);
4117         return ret;
4118 }
4119
4120 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
4121 {
4122         struct btrfs_space_info *data_sinfo;
4123         struct btrfs_root *root = BTRFS_I(inode)->root;
4124         struct btrfs_fs_info *fs_info = root->fs_info;
4125         u64 used;
4126         int ret = 0;
4127         int need_commit = 2;
4128         int have_pinned_space;
4129
4130         /* make sure bytes are sectorsize aligned */
4131         bytes = ALIGN(bytes, root->sectorsize);
4132
4133         if (btrfs_is_free_space_inode(inode)) {
4134                 need_commit = 0;
4135                 ASSERT(current->journal_info);
4136         }
4137
4138         data_sinfo = fs_info->data_sinfo;
4139         if (!data_sinfo)
4140                 goto alloc;
4141
4142 again:
4143         /* make sure we have enough space to handle the data first */
4144         spin_lock(&data_sinfo->lock);
4145         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
4146                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
4147                 data_sinfo->bytes_may_use;
4148
4149         if (used + bytes > data_sinfo->total_bytes) {
4150                 struct btrfs_trans_handle *trans;
4151
4152                 /*
4153                  * if we don't have enough free bytes in this space then we need
4154                  * to alloc a new chunk.
4155                  */
4156                 if (!data_sinfo->full) {
4157                         u64 alloc_target;
4158
4159                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4160                         spin_unlock(&data_sinfo->lock);
4161 alloc:
4162                         alloc_target = btrfs_get_alloc_profile(root, 1);
4163                         /*
4164                          * It is ugly that we don't call nolock join
4165                          * transaction for the free space inode case here.
4166                          * But it is safe because we only do the data space
4167                          * reservation for the free space cache in the
4168                          * transaction context, the common join transaction
4169                          * just increase the counter of the current transaction
4170                          * handler, doesn't try to acquire the trans_lock of
4171                          * the fs.
4172                          */
4173                         trans = btrfs_join_transaction(root);
4174                         if (IS_ERR(trans))
4175                                 return PTR_ERR(trans);
4176
4177                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4178                                              alloc_target,
4179                                              CHUNK_ALLOC_NO_FORCE);
4180                         btrfs_end_transaction(trans, root);
4181                         if (ret < 0) {
4182                                 if (ret != -ENOSPC)
4183                                         return ret;
4184                                 else {
4185                                         have_pinned_space = 1;
4186                                         goto commit_trans;
4187                                 }
4188                         }
4189
4190                         if (!data_sinfo)
4191                                 data_sinfo = fs_info->data_sinfo;
4192
4193                         goto again;
4194                 }
4195
4196                 /*
4197                  * If we don't have enough pinned space to deal with this
4198                  * allocation, and no removed chunk in current transaction,
4199                  * don't bother committing the transaction.
4200                  */
4201                 have_pinned_space = percpu_counter_compare(
4202                         &data_sinfo->total_bytes_pinned,
4203                         used + bytes - data_sinfo->total_bytes);
4204                 spin_unlock(&data_sinfo->lock);
4205
4206                 /* commit the current transaction and try again */
4207 commit_trans:
4208                 if (need_commit &&
4209                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
4210                         need_commit--;
4211
4212                         if (need_commit > 0) {
4213                                 btrfs_start_delalloc_roots(fs_info, 0, -1);
4214                                 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
4215                         }
4216
4217                         trans = btrfs_join_transaction(root);
4218                         if (IS_ERR(trans))
4219                                 return PTR_ERR(trans);
4220                         if (have_pinned_space >= 0 ||
4221                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4222                                      &trans->transaction->flags) ||
4223                             need_commit > 0) {
4224                                 ret = btrfs_commit_transaction(trans, root);
4225                                 if (ret)
4226                                         return ret;
4227                                 /*
4228                                  * The cleaner kthread might still be doing iput
4229                                  * operations. Wait for it to finish so that
4230                                  * more space is released.
4231                                  */
4232                                 mutex_lock(&root->fs_info->cleaner_delayed_iput_mutex);
4233                                 mutex_unlock(&root->fs_info->cleaner_delayed_iput_mutex);
4234                                 goto again;
4235                         } else {
4236                                 btrfs_end_transaction(trans, root);
4237                         }
4238                 }
4239
4240                 trace_btrfs_space_reservation(root->fs_info,
4241                                               "space_info:enospc",
4242                                               data_sinfo->flags, bytes, 1);
4243                 return -ENOSPC;
4244         }
4245         data_sinfo->bytes_may_use += bytes;
4246         trace_btrfs_space_reservation(root->fs_info, "space_info",
4247                                       data_sinfo->flags, bytes, 1);
4248         spin_unlock(&data_sinfo->lock);
4249
4250         return ret;
4251 }
4252
4253 /*
4254  * New check_data_free_space() with ability for precious data reservation
4255  * Will replace old btrfs_check_data_free_space(), but for patch split,
4256  * add a new function first and then replace it.
4257  */
4258 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4259 {
4260         struct btrfs_root *root = BTRFS_I(inode)->root;
4261         int ret;
4262
4263         /* align the range */
4264         len = round_up(start + len, root->sectorsize) -
4265               round_down(start, root->sectorsize);
4266         start = round_down(start, root->sectorsize);
4267
4268         ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4269         if (ret < 0)
4270                 return ret;
4271
4272         /*
4273          * Use new btrfs_qgroup_reserve_data to reserve precious data space
4274          *
4275          * TODO: Find a good method to avoid reserve data space for NOCOW
4276          * range, but don't impact performance on quota disable case.
4277          */
4278         ret = btrfs_qgroup_reserve_data(inode, start, len);
4279         return ret;
4280 }
4281
4282 /*
4283  * Called if we need to clear a data reservation for this inode
4284  * Normally in a error case.
4285  *
4286  * This one will *NOT* use accurate qgroup reserved space API, just for case
4287  * which we can't sleep and is sure it won't affect qgroup reserved space.
4288  * Like clear_bit_hook().
4289  */
4290 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4291                                             u64 len)
4292 {
4293         struct btrfs_root *root = BTRFS_I(inode)->root;
4294         struct btrfs_space_info *data_sinfo;
4295
4296         /* Make sure the range is aligned to sectorsize */
4297         len = round_up(start + len, root->sectorsize) -
4298               round_down(start, root->sectorsize);
4299         start = round_down(start, root->sectorsize);
4300
4301         data_sinfo = root->fs_info->data_sinfo;
4302         spin_lock(&data_sinfo->lock);
4303         if (WARN_ON(data_sinfo->bytes_may_use < len))
4304                 data_sinfo->bytes_may_use = 0;
4305         else
4306                 data_sinfo->bytes_may_use -= len;
4307         trace_btrfs_space_reservation(root->fs_info, "space_info",
4308                                       data_sinfo->flags, len, 0);
4309         spin_unlock(&data_sinfo->lock);
4310 }
4311
4312 /*
4313  * Called if we need to clear a data reservation for this inode
4314  * Normally in a error case.
4315  *
4316  * This one will handle the per-inode data rsv map for accurate reserved
4317  * space framework.
4318  */
4319 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4320 {
4321         btrfs_free_reserved_data_space_noquota(inode, start, len);
4322         btrfs_qgroup_free_data(inode, start, len);
4323 }
4324
4325 static void force_metadata_allocation(struct btrfs_fs_info *info)
4326 {
4327         struct list_head *head = &info->space_info;
4328         struct btrfs_space_info *found;
4329
4330         rcu_read_lock();
4331         list_for_each_entry_rcu(found, head, list) {
4332                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4333                         found->force_alloc = CHUNK_ALLOC_FORCE;
4334         }
4335         rcu_read_unlock();
4336 }
4337
4338 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4339 {
4340         return (global->size << 1);
4341 }
4342
4343 static int should_alloc_chunk(struct btrfs_root *root,
4344                               struct btrfs_space_info *sinfo, int force)
4345 {
4346         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4347         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4348         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4349         u64 thresh;
4350
4351         if (force == CHUNK_ALLOC_FORCE)
4352                 return 1;
4353
4354         /*
4355          * We need to take into account the global rsv because for all intents
4356          * and purposes it's used space.  Don't worry about locking the
4357          * global_rsv, it doesn't change except when the transaction commits.
4358          */
4359         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4360                 num_allocated += calc_global_rsv_need_space(global_rsv);
4361
4362         /*
4363          * in limited mode, we want to have some free space up to
4364          * about 1% of the FS size.
4365          */
4366         if (force == CHUNK_ALLOC_LIMITED) {
4367                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4368                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4369
4370                 if (num_bytes - num_allocated < thresh)
4371                         return 1;
4372         }
4373
4374         if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4375                 return 0;
4376         return 1;
4377 }
4378
4379 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4380 {
4381         u64 num_dev;
4382
4383         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4384                     BTRFS_BLOCK_GROUP_RAID0 |
4385                     BTRFS_BLOCK_GROUP_RAID5 |
4386                     BTRFS_BLOCK_GROUP_RAID6))
4387                 num_dev = root->fs_info->fs_devices->rw_devices;
4388         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4389                 num_dev = 2;
4390         else
4391                 num_dev = 1;    /* DUP or single */
4392
4393         return num_dev;
4394 }
4395
4396 /*
4397  * If @is_allocation is true, reserve space in the system space info necessary
4398  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4399  * removing a chunk.
4400  */
4401 void check_system_chunk(struct btrfs_trans_handle *trans,
4402                         struct btrfs_root *root,
4403                         u64 type)
4404 {
4405         struct btrfs_space_info *info;
4406         u64 left;
4407         u64 thresh;
4408         int ret = 0;
4409         u64 num_devs;
4410
4411         /*
4412          * Needed because we can end up allocating a system chunk and for an
4413          * atomic and race free space reservation in the chunk block reserve.
4414          */
4415         ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4416
4417         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4418         spin_lock(&info->lock);
4419         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4420                 info->bytes_reserved - info->bytes_readonly -
4421                 info->bytes_may_use;
4422         spin_unlock(&info->lock);
4423
4424         num_devs = get_profile_num_devs(root, type);
4425
4426         /* num_devs device items to update and 1 chunk item to add or remove */
4427         thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4428                 btrfs_calc_trans_metadata_size(root, 1);
4429
4430         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
4431                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4432                         left, thresh, type);
4433                 dump_space_info(info, 0, 0);
4434         }
4435
4436         if (left < thresh) {
4437                 u64 flags;
4438
4439                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4440                 /*
4441                  * Ignore failure to create system chunk. We might end up not
4442                  * needing it, as we might not need to COW all nodes/leafs from
4443                  * the paths we visit in the chunk tree (they were already COWed
4444                  * or created in the current transaction for example).
4445                  */
4446                 ret = btrfs_alloc_chunk(trans, root, flags);
4447         }
4448
4449         if (!ret) {
4450                 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4451                                           &root->fs_info->chunk_block_rsv,
4452                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4453                 if (!ret)
4454                         trans->chunk_bytes_reserved += thresh;
4455         }
4456 }
4457
4458 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4459                           struct btrfs_root *extent_root, u64 flags, int force)
4460 {
4461         struct btrfs_space_info *space_info;
4462         struct btrfs_fs_info *fs_info = extent_root->fs_info;
4463         int wait_for_alloc = 0;
4464         int ret = 0;
4465
4466         /* Don't re-enter if we're already allocating a chunk */
4467         if (trans->allocating_chunk)
4468                 return -ENOSPC;
4469
4470         space_info = __find_space_info(extent_root->fs_info, flags);
4471         if (!space_info) {
4472                 ret = update_space_info(extent_root->fs_info, flags,
4473                                         0, 0, &space_info);
4474                 BUG_ON(ret); /* -ENOMEM */
4475         }
4476         BUG_ON(!space_info); /* Logic error */
4477
4478 again:
4479         spin_lock(&space_info->lock);
4480         if (force < space_info->force_alloc)
4481                 force = space_info->force_alloc;
4482         if (space_info->full) {
4483                 if (should_alloc_chunk(extent_root, space_info, force))
4484                         ret = -ENOSPC;
4485                 else
4486                         ret = 0;
4487                 spin_unlock(&space_info->lock);
4488                 return ret;
4489         }
4490
4491         if (!should_alloc_chunk(extent_root, space_info, force)) {
4492                 spin_unlock(&space_info->lock);
4493                 return 0;
4494         } else if (space_info->chunk_alloc) {
4495                 wait_for_alloc = 1;
4496         } else {
4497                 space_info->chunk_alloc = 1;
4498         }
4499
4500         spin_unlock(&space_info->lock);
4501
4502         mutex_lock(&fs_info->chunk_mutex);
4503
4504         /*
4505          * The chunk_mutex is held throughout the entirety of a chunk
4506          * allocation, so once we've acquired the chunk_mutex we know that the
4507          * other guy is done and we need to recheck and see if we should
4508          * allocate.
4509          */
4510         if (wait_for_alloc) {
4511                 mutex_unlock(&fs_info->chunk_mutex);
4512                 wait_for_alloc = 0;
4513                 goto again;
4514         }
4515
4516         trans->allocating_chunk = true;
4517
4518         /*
4519          * If we have mixed data/metadata chunks we want to make sure we keep
4520          * allocating mixed chunks instead of individual chunks.
4521          */
4522         if (btrfs_mixed_space_info(space_info))
4523                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4524
4525         /*
4526          * if we're doing a data chunk, go ahead and make sure that
4527          * we keep a reasonable number of metadata chunks allocated in the
4528          * FS as well.
4529          */
4530         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4531                 fs_info->data_chunk_allocations++;
4532                 if (!(fs_info->data_chunk_allocations %
4533                       fs_info->metadata_ratio))
4534                         force_metadata_allocation(fs_info);
4535         }
4536
4537         /*
4538          * Check if we have enough space in SYSTEM chunk because we may need
4539          * to update devices.
4540          */
4541         check_system_chunk(trans, extent_root, flags);
4542
4543         ret = btrfs_alloc_chunk(trans, extent_root, flags);
4544         trans->allocating_chunk = false;
4545
4546         spin_lock(&space_info->lock);
4547         if (ret < 0 && ret != -ENOSPC)
4548                 goto out;
4549         if (ret)
4550                 space_info->full = 1;
4551         else
4552                 ret = 1;
4553
4554         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4555 out:
4556         space_info->chunk_alloc = 0;
4557         spin_unlock(&space_info->lock);
4558         mutex_unlock(&fs_info->chunk_mutex);
4559         /*
4560          * When we allocate a new chunk we reserve space in the chunk block
4561          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4562          * add new nodes/leafs to it if we end up needing to do it when
4563          * inserting the chunk item and updating device items as part of the
4564          * second phase of chunk allocation, performed by
4565          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4566          * large number of new block groups to create in our transaction
4567          * handle's new_bgs list to avoid exhausting the chunk block reserve
4568          * in extreme cases - like having a single transaction create many new
4569          * block groups when starting to write out the free space caches of all
4570          * the block groups that were made dirty during the lifetime of the
4571          * transaction.
4572          */
4573         if (trans->can_flush_pending_bgs &&
4574             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4575                 btrfs_create_pending_block_groups(trans, trans->root);
4576                 btrfs_trans_release_chunk_metadata(trans);
4577         }
4578         return ret;
4579 }
4580
4581 static int can_overcommit(struct btrfs_root *root,
4582                           struct btrfs_space_info *space_info, u64 bytes,
4583                           enum btrfs_reserve_flush_enum flush)
4584 {
4585         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4586         u64 profile = btrfs_get_alloc_profile(root, 0);
4587         u64 space_size;
4588         u64 avail;
4589         u64 used;
4590
4591         used = space_info->bytes_used + space_info->bytes_reserved +
4592                 space_info->bytes_pinned + space_info->bytes_readonly;
4593
4594         /*
4595          * We only want to allow over committing if we have lots of actual space
4596          * free, but if we don't have enough space to handle the global reserve
4597          * space then we could end up having a real enospc problem when trying
4598          * to allocate a chunk or some other such important allocation.
4599          */
4600         spin_lock(&global_rsv->lock);
4601         space_size = calc_global_rsv_need_space(global_rsv);
4602         spin_unlock(&global_rsv->lock);
4603         if (used + space_size >= space_info->total_bytes)
4604                 return 0;
4605
4606         used += space_info->bytes_may_use;
4607
4608         spin_lock(&root->fs_info->free_chunk_lock);
4609         avail = root->fs_info->free_chunk_space;
4610         spin_unlock(&root->fs_info->free_chunk_lock);
4611
4612         /*
4613          * If we have dup, raid1 or raid10 then only half of the free
4614          * space is actually useable.  For raid56, the space info used
4615          * doesn't include the parity drive, so we don't have to
4616          * change the math
4617          */
4618         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4619                        BTRFS_BLOCK_GROUP_RAID1 |
4620                        BTRFS_BLOCK_GROUP_RAID10))
4621                 avail >>= 1;
4622
4623         /*
4624          * If we aren't flushing all things, let us overcommit up to
4625          * 1/2th of the space. If we can flush, don't let us overcommit
4626          * too much, let it overcommit up to 1/8 of the space.
4627          */
4628         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4629                 avail >>= 3;
4630         else
4631                 avail >>= 1;
4632
4633         if (used + bytes < space_info->total_bytes + avail)
4634                 return 1;
4635         return 0;
4636 }
4637
4638 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4639                                          unsigned long nr_pages, int nr_items)
4640 {
4641         struct super_block *sb = root->fs_info->sb;
4642
4643         if (down_read_trylock(&sb->s_umount)) {
4644                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4645                 up_read(&sb->s_umount);
4646         } else {
4647                 /*
4648                  * We needn't worry the filesystem going from r/w to r/o though
4649                  * we don't acquire ->s_umount mutex, because the filesystem
4650                  * should guarantee the delalloc inodes list be empty after
4651                  * the filesystem is readonly(all dirty pages are written to
4652                  * the disk).
4653                  */
4654                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4655                 if (!current->journal_info)
4656                         btrfs_wait_ordered_roots(root->fs_info, nr_items,
4657                                                  0, (u64)-1);
4658         }
4659 }
4660
4661 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4662 {
4663         u64 bytes;
4664         int nr;
4665
4666         bytes = btrfs_calc_trans_metadata_size(root, 1);
4667         nr = (int)div64_u64(to_reclaim, bytes);
4668         if (!nr)
4669                 nr = 1;
4670         return nr;
4671 }
4672
4673 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4674
4675 /*
4676  * shrink metadata reservation for delalloc
4677  */
4678 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4679                             bool wait_ordered)
4680 {
4681         struct btrfs_block_rsv *block_rsv;
4682         struct btrfs_space_info *space_info;
4683         struct btrfs_trans_handle *trans;
4684         u64 delalloc_bytes;
4685         u64 max_reclaim;
4686         long time_left;
4687         unsigned long nr_pages;
4688         int loops;
4689         int items;
4690         enum btrfs_reserve_flush_enum flush;
4691
4692         /* Calc the number of the pages we need flush for space reservation */
4693         items = calc_reclaim_items_nr(root, to_reclaim);
4694         to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;
4695
4696         trans = (struct btrfs_trans_handle *)current->journal_info;
4697         block_rsv = &root->fs_info->delalloc_block_rsv;
4698         space_info = block_rsv->space_info;
4699
4700         delalloc_bytes = percpu_counter_sum_positive(
4701                                                 &root->fs_info->delalloc_bytes);
4702         if (delalloc_bytes == 0) {
4703                 if (trans)
4704                         return;
4705                 if (wait_ordered)
4706                         btrfs_wait_ordered_roots(root->fs_info, items,
4707                                                  0, (u64)-1);
4708                 return;
4709         }
4710
4711         loops = 0;
4712         while (delalloc_bytes && loops < 3) {
4713                 max_reclaim = min(delalloc_bytes, to_reclaim);
4714                 nr_pages = max_reclaim >> PAGE_SHIFT;
4715                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4716                 /*
4717                  * We need to wait for the async pages to actually start before
4718                  * we do anything.
4719                  */
4720                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4721                 if (!max_reclaim)
4722                         goto skip_async;
4723
4724                 if (max_reclaim <= nr_pages)
4725                         max_reclaim = 0;
4726                 else
4727                         max_reclaim -= nr_pages;
4728
4729                 wait_event(root->fs_info->async_submit_wait,
4730                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4731                            (int)max_reclaim);
4732 skip_async:
4733                 if (!trans)
4734                         flush = BTRFS_RESERVE_FLUSH_ALL;
4735                 else
4736                         flush = BTRFS_RESERVE_NO_FLUSH;
4737                 spin_lock(&space_info->lock);
4738                 if (can_overcommit(root, space_info, orig, flush)) {
4739                         spin_unlock(&space_info->lock);
4740                         break;
4741                 }
4742                 spin_unlock(&space_info->lock);
4743
4744                 loops++;
4745                 if (wait_ordered && !trans) {
4746                         btrfs_wait_ordered_roots(root->fs_info, items,
4747                                                  0, (u64)-1);
4748                 } else {
4749                         time_left = schedule_timeout_killable(1);
4750                         if (time_left)
4751                                 break;
4752                 }
4753                 delalloc_bytes = percpu_counter_sum_positive(
4754                                                 &root->fs_info->delalloc_bytes);
4755         }
4756 }
4757
4758 /**
4759  * maybe_commit_transaction - possibly commit the transaction if its ok to
4760  * @root - the root we're allocating for
4761  * @bytes - the number of bytes we want to reserve
4762  * @force - force the commit
4763  *
4764  * This will check to make sure that committing the transaction will actually
4765  * get us somewhere and then commit the transaction if it does.  Otherwise it
4766  * will return -ENOSPC.
4767  */
4768 static int may_commit_transaction(struct btrfs_root *root,
4769                                   struct btrfs_space_info *space_info,
4770                                   u64 bytes, int force)
4771 {
4772         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4773         struct btrfs_trans_handle *trans;
4774
4775         trans = (struct btrfs_trans_handle *)current->journal_info;
4776         if (trans)
4777                 return -EAGAIN;
4778
4779         if (force)
4780                 goto commit;
4781
4782         /* See if there is enough pinned space to make this reservation */
4783         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4784                                    bytes) >= 0)
4785                 goto commit;
4786
4787         /*
4788          * See if there is some space in the delayed insertion reservation for
4789          * this reservation.
4790          */
4791         if (space_info != delayed_rsv->space_info)
4792                 return -ENOSPC;
4793
4794         spin_lock(&delayed_rsv->lock);
4795         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4796                                    bytes - delayed_rsv->size) >= 0) {
4797                 spin_unlock(&delayed_rsv->lock);
4798                 return -ENOSPC;
4799         }
4800         spin_unlock(&delayed_rsv->lock);
4801
4802 commit:
4803         trans = btrfs_join_transaction(root);
4804         if (IS_ERR(trans))
4805                 return -ENOSPC;
4806
4807         return btrfs_commit_transaction(trans, root);
4808 }
4809
4810 enum flush_state {
4811         FLUSH_DELAYED_ITEMS_NR  =       1,
4812         FLUSH_DELAYED_ITEMS     =       2,
4813         FLUSH_DELALLOC          =       3,
4814         FLUSH_DELALLOC_WAIT     =       4,
4815         ALLOC_CHUNK             =       5,
4816         COMMIT_TRANS            =       6,
4817 };
4818
4819 static int flush_space(struct btrfs_root *root,
4820                        struct btrfs_space_info *space_info, u64 num_bytes,
4821                        u64 orig_bytes, int state)
4822 {
4823         struct btrfs_trans_handle *trans;
4824         int nr;
4825         int ret = 0;
4826
4827         switch (state) {
4828         case FLUSH_DELAYED_ITEMS_NR:
4829         case FLUSH_DELAYED_ITEMS:
4830                 if (state == FLUSH_DELAYED_ITEMS_NR)
4831                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4832                 else
4833                         nr = -1;
4834
4835                 trans = btrfs_join_transaction(root);
4836                 if (IS_ERR(trans)) {
4837                         ret = PTR_ERR(trans);
4838                         break;
4839                 }
4840                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4841                 btrfs_end_transaction(trans, root);
4842                 break;
4843         case FLUSH_DELALLOC:
4844         case FLUSH_DELALLOC_WAIT:
4845                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4846                                 state == FLUSH_DELALLOC_WAIT);
4847                 break;
4848         case ALLOC_CHUNK:
4849                 trans = btrfs_join_transaction(root);
4850                 if (IS_ERR(trans)) {
4851                         ret = PTR_ERR(trans);
4852                         break;
4853                 }
4854                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4855                                      btrfs_get_alloc_profile(root, 0),
4856                                      CHUNK_ALLOC_NO_FORCE);
4857                 btrfs_end_transaction(trans, root);
4858                 if (ret == -ENOSPC)
4859                         ret = 0;
4860                 break;
4861         case COMMIT_TRANS:
4862                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4863                 break;
4864         default:
4865                 ret = -ENOSPC;
4866                 break;
4867         }
4868
4869         return ret;
4870 }
4871
4872 static inline u64
4873 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4874                                  struct btrfs_space_info *space_info)
4875 {
4876         u64 used;
4877         u64 expected;
4878         u64 to_reclaim;
4879
4880         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4881         spin_lock(&space_info->lock);
4882         if (can_overcommit(root, space_info, to_reclaim,
4883                            BTRFS_RESERVE_FLUSH_ALL)) {
4884                 to_reclaim = 0;
4885                 goto out;
4886         }
4887
4888         used = space_info->bytes_used + space_info->bytes_reserved +
4889                space_info->bytes_pinned + space_info->bytes_readonly +
4890                space_info->bytes_may_use;
4891         if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4892                 expected = div_factor_fine(space_info->total_bytes, 95);
4893         else
4894                 expected = div_factor_fine(space_info->total_bytes, 90);
4895
4896         if (used > expected)
4897                 to_reclaim = used - expected;
4898         else
4899                 to_reclaim = 0;
4900         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4901                                      space_info->bytes_reserved);
4902 out:
4903         spin_unlock(&space_info->lock);
4904
4905         return to_reclaim;
4906 }
4907
4908 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4909                                         struct btrfs_fs_info *fs_info, u64 used)
4910 {
4911         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4912
4913         /* If we're just plain full then async reclaim just slows us down. */
4914         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4915                 return 0;
4916
4917         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4918                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4919 }
4920
4921 static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info,
4922                                        struct btrfs_fs_info *fs_info,
4923                                        int flush_state)
4924 {
4925         u64 used;
4926
4927         spin_lock(&space_info->lock);
4928         /*
4929          * We run out of space and have not got any free space via flush_space,
4930          * so don't bother doing async reclaim.
4931          */
4932         if (flush_state > COMMIT_TRANS && space_info->full) {
4933                 spin_unlock(&space_info->lock);
4934                 return 0;
4935         }
4936
4937         used = space_info->bytes_used + space_info->bytes_reserved +
4938                space_info->bytes_pinned + space_info->bytes_readonly +
4939                space_info->bytes_may_use;
4940         if (need_do_async_reclaim(space_info, fs_info, used)) {
4941                 spin_unlock(&space_info->lock);
4942                 return 1;
4943         }
4944         spin_unlock(&space_info->lock);
4945
4946         return 0;
4947 }
4948
4949 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4950 {
4951         struct btrfs_fs_info *fs_info;
4952         struct btrfs_space_info *space_info;
4953         u64 to_reclaim;
4954         int flush_state;
4955
4956         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4957         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4958
4959         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4960                                                       space_info);
4961         if (!to_reclaim)
4962                 return;
4963
4964         flush_state = FLUSH_DELAYED_ITEMS_NR;
4965         do {
4966                 flush_space(fs_info->fs_root, space_info, to_reclaim,
4967                             to_reclaim, flush_state);
4968                 flush_state++;
4969                 if (!btrfs_need_do_async_reclaim(space_info, fs_info,
4970                                                  flush_state))
4971                         return;
4972         } while (flush_state < COMMIT_TRANS);
4973 }
4974
4975 void btrfs_init_async_reclaim_work(struct work_struct *work)
4976 {
4977         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
4978 }
4979
4980 /**
4981  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4982  * @root - the root we're allocating for
4983  * @block_rsv - the block_rsv we're allocating for
4984  * @orig_bytes - the number of bytes we want
4985  * @flush - whether or not we can flush to make our reservation
4986  *
4987  * This will reserve orig_bytes number of bytes from the space info associated
4988  * with the block_rsv.  If there is not enough space it will make an attempt to
4989  * flush out space to make room.  It will do this by flushing delalloc if
4990  * possible or committing the transaction.  If flush is 0 then no attempts to
4991  * regain reservations will be made and this will fail if there is not enough
4992  * space already.
4993  */
4994 static int reserve_metadata_bytes(struct btrfs_root *root,
4995                                   struct btrfs_block_rsv *block_rsv,
4996                                   u64 orig_bytes,
4997                                   enum btrfs_reserve_flush_enum flush)
4998 {
4999         struct btrfs_space_info *space_info = block_rsv->space_info;
5000         u64 used;
5001         u64 num_bytes = orig_bytes;
5002         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5003         int ret = 0;
5004         bool flushing = false;
5005
5006 again:
5007         ret = 0;
5008         spin_lock(&space_info->lock);
5009         /*
5010          * We only want to wait if somebody other than us is flushing and we
5011          * are actually allowed to flush all things.
5012          */
5013         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
5014                space_info->flush) {
5015                 spin_unlock(&space_info->lock);
5016                 /*
5017                  * If we have a trans handle we can't wait because the flusher
5018                  * may have to commit the transaction, which would mean we would
5019                  * deadlock since we are waiting for the flusher to finish, but
5020                  * hold the current transaction open.
5021                  */
5022                 if (current->journal_info)
5023                         return -EAGAIN;
5024                 ret = wait_event_killable(space_info->wait, !space_info->flush);
5025                 /* Must have been killed, return */
5026                 if (ret)
5027                         return -EINTR;
5028
5029                 spin_lock(&space_info->lock);
5030         }
5031
5032         ret = -ENOSPC;
5033         used = space_info->bytes_used + space_info->bytes_reserved +
5034                 space_info->bytes_pinned + space_info->bytes_readonly +
5035                 space_info->bytes_may_use;
5036
5037         /*
5038          * The idea here is that we've not already over-reserved the block group
5039          * then we can go ahead and save our reservation first and then start
5040          * flushing if we need to.  Otherwise if we've already overcommitted
5041          * lets start flushing stuff first and then come back and try to make
5042          * our reservation.
5043          */
5044         if (used <= space_info->total_bytes) {
5045                 if (used + orig_bytes <= space_info->total_bytes) {
5046                         space_info->bytes_may_use += orig_bytes;
5047                         trace_btrfs_space_reservation(root->fs_info,
5048                                 "space_info", space_info->flags, orig_bytes, 1);
5049                         ret = 0;
5050                 } else {
5051                         /*
5052                          * Ok set num_bytes to orig_bytes since we aren't
5053                          * overocmmitted, this way we only try and reclaim what
5054                          * we need.
5055                          */
5056                         num_bytes = orig_bytes;
5057                 }
5058         } else {
5059                 /*
5060                  * Ok we're over committed, set num_bytes to the overcommitted
5061                  * amount plus the amount of bytes that we need for this
5062                  * reservation.
5063                  */
5064                 num_bytes = used - space_info->total_bytes +
5065                         (orig_bytes * 2);
5066         }
5067
5068         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
5069                 space_info->bytes_may_use += orig_bytes;
5070                 trace_btrfs_space_reservation(root->fs_info, "space_info",
5071                                               space_info->flags, orig_bytes,
5072                                               1);
5073                 ret = 0;
5074         }
5075
5076         /*
5077          * Couldn't make our reservation, save our place so while we're trying
5078          * to reclaim space we can actually use it instead of somebody else
5079          * stealing it from us.
5080          *
5081          * We make the other tasks wait for the flush only when we can flush
5082          * all things.
5083          */
5084         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5085                 flushing = true;
5086                 space_info->flush = 1;
5087         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5088                 used += orig_bytes;
5089                 /*
5090                  * We will do the space reservation dance during log replay,
5091                  * which means we won't have fs_info->fs_root set, so don't do
5092                  * the async reclaim as we will panic.
5093                  */
5094                 if (!root->fs_info->log_root_recovering &&
5095                     need_do_async_reclaim(space_info, root->fs_info, used) &&
5096                     !work_busy(&root->fs_info->async_reclaim_work))
5097                         queue_work(system_unbound_wq,
5098                                    &root->fs_info->async_reclaim_work);
5099         }
5100         spin_unlock(&space_info->lock);
5101
5102         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5103                 goto out;
5104
5105         ret = flush_space(root, space_info, num_bytes, orig_bytes,
5106                           flush_state);
5107         flush_state++;
5108
5109         /*
5110          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
5111          * would happen. So skip delalloc flush.
5112          */
5113         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
5114             (flush_state == FLUSH_DELALLOC ||
5115              flush_state == FLUSH_DELALLOC_WAIT))
5116                 flush_state = ALLOC_CHUNK;
5117
5118         if (!ret)
5119                 goto again;
5120         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
5121                  flush_state < COMMIT_TRANS)
5122                 goto again;
5123         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
5124                  flush_state <= COMMIT_TRANS)
5125                 goto again;
5126
5127 out:
5128         if (ret == -ENOSPC &&
5129             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5130                 struct btrfs_block_rsv *global_rsv =
5131                         &root->fs_info->global_block_rsv;
5132
5133                 if (block_rsv != global_rsv &&
5134                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5135                         ret = 0;
5136         }
5137         if (ret == -ENOSPC)
5138                 trace_btrfs_space_reservation(root->fs_info,
5139                                               "space_info:enospc",
5140                                               space_info->flags, orig_bytes, 1);
5141         if (flushing) {
5142                 spin_lock(&space_info->lock);
5143                 space_info->flush = 0;
5144                 wake_up_all(&space_info->wait);
5145                 spin_unlock(&space_info->lock);
5146         }
5147         return ret;
5148 }
5149
5150 static struct btrfs_block_rsv *get_block_rsv(
5151                                         const struct btrfs_trans_handle *trans,
5152                                         const struct btrfs_root *root)
5153 {
5154         struct btrfs_block_rsv *block_rsv = NULL;
5155
5156         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5157             (root == root->fs_info->csum_root && trans->adding_csums) ||
5158              (root == root->fs_info->uuid_root))
5159                 block_rsv = trans->block_rsv;
5160
5161         if (!block_rsv)
5162                 block_rsv = root->block_rsv;
5163
5164         if (!block_rsv)
5165                 block_rsv = &root->fs_info->empty_block_rsv;
5166
5167         return block_rsv;
5168 }
5169
5170 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5171                                u64 num_bytes)
5172 {
5173         int ret = -ENOSPC;
5174         spin_lock(&block_rsv->lock);
5175         if (block_rsv->reserved >= num_bytes) {
5176                 block_rsv->reserved -= num_bytes;
5177                 if (block_rsv->reserved < block_rsv->size)
5178                         block_rsv->full = 0;
5179                 ret = 0;
5180         }
5181         spin_unlock(&block_rsv->lock);
5182         return ret;
5183 }
5184
5185 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5186                                 u64 num_bytes, int update_size)
5187 {
5188         spin_lock(&block_rsv->lock);
5189         block_rsv->reserved += num_bytes;
5190         if (update_size)
5191                 block_rsv->size += num_bytes;
5192         else if (block_rsv->reserved >= block_rsv->size)
5193                 block_rsv->full = 1;
5194         spin_unlock(&block_rsv->lock);
5195 }
5196
5197 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5198                              struct btrfs_block_rsv *dest, u64 num_bytes,
5199                              int min_factor)
5200 {
5201         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5202         u64 min_bytes;
5203
5204         if (global_rsv->space_info != dest->space_info)
5205                 return -ENOSPC;
5206
5207         spin_lock(&global_rsv->lock);
5208         min_bytes = div_factor(global_rsv->size, min_factor);
5209         if (global_rsv->reserved < min_bytes + num_bytes) {
5210                 spin_unlock(&global_rsv->lock);
5211                 return -ENOSPC;
5212         }
5213         global_rsv->reserved -= num_bytes;
5214         if (global_rsv->reserved < global_rsv->size)
5215                 global_rsv->full = 0;
5216         spin_unlock(&global_rsv->lock);
5217
5218         block_rsv_add_bytes(dest, num_bytes, 1);
5219         return 0;
5220 }
5221
5222 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5223                                     struct btrfs_block_rsv *block_rsv,
5224                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5225 {
5226         struct btrfs_space_info *space_info = block_rsv->space_info;
5227
5228         spin_lock(&block_rsv->lock);
5229         if (num_bytes == (u64)-1)
5230                 num_bytes = block_rsv->size;
5231         block_rsv->size -= num_bytes;
5232         if (block_rsv->reserved >= block_rsv->size) {
5233                 num_bytes = block_rsv->reserved - block_rsv->size;
5234                 block_rsv->reserved = block_rsv->size;
5235                 block_rsv->full = 1;
5236         } else {
5237                 num_bytes = 0;
5238         }
5239         spin_unlock(&block_rsv->lock);
5240
5241         if (num_bytes > 0) {
5242                 if (dest) {
5243                         spin_lock(&dest->lock);
5244                         if (!dest->full) {
5245                                 u64 bytes_to_add;
5246
5247                                 bytes_to_add = dest->size - dest->reserved;
5248                                 bytes_to_add = min(num_bytes, bytes_to_add);
5249                                 dest->reserved += bytes_to_add;
5250                                 if (dest->reserved >= dest->size)
5251                                         dest->full = 1;
5252                                 num_bytes -= bytes_to_add;
5253                         }
5254                         spin_unlock(&dest->lock);
5255                 }
5256                 if (num_bytes) {
5257                         spin_lock(&space_info->lock);
5258                         space_info->bytes_may_use -= num_bytes;
5259                         trace_btrfs_space_reservation(fs_info, "space_info",
5260                                         space_info->flags, num_bytes, 0);
5261                         spin_unlock(&space_info->lock);
5262                 }
5263         }
5264 }
5265
5266 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
5267                                    struct btrfs_block_rsv *dst, u64 num_bytes)
5268 {
5269         int ret;
5270
5271         ret = block_rsv_use_bytes(src, num_bytes);
5272         if (ret)
5273                 return ret;
5274
5275         block_rsv_add_bytes(dst, num_bytes, 1);
5276         return 0;
5277 }
5278
5279 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5280 {
5281         memset(rsv, 0, sizeof(*rsv));
5282         spin_lock_init(&rsv->lock);
5283         rsv->type = type;
5284 }
5285
5286 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5287                                               unsigned short type)
5288 {
5289         struct btrfs_block_rsv *block_rsv;
5290         struct btrfs_fs_info *fs_info = root->fs_info;
5291
5292         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5293         if (!block_rsv)
5294                 return NULL;
5295
5296         btrfs_init_block_rsv(block_rsv, type);
5297         block_rsv->space_info = __find_space_info(fs_info,
5298                                                   BTRFS_BLOCK_GROUP_METADATA);
5299         return block_rsv;
5300 }
5301
5302 void btrfs_free_block_rsv(struct btrfs_root *root,
5303                           struct btrfs_block_rsv *rsv)
5304 {
5305         if (!rsv)
5306                 return;
5307         btrfs_block_rsv_release(root, rsv, (u64)-1);
5308         kfree(rsv);
5309 }
5310
5311 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5312 {
5313         kfree(rsv);
5314 }
5315
5316 int btrfs_block_rsv_add(struct btrfs_root *root,
5317                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5318                         enum btrfs_reserve_flush_enum flush)
5319 {
5320         int ret;
5321
5322         if (num_bytes == 0)
5323                 return 0;
5324
5325         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5326         if (!ret) {
5327                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5328                 return 0;
5329         }
5330
5331         return ret;
5332 }
5333
5334 int btrfs_block_rsv_check(struct btrfs_root *root,
5335                           struct btrfs_block_rsv *block_rsv, int min_factor)
5336 {
5337         u64 num_bytes = 0;
5338         int ret = -ENOSPC;
5339
5340         if (!block_rsv)
5341                 return 0;
5342
5343         spin_lock(&block_rsv->lock);
5344         num_bytes = div_factor(block_rsv->size, min_factor);
5345         if (block_rsv->reserved >= num_bytes)
5346                 ret = 0;
5347         spin_unlock(&block_rsv->lock);
5348
5349         return ret;
5350 }
5351
5352 int btrfs_block_rsv_refill(struct btrfs_root *root,
5353                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5354                            enum btrfs_reserve_flush_enum flush)
5355 {
5356         u64 num_bytes = 0;
5357         int ret = -ENOSPC;
5358
5359         if (!block_rsv)
5360                 return 0;
5361
5362         spin_lock(&block_rsv->lock);
5363         num_bytes = min_reserved;
5364         if (block_rsv->reserved >= num_bytes)
5365                 ret = 0;
5366         else
5367                 num_bytes -= block_rsv->reserved;
5368         spin_unlock(&block_rsv->lock);
5369
5370         if (!ret)
5371                 return 0;
5372
5373         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5374         if (!ret) {
5375                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5376                 return 0;
5377         }
5378
5379         return ret;
5380 }
5381
5382 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
5383                             struct btrfs_block_rsv *dst_rsv,
5384                             u64 num_bytes)
5385 {
5386         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5387 }
5388
5389 void btrfs_block_rsv_release(struct btrfs_root *root,
5390                              struct btrfs_block_rsv *block_rsv,
5391                              u64 num_bytes)
5392 {
5393         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5394         if (global_rsv == block_rsv ||
5395             block_rsv->space_info != global_rsv->space_info)
5396                 global_rsv = NULL;
5397         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5398                                 num_bytes);
5399 }
5400
5401 /*
5402  * helper to calculate size of global block reservation.
5403  * the desired value is sum of space used by extent tree,
5404  * checksum tree and root tree
5405  */
5406 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
5407 {
5408         struct btrfs_space_info *sinfo;
5409         u64 num_bytes;
5410         u64 meta_used;
5411         u64 data_used;
5412         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
5413
5414         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
5415         spin_lock(&sinfo->lock);
5416         data_used = sinfo->bytes_used;
5417         spin_unlock(&sinfo->lock);
5418
5419         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5420         spin_lock(&sinfo->lock);
5421         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
5422                 data_used = 0;
5423         meta_used = sinfo->bytes_used;
5424         spin_unlock(&sinfo->lock);
5425
5426         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
5427                     csum_size * 2;
5428         num_bytes += div_u64(data_used + meta_used, 50);
5429
5430         if (num_bytes * 3 > meta_used)
5431                 num_bytes = div_u64(meta_used, 3);
5432
5433         return ALIGN(num_bytes, fs_info->extent_root->nodesize << 10);
5434 }
5435
5436 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5437 {
5438         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5439         struct btrfs_space_info *sinfo = block_rsv->space_info;
5440         u64 num_bytes;
5441
5442         num_bytes = calc_global_metadata_size(fs_info);
5443
5444         spin_lock(&sinfo->lock);
5445         spin_lock(&block_rsv->lock);
5446
5447         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5448
5449         if (block_rsv->reserved < block_rsv->size) {
5450                 num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5451                         sinfo->bytes_reserved + sinfo->bytes_readonly +
5452                         sinfo->bytes_may_use;
5453                 if (sinfo->total_bytes > num_bytes) {
5454                         num_bytes = sinfo->total_bytes - num_bytes;
5455                         num_bytes = min(num_bytes,
5456                                         block_rsv->size - block_rsv->reserved);
5457                         block_rsv->reserved += num_bytes;
5458                         sinfo->bytes_may_use += num_bytes;
5459                         trace_btrfs_space_reservation(fs_info, "space_info",
5460                                                       sinfo->flags, num_bytes,
5461                                                       1);
5462                 }
5463         } else if (block_rsv->reserved > block_rsv->size) {
5464                 num_bytes = block_rsv->reserved - block_rsv->size;
5465                 sinfo->bytes_may_use -= num_bytes;
5466                 trace_btrfs_space_reservation(fs_info, "space_info",
5467                                       sinfo->flags, num_bytes, 0);
5468                 block_rsv->reserved = block_rsv->size;
5469         }
5470
5471         if (block_rsv->reserved == block_rsv->size)
5472                 block_rsv->full = 1;
5473         else
5474                 block_rsv->full = 0;
5475
5476         spin_unlock(&block_rsv->lock);
5477         spin_unlock(&sinfo->lock);
5478 }
5479
5480 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5481 {
5482         struct btrfs_space_info *space_info;
5483
5484         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5485         fs_info->chunk_block_rsv.space_info = space_info;
5486
5487         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5488         fs_info->global_block_rsv.space_info = space_info;
5489         fs_info->delalloc_block_rsv.space_info = space_info;
5490         fs_info->trans_block_rsv.space_info = space_info;
5491         fs_info->empty_block_rsv.space_info = space_info;
5492         fs_info->delayed_block_rsv.space_info = space_info;
5493
5494         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5495         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5496         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5497         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5498         if (fs_info->quota_root)
5499                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5500         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5501
5502         update_global_block_rsv(fs_info);
5503 }
5504
5505 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5506 {
5507         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5508                                 (u64)-1);
5509         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5510         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5511         WARN_ON(fs_info->trans_block_rsv.size > 0);
5512         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5513         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5514         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5515         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5516         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5517 }
5518
5519 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5520                                   struct btrfs_root *root)
5521 {
5522         if (!trans->block_rsv)
5523                 return;
5524
5525         if (!trans->bytes_reserved)
5526                 return;
5527
5528         trace_btrfs_space_reservation(root->fs_info, "transaction",
5529                                       trans->transid, trans->bytes_reserved, 0);
5530         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5531         trans->bytes_reserved = 0;
5532 }
5533
5534 /*
5535  * To be called after all the new block groups attached to the transaction
5536  * handle have been created (btrfs_create_pending_block_groups()).
5537  */
5538 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5539 {
5540         struct btrfs_fs_info *fs_info = trans->root->fs_info;
5541
5542         if (!trans->chunk_bytes_reserved)
5543                 return;
5544
5545         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5546
5547         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5548                                 trans->chunk_bytes_reserved);
5549         trans->chunk_bytes_reserved = 0;
5550 }
5551
5552 /* Can only return 0 or -ENOSPC */
5553 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5554                                   struct inode *inode)
5555 {
5556         struct btrfs_root *root = BTRFS_I(inode)->root;
5557         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
5558         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5559
5560         /*
5561          * We need to hold space in order to delete our orphan item once we've
5562          * added it, so this takes the reservation so we can release it later
5563          * when we are truly done with the orphan item.
5564          */
5565         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5566         trace_btrfs_space_reservation(root->fs_info, "orphan",
5567                                       btrfs_ino(inode), num_bytes, 1);
5568         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5569 }
5570
5571 void btrfs_orphan_release_metadata(struct inode *inode)
5572 {
5573         struct btrfs_root *root = BTRFS_I(inode)->root;
5574         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5575         trace_btrfs_space_reservation(root->fs_info, "orphan",
5576                                       btrfs_ino(inode), num_bytes, 0);
5577         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5578 }
5579
5580 /*
5581  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5582  * root: the root of the parent directory
5583  * rsv: block reservation
5584  * items: the number of items that we need do reservation
5585  * qgroup_reserved: used to return the reserved size in qgroup
5586  *
5587  * This function is used to reserve the space for snapshot/subvolume
5588  * creation and deletion. Those operations are different with the
5589  * common file/directory operations, they change two fs/file trees
5590  * and root tree, the number of items that the qgroup reserves is
5591  * different with the free space reservation. So we can not use
5592  * the space reservation mechanism in start_transaction().
5593  */
5594 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5595                                      struct btrfs_block_rsv *rsv,
5596                                      int items,
5597                                      u64 *qgroup_reserved,
5598                                      bool use_global_rsv)
5599 {
5600         u64 num_bytes;
5601         int ret;
5602         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5603
5604         if (root->fs_info->quota_enabled) {
5605                 /* One for parent inode, two for dir entries */
5606                 num_bytes = 3 * root->nodesize;
5607                 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5608                 if (ret)
5609                         return ret;
5610         } else {
5611                 num_bytes = 0;
5612         }
5613
5614         *qgroup_reserved = num_bytes;
5615
5616         num_bytes = btrfs_calc_trans_metadata_size(root, items);
5617         rsv->space_info = __find_space_info(root->fs_info,
5618                                             BTRFS_BLOCK_GROUP_METADATA);
5619         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5620                                   BTRFS_RESERVE_FLUSH_ALL);
5621
5622         if (ret == -ENOSPC && use_global_rsv)
5623                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
5624
5625         if (ret && *qgroup_reserved)
5626                 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5627
5628         return ret;
5629 }
5630
5631 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5632                                       struct btrfs_block_rsv *rsv,
5633                                       u64 qgroup_reserved)
5634 {
5635         btrfs_block_rsv_release(root, rsv, (u64)-1);
5636 }
5637
5638 /**
5639  * drop_outstanding_extent - drop an outstanding extent
5640  * @inode: the inode we're dropping the extent for
5641  * @num_bytes: the number of bytes we're releasing.
5642  *
5643  * This is called when we are freeing up an outstanding extent, either called
5644  * after an error or after an extent is written.  This will return the number of
5645  * reserved extents that need to be freed.  This must be called with
5646  * BTRFS_I(inode)->lock held.
5647  */
5648 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5649 {
5650         unsigned drop_inode_space = 0;
5651         unsigned dropped_extents = 0;
5652         unsigned num_extents = 0;
5653
5654         num_extents = (unsigned)div64_u64(num_bytes +
5655                                           BTRFS_MAX_EXTENT_SIZE - 1,
5656                                           BTRFS_MAX_EXTENT_SIZE);
5657         ASSERT(num_extents);
5658         ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5659         BTRFS_I(inode)->outstanding_extents -= num_extents;
5660
5661         if (BTRFS_I(inode)->outstanding_extents == 0 &&
5662             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5663                                &BTRFS_I(inode)->runtime_flags))
5664                 drop_inode_space = 1;
5665
5666         /*
5667          * If we have more or the same amount of outstanding extents than we have
5668          * reserved then we need to leave the reserved extents count alone.
5669          */
5670         if (BTRFS_I(inode)->outstanding_extents >=
5671             BTRFS_I(inode)->reserved_extents)
5672                 return drop_inode_space;
5673
5674         dropped_extents = BTRFS_I(inode)->reserved_extents -
5675                 BTRFS_I(inode)->outstanding_extents;
5676         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5677         return dropped_extents + drop_inode_space;
5678 }
5679
5680 /**
5681  * calc_csum_metadata_size - return the amount of metadata space that must be
5682  *      reserved/freed for the given bytes.
5683  * @inode: the inode we're manipulating
5684  * @num_bytes: the number of bytes in question
5685  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5686  *
5687  * This adjusts the number of csum_bytes in the inode and then returns the
5688  * correct amount of metadata that must either be reserved or freed.  We
5689  * calculate how many checksums we can fit into one leaf and then divide the
5690  * number of bytes that will need to be checksumed by this value to figure out
5691  * how many checksums will be required.  If we are adding bytes then the number
5692  * may go up and we will return the number of additional bytes that must be
5693  * reserved.  If it is going down we will return the number of bytes that must
5694  * be freed.
5695  *
5696  * This must be called with BTRFS_I(inode)->lock held.
5697  */
5698 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5699                                    int reserve)
5700 {
5701         struct btrfs_root *root = BTRFS_I(inode)->root;
5702         u64 old_csums, num_csums;
5703
5704         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5705             BTRFS_I(inode)->csum_bytes == 0)
5706                 return 0;
5707
5708         old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5709         if (reserve)
5710                 BTRFS_I(inode)->csum_bytes += num_bytes;
5711         else
5712                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5713         num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5714
5715         /* No change, no need to reserve more */
5716         if (old_csums == num_csums)
5717                 return 0;
5718
5719         if (reserve)
5720                 return btrfs_calc_trans_metadata_size(root,
5721                                                       num_csums - old_csums);
5722
5723         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5724 }
5725
5726 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5727 {
5728         struct btrfs_root *root = BTRFS_I(inode)->root;
5729         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5730         u64 to_reserve = 0;
5731         u64 csum_bytes;
5732         unsigned nr_extents = 0;
5733         int extra_reserve = 0;
5734         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5735         int ret = 0;
5736         bool delalloc_lock = true;
5737         u64 to_free = 0;
5738         unsigned dropped;
5739
5740         /* If we are a free space inode we need to not flush since we will be in
5741          * the middle of a transaction commit.  We also don't need the delalloc
5742          * mutex since we won't race with anybody.  We need this mostly to make
5743          * lockdep shut its filthy mouth.
5744          */
5745         if (btrfs_is_free_space_inode(inode)) {
5746                 flush = BTRFS_RESERVE_NO_FLUSH;
5747                 delalloc_lock = false;
5748         }
5749
5750         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5751             btrfs_transaction_in_commit(root->fs_info))
5752                 schedule_timeout(1);
5753
5754         if (delalloc_lock)
5755                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5756
5757         num_bytes = ALIGN(num_bytes, root->sectorsize);
5758
5759         spin_lock(&BTRFS_I(inode)->lock);
5760         nr_extents = (unsigned)div64_u64(num_bytes +
5761                                          BTRFS_MAX_EXTENT_SIZE - 1,
5762                                          BTRFS_MAX_EXTENT_SIZE);
5763         BTRFS_I(inode)->outstanding_extents += nr_extents;
5764         nr_extents = 0;
5765
5766         if (BTRFS_I(inode)->outstanding_extents >
5767             BTRFS_I(inode)->reserved_extents)
5768                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5769                         BTRFS_I(inode)->reserved_extents;
5770
5771         /*
5772          * Add an item to reserve for updating the inode when we complete the
5773          * delalloc io.
5774          */
5775         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5776                       &BTRFS_I(inode)->runtime_flags)) {
5777                 nr_extents++;
5778                 extra_reserve = 1;
5779         }
5780
5781         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5782         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5783         csum_bytes = BTRFS_I(inode)->csum_bytes;
5784         spin_unlock(&BTRFS_I(inode)->lock);
5785
5786         if (root->fs_info->quota_enabled) {
5787                 ret = btrfs_qgroup_reserve_meta(root,
5788                                 nr_extents * root->nodesize);
5789                 if (ret)
5790                         goto out_fail;
5791         }
5792
5793         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5794         if (unlikely(ret)) {
5795                 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5796                 goto out_fail;
5797         }
5798
5799         spin_lock(&BTRFS_I(inode)->lock);
5800         if (extra_reserve) {
5801                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5802                         &BTRFS_I(inode)->runtime_flags);
5803                 nr_extents--;
5804         }
5805         BTRFS_I(inode)->reserved_extents += nr_extents;
5806         spin_unlock(&BTRFS_I(inode)->lock);
5807
5808         if (delalloc_lock)
5809                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5810
5811         if (to_reserve)
5812                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5813                                               btrfs_ino(inode), to_reserve, 1);
5814         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5815
5816         return 0;
5817
5818 out_fail:
5819         spin_lock(&BTRFS_I(inode)->lock);
5820         dropped = drop_outstanding_extent(inode, num_bytes);
5821         /*
5822          * If the inodes csum_bytes is the same as the original
5823          * csum_bytes then we know we haven't raced with any free()ers
5824          * so we can just reduce our inodes csum bytes and carry on.
5825          */
5826         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5827                 calc_csum_metadata_size(inode, num_bytes, 0);
5828         } else {
5829                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5830                 u64 bytes;
5831
5832                 /*
5833                  * This is tricky, but first we need to figure out how much we
5834                  * freed from any free-ers that occurred during this
5835                  * reservation, so we reset ->csum_bytes to the csum_bytes
5836                  * before we dropped our lock, and then call the free for the
5837                  * number of bytes that were freed while we were trying our
5838                  * reservation.
5839                  */
5840                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5841                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5842                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5843
5844
5845                 /*
5846                  * Now we need to see how much we would have freed had we not
5847                  * been making this reservation and our ->csum_bytes were not
5848                  * artificially inflated.
5849                  */
5850                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5851                 bytes = csum_bytes - orig_csum_bytes;
5852                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5853
5854                 /*
5855                  * Now reset ->csum_bytes to what it should be.  If bytes is
5856                  * more than to_free then we would have freed more space had we
5857                  * not had an artificially high ->csum_bytes, so we need to free
5858                  * the remainder.  If bytes is the same or less then we don't
5859                  * need to do anything, the other free-ers did the correct
5860                  * thing.
5861                  */
5862                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5863                 if (bytes > to_free)
5864                         to_free = bytes - to_free;
5865                 else
5866                         to_free = 0;
5867         }
5868         spin_unlock(&BTRFS_I(inode)->lock);
5869         if (dropped)
5870                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5871
5872         if (to_free) {
5873                 btrfs_block_rsv_release(root, block_rsv, to_free);
5874                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5875                                               btrfs_ino(inode), to_free, 0);
5876         }
5877         if (delalloc_lock)
5878                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5879         return ret;
5880 }
5881
5882 /**
5883  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5884  * @inode: the inode to release the reservation for
5885  * @num_bytes: the number of bytes we're releasing
5886  *
5887  * This will release the metadata reservation for an inode.  This can be called
5888  * once we complete IO for a given set of bytes to release their metadata
5889  * reservations.
5890  */
5891 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5892 {
5893         struct btrfs_root *root = BTRFS_I(inode)->root;
5894         u64 to_free = 0;
5895         unsigned dropped;
5896
5897         num_bytes = ALIGN(num_bytes, root->sectorsize);
5898         spin_lock(&BTRFS_I(inode)->lock);
5899         dropped = drop_outstanding_extent(inode, num_bytes);
5900
5901         if (num_bytes)
5902                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5903         spin_unlock(&BTRFS_I(inode)->lock);
5904         if (dropped > 0)
5905                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5906
5907         if (btrfs_test_is_dummy_root(root))
5908                 return;
5909
5910         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5911                                       btrfs_ino(inode), to_free, 0);
5912
5913         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5914                                 to_free);
5915 }
5916
5917 /**
5918  * btrfs_delalloc_reserve_space - reserve data and metadata space for
5919  * delalloc
5920  * @inode: inode we're writing to
5921  * @start: start range we are writing to
5922  * @len: how long the range we are writing to
5923  *
5924  * TODO: This function will finally replace old btrfs_delalloc_reserve_space()
5925  *
5926  * This will do the following things
5927  *
5928  * o reserve space in data space info for num bytes
5929  *   and reserve precious corresponding qgroup space
5930  *   (Done in check_data_free_space)
5931  *
5932  * o reserve space for metadata space, based on the number of outstanding
5933  *   extents and how much csums will be needed
5934  *   also reserve metadata space in a per root over-reserve method.
5935  * o add to the inodes->delalloc_bytes
5936  * o add it to the fs_info's delalloc inodes list.
5937  *   (Above 3 all done in delalloc_reserve_metadata)
5938  *
5939  * Return 0 for success
5940  * Return <0 for error(-ENOSPC or -EQUOT)
5941  */
5942 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
5943 {
5944         int ret;
5945
5946         ret = btrfs_check_data_free_space(inode, start, len);
5947         if (ret < 0)
5948                 return ret;
5949         ret = btrfs_delalloc_reserve_metadata(inode, len);
5950         if (ret < 0)
5951                 btrfs_free_reserved_data_space(inode, start, len);
5952         return ret;
5953 }
5954
5955 /**
5956  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5957  * @inode: inode we're releasing space for
5958  * @start: start position of the space already reserved
5959  * @len: the len of the space already reserved
5960  *
5961  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5962  * called in the case that we don't need the metadata AND data reservations
5963  * anymore.  So if there is an error or we insert an inline extent.
5964  *
5965  * This function will release the metadata space that was not used and will
5966  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5967  * list if there are no delalloc bytes left.
5968  * Also it will handle the qgroup reserved space.
5969  */
5970 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
5971 {
5972         btrfs_delalloc_release_metadata(inode, len);
5973         btrfs_free_reserved_data_space(inode, start, len);
5974 }
5975
5976 static int update_block_group(struct btrfs_trans_handle *trans,
5977                               struct btrfs_root *root, u64 bytenr,
5978                               u64 num_bytes, int alloc)
5979 {
5980         struct btrfs_block_group_cache *cache = NULL;
5981         struct btrfs_fs_info *info = root->fs_info;
5982         u64 total = num_bytes;
5983         u64 old_val;
5984         u64 byte_in_group;
5985         int factor;
5986
5987         /* block accounting for super block */
5988         spin_lock(&info->delalloc_root_lock);
5989         old_val = btrfs_super_bytes_used(info->super_copy);
5990         if (alloc)
5991                 old_val += num_bytes;
5992         else
5993                 old_val -= num_bytes;
5994         btrfs_set_super_bytes_used(info->super_copy, old_val);
5995         spin_unlock(&info->delalloc_root_lock);
5996
5997         while (total) {
5998                 cache = btrfs_lookup_block_group(info, bytenr);
5999                 if (!cache)
6000                         return -ENOENT;
6001                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6002                                     BTRFS_BLOCK_GROUP_RAID1 |
6003                                     BTRFS_BLOCK_GROUP_RAID10))
6004                         factor = 2;
6005                 else
6006                         factor = 1;
6007                 /*
6008                  * If this block group has free space cache written out, we
6009                  * need to make sure to load it if we are removing space.  This
6010                  * is because we need the unpinning stage to actually add the
6011                  * space back to the block group, otherwise we will leak space.
6012                  */
6013                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6014                         cache_block_group(cache, 1);
6015
6016                 byte_in_group = bytenr - cache->key.objectid;
6017                 WARN_ON(byte_in_group > cache->key.offset);
6018
6019                 spin_lock(&cache->space_info->lock);
6020                 spin_lock(&cache->lock);
6021
6022                 if (btrfs_test_opt(root, SPACE_CACHE) &&
6023                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6024                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6025
6026                 old_val = btrfs_block_group_used(&cache->item);
6027                 num_bytes = min(total, cache->key.offset - byte_in_group);
6028                 if (alloc) {
6029                         old_val += num_bytes;
6030                         btrfs_set_block_group_used(&cache->item, old_val);
6031                         cache->reserved -= num_bytes;
6032                         cache->space_info->bytes_reserved -= num_bytes;
6033                         cache->space_info->bytes_used += num_bytes;
6034                         cache->space_info->disk_used += num_bytes * factor;
6035                         spin_unlock(&cache->lock);
6036                         spin_unlock(&cache->space_info->lock);
6037                 } else {
6038                         old_val -= num_bytes;
6039                         btrfs_set_block_group_used(&cache->item, old_val);
6040                         cache->pinned += num_bytes;
6041                         cache->space_info->bytes_pinned += num_bytes;
6042                         cache->space_info->bytes_used -= num_bytes;
6043                         cache->space_info->disk_used -= num_bytes * factor;
6044                         spin_unlock(&cache->lock);
6045                         spin_unlock(&cache->space_info->lock);
6046
6047                         set_extent_dirty(info->pinned_extents,
6048                                          bytenr, bytenr + num_bytes - 1,
6049                                          GFP_NOFS | __GFP_NOFAIL);
6050                 }
6051
6052                 spin_lock(&trans->transaction->dirty_bgs_lock);
6053                 if (list_empty(&cache->dirty_list)) {
6054                         list_add_tail(&cache->dirty_list,
6055                                       &trans->transaction->dirty_bgs);
6056                                 trans->transaction->num_dirty_bgs++;
6057                         btrfs_get_block_group(cache);
6058                 }
6059                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6060
6061                 /*
6062                  * No longer have used bytes in this block group, queue it for
6063                  * deletion. We do this after adding the block group to the
6064                  * dirty list to avoid races between cleaner kthread and space
6065                  * cache writeout.
6066                  */
6067                 if (!alloc && old_val == 0) {
6068                         spin_lock(&info->unused_bgs_lock);
6069                         if (list_empty(&cache->bg_list)) {
6070                                 btrfs_get_block_group(cache);
6071                                 list_add_tail(&cache->bg_list,
6072                                               &info->unused_bgs);
6073                         }
6074                         spin_unlock(&info->unused_bgs_lock);
6075                 }
6076
6077                 btrfs_put_block_group(cache);
6078                 total -= num_bytes;
6079                 bytenr += num_bytes;
6080         }
6081         return 0;
6082 }
6083
6084 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
6085 {
6086         struct btrfs_block_group_cache *cache;
6087         u64 bytenr;
6088
6089         spin_lock(&root->fs_info->block_group_cache_lock);
6090         bytenr = root->fs_info->first_logical_byte;
6091         spin_unlock(&root->fs_info->block_group_cache_lock);
6092
6093         if (bytenr < (u64)-1)
6094                 return bytenr;
6095
6096         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
6097         if (!cache)
6098                 return 0;
6099
6100         bytenr = cache->key.objectid;
6101         btrfs_put_block_group(cache);
6102
6103         return bytenr;
6104 }
6105
6106 static int pin_down_extent(struct btrfs_root *root,
6107                            struct btrfs_block_group_cache *cache,
6108                            u64 bytenr, u64 num_bytes, int reserved)
6109 {
6110         spin_lock(&cache->space_info->lock);
6111         spin_lock(&cache->lock);
6112         cache->pinned += num_bytes;
6113         cache->space_info->bytes_pinned += num_bytes;
6114         if (reserved) {
6115                 cache->reserved -= num_bytes;
6116                 cache->space_info->bytes_reserved -= num_bytes;
6117         }
6118         spin_unlock(&cache->lock);
6119         spin_unlock(&cache->space_info->lock);
6120
6121         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
6122                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6123         if (reserved)
6124                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
6125         return 0;
6126 }
6127
6128 /*
6129  * this function must be called within transaction
6130  */
6131 int btrfs_pin_extent(struct btrfs_root *root,
6132                      u64 bytenr, u64 num_bytes, int reserved)
6133 {
6134         struct btrfs_block_group_cache *cache;
6135
6136         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6137         BUG_ON(!cache); /* Logic error */
6138
6139         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
6140
6141         btrfs_put_block_group(cache);
6142         return 0;
6143 }
6144
6145 /*
6146  * this function must be called within transaction
6147  */
6148 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
6149                                     u64 bytenr, u64 num_bytes)
6150 {
6151         struct btrfs_block_group_cache *cache;
6152         int ret;
6153
6154         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
6155         if (!cache)
6156                 return -EINVAL;
6157
6158         /*
6159          * pull in the free space cache (if any) so that our pin
6160          * removes the free space from the cache.  We have load_only set
6161          * to one because the slow code to read in the free extents does check
6162          * the pinned extents.
6163          */
6164         cache_block_group(cache, 1);
6165
6166         pin_down_extent(root, cache, bytenr, num_bytes, 0);
6167
6168         /* remove us from the free space cache (if we're there at all) */
6169         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6170         btrfs_put_block_group(cache);
6171         return ret;
6172 }
6173
6174 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
6175 {
6176         int ret;
6177         struct btrfs_block_group_cache *block_group;
6178         struct btrfs_caching_control *caching_ctl;
6179
6180         block_group = btrfs_lookup_block_group(root->fs_info, start);
6181         if (!block_group)
6182                 return -EINVAL;
6183
6184         cache_block_group(block_group, 0);
6185         caching_ctl = get_caching_control(block_group);
6186
6187         if (!caching_ctl) {
6188                 /* Logic error */
6189                 BUG_ON(!block_group_cache_done(block_group));
6190                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6191         } else {
6192                 mutex_lock(&caching_ctl->mutex);
6193
6194                 if (start >= caching_ctl->progress) {
6195                         ret = add_excluded_extent(root, start, num_bytes);
6196                 } else if (start + num_bytes <= caching_ctl->progress) {
6197                         ret = btrfs_remove_free_space(block_group,
6198                                                       start, num_bytes);
6199                 } else {
6200                         num_bytes = caching_ctl->progress - start;
6201                         ret = btrfs_remove_free_space(block_group,
6202                                                       start, num_bytes);
6203                         if (ret)
6204                                 goto out_lock;
6205
6206                         num_bytes = (start + num_bytes) -
6207                                 caching_ctl->progress;
6208                         start = caching_ctl->progress;
6209                         ret = add_excluded_extent(root, start, num_bytes);
6210                 }
6211 out_lock:
6212                 mutex_unlock(&caching_ctl->mutex);
6213                 put_caching_control(caching_ctl);
6214         }
6215         btrfs_put_block_group(block_group);
6216         return ret;
6217 }
6218
6219 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6220                                  struct extent_buffer *eb)
6221 {
6222         struct btrfs_file_extent_item *item;
6223         struct btrfs_key key;
6224         int found_type;
6225         int i;
6226
6227         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6228                 return 0;
6229
6230         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6231                 btrfs_item_key_to_cpu(eb, &key, i);
6232                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6233                         continue;
6234                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6235                 found_type = btrfs_file_extent_type(eb, item);
6236                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6237                         continue;
6238                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6239                         continue;
6240                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6241                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6242                 __exclude_logged_extent(log, key.objectid, key.offset);
6243         }
6244
6245         return 0;
6246 }
6247
6248 static void
6249 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6250 {
6251         atomic_inc(&bg->reservations);
6252 }
6253
6254 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6255                                         const u64 start)
6256 {
6257         struct btrfs_block_group_cache *bg;
6258
6259         bg = btrfs_lookup_block_group(fs_info, start);
6260         ASSERT(bg);
6261         if (atomic_dec_and_test(&bg->reservations))
6262                 wake_up_atomic_t(&bg->reservations);
6263         btrfs_put_block_group(bg);
6264 }
6265
6266 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6267 {
6268         schedule();
6269         return 0;
6270 }
6271
6272 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6273 {
6274         struct btrfs_space_info *space_info = bg->space_info;
6275
6276         ASSERT(bg->ro);
6277
6278         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6279                 return;
6280
6281         /*
6282          * Our block group is read only but before we set it to read only,
6283          * some task might have had allocated an extent from it already, but it
6284          * has not yet created a respective ordered extent (and added it to a
6285          * root's list of ordered extents).
6286          * Therefore wait for any task currently allocating extents, since the
6287          * block group's reservations counter is incremented while a read lock
6288          * on the groups' semaphore is held and decremented after releasing
6289          * the read access on that semaphore and creating the ordered extent.
6290          */
6291         down_write(&space_info->groups_sem);
6292         up_write(&space_info->groups_sem);
6293
6294         wait_on_atomic_t(&bg->reservations,
6295                          btrfs_wait_bg_reservations_atomic_t,
6296                          TASK_UNINTERRUPTIBLE);
6297 }
6298
6299 /**
6300  * btrfs_update_reserved_bytes - update the block_group and space info counters
6301  * @cache:      The cache we are manipulating
6302  * @num_bytes:  The number of bytes in question
6303  * @reserve:    One of the reservation enums
6304  * @delalloc:   The blocks are allocated for the delalloc write
6305  *
6306  * This is called by the allocator when it reserves space, or by somebody who is
6307  * freeing space that was never actually used on disk.  For example if you
6308  * reserve some space for a new leaf in transaction A and before transaction A
6309  * commits you free that leaf, you call this with reserve set to 0 in order to
6310  * clear the reservation.
6311  *
6312  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
6313  * ENOSPC accounting.  For data we handle the reservation through clearing the
6314  * delalloc bits in the io_tree.  We have to do this since we could end up
6315  * allocating less disk space for the amount of data we have reserved in the
6316  * case of compression.
6317  *
6318  * If this is a reservation and the block group has become read only we cannot
6319  * make the reservation and return -EAGAIN, otherwise this function always
6320  * succeeds.
6321  */
6322 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
6323                                        u64 num_bytes, int reserve, int delalloc)
6324 {
6325         struct btrfs_space_info *space_info = cache->space_info;
6326         int ret = 0;
6327
6328         spin_lock(&space_info->lock);
6329         spin_lock(&cache->lock);
6330         if (reserve != RESERVE_FREE) {
6331                 if (cache->ro) {
6332                         ret = -EAGAIN;
6333                 } else {
6334                         cache->reserved += num_bytes;
6335                         space_info->bytes_reserved += num_bytes;
6336                         if (reserve == RESERVE_ALLOC) {
6337                                 trace_btrfs_space_reservation(cache->fs_info,
6338                                                 "space_info", space_info->flags,
6339                                                 num_bytes, 0);
6340                                 space_info->bytes_may_use -= num_bytes;
6341                         }
6342
6343                         if (delalloc)
6344                                 cache->delalloc_bytes += num_bytes;
6345                 }
6346         } else {
6347                 if (cache->ro)
6348                         space_info->bytes_readonly += num_bytes;
6349                 cache->reserved -= num_bytes;
6350                 space_info->bytes_reserved -= num_bytes;
6351
6352                 if (delalloc)
6353                         cache->delalloc_bytes -= num_bytes;
6354         }
6355         spin_unlock(&cache->lock);
6356         spin_unlock(&space_info->lock);
6357         return ret;
6358 }
6359
6360 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6361                                 struct btrfs_root *root)
6362 {
6363         struct btrfs_fs_info *fs_info = root->fs_info;
6364         struct btrfs_caching_control *next;
6365         struct btrfs_caching_control *caching_ctl;
6366         struct btrfs_block_group_cache *cache;
6367
6368         down_write(&fs_info->commit_root_sem);
6369
6370         list_for_each_entry_safe(caching_ctl, next,
6371                                  &fs_info->caching_block_groups, list) {
6372                 cache = caching_ctl->block_group;
6373                 if (block_group_cache_done(cache)) {
6374                         cache->last_byte_to_unpin = (u64)-1;
6375                         list_del_init(&caching_ctl->list);
6376                         put_caching_control(caching_ctl);
6377                 } else {
6378                         cache->last_byte_to_unpin = caching_ctl->progress;
6379                 }
6380         }
6381
6382         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6383                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6384         else
6385                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6386
6387         up_write(&fs_info->commit_root_sem);
6388
6389         update_global_block_rsv(fs_info);
6390 }
6391
6392 /*
6393  * Returns the free cluster for the given space info and sets empty_cluster to
6394  * what it should be based on the mount options.
6395  */
6396 static struct btrfs_free_cluster *
6397 fetch_cluster_info(struct btrfs_root *root, struct btrfs_space_info *space_info,
6398                    u64 *empty_cluster)
6399 {
6400         struct btrfs_free_cluster *ret = NULL;
6401         bool ssd = btrfs_test_opt(root, SSD);
6402
6403         *empty_cluster = 0;
6404         if (btrfs_mixed_space_info(space_info))
6405                 return ret;
6406
6407         if (ssd)
6408                 *empty_cluster = SZ_2M;
6409         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6410                 ret = &root->fs_info->meta_alloc_cluster;
6411                 if (!ssd)
6412                         *empty_cluster = SZ_64K;
6413         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6414                 ret = &root->fs_info->data_alloc_cluster;
6415         }
6416
6417         return ret;
6418 }
6419
6420 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6421                               const bool return_free_space)
6422 {
6423         struct btrfs_fs_info *fs_info = root->fs_info;
6424         struct btrfs_block_group_cache *cache = NULL;
6425         struct btrfs_space_info *space_info;
6426         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6427         struct btrfs_free_cluster *cluster = NULL;
6428         u64 len;
6429         u64 total_unpinned = 0;
6430         u64 empty_cluster = 0;
6431         bool readonly;
6432
6433         while (start <= end) {
6434                 readonly = false;
6435                 if (!cache ||
6436                     start >= cache->key.objectid + cache->key.offset) {
6437                         if (cache)
6438                                 btrfs_put_block_group(cache);
6439                         total_unpinned = 0;
6440                         cache = btrfs_lookup_block_group(fs_info, start);
6441                         BUG_ON(!cache); /* Logic error */
6442
6443                         cluster = fetch_cluster_info(root,
6444                                                      cache->space_info,
6445                                                      &empty_cluster);
6446                         empty_cluster <<= 1;
6447                 }
6448
6449                 len = cache->key.objectid + cache->key.offset - start;
6450                 len = min(len, end + 1 - start);
6451
6452                 if (start < cache->last_byte_to_unpin) {
6453                         len = min(len, cache->last_byte_to_unpin - start);
6454                         if (return_free_space)
6455                                 btrfs_add_free_space(cache, start, len);
6456                 }
6457
6458                 start += len;
6459                 total_unpinned += len;
6460                 space_info = cache->space_info;
6461
6462                 /*
6463                  * If this space cluster has been marked as fragmented and we've
6464                  * unpinned enough in this block group to potentially allow a
6465                  * cluster to be created inside of it go ahead and clear the
6466                  * fragmented check.
6467                  */
6468                 if (cluster && cluster->fragmented &&
6469                     total_unpinned > empty_cluster) {
6470                         spin_lock(&cluster->lock);
6471                         cluster->fragmented = 0;
6472                         spin_unlock(&cluster->lock);
6473                 }
6474
6475                 spin_lock(&space_info->lock);
6476                 spin_lock(&cache->lock);
6477                 cache->pinned -= len;
6478                 space_info->bytes_pinned -= len;
6479                 space_info->max_extent_size = 0;
6480                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6481                 if (cache->ro) {
6482                         space_info->bytes_readonly += len;
6483                         readonly = true;
6484                 }
6485                 spin_unlock(&cache->lock);
6486                 if (!readonly && global_rsv->space_info == space_info) {
6487                         spin_lock(&global_rsv->lock);
6488                         if (!global_rsv->full) {
6489                                 len = min(len, global_rsv->size -
6490                                           global_rsv->reserved);
6491                                 global_rsv->reserved += len;
6492                                 space_info->bytes_may_use += len;
6493                                 if (global_rsv->reserved >= global_rsv->size)
6494                                         global_rsv->full = 1;
6495                         }
6496                         spin_unlock(&global_rsv->lock);
6497                 }
6498                 spin_unlock(&space_info->lock);
6499         }
6500
6501         if (cache)
6502                 btrfs_put_block_group(cache);
6503         return 0;
6504 }
6505
6506 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6507                                struct btrfs_root *root)
6508 {
6509         struct btrfs_fs_info *fs_info = root->fs_info;
6510         struct btrfs_block_group_cache *block_group, *tmp;
6511         struct list_head *deleted_bgs;
6512         struct extent_io_tree *unpin;
6513         u64 start;
6514         u64 end;
6515         int ret;
6516
6517         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6518                 unpin = &fs_info->freed_extents[1];
6519         else
6520                 unpin = &fs_info->freed_extents[0];
6521
6522         while (!trans->aborted) {
6523                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6524                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6525                                             EXTENT_DIRTY, NULL);
6526                 if (ret) {
6527                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6528                         break;
6529                 }
6530
6531                 if (btrfs_test_opt(root, DISCARD))
6532                         ret = btrfs_discard_extent(root, start,
6533                                                    end + 1 - start, NULL);
6534
6535                 clear_extent_dirty(unpin, start, end);
6536                 unpin_extent_range(root, start, end, true);
6537                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6538                 cond_resched();
6539         }
6540
6541         /*
6542          * Transaction is finished.  We don't need the lock anymore.  We
6543          * do need to clean up the block groups in case of a transaction
6544          * abort.
6545          */
6546         deleted_bgs = &trans->transaction->deleted_bgs;
6547         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6548                 u64 trimmed = 0;
6549
6550                 ret = -EROFS;
6551                 if (!trans->aborted)
6552                         ret = btrfs_discard_extent(root,
6553                                                    block_group->key.objectid,
6554                                                    block_group->key.offset,
6555                                                    &trimmed);
6556
6557                 list_del_init(&block_group->bg_list);
6558                 btrfs_put_block_group_trimming(block_group);
6559                 btrfs_put_block_group(block_group);
6560
6561                 if (ret) {
6562                         const char *errstr = btrfs_decode_error(ret);
6563                         btrfs_warn(fs_info,
6564                                    "Discard failed while removing blockgroup: errno=%d %s\n",
6565                                    ret, errstr);
6566                 }
6567         }
6568
6569         return 0;
6570 }
6571
6572 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6573                              u64 owner, u64 root_objectid)
6574 {
6575         struct btrfs_space_info *space_info;
6576         u64 flags;
6577
6578         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6579                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6580                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
6581                 else
6582                         flags = BTRFS_BLOCK_GROUP_METADATA;
6583         } else {
6584                 flags = BTRFS_BLOCK_GROUP_DATA;
6585         }
6586
6587         space_info = __find_space_info(fs_info, flags);
6588         BUG_ON(!space_info); /* Logic bug */
6589         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6590 }
6591
6592
6593 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6594                                 struct btrfs_root *root,
6595                                 struct btrfs_delayed_ref_node *node, u64 parent,
6596                                 u64 root_objectid, u64 owner_objectid,
6597                                 u64 owner_offset, int refs_to_drop,
6598                                 struct btrfs_delayed_extent_op *extent_op)
6599 {
6600         struct btrfs_key key;
6601         struct btrfs_path *path;
6602         struct btrfs_fs_info *info = root->fs_info;
6603         struct btrfs_root *extent_root = info->extent_root;
6604         struct extent_buffer *leaf;
6605         struct btrfs_extent_item *ei;
6606         struct btrfs_extent_inline_ref *iref;
6607         int ret;
6608         int is_data;
6609         int extent_slot = 0;
6610         int found_extent = 0;
6611         int num_to_del = 1;
6612         u32 item_size;
6613         u64 refs;
6614         u64 bytenr = node->bytenr;
6615         u64 num_bytes = node->num_bytes;
6616         int last_ref = 0;
6617         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6618                                                  SKINNY_METADATA);
6619
6620         path = btrfs_alloc_path();
6621         if (!path)
6622                 return -ENOMEM;
6623
6624         path->reada = READA_FORWARD;
6625         path->leave_spinning = 1;
6626
6627         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6628         BUG_ON(!is_data && refs_to_drop != 1);
6629
6630         if (is_data)
6631                 skinny_metadata = 0;
6632
6633         ret = lookup_extent_backref(trans, extent_root, path, &iref,
6634                                     bytenr, num_bytes, parent,
6635                                     root_objectid, owner_objectid,
6636                                     owner_offset);
6637         if (ret == 0) {
6638                 extent_slot = path->slots[0];
6639                 while (extent_slot >= 0) {
6640                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6641                                               extent_slot);
6642                         if (key.objectid != bytenr)
6643                                 break;
6644                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6645                             key.offset == num_bytes) {
6646                                 found_extent = 1;
6647                                 break;
6648                         }
6649                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6650                             key.offset == owner_objectid) {
6651                                 found_extent = 1;
6652                                 break;
6653                         }
6654                         if (path->slots[0] - extent_slot > 5)
6655                                 break;
6656                         extent_slot--;
6657                 }
6658 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6659                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6660                 if (found_extent && item_size < sizeof(*ei))
6661                         found_extent = 0;
6662 #endif
6663                 if (!found_extent) {
6664                         BUG_ON(iref);
6665                         ret = remove_extent_backref(trans, extent_root, path,
6666                                                     NULL, refs_to_drop,
6667                                                     is_data, &last_ref);
6668                         if (ret) {
6669                                 btrfs_abort_transaction(trans, extent_root, ret);
6670                                 goto out;
6671                         }
6672                         btrfs_release_path(path);
6673                         path->leave_spinning = 1;
6674
6675                         key.objectid = bytenr;
6676                         key.type = BTRFS_EXTENT_ITEM_KEY;
6677                         key.offset = num_bytes;
6678
6679                         if (!is_data && skinny_metadata) {
6680                                 key.type = BTRFS_METADATA_ITEM_KEY;
6681                                 key.offset = owner_objectid;
6682                         }
6683
6684                         ret = btrfs_search_slot(trans, extent_root,
6685                                                 &key, path, -1, 1);
6686                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6687                                 /*
6688                                  * Couldn't find our skinny metadata item,
6689                                  * see if we have ye olde extent item.
6690                                  */
6691                                 path->slots[0]--;
6692                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6693                                                       path->slots[0]);
6694                                 if (key.objectid == bytenr &&
6695                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6696                                     key.offset == num_bytes)
6697                                         ret = 0;
6698                         }
6699
6700                         if (ret > 0 && skinny_metadata) {
6701                                 skinny_metadata = false;
6702                                 key.objectid = bytenr;
6703                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6704                                 key.offset = num_bytes;
6705                                 btrfs_release_path(path);
6706                                 ret = btrfs_search_slot(trans, extent_root,
6707                                                         &key, path, -1, 1);
6708                         }
6709
6710                         if (ret) {
6711                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6712                                         ret, bytenr);
6713                                 if (ret > 0)
6714                                         btrfs_print_leaf(extent_root,
6715                                                          path->nodes[0]);
6716                         }
6717                         if (ret < 0) {
6718                                 btrfs_abort_transaction(trans, extent_root, ret);
6719                                 goto out;
6720                         }
6721                         extent_slot = path->slots[0];
6722                 }
6723         } else if (WARN_ON(ret == -ENOENT)) {
6724                 btrfs_print_leaf(extent_root, path->nodes[0]);
6725                 btrfs_err(info,
6726                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6727                         bytenr, parent, root_objectid, owner_objectid,
6728                         owner_offset);
6729                 btrfs_abort_transaction(trans, extent_root, ret);
6730                 goto out;
6731         } else {
6732                 btrfs_abort_transaction(trans, extent_root, ret);
6733                 goto out;
6734         }
6735
6736         leaf = path->nodes[0];
6737         item_size = btrfs_item_size_nr(leaf, extent_slot);
6738 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6739         if (item_size < sizeof(*ei)) {
6740                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6741                 ret = convert_extent_item_v0(trans, extent_root, path,
6742                                              owner_objectid, 0);
6743                 if (ret < 0) {
6744                         btrfs_abort_transaction(trans, extent_root, ret);
6745                         goto out;
6746                 }
6747
6748                 btrfs_release_path(path);
6749                 path->leave_spinning = 1;
6750
6751                 key.objectid = bytenr;
6752                 key.type = BTRFS_EXTENT_ITEM_KEY;
6753                 key.offset = num_bytes;
6754
6755                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6756                                         -1, 1);
6757                 if (ret) {
6758                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6759                                 ret, bytenr);
6760                         btrfs_print_leaf(extent_root, path->nodes[0]);
6761                 }
6762                 if (ret < 0) {
6763                         btrfs_abort_transaction(trans, extent_root, ret);
6764                         goto out;
6765                 }
6766
6767                 extent_slot = path->slots[0];
6768                 leaf = path->nodes[0];
6769                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6770         }
6771 #endif
6772         BUG_ON(item_size < sizeof(*ei));
6773         ei = btrfs_item_ptr(leaf, extent_slot,
6774                             struct btrfs_extent_item);
6775         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6776             key.type == BTRFS_EXTENT_ITEM_KEY) {
6777                 struct btrfs_tree_block_info *bi;
6778                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6779                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6780                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6781         }
6782
6783         refs = btrfs_extent_refs(leaf, ei);
6784         if (refs < refs_to_drop) {
6785                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
6786                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
6787                 ret = -EINVAL;
6788                 btrfs_abort_transaction(trans, extent_root, ret);
6789                 goto out;
6790         }
6791         refs -= refs_to_drop;
6792
6793         if (refs > 0) {
6794                 if (extent_op)
6795                         __run_delayed_extent_op(extent_op, leaf, ei);
6796                 /*
6797                  * In the case of inline back ref, reference count will
6798                  * be updated by remove_extent_backref
6799                  */
6800                 if (iref) {
6801                         BUG_ON(!found_extent);
6802                 } else {
6803                         btrfs_set_extent_refs(leaf, ei, refs);
6804                         btrfs_mark_buffer_dirty(leaf);
6805                 }
6806                 if (found_extent) {
6807                         ret = remove_extent_backref(trans, extent_root, path,
6808                                                     iref, refs_to_drop,
6809                                                     is_data, &last_ref);
6810                         if (ret) {
6811                                 btrfs_abort_transaction(trans, extent_root, ret);
6812                                 goto out;
6813                         }
6814                 }
6815                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
6816                                  root_objectid);
6817         } else {
6818                 if (found_extent) {
6819                         BUG_ON(is_data && refs_to_drop !=
6820                                extent_data_ref_count(path, iref));
6821                         if (iref) {
6822                                 BUG_ON(path->slots[0] != extent_slot);
6823                         } else {
6824                                 BUG_ON(path->slots[0] != extent_slot + 1);
6825                                 path->slots[0] = extent_slot;
6826                                 num_to_del = 2;
6827                         }
6828                 }
6829
6830                 last_ref = 1;
6831                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6832                                       num_to_del);
6833                 if (ret) {
6834                         btrfs_abort_transaction(trans, extent_root, ret);
6835                         goto out;
6836                 }
6837                 btrfs_release_path(path);
6838
6839                 if (is_data) {
6840                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
6841                         if (ret) {
6842                                 btrfs_abort_transaction(trans, extent_root, ret);
6843                                 goto out;
6844                         }
6845                 }
6846
6847                 ret = add_to_free_space_tree(trans, root->fs_info, bytenr,
6848                                              num_bytes);
6849                 if (ret) {
6850                         btrfs_abort_transaction(trans, extent_root, ret);
6851                         goto out;
6852                 }
6853
6854                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
6855                 if (ret) {
6856                         btrfs_abort_transaction(trans, extent_root, ret);
6857                         goto out;
6858                 }
6859         }
6860         btrfs_release_path(path);
6861
6862 out:
6863         btrfs_free_path(path);
6864         return ret;
6865 }
6866
6867 /*
6868  * when we free an block, it is possible (and likely) that we free the last
6869  * delayed ref for that extent as well.  This searches the delayed ref tree for
6870  * a given extent, and if there are no other delayed refs to be processed, it
6871  * removes it from the tree.
6872  */
6873 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6874                                       struct btrfs_root *root, u64 bytenr)
6875 {
6876         struct btrfs_delayed_ref_head *head;
6877         struct btrfs_delayed_ref_root *delayed_refs;
6878         int ret = 0;
6879
6880         delayed_refs = &trans->transaction->delayed_refs;
6881         spin_lock(&delayed_refs->lock);
6882         head = btrfs_find_delayed_ref_head(trans, bytenr);
6883         if (!head)
6884                 goto out_delayed_unlock;
6885
6886         spin_lock(&head->lock);
6887         if (!list_empty(&head->ref_list))
6888                 goto out;
6889
6890         if (head->extent_op) {
6891                 if (!head->must_insert_reserved)
6892                         goto out;
6893                 btrfs_free_delayed_extent_op(head->extent_op);
6894                 head->extent_op = NULL;
6895         }
6896
6897         /*
6898          * waiting for the lock here would deadlock.  If someone else has it
6899          * locked they are already in the process of dropping it anyway
6900          */
6901         if (!mutex_trylock(&head->mutex))
6902                 goto out;
6903
6904         /*
6905          * at this point we have a head with no other entries.  Go
6906          * ahead and process it.
6907          */
6908         head->node.in_tree = 0;
6909         rb_erase(&head->href_node, &delayed_refs->href_root);
6910
6911         atomic_dec(&delayed_refs->num_entries);
6912
6913         /*
6914          * we don't take a ref on the node because we're removing it from the
6915          * tree, so we just steal the ref the tree was holding.
6916          */
6917         delayed_refs->num_heads--;
6918         if (head->processing == 0)
6919                 delayed_refs->num_heads_ready--;
6920         head->processing = 0;
6921         spin_unlock(&head->lock);
6922         spin_unlock(&delayed_refs->lock);
6923
6924         BUG_ON(head->extent_op);
6925         if (head->must_insert_reserved)
6926                 ret = 1;
6927
6928         mutex_unlock(&head->mutex);
6929         btrfs_put_delayed_ref(&head->node);
6930         return ret;
6931 out:
6932         spin_unlock(&head->lock);
6933
6934 out_delayed_unlock:
6935         spin_unlock(&delayed_refs->lock);
6936         return 0;
6937 }
6938
6939 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6940                            struct btrfs_root *root,
6941                            struct extent_buffer *buf,
6942                            u64 parent, int last_ref)
6943 {
6944         int pin = 1;
6945         int ret;
6946
6947         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6948                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6949                                         buf->start, buf->len,
6950                                         parent, root->root_key.objectid,
6951                                         btrfs_header_level(buf),
6952                                         BTRFS_DROP_DELAYED_REF, NULL);
6953                 BUG_ON(ret); /* -ENOMEM */
6954         }
6955
6956         if (!last_ref)
6957                 return;
6958
6959         if (btrfs_header_generation(buf) == trans->transid) {
6960                 struct btrfs_block_group_cache *cache;
6961
6962                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6963                         ret = check_ref_cleanup(trans, root, buf->start);
6964                         if (!ret)
6965                                 goto out;
6966                 }
6967
6968                 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6969
6970                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6971                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6972                         btrfs_put_block_group(cache);
6973                         goto out;
6974                 }
6975
6976                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6977
6978                 btrfs_add_free_space(cache, buf->start, buf->len);
6979                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
6980                 btrfs_put_block_group(cache);
6981                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6982                 pin = 0;
6983         }
6984 out:
6985         if (pin)
6986                 add_pinned_bytes(root->fs_info, buf->len,
6987                                  btrfs_header_level(buf),
6988                                  root->root_key.objectid);
6989
6990         /*
6991          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6992          * anymore.
6993          */
6994         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6995 }
6996
6997 /* Can return -ENOMEM */
6998 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6999                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7000                       u64 owner, u64 offset)
7001 {
7002         int ret;
7003         struct btrfs_fs_info *fs_info = root->fs_info;
7004
7005         if (btrfs_test_is_dummy_root(root))
7006                 return 0;
7007
7008         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
7009
7010         /*
7011          * tree log blocks never actually go into the extent allocation
7012          * tree, just update pinning info and exit early.
7013          */
7014         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7015                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7016                 /* unlocks the pinned mutex */
7017                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
7018                 ret = 0;
7019         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7020                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7021                                         num_bytes,
7022                                         parent, root_objectid, (int)owner,
7023                                         BTRFS_DROP_DELAYED_REF, NULL);
7024         } else {
7025                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7026                                                 num_bytes,
7027                                                 parent, root_objectid, owner,
7028                                                 offset, 0,
7029                                                 BTRFS_DROP_DELAYED_REF, NULL);
7030         }
7031         return ret;
7032 }
7033
7034 /*
7035  * when we wait for progress in the block group caching, its because
7036  * our allocation attempt failed at least once.  So, we must sleep
7037  * and let some progress happen before we try again.
7038  *
7039  * This function will sleep at least once waiting for new free space to
7040  * show up, and then it will check the block group free space numbers
7041  * for our min num_bytes.  Another option is to have it go ahead
7042  * and look in the rbtree for a free extent of a given size, but this
7043  * is a good start.
7044  *
7045  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7046  * any of the information in this block group.
7047  */
7048 static noinline void
7049 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7050                                 u64 num_bytes)
7051 {
7052         struct btrfs_caching_control *caching_ctl;
7053
7054         caching_ctl = get_caching_control(cache);
7055         if (!caching_ctl)
7056                 return;
7057
7058         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7059                    (cache->free_space_ctl->free_space >= num_bytes));
7060
7061         put_caching_control(caching_ctl);
7062 }
7063
7064 static noinline int
7065 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7066 {
7067         struct btrfs_caching_control *caching_ctl;
7068         int ret = 0;
7069
7070         caching_ctl = get_caching_control(cache);
7071         if (!caching_ctl)
7072                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7073
7074         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7075         if (cache->cached == BTRFS_CACHE_ERROR)
7076                 ret = -EIO;
7077         put_caching_control(caching_ctl);
7078         return ret;
7079 }
7080
7081 int __get_raid_index(u64 flags)
7082 {
7083         if (flags & BTRFS_BLOCK_GROUP_RAID10)
7084                 return BTRFS_RAID_RAID10;
7085         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
7086                 return BTRFS_RAID_RAID1;
7087         else if (flags & BTRFS_BLOCK_GROUP_DUP)
7088                 return BTRFS_RAID_DUP;
7089         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
7090                 return BTRFS_RAID_RAID0;
7091         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
7092                 return BTRFS_RAID_RAID5;
7093         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
7094                 return BTRFS_RAID_RAID6;
7095
7096         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
7097 }
7098
7099 int get_block_group_index(struct btrfs_block_group_cache *cache)
7100 {
7101         return __get_raid_index(cache->flags);
7102 }
7103
7104 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7105         [BTRFS_RAID_RAID10]     = "raid10",
7106         [BTRFS_RAID_RAID1]      = "raid1",
7107         [BTRFS_RAID_DUP]        = "dup",
7108         [BTRFS_RAID_RAID0]      = "raid0",
7109         [BTRFS_RAID_SINGLE]     = "single",
7110         [BTRFS_RAID_RAID5]      = "raid5",
7111         [BTRFS_RAID_RAID6]      = "raid6",
7112 };
7113
7114 static const char *get_raid_name(enum btrfs_raid_types type)
7115 {
7116         if (type >= BTRFS_NR_RAID_TYPES)
7117                 return NULL;
7118
7119         return btrfs_raid_type_names[type];
7120 }
7121
7122 enum btrfs_loop_type {
7123         LOOP_CACHING_NOWAIT = 0,
7124         LOOP_CACHING_WAIT = 1,
7125         LOOP_ALLOC_CHUNK = 2,
7126         LOOP_NO_EMPTY_SIZE = 3,
7127 };
7128
7129 static inline void
7130 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7131                        int delalloc)
7132 {
7133         if (delalloc)
7134                 down_read(&cache->data_rwsem);
7135 }
7136
7137 static inline void
7138 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7139                        int delalloc)
7140 {
7141         btrfs_get_block_group(cache);
7142         if (delalloc)
7143                 down_read(&cache->data_rwsem);
7144 }
7145
7146 static struct btrfs_block_group_cache *
7147 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7148                    struct btrfs_free_cluster *cluster,
7149                    int delalloc)
7150 {
7151         struct btrfs_block_group_cache *used_bg = NULL;
7152
7153         spin_lock(&cluster->refill_lock);
7154         while (1) {
7155                 used_bg = cluster->block_group;
7156                 if (!used_bg)
7157                         return NULL;
7158
7159                 if (used_bg == block_group)
7160                         return used_bg;
7161
7162                 btrfs_get_block_group(used_bg);
7163
7164                 if (!delalloc)
7165                         return used_bg;
7166
7167                 if (down_read_trylock(&used_bg->data_rwsem))
7168                         return used_bg;
7169
7170                 spin_unlock(&cluster->refill_lock);
7171
7172                 down_read(&used_bg->data_rwsem);
7173
7174                 spin_lock(&cluster->refill_lock);
7175                 if (used_bg == cluster->block_group)
7176                         return used_bg;
7177
7178                 up_read(&used_bg->data_rwsem);
7179                 btrfs_put_block_group(used_bg);
7180         }
7181 }
7182
7183 static inline void
7184 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7185                          int delalloc)
7186 {
7187         if (delalloc)
7188                 up_read(&cache->data_rwsem);
7189         btrfs_put_block_group(cache);
7190 }
7191
7192 /*
7193  * walks the btree of allocated extents and find a hole of a given size.
7194  * The key ins is changed to record the hole:
7195  * ins->objectid == start position
7196  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7197  * ins->offset == the size of the hole.
7198  * Any available blocks before search_start are skipped.
7199  *
7200  * If there is no suitable free space, we will record the max size of
7201  * the free space extent currently.
7202  */
7203 static noinline int find_free_extent(struct btrfs_root *orig_root,
7204                                      u64 num_bytes, u64 empty_size,
7205                                      u64 hint_byte, struct btrfs_key *ins,
7206                                      u64 flags, int delalloc)
7207 {
7208         int ret = 0;
7209         struct btrfs_root *root = orig_root->fs_info->extent_root;
7210         struct btrfs_free_cluster *last_ptr = NULL;
7211         struct btrfs_block_group_cache *block_group = NULL;
7212         u64 search_start = 0;
7213         u64 max_extent_size = 0;
7214         u64 empty_cluster = 0;
7215         struct btrfs_space_info *space_info;
7216         int loop = 0;
7217         int index = __get_raid_index(flags);
7218         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
7219                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
7220         bool failed_cluster_refill = false;
7221         bool failed_alloc = false;
7222         bool use_cluster = true;
7223         bool have_caching_bg = false;
7224         bool orig_have_caching_bg = false;
7225         bool full_search = false;
7226
7227         WARN_ON(num_bytes < root->sectorsize);
7228         ins->type = BTRFS_EXTENT_ITEM_KEY;
7229         ins->objectid = 0;
7230         ins->offset = 0;
7231
7232         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
7233
7234         space_info = __find_space_info(root->fs_info, flags);
7235         if (!space_info) {
7236                 btrfs_err(root->fs_info, "No space info for %llu", flags);
7237                 return -ENOSPC;
7238         }
7239
7240         /*
7241          * If our free space is heavily fragmented we may not be able to make
7242          * big contiguous allocations, so instead of doing the expensive search
7243          * for free space, simply return ENOSPC with our max_extent_size so we
7244          * can go ahead and search for a more manageable chunk.
7245          *
7246          * If our max_extent_size is large enough for our allocation simply
7247          * disable clustering since we will likely not be able to find enough
7248          * space to create a cluster and induce latency trying.
7249          */
7250         if (unlikely(space_info->max_extent_size)) {
7251                 spin_lock(&space_info->lock);
7252                 if (space_info->max_extent_size &&
7253                     num_bytes > space_info->max_extent_size) {
7254                         ins->offset = space_info->max_extent_size;
7255                         spin_unlock(&space_info->lock);
7256                         return -ENOSPC;
7257                 } else if (space_info->max_extent_size) {
7258                         use_cluster = false;
7259                 }
7260                 spin_unlock(&space_info->lock);
7261         }
7262
7263         last_ptr = fetch_cluster_info(orig_root, space_info, &empty_cluster);
7264         if (last_ptr) {
7265                 spin_lock(&last_ptr->lock);
7266                 if (last_ptr->block_group)
7267                         hint_byte = last_ptr->window_start;
7268                 if (last_ptr->fragmented) {
7269                         /*
7270                          * We still set window_start so we can keep track of the
7271                          * last place we found an allocation to try and save
7272                          * some time.
7273                          */
7274                         hint_byte = last_ptr->window_start;
7275                         use_cluster = false;
7276                 }
7277                 spin_unlock(&last_ptr->lock);
7278         }
7279
7280         search_start = max(search_start, first_logical_byte(root, 0));
7281         search_start = max(search_start, hint_byte);
7282         if (search_start == hint_byte) {
7283                 block_group = btrfs_lookup_block_group(root->fs_info,
7284                                                        search_start);
7285                 /*
7286                  * we don't want to use the block group if it doesn't match our
7287                  * allocation bits, or if its not cached.
7288                  *
7289                  * However if we are re-searching with an ideal block group
7290                  * picked out then we don't care that the block group is cached.
7291                  */
7292                 if (block_group && block_group_bits(block_group, flags) &&
7293                     block_group->cached != BTRFS_CACHE_NO) {
7294                         down_read(&space_info->groups_sem);
7295                         if (list_empty(&block_group->list) ||
7296                             block_group->ro) {
7297                                 /*
7298                                  * someone is removing this block group,
7299                                  * we can't jump into the have_block_group
7300                                  * target because our list pointers are not
7301                                  * valid
7302                                  */
7303                                 btrfs_put_block_group(block_group);
7304                                 up_read(&space_info->groups_sem);
7305                         } else {
7306                                 index = get_block_group_index(block_group);
7307                                 btrfs_lock_block_group(block_group, delalloc);
7308                                 goto have_block_group;
7309                         }
7310                 } else if (block_group) {
7311                         btrfs_put_block_group(block_group);
7312                 }
7313         }
7314 search:
7315         have_caching_bg = false;
7316         if (index == 0 || index == __get_raid_index(flags))
7317                 full_search = true;
7318         down_read(&space_info->groups_sem);
7319         list_for_each_entry(block_group, &space_info->block_groups[index],
7320                             list) {
7321                 u64 offset;
7322                 int cached;
7323
7324                 btrfs_grab_block_group(block_group, delalloc);
7325                 search_start = block_group->key.objectid;
7326
7327                 /*
7328                  * this can happen if we end up cycling through all the
7329                  * raid types, but we want to make sure we only allocate
7330                  * for the proper type.
7331                  */
7332                 if (!block_group_bits(block_group, flags)) {
7333                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7334                                 BTRFS_BLOCK_GROUP_RAID1 |
7335                                 BTRFS_BLOCK_GROUP_RAID5 |
7336                                 BTRFS_BLOCK_GROUP_RAID6 |
7337                                 BTRFS_BLOCK_GROUP_RAID10;
7338
7339                         /*
7340                          * if they asked for extra copies and this block group
7341                          * doesn't provide them, bail.  This does allow us to
7342                          * fill raid0 from raid1.
7343                          */
7344                         if ((flags & extra) && !(block_group->flags & extra))
7345                                 goto loop;
7346                 }
7347
7348 have_block_group:
7349                 cached = block_group_cache_done(block_group);
7350                 if (unlikely(!cached)) {
7351                         have_caching_bg = true;
7352                         ret = cache_block_group(block_group, 0);
7353                         BUG_ON(ret < 0);
7354                         ret = 0;
7355                 }
7356
7357                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7358                         goto loop;
7359                 if (unlikely(block_group->ro))
7360                         goto loop;
7361
7362                 /*
7363                  * Ok we want to try and use the cluster allocator, so
7364                  * lets look there
7365                  */
7366                 if (last_ptr && use_cluster) {
7367                         struct btrfs_block_group_cache *used_block_group;
7368                         unsigned long aligned_cluster;
7369                         /*
7370                          * the refill lock keeps out other
7371                          * people trying to start a new cluster
7372                          */
7373                         used_block_group = btrfs_lock_cluster(block_group,
7374                                                               last_ptr,
7375                                                               delalloc);
7376                         if (!used_block_group)
7377                                 goto refill_cluster;
7378
7379                         if (used_block_group != block_group &&
7380                             (used_block_group->ro ||
7381                              !block_group_bits(used_block_group, flags)))
7382                                 goto release_cluster;
7383
7384                         offset = btrfs_alloc_from_cluster(used_block_group,
7385                                                 last_ptr,
7386                                                 num_bytes,
7387                                                 used_block_group->key.objectid,
7388                                                 &max_extent_size);
7389                         if (offset) {
7390                                 /* we have a block, we're done */
7391                                 spin_unlock(&last_ptr->refill_lock);
7392                                 trace_btrfs_reserve_extent_cluster(root,
7393                                                 used_block_group,
7394                                                 search_start, num_bytes);
7395                                 if (used_block_group != block_group) {
7396                                         btrfs_release_block_group(block_group,
7397                                                                   delalloc);
7398                                         block_group = used_block_group;
7399                                 }
7400                                 goto checks;
7401                         }
7402
7403                         WARN_ON(last_ptr->block_group != used_block_group);
7404 release_cluster:
7405                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7406                          * set up a new clusters, so lets just skip it
7407                          * and let the allocator find whatever block
7408                          * it can find.  If we reach this point, we
7409                          * will have tried the cluster allocator
7410                          * plenty of times and not have found
7411                          * anything, so we are likely way too
7412                          * fragmented for the clustering stuff to find
7413                          * anything.
7414                          *
7415                          * However, if the cluster is taken from the
7416                          * current block group, release the cluster
7417                          * first, so that we stand a better chance of
7418                          * succeeding in the unclustered
7419                          * allocation.  */
7420                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7421                             used_block_group != block_group) {
7422                                 spin_unlock(&last_ptr->refill_lock);
7423                                 btrfs_release_block_group(used_block_group,
7424                                                           delalloc);
7425                                 goto unclustered_alloc;
7426                         }
7427
7428                         /*
7429                          * this cluster didn't work out, free it and
7430                          * start over
7431                          */
7432                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7433
7434                         if (used_block_group != block_group)
7435                                 btrfs_release_block_group(used_block_group,
7436                                                           delalloc);
7437 refill_cluster:
7438                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7439                                 spin_unlock(&last_ptr->refill_lock);
7440                                 goto unclustered_alloc;
7441                         }
7442
7443                         aligned_cluster = max_t(unsigned long,
7444                                                 empty_cluster + empty_size,
7445                                               block_group->full_stripe_len);
7446
7447                         /* allocate a cluster in this block group */
7448                         ret = btrfs_find_space_cluster(root, block_group,
7449                                                        last_ptr, search_start,
7450                                                        num_bytes,
7451                                                        aligned_cluster);
7452                         if (ret == 0) {
7453                                 /*
7454                                  * now pull our allocation out of this
7455                                  * cluster
7456                                  */
7457                                 offset = btrfs_alloc_from_cluster(block_group,
7458                                                         last_ptr,
7459                                                         num_bytes,
7460                                                         search_start,
7461                                                         &max_extent_size);
7462                                 if (offset) {
7463                                         /* we found one, proceed */
7464                                         spin_unlock(&last_ptr->refill_lock);
7465                                         trace_btrfs_reserve_extent_cluster(root,
7466                                                 block_group, search_start,
7467                                                 num_bytes);
7468                                         goto checks;
7469                                 }
7470                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7471                                    && !failed_cluster_refill) {
7472                                 spin_unlock(&last_ptr->refill_lock);
7473
7474                                 failed_cluster_refill = true;
7475                                 wait_block_group_cache_progress(block_group,
7476                                        num_bytes + empty_cluster + empty_size);
7477                                 goto have_block_group;
7478                         }
7479
7480                         /*
7481                          * at this point we either didn't find a cluster
7482                          * or we weren't able to allocate a block from our
7483                          * cluster.  Free the cluster we've been trying
7484                          * to use, and go to the next block group
7485                          */
7486                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7487                         spin_unlock(&last_ptr->refill_lock);
7488                         goto loop;
7489                 }
7490
7491 unclustered_alloc:
7492                 /*
7493                  * We are doing an unclustered alloc, set the fragmented flag so
7494                  * we don't bother trying to setup a cluster again until we get
7495                  * more space.
7496                  */
7497                 if (unlikely(last_ptr)) {
7498                         spin_lock(&last_ptr->lock);
7499                         last_ptr->fragmented = 1;
7500                         spin_unlock(&last_ptr->lock);
7501                 }
7502                 spin_lock(&block_group->free_space_ctl->tree_lock);
7503                 if (cached &&
7504                     block_group->free_space_ctl->free_space <
7505                     num_bytes + empty_cluster + empty_size) {
7506                         if (block_group->free_space_ctl->free_space >
7507                             max_extent_size)
7508                                 max_extent_size =
7509                                         block_group->free_space_ctl->free_space;
7510                         spin_unlock(&block_group->free_space_ctl->tree_lock);
7511                         goto loop;
7512                 }
7513                 spin_unlock(&block_group->free_space_ctl->tree_lock);
7514
7515                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7516                                                     num_bytes, empty_size,
7517                                                     &max_extent_size);
7518                 /*
7519                  * If we didn't find a chunk, and we haven't failed on this
7520                  * block group before, and this block group is in the middle of
7521                  * caching and we are ok with waiting, then go ahead and wait
7522                  * for progress to be made, and set failed_alloc to true.
7523                  *
7524                  * If failed_alloc is true then we've already waited on this
7525                  * block group once and should move on to the next block group.
7526                  */
7527                 if (!offset && !failed_alloc && !cached &&
7528                     loop > LOOP_CACHING_NOWAIT) {
7529                         wait_block_group_cache_progress(block_group,
7530                                                 num_bytes + empty_size);
7531                         failed_alloc = true;
7532                         goto have_block_group;
7533                 } else if (!offset) {
7534                         goto loop;
7535                 }
7536 checks:
7537                 search_start = ALIGN(offset, root->stripesize);
7538
7539                 /* move on to the next group */
7540                 if (search_start + num_bytes >
7541                     block_group->key.objectid + block_group->key.offset) {
7542                         btrfs_add_free_space(block_group, offset, num_bytes);
7543                         goto loop;
7544                 }
7545
7546                 if (offset < search_start)
7547                         btrfs_add_free_space(block_group, offset,
7548                                              search_start - offset);
7549                 BUG_ON(offset > search_start);
7550
7551                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
7552                                                   alloc_type, delalloc);
7553                 if (ret == -EAGAIN) {
7554                         btrfs_add_free_space(block_group, offset, num_bytes);
7555                         goto loop;
7556                 }
7557                 btrfs_inc_block_group_reservations(block_group);
7558
7559                 /* we are all good, lets return */
7560                 ins->objectid = search_start;
7561                 ins->offset = num_bytes;
7562
7563                 trace_btrfs_reserve_extent(orig_root, block_group,
7564                                            search_start, num_bytes);
7565                 btrfs_release_block_group(block_group, delalloc);
7566                 break;
7567 loop:
7568                 failed_cluster_refill = false;
7569                 failed_alloc = false;
7570                 BUG_ON(index != get_block_group_index(block_group));
7571                 btrfs_release_block_group(block_group, delalloc);
7572         }
7573         up_read(&space_info->groups_sem);
7574
7575         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7576                 && !orig_have_caching_bg)
7577                 orig_have_caching_bg = true;
7578
7579         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7580                 goto search;
7581
7582         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7583                 goto search;
7584
7585         /*
7586          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7587          *                      caching kthreads as we move along
7588          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7589          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7590          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7591          *                      again
7592          */
7593         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7594                 index = 0;
7595                 if (loop == LOOP_CACHING_NOWAIT) {
7596                         /*
7597                          * We want to skip the LOOP_CACHING_WAIT step if we
7598                          * don't have any uncached bgs and we've already done a
7599                          * full search through.
7600                          */
7601                         if (orig_have_caching_bg || !full_search)
7602                                 loop = LOOP_CACHING_WAIT;
7603                         else
7604                                 loop = LOOP_ALLOC_CHUNK;
7605                 } else {
7606                         loop++;
7607                 }
7608
7609                 if (loop == LOOP_ALLOC_CHUNK) {
7610                         struct btrfs_trans_handle *trans;
7611                         int exist = 0;
7612
7613                         trans = current->journal_info;
7614                         if (trans)
7615                                 exist = 1;
7616                         else
7617                                 trans = btrfs_join_transaction(root);
7618
7619                         if (IS_ERR(trans)) {
7620                                 ret = PTR_ERR(trans);
7621                                 goto out;
7622                         }
7623
7624                         ret = do_chunk_alloc(trans, root, flags,
7625                                              CHUNK_ALLOC_FORCE);
7626
7627                         /*
7628                          * If we can't allocate a new chunk we've already looped
7629                          * through at least once, move on to the NO_EMPTY_SIZE
7630                          * case.
7631                          */
7632                         if (ret == -ENOSPC)
7633                                 loop = LOOP_NO_EMPTY_SIZE;
7634
7635                         /*
7636                          * Do not bail out on ENOSPC since we
7637                          * can do more things.
7638                          */
7639                         if (ret < 0 && ret != -ENOSPC)
7640                                 btrfs_abort_transaction(trans,
7641                                                         root, ret);
7642                         else
7643                                 ret = 0;
7644                         if (!exist)
7645                                 btrfs_end_transaction(trans, root);
7646                         if (ret)
7647                                 goto out;
7648                 }
7649
7650                 if (loop == LOOP_NO_EMPTY_SIZE) {
7651                         /*
7652                          * Don't loop again if we already have no empty_size and
7653                          * no empty_cluster.
7654                          */
7655                         if (empty_size == 0 &&
7656                             empty_cluster == 0) {
7657                                 ret = -ENOSPC;
7658                                 goto out;
7659                         }
7660                         empty_size = 0;
7661                         empty_cluster = 0;
7662                 }
7663
7664                 goto search;
7665         } else if (!ins->objectid) {
7666                 ret = -ENOSPC;
7667         } else if (ins->objectid) {
7668                 if (!use_cluster && last_ptr) {
7669                         spin_lock(&last_ptr->lock);
7670                         last_ptr->window_start = ins->objectid;
7671                         spin_unlock(&last_ptr->lock);
7672                 }
7673                 ret = 0;
7674         }
7675 out:
7676         if (ret == -ENOSPC) {
7677                 spin_lock(&space_info->lock);
7678                 space_info->max_extent_size = max_extent_size;
7679                 spin_unlock(&space_info->lock);
7680                 ins->offset = max_extent_size;
7681         }
7682         return ret;
7683 }
7684
7685 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7686                             int dump_block_groups)
7687 {
7688         struct btrfs_block_group_cache *cache;
7689         int index = 0;
7690
7691         spin_lock(&info->lock);
7692         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7693                info->flags,
7694                info->total_bytes - info->bytes_used - info->bytes_pinned -
7695                info->bytes_reserved - info->bytes_readonly,
7696                (info->full) ? "" : "not ");
7697         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7698                "reserved=%llu, may_use=%llu, readonly=%llu\n",
7699                info->total_bytes, info->bytes_used, info->bytes_pinned,
7700                info->bytes_reserved, info->bytes_may_use,
7701                info->bytes_readonly);
7702         spin_unlock(&info->lock);
7703
7704         if (!dump_block_groups)
7705                 return;
7706
7707         down_read(&info->groups_sem);
7708 again:
7709         list_for_each_entry(cache, &info->block_groups[index], list) {
7710                 spin_lock(&cache->lock);
7711                 printk(KERN_INFO "BTRFS: "
7712                            "block group %llu has %llu bytes, "
7713                            "%llu used %llu pinned %llu reserved %s\n",
7714                        cache->key.objectid, cache->key.offset,
7715                        btrfs_block_group_used(&cache->item), cache->pinned,
7716                        cache->reserved, cache->ro ? "[readonly]" : "");
7717                 btrfs_dump_free_space(cache, bytes);
7718                 spin_unlock(&cache->lock);
7719         }
7720         if (++index < BTRFS_NR_RAID_TYPES)
7721                 goto again;
7722         up_read(&info->groups_sem);
7723 }
7724
7725 int btrfs_reserve_extent(struct btrfs_root *root,
7726                          u64 num_bytes, u64 min_alloc_size,
7727                          u64 empty_size, u64 hint_byte,
7728                          struct btrfs_key *ins, int is_data, int delalloc)
7729 {
7730         bool final_tried = num_bytes == min_alloc_size;
7731         u64 flags;
7732         int ret;
7733
7734         flags = btrfs_get_alloc_profile(root, is_data);
7735 again:
7736         WARN_ON(num_bytes < root->sectorsize);
7737         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
7738                                flags, delalloc);
7739         if (!ret && !is_data) {
7740                 btrfs_dec_block_group_reservations(root->fs_info,
7741                                                    ins->objectid);
7742         } else if (ret == -ENOSPC) {
7743                 if (!final_tried && ins->offset) {
7744                         num_bytes = min(num_bytes >> 1, ins->offset);
7745                         num_bytes = round_down(num_bytes, root->sectorsize);
7746                         num_bytes = max(num_bytes, min_alloc_size);
7747                         if (num_bytes == min_alloc_size)
7748                                 final_tried = true;
7749                         goto again;
7750                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7751                         struct btrfs_space_info *sinfo;
7752
7753                         sinfo = __find_space_info(root->fs_info, flags);
7754                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7755                                 flags, num_bytes);
7756                         if (sinfo)
7757                                 dump_space_info(sinfo, num_bytes, 1);
7758                 }
7759         }
7760
7761         return ret;
7762 }
7763
7764 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7765                                         u64 start, u64 len,
7766                                         int pin, int delalloc)
7767 {
7768         struct btrfs_block_group_cache *cache;
7769         int ret = 0;
7770
7771         cache = btrfs_lookup_block_group(root->fs_info, start);
7772         if (!cache) {
7773                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7774                         start);
7775                 return -ENOSPC;
7776         }
7777
7778         if (pin)
7779                 pin_down_extent(root, cache, start, len, 1);
7780         else {
7781                 if (btrfs_test_opt(root, DISCARD))
7782                         ret = btrfs_discard_extent(root, start, len, NULL);
7783                 btrfs_add_free_space(cache, start, len);
7784                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
7785         }
7786
7787         btrfs_put_block_group(cache);
7788
7789         trace_btrfs_reserved_extent_free(root, start, len);
7790
7791         return ret;
7792 }
7793
7794 int btrfs_free_reserved_extent(struct btrfs_root *root,
7795                                u64 start, u64 len, int delalloc)
7796 {
7797         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
7798 }
7799
7800 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
7801                                        u64 start, u64 len)
7802 {
7803         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
7804 }
7805
7806 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7807                                       struct btrfs_root *root,
7808                                       u64 parent, u64 root_objectid,
7809                                       u64 flags, u64 owner, u64 offset,
7810                                       struct btrfs_key *ins, int ref_mod)
7811 {
7812         int ret;
7813         struct btrfs_fs_info *fs_info = root->fs_info;
7814         struct btrfs_extent_item *extent_item;
7815         struct btrfs_extent_inline_ref *iref;
7816         struct btrfs_path *path;
7817         struct extent_buffer *leaf;
7818         int type;
7819         u32 size;
7820
7821         if (parent > 0)
7822                 type = BTRFS_SHARED_DATA_REF_KEY;
7823         else
7824                 type = BTRFS_EXTENT_DATA_REF_KEY;
7825
7826         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7827
7828         path = btrfs_alloc_path();
7829         if (!path)
7830                 return -ENOMEM;
7831
7832         path->leave_spinning = 1;
7833         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7834                                       ins, size);
7835         if (ret) {
7836                 btrfs_free_path(path);
7837                 return ret;
7838         }
7839
7840         leaf = path->nodes[0];
7841         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7842                                      struct btrfs_extent_item);
7843         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7844         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7845         btrfs_set_extent_flags(leaf, extent_item,
7846                                flags | BTRFS_EXTENT_FLAG_DATA);
7847
7848         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7849         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7850         if (parent > 0) {
7851                 struct btrfs_shared_data_ref *ref;
7852                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7853                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7854                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7855         } else {
7856                 struct btrfs_extent_data_ref *ref;
7857                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7858                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7859                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7860                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7861                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7862         }
7863
7864         btrfs_mark_buffer_dirty(path->nodes[0]);
7865         btrfs_free_path(path);
7866
7867         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
7868                                           ins->offset);
7869         if (ret)
7870                 return ret;
7871
7872         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
7873         if (ret) { /* -ENOENT, logic error */
7874                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7875                         ins->objectid, ins->offset);
7876                 BUG();
7877         }
7878         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
7879         return ret;
7880 }
7881
7882 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7883                                      struct btrfs_root *root,
7884                                      u64 parent, u64 root_objectid,
7885                                      u64 flags, struct btrfs_disk_key *key,
7886                                      int level, struct btrfs_key *ins)
7887 {
7888         int ret;
7889         struct btrfs_fs_info *fs_info = root->fs_info;
7890         struct btrfs_extent_item *extent_item;
7891         struct btrfs_tree_block_info *block_info;
7892         struct btrfs_extent_inline_ref *iref;
7893         struct btrfs_path *path;
7894         struct extent_buffer *leaf;
7895         u32 size = sizeof(*extent_item) + sizeof(*iref);
7896         u64 num_bytes = ins->offset;
7897         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7898                                                  SKINNY_METADATA);
7899
7900         if (!skinny_metadata)
7901                 size += sizeof(*block_info);
7902
7903         path = btrfs_alloc_path();
7904         if (!path) {
7905                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7906                                                    root->nodesize);
7907                 return -ENOMEM;
7908         }
7909
7910         path->leave_spinning = 1;
7911         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7912                                       ins, size);
7913         if (ret) {
7914                 btrfs_free_path(path);
7915                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7916                                                    root->nodesize);
7917                 return ret;
7918         }
7919
7920         leaf = path->nodes[0];
7921         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7922                                      struct btrfs_extent_item);
7923         btrfs_set_extent_refs(leaf, extent_item, 1);
7924         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7925         btrfs_set_extent_flags(leaf, extent_item,
7926                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
7927
7928         if (skinny_metadata) {
7929                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7930                 num_bytes = root->nodesize;
7931         } else {
7932                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
7933                 btrfs_set_tree_block_key(leaf, block_info, key);
7934                 btrfs_set_tree_block_level(leaf, block_info, level);
7935                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
7936         }
7937
7938         if (parent > 0) {
7939                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
7940                 btrfs_set_extent_inline_ref_type(leaf, iref,
7941                                                  BTRFS_SHARED_BLOCK_REF_KEY);
7942                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7943         } else {
7944                 btrfs_set_extent_inline_ref_type(leaf, iref,
7945                                                  BTRFS_TREE_BLOCK_REF_KEY);
7946                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
7947         }
7948
7949         btrfs_mark_buffer_dirty(leaf);
7950         btrfs_free_path(path);
7951
7952         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
7953                                           num_bytes);
7954         if (ret)
7955                 return ret;
7956
7957         ret = update_block_group(trans, root, ins->objectid, root->nodesize,
7958                                  1);
7959         if (ret) { /* -ENOENT, logic error */
7960                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7961                         ins->objectid, ins->offset);
7962                 BUG();
7963         }
7964
7965         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
7966         return ret;
7967 }
7968
7969 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7970                                      struct btrfs_root *root,
7971                                      u64 root_objectid, u64 owner,
7972                                      u64 offset, u64 ram_bytes,
7973                                      struct btrfs_key *ins)
7974 {
7975         int ret;
7976
7977         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
7978
7979         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
7980                                          ins->offset, 0,
7981                                          root_objectid, owner, offset,
7982                                          ram_bytes, BTRFS_ADD_DELAYED_EXTENT,
7983                                          NULL);
7984         return ret;
7985 }
7986
7987 /*
7988  * this is used by the tree logging recovery code.  It records that
7989  * an extent has been allocated and makes sure to clear the free
7990  * space cache bits as well
7991  */
7992 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
7993                                    struct btrfs_root *root,
7994                                    u64 root_objectid, u64 owner, u64 offset,
7995                                    struct btrfs_key *ins)
7996 {
7997         int ret;
7998         struct btrfs_block_group_cache *block_group;
7999
8000         /*
8001          * Mixed block groups will exclude before processing the log so we only
8002          * need to do the exclude dance if this fs isn't mixed.
8003          */
8004         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
8005                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
8006                 if (ret)
8007                         return ret;
8008         }
8009
8010         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
8011         if (!block_group)
8012                 return -EINVAL;
8013
8014         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
8015                                           RESERVE_ALLOC_NO_ACCOUNT, 0);
8016         BUG_ON(ret); /* logic error */
8017         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
8018                                          0, owner, offset, ins, 1);
8019         btrfs_put_block_group(block_group);
8020         return ret;
8021 }
8022
8023 static struct extent_buffer *
8024 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8025                       u64 bytenr, int level)
8026 {
8027         struct extent_buffer *buf;
8028
8029         buf = btrfs_find_create_tree_block(root, bytenr);
8030         if (IS_ERR(buf))
8031                 return buf;
8032
8033         btrfs_set_header_generation(buf, trans->transid);
8034         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8035         btrfs_tree_lock(buf);
8036         clean_tree_block(trans, root->fs_info, buf);
8037         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8038
8039         btrfs_set_lock_blocking(buf);
8040         set_extent_buffer_uptodate(buf);
8041
8042         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8043                 buf->log_index = root->log_transid % 2;
8044                 /*
8045                  * we allow two log transactions at a time, use different
8046                  * EXENT bit to differentiate dirty pages.
8047                  */
8048                 if (buf->log_index == 0)
8049                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8050                                         buf->start + buf->len - 1, GFP_NOFS);
8051                 else
8052                         set_extent_new(&root->dirty_log_pages, buf->start,
8053                                         buf->start + buf->len - 1);
8054         } else {
8055                 buf->log_index = -1;
8056                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8057                          buf->start + buf->len - 1, GFP_NOFS);
8058         }
8059         trans->dirty = true;
8060         /* this returns a buffer locked for blocking */
8061         return buf;
8062 }
8063
8064 static struct btrfs_block_rsv *
8065 use_block_rsv(struct btrfs_trans_handle *trans,
8066               struct btrfs_root *root, u32 blocksize)
8067 {
8068         struct btrfs_block_rsv *block_rsv;
8069         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
8070         int ret;
8071         bool global_updated = false;
8072
8073         block_rsv = get_block_rsv(trans, root);
8074
8075         if (unlikely(block_rsv->size == 0))
8076                 goto try_reserve;
8077 again:
8078         ret = block_rsv_use_bytes(block_rsv, blocksize);
8079         if (!ret)
8080                 return block_rsv;
8081
8082         if (block_rsv->failfast)
8083                 return ERR_PTR(ret);
8084
8085         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8086                 global_updated = true;
8087                 update_global_block_rsv(root->fs_info);
8088                 goto again;
8089         }
8090
8091         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
8092                 static DEFINE_RATELIMIT_STATE(_rs,
8093                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8094                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8095                 if (__ratelimit(&_rs))
8096                         WARN(1, KERN_DEBUG
8097                                 "BTRFS: block rsv returned %d\n", ret);
8098         }
8099 try_reserve:
8100         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8101                                      BTRFS_RESERVE_NO_FLUSH);
8102         if (!ret)
8103                 return block_rsv;
8104         /*
8105          * If we couldn't reserve metadata bytes try and use some from
8106          * the global reserve if its space type is the same as the global
8107          * reservation.
8108          */
8109         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8110             block_rsv->space_info == global_rsv->space_info) {
8111                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8112                 if (!ret)
8113                         return global_rsv;
8114         }
8115         return ERR_PTR(ret);
8116 }
8117
8118 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8119                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8120 {
8121         block_rsv_add_bytes(block_rsv, blocksize, 0);
8122         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8123 }
8124
8125 /*
8126  * finds a free extent and does all the dirty work required for allocation
8127  * returns the tree buffer or an ERR_PTR on error.
8128  */
8129 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8130                                         struct btrfs_root *root,
8131                                         u64 parent, u64 root_objectid,
8132                                         struct btrfs_disk_key *key, int level,
8133                                         u64 hint, u64 empty_size)
8134 {
8135         struct btrfs_key ins;
8136         struct btrfs_block_rsv *block_rsv;
8137         struct extent_buffer *buf;
8138         struct btrfs_delayed_extent_op *extent_op;
8139         u64 flags = 0;
8140         int ret;
8141         u32 blocksize = root->nodesize;
8142         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
8143                                                  SKINNY_METADATA);
8144
8145         if (btrfs_test_is_dummy_root(root)) {
8146                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8147                                             level);
8148                 if (!IS_ERR(buf))
8149                         root->alloc_bytenr += blocksize;
8150                 return buf;
8151         }
8152
8153         block_rsv = use_block_rsv(trans, root, blocksize);
8154         if (IS_ERR(block_rsv))
8155                 return ERR_CAST(block_rsv);
8156
8157         ret = btrfs_reserve_extent(root, blocksize, blocksize,
8158                                    empty_size, hint, &ins, 0, 0);
8159         if (ret)
8160                 goto out_unuse;
8161
8162         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8163         if (IS_ERR(buf)) {
8164                 ret = PTR_ERR(buf);
8165                 goto out_free_reserved;
8166         }
8167
8168         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8169                 if (parent == 0)
8170                         parent = ins.objectid;
8171                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8172         } else
8173                 BUG_ON(parent > 0);
8174
8175         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8176                 extent_op = btrfs_alloc_delayed_extent_op();
8177                 if (!extent_op) {
8178                         ret = -ENOMEM;
8179                         goto out_free_buf;
8180                 }
8181                 if (key)
8182                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8183                 else
8184                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8185                 extent_op->flags_to_set = flags;
8186                 extent_op->update_key = skinny_metadata ? false : true;
8187                 extent_op->update_flags = true;
8188                 extent_op->is_data = false;
8189                 extent_op->level = level;
8190
8191                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
8192                                                  ins.objectid, ins.offset,
8193                                                  parent, root_objectid, level,
8194                                                  BTRFS_ADD_DELAYED_EXTENT,
8195                                                  extent_op);
8196                 if (ret)
8197                         goto out_free_delayed;
8198         }
8199         return buf;
8200
8201 out_free_delayed:
8202         btrfs_free_delayed_extent_op(extent_op);
8203 out_free_buf:
8204         free_extent_buffer(buf);
8205 out_free_reserved:
8206         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
8207 out_unuse:
8208         unuse_block_rsv(root->fs_info, block_rsv, blocksize);
8209         return ERR_PTR(ret);
8210 }
8211
8212 struct walk_control {
8213         u64 refs[BTRFS_MAX_LEVEL];
8214         u64 flags[BTRFS_MAX_LEVEL];
8215         struct btrfs_key update_progress;
8216         int stage;
8217         int level;
8218         int shared_level;
8219         int update_ref;
8220         int keep_locks;
8221         int reada_slot;
8222         int reada_count;
8223         int for_reloc;
8224 };
8225
8226 #define DROP_REFERENCE  1
8227 #define UPDATE_BACKREF  2
8228
8229 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8230                                      struct btrfs_root *root,
8231                                      struct walk_control *wc,
8232                                      struct btrfs_path *path)
8233 {
8234         u64 bytenr;
8235         u64 generation;
8236         u64 refs;
8237         u64 flags;
8238         u32 nritems;
8239         u32 blocksize;
8240         struct btrfs_key key;
8241         struct extent_buffer *eb;
8242         int ret;
8243         int slot;
8244         int nread = 0;
8245
8246         if (path->slots[wc->level] < wc->reada_slot) {
8247                 wc->reada_count = wc->reada_count * 2 / 3;
8248                 wc->reada_count = max(wc->reada_count, 2);
8249         } else {
8250                 wc->reada_count = wc->reada_count * 3 / 2;
8251                 wc->reada_count = min_t(int, wc->reada_count,
8252                                         BTRFS_NODEPTRS_PER_BLOCK(root));
8253         }
8254
8255         eb = path->nodes[wc->level];
8256         nritems = btrfs_header_nritems(eb);
8257         blocksize = root->nodesize;
8258
8259         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8260                 if (nread >= wc->reada_count)
8261                         break;
8262
8263                 cond_resched();
8264                 bytenr = btrfs_node_blockptr(eb, slot);
8265                 generation = btrfs_node_ptr_generation(eb, slot);
8266
8267                 if (slot == path->slots[wc->level])
8268                         goto reada;
8269
8270                 if (wc->stage == UPDATE_BACKREF &&
8271                     generation <= root->root_key.offset)
8272                         continue;
8273
8274                 /* We don't lock the tree block, it's OK to be racy here */
8275                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
8276                                                wc->level - 1, 1, &refs,
8277                                                &flags);
8278                 /* We don't care about errors in readahead. */
8279                 if (ret < 0)
8280                         continue;
8281                 BUG_ON(refs == 0);
8282
8283                 if (wc->stage == DROP_REFERENCE) {
8284                         if (refs == 1)
8285                                 goto reada;
8286
8287                         if (wc->level == 1 &&
8288                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8289                                 continue;
8290                         if (!wc->update_ref ||
8291                             generation <= root->root_key.offset)
8292                                 continue;
8293                         btrfs_node_key_to_cpu(eb, &key, slot);
8294                         ret = btrfs_comp_cpu_keys(&key,
8295                                                   &wc->update_progress);
8296                         if (ret < 0)
8297                                 continue;
8298                 } else {
8299                         if (wc->level == 1 &&
8300                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8301                                 continue;
8302                 }
8303 reada:
8304                 readahead_tree_block(root, bytenr);
8305                 nread++;
8306         }
8307         wc->reada_slot = slot;
8308 }
8309
8310 /*
8311  * These may not be seen by the usual inc/dec ref code so we have to
8312  * add them here.
8313  */
8314 static int record_one_subtree_extent(struct btrfs_trans_handle *trans,
8315                                      struct btrfs_root *root, u64 bytenr,
8316                                      u64 num_bytes)
8317 {
8318         struct btrfs_qgroup_extent_record *qrecord;
8319         struct btrfs_delayed_ref_root *delayed_refs;
8320
8321         qrecord = kmalloc(sizeof(*qrecord), GFP_NOFS);
8322         if (!qrecord)
8323                 return -ENOMEM;
8324
8325         qrecord->bytenr = bytenr;
8326         qrecord->num_bytes = num_bytes;
8327         qrecord->old_roots = NULL;
8328
8329         delayed_refs = &trans->transaction->delayed_refs;
8330         spin_lock(&delayed_refs->lock);
8331         if (btrfs_qgroup_insert_dirty_extent(delayed_refs, qrecord))
8332                 kfree(qrecord);
8333         spin_unlock(&delayed_refs->lock);
8334
8335         return 0;
8336 }
8337
8338 static int account_leaf_items(struct btrfs_trans_handle *trans,
8339                               struct btrfs_root *root,
8340                               struct extent_buffer *eb)
8341 {
8342         int nr = btrfs_header_nritems(eb);
8343         int i, extent_type, ret;
8344         struct btrfs_key key;
8345         struct btrfs_file_extent_item *fi;
8346         u64 bytenr, num_bytes;
8347
8348         /* We can be called directly from walk_up_proc() */
8349         if (!root->fs_info->quota_enabled)
8350                 return 0;
8351
8352         for (i = 0; i < nr; i++) {
8353                 btrfs_item_key_to_cpu(eb, &key, i);
8354
8355                 if (key.type != BTRFS_EXTENT_DATA_KEY)
8356                         continue;
8357
8358                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
8359                 /* filter out non qgroup-accountable extents  */
8360                 extent_type = btrfs_file_extent_type(eb, fi);
8361
8362                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
8363                         continue;
8364
8365                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
8366                 if (!bytenr)
8367                         continue;
8368
8369                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
8370
8371                 ret = record_one_subtree_extent(trans, root, bytenr, num_bytes);
8372                 if (ret)
8373                         return ret;
8374         }
8375         return 0;
8376 }
8377
8378 /*
8379  * Walk up the tree from the bottom, freeing leaves and any interior
8380  * nodes which have had all slots visited. If a node (leaf or
8381  * interior) is freed, the node above it will have it's slot
8382  * incremented. The root node will never be freed.
8383  *
8384  * At the end of this function, we should have a path which has all
8385  * slots incremented to the next position for a search. If we need to
8386  * read a new node it will be NULL and the node above it will have the
8387  * correct slot selected for a later read.
8388  *
8389  * If we increment the root nodes slot counter past the number of
8390  * elements, 1 is returned to signal completion of the search.
8391  */
8392 static int adjust_slots_upwards(struct btrfs_root *root,
8393                                 struct btrfs_path *path, int root_level)
8394 {
8395         int level = 0;
8396         int nr, slot;
8397         struct extent_buffer *eb;
8398
8399         if (root_level == 0)
8400                 return 1;
8401
8402         while (level <= root_level) {
8403                 eb = path->nodes[level];
8404                 nr = btrfs_header_nritems(eb);
8405                 path->slots[level]++;
8406                 slot = path->slots[level];
8407                 if (slot >= nr || level == 0) {
8408                         /*
8409                          * Don't free the root -  we will detect this
8410                          * condition after our loop and return a
8411                          * positive value for caller to stop walking the tree.
8412                          */
8413                         if (level != root_level) {
8414                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8415                                 path->locks[level] = 0;
8416
8417                                 free_extent_buffer(eb);
8418                                 path->nodes[level] = NULL;
8419                                 path->slots[level] = 0;
8420                         }
8421                 } else {
8422                         /*
8423                          * We have a valid slot to walk back down
8424                          * from. Stop here so caller can process these
8425                          * new nodes.
8426                          */
8427                         break;
8428                 }
8429
8430                 level++;
8431         }
8432
8433         eb = path->nodes[root_level];
8434         if (path->slots[root_level] >= btrfs_header_nritems(eb))
8435                 return 1;
8436
8437         return 0;
8438 }
8439
8440 /*
8441  * root_eb is the subtree root and is locked before this function is called.
8442  */
8443 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8444                                   struct btrfs_root *root,
8445                                   struct extent_buffer *root_eb,
8446                                   u64 root_gen,
8447                                   int root_level)
8448 {
8449         int ret = 0;
8450         int level;
8451         struct extent_buffer *eb = root_eb;
8452         struct btrfs_path *path = NULL;
8453
8454         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8455         BUG_ON(root_eb == NULL);
8456
8457         if (!root->fs_info->quota_enabled)
8458                 return 0;
8459
8460         if (!extent_buffer_uptodate(root_eb)) {
8461                 ret = btrfs_read_buffer(root_eb, root_gen);
8462                 if (ret)
8463                         goto out;
8464         }
8465
8466         if (root_level == 0) {
8467                 ret = account_leaf_items(trans, root, root_eb);
8468                 goto out;
8469         }
8470
8471         path = btrfs_alloc_path();
8472         if (!path)
8473                 return -ENOMEM;
8474
8475         /*
8476          * Walk down the tree.  Missing extent blocks are filled in as
8477          * we go. Metadata is accounted every time we read a new
8478          * extent block.
8479          *
8480          * When we reach a leaf, we account for file extent items in it,
8481          * walk back up the tree (adjusting slot pointers as we go)
8482          * and restart the search process.
8483          */
8484         extent_buffer_get(root_eb); /* For path */
8485         path->nodes[root_level] = root_eb;
8486         path->slots[root_level] = 0;
8487         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8488 walk_down:
8489         level = root_level;
8490         while (level >= 0) {
8491                 if (path->nodes[level] == NULL) {
8492                         int parent_slot;
8493                         u64 child_gen;
8494                         u64 child_bytenr;
8495
8496                         /* We need to get child blockptr/gen from
8497                          * parent before we can read it. */
8498                         eb = path->nodes[level + 1];
8499                         parent_slot = path->slots[level + 1];
8500                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8501                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8502
8503                         eb = read_tree_block(root, child_bytenr, child_gen);
8504                         if (IS_ERR(eb)) {
8505                                 ret = PTR_ERR(eb);
8506                                 goto out;
8507                         } else if (!extent_buffer_uptodate(eb)) {
8508                                 free_extent_buffer(eb);
8509                                 ret = -EIO;
8510                                 goto out;
8511                         }
8512
8513                         path->nodes[level] = eb;
8514                         path->slots[level] = 0;
8515
8516                         btrfs_tree_read_lock(eb);
8517                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8518                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8519
8520                         ret = record_one_subtree_extent(trans, root, child_bytenr,
8521                                                         root->nodesize);
8522                         if (ret)
8523                                 goto out;
8524                 }
8525
8526                 if (level == 0) {
8527                         ret = account_leaf_items(trans, root, path->nodes[level]);
8528                         if (ret)
8529                                 goto out;
8530
8531                         /* Nonzero return here means we completed our search */
8532                         ret = adjust_slots_upwards(root, path, root_level);
8533                         if (ret)
8534                                 break;
8535
8536                         /* Restart search with new slots */
8537                         goto walk_down;
8538                 }
8539
8540                 level--;
8541         }
8542
8543         ret = 0;
8544 out:
8545         btrfs_free_path(path);
8546
8547         return ret;
8548 }
8549
8550 /*
8551  * helper to process tree block while walking down the tree.
8552  *
8553  * when wc->stage == UPDATE_BACKREF, this function updates
8554  * back refs for pointers in the block.
8555  *
8556  * NOTE: return value 1 means we should stop walking down.
8557  */
8558 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8559                                    struct btrfs_root *root,
8560                                    struct btrfs_path *path,
8561                                    struct walk_control *wc, int lookup_info)
8562 {
8563         int level = wc->level;
8564         struct extent_buffer *eb = path->nodes[level];
8565         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8566         int ret;
8567
8568         if (wc->stage == UPDATE_BACKREF &&
8569             btrfs_header_owner(eb) != root->root_key.objectid)
8570                 return 1;
8571
8572         /*
8573          * when reference count of tree block is 1, it won't increase
8574          * again. once full backref flag is set, we never clear it.
8575          */
8576         if (lookup_info &&
8577             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8578              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8579                 BUG_ON(!path->locks[level]);
8580                 ret = btrfs_lookup_extent_info(trans, root,
8581                                                eb->start, level, 1,
8582                                                &wc->refs[level],
8583                                                &wc->flags[level]);
8584                 BUG_ON(ret == -ENOMEM);
8585                 if (ret)
8586                         return ret;
8587                 BUG_ON(wc->refs[level] == 0);
8588         }
8589
8590         if (wc->stage == DROP_REFERENCE) {
8591                 if (wc->refs[level] > 1)
8592                         return 1;
8593
8594                 if (path->locks[level] && !wc->keep_locks) {
8595                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8596                         path->locks[level] = 0;
8597                 }
8598                 return 0;
8599         }
8600
8601         /* wc->stage == UPDATE_BACKREF */
8602         if (!(wc->flags[level] & flag)) {
8603                 BUG_ON(!path->locks[level]);
8604                 ret = btrfs_inc_ref(trans, root, eb, 1);
8605                 BUG_ON(ret); /* -ENOMEM */
8606                 ret = btrfs_dec_ref(trans, root, eb, 0);
8607                 BUG_ON(ret); /* -ENOMEM */
8608                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8609                                                   eb->len, flag,
8610                                                   btrfs_header_level(eb), 0);
8611                 BUG_ON(ret); /* -ENOMEM */
8612                 wc->flags[level] |= flag;
8613         }
8614
8615         /*
8616          * the block is shared by multiple trees, so it's not good to
8617          * keep the tree lock
8618          */
8619         if (path->locks[level] && level > 0) {
8620                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8621                 path->locks[level] = 0;
8622         }
8623         return 0;
8624 }
8625
8626 /*
8627  * helper to process tree block pointer.
8628  *
8629  * when wc->stage == DROP_REFERENCE, this function checks
8630  * reference count of the block pointed to. if the block
8631  * is shared and we need update back refs for the subtree
8632  * rooted at the block, this function changes wc->stage to
8633  * UPDATE_BACKREF. if the block is shared and there is no
8634  * need to update back, this function drops the reference
8635  * to the block.
8636  *
8637  * NOTE: return value 1 means we should stop walking down.
8638  */
8639 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8640                                  struct btrfs_root *root,
8641                                  struct btrfs_path *path,
8642                                  struct walk_control *wc, int *lookup_info)
8643 {
8644         u64 bytenr;
8645         u64 generation;
8646         u64 parent;
8647         u32 blocksize;
8648         struct btrfs_key key;
8649         struct extent_buffer *next;
8650         int level = wc->level;
8651         int reada = 0;
8652         int ret = 0;
8653         bool need_account = false;
8654
8655         generation = btrfs_node_ptr_generation(path->nodes[level],
8656                                                path->slots[level]);
8657         /*
8658          * if the lower level block was created before the snapshot
8659          * was created, we know there is no need to update back refs
8660          * for the subtree
8661          */
8662         if (wc->stage == UPDATE_BACKREF &&
8663             generation <= root->root_key.offset) {
8664                 *lookup_info = 1;
8665                 return 1;
8666         }
8667
8668         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8669         blocksize = root->nodesize;
8670
8671         next = btrfs_find_tree_block(root->fs_info, bytenr);
8672         if (!next) {
8673                 next = btrfs_find_create_tree_block(root, bytenr);
8674                 if (IS_ERR(next))
8675                         return PTR_ERR(next);
8676
8677                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8678                                                level - 1);
8679                 reada = 1;
8680         }
8681         btrfs_tree_lock(next);
8682         btrfs_set_lock_blocking(next);
8683
8684         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8685                                        &wc->refs[level - 1],
8686                                        &wc->flags[level - 1]);
8687         if (ret < 0) {
8688                 btrfs_tree_unlock(next);
8689                 return ret;
8690         }
8691
8692         if (unlikely(wc->refs[level - 1] == 0)) {
8693                 btrfs_err(root->fs_info, "Missing references.");
8694                 BUG();
8695         }
8696         *lookup_info = 0;
8697
8698         if (wc->stage == DROP_REFERENCE) {
8699                 if (wc->refs[level - 1] > 1) {
8700                         need_account = true;
8701                         if (level == 1 &&
8702                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8703                                 goto skip;
8704
8705                         if (!wc->update_ref ||
8706                             generation <= root->root_key.offset)
8707                                 goto skip;
8708
8709                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8710                                               path->slots[level]);
8711                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8712                         if (ret < 0)
8713                                 goto skip;
8714
8715                         wc->stage = UPDATE_BACKREF;
8716                         wc->shared_level = level - 1;
8717                 }
8718         } else {
8719                 if (level == 1 &&
8720                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8721                         goto skip;
8722         }
8723
8724         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8725                 btrfs_tree_unlock(next);
8726                 free_extent_buffer(next);
8727                 next = NULL;
8728                 *lookup_info = 1;
8729         }
8730
8731         if (!next) {
8732                 if (reada && level == 1)
8733                         reada_walk_down(trans, root, wc, path);
8734                 next = read_tree_block(root, bytenr, generation);
8735                 if (IS_ERR(next)) {
8736                         return PTR_ERR(next);
8737                 } else if (!extent_buffer_uptodate(next)) {
8738                         free_extent_buffer(next);
8739                         return -EIO;
8740                 }
8741                 btrfs_tree_lock(next);
8742                 btrfs_set_lock_blocking(next);
8743         }
8744
8745         level--;
8746         BUG_ON(level != btrfs_header_level(next));
8747         path->nodes[level] = next;
8748         path->slots[level] = 0;
8749         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8750         wc->level = level;
8751         if (wc->level == 1)
8752                 wc->reada_slot = 0;
8753         return 0;
8754 skip:
8755         wc->refs[level - 1] = 0;
8756         wc->flags[level - 1] = 0;
8757         if (wc->stage == DROP_REFERENCE) {
8758                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8759                         parent = path->nodes[level]->start;
8760                 } else {
8761                         BUG_ON(root->root_key.objectid !=
8762                                btrfs_header_owner(path->nodes[level]));
8763                         parent = 0;
8764                 }
8765
8766                 if (need_account) {
8767                         ret = account_shared_subtree(trans, root, next,
8768                                                      generation, level - 1);
8769                         if (ret) {
8770                                 btrfs_err_rl(root->fs_info,
8771                                         "Error "
8772                                         "%d accounting shared subtree. Quota "
8773                                         "is out of sync, rescan required.",
8774                                         ret);
8775                         }
8776                 }
8777                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8778                                 root->root_key.objectid, level - 1, 0);
8779                 BUG_ON(ret); /* -ENOMEM */
8780         }
8781         btrfs_tree_unlock(next);
8782         free_extent_buffer(next);
8783         *lookup_info = 1;
8784         return 1;
8785 }
8786
8787 /*
8788  * helper to process tree block while walking up the tree.
8789  *
8790  * when wc->stage == DROP_REFERENCE, this function drops
8791  * reference count on the block.
8792  *
8793  * when wc->stage == UPDATE_BACKREF, this function changes
8794  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8795  * to UPDATE_BACKREF previously while processing the block.
8796  *
8797  * NOTE: return value 1 means we should stop walking up.
8798  */
8799 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8800                                  struct btrfs_root *root,
8801                                  struct btrfs_path *path,
8802                                  struct walk_control *wc)
8803 {
8804         int ret;
8805         int level = wc->level;
8806         struct extent_buffer *eb = path->nodes[level];
8807         u64 parent = 0;
8808
8809         if (wc->stage == UPDATE_BACKREF) {
8810                 BUG_ON(wc->shared_level < level);
8811                 if (level < wc->shared_level)
8812                         goto out;
8813
8814                 ret = find_next_key(path, level + 1, &wc->update_progress);
8815                 if (ret > 0)
8816                         wc->update_ref = 0;
8817
8818                 wc->stage = DROP_REFERENCE;
8819                 wc->shared_level = -1;
8820                 path->slots[level] = 0;
8821
8822                 /*
8823                  * check reference count again if the block isn't locked.
8824                  * we should start walking down the tree again if reference
8825                  * count is one.
8826                  */
8827                 if (!path->locks[level]) {
8828                         BUG_ON(level == 0);
8829                         btrfs_tree_lock(eb);
8830                         btrfs_set_lock_blocking(eb);
8831                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8832
8833                         ret = btrfs_lookup_extent_info(trans, root,
8834                                                        eb->start, level, 1,
8835                                                        &wc->refs[level],
8836                                                        &wc->flags[level]);
8837                         if (ret < 0) {
8838                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8839                                 path->locks[level] = 0;
8840                                 return ret;
8841                         }
8842                         BUG_ON(wc->refs[level] == 0);
8843                         if (wc->refs[level] == 1) {
8844                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8845                                 path->locks[level] = 0;
8846                                 return 1;
8847                         }
8848                 }
8849         }
8850
8851         /* wc->stage == DROP_REFERENCE */
8852         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8853
8854         if (wc->refs[level] == 1) {
8855                 if (level == 0) {
8856                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8857                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8858                         else
8859                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8860                         BUG_ON(ret); /* -ENOMEM */
8861                         ret = account_leaf_items(trans, root, eb);
8862                         if (ret) {
8863                                 btrfs_err_rl(root->fs_info,
8864                                         "error "
8865                                         "%d accounting leaf items. Quota "
8866                                         "is out of sync, rescan required.",
8867                                         ret);
8868                         }
8869                 }
8870                 /* make block locked assertion in clean_tree_block happy */
8871                 if (!path->locks[level] &&
8872                     btrfs_header_generation(eb) == trans->transid) {
8873                         btrfs_tree_lock(eb);
8874                         btrfs_set_lock_blocking(eb);
8875                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8876                 }
8877                 clean_tree_block(trans, root->fs_info, eb);
8878         }
8879
8880         if (eb == root->node) {
8881                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8882                         parent = eb->start;
8883                 else
8884                         BUG_ON(root->root_key.objectid !=
8885                                btrfs_header_owner(eb));
8886         } else {
8887                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8888                         parent = path->nodes[level + 1]->start;
8889                 else
8890                         BUG_ON(root->root_key.objectid !=
8891                                btrfs_header_owner(path->nodes[level + 1]));
8892         }
8893
8894         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8895 out:
8896         wc->refs[level] = 0;
8897         wc->flags[level] = 0;
8898         return 0;
8899 }
8900
8901 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8902                                    struct btrfs_root *root,
8903                                    struct btrfs_path *path,
8904                                    struct walk_control *wc)
8905 {
8906         int level = wc->level;
8907         int lookup_info = 1;
8908         int ret;
8909
8910         while (level >= 0) {
8911                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8912                 if (ret > 0)
8913                         break;
8914
8915                 if (level == 0)
8916                         break;
8917
8918                 if (path->slots[level] >=
8919                     btrfs_header_nritems(path->nodes[level]))
8920                         break;
8921
8922                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8923                 if (ret > 0) {
8924                         path->slots[level]++;
8925                         continue;
8926                 } else if (ret < 0)
8927                         return ret;
8928                 level = wc->level;
8929         }
8930         return 0;
8931 }
8932
8933 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8934                                  struct btrfs_root *root,
8935                                  struct btrfs_path *path,
8936                                  struct walk_control *wc, int max_level)
8937 {
8938         int level = wc->level;
8939         int ret;
8940
8941         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8942         while (level < max_level && path->nodes[level]) {
8943                 wc->level = level;
8944                 if (path->slots[level] + 1 <
8945                     btrfs_header_nritems(path->nodes[level])) {
8946                         path->slots[level]++;
8947                         return 0;
8948                 } else {
8949                         ret = walk_up_proc(trans, root, path, wc);
8950                         if (ret > 0)
8951                                 return 0;
8952
8953                         if (path->locks[level]) {
8954                                 btrfs_tree_unlock_rw(path->nodes[level],
8955                                                      path->locks[level]);
8956                                 path->locks[level] = 0;
8957                         }
8958                         free_extent_buffer(path->nodes[level]);
8959                         path->nodes[level] = NULL;
8960                         level++;
8961                 }
8962         }
8963         return 1;
8964 }
8965
8966 /*
8967  * drop a subvolume tree.
8968  *
8969  * this function traverses the tree freeing any blocks that only
8970  * referenced by the tree.
8971  *
8972  * when a shared tree block is found. this function decreases its
8973  * reference count by one. if update_ref is true, this function
8974  * also make sure backrefs for the shared block and all lower level
8975  * blocks are properly updated.
8976  *
8977  * If called with for_reloc == 0, may exit early with -EAGAIN
8978  */
8979 int btrfs_drop_snapshot(struct btrfs_root *root,
8980                          struct btrfs_block_rsv *block_rsv, int update_ref,
8981                          int for_reloc)
8982 {
8983         struct btrfs_path *path;
8984         struct btrfs_trans_handle *trans;
8985         struct btrfs_root *tree_root = root->fs_info->tree_root;
8986         struct btrfs_root_item *root_item = &root->root_item;
8987         struct walk_control *wc;
8988         struct btrfs_key key;
8989         int err = 0;
8990         int ret;
8991         int level;
8992         bool root_dropped = false;
8993
8994         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
8995
8996         path = btrfs_alloc_path();
8997         if (!path) {
8998                 err = -ENOMEM;
8999                 goto out;
9000         }
9001
9002         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9003         if (!wc) {
9004                 btrfs_free_path(path);
9005                 err = -ENOMEM;
9006                 goto out;
9007         }
9008
9009         trans = btrfs_start_transaction(tree_root, 0);
9010         if (IS_ERR(trans)) {
9011                 err = PTR_ERR(trans);
9012                 goto out_free;
9013         }
9014
9015         if (block_rsv)
9016                 trans->block_rsv = block_rsv;
9017
9018         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9019                 level = btrfs_header_level(root->node);
9020                 path->nodes[level] = btrfs_lock_root_node(root);
9021                 btrfs_set_lock_blocking(path->nodes[level]);
9022                 path->slots[level] = 0;
9023                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9024                 memset(&wc->update_progress, 0,
9025                        sizeof(wc->update_progress));
9026         } else {
9027                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9028                 memcpy(&wc->update_progress, &key,
9029                        sizeof(wc->update_progress));
9030
9031                 level = root_item->drop_level;
9032                 BUG_ON(level == 0);
9033                 path->lowest_level = level;
9034                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9035                 path->lowest_level = 0;
9036                 if (ret < 0) {
9037                         err = ret;
9038                         goto out_end_trans;
9039                 }
9040                 WARN_ON(ret > 0);
9041
9042                 /*
9043                  * unlock our path, this is safe because only this
9044                  * function is allowed to delete this snapshot
9045                  */
9046                 btrfs_unlock_up_safe(path, 0);
9047
9048                 level = btrfs_header_level(root->node);
9049                 while (1) {
9050                         btrfs_tree_lock(path->nodes[level]);
9051                         btrfs_set_lock_blocking(path->nodes[level]);
9052                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9053
9054                         ret = btrfs_lookup_extent_info(trans, root,
9055                                                 path->nodes[level]->start,
9056                                                 level, 1, &wc->refs[level],
9057                                                 &wc->flags[level]);
9058                         if (ret < 0) {
9059                                 err = ret;
9060                                 goto out_end_trans;
9061                         }
9062                         BUG_ON(wc->refs[level] == 0);
9063
9064                         if (level == root_item->drop_level)
9065                                 break;
9066
9067                         btrfs_tree_unlock(path->nodes[level]);
9068                         path->locks[level] = 0;
9069                         WARN_ON(wc->refs[level] != 1);
9070                         level--;
9071                 }
9072         }
9073
9074         wc->level = level;
9075         wc->shared_level = -1;
9076         wc->stage = DROP_REFERENCE;
9077         wc->update_ref = update_ref;
9078         wc->keep_locks = 0;
9079         wc->for_reloc = for_reloc;
9080         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9081
9082         while (1) {
9083
9084                 ret = walk_down_tree(trans, root, path, wc);
9085                 if (ret < 0) {
9086                         err = ret;
9087                         break;
9088                 }
9089
9090                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9091                 if (ret < 0) {
9092                         err = ret;
9093                         break;
9094                 }
9095
9096                 if (ret > 0) {
9097                         BUG_ON(wc->stage != DROP_REFERENCE);
9098                         break;
9099                 }
9100
9101                 if (wc->stage == DROP_REFERENCE) {
9102                         level = wc->level;
9103                         btrfs_node_key(path->nodes[level],
9104                                        &root_item->drop_progress,
9105                                        path->slots[level]);
9106                         root_item->drop_level = level;
9107                 }
9108
9109                 BUG_ON(wc->level == 0);
9110                 if (btrfs_should_end_transaction(trans, tree_root) ||
9111                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
9112                         ret = btrfs_update_root(trans, tree_root,
9113                                                 &root->root_key,
9114                                                 root_item);
9115                         if (ret) {
9116                                 btrfs_abort_transaction(trans, tree_root, ret);
9117                                 err = ret;
9118                                 goto out_end_trans;
9119                         }
9120
9121                         btrfs_end_transaction_throttle(trans, tree_root);
9122                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
9123                                 pr_debug("BTRFS: drop snapshot early exit\n");
9124                                 err = -EAGAIN;
9125                                 goto out_free;
9126                         }
9127
9128                         trans = btrfs_start_transaction(tree_root, 0);
9129                         if (IS_ERR(trans)) {
9130                                 err = PTR_ERR(trans);
9131                                 goto out_free;
9132                         }
9133                         if (block_rsv)
9134                                 trans->block_rsv = block_rsv;
9135                 }
9136         }
9137         btrfs_release_path(path);
9138         if (err)
9139                 goto out_end_trans;
9140
9141         ret = btrfs_del_root(trans, tree_root, &root->root_key);
9142         if (ret) {
9143                 btrfs_abort_transaction(trans, tree_root, ret);
9144                 goto out_end_trans;
9145         }
9146
9147         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9148                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9149                                       NULL, NULL);
9150                 if (ret < 0) {
9151                         btrfs_abort_transaction(trans, tree_root, ret);
9152                         err = ret;
9153                         goto out_end_trans;
9154                 } else if (ret > 0) {
9155                         /* if we fail to delete the orphan item this time
9156                          * around, it'll get picked up the next time.
9157                          *
9158                          * The most common failure here is just -ENOENT.
9159                          */
9160                         btrfs_del_orphan_item(trans, tree_root,
9161                                               root->root_key.objectid);
9162                 }
9163         }
9164
9165         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9166                 btrfs_add_dropped_root(trans, root);
9167         } else {
9168                 free_extent_buffer(root->node);
9169                 free_extent_buffer(root->commit_root);
9170                 btrfs_put_fs_root(root);
9171         }
9172         root_dropped = true;
9173 out_end_trans:
9174         btrfs_end_transaction_throttle(trans, tree_root);
9175 out_free:
9176         kfree(wc);
9177         btrfs_free_path(path);
9178 out:
9179         /*
9180          * So if we need to stop dropping the snapshot for whatever reason we
9181          * need to make sure to add it back to the dead root list so that we
9182          * keep trying to do the work later.  This also cleans up roots if we
9183          * don't have it in the radix (like when we recover after a power fail
9184          * or unmount) so we don't leak memory.
9185          */
9186         if (!for_reloc && root_dropped == false)
9187                 btrfs_add_dead_root(root);
9188         if (err && err != -EAGAIN)
9189                 btrfs_handle_fs_error(root->fs_info, err, NULL);
9190         return err;
9191 }
9192
9193 /*
9194  * drop subtree rooted at tree block 'node'.
9195  *
9196  * NOTE: this function will unlock and release tree block 'node'
9197  * only used by relocation code
9198  */
9199 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9200                         struct btrfs_root *root,
9201                         struct extent_buffer *node,
9202                         struct extent_buffer *parent)
9203 {
9204         struct btrfs_path *path;
9205         struct walk_control *wc;
9206         int level;
9207         int parent_level;
9208         int ret = 0;
9209         int wret;
9210
9211         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9212
9213         path = btrfs_alloc_path();
9214         if (!path)
9215                 return -ENOMEM;
9216
9217         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9218         if (!wc) {
9219                 btrfs_free_path(path);
9220                 return -ENOMEM;
9221         }
9222
9223         btrfs_assert_tree_locked(parent);
9224         parent_level = btrfs_header_level(parent);
9225         extent_buffer_get(parent);
9226         path->nodes[parent_level] = parent;
9227         path->slots[parent_level] = btrfs_header_nritems(parent);
9228
9229         btrfs_assert_tree_locked(node);
9230         level = btrfs_header_level(node);
9231         path->nodes[level] = node;
9232         path->slots[level] = 0;
9233         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9234
9235         wc->refs[parent_level] = 1;
9236         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9237         wc->level = level;
9238         wc->shared_level = -1;
9239         wc->stage = DROP_REFERENCE;
9240         wc->update_ref = 0;
9241         wc->keep_locks = 1;
9242         wc->for_reloc = 1;
9243         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
9244
9245         while (1) {
9246                 wret = walk_down_tree(trans, root, path, wc);
9247                 if (wret < 0) {
9248                         ret = wret;
9249                         break;
9250                 }
9251
9252                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9253                 if (wret < 0)
9254                         ret = wret;
9255                 if (wret != 0)
9256                         break;
9257         }
9258
9259         kfree(wc);
9260         btrfs_free_path(path);
9261         return ret;
9262 }
9263
9264 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
9265 {
9266         u64 num_devices;
9267         u64 stripped;
9268
9269         /*
9270          * if restripe for this chunk_type is on pick target profile and
9271          * return, otherwise do the usual balance
9272          */
9273         stripped = get_restripe_target(root->fs_info, flags);
9274         if (stripped)
9275                 return extended_to_chunk(stripped);
9276
9277         num_devices = root->fs_info->fs_devices->rw_devices;
9278
9279         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9280                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9281                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9282
9283         if (num_devices == 1) {
9284                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9285                 stripped = flags & ~stripped;
9286
9287                 /* turn raid0 into single device chunks */
9288                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9289                         return stripped;
9290
9291                 /* turn mirroring into duplication */
9292                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9293                              BTRFS_BLOCK_GROUP_RAID10))
9294                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9295         } else {
9296                 /* they already had raid on here, just return */
9297                 if (flags & stripped)
9298                         return flags;
9299
9300                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9301                 stripped = flags & ~stripped;
9302
9303                 /* switch duplicated blocks with raid1 */
9304                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9305                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9306
9307                 /* this is drive concat, leave it alone */
9308         }
9309
9310         return flags;
9311 }
9312
9313 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9314 {
9315         struct btrfs_space_info *sinfo = cache->space_info;
9316         u64 num_bytes;
9317         u64 min_allocable_bytes;
9318         int ret = -ENOSPC;
9319
9320         /*
9321          * We need some metadata space and system metadata space for
9322          * allocating chunks in some corner cases until we force to set
9323          * it to be readonly.
9324          */
9325         if ((sinfo->flags &
9326              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9327             !force)
9328                 min_allocable_bytes = SZ_1M;
9329         else
9330                 min_allocable_bytes = 0;
9331
9332         spin_lock(&sinfo->lock);
9333         spin_lock(&cache->lock);
9334
9335         if (cache->ro) {
9336                 cache->ro++;
9337                 ret = 0;
9338                 goto out;
9339         }
9340
9341         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9342                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9343
9344         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
9345             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
9346             min_allocable_bytes <= sinfo->total_bytes) {
9347                 sinfo->bytes_readonly += num_bytes;
9348                 cache->ro++;
9349                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9350                 ret = 0;
9351         }
9352 out:
9353         spin_unlock(&cache->lock);
9354         spin_unlock(&sinfo->lock);
9355         return ret;
9356 }
9357
9358 int btrfs_inc_block_group_ro(struct btrfs_root *root,
9359                              struct btrfs_block_group_cache *cache)
9360
9361 {
9362         struct btrfs_trans_handle *trans;
9363         u64 alloc_flags;
9364         int ret;
9365
9366 again:
9367         trans = btrfs_join_transaction(root);
9368         if (IS_ERR(trans))
9369                 return PTR_ERR(trans);
9370
9371         /*
9372          * we're not allowed to set block groups readonly after the dirty
9373          * block groups cache has started writing.  If it already started,
9374          * back off and let this transaction commit
9375          */
9376         mutex_lock(&root->fs_info->ro_block_group_mutex);
9377         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9378                 u64 transid = trans->transid;
9379
9380                 mutex_unlock(&root->fs_info->ro_block_group_mutex);
9381                 btrfs_end_transaction(trans, root);
9382
9383                 ret = btrfs_wait_for_commit(root, transid);
9384                 if (ret)
9385                         return ret;
9386                 goto again;
9387         }
9388
9389         /*
9390          * if we are changing raid levels, try to allocate a corresponding
9391          * block group with the new raid level.
9392          */
9393         alloc_flags = update_block_group_flags(root, cache->flags);
9394         if (alloc_flags != cache->flags) {
9395                 ret = do_chunk_alloc(trans, root, alloc_flags,
9396                                      CHUNK_ALLOC_FORCE);
9397                 /*
9398                  * ENOSPC is allowed here, we may have enough space
9399                  * already allocated at the new raid level to
9400                  * carry on
9401                  */
9402                 if (ret == -ENOSPC)
9403                         ret = 0;
9404                 if (ret < 0)
9405                         goto out;
9406         }
9407
9408         ret = inc_block_group_ro(cache, 0);
9409         if (!ret)
9410                 goto out;
9411         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
9412         ret = do_chunk_alloc(trans, root, alloc_flags,
9413                              CHUNK_ALLOC_FORCE);
9414         if (ret < 0)
9415                 goto out;
9416         ret = inc_block_group_ro(cache, 0);
9417 out:
9418         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9419                 alloc_flags = update_block_group_flags(root, cache->flags);
9420                 lock_chunks(root->fs_info->chunk_root);
9421                 check_system_chunk(trans, root, alloc_flags);
9422                 unlock_chunks(root->fs_info->chunk_root);
9423         }
9424         mutex_unlock(&root->fs_info->ro_block_group_mutex);
9425
9426         btrfs_end_transaction(trans, root);
9427         return ret;
9428 }
9429
9430 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9431                             struct btrfs_root *root, u64 type)
9432 {
9433         u64 alloc_flags = get_alloc_profile(root, type);
9434         return do_chunk_alloc(trans, root, alloc_flags,
9435                               CHUNK_ALLOC_FORCE);
9436 }
9437
9438 /*
9439  * helper to account the unused space of all the readonly block group in the
9440  * space_info. takes mirrors into account.
9441  */
9442 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9443 {
9444         struct btrfs_block_group_cache *block_group;
9445         u64 free_bytes = 0;
9446         int factor;
9447
9448         /* It's df, we don't care if it's racy */
9449         if (list_empty(&sinfo->ro_bgs))
9450                 return 0;
9451
9452         spin_lock(&sinfo->lock);
9453         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9454                 spin_lock(&block_group->lock);
9455
9456                 if (!block_group->ro) {
9457                         spin_unlock(&block_group->lock);
9458                         continue;
9459                 }
9460
9461                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9462                                           BTRFS_BLOCK_GROUP_RAID10 |
9463                                           BTRFS_BLOCK_GROUP_DUP))
9464                         factor = 2;
9465                 else
9466                         factor = 1;
9467
9468                 free_bytes += (block_group->key.offset -
9469                                btrfs_block_group_used(&block_group->item)) *
9470                                factor;
9471
9472                 spin_unlock(&block_group->lock);
9473         }
9474         spin_unlock(&sinfo->lock);
9475
9476         return free_bytes;
9477 }
9478
9479 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9480                               struct btrfs_block_group_cache *cache)
9481 {
9482         struct btrfs_space_info *sinfo = cache->space_info;
9483         u64 num_bytes;
9484
9485         BUG_ON(!cache->ro);
9486
9487         spin_lock(&sinfo->lock);
9488         spin_lock(&cache->lock);
9489         if (!--cache->ro) {
9490                 num_bytes = cache->key.offset - cache->reserved -
9491                             cache->pinned - cache->bytes_super -
9492                             btrfs_block_group_used(&cache->item);
9493                 sinfo->bytes_readonly -= num_bytes;
9494                 list_del_init(&cache->ro_list);
9495         }
9496         spin_unlock(&cache->lock);
9497         spin_unlock(&sinfo->lock);
9498 }
9499
9500 /*
9501  * checks to see if its even possible to relocate this block group.
9502  *
9503  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9504  * ok to go ahead and try.
9505  */
9506 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9507 {
9508         struct btrfs_block_group_cache *block_group;
9509         struct btrfs_space_info *space_info;
9510         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9511         struct btrfs_device *device;
9512         struct btrfs_trans_handle *trans;
9513         u64 min_free;
9514         u64 dev_min = 1;
9515         u64 dev_nr = 0;
9516         u64 target;
9517         int debug;
9518         int index;
9519         int full = 0;
9520         int ret = 0;
9521
9522         debug = btrfs_test_opt(root, ENOSPC_DEBUG);
9523
9524         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9525
9526         /* odd, couldn't find the block group, leave it alone */
9527         if (!block_group) {
9528                 if (debug)
9529                         btrfs_warn(root->fs_info,
9530                                    "can't find block group for bytenr %llu",
9531                                    bytenr);
9532                 return -1;
9533         }
9534
9535         min_free = btrfs_block_group_used(&block_group->item);
9536
9537         /* no bytes used, we're good */
9538         if (!min_free)
9539                 goto out;
9540
9541         space_info = block_group->space_info;
9542         spin_lock(&space_info->lock);
9543
9544         full = space_info->full;
9545
9546         /*
9547          * if this is the last block group we have in this space, we can't
9548          * relocate it unless we're able to allocate a new chunk below.
9549          *
9550          * Otherwise, we need to make sure we have room in the space to handle
9551          * all of the extents from this block group.  If we can, we're good
9552          */
9553         if ((space_info->total_bytes != block_group->key.offset) &&
9554             (space_info->bytes_used + space_info->bytes_reserved +
9555              space_info->bytes_pinned + space_info->bytes_readonly +
9556              min_free < space_info->total_bytes)) {
9557                 spin_unlock(&space_info->lock);
9558                 goto out;
9559         }
9560         spin_unlock(&space_info->lock);
9561
9562         /*
9563          * ok we don't have enough space, but maybe we have free space on our
9564          * devices to allocate new chunks for relocation, so loop through our
9565          * alloc devices and guess if we have enough space.  if this block
9566          * group is going to be restriped, run checks against the target
9567          * profile instead of the current one.
9568          */
9569         ret = -1;
9570
9571         /*
9572          * index:
9573          *      0: raid10
9574          *      1: raid1
9575          *      2: dup
9576          *      3: raid0
9577          *      4: single
9578          */
9579         target = get_restripe_target(root->fs_info, block_group->flags);
9580         if (target) {
9581                 index = __get_raid_index(extended_to_chunk(target));
9582         } else {
9583                 /*
9584                  * this is just a balance, so if we were marked as full
9585                  * we know there is no space for a new chunk
9586                  */
9587                 if (full) {
9588                         if (debug)
9589                                 btrfs_warn(root->fs_info,
9590                                         "no space to alloc new chunk for block group %llu",
9591                                         block_group->key.objectid);
9592                         goto out;
9593                 }
9594
9595                 index = get_block_group_index(block_group);
9596         }
9597
9598         if (index == BTRFS_RAID_RAID10) {
9599                 dev_min = 4;
9600                 /* Divide by 2 */
9601                 min_free >>= 1;
9602         } else if (index == BTRFS_RAID_RAID1) {
9603                 dev_min = 2;
9604         } else if (index == BTRFS_RAID_DUP) {
9605                 /* Multiply by 2 */
9606                 min_free <<= 1;
9607         } else if (index == BTRFS_RAID_RAID0) {
9608                 dev_min = fs_devices->rw_devices;
9609                 min_free = div64_u64(min_free, dev_min);
9610         }
9611
9612         /* We need to do this so that we can look at pending chunks */
9613         trans = btrfs_join_transaction(root);
9614         if (IS_ERR(trans)) {
9615                 ret = PTR_ERR(trans);
9616                 goto out;
9617         }
9618
9619         mutex_lock(&root->fs_info->chunk_mutex);
9620         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9621                 u64 dev_offset;
9622
9623                 /*
9624                  * check to make sure we can actually find a chunk with enough
9625                  * space to fit our block group in.
9626                  */
9627                 if (device->total_bytes > device->bytes_used + min_free &&
9628                     !device->is_tgtdev_for_dev_replace) {
9629                         ret = find_free_dev_extent(trans, device, min_free,
9630                                                    &dev_offset, NULL);
9631                         if (!ret)
9632                                 dev_nr++;
9633
9634                         if (dev_nr >= dev_min)
9635                                 break;
9636
9637                         ret = -1;
9638                 }
9639         }
9640         if (debug && ret == -1)
9641                 btrfs_warn(root->fs_info,
9642                         "no space to allocate a new chunk for block group %llu",
9643                         block_group->key.objectid);
9644         mutex_unlock(&root->fs_info->chunk_mutex);
9645         btrfs_end_transaction(trans, root);
9646 out:
9647         btrfs_put_block_group(block_group);
9648         return ret;
9649 }
9650
9651 static int find_first_block_group(struct btrfs_root *root,
9652                 struct btrfs_path *path, struct btrfs_key *key)
9653 {
9654         int ret = 0;
9655         struct btrfs_key found_key;
9656         struct extent_buffer *leaf;
9657         int slot;
9658
9659         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9660         if (ret < 0)
9661                 goto out;
9662
9663         while (1) {
9664                 slot = path->slots[0];
9665                 leaf = path->nodes[0];
9666                 if (slot >= btrfs_header_nritems(leaf)) {
9667                         ret = btrfs_next_leaf(root, path);
9668                         if (ret == 0)
9669                                 continue;
9670                         if (ret < 0)
9671                                 goto out;
9672                         break;
9673                 }
9674                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9675
9676                 if (found_key.objectid >= key->objectid &&
9677                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9678                         ret = 0;
9679                         goto out;
9680                 }
9681                 path->slots[0]++;
9682         }
9683 out:
9684         return ret;
9685 }
9686
9687 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9688 {
9689         struct btrfs_block_group_cache *block_group;
9690         u64 last = 0;
9691
9692         while (1) {
9693                 struct inode *inode;
9694
9695                 block_group = btrfs_lookup_first_block_group(info, last);
9696                 while (block_group) {
9697                         spin_lock(&block_group->lock);
9698                         if (block_group->iref)
9699                                 break;
9700                         spin_unlock(&block_group->lock);
9701                         block_group = next_block_group(info->tree_root,
9702                                                        block_group);
9703                 }
9704                 if (!block_group) {
9705                         if (last == 0)
9706                                 break;
9707                         last = 0;
9708                         continue;
9709                 }
9710
9711                 inode = block_group->inode;
9712                 block_group->iref = 0;
9713                 block_group->inode = NULL;
9714                 spin_unlock(&block_group->lock);
9715                 iput(inode);
9716                 last = block_group->key.objectid + block_group->key.offset;
9717                 btrfs_put_block_group(block_group);
9718         }
9719 }
9720
9721 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9722 {
9723         struct btrfs_block_group_cache *block_group;
9724         struct btrfs_space_info *space_info;
9725         struct btrfs_caching_control *caching_ctl;
9726         struct rb_node *n;
9727
9728         down_write(&info->commit_root_sem);
9729         while (!list_empty(&info->caching_block_groups)) {
9730                 caching_ctl = list_entry(info->caching_block_groups.next,
9731                                          struct btrfs_caching_control, list);
9732                 list_del(&caching_ctl->list);
9733                 put_caching_control(caching_ctl);
9734         }
9735         up_write(&info->commit_root_sem);
9736
9737         spin_lock(&info->unused_bgs_lock);
9738         while (!list_empty(&info->unused_bgs)) {
9739                 block_group = list_first_entry(&info->unused_bgs,
9740                                                struct btrfs_block_group_cache,
9741                                                bg_list);
9742                 list_del_init(&block_group->bg_list);
9743                 btrfs_put_block_group(block_group);
9744         }
9745         spin_unlock(&info->unused_bgs_lock);
9746
9747         spin_lock(&info->block_group_cache_lock);
9748         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9749                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9750                                        cache_node);
9751                 rb_erase(&block_group->cache_node,
9752                          &info->block_group_cache_tree);
9753                 RB_CLEAR_NODE(&block_group->cache_node);
9754                 spin_unlock(&info->block_group_cache_lock);
9755
9756                 down_write(&block_group->space_info->groups_sem);
9757                 list_del(&block_group->list);
9758                 up_write(&block_group->space_info->groups_sem);
9759
9760                 if (block_group->cached == BTRFS_CACHE_STARTED)
9761                         wait_block_group_cache_done(block_group);
9762
9763                 /*
9764                  * We haven't cached this block group, which means we could
9765                  * possibly have excluded extents on this block group.
9766                  */
9767                 if (block_group->cached == BTRFS_CACHE_NO ||
9768                     block_group->cached == BTRFS_CACHE_ERROR)
9769                         free_excluded_extents(info->extent_root, block_group);
9770
9771                 btrfs_remove_free_space_cache(block_group);
9772                 btrfs_put_block_group(block_group);
9773
9774                 spin_lock(&info->block_group_cache_lock);
9775         }
9776         spin_unlock(&info->block_group_cache_lock);
9777
9778         /* now that all the block groups are freed, go through and
9779          * free all the space_info structs.  This is only called during
9780          * the final stages of unmount, and so we know nobody is
9781          * using them.  We call synchronize_rcu() once before we start,
9782          * just to be on the safe side.
9783          */
9784         synchronize_rcu();
9785
9786         release_global_block_rsv(info);
9787
9788         while (!list_empty(&info->space_info)) {
9789                 int i;
9790
9791                 space_info = list_entry(info->space_info.next,
9792                                         struct btrfs_space_info,
9793                                         list);
9794                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
9795                         if (WARN_ON(space_info->bytes_pinned > 0 ||
9796                             space_info->bytes_reserved > 0 ||
9797                             space_info->bytes_may_use > 0)) {
9798                                 dump_space_info(space_info, 0, 0);
9799                         }
9800                 }
9801                 list_del(&space_info->list);
9802                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9803                         struct kobject *kobj;
9804                         kobj = space_info->block_group_kobjs[i];
9805                         space_info->block_group_kobjs[i] = NULL;
9806                         if (kobj) {
9807                                 kobject_del(kobj);
9808                                 kobject_put(kobj);
9809                         }
9810                 }
9811                 kobject_del(&space_info->kobj);
9812                 kobject_put(&space_info->kobj);
9813         }
9814         return 0;
9815 }
9816
9817 static void __link_block_group(struct btrfs_space_info *space_info,
9818                                struct btrfs_block_group_cache *cache)
9819 {
9820         int index = get_block_group_index(cache);
9821         bool first = false;
9822
9823         down_write(&space_info->groups_sem);
9824         if (list_empty(&space_info->block_groups[index]))
9825                 first = true;
9826         list_add_tail(&cache->list, &space_info->block_groups[index]);
9827         up_write(&space_info->groups_sem);
9828
9829         if (first) {
9830                 struct raid_kobject *rkobj;
9831                 int ret;
9832
9833                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9834                 if (!rkobj)
9835                         goto out_err;
9836                 rkobj->raid_type = index;
9837                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9838                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9839                                   "%s", get_raid_name(index));
9840                 if (ret) {
9841                         kobject_put(&rkobj->kobj);
9842                         goto out_err;
9843                 }
9844                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9845         }
9846
9847         return;
9848 out_err:
9849         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
9850 }
9851
9852 static struct btrfs_block_group_cache *
9853 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
9854 {
9855         struct btrfs_block_group_cache *cache;
9856
9857         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9858         if (!cache)
9859                 return NULL;
9860
9861         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9862                                         GFP_NOFS);
9863         if (!cache->free_space_ctl) {
9864                 kfree(cache);
9865                 return NULL;
9866         }
9867
9868         cache->key.objectid = start;
9869         cache->key.offset = size;
9870         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9871
9872         cache->sectorsize = root->sectorsize;
9873         cache->fs_info = root->fs_info;
9874         cache->full_stripe_len = btrfs_full_stripe_len(root,
9875                                                &root->fs_info->mapping_tree,
9876                                                start);
9877         set_free_space_tree_thresholds(cache);
9878
9879         atomic_set(&cache->count, 1);
9880         spin_lock_init(&cache->lock);
9881         init_rwsem(&cache->data_rwsem);
9882         INIT_LIST_HEAD(&cache->list);
9883         INIT_LIST_HEAD(&cache->cluster_list);
9884         INIT_LIST_HEAD(&cache->bg_list);
9885         INIT_LIST_HEAD(&cache->ro_list);
9886         INIT_LIST_HEAD(&cache->dirty_list);
9887         INIT_LIST_HEAD(&cache->io_list);
9888         btrfs_init_free_space_ctl(cache);
9889         atomic_set(&cache->trimming, 0);
9890         mutex_init(&cache->free_space_lock);
9891
9892         return cache;
9893 }
9894
9895 int btrfs_read_block_groups(struct btrfs_root *root)
9896 {
9897         struct btrfs_path *path;
9898         int ret;
9899         struct btrfs_block_group_cache *cache;
9900         struct btrfs_fs_info *info = root->fs_info;
9901         struct btrfs_space_info *space_info;
9902         struct btrfs_key key;
9903         struct btrfs_key found_key;
9904         struct extent_buffer *leaf;
9905         int need_clear = 0;
9906         u64 cache_gen;
9907
9908         root = info->extent_root;
9909         key.objectid = 0;
9910         key.offset = 0;
9911         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9912         path = btrfs_alloc_path();
9913         if (!path)
9914                 return -ENOMEM;
9915         path->reada = READA_FORWARD;
9916
9917         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
9918         if (btrfs_test_opt(root, SPACE_CACHE) &&
9919             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
9920                 need_clear = 1;
9921         if (btrfs_test_opt(root, CLEAR_CACHE))
9922                 need_clear = 1;
9923
9924         while (1) {
9925                 ret = find_first_block_group(root, path, &key);
9926                 if (ret > 0)
9927                         break;
9928                 if (ret != 0)
9929                         goto error;
9930
9931                 leaf = path->nodes[0];
9932                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9933
9934                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
9935                                                        found_key.offset);
9936                 if (!cache) {
9937                         ret = -ENOMEM;
9938                         goto error;
9939                 }
9940
9941                 if (need_clear) {
9942                         /*
9943                          * When we mount with old space cache, we need to
9944                          * set BTRFS_DC_CLEAR and set dirty flag.
9945                          *
9946                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9947                          *    truncate the old free space cache inode and
9948                          *    setup a new one.
9949                          * b) Setting 'dirty flag' makes sure that we flush
9950                          *    the new space cache info onto disk.
9951                          */
9952                         if (btrfs_test_opt(root, SPACE_CACHE))
9953                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9954                 }
9955
9956                 read_extent_buffer(leaf, &cache->item,
9957                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9958                                    sizeof(cache->item));
9959                 cache->flags = btrfs_block_group_flags(&cache->item);
9960
9961                 key.objectid = found_key.objectid + found_key.offset;
9962                 btrfs_release_path(path);
9963
9964                 /*
9965                  * We need to exclude the super stripes now so that the space
9966                  * info has super bytes accounted for, otherwise we'll think
9967                  * we have more space than we actually do.
9968                  */
9969                 ret = exclude_super_stripes(root, cache);
9970                 if (ret) {
9971                         /*
9972                          * We may have excluded something, so call this just in
9973                          * case.
9974                          */
9975                         free_excluded_extents(root, cache);
9976                         btrfs_put_block_group(cache);
9977                         goto error;
9978                 }
9979
9980                 /*
9981                  * check for two cases, either we are full, and therefore
9982                  * don't need to bother with the caching work since we won't
9983                  * find any space, or we are empty, and we can just add all
9984                  * the space in and be done with it.  This saves us _alot_ of
9985                  * time, particularly in the full case.
9986                  */
9987                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
9988                         cache->last_byte_to_unpin = (u64)-1;
9989                         cache->cached = BTRFS_CACHE_FINISHED;
9990                         free_excluded_extents(root, cache);
9991                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9992                         cache->last_byte_to_unpin = (u64)-1;
9993                         cache->cached = BTRFS_CACHE_FINISHED;
9994                         add_new_free_space(cache, root->fs_info,
9995                                            found_key.objectid,
9996                                            found_key.objectid +
9997                                            found_key.offset);
9998                         free_excluded_extents(root, cache);
9999                 }
10000
10001                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
10002                 if (ret) {
10003                         btrfs_remove_free_space_cache(cache);
10004                         btrfs_put_block_group(cache);
10005                         goto error;
10006                 }
10007
10008                 ret = update_space_info(info, cache->flags, found_key.offset,
10009                                         btrfs_block_group_used(&cache->item),
10010                                         &space_info);
10011                 if (ret) {
10012                         btrfs_remove_free_space_cache(cache);
10013                         spin_lock(&info->block_group_cache_lock);
10014                         rb_erase(&cache->cache_node,
10015                                  &info->block_group_cache_tree);
10016                         RB_CLEAR_NODE(&cache->cache_node);
10017                         spin_unlock(&info->block_group_cache_lock);
10018                         btrfs_put_block_group(cache);
10019                         goto error;
10020                 }
10021
10022                 cache->space_info = space_info;
10023                 spin_lock(&cache->space_info->lock);
10024                 cache->space_info->bytes_readonly += cache->bytes_super;
10025                 spin_unlock(&cache->space_info->lock);
10026
10027                 __link_block_group(space_info, cache);
10028
10029                 set_avail_alloc_bits(root->fs_info, cache->flags);
10030                 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
10031                         inc_block_group_ro(cache, 1);
10032                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10033                         spin_lock(&info->unused_bgs_lock);
10034                         /* Should always be true but just in case. */
10035                         if (list_empty(&cache->bg_list)) {
10036                                 btrfs_get_block_group(cache);
10037                                 list_add_tail(&cache->bg_list,
10038                                               &info->unused_bgs);
10039                         }
10040                         spin_unlock(&info->unused_bgs_lock);
10041                 }
10042         }
10043
10044         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
10045                 if (!(get_alloc_profile(root, space_info->flags) &
10046                       (BTRFS_BLOCK_GROUP_RAID10 |
10047                        BTRFS_BLOCK_GROUP_RAID1 |
10048                        BTRFS_BLOCK_GROUP_RAID5 |
10049                        BTRFS_BLOCK_GROUP_RAID6 |
10050                        BTRFS_BLOCK_GROUP_DUP)))
10051                         continue;
10052                 /*
10053                  * avoid allocating from un-mirrored block group if there are
10054                  * mirrored block groups.
10055                  */
10056                 list_for_each_entry(cache,
10057                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10058                                 list)
10059                         inc_block_group_ro(cache, 1);
10060                 list_for_each_entry(cache,
10061                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10062                                 list)
10063                         inc_block_group_ro(cache, 1);
10064         }
10065
10066         init_global_block_rsv(info);
10067         ret = 0;
10068 error:
10069         btrfs_free_path(path);
10070         return ret;
10071 }
10072
10073 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10074                                        struct btrfs_root *root)
10075 {
10076         struct btrfs_block_group_cache *block_group, *tmp;
10077         struct btrfs_root *extent_root = root->fs_info->extent_root;
10078         struct btrfs_block_group_item item;
10079         struct btrfs_key key;
10080         int ret = 0;
10081         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10082
10083         trans->can_flush_pending_bgs = false;
10084         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10085                 if (ret)
10086                         goto next;
10087
10088                 spin_lock(&block_group->lock);
10089                 memcpy(&item, &block_group->item, sizeof(item));
10090                 memcpy(&key, &block_group->key, sizeof(key));
10091                 spin_unlock(&block_group->lock);
10092
10093                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10094                                         sizeof(item));
10095                 if (ret)
10096                         btrfs_abort_transaction(trans, extent_root, ret);
10097                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
10098                                                key.objectid, key.offset);
10099                 if (ret)
10100                         btrfs_abort_transaction(trans, extent_root, ret);
10101                 add_block_group_free_space(trans, root->fs_info, block_group);
10102                 /* already aborted the transaction if it failed. */
10103 next:
10104                 list_del_init(&block_group->bg_list);
10105         }
10106         trans->can_flush_pending_bgs = can_flush_pending_bgs;
10107 }
10108
10109 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10110                            struct btrfs_root *root, u64 bytes_used,
10111                            u64 type, u64 chunk_objectid, u64 chunk_offset,
10112                            u64 size)
10113 {
10114         int ret;
10115         struct btrfs_root *extent_root;
10116         struct btrfs_block_group_cache *cache;
10117
10118         extent_root = root->fs_info->extent_root;
10119
10120         btrfs_set_log_full_commit(root->fs_info, trans);
10121
10122         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
10123         if (!cache)
10124                 return -ENOMEM;
10125
10126         btrfs_set_block_group_used(&cache->item, bytes_used);
10127         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
10128         btrfs_set_block_group_flags(&cache->item, type);
10129
10130         cache->flags = type;
10131         cache->last_byte_to_unpin = (u64)-1;
10132         cache->cached = BTRFS_CACHE_FINISHED;
10133         cache->needs_free_space = 1;
10134         ret = exclude_super_stripes(root, cache);
10135         if (ret) {
10136                 /*
10137                  * We may have excluded something, so call this just in
10138                  * case.
10139                  */
10140                 free_excluded_extents(root, cache);
10141                 btrfs_put_block_group(cache);
10142                 return ret;
10143         }
10144
10145         add_new_free_space(cache, root->fs_info, chunk_offset,
10146                            chunk_offset + size);
10147
10148         free_excluded_extents(root, cache);
10149
10150 #ifdef CONFIG_BTRFS_DEBUG
10151         if (btrfs_should_fragment_free_space(root, cache)) {
10152                 u64 new_bytes_used = size - bytes_used;
10153
10154                 bytes_used += new_bytes_used >> 1;
10155                 fragment_free_space(root, cache);
10156         }
10157 #endif
10158         /*
10159          * Call to ensure the corresponding space_info object is created and
10160          * assigned to our block group, but don't update its counters just yet.
10161          * We want our bg to be added to the rbtree with its ->space_info set.
10162          */
10163         ret = update_space_info(root->fs_info, cache->flags, 0, 0,
10164                                 &cache->space_info);
10165         if (ret) {
10166                 btrfs_remove_free_space_cache(cache);
10167                 btrfs_put_block_group(cache);
10168                 return ret;
10169         }
10170
10171         ret = btrfs_add_block_group_cache(root->fs_info, cache);
10172         if (ret) {
10173                 btrfs_remove_free_space_cache(cache);
10174                 btrfs_put_block_group(cache);
10175                 return ret;
10176         }
10177
10178         /*
10179          * Now that our block group has its ->space_info set and is inserted in
10180          * the rbtree, update the space info's counters.
10181          */
10182         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
10183                                 &cache->space_info);
10184         if (ret) {
10185                 btrfs_remove_free_space_cache(cache);
10186                 spin_lock(&root->fs_info->block_group_cache_lock);
10187                 rb_erase(&cache->cache_node,
10188                          &root->fs_info->block_group_cache_tree);
10189                 RB_CLEAR_NODE(&cache->cache_node);
10190                 spin_unlock(&root->fs_info->block_group_cache_lock);
10191                 btrfs_put_block_group(cache);
10192                 return ret;
10193         }
10194         update_global_block_rsv(root->fs_info);
10195
10196         spin_lock(&cache->space_info->lock);
10197         cache->space_info->bytes_readonly += cache->bytes_super;
10198         spin_unlock(&cache->space_info->lock);
10199
10200         __link_block_group(cache->space_info, cache);
10201
10202         list_add_tail(&cache->bg_list, &trans->new_bgs);
10203
10204         set_avail_alloc_bits(extent_root->fs_info, type);
10205
10206         return 0;
10207 }
10208
10209 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10210 {
10211         u64 extra_flags = chunk_to_extended(flags) &
10212                                 BTRFS_EXTENDED_PROFILE_MASK;
10213
10214         write_seqlock(&fs_info->profiles_lock);
10215         if (flags & BTRFS_BLOCK_GROUP_DATA)
10216                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10217         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10218                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10219         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10220                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10221         write_sequnlock(&fs_info->profiles_lock);
10222 }
10223
10224 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10225                              struct btrfs_root *root, u64 group_start,
10226                              struct extent_map *em)
10227 {
10228         struct btrfs_path *path;
10229         struct btrfs_block_group_cache *block_group;
10230         struct btrfs_free_cluster *cluster;
10231         struct btrfs_root *tree_root = root->fs_info->tree_root;
10232         struct btrfs_key key;
10233         struct inode *inode;
10234         struct kobject *kobj = NULL;
10235         int ret;
10236         int index;
10237         int factor;
10238         struct btrfs_caching_control *caching_ctl = NULL;
10239         bool remove_em;
10240
10241         root = root->fs_info->extent_root;
10242
10243         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
10244         BUG_ON(!block_group);
10245         BUG_ON(!block_group->ro);
10246
10247         /*
10248          * Free the reserved super bytes from this block group before
10249          * remove it.
10250          */
10251         free_excluded_extents(root, block_group);
10252
10253         memcpy(&key, &block_group->key, sizeof(key));
10254         index = get_block_group_index(block_group);
10255         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10256                                   BTRFS_BLOCK_GROUP_RAID1 |
10257                                   BTRFS_BLOCK_GROUP_RAID10))
10258                 factor = 2;
10259         else
10260                 factor = 1;
10261
10262         /* make sure this block group isn't part of an allocation cluster */
10263         cluster = &root->fs_info->data_alloc_cluster;
10264         spin_lock(&cluster->refill_lock);
10265         btrfs_return_cluster_to_free_space(block_group, cluster);
10266         spin_unlock(&cluster->refill_lock);
10267
10268         /*
10269          * make sure this block group isn't part of a metadata
10270          * allocation cluster
10271          */
10272         cluster = &root->fs_info->meta_alloc_cluster;
10273         spin_lock(&cluster->refill_lock);
10274         btrfs_return_cluster_to_free_space(block_group, cluster);
10275         spin_unlock(&cluster->refill_lock);
10276
10277         path = btrfs_alloc_path();
10278         if (!path) {
10279                 ret = -ENOMEM;
10280                 goto out;
10281         }
10282
10283         /*
10284          * get the inode first so any iput calls done for the io_list
10285          * aren't the final iput (no unlinks allowed now)
10286          */
10287         inode = lookup_free_space_inode(tree_root, block_group, path);
10288
10289         mutex_lock(&trans->transaction->cache_write_mutex);
10290         /*
10291          * make sure our free spache cache IO is done before remove the
10292          * free space inode
10293          */
10294         spin_lock(&trans->transaction->dirty_bgs_lock);
10295         if (!list_empty(&block_group->io_list)) {
10296                 list_del_init(&block_group->io_list);
10297
10298                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10299
10300                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10301                 btrfs_wait_cache_io(root, trans, block_group,
10302                                     &block_group->io_ctl, path,
10303                                     block_group->key.objectid);
10304                 btrfs_put_block_group(block_group);
10305                 spin_lock(&trans->transaction->dirty_bgs_lock);
10306         }
10307
10308         if (!list_empty(&block_group->dirty_list)) {
10309                 list_del_init(&block_group->dirty_list);
10310                 btrfs_put_block_group(block_group);
10311         }
10312         spin_unlock(&trans->transaction->dirty_bgs_lock);
10313         mutex_unlock(&trans->transaction->cache_write_mutex);
10314
10315         if (!IS_ERR(inode)) {
10316                 ret = btrfs_orphan_add(trans, inode);
10317                 if (ret) {
10318                         btrfs_add_delayed_iput(inode);
10319                         goto out;
10320                 }
10321                 clear_nlink(inode);
10322                 /* One for the block groups ref */
10323                 spin_lock(&block_group->lock);
10324                 if (block_group->iref) {
10325                         block_group->iref = 0;
10326                         block_group->inode = NULL;
10327                         spin_unlock(&block_group->lock);
10328                         iput(inode);
10329                 } else {
10330                         spin_unlock(&block_group->lock);
10331                 }
10332                 /* One for our lookup ref */
10333                 btrfs_add_delayed_iput(inode);
10334         }
10335
10336         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10337         key.offset = block_group->key.objectid;
10338         key.type = 0;
10339
10340         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10341         if (ret < 0)
10342                 goto out;
10343         if (ret > 0)
10344                 btrfs_release_path(path);
10345         if (ret == 0) {
10346                 ret = btrfs_del_item(trans, tree_root, path);
10347                 if (ret)
10348                         goto out;
10349                 btrfs_release_path(path);
10350         }
10351
10352         spin_lock(&root->fs_info->block_group_cache_lock);
10353         rb_erase(&block_group->cache_node,
10354                  &root->fs_info->block_group_cache_tree);
10355         RB_CLEAR_NODE(&block_group->cache_node);
10356
10357         if (root->fs_info->first_logical_byte == block_group->key.objectid)
10358                 root->fs_info->first_logical_byte = (u64)-1;
10359         spin_unlock(&root->fs_info->block_group_cache_lock);
10360
10361         down_write(&block_group->space_info->groups_sem);
10362         /*
10363          * we must use list_del_init so people can check to see if they
10364          * are still on the list after taking the semaphore
10365          */
10366         list_del_init(&block_group->list);
10367         if (list_empty(&block_group->space_info->block_groups[index])) {
10368                 kobj = block_group->space_info->block_group_kobjs[index];
10369                 block_group->space_info->block_group_kobjs[index] = NULL;
10370                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
10371         }
10372         up_write(&block_group->space_info->groups_sem);
10373         if (kobj) {
10374                 kobject_del(kobj);
10375                 kobject_put(kobj);
10376         }
10377
10378         if (block_group->has_caching_ctl)
10379                 caching_ctl = get_caching_control(block_group);
10380         if (block_group->cached == BTRFS_CACHE_STARTED)
10381                 wait_block_group_cache_done(block_group);
10382         if (block_group->has_caching_ctl) {
10383                 down_write(&root->fs_info->commit_root_sem);
10384                 if (!caching_ctl) {
10385                         struct btrfs_caching_control *ctl;
10386
10387                         list_for_each_entry(ctl,
10388                                     &root->fs_info->caching_block_groups, list)
10389                                 if (ctl->block_group == block_group) {
10390                                         caching_ctl = ctl;
10391                                         atomic_inc(&caching_ctl->count);
10392                                         break;
10393                                 }
10394                 }
10395                 if (caching_ctl)
10396                         list_del_init(&caching_ctl->list);
10397                 up_write(&root->fs_info->commit_root_sem);
10398                 if (caching_ctl) {
10399                         /* Once for the caching bgs list and once for us. */
10400                         put_caching_control(caching_ctl);
10401                         put_caching_control(caching_ctl);
10402                 }
10403         }
10404
10405         spin_lock(&trans->transaction->dirty_bgs_lock);
10406         if (!list_empty(&block_group->dirty_list)) {
10407                 WARN_ON(1);
10408         }
10409         if (!list_empty(&block_group->io_list)) {
10410                 WARN_ON(1);
10411         }
10412         spin_unlock(&trans->transaction->dirty_bgs_lock);
10413         btrfs_remove_free_space_cache(block_group);
10414
10415         spin_lock(&block_group->space_info->lock);
10416         list_del_init(&block_group->ro_list);
10417
10418         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
10419                 WARN_ON(block_group->space_info->total_bytes
10420                         < block_group->key.offset);
10421                 WARN_ON(block_group->space_info->bytes_readonly
10422                         < block_group->key.offset);
10423                 WARN_ON(block_group->space_info->disk_total
10424                         < block_group->key.offset * factor);
10425         }
10426         block_group->space_info->total_bytes -= block_group->key.offset;
10427         block_group->space_info->bytes_readonly -= block_group->key.offset;
10428         block_group->space_info->disk_total -= block_group->key.offset * factor;
10429
10430         spin_unlock(&block_group->space_info->lock);
10431
10432         memcpy(&key, &block_group->key, sizeof(key));
10433
10434         lock_chunks(root);
10435         if (!list_empty(&em->list)) {
10436                 /* We're in the transaction->pending_chunks list. */
10437                 free_extent_map(em);
10438         }
10439         spin_lock(&block_group->lock);
10440         block_group->removed = 1;
10441         /*
10442          * At this point trimming can't start on this block group, because we
10443          * removed the block group from the tree fs_info->block_group_cache_tree
10444          * so no one can't find it anymore and even if someone already got this
10445          * block group before we removed it from the rbtree, they have already
10446          * incremented block_group->trimming - if they didn't, they won't find
10447          * any free space entries because we already removed them all when we
10448          * called btrfs_remove_free_space_cache().
10449          *
10450          * And we must not remove the extent map from the fs_info->mapping_tree
10451          * to prevent the same logical address range and physical device space
10452          * ranges from being reused for a new block group. This is because our
10453          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10454          * completely transactionless, so while it is trimming a range the
10455          * currently running transaction might finish and a new one start,
10456          * allowing for new block groups to be created that can reuse the same
10457          * physical device locations unless we take this special care.
10458          *
10459          * There may also be an implicit trim operation if the file system
10460          * is mounted with -odiscard. The same protections must remain
10461          * in place until the extents have been discarded completely when
10462          * the transaction commit has completed.
10463          */
10464         remove_em = (atomic_read(&block_group->trimming) == 0);
10465         /*
10466          * Make sure a trimmer task always sees the em in the pinned_chunks list
10467          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10468          * before checking block_group->removed).
10469          */
10470         if (!remove_em) {
10471                 /*
10472                  * Our em might be in trans->transaction->pending_chunks which
10473                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10474                  * and so is the fs_info->pinned_chunks list.
10475                  *
10476                  * So at this point we must be holding the chunk_mutex to avoid
10477                  * any races with chunk allocation (more specifically at
10478                  * volumes.c:contains_pending_extent()), to ensure it always
10479                  * sees the em, either in the pending_chunks list or in the
10480                  * pinned_chunks list.
10481                  */
10482                 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10483         }
10484         spin_unlock(&block_group->lock);
10485
10486         if (remove_em) {
10487                 struct extent_map_tree *em_tree;
10488
10489                 em_tree = &root->fs_info->mapping_tree.map_tree;
10490                 write_lock(&em_tree->lock);
10491                 /*
10492                  * The em might be in the pending_chunks list, so make sure the
10493                  * chunk mutex is locked, since remove_extent_mapping() will
10494                  * delete us from that list.
10495                  */
10496                 remove_extent_mapping(em_tree, em);
10497                 write_unlock(&em_tree->lock);
10498                 /* once for the tree */
10499                 free_extent_map(em);
10500         }
10501
10502         unlock_chunks(root);
10503
10504         ret = remove_block_group_free_space(trans, root->fs_info, block_group);
10505         if (ret)
10506                 goto out;
10507
10508         btrfs_put_block_group(block_group);
10509         btrfs_put_block_group(block_group);
10510
10511         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10512         if (ret > 0)
10513                 ret = -EIO;
10514         if (ret < 0)
10515                 goto out;
10516
10517         ret = btrfs_del_item(trans, root, path);
10518 out:
10519         btrfs_free_path(path);
10520         return ret;
10521 }
10522
10523 struct btrfs_trans_handle *
10524 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10525                                      const u64 chunk_offset)
10526 {
10527         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10528         struct extent_map *em;
10529         struct map_lookup *map;
10530         unsigned int num_items;
10531
10532         read_lock(&em_tree->lock);
10533         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10534         read_unlock(&em_tree->lock);
10535         ASSERT(em && em->start == chunk_offset);
10536
10537         /*
10538          * We need to reserve 3 + N units from the metadata space info in order
10539          * to remove a block group (done at btrfs_remove_chunk() and at
10540          * btrfs_remove_block_group()), which are used for:
10541          *
10542          * 1 unit for adding the free space inode's orphan (located in the tree
10543          * of tree roots).
10544          * 1 unit for deleting the block group item (located in the extent
10545          * tree).
10546          * 1 unit for deleting the free space item (located in tree of tree
10547          * roots).
10548          * N units for deleting N device extent items corresponding to each
10549          * stripe (located in the device tree).
10550          *
10551          * In order to remove a block group we also need to reserve units in the
10552          * system space info in order to update the chunk tree (update one or
10553          * more device items and remove one chunk item), but this is done at
10554          * btrfs_remove_chunk() through a call to check_system_chunk().
10555          */
10556         map = em->map_lookup;
10557         num_items = 3 + map->num_stripes;
10558         free_extent_map(em);
10559
10560         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10561                                                            num_items, 1);
10562 }
10563
10564 /*
10565  * Process the unused_bgs list and remove any that don't have any allocated
10566  * space inside of them.
10567  */
10568 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10569 {
10570         struct btrfs_block_group_cache *block_group;
10571         struct btrfs_space_info *space_info;
10572         struct btrfs_root *root = fs_info->extent_root;
10573         struct btrfs_trans_handle *trans;
10574         int ret = 0;
10575
10576         if (!fs_info->open)
10577                 return;
10578
10579         spin_lock(&fs_info->unused_bgs_lock);
10580         while (!list_empty(&fs_info->unused_bgs)) {
10581                 u64 start, end;
10582                 int trimming;
10583
10584                 block_group = list_first_entry(&fs_info->unused_bgs,
10585                                                struct btrfs_block_group_cache,
10586                                                bg_list);
10587                 list_del_init(&block_group->bg_list);
10588
10589                 space_info = block_group->space_info;
10590
10591                 if (ret || btrfs_mixed_space_info(space_info)) {
10592                         btrfs_put_block_group(block_group);
10593                         continue;
10594                 }
10595                 spin_unlock(&fs_info->unused_bgs_lock);
10596
10597                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10598
10599                 /* Don't want to race with allocators so take the groups_sem */
10600                 down_write(&space_info->groups_sem);
10601                 spin_lock(&block_group->lock);
10602                 if (block_group->reserved ||
10603                     btrfs_block_group_used(&block_group->item) ||
10604                     block_group->ro ||
10605                     list_is_singular(&block_group->list)) {
10606                         /*
10607                          * We want to bail if we made new allocations or have
10608                          * outstanding allocations in this block group.  We do
10609                          * the ro check in case balance is currently acting on
10610                          * this block group.
10611                          */
10612                         spin_unlock(&block_group->lock);
10613                         up_write(&space_info->groups_sem);
10614                         goto next;
10615                 }
10616                 spin_unlock(&block_group->lock);
10617
10618                 /* We don't want to force the issue, only flip if it's ok. */
10619                 ret = inc_block_group_ro(block_group, 0);
10620                 up_write(&space_info->groups_sem);
10621                 if (ret < 0) {
10622                         ret = 0;
10623                         goto next;
10624                 }
10625
10626                 /*
10627                  * Want to do this before we do anything else so we can recover
10628                  * properly if we fail to join the transaction.
10629                  */
10630                 trans = btrfs_start_trans_remove_block_group(fs_info,
10631                                                      block_group->key.objectid);
10632                 if (IS_ERR(trans)) {
10633                         btrfs_dec_block_group_ro(root, block_group);
10634                         ret = PTR_ERR(trans);
10635                         goto next;
10636                 }
10637
10638                 /*
10639                  * We could have pending pinned extents for this block group,
10640                  * just delete them, we don't care about them anymore.
10641                  */
10642                 start = block_group->key.objectid;
10643                 end = start + block_group->key.offset - 1;
10644                 /*
10645                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10646                  * btrfs_finish_extent_commit(). If we are at transaction N,
10647                  * another task might be running finish_extent_commit() for the
10648                  * previous transaction N - 1, and have seen a range belonging
10649                  * to the block group in freed_extents[] before we were able to
10650                  * clear the whole block group range from freed_extents[]. This
10651                  * means that task can lookup for the block group after we
10652                  * unpinned it from freed_extents[] and removed it, leading to
10653                  * a BUG_ON() at btrfs_unpin_extent_range().
10654                  */
10655                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10656                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10657                                   EXTENT_DIRTY);
10658                 if (ret) {
10659                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10660                         btrfs_dec_block_group_ro(root, block_group);
10661                         goto end_trans;
10662                 }
10663                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10664                                   EXTENT_DIRTY);
10665                 if (ret) {
10666                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10667                         btrfs_dec_block_group_ro(root, block_group);
10668                         goto end_trans;
10669                 }
10670                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10671
10672                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10673                 spin_lock(&space_info->lock);
10674                 spin_lock(&block_group->lock);
10675
10676                 space_info->bytes_pinned -= block_group->pinned;
10677                 space_info->bytes_readonly += block_group->pinned;
10678                 percpu_counter_add(&space_info->total_bytes_pinned,
10679                                    -block_group->pinned);
10680                 block_group->pinned = 0;
10681
10682                 spin_unlock(&block_group->lock);
10683                 spin_unlock(&space_info->lock);
10684
10685                 /* DISCARD can flip during remount */
10686                 trimming = btrfs_test_opt(root, DISCARD);
10687
10688                 /* Implicit trim during transaction commit. */
10689                 if (trimming)
10690                         btrfs_get_block_group_trimming(block_group);
10691
10692                 /*
10693                  * Btrfs_remove_chunk will abort the transaction if things go
10694                  * horribly wrong.
10695                  */
10696                 ret = btrfs_remove_chunk(trans, root,
10697                                          block_group->key.objectid);
10698
10699                 if (ret) {
10700                         if (trimming)
10701                                 btrfs_put_block_group_trimming(block_group);
10702                         goto end_trans;
10703                 }
10704
10705                 /*
10706                  * If we're not mounted with -odiscard, we can just forget
10707                  * about this block group. Otherwise we'll need to wait
10708                  * until transaction commit to do the actual discard.
10709                  */
10710                 if (trimming) {
10711                         spin_lock(&fs_info->unused_bgs_lock);
10712                         /*
10713                          * A concurrent scrub might have added us to the list
10714                          * fs_info->unused_bgs, so use a list_move operation
10715                          * to add the block group to the deleted_bgs list.
10716                          */
10717                         list_move(&block_group->bg_list,
10718                                   &trans->transaction->deleted_bgs);
10719                         spin_unlock(&fs_info->unused_bgs_lock);
10720                         btrfs_get_block_group(block_group);
10721                 }
10722 end_trans:
10723                 btrfs_end_transaction(trans, root);
10724 next:
10725                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10726                 btrfs_put_block_group(block_group);
10727                 spin_lock(&fs_info->unused_bgs_lock);
10728         }
10729         spin_unlock(&fs_info->unused_bgs_lock);
10730 }
10731
10732 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10733 {
10734         struct btrfs_space_info *space_info;
10735         struct btrfs_super_block *disk_super;
10736         u64 features;
10737         u64 flags;
10738         int mixed = 0;
10739         int ret;
10740
10741         disk_super = fs_info->super_copy;
10742         if (!btrfs_super_root(disk_super))
10743                 return -EINVAL;
10744
10745         features = btrfs_super_incompat_flags(disk_super);
10746         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10747                 mixed = 1;
10748
10749         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10750         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10751         if (ret)
10752                 goto out;
10753
10754         if (mixed) {
10755                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10756                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10757         } else {
10758                 flags = BTRFS_BLOCK_GROUP_METADATA;
10759                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10760                 if (ret)
10761                         goto out;
10762
10763                 flags = BTRFS_BLOCK_GROUP_DATA;
10764                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10765         }
10766 out:
10767         return ret;
10768 }
10769
10770 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10771 {
10772         return unpin_extent_range(root, start, end, false);
10773 }
10774
10775 /*
10776  * It used to be that old block groups would be left around forever.
10777  * Iterating over them would be enough to trim unused space.  Since we
10778  * now automatically remove them, we also need to iterate over unallocated
10779  * space.
10780  *
10781  * We don't want a transaction for this since the discard may take a
10782  * substantial amount of time.  We don't require that a transaction be
10783  * running, but we do need to take a running transaction into account
10784  * to ensure that we're not discarding chunks that were released in
10785  * the current transaction.
10786  *
10787  * Holding the chunks lock will prevent other threads from allocating
10788  * or releasing chunks, but it won't prevent a running transaction
10789  * from committing and releasing the memory that the pending chunks
10790  * list head uses.  For that, we need to take a reference to the
10791  * transaction.
10792  */
10793 static int btrfs_trim_free_extents(struct btrfs_device *device,
10794                                    u64 minlen, u64 *trimmed)
10795 {
10796         u64 start = 0, len = 0;
10797         int ret;
10798
10799         *trimmed = 0;
10800
10801         /* Not writeable = nothing to do. */
10802         if (!device->writeable)
10803                 return 0;
10804
10805         /* No free space = nothing to do. */
10806         if (device->total_bytes <= device->bytes_used)
10807                 return 0;
10808
10809         ret = 0;
10810
10811         while (1) {
10812                 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
10813                 struct btrfs_transaction *trans;
10814                 u64 bytes;
10815
10816                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10817                 if (ret)
10818                         return ret;
10819
10820                 down_read(&fs_info->commit_root_sem);
10821
10822                 spin_lock(&fs_info->trans_lock);
10823                 trans = fs_info->running_transaction;
10824                 if (trans)
10825                         atomic_inc(&trans->use_count);
10826                 spin_unlock(&fs_info->trans_lock);
10827
10828                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10829                                                  &start, &len);
10830                 if (trans)
10831                         btrfs_put_transaction(trans);
10832
10833                 if (ret) {
10834                         up_read(&fs_info->commit_root_sem);
10835                         mutex_unlock(&fs_info->chunk_mutex);
10836                         if (ret == -ENOSPC)
10837                                 ret = 0;
10838                         break;
10839                 }
10840
10841                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10842                 up_read(&fs_info->commit_root_sem);
10843                 mutex_unlock(&fs_info->chunk_mutex);
10844
10845                 if (ret)
10846                         break;
10847
10848                 start += len;
10849                 *trimmed += bytes;
10850
10851                 if (fatal_signal_pending(current)) {
10852                         ret = -ERESTARTSYS;
10853                         break;
10854                 }
10855
10856                 cond_resched();
10857         }
10858
10859         return ret;
10860 }
10861
10862 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
10863 {
10864         struct btrfs_fs_info *fs_info = root->fs_info;
10865         struct btrfs_block_group_cache *cache = NULL;
10866         struct btrfs_device *device;
10867         struct list_head *devices;
10868         u64 group_trimmed;
10869         u64 start;
10870         u64 end;
10871         u64 trimmed = 0;
10872         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10873         int ret = 0;
10874
10875         /*
10876          * try to trim all FS space, our block group may start from non-zero.
10877          */
10878         if (range->len == total_bytes)
10879                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10880         else
10881                 cache = btrfs_lookup_block_group(fs_info, range->start);
10882
10883         while (cache) {
10884                 if (cache->key.objectid >= (range->start + range->len)) {
10885                         btrfs_put_block_group(cache);
10886                         break;
10887                 }
10888
10889                 start = max(range->start, cache->key.objectid);
10890                 end = min(range->start + range->len,
10891                                 cache->key.objectid + cache->key.offset);
10892
10893                 if (end - start >= range->minlen) {
10894                         if (!block_group_cache_done(cache)) {
10895                                 ret = cache_block_group(cache, 0);
10896                                 if (ret) {
10897                                         btrfs_put_block_group(cache);
10898                                         break;
10899                                 }
10900                                 ret = wait_block_group_cache_done(cache);
10901                                 if (ret) {
10902                                         btrfs_put_block_group(cache);
10903                                         break;
10904                                 }
10905                         }
10906                         ret = btrfs_trim_block_group(cache,
10907                                                      &group_trimmed,
10908                                                      start,
10909                                                      end,
10910                                                      range->minlen);
10911
10912                         trimmed += group_trimmed;
10913                         if (ret) {
10914                                 btrfs_put_block_group(cache);
10915                                 break;
10916                         }
10917                 }
10918
10919                 cache = next_block_group(fs_info->tree_root, cache);
10920         }
10921
10922         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
10923         devices = &root->fs_info->fs_devices->alloc_list;
10924         list_for_each_entry(device, devices, dev_alloc_list) {
10925                 ret = btrfs_trim_free_extents(device, range->minlen,
10926                                               &group_trimmed);
10927                 if (ret)
10928                         break;
10929
10930                 trimmed += group_trimmed;
10931         }
10932         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
10933
10934         range->len = trimmed;
10935         return ret;
10936 }
10937
10938 /*
10939  * btrfs_{start,end}_write_no_snapshoting() are similar to
10940  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10941  * data into the page cache through nocow before the subvolume is snapshoted,
10942  * but flush the data into disk after the snapshot creation, or to prevent
10943  * operations while snapshoting is ongoing and that cause the snapshot to be
10944  * inconsistent (writes followed by expanding truncates for example).
10945  */
10946 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
10947 {
10948         percpu_counter_dec(&root->subv_writers->counter);
10949         /*
10950          * Make sure counter is updated before we wake up waiters.
10951          */
10952         smp_mb();
10953         if (waitqueue_active(&root->subv_writers->wait))
10954                 wake_up(&root->subv_writers->wait);
10955 }
10956
10957 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
10958 {
10959         if (atomic_read(&root->will_be_snapshoted))
10960                 return 0;
10961
10962         percpu_counter_inc(&root->subv_writers->counter);
10963         /*
10964          * Make sure counter is updated before we check for snapshot creation.
10965          */
10966         smp_mb();
10967         if (atomic_read(&root->will_be_snapshoted)) {
10968                 btrfs_end_write_no_snapshoting(root);
10969                 return 0;
10970         }
10971         return 1;
10972 }
10973
10974 static int wait_snapshoting_atomic_t(atomic_t *a)
10975 {
10976         schedule();
10977         return 0;
10978 }
10979
10980 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
10981 {
10982         while (true) {
10983                 int ret;
10984
10985                 ret = btrfs_start_write_no_snapshoting(root);
10986                 if (ret)
10987                         break;
10988                 wait_on_atomic_t(&root->will_be_snapshoted,
10989                                  wait_snapshoting_atomic_t,
10990                                  TASK_UNINTERRUPTIBLE);
10991         }
10992 }