fs/btrfs/extent-tree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/signal.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/writeback.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/sort.h>
  12 #include <linux/rcupdate.h>
  13 #include <linux/kthread.h>
  14 #include <linux/slab.h>
  15 #include <linux/ratelimit.h>
  16 #include <linux/percpu_counter.h>
  17 #include <linux/lockdep.h>
  18 #include <linux/crc32c.h>
  19 #include "tree-log.h"
  20 #include "disk-io.h"
  21 #include "print-tree.h"
  22 #include "volumes.h"
  23 #include "raid56.h"
  24 #include "locking.h"
  25 #include "free-space-cache.h"
  26 #include "free-space-tree.h"
  27 #include "math.h"
  28 #include "sysfs.h"
  29 #include "qgroup.h"
  30 #include "ref-verify.h"
  31
  32 #undef SCRAMBLE_DELAYED_REFS
  33
  34 /*
  35  * control flags for do_chunk_alloc's force field
  36  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  37  * if we really need one.
  38  *
  39  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  40  * if we have very few chunks already allocated.  This is
  41  * used as part of the clustering code to help make sure
  42  * we have a good pool of storage to cluster in, without
  43  * filling the FS with empty chunks
  44  *
  45  * CHUNK_ALLOC_FORCE means it must try to allocate one
  46  *
  47  */
  48 enum {
  49         CHUNK_ALLOC_NO_FORCE = 0,
  50         CHUNK_ALLOC_LIMITED = 1,
  51         CHUNK_ALLOC_FORCE = 2,
  52 };
  53
  54 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  55                                struct btrfs_delayed_ref_node *node, u64 parent,
  56                                u64 root_objectid, u64 owner_objectid,
  57                                u64 owner_offset, int refs_to_drop,
  58                                struct btrfs_delayed_extent_op *extra_op);
  59 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  60                                     struct extent_buffer *leaf,
  61                                     struct btrfs_extent_item *ei);
  62 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  63                                       u64 parent, u64 root_objectid,
  64                                       u64 flags, u64 owner, u64 offset,
  65                                       struct btrfs_key *ins, int ref_mod);
  66 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  67                                      struct btrfs_delayed_ref_node *node,
  68                                      struct btrfs_delayed_extent_op *extent_op);
  69 static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
  70                           int force);
  71 static int find_next_key(struct btrfs_path *path, int level,
  72                          struct btrfs_key *key);
  73 static void dump_space_info(struct btrfs_fs_info *fs_info,
  74                             struct btrfs_space_info *info, u64 bytes,
  75                             int dump_block_groups);
  76 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
  77                                u64 num_bytes);
  78 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
  79                                      struct btrfs_space_info *space_info,
  80                                      u64 num_bytes);
  81 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
  82                                      struct btrfs_space_info *space_info,
  83                                      u64 num_bytes);
  84
  85 static noinline int
  86 block_group_cache_done(struct btrfs_block_group_cache *cache)
  87 {
  88         smp_mb();
  89         return cache->cached == BTRFS_CACHE_FINISHED ||
  90                 cache->cached == BTRFS_CACHE_ERROR;
  91 }
  92
  93 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  94 {
  95         return (cache->flags & bits) == bits;
  96 }
  97
  98 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
  99 {
 100         atomic_inc(&cache->count);
 101 }
 102
 103 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 104 {
 105         if (atomic_dec_and_test(&cache->count)) {
 106                 WARN_ON(cache->pinned > 0);
 107                 WARN_ON(cache->reserved > 0);
 108
 109                 /*
 110                  * If not empty, someone is still holding mutex of
 111                  * full_stripe_lock, which can only be released by caller.
 112                  * And it will definitely cause use-after-free when caller
 113                  * tries to release full stripe lock.
 114                  *
 115                  * No better way to resolve, but only to warn.
 116                  */
 117                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 118                 kfree(cache->free_space_ctl);
 119                 kfree(cache);
 120         }
 121 }
 122
 123 /*
 124  * this adds the block group to the fs_info rb tree for the block group
 125  * cache
 126  */
 127 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 128                                 struct btrfs_block_group_cache *block_group)
 129 {
 130         struct rb_node **p;
 131         struct rb_node *parent = NULL;
 132         struct btrfs_block_group_cache *cache;
 133
 134         spin_lock(&info->block_group_cache_lock);
 135         p = &info->block_group_cache_tree.rb_node;
 136
 137         while (*p) {
 138                 parent = *p;
 139                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 140                                  cache_node);
 141                 if (block_group->key.objectid < cache->key.objectid) {
 142                         p = &(*p)->rb_left;
 143                 } else if (block_group->key.objectid > cache->key.objectid) {
 144                         p = &(*p)->rb_right;
 145                 } else {
 146                         spin_unlock(&info->block_group_cache_lock);
 147                         return -EEXIST;
 148                 }
 149         }
 150
 151         rb_link_node(&block_group->cache_node, parent, p);
 152         rb_insert_color(&block_group->cache_node,
 153                         &info->block_group_cache_tree);
 154
 155         if (info->first_logical_byte > block_group->key.objectid)
 156                 info->first_logical_byte = block_group->key.objectid;
 157
 158         spin_unlock(&info->block_group_cache_lock);
 159
 160         return 0;
 161 }
 162
 163 /*
 164  * This will return the block group at or after bytenr if contains is 0, else
 165  * it will return the block group that contains the bytenr
 166  */
 167 static struct btrfs_block_group_cache *
 168 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 169                               int contains)
 170 {
 171         struct btrfs_block_group_cache *cache, *ret = NULL;
 172         struct rb_node *n;
 173         u64 end, start;
 174
 175         spin_lock(&info->block_group_cache_lock);
 176         n = info->block_group_cache_tree.rb_node;
 177
 178         while (n) {
 179                 cache = rb_entry(n, struct btrfs_block_group_cache,
 180                                  cache_node);
 181                 end = cache->key.objectid + cache->key.offset - 1;
 182                 start = cache->key.objectid;
 183
 184                 if (bytenr < start) {
 185                         if (!contains && (!ret || start < ret->key.objectid))
 186                                 ret = cache;
 187                         n = n->rb_left;
 188                 } else if (bytenr > start) {
 189                         if (contains && bytenr <= end) {
 190                                 ret = cache;
 191                                 break;
 192                         }
 193                         n = n->rb_right;
 194                 } else {
 195                         ret = cache;
 196                         break;
 197                 }
 198         }
 199         if (ret) {
 200                 btrfs_get_block_group(ret);
 201                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 202                         info->first_logical_byte = ret->key.objectid;
 203         }
 204         spin_unlock(&info->block_group_cache_lock);
 205
 206         return ret;
 207 }
 208
 209 static int add_excluded_extent(struct btrfs_fs_info *fs_info,
 210                                u64 start, u64 num_bytes)
 211 {
 212         u64 end = start + num_bytes - 1;
 213         set_extent_bits(&fs_info->freed_extents[0],
 214                         start, end, EXTENT_UPTODATE);
 215         set_extent_bits(&fs_info->freed_extents[1],
 216                         start, end, EXTENT_UPTODATE);
 217         return 0;
 218 }
 219
 220 static void free_excluded_extents(struct btrfs_block_group_cache *cache)
 221 {
 222         struct btrfs_fs_info *fs_info = cache->fs_info;
 223         u64 start, end;
 224
 225         start = cache->key.objectid;
 226         end = start + cache->key.offset - 1;
 227
 228         clear_extent_bits(&fs_info->freed_extents[0],
 229                           start, end, EXTENT_UPTODATE);
 230         clear_extent_bits(&fs_info->freed_extents[1],
 231                           start, end, EXTENT_UPTODATE);
 232 }
 233
 234 static int exclude_super_stripes(struct btrfs_block_group_cache *cache)
 235 {
 236         struct btrfs_fs_info *fs_info = cache->fs_info;
 237         u64 bytenr;
 238         u64 *logical;
 239         int stripe_len;
 240         int i, nr, ret;
 241
 242         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 243                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 244                 cache->bytes_super += stripe_len;
 245                 ret = add_excluded_extent(fs_info, cache->key.objectid,
 246                                           stripe_len);
 247                 if (ret)
 248                         return ret;
 249         }
 250
 251         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 252                 bytenr = btrfs_sb_offset(i);
 253                 ret = btrfs_rmap_block(fs_info, cache->key.objectid,
 254                                        bytenr, &logical, &nr, &stripe_len);
 255                 if (ret)
 256                         return ret;
 257
 258                 while (nr--) {
 259                         u64 start, len;
 260
 261                         if (logical[nr] > cache->key.objectid +
 262                             cache->key.offset)
 263                                 continue;
 264
 265                         if (logical[nr] + stripe_len <= cache->key.objectid)
 266                                 continue;
 267
 268                         start = logical[nr];
 269                         if (start < cache->key.objectid) {
 270                                 start = cache->key.objectid;
 271                                 len = (logical[nr] + stripe_len) - start;
 272                         } else {
 273                                 len = min_t(u64, stripe_len,
 274                                             cache->key.objectid +
 275                                             cache->key.offset - start);
 276                         }
 277
 278                         cache->bytes_super += len;
 279                         ret = add_excluded_extent(fs_info, start, len);
 280                         if (ret) {
 281                                 kfree(logical);
 282                                 return ret;
 283                         }
 284                 }
 285
 286                 kfree(logical);
 287         }
 288         return 0;
 289 }
 290
 291 static struct btrfs_caching_control *
 292 get_caching_control(struct btrfs_block_group_cache *cache)
 293 {
 294         struct btrfs_caching_control *ctl;
 295
 296         spin_lock(&cache->lock);
 297         if (!cache->caching_ctl) {
 298                 spin_unlock(&cache->lock);
 299                 return NULL;
 300         }
 301
 302         ctl = cache->caching_ctl;
 303         refcount_inc(&ctl->count);
 304         spin_unlock(&cache->lock);
 305         return ctl;
 306 }
 307
 308 static void put_caching_control(struct btrfs_caching_control *ctl)
 309 {
 310         if (refcount_dec_and_test(&ctl->count))
 311                 kfree(ctl);
 312 }
 313
 314 #ifdef CONFIG_BTRFS_DEBUG
 315 static void fragment_free_space(struct btrfs_block_group_cache *block_group)
 316 {
 317         struct btrfs_fs_info *fs_info = block_group->fs_info;
 318         u64 start = block_group->key.objectid;
 319         u64 len = block_group->key.offset;
 320         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 321                 fs_info->nodesize : fs_info->sectorsize;
 322         u64 step = chunk << 1;
 323
 324         while (len > chunk) {
 325                 btrfs_remove_free_space(block_group, start, chunk);
 326                 start += step;
 327                 if (len < step)
 328                         len = 0;
 329                 else
 330                         len -= step;
 331         }
 332 }
 333 #endif
 334
 335 /*
 336  * this is only called by cache_block_group, since we could have freed extents
 337  * we need to check the pinned_extents for any extents that can't be used yet
 338  * since their free space will be released as soon as the transaction commits.
 339  */
 340 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 341                        u64 start, u64 end)
 342 {
 343         struct btrfs_fs_info *info = block_group->fs_info;
 344         u64 extent_start, extent_end, size, total_added = 0;
 345         int ret;
 346
 347         while (start < end) {
 348                 ret = find_first_extent_bit(info->pinned_extents, start,
 349                                             &extent_start, &extent_end,
 350                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 351                                             NULL);
 352                 if (ret)
 353                         break;
 354
 355                 if (extent_start <= start) {
 356                         start = extent_end + 1;
 357                 } else if (extent_start > start && extent_start < end) {
 358                         size = extent_start - start;
 359                         total_added += size;
 360                         ret = btrfs_add_free_space(block_group, start,
 361                                                    size);
 362                         BUG_ON(ret); /* -ENOMEM or logic error */
 363                         start = extent_end + 1;
 364                 } else {
 365                         break;
 366                 }
 367         }
 368
 369         if (start < end) {
 370                 size = end - start;
 371                 total_added += size;
 372                 ret = btrfs_add_free_space(block_group, start, size);
 373                 BUG_ON(ret); /* -ENOMEM or logic error */
 374         }
 375
 376         return total_added;
 377 }
 378
 379 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 380 {
 381         struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
 382         struct btrfs_fs_info *fs_info = block_group->fs_info;
 383         struct btrfs_root *extent_root = fs_info->extent_root;
 384         struct btrfs_path *path;
 385         struct extent_buffer *leaf;
 386         struct btrfs_key key;
 387         u64 total_found = 0;
 388         u64 last = 0;
 389         u32 nritems;
 390         int ret;
 391         bool wakeup = true;
 392
 393         path = btrfs_alloc_path();
 394         if (!path)
 395                 return -ENOMEM;
 396
 397         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 398
 399 #ifdef CONFIG_BTRFS_DEBUG
 400         /*
 401          * If we're fragmenting we don't want to make anybody think we can
 402          * allocate from this block group until we've had a chance to fragment
 403          * the free space.
 404          */
 405         if (btrfs_should_fragment_free_space(block_group))
 406                 wakeup = false;
 407 #endif
 408         /*
 409          * We don't want to deadlock with somebody trying to allocate a new
 410          * extent for the extent root while also trying to search the extent
 411          * root to add free space.  So we skip locking and search the commit
 412          * root, since its read-only
 413          */
 414         path->skip_locking = 1;
 415         path->search_commit_root = 1;
 416         path->reada = READA_FORWARD;
 417
 418         key.objectid = last;
 419         key.offset = 0;
 420         key.type = BTRFS_EXTENT_ITEM_KEY;
 421
 422 next:
 423         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 424         if (ret < 0)
 425                 goto out;
 426
 427         leaf = path->nodes[0];
 428         nritems = btrfs_header_nritems(leaf);
 429
 430         while (1) {
 431                 if (btrfs_fs_closing(fs_info) > 1) {
 432                         last = (u64)-1;
 433                         break;
 434                 }
 435
 436                 if (path->slots[0] < nritems) {
 437                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 438                 } else {
 439                         ret = find_next_key(path, 0, &key);
 440                         if (ret)
 441                                 break;
 442
 443                         if (need_resched() ||
 444                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 445                                 if (wakeup)
 446                                         caching_ctl->progress = last;
 447                                 btrfs_release_path(path);
 448                                 up_read(&fs_info->commit_root_sem);
 449                                 mutex_unlock(&caching_ctl->mutex);
 450                                 cond_resched();
 451                                 mutex_lock(&caching_ctl->mutex);
 452                                 down_read(&fs_info->commit_root_sem);
 453                                 goto next;
 454                         }
 455
 456                         ret = btrfs_next_leaf(extent_root, path);
 457                         if (ret < 0)
 458                                 goto out;
 459                         if (ret)
 460                                 break;
 461                         leaf = path->nodes[0];
 462                         nritems = btrfs_header_nritems(leaf);
 463                         continue;
 464                 }
 465
 466                 if (key.objectid < last) {
 467                         key.objectid = last;
 468                         key.offset = 0;
 469                         key.type = BTRFS_EXTENT_ITEM_KEY;
 470
 471                         if (wakeup)
 472                                 caching_ctl->progress = last;
 473                         btrfs_release_path(path);
 474                         goto next;
 475                 }
 476
 477                 if (key.objectid < block_group->key.objectid) {
 478                         path->slots[0]++;
 479                         continue;
 480                 }
 481
 482                 if (key.objectid >= block_group->key.objectid +
 483                     block_group->key.offset)
 484                         break;
 485
 486                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 487                     key.type == BTRFS_METADATA_ITEM_KEY) {
 488                         total_found += add_new_free_space(block_group, last,
 489                                                           key.objectid);
 490                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 491                                 last = key.objectid +
 492                                         fs_info->nodesize;
 493                         else
 494                                 last = key.objectid + key.offset;
 495
 496                         if (total_found > CACHING_CTL_WAKE_UP) {
 497                                 total_found = 0;
 498                                 if (wakeup)
 499                                         wake_up(&caching_ctl->wait);
 500                         }
 501                 }
 502                 path->slots[0]++;
 503         }
 504         ret = 0;
 505
 506         total_found += add_new_free_space(block_group, last,
 507                                           block_group->key.objectid +
 508                                           block_group->key.offset);
 509         caching_ctl->progress = (u64)-1;
 510
 511 out:
 512         btrfs_free_path(path);
 513         return ret;
 514 }
 515
 516 static noinline void caching_thread(struct btrfs_work *work)
 517 {
 518         struct btrfs_block_group_cache *block_group;
 519         struct btrfs_fs_info *fs_info;
 520         struct btrfs_caching_control *caching_ctl;
 521         int ret;
 522
 523         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 524         block_group = caching_ctl->block_group;
 525         fs_info = block_group->fs_info;
 526
 527         mutex_lock(&caching_ctl->mutex);
 528         down_read(&fs_info->commit_root_sem);
 529
 530         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 531                 ret = load_free_space_tree(caching_ctl);
 532         else
 533                 ret = load_extent_tree_free(caching_ctl);
 534
 535         spin_lock(&block_group->lock);
 536         block_group->caching_ctl = NULL;
 537         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 538         spin_unlock(&block_group->lock);
 539
 540 #ifdef CONFIG_BTRFS_DEBUG
 541         if (btrfs_should_fragment_free_space(block_group)) {
 542                 u64 bytes_used;
 543
 544                 spin_lock(&block_group->space_info->lock);
 545                 spin_lock(&block_group->lock);
 546                 bytes_used = block_group->key.offset -
 547                         btrfs_block_group_used(&block_group->item);
 548                 block_group->space_info->bytes_used += bytes_used >> 1;
 549                 spin_unlock(&block_group->lock);
 550                 spin_unlock(&block_group->space_info->lock);
 551                 fragment_free_space(block_group);
 552         }
 553 #endif
 554
 555         caching_ctl->progress = (u64)-1;
 556
 557         up_read(&fs_info->commit_root_sem);
 558         free_excluded_extents(block_group);
 559         mutex_unlock(&caching_ctl->mutex);
 560
 561         wake_up(&caching_ctl->wait);
 562
 563         put_caching_control(caching_ctl);
 564         btrfs_put_block_group(block_group);
 565 }
 566
 567 static int cache_block_group(struct btrfs_block_group_cache *cache,
 568                              int load_cache_only)
 569 {
 570         DEFINE_WAIT(wait);
 571         struct btrfs_fs_info *fs_info = cache->fs_info;
 572         struct btrfs_caching_control *caching_ctl;
 573         int ret = 0;
 574
 575         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 576         if (!caching_ctl)
 577                 return -ENOMEM;
 578
 579         INIT_LIST_HEAD(&caching_ctl->list);
 580         mutex_init(&caching_ctl->mutex);
 581         init_waitqueue_head(&caching_ctl->wait);
 582         caching_ctl->block_group = cache;
 583         caching_ctl->progress = cache->key.objectid;
 584         refcount_set(&caching_ctl->count, 1);
 585         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 586                         caching_thread, NULL, NULL);
 587
 588         spin_lock(&cache->lock);
 589         /*
 590          * This should be a rare occasion, but this could happen I think in the
 591          * case where one thread starts to load the space cache info, and then
 592          * some other thread starts a transaction commit which tries to do an
 593          * allocation while the other thread is still loading the space cache
 594          * info.  The previous loop should have kept us from choosing this block
 595          * group, but if we've moved to the state where we will wait on caching
 596          * block groups we need to first check if we're doing a fast load here,
 597          * so we can wait for it to finish, otherwise we could end up allocating
 598          * from a block group who's cache gets evicted for one reason or
 599          * another.
 600          */
 601         while (cache->cached == BTRFS_CACHE_FAST) {
 602                 struct btrfs_caching_control *ctl;
 603
 604                 ctl = cache->caching_ctl;
 605                 refcount_inc(&ctl->count);
 606                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 607                 spin_unlock(&cache->lock);
 608
 609                 schedule();
 610
 611                 finish_wait(&ctl->wait, &wait);
 612                 put_caching_control(ctl);
 613                 spin_lock(&cache->lock);
 614         }
 615
 616         if (cache->cached != BTRFS_CACHE_NO) {
 617                 spin_unlock(&cache->lock);
 618                 kfree(caching_ctl);
 619                 return 0;
 620         }
 621         WARN_ON(cache->caching_ctl);
 622         cache->caching_ctl = caching_ctl;
 623         cache->cached = BTRFS_CACHE_FAST;
 624         spin_unlock(&cache->lock);
 625
 626         if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
 627                 mutex_lock(&caching_ctl->mutex);
 628                 ret = load_free_space_cache(fs_info, cache);
 629
 630                 spin_lock(&cache->lock);
 631                 if (ret == 1) {
 632                         cache->caching_ctl = NULL;
 633                         cache->cached = BTRFS_CACHE_FINISHED;
 634                         cache->last_byte_to_unpin = (u64)-1;
 635                         caching_ctl->progress = (u64)-1;
 636                 } else {
 637                         if (load_cache_only) {
 638                                 cache->caching_ctl = NULL;
 639                                 cache->cached = BTRFS_CACHE_NO;
 640                         } else {
 641                                 cache->cached = BTRFS_CACHE_STARTED;
 642                                 cache->has_caching_ctl = 1;
 643                         }
 644                 }
 645                 spin_unlock(&cache->lock);
 646 #ifdef CONFIG_BTRFS_DEBUG
 647                 if (ret == 1 &&
 648                     btrfs_should_fragment_free_space(cache)) {
 649                         u64 bytes_used;
 650
 651                         spin_lock(&cache->space_info->lock);
 652                         spin_lock(&cache->lock);
 653                         bytes_used = cache->key.offset -
 654                                 btrfs_block_group_used(&cache->item);
 655                         cache->space_info->bytes_used += bytes_used >> 1;
 656                         spin_unlock(&cache->lock);
 657                         spin_unlock(&cache->space_info->lock);
 658                         fragment_free_space(cache);
 659                 }
 660 #endif
 661                 mutex_unlock(&caching_ctl->mutex);
 662
 663                 wake_up(&caching_ctl->wait);
 664                 if (ret == 1) {
 665                         put_caching_control(caching_ctl);
 666                         free_excluded_extents(cache);
 667                         return 0;
 668                 }
 669         } else {
 670                 /*
 671                  * We're either using the free space tree or no caching at all.
 672                  * Set cached to the appropriate value and wakeup any waiters.
 673                  */
 674                 spin_lock(&cache->lock);
 675                 if (load_cache_only) {
 676                         cache->caching_ctl = NULL;
 677                         cache->cached = BTRFS_CACHE_NO;
 678                 } else {
 679                         cache->cached = BTRFS_CACHE_STARTED;
 680                         cache->has_caching_ctl = 1;
 681                 }
 682                 spin_unlock(&cache->lock);
 683                 wake_up(&caching_ctl->wait);
 684         }
 685
 686         if (load_cache_only) {
 687                 put_caching_control(caching_ctl);
 688                 return 0;
 689         }
 690
 691         down_write(&fs_info->commit_root_sem);
 692         refcount_inc(&caching_ctl->count);
 693         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 694         up_write(&fs_info->commit_root_sem);
 695
 696         btrfs_get_block_group(cache);
 697
 698         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 699
 700         return ret;
 701 }
 702
 703 /*
 704  * return the block group that starts at or after bytenr
 705  */
 706 static struct btrfs_block_group_cache *
 707 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 708 {
 709         return block_group_cache_tree_search(info, bytenr, 0);
 710 }
 711
 712 /*
 713  * return the block group that contains the given bytenr
 714  */
 715 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 716                                                  struct btrfs_fs_info *info,
 717                                                  u64 bytenr)
 718 {
 719         return block_group_cache_tree_search(info, bytenr, 1);
 720 }
 721
 722 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 723                                                   u64 flags)
 724 {
 725         struct list_head *head = &info->space_info;
 726         struct btrfs_space_info *found;
 727
 728         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 729
 730         rcu_read_lock();
 731         list_for_each_entry_rcu(found, head, list) {
 732                 if (found->flags & flags) {
 733                         rcu_read_unlock();
 734                         return found;
 735                 }
 736         }
 737         rcu_read_unlock();
 738         return NULL;
 739 }
 740
 741 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, s64 num_bytes,
 742                              bool metadata, u64 root_objectid)
 743 {
 744         struct btrfs_space_info *space_info;
 745         u64 flags;
 746
 747         if (metadata) {
 748                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
 749                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
 750                 else
 751                         flags = BTRFS_BLOCK_GROUP_METADATA;
 752         } else {
 753                 flags = BTRFS_BLOCK_GROUP_DATA;
 754         }
 755
 756         space_info = __find_space_info(fs_info, flags);
 757         ASSERT(space_info);
 758         percpu_counter_add_batch(&space_info->total_bytes_pinned, num_bytes,
 759                     BTRFS_TOTAL_BYTES_PINNED_BATCH);
 760 }
 761
 762 /*
 763  * after adding space to the filesystem, we need to clear the full flags
 764  * on all the space infos.
 765  */
 766 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 767 {
 768         struct list_head *head = &info->space_info;
 769         struct btrfs_space_info *found;
 770
 771         rcu_read_lock();
 772         list_for_each_entry_rcu(found, head, list)
 773                 found->full = 0;
 774         rcu_read_unlock();
 775 }
 776
 777 /* simple helper to search for an existing data extent at a given offset */
 778 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 779 {
 780         int ret;
 781         struct btrfs_key key;
 782         struct btrfs_path *path;
 783
 784         path = btrfs_alloc_path();
 785         if (!path)
 786                 return -ENOMEM;
 787
 788         key.objectid = start;
 789         key.offset = len;
 790         key.type = BTRFS_EXTENT_ITEM_KEY;
 791         ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 792         btrfs_free_path(path);
 793         return ret;
 794 }
 795
 796 /*
 797  * helper function to lookup reference count and flags of a tree block.
 798  *
 799  * the head node for delayed ref is used to store the sum of all the
 800  * reference count modifications queued up in the rbtree. the head
 801  * node may also store the extent flags to set. This way you can check
 802  * to see what the reference count and extent flags would be if all of
 803  * the delayed refs are not processed.
 804  */
 805 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 806                              struct btrfs_fs_info *fs_info, u64 bytenr,
 807                              u64 offset, int metadata, u64 *refs, u64 *flags)
 808 {
 809         struct btrfs_delayed_ref_head *head;
 810         struct btrfs_delayed_ref_root *delayed_refs;
 811         struct btrfs_path *path;
 812         struct btrfs_extent_item *ei;
 813         struct extent_buffer *leaf;
 814         struct btrfs_key key;
 815         u32 item_size;
 816         u64 num_refs;
 817         u64 extent_flags;
 818         int ret;
 819
 820         /*
 821          * If we don't have skinny metadata, don't bother doing anything
 822          * different
 823          */
 824         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 825                 offset = fs_info->nodesize;
 826                 metadata = 0;
 827         }
 828
 829         path = btrfs_alloc_path();
 830         if (!path)
 831                 return -ENOMEM;
 832
 833         if (!trans) {
 834                 path->skip_locking = 1;
 835                 path->search_commit_root = 1;
 836         }
 837
 838 search_again:
 839         key.objectid = bytenr;
 840         key.offset = offset;
 841         if (metadata)
 842                 key.type = BTRFS_METADATA_ITEM_KEY;
 843         else
 844                 key.type = BTRFS_EXTENT_ITEM_KEY;
 845
 846         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 847         if (ret < 0)
 848                 goto out_free;
 849
 850         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 851                 if (path->slots[0]) {
 852                         path->slots[0]--;
 853                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 854                                               path->slots[0]);
 855                         if (key.objectid == bytenr &&
 856                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 857                             key.offset == fs_info->nodesize)
 858                                 ret = 0;
 859                 }
 860         }
 861
 862         if (ret == 0) {
 863                 leaf = path->nodes[0];
 864                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 865                 if (item_size >= sizeof(*ei)) {
 866                         ei = btrfs_item_ptr(leaf, path->slots[0],
 867                                             struct btrfs_extent_item);
 868                         num_refs = btrfs_extent_refs(leaf, ei);
 869                         extent_flags = btrfs_extent_flags(leaf, ei);
 870                 } else {
 871                         ret = -EINVAL;
 872                         btrfs_print_v0_err(fs_info);
 873                         if (trans)
 874                                 btrfs_abort_transaction(trans, ret);
 875                         else
 876                                 btrfs_handle_fs_error(fs_info, ret, NULL);
 877
 878                         goto out_free;
 879                 }
 880
 881                 BUG_ON(num_refs == 0);
 882         } else {
 883                 num_refs = 0;
 884                 extent_flags = 0;
 885                 ret = 0;
 886         }
 887
 888         if (!trans)
 889                 goto out;
 890
 891         delayed_refs = &trans->transaction->delayed_refs;
 892         spin_lock(&delayed_refs->lock);
 893         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 894         if (head) {
 895                 if (!mutex_trylock(&head->mutex)) {
 896                         refcount_inc(&head->refs);
 897                         spin_unlock(&delayed_refs->lock);
 898
 899                         btrfs_release_path(path);
 900
 901                         /*
 902                          * Mutex was contended, block until it's released and try
 903                          * again
 904                          */
 905                         mutex_lock(&head->mutex);
 906                         mutex_unlock(&head->mutex);
 907                         btrfs_put_delayed_ref_head(head);
 908                         goto search_again;
 909                 }
 910                 spin_lock(&head->lock);
 911                 if (head->extent_op && head->extent_op->update_flags)
 912                         extent_flags |= head->extent_op->flags_to_set;
 913                 else
 914                         BUG_ON(num_refs == 0);
 915
 916                 num_refs += head->ref_mod;
 917                 spin_unlock(&head->lock);
 918                 mutex_unlock(&head->mutex);
 919         }
 920         spin_unlock(&delayed_refs->lock);
 921 out:
 922         WARN_ON(num_refs == 0);
 923         if (refs)
 924                 *refs = num_refs;
 925         if (flags)
 926                 *flags = extent_flags;
 927 out_free:
 928         btrfs_free_path(path);
 929         return ret;
 930 }
 931
 932 /*
 933  * Back reference rules.  Back refs have three main goals:
 934  *
 935  * 1) differentiate between all holders of references to an extent so that
 936  *    when a reference is dropped we can make sure it was a valid reference
 937  *    before freeing the extent.
 938  *
 939  * 2) Provide enough information to quickly find the holders of an extent
 940  *    if we notice a given block is corrupted or bad.
 941  *
 942  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 943  *    maintenance.  This is actually the same as #2, but with a slightly
 944  *    different use case.
 945  *
 946  * There are two kinds of back refs. The implicit back refs is optimized
 947  * for pointers in non-shared tree blocks. For a given pointer in a block,
 948  * back refs of this kind provide information about the block's owner tree
 949  * and the pointer's key. These information allow us to find the block by
 950  * b-tree searching. The full back refs is for pointers in tree blocks not
 951  * referenced by their owner trees. The location of tree block is recorded
 952  * in the back refs. Actually the full back refs is generic, and can be
 953  * used in all cases the implicit back refs is used. The major shortcoming
 954  * of the full back refs is its overhead. Every time a tree block gets
 955  * COWed, we have to update back refs entry for all pointers in it.
 956  *
 957  * For a newly allocated tree block, we use implicit back refs for
 958  * pointers in it. This means most tree related operations only involve
 959  * implicit back refs. For a tree block created in old transaction, the
 960  * only way to drop a reference to it is COW it. So we can detect the
 961  * event that tree block loses its owner tree's reference and do the
 962  * back refs conversion.
 963  *
 964  * When a tree block is COWed through a tree, there are four cases:
 965  *
 966  * The reference count of the block is one and the tree is the block's
 967  * owner tree. Nothing to do in this case.
 968  *
 969  * The reference count of the block is one and the tree is not the
 970  * block's owner tree. In this case, full back refs is used for pointers
 971  * in the block. Remove these full back refs, add implicit back refs for
 972  * every pointers in the new block.
 973  *
 974  * The reference count of the block is greater than one and the tree is
 975  * the block's owner tree. In this case, implicit back refs is used for
 976  * pointers in the block. Add full back refs for every pointers in the
 977  * block, increase lower level extents' reference counts. The original
 978  * implicit back refs are entailed to the new block.
 979  *
 980  * The reference count of the block is greater than one and the tree is
 981  * not the block's owner tree. Add implicit back refs for every pointer in
 982  * the new block, increase lower level extents' reference count.
 983  *
 984  * Back Reference Key composing:
 985  *
 986  * The key objectid corresponds to the first byte in the extent,
 987  * The key type is used to differentiate between types of back refs.
 988  * There are different meanings of the key offset for different types
 989  * of back refs.
 990  *
 991  * File extents can be referenced by:
 992  *
 993  * - multiple snapshots, subvolumes, or different generations in one subvol
 994  * - different files inside a single subvolume
 995  * - different offsets inside a file (bookend extents in file.c)
 996  *
 997  * The extent ref structure for the implicit back refs has fields for:
 998  *
 999  * - Objectid of the subvolume root
1000  * - objectid of the file holding the reference
1001  * - original offset in the file
1002  * - how many bookend extents
1003  *
1004  * The key offset for the implicit back refs is hash of the first
1005  * three fields.
1006  *
1007  * The extent ref structure for the full back refs has field for:
1008  *
1009  * - number of pointers in the tree leaf
1010  *
1011  * The key offset for the implicit back refs is the first byte of
1012  * the tree leaf
1013  *
1014  * When a file extent is allocated, The implicit back refs is used.
1015  * the fields are filled in:
1016  *
1017  *     (root_key.objectid, inode objectid, offset in file, 1)
1018  *
1019  * When a file extent is removed file truncation, we find the
1020  * corresponding implicit back refs and check the following fields:
1021  *
1022  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1023  *
1024  * Btree extents can be referenced by:
1025  *
1026  * - Different subvolumes
1027  *
1028  * Both the implicit back refs and the full back refs for tree blocks
1029  * only consist of key. The key offset for the implicit back refs is
1030  * objectid of block's owner tree. The key offset for the full back refs
1031  * is the first byte of parent block.
1032  *
1033  * When implicit back refs is used, information about the lowest key and
1034  * level of the tree block are required. These information are stored in
1035  * tree block info structure.
1036  */
1037
1038 /*
1039  * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
1040  * is_data == BTRFS_REF_TYPE_DATA, data type is requried,
1041  * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
1042  */
1043 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
1044                                      struct btrfs_extent_inline_ref *iref,
1045                                      enum btrfs_inline_ref_type is_data)
1046 {
1047         int type = btrfs_extent_inline_ref_type(eb, iref);
1048         u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
1049
1050         if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1051             type == BTRFS_SHARED_BLOCK_REF_KEY ||
1052             type == BTRFS_SHARED_DATA_REF_KEY ||
1053             type == BTRFS_EXTENT_DATA_REF_KEY) {
1054                 if (is_data == BTRFS_REF_TYPE_BLOCK) {
1055                         if (type == BTRFS_TREE_BLOCK_REF_KEY)
1056                                 return type;
1057                         if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1058                                 ASSERT(eb->fs_info);
1059                                 /*
1060                                  * Every shared one has parent tree
1061                                  * block, which must be aligned to
1062                                  * nodesize.
1063                                  */
1064                                 if (offset &&
1065                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1066                                         return type;
1067                         }
1068                 } else if (is_data == BTRFS_REF_TYPE_DATA) {
1069                         if (type == BTRFS_EXTENT_DATA_REF_KEY)
1070                                 return type;
1071                         if (type == BTRFS_SHARED_DATA_REF_KEY) {
1072                                 ASSERT(eb->fs_info);
1073                                 /*
1074                                  * Every shared one has parent tree
1075                                  * block, which must be aligned to
1076                                  * nodesize.
1077                                  */
1078                                 if (offset &&
1079                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1080                                         return type;
1081                         }
1082                 } else {
1083                         ASSERT(is_data == BTRFS_REF_TYPE_ANY);
1084                         return type;
1085                 }
1086         }
1087
1088         btrfs_print_leaf((struct extent_buffer *)eb);
1089         btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
1090                   eb->start, type);
1091         WARN_ON(1);
1092
1093         return BTRFS_REF_TYPE_INVALID;
1094 }
1095
1096 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1097 {
1098         u32 high_crc = ~(u32)0;
1099         u32 low_crc = ~(u32)0;
1100         __le64 lenum;
1101
1102         lenum = cpu_to_le64(root_objectid);
1103         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1104         lenum = cpu_to_le64(owner);
1105         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1106         lenum = cpu_to_le64(offset);
1107         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1108
1109         return ((u64)high_crc << 31) ^ (u64)low_crc;
1110 }
1111
1112 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1113                                      struct btrfs_extent_data_ref *ref)
1114 {
1115         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1116                                     btrfs_extent_data_ref_objectid(leaf, ref),
1117                                     btrfs_extent_data_ref_offset(leaf, ref));
1118 }
1119
1120 static int match_extent_data_ref(struct extent_buffer *leaf,
1121                                  struct btrfs_extent_data_ref *ref,
1122                                  u64 root_objectid, u64 owner, u64 offset)
1123 {
1124         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1125             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1126             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1127                 return 0;
1128         return 1;
1129 }
1130
1131 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1132                                            struct btrfs_path *path,
1133                                            u64 bytenr, u64 parent,
1134                                            u64 root_objectid,
1135                                            u64 owner, u64 offset)
1136 {
1137         struct btrfs_root *root = trans->fs_info->extent_root;
1138         struct btrfs_key key;
1139         struct btrfs_extent_data_ref *ref;
1140         struct extent_buffer *leaf;
1141         u32 nritems;
1142         int ret;
1143         int recow;
1144         int err = -ENOENT;
1145
1146         key.objectid = bytenr;
1147         if (parent) {
1148                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1149                 key.offset = parent;
1150         } else {
1151                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1152                 key.offset = hash_extent_data_ref(root_objectid,
1153                                                   owner, offset);
1154         }
1155 again:
1156         recow = 0;
1157         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1158         if (ret < 0) {
1159                 err = ret;
1160                 goto fail;
1161         }
1162
1163         if (parent) {
1164                 if (!ret)
1165                         return 0;
1166                 goto fail;
1167         }
1168
1169         leaf = path->nodes[0];
1170         nritems = btrfs_header_nritems(leaf);
1171         while (1) {
1172                 if (path->slots[0] >= nritems) {
1173                         ret = btrfs_next_leaf(root, path);
1174                         if (ret < 0)
1175                                 err = ret;
1176                         if (ret)
1177                                 goto fail;
1178
1179                         leaf = path->nodes[0];
1180                         nritems = btrfs_header_nritems(leaf);
1181                         recow = 1;
1182                 }
1183
1184                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1185                 if (key.objectid != bytenr ||
1186                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1187                         goto fail;
1188
1189                 ref = btrfs_item_ptr(leaf, path->slots[0],
1190                                      struct btrfs_extent_data_ref);
1191
1192                 if (match_extent_data_ref(leaf, ref, root_objectid,
1193                                           owner, offset)) {
1194                         if (recow) {
1195                                 btrfs_release_path(path);
1196                                 goto again;
1197                         }
1198                         err = 0;
1199                         break;
1200                 }
1201                 path->slots[0]++;
1202         }
1203 fail:
1204         return err;
1205 }
1206
1207 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1208                                            struct btrfs_path *path,
1209                                            u64 bytenr, u64 parent,
1210                                            u64 root_objectid, u64 owner,
1211                                            u64 offset, int refs_to_add)
1212 {
1213         struct btrfs_root *root = trans->fs_info->extent_root;
1214         struct btrfs_key key;
1215         struct extent_buffer *leaf;
1216         u32 size;
1217         u32 num_refs;
1218         int ret;
1219
1220         key.objectid = bytenr;
1221         if (parent) {
1222                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1223                 key.offset = parent;
1224                 size = sizeof(struct btrfs_shared_data_ref);
1225         } else {
1226                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1227                 key.offset = hash_extent_data_ref(root_objectid,
1228                                                   owner, offset);
1229                 size = sizeof(struct btrfs_extent_data_ref);
1230         }
1231
1232         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1233         if (ret && ret != -EEXIST)
1234                 goto fail;
1235
1236         leaf = path->nodes[0];
1237         if (parent) {
1238                 struct btrfs_shared_data_ref *ref;
1239                 ref = btrfs_item_ptr(leaf, path->slots[0],
1240                                      struct btrfs_shared_data_ref);
1241                 if (ret == 0) {
1242                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1243                 } else {
1244                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1245                         num_refs += refs_to_add;
1246                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1247                 }
1248         } else {
1249                 struct btrfs_extent_data_ref *ref;
1250                 while (ret == -EEXIST) {
1251                         ref = btrfs_item_ptr(leaf, path->slots[0],
1252                                              struct btrfs_extent_data_ref);
1253                         if (match_extent_data_ref(leaf, ref, root_objectid,
1254                                                   owner, offset))
1255                                 break;
1256                         btrfs_release_path(path);
1257                         key.offset++;
1258                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1259                                                       size);
1260                         if (ret && ret != -EEXIST)
1261                                 goto fail;
1262
1263                         leaf = path->nodes[0];
1264                 }
1265                 ref = btrfs_item_ptr(leaf, path->slots[0],
1266                                      struct btrfs_extent_data_ref);
1267                 if (ret == 0) {
1268                         btrfs_set_extent_data_ref_root(leaf, ref,
1269                                                        root_objectid);
1270                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1271                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1272                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1273                 } else {
1274                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1275                         num_refs += refs_to_add;
1276                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1277                 }
1278         }
1279         btrfs_mark_buffer_dirty(leaf);
1280         ret = 0;
1281 fail:
1282         btrfs_release_path(path);
1283         return ret;
1284 }
1285
1286 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1287                                            struct btrfs_path *path,
1288                                            int refs_to_drop, int *last_ref)
1289 {
1290         struct btrfs_key key;
1291         struct btrfs_extent_data_ref *ref1 = NULL;
1292         struct btrfs_shared_data_ref *ref2 = NULL;
1293         struct extent_buffer *leaf;
1294         u32 num_refs = 0;
1295         int ret = 0;
1296
1297         leaf = path->nodes[0];
1298         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1299
1300         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1301                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1302                                       struct btrfs_extent_data_ref);
1303                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1304         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1305                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1306                                       struct btrfs_shared_data_ref);
1307                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1308         } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
1309                 btrfs_print_v0_err(trans->fs_info);
1310                 btrfs_abort_transaction(trans, -EINVAL);
1311                 return -EINVAL;
1312         } else {
1313                 BUG();
1314         }
1315
1316         BUG_ON(num_refs < refs_to_drop);
1317         num_refs -= refs_to_drop;
1318
1319         if (num_refs == 0) {
1320                 ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
1321                 *last_ref = 1;
1322         } else {
1323                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1324                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1325                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1326                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1327                 btrfs_mark_buffer_dirty(leaf);
1328         }
1329         return ret;
1330 }
1331
1332 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1333                                           struct btrfs_extent_inline_ref *iref)
1334 {
1335         struct btrfs_key key;
1336         struct extent_buffer *leaf;
1337         struct btrfs_extent_data_ref *ref1;
1338         struct btrfs_shared_data_ref *ref2;
1339         u32 num_refs = 0;
1340         int type;
1341
1342         leaf = path->nodes[0];
1343         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1344
1345         BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
1346         if (iref) {
1347                 /*
1348                  * If type is invalid, we should have bailed out earlier than
1349                  * this call.
1350                  */
1351                 type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
1352                 ASSERT(type != BTRFS_REF_TYPE_INVALID);
1353                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1354                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1355                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1356                 } else {
1357                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1358                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1359                 }
1360         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1361                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1362                                       struct btrfs_extent_data_ref);
1363                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1364         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1365                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1366                                       struct btrfs_shared_data_ref);
1367                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1368         } else {
1369                 WARN_ON(1);
1370         }
1371         return num_refs;
1372 }
1373
1374 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1375                                           struct btrfs_path *path,
1376                                           u64 bytenr, u64 parent,
1377                                           u64 root_objectid)
1378 {
1379         struct btrfs_root *root = trans->fs_info->extent_root;
1380         struct btrfs_key key;
1381         int ret;
1382
1383         key.objectid = bytenr;
1384         if (parent) {
1385                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1386                 key.offset = parent;
1387         } else {
1388                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1389                 key.offset = root_objectid;
1390         }
1391
1392         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1393         if (ret > 0)
1394                 ret = -ENOENT;
1395         return ret;
1396 }
1397
1398 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1399                                           struct btrfs_path *path,
1400                                           u64 bytenr, u64 parent,
1401                                           u64 root_objectid)
1402 {
1403         struct btrfs_key key;
1404         int ret;
1405
1406         key.objectid = bytenr;
1407         if (parent) {
1408                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1409                 key.offset = parent;
1410         } else {
1411                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1412                 key.offset = root_objectid;
1413         }
1414
1415         ret = btrfs_insert_empty_item(trans, trans->fs_info->extent_root,
1416                                       path, &key, 0);
1417         btrfs_release_path(path);
1418         return ret;
1419 }
1420
1421 static inline int extent_ref_type(u64 parent, u64 owner)
1422 {
1423         int type;
1424         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1425                 if (parent > 0)
1426                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1427                 else
1428                         type = BTRFS_TREE_BLOCK_REF_KEY;
1429         } else {
1430                 if (parent > 0)
1431                         type = BTRFS_SHARED_DATA_REF_KEY;
1432                 else
1433                         type = BTRFS_EXTENT_DATA_REF_KEY;
1434         }
1435         return type;
1436 }
1437
1438 static int find_next_key(struct btrfs_path *path, int level,
1439                          struct btrfs_key *key)
1440
1441 {
1442         for (; level < BTRFS_MAX_LEVEL; level++) {
1443                 if (!path->nodes[level])
1444                         break;
1445                 if (path->slots[level] + 1 >=
1446                     btrfs_header_nritems(path->nodes[level]))
1447                         continue;
1448                 if (level == 0)
1449                         btrfs_item_key_to_cpu(path->nodes[level], key,
1450                                               path->slots[level] + 1);
1451                 else
1452                         btrfs_node_key_to_cpu(path->nodes[level], key,
1453                                               path->slots[level] + 1);
1454                 return 0;
1455         }
1456         return 1;
1457 }
1458
1459 /*
1460  * look for inline back ref. if back ref is found, *ref_ret is set
1461  * to the address of inline back ref, and 0 is returned.
1462  *
1463  * if back ref isn't found, *ref_ret is set to the address where it
1464  * should be inserted, and -ENOENT is returned.
1465  *
1466  * if insert is true and there are too many inline back refs, the path
1467  * points to the extent item, and -EAGAIN is returned.
1468  *
1469  * NOTE: inline back refs are ordered in the same way that back ref
1470  *       items in the tree are ordered.
1471  */
1472 static noinline_for_stack
1473 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1474                                  struct btrfs_path *path,
1475                                  struct btrfs_extent_inline_ref **ref_ret,
1476                                  u64 bytenr, u64 num_bytes,
1477                                  u64 parent, u64 root_objectid,
1478                                  u64 owner, u64 offset, int insert)
1479 {
1480         struct btrfs_fs_info *fs_info = trans->fs_info;
1481         struct btrfs_root *root = fs_info->extent_root;
1482         struct btrfs_key key;
1483         struct extent_buffer *leaf;
1484         struct btrfs_extent_item *ei;
1485         struct btrfs_extent_inline_ref *iref;
1486         u64 flags;
1487         u64 item_size;
1488         unsigned long ptr;
1489         unsigned long end;
1490         int extra_size;
1491         int type;
1492         int want;
1493         int ret;
1494         int err = 0;
1495         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
1496         int needed;
1497
1498         key.objectid = bytenr;
1499         key.type = BTRFS_EXTENT_ITEM_KEY;
1500         key.offset = num_bytes;
1501
1502         want = extent_ref_type(parent, owner);
1503         if (insert) {
1504                 extra_size = btrfs_extent_inline_ref_size(want);
1505                 path->keep_locks = 1;
1506         } else
1507                 extra_size = -1;
1508
1509         /*
1510          * Owner is our level, so we can just add one to get the level for the
1511          * block we are interested in.
1512          */
1513         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1514                 key.type = BTRFS_METADATA_ITEM_KEY;
1515                 key.offset = owner;
1516         }
1517
1518 again:
1519         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1520         if (ret < 0) {
1521                 err = ret;
1522                 goto out;
1523         }
1524
1525         /*
1526          * We may be a newly converted file system which still has the old fat
1527          * extent entries for metadata, so try and see if we have one of those.
1528          */
1529         if (ret > 0 && skinny_metadata) {
1530                 skinny_metadata = false;
1531                 if (path->slots[0]) {
1532                         path->slots[0]--;
1533                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1534                                               path->slots[0]);
1535                         if (key.objectid == bytenr &&
1536                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1537                             key.offset == num_bytes)
1538                                 ret = 0;
1539                 }
1540                 if (ret) {
1541                         key.objectid = bytenr;
1542                         key.type = BTRFS_EXTENT_ITEM_KEY;
1543                         key.offset = num_bytes;
1544                         btrfs_release_path(path);
1545                         goto again;
1546                 }
1547         }
1548
1549         if (ret && !insert) {
1550                 err = -ENOENT;
1551                 goto out;
1552         } else if (WARN_ON(ret)) {
1553                 err = -EIO;
1554                 goto out;
1555         }
1556
1557         leaf = path->nodes[0];
1558         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1559         if (unlikely(item_size < sizeof(*ei))) {
1560                 err = -EINVAL;
1561                 btrfs_print_v0_err(fs_info);
1562                 btrfs_abort_transaction(trans, err);
1563                 goto out;
1564         }
1565
1566         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1567         flags = btrfs_extent_flags(leaf, ei);
1568
1569         ptr = (unsigned long)(ei + 1);
1570         end = (unsigned long)ei + item_size;
1571
1572         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1573                 ptr += sizeof(struct btrfs_tree_block_info);
1574                 BUG_ON(ptr > end);
1575         }
1576
1577         if (owner >= BTRFS_FIRST_FREE_OBJECTID)
1578                 needed = BTRFS_REF_TYPE_DATA;
1579         else
1580                 needed = BTRFS_REF_TYPE_BLOCK;
1581
1582         err = -ENOENT;
1583         while (1) {
1584                 if (ptr >= end) {
1585                         WARN_ON(ptr > end);
1586                         break;
1587                 }
1588                 iref = (struct btrfs_extent_inline_ref *)ptr;
1589                 type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
1590                 if (type == BTRFS_REF_TYPE_INVALID) {
1591                         err = -EUCLEAN;
1592                         goto out;
1593                 }
1594
1595                 if (want < type)
1596                         break;
1597                 if (want > type) {
1598                         ptr += btrfs_extent_inline_ref_size(type);
1599                         continue;
1600                 }
1601
1602                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1603                         struct btrfs_extent_data_ref *dref;
1604                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1605                         if (match_extent_data_ref(leaf, dref, root_objectid,
1606                                                   owner, offset)) {
1607                                 err = 0;
1608                                 break;
1609                         }
1610                         if (hash_extent_data_ref_item(leaf, dref) <
1611                             hash_extent_data_ref(root_objectid, owner, offset))
1612                                 break;
1613                 } else {
1614                         u64 ref_offset;
1615                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1616                         if (parent > 0) {
1617                                 if (parent == ref_offset) {
1618                                         err = 0;
1619                                         break;
1620                                 }
1621                                 if (ref_offset < parent)
1622                                         break;
1623                         } else {
1624                                 if (root_objectid == ref_offset) {
1625                                         err = 0;
1626                                         break;
1627                                 }
1628                                 if (ref_offset < root_objectid)
1629                                         break;
1630                         }
1631                 }
1632                 ptr += btrfs_extent_inline_ref_size(type);
1633         }
1634         if (err == -ENOENT && insert) {
1635                 if (item_size + extra_size >=
1636                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1637                         err = -EAGAIN;
1638                         goto out;
1639                 }
1640                 /*
1641                  * To add new inline back ref, we have to make sure
1642                  * there is no corresponding back ref item.
1643                  * For simplicity, we just do not add new inline back
1644                  * ref if there is any kind of item for this block
1645                  */
1646                 if (find_next_key(path, 0, &key) == 0 &&
1647                     key.objectid == bytenr &&
1648                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1649                         err = -EAGAIN;
1650                         goto out;
1651                 }
1652         }
1653         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1654 out:
1655         if (insert) {
1656                 path->keep_locks = 0;
1657                 btrfs_unlock_up_safe(path, 1);
1658         }
1659         return err;
1660 }
1661
1662 /*
1663  * helper to add new inline back ref
1664  */
1665 static noinline_for_stack
1666 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1667                                  struct btrfs_path *path,
1668                                  struct btrfs_extent_inline_ref *iref,
1669                                  u64 parent, u64 root_objectid,
1670                                  u64 owner, u64 offset, int refs_to_add,
1671                                  struct btrfs_delayed_extent_op *extent_op)
1672 {
1673         struct extent_buffer *leaf;
1674         struct btrfs_extent_item *ei;
1675         unsigned long ptr;
1676         unsigned long end;
1677         unsigned long item_offset;
1678         u64 refs;
1679         int size;
1680         int type;
1681
1682         leaf = path->nodes[0];
1683         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1684         item_offset = (unsigned long)iref - (unsigned long)ei;
1685
1686         type = extent_ref_type(parent, owner);
1687         size = btrfs_extent_inline_ref_size(type);
1688
1689         btrfs_extend_item(fs_info, path, size);
1690
1691         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1692         refs = btrfs_extent_refs(leaf, ei);
1693         refs += refs_to_add;
1694         btrfs_set_extent_refs(leaf, ei, refs);
1695         if (extent_op)
1696                 __run_delayed_extent_op(extent_op, leaf, ei);
1697
1698         ptr = (unsigned long)ei + item_offset;
1699         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1700         if (ptr < end - size)
1701                 memmove_extent_buffer(leaf, ptr + size, ptr,
1702                                       end - size - ptr);
1703
1704         iref = (struct btrfs_extent_inline_ref *)ptr;
1705         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1706         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1707                 struct btrfs_extent_data_ref *dref;
1708                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1709                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1710                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1711                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1712                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1713         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1714                 struct btrfs_shared_data_ref *sref;
1715                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1716                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1717                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1718         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1719                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1720         } else {
1721                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1722         }
1723         btrfs_mark_buffer_dirty(leaf);
1724 }
1725
1726 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1727                                  struct btrfs_path *path,
1728                                  struct btrfs_extent_inline_ref **ref_ret,
1729                                  u64 bytenr, u64 num_bytes, u64 parent,
1730                                  u64 root_objectid, u64 owner, u64 offset)
1731 {
1732         int ret;
1733
1734         ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
1735                                            num_bytes, parent, root_objectid,
1736                                            owner, offset, 0);
1737         if (ret != -ENOENT)
1738                 return ret;
1739
1740         btrfs_release_path(path);
1741         *ref_ret = NULL;
1742
1743         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1744                 ret = lookup_tree_block_ref(trans, path, bytenr, parent,
1745                                             root_objectid);
1746         } else {
1747                 ret = lookup_extent_data_ref(trans, path, bytenr, parent,
1748                                              root_objectid, owner, offset);
1749         }
1750         return ret;
1751 }
1752
1753 /*
1754  * helper to update/remove inline back ref
1755  */
1756 static noinline_for_stack
1757 void update_inline_extent_backref(struct btrfs_path *path,
1758                                   struct btrfs_extent_inline_ref *iref,
1759                                   int refs_to_mod,
1760                                   struct btrfs_delayed_extent_op *extent_op,
1761                                   int *last_ref)
1762 {
1763         struct extent_buffer *leaf = path->nodes[0];
1764         struct btrfs_fs_info *fs_info = leaf->fs_info;
1765         struct btrfs_extent_item *ei;
1766         struct btrfs_extent_data_ref *dref = NULL;
1767         struct btrfs_shared_data_ref *sref = NULL;
1768         unsigned long ptr;
1769         unsigned long end;
1770         u32 item_size;
1771         int size;
1772         int type;
1773         u64 refs;
1774
1775         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1776         refs = btrfs_extent_refs(leaf, ei);
1777         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1778         refs += refs_to_mod;
1779         btrfs_set_extent_refs(leaf, ei, refs);
1780         if (extent_op)
1781                 __run_delayed_extent_op(extent_op, leaf, ei);
1782
1783         /*
1784          * If type is invalid, we should have bailed out after
1785          * lookup_inline_extent_backref().
1786          */
1787         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1788         ASSERT(type != BTRFS_REF_TYPE_INVALID);
1789
1790         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1791                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1792                 refs = btrfs_extent_data_ref_count(leaf, dref);
1793         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1794                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1795                 refs = btrfs_shared_data_ref_count(leaf, sref);
1796         } else {
1797                 refs = 1;
1798                 BUG_ON(refs_to_mod != -1);
1799         }
1800
1801         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1802         refs += refs_to_mod;
1803
1804         if (refs > 0) {
1805                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1806                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1807                 else
1808                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1809         } else {
1810                 *last_ref = 1;
1811                 size =  btrfs_extent_inline_ref_size(type);
1812                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1813                 ptr = (unsigned long)iref;
1814                 end = (unsigned long)ei + item_size;
1815                 if (ptr + size < end)
1816                         memmove_extent_buffer(leaf, ptr, ptr + size,
1817                                               end - ptr - size);
1818                 item_size -= size;
1819                 btrfs_truncate_item(fs_info, path, item_size, 1);
1820         }
1821         btrfs_mark_buffer_dirty(leaf);
1822 }
1823
1824 static noinline_for_stack
1825 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1826                                  struct btrfs_path *path,
1827                                  u64 bytenr, u64 num_bytes, u64 parent,
1828                                  u64 root_objectid, u64 owner,
1829                                  u64 offset, int refs_to_add,
1830                                  struct btrfs_delayed_extent_op *extent_op)
1831 {
1832         struct btrfs_extent_inline_ref *iref;
1833         int ret;
1834
1835         ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
1836                                            num_bytes, parent, root_objectid,
1837                                            owner, offset, 1);
1838         if (ret == 0) {
1839                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1840                 update_inline_extent_backref(path, iref, refs_to_add,
1841                                              extent_op, NULL);
1842         } else if (ret == -ENOENT) {
1843                 setup_inline_extent_backref(trans->fs_info, path, iref, parent,
1844                                             root_objectid, owner, offset,
1845                                             refs_to_add, extent_op);
1846                 ret = 0;
1847         }
1848         return ret;
1849 }
1850
1851 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1852                                  struct btrfs_path *path,
1853                                  u64 bytenr, u64 parent, u64 root_objectid,
1854                                  u64 owner, u64 offset, int refs_to_add)
1855 {
1856         int ret;
1857         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1858                 BUG_ON(refs_to_add != 1);
1859                 ret = insert_tree_block_ref(trans, path, bytenr, parent,
1860                                             root_objectid);
1861         } else {
1862                 ret = insert_extent_data_ref(trans, path, bytenr, parent,
1863                                              root_objectid, owner, offset,
1864                                              refs_to_add);
1865         }
1866         return ret;
1867 }
1868
1869 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1870                                  struct btrfs_path *path,
1871                                  struct btrfs_extent_inline_ref *iref,
1872                                  int refs_to_drop, int is_data, int *last_ref)
1873 {
1874         int ret = 0;
1875
1876         BUG_ON(!is_data && refs_to_drop != 1);
1877         if (iref) {
1878                 update_inline_extent_backref(path, iref, -refs_to_drop, NULL,
1879                                              last_ref);
1880         } else if (is_data) {
1881                 ret = remove_extent_data_ref(trans, path, refs_to_drop,
1882                                              last_ref);
1883         } else {
1884                 *last_ref = 1;
1885                 ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
1886         }
1887         return ret;
1888 }
1889
1890 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1891 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1892                                u64 *discarded_bytes)
1893 {
1894         int j, ret = 0;
1895         u64 bytes_left, end;
1896         u64 aligned_start = ALIGN(start, 1 << 9);
1897
1898         if (WARN_ON(start != aligned_start)) {
1899                 len -= aligned_start - start;
1900                 len = round_down(len, 1 << 9);
1901                 start = aligned_start;
1902         }
1903
1904         *discarded_bytes = 0;
1905
1906         if (!len)
1907                 return 0;
1908
1909         end = start + len;
1910         bytes_left = len;
1911
1912         /* Skip any superblocks on this device. */
1913         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1914                 u64 sb_start = btrfs_sb_offset(j);
1915                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1916                 u64 size = sb_start - start;
1917
1918                 if (!in_range(sb_start, start, bytes_left) &&
1919                     !in_range(sb_end, start, bytes_left) &&
1920                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1921                         continue;
1922
1923                 /*
1924                  * Superblock spans beginning of range.  Adjust start and
1925                  * try again.
1926                  */
1927                 if (sb_start <= start) {
1928                         start += sb_end - start;
1929                         if (start > end) {
1930                                 bytes_left = 0;
1931                                 break;
1932                         }
1933                         bytes_left = end - start;
1934                         continue;
1935                 }
1936
1937                 if (size) {
1938                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
1939                                                    GFP_NOFS, 0);
1940                         if (!ret)
1941                                 *discarded_bytes += size;
1942                         else if (ret != -EOPNOTSUPP)
1943                                 return ret;
1944                 }
1945
1946                 start = sb_end;
1947                 if (start > end) {
1948                         bytes_left = 0;
1949                         break;
1950                 }
1951                 bytes_left = end - start;
1952         }
1953
1954         if (bytes_left) {
1955                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
1956                                            GFP_NOFS, 0);
1957                 if (!ret)
1958                         *discarded_bytes += bytes_left;
1959         }
1960         return ret;
1961 }
1962
1963 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
1964                          u64 num_bytes, u64 *actual_bytes)
1965 {
1966         int ret;
1967         u64 discarded_bytes = 0;
1968         struct btrfs_bio *bbio = NULL;
1969
1970
1971         /*
1972          * Avoid races with device replace and make sure our bbio has devices
1973          * associated to its stripes that don't go away while we are discarding.
1974          */
1975         btrfs_bio_counter_inc_blocked(fs_info);
1976         /* Tell the block device(s) that the sectors can be discarded */
1977         ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
1978                               &bbio, 0);
1979         /* Error condition is -ENOMEM */
1980         if (!ret) {
1981                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1982                 int i;
1983
1984
1985                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1986                         u64 bytes;
1987                         struct request_queue *req_q;
1988
1989                         if (!stripe->dev->bdev) {
1990                                 ASSERT(btrfs_test_opt(fs_info, DEGRADED));
1991                                 continue;
1992                         }
1993                         req_q = bdev_get_queue(stripe->dev->bdev);
1994                         if (!blk_queue_discard(req_q))
1995                                 continue;
1996
1997                         ret = btrfs_issue_discard(stripe->dev->bdev,
1998                                                   stripe->physical,
1999                                                   stripe->length,
2000                                                   &bytes);
2001                         if (!ret)
2002                                 discarded_bytes += bytes;
2003                         else if (ret != -EOPNOTSUPP)
2004                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2005
2006                         /*
2007                          * Just in case we get back EOPNOTSUPP for some reason,
2008                          * just ignore the return value so we don't screw up
2009                          * people calling discard_extent.
2010                          */
2011                         ret = 0;
2012                 }
2013                 btrfs_put_bbio(bbio);
2014         }
2015         btrfs_bio_counter_dec(fs_info);
2016
2017         if (actual_bytes)
2018                 *actual_bytes = discarded_bytes;
2019
2020
2021         if (ret == -EOPNOTSUPP)
2022                 ret = 0;
2023         return ret;
2024 }
2025
2026 /* Can return -ENOMEM */
2027 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2028                          struct btrfs_root *root,
2029                          u64 bytenr, u64 num_bytes, u64 parent,
2030                          u64 root_objectid, u64 owner, u64 offset)
2031 {
2032         struct btrfs_fs_info *fs_info = root->fs_info;
2033         int old_ref_mod, new_ref_mod;
2034         int ret;
2035
2036         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2037                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2038
2039         btrfs_ref_tree_mod(root, bytenr, num_bytes, parent, root_objectid,
2040                            owner, offset, BTRFS_ADD_DELAYED_REF);
2041
2042         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2043                 ret = btrfs_add_delayed_tree_ref(trans, bytenr,
2044                                                  num_bytes, parent,
2045                                                  root_objectid, (int)owner,
2046                                                  BTRFS_ADD_DELAYED_REF, NULL,
2047                                                  &old_ref_mod, &new_ref_mod);
2048         } else {
2049                 ret = btrfs_add_delayed_data_ref(trans, bytenr,
2050                                                  num_bytes, parent,
2051                                                  root_objectid, owner, offset,
2052                                                  0, BTRFS_ADD_DELAYED_REF,
2053                                                  &old_ref_mod, &new_ref_mod);
2054         }
2055
2056         if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0) {
2057                 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
2058
2059                 add_pinned_bytes(fs_info, -num_bytes, metadata, root_objectid);
2060         }
2061
2062         return ret;
2063 }
2064
2065 /*
2066  * __btrfs_inc_extent_ref - insert backreference for a given extent
2067  *
2068  * @trans:          Handle of transaction
2069  *
2070  * @node:           The delayed ref node used to get the bytenr/length for
2071  *                  extent whose references are incremented.
2072  *
2073  * @parent:         If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
2074  *                  BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
2075  *                  bytenr of the parent block. Since new extents are always
2076  *                  created with indirect references, this will only be the case
2077  *                  when relocating a shared extent. In that case, root_objectid
2078  *                  will be BTRFS_TREE_RELOC_OBJECTID. Otheriwse, parent must
2079  *                  be 0
2080  *
2081  * @root_objectid:  The id of the root where this modification has originated,
2082  *                  this can be either one of the well-known metadata trees or
2083  *                  the subvolume id which references this extent.
2084  *
2085  * @owner:          For data extents it is the inode number of the owning file.
2086  *                  For metadata extents this parameter holds the level in the
2087  *                  tree of the extent.
2088  *
2089  * @offset:         For metadata extents the offset is ignored and is currently
2090  *                  always passed as 0. For data extents it is the fileoffset
2091  *                  this extent belongs to.
2092  *
2093  * @refs_to_add     Number of references to add
2094  *
2095  * @extent_op       Pointer to a structure, holding information necessary when
2096  *                  updating a tree block's flags
2097  *
2098  */
2099 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2100                                   struct btrfs_delayed_ref_node *node,
2101                                   u64 parent, u64 root_objectid,
2102                                   u64 owner, u64 offset, int refs_to_add,
2103                                   struct btrfs_delayed_extent_op *extent_op)
2104 {
2105         struct btrfs_path *path;
2106         struct extent_buffer *leaf;
2107         struct btrfs_extent_item *item;
2108         struct btrfs_key key;
2109         u64 bytenr = node->bytenr;
2110         u64 num_bytes = node->num_bytes;
2111         u64 refs;
2112         int ret;
2113
2114         path = btrfs_alloc_path();
2115         if (!path)
2116                 return -ENOMEM;
2117
2118         path->reada = READA_FORWARD;
2119         path->leave_spinning = 1;
2120         /* this will setup the path even if it fails to insert the back ref */
2121         ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
2122                                            parent, root_objectid, owner,
2123                                            offset, refs_to_add, extent_op);
2124         if ((ret < 0 && ret != -EAGAIN) || !ret)
2125                 goto out;
2126
2127         /*
2128          * Ok we had -EAGAIN which means we didn't have space to insert and
2129          * inline extent ref, so just update the reference count and add a
2130          * normal backref.
2131          */
2132         leaf = path->nodes[0];
2133         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2134         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2135         refs = btrfs_extent_refs(leaf, item);
2136         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2137         if (extent_op)
2138                 __run_delayed_extent_op(extent_op, leaf, item);
2139
2140         btrfs_mark_buffer_dirty(leaf);
2141         btrfs_release_path(path);
2142
2143         path->reada = READA_FORWARD;
2144         path->leave_spinning = 1;
2145         /* now insert the actual backref */
2146         ret = insert_extent_backref(trans, path, bytenr, parent, root_objectid,
2147                                     owner, offset, refs_to_add);
2148         if (ret)
2149                 btrfs_abort_transaction(trans, ret);
2150 out:
2151         btrfs_free_path(path);
2152         return ret;
2153 }
2154
2155 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2156                                 struct btrfs_delayed_ref_node *node,
2157                                 struct btrfs_delayed_extent_op *extent_op,
2158                                 int insert_reserved)
2159 {
2160         int ret = 0;
2161         struct btrfs_delayed_data_ref *ref;
2162         struct btrfs_key ins;
2163         u64 parent = 0;
2164         u64 ref_root = 0;
2165         u64 flags = 0;
2166
2167         ins.objectid = node->bytenr;
2168         ins.offset = node->num_bytes;
2169         ins.type = BTRFS_EXTENT_ITEM_KEY;
2170
2171         ref = btrfs_delayed_node_to_data_ref(node);
2172         trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
2173
2174         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2175                 parent = ref->parent;
2176         ref_root = ref->root;
2177
2178         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2179                 if (extent_op)
2180                         flags |= extent_op->flags_to_set;
2181                 ret = alloc_reserved_file_extent(trans, parent, ref_root,
2182                                                  flags, ref->objectid,
2183                                                  ref->offset, &ins,
2184                                                  node->ref_mod);
2185         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2186                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
2187                                              ref->objectid, ref->offset,
2188                                              node->ref_mod, extent_op);
2189         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2190                 ret = __btrfs_free_extent(trans, node, parent,
2191                                           ref_root, ref->objectid,
2192                                           ref->offset, node->ref_mod,
2193                                           extent_op);
2194         } else {
2195                 BUG();
2196         }
2197         return ret;
2198 }
2199
2200 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2201                                     struct extent_buffer *leaf,
2202                                     struct btrfs_extent_item *ei)
2203 {
2204         u64 flags = btrfs_extent_flags(leaf, ei);
2205         if (extent_op->update_flags) {
2206                 flags |= extent_op->flags_to_set;
2207                 btrfs_set_extent_flags(leaf, ei, flags);
2208         }
2209
2210         if (extent_op->update_key) {
2211                 struct btrfs_tree_block_info *bi;
2212                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2213                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2214                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2215         }
2216 }
2217
2218 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2219                                  struct btrfs_delayed_ref_head *head,
2220                                  struct btrfs_delayed_extent_op *extent_op)
2221 {
2222         struct btrfs_fs_info *fs_info = trans->fs_info;
2223         struct btrfs_key key;
2224         struct btrfs_path *path;
2225         struct btrfs_extent_item *ei;
2226         struct extent_buffer *leaf;
2227         u32 item_size;
2228         int ret;
2229         int err = 0;
2230         int metadata = !extent_op->is_data;
2231
2232         if (trans->aborted)
2233                 return 0;
2234
2235         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2236                 metadata = 0;
2237
2238         path = btrfs_alloc_path();
2239         if (!path)
2240                 return -ENOMEM;
2241
2242         key.objectid = head->bytenr;
2243
2244         if (metadata) {
2245                 key.type = BTRFS_METADATA_ITEM_KEY;
2246                 key.offset = extent_op->level;
2247         } else {
2248                 key.type = BTRFS_EXTENT_ITEM_KEY;
2249                 key.offset = head->num_bytes;
2250         }
2251
2252 again:
2253         path->reada = READA_FORWARD;
2254         path->leave_spinning = 1;
2255         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
2256         if (ret < 0) {
2257                 err = ret;
2258                 goto out;
2259         }
2260         if (ret > 0) {
2261                 if (metadata) {
2262                         if (path->slots[0] > 0) {
2263                                 path->slots[0]--;
2264                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2265                                                       path->slots[0]);
2266                                 if (key.objectid == head->bytenr &&
2267                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2268                                     key.offset == head->num_bytes)
2269                                         ret = 0;
2270                         }
2271                         if (ret > 0) {
2272                                 btrfs_release_path(path);
2273                                 metadata = 0;
2274
2275                                 key.objectid = head->bytenr;
2276                                 key.offset = head->num_bytes;
2277                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2278                                 goto again;
2279                         }
2280                 } else {
2281                         err = -EIO;
2282                         goto out;
2283                 }
2284         }
2285
2286         leaf = path->nodes[0];
2287         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2288
2289         if (unlikely(item_size < sizeof(*ei))) {
2290                 err = -EINVAL;
2291                 btrfs_print_v0_err(fs_info);
2292                 btrfs_abort_transaction(trans, err);
2293                 goto out;
2294         }
2295
2296         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2297         __run_delayed_extent_op(extent_op, leaf, ei);
2298
2299         btrfs_mark_buffer_dirty(leaf);
2300 out:
2301         btrfs_free_path(path);
2302         return err;
2303 }
2304
2305 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2306                                 struct btrfs_delayed_ref_node *node,
2307                                 struct btrfs_delayed_extent_op *extent_op,
2308                                 int insert_reserved)
2309 {
2310         int ret = 0;
2311         struct btrfs_delayed_tree_ref *ref;
2312         u64 parent = 0;
2313         u64 ref_root = 0;
2314
2315         ref = btrfs_delayed_node_to_tree_ref(node);
2316         trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
2317
2318         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2319                 parent = ref->parent;
2320         ref_root = ref->root;
2321
2322         if (node->ref_mod != 1) {
2323                 btrfs_err(trans->fs_info,
2324         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2325                           node->bytenr, node->ref_mod, node->action, ref_root,
2326                           parent);
2327                 return -EIO;
2328         }
2329         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2330                 BUG_ON(!extent_op || !extent_op->update_flags);
2331                 ret = alloc_reserved_tree_block(trans, node, extent_op);
2332         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2333                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
2334                                              ref->level, 0, 1, extent_op);
2335         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2336                 ret = __btrfs_free_extent(trans, node, parent, ref_root,
2337                                           ref->level, 0, 1, extent_op);
2338         } else {
2339                 BUG();
2340         }
2341         return ret;
2342 }
2343
2344 /* helper function to actually process a single delayed ref entry */
2345 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2346                                struct btrfs_delayed_ref_node *node,
2347                                struct btrfs_delayed_extent_op *extent_op,
2348                                int insert_reserved)
2349 {
2350         int ret = 0;
2351
2352         if (trans->aborted) {
2353                 if (insert_reserved)
2354                         btrfs_pin_extent(trans->fs_info, node->bytenr,
2355                                          node->num_bytes, 1);
2356                 return 0;
2357         }
2358
2359         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2360             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2361                 ret = run_delayed_tree_ref(trans, node, extent_op,
2362                                            insert_reserved);
2363         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2364                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2365                 ret = run_delayed_data_ref(trans, node, extent_op,
2366                                            insert_reserved);
2367         else
2368                 BUG();
2369         if (ret && insert_reserved)
2370                 btrfs_pin_extent(trans->fs_info, node->bytenr,
2371                                  node->num_bytes, 1);
2372         return ret;
2373 }
2374
2375 static inline struct btrfs_delayed_ref_node *
2376 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2377 {
2378         struct btrfs_delayed_ref_node *ref;
2379
2380         if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
2381                 return NULL;
2382
2383         /*
2384          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2385          * This is to prevent a ref count from going down to zero, which deletes
2386          * the extent item from the extent tree, when there still are references
2387          * to add, which would fail because they would not find the extent item.
2388          */
2389         if (!list_empty(&head->ref_add_list))
2390                 return list_first_entry(&head->ref_add_list,
2391                                 struct btrfs_delayed_ref_node, add_list);
2392
2393         ref = rb_entry(rb_first_cached(&head->ref_tree),
2394                        struct btrfs_delayed_ref_node, ref_node);
2395         ASSERT(list_empty(&ref->add_list));
2396         return ref;
2397 }
2398
2399 static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
2400                                       struct btrfs_delayed_ref_head *head)
2401 {
2402         spin_lock(&delayed_refs->lock);
2403         head->processing = 0;
2404         delayed_refs->num_heads_ready++;
2405         spin_unlock(&delayed_refs->lock);
2406         btrfs_delayed_ref_unlock(head);
2407 }
2408
2409 static int cleanup_extent_op(struct btrfs_trans_handle *trans,
2410                              struct btrfs_delayed_ref_head *head)
2411 {
2412         struct btrfs_delayed_extent_op *extent_op = head->extent_op;
2413         int ret;
2414
2415         if (!extent_op)
2416                 return 0;
2417         head->extent_op = NULL;
2418         if (head->must_insert_reserved) {
2419                 btrfs_free_delayed_extent_op(extent_op);
2420                 return 0;
2421         }
2422         spin_unlock(&head->lock);
2423         ret = run_delayed_extent_op(trans, head, extent_op);
2424         btrfs_free_delayed_extent_op(extent_op);
2425         return ret ? ret : 1;
2426 }
2427
2428 static int cleanup_ref_head(struct btrfs_trans_handle *trans,
2429                             struct btrfs_delayed_ref_head *head)
2430 {
2431
2432         struct btrfs_fs_info *fs_info = trans->fs_info;
2433         struct btrfs_delayed_ref_root *delayed_refs;
2434         int ret;
2435
2436         delayed_refs = &trans->transaction->delayed_refs;
2437
2438         ret = cleanup_extent_op(trans, head);
2439         if (ret < 0) {
2440                 unselect_delayed_ref_head(delayed_refs, head);
2441                 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2442                 return ret;
2443         } else if (ret) {
2444                 return ret;
2445         }
2446
2447         /*
2448          * Need to drop our head ref lock and re-acquire the delayed ref lock
2449          * and then re-check to make sure nobody got added.
2450          */
2451         spin_unlock(&head->lock);
2452         spin_lock(&delayed_refs->lock);
2453         spin_lock(&head->lock);
2454         if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
2455                 spin_unlock(&head->lock);
2456                 spin_unlock(&delayed_refs->lock);
2457                 return 1;
2458         }
2459         delayed_refs->num_heads--;
2460         rb_erase_cached(&head->href_node, &delayed_refs->href_root);
2461         RB_CLEAR_NODE(&head->href_node);
2462         spin_unlock(&head->lock);
2463         spin_unlock(&delayed_refs->lock);
2464         atomic_dec(&delayed_refs->num_entries);
2465
2466         trace_run_delayed_ref_head(fs_info, head, 0);
2467
2468         if (head->total_ref_mod < 0) {
2469                 struct btrfs_space_info *space_info;
2470                 u64 flags;
2471
2472                 if (head->is_data)
2473                         flags = BTRFS_BLOCK_GROUP_DATA;
2474                 else if (head->is_system)
2475                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
2476                 else
2477                         flags = BTRFS_BLOCK_GROUP_METADATA;
2478                 space_info = __find_space_info(fs_info, flags);
2479                 ASSERT(space_info);
2480                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
2481                                    -head->num_bytes,
2482                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
2483
2484                 if (head->is_data) {
2485                         spin_lock(&delayed_refs->lock);
2486                         delayed_refs->pending_csums -= head->num_bytes;
2487                         spin_unlock(&delayed_refs->lock);
2488                 }
2489         }
2490
2491         if (head->must_insert_reserved) {
2492                 btrfs_pin_extent(fs_info, head->bytenr,
2493                                  head->num_bytes, 1);
2494                 if (head->is_data) {
2495                         ret = btrfs_del_csums(trans, fs_info, head->bytenr,
2496                                               head->num_bytes);
2497                 }
2498         }
2499
2500         /* Also free its reserved qgroup space */
2501         btrfs_qgroup_free_delayed_ref(fs_info, head->qgroup_ref_root,
2502                                       head->qgroup_reserved);
2503         btrfs_delayed_ref_unlock(head);
2504         btrfs_put_delayed_ref_head(head);
2505         return 0;
2506 }
2507
2508 static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
2509                                         struct btrfs_trans_handle *trans)
2510 {
2511         struct btrfs_delayed_ref_root *delayed_refs =
2512                 &trans->transaction->delayed_refs;
2513         struct btrfs_delayed_ref_head *head = NULL;
2514         int ret;
2515
2516         spin_lock(&delayed_refs->lock);
2517         head = btrfs_select_ref_head(delayed_refs);
2518         if (!head) {
2519                 spin_unlock(&delayed_refs->lock);
2520                 return head;
2521         }
2522
2523         /*
2524          * Grab the lock that says we are going to process all the refs for
2525          * this head
2526          */
2527         ret = btrfs_delayed_ref_lock(delayed_refs, head);
2528         spin_unlock(&delayed_refs->lock);
2529
2530         /*
2531          * We may have dropped the spin lock to get the head mutex lock, and
2532          * that might have given someone else time to free the head.  If that's
2533          * true, it has been removed from our list and we can move on.
2534          */
2535         if (ret == -EAGAIN)
2536                 head = ERR_PTR(-EAGAIN);
2537
2538         return head;
2539 }
2540
2541 static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
2542                                     struct btrfs_delayed_ref_head *locked_ref,
2543                                     unsigned long *run_refs)
2544 {
2545         struct btrfs_fs_info *fs_info = trans->fs_info;
2546         struct btrfs_delayed_ref_root *delayed_refs;
2547         struct btrfs_delayed_extent_op *extent_op;
2548         struct btrfs_delayed_ref_node *ref;
2549         int must_insert_reserved = 0;
2550         int ret;
2551
2552         delayed_refs = &trans->transaction->delayed_refs;
2553
2554         lockdep_assert_held(&locked_ref->mutex);
2555         lockdep_assert_held(&locked_ref->lock);
2556
2557         while ((ref = select_delayed_ref(locked_ref))) {
2558                 if (ref->seq &&
2559                     btrfs_check_delayed_seq(fs_info, ref->seq)) {
2560                         spin_unlock(&locked_ref->lock);
2561                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2562                         return -EAGAIN;
2563                 }
2564
2565                 (*run_refs)++;
2566                 ref->in_tree = 0;
2567                 rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
2568                 RB_CLEAR_NODE(&ref->ref_node);
2569                 if (!list_empty(&ref->add_list))
2570                         list_del(&ref->add_list);
2571                 /*
2572                  * When we play the delayed ref, also correct the ref_mod on
2573                  * head
2574                  */
2575                 switch (ref->action) {
2576                 case BTRFS_ADD_DELAYED_REF:
2577                 case BTRFS_ADD_DELAYED_EXTENT:
2578                         locked_ref->ref_mod -= ref->ref_mod;
2579                         break;
2580                 case BTRFS_DROP_DELAYED_REF:
2581                         locked_ref->ref_mod += ref->ref_mod;
2582                         break;
2583                 default:
2584                         WARN_ON(1);
2585                 }
2586                 atomic_dec(&delayed_refs->num_entries);
2587
2588                 /*
2589                  * Record the must_insert_reserved flag before we drop the
2590                  * spin lock.
2591                  */
2592                 must_insert_reserved = locked_ref->must_insert_reserved;
2593                 locked_ref->must_insert_reserved = 0;
2594
2595                 extent_op = locked_ref->extent_op;
2596                 locked_ref->extent_op = NULL;
2597                 spin_unlock(&locked_ref->lock);
2598
2599                 ret = run_one_delayed_ref(trans, ref, extent_op,
2600                                           must_insert_reserved);
2601
2602                 btrfs_free_delayed_extent_op(extent_op);
2603                 if (ret) {
2604                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2605                         btrfs_put_delayed_ref(ref);
2606                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2607                                     ret);
2608                         return ret;
2609                 }
2610
2611                 btrfs_put_delayed_ref(ref);
2612                 cond_resched();
2613
2614                 spin_lock(&locked_ref->lock);
2615                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2616         }
2617
2618         return 0;
2619 }
2620
2621 /*
2622  * Returns 0 on success or if called with an already aborted transaction.
2623  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2624  */
2625 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2626                                              unsigned long nr)
2627 {
2628         struct btrfs_fs_info *fs_info = trans->fs_info;
2629         struct btrfs_delayed_ref_root *delayed_refs;
2630         struct btrfs_delayed_ref_head *locked_ref = NULL;
2631         ktime_t start = ktime_get();
2632         int ret;
2633         unsigned long count = 0;
2634         unsigned long actual_count = 0;
2635
2636         delayed_refs = &trans->transaction->delayed_refs;
2637         do {
2638                 if (!locked_ref) {
2639                         locked_ref = btrfs_obtain_ref_head(trans);
2640                         if (IS_ERR_OR_NULL(locked_ref)) {
2641                                 if (PTR_ERR(locked_ref) == -EAGAIN) {
2642                                         continue;
2643                                 } else {
2644                                         break;
2645                                 }
2646                         }
2647                         count++;
2648                 }
2649                 /*
2650                  * We need to try and merge add/drops of the same ref since we
2651                  * can run into issues with relocate dropping the implicit ref
2652                  * and then it being added back again before the drop can
2653                  * finish.  If we merged anything we need to re-loop so we can
2654                  * get a good ref.
2655                  * Or we can get node references of the same type that weren't
2656                  * merged when created due to bumps in the tree mod seq, and
2657                  * we need to merge them to prevent adding an inline extent
2658                  * backref before dropping it (triggering a BUG_ON at
2659                  * insert_inline_extent_backref()).
2660                  */
2661                 spin_lock(&locked_ref->lock);
2662                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2663
2664                 ret = btrfs_run_delayed_refs_for_head(trans, locked_ref,
2665                                                       &actual_count);
2666                 if (ret < 0 && ret != -EAGAIN) {
2667                         /*
2668                          * Error, btrfs_run_delayed_refs_for_head already
2669                          * unlocked everything so just bail out
2670                          */
2671                         return ret;
2672                 } else if (!ret) {
2673                         /*
2674                          * Success, perform the usual cleanup of a processed
2675                          * head
2676                          */
2677                         ret = cleanup_ref_head(trans, locked_ref);
2678                         if (ret > 0 ) {
2679                                 /* We dropped our lock, we need to loop. */
2680                                 ret = 0;
2681                                 continue;
2682                         } else if (ret) {
2683                                 return ret;
2684                         }
2685                 }
2686
2687                 /*
2688                  * Either success case or btrfs_run_delayed_refs_for_head
2689                  * returned -EAGAIN, meaning we need to select another head
2690                  */
2691
2692                 locked_ref = NULL;
2693                 cond_resched();
2694         } while ((nr != -1 && count < nr) || locked_ref);
2695
2696         /*
2697          * We don't want to include ref heads since we can have empty ref heads
2698          * and those will drastically skew our runtime down since we just do
2699          * accounting, no actual extent tree updates.
2700          */
2701         if (actual_count > 0) {
2702                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2703                 u64 avg;
2704
2705                 /*
2706                  * We weigh the current average higher than our current runtime
2707                  * to avoid large swings in the average.
2708                  */
2709                 spin_lock(&delayed_refs->lock);
2710                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2711                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2712                 spin_unlock(&delayed_refs->lock);
2713         }
2714         return 0;
2715 }
2716
2717 #ifdef SCRAMBLE_DELAYED_REFS
2718 /*
2719  * Normally delayed refs get processed in ascending bytenr order. This
2720  * correlates in most cases to the order added. To expose dependencies on this
2721  * order, we start to process the tree in the middle instead of the beginning
2722  */
2723 static u64 find_middle(struct rb_root *root)
2724 {
2725         struct rb_node *n = root->rb_node;
2726         struct btrfs_delayed_ref_node *entry;
2727         int alt = 1;
2728         u64 middle;
2729         u64 first = 0, last = 0;
2730
2731         n = rb_first(root);
2732         if (n) {
2733                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2734                 first = entry->bytenr;
2735         }
2736         n = rb_last(root);
2737         if (n) {
2738                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2739                 last = entry->bytenr;
2740         }
2741         n = root->rb_node;
2742
2743         while (n) {
2744                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2745                 WARN_ON(!entry->in_tree);
2746
2747                 middle = entry->bytenr;
2748
2749                 if (alt)
2750                         n = n->rb_left;
2751                 else
2752                         n = n->rb_right;
2753
2754                 alt = 1 - alt;
2755         }
2756         return middle;
2757 }
2758 #endif
2759
2760 static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2761 {
2762         u64 num_bytes;
2763
2764         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2765                              sizeof(struct btrfs_extent_inline_ref));
2766         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2767                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2768
2769         /*
2770          * We don't ever fill up leaves all the way so multiply by 2 just to be
2771          * closer to what we're really going to want to use.
2772          */
2773         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2774 }
2775
2776 /*
2777  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2778  * would require to store the csums for that many bytes.
2779  */
2780 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2781 {
2782         u64 csum_size;
2783         u64 num_csums_per_leaf;
2784         u64 num_csums;
2785
2786         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2787         num_csums_per_leaf = div64_u64(csum_size,
2788                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2789         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2790         num_csums += num_csums_per_leaf - 1;
2791         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2792         return num_csums;
2793 }
2794
2795 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans)
2796 {
2797         struct btrfs_fs_info *fs_info = trans->fs_info;
2798         struct btrfs_block_rsv *global_rsv;
2799         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2800         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2801         unsigned int num_dirty_bgs = trans->transaction->num_dirty_bgs;
2802         u64 num_bytes, num_dirty_bgs_bytes;
2803         int ret = 0;
2804
2805         num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
2806         num_heads = heads_to_leaves(fs_info, num_heads);
2807         if (num_heads > 1)
2808                 num_bytes += (num_heads - 1) * fs_info->nodesize;
2809         num_bytes <<= 1;
2810         num_bytes += btrfs_csum_bytes_to_leaves(fs_info, csum_bytes) *
2811                                                         fs_info->nodesize;
2812         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(fs_info,
2813                                                              num_dirty_bgs);
2814         global_rsv = &fs_info->global_block_rsv;
2815
2816         /*
2817          * If we can't allocate any more chunks lets make sure we have _lots_ of
2818          * wiggle room since running delayed refs can create more delayed refs.
2819          */
2820         if (global_rsv->space_info->full) {
2821                 num_dirty_bgs_bytes <<= 1;
2822                 num_bytes <<= 1;
2823         }
2824
2825         spin_lock(&global_rsv->lock);
2826         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2827                 ret = 1;
2828         spin_unlock(&global_rsv->lock);
2829         return ret;
2830 }
2831
2832 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans)
2833 {
2834         u64 num_entries =
2835                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2836         u64 avg_runtime;
2837         u64 val;
2838
2839         smp_mb();
2840         avg_runtime = trans->fs_info->avg_delayed_ref_runtime;
2841         val = num_entries * avg_runtime;
2842         if (val >= NSEC_PER_SEC)
2843                 return 1;
2844         if (val >= NSEC_PER_SEC / 2)
2845                 return 2;
2846
2847         return btrfs_check_space_for_delayed_refs(trans);
2848 }
2849
2850 struct async_delayed_refs {
2851         struct btrfs_root *root;
2852         u64 transid;
2853         int count;
2854         int error;
2855         int sync;
2856         struct completion wait;
2857         struct btrfs_work work;
2858 };
2859
2860 static inline struct async_delayed_refs *
2861 to_async_delayed_refs(struct btrfs_work *work)
2862 {
2863         return container_of(work, struct async_delayed_refs, work);
2864 }
2865
2866 static void delayed_ref_async_start(struct btrfs_work *work)
2867 {
2868         struct async_delayed_refs *async = to_async_delayed_refs(work);
2869         struct btrfs_trans_handle *trans;
2870         struct btrfs_fs_info *fs_info = async->root->fs_info;
2871         int ret;
2872
2873         /* if the commit is already started, we don't need to wait here */
2874         if (btrfs_transaction_blocked(fs_info))
2875                 goto done;
2876
2877         trans = btrfs_join_transaction(async->root);
2878         if (IS_ERR(trans)) {
2879                 async->error = PTR_ERR(trans);
2880                 goto done;
2881         }
2882
2883         /*
2884          * trans->sync means that when we call end_transaction, we won't
2885          * wait on delayed refs
2886          */
2887         trans->sync = true;
2888
2889         /* Don't bother flushing if we got into a different transaction */
2890         if (trans->transid > async->transid)
2891                 goto end;
2892
2893         ret = btrfs_run_delayed_refs(trans, async->count);
2894         if (ret)
2895                 async->error = ret;
2896 end:
2897         ret = btrfs_end_transaction(trans);
2898         if (ret && !async->error)
2899                 async->error = ret;
2900 done:
2901         if (async->sync)
2902                 complete(&async->wait);
2903         else
2904                 kfree(async);
2905 }
2906
2907 int btrfs_async_run_delayed_refs(struct btrfs_fs_info *fs_info,
2908                                  unsigned long count, u64 transid, int wait)
2909 {
2910         struct async_delayed_refs *async;
2911         int ret;
2912
2913         async = kmalloc(sizeof(*async), GFP_NOFS);
2914         if (!async)
2915                 return -ENOMEM;
2916
2917         async->root = fs_info->tree_root;
2918         async->count = count;
2919         async->error = 0;
2920         async->transid = transid;
2921         if (wait)
2922                 async->sync = 1;
2923         else
2924                 async->sync = 0;
2925         init_completion(&async->wait);
2926
2927         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2928                         delayed_ref_async_start, NULL, NULL);
2929
2930         btrfs_queue_work(fs_info->extent_workers, &async->work);
2931
2932         if (wait) {
2933                 wait_for_completion(&async->wait);
2934                 ret = async->error;
2935                 kfree(async);
2936                 return ret;
2937         }
2938         return 0;
2939 }
2940
2941 /*
2942  * this starts processing the delayed reference count updates and
2943  * extent insertions we have queued up so far.  count can be
2944  * 0, which means to process everything in the tree at the start
2945  * of the run (but not newly added entries), or it can be some target
2946  * number you'd like to process.
2947  *
2948  * Returns 0 on success or if called with an aborted transaction
2949  * Returns <0 on error and aborts the transaction
2950  */
2951 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2952                            unsigned long count)
2953 {
2954         struct btrfs_fs_info *fs_info = trans->fs_info;
2955         struct rb_node *node;
2956         struct btrfs_delayed_ref_root *delayed_refs;
2957         struct btrfs_delayed_ref_head *head;
2958         int ret;
2959         int run_all = count == (unsigned long)-1;
2960
2961         /* We'll clean this up in btrfs_cleanup_transaction */
2962         if (trans->aborted)
2963                 return 0;
2964
2965         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2966                 return 0;
2967
2968         delayed_refs = &trans->transaction->delayed_refs;
2969         if (count == 0)
2970                 count = atomic_read(&delayed_refs->num_entries) * 2;
2971
2972 again:
2973 #ifdef SCRAMBLE_DELAYED_REFS
2974         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2975 #endif
2976         ret = __btrfs_run_delayed_refs(trans, count);
2977         if (ret < 0) {
2978                 btrfs_abort_transaction(trans, ret);
2979                 return ret;
2980         }
2981
2982         if (run_all) {
2983                 if (!list_empty(&trans->new_bgs))
2984                         btrfs_create_pending_block_groups(trans);
2985
2986                 spin_lock(&delayed_refs->lock);
2987                 node = rb_first_cached(&delayed_refs->href_root);
2988                 if (!node) {
2989                         spin_unlock(&delayed_refs->lock);
2990                         goto out;
2991                 }
2992                 head = rb_entry(node, struct btrfs_delayed_ref_head,
2993                                 href_node);
2994                 refcount_inc(&head->refs);
2995                 spin_unlock(&delayed_refs->lock);
2996
2997                 /* Mutex was contended, block until it's released and retry. */
2998                 mutex_lock(&head->mutex);
2999                 mutex_unlock(&head->mutex);
3000
3001                 btrfs_put_delayed_ref_head(head);
3002                 cond_resched();
3003                 goto again;
3004         }
3005 out:
3006         return 0;
3007 }
3008
3009 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3010                                 struct btrfs_fs_info *fs_info,
3011                                 u64 bytenr, u64 num_bytes, u64 flags,
3012                                 int level, int is_data)
3013 {
3014         struct btrfs_delayed_extent_op *extent_op;
3015         int ret;
3016
3017         extent_op = btrfs_alloc_delayed_extent_op();
3018         if (!extent_op)
3019                 return -ENOMEM;
3020
3021         extent_op->flags_to_set = flags;
3022         extent_op->update_flags = true;
3023         extent_op->update_key = false;
3024         extent_op->is_data = is_data ? true : false;
3025         extent_op->level = level;
3026
3027         ret = btrfs_add_delayed_extent_op(fs_info, trans, bytenr,
3028                                           num_bytes, extent_op);
3029         if (ret)
3030                 btrfs_free_delayed_extent_op(extent_op);
3031         return ret;
3032 }
3033
3034 static noinline int check_delayed_ref(struct btrfs_root *root,
3035                                       struct btrfs_path *path,
3036                                       u64 objectid, u64 offset, u64 bytenr)
3037 {
3038         struct btrfs_delayed_ref_head *head;
3039         struct btrfs_delayed_ref_node *ref;
3040         struct btrfs_delayed_data_ref *data_ref;
3041         struct btrfs_delayed_ref_root *delayed_refs;
3042         struct btrfs_transaction *cur_trans;
3043         struct rb_node *node;
3044         int ret = 0;
3045
3046         spin_lock(&root->fs_info->trans_lock);
3047         cur_trans = root->fs_info->running_transaction;
3048         if (cur_trans)
3049                 refcount_inc(&cur_trans->use_count);
3050         spin_unlock(&root->fs_info->trans_lock);
3051         if (!cur_trans)
3052                 return 0;
3053
3054         delayed_refs = &cur_trans->delayed_refs;
3055         spin_lock(&delayed_refs->lock);
3056         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3057         if (!head) {
3058                 spin_unlock(&delayed_refs->lock);
3059                 btrfs_put_transaction(cur_trans);
3060                 return 0;
3061         }
3062
3063         if (!mutex_trylock(&head->mutex)) {
3064                 refcount_inc(&head->refs);
3065                 spin_unlock(&delayed_refs->lock);
3066
3067                 btrfs_release_path(path);
3068
3069                 /*
3070                  * Mutex was contended, block until it's released and let
3071                  * caller try again
3072                  */
3073                 mutex_lock(&head->mutex);
3074                 mutex_unlock(&head->mutex);
3075                 btrfs_put_delayed_ref_head(head);
3076                 btrfs_put_transaction(cur_trans);
3077                 return -EAGAIN;
3078         }
3079         spin_unlock(&delayed_refs->lock);
3080
3081         spin_lock(&head->lock);
3082         /*
3083          * XXX: We should replace this with a proper search function in the
3084          * future.
3085          */
3086         for (node = rb_first_cached(&head->ref_tree); node;
3087              node = rb_next(node)) {
3088                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
3089                 /* If it's a shared ref we know a cross reference exists */
3090                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3091                         ret = 1;
3092                         break;
3093                 }
3094
3095                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3096
3097                 /*
3098                  * If our ref doesn't match the one we're currently looking at
3099                  * then we have a cross reference.
3100                  */
3101                 if (data_ref->root != root->root_key.objectid ||
3102                     data_ref->objectid != objectid ||
3103                     data_ref->offset != offset) {
3104                         ret = 1;
3105                         break;
3106                 }
3107         }
3108         spin_unlock(&head->lock);
3109         mutex_unlock(&head->mutex);
3110         btrfs_put_transaction(cur_trans);
3111         return ret;
3112 }
3113
3114 static noinline int check_committed_ref(struct btrfs_root *root,
3115                                         struct btrfs_path *path,
3116                                         u64 objectid, u64 offset, u64 bytenr)
3117 {
3118         struct btrfs_fs_info *fs_info = root->fs_info;
3119         struct btrfs_root *extent_root = fs_info->extent_root;
3120         struct extent_buffer *leaf;
3121         struct btrfs_extent_data_ref *ref;
3122         struct btrfs_extent_inline_ref *iref;
3123         struct btrfs_extent_item *ei;
3124         struct btrfs_key key;
3125         u32 item_size;
3126         int type;
3127         int ret;
3128
3129         key.objectid = bytenr;
3130         key.offset = (u64)-1;
3131         key.type = BTRFS_EXTENT_ITEM_KEY;
3132
3133         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3134         if (ret < 0)
3135                 goto out;
3136         BUG_ON(ret == 0); /* Corruption */
3137
3138         ret = -ENOENT;
3139         if (path->slots[0] == 0)
3140                 goto out;
3141
3142         path->slots[0]--;
3143         leaf = path->nodes[0];
3144         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3145
3146         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3147                 goto out;
3148
3149         ret = 1;
3150         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3151         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3152
3153         if (item_size != sizeof(*ei) +
3154             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3155                 goto out;
3156
3157         if (btrfs_extent_generation(leaf, ei) <=
3158             btrfs_root_last_snapshot(&root->root_item))
3159                 goto out;
3160
3161         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3162
3163         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
3164         if (type != BTRFS_EXTENT_DATA_REF_KEY)
3165                 goto out;
3166
3167         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3168         if (btrfs_extent_refs(leaf, ei) !=
3169             btrfs_extent_data_ref_count(leaf, ref) ||
3170             btrfs_extent_data_ref_root(leaf, ref) !=
3171             root->root_key.objectid ||
3172             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3173             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3174                 goto out;
3175
3176         ret = 0;
3177 out:
3178         return ret;
3179 }
3180
3181 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
3182                           u64 bytenr)
3183 {
3184         struct btrfs_path *path;
3185         int ret;
3186
3187         path = btrfs_alloc_path();
3188         if (!path)
3189                 return -ENOMEM;
3190
3191         do {
3192                 ret = check_committed_ref(root, path, objectid,
3193                                           offset, bytenr);
3194                 if (ret && ret != -ENOENT)
3195                         goto out;
3196
3197                 ret = check_delayed_ref(root, path, objectid, offset, bytenr);
3198         } while (ret == -EAGAIN);
3199
3200 out:
3201         btrfs_free_path(path);
3202         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3203                 WARN_ON(ret > 0);
3204         return ret;
3205 }
3206
3207 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3208                            struct btrfs_root *root,
3209                            struct extent_buffer *buf,
3210                            int full_backref, int inc)
3211 {
3212         struct btrfs_fs_info *fs_info = root->fs_info;
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 *,
3224                             struct btrfs_root *,
3225                             u64, u64, u64, u64, u64, u64);
3226
3227
3228         if (btrfs_is_testing(fs_info))
3229                 return 0;
3230
3231         ref_root = btrfs_header_owner(buf);
3232         nritems = btrfs_header_nritems(buf);
3233         level = btrfs_header_level(buf);
3234
3235         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3236                 return 0;
3237
3238         if (inc)
3239                 process_func = btrfs_inc_extent_ref;
3240         else
3241                 process_func = btrfs_free_extent;
3242
3243         if (full_backref)
3244                 parent = buf->start;
3245         else
3246                 parent = 0;
3247
3248         for (i = 0; i < nritems; i++) {
3249                 if (level == 0) {
3250                         btrfs_item_key_to_cpu(buf, &key, i);
3251                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3252                                 continue;
3253                         fi = btrfs_item_ptr(buf, i,
3254                                             struct btrfs_file_extent_item);
3255                         if (btrfs_file_extent_type(buf, fi) ==
3256                             BTRFS_FILE_EXTENT_INLINE)
3257                                 continue;
3258                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3259                         if (bytenr == 0)
3260                                 continue;
3261
3262                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3263                         key.offset -= btrfs_file_extent_offset(buf, fi);
3264                         ret = process_func(trans, root, bytenr, num_bytes,
3265                                            parent, ref_root, key.objectid,
3266                                            key.offset);
3267                         if (ret)
3268                                 goto fail;
3269                 } else {
3270                         bytenr = btrfs_node_blockptr(buf, i);
3271                         num_bytes = fs_info->nodesize;
3272                         ret = process_func(trans, root, bytenr, num_bytes,
3273                                            parent, ref_root, level - 1, 0);
3274                         if (ret)
3275                                 goto fail;
3276                 }
3277         }
3278         return 0;
3279 fail:
3280         return ret;
3281 }
3282
3283 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3284                   struct extent_buffer *buf, int full_backref)
3285 {
3286         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3287 }
3288
3289 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3290                   struct extent_buffer *buf, int full_backref)
3291 {
3292         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3293 }
3294
3295 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3296                                  struct btrfs_fs_info *fs_info,
3297                                  struct btrfs_path *path,
3298                                  struct btrfs_block_group_cache *cache)
3299 {
3300         int ret;
3301         struct btrfs_root *extent_root = fs_info->extent_root;
3302         unsigned long bi;
3303         struct extent_buffer *leaf;
3304
3305         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3306         if (ret) {
3307                 if (ret > 0)
3308                         ret = -ENOENT;
3309                 goto fail;
3310         }
3311
3312         leaf = path->nodes[0];
3313         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3314         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3315         btrfs_mark_buffer_dirty(leaf);
3316 fail:
3317         btrfs_release_path(path);
3318         return ret;
3319
3320 }
3321
3322 static struct btrfs_block_group_cache *
3323 next_block_group(struct btrfs_fs_info *fs_info,
3324                  struct btrfs_block_group_cache *cache)
3325 {
3326         struct rb_node *node;
3327
3328         spin_lock(&fs_info->block_group_cache_lock);
3329
3330         /* If our block group was removed, we need a full search. */
3331         if (RB_EMPTY_NODE(&cache->cache_node)) {
3332                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3333
3334                 spin_unlock(&fs_info->block_group_cache_lock);
3335                 btrfs_put_block_group(cache);
3336                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
3337         }
3338         node = rb_next(&cache->cache_node);
3339         btrfs_put_block_group(cache);
3340         if (node) {
3341                 cache = rb_entry(node, struct btrfs_block_group_cache,
3342                                  cache_node);
3343                 btrfs_get_block_group(cache);
3344         } else
3345                 cache = NULL;
3346         spin_unlock(&fs_info->block_group_cache_lock);
3347         return cache;
3348 }
3349
3350 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3351                             struct btrfs_trans_handle *trans,
3352                             struct btrfs_path *path)
3353 {
3354         struct btrfs_fs_info *fs_info = block_group->fs_info;
3355         struct btrfs_root *root = fs_info->tree_root;
3356         struct inode *inode = NULL;
3357         struct extent_changeset *data_reserved = NULL;
3358         u64 alloc_hint = 0;
3359         int dcs = BTRFS_DC_ERROR;
3360         u64 num_pages = 0;
3361         int retries = 0;
3362         int ret = 0;
3363
3364         /*
3365          * If this block group is smaller than 100 megs don't bother caching the
3366          * block group.
3367          */
3368         if (block_group->key.offset < (100 * SZ_1M)) {
3369                 spin_lock(&block_group->lock);
3370                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3371                 spin_unlock(&block_group->lock);
3372                 return 0;
3373         }
3374
3375         if (trans->aborted)
3376                 return 0;
3377 again:
3378         inode = lookup_free_space_inode(fs_info, block_group, path);
3379         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3380                 ret = PTR_ERR(inode);
3381                 btrfs_release_path(path);
3382                 goto out;
3383         }
3384
3385         if (IS_ERR(inode)) {
3386                 BUG_ON(retries);
3387                 retries++;
3388
3389                 if (block_group->ro)
3390                         goto out_free;
3391
3392                 ret = create_free_space_inode(fs_info, trans, block_group,
3393                                               path);
3394                 if (ret)
3395                         goto out_free;
3396                 goto again;
3397         }
3398
3399         /*
3400          * We want to set the generation to 0, that way if anything goes wrong
3401          * from here on out we know not to trust this cache when we load up next
3402          * time.
3403          */
3404         BTRFS_I(inode)->generation = 0;
3405         ret = btrfs_update_inode(trans, root, inode);
3406         if (ret) {
3407                 /*
3408                  * So theoretically we could recover from this, simply set the
3409                  * super cache generation to 0 so we know to invalidate the
3410                  * cache, but then we'd have to keep track of the block groups
3411                  * that fail this way so we know we _have_ to reset this cache
3412                  * before the next commit or risk reading stale cache.  So to
3413                  * limit our exposure to horrible edge cases lets just abort the
3414                  * transaction, this only happens in really bad situations
3415                  * anyway.
3416                  */
3417                 btrfs_abort_transaction(trans, ret);
3418                 goto out_put;
3419         }
3420         WARN_ON(ret);
3421
3422         /* We've already setup this transaction, go ahead and exit */
3423         if (block_group->cache_generation == trans->transid &&
3424             i_size_read(inode)) {
3425                 dcs = BTRFS_DC_SETUP;
3426                 goto out_put;
3427         }
3428
3429         if (i_size_read(inode) > 0) {
3430                 ret = btrfs_check_trunc_cache_free_space(fs_info,
3431                                         &fs_info->global_block_rsv);
3432                 if (ret)
3433                         goto out_put;
3434
3435                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3436                 if (ret)
3437                         goto out_put;
3438         }
3439
3440         spin_lock(&block_group->lock);
3441         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3442             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3443                 /*
3444                  * don't bother trying to write stuff out _if_
3445                  * a) we're not cached,
3446                  * b) we're with nospace_cache mount option,
3447                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
3448                  */
3449                 dcs = BTRFS_DC_WRITTEN;
3450                 spin_unlock(&block_group->lock);
3451                 goto out_put;
3452         }
3453         spin_unlock(&block_group->lock);
3454
3455         /*
3456          * We hit an ENOSPC when setting up the cache in this transaction, just
3457          * skip doing the setup, we've already cleared the cache so we're safe.
3458          */
3459         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3460                 ret = -ENOSPC;
3461                 goto out_put;
3462         }
3463
3464         /*
3465          * Try to preallocate enough space based on how big the block group is.
3466          * Keep in mind this has to include any pinned space which could end up
3467          * taking up quite a bit since it's not folded into the other space
3468          * cache.
3469          */
3470         num_pages = div_u64(block_group->key.offset, SZ_256M);
3471         if (!num_pages)
3472                 num_pages = 1;
3473
3474         num_pages *= 16;
3475         num_pages *= PAGE_SIZE;
3476
3477         ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
3478         if (ret)
3479                 goto out_put;
3480
3481         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3482                                               num_pages, num_pages,
3483                                               &alloc_hint);
3484         /*
3485          * Our cache requires contiguous chunks so that we don't modify a bunch
3486          * of metadata or split extents when writing the cache out, which means
3487          * we can enospc if we are heavily fragmented in addition to just normal
3488          * out of space conditions.  So if we hit this just skip setting up any
3489          * other block groups for this transaction, maybe we'll unpin enough
3490          * space the next time around.
3491          */
3492         if (!ret)
3493                 dcs = BTRFS_DC_SETUP;
3494         else if (ret == -ENOSPC)
3495                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3496
3497 out_put:
3498         iput(inode);
3499 out_free:
3500         btrfs_release_path(path);
3501 out:
3502         spin_lock(&block_group->lock);
3503         if (!ret && dcs == BTRFS_DC_SETUP)
3504                 block_group->cache_generation = trans->transid;
3505         block_group->disk_cache_state = dcs;
3506         spin_unlock(&block_group->lock);
3507
3508         extent_changeset_free(data_reserved);
3509         return ret;
3510 }
3511
3512 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3513                             struct btrfs_fs_info *fs_info)
3514 {
3515         struct btrfs_block_group_cache *cache, *tmp;
3516         struct btrfs_transaction *cur_trans = trans->transaction;
3517         struct btrfs_path *path;
3518
3519         if (list_empty(&cur_trans->dirty_bgs) ||
3520             !btrfs_test_opt(fs_info, SPACE_CACHE))
3521                 return 0;
3522
3523         path = btrfs_alloc_path();
3524         if (!path)
3525                 return -ENOMEM;
3526
3527         /* Could add new block groups, use _safe just in case */
3528         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3529                                  dirty_list) {
3530                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3531                         cache_save_setup(cache, trans, path);
3532         }
3533
3534         btrfs_free_path(path);
3535         return 0;
3536 }
3537
3538 /*
3539  * transaction commit does final block group cache writeback during a
3540  * critical section where nothing is allowed to change the FS.  This is
3541  * required in order for the cache to actually match the block group,
3542  * but can introduce a lot of latency into the commit.
3543  *
3544  * So, btrfs_start_dirty_block_groups is here to kick off block group
3545  * cache IO.  There's a chance we'll have to redo some of it if the
3546  * block group changes again during the commit, but it greatly reduces
3547  * the commit latency by getting rid of the easy block groups while
3548  * we're still allowing others to join the commit.
3549  */
3550 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
3551 {
3552         struct btrfs_fs_info *fs_info = trans->fs_info;
3553         struct btrfs_block_group_cache *cache;
3554         struct btrfs_transaction *cur_trans = trans->transaction;
3555         int ret = 0;
3556         int should_put;
3557         struct btrfs_path *path = NULL;
3558         LIST_HEAD(dirty);
3559         struct list_head *io = &cur_trans->io_bgs;
3560         int num_started = 0;
3561         int loops = 0;
3562
3563         spin_lock(&cur_trans->dirty_bgs_lock);
3564         if (list_empty(&cur_trans->dirty_bgs)) {
3565                 spin_unlock(&cur_trans->dirty_bgs_lock);
3566                 return 0;
3567         }
3568         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3569         spin_unlock(&cur_trans->dirty_bgs_lock);
3570
3571 again:
3572         /*
3573          * make sure all the block groups on our dirty list actually
3574          * exist
3575          */
3576         btrfs_create_pending_block_groups(trans);
3577
3578         if (!path) {
3579                 path = btrfs_alloc_path();
3580                 if (!path)
3581                         return -ENOMEM;
3582         }
3583
3584         /*
3585          * cache_write_mutex is here only to save us from balance or automatic
3586          * removal of empty block groups deleting this block group while we are
3587          * writing out the cache
3588          */
3589         mutex_lock(&trans->transaction->cache_write_mutex);
3590         while (!list_empty(&dirty)) {
3591                 cache = list_first_entry(&dirty,
3592                                          struct btrfs_block_group_cache,
3593                                          dirty_list);
3594                 /*
3595                  * this can happen if something re-dirties a block
3596                  * group that is already under IO.  Just wait for it to
3597                  * finish and then do it all again
3598                  */
3599                 if (!list_empty(&cache->io_list)) {
3600                         list_del_init(&cache->io_list);
3601                         btrfs_wait_cache_io(trans, cache, path);
3602                         btrfs_put_block_group(cache);
3603                 }
3604
3605
3606                 /*
3607                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3608                  * if it should update the cache_state.  Don't delete
3609                  * until after we wait.
3610                  *
3611                  * Since we're not running in the commit critical section
3612                  * we need the dirty_bgs_lock to protect from update_block_group
3613                  */
3614                 spin_lock(&cur_trans->dirty_bgs_lock);
3615                 list_del_init(&cache->dirty_list);
3616                 spin_unlock(&cur_trans->dirty_bgs_lock);
3617
3618                 should_put = 1;
3619
3620                 cache_save_setup(cache, trans, path);
3621
3622                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3623                         cache->io_ctl.inode = NULL;
3624                         ret = btrfs_write_out_cache(fs_info, trans,
3625                                                     cache, path);
3626                         if (ret == 0 && cache->io_ctl.inode) {
3627                                 num_started++;
3628                                 should_put = 0;
3629
3630                                 /*
3631                                  * The cache_write_mutex is protecting the
3632                                  * io_list, also refer to the definition of
3633                                  * btrfs_transaction::io_bgs for more details
3634                                  */
3635                                 list_add_tail(&cache->io_list, io);
3636                         } else {
3637                                 /*
3638                                  * if we failed to write the cache, the
3639                                  * generation will be bad and life goes on
3640                                  */
3641                                 ret = 0;
3642                         }
3643                 }
3644                 if (!ret) {
3645                         ret = write_one_cache_group(trans, fs_info,
3646                                                     path, cache);
3647                         /*
3648                          * Our block group might still be attached to the list
3649                          * of new block groups in the transaction handle of some
3650                          * other task (struct btrfs_trans_handle->new_bgs). This
3651                          * means its block group item isn't yet in the extent
3652                          * tree. If this happens ignore the error, as we will
3653                          * try again later in the critical section of the
3654                          * transaction commit.
3655                          */
3656                         if (ret == -ENOENT) {
3657                                 ret = 0;
3658                                 spin_lock(&cur_trans->dirty_bgs_lock);
3659                                 if (list_empty(&cache->dirty_list)) {
3660                                         list_add_tail(&cache->dirty_list,
3661                                                       &cur_trans->dirty_bgs);
3662                                         btrfs_get_block_group(cache);
3663                                 }
3664                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3665                         } else if (ret) {
3666                                 btrfs_abort_transaction(trans, ret);
3667                         }
3668                 }
3669
3670                 /* if its not on the io list, we need to put the block group */
3671                 if (should_put)
3672                         btrfs_put_block_group(cache);
3673
3674                 if (ret)
3675                         break;
3676
3677                 /*
3678                  * Avoid blocking other tasks for too long. It might even save
3679                  * us from writing caches for block groups that are going to be
3680                  * removed.
3681                  */
3682                 mutex_unlock(&trans->transaction->cache_write_mutex);
3683                 mutex_lock(&trans->transaction->cache_write_mutex);
3684         }
3685         mutex_unlock(&trans->transaction->cache_write_mutex);
3686
3687         /*
3688          * go through delayed refs for all the stuff we've just kicked off
3689          * and then loop back (just once)
3690          */
3691         ret = btrfs_run_delayed_refs(trans, 0);
3692         if (!ret && loops == 0) {
3693                 loops++;
3694                 spin_lock(&cur_trans->dirty_bgs_lock);
3695                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3696                 /*
3697                  * dirty_bgs_lock protects us from concurrent block group
3698                  * deletes too (not just cache_write_mutex).
3699                  */
3700                 if (!list_empty(&dirty)) {
3701                         spin_unlock(&cur_trans->dirty_bgs_lock);
3702                         goto again;
3703                 }
3704                 spin_unlock(&cur_trans->dirty_bgs_lock);
3705         } else if (ret < 0) {
3706                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3707         }
3708
3709         btrfs_free_path(path);
3710         return ret;
3711 }
3712
3713 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3714                                    struct btrfs_fs_info *fs_info)
3715 {
3716         struct btrfs_block_group_cache *cache;
3717         struct btrfs_transaction *cur_trans = trans->transaction;
3718         int ret = 0;
3719         int should_put;
3720         struct btrfs_path *path;
3721         struct list_head *io = &cur_trans->io_bgs;
3722         int num_started = 0;
3723
3724         path = btrfs_alloc_path();
3725         if (!path)
3726                 return -ENOMEM;
3727
3728         /*
3729          * Even though we are in the critical section of the transaction commit,
3730          * we can still have concurrent tasks adding elements to this
3731          * transaction's list of dirty block groups. These tasks correspond to
3732          * endio free space workers started when writeback finishes for a
3733          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3734          * allocate new block groups as a result of COWing nodes of the root
3735          * tree when updating the free space inode. The writeback for the space
3736          * caches is triggered by an earlier call to
3737          * btrfs_start_dirty_block_groups() and iterations of the following
3738          * loop.
3739          * Also we want to do the cache_save_setup first and then run the
3740          * delayed refs to make sure we have the best chance at doing this all
3741          * in one shot.
3742          */
3743         spin_lock(&cur_trans->dirty_bgs_lock);
3744         while (!list_empty(&cur_trans->dirty_bgs)) {
3745                 cache = list_first_entry(&cur_trans->dirty_bgs,
3746                                          struct btrfs_block_group_cache,
3747                                          dirty_list);
3748
3749                 /*
3750                  * this can happen if cache_save_setup re-dirties a block
3751                  * group that is already under IO.  Just wait for it to
3752                  * finish and then do it all again
3753                  */
3754                 if (!list_empty(&cache->io_list)) {
3755                         spin_unlock(&cur_trans->dirty_bgs_lock);
3756                         list_del_init(&cache->io_list);
3757                         btrfs_wait_cache_io(trans, cache, path);
3758                         btrfs_put_block_group(cache);
3759                         spin_lock(&cur_trans->dirty_bgs_lock);
3760                 }
3761
3762                 /*
3763                  * don't remove from the dirty list until after we've waited
3764                  * on any pending IO
3765                  */
3766                 list_del_init(&cache->dirty_list);
3767                 spin_unlock(&cur_trans->dirty_bgs_lock);
3768                 should_put = 1;
3769
3770                 cache_save_setup(cache, trans, path);
3771
3772                 if (!ret)
3773                         ret = btrfs_run_delayed_refs(trans,
3774                                                      (unsigned long) -1);
3775
3776                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3777                         cache->io_ctl.inode = NULL;
3778                         ret = btrfs_write_out_cache(fs_info, trans,
3779                                                     cache, path);
3780                         if (ret == 0 && cache->io_ctl.inode) {
3781                                 num_started++;
3782                                 should_put = 0;
3783                                 list_add_tail(&cache->io_list, io);
3784                         } else {
3785                                 /*
3786                                  * if we failed to write the cache, the
3787                                  * generation will be bad and life goes on
3788                                  */
3789                                 ret = 0;
3790                         }
3791                 }
3792                 if (!ret) {
3793                         ret = write_one_cache_group(trans, fs_info,
3794                                                     path, cache);
3795                         /*
3796                          * One of the free space endio workers might have
3797                          * created a new block group while updating a free space
3798                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3799                          * and hasn't released its transaction handle yet, in
3800                          * which case the new block group is still attached to
3801                          * its transaction handle and its creation has not
3802                          * finished yet (no block group item in the extent tree
3803                          * yet, etc). If this is the case, wait for all free
3804                          * space endio workers to finish and retry. This is a
3805                          * a very rare case so no need for a more efficient and
3806                          * complex approach.
3807                          */
3808                         if (ret == -ENOENT) {
3809                                 wait_event(cur_trans->writer_wait,
3810                                    atomic_read(&cur_trans->num_writers) == 1);
3811                                 ret = write_one_cache_group(trans, fs_info,
3812                                                             path, cache);
3813                         }
3814                         if (ret)
3815                                 btrfs_abort_transaction(trans, ret);
3816                 }
3817
3818                 /* if its not on the io list, we need to put the block group */
3819                 if (should_put)
3820                         btrfs_put_block_group(cache);
3821                 spin_lock(&cur_trans->dirty_bgs_lock);
3822         }
3823         spin_unlock(&cur_trans->dirty_bgs_lock);
3824
3825         /*
3826          * Refer to the definition of io_bgs member for details why it's safe
3827          * to use it without any locking
3828          */
3829         while (!list_empty(io)) {
3830                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3831                                          io_list);
3832                 list_del_init(&cache->io_list);
3833                 btrfs_wait_cache_io(trans, cache, path);
3834                 btrfs_put_block_group(cache);
3835         }
3836
3837         btrfs_free_path(path);
3838         return ret;
3839 }
3840
3841 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
3842 {
3843         struct btrfs_block_group_cache *block_group;
3844         int readonly = 0;
3845
3846         block_group = btrfs_lookup_block_group(fs_info, bytenr);
3847         if (!block_group || block_group->ro)
3848                 readonly = 1;
3849         if (block_group)
3850                 btrfs_put_block_group(block_group);
3851         return readonly;
3852 }
3853
3854 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3855 {
3856         struct btrfs_block_group_cache *bg;
3857         bool ret = true;
3858
3859         bg = btrfs_lookup_block_group(fs_info, bytenr);
3860         if (!bg)
3861                 return false;
3862
3863         spin_lock(&bg->lock);
3864         if (bg->ro)
3865                 ret = false;
3866         else
3867                 atomic_inc(&bg->nocow_writers);
3868         spin_unlock(&bg->lock);
3869
3870         /* no put on block group, done by btrfs_dec_nocow_writers */
3871         if (!ret)
3872                 btrfs_put_block_group(bg);
3873
3874         return ret;
3875
3876 }
3877
3878 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3879 {
3880         struct btrfs_block_group_cache *bg;
3881
3882         bg = btrfs_lookup_block_group(fs_info, bytenr);
3883         ASSERT(bg);
3884         if (atomic_dec_and_test(&bg->nocow_writers))
3885                 wake_up_var(&bg->nocow_writers);
3886         /*
3887          * Once for our lookup and once for the lookup done by a previous call
3888          * to btrfs_inc_nocow_writers()
3889          */
3890         btrfs_put_block_group(bg);
3891         btrfs_put_block_group(bg);
3892 }
3893
3894 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3895 {
3896         wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
3897 }
3898
3899 static const char *alloc_name(u64 flags)
3900 {
3901         switch (flags) {
3902         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3903                 return "mixed";
3904         case BTRFS_BLOCK_GROUP_METADATA:
3905                 return "metadata";
3906         case BTRFS_BLOCK_GROUP_DATA:
3907                 return "data";
3908         case BTRFS_BLOCK_GROUP_SYSTEM:
3909                 return "system";
3910         default:
3911                 WARN_ON(1);
3912                 return "invalid-combination";
3913         };
3914 }
3915
3916 static int create_space_info(struct btrfs_fs_info *info, u64 flags)
3917 {
3918
3919         struct btrfs_space_info *space_info;
3920         int i;
3921         int ret;
3922
3923         space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
3924         if (!space_info)
3925                 return -ENOMEM;
3926
3927         ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
3928                                  GFP_KERNEL);
3929         if (ret) {
3930                 kfree(space_info);
3931                 return ret;
3932         }
3933
3934         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3935                 INIT_LIST_HEAD(&space_info->block_groups[i]);
3936         init_rwsem(&space_info->groups_sem);
3937         spin_lock_init(&space_info->lock);
3938         space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3939         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3940         init_waitqueue_head(&space_info->wait);
3941         INIT_LIST_HEAD(&space_info->ro_bgs);
3942         INIT_LIST_HEAD(&space_info->tickets);
3943         INIT_LIST_HEAD(&space_info->priority_tickets);
3944
3945         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
3946                                     info->space_info_kobj, "%s",
3947                                     alloc_name(space_info->flags));
3948         if (ret) {
3949                 percpu_counter_destroy(&space_info->total_bytes_pinned);
3950                 kfree(space_info);
3951                 return ret;
3952         }
3953
3954         list_add_rcu(&space_info->list, &info->space_info);
3955         if (flags & BTRFS_BLOCK_GROUP_DATA)
3956                 info->data_sinfo = space_info;
3957
3958         return ret;
3959 }
3960
3961 static void update_space_info(struct btrfs_fs_info *info, u64 flags,
3962                              u64 total_bytes, u64 bytes_used,
3963                              u64 bytes_readonly,
3964                              struct btrfs_space_info **space_info)
3965 {
3966         struct btrfs_space_info *found;
3967         int factor;
3968
3969         factor = btrfs_bg_type_to_factor(flags);
3970
3971         found = __find_space_info(info, flags);
3972         ASSERT(found);
3973         spin_lock(&found->lock);
3974         found->total_bytes += total_bytes;
3975         found->disk_total += total_bytes * factor;
3976         found->bytes_used += bytes_used;
3977         found->disk_used += bytes_used * factor;
3978         found->bytes_readonly += bytes_readonly;
3979         if (total_bytes > 0)
3980                 found->full = 0;
3981         space_info_add_new_bytes(info, found, total_bytes -
3982                                  bytes_used - bytes_readonly);
3983         spin_unlock(&found->lock);
3984         *space_info = found;
3985 }
3986
3987 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3988 {
3989         u64 extra_flags = chunk_to_extended(flags) &
3990                                 BTRFS_EXTENDED_PROFILE_MASK;
3991
3992         write_seqlock(&fs_info->profiles_lock);
3993         if (flags & BTRFS_BLOCK_GROUP_DATA)
3994                 fs_info->avail_data_alloc_bits |= extra_flags;
3995         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3996                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3997         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3998                 fs_info->avail_system_alloc_bits |= extra_flags;
3999         write_sequnlock(&fs_info->profiles_lock);
4000 }
4001
4002 /*
4003  * returns target flags in extended format or 0 if restripe for this
4004  * chunk_type is not in progress
4005  *
4006  * should be called with balance_lock held
4007  */
4008 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4009 {
4010         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4011         u64 target = 0;
4012
4013         if (!bctl)
4014                 return 0;
4015
4016         if (flags & BTRFS_BLOCK_GROUP_DATA &&
4017             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4018                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4019         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4020                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4021                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4022         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4023                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4024                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4025         }
4026
4027         return target;
4028 }
4029
4030 /*
4031  * @flags: available profiles in extended format (see ctree.h)
4032  *
4033  * Returns reduced profile in chunk format.  If profile changing is in
4034  * progress (either running or paused) picks the target profile (if it's
4035  * already available), otherwise falls back to plain reducing.
4036  */
4037 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
4038 {
4039         u64 num_devices = fs_info->fs_devices->rw_devices;
4040         u64 target;
4041         u64 raid_type;
4042         u64 allowed = 0;
4043
4044         /*
4045          * see if restripe for this chunk_type is in progress, if so
4046          * try to reduce to the target profile
4047          */
4048         spin_lock(&fs_info->balance_lock);
4049         target = get_restripe_target(fs_info, flags);
4050         if (target) {
4051                 /* pick target profile only if it's already available */
4052                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4053                         spin_unlock(&fs_info->balance_lock);
4054                         return extended_to_chunk(target);
4055                 }
4056         }
4057         spin_unlock(&fs_info->balance_lock);
4058
4059         /* First, mask out the RAID levels which aren't possible */
4060         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4061                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4062                         allowed |= btrfs_raid_array[raid_type].bg_flag;
4063         }
4064         allowed &= flags;
4065
4066         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4067                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4068         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4069                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4070         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4071                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4072         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4073                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4074         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4075                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4076
4077         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4078
4079         return extended_to_chunk(flags | allowed);
4080 }
4081
4082 static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
4083 {
4084         unsigned seq;
4085         u64 flags;
4086
4087         do {
4088                 flags = orig_flags;
4089                 seq = read_seqbegin(&fs_info->profiles_lock);
4090
4091                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4092                         flags |= fs_info->avail_data_alloc_bits;
4093                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4094                         flags |= fs_info->avail_system_alloc_bits;
4095                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4096                         flags |= fs_info->avail_metadata_alloc_bits;
4097         } while (read_seqretry(&fs_info->profiles_lock, seq));
4098
4099         return btrfs_reduce_alloc_profile(fs_info, flags);
4100 }
4101
4102 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
4103 {
4104         struct btrfs_fs_info *fs_info = root->fs_info;
4105         u64 flags;
4106         u64 ret;
4107
4108         if (data)
4109                 flags = BTRFS_BLOCK_GROUP_DATA;
4110         else if (root == fs_info->chunk_root)
4111                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4112         else
4113                 flags = BTRFS_BLOCK_GROUP_METADATA;
4114
4115         ret = get_alloc_profile(fs_info, flags);
4116         return ret;
4117 }
4118
4119 u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
4120 {
4121         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
4122 }
4123
4124 u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
4125 {
4126         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4127 }
4128
4129 u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
4130 {
4131         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4132 }
4133
4134 static u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
4135                                  bool may_use_included)
4136 {
4137         ASSERT(s_info);
4138         return s_info->bytes_used + s_info->bytes_reserved +
4139                 s_info->bytes_pinned + s_info->bytes_readonly +
4140                 (may_use_included ? s_info->bytes_may_use : 0);
4141 }
4142
4143 int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes)
4144 {
4145         struct btrfs_root *root = inode->root;
4146         struct btrfs_fs_info *fs_info = root->fs_info;
4147         struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
4148         u64 used;
4149         int ret = 0;
4150         int need_commit = 2;
4151         int have_pinned_space;
4152
4153         /* make sure bytes are sectorsize aligned */
4154         bytes = ALIGN(bytes, fs_info->sectorsize);
4155
4156         if (btrfs_is_free_space_inode(inode)) {
4157                 need_commit = 0;
4158                 ASSERT(current->journal_info);
4159         }
4160
4161 again:
4162         /* make sure we have enough space to handle the data first */
4163         spin_lock(&data_sinfo->lock);
4164         used = btrfs_space_info_used(data_sinfo, true);
4165
4166         if (used + bytes > data_sinfo->total_bytes) {
4167                 struct btrfs_trans_handle *trans;
4168
4169                 /*
4170                  * if we don't have enough free bytes in this space then we need
4171                  * to alloc a new chunk.
4172                  */
4173                 if (!data_sinfo->full) {
4174                         u64 alloc_target;
4175
4176                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4177                         spin_unlock(&data_sinfo->lock);
4178
4179                         alloc_target = btrfs_data_alloc_profile(fs_info);
4180                         /*
4181                          * It is ugly that we don't call nolock join
4182                          * transaction for the free space inode case here.
4183                          * But it is safe because we only do the data space
4184                          * reservation for the free space cache in the
4185                          * transaction context, the common join transaction
4186                          * just increase the counter of the current transaction
4187                          * handler, doesn't try to acquire the trans_lock of
4188                          * the fs.
4189                          */
4190                         trans = btrfs_join_transaction(root);
4191                         if (IS_ERR(trans))
4192                                 return PTR_ERR(trans);
4193
4194                         ret = do_chunk_alloc(trans, alloc_target,
4195                                              CHUNK_ALLOC_NO_FORCE);
4196                         btrfs_end_transaction(trans);
4197                         if (ret < 0) {
4198                                 if (ret != -ENOSPC)
4199                                         return ret;
4200                                 else {
4201                                         have_pinned_space = 1;
4202                                         goto commit_trans;
4203                                 }
4204                         }
4205
4206                         goto again;
4207                 }
4208
4209                 /*
4210                  * If we don't have enough pinned space to deal with this
4211                  * allocation, and no removed chunk in current transaction,
4212                  * don't bother committing the transaction.
4213                  */
4214                 have_pinned_space = __percpu_counter_compare(
4215                         &data_sinfo->total_bytes_pinned,
4216                         used + bytes - data_sinfo->total_bytes,
4217                         BTRFS_TOTAL_BYTES_PINNED_BATCH);
4218                 spin_unlock(&data_sinfo->lock);
4219
4220                 /* commit the current transaction and try again */
4221 commit_trans:
4222                 if (need_commit) {
4223                         need_commit--;
4224
4225                         if (need_commit > 0) {
4226                                 btrfs_start_delalloc_roots(fs_info, -1);
4227                                 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
4228                                                          (u64)-1);
4229                         }
4230
4231                         trans = btrfs_join_transaction(root);
4232                         if (IS_ERR(trans))
4233                                 return PTR_ERR(trans);
4234                         if (have_pinned_space >= 0 ||
4235                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4236                                      &trans->transaction->flags) ||
4237                             need_commit > 0) {
4238                                 ret = btrfs_commit_transaction(trans);
4239                                 if (ret)
4240                                         return ret;
4241                                 /*
4242                                  * The cleaner kthread might still be doing iput
4243                                  * operations. Wait for it to finish so that
4244                                  * more space is released.
4245                                  */
4246                                 mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
4247                                 mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
4248                                 goto again;
4249                         } else {
4250                                 btrfs_end_transaction(trans);
4251                         }
4252                 }
4253
4254                 trace_btrfs_space_reservation(fs_info,
4255                                               "space_info:enospc",
4256                                               data_sinfo->flags, bytes, 1);
4257                 return -ENOSPC;
4258         }
4259         data_sinfo->bytes_may_use += bytes;
4260         trace_btrfs_space_reservation(fs_info, "space_info",
4261                                       data_sinfo->flags, bytes, 1);
4262         spin_unlock(&data_sinfo->lock);
4263
4264         return 0;
4265 }
4266
4267 int btrfs_check_data_free_space(struct inode *inode,
4268                         struct extent_changeset **reserved, u64 start, u64 len)
4269 {
4270         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4271         int ret;
4272
4273         /* align the range */
4274         len = round_up(start + len, fs_info->sectorsize) -
4275               round_down(start, fs_info->sectorsize);
4276         start = round_down(start, fs_info->sectorsize);
4277
4278         ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), len);
4279         if (ret < 0)
4280                 return ret;
4281
4282         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4283         ret = btrfs_qgroup_reserve_data(inode, reserved, start, len);
4284         if (ret < 0)
4285                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4286         else
4287                 ret = 0;
4288         return ret;
4289 }
4290
4291 /*
4292  * Called if we need to clear a data reservation for this inode
4293  * Normally in a error case.
4294  *
4295  * This one will *NOT* use accurate qgroup reserved space API, just for case
4296  * which we can't sleep and is sure it won't affect qgroup reserved space.
4297  * Like clear_bit_hook().
4298  */
4299 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4300                                             u64 len)
4301 {
4302         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4303         struct btrfs_space_info *data_sinfo;
4304
4305         /* Make sure the range is aligned to sectorsize */
4306         len = round_up(start + len, fs_info->sectorsize) -
4307               round_down(start, fs_info->sectorsize);
4308         start = round_down(start, fs_info->sectorsize);
4309
4310         data_sinfo = fs_info->data_sinfo;
4311         spin_lock(&data_sinfo->lock);
4312         if (WARN_ON(data_sinfo->bytes_may_use < len))
4313                 data_sinfo->bytes_may_use = 0;
4314         else
4315                 data_sinfo->bytes_may_use -= len;
4316         trace_btrfs_space_reservation(fs_info, "space_info",
4317                                       data_sinfo->flags, len, 0);
4318         spin_unlock(&data_sinfo->lock);
4319 }
4320
4321 /*
4322  * Called if we need to clear a data reservation for this inode
4323  * Normally in a error case.
4324  *
4325  * This one will handle the per-inode data rsv map for accurate reserved
4326  * space framework.
4327  */
4328 void btrfs_free_reserved_data_space(struct inode *inode,
4329                         struct extent_changeset *reserved, u64 start, u64 len)
4330 {
4331         struct btrfs_root *root = BTRFS_I(inode)->root;
4332
4333         /* Make sure the range is aligned to sectorsize */
4334         len = round_up(start + len, root->fs_info->sectorsize) -
4335               round_down(start, root->fs_info->sectorsize);
4336         start = round_down(start, root->fs_info->sectorsize);
4337
4338         btrfs_free_reserved_data_space_noquota(inode, start, len);
4339         btrfs_qgroup_free_data(inode, reserved, start, len);
4340 }
4341
4342 static void force_metadata_allocation(struct btrfs_fs_info *info)
4343 {
4344         struct list_head *head = &info->space_info;
4345         struct btrfs_space_info *found;
4346
4347         rcu_read_lock();
4348         list_for_each_entry_rcu(found, head, list) {
4349                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4350                         found->force_alloc = CHUNK_ALLOC_FORCE;
4351         }
4352         rcu_read_unlock();
4353 }
4354
4355 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4356 {
4357         return (global->size << 1);
4358 }
4359
4360 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
4361                               struct btrfs_space_info *sinfo, int force)
4362 {
4363         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4364         u64 bytes_used = btrfs_space_info_used(sinfo, false);
4365         u64 thresh;
4366
4367         if (force == CHUNK_ALLOC_FORCE)
4368                 return 1;
4369
4370         /*
4371          * We need to take into account the global rsv because for all intents
4372          * and purposes it's used space.  Don't worry about locking the
4373          * global_rsv, it doesn't change except when the transaction commits.
4374          */
4375         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4376                 bytes_used += calc_global_rsv_need_space(global_rsv);
4377
4378         /*
4379          * in limited mode, we want to have some free space up to
4380          * about 1% of the FS size.
4381          */
4382         if (force == CHUNK_ALLOC_LIMITED) {
4383                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
4384                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4385
4386                 if (sinfo->total_bytes - bytes_used < thresh)
4387                         return 1;
4388         }
4389
4390         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
4391                 return 0;
4392         return 1;
4393 }
4394
4395 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4396 {
4397         u64 num_dev;
4398
4399         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4400                     BTRFS_BLOCK_GROUP_RAID0 |
4401                     BTRFS_BLOCK_GROUP_RAID5 |
4402                     BTRFS_BLOCK_GROUP_RAID6))
4403                 num_dev = fs_info->fs_devices->rw_devices;
4404         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4405                 num_dev = 2;
4406         else
4407                 num_dev = 1;    /* DUP or single */
4408
4409         return num_dev;
4410 }
4411
4412 /*
4413  * If @is_allocation is true, reserve space in the system space info necessary
4414  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4415  * removing a chunk.
4416  */
4417 void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
4418 {
4419         struct btrfs_fs_info *fs_info = trans->fs_info;
4420         struct btrfs_space_info *info;
4421         u64 left;
4422         u64 thresh;
4423         int ret = 0;
4424         u64 num_devs;
4425
4426         /*
4427          * Needed because we can end up allocating a system chunk and for an
4428          * atomic and race free space reservation in the chunk block reserve.
4429          */
4430         lockdep_assert_held(&fs_info->chunk_mutex);
4431
4432         info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4433         spin_lock(&info->lock);
4434         left = info->total_bytes - btrfs_space_info_used(info, true);
4435         spin_unlock(&info->lock);
4436
4437         num_devs = get_profile_num_devs(fs_info, type);
4438
4439         /* num_devs device items to update and 1 chunk item to add or remove */
4440         thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
4441                 btrfs_calc_trans_metadata_size(fs_info, 1);
4442
4443         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4444                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4445                            left, thresh, type);
4446                 dump_space_info(fs_info, info, 0, 0);
4447         }
4448
4449         if (left < thresh) {
4450                 u64 flags = btrfs_system_alloc_profile(fs_info);
4451
4452                 /*
4453                  * Ignore failure to create system chunk. We might end up not
4454                  * needing it, as we might not need to COW all nodes/leafs from
4455                  * the paths we visit in the chunk tree (they were already COWed
4456                  * or created in the current transaction for example).
4457                  */
4458                 ret = btrfs_alloc_chunk(trans, flags);
4459         }
4460
4461         if (!ret) {
4462                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
4463                                           &fs_info->chunk_block_rsv,
4464                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4465                 if (!ret)
4466                         trans->chunk_bytes_reserved += thresh;
4467         }
4468 }
4469
4470 /*
4471  * If force is CHUNK_ALLOC_FORCE:
4472  *    - return 1 if it successfully allocates a chunk,
4473  *    - return errors including -ENOSPC otherwise.
4474  * If force is NOT CHUNK_ALLOC_FORCE:
4475  *    - return 0 if it doesn't need to allocate a new chunk,
4476  *    - return 1 if it successfully allocates a chunk,
4477  *    - return errors including -ENOSPC otherwise.
4478  */
4479 static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
4480                           int force)
4481 {
4482         struct btrfs_fs_info *fs_info = trans->fs_info;
4483         struct btrfs_space_info *space_info;
4484         bool wait_for_alloc = false;
4485         bool should_alloc = false;
4486         int ret = 0;
4487
4488         /* Don't re-enter if we're already allocating a chunk */
4489         if (trans->allocating_chunk)
4490                 return -ENOSPC;
4491
4492         space_info = __find_space_info(fs_info, flags);
4493         ASSERT(space_info);
4494
4495         do {
4496                 spin_lock(&space_info->lock);
4497                 if (force < space_info->force_alloc)
4498                         force = space_info->force_alloc;
4499                 should_alloc = should_alloc_chunk(fs_info, space_info, force);
4500                 if (space_info->full) {
4501                         /* No more free physical space */
4502                         if (should_alloc)
4503                                 ret = -ENOSPC;
4504                         else
4505                                 ret = 0;
4506                         spin_unlock(&space_info->lock);
4507                         return ret;
4508                 } else if (!should_alloc) {
4509                         spin_unlock(&space_info->lock);
4510                         return 0;
4511                 } else if (space_info->chunk_alloc) {
4512                         /*
4513                          * Someone is already allocating, so we need to block
4514                          * until this someone is finished and then loop to
4515                          * recheck if we should continue with our allocation
4516                          * attempt.
4517                          */
4518                         wait_for_alloc = true;
4519                         spin_unlock(&space_info->lock);
4520                         mutex_lock(&fs_info->chunk_mutex);
4521                         mutex_unlock(&fs_info->chunk_mutex);
4522                 } else {
4523                         /* Proceed with allocation */
4524                         space_info->chunk_alloc = 1;
4525                         wait_for_alloc = false;
4526                         spin_unlock(&space_info->lock);
4527                 }
4528
4529                 cond_resched();
4530         } while (wait_for_alloc);
4531
4532         mutex_lock(&fs_info->chunk_mutex);
4533         trans->allocating_chunk = true;
4534
4535         /*
4536          * If we have mixed data/metadata chunks we want to make sure we keep
4537          * allocating mixed chunks instead of individual chunks.
4538          */
4539         if (btrfs_mixed_space_info(space_info))
4540                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4541
4542         /*
4543          * if we're doing a data chunk, go ahead and make sure that
4544          * we keep a reasonable number of metadata chunks allocated in the
4545          * FS as well.
4546          */
4547         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4548                 fs_info->data_chunk_allocations++;
4549                 if (!(fs_info->data_chunk_allocations %
4550                       fs_info->metadata_ratio))
4551                         force_metadata_allocation(fs_info);
4552         }
4553
4554         /*
4555          * Check if we have enough space in SYSTEM chunk because we may need
4556          * to update devices.
4557          */
4558         check_system_chunk(trans, flags);
4559
4560         ret = btrfs_alloc_chunk(trans, flags);
4561         trans->allocating_chunk = false;
4562
4563         spin_lock(&space_info->lock);
4564         if (ret < 0) {
4565                 if (ret == -ENOSPC)
4566                         space_info->full = 1;
4567                 else
4568                         goto out;
4569         } else {
4570                 ret = 1;
4571                 space_info->max_extent_size = 0;
4572         }
4573
4574         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4575 out:
4576         space_info->chunk_alloc = 0;
4577         spin_unlock(&space_info->lock);
4578         mutex_unlock(&fs_info->chunk_mutex);
4579         /*
4580          * When we allocate a new chunk we reserve space in the chunk block
4581          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4582          * add new nodes/leafs to it if we end up needing to do it when
4583          * inserting the chunk item and updating device items as part of the
4584          * second phase of chunk allocation, performed by
4585          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4586          * large number of new block groups to create in our transaction
4587          * handle's new_bgs list to avoid exhausting the chunk block reserve
4588          * in extreme cases - like having a single transaction create many new
4589          * block groups when starting to write out the free space caches of all
4590          * the block groups that were made dirty during the lifetime of the
4591          * transaction.
4592          */
4593         if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
4594                 btrfs_create_pending_block_groups(trans);
4595
4596         return ret;
4597 }
4598
4599 static int can_overcommit(struct btrfs_fs_info *fs_info,
4600                           struct btrfs_space_info *space_info, u64 bytes,
4601                           enum btrfs_reserve_flush_enum flush,
4602                           bool system_chunk)
4603 {
4604         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4605         u64 profile;
4606         u64 space_size;
4607         u64 avail;
4608         u64 used;
4609         int factor;
4610
4611         /* Don't overcommit when in mixed mode. */
4612         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4613                 return 0;
4614
4615         if (system_chunk)
4616                 profile = btrfs_system_alloc_profile(fs_info);
4617         else
4618                 profile = btrfs_metadata_alloc_profile(fs_info);
4619
4620         used = btrfs_space_info_used(space_info, false);
4621
4622         /*
4623          * We only want to allow over committing if we have lots of actual space
4624          * free, but if we don't have enough space to handle the global reserve
4625          * space then we could end up having a real enospc problem when trying
4626          * to allocate a chunk or some other such important allocation.
4627          */
4628         spin_lock(&global_rsv->lock);
4629         space_size = calc_global_rsv_need_space(global_rsv);
4630         spin_unlock(&global_rsv->lock);
4631         if (used + space_size >= space_info->total_bytes)
4632                 return 0;
4633
4634         used += space_info->bytes_may_use;
4635
4636         avail = atomic64_read(&fs_info->free_chunk_space);
4637
4638         /*
4639          * If we have dup, raid1 or raid10 then only half of the free
4640          * space is actually useable.  For raid56, the space info used
4641          * doesn't include the parity drive, so we don't have to
4642          * change the math
4643          */
4644         factor = btrfs_bg_type_to_factor(profile);
4645         avail = div_u64(avail, factor);
4646
4647         /*
4648          * If we aren't flushing all things, let us overcommit up to
4649          * 1/2th of the space. If we can flush, don't let us overcommit
4650          * too much, let it overcommit up to 1/8 of the space.
4651          */
4652         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4653                 avail >>= 3;
4654         else
4655                 avail >>= 1;
4656
4657         if (used + bytes < space_info->total_bytes + avail)
4658                 return 1;
4659         return 0;
4660 }
4661
4662 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
4663                                          unsigned long nr_pages, int nr_items)
4664 {
4665         struct super_block *sb = fs_info->sb;
4666
4667         if (down_read_trylock(&sb->s_umount)) {
4668                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4669                 up_read(&sb->s_umount);
4670         } else {
4671                 /*
4672                  * We needn't worry the filesystem going from r/w to r/o though
4673                  * we don't acquire ->s_umount mutex, because the filesystem
4674                  * should guarantee the delalloc inodes list be empty after
4675                  * the filesystem is readonly(all dirty pages are written to
4676                  * the disk).
4677                  */
4678                 btrfs_start_delalloc_roots(fs_info, nr_items);
4679                 if (!current->journal_info)
4680                         btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
4681         }
4682 }
4683
4684 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
4685                                         u64 to_reclaim)
4686 {
4687         u64 bytes;
4688         u64 nr;
4689
4690         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
4691         nr = div64_u64(to_reclaim, bytes);
4692         if (!nr)
4693                 nr = 1;
4694         return nr;
4695 }
4696
4697 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4698
4699 /*
4700  * shrink metadata reservation for delalloc
4701  */
4702 static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
4703                             u64 orig, bool wait_ordered)
4704 {
4705         struct btrfs_space_info *space_info;
4706         struct btrfs_trans_handle *trans;
4707         u64 delalloc_bytes;
4708         u64 max_reclaim;
4709         u64 items;
4710         long time_left;
4711         unsigned long nr_pages;
4712         int loops;
4713
4714         /* Calc the number of the pages we need flush for space reservation */
4715         items = calc_reclaim_items_nr(fs_info, to_reclaim);
4716         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4717
4718         trans = (struct btrfs_trans_handle *)current->journal_info;
4719         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4720
4721         delalloc_bytes = percpu_counter_sum_positive(
4722                                                 &fs_info->delalloc_bytes);
4723         if (delalloc_bytes == 0) {
4724                 if (trans)
4725                         return;
4726                 if (wait_ordered)
4727                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4728                 return;
4729         }
4730
4731         loops = 0;
4732         while (delalloc_bytes && loops < 3) {
4733                 max_reclaim = min(delalloc_bytes, to_reclaim);
4734                 nr_pages = max_reclaim >> PAGE_SHIFT;
4735                 btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
4736                 /*
4737                  * We need to wait for the async pages to actually start before
4738                  * we do anything.
4739                  */
4740                 max_reclaim = atomic_read(&fs_info->async_delalloc_pages);
4741                 if (!max_reclaim)
4742                         goto skip_async;
4743
4744                 if (max_reclaim <= nr_pages)
4745                         max_reclaim = 0;
4746                 else
4747                         max_reclaim -= nr_pages;
4748
4749                 wait_event(fs_info->async_submit_wait,
4750                            atomic_read(&fs_info->async_delalloc_pages) <=
4751                            (int)max_reclaim);
4752 skip_async:
4753                 spin_lock(&space_info->lock);
4754                 if (list_empty(&space_info->tickets) &&
4755                     list_empty(&space_info->priority_tickets)) {
4756                         spin_unlock(&space_info->lock);
4757                         break;
4758                 }
4759                 spin_unlock(&space_info->lock);
4760
4761                 loops++;
4762                 if (wait_ordered && !trans) {
4763                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4764                 } else {
4765                         time_left = schedule_timeout_killable(1);
4766                         if (time_left)
4767                                 break;
4768                 }
4769                 delalloc_bytes = percpu_counter_sum_positive(
4770                                                 &fs_info->delalloc_bytes);
4771         }
4772 }
4773
4774 struct reserve_ticket {
4775         u64 bytes;
4776         int error;
4777         struct list_head list;
4778         wait_queue_head_t wait;
4779 };
4780
4781 /**
4782  * maybe_commit_transaction - possibly commit the transaction if its ok to
4783  * @root - the root we're allocating for
4784  * @bytes - the number of bytes we want to reserve
4785  * @force - force the commit
4786  *
4787  * This will check to make sure that committing the transaction will actually
4788  * get us somewhere and then commit the transaction if it does.  Otherwise it
4789  * will return -ENOSPC.
4790  */
4791 static int may_commit_transaction(struct btrfs_fs_info *fs_info,
4792                                   struct btrfs_space_info *space_info)
4793 {
4794         struct reserve_ticket *ticket = NULL;
4795         struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
4796         struct btrfs_trans_handle *trans;
4797         u64 bytes;
4798
4799         trans = (struct btrfs_trans_handle *)current->journal_info;
4800         if (trans)
4801                 return -EAGAIN;
4802
4803         spin_lock(&space_info->lock);
4804         if (!list_empty(&space_info->priority_tickets))
4805                 ticket = list_first_entry(&space_info->priority_tickets,
4806                                           struct reserve_ticket, list);
4807         else if (!list_empty(&space_info->tickets))
4808                 ticket = list_first_entry(&space_info->tickets,
4809                                           struct reserve_ticket, list);
4810         bytes = (ticket) ? ticket->bytes : 0;
4811         spin_unlock(&space_info->lock);
4812
4813         if (!bytes)
4814                 return 0;
4815
4816         /* See if there is enough pinned space to make this reservation */
4817         if (__percpu_counter_compare(&space_info->total_bytes_pinned,
4818                                    bytes,
4819                                    BTRFS_TOTAL_BYTES_PINNED_BATCH) >= 0)
4820                 goto commit;
4821
4822         /*
4823          * See if there is some space in the delayed insertion reservation for
4824          * this reservation.
4825          */
4826         if (space_info != delayed_rsv->space_info)
4827                 return -ENOSPC;
4828
4829         spin_lock(&delayed_rsv->lock);
4830         if (delayed_rsv->size > bytes)
4831                 bytes = 0;
4832         else
4833                 bytes -= delayed_rsv->size;
4834         spin_unlock(&delayed_rsv->lock);
4835
4836         if (__percpu_counter_compare(&space_info->total_bytes_pinned,
4837                                    bytes,
4838                                    BTRFS_TOTAL_BYTES_PINNED_BATCH) < 0) {
4839                 return -ENOSPC;
4840         }
4841
4842 commit:
4843         trans = btrfs_join_transaction(fs_info->extent_root);
4844         if (IS_ERR(trans))
4845                 return -ENOSPC;
4846
4847         return btrfs_commit_transaction(trans);
4848 }
4849
4850 /*
4851  * Try to flush some data based on policy set by @state. This is only advisory
4852  * and may fail for various reasons. The caller is supposed to examine the
4853  * state of @space_info to detect the outcome.
4854  */
4855 static void flush_space(struct btrfs_fs_info *fs_info,
4856                        struct btrfs_space_info *space_info, u64 num_bytes,
4857                        int state)
4858 {
4859         struct btrfs_root *root = fs_info->extent_root;
4860         struct btrfs_trans_handle *trans;
4861         int nr;
4862         int ret = 0;
4863
4864         switch (state) {
4865         case FLUSH_DELAYED_ITEMS_NR:
4866         case FLUSH_DELAYED_ITEMS:
4867                 if (state == FLUSH_DELAYED_ITEMS_NR)
4868                         nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
4869                 else
4870                         nr = -1;
4871
4872                 trans = btrfs_join_transaction(root);
4873                 if (IS_ERR(trans)) {
4874                         ret = PTR_ERR(trans);
4875                         break;
4876                 }
4877                 ret = btrfs_run_delayed_items_nr(trans, nr);
4878                 btrfs_end_transaction(trans);
4879                 break;
4880         case FLUSH_DELALLOC:
4881         case FLUSH_DELALLOC_WAIT:
4882                 shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
4883                                 state == FLUSH_DELALLOC_WAIT);
4884                 break;
4885         case ALLOC_CHUNK:
4886                 trans = btrfs_join_transaction(root);
4887                 if (IS_ERR(trans)) {
4888                         ret = PTR_ERR(trans);
4889                         break;
4890                 }
4891                 ret = do_chunk_alloc(trans,
4892                                      btrfs_metadata_alloc_profile(fs_info),
4893                                      CHUNK_ALLOC_NO_FORCE);
4894                 btrfs_end_transaction(trans);
4895                 if (ret > 0 || ret == -ENOSPC)
4896                         ret = 0;
4897                 break;
4898         case COMMIT_TRANS:
4899                 ret = may_commit_transaction(fs_info, space_info);
4900                 break;
4901         default:
4902                 ret = -ENOSPC;
4903                 break;
4904         }
4905
4906         trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
4907                                 ret);
4908         return;
4909 }
4910
4911 static inline u64
4912 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
4913                                  struct btrfs_space_info *space_info,
4914                                  bool system_chunk)
4915 {
4916         struct reserve_ticket *ticket;
4917         u64 used;
4918         u64 expected;
4919         u64 to_reclaim = 0;
4920
4921         list_for_each_entry(ticket, &space_info->tickets, list)
4922                 to_reclaim += ticket->bytes;
4923         list_for_each_entry(ticket, &space_info->priority_tickets, list)
4924                 to_reclaim += ticket->bytes;
4925         if (to_reclaim)
4926                 return to_reclaim;
4927
4928         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4929         if (can_overcommit(fs_info, space_info, to_reclaim,
4930                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
4931                 return 0;
4932
4933         used = btrfs_space_info_used(space_info, true);
4934
4935         if (can_overcommit(fs_info, space_info, SZ_1M,
4936                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
4937                 expected = div_factor_fine(space_info->total_bytes, 95);
4938         else
4939                 expected = div_factor_fine(space_info->total_bytes, 90);
4940
4941         if (used > expected)
4942                 to_reclaim = used - expected;
4943         else
4944                 to_reclaim = 0;
4945         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4946                                      space_info->bytes_reserved);
4947         return to_reclaim;
4948 }
4949
4950 static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
4951                                         struct btrfs_space_info *space_info,
4952                                         u64 used, bool system_chunk)
4953 {
4954         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4955
4956         /* If we're just plain full then async reclaim just slows us down. */
4957         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4958                 return 0;
4959
4960         if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info,
4961                                               system_chunk))
4962                 return 0;
4963
4964         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4965                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4966 }
4967
4968 static void wake_all_tickets(struct list_head *head)
4969 {
4970         struct reserve_ticket *ticket;
4971
4972         while (!list_empty(head)) {
4973                 ticket = list_first_entry(head, struct reserve_ticket, list);
4974                 list_del_init(&ticket->list);
4975                 ticket->error = -ENOSPC;
4976                 wake_up(&ticket->wait);
4977         }
4978 }
4979
4980 /*
4981  * This is for normal flushers, we can wait all goddamned day if we want to.  We
4982  * will loop and continuously try to flush as long as we are making progress.
4983  * We count progress as clearing off tickets each time we have to loop.
4984  */
4985 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4986 {
4987         struct btrfs_fs_info *fs_info;
4988         struct btrfs_space_info *space_info;
4989         u64 to_reclaim;
4990         int flush_state;
4991         int commit_cycles = 0;
4992         u64 last_tickets_id;
4993
4994         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4995         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4996
4997         spin_lock(&space_info->lock);
4998         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
4999                                                       false);
5000         if (!to_reclaim) {
5001                 space_info->flush = 0;
5002                 spin_unlock(&space_info->lock);
5003                 return;
5004         }
5005         last_tickets_id = space_info->tickets_id;
5006         spin_unlock(&space_info->lock);
5007
5008         flush_state = FLUSH_DELAYED_ITEMS_NR;
5009         do {
5010                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5011                 spin_lock(&space_info->lock);
5012                 if (list_empty(&space_info->tickets)) {
5013                         space_info->flush = 0;
5014                         spin_unlock(&space_info->lock);
5015                         return;
5016                 }
5017                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
5018                                                               space_info,
5019                                                               false);
5020                 if (last_tickets_id == space_info->tickets_id) {
5021                         flush_state++;
5022                 } else {
5023                         last_tickets_id = space_info->tickets_id;
5024                         flush_state = FLUSH_DELAYED_ITEMS_NR;
5025                         if (commit_cycles)
5026                                 commit_cycles--;
5027                 }
5028
5029                 if (flush_state > COMMIT_TRANS) {
5030                         commit_cycles++;
5031                         if (commit_cycles > 2) {
5032                                 wake_all_tickets(&space_info->tickets);
5033                                 space_info->flush = 0;
5034                         } else {
5035                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5036                         }
5037                 }
5038                 spin_unlock(&space_info->lock);
5039         } while (flush_state <= COMMIT_TRANS);
5040 }
5041
5042 void btrfs_init_async_reclaim_work(struct work_struct *work)
5043 {
5044         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5045 }
5046
5047 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5048                                             struct btrfs_space_info *space_info,
5049                                             struct reserve_ticket *ticket)
5050 {
5051         u64 to_reclaim;
5052         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5053
5054         spin_lock(&space_info->lock);
5055         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5056                                                       false);
5057         if (!to_reclaim) {
5058                 spin_unlock(&space_info->lock);
5059                 return;
5060         }
5061         spin_unlock(&space_info->lock);
5062
5063         do {
5064                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5065                 flush_state++;
5066                 spin_lock(&space_info->lock);
5067                 if (ticket->bytes == 0) {
5068                         spin_unlock(&space_info->lock);
5069                         return;
5070                 }
5071                 spin_unlock(&space_info->lock);
5072
5073                 /*
5074                  * Priority flushers can't wait on delalloc without
5075                  * deadlocking.
5076                  */
5077                 if (flush_state == FLUSH_DELALLOC ||
5078                     flush_state == FLUSH_DELALLOC_WAIT)
5079                         flush_state = ALLOC_CHUNK;
5080         } while (flush_state < COMMIT_TRANS);
5081 }
5082
5083 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5084                                struct btrfs_space_info *space_info,
5085                                struct reserve_ticket *ticket, u64 orig_bytes)
5086
5087 {
5088         DEFINE_WAIT(wait);
5089         int ret = 0;
5090
5091         spin_lock(&space_info->lock);
5092         while (ticket->bytes > 0 && ticket->error == 0) {
5093                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5094                 if (ret) {
5095                         ret = -EINTR;
5096                         break;
5097                 }
5098                 spin_unlock(&space_info->lock);
5099
5100                 schedule();
5101
5102                 finish_wait(&ticket->wait, &wait);
5103                 spin_lock(&space_info->lock);
5104         }
5105         if (!ret)
5106                 ret = ticket->error;
5107         if (!list_empty(&ticket->list))
5108                 list_del_init(&ticket->list);
5109         if (ticket->bytes && ticket->bytes < orig_bytes) {
5110                 u64 num_bytes = orig_bytes - ticket->bytes;
5111                 space_info->bytes_may_use -= num_bytes;
5112                 trace_btrfs_space_reservation(fs_info, "space_info",
5113                                               space_info->flags, num_bytes, 0);
5114         }
5115         spin_unlock(&space_info->lock);
5116
5117         return ret;
5118 }
5119
5120 /**
5121  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5122  * @root - the root we're allocating for
5123  * @space_info - the space info we want to allocate from
5124  * @orig_bytes - the number of bytes we want
5125  * @flush - whether or not we can flush to make our reservation
5126  *
5127  * This will reserve orig_bytes number of bytes from the space info associated
5128  * with the block_rsv.  If there is not enough space it will make an attempt to
5129  * flush out space to make room.  It will do this by flushing delalloc if
5130  * possible or committing the transaction.  If flush is 0 then no attempts to
5131  * regain reservations will be made and this will fail if there is not enough
5132  * space already.
5133  */
5134 static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
5135                                     struct btrfs_space_info *space_info,
5136                                     u64 orig_bytes,
5137                                     enum btrfs_reserve_flush_enum flush,
5138                                     bool system_chunk)
5139 {
5140         struct reserve_ticket ticket;
5141         u64 used;
5142         int ret = 0;
5143
5144         ASSERT(orig_bytes);
5145         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5146
5147         spin_lock(&space_info->lock);
5148         ret = -ENOSPC;
5149         used = btrfs_space_info_used(space_info, true);
5150
5151         /*
5152          * If we have enough space then hooray, make our reservation and carry
5153          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5154          * If not things get more complicated.
5155          */
5156         if (used + orig_bytes <= space_info->total_bytes) {
5157                 space_info->bytes_may_use += orig_bytes;
5158                 trace_btrfs_space_reservation(fs_info, "space_info",
5159                                               space_info->flags, orig_bytes, 1);
5160                 ret = 0;
5161         } else if (can_overcommit(fs_info, space_info, orig_bytes, flush,
5162                                   system_chunk)) {
5163                 space_info->bytes_may_use += orig_bytes;
5164                 trace_btrfs_space_reservation(fs_info, "space_info",
5165                                               space_info->flags, orig_bytes, 1);
5166                 ret = 0;
5167         }
5168
5169         /*
5170          * If we couldn't make a reservation then setup our reservation ticket
5171          * and kick the async worker if it's not already running.
5172          *
5173          * If we are a priority flusher then we just need to add our ticket to
5174          * the list and we will do our own flushing further down.
5175          */
5176         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5177                 ticket.bytes = orig_bytes;
5178                 ticket.error = 0;
5179                 init_waitqueue_head(&ticket.wait);
5180                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5181                         list_add_tail(&ticket.list, &space_info->tickets);
5182                         if (!space_info->flush) {
5183                                 space_info->flush = 1;
5184                                 trace_btrfs_trigger_flush(fs_info,
5185                                                           space_info->flags,
5186                                                           orig_bytes, flush,
5187                                                           "enospc");
5188                                 queue_work(system_unbound_wq,
5189                                            &fs_info->async_reclaim_work);
5190                         }
5191                 } else {
5192                         list_add_tail(&ticket.list,
5193                                       &space_info->priority_tickets);
5194                 }
5195         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5196                 used += orig_bytes;
5197                 /*
5198                  * We will do the space reservation dance during log replay,
5199                  * which means we won't have fs_info->fs_root set, so don't do
5200                  * the async reclaim as we will panic.
5201                  */
5202                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
5203                     need_do_async_reclaim(fs_info, space_info,
5204                                           used, system_chunk) &&
5205                     !work_busy(&fs_info->async_reclaim_work)) {
5206                         trace_btrfs_trigger_flush(fs_info, space_info->flags,
5207                                                   orig_bytes, flush, "preempt");
5208                         queue_work(system_unbound_wq,
5209                                    &fs_info->async_reclaim_work);
5210                 }
5211         }
5212         spin_unlock(&space_info->lock);
5213         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5214                 return ret;
5215
5216         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5217                 return wait_reserve_ticket(fs_info, space_info, &ticket,
5218                                            orig_bytes);
5219
5220         ret = 0;
5221         priority_reclaim_metadata_space(fs_info, space_info, &ticket);
5222         spin_lock(&space_info->lock);
5223         if (ticket.bytes) {
5224                 if (ticket.bytes < orig_bytes) {
5225                         u64 num_bytes = orig_bytes - ticket.bytes;
5226                         space_info->bytes_may_use -= num_bytes;
5227                         trace_btrfs_space_reservation(fs_info, "space_info",
5228                                                       space_info->flags,
5229                                                       num_bytes, 0);
5230
5231                 }
5232                 list_del_init(&ticket.list);
5233                 ret = -ENOSPC;
5234         }
5235         spin_unlock(&space_info->lock);
5236         ASSERT(list_empty(&ticket.list));
5237         return ret;
5238 }
5239
5240 /**
5241  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5242  * @root - the root we're allocating for
5243  * @block_rsv - the block_rsv we're allocating for
5244  * @orig_bytes - the number of bytes we want
5245  * @flush - whether or not we can flush to make our reservation
5246  *
5247  * This will reserve orgi_bytes number of bytes from the space info associated
5248  * with the block_rsv.  If there is not enough space it will make an attempt to
5249  * flush out space to make room.  It will do this by flushing delalloc if
5250  * possible or committing the transaction.  If flush is 0 then no attempts to
5251  * regain reservations will be made and this will fail if there is not enough
5252  * space already.
5253  */
5254 static int reserve_metadata_bytes(struct btrfs_root *root,
5255                                   struct btrfs_block_rsv *block_rsv,
5256                                   u64 orig_bytes,
5257                                   enum btrfs_reserve_flush_enum flush)
5258 {
5259         struct btrfs_fs_info *fs_info = root->fs_info;
5260         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5261         int ret;
5262         bool system_chunk = (root == fs_info->chunk_root);
5263
5264         ret = __reserve_metadata_bytes(fs_info, block_rsv->space_info,
5265                                        orig_bytes, flush, system_chunk);
5266         if (ret == -ENOSPC &&
5267             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5268                 if (block_rsv != global_rsv &&
5269                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5270                         ret = 0;
5271         }
5272         if (ret == -ENOSPC) {
5273                 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
5274                                               block_rsv->space_info->flags,
5275                                               orig_bytes, 1);
5276
5277                 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
5278                         dump_space_info(fs_info, block_rsv->space_info,
5279                                         orig_bytes, 0);
5280         }
5281         return ret;
5282 }
5283
5284 static struct btrfs_block_rsv *get_block_rsv(
5285                                         const struct btrfs_trans_handle *trans,
5286                                         const struct btrfs_root *root)
5287 {
5288         struct btrfs_fs_info *fs_info = root->fs_info;
5289         struct btrfs_block_rsv *block_rsv = NULL;
5290
5291         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5292             (root == fs_info->csum_root && trans->adding_csums) ||
5293             (root == fs_info->uuid_root))
5294                 block_rsv = trans->block_rsv;
5295
5296         if (!block_rsv)
5297                 block_rsv = root->block_rsv;
5298
5299         if (!block_rsv)
5300                 block_rsv = &fs_info->empty_block_rsv;
5301
5302         return block_rsv;
5303 }
5304
5305 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5306                                u64 num_bytes)
5307 {
5308         int ret = -ENOSPC;
5309         spin_lock(&block_rsv->lock);
5310         if (block_rsv->reserved >= num_bytes) {
5311                 block_rsv->reserved -= num_bytes;
5312                 if (block_rsv->reserved < block_rsv->size)
5313                         block_rsv->full = 0;
5314                 ret = 0;
5315         }
5316         spin_unlock(&block_rsv->lock);
5317         return ret;
5318 }
5319
5320 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5321                                 u64 num_bytes, bool update_size)
5322 {
5323         spin_lock(&block_rsv->lock);
5324         block_rsv->reserved += num_bytes;
5325         if (update_size)
5326                 block_rsv->size += num_bytes;
5327         else if (block_rsv->reserved >= block_rsv->size)
5328                 block_rsv->full = 1;
5329         spin_unlock(&block_rsv->lock);
5330 }
5331
5332 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5333                              struct btrfs_block_rsv *dest, u64 num_bytes,
5334                              int min_factor)
5335 {
5336         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5337         u64 min_bytes;
5338
5339         if (global_rsv->space_info != dest->space_info)
5340                 return -ENOSPC;
5341
5342         spin_lock(&global_rsv->lock);
5343         min_bytes = div_factor(global_rsv->size, min_factor);
5344         if (global_rsv->reserved < min_bytes + num_bytes) {
5345                 spin_unlock(&global_rsv->lock);
5346                 return -ENOSPC;
5347         }
5348         global_rsv->reserved -= num_bytes;
5349         if (global_rsv->reserved < global_rsv->size)
5350                 global_rsv->full = 0;
5351         spin_unlock(&global_rsv->lock);
5352
5353         block_rsv_add_bytes(dest, num_bytes, true);
5354         return 0;
5355 }
5356
5357 /*
5358  * This is for space we already have accounted in space_info->bytes_may_use, so
5359  * basically when we're returning space from block_rsv's.
5360  */
5361 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5362                                      struct btrfs_space_info *space_info,
5363                                      u64 num_bytes)
5364 {
5365         struct reserve_ticket *ticket;
5366         struct list_head *head;
5367         u64 used;
5368         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5369         bool check_overcommit = false;
5370
5371         spin_lock(&space_info->lock);
5372         head = &space_info->priority_tickets;
5373
5374         /*
5375          * If we are over our limit then we need to check and see if we can
5376          * overcommit, and if we can't then we just need to free up our space
5377          * and not satisfy any requests.
5378          */
5379         used = btrfs_space_info_used(space_info, true);
5380         if (used - num_bytes >= space_info->total_bytes)
5381                 check_overcommit = true;
5382 again:
5383         while (!list_empty(head) && num_bytes) {
5384                 ticket = list_first_entry(head, struct reserve_ticket,
5385                                           list);
5386                 /*
5387                  * We use 0 bytes because this space is already reserved, so
5388                  * adding the ticket space would be a double count.
5389                  */
5390                 if (check_overcommit &&
5391                     !can_overcommit(fs_info, space_info, 0, flush, false))
5392                         break;
5393                 if (num_bytes >= ticket->bytes) {
5394                         list_del_init(&ticket->list);
5395                         num_bytes -= ticket->bytes;
5396                         ticket->bytes = 0;
5397                         space_info->tickets_id++;
5398                         wake_up(&ticket->wait);
5399                 } else {
5400                         ticket->bytes -= num_bytes;
5401                         num_bytes = 0;
5402                 }
5403         }
5404
5405         if (num_bytes && head == &space_info->priority_tickets) {
5406                 head = &space_info->tickets;
5407                 flush = BTRFS_RESERVE_FLUSH_ALL;
5408                 goto again;
5409         }
5410         space_info->bytes_may_use -= num_bytes;
5411         trace_btrfs_space_reservation(fs_info, "space_info",
5412                                       space_info->flags, num_bytes, 0);
5413         spin_unlock(&space_info->lock);
5414 }
5415
5416 /*
5417  * This is for newly allocated space that isn't accounted in
5418  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5419  * we use this helper.
5420  */
5421 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5422                                      struct btrfs_space_info *space_info,
5423                                      u64 num_bytes)
5424 {
5425         struct reserve_ticket *ticket;
5426         struct list_head *head = &space_info->priority_tickets;
5427
5428 again:
5429         while (!list_empty(head) && num_bytes) {
5430                 ticket = list_first_entry(head, struct reserve_ticket,
5431                                           list);
5432                 if (num_bytes >= ticket->bytes) {
5433                         trace_btrfs_space_reservation(fs_info, "space_info",
5434                                                       space_info->flags,
5435                                                       ticket->bytes, 1);
5436                         list_del_init(&ticket->list);
5437                         num_bytes -= ticket->bytes;
5438                         space_info->bytes_may_use += ticket->bytes;
5439                         ticket->bytes = 0;
5440                         space_info->tickets_id++;
5441                         wake_up(&ticket->wait);
5442                 } else {
5443                         trace_btrfs_space_reservation(fs_info, "space_info",
5444                                                       space_info->flags,
5445                                                       num_bytes, 1);
5446                         space_info->bytes_may_use += num_bytes;
5447                         ticket->bytes -= num_bytes;
5448                         num_bytes = 0;
5449                 }
5450         }
5451
5452         if (num_bytes && head == &space_info->priority_tickets) {
5453                 head = &space_info->tickets;
5454                 goto again;
5455         }
5456 }
5457
5458 static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5459                                     struct btrfs_block_rsv *block_rsv,
5460                                     struct btrfs_block_rsv *dest, u64 num_bytes,
5461                                     u64 *qgroup_to_release_ret)
5462 {
5463         struct btrfs_space_info *space_info = block_rsv->space_info;
5464         u64 qgroup_to_release = 0;
5465         u64 ret;
5466
5467         spin_lock(&block_rsv->lock);
5468         if (num_bytes == (u64)-1) {
5469                 num_bytes = block_rsv->size;
5470                 qgroup_to_release = block_rsv->qgroup_rsv_size;
5471         }
5472         block_rsv->size -= num_bytes;
5473         if (block_rsv->reserved >= block_rsv->size) {
5474                 num_bytes = block_rsv->reserved - block_rsv->size;
5475                 block_rsv->reserved = block_rsv->size;
5476                 block_rsv->full = 1;
5477         } else {
5478                 num_bytes = 0;
5479         }
5480         if (block_rsv->qgroup_rsv_reserved >= block_rsv->qgroup_rsv_size) {
5481                 qgroup_to_release = block_rsv->qgroup_rsv_reserved -
5482                                     block_rsv->qgroup_rsv_size;
5483                 block_rsv->qgroup_rsv_reserved = block_rsv->qgroup_rsv_size;
5484         } else {
5485                 qgroup_to_release = 0;
5486         }
5487         spin_unlock(&block_rsv->lock);
5488
5489         ret = num_bytes;
5490         if (num_bytes > 0) {
5491                 if (dest) {
5492                         spin_lock(&dest->lock);
5493                         if (!dest->full) {
5494                                 u64 bytes_to_add;
5495
5496                                 bytes_to_add = dest->size - dest->reserved;
5497                                 bytes_to_add = min(num_bytes, bytes_to_add);
5498                                 dest->reserved += bytes_to_add;
5499                                 if (dest->reserved >= dest->size)
5500                                         dest->full = 1;
5501                                 num_bytes -= bytes_to_add;
5502                         }
5503                         spin_unlock(&dest->lock);
5504                 }
5505                 if (num_bytes)
5506                         space_info_add_old_bytes(fs_info, space_info,
5507                                                  num_bytes);
5508         }
5509         if (qgroup_to_release_ret)
5510                 *qgroup_to_release_ret = qgroup_to_release;
5511         return ret;
5512 }
5513
5514 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5515                             struct btrfs_block_rsv *dst, u64 num_bytes,
5516                             bool update_size)
5517 {
5518         int ret;
5519
5520         ret = block_rsv_use_bytes(src, num_bytes);
5521         if (ret)
5522                 return ret;
5523
5524         block_rsv_add_bytes(dst, num_bytes, update_size);
5525         return 0;
5526 }
5527
5528 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5529 {
5530         memset(rsv, 0, sizeof(*rsv));
5531         spin_lock_init(&rsv->lock);
5532         rsv->type = type;
5533 }
5534
5535 void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,
5536                                    struct btrfs_block_rsv *rsv,
5537                                    unsigned short type)
5538 {
5539         btrfs_init_block_rsv(rsv, type);
5540         rsv->space_info = __find_space_info(fs_info,
5541                                             BTRFS_BLOCK_GROUP_METADATA);
5542 }
5543
5544 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
5545                                               unsigned short type)
5546 {
5547         struct btrfs_block_rsv *block_rsv;
5548
5549         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5550         if (!block_rsv)
5551                 return NULL;
5552
5553         btrfs_init_metadata_block_rsv(fs_info, block_rsv, type);
5554         return block_rsv;
5555 }
5556
5557 void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
5558                           struct btrfs_block_rsv *rsv)
5559 {
5560         if (!rsv)
5561                 return;
5562         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5563         kfree(rsv);
5564 }
5565
5566 int btrfs_block_rsv_add(struct btrfs_root *root,
5567                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5568                         enum btrfs_reserve_flush_enum flush)
5569 {
5570         int ret;
5571
5572         if (num_bytes == 0)
5573                 return 0;
5574
5575         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5576         if (!ret)
5577                 block_rsv_add_bytes(block_rsv, num_bytes, true);
5578
5579         return ret;
5580 }
5581
5582 int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
5583 {
5584         u64 num_bytes = 0;
5585         int ret = -ENOSPC;
5586
5587         if (!block_rsv)
5588                 return 0;
5589
5590         spin_lock(&block_rsv->lock);
5591         num_bytes = div_factor(block_rsv->size, min_factor);
5592         if (block_rsv->reserved >= num_bytes)
5593                 ret = 0;
5594         spin_unlock(&block_rsv->lock);
5595
5596         return ret;
5597 }
5598
5599 int btrfs_block_rsv_refill(struct btrfs_root *root,
5600                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5601                            enum btrfs_reserve_flush_enum flush)
5602 {
5603         u64 num_bytes = 0;
5604         int ret = -ENOSPC;
5605
5606         if (!block_rsv)
5607                 return 0;
5608
5609         spin_lock(&block_rsv->lock);
5610         num_bytes = min_reserved;
5611         if (block_rsv->reserved >= num_bytes)
5612                 ret = 0;
5613         else
5614                 num_bytes -= block_rsv->reserved;
5615         spin_unlock(&block_rsv->lock);
5616
5617         if (!ret)
5618                 return 0;
5619
5620         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5621         if (!ret) {
5622                 block_rsv_add_bytes(block_rsv, num_bytes, false);
5623                 return 0;
5624         }
5625
5626         return ret;
5627 }
5628
5629 /**
5630  * btrfs_inode_rsv_refill - refill the inode block rsv.
5631  * @inode - the inode we are refilling.
5632  * @flush - the flusing restriction.
5633  *
5634  * Essentially the same as btrfs_block_rsv_refill, except it uses the
5635  * block_rsv->size as the minimum size.  We'll either refill the missing amount
5636  * or return if we already have enough space.  This will also handle the resreve
5637  * tracepoint for the reserved amount.
5638  */
5639 static int btrfs_inode_rsv_refill(struct btrfs_inode *inode,
5640                                   enum btrfs_reserve_flush_enum flush)
5641 {
5642         struct btrfs_root *root = inode->root;
5643         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5644         u64 num_bytes = 0;
5645         u64 qgroup_num_bytes = 0;
5646         int ret = -ENOSPC;
5647
5648         spin_lock(&block_rsv->lock);
5649         if (block_rsv->reserved < block_rsv->size)
5650                 num_bytes = block_rsv->size - block_rsv->reserved;
5651         if (block_rsv->qgroup_rsv_reserved < block_rsv->qgroup_rsv_size)
5652                 qgroup_num_bytes = block_rsv->qgroup_rsv_size -
5653                                    block_rsv->qgroup_rsv_reserved;
5654         spin_unlock(&block_rsv->lock);
5655
5656         if (num_bytes == 0)
5657                 return 0;
5658
5659         ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_num_bytes, true);
5660         if (ret)
5661                 return ret;
5662         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5663         if (!ret) {
5664                 block_rsv_add_bytes(block_rsv, num_bytes, false);
5665                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5666                                               btrfs_ino(inode), num_bytes, 1);
5667
5668                 /* Don't forget to increase qgroup_rsv_reserved */
5669                 spin_lock(&block_rsv->lock);
5670                 block_rsv->qgroup_rsv_reserved += qgroup_num_bytes;
5671                 spin_unlock(&block_rsv->lock);
5672         } else
5673                 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
5674         return ret;
5675 }
5676
5677 /**
5678  * btrfs_inode_rsv_release - release any excessive reservation.
5679  * @inode - the inode we need to release from.
5680  * @qgroup_free - free or convert qgroup meta.
5681  *   Unlike normal operation, qgroup meta reservation needs to know if we are
5682  *   freeing qgroup reservation or just converting it into per-trans.  Normally
5683  *   @qgroup_free is true for error handling, and false for normal release.
5684  *
5685  * This is the same as btrfs_block_rsv_release, except that it handles the
5686  * tracepoint for the reservation.
5687  */
5688 static void btrfs_inode_rsv_release(struct btrfs_inode *inode, bool qgroup_free)
5689 {
5690         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5691         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5692         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5693         u64 released = 0;
5694         u64 qgroup_to_release = 0;
5695
5696         /*
5697          * Since we statically set the block_rsv->size we just want to say we
5698          * are releasing 0 bytes, and then we'll just get the reservation over
5699          * the size free'd.
5700          */
5701         released = block_rsv_release_bytes(fs_info, block_rsv, global_rsv, 0,
5702                                            &qgroup_to_release);
5703         if (released > 0)
5704                 trace_btrfs_space_reservation(fs_info, "delalloc",
5705                                               btrfs_ino(inode), released, 0);
5706         if (qgroup_free)
5707                 btrfs_qgroup_free_meta_prealloc(inode->root, qgroup_to_release);
5708         else
5709                 btrfs_qgroup_convert_reserved_meta(inode->root,
5710                                                    qgroup_to_release);
5711 }
5712
5713 void btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
5714                              struct btrfs_block_rsv *block_rsv,
5715                              u64 num_bytes)
5716 {
5717         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5718
5719         if (global_rsv == block_rsv ||
5720             block_rsv->space_info != global_rsv->space_info)
5721                 global_rsv = NULL;
5722         block_rsv_release_bytes(fs_info, block_rsv, global_rsv, num_bytes, NULL);
5723 }
5724
5725 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5726 {
5727         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5728         struct btrfs_space_info *sinfo = block_rsv->space_info;
5729         u64 num_bytes;
5730
5731         /*
5732          * The global block rsv is based on the size of the extent tree, the
5733          * checksum tree and the root tree.  If the fs is empty we want to set
5734          * it to a minimal amount for safety.
5735          */
5736         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5737                 btrfs_root_used(&fs_info->csum_root->root_item) +
5738                 btrfs_root_used(&fs_info->tree_root->root_item);
5739         num_bytes = max_t(u64, num_bytes, SZ_16M);
5740
5741         spin_lock(&sinfo->lock);
5742         spin_lock(&block_rsv->lock);
5743
5744         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5745
5746         if (block_rsv->reserved < block_rsv->size) {
5747                 num_bytes = btrfs_space_info_used(sinfo, true);
5748                 if (sinfo->total_bytes > num_bytes) {
5749                         num_bytes = sinfo->total_bytes - num_bytes;
5750                         num_bytes = min(num_bytes,
5751                                         block_rsv->size - block_rsv->reserved);
5752                         block_rsv->reserved += num_bytes;
5753                         sinfo->bytes_may_use += num_bytes;
5754                         trace_btrfs_space_reservation(fs_info, "space_info",
5755                                                       sinfo->flags, num_bytes,
5756                                                       1);
5757                 }
5758         } else if (block_rsv->reserved > block_rsv->size) {
5759                 num_bytes = block_rsv->reserved - block_rsv->size;
5760                 sinfo->bytes_may_use -= num_bytes;
5761                 trace_btrfs_space_reservation(fs_info, "space_info",
5762                                       sinfo->flags, num_bytes, 0);
5763                 block_rsv->reserved = block_rsv->size;
5764         }
5765
5766         if (block_rsv->reserved == block_rsv->size)
5767                 block_rsv->full = 1;
5768         else
5769                 block_rsv->full = 0;
5770
5771         spin_unlock(&block_rsv->lock);
5772         spin_unlock(&sinfo->lock);
5773 }
5774
5775 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5776 {
5777         struct btrfs_space_info *space_info;
5778
5779         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5780         fs_info->chunk_block_rsv.space_info = space_info;
5781
5782         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5783         fs_info->global_block_rsv.space_info = space_info;
5784         fs_info->trans_block_rsv.space_info = space_info;
5785         fs_info->empty_block_rsv.space_info = space_info;
5786         fs_info->delayed_block_rsv.space_info = space_info;
5787
5788         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5789         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5790         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5791         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5792         if (fs_info->quota_root)
5793                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5794         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5795
5796         update_global_block_rsv(fs_info);
5797 }
5798
5799 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5800 {
5801         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5802                                 (u64)-1, NULL);
5803         WARN_ON(fs_info->trans_block_rsv.size > 0);
5804         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5805         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5806         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5807         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5808         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5809 }
5810
5811
5812 /*
5813  * To be called after all the new block groups attached to the transaction
5814  * handle have been created (btrfs_create_pending_block_groups()).
5815  */
5816 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5817 {
5818         struct btrfs_fs_info *fs_info = trans->fs_info;
5819
5820         if (!trans->chunk_bytes_reserved)
5821                 return;
5822
5823         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5824
5825         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5826                                 trans->chunk_bytes_reserved, NULL);
5827         trans->chunk_bytes_reserved = 0;
5828 }
5829
5830 /*
5831  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5832  * root: the root of the parent directory
5833  * rsv: block reservation
5834  * items: the number of items that we need do reservation
5835  * use_global_rsv: allow fallback to the global block reservation
5836  *
5837  * This function is used to reserve the space for snapshot/subvolume
5838  * creation and deletion. Those operations are different with the
5839  * common file/directory operations, they change two fs/file trees
5840  * and root tree, the number of items that the qgroup reserves is
5841  * different with the free space reservation. So we can not use
5842  * the space reservation mechanism in start_transaction().
5843  */
5844 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5845                                      struct btrfs_block_rsv *rsv, int items,
5846                                      bool use_global_rsv)
5847 {
5848         u64 qgroup_num_bytes = 0;
5849         u64 num_bytes;
5850         int ret;
5851         struct btrfs_fs_info *fs_info = root->fs_info;
5852         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5853
5854         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5855                 /* One for parent inode, two for dir entries */
5856                 qgroup_num_bytes = 3 * fs_info->nodesize;
5857                 ret = btrfs_qgroup_reserve_meta_prealloc(root,
5858                                 qgroup_num_bytes, true);
5859                 if (ret)
5860                         return ret;
5861         }
5862
5863         num_bytes = btrfs_calc_trans_metadata_size(fs_info, items);
5864         rsv->space_info = __find_space_info(fs_info,
5865                                             BTRFS_BLOCK_GROUP_METADATA);
5866         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5867                                   BTRFS_RESERVE_FLUSH_ALL);
5868
5869         if (ret == -ENOSPC && use_global_rsv)
5870                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true);
5871
5872         if (ret && qgroup_num_bytes)
5873                 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
5874
5875         return ret;
5876 }
5877
5878 void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
5879                                       struct btrfs_block_rsv *rsv)
5880 {
5881         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5882 }
5883
5884 static void btrfs_calculate_inode_block_rsv_size(struct btrfs_fs_info *fs_info,
5885                                                  struct btrfs_inode *inode)
5886 {
5887         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5888         u64 reserve_size = 0;
5889         u64 qgroup_rsv_size = 0;
5890         u64 csum_leaves;
5891         unsigned outstanding_extents;
5892
5893         lockdep_assert_held(&inode->lock);
5894         outstanding_extents = inode->outstanding_extents;
5895         if (outstanding_extents)
5896                 reserve_size = btrfs_calc_trans_metadata_size(fs_info,
5897                                                 outstanding_extents + 1);
5898         csum_leaves = btrfs_csum_bytes_to_leaves(fs_info,
5899                                                  inode->csum_bytes);
5900         reserve_size += btrfs_calc_trans_metadata_size(fs_info,
5901                                                        csum_leaves);
5902         /*
5903          * For qgroup rsv, the calculation is very simple:
5904          * account one nodesize for each outstanding extent
5905          *
5906          * This is overestimating in most cases.
5907          */
5908         qgroup_rsv_size = outstanding_extents * fs_info->nodesize;
5909
5910         spin_lock(&block_rsv->lock);
5911         block_rsv->size = reserve_size;
5912         block_rsv->qgroup_rsv_size = qgroup_rsv_size;
5913         spin_unlock(&block_rsv->lock);
5914 }
5915
5916 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
5917 {
5918         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5919         unsigned nr_extents;
5920         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5921         int ret = 0;
5922         bool delalloc_lock = true;
5923
5924         /* If we are a free space inode we need to not flush since we will be in
5925          * the middle of a transaction commit.  We also don't need the delalloc
5926          * mutex since we won't race with anybody.  We need this mostly to make
5927          * lockdep shut its filthy mouth.
5928          *
5929          * If we have a transaction open (can happen if we call truncate_block
5930          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5931          */
5932         if (btrfs_is_free_space_inode(inode)) {
5933                 flush = BTRFS_RESERVE_NO_FLUSH;
5934                 delalloc_lock = false;
5935         } else {
5936                 if (current->journal_info)
5937                         flush = BTRFS_RESERVE_FLUSH_LIMIT;
5938
5939                 if (btrfs_transaction_in_commit(fs_info))
5940                         schedule_timeout(1);
5941         }
5942
5943         if (delalloc_lock)
5944                 mutex_lock(&inode->delalloc_mutex);
5945
5946         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
5947
5948         /* Add our new extents and calculate the new rsv size. */
5949         spin_lock(&inode->lock);
5950         nr_extents = count_max_extents(num_bytes);
5951         btrfs_mod_outstanding_extents(inode, nr_extents);
5952         inode->csum_bytes += num_bytes;
5953         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5954         spin_unlock(&inode->lock);
5955
5956         ret = btrfs_inode_rsv_refill(inode, flush);
5957         if (unlikely(ret))
5958                 goto out_fail;
5959
5960         if (delalloc_lock)
5961                 mutex_unlock(&inode->delalloc_mutex);
5962         return 0;
5963
5964 out_fail:
5965         spin_lock(&inode->lock);
5966         nr_extents = count_max_extents(num_bytes);
5967         btrfs_mod_outstanding_extents(inode, -nr_extents);
5968         inode->csum_bytes -= num_bytes;
5969         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5970         spin_unlock(&inode->lock);
5971
5972         btrfs_inode_rsv_release(inode, true);
5973         if (delalloc_lock)
5974                 mutex_unlock(&inode->delalloc_mutex);
5975         return ret;
5976 }
5977
5978 /**
5979  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5980  * @inode: the inode to release the reservation for.
5981  * @num_bytes: the number of bytes we are releasing.
5982  * @qgroup_free: free qgroup reservation or convert it to per-trans reservation
5983  *
5984  * This will release the metadata reservation for an inode.  This can be called
5985  * once we complete IO for a given set of bytes to release their metadata
5986  * reservations, or on error for the same reason.
5987  */
5988 void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes,
5989                                      bool qgroup_free)
5990 {
5991         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5992
5993         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
5994         spin_lock(&inode->lock);
5995         inode->csum_bytes -= num_bytes;
5996         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5997         spin_unlock(&inode->lock);
5998
5999         if (btrfs_is_testing(fs_info))
6000                 return;
6001
6002         btrfs_inode_rsv_release(inode, qgroup_free);
6003 }
6004
6005 /**
6006  * btrfs_delalloc_release_extents - release our outstanding_extents
6007  * @inode: the inode to balance the reservation for.
6008  * @num_bytes: the number of bytes we originally reserved with
6009  * @qgroup_free: do we need to free qgroup meta reservation or convert them.
6010  *
6011  * When we reserve space we increase outstanding_extents for the extents we may
6012  * add.  Once we've set the range as delalloc or created our ordered extents we
6013  * have outstanding_extents to track the real usage, so we use this to free our
6014  * temporarily tracked outstanding_extents.  This _must_ be used in conjunction
6015  * with btrfs_delalloc_reserve_metadata.
6016  */
6017 void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes,
6018                                     bool qgroup_free)
6019 {
6020         struct btrfs_fs_info *fs_info = inode->root->fs_info;
6021         unsigned num_extents;
6022
6023         spin_lock(&inode->lock);
6024         num_extents = count_max_extents(num_bytes);
6025         btrfs_mod_outstanding_extents(inode, -num_extents);
6026         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6027         spin_unlock(&inode->lock);
6028
6029         if (btrfs_is_testing(fs_info))
6030                 return;
6031
6032         btrfs_inode_rsv_release(inode, qgroup_free);
6033 }
6034
6035 /**
6036  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6037  * delalloc
6038  * @inode: inode we're writing to
6039  * @start: start range we are writing to
6040  * @len: how long the range we are writing to
6041  * @reserved: mandatory parameter, record actually reserved qgroup ranges of
6042  *            current reservation.
6043  *
6044  * This will do the following things
6045  *
6046  * o reserve space in data space info for num bytes
6047  *   and reserve precious corresponding qgroup space
6048  *   (Done in check_data_free_space)
6049  *
6050  * o reserve space for metadata space, based on the number of outstanding
6051  *   extents and how much csums will be needed
6052  *   also reserve metadata space in a per root over-reserve method.
6053  * o add to the inodes->delalloc_bytes
6054  * o add it to the fs_info's delalloc inodes list.
6055  *   (Above 3 all done in delalloc_reserve_metadata)
6056  *
6057  * Return 0 for success
6058  * Return <0 for error(-ENOSPC or -EQUOT)
6059  */
6060 int btrfs_delalloc_reserve_space(struct inode *inode,
6061                         struct extent_changeset **reserved, u64 start, u64 len)
6062 {
6063         int ret;
6064
6065         ret = btrfs_check_data_free_space(inode, reserved, start, len);
6066         if (ret < 0)
6067                 return ret;
6068         ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);
6069         if (ret < 0)
6070                 btrfs_free_reserved_data_space(inode, *reserved, start, len);
6071         return ret;
6072 }
6073
6074 /**
6075  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6076  * @inode: inode we're releasing space for
6077  * @start: start position of the space already reserved
6078  * @len: the len of the space already reserved
6079  * @release_bytes: the len of the space we consumed or didn't use
6080  *
6081  * This function will release the metadata space that was not used and will
6082  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6083  * list if there are no delalloc bytes left.
6084  * Also it will handle the qgroup reserved space.
6085  */
6086 void btrfs_delalloc_release_space(struct inode *inode,
6087                                   struct extent_changeset *reserved,
6088                                   u64 start, u64 len, bool qgroup_free)
6089 {
6090         btrfs_delalloc_release_metadata(BTRFS_I(inode), len, qgroup_free);
6091         btrfs_free_reserved_data_space(inode, reserved, start, len);
6092 }
6093
6094 static int update_block_group(struct btrfs_trans_handle *trans,
6095                               struct btrfs_fs_info *info, u64 bytenr,
6096                               u64 num_bytes, int alloc)
6097 {
6098         struct btrfs_block_group_cache *cache = NULL;
6099         u64 total = num_bytes;
6100         u64 old_val;
6101         u64 byte_in_group;
6102         int factor;
6103
6104         /* block accounting for super block */
6105         spin_lock(&info->delalloc_root_lock);
6106         old_val = btrfs_super_bytes_used(info->super_copy);
6107         if (alloc)
6108                 old_val += num_bytes;
6109         else
6110                 old_val -= num_bytes;
6111         btrfs_set_super_bytes_used(info->super_copy, old_val);
6112         spin_unlock(&info->delalloc_root_lock);
6113
6114         while (total) {
6115                 cache = btrfs_lookup_block_group(info, bytenr);
6116                 if (!cache)
6117                         return -ENOENT;
6118                 factor = btrfs_bg_type_to_factor(cache->flags);
6119
6120                 /*
6121                  * If this block group has free space cache written out, we
6122                  * need to make sure to load it if we are removing space.  This
6123                  * is because we need the unpinning stage to actually add the
6124                  * space back to the block group, otherwise we will leak space.
6125                  */
6126                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6127                         cache_block_group(cache, 1);
6128
6129                 byte_in_group = bytenr - cache->key.objectid;
6130                 WARN_ON(byte_in_group > cache->key.offset);
6131
6132                 spin_lock(&cache->space_info->lock);
6133                 spin_lock(&cache->lock);
6134
6135                 if (btrfs_test_opt(info, SPACE_CACHE) &&
6136                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6137                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6138
6139                 old_val = btrfs_block_group_used(&cache->item);
6140                 num_bytes = min(total, cache->key.offset - byte_in_group);
6141                 if (alloc) {
6142                         old_val += num_bytes;
6143                         btrfs_set_block_group_used(&cache->item, old_val);
6144                         cache->reserved -= num_bytes;
6145                         cache->space_info->bytes_reserved -= num_bytes;
6146                         cache->space_info->bytes_used += num_bytes;
6147                         cache->space_info->disk_used += num_bytes * factor;
6148                         spin_unlock(&cache->lock);
6149                         spin_unlock(&cache->space_info->lock);
6150                 } else {
6151                         old_val -= num_bytes;
6152                         btrfs_set_block_group_used(&cache->item, old_val);
6153                         cache->pinned += num_bytes;
6154                         cache->space_info->bytes_pinned += num_bytes;
6155                         cache->space_info->bytes_used -= num_bytes;
6156                         cache->space_info->disk_used -= num_bytes * factor;
6157                         spin_unlock(&cache->lock);
6158                         spin_unlock(&cache->space_info->lock);
6159
6160                         trace_btrfs_space_reservation(info, "pinned",
6161                                                       cache->space_info->flags,
6162                                                       num_bytes, 1);
6163                         percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
6164                                            num_bytes,
6165                                            BTRFS_TOTAL_BYTES_PINNED_BATCH);
6166                         set_extent_dirty(info->pinned_extents,
6167                                          bytenr, bytenr + num_bytes - 1,
6168                                          GFP_NOFS | __GFP_NOFAIL);
6169                 }
6170
6171                 spin_lock(&trans->transaction->dirty_bgs_lock);
6172                 if (list_empty(&cache->dirty_list)) {
6173                         list_add_tail(&cache->dirty_list,
6174                                       &trans->transaction->dirty_bgs);
6175                         trans->transaction->num_dirty_bgs++;
6176                         btrfs_get_block_group(cache);
6177                 }
6178                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6179
6180                 /*
6181                  * No longer have used bytes in this block group, queue it for
6182                  * deletion. We do this after adding the block group to the
6183                  * dirty list to avoid races between cleaner kthread and space
6184                  * cache writeout.
6185                  */
6186                 if (!alloc && old_val == 0)
6187                         btrfs_mark_bg_unused(cache);
6188
6189                 btrfs_put_block_group(cache);
6190                 total -= num_bytes;
6191                 bytenr += num_bytes;
6192         }
6193         return 0;
6194 }
6195
6196 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
6197 {
6198         struct btrfs_block_group_cache *cache;
6199         u64 bytenr;
6200
6201         spin_lock(&fs_info->block_group_cache_lock);
6202         bytenr = fs_info->first_logical_byte;
6203         spin_unlock(&fs_info->block_group_cache_lock);
6204
6205         if (bytenr < (u64)-1)
6206                 return bytenr;
6207
6208         cache = btrfs_lookup_first_block_group(fs_info, search_start);
6209         if (!cache)
6210                 return 0;
6211
6212         bytenr = cache->key.objectid;
6213         btrfs_put_block_group(cache);
6214
6215         return bytenr;
6216 }
6217
6218 static int pin_down_extent(struct btrfs_fs_info *fs_info,
6219                            struct btrfs_block_group_cache *cache,
6220                            u64 bytenr, u64 num_bytes, int reserved)
6221 {
6222         spin_lock(&cache->space_info->lock);
6223         spin_lock(&cache->lock);
6224         cache->pinned += num_bytes;
6225         cache->space_info->bytes_pinned += num_bytes;
6226         if (reserved) {
6227                 cache->reserved -= num_bytes;
6228                 cache->space_info->bytes_reserved -= num_bytes;
6229         }
6230         spin_unlock(&cache->lock);
6231         spin_unlock(&cache->space_info->lock);
6232
6233         trace_btrfs_space_reservation(fs_info, "pinned",
6234                                       cache->space_info->flags, num_bytes, 1);
6235         percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
6236                     num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
6237         set_extent_dirty(fs_info->pinned_extents, bytenr,
6238                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6239         return 0;
6240 }
6241
6242 /*
6243  * this function must be called within transaction
6244  */
6245 int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
6246                      u64 bytenr, u64 num_bytes, int reserved)
6247 {
6248         struct btrfs_block_group_cache *cache;
6249
6250         cache = btrfs_lookup_block_group(fs_info, bytenr);
6251         BUG_ON(!cache); /* Logic error */
6252
6253         pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
6254
6255         btrfs_put_block_group(cache);
6256         return 0;
6257 }
6258
6259 /*
6260  * this function must be called within transaction
6261  */
6262 int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
6263                                     u64 bytenr, u64 num_bytes)
6264 {
6265         struct btrfs_block_group_cache *cache;
6266         int ret;
6267
6268         cache = btrfs_lookup_block_group(fs_info, bytenr);
6269         if (!cache)
6270                 return -EINVAL;
6271
6272         /*
6273          * pull in the free space cache (if any) so that our pin
6274          * removes the free space from the cache.  We have load_only set
6275          * to one because the slow code to read in the free extents does check
6276          * the pinned extents.
6277          */
6278         cache_block_group(cache, 1);
6279
6280         pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
6281
6282         /* remove us from the free space cache (if we're there at all) */
6283         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6284         btrfs_put_block_group(cache);
6285         return ret;
6286 }
6287
6288 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
6289                                    u64 start, u64 num_bytes)
6290 {
6291         int ret;
6292         struct btrfs_block_group_cache *block_group;
6293         struct btrfs_caching_control *caching_ctl;
6294
6295         block_group = btrfs_lookup_block_group(fs_info, start);
6296         if (!block_group)
6297                 return -EINVAL;
6298
6299         cache_block_group(block_group, 0);
6300         caching_ctl = get_caching_control(block_group);
6301
6302         if (!caching_ctl) {
6303                 /* Logic error */
6304                 BUG_ON(!block_group_cache_done(block_group));
6305                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6306         } else {
6307                 mutex_lock(&caching_ctl->mutex);
6308
6309                 if (start >= caching_ctl->progress) {
6310                         ret = add_excluded_extent(fs_info, start, num_bytes);
6311                 } else if (start + num_bytes <= caching_ctl->progress) {
6312                         ret = btrfs_remove_free_space(block_group,
6313                                                       start, num_bytes);
6314                 } else {
6315                         num_bytes = caching_ctl->progress - start;
6316                         ret = btrfs_remove_free_space(block_group,
6317                                                       start, num_bytes);
6318                         if (ret)
6319                                 goto out_lock;
6320
6321                         num_bytes = (start + num_bytes) -
6322                                 caching_ctl->progress;
6323                         start = caching_ctl->progress;
6324                         ret = add_excluded_extent(fs_info, start, num_bytes);
6325                 }
6326 out_lock:
6327                 mutex_unlock(&caching_ctl->mutex);
6328                 put_caching_control(caching_ctl);
6329         }
6330         btrfs_put_block_group(block_group);
6331         return ret;
6332 }
6333
6334 int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
6335                                  struct extent_buffer *eb)
6336 {
6337         struct btrfs_file_extent_item *item;
6338         struct btrfs_key key;
6339         int found_type;
6340         int i;
6341         int ret = 0;
6342
6343         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
6344                 return 0;
6345
6346         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6347                 btrfs_item_key_to_cpu(eb, &key, i);
6348                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6349                         continue;
6350                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6351                 found_type = btrfs_file_extent_type(eb, item);
6352                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6353                         continue;
6354                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6355                         continue;
6356                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6357                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6358                 ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
6359                 if (ret)
6360                         break;
6361         }
6362
6363         return ret;
6364 }
6365
6366 static void
6367 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6368 {
6369         atomic_inc(&bg->reservations);
6370 }
6371
6372 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6373                                         const u64 start)
6374 {
6375         struct btrfs_block_group_cache *bg;
6376
6377         bg = btrfs_lookup_block_group(fs_info, start);
6378         ASSERT(bg);
6379         if (atomic_dec_and_test(&bg->reservations))
6380                 wake_up_var(&bg->reservations);
6381         btrfs_put_block_group(bg);
6382 }
6383
6384 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6385 {
6386         struct btrfs_space_info *space_info = bg->space_info;
6387
6388         ASSERT(bg->ro);
6389
6390         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6391                 return;
6392
6393         /*
6394          * Our block group is read only but before we set it to read only,
6395          * some task might have had allocated an extent from it already, but it
6396          * has not yet created a respective ordered extent (and added it to a
6397          * root's list of ordered extents).
6398          * Therefore wait for any task currently allocating extents, since the
6399          * block group's reservations counter is incremented while a read lock
6400          * on the groups' semaphore is held and decremented after releasing
6401          * the read access on that semaphore and creating the ordered extent.
6402          */
6403         down_write(&space_info->groups_sem);
6404         up_write(&space_info->groups_sem);
6405
6406         wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
6407 }
6408
6409 /**
6410  * btrfs_add_reserved_bytes - update the block_group and space info counters
6411  * @cache:      The cache we are manipulating
6412  * @ram_bytes:  The number of bytes of file content, and will be same to
6413  *              @num_bytes except for the compress path.
6414  * @num_bytes:  The number of bytes in question
6415  * @delalloc:   The blocks are allocated for the delalloc write
6416  *
6417  * This is called by the allocator when it reserves space. If this is a
6418  * reservation and the block group has become read only we cannot make the
6419  * reservation and return -EAGAIN, otherwise this function always succeeds.
6420  */
6421 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6422                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6423 {
6424         struct btrfs_space_info *space_info = cache->space_info;
6425         int ret = 0;
6426
6427         spin_lock(&space_info->lock);
6428         spin_lock(&cache->lock);
6429         if (cache->ro) {
6430                 ret = -EAGAIN;
6431         } else {
6432                 cache->reserved += num_bytes;
6433                 space_info->bytes_reserved += num_bytes;
6434                 space_info->bytes_may_use -= ram_bytes;
6435                 if (delalloc)
6436                         cache->delalloc_bytes += num_bytes;
6437         }
6438         spin_unlock(&cache->lock);
6439         spin_unlock(&space_info->lock);
6440         return ret;
6441 }
6442
6443 /**
6444  * btrfs_free_reserved_bytes - update the block_group and space info counters
6445  * @cache:      The cache we are manipulating
6446  * @num_bytes:  The number of bytes in question
6447  * @delalloc:   The blocks are allocated for the delalloc write
6448  *
6449  * This is called by somebody who is freeing space that was never actually used
6450  * on disk.  For example if you reserve some space for a new leaf in transaction
6451  * A and before transaction A commits you free that leaf, you call this with
6452  * reserve set to 0 in order to clear the reservation.
6453  */
6454
6455 static void btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6456                                       u64 num_bytes, int delalloc)
6457 {
6458         struct btrfs_space_info *space_info = cache->space_info;
6459
6460         spin_lock(&space_info->lock);
6461         spin_lock(&cache->lock);
6462         if (cache->ro)
6463                 space_info->bytes_readonly += num_bytes;
6464         cache->reserved -= num_bytes;
6465         space_info->bytes_reserved -= num_bytes;
6466         space_info->max_extent_size = 0;
6467
6468         if (delalloc)
6469                 cache->delalloc_bytes -= num_bytes;
6470         spin_unlock(&cache->lock);
6471         spin_unlock(&space_info->lock);
6472 }
6473 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
6474 {
6475         struct btrfs_caching_control *next;
6476         struct btrfs_caching_control *caching_ctl;
6477         struct btrfs_block_group_cache *cache;
6478
6479         down_write(&fs_info->commit_root_sem);
6480
6481         list_for_each_entry_safe(caching_ctl, next,
6482                                  &fs_info->caching_block_groups, list) {
6483                 cache = caching_ctl->block_group;
6484                 if (block_group_cache_done(cache)) {
6485                         cache->last_byte_to_unpin = (u64)-1;
6486                         list_del_init(&caching_ctl->list);
6487                         put_caching_control(caching_ctl);
6488                 } else {
6489                         cache->last_byte_to_unpin = caching_ctl->progress;
6490                 }
6491         }
6492
6493         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6494                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6495         else
6496                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6497
6498         up_write(&fs_info->commit_root_sem);
6499
6500         update_global_block_rsv(fs_info);
6501 }
6502
6503 /*
6504  * Returns the free cluster for the given space info and sets empty_cluster to
6505  * what it should be based on the mount options.
6506  */
6507 static struct btrfs_free_cluster *
6508 fetch_cluster_info(struct btrfs_fs_info *fs_info,
6509                    struct btrfs_space_info *space_info, u64 *empty_cluster)
6510 {
6511         struct btrfs_free_cluster *ret = NULL;
6512
6513         *empty_cluster = 0;
6514         if (btrfs_mixed_space_info(space_info))
6515                 return ret;
6516
6517         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6518                 ret = &fs_info->meta_alloc_cluster;
6519                 if (btrfs_test_opt(fs_info, SSD))
6520                         *empty_cluster = SZ_2M;
6521                 else
6522                         *empty_cluster = SZ_64K;
6523         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
6524                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
6525                 *empty_cluster = SZ_2M;
6526                 ret = &fs_info->data_alloc_cluster;
6527         }
6528
6529         return ret;
6530 }
6531
6532 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
6533                               u64 start, u64 end,
6534                               const bool return_free_space)
6535 {
6536         struct btrfs_block_group_cache *cache = NULL;
6537         struct btrfs_space_info *space_info;
6538         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6539         struct btrfs_free_cluster *cluster = NULL;
6540         u64 len;
6541         u64 total_unpinned = 0;
6542         u64 empty_cluster = 0;
6543         bool readonly;
6544
6545         while (start <= end) {
6546                 readonly = false;
6547                 if (!cache ||
6548                     start >= cache->key.objectid + cache->key.offset) {
6549                         if (cache)
6550                                 btrfs_put_block_group(cache);
6551                         total_unpinned = 0;
6552                         cache = btrfs_lookup_block_group(fs_info, start);
6553                         BUG_ON(!cache); /* Logic error */
6554
6555                         cluster = fetch_cluster_info(fs_info,
6556                                                      cache->space_info,
6557                                                      &empty_cluster);
6558                         empty_cluster <<= 1;
6559                 }
6560
6561                 len = cache->key.objectid + cache->key.offset - start;
6562                 len = min(len, end + 1 - start);
6563
6564                 if (start < cache->last_byte_to_unpin) {
6565                         len = min(len, cache->last_byte_to_unpin - start);
6566                         if (return_free_space)
6567                                 btrfs_add_free_space(cache, start, len);
6568                 }
6569
6570                 start += len;
6571                 total_unpinned += len;
6572                 space_info = cache->space_info;
6573
6574                 /*
6575                  * If this space cluster has been marked as fragmented and we've
6576                  * unpinned enough in this block group to potentially allow a
6577                  * cluster to be created inside of it go ahead and clear the
6578                  * fragmented check.
6579                  */
6580                 if (cluster && cluster->fragmented &&
6581                     total_unpinned > empty_cluster) {
6582                         spin_lock(&cluster->lock);
6583                         cluster->fragmented = 0;
6584                         spin_unlock(&cluster->lock);
6585                 }
6586
6587                 spin_lock(&space_info->lock);
6588                 spin_lock(&cache->lock);
6589                 cache->pinned -= len;
6590                 space_info->bytes_pinned -= len;
6591
6592                 trace_btrfs_space_reservation(fs_info, "pinned",
6593                                               space_info->flags, len, 0);
6594                 space_info->max_extent_size = 0;
6595                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
6596                             -len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
6597                 if (cache->ro) {
6598                         space_info->bytes_readonly += len;
6599                         readonly = true;
6600                 }
6601                 spin_unlock(&cache->lock);
6602                 if (!readonly && return_free_space &&
6603                     global_rsv->space_info == space_info) {
6604                         u64 to_add = len;
6605
6606                         spin_lock(&global_rsv->lock);
6607                         if (!global_rsv->full) {
6608                                 to_add = min(len, global_rsv->size -
6609                                              global_rsv->reserved);
6610                                 global_rsv->reserved += to_add;
6611                                 space_info->bytes_may_use += to_add;
6612                                 if (global_rsv->reserved >= global_rsv->size)
6613                                         global_rsv->full = 1;
6614                                 trace_btrfs_space_reservation(fs_info,
6615                                                               "space_info",
6616                                                               space_info->flags,
6617                                                               to_add, 1);
6618                                 len -= to_add;
6619                         }
6620                         spin_unlock(&global_rsv->lock);
6621                         /* Add to any tickets we may have */
6622                         if (len)
6623                                 space_info_add_new_bytes(fs_info, space_info,
6624                                                          len);
6625                 }
6626                 spin_unlock(&space_info->lock);
6627         }
6628
6629         if (cache)
6630                 btrfs_put_block_group(cache);
6631         return 0;
6632 }
6633
6634 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
6635 {
6636         struct btrfs_fs_info *fs_info = trans->fs_info;
6637         struct btrfs_block_group_cache *block_group, *tmp;
6638         struct list_head *deleted_bgs;
6639         struct extent_io_tree *unpin;
6640         u64 start;
6641         u64 end;
6642         int ret;
6643
6644         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6645                 unpin = &fs_info->freed_extents[1];
6646         else
6647                 unpin = &fs_info->freed_extents[0];
6648
6649         while (!trans->aborted) {
6650                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6651                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6652                                             EXTENT_DIRTY, NULL);
6653                 if (ret) {
6654                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6655                         break;
6656                 }
6657
6658                 if (btrfs_test_opt(fs_info, DISCARD))
6659                         ret = btrfs_discard_extent(fs_info, start,
6660                                                    end + 1 - start, NULL);
6661
6662                 clear_extent_dirty(unpin, start, end);
6663                 unpin_extent_range(fs_info, start, end, true);
6664                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6665                 cond_resched();
6666         }
6667
6668         /*
6669          * Transaction is finished.  We don't need the lock anymore.  We
6670          * do need to clean up the block groups in case of a transaction
6671          * abort.
6672          */
6673         deleted_bgs = &trans->transaction->deleted_bgs;
6674         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6675                 u64 trimmed = 0;
6676
6677                 ret = -EROFS;
6678                 if (!trans->aborted)
6679                         ret = btrfs_discard_extent(fs_info,
6680                                                    block_group->key.objectid,
6681                                                    block_group->key.offset,
6682                                                    &trimmed);
6683
6684                 list_del_init(&block_group->bg_list);
6685                 btrfs_put_block_group_trimming(block_group);
6686                 btrfs_put_block_group(block_group);
6687
6688                 if (ret) {
6689                         const char *errstr = btrfs_decode_error(ret);
6690                         btrfs_warn(fs_info,
6691                            "discard failed while removing blockgroup: errno=%d %s",
6692                                    ret, errstr);
6693                 }
6694         }
6695
6696         return 0;
6697 }
6698
6699 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6700                                struct btrfs_delayed_ref_node *node, u64 parent,
6701                                u64 root_objectid, u64 owner_objectid,
6702                                u64 owner_offset, int refs_to_drop,
6703                                struct btrfs_delayed_extent_op *extent_op)
6704 {
6705         struct btrfs_fs_info *info = trans->fs_info;
6706         struct btrfs_key key;
6707         struct btrfs_path *path;
6708         struct btrfs_root *extent_root = info->extent_root;
6709         struct extent_buffer *leaf;
6710         struct btrfs_extent_item *ei;
6711         struct btrfs_extent_inline_ref *iref;
6712         int ret;
6713         int is_data;
6714         int extent_slot = 0;
6715         int found_extent = 0;
6716         int num_to_del = 1;
6717         u32 item_size;
6718         u64 refs;
6719         u64 bytenr = node->bytenr;
6720         u64 num_bytes = node->num_bytes;
6721         int last_ref = 0;
6722         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
6723
6724         path = btrfs_alloc_path();
6725         if (!path)
6726                 return -ENOMEM;
6727
6728         path->reada = READA_FORWARD;
6729         path->leave_spinning = 1;
6730
6731         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6732         BUG_ON(!is_data && refs_to_drop != 1);
6733
6734         if (is_data)
6735                 skinny_metadata = false;
6736
6737         ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
6738                                     parent, root_objectid, owner_objectid,
6739                                     owner_offset);
6740         if (ret == 0) {
6741                 extent_slot = path->slots[0];
6742                 while (extent_slot >= 0) {
6743                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6744                                               extent_slot);
6745                         if (key.objectid != bytenr)
6746                                 break;
6747                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6748                             key.offset == num_bytes) {
6749                                 found_extent = 1;
6750                                 break;
6751                         }
6752                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6753                             key.offset == owner_objectid) {
6754                                 found_extent = 1;
6755                                 break;
6756                         }
6757                         if (path->slots[0] - extent_slot > 5)
6758                                 break;
6759                         extent_slot--;
6760                 }
6761
6762                 if (!found_extent) {
6763                         BUG_ON(iref);
6764                         ret = remove_extent_backref(trans, path, NULL,
6765                                                     refs_to_drop,
6766                                                     is_data, &last_ref);
6767                         if (ret) {
6768                                 btrfs_abort_transaction(trans, ret);
6769                                 goto out;
6770                         }
6771                         btrfs_release_path(path);
6772                         path->leave_spinning = 1;
6773
6774                         key.objectid = bytenr;
6775                         key.type = BTRFS_EXTENT_ITEM_KEY;
6776                         key.offset = num_bytes;
6777
6778                         if (!is_data && skinny_metadata) {
6779                                 key.type = BTRFS_METADATA_ITEM_KEY;
6780                                 key.offset = owner_objectid;
6781                         }
6782
6783                         ret = btrfs_search_slot(trans, extent_root,
6784                                                 &key, path, -1, 1);
6785                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6786                                 /*
6787                                  * Couldn't find our skinny metadata item,
6788                                  * see if we have ye olde extent item.
6789                                  */
6790                                 path->slots[0]--;
6791                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6792                                                       path->slots[0]);
6793                                 if (key.objectid == bytenr &&
6794                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6795                                     key.offset == num_bytes)
6796                                         ret = 0;
6797                         }
6798
6799                         if (ret > 0 && skinny_metadata) {
6800                                 skinny_metadata = false;
6801                                 key.objectid = bytenr;
6802                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6803                                 key.offset = num_bytes;
6804                                 btrfs_release_path(path);
6805                                 ret = btrfs_search_slot(trans, extent_root,
6806                                                         &key, path, -1, 1);
6807                         }
6808
6809                         if (ret) {
6810                                 btrfs_err(info,
6811                                           "umm, got %d back from search, was looking for %llu",
6812                                           ret, bytenr);
6813                                 if (ret > 0)
6814                                         btrfs_print_leaf(path->nodes[0]);
6815                         }
6816                         if (ret < 0) {
6817                                 btrfs_abort_transaction(trans, ret);
6818                                 goto out;
6819                         }
6820                         extent_slot = path->slots[0];
6821                 }
6822         } else if (WARN_ON(ret == -ENOENT)) {
6823                 btrfs_print_leaf(path->nodes[0]);
6824                 btrfs_err(info,
6825                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6826                         bytenr, parent, root_objectid, owner_objectid,
6827                         owner_offset);
6828                 btrfs_abort_transaction(trans, ret);
6829                 goto out;
6830         } else {
6831                 btrfs_abort_transaction(trans, ret);
6832                 goto out;
6833         }
6834
6835         leaf = path->nodes[0];
6836         item_size = btrfs_item_size_nr(leaf, extent_slot);
6837         if (unlikely(item_size < sizeof(*ei))) {
6838                 ret = -EINVAL;
6839                 btrfs_print_v0_err(info);
6840                 btrfs_abort_transaction(trans, ret);
6841                 goto out;
6842         }
6843         ei = btrfs_item_ptr(leaf, extent_slot,
6844                             struct btrfs_extent_item);
6845         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6846             key.type == BTRFS_EXTENT_ITEM_KEY) {
6847                 struct btrfs_tree_block_info *bi;
6848                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6849                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6850                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6851         }
6852
6853         refs = btrfs_extent_refs(leaf, ei);
6854         if (refs < refs_to_drop) {
6855                 btrfs_err(info,
6856                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
6857                           refs_to_drop, refs, bytenr);
6858                 ret = -EINVAL;
6859                 btrfs_abort_transaction(trans, ret);
6860                 goto out;
6861         }
6862         refs -= refs_to_drop;
6863
6864         if (refs > 0) {
6865                 if (extent_op)
6866                         __run_delayed_extent_op(extent_op, leaf, ei);
6867                 /*
6868                  * In the case of inline back ref, reference count will
6869                  * be updated by remove_extent_backref
6870                  */
6871                 if (iref) {
6872                         BUG_ON(!found_extent);
6873                 } else {
6874                         btrfs_set_extent_refs(leaf, ei, refs);
6875                         btrfs_mark_buffer_dirty(leaf);
6876                 }
6877                 if (found_extent) {
6878                         ret = remove_extent_backref(trans, path, iref,
6879                                                     refs_to_drop, is_data,
6880                                                     &last_ref);
6881                         if (ret) {
6882                                 btrfs_abort_transaction(trans, ret);
6883                                 goto out;
6884                         }
6885                 }
6886         } else {
6887                 if (found_extent) {
6888                         BUG_ON(is_data && refs_to_drop !=
6889                                extent_data_ref_count(path, iref));
6890                         if (iref) {
6891                                 BUG_ON(path->slots[0] != extent_slot);
6892                         } else {
6893                                 BUG_ON(path->slots[0] != extent_slot + 1);
6894                                 path->slots[0] = extent_slot;
6895                                 num_to_del = 2;
6896                         }
6897                 }
6898
6899                 last_ref = 1;
6900                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6901                                       num_to_del);
6902                 if (ret) {
6903                         btrfs_abort_transaction(trans, ret);
6904                         goto out;
6905                 }
6906                 btrfs_release_path(path);
6907
6908                 if (is_data) {
6909                         ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
6910                         if (ret) {
6911                                 btrfs_abort_transaction(trans, ret);
6912                                 goto out;
6913                         }
6914                 }
6915
6916                 ret = add_to_free_space_tree(trans, bytenr, num_bytes);
6917                 if (ret) {
6918                         btrfs_abort_transaction(trans, ret);
6919                         goto out;
6920                 }
6921
6922                 ret = update_block_group(trans, info, bytenr, num_bytes, 0);
6923                 if (ret) {
6924                         btrfs_abort_transaction(trans, ret);
6925                         goto out;
6926                 }
6927         }
6928         btrfs_release_path(path);
6929
6930 out:
6931         btrfs_free_path(path);
6932         return ret;
6933 }
6934
6935 /*
6936  * when we free an block, it is possible (and likely) that we free the last
6937  * delayed ref for that extent as well.  This searches the delayed ref tree for
6938  * a given extent, and if there are no other delayed refs to be processed, it
6939  * removes it from the tree.
6940  */
6941 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6942                                       u64 bytenr)
6943 {
6944         struct btrfs_delayed_ref_head *head;
6945         struct btrfs_delayed_ref_root *delayed_refs;
6946         int ret = 0;
6947
6948         delayed_refs = &trans->transaction->delayed_refs;
6949         spin_lock(&delayed_refs->lock);
6950         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
6951         if (!head)
6952                 goto out_delayed_unlock;
6953
6954         spin_lock(&head->lock);
6955         if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
6956                 goto out;
6957
6958         if (head->extent_op) {
6959                 if (!head->must_insert_reserved)
6960                         goto out;
6961                 btrfs_free_delayed_extent_op(head->extent_op);
6962                 head->extent_op = NULL;
6963         }
6964
6965         /*
6966          * waiting for the lock here would deadlock.  If someone else has it
6967          * locked they are already in the process of dropping it anyway
6968          */
6969         if (!mutex_trylock(&head->mutex))
6970                 goto out;
6971
6972         /*
6973          * at this point we have a head with no other entries.  Go
6974          * ahead and process it.
6975          */
6976         rb_erase_cached(&head->href_node, &delayed_refs->href_root);
6977         RB_CLEAR_NODE(&head->href_node);
6978         atomic_dec(&delayed_refs->num_entries);
6979
6980         /*
6981          * we don't take a ref on the node because we're removing it from the
6982          * tree, so we just steal the ref the tree was holding.
6983          */
6984         delayed_refs->num_heads--;
6985         if (head->processing == 0)
6986                 delayed_refs->num_heads_ready--;
6987         head->processing = 0;
6988         spin_unlock(&head->lock);
6989         spin_unlock(&delayed_refs->lock);
6990
6991         BUG_ON(head->extent_op);
6992         if (head->must_insert_reserved)
6993                 ret = 1;
6994
6995         mutex_unlock(&head->mutex);
6996         btrfs_put_delayed_ref_head(head);
6997         return ret;
6998 out:
6999         spin_unlock(&head->lock);
7000
7001 out_delayed_unlock:
7002         spin_unlock(&delayed_refs->lock);
7003         return 0;
7004 }
7005
7006 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7007                            struct btrfs_root *root,
7008                            struct extent_buffer *buf,
7009                            u64 parent, int last_ref)
7010 {
7011         struct btrfs_fs_info *fs_info = root->fs_info;
7012         int pin = 1;
7013         int ret;
7014
7015         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7016                 int old_ref_mod, new_ref_mod;
7017
7018                 btrfs_ref_tree_mod(root, buf->start, buf->len, parent,
7019                                    root->root_key.objectid,
7020                                    btrfs_header_level(buf), 0,
7021                                    BTRFS_DROP_DELAYED_REF);
7022                 ret = btrfs_add_delayed_tree_ref(trans, buf->start,
7023                                                  buf->len, parent,
7024                                                  root->root_key.objectid,
7025                                                  btrfs_header_level(buf),
7026                                                  BTRFS_DROP_DELAYED_REF, NULL,
7027                                                  &old_ref_mod, &new_ref_mod);
7028                 BUG_ON(ret); /* -ENOMEM */
7029                 pin = old_ref_mod >= 0 && new_ref_mod < 0;
7030         }
7031
7032         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
7033                 struct btrfs_block_group_cache *cache;
7034
7035                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7036                         ret = check_ref_cleanup(trans, buf->start);
7037                         if (!ret)
7038                                 goto out;
7039                 }
7040
7041                 pin = 0;
7042                 cache = btrfs_lookup_block_group(fs_info, buf->start);
7043
7044                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7045                         pin_down_extent(fs_info, cache, buf->start,
7046                                         buf->len, 1);
7047                         btrfs_put_block_group(cache);
7048                         goto out;
7049                 }
7050
7051                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7052
7053                 btrfs_add_free_space(cache, buf->start, buf->len);
7054                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7055                 btrfs_put_block_group(cache);
7056                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
7057         }
7058 out:
7059         if (pin)
7060                 add_pinned_bytes(fs_info, buf->len, true,
7061                                  root->root_key.objectid);
7062
7063         if (last_ref) {
7064                 /*
7065                  * Deleting the buffer, clear the corrupt flag since it doesn't
7066                  * matter anymore.
7067                  */
7068                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7069         }
7070 }
7071
7072 /* Can return -ENOMEM */
7073 int btrfs_free_extent(struct btrfs_trans_handle *trans,
7074                       struct btrfs_root *root,
7075                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7076                       u64 owner, u64 offset)
7077 {
7078         struct btrfs_fs_info *fs_info = root->fs_info;
7079         int old_ref_mod, new_ref_mod;
7080         int ret;
7081
7082         if (btrfs_is_testing(fs_info))
7083                 return 0;
7084
7085         if (root_objectid != BTRFS_TREE_LOG_OBJECTID)
7086                 btrfs_ref_tree_mod(root, bytenr, num_bytes, parent,
7087                                    root_objectid, owner, offset,
7088                                    BTRFS_DROP_DELAYED_REF);
7089
7090         /*
7091          * tree log blocks never actually go into the extent allocation
7092          * tree, just update pinning info and exit early.
7093          */
7094         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7095                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7096                 /* unlocks the pinned mutex */
7097                 btrfs_pin_extent(fs_info, bytenr, num_bytes, 1);
7098                 old_ref_mod = new_ref_mod = 0;
7099                 ret = 0;
7100         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7101                 ret = btrfs_add_delayed_tree_ref(trans, bytenr,
7102                                                  num_bytes, parent,
7103                                                  root_objectid, (int)owner,
7104                                                  BTRFS_DROP_DELAYED_REF, NULL,
7105                                                  &old_ref_mod, &new_ref_mod);
7106         } else {
7107                 ret = btrfs_add_delayed_data_ref(trans, bytenr,
7108                                                  num_bytes, parent,
7109                                                  root_objectid, owner, offset,
7110                                                  0, BTRFS_DROP_DELAYED_REF,
7111                                                  &old_ref_mod, &new_ref_mod);
7112         }
7113
7114         if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0) {
7115                 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
7116
7117                 add_pinned_bytes(fs_info, num_bytes, metadata, root_objectid);
7118         }
7119
7120         return ret;
7121 }
7122
7123 /*
7124  * when we wait for progress in the block group caching, its because
7125  * our allocation attempt failed at least once.  So, we must sleep
7126  * and let some progress happen before we try again.
7127  *
7128  * This function will sleep at least once waiting for new free space to
7129  * show up, and then it will check the block group free space numbers
7130  * for our min num_bytes.  Another option is to have it go ahead
7131  * and look in the rbtree for a free extent of a given size, but this
7132  * is a good start.
7133  *
7134  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7135  * any of the information in this block group.
7136  */
7137 static noinline void
7138 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7139                                 u64 num_bytes)
7140 {
7141         struct btrfs_caching_control *caching_ctl;
7142
7143         caching_ctl = get_caching_control(cache);
7144         if (!caching_ctl)
7145                 return;
7146
7147         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7148                    (cache->free_space_ctl->free_space >= num_bytes));
7149
7150         put_caching_control(caching_ctl);
7151 }
7152
7153 static noinline int
7154 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7155 {
7156         struct btrfs_caching_control *caching_ctl;
7157         int ret = 0;
7158
7159         caching_ctl = get_caching_control(cache);
7160         if (!caching_ctl)
7161                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7162
7163         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7164         if (cache->cached == BTRFS_CACHE_ERROR)
7165                 ret = -EIO;
7166         put_caching_control(caching_ctl);
7167         return ret;
7168 }
7169
7170 enum btrfs_loop_type {
7171         LOOP_CACHING_NOWAIT = 0,
7172         LOOP_CACHING_WAIT = 1,
7173         LOOP_ALLOC_CHUNK = 2,
7174         LOOP_NO_EMPTY_SIZE = 3,
7175 };
7176
7177 static inline void
7178 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7179                        int delalloc)
7180 {
7181         if (delalloc)
7182                 down_read(&cache->data_rwsem);
7183 }
7184
7185 static inline void
7186 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7187                        int delalloc)
7188 {
7189         btrfs_get_block_group(cache);
7190         if (delalloc)
7191                 down_read(&cache->data_rwsem);
7192 }
7193
7194 static struct btrfs_block_group_cache *
7195 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7196                    struct btrfs_free_cluster *cluster,
7197                    int delalloc)
7198 {
7199         struct btrfs_block_group_cache *used_bg = NULL;
7200
7201         spin_lock(&cluster->refill_lock);
7202         while (1) {
7203                 used_bg = cluster->block_group;
7204                 if (!used_bg)
7205                         return NULL;
7206
7207                 if (used_bg == block_group)
7208                         return used_bg;
7209
7210                 btrfs_get_block_group(used_bg);
7211
7212                 if (!delalloc)
7213                         return used_bg;
7214
7215                 if (down_read_trylock(&used_bg->data_rwsem))
7216                         return used_bg;
7217
7218                 spin_unlock(&cluster->refill_lock);
7219
7220                 /* We should only have one-level nested. */
7221                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
7222
7223                 spin_lock(&cluster->refill_lock);
7224                 if (used_bg == cluster->block_group)
7225                         return used_bg;
7226
7227                 up_read(&used_bg->data_rwsem);
7228                 btrfs_put_block_group(used_bg);
7229         }
7230 }
7231
7232 static inline void
7233 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7234                          int delalloc)
7235 {
7236         if (delalloc)
7237                 up_read(&cache->data_rwsem);
7238         btrfs_put_block_group(cache);
7239 }
7240
7241 /*
7242  * walks the btree of allocated extents and find a hole of a given size.
7243  * The key ins is changed to record the hole:
7244  * ins->objectid == start position
7245  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7246  * ins->offset == the size of the hole.
7247  * Any available blocks before search_start are skipped.
7248  *
7249  * If there is no suitable free space, we will record the max size of
7250  * the free space extent currently.
7251  */
7252 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
7253                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7254                                 u64 hint_byte, struct btrfs_key *ins,
7255                                 u64 flags, int delalloc)
7256 {
7257         int ret = 0;
7258         struct btrfs_root *root = fs_info->extent_root;
7259         struct btrfs_free_cluster *last_ptr = NULL;
7260         struct btrfs_block_group_cache *block_group = NULL;
7261         u64 search_start = 0;
7262         u64 max_extent_size = 0;
7263         u64 max_free_space = 0;
7264         u64 empty_cluster = 0;
7265         struct btrfs_space_info *space_info;
7266         int loop = 0;
7267         int index = btrfs_bg_flags_to_raid_index(flags);
7268         bool failed_cluster_refill = false;
7269         bool failed_alloc = false;
7270         bool use_cluster = true;
7271         bool have_caching_bg = false;
7272         bool orig_have_caching_bg = false;
7273         bool full_search = false;
7274
7275         WARN_ON(num_bytes < fs_info->sectorsize);
7276         ins->type = BTRFS_EXTENT_ITEM_KEY;
7277         ins->objectid = 0;
7278         ins->offset = 0;
7279
7280         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
7281
7282         space_info = __find_space_info(fs_info, flags);
7283         if (!space_info) {
7284                 btrfs_err(fs_info, "No space info for %llu", flags);
7285                 return -ENOSPC;
7286         }
7287
7288         /*
7289          * If our free space is heavily fragmented we may not be able to make
7290          * big contiguous allocations, so instead of doing the expensive search
7291          * for free space, simply return ENOSPC with our max_extent_size so we
7292          * can go ahead and search for a more manageable chunk.
7293          *
7294          * If our max_extent_size is large enough for our allocation simply
7295          * disable clustering since we will likely not be able to find enough
7296          * space to create a cluster and induce latency trying.
7297          */
7298         if (unlikely(space_info->max_extent_size)) {
7299                 spin_lock(&space_info->lock);
7300                 if (space_info->max_extent_size &&
7301                     num_bytes > space_info->max_extent_size) {
7302                         ins->offset = space_info->max_extent_size;
7303                         spin_unlock(&space_info->lock);
7304                         return -ENOSPC;
7305                 } else if (space_info->max_extent_size) {
7306                         use_cluster = false;
7307                 }
7308                 spin_unlock(&space_info->lock);
7309         }
7310
7311         last_ptr = fetch_cluster_info(fs_info, space_info, &empty_cluster);
7312         if (last_ptr) {
7313                 spin_lock(&last_ptr->lock);
7314                 if (last_ptr->block_group)
7315                         hint_byte = last_ptr->window_start;
7316                 if (last_ptr->fragmented) {
7317                         /*
7318                          * We still set window_start so we can keep track of the
7319                          * last place we found an allocation to try and save
7320                          * some time.
7321                          */
7322                         hint_byte = last_ptr->window_start;
7323                         use_cluster = false;
7324                 }
7325                 spin_unlock(&last_ptr->lock);
7326         }
7327
7328         search_start = max(search_start, first_logical_byte(fs_info, 0));
7329         search_start = max(search_start, hint_byte);
7330         if (search_start == hint_byte) {
7331                 block_group = btrfs_lookup_block_group(fs_info, search_start);
7332                 /*
7333                  * we don't want to use the block group if it doesn't match our
7334                  * allocation bits, or if its not cached.
7335                  *
7336                  * However if we are re-searching with an ideal block group
7337                  * picked out then we don't care that the block group is cached.
7338                  */
7339                 if (block_group && block_group_bits(block_group, flags) &&
7340                     block_group->cached != BTRFS_CACHE_NO) {
7341                         down_read(&space_info->groups_sem);
7342                         if (list_empty(&block_group->list) ||
7343                             block_group->ro) {
7344                                 /*
7345                                  * someone is removing this block group,
7346                                  * we can't jump into the have_block_group
7347                                  * target because our list pointers are not
7348                                  * valid
7349                                  */
7350                                 btrfs_put_block_group(block_group);
7351                                 up_read(&space_info->groups_sem);
7352                         } else {
7353                                 index = btrfs_bg_flags_to_raid_index(
7354                                                 block_group->flags);
7355                                 btrfs_lock_block_group(block_group, delalloc);
7356                                 goto have_block_group;
7357                         }
7358                 } else if (block_group) {
7359                         btrfs_put_block_group(block_group);
7360                 }
7361         }
7362 search:
7363         have_caching_bg = false;
7364         if (index == 0 || index == btrfs_bg_flags_to_raid_index(flags))
7365                 full_search = true;
7366         down_read(&space_info->groups_sem);
7367         list_for_each_entry(block_group, &space_info->block_groups[index],
7368                             list) {
7369                 u64 offset;
7370                 int cached;
7371
7372                 /* If the block group is read-only, we can skip it entirely. */
7373                 if (unlikely(block_group->ro))
7374                         continue;
7375
7376                 btrfs_grab_block_group(block_group, delalloc);
7377                 search_start = block_group->key.objectid;
7378
7379                 /*
7380                  * this can happen if we end up cycling through all the
7381                  * raid types, but we want to make sure we only allocate
7382                  * for the proper type.
7383                  */
7384                 if (!block_group_bits(block_group, flags)) {
7385                         u64 extra = BTRFS_BLOCK_GROUP_DUP |
7386                                 BTRFS_BLOCK_GROUP_RAID1 |
7387                                 BTRFS_BLOCK_GROUP_RAID5 |
7388                                 BTRFS_BLOCK_GROUP_RAID6 |
7389                                 BTRFS_BLOCK_GROUP_RAID10;
7390
7391                         /*
7392                          * if they asked for extra copies and this block group
7393                          * doesn't provide them, bail.  This does allow us to
7394                          * fill raid0 from raid1.
7395                          */
7396                         if ((flags & extra) && !(block_group->flags & extra))
7397                                 goto loop;
7398                 }
7399
7400 have_block_group:
7401                 cached = block_group_cache_done(block_group);
7402                 if (unlikely(!cached)) {
7403                         have_caching_bg = true;
7404                         ret = cache_block_group(block_group, 0);
7405                         BUG_ON(ret < 0);
7406                         ret = 0;
7407                 }
7408
7409                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7410                         goto loop;
7411
7412                 /*
7413                  * Ok we want to try and use the cluster allocator, so
7414                  * lets look there
7415                  */
7416                 if (last_ptr && use_cluster) {
7417                         struct btrfs_block_group_cache *used_block_group;
7418                         unsigned long aligned_cluster;
7419                         /*
7420                          * the refill lock keeps out other
7421                          * people trying to start a new cluster
7422                          */
7423                         used_block_group = btrfs_lock_cluster(block_group,
7424                                                               last_ptr,
7425                                                               delalloc);
7426                         if (!used_block_group)
7427                                 goto refill_cluster;
7428
7429                         if (used_block_group != block_group &&
7430                             (used_block_group->ro ||
7431                              !block_group_bits(used_block_group, flags)))
7432                                 goto release_cluster;
7433
7434                         offset = btrfs_alloc_from_cluster(used_block_group,
7435                                                 last_ptr,
7436                                                 num_bytes,
7437                                                 used_block_group->key.objectid,
7438                                                 &max_extent_size);
7439                         if (offset) {
7440                                 /* we have a block, we're done */
7441                                 spin_unlock(&last_ptr->refill_lock);
7442                                 trace_btrfs_reserve_extent_cluster(
7443                                                 used_block_group,
7444                                                 search_start, num_bytes);
7445                                 if (used_block_group != block_group) {
7446                                         btrfs_release_block_group(block_group,
7447                                                                   delalloc);
7448                                         block_group = used_block_group;
7449                                 }
7450                                 goto checks;
7451                         }
7452
7453                         WARN_ON(last_ptr->block_group != used_block_group);
7454 release_cluster:
7455                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7456                          * set up a new clusters, so lets just skip it
7457                          * and let the allocator find whatever block
7458                          * it can find.  If we reach this point, we
7459                          * will have tried the cluster allocator
7460                          * plenty of times and not have found
7461                          * anything, so we are likely way too
7462                          * fragmented for the clustering stuff to find
7463                          * anything.
7464                          *
7465                          * However, if the cluster is taken from the
7466                          * current block group, release the cluster
7467                          * first, so that we stand a better chance of
7468                          * succeeding in the unclustered
7469                          * allocation.  */
7470                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7471                             used_block_group != block_group) {
7472                                 spin_unlock(&last_ptr->refill_lock);
7473                                 btrfs_release_block_group(used_block_group,
7474                                                           delalloc);
7475                                 goto unclustered_alloc;
7476                         }
7477
7478                         /*
7479                          * this cluster didn't work out, free it and
7480                          * start over
7481                          */
7482                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7483
7484                         if (used_block_group != block_group)
7485                                 btrfs_release_block_group(used_block_group,
7486                                                           delalloc);
7487 refill_cluster:
7488                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7489                                 spin_unlock(&last_ptr->refill_lock);
7490                                 goto unclustered_alloc;
7491                         }
7492
7493                         aligned_cluster = max_t(unsigned long,
7494                                                 empty_cluster + empty_size,
7495                                               block_group->full_stripe_len);
7496
7497                         /* allocate a cluster in this block group */
7498                         ret = btrfs_find_space_cluster(fs_info, block_group,
7499                                                        last_ptr, search_start,
7500                                                        num_bytes,
7501                                                        aligned_cluster);
7502                         if (ret == 0) {
7503                                 /*
7504                                  * now pull our allocation out of this
7505                                  * cluster
7506                                  */
7507                                 offset = btrfs_alloc_from_cluster(block_group,
7508                                                         last_ptr,
7509                                                         num_bytes,
7510                                                         search_start,
7511                                                         &max_extent_size);
7512                                 if (offset) {
7513                                         /* we found one, proceed */
7514                                         spin_unlock(&last_ptr->refill_lock);
7515                                         trace_btrfs_reserve_extent_cluster(
7516                                                 block_group, search_start,
7517                                                 num_bytes);
7518                                         goto checks;
7519                                 }
7520                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7521                                    && !failed_cluster_refill) {
7522                                 spin_unlock(&last_ptr->refill_lock);
7523
7524                                 failed_cluster_refill = true;
7525                                 wait_block_group_cache_progress(block_group,
7526                                        num_bytes + empty_cluster + empty_size);
7527                                 goto have_block_group;
7528                         }
7529
7530                         /*
7531                          * at this point we either didn't find a cluster
7532                          * or we weren't able to allocate a block from our
7533                          * cluster.  Free the cluster we've been trying
7534                          * to use, and go to the next block group
7535                          */
7536                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7537                         spin_unlock(&last_ptr->refill_lock);
7538                         goto loop;
7539                 }
7540
7541 unclustered_alloc:
7542                 /*
7543                  * We are doing an unclustered alloc, set the fragmented flag so
7544                  * we don't bother trying to setup a cluster again until we get
7545                  * more space.
7546                  */
7547                 if (unlikely(last_ptr)) {
7548                         spin_lock(&last_ptr->lock);
7549                         last_ptr->fragmented = 1;
7550                         spin_unlock(&last_ptr->lock);
7551                 }
7552                 if (cached) {
7553                         struct btrfs_free_space_ctl *ctl =
7554                                 block_group->free_space_ctl;
7555
7556                         spin_lock(&ctl->tree_lock);
7557                         if (ctl->free_space <
7558                             num_bytes + empty_cluster + empty_size) {
7559                                 max_free_space = max(max_free_space,
7560                                                      ctl->free_space);
7561                                 spin_unlock(&ctl->tree_lock);
7562                                 goto loop;
7563                         }
7564                         spin_unlock(&ctl->tree_lock);
7565                 }
7566
7567                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7568                                                     num_bytes, empty_size,
7569                                                     &max_extent_size);
7570                 /*
7571                  * If we didn't find a chunk, and we haven't failed on this
7572                  * block group before, and this block group is in the middle of
7573                  * caching and we are ok with waiting, then go ahead and wait
7574                  * for progress to be made, and set failed_alloc to true.
7575                  *
7576                  * If failed_alloc is true then we've already waited on this
7577                  * block group once and should move on to the next block group.
7578                  */
7579                 if (!offset && !failed_alloc && !cached &&
7580                     loop > LOOP_CACHING_NOWAIT) {
7581                         wait_block_group_cache_progress(block_group,
7582                                                 num_bytes + empty_size);
7583                         failed_alloc = true;
7584                         goto have_block_group;
7585                 } else if (!offset) {
7586                         goto loop;
7587                 }
7588 checks:
7589                 search_start = round_up(offset, fs_info->stripesize);
7590
7591                 /* move on to the next group */
7592                 if (search_start + num_bytes >
7593                     block_group->key.objectid + block_group->key.offset) {
7594                         btrfs_add_free_space(block_group, offset, num_bytes);
7595                         goto loop;
7596                 }
7597
7598                 if (offset < search_start)
7599                         btrfs_add_free_space(block_group, offset,
7600                                              search_start - offset);
7601
7602                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7603                                 num_bytes, delalloc);
7604                 if (ret == -EAGAIN) {
7605                         btrfs_add_free_space(block_group, offset, num_bytes);
7606                         goto loop;
7607                 }
7608                 btrfs_inc_block_group_reservations(block_group);
7609
7610                 /* we are all good, lets return */
7611                 ins->objectid = search_start;
7612                 ins->offset = num_bytes;
7613
7614                 trace_btrfs_reserve_extent(block_group, search_start, num_bytes);
7615                 btrfs_release_block_group(block_group, delalloc);
7616                 break;
7617 loop:
7618                 failed_cluster_refill = false;
7619                 failed_alloc = false;
7620                 BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
7621                        index);
7622                 btrfs_release_block_group(block_group, delalloc);
7623                 cond_resched();
7624         }
7625         up_read(&space_info->groups_sem);
7626
7627         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7628                 && !orig_have_caching_bg)
7629                 orig_have_caching_bg = true;
7630
7631         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7632                 goto search;
7633
7634         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7635                 goto search;
7636
7637         /*
7638          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7639          *                      caching kthreads as we move along
7640          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7641          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7642          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7643          *                      again
7644          */
7645         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7646                 index = 0;
7647                 if (loop == LOOP_CACHING_NOWAIT) {
7648                         /*
7649                          * We want to skip the LOOP_CACHING_WAIT step if we
7650                          * don't have any uncached bgs and we've already done a
7651                          * full search through.
7652                          */
7653                         if (orig_have_caching_bg || !full_search)
7654                                 loop = LOOP_CACHING_WAIT;
7655                         else
7656                                 loop = LOOP_ALLOC_CHUNK;
7657                 } else {
7658                         loop++;
7659                 }
7660
7661                 if (loop == LOOP_ALLOC_CHUNK) {
7662                         struct btrfs_trans_handle *trans;
7663                         int exist = 0;
7664
7665                         trans = current->journal_info;
7666                         if (trans)
7667                                 exist = 1;
7668                         else
7669                                 trans = btrfs_join_transaction(root);
7670
7671                         if (IS_ERR(trans)) {
7672                                 ret = PTR_ERR(trans);
7673                                 goto out;
7674                         }
7675
7676                         ret = do_chunk_alloc(trans, flags, CHUNK_ALLOC_FORCE);
7677
7678                         /*
7679                          * If we can't allocate a new chunk we've already looped
7680                          * through at least once, move on to the NO_EMPTY_SIZE
7681                          * case.
7682                          */
7683                         if (ret == -ENOSPC)
7684                                 loop = LOOP_NO_EMPTY_SIZE;
7685
7686                         /*
7687                          * Do not bail out on ENOSPC since we
7688                          * can do more things.
7689                          */
7690                         if (ret < 0 && ret != -ENOSPC)
7691                                 btrfs_abort_transaction(trans, ret);
7692                         else
7693                                 ret = 0;
7694                         if (!exist)
7695                                 btrfs_end_transaction(trans);
7696                         if (ret)
7697                                 goto out;
7698                 }
7699
7700                 if (loop == LOOP_NO_EMPTY_SIZE) {
7701                         /*
7702                          * Don't loop again if we already have no empty_size and
7703                          * no empty_cluster.
7704                          */
7705                         if (empty_size == 0 &&
7706                             empty_cluster == 0) {
7707                                 ret = -ENOSPC;
7708                                 goto out;
7709                         }
7710                         empty_size = 0;
7711                         empty_cluster = 0;
7712                 }
7713
7714                 goto search;
7715         } else if (!ins->objectid) {
7716                 ret = -ENOSPC;
7717         } else if (ins->objectid) {
7718                 if (!use_cluster && last_ptr) {
7719                         spin_lock(&last_ptr->lock);
7720                         last_ptr->window_start = ins->objectid;
7721                         spin_unlock(&last_ptr->lock);
7722                 }
7723                 ret = 0;
7724         }
7725 out:
7726         if (ret == -ENOSPC) {
7727                 if (!max_extent_size)
7728                         max_extent_size = max_free_space;
7729                 spin_lock(&space_info->lock);
7730                 space_info->max_extent_size = max_extent_size;
7731                 spin_unlock(&space_info->lock);
7732                 ins->offset = max_extent_size;
7733         }
7734         return ret;
7735 }
7736
7737 static void dump_space_info(struct btrfs_fs_info *fs_info,
7738                             struct btrfs_space_info *info, u64 bytes,
7739                             int dump_block_groups)
7740 {
7741         struct btrfs_block_group_cache *cache;
7742         int index = 0;
7743
7744         spin_lock(&info->lock);
7745         btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
7746                    info->flags,
7747                    info->total_bytes - btrfs_space_info_used(info, true),
7748                    info->full ? "" : "not ");
7749         btrfs_info(fs_info,
7750                 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
7751                 info->total_bytes, info->bytes_used, info->bytes_pinned,
7752                 info->bytes_reserved, info->bytes_may_use,
7753                 info->bytes_readonly);
7754         spin_unlock(&info->lock);
7755
7756         if (!dump_block_groups)
7757                 return;
7758
7759         down_read(&info->groups_sem);
7760 again:
7761         list_for_each_entry(cache, &info->block_groups[index], list) {
7762                 spin_lock(&cache->lock);
7763                 btrfs_info(fs_info,
7764                         "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
7765                         cache->key.objectid, cache->key.offset,
7766                         btrfs_block_group_used(&cache->item), cache->pinned,
7767                         cache->reserved, cache->ro ? "[readonly]" : "");
7768                 btrfs_dump_free_space(cache, bytes);
7769                 spin_unlock(&cache->lock);
7770         }
7771         if (++index < BTRFS_NR_RAID_TYPES)
7772                 goto again;
7773         up_read(&info->groups_sem);
7774 }
7775
7776 /*
7777  * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
7778  *                        hole that is at least as big as @num_bytes.
7779  *
7780  * @root           -    The root that will contain this extent
7781  *
7782  * @ram_bytes      -    The amount of space in ram that @num_bytes take. This
7783  *                      is used for accounting purposes. This value differs
7784  *                      from @num_bytes only in the case of compressed extents.
7785  *
7786  * @num_bytes      -    Number of bytes to allocate on-disk.
7787  *
7788  * @min_alloc_size -    Indicates the minimum amount of space that the
7789  *                      allocator should try to satisfy. In some cases
7790  *                      @num_bytes may be larger than what is required and if
7791  *                      the filesystem is fragmented then allocation fails.
7792  *                      However, the presence of @min_alloc_size gives a
7793  *                      chance to try and satisfy the smaller allocation.
7794  *
7795  * @empty_size     -    A hint that you plan on doing more COW. This is the
7796  *                      size in bytes the allocator should try to find free
7797  *                      next to the block it returns.  This is just a hint and
7798  *                      may be ignored by the allocator.
7799  *
7800  * @hint_byte      -    Hint to the allocator to start searching above the byte
7801  *                      address passed. It might be ignored.
7802  *
7803  * @ins            -    This key is modified to record the found hole. It will
7804  *                      have the following values:
7805  *                      ins->objectid == start position
7806  *                      ins->flags = BTRFS_EXTENT_ITEM_KEY
7807  *                      ins->offset == the size of the hole.
7808  *
7809  * @is_data        -    Boolean flag indicating whether an extent is
7810  *                      allocated for data (true) or metadata (false)
7811  *
7812  * @delalloc       -    Boolean flag indicating whether this allocation is for
7813  *                      delalloc or not. If 'true' data_rwsem of block groups
7814  *                      is going to be acquired.
7815  *
7816  *
7817  * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
7818  * case -ENOSPC is returned then @ins->offset will contain the size of the
7819  * largest available hole the allocator managed to find.
7820  */
7821 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7822                          u64 num_bytes, u64 min_alloc_size,
7823                          u64 empty_size, u64 hint_byte,
7824                          struct btrfs_key *ins, int is_data, int delalloc)
7825 {
7826         struct btrfs_fs_info *fs_info = root->fs_info;
7827         bool final_tried = num_bytes == min_alloc_size;
7828         u64 flags;
7829         int ret;
7830
7831         flags = get_alloc_profile_by_root(root, is_data);
7832 again:
7833         WARN_ON(num_bytes < fs_info->sectorsize);
7834         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
7835                                hint_byte, ins, flags, delalloc);
7836         if (!ret && !is_data) {
7837                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
7838         } else if (ret == -ENOSPC) {
7839                 if (!final_tried && ins->offset) {
7840                         num_bytes = min(num_bytes >> 1, ins->offset);
7841                         num_bytes = round_down(num_bytes,
7842                                                fs_info->sectorsize);
7843                         num_bytes = max(num_bytes, min_alloc_size);
7844                         ram_bytes = num_bytes;
7845                         if (num_bytes == min_alloc_size)
7846                                 final_tried = true;
7847                         goto again;
7848                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
7849                         struct btrfs_space_info *sinfo;
7850
7851                         sinfo = __find_space_info(fs_info, flags);
7852                         btrfs_err(fs_info,
7853                                   "allocation failed flags %llu, wanted %llu",
7854                                   flags, num_bytes);
7855                         if (sinfo)
7856                                 dump_space_info(fs_info, sinfo, num_bytes, 1);
7857                 }
7858         }
7859
7860         return ret;
7861 }
7862
7863 static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
7864                                         u64 start, u64 len,
7865                                         int pin, int delalloc)
7866 {
7867         struct btrfs_block_group_cache *cache;
7868         int ret = 0;
7869
7870         cache = btrfs_lookup_block_group(fs_info, start);
7871         if (!cache) {
7872                 btrfs_err(fs_info, "Unable to find block group for %llu",
7873                           start);
7874                 return -ENOSPC;
7875         }
7876
7877         if (pin)
7878                 pin_down_extent(fs_info, cache, start, len, 1);
7879         else {
7880                 if (btrfs_test_opt(fs_info, DISCARD))
7881                         ret = btrfs_discard_extent(fs_info, start, len, NULL);
7882                 btrfs_add_free_space(cache, start, len);
7883                 btrfs_free_reserved_bytes(cache, len, delalloc);
7884                 trace_btrfs_reserved_extent_free(fs_info, start, len);
7885         }
7886
7887         btrfs_put_block_group(cache);
7888         return ret;
7889 }
7890
7891 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
7892                                u64 start, u64 len, int delalloc)
7893 {
7894         return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
7895 }
7896
7897 int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
7898                                        u64 start, u64 len)
7899 {
7900         return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
7901 }
7902
7903 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7904                                       u64 parent, u64 root_objectid,
7905                                       u64 flags, u64 owner, u64 offset,
7906                                       struct btrfs_key *ins, int ref_mod)
7907 {
7908         struct btrfs_fs_info *fs_info = trans->fs_info;
7909         int ret;
7910         struct btrfs_extent_item *extent_item;
7911         struct btrfs_extent_inline_ref *iref;
7912         struct btrfs_path *path;
7913         struct extent_buffer *leaf;
7914         int type;
7915         u32 size;
7916
7917         if (parent > 0)
7918                 type = BTRFS_SHARED_DATA_REF_KEY;
7919         else
7920                 type = BTRFS_EXTENT_DATA_REF_KEY;
7921
7922         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7923
7924         path = btrfs_alloc_path();
7925         if (!path)
7926                 return -ENOMEM;
7927
7928         path->leave_spinning = 1;
7929         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7930                                       ins, size);
7931         if (ret) {
7932                 btrfs_free_path(path);
7933                 return ret;
7934         }
7935
7936         leaf = path->nodes[0];
7937         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7938                                      struct btrfs_extent_item);
7939         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7940         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7941         btrfs_set_extent_flags(leaf, extent_item,
7942                                flags | BTRFS_EXTENT_FLAG_DATA);
7943
7944         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7945         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7946         if (parent > 0) {
7947                 struct btrfs_shared_data_ref *ref;
7948                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7949                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7950                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7951         } else {
7952                 struct btrfs_extent_data_ref *ref;
7953                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7954                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7955                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7956                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7957                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7958         }
7959
7960         btrfs_mark_buffer_dirty(path->nodes[0]);
7961         btrfs_free_path(path);
7962
7963         ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
7964         if (ret)
7965                 return ret;
7966
7967         ret = update_block_group(trans, fs_info, ins->objectid, ins->offset, 1);
7968         if (ret) { /* -ENOENT, logic error */
7969                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7970                         ins->objectid, ins->offset);
7971                 BUG();
7972         }
7973         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
7974         return ret;
7975 }
7976
7977 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7978                                      struct btrfs_delayed_ref_node *node,
7979                                      struct btrfs_delayed_extent_op *extent_op)
7980 {
7981         struct btrfs_fs_info *fs_info = trans->fs_info;
7982         int ret;
7983         struct btrfs_extent_item *extent_item;
7984         struct btrfs_key extent_key;
7985         struct btrfs_tree_block_info *block_info;
7986         struct btrfs_extent_inline_ref *iref;
7987         struct btrfs_path *path;
7988         struct extent_buffer *leaf;
7989         struct btrfs_delayed_tree_ref *ref;
7990         u32 size = sizeof(*extent_item) + sizeof(*iref);
7991         u64 num_bytes;
7992         u64 flags = extent_op->flags_to_set;
7993         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
7994
7995         ref = btrfs_delayed_node_to_tree_ref(node);
7996
7997         extent_key.objectid = node->bytenr;
7998         if (skinny_metadata) {
7999                 extent_key.offset = ref->level;
8000                 extent_key.type = BTRFS_METADATA_ITEM_KEY;
8001                 num_bytes = fs_info->nodesize;
8002         } else {
8003                 extent_key.offset = node->num_bytes;
8004                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
8005                 size += sizeof(*block_info);
8006                 num_bytes = node->num_bytes;
8007         }
8008
8009         path = btrfs_alloc_path();
8010         if (!path)
8011                 return -ENOMEM;
8012
8013         path->leave_spinning = 1;
8014         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8015                                       &extent_key, size);
8016         if (ret) {
8017                 btrfs_free_path(path);
8018                 return ret;
8019         }
8020
8021         leaf = path->nodes[0];
8022         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8023                                      struct btrfs_extent_item);
8024         btrfs_set_extent_refs(leaf, extent_item, 1);
8025         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8026         btrfs_set_extent_flags(leaf, extent_item,
8027                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8028
8029         if (skinny_metadata) {
8030                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8031         } else {
8032                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8033                 btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
8034                 btrfs_set_tree_block_level(leaf, block_info, ref->level);
8035                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8036         }
8037
8038         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
8039                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8040                 btrfs_set_extent_inline_ref_type(leaf, iref,
8041                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8042                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
8043         } else {
8044                 btrfs_set_extent_inline_ref_type(leaf, iref,
8045                                                  BTRFS_TREE_BLOCK_REF_KEY);
8046                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
8047         }
8048
8049         btrfs_mark_buffer_dirty(leaf);
8050         btrfs_free_path(path);
8051
8052         ret = remove_from_free_space_tree(trans, extent_key.objectid,
8053                                           num_bytes);
8054         if (ret)
8055                 return ret;
8056
8057         ret = update_block_group(trans, fs_info, extent_key.objectid,
8058                                  fs_info->nodesize, 1);
8059         if (ret) { /* -ENOENT, logic error */
8060                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8061                         extent_key.objectid, extent_key.offset);
8062                 BUG();
8063         }
8064
8065         trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
8066                                           fs_info->nodesize);
8067         return ret;
8068 }
8069
8070 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8071                                      struct btrfs_root *root, u64 owner,
8072                                      u64 offset, u64 ram_bytes,
8073                                      struct btrfs_key *ins)
8074 {
8075         int ret;
8076
8077         BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
8078
8079         btrfs_ref_tree_mod(root, ins->objectid, ins->offset, 0,
8080                            root->root_key.objectid, owner, offset,
8081                            BTRFS_ADD_DELAYED_EXTENT);
8082
8083         ret = btrfs_add_delayed_data_ref(trans, ins->objectid,
8084                                          ins->offset, 0,
8085                                          root->root_key.objectid, owner,
8086                                          offset, ram_bytes,
8087                                          BTRFS_ADD_DELAYED_EXTENT, NULL, NULL);
8088         return ret;
8089 }
8090
8091 /*
8092  * this is used by the tree logging recovery code.  It records that
8093  * an extent has been allocated and makes sure to clear the free
8094  * space cache bits as well
8095  */
8096 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8097                                    u64 root_objectid, u64 owner, u64 offset,
8098                                    struct btrfs_key *ins)
8099 {
8100         struct btrfs_fs_info *fs_info = trans->fs_info;
8101         int ret;
8102         struct btrfs_block_group_cache *block_group;
8103         struct btrfs_space_info *space_info;
8104
8105         /*
8106          * Mixed block groups will exclude before processing the log so we only
8107          * need to do the exclude dance if this fs isn't mixed.
8108          */
8109         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
8110                 ret = __exclude_logged_extent(fs_info, ins->objectid,
8111                                               ins->offset);
8112                 if (ret)
8113                         return ret;
8114         }
8115
8116         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
8117         if (!block_group)
8118                 return -EINVAL;
8119
8120         space_info = block_group->space_info;
8121         spin_lock(&space_info->lock);
8122         spin_lock(&block_group->lock);
8123         space_info->bytes_reserved += ins->offset;
8124         block_group->reserved += ins->offset;
8125         spin_unlock(&block_group->lock);
8126         spin_unlock(&space_info->lock);
8127
8128         ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
8129                                          offset, ins, 1);
8130         btrfs_put_block_group(block_group);
8131         return ret;
8132 }
8133
8134 static struct extent_buffer *
8135 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8136                       u64 bytenr, int level, u64 owner)
8137 {
8138         struct btrfs_fs_info *fs_info = root->fs_info;
8139         struct extent_buffer *buf;
8140
8141         buf = btrfs_find_create_tree_block(fs_info, bytenr);
8142         if (IS_ERR(buf))
8143                 return buf;
8144
8145         /*
8146          * Extra safety check in case the extent tree is corrupted and extent
8147          * allocator chooses to use a tree block which is already used and
8148          * locked.
8149          */
8150         if (buf->lock_owner == current->pid) {
8151                 btrfs_err_rl(fs_info,
8152 "tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
8153                         buf->start, btrfs_header_owner(buf), current->pid);
8154                 free_extent_buffer(buf);
8155                 return ERR_PTR(-EUCLEAN);
8156         }
8157
8158         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8159         btrfs_tree_lock(buf);
8160         clean_tree_block(fs_info, buf);
8161         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8162
8163         btrfs_set_lock_blocking(buf);
8164         set_extent_buffer_uptodate(buf);
8165
8166         memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
8167         btrfs_set_header_level(buf, level);
8168         btrfs_set_header_bytenr(buf, buf->start);
8169         btrfs_set_header_generation(buf, trans->transid);
8170         btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
8171         btrfs_set_header_owner(buf, owner);
8172         write_extent_buffer_fsid(buf, fs_info->fsid);
8173         write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
8174         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8175                 buf->log_index = root->log_transid % 2;
8176                 /*
8177                  * we allow two log transactions at a time, use different
8178                  * EXENT bit to differentiate dirty pages.
8179                  */
8180                 if (buf->log_index == 0)
8181                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8182                                         buf->start + buf->len - 1, GFP_NOFS);
8183                 else
8184                         set_extent_new(&root->dirty_log_pages, buf->start,
8185                                         buf->start + buf->len - 1);
8186         } else {
8187                 buf->log_index = -1;
8188                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8189                          buf->start + buf->len - 1, GFP_NOFS);
8190         }
8191         trans->dirty = true;
8192         /* this returns a buffer locked for blocking */
8193         return buf;
8194 }
8195
8196 static struct btrfs_block_rsv *
8197 use_block_rsv(struct btrfs_trans_handle *trans,
8198               struct btrfs_root *root, u32 blocksize)
8199 {
8200         struct btrfs_fs_info *fs_info = root->fs_info;
8201         struct btrfs_block_rsv *block_rsv;
8202         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
8203         int ret;
8204         bool global_updated = false;
8205
8206         block_rsv = get_block_rsv(trans, root);
8207
8208         if (unlikely(block_rsv->size == 0))
8209                 goto try_reserve;
8210 again:
8211         ret = block_rsv_use_bytes(block_rsv, blocksize);
8212         if (!ret)
8213                 return block_rsv;
8214
8215         if (block_rsv->failfast)
8216                 return ERR_PTR(ret);
8217
8218         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8219                 global_updated = true;
8220                 update_global_block_rsv(fs_info);
8221                 goto again;
8222         }
8223
8224         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8225                 static DEFINE_RATELIMIT_STATE(_rs,
8226                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8227                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8228                 if (__ratelimit(&_rs))
8229                         WARN(1, KERN_DEBUG
8230                                 "BTRFS: block rsv returned %d\n", ret);
8231         }
8232 try_reserve:
8233         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8234                                      BTRFS_RESERVE_NO_FLUSH);
8235         if (!ret)
8236                 return block_rsv;
8237         /*
8238          * If we couldn't reserve metadata bytes try and use some from
8239          * the global reserve if its space type is the same as the global
8240          * reservation.
8241          */
8242         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8243             block_rsv->space_info == global_rsv->space_info) {
8244                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8245                 if (!ret)
8246                         return global_rsv;
8247         }
8248         return ERR_PTR(ret);
8249 }
8250
8251 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8252                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8253 {
8254         block_rsv_add_bytes(block_rsv, blocksize, false);
8255         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0, NULL);
8256 }
8257
8258 /*
8259  * finds a free extent and does all the dirty work required for allocation
8260  * returns the tree buffer or an ERR_PTR on error.
8261  */
8262 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8263                                              struct btrfs_root *root,
8264                                              u64 parent, u64 root_objectid,
8265                                              const struct btrfs_disk_key *key,
8266                                              int level, u64 hint,
8267                                              u64 empty_size)
8268 {
8269         struct btrfs_fs_info *fs_info = root->fs_info;
8270         struct btrfs_key ins;
8271         struct btrfs_block_rsv *block_rsv;
8272         struct extent_buffer *buf;
8273         struct btrfs_delayed_extent_op *extent_op;
8274         u64 flags = 0;
8275         int ret;
8276         u32 blocksize = fs_info->nodesize;
8277         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8278
8279 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8280         if (btrfs_is_testing(fs_info)) {
8281                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8282                                             level, root_objectid);
8283                 if (!IS_ERR(buf))
8284                         root->alloc_bytenr += blocksize;
8285                 return buf;
8286         }
8287 #endif
8288
8289         block_rsv = use_block_rsv(trans, root, blocksize);
8290         if (IS_ERR(block_rsv))
8291                 return ERR_CAST(block_rsv);
8292
8293         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8294                                    empty_size, hint, &ins, 0, 0);
8295         if (ret)
8296                 goto out_unuse;
8297
8298         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
8299                                     root_objectid);
8300         if (IS_ERR(buf)) {
8301                 ret = PTR_ERR(buf);
8302                 goto out_free_reserved;
8303         }
8304
8305         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8306                 if (parent == 0)
8307                         parent = ins.objectid;
8308                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8309         } else
8310                 BUG_ON(parent > 0);
8311
8312         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8313                 extent_op = btrfs_alloc_delayed_extent_op();
8314                 if (!extent_op) {
8315                         ret = -ENOMEM;
8316                         goto out_free_buf;
8317                 }
8318                 if (key)
8319                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8320                 else
8321                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8322                 extent_op->flags_to_set = flags;
8323                 extent_op->update_key = skinny_metadata ? false : true;
8324                 extent_op->update_flags = true;
8325                 extent_op->is_data = false;
8326                 extent_op->level = level;
8327
8328                 btrfs_ref_tree_mod(root, ins.objectid, ins.offset, parent,
8329                                    root_objectid, level, 0,
8330                                    BTRFS_ADD_DELAYED_EXTENT);
8331                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
8332                                                  ins.offset, parent,
8333                                                  root_objectid, level,
8334                                                  BTRFS_ADD_DELAYED_EXTENT,
8335                                                  extent_op, NULL, NULL);
8336                 if (ret)
8337                         goto out_free_delayed;
8338         }
8339         return buf;
8340
8341 out_free_delayed:
8342         btrfs_free_delayed_extent_op(extent_op);
8343 out_free_buf:
8344         free_extent_buffer(buf);
8345 out_free_reserved:
8346         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
8347 out_unuse:
8348         unuse_block_rsv(fs_info, block_rsv, blocksize);
8349         return ERR_PTR(ret);
8350 }
8351
8352 struct walk_control {
8353         u64 refs[BTRFS_MAX_LEVEL];
8354         u64 flags[BTRFS_MAX_LEVEL];
8355         struct btrfs_key update_progress;
8356         int stage;
8357         int level;
8358         int shared_level;
8359         int update_ref;
8360         int keep_locks;
8361         int reada_slot;
8362         int reada_count;
8363 };
8364
8365 #define DROP_REFERENCE  1
8366 #define UPDATE_BACKREF  2
8367
8368 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8369                                      struct btrfs_root *root,
8370                                      struct walk_control *wc,
8371                                      struct btrfs_path *path)
8372 {
8373         struct btrfs_fs_info *fs_info = root->fs_info;
8374         u64 bytenr;
8375         u64 generation;
8376         u64 refs;
8377         u64 flags;
8378         u32 nritems;
8379         struct btrfs_key key;
8380         struct extent_buffer *eb;
8381         int ret;
8382         int slot;
8383         int nread = 0;
8384
8385         if (path->slots[wc->level] < wc->reada_slot) {
8386                 wc->reada_count = wc->reada_count * 2 / 3;
8387                 wc->reada_count = max(wc->reada_count, 2);
8388         } else {
8389                 wc->reada_count = wc->reada_count * 3 / 2;
8390                 wc->reada_count = min_t(int, wc->reada_count,
8391                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
8392         }
8393
8394         eb = path->nodes[wc->level];
8395         nritems = btrfs_header_nritems(eb);
8396
8397         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8398                 if (nread >= wc->reada_count)
8399                         break;
8400
8401                 cond_resched();
8402                 bytenr = btrfs_node_blockptr(eb, slot);
8403                 generation = btrfs_node_ptr_generation(eb, slot);
8404
8405                 if (slot == path->slots[wc->level])
8406                         goto reada;
8407
8408                 if (wc->stage == UPDATE_BACKREF &&
8409                     generation <= root->root_key.offset)
8410                         continue;
8411
8412                 /* We don't lock the tree block, it's OK to be racy here */
8413                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
8414                                                wc->level - 1, 1, &refs,
8415                                                &flags);
8416                 /* We don't care about errors in readahead. */
8417                 if (ret < 0)
8418                         continue;
8419                 BUG_ON(refs == 0);
8420
8421                 if (wc->stage == DROP_REFERENCE) {
8422                         if (refs == 1)
8423                                 goto reada;
8424
8425                         if (wc->level == 1 &&
8426                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8427                                 continue;
8428                         if (!wc->update_ref ||
8429                             generation <= root->root_key.offset)
8430                                 continue;
8431                         btrfs_node_key_to_cpu(eb, &key, slot);
8432                         ret = btrfs_comp_cpu_keys(&key,
8433                                                   &wc->update_progress);
8434                         if (ret < 0)
8435                                 continue;
8436                 } else {
8437                         if (wc->level == 1 &&
8438                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8439                                 continue;
8440                 }
8441 reada:
8442                 readahead_tree_block(fs_info, bytenr);
8443                 nread++;
8444         }
8445         wc->reada_slot = slot;
8446 }
8447
8448 /*
8449  * helper to process tree block while walking down the tree.
8450  *
8451  * when wc->stage == UPDATE_BACKREF, this function updates
8452  * back refs for pointers in the block.
8453  *
8454  * NOTE: return value 1 means we should stop walking down.
8455  */
8456 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8457                                    struct btrfs_root *root,
8458                                    struct btrfs_path *path,
8459                                    struct walk_control *wc, int lookup_info)
8460 {
8461         struct btrfs_fs_info *fs_info = root->fs_info;
8462         int level = wc->level;
8463         struct extent_buffer *eb = path->nodes[level];
8464         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8465         int ret;
8466
8467         if (wc->stage == UPDATE_BACKREF &&
8468             btrfs_header_owner(eb) != root->root_key.objectid)
8469                 return 1;
8470
8471         /*
8472          * when reference count of tree block is 1, it won't increase
8473          * again. once full backref flag is set, we never clear it.
8474          */
8475         if (lookup_info &&
8476             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8477              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8478                 BUG_ON(!path->locks[level]);
8479                 ret = btrfs_lookup_extent_info(trans, fs_info,
8480                                                eb->start, level, 1,
8481                                                &wc->refs[level],
8482                                                &wc->flags[level]);
8483                 BUG_ON(ret == -ENOMEM);
8484                 if (ret)
8485                         return ret;
8486                 BUG_ON(wc->refs[level] == 0);
8487         }
8488
8489         if (wc->stage == DROP_REFERENCE) {
8490                 if (wc->refs[level] > 1)
8491                         return 1;
8492
8493                 if (path->locks[level] && !wc->keep_locks) {
8494                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8495                         path->locks[level] = 0;
8496                 }
8497                 return 0;
8498         }
8499
8500         /* wc->stage == UPDATE_BACKREF */
8501         if (!(wc->flags[level] & flag)) {
8502                 BUG_ON(!path->locks[level]);
8503                 ret = btrfs_inc_ref(trans, root, eb, 1);
8504                 BUG_ON(ret); /* -ENOMEM */
8505                 ret = btrfs_dec_ref(trans, root, eb, 0);
8506                 BUG_ON(ret); /* -ENOMEM */
8507                 ret = btrfs_set_disk_extent_flags(trans, fs_info, eb->start,
8508                                                   eb->len, flag,
8509                                                   btrfs_header_level(eb), 0);
8510                 BUG_ON(ret); /* -ENOMEM */
8511                 wc->flags[level] |= flag;
8512         }
8513
8514         /*
8515          * the block is shared by multiple trees, so it's not good to
8516          * keep the tree lock
8517          */
8518         if (path->locks[level] && level > 0) {
8519                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8520                 path->locks[level] = 0;
8521         }
8522         return 0;
8523 }
8524
8525 /*
8526  * helper to process tree block pointer.
8527  *
8528  * when wc->stage == DROP_REFERENCE, this function checks
8529  * reference count of the block pointed to. if the block
8530  * is shared and we need update back refs for the subtree
8531  * rooted at the block, this function changes wc->stage to
8532  * UPDATE_BACKREF. if the block is shared and there is no
8533  * need to update back, this function drops the reference
8534  * to the block.
8535  *
8536  * NOTE: return value 1 means we should stop walking down.
8537  */
8538 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8539                                  struct btrfs_root *root,
8540                                  struct btrfs_path *path,
8541                                  struct walk_control *wc, int *lookup_info)
8542 {
8543         struct btrfs_fs_info *fs_info = root->fs_info;
8544         u64 bytenr;
8545         u64 generation;
8546         u64 parent;
8547         u32 blocksize;
8548         struct btrfs_key key;
8549         struct btrfs_key first_key;
8550         struct extent_buffer *next;
8551         int level = wc->level;
8552         int reada = 0;
8553         int ret = 0;
8554         bool need_account = false;
8555
8556         generation = btrfs_node_ptr_generation(path->nodes[level],
8557                                                path->slots[level]);
8558         /*
8559          * if the lower level block was created before the snapshot
8560          * was created, we know there is no need to update back refs
8561          * for the subtree
8562          */
8563         if (wc->stage == UPDATE_BACKREF &&
8564             generation <= root->root_key.offset) {
8565                 *lookup_info = 1;
8566                 return 1;
8567         }
8568
8569         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8570         btrfs_node_key_to_cpu(path->nodes[level], &first_key,
8571                               path->slots[level]);
8572         blocksize = fs_info->nodesize;
8573
8574         next = find_extent_buffer(fs_info, bytenr);
8575         if (!next) {
8576                 next = btrfs_find_create_tree_block(fs_info, bytenr);
8577                 if (IS_ERR(next))
8578                         return PTR_ERR(next);
8579
8580                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8581                                                level - 1);
8582                 reada = 1;
8583         }
8584         btrfs_tree_lock(next);
8585         btrfs_set_lock_blocking(next);
8586
8587         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
8588                                        &wc->refs[level - 1],
8589                                        &wc->flags[level - 1]);
8590         if (ret < 0)
8591                 goto out_unlock;
8592
8593         if (unlikely(wc->refs[level - 1] == 0)) {
8594                 btrfs_err(fs_info, "Missing references.");
8595                 ret = -EIO;
8596                 goto out_unlock;
8597         }
8598         *lookup_info = 0;
8599
8600         if (wc->stage == DROP_REFERENCE) {
8601                 if (wc->refs[level - 1] > 1) {
8602                         need_account = true;
8603                         if (level == 1 &&
8604                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8605                                 goto skip;
8606
8607                         if (!wc->update_ref ||
8608                             generation <= root->root_key.offset)
8609                                 goto skip;
8610
8611                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8612                                               path->slots[level]);
8613                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8614                         if (ret < 0)
8615                                 goto skip;
8616
8617                         wc->stage = UPDATE_BACKREF;
8618                         wc->shared_level = level - 1;
8619                 }
8620         } else {
8621                 if (level == 1 &&
8622                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8623                         goto skip;
8624         }
8625
8626         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8627                 btrfs_tree_unlock(next);
8628                 free_extent_buffer(next);
8629                 next = NULL;
8630                 *lookup_info = 1;
8631         }
8632
8633         if (!next) {
8634                 if (reada && level == 1)
8635                         reada_walk_down(trans, root, wc, path);
8636                 next = read_tree_block(fs_info, bytenr, generation, level - 1,
8637                                        &first_key);
8638                 if (IS_ERR(next)) {
8639                         return PTR_ERR(next);
8640                 } else if (!extent_buffer_uptodate(next)) {
8641                         free_extent_buffer(next);
8642                         return -EIO;
8643                 }
8644                 btrfs_tree_lock(next);
8645                 btrfs_set_lock_blocking(next);
8646         }
8647
8648         level--;
8649         ASSERT(level == btrfs_header_level(next));
8650         if (level != btrfs_header_level(next)) {
8651                 btrfs_err(root->fs_info, "mismatched level");
8652                 ret = -EIO;
8653                 goto out_unlock;
8654         }
8655         path->nodes[level] = next;
8656         path->slots[level] = 0;
8657         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8658         wc->level = level;
8659         if (wc->level == 1)
8660                 wc->reada_slot = 0;
8661         return 0;
8662 skip:
8663         wc->refs[level - 1] = 0;
8664         wc->flags[level - 1] = 0;
8665         if (wc->stage == DROP_REFERENCE) {
8666                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8667                         parent = path->nodes[level]->start;
8668                 } else {
8669                         ASSERT(root->root_key.objectid ==
8670                                btrfs_header_owner(path->nodes[level]));
8671                         if (root->root_key.objectid !=
8672                             btrfs_header_owner(path->nodes[level])) {
8673                                 btrfs_err(root->fs_info,
8674                                                 "mismatched block owner");
8675                                 ret = -EIO;
8676                                 goto out_unlock;
8677                         }
8678                         parent = 0;
8679                 }
8680
8681                 /*
8682                  * Reloc tree doesn't contribute to qgroup numbers, and we have
8683                  * already accounted them at merge time (replace_path),
8684                  * thus we could skip expensive subtree trace here.
8685                  */
8686                 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
8687                     need_account) {
8688                         ret = btrfs_qgroup_trace_subtree(trans, next,
8689                                                          generation, level - 1);
8690                         if (ret) {
8691                                 btrfs_err_rl(fs_info,
8692                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8693                                              ret);
8694                         }
8695                 }
8696                 ret = btrfs_free_extent(trans, root, bytenr, blocksize,
8697                                         parent, root->root_key.objectid,
8698                                         level - 1, 0);
8699                 if (ret)
8700                         goto out_unlock;
8701         }
8702
8703         *lookup_info = 1;
8704         ret = 1;
8705
8706 out_unlock:
8707         btrfs_tree_unlock(next);
8708         free_extent_buffer(next);
8709
8710         return ret;
8711 }
8712
8713 /*
8714  * helper to process tree block while walking up the tree.
8715  *
8716  * when wc->stage == DROP_REFERENCE, this function drops
8717  * reference count on the block.
8718  *
8719  * when wc->stage == UPDATE_BACKREF, this function changes
8720  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8721  * to UPDATE_BACKREF previously while processing the block.
8722  *
8723  * NOTE: return value 1 means we should stop walking up.
8724  */
8725 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8726                                  struct btrfs_root *root,
8727                                  struct btrfs_path *path,
8728                                  struct walk_control *wc)
8729 {
8730         struct btrfs_fs_info *fs_info = root->fs_info;
8731         int ret;
8732         int level = wc->level;
8733         struct extent_buffer *eb = path->nodes[level];
8734         u64 parent = 0;
8735
8736         if (wc->stage == UPDATE_BACKREF) {
8737                 BUG_ON(wc->shared_level < level);
8738                 if (level < wc->shared_level)
8739                         goto out;
8740
8741                 ret = find_next_key(path, level + 1, &wc->update_progress);
8742                 if (ret > 0)
8743                         wc->update_ref = 0;
8744
8745                 wc->stage = DROP_REFERENCE;
8746                 wc->shared_level = -1;
8747                 path->slots[level] = 0;
8748
8749                 /*
8750                  * check reference count again if the block isn't locked.
8751                  * we should start walking down the tree again if reference
8752                  * count is one.
8753                  */
8754                 if (!path->locks[level]) {
8755                         BUG_ON(level == 0);
8756                         btrfs_tree_lock(eb);
8757                         btrfs_set_lock_blocking(eb);
8758                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8759
8760                         ret = btrfs_lookup_extent_info(trans, fs_info,
8761                                                        eb->start, level, 1,
8762                                                        &wc->refs[level],
8763                                                        &wc->flags[level]);
8764                         if (ret < 0) {
8765                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8766                                 path->locks[level] = 0;
8767                                 return ret;
8768                         }
8769                         BUG_ON(wc->refs[level] == 0);
8770                         if (wc->refs[level] == 1) {
8771                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8772                                 path->locks[level] = 0;
8773                                 return 1;
8774                         }
8775                 }
8776         }
8777
8778         /* wc->stage == DROP_REFERENCE */
8779         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8780
8781         if (wc->refs[level] == 1) {
8782                 if (level == 0) {
8783                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8784                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8785                         else
8786                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8787                         BUG_ON(ret); /* -ENOMEM */
8788                         ret = btrfs_qgroup_trace_leaf_items(trans, eb);
8789                         if (ret) {
8790                                 btrfs_err_rl(fs_info,
8791                                              "error %d accounting leaf items. Quota is out of sync, rescan required.",
8792                                              ret);
8793                         }
8794                 }
8795                 /* make block locked assertion in clean_tree_block happy */
8796                 if (!path->locks[level] &&
8797                     btrfs_header_generation(eb) == trans->transid) {
8798                         btrfs_tree_lock(eb);
8799                         btrfs_set_lock_blocking(eb);
8800                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8801                 }
8802                 clean_tree_block(fs_info, eb);
8803         }
8804
8805         if (eb == root->node) {
8806                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8807                         parent = eb->start;
8808                 else if (root->root_key.objectid != btrfs_header_owner(eb))
8809                         goto owner_mismatch;
8810         } else {
8811                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8812                         parent = path->nodes[level + 1]->start;
8813                 else if (root->root_key.objectid !=
8814                          btrfs_header_owner(path->nodes[level + 1]))
8815                         goto owner_mismatch;
8816         }
8817
8818         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8819 out:
8820         wc->refs[level] = 0;
8821         wc->flags[level] = 0;
8822         return 0;
8823
8824 owner_mismatch:
8825         btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
8826                      btrfs_header_owner(eb), root->root_key.objectid);
8827         return -EUCLEAN;
8828 }
8829
8830 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8831                                    struct btrfs_root *root,
8832                                    struct btrfs_path *path,
8833                                    struct walk_control *wc)
8834 {
8835         int level = wc->level;
8836         int lookup_info = 1;
8837         int ret;
8838
8839         while (level >= 0) {
8840                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8841                 if (ret > 0)
8842                         break;
8843
8844                 if (level == 0)
8845                         break;
8846
8847                 if (path->slots[level] >=
8848                     btrfs_header_nritems(path->nodes[level]))
8849                         break;
8850
8851                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8852                 if (ret > 0) {
8853                         path->slots[level]++;
8854                         continue;
8855                 } else if (ret < 0)
8856                         return ret;
8857                 level = wc->level;
8858         }
8859         return 0;
8860 }
8861
8862 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8863                                  struct btrfs_root *root,
8864                                  struct btrfs_path *path,
8865                                  struct walk_control *wc, int max_level)
8866 {
8867         int level = wc->level;
8868         int ret;
8869
8870         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8871         while (level < max_level && path->nodes[level]) {
8872                 wc->level = level;
8873                 if (path->slots[level] + 1 <
8874                     btrfs_header_nritems(path->nodes[level])) {
8875                         path->slots[level]++;
8876                         return 0;
8877                 } else {
8878                         ret = walk_up_proc(trans, root, path, wc);
8879                         if (ret > 0)
8880                                 return 0;
8881                         if (ret < 0)
8882                                 return ret;
8883
8884                         if (path->locks[level]) {
8885                                 btrfs_tree_unlock_rw(path->nodes[level],
8886                                                      path->locks[level]);
8887                                 path->locks[level] = 0;
8888                         }
8889                         free_extent_buffer(path->nodes[level]);
8890                         path->nodes[level] = NULL;
8891                         level++;
8892                 }
8893         }
8894         return 1;
8895 }
8896
8897 /*
8898  * drop a subvolume tree.
8899  *
8900  * this function traverses the tree freeing any blocks that only
8901  * referenced by the tree.
8902  *
8903  * when a shared tree block is found. this function decreases its
8904  * reference count by one. if update_ref is true, this function
8905  * also make sure backrefs for the shared block and all lower level
8906  * blocks are properly updated.
8907  *
8908  * If called with for_reloc == 0, may exit early with -EAGAIN
8909  */
8910 int btrfs_drop_snapshot(struct btrfs_root *root,
8911                          struct btrfs_block_rsv *block_rsv, int update_ref,
8912                          int for_reloc)
8913 {
8914         struct btrfs_fs_info *fs_info = root->fs_info;
8915         struct btrfs_path *path;
8916         struct btrfs_trans_handle *trans;
8917         struct btrfs_root *tree_root = fs_info->tree_root;
8918         struct btrfs_root_item *root_item = &root->root_item;
8919         struct walk_control *wc;
8920         struct btrfs_key key;
8921         int err = 0;
8922         int ret;
8923         int level;
8924         bool root_dropped = false;
8925
8926         btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
8927
8928         path = btrfs_alloc_path();
8929         if (!path) {
8930                 err = -ENOMEM;
8931                 goto out;
8932         }
8933
8934         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8935         if (!wc) {
8936                 btrfs_free_path(path);
8937                 err = -ENOMEM;
8938                 goto out;
8939         }
8940
8941         trans = btrfs_start_transaction(tree_root, 0);
8942         if (IS_ERR(trans)) {
8943                 err = PTR_ERR(trans);
8944                 goto out_free;
8945         }
8946
8947         if (block_rsv)
8948                 trans->block_rsv = block_rsv;
8949
8950         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8951                 level = btrfs_header_level(root->node);
8952                 path->nodes[level] = btrfs_lock_root_node(root);
8953                 btrfs_set_lock_blocking(path->nodes[level]);
8954                 path->slots[level] = 0;
8955                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8956                 memset(&wc->update_progress, 0,
8957                        sizeof(wc->update_progress));
8958         } else {
8959                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8960                 memcpy(&wc->update_progress, &key,
8961                        sizeof(wc->update_progress));
8962
8963                 level = root_item->drop_level;
8964                 BUG_ON(level == 0);
8965                 path->lowest_level = level;
8966                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8967                 path->lowest_level = 0;
8968                 if (ret < 0) {
8969                         err = ret;
8970                         goto out_end_trans;
8971                 }
8972                 WARN_ON(ret > 0);
8973
8974                 /*
8975                  * unlock our path, this is safe because only this
8976                  * function is allowed to delete this snapshot
8977                  */
8978                 btrfs_unlock_up_safe(path, 0);
8979
8980                 level = btrfs_header_level(root->node);
8981                 while (1) {
8982                         btrfs_tree_lock(path->nodes[level]);
8983                         btrfs_set_lock_blocking(path->nodes[level]);
8984                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8985
8986                         ret = btrfs_lookup_extent_info(trans, fs_info,
8987                                                 path->nodes[level]->start,
8988                                                 level, 1, &wc->refs[level],
8989                                                 &wc->flags[level]);
8990                         if (ret < 0) {
8991                                 err = ret;
8992                                 goto out_end_trans;
8993                         }
8994                         BUG_ON(wc->refs[level] == 0);
8995
8996                         if (level == root_item->drop_level)
8997                                 break;
8998
8999                         btrfs_tree_unlock(path->nodes[level]);
9000                         path->locks[level] = 0;
9001                         WARN_ON(wc->refs[level] != 1);
9002                         level--;
9003                 }
9004         }
9005
9006         wc->level = level;
9007         wc->shared_level = -1;
9008         wc->stage = DROP_REFERENCE;
9009         wc->update_ref = update_ref;
9010         wc->keep_locks = 0;
9011         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9012
9013         while (1) {
9014
9015                 ret = walk_down_tree(trans, root, path, wc);
9016                 if (ret < 0) {
9017                         err = ret;
9018                         break;
9019                 }
9020
9021                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9022                 if (ret < 0) {
9023                         err = ret;
9024                         break;
9025                 }
9026
9027                 if (ret > 0) {
9028                         BUG_ON(wc->stage != DROP_REFERENCE);
9029                         break;
9030                 }
9031
9032                 if (wc->stage == DROP_REFERENCE) {
9033                         level = wc->level;
9034                         btrfs_node_key(path->nodes[level],
9035                                        &root_item->drop_progress,
9036                                        path->slots[level]);
9037                         root_item->drop_level = level;
9038                 }
9039
9040                 BUG_ON(wc->level == 0);
9041                 if (btrfs_should_end_transaction(trans) ||
9042                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
9043                         ret = btrfs_update_root(trans, tree_root,
9044                                                 &root->root_key,
9045                                                 root_item);
9046                         if (ret) {
9047                                 btrfs_abort_transaction(trans, ret);
9048                                 err = ret;
9049                                 goto out_end_trans;
9050                         }
9051
9052                         btrfs_end_transaction_throttle(trans);
9053                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
9054                                 btrfs_debug(fs_info,
9055                                             "drop snapshot early exit");
9056                                 err = -EAGAIN;
9057                                 goto out_free;
9058                         }
9059
9060                         trans = btrfs_start_transaction(tree_root, 0);
9061                         if (IS_ERR(trans)) {
9062                                 err = PTR_ERR(trans);
9063                                 goto out_free;
9064                         }
9065                         if (block_rsv)
9066                                 trans->block_rsv = block_rsv;
9067                 }
9068         }
9069         btrfs_release_path(path);
9070         if (err)
9071                 goto out_end_trans;
9072
9073         ret = btrfs_del_root(trans, &root->root_key);
9074         if (ret) {
9075                 btrfs_abort_transaction(trans, ret);
9076                 err = ret;
9077                 goto out_end_trans;
9078         }
9079
9080         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9081                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9082                                       NULL, NULL);
9083                 if (ret < 0) {
9084                         btrfs_abort_transaction(trans, ret);
9085                         err = ret;
9086                         goto out_end_trans;
9087                 } else if (ret > 0) {
9088                         /* if we fail to delete the orphan item this time
9089                          * around, it'll get picked up the next time.
9090                          *
9091                          * The most common failure here is just -ENOENT.
9092                          */
9093                         btrfs_del_orphan_item(trans, tree_root,
9094                                               root->root_key.objectid);
9095                 }
9096         }
9097
9098         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9099                 btrfs_add_dropped_root(trans, root);
9100         } else {
9101                 free_extent_buffer(root->node);
9102                 free_extent_buffer(root->commit_root);
9103                 btrfs_put_fs_root(root);
9104         }
9105         root_dropped = true;
9106 out_end_trans:
9107         btrfs_end_transaction_throttle(trans);
9108 out_free:
9109         kfree(wc);
9110         btrfs_free_path(path);
9111 out:
9112         /*
9113          * So if we need to stop dropping the snapshot for whatever reason we
9114          * need to make sure to add it back to the dead root list so that we
9115          * keep trying to do the work later.  This also cleans up roots if we
9116          * don't have it in the radix (like when we recover after a power fail
9117          * or unmount) so we don't leak memory.
9118          */
9119         if (!for_reloc && !root_dropped)
9120                 btrfs_add_dead_root(root);
9121         if (err && err != -EAGAIN)
9122                 btrfs_handle_fs_error(fs_info, err, NULL);
9123         return err;
9124 }
9125
9126 /*
9127  * drop subtree rooted at tree block 'node'.
9128  *
9129  * NOTE: this function will unlock and release tree block 'node'
9130  * only used by relocation code
9131  */
9132 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9133                         struct btrfs_root *root,
9134                         struct extent_buffer *node,
9135                         struct extent_buffer *parent)
9136 {
9137         struct btrfs_fs_info *fs_info = root->fs_info;
9138         struct btrfs_path *path;
9139         struct walk_control *wc;
9140         int level;
9141         int parent_level;
9142         int ret = 0;
9143         int wret;
9144
9145         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9146
9147         path = btrfs_alloc_path();
9148         if (!path)
9149                 return -ENOMEM;
9150
9151         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9152         if (!wc) {
9153                 btrfs_free_path(path);
9154                 return -ENOMEM;
9155         }
9156
9157         btrfs_assert_tree_locked(parent);
9158         parent_level = btrfs_header_level(parent);
9159         extent_buffer_get(parent);
9160         path->nodes[parent_level] = parent;
9161         path->slots[parent_level] = btrfs_header_nritems(parent);
9162
9163         btrfs_assert_tree_locked(node);
9164         level = btrfs_header_level(node);
9165         path->nodes[level] = node;
9166         path->slots[level] = 0;
9167         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9168
9169         wc->refs[parent_level] = 1;
9170         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9171         wc->level = level;
9172         wc->shared_level = -1;
9173         wc->stage = DROP_REFERENCE;
9174         wc->update_ref = 0;
9175         wc->keep_locks = 1;
9176         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9177
9178         while (1) {
9179                 wret = walk_down_tree(trans, root, path, wc);
9180                 if (wret < 0) {
9181                         ret = wret;
9182                         break;
9183                 }
9184
9185                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9186                 if (wret < 0)
9187                         ret = wret;
9188                 if (wret != 0)
9189                         break;
9190         }
9191
9192         kfree(wc);
9193         btrfs_free_path(path);
9194         return ret;
9195 }
9196
9197 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
9198 {
9199         u64 num_devices;
9200         u64 stripped;
9201
9202         /*
9203          * if restripe for this chunk_type is on pick target profile and
9204          * return, otherwise do the usual balance
9205          */
9206         stripped = get_restripe_target(fs_info, flags);
9207         if (stripped)
9208                 return extended_to_chunk(stripped);
9209
9210         num_devices = fs_info->fs_devices->rw_devices;
9211
9212         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9213                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9214                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9215
9216         if (num_devices == 1) {
9217                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9218                 stripped = flags & ~stripped;
9219
9220                 /* turn raid0 into single device chunks */
9221                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9222                         return stripped;
9223
9224                 /* turn mirroring into duplication */
9225                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9226                              BTRFS_BLOCK_GROUP_RAID10))
9227                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9228         } else {
9229                 /* they already had raid on here, just return */
9230                 if (flags & stripped)
9231                         return flags;
9232
9233                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9234                 stripped = flags & ~stripped;
9235
9236                 /* switch duplicated blocks with raid1 */
9237                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9238                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9239
9240                 /* this is drive concat, leave it alone */
9241         }
9242
9243         return flags;
9244 }
9245
9246 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9247 {
9248         struct btrfs_space_info *sinfo = cache->space_info;
9249         u64 num_bytes;
9250         u64 min_allocable_bytes;
9251         int ret = -ENOSPC;
9252
9253         /*
9254          * We need some metadata space and system metadata space for
9255          * allocating chunks in some corner cases until we force to set
9256          * it to be readonly.
9257          */
9258         if ((sinfo->flags &
9259              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9260             !force)
9261                 min_allocable_bytes = SZ_1M;
9262         else
9263                 min_allocable_bytes = 0;
9264
9265         spin_lock(&sinfo->lock);
9266         spin_lock(&cache->lock);
9267
9268         if (cache->ro) {
9269                 cache->ro++;
9270                 ret = 0;
9271                 goto out;
9272         }
9273
9274         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9275                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9276
9277         if (btrfs_space_info_used(sinfo, true) + num_bytes +
9278             min_allocable_bytes <= sinfo->total_bytes) {
9279                 sinfo->bytes_readonly += num_bytes;
9280                 cache->ro++;
9281                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9282                 ret = 0;
9283         }
9284 out:
9285         spin_unlock(&cache->lock);
9286         spin_unlock(&sinfo->lock);
9287         return ret;
9288 }
9289
9290 int btrfs_inc_block_group_ro(struct btrfs_block_group_cache *cache)
9291
9292 {
9293         struct btrfs_fs_info *fs_info = cache->fs_info;
9294         struct btrfs_trans_handle *trans;
9295         u64 alloc_flags;
9296         int ret;
9297
9298 again:
9299         trans = btrfs_join_transaction(fs_info->extent_root);
9300         if (IS_ERR(trans))
9301                 return PTR_ERR(trans);
9302
9303         /*
9304          * we're not allowed to set block groups readonly after the dirty
9305          * block groups cache has started writing.  If it already started,
9306          * back off and let this transaction commit
9307          */
9308         mutex_lock(&fs_info->ro_block_group_mutex);
9309         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9310                 u64 transid = trans->transid;
9311
9312                 mutex_unlock(&fs_info->ro_block_group_mutex);
9313                 btrfs_end_transaction(trans);
9314
9315                 ret = btrfs_wait_for_commit(fs_info, transid);
9316                 if (ret)
9317                         return ret;
9318                 goto again;
9319         }
9320
9321         /*
9322          * if we are changing raid levels, try to allocate a corresponding
9323          * block group with the new raid level.
9324          */
9325         alloc_flags = update_block_group_flags(fs_info, cache->flags);
9326         if (alloc_flags != cache->flags) {
9327                 ret = do_chunk_alloc(trans, alloc_flags,
9328                                      CHUNK_ALLOC_FORCE);
9329                 /*
9330                  * ENOSPC is allowed here, we may have enough space
9331                  * already allocated at the new raid level to
9332                  * carry on
9333                  */
9334                 if (ret == -ENOSPC)
9335                         ret = 0;
9336                 if (ret < 0)
9337                         goto out;
9338         }
9339
9340         ret = inc_block_group_ro(cache, 0);
9341         if (!ret)
9342                 goto out;
9343         alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
9344         ret = do_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
9345         if (ret < 0)
9346                 goto out;
9347         ret = inc_block_group_ro(cache, 0);
9348 out:
9349         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9350                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
9351                 mutex_lock(&fs_info->chunk_mutex);
9352                 check_system_chunk(trans, alloc_flags);
9353                 mutex_unlock(&fs_info->chunk_mutex);
9354         }
9355         mutex_unlock(&fs_info->ro_block_group_mutex);
9356
9357         btrfs_end_transaction(trans);
9358         return ret;
9359 }
9360
9361 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
9362 {
9363         u64 alloc_flags = get_alloc_profile(trans->fs_info, type);
9364
9365         return do_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
9366 }
9367
9368 /*
9369  * helper to account the unused space of all the readonly block group in the
9370  * space_info. takes mirrors into account.
9371  */
9372 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9373 {
9374         struct btrfs_block_group_cache *block_group;
9375         u64 free_bytes = 0;
9376         int factor;
9377
9378         /* It's df, we don't care if it's racy */
9379         if (list_empty(&sinfo->ro_bgs))
9380                 return 0;
9381
9382         spin_lock(&sinfo->lock);
9383         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9384                 spin_lock(&block_group->lock);
9385
9386                 if (!block_group->ro) {
9387                         spin_unlock(&block_group->lock);
9388                         continue;
9389                 }
9390
9391                 factor = btrfs_bg_type_to_factor(block_group->flags);
9392                 free_bytes += (block_group->key.offset -
9393                                btrfs_block_group_used(&block_group->item)) *
9394                                factor;
9395
9396                 spin_unlock(&block_group->lock);
9397         }
9398         spin_unlock(&sinfo->lock);
9399
9400         return free_bytes;
9401 }
9402
9403 void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
9404 {
9405         struct btrfs_space_info *sinfo = cache->space_info;
9406         u64 num_bytes;
9407
9408         BUG_ON(!cache->ro);
9409
9410         spin_lock(&sinfo->lock);
9411         spin_lock(&cache->lock);
9412         if (!--cache->ro) {
9413                 num_bytes = cache->key.offset - cache->reserved -
9414                             cache->pinned - cache->bytes_super -
9415                             btrfs_block_group_used(&cache->item);
9416                 sinfo->bytes_readonly -= num_bytes;
9417                 list_del_init(&cache->ro_list);
9418         }
9419         spin_unlock(&cache->lock);
9420         spin_unlock(&sinfo->lock);
9421 }
9422
9423 /*
9424  * checks to see if its even possible to relocate this block group.
9425  *
9426  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9427  * ok to go ahead and try.
9428  */
9429 int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
9430 {
9431         struct btrfs_root *root = fs_info->extent_root;
9432         struct btrfs_block_group_cache *block_group;
9433         struct btrfs_space_info *space_info;
9434         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
9435         struct btrfs_device *device;
9436         struct btrfs_trans_handle *trans;
9437         u64 min_free;
9438         u64 dev_min = 1;
9439         u64 dev_nr = 0;
9440         u64 target;
9441         int debug;
9442         int index;
9443         int full = 0;
9444         int ret = 0;
9445
9446         debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG);
9447
9448         block_group = btrfs_lookup_block_group(fs_info, bytenr);
9449
9450         /* odd, couldn't find the block group, leave it alone */
9451         if (!block_group) {
9452                 if (debug)
9453                         btrfs_warn(fs_info,
9454                                    "can't find block group for bytenr %llu",
9455                                    bytenr);
9456                 return -1;
9457         }
9458
9459         min_free = btrfs_block_group_used(&block_group->item);
9460
9461         /* no bytes used, we're good */
9462         if (!min_free)
9463                 goto out;
9464
9465         space_info = block_group->space_info;
9466         spin_lock(&space_info->lock);
9467
9468         full = space_info->full;
9469
9470         /*
9471          * if this is the last block group we have in this space, we can't
9472          * relocate it unless we're able to allocate a new chunk below.
9473          *
9474          * Otherwise, we need to make sure we have room in the space to handle
9475          * all of the extents from this block group.  If we can, we're good
9476          */
9477         if ((space_info->total_bytes != block_group->key.offset) &&
9478             (btrfs_space_info_used(space_info, false) + min_free <
9479              space_info->total_bytes)) {
9480                 spin_unlock(&space_info->lock);
9481                 goto out;
9482         }
9483         spin_unlock(&space_info->lock);
9484
9485         /*
9486          * ok we don't have enough space, but maybe we have free space on our
9487          * devices to allocate new chunks for relocation, so loop through our
9488          * alloc devices and guess if we have enough space.  if this block
9489          * group is going to be restriped, run checks against the target
9490          * profile instead of the current one.
9491          */
9492         ret = -1;
9493
9494         /*
9495          * index:
9496          *      0: raid10
9497          *      1: raid1
9498          *      2: dup
9499          *      3: raid0
9500          *      4: single
9501          */
9502         target = get_restripe_target(fs_info, block_group->flags);
9503         if (target) {
9504                 index = btrfs_bg_flags_to_raid_index(extended_to_chunk(target));
9505         } else {
9506                 /*
9507                  * this is just a balance, so if we were marked as full
9508                  * we know there is no space for a new chunk
9509                  */
9510                 if (full) {
9511                         if (debug)
9512                                 btrfs_warn(fs_info,
9513                                            "no space to alloc new chunk for block group %llu",
9514                                            block_group->key.objectid);
9515                         goto out;
9516                 }
9517
9518                 index = btrfs_bg_flags_to_raid_index(block_group->flags);
9519         }
9520
9521         if (index == BTRFS_RAID_RAID10) {
9522                 dev_min = 4;
9523                 /* Divide by 2 */
9524                 min_free >>= 1;
9525         } else if (index == BTRFS_RAID_RAID1) {
9526                 dev_min = 2;
9527         } else if (index == BTRFS_RAID_DUP) {
9528                 /* Multiply by 2 */
9529                 min_free <<= 1;
9530         } else if (index == BTRFS_RAID_RAID0) {
9531                 dev_min = fs_devices->rw_devices;
9532                 min_free = div64_u64(min_free, dev_min);
9533         }
9534
9535         /* We need to do this so that we can look at pending chunks */
9536         trans = btrfs_join_transaction(root);
9537         if (IS_ERR(trans)) {
9538                 ret = PTR_ERR(trans);
9539                 goto out;
9540         }
9541
9542         mutex_lock(&fs_info->chunk_mutex);
9543         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9544                 u64 dev_offset;
9545
9546                 /*
9547                  * check to make sure we can actually find a chunk with enough
9548                  * space to fit our block group in.
9549                  */
9550                 if (device->total_bytes > device->bytes_used + min_free &&
9551                     !test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
9552                         ret = find_free_dev_extent(trans, device, min_free,
9553                                                    &dev_offset, NULL);
9554                         if (!ret)
9555                                 dev_nr++;
9556
9557                         if (dev_nr >= dev_min)
9558                                 break;
9559
9560                         ret = -1;
9561                 }
9562         }
9563         if (debug && ret == -1)
9564                 btrfs_warn(fs_info,
9565                            "no space to allocate a new chunk for block group %llu",
9566                            block_group->key.objectid);
9567         mutex_unlock(&fs_info->chunk_mutex);
9568         btrfs_end_transaction(trans);
9569 out:
9570         btrfs_put_block_group(block_group);
9571         return ret;
9572 }
9573
9574 static int find_first_block_group(struct btrfs_fs_info *fs_info,
9575                                   struct btrfs_path *path,
9576                                   struct btrfs_key *key)
9577 {
9578         struct btrfs_root *root = fs_info->extent_root;
9579         int ret = 0;
9580         struct btrfs_key found_key;
9581         struct extent_buffer *leaf;
9582         struct btrfs_block_group_item bg;
9583         u64 flags;
9584         int slot;
9585
9586         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9587         if (ret < 0)
9588                 goto out;
9589
9590         while (1) {
9591                 slot = path->slots[0];
9592                 leaf = path->nodes[0];
9593                 if (slot >= btrfs_header_nritems(leaf)) {
9594                         ret = btrfs_next_leaf(root, path);
9595                         if (ret == 0)
9596                                 continue;
9597                         if (ret < 0)
9598                                 goto out;
9599                         break;
9600                 }
9601                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9602
9603                 if (found_key.objectid >= key->objectid &&
9604                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9605                         struct extent_map_tree *em_tree;
9606                         struct extent_map *em;
9607
9608                         em_tree = &root->fs_info->mapping_tree.map_tree;
9609                         read_lock(&em_tree->lock);
9610                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9611                                                    found_key.offset);
9612                         read_unlock(&em_tree->lock);
9613                         if (!em) {
9614                                 btrfs_err(fs_info,
9615                         "logical %llu len %llu found bg but no related chunk",
9616                                           found_key.objectid, found_key.offset);
9617                                 ret = -ENOENT;
9618                         } else if (em->start != found_key.objectid ||
9619                                    em->len != found_key.offset) {
9620                                 btrfs_err(fs_info,
9621                 "block group %llu len %llu mismatch with chunk %llu len %llu",
9622                                           found_key.objectid, found_key.offset,
9623                                           em->start, em->len);
9624                                 ret = -EUCLEAN;
9625                         } else {
9626                                 read_extent_buffer(leaf, &bg,
9627                                         btrfs_item_ptr_offset(leaf, slot),
9628                                         sizeof(bg));
9629                                 flags = btrfs_block_group_flags(&bg) &
9630                                         BTRFS_BLOCK_GROUP_TYPE_MASK;
9631
9632                                 if (flags != (em->map_lookup->type &
9633                                               BTRFS_BLOCK_GROUP_TYPE_MASK)) {
9634                                         btrfs_err(fs_info,
9635 "block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
9636                                                 found_key.objectid,
9637                                                 found_key.offset, flags,
9638                                                 (BTRFS_BLOCK_GROUP_TYPE_MASK &
9639                                                  em->map_lookup->type));
9640                                         ret = -EUCLEAN;
9641                                 } else {
9642                                         ret = 0;
9643                                 }
9644                         }
9645                         free_extent_map(em);
9646                         goto out;
9647                 }
9648                 path->slots[0]++;
9649         }
9650 out:
9651         return ret;
9652 }
9653
9654 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9655 {
9656         struct btrfs_block_group_cache *block_group;
9657         u64 last = 0;
9658
9659         while (1) {
9660                 struct inode *inode;
9661
9662                 block_group = btrfs_lookup_first_block_group(info, last);
9663                 while (block_group) {
9664                         wait_block_group_cache_done(block_group);
9665                         spin_lock(&block_group->lock);
9666                         if (block_group->iref)
9667                                 break;
9668                         spin_unlock(&block_group->lock);
9669                         block_group = next_block_group(info, block_group);
9670                 }
9671                 if (!block_group) {
9672                         if (last == 0)
9673                                 break;
9674                         last = 0;
9675                         continue;
9676                 }
9677
9678                 inode = block_group->inode;
9679                 block_group->iref = 0;
9680                 block_group->inode = NULL;
9681                 spin_unlock(&block_group->lock);
9682                 ASSERT(block_group->io_ctl.inode == NULL);
9683                 iput(inode);
9684                 last = block_group->key.objectid + block_group->key.offset;
9685                 btrfs_put_block_group(block_group);
9686         }
9687 }
9688
9689 /*
9690  * Must be called only after stopping all workers, since we could have block
9691  * group caching kthreads running, and therefore they could race with us if we
9692  * freed the block groups before stopping them.
9693  */
9694 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9695 {
9696         struct btrfs_block_group_cache *block_group;
9697         struct btrfs_space_info *space_info;
9698         struct btrfs_caching_control *caching_ctl;
9699         struct rb_node *n;
9700
9701         down_write(&info->commit_root_sem);
9702         while (!list_empty(&info->caching_block_groups)) {
9703                 caching_ctl = list_entry(info->caching_block_groups.next,
9704                                          struct btrfs_caching_control, list);
9705                 list_del(&caching_ctl->list);
9706                 put_caching_control(caching_ctl);
9707         }
9708         up_write(&info->commit_root_sem);
9709
9710         spin_lock(&info->unused_bgs_lock);
9711         while (!list_empty(&info->unused_bgs)) {
9712                 block_group = list_first_entry(&info->unused_bgs,
9713                                                struct btrfs_block_group_cache,
9714                                                bg_list);
9715                 list_del_init(&block_group->bg_list);
9716                 btrfs_put_block_group(block_group);
9717         }
9718         spin_unlock(&info->unused_bgs_lock);
9719
9720         spin_lock(&info->block_group_cache_lock);
9721         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9722                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9723                                        cache_node);
9724                 rb_erase(&block_group->cache_node,
9725                          &info->block_group_cache_tree);
9726                 RB_CLEAR_NODE(&block_group->cache_node);
9727                 spin_unlock(&info->block_group_cache_lock);
9728
9729                 down_write(&block_group->space_info->groups_sem);
9730                 list_del(&block_group->list);
9731                 up_write(&block_group->space_info->groups_sem);
9732
9733                 /*
9734                  * We haven't cached this block group, which means we could
9735                  * possibly have excluded extents on this block group.
9736                  */
9737                 if (block_group->cached == BTRFS_CACHE_NO ||
9738                     block_group->cached == BTRFS_CACHE_ERROR)
9739                         free_excluded_extents(block_group);
9740
9741                 btrfs_remove_free_space_cache(block_group);
9742                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
9743                 ASSERT(list_empty(&block_group->dirty_list));
9744                 ASSERT(list_empty(&block_group->io_list));
9745                 ASSERT(list_empty(&block_group->bg_list));
9746                 ASSERT(atomic_read(&block_group->count) == 1);
9747                 btrfs_put_block_group(block_group);
9748
9749                 spin_lock(&info->block_group_cache_lock);
9750         }
9751         spin_unlock(&info->block_group_cache_lock);
9752
9753         /* now that all the block groups are freed, go through and
9754          * free all the space_info structs.  This is only called during
9755          * the final stages of unmount, and so we know nobody is
9756          * using them.  We call synchronize_rcu() once before we start,
9757          * just to be on the safe side.
9758          */
9759         synchronize_rcu();
9760
9761         release_global_block_rsv(info);
9762
9763         while (!list_empty(&info->space_info)) {
9764                 int i;
9765
9766                 space_info = list_entry(info->space_info.next,
9767                                         struct btrfs_space_info,
9768                                         list);
9769
9770                 /*
9771                  * Do not hide this behind enospc_debug, this is actually
9772                  * important and indicates a real bug if this happens.
9773                  */
9774                 if (WARN_ON(space_info->bytes_pinned > 0 ||
9775                             space_info->bytes_reserved > 0 ||
9776                             space_info->bytes_may_use > 0))
9777                         dump_space_info(info, space_info, 0, 0);
9778                 list_del(&space_info->list);
9779                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9780                         struct kobject *kobj;
9781                         kobj = space_info->block_group_kobjs[i];
9782                         space_info->block_group_kobjs[i] = NULL;
9783                         if (kobj) {
9784                                 kobject_del(kobj);
9785                                 kobject_put(kobj);
9786                         }
9787                 }
9788                 kobject_del(&space_info->kobj);
9789                 kobject_put(&space_info->kobj);
9790         }
9791         return 0;
9792 }
9793
9794 /* link_block_group will queue up kobjects to add when we're reclaim-safe */
9795 void btrfs_add_raid_kobjects(struct btrfs_fs_info *fs_info)
9796 {
9797         struct btrfs_space_info *space_info;
9798         struct raid_kobject *rkobj;
9799         LIST_HEAD(list);
9800         int index;
9801         int ret = 0;
9802
9803         spin_lock(&fs_info->pending_raid_kobjs_lock);
9804         list_splice_init(&fs_info->pending_raid_kobjs, &list);
9805         spin_unlock(&fs_info->pending_raid_kobjs_lock);
9806
9807         list_for_each_entry(rkobj, &list, list) {
9808                 space_info = __find_space_info(fs_info, rkobj->flags);
9809                 index = btrfs_bg_flags_to_raid_index(rkobj->flags);
9810
9811                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9812                                   "%s", get_raid_name(index));
9813                 if (ret) {
9814                         kobject_put(&rkobj->kobj);
9815                         break;
9816                 }
9817         }
9818         if (ret)
9819                 btrfs_warn(fs_info,
9820                            "failed to add kobject for block cache, ignoring");
9821 }
9822
9823 static void link_block_group(struct btrfs_block_group_cache *cache)
9824 {
9825         struct btrfs_space_info *space_info = cache->space_info;
9826         struct btrfs_fs_info *fs_info = cache->fs_info;
9827         int index = btrfs_bg_flags_to_raid_index(cache->flags);
9828         bool first = false;
9829
9830         down_write(&space_info->groups_sem);
9831         if (list_empty(&space_info->block_groups[index]))
9832                 first = true;
9833         list_add_tail(&cache->list, &space_info->block_groups[index]);
9834         up_write(&space_info->groups_sem);
9835
9836         if (first) {
9837                 struct raid_kobject *rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9838                 if (!rkobj) {
9839                         btrfs_warn(cache->fs_info,
9840                                 "couldn't alloc memory for raid level kobject");
9841                         return;
9842                 }
9843                 rkobj->flags = cache->flags;
9844                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9845
9846                 spin_lock(&fs_info->pending_raid_kobjs_lock);
9847                 list_add_tail(&rkobj->list, &fs_info->pending_raid_kobjs);
9848                 spin_unlock(&fs_info->pending_raid_kobjs_lock);
9849                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9850         }
9851 }
9852
9853 static struct btrfs_block_group_cache *
9854 btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
9855                                u64 start, u64 size)
9856 {
9857         struct btrfs_block_group_cache *cache;
9858
9859         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9860         if (!cache)
9861                 return NULL;
9862
9863         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9864                                         GFP_NOFS);
9865         if (!cache->free_space_ctl) {
9866                 kfree(cache);
9867                 return NULL;
9868         }
9869
9870         cache->key.objectid = start;
9871         cache->key.offset = size;
9872         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9873
9874         cache->fs_info = fs_info;
9875         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
9876         set_free_space_tree_thresholds(cache);
9877
9878         atomic_set(&cache->count, 1);
9879         spin_lock_init(&cache->lock);
9880         init_rwsem(&cache->data_rwsem);
9881         INIT_LIST_HEAD(&cache->list);
9882         INIT_LIST_HEAD(&cache->cluster_list);
9883         INIT_LIST_HEAD(&cache->bg_list);
9884         INIT_LIST_HEAD(&cache->ro_list);
9885         INIT_LIST_HEAD(&cache->dirty_list);
9886         INIT_LIST_HEAD(&cache->io_list);
9887         btrfs_init_free_space_ctl(cache);
9888         atomic_set(&cache->trimming, 0);
9889         mutex_init(&cache->free_space_lock);
9890         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
9891
9892         return cache;
9893 }
9894
9895
9896 /*
9897  * Iterate all chunks and verify that each of them has the corresponding block
9898  * group
9899  */
9900 static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
9901 {
9902         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
9903         struct extent_map *em;
9904         struct btrfs_block_group_cache *bg;
9905         u64 start = 0;
9906         int ret = 0;
9907
9908         while (1) {
9909                 read_lock(&map_tree->map_tree.lock);
9910                 /*
9911                  * lookup_extent_mapping will return the first extent map
9912                  * intersecting the range, so setting @len to 1 is enough to
9913                  * get the first chunk.
9914                  */
9915                 em = lookup_extent_mapping(&map_tree->map_tree, start, 1);
9916                 read_unlock(&map_tree->map_tree.lock);
9917                 if (!em)
9918                         break;
9919
9920                 bg = btrfs_lookup_block_group(fs_info, em->start);
9921                 if (!bg) {
9922                         btrfs_err(fs_info,
9923         "chunk start=%llu len=%llu doesn't have corresponding block group",
9924                                      em->start, em->len);
9925                         ret = -EUCLEAN;
9926                         free_extent_map(em);
9927                         break;
9928                 }
9929                 if (bg->key.objectid != em->start ||
9930                     bg->key.offset != em->len ||
9931                     (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
9932                     (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
9933                         btrfs_err(fs_info,
9934 "chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
9935                                 em->start, em->len,
9936                                 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
9937                                 bg->key.objectid, bg->key.offset,
9938                                 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
9939                         ret = -EUCLEAN;
9940                         free_extent_map(em);
9941                         btrfs_put_block_group(bg);
9942                         break;
9943                 }
9944                 start = em->start + em->len;
9945                 free_extent_map(em);
9946                 btrfs_put_block_group(bg);
9947         }
9948         return ret;
9949 }
9950
9951 int btrfs_read_block_groups(struct btrfs_fs_info *info)
9952 {
9953         struct btrfs_path *path;
9954         int ret;
9955         struct btrfs_block_group_cache *cache;
9956         struct btrfs_space_info *space_info;
9957         struct btrfs_key key;
9958         struct btrfs_key found_key;
9959         struct extent_buffer *leaf;
9960         int need_clear = 0;
9961         u64 cache_gen;
9962         u64 feature;
9963         int mixed;
9964
9965         feature = btrfs_super_incompat_flags(info->super_copy);
9966         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
9967
9968         key.objectid = 0;
9969         key.offset = 0;
9970         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9971         path = btrfs_alloc_path();
9972         if (!path)
9973                 return -ENOMEM;
9974         path->reada = READA_FORWARD;
9975
9976         cache_gen = btrfs_super_cache_generation(info->super_copy);
9977         if (btrfs_test_opt(info, SPACE_CACHE) &&
9978             btrfs_super_generation(info->super_copy) != cache_gen)
9979                 need_clear = 1;
9980         if (btrfs_test_opt(info, CLEAR_CACHE))
9981                 need_clear = 1;
9982
9983         while (1) {
9984                 ret = find_first_block_group(info, path, &key);
9985                 if (ret > 0)
9986                         break;
9987                 if (ret != 0)
9988                         goto error;
9989
9990                 leaf = path->nodes[0];
9991                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9992
9993                 cache = btrfs_create_block_group_cache(info, found_key.objectid,
9994                                                        found_key.offset);
9995                 if (!cache) {
9996                         ret = -ENOMEM;
9997                         goto error;
9998                 }
9999
10000                 if (need_clear) {
10001                         /*
10002                          * When we mount with old space cache, we need to
10003                          * set BTRFS_DC_CLEAR and set dirty flag.
10004                          *
10005                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10006                          *    truncate the old free space cache inode and
10007                          *    setup a new one.
10008                          * b) Setting 'dirty flag' makes sure that we flush
10009                          *    the new space cache info onto disk.
10010                          */
10011                         if (btrfs_test_opt(info, SPACE_CACHE))
10012                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
10013                 }
10014
10015                 read_extent_buffer(leaf, &cache->item,
10016                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
10017                                    sizeof(cache->item));
10018                 cache->flags = btrfs_block_group_flags(&cache->item);
10019                 if (!mixed &&
10020                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10021                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10022                         btrfs_err(info,
10023 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10024                                   cache->key.objectid);
10025                         ret = -EINVAL;
10026                         goto error;
10027                 }
10028
10029                 key.objectid = found_key.objectid + found_key.offset;
10030                 btrfs_release_path(path);
10031
10032                 /*
10033                  * We need to exclude the super stripes now so that the space
10034                  * info has super bytes accounted for, otherwise we'll think
10035                  * we have more space than we actually do.
10036                  */
10037                 ret = exclude_super_stripes(cache);
10038                 if (ret) {
10039                         /*
10040                          * We may have excluded something, so call this just in
10041                          * case.
10042                          */
10043                         free_excluded_extents(cache);
10044                         btrfs_put_block_group(cache);
10045                         goto error;
10046                 }
10047
10048                 /*
10049                  * check for two cases, either we are full, and therefore
10050                  * don't need to bother with the caching work since we won't
10051                  * find any space, or we are empty, and we can just add all
10052                  * the space in and be done with it.  This saves us _alot_ of
10053                  * time, particularly in the full case.
10054                  */
10055                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10056                         cache->last_byte_to_unpin = (u64)-1;
10057                         cache->cached = BTRFS_CACHE_FINISHED;
10058                         free_excluded_extents(cache);
10059                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10060                         cache->last_byte_to_unpin = (u64)-1;
10061                         cache->cached = BTRFS_CACHE_FINISHED;
10062                         add_new_free_space(cache, found_key.objectid,
10063                                            found_key.objectid +
10064                                            found_key.offset);
10065                         free_excluded_extents(cache);
10066                 }
10067
10068                 ret = btrfs_add_block_group_cache(info, cache);
10069                 if (ret) {
10070                         btrfs_remove_free_space_cache(cache);
10071                         btrfs_put_block_group(cache);
10072                         goto error;
10073                 }
10074
10075                 trace_btrfs_add_block_group(info, cache, 0);
10076                 update_space_info(info, cache->flags, found_key.offset,
10077                                   btrfs_block_group_used(&cache->item),
10078                                   cache->bytes_super, &space_info);
10079
10080                 cache->space_info = space_info;
10081
10082                 link_block_group(cache);
10083
10084                 set_avail_alloc_bits(info, cache->flags);
10085                 if (btrfs_chunk_readonly(info, cache->key.objectid)) {
10086                         inc_block_group_ro(cache, 1);
10087                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10088                         ASSERT(list_empty(&cache->bg_list));
10089                         btrfs_mark_bg_unused(cache);
10090                 }
10091         }
10092
10093         list_for_each_entry_rcu(space_info, &info->space_info, list) {
10094                 if (!(get_alloc_profile(info, space_info->flags) &
10095                       (BTRFS_BLOCK_GROUP_RAID10 |
10096                        BTRFS_BLOCK_GROUP_RAID1 |
10097                        BTRFS_BLOCK_GROUP_RAID5 |
10098                        BTRFS_BLOCK_GROUP_RAID6 |
10099                        BTRFS_BLOCK_GROUP_DUP)))
10100                         continue;
10101                 /*
10102                  * avoid allocating from un-mirrored block group if there are
10103                  * mirrored block groups.
10104                  */
10105                 list_for_each_entry(cache,
10106                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10107                                 list)
10108                         inc_block_group_ro(cache, 1);
10109                 list_for_each_entry(cache,
10110                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10111                                 list)
10112                         inc_block_group_ro(cache, 1);
10113         }
10114
10115         btrfs_add_raid_kobjects(info);
10116         init_global_block_rsv(info);
10117         ret = check_chunk_block_group_mappings(info);
10118 error:
10119         btrfs_free_path(path);
10120         return ret;
10121 }
10122
10123 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
10124 {
10125         struct btrfs_fs_info *fs_info = trans->fs_info;
10126         struct btrfs_block_group_cache *block_group;
10127         struct btrfs_root *extent_root = fs_info->extent_root;
10128         struct btrfs_block_group_item item;
10129         struct btrfs_key key;
10130         int ret = 0;
10131
10132         if (!trans->can_flush_pending_bgs)
10133                 return;
10134
10135         while (!list_empty(&trans->new_bgs)) {
10136                 block_group = list_first_entry(&trans->new_bgs,
10137                                                struct btrfs_block_group_cache,
10138                                                bg_list);
10139                 if (ret)
10140                         goto next;
10141
10142                 spin_lock(&block_group->lock);
10143                 memcpy(&item, &block_group->item, sizeof(item));
10144                 memcpy(&key, &block_group->key, sizeof(key));
10145                 spin_unlock(&block_group->lock);
10146
10147                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10148                                         sizeof(item));
10149                 if (ret)
10150                         btrfs_abort_transaction(trans, ret);
10151                 ret = btrfs_finish_chunk_alloc(trans, key.objectid, key.offset);
10152                 if (ret)
10153                         btrfs_abort_transaction(trans, ret);
10154                 add_block_group_free_space(trans, block_group);
10155                 /* already aborted the transaction if it failed. */
10156 next:
10157                 list_del_init(&block_group->bg_list);
10158         }
10159         btrfs_trans_release_chunk_metadata(trans);
10160 }
10161
10162 int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
10163                            u64 type, u64 chunk_offset, u64 size)
10164 {
10165         struct btrfs_fs_info *fs_info = trans->fs_info;
10166         struct btrfs_block_group_cache *cache;
10167         int ret;
10168
10169         btrfs_set_log_full_commit(fs_info, trans);
10170
10171         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
10172         if (!cache)
10173                 return -ENOMEM;
10174
10175         btrfs_set_block_group_used(&cache->item, bytes_used);
10176         btrfs_set_block_group_chunk_objectid(&cache->item,
10177                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID);
10178         btrfs_set_block_group_flags(&cache->item, type);
10179
10180         cache->flags = type;
10181         cache->last_byte_to_unpin = (u64)-1;
10182         cache->cached = BTRFS_CACHE_FINISHED;
10183         cache->needs_free_space = 1;
10184         ret = exclude_super_stripes(cache);
10185         if (ret) {
10186                 /*
10187                  * We may have excluded something, so call this just in
10188                  * case.
10189                  */
10190                 free_excluded_extents(cache);
10191                 btrfs_put_block_group(cache);
10192                 return ret;
10193         }
10194
10195         add_new_free_space(cache, chunk_offset, chunk_offset + size);
10196
10197         free_excluded_extents(cache);
10198
10199 #ifdef CONFIG_BTRFS_DEBUG
10200         if (btrfs_should_fragment_free_space(cache)) {
10201                 u64 new_bytes_used = size - bytes_used;
10202
10203                 bytes_used += new_bytes_used >> 1;
10204                 fragment_free_space(cache);
10205         }
10206 #endif
10207         /*
10208          * Ensure the corresponding space_info object is created and
10209          * assigned to our block group. We want our bg to be added to the rbtree
10210          * with its ->space_info set.
10211          */
10212         cache->space_info = __find_space_info(fs_info, cache->flags);
10213         ASSERT(cache->space_info);
10214
10215         ret = btrfs_add_block_group_cache(fs_info, cache);
10216         if (ret) {
10217                 btrfs_remove_free_space_cache(cache);
10218                 btrfs_put_block_group(cache);
10219                 return ret;
10220         }
10221
10222         /*
10223          * Now that our block group has its ->space_info set and is inserted in
10224          * the rbtree, update the space info's counters.
10225          */
10226         trace_btrfs_add_block_group(fs_info, cache, 1);
10227         update_space_info(fs_info, cache->flags, size, bytes_used,
10228                                 cache->bytes_super, &cache->space_info);
10229         update_global_block_rsv(fs_info);
10230
10231         link_block_group(cache);
10232
10233         list_add_tail(&cache->bg_list, &trans->new_bgs);
10234
10235         set_avail_alloc_bits(fs_info, type);
10236         return 0;
10237 }
10238
10239 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10240 {
10241         u64 extra_flags = chunk_to_extended(flags) &
10242                                 BTRFS_EXTENDED_PROFILE_MASK;
10243
10244         write_seqlock(&fs_info->profiles_lock);
10245         if (flags & BTRFS_BLOCK_GROUP_DATA)
10246                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10247         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10248                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10249         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10250                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10251         write_sequnlock(&fs_info->profiles_lock);
10252 }
10253
10254 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10255                              u64 group_start, struct extent_map *em)
10256 {
10257         struct btrfs_fs_info *fs_info = trans->fs_info;
10258         struct btrfs_root *root = fs_info->extent_root;
10259         struct btrfs_path *path;
10260         struct btrfs_block_group_cache *block_group;
10261         struct btrfs_free_cluster *cluster;
10262         struct btrfs_root *tree_root = fs_info->tree_root;
10263         struct btrfs_key key;
10264         struct inode *inode;
10265         struct kobject *kobj = NULL;
10266         int ret;
10267         int index;
10268         int factor;
10269         struct btrfs_caching_control *caching_ctl = NULL;
10270         bool remove_em;
10271
10272         block_group = btrfs_lookup_block_group(fs_info, group_start);
10273         BUG_ON(!block_group);
10274         BUG_ON(!block_group->ro);
10275
10276         trace_btrfs_remove_block_group(block_group);
10277         /*
10278          * Free the reserved super bytes from this block group before
10279          * remove it.
10280          */
10281         free_excluded_extents(block_group);
10282         btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
10283                                   block_group->key.offset);
10284
10285         memcpy(&key, &block_group->key, sizeof(key));
10286         index = btrfs_bg_flags_to_raid_index(block_group->flags);
10287         factor = btrfs_bg_type_to_factor(block_group->flags);
10288
10289         /* make sure this block group isn't part of an allocation cluster */
10290         cluster = &fs_info->data_alloc_cluster;
10291         spin_lock(&cluster->refill_lock);
10292         btrfs_return_cluster_to_free_space(block_group, cluster);
10293         spin_unlock(&cluster->refill_lock);
10294
10295         /*
10296          * make sure this block group isn't part of a metadata
10297          * allocation cluster
10298          */
10299         cluster = &fs_info->meta_alloc_cluster;
10300         spin_lock(&cluster->refill_lock);
10301         btrfs_return_cluster_to_free_space(block_group, cluster);
10302         spin_unlock(&cluster->refill_lock);
10303
10304         path = btrfs_alloc_path();
10305         if (!path) {
10306                 ret = -ENOMEM;
10307                 goto out;
10308         }
10309
10310         /*
10311          * get the inode first so any iput calls done for the io_list
10312          * aren't the final iput (no unlinks allowed now)
10313          */
10314         inode = lookup_free_space_inode(fs_info, block_group, path);
10315
10316         mutex_lock(&trans->transaction->cache_write_mutex);
10317         /*
10318          * make sure our free spache cache IO is done before remove the
10319          * free space inode
10320          */
10321         spin_lock(&trans->transaction->dirty_bgs_lock);
10322         if (!list_empty(&block_group->io_list)) {
10323                 list_del_init(&block_group->io_list);
10324
10325                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10326
10327                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10328                 btrfs_wait_cache_io(trans, block_group, path);
10329                 btrfs_put_block_group(block_group);
10330                 spin_lock(&trans->transaction->dirty_bgs_lock);
10331         }
10332
10333         if (!list_empty(&block_group->dirty_list)) {
10334                 list_del_init(&block_group->dirty_list);
10335                 btrfs_put_block_group(block_group);
10336         }
10337         spin_unlock(&trans->transaction->dirty_bgs_lock);
10338         mutex_unlock(&trans->transaction->cache_write_mutex);
10339
10340         if (!IS_ERR(inode)) {
10341                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10342                 if (ret) {
10343                         btrfs_add_delayed_iput(inode);
10344                         goto out;
10345                 }
10346                 clear_nlink(inode);
10347                 /* One for the block groups ref */
10348                 spin_lock(&block_group->lock);
10349                 if (block_group->iref) {
10350                         block_group->iref = 0;
10351                         block_group->inode = NULL;
10352                         spin_unlock(&block_group->lock);
10353                         iput(inode);
10354                 } else {
10355                         spin_unlock(&block_group->lock);
10356                 }
10357                 /* One for our lookup ref */
10358                 btrfs_add_delayed_iput(inode);
10359         }
10360
10361         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10362         key.offset = block_group->key.objectid;
10363         key.type = 0;
10364
10365         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10366         if (ret < 0)
10367                 goto out;
10368         if (ret > 0)
10369                 btrfs_release_path(path);
10370         if (ret == 0) {
10371                 ret = btrfs_del_item(trans, tree_root, path);
10372                 if (ret)
10373                         goto out;
10374                 btrfs_release_path(path);
10375         }
10376
10377         spin_lock(&fs_info->block_group_cache_lock);
10378         rb_erase(&block_group->cache_node,
10379                  &fs_info->block_group_cache_tree);
10380         RB_CLEAR_NODE(&block_group->cache_node);
10381
10382         if (fs_info->first_logical_byte == block_group->key.objectid)
10383                 fs_info->first_logical_byte = (u64)-1;
10384         spin_unlock(&fs_info->block_group_cache_lock);
10385
10386         down_write(&block_group->space_info->groups_sem);
10387         /*
10388          * we must use list_del_init so people can check to see if they
10389          * are still on the list after taking the semaphore
10390          */
10391         list_del_init(&block_group->list);
10392         if (list_empty(&block_group->space_info->block_groups[index])) {
10393                 kobj = block_group->space_info->block_group_kobjs[index];
10394                 block_group->space_info->block_group_kobjs[index] = NULL;
10395                 clear_avail_alloc_bits(fs_info, block_group->flags);
10396         }
10397         up_write(&block_group->space_info->groups_sem);
10398         if (kobj) {
10399                 kobject_del(kobj);
10400                 kobject_put(kobj);
10401         }
10402
10403         if (block_group->has_caching_ctl)
10404                 caching_ctl = get_caching_control(block_group);
10405         if (block_group->cached == BTRFS_CACHE_STARTED)
10406                 wait_block_group_cache_done(block_group);
10407         if (block_group->has_caching_ctl) {
10408                 down_write(&fs_info->commit_root_sem);
10409                 if (!caching_ctl) {
10410                         struct btrfs_caching_control *ctl;
10411
10412                         list_for_each_entry(ctl,
10413                                     &fs_info->caching_block_groups, list)
10414                                 if (ctl->block_group == block_group) {
10415                                         caching_ctl = ctl;
10416                                         refcount_inc(&caching_ctl->count);
10417                                         break;
10418                                 }
10419                 }
10420                 if (caching_ctl)
10421                         list_del_init(&caching_ctl->list);
10422                 up_write(&fs_info->commit_root_sem);
10423                 if (caching_ctl) {
10424                         /* Once for the caching bgs list and once for us. */
10425                         put_caching_control(caching_ctl);
10426                         put_caching_control(caching_ctl);
10427                 }
10428         }
10429
10430         spin_lock(&trans->transaction->dirty_bgs_lock);
10431         if (!list_empty(&block_group->dirty_list)) {
10432                 WARN_ON(1);
10433         }
10434         if (!list_empty(&block_group->io_list)) {
10435                 WARN_ON(1);
10436         }
10437         spin_unlock(&trans->transaction->dirty_bgs_lock);
10438         btrfs_remove_free_space_cache(block_group);
10439
10440         spin_lock(&block_group->space_info->lock);
10441         list_del_init(&block_group->ro_list);
10442
10443         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
10444                 WARN_ON(block_group->space_info->total_bytes
10445                         < block_group->key.offset);
10446                 WARN_ON(block_group->space_info->bytes_readonly
10447                         < block_group->key.offset);
10448                 WARN_ON(block_group->space_info->disk_total
10449                         < block_group->key.offset * factor);
10450         }
10451         block_group->space_info->total_bytes -= block_group->key.offset;
10452         block_group->space_info->bytes_readonly -= block_group->key.offset;
10453         block_group->space_info->disk_total -= block_group->key.offset * factor;
10454
10455         spin_unlock(&block_group->space_info->lock);
10456
10457         memcpy(&key, &block_group->key, sizeof(key));
10458
10459         mutex_lock(&fs_info->chunk_mutex);
10460         if (!list_empty(&em->list)) {
10461                 /* We're in the transaction->pending_chunks list. */
10462                 free_extent_map(em);
10463         }
10464         spin_lock(&block_group->lock);
10465         block_group->removed = 1;
10466         /*
10467          * At this point trimming can't start on this block group, because we
10468          * removed the block group from the tree fs_info->block_group_cache_tree
10469          * so no one can't find it anymore and even if someone already got this
10470          * block group before we removed it from the rbtree, they have already
10471          * incremented block_group->trimming - if they didn't, they won't find
10472          * any free space entries because we already removed them all when we
10473          * called btrfs_remove_free_space_cache().
10474          *
10475          * And we must not remove the extent map from the fs_info->mapping_tree
10476          * to prevent the same logical address range and physical device space
10477          * ranges from being reused for a new block group. This is because our
10478          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10479          * completely transactionless, so while it is trimming a range the
10480          * currently running transaction might finish and a new one start,
10481          * allowing for new block groups to be created that can reuse the same
10482          * physical device locations unless we take this special care.
10483          *
10484          * There may also be an implicit trim operation if the file system
10485          * is mounted with -odiscard. The same protections must remain
10486          * in place until the extents have been discarded completely when
10487          * the transaction commit has completed.
10488          */
10489         remove_em = (atomic_read(&block_group->trimming) == 0);
10490         /*
10491          * Make sure a trimmer task always sees the em in the pinned_chunks list
10492          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10493          * before checking block_group->removed).
10494          */
10495         if (!remove_em) {
10496                 /*
10497                  * Our em might be in trans->transaction->pending_chunks which
10498                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10499                  * and so is the fs_info->pinned_chunks list.
10500                  *
10501                  * So at this point we must be holding the chunk_mutex to avoid
10502                  * any races with chunk allocation (more specifically at
10503                  * volumes.c:contains_pending_extent()), to ensure it always
10504                  * sees the em, either in the pending_chunks list or in the
10505                  * pinned_chunks list.
10506                  */
10507                 list_move_tail(&em->list, &fs_info->pinned_chunks);
10508         }
10509         spin_unlock(&block_group->lock);
10510
10511         if (remove_em) {
10512                 struct extent_map_tree *em_tree;
10513
10514                 em_tree = &fs_info->mapping_tree.map_tree;
10515                 write_lock(&em_tree->lock);
10516                 /*
10517                  * The em might be in the pending_chunks list, so make sure the
10518                  * chunk mutex is locked, since remove_extent_mapping() will
10519                  * delete us from that list.
10520                  */
10521                 remove_extent_mapping(em_tree, em);
10522                 write_unlock(&em_tree->lock);
10523                 /* once for the tree */
10524                 free_extent_map(em);
10525         }
10526
10527         mutex_unlock(&fs_info->chunk_mutex);
10528
10529         ret = remove_block_group_free_space(trans, block_group);
10530         if (ret)
10531                 goto out;
10532
10533         btrfs_put_block_group(block_group);
10534         btrfs_put_block_group(block_group);
10535
10536         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10537         if (ret > 0)
10538                 ret = -EIO;
10539         if (ret < 0)
10540                 goto out;
10541
10542         ret = btrfs_del_item(trans, root, path);
10543 out:
10544         btrfs_free_path(path);
10545         return ret;
10546 }
10547
10548 struct btrfs_trans_handle *
10549 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10550                                      const u64 chunk_offset)
10551 {
10552         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10553         struct extent_map *em;
10554         struct map_lookup *map;
10555         unsigned int num_items;
10556
10557         read_lock(&em_tree->lock);
10558         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10559         read_unlock(&em_tree->lock);
10560         ASSERT(em && em->start == chunk_offset);
10561
10562         /*
10563          * We need to reserve 3 + N units from the metadata space info in order
10564          * to remove a block group (done at btrfs_remove_chunk() and at
10565          * btrfs_remove_block_group()), which are used for:
10566          *
10567          * 1 unit for adding the free space inode's orphan (located in the tree
10568          * of tree roots).
10569          * 1 unit for deleting the block group item (located in the extent
10570          * tree).
10571          * 1 unit for deleting the free space item (located in tree of tree
10572          * roots).
10573          * N units for deleting N device extent items corresponding to each
10574          * stripe (located in the device tree).
10575          *
10576          * In order to remove a block group we also need to reserve units in the
10577          * system space info in order to update the chunk tree (update one or
10578          * more device items and remove one chunk item), but this is done at
10579          * btrfs_remove_chunk() through a call to check_system_chunk().
10580          */
10581         map = em->map_lookup;
10582         num_items = 3 + map->num_stripes;
10583         free_extent_map(em);
10584
10585         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10586                                                            num_items, 1);
10587 }
10588
10589 /*
10590  * Process the unused_bgs list and remove any that don't have any allocated
10591  * space inside of them.
10592  */
10593 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10594 {
10595         struct btrfs_block_group_cache *block_group;
10596         struct btrfs_space_info *space_info;
10597         struct btrfs_trans_handle *trans;
10598         int ret = 0;
10599
10600         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10601                 return;
10602
10603         spin_lock(&fs_info->unused_bgs_lock);
10604         while (!list_empty(&fs_info->unused_bgs)) {
10605                 u64 start, end;
10606                 int trimming;
10607
10608                 block_group = list_first_entry(&fs_info->unused_bgs,
10609                                                struct btrfs_block_group_cache,
10610                                                bg_list);
10611                 list_del_init(&block_group->bg_list);
10612
10613                 space_info = block_group->space_info;
10614
10615                 if (ret || btrfs_mixed_space_info(space_info)) {
10616                         btrfs_put_block_group(block_group);
10617                         continue;
10618                 }
10619                 spin_unlock(&fs_info->unused_bgs_lock);
10620
10621                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10622
10623                 /* Don't want to race with allocators so take the groups_sem */
10624                 down_write(&space_info->groups_sem);
10625                 spin_lock(&block_group->lock);
10626                 if (block_group->reserved || block_group->pinned ||
10627                     btrfs_block_group_used(&block_group->item) ||
10628                     block_group->ro ||
10629                     list_is_singular(&block_group->list)) {
10630                         /*
10631                          * We want to bail if we made new allocations or have
10632                          * outstanding allocations in this block group.  We do
10633                          * the ro check in case balance is currently acting on
10634                          * this block group.
10635                          */
10636                         trace_btrfs_skip_unused_block_group(block_group);
10637                         spin_unlock(&block_group->lock);
10638                         up_write(&space_info->groups_sem);
10639                         goto next;
10640                 }
10641                 spin_unlock(&block_group->lock);
10642
10643                 /* We don't want to force the issue, only flip if it's ok. */
10644                 ret = inc_block_group_ro(block_group, 0);
10645                 up_write(&space_info->groups_sem);
10646                 if (ret < 0) {
10647                         ret = 0;
10648                         goto next;
10649                 }
10650
10651                 /*
10652                  * Want to do this before we do anything else so we can recover
10653                  * properly if we fail to join the transaction.
10654                  */
10655                 trans = btrfs_start_trans_remove_block_group(fs_info,
10656                                                      block_group->key.objectid);
10657                 if (IS_ERR(trans)) {
10658                         btrfs_dec_block_group_ro(block_group);
10659                         ret = PTR_ERR(trans);
10660                         goto next;
10661                 }
10662
10663                 /*
10664                  * We could have pending pinned extents for this block group,
10665                  * just delete them, we don't care about them anymore.
10666                  */
10667                 start = block_group->key.objectid;
10668                 end = start + block_group->key.offset - 1;
10669                 /*
10670                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10671                  * btrfs_finish_extent_commit(). If we are at transaction N,
10672                  * another task might be running finish_extent_commit() for the
10673                  * previous transaction N - 1, and have seen a range belonging
10674                  * to the block group in freed_extents[] before we were able to
10675                  * clear the whole block group range from freed_extents[]. This
10676                  * means that task can lookup for the block group after we
10677                  * unpinned it from freed_extents[] and removed it, leading to
10678                  * a BUG_ON() at btrfs_unpin_extent_range().
10679                  */
10680                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10681                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10682                                   EXTENT_DIRTY);
10683                 if (ret) {
10684                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10685                         btrfs_dec_block_group_ro(block_group);
10686                         goto end_trans;
10687                 }
10688                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10689                                   EXTENT_DIRTY);
10690                 if (ret) {
10691                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10692                         btrfs_dec_block_group_ro(block_group);
10693                         goto end_trans;
10694                 }
10695                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10696
10697                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10698                 spin_lock(&space_info->lock);
10699                 spin_lock(&block_group->lock);
10700
10701                 space_info->bytes_pinned -= block_group->pinned;
10702                 space_info->bytes_readonly += block_group->pinned;
10703                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
10704                                    -block_group->pinned,
10705                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
10706                 block_group->pinned = 0;
10707
10708                 spin_unlock(&block_group->lock);
10709                 spin_unlock(&space_info->lock);
10710
10711                 /* DISCARD can flip during remount */
10712                 trimming = btrfs_test_opt(fs_info, DISCARD);
10713
10714                 /* Implicit trim during transaction commit. */
10715                 if (trimming)
10716                         btrfs_get_block_group_trimming(block_group);
10717
10718                 /*
10719                  * Btrfs_remove_chunk will abort the transaction if things go
10720                  * horribly wrong.
10721                  */
10722                 ret = btrfs_remove_chunk(trans, block_group->key.objectid);
10723
10724                 if (ret) {
10725                         if (trimming)
10726                                 btrfs_put_block_group_trimming(block_group);
10727                         goto end_trans;
10728                 }
10729
10730                 /*
10731                  * If we're not mounted with -odiscard, we can just forget
10732                  * about this block group. Otherwise we'll need to wait
10733                  * until transaction commit to do the actual discard.
10734                  */
10735                 if (trimming) {
10736                         spin_lock(&fs_info->unused_bgs_lock);
10737                         /*
10738                          * A concurrent scrub might have added us to the list
10739                          * fs_info->unused_bgs, so use a list_move operation
10740                          * to add the block group to the deleted_bgs list.
10741                          */
10742                         list_move(&block_group->bg_list,
10743                                   &trans->transaction->deleted_bgs);
10744                         spin_unlock(&fs_info->unused_bgs_lock);
10745                         btrfs_get_block_group(block_group);
10746                 }
10747 end_trans:
10748                 btrfs_end_transaction(trans);
10749 next:
10750                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10751                 btrfs_put_block_group(block_group);
10752                 spin_lock(&fs_info->unused_bgs_lock);
10753         }
10754         spin_unlock(&fs_info->unused_bgs_lock);
10755 }
10756
10757 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10758 {
10759         struct btrfs_super_block *disk_super;
10760         u64 features;
10761         u64 flags;
10762         int mixed = 0;
10763         int ret;
10764
10765         disk_super = fs_info->super_copy;
10766         if (!btrfs_super_root(disk_super))
10767                 return -EINVAL;
10768
10769         features = btrfs_super_incompat_flags(disk_super);
10770         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10771                 mixed = 1;
10772
10773         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10774         ret = create_space_info(fs_info, flags);
10775         if (ret)
10776                 goto out;
10777
10778         if (mixed) {
10779                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10780                 ret = create_space_info(fs_info, flags);
10781         } else {
10782                 flags = BTRFS_BLOCK_GROUP_METADATA;
10783                 ret = create_space_info(fs_info, flags);
10784                 if (ret)
10785                         goto out;
10786
10787                 flags = BTRFS_BLOCK_GROUP_DATA;
10788                 ret = create_space_info(fs_info, flags);
10789         }
10790 out:
10791         return ret;
10792 }
10793
10794 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
10795                                    u64 start, u64 end)
10796 {
10797         return unpin_extent_range(fs_info, start, end, false);
10798 }
10799
10800 /*
10801  * It used to be that old block groups would be left around forever.
10802  * Iterating over them would be enough to trim unused space.  Since we
10803  * now automatically remove them, we also need to iterate over unallocated
10804  * space.
10805  *
10806  * We don't want a transaction for this since the discard may take a
10807  * substantial amount of time.  We don't require that a transaction be
10808  * running, but we do need to take a running transaction into account
10809  * to ensure that we're not discarding chunks that were released or
10810  * allocated in the current transaction.
10811  *
10812  * Holding the chunks lock will prevent other threads from allocating
10813  * or releasing chunks, but it won't prevent a running transaction
10814  * from committing and releasing the memory that the pending chunks
10815  * list head uses.  For that, we need to take a reference to the
10816  * transaction and hold the commit root sem.  We only need to hold
10817  * it while performing the free space search since we have already
10818  * held back allocations.
10819  */
10820 static int btrfs_trim_free_extents(struct btrfs_device *device,
10821                                    u64 minlen, u64 *trimmed)
10822 {
10823         u64 start = 0, len = 0;
10824         int ret;
10825
10826         *trimmed = 0;
10827
10828         /* Discard not supported = nothing to do. */
10829         if (!blk_queue_discard(bdev_get_queue(device->bdev)))
10830                 return 0;
10831
10832         /* Not writeable = nothing to do. */
10833         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
10834                 return 0;
10835
10836         /* No free space = nothing to do. */
10837         if (device->total_bytes <= device->bytes_used)
10838                 return 0;
10839
10840         ret = 0;
10841
10842         while (1) {
10843                 struct btrfs_fs_info *fs_info = device->fs_info;
10844                 struct btrfs_transaction *trans;
10845                 u64 bytes;
10846
10847                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10848                 if (ret)
10849                         break;
10850
10851                 ret = down_read_killable(&fs_info->commit_root_sem);
10852                 if (ret) {
10853                         mutex_unlock(&fs_info->chunk_mutex);
10854                         break;
10855                 }
10856
10857                 spin_lock(&fs_info->trans_lock);
10858                 trans = fs_info->running_transaction;
10859                 if (trans)
10860                         refcount_inc(&trans->use_count);
10861                 spin_unlock(&fs_info->trans_lock);
10862
10863                 if (!trans)
10864                         up_read(&fs_info->commit_root_sem);
10865
10866                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10867                                                  &start, &len);
10868                 if (trans) {
10869                         up_read(&fs_info->commit_root_sem);
10870                         btrfs_put_transaction(trans);
10871                 }
10872
10873                 if (ret) {
10874                         mutex_unlock(&fs_info->chunk_mutex);
10875                         if (ret == -ENOSPC)
10876                                 ret = 0;
10877                         break;
10878                 }
10879
10880                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10881                 mutex_unlock(&fs_info->chunk_mutex);
10882
10883                 if (ret)
10884                         break;
10885
10886                 start += len;
10887                 *trimmed += bytes;
10888
10889                 if (fatal_signal_pending(current)) {
10890                         ret = -ERESTARTSYS;
10891                         break;
10892                 }
10893
10894                 cond_resched();
10895         }
10896
10897         return ret;
10898 }
10899
10900 /*
10901  * Trim the whole filesystem by:
10902  * 1) trimming the free space in each block group
10903  * 2) trimming the unallocated space on each device
10904  *
10905  * This will also continue trimming even if a block group or device encounters
10906  * an error.  The return value will be the last error, or 0 if nothing bad
10907  * happens.
10908  */
10909 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
10910 {
10911         struct btrfs_block_group_cache *cache = NULL;
10912         struct btrfs_device *device;
10913         struct list_head *devices;
10914         u64 group_trimmed;
10915         u64 start;
10916         u64 end;
10917         u64 trimmed = 0;
10918         u64 bg_failed = 0;
10919         u64 dev_failed = 0;
10920         int bg_ret = 0;
10921         int dev_ret = 0;
10922         int ret = 0;
10923
10924         cache = btrfs_lookup_first_block_group(fs_info, range->start);
10925         for (; cache; cache = next_block_group(fs_info, cache)) {
10926                 if (cache->key.objectid >= (range->start + range->len)) {
10927                         btrfs_put_block_group(cache);
10928                         break;
10929                 }
10930
10931                 start = max(range->start, cache->key.objectid);
10932                 end = min(range->start + range->len,
10933                                 cache->key.objectid + cache->key.offset);
10934
10935                 if (end - start >= range->minlen) {
10936                         if (!block_group_cache_done(cache)) {
10937                                 ret = cache_block_group(cache, 0);
10938                                 if (ret) {
10939                                         bg_failed++;
10940                                         bg_ret = ret;
10941                                         continue;
10942                                 }
10943                                 ret = wait_block_group_cache_done(cache);
10944                                 if (ret) {
10945                                         bg_failed++;
10946                                         bg_ret = ret;
10947                                         continue;
10948                                 }
10949                         }
10950                         ret = btrfs_trim_block_group(cache,
10951                                                      &group_trimmed,
10952                                                      start,
10953                                                      end,
10954                                                      range->minlen);
10955
10956                         trimmed += group_trimmed;
10957                         if (ret) {
10958                                 bg_failed++;
10959                                 bg_ret = ret;
10960                                 continue;
10961                         }
10962                 }
10963         }
10964
10965         if (bg_failed)
10966                 btrfs_warn(fs_info,
10967                         "failed to trim %llu block group(s), last error %d",
10968                         bg_failed, bg_ret);
10969         mutex_lock(&fs_info->fs_devices->device_list_mutex);
10970         devices = &fs_info->fs_devices->devices;
10971         list_for_each_entry(device, devices, dev_list) {
10972                 ret = btrfs_trim_free_extents(device, range->minlen,
10973                                               &group_trimmed);
10974                 if (ret) {
10975                         dev_failed++;
10976                         dev_ret = ret;
10977                         break;
10978                 }
10979
10980                 trimmed += group_trimmed;
10981         }
10982         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
10983
10984         if (dev_failed)
10985                 btrfs_warn(fs_info,
10986                         "failed to trim %llu device(s), last error %d",
10987                         dev_failed, dev_ret);
10988         range->len = trimmed;
10989         if (bg_ret)
10990                 return bg_ret;
10991         return dev_ret;
10992 }
10993
10994 /*
10995  * btrfs_{start,end}_write_no_snapshotting() are similar to
10996  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10997  * data into the page cache through nocow before the subvolume is snapshoted,
10998  * but flush the data into disk after the snapshot creation, or to prevent
10999  * operations while snapshotting is ongoing and that cause the snapshot to be
11000  * inconsistent (writes followed by expanding truncates for example).
11001  */
11002 void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
11003 {
11004         percpu_counter_dec(&root->subv_writers->counter);
11005         cond_wake_up(&root->subv_writers->wait);
11006 }
11007
11008 int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
11009 {
11010         if (atomic_read(&root->will_be_snapshotted))
11011                 return 0;
11012
11013         percpu_counter_inc(&root->subv_writers->counter);
11014         /*
11015          * Make sure counter is updated before we check for snapshot creation.
11016          */
11017         smp_mb();
11018         if (atomic_read(&root->will_be_snapshotted)) {
11019                 btrfs_end_write_no_snapshotting(root);
11020                 return 0;
11021         }
11022         return 1;
11023 }
11024
11025 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11026 {
11027         while (true) {
11028                 int ret;
11029
11030                 ret = btrfs_start_write_no_snapshotting(root);
11031                 if (ret)
11032                         break;
11033                 wait_var_event(&root->will_be_snapshotted,
11034                                !atomic_read(&root->will_be_snapshotted));
11035         }
11036 }
11037
11038 void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg)
11039 {
11040         struct btrfs_fs_info *fs_info = bg->fs_info;
11041
11042         spin_lock(&fs_info->unused_bgs_lock);
11043         if (list_empty(&bg->bg_list)) {
11044                 btrfs_get_block_group(bg);
11045                 trace_btrfs_add_unused_block_group(bg);
11046                 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
11047         }
11048         spin_unlock(&fs_info->unused_bgs_lock);
11049 }