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         return ret;
2370 }
2371
2372 static inline struct btrfs_delayed_ref_node *
2373 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2374 {
2375         struct btrfs_delayed_ref_node *ref;
2376
2377         if (RB_EMPTY_ROOT(&head->ref_tree))
2378                 return NULL;
2379
2380         /*
2381          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2382          * This is to prevent a ref count from going down to zero, which deletes
2383          * the extent item from the extent tree, when there still are references
2384          * to add, which would fail because they would not find the extent item.
2385          */
2386         if (!list_empty(&head->ref_add_list))
2387                 return list_first_entry(&head->ref_add_list,
2388                                 struct btrfs_delayed_ref_node, add_list);
2389
2390         ref = rb_entry(rb_first(&head->ref_tree),
2391                        struct btrfs_delayed_ref_node, ref_node);
2392         ASSERT(list_empty(&ref->add_list));
2393         return ref;
2394 }
2395
2396 static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
2397                                       struct btrfs_delayed_ref_head *head)
2398 {
2399         spin_lock(&delayed_refs->lock);
2400         head->processing = 0;
2401         delayed_refs->num_heads_ready++;
2402         spin_unlock(&delayed_refs->lock);
2403         btrfs_delayed_ref_unlock(head);
2404 }
2405
2406 static int cleanup_extent_op(struct btrfs_trans_handle *trans,
2407                              struct btrfs_delayed_ref_head *head)
2408 {
2409         struct btrfs_delayed_extent_op *extent_op = head->extent_op;
2410         int ret;
2411
2412         if (!extent_op)
2413                 return 0;
2414         head->extent_op = NULL;
2415         if (head->must_insert_reserved) {
2416                 btrfs_free_delayed_extent_op(extent_op);
2417                 return 0;
2418         }
2419         spin_unlock(&head->lock);
2420         ret = run_delayed_extent_op(trans, head, extent_op);
2421         btrfs_free_delayed_extent_op(extent_op);
2422         return ret ? ret : 1;
2423 }
2424
2425 static int cleanup_ref_head(struct btrfs_trans_handle *trans,
2426                             struct btrfs_delayed_ref_head *head)
2427 {
2428
2429         struct btrfs_fs_info *fs_info = trans->fs_info;
2430         struct btrfs_delayed_ref_root *delayed_refs;
2431         int ret;
2432
2433         delayed_refs = &trans->transaction->delayed_refs;
2434
2435         ret = cleanup_extent_op(trans, head);
2436         if (ret < 0) {
2437                 unselect_delayed_ref_head(delayed_refs, head);
2438                 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2439                 return ret;
2440         } else if (ret) {
2441                 return ret;
2442         }
2443
2444         /*
2445          * Need to drop our head ref lock and re-acquire the delayed ref lock
2446          * and then re-check to make sure nobody got added.
2447          */
2448         spin_unlock(&head->lock);
2449         spin_lock(&delayed_refs->lock);
2450         spin_lock(&head->lock);
2451         if (!RB_EMPTY_ROOT(&head->ref_tree) || head->extent_op) {
2452                 spin_unlock(&head->lock);
2453                 spin_unlock(&delayed_refs->lock);
2454                 return 1;
2455         }
2456         delayed_refs->num_heads--;
2457         rb_erase(&head->href_node, &delayed_refs->href_root);
2458         RB_CLEAR_NODE(&head->href_node);
2459         spin_unlock(&head->lock);
2460         spin_unlock(&delayed_refs->lock);
2461         atomic_dec(&delayed_refs->num_entries);
2462
2463         trace_run_delayed_ref_head(fs_info, head, 0);
2464
2465         if (head->total_ref_mod < 0) {
2466                 struct btrfs_space_info *space_info;
2467                 u64 flags;
2468
2469                 if (head->is_data)
2470                         flags = BTRFS_BLOCK_GROUP_DATA;
2471                 else if (head->is_system)
2472                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
2473                 else
2474                         flags = BTRFS_BLOCK_GROUP_METADATA;
2475                 space_info = __find_space_info(fs_info, flags);
2476                 ASSERT(space_info);
2477                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
2478                                    -head->num_bytes,
2479                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
2480
2481                 if (head->is_data) {
2482                         spin_lock(&delayed_refs->lock);
2483                         delayed_refs->pending_csums -= head->num_bytes;
2484                         spin_unlock(&delayed_refs->lock);
2485                 }
2486         }
2487
2488         if (head->must_insert_reserved) {
2489                 btrfs_pin_extent(fs_info, head->bytenr,
2490                                  head->num_bytes, 1);
2491                 if (head->is_data) {
2492                         ret = btrfs_del_csums(trans, fs_info, head->bytenr,
2493                                               head->num_bytes);
2494                 }
2495         }
2496
2497         /* Also free its reserved qgroup space */
2498         btrfs_qgroup_free_delayed_ref(fs_info, head->qgroup_ref_root,
2499                                       head->qgroup_reserved);
2500         btrfs_delayed_ref_unlock(head);
2501         btrfs_put_delayed_ref_head(head);
2502         return 0;
2503 }
2504
2505 /*
2506  * Returns 0 on success or if called with an already aborted transaction.
2507  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2508  */
2509 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2510                                              unsigned long nr)
2511 {
2512         struct btrfs_fs_info *fs_info = trans->fs_info;
2513         struct btrfs_delayed_ref_root *delayed_refs;
2514         struct btrfs_delayed_ref_node *ref;
2515         struct btrfs_delayed_ref_head *locked_ref = NULL;
2516         struct btrfs_delayed_extent_op *extent_op;
2517         ktime_t start = ktime_get();
2518         int ret;
2519         unsigned long count = 0;
2520         unsigned long actual_count = 0;
2521         int must_insert_reserved = 0;
2522
2523         delayed_refs = &trans->transaction->delayed_refs;
2524         while (1) {
2525                 if (!locked_ref) {
2526                         if (count >= nr)
2527                                 break;
2528
2529                         spin_lock(&delayed_refs->lock);
2530                         locked_ref = btrfs_select_ref_head(trans);
2531                         if (!locked_ref) {
2532                                 spin_unlock(&delayed_refs->lock);
2533                                 break;
2534                         }
2535
2536                         /* grab the lock that says we are going to process
2537                          * all the refs for this head */
2538                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2539                         spin_unlock(&delayed_refs->lock);
2540                         /*
2541                          * we may have dropped the spin lock to get the head
2542                          * mutex lock, and that might have given someone else
2543                          * time to free the head.  If that's true, it has been
2544                          * removed from our list and we can move on.
2545                          */
2546                         if (ret == -EAGAIN) {
2547                                 locked_ref = NULL;
2548                                 count++;
2549                                 continue;
2550                         }
2551                 }
2552
2553                 /*
2554                  * We need to try and merge add/drops of the same ref since we
2555                  * can run into issues with relocate dropping the implicit ref
2556                  * and then it being added back again before the drop can
2557                  * finish.  If we merged anything we need to re-loop so we can
2558                  * get a good ref.
2559                  * Or we can get node references of the same type that weren't
2560                  * merged when created due to bumps in the tree mod seq, and
2561                  * we need to merge them to prevent adding an inline extent
2562                  * backref before dropping it (triggering a BUG_ON at
2563                  * insert_inline_extent_backref()).
2564                  */
2565                 spin_lock(&locked_ref->lock);
2566                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2567
2568                 ref = select_delayed_ref(locked_ref);
2569
2570                 if (ref && ref->seq &&
2571                     btrfs_check_delayed_seq(fs_info, ref->seq)) {
2572                         spin_unlock(&locked_ref->lock);
2573                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2574                         locked_ref = NULL;
2575                         cond_resched();
2576                         count++;
2577                         continue;
2578                 }
2579
2580                 /*
2581                  * We're done processing refs in this ref_head, clean everything
2582                  * up and move on to the next ref_head.
2583                  */
2584                 if (!ref) {
2585                         ret = cleanup_ref_head(trans, locked_ref);
2586                         if (ret > 0 ) {
2587                                 /* We dropped our lock, we need to loop. */
2588                                 ret = 0;
2589                                 continue;
2590                         } else if (ret) {
2591                                 return ret;
2592                         }
2593                         locked_ref = NULL;
2594                         count++;
2595                         continue;
2596                 }
2597
2598                 actual_count++;
2599                 ref->in_tree = 0;
2600                 rb_erase(&ref->ref_node, &locked_ref->ref_tree);
2601                 RB_CLEAR_NODE(&ref->ref_node);
2602                 if (!list_empty(&ref->add_list))
2603                         list_del(&ref->add_list);
2604                 /*
2605                  * When we play the delayed ref, also correct the ref_mod on
2606                  * head
2607                  */
2608                 switch (ref->action) {
2609                 case BTRFS_ADD_DELAYED_REF:
2610                 case BTRFS_ADD_DELAYED_EXTENT:
2611                         locked_ref->ref_mod -= ref->ref_mod;
2612                         break;
2613                 case BTRFS_DROP_DELAYED_REF:
2614                         locked_ref->ref_mod += ref->ref_mod;
2615                         break;
2616                 default:
2617                         WARN_ON(1);
2618                 }
2619                 atomic_dec(&delayed_refs->num_entries);
2620
2621                 /*
2622                  * Record the must-insert_reserved flag before we drop the spin
2623                  * lock.
2624                  */
2625                 must_insert_reserved = locked_ref->must_insert_reserved;
2626                 locked_ref->must_insert_reserved = 0;
2627
2628                 extent_op = locked_ref->extent_op;
2629                 locked_ref->extent_op = NULL;
2630                 spin_unlock(&locked_ref->lock);
2631
2632                 ret = run_one_delayed_ref(trans, ref, extent_op,
2633                                           must_insert_reserved);
2634
2635                 btrfs_free_delayed_extent_op(extent_op);
2636                 if (ret) {
2637                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2638                         btrfs_put_delayed_ref(ref);
2639                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2640                                     ret);
2641                         return ret;
2642                 }
2643
2644                 btrfs_put_delayed_ref(ref);
2645                 count++;
2646                 cond_resched();
2647         }
2648
2649         /*
2650          * We don't want to include ref heads since we can have empty ref heads
2651          * and those will drastically skew our runtime down since we just do
2652          * accounting, no actual extent tree updates.
2653          */
2654         if (actual_count > 0) {
2655                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2656                 u64 avg;
2657
2658                 /*
2659                  * We weigh the current average higher than our current runtime
2660                  * to avoid large swings in the average.
2661                  */
2662                 spin_lock(&delayed_refs->lock);
2663                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2664                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2665                 spin_unlock(&delayed_refs->lock);
2666         }
2667         return 0;
2668 }
2669
2670 #ifdef SCRAMBLE_DELAYED_REFS
2671 /*
2672  * Normally delayed refs get processed in ascending bytenr order. This
2673  * correlates in most cases to the order added. To expose dependencies on this
2674  * order, we start to process the tree in the middle instead of the beginning
2675  */
2676 static u64 find_middle(struct rb_root *root)
2677 {
2678         struct rb_node *n = root->rb_node;
2679         struct btrfs_delayed_ref_node *entry;
2680         int alt = 1;
2681         u64 middle;
2682         u64 first = 0, last = 0;
2683
2684         n = rb_first(root);
2685         if (n) {
2686                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2687                 first = entry->bytenr;
2688         }
2689         n = rb_last(root);
2690         if (n) {
2691                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2692                 last = entry->bytenr;
2693         }
2694         n = root->rb_node;
2695
2696         while (n) {
2697                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2698                 WARN_ON(!entry->in_tree);
2699
2700                 middle = entry->bytenr;
2701
2702                 if (alt)
2703                         n = n->rb_left;
2704                 else
2705                         n = n->rb_right;
2706
2707                 alt = 1 - alt;
2708         }
2709         return middle;
2710 }
2711 #endif
2712
2713 static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2714 {
2715         u64 num_bytes;
2716
2717         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2718                              sizeof(struct btrfs_extent_inline_ref));
2719         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2720                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2721
2722         /*
2723          * We don't ever fill up leaves all the way so multiply by 2 just to be
2724          * closer to what we're really going to want to use.
2725          */
2726         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2727 }
2728
2729 /*
2730  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2731  * would require to store the csums for that many bytes.
2732  */
2733 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2734 {
2735         u64 csum_size;
2736         u64 num_csums_per_leaf;
2737         u64 num_csums;
2738
2739         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2740         num_csums_per_leaf = div64_u64(csum_size,
2741                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2742         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2743         num_csums += num_csums_per_leaf - 1;
2744         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2745         return num_csums;
2746 }
2747
2748 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2749                                        struct btrfs_fs_info *fs_info)
2750 {
2751         struct btrfs_block_rsv *global_rsv;
2752         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2753         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2754         unsigned int num_dirty_bgs = trans->transaction->num_dirty_bgs;
2755         u64 num_bytes, num_dirty_bgs_bytes;
2756         int ret = 0;
2757
2758         num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
2759         num_heads = heads_to_leaves(fs_info, num_heads);
2760         if (num_heads > 1)
2761                 num_bytes += (num_heads - 1) * fs_info->nodesize;
2762         num_bytes <<= 1;
2763         num_bytes += btrfs_csum_bytes_to_leaves(fs_info, csum_bytes) *
2764                                                         fs_info->nodesize;
2765         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(fs_info,
2766                                                              num_dirty_bgs);
2767         global_rsv = &fs_info->global_block_rsv;
2768
2769         /*
2770          * If we can't allocate any more chunks lets make sure we have _lots_ of
2771          * wiggle room since running delayed refs can create more delayed refs.
2772          */
2773         if (global_rsv->space_info->full) {
2774                 num_dirty_bgs_bytes <<= 1;
2775                 num_bytes <<= 1;
2776         }
2777
2778         spin_lock(&global_rsv->lock);
2779         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2780                 ret = 1;
2781         spin_unlock(&global_rsv->lock);
2782         return ret;
2783 }
2784
2785 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2786                                        struct btrfs_fs_info *fs_info)
2787 {
2788         u64 num_entries =
2789                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2790         u64 avg_runtime;
2791         u64 val;
2792
2793         smp_mb();
2794         avg_runtime = fs_info->avg_delayed_ref_runtime;
2795         val = num_entries * avg_runtime;
2796         if (val >= NSEC_PER_SEC)
2797                 return 1;
2798         if (val >= NSEC_PER_SEC / 2)
2799                 return 2;
2800
2801         return btrfs_check_space_for_delayed_refs(trans, fs_info);
2802 }
2803
2804 struct async_delayed_refs {
2805         struct btrfs_root *root;
2806         u64 transid;
2807         int count;
2808         int error;
2809         int sync;
2810         struct completion wait;
2811         struct btrfs_work work;
2812 };
2813
2814 static inline struct async_delayed_refs *
2815 to_async_delayed_refs(struct btrfs_work *work)
2816 {
2817         return container_of(work, struct async_delayed_refs, work);
2818 }
2819
2820 static void delayed_ref_async_start(struct btrfs_work *work)
2821 {
2822         struct async_delayed_refs *async = to_async_delayed_refs(work);
2823         struct btrfs_trans_handle *trans;
2824         struct btrfs_fs_info *fs_info = async->root->fs_info;
2825         int ret;
2826
2827         /* if the commit is already started, we don't need to wait here */
2828         if (btrfs_transaction_blocked(fs_info))
2829                 goto done;
2830
2831         trans = btrfs_join_transaction(async->root);
2832         if (IS_ERR(trans)) {
2833                 async->error = PTR_ERR(trans);
2834                 goto done;
2835         }
2836
2837         /*
2838          * trans->sync means that when we call end_transaction, we won't
2839          * wait on delayed refs
2840          */
2841         trans->sync = true;
2842
2843         /* Don't bother flushing if we got into a different transaction */
2844         if (trans->transid > async->transid)
2845                 goto end;
2846
2847         ret = btrfs_run_delayed_refs(trans, async->count);
2848         if (ret)
2849                 async->error = ret;
2850 end:
2851         ret = btrfs_end_transaction(trans);
2852         if (ret && !async->error)
2853                 async->error = ret;
2854 done:
2855         if (async->sync)
2856                 complete(&async->wait);
2857         else
2858                 kfree(async);
2859 }
2860
2861 int btrfs_async_run_delayed_refs(struct btrfs_fs_info *fs_info,
2862                                  unsigned long count, u64 transid, int wait)
2863 {
2864         struct async_delayed_refs *async;
2865         int ret;
2866
2867         async = kmalloc(sizeof(*async), GFP_NOFS);
2868         if (!async)
2869                 return -ENOMEM;
2870
2871         async->root = fs_info->tree_root;
2872         async->count = count;
2873         async->error = 0;
2874         async->transid = transid;
2875         if (wait)
2876                 async->sync = 1;
2877         else
2878                 async->sync = 0;
2879         init_completion(&async->wait);
2880
2881         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2882                         delayed_ref_async_start, NULL, NULL);
2883
2884         btrfs_queue_work(fs_info->extent_workers, &async->work);
2885
2886         if (wait) {
2887                 wait_for_completion(&async->wait);
2888                 ret = async->error;
2889                 kfree(async);
2890                 return ret;
2891         }
2892         return 0;
2893 }
2894
2895 /*
2896  * this starts processing the delayed reference count updates and
2897  * extent insertions we have queued up so far.  count can be
2898  * 0, which means to process everything in the tree at the start
2899  * of the run (but not newly added entries), or it can be some target
2900  * number you'd like to process.
2901  *
2902  * Returns 0 on success or if called with an aborted transaction
2903  * Returns <0 on error and aborts the transaction
2904  */
2905 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2906                            unsigned long count)
2907 {
2908         struct btrfs_fs_info *fs_info = trans->fs_info;
2909         struct rb_node *node;
2910         struct btrfs_delayed_ref_root *delayed_refs;
2911         struct btrfs_delayed_ref_head *head;
2912         int ret;
2913         int run_all = count == (unsigned long)-1;
2914         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2915
2916         /* We'll clean this up in btrfs_cleanup_transaction */
2917         if (trans->aborted)
2918                 return 0;
2919
2920         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2921                 return 0;
2922
2923         delayed_refs = &trans->transaction->delayed_refs;
2924         if (count == 0)
2925                 count = atomic_read(&delayed_refs->num_entries) * 2;
2926
2927 again:
2928 #ifdef SCRAMBLE_DELAYED_REFS
2929         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2930 #endif
2931         trans->can_flush_pending_bgs = false;
2932         ret = __btrfs_run_delayed_refs(trans, count);
2933         if (ret < 0) {
2934                 btrfs_abort_transaction(trans, ret);
2935                 return ret;
2936         }
2937
2938         if (run_all) {
2939                 if (!list_empty(&trans->new_bgs))
2940                         btrfs_create_pending_block_groups(trans);
2941
2942                 spin_lock(&delayed_refs->lock);
2943                 node = rb_first(&delayed_refs->href_root);
2944                 if (!node) {
2945                         spin_unlock(&delayed_refs->lock);
2946                         goto out;
2947                 }
2948                 head = rb_entry(node, struct btrfs_delayed_ref_head,
2949                                 href_node);
2950                 refcount_inc(&head->refs);
2951                 spin_unlock(&delayed_refs->lock);
2952
2953                 /* Mutex was contended, block until it's released and retry. */
2954                 mutex_lock(&head->mutex);
2955                 mutex_unlock(&head->mutex);
2956
2957                 btrfs_put_delayed_ref_head(head);
2958                 cond_resched();
2959                 goto again;
2960         }
2961 out:
2962         trans->can_flush_pending_bgs = can_flush_pending_bgs;
2963         return 0;
2964 }
2965
2966 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2967                                 struct btrfs_fs_info *fs_info,
2968                                 u64 bytenr, u64 num_bytes, u64 flags,
2969                                 int level, int is_data)
2970 {
2971         struct btrfs_delayed_extent_op *extent_op;
2972         int ret;
2973
2974         extent_op = btrfs_alloc_delayed_extent_op();
2975         if (!extent_op)
2976                 return -ENOMEM;
2977
2978         extent_op->flags_to_set = flags;
2979         extent_op->update_flags = true;
2980         extent_op->update_key = false;
2981         extent_op->is_data = is_data ? true : false;
2982         extent_op->level = level;
2983
2984         ret = btrfs_add_delayed_extent_op(fs_info, trans, bytenr,
2985                                           num_bytes, extent_op);
2986         if (ret)
2987                 btrfs_free_delayed_extent_op(extent_op);
2988         return ret;
2989 }
2990
2991 static noinline int check_delayed_ref(struct btrfs_root *root,
2992                                       struct btrfs_path *path,
2993                                       u64 objectid, u64 offset, u64 bytenr)
2994 {
2995         struct btrfs_delayed_ref_head *head;
2996         struct btrfs_delayed_ref_node *ref;
2997         struct btrfs_delayed_data_ref *data_ref;
2998         struct btrfs_delayed_ref_root *delayed_refs;
2999         struct btrfs_transaction *cur_trans;
3000         struct rb_node *node;
3001         int ret = 0;
3002
3003         spin_lock(&root->fs_info->trans_lock);
3004         cur_trans = root->fs_info->running_transaction;
3005         if (cur_trans)
3006                 refcount_inc(&cur_trans->use_count);
3007         spin_unlock(&root->fs_info->trans_lock);
3008         if (!cur_trans)
3009                 return 0;
3010
3011         delayed_refs = &cur_trans->delayed_refs;
3012         spin_lock(&delayed_refs->lock);
3013         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3014         if (!head) {
3015                 spin_unlock(&delayed_refs->lock);
3016                 btrfs_put_transaction(cur_trans);
3017                 return 0;
3018         }
3019
3020         if (!mutex_trylock(&head->mutex)) {
3021                 refcount_inc(&head->refs);
3022                 spin_unlock(&delayed_refs->lock);
3023
3024                 btrfs_release_path(path);
3025
3026                 /*
3027                  * Mutex was contended, block until it's released and let
3028                  * caller try again
3029                  */
3030                 mutex_lock(&head->mutex);
3031                 mutex_unlock(&head->mutex);
3032                 btrfs_put_delayed_ref_head(head);
3033                 btrfs_put_transaction(cur_trans);
3034                 return -EAGAIN;
3035         }
3036         spin_unlock(&delayed_refs->lock);
3037
3038         spin_lock(&head->lock);
3039         /*
3040          * XXX: We should replace this with a proper search function in the
3041          * future.
3042          */
3043         for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
3044                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
3045                 /* If it's a shared ref we know a cross reference exists */
3046                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3047                         ret = 1;
3048                         break;
3049                 }
3050
3051                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3052
3053                 /*
3054                  * If our ref doesn't match the one we're currently looking at
3055                  * then we have a cross reference.
3056                  */
3057                 if (data_ref->root != root->root_key.objectid ||
3058                     data_ref->objectid != objectid ||
3059                     data_ref->offset != offset) {
3060                         ret = 1;
3061                         break;
3062                 }
3063         }
3064         spin_unlock(&head->lock);
3065         mutex_unlock(&head->mutex);
3066         btrfs_put_transaction(cur_trans);
3067         return ret;
3068 }
3069
3070 static noinline int check_committed_ref(struct btrfs_root *root,
3071                                         struct btrfs_path *path,
3072                                         u64 objectid, u64 offset, u64 bytenr)
3073 {
3074         struct btrfs_fs_info *fs_info = root->fs_info;
3075         struct btrfs_root *extent_root = fs_info->extent_root;
3076         struct extent_buffer *leaf;
3077         struct btrfs_extent_data_ref *ref;
3078         struct btrfs_extent_inline_ref *iref;
3079         struct btrfs_extent_item *ei;
3080         struct btrfs_key key;
3081         u32 item_size;
3082         int type;
3083         int ret;
3084
3085         key.objectid = bytenr;
3086         key.offset = (u64)-1;
3087         key.type = BTRFS_EXTENT_ITEM_KEY;
3088
3089         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3090         if (ret < 0)
3091                 goto out;
3092         BUG_ON(ret == 0); /* Corruption */
3093
3094         ret = -ENOENT;
3095         if (path->slots[0] == 0)
3096                 goto out;
3097
3098         path->slots[0]--;
3099         leaf = path->nodes[0];
3100         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3101
3102         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3103                 goto out;
3104
3105         ret = 1;
3106         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3107         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3108
3109         if (item_size != sizeof(*ei) +
3110             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3111                 goto out;
3112
3113         if (btrfs_extent_generation(leaf, ei) <=
3114             btrfs_root_last_snapshot(&root->root_item))
3115                 goto out;
3116
3117         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3118
3119         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
3120         if (type != BTRFS_EXTENT_DATA_REF_KEY)
3121                 goto out;
3122
3123         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3124         if (btrfs_extent_refs(leaf, ei) !=
3125             btrfs_extent_data_ref_count(leaf, ref) ||
3126             btrfs_extent_data_ref_root(leaf, ref) !=
3127             root->root_key.objectid ||
3128             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3129             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3130                 goto out;
3131
3132         ret = 0;
3133 out:
3134         return ret;
3135 }
3136
3137 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
3138                           u64 bytenr)
3139 {
3140         struct btrfs_path *path;
3141         int ret;
3142         int ret2;
3143
3144         path = btrfs_alloc_path();
3145         if (!path)
3146                 return -ENOMEM;
3147
3148         do {
3149                 ret = check_committed_ref(root, path, objectid,
3150                                           offset, bytenr);
3151                 if (ret && ret != -ENOENT)
3152                         goto out;
3153
3154                 ret2 = check_delayed_ref(root, path, objectid,
3155                                          offset, bytenr);
3156         } while (ret2 == -EAGAIN);
3157
3158         if (ret2 && ret2 != -ENOENT) {
3159                 ret = ret2;
3160                 goto out;
3161         }
3162
3163         if (ret != -ENOENT || ret2 != -ENOENT)
3164                 ret = 0;
3165 out:
3166         btrfs_free_path(path);
3167         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3168                 WARN_ON(ret > 0);
3169         return ret;
3170 }
3171
3172 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3173                            struct btrfs_root *root,
3174                            struct extent_buffer *buf,
3175                            int full_backref, int inc)
3176 {
3177         struct btrfs_fs_info *fs_info = root->fs_info;
3178         u64 bytenr;
3179         u64 num_bytes;
3180         u64 parent;
3181         u64 ref_root;
3182         u32 nritems;
3183         struct btrfs_key key;
3184         struct btrfs_file_extent_item *fi;
3185         int i;
3186         int level;
3187         int ret = 0;
3188         int (*process_func)(struct btrfs_trans_handle *,
3189                             struct btrfs_root *,
3190                             u64, u64, u64, u64, u64, u64);
3191
3192
3193         if (btrfs_is_testing(fs_info))
3194                 return 0;
3195
3196         ref_root = btrfs_header_owner(buf);
3197         nritems = btrfs_header_nritems(buf);
3198         level = btrfs_header_level(buf);
3199
3200         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3201                 return 0;
3202
3203         if (inc)
3204                 process_func = btrfs_inc_extent_ref;
3205         else
3206                 process_func = btrfs_free_extent;
3207
3208         if (full_backref)
3209                 parent = buf->start;
3210         else
3211                 parent = 0;
3212
3213         for (i = 0; i < nritems; i++) {
3214                 if (level == 0) {
3215                         btrfs_item_key_to_cpu(buf, &key, i);
3216                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3217                                 continue;
3218                         fi = btrfs_item_ptr(buf, i,
3219                                             struct btrfs_file_extent_item);
3220                         if (btrfs_file_extent_type(buf, fi) ==
3221                             BTRFS_FILE_EXTENT_INLINE)
3222                                 continue;
3223                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3224                         if (bytenr == 0)
3225                                 continue;
3226
3227                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3228                         key.offset -= btrfs_file_extent_offset(buf, fi);
3229                         ret = process_func(trans, root, bytenr, num_bytes,
3230                                            parent, ref_root, key.objectid,
3231                                            key.offset);
3232                         if (ret)
3233                                 goto fail;
3234                 } else {
3235                         bytenr = btrfs_node_blockptr(buf, i);
3236                         num_bytes = fs_info->nodesize;
3237                         ret = process_func(trans, root, bytenr, num_bytes,
3238                                            parent, ref_root, level - 1, 0);
3239                         if (ret)
3240                                 goto fail;
3241                 }
3242         }
3243         return 0;
3244 fail:
3245         return ret;
3246 }
3247
3248 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3249                   struct extent_buffer *buf, int full_backref)
3250 {
3251         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3252 }
3253
3254 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3255                   struct extent_buffer *buf, int full_backref)
3256 {
3257         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3258 }
3259
3260 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3261                                  struct btrfs_fs_info *fs_info,
3262                                  struct btrfs_path *path,
3263                                  struct btrfs_block_group_cache *cache)
3264 {
3265         int ret;
3266         struct btrfs_root *extent_root = fs_info->extent_root;
3267         unsigned long bi;
3268         struct extent_buffer *leaf;
3269
3270         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3271         if (ret) {
3272                 if (ret > 0)
3273                         ret = -ENOENT;
3274                 goto fail;
3275         }
3276
3277         leaf = path->nodes[0];
3278         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3279         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3280         btrfs_mark_buffer_dirty(leaf);
3281 fail:
3282         btrfs_release_path(path);
3283         return ret;
3284
3285 }
3286
3287 static struct btrfs_block_group_cache *
3288 next_block_group(struct btrfs_fs_info *fs_info,
3289                  struct btrfs_block_group_cache *cache)
3290 {
3291         struct rb_node *node;
3292
3293         spin_lock(&fs_info->block_group_cache_lock);
3294
3295         /* If our block group was removed, we need a full search. */
3296         if (RB_EMPTY_NODE(&cache->cache_node)) {
3297                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3298
3299                 spin_unlock(&fs_info->block_group_cache_lock);
3300                 btrfs_put_block_group(cache);
3301                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
3302         }
3303         node = rb_next(&cache->cache_node);
3304         btrfs_put_block_group(cache);
3305         if (node) {
3306                 cache = rb_entry(node, struct btrfs_block_group_cache,
3307                                  cache_node);
3308                 btrfs_get_block_group(cache);
3309         } else
3310                 cache = NULL;
3311         spin_unlock(&fs_info->block_group_cache_lock);
3312         return cache;
3313 }
3314
3315 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3316                             struct btrfs_trans_handle *trans,
3317                             struct btrfs_path *path)
3318 {
3319         struct btrfs_fs_info *fs_info = block_group->fs_info;
3320         struct btrfs_root *root = fs_info->tree_root;
3321         struct inode *inode = NULL;
3322         struct extent_changeset *data_reserved = NULL;
3323         u64 alloc_hint = 0;
3324         int dcs = BTRFS_DC_ERROR;
3325         u64 num_pages = 0;
3326         int retries = 0;
3327         int ret = 0;
3328
3329         /*
3330          * If this block group is smaller than 100 megs don't bother caching the
3331          * block group.
3332          */
3333         if (block_group->key.offset < (100 * SZ_1M)) {
3334                 spin_lock(&block_group->lock);
3335                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3336                 spin_unlock(&block_group->lock);
3337                 return 0;
3338         }
3339
3340         if (trans->aborted)
3341                 return 0;
3342 again:
3343         inode = lookup_free_space_inode(fs_info, block_group, path);
3344         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3345                 ret = PTR_ERR(inode);
3346                 btrfs_release_path(path);
3347                 goto out;
3348         }
3349
3350         if (IS_ERR(inode)) {
3351                 BUG_ON(retries);
3352                 retries++;
3353
3354                 if (block_group->ro)
3355                         goto out_free;
3356
3357                 ret = create_free_space_inode(fs_info, trans, block_group,
3358                                               path);
3359                 if (ret)
3360                         goto out_free;
3361                 goto again;
3362         }
3363
3364         /*
3365          * We want to set the generation to 0, that way if anything goes wrong
3366          * from here on out we know not to trust this cache when we load up next
3367          * time.
3368          */
3369         BTRFS_I(inode)->generation = 0;
3370         ret = btrfs_update_inode(trans, root, inode);
3371         if (ret) {
3372                 /*
3373                  * So theoretically we could recover from this, simply set the
3374                  * super cache generation to 0 so we know to invalidate the
3375                  * cache, but then we'd have to keep track of the block groups
3376                  * that fail this way so we know we _have_ to reset this cache
3377                  * before the next commit or risk reading stale cache.  So to
3378                  * limit our exposure to horrible edge cases lets just abort the
3379                  * transaction, this only happens in really bad situations
3380                  * anyway.
3381                  */
3382                 btrfs_abort_transaction(trans, ret);
3383                 goto out_put;
3384         }
3385         WARN_ON(ret);
3386
3387         /* We've already setup this transaction, go ahead and exit */
3388         if (block_group->cache_generation == trans->transid &&
3389             i_size_read(inode)) {
3390                 dcs = BTRFS_DC_SETUP;
3391                 goto out_put;
3392         }
3393
3394         if (i_size_read(inode) > 0) {
3395                 ret = btrfs_check_trunc_cache_free_space(fs_info,
3396                                         &fs_info->global_block_rsv);
3397                 if (ret)
3398                         goto out_put;
3399
3400                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3401                 if (ret)
3402                         goto out_put;
3403         }
3404
3405         spin_lock(&block_group->lock);
3406         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3407             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3408                 /*
3409                  * don't bother trying to write stuff out _if_
3410                  * a) we're not cached,
3411                  * b) we're with nospace_cache mount option,
3412                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
3413                  */
3414                 dcs = BTRFS_DC_WRITTEN;
3415                 spin_unlock(&block_group->lock);
3416                 goto out_put;
3417         }
3418         spin_unlock(&block_group->lock);
3419
3420         /*
3421          * We hit an ENOSPC when setting up the cache in this transaction, just
3422          * skip doing the setup, we've already cleared the cache so we're safe.
3423          */
3424         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3425                 ret = -ENOSPC;
3426                 goto out_put;
3427         }
3428
3429         /*
3430          * Try to preallocate enough space based on how big the block group is.
3431          * Keep in mind this has to include any pinned space which could end up
3432          * taking up quite a bit since it's not folded into the other space
3433          * cache.
3434          */
3435         num_pages = div_u64(block_group->key.offset, SZ_256M);
3436         if (!num_pages)
3437                 num_pages = 1;
3438
3439         num_pages *= 16;
3440         num_pages *= PAGE_SIZE;
3441
3442         ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
3443         if (ret)
3444                 goto out_put;
3445
3446         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3447                                               num_pages, num_pages,
3448                                               &alloc_hint);
3449         /*
3450          * Our cache requires contiguous chunks so that we don't modify a bunch
3451          * of metadata or split extents when writing the cache out, which means
3452          * we can enospc if we are heavily fragmented in addition to just normal
3453          * out of space conditions.  So if we hit this just skip setting up any
3454          * other block groups for this transaction, maybe we'll unpin enough
3455          * space the next time around.
3456          */
3457         if (!ret)
3458                 dcs = BTRFS_DC_SETUP;
3459         else if (ret == -ENOSPC)
3460                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3461
3462 out_put:
3463         iput(inode);
3464 out_free:
3465         btrfs_release_path(path);
3466 out:
3467         spin_lock(&block_group->lock);
3468         if (!ret && dcs == BTRFS_DC_SETUP)
3469                 block_group->cache_generation = trans->transid;
3470         block_group->disk_cache_state = dcs;
3471         spin_unlock(&block_group->lock);
3472
3473         extent_changeset_free(data_reserved);
3474         return ret;
3475 }
3476
3477 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3478                             struct btrfs_fs_info *fs_info)
3479 {
3480         struct btrfs_block_group_cache *cache, *tmp;
3481         struct btrfs_transaction *cur_trans = trans->transaction;
3482         struct btrfs_path *path;
3483
3484         if (list_empty(&cur_trans->dirty_bgs) ||
3485             !btrfs_test_opt(fs_info, SPACE_CACHE))
3486                 return 0;
3487
3488         path = btrfs_alloc_path();
3489         if (!path)
3490                 return -ENOMEM;
3491
3492         /* Could add new block groups, use _safe just in case */
3493         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3494                                  dirty_list) {
3495                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3496                         cache_save_setup(cache, trans, path);
3497         }
3498
3499         btrfs_free_path(path);
3500         return 0;
3501 }
3502
3503 /*
3504  * transaction commit does final block group cache writeback during a
3505  * critical section where nothing is allowed to change the FS.  This is
3506  * required in order for the cache to actually match the block group,
3507  * but can introduce a lot of latency into the commit.
3508  *
3509  * So, btrfs_start_dirty_block_groups is here to kick off block group
3510  * cache IO.  There's a chance we'll have to redo some of it if the
3511  * block group changes again during the commit, but it greatly reduces
3512  * the commit latency by getting rid of the easy block groups while
3513  * we're still allowing others to join the commit.
3514  */
3515 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
3516 {
3517         struct btrfs_fs_info *fs_info = trans->fs_info;
3518         struct btrfs_block_group_cache *cache;
3519         struct btrfs_transaction *cur_trans = trans->transaction;
3520         int ret = 0;
3521         int should_put;
3522         struct btrfs_path *path = NULL;
3523         LIST_HEAD(dirty);
3524         struct list_head *io = &cur_trans->io_bgs;
3525         int num_started = 0;
3526         int loops = 0;
3527
3528         spin_lock(&cur_trans->dirty_bgs_lock);
3529         if (list_empty(&cur_trans->dirty_bgs)) {
3530                 spin_unlock(&cur_trans->dirty_bgs_lock);
3531                 return 0;
3532         }
3533         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3534         spin_unlock(&cur_trans->dirty_bgs_lock);
3535
3536 again:
3537         /*
3538          * make sure all the block groups on our dirty list actually
3539          * exist
3540          */
3541         btrfs_create_pending_block_groups(trans);
3542
3543         if (!path) {
3544                 path = btrfs_alloc_path();
3545                 if (!path)
3546                         return -ENOMEM;
3547         }
3548
3549         /*
3550          * cache_write_mutex is here only to save us from balance or automatic
3551          * removal of empty block groups deleting this block group while we are
3552          * writing out the cache
3553          */
3554         mutex_lock(&trans->transaction->cache_write_mutex);
3555         while (!list_empty(&dirty)) {
3556                 cache = list_first_entry(&dirty,
3557                                          struct btrfs_block_group_cache,
3558                                          dirty_list);
3559                 /*
3560                  * this can happen if something re-dirties a block
3561                  * group that is already under IO.  Just wait for it to
3562                  * finish and then do it all again
3563                  */
3564                 if (!list_empty(&cache->io_list)) {
3565                         list_del_init(&cache->io_list);
3566                         btrfs_wait_cache_io(trans, cache, path);
3567                         btrfs_put_block_group(cache);
3568                 }
3569
3570
3571                 /*
3572                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3573                  * if it should update the cache_state.  Don't delete
3574                  * until after we wait.
3575                  *
3576                  * Since we're not running in the commit critical section
3577                  * we need the dirty_bgs_lock to protect from update_block_group
3578                  */
3579                 spin_lock(&cur_trans->dirty_bgs_lock);
3580                 list_del_init(&cache->dirty_list);
3581                 spin_unlock(&cur_trans->dirty_bgs_lock);
3582
3583                 should_put = 1;
3584
3585                 cache_save_setup(cache, trans, path);
3586
3587                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3588                         cache->io_ctl.inode = NULL;
3589                         ret = btrfs_write_out_cache(fs_info, trans,
3590                                                     cache, path);
3591                         if (ret == 0 && cache->io_ctl.inode) {
3592                                 num_started++;
3593                                 should_put = 0;
3594
3595                                 /*
3596                                  * The cache_write_mutex is protecting the
3597                                  * io_list, also refer to the definition of
3598                                  * btrfs_transaction::io_bgs for more details
3599                                  */
3600                                 list_add_tail(&cache->io_list, io);
3601                         } else {
3602                                 /*
3603                                  * if we failed to write the cache, the
3604                                  * generation will be bad and life goes on
3605                                  */
3606                                 ret = 0;
3607                         }
3608                 }
3609                 if (!ret) {
3610                         ret = write_one_cache_group(trans, fs_info,
3611                                                     path, cache);
3612                         /*
3613                          * Our block group might still be attached to the list
3614                          * of new block groups in the transaction handle of some
3615                          * other task (struct btrfs_trans_handle->new_bgs). This
3616                          * means its block group item isn't yet in the extent
3617                          * tree. If this happens ignore the error, as we will
3618                          * try again later in the critical section of the
3619                          * transaction commit.
3620                          */
3621                         if (ret == -ENOENT) {
3622                                 ret = 0;
3623                                 spin_lock(&cur_trans->dirty_bgs_lock);
3624                                 if (list_empty(&cache->dirty_list)) {
3625                                         list_add_tail(&cache->dirty_list,
3626                                                       &cur_trans->dirty_bgs);
3627                                         btrfs_get_block_group(cache);
3628                                 }
3629                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3630                         } else if (ret) {
3631                                 btrfs_abort_transaction(trans, ret);
3632                         }
3633                 }
3634
3635                 /* if its not on the io list, we need to put the block group */
3636                 if (should_put)
3637                         btrfs_put_block_group(cache);
3638
3639                 if (ret)
3640                         break;
3641
3642                 /*
3643                  * Avoid blocking other tasks for too long. It might even save
3644                  * us from writing caches for block groups that are going to be
3645                  * removed.
3646                  */
3647                 mutex_unlock(&trans->transaction->cache_write_mutex);
3648                 mutex_lock(&trans->transaction->cache_write_mutex);
3649         }
3650         mutex_unlock(&trans->transaction->cache_write_mutex);
3651
3652         /*
3653          * go through delayed refs for all the stuff we've just kicked off
3654          * and then loop back (just once)
3655          */
3656         ret = btrfs_run_delayed_refs(trans, 0);
3657         if (!ret && loops == 0) {
3658                 loops++;
3659                 spin_lock(&cur_trans->dirty_bgs_lock);
3660                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3661                 /*
3662                  * dirty_bgs_lock protects us from concurrent block group
3663                  * deletes too (not just cache_write_mutex).
3664                  */
3665                 if (!list_empty(&dirty)) {
3666                         spin_unlock(&cur_trans->dirty_bgs_lock);
3667                         goto again;
3668                 }
3669                 spin_unlock(&cur_trans->dirty_bgs_lock);
3670         } else if (ret < 0) {
3671                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3672         }
3673
3674         btrfs_free_path(path);
3675         return ret;
3676 }
3677
3678 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3679                                    struct btrfs_fs_info *fs_info)
3680 {
3681         struct btrfs_block_group_cache *cache;
3682         struct btrfs_transaction *cur_trans = trans->transaction;
3683         int ret = 0;
3684         int should_put;
3685         struct btrfs_path *path;
3686         struct list_head *io = &cur_trans->io_bgs;
3687         int num_started = 0;
3688
3689         path = btrfs_alloc_path();
3690         if (!path)
3691                 return -ENOMEM;
3692
3693         /*
3694          * Even though we are in the critical section of the transaction commit,
3695          * we can still have concurrent tasks adding elements to this
3696          * transaction's list of dirty block groups. These tasks correspond to
3697          * endio free space workers started when writeback finishes for a
3698          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3699          * allocate new block groups as a result of COWing nodes of the root
3700          * tree when updating the free space inode. The writeback for the space
3701          * caches is triggered by an earlier call to
3702          * btrfs_start_dirty_block_groups() and iterations of the following
3703          * loop.
3704          * Also we want to do the cache_save_setup first and then run the
3705          * delayed refs to make sure we have the best chance at doing this all
3706          * in one shot.
3707          */
3708         spin_lock(&cur_trans->dirty_bgs_lock);
3709         while (!list_empty(&cur_trans->dirty_bgs)) {
3710                 cache = list_first_entry(&cur_trans->dirty_bgs,
3711                                          struct btrfs_block_group_cache,
3712                                          dirty_list);
3713
3714                 /*
3715                  * this can happen if cache_save_setup re-dirties a block
3716                  * group that is already under IO.  Just wait for it to
3717                  * finish and then do it all again
3718                  */
3719                 if (!list_empty(&cache->io_list)) {
3720                         spin_unlock(&cur_trans->dirty_bgs_lock);
3721                         list_del_init(&cache->io_list);
3722                         btrfs_wait_cache_io(trans, cache, path);
3723                         btrfs_put_block_group(cache);
3724                         spin_lock(&cur_trans->dirty_bgs_lock);
3725                 }
3726
3727                 /*
3728                  * don't remove from the dirty list until after we've waited
3729                  * on any pending IO
3730                  */
3731                 list_del_init(&cache->dirty_list);
3732                 spin_unlock(&cur_trans->dirty_bgs_lock);
3733                 should_put = 1;
3734
3735                 cache_save_setup(cache, trans, path);
3736
3737                 if (!ret)
3738                         ret = btrfs_run_delayed_refs(trans,
3739                                                      (unsigned long) -1);
3740
3741                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3742                         cache->io_ctl.inode = NULL;
3743                         ret = btrfs_write_out_cache(fs_info, trans,
3744                                                     cache, path);
3745                         if (ret == 0 && cache->io_ctl.inode) {
3746                                 num_started++;
3747                                 should_put = 0;
3748                                 list_add_tail(&cache->io_list, io);
3749                         } else {
3750                                 /*
3751                                  * if we failed to write the cache, the
3752                                  * generation will be bad and life goes on
3753                                  */
3754                                 ret = 0;
3755                         }
3756                 }
3757                 if (!ret) {
3758                         ret = write_one_cache_group(trans, fs_info,
3759                                                     path, cache);
3760                         /*
3761                          * One of the free space endio workers might have
3762                          * created a new block group while updating a free space
3763                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3764                          * and hasn't released its transaction handle yet, in
3765                          * which case the new block group is still attached to
3766                          * its transaction handle and its creation has not
3767                          * finished yet (no block group item in the extent tree
3768                          * yet, etc). If this is the case, wait for all free
3769                          * space endio workers to finish and retry. This is a
3770                          * a very rare case so no need for a more efficient and
3771                          * complex approach.
3772                          */
3773                         if (ret == -ENOENT) {
3774                                 wait_event(cur_trans->writer_wait,
3775                                    atomic_read(&cur_trans->num_writers) == 1);
3776                                 ret = write_one_cache_group(trans, fs_info,
3777                                                             path, cache);
3778                         }
3779                         if (ret)
3780                                 btrfs_abort_transaction(trans, ret);
3781                 }
3782
3783                 /* if its not on the io list, we need to put the block group */
3784                 if (should_put)
3785                         btrfs_put_block_group(cache);
3786                 spin_lock(&cur_trans->dirty_bgs_lock);
3787         }
3788         spin_unlock(&cur_trans->dirty_bgs_lock);
3789
3790         /*
3791          * Refer to the definition of io_bgs member for details why it's safe
3792          * to use it without any locking
3793          */
3794         while (!list_empty(io)) {
3795                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3796                                          io_list);
3797                 list_del_init(&cache->io_list);
3798                 btrfs_wait_cache_io(trans, cache, path);
3799                 btrfs_put_block_group(cache);
3800         }
3801
3802         btrfs_free_path(path);
3803         return ret;
3804 }
3805
3806 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
3807 {
3808         struct btrfs_block_group_cache *block_group;
3809         int readonly = 0;
3810
3811         block_group = btrfs_lookup_block_group(fs_info, bytenr);
3812         if (!block_group || block_group->ro)
3813                 readonly = 1;
3814         if (block_group)
3815                 btrfs_put_block_group(block_group);
3816         return readonly;
3817 }
3818
3819 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3820 {
3821         struct btrfs_block_group_cache *bg;
3822         bool ret = true;
3823
3824         bg = btrfs_lookup_block_group(fs_info, bytenr);
3825         if (!bg)
3826                 return false;
3827
3828         spin_lock(&bg->lock);
3829         if (bg->ro)
3830                 ret = false;
3831         else
3832                 atomic_inc(&bg->nocow_writers);
3833         spin_unlock(&bg->lock);
3834
3835         /* no put on block group, done by btrfs_dec_nocow_writers */
3836         if (!ret)
3837                 btrfs_put_block_group(bg);
3838
3839         return ret;
3840
3841 }
3842
3843 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3844 {
3845         struct btrfs_block_group_cache *bg;
3846
3847         bg = btrfs_lookup_block_group(fs_info, bytenr);
3848         ASSERT(bg);
3849         if (atomic_dec_and_test(&bg->nocow_writers))
3850                 wake_up_var(&bg->nocow_writers);
3851         /*
3852          * Once for our lookup and once for the lookup done by a previous call
3853          * to btrfs_inc_nocow_writers()
3854          */
3855         btrfs_put_block_group(bg);
3856         btrfs_put_block_group(bg);
3857 }
3858
3859 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3860 {
3861         wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
3862 }
3863
3864 static const char *alloc_name(u64 flags)
3865 {
3866         switch (flags) {
3867         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3868                 return "mixed";
3869         case BTRFS_BLOCK_GROUP_METADATA:
3870                 return "metadata";
3871         case BTRFS_BLOCK_GROUP_DATA:
3872                 return "data";
3873         case BTRFS_BLOCK_GROUP_SYSTEM:
3874                 return "system";
3875         default:
3876                 WARN_ON(1);
3877                 return "invalid-combination";
3878         };
3879 }
3880
3881 static int create_space_info(struct btrfs_fs_info *info, u64 flags)
3882 {
3883
3884         struct btrfs_space_info *space_info;
3885         int i;
3886         int ret;
3887
3888         space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
3889         if (!space_info)
3890                 return -ENOMEM;
3891
3892         ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
3893                                  GFP_KERNEL);
3894         if (ret) {
3895                 kfree(space_info);
3896                 return ret;
3897         }
3898
3899         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3900                 INIT_LIST_HEAD(&space_info->block_groups[i]);
3901         init_rwsem(&space_info->groups_sem);
3902         spin_lock_init(&space_info->lock);
3903         space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3904         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3905         init_waitqueue_head(&space_info->wait);
3906         INIT_LIST_HEAD(&space_info->ro_bgs);
3907         INIT_LIST_HEAD(&space_info->tickets);
3908         INIT_LIST_HEAD(&space_info->priority_tickets);
3909
3910         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
3911                                     info->space_info_kobj, "%s",
3912                                     alloc_name(space_info->flags));
3913         if (ret) {
3914                 percpu_counter_destroy(&space_info->total_bytes_pinned);
3915                 kfree(space_info);
3916                 return ret;
3917         }
3918
3919         list_add_rcu(&space_info->list, &info->space_info);
3920         if (flags & BTRFS_BLOCK_GROUP_DATA)
3921                 info->data_sinfo = space_info;
3922
3923         return ret;
3924 }
3925
3926 static void update_space_info(struct btrfs_fs_info *info, u64 flags,
3927                              u64 total_bytes, u64 bytes_used,
3928                              u64 bytes_readonly,
3929                              struct btrfs_space_info **space_info)
3930 {
3931         struct btrfs_space_info *found;
3932         int factor;
3933
3934         factor = btrfs_bg_type_to_factor(flags);
3935
3936         found = __find_space_info(info, flags);
3937         ASSERT(found);
3938         spin_lock(&found->lock);
3939         found->total_bytes += total_bytes;
3940         found->disk_total += total_bytes * factor;
3941         found->bytes_used += bytes_used;
3942         found->disk_used += bytes_used * factor;
3943         found->bytes_readonly += bytes_readonly;
3944         if (total_bytes > 0)
3945                 found->full = 0;
3946         space_info_add_new_bytes(info, found, total_bytes -
3947                                  bytes_used - bytes_readonly);
3948         spin_unlock(&found->lock);
3949         *space_info = found;
3950 }
3951
3952 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3953 {
3954         u64 extra_flags = chunk_to_extended(flags) &
3955                                 BTRFS_EXTENDED_PROFILE_MASK;
3956
3957         write_seqlock(&fs_info->profiles_lock);
3958         if (flags & BTRFS_BLOCK_GROUP_DATA)
3959                 fs_info->avail_data_alloc_bits |= extra_flags;
3960         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3961                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3962         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3963                 fs_info->avail_system_alloc_bits |= extra_flags;
3964         write_sequnlock(&fs_info->profiles_lock);
3965 }
3966
3967 /*
3968  * returns target flags in extended format or 0 if restripe for this
3969  * chunk_type is not in progress
3970  *
3971  * should be called with balance_lock held
3972  */
3973 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3974 {
3975         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3976         u64 target = 0;
3977
3978         if (!bctl)
3979                 return 0;
3980
3981         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3982             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3983                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3984         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3985                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3986                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3987         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3988                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3989                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3990         }
3991
3992         return target;
3993 }
3994
3995 /*
3996  * @flags: available profiles in extended format (see ctree.h)
3997  *
3998  * Returns reduced profile in chunk format.  If profile changing is in
3999  * progress (either running or paused) picks the target profile (if it's
4000  * already available), otherwise falls back to plain reducing.
4001  */
4002 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
4003 {
4004         u64 num_devices = fs_info->fs_devices->rw_devices;
4005         u64 target;
4006         u64 raid_type;
4007         u64 allowed = 0;
4008
4009         /*
4010          * see if restripe for this chunk_type is in progress, if so
4011          * try to reduce to the target profile
4012          */
4013         spin_lock(&fs_info->balance_lock);
4014         target = get_restripe_target(fs_info, flags);
4015         if (target) {
4016                 /* pick target profile only if it's already available */
4017                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4018                         spin_unlock(&fs_info->balance_lock);
4019                         return extended_to_chunk(target);
4020                 }
4021         }
4022         spin_unlock(&fs_info->balance_lock);
4023
4024         /* First, mask out the RAID levels which aren't possible */
4025         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4026                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4027                         allowed |= btrfs_raid_array[raid_type].bg_flag;
4028         }
4029         allowed &= flags;
4030
4031         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4032                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4033         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4034                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4035         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4036                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4037         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4038                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4039         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4040                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4041
4042         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4043
4044         return extended_to_chunk(flags | allowed);
4045 }
4046
4047 static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
4048 {
4049         unsigned seq;
4050         u64 flags;
4051
4052         do {
4053                 flags = orig_flags;
4054                 seq = read_seqbegin(&fs_info->profiles_lock);
4055
4056                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4057                         flags |= fs_info->avail_data_alloc_bits;
4058                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4059                         flags |= fs_info->avail_system_alloc_bits;
4060                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4061                         flags |= fs_info->avail_metadata_alloc_bits;
4062         } while (read_seqretry(&fs_info->profiles_lock, seq));
4063
4064         return btrfs_reduce_alloc_profile(fs_info, flags);
4065 }
4066
4067 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
4068 {
4069         struct btrfs_fs_info *fs_info = root->fs_info;
4070         u64 flags;
4071         u64 ret;
4072
4073         if (data)
4074                 flags = BTRFS_BLOCK_GROUP_DATA;
4075         else if (root == fs_info->chunk_root)
4076                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4077         else
4078                 flags = BTRFS_BLOCK_GROUP_METADATA;
4079
4080         ret = get_alloc_profile(fs_info, flags);
4081         return ret;
4082 }
4083
4084 u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
4085 {
4086         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
4087 }
4088
4089 u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
4090 {
4091         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4092 }
4093
4094 u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
4095 {
4096         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4097 }
4098
4099 static u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
4100                                  bool may_use_included)
4101 {
4102         ASSERT(s_info);
4103         return s_info->bytes_used + s_info->bytes_reserved +
4104                 s_info->bytes_pinned + s_info->bytes_readonly +
4105                 (may_use_included ? s_info->bytes_may_use : 0);
4106 }
4107
4108 int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes)
4109 {
4110         struct btrfs_root *root = inode->root;
4111         struct btrfs_fs_info *fs_info = root->fs_info;
4112         struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
4113         u64 used;
4114         int ret = 0;
4115         int need_commit = 2;
4116         int have_pinned_space;
4117
4118         /* make sure bytes are sectorsize aligned */
4119         bytes = ALIGN(bytes, fs_info->sectorsize);
4120
4121         if (btrfs_is_free_space_inode(inode)) {
4122                 need_commit = 0;
4123                 ASSERT(current->journal_info);
4124         }
4125
4126 again:
4127         /* make sure we have enough space to handle the data first */
4128         spin_lock(&data_sinfo->lock);
4129         used = btrfs_space_info_used(data_sinfo, true);
4130
4131         if (used + bytes > data_sinfo->total_bytes) {
4132                 struct btrfs_trans_handle *trans;
4133
4134                 /*
4135                  * if we don't have enough free bytes in this space then we need
4136                  * to alloc a new chunk.
4137                  */
4138                 if (!data_sinfo->full) {
4139                         u64 alloc_target;
4140
4141                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4142                         spin_unlock(&data_sinfo->lock);
4143
4144                         alloc_target = btrfs_data_alloc_profile(fs_info);
4145                         /*
4146                          * It is ugly that we don't call nolock join
4147                          * transaction for the free space inode case here.
4148                          * But it is safe because we only do the data space
4149                          * reservation for the free space cache in the
4150                          * transaction context, the common join transaction
4151                          * just increase the counter of the current transaction
4152                          * handler, doesn't try to acquire the trans_lock of
4153                          * the fs.
4154                          */
4155                         trans = btrfs_join_transaction(root);
4156                         if (IS_ERR(trans))
4157                                 return PTR_ERR(trans);
4158
4159                         ret = do_chunk_alloc(trans, alloc_target,
4160                                              CHUNK_ALLOC_NO_FORCE);
4161                         btrfs_end_transaction(trans);
4162                         if (ret < 0) {
4163                                 if (ret != -ENOSPC)
4164                                         return ret;
4165                                 else {
4166                                         have_pinned_space = 1;
4167                                         goto commit_trans;
4168                                 }
4169                         }
4170
4171                         goto again;
4172                 }
4173
4174                 /*
4175                  * If we don't have enough pinned space to deal with this
4176                  * allocation, and no removed chunk in current transaction,
4177                  * don't bother committing the transaction.
4178                  */
4179                 have_pinned_space = __percpu_counter_compare(
4180                         &data_sinfo->total_bytes_pinned,
4181                         used + bytes - data_sinfo->total_bytes,
4182                         BTRFS_TOTAL_BYTES_PINNED_BATCH);
4183                 spin_unlock(&data_sinfo->lock);
4184
4185                 /* commit the current transaction and try again */
4186 commit_trans:
4187                 if (need_commit) {
4188                         need_commit--;
4189
4190                         if (need_commit > 0) {
4191                                 btrfs_start_delalloc_roots(fs_info, -1);
4192                                 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
4193                                                          (u64)-1);
4194                         }
4195
4196                         trans = btrfs_join_transaction(root);
4197                         if (IS_ERR(trans))
4198                                 return PTR_ERR(trans);
4199                         if (have_pinned_space >= 0 ||
4200                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4201                                      &trans->transaction->flags) ||
4202                             need_commit > 0) {
4203                                 ret = btrfs_commit_transaction(trans);
4204                                 if (ret)
4205                                         return ret;
4206                                 /*
4207                                  * The cleaner kthread might still be doing iput
4208                                  * operations. Wait for it to finish so that
4209                                  * more space is released.
4210                                  */
4211                                 mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
4212                                 mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
4213                                 goto again;
4214                         } else {
4215                                 btrfs_end_transaction(trans);
4216                         }
4217                 }
4218
4219                 trace_btrfs_space_reservation(fs_info,
4220                                               "space_info:enospc",
4221                                               data_sinfo->flags, bytes, 1);
4222                 return -ENOSPC;
4223         }
4224         data_sinfo->bytes_may_use += bytes;
4225         trace_btrfs_space_reservation(fs_info, "space_info",
4226                                       data_sinfo->flags, bytes, 1);
4227         spin_unlock(&data_sinfo->lock);
4228
4229         return 0;
4230 }
4231
4232 int btrfs_check_data_free_space(struct inode *inode,
4233                         struct extent_changeset **reserved, u64 start, u64 len)
4234 {
4235         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4236         int ret;
4237
4238         /* align the range */
4239         len = round_up(start + len, fs_info->sectorsize) -
4240               round_down(start, fs_info->sectorsize);
4241         start = round_down(start, fs_info->sectorsize);
4242
4243         ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), len);
4244         if (ret < 0)
4245                 return ret;
4246
4247         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4248         ret = btrfs_qgroup_reserve_data(inode, reserved, start, len);
4249         if (ret < 0)
4250                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4251         else
4252                 ret = 0;
4253         return ret;
4254 }
4255
4256 /*
4257  * Called if we need to clear a data reservation for this inode
4258  * Normally in a error case.
4259  *
4260  * This one will *NOT* use accurate qgroup reserved space API, just for case
4261  * which we can't sleep and is sure it won't affect qgroup reserved space.
4262  * Like clear_bit_hook().
4263  */
4264 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4265                                             u64 len)
4266 {
4267         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4268         struct btrfs_space_info *data_sinfo;
4269
4270         /* Make sure the range is aligned to sectorsize */
4271         len = round_up(start + len, fs_info->sectorsize) -
4272               round_down(start, fs_info->sectorsize);
4273         start = round_down(start, fs_info->sectorsize);
4274
4275         data_sinfo = fs_info->data_sinfo;
4276         spin_lock(&data_sinfo->lock);
4277         if (WARN_ON(data_sinfo->bytes_may_use < len))
4278                 data_sinfo->bytes_may_use = 0;
4279         else
4280                 data_sinfo->bytes_may_use -= len;
4281         trace_btrfs_space_reservation(fs_info, "space_info",
4282                                       data_sinfo->flags, len, 0);
4283         spin_unlock(&data_sinfo->lock);
4284 }
4285
4286 /*
4287  * Called if we need to clear a data reservation for this inode
4288  * Normally in a error case.
4289  *
4290  * This one will handle the per-inode data rsv map for accurate reserved
4291  * space framework.
4292  */
4293 void btrfs_free_reserved_data_space(struct inode *inode,
4294                         struct extent_changeset *reserved, u64 start, u64 len)
4295 {
4296         struct btrfs_root *root = BTRFS_I(inode)->root;
4297
4298         /* Make sure the range is aligned to sectorsize */
4299         len = round_up(start + len, root->fs_info->sectorsize) -
4300               round_down(start, root->fs_info->sectorsize);
4301         start = round_down(start, root->fs_info->sectorsize);
4302
4303         btrfs_free_reserved_data_space_noquota(inode, start, len);
4304         btrfs_qgroup_free_data(inode, reserved, start, len);
4305 }
4306
4307 static void force_metadata_allocation(struct btrfs_fs_info *info)
4308 {
4309         struct list_head *head = &info->space_info;
4310         struct btrfs_space_info *found;
4311
4312         rcu_read_lock();
4313         list_for_each_entry_rcu(found, head, list) {
4314                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4315                         found->force_alloc = CHUNK_ALLOC_FORCE;
4316         }
4317         rcu_read_unlock();
4318 }
4319
4320 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4321 {
4322         return (global->size << 1);
4323 }
4324
4325 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
4326                               struct btrfs_space_info *sinfo, int force)
4327 {
4328         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4329         u64 bytes_used = btrfs_space_info_used(sinfo, false);
4330         u64 thresh;
4331
4332         if (force == CHUNK_ALLOC_FORCE)
4333                 return 1;
4334
4335         /*
4336          * We need to take into account the global rsv because for all intents
4337          * and purposes it's used space.  Don't worry about locking the
4338          * global_rsv, it doesn't change except when the transaction commits.
4339          */
4340         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4341                 bytes_used += calc_global_rsv_need_space(global_rsv);
4342
4343         /*
4344          * in limited mode, we want to have some free space up to
4345          * about 1% of the FS size.
4346          */
4347         if (force == CHUNK_ALLOC_LIMITED) {
4348                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
4349                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4350
4351                 if (sinfo->total_bytes - bytes_used < thresh)
4352                         return 1;
4353         }
4354
4355         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
4356                 return 0;
4357         return 1;
4358 }
4359
4360 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4361 {
4362         u64 num_dev;
4363
4364         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4365                     BTRFS_BLOCK_GROUP_RAID0 |
4366                     BTRFS_BLOCK_GROUP_RAID5 |
4367                     BTRFS_BLOCK_GROUP_RAID6))
4368                 num_dev = fs_info->fs_devices->rw_devices;
4369         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4370                 num_dev = 2;
4371         else
4372                 num_dev = 1;    /* DUP or single */
4373
4374         return num_dev;
4375 }
4376
4377 /*
4378  * If @is_allocation is true, reserve space in the system space info necessary
4379  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4380  * removing a chunk.
4381  */
4382 void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
4383 {
4384         struct btrfs_fs_info *fs_info = trans->fs_info;
4385         struct btrfs_space_info *info;
4386         u64 left;
4387         u64 thresh;
4388         int ret = 0;
4389         u64 num_devs;
4390
4391         /*
4392          * Needed because we can end up allocating a system chunk and for an
4393          * atomic and race free space reservation in the chunk block reserve.
4394          */
4395         lockdep_assert_held(&fs_info->chunk_mutex);
4396
4397         info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4398         spin_lock(&info->lock);
4399         left = info->total_bytes - btrfs_space_info_used(info, true);
4400         spin_unlock(&info->lock);
4401
4402         num_devs = get_profile_num_devs(fs_info, type);
4403
4404         /* num_devs device items to update and 1 chunk item to add or remove */
4405         thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
4406                 btrfs_calc_trans_metadata_size(fs_info, 1);
4407
4408         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4409                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4410                            left, thresh, type);
4411                 dump_space_info(fs_info, info, 0, 0);
4412         }
4413
4414         if (left < thresh) {
4415                 u64 flags = btrfs_system_alloc_profile(fs_info);
4416
4417                 /*
4418                  * Ignore failure to create system chunk. We might end up not
4419                  * needing it, as we might not need to COW all nodes/leafs from
4420                  * the paths we visit in the chunk tree (they were already COWed
4421                  * or created in the current transaction for example).
4422                  */
4423                 ret = btrfs_alloc_chunk(trans, flags);
4424         }
4425
4426         if (!ret) {
4427                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
4428                                           &fs_info->chunk_block_rsv,
4429                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4430                 if (!ret)
4431                         trans->chunk_bytes_reserved += thresh;
4432         }
4433 }
4434
4435 /*
4436  * If force is CHUNK_ALLOC_FORCE:
4437  *    - return 1 if it successfully allocates a chunk,
4438  *    - return errors including -ENOSPC otherwise.
4439  * If force is NOT CHUNK_ALLOC_FORCE:
4440  *    - return 0 if it doesn't need to allocate a new chunk,
4441  *    - return 1 if it successfully allocates a chunk,
4442  *    - return errors including -ENOSPC otherwise.
4443  */
4444 static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
4445                           int force)
4446 {
4447         struct btrfs_fs_info *fs_info = trans->fs_info;
4448         struct btrfs_space_info *space_info;
4449         bool wait_for_alloc = false;
4450         bool should_alloc = false;
4451         int ret = 0;
4452
4453         /* Don't re-enter if we're already allocating a chunk */
4454         if (trans->allocating_chunk)
4455                 return -ENOSPC;
4456
4457         space_info = __find_space_info(fs_info, flags);
4458         ASSERT(space_info);
4459
4460         do {
4461                 spin_lock(&space_info->lock);
4462                 if (force < space_info->force_alloc)
4463                         force = space_info->force_alloc;
4464                 should_alloc = should_alloc_chunk(fs_info, space_info, force);
4465                 if (space_info->full) {
4466                         /* No more free physical space */
4467                         if (should_alloc)
4468                                 ret = -ENOSPC;
4469                         else
4470                                 ret = 0;
4471                         spin_unlock(&space_info->lock);
4472                         return ret;
4473                 } else if (!should_alloc) {
4474                         spin_unlock(&space_info->lock);
4475                         return 0;
4476                 } else if (space_info->chunk_alloc) {
4477                         /*
4478                          * Someone is already allocating, so we need to block
4479                          * until this someone is finished and then loop to
4480                          * recheck if we should continue with our allocation
4481                          * attempt.
4482                          */
4483                         wait_for_alloc = true;
4484                         spin_unlock(&space_info->lock);
4485                         mutex_lock(&fs_info->chunk_mutex);
4486                         mutex_unlock(&fs_info->chunk_mutex);
4487                 } else {
4488                         /* Proceed with allocation */
4489                         space_info->chunk_alloc = 1;
4490                         wait_for_alloc = false;
4491                         spin_unlock(&space_info->lock);
4492                 }
4493
4494                 cond_resched();
4495         } while (wait_for_alloc);
4496
4497         mutex_lock(&fs_info->chunk_mutex);
4498         trans->allocating_chunk = true;
4499
4500         /*
4501          * If we have mixed data/metadata chunks we want to make sure we keep
4502          * allocating mixed chunks instead of individual chunks.
4503          */
4504         if (btrfs_mixed_space_info(space_info))
4505                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4506
4507         /*
4508          * if we're doing a data chunk, go ahead and make sure that
4509          * we keep a reasonable number of metadata chunks allocated in the
4510          * FS as well.
4511          */
4512         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4513                 fs_info->data_chunk_allocations++;
4514                 if (!(fs_info->data_chunk_allocations %
4515                       fs_info->metadata_ratio))
4516                         force_metadata_allocation(fs_info);
4517         }
4518
4519         /*
4520          * Check if we have enough space in SYSTEM chunk because we may need
4521          * to update devices.
4522          */
4523         check_system_chunk(trans, flags);
4524
4525         ret = btrfs_alloc_chunk(trans, flags);
4526         trans->allocating_chunk = false;
4527
4528         spin_lock(&space_info->lock);
4529         if (ret < 0) {
4530                 if (ret == -ENOSPC)
4531                         space_info->full = 1;
4532                 else
4533                         goto out;
4534         } else {
4535                 ret = 1;
4536         }
4537
4538         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4539 out:
4540         space_info->chunk_alloc = 0;
4541         spin_unlock(&space_info->lock);
4542         mutex_unlock(&fs_info->chunk_mutex);
4543         /*
4544          * When we allocate a new chunk we reserve space in the chunk block
4545          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4546          * add new nodes/leafs to it if we end up needing to do it when
4547          * inserting the chunk item and updating device items as part of the
4548          * second phase of chunk allocation, performed by
4549          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4550          * large number of new block groups to create in our transaction
4551          * handle's new_bgs list to avoid exhausting the chunk block reserve
4552          * in extreme cases - like having a single transaction create many new
4553          * block groups when starting to write out the free space caches of all
4554          * the block groups that were made dirty during the lifetime of the
4555          * transaction.
4556          */
4557         if (trans->can_flush_pending_bgs &&
4558             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4559                 btrfs_create_pending_block_groups(trans);
4560                 btrfs_trans_release_chunk_metadata(trans);
4561         }
4562         return ret;
4563 }
4564
4565 static int can_overcommit(struct btrfs_fs_info *fs_info,
4566                           struct btrfs_space_info *space_info, u64 bytes,
4567                           enum btrfs_reserve_flush_enum flush,
4568                           bool system_chunk)
4569 {
4570         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4571         u64 profile;
4572         u64 space_size;
4573         u64 avail;
4574         u64 used;
4575         int factor;
4576
4577         /* Don't overcommit when in mixed mode. */
4578         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4579                 return 0;
4580
4581         if (system_chunk)
4582                 profile = btrfs_system_alloc_profile(fs_info);
4583         else
4584                 profile = btrfs_metadata_alloc_profile(fs_info);
4585
4586         used = btrfs_space_info_used(space_info, false);
4587
4588         /*
4589          * We only want to allow over committing if we have lots of actual space
4590          * free, but if we don't have enough space to handle the global reserve
4591          * space then we could end up having a real enospc problem when trying
4592          * to allocate a chunk or some other such important allocation.
4593          */
4594         spin_lock(&global_rsv->lock);
4595         space_size = calc_global_rsv_need_space(global_rsv);
4596         spin_unlock(&global_rsv->lock);
4597         if (used + space_size >= space_info->total_bytes)
4598                 return 0;
4599
4600         used += space_info->bytes_may_use;
4601
4602         avail = atomic64_read(&fs_info->free_chunk_space);
4603
4604         /*
4605          * If we have dup, raid1 or raid10 then only half of the free
4606          * space is actually useable.  For raid56, the space info used
4607          * doesn't include the parity drive, so we don't have to
4608          * change the math
4609          */
4610         factor = btrfs_bg_type_to_factor(profile);
4611         avail = div_u64(avail, factor);
4612
4613         /*
4614          * If we aren't flushing all things, let us overcommit up to
4615          * 1/2th of the space. If we can flush, don't let us overcommit
4616          * too much, let it overcommit up to 1/8 of the space.
4617          */
4618         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4619                 avail >>= 3;
4620         else
4621                 avail >>= 1;
4622
4623         if (used + bytes < space_info->total_bytes + avail)
4624                 return 1;
4625         return 0;
4626 }
4627
4628 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
4629                                          unsigned long nr_pages, int nr_items)
4630 {
4631         struct super_block *sb = fs_info->sb;
4632
4633         if (down_read_trylock(&sb->s_umount)) {
4634                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4635                 up_read(&sb->s_umount);
4636         } else {
4637                 /*
4638                  * We needn't worry the filesystem going from r/w to r/o though
4639                  * we don't acquire ->s_umount mutex, because the filesystem
4640                  * should guarantee the delalloc inodes list be empty after
4641                  * the filesystem is readonly(all dirty pages are written to
4642                  * the disk).
4643                  */
4644                 btrfs_start_delalloc_roots(fs_info, nr_items);
4645                 if (!current->journal_info)
4646                         btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
4647         }
4648 }
4649
4650 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
4651                                         u64 to_reclaim)
4652 {
4653         u64 bytes;
4654         u64 nr;
4655
4656         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
4657         nr = div64_u64(to_reclaim, bytes);
4658         if (!nr)
4659                 nr = 1;
4660         return nr;
4661 }
4662
4663 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4664
4665 /*
4666  * shrink metadata reservation for delalloc
4667  */
4668 static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
4669                             u64 orig, bool wait_ordered)
4670 {
4671         struct btrfs_space_info *space_info;
4672         struct btrfs_trans_handle *trans;
4673         u64 delalloc_bytes;
4674         u64 max_reclaim;
4675         u64 items;
4676         long time_left;
4677         unsigned long nr_pages;
4678         int loops;
4679
4680         /* Calc the number of the pages we need flush for space reservation */
4681         items = calc_reclaim_items_nr(fs_info, to_reclaim);
4682         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4683
4684         trans = (struct btrfs_trans_handle *)current->journal_info;
4685         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4686
4687         delalloc_bytes = percpu_counter_sum_positive(
4688                                                 &fs_info->delalloc_bytes);
4689         if (delalloc_bytes == 0) {
4690                 if (trans)
4691                         return;
4692                 if (wait_ordered)
4693                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4694                 return;
4695         }
4696
4697         loops = 0;
4698         while (delalloc_bytes && loops < 3) {
4699                 max_reclaim = min(delalloc_bytes, to_reclaim);
4700                 nr_pages = max_reclaim >> PAGE_SHIFT;
4701                 btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
4702                 /*
4703                  * We need to wait for the async pages to actually start before
4704                  * we do anything.
4705                  */
4706                 max_reclaim = atomic_read(&fs_info->async_delalloc_pages);
4707                 if (!max_reclaim)
4708                         goto skip_async;
4709
4710                 if (max_reclaim <= nr_pages)
4711                         max_reclaim = 0;
4712                 else
4713                         max_reclaim -= nr_pages;
4714
4715                 wait_event(fs_info->async_submit_wait,
4716                            atomic_read(&fs_info->async_delalloc_pages) <=
4717                            (int)max_reclaim);
4718 skip_async:
4719                 spin_lock(&space_info->lock);
4720                 if (list_empty(&space_info->tickets) &&
4721                     list_empty(&space_info->priority_tickets)) {
4722                         spin_unlock(&space_info->lock);
4723                         break;
4724                 }
4725                 spin_unlock(&space_info->lock);
4726
4727                 loops++;
4728                 if (wait_ordered && !trans) {
4729                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4730                 } else {
4731                         time_left = schedule_timeout_killable(1);
4732                         if (time_left)
4733                                 break;
4734                 }
4735                 delalloc_bytes = percpu_counter_sum_positive(
4736                                                 &fs_info->delalloc_bytes);
4737         }
4738 }
4739
4740 struct reserve_ticket {
4741         u64 bytes;
4742         int error;
4743         struct list_head list;
4744         wait_queue_head_t wait;
4745 };
4746
4747 /**
4748  * maybe_commit_transaction - possibly commit the transaction if its ok to
4749  * @root - the root we're allocating for
4750  * @bytes - the number of bytes we want to reserve
4751  * @force - force the commit
4752  *
4753  * This will check to make sure that committing the transaction will actually
4754  * get us somewhere and then commit the transaction if it does.  Otherwise it
4755  * will return -ENOSPC.
4756  */
4757 static int may_commit_transaction(struct btrfs_fs_info *fs_info,
4758                                   struct btrfs_space_info *space_info)
4759 {
4760         struct reserve_ticket *ticket = NULL;
4761         struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
4762         struct btrfs_trans_handle *trans;
4763         u64 bytes;
4764
4765         trans = (struct btrfs_trans_handle *)current->journal_info;
4766         if (trans)
4767                 return -EAGAIN;
4768
4769         spin_lock(&space_info->lock);
4770         if (!list_empty(&space_info->priority_tickets))
4771                 ticket = list_first_entry(&space_info->priority_tickets,
4772                                           struct reserve_ticket, list);
4773         else if (!list_empty(&space_info->tickets))
4774                 ticket = list_first_entry(&space_info->tickets,
4775                                           struct reserve_ticket, list);
4776         bytes = (ticket) ? ticket->bytes : 0;
4777         spin_unlock(&space_info->lock);
4778
4779         if (!bytes)
4780                 return 0;
4781
4782         /* See if there is enough pinned space to make this reservation */
4783         if (__percpu_counter_compare(&space_info->total_bytes_pinned,
4784                                    bytes,
4785                                    BTRFS_TOTAL_BYTES_PINNED_BATCH) >= 0)
4786                 goto commit;
4787
4788         /*
4789          * See if there is some space in the delayed insertion reservation for
4790          * this reservation.
4791          */
4792         if (space_info != delayed_rsv->space_info)
4793                 return -ENOSPC;
4794
4795         spin_lock(&delayed_rsv->lock);
4796         if (delayed_rsv->size > bytes)
4797                 bytes = 0;
4798         else
4799                 bytes -= delayed_rsv->size;
4800         spin_unlock(&delayed_rsv->lock);
4801
4802         if (__percpu_counter_compare(&space_info->total_bytes_pinned,
4803                                    bytes,
4804                                    BTRFS_TOTAL_BYTES_PINNED_BATCH) < 0) {
4805                 return -ENOSPC;
4806         }
4807
4808 commit:
4809         trans = btrfs_join_transaction(fs_info->extent_root);
4810         if (IS_ERR(trans))
4811                 return -ENOSPC;
4812
4813         return btrfs_commit_transaction(trans);
4814 }
4815
4816 /*
4817  * Try to flush some data based on policy set by @state. This is only advisory
4818  * and may fail for various reasons. The caller is supposed to examine the
4819  * state of @space_info to detect the outcome.
4820  */
4821 static void flush_space(struct btrfs_fs_info *fs_info,
4822                        struct btrfs_space_info *space_info, u64 num_bytes,
4823                        int state)
4824 {
4825         struct btrfs_root *root = fs_info->extent_root;
4826         struct btrfs_trans_handle *trans;
4827         int nr;
4828         int ret = 0;
4829
4830         switch (state) {
4831         case FLUSH_DELAYED_ITEMS_NR:
4832         case FLUSH_DELAYED_ITEMS:
4833                 if (state == FLUSH_DELAYED_ITEMS_NR)
4834                         nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
4835                 else
4836                         nr = -1;
4837
4838                 trans = btrfs_join_transaction(root);
4839                 if (IS_ERR(trans)) {
4840                         ret = PTR_ERR(trans);
4841                         break;
4842                 }
4843                 ret = btrfs_run_delayed_items_nr(trans, nr);
4844                 btrfs_end_transaction(trans);
4845                 break;
4846         case FLUSH_DELALLOC:
4847         case FLUSH_DELALLOC_WAIT:
4848                 shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
4849                                 state == FLUSH_DELALLOC_WAIT);
4850                 break;
4851         case ALLOC_CHUNK:
4852                 trans = btrfs_join_transaction(root);
4853                 if (IS_ERR(trans)) {
4854                         ret = PTR_ERR(trans);
4855                         break;
4856                 }
4857                 ret = do_chunk_alloc(trans,
4858                                      btrfs_metadata_alloc_profile(fs_info),
4859                                      CHUNK_ALLOC_NO_FORCE);
4860                 btrfs_end_transaction(trans);
4861                 if (ret > 0 || ret == -ENOSPC)
4862                         ret = 0;
4863                 break;
4864         case COMMIT_TRANS:
4865                 ret = may_commit_transaction(fs_info, space_info);
4866                 break;
4867         default:
4868                 ret = -ENOSPC;
4869                 break;
4870         }
4871
4872         trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
4873                                 ret);
4874         return;
4875 }
4876
4877 static inline u64
4878 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
4879                                  struct btrfs_space_info *space_info,
4880                                  bool system_chunk)
4881 {
4882         struct reserve_ticket *ticket;
4883         u64 used;
4884         u64 expected;
4885         u64 to_reclaim = 0;
4886
4887         list_for_each_entry(ticket, &space_info->tickets, list)
4888                 to_reclaim += ticket->bytes;
4889         list_for_each_entry(ticket, &space_info->priority_tickets, list)
4890                 to_reclaim += ticket->bytes;
4891         if (to_reclaim)
4892                 return to_reclaim;
4893
4894         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4895         if (can_overcommit(fs_info, space_info, to_reclaim,
4896                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
4897                 return 0;
4898
4899         used = btrfs_space_info_used(space_info, true);
4900
4901         if (can_overcommit(fs_info, space_info, SZ_1M,
4902                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
4903                 expected = div_factor_fine(space_info->total_bytes, 95);
4904         else
4905                 expected = div_factor_fine(space_info->total_bytes, 90);
4906
4907         if (used > expected)
4908                 to_reclaim = used - expected;
4909         else
4910                 to_reclaim = 0;
4911         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4912                                      space_info->bytes_reserved);
4913         return to_reclaim;
4914 }
4915
4916 static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
4917                                         struct btrfs_space_info *space_info,
4918                                         u64 used, bool system_chunk)
4919 {
4920         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4921
4922         /* If we're just plain full then async reclaim just slows us down. */
4923         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4924                 return 0;
4925
4926         if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info,
4927                                               system_chunk))
4928                 return 0;
4929
4930         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4931                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4932 }
4933
4934 static void wake_all_tickets(struct list_head *head)
4935 {
4936         struct reserve_ticket *ticket;
4937
4938         while (!list_empty(head)) {
4939                 ticket = list_first_entry(head, struct reserve_ticket, list);
4940                 list_del_init(&ticket->list);
4941                 ticket->error = -ENOSPC;
4942                 wake_up(&ticket->wait);
4943         }
4944 }
4945
4946 /*
4947  * This is for normal flushers, we can wait all goddamned day if we want to.  We
4948  * will loop and continuously try to flush as long as we are making progress.
4949  * We count progress as clearing off tickets each time we have to loop.
4950  */
4951 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4952 {
4953         struct btrfs_fs_info *fs_info;
4954         struct btrfs_space_info *space_info;
4955         u64 to_reclaim;
4956         int flush_state;
4957         int commit_cycles = 0;
4958         u64 last_tickets_id;
4959
4960         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4961         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4962
4963         spin_lock(&space_info->lock);
4964         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
4965                                                       false);
4966         if (!to_reclaim) {
4967                 space_info->flush = 0;
4968                 spin_unlock(&space_info->lock);
4969                 return;
4970         }
4971         last_tickets_id = space_info->tickets_id;
4972         spin_unlock(&space_info->lock);
4973
4974         flush_state = FLUSH_DELAYED_ITEMS_NR;
4975         do {
4976                 flush_space(fs_info, space_info, to_reclaim, flush_state);
4977                 spin_lock(&space_info->lock);
4978                 if (list_empty(&space_info->tickets)) {
4979                         space_info->flush = 0;
4980                         spin_unlock(&space_info->lock);
4981                         return;
4982                 }
4983                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
4984                                                               space_info,
4985                                                               false);
4986                 if (last_tickets_id == space_info->tickets_id) {
4987                         flush_state++;
4988                 } else {
4989                         last_tickets_id = space_info->tickets_id;
4990                         flush_state = FLUSH_DELAYED_ITEMS_NR;
4991                         if (commit_cycles)
4992                                 commit_cycles--;
4993                 }
4994
4995                 if (flush_state > COMMIT_TRANS) {
4996                         commit_cycles++;
4997                         if (commit_cycles > 2) {
4998                                 wake_all_tickets(&space_info->tickets);
4999                                 space_info->flush = 0;
5000                         } else {
5001                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5002                         }
5003                 }
5004                 spin_unlock(&space_info->lock);
5005         } while (flush_state <= COMMIT_TRANS);
5006 }
5007
5008 void btrfs_init_async_reclaim_work(struct work_struct *work)
5009 {
5010         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5011 }
5012
5013 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5014                                             struct btrfs_space_info *space_info,
5015                                             struct reserve_ticket *ticket)
5016 {
5017         u64 to_reclaim;
5018         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5019
5020         spin_lock(&space_info->lock);
5021         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5022                                                       false);
5023         if (!to_reclaim) {
5024                 spin_unlock(&space_info->lock);
5025                 return;
5026         }
5027         spin_unlock(&space_info->lock);
5028
5029         do {
5030                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5031                 flush_state++;
5032                 spin_lock(&space_info->lock);
5033                 if (ticket->bytes == 0) {
5034                         spin_unlock(&space_info->lock);
5035                         return;
5036                 }
5037                 spin_unlock(&space_info->lock);
5038
5039                 /*
5040                  * Priority flushers can't wait on delalloc without
5041                  * deadlocking.
5042                  */
5043                 if (flush_state == FLUSH_DELALLOC ||
5044                     flush_state == FLUSH_DELALLOC_WAIT)
5045                         flush_state = ALLOC_CHUNK;
5046         } while (flush_state < COMMIT_TRANS);
5047 }
5048
5049 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5050                                struct btrfs_space_info *space_info,
5051                                struct reserve_ticket *ticket, u64 orig_bytes)
5052
5053 {
5054         DEFINE_WAIT(wait);
5055         int ret = 0;
5056
5057         spin_lock(&space_info->lock);
5058         while (ticket->bytes > 0 && ticket->error == 0) {
5059                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5060                 if (ret) {
5061                         ret = -EINTR;
5062                         break;
5063                 }
5064                 spin_unlock(&space_info->lock);
5065
5066                 schedule();
5067
5068                 finish_wait(&ticket->wait, &wait);
5069                 spin_lock(&space_info->lock);
5070         }
5071         if (!ret)
5072                 ret = ticket->error;
5073         if (!list_empty(&ticket->list))
5074                 list_del_init(&ticket->list);
5075         if (ticket->bytes && ticket->bytes < orig_bytes) {
5076                 u64 num_bytes = orig_bytes - ticket->bytes;
5077                 space_info->bytes_may_use -= num_bytes;
5078                 trace_btrfs_space_reservation(fs_info, "space_info",
5079                                               space_info->flags, num_bytes, 0);
5080         }
5081         spin_unlock(&space_info->lock);
5082
5083         return ret;
5084 }
5085
5086 /**
5087  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5088  * @root - the root we're allocating for
5089  * @space_info - the space info we want to allocate from
5090  * @orig_bytes - the number of bytes we want
5091  * @flush - whether or not we can flush to make our reservation
5092  *
5093  * This will reserve orig_bytes number of bytes from the space info associated
5094  * with the block_rsv.  If there is not enough space it will make an attempt to
5095  * flush out space to make room.  It will do this by flushing delalloc if
5096  * possible or committing the transaction.  If flush is 0 then no attempts to
5097  * regain reservations will be made and this will fail if there is not enough
5098  * space already.
5099  */
5100 static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
5101                                     struct btrfs_space_info *space_info,
5102                                     u64 orig_bytes,
5103                                     enum btrfs_reserve_flush_enum flush,
5104                                     bool system_chunk)
5105 {
5106         struct reserve_ticket ticket;
5107         u64 used;
5108         int ret = 0;
5109
5110         ASSERT(orig_bytes);
5111         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5112
5113         spin_lock(&space_info->lock);
5114         ret = -ENOSPC;
5115         used = btrfs_space_info_used(space_info, true);
5116
5117         /*
5118          * If we have enough space then hooray, make our reservation and carry
5119          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5120          * If not things get more complicated.
5121          */
5122         if (used + orig_bytes <= space_info->total_bytes) {
5123                 space_info->bytes_may_use += orig_bytes;
5124                 trace_btrfs_space_reservation(fs_info, "space_info",
5125                                               space_info->flags, orig_bytes, 1);
5126                 ret = 0;
5127         } else if (can_overcommit(fs_info, space_info, orig_bytes, flush,
5128                                   system_chunk)) {
5129                 space_info->bytes_may_use += orig_bytes;
5130                 trace_btrfs_space_reservation(fs_info, "space_info",
5131                                               space_info->flags, orig_bytes, 1);
5132                 ret = 0;
5133         }
5134
5135         /*
5136          * If we couldn't make a reservation then setup our reservation ticket
5137          * and kick the async worker if it's not already running.
5138          *
5139          * If we are a priority flusher then we just need to add our ticket to
5140          * the list and we will do our own flushing further down.
5141          */
5142         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5143                 ticket.bytes = orig_bytes;
5144                 ticket.error = 0;
5145                 init_waitqueue_head(&ticket.wait);
5146                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5147                         list_add_tail(&ticket.list, &space_info->tickets);
5148                         if (!space_info->flush) {
5149                                 space_info->flush = 1;
5150                                 trace_btrfs_trigger_flush(fs_info,
5151                                                           space_info->flags,
5152                                                           orig_bytes, flush,
5153                                                           "enospc");
5154                                 queue_work(system_unbound_wq,
5155                                            &fs_info->async_reclaim_work);
5156                         }
5157                 } else {
5158                         list_add_tail(&ticket.list,
5159                                       &space_info->priority_tickets);
5160                 }
5161         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5162                 used += orig_bytes;
5163                 /*
5164                  * We will do the space reservation dance during log replay,
5165                  * which means we won't have fs_info->fs_root set, so don't do
5166                  * the async reclaim as we will panic.
5167                  */
5168                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
5169                     need_do_async_reclaim(fs_info, space_info,
5170                                           used, system_chunk) &&
5171                     !work_busy(&fs_info->async_reclaim_work)) {
5172                         trace_btrfs_trigger_flush(fs_info, space_info->flags,
5173                                                   orig_bytes, flush, "preempt");
5174                         queue_work(system_unbound_wq,
5175                                    &fs_info->async_reclaim_work);
5176                 }
5177         }
5178         spin_unlock(&space_info->lock);
5179         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5180                 return ret;
5181
5182         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5183                 return wait_reserve_ticket(fs_info, space_info, &ticket,
5184                                            orig_bytes);
5185
5186         ret = 0;
5187         priority_reclaim_metadata_space(fs_info, space_info, &ticket);
5188         spin_lock(&space_info->lock);
5189         if (ticket.bytes) {
5190                 if (ticket.bytes < orig_bytes) {
5191                         u64 num_bytes = orig_bytes - ticket.bytes;
5192                         space_info->bytes_may_use -= num_bytes;
5193                         trace_btrfs_space_reservation(fs_info, "space_info",
5194                                                       space_info->flags,
5195                                                       num_bytes, 0);
5196
5197                 }
5198                 list_del_init(&ticket.list);
5199                 ret = -ENOSPC;
5200         }
5201         spin_unlock(&space_info->lock);
5202         ASSERT(list_empty(&ticket.list));
5203         return ret;
5204 }
5205
5206 /**
5207  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5208  * @root - the root we're allocating for
5209  * @block_rsv - the block_rsv we're allocating for
5210  * @orig_bytes - the number of bytes we want
5211  * @flush - whether or not we can flush to make our reservation
5212  *
5213  * This will reserve orgi_bytes number of bytes from the space info associated
5214  * with the block_rsv.  If there is not enough space it will make an attempt to
5215  * flush out space to make room.  It will do this by flushing delalloc if
5216  * possible or committing the transaction.  If flush is 0 then no attempts to
5217  * regain reservations will be made and this will fail if there is not enough
5218  * space already.
5219  */
5220 static int reserve_metadata_bytes(struct btrfs_root *root,
5221                                   struct btrfs_block_rsv *block_rsv,
5222                                   u64 orig_bytes,
5223                                   enum btrfs_reserve_flush_enum flush)
5224 {
5225         struct btrfs_fs_info *fs_info = root->fs_info;
5226         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5227         int ret;
5228         bool system_chunk = (root == fs_info->chunk_root);
5229
5230         ret = __reserve_metadata_bytes(fs_info, block_rsv->space_info,
5231                                        orig_bytes, flush, system_chunk);
5232         if (ret == -ENOSPC &&
5233             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5234                 if (block_rsv != global_rsv &&
5235                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5236                         ret = 0;
5237         }
5238         if (ret == -ENOSPC) {
5239                 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
5240                                               block_rsv->space_info->flags,
5241                                               orig_bytes, 1);
5242
5243                 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
5244                         dump_space_info(fs_info, block_rsv->space_info,
5245                                         orig_bytes, 0);
5246         }
5247         return ret;
5248 }
5249
5250 static struct btrfs_block_rsv *get_block_rsv(
5251                                         const struct btrfs_trans_handle *trans,
5252                                         const struct btrfs_root *root)
5253 {
5254         struct btrfs_fs_info *fs_info = root->fs_info;
5255         struct btrfs_block_rsv *block_rsv = NULL;
5256
5257         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5258             (root == fs_info->csum_root && trans->adding_csums) ||
5259             (root == fs_info->uuid_root))
5260                 block_rsv = trans->block_rsv;
5261
5262         if (!block_rsv)
5263                 block_rsv = root->block_rsv;
5264
5265         if (!block_rsv)
5266                 block_rsv = &fs_info->empty_block_rsv;
5267
5268         return block_rsv;
5269 }
5270
5271 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5272                                u64 num_bytes)
5273 {
5274         int ret = -ENOSPC;
5275         spin_lock(&block_rsv->lock);
5276         if (block_rsv->reserved >= num_bytes) {
5277                 block_rsv->reserved -= num_bytes;
5278                 if (block_rsv->reserved < block_rsv->size)
5279                         block_rsv->full = 0;
5280                 ret = 0;
5281         }
5282         spin_unlock(&block_rsv->lock);
5283         return ret;
5284 }
5285
5286 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5287                                 u64 num_bytes, bool update_size)
5288 {
5289         spin_lock(&block_rsv->lock);
5290         block_rsv->reserved += num_bytes;
5291         if (update_size)
5292                 block_rsv->size += num_bytes;
5293         else if (block_rsv->reserved >= block_rsv->size)
5294                 block_rsv->full = 1;
5295         spin_unlock(&block_rsv->lock);
5296 }
5297
5298 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5299                              struct btrfs_block_rsv *dest, u64 num_bytes,
5300                              int min_factor)
5301 {
5302         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5303         u64 min_bytes;
5304
5305         if (global_rsv->space_info != dest->space_info)
5306                 return -ENOSPC;
5307
5308         spin_lock(&global_rsv->lock);
5309         min_bytes = div_factor(global_rsv->size, min_factor);
5310         if (global_rsv->reserved < min_bytes + num_bytes) {
5311                 spin_unlock(&global_rsv->lock);
5312                 return -ENOSPC;
5313         }
5314         global_rsv->reserved -= num_bytes;
5315         if (global_rsv->reserved < global_rsv->size)
5316                 global_rsv->full = 0;
5317         spin_unlock(&global_rsv->lock);
5318
5319         block_rsv_add_bytes(dest, num_bytes, true);
5320         return 0;
5321 }
5322
5323 /*
5324  * This is for space we already have accounted in space_info->bytes_may_use, so
5325  * basically when we're returning space from block_rsv's.
5326  */
5327 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5328                                      struct btrfs_space_info *space_info,
5329                                      u64 num_bytes)
5330 {
5331         struct reserve_ticket *ticket;
5332         struct list_head *head;
5333         u64 used;
5334         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5335         bool check_overcommit = false;
5336
5337         spin_lock(&space_info->lock);
5338         head = &space_info->priority_tickets;
5339
5340         /*
5341          * If we are over our limit then we need to check and see if we can
5342          * overcommit, and if we can't then we just need to free up our space
5343          * and not satisfy any requests.
5344          */
5345         used = btrfs_space_info_used(space_info, true);
5346         if (used - num_bytes >= space_info->total_bytes)
5347                 check_overcommit = true;
5348 again:
5349         while (!list_empty(head) && num_bytes) {
5350                 ticket = list_first_entry(head, struct reserve_ticket,
5351                                           list);
5352                 /*
5353                  * We use 0 bytes because this space is already reserved, so
5354                  * adding the ticket space would be a double count.
5355                  */
5356                 if (check_overcommit &&
5357                     !can_overcommit(fs_info, space_info, 0, flush, false))
5358                         break;
5359                 if (num_bytes >= ticket->bytes) {
5360                         list_del_init(&ticket->list);
5361                         num_bytes -= ticket->bytes;
5362                         ticket->bytes = 0;
5363                         space_info->tickets_id++;
5364                         wake_up(&ticket->wait);
5365                 } else {
5366                         ticket->bytes -= num_bytes;
5367                         num_bytes = 0;
5368                 }
5369         }
5370
5371         if (num_bytes && head == &space_info->priority_tickets) {
5372                 head = &space_info->tickets;
5373                 flush = BTRFS_RESERVE_FLUSH_ALL;
5374                 goto again;
5375         }
5376         space_info->bytes_may_use -= num_bytes;
5377         trace_btrfs_space_reservation(fs_info, "space_info",
5378                                       space_info->flags, num_bytes, 0);
5379         spin_unlock(&space_info->lock);
5380 }
5381
5382 /*
5383  * This is for newly allocated space that isn't accounted in
5384  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5385  * we use this helper.
5386  */
5387 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5388                                      struct btrfs_space_info *space_info,
5389                                      u64 num_bytes)
5390 {
5391         struct reserve_ticket *ticket;
5392         struct list_head *head = &space_info->priority_tickets;
5393
5394 again:
5395         while (!list_empty(head) && num_bytes) {
5396                 ticket = list_first_entry(head, struct reserve_ticket,
5397                                           list);
5398                 if (num_bytes >= ticket->bytes) {
5399                         trace_btrfs_space_reservation(fs_info, "space_info",
5400                                                       space_info->flags,
5401                                                       ticket->bytes, 1);
5402                         list_del_init(&ticket->list);
5403                         num_bytes -= ticket->bytes;
5404                         space_info->bytes_may_use += ticket->bytes;
5405                         ticket->bytes = 0;
5406                         space_info->tickets_id++;
5407                         wake_up(&ticket->wait);
5408                 } else {
5409                         trace_btrfs_space_reservation(fs_info, "space_info",
5410                                                       space_info->flags,
5411                                                       num_bytes, 1);
5412                         space_info->bytes_may_use += num_bytes;
5413                         ticket->bytes -= num_bytes;
5414                         num_bytes = 0;
5415                 }
5416         }
5417
5418         if (num_bytes && head == &space_info->priority_tickets) {
5419                 head = &space_info->tickets;
5420                 goto again;
5421         }
5422 }
5423
5424 static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5425                                     struct btrfs_block_rsv *block_rsv,
5426                                     struct btrfs_block_rsv *dest, u64 num_bytes,
5427                                     u64 *qgroup_to_release_ret)
5428 {
5429         struct btrfs_space_info *space_info = block_rsv->space_info;
5430         u64 qgroup_to_release = 0;
5431         u64 ret;
5432
5433         spin_lock(&block_rsv->lock);
5434         if (num_bytes == (u64)-1) {
5435                 num_bytes = block_rsv->size;
5436                 qgroup_to_release = block_rsv->qgroup_rsv_size;
5437         }
5438         block_rsv->size -= num_bytes;
5439         if (block_rsv->reserved >= block_rsv->size) {
5440                 num_bytes = block_rsv->reserved - block_rsv->size;
5441                 block_rsv->reserved = block_rsv->size;
5442                 block_rsv->full = 1;
5443         } else {
5444                 num_bytes = 0;
5445         }
5446         if (block_rsv->qgroup_rsv_reserved >= block_rsv->qgroup_rsv_size) {
5447                 qgroup_to_release = block_rsv->qgroup_rsv_reserved -
5448                                     block_rsv->qgroup_rsv_size;
5449                 block_rsv->qgroup_rsv_reserved = block_rsv->qgroup_rsv_size;
5450         } else {
5451                 qgroup_to_release = 0;
5452         }
5453         spin_unlock(&block_rsv->lock);
5454
5455         ret = num_bytes;
5456         if (num_bytes > 0) {
5457                 if (dest) {
5458                         spin_lock(&dest->lock);
5459                         if (!dest->full) {
5460                                 u64 bytes_to_add;
5461
5462                                 bytes_to_add = dest->size - dest->reserved;
5463                                 bytes_to_add = min(num_bytes, bytes_to_add);
5464                                 dest->reserved += bytes_to_add;
5465                                 if (dest->reserved >= dest->size)
5466                                         dest->full = 1;
5467                                 num_bytes -= bytes_to_add;
5468                         }
5469                         spin_unlock(&dest->lock);
5470                 }
5471                 if (num_bytes)
5472                         space_info_add_old_bytes(fs_info, space_info,
5473                                                  num_bytes);
5474         }
5475         if (qgroup_to_release_ret)
5476                 *qgroup_to_release_ret = qgroup_to_release;
5477         return ret;
5478 }
5479
5480 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5481                             struct btrfs_block_rsv *dst, u64 num_bytes,
5482                             bool update_size)
5483 {
5484         int ret;
5485
5486         ret = block_rsv_use_bytes(src, num_bytes);
5487         if (ret)
5488                 return ret;
5489
5490         block_rsv_add_bytes(dst, num_bytes, update_size);
5491         return 0;
5492 }
5493
5494 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5495 {
5496         memset(rsv, 0, sizeof(*rsv));
5497         spin_lock_init(&rsv->lock);
5498         rsv->type = type;
5499 }
5500
5501 void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,
5502                                    struct btrfs_block_rsv *rsv,
5503                                    unsigned short type)
5504 {
5505         btrfs_init_block_rsv(rsv, type);
5506         rsv->space_info = __find_space_info(fs_info,
5507                                             BTRFS_BLOCK_GROUP_METADATA);
5508 }
5509
5510 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
5511                                               unsigned short type)
5512 {
5513         struct btrfs_block_rsv *block_rsv;
5514
5515         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5516         if (!block_rsv)
5517                 return NULL;
5518
5519         btrfs_init_metadata_block_rsv(fs_info, block_rsv, type);
5520         return block_rsv;
5521 }
5522
5523 void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
5524                           struct btrfs_block_rsv *rsv)
5525 {
5526         if (!rsv)
5527                 return;
5528         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5529         kfree(rsv);
5530 }
5531
5532 int btrfs_block_rsv_add(struct btrfs_root *root,
5533                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5534                         enum btrfs_reserve_flush_enum flush)
5535 {
5536         int ret;
5537
5538         if (num_bytes == 0)
5539                 return 0;
5540
5541         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5542         if (!ret)
5543                 block_rsv_add_bytes(block_rsv, num_bytes, true);
5544
5545         return ret;
5546 }
5547
5548 int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
5549 {
5550         u64 num_bytes = 0;
5551         int ret = -ENOSPC;
5552
5553         if (!block_rsv)
5554                 return 0;
5555
5556         spin_lock(&block_rsv->lock);
5557         num_bytes = div_factor(block_rsv->size, min_factor);
5558         if (block_rsv->reserved >= num_bytes)
5559                 ret = 0;
5560         spin_unlock(&block_rsv->lock);
5561
5562         return ret;
5563 }
5564
5565 int btrfs_block_rsv_refill(struct btrfs_root *root,
5566                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5567                            enum btrfs_reserve_flush_enum flush)
5568 {
5569         u64 num_bytes = 0;
5570         int ret = -ENOSPC;
5571
5572         if (!block_rsv)
5573                 return 0;
5574
5575         spin_lock(&block_rsv->lock);
5576         num_bytes = min_reserved;
5577         if (block_rsv->reserved >= num_bytes)
5578                 ret = 0;
5579         else
5580                 num_bytes -= block_rsv->reserved;
5581         spin_unlock(&block_rsv->lock);
5582
5583         if (!ret)
5584                 return 0;
5585
5586         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5587         if (!ret) {
5588                 block_rsv_add_bytes(block_rsv, num_bytes, false);
5589                 return 0;
5590         }
5591
5592         return ret;
5593 }
5594
5595 /**
5596  * btrfs_inode_rsv_refill - refill the inode block rsv.
5597  * @inode - the inode we are refilling.
5598  * @flush - the flusing restriction.
5599  *
5600  * Essentially the same as btrfs_block_rsv_refill, except it uses the
5601  * block_rsv->size as the minimum size.  We'll either refill the missing amount
5602  * or return if we already have enough space.  This will also handle the resreve
5603  * tracepoint for the reserved amount.
5604  */
5605 static int btrfs_inode_rsv_refill(struct btrfs_inode *inode,
5606                                   enum btrfs_reserve_flush_enum flush)
5607 {
5608         struct btrfs_root *root = inode->root;
5609         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5610         u64 num_bytes = 0;
5611         u64 qgroup_num_bytes = 0;
5612         int ret = -ENOSPC;
5613
5614         spin_lock(&block_rsv->lock);
5615         if (block_rsv->reserved < block_rsv->size)
5616                 num_bytes = block_rsv->size - block_rsv->reserved;
5617         if (block_rsv->qgroup_rsv_reserved < block_rsv->qgroup_rsv_size)
5618                 qgroup_num_bytes = block_rsv->qgroup_rsv_size -
5619                                    block_rsv->qgroup_rsv_reserved;
5620         spin_unlock(&block_rsv->lock);
5621
5622         if (num_bytes == 0)
5623                 return 0;
5624
5625         ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_num_bytes, true);
5626         if (ret)
5627                 return ret;
5628         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5629         if (!ret) {
5630                 block_rsv_add_bytes(block_rsv, num_bytes, false);
5631                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5632                                               btrfs_ino(inode), num_bytes, 1);
5633
5634                 /* Don't forget to increase qgroup_rsv_reserved */
5635                 spin_lock(&block_rsv->lock);
5636                 block_rsv->qgroup_rsv_reserved += qgroup_num_bytes;
5637                 spin_unlock(&block_rsv->lock);
5638         } else
5639                 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
5640         return ret;
5641 }
5642
5643 /**
5644  * btrfs_inode_rsv_release - release any excessive reservation.
5645  * @inode - the inode we need to release from.
5646  * @qgroup_free - free or convert qgroup meta.
5647  *   Unlike normal operation, qgroup meta reservation needs to know if we are
5648  *   freeing qgroup reservation or just converting it into per-trans.  Normally
5649  *   @qgroup_free is true for error handling, and false for normal release.
5650  *
5651  * This is the same as btrfs_block_rsv_release, except that it handles the
5652  * tracepoint for the reservation.
5653  */
5654 static void btrfs_inode_rsv_release(struct btrfs_inode *inode, bool qgroup_free)
5655 {
5656         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5657         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5658         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5659         u64 released = 0;
5660         u64 qgroup_to_release = 0;
5661
5662         /*
5663          * Since we statically set the block_rsv->size we just want to say we
5664          * are releasing 0 bytes, and then we'll just get the reservation over
5665          * the size free'd.
5666          */
5667         released = block_rsv_release_bytes(fs_info, block_rsv, global_rsv, 0,
5668                                            &qgroup_to_release);
5669         if (released > 0)
5670                 trace_btrfs_space_reservation(fs_info, "delalloc",
5671                                               btrfs_ino(inode), released, 0);
5672         if (qgroup_free)
5673                 btrfs_qgroup_free_meta_prealloc(inode->root, qgroup_to_release);
5674         else
5675                 btrfs_qgroup_convert_reserved_meta(inode->root,
5676                                                    qgroup_to_release);
5677 }
5678
5679 void btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
5680                              struct btrfs_block_rsv *block_rsv,
5681                              u64 num_bytes)
5682 {
5683         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5684
5685         if (global_rsv == block_rsv ||
5686             block_rsv->space_info != global_rsv->space_info)
5687                 global_rsv = NULL;
5688         block_rsv_release_bytes(fs_info, block_rsv, global_rsv, num_bytes, NULL);
5689 }
5690
5691 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5692 {
5693         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5694         struct btrfs_space_info *sinfo = block_rsv->space_info;
5695         u64 num_bytes;
5696
5697         /*
5698          * The global block rsv is based on the size of the extent tree, the
5699          * checksum tree and the root tree.  If the fs is empty we want to set
5700          * it to a minimal amount for safety.
5701          */
5702         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5703                 btrfs_root_used(&fs_info->csum_root->root_item) +
5704                 btrfs_root_used(&fs_info->tree_root->root_item);
5705         num_bytes = max_t(u64, num_bytes, SZ_16M);
5706
5707         spin_lock(&sinfo->lock);
5708         spin_lock(&block_rsv->lock);
5709
5710         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5711
5712         if (block_rsv->reserved < block_rsv->size) {
5713                 num_bytes = btrfs_space_info_used(sinfo, true);
5714                 if (sinfo->total_bytes > num_bytes) {
5715                         num_bytes = sinfo->total_bytes - num_bytes;
5716                         num_bytes = min(num_bytes,
5717                                         block_rsv->size - block_rsv->reserved);
5718                         block_rsv->reserved += num_bytes;
5719                         sinfo->bytes_may_use += num_bytes;
5720                         trace_btrfs_space_reservation(fs_info, "space_info",
5721                                                       sinfo->flags, num_bytes,
5722                                                       1);
5723                 }
5724         } else if (block_rsv->reserved > block_rsv->size) {
5725                 num_bytes = block_rsv->reserved - block_rsv->size;
5726                 sinfo->bytes_may_use -= num_bytes;
5727                 trace_btrfs_space_reservation(fs_info, "space_info",
5728                                       sinfo->flags, num_bytes, 0);
5729                 block_rsv->reserved = block_rsv->size;
5730         }
5731
5732         if (block_rsv->reserved == block_rsv->size)
5733                 block_rsv->full = 1;
5734         else
5735                 block_rsv->full = 0;
5736
5737         spin_unlock(&block_rsv->lock);
5738         spin_unlock(&sinfo->lock);
5739 }
5740
5741 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5742 {
5743         struct btrfs_space_info *space_info;
5744
5745         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5746         fs_info->chunk_block_rsv.space_info = space_info;
5747
5748         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5749         fs_info->global_block_rsv.space_info = space_info;
5750         fs_info->trans_block_rsv.space_info = space_info;
5751         fs_info->empty_block_rsv.space_info = space_info;
5752         fs_info->delayed_block_rsv.space_info = space_info;
5753
5754         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5755         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5756         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5757         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5758         if (fs_info->quota_root)
5759                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5760         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5761
5762         update_global_block_rsv(fs_info);
5763 }
5764
5765 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5766 {
5767         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5768                                 (u64)-1, NULL);
5769         WARN_ON(fs_info->trans_block_rsv.size > 0);
5770         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5771         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5772         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5773         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5774         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5775 }
5776
5777
5778 /*
5779  * To be called after all the new block groups attached to the transaction
5780  * handle have been created (btrfs_create_pending_block_groups()).
5781  */
5782 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5783 {
5784         struct btrfs_fs_info *fs_info = trans->fs_info;
5785
5786         if (!trans->chunk_bytes_reserved)
5787                 return;
5788
5789         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5790
5791         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5792                                 trans->chunk_bytes_reserved, NULL);
5793         trans->chunk_bytes_reserved = 0;
5794 }
5795
5796 /*
5797  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5798  * root: the root of the parent directory
5799  * rsv: block reservation
5800  * items: the number of items that we need do reservation
5801  * use_global_rsv: allow fallback to the global block reservation
5802  *
5803  * This function is used to reserve the space for snapshot/subvolume
5804  * creation and deletion. Those operations are different with the
5805  * common file/directory operations, they change two fs/file trees
5806  * and root tree, the number of items that the qgroup reserves is
5807  * different with the free space reservation. So we can not use
5808  * the space reservation mechanism in start_transaction().
5809  */
5810 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5811                                      struct btrfs_block_rsv *rsv, int items,
5812                                      bool use_global_rsv)
5813 {
5814         u64 qgroup_num_bytes = 0;
5815         u64 num_bytes;
5816         int ret;
5817         struct btrfs_fs_info *fs_info = root->fs_info;
5818         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5819
5820         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5821                 /* One for parent inode, two for dir entries */
5822                 qgroup_num_bytes = 3 * fs_info->nodesize;
5823                 ret = btrfs_qgroup_reserve_meta_prealloc(root,
5824                                 qgroup_num_bytes, true);
5825                 if (ret)
5826                         return ret;
5827         }
5828
5829         num_bytes = btrfs_calc_trans_metadata_size(fs_info, items);
5830         rsv->space_info = __find_space_info(fs_info,
5831                                             BTRFS_BLOCK_GROUP_METADATA);
5832         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5833                                   BTRFS_RESERVE_FLUSH_ALL);
5834
5835         if (ret == -ENOSPC && use_global_rsv)
5836                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true);
5837
5838         if (ret && qgroup_num_bytes)
5839                 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
5840
5841         return ret;
5842 }
5843
5844 void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
5845                                       struct btrfs_block_rsv *rsv)
5846 {
5847         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5848 }
5849
5850 static void btrfs_calculate_inode_block_rsv_size(struct btrfs_fs_info *fs_info,
5851                                                  struct btrfs_inode *inode)
5852 {
5853         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5854         u64 reserve_size = 0;
5855         u64 qgroup_rsv_size = 0;
5856         u64 csum_leaves;
5857         unsigned outstanding_extents;
5858
5859         lockdep_assert_held(&inode->lock);
5860         outstanding_extents = inode->outstanding_extents;
5861         if (outstanding_extents)
5862                 reserve_size = btrfs_calc_trans_metadata_size(fs_info,
5863                                                 outstanding_extents + 1);
5864         csum_leaves = btrfs_csum_bytes_to_leaves(fs_info,
5865                                                  inode->csum_bytes);
5866         reserve_size += btrfs_calc_trans_metadata_size(fs_info,
5867                                                        csum_leaves);
5868         /*
5869          * For qgroup rsv, the calculation is very simple:
5870          * account one nodesize for each outstanding extent
5871          *
5872          * This is overestimating in most cases.
5873          */
5874         qgroup_rsv_size = outstanding_extents * fs_info->nodesize;
5875
5876         spin_lock(&block_rsv->lock);
5877         block_rsv->size = reserve_size;
5878         block_rsv->qgroup_rsv_size = qgroup_rsv_size;
5879         spin_unlock(&block_rsv->lock);
5880 }
5881
5882 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
5883 {
5884         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5885         unsigned nr_extents;
5886         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5887         int ret = 0;
5888         bool delalloc_lock = true;
5889
5890         /* If we are a free space inode we need to not flush since we will be in
5891          * the middle of a transaction commit.  We also don't need the delalloc
5892          * mutex since we won't race with anybody.  We need this mostly to make
5893          * lockdep shut its filthy mouth.
5894          *
5895          * If we have a transaction open (can happen if we call truncate_block
5896          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5897          */
5898         if (btrfs_is_free_space_inode(inode)) {
5899                 flush = BTRFS_RESERVE_NO_FLUSH;
5900                 delalloc_lock = false;
5901         } else {
5902                 if (current->journal_info)
5903                         flush = BTRFS_RESERVE_FLUSH_LIMIT;
5904
5905                 if (btrfs_transaction_in_commit(fs_info))
5906                         schedule_timeout(1);
5907         }
5908
5909         if (delalloc_lock)
5910                 mutex_lock(&inode->delalloc_mutex);
5911
5912         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
5913
5914         /* Add our new extents and calculate the new rsv size. */
5915         spin_lock(&inode->lock);
5916         nr_extents = count_max_extents(num_bytes);
5917         btrfs_mod_outstanding_extents(inode, nr_extents);
5918         inode->csum_bytes += num_bytes;
5919         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5920         spin_unlock(&inode->lock);
5921
5922         ret = btrfs_inode_rsv_refill(inode, flush);
5923         if (unlikely(ret))
5924                 goto out_fail;
5925
5926         if (delalloc_lock)
5927                 mutex_unlock(&inode->delalloc_mutex);
5928         return 0;
5929
5930 out_fail:
5931         spin_lock(&inode->lock);
5932         nr_extents = count_max_extents(num_bytes);
5933         btrfs_mod_outstanding_extents(inode, -nr_extents);
5934         inode->csum_bytes -= num_bytes;
5935         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5936         spin_unlock(&inode->lock);
5937
5938         btrfs_inode_rsv_release(inode, true);
5939         if (delalloc_lock)
5940                 mutex_unlock(&inode->delalloc_mutex);
5941         return ret;
5942 }
5943
5944 /**
5945  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5946  * @inode: the inode to release the reservation for.
5947  * @num_bytes: the number of bytes we are releasing.
5948  * @qgroup_free: free qgroup reservation or convert it to per-trans reservation
5949  *
5950  * This will release the metadata reservation for an inode.  This can be called
5951  * once we complete IO for a given set of bytes to release their metadata
5952  * reservations, or on error for the same reason.
5953  */
5954 void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes,
5955                                      bool qgroup_free)
5956 {
5957         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5958
5959         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
5960         spin_lock(&inode->lock);
5961         inode->csum_bytes -= num_bytes;
5962         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5963         spin_unlock(&inode->lock);
5964
5965         if (btrfs_is_testing(fs_info))
5966                 return;
5967
5968         btrfs_inode_rsv_release(inode, qgroup_free);
5969 }
5970
5971 /**
5972  * btrfs_delalloc_release_extents - release our outstanding_extents
5973  * @inode: the inode to balance the reservation for.
5974  * @num_bytes: the number of bytes we originally reserved with
5975  * @qgroup_free: do we need to free qgroup meta reservation or convert them.
5976  *
5977  * When we reserve space we increase outstanding_extents for the extents we may
5978  * add.  Once we've set the range as delalloc or created our ordered extents we
5979  * have outstanding_extents to track the real usage, so we use this to free our
5980  * temporarily tracked outstanding_extents.  This _must_ be used in conjunction
5981  * with btrfs_delalloc_reserve_metadata.
5982  */
5983 void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes,
5984                                     bool qgroup_free)
5985 {
5986         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5987         unsigned num_extents;
5988
5989         spin_lock(&inode->lock);
5990         num_extents = count_max_extents(num_bytes);
5991         btrfs_mod_outstanding_extents(inode, -num_extents);
5992         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5993         spin_unlock(&inode->lock);
5994
5995         if (btrfs_is_testing(fs_info))
5996                 return;
5997
5998         btrfs_inode_rsv_release(inode, qgroup_free);
5999 }
6000
6001 /**
6002  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6003  * delalloc
6004  * @inode: inode we're writing to
6005  * @start: start range we are writing to
6006  * @len: how long the range we are writing to
6007  * @reserved: mandatory parameter, record actually reserved qgroup ranges of
6008  *            current reservation.
6009  *
6010  * This will do the following things
6011  *
6012  * o reserve space in data space info for num bytes
6013  *   and reserve precious corresponding qgroup space
6014  *   (Done in check_data_free_space)
6015  *
6016  * o reserve space for metadata space, based on the number of outstanding
6017  *   extents and how much csums will be needed
6018  *   also reserve metadata space in a per root over-reserve method.
6019  * o add to the inodes->delalloc_bytes
6020  * o add it to the fs_info's delalloc inodes list.
6021  *   (Above 3 all done in delalloc_reserve_metadata)
6022  *
6023  * Return 0 for success
6024  * Return <0 for error(-ENOSPC or -EQUOT)
6025  */
6026 int btrfs_delalloc_reserve_space(struct inode *inode,
6027                         struct extent_changeset **reserved, u64 start, u64 len)
6028 {
6029         int ret;
6030
6031         ret = btrfs_check_data_free_space(inode, reserved, start, len);
6032         if (ret < 0)
6033                 return ret;
6034         ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);
6035         if (ret < 0)
6036                 btrfs_free_reserved_data_space(inode, *reserved, start, len);
6037         return ret;
6038 }
6039
6040 /**
6041  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6042  * @inode: inode we're releasing space for
6043  * @start: start position of the space already reserved
6044  * @len: the len of the space already reserved
6045  * @release_bytes: the len of the space we consumed or didn't use
6046  *
6047  * This function will release the metadata space that was not used and will
6048  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6049  * list if there are no delalloc bytes left.
6050  * Also it will handle the qgroup reserved space.
6051  */
6052 void btrfs_delalloc_release_space(struct inode *inode,
6053                                   struct extent_changeset *reserved,
6054                                   u64 start, u64 len, bool qgroup_free)
6055 {
6056         btrfs_delalloc_release_metadata(BTRFS_I(inode), len, qgroup_free);
6057         btrfs_free_reserved_data_space(inode, reserved, start, len);
6058 }
6059
6060 static int update_block_group(struct btrfs_trans_handle *trans,
6061                               struct btrfs_fs_info *info, u64 bytenr,
6062                               u64 num_bytes, int alloc)
6063 {
6064         struct btrfs_block_group_cache *cache = NULL;
6065         u64 total = num_bytes;
6066         u64 old_val;
6067         u64 byte_in_group;
6068         int factor;
6069
6070         /* block accounting for super block */
6071         spin_lock(&info->delalloc_root_lock);
6072         old_val = btrfs_super_bytes_used(info->super_copy);
6073         if (alloc)
6074                 old_val += num_bytes;
6075         else
6076                 old_val -= num_bytes;
6077         btrfs_set_super_bytes_used(info->super_copy, old_val);
6078         spin_unlock(&info->delalloc_root_lock);
6079
6080         while (total) {
6081                 cache = btrfs_lookup_block_group(info, bytenr);
6082                 if (!cache)
6083                         return -ENOENT;
6084                 factor = btrfs_bg_type_to_factor(cache->flags);
6085
6086                 /*
6087                  * If this block group has free space cache written out, we
6088                  * need to make sure to load it if we are removing space.  This
6089                  * is because we need the unpinning stage to actually add the
6090                  * space back to the block group, otherwise we will leak space.
6091                  */
6092                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6093                         cache_block_group(cache, 1);
6094
6095                 byte_in_group = bytenr - cache->key.objectid;
6096                 WARN_ON(byte_in_group > cache->key.offset);
6097
6098                 spin_lock(&cache->space_info->lock);
6099                 spin_lock(&cache->lock);
6100
6101                 if (btrfs_test_opt(info, SPACE_CACHE) &&
6102                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6103                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6104
6105                 old_val = btrfs_block_group_used(&cache->item);
6106                 num_bytes = min(total, cache->key.offset - byte_in_group);
6107                 if (alloc) {
6108                         old_val += num_bytes;
6109                         btrfs_set_block_group_used(&cache->item, old_val);
6110                         cache->reserved -= num_bytes;
6111                         cache->space_info->bytes_reserved -= num_bytes;
6112                         cache->space_info->bytes_used += num_bytes;
6113                         cache->space_info->disk_used += num_bytes * factor;
6114                         spin_unlock(&cache->lock);
6115                         spin_unlock(&cache->space_info->lock);
6116                 } else {
6117                         old_val -= num_bytes;
6118                         btrfs_set_block_group_used(&cache->item, old_val);
6119                         cache->pinned += num_bytes;
6120                         cache->space_info->bytes_pinned += num_bytes;
6121                         cache->space_info->bytes_used -= num_bytes;
6122                         cache->space_info->disk_used -= num_bytes * factor;
6123                         spin_unlock(&cache->lock);
6124                         spin_unlock(&cache->space_info->lock);
6125
6126                         trace_btrfs_space_reservation(info, "pinned",
6127                                                       cache->space_info->flags,
6128                                                       num_bytes, 1);
6129                         percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
6130                                            num_bytes,
6131                                            BTRFS_TOTAL_BYTES_PINNED_BATCH);
6132                         set_extent_dirty(info->pinned_extents,
6133                                          bytenr, bytenr + num_bytes - 1,
6134                                          GFP_NOFS | __GFP_NOFAIL);
6135                 }
6136
6137                 spin_lock(&trans->transaction->dirty_bgs_lock);
6138                 if (list_empty(&cache->dirty_list)) {
6139                         list_add_tail(&cache->dirty_list,
6140                                       &trans->transaction->dirty_bgs);
6141                         trans->transaction->num_dirty_bgs++;
6142                         btrfs_get_block_group(cache);
6143                 }
6144                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6145
6146                 /*
6147                  * No longer have used bytes in this block group, queue it for
6148                  * deletion. We do this after adding the block group to the
6149                  * dirty list to avoid races between cleaner kthread and space
6150                  * cache writeout.
6151                  */
6152                 if (!alloc && old_val == 0)
6153                         btrfs_mark_bg_unused(cache);
6154
6155                 btrfs_put_block_group(cache);
6156                 total -= num_bytes;
6157                 bytenr += num_bytes;
6158         }
6159         return 0;
6160 }
6161
6162 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
6163 {
6164         struct btrfs_block_group_cache *cache;
6165         u64 bytenr;
6166
6167         spin_lock(&fs_info->block_group_cache_lock);
6168         bytenr = fs_info->first_logical_byte;
6169         spin_unlock(&fs_info->block_group_cache_lock);
6170
6171         if (bytenr < (u64)-1)
6172                 return bytenr;
6173
6174         cache = btrfs_lookup_first_block_group(fs_info, search_start);
6175         if (!cache)
6176                 return 0;
6177
6178         bytenr = cache->key.objectid;
6179         btrfs_put_block_group(cache);
6180
6181         return bytenr;
6182 }
6183
6184 static int pin_down_extent(struct btrfs_fs_info *fs_info,
6185                            struct btrfs_block_group_cache *cache,
6186                            u64 bytenr, u64 num_bytes, int reserved)
6187 {
6188         spin_lock(&cache->space_info->lock);
6189         spin_lock(&cache->lock);
6190         cache->pinned += num_bytes;
6191         cache->space_info->bytes_pinned += num_bytes;
6192         if (reserved) {
6193                 cache->reserved -= num_bytes;
6194                 cache->space_info->bytes_reserved -= num_bytes;
6195         }
6196         spin_unlock(&cache->lock);
6197         spin_unlock(&cache->space_info->lock);
6198
6199         trace_btrfs_space_reservation(fs_info, "pinned",
6200                                       cache->space_info->flags, num_bytes, 1);
6201         percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
6202                     num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
6203         set_extent_dirty(fs_info->pinned_extents, bytenr,
6204                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6205         return 0;
6206 }
6207
6208 /*
6209  * this function must be called within transaction
6210  */
6211 int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
6212                      u64 bytenr, u64 num_bytes, int reserved)
6213 {
6214         struct btrfs_block_group_cache *cache;
6215
6216         cache = btrfs_lookup_block_group(fs_info, bytenr);
6217         BUG_ON(!cache); /* Logic error */
6218
6219         pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
6220
6221         btrfs_put_block_group(cache);
6222         return 0;
6223 }
6224
6225 /*
6226  * this function must be called within transaction
6227  */
6228 int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
6229                                     u64 bytenr, u64 num_bytes)
6230 {
6231         struct btrfs_block_group_cache *cache;
6232         int ret;
6233
6234         cache = btrfs_lookup_block_group(fs_info, bytenr);
6235         if (!cache)
6236                 return -EINVAL;
6237
6238         /*
6239          * pull in the free space cache (if any) so that our pin
6240          * removes the free space from the cache.  We have load_only set
6241          * to one because the slow code to read in the free extents does check
6242          * the pinned extents.
6243          */
6244         cache_block_group(cache, 1);
6245
6246         pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
6247
6248         /* remove us from the free space cache (if we're there at all) */
6249         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6250         btrfs_put_block_group(cache);
6251         return ret;
6252 }
6253
6254 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
6255                                    u64 start, u64 num_bytes)
6256 {
6257         int ret;
6258         struct btrfs_block_group_cache *block_group;
6259         struct btrfs_caching_control *caching_ctl;
6260
6261         block_group = btrfs_lookup_block_group(fs_info, start);
6262         if (!block_group)
6263                 return -EINVAL;
6264
6265         cache_block_group(block_group, 0);
6266         caching_ctl = get_caching_control(block_group);
6267
6268         if (!caching_ctl) {
6269                 /* Logic error */
6270                 BUG_ON(!block_group_cache_done(block_group));
6271                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6272         } else {
6273                 mutex_lock(&caching_ctl->mutex);
6274
6275                 if (start >= caching_ctl->progress) {
6276                         ret = add_excluded_extent(fs_info, start, num_bytes);
6277                 } else if (start + num_bytes <= caching_ctl->progress) {
6278                         ret = btrfs_remove_free_space(block_group,
6279                                                       start, num_bytes);
6280                 } else {
6281                         num_bytes = caching_ctl->progress - start;
6282                         ret = btrfs_remove_free_space(block_group,
6283                                                       start, num_bytes);
6284                         if (ret)
6285                                 goto out_lock;
6286
6287                         num_bytes = (start + num_bytes) -
6288                                 caching_ctl->progress;
6289                         start = caching_ctl->progress;
6290                         ret = add_excluded_extent(fs_info, start, num_bytes);
6291                 }
6292 out_lock:
6293                 mutex_unlock(&caching_ctl->mutex);
6294                 put_caching_control(caching_ctl);
6295         }
6296         btrfs_put_block_group(block_group);
6297         return ret;
6298 }
6299
6300 int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
6301                                  struct extent_buffer *eb)
6302 {
6303         struct btrfs_file_extent_item *item;
6304         struct btrfs_key key;
6305         int found_type;
6306         int i;
6307         int ret = 0;
6308
6309         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
6310                 return 0;
6311
6312         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6313                 btrfs_item_key_to_cpu(eb, &key, i);
6314                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6315                         continue;
6316                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6317                 found_type = btrfs_file_extent_type(eb, item);
6318                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6319                         continue;
6320                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6321                         continue;
6322                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6323                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6324                 ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
6325                 if (ret)
6326                         break;
6327         }
6328
6329         return ret;
6330 }
6331
6332 static void
6333 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6334 {
6335         atomic_inc(&bg->reservations);
6336 }
6337
6338 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6339                                         const u64 start)
6340 {
6341         struct btrfs_block_group_cache *bg;
6342
6343         bg = btrfs_lookup_block_group(fs_info, start);
6344         ASSERT(bg);
6345         if (atomic_dec_and_test(&bg->reservations))
6346                 wake_up_var(&bg->reservations);
6347         btrfs_put_block_group(bg);
6348 }
6349
6350 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6351 {
6352         struct btrfs_space_info *space_info = bg->space_info;
6353
6354         ASSERT(bg->ro);
6355
6356         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6357                 return;
6358
6359         /*
6360          * Our block group is read only but before we set it to read only,
6361          * some task might have had allocated an extent from it already, but it
6362          * has not yet created a respective ordered extent (and added it to a
6363          * root's list of ordered extents).
6364          * Therefore wait for any task currently allocating extents, since the
6365          * block group's reservations counter is incremented while a read lock
6366          * on the groups' semaphore is held and decremented after releasing
6367          * the read access on that semaphore and creating the ordered extent.
6368          */
6369         down_write(&space_info->groups_sem);
6370         up_write(&space_info->groups_sem);
6371
6372         wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
6373 }
6374
6375 /**
6376  * btrfs_add_reserved_bytes - update the block_group and space info counters
6377  * @cache:      The cache we are manipulating
6378  * @ram_bytes:  The number of bytes of file content, and will be same to
6379  *              @num_bytes except for the compress path.
6380  * @num_bytes:  The number of bytes in question
6381  * @delalloc:   The blocks are allocated for the delalloc write
6382  *
6383  * This is called by the allocator when it reserves space. If this is a
6384  * reservation and the block group has become read only we cannot make the
6385  * reservation and return -EAGAIN, otherwise this function always succeeds.
6386  */
6387 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6388                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6389 {
6390         struct btrfs_space_info *space_info = cache->space_info;
6391         int ret = 0;
6392
6393         spin_lock(&space_info->lock);
6394         spin_lock(&cache->lock);
6395         if (cache->ro) {
6396                 ret = -EAGAIN;
6397         } else {
6398                 cache->reserved += num_bytes;
6399                 space_info->bytes_reserved += num_bytes;
6400
6401                 trace_btrfs_space_reservation(cache->fs_info,
6402                                 "space_info", space_info->flags,
6403                                 ram_bytes, 0);
6404                 space_info->bytes_may_use -= ram_bytes;
6405                 if (delalloc)
6406                         cache->delalloc_bytes += num_bytes;
6407         }
6408         spin_unlock(&cache->lock);
6409         spin_unlock(&space_info->lock);
6410         return ret;
6411 }
6412
6413 /**
6414  * btrfs_free_reserved_bytes - update the block_group and space info counters
6415  * @cache:      The cache we are manipulating
6416  * @num_bytes:  The number of bytes in question
6417  * @delalloc:   The blocks are allocated for the delalloc write
6418  *
6419  * This is called by somebody who is freeing space that was never actually used
6420  * on disk.  For example if you reserve some space for a new leaf in transaction
6421  * A and before transaction A commits you free that leaf, you call this with
6422  * reserve set to 0 in order to clear the reservation.
6423  */
6424
6425 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6426                                      u64 num_bytes, int delalloc)
6427 {
6428         struct btrfs_space_info *space_info = cache->space_info;
6429         int ret = 0;
6430
6431         spin_lock(&space_info->lock);
6432         spin_lock(&cache->lock);
6433         if (cache->ro)
6434                 space_info->bytes_readonly += num_bytes;
6435         cache->reserved -= num_bytes;
6436         space_info->bytes_reserved -= num_bytes;
6437
6438         if (delalloc)
6439                 cache->delalloc_bytes -= num_bytes;
6440         spin_unlock(&cache->lock);
6441         spin_unlock(&space_info->lock);
6442         return ret;
6443 }
6444 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
6445 {
6446         struct btrfs_caching_control *next;
6447         struct btrfs_caching_control *caching_ctl;
6448         struct btrfs_block_group_cache *cache;
6449
6450         down_write(&fs_info->commit_root_sem);
6451
6452         list_for_each_entry_safe(caching_ctl, next,
6453                                  &fs_info->caching_block_groups, list) {
6454                 cache = caching_ctl->block_group;
6455                 if (block_group_cache_done(cache)) {
6456                         cache->last_byte_to_unpin = (u64)-1;
6457                         list_del_init(&caching_ctl->list);
6458                         put_caching_control(caching_ctl);
6459                 } else {
6460                         cache->last_byte_to_unpin = caching_ctl->progress;
6461                 }
6462         }
6463
6464         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6465                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6466         else
6467                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6468
6469         up_write(&fs_info->commit_root_sem);
6470
6471         update_global_block_rsv(fs_info);
6472 }
6473
6474 /*
6475  * Returns the free cluster for the given space info and sets empty_cluster to
6476  * what it should be based on the mount options.
6477  */
6478 static struct btrfs_free_cluster *
6479 fetch_cluster_info(struct btrfs_fs_info *fs_info,
6480                    struct btrfs_space_info *space_info, u64 *empty_cluster)
6481 {
6482         struct btrfs_free_cluster *ret = NULL;
6483
6484         *empty_cluster = 0;
6485         if (btrfs_mixed_space_info(space_info))
6486                 return ret;
6487
6488         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6489                 ret = &fs_info->meta_alloc_cluster;
6490                 if (btrfs_test_opt(fs_info, SSD))
6491                         *empty_cluster = SZ_2M;
6492                 else
6493                         *empty_cluster = SZ_64K;
6494         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
6495                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
6496                 *empty_cluster = SZ_2M;
6497                 ret = &fs_info->data_alloc_cluster;
6498         }
6499
6500         return ret;
6501 }
6502
6503 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
6504                               u64 start, u64 end,
6505                               const bool return_free_space)
6506 {
6507         struct btrfs_block_group_cache *cache = NULL;
6508         struct btrfs_space_info *space_info;
6509         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6510         struct btrfs_free_cluster *cluster = NULL;
6511         u64 len;
6512         u64 total_unpinned = 0;
6513         u64 empty_cluster = 0;
6514         bool readonly;
6515
6516         while (start <= end) {
6517                 readonly = false;
6518                 if (!cache ||
6519                     start >= cache->key.objectid + cache->key.offset) {
6520                         if (cache)
6521                                 btrfs_put_block_group(cache);
6522                         total_unpinned = 0;
6523                         cache = btrfs_lookup_block_group(fs_info, start);
6524                         BUG_ON(!cache); /* Logic error */
6525
6526                         cluster = fetch_cluster_info(fs_info,
6527                                                      cache->space_info,
6528                                                      &empty_cluster);
6529                         empty_cluster <<= 1;
6530                 }
6531
6532                 len = cache->key.objectid + cache->key.offset - start;
6533                 len = min(len, end + 1 - start);
6534
6535                 if (start < cache->last_byte_to_unpin) {
6536                         len = min(len, cache->last_byte_to_unpin - start);
6537                         if (return_free_space)
6538                                 btrfs_add_free_space(cache, start, len);
6539                 }
6540
6541                 start += len;
6542                 total_unpinned += len;
6543                 space_info = cache->space_info;
6544
6545                 /*
6546                  * If this space cluster has been marked as fragmented and we've
6547                  * unpinned enough in this block group to potentially allow a
6548                  * cluster to be created inside of it go ahead and clear the
6549                  * fragmented check.
6550                  */
6551                 if (cluster && cluster->fragmented &&
6552                     total_unpinned > empty_cluster) {
6553                         spin_lock(&cluster->lock);
6554                         cluster->fragmented = 0;
6555                         spin_unlock(&cluster->lock);
6556                 }
6557
6558                 spin_lock(&space_info->lock);
6559                 spin_lock(&cache->lock);
6560                 cache->pinned -= len;
6561                 space_info->bytes_pinned -= len;
6562
6563                 trace_btrfs_space_reservation(fs_info, "pinned",
6564                                               space_info->flags, len, 0);
6565                 space_info->max_extent_size = 0;
6566                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
6567                             -len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
6568                 if (cache->ro) {
6569                         space_info->bytes_readonly += len;
6570                         readonly = true;
6571                 }
6572                 spin_unlock(&cache->lock);
6573                 if (!readonly && return_free_space &&
6574                     global_rsv->space_info == space_info) {
6575                         u64 to_add = len;
6576
6577                         spin_lock(&global_rsv->lock);
6578                         if (!global_rsv->full) {
6579                                 to_add = min(len, global_rsv->size -
6580                                              global_rsv->reserved);
6581                                 global_rsv->reserved += to_add;
6582                                 space_info->bytes_may_use += to_add;
6583                                 if (global_rsv->reserved >= global_rsv->size)
6584                                         global_rsv->full = 1;
6585                                 trace_btrfs_space_reservation(fs_info,
6586                                                               "space_info",
6587                                                               space_info->flags,
6588                                                               to_add, 1);
6589                                 len -= to_add;
6590                         }
6591                         spin_unlock(&global_rsv->lock);
6592                         /* Add to any tickets we may have */
6593                         if (len)
6594                                 space_info_add_new_bytes(fs_info, space_info,
6595                                                          len);
6596                 }
6597                 spin_unlock(&space_info->lock);
6598         }
6599
6600         if (cache)
6601                 btrfs_put_block_group(cache);
6602         return 0;
6603 }
6604
6605 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
6606 {
6607         struct btrfs_fs_info *fs_info = trans->fs_info;
6608         struct btrfs_block_group_cache *block_group, *tmp;
6609         struct list_head *deleted_bgs;
6610         struct extent_io_tree *unpin;
6611         u64 start;
6612         u64 end;
6613         int ret;
6614
6615         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6616                 unpin = &fs_info->freed_extents[1];
6617         else
6618                 unpin = &fs_info->freed_extents[0];
6619
6620         while (!trans->aborted) {
6621                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6622                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6623                                             EXTENT_DIRTY, NULL);
6624                 if (ret) {
6625                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6626                         break;
6627                 }
6628
6629                 if (btrfs_test_opt(fs_info, DISCARD))
6630                         ret = btrfs_discard_extent(fs_info, start,
6631                                                    end + 1 - start, NULL);
6632
6633                 clear_extent_dirty(unpin, start, end);
6634                 unpin_extent_range(fs_info, start, end, true);
6635                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6636                 cond_resched();
6637         }
6638
6639         /*
6640          * Transaction is finished.  We don't need the lock anymore.  We
6641          * do need to clean up the block groups in case of a transaction
6642          * abort.
6643          */
6644         deleted_bgs = &trans->transaction->deleted_bgs;
6645         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6646                 u64 trimmed = 0;
6647
6648                 ret = -EROFS;
6649                 if (!trans->aborted)
6650                         ret = btrfs_discard_extent(fs_info,
6651                                                    block_group->key.objectid,
6652                                                    block_group->key.offset,
6653                                                    &trimmed);
6654
6655                 list_del_init(&block_group->bg_list);
6656                 btrfs_put_block_group_trimming(block_group);
6657                 btrfs_put_block_group(block_group);
6658
6659                 if (ret) {
6660                         const char *errstr = btrfs_decode_error(ret);
6661                         btrfs_warn(fs_info,
6662                            "discard failed while removing blockgroup: errno=%d %s",
6663                                    ret, errstr);
6664                 }
6665         }
6666
6667         return 0;
6668 }
6669
6670 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6671                                struct btrfs_delayed_ref_node *node, u64 parent,
6672                                u64 root_objectid, u64 owner_objectid,
6673                                u64 owner_offset, int refs_to_drop,
6674                                struct btrfs_delayed_extent_op *extent_op)
6675 {
6676         struct btrfs_fs_info *info = trans->fs_info;
6677         struct btrfs_key key;
6678         struct btrfs_path *path;
6679         struct btrfs_root *extent_root = info->extent_root;
6680         struct extent_buffer *leaf;
6681         struct btrfs_extent_item *ei;
6682         struct btrfs_extent_inline_ref *iref;
6683         int ret;
6684         int is_data;
6685         int extent_slot = 0;
6686         int found_extent = 0;
6687         int num_to_del = 1;
6688         u32 item_size;
6689         u64 refs;
6690         u64 bytenr = node->bytenr;
6691         u64 num_bytes = node->num_bytes;
6692         int last_ref = 0;
6693         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
6694
6695         path = btrfs_alloc_path();
6696         if (!path)
6697                 return -ENOMEM;
6698
6699         path->reada = READA_FORWARD;
6700         path->leave_spinning = 1;
6701
6702         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6703         BUG_ON(!is_data && refs_to_drop != 1);
6704
6705         if (is_data)
6706                 skinny_metadata = false;
6707
6708         ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
6709                                     parent, root_objectid, owner_objectid,
6710                                     owner_offset);
6711         if (ret == 0) {
6712                 extent_slot = path->slots[0];
6713                 while (extent_slot >= 0) {
6714                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6715                                               extent_slot);
6716                         if (key.objectid != bytenr)
6717                                 break;
6718                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6719                             key.offset == num_bytes) {
6720                                 found_extent = 1;
6721                                 break;
6722                         }
6723                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6724                             key.offset == owner_objectid) {
6725                                 found_extent = 1;
6726                                 break;
6727                         }
6728                         if (path->slots[0] - extent_slot > 5)
6729                                 break;
6730                         extent_slot--;
6731                 }
6732
6733                 if (!found_extent) {
6734                         BUG_ON(iref);
6735                         ret = remove_extent_backref(trans, path, NULL,
6736                                                     refs_to_drop,
6737                                                     is_data, &last_ref);
6738                         if (ret) {
6739                                 btrfs_abort_transaction(trans, ret);
6740                                 goto out;
6741                         }
6742                         btrfs_release_path(path);
6743                         path->leave_spinning = 1;
6744
6745                         key.objectid = bytenr;
6746                         key.type = BTRFS_EXTENT_ITEM_KEY;
6747                         key.offset = num_bytes;
6748
6749                         if (!is_data && skinny_metadata) {
6750                                 key.type = BTRFS_METADATA_ITEM_KEY;
6751                                 key.offset = owner_objectid;
6752                         }
6753
6754                         ret = btrfs_search_slot(trans, extent_root,
6755                                                 &key, path, -1, 1);
6756                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6757                                 /*
6758                                  * Couldn't find our skinny metadata item,
6759                                  * see if we have ye olde extent item.
6760                                  */
6761                                 path->slots[0]--;
6762                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6763                                                       path->slots[0]);
6764                                 if (key.objectid == bytenr &&
6765                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6766                                     key.offset == num_bytes)
6767                                         ret = 0;
6768                         }
6769
6770                         if (ret > 0 && skinny_metadata) {
6771                                 skinny_metadata = false;
6772                                 key.objectid = bytenr;
6773                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6774                                 key.offset = num_bytes;
6775                                 btrfs_release_path(path);
6776                                 ret = btrfs_search_slot(trans, extent_root,
6777                                                         &key, path, -1, 1);
6778                         }
6779
6780                         if (ret) {
6781                                 btrfs_err(info,
6782                                           "umm, got %d back from search, was looking for %llu",
6783                                           ret, bytenr);
6784                                 if (ret > 0)
6785                                         btrfs_print_leaf(path->nodes[0]);
6786                         }
6787                         if (ret < 0) {
6788                                 btrfs_abort_transaction(trans, ret);
6789                                 goto out;
6790                         }
6791                         extent_slot = path->slots[0];
6792                 }
6793         } else if (WARN_ON(ret == -ENOENT)) {
6794                 btrfs_print_leaf(path->nodes[0]);
6795                 btrfs_err(info,
6796                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6797                         bytenr, parent, root_objectid, owner_objectid,
6798                         owner_offset);
6799                 btrfs_abort_transaction(trans, ret);
6800                 goto out;
6801         } else {
6802                 btrfs_abort_transaction(trans, ret);
6803                 goto out;
6804         }
6805
6806         leaf = path->nodes[0];
6807         item_size = btrfs_item_size_nr(leaf, extent_slot);
6808         if (unlikely(item_size < sizeof(*ei))) {
6809                 ret = -EINVAL;
6810                 btrfs_print_v0_err(info);
6811                 btrfs_abort_transaction(trans, ret);
6812                 goto out;
6813         }
6814         ei = btrfs_item_ptr(leaf, extent_slot,
6815                             struct btrfs_extent_item);
6816         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6817             key.type == BTRFS_EXTENT_ITEM_KEY) {
6818                 struct btrfs_tree_block_info *bi;
6819                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6820                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6821                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6822         }
6823
6824         refs = btrfs_extent_refs(leaf, ei);
6825         if (refs < refs_to_drop) {
6826                 btrfs_err(info,
6827                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
6828                           refs_to_drop, refs, bytenr);
6829                 ret = -EINVAL;
6830                 btrfs_abort_transaction(trans, ret);
6831                 goto out;
6832         }
6833         refs -= refs_to_drop;
6834
6835         if (refs > 0) {
6836                 if (extent_op)
6837                         __run_delayed_extent_op(extent_op, leaf, ei);
6838                 /*
6839                  * In the case of inline back ref, reference count will
6840                  * be updated by remove_extent_backref
6841                  */
6842                 if (iref) {
6843                         BUG_ON(!found_extent);
6844                 } else {
6845                         btrfs_set_extent_refs(leaf, ei, refs);
6846                         btrfs_mark_buffer_dirty(leaf);
6847                 }
6848                 if (found_extent) {
6849                         ret = remove_extent_backref(trans, path, iref,
6850                                                     refs_to_drop, is_data,
6851                                                     &last_ref);
6852                         if (ret) {
6853                                 btrfs_abort_transaction(trans, ret);
6854                                 goto out;
6855                         }
6856                 }
6857         } else {
6858                 if (found_extent) {
6859                         BUG_ON(is_data && refs_to_drop !=
6860                                extent_data_ref_count(path, iref));
6861                         if (iref) {
6862                                 BUG_ON(path->slots[0] != extent_slot);
6863                         } else {
6864                                 BUG_ON(path->slots[0] != extent_slot + 1);
6865                                 path->slots[0] = extent_slot;
6866                                 num_to_del = 2;
6867                         }
6868                 }
6869
6870                 last_ref = 1;
6871                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6872                                       num_to_del);
6873                 if (ret) {
6874                         btrfs_abort_transaction(trans, ret);
6875                         goto out;
6876                 }
6877                 btrfs_release_path(path);
6878
6879                 if (is_data) {
6880                         ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
6881                         if (ret) {
6882                                 btrfs_abort_transaction(trans, ret);
6883                                 goto out;
6884                         }
6885                 }
6886
6887                 ret = add_to_free_space_tree(trans, bytenr, num_bytes);
6888                 if (ret) {
6889                         btrfs_abort_transaction(trans, ret);
6890                         goto out;
6891                 }
6892
6893                 ret = update_block_group(trans, info, bytenr, num_bytes, 0);
6894                 if (ret) {
6895                         btrfs_abort_transaction(trans, ret);
6896                         goto out;
6897                 }
6898         }
6899         btrfs_release_path(path);
6900
6901 out:
6902         btrfs_free_path(path);
6903         return ret;
6904 }
6905
6906 /*
6907  * when we free an block, it is possible (and likely) that we free the last
6908  * delayed ref for that extent as well.  This searches the delayed ref tree for
6909  * a given extent, and if there are no other delayed refs to be processed, it
6910  * removes it from the tree.
6911  */
6912 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6913                                       u64 bytenr)
6914 {
6915         struct btrfs_delayed_ref_head *head;
6916         struct btrfs_delayed_ref_root *delayed_refs;
6917         int ret = 0;
6918
6919         delayed_refs = &trans->transaction->delayed_refs;
6920         spin_lock(&delayed_refs->lock);
6921         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
6922         if (!head)
6923                 goto out_delayed_unlock;
6924
6925         spin_lock(&head->lock);
6926         if (!RB_EMPTY_ROOT(&head->ref_tree))
6927                 goto out;
6928
6929         if (head->extent_op) {
6930                 if (!head->must_insert_reserved)
6931                         goto out;
6932                 btrfs_free_delayed_extent_op(head->extent_op);
6933                 head->extent_op = NULL;
6934         }
6935
6936         /*
6937          * waiting for the lock here would deadlock.  If someone else has it
6938          * locked they are already in the process of dropping it anyway
6939          */
6940         if (!mutex_trylock(&head->mutex))
6941                 goto out;
6942
6943         /*
6944          * at this point we have a head with no other entries.  Go
6945          * ahead and process it.
6946          */
6947         rb_erase(&head->href_node, &delayed_refs->href_root);
6948         RB_CLEAR_NODE(&head->href_node);
6949         atomic_dec(&delayed_refs->num_entries);
6950
6951         /*
6952          * we don't take a ref on the node because we're removing it from the
6953          * tree, so we just steal the ref the tree was holding.
6954          */
6955         delayed_refs->num_heads--;
6956         if (head->processing == 0)
6957                 delayed_refs->num_heads_ready--;
6958         head->processing = 0;
6959         spin_unlock(&head->lock);
6960         spin_unlock(&delayed_refs->lock);
6961
6962         BUG_ON(head->extent_op);
6963         if (head->must_insert_reserved)
6964                 ret = 1;
6965
6966         mutex_unlock(&head->mutex);
6967         btrfs_put_delayed_ref_head(head);
6968         return ret;
6969 out:
6970         spin_unlock(&head->lock);
6971
6972 out_delayed_unlock:
6973         spin_unlock(&delayed_refs->lock);
6974         return 0;
6975 }
6976
6977 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6978                            struct btrfs_root *root,
6979                            struct extent_buffer *buf,
6980                            u64 parent, int last_ref)
6981 {
6982         struct btrfs_fs_info *fs_info = root->fs_info;
6983         int pin = 1;
6984         int ret;
6985
6986         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6987                 int old_ref_mod, new_ref_mod;
6988
6989                 btrfs_ref_tree_mod(root, buf->start, buf->len, parent,
6990                                    root->root_key.objectid,
6991                                    btrfs_header_level(buf), 0,
6992                                    BTRFS_DROP_DELAYED_REF);
6993                 ret = btrfs_add_delayed_tree_ref(trans, buf->start,
6994                                                  buf->len, parent,
6995                                                  root->root_key.objectid,
6996                                                  btrfs_header_level(buf),
6997                                                  BTRFS_DROP_DELAYED_REF, NULL,
6998                                                  &old_ref_mod, &new_ref_mod);
6999                 BUG_ON(ret); /* -ENOMEM */
7000                 pin = old_ref_mod >= 0 && new_ref_mod < 0;
7001         }
7002
7003         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
7004                 struct btrfs_block_group_cache *cache;
7005
7006                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7007                         ret = check_ref_cleanup(trans, buf->start);
7008                         if (!ret)
7009                                 goto out;
7010                 }
7011
7012                 pin = 0;
7013                 cache = btrfs_lookup_block_group(fs_info, buf->start);
7014
7015                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7016                         pin_down_extent(fs_info, cache, buf->start,
7017                                         buf->len, 1);
7018                         btrfs_put_block_group(cache);
7019                         goto out;
7020                 }
7021
7022                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7023
7024                 btrfs_add_free_space(cache, buf->start, buf->len);
7025                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7026                 btrfs_put_block_group(cache);
7027                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
7028         }
7029 out:
7030         if (pin)
7031                 add_pinned_bytes(fs_info, buf->len, true,
7032                                  root->root_key.objectid);
7033
7034         if (last_ref) {
7035                 /*
7036                  * Deleting the buffer, clear the corrupt flag since it doesn't
7037                  * matter anymore.
7038                  */
7039                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7040         }
7041 }
7042
7043 /* Can return -ENOMEM */
7044 int btrfs_free_extent(struct btrfs_trans_handle *trans,
7045                       struct btrfs_root *root,
7046                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7047                       u64 owner, u64 offset)
7048 {
7049         struct btrfs_fs_info *fs_info = root->fs_info;
7050         int old_ref_mod, new_ref_mod;
7051         int ret;
7052
7053         if (btrfs_is_testing(fs_info))
7054                 return 0;
7055
7056         if (root_objectid != BTRFS_TREE_LOG_OBJECTID)
7057                 btrfs_ref_tree_mod(root, bytenr, num_bytes, parent,
7058                                    root_objectid, owner, offset,
7059                                    BTRFS_DROP_DELAYED_REF);
7060
7061         /*
7062          * tree log blocks never actually go into the extent allocation
7063          * tree, just update pinning info and exit early.
7064          */
7065         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7066                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7067                 /* unlocks the pinned mutex */
7068                 btrfs_pin_extent(fs_info, bytenr, num_bytes, 1);
7069                 old_ref_mod = new_ref_mod = 0;
7070                 ret = 0;
7071         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7072                 ret = btrfs_add_delayed_tree_ref(trans, bytenr,
7073                                                  num_bytes, parent,
7074                                                  root_objectid, (int)owner,
7075                                                  BTRFS_DROP_DELAYED_REF, NULL,
7076                                                  &old_ref_mod, &new_ref_mod);
7077         } else {
7078                 ret = btrfs_add_delayed_data_ref(trans, bytenr,
7079                                                  num_bytes, parent,
7080                                                  root_objectid, owner, offset,
7081                                                  0, BTRFS_DROP_DELAYED_REF,
7082                                                  &old_ref_mod, &new_ref_mod);
7083         }
7084
7085         if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0) {
7086                 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
7087
7088                 add_pinned_bytes(fs_info, num_bytes, metadata, root_objectid);
7089         }
7090
7091         return ret;
7092 }
7093
7094 /*
7095  * when we wait for progress in the block group caching, its because
7096  * our allocation attempt failed at least once.  So, we must sleep
7097  * and let some progress happen before we try again.
7098  *
7099  * This function will sleep at least once waiting for new free space to
7100  * show up, and then it will check the block group free space numbers
7101  * for our min num_bytes.  Another option is to have it go ahead
7102  * and look in the rbtree for a free extent of a given size, but this
7103  * is a good start.
7104  *
7105  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7106  * any of the information in this block group.
7107  */
7108 static noinline void
7109 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7110                                 u64 num_bytes)
7111 {
7112         struct btrfs_caching_control *caching_ctl;
7113
7114         caching_ctl = get_caching_control(cache);
7115         if (!caching_ctl)
7116                 return;
7117
7118         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7119                    (cache->free_space_ctl->free_space >= num_bytes));
7120
7121         put_caching_control(caching_ctl);
7122 }
7123
7124 static noinline int
7125 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7126 {
7127         struct btrfs_caching_control *caching_ctl;
7128         int ret = 0;
7129
7130         caching_ctl = get_caching_control(cache);
7131         if (!caching_ctl)
7132                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7133
7134         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7135         if (cache->cached == BTRFS_CACHE_ERROR)
7136                 ret = -EIO;
7137         put_caching_control(caching_ctl);
7138         return ret;
7139 }
7140
7141 enum btrfs_loop_type {
7142         LOOP_CACHING_NOWAIT = 0,
7143         LOOP_CACHING_WAIT = 1,
7144         LOOP_ALLOC_CHUNK = 2,
7145         LOOP_NO_EMPTY_SIZE = 3,
7146 };
7147
7148 static inline void
7149 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7150                        int delalloc)
7151 {
7152         if (delalloc)
7153                 down_read(&cache->data_rwsem);
7154 }
7155
7156 static inline void
7157 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7158                        int delalloc)
7159 {
7160         btrfs_get_block_group(cache);
7161         if (delalloc)
7162                 down_read(&cache->data_rwsem);
7163 }
7164
7165 static struct btrfs_block_group_cache *
7166 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7167                    struct btrfs_free_cluster *cluster,
7168                    int delalloc)
7169 {
7170         struct btrfs_block_group_cache *used_bg = NULL;
7171
7172         spin_lock(&cluster->refill_lock);
7173         while (1) {
7174                 used_bg = cluster->block_group;
7175                 if (!used_bg)
7176                         return NULL;
7177
7178                 if (used_bg == block_group)
7179                         return used_bg;
7180
7181                 btrfs_get_block_group(used_bg);
7182
7183                 if (!delalloc)
7184                         return used_bg;
7185
7186                 if (down_read_trylock(&used_bg->data_rwsem))
7187                         return used_bg;
7188
7189                 spin_unlock(&cluster->refill_lock);
7190
7191                 /* We should only have one-level nested. */
7192                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
7193
7194                 spin_lock(&cluster->refill_lock);
7195                 if (used_bg == cluster->block_group)
7196                         return used_bg;
7197
7198                 up_read(&used_bg->data_rwsem);
7199                 btrfs_put_block_group(used_bg);
7200         }
7201 }
7202
7203 static inline void
7204 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7205                          int delalloc)
7206 {
7207         if (delalloc)
7208                 up_read(&cache->data_rwsem);
7209         btrfs_put_block_group(cache);
7210 }
7211
7212 /*
7213  * walks the btree of allocated extents and find a hole of a given size.
7214  * The key ins is changed to record the hole:
7215  * ins->objectid == start position
7216  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7217  * ins->offset == the size of the hole.
7218  * Any available blocks before search_start are skipped.
7219  *
7220  * If there is no suitable free space, we will record the max size of
7221  * the free space extent currently.
7222  */
7223 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
7224                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7225                                 u64 hint_byte, struct btrfs_key *ins,
7226                                 u64 flags, int delalloc)
7227 {
7228         int ret = 0;
7229         struct btrfs_root *root = fs_info->extent_root;
7230         struct btrfs_free_cluster *last_ptr = NULL;
7231         struct btrfs_block_group_cache *block_group = NULL;
7232         u64 search_start = 0;
7233         u64 max_extent_size = 0;
7234         u64 empty_cluster = 0;
7235         struct btrfs_space_info *space_info;
7236         int loop = 0;
7237         int index = btrfs_bg_flags_to_raid_index(flags);
7238         bool failed_cluster_refill = false;
7239         bool failed_alloc = false;
7240         bool use_cluster = true;
7241         bool have_caching_bg = false;
7242         bool orig_have_caching_bg = false;
7243         bool full_search = false;
7244
7245         WARN_ON(num_bytes < fs_info->sectorsize);
7246         ins->type = BTRFS_EXTENT_ITEM_KEY;
7247         ins->objectid = 0;
7248         ins->offset = 0;
7249
7250         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
7251
7252         space_info = __find_space_info(fs_info, flags);
7253         if (!space_info) {
7254                 btrfs_err(fs_info, "No space info for %llu", flags);
7255                 return -ENOSPC;
7256         }
7257
7258         /*
7259          * If our free space is heavily fragmented we may not be able to make
7260          * big contiguous allocations, so instead of doing the expensive search
7261          * for free space, simply return ENOSPC with our max_extent_size so we
7262          * can go ahead and search for a more manageable chunk.
7263          *
7264          * If our max_extent_size is large enough for our allocation simply
7265          * disable clustering since we will likely not be able to find enough
7266          * space to create a cluster and induce latency trying.
7267          */
7268         if (unlikely(space_info->max_extent_size)) {
7269                 spin_lock(&space_info->lock);
7270                 if (space_info->max_extent_size &&
7271                     num_bytes > space_info->max_extent_size) {
7272                         ins->offset = space_info->max_extent_size;
7273                         spin_unlock(&space_info->lock);
7274                         return -ENOSPC;
7275                 } else if (space_info->max_extent_size) {
7276                         use_cluster = false;
7277                 }
7278                 spin_unlock(&space_info->lock);
7279         }
7280
7281         last_ptr = fetch_cluster_info(fs_info, space_info, &empty_cluster);
7282         if (last_ptr) {
7283                 spin_lock(&last_ptr->lock);
7284                 if (last_ptr->block_group)
7285                         hint_byte = last_ptr->window_start;
7286                 if (last_ptr->fragmented) {
7287                         /*
7288                          * We still set window_start so we can keep track of the
7289                          * last place we found an allocation to try and save
7290                          * some time.
7291                          */
7292                         hint_byte = last_ptr->window_start;
7293                         use_cluster = false;
7294                 }
7295                 spin_unlock(&last_ptr->lock);
7296         }
7297
7298         search_start = max(search_start, first_logical_byte(fs_info, 0));
7299         search_start = max(search_start, hint_byte);
7300         if (search_start == hint_byte) {
7301                 block_group = btrfs_lookup_block_group(fs_info, search_start);
7302                 /*
7303                  * we don't want to use the block group if it doesn't match our
7304                  * allocation bits, or if its not cached.
7305                  *
7306                  * However if we are re-searching with an ideal block group
7307                  * picked out then we don't care that the block group is cached.
7308                  */
7309                 if (block_group && block_group_bits(block_group, flags) &&
7310                     block_group->cached != BTRFS_CACHE_NO) {
7311                         down_read(&space_info->groups_sem);
7312                         if (list_empty(&block_group->list) ||
7313                             block_group->ro) {
7314                                 /*
7315                                  * someone is removing this block group,
7316                                  * we can't jump into the have_block_group
7317                                  * target because our list pointers are not
7318                                  * valid
7319                                  */
7320                                 btrfs_put_block_group(block_group);
7321                                 up_read(&space_info->groups_sem);
7322                         } else {
7323                                 index = btrfs_bg_flags_to_raid_index(
7324                                                 block_group->flags);
7325                                 btrfs_lock_block_group(block_group, delalloc);
7326                                 goto have_block_group;
7327                         }
7328                 } else if (block_group) {
7329                         btrfs_put_block_group(block_group);
7330                 }
7331         }
7332 search:
7333         have_caching_bg = false;
7334         if (index == 0 || index == btrfs_bg_flags_to_raid_index(flags))
7335                 full_search = true;
7336         down_read(&space_info->groups_sem);
7337         list_for_each_entry(block_group, &space_info->block_groups[index],
7338                             list) {
7339                 u64 offset;
7340                 int cached;
7341
7342                 /* If the block group is read-only, we can skip it entirely. */
7343                 if (unlikely(block_group->ro))
7344                         continue;
7345
7346                 btrfs_grab_block_group(block_group, delalloc);
7347                 search_start = block_group->key.objectid;
7348
7349                 /*
7350                  * this can happen if we end up cycling through all the
7351                  * raid types, but we want to make sure we only allocate
7352                  * for the proper type.
7353                  */
7354                 if (!block_group_bits(block_group, flags)) {
7355                         u64 extra = BTRFS_BLOCK_GROUP_DUP |
7356                                 BTRFS_BLOCK_GROUP_RAID1 |
7357                                 BTRFS_BLOCK_GROUP_RAID5 |
7358                                 BTRFS_BLOCK_GROUP_RAID6 |
7359                                 BTRFS_BLOCK_GROUP_RAID10;
7360
7361                         /*
7362                          * if they asked for extra copies and this block group
7363                          * doesn't provide them, bail.  This does allow us to
7364                          * fill raid0 from raid1.
7365                          */
7366                         if ((flags & extra) && !(block_group->flags & extra))
7367                                 goto loop;
7368                 }
7369
7370 have_block_group:
7371                 cached = block_group_cache_done(block_group);
7372                 if (unlikely(!cached)) {
7373                         have_caching_bg = true;
7374                         ret = cache_block_group(block_group, 0);
7375                         BUG_ON(ret < 0);
7376                         ret = 0;
7377                 }
7378
7379                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7380                         goto loop;
7381
7382                 /*
7383                  * Ok we want to try and use the cluster allocator, so
7384                  * lets look there
7385                  */
7386                 if (last_ptr && use_cluster) {
7387                         struct btrfs_block_group_cache *used_block_group;
7388                         unsigned long aligned_cluster;
7389                         /*
7390                          * the refill lock keeps out other
7391                          * people trying to start a new cluster
7392                          */
7393                         used_block_group = btrfs_lock_cluster(block_group,
7394                                                               last_ptr,
7395                                                               delalloc);
7396                         if (!used_block_group)
7397                                 goto refill_cluster;
7398
7399                         if (used_block_group != block_group &&
7400                             (used_block_group->ro ||
7401                              !block_group_bits(used_block_group, flags)))
7402                                 goto release_cluster;
7403
7404                         offset = btrfs_alloc_from_cluster(used_block_group,
7405                                                 last_ptr,
7406                                                 num_bytes,
7407                                                 used_block_group->key.objectid,
7408                                                 &max_extent_size);
7409                         if (offset) {
7410                                 /* we have a block, we're done */
7411                                 spin_unlock(&last_ptr->refill_lock);
7412                                 trace_btrfs_reserve_extent_cluster(
7413                                                 used_block_group,
7414                                                 search_start, num_bytes);
7415                                 if (used_block_group != block_group) {
7416                                         btrfs_release_block_group(block_group,
7417                                                                   delalloc);
7418                                         block_group = used_block_group;
7419                                 }
7420                                 goto checks;
7421                         }
7422
7423                         WARN_ON(last_ptr->block_group != used_block_group);
7424 release_cluster:
7425                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7426                          * set up a new clusters, so lets just skip it
7427                          * and let the allocator find whatever block
7428                          * it can find.  If we reach this point, we
7429                          * will have tried the cluster allocator
7430                          * plenty of times and not have found
7431                          * anything, so we are likely way too
7432                          * fragmented for the clustering stuff to find
7433                          * anything.
7434                          *
7435                          * However, if the cluster is taken from the
7436                          * current block group, release the cluster
7437                          * first, so that we stand a better chance of
7438                          * succeeding in the unclustered
7439                          * allocation.  */
7440                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7441                             used_block_group != block_group) {
7442                                 spin_unlock(&last_ptr->refill_lock);
7443                                 btrfs_release_block_group(used_block_group,
7444                                                           delalloc);
7445                                 goto unclustered_alloc;
7446                         }
7447
7448                         /*
7449                          * this cluster didn't work out, free it and
7450                          * start over
7451                          */
7452                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7453
7454                         if (used_block_group != block_group)
7455                                 btrfs_release_block_group(used_block_group,
7456                                                           delalloc);
7457 refill_cluster:
7458                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7459                                 spin_unlock(&last_ptr->refill_lock);
7460                                 goto unclustered_alloc;
7461                         }
7462
7463                         aligned_cluster = max_t(unsigned long,
7464                                                 empty_cluster + empty_size,
7465                                               block_group->full_stripe_len);
7466
7467                         /* allocate a cluster in this block group */
7468                         ret = btrfs_find_space_cluster(fs_info, block_group,
7469                                                        last_ptr, search_start,
7470                                                        num_bytes,
7471                                                        aligned_cluster);
7472                         if (ret == 0) {
7473                                 /*
7474                                  * now pull our allocation out of this
7475                                  * cluster
7476                                  */
7477                                 offset = btrfs_alloc_from_cluster(block_group,
7478                                                         last_ptr,
7479                                                         num_bytes,
7480                                                         search_start,
7481                                                         &max_extent_size);
7482                                 if (offset) {
7483                                         /* we found one, proceed */
7484                                         spin_unlock(&last_ptr->refill_lock);
7485                                         trace_btrfs_reserve_extent_cluster(
7486                                                 block_group, search_start,
7487                                                 num_bytes);
7488                                         goto checks;
7489                                 }
7490                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7491                                    && !failed_cluster_refill) {
7492                                 spin_unlock(&last_ptr->refill_lock);
7493
7494                                 failed_cluster_refill = true;
7495                                 wait_block_group_cache_progress(block_group,
7496                                        num_bytes + empty_cluster + empty_size);
7497                                 goto have_block_group;
7498                         }
7499
7500                         /*
7501                          * at this point we either didn't find a cluster
7502                          * or we weren't able to allocate a block from our
7503                          * cluster.  Free the cluster we've been trying
7504                          * to use, and go to the next block group
7505                          */
7506                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7507                         spin_unlock(&last_ptr->refill_lock);
7508                         goto loop;
7509                 }
7510
7511 unclustered_alloc:
7512                 /*
7513                  * We are doing an unclustered alloc, set the fragmented flag so
7514                  * we don't bother trying to setup a cluster again until we get
7515                  * more space.
7516                  */
7517                 if (unlikely(last_ptr)) {
7518                         spin_lock(&last_ptr->lock);
7519                         last_ptr->fragmented = 1;
7520                         spin_unlock(&last_ptr->lock);
7521                 }
7522                 if (cached) {
7523                         struct btrfs_free_space_ctl *ctl =
7524                                 block_group->free_space_ctl;
7525
7526                         spin_lock(&ctl->tree_lock);
7527                         if (ctl->free_space <
7528                             num_bytes + empty_cluster + empty_size) {
7529                                 if (ctl->free_space > max_extent_size)
7530                                         max_extent_size = ctl->free_space;
7531                                 spin_unlock(&ctl->tree_lock);
7532                                 goto loop;
7533                         }
7534                         spin_unlock(&ctl->tree_lock);
7535                 }
7536
7537                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7538                                                     num_bytes, empty_size,
7539                                                     &max_extent_size);
7540                 /*
7541                  * If we didn't find a chunk, and we haven't failed on this
7542                  * block group before, and this block group is in the middle of
7543                  * caching and we are ok with waiting, then go ahead and wait
7544                  * for progress to be made, and set failed_alloc to true.
7545                  *
7546                  * If failed_alloc is true then we've already waited on this
7547                  * block group once and should move on to the next block group.
7548                  */
7549                 if (!offset && !failed_alloc && !cached &&
7550                     loop > LOOP_CACHING_NOWAIT) {
7551                         wait_block_group_cache_progress(block_group,
7552                                                 num_bytes + empty_size);
7553                         failed_alloc = true;
7554                         goto have_block_group;
7555                 } else if (!offset) {
7556                         goto loop;
7557                 }
7558 checks:
7559                 search_start = round_up(offset, fs_info->stripesize);
7560
7561                 /* move on to the next group */
7562                 if (search_start + num_bytes >
7563                     block_group->key.objectid + block_group->key.offset) {
7564                         btrfs_add_free_space(block_group, offset, num_bytes);
7565                         goto loop;
7566                 }
7567
7568                 if (offset < search_start)
7569                         btrfs_add_free_space(block_group, offset,
7570                                              search_start - offset);
7571
7572                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7573                                 num_bytes, delalloc);
7574                 if (ret == -EAGAIN) {
7575                         btrfs_add_free_space(block_group, offset, num_bytes);
7576                         goto loop;
7577                 }
7578                 btrfs_inc_block_group_reservations(block_group);
7579
7580                 /* we are all good, lets return */
7581                 ins->objectid = search_start;
7582                 ins->offset = num_bytes;
7583
7584                 trace_btrfs_reserve_extent(block_group, search_start, num_bytes);
7585                 btrfs_release_block_group(block_group, delalloc);
7586                 break;
7587 loop:
7588                 failed_cluster_refill = false;
7589                 failed_alloc = false;
7590                 BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
7591                        index);
7592                 btrfs_release_block_group(block_group, delalloc);
7593                 cond_resched();
7594         }
7595         up_read(&space_info->groups_sem);
7596
7597         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7598                 && !orig_have_caching_bg)
7599                 orig_have_caching_bg = true;
7600
7601         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7602                 goto search;
7603
7604         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7605                 goto search;
7606
7607         /*
7608          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7609          *                      caching kthreads as we move along
7610          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7611          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7612          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7613          *                      again
7614          */
7615         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7616                 index = 0;
7617                 if (loop == LOOP_CACHING_NOWAIT) {
7618                         /*
7619                          * We want to skip the LOOP_CACHING_WAIT step if we
7620                          * don't have any uncached bgs and we've already done a
7621                          * full search through.
7622                          */
7623                         if (orig_have_caching_bg || !full_search)
7624                                 loop = LOOP_CACHING_WAIT;
7625                         else
7626                                 loop = LOOP_ALLOC_CHUNK;
7627                 } else {
7628                         loop++;
7629                 }
7630
7631                 if (loop == LOOP_ALLOC_CHUNK) {
7632                         struct btrfs_trans_handle *trans;
7633                         int exist = 0;
7634
7635                         trans = current->journal_info;
7636                         if (trans)
7637                                 exist = 1;
7638                         else
7639                                 trans = btrfs_join_transaction(root);
7640
7641                         if (IS_ERR(trans)) {
7642                                 ret = PTR_ERR(trans);
7643                                 goto out;
7644                         }
7645
7646                         ret = do_chunk_alloc(trans, flags, CHUNK_ALLOC_FORCE);
7647
7648                         /*
7649                          * If we can't allocate a new chunk we've already looped
7650                          * through at least once, move on to the NO_EMPTY_SIZE
7651                          * case.
7652                          */
7653                         if (ret == -ENOSPC)
7654                                 loop = LOOP_NO_EMPTY_SIZE;
7655
7656                         /*
7657                          * Do not bail out on ENOSPC since we
7658                          * can do more things.
7659                          */
7660                         if (ret < 0 && ret != -ENOSPC)
7661                                 btrfs_abort_transaction(trans, ret);
7662                         else
7663                                 ret = 0;
7664                         if (!exist)
7665                                 btrfs_end_transaction(trans);
7666                         if (ret)
7667                                 goto out;
7668                 }
7669
7670                 if (loop == LOOP_NO_EMPTY_SIZE) {
7671                         /*
7672                          * Don't loop again if we already have no empty_size and
7673                          * no empty_cluster.
7674                          */
7675                         if (empty_size == 0 &&
7676                             empty_cluster == 0) {
7677                                 ret = -ENOSPC;
7678                                 goto out;
7679                         }
7680                         empty_size = 0;
7681                         empty_cluster = 0;
7682                 }
7683
7684                 goto search;
7685         } else if (!ins->objectid) {
7686                 ret = -ENOSPC;
7687         } else if (ins->objectid) {
7688                 if (!use_cluster && last_ptr) {
7689                         spin_lock(&last_ptr->lock);
7690                         last_ptr->window_start = ins->objectid;
7691                         spin_unlock(&last_ptr->lock);
7692                 }
7693                 ret = 0;
7694         }
7695 out:
7696         if (ret == -ENOSPC) {
7697                 spin_lock(&space_info->lock);
7698                 space_info->max_extent_size = max_extent_size;
7699                 spin_unlock(&space_info->lock);
7700                 ins->offset = max_extent_size;
7701         }
7702         return ret;
7703 }
7704
7705 static void dump_space_info(struct btrfs_fs_info *fs_info,
7706                             struct btrfs_space_info *info, u64 bytes,
7707                             int dump_block_groups)
7708 {
7709         struct btrfs_block_group_cache *cache;
7710         int index = 0;
7711
7712         spin_lock(&info->lock);
7713         btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
7714                    info->flags,
7715                    info->total_bytes - btrfs_space_info_used(info, true),
7716                    info->full ? "" : "not ");
7717         btrfs_info(fs_info,
7718                 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
7719                 info->total_bytes, info->bytes_used, info->bytes_pinned,
7720                 info->bytes_reserved, info->bytes_may_use,
7721                 info->bytes_readonly);
7722         spin_unlock(&info->lock);
7723
7724         if (!dump_block_groups)
7725                 return;
7726
7727         down_read(&info->groups_sem);
7728 again:
7729         list_for_each_entry(cache, &info->block_groups[index], list) {
7730                 spin_lock(&cache->lock);
7731                 btrfs_info(fs_info,
7732                         "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
7733                         cache->key.objectid, cache->key.offset,
7734                         btrfs_block_group_used(&cache->item), cache->pinned,
7735                         cache->reserved, cache->ro ? "[readonly]" : "");
7736                 btrfs_dump_free_space(cache, bytes);
7737                 spin_unlock(&cache->lock);
7738         }
7739         if (++index < BTRFS_NR_RAID_TYPES)
7740                 goto again;
7741         up_read(&info->groups_sem);
7742 }
7743
7744 /*
7745  * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
7746  *                        hole that is at least as big as @num_bytes.
7747  *
7748  * @root           -    The root that will contain this extent
7749  *
7750  * @ram_bytes      -    The amount of space in ram that @num_bytes take. This
7751  *                      is used for accounting purposes. This value differs
7752  *                      from @num_bytes only in the case of compressed extents.
7753  *
7754  * @num_bytes      -    Number of bytes to allocate on-disk.
7755  *
7756  * @min_alloc_size -    Indicates the minimum amount of space that the
7757  *                      allocator should try to satisfy. In some cases
7758  *                      @num_bytes may be larger than what is required and if
7759  *                      the filesystem is fragmented then allocation fails.
7760  *                      However, the presence of @min_alloc_size gives a
7761  *                      chance to try and satisfy the smaller allocation.
7762  *
7763  * @empty_size     -    A hint that you plan on doing more COW. This is the
7764  *                      size in bytes the allocator should try to find free
7765  *                      next to the block it returns.  This is just a hint and
7766  *                      may be ignored by the allocator.
7767  *
7768  * @hint_byte      -    Hint to the allocator to start searching above the byte
7769  *                      address passed. It might be ignored.
7770  *
7771  * @ins            -    This key is modified to record the found hole. It will
7772  *                      have the following values:
7773  *                      ins->objectid == start position
7774  *                      ins->flags = BTRFS_EXTENT_ITEM_KEY
7775  *                      ins->offset == the size of the hole.
7776  *
7777  * @is_data        -    Boolean flag indicating whether an extent is
7778  *                      allocated for data (true) or metadata (false)
7779  *
7780  * @delalloc       -    Boolean flag indicating whether this allocation is for
7781  *                      delalloc or not. If 'true' data_rwsem of block groups
7782  *                      is going to be acquired.
7783  *
7784  *
7785  * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
7786  * case -ENOSPC is returned then @ins->offset will contain the size of the
7787  * largest available hole the allocator managed to find.
7788  */
7789 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7790                          u64 num_bytes, u64 min_alloc_size,
7791                          u64 empty_size, u64 hint_byte,
7792                          struct btrfs_key *ins, int is_data, int delalloc)
7793 {
7794         struct btrfs_fs_info *fs_info = root->fs_info;
7795         bool final_tried = num_bytes == min_alloc_size;
7796         u64 flags;
7797         int ret;
7798
7799         flags = get_alloc_profile_by_root(root, is_data);
7800 again:
7801         WARN_ON(num_bytes < fs_info->sectorsize);
7802         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
7803                                hint_byte, ins, flags, delalloc);
7804         if (!ret && !is_data) {
7805                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
7806         } else if (ret == -ENOSPC) {
7807                 if (!final_tried && ins->offset) {
7808                         num_bytes = min(num_bytes >> 1, ins->offset);
7809                         num_bytes = round_down(num_bytes,
7810                                                fs_info->sectorsize);
7811                         num_bytes = max(num_bytes, min_alloc_size);
7812                         ram_bytes = num_bytes;
7813                         if (num_bytes == min_alloc_size)
7814                                 final_tried = true;
7815                         goto again;
7816                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
7817                         struct btrfs_space_info *sinfo;
7818
7819                         sinfo = __find_space_info(fs_info, flags);
7820                         btrfs_err(fs_info,
7821                                   "allocation failed flags %llu, wanted %llu",
7822                                   flags, num_bytes);
7823                         if (sinfo)
7824                                 dump_space_info(fs_info, sinfo, num_bytes, 1);
7825                 }
7826         }
7827
7828         return ret;
7829 }
7830
7831 static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
7832                                         u64 start, u64 len,
7833                                         int pin, int delalloc)
7834 {
7835         struct btrfs_block_group_cache *cache;
7836         int ret = 0;
7837
7838         cache = btrfs_lookup_block_group(fs_info, start);
7839         if (!cache) {
7840                 btrfs_err(fs_info, "Unable to find block group for %llu",
7841                           start);
7842                 return -ENOSPC;
7843         }
7844
7845         if (pin)
7846                 pin_down_extent(fs_info, cache, start, len, 1);
7847         else {
7848                 if (btrfs_test_opt(fs_info, DISCARD))
7849                         ret = btrfs_discard_extent(fs_info, start, len, NULL);
7850                 btrfs_add_free_space(cache, start, len);
7851                 btrfs_free_reserved_bytes(cache, len, delalloc);
7852                 trace_btrfs_reserved_extent_free(fs_info, start, len);
7853         }
7854
7855         btrfs_put_block_group(cache);
7856         return ret;
7857 }
7858
7859 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
7860                                u64 start, u64 len, int delalloc)
7861 {
7862         return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
7863 }
7864
7865 int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
7866                                        u64 start, u64 len)
7867 {
7868         return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
7869 }
7870
7871 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7872                                       u64 parent, u64 root_objectid,
7873                                       u64 flags, u64 owner, u64 offset,
7874                                       struct btrfs_key *ins, int ref_mod)
7875 {
7876         struct btrfs_fs_info *fs_info = trans->fs_info;
7877         int ret;
7878         struct btrfs_extent_item *extent_item;
7879         struct btrfs_extent_inline_ref *iref;
7880         struct btrfs_path *path;
7881         struct extent_buffer *leaf;
7882         int type;
7883         u32 size;
7884
7885         if (parent > 0)
7886                 type = BTRFS_SHARED_DATA_REF_KEY;
7887         else
7888                 type = BTRFS_EXTENT_DATA_REF_KEY;
7889
7890         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7891
7892         path = btrfs_alloc_path();
7893         if (!path)
7894                 return -ENOMEM;
7895
7896         path->leave_spinning = 1;
7897         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7898                                       ins, size);
7899         if (ret) {
7900                 btrfs_free_path(path);
7901                 return ret;
7902         }
7903
7904         leaf = path->nodes[0];
7905         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7906                                      struct btrfs_extent_item);
7907         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7908         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7909         btrfs_set_extent_flags(leaf, extent_item,
7910                                flags | BTRFS_EXTENT_FLAG_DATA);
7911
7912         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7913         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7914         if (parent > 0) {
7915                 struct btrfs_shared_data_ref *ref;
7916                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7917                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7918                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7919         } else {
7920                 struct btrfs_extent_data_ref *ref;
7921                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7922                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7923                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7924                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7925                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7926         }
7927
7928         btrfs_mark_buffer_dirty(path->nodes[0]);
7929         btrfs_free_path(path);
7930
7931         ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
7932         if (ret)
7933                 return ret;
7934
7935         ret = update_block_group(trans, fs_info, ins->objectid, ins->offset, 1);
7936         if (ret) { /* -ENOENT, logic error */
7937                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7938                         ins->objectid, ins->offset);
7939                 BUG();
7940         }
7941         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
7942         return ret;
7943 }
7944
7945 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7946                                      struct btrfs_delayed_ref_node *node,
7947                                      struct btrfs_delayed_extent_op *extent_op)
7948 {
7949         struct btrfs_fs_info *fs_info = trans->fs_info;
7950         int ret;
7951         struct btrfs_extent_item *extent_item;
7952         struct btrfs_key extent_key;
7953         struct btrfs_tree_block_info *block_info;
7954         struct btrfs_extent_inline_ref *iref;
7955         struct btrfs_path *path;
7956         struct extent_buffer *leaf;
7957         struct btrfs_delayed_tree_ref *ref;
7958         u32 size = sizeof(*extent_item) + sizeof(*iref);
7959         u64 num_bytes;
7960         u64 flags = extent_op->flags_to_set;
7961         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
7962
7963         ref = btrfs_delayed_node_to_tree_ref(node);
7964
7965         extent_key.objectid = node->bytenr;
7966         if (skinny_metadata) {
7967                 extent_key.offset = ref->level;
7968                 extent_key.type = BTRFS_METADATA_ITEM_KEY;
7969                 num_bytes = fs_info->nodesize;
7970         } else {
7971                 extent_key.offset = node->num_bytes;
7972                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
7973                 size += sizeof(*block_info);
7974                 num_bytes = node->num_bytes;
7975         }
7976
7977         path = btrfs_alloc_path();
7978         if (!path) {
7979                 btrfs_free_and_pin_reserved_extent(fs_info,
7980                                                    extent_key.objectid,
7981                                                    fs_info->nodesize);
7982                 return -ENOMEM;
7983         }
7984
7985         path->leave_spinning = 1;
7986         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7987                                       &extent_key, size);
7988         if (ret) {
7989                 btrfs_free_path(path);
7990                 btrfs_free_and_pin_reserved_extent(fs_info,
7991                                                    extent_key.objectid,
7992                                                    fs_info->nodesize);
7993                 return ret;
7994         }
7995
7996         leaf = path->nodes[0];
7997         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7998                                      struct btrfs_extent_item);
7999         btrfs_set_extent_refs(leaf, extent_item, 1);
8000         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8001         btrfs_set_extent_flags(leaf, extent_item,
8002                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8003
8004         if (skinny_metadata) {
8005                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8006         } else {
8007                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8008                 btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
8009                 btrfs_set_tree_block_level(leaf, block_info, ref->level);
8010                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8011         }
8012
8013         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
8014                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8015                 btrfs_set_extent_inline_ref_type(leaf, iref,
8016                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8017                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
8018         } else {
8019                 btrfs_set_extent_inline_ref_type(leaf, iref,
8020                                                  BTRFS_TREE_BLOCK_REF_KEY);
8021                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
8022         }
8023
8024         btrfs_mark_buffer_dirty(leaf);
8025         btrfs_free_path(path);
8026
8027         ret = remove_from_free_space_tree(trans, extent_key.objectid,
8028                                           num_bytes);
8029         if (ret)
8030                 return ret;
8031
8032         ret = update_block_group(trans, fs_info, extent_key.objectid,
8033                                  fs_info->nodesize, 1);
8034         if (ret) { /* -ENOENT, logic error */
8035                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8036                         extent_key.objectid, extent_key.offset);
8037                 BUG();
8038         }
8039
8040         trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
8041                                           fs_info->nodesize);
8042         return ret;
8043 }
8044
8045 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8046                                      struct btrfs_root *root, u64 owner,
8047                                      u64 offset, u64 ram_bytes,
8048                                      struct btrfs_key *ins)
8049 {
8050         int ret;
8051
8052         BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
8053
8054         btrfs_ref_tree_mod(root, ins->objectid, ins->offset, 0,
8055                            root->root_key.objectid, owner, offset,
8056                            BTRFS_ADD_DELAYED_EXTENT);
8057
8058         ret = btrfs_add_delayed_data_ref(trans, ins->objectid,
8059                                          ins->offset, 0,
8060                                          root->root_key.objectid, owner,
8061                                          offset, ram_bytes,
8062                                          BTRFS_ADD_DELAYED_EXTENT, NULL, NULL);
8063         return ret;
8064 }
8065
8066 /*
8067  * this is used by the tree logging recovery code.  It records that
8068  * an extent has been allocated and makes sure to clear the free
8069  * space cache bits as well
8070  */
8071 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8072                                    u64 root_objectid, u64 owner, u64 offset,
8073                                    struct btrfs_key *ins)
8074 {
8075         struct btrfs_fs_info *fs_info = trans->fs_info;
8076         int ret;
8077         struct btrfs_block_group_cache *block_group;
8078         struct btrfs_space_info *space_info;
8079
8080         /*
8081          * Mixed block groups will exclude before processing the log so we only
8082          * need to do the exclude dance if this fs isn't mixed.
8083          */
8084         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
8085                 ret = __exclude_logged_extent(fs_info, ins->objectid,
8086                                               ins->offset);
8087                 if (ret)
8088                         return ret;
8089         }
8090
8091         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
8092         if (!block_group)
8093                 return -EINVAL;
8094
8095         space_info = block_group->space_info;
8096         spin_lock(&space_info->lock);
8097         spin_lock(&block_group->lock);
8098         space_info->bytes_reserved += ins->offset;
8099         block_group->reserved += ins->offset;
8100         spin_unlock(&block_group->lock);
8101         spin_unlock(&space_info->lock);
8102
8103         ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
8104                                          offset, ins, 1);
8105         btrfs_put_block_group(block_group);
8106         return ret;
8107 }
8108
8109 static struct extent_buffer *
8110 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8111                       u64 bytenr, int level, u64 owner)
8112 {
8113         struct btrfs_fs_info *fs_info = root->fs_info;
8114         struct extent_buffer *buf;
8115
8116         buf = btrfs_find_create_tree_block(fs_info, bytenr);
8117         if (IS_ERR(buf))
8118                 return buf;
8119
8120         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8121         btrfs_tree_lock(buf);
8122         clean_tree_block(fs_info, buf);
8123         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8124
8125         btrfs_set_lock_blocking(buf);
8126         set_extent_buffer_uptodate(buf);
8127
8128         memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
8129         btrfs_set_header_level(buf, level);
8130         btrfs_set_header_bytenr(buf, buf->start);
8131         btrfs_set_header_generation(buf, trans->transid);
8132         btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
8133         btrfs_set_header_owner(buf, owner);
8134         write_extent_buffer_fsid(buf, fs_info->fsid);
8135         write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
8136         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8137                 buf->log_index = root->log_transid % 2;
8138                 /*
8139                  * we allow two log transactions at a time, use different
8140                  * EXENT bit to differentiate dirty pages.
8141                  */
8142                 if (buf->log_index == 0)
8143                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8144                                         buf->start + buf->len - 1, GFP_NOFS);
8145                 else
8146                         set_extent_new(&root->dirty_log_pages, buf->start,
8147                                         buf->start + buf->len - 1);
8148         } else {
8149                 buf->log_index = -1;
8150                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8151                          buf->start + buf->len - 1, GFP_NOFS);
8152         }
8153         trans->dirty = true;
8154         /* this returns a buffer locked for blocking */
8155         return buf;
8156 }
8157
8158 static struct btrfs_block_rsv *
8159 use_block_rsv(struct btrfs_trans_handle *trans,
8160               struct btrfs_root *root, u32 blocksize)
8161 {
8162         struct btrfs_fs_info *fs_info = root->fs_info;
8163         struct btrfs_block_rsv *block_rsv;
8164         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
8165         int ret;
8166         bool global_updated = false;
8167
8168         block_rsv = get_block_rsv(trans, root);
8169
8170         if (unlikely(block_rsv->size == 0))
8171                 goto try_reserve;
8172 again:
8173         ret = block_rsv_use_bytes(block_rsv, blocksize);
8174         if (!ret)
8175                 return block_rsv;
8176
8177         if (block_rsv->failfast)
8178                 return ERR_PTR(ret);
8179
8180         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8181                 global_updated = true;
8182                 update_global_block_rsv(fs_info);
8183                 goto again;
8184         }
8185
8186         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8187                 static DEFINE_RATELIMIT_STATE(_rs,
8188                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8189                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8190                 if (__ratelimit(&_rs))
8191                         WARN(1, KERN_DEBUG
8192                                 "BTRFS: block rsv returned %d\n", ret);
8193         }
8194 try_reserve:
8195         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8196                                      BTRFS_RESERVE_NO_FLUSH);
8197         if (!ret)
8198                 return block_rsv;
8199         /*
8200          * If we couldn't reserve metadata bytes try and use some from
8201          * the global reserve if its space type is the same as the global
8202          * reservation.
8203          */
8204         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8205             block_rsv->space_info == global_rsv->space_info) {
8206                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8207                 if (!ret)
8208                         return global_rsv;
8209         }
8210         return ERR_PTR(ret);
8211 }
8212
8213 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8214                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8215 {
8216         block_rsv_add_bytes(block_rsv, blocksize, false);
8217         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0, NULL);
8218 }
8219
8220 /*
8221  * finds a free extent and does all the dirty work required for allocation
8222  * returns the tree buffer or an ERR_PTR on error.
8223  */
8224 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8225                                              struct btrfs_root *root,
8226                                              u64 parent, u64 root_objectid,
8227                                              const struct btrfs_disk_key *key,
8228                                              int level, u64 hint,
8229                                              u64 empty_size)
8230 {
8231         struct btrfs_fs_info *fs_info = root->fs_info;
8232         struct btrfs_key ins;
8233         struct btrfs_block_rsv *block_rsv;
8234         struct extent_buffer *buf;
8235         struct btrfs_delayed_extent_op *extent_op;
8236         u64 flags = 0;
8237         int ret;
8238         u32 blocksize = fs_info->nodesize;
8239         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8240
8241 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8242         if (btrfs_is_testing(fs_info)) {
8243                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8244                                             level, root_objectid);
8245                 if (!IS_ERR(buf))
8246                         root->alloc_bytenr += blocksize;
8247                 return buf;
8248         }
8249 #endif
8250
8251         block_rsv = use_block_rsv(trans, root, blocksize);
8252         if (IS_ERR(block_rsv))
8253                 return ERR_CAST(block_rsv);
8254
8255         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8256                                    empty_size, hint, &ins, 0, 0);
8257         if (ret)
8258                 goto out_unuse;
8259
8260         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
8261                                     root_objectid);
8262         if (IS_ERR(buf)) {
8263                 ret = PTR_ERR(buf);
8264                 goto out_free_reserved;
8265         }
8266
8267         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8268                 if (parent == 0)
8269                         parent = ins.objectid;
8270                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8271         } else
8272                 BUG_ON(parent > 0);
8273
8274         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8275                 extent_op = btrfs_alloc_delayed_extent_op();
8276                 if (!extent_op) {
8277                         ret = -ENOMEM;
8278                         goto out_free_buf;
8279                 }
8280                 if (key)
8281                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8282                 else
8283                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8284                 extent_op->flags_to_set = flags;
8285                 extent_op->update_key = skinny_metadata ? false : true;
8286                 extent_op->update_flags = true;
8287                 extent_op->is_data = false;
8288                 extent_op->level = level;
8289
8290                 btrfs_ref_tree_mod(root, ins.objectid, ins.offset, parent,
8291                                    root_objectid, level, 0,
8292                                    BTRFS_ADD_DELAYED_EXTENT);
8293                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
8294                                                  ins.offset, parent,
8295                                                  root_objectid, level,
8296                                                  BTRFS_ADD_DELAYED_EXTENT,
8297                                                  extent_op, NULL, NULL);
8298                 if (ret)
8299                         goto out_free_delayed;
8300         }
8301         return buf;
8302
8303 out_free_delayed:
8304         btrfs_free_delayed_extent_op(extent_op);
8305 out_free_buf:
8306         free_extent_buffer(buf);
8307 out_free_reserved:
8308         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
8309 out_unuse:
8310         unuse_block_rsv(fs_info, block_rsv, blocksize);
8311         return ERR_PTR(ret);
8312 }
8313
8314 struct walk_control {
8315         u64 refs[BTRFS_MAX_LEVEL];
8316         u64 flags[BTRFS_MAX_LEVEL];
8317         struct btrfs_key update_progress;
8318         int stage;
8319         int level;
8320         int shared_level;
8321         int update_ref;
8322         int keep_locks;
8323         int reada_slot;
8324         int reada_count;
8325 };
8326
8327 #define DROP_REFERENCE  1
8328 #define UPDATE_BACKREF  2
8329
8330 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8331                                      struct btrfs_root *root,
8332                                      struct walk_control *wc,
8333                                      struct btrfs_path *path)
8334 {
8335         struct btrfs_fs_info *fs_info = root->fs_info;
8336         u64 bytenr;
8337         u64 generation;
8338         u64 refs;
8339         u64 flags;
8340         u32 nritems;
8341         struct btrfs_key key;
8342         struct extent_buffer *eb;
8343         int ret;
8344         int slot;
8345         int nread = 0;
8346
8347         if (path->slots[wc->level] < wc->reada_slot) {
8348                 wc->reada_count = wc->reada_count * 2 / 3;
8349                 wc->reada_count = max(wc->reada_count, 2);
8350         } else {
8351                 wc->reada_count = wc->reada_count * 3 / 2;
8352                 wc->reada_count = min_t(int, wc->reada_count,
8353                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
8354         }
8355
8356         eb = path->nodes[wc->level];
8357         nritems = btrfs_header_nritems(eb);
8358
8359         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8360                 if (nread >= wc->reada_count)
8361                         break;
8362
8363                 cond_resched();
8364                 bytenr = btrfs_node_blockptr(eb, slot);
8365                 generation = btrfs_node_ptr_generation(eb, slot);
8366
8367                 if (slot == path->slots[wc->level])
8368                         goto reada;
8369
8370                 if (wc->stage == UPDATE_BACKREF &&
8371                     generation <= root->root_key.offset)
8372                         continue;
8373
8374                 /* We don't lock the tree block, it's OK to be racy here */
8375                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
8376                                                wc->level - 1, 1, &refs,
8377                                                &flags);
8378                 /* We don't care about errors in readahead. */
8379                 if (ret < 0)
8380                         continue;
8381                 BUG_ON(refs == 0);
8382
8383                 if (wc->stage == DROP_REFERENCE) {
8384                         if (refs == 1)
8385                                 goto reada;
8386
8387                         if (wc->level == 1 &&
8388                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8389                                 continue;
8390                         if (!wc->update_ref ||
8391                             generation <= root->root_key.offset)
8392                                 continue;
8393                         btrfs_node_key_to_cpu(eb, &key, slot);
8394                         ret = btrfs_comp_cpu_keys(&key,
8395                                                   &wc->update_progress);
8396                         if (ret < 0)
8397                                 continue;
8398                 } else {
8399                         if (wc->level == 1 &&
8400                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8401                                 continue;
8402                 }
8403 reada:
8404                 readahead_tree_block(fs_info, bytenr);
8405                 nread++;
8406         }
8407         wc->reada_slot = slot;
8408 }
8409
8410 /*
8411  * helper to process tree block while walking down the tree.
8412  *
8413  * when wc->stage == UPDATE_BACKREF, this function updates
8414  * back refs for pointers in the block.
8415  *
8416  * NOTE: return value 1 means we should stop walking down.
8417  */
8418 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8419                                    struct btrfs_root *root,
8420                                    struct btrfs_path *path,
8421                                    struct walk_control *wc, int lookup_info)
8422 {
8423         struct btrfs_fs_info *fs_info = root->fs_info;
8424         int level = wc->level;
8425         struct extent_buffer *eb = path->nodes[level];
8426         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8427         int ret;
8428
8429         if (wc->stage == UPDATE_BACKREF &&
8430             btrfs_header_owner(eb) != root->root_key.objectid)
8431                 return 1;
8432
8433         /*
8434          * when reference count of tree block is 1, it won't increase
8435          * again. once full backref flag is set, we never clear it.
8436          */
8437         if (lookup_info &&
8438             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8439              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8440                 BUG_ON(!path->locks[level]);
8441                 ret = btrfs_lookup_extent_info(trans, fs_info,
8442                                                eb->start, level, 1,
8443                                                &wc->refs[level],
8444                                                &wc->flags[level]);
8445                 BUG_ON(ret == -ENOMEM);
8446                 if (ret)
8447                         return ret;
8448                 BUG_ON(wc->refs[level] == 0);
8449         }
8450
8451         if (wc->stage == DROP_REFERENCE) {
8452                 if (wc->refs[level] > 1)
8453                         return 1;
8454
8455                 if (path->locks[level] && !wc->keep_locks) {
8456                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8457                         path->locks[level] = 0;
8458                 }
8459                 return 0;
8460         }
8461
8462         /* wc->stage == UPDATE_BACKREF */
8463         if (!(wc->flags[level] & flag)) {
8464                 BUG_ON(!path->locks[level]);
8465                 ret = btrfs_inc_ref(trans, root, eb, 1);
8466                 BUG_ON(ret); /* -ENOMEM */
8467                 ret = btrfs_dec_ref(trans, root, eb, 0);
8468                 BUG_ON(ret); /* -ENOMEM */
8469                 ret = btrfs_set_disk_extent_flags(trans, fs_info, eb->start,
8470                                                   eb->len, flag,
8471                                                   btrfs_header_level(eb), 0);
8472                 BUG_ON(ret); /* -ENOMEM */
8473                 wc->flags[level] |= flag;
8474         }
8475
8476         /*
8477          * the block is shared by multiple trees, so it's not good to
8478          * keep the tree lock
8479          */
8480         if (path->locks[level] && level > 0) {
8481                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8482                 path->locks[level] = 0;
8483         }
8484         return 0;
8485 }
8486
8487 /*
8488  * helper to process tree block pointer.
8489  *
8490  * when wc->stage == DROP_REFERENCE, this function checks
8491  * reference count of the block pointed to. if the block
8492  * is shared and we need update back refs for the subtree
8493  * rooted at the block, this function changes wc->stage to
8494  * UPDATE_BACKREF. if the block is shared and there is no
8495  * need to update back, this function drops the reference
8496  * to the block.
8497  *
8498  * NOTE: return value 1 means we should stop walking down.
8499  */
8500 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8501                                  struct btrfs_root *root,
8502                                  struct btrfs_path *path,
8503                                  struct walk_control *wc, int *lookup_info)
8504 {
8505         struct btrfs_fs_info *fs_info = root->fs_info;
8506         u64 bytenr;
8507         u64 generation;
8508         u64 parent;
8509         u32 blocksize;
8510         struct btrfs_key key;
8511         struct btrfs_key first_key;
8512         struct extent_buffer *next;
8513         int level = wc->level;
8514         int reada = 0;
8515         int ret = 0;
8516         bool need_account = false;
8517
8518         generation = btrfs_node_ptr_generation(path->nodes[level],
8519                                                path->slots[level]);
8520         /*
8521          * if the lower level block was created before the snapshot
8522          * was created, we know there is no need to update back refs
8523          * for the subtree
8524          */
8525         if (wc->stage == UPDATE_BACKREF &&
8526             generation <= root->root_key.offset) {
8527                 *lookup_info = 1;
8528                 return 1;
8529         }
8530
8531         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8532         btrfs_node_key_to_cpu(path->nodes[level], &first_key,
8533                               path->slots[level]);
8534         blocksize = fs_info->nodesize;
8535
8536         next = find_extent_buffer(fs_info, bytenr);
8537         if (!next) {
8538                 next = btrfs_find_create_tree_block(fs_info, bytenr);
8539                 if (IS_ERR(next))
8540                         return PTR_ERR(next);
8541
8542                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8543                                                level - 1);
8544                 reada = 1;
8545         }
8546         btrfs_tree_lock(next);
8547         btrfs_set_lock_blocking(next);
8548
8549         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
8550                                        &wc->refs[level - 1],
8551                                        &wc->flags[level - 1]);
8552         if (ret < 0)
8553                 goto out_unlock;
8554
8555         if (unlikely(wc->refs[level - 1] == 0)) {
8556                 btrfs_err(fs_info, "Missing references.");
8557                 ret = -EIO;
8558                 goto out_unlock;
8559         }
8560         *lookup_info = 0;
8561
8562         if (wc->stage == DROP_REFERENCE) {
8563                 if (wc->refs[level - 1] > 1) {
8564                         need_account = true;
8565                         if (level == 1 &&
8566                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8567                                 goto skip;
8568
8569                         if (!wc->update_ref ||
8570                             generation <= root->root_key.offset)
8571                                 goto skip;
8572
8573                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8574                                               path->slots[level]);
8575                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8576                         if (ret < 0)
8577                                 goto skip;
8578
8579                         wc->stage = UPDATE_BACKREF;
8580                         wc->shared_level = level - 1;
8581                 }
8582         } else {
8583                 if (level == 1 &&
8584                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8585                         goto skip;
8586         }
8587
8588         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8589                 btrfs_tree_unlock(next);
8590                 free_extent_buffer(next);
8591                 next = NULL;
8592                 *lookup_info = 1;
8593         }
8594
8595         if (!next) {
8596                 if (reada && level == 1)
8597                         reada_walk_down(trans, root, wc, path);
8598                 next = read_tree_block(fs_info, bytenr, generation, level - 1,
8599                                        &first_key);
8600                 if (IS_ERR(next)) {
8601                         return PTR_ERR(next);
8602                 } else if (!extent_buffer_uptodate(next)) {
8603                         free_extent_buffer(next);
8604                         return -EIO;
8605                 }
8606                 btrfs_tree_lock(next);
8607                 btrfs_set_lock_blocking(next);
8608         }
8609
8610         level--;
8611         ASSERT(level == btrfs_header_level(next));
8612         if (level != btrfs_header_level(next)) {
8613                 btrfs_err(root->fs_info, "mismatched level");
8614                 ret = -EIO;
8615                 goto out_unlock;
8616         }
8617         path->nodes[level] = next;
8618         path->slots[level] = 0;
8619         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8620         wc->level = level;
8621         if (wc->level == 1)
8622                 wc->reada_slot = 0;
8623         return 0;
8624 skip:
8625         wc->refs[level - 1] = 0;
8626         wc->flags[level - 1] = 0;
8627         if (wc->stage == DROP_REFERENCE) {
8628                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8629                         parent = path->nodes[level]->start;
8630                 } else {
8631                         ASSERT(root->root_key.objectid ==
8632                                btrfs_header_owner(path->nodes[level]));
8633                         if (root->root_key.objectid !=
8634                             btrfs_header_owner(path->nodes[level])) {
8635                                 btrfs_err(root->fs_info,
8636                                                 "mismatched block owner");
8637                                 ret = -EIO;
8638                                 goto out_unlock;
8639                         }
8640                         parent = 0;
8641                 }
8642
8643                 if (need_account) {
8644                         ret = btrfs_qgroup_trace_subtree(trans, next,
8645                                                          generation, level - 1);
8646                         if (ret) {
8647                                 btrfs_err_rl(fs_info,
8648                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8649                                              ret);
8650                         }
8651                 }
8652                 ret = btrfs_free_extent(trans, root, bytenr, blocksize,
8653                                         parent, root->root_key.objectid,
8654                                         level - 1, 0);
8655                 if (ret)
8656                         goto out_unlock;
8657         }
8658
8659         *lookup_info = 1;
8660         ret = 1;
8661
8662 out_unlock:
8663         btrfs_tree_unlock(next);
8664         free_extent_buffer(next);
8665
8666         return ret;
8667 }
8668
8669 /*
8670  * helper to process tree block while walking up the tree.
8671  *
8672  * when wc->stage == DROP_REFERENCE, this function drops
8673  * reference count on the block.
8674  *
8675  * when wc->stage == UPDATE_BACKREF, this function changes
8676  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8677  * to UPDATE_BACKREF previously while processing the block.
8678  *
8679  * NOTE: return value 1 means we should stop walking up.
8680  */
8681 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8682                                  struct btrfs_root *root,
8683                                  struct btrfs_path *path,
8684                                  struct walk_control *wc)
8685 {
8686         struct btrfs_fs_info *fs_info = root->fs_info;
8687         int ret;
8688         int level = wc->level;
8689         struct extent_buffer *eb = path->nodes[level];
8690         u64 parent = 0;
8691
8692         if (wc->stage == UPDATE_BACKREF) {
8693                 BUG_ON(wc->shared_level < level);
8694                 if (level < wc->shared_level)
8695                         goto out;
8696
8697                 ret = find_next_key(path, level + 1, &wc->update_progress);
8698                 if (ret > 0)
8699                         wc->update_ref = 0;
8700
8701                 wc->stage = DROP_REFERENCE;
8702                 wc->shared_level = -1;
8703                 path->slots[level] = 0;
8704
8705                 /*
8706                  * check reference count again if the block isn't locked.
8707                  * we should start walking down the tree again if reference
8708                  * count is one.
8709                  */
8710                 if (!path->locks[level]) {
8711                         BUG_ON(level == 0);
8712                         btrfs_tree_lock(eb);
8713                         btrfs_set_lock_blocking(eb);
8714                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8715
8716                         ret = btrfs_lookup_extent_info(trans, fs_info,
8717                                                        eb->start, level, 1,
8718                                                        &wc->refs[level],
8719                                                        &wc->flags[level]);
8720                         if (ret < 0) {
8721                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8722                                 path->locks[level] = 0;
8723                                 return ret;
8724                         }
8725                         BUG_ON(wc->refs[level] == 0);
8726                         if (wc->refs[level] == 1) {
8727                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8728                                 path->locks[level] = 0;
8729                                 return 1;
8730                         }
8731                 }
8732         }
8733
8734         /* wc->stage == DROP_REFERENCE */
8735         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8736
8737         if (wc->refs[level] == 1) {
8738                 if (level == 0) {
8739                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8740                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8741                         else
8742                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8743                         BUG_ON(ret); /* -ENOMEM */
8744                         ret = btrfs_qgroup_trace_leaf_items(trans, eb);
8745                         if (ret) {
8746                                 btrfs_err_rl(fs_info,
8747                                              "error %d accounting leaf items. Quota is out of sync, rescan required.",
8748                                              ret);
8749                         }
8750                 }
8751                 /* make block locked assertion in clean_tree_block happy */
8752                 if (!path->locks[level] &&
8753                     btrfs_header_generation(eb) == trans->transid) {
8754                         btrfs_tree_lock(eb);
8755                         btrfs_set_lock_blocking(eb);
8756                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8757                 }
8758                 clean_tree_block(fs_info, eb);
8759         }
8760
8761         if (eb == root->node) {
8762                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8763                         parent = eb->start;
8764                 else
8765                         BUG_ON(root->root_key.objectid !=
8766                                btrfs_header_owner(eb));
8767         } else {
8768                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8769                         parent = path->nodes[level + 1]->start;
8770                 else
8771                         BUG_ON(root->root_key.objectid !=
8772                                btrfs_header_owner(path->nodes[level + 1]));
8773         }
8774
8775         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8776 out:
8777         wc->refs[level] = 0;
8778         wc->flags[level] = 0;
8779         return 0;
8780 }
8781
8782 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8783                                    struct btrfs_root *root,
8784                                    struct btrfs_path *path,
8785                                    struct walk_control *wc)
8786 {
8787         int level = wc->level;
8788         int lookup_info = 1;
8789         int ret;
8790
8791         while (level >= 0) {
8792                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8793                 if (ret > 0)
8794                         break;
8795
8796                 if (level == 0)
8797                         break;
8798
8799                 if (path->slots[level] >=
8800                     btrfs_header_nritems(path->nodes[level]))
8801                         break;
8802
8803                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8804                 if (ret > 0) {
8805                         path->slots[level]++;
8806                         continue;
8807                 } else if (ret < 0)
8808                         return ret;
8809                 level = wc->level;
8810         }
8811         return 0;
8812 }
8813
8814 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8815                                  struct btrfs_root *root,
8816                                  struct btrfs_path *path,
8817                                  struct walk_control *wc, int max_level)
8818 {
8819         int level = wc->level;
8820         int ret;
8821
8822         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8823         while (level < max_level && path->nodes[level]) {
8824                 wc->level = level;
8825                 if (path->slots[level] + 1 <
8826                     btrfs_header_nritems(path->nodes[level])) {
8827                         path->slots[level]++;
8828                         return 0;
8829                 } else {
8830                         ret = walk_up_proc(trans, root, path, wc);
8831                         if (ret > 0)
8832                                 return 0;
8833
8834                         if (path->locks[level]) {
8835                                 btrfs_tree_unlock_rw(path->nodes[level],
8836                                                      path->locks[level]);
8837                                 path->locks[level] = 0;
8838                         }
8839                         free_extent_buffer(path->nodes[level]);
8840                         path->nodes[level] = NULL;
8841                         level++;
8842                 }
8843         }
8844         return 1;
8845 }
8846
8847 /*
8848  * drop a subvolume tree.
8849  *
8850  * this function traverses the tree freeing any blocks that only
8851  * referenced by the tree.
8852  *
8853  * when a shared tree block is found. this function decreases its
8854  * reference count by one. if update_ref is true, this function
8855  * also make sure backrefs for the shared block and all lower level
8856  * blocks are properly updated.
8857  *
8858  * If called with for_reloc == 0, may exit early with -EAGAIN
8859  */
8860 int btrfs_drop_snapshot(struct btrfs_root *root,
8861                          struct btrfs_block_rsv *block_rsv, int update_ref,
8862                          int for_reloc)
8863 {
8864         struct btrfs_fs_info *fs_info = root->fs_info;
8865         struct btrfs_path *path;
8866         struct btrfs_trans_handle *trans;
8867         struct btrfs_root *tree_root = fs_info->tree_root;
8868         struct btrfs_root_item *root_item = &root->root_item;
8869         struct walk_control *wc;
8870         struct btrfs_key key;
8871         int err = 0;
8872         int ret;
8873         int level;
8874         bool root_dropped = false;
8875
8876         btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
8877
8878         path = btrfs_alloc_path();
8879         if (!path) {
8880                 err = -ENOMEM;
8881                 goto out;
8882         }
8883
8884         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8885         if (!wc) {
8886                 btrfs_free_path(path);
8887                 err = -ENOMEM;
8888                 goto out;
8889         }
8890
8891         trans = btrfs_start_transaction(tree_root, 0);
8892         if (IS_ERR(trans)) {
8893                 err = PTR_ERR(trans);
8894                 goto out_free;
8895         }
8896
8897         if (block_rsv)
8898                 trans->block_rsv = block_rsv;
8899
8900         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8901                 level = btrfs_header_level(root->node);
8902                 path->nodes[level] = btrfs_lock_root_node(root);
8903                 btrfs_set_lock_blocking(path->nodes[level]);
8904                 path->slots[level] = 0;
8905                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8906                 memset(&wc->update_progress, 0,
8907                        sizeof(wc->update_progress));
8908         } else {
8909                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8910                 memcpy(&wc->update_progress, &key,
8911                        sizeof(wc->update_progress));
8912
8913                 level = root_item->drop_level;
8914                 BUG_ON(level == 0);
8915                 path->lowest_level = level;
8916                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8917                 path->lowest_level = 0;
8918                 if (ret < 0) {
8919                         err = ret;
8920                         goto out_end_trans;
8921                 }
8922                 WARN_ON(ret > 0);
8923
8924                 /*
8925                  * unlock our path, this is safe because only this
8926                  * function is allowed to delete this snapshot
8927                  */
8928                 btrfs_unlock_up_safe(path, 0);
8929
8930                 level = btrfs_header_level(root->node);
8931                 while (1) {
8932                         btrfs_tree_lock(path->nodes[level]);
8933                         btrfs_set_lock_blocking(path->nodes[level]);
8934                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8935
8936                         ret = btrfs_lookup_extent_info(trans, fs_info,
8937                                                 path->nodes[level]->start,
8938                                                 level, 1, &wc->refs[level],
8939                                                 &wc->flags[level]);
8940                         if (ret < 0) {
8941                                 err = ret;
8942                                 goto out_end_trans;
8943                         }
8944                         BUG_ON(wc->refs[level] == 0);
8945
8946                         if (level == root_item->drop_level)
8947                                 break;
8948
8949                         btrfs_tree_unlock(path->nodes[level]);
8950                         path->locks[level] = 0;
8951                         WARN_ON(wc->refs[level] != 1);
8952                         level--;
8953                 }
8954         }
8955
8956         wc->level = level;
8957         wc->shared_level = -1;
8958         wc->stage = DROP_REFERENCE;
8959         wc->update_ref = update_ref;
8960         wc->keep_locks = 0;
8961         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
8962
8963         while (1) {
8964
8965                 ret = walk_down_tree(trans, root, path, wc);
8966                 if (ret < 0) {
8967                         err = ret;
8968                         break;
8969                 }
8970
8971                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8972                 if (ret < 0) {
8973                         err = ret;
8974                         break;
8975                 }
8976
8977                 if (ret > 0) {
8978                         BUG_ON(wc->stage != DROP_REFERENCE);
8979                         break;
8980                 }
8981
8982                 if (wc->stage == DROP_REFERENCE) {
8983                         level = wc->level;
8984                         btrfs_node_key(path->nodes[level],
8985                                        &root_item->drop_progress,
8986                                        path->slots[level]);
8987                         root_item->drop_level = level;
8988                 }
8989
8990                 BUG_ON(wc->level == 0);
8991                 if (btrfs_should_end_transaction(trans) ||
8992                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
8993                         ret = btrfs_update_root(trans, tree_root,
8994                                                 &root->root_key,
8995                                                 root_item);
8996                         if (ret) {
8997                                 btrfs_abort_transaction(trans, ret);
8998                                 err = ret;
8999                                 goto out_end_trans;
9000                         }
9001
9002                         btrfs_end_transaction_throttle(trans);
9003                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
9004                                 btrfs_debug(fs_info,
9005                                             "drop snapshot early exit");
9006                                 err = -EAGAIN;
9007                                 goto out_free;
9008                         }
9009
9010                         trans = btrfs_start_transaction(tree_root, 0);
9011                         if (IS_ERR(trans)) {
9012                                 err = PTR_ERR(trans);
9013                                 goto out_free;
9014                         }
9015                         if (block_rsv)
9016                                 trans->block_rsv = block_rsv;
9017                 }
9018         }
9019         btrfs_release_path(path);
9020         if (err)
9021                 goto out_end_trans;
9022
9023         ret = btrfs_del_root(trans, &root->root_key);
9024         if (ret) {
9025                 btrfs_abort_transaction(trans, ret);
9026                 err = ret;
9027                 goto out_end_trans;
9028         }
9029
9030         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9031                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9032                                       NULL, NULL);
9033                 if (ret < 0) {
9034                         btrfs_abort_transaction(trans, ret);
9035                         err = ret;
9036                         goto out_end_trans;
9037                 } else if (ret > 0) {
9038                         /* if we fail to delete the orphan item this time
9039                          * around, it'll get picked up the next time.
9040                          *
9041                          * The most common failure here is just -ENOENT.
9042                          */
9043                         btrfs_del_orphan_item(trans, tree_root,
9044                                               root->root_key.objectid);
9045                 }
9046         }
9047
9048         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9049                 btrfs_add_dropped_root(trans, root);
9050         } else {
9051                 free_extent_buffer(root->node);
9052                 free_extent_buffer(root->commit_root);
9053                 btrfs_put_fs_root(root);
9054         }
9055         root_dropped = true;
9056 out_end_trans:
9057         btrfs_end_transaction_throttle(trans);
9058 out_free:
9059         kfree(wc);
9060         btrfs_free_path(path);
9061 out:
9062         /*
9063          * So if we need to stop dropping the snapshot for whatever reason we
9064          * need to make sure to add it back to the dead root list so that we
9065          * keep trying to do the work later.  This also cleans up roots if we
9066          * don't have it in the radix (like when we recover after a power fail
9067          * or unmount) so we don't leak memory.
9068          */
9069         if (!for_reloc && !root_dropped)
9070                 btrfs_add_dead_root(root);
9071         if (err && err != -EAGAIN)
9072                 btrfs_handle_fs_error(fs_info, err, NULL);
9073         return err;
9074 }
9075
9076 /*
9077  * drop subtree rooted at tree block 'node'.
9078  *
9079  * NOTE: this function will unlock and release tree block 'node'
9080  * only used by relocation code
9081  */
9082 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9083                         struct btrfs_root *root,
9084                         struct extent_buffer *node,
9085                         struct extent_buffer *parent)
9086 {
9087         struct btrfs_fs_info *fs_info = root->fs_info;
9088         struct btrfs_path *path;
9089         struct walk_control *wc;
9090         int level;
9091         int parent_level;
9092         int ret = 0;
9093         int wret;
9094
9095         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9096
9097         path = btrfs_alloc_path();
9098         if (!path)
9099                 return -ENOMEM;
9100
9101         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9102         if (!wc) {
9103                 btrfs_free_path(path);
9104                 return -ENOMEM;
9105         }
9106
9107         btrfs_assert_tree_locked(parent);
9108         parent_level = btrfs_header_level(parent);
9109         extent_buffer_get(parent);
9110         path->nodes[parent_level] = parent;
9111         path->slots[parent_level] = btrfs_header_nritems(parent);
9112
9113         btrfs_assert_tree_locked(node);
9114         level = btrfs_header_level(node);
9115         path->nodes[level] = node;
9116         path->slots[level] = 0;
9117         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9118
9119         wc->refs[parent_level] = 1;
9120         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9121         wc->level = level;
9122         wc->shared_level = -1;
9123         wc->stage = DROP_REFERENCE;
9124         wc->update_ref = 0;
9125         wc->keep_locks = 1;
9126         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9127
9128         while (1) {
9129                 wret = walk_down_tree(trans, root, path, wc);
9130                 if (wret < 0) {
9131                         ret = wret;
9132                         break;
9133                 }
9134
9135                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9136                 if (wret < 0)
9137                         ret = wret;
9138                 if (wret != 0)
9139                         break;
9140         }
9141
9142         kfree(wc);
9143         btrfs_free_path(path);
9144         return ret;
9145 }
9146
9147 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
9148 {
9149         u64 num_devices;
9150         u64 stripped;
9151
9152         /*
9153          * if restripe for this chunk_type is on pick target profile and
9154          * return, otherwise do the usual balance
9155          */
9156         stripped = get_restripe_target(fs_info, flags);
9157         if (stripped)
9158                 return extended_to_chunk(stripped);
9159
9160         num_devices = fs_info->fs_devices->rw_devices;
9161
9162         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9163                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9164                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9165
9166         if (num_devices == 1) {
9167                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9168                 stripped = flags & ~stripped;
9169
9170                 /* turn raid0 into single device chunks */
9171                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9172                         return stripped;
9173
9174                 /* turn mirroring into duplication */
9175                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9176                              BTRFS_BLOCK_GROUP_RAID10))
9177                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9178         } else {
9179                 /* they already had raid on here, just return */
9180                 if (flags & stripped)
9181                         return flags;
9182
9183                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9184                 stripped = flags & ~stripped;
9185
9186                 /* switch duplicated blocks with raid1 */
9187                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9188                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9189
9190                 /* this is drive concat, leave it alone */
9191         }
9192
9193         return flags;
9194 }
9195
9196 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9197 {
9198         struct btrfs_space_info *sinfo = cache->space_info;
9199         u64 num_bytes;
9200         u64 min_allocable_bytes;
9201         int ret = -ENOSPC;
9202
9203         /*
9204          * We need some metadata space and system metadata space for
9205          * allocating chunks in some corner cases until we force to set
9206          * it to be readonly.
9207          */
9208         if ((sinfo->flags &
9209              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9210             !force)
9211                 min_allocable_bytes = SZ_1M;
9212         else
9213                 min_allocable_bytes = 0;
9214
9215         spin_lock(&sinfo->lock);
9216         spin_lock(&cache->lock);
9217
9218         if (cache->ro) {
9219                 cache->ro++;
9220                 ret = 0;
9221                 goto out;
9222         }
9223
9224         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9225                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9226
9227         if (btrfs_space_info_used(sinfo, true) + num_bytes +
9228             min_allocable_bytes <= sinfo->total_bytes) {
9229                 sinfo->bytes_readonly += num_bytes;
9230                 cache->ro++;
9231                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9232                 ret = 0;
9233         }
9234 out:
9235         spin_unlock(&cache->lock);
9236         spin_unlock(&sinfo->lock);
9237         return ret;
9238 }
9239
9240 int btrfs_inc_block_group_ro(struct btrfs_block_group_cache *cache)
9241
9242 {
9243         struct btrfs_fs_info *fs_info = cache->fs_info;
9244         struct btrfs_trans_handle *trans;
9245         u64 alloc_flags;
9246         int ret;
9247
9248 again:
9249         trans = btrfs_join_transaction(fs_info->extent_root);
9250         if (IS_ERR(trans))
9251                 return PTR_ERR(trans);
9252
9253         /*
9254          * we're not allowed to set block groups readonly after the dirty
9255          * block groups cache has started writing.  If it already started,
9256          * back off and let this transaction commit
9257          */
9258         mutex_lock(&fs_info->ro_block_group_mutex);
9259         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9260                 u64 transid = trans->transid;
9261
9262                 mutex_unlock(&fs_info->ro_block_group_mutex);
9263                 btrfs_end_transaction(trans);
9264
9265                 ret = btrfs_wait_for_commit(fs_info, transid);
9266                 if (ret)
9267                         return ret;
9268                 goto again;
9269         }
9270
9271         /*
9272          * if we are changing raid levels, try to allocate a corresponding
9273          * block group with the new raid level.
9274          */
9275         alloc_flags = update_block_group_flags(fs_info, cache->flags);
9276         if (alloc_flags != cache->flags) {
9277                 ret = do_chunk_alloc(trans, alloc_flags,
9278                                      CHUNK_ALLOC_FORCE);
9279                 /*
9280                  * ENOSPC is allowed here, we may have enough space
9281                  * already allocated at the new raid level to
9282                  * carry on
9283                  */
9284                 if (ret == -ENOSPC)
9285                         ret = 0;
9286                 if (ret < 0)
9287                         goto out;
9288         }
9289
9290         ret = inc_block_group_ro(cache, 0);
9291         if (!ret)
9292                 goto out;
9293         alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
9294         ret = do_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
9295         if (ret < 0)
9296                 goto out;
9297         ret = inc_block_group_ro(cache, 0);
9298 out:
9299         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9300                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
9301                 mutex_lock(&fs_info->chunk_mutex);
9302                 check_system_chunk(trans, alloc_flags);
9303                 mutex_unlock(&fs_info->chunk_mutex);
9304         }
9305         mutex_unlock(&fs_info->ro_block_group_mutex);
9306
9307         btrfs_end_transaction(trans);
9308         return ret;
9309 }
9310
9311 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
9312 {
9313         u64 alloc_flags = get_alloc_profile(trans->fs_info, type);
9314
9315         return do_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
9316 }
9317
9318 /*
9319  * helper to account the unused space of all the readonly block group in the
9320  * space_info. takes mirrors into account.
9321  */
9322 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9323 {
9324         struct btrfs_block_group_cache *block_group;
9325         u64 free_bytes = 0;
9326         int factor;
9327
9328         /* It's df, we don't care if it's racy */
9329         if (list_empty(&sinfo->ro_bgs))
9330                 return 0;
9331
9332         spin_lock(&sinfo->lock);
9333         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9334                 spin_lock(&block_group->lock);
9335
9336                 if (!block_group->ro) {
9337                         spin_unlock(&block_group->lock);
9338                         continue;
9339                 }
9340
9341                 factor = btrfs_bg_type_to_factor(block_group->flags);
9342                 free_bytes += (block_group->key.offset -
9343                                btrfs_block_group_used(&block_group->item)) *
9344                                factor;
9345
9346                 spin_unlock(&block_group->lock);
9347         }
9348         spin_unlock(&sinfo->lock);
9349
9350         return free_bytes;
9351 }
9352
9353 void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
9354 {
9355         struct btrfs_space_info *sinfo = cache->space_info;
9356         u64 num_bytes;
9357
9358         BUG_ON(!cache->ro);
9359
9360         spin_lock(&sinfo->lock);
9361         spin_lock(&cache->lock);
9362         if (!--cache->ro) {
9363                 num_bytes = cache->key.offset - cache->reserved -
9364                             cache->pinned - cache->bytes_super -
9365                             btrfs_block_group_used(&cache->item);
9366                 sinfo->bytes_readonly -= num_bytes;
9367                 list_del_init(&cache->ro_list);
9368         }
9369         spin_unlock(&cache->lock);
9370         spin_unlock(&sinfo->lock);
9371 }
9372
9373 /*
9374  * checks to see if its even possible to relocate this block group.
9375  *
9376  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9377  * ok to go ahead and try.
9378  */
9379 int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
9380 {
9381         struct btrfs_root *root = fs_info->extent_root;
9382         struct btrfs_block_group_cache *block_group;
9383         struct btrfs_space_info *space_info;
9384         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
9385         struct btrfs_device *device;
9386         struct btrfs_trans_handle *trans;
9387         u64 min_free;
9388         u64 dev_min = 1;
9389         u64 dev_nr = 0;
9390         u64 target;
9391         int debug;
9392         int index;
9393         int full = 0;
9394         int ret = 0;
9395
9396         debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG);
9397
9398         block_group = btrfs_lookup_block_group(fs_info, bytenr);
9399
9400         /* odd, couldn't find the block group, leave it alone */
9401         if (!block_group) {
9402                 if (debug)
9403                         btrfs_warn(fs_info,
9404                                    "can't find block group for bytenr %llu",
9405                                    bytenr);
9406                 return -1;
9407         }
9408
9409         min_free = btrfs_block_group_used(&block_group->item);
9410
9411         /* no bytes used, we're good */
9412         if (!min_free)
9413                 goto out;
9414
9415         space_info = block_group->space_info;
9416         spin_lock(&space_info->lock);
9417
9418         full = space_info->full;
9419
9420         /*
9421          * if this is the last block group we have in this space, we can't
9422          * relocate it unless we're able to allocate a new chunk below.
9423          *
9424          * Otherwise, we need to make sure we have room in the space to handle
9425          * all of the extents from this block group.  If we can, we're good
9426          */
9427         if ((space_info->total_bytes != block_group->key.offset) &&
9428             (btrfs_space_info_used(space_info, false) + min_free <
9429              space_info->total_bytes)) {
9430                 spin_unlock(&space_info->lock);
9431                 goto out;
9432         }
9433         spin_unlock(&space_info->lock);
9434
9435         /*
9436          * ok we don't have enough space, but maybe we have free space on our
9437          * devices to allocate new chunks for relocation, so loop through our
9438          * alloc devices and guess if we have enough space.  if this block
9439          * group is going to be restriped, run checks against the target
9440          * profile instead of the current one.
9441          */
9442         ret = -1;
9443
9444         /*
9445          * index:
9446          *      0: raid10
9447          *      1: raid1
9448          *      2: dup
9449          *      3: raid0
9450          *      4: single
9451          */
9452         target = get_restripe_target(fs_info, block_group->flags);
9453         if (target) {
9454                 index = btrfs_bg_flags_to_raid_index(extended_to_chunk(target));
9455         } else {
9456                 /*
9457                  * this is just a balance, so if we were marked as full
9458                  * we know there is no space for a new chunk
9459                  */
9460                 if (full) {
9461                         if (debug)
9462                                 btrfs_warn(fs_info,
9463                                            "no space to alloc new chunk for block group %llu",
9464                                            block_group->key.objectid);
9465                         goto out;
9466                 }
9467
9468                 index = btrfs_bg_flags_to_raid_index(block_group->flags);
9469         }
9470
9471         if (index == BTRFS_RAID_RAID10) {
9472                 dev_min = 4;
9473                 /* Divide by 2 */
9474                 min_free >>= 1;
9475         } else if (index == BTRFS_RAID_RAID1) {
9476                 dev_min = 2;
9477         } else if (index == BTRFS_RAID_DUP) {
9478                 /* Multiply by 2 */
9479                 min_free <<= 1;
9480         } else if (index == BTRFS_RAID_RAID0) {
9481                 dev_min = fs_devices->rw_devices;
9482                 min_free = div64_u64(min_free, dev_min);
9483         }
9484
9485         /* We need to do this so that we can look at pending chunks */
9486         trans = btrfs_join_transaction(root);
9487         if (IS_ERR(trans)) {
9488                 ret = PTR_ERR(trans);
9489                 goto out;
9490         }
9491
9492         mutex_lock(&fs_info->chunk_mutex);
9493         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9494                 u64 dev_offset;
9495
9496                 /*
9497                  * check to make sure we can actually find a chunk with enough
9498                  * space to fit our block group in.
9499                  */
9500                 if (device->total_bytes > device->bytes_used + min_free &&
9501                     !test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
9502                         ret = find_free_dev_extent(trans, device, min_free,
9503                                                    &dev_offset, NULL);
9504                         if (!ret)
9505                                 dev_nr++;
9506
9507                         if (dev_nr >= dev_min)
9508                                 break;
9509
9510                         ret = -1;
9511                 }
9512         }
9513         if (debug && ret == -1)
9514                 btrfs_warn(fs_info,
9515                            "no space to allocate a new chunk for block group %llu",
9516                            block_group->key.objectid);
9517         mutex_unlock(&fs_info->chunk_mutex);
9518         btrfs_end_transaction(trans);
9519 out:
9520         btrfs_put_block_group(block_group);
9521         return ret;
9522 }
9523
9524 static int find_first_block_group(struct btrfs_fs_info *fs_info,
9525                                   struct btrfs_path *path,
9526                                   struct btrfs_key *key)
9527 {
9528         struct btrfs_root *root = fs_info->extent_root;
9529         int ret = 0;
9530         struct btrfs_key found_key;
9531         struct extent_buffer *leaf;
9532         struct btrfs_block_group_item bg;
9533         u64 flags;
9534         int slot;
9535
9536         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9537         if (ret < 0)
9538                 goto out;
9539
9540         while (1) {
9541                 slot = path->slots[0];
9542                 leaf = path->nodes[0];
9543                 if (slot >= btrfs_header_nritems(leaf)) {
9544                         ret = btrfs_next_leaf(root, path);
9545                         if (ret == 0)
9546                                 continue;
9547                         if (ret < 0)
9548                                 goto out;
9549                         break;
9550                 }
9551                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9552
9553                 if (found_key.objectid >= key->objectid &&
9554                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9555                         struct extent_map_tree *em_tree;
9556                         struct extent_map *em;
9557
9558                         em_tree = &root->fs_info->mapping_tree.map_tree;
9559                         read_lock(&em_tree->lock);
9560                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9561                                                    found_key.offset);
9562                         read_unlock(&em_tree->lock);
9563                         if (!em) {
9564                                 btrfs_err(fs_info,
9565                         "logical %llu len %llu found bg but no related chunk",
9566                                           found_key.objectid, found_key.offset);
9567                                 ret = -ENOENT;
9568                         } else if (em->start != found_key.objectid ||
9569                                    em->len != found_key.offset) {
9570                                 btrfs_err(fs_info,
9571                 "block group %llu len %llu mismatch with chunk %llu len %llu",
9572                                           found_key.objectid, found_key.offset,
9573                                           em->start, em->len);
9574                                 ret = -EUCLEAN;
9575                         } else {
9576                                 read_extent_buffer(leaf, &bg,
9577                                         btrfs_item_ptr_offset(leaf, slot),
9578                                         sizeof(bg));
9579                                 flags = btrfs_block_group_flags(&bg) &
9580                                         BTRFS_BLOCK_GROUP_TYPE_MASK;
9581
9582                                 if (flags != (em->map_lookup->type &
9583                                               BTRFS_BLOCK_GROUP_TYPE_MASK)) {
9584                                         btrfs_err(fs_info,
9585 "block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
9586                                                 found_key.objectid,
9587                                                 found_key.offset, flags,
9588                                                 (BTRFS_BLOCK_GROUP_TYPE_MASK &
9589                                                  em->map_lookup->type));
9590                                         ret = -EUCLEAN;
9591                                 } else {
9592                                         ret = 0;
9593                                 }
9594                         }
9595                         free_extent_map(em);
9596                         goto out;
9597                 }
9598                 path->slots[0]++;
9599         }
9600 out:
9601         return ret;
9602 }
9603
9604 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9605 {
9606         struct btrfs_block_group_cache *block_group;
9607         u64 last = 0;
9608
9609         while (1) {
9610                 struct inode *inode;
9611
9612                 block_group = btrfs_lookup_first_block_group(info, last);
9613                 while (block_group) {
9614                         spin_lock(&block_group->lock);
9615                         if (block_group->iref)
9616                                 break;
9617                         spin_unlock(&block_group->lock);
9618                         block_group = next_block_group(info, block_group);
9619                 }
9620                 if (!block_group) {
9621                         if (last == 0)
9622                                 break;
9623                         last = 0;
9624                         continue;
9625                 }
9626
9627                 inode = block_group->inode;
9628                 block_group->iref = 0;
9629                 block_group->inode = NULL;
9630                 spin_unlock(&block_group->lock);
9631                 ASSERT(block_group->io_ctl.inode == NULL);
9632                 iput(inode);
9633                 last = block_group->key.objectid + block_group->key.offset;
9634                 btrfs_put_block_group(block_group);
9635         }
9636 }
9637
9638 /*
9639  * Must be called only after stopping all workers, since we could have block
9640  * group caching kthreads running, and therefore they could race with us if we
9641  * freed the block groups before stopping them.
9642  */
9643 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9644 {
9645         struct btrfs_block_group_cache *block_group;
9646         struct btrfs_space_info *space_info;
9647         struct btrfs_caching_control *caching_ctl;
9648         struct rb_node *n;
9649
9650         down_write(&info->commit_root_sem);
9651         while (!list_empty(&info->caching_block_groups)) {
9652                 caching_ctl = list_entry(info->caching_block_groups.next,
9653                                          struct btrfs_caching_control, list);
9654                 list_del(&caching_ctl->list);
9655                 put_caching_control(caching_ctl);
9656         }
9657         up_write(&info->commit_root_sem);
9658
9659         spin_lock(&info->unused_bgs_lock);
9660         while (!list_empty(&info->unused_bgs)) {
9661                 block_group = list_first_entry(&info->unused_bgs,
9662                                                struct btrfs_block_group_cache,
9663                                                bg_list);
9664                 list_del_init(&block_group->bg_list);
9665                 btrfs_put_block_group(block_group);
9666         }
9667         spin_unlock(&info->unused_bgs_lock);
9668
9669         spin_lock(&info->block_group_cache_lock);
9670         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9671                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9672                                        cache_node);
9673                 rb_erase(&block_group->cache_node,
9674                          &info->block_group_cache_tree);
9675                 RB_CLEAR_NODE(&block_group->cache_node);
9676                 spin_unlock(&info->block_group_cache_lock);
9677
9678                 down_write(&block_group->space_info->groups_sem);
9679                 list_del(&block_group->list);
9680                 up_write(&block_group->space_info->groups_sem);
9681
9682                 /*
9683                  * We haven't cached this block group, which means we could
9684                  * possibly have excluded extents on this block group.
9685                  */
9686                 if (block_group->cached == BTRFS_CACHE_NO ||
9687                     block_group->cached == BTRFS_CACHE_ERROR)
9688                         free_excluded_extents(block_group);
9689
9690                 btrfs_remove_free_space_cache(block_group);
9691                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
9692                 ASSERT(list_empty(&block_group->dirty_list));
9693                 ASSERT(list_empty(&block_group->io_list));
9694                 ASSERT(list_empty(&block_group->bg_list));
9695                 ASSERT(atomic_read(&block_group->count) == 1);
9696                 btrfs_put_block_group(block_group);
9697
9698                 spin_lock(&info->block_group_cache_lock);
9699         }
9700         spin_unlock(&info->block_group_cache_lock);
9701
9702         /* now that all the block groups are freed, go through and
9703          * free all the space_info structs.  This is only called during
9704          * the final stages of unmount, and so we know nobody is
9705          * using them.  We call synchronize_rcu() once before we start,
9706          * just to be on the safe side.
9707          */
9708         synchronize_rcu();
9709
9710         release_global_block_rsv(info);
9711
9712         while (!list_empty(&info->space_info)) {
9713                 int i;
9714
9715                 space_info = list_entry(info->space_info.next,
9716                                         struct btrfs_space_info,
9717                                         list);
9718
9719                 /*
9720                  * Do not hide this behind enospc_debug, this is actually
9721                  * important and indicates a real bug if this happens.
9722                  */
9723                 if (WARN_ON(space_info->bytes_pinned > 0 ||
9724                             space_info->bytes_reserved > 0 ||
9725                             space_info->bytes_may_use > 0))
9726                         dump_space_info(info, space_info, 0, 0);
9727                 list_del(&space_info->list);
9728                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9729                         struct kobject *kobj;
9730                         kobj = space_info->block_group_kobjs[i];
9731                         space_info->block_group_kobjs[i] = NULL;
9732                         if (kobj) {
9733                                 kobject_del(kobj);
9734                                 kobject_put(kobj);
9735                         }
9736                 }
9737                 kobject_del(&space_info->kobj);
9738                 kobject_put(&space_info->kobj);
9739         }
9740         return 0;
9741 }
9742
9743 /* link_block_group will queue up kobjects to add when we're reclaim-safe */
9744 void btrfs_add_raid_kobjects(struct btrfs_fs_info *fs_info)
9745 {
9746         struct btrfs_space_info *space_info;
9747         struct raid_kobject *rkobj;
9748         LIST_HEAD(list);
9749         int index;
9750         int ret = 0;
9751
9752         spin_lock(&fs_info->pending_raid_kobjs_lock);
9753         list_splice_init(&fs_info->pending_raid_kobjs, &list);
9754         spin_unlock(&fs_info->pending_raid_kobjs_lock);
9755
9756         list_for_each_entry(rkobj, &list, list) {
9757                 space_info = __find_space_info(fs_info, rkobj->flags);
9758                 index = btrfs_bg_flags_to_raid_index(rkobj->flags);
9759
9760                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9761                                   "%s", get_raid_name(index));
9762                 if (ret) {
9763                         kobject_put(&rkobj->kobj);
9764                         break;
9765                 }
9766         }
9767         if (ret)
9768                 btrfs_warn(fs_info,
9769                            "failed to add kobject for block cache, ignoring");
9770 }
9771
9772 static void link_block_group(struct btrfs_block_group_cache *cache)
9773 {
9774         struct btrfs_space_info *space_info = cache->space_info;
9775         struct btrfs_fs_info *fs_info = cache->fs_info;
9776         int index = btrfs_bg_flags_to_raid_index(cache->flags);
9777         bool first = false;
9778
9779         down_write(&space_info->groups_sem);
9780         if (list_empty(&space_info->block_groups[index]))
9781                 first = true;
9782         list_add_tail(&cache->list, &space_info->block_groups[index]);
9783         up_write(&space_info->groups_sem);
9784
9785         if (first) {
9786                 struct raid_kobject *rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9787                 if (!rkobj) {
9788                         btrfs_warn(cache->fs_info,
9789                                 "couldn't alloc memory for raid level kobject");
9790                         return;
9791                 }
9792                 rkobj->flags = cache->flags;
9793                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9794
9795                 spin_lock(&fs_info->pending_raid_kobjs_lock);
9796                 list_add_tail(&rkobj->list, &fs_info->pending_raid_kobjs);
9797                 spin_unlock(&fs_info->pending_raid_kobjs_lock);
9798                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9799         }
9800 }
9801
9802 static struct btrfs_block_group_cache *
9803 btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
9804                                u64 start, u64 size)
9805 {
9806         struct btrfs_block_group_cache *cache;
9807
9808         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9809         if (!cache)
9810                 return NULL;
9811
9812         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9813                                         GFP_NOFS);
9814         if (!cache->free_space_ctl) {
9815                 kfree(cache);
9816                 return NULL;
9817         }
9818
9819         cache->key.objectid = start;
9820         cache->key.offset = size;
9821         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9822
9823         cache->fs_info = fs_info;
9824         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
9825         set_free_space_tree_thresholds(cache);
9826
9827         atomic_set(&cache->count, 1);
9828         spin_lock_init(&cache->lock);
9829         init_rwsem(&cache->data_rwsem);
9830         INIT_LIST_HEAD(&cache->list);
9831         INIT_LIST_HEAD(&cache->cluster_list);
9832         INIT_LIST_HEAD(&cache->bg_list);
9833         INIT_LIST_HEAD(&cache->ro_list);
9834         INIT_LIST_HEAD(&cache->dirty_list);
9835         INIT_LIST_HEAD(&cache->io_list);
9836         btrfs_init_free_space_ctl(cache);
9837         atomic_set(&cache->trimming, 0);
9838         mutex_init(&cache->free_space_lock);
9839         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
9840
9841         return cache;
9842 }
9843
9844
9845 /*
9846  * Iterate all chunks and verify that each of them has the corresponding block
9847  * group
9848  */
9849 static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
9850 {
9851         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
9852         struct extent_map *em;
9853         struct btrfs_block_group_cache *bg;
9854         u64 start = 0;
9855         int ret = 0;
9856
9857         while (1) {
9858                 read_lock(&map_tree->map_tree.lock);
9859                 /*
9860                  * lookup_extent_mapping will return the first extent map
9861                  * intersecting the range, so setting @len to 1 is enough to
9862                  * get the first chunk.
9863                  */
9864                 em = lookup_extent_mapping(&map_tree->map_tree, start, 1);
9865                 read_unlock(&map_tree->map_tree.lock);
9866                 if (!em)
9867                         break;
9868
9869                 bg = btrfs_lookup_block_group(fs_info, em->start);
9870                 if (!bg) {
9871                         btrfs_err(fs_info,
9872         "chunk start=%llu len=%llu doesn't have corresponding block group",
9873                                      em->start, em->len);
9874                         ret = -EUCLEAN;
9875                         free_extent_map(em);
9876                         break;
9877                 }
9878                 if (bg->key.objectid != em->start ||
9879                     bg->key.offset != em->len ||
9880                     (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
9881                     (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
9882                         btrfs_err(fs_info,
9883 "chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
9884                                 em->start, em->len,
9885                                 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
9886                                 bg->key.objectid, bg->key.offset,
9887                                 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
9888                         ret = -EUCLEAN;
9889                         free_extent_map(em);
9890                         btrfs_put_block_group(bg);
9891                         break;
9892                 }
9893                 start = em->start + em->len;
9894                 free_extent_map(em);
9895                 btrfs_put_block_group(bg);
9896         }
9897         return ret;
9898 }
9899
9900 int btrfs_read_block_groups(struct btrfs_fs_info *info)
9901 {
9902         struct btrfs_path *path;
9903         int ret;
9904         struct btrfs_block_group_cache *cache;
9905         struct btrfs_space_info *space_info;
9906         struct btrfs_key key;
9907         struct btrfs_key found_key;
9908         struct extent_buffer *leaf;
9909         int need_clear = 0;
9910         u64 cache_gen;
9911         u64 feature;
9912         int mixed;
9913
9914         feature = btrfs_super_incompat_flags(info->super_copy);
9915         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
9916
9917         key.objectid = 0;
9918         key.offset = 0;
9919         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9920         path = btrfs_alloc_path();
9921         if (!path)
9922                 return -ENOMEM;
9923         path->reada = READA_FORWARD;
9924
9925         cache_gen = btrfs_super_cache_generation(info->super_copy);
9926         if (btrfs_test_opt(info, SPACE_CACHE) &&
9927             btrfs_super_generation(info->super_copy) != cache_gen)
9928                 need_clear = 1;
9929         if (btrfs_test_opt(info, CLEAR_CACHE))
9930                 need_clear = 1;
9931
9932         while (1) {
9933                 ret = find_first_block_group(info, path, &key);
9934                 if (ret > 0)
9935                         break;
9936                 if (ret != 0)
9937                         goto error;
9938
9939                 leaf = path->nodes[0];
9940                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9941
9942                 cache = btrfs_create_block_group_cache(info, found_key.objectid,
9943                                                        found_key.offset);
9944                 if (!cache) {
9945                         ret = -ENOMEM;
9946                         goto error;
9947                 }
9948
9949                 if (need_clear) {
9950                         /*
9951                          * When we mount with old space cache, we need to
9952                          * set BTRFS_DC_CLEAR and set dirty flag.
9953                          *
9954                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9955                          *    truncate the old free space cache inode and
9956                          *    setup a new one.
9957                          * b) Setting 'dirty flag' makes sure that we flush
9958                          *    the new space cache info onto disk.
9959                          */
9960                         if (btrfs_test_opt(info, SPACE_CACHE))
9961                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9962                 }
9963
9964                 read_extent_buffer(leaf, &cache->item,
9965                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9966                                    sizeof(cache->item));
9967                 cache->flags = btrfs_block_group_flags(&cache->item);
9968                 if (!mixed &&
9969                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
9970                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
9971                         btrfs_err(info,
9972 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
9973                                   cache->key.objectid);
9974                         ret = -EINVAL;
9975                         goto error;
9976                 }
9977
9978                 key.objectid = found_key.objectid + found_key.offset;
9979                 btrfs_release_path(path);
9980
9981                 /*
9982                  * We need to exclude the super stripes now so that the space
9983                  * info has super bytes accounted for, otherwise we'll think
9984                  * we have more space than we actually do.
9985                  */
9986                 ret = exclude_super_stripes(cache);
9987                 if (ret) {
9988                         /*
9989                          * We may have excluded something, so call this just in
9990                          * case.
9991                          */
9992                         free_excluded_extents(cache);
9993                         btrfs_put_block_group(cache);
9994                         goto error;
9995                 }
9996
9997                 /*
9998                  * check for two cases, either we are full, and therefore
9999                  * don't need to bother with the caching work since we won't
10000                  * find any space, or we are empty, and we can just add all
10001                  * the space in and be done with it.  This saves us _alot_ of
10002                  * time, particularly in the full case.
10003                  */
10004                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10005                         cache->last_byte_to_unpin = (u64)-1;
10006                         cache->cached = BTRFS_CACHE_FINISHED;
10007                         free_excluded_extents(cache);
10008                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10009                         cache->last_byte_to_unpin = (u64)-1;
10010                         cache->cached = BTRFS_CACHE_FINISHED;
10011                         add_new_free_space(cache, found_key.objectid,
10012                                            found_key.objectid +
10013                                            found_key.offset);
10014                         free_excluded_extents(cache);
10015                 }
10016
10017                 ret = btrfs_add_block_group_cache(info, cache);
10018                 if (ret) {
10019                         btrfs_remove_free_space_cache(cache);
10020                         btrfs_put_block_group(cache);
10021                         goto error;
10022                 }
10023
10024                 trace_btrfs_add_block_group(info, cache, 0);
10025                 update_space_info(info, cache->flags, found_key.offset,
10026                                   btrfs_block_group_used(&cache->item),
10027                                   cache->bytes_super, &space_info);
10028
10029                 cache->space_info = space_info;
10030
10031                 link_block_group(cache);
10032
10033                 set_avail_alloc_bits(info, cache->flags);
10034                 if (btrfs_chunk_readonly(info, cache->key.objectid)) {
10035                         inc_block_group_ro(cache, 1);
10036                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10037                         ASSERT(list_empty(&cache->bg_list));
10038                         btrfs_mark_bg_unused(cache);
10039                 }
10040         }
10041
10042         list_for_each_entry_rcu(space_info, &info->space_info, list) {
10043                 if (!(get_alloc_profile(info, space_info->flags) &
10044                       (BTRFS_BLOCK_GROUP_RAID10 |
10045                        BTRFS_BLOCK_GROUP_RAID1 |
10046                        BTRFS_BLOCK_GROUP_RAID5 |
10047                        BTRFS_BLOCK_GROUP_RAID6 |
10048                        BTRFS_BLOCK_GROUP_DUP)))
10049                         continue;
10050                 /*
10051                  * avoid allocating from un-mirrored block group if there are
10052                  * mirrored block groups.
10053                  */
10054                 list_for_each_entry(cache,
10055                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10056                                 list)
10057                         inc_block_group_ro(cache, 1);
10058                 list_for_each_entry(cache,
10059                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10060                                 list)
10061                         inc_block_group_ro(cache, 1);
10062         }
10063
10064         btrfs_add_raid_kobjects(info);
10065         init_global_block_rsv(info);
10066         ret = check_chunk_block_group_mappings(info);
10067 error:
10068         btrfs_free_path(path);
10069         return ret;
10070 }
10071
10072 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
10073 {
10074         struct btrfs_fs_info *fs_info = trans->fs_info;
10075         struct btrfs_block_group_cache *block_group, *tmp;
10076         struct btrfs_root *extent_root = fs_info->extent_root;
10077         struct btrfs_block_group_item item;
10078         struct btrfs_key key;
10079         int ret = 0;
10080         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10081
10082         trans->can_flush_pending_bgs = false;
10083         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10084                 if (ret)
10085                         goto next;
10086
10087                 spin_lock(&block_group->lock);
10088                 memcpy(&item, &block_group->item, sizeof(item));
10089                 memcpy(&key, &block_group->key, sizeof(key));
10090                 spin_unlock(&block_group->lock);
10091
10092                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10093                                         sizeof(item));
10094                 if (ret)
10095                         btrfs_abort_transaction(trans, ret);
10096                 ret = btrfs_finish_chunk_alloc(trans, key.objectid, key.offset);
10097                 if (ret)
10098                         btrfs_abort_transaction(trans, ret);
10099                 add_block_group_free_space(trans, block_group);
10100                 /* already aborted the transaction if it failed. */
10101 next:
10102                 list_del_init(&block_group->bg_list);
10103         }
10104         trans->can_flush_pending_bgs = can_flush_pending_bgs;
10105 }
10106
10107 int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
10108                            u64 type, u64 chunk_offset, u64 size)
10109 {
10110         struct btrfs_fs_info *fs_info = trans->fs_info;
10111         struct btrfs_block_group_cache *cache;
10112         int ret;
10113
10114         btrfs_set_log_full_commit(fs_info, trans);
10115
10116         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
10117         if (!cache)
10118                 return -ENOMEM;
10119
10120         btrfs_set_block_group_used(&cache->item, bytes_used);
10121         btrfs_set_block_group_chunk_objectid(&cache->item,
10122                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID);
10123         btrfs_set_block_group_flags(&cache->item, type);
10124
10125         cache->flags = type;
10126         cache->last_byte_to_unpin = (u64)-1;
10127         cache->cached = BTRFS_CACHE_FINISHED;
10128         cache->needs_free_space = 1;
10129         ret = exclude_super_stripes(cache);
10130         if (ret) {
10131                 /*
10132                  * We may have excluded something, so call this just in
10133                  * case.
10134                  */
10135                 free_excluded_extents(cache);
10136                 btrfs_put_block_group(cache);
10137                 return ret;
10138         }
10139
10140         add_new_free_space(cache, chunk_offset, chunk_offset + size);
10141
10142         free_excluded_extents(cache);
10143
10144 #ifdef CONFIG_BTRFS_DEBUG
10145         if (btrfs_should_fragment_free_space(cache)) {
10146                 u64 new_bytes_used = size - bytes_used;
10147
10148                 bytes_used += new_bytes_used >> 1;
10149                 fragment_free_space(cache);
10150         }
10151 #endif
10152         /*
10153          * Ensure the corresponding space_info object is created and
10154          * assigned to our block group. We want our bg to be added to the rbtree
10155          * with its ->space_info set.
10156          */
10157         cache->space_info = __find_space_info(fs_info, cache->flags);
10158         ASSERT(cache->space_info);
10159
10160         ret = btrfs_add_block_group_cache(fs_info, cache);
10161         if (ret) {
10162                 btrfs_remove_free_space_cache(cache);
10163                 btrfs_put_block_group(cache);
10164                 return ret;
10165         }
10166
10167         /*
10168          * Now that our block group has its ->space_info set and is inserted in
10169          * the rbtree, update the space info's counters.
10170          */
10171         trace_btrfs_add_block_group(fs_info, cache, 1);
10172         update_space_info(fs_info, cache->flags, size, bytes_used,
10173                                 cache->bytes_super, &cache->space_info);
10174         update_global_block_rsv(fs_info);
10175
10176         link_block_group(cache);
10177
10178         list_add_tail(&cache->bg_list, &trans->new_bgs);
10179
10180         set_avail_alloc_bits(fs_info, type);
10181         return 0;
10182 }
10183
10184 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10185 {
10186         u64 extra_flags = chunk_to_extended(flags) &
10187                                 BTRFS_EXTENDED_PROFILE_MASK;
10188
10189         write_seqlock(&fs_info->profiles_lock);
10190         if (flags & BTRFS_BLOCK_GROUP_DATA)
10191                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10192         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10193                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10194         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10195                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10196         write_sequnlock(&fs_info->profiles_lock);
10197 }
10198
10199 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10200                              u64 group_start, struct extent_map *em)
10201 {
10202         struct btrfs_fs_info *fs_info = trans->fs_info;
10203         struct btrfs_root *root = fs_info->extent_root;
10204         struct btrfs_path *path;
10205         struct btrfs_block_group_cache *block_group;
10206         struct btrfs_free_cluster *cluster;
10207         struct btrfs_root *tree_root = fs_info->tree_root;
10208         struct btrfs_key key;
10209         struct inode *inode;
10210         struct kobject *kobj = NULL;
10211         int ret;
10212         int index;
10213         int factor;
10214         struct btrfs_caching_control *caching_ctl = NULL;
10215         bool remove_em;
10216
10217         block_group = btrfs_lookup_block_group(fs_info, group_start);
10218         BUG_ON(!block_group);
10219         BUG_ON(!block_group->ro);
10220
10221         trace_btrfs_remove_block_group(block_group);
10222         /*
10223          * Free the reserved super bytes from this block group before
10224          * remove it.
10225          */
10226         free_excluded_extents(block_group);
10227         btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
10228                                   block_group->key.offset);
10229
10230         memcpy(&key, &block_group->key, sizeof(key));
10231         index = btrfs_bg_flags_to_raid_index(block_group->flags);
10232         factor = btrfs_bg_type_to_factor(block_group->flags);
10233
10234         /* make sure this block group isn't part of an allocation cluster */
10235         cluster = &fs_info->data_alloc_cluster;
10236         spin_lock(&cluster->refill_lock);
10237         btrfs_return_cluster_to_free_space(block_group, cluster);
10238         spin_unlock(&cluster->refill_lock);
10239
10240         /*
10241          * make sure this block group isn't part of a metadata
10242          * allocation cluster
10243          */
10244         cluster = &fs_info->meta_alloc_cluster;
10245         spin_lock(&cluster->refill_lock);
10246         btrfs_return_cluster_to_free_space(block_group, cluster);
10247         spin_unlock(&cluster->refill_lock);
10248
10249         path = btrfs_alloc_path();
10250         if (!path) {
10251                 ret = -ENOMEM;
10252                 goto out;
10253         }
10254
10255         /*
10256          * get the inode first so any iput calls done for the io_list
10257          * aren't the final iput (no unlinks allowed now)
10258          */
10259         inode = lookup_free_space_inode(fs_info, block_group, path);
10260
10261         mutex_lock(&trans->transaction->cache_write_mutex);
10262         /*
10263          * make sure our free spache cache IO is done before remove the
10264          * free space inode
10265          */
10266         spin_lock(&trans->transaction->dirty_bgs_lock);
10267         if (!list_empty(&block_group->io_list)) {
10268                 list_del_init(&block_group->io_list);
10269
10270                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10271
10272                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10273                 btrfs_wait_cache_io(trans, block_group, path);
10274                 btrfs_put_block_group(block_group);
10275                 spin_lock(&trans->transaction->dirty_bgs_lock);
10276         }
10277
10278         if (!list_empty(&block_group->dirty_list)) {
10279                 list_del_init(&block_group->dirty_list);
10280                 btrfs_put_block_group(block_group);
10281         }
10282         spin_unlock(&trans->transaction->dirty_bgs_lock);
10283         mutex_unlock(&trans->transaction->cache_write_mutex);
10284
10285         if (!IS_ERR(inode)) {
10286                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10287                 if (ret) {
10288                         btrfs_add_delayed_iput(inode);
10289                         goto out;
10290                 }
10291                 clear_nlink(inode);
10292                 /* One for the block groups ref */
10293                 spin_lock(&block_group->lock);
10294                 if (block_group->iref) {
10295                         block_group->iref = 0;
10296                         block_group->inode = NULL;
10297                         spin_unlock(&block_group->lock);
10298                         iput(inode);
10299                 } else {
10300                         spin_unlock(&block_group->lock);
10301                 }
10302                 /* One for our lookup ref */
10303                 btrfs_add_delayed_iput(inode);
10304         }
10305
10306         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10307         key.offset = block_group->key.objectid;
10308         key.type = 0;
10309
10310         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10311         if (ret < 0)
10312                 goto out;
10313         if (ret > 0)
10314                 btrfs_release_path(path);
10315         if (ret == 0) {
10316                 ret = btrfs_del_item(trans, tree_root, path);
10317                 if (ret)
10318                         goto out;
10319                 btrfs_release_path(path);
10320         }
10321
10322         spin_lock(&fs_info->block_group_cache_lock);
10323         rb_erase(&block_group->cache_node,
10324                  &fs_info->block_group_cache_tree);
10325         RB_CLEAR_NODE(&block_group->cache_node);
10326
10327         if (fs_info->first_logical_byte == block_group->key.objectid)
10328                 fs_info->first_logical_byte = (u64)-1;
10329         spin_unlock(&fs_info->block_group_cache_lock);
10330
10331         down_write(&block_group->space_info->groups_sem);
10332         /*
10333          * we must use list_del_init so people can check to see if they
10334          * are still on the list after taking the semaphore
10335          */
10336         list_del_init(&block_group->list);
10337         if (list_empty(&block_group->space_info->block_groups[index])) {
10338                 kobj = block_group->space_info->block_group_kobjs[index];
10339                 block_group->space_info->block_group_kobjs[index] = NULL;
10340                 clear_avail_alloc_bits(fs_info, block_group->flags);
10341         }
10342         up_write(&block_group->space_info->groups_sem);
10343         if (kobj) {
10344                 kobject_del(kobj);
10345                 kobject_put(kobj);
10346         }
10347
10348         if (block_group->has_caching_ctl)
10349                 caching_ctl = get_caching_control(block_group);
10350         if (block_group->cached == BTRFS_CACHE_STARTED)
10351                 wait_block_group_cache_done(block_group);
10352         if (block_group->has_caching_ctl) {
10353                 down_write(&fs_info->commit_root_sem);
10354                 if (!caching_ctl) {
10355                         struct btrfs_caching_control *ctl;
10356
10357                         list_for_each_entry(ctl,
10358                                     &fs_info->caching_block_groups, list)
10359                                 if (ctl->block_group == block_group) {
10360                                         caching_ctl = ctl;
10361                                         refcount_inc(&caching_ctl->count);
10362                                         break;
10363                                 }
10364                 }
10365                 if (caching_ctl)
10366                         list_del_init(&caching_ctl->list);
10367                 up_write(&fs_info->commit_root_sem);
10368                 if (caching_ctl) {
10369                         /* Once for the caching bgs list and once for us. */
10370                         put_caching_control(caching_ctl);
10371                         put_caching_control(caching_ctl);
10372                 }
10373         }
10374
10375         spin_lock(&trans->transaction->dirty_bgs_lock);
10376         if (!list_empty(&block_group->dirty_list)) {
10377                 WARN_ON(1);
10378         }
10379         if (!list_empty(&block_group->io_list)) {
10380                 WARN_ON(1);
10381         }
10382         spin_unlock(&trans->transaction->dirty_bgs_lock);
10383         btrfs_remove_free_space_cache(block_group);
10384
10385         spin_lock(&block_group->space_info->lock);
10386         list_del_init(&block_group->ro_list);
10387
10388         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
10389                 WARN_ON(block_group->space_info->total_bytes
10390                         < block_group->key.offset);
10391                 WARN_ON(block_group->space_info->bytes_readonly
10392                         < block_group->key.offset);
10393                 WARN_ON(block_group->space_info->disk_total
10394                         < block_group->key.offset * factor);
10395         }
10396         block_group->space_info->total_bytes -= block_group->key.offset;
10397         block_group->space_info->bytes_readonly -= block_group->key.offset;
10398         block_group->space_info->disk_total -= block_group->key.offset * factor;
10399
10400         spin_unlock(&block_group->space_info->lock);
10401
10402         memcpy(&key, &block_group->key, sizeof(key));
10403
10404         mutex_lock(&fs_info->chunk_mutex);
10405         if (!list_empty(&em->list)) {
10406                 /* We're in the transaction->pending_chunks list. */
10407                 free_extent_map(em);
10408         }
10409         spin_lock(&block_group->lock);
10410         block_group->removed = 1;
10411         /*
10412          * At this point trimming can't start on this block group, because we
10413          * removed the block group from the tree fs_info->block_group_cache_tree
10414          * so no one can't find it anymore and even if someone already got this
10415          * block group before we removed it from the rbtree, they have already
10416          * incremented block_group->trimming - if they didn't, they won't find
10417          * any free space entries because we already removed them all when we
10418          * called btrfs_remove_free_space_cache().
10419          *
10420          * And we must not remove the extent map from the fs_info->mapping_tree
10421          * to prevent the same logical address range and physical device space
10422          * ranges from being reused for a new block group. This is because our
10423          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10424          * completely transactionless, so while it is trimming a range the
10425          * currently running transaction might finish and a new one start,
10426          * allowing for new block groups to be created that can reuse the same
10427          * physical device locations unless we take this special care.
10428          *
10429          * There may also be an implicit trim operation if the file system
10430          * is mounted with -odiscard. The same protections must remain
10431          * in place until the extents have been discarded completely when
10432          * the transaction commit has completed.
10433          */
10434         remove_em = (atomic_read(&block_group->trimming) == 0);
10435         /*
10436          * Make sure a trimmer task always sees the em in the pinned_chunks list
10437          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10438          * before checking block_group->removed).
10439          */
10440         if (!remove_em) {
10441                 /*
10442                  * Our em might be in trans->transaction->pending_chunks which
10443                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10444                  * and so is the fs_info->pinned_chunks list.
10445                  *
10446                  * So at this point we must be holding the chunk_mutex to avoid
10447                  * any races with chunk allocation (more specifically at
10448                  * volumes.c:contains_pending_extent()), to ensure it always
10449                  * sees the em, either in the pending_chunks list or in the
10450                  * pinned_chunks list.
10451                  */
10452                 list_move_tail(&em->list, &fs_info->pinned_chunks);
10453         }
10454         spin_unlock(&block_group->lock);
10455
10456         if (remove_em) {
10457                 struct extent_map_tree *em_tree;
10458
10459                 em_tree = &fs_info->mapping_tree.map_tree;
10460                 write_lock(&em_tree->lock);
10461                 /*
10462                  * The em might be in the pending_chunks list, so make sure the
10463                  * chunk mutex is locked, since remove_extent_mapping() will
10464                  * delete us from that list.
10465                  */
10466                 remove_extent_mapping(em_tree, em);
10467                 write_unlock(&em_tree->lock);
10468                 /* once for the tree */
10469                 free_extent_map(em);
10470         }
10471
10472         mutex_unlock(&fs_info->chunk_mutex);
10473
10474         ret = remove_block_group_free_space(trans, block_group);
10475         if (ret)
10476                 goto out;
10477
10478         btrfs_put_block_group(block_group);
10479         btrfs_put_block_group(block_group);
10480
10481         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10482         if (ret > 0)
10483                 ret = -EIO;
10484         if (ret < 0)
10485                 goto out;
10486
10487         ret = btrfs_del_item(trans, root, path);
10488 out:
10489         btrfs_free_path(path);
10490         return ret;
10491 }
10492
10493 struct btrfs_trans_handle *
10494 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10495                                      const u64 chunk_offset)
10496 {
10497         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10498         struct extent_map *em;
10499         struct map_lookup *map;
10500         unsigned int num_items;
10501
10502         read_lock(&em_tree->lock);
10503         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10504         read_unlock(&em_tree->lock);
10505         ASSERT(em && em->start == chunk_offset);
10506
10507         /*
10508          * We need to reserve 3 + N units from the metadata space info in order
10509          * to remove a block group (done at btrfs_remove_chunk() and at
10510          * btrfs_remove_block_group()), which are used for:
10511          *
10512          * 1 unit for adding the free space inode's orphan (located in the tree
10513          * of tree roots).
10514          * 1 unit for deleting the block group item (located in the extent
10515          * tree).
10516          * 1 unit for deleting the free space item (located in tree of tree
10517          * roots).
10518          * N units for deleting N device extent items corresponding to each
10519          * stripe (located in the device tree).
10520          *
10521          * In order to remove a block group we also need to reserve units in the
10522          * system space info in order to update the chunk tree (update one or
10523          * more device items and remove one chunk item), but this is done at
10524          * btrfs_remove_chunk() through a call to check_system_chunk().
10525          */
10526         map = em->map_lookup;
10527         num_items = 3 + map->num_stripes;
10528         free_extent_map(em);
10529
10530         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10531                                                            num_items, 1);
10532 }
10533
10534 /*
10535  * Process the unused_bgs list and remove any that don't have any allocated
10536  * space inside of them.
10537  */
10538 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10539 {
10540         struct btrfs_block_group_cache *block_group;
10541         struct btrfs_space_info *space_info;
10542         struct btrfs_trans_handle *trans;
10543         int ret = 0;
10544
10545         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10546                 return;
10547
10548         spin_lock(&fs_info->unused_bgs_lock);
10549         while (!list_empty(&fs_info->unused_bgs)) {
10550                 u64 start, end;
10551                 int trimming;
10552
10553                 block_group = list_first_entry(&fs_info->unused_bgs,
10554                                                struct btrfs_block_group_cache,
10555                                                bg_list);
10556                 list_del_init(&block_group->bg_list);
10557
10558                 space_info = block_group->space_info;
10559
10560                 if (ret || btrfs_mixed_space_info(space_info)) {
10561                         btrfs_put_block_group(block_group);
10562                         continue;
10563                 }
10564                 spin_unlock(&fs_info->unused_bgs_lock);
10565
10566                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10567
10568                 /* Don't want to race with allocators so take the groups_sem */
10569                 down_write(&space_info->groups_sem);
10570                 spin_lock(&block_group->lock);
10571                 if (block_group->reserved || block_group->pinned ||
10572                     btrfs_block_group_used(&block_group->item) ||
10573                     block_group->ro ||
10574                     list_is_singular(&block_group->list)) {
10575                         /*
10576                          * We want to bail if we made new allocations or have
10577                          * outstanding allocations in this block group.  We do
10578                          * the ro check in case balance is currently acting on
10579                          * this block group.
10580                          */
10581                         trace_btrfs_skip_unused_block_group(block_group);
10582                         spin_unlock(&block_group->lock);
10583                         up_write(&space_info->groups_sem);
10584                         goto next;
10585                 }
10586                 spin_unlock(&block_group->lock);
10587
10588                 /* We don't want to force the issue, only flip if it's ok. */
10589                 ret = inc_block_group_ro(block_group, 0);
10590                 up_write(&space_info->groups_sem);
10591                 if (ret < 0) {
10592                         ret = 0;
10593                         goto next;
10594                 }
10595
10596                 /*
10597                  * Want to do this before we do anything else so we can recover
10598                  * properly if we fail to join the transaction.
10599                  */
10600                 trans = btrfs_start_trans_remove_block_group(fs_info,
10601                                                      block_group->key.objectid);
10602                 if (IS_ERR(trans)) {
10603                         btrfs_dec_block_group_ro(block_group);
10604                         ret = PTR_ERR(trans);
10605                         goto next;
10606                 }
10607
10608                 /*
10609                  * We could have pending pinned extents for this block group,
10610                  * just delete them, we don't care about them anymore.
10611                  */
10612                 start = block_group->key.objectid;
10613                 end = start + block_group->key.offset - 1;
10614                 /*
10615                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10616                  * btrfs_finish_extent_commit(). If we are at transaction N,
10617                  * another task might be running finish_extent_commit() for the
10618                  * previous transaction N - 1, and have seen a range belonging
10619                  * to the block group in freed_extents[] before we were able to
10620                  * clear the whole block group range from freed_extents[]. This
10621                  * means that task can lookup for the block group after we
10622                  * unpinned it from freed_extents[] and removed it, leading to
10623                  * a BUG_ON() at btrfs_unpin_extent_range().
10624                  */
10625                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10626                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10627                                   EXTENT_DIRTY);
10628                 if (ret) {
10629                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10630                         btrfs_dec_block_group_ro(block_group);
10631                         goto end_trans;
10632                 }
10633                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10634                                   EXTENT_DIRTY);
10635                 if (ret) {
10636                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10637                         btrfs_dec_block_group_ro(block_group);
10638                         goto end_trans;
10639                 }
10640                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10641
10642                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10643                 spin_lock(&space_info->lock);
10644                 spin_lock(&block_group->lock);
10645
10646                 space_info->bytes_pinned -= block_group->pinned;
10647                 space_info->bytes_readonly += block_group->pinned;
10648                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
10649                                    -block_group->pinned,
10650                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
10651                 block_group->pinned = 0;
10652
10653                 spin_unlock(&block_group->lock);
10654                 spin_unlock(&space_info->lock);
10655
10656                 /* DISCARD can flip during remount */
10657                 trimming = btrfs_test_opt(fs_info, DISCARD);
10658
10659                 /* Implicit trim during transaction commit. */
10660                 if (trimming)
10661                         btrfs_get_block_group_trimming(block_group);
10662
10663                 /*
10664                  * Btrfs_remove_chunk will abort the transaction if things go
10665                  * horribly wrong.
10666                  */
10667                 ret = btrfs_remove_chunk(trans, block_group->key.objectid);
10668
10669                 if (ret) {
10670                         if (trimming)
10671                                 btrfs_put_block_group_trimming(block_group);
10672                         goto end_trans;
10673                 }
10674
10675                 /*
10676                  * If we're not mounted with -odiscard, we can just forget
10677                  * about this block group. Otherwise we'll need to wait
10678                  * until transaction commit to do the actual discard.
10679                  */
10680                 if (trimming) {
10681                         spin_lock(&fs_info->unused_bgs_lock);
10682                         /*
10683                          * A concurrent scrub might have added us to the list
10684                          * fs_info->unused_bgs, so use a list_move operation
10685                          * to add the block group to the deleted_bgs list.
10686                          */
10687                         list_move(&block_group->bg_list,
10688                                   &trans->transaction->deleted_bgs);
10689                         spin_unlock(&fs_info->unused_bgs_lock);
10690                         btrfs_get_block_group(block_group);
10691                 }
10692 end_trans:
10693                 btrfs_end_transaction(trans);
10694 next:
10695                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10696                 btrfs_put_block_group(block_group);
10697                 spin_lock(&fs_info->unused_bgs_lock);
10698         }
10699         spin_unlock(&fs_info->unused_bgs_lock);
10700 }
10701
10702 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10703 {
10704         struct btrfs_super_block *disk_super;
10705         u64 features;
10706         u64 flags;
10707         int mixed = 0;
10708         int ret;
10709
10710         disk_super = fs_info->super_copy;
10711         if (!btrfs_super_root(disk_super))
10712                 return -EINVAL;
10713
10714         features = btrfs_super_incompat_flags(disk_super);
10715         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10716                 mixed = 1;
10717
10718         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10719         ret = create_space_info(fs_info, flags);
10720         if (ret)
10721                 goto out;
10722
10723         if (mixed) {
10724                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10725                 ret = create_space_info(fs_info, flags);
10726         } else {
10727                 flags = BTRFS_BLOCK_GROUP_METADATA;
10728                 ret = create_space_info(fs_info, flags);
10729                 if (ret)
10730                         goto out;
10731
10732                 flags = BTRFS_BLOCK_GROUP_DATA;
10733                 ret = create_space_info(fs_info, flags);
10734         }
10735 out:
10736         return ret;
10737 }
10738
10739 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
10740                                    u64 start, u64 end)
10741 {
10742         return unpin_extent_range(fs_info, start, end, false);
10743 }
10744
10745 /*
10746  * It used to be that old block groups would be left around forever.
10747  * Iterating over them would be enough to trim unused space.  Since we
10748  * now automatically remove them, we also need to iterate over unallocated
10749  * space.
10750  *
10751  * We don't want a transaction for this since the discard may take a
10752  * substantial amount of time.  We don't require that a transaction be
10753  * running, but we do need to take a running transaction into account
10754  * to ensure that we're not discarding chunks that were released in
10755  * the current transaction.
10756  *
10757  * Holding the chunks lock will prevent other threads from allocating
10758  * or releasing chunks, but it won't prevent a running transaction
10759  * from committing and releasing the memory that the pending chunks
10760  * list head uses.  For that, we need to take a reference to the
10761  * transaction.
10762  */
10763 static int btrfs_trim_free_extents(struct btrfs_device *device,
10764                                    u64 minlen, u64 *trimmed)
10765 {
10766         u64 start = 0, len = 0;
10767         int ret;
10768
10769         *trimmed = 0;
10770
10771         /* Not writeable = nothing to do. */
10772         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
10773                 return 0;
10774
10775         /* No free space = nothing to do. */
10776         if (device->total_bytes <= device->bytes_used)
10777                 return 0;
10778
10779         ret = 0;
10780
10781         while (1) {
10782                 struct btrfs_fs_info *fs_info = device->fs_info;
10783                 struct btrfs_transaction *trans;
10784                 u64 bytes;
10785
10786                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10787                 if (ret)
10788                         return ret;
10789
10790                 down_read(&fs_info->commit_root_sem);
10791
10792                 spin_lock(&fs_info->trans_lock);
10793                 trans = fs_info->running_transaction;
10794                 if (trans)
10795                         refcount_inc(&trans->use_count);
10796                 spin_unlock(&fs_info->trans_lock);
10797
10798                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10799                                                  &start, &len);
10800                 if (trans)
10801                         btrfs_put_transaction(trans);
10802
10803                 if (ret) {
10804                         up_read(&fs_info->commit_root_sem);
10805                         mutex_unlock(&fs_info->chunk_mutex);
10806                         if (ret == -ENOSPC)
10807                                 ret = 0;
10808                         break;
10809                 }
10810
10811                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10812                 up_read(&fs_info->commit_root_sem);
10813                 mutex_unlock(&fs_info->chunk_mutex);
10814
10815                 if (ret)
10816                         break;
10817
10818                 start += len;
10819                 *trimmed += bytes;
10820
10821                 if (fatal_signal_pending(current)) {
10822                         ret = -ERESTARTSYS;
10823                         break;
10824                 }
10825
10826                 cond_resched();
10827         }
10828
10829         return ret;
10830 }
10831
10832 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
10833 {
10834         struct btrfs_block_group_cache *cache = NULL;
10835         struct btrfs_device *device;
10836         struct list_head *devices;
10837         u64 group_trimmed;
10838         u64 start;
10839         u64 end;
10840         u64 trimmed = 0;
10841         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10842         int ret = 0;
10843
10844         /*
10845          * try to trim all FS space, our block group may start from non-zero.
10846          */
10847         if (range->len == total_bytes)
10848                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10849         else
10850                 cache = btrfs_lookup_block_group(fs_info, range->start);
10851
10852         while (cache) {
10853                 if (cache->key.objectid >= (range->start + range->len)) {
10854                         btrfs_put_block_group(cache);
10855                         break;
10856                 }
10857
10858                 start = max(range->start, cache->key.objectid);
10859                 end = min(range->start + range->len,
10860                                 cache->key.objectid + cache->key.offset);
10861
10862                 if (end - start >= range->minlen) {
10863                         if (!block_group_cache_done(cache)) {
10864                                 ret = cache_block_group(cache, 0);
10865                                 if (ret) {
10866                                         btrfs_put_block_group(cache);
10867                                         break;
10868                                 }
10869                                 ret = wait_block_group_cache_done(cache);
10870                                 if (ret) {
10871                                         btrfs_put_block_group(cache);
10872                                         break;
10873                                 }
10874                         }
10875                         ret = btrfs_trim_block_group(cache,
10876                                                      &group_trimmed,
10877                                                      start,
10878                                                      end,
10879                                                      range->minlen);
10880
10881                         trimmed += group_trimmed;
10882                         if (ret) {
10883                                 btrfs_put_block_group(cache);
10884                                 break;
10885                         }
10886                 }
10887
10888                 cache = next_block_group(fs_info, cache);
10889         }
10890
10891         mutex_lock(&fs_info->fs_devices->device_list_mutex);
10892         devices = &fs_info->fs_devices->alloc_list;
10893         list_for_each_entry(device, devices, dev_alloc_list) {
10894                 ret = btrfs_trim_free_extents(device, range->minlen,
10895                                               &group_trimmed);
10896                 if (ret)
10897                         break;
10898
10899                 trimmed += group_trimmed;
10900         }
10901         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
10902
10903         range->len = trimmed;
10904         return ret;
10905 }
10906
10907 /*
10908  * btrfs_{start,end}_write_no_snapshotting() are similar to
10909  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10910  * data into the page cache through nocow before the subvolume is snapshoted,
10911  * but flush the data into disk after the snapshot creation, or to prevent
10912  * operations while snapshotting is ongoing and that cause the snapshot to be
10913  * inconsistent (writes followed by expanding truncates for example).
10914  */
10915 void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
10916 {
10917         percpu_counter_dec(&root->subv_writers->counter);
10918         cond_wake_up(&root->subv_writers->wait);
10919 }
10920
10921 int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
10922 {
10923         if (atomic_read(&root->will_be_snapshotted))
10924                 return 0;
10925
10926         percpu_counter_inc(&root->subv_writers->counter);
10927         /*
10928          * Make sure counter is updated before we check for snapshot creation.
10929          */
10930         smp_mb();
10931         if (atomic_read(&root->will_be_snapshotted)) {
10932                 btrfs_end_write_no_snapshotting(root);
10933                 return 0;
10934         }
10935         return 1;
10936 }
10937
10938 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
10939 {
10940         while (true) {
10941                 int ret;
10942
10943                 ret = btrfs_start_write_no_snapshotting(root);
10944                 if (ret)
10945                         break;
10946                 wait_var_event(&root->will_be_snapshotted,
10947                                !atomic_read(&root->will_be_snapshotted));
10948         }
10949 }
10950
10951 void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg)
10952 {
10953         struct btrfs_fs_info *fs_info = bg->fs_info;
10954
10955         spin_lock(&fs_info->unused_bgs_lock);
10956         if (list_empty(&bg->bg_list)) {
10957                 btrfs_get_block_group(bg);
10958                 trace_btrfs_add_unused_block_group(bg);
10959                 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
10960         }
10961         spin_unlock(&fs_info->unused_bgs_lock);
10962 }