fs/btrfs/block-group.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include "misc.h"
   4 #include "ctree.h"
   5 #include "block-group.h"
   6 #include "space-info.h"
   7 #include "disk-io.h"
   8 #include "free-space-cache.h"
   9 #include "free-space-tree.h"
  10 #include "volumes.h"
  11 #include "transaction.h"
  12 #include "ref-verify.h"
  13 #include "sysfs.h"
  14 #include "tree-log.h"
  15 #include "delalloc-space.h"
  16 #include "discard.h"
  17 #include "raid56.h"
  18 #include "zoned.h"
  19
  20 /*
  21  * Return target flags in extended format or 0 if restripe for this chunk_type
  22  * is not in progress
  23  *
  24  * Should be called with balance_lock held
  25  */
  26 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
  27 {
  28         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
  29         u64 target = 0;
  30
  31         if (!bctl)
  32                 return 0;
  33
  34         if (flags & BTRFS_BLOCK_GROUP_DATA &&
  35             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
  36                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
  37         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
  38                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
  39                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
  40         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
  41                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
  42                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
  43         }
  44
  45         return target;
  46 }
  47
  48 /*
  49  * @flags: available profiles in extended format (see ctree.h)
  50  *
  51  * Return reduced profile in chunk format.  If profile changing is in progress
  52  * (either running or paused) picks the target profile (if it's already
  53  * available), otherwise falls back to plain reducing.
  54  */
  55 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
  56 {
  57         u64 num_devices = fs_info->fs_devices->rw_devices;
  58         u64 target;
  59         u64 raid_type;
  60         u64 allowed = 0;
  61
  62         /*
  63          * See if restripe for this chunk_type is in progress, if so try to
  64          * reduce to the target profile
  65          */
  66         spin_lock(&fs_info->balance_lock);
  67         target = get_restripe_target(fs_info, flags);
  68         if (target) {
  69                 spin_unlock(&fs_info->balance_lock);
  70                 return extended_to_chunk(target);
  71         }
  72         spin_unlock(&fs_info->balance_lock);
  73
  74         /* First, mask out the RAID levels which aren't possible */
  75         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
  76                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
  77                         allowed |= btrfs_raid_array[raid_type].bg_flag;
  78         }
  79         allowed &= flags;
  80
  81         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
  82                 allowed = BTRFS_BLOCK_GROUP_RAID6;
  83         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
  84                 allowed = BTRFS_BLOCK_GROUP_RAID5;
  85         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
  86                 allowed = BTRFS_BLOCK_GROUP_RAID10;
  87         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
  88                 allowed = BTRFS_BLOCK_GROUP_RAID1;
  89         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
  90                 allowed = BTRFS_BLOCK_GROUP_RAID0;
  91
  92         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
  93
  94         return extended_to_chunk(flags | allowed);
  95 }
  96
  97 u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
  98 {
  99         unsigned seq;
 100         u64 flags;
 101
 102         do {
 103                 flags = orig_flags;
 104                 seq = read_seqbegin(&fs_info->profiles_lock);
 105
 106                 if (flags & BTRFS_BLOCK_GROUP_DATA)
 107                         flags |= fs_info->avail_data_alloc_bits;
 108                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 109                         flags |= fs_info->avail_system_alloc_bits;
 110                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
 111                         flags |= fs_info->avail_metadata_alloc_bits;
 112         } while (read_seqretry(&fs_info->profiles_lock, seq));
 113
 114         return btrfs_reduce_alloc_profile(fs_info, flags);
 115 }
 116
 117 void btrfs_get_block_group(struct btrfs_block_group *cache)
 118 {
 119         refcount_inc(&cache->refs);
 120 }
 121
 122 void btrfs_put_block_group(struct btrfs_block_group *cache)
 123 {
 124         if (refcount_dec_and_test(&cache->refs)) {
 125                 WARN_ON(cache->pinned > 0);
 126                 WARN_ON(cache->reserved > 0);
 127
 128                 /*
 129                  * A block_group shouldn't be on the discard_list anymore.
 130                  * Remove the block_group from the discard_list to prevent us
 131                  * from causing a panic due to NULL pointer dereference.
 132                  */
 133                 if (WARN_ON(!list_empty(&cache->discard_list)))
 134                         btrfs_discard_cancel_work(&cache->fs_info->discard_ctl,
 135                                                   cache);
 136
 137                 /*
 138                  * If not empty, someone is still holding mutex of
 139                  * full_stripe_lock, which can only be released by caller.
 140                  * And it will definitely cause use-after-free when caller
 141                  * tries to release full stripe lock.
 142                  *
 143                  * No better way to resolve, but only to warn.
 144                  */
 145                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 146                 kfree(cache->free_space_ctl);
 147                 kfree(cache);
 148         }
 149 }
 150
 151 /*
 152  * This adds the block group to the fs_info rb tree for the block group cache
 153  */
 154 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 155                                        struct btrfs_block_group *block_group)
 156 {
 157         struct rb_node **p;
 158         struct rb_node *parent = NULL;
 159         struct btrfs_block_group *cache;
 160
 161         ASSERT(block_group->length != 0);
 162
 163         spin_lock(&info->block_group_cache_lock);
 164         p = &info->block_group_cache_tree.rb_node;
 165
 166         while (*p) {
 167                 parent = *p;
 168                 cache = rb_entry(parent, struct btrfs_block_group, cache_node);
 169                 if (block_group->start < cache->start) {
 170                         p = &(*p)->rb_left;
 171                 } else if (block_group->start > cache->start) {
 172                         p = &(*p)->rb_right;
 173                 } else {
 174                         spin_unlock(&info->block_group_cache_lock);
 175                         return -EEXIST;
 176                 }
 177         }
 178
 179         rb_link_node(&block_group->cache_node, parent, p);
 180         rb_insert_color(&block_group->cache_node,
 181                         &info->block_group_cache_tree);
 182
 183         if (info->first_logical_byte > block_group->start)
 184                 info->first_logical_byte = block_group->start;
 185
 186         spin_unlock(&info->block_group_cache_lock);
 187
 188         return 0;
 189 }
 190
 191 /*
 192  * This will return the block group at or after bytenr if contains is 0, else
 193  * it will return the block group that contains the bytenr
 194  */
 195 static struct btrfs_block_group *block_group_cache_tree_search(
 196                 struct btrfs_fs_info *info, u64 bytenr, int contains)
 197 {
 198         struct btrfs_block_group *cache, *ret = NULL;
 199         struct rb_node *n;
 200         u64 end, start;
 201
 202         spin_lock(&info->block_group_cache_lock);
 203         n = info->block_group_cache_tree.rb_node;
 204
 205         while (n) {
 206                 cache = rb_entry(n, struct btrfs_block_group, cache_node);
 207                 end = cache->start + cache->length - 1;
 208                 start = cache->start;
 209
 210                 if (bytenr < start) {
 211                         if (!contains && (!ret || start < ret->start))
 212                                 ret = cache;
 213                         n = n->rb_left;
 214                 } else if (bytenr > start) {
 215                         if (contains && bytenr <= end) {
 216                                 ret = cache;
 217                                 break;
 218                         }
 219                         n = n->rb_right;
 220                 } else {
 221                         ret = cache;
 222                         break;
 223                 }
 224         }
 225         if (ret) {
 226                 btrfs_get_block_group(ret);
 227                 if (bytenr == 0 && info->first_logical_byte > ret->start)
 228                         info->first_logical_byte = ret->start;
 229         }
 230         spin_unlock(&info->block_group_cache_lock);
 231
 232         return ret;
 233 }
 234
 235 /*
 236  * Return the block group that starts at or after bytenr
 237  */
 238 struct btrfs_block_group *btrfs_lookup_first_block_group(
 239                 struct btrfs_fs_info *info, u64 bytenr)
 240 {
 241         return block_group_cache_tree_search(info, bytenr, 0);
 242 }
 243
 244 /*
 245  * Return the block group that contains the given bytenr
 246  */
 247 struct btrfs_block_group *btrfs_lookup_block_group(
 248                 struct btrfs_fs_info *info, u64 bytenr)
 249 {
 250         return block_group_cache_tree_search(info, bytenr, 1);
 251 }
 252
 253 struct btrfs_block_group *btrfs_next_block_group(
 254                 struct btrfs_block_group *cache)
 255 {
 256         struct btrfs_fs_info *fs_info = cache->fs_info;
 257         struct rb_node *node;
 258
 259         spin_lock(&fs_info->block_group_cache_lock);
 260
 261         /* If our block group was removed, we need a full search. */
 262         if (RB_EMPTY_NODE(&cache->cache_node)) {
 263                 const u64 next_bytenr = cache->start + cache->length;
 264
 265                 spin_unlock(&fs_info->block_group_cache_lock);
 266                 btrfs_put_block_group(cache);
 267                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
 268         }
 269         node = rb_next(&cache->cache_node);
 270         btrfs_put_block_group(cache);
 271         if (node) {
 272                 cache = rb_entry(node, struct btrfs_block_group, cache_node);
 273                 btrfs_get_block_group(cache);
 274         } else
 275                 cache = NULL;
 276         spin_unlock(&fs_info->block_group_cache_lock);
 277         return cache;
 278 }
 279
 280 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
 281 {
 282         struct btrfs_block_group *bg;
 283         bool ret = true;
 284
 285         bg = btrfs_lookup_block_group(fs_info, bytenr);
 286         if (!bg)
 287                 return false;
 288
 289         spin_lock(&bg->lock);
 290         if (bg->ro)
 291                 ret = false;
 292         else
 293                 atomic_inc(&bg->nocow_writers);
 294         spin_unlock(&bg->lock);
 295
 296         /* No put on block group, done by btrfs_dec_nocow_writers */
 297         if (!ret)
 298                 btrfs_put_block_group(bg);
 299
 300         return ret;
 301 }
 302
 303 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
 304 {
 305         struct btrfs_block_group *bg;
 306
 307         bg = btrfs_lookup_block_group(fs_info, bytenr);
 308         ASSERT(bg);
 309         if (atomic_dec_and_test(&bg->nocow_writers))
 310                 wake_up_var(&bg->nocow_writers);
 311         /*
 312          * Once for our lookup and once for the lookup done by a previous call
 313          * to btrfs_inc_nocow_writers()
 314          */
 315         btrfs_put_block_group(bg);
 316         btrfs_put_block_group(bg);
 317 }
 318
 319 void btrfs_wait_nocow_writers(struct btrfs_block_group *bg)
 320 {
 321         wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
 322 }
 323
 324 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
 325                                         const u64 start)
 326 {
 327         struct btrfs_block_group *bg;
 328
 329         bg = btrfs_lookup_block_group(fs_info, start);
 330         ASSERT(bg);
 331         if (atomic_dec_and_test(&bg->reservations))
 332                 wake_up_var(&bg->reservations);
 333         btrfs_put_block_group(bg);
 334 }
 335
 336 void btrfs_wait_block_group_reservations(struct btrfs_block_group *bg)
 337 {
 338         struct btrfs_space_info *space_info = bg->space_info;
 339
 340         ASSERT(bg->ro);
 341
 342         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
 343                 return;
 344
 345         /*
 346          * Our block group is read only but before we set it to read only,
 347          * some task might have had allocated an extent from it already, but it
 348          * has not yet created a respective ordered extent (and added it to a
 349          * root's list of ordered extents).
 350          * Therefore wait for any task currently allocating extents, since the
 351          * block group's reservations counter is incremented while a read lock
 352          * on the groups' semaphore is held and decremented after releasing
 353          * the read access on that semaphore and creating the ordered extent.
 354          */
 355         down_write(&space_info->groups_sem);
 356         up_write(&space_info->groups_sem);
 357
 358         wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
 359 }
 360
 361 struct btrfs_caching_control *btrfs_get_caching_control(
 362                 struct btrfs_block_group *cache)
 363 {
 364         struct btrfs_caching_control *ctl;
 365
 366         spin_lock(&cache->lock);
 367         if (!cache->caching_ctl) {
 368                 spin_unlock(&cache->lock);
 369                 return NULL;
 370         }
 371
 372         ctl = cache->caching_ctl;
 373         refcount_inc(&ctl->count);
 374         spin_unlock(&cache->lock);
 375         return ctl;
 376 }
 377
 378 void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
 379 {
 380         if (refcount_dec_and_test(&ctl->count))
 381                 kfree(ctl);
 382 }
 383
 384 /*
 385  * When we wait for progress in the block group caching, its because our
 386  * allocation attempt failed at least once.  So, we must sleep and let some
 387  * progress happen before we try again.
 388  *
 389  * This function will sleep at least once waiting for new free space to show
 390  * up, and then it will check the block group free space numbers for our min
 391  * num_bytes.  Another option is to have it go ahead and look in the rbtree for
 392  * a free extent of a given size, but this is a good start.
 393  *
 394  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
 395  * any of the information in this block group.
 396  */
 397 void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache,
 398                                            u64 num_bytes)
 399 {
 400         struct btrfs_caching_control *caching_ctl;
 401
 402         caching_ctl = btrfs_get_caching_control(cache);
 403         if (!caching_ctl)
 404                 return;
 405
 406         wait_event(caching_ctl->wait, btrfs_block_group_done(cache) ||
 407                    (cache->free_space_ctl->free_space >= num_bytes));
 408
 409         btrfs_put_caching_control(caching_ctl);
 410 }
 411
 412 int btrfs_wait_block_group_cache_done(struct btrfs_block_group *cache)
 413 {
 414         struct btrfs_caching_control *caching_ctl;
 415         int ret = 0;
 416
 417         caching_ctl = btrfs_get_caching_control(cache);
 418         if (!caching_ctl)
 419                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
 420
 421         wait_event(caching_ctl->wait, btrfs_block_group_done(cache));
 422         if (cache->cached == BTRFS_CACHE_ERROR)
 423                 ret = -EIO;
 424         btrfs_put_caching_control(caching_ctl);
 425         return ret;
 426 }
 427
 428 static bool space_cache_v1_done(struct btrfs_block_group *cache)
 429 {
 430         bool ret;
 431
 432         spin_lock(&cache->lock);
 433         ret = cache->cached != BTRFS_CACHE_FAST;
 434         spin_unlock(&cache->lock);
 435
 436         return ret;
 437 }
 438
 439 void btrfs_wait_space_cache_v1_finished(struct btrfs_block_group *cache,
 440                                 struct btrfs_caching_control *caching_ctl)
 441 {
 442         wait_event(caching_ctl->wait, space_cache_v1_done(cache));
 443 }
 444
 445 #ifdef CONFIG_BTRFS_DEBUG
 446 static void fragment_free_space(struct btrfs_block_group *block_group)
 447 {
 448         struct btrfs_fs_info *fs_info = block_group->fs_info;
 449         u64 start = block_group->start;
 450         u64 len = block_group->length;
 451         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 452                 fs_info->nodesize : fs_info->sectorsize;
 453         u64 step = chunk << 1;
 454
 455         while (len > chunk) {
 456                 btrfs_remove_free_space(block_group, start, chunk);
 457                 start += step;
 458                 if (len < step)
 459                         len = 0;
 460                 else
 461                         len -= step;
 462         }
 463 }
 464 #endif
 465
 466 /*
 467  * This is only called by btrfs_cache_block_group, since we could have freed
 468  * extents we need to check the pinned_extents for any extents that can't be
 469  * used yet since their free space will be released as soon as the transaction
 470  * commits.
 471  */
 472 u64 add_new_free_space(struct btrfs_block_group *block_group, u64 start, u64 end)
 473 {
 474         struct btrfs_fs_info *info = block_group->fs_info;
 475         u64 extent_start, extent_end, size, total_added = 0;
 476         int ret;
 477
 478         while (start < end) {
 479                 ret = find_first_extent_bit(&info->excluded_extents, start,
 480                                             &extent_start, &extent_end,
 481                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 482                                             NULL);
 483                 if (ret)
 484                         break;
 485
 486                 if (extent_start <= start) {
 487                         start = extent_end + 1;
 488                 } else if (extent_start > start && extent_start < end) {
 489                         size = extent_start - start;
 490                         total_added += size;
 491                         ret = btrfs_add_free_space_async_trimmed(block_group,
 492                                                                  start, size);
 493                         BUG_ON(ret); /* -ENOMEM or logic error */
 494                         start = extent_end + 1;
 495                 } else {
 496                         break;
 497                 }
 498         }
 499
 500         if (start < end) {
 501                 size = end - start;
 502                 total_added += size;
 503                 ret = btrfs_add_free_space_async_trimmed(block_group, start,
 504                                                          size);
 505                 BUG_ON(ret); /* -ENOMEM or logic error */
 506         }
 507
 508         return total_added;
 509 }
 510
 511 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 512 {
 513         struct btrfs_block_group *block_group = caching_ctl->block_group;
 514         struct btrfs_fs_info *fs_info = block_group->fs_info;
 515         struct btrfs_root *extent_root = fs_info->extent_root;
 516         struct btrfs_path *path;
 517         struct extent_buffer *leaf;
 518         struct btrfs_key key;
 519         u64 total_found = 0;
 520         u64 last = 0;
 521         u32 nritems;
 522         int ret;
 523         bool wakeup = true;
 524
 525         path = btrfs_alloc_path();
 526         if (!path)
 527                 return -ENOMEM;
 528
 529         last = max_t(u64, block_group->start, BTRFS_SUPER_INFO_OFFSET);
 530
 531 #ifdef CONFIG_BTRFS_DEBUG
 532         /*
 533          * If we're fragmenting we don't want to make anybody think we can
 534          * allocate from this block group until we've had a chance to fragment
 535          * the free space.
 536          */
 537         if (btrfs_should_fragment_free_space(block_group))
 538                 wakeup = false;
 539 #endif
 540         /*
 541          * We don't want to deadlock with somebody trying to allocate a new
 542          * extent for the extent root while also trying to search the extent
 543          * root to add free space.  So we skip locking and search the commit
 544          * root, since its read-only
 545          */
 546         path->skip_locking = 1;
 547         path->search_commit_root = 1;
 548         path->reada = READA_FORWARD;
 549
 550         key.objectid = last;
 551         key.offset = 0;
 552         key.type = BTRFS_EXTENT_ITEM_KEY;
 553
 554 next:
 555         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 556         if (ret < 0)
 557                 goto out;
 558
 559         leaf = path->nodes[0];
 560         nritems = btrfs_header_nritems(leaf);
 561
 562         while (1) {
 563                 if (btrfs_fs_closing(fs_info) > 1) {
 564                         last = (u64)-1;
 565                         break;
 566                 }
 567
 568                 if (path->slots[0] < nritems) {
 569                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 570                 } else {
 571                         ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
 572                         if (ret)
 573                                 break;
 574
 575                         if (need_resched() ||
 576                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 577                                 if (wakeup)
 578                                         caching_ctl->progress = last;
 579                                 btrfs_release_path(path);
 580                                 up_read(&fs_info->commit_root_sem);
 581                                 mutex_unlock(&caching_ctl->mutex);
 582                                 cond_resched();
 583                                 mutex_lock(&caching_ctl->mutex);
 584                                 down_read(&fs_info->commit_root_sem);
 585                                 goto next;
 586                         }
 587
 588                         ret = btrfs_next_leaf(extent_root, path);
 589                         if (ret < 0)
 590                                 goto out;
 591                         if (ret)
 592                                 break;
 593                         leaf = path->nodes[0];
 594                         nritems = btrfs_header_nritems(leaf);
 595                         continue;
 596                 }
 597
 598                 if (key.objectid < last) {
 599                         key.objectid = last;
 600                         key.offset = 0;
 601                         key.type = BTRFS_EXTENT_ITEM_KEY;
 602
 603                         if (wakeup)
 604                                 caching_ctl->progress = last;
 605                         btrfs_release_path(path);
 606                         goto next;
 607                 }
 608
 609                 if (key.objectid < block_group->start) {
 610                         path->slots[0]++;
 611                         continue;
 612                 }
 613
 614                 if (key.objectid >= block_group->start + block_group->length)
 615                         break;
 616
 617                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 618                     key.type == BTRFS_METADATA_ITEM_KEY) {
 619                         total_found += add_new_free_space(block_group, last,
 620                                                           key.objectid);
 621                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 622                                 last = key.objectid +
 623                                         fs_info->nodesize;
 624                         else
 625                                 last = key.objectid + key.offset;
 626
 627                         if (total_found > CACHING_CTL_WAKE_UP) {
 628                                 total_found = 0;
 629                                 if (wakeup)
 630                                         wake_up(&caching_ctl->wait);
 631                         }
 632                 }
 633                 path->slots[0]++;
 634         }
 635         ret = 0;
 636
 637         total_found += add_new_free_space(block_group, last,
 638                                 block_group->start + block_group->length);
 639         caching_ctl->progress = (u64)-1;
 640
 641 out:
 642         btrfs_free_path(path);
 643         return ret;
 644 }
 645
 646 static noinline void caching_thread(struct btrfs_work *work)
 647 {
 648         struct btrfs_block_group *block_group;
 649         struct btrfs_fs_info *fs_info;
 650         struct btrfs_caching_control *caching_ctl;
 651         int ret;
 652
 653         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 654         block_group = caching_ctl->block_group;
 655         fs_info = block_group->fs_info;
 656
 657         mutex_lock(&caching_ctl->mutex);
 658         down_read(&fs_info->commit_root_sem);
 659
 660         if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
 661                 ret = load_free_space_cache(block_group);
 662                 if (ret == 1) {
 663                         ret = 0;
 664                         goto done;
 665                 }
 666
 667                 /*
 668                  * We failed to load the space cache, set ourselves to
 669                  * CACHE_STARTED and carry on.
 670                  */
 671                 spin_lock(&block_group->lock);
 672                 block_group->cached = BTRFS_CACHE_STARTED;
 673                 spin_unlock(&block_group->lock);
 674                 wake_up(&caching_ctl->wait);
 675         }
 676
 677         /*
 678          * If we are in the transaction that populated the free space tree we
 679          * can't actually cache from the free space tree as our commit root and
 680          * real root are the same, so we could change the contents of the blocks
 681          * while caching.  Instead do the slow caching in this case, and after
 682          * the transaction has committed we will be safe.
 683          */
 684         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
 685             !(test_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags)))
 686                 ret = load_free_space_tree(caching_ctl);
 687         else
 688                 ret = load_extent_tree_free(caching_ctl);
 689 done:
 690         spin_lock(&block_group->lock);
 691         block_group->caching_ctl = NULL;
 692         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 693         spin_unlock(&block_group->lock);
 694
 695 #ifdef CONFIG_BTRFS_DEBUG
 696         if (btrfs_should_fragment_free_space(block_group)) {
 697                 u64 bytes_used;
 698
 699                 spin_lock(&block_group->space_info->lock);
 700                 spin_lock(&block_group->lock);
 701                 bytes_used = block_group->length - block_group->used;
 702                 block_group->space_info->bytes_used += bytes_used >> 1;
 703                 spin_unlock(&block_group->lock);
 704                 spin_unlock(&block_group->space_info->lock);
 705                 fragment_free_space(block_group);
 706         }
 707 #endif
 708
 709         caching_ctl->progress = (u64)-1;
 710
 711         up_read(&fs_info->commit_root_sem);
 712         btrfs_free_excluded_extents(block_group);
 713         mutex_unlock(&caching_ctl->mutex);
 714
 715         wake_up(&caching_ctl->wait);
 716
 717         btrfs_put_caching_control(caching_ctl);
 718         btrfs_put_block_group(block_group);
 719 }
 720
 721 int btrfs_cache_block_group(struct btrfs_block_group *cache, int load_cache_only)
 722 {
 723         DEFINE_WAIT(wait);
 724         struct btrfs_fs_info *fs_info = cache->fs_info;
 725         struct btrfs_caching_control *caching_ctl = NULL;
 726         int ret = 0;
 727
 728         /* Allocator for zoned filesystems does not use the cache at all */
 729         if (btrfs_is_zoned(fs_info))
 730                 return 0;
 731
 732         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 733         if (!caching_ctl)
 734                 return -ENOMEM;
 735
 736         INIT_LIST_HEAD(&caching_ctl->list);
 737         mutex_init(&caching_ctl->mutex);
 738         init_waitqueue_head(&caching_ctl->wait);
 739         caching_ctl->block_group = cache;
 740         caching_ctl->progress = cache->start;
 741         refcount_set(&caching_ctl->count, 2);
 742         btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL);
 743
 744         spin_lock(&cache->lock);
 745         if (cache->cached != BTRFS_CACHE_NO) {
 746                 kfree(caching_ctl);
 747
 748                 caching_ctl = cache->caching_ctl;
 749                 if (caching_ctl)
 750                         refcount_inc(&caching_ctl->count);
 751                 spin_unlock(&cache->lock);
 752                 goto out;
 753         }
 754         WARN_ON(cache->caching_ctl);
 755         cache->caching_ctl = caching_ctl;
 756         if (btrfs_test_opt(fs_info, SPACE_CACHE))
 757                 cache->cached = BTRFS_CACHE_FAST;
 758         else
 759                 cache->cached = BTRFS_CACHE_STARTED;
 760         cache->has_caching_ctl = 1;
 761         spin_unlock(&cache->lock);
 762
 763         spin_lock(&fs_info->block_group_cache_lock);
 764         refcount_inc(&caching_ctl->count);
 765         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 766         spin_unlock(&fs_info->block_group_cache_lock);
 767
 768         btrfs_get_block_group(cache);
 769
 770         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 771 out:
 772         if (load_cache_only && caching_ctl)
 773                 btrfs_wait_space_cache_v1_finished(cache, caching_ctl);
 774         if (caching_ctl)
 775                 btrfs_put_caching_control(caching_ctl);
 776
 777         return ret;
 778 }
 779
 780 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
 781 {
 782         u64 extra_flags = chunk_to_extended(flags) &
 783                                 BTRFS_EXTENDED_PROFILE_MASK;
 784
 785         write_seqlock(&fs_info->profiles_lock);
 786         if (flags & BTRFS_BLOCK_GROUP_DATA)
 787                 fs_info->avail_data_alloc_bits &= ~extra_flags;
 788         if (flags & BTRFS_BLOCK_GROUP_METADATA)
 789                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
 790         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 791                 fs_info->avail_system_alloc_bits &= ~extra_flags;
 792         write_sequnlock(&fs_info->profiles_lock);
 793 }
 794
 795 /*
 796  * Clear incompat bits for the following feature(s):
 797  *
 798  * - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
 799  *            in the whole filesystem
 800  *
 801  * - RAID1C34 - same as above for RAID1C3 and RAID1C4 block groups
 802  */
 803 static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
 804 {
 805         bool found_raid56 = false;
 806         bool found_raid1c34 = false;
 807
 808         if ((flags & BTRFS_BLOCK_GROUP_RAID56_MASK) ||
 809             (flags & BTRFS_BLOCK_GROUP_RAID1C3) ||
 810             (flags & BTRFS_BLOCK_GROUP_RAID1C4)) {
 811                 struct list_head *head = &fs_info->space_info;
 812                 struct btrfs_space_info *sinfo;
 813
 814                 list_for_each_entry_rcu(sinfo, head, list) {
 815                         down_read(&sinfo->groups_sem);
 816                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
 817                                 found_raid56 = true;
 818                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
 819                                 found_raid56 = true;
 820                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C3]))
 821                                 found_raid1c34 = true;
 822                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C4]))
 823                                 found_raid1c34 = true;
 824                         up_read(&sinfo->groups_sem);
 825                 }
 826                 if (!found_raid56)
 827                         btrfs_clear_fs_incompat(fs_info, RAID56);
 828                 if (!found_raid1c34)
 829                         btrfs_clear_fs_incompat(fs_info, RAID1C34);
 830         }
 831 }
 832
 833 static int remove_block_group_item(struct btrfs_trans_handle *trans,
 834                                    struct btrfs_path *path,
 835                                    struct btrfs_block_group *block_group)
 836 {
 837         struct btrfs_fs_info *fs_info = trans->fs_info;
 838         struct btrfs_root *root;
 839         struct btrfs_key key;
 840         int ret;
 841
 842         root = fs_info->extent_root;
 843         key.objectid = block_group->start;
 844         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
 845         key.offset = block_group->length;
 846
 847         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 848         if (ret > 0)
 849                 ret = -ENOENT;
 850         if (ret < 0)
 851                 return ret;
 852
 853         ret = btrfs_del_item(trans, root, path);
 854         return ret;
 855 }
 856
 857 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 858                              u64 group_start, struct extent_map *em)
 859 {
 860         struct btrfs_fs_info *fs_info = trans->fs_info;
 861         struct btrfs_path *path;
 862         struct btrfs_block_group *block_group;
 863         struct btrfs_free_cluster *cluster;
 864         struct inode *inode;
 865         struct kobject *kobj = NULL;
 866         int ret;
 867         int index;
 868         int factor;
 869         struct btrfs_caching_control *caching_ctl = NULL;
 870         bool remove_em;
 871         bool remove_rsv = false;
 872
 873         block_group = btrfs_lookup_block_group(fs_info, group_start);
 874         BUG_ON(!block_group);
 875         BUG_ON(!block_group->ro);
 876
 877         trace_btrfs_remove_block_group(block_group);
 878         /*
 879          * Free the reserved super bytes from this block group before
 880          * remove it.
 881          */
 882         btrfs_free_excluded_extents(block_group);
 883         btrfs_free_ref_tree_range(fs_info, block_group->start,
 884                                   block_group->length);
 885
 886         index = btrfs_bg_flags_to_raid_index(block_group->flags);
 887         factor = btrfs_bg_type_to_factor(block_group->flags);
 888
 889         /* make sure this block group isn't part of an allocation cluster */
 890         cluster = &fs_info->data_alloc_cluster;
 891         spin_lock(&cluster->refill_lock);
 892         btrfs_return_cluster_to_free_space(block_group, cluster);
 893         spin_unlock(&cluster->refill_lock);
 894
 895         /*
 896          * make sure this block group isn't part of a metadata
 897          * allocation cluster
 898          */
 899         cluster = &fs_info->meta_alloc_cluster;
 900         spin_lock(&cluster->refill_lock);
 901         btrfs_return_cluster_to_free_space(block_group, cluster);
 902         spin_unlock(&cluster->refill_lock);
 903
 904         btrfs_clear_treelog_bg(block_group);
 905
 906         path = btrfs_alloc_path();
 907         if (!path) {
 908                 ret = -ENOMEM;
 909                 goto out;
 910         }
 911
 912         /*
 913          * get the inode first so any iput calls done for the io_list
 914          * aren't the final iput (no unlinks allowed now)
 915          */
 916         inode = lookup_free_space_inode(block_group, path);
 917
 918         mutex_lock(&trans->transaction->cache_write_mutex);
 919         /*
 920          * Make sure our free space cache IO is done before removing the
 921          * free space inode
 922          */
 923         spin_lock(&trans->transaction->dirty_bgs_lock);
 924         if (!list_empty(&block_group->io_list)) {
 925                 list_del_init(&block_group->io_list);
 926
 927                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
 928
 929                 spin_unlock(&trans->transaction->dirty_bgs_lock);
 930                 btrfs_wait_cache_io(trans, block_group, path);
 931                 btrfs_put_block_group(block_group);
 932                 spin_lock(&trans->transaction->dirty_bgs_lock);
 933         }
 934
 935         if (!list_empty(&block_group->dirty_list)) {
 936                 list_del_init(&block_group->dirty_list);
 937                 remove_rsv = true;
 938                 btrfs_put_block_group(block_group);
 939         }
 940         spin_unlock(&trans->transaction->dirty_bgs_lock);
 941         mutex_unlock(&trans->transaction->cache_write_mutex);
 942
 943         ret = btrfs_remove_free_space_inode(trans, inode, block_group);
 944         if (ret)
 945                 goto out;
 946
 947         spin_lock(&fs_info->block_group_cache_lock);
 948         rb_erase(&block_group->cache_node,
 949                  &fs_info->block_group_cache_tree);
 950         RB_CLEAR_NODE(&block_group->cache_node);
 951
 952         /* Once for the block groups rbtree */
 953         btrfs_put_block_group(block_group);
 954
 955         if (fs_info->first_logical_byte == block_group->start)
 956                 fs_info->first_logical_byte = (u64)-1;
 957         spin_unlock(&fs_info->block_group_cache_lock);
 958
 959         down_write(&block_group->space_info->groups_sem);
 960         /*
 961          * we must use list_del_init so people can check to see if they
 962          * are still on the list after taking the semaphore
 963          */
 964         list_del_init(&block_group->list);
 965         if (list_empty(&block_group->space_info->block_groups[index])) {
 966                 kobj = block_group->space_info->block_group_kobjs[index];
 967                 block_group->space_info->block_group_kobjs[index] = NULL;
 968                 clear_avail_alloc_bits(fs_info, block_group->flags);
 969         }
 970         up_write(&block_group->space_info->groups_sem);
 971         clear_incompat_bg_bits(fs_info, block_group->flags);
 972         if (kobj) {
 973                 kobject_del(kobj);
 974                 kobject_put(kobj);
 975         }
 976
 977         if (block_group->has_caching_ctl)
 978                 caching_ctl = btrfs_get_caching_control(block_group);
 979         if (block_group->cached == BTRFS_CACHE_STARTED)
 980                 btrfs_wait_block_group_cache_done(block_group);
 981         if (block_group->has_caching_ctl) {
 982                 spin_lock(&fs_info->block_group_cache_lock);
 983                 if (!caching_ctl) {
 984                         struct btrfs_caching_control *ctl;
 985
 986                         list_for_each_entry(ctl,
 987                                     &fs_info->caching_block_groups, list)
 988                                 if (ctl->block_group == block_group) {
 989                                         caching_ctl = ctl;
 990                                         refcount_inc(&caching_ctl->count);
 991                                         break;
 992                                 }
 993                 }
 994                 if (caching_ctl)
 995                         list_del_init(&caching_ctl->list);
 996                 spin_unlock(&fs_info->block_group_cache_lock);
 997                 if (caching_ctl) {
 998                         /* Once for the caching bgs list and once for us. */
 999                         btrfs_put_caching_control(caching_ctl);
1000                         btrfs_put_caching_control(caching_ctl);
1001                 }
1002         }
1003
1004         spin_lock(&trans->transaction->dirty_bgs_lock);
1005         WARN_ON(!list_empty(&block_group->dirty_list));
1006         WARN_ON(!list_empty(&block_group->io_list));
1007         spin_unlock(&trans->transaction->dirty_bgs_lock);
1008
1009         btrfs_remove_free_space_cache(block_group);
1010
1011         spin_lock(&block_group->space_info->lock);
1012         list_del_init(&block_group->ro_list);
1013
1014         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1015                 WARN_ON(block_group->space_info->total_bytes
1016                         < block_group->length);
1017                 WARN_ON(block_group->space_info->bytes_readonly
1018                         < block_group->length - block_group->zone_unusable);
1019                 WARN_ON(block_group->space_info->bytes_zone_unusable
1020                         < block_group->zone_unusable);
1021                 WARN_ON(block_group->space_info->disk_total
1022                         < block_group->length * factor);
1023         }
1024         block_group->space_info->total_bytes -= block_group->length;
1025         block_group->space_info->bytes_readonly -=
1026                 (block_group->length - block_group->zone_unusable);
1027         block_group->space_info->bytes_zone_unusable -=
1028                 block_group->zone_unusable;
1029         block_group->space_info->disk_total -= block_group->length * factor;
1030
1031         spin_unlock(&block_group->space_info->lock);
1032
1033         /*
1034          * Remove the free space for the block group from the free space tree
1035          * and the block group's item from the extent tree before marking the
1036          * block group as removed. This is to prevent races with tasks that
1037          * freeze and unfreeze a block group, this task and another task
1038          * allocating a new block group - the unfreeze task ends up removing
1039          * the block group's extent map before the task calling this function
1040          * deletes the block group item from the extent tree, allowing for
1041          * another task to attempt to create another block group with the same
1042          * item key (and failing with -EEXIST and a transaction abort).
1043          */
1044         ret = remove_block_group_free_space(trans, block_group);
1045         if (ret)
1046                 goto out;
1047
1048         ret = remove_block_group_item(trans, path, block_group);
1049         if (ret < 0)
1050                 goto out;
1051
1052         spin_lock(&block_group->lock);
1053         block_group->removed = 1;
1054         /*
1055          * At this point trimming or scrub can't start on this block group,
1056          * because we removed the block group from the rbtree
1057          * fs_info->block_group_cache_tree so no one can't find it anymore and
1058          * even if someone already got this block group before we removed it
1059          * from the rbtree, they have already incremented block_group->frozen -
1060          * if they didn't, for the trimming case they won't find any free space
1061          * entries because we already removed them all when we called
1062          * btrfs_remove_free_space_cache().
1063          *
1064          * And we must not remove the extent map from the fs_info->mapping_tree
1065          * to prevent the same logical address range and physical device space
1066          * ranges from being reused for a new block group. This is needed to
1067          * avoid races with trimming and scrub.
1068          *
1069          * An fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
1070          * completely transactionless, so while it is trimming a range the
1071          * currently running transaction might finish and a new one start,
1072          * allowing for new block groups to be created that can reuse the same
1073          * physical device locations unless we take this special care.
1074          *
1075          * There may also be an implicit trim operation if the file system
1076          * is mounted with -odiscard. The same protections must remain
1077          * in place until the extents have been discarded completely when
1078          * the transaction commit has completed.
1079          */
1080         remove_em = (atomic_read(&block_group->frozen) == 0);
1081         spin_unlock(&block_group->lock);
1082
1083         if (remove_em) {
1084                 struct extent_map_tree *em_tree;
1085
1086                 em_tree = &fs_info->mapping_tree;
1087                 write_lock(&em_tree->lock);
1088                 remove_extent_mapping(em_tree, em);
1089                 write_unlock(&em_tree->lock);
1090                 /* once for the tree */
1091                 free_extent_map(em);
1092         }
1093
1094 out:
1095         /* Once for the lookup reference */
1096         btrfs_put_block_group(block_group);
1097         if (remove_rsv)
1098                 btrfs_delayed_refs_rsv_release(fs_info, 1);
1099         btrfs_free_path(path);
1100         return ret;
1101 }
1102
1103 struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
1104                 struct btrfs_fs_info *fs_info, const u64 chunk_offset)
1105 {
1106         struct extent_map_tree *em_tree = &fs_info->mapping_tree;
1107         struct extent_map *em;
1108         struct map_lookup *map;
1109         unsigned int num_items;
1110
1111         read_lock(&em_tree->lock);
1112         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1113         read_unlock(&em_tree->lock);
1114         ASSERT(em && em->start == chunk_offset);
1115
1116         /*
1117          * We need to reserve 3 + N units from the metadata space info in order
1118          * to remove a block group (done at btrfs_remove_chunk() and at
1119          * btrfs_remove_block_group()), which are used for:
1120          *
1121          * 1 unit for adding the free space inode's orphan (located in the tree
1122          * of tree roots).
1123          * 1 unit for deleting the block group item (located in the extent
1124          * tree).
1125          * 1 unit for deleting the free space item (located in tree of tree
1126          * roots).
1127          * N units for deleting N device extent items corresponding to each
1128          * stripe (located in the device tree).
1129          *
1130          * In order to remove a block group we also need to reserve units in the
1131          * system space info in order to update the chunk tree (update one or
1132          * more device items and remove one chunk item), but this is done at
1133          * btrfs_remove_chunk() through a call to check_system_chunk().
1134          */
1135         map = em->map_lookup;
1136         num_items = 3 + map->num_stripes;
1137         free_extent_map(em);
1138
1139         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
1140                                                            num_items);
1141 }
1142
1143 /*
1144  * Mark block group @cache read-only, so later write won't happen to block
1145  * group @cache.
1146  *
1147  * If @force is not set, this function will only mark the block group readonly
1148  * if we have enough free space (1M) in other metadata/system block groups.
1149  * If @force is not set, this function will mark the block group readonly
1150  * without checking free space.
1151  *
1152  * NOTE: This function doesn't care if other block groups can contain all the
1153  * data in this block group. That check should be done by relocation routine,
1154  * not this function.
1155  */
1156 static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
1157 {
1158         struct btrfs_space_info *sinfo = cache->space_info;
1159         u64 num_bytes;
1160         int ret = -ENOSPC;
1161
1162         spin_lock(&sinfo->lock);
1163         spin_lock(&cache->lock);
1164
1165         if (cache->ro) {
1166                 cache->ro++;
1167                 ret = 0;
1168                 goto out;
1169         }
1170
1171         num_bytes = cache->length - cache->reserved - cache->pinned -
1172                     cache->bytes_super - cache->zone_unusable - cache->used;
1173
1174         /*
1175          * Data never overcommits, even in mixed mode, so do just the straight
1176          * check of left over space in how much we have allocated.
1177          */
1178         if (force) {
1179                 ret = 0;
1180         } else if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) {
1181                 u64 sinfo_used = btrfs_space_info_used(sinfo, true);
1182
1183                 /*
1184                  * Here we make sure if we mark this bg RO, we still have enough
1185                  * free space as buffer.
1186                  */
1187                 if (sinfo_used + num_bytes <= sinfo->total_bytes)
1188                         ret = 0;
1189         } else {
1190                 /*
1191                  * We overcommit metadata, so we need to do the
1192                  * btrfs_can_overcommit check here, and we need to pass in
1193                  * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of
1194                  * leeway to allow us to mark this block group as read only.
1195                  */
1196                 if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes,
1197                                          BTRFS_RESERVE_NO_FLUSH))
1198                         ret = 0;
1199         }
1200
1201         if (!ret) {
1202                 sinfo->bytes_readonly += num_bytes;
1203                 if (btrfs_is_zoned(cache->fs_info)) {
1204                         /* Migrate zone_unusable bytes to readonly */
1205                         sinfo->bytes_readonly += cache->zone_unusable;
1206                         sinfo->bytes_zone_unusable -= cache->zone_unusable;
1207                         cache->zone_unusable = 0;
1208                 }
1209                 cache->ro++;
1210                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
1211         }
1212 out:
1213         spin_unlock(&cache->lock);
1214         spin_unlock(&sinfo->lock);
1215         if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
1216                 btrfs_info(cache->fs_info,
1217                         "unable to make block group %llu ro", cache->start);
1218                 btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
1219         }
1220         return ret;
1221 }
1222
1223 static bool clean_pinned_extents(struct btrfs_trans_handle *trans,
1224                                  struct btrfs_block_group *bg)
1225 {
1226         struct btrfs_fs_info *fs_info = bg->fs_info;
1227         struct btrfs_transaction *prev_trans = NULL;
1228         const u64 start = bg->start;
1229         const u64 end = start + bg->length - 1;
1230         int ret;
1231
1232         spin_lock(&fs_info->trans_lock);
1233         if (trans->transaction->list.prev != &fs_info->trans_list) {
1234                 prev_trans = list_last_entry(&trans->transaction->list,
1235                                              struct btrfs_transaction, list);
1236                 refcount_inc(&prev_trans->use_count);
1237         }
1238         spin_unlock(&fs_info->trans_lock);
1239
1240         /*
1241          * Hold the unused_bg_unpin_mutex lock to avoid racing with
1242          * btrfs_finish_extent_commit(). If we are at transaction N, another
1243          * task might be running finish_extent_commit() for the previous
1244          * transaction N - 1, and have seen a range belonging to the block
1245          * group in pinned_extents before we were able to clear the whole block
1246          * group range from pinned_extents. This means that task can lookup for
1247          * the block group after we unpinned it from pinned_extents and removed
1248          * it, leading to a BUG_ON() at unpin_extent_range().
1249          */
1250         mutex_lock(&fs_info->unused_bg_unpin_mutex);
1251         if (prev_trans) {
1252                 ret = clear_extent_bits(&prev_trans->pinned_extents, start, end,
1253                                         EXTENT_DIRTY);
1254                 if (ret)
1255                         goto out;
1256         }
1257
1258         ret = clear_extent_bits(&trans->transaction->pinned_extents, start, end,
1259                                 EXTENT_DIRTY);
1260 out:
1261         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
1262         if (prev_trans)
1263                 btrfs_put_transaction(prev_trans);
1264
1265         return ret == 0;
1266 }
1267
1268 /*
1269  * Process the unused_bgs list and remove any that don't have any allocated
1270  * space inside of them.
1271  */
1272 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
1273 {
1274         struct btrfs_block_group *block_group;
1275         struct btrfs_space_info *space_info;
1276         struct btrfs_trans_handle *trans;
1277         const bool async_trim_enabled = btrfs_test_opt(fs_info, DISCARD_ASYNC);
1278         int ret = 0;
1279
1280         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1281                 return;
1282
1283         /*
1284          * Long running balances can keep us blocked here for eternity, so
1285          * simply skip deletion if we're unable to get the mutex.
1286          */
1287         if (!mutex_trylock(&fs_info->delete_unused_bgs_mutex))
1288                 return;
1289
1290         spin_lock(&fs_info->unused_bgs_lock);
1291         while (!list_empty(&fs_info->unused_bgs)) {
1292                 int trimming;
1293
1294                 block_group = list_first_entry(&fs_info->unused_bgs,
1295                                                struct btrfs_block_group,
1296                                                bg_list);
1297                 list_del_init(&block_group->bg_list);
1298
1299                 space_info = block_group->space_info;
1300
1301                 if (ret || btrfs_mixed_space_info(space_info)) {
1302                         btrfs_put_block_group(block_group);
1303                         continue;
1304                 }
1305                 spin_unlock(&fs_info->unused_bgs_lock);
1306
1307                 btrfs_discard_cancel_work(&fs_info->discard_ctl, block_group);
1308
1309                 /* Don't want to race with allocators so take the groups_sem */
1310                 down_write(&space_info->groups_sem);
1311
1312                 /*
1313                  * Async discard moves the final block group discard to be prior
1314                  * to the unused_bgs code path.  Therefore, if it's not fully
1315                  * trimmed, punt it back to the async discard lists.
1316                  */
1317                 if (btrfs_test_opt(fs_info, DISCARD_ASYNC) &&
1318                     !btrfs_is_free_space_trimmed(block_group)) {
1319                         trace_btrfs_skip_unused_block_group(block_group);
1320                         up_write(&space_info->groups_sem);
1321                         /* Requeue if we failed because of async discard */
1322                         btrfs_discard_queue_work(&fs_info->discard_ctl,
1323                                                  block_group);
1324                         goto next;
1325                 }
1326
1327                 spin_lock(&block_group->lock);
1328                 if (block_group->reserved || block_group->pinned ||
1329                     block_group->used || block_group->ro ||
1330                     list_is_singular(&block_group->list)) {
1331                         /*
1332                          * We want to bail if we made new allocations or have
1333                          * outstanding allocations in this block group.  We do
1334                          * the ro check in case balance is currently acting on
1335                          * this block group.
1336                          */
1337                         trace_btrfs_skip_unused_block_group(block_group);
1338                         spin_unlock(&block_group->lock);
1339                         up_write(&space_info->groups_sem);
1340                         goto next;
1341                 }
1342                 spin_unlock(&block_group->lock);
1343
1344                 /* We don't want to force the issue, only flip if it's ok. */
1345                 ret = inc_block_group_ro(block_group, 0);
1346                 up_write(&space_info->groups_sem);
1347                 if (ret < 0) {
1348                         ret = 0;
1349                         goto next;
1350                 }
1351
1352                 /*
1353                  * Want to do this before we do anything else so we can recover
1354                  * properly if we fail to join the transaction.
1355                  */
1356                 trans = btrfs_start_trans_remove_block_group(fs_info,
1357                                                      block_group->start);
1358                 if (IS_ERR(trans)) {
1359                         btrfs_dec_block_group_ro(block_group);
1360                         ret = PTR_ERR(trans);
1361                         goto next;
1362                 }
1363
1364                 /*
1365                  * We could have pending pinned extents for this block group,
1366                  * just delete them, we don't care about them anymore.
1367                  */
1368                 if (!clean_pinned_extents(trans, block_group)) {
1369                         btrfs_dec_block_group_ro(block_group);
1370                         goto end_trans;
1371                 }
1372
1373                 /*
1374                  * At this point, the block_group is read only and should fail
1375                  * new allocations.  However, btrfs_finish_extent_commit() can
1376                  * cause this block_group to be placed back on the discard
1377                  * lists because now the block_group isn't fully discarded.
1378                  * Bail here and try again later after discarding everything.
1379                  */
1380                 spin_lock(&fs_info->discard_ctl.lock);
1381                 if (!list_empty(&block_group->discard_list)) {
1382                         spin_unlock(&fs_info->discard_ctl.lock);
1383                         btrfs_dec_block_group_ro(block_group);
1384                         btrfs_discard_queue_work(&fs_info->discard_ctl,
1385                                                  block_group);
1386                         goto end_trans;
1387                 }
1388                 spin_unlock(&fs_info->discard_ctl.lock);
1389
1390                 /* Reset pinned so btrfs_put_block_group doesn't complain */
1391                 spin_lock(&space_info->lock);
1392                 spin_lock(&block_group->lock);
1393
1394                 btrfs_space_info_update_bytes_pinned(fs_info, space_info,
1395                                                      -block_group->pinned);
1396                 space_info->bytes_readonly += block_group->pinned;
1397                 __btrfs_mod_total_bytes_pinned(space_info, -block_group->pinned);
1398                 block_group->pinned = 0;
1399
1400                 spin_unlock(&block_group->lock);
1401                 spin_unlock(&space_info->lock);
1402
1403                 /*
1404                  * The normal path here is an unused block group is passed here,
1405                  * then trimming is handled in the transaction commit path.
1406                  * Async discard interposes before this to do the trimming
1407                  * before coming down the unused block group path as trimming
1408                  * will no longer be done later in the transaction commit path.
1409                  */
1410                 if (!async_trim_enabled && btrfs_test_opt(fs_info, DISCARD_ASYNC))
1411                         goto flip_async;
1412
1413                 /*
1414                  * DISCARD can flip during remount. On zoned filesystems, we
1415                  * need to reset sequential-required zones.
1416                  */
1417                 trimming = btrfs_test_opt(fs_info, DISCARD_SYNC) ||
1418                                 btrfs_is_zoned(fs_info);
1419
1420                 /* Implicit trim during transaction commit. */
1421                 if (trimming)
1422                         btrfs_freeze_block_group(block_group);
1423
1424                 /*
1425                  * Btrfs_remove_chunk will abort the transaction if things go
1426                  * horribly wrong.
1427                  */
1428                 ret = btrfs_remove_chunk(trans, block_group->start);
1429
1430                 if (ret) {
1431                         if (trimming)
1432                                 btrfs_unfreeze_block_group(block_group);
1433                         goto end_trans;
1434                 }
1435
1436                 /*
1437                  * If we're not mounted with -odiscard, we can just forget
1438                  * about this block group. Otherwise we'll need to wait
1439                  * until transaction commit to do the actual discard.
1440                  */
1441                 if (trimming) {
1442                         spin_lock(&fs_info->unused_bgs_lock);
1443                         /*
1444                          * A concurrent scrub might have added us to the list
1445                          * fs_info->unused_bgs, so use a list_move operation
1446                          * to add the block group to the deleted_bgs list.
1447                          */
1448                         list_move(&block_group->bg_list,
1449                                   &trans->transaction->deleted_bgs);
1450                         spin_unlock(&fs_info->unused_bgs_lock);
1451                         btrfs_get_block_group(block_group);
1452                 }
1453 end_trans:
1454                 btrfs_end_transaction(trans);
1455 next:
1456                 btrfs_put_block_group(block_group);
1457                 spin_lock(&fs_info->unused_bgs_lock);
1458         }
1459         spin_unlock(&fs_info->unused_bgs_lock);
1460         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
1461         return;
1462
1463 flip_async:
1464         btrfs_end_transaction(trans);
1465         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
1466         btrfs_put_block_group(block_group);
1467         btrfs_discard_punt_unused_bgs_list(fs_info);
1468 }
1469
1470 void btrfs_mark_bg_unused(struct btrfs_block_group *bg)
1471 {
1472         struct btrfs_fs_info *fs_info = bg->fs_info;
1473
1474         spin_lock(&fs_info->unused_bgs_lock);
1475         if (list_empty(&bg->bg_list)) {
1476                 btrfs_get_block_group(bg);
1477                 trace_btrfs_add_unused_block_group(bg);
1478                 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
1479         }
1480         spin_unlock(&fs_info->unused_bgs_lock);
1481 }
1482
1483 static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
1484                            struct btrfs_path *path)
1485 {
1486         struct extent_map_tree *em_tree;
1487         struct extent_map *em;
1488         struct btrfs_block_group_item bg;
1489         struct extent_buffer *leaf;
1490         int slot;
1491         u64 flags;
1492         int ret = 0;
1493
1494         slot = path->slots[0];
1495         leaf = path->nodes[0];
1496
1497         em_tree = &fs_info->mapping_tree;
1498         read_lock(&em_tree->lock);
1499         em = lookup_extent_mapping(em_tree, key->objectid, key->offset);
1500         read_unlock(&em_tree->lock);
1501         if (!em) {
1502                 btrfs_err(fs_info,
1503                           "logical %llu len %llu found bg but no related chunk",
1504                           key->objectid, key->offset);
1505                 return -ENOENT;
1506         }
1507
1508         if (em->start != key->objectid || em->len != key->offset) {
1509                 btrfs_err(fs_info,
1510                         "block group %llu len %llu mismatch with chunk %llu len %llu",
1511                         key->objectid, key->offset, em->start, em->len);
1512                 ret = -EUCLEAN;
1513                 goto out_free_em;
1514         }
1515
1516         read_extent_buffer(leaf, &bg, btrfs_item_ptr_offset(leaf, slot),
1517                            sizeof(bg));
1518         flags = btrfs_stack_block_group_flags(&bg) &
1519                 BTRFS_BLOCK_GROUP_TYPE_MASK;
1520
1521         if (flags != (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1522                 btrfs_err(fs_info,
1523 "block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
1524                           key->objectid, key->offset, flags,
1525                           (BTRFS_BLOCK_GROUP_TYPE_MASK & em->map_lookup->type));
1526                 ret = -EUCLEAN;
1527         }
1528
1529 out_free_em:
1530         free_extent_map(em);
1531         return ret;
1532 }
1533
1534 static int find_first_block_group(struct btrfs_fs_info *fs_info,
1535                                   struct btrfs_path *path,
1536                                   struct btrfs_key *key)
1537 {
1538         struct btrfs_root *root = fs_info->extent_root;
1539         int ret;
1540         struct btrfs_key found_key;
1541         struct extent_buffer *leaf;
1542         int slot;
1543
1544         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
1545         if (ret < 0)
1546                 return ret;
1547
1548         while (1) {
1549                 slot = path->slots[0];
1550                 leaf = path->nodes[0];
1551                 if (slot >= btrfs_header_nritems(leaf)) {
1552                         ret = btrfs_next_leaf(root, path);
1553                         if (ret == 0)
1554                                 continue;
1555                         if (ret < 0)
1556                                 goto out;
1557                         break;
1558                 }
1559                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1560
1561                 if (found_key.objectid >= key->objectid &&
1562                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1563                         ret = read_bg_from_eb(fs_info, &found_key, path);
1564                         break;
1565                 }
1566
1567                 path->slots[0]++;
1568         }
1569 out:
1570         return ret;
1571 }
1572
1573 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1574 {
1575         u64 extra_flags = chunk_to_extended(flags) &
1576                                 BTRFS_EXTENDED_PROFILE_MASK;
1577
1578         write_seqlock(&fs_info->profiles_lock);
1579         if (flags & BTRFS_BLOCK_GROUP_DATA)
1580                 fs_info->avail_data_alloc_bits |= extra_flags;
1581         if (flags & BTRFS_BLOCK_GROUP_METADATA)
1582                 fs_info->avail_metadata_alloc_bits |= extra_flags;
1583         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1584                 fs_info->avail_system_alloc_bits |= extra_flags;
1585         write_sequnlock(&fs_info->profiles_lock);
1586 }
1587
1588 /**
1589  * Map a physical disk address to a list of logical addresses
1590  *
1591  * @fs_info:       the filesystem
1592  * @chunk_start:   logical address of block group
1593  * @bdev:          physical device to resolve, can be NULL to indicate any device
1594  * @physical:      physical address to map to logical addresses
1595  * @logical:       return array of logical addresses which map to @physical
1596  * @naddrs:        length of @logical
1597  * @stripe_len:    size of IO stripe for the given block group
1598  *
1599  * Maps a particular @physical disk address to a list of @logical addresses.
1600  * Used primarily to exclude those portions of a block group that contain super
1601  * block copies.
1602  */
1603 int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
1604                      struct block_device *bdev, u64 physical, u64 **logical,
1605                      int *naddrs, int *stripe_len)
1606 {
1607         struct extent_map *em;
1608         struct map_lookup *map;
1609         u64 *buf;
1610         u64 bytenr;
1611         u64 data_stripe_length;
1612         u64 io_stripe_size;
1613         int i, nr = 0;
1614         int ret = 0;
1615
1616         em = btrfs_get_chunk_map(fs_info, chunk_start, 1);
1617         if (IS_ERR(em))
1618                 return -EIO;
1619
1620         map = em->map_lookup;
1621         data_stripe_length = em->orig_block_len;
1622         io_stripe_size = map->stripe_len;
1623         chunk_start = em->start;
1624
1625         /* For RAID5/6 adjust to a full IO stripe length */
1626         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
1627                 io_stripe_size = map->stripe_len * nr_data_stripes(map);
1628
1629         buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
1630         if (!buf) {
1631                 ret = -ENOMEM;
1632                 goto out;
1633         }
1634
1635         for (i = 0; i < map->num_stripes; i++) {
1636                 bool already_inserted = false;
1637                 u64 stripe_nr;
1638                 u64 offset;
1639                 int j;
1640
1641                 if (!in_range(physical, map->stripes[i].physical,
1642                               data_stripe_length))
1643                         continue;
1644
1645                 if (bdev && map->stripes[i].dev->bdev != bdev)
1646                         continue;
1647
1648                 stripe_nr = physical - map->stripes[i].physical;
1649                 stripe_nr = div64_u64_rem(stripe_nr, map->stripe_len, &offset);
1650
1651                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1652                         stripe_nr = stripe_nr * map->num_stripes + i;
1653                         stripe_nr = div_u64(stripe_nr, map->sub_stripes);
1654                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1655                         stripe_nr = stripe_nr * map->num_stripes + i;
1656                 }
1657                 /*
1658                  * The remaining case would be for RAID56, multiply by
1659                  * nr_data_stripes().  Alternatively, just use rmap_len below
1660                  * instead of map->stripe_len
1661                  */
1662
1663                 bytenr = chunk_start + stripe_nr * io_stripe_size + offset;
1664
1665                 /* Ensure we don't add duplicate addresses */
1666                 for (j = 0; j < nr; j++) {
1667                         if (buf[j] == bytenr) {
1668                                 already_inserted = true;
1669                                 break;
1670                         }
1671                 }
1672
1673                 if (!already_inserted)
1674                         buf[nr++] = bytenr;
1675         }
1676
1677         *logical = buf;
1678         *naddrs = nr;
1679         *stripe_len = io_stripe_size;
1680 out:
1681         free_extent_map(em);
1682         return ret;
1683 }
1684
1685 static int exclude_super_stripes(struct btrfs_block_group *cache)
1686 {
1687         struct btrfs_fs_info *fs_info = cache->fs_info;
1688         const bool zoned = btrfs_is_zoned(fs_info);
1689         u64 bytenr;
1690         u64 *logical;
1691         int stripe_len;
1692         int i, nr, ret;
1693
1694         if (cache->start < BTRFS_SUPER_INFO_OFFSET) {
1695                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->start;
1696                 cache->bytes_super += stripe_len;
1697                 ret = btrfs_add_excluded_extent(fs_info, cache->start,
1698                                                 stripe_len);
1699                 if (ret)
1700                         return ret;
1701         }
1702
1703         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1704                 bytenr = btrfs_sb_offset(i);
1705                 ret = btrfs_rmap_block(fs_info, cache->start, NULL,
1706                                        bytenr, &logical, &nr, &stripe_len);
1707                 if (ret)
1708                         return ret;
1709
1710                 /* Shouldn't have super stripes in sequential zones */
1711                 if (zoned && nr) {
1712                         btrfs_err(fs_info,
1713                         "zoned: block group %llu must not contain super block",
1714                                   cache->start);
1715                         return -EUCLEAN;
1716                 }
1717
1718                 while (nr--) {
1719                         u64 len = min_t(u64, stripe_len,
1720                                 cache->start + cache->length - logical[nr]);
1721
1722                         cache->bytes_super += len;
1723                         ret = btrfs_add_excluded_extent(fs_info, logical[nr],
1724                                                         len);
1725                         if (ret) {
1726                                 kfree(logical);
1727                                 return ret;
1728                         }
1729                 }
1730
1731                 kfree(logical);
1732         }
1733         return 0;
1734 }
1735
1736 static void link_block_group(struct btrfs_block_group *cache)
1737 {
1738         struct btrfs_space_info *space_info = cache->space_info;
1739         int index = btrfs_bg_flags_to_raid_index(cache->flags);
1740
1741         down_write(&space_info->groups_sem);
1742         list_add_tail(&cache->list, &space_info->block_groups[index]);
1743         up_write(&space_info->groups_sem);
1744 }
1745
1746 static struct btrfs_block_group *btrfs_create_block_group_cache(
1747                 struct btrfs_fs_info *fs_info, u64 start)
1748 {
1749         struct btrfs_block_group *cache;
1750
1751         cache = kzalloc(sizeof(*cache), GFP_NOFS);
1752         if (!cache)
1753                 return NULL;
1754
1755         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
1756                                         GFP_NOFS);
1757         if (!cache->free_space_ctl) {
1758                 kfree(cache);
1759                 return NULL;
1760         }
1761
1762         cache->start = start;
1763
1764         cache->fs_info = fs_info;
1765         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
1766
1767         cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
1768
1769         refcount_set(&cache->refs, 1);
1770         spin_lock_init(&cache->lock);
1771         init_rwsem(&cache->data_rwsem);
1772         INIT_LIST_HEAD(&cache->list);
1773         INIT_LIST_HEAD(&cache->cluster_list);
1774         INIT_LIST_HEAD(&cache->bg_list);
1775         INIT_LIST_HEAD(&cache->ro_list);
1776         INIT_LIST_HEAD(&cache->discard_list);
1777         INIT_LIST_HEAD(&cache->dirty_list);
1778         INIT_LIST_HEAD(&cache->io_list);
1779         btrfs_init_free_space_ctl(cache, cache->free_space_ctl);
1780         atomic_set(&cache->frozen, 0);
1781         mutex_init(&cache->free_space_lock);
1782         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
1783
1784         return cache;
1785 }
1786
1787 /*
1788  * Iterate all chunks and verify that each of them has the corresponding block
1789  * group
1790  */
1791 static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
1792 {
1793         struct extent_map_tree *map_tree = &fs_info->mapping_tree;
1794         struct extent_map *em;
1795         struct btrfs_block_group *bg;
1796         u64 start = 0;
1797         int ret = 0;
1798
1799         while (1) {
1800                 read_lock(&map_tree->lock);
1801                 /*
1802                  * lookup_extent_mapping will return the first extent map
1803                  * intersecting the range, so setting @len to 1 is enough to
1804                  * get the first chunk.
1805                  */
1806                 em = lookup_extent_mapping(map_tree, start, 1);
1807                 read_unlock(&map_tree->lock);
1808                 if (!em)
1809                         break;
1810
1811                 bg = btrfs_lookup_block_group(fs_info, em->start);
1812                 if (!bg) {
1813                         btrfs_err(fs_info,
1814         "chunk start=%llu len=%llu doesn't have corresponding block group",
1815                                      em->start, em->len);
1816                         ret = -EUCLEAN;
1817                         free_extent_map(em);
1818                         break;
1819                 }
1820                 if (bg->start != em->start || bg->length != em->len ||
1821                     (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
1822                     (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1823                         btrfs_err(fs_info,
1824 "chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
1825                                 em->start, em->len,
1826                                 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
1827                                 bg->start, bg->length,
1828                                 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
1829                         ret = -EUCLEAN;
1830                         free_extent_map(em);
1831                         btrfs_put_block_group(bg);
1832                         break;
1833                 }
1834                 start = em->start + em->len;
1835                 free_extent_map(em);
1836                 btrfs_put_block_group(bg);
1837         }
1838         return ret;
1839 }
1840
1841 static int read_one_block_group(struct btrfs_fs_info *info,
1842                                 struct btrfs_block_group_item *bgi,
1843                                 const struct btrfs_key *key,
1844                                 int need_clear)
1845 {
1846         struct btrfs_block_group *cache;
1847         struct btrfs_space_info *space_info;
1848         const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS);
1849         int ret;
1850
1851         ASSERT(key->type == BTRFS_BLOCK_GROUP_ITEM_KEY);
1852
1853         cache = btrfs_create_block_group_cache(info, key->objectid);
1854         if (!cache)
1855                 return -ENOMEM;
1856
1857         cache->length = key->offset;
1858         cache->used = btrfs_stack_block_group_used(bgi);
1859         cache->flags = btrfs_stack_block_group_flags(bgi);
1860
1861         set_free_space_tree_thresholds(cache);
1862
1863         if (need_clear) {
1864                 /*
1865                  * When we mount with old space cache, we need to
1866                  * set BTRFS_DC_CLEAR and set dirty flag.
1867                  *
1868                  * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
1869                  *    truncate the old free space cache inode and
1870                  *    setup a new one.
1871                  * b) Setting 'dirty flag' makes sure that we flush
1872                  *    the new space cache info onto disk.
1873                  */
1874                 if (btrfs_test_opt(info, SPACE_CACHE))
1875                         cache->disk_cache_state = BTRFS_DC_CLEAR;
1876         }
1877         if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
1878             (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
1879                         btrfs_err(info,
1880 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
1881                                   cache->start);
1882                         ret = -EINVAL;
1883                         goto error;
1884         }
1885
1886         ret = btrfs_load_block_group_zone_info(cache, false);
1887         if (ret) {
1888                 btrfs_err(info, "zoned: failed to load zone info of bg %llu",
1889                           cache->start);
1890                 goto error;
1891         }
1892
1893         /*
1894          * We need to exclude the super stripes now so that the space info has
1895          * super bytes accounted for, otherwise we'll think we have more space
1896          * than we actually do.
1897          */
1898         ret = exclude_super_stripes(cache);
1899         if (ret) {
1900                 /* We may have excluded something, so call this just in case. */
1901                 btrfs_free_excluded_extents(cache);
1902                 goto error;
1903         }
1904
1905         /*
1906          * For zoned filesystem, space after the allocation offset is the only
1907          * free space for a block group. So, we don't need any caching work.
1908          * btrfs_calc_zone_unusable() will set the amount of free space and
1909          * zone_unusable space.
1910          *
1911          * For regular filesystem, check for two cases, either we are full, and
1912          * therefore don't need to bother with the caching work since we won't
1913          * find any space, or we are empty, and we can just add all the space
1914          * in and be done with it.  This saves us _a_lot_ of time, particularly
1915          * in the full case.
1916          */
1917         if (btrfs_is_zoned(info)) {
1918                 btrfs_calc_zone_unusable(cache);
1919         } else if (cache->length == cache->used) {
1920                 cache->last_byte_to_unpin = (u64)-1;
1921                 cache->cached = BTRFS_CACHE_FINISHED;
1922                 btrfs_free_excluded_extents(cache);
1923         } else if (cache->used == 0) {
1924                 cache->last_byte_to_unpin = (u64)-1;
1925                 cache->cached = BTRFS_CACHE_FINISHED;
1926                 add_new_free_space(cache, cache->start,
1927                                    cache->start + cache->length);
1928                 btrfs_free_excluded_extents(cache);
1929         }
1930
1931         ret = btrfs_add_block_group_cache(info, cache);
1932         if (ret) {
1933                 btrfs_remove_free_space_cache(cache);
1934                 goto error;
1935         }
1936         trace_btrfs_add_block_group(info, cache, 0);
1937         btrfs_update_space_info(info, cache->flags, cache->length,
1938                                 cache->used, cache->bytes_super,
1939                                 cache->zone_unusable, &space_info);
1940
1941         cache->space_info = space_info;
1942
1943         link_block_group(cache);
1944
1945         set_avail_alloc_bits(info, cache->flags);
1946         if (btrfs_chunk_readonly(info, cache->start)) {
1947                 inc_block_group_ro(cache, 1);
1948         } else if (cache->used == 0) {
1949                 ASSERT(list_empty(&cache->bg_list));
1950                 if (btrfs_test_opt(info, DISCARD_ASYNC))
1951                         btrfs_discard_queue_work(&info->discard_ctl, cache);
1952                 else
1953                         btrfs_mark_bg_unused(cache);
1954         }
1955         return 0;
1956 error:
1957         btrfs_put_block_group(cache);
1958         return ret;
1959 }
1960
1961 static int fill_dummy_bgs(struct btrfs_fs_info *fs_info)
1962 {
1963         struct extent_map_tree *em_tree = &fs_info->mapping_tree;
1964         struct btrfs_space_info *space_info;
1965         struct rb_node *node;
1966         int ret = 0;
1967
1968         for (node = rb_first_cached(&em_tree->map); node; node = rb_next(node)) {
1969                 struct extent_map *em;
1970                 struct map_lookup *map;
1971                 struct btrfs_block_group *bg;
1972
1973                 em = rb_entry(node, struct extent_map, rb_node);
1974                 map = em->map_lookup;
1975                 bg = btrfs_create_block_group_cache(fs_info, em->start);
1976                 if (!bg) {
1977                         ret = -ENOMEM;
1978                         break;
1979                 }
1980
1981                 /* Fill dummy cache as FULL */
1982                 bg->length = em->len;
1983                 bg->flags = map->type;
1984                 bg->last_byte_to_unpin = (u64)-1;
1985                 bg->cached = BTRFS_CACHE_FINISHED;
1986                 bg->used = em->len;
1987                 bg->flags = map->type;
1988                 ret = btrfs_add_block_group_cache(fs_info, bg);
1989                 if (ret) {
1990                         btrfs_remove_free_space_cache(bg);
1991                         btrfs_put_block_group(bg);
1992                         break;
1993                 }
1994                 btrfs_update_space_info(fs_info, bg->flags, em->len, em->len,
1995                                         0, 0, &space_info);
1996                 bg->space_info = space_info;
1997                 link_block_group(bg);
1998
1999                 set_avail_alloc_bits(fs_info, bg->flags);
2000         }
2001         if (!ret)
2002                 btrfs_init_global_block_rsv(fs_info);
2003         return ret;
2004 }
2005
2006 int btrfs_read_block_groups(struct btrfs_fs_info *info)
2007 {
2008         struct btrfs_path *path;
2009         int ret;
2010         struct btrfs_block_group *cache;
2011         struct btrfs_space_info *space_info;
2012         struct btrfs_key key;
2013         int need_clear = 0;
2014         u64 cache_gen;
2015
2016         if (!info->extent_root)
2017                 return fill_dummy_bgs(info);
2018
2019         key.objectid = 0;
2020         key.offset = 0;
2021         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2022         path = btrfs_alloc_path();
2023         if (!path)
2024                 return -ENOMEM;
2025
2026         cache_gen = btrfs_super_cache_generation(info->super_copy);
2027         if (btrfs_test_opt(info, SPACE_CACHE) &&
2028             btrfs_super_generation(info->super_copy) != cache_gen)
2029                 need_clear = 1;
2030         if (btrfs_test_opt(info, CLEAR_CACHE))
2031                 need_clear = 1;
2032
2033         while (1) {
2034                 struct btrfs_block_group_item bgi;
2035                 struct extent_buffer *leaf;
2036                 int slot;
2037
2038                 ret = find_first_block_group(info, path, &key);
2039                 if (ret > 0)
2040                         break;
2041                 if (ret != 0)
2042                         goto error;
2043
2044                 leaf = path->nodes[0];
2045                 slot = path->slots[0];
2046
2047                 read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
2048                                    sizeof(bgi));
2049
2050                 btrfs_item_key_to_cpu(leaf, &key, slot);
2051                 btrfs_release_path(path);
2052                 ret = read_one_block_group(info, &bgi, &key, need_clear);
2053                 if (ret < 0)
2054                         goto error;
2055                 key.objectid += key.offset;
2056                 key.offset = 0;
2057         }
2058         btrfs_release_path(path);
2059
2060         list_for_each_entry(space_info, &info->space_info, list) {
2061                 int i;
2062
2063                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2064                         if (list_empty(&space_info->block_groups[i]))
2065                                 continue;
2066                         cache = list_first_entry(&space_info->block_groups[i],
2067                                                  struct btrfs_block_group,
2068                                                  list);
2069                         btrfs_sysfs_add_block_group_type(cache);
2070                 }
2071
2072                 if (!(btrfs_get_alloc_profile(info, space_info->flags) &
2073                       (BTRFS_BLOCK_GROUP_RAID10 |
2074                        BTRFS_BLOCK_GROUP_RAID1_MASK |
2075                        BTRFS_BLOCK_GROUP_RAID56_MASK |
2076                        BTRFS_BLOCK_GROUP_DUP)))
2077                         continue;
2078                 /*
2079                  * Avoid allocating from un-mirrored block group if there are
2080                  * mirrored block groups.
2081                  */
2082                 list_for_each_entry(cache,
2083                                 &space_info->block_groups[BTRFS_RAID_RAID0],
2084                                 list)
2085                         inc_block_group_ro(cache, 1);
2086                 list_for_each_entry(cache,
2087                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
2088                                 list)
2089                         inc_block_group_ro(cache, 1);
2090         }
2091
2092         btrfs_init_global_block_rsv(info);
2093         ret = check_chunk_block_group_mappings(info);
2094 error:
2095         btrfs_free_path(path);
2096         return ret;
2097 }
2098
2099 static int insert_block_group_item(struct btrfs_trans_handle *trans,
2100                                    struct btrfs_block_group *block_group)
2101 {
2102         struct btrfs_fs_info *fs_info = trans->fs_info;
2103         struct btrfs_block_group_item bgi;
2104         struct btrfs_root *root;
2105         struct btrfs_key key;
2106
2107         spin_lock(&block_group->lock);
2108         btrfs_set_stack_block_group_used(&bgi, block_group->used);
2109         btrfs_set_stack_block_group_chunk_objectid(&bgi,
2110                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2111         btrfs_set_stack_block_group_flags(&bgi, block_group->flags);
2112         key.objectid = block_group->start;
2113         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2114         key.offset = block_group->length;
2115         spin_unlock(&block_group->lock);
2116
2117         root = fs_info->extent_root;
2118         return btrfs_insert_item(trans, root, &key, &bgi, sizeof(bgi));
2119 }
2120
2121 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
2122 {
2123         struct btrfs_fs_info *fs_info = trans->fs_info;
2124         struct btrfs_block_group *block_group;
2125         int ret = 0;
2126
2127         if (!trans->can_flush_pending_bgs)
2128                 return;
2129
2130         while (!list_empty(&trans->new_bgs)) {
2131                 int index;
2132
2133                 block_group = list_first_entry(&trans->new_bgs,
2134                                                struct btrfs_block_group,
2135                                                bg_list);
2136                 if (ret)
2137                         goto next;
2138
2139                 index = btrfs_bg_flags_to_raid_index(block_group->flags);
2140
2141                 ret = insert_block_group_item(trans, block_group);
2142                 if (ret)
2143                         btrfs_abort_transaction(trans, ret);
2144                 ret = btrfs_finish_chunk_alloc(trans, block_group->start,
2145                                         block_group->length);
2146                 if (ret)
2147                         btrfs_abort_transaction(trans, ret);
2148                 add_block_group_free_space(trans, block_group);
2149
2150                 /*
2151                  * If we restriped during balance, we may have added a new raid
2152                  * type, so now add the sysfs entries when it is safe to do so.
2153                  * We don't have to worry about locking here as it's handled in
2154                  * btrfs_sysfs_add_block_group_type.
2155                  */
2156                 if (block_group->space_info->block_group_kobjs[index] == NULL)
2157                         btrfs_sysfs_add_block_group_type(block_group);
2158
2159                 /* Already aborted the transaction if it failed. */
2160 next:
2161                 btrfs_delayed_refs_rsv_release(fs_info, 1);
2162                 list_del_init(&block_group->bg_list);
2163         }
2164         btrfs_trans_release_chunk_metadata(trans);
2165 }
2166
2167 int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
2168                            u64 type, u64 chunk_offset, u64 size)
2169 {
2170         struct btrfs_fs_info *fs_info = trans->fs_info;
2171         struct btrfs_block_group *cache;
2172         int ret;
2173
2174         btrfs_set_log_full_commit(trans);
2175
2176         cache = btrfs_create_block_group_cache(fs_info, chunk_offset);
2177         if (!cache)
2178                 return -ENOMEM;
2179
2180         cache->length = size;
2181         set_free_space_tree_thresholds(cache);
2182         cache->used = bytes_used;
2183         cache->flags = type;
2184         cache->last_byte_to_unpin = (u64)-1;
2185         cache->cached = BTRFS_CACHE_FINISHED;
2186         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
2187                 cache->needs_free_space = 1;
2188
2189         ret = btrfs_load_block_group_zone_info(cache, true);
2190         if (ret) {
2191                 btrfs_put_block_group(cache);
2192                 return ret;
2193         }
2194
2195         ret = exclude_super_stripes(cache);
2196         if (ret) {
2197                 /* We may have excluded something, so call this just in case */
2198                 btrfs_free_excluded_extents(cache);
2199                 btrfs_put_block_group(cache);
2200                 return ret;
2201         }
2202
2203         add_new_free_space(cache, chunk_offset, chunk_offset + size);
2204
2205         btrfs_free_excluded_extents(cache);
2206
2207 #ifdef CONFIG_BTRFS_DEBUG
2208         if (btrfs_should_fragment_free_space(cache)) {
2209                 u64 new_bytes_used = size - bytes_used;
2210
2211                 bytes_used += new_bytes_used >> 1;
2212                 fragment_free_space(cache);
2213         }
2214 #endif
2215         /*
2216          * Ensure the corresponding space_info object is created and
2217          * assigned to our block group. We want our bg to be added to the rbtree
2218          * with its ->space_info set.
2219          */
2220         cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
2221         ASSERT(cache->space_info);
2222
2223         ret = btrfs_add_block_group_cache(fs_info, cache);
2224         if (ret) {
2225                 btrfs_remove_free_space_cache(cache);
2226                 btrfs_put_block_group(cache);
2227                 return ret;
2228         }
2229
2230         /*
2231          * Now that our block group has its ->space_info set and is inserted in
2232          * the rbtree, update the space info's counters.
2233          */
2234         trace_btrfs_add_block_group(fs_info, cache, 1);
2235         btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
2236                                 cache->bytes_super, 0, &cache->space_info);
2237         btrfs_update_global_block_rsv(fs_info);
2238
2239         link_block_group(cache);
2240
2241         list_add_tail(&cache->bg_list, &trans->new_bgs);
2242         trans->delayed_ref_updates++;
2243         btrfs_update_delayed_refs_rsv(trans);
2244
2245         set_avail_alloc_bits(fs_info, type);
2246         return 0;
2247 }
2248
2249 /*
2250  * Mark one block group RO, can be called several times for the same block
2251  * group.
2252  *
2253  * @cache:              the destination block group
2254  * @do_chunk_alloc:     whether need to do chunk pre-allocation, this is to
2255  *                      ensure we still have some free space after marking this
2256  *                      block group RO.
2257  */
2258 int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
2259                              bool do_chunk_alloc)
2260 {
2261         struct btrfs_fs_info *fs_info = cache->fs_info;
2262         struct btrfs_trans_handle *trans;
2263         u64 alloc_flags;
2264         int ret;
2265
2266 again:
2267         trans = btrfs_join_transaction(fs_info->extent_root);
2268         if (IS_ERR(trans))
2269                 return PTR_ERR(trans);
2270
2271         /*
2272          * we're not allowed to set block groups readonly after the dirty
2273          * block groups cache has started writing.  If it already started,
2274          * back off and let this transaction commit
2275          */
2276         mutex_lock(&fs_info->ro_block_group_mutex);
2277         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
2278                 u64 transid = trans->transid;
2279
2280                 mutex_unlock(&fs_info->ro_block_group_mutex);
2281                 btrfs_end_transaction(trans);
2282
2283                 ret = btrfs_wait_for_commit(fs_info, transid);
2284                 if (ret)
2285                         return ret;
2286                 goto again;
2287         }
2288
2289         if (do_chunk_alloc) {
2290                 /*
2291                  * If we are changing raid levels, try to allocate a
2292                  * corresponding block group with the new raid level.
2293                  */
2294                 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2295                 if (alloc_flags != cache->flags) {
2296                         ret = btrfs_chunk_alloc(trans, alloc_flags,
2297                                                 CHUNK_ALLOC_FORCE);
2298                         /*
2299                          * ENOSPC is allowed here, we may have enough space
2300                          * already allocated at the new raid level to carry on
2301                          */
2302                         if (ret == -ENOSPC)
2303                                 ret = 0;
2304                         if (ret < 0)
2305                                 goto out;
2306                 }
2307         }
2308
2309         ret = inc_block_group_ro(cache, 0);
2310         if (!do_chunk_alloc)
2311                 goto unlock_out;
2312         if (!ret)
2313                 goto out;
2314         alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags);
2315         ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
2316         if (ret < 0)
2317                 goto out;
2318         ret = inc_block_group_ro(cache, 0);
2319 out:
2320         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2321                 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2322                 mutex_lock(&fs_info->chunk_mutex);
2323                 check_system_chunk(trans, alloc_flags);
2324                 mutex_unlock(&fs_info->chunk_mutex);
2325         }
2326 unlock_out:
2327         mutex_unlock(&fs_info->ro_block_group_mutex);
2328
2329         btrfs_end_transaction(trans);
2330         return ret;
2331 }
2332
2333 void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
2334 {
2335         struct btrfs_space_info *sinfo = cache->space_info;
2336         u64 num_bytes;
2337
2338         BUG_ON(!cache->ro);
2339
2340         spin_lock(&sinfo->lock);
2341         spin_lock(&cache->lock);
2342         if (!--cache->ro) {
2343                 num_bytes = cache->length - cache->reserved -
2344                             cache->pinned - cache->bytes_super -
2345                             cache->zone_unusable - cache->used;
2346                 sinfo->bytes_readonly -= num_bytes;
2347                 if (btrfs_is_zoned(cache->fs_info)) {
2348                         /* Migrate zone_unusable bytes back */
2349                         cache->zone_unusable = cache->alloc_offset - cache->used;
2350                         sinfo->bytes_zone_unusable += cache->zone_unusable;
2351                         sinfo->bytes_readonly -= cache->zone_unusable;
2352                 }
2353                 list_del_init(&cache->ro_list);
2354         }
2355         spin_unlock(&cache->lock);
2356         spin_unlock(&sinfo->lock);
2357 }
2358
2359 static int update_block_group_item(struct btrfs_trans_handle *trans,
2360                                    struct btrfs_path *path,
2361                                    struct btrfs_block_group *cache)
2362 {
2363         struct btrfs_fs_info *fs_info = trans->fs_info;
2364         int ret;
2365         struct btrfs_root *root = fs_info->extent_root;
2366         unsigned long bi;
2367         struct extent_buffer *leaf;
2368         struct btrfs_block_group_item bgi;
2369         struct btrfs_key key;
2370
2371         key.objectid = cache->start;
2372         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2373         key.offset = cache->length;
2374
2375         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2376         if (ret) {
2377                 if (ret > 0)
2378                         ret = -ENOENT;
2379                 goto fail;
2380         }
2381
2382         leaf = path->nodes[0];
2383         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2384         btrfs_set_stack_block_group_used(&bgi, cache->used);
2385         btrfs_set_stack_block_group_chunk_objectid(&bgi,
2386                         BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2387         btrfs_set_stack_block_group_flags(&bgi, cache->flags);
2388         write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));
2389         btrfs_mark_buffer_dirty(leaf);
2390 fail:
2391         btrfs_release_path(path);
2392         return ret;
2393
2394 }
2395
2396 static int cache_save_setup(struct btrfs_block_group *block_group,
2397                             struct btrfs_trans_handle *trans,
2398                             struct btrfs_path *path)
2399 {
2400         struct btrfs_fs_info *fs_info = block_group->fs_info;
2401         struct btrfs_root *root = fs_info->tree_root;
2402         struct inode *inode = NULL;
2403         struct extent_changeset *data_reserved = NULL;
2404         u64 alloc_hint = 0;
2405         int dcs = BTRFS_DC_ERROR;
2406         u64 num_pages = 0;
2407         int retries = 0;
2408         int ret = 0;
2409
2410         if (!btrfs_test_opt(fs_info, SPACE_CACHE))
2411                 return 0;
2412
2413         /*
2414          * If this block group is smaller than 100 megs don't bother caching the
2415          * block group.
2416          */
2417         if (block_group->length < (100 * SZ_1M)) {
2418                 spin_lock(&block_group->lock);
2419                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2420                 spin_unlock(&block_group->lock);
2421                 return 0;
2422         }
2423
2424         if (TRANS_ABORTED(trans))
2425                 return 0;
2426 again:
2427         inode = lookup_free_space_inode(block_group, path);
2428         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2429                 ret = PTR_ERR(inode);
2430                 btrfs_release_path(path);
2431                 goto out;
2432         }
2433
2434         if (IS_ERR(inode)) {
2435                 BUG_ON(retries);
2436                 retries++;
2437
2438                 if (block_group->ro)
2439                         goto out_free;
2440
2441                 ret = create_free_space_inode(trans, block_group, path);
2442                 if (ret)
2443                         goto out_free;
2444                 goto again;
2445         }
2446
2447         /*
2448          * We want to set the generation to 0, that way if anything goes wrong
2449          * from here on out we know not to trust this cache when we load up next
2450          * time.
2451          */
2452         BTRFS_I(inode)->generation = 0;
2453         ret = btrfs_update_inode(trans, root, BTRFS_I(inode));
2454         if (ret) {
2455                 /*
2456                  * So theoretically we could recover from this, simply set the
2457                  * super cache generation to 0 so we know to invalidate the
2458                  * cache, but then we'd have to keep track of the block groups
2459                  * that fail this way so we know we _have_ to reset this cache
2460                  * before the next commit or risk reading stale cache.  So to
2461                  * limit our exposure to horrible edge cases lets just abort the
2462                  * transaction, this only happens in really bad situations
2463                  * anyway.
2464                  */
2465                 btrfs_abort_transaction(trans, ret);
2466                 goto out_put;
2467         }
2468         WARN_ON(ret);
2469
2470         /* We've already setup this transaction, go ahead and exit */
2471         if (block_group->cache_generation == trans->transid &&
2472             i_size_read(inode)) {
2473                 dcs = BTRFS_DC_SETUP;
2474                 goto out_put;
2475         }
2476
2477         if (i_size_read(inode) > 0) {
2478                 ret = btrfs_check_trunc_cache_free_space(fs_info,
2479                                         &fs_info->global_block_rsv);
2480                 if (ret)
2481                         goto out_put;
2482
2483                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
2484                 if (ret)
2485                         goto out_put;
2486         }
2487
2488         spin_lock(&block_group->lock);
2489         if (block_group->cached != BTRFS_CACHE_FINISHED ||
2490             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
2491                 /*
2492                  * don't bother trying to write stuff out _if_
2493                  * a) we're not cached,
2494                  * b) we're with nospace_cache mount option,
2495                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
2496                  */
2497                 dcs = BTRFS_DC_WRITTEN;
2498                 spin_unlock(&block_group->lock);
2499                 goto out_put;
2500         }
2501         spin_unlock(&block_group->lock);
2502
2503         /*
2504          * We hit an ENOSPC when setting up the cache in this transaction, just
2505          * skip doing the setup, we've already cleared the cache so we're safe.
2506          */
2507         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
2508                 ret = -ENOSPC;
2509                 goto out_put;
2510         }
2511
2512         /*
2513          * Try to preallocate enough space based on how big the block group is.
2514          * Keep in mind this has to include any pinned space which could end up
2515          * taking up quite a bit since it's not folded into the other space
2516          * cache.
2517          */
2518         num_pages = div_u64(block_group->length, SZ_256M);
2519         if (!num_pages)
2520                 num_pages = 1;
2521
2522         num_pages *= 16;
2523         num_pages *= PAGE_SIZE;
2524
2525         ret = btrfs_check_data_free_space(BTRFS_I(inode), &data_reserved, 0,
2526                                           num_pages);
2527         if (ret)
2528                 goto out_put;
2529
2530         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2531                                               num_pages, num_pages,
2532                                               &alloc_hint);
2533         /*
2534          * Our cache requires contiguous chunks so that we don't modify a bunch
2535          * of metadata or split extents when writing the cache out, which means
2536          * we can enospc if we are heavily fragmented in addition to just normal
2537          * out of space conditions.  So if we hit this just skip setting up any
2538          * other block groups for this transaction, maybe we'll unpin enough
2539          * space the next time around.
2540          */
2541         if (!ret)
2542                 dcs = BTRFS_DC_SETUP;
2543         else if (ret == -ENOSPC)
2544                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
2545
2546 out_put:
2547         iput(inode);
2548 out_free:
2549         btrfs_release_path(path);
2550 out:
2551         spin_lock(&block_group->lock);
2552         if (!ret && dcs == BTRFS_DC_SETUP)
2553                 block_group->cache_generation = trans->transid;
2554         block_group->disk_cache_state = dcs;
2555         spin_unlock(&block_group->lock);
2556
2557         extent_changeset_free(data_reserved);
2558         return ret;
2559 }
2560
2561 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
2562 {
2563         struct btrfs_fs_info *fs_info = trans->fs_info;
2564         struct btrfs_block_group *cache, *tmp;
2565         struct btrfs_transaction *cur_trans = trans->transaction;
2566         struct btrfs_path *path;
2567
2568         if (list_empty(&cur_trans->dirty_bgs) ||
2569             !btrfs_test_opt(fs_info, SPACE_CACHE))
2570                 return 0;
2571
2572         path = btrfs_alloc_path();
2573         if (!path)
2574                 return -ENOMEM;
2575
2576         /* Could add new block groups, use _safe just in case */
2577         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
2578                                  dirty_list) {
2579                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2580                         cache_save_setup(cache, trans, path);
2581         }
2582
2583         btrfs_free_path(path);
2584         return 0;
2585 }
2586
2587 /*
2588  * Transaction commit does final block group cache writeback during a critical
2589  * section where nothing is allowed to change the FS.  This is required in
2590  * order for the cache to actually match the block group, but can introduce a
2591  * lot of latency into the commit.
2592  *
2593  * So, btrfs_start_dirty_block_groups is here to kick off block group cache IO.
2594  * There's a chance we'll have to redo some of it if the block group changes
2595  * again during the commit, but it greatly reduces the commit latency by
2596  * getting rid of the easy block groups while we're still allowing others to
2597  * join the commit.
2598  */
2599 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
2600 {
2601         struct btrfs_fs_info *fs_info = trans->fs_info;
2602         struct btrfs_block_group *cache;
2603         struct btrfs_transaction *cur_trans = trans->transaction;
2604         int ret = 0;
2605         int should_put;
2606         struct btrfs_path *path = NULL;
2607         LIST_HEAD(dirty);
2608         struct list_head *io = &cur_trans->io_bgs;
2609         int num_started = 0;
2610         int loops = 0;
2611
2612         spin_lock(&cur_trans->dirty_bgs_lock);
2613         if (list_empty(&cur_trans->dirty_bgs)) {
2614                 spin_unlock(&cur_trans->dirty_bgs_lock);
2615                 return 0;
2616         }
2617         list_splice_init(&cur_trans->dirty_bgs, &dirty);
2618         spin_unlock(&cur_trans->dirty_bgs_lock);
2619
2620 again:
2621         /* Make sure all the block groups on our dirty list actually exist */
2622         btrfs_create_pending_block_groups(trans);
2623
2624         if (!path) {
2625                 path = btrfs_alloc_path();
2626                 if (!path) {
2627                         ret = -ENOMEM;
2628                         goto out;
2629                 }
2630         }
2631
2632         /*
2633          * cache_write_mutex is here only to save us from balance or automatic
2634          * removal of empty block groups deleting this block group while we are
2635          * writing out the cache
2636          */
2637         mutex_lock(&trans->transaction->cache_write_mutex);
2638         while (!list_empty(&dirty)) {
2639                 bool drop_reserve = true;
2640
2641                 cache = list_first_entry(&dirty, struct btrfs_block_group,
2642                                          dirty_list);
2643                 /*
2644                  * This can happen if something re-dirties a block group that
2645                  * is already under IO.  Just wait for it to finish and then do
2646                  * it all again
2647                  */
2648                 if (!list_empty(&cache->io_list)) {
2649                         list_del_init(&cache->io_list);
2650                         btrfs_wait_cache_io(trans, cache, path);
2651                         btrfs_put_block_group(cache);
2652                 }
2653
2654
2655                 /*
2656                  * btrfs_wait_cache_io uses the cache->dirty_list to decide if
2657                  * it should update the cache_state.  Don't delete until after
2658                  * we wait.
2659                  *
2660                  * Since we're not running in the commit critical section
2661                  * we need the dirty_bgs_lock to protect from update_block_group
2662                  */
2663                 spin_lock(&cur_trans->dirty_bgs_lock);
2664                 list_del_init(&cache->dirty_list);
2665                 spin_unlock(&cur_trans->dirty_bgs_lock);
2666
2667                 should_put = 1;
2668
2669                 cache_save_setup(cache, trans, path);
2670
2671                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
2672                         cache->io_ctl.inode = NULL;
2673                         ret = btrfs_write_out_cache(trans, cache, path);
2674                         if (ret == 0 && cache->io_ctl.inode) {
2675                                 num_started++;
2676                                 should_put = 0;
2677
2678                                 /*
2679                                  * The cache_write_mutex is protecting the
2680                                  * io_list, also refer to the definition of
2681                                  * btrfs_transaction::io_bgs for more details
2682                                  */
2683                                 list_add_tail(&cache->io_list, io);
2684                         } else {
2685                                 /*
2686                                  * If we failed to write the cache, the
2687                                  * generation will be bad and life goes on
2688                                  */
2689                                 ret = 0;
2690                         }
2691                 }
2692                 if (!ret) {
2693                         ret = update_block_group_item(trans, path, cache);
2694                         /*
2695                          * Our block group might still be attached to the list
2696                          * of new block groups in the transaction handle of some
2697                          * other task (struct btrfs_trans_handle->new_bgs). This
2698                          * means its block group item isn't yet in the extent
2699                          * tree. If this happens ignore the error, as we will
2700                          * try again later in the critical section of the
2701                          * transaction commit.
2702                          */
2703                         if (ret == -ENOENT) {
2704                                 ret = 0;
2705                                 spin_lock(&cur_trans->dirty_bgs_lock);
2706                                 if (list_empty(&cache->dirty_list)) {
2707                                         list_add_tail(&cache->dirty_list,
2708                                                       &cur_trans->dirty_bgs);
2709                                         btrfs_get_block_group(cache);
2710                                         drop_reserve = false;
2711                                 }
2712                                 spin_unlock(&cur_trans->dirty_bgs_lock);
2713                         } else if (ret) {
2714                                 btrfs_abort_transaction(trans, ret);
2715                         }
2716                 }
2717
2718                 /* If it's not on the io list, we need to put the block group */
2719                 if (should_put)
2720                         btrfs_put_block_group(cache);
2721                 if (drop_reserve)
2722                         btrfs_delayed_refs_rsv_release(fs_info, 1);
2723                 /*
2724                  * Avoid blocking other tasks for too long. It might even save
2725                  * us from writing caches for block groups that are going to be
2726                  * removed.
2727                  */
2728                 mutex_unlock(&trans->transaction->cache_write_mutex);
2729                 if (ret)
2730                         goto out;
2731                 mutex_lock(&trans->transaction->cache_write_mutex);
2732         }
2733         mutex_unlock(&trans->transaction->cache_write_mutex);
2734
2735         /*
2736          * Go through delayed refs for all the stuff we've just kicked off
2737          * and then loop back (just once)
2738          */
2739         if (!ret)
2740                 ret = btrfs_run_delayed_refs(trans, 0);
2741         if (!ret && loops == 0) {
2742                 loops++;
2743                 spin_lock(&cur_trans->dirty_bgs_lock);
2744                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
2745                 /*
2746                  * dirty_bgs_lock protects us from concurrent block group
2747                  * deletes too (not just cache_write_mutex).
2748                  */
2749                 if (!list_empty(&dirty)) {
2750                         spin_unlock(&cur_trans->dirty_bgs_lock);
2751                         goto again;
2752                 }
2753                 spin_unlock(&cur_trans->dirty_bgs_lock);
2754         }
2755 out:
2756         if (ret < 0) {
2757                 spin_lock(&cur_trans->dirty_bgs_lock);
2758                 list_splice_init(&dirty, &cur_trans->dirty_bgs);
2759                 spin_unlock(&cur_trans->dirty_bgs_lock);
2760                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
2761         }
2762
2763         btrfs_free_path(path);
2764         return ret;
2765 }
2766
2767 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
2768 {
2769         struct btrfs_fs_info *fs_info = trans->fs_info;
2770         struct btrfs_block_group *cache;
2771         struct btrfs_transaction *cur_trans = trans->transaction;
2772         int ret = 0;
2773         int should_put;
2774         struct btrfs_path *path;
2775         struct list_head *io = &cur_trans->io_bgs;
2776         int num_started = 0;
2777
2778         path = btrfs_alloc_path();
2779         if (!path)
2780                 return -ENOMEM;
2781
2782         /*
2783          * Even though we are in the critical section of the transaction commit,
2784          * we can still have concurrent tasks adding elements to this
2785          * transaction's list of dirty block groups. These tasks correspond to
2786          * endio free space workers started when writeback finishes for a
2787          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
2788          * allocate new block groups as a result of COWing nodes of the root
2789          * tree when updating the free space inode. The writeback for the space
2790          * caches is triggered by an earlier call to
2791          * btrfs_start_dirty_block_groups() and iterations of the following
2792          * loop.
2793          * Also we want to do the cache_save_setup first and then run the
2794          * delayed refs to make sure we have the best chance at doing this all
2795          * in one shot.
2796          */
2797         spin_lock(&cur_trans->dirty_bgs_lock);
2798         while (!list_empty(&cur_trans->dirty_bgs)) {
2799                 cache = list_first_entry(&cur_trans->dirty_bgs,
2800                                          struct btrfs_block_group,
2801                                          dirty_list);
2802
2803                 /*
2804                  * This can happen if cache_save_setup re-dirties a block group
2805                  * that is already under IO.  Just wait for it to finish and
2806                  * then do it all again
2807                  */
2808                 if (!list_empty(&cache->io_list)) {
2809                         spin_unlock(&cur_trans->dirty_bgs_lock);
2810                         list_del_init(&cache->io_list);
2811                         btrfs_wait_cache_io(trans, cache, path);
2812                         btrfs_put_block_group(cache);
2813                         spin_lock(&cur_trans->dirty_bgs_lock);
2814                 }
2815
2816                 /*
2817                  * Don't remove from the dirty list until after we've waited on
2818                  * any pending IO
2819                  */
2820                 list_del_init(&cache->dirty_list);
2821                 spin_unlock(&cur_trans->dirty_bgs_lock);
2822                 should_put = 1;
2823
2824                 cache_save_setup(cache, trans, path);
2825
2826                 if (!ret)
2827                         ret = btrfs_run_delayed_refs(trans,
2828                                                      (unsigned long) -1);
2829
2830                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
2831                         cache->io_ctl.inode = NULL;
2832                         ret = btrfs_write_out_cache(trans, cache, path);
2833                         if (ret == 0 && cache->io_ctl.inode) {
2834                                 num_started++;
2835                                 should_put = 0;
2836                                 list_add_tail(&cache->io_list, io);
2837                         } else {
2838                                 /*
2839                                  * If we failed to write the cache, the
2840                                  * generation will be bad and life goes on
2841                                  */
2842                                 ret = 0;
2843                         }
2844                 }
2845                 if (!ret) {
2846                         ret = update_block_group_item(trans, path, cache);
2847                         /*
2848                          * One of the free space endio workers might have
2849                          * created a new block group while updating a free space
2850                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
2851                          * and hasn't released its transaction handle yet, in
2852                          * which case the new block group is still attached to
2853                          * its transaction handle and its creation has not
2854                          * finished yet (no block group item in the extent tree
2855                          * yet, etc). If this is the case, wait for all free
2856                          * space endio workers to finish and retry. This is a
2857                          * very rare case so no need for a more efficient and
2858                          * complex approach.
2859                          */
2860                         if (ret == -ENOENT) {
2861                                 wait_event(cur_trans->writer_wait,
2862                                    atomic_read(&cur_trans->num_writers) == 1);
2863                                 ret = update_block_group_item(trans, path, cache);
2864                         }
2865                         if (ret)
2866                                 btrfs_abort_transaction(trans, ret);
2867                 }
2868
2869                 /* If its not on the io list, we need to put the block group */
2870                 if (should_put)
2871                         btrfs_put_block_group(cache);
2872                 btrfs_delayed_refs_rsv_release(fs_info, 1);
2873                 spin_lock(&cur_trans->dirty_bgs_lock);
2874         }
2875         spin_unlock(&cur_trans->dirty_bgs_lock);
2876
2877         /*
2878          * Refer to the definition of io_bgs member for details why it's safe
2879          * to use it without any locking
2880          */
2881         while (!list_empty(io)) {
2882                 cache = list_first_entry(io, struct btrfs_block_group,
2883                                          io_list);
2884                 list_del_init(&cache->io_list);
2885                 btrfs_wait_cache_io(trans, cache, path);
2886                 btrfs_put_block_group(cache);
2887         }
2888
2889         btrfs_free_path(path);
2890         return ret;
2891 }
2892
2893 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
2894                              u64 bytenr, u64 num_bytes, int alloc)
2895 {
2896         struct btrfs_fs_info *info = trans->fs_info;
2897         struct btrfs_block_group *cache = NULL;
2898         u64 total = num_bytes;
2899         u64 old_val;
2900         u64 byte_in_group;
2901         int factor;
2902         int ret = 0;
2903
2904         /* Block accounting for super block */
2905         spin_lock(&info->delalloc_root_lock);
2906         old_val = btrfs_super_bytes_used(info->super_copy);
2907         if (alloc)
2908                 old_val += num_bytes;
2909         else
2910                 old_val -= num_bytes;
2911         btrfs_set_super_bytes_used(info->super_copy, old_val);
2912         spin_unlock(&info->delalloc_root_lock);
2913
2914         while (total) {
2915                 cache = btrfs_lookup_block_group(info, bytenr);
2916                 if (!cache) {
2917                         ret = -ENOENT;
2918                         break;
2919                 }
2920                 factor = btrfs_bg_type_to_factor(cache->flags);
2921
2922                 /*
2923                  * If this block group has free space cache written out, we
2924                  * need to make sure to load it if we are removing space.  This
2925                  * is because we need the unpinning stage to actually add the
2926                  * space back to the block group, otherwise we will leak space.
2927                  */
2928                 if (!alloc && !btrfs_block_group_done(cache))
2929                         btrfs_cache_block_group(cache, 1);
2930
2931                 byte_in_group = bytenr - cache->start;
2932                 WARN_ON(byte_in_group > cache->length);
2933
2934                 spin_lock(&cache->space_info->lock);
2935                 spin_lock(&cache->lock);
2936
2937                 if (btrfs_test_opt(info, SPACE_CACHE) &&
2938                     cache->disk_cache_state < BTRFS_DC_CLEAR)
2939                         cache->disk_cache_state = BTRFS_DC_CLEAR;
2940
2941                 old_val = cache->used;
2942                 num_bytes = min(total, cache->length - byte_in_group);
2943                 if (alloc) {
2944                         old_val += num_bytes;
2945                         cache->used = old_val;
2946                         cache->reserved -= num_bytes;
2947                         cache->space_info->bytes_reserved -= num_bytes;
2948                         cache->space_info->bytes_used += num_bytes;
2949                         cache->space_info->disk_used += num_bytes * factor;
2950                         spin_unlock(&cache->lock);
2951                         spin_unlock(&cache->space_info->lock);
2952                 } else {
2953                         old_val -= num_bytes;
2954                         cache->used = old_val;
2955                         cache->pinned += num_bytes;
2956                         btrfs_space_info_update_bytes_pinned(info,
2957                                         cache->space_info, num_bytes);
2958                         cache->space_info->bytes_used -= num_bytes;
2959                         cache->space_info->disk_used -= num_bytes * factor;
2960                         spin_unlock(&cache->lock);
2961                         spin_unlock(&cache->space_info->lock);
2962
2963                         __btrfs_mod_total_bytes_pinned(cache->space_info,
2964                                                        num_bytes);
2965                         set_extent_dirty(&trans->transaction->pinned_extents,
2966                                          bytenr, bytenr + num_bytes - 1,
2967                                          GFP_NOFS | __GFP_NOFAIL);
2968                 }
2969
2970                 spin_lock(&trans->transaction->dirty_bgs_lock);
2971                 if (list_empty(&cache->dirty_list)) {
2972                         list_add_tail(&cache->dirty_list,
2973                                       &trans->transaction->dirty_bgs);
2974                         trans->delayed_ref_updates++;
2975                         btrfs_get_block_group(cache);
2976                 }
2977                 spin_unlock(&trans->transaction->dirty_bgs_lock);
2978
2979                 /*
2980                  * No longer have used bytes in this block group, queue it for
2981                  * deletion. We do this after adding the block group to the
2982                  * dirty list to avoid races between cleaner kthread and space
2983                  * cache writeout.
2984                  */
2985                 if (!alloc && old_val == 0) {
2986                         if (!btrfs_test_opt(info, DISCARD_ASYNC))
2987                                 btrfs_mark_bg_unused(cache);
2988                 }
2989
2990                 btrfs_put_block_group(cache);
2991                 total -= num_bytes;
2992                 bytenr += num_bytes;
2993         }
2994
2995         /* Modified block groups are accounted for in the delayed_refs_rsv. */
2996         btrfs_update_delayed_refs_rsv(trans);
2997         return ret;
2998 }
2999
3000 /**
3001  * btrfs_add_reserved_bytes - update the block_group and space info counters
3002  * @cache:      The cache we are manipulating
3003  * @ram_bytes:  The number of bytes of file content, and will be same to
3004  *              @num_bytes except for the compress path.
3005  * @num_bytes:  The number of bytes in question
3006  * @delalloc:   The blocks are allocated for the delalloc write
3007  *
3008  * This is called by the allocator when it reserves space. If this is a
3009  * reservation and the block group has become read only we cannot make the
3010  * reservation and return -EAGAIN, otherwise this function always succeeds.
3011  */
3012 int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
3013                              u64 ram_bytes, u64 num_bytes, int delalloc)
3014 {
3015         struct btrfs_space_info *space_info = cache->space_info;
3016         int ret = 0;
3017
3018         spin_lock(&space_info->lock);
3019         spin_lock(&cache->lock);
3020         if (cache->ro) {
3021                 ret = -EAGAIN;
3022         } else {
3023                 cache->reserved += num_bytes;
3024                 space_info->bytes_reserved += num_bytes;
3025                 trace_btrfs_space_reservation(cache->fs_info, "space_info",
3026                                               space_info->flags, num_bytes, 1);
3027                 btrfs_space_info_update_bytes_may_use(cache->fs_info,
3028                                                       space_info, -ram_bytes);
3029                 if (delalloc)
3030                         cache->delalloc_bytes += num_bytes;
3031
3032                 /*
3033                  * Compression can use less space than we reserved, so wake
3034                  * tickets if that happens
3035                  */
3036                 if (num_bytes < ram_bytes)
3037                         btrfs_try_granting_tickets(cache->fs_info, space_info);
3038         }
3039         spin_unlock(&cache->lock);
3040         spin_unlock(&space_info->lock);
3041         return ret;
3042 }
3043
3044 /**
3045  * btrfs_free_reserved_bytes - update the block_group and space info counters
3046  * @cache:      The cache we are manipulating
3047  * @num_bytes:  The number of bytes in question
3048  * @delalloc:   The blocks are allocated for the delalloc write
3049  *
3050  * This is called by somebody who is freeing space that was never actually used
3051  * on disk.  For example if you reserve some space for a new leaf in transaction
3052  * A and before transaction A commits you free that leaf, you call this with
3053  * reserve set to 0 in order to clear the reservation.
3054  */
3055 void btrfs_free_reserved_bytes(struct btrfs_block_group *cache,
3056                                u64 num_bytes, int delalloc)
3057 {
3058         struct btrfs_space_info *space_info = cache->space_info;
3059
3060         spin_lock(&space_info->lock);
3061         spin_lock(&cache->lock);
3062         if (cache->ro)
3063                 space_info->bytes_readonly += num_bytes;
3064         cache->reserved -= num_bytes;
3065         space_info->bytes_reserved -= num_bytes;
3066         space_info->max_extent_size = 0;
3067
3068         if (delalloc)
3069                 cache->delalloc_bytes -= num_bytes;
3070         spin_unlock(&cache->lock);
3071
3072         btrfs_try_granting_tickets(cache->fs_info, space_info);
3073         spin_unlock(&space_info->lock);
3074 }
3075
3076 static void force_metadata_allocation(struct btrfs_fs_info *info)
3077 {
3078         struct list_head *head = &info->space_info;
3079         struct btrfs_space_info *found;
3080
3081         list_for_each_entry(found, head, list) {
3082                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3083                         found->force_alloc = CHUNK_ALLOC_FORCE;
3084         }
3085 }
3086
3087 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
3088                               struct btrfs_space_info *sinfo, int force)
3089 {
3090         u64 bytes_used = btrfs_space_info_used(sinfo, false);
3091         u64 thresh;
3092
3093         if (force == CHUNK_ALLOC_FORCE)
3094                 return 1;
3095
3096         /*
3097          * in limited mode, we want to have some free space up to
3098          * about 1% of the FS size.
3099          */
3100         if (force == CHUNK_ALLOC_LIMITED) {
3101                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
3102                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
3103
3104                 if (sinfo->total_bytes - bytes_used < thresh)
3105                         return 1;
3106         }
3107
3108         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
3109                 return 0;
3110         return 1;
3111 }
3112
3113 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
3114 {
3115         u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type);
3116
3117         return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
3118 }
3119
3120 /*
3121  * If force is CHUNK_ALLOC_FORCE:
3122  *    - return 1 if it successfully allocates a chunk,
3123  *    - return errors including -ENOSPC otherwise.
3124  * If force is NOT CHUNK_ALLOC_FORCE:
3125  *    - return 0 if it doesn't need to allocate a new chunk,
3126  *    - return 1 if it successfully allocates a chunk,
3127  *    - return errors including -ENOSPC otherwise.
3128  */
3129 int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
3130                       enum btrfs_chunk_alloc_enum force)
3131 {
3132         struct btrfs_fs_info *fs_info = trans->fs_info;
3133         struct btrfs_space_info *space_info;
3134         bool wait_for_alloc = false;
3135         bool should_alloc = false;
3136         int ret = 0;
3137
3138         /* Don't re-enter if we're already allocating a chunk */
3139         if (trans->allocating_chunk)
3140                 return -ENOSPC;
3141
3142         space_info = btrfs_find_space_info(fs_info, flags);
3143         ASSERT(space_info);
3144
3145         do {
3146                 spin_lock(&space_info->lock);
3147                 if (force < space_info->force_alloc)
3148                         force = space_info->force_alloc;
3149                 should_alloc = should_alloc_chunk(fs_info, space_info, force);
3150                 if (space_info->full) {
3151                         /* No more free physical space */
3152                         if (should_alloc)
3153                                 ret = -ENOSPC;
3154                         else
3155                                 ret = 0;
3156                         spin_unlock(&space_info->lock);
3157                         return ret;
3158                 } else if (!should_alloc) {
3159                         spin_unlock(&space_info->lock);
3160                         return 0;
3161                 } else if (space_info->chunk_alloc) {
3162                         /*
3163                          * Someone is already allocating, so we need to block
3164                          * until this someone is finished and then loop to
3165                          * recheck if we should continue with our allocation
3166                          * attempt.
3167                          */
3168                         wait_for_alloc = true;
3169                         spin_unlock(&space_info->lock);
3170                         mutex_lock(&fs_info->chunk_mutex);
3171                         mutex_unlock(&fs_info->chunk_mutex);
3172                 } else {
3173                         /* Proceed with allocation */
3174                         space_info->chunk_alloc = 1;
3175                         wait_for_alloc = false;
3176                         spin_unlock(&space_info->lock);
3177                 }
3178
3179                 cond_resched();
3180         } while (wait_for_alloc);
3181
3182         mutex_lock(&fs_info->chunk_mutex);
3183         trans->allocating_chunk = true;
3184
3185         /*
3186          * If we have mixed data/metadata chunks we want to make sure we keep
3187          * allocating mixed chunks instead of individual chunks.
3188          */
3189         if (btrfs_mixed_space_info(space_info))
3190                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3191
3192         /*
3193          * if we're doing a data chunk, go ahead and make sure that
3194          * we keep a reasonable number of metadata chunks allocated in the
3195          * FS as well.
3196          */
3197         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3198                 fs_info->data_chunk_allocations++;
3199                 if (!(fs_info->data_chunk_allocations %
3200                       fs_info->metadata_ratio))
3201                         force_metadata_allocation(fs_info);
3202         }
3203
3204         /*
3205          * Check if we have enough space in SYSTEM chunk because we may need
3206          * to update devices.
3207          */
3208         check_system_chunk(trans, flags);
3209
3210         ret = btrfs_alloc_chunk(trans, flags);
3211         trans->allocating_chunk = false;
3212
3213         spin_lock(&space_info->lock);
3214         if (ret < 0) {
3215                 if (ret == -ENOSPC)
3216                         space_info->full = 1;
3217                 else
3218                         goto out;
3219         } else {
3220                 ret = 1;
3221                 space_info->max_extent_size = 0;
3222         }
3223
3224         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3225 out:
3226         space_info->chunk_alloc = 0;
3227         spin_unlock(&space_info->lock);
3228         mutex_unlock(&fs_info->chunk_mutex);
3229         /*
3230          * When we allocate a new chunk we reserve space in the chunk block
3231          * reserve to make sure we can COW nodes/leafs in the chunk tree or
3232          * add new nodes/leafs to it if we end up needing to do it when
3233          * inserting the chunk item and updating device items as part of the
3234          * second phase of chunk allocation, performed by
3235          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
3236          * large number of new block groups to create in our transaction
3237          * handle's new_bgs list to avoid exhausting the chunk block reserve
3238          * in extreme cases - like having a single transaction create many new
3239          * block groups when starting to write out the free space caches of all
3240          * the block groups that were made dirty during the lifetime of the
3241          * transaction.
3242          */
3243         if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
3244                 btrfs_create_pending_block_groups(trans);
3245
3246         return ret;
3247 }
3248
3249 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
3250 {
3251         u64 num_dev;
3252
3253         num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
3254         if (!num_dev)
3255                 num_dev = fs_info->fs_devices->rw_devices;
3256
3257         return num_dev;
3258 }
3259
3260 /*
3261  * Reserve space in the system space for allocating or removing a chunk
3262  */
3263 void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
3264 {
3265         struct btrfs_fs_info *fs_info = trans->fs_info;
3266         struct btrfs_space_info *info;
3267         u64 left;
3268         u64 thresh;
3269         int ret = 0;
3270         u64 num_devs;
3271
3272         /*
3273          * Needed because we can end up allocating a system chunk and for an
3274          * atomic and race free space reservation in the chunk block reserve.
3275          */
3276         lockdep_assert_held(&fs_info->chunk_mutex);
3277
3278         info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3279         spin_lock(&info->lock);
3280         left = info->total_bytes - btrfs_space_info_used(info, true);
3281         spin_unlock(&info->lock);
3282
3283         num_devs = get_profile_num_devs(fs_info, type);
3284
3285         /* num_devs device items to update and 1 chunk item to add or remove */
3286         thresh = btrfs_calc_metadata_size(fs_info, num_devs) +
3287                 btrfs_calc_insert_metadata_size(fs_info, 1);
3288
3289         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
3290                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
3291                            left, thresh, type);
3292                 btrfs_dump_space_info(fs_info, info, 0, 0);
3293         }
3294
3295         if (left < thresh) {
3296                 u64 flags = btrfs_system_alloc_profile(fs_info);
3297
3298                 /*
3299                  * Ignore failure to create system chunk. We might end up not
3300                  * needing it, as we might not need to COW all nodes/leafs from
3301                  * the paths we visit in the chunk tree (they were already COWed
3302                  * or created in the current transaction for example).
3303                  */
3304                 ret = btrfs_alloc_chunk(trans, flags);
3305         }
3306
3307         if (!ret) {
3308                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
3309                                           &fs_info->chunk_block_rsv,
3310                                           thresh, BTRFS_RESERVE_NO_FLUSH);
3311                 if (!ret)
3312                         trans->chunk_bytes_reserved += thresh;
3313         }
3314 }
3315
3316 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
3317 {
3318         struct btrfs_block_group *block_group;
3319         u64 last = 0;
3320
3321         while (1) {
3322                 struct inode *inode;
3323
3324                 block_group = btrfs_lookup_first_block_group(info, last);
3325                 while (block_group) {
3326                         btrfs_wait_block_group_cache_done(block_group);
3327                         spin_lock(&block_group->lock);
3328                         if (block_group->iref)
3329                                 break;
3330                         spin_unlock(&block_group->lock);
3331                         block_group = btrfs_next_block_group(block_group);
3332                 }
3333                 if (!block_group) {
3334                         if (last == 0)
3335                                 break;
3336                         last = 0;
3337                         continue;
3338                 }
3339
3340                 inode = block_group->inode;
3341                 block_group->iref = 0;
3342                 block_group->inode = NULL;
3343                 spin_unlock(&block_group->lock);
3344                 ASSERT(block_group->io_ctl.inode == NULL);
3345                 iput(inode);
3346                 last = block_group->start + block_group->length;
3347                 btrfs_put_block_group(block_group);
3348         }
3349 }
3350
3351 /*
3352  * Must be called only after stopping all workers, since we could have block
3353  * group caching kthreads running, and therefore they could race with us if we
3354  * freed the block groups before stopping them.
3355  */
3356 int btrfs_free_block_groups(struct btrfs_fs_info *info)
3357 {
3358         struct btrfs_block_group *block_group;
3359         struct btrfs_space_info *space_info;
3360         struct btrfs_caching_control *caching_ctl;
3361         struct rb_node *n;
3362
3363         spin_lock(&info->block_group_cache_lock);
3364         while (!list_empty(&info->caching_block_groups)) {
3365                 caching_ctl = list_entry(info->caching_block_groups.next,
3366                                          struct btrfs_caching_control, list);
3367                 list_del(&caching_ctl->list);
3368                 btrfs_put_caching_control(caching_ctl);
3369         }
3370         spin_unlock(&info->block_group_cache_lock);
3371
3372         spin_lock(&info->unused_bgs_lock);
3373         while (!list_empty(&info->unused_bgs)) {
3374                 block_group = list_first_entry(&info->unused_bgs,
3375                                                struct btrfs_block_group,
3376                                                bg_list);
3377                 list_del_init(&block_group->bg_list);
3378                 btrfs_put_block_group(block_group);
3379         }
3380         spin_unlock(&info->unused_bgs_lock);
3381
3382         spin_lock(&info->block_group_cache_lock);
3383         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
3384                 block_group = rb_entry(n, struct btrfs_block_group,
3385                                        cache_node);
3386                 rb_erase(&block_group->cache_node,
3387                          &info->block_group_cache_tree);
3388                 RB_CLEAR_NODE(&block_group->cache_node);
3389                 spin_unlock(&info->block_group_cache_lock);
3390
3391                 down_write(&block_group->space_info->groups_sem);
3392                 list_del(&block_group->list);
3393                 up_write(&block_group->space_info->groups_sem);
3394
3395                 /*
3396                  * We haven't cached this block group, which means we could
3397                  * possibly have excluded extents on this block group.
3398                  */
3399                 if (block_group->cached == BTRFS_CACHE_NO ||
3400                     block_group->cached == BTRFS_CACHE_ERROR)
3401                         btrfs_free_excluded_extents(block_group);
3402
3403                 btrfs_remove_free_space_cache(block_group);
3404                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
3405                 ASSERT(list_empty(&block_group->dirty_list));
3406                 ASSERT(list_empty(&block_group->io_list));
3407                 ASSERT(list_empty(&block_group->bg_list));
3408                 ASSERT(refcount_read(&block_group->refs) == 1);
3409                 btrfs_put_block_group(block_group);
3410
3411                 spin_lock(&info->block_group_cache_lock);
3412         }
3413         spin_unlock(&info->block_group_cache_lock);
3414
3415         btrfs_release_global_block_rsv(info);
3416
3417         while (!list_empty(&info->space_info)) {
3418                 space_info = list_entry(info->space_info.next,
3419                                         struct btrfs_space_info,
3420                                         list);
3421
3422                 /*
3423                  * Do not hide this behind enospc_debug, this is actually
3424                  * important and indicates a real bug if this happens.
3425                  */
3426                 if (WARN_ON(space_info->bytes_pinned > 0 ||
3427                             space_info->bytes_reserved > 0 ||
3428                             space_info->bytes_may_use > 0))
3429                         btrfs_dump_space_info(info, space_info, 0, 0);
3430                 WARN_ON(space_info->reclaim_size > 0);
3431                 list_del(&space_info->list);
3432                 btrfs_sysfs_remove_space_info(space_info);
3433         }
3434         return 0;
3435 }
3436
3437 void btrfs_freeze_block_group(struct btrfs_block_group *cache)
3438 {
3439         atomic_inc(&cache->frozen);
3440 }
3441
3442 void btrfs_unfreeze_block_group(struct btrfs_block_group *block_group)
3443 {
3444         struct btrfs_fs_info *fs_info = block_group->fs_info;
3445         struct extent_map_tree *em_tree;
3446         struct extent_map *em;
3447         bool cleanup;
3448
3449         spin_lock(&block_group->lock);
3450         cleanup = (atomic_dec_and_test(&block_group->frozen) &&
3451                    block_group->removed);
3452         spin_unlock(&block_group->lock);
3453
3454         if (cleanup) {
3455                 em_tree = &fs_info->mapping_tree;
3456                 write_lock(&em_tree->lock);
3457                 em = lookup_extent_mapping(em_tree, block_group->start,
3458                                            1);
3459                 BUG_ON(!em); /* logic error, can't happen */
3460                 remove_extent_mapping(em_tree, em);
3461                 write_unlock(&em_tree->lock);
3462
3463                 /* once for us and once for the tree */
3464                 free_extent_map(em);
3465                 free_extent_map(em);
3466
3467                 /*
3468                  * We may have left one free space entry and other possible
3469                  * tasks trimming this block group have left 1 entry each one.
3470                  * Free them if any.
3471                  */
3472                 __btrfs_remove_free_space_cache(block_group->free_space_ctl);
3473         }
3474 }