fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/percpu_counter.h>
  28 #include "hash.h"
  29 #include "tree-log.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "volumes.h"
  33 #include "raid56.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36 #include "math.h"
  37 #include "sysfs.h"
  38 #include "qgroup.h"
  39
  40 #undef SCRAMBLE_DELAYED_REFS
  41
  42 /*
  43  * control flags for do_chunk_alloc's force field
  44  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  45  * if we really need one.
  46  *
  47  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  48  * if we have very few chunks already allocated.  This is
  49  * used as part of the clustering code to help make sure
  50  * we have a good pool of storage to cluster in, without
  51  * filling the FS with empty chunks
  52  *
  53  * CHUNK_ALLOC_FORCE means it must try to allocate one
  54  *
  55  */
  56 enum {
  57         CHUNK_ALLOC_NO_FORCE = 0,
  58         CHUNK_ALLOC_LIMITED = 1,
  59         CHUNK_ALLOC_FORCE = 2,
  60 };
  61
  62 /*
  63  * Control how reservations are dealt with.
  64  *
  65  * RESERVE_FREE - freeing a reservation.
  66  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  67  *   ENOSPC accounting
  68  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  69  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  70  */
  71 enum {
  72         RESERVE_FREE = 0,
  73         RESERVE_ALLOC = 1,
  74         RESERVE_ALLOC_NO_ACCOUNT = 2,
  75 };
  76
  77 static int update_block_group(struct btrfs_trans_handle *trans,
  78                               struct btrfs_root *root, u64 bytenr,
  79                               u64 num_bytes, int alloc);
  80 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  81                                 struct btrfs_root *root,
  82                                 struct btrfs_delayed_ref_node *node, u64 parent,
  83                                 u64 root_objectid, u64 owner_objectid,
  84                                 u64 owner_offset, int refs_to_drop,
  85                                 struct btrfs_delayed_extent_op *extra_op);
  86 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  87                                     struct extent_buffer *leaf,
  88                                     struct btrfs_extent_item *ei);
  89 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  90                                       struct btrfs_root *root,
  91                                       u64 parent, u64 root_objectid,
  92                                       u64 flags, u64 owner, u64 offset,
  93                                       struct btrfs_key *ins, int ref_mod);
  94 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  95                                      struct btrfs_root *root,
  96                                      u64 parent, u64 root_objectid,
  97                                      u64 flags, struct btrfs_disk_key *key,
  98                                      int level, struct btrfs_key *ins,
  99                                      int no_quota);
 100 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 101                           struct btrfs_root *extent_root, u64 flags,
 102                           int force);
 103 static int find_next_key(struct btrfs_path *path, int level,
 104                          struct btrfs_key *key);
 105 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 106                             int dump_block_groups);
 107 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 108                                        u64 num_bytes, int reserve,
 109                                        int delalloc);
 110 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 111                                u64 num_bytes);
 112 int btrfs_pin_extent(struct btrfs_root *root,
 113                      u64 bytenr, u64 num_bytes, int reserved);
 114
 115 static noinline int
 116 block_group_cache_done(struct btrfs_block_group_cache *cache)
 117 {
 118         smp_mb();
 119         return cache->cached == BTRFS_CACHE_FINISHED ||
 120                 cache->cached == BTRFS_CACHE_ERROR;
 121 }
 122
 123 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 124 {
 125         return (cache->flags & bits) == bits;
 126 }
 127
 128 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 129 {
 130         atomic_inc(&cache->count);
 131 }
 132
 133 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 134 {
 135         if (atomic_dec_and_test(&cache->count)) {
 136                 WARN_ON(cache->pinned > 0);
 137                 WARN_ON(cache->reserved > 0);
 138                 kfree(cache->free_space_ctl);
 139                 kfree(cache);
 140         }
 141 }
 142
 143 /*
 144  * this adds the block group to the fs_info rb tree for the block group
 145  * cache
 146  */
 147 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 148                                 struct btrfs_block_group_cache *block_group)
 149 {
 150         struct rb_node **p;
 151         struct rb_node *parent = NULL;
 152         struct btrfs_block_group_cache *cache;
 153
 154         spin_lock(&info->block_group_cache_lock);
 155         p = &info->block_group_cache_tree.rb_node;
 156
 157         while (*p) {
 158                 parent = *p;
 159                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 160                                  cache_node);
 161                 if (block_group->key.objectid < cache->key.objectid) {
 162                         p = &(*p)->rb_left;
 163                 } else if (block_group->key.objectid > cache->key.objectid) {
 164                         p = &(*p)->rb_right;
 165                 } else {
 166                         spin_unlock(&info->block_group_cache_lock);
 167                         return -EEXIST;
 168                 }
 169         }
 170
 171         rb_link_node(&block_group->cache_node, parent, p);
 172         rb_insert_color(&block_group->cache_node,
 173                         &info->block_group_cache_tree);
 174
 175         if (info->first_logical_byte > block_group->key.objectid)
 176                 info->first_logical_byte = block_group->key.objectid;
 177
 178         spin_unlock(&info->block_group_cache_lock);
 179
 180         return 0;
 181 }
 182
 183 /*
 184  * This will return the block group at or after bytenr if contains is 0, else
 185  * it will return the block group that contains the bytenr
 186  */
 187 static struct btrfs_block_group_cache *
 188 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 189                               int contains)
 190 {
 191         struct btrfs_block_group_cache *cache, *ret = NULL;
 192         struct rb_node *n;
 193         u64 end, start;
 194
 195         spin_lock(&info->block_group_cache_lock);
 196         n = info->block_group_cache_tree.rb_node;
 197
 198         while (n) {
 199                 cache = rb_entry(n, struct btrfs_block_group_cache,
 200                                  cache_node);
 201                 end = cache->key.objectid + cache->key.offset - 1;
 202                 start = cache->key.objectid;
 203
 204                 if (bytenr < start) {
 205                         if (!contains && (!ret || start < ret->key.objectid))
 206                                 ret = cache;
 207                         n = n->rb_left;
 208                 } else if (bytenr > start) {
 209                         if (contains && bytenr <= end) {
 210                                 ret = cache;
 211                                 break;
 212                         }
 213                         n = n->rb_right;
 214                 } else {
 215                         ret = cache;
 216                         break;
 217                 }
 218         }
 219         if (ret) {
 220                 btrfs_get_block_group(ret);
 221                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 222                         info->first_logical_byte = ret->key.objectid;
 223         }
 224         spin_unlock(&info->block_group_cache_lock);
 225
 226         return ret;
 227 }
 228
 229 static int add_excluded_extent(struct btrfs_root *root,
 230                                u64 start, u64 num_bytes)
 231 {
 232         u64 end = start + num_bytes - 1;
 233         set_extent_bits(&root->fs_info->freed_extents[0],
 234                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 235         set_extent_bits(&root->fs_info->freed_extents[1],
 236                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 237         return 0;
 238 }
 239
 240 static void free_excluded_extents(struct btrfs_root *root,
 241                                   struct btrfs_block_group_cache *cache)
 242 {
 243         u64 start, end;
 244
 245         start = cache->key.objectid;
 246         end = start + cache->key.offset - 1;
 247
 248         clear_extent_bits(&root->fs_info->freed_extents[0],
 249                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 250         clear_extent_bits(&root->fs_info->freed_extents[1],
 251                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 252 }
 253
 254 static int exclude_super_stripes(struct btrfs_root *root,
 255                                  struct btrfs_block_group_cache *cache)
 256 {
 257         u64 bytenr;
 258         u64 *logical;
 259         int stripe_len;
 260         int i, nr, ret;
 261
 262         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 263                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 264                 cache->bytes_super += stripe_len;
 265                 ret = add_excluded_extent(root, cache->key.objectid,
 266                                           stripe_len);
 267                 if (ret)
 268                         return ret;
 269         }
 270
 271         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 272                 bytenr = btrfs_sb_offset(i);
 273                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 274                                        cache->key.objectid, bytenr,
 275                                        0, &logical, &nr, &stripe_len);
 276                 if (ret)
 277                         return ret;
 278
 279                 while (nr--) {
 280                         u64 start, len;
 281
 282                         if (logical[nr] > cache->key.objectid +
 283                             cache->key.offset)
 284                                 continue;
 285
 286                         if (logical[nr] + stripe_len <= cache->key.objectid)
 287                                 continue;
 288
 289                         start = logical[nr];
 290                         if (start < cache->key.objectid) {
 291                                 start = cache->key.objectid;
 292                                 len = (logical[nr] + stripe_len) - start;
 293                         } else {
 294                                 len = min_t(u64, stripe_len,
 295                                             cache->key.objectid +
 296                                             cache->key.offset - start);
 297                         }
 298
 299                         cache->bytes_super += len;
 300                         ret = add_excluded_extent(root, start, len);
 301                         if (ret) {
 302                                 kfree(logical);
 303                                 return ret;
 304                         }
 305                 }
 306
 307                 kfree(logical);
 308         }
 309         return 0;
 310 }
 311
 312 static struct btrfs_caching_control *
 313 get_caching_control(struct btrfs_block_group_cache *cache)
 314 {
 315         struct btrfs_caching_control *ctl;
 316
 317         spin_lock(&cache->lock);
 318         if (!cache->caching_ctl) {
 319                 spin_unlock(&cache->lock);
 320                 return NULL;
 321         }
 322
 323         ctl = cache->caching_ctl;
 324         atomic_inc(&ctl->count);
 325         spin_unlock(&cache->lock);
 326         return ctl;
 327 }
 328
 329 static void put_caching_control(struct btrfs_caching_control *ctl)
 330 {
 331         if (atomic_dec_and_test(&ctl->count))
 332                 kfree(ctl);
 333 }
 334
 335 /*
 336  * this is only called by cache_block_group, since we could have freed extents
 337  * we need to check the pinned_extents for any extents that can't be used yet
 338  * since their free space will be released as soon as the transaction commits.
 339  */
 340 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 341                               struct btrfs_fs_info *info, u64 start, u64 end)
 342 {
 343         u64 extent_start, extent_end, size, total_added = 0;
 344         int ret;
 345
 346         while (start < end) {
 347                 ret = find_first_extent_bit(info->pinned_extents, start,
 348                                             &extent_start, &extent_end,
 349                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 350                                             NULL);
 351                 if (ret)
 352                         break;
 353
 354                 if (extent_start <= start) {
 355                         start = extent_end + 1;
 356                 } else if (extent_start > start && extent_start < end) {
 357                         size = extent_start - start;
 358                         total_added += size;
 359                         ret = btrfs_add_free_space(block_group, start,
 360                                                    size);
 361                         BUG_ON(ret); /* -ENOMEM or logic error */
 362                         start = extent_end + 1;
 363                 } else {
 364                         break;
 365                 }
 366         }
 367
 368         if (start < end) {
 369                 size = end - start;
 370                 total_added += size;
 371                 ret = btrfs_add_free_space(block_group, start, size);
 372                 BUG_ON(ret); /* -ENOMEM or logic error */
 373         }
 374
 375         return total_added;
 376 }
 377
 378 static noinline void caching_thread(struct btrfs_work *work)
 379 {
 380         struct btrfs_block_group_cache *block_group;
 381         struct btrfs_fs_info *fs_info;
 382         struct btrfs_caching_control *caching_ctl;
 383         struct btrfs_root *extent_root;
 384         struct btrfs_path *path;
 385         struct extent_buffer *leaf;
 386         struct btrfs_key key;
 387         u64 total_found = 0;
 388         u64 last = 0;
 389         u32 nritems;
 390         int ret = -ENOMEM;
 391
 392         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 393         block_group = caching_ctl->block_group;
 394         fs_info = block_group->fs_info;
 395         extent_root = fs_info->extent_root;
 396
 397         path = btrfs_alloc_path();
 398         if (!path)
 399                 goto out;
 400
 401         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 402
 403         /*
 404          * We don't want to deadlock with somebody trying to allocate a new
 405          * extent for the extent root while also trying to search the extent
 406          * root to add free space.  So we skip locking and search the commit
 407          * root, since its read-only
 408          */
 409         path->skip_locking = 1;
 410         path->search_commit_root = 1;
 411         path->reada = 1;
 412
 413         key.objectid = last;
 414         key.offset = 0;
 415         key.type = BTRFS_EXTENT_ITEM_KEY;
 416 again:
 417         mutex_lock(&caching_ctl->mutex);
 418         /* need to make sure the commit_root doesn't disappear */
 419         down_read(&fs_info->commit_root_sem);
 420
 421 next:
 422         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 423         if (ret < 0)
 424                 goto err;
 425
 426         leaf = path->nodes[0];
 427         nritems = btrfs_header_nritems(leaf);
 428
 429         while (1) {
 430                 if (btrfs_fs_closing(fs_info) > 1) {
 431                         last = (u64)-1;
 432                         break;
 433                 }
 434
 435                 if (path->slots[0] < nritems) {
 436                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 437                 } else {
 438                         ret = find_next_key(path, 0, &key);
 439                         if (ret)
 440                                 break;
 441
 442                         if (need_resched() ||
 443                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 444                                 caching_ctl->progress = last;
 445                                 btrfs_release_path(path);
 446                                 up_read(&fs_info->commit_root_sem);
 447                                 mutex_unlock(&caching_ctl->mutex);
 448                                 cond_resched();
 449                                 goto again;
 450                         }
 451
 452                         ret = btrfs_next_leaf(extent_root, path);
 453                         if (ret < 0)
 454                                 goto err;
 455                         if (ret)
 456                                 break;
 457                         leaf = path->nodes[0];
 458                         nritems = btrfs_header_nritems(leaf);
 459                         continue;
 460                 }
 461
 462                 if (key.objectid < last) {
 463                         key.objectid = last;
 464                         key.offset = 0;
 465                         key.type = BTRFS_EXTENT_ITEM_KEY;
 466
 467                         caching_ctl->progress = last;
 468                         btrfs_release_path(path);
 469                         goto next;
 470                 }
 471
 472                 if (key.objectid < block_group->key.objectid) {
 473                         path->slots[0]++;
 474                         continue;
 475                 }
 476
 477                 if (key.objectid >= block_group->key.objectid +
 478                     block_group->key.offset)
 479                         break;
 480
 481                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 482                     key.type == BTRFS_METADATA_ITEM_KEY) {
 483                         total_found += add_new_free_space(block_group,
 484                                                           fs_info, last,
 485                                                           key.objectid);
 486                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 487                                 last = key.objectid +
 488                                         fs_info->tree_root->nodesize;
 489                         else
 490                                 last = key.objectid + key.offset;
 491
 492                         if (total_found > (1024 * 1024 * 2)) {
 493                                 total_found = 0;
 494                                 wake_up(&caching_ctl->wait);
 495                         }
 496                 }
 497                 path->slots[0]++;
 498         }
 499         ret = 0;
 500
 501         total_found += add_new_free_space(block_group, fs_info, last,
 502                                           block_group->key.objectid +
 503                                           block_group->key.offset);
 504         caching_ctl->progress = (u64)-1;
 505
 506         spin_lock(&block_group->lock);
 507         block_group->caching_ctl = NULL;
 508         block_group->cached = BTRFS_CACHE_FINISHED;
 509         spin_unlock(&block_group->lock);
 510
 511 err:
 512         btrfs_free_path(path);
 513         up_read(&fs_info->commit_root_sem);
 514
 515         free_excluded_extents(extent_root, block_group);
 516
 517         mutex_unlock(&caching_ctl->mutex);
 518 out:
 519         if (ret) {
 520                 spin_lock(&block_group->lock);
 521                 block_group->caching_ctl = NULL;
 522                 block_group->cached = BTRFS_CACHE_ERROR;
 523                 spin_unlock(&block_group->lock);
 524         }
 525         wake_up(&caching_ctl->wait);
 526
 527         put_caching_control(caching_ctl);
 528         btrfs_put_block_group(block_group);
 529 }
 530
 531 static int cache_block_group(struct btrfs_block_group_cache *cache,
 532                              int load_cache_only)
 533 {
 534         DEFINE_WAIT(wait);
 535         struct btrfs_fs_info *fs_info = cache->fs_info;
 536         struct btrfs_caching_control *caching_ctl;
 537         int ret = 0;
 538
 539         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 540         if (!caching_ctl)
 541                 return -ENOMEM;
 542
 543         INIT_LIST_HEAD(&caching_ctl->list);
 544         mutex_init(&caching_ctl->mutex);
 545         init_waitqueue_head(&caching_ctl->wait);
 546         caching_ctl->block_group = cache;
 547         caching_ctl->progress = cache->key.objectid;
 548         atomic_set(&caching_ctl->count, 1);
 549         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 550                         caching_thread, NULL, NULL);
 551
 552         spin_lock(&cache->lock);
 553         /*
 554          * This should be a rare occasion, but this could happen I think in the
 555          * case where one thread starts to load the space cache info, and then
 556          * some other thread starts a transaction commit which tries to do an
 557          * allocation while the other thread is still loading the space cache
 558          * info.  The previous loop should have kept us from choosing this block
 559          * group, but if we've moved to the state where we will wait on caching
 560          * block groups we need to first check if we're doing a fast load here,
 561          * so we can wait for it to finish, otherwise we could end up allocating
 562          * from a block group who's cache gets evicted for one reason or
 563          * another.
 564          */
 565         while (cache->cached == BTRFS_CACHE_FAST) {
 566                 struct btrfs_caching_control *ctl;
 567
 568                 ctl = cache->caching_ctl;
 569                 atomic_inc(&ctl->count);
 570                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 571                 spin_unlock(&cache->lock);
 572
 573                 schedule();
 574
 575                 finish_wait(&ctl->wait, &wait);
 576                 put_caching_control(ctl);
 577                 spin_lock(&cache->lock);
 578         }
 579
 580         if (cache->cached != BTRFS_CACHE_NO) {
 581                 spin_unlock(&cache->lock);
 582                 kfree(caching_ctl);
 583                 return 0;
 584         }
 585         WARN_ON(cache->caching_ctl);
 586         cache->caching_ctl = caching_ctl;
 587         cache->cached = BTRFS_CACHE_FAST;
 588         spin_unlock(&cache->lock);
 589
 590         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 591                 mutex_lock(&caching_ctl->mutex);
 592                 ret = load_free_space_cache(fs_info, cache);
 593
 594                 spin_lock(&cache->lock);
 595                 if (ret == 1) {
 596                         cache->caching_ctl = NULL;
 597                         cache->cached = BTRFS_CACHE_FINISHED;
 598                         cache->last_byte_to_unpin = (u64)-1;
 599                         caching_ctl->progress = (u64)-1;
 600                 } else {
 601                         if (load_cache_only) {
 602                                 cache->caching_ctl = NULL;
 603                                 cache->cached = BTRFS_CACHE_NO;
 604                         } else {
 605                                 cache->cached = BTRFS_CACHE_STARTED;
 606                                 cache->has_caching_ctl = 1;
 607                         }
 608                 }
 609                 spin_unlock(&cache->lock);
 610                 mutex_unlock(&caching_ctl->mutex);
 611
 612                 wake_up(&caching_ctl->wait);
 613                 if (ret == 1) {
 614                         put_caching_control(caching_ctl);
 615                         free_excluded_extents(fs_info->extent_root, cache);
 616                         return 0;
 617                 }
 618         } else {
 619                 /*
 620                  * We are not going to do the fast caching, set cached to the
 621                  * appropriate value and wakeup any waiters.
 622                  */
 623                 spin_lock(&cache->lock);
 624                 if (load_cache_only) {
 625                         cache->caching_ctl = NULL;
 626                         cache->cached = BTRFS_CACHE_NO;
 627                 } else {
 628                         cache->cached = BTRFS_CACHE_STARTED;
 629                         cache->has_caching_ctl = 1;
 630                 }
 631                 spin_unlock(&cache->lock);
 632                 wake_up(&caching_ctl->wait);
 633         }
 634
 635         if (load_cache_only) {
 636                 put_caching_control(caching_ctl);
 637                 return 0;
 638         }
 639
 640         down_write(&fs_info->commit_root_sem);
 641         atomic_inc(&caching_ctl->count);
 642         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 643         up_write(&fs_info->commit_root_sem);
 644
 645         btrfs_get_block_group(cache);
 646
 647         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 648
 649         return ret;
 650 }
 651
 652 /*
 653  * return the block group that starts at or after bytenr
 654  */
 655 static struct btrfs_block_group_cache *
 656 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 657 {
 658         struct btrfs_block_group_cache *cache;
 659
 660         cache = block_group_cache_tree_search(info, bytenr, 0);
 661
 662         return cache;
 663 }
 664
 665 /*
 666  * return the block group that contains the given bytenr
 667  */
 668 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 669                                                  struct btrfs_fs_info *info,
 670                                                  u64 bytenr)
 671 {
 672         struct btrfs_block_group_cache *cache;
 673
 674         cache = block_group_cache_tree_search(info, bytenr, 1);
 675
 676         return cache;
 677 }
 678
 679 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 680                                                   u64 flags)
 681 {
 682         struct list_head *head = &info->space_info;
 683         struct btrfs_space_info *found;
 684
 685         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 686
 687         rcu_read_lock();
 688         list_for_each_entry_rcu(found, head, list) {
 689                 if (found->flags & flags) {
 690                         rcu_read_unlock();
 691                         return found;
 692                 }
 693         }
 694         rcu_read_unlock();
 695         return NULL;
 696 }
 697
 698 /*
 699  * after adding space to the filesystem, we need to clear the full flags
 700  * on all the space infos.
 701  */
 702 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 703 {
 704         struct list_head *head = &info->space_info;
 705         struct btrfs_space_info *found;
 706
 707         rcu_read_lock();
 708         list_for_each_entry_rcu(found, head, list)
 709                 found->full = 0;
 710         rcu_read_unlock();
 711 }
 712
 713 /* simple helper to search for an existing data extent at a given offset */
 714 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
 715 {
 716         int ret;
 717         struct btrfs_key key;
 718         struct btrfs_path *path;
 719
 720         path = btrfs_alloc_path();
 721         if (!path)
 722                 return -ENOMEM;
 723
 724         key.objectid = start;
 725         key.offset = len;
 726         key.type = BTRFS_EXTENT_ITEM_KEY;
 727         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 728                                 0, 0);
 729         btrfs_free_path(path);
 730         return ret;
 731 }
 732
 733 /*
 734  * helper function to lookup reference count and flags of a tree block.
 735  *
 736  * the head node for delayed ref is used to store the sum of all the
 737  * reference count modifications queued up in the rbtree. the head
 738  * node may also store the extent flags to set. This way you can check
 739  * to see what the reference count and extent flags would be if all of
 740  * the delayed refs are not processed.
 741  */
 742 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 743                              struct btrfs_root *root, u64 bytenr,
 744                              u64 offset, int metadata, u64 *refs, u64 *flags)
 745 {
 746         struct btrfs_delayed_ref_head *head;
 747         struct btrfs_delayed_ref_root *delayed_refs;
 748         struct btrfs_path *path;
 749         struct btrfs_extent_item *ei;
 750         struct extent_buffer *leaf;
 751         struct btrfs_key key;
 752         u32 item_size;
 753         u64 num_refs;
 754         u64 extent_flags;
 755         int ret;
 756
 757         /*
 758          * If we don't have skinny metadata, don't bother doing anything
 759          * different
 760          */
 761         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 762                 offset = root->nodesize;
 763                 metadata = 0;
 764         }
 765
 766         path = btrfs_alloc_path();
 767         if (!path)
 768                 return -ENOMEM;
 769
 770         if (!trans) {
 771                 path->skip_locking = 1;
 772                 path->search_commit_root = 1;
 773         }
 774
 775 search_again:
 776         key.objectid = bytenr;
 777         key.offset = offset;
 778         if (metadata)
 779                 key.type = BTRFS_METADATA_ITEM_KEY;
 780         else
 781                 key.type = BTRFS_EXTENT_ITEM_KEY;
 782
 783         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 784                                 &key, path, 0, 0);
 785         if (ret < 0)
 786                 goto out_free;
 787
 788         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 789                 if (path->slots[0]) {
 790                         path->slots[0]--;
 791                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 792                                               path->slots[0]);
 793                         if (key.objectid == bytenr &&
 794                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 795                             key.offset == root->nodesize)
 796                                 ret = 0;
 797                 }
 798         }
 799
 800         if (ret == 0) {
 801                 leaf = path->nodes[0];
 802                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 803                 if (item_size >= sizeof(*ei)) {
 804                         ei = btrfs_item_ptr(leaf, path->slots[0],
 805                                             struct btrfs_extent_item);
 806                         num_refs = btrfs_extent_refs(leaf, ei);
 807                         extent_flags = btrfs_extent_flags(leaf, ei);
 808                 } else {
 809 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 810                         struct btrfs_extent_item_v0 *ei0;
 811                         BUG_ON(item_size != sizeof(*ei0));
 812                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 813                                              struct btrfs_extent_item_v0);
 814                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 815                         /* FIXME: this isn't correct for data */
 816                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 817 #else
 818                         BUG();
 819 #endif
 820                 }
 821                 BUG_ON(num_refs == 0);
 822         } else {
 823                 num_refs = 0;
 824                 extent_flags = 0;
 825                 ret = 0;
 826         }
 827
 828         if (!trans)
 829                 goto out;
 830
 831         delayed_refs = &trans->transaction->delayed_refs;
 832         spin_lock(&delayed_refs->lock);
 833         head = btrfs_find_delayed_ref_head(trans, bytenr);
 834         if (head) {
 835                 if (!mutex_trylock(&head->mutex)) {
 836                         atomic_inc(&head->node.refs);
 837                         spin_unlock(&delayed_refs->lock);
 838
 839                         btrfs_release_path(path);
 840
 841                         /*
 842                          * Mutex was contended, block until it's released and try
 843                          * again
 844                          */
 845                         mutex_lock(&head->mutex);
 846                         mutex_unlock(&head->mutex);
 847                         btrfs_put_delayed_ref(&head->node);
 848                         goto search_again;
 849                 }
 850                 spin_lock(&head->lock);
 851                 if (head->extent_op && head->extent_op->update_flags)
 852                         extent_flags |= head->extent_op->flags_to_set;
 853                 else
 854                         BUG_ON(num_refs == 0);
 855
 856                 num_refs += head->node.ref_mod;
 857                 spin_unlock(&head->lock);
 858                 mutex_unlock(&head->mutex);
 859         }
 860         spin_unlock(&delayed_refs->lock);
 861 out:
 862         WARN_ON(num_refs == 0);
 863         if (refs)
 864                 *refs = num_refs;
 865         if (flags)
 866                 *flags = extent_flags;
 867 out_free:
 868         btrfs_free_path(path);
 869         return ret;
 870 }
 871
 872 /*
 873  * Back reference rules.  Back refs have three main goals:
 874  *
 875  * 1) differentiate between all holders of references to an extent so that
 876  *    when a reference is dropped we can make sure it was a valid reference
 877  *    before freeing the extent.
 878  *
 879  * 2) Provide enough information to quickly find the holders of an extent
 880  *    if we notice a given block is corrupted or bad.
 881  *
 882  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 883  *    maintenance.  This is actually the same as #2, but with a slightly
 884  *    different use case.
 885  *
 886  * There are two kinds of back refs. The implicit back refs is optimized
 887  * for pointers in non-shared tree blocks. For a given pointer in a block,
 888  * back refs of this kind provide information about the block's owner tree
 889  * and the pointer's key. These information allow us to find the block by
 890  * b-tree searching. The full back refs is for pointers in tree blocks not
 891  * referenced by their owner trees. The location of tree block is recorded
 892  * in the back refs. Actually the full back refs is generic, and can be
 893  * used in all cases the implicit back refs is used. The major shortcoming
 894  * of the full back refs is its overhead. Every time a tree block gets
 895  * COWed, we have to update back refs entry for all pointers in it.
 896  *
 897  * For a newly allocated tree block, we use implicit back refs for
 898  * pointers in it. This means most tree related operations only involve
 899  * implicit back refs. For a tree block created in old transaction, the
 900  * only way to drop a reference to it is COW it. So we can detect the
 901  * event that tree block loses its owner tree's reference and do the
 902  * back refs conversion.
 903  *
 904  * When a tree block is COW'd through a tree, there are four cases:
 905  *
 906  * The reference count of the block is one and the tree is the block's
 907  * owner tree. Nothing to do in this case.
 908  *
 909  * The reference count of the block is one and the tree is not the
 910  * block's owner tree. In this case, full back refs is used for pointers
 911  * in the block. Remove these full back refs, add implicit back refs for
 912  * every pointers in the new block.
 913  *
 914  * The reference count of the block is greater than one and the tree is
 915  * the block's owner tree. In this case, implicit back refs is used for
 916  * pointers in the block. Add full back refs for every pointers in the
 917  * block, increase lower level extents' reference counts. The original
 918  * implicit back refs are entailed to the new block.
 919  *
 920  * The reference count of the block is greater than one and the tree is
 921  * not the block's owner tree. Add implicit back refs for every pointer in
 922  * the new block, increase lower level extents' reference count.
 923  *
 924  * Back Reference Key composing:
 925  *
 926  * The key objectid corresponds to the first byte in the extent,
 927  * The key type is used to differentiate between types of back refs.
 928  * There are different meanings of the key offset for different types
 929  * of back refs.
 930  *
 931  * File extents can be referenced by:
 932  *
 933  * - multiple snapshots, subvolumes, or different generations in one subvol
 934  * - different files inside a single subvolume
 935  * - different offsets inside a file (bookend extents in file.c)
 936  *
 937  * The extent ref structure for the implicit back refs has fields for:
 938  *
 939  * - Objectid of the subvolume root
 940  * - objectid of the file holding the reference
 941  * - original offset in the file
 942  * - how many bookend extents
 943  *
 944  * The key offset for the implicit back refs is hash of the first
 945  * three fields.
 946  *
 947  * The extent ref structure for the full back refs has field for:
 948  *
 949  * - number of pointers in the tree leaf
 950  *
 951  * The key offset for the implicit back refs is the first byte of
 952  * the tree leaf
 953  *
 954  * When a file extent is allocated, The implicit back refs is used.
 955  * the fields are filled in:
 956  *
 957  *     (root_key.objectid, inode objectid, offset in file, 1)
 958  *
 959  * When a file extent is removed file truncation, we find the
 960  * corresponding implicit back refs and check the following fields:
 961  *
 962  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 963  *
 964  * Btree extents can be referenced by:
 965  *
 966  * - Different subvolumes
 967  *
 968  * Both the implicit back refs and the full back refs for tree blocks
 969  * only consist of key. The key offset for the implicit back refs is
 970  * objectid of block's owner tree. The key offset for the full back refs
 971  * is the first byte of parent block.
 972  *
 973  * When implicit back refs is used, information about the lowest key and
 974  * level of the tree block are required. These information are stored in
 975  * tree block info structure.
 976  */
 977
 978 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 979 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 980                                   struct btrfs_root *root,
 981                                   struct btrfs_path *path,
 982                                   u64 owner, u32 extra_size)
 983 {
 984         struct btrfs_extent_item *item;
 985         struct btrfs_extent_item_v0 *ei0;
 986         struct btrfs_extent_ref_v0 *ref0;
 987         struct btrfs_tree_block_info *bi;
 988         struct extent_buffer *leaf;
 989         struct btrfs_key key;
 990         struct btrfs_key found_key;
 991         u32 new_size = sizeof(*item);
 992         u64 refs;
 993         int ret;
 994
 995         leaf = path->nodes[0];
 996         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 997
 998         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 999         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1000                              struct btrfs_extent_item_v0);
1001         refs = btrfs_extent_refs_v0(leaf, ei0);
1002
1003         if (owner == (u64)-1) {
1004                 while (1) {
1005                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1006                                 ret = btrfs_next_leaf(root, path);
1007                                 if (ret < 0)
1008                                         return ret;
1009                                 BUG_ON(ret > 0); /* Corruption */
1010                                 leaf = path->nodes[0];
1011                         }
1012                         btrfs_item_key_to_cpu(leaf, &found_key,
1013                                               path->slots[0]);
1014                         BUG_ON(key.objectid != found_key.objectid);
1015                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1016                                 path->slots[0]++;
1017                                 continue;
1018                         }
1019                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1020                                               struct btrfs_extent_ref_v0);
1021                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1022                         break;
1023                 }
1024         }
1025         btrfs_release_path(path);
1026
1027         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1028                 new_size += sizeof(*bi);
1029
1030         new_size -= sizeof(*ei0);
1031         ret = btrfs_search_slot(trans, root, &key, path,
1032                                 new_size + extra_size, 1);
1033         if (ret < 0)
1034                 return ret;
1035         BUG_ON(ret); /* Corruption */
1036
1037         btrfs_extend_item(root, path, new_size);
1038
1039         leaf = path->nodes[0];
1040         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1041         btrfs_set_extent_refs(leaf, item, refs);
1042         /* FIXME: get real generation */
1043         btrfs_set_extent_generation(leaf, item, 0);
1044         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1045                 btrfs_set_extent_flags(leaf, item,
1046                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1047                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1048                 bi = (struct btrfs_tree_block_info *)(item + 1);
1049                 /* FIXME: get first key of the block */
1050                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1051                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1052         } else {
1053                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1054         }
1055         btrfs_mark_buffer_dirty(leaf);
1056         return 0;
1057 }
1058 #endif
1059
1060 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1061 {
1062         u32 high_crc = ~(u32)0;
1063         u32 low_crc = ~(u32)0;
1064         __le64 lenum;
1065
1066         lenum = cpu_to_le64(root_objectid);
1067         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1068         lenum = cpu_to_le64(owner);
1069         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1070         lenum = cpu_to_le64(offset);
1071         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1072
1073         return ((u64)high_crc << 31) ^ (u64)low_crc;
1074 }
1075
1076 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1077                                      struct btrfs_extent_data_ref *ref)
1078 {
1079         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1080                                     btrfs_extent_data_ref_objectid(leaf, ref),
1081                                     btrfs_extent_data_ref_offset(leaf, ref));
1082 }
1083
1084 static int match_extent_data_ref(struct extent_buffer *leaf,
1085                                  struct btrfs_extent_data_ref *ref,
1086                                  u64 root_objectid, u64 owner, u64 offset)
1087 {
1088         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1089             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1090             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1091                 return 0;
1092         return 1;
1093 }
1094
1095 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1096                                            struct btrfs_root *root,
1097                                            struct btrfs_path *path,
1098                                            u64 bytenr, u64 parent,
1099                                            u64 root_objectid,
1100                                            u64 owner, u64 offset)
1101 {
1102         struct btrfs_key key;
1103         struct btrfs_extent_data_ref *ref;
1104         struct extent_buffer *leaf;
1105         u32 nritems;
1106         int ret;
1107         int recow;
1108         int err = -ENOENT;
1109
1110         key.objectid = bytenr;
1111         if (parent) {
1112                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1113                 key.offset = parent;
1114         } else {
1115                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1116                 key.offset = hash_extent_data_ref(root_objectid,
1117                                                   owner, offset);
1118         }
1119 again:
1120         recow = 0;
1121         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1122         if (ret < 0) {
1123                 err = ret;
1124                 goto fail;
1125         }
1126
1127         if (parent) {
1128                 if (!ret)
1129                         return 0;
1130 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1131                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1132                 btrfs_release_path(path);
1133                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1134                 if (ret < 0) {
1135                         err = ret;
1136                         goto fail;
1137                 }
1138                 if (!ret)
1139                         return 0;
1140 #endif
1141                 goto fail;
1142         }
1143
1144         leaf = path->nodes[0];
1145         nritems = btrfs_header_nritems(leaf);
1146         while (1) {
1147                 if (path->slots[0] >= nritems) {
1148                         ret = btrfs_next_leaf(root, path);
1149                         if (ret < 0)
1150                                 err = ret;
1151                         if (ret)
1152                                 goto fail;
1153
1154                         leaf = path->nodes[0];
1155                         nritems = btrfs_header_nritems(leaf);
1156                         recow = 1;
1157                 }
1158
1159                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1160                 if (key.objectid != bytenr ||
1161                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1162                         goto fail;
1163
1164                 ref = btrfs_item_ptr(leaf, path->slots[0],
1165                                      struct btrfs_extent_data_ref);
1166
1167                 if (match_extent_data_ref(leaf, ref, root_objectid,
1168                                           owner, offset)) {
1169                         if (recow) {
1170                                 btrfs_release_path(path);
1171                                 goto again;
1172                         }
1173                         err = 0;
1174                         break;
1175                 }
1176                 path->slots[0]++;
1177         }
1178 fail:
1179         return err;
1180 }
1181
1182 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1183                                            struct btrfs_root *root,
1184                                            struct btrfs_path *path,
1185                                            u64 bytenr, u64 parent,
1186                                            u64 root_objectid, u64 owner,
1187                                            u64 offset, int refs_to_add)
1188 {
1189         struct btrfs_key key;
1190         struct extent_buffer *leaf;
1191         u32 size;
1192         u32 num_refs;
1193         int ret;
1194
1195         key.objectid = bytenr;
1196         if (parent) {
1197                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1198                 key.offset = parent;
1199                 size = sizeof(struct btrfs_shared_data_ref);
1200         } else {
1201                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1202                 key.offset = hash_extent_data_ref(root_objectid,
1203                                                   owner, offset);
1204                 size = sizeof(struct btrfs_extent_data_ref);
1205         }
1206
1207         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1208         if (ret && ret != -EEXIST)
1209                 goto fail;
1210
1211         leaf = path->nodes[0];
1212         if (parent) {
1213                 struct btrfs_shared_data_ref *ref;
1214                 ref = btrfs_item_ptr(leaf, path->slots[0],
1215                                      struct btrfs_shared_data_ref);
1216                 if (ret == 0) {
1217                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1218                 } else {
1219                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1220                         num_refs += refs_to_add;
1221                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1222                 }
1223         } else {
1224                 struct btrfs_extent_data_ref *ref;
1225                 while (ret == -EEXIST) {
1226                         ref = btrfs_item_ptr(leaf, path->slots[0],
1227                                              struct btrfs_extent_data_ref);
1228                         if (match_extent_data_ref(leaf, ref, root_objectid,
1229                                                   owner, offset))
1230                                 break;
1231                         btrfs_release_path(path);
1232                         key.offset++;
1233                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1234                                                       size);
1235                         if (ret && ret != -EEXIST)
1236                                 goto fail;
1237
1238                         leaf = path->nodes[0];
1239                 }
1240                 ref = btrfs_item_ptr(leaf, path->slots[0],
1241                                      struct btrfs_extent_data_ref);
1242                 if (ret == 0) {
1243                         btrfs_set_extent_data_ref_root(leaf, ref,
1244                                                        root_objectid);
1245                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1246                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1247                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1248                 } else {
1249                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1250                         num_refs += refs_to_add;
1251                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1252                 }
1253         }
1254         btrfs_mark_buffer_dirty(leaf);
1255         ret = 0;
1256 fail:
1257         btrfs_release_path(path);
1258         return ret;
1259 }
1260
1261 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1262                                            struct btrfs_root *root,
1263                                            struct btrfs_path *path,
1264                                            int refs_to_drop, int *last_ref)
1265 {
1266         struct btrfs_key key;
1267         struct btrfs_extent_data_ref *ref1 = NULL;
1268         struct btrfs_shared_data_ref *ref2 = NULL;
1269         struct extent_buffer *leaf;
1270         u32 num_refs = 0;
1271         int ret = 0;
1272
1273         leaf = path->nodes[0];
1274         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1275
1276         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1277                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1278                                       struct btrfs_extent_data_ref);
1279                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1280         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1281                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1282                                       struct btrfs_shared_data_ref);
1283                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1284 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1285         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1286                 struct btrfs_extent_ref_v0 *ref0;
1287                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1288                                       struct btrfs_extent_ref_v0);
1289                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1290 #endif
1291         } else {
1292                 BUG();
1293         }
1294
1295         BUG_ON(num_refs < refs_to_drop);
1296         num_refs -= refs_to_drop;
1297
1298         if (num_refs == 0) {
1299                 ret = btrfs_del_item(trans, root, path);
1300                 *last_ref = 1;
1301         } else {
1302                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1303                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1304                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1305                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1306 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1307                 else {
1308                         struct btrfs_extent_ref_v0 *ref0;
1309                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1310                                         struct btrfs_extent_ref_v0);
1311                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1312                 }
1313 #endif
1314                 btrfs_mark_buffer_dirty(leaf);
1315         }
1316         return ret;
1317 }
1318
1319 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1320                                           struct btrfs_extent_inline_ref *iref)
1321 {
1322         struct btrfs_key key;
1323         struct extent_buffer *leaf;
1324         struct btrfs_extent_data_ref *ref1;
1325         struct btrfs_shared_data_ref *ref2;
1326         u32 num_refs = 0;
1327
1328         leaf = path->nodes[0];
1329         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1330         if (iref) {
1331                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1332                     BTRFS_EXTENT_DATA_REF_KEY) {
1333                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1334                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1335                 } else {
1336                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1337                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1338                 }
1339         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1340                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1341                                       struct btrfs_extent_data_ref);
1342                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1343         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1344                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1345                                       struct btrfs_shared_data_ref);
1346                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1347 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1348         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1349                 struct btrfs_extent_ref_v0 *ref0;
1350                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1351                                       struct btrfs_extent_ref_v0);
1352                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1353 #endif
1354         } else {
1355                 WARN_ON(1);
1356         }
1357         return num_refs;
1358 }
1359
1360 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1361                                           struct btrfs_root *root,
1362                                           struct btrfs_path *path,
1363                                           u64 bytenr, u64 parent,
1364                                           u64 root_objectid)
1365 {
1366         struct btrfs_key key;
1367         int ret;
1368
1369         key.objectid = bytenr;
1370         if (parent) {
1371                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1372                 key.offset = parent;
1373         } else {
1374                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1375                 key.offset = root_objectid;
1376         }
1377
1378         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1379         if (ret > 0)
1380                 ret = -ENOENT;
1381 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1382         if (ret == -ENOENT && parent) {
1383                 btrfs_release_path(path);
1384                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1385                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1386                 if (ret > 0)
1387                         ret = -ENOENT;
1388         }
1389 #endif
1390         return ret;
1391 }
1392
1393 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1394                                           struct btrfs_root *root,
1395                                           struct btrfs_path *path,
1396                                           u64 bytenr, u64 parent,
1397                                           u64 root_objectid)
1398 {
1399         struct btrfs_key key;
1400         int ret;
1401
1402         key.objectid = bytenr;
1403         if (parent) {
1404                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1405                 key.offset = parent;
1406         } else {
1407                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1408                 key.offset = root_objectid;
1409         }
1410
1411         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1412         btrfs_release_path(path);
1413         return ret;
1414 }
1415
1416 static inline int extent_ref_type(u64 parent, u64 owner)
1417 {
1418         int type;
1419         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1420                 if (parent > 0)
1421                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1422                 else
1423                         type = BTRFS_TREE_BLOCK_REF_KEY;
1424         } else {
1425                 if (parent > 0)
1426                         type = BTRFS_SHARED_DATA_REF_KEY;
1427                 else
1428                         type = BTRFS_EXTENT_DATA_REF_KEY;
1429         }
1430         return type;
1431 }
1432
1433 static int find_next_key(struct btrfs_path *path, int level,
1434                          struct btrfs_key *key)
1435
1436 {
1437         for (; level < BTRFS_MAX_LEVEL; level++) {
1438                 if (!path->nodes[level])
1439                         break;
1440                 if (path->slots[level] + 1 >=
1441                     btrfs_header_nritems(path->nodes[level]))
1442                         continue;
1443                 if (level == 0)
1444                         btrfs_item_key_to_cpu(path->nodes[level], key,
1445                                               path->slots[level] + 1);
1446                 else
1447                         btrfs_node_key_to_cpu(path->nodes[level], key,
1448                                               path->slots[level] + 1);
1449                 return 0;
1450         }
1451         return 1;
1452 }
1453
1454 /*
1455  * look for inline back ref. if back ref is found, *ref_ret is set
1456  * to the address of inline back ref, and 0 is returned.
1457  *
1458  * if back ref isn't found, *ref_ret is set to the address where it
1459  * should be inserted, and -ENOENT is returned.
1460  *
1461  * if insert is true and there are too many inline back refs, the path
1462  * points to the extent item, and -EAGAIN is returned.
1463  *
1464  * NOTE: inline back refs are ordered in the same way that back ref
1465  *       items in the tree are ordered.
1466  */
1467 static noinline_for_stack
1468 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1469                                  struct btrfs_root *root,
1470                                  struct btrfs_path *path,
1471                                  struct btrfs_extent_inline_ref **ref_ret,
1472                                  u64 bytenr, u64 num_bytes,
1473                                  u64 parent, u64 root_objectid,
1474                                  u64 owner, u64 offset, int insert)
1475 {
1476         struct btrfs_key key;
1477         struct extent_buffer *leaf;
1478         struct btrfs_extent_item *ei;
1479         struct btrfs_extent_inline_ref *iref;
1480         u64 flags;
1481         u64 item_size;
1482         unsigned long ptr;
1483         unsigned long end;
1484         int extra_size;
1485         int type;
1486         int want;
1487         int ret;
1488         int err = 0;
1489         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1490                                                  SKINNY_METADATA);
1491
1492         key.objectid = bytenr;
1493         key.type = BTRFS_EXTENT_ITEM_KEY;
1494         key.offset = num_bytes;
1495
1496         want = extent_ref_type(parent, owner);
1497         if (insert) {
1498                 extra_size = btrfs_extent_inline_ref_size(want);
1499                 path->keep_locks = 1;
1500         } else
1501                 extra_size = -1;
1502
1503         /*
1504          * Owner is our parent level, so we can just add one to get the level
1505          * for the block we are interested in.
1506          */
1507         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1508                 key.type = BTRFS_METADATA_ITEM_KEY;
1509                 key.offset = owner;
1510         }
1511
1512 again:
1513         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1514         if (ret < 0) {
1515                 err = ret;
1516                 goto out;
1517         }
1518
1519         /*
1520          * We may be a newly converted file system which still has the old fat
1521          * extent entries for metadata, so try and see if we have one of those.
1522          */
1523         if (ret > 0 && skinny_metadata) {
1524                 skinny_metadata = false;
1525                 if (path->slots[0]) {
1526                         path->slots[0]--;
1527                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1528                                               path->slots[0]);
1529                         if (key.objectid == bytenr &&
1530                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1531                             key.offset == num_bytes)
1532                                 ret = 0;
1533                 }
1534                 if (ret) {
1535                         key.objectid = bytenr;
1536                         key.type = BTRFS_EXTENT_ITEM_KEY;
1537                         key.offset = num_bytes;
1538                         btrfs_release_path(path);
1539                         goto again;
1540                 }
1541         }
1542
1543         if (ret && !insert) {
1544                 err = -ENOENT;
1545                 goto out;
1546         } else if (WARN_ON(ret)) {
1547                 err = -EIO;
1548                 goto out;
1549         }
1550
1551         leaf = path->nodes[0];
1552         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1553 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1554         if (item_size < sizeof(*ei)) {
1555                 if (!insert) {
1556                         err = -ENOENT;
1557                         goto out;
1558                 }
1559                 ret = convert_extent_item_v0(trans, root, path, owner,
1560                                              extra_size);
1561                 if (ret < 0) {
1562                         err = ret;
1563                         goto out;
1564                 }
1565                 leaf = path->nodes[0];
1566                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1567         }
1568 #endif
1569         BUG_ON(item_size < sizeof(*ei));
1570
1571         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1572         flags = btrfs_extent_flags(leaf, ei);
1573
1574         ptr = (unsigned long)(ei + 1);
1575         end = (unsigned long)ei + item_size;
1576
1577         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1578                 ptr += sizeof(struct btrfs_tree_block_info);
1579                 BUG_ON(ptr > end);
1580         }
1581
1582         err = -ENOENT;
1583         while (1) {
1584                 if (ptr >= end) {
1585                         WARN_ON(ptr > end);
1586                         break;
1587                 }
1588                 iref = (struct btrfs_extent_inline_ref *)ptr;
1589                 type = btrfs_extent_inline_ref_type(leaf, iref);
1590                 if (want < type)
1591                         break;
1592                 if (want > type) {
1593                         ptr += btrfs_extent_inline_ref_size(type);
1594                         continue;
1595                 }
1596
1597                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1598                         struct btrfs_extent_data_ref *dref;
1599                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1600                         if (match_extent_data_ref(leaf, dref, root_objectid,
1601                                                   owner, offset)) {
1602                                 err = 0;
1603                                 break;
1604                         }
1605                         if (hash_extent_data_ref_item(leaf, dref) <
1606                             hash_extent_data_ref(root_objectid, owner, offset))
1607                                 break;
1608                 } else {
1609                         u64 ref_offset;
1610                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1611                         if (parent > 0) {
1612                                 if (parent == ref_offset) {
1613                                         err = 0;
1614                                         break;
1615                                 }
1616                                 if (ref_offset < parent)
1617                                         break;
1618                         } else {
1619                                 if (root_objectid == ref_offset) {
1620                                         err = 0;
1621                                         break;
1622                                 }
1623                                 if (ref_offset < root_objectid)
1624                                         break;
1625                         }
1626                 }
1627                 ptr += btrfs_extent_inline_ref_size(type);
1628         }
1629         if (err == -ENOENT && insert) {
1630                 if (item_size + extra_size >=
1631                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1632                         err = -EAGAIN;
1633                         goto out;
1634                 }
1635                 /*
1636                  * To add new inline back ref, we have to make sure
1637                  * there is no corresponding back ref item.
1638                  * For simplicity, we just do not add new inline back
1639                  * ref if there is any kind of item for this block
1640                  */
1641                 if (find_next_key(path, 0, &key) == 0 &&
1642                     key.objectid == bytenr &&
1643                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1644                         err = -EAGAIN;
1645                         goto out;
1646                 }
1647         }
1648         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1649 out:
1650         if (insert) {
1651                 path->keep_locks = 0;
1652                 btrfs_unlock_up_safe(path, 1);
1653         }
1654         return err;
1655 }
1656
1657 /*
1658  * helper to add new inline back ref
1659  */
1660 static noinline_for_stack
1661 void setup_inline_extent_backref(struct btrfs_root *root,
1662                                  struct btrfs_path *path,
1663                                  struct btrfs_extent_inline_ref *iref,
1664                                  u64 parent, u64 root_objectid,
1665                                  u64 owner, u64 offset, int refs_to_add,
1666                                  struct btrfs_delayed_extent_op *extent_op)
1667 {
1668         struct extent_buffer *leaf;
1669         struct btrfs_extent_item *ei;
1670         unsigned long ptr;
1671         unsigned long end;
1672         unsigned long item_offset;
1673         u64 refs;
1674         int size;
1675         int type;
1676
1677         leaf = path->nodes[0];
1678         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1679         item_offset = (unsigned long)iref - (unsigned long)ei;
1680
1681         type = extent_ref_type(parent, owner);
1682         size = btrfs_extent_inline_ref_size(type);
1683
1684         btrfs_extend_item(root, path, size);
1685
1686         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1687         refs = btrfs_extent_refs(leaf, ei);
1688         refs += refs_to_add;
1689         btrfs_set_extent_refs(leaf, ei, refs);
1690         if (extent_op)
1691                 __run_delayed_extent_op(extent_op, leaf, ei);
1692
1693         ptr = (unsigned long)ei + item_offset;
1694         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1695         if (ptr < end - size)
1696                 memmove_extent_buffer(leaf, ptr + size, ptr,
1697                                       end - size - ptr);
1698
1699         iref = (struct btrfs_extent_inline_ref *)ptr;
1700         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1701         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1702                 struct btrfs_extent_data_ref *dref;
1703                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1704                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1705                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1706                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1707                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1708         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1709                 struct btrfs_shared_data_ref *sref;
1710                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1711                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1712                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1713         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1714                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1715         } else {
1716                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1717         }
1718         btrfs_mark_buffer_dirty(leaf);
1719 }
1720
1721 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1722                                  struct btrfs_root *root,
1723                                  struct btrfs_path *path,
1724                                  struct btrfs_extent_inline_ref **ref_ret,
1725                                  u64 bytenr, u64 num_bytes, u64 parent,
1726                                  u64 root_objectid, u64 owner, u64 offset)
1727 {
1728         int ret;
1729
1730         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1731                                            bytenr, num_bytes, parent,
1732                                            root_objectid, owner, offset, 0);
1733         if (ret != -ENOENT)
1734                 return ret;
1735
1736         btrfs_release_path(path);
1737         *ref_ret = NULL;
1738
1739         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1740                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1741                                             root_objectid);
1742         } else {
1743                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1744                                              root_objectid, owner, offset);
1745         }
1746         return ret;
1747 }
1748
1749 /*
1750  * helper to update/remove inline back ref
1751  */
1752 static noinline_for_stack
1753 void update_inline_extent_backref(struct btrfs_root *root,
1754                                   struct btrfs_path *path,
1755                                   struct btrfs_extent_inline_ref *iref,
1756                                   int refs_to_mod,
1757                                   struct btrfs_delayed_extent_op *extent_op,
1758                                   int *last_ref)
1759 {
1760         struct extent_buffer *leaf;
1761         struct btrfs_extent_item *ei;
1762         struct btrfs_extent_data_ref *dref = NULL;
1763         struct btrfs_shared_data_ref *sref = NULL;
1764         unsigned long ptr;
1765         unsigned long end;
1766         u32 item_size;
1767         int size;
1768         int type;
1769         u64 refs;
1770
1771         leaf = path->nodes[0];
1772         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1773         refs = btrfs_extent_refs(leaf, ei);
1774         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1775         refs += refs_to_mod;
1776         btrfs_set_extent_refs(leaf, ei, refs);
1777         if (extent_op)
1778                 __run_delayed_extent_op(extent_op, leaf, ei);
1779
1780         type = btrfs_extent_inline_ref_type(leaf, iref);
1781
1782         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1783                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1784                 refs = btrfs_extent_data_ref_count(leaf, dref);
1785         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1786                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1787                 refs = btrfs_shared_data_ref_count(leaf, sref);
1788         } else {
1789                 refs = 1;
1790                 BUG_ON(refs_to_mod != -1);
1791         }
1792
1793         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1794         refs += refs_to_mod;
1795
1796         if (refs > 0) {
1797                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1798                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1799                 else
1800                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1801         } else {
1802                 *last_ref = 1;
1803                 size =  btrfs_extent_inline_ref_size(type);
1804                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1805                 ptr = (unsigned long)iref;
1806                 end = (unsigned long)ei + item_size;
1807                 if (ptr + size < end)
1808                         memmove_extent_buffer(leaf, ptr, ptr + size,
1809                                               end - ptr - size);
1810                 item_size -= size;
1811                 btrfs_truncate_item(root, path, item_size, 1);
1812         }
1813         btrfs_mark_buffer_dirty(leaf);
1814 }
1815
1816 static noinline_for_stack
1817 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1818                                  struct btrfs_root *root,
1819                                  struct btrfs_path *path,
1820                                  u64 bytenr, u64 num_bytes, u64 parent,
1821                                  u64 root_objectid, u64 owner,
1822                                  u64 offset, int refs_to_add,
1823                                  struct btrfs_delayed_extent_op *extent_op)
1824 {
1825         struct btrfs_extent_inline_ref *iref;
1826         int ret;
1827
1828         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1829                                            bytenr, num_bytes, parent,
1830                                            root_objectid, owner, offset, 1);
1831         if (ret == 0) {
1832                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1833                 update_inline_extent_backref(root, path, iref,
1834                                              refs_to_add, extent_op, NULL);
1835         } else if (ret == -ENOENT) {
1836                 setup_inline_extent_backref(root, path, iref, parent,
1837                                             root_objectid, owner, offset,
1838                                             refs_to_add, extent_op);
1839                 ret = 0;
1840         }
1841         return ret;
1842 }
1843
1844 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1845                                  struct btrfs_root *root,
1846                                  struct btrfs_path *path,
1847                                  u64 bytenr, u64 parent, u64 root_objectid,
1848                                  u64 owner, u64 offset, int refs_to_add)
1849 {
1850         int ret;
1851         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1852                 BUG_ON(refs_to_add != 1);
1853                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1854                                             parent, root_objectid);
1855         } else {
1856                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1857                                              parent, root_objectid,
1858                                              owner, offset, refs_to_add);
1859         }
1860         return ret;
1861 }
1862
1863 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1864                                  struct btrfs_root *root,
1865                                  struct btrfs_path *path,
1866                                  struct btrfs_extent_inline_ref *iref,
1867                                  int refs_to_drop, int is_data, int *last_ref)
1868 {
1869         int ret = 0;
1870
1871         BUG_ON(!is_data && refs_to_drop != 1);
1872         if (iref) {
1873                 update_inline_extent_backref(root, path, iref,
1874                                              -refs_to_drop, NULL, last_ref);
1875         } else if (is_data) {
1876                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1877                                              last_ref);
1878         } else {
1879                 *last_ref = 1;
1880                 ret = btrfs_del_item(trans, root, path);
1881         }
1882         return ret;
1883 }
1884
1885 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1886 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1887                                u64 *discarded_bytes)
1888 {
1889         int j, ret = 0;
1890         u64 bytes_left, end;
1891         u64 aligned_start = ALIGN(start, 1 << 9);
1892
1893         if (WARN_ON(start != aligned_start)) {
1894                 len -= aligned_start - start;
1895                 len = round_down(len, 1 << 9);
1896                 start = aligned_start;
1897         }
1898
1899         *discarded_bytes = 0;
1900
1901         if (!len)
1902                 return 0;
1903
1904         end = start + len;
1905         bytes_left = len;
1906
1907         /* Skip any superblocks on this device. */
1908         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1909                 u64 sb_start = btrfs_sb_offset(j);
1910                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1911                 u64 size = sb_start - start;
1912
1913                 if (!in_range(sb_start, start, bytes_left) &&
1914                     !in_range(sb_end, start, bytes_left) &&
1915                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1916                         continue;
1917
1918                 /*
1919                  * Superblock spans beginning of range.  Adjust start and
1920                  * try again.
1921                  */
1922                 if (sb_start <= start) {
1923                         start += sb_end - start;
1924                         if (start > end) {
1925                                 bytes_left = 0;
1926                                 break;
1927                         }
1928                         bytes_left = end - start;
1929                         continue;
1930                 }
1931
1932                 if (size) {
1933                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
1934                                                    GFP_NOFS, 0);
1935                         if (!ret)
1936                                 *discarded_bytes += size;
1937                         else if (ret != -EOPNOTSUPP)
1938                                 return ret;
1939                 }
1940
1941                 start = sb_end;
1942                 if (start > end) {
1943                         bytes_left = 0;
1944                         break;
1945                 }
1946                 bytes_left = end - start;
1947         }
1948
1949         if (bytes_left) {
1950                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
1951                                            GFP_NOFS, 0);
1952                 if (!ret)
1953                         *discarded_bytes += bytes_left;
1954         }
1955         return ret;
1956 }
1957
1958 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1959                          u64 num_bytes, u64 *actual_bytes)
1960 {
1961         int ret;
1962         u64 discarded_bytes = 0;
1963         struct btrfs_bio *bbio = NULL;
1964
1965
1966         /* Tell the block device(s) that the sectors can be discarded */
1967         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1968                               bytenr, &num_bytes, &bbio, 0);
1969         /* Error condition is -ENOMEM */
1970         if (!ret) {
1971                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1972                 int i;
1973
1974
1975                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1976                         u64 bytes;
1977                         if (!stripe->dev->can_discard)
1978                                 continue;
1979
1980                         ret = btrfs_issue_discard(stripe->dev->bdev,
1981                                                   stripe->physical,
1982                                                   stripe->length,
1983                                                   &bytes);
1984                         if (!ret)
1985                                 discarded_bytes += bytes;
1986                         else if (ret != -EOPNOTSUPP)
1987                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1988
1989                         /*
1990                          * Just in case we get back EOPNOTSUPP for some reason,
1991                          * just ignore the return value so we don't screw up
1992                          * people calling discard_extent.
1993                          */
1994                         ret = 0;
1995                 }
1996                 btrfs_put_bbio(bbio);
1997         }
1998
1999         if (actual_bytes)
2000                 *actual_bytes = discarded_bytes;
2001
2002
2003         if (ret == -EOPNOTSUPP)
2004                 ret = 0;
2005         return ret;
2006 }
2007
2008 /* Can return -ENOMEM */
2009 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2010                          struct btrfs_root *root,
2011                          u64 bytenr, u64 num_bytes, u64 parent,
2012                          u64 root_objectid, u64 owner, u64 offset,
2013                          int no_quota)
2014 {
2015         int ret;
2016         struct btrfs_fs_info *fs_info = root->fs_info;
2017
2018         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2019                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2020
2021         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2022                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2023                                         num_bytes,
2024                                         parent, root_objectid, (int)owner,
2025                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
2026         } else {
2027                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2028                                         num_bytes,
2029                                         parent, root_objectid, owner, offset,
2030                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
2031         }
2032         return ret;
2033 }
2034
2035 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2036                                   struct btrfs_root *root,
2037                                   struct btrfs_delayed_ref_node *node,
2038                                   u64 parent, u64 root_objectid,
2039                                   u64 owner, u64 offset, int refs_to_add,
2040                                   struct btrfs_delayed_extent_op *extent_op)
2041 {
2042         struct btrfs_fs_info *fs_info = root->fs_info;
2043         struct btrfs_path *path;
2044         struct extent_buffer *leaf;
2045         struct btrfs_extent_item *item;
2046         struct btrfs_key key;
2047         u64 bytenr = node->bytenr;
2048         u64 num_bytes = node->num_bytes;
2049         u64 refs;
2050         int ret;
2051         int no_quota = node->no_quota;
2052
2053         path = btrfs_alloc_path();
2054         if (!path)
2055                 return -ENOMEM;
2056
2057         if (!is_fstree(root_objectid) || !root->fs_info->quota_enabled)
2058                 no_quota = 1;
2059
2060         path->reada = 1;
2061         path->leave_spinning = 1;
2062         /* this will setup the path even if it fails to insert the back ref */
2063         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2064                                            bytenr, num_bytes, parent,
2065                                            root_objectid, owner, offset,
2066                                            refs_to_add, extent_op);
2067         if ((ret < 0 && ret != -EAGAIN) || !ret)
2068                 goto out;
2069
2070         /*
2071          * Ok we had -EAGAIN which means we didn't have space to insert and
2072          * inline extent ref, so just update the reference count and add a
2073          * normal backref.
2074          */
2075         leaf = path->nodes[0];
2076         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2077         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2078         refs = btrfs_extent_refs(leaf, item);
2079         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2080         if (extent_op)
2081                 __run_delayed_extent_op(extent_op, leaf, item);
2082
2083         btrfs_mark_buffer_dirty(leaf);
2084         btrfs_release_path(path);
2085
2086         path->reada = 1;
2087         path->leave_spinning = 1;
2088         /* now insert the actual backref */
2089         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2090                                     path, bytenr, parent, root_objectid,
2091                                     owner, offset, refs_to_add);
2092         if (ret)
2093                 btrfs_abort_transaction(trans, root, ret);
2094 out:
2095         btrfs_free_path(path);
2096         return ret;
2097 }
2098
2099 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2100                                 struct btrfs_root *root,
2101                                 struct btrfs_delayed_ref_node *node,
2102                                 struct btrfs_delayed_extent_op *extent_op,
2103                                 int insert_reserved)
2104 {
2105         int ret = 0;
2106         struct btrfs_delayed_data_ref *ref;
2107         struct btrfs_key ins;
2108         u64 parent = 0;
2109         u64 ref_root = 0;
2110         u64 flags = 0;
2111
2112         ins.objectid = node->bytenr;
2113         ins.offset = node->num_bytes;
2114         ins.type = BTRFS_EXTENT_ITEM_KEY;
2115
2116         ref = btrfs_delayed_node_to_data_ref(node);
2117         trace_run_delayed_data_ref(node, ref, node->action);
2118
2119         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2120                 parent = ref->parent;
2121         ref_root = ref->root;
2122
2123         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2124                 if (extent_op)
2125                         flags |= extent_op->flags_to_set;
2126                 ret = alloc_reserved_file_extent(trans, root,
2127                                                  parent, ref_root, flags,
2128                                                  ref->objectid, ref->offset,
2129                                                  &ins, node->ref_mod);
2130         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2131                 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2132                                              ref_root, ref->objectid,
2133                                              ref->offset, node->ref_mod,
2134                                              extent_op);
2135         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2136                 ret = __btrfs_free_extent(trans, root, node, parent,
2137                                           ref_root, ref->objectid,
2138                                           ref->offset, node->ref_mod,
2139                                           extent_op);
2140         } else {
2141                 BUG();
2142         }
2143         return ret;
2144 }
2145
2146 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2147                                     struct extent_buffer *leaf,
2148                                     struct btrfs_extent_item *ei)
2149 {
2150         u64 flags = btrfs_extent_flags(leaf, ei);
2151         if (extent_op->update_flags) {
2152                 flags |= extent_op->flags_to_set;
2153                 btrfs_set_extent_flags(leaf, ei, flags);
2154         }
2155
2156         if (extent_op->update_key) {
2157                 struct btrfs_tree_block_info *bi;
2158                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2159                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2160                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2161         }
2162 }
2163
2164 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2165                                  struct btrfs_root *root,
2166                                  struct btrfs_delayed_ref_node *node,
2167                                  struct btrfs_delayed_extent_op *extent_op)
2168 {
2169         struct btrfs_key key;
2170         struct btrfs_path *path;
2171         struct btrfs_extent_item *ei;
2172         struct extent_buffer *leaf;
2173         u32 item_size;
2174         int ret;
2175         int err = 0;
2176         int metadata = !extent_op->is_data;
2177
2178         if (trans->aborted)
2179                 return 0;
2180
2181         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2182                 metadata = 0;
2183
2184         path = btrfs_alloc_path();
2185         if (!path)
2186                 return -ENOMEM;
2187
2188         key.objectid = node->bytenr;
2189
2190         if (metadata) {
2191                 key.type = BTRFS_METADATA_ITEM_KEY;
2192                 key.offset = extent_op->level;
2193         } else {
2194                 key.type = BTRFS_EXTENT_ITEM_KEY;
2195                 key.offset = node->num_bytes;
2196         }
2197
2198 again:
2199         path->reada = 1;
2200         path->leave_spinning = 1;
2201         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2202                                 path, 0, 1);
2203         if (ret < 0) {
2204                 err = ret;
2205                 goto out;
2206         }
2207         if (ret > 0) {
2208                 if (metadata) {
2209                         if (path->slots[0] > 0) {
2210                                 path->slots[0]--;
2211                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2212                                                       path->slots[0]);
2213                                 if (key.objectid == node->bytenr &&
2214                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2215                                     key.offset == node->num_bytes)
2216                                         ret = 0;
2217                         }
2218                         if (ret > 0) {
2219                                 btrfs_release_path(path);
2220                                 metadata = 0;
2221
2222                                 key.objectid = node->bytenr;
2223                                 key.offset = node->num_bytes;
2224                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2225                                 goto again;
2226                         }
2227                 } else {
2228                         err = -EIO;
2229                         goto out;
2230                 }
2231         }
2232
2233         leaf = path->nodes[0];
2234         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2235 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2236         if (item_size < sizeof(*ei)) {
2237                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2238                                              path, (u64)-1, 0);
2239                 if (ret < 0) {
2240                         err = ret;
2241                         goto out;
2242                 }
2243                 leaf = path->nodes[0];
2244                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2245         }
2246 #endif
2247         BUG_ON(item_size < sizeof(*ei));
2248         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2249         __run_delayed_extent_op(extent_op, leaf, ei);
2250
2251         btrfs_mark_buffer_dirty(leaf);
2252 out:
2253         btrfs_free_path(path);
2254         return err;
2255 }
2256
2257 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2258                                 struct btrfs_root *root,
2259                                 struct btrfs_delayed_ref_node *node,
2260                                 struct btrfs_delayed_extent_op *extent_op,
2261                                 int insert_reserved)
2262 {
2263         int ret = 0;
2264         struct btrfs_delayed_tree_ref *ref;
2265         struct btrfs_key ins;
2266         u64 parent = 0;
2267         u64 ref_root = 0;
2268         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2269                                                  SKINNY_METADATA);
2270
2271         ref = btrfs_delayed_node_to_tree_ref(node);
2272         trace_run_delayed_tree_ref(node, ref, node->action);
2273
2274         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2275                 parent = ref->parent;
2276         ref_root = ref->root;
2277
2278         ins.objectid = node->bytenr;
2279         if (skinny_metadata) {
2280                 ins.offset = ref->level;
2281                 ins.type = BTRFS_METADATA_ITEM_KEY;
2282         } else {
2283                 ins.offset = node->num_bytes;
2284                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2285         }
2286
2287         BUG_ON(node->ref_mod != 1);
2288         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2289                 BUG_ON(!extent_op || !extent_op->update_flags);
2290                 ret = alloc_reserved_tree_block(trans, root,
2291                                                 parent, ref_root,
2292                                                 extent_op->flags_to_set,
2293                                                 &extent_op->key,
2294                                                 ref->level, &ins,
2295                                                 node->no_quota);
2296         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2297                 ret = __btrfs_inc_extent_ref(trans, root, node,
2298                                              parent, ref_root,
2299                                              ref->level, 0, 1,
2300                                              extent_op);
2301         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2302                 ret = __btrfs_free_extent(trans, root, node,
2303                                           parent, ref_root,
2304                                           ref->level, 0, 1, extent_op);
2305         } else {
2306                 BUG();
2307         }
2308         return ret;
2309 }
2310
2311 /* helper function to actually process a single delayed ref entry */
2312 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2313                                struct btrfs_root *root,
2314                                struct btrfs_delayed_ref_node *node,
2315                                struct btrfs_delayed_extent_op *extent_op,
2316                                int insert_reserved)
2317 {
2318         int ret = 0;
2319
2320         if (trans->aborted) {
2321                 if (insert_reserved)
2322                         btrfs_pin_extent(root, node->bytenr,
2323                                          node->num_bytes, 1);
2324                 return 0;
2325         }
2326
2327         if (btrfs_delayed_ref_is_head(node)) {
2328                 struct btrfs_delayed_ref_head *head;
2329                 /*
2330                  * we've hit the end of the chain and we were supposed
2331                  * to insert this extent into the tree.  But, it got
2332                  * deleted before we ever needed to insert it, so all
2333                  * we have to do is clean up the accounting
2334                  */
2335                 BUG_ON(extent_op);
2336                 head = btrfs_delayed_node_to_head(node);
2337                 trace_run_delayed_ref_head(node, head, node->action);
2338
2339                 if (insert_reserved) {
2340                         btrfs_pin_extent(root, node->bytenr,
2341                                          node->num_bytes, 1);
2342                         if (head->is_data) {
2343                                 ret = btrfs_del_csums(trans, root,
2344                                                       node->bytenr,
2345                                                       node->num_bytes);
2346                         }
2347                 }
2348
2349                 /* Also free its reserved qgroup space */
2350                 btrfs_qgroup_free_delayed_ref(root->fs_info,
2351                                               head->qgroup_ref_root,
2352                                               head->qgroup_reserved);
2353                 return ret;
2354         }
2355
2356         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2357             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2358                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2359                                            insert_reserved);
2360         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2361                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2362                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2363                                            insert_reserved);
2364         else
2365                 BUG();
2366         return ret;
2367 }
2368
2369 static inline struct btrfs_delayed_ref_node *
2370 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2371 {
2372         struct btrfs_delayed_ref_node *ref;
2373
2374         if (list_empty(&head->ref_list))
2375                 return NULL;
2376
2377         /*
2378          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2379          * This is to prevent a ref count from going down to zero, which deletes
2380          * the extent item from the extent tree, when there still are references
2381          * to add, which would fail because they would not find the extent item.
2382          */
2383         list_for_each_entry(ref, &head->ref_list, list) {
2384                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2385                         return ref;
2386         }
2387
2388         return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2389                           list);
2390 }
2391
2392 /*
2393  * Returns 0 on success or if called with an already aborted transaction.
2394  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2395  */
2396 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2397                                              struct btrfs_root *root,
2398                                              unsigned long nr)
2399 {
2400         struct btrfs_delayed_ref_root *delayed_refs;
2401         struct btrfs_delayed_ref_node *ref;
2402         struct btrfs_delayed_ref_head *locked_ref = NULL;
2403         struct btrfs_delayed_extent_op *extent_op;
2404         struct btrfs_fs_info *fs_info = root->fs_info;
2405         ktime_t start = ktime_get();
2406         int ret;
2407         unsigned long count = 0;
2408         unsigned long actual_count = 0;
2409         int must_insert_reserved = 0;
2410
2411         delayed_refs = &trans->transaction->delayed_refs;
2412         while (1) {
2413                 if (!locked_ref) {
2414                         if (count >= nr)
2415                                 break;
2416
2417                         spin_lock(&delayed_refs->lock);
2418                         locked_ref = btrfs_select_ref_head(trans);
2419                         if (!locked_ref) {
2420                                 spin_unlock(&delayed_refs->lock);
2421                                 break;
2422                         }
2423
2424                         /* grab the lock that says we are going to process
2425                          * all the refs for this head */
2426                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2427                         spin_unlock(&delayed_refs->lock);
2428                         /*
2429                          * we may have dropped the spin lock to get the head
2430                          * mutex lock, and that might have given someone else
2431                          * time to free the head.  If that's true, it has been
2432                          * removed from our list and we can move on.
2433                          */
2434                         if (ret == -EAGAIN) {
2435                                 locked_ref = NULL;
2436                                 count++;
2437                                 continue;
2438                         }
2439                 }
2440
2441                 spin_lock(&locked_ref->lock);
2442
2443                 /*
2444                  * locked_ref is the head node, so we have to go one
2445                  * node back for any delayed ref updates
2446                  */
2447                 ref = select_delayed_ref(locked_ref);
2448
2449                 if (ref && ref->seq &&
2450                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2451                         spin_unlock(&locked_ref->lock);
2452                         btrfs_delayed_ref_unlock(locked_ref);
2453                         spin_lock(&delayed_refs->lock);
2454                         locked_ref->processing = 0;
2455                         delayed_refs->num_heads_ready++;
2456                         spin_unlock(&delayed_refs->lock);
2457                         locked_ref = NULL;
2458                         cond_resched();
2459                         count++;
2460                         continue;
2461                 }
2462
2463                 /*
2464                  * record the must insert reserved flag before we
2465                  * drop the spin lock.
2466                  */
2467                 must_insert_reserved = locked_ref->must_insert_reserved;
2468                 locked_ref->must_insert_reserved = 0;
2469
2470                 extent_op = locked_ref->extent_op;
2471                 locked_ref->extent_op = NULL;
2472
2473                 if (!ref) {
2474
2475
2476                         /* All delayed refs have been processed, Go ahead
2477                          * and send the head node to run_one_delayed_ref,
2478                          * so that any accounting fixes can happen
2479                          */
2480                         ref = &locked_ref->node;
2481
2482                         if (extent_op && must_insert_reserved) {
2483                                 btrfs_free_delayed_extent_op(extent_op);
2484                                 extent_op = NULL;
2485                         }
2486
2487                         if (extent_op) {
2488                                 spin_unlock(&locked_ref->lock);
2489                                 ret = run_delayed_extent_op(trans, root,
2490                                                             ref, extent_op);
2491                                 btrfs_free_delayed_extent_op(extent_op);
2492
2493                                 if (ret) {
2494                                         /*
2495                                          * Need to reset must_insert_reserved if
2496                                          * there was an error so the abort stuff
2497                                          * can cleanup the reserved space
2498                                          * properly.
2499                                          */
2500                                         if (must_insert_reserved)
2501                                                 locked_ref->must_insert_reserved = 1;
2502                                         locked_ref->processing = 0;
2503                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2504                                         btrfs_delayed_ref_unlock(locked_ref);
2505                                         return ret;
2506                                 }
2507                                 continue;
2508                         }
2509
2510                         /*
2511                          * Need to drop our head ref lock and re-aqcuire the
2512                          * delayed ref lock and then re-check to make sure
2513                          * nobody got added.
2514                          */
2515                         spin_unlock(&locked_ref->lock);
2516                         spin_lock(&delayed_refs->lock);
2517                         spin_lock(&locked_ref->lock);
2518                         if (!list_empty(&locked_ref->ref_list) ||
2519                             locked_ref->extent_op) {
2520                                 spin_unlock(&locked_ref->lock);
2521                                 spin_unlock(&delayed_refs->lock);
2522                                 continue;
2523                         }
2524                         ref->in_tree = 0;
2525                         delayed_refs->num_heads--;
2526                         rb_erase(&locked_ref->href_node,
2527                                  &delayed_refs->href_root);
2528                         spin_unlock(&delayed_refs->lock);
2529                 } else {
2530                         actual_count++;
2531                         ref->in_tree = 0;
2532                         list_del(&ref->list);
2533                 }
2534                 atomic_dec(&delayed_refs->num_entries);
2535
2536                 if (!btrfs_delayed_ref_is_head(ref)) {
2537                         /*
2538                          * when we play the delayed ref, also correct the
2539                          * ref_mod on head
2540                          */
2541                         switch (ref->action) {
2542                         case BTRFS_ADD_DELAYED_REF:
2543                         case BTRFS_ADD_DELAYED_EXTENT:
2544                                 locked_ref->node.ref_mod -= ref->ref_mod;
2545                                 break;
2546                         case BTRFS_DROP_DELAYED_REF:
2547                                 locked_ref->node.ref_mod += ref->ref_mod;
2548                                 break;
2549                         default:
2550                                 WARN_ON(1);
2551                         }
2552                 }
2553                 spin_unlock(&locked_ref->lock);
2554
2555                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2556                                           must_insert_reserved);
2557
2558                 btrfs_free_delayed_extent_op(extent_op);
2559                 if (ret) {
2560                         locked_ref->processing = 0;
2561                         btrfs_delayed_ref_unlock(locked_ref);
2562                         btrfs_put_delayed_ref(ref);
2563                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2564                         return ret;
2565                 }
2566
2567                 /*
2568                  * If this node is a head, that means all the refs in this head
2569                  * have been dealt with, and we will pick the next head to deal
2570                  * with, so we must unlock the head and drop it from the cluster
2571                  * list before we release it.
2572                  */
2573                 if (btrfs_delayed_ref_is_head(ref)) {
2574                         if (locked_ref->is_data &&
2575                             locked_ref->total_ref_mod < 0) {
2576                                 spin_lock(&delayed_refs->lock);
2577                                 delayed_refs->pending_csums -= ref->num_bytes;
2578                                 spin_unlock(&delayed_refs->lock);
2579                         }
2580                         btrfs_delayed_ref_unlock(locked_ref);
2581                         locked_ref = NULL;
2582                 }
2583                 btrfs_put_delayed_ref(ref);
2584                 count++;
2585                 cond_resched();
2586         }
2587
2588         /*
2589          * We don't want to include ref heads since we can have empty ref heads
2590          * and those will drastically skew our runtime down since we just do
2591          * accounting, no actual extent tree updates.
2592          */
2593         if (actual_count > 0) {
2594                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2595                 u64 avg;
2596
2597                 /*
2598                  * We weigh the current average higher than our current runtime
2599                  * to avoid large swings in the average.
2600                  */
2601                 spin_lock(&delayed_refs->lock);
2602                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2603                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2604                 spin_unlock(&delayed_refs->lock);
2605         }
2606         return 0;
2607 }
2608
2609 #ifdef SCRAMBLE_DELAYED_REFS
2610 /*
2611  * Normally delayed refs get processed in ascending bytenr order. This
2612  * correlates in most cases to the order added. To expose dependencies on this
2613  * order, we start to process the tree in the middle instead of the beginning
2614  */
2615 static u64 find_middle(struct rb_root *root)
2616 {
2617         struct rb_node *n = root->rb_node;
2618         struct btrfs_delayed_ref_node *entry;
2619         int alt = 1;
2620         u64 middle;
2621         u64 first = 0, last = 0;
2622
2623         n = rb_first(root);
2624         if (n) {
2625                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2626                 first = entry->bytenr;
2627         }
2628         n = rb_last(root);
2629         if (n) {
2630                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2631                 last = entry->bytenr;
2632         }
2633         n = root->rb_node;
2634
2635         while (n) {
2636                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2637                 WARN_ON(!entry->in_tree);
2638
2639                 middle = entry->bytenr;
2640
2641                 if (alt)
2642                         n = n->rb_left;
2643                 else
2644                         n = n->rb_right;
2645
2646                 alt = 1 - alt;
2647         }
2648         return middle;
2649 }
2650 #endif
2651
2652 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2653 {
2654         u64 num_bytes;
2655
2656         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2657                              sizeof(struct btrfs_extent_inline_ref));
2658         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2659                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2660
2661         /*
2662          * We don't ever fill up leaves all the way so multiply by 2 just to be
2663          * closer to what we're really going to want to ouse.
2664          */
2665         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2666 }
2667
2668 /*
2669  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2670  * would require to store the csums for that many bytes.
2671  */
2672 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2673 {
2674         u64 csum_size;
2675         u64 num_csums_per_leaf;
2676         u64 num_csums;
2677
2678         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
2679         num_csums_per_leaf = div64_u64(csum_size,
2680                         (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2681         num_csums = div64_u64(csum_bytes, root->sectorsize);
2682         num_csums += num_csums_per_leaf - 1;
2683         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2684         return num_csums;
2685 }
2686
2687 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2688                                        struct btrfs_root *root)
2689 {
2690         struct btrfs_block_rsv *global_rsv;
2691         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2692         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2693         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2694         u64 num_bytes, num_dirty_bgs_bytes;
2695         int ret = 0;
2696
2697         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2698         num_heads = heads_to_leaves(root, num_heads);
2699         if (num_heads > 1)
2700                 num_bytes += (num_heads - 1) * root->nodesize;
2701         num_bytes <<= 1;
2702         num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2703         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2704                                                              num_dirty_bgs);
2705         global_rsv = &root->fs_info->global_block_rsv;
2706
2707         /*
2708          * If we can't allocate any more chunks lets make sure we have _lots_ of
2709          * wiggle room since running delayed refs can create more delayed refs.
2710          */
2711         if (global_rsv->space_info->full) {
2712                 num_dirty_bgs_bytes <<= 1;
2713                 num_bytes <<= 1;
2714         }
2715
2716         spin_lock(&global_rsv->lock);
2717         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2718                 ret = 1;
2719         spin_unlock(&global_rsv->lock);
2720         return ret;
2721 }
2722
2723 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2724                                        struct btrfs_root *root)
2725 {
2726         struct btrfs_fs_info *fs_info = root->fs_info;
2727         u64 num_entries =
2728                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2729         u64 avg_runtime;
2730         u64 val;
2731
2732         smp_mb();
2733         avg_runtime = fs_info->avg_delayed_ref_runtime;
2734         val = num_entries * avg_runtime;
2735         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2736                 return 1;
2737         if (val >= NSEC_PER_SEC / 2)
2738                 return 2;
2739
2740         return btrfs_check_space_for_delayed_refs(trans, root);
2741 }
2742
2743 struct async_delayed_refs {
2744         struct btrfs_root *root;
2745         int count;
2746         int error;
2747         int sync;
2748         struct completion wait;
2749         struct btrfs_work work;
2750 };
2751
2752 static void delayed_ref_async_start(struct btrfs_work *work)
2753 {
2754         struct async_delayed_refs *async;
2755         struct btrfs_trans_handle *trans;
2756         int ret;
2757
2758         async = container_of(work, struct async_delayed_refs, work);
2759
2760         trans = btrfs_join_transaction(async->root);
2761         if (IS_ERR(trans)) {
2762                 async->error = PTR_ERR(trans);
2763                 goto done;
2764         }
2765
2766         /*
2767          * trans->sync means that when we call end_transaciton, we won't
2768          * wait on delayed refs
2769          */
2770         trans->sync = true;
2771         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2772         if (ret)
2773                 async->error = ret;
2774
2775         ret = btrfs_end_transaction(trans, async->root);
2776         if (ret && !async->error)
2777                 async->error = ret;
2778 done:
2779         if (async->sync)
2780                 complete(&async->wait);
2781         else
2782                 kfree(async);
2783 }
2784
2785 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2786                                  unsigned long count, int wait)
2787 {
2788         struct async_delayed_refs *async;
2789         int ret;
2790
2791         async = kmalloc(sizeof(*async), GFP_NOFS);
2792         if (!async)
2793                 return -ENOMEM;
2794
2795         async->root = root->fs_info->tree_root;
2796         async->count = count;
2797         async->error = 0;
2798         if (wait)
2799                 async->sync = 1;
2800         else
2801                 async->sync = 0;
2802         init_completion(&async->wait);
2803
2804         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2805                         delayed_ref_async_start, NULL, NULL);
2806
2807         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2808
2809         if (wait) {
2810                 wait_for_completion(&async->wait);
2811                 ret = async->error;
2812                 kfree(async);
2813                 return ret;
2814         }
2815         return 0;
2816 }
2817
2818 /*
2819  * this starts processing the delayed reference count updates and
2820  * extent insertions we have queued up so far.  count can be
2821  * 0, which means to process everything in the tree at the start
2822  * of the run (but not newly added entries), or it can be some target
2823  * number you'd like to process.
2824  *
2825  * Returns 0 on success or if called with an aborted transaction
2826  * Returns <0 on error and aborts the transaction
2827  */
2828 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2829                            struct btrfs_root *root, unsigned long count)
2830 {
2831         struct rb_node *node;
2832         struct btrfs_delayed_ref_root *delayed_refs;
2833         struct btrfs_delayed_ref_head *head;
2834         int ret;
2835         int run_all = count == (unsigned long)-1;
2836         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2837
2838         /* We'll clean this up in btrfs_cleanup_transaction */
2839         if (trans->aborted)
2840                 return 0;
2841
2842         if (root == root->fs_info->extent_root)
2843                 root = root->fs_info->tree_root;
2844
2845         delayed_refs = &trans->transaction->delayed_refs;
2846         if (count == 0)
2847                 count = atomic_read(&delayed_refs->num_entries) * 2;
2848
2849 again:
2850 #ifdef SCRAMBLE_DELAYED_REFS
2851         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2852 #endif
2853         trans->can_flush_pending_bgs = false;
2854         ret = __btrfs_run_delayed_refs(trans, root, count);
2855         if (ret < 0) {
2856                 btrfs_abort_transaction(trans, root, ret);
2857                 return ret;
2858         }
2859
2860         if (run_all) {
2861                 if (!list_empty(&trans->new_bgs))
2862                         btrfs_create_pending_block_groups(trans, root);
2863
2864                 spin_lock(&delayed_refs->lock);
2865                 node = rb_first(&delayed_refs->href_root);
2866                 if (!node) {
2867                         spin_unlock(&delayed_refs->lock);
2868                         goto out;
2869                 }
2870                 count = (unsigned long)-1;
2871
2872                 while (node) {
2873                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2874                                         href_node);
2875                         if (btrfs_delayed_ref_is_head(&head->node)) {
2876                                 struct btrfs_delayed_ref_node *ref;
2877
2878                                 ref = &head->node;
2879                                 atomic_inc(&ref->refs);
2880
2881                                 spin_unlock(&delayed_refs->lock);
2882                                 /*
2883                                  * Mutex was contended, block until it's
2884                                  * released and try again
2885                                  */
2886                                 mutex_lock(&head->mutex);
2887                                 mutex_unlock(&head->mutex);
2888
2889                                 btrfs_put_delayed_ref(ref);
2890                                 cond_resched();
2891                                 goto again;
2892                         } else {
2893                                 WARN_ON(1);
2894                         }
2895                         node = rb_next(node);
2896                 }
2897                 spin_unlock(&delayed_refs->lock);
2898                 cond_resched();
2899                 goto again;
2900         }
2901 out:
2902         assert_qgroups_uptodate(trans);
2903         trans->can_flush_pending_bgs = can_flush_pending_bgs;
2904         return 0;
2905 }
2906
2907 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2908                                 struct btrfs_root *root,
2909                                 u64 bytenr, u64 num_bytes, u64 flags,
2910                                 int level, int is_data)
2911 {
2912         struct btrfs_delayed_extent_op *extent_op;
2913         int ret;
2914
2915         extent_op = btrfs_alloc_delayed_extent_op();
2916         if (!extent_op)
2917                 return -ENOMEM;
2918
2919         extent_op->flags_to_set = flags;
2920         extent_op->update_flags = 1;
2921         extent_op->update_key = 0;
2922         extent_op->is_data = is_data ? 1 : 0;
2923         extent_op->level = level;
2924
2925         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2926                                           num_bytes, extent_op);
2927         if (ret)
2928                 btrfs_free_delayed_extent_op(extent_op);
2929         return ret;
2930 }
2931
2932 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2933                                       struct btrfs_root *root,
2934                                       struct btrfs_path *path,
2935                                       u64 objectid, u64 offset, u64 bytenr)
2936 {
2937         struct btrfs_delayed_ref_head *head;
2938         struct btrfs_delayed_ref_node *ref;
2939         struct btrfs_delayed_data_ref *data_ref;
2940         struct btrfs_delayed_ref_root *delayed_refs;
2941         int ret = 0;
2942
2943         delayed_refs = &trans->transaction->delayed_refs;
2944         spin_lock(&delayed_refs->lock);
2945         head = btrfs_find_delayed_ref_head(trans, bytenr);
2946         if (!head) {
2947                 spin_unlock(&delayed_refs->lock);
2948                 return 0;
2949         }
2950
2951         if (!mutex_trylock(&head->mutex)) {
2952                 atomic_inc(&head->node.refs);
2953                 spin_unlock(&delayed_refs->lock);
2954
2955                 btrfs_release_path(path);
2956
2957                 /*
2958                  * Mutex was contended, block until it's released and let
2959                  * caller try again
2960                  */
2961                 mutex_lock(&head->mutex);
2962                 mutex_unlock(&head->mutex);
2963                 btrfs_put_delayed_ref(&head->node);
2964                 return -EAGAIN;
2965         }
2966         spin_unlock(&delayed_refs->lock);
2967
2968         spin_lock(&head->lock);
2969         list_for_each_entry(ref, &head->ref_list, list) {
2970                 /* If it's a shared ref we know a cross reference exists */
2971                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2972                         ret = 1;
2973                         break;
2974                 }
2975
2976                 data_ref = btrfs_delayed_node_to_data_ref(ref);
2977
2978                 /*
2979                  * If our ref doesn't match the one we're currently looking at
2980                  * then we have a cross reference.
2981                  */
2982                 if (data_ref->root != root->root_key.objectid ||
2983                     data_ref->objectid != objectid ||
2984                     data_ref->offset != offset) {
2985                         ret = 1;
2986                         break;
2987                 }
2988         }
2989         spin_unlock(&head->lock);
2990         mutex_unlock(&head->mutex);
2991         return ret;
2992 }
2993
2994 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2995                                         struct btrfs_root *root,
2996                                         struct btrfs_path *path,
2997                                         u64 objectid, u64 offset, u64 bytenr)
2998 {
2999         struct btrfs_root *extent_root = root->fs_info->extent_root;
3000         struct extent_buffer *leaf;
3001         struct btrfs_extent_data_ref *ref;
3002         struct btrfs_extent_inline_ref *iref;
3003         struct btrfs_extent_item *ei;
3004         struct btrfs_key key;
3005         u32 item_size;
3006         int ret;
3007
3008         key.objectid = bytenr;
3009         key.offset = (u64)-1;
3010         key.type = BTRFS_EXTENT_ITEM_KEY;
3011
3012         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3013         if (ret < 0)
3014                 goto out;
3015         BUG_ON(ret == 0); /* Corruption */
3016
3017         ret = -ENOENT;
3018         if (path->slots[0] == 0)
3019                 goto out;
3020
3021         path->slots[0]--;
3022         leaf = path->nodes[0];
3023         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3024
3025         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3026                 goto out;
3027
3028         ret = 1;
3029         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3030 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3031         if (item_size < sizeof(*ei)) {
3032                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3033                 goto out;
3034         }
3035 #endif
3036         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3037
3038         if (item_size != sizeof(*ei) +
3039             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3040                 goto out;
3041
3042         if (btrfs_extent_generation(leaf, ei) <=
3043             btrfs_root_last_snapshot(&root->root_item))
3044                 goto out;
3045
3046         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3047         if (btrfs_extent_inline_ref_type(leaf, iref) !=
3048             BTRFS_EXTENT_DATA_REF_KEY)
3049                 goto out;
3050
3051         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3052         if (btrfs_extent_refs(leaf, ei) !=
3053             btrfs_extent_data_ref_count(leaf, ref) ||
3054             btrfs_extent_data_ref_root(leaf, ref) !=
3055             root->root_key.objectid ||
3056             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3057             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3058                 goto out;
3059
3060         ret = 0;
3061 out:
3062         return ret;
3063 }
3064
3065 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3066                           struct btrfs_root *root,
3067                           u64 objectid, u64 offset, u64 bytenr)
3068 {
3069         struct btrfs_path *path;
3070         int ret;
3071         int ret2;
3072
3073         path = btrfs_alloc_path();
3074         if (!path)
3075                 return -ENOENT;
3076
3077         do {
3078                 ret = check_committed_ref(trans, root, path, objectid,
3079                                           offset, bytenr);
3080                 if (ret && ret != -ENOENT)
3081                         goto out;
3082
3083                 ret2 = check_delayed_ref(trans, root, path, objectid,
3084                                          offset, bytenr);
3085         } while (ret2 == -EAGAIN);
3086
3087         if (ret2 && ret2 != -ENOENT) {
3088                 ret = ret2;
3089                 goto out;
3090         }
3091
3092         if (ret != -ENOENT || ret2 != -ENOENT)
3093                 ret = 0;
3094 out:
3095         btrfs_free_path(path);
3096         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3097                 WARN_ON(ret > 0);
3098         return ret;
3099 }
3100
3101 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3102                            struct btrfs_root *root,
3103                            struct extent_buffer *buf,
3104                            int full_backref, int inc)
3105 {
3106         u64 bytenr;
3107         u64 num_bytes;
3108         u64 parent;
3109         u64 ref_root;
3110         u32 nritems;
3111         struct btrfs_key key;
3112         struct btrfs_file_extent_item *fi;
3113         int i;
3114         int level;
3115         int ret = 0;
3116         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3117                             u64, u64, u64, u64, u64, u64, int);
3118
3119
3120         if (btrfs_test_is_dummy_root(root))
3121                 return 0;
3122
3123         ref_root = btrfs_header_owner(buf);
3124         nritems = btrfs_header_nritems(buf);
3125         level = btrfs_header_level(buf);
3126
3127         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3128                 return 0;
3129
3130         if (inc)
3131                 process_func = btrfs_inc_extent_ref;
3132         else
3133                 process_func = btrfs_free_extent;
3134
3135         if (full_backref)
3136                 parent = buf->start;
3137         else
3138                 parent = 0;
3139
3140         for (i = 0; i < nritems; i++) {
3141                 if (level == 0) {
3142                         btrfs_item_key_to_cpu(buf, &key, i);
3143                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3144                                 continue;
3145                         fi = btrfs_item_ptr(buf, i,
3146                                             struct btrfs_file_extent_item);
3147                         if (btrfs_file_extent_type(buf, fi) ==
3148                             BTRFS_FILE_EXTENT_INLINE)
3149                                 continue;
3150                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3151                         if (bytenr == 0)
3152                                 continue;
3153
3154                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3155                         key.offset -= btrfs_file_extent_offset(buf, fi);
3156                         ret = process_func(trans, root, bytenr, num_bytes,
3157                                            parent, ref_root, key.objectid,
3158                                            key.offset, 1);
3159                         if (ret)
3160                                 goto fail;
3161                 } else {
3162                         bytenr = btrfs_node_blockptr(buf, i);
3163                         num_bytes = root->nodesize;
3164                         ret = process_func(trans, root, bytenr, num_bytes,
3165                                            parent, ref_root, level - 1, 0,
3166                                            1);
3167                         if (ret)
3168                                 goto fail;
3169                 }
3170         }
3171         return 0;
3172 fail:
3173         return ret;
3174 }
3175
3176 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3177                   struct extent_buffer *buf, int full_backref)
3178 {
3179         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3180 }
3181
3182 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3183                   struct extent_buffer *buf, int full_backref)
3184 {
3185         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3186 }
3187
3188 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3189                                  struct btrfs_root *root,
3190                                  struct btrfs_path *path,
3191                                  struct btrfs_block_group_cache *cache)
3192 {
3193         int ret;
3194         struct btrfs_root *extent_root = root->fs_info->extent_root;
3195         unsigned long bi;
3196         struct extent_buffer *leaf;
3197
3198         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3199         if (ret) {
3200                 if (ret > 0)
3201                         ret = -ENOENT;
3202                 goto fail;
3203         }
3204
3205         leaf = path->nodes[0];
3206         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3207         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3208         btrfs_mark_buffer_dirty(leaf);
3209 fail:
3210         btrfs_release_path(path);
3211         return ret;
3212
3213 }
3214
3215 static struct btrfs_block_group_cache *
3216 next_block_group(struct btrfs_root *root,
3217                  struct btrfs_block_group_cache *cache)
3218 {
3219         struct rb_node *node;
3220
3221         spin_lock(&root->fs_info->block_group_cache_lock);
3222
3223         /* If our block group was removed, we need a full search. */
3224         if (RB_EMPTY_NODE(&cache->cache_node)) {
3225                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3226
3227                 spin_unlock(&root->fs_info->block_group_cache_lock);
3228                 btrfs_put_block_group(cache);
3229                 cache = btrfs_lookup_first_block_group(root->fs_info,
3230                                                        next_bytenr);
3231                 return cache;
3232         }
3233         node = rb_next(&cache->cache_node);
3234         btrfs_put_block_group(cache);
3235         if (node) {
3236                 cache = rb_entry(node, struct btrfs_block_group_cache,
3237                                  cache_node);
3238                 btrfs_get_block_group(cache);
3239         } else
3240                 cache = NULL;
3241         spin_unlock(&root->fs_info->block_group_cache_lock);
3242         return cache;
3243 }
3244
3245 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3246                             struct btrfs_trans_handle *trans,
3247                             struct btrfs_path *path)
3248 {
3249         struct btrfs_root *root = block_group->fs_info->tree_root;
3250         struct inode *inode = NULL;
3251         u64 alloc_hint = 0;
3252         int dcs = BTRFS_DC_ERROR;
3253         u64 num_pages = 0;
3254         int retries = 0;
3255         int ret = 0;
3256
3257         /*
3258          * If this block group is smaller than 100 megs don't bother caching the
3259          * block group.
3260          */
3261         if (block_group->key.offset < (100 * 1024 * 1024)) {
3262                 spin_lock(&block_group->lock);
3263                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3264                 spin_unlock(&block_group->lock);
3265                 return 0;
3266         }
3267
3268         if (trans->aborted)
3269                 return 0;
3270 again:
3271         inode = lookup_free_space_inode(root, block_group, path);
3272         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3273                 ret = PTR_ERR(inode);
3274                 btrfs_release_path(path);
3275                 goto out;
3276         }
3277
3278         if (IS_ERR(inode)) {
3279                 BUG_ON(retries);
3280                 retries++;
3281
3282                 if (block_group->ro)
3283                         goto out_free;
3284
3285                 ret = create_free_space_inode(root, trans, block_group, path);
3286                 if (ret)
3287                         goto out_free;
3288                 goto again;
3289         }
3290
3291         /* We've already setup this transaction, go ahead and exit */
3292         if (block_group->cache_generation == trans->transid &&
3293             i_size_read(inode)) {
3294                 dcs = BTRFS_DC_SETUP;
3295                 goto out_put;
3296         }
3297
3298         /*
3299          * We want to set the generation to 0, that way if anything goes wrong
3300          * from here on out we know not to trust this cache when we load up next
3301          * time.
3302          */
3303         BTRFS_I(inode)->generation = 0;
3304         ret = btrfs_update_inode(trans, root, inode);
3305         if (ret) {
3306                 /*
3307                  * So theoretically we could recover from this, simply set the
3308                  * super cache generation to 0 so we know to invalidate the
3309                  * cache, but then we'd have to keep track of the block groups
3310                  * that fail this way so we know we _have_ to reset this cache
3311                  * before the next commit or risk reading stale cache.  So to
3312                  * limit our exposure to horrible edge cases lets just abort the
3313                  * transaction, this only happens in really bad situations
3314                  * anyway.
3315                  */
3316                 btrfs_abort_transaction(trans, root, ret);
3317                 goto out_put;
3318         }
3319         WARN_ON(ret);
3320
3321         if (i_size_read(inode) > 0) {
3322                 ret = btrfs_check_trunc_cache_free_space(root,
3323                                         &root->fs_info->global_block_rsv);
3324                 if (ret)
3325                         goto out_put;
3326
3327                 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3328                 if (ret)
3329                         goto out_put;
3330         }
3331
3332         spin_lock(&block_group->lock);
3333         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3334             !btrfs_test_opt(root, SPACE_CACHE)) {
3335                 /*
3336                  * don't bother trying to write stuff out _if_
3337                  * a) we're not cached,
3338                  * b) we're with nospace_cache mount option.
3339                  */
3340                 dcs = BTRFS_DC_WRITTEN;
3341                 spin_unlock(&block_group->lock);
3342                 goto out_put;
3343         }
3344         spin_unlock(&block_group->lock);
3345
3346         /*
3347          * Try to preallocate enough space based on how big the block group is.
3348          * Keep in mind this has to include any pinned space which could end up
3349          * taking up quite a bit since it's not folded into the other space
3350          * cache.
3351          */
3352         num_pages = div_u64(block_group->key.offset, 256 * 1024 * 1024);
3353         if (!num_pages)
3354                 num_pages = 1;
3355
3356         num_pages *= 16;
3357         num_pages *= PAGE_CACHE_SIZE;
3358
3359         ret = __btrfs_check_data_free_space(inode, 0, num_pages);
3360         if (ret)
3361                 goto out_put;
3362
3363         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3364                                               num_pages, num_pages,
3365                                               &alloc_hint);
3366         if (!ret)
3367                 dcs = BTRFS_DC_SETUP;
3368         __btrfs_free_reserved_data_space(inode, 0, num_pages);
3369
3370 out_put:
3371         iput(inode);
3372 out_free:
3373         btrfs_release_path(path);
3374 out:
3375         spin_lock(&block_group->lock);
3376         if (!ret && dcs == BTRFS_DC_SETUP)
3377                 block_group->cache_generation = trans->transid;
3378         block_group->disk_cache_state = dcs;
3379         spin_unlock(&block_group->lock);
3380
3381         return ret;
3382 }
3383
3384 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3385                             struct btrfs_root *root)
3386 {
3387         struct btrfs_block_group_cache *cache, *tmp;
3388         struct btrfs_transaction *cur_trans = trans->transaction;
3389         struct btrfs_path *path;
3390
3391         if (list_empty(&cur_trans->dirty_bgs) ||
3392             !btrfs_test_opt(root, SPACE_CACHE))
3393                 return 0;
3394
3395         path = btrfs_alloc_path();
3396         if (!path)
3397                 return -ENOMEM;
3398
3399         /* Could add new block groups, use _safe just in case */
3400         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3401                                  dirty_list) {
3402                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3403                         cache_save_setup(cache, trans, path);
3404         }
3405
3406         btrfs_free_path(path);
3407         return 0;
3408 }
3409
3410 /*
3411  * transaction commit does final block group cache writeback during a
3412  * critical section where nothing is allowed to change the FS.  This is
3413  * required in order for the cache to actually match the block group,
3414  * but can introduce a lot of latency into the commit.
3415  *
3416  * So, btrfs_start_dirty_block_groups is here to kick off block group
3417  * cache IO.  There's a chance we'll have to redo some of it if the
3418  * block group changes again during the commit, but it greatly reduces
3419  * the commit latency by getting rid of the easy block groups while
3420  * we're still allowing others to join the commit.
3421  */
3422 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3423                                    struct btrfs_root *root)
3424 {
3425         struct btrfs_block_group_cache *cache;
3426         struct btrfs_transaction *cur_trans = trans->transaction;
3427         int ret = 0;
3428         int should_put;
3429         struct btrfs_path *path = NULL;
3430         LIST_HEAD(dirty);
3431         struct list_head *io = &cur_trans->io_bgs;
3432         int num_started = 0;
3433         int loops = 0;
3434
3435         spin_lock(&cur_trans->dirty_bgs_lock);
3436         if (list_empty(&cur_trans->dirty_bgs)) {
3437                 spin_unlock(&cur_trans->dirty_bgs_lock);
3438                 return 0;
3439         }
3440         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3441         spin_unlock(&cur_trans->dirty_bgs_lock);
3442
3443 again:
3444         /*
3445          * make sure all the block groups on our dirty list actually
3446          * exist
3447          */
3448         btrfs_create_pending_block_groups(trans, root);
3449
3450         if (!path) {
3451                 path = btrfs_alloc_path();
3452                 if (!path)
3453                         return -ENOMEM;
3454         }
3455
3456         /*
3457          * cache_write_mutex is here only to save us from balance or automatic
3458          * removal of empty block groups deleting this block group while we are
3459          * writing out the cache
3460          */
3461         mutex_lock(&trans->transaction->cache_write_mutex);
3462         while (!list_empty(&dirty)) {
3463                 cache = list_first_entry(&dirty,
3464                                          struct btrfs_block_group_cache,
3465                                          dirty_list);
3466                 /*
3467                  * this can happen if something re-dirties a block
3468                  * group that is already under IO.  Just wait for it to
3469                  * finish and then do it all again
3470                  */
3471                 if (!list_empty(&cache->io_list)) {
3472                         list_del_init(&cache->io_list);
3473                         btrfs_wait_cache_io(root, trans, cache,
3474                                             &cache->io_ctl, path,
3475                                             cache->key.objectid);
3476                         btrfs_put_block_group(cache);
3477                 }
3478
3479
3480                 /*
3481                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3482                  * if it should update the cache_state.  Don't delete
3483                  * until after we wait.
3484                  *
3485                  * Since we're not running in the commit critical section
3486                  * we need the dirty_bgs_lock to protect from update_block_group
3487                  */
3488                 spin_lock(&cur_trans->dirty_bgs_lock);
3489                 list_del_init(&cache->dirty_list);
3490                 spin_unlock(&cur_trans->dirty_bgs_lock);
3491
3492                 should_put = 1;
3493
3494                 cache_save_setup(cache, trans, path);
3495
3496                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3497                         cache->io_ctl.inode = NULL;
3498                         ret = btrfs_write_out_cache(root, trans, cache, path);
3499                         if (ret == 0 && cache->io_ctl.inode) {
3500                                 num_started++;
3501                                 should_put = 0;
3502
3503                                 /*
3504                                  * the cache_write_mutex is protecting
3505                                  * the io_list
3506                                  */
3507                                 list_add_tail(&cache->io_list, io);
3508                         } else {
3509                                 /*
3510                                  * if we failed to write the cache, the
3511                                  * generation will be bad and life goes on
3512                                  */
3513                                 ret = 0;
3514                         }
3515                 }
3516                 if (!ret) {
3517                         ret = write_one_cache_group(trans, root, path, cache);
3518                         /*
3519                          * Our block group might still be attached to the list
3520                          * of new block groups in the transaction handle of some
3521                          * other task (struct btrfs_trans_handle->new_bgs). This
3522                          * means its block group item isn't yet in the extent
3523                          * tree. If this happens ignore the error, as we will
3524                          * try again later in the critical section of the
3525                          * transaction commit.
3526                          */
3527                         if (ret == -ENOENT) {
3528                                 ret = 0;
3529                                 spin_lock(&cur_trans->dirty_bgs_lock);
3530                                 if (list_empty(&cache->dirty_list)) {
3531                                         list_add_tail(&cache->dirty_list,
3532                                                       &cur_trans->dirty_bgs);
3533                                         btrfs_get_block_group(cache);
3534                                 }
3535                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3536                         } else if (ret) {
3537                                 btrfs_abort_transaction(trans, root, ret);
3538                         }
3539                 }
3540
3541                 /* if its not on the io list, we need to put the block group */
3542                 if (should_put)
3543                         btrfs_put_block_group(cache);
3544
3545                 if (ret)
3546                         break;
3547
3548                 /*
3549                  * Avoid blocking other tasks for too long. It might even save
3550                  * us from writing caches for block groups that are going to be
3551                  * removed.
3552                  */
3553                 mutex_unlock(&trans->transaction->cache_write_mutex);
3554                 mutex_lock(&trans->transaction->cache_write_mutex);
3555         }
3556         mutex_unlock(&trans->transaction->cache_write_mutex);
3557
3558         /*
3559          * go through delayed refs for all the stuff we've just kicked off
3560          * and then loop back (just once)
3561          */
3562         ret = btrfs_run_delayed_refs(trans, root, 0);
3563         if (!ret && loops == 0) {
3564                 loops++;
3565                 spin_lock(&cur_trans->dirty_bgs_lock);
3566                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3567                 /*
3568                  * dirty_bgs_lock protects us from concurrent block group
3569                  * deletes too (not just cache_write_mutex).
3570                  */
3571                 if (!list_empty(&dirty)) {
3572                         spin_unlock(&cur_trans->dirty_bgs_lock);
3573                         goto again;
3574                 }
3575                 spin_unlock(&cur_trans->dirty_bgs_lock);
3576         }
3577
3578         btrfs_free_path(path);
3579         return ret;
3580 }
3581
3582 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3583                                    struct btrfs_root *root)
3584 {
3585         struct btrfs_block_group_cache *cache;
3586         struct btrfs_transaction *cur_trans = trans->transaction;
3587         int ret = 0;
3588         int should_put;
3589         struct btrfs_path *path;
3590         struct list_head *io = &cur_trans->io_bgs;
3591         int num_started = 0;
3592
3593         path = btrfs_alloc_path();
3594         if (!path)
3595                 return -ENOMEM;
3596
3597         /*
3598          * We don't need the lock here since we are protected by the transaction
3599          * commit.  We want to do the cache_save_setup first and then run the
3600          * delayed refs to make sure we have the best chance at doing this all
3601          * in one shot.
3602          */
3603         while (!list_empty(&cur_trans->dirty_bgs)) {
3604                 cache = list_first_entry(&cur_trans->dirty_bgs,
3605                                          struct btrfs_block_group_cache,
3606                                          dirty_list);
3607
3608                 /*
3609                  * this can happen if cache_save_setup re-dirties a block
3610                  * group that is already under IO.  Just wait for it to
3611                  * finish and then do it all again
3612                  */
3613                 if (!list_empty(&cache->io_list)) {
3614                         list_del_init(&cache->io_list);
3615                         btrfs_wait_cache_io(root, trans, cache,
3616                                             &cache->io_ctl, path,
3617                                             cache->key.objectid);
3618                         btrfs_put_block_group(cache);
3619                 }
3620
3621                 /*
3622                  * don't remove from the dirty list until after we've waited
3623                  * on any pending IO
3624                  */
3625                 list_del_init(&cache->dirty_list);
3626                 should_put = 1;
3627
3628                 cache_save_setup(cache, trans, path);
3629
3630                 if (!ret)
3631                         ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3632
3633                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3634                         cache->io_ctl.inode = NULL;
3635                         ret = btrfs_write_out_cache(root, trans, cache, path);
3636                         if (ret == 0 && cache->io_ctl.inode) {
3637                                 num_started++;
3638                                 should_put = 0;
3639                                 list_add_tail(&cache->io_list, io);
3640                         } else {
3641                                 /*
3642                                  * if we failed to write the cache, the
3643                                  * generation will be bad and life goes on
3644                                  */
3645                                 ret = 0;
3646                         }
3647                 }
3648                 if (!ret) {
3649                         ret = write_one_cache_group(trans, root, path, cache);
3650                         if (ret)
3651                                 btrfs_abort_transaction(trans, root, ret);
3652                 }
3653
3654                 /* if its not on the io list, we need to put the block group */
3655                 if (should_put)
3656                         btrfs_put_block_group(cache);
3657         }
3658
3659         while (!list_empty(io)) {
3660                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3661                                          io_list);
3662                 list_del_init(&cache->io_list);
3663                 btrfs_wait_cache_io(root, trans, cache,
3664                                     &cache->io_ctl, path, cache->key.objectid);
3665                 btrfs_put_block_group(cache);
3666         }
3667
3668         btrfs_free_path(path);
3669         return ret;
3670 }
3671
3672 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3673 {
3674         struct btrfs_block_group_cache *block_group;
3675         int readonly = 0;
3676
3677         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3678         if (!block_group || block_group->ro)
3679                 readonly = 1;
3680         if (block_group)
3681                 btrfs_put_block_group(block_group);
3682         return readonly;
3683 }
3684
3685 static const char *alloc_name(u64 flags)
3686 {
3687         switch (flags) {
3688         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3689                 return "mixed";
3690         case BTRFS_BLOCK_GROUP_METADATA:
3691                 return "metadata";
3692         case BTRFS_BLOCK_GROUP_DATA:
3693                 return "data";
3694         case BTRFS_BLOCK_GROUP_SYSTEM:
3695                 return "system";
3696         default:
3697                 WARN_ON(1);
3698                 return "invalid-combination";
3699         };
3700 }
3701
3702 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3703                              u64 total_bytes, u64 bytes_used,
3704                              struct btrfs_space_info **space_info)
3705 {
3706         struct btrfs_space_info *found;
3707         int i;
3708         int factor;
3709         int ret;
3710
3711         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3712                      BTRFS_BLOCK_GROUP_RAID10))
3713                 factor = 2;
3714         else
3715                 factor = 1;
3716
3717         found = __find_space_info(info, flags);
3718         if (found) {
3719                 spin_lock(&found->lock);
3720                 found->total_bytes += total_bytes;
3721                 found->disk_total += total_bytes * factor;
3722                 found->bytes_used += bytes_used;
3723                 found->disk_used += bytes_used * factor;
3724                 if (total_bytes > 0)
3725                         found->full = 0;
3726                 spin_unlock(&found->lock);
3727                 *space_info = found;
3728                 return 0;
3729         }
3730         found = kzalloc(sizeof(*found), GFP_NOFS);
3731         if (!found)
3732                 return -ENOMEM;
3733
3734         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3735         if (ret) {
3736                 kfree(found);
3737                 return ret;
3738         }
3739
3740         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3741                 INIT_LIST_HEAD(&found->block_groups[i]);
3742         init_rwsem(&found->groups_sem);
3743         spin_lock_init(&found->lock);
3744         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3745         found->total_bytes = total_bytes;
3746         found->disk_total = total_bytes * factor;
3747         found->bytes_used = bytes_used;
3748         found->disk_used = bytes_used * factor;
3749         found->bytes_pinned = 0;
3750         found->bytes_reserved = 0;
3751         found->bytes_readonly = 0;
3752         found->bytes_may_use = 0;
3753         found->full = 0;
3754         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3755         found->chunk_alloc = 0;
3756         found->flush = 0;
3757         init_waitqueue_head(&found->wait);
3758         INIT_LIST_HEAD(&found->ro_bgs);
3759
3760         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3761                                     info->space_info_kobj, "%s",
3762                                     alloc_name(found->flags));
3763         if (ret) {
3764                 kfree(found);
3765                 return ret;
3766         }
3767
3768         *space_info = found;
3769         list_add_rcu(&found->list, &info->space_info);
3770         if (flags & BTRFS_BLOCK_GROUP_DATA)
3771                 info->data_sinfo = found;
3772
3773         return ret;
3774 }
3775
3776 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3777 {
3778         u64 extra_flags = chunk_to_extended(flags) &
3779                                 BTRFS_EXTENDED_PROFILE_MASK;
3780
3781         write_seqlock(&fs_info->profiles_lock);
3782         if (flags & BTRFS_BLOCK_GROUP_DATA)
3783                 fs_info->avail_data_alloc_bits |= extra_flags;
3784         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3785                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3786         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3787                 fs_info->avail_system_alloc_bits |= extra_flags;
3788         write_sequnlock(&fs_info->profiles_lock);
3789 }
3790
3791 /*
3792  * returns target flags in extended format or 0 if restripe for this
3793  * chunk_type is not in progress
3794  *
3795  * should be called with either volume_mutex or balance_lock held
3796  */
3797 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3798 {
3799         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3800         u64 target = 0;
3801
3802         if (!bctl)
3803                 return 0;
3804
3805         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3806             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3807                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3808         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3809                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3810                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3811         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3812                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3813                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3814         }
3815
3816         return target;
3817 }
3818
3819 /*
3820  * @flags: available profiles in extended format (see ctree.h)
3821  *
3822  * Returns reduced profile in chunk format.  If profile changing is in
3823  * progress (either running or paused) picks the target profile (if it's
3824  * already available), otherwise falls back to plain reducing.
3825  */
3826 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3827 {
3828         u64 num_devices = root->fs_info->fs_devices->rw_devices;
3829         u64 target;
3830         u64 raid_type;
3831         u64 allowed = 0;
3832
3833         /*
3834          * see if restripe for this chunk_type is in progress, if so
3835          * try to reduce to the target profile
3836          */
3837         spin_lock(&root->fs_info->balance_lock);
3838         target = get_restripe_target(root->fs_info, flags);
3839         if (target) {
3840                 /* pick target profile only if it's already available */
3841                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3842                         spin_unlock(&root->fs_info->balance_lock);
3843                         return extended_to_chunk(target);
3844                 }
3845         }
3846         spin_unlock(&root->fs_info->balance_lock);
3847
3848         /* First, mask out the RAID levels which aren't possible */
3849         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
3850                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
3851                         allowed |= btrfs_raid_group[raid_type];
3852         }
3853         allowed &= flags;
3854
3855         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
3856                 allowed = BTRFS_BLOCK_GROUP_RAID6;
3857         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
3858                 allowed = BTRFS_BLOCK_GROUP_RAID5;
3859         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
3860                 allowed = BTRFS_BLOCK_GROUP_RAID10;
3861         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
3862                 allowed = BTRFS_BLOCK_GROUP_RAID1;
3863         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
3864                 allowed = BTRFS_BLOCK_GROUP_RAID0;
3865
3866         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
3867
3868         return extended_to_chunk(flags | allowed);
3869 }
3870
3871 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
3872 {
3873         unsigned seq;
3874         u64 flags;
3875
3876         do {
3877                 flags = orig_flags;
3878                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3879
3880                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3881                         flags |= root->fs_info->avail_data_alloc_bits;
3882                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3883                         flags |= root->fs_info->avail_system_alloc_bits;
3884                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3885                         flags |= root->fs_info->avail_metadata_alloc_bits;
3886         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3887
3888         return btrfs_reduce_alloc_profile(root, flags);
3889 }
3890
3891 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3892 {
3893         u64 flags;
3894         u64 ret;
3895
3896         if (data)
3897                 flags = BTRFS_BLOCK_GROUP_DATA;
3898         else if (root == root->fs_info->chunk_root)
3899                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3900         else
3901                 flags = BTRFS_BLOCK_GROUP_METADATA;
3902
3903         ret = get_alloc_profile(root, flags);
3904         return ret;
3905 }
3906
3907 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
3908 {
3909         struct btrfs_space_info *data_sinfo;
3910         struct btrfs_root *root = BTRFS_I(inode)->root;
3911         struct btrfs_fs_info *fs_info = root->fs_info;
3912         u64 used;
3913         int ret = 0;
3914         int need_commit = 2;
3915         int have_pinned_space;
3916
3917         /* make sure bytes are sectorsize aligned */
3918         bytes = ALIGN(bytes, root->sectorsize);
3919
3920         if (btrfs_is_free_space_inode(inode)) {
3921                 need_commit = 0;
3922                 ASSERT(current->journal_info);
3923         }
3924
3925         data_sinfo = fs_info->data_sinfo;
3926         if (!data_sinfo)
3927                 goto alloc;
3928
3929 again:
3930         /* make sure we have enough space to handle the data first */
3931         spin_lock(&data_sinfo->lock);
3932         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3933                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3934                 data_sinfo->bytes_may_use;
3935
3936         if (used + bytes > data_sinfo->total_bytes) {
3937                 struct btrfs_trans_handle *trans;
3938
3939                 /*
3940                  * if we don't have enough free bytes in this space then we need
3941                  * to alloc a new chunk.
3942                  */
3943                 if (!data_sinfo->full) {
3944                         u64 alloc_target;
3945
3946                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3947                         spin_unlock(&data_sinfo->lock);
3948 alloc:
3949                         alloc_target = btrfs_get_alloc_profile(root, 1);
3950                         /*
3951                          * It is ugly that we don't call nolock join
3952                          * transaction for the free space inode case here.
3953                          * But it is safe because we only do the data space
3954                          * reservation for the free space cache in the
3955                          * transaction context, the common join transaction
3956                          * just increase the counter of the current transaction
3957                          * handler, doesn't try to acquire the trans_lock of
3958                          * the fs.
3959                          */
3960                         trans = btrfs_join_transaction(root);
3961                         if (IS_ERR(trans))
3962                                 return PTR_ERR(trans);
3963
3964                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3965                                              alloc_target,
3966                                              CHUNK_ALLOC_NO_FORCE);
3967                         btrfs_end_transaction(trans, root);
3968                         if (ret < 0) {
3969                                 if (ret != -ENOSPC)
3970                                         return ret;
3971                                 else {
3972                                         have_pinned_space = 1;
3973                                         goto commit_trans;
3974                                 }
3975                         }
3976
3977                         if (!data_sinfo)
3978                                 data_sinfo = fs_info->data_sinfo;
3979
3980                         goto again;
3981                 }
3982
3983                 /*
3984                  * If we don't have enough pinned space to deal with this
3985                  * allocation, and no removed chunk in current transaction,
3986                  * don't bother committing the transaction.
3987                  */
3988                 have_pinned_space = percpu_counter_compare(
3989                         &data_sinfo->total_bytes_pinned,
3990                         used + bytes - data_sinfo->total_bytes);
3991                 spin_unlock(&data_sinfo->lock);
3992
3993                 /* commit the current transaction and try again */
3994 commit_trans:
3995                 if (need_commit &&
3996                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3997                         need_commit--;
3998
3999                         if (need_commit > 0)
4000                                 btrfs_wait_ordered_roots(fs_info, -1);
4001
4002                         trans = btrfs_join_transaction(root);
4003                         if (IS_ERR(trans))
4004                                 return PTR_ERR(trans);
4005                         if (have_pinned_space >= 0 ||
4006                             trans->transaction->have_free_bgs ||
4007                             need_commit > 0) {
4008                                 ret = btrfs_commit_transaction(trans, root);
4009                                 if (ret)
4010                                         return ret;
4011                                 /*
4012                                  * make sure that all running delayed iput are
4013                                  * done
4014                                  */
4015                                 down_write(&root->fs_info->delayed_iput_sem);
4016                                 up_write(&root->fs_info->delayed_iput_sem);
4017                                 goto again;
4018                         } else {
4019                                 btrfs_end_transaction(trans, root);
4020                         }
4021                 }
4022
4023                 trace_btrfs_space_reservation(root->fs_info,
4024                                               "space_info:enospc",
4025                                               data_sinfo->flags, bytes, 1);
4026                 return -ENOSPC;
4027         }
4028         data_sinfo->bytes_may_use += bytes;
4029         trace_btrfs_space_reservation(root->fs_info, "space_info",
4030                                       data_sinfo->flags, bytes, 1);
4031         spin_unlock(&data_sinfo->lock);
4032
4033         return ret;
4034 }
4035
4036 /*
4037  * This will check the space that the inode allocates from to make sure we have
4038  * enough space for bytes.
4039  */
4040 int btrfs_check_data_free_space(struct inode *inode, u64 bytes, u64 write_bytes)
4041 {
4042         struct btrfs_root *root = BTRFS_I(inode)->root;
4043         int ret;
4044
4045         ret = btrfs_alloc_data_chunk_ondemand(inode, bytes);
4046         if (ret < 0)
4047                 return ret;
4048         ret = btrfs_qgroup_reserve(root, write_bytes);
4049         return ret;
4050 }
4051
4052 /*
4053  * New check_data_free_space() with ability for precious data reservation
4054  * Will replace old btrfs_check_data_free_space(), but for patch split,
4055  * add a new function first and then replace it.
4056  */
4057 int __btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4058 {
4059         struct btrfs_root *root = BTRFS_I(inode)->root;
4060         int ret;
4061
4062         /* align the range */
4063         len = round_up(start + len, root->sectorsize) -
4064               round_down(start, root->sectorsize);
4065         start = round_down(start, root->sectorsize);
4066
4067         ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4068         if (ret < 0)
4069                 return ret;
4070
4071         /* Use new btrfs_qgroup_reserve_data to reserve precious data space */
4072         ret = btrfs_qgroup_reserve_data(inode, start, len);
4073         return ret;
4074 }
4075
4076 /*
4077  * Called if we need to clear a data reservation for this inode.
4078  */
4079 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
4080 {
4081         struct btrfs_root *root = BTRFS_I(inode)->root;
4082         struct btrfs_space_info *data_sinfo;
4083
4084         /* make sure bytes are sectorsize aligned */
4085         bytes = ALIGN(bytes, root->sectorsize);
4086
4087         data_sinfo = root->fs_info->data_sinfo;
4088         spin_lock(&data_sinfo->lock);
4089         WARN_ON(data_sinfo->bytes_may_use < bytes);
4090         data_sinfo->bytes_may_use -= bytes;
4091         trace_btrfs_space_reservation(root->fs_info, "space_info",
4092                                       data_sinfo->flags, bytes, 0);
4093         spin_unlock(&data_sinfo->lock);
4094 }
4095
4096 /*
4097  * Called if we need to clear a data reservation for this inode
4098  * Normally in a error case.
4099  *
4100  * This one will handle the per-indoe data rsv map for accurate reserved
4101  * space framework.
4102  */
4103 void __btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4104 {
4105         struct btrfs_root *root = BTRFS_I(inode)->root;
4106         struct btrfs_space_info *data_sinfo;
4107
4108         /* Make sure the range is aligned to sectorsize */
4109         len = round_up(start + len, root->sectorsize) -
4110               round_down(start, root->sectorsize);
4111         start = round_down(start, root->sectorsize);
4112
4113         /*
4114          * Free any reserved qgroup data space first
4115          * As it will alloc memory, we can't do it with data sinfo
4116          * spinlock hold.
4117          */
4118         btrfs_qgroup_free_data(inode, start, len);
4119
4120         data_sinfo = root->fs_info->data_sinfo;
4121         spin_lock(&data_sinfo->lock);
4122         if (WARN_ON(data_sinfo->bytes_may_use < len))
4123                 data_sinfo->bytes_may_use = 0;
4124         else
4125                 data_sinfo->bytes_may_use -= len;
4126         trace_btrfs_space_reservation(root->fs_info, "space_info",
4127                                       data_sinfo->flags, len, 0);
4128         spin_unlock(&data_sinfo->lock);
4129 }
4130
4131 static void force_metadata_allocation(struct btrfs_fs_info *info)
4132 {
4133         struct list_head *head = &info->space_info;
4134         struct btrfs_space_info *found;
4135
4136         rcu_read_lock();
4137         list_for_each_entry_rcu(found, head, list) {
4138                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4139                         found->force_alloc = CHUNK_ALLOC_FORCE;
4140         }
4141         rcu_read_unlock();
4142 }
4143
4144 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4145 {
4146         return (global->size << 1);
4147 }
4148
4149 static int should_alloc_chunk(struct btrfs_root *root,
4150                               struct btrfs_space_info *sinfo, int force)
4151 {
4152         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4153         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4154         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4155         u64 thresh;
4156
4157         if (force == CHUNK_ALLOC_FORCE)
4158                 return 1;
4159
4160         /*
4161          * We need to take into account the global rsv because for all intents
4162          * and purposes it's used space.  Don't worry about locking the
4163          * global_rsv, it doesn't change except when the transaction commits.
4164          */
4165         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4166                 num_allocated += calc_global_rsv_need_space(global_rsv);
4167
4168         /*
4169          * in limited mode, we want to have some free space up to
4170          * about 1% of the FS size.
4171          */
4172         if (force == CHUNK_ALLOC_LIMITED) {
4173                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4174                 thresh = max_t(u64, 64 * 1024 * 1024,
4175                                div_factor_fine(thresh, 1));
4176
4177                 if (num_bytes - num_allocated < thresh)
4178                         return 1;
4179         }
4180
4181         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
4182                 return 0;
4183         return 1;
4184 }
4185
4186 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4187 {
4188         u64 num_dev;
4189
4190         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4191                     BTRFS_BLOCK_GROUP_RAID0 |
4192                     BTRFS_BLOCK_GROUP_RAID5 |
4193                     BTRFS_BLOCK_GROUP_RAID6))
4194                 num_dev = root->fs_info->fs_devices->rw_devices;
4195         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4196                 num_dev = 2;
4197         else
4198                 num_dev = 1;    /* DUP or single */
4199
4200         return num_dev;
4201 }
4202
4203 /*
4204  * If @is_allocation is true, reserve space in the system space info necessary
4205  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4206  * removing a chunk.
4207  */
4208 void check_system_chunk(struct btrfs_trans_handle *trans,
4209                         struct btrfs_root *root,
4210                         u64 type)
4211 {
4212         struct btrfs_space_info *info;
4213         u64 left;
4214         u64 thresh;
4215         int ret = 0;
4216         u64 num_devs;
4217
4218         /*
4219          * Needed because we can end up allocating a system chunk and for an
4220          * atomic and race free space reservation in the chunk block reserve.
4221          */
4222         ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4223
4224         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4225         spin_lock(&info->lock);
4226         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4227                 info->bytes_reserved - info->bytes_readonly -
4228                 info->bytes_may_use;
4229         spin_unlock(&info->lock);
4230
4231         num_devs = get_profile_num_devs(root, type);
4232
4233         /* num_devs device items to update and 1 chunk item to add or remove */
4234         thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4235                 btrfs_calc_trans_metadata_size(root, 1);
4236
4237         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
4238                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4239                         left, thresh, type);
4240                 dump_space_info(info, 0, 0);
4241         }
4242
4243         if (left < thresh) {
4244                 u64 flags;
4245
4246                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4247                 /*
4248                  * Ignore failure to create system chunk. We might end up not
4249                  * needing it, as we might not need to COW all nodes/leafs from
4250                  * the paths we visit in the chunk tree (they were already COWed
4251                  * or created in the current transaction for example).
4252                  */
4253                 ret = btrfs_alloc_chunk(trans, root, flags);
4254         }
4255
4256         if (!ret) {
4257                 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4258                                           &root->fs_info->chunk_block_rsv,
4259                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4260                 if (!ret)
4261                         trans->chunk_bytes_reserved += thresh;
4262         }
4263 }
4264
4265 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4266                           struct btrfs_root *extent_root, u64 flags, int force)
4267 {
4268         struct btrfs_space_info *space_info;
4269         struct btrfs_fs_info *fs_info = extent_root->fs_info;
4270         int wait_for_alloc = 0;
4271         int ret = 0;
4272
4273         /* Don't re-enter if we're already allocating a chunk */
4274         if (trans->allocating_chunk)
4275                 return -ENOSPC;
4276
4277         space_info = __find_space_info(extent_root->fs_info, flags);
4278         if (!space_info) {
4279                 ret = update_space_info(extent_root->fs_info, flags,
4280                                         0, 0, &space_info);
4281                 BUG_ON(ret); /* -ENOMEM */
4282         }
4283         BUG_ON(!space_info); /* Logic error */
4284
4285 again:
4286         spin_lock(&space_info->lock);
4287         if (force < space_info->force_alloc)
4288                 force = space_info->force_alloc;
4289         if (space_info->full) {
4290                 if (should_alloc_chunk(extent_root, space_info, force))
4291                         ret = -ENOSPC;
4292                 else
4293                         ret = 0;
4294                 spin_unlock(&space_info->lock);
4295                 return ret;
4296         }
4297
4298         if (!should_alloc_chunk(extent_root, space_info, force)) {
4299                 spin_unlock(&space_info->lock);
4300                 return 0;
4301         } else if (space_info->chunk_alloc) {
4302                 wait_for_alloc = 1;
4303         } else {
4304                 space_info->chunk_alloc = 1;
4305         }
4306
4307         spin_unlock(&space_info->lock);
4308
4309         mutex_lock(&fs_info->chunk_mutex);
4310
4311         /*
4312          * The chunk_mutex is held throughout the entirety of a chunk
4313          * allocation, so once we've acquired the chunk_mutex we know that the
4314          * other guy is done and we need to recheck and see if we should
4315          * allocate.
4316          */
4317         if (wait_for_alloc) {
4318                 mutex_unlock(&fs_info->chunk_mutex);
4319                 wait_for_alloc = 0;
4320                 goto again;
4321         }
4322
4323         trans->allocating_chunk = true;
4324
4325         /*
4326          * If we have mixed data/metadata chunks we want to make sure we keep
4327          * allocating mixed chunks instead of individual chunks.
4328          */
4329         if (btrfs_mixed_space_info(space_info))
4330                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4331
4332         /*
4333          * if we're doing a data chunk, go ahead and make sure that
4334          * we keep a reasonable number of metadata chunks allocated in the
4335          * FS as well.
4336          */
4337         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4338                 fs_info->data_chunk_allocations++;
4339                 if (!(fs_info->data_chunk_allocations %
4340                       fs_info->metadata_ratio))
4341                         force_metadata_allocation(fs_info);
4342         }
4343
4344         /*
4345          * Check if we have enough space in SYSTEM chunk because we may need
4346          * to update devices.
4347          */
4348         check_system_chunk(trans, extent_root, flags);
4349
4350         ret = btrfs_alloc_chunk(trans, extent_root, flags);
4351         trans->allocating_chunk = false;
4352
4353         spin_lock(&space_info->lock);
4354         if (ret < 0 && ret != -ENOSPC)
4355                 goto out;
4356         if (ret)
4357                 space_info->full = 1;
4358         else
4359                 ret = 1;
4360
4361         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4362 out:
4363         space_info->chunk_alloc = 0;
4364         spin_unlock(&space_info->lock);
4365         mutex_unlock(&fs_info->chunk_mutex);
4366         /*
4367          * When we allocate a new chunk we reserve space in the chunk block
4368          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4369          * add new nodes/leafs to it if we end up needing to do it when
4370          * inserting the chunk item and updating device items as part of the
4371          * second phase of chunk allocation, performed by
4372          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4373          * large number of new block groups to create in our transaction
4374          * handle's new_bgs list to avoid exhausting the chunk block reserve
4375          * in extreme cases - like having a single transaction create many new
4376          * block groups when starting to write out the free space caches of all
4377          * the block groups that were made dirty during the lifetime of the
4378          * transaction.
4379          */
4380         if (trans->can_flush_pending_bgs &&
4381             trans->chunk_bytes_reserved >= (2 * 1024 * 1024ull)) {
4382                 btrfs_create_pending_block_groups(trans, trans->root);
4383                 btrfs_trans_release_chunk_metadata(trans);
4384         }
4385         return ret;
4386 }
4387
4388 static int can_overcommit(struct btrfs_root *root,
4389                           struct btrfs_space_info *space_info, u64 bytes,
4390                           enum btrfs_reserve_flush_enum flush)
4391 {
4392         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4393         u64 profile = btrfs_get_alloc_profile(root, 0);
4394         u64 space_size;
4395         u64 avail;
4396         u64 used;
4397
4398         used = space_info->bytes_used + space_info->bytes_reserved +
4399                 space_info->bytes_pinned + space_info->bytes_readonly;
4400
4401         /*
4402          * We only want to allow over committing if we have lots of actual space
4403          * free, but if we don't have enough space to handle the global reserve
4404          * space then we could end up having a real enospc problem when trying
4405          * to allocate a chunk or some other such important allocation.
4406          */
4407         spin_lock(&global_rsv->lock);
4408         space_size = calc_global_rsv_need_space(global_rsv);
4409         spin_unlock(&global_rsv->lock);
4410         if (used + space_size >= space_info->total_bytes)
4411                 return 0;
4412
4413         used += space_info->bytes_may_use;
4414
4415         spin_lock(&root->fs_info->free_chunk_lock);
4416         avail = root->fs_info->free_chunk_space;
4417         spin_unlock(&root->fs_info->free_chunk_lock);
4418
4419         /*
4420          * If we have dup, raid1 or raid10 then only half of the free
4421          * space is actually useable.  For raid56, the space info used
4422          * doesn't include the parity drive, so we don't have to
4423          * change the math
4424          */
4425         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4426                        BTRFS_BLOCK_GROUP_RAID1 |
4427                        BTRFS_BLOCK_GROUP_RAID10))
4428                 avail >>= 1;
4429
4430         /*
4431          * If we aren't flushing all things, let us overcommit up to
4432          * 1/2th of the space. If we can flush, don't let us overcommit
4433          * too much, let it overcommit up to 1/8 of the space.
4434          */
4435         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4436                 avail >>= 3;
4437         else
4438                 avail >>= 1;
4439
4440         if (used + bytes < space_info->total_bytes + avail)
4441                 return 1;
4442         return 0;
4443 }
4444
4445 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4446                                          unsigned long nr_pages, int nr_items)
4447 {
4448         struct super_block *sb = root->fs_info->sb;
4449
4450         if (down_read_trylock(&sb->s_umount)) {
4451                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4452                 up_read(&sb->s_umount);
4453         } else {
4454                 /*
4455                  * We needn't worry the filesystem going from r/w to r/o though
4456                  * we don't acquire ->s_umount mutex, because the filesystem
4457                  * should guarantee the delalloc inodes list be empty after
4458                  * the filesystem is readonly(all dirty pages are written to
4459                  * the disk).
4460                  */
4461                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4462                 if (!current->journal_info)
4463                         btrfs_wait_ordered_roots(root->fs_info, nr_items);
4464         }
4465 }
4466
4467 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4468 {
4469         u64 bytes;
4470         int nr;
4471
4472         bytes = btrfs_calc_trans_metadata_size(root, 1);
4473         nr = (int)div64_u64(to_reclaim, bytes);
4474         if (!nr)
4475                 nr = 1;
4476         return nr;
4477 }
4478
4479 #define EXTENT_SIZE_PER_ITEM    (256 * 1024)
4480
4481 /*
4482  * shrink metadata reservation for delalloc
4483  */
4484 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4485                             bool wait_ordered)
4486 {
4487         struct btrfs_block_rsv *block_rsv;
4488         struct btrfs_space_info *space_info;
4489         struct btrfs_trans_handle *trans;
4490         u64 delalloc_bytes;
4491         u64 max_reclaim;
4492         long time_left;
4493         unsigned long nr_pages;
4494         int loops;
4495         int items;
4496         enum btrfs_reserve_flush_enum flush;
4497
4498         /* Calc the number of the pages we need flush for space reservation */
4499         items = calc_reclaim_items_nr(root, to_reclaim);
4500         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4501
4502         trans = (struct btrfs_trans_handle *)current->journal_info;
4503         block_rsv = &root->fs_info->delalloc_block_rsv;
4504         space_info = block_rsv->space_info;
4505
4506         delalloc_bytes = percpu_counter_sum_positive(
4507                                                 &root->fs_info->delalloc_bytes);
4508         if (delalloc_bytes == 0) {
4509                 if (trans)
4510                         return;
4511                 if (wait_ordered)
4512                         btrfs_wait_ordered_roots(root->fs_info, items);
4513                 return;
4514         }
4515
4516         loops = 0;
4517         while (delalloc_bytes && loops < 3) {
4518                 max_reclaim = min(delalloc_bytes, to_reclaim);
4519                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4520                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4521                 /*
4522                  * We need to wait for the async pages to actually start before
4523                  * we do anything.
4524                  */
4525                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4526                 if (!max_reclaim)
4527                         goto skip_async;
4528
4529                 if (max_reclaim <= nr_pages)
4530                         max_reclaim = 0;
4531                 else
4532                         max_reclaim -= nr_pages;
4533
4534                 wait_event(root->fs_info->async_submit_wait,
4535                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4536                            (int)max_reclaim);
4537 skip_async:
4538                 if (!trans)
4539                         flush = BTRFS_RESERVE_FLUSH_ALL;
4540                 else
4541                         flush = BTRFS_RESERVE_NO_FLUSH;
4542                 spin_lock(&space_info->lock);
4543                 if (can_overcommit(root, space_info, orig, flush)) {
4544                         spin_unlock(&space_info->lock);
4545                         break;
4546                 }
4547                 spin_unlock(&space_info->lock);
4548
4549                 loops++;
4550                 if (wait_ordered && !trans) {
4551                         btrfs_wait_ordered_roots(root->fs_info, items);
4552                 } else {
4553                         time_left = schedule_timeout_killable(1);
4554                         if (time_left)
4555                                 break;
4556                 }
4557                 delalloc_bytes = percpu_counter_sum_positive(
4558                                                 &root->fs_info->delalloc_bytes);
4559         }
4560 }
4561
4562 /**
4563  * maybe_commit_transaction - possibly commit the transaction if its ok to
4564  * @root - the root we're allocating for
4565  * @bytes - the number of bytes we want to reserve
4566  * @force - force the commit
4567  *
4568  * This will check to make sure that committing the transaction will actually
4569  * get us somewhere and then commit the transaction if it does.  Otherwise it
4570  * will return -ENOSPC.
4571  */
4572 static int may_commit_transaction(struct btrfs_root *root,
4573                                   struct btrfs_space_info *space_info,
4574                                   u64 bytes, int force)
4575 {
4576         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4577         struct btrfs_trans_handle *trans;
4578
4579         trans = (struct btrfs_trans_handle *)current->journal_info;
4580         if (trans)
4581                 return -EAGAIN;
4582
4583         if (force)
4584                 goto commit;
4585
4586         /* See if there is enough pinned space to make this reservation */
4587         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4588                                    bytes) >= 0)
4589                 goto commit;
4590
4591         /*
4592          * See if there is some space in the delayed insertion reservation for
4593          * this reservation.
4594          */
4595         if (space_info != delayed_rsv->space_info)
4596                 return -ENOSPC;
4597
4598         spin_lock(&delayed_rsv->lock);
4599         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4600                                    bytes - delayed_rsv->size) >= 0) {
4601                 spin_unlock(&delayed_rsv->lock);
4602                 return -ENOSPC;
4603         }
4604         spin_unlock(&delayed_rsv->lock);
4605
4606 commit:
4607         trans = btrfs_join_transaction(root);
4608         if (IS_ERR(trans))
4609                 return -ENOSPC;
4610
4611         return btrfs_commit_transaction(trans, root);
4612 }
4613
4614 enum flush_state {
4615         FLUSH_DELAYED_ITEMS_NR  =       1,
4616         FLUSH_DELAYED_ITEMS     =       2,
4617         FLUSH_DELALLOC          =       3,
4618         FLUSH_DELALLOC_WAIT     =       4,
4619         ALLOC_CHUNK             =       5,
4620         COMMIT_TRANS            =       6,
4621 };
4622
4623 static int flush_space(struct btrfs_root *root,
4624                        struct btrfs_space_info *space_info, u64 num_bytes,
4625                        u64 orig_bytes, int state)
4626 {
4627         struct btrfs_trans_handle *trans;
4628         int nr;
4629         int ret = 0;
4630
4631         switch (state) {
4632         case FLUSH_DELAYED_ITEMS_NR:
4633         case FLUSH_DELAYED_ITEMS:
4634                 if (state == FLUSH_DELAYED_ITEMS_NR)
4635                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4636                 else
4637                         nr = -1;
4638
4639                 trans = btrfs_join_transaction(root);
4640                 if (IS_ERR(trans)) {
4641                         ret = PTR_ERR(trans);
4642                         break;
4643                 }
4644                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4645                 btrfs_end_transaction(trans, root);
4646                 break;
4647         case FLUSH_DELALLOC:
4648         case FLUSH_DELALLOC_WAIT:
4649                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4650                                 state == FLUSH_DELALLOC_WAIT);
4651                 break;
4652         case ALLOC_CHUNK:
4653                 trans = btrfs_join_transaction(root);
4654                 if (IS_ERR(trans)) {
4655                         ret = PTR_ERR(trans);
4656                         break;
4657                 }
4658                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4659                                      btrfs_get_alloc_profile(root, 0),
4660                                      CHUNK_ALLOC_NO_FORCE);
4661                 btrfs_end_transaction(trans, root);
4662                 if (ret == -ENOSPC)
4663                         ret = 0;
4664                 break;
4665         case COMMIT_TRANS:
4666                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4667                 break;
4668         default:
4669                 ret = -ENOSPC;
4670                 break;
4671         }
4672
4673         return ret;
4674 }
4675
4676 static inline u64
4677 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4678                                  struct btrfs_space_info *space_info)
4679 {
4680         u64 used;
4681         u64 expected;
4682         u64 to_reclaim;
4683
4684         to_reclaim = min_t(u64, num_online_cpus() * 1024 * 1024,
4685                                 16 * 1024 * 1024);
4686         spin_lock(&space_info->lock);
4687         if (can_overcommit(root, space_info, to_reclaim,
4688                            BTRFS_RESERVE_FLUSH_ALL)) {
4689                 to_reclaim = 0;
4690                 goto out;
4691         }
4692
4693         used = space_info->bytes_used + space_info->bytes_reserved +
4694                space_info->bytes_pinned + space_info->bytes_readonly +
4695                space_info->bytes_may_use;
4696         if (can_overcommit(root, space_info, 1024 * 1024,
4697                            BTRFS_RESERVE_FLUSH_ALL))
4698                 expected = div_factor_fine(space_info->total_bytes, 95);
4699         else
4700                 expected = div_factor_fine(space_info->total_bytes, 90);
4701
4702         if (used > expected)
4703                 to_reclaim = used - expected;
4704         else
4705                 to_reclaim = 0;
4706         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4707                                      space_info->bytes_reserved);
4708 out:
4709         spin_unlock(&space_info->lock);
4710
4711         return to_reclaim;
4712 }
4713
4714 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4715                                         struct btrfs_fs_info *fs_info, u64 used)
4716 {
4717         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4718
4719         /* If we're just plain full then async reclaim just slows us down. */
4720         if (space_info->bytes_used >= thresh)
4721                 return 0;
4722
4723         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4724                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4725 }
4726
4727 static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info,
4728                                        struct btrfs_fs_info *fs_info,
4729                                        int flush_state)
4730 {
4731         u64 used;
4732
4733         spin_lock(&space_info->lock);
4734         /*
4735          * We run out of space and have not got any free space via flush_space,
4736          * so don't bother doing async reclaim.
4737          */
4738         if (flush_state > COMMIT_TRANS && space_info->full) {
4739                 spin_unlock(&space_info->lock);
4740                 return 0;
4741         }
4742
4743         used = space_info->bytes_used + space_info->bytes_reserved +
4744                space_info->bytes_pinned + space_info->bytes_readonly +
4745                space_info->bytes_may_use;
4746         if (need_do_async_reclaim(space_info, fs_info, used)) {
4747                 spin_unlock(&space_info->lock);
4748                 return 1;
4749         }
4750         spin_unlock(&space_info->lock);
4751
4752         return 0;
4753 }
4754
4755 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4756 {
4757         struct btrfs_fs_info *fs_info;
4758         struct btrfs_space_info *space_info;
4759         u64 to_reclaim;
4760         int flush_state;
4761
4762         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4763         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4764
4765         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4766                                                       space_info);
4767         if (!to_reclaim)
4768                 return;
4769
4770         flush_state = FLUSH_DELAYED_ITEMS_NR;
4771         do {
4772                 flush_space(fs_info->fs_root, space_info, to_reclaim,
4773                             to_reclaim, flush_state);
4774                 flush_state++;
4775                 if (!btrfs_need_do_async_reclaim(space_info, fs_info,
4776                                                  flush_state))
4777                         return;
4778         } while (flush_state < COMMIT_TRANS);
4779 }
4780
4781 void btrfs_init_async_reclaim_work(struct work_struct *work)
4782 {
4783         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
4784 }
4785
4786 /**
4787  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4788  * @root - the root we're allocating for
4789  * @block_rsv - the block_rsv we're allocating for
4790  * @orig_bytes - the number of bytes we want
4791  * @flush - whether or not we can flush to make our reservation
4792  *
4793  * This will reserve orgi_bytes number of bytes from the space info associated
4794  * with the block_rsv.  If there is not enough space it will make an attempt to
4795  * flush out space to make room.  It will do this by flushing delalloc if
4796  * possible or committing the transaction.  If flush is 0 then no attempts to
4797  * regain reservations will be made and this will fail if there is not enough
4798  * space already.
4799  */
4800 static int reserve_metadata_bytes(struct btrfs_root *root,
4801                                   struct btrfs_block_rsv *block_rsv,
4802                                   u64 orig_bytes,
4803                                   enum btrfs_reserve_flush_enum flush)
4804 {
4805         struct btrfs_space_info *space_info = block_rsv->space_info;
4806         u64 used;
4807         u64 num_bytes = orig_bytes;
4808         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4809         int ret = 0;
4810         bool flushing = false;
4811
4812 again:
4813         ret = 0;
4814         spin_lock(&space_info->lock);
4815         /*
4816          * We only want to wait if somebody other than us is flushing and we
4817          * are actually allowed to flush all things.
4818          */
4819         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4820                space_info->flush) {
4821                 spin_unlock(&space_info->lock);
4822                 /*
4823                  * If we have a trans handle we can't wait because the flusher
4824                  * may have to commit the transaction, which would mean we would
4825                  * deadlock since we are waiting for the flusher to finish, but
4826                  * hold the current transaction open.
4827                  */
4828                 if (current->journal_info)
4829                         return -EAGAIN;
4830                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4831                 /* Must have been killed, return */
4832                 if (ret)
4833                         return -EINTR;
4834
4835                 spin_lock(&space_info->lock);
4836         }
4837
4838         ret = -ENOSPC;
4839         used = space_info->bytes_used + space_info->bytes_reserved +
4840                 space_info->bytes_pinned + space_info->bytes_readonly +
4841                 space_info->bytes_may_use;
4842
4843         /*
4844          * The idea here is that we've not already over-reserved the block group
4845          * then we can go ahead and save our reservation first and then start
4846          * flushing if we need to.  Otherwise if we've already overcommitted
4847          * lets start flushing stuff first and then come back and try to make
4848          * our reservation.
4849          */
4850         if (used <= space_info->total_bytes) {
4851                 if (used + orig_bytes <= space_info->total_bytes) {
4852                         space_info->bytes_may_use += orig_bytes;
4853                         trace_btrfs_space_reservation(root->fs_info,
4854                                 "space_info", space_info->flags, orig_bytes, 1);
4855                         ret = 0;
4856                 } else {
4857                         /*
4858                          * Ok set num_bytes to orig_bytes since we aren't
4859                          * overocmmitted, this way we only try and reclaim what
4860                          * we need.
4861                          */
4862                         num_bytes = orig_bytes;
4863                 }
4864         } else {
4865                 /*
4866                  * Ok we're over committed, set num_bytes to the overcommitted
4867                  * amount plus the amount of bytes that we need for this
4868                  * reservation.
4869                  */
4870                 num_bytes = used - space_info->total_bytes +
4871                         (orig_bytes * 2);
4872         }
4873
4874         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4875                 space_info->bytes_may_use += orig_bytes;
4876                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4877                                               space_info->flags, orig_bytes,
4878                                               1);
4879                 ret = 0;
4880         }
4881
4882         /*
4883          * Couldn't make our reservation, save our place so while we're trying
4884          * to reclaim space we can actually use it instead of somebody else
4885          * stealing it from us.
4886          *
4887          * We make the other tasks wait for the flush only when we can flush
4888          * all things.
4889          */
4890         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4891                 flushing = true;
4892                 space_info->flush = 1;
4893         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
4894                 used += orig_bytes;
4895                 /*
4896                  * We will do the space reservation dance during log replay,
4897                  * which means we won't have fs_info->fs_root set, so don't do
4898                  * the async reclaim as we will panic.
4899                  */
4900                 if (!root->fs_info->log_root_recovering &&
4901                     need_do_async_reclaim(space_info, root->fs_info, used) &&
4902                     !work_busy(&root->fs_info->async_reclaim_work))
4903                         queue_work(system_unbound_wq,
4904                                    &root->fs_info->async_reclaim_work);
4905         }
4906         spin_unlock(&space_info->lock);
4907
4908         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4909                 goto out;
4910
4911         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4912                           flush_state);
4913         flush_state++;
4914
4915         /*
4916          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4917          * would happen. So skip delalloc flush.
4918          */
4919         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4920             (flush_state == FLUSH_DELALLOC ||
4921              flush_state == FLUSH_DELALLOC_WAIT))
4922                 flush_state = ALLOC_CHUNK;
4923
4924         if (!ret)
4925                 goto again;
4926         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4927                  flush_state < COMMIT_TRANS)
4928                 goto again;
4929         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4930                  flush_state <= COMMIT_TRANS)
4931                 goto again;
4932
4933 out:
4934         if (ret == -ENOSPC &&
4935             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4936                 struct btrfs_block_rsv *global_rsv =
4937                         &root->fs_info->global_block_rsv;
4938
4939                 if (block_rsv != global_rsv &&
4940                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4941                         ret = 0;
4942         }
4943         if (ret == -ENOSPC)
4944                 trace_btrfs_space_reservation(root->fs_info,
4945                                               "space_info:enospc",
4946                                               space_info->flags, orig_bytes, 1);
4947         if (flushing) {
4948                 spin_lock(&space_info->lock);
4949                 space_info->flush = 0;
4950                 wake_up_all(&space_info->wait);
4951                 spin_unlock(&space_info->lock);
4952         }
4953         return ret;
4954 }
4955
4956 static struct btrfs_block_rsv *get_block_rsv(
4957                                         const struct btrfs_trans_handle *trans,
4958                                         const struct btrfs_root *root)
4959 {
4960         struct btrfs_block_rsv *block_rsv = NULL;
4961
4962         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4963             (root == root->fs_info->csum_root && trans->adding_csums) ||
4964              (root == root->fs_info->uuid_root))
4965                 block_rsv = trans->block_rsv;
4966
4967         if (!block_rsv)
4968                 block_rsv = root->block_rsv;
4969
4970         if (!block_rsv)
4971                 block_rsv = &root->fs_info->empty_block_rsv;
4972
4973         return block_rsv;
4974 }
4975
4976 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4977                                u64 num_bytes)
4978 {
4979         int ret = -ENOSPC;
4980         spin_lock(&block_rsv->lock);
4981         if (block_rsv->reserved >= num_bytes) {
4982                 block_rsv->reserved -= num_bytes;
4983                 if (block_rsv->reserved < block_rsv->size)
4984                         block_rsv->full = 0;
4985                 ret = 0;
4986         }
4987         spin_unlock(&block_rsv->lock);
4988         return ret;
4989 }
4990
4991 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4992                                 u64 num_bytes, int update_size)
4993 {
4994         spin_lock(&block_rsv->lock);
4995         block_rsv->reserved += num_bytes;
4996         if (update_size)
4997                 block_rsv->size += num_bytes;
4998         else if (block_rsv->reserved >= block_rsv->size)
4999                 block_rsv->full = 1;
5000         spin_unlock(&block_rsv->lock);
5001 }
5002
5003 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5004                              struct btrfs_block_rsv *dest, u64 num_bytes,
5005                              int min_factor)
5006 {
5007         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5008         u64 min_bytes;
5009
5010         if (global_rsv->space_info != dest->space_info)
5011                 return -ENOSPC;
5012
5013         spin_lock(&global_rsv->lock);
5014         min_bytes = div_factor(global_rsv->size, min_factor);
5015         if (global_rsv->reserved < min_bytes + num_bytes) {
5016                 spin_unlock(&global_rsv->lock);
5017                 return -ENOSPC;
5018         }
5019         global_rsv->reserved -= num_bytes;
5020         if (global_rsv->reserved < global_rsv->size)
5021                 global_rsv->full = 0;
5022         spin_unlock(&global_rsv->lock);
5023
5024         block_rsv_add_bytes(dest, num_bytes, 1);
5025         return 0;
5026 }
5027
5028 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5029                                     struct btrfs_block_rsv *block_rsv,
5030                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5031 {
5032         struct btrfs_space_info *space_info = block_rsv->space_info;
5033
5034         spin_lock(&block_rsv->lock);
5035         if (num_bytes == (u64)-1)
5036                 num_bytes = block_rsv->size;
5037         block_rsv->size -= num_bytes;
5038         if (block_rsv->reserved >= block_rsv->size) {
5039                 num_bytes = block_rsv->reserved - block_rsv->size;
5040                 block_rsv->reserved = block_rsv->size;
5041                 block_rsv->full = 1;
5042         } else {
5043                 num_bytes = 0;
5044         }
5045         spin_unlock(&block_rsv->lock);
5046
5047         if (num_bytes > 0) {
5048                 if (dest) {
5049                         spin_lock(&dest->lock);
5050                         if (!dest->full) {
5051                                 u64 bytes_to_add;
5052
5053                                 bytes_to_add = dest->size - dest->reserved;
5054                                 bytes_to_add = min(num_bytes, bytes_to_add);
5055                                 dest->reserved += bytes_to_add;
5056                                 if (dest->reserved >= dest->size)
5057                                         dest->full = 1;
5058                                 num_bytes -= bytes_to_add;
5059                         }
5060                         spin_unlock(&dest->lock);
5061                 }
5062                 if (num_bytes) {
5063                         spin_lock(&space_info->lock);
5064                         space_info->bytes_may_use -= num_bytes;
5065                         trace_btrfs_space_reservation(fs_info, "space_info",
5066                                         space_info->flags, num_bytes, 0);
5067                         spin_unlock(&space_info->lock);
5068                 }
5069         }
5070 }
5071
5072 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
5073                                    struct btrfs_block_rsv *dst, u64 num_bytes)
5074 {
5075         int ret;
5076
5077         ret = block_rsv_use_bytes(src, num_bytes);
5078         if (ret)
5079                 return ret;
5080
5081         block_rsv_add_bytes(dst, num_bytes, 1);
5082         return 0;
5083 }
5084
5085 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5086 {
5087         memset(rsv, 0, sizeof(*rsv));
5088         spin_lock_init(&rsv->lock);
5089         rsv->type = type;
5090 }
5091
5092 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5093                                               unsigned short type)
5094 {
5095         struct btrfs_block_rsv *block_rsv;
5096         struct btrfs_fs_info *fs_info = root->fs_info;
5097
5098         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5099         if (!block_rsv)
5100                 return NULL;
5101
5102         btrfs_init_block_rsv(block_rsv, type);
5103         block_rsv->space_info = __find_space_info(fs_info,
5104                                                   BTRFS_BLOCK_GROUP_METADATA);
5105         return block_rsv;
5106 }
5107
5108 void btrfs_free_block_rsv(struct btrfs_root *root,
5109                           struct btrfs_block_rsv *rsv)
5110 {
5111         if (!rsv)
5112                 return;
5113         btrfs_block_rsv_release(root, rsv, (u64)-1);
5114         kfree(rsv);
5115 }
5116
5117 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5118 {
5119         kfree(rsv);
5120 }
5121
5122 int btrfs_block_rsv_add(struct btrfs_root *root,
5123                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5124                         enum btrfs_reserve_flush_enum flush)
5125 {
5126         int ret;
5127
5128         if (num_bytes == 0)
5129                 return 0;
5130
5131         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5132         if (!ret) {
5133                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5134                 return 0;
5135         }
5136
5137         return ret;
5138 }
5139
5140 int btrfs_block_rsv_check(struct btrfs_root *root,
5141                           struct btrfs_block_rsv *block_rsv, int min_factor)
5142 {
5143         u64 num_bytes = 0;
5144         int ret = -ENOSPC;
5145
5146         if (!block_rsv)
5147                 return 0;
5148
5149         spin_lock(&block_rsv->lock);
5150         num_bytes = div_factor(block_rsv->size, min_factor);
5151         if (block_rsv->reserved >= num_bytes)
5152                 ret = 0;
5153         spin_unlock(&block_rsv->lock);
5154
5155         return ret;
5156 }
5157
5158 int btrfs_block_rsv_refill(struct btrfs_root *root,
5159                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5160                            enum btrfs_reserve_flush_enum flush)
5161 {
5162         u64 num_bytes = 0;
5163         int ret = -ENOSPC;
5164
5165         if (!block_rsv)
5166                 return 0;
5167
5168         spin_lock(&block_rsv->lock);
5169         num_bytes = min_reserved;
5170         if (block_rsv->reserved >= num_bytes)
5171                 ret = 0;
5172         else
5173                 num_bytes -= block_rsv->reserved;
5174         spin_unlock(&block_rsv->lock);
5175
5176         if (!ret)
5177                 return 0;
5178
5179         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5180         if (!ret) {
5181                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5182                 return 0;
5183         }
5184
5185         return ret;
5186 }
5187
5188 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
5189                             struct btrfs_block_rsv *dst_rsv,
5190                             u64 num_bytes)
5191 {
5192         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5193 }
5194
5195 void btrfs_block_rsv_release(struct btrfs_root *root,
5196                              struct btrfs_block_rsv *block_rsv,
5197                              u64 num_bytes)
5198 {
5199         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5200         if (global_rsv == block_rsv ||
5201             block_rsv->space_info != global_rsv->space_info)
5202                 global_rsv = NULL;
5203         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5204                                 num_bytes);
5205 }
5206
5207 /*
5208  * helper to calculate size of global block reservation.
5209  * the desired value is sum of space used by extent tree,
5210  * checksum tree and root tree
5211  */
5212 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
5213 {
5214         struct btrfs_space_info *sinfo;
5215         u64 num_bytes;
5216         u64 meta_used;
5217         u64 data_used;
5218         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
5219
5220         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
5221         spin_lock(&sinfo->lock);
5222         data_used = sinfo->bytes_used;
5223         spin_unlock(&sinfo->lock);
5224
5225         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5226         spin_lock(&sinfo->lock);
5227         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
5228                 data_used = 0;
5229         meta_used = sinfo->bytes_used;
5230         spin_unlock(&sinfo->lock);
5231
5232         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
5233                     csum_size * 2;
5234         num_bytes += div_u64(data_used + meta_used, 50);
5235
5236         if (num_bytes * 3 > meta_used)
5237                 num_bytes = div_u64(meta_used, 3);
5238
5239         return ALIGN(num_bytes, fs_info->extent_root->nodesize << 10);
5240 }
5241
5242 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5243 {
5244         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5245         struct btrfs_space_info *sinfo = block_rsv->space_info;
5246         u64 num_bytes;
5247
5248         num_bytes = calc_global_metadata_size(fs_info);
5249
5250         spin_lock(&sinfo->lock);
5251         spin_lock(&block_rsv->lock);
5252
5253         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
5254
5255         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5256                     sinfo->bytes_reserved + sinfo->bytes_readonly +
5257                     sinfo->bytes_may_use;
5258
5259         if (sinfo->total_bytes > num_bytes) {
5260                 num_bytes = sinfo->total_bytes - num_bytes;
5261                 block_rsv->reserved += num_bytes;
5262                 sinfo->bytes_may_use += num_bytes;
5263                 trace_btrfs_space_reservation(fs_info, "space_info",
5264                                       sinfo->flags, num_bytes, 1);
5265         }
5266
5267         if (block_rsv->reserved >= block_rsv->size) {
5268                 num_bytes = block_rsv->reserved - block_rsv->size;
5269                 sinfo->bytes_may_use -= num_bytes;
5270                 trace_btrfs_space_reservation(fs_info, "space_info",
5271                                       sinfo->flags, num_bytes, 0);
5272                 block_rsv->reserved = block_rsv->size;
5273                 block_rsv->full = 1;
5274         }
5275
5276         spin_unlock(&block_rsv->lock);
5277         spin_unlock(&sinfo->lock);
5278 }
5279
5280 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5281 {
5282         struct btrfs_space_info *space_info;
5283
5284         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5285         fs_info->chunk_block_rsv.space_info = space_info;
5286
5287         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5288         fs_info->global_block_rsv.space_info = space_info;
5289         fs_info->delalloc_block_rsv.space_info = space_info;
5290         fs_info->trans_block_rsv.space_info = space_info;
5291         fs_info->empty_block_rsv.space_info = space_info;
5292         fs_info->delayed_block_rsv.space_info = space_info;
5293
5294         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5295         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5296         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5297         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5298         if (fs_info->quota_root)
5299                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5300         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5301
5302         update_global_block_rsv(fs_info);
5303 }
5304
5305 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5306 {
5307         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5308                                 (u64)-1);
5309         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5310         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5311         WARN_ON(fs_info->trans_block_rsv.size > 0);
5312         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5313         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5314         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5315         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5316         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5317 }
5318
5319 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5320                                   struct btrfs_root *root)
5321 {
5322         if (!trans->block_rsv)
5323                 return;
5324
5325         if (!trans->bytes_reserved)
5326                 return;
5327
5328         trace_btrfs_space_reservation(root->fs_info, "transaction",
5329                                       trans->transid, trans->bytes_reserved, 0);
5330         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5331         trans->bytes_reserved = 0;
5332 }
5333
5334 /*
5335  * To be called after all the new block groups attached to the transaction
5336  * handle have been created (btrfs_create_pending_block_groups()).
5337  */
5338 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5339 {
5340         struct btrfs_fs_info *fs_info = trans->root->fs_info;
5341
5342         if (!trans->chunk_bytes_reserved)
5343                 return;
5344
5345         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5346
5347         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5348                                 trans->chunk_bytes_reserved);
5349         trans->chunk_bytes_reserved = 0;
5350 }
5351
5352 /* Can only return 0 or -ENOSPC */
5353 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5354                                   struct inode *inode)
5355 {
5356         struct btrfs_root *root = BTRFS_I(inode)->root;
5357         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
5358         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5359
5360         /*
5361          * We need to hold space in order to delete our orphan item once we've
5362          * added it, so this takes the reservation so we can release it later
5363          * when we are truly done with the orphan item.
5364          */
5365         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5366         trace_btrfs_space_reservation(root->fs_info, "orphan",
5367                                       btrfs_ino(inode), num_bytes, 1);
5368         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5369 }
5370
5371 void btrfs_orphan_release_metadata(struct inode *inode)
5372 {
5373         struct btrfs_root *root = BTRFS_I(inode)->root;
5374         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5375         trace_btrfs_space_reservation(root->fs_info, "orphan",
5376                                       btrfs_ino(inode), num_bytes, 0);
5377         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5378 }
5379
5380 /*
5381  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5382  * root: the root of the parent directory
5383  * rsv: block reservation
5384  * items: the number of items that we need do reservation
5385  * qgroup_reserved: used to return the reserved size in qgroup
5386  *
5387  * This function is used to reserve the space for snapshot/subvolume
5388  * creation and deletion. Those operations are different with the
5389  * common file/directory operations, they change two fs/file trees
5390  * and root tree, the number of items that the qgroup reserves is
5391  * different with the free space reservation. So we can not use
5392  * the space reseravtion mechanism in start_transaction().
5393  */
5394 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5395                                      struct btrfs_block_rsv *rsv,
5396                                      int items,
5397                                      u64 *qgroup_reserved,
5398                                      bool use_global_rsv)
5399 {
5400         u64 num_bytes;
5401         int ret;
5402         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5403
5404         if (root->fs_info->quota_enabled) {
5405                 /* One for parent inode, two for dir entries */
5406                 num_bytes = 3 * root->nodesize;
5407                 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5408                 if (ret)
5409                         return ret;
5410         } else {
5411                 num_bytes = 0;
5412         }
5413
5414         *qgroup_reserved = num_bytes;
5415
5416         num_bytes = btrfs_calc_trans_metadata_size(root, items);
5417         rsv->space_info = __find_space_info(root->fs_info,
5418                                             BTRFS_BLOCK_GROUP_METADATA);
5419         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5420                                   BTRFS_RESERVE_FLUSH_ALL);
5421
5422         if (ret == -ENOSPC && use_global_rsv)
5423                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
5424
5425         if (ret && *qgroup_reserved)
5426                 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5427
5428         return ret;
5429 }
5430
5431 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5432                                       struct btrfs_block_rsv *rsv,
5433                                       u64 qgroup_reserved)
5434 {
5435         btrfs_block_rsv_release(root, rsv, (u64)-1);
5436 }
5437
5438 /**
5439  * drop_outstanding_extent - drop an outstanding extent
5440  * @inode: the inode we're dropping the extent for
5441  * @num_bytes: the number of bytes we're relaseing.
5442  *
5443  * This is called when we are freeing up an outstanding extent, either called
5444  * after an error or after an extent is written.  This will return the number of
5445  * reserved extents that need to be freed.  This must be called with
5446  * BTRFS_I(inode)->lock held.
5447  */
5448 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5449 {
5450         unsigned drop_inode_space = 0;
5451         unsigned dropped_extents = 0;
5452         unsigned num_extents = 0;
5453
5454         num_extents = (unsigned)div64_u64(num_bytes +
5455                                           BTRFS_MAX_EXTENT_SIZE - 1,
5456                                           BTRFS_MAX_EXTENT_SIZE);
5457         ASSERT(num_extents);
5458         ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5459         BTRFS_I(inode)->outstanding_extents -= num_extents;
5460
5461         if (BTRFS_I(inode)->outstanding_extents == 0 &&
5462             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5463                                &BTRFS_I(inode)->runtime_flags))
5464                 drop_inode_space = 1;
5465
5466         /*
5467          * If we have more or the same amount of outsanding extents than we have
5468          * reserved then we need to leave the reserved extents count alone.
5469          */
5470         if (BTRFS_I(inode)->outstanding_extents >=
5471             BTRFS_I(inode)->reserved_extents)
5472                 return drop_inode_space;
5473
5474         dropped_extents = BTRFS_I(inode)->reserved_extents -
5475                 BTRFS_I(inode)->outstanding_extents;
5476         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5477         return dropped_extents + drop_inode_space;
5478 }
5479
5480 /**
5481  * calc_csum_metadata_size - return the amount of metada space that must be
5482  *      reserved/free'd for the given bytes.
5483  * @inode: the inode we're manipulating
5484  * @num_bytes: the number of bytes in question
5485  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5486  *
5487  * This adjusts the number of csum_bytes in the inode and then returns the
5488  * correct amount of metadata that must either be reserved or freed.  We
5489  * calculate how many checksums we can fit into one leaf and then divide the
5490  * number of bytes that will need to be checksumed by this value to figure out
5491  * how many checksums will be required.  If we are adding bytes then the number
5492  * may go up and we will return the number of additional bytes that must be
5493  * reserved.  If it is going down we will return the number of bytes that must
5494  * be freed.
5495  *
5496  * This must be called with BTRFS_I(inode)->lock held.
5497  */
5498 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5499                                    int reserve)
5500 {
5501         struct btrfs_root *root = BTRFS_I(inode)->root;
5502         u64 old_csums, num_csums;
5503
5504         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5505             BTRFS_I(inode)->csum_bytes == 0)
5506                 return 0;
5507
5508         old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5509         if (reserve)
5510                 BTRFS_I(inode)->csum_bytes += num_bytes;
5511         else
5512                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5513         num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5514
5515         /* No change, no need to reserve more */
5516         if (old_csums == num_csums)
5517                 return 0;
5518
5519         if (reserve)
5520                 return btrfs_calc_trans_metadata_size(root,
5521                                                       num_csums - old_csums);
5522
5523         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5524 }
5525
5526 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5527 {
5528         struct btrfs_root *root = BTRFS_I(inode)->root;
5529         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5530         u64 to_reserve = 0;
5531         u64 csum_bytes;
5532         unsigned nr_extents = 0;
5533         int extra_reserve = 0;
5534         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5535         int ret = 0;
5536         bool delalloc_lock = true;
5537         u64 to_free = 0;
5538         unsigned dropped;
5539
5540         /* If we are a free space inode we need to not flush since we will be in
5541          * the middle of a transaction commit.  We also don't need the delalloc
5542          * mutex since we won't race with anybody.  We need this mostly to make
5543          * lockdep shut its filthy mouth.
5544          */
5545         if (btrfs_is_free_space_inode(inode)) {
5546                 flush = BTRFS_RESERVE_NO_FLUSH;
5547                 delalloc_lock = false;
5548         }
5549
5550         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5551             btrfs_transaction_in_commit(root->fs_info))
5552                 schedule_timeout(1);
5553
5554         if (delalloc_lock)
5555                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5556
5557         num_bytes = ALIGN(num_bytes, root->sectorsize);
5558
5559         spin_lock(&BTRFS_I(inode)->lock);
5560         nr_extents = (unsigned)div64_u64(num_bytes +
5561                                          BTRFS_MAX_EXTENT_SIZE - 1,
5562                                          BTRFS_MAX_EXTENT_SIZE);
5563         BTRFS_I(inode)->outstanding_extents += nr_extents;
5564         nr_extents = 0;
5565
5566         if (BTRFS_I(inode)->outstanding_extents >
5567             BTRFS_I(inode)->reserved_extents)
5568                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5569                         BTRFS_I(inode)->reserved_extents;
5570
5571         /*
5572          * Add an item to reserve for updating the inode when we complete the
5573          * delalloc io.
5574          */
5575         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5576                       &BTRFS_I(inode)->runtime_flags)) {
5577                 nr_extents++;
5578                 extra_reserve = 1;
5579         }
5580
5581         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5582         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5583         csum_bytes = BTRFS_I(inode)->csum_bytes;
5584         spin_unlock(&BTRFS_I(inode)->lock);
5585
5586         if (root->fs_info->quota_enabled) {
5587                 ret = btrfs_qgroup_reserve_meta(root,
5588                                 nr_extents * root->nodesize);
5589                 if (ret)
5590                         goto out_fail;
5591         }
5592
5593         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5594         if (unlikely(ret)) {
5595                 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5596                 goto out_fail;
5597         }
5598
5599         spin_lock(&BTRFS_I(inode)->lock);
5600         if (extra_reserve) {
5601                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5602                         &BTRFS_I(inode)->runtime_flags);
5603                 nr_extents--;
5604         }
5605         BTRFS_I(inode)->reserved_extents += nr_extents;
5606         spin_unlock(&BTRFS_I(inode)->lock);
5607
5608         if (delalloc_lock)
5609                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5610
5611         if (to_reserve)
5612                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5613                                               btrfs_ino(inode), to_reserve, 1);
5614         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5615
5616         return 0;
5617
5618 out_fail:
5619         spin_lock(&BTRFS_I(inode)->lock);
5620         dropped = drop_outstanding_extent(inode, num_bytes);
5621         /*
5622          * If the inodes csum_bytes is the same as the original
5623          * csum_bytes then we know we haven't raced with any free()ers
5624          * so we can just reduce our inodes csum bytes and carry on.
5625          */
5626         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5627                 calc_csum_metadata_size(inode, num_bytes, 0);
5628         } else {
5629                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5630                 u64 bytes;
5631
5632                 /*
5633                  * This is tricky, but first we need to figure out how much we
5634                  * free'd from any free-ers that occured during this
5635                  * reservation, so we reset ->csum_bytes to the csum_bytes
5636                  * before we dropped our lock, and then call the free for the
5637                  * number of bytes that were freed while we were trying our
5638                  * reservation.
5639                  */
5640                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5641                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5642                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5643
5644
5645                 /*
5646                  * Now we need to see how much we would have freed had we not
5647                  * been making this reservation and our ->csum_bytes were not
5648                  * artificially inflated.
5649                  */
5650                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5651                 bytes = csum_bytes - orig_csum_bytes;
5652                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5653
5654                 /*
5655                  * Now reset ->csum_bytes to what it should be.  If bytes is
5656                  * more than to_free then we would have free'd more space had we
5657                  * not had an artificially high ->csum_bytes, so we need to free
5658                  * the remainder.  If bytes is the same or less then we don't
5659                  * need to do anything, the other free-ers did the correct
5660                  * thing.
5661                  */
5662                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5663                 if (bytes > to_free)
5664                         to_free = bytes - to_free;
5665                 else
5666                         to_free = 0;
5667         }
5668         spin_unlock(&BTRFS_I(inode)->lock);
5669         if (dropped)
5670                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5671
5672         if (to_free) {
5673                 btrfs_block_rsv_release(root, block_rsv, to_free);
5674                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5675                                               btrfs_ino(inode), to_free, 0);
5676         }
5677         if (delalloc_lock)
5678                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5679         return ret;
5680 }
5681
5682 /**
5683  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5684  * @inode: the inode to release the reservation for
5685  * @num_bytes: the number of bytes we're releasing
5686  *
5687  * This will release the metadata reservation for an inode.  This can be called
5688  * once we complete IO for a given set of bytes to release their metadata
5689  * reservations.
5690  */
5691 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5692 {
5693         struct btrfs_root *root = BTRFS_I(inode)->root;
5694         u64 to_free = 0;
5695         unsigned dropped;
5696
5697         num_bytes = ALIGN(num_bytes, root->sectorsize);
5698         spin_lock(&BTRFS_I(inode)->lock);
5699         dropped = drop_outstanding_extent(inode, num_bytes);
5700
5701         if (num_bytes)
5702                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5703         spin_unlock(&BTRFS_I(inode)->lock);
5704         if (dropped > 0)
5705                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5706
5707         if (btrfs_test_is_dummy_root(root))
5708                 return;
5709
5710         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5711                                       btrfs_ino(inode), to_free, 0);
5712
5713         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5714                                 to_free);
5715 }
5716
5717 /**
5718  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5719  * @inode: inode we're writing to
5720  * @num_bytes: the number of bytes we want to allocate
5721  *
5722  * This will do the following things
5723  *
5724  * o reserve space in the data space info for num_bytes
5725  * o reserve space in the metadata space info based on number of outstanding
5726  *   extents and how much csums will be needed
5727  * o add to the inodes ->delalloc_bytes
5728  * o add it to the fs_info's delalloc inodes list.
5729  *
5730  * This will return 0 for success and -ENOSPC if there is no space left.
5731  */
5732 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5733 {
5734         int ret;
5735
5736         ret = btrfs_check_data_free_space(inode, num_bytes, num_bytes);
5737         if (ret)
5738                 return ret;
5739
5740         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5741         if (ret) {
5742                 btrfs_free_reserved_data_space(inode, num_bytes);
5743                 return ret;
5744         }
5745
5746         return 0;
5747 }
5748
5749 /**
5750  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5751  * @inode: inode we're releasing space for
5752  * @num_bytes: the number of bytes we want to free up
5753  *
5754  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5755  * called in the case that we don't need the metadata AND data reservations
5756  * anymore.  So if there is an error or we insert an inline extent.
5757  *
5758  * This function will release the metadata space that was not used and will
5759  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5760  * list if there are no delalloc bytes left.
5761  */
5762 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5763 {
5764         btrfs_delalloc_release_metadata(inode, num_bytes);
5765         btrfs_free_reserved_data_space(inode, num_bytes);
5766 }
5767
5768 static int update_block_group(struct btrfs_trans_handle *trans,
5769                               struct btrfs_root *root, u64 bytenr,
5770                               u64 num_bytes, int alloc)
5771 {
5772         struct btrfs_block_group_cache *cache = NULL;
5773         struct btrfs_fs_info *info = root->fs_info;
5774         u64 total = num_bytes;
5775         u64 old_val;
5776         u64 byte_in_group;
5777         int factor;
5778
5779         /* block accounting for super block */
5780         spin_lock(&info->delalloc_root_lock);
5781         old_val = btrfs_super_bytes_used(info->super_copy);
5782         if (alloc)
5783                 old_val += num_bytes;
5784         else
5785                 old_val -= num_bytes;
5786         btrfs_set_super_bytes_used(info->super_copy, old_val);
5787         spin_unlock(&info->delalloc_root_lock);
5788
5789         while (total) {
5790                 cache = btrfs_lookup_block_group(info, bytenr);
5791                 if (!cache)
5792                         return -ENOENT;
5793                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5794                                     BTRFS_BLOCK_GROUP_RAID1 |
5795                                     BTRFS_BLOCK_GROUP_RAID10))
5796                         factor = 2;
5797                 else
5798                         factor = 1;
5799                 /*
5800                  * If this block group has free space cache written out, we
5801                  * need to make sure to load it if we are removing space.  This
5802                  * is because we need the unpinning stage to actually add the
5803                  * space back to the block group, otherwise we will leak space.
5804                  */
5805                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5806                         cache_block_group(cache, 1);
5807
5808                 byte_in_group = bytenr - cache->key.objectid;
5809                 WARN_ON(byte_in_group > cache->key.offset);
5810
5811                 spin_lock(&cache->space_info->lock);
5812                 spin_lock(&cache->lock);
5813
5814                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5815                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5816                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5817
5818                 old_val = btrfs_block_group_used(&cache->item);
5819                 num_bytes = min(total, cache->key.offset - byte_in_group);
5820                 if (alloc) {
5821                         old_val += num_bytes;
5822                         btrfs_set_block_group_used(&cache->item, old_val);
5823                         cache->reserved -= num_bytes;
5824                         cache->space_info->bytes_reserved -= num_bytes;
5825                         cache->space_info->bytes_used += num_bytes;
5826                         cache->space_info->disk_used += num_bytes * factor;
5827                         spin_unlock(&cache->lock);
5828                         spin_unlock(&cache->space_info->lock);
5829                 } else {
5830                         old_val -= num_bytes;
5831                         btrfs_set_block_group_used(&cache->item, old_val);
5832                         cache->pinned += num_bytes;
5833                         cache->space_info->bytes_pinned += num_bytes;
5834                         cache->space_info->bytes_used -= num_bytes;
5835                         cache->space_info->disk_used -= num_bytes * factor;
5836                         spin_unlock(&cache->lock);
5837                         spin_unlock(&cache->space_info->lock);
5838
5839                         set_extent_dirty(info->pinned_extents,
5840                                          bytenr, bytenr + num_bytes - 1,
5841                                          GFP_NOFS | __GFP_NOFAIL);
5842                         /*
5843                          * No longer have used bytes in this block group, queue
5844                          * it for deletion.
5845                          */
5846                         if (old_val == 0) {
5847                                 spin_lock(&info->unused_bgs_lock);
5848                                 if (list_empty(&cache->bg_list)) {
5849                                         btrfs_get_block_group(cache);
5850                                         list_add_tail(&cache->bg_list,
5851                                                       &info->unused_bgs);
5852                                 }
5853                                 spin_unlock(&info->unused_bgs_lock);
5854                         }
5855                 }
5856
5857                 spin_lock(&trans->transaction->dirty_bgs_lock);
5858                 if (list_empty(&cache->dirty_list)) {
5859                         list_add_tail(&cache->dirty_list,
5860                                       &trans->transaction->dirty_bgs);
5861                                 trans->transaction->num_dirty_bgs++;
5862                         btrfs_get_block_group(cache);
5863                 }
5864                 spin_unlock(&trans->transaction->dirty_bgs_lock);
5865
5866                 btrfs_put_block_group(cache);
5867                 total -= num_bytes;
5868                 bytenr += num_bytes;
5869         }
5870         return 0;
5871 }
5872
5873 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5874 {
5875         struct btrfs_block_group_cache *cache;
5876         u64 bytenr;
5877
5878         spin_lock(&root->fs_info->block_group_cache_lock);
5879         bytenr = root->fs_info->first_logical_byte;
5880         spin_unlock(&root->fs_info->block_group_cache_lock);
5881
5882         if (bytenr < (u64)-1)
5883                 return bytenr;
5884
5885         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5886         if (!cache)
5887                 return 0;
5888
5889         bytenr = cache->key.objectid;
5890         btrfs_put_block_group(cache);
5891
5892         return bytenr;
5893 }
5894
5895 static int pin_down_extent(struct btrfs_root *root,
5896                            struct btrfs_block_group_cache *cache,
5897                            u64 bytenr, u64 num_bytes, int reserved)
5898 {
5899         spin_lock(&cache->space_info->lock);
5900         spin_lock(&cache->lock);
5901         cache->pinned += num_bytes;
5902         cache->space_info->bytes_pinned += num_bytes;
5903         if (reserved) {
5904                 cache->reserved -= num_bytes;
5905                 cache->space_info->bytes_reserved -= num_bytes;
5906         }
5907         spin_unlock(&cache->lock);
5908         spin_unlock(&cache->space_info->lock);
5909
5910         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5911                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5912         if (reserved)
5913                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5914         return 0;
5915 }
5916
5917 /*
5918  * this function must be called within transaction
5919  */
5920 int btrfs_pin_extent(struct btrfs_root *root,
5921                      u64 bytenr, u64 num_bytes, int reserved)
5922 {
5923         struct btrfs_block_group_cache *cache;
5924
5925         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5926         BUG_ON(!cache); /* Logic error */
5927
5928         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5929
5930         btrfs_put_block_group(cache);
5931         return 0;
5932 }
5933
5934 /*
5935  * this function must be called within transaction
5936  */
5937 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5938                                     u64 bytenr, u64 num_bytes)
5939 {
5940         struct btrfs_block_group_cache *cache;
5941         int ret;
5942
5943         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5944         if (!cache)
5945                 return -EINVAL;
5946
5947         /*
5948          * pull in the free space cache (if any) so that our pin
5949          * removes the free space from the cache.  We have load_only set
5950          * to one because the slow code to read in the free extents does check
5951          * the pinned extents.
5952          */
5953         cache_block_group(cache, 1);
5954
5955         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5956
5957         /* remove us from the free space cache (if we're there at all) */
5958         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5959         btrfs_put_block_group(cache);
5960         return ret;
5961 }
5962
5963 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5964 {
5965         int ret;
5966         struct btrfs_block_group_cache *block_group;
5967         struct btrfs_caching_control *caching_ctl;
5968
5969         block_group = btrfs_lookup_block_group(root->fs_info, start);
5970         if (!block_group)
5971                 return -EINVAL;
5972
5973         cache_block_group(block_group, 0);
5974         caching_ctl = get_caching_control(block_group);
5975
5976         if (!caching_ctl) {
5977                 /* Logic error */
5978                 BUG_ON(!block_group_cache_done(block_group));
5979                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5980         } else {
5981                 mutex_lock(&caching_ctl->mutex);
5982
5983                 if (start >= caching_ctl->progress) {
5984                         ret = add_excluded_extent(root, start, num_bytes);
5985                 } else if (start + num_bytes <= caching_ctl->progress) {
5986                         ret = btrfs_remove_free_space(block_group,
5987                                                       start, num_bytes);
5988                 } else {
5989                         num_bytes = caching_ctl->progress - start;
5990                         ret = btrfs_remove_free_space(block_group,
5991                                                       start, num_bytes);
5992                         if (ret)
5993                                 goto out_lock;
5994
5995                         num_bytes = (start + num_bytes) -
5996                                 caching_ctl->progress;
5997                         start = caching_ctl->progress;
5998                         ret = add_excluded_extent(root, start, num_bytes);
5999                 }
6000 out_lock:
6001                 mutex_unlock(&caching_ctl->mutex);
6002                 put_caching_control(caching_ctl);
6003         }
6004         btrfs_put_block_group(block_group);
6005         return ret;
6006 }
6007
6008 int btrfs_exclude_logged_extents(struct btrfs_root *log,
6009                                  struct extent_buffer *eb)
6010 {
6011         struct btrfs_file_extent_item *item;
6012         struct btrfs_key key;
6013         int found_type;
6014         int i;
6015
6016         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6017                 return 0;
6018
6019         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6020                 btrfs_item_key_to_cpu(eb, &key, i);
6021                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6022                         continue;
6023                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6024                 found_type = btrfs_file_extent_type(eb, item);
6025                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6026                         continue;
6027                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6028                         continue;
6029                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6030                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6031                 __exclude_logged_extent(log, key.objectid, key.offset);
6032         }
6033
6034         return 0;
6035 }
6036
6037 /**
6038  * btrfs_update_reserved_bytes - update the block_group and space info counters
6039  * @cache:      The cache we are manipulating
6040  * @num_bytes:  The number of bytes in question
6041  * @reserve:    One of the reservation enums
6042  * @delalloc:   The blocks are allocated for the delalloc write
6043  *
6044  * This is called by the allocator when it reserves space, or by somebody who is
6045  * freeing space that was never actually used on disk.  For example if you
6046  * reserve some space for a new leaf in transaction A and before transaction A
6047  * commits you free that leaf, you call this with reserve set to 0 in order to
6048  * clear the reservation.
6049  *
6050  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
6051  * ENOSPC accounting.  For data we handle the reservation through clearing the
6052  * delalloc bits in the io_tree.  We have to do this since we could end up
6053  * allocating less disk space for the amount of data we have reserved in the
6054  * case of compression.
6055  *
6056  * If this is a reservation and the block group has become read only we cannot
6057  * make the reservation and return -EAGAIN, otherwise this function always
6058  * succeeds.
6059  */
6060 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
6061                                        u64 num_bytes, int reserve, int delalloc)
6062 {
6063         struct btrfs_space_info *space_info = cache->space_info;
6064         int ret = 0;
6065
6066         spin_lock(&space_info->lock);
6067         spin_lock(&cache->lock);
6068         if (reserve != RESERVE_FREE) {
6069                 if (cache->ro) {
6070                         ret = -EAGAIN;
6071                 } else {
6072                         cache->reserved += num_bytes;
6073                         space_info->bytes_reserved += num_bytes;
6074                         if (reserve == RESERVE_ALLOC) {
6075                                 trace_btrfs_space_reservation(cache->fs_info,
6076                                                 "space_info", space_info->flags,
6077                                                 num_bytes, 0);
6078                                 space_info->bytes_may_use -= num_bytes;
6079                         }
6080
6081                         if (delalloc)
6082                                 cache->delalloc_bytes += num_bytes;
6083                 }
6084         } else {
6085                 if (cache->ro)
6086                         space_info->bytes_readonly += num_bytes;
6087                 cache->reserved -= num_bytes;
6088                 space_info->bytes_reserved -= num_bytes;
6089
6090                 if (delalloc)
6091                         cache->delalloc_bytes -= num_bytes;
6092         }
6093         spin_unlock(&cache->lock);
6094         spin_unlock(&space_info->lock);
6095         return ret;
6096 }
6097
6098 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6099                                 struct btrfs_root *root)
6100 {
6101         struct btrfs_fs_info *fs_info = root->fs_info;
6102         struct btrfs_caching_control *next;
6103         struct btrfs_caching_control *caching_ctl;
6104         struct btrfs_block_group_cache *cache;
6105
6106         down_write(&fs_info->commit_root_sem);
6107
6108         list_for_each_entry_safe(caching_ctl, next,
6109                                  &fs_info->caching_block_groups, list) {
6110                 cache = caching_ctl->block_group;
6111                 if (block_group_cache_done(cache)) {
6112                         cache->last_byte_to_unpin = (u64)-1;
6113                         list_del_init(&caching_ctl->list);
6114                         put_caching_control(caching_ctl);
6115                 } else {
6116                         cache->last_byte_to_unpin = caching_ctl->progress;
6117                 }
6118         }
6119
6120         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6121                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6122         else
6123                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6124
6125         up_write(&fs_info->commit_root_sem);
6126
6127         update_global_block_rsv(fs_info);
6128 }
6129
6130 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6131                               const bool return_free_space)
6132 {
6133         struct btrfs_fs_info *fs_info = root->fs_info;
6134         struct btrfs_block_group_cache *cache = NULL;
6135         struct btrfs_space_info *space_info;
6136         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6137         u64 len;
6138         bool readonly;
6139
6140         while (start <= end) {
6141                 readonly = false;
6142                 if (!cache ||
6143                     start >= cache->key.objectid + cache->key.offset) {
6144                         if (cache)
6145                                 btrfs_put_block_group(cache);
6146                         cache = btrfs_lookup_block_group(fs_info, start);
6147                         BUG_ON(!cache); /* Logic error */
6148                 }
6149
6150                 len = cache->key.objectid + cache->key.offset - start;
6151                 len = min(len, end + 1 - start);
6152
6153                 if (start < cache->last_byte_to_unpin) {
6154                         len = min(len, cache->last_byte_to_unpin - start);
6155                         if (return_free_space)
6156                                 btrfs_add_free_space(cache, start, len);
6157                 }
6158
6159                 start += len;
6160                 space_info = cache->space_info;
6161
6162                 spin_lock(&space_info->lock);
6163                 spin_lock(&cache->lock);
6164                 cache->pinned -= len;
6165                 space_info->bytes_pinned -= len;
6166                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6167                 if (cache->ro) {
6168                         space_info->bytes_readonly += len;
6169                         readonly = true;
6170                 }
6171                 spin_unlock(&cache->lock);
6172                 if (!readonly && global_rsv->space_info == space_info) {
6173                         spin_lock(&global_rsv->lock);
6174                         if (!global_rsv->full) {
6175                                 len = min(len, global_rsv->size -
6176                                           global_rsv->reserved);
6177                                 global_rsv->reserved += len;
6178                                 space_info->bytes_may_use += len;
6179                                 if (global_rsv->reserved >= global_rsv->size)
6180                                         global_rsv->full = 1;
6181                         }
6182                         spin_unlock(&global_rsv->lock);
6183                 }
6184                 spin_unlock(&space_info->lock);
6185         }
6186
6187         if (cache)
6188                 btrfs_put_block_group(cache);
6189         return 0;
6190 }
6191
6192 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6193                                struct btrfs_root *root)
6194 {
6195         struct btrfs_fs_info *fs_info = root->fs_info;
6196         struct btrfs_block_group_cache *block_group, *tmp;
6197         struct list_head *deleted_bgs;
6198         struct extent_io_tree *unpin;
6199         u64 start;
6200         u64 end;
6201         int ret;
6202
6203         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6204                 unpin = &fs_info->freed_extents[1];
6205         else
6206                 unpin = &fs_info->freed_extents[0];
6207
6208         while (!trans->aborted) {
6209                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6210                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6211                                             EXTENT_DIRTY, NULL);
6212                 if (ret) {
6213                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6214                         break;
6215                 }
6216
6217                 if (btrfs_test_opt(root, DISCARD))
6218                         ret = btrfs_discard_extent(root, start,
6219                                                    end + 1 - start, NULL);
6220
6221                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
6222                 unpin_extent_range(root, start, end, true);
6223                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6224                 cond_resched();
6225         }
6226
6227         /*
6228          * Transaction is finished.  We don't need the lock anymore.  We
6229          * do need to clean up the block groups in case of a transaction
6230          * abort.
6231          */
6232         deleted_bgs = &trans->transaction->deleted_bgs;
6233         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6234                 u64 trimmed = 0;
6235
6236                 ret = -EROFS;
6237                 if (!trans->aborted)
6238                         ret = btrfs_discard_extent(root,
6239                                                    block_group->key.objectid,
6240                                                    block_group->key.offset,
6241                                                    &trimmed);
6242
6243                 list_del_init(&block_group->bg_list);
6244                 btrfs_put_block_group_trimming(block_group);
6245                 btrfs_put_block_group(block_group);
6246
6247                 if (ret) {
6248                         const char *errstr = btrfs_decode_error(ret);
6249                         btrfs_warn(fs_info,
6250                                    "Discard failed while removing blockgroup: errno=%d %s\n",
6251                                    ret, errstr);
6252                 }
6253         }
6254
6255         return 0;
6256 }
6257
6258 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6259                              u64 owner, u64 root_objectid)
6260 {
6261         struct btrfs_space_info *space_info;
6262         u64 flags;
6263
6264         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6265                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6266                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
6267                 else
6268                         flags = BTRFS_BLOCK_GROUP_METADATA;
6269         } else {
6270                 flags = BTRFS_BLOCK_GROUP_DATA;
6271         }
6272
6273         space_info = __find_space_info(fs_info, flags);
6274         BUG_ON(!space_info); /* Logic bug */
6275         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6276 }
6277
6278
6279 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6280                                 struct btrfs_root *root,
6281                                 struct btrfs_delayed_ref_node *node, u64 parent,
6282                                 u64 root_objectid, u64 owner_objectid,
6283                                 u64 owner_offset, int refs_to_drop,
6284                                 struct btrfs_delayed_extent_op *extent_op)
6285 {
6286         struct btrfs_key key;
6287         struct btrfs_path *path;
6288         struct btrfs_fs_info *info = root->fs_info;
6289         struct btrfs_root *extent_root = info->extent_root;
6290         struct extent_buffer *leaf;
6291         struct btrfs_extent_item *ei;
6292         struct btrfs_extent_inline_ref *iref;
6293         int ret;
6294         int is_data;
6295         int extent_slot = 0;
6296         int found_extent = 0;
6297         int num_to_del = 1;
6298         int no_quota = node->no_quota;
6299         u32 item_size;
6300         u64 refs;
6301         u64 bytenr = node->bytenr;
6302         u64 num_bytes = node->num_bytes;
6303         int last_ref = 0;
6304         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6305                                                  SKINNY_METADATA);
6306
6307         if (!info->quota_enabled || !is_fstree(root_objectid))
6308                 no_quota = 1;
6309
6310         path = btrfs_alloc_path();
6311         if (!path)
6312                 return -ENOMEM;
6313
6314         path->reada = 1;
6315         path->leave_spinning = 1;
6316
6317         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6318         BUG_ON(!is_data && refs_to_drop != 1);
6319
6320         if (is_data)
6321                 skinny_metadata = 0;
6322
6323         ret = lookup_extent_backref(trans, extent_root, path, &iref,
6324                                     bytenr, num_bytes, parent,
6325                                     root_objectid, owner_objectid,
6326                                     owner_offset);
6327         if (ret == 0) {
6328                 extent_slot = path->slots[0];
6329                 while (extent_slot >= 0) {
6330                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6331                                               extent_slot);
6332                         if (key.objectid != bytenr)
6333                                 break;
6334                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6335                             key.offset == num_bytes) {
6336                                 found_extent = 1;
6337                                 break;
6338                         }
6339                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6340                             key.offset == owner_objectid) {
6341                                 found_extent = 1;
6342                                 break;
6343                         }
6344                         if (path->slots[0] - extent_slot > 5)
6345                                 break;
6346                         extent_slot--;
6347                 }
6348 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6349                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6350                 if (found_extent && item_size < sizeof(*ei))
6351                         found_extent = 0;
6352 #endif
6353                 if (!found_extent) {
6354                         BUG_ON(iref);
6355                         ret = remove_extent_backref(trans, extent_root, path,
6356                                                     NULL, refs_to_drop,
6357                                                     is_data, &last_ref);
6358                         if (ret) {
6359                                 btrfs_abort_transaction(trans, extent_root, ret);
6360                                 goto out;
6361                         }
6362                         btrfs_release_path(path);
6363                         path->leave_spinning = 1;
6364
6365                         key.objectid = bytenr;
6366                         key.type = BTRFS_EXTENT_ITEM_KEY;
6367                         key.offset = num_bytes;
6368
6369                         if (!is_data && skinny_metadata) {
6370                                 key.type = BTRFS_METADATA_ITEM_KEY;
6371                                 key.offset = owner_objectid;
6372                         }
6373
6374                         ret = btrfs_search_slot(trans, extent_root,
6375                                                 &key, path, -1, 1);
6376                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6377                                 /*
6378                                  * Couldn't find our skinny metadata item,
6379                                  * see if we have ye olde extent item.
6380                                  */
6381                                 path->slots[0]--;
6382                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6383                                                       path->slots[0]);
6384                                 if (key.objectid == bytenr &&
6385                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6386                                     key.offset == num_bytes)
6387                                         ret = 0;
6388                         }
6389
6390                         if (ret > 0 && skinny_metadata) {
6391                                 skinny_metadata = false;
6392                                 key.objectid = bytenr;
6393                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6394                                 key.offset = num_bytes;
6395                                 btrfs_release_path(path);
6396                                 ret = btrfs_search_slot(trans, extent_root,
6397                                                         &key, path, -1, 1);
6398                         }
6399
6400                         if (ret) {
6401                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6402                                         ret, bytenr);
6403                                 if (ret > 0)
6404                                         btrfs_print_leaf(extent_root,
6405                                                          path->nodes[0]);
6406                         }
6407                         if (ret < 0) {
6408                                 btrfs_abort_transaction(trans, extent_root, ret);
6409                                 goto out;
6410                         }
6411                         extent_slot = path->slots[0];
6412                 }
6413         } else if (WARN_ON(ret == -ENOENT)) {
6414                 btrfs_print_leaf(extent_root, path->nodes[0]);
6415                 btrfs_err(info,
6416                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6417                         bytenr, parent, root_objectid, owner_objectid,
6418                         owner_offset);
6419                 btrfs_abort_transaction(trans, extent_root, ret);
6420                 goto out;
6421         } else {
6422                 btrfs_abort_transaction(trans, extent_root, ret);
6423                 goto out;
6424         }
6425
6426         leaf = path->nodes[0];
6427         item_size = btrfs_item_size_nr(leaf, extent_slot);
6428 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6429         if (item_size < sizeof(*ei)) {
6430                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6431                 ret = convert_extent_item_v0(trans, extent_root, path,
6432                                              owner_objectid, 0);
6433                 if (ret < 0) {
6434                         btrfs_abort_transaction(trans, extent_root, ret);
6435                         goto out;
6436                 }
6437
6438                 btrfs_release_path(path);
6439                 path->leave_spinning = 1;
6440
6441                 key.objectid = bytenr;
6442                 key.type = BTRFS_EXTENT_ITEM_KEY;
6443                 key.offset = num_bytes;
6444
6445                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6446                                         -1, 1);
6447                 if (ret) {
6448                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6449                                 ret, bytenr);
6450                         btrfs_print_leaf(extent_root, path->nodes[0]);
6451                 }
6452                 if (ret < 0) {
6453                         btrfs_abort_transaction(trans, extent_root, ret);
6454                         goto out;
6455                 }
6456
6457                 extent_slot = path->slots[0];
6458                 leaf = path->nodes[0];
6459                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6460         }
6461 #endif
6462         BUG_ON(item_size < sizeof(*ei));
6463         ei = btrfs_item_ptr(leaf, extent_slot,
6464                             struct btrfs_extent_item);
6465         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6466             key.type == BTRFS_EXTENT_ITEM_KEY) {
6467                 struct btrfs_tree_block_info *bi;
6468                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6469                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6470                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6471         }
6472
6473         refs = btrfs_extent_refs(leaf, ei);
6474         if (refs < refs_to_drop) {
6475                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
6476                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
6477                 ret = -EINVAL;
6478                 btrfs_abort_transaction(trans, extent_root, ret);
6479                 goto out;
6480         }
6481         refs -= refs_to_drop;
6482
6483         if (refs > 0) {
6484                 if (extent_op)
6485                         __run_delayed_extent_op(extent_op, leaf, ei);
6486                 /*
6487                  * In the case of inline back ref, reference count will
6488                  * be updated by remove_extent_backref
6489                  */
6490                 if (iref) {
6491                         BUG_ON(!found_extent);
6492                 } else {
6493                         btrfs_set_extent_refs(leaf, ei, refs);
6494                         btrfs_mark_buffer_dirty(leaf);
6495                 }
6496                 if (found_extent) {
6497                         ret = remove_extent_backref(trans, extent_root, path,
6498                                                     iref, refs_to_drop,
6499                                                     is_data, &last_ref);
6500                         if (ret) {
6501                                 btrfs_abort_transaction(trans, extent_root, ret);
6502                                 goto out;
6503                         }
6504                 }
6505                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
6506                                  root_objectid);
6507         } else {
6508                 if (found_extent) {
6509                         BUG_ON(is_data && refs_to_drop !=
6510                                extent_data_ref_count(path, iref));
6511                         if (iref) {
6512                                 BUG_ON(path->slots[0] != extent_slot);
6513                         } else {
6514                                 BUG_ON(path->slots[0] != extent_slot + 1);
6515                                 path->slots[0] = extent_slot;
6516                                 num_to_del = 2;
6517                         }
6518                 }
6519
6520                 last_ref = 1;
6521                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6522                                       num_to_del);
6523                 if (ret) {
6524                         btrfs_abort_transaction(trans, extent_root, ret);
6525                         goto out;
6526                 }
6527                 btrfs_release_path(path);
6528
6529                 if (is_data) {
6530                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
6531                         if (ret) {
6532                                 btrfs_abort_transaction(trans, extent_root, ret);
6533                                 goto out;
6534                         }
6535                 }
6536
6537                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
6538                 if (ret) {
6539                         btrfs_abort_transaction(trans, extent_root, ret);
6540                         goto out;
6541                 }
6542         }
6543         btrfs_release_path(path);
6544
6545 out:
6546         btrfs_free_path(path);
6547         return ret;
6548 }
6549
6550 /*
6551  * when we free an block, it is possible (and likely) that we free the last
6552  * delayed ref for that extent as well.  This searches the delayed ref tree for
6553  * a given extent, and if there are no other delayed refs to be processed, it
6554  * removes it from the tree.
6555  */
6556 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6557                                       struct btrfs_root *root, u64 bytenr)
6558 {
6559         struct btrfs_delayed_ref_head *head;
6560         struct btrfs_delayed_ref_root *delayed_refs;
6561         int ret = 0;
6562
6563         delayed_refs = &trans->transaction->delayed_refs;
6564         spin_lock(&delayed_refs->lock);
6565         head = btrfs_find_delayed_ref_head(trans, bytenr);
6566         if (!head)
6567                 goto out_delayed_unlock;
6568
6569         spin_lock(&head->lock);
6570         if (!list_empty(&head->ref_list))
6571                 goto out;
6572
6573         if (head->extent_op) {
6574                 if (!head->must_insert_reserved)
6575                         goto out;
6576                 btrfs_free_delayed_extent_op(head->extent_op);
6577                 head->extent_op = NULL;
6578         }
6579
6580         /*
6581          * waiting for the lock here would deadlock.  If someone else has it
6582          * locked they are already in the process of dropping it anyway
6583          */
6584         if (!mutex_trylock(&head->mutex))
6585                 goto out;
6586
6587         /*
6588          * at this point we have a head with no other entries.  Go
6589          * ahead and process it.
6590          */
6591         head->node.in_tree = 0;
6592         rb_erase(&head->href_node, &delayed_refs->href_root);
6593
6594         atomic_dec(&delayed_refs->num_entries);
6595
6596         /*
6597          * we don't take a ref on the node because we're removing it from the
6598          * tree, so we just steal the ref the tree was holding.
6599          */
6600         delayed_refs->num_heads--;
6601         if (head->processing == 0)
6602                 delayed_refs->num_heads_ready--;
6603         head->processing = 0;
6604         spin_unlock(&head->lock);
6605         spin_unlock(&delayed_refs->lock);
6606
6607         BUG_ON(head->extent_op);
6608         if (head->must_insert_reserved)
6609                 ret = 1;
6610
6611         mutex_unlock(&head->mutex);
6612         btrfs_put_delayed_ref(&head->node);
6613         return ret;
6614 out:
6615         spin_unlock(&head->lock);
6616
6617 out_delayed_unlock:
6618         spin_unlock(&delayed_refs->lock);
6619         return 0;
6620 }
6621
6622 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6623                            struct btrfs_root *root,
6624                            struct extent_buffer *buf,
6625                            u64 parent, int last_ref)
6626 {
6627         int pin = 1;
6628         int ret;
6629
6630         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6631                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6632                                         buf->start, buf->len,
6633                                         parent, root->root_key.objectid,
6634                                         btrfs_header_level(buf),
6635                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
6636                 BUG_ON(ret); /* -ENOMEM */
6637         }
6638
6639         if (!last_ref)
6640                 return;
6641
6642         if (btrfs_header_generation(buf) == trans->transid) {
6643                 struct btrfs_block_group_cache *cache;
6644
6645                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6646                         ret = check_ref_cleanup(trans, root, buf->start);
6647                         if (!ret)
6648                                 goto out;
6649                 }
6650
6651                 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6652
6653                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6654                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6655                         btrfs_put_block_group(cache);
6656                         goto out;
6657                 }
6658
6659                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6660
6661                 btrfs_add_free_space(cache, buf->start, buf->len);
6662                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
6663                 btrfs_put_block_group(cache);
6664                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6665                 pin = 0;
6666         }
6667 out:
6668         if (pin)
6669                 add_pinned_bytes(root->fs_info, buf->len,
6670                                  btrfs_header_level(buf),
6671                                  root->root_key.objectid);
6672
6673         /*
6674          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6675          * anymore.
6676          */
6677         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6678 }
6679
6680 /* Can return -ENOMEM */
6681 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6682                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6683                       u64 owner, u64 offset, int no_quota)
6684 {
6685         int ret;
6686         struct btrfs_fs_info *fs_info = root->fs_info;
6687
6688         if (btrfs_test_is_dummy_root(root))
6689                 return 0;
6690
6691         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6692
6693         /*
6694          * tree log blocks never actually go into the extent allocation
6695          * tree, just update pinning info and exit early.
6696          */
6697         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6698                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6699                 /* unlocks the pinned mutex */
6700                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6701                 ret = 0;
6702         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6703                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6704                                         num_bytes,
6705                                         parent, root_objectid, (int)owner,
6706                                         BTRFS_DROP_DELAYED_REF, NULL, no_quota);
6707         } else {
6708                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6709                                                 num_bytes,
6710                                                 parent, root_objectid, owner,
6711                                                 offset, BTRFS_DROP_DELAYED_REF,
6712                                                 NULL, no_quota);
6713         }
6714         return ret;
6715 }
6716
6717 /*
6718  * when we wait for progress in the block group caching, its because
6719  * our allocation attempt failed at least once.  So, we must sleep
6720  * and let some progress happen before we try again.
6721  *
6722  * This function will sleep at least once waiting for new free space to
6723  * show up, and then it will check the block group free space numbers
6724  * for our min num_bytes.  Another option is to have it go ahead
6725  * and look in the rbtree for a free extent of a given size, but this
6726  * is a good start.
6727  *
6728  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6729  * any of the information in this block group.
6730  */
6731 static noinline void
6732 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6733                                 u64 num_bytes)
6734 {
6735         struct btrfs_caching_control *caching_ctl;
6736
6737         caching_ctl = get_caching_control(cache);
6738         if (!caching_ctl)
6739                 return;
6740
6741         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6742                    (cache->free_space_ctl->free_space >= num_bytes));
6743
6744         put_caching_control(caching_ctl);
6745 }
6746
6747 static noinline int
6748 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6749 {
6750         struct btrfs_caching_control *caching_ctl;
6751         int ret = 0;
6752
6753         caching_ctl = get_caching_control(cache);
6754         if (!caching_ctl)
6755                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6756
6757         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6758         if (cache->cached == BTRFS_CACHE_ERROR)
6759                 ret = -EIO;
6760         put_caching_control(caching_ctl);
6761         return ret;
6762 }
6763
6764 int __get_raid_index(u64 flags)
6765 {
6766         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6767                 return BTRFS_RAID_RAID10;
6768         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6769                 return BTRFS_RAID_RAID1;
6770         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6771                 return BTRFS_RAID_DUP;
6772         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6773                 return BTRFS_RAID_RAID0;
6774         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6775                 return BTRFS_RAID_RAID5;
6776         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6777                 return BTRFS_RAID_RAID6;
6778
6779         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6780 }
6781
6782 int get_block_group_index(struct btrfs_block_group_cache *cache)
6783 {
6784         return __get_raid_index(cache->flags);
6785 }
6786
6787 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6788         [BTRFS_RAID_RAID10]     = "raid10",
6789         [BTRFS_RAID_RAID1]      = "raid1",
6790         [BTRFS_RAID_DUP]        = "dup",
6791         [BTRFS_RAID_RAID0]      = "raid0",
6792         [BTRFS_RAID_SINGLE]     = "single",
6793         [BTRFS_RAID_RAID5]      = "raid5",
6794         [BTRFS_RAID_RAID6]      = "raid6",
6795 };
6796
6797 static const char *get_raid_name(enum btrfs_raid_types type)
6798 {
6799         if (type >= BTRFS_NR_RAID_TYPES)
6800                 return NULL;
6801
6802         return btrfs_raid_type_names[type];
6803 }
6804
6805 enum btrfs_loop_type {
6806         LOOP_CACHING_NOWAIT = 0,
6807         LOOP_CACHING_WAIT = 1,
6808         LOOP_ALLOC_CHUNK = 2,
6809         LOOP_NO_EMPTY_SIZE = 3,
6810 };
6811
6812 static inline void
6813 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
6814                        int delalloc)
6815 {
6816         if (delalloc)
6817                 down_read(&cache->data_rwsem);
6818 }
6819
6820 static inline void
6821 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
6822                        int delalloc)
6823 {
6824         btrfs_get_block_group(cache);
6825         if (delalloc)
6826                 down_read(&cache->data_rwsem);
6827 }
6828
6829 static struct btrfs_block_group_cache *
6830 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
6831                    struct btrfs_free_cluster *cluster,
6832                    int delalloc)
6833 {
6834         struct btrfs_block_group_cache *used_bg;
6835         bool locked = false;
6836 again:
6837         spin_lock(&cluster->refill_lock);
6838         if (locked) {
6839                 if (used_bg == cluster->block_group)
6840                         return used_bg;
6841
6842                 up_read(&used_bg->data_rwsem);
6843                 btrfs_put_block_group(used_bg);
6844         }
6845
6846         used_bg = cluster->block_group;
6847         if (!used_bg)
6848                 return NULL;
6849
6850         if (used_bg == block_group)
6851                 return used_bg;
6852
6853         btrfs_get_block_group(used_bg);
6854
6855         if (!delalloc)
6856                 return used_bg;
6857
6858         if (down_read_trylock(&used_bg->data_rwsem))
6859                 return used_bg;
6860
6861         spin_unlock(&cluster->refill_lock);
6862         down_read(&used_bg->data_rwsem);
6863         locked = true;
6864         goto again;
6865 }
6866
6867 static inline void
6868 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
6869                          int delalloc)
6870 {
6871         if (delalloc)
6872                 up_read(&cache->data_rwsem);
6873         btrfs_put_block_group(cache);
6874 }
6875
6876 /*
6877  * walks the btree of allocated extents and find a hole of a given size.
6878  * The key ins is changed to record the hole:
6879  * ins->objectid == start position
6880  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6881  * ins->offset == the size of the hole.
6882  * Any available blocks before search_start are skipped.
6883  *
6884  * If there is no suitable free space, we will record the max size of
6885  * the free space extent currently.
6886  */
6887 static noinline int find_free_extent(struct btrfs_root *orig_root,
6888                                      u64 num_bytes, u64 empty_size,
6889                                      u64 hint_byte, struct btrfs_key *ins,
6890                                      u64 flags, int delalloc)
6891 {
6892         int ret = 0;
6893         struct btrfs_root *root = orig_root->fs_info->extent_root;
6894         struct btrfs_free_cluster *last_ptr = NULL;
6895         struct btrfs_block_group_cache *block_group = NULL;
6896         u64 search_start = 0;
6897         u64 max_extent_size = 0;
6898         int empty_cluster = 2 * 1024 * 1024;
6899         struct btrfs_space_info *space_info;
6900         int loop = 0;
6901         int index = __get_raid_index(flags);
6902         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6903                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6904         bool failed_cluster_refill = false;
6905         bool failed_alloc = false;
6906         bool use_cluster = true;
6907         bool have_caching_bg = false;
6908
6909         WARN_ON(num_bytes < root->sectorsize);
6910         ins->type = BTRFS_EXTENT_ITEM_KEY;
6911         ins->objectid = 0;
6912         ins->offset = 0;
6913
6914         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6915
6916         space_info = __find_space_info(root->fs_info, flags);
6917         if (!space_info) {
6918                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6919                 return -ENOSPC;
6920         }
6921
6922         /*
6923          * If the space info is for both data and metadata it means we have a
6924          * small filesystem and we can't use the clustering stuff.
6925          */
6926         if (btrfs_mixed_space_info(space_info))
6927                 use_cluster = false;
6928
6929         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6930                 last_ptr = &root->fs_info->meta_alloc_cluster;
6931                 if (!btrfs_test_opt(root, SSD))
6932                         empty_cluster = 64 * 1024;
6933         }
6934
6935         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6936             btrfs_test_opt(root, SSD)) {
6937                 last_ptr = &root->fs_info->data_alloc_cluster;
6938         }
6939
6940         if (last_ptr) {
6941                 spin_lock(&last_ptr->lock);
6942                 if (last_ptr->block_group)
6943                         hint_byte = last_ptr->window_start;
6944                 spin_unlock(&last_ptr->lock);
6945         }
6946
6947         search_start = max(search_start, first_logical_byte(root, 0));
6948         search_start = max(search_start, hint_byte);
6949
6950         if (!last_ptr)
6951                 empty_cluster = 0;
6952
6953         if (search_start == hint_byte) {
6954                 block_group = btrfs_lookup_block_group(root->fs_info,
6955                                                        search_start);
6956                 /*
6957                  * we don't want to use the block group if it doesn't match our
6958                  * allocation bits, or if its not cached.
6959                  *
6960                  * However if we are re-searching with an ideal block group
6961                  * picked out then we don't care that the block group is cached.
6962                  */
6963                 if (block_group && block_group_bits(block_group, flags) &&
6964                     block_group->cached != BTRFS_CACHE_NO) {
6965                         down_read(&space_info->groups_sem);
6966                         if (list_empty(&block_group->list) ||
6967                             block_group->ro) {
6968                                 /*
6969                                  * someone is removing this block group,
6970                                  * we can't jump into the have_block_group
6971                                  * target because our list pointers are not
6972                                  * valid
6973                                  */
6974                                 btrfs_put_block_group(block_group);
6975                                 up_read(&space_info->groups_sem);
6976                         } else {
6977                                 index = get_block_group_index(block_group);
6978                                 btrfs_lock_block_group(block_group, delalloc);
6979                                 goto have_block_group;
6980                         }
6981                 } else if (block_group) {
6982                         btrfs_put_block_group(block_group);
6983                 }
6984         }
6985 search:
6986         have_caching_bg = false;
6987         down_read(&space_info->groups_sem);
6988         list_for_each_entry(block_group, &space_info->block_groups[index],
6989                             list) {
6990                 u64 offset;
6991                 int cached;
6992
6993                 btrfs_grab_block_group(block_group, delalloc);
6994                 search_start = block_group->key.objectid;
6995
6996                 /*
6997                  * this can happen if we end up cycling through all the
6998                  * raid types, but we want to make sure we only allocate
6999                  * for the proper type.
7000                  */
7001                 if (!block_group_bits(block_group, flags)) {
7002                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7003                                 BTRFS_BLOCK_GROUP_RAID1 |
7004                                 BTRFS_BLOCK_GROUP_RAID5 |
7005                                 BTRFS_BLOCK_GROUP_RAID6 |
7006                                 BTRFS_BLOCK_GROUP_RAID10;
7007
7008                         /*
7009                          * if they asked for extra copies and this block group
7010                          * doesn't provide them, bail.  This does allow us to
7011                          * fill raid0 from raid1.
7012                          */
7013                         if ((flags & extra) && !(block_group->flags & extra))
7014                                 goto loop;
7015                 }
7016
7017 have_block_group:
7018                 cached = block_group_cache_done(block_group);
7019                 if (unlikely(!cached)) {
7020                         ret = cache_block_group(block_group, 0);
7021                         BUG_ON(ret < 0);
7022                         ret = 0;
7023                 }
7024
7025                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7026                         goto loop;
7027                 if (unlikely(block_group->ro))
7028                         goto loop;
7029
7030                 /*
7031                  * Ok we want to try and use the cluster allocator, so
7032                  * lets look there
7033                  */
7034                 if (last_ptr) {
7035                         struct btrfs_block_group_cache *used_block_group;
7036                         unsigned long aligned_cluster;
7037                         /*
7038                          * the refill lock keeps out other
7039                          * people trying to start a new cluster
7040                          */
7041                         used_block_group = btrfs_lock_cluster(block_group,
7042                                                               last_ptr,
7043                                                               delalloc);
7044                         if (!used_block_group)
7045                                 goto refill_cluster;
7046
7047                         if (used_block_group != block_group &&
7048                             (used_block_group->ro ||
7049                              !block_group_bits(used_block_group, flags)))
7050                                 goto release_cluster;
7051
7052                         offset = btrfs_alloc_from_cluster(used_block_group,
7053                                                 last_ptr,
7054                                                 num_bytes,
7055                                                 used_block_group->key.objectid,
7056                                                 &max_extent_size);
7057                         if (offset) {
7058                                 /* we have a block, we're done */
7059                                 spin_unlock(&last_ptr->refill_lock);
7060                                 trace_btrfs_reserve_extent_cluster(root,
7061                                                 used_block_group,
7062                                                 search_start, num_bytes);
7063                                 if (used_block_group != block_group) {
7064                                         btrfs_release_block_group(block_group,
7065                                                                   delalloc);
7066                                         block_group = used_block_group;
7067                                 }
7068                                 goto checks;
7069                         }
7070
7071                         WARN_ON(last_ptr->block_group != used_block_group);
7072 release_cluster:
7073                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7074                          * set up a new clusters, so lets just skip it
7075                          * and let the allocator find whatever block
7076                          * it can find.  If we reach this point, we
7077                          * will have tried the cluster allocator
7078                          * plenty of times and not have found
7079                          * anything, so we are likely way too
7080                          * fragmented for the clustering stuff to find
7081                          * anything.
7082                          *
7083                          * However, if the cluster is taken from the
7084                          * current block group, release the cluster
7085                          * first, so that we stand a better chance of
7086                          * succeeding in the unclustered
7087                          * allocation.  */
7088                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7089                             used_block_group != block_group) {
7090                                 spin_unlock(&last_ptr->refill_lock);
7091                                 btrfs_release_block_group(used_block_group,
7092                                                           delalloc);
7093                                 goto unclustered_alloc;
7094                         }
7095
7096                         /*
7097                          * this cluster didn't work out, free it and
7098                          * start over
7099                          */
7100                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7101
7102                         if (used_block_group != block_group)
7103                                 btrfs_release_block_group(used_block_group,
7104                                                           delalloc);
7105 refill_cluster:
7106                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7107                                 spin_unlock(&last_ptr->refill_lock);
7108                                 goto unclustered_alloc;
7109                         }
7110
7111                         aligned_cluster = max_t(unsigned long,
7112                                                 empty_cluster + empty_size,
7113                                               block_group->full_stripe_len);
7114
7115                         /* allocate a cluster in this block group */
7116                         ret = btrfs_find_space_cluster(root, block_group,
7117                                                        last_ptr, search_start,
7118                                                        num_bytes,
7119                                                        aligned_cluster);
7120                         if (ret == 0) {
7121                                 /*
7122                                  * now pull our allocation out of this
7123                                  * cluster
7124                                  */
7125                                 offset = btrfs_alloc_from_cluster(block_group,
7126                                                         last_ptr,
7127                                                         num_bytes,
7128                                                         search_start,
7129                                                         &max_extent_size);
7130                                 if (offset) {
7131                                         /* we found one, proceed */
7132                                         spin_unlock(&last_ptr->refill_lock);
7133                                         trace_btrfs_reserve_extent_cluster(root,
7134                                                 block_group, search_start,
7135                                                 num_bytes);
7136                                         goto checks;
7137                                 }
7138                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7139                                    && !failed_cluster_refill) {
7140                                 spin_unlock(&last_ptr->refill_lock);
7141
7142                                 failed_cluster_refill = true;
7143                                 wait_block_group_cache_progress(block_group,
7144                                        num_bytes + empty_cluster + empty_size);
7145                                 goto have_block_group;
7146                         }
7147
7148                         /*
7149                          * at this point we either didn't find a cluster
7150                          * or we weren't able to allocate a block from our
7151                          * cluster.  Free the cluster we've been trying
7152                          * to use, and go to the next block group
7153                          */
7154                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7155                         spin_unlock(&last_ptr->refill_lock);
7156                         goto loop;
7157                 }
7158
7159 unclustered_alloc:
7160                 spin_lock(&block_group->free_space_ctl->tree_lock);
7161                 if (cached &&
7162                     block_group->free_space_ctl->free_space <
7163                     num_bytes + empty_cluster + empty_size) {
7164                         if (block_group->free_space_ctl->free_space >
7165                             max_extent_size)
7166                                 max_extent_size =
7167                                         block_group->free_space_ctl->free_space;
7168                         spin_unlock(&block_group->free_space_ctl->tree_lock);
7169                         goto loop;
7170                 }
7171                 spin_unlock(&block_group->free_space_ctl->tree_lock);
7172
7173                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7174                                                     num_bytes, empty_size,
7175                                                     &max_extent_size);
7176                 /*
7177                  * If we didn't find a chunk, and we haven't failed on this
7178                  * block group before, and this block group is in the middle of
7179                  * caching and we are ok with waiting, then go ahead and wait
7180                  * for progress to be made, and set failed_alloc to true.
7181                  *
7182                  * If failed_alloc is true then we've already waited on this
7183                  * block group once and should move on to the next block group.
7184                  */
7185                 if (!offset && !failed_alloc && !cached &&
7186                     loop > LOOP_CACHING_NOWAIT) {
7187                         wait_block_group_cache_progress(block_group,
7188                                                 num_bytes + empty_size);
7189                         failed_alloc = true;
7190                         goto have_block_group;
7191                 } else if (!offset) {
7192                         if (!cached)
7193                                 have_caching_bg = true;
7194                         goto loop;
7195                 }
7196 checks:
7197                 search_start = ALIGN(offset, root->stripesize);
7198
7199                 /* move on to the next group */
7200                 if (search_start + num_bytes >
7201                     block_group->key.objectid + block_group->key.offset) {
7202                         btrfs_add_free_space(block_group, offset, num_bytes);
7203                         goto loop;
7204                 }
7205
7206                 if (offset < search_start)
7207                         btrfs_add_free_space(block_group, offset,
7208                                              search_start - offset);
7209                 BUG_ON(offset > search_start);
7210
7211                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
7212                                                   alloc_type, delalloc);
7213                 if (ret == -EAGAIN) {
7214                         btrfs_add_free_space(block_group, offset, num_bytes);
7215                         goto loop;
7216                 }
7217
7218                 /* we are all good, lets return */
7219                 ins->objectid = search_start;
7220                 ins->offset = num_bytes;
7221
7222                 trace_btrfs_reserve_extent(orig_root, block_group,
7223                                            search_start, num_bytes);
7224                 btrfs_release_block_group(block_group, delalloc);
7225                 break;
7226 loop:
7227                 failed_cluster_refill = false;
7228                 failed_alloc = false;
7229                 BUG_ON(index != get_block_group_index(block_group));
7230                 btrfs_release_block_group(block_group, delalloc);
7231         }
7232         up_read(&space_info->groups_sem);
7233
7234         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7235                 goto search;
7236
7237         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7238                 goto search;
7239
7240         /*
7241          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7242          *                      caching kthreads as we move along
7243          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7244          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7245          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7246          *                      again
7247          */
7248         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7249                 index = 0;
7250                 loop++;
7251                 if (loop == LOOP_ALLOC_CHUNK) {
7252                         struct btrfs_trans_handle *trans;
7253                         int exist = 0;
7254
7255                         trans = current->journal_info;
7256                         if (trans)
7257                                 exist = 1;
7258                         else
7259                                 trans = btrfs_join_transaction(root);
7260
7261                         if (IS_ERR(trans)) {
7262                                 ret = PTR_ERR(trans);
7263                                 goto out;
7264                         }
7265
7266                         ret = do_chunk_alloc(trans, root, flags,
7267                                              CHUNK_ALLOC_FORCE);
7268                         /*
7269                          * Do not bail out on ENOSPC since we
7270                          * can do more things.
7271                          */
7272                         if (ret < 0 && ret != -ENOSPC)
7273                                 btrfs_abort_transaction(trans,
7274                                                         root, ret);
7275                         else
7276                                 ret = 0;
7277                         if (!exist)
7278                                 btrfs_end_transaction(trans, root);
7279                         if (ret)
7280                                 goto out;
7281                 }
7282
7283                 if (loop == LOOP_NO_EMPTY_SIZE) {
7284                         empty_size = 0;
7285                         empty_cluster = 0;
7286                 }
7287
7288                 goto search;
7289         } else if (!ins->objectid) {
7290                 ret = -ENOSPC;
7291         } else if (ins->objectid) {
7292                 ret = 0;
7293         }
7294 out:
7295         if (ret == -ENOSPC)
7296                 ins->offset = max_extent_size;
7297         return ret;
7298 }
7299
7300 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7301                             int dump_block_groups)
7302 {
7303         struct btrfs_block_group_cache *cache;
7304         int index = 0;
7305
7306         spin_lock(&info->lock);
7307         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7308                info->flags,
7309                info->total_bytes - info->bytes_used - info->bytes_pinned -
7310                info->bytes_reserved - info->bytes_readonly,
7311                (info->full) ? "" : "not ");
7312         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7313                "reserved=%llu, may_use=%llu, readonly=%llu\n",
7314                info->total_bytes, info->bytes_used, info->bytes_pinned,
7315                info->bytes_reserved, info->bytes_may_use,
7316                info->bytes_readonly);
7317         spin_unlock(&info->lock);
7318
7319         if (!dump_block_groups)
7320                 return;
7321
7322         down_read(&info->groups_sem);
7323 again:
7324         list_for_each_entry(cache, &info->block_groups[index], list) {
7325                 spin_lock(&cache->lock);
7326                 printk(KERN_INFO "BTRFS: "
7327                            "block group %llu has %llu bytes, "
7328                            "%llu used %llu pinned %llu reserved %s\n",
7329                        cache->key.objectid, cache->key.offset,
7330                        btrfs_block_group_used(&cache->item), cache->pinned,
7331                        cache->reserved, cache->ro ? "[readonly]" : "");
7332                 btrfs_dump_free_space(cache, bytes);
7333                 spin_unlock(&cache->lock);
7334         }
7335         if (++index < BTRFS_NR_RAID_TYPES)
7336                 goto again;
7337         up_read(&info->groups_sem);
7338 }
7339
7340 int btrfs_reserve_extent(struct btrfs_root *root,
7341                          u64 num_bytes, u64 min_alloc_size,
7342                          u64 empty_size, u64 hint_byte,
7343                          struct btrfs_key *ins, int is_data, int delalloc)
7344 {
7345         bool final_tried = false;
7346         u64 flags;
7347         int ret;
7348
7349         flags = btrfs_get_alloc_profile(root, is_data);
7350 again:
7351         WARN_ON(num_bytes < root->sectorsize);
7352         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
7353                                flags, delalloc);
7354
7355         if (ret == -ENOSPC) {
7356                 if (!final_tried && ins->offset) {
7357                         num_bytes = min(num_bytes >> 1, ins->offset);
7358                         num_bytes = round_down(num_bytes, root->sectorsize);
7359                         num_bytes = max(num_bytes, min_alloc_size);
7360                         if (num_bytes == min_alloc_size)
7361                                 final_tried = true;
7362                         goto again;
7363                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7364                         struct btrfs_space_info *sinfo;
7365
7366                         sinfo = __find_space_info(root->fs_info, flags);
7367                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7368                                 flags, num_bytes);
7369                         if (sinfo)
7370                                 dump_space_info(sinfo, num_bytes, 1);
7371                 }
7372         }
7373
7374         return ret;
7375 }
7376
7377 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7378                                         u64 start, u64 len,
7379                                         int pin, int delalloc)
7380 {
7381         struct btrfs_block_group_cache *cache;
7382         int ret = 0;
7383
7384         cache = btrfs_lookup_block_group(root->fs_info, start);
7385         if (!cache) {
7386                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7387                         start);
7388                 return -ENOSPC;
7389         }
7390
7391         if (pin)
7392                 pin_down_extent(root, cache, start, len, 1);
7393         else {
7394                 if (btrfs_test_opt(root, DISCARD))
7395                         ret = btrfs_discard_extent(root, start, len, NULL);
7396                 btrfs_add_free_space(cache, start, len);
7397                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
7398         }
7399
7400         btrfs_put_block_group(cache);
7401
7402         trace_btrfs_reserved_extent_free(root, start, len);
7403
7404         return ret;
7405 }
7406
7407 int btrfs_free_reserved_extent(struct btrfs_root *root,
7408                                u64 start, u64 len, int delalloc)
7409 {
7410         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
7411 }
7412
7413 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
7414                                        u64 start, u64 len)
7415 {
7416         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
7417 }
7418
7419 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7420                                       struct btrfs_root *root,
7421                                       u64 parent, u64 root_objectid,
7422                                       u64 flags, u64 owner, u64 offset,
7423                                       struct btrfs_key *ins, int ref_mod)
7424 {
7425         int ret;
7426         struct btrfs_fs_info *fs_info = root->fs_info;
7427         struct btrfs_extent_item *extent_item;
7428         struct btrfs_extent_inline_ref *iref;
7429         struct btrfs_path *path;
7430         struct extent_buffer *leaf;
7431         int type;
7432         u32 size;
7433
7434         if (parent > 0)
7435                 type = BTRFS_SHARED_DATA_REF_KEY;
7436         else
7437                 type = BTRFS_EXTENT_DATA_REF_KEY;
7438
7439         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7440
7441         path = btrfs_alloc_path();
7442         if (!path)
7443                 return -ENOMEM;
7444
7445         path->leave_spinning = 1;
7446         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7447                                       ins, size);
7448         if (ret) {
7449                 btrfs_free_path(path);
7450                 return ret;
7451         }
7452
7453         leaf = path->nodes[0];
7454         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7455                                      struct btrfs_extent_item);
7456         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7457         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7458         btrfs_set_extent_flags(leaf, extent_item,
7459                                flags | BTRFS_EXTENT_FLAG_DATA);
7460
7461         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7462         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7463         if (parent > 0) {
7464                 struct btrfs_shared_data_ref *ref;
7465                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7466                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7467                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7468         } else {
7469                 struct btrfs_extent_data_ref *ref;
7470                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7471                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7472                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7473                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7474                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7475         }
7476
7477         btrfs_mark_buffer_dirty(path->nodes[0]);
7478         btrfs_free_path(path);
7479
7480         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
7481         if (ret) { /* -ENOENT, logic error */
7482                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7483                         ins->objectid, ins->offset);
7484                 BUG();
7485         }
7486         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
7487         return ret;
7488 }
7489
7490 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7491                                      struct btrfs_root *root,
7492                                      u64 parent, u64 root_objectid,
7493                                      u64 flags, struct btrfs_disk_key *key,
7494                                      int level, struct btrfs_key *ins,
7495                                      int no_quota)
7496 {
7497         int ret;
7498         struct btrfs_fs_info *fs_info = root->fs_info;
7499         struct btrfs_extent_item *extent_item;
7500         struct btrfs_tree_block_info *block_info;
7501         struct btrfs_extent_inline_ref *iref;
7502         struct btrfs_path *path;
7503         struct extent_buffer *leaf;
7504         u32 size = sizeof(*extent_item) + sizeof(*iref);
7505         u64 num_bytes = ins->offset;
7506         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7507                                                  SKINNY_METADATA);
7508
7509         if (!skinny_metadata)
7510                 size += sizeof(*block_info);
7511
7512         path = btrfs_alloc_path();
7513         if (!path) {
7514                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7515                                                    root->nodesize);
7516                 return -ENOMEM;
7517         }
7518
7519         path->leave_spinning = 1;
7520         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7521                                       ins, size);
7522         if (ret) {
7523                 btrfs_free_path(path);
7524                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7525                                                    root->nodesize);
7526                 return ret;
7527         }
7528
7529         leaf = path->nodes[0];
7530         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7531                                      struct btrfs_extent_item);
7532         btrfs_set_extent_refs(leaf, extent_item, 1);
7533         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7534         btrfs_set_extent_flags(leaf, extent_item,
7535                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
7536
7537         if (skinny_metadata) {
7538                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7539                 num_bytes = root->nodesize;
7540         } else {
7541                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
7542                 btrfs_set_tree_block_key(leaf, block_info, key);
7543                 btrfs_set_tree_block_level(leaf, block_info, level);
7544                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
7545         }
7546
7547         if (parent > 0) {
7548                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
7549                 btrfs_set_extent_inline_ref_type(leaf, iref,
7550                                                  BTRFS_SHARED_BLOCK_REF_KEY);
7551                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7552         } else {
7553                 btrfs_set_extent_inline_ref_type(leaf, iref,
7554                                                  BTRFS_TREE_BLOCK_REF_KEY);
7555                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
7556         }
7557
7558         btrfs_mark_buffer_dirty(leaf);
7559         btrfs_free_path(path);
7560
7561         ret = update_block_group(trans, root, ins->objectid, root->nodesize,
7562                                  1);
7563         if (ret) { /* -ENOENT, logic error */
7564                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7565                         ins->objectid, ins->offset);
7566                 BUG();
7567         }
7568
7569         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
7570         return ret;
7571 }
7572
7573 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7574                                      struct btrfs_root *root,
7575                                      u64 root_objectid, u64 owner,
7576                                      u64 offset, struct btrfs_key *ins)
7577 {
7578         int ret;
7579
7580         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
7581
7582         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
7583                                          ins->offset, 0,
7584                                          root_objectid, owner, offset,
7585                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
7586         return ret;
7587 }
7588
7589 /*
7590  * this is used by the tree logging recovery code.  It records that
7591  * an extent has been allocated and makes sure to clear the free
7592  * space cache bits as well
7593  */
7594 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
7595                                    struct btrfs_root *root,
7596                                    u64 root_objectid, u64 owner, u64 offset,
7597                                    struct btrfs_key *ins)
7598 {
7599         int ret;
7600         struct btrfs_block_group_cache *block_group;
7601
7602         /*
7603          * Mixed block groups will exclude before processing the log so we only
7604          * need to do the exlude dance if this fs isn't mixed.
7605          */
7606         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
7607                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
7608                 if (ret)
7609                         return ret;
7610         }
7611
7612         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
7613         if (!block_group)
7614                 return -EINVAL;
7615
7616         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
7617                                           RESERVE_ALLOC_NO_ACCOUNT, 0);
7618         BUG_ON(ret); /* logic error */
7619         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
7620                                          0, owner, offset, ins, 1);
7621         btrfs_put_block_group(block_group);
7622         return ret;
7623 }
7624
7625 static struct extent_buffer *
7626 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7627                       u64 bytenr, int level)
7628 {
7629         struct extent_buffer *buf;
7630
7631         buf = btrfs_find_create_tree_block(root, bytenr);
7632         if (!buf)
7633                 return ERR_PTR(-ENOMEM);
7634         btrfs_set_header_generation(buf, trans->transid);
7635         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
7636         btrfs_tree_lock(buf);
7637         clean_tree_block(trans, root->fs_info, buf);
7638         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
7639
7640         btrfs_set_lock_blocking(buf);
7641         btrfs_set_buffer_uptodate(buf);
7642
7643         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
7644                 buf->log_index = root->log_transid % 2;
7645                 /*
7646                  * we allow two log transactions at a time, use different
7647                  * EXENT bit to differentiate dirty pages.
7648                  */
7649                 if (buf->log_index == 0)
7650                         set_extent_dirty(&root->dirty_log_pages, buf->start,
7651                                         buf->start + buf->len - 1, GFP_NOFS);
7652                 else
7653                         set_extent_new(&root->dirty_log_pages, buf->start,
7654                                         buf->start + buf->len - 1, GFP_NOFS);
7655         } else {
7656                 buf->log_index = -1;
7657                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
7658                          buf->start + buf->len - 1, GFP_NOFS);
7659         }
7660         trans->blocks_used++;
7661         /* this returns a buffer locked for blocking */
7662         return buf;
7663 }
7664
7665 static struct btrfs_block_rsv *
7666 use_block_rsv(struct btrfs_trans_handle *trans,
7667               struct btrfs_root *root, u32 blocksize)
7668 {
7669         struct btrfs_block_rsv *block_rsv;
7670         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
7671         int ret;
7672         bool global_updated = false;
7673
7674         block_rsv = get_block_rsv(trans, root);
7675
7676         if (unlikely(block_rsv->size == 0))
7677                 goto try_reserve;
7678 again:
7679         ret = block_rsv_use_bytes(block_rsv, blocksize);
7680         if (!ret)
7681                 return block_rsv;
7682
7683         if (block_rsv->failfast)
7684                 return ERR_PTR(ret);
7685
7686         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
7687                 global_updated = true;
7688                 update_global_block_rsv(root->fs_info);
7689                 goto again;
7690         }
7691
7692         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7693                 static DEFINE_RATELIMIT_STATE(_rs,
7694                                 DEFAULT_RATELIMIT_INTERVAL * 10,
7695                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
7696                 if (__ratelimit(&_rs))
7697                         WARN(1, KERN_DEBUG
7698                                 "BTRFS: block rsv returned %d\n", ret);
7699         }
7700 try_reserve:
7701         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
7702                                      BTRFS_RESERVE_NO_FLUSH);
7703         if (!ret)
7704                 return block_rsv;
7705         /*
7706          * If we couldn't reserve metadata bytes try and use some from
7707          * the global reserve if its space type is the same as the global
7708          * reservation.
7709          */
7710         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
7711             block_rsv->space_info == global_rsv->space_info) {
7712                 ret = block_rsv_use_bytes(global_rsv, blocksize);
7713                 if (!ret)
7714                         return global_rsv;
7715         }
7716         return ERR_PTR(ret);
7717 }
7718
7719 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
7720                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
7721 {
7722         block_rsv_add_bytes(block_rsv, blocksize, 0);
7723         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
7724 }
7725
7726 /*
7727  * finds a free extent and does all the dirty work required for allocation
7728  * returns the tree buffer or an ERR_PTR on error.
7729  */
7730 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
7731                                         struct btrfs_root *root,
7732                                         u64 parent, u64 root_objectid,
7733                                         struct btrfs_disk_key *key, int level,
7734                                         u64 hint, u64 empty_size)
7735 {
7736         struct btrfs_key ins;
7737         struct btrfs_block_rsv *block_rsv;
7738         struct extent_buffer *buf;
7739         struct btrfs_delayed_extent_op *extent_op;
7740         u64 flags = 0;
7741         int ret;
7742         u32 blocksize = root->nodesize;
7743         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7744                                                  SKINNY_METADATA);
7745
7746         if (btrfs_test_is_dummy_root(root)) {
7747                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
7748                                             level);
7749                 if (!IS_ERR(buf))
7750                         root->alloc_bytenr += blocksize;
7751                 return buf;
7752         }
7753
7754         block_rsv = use_block_rsv(trans, root, blocksize);
7755         if (IS_ERR(block_rsv))
7756                 return ERR_CAST(block_rsv);
7757
7758         ret = btrfs_reserve_extent(root, blocksize, blocksize,
7759                                    empty_size, hint, &ins, 0, 0);
7760         if (ret)
7761                 goto out_unuse;
7762
7763         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
7764         if (IS_ERR(buf)) {
7765                 ret = PTR_ERR(buf);
7766                 goto out_free_reserved;
7767         }
7768
7769         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
7770                 if (parent == 0)
7771                         parent = ins.objectid;
7772                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
7773         } else
7774                 BUG_ON(parent > 0);
7775
7776         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
7777                 extent_op = btrfs_alloc_delayed_extent_op();
7778                 if (!extent_op) {
7779                         ret = -ENOMEM;
7780                         goto out_free_buf;
7781                 }
7782                 if (key)
7783                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
7784                 else
7785                         memset(&extent_op->key, 0, sizeof(extent_op->key));
7786                 extent_op->flags_to_set = flags;
7787                 if (skinny_metadata)
7788                         extent_op->update_key = 0;
7789                 else
7790                         extent_op->update_key = 1;
7791                 extent_op->update_flags = 1;
7792                 extent_op->is_data = 0;
7793                 extent_op->level = level;
7794
7795                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7796                                                  ins.objectid, ins.offset,
7797                                                  parent, root_objectid, level,
7798                                                  BTRFS_ADD_DELAYED_EXTENT,
7799                                                  extent_op, 0);
7800                 if (ret)
7801                         goto out_free_delayed;
7802         }
7803         return buf;
7804
7805 out_free_delayed:
7806         btrfs_free_delayed_extent_op(extent_op);
7807 out_free_buf:
7808         free_extent_buffer(buf);
7809 out_free_reserved:
7810         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
7811 out_unuse:
7812         unuse_block_rsv(root->fs_info, block_rsv, blocksize);
7813         return ERR_PTR(ret);
7814 }
7815
7816 struct walk_control {
7817         u64 refs[BTRFS_MAX_LEVEL];
7818         u64 flags[BTRFS_MAX_LEVEL];
7819         struct btrfs_key update_progress;
7820         int stage;
7821         int level;
7822         int shared_level;
7823         int update_ref;
7824         int keep_locks;
7825         int reada_slot;
7826         int reada_count;
7827         int for_reloc;
7828 };
7829
7830 #define DROP_REFERENCE  1
7831 #define UPDATE_BACKREF  2
7832
7833 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7834                                      struct btrfs_root *root,
7835                                      struct walk_control *wc,
7836                                      struct btrfs_path *path)
7837 {
7838         u64 bytenr;
7839         u64 generation;
7840         u64 refs;
7841         u64 flags;
7842         u32 nritems;
7843         u32 blocksize;
7844         struct btrfs_key key;
7845         struct extent_buffer *eb;
7846         int ret;
7847         int slot;
7848         int nread = 0;
7849
7850         if (path->slots[wc->level] < wc->reada_slot) {
7851                 wc->reada_count = wc->reada_count * 2 / 3;
7852                 wc->reada_count = max(wc->reada_count, 2);
7853         } else {
7854                 wc->reada_count = wc->reada_count * 3 / 2;
7855                 wc->reada_count = min_t(int, wc->reada_count,
7856                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7857         }
7858
7859         eb = path->nodes[wc->level];
7860         nritems = btrfs_header_nritems(eb);
7861         blocksize = root->nodesize;
7862
7863         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7864                 if (nread >= wc->reada_count)
7865                         break;
7866
7867                 cond_resched();
7868                 bytenr = btrfs_node_blockptr(eb, slot);
7869                 generation = btrfs_node_ptr_generation(eb, slot);
7870
7871                 if (slot == path->slots[wc->level])
7872                         goto reada;
7873
7874                 if (wc->stage == UPDATE_BACKREF &&
7875                     generation <= root->root_key.offset)
7876                         continue;
7877
7878                 /* We don't lock the tree block, it's OK to be racy here */
7879                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7880                                                wc->level - 1, 1, &refs,
7881                                                &flags);
7882                 /* We don't care about errors in readahead. */
7883                 if (ret < 0)
7884                         continue;
7885                 BUG_ON(refs == 0);
7886
7887                 if (wc->stage == DROP_REFERENCE) {
7888                         if (refs == 1)
7889                                 goto reada;
7890
7891                         if (wc->level == 1 &&
7892                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7893                                 continue;
7894                         if (!wc->update_ref ||
7895                             generation <= root->root_key.offset)
7896                                 continue;
7897                         btrfs_node_key_to_cpu(eb, &key, slot);
7898                         ret = btrfs_comp_cpu_keys(&key,
7899                                                   &wc->update_progress);
7900                         if (ret < 0)
7901                                 continue;
7902                 } else {
7903                         if (wc->level == 1 &&
7904                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7905                                 continue;
7906                 }
7907 reada:
7908                 readahead_tree_block(root, bytenr);
7909                 nread++;
7910         }
7911         wc->reada_slot = slot;
7912 }
7913
7914 /*
7915  * TODO: Modify related function to add related node/leaf to dirty_extent_root,
7916  * for later qgroup accounting.
7917  *
7918  * Current, this function does nothing.
7919  */
7920 static int account_leaf_items(struct btrfs_trans_handle *trans,
7921                               struct btrfs_root *root,
7922                               struct extent_buffer *eb)
7923 {
7924         int nr = btrfs_header_nritems(eb);
7925         int i, extent_type;
7926         struct btrfs_key key;
7927         struct btrfs_file_extent_item *fi;
7928         u64 bytenr, num_bytes;
7929
7930         for (i = 0; i < nr; i++) {
7931                 btrfs_item_key_to_cpu(eb, &key, i);
7932
7933                 if (key.type != BTRFS_EXTENT_DATA_KEY)
7934                         continue;
7935
7936                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
7937                 /* filter out non qgroup-accountable extents  */
7938                 extent_type = btrfs_file_extent_type(eb, fi);
7939
7940                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
7941                         continue;
7942
7943                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
7944                 if (!bytenr)
7945                         continue;
7946
7947                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
7948         }
7949         return 0;
7950 }
7951
7952 /*
7953  * Walk up the tree from the bottom, freeing leaves and any interior
7954  * nodes which have had all slots visited. If a node (leaf or
7955  * interior) is freed, the node above it will have it's slot
7956  * incremented. The root node will never be freed.
7957  *
7958  * At the end of this function, we should have a path which has all
7959  * slots incremented to the next position for a search. If we need to
7960  * read a new node it will be NULL and the node above it will have the
7961  * correct slot selected for a later read.
7962  *
7963  * If we increment the root nodes slot counter past the number of
7964  * elements, 1 is returned to signal completion of the search.
7965  */
7966 static int adjust_slots_upwards(struct btrfs_root *root,
7967                                 struct btrfs_path *path, int root_level)
7968 {
7969         int level = 0;
7970         int nr, slot;
7971         struct extent_buffer *eb;
7972
7973         if (root_level == 0)
7974                 return 1;
7975
7976         while (level <= root_level) {
7977                 eb = path->nodes[level];
7978                 nr = btrfs_header_nritems(eb);
7979                 path->slots[level]++;
7980                 slot = path->slots[level];
7981                 if (slot >= nr || level == 0) {
7982                         /*
7983                          * Don't free the root -  we will detect this
7984                          * condition after our loop and return a
7985                          * positive value for caller to stop walking the tree.
7986                          */
7987                         if (level != root_level) {
7988                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7989                                 path->locks[level] = 0;
7990
7991                                 free_extent_buffer(eb);
7992                                 path->nodes[level] = NULL;
7993                                 path->slots[level] = 0;
7994                         }
7995                 } else {
7996                         /*
7997                          * We have a valid slot to walk back down
7998                          * from. Stop here so caller can process these
7999                          * new nodes.
8000                          */
8001                         break;
8002                 }
8003
8004                 level++;
8005         }
8006
8007         eb = path->nodes[root_level];
8008         if (path->slots[root_level] >= btrfs_header_nritems(eb))
8009                 return 1;
8010
8011         return 0;
8012 }
8013
8014 /*
8015  * root_eb is the subtree root and is locked before this function is called.
8016  * TODO: Modify this function to mark all (including complete shared node)
8017  * to dirty_extent_root to allow it get accounted in qgroup.
8018  */
8019 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8020                                   struct btrfs_root *root,
8021                                   struct extent_buffer *root_eb,
8022                                   u64 root_gen,
8023                                   int root_level)
8024 {
8025         int ret = 0;
8026         int level;
8027         struct extent_buffer *eb = root_eb;
8028         struct btrfs_path *path = NULL;
8029
8030         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8031         BUG_ON(root_eb == NULL);
8032
8033         if (!root->fs_info->quota_enabled)
8034                 return 0;
8035
8036         if (!extent_buffer_uptodate(root_eb)) {
8037                 ret = btrfs_read_buffer(root_eb, root_gen);
8038                 if (ret)
8039                         goto out;
8040         }
8041
8042         if (root_level == 0) {
8043                 ret = account_leaf_items(trans, root, root_eb);
8044                 goto out;
8045         }
8046
8047         path = btrfs_alloc_path();
8048         if (!path)
8049                 return -ENOMEM;
8050
8051         /*
8052          * Walk down the tree.  Missing extent blocks are filled in as
8053          * we go. Metadata is accounted every time we read a new
8054          * extent block.
8055          *
8056          * When we reach a leaf, we account for file extent items in it,
8057          * walk back up the tree (adjusting slot pointers as we go)
8058          * and restart the search process.
8059          */
8060         extent_buffer_get(root_eb); /* For path */
8061         path->nodes[root_level] = root_eb;
8062         path->slots[root_level] = 0;
8063         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8064 walk_down:
8065         level = root_level;
8066         while (level >= 0) {
8067                 if (path->nodes[level] == NULL) {
8068                         int parent_slot;
8069                         u64 child_gen;
8070                         u64 child_bytenr;
8071
8072                         /* We need to get child blockptr/gen from
8073                          * parent before we can read it. */
8074                         eb = path->nodes[level + 1];
8075                         parent_slot = path->slots[level + 1];
8076                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8077                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8078
8079                         eb = read_tree_block(root, child_bytenr, child_gen);
8080                         if (IS_ERR(eb)) {
8081                                 ret = PTR_ERR(eb);
8082                                 goto out;
8083                         } else if (!extent_buffer_uptodate(eb)) {
8084                                 free_extent_buffer(eb);
8085                                 ret = -EIO;
8086                                 goto out;
8087                         }
8088
8089                         path->nodes[level] = eb;
8090                         path->slots[level] = 0;
8091
8092                         btrfs_tree_read_lock(eb);
8093                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8094                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8095                 }
8096
8097                 if (level == 0) {
8098                         ret = account_leaf_items(trans, root, path->nodes[level]);
8099                         if (ret)
8100                                 goto out;
8101
8102                         /* Nonzero return here means we completed our search */
8103                         ret = adjust_slots_upwards(root, path, root_level);
8104                         if (ret)
8105                                 break;
8106
8107                         /* Restart search with new slots */
8108                         goto walk_down;
8109                 }
8110
8111                 level--;
8112         }
8113
8114         ret = 0;
8115 out:
8116         btrfs_free_path(path);
8117
8118         return ret;
8119 }
8120
8121 /*
8122  * helper to process tree block while walking down the tree.
8123  *
8124  * when wc->stage == UPDATE_BACKREF, this function updates
8125  * back refs for pointers in the block.
8126  *
8127  * NOTE: return value 1 means we should stop walking down.
8128  */
8129 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8130                                    struct btrfs_root *root,
8131                                    struct btrfs_path *path,
8132                                    struct walk_control *wc, int lookup_info)
8133 {
8134         int level = wc->level;
8135         struct extent_buffer *eb = path->nodes[level];
8136         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8137         int ret;
8138
8139         if (wc->stage == UPDATE_BACKREF &&
8140             btrfs_header_owner(eb) != root->root_key.objectid)
8141                 return 1;
8142
8143         /*
8144          * when reference count of tree block is 1, it won't increase
8145          * again. once full backref flag is set, we never clear it.
8146          */
8147         if (lookup_info &&
8148             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8149              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8150                 BUG_ON(!path->locks[level]);
8151                 ret = btrfs_lookup_extent_info(trans, root,
8152                                                eb->start, level, 1,
8153                                                &wc->refs[level],
8154                                                &wc->flags[level]);
8155                 BUG_ON(ret == -ENOMEM);
8156                 if (ret)
8157                         return ret;
8158                 BUG_ON(wc->refs[level] == 0);
8159         }
8160
8161         if (wc->stage == DROP_REFERENCE) {
8162                 if (wc->refs[level] > 1)
8163                         return 1;
8164
8165                 if (path->locks[level] && !wc->keep_locks) {
8166                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8167                         path->locks[level] = 0;
8168                 }
8169                 return 0;
8170         }
8171
8172         /* wc->stage == UPDATE_BACKREF */
8173         if (!(wc->flags[level] & flag)) {
8174                 BUG_ON(!path->locks[level]);
8175                 ret = btrfs_inc_ref(trans, root, eb, 1);
8176                 BUG_ON(ret); /* -ENOMEM */
8177                 ret = btrfs_dec_ref(trans, root, eb, 0);
8178                 BUG_ON(ret); /* -ENOMEM */
8179                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8180                                                   eb->len, flag,
8181                                                   btrfs_header_level(eb), 0);
8182                 BUG_ON(ret); /* -ENOMEM */
8183                 wc->flags[level] |= flag;
8184         }
8185
8186         /*
8187          * the block is shared by multiple trees, so it's not good to
8188          * keep the tree lock
8189          */
8190         if (path->locks[level] && level > 0) {
8191                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8192                 path->locks[level] = 0;
8193         }
8194         return 0;
8195 }
8196
8197 /*
8198  * helper to process tree block pointer.
8199  *
8200  * when wc->stage == DROP_REFERENCE, this function checks
8201  * reference count of the block pointed to. if the block
8202  * is shared and we need update back refs for the subtree
8203  * rooted at the block, this function changes wc->stage to
8204  * UPDATE_BACKREF. if the block is shared and there is no
8205  * need to update back, this function drops the reference
8206  * to the block.
8207  *
8208  * NOTE: return value 1 means we should stop walking down.
8209  */
8210 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8211                                  struct btrfs_root *root,
8212                                  struct btrfs_path *path,
8213                                  struct walk_control *wc, int *lookup_info)
8214 {
8215         u64 bytenr;
8216         u64 generation;
8217         u64 parent;
8218         u32 blocksize;
8219         struct btrfs_key key;
8220         struct extent_buffer *next;
8221         int level = wc->level;
8222         int reada = 0;
8223         int ret = 0;
8224         bool need_account = false;
8225
8226         generation = btrfs_node_ptr_generation(path->nodes[level],
8227                                                path->slots[level]);
8228         /*
8229          * if the lower level block was created before the snapshot
8230          * was created, we know there is no need to update back refs
8231          * for the subtree
8232          */
8233         if (wc->stage == UPDATE_BACKREF &&
8234             generation <= root->root_key.offset) {
8235                 *lookup_info = 1;
8236                 return 1;
8237         }
8238
8239         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8240         blocksize = root->nodesize;
8241
8242         next = btrfs_find_tree_block(root->fs_info, bytenr);
8243         if (!next) {
8244                 next = btrfs_find_create_tree_block(root, bytenr);
8245                 if (!next)
8246                         return -ENOMEM;
8247                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8248                                                level - 1);
8249                 reada = 1;
8250         }
8251         btrfs_tree_lock(next);
8252         btrfs_set_lock_blocking(next);
8253
8254         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8255                                        &wc->refs[level - 1],
8256                                        &wc->flags[level - 1]);
8257         if (ret < 0) {
8258                 btrfs_tree_unlock(next);
8259                 return ret;
8260         }
8261
8262         if (unlikely(wc->refs[level - 1] == 0)) {
8263                 btrfs_err(root->fs_info, "Missing references.");
8264                 BUG();
8265         }
8266         *lookup_info = 0;
8267
8268         if (wc->stage == DROP_REFERENCE) {
8269                 if (wc->refs[level - 1] > 1) {
8270                         need_account = true;
8271                         if (level == 1 &&
8272                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8273                                 goto skip;
8274
8275                         if (!wc->update_ref ||
8276                             generation <= root->root_key.offset)
8277                                 goto skip;
8278
8279                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8280                                               path->slots[level]);
8281                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8282                         if (ret < 0)
8283                                 goto skip;
8284
8285                         wc->stage = UPDATE_BACKREF;
8286                         wc->shared_level = level - 1;
8287                 }
8288         } else {
8289                 if (level == 1 &&
8290                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8291                         goto skip;
8292         }
8293
8294         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8295                 btrfs_tree_unlock(next);
8296                 free_extent_buffer(next);
8297                 next = NULL;
8298                 *lookup_info = 1;
8299         }
8300
8301         if (!next) {
8302                 if (reada && level == 1)
8303                         reada_walk_down(trans, root, wc, path);
8304                 next = read_tree_block(root, bytenr, generation);
8305                 if (IS_ERR(next)) {
8306                         return PTR_ERR(next);
8307                 } else if (!extent_buffer_uptodate(next)) {
8308                         free_extent_buffer(next);
8309                         return -EIO;
8310                 }
8311                 btrfs_tree_lock(next);
8312                 btrfs_set_lock_blocking(next);
8313         }
8314
8315         level--;
8316         BUG_ON(level != btrfs_header_level(next));
8317         path->nodes[level] = next;
8318         path->slots[level] = 0;
8319         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8320         wc->level = level;
8321         if (wc->level == 1)
8322                 wc->reada_slot = 0;
8323         return 0;
8324 skip:
8325         wc->refs[level - 1] = 0;
8326         wc->flags[level - 1] = 0;
8327         if (wc->stage == DROP_REFERENCE) {
8328                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8329                         parent = path->nodes[level]->start;
8330                 } else {
8331                         BUG_ON(root->root_key.objectid !=
8332                                btrfs_header_owner(path->nodes[level]));
8333                         parent = 0;
8334                 }
8335
8336                 if (need_account) {
8337                         ret = account_shared_subtree(trans, root, next,
8338                                                      generation, level - 1);
8339                         if (ret) {
8340                                 btrfs_err_rl(root->fs_info,
8341                                         "Error "
8342                                         "%d accounting shared subtree. Quota "
8343                                         "is out of sync, rescan required.",
8344                                         ret);
8345                         }
8346                 }
8347                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8348                                 root->root_key.objectid, level - 1, 0, 0);
8349                 BUG_ON(ret); /* -ENOMEM */
8350         }
8351         btrfs_tree_unlock(next);
8352         free_extent_buffer(next);
8353         *lookup_info = 1;
8354         return 1;
8355 }
8356
8357 /*
8358  * helper to process tree block while walking up the tree.
8359  *
8360  * when wc->stage == DROP_REFERENCE, this function drops
8361  * reference count on the block.
8362  *
8363  * when wc->stage == UPDATE_BACKREF, this function changes
8364  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8365  * to UPDATE_BACKREF previously while processing the block.
8366  *
8367  * NOTE: return value 1 means we should stop walking up.
8368  */
8369 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8370                                  struct btrfs_root *root,
8371                                  struct btrfs_path *path,
8372                                  struct walk_control *wc)
8373 {
8374         int ret;
8375         int level = wc->level;
8376         struct extent_buffer *eb = path->nodes[level];
8377         u64 parent = 0;
8378
8379         if (wc->stage == UPDATE_BACKREF) {
8380                 BUG_ON(wc->shared_level < level);
8381                 if (level < wc->shared_level)
8382                         goto out;
8383
8384                 ret = find_next_key(path, level + 1, &wc->update_progress);
8385                 if (ret > 0)
8386                         wc->update_ref = 0;
8387
8388                 wc->stage = DROP_REFERENCE;
8389                 wc->shared_level = -1;
8390                 path->slots[level] = 0;
8391
8392                 /*
8393                  * check reference count again if the block isn't locked.
8394                  * we should start walking down the tree again if reference
8395                  * count is one.
8396                  */
8397                 if (!path->locks[level]) {
8398                         BUG_ON(level == 0);
8399                         btrfs_tree_lock(eb);
8400                         btrfs_set_lock_blocking(eb);
8401                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8402
8403                         ret = btrfs_lookup_extent_info(trans, root,
8404                                                        eb->start, level, 1,
8405                                                        &wc->refs[level],
8406                                                        &wc->flags[level]);
8407                         if (ret < 0) {
8408                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8409                                 path->locks[level] = 0;
8410                                 return ret;
8411                         }
8412                         BUG_ON(wc->refs[level] == 0);
8413                         if (wc->refs[level] == 1) {
8414                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8415                                 path->locks[level] = 0;
8416                                 return 1;
8417                         }
8418                 }
8419         }
8420
8421         /* wc->stage == DROP_REFERENCE */
8422         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8423
8424         if (wc->refs[level] == 1) {
8425                 if (level == 0) {
8426                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8427                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8428                         else
8429                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8430                         BUG_ON(ret); /* -ENOMEM */
8431                         ret = account_leaf_items(trans, root, eb);
8432                         if (ret) {
8433                                 btrfs_err_rl(root->fs_info,
8434                                         "error "
8435                                         "%d accounting leaf items. Quota "
8436                                         "is out of sync, rescan required.",
8437                                         ret);
8438                         }
8439                 }
8440                 /* make block locked assertion in clean_tree_block happy */
8441                 if (!path->locks[level] &&
8442                     btrfs_header_generation(eb) == trans->transid) {
8443                         btrfs_tree_lock(eb);
8444                         btrfs_set_lock_blocking(eb);
8445                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8446                 }
8447                 clean_tree_block(trans, root->fs_info, eb);
8448         }
8449
8450         if (eb == root->node) {
8451                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8452                         parent = eb->start;
8453                 else
8454                         BUG_ON(root->root_key.objectid !=
8455                                btrfs_header_owner(eb));
8456         } else {
8457                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8458                         parent = path->nodes[level + 1]->start;
8459                 else
8460                         BUG_ON(root->root_key.objectid !=
8461                                btrfs_header_owner(path->nodes[level + 1]));
8462         }
8463
8464         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8465 out:
8466         wc->refs[level] = 0;
8467         wc->flags[level] = 0;
8468         return 0;
8469 }
8470
8471 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8472                                    struct btrfs_root *root,
8473                                    struct btrfs_path *path,
8474                                    struct walk_control *wc)
8475 {
8476         int level = wc->level;
8477         int lookup_info = 1;
8478         int ret;
8479
8480         while (level >= 0) {
8481                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8482                 if (ret > 0)
8483                         break;
8484
8485                 if (level == 0)
8486                         break;
8487
8488                 if (path->slots[level] >=
8489                     btrfs_header_nritems(path->nodes[level]))
8490                         break;
8491
8492                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8493                 if (ret > 0) {
8494                         path->slots[level]++;
8495                         continue;
8496                 } else if (ret < 0)
8497                         return ret;
8498                 level = wc->level;
8499         }
8500         return 0;
8501 }
8502
8503 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8504                                  struct btrfs_root *root,
8505                                  struct btrfs_path *path,
8506                                  struct walk_control *wc, int max_level)
8507 {
8508         int level = wc->level;
8509         int ret;
8510
8511         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8512         while (level < max_level && path->nodes[level]) {
8513                 wc->level = level;
8514                 if (path->slots[level] + 1 <
8515                     btrfs_header_nritems(path->nodes[level])) {
8516                         path->slots[level]++;
8517                         return 0;
8518                 } else {
8519                         ret = walk_up_proc(trans, root, path, wc);
8520                         if (ret > 0)
8521                                 return 0;
8522
8523                         if (path->locks[level]) {
8524                                 btrfs_tree_unlock_rw(path->nodes[level],
8525                                                      path->locks[level]);
8526                                 path->locks[level] = 0;
8527                         }
8528                         free_extent_buffer(path->nodes[level]);
8529                         path->nodes[level] = NULL;
8530                         level++;
8531                 }
8532         }
8533         return 1;
8534 }
8535
8536 /*
8537  * drop a subvolume tree.
8538  *
8539  * this function traverses the tree freeing any blocks that only
8540  * referenced by the tree.
8541  *
8542  * when a shared tree block is found. this function decreases its
8543  * reference count by one. if update_ref is true, this function
8544  * also make sure backrefs for the shared block and all lower level
8545  * blocks are properly updated.
8546  *
8547  * If called with for_reloc == 0, may exit early with -EAGAIN
8548  */
8549 int btrfs_drop_snapshot(struct btrfs_root *root,
8550                          struct btrfs_block_rsv *block_rsv, int update_ref,
8551                          int for_reloc)
8552 {
8553         struct btrfs_path *path;
8554         struct btrfs_trans_handle *trans;
8555         struct btrfs_root *tree_root = root->fs_info->tree_root;
8556         struct btrfs_root_item *root_item = &root->root_item;
8557         struct walk_control *wc;
8558         struct btrfs_key key;
8559         int err = 0;
8560         int ret;
8561         int level;
8562         bool root_dropped = false;
8563
8564         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
8565
8566         path = btrfs_alloc_path();
8567         if (!path) {
8568                 err = -ENOMEM;
8569                 goto out;
8570         }
8571
8572         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8573         if (!wc) {
8574                 btrfs_free_path(path);
8575                 err = -ENOMEM;
8576                 goto out;
8577         }
8578
8579         trans = btrfs_start_transaction(tree_root, 0);
8580         if (IS_ERR(trans)) {
8581                 err = PTR_ERR(trans);
8582                 goto out_free;
8583         }
8584
8585         if (block_rsv)
8586                 trans->block_rsv = block_rsv;
8587
8588         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8589                 level = btrfs_header_level(root->node);
8590                 path->nodes[level] = btrfs_lock_root_node(root);
8591                 btrfs_set_lock_blocking(path->nodes[level]);
8592                 path->slots[level] = 0;
8593                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8594                 memset(&wc->update_progress, 0,
8595                        sizeof(wc->update_progress));
8596         } else {
8597                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8598                 memcpy(&wc->update_progress, &key,
8599                        sizeof(wc->update_progress));
8600
8601                 level = root_item->drop_level;
8602                 BUG_ON(level == 0);
8603                 path->lowest_level = level;
8604                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8605                 path->lowest_level = 0;
8606                 if (ret < 0) {
8607                         err = ret;
8608                         goto out_end_trans;
8609                 }
8610                 WARN_ON(ret > 0);
8611
8612                 /*
8613                  * unlock our path, this is safe because only this
8614                  * function is allowed to delete this snapshot
8615                  */
8616                 btrfs_unlock_up_safe(path, 0);
8617
8618                 level = btrfs_header_level(root->node);
8619                 while (1) {
8620                         btrfs_tree_lock(path->nodes[level]);
8621                         btrfs_set_lock_blocking(path->nodes[level]);
8622                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8623
8624                         ret = btrfs_lookup_extent_info(trans, root,
8625                                                 path->nodes[level]->start,
8626                                                 level, 1, &wc->refs[level],
8627                                                 &wc->flags[level]);
8628                         if (ret < 0) {
8629                                 err = ret;
8630                                 goto out_end_trans;
8631                         }
8632                         BUG_ON(wc->refs[level] == 0);
8633
8634                         if (level == root_item->drop_level)
8635                                 break;
8636
8637                         btrfs_tree_unlock(path->nodes[level]);
8638                         path->locks[level] = 0;
8639                         WARN_ON(wc->refs[level] != 1);
8640                         level--;
8641                 }
8642         }
8643
8644         wc->level = level;
8645         wc->shared_level = -1;
8646         wc->stage = DROP_REFERENCE;
8647         wc->update_ref = update_ref;
8648         wc->keep_locks = 0;
8649         wc->for_reloc = for_reloc;
8650         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8651
8652         while (1) {
8653
8654                 ret = walk_down_tree(trans, root, path, wc);
8655                 if (ret < 0) {
8656                         err = ret;
8657                         break;
8658                 }
8659
8660                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8661                 if (ret < 0) {
8662                         err = ret;
8663                         break;
8664                 }
8665
8666                 if (ret > 0) {
8667                         BUG_ON(wc->stage != DROP_REFERENCE);
8668                         break;
8669                 }
8670
8671                 if (wc->stage == DROP_REFERENCE) {
8672                         level = wc->level;
8673                         btrfs_node_key(path->nodes[level],
8674                                        &root_item->drop_progress,
8675                                        path->slots[level]);
8676                         root_item->drop_level = level;
8677                 }
8678
8679                 BUG_ON(wc->level == 0);
8680                 if (btrfs_should_end_transaction(trans, tree_root) ||
8681                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
8682                         ret = btrfs_update_root(trans, tree_root,
8683                                                 &root->root_key,
8684                                                 root_item);
8685                         if (ret) {
8686                                 btrfs_abort_transaction(trans, tree_root, ret);
8687                                 err = ret;
8688                                 goto out_end_trans;
8689                         }
8690
8691                         btrfs_end_transaction_throttle(trans, tree_root);
8692                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
8693                                 pr_debug("BTRFS: drop snapshot early exit\n");
8694                                 err = -EAGAIN;
8695                                 goto out_free;
8696                         }
8697
8698                         trans = btrfs_start_transaction(tree_root, 0);
8699                         if (IS_ERR(trans)) {
8700                                 err = PTR_ERR(trans);
8701                                 goto out_free;
8702                         }
8703                         if (block_rsv)
8704                                 trans->block_rsv = block_rsv;
8705                 }
8706         }
8707         btrfs_release_path(path);
8708         if (err)
8709                 goto out_end_trans;
8710
8711         ret = btrfs_del_root(trans, tree_root, &root->root_key);
8712         if (ret) {
8713                 btrfs_abort_transaction(trans, tree_root, ret);
8714                 goto out_end_trans;
8715         }
8716
8717         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
8718                 ret = btrfs_find_root(tree_root, &root->root_key, path,
8719                                       NULL, NULL);
8720                 if (ret < 0) {
8721                         btrfs_abort_transaction(trans, tree_root, ret);
8722                         err = ret;
8723                         goto out_end_trans;
8724                 } else if (ret > 0) {
8725                         /* if we fail to delete the orphan item this time
8726                          * around, it'll get picked up the next time.
8727                          *
8728                          * The most common failure here is just -ENOENT.
8729                          */
8730                         btrfs_del_orphan_item(trans, tree_root,
8731                                               root->root_key.objectid);
8732                 }
8733         }
8734
8735         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
8736                 btrfs_add_dropped_root(trans, root);
8737         } else {
8738                 free_extent_buffer(root->node);
8739                 free_extent_buffer(root->commit_root);
8740                 btrfs_put_fs_root(root);
8741         }
8742         root_dropped = true;
8743 out_end_trans:
8744         btrfs_end_transaction_throttle(trans, tree_root);
8745 out_free:
8746         kfree(wc);
8747         btrfs_free_path(path);
8748 out:
8749         /*
8750          * So if we need to stop dropping the snapshot for whatever reason we
8751          * need to make sure to add it back to the dead root list so that we
8752          * keep trying to do the work later.  This also cleans up roots if we
8753          * don't have it in the radix (like when we recover after a power fail
8754          * or unmount) so we don't leak memory.
8755          */
8756         if (!for_reloc && root_dropped == false)
8757                 btrfs_add_dead_root(root);
8758         if (err && err != -EAGAIN)
8759                 btrfs_std_error(root->fs_info, err, NULL);
8760         return err;
8761 }
8762
8763 /*
8764  * drop subtree rooted at tree block 'node'.
8765  *
8766  * NOTE: this function will unlock and release tree block 'node'
8767  * only used by relocation code
8768  */
8769 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
8770                         struct btrfs_root *root,
8771                         struct extent_buffer *node,
8772                         struct extent_buffer *parent)
8773 {
8774         struct btrfs_path *path;
8775         struct walk_control *wc;
8776         int level;
8777         int parent_level;
8778         int ret = 0;
8779         int wret;
8780
8781         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
8782
8783         path = btrfs_alloc_path();
8784         if (!path)
8785                 return -ENOMEM;
8786
8787         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8788         if (!wc) {
8789                 btrfs_free_path(path);
8790                 return -ENOMEM;
8791         }
8792
8793         btrfs_assert_tree_locked(parent);
8794         parent_level = btrfs_header_level(parent);
8795         extent_buffer_get(parent);
8796         path->nodes[parent_level] = parent;
8797         path->slots[parent_level] = btrfs_header_nritems(parent);
8798
8799         btrfs_assert_tree_locked(node);
8800         level = btrfs_header_level(node);
8801         path->nodes[level] = node;
8802         path->slots[level] = 0;
8803         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8804
8805         wc->refs[parent_level] = 1;
8806         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8807         wc->level = level;
8808         wc->shared_level = -1;
8809         wc->stage = DROP_REFERENCE;
8810         wc->update_ref = 0;
8811         wc->keep_locks = 1;
8812         wc->for_reloc = 1;
8813         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8814
8815         while (1) {
8816                 wret = walk_down_tree(trans, root, path, wc);
8817                 if (wret < 0) {
8818                         ret = wret;
8819                         break;
8820                 }
8821
8822                 wret = walk_up_tree(trans, root, path, wc, parent_level);
8823                 if (wret < 0)
8824                         ret = wret;
8825                 if (wret != 0)
8826                         break;
8827         }
8828
8829         kfree(wc);
8830         btrfs_free_path(path);
8831         return ret;
8832 }
8833
8834 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
8835 {
8836         u64 num_devices;
8837         u64 stripped;
8838
8839         /*
8840          * if restripe for this chunk_type is on pick target profile and
8841          * return, otherwise do the usual balance
8842          */
8843         stripped = get_restripe_target(root->fs_info, flags);
8844         if (stripped)
8845                 return extended_to_chunk(stripped);
8846
8847         num_devices = root->fs_info->fs_devices->rw_devices;
8848
8849         stripped = BTRFS_BLOCK_GROUP_RAID0 |
8850                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
8851                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
8852
8853         if (num_devices == 1) {
8854                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8855                 stripped = flags & ~stripped;
8856
8857                 /* turn raid0 into single device chunks */
8858                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
8859                         return stripped;
8860
8861                 /* turn mirroring into duplication */
8862                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
8863                              BTRFS_BLOCK_GROUP_RAID10))
8864                         return stripped | BTRFS_BLOCK_GROUP_DUP;
8865         } else {
8866                 /* they already had raid on here, just return */
8867                 if (flags & stripped)
8868                         return flags;
8869
8870                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8871                 stripped = flags & ~stripped;
8872
8873                 /* switch duplicated blocks with raid1 */
8874                 if (flags & BTRFS_BLOCK_GROUP_DUP)
8875                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
8876
8877                 /* this is drive concat, leave it alone */
8878         }
8879
8880         return flags;
8881 }
8882
8883 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
8884 {
8885         struct btrfs_space_info *sinfo = cache->space_info;
8886         u64 num_bytes;
8887         u64 min_allocable_bytes;
8888         int ret = -ENOSPC;
8889
8890         /*
8891          * We need some metadata space and system metadata space for
8892          * allocating chunks in some corner cases until we force to set
8893          * it to be readonly.
8894          */
8895         if ((sinfo->flags &
8896              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
8897             !force)
8898                 min_allocable_bytes = 1 * 1024 * 1024;
8899         else
8900                 min_allocable_bytes = 0;
8901
8902         spin_lock(&sinfo->lock);
8903         spin_lock(&cache->lock);
8904
8905         if (cache->ro) {
8906                 cache->ro++;
8907                 ret = 0;
8908                 goto out;
8909         }
8910
8911         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8912                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8913
8914         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
8915             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
8916             min_allocable_bytes <= sinfo->total_bytes) {
8917                 sinfo->bytes_readonly += num_bytes;
8918                 cache->ro++;
8919                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
8920                 ret = 0;
8921         }
8922 out:
8923         spin_unlock(&cache->lock);
8924         spin_unlock(&sinfo->lock);
8925         return ret;
8926 }
8927
8928 int btrfs_inc_block_group_ro(struct btrfs_root *root,
8929                              struct btrfs_block_group_cache *cache)
8930
8931 {
8932         struct btrfs_trans_handle *trans;
8933         u64 alloc_flags;
8934         int ret;
8935
8936 again:
8937         trans = btrfs_join_transaction(root);
8938         if (IS_ERR(trans))
8939                 return PTR_ERR(trans);
8940
8941         /*
8942          * we're not allowed to set block groups readonly after the dirty
8943          * block groups cache has started writing.  If it already started,
8944          * back off and let this transaction commit
8945          */
8946         mutex_lock(&root->fs_info->ro_block_group_mutex);
8947         if (trans->transaction->dirty_bg_run) {
8948                 u64 transid = trans->transid;
8949
8950                 mutex_unlock(&root->fs_info->ro_block_group_mutex);
8951                 btrfs_end_transaction(trans, root);
8952
8953                 ret = btrfs_wait_for_commit(root, transid);
8954                 if (ret)
8955                         return ret;
8956                 goto again;
8957         }
8958
8959         /*
8960          * if we are changing raid levels, try to allocate a corresponding
8961          * block group with the new raid level.
8962          */
8963         alloc_flags = update_block_group_flags(root, cache->flags);
8964         if (alloc_flags != cache->flags) {
8965                 ret = do_chunk_alloc(trans, root, alloc_flags,
8966                                      CHUNK_ALLOC_FORCE);
8967                 /*
8968                  * ENOSPC is allowed here, we may have enough space
8969                  * already allocated at the new raid level to
8970                  * carry on
8971                  */
8972                 if (ret == -ENOSPC)
8973                         ret = 0;
8974                 if (ret < 0)
8975                         goto out;
8976         }
8977
8978         ret = inc_block_group_ro(cache, 0);
8979         if (!ret)
8980                 goto out;
8981         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
8982         ret = do_chunk_alloc(trans, root, alloc_flags,
8983                              CHUNK_ALLOC_FORCE);
8984         if (ret < 0)
8985                 goto out;
8986         ret = inc_block_group_ro(cache, 0);
8987 out:
8988         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
8989                 alloc_flags = update_block_group_flags(root, cache->flags);
8990                 lock_chunks(root->fs_info->chunk_root);
8991                 check_system_chunk(trans, root, alloc_flags);
8992                 unlock_chunks(root->fs_info->chunk_root);
8993         }
8994         mutex_unlock(&root->fs_info->ro_block_group_mutex);
8995
8996         btrfs_end_transaction(trans, root);
8997         return ret;
8998 }
8999
9000 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9001                             struct btrfs_root *root, u64 type)
9002 {
9003         u64 alloc_flags = get_alloc_profile(root, type);
9004         return do_chunk_alloc(trans, root, alloc_flags,
9005                               CHUNK_ALLOC_FORCE);
9006 }
9007
9008 /*
9009  * helper to account the unused space of all the readonly block group in the
9010  * space_info. takes mirrors into account.
9011  */
9012 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9013 {
9014         struct btrfs_block_group_cache *block_group;
9015         u64 free_bytes = 0;
9016         int factor;
9017
9018         /* It's df, we don't care if it's racey */
9019         if (list_empty(&sinfo->ro_bgs))
9020                 return 0;
9021
9022         spin_lock(&sinfo->lock);
9023         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9024                 spin_lock(&block_group->lock);
9025
9026                 if (!block_group->ro) {
9027                         spin_unlock(&block_group->lock);
9028                         continue;
9029                 }
9030
9031                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9032                                           BTRFS_BLOCK_GROUP_RAID10 |
9033                                           BTRFS_BLOCK_GROUP_DUP))
9034                         factor = 2;
9035                 else
9036                         factor = 1;
9037
9038                 free_bytes += (block_group->key.offset -
9039                                btrfs_block_group_used(&block_group->item)) *
9040                                factor;
9041
9042                 spin_unlock(&block_group->lock);
9043         }
9044         spin_unlock(&sinfo->lock);
9045
9046         return free_bytes;
9047 }
9048
9049 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9050                               struct btrfs_block_group_cache *cache)
9051 {
9052         struct btrfs_space_info *sinfo = cache->space_info;
9053         u64 num_bytes;
9054
9055         BUG_ON(!cache->ro);
9056
9057         spin_lock(&sinfo->lock);
9058         spin_lock(&cache->lock);
9059         if (!--cache->ro) {
9060                 num_bytes = cache->key.offset - cache->reserved -
9061                             cache->pinned - cache->bytes_super -
9062                             btrfs_block_group_used(&cache->item);
9063                 sinfo->bytes_readonly -= num_bytes;
9064                 list_del_init(&cache->ro_list);
9065         }
9066         spin_unlock(&cache->lock);
9067         spin_unlock(&sinfo->lock);
9068 }
9069
9070 /*
9071  * checks to see if its even possible to relocate this block group.
9072  *
9073  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9074  * ok to go ahead and try.
9075  */
9076 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9077 {
9078         struct btrfs_block_group_cache *block_group;
9079         struct btrfs_space_info *space_info;
9080         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9081         struct btrfs_device *device;
9082         struct btrfs_trans_handle *trans;
9083         u64 min_free;
9084         u64 dev_min = 1;
9085         u64 dev_nr = 0;
9086         u64 target;
9087         int index;
9088         int full = 0;
9089         int ret = 0;
9090
9091         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9092
9093         /* odd, couldn't find the block group, leave it alone */
9094         if (!block_group)
9095                 return -1;
9096
9097         min_free = btrfs_block_group_used(&block_group->item);
9098
9099         /* no bytes used, we're good */
9100         if (!min_free)
9101                 goto out;
9102
9103         space_info = block_group->space_info;
9104         spin_lock(&space_info->lock);
9105
9106         full = space_info->full;
9107
9108         /*
9109          * if this is the last block group we have in this space, we can't
9110          * relocate it unless we're able to allocate a new chunk below.
9111          *
9112          * Otherwise, we need to make sure we have room in the space to handle
9113          * all of the extents from this block group.  If we can, we're good
9114          */
9115         if ((space_info->total_bytes != block_group->key.offset) &&
9116             (space_info->bytes_used + space_info->bytes_reserved +
9117              space_info->bytes_pinned + space_info->bytes_readonly +
9118              min_free < space_info->total_bytes)) {
9119                 spin_unlock(&space_info->lock);
9120                 goto out;
9121         }
9122         spin_unlock(&space_info->lock);
9123
9124         /*
9125          * ok we don't have enough space, but maybe we have free space on our
9126          * devices to allocate new chunks for relocation, so loop through our
9127          * alloc devices and guess if we have enough space.  if this block
9128          * group is going to be restriped, run checks against the target
9129          * profile instead of the current one.
9130          */
9131         ret = -1;
9132
9133         /*
9134          * index:
9135          *      0: raid10
9136          *      1: raid1
9137          *      2: dup
9138          *      3: raid0
9139          *      4: single
9140          */
9141         target = get_restripe_target(root->fs_info, block_group->flags);
9142         if (target) {
9143                 index = __get_raid_index(extended_to_chunk(target));
9144         } else {
9145                 /*
9146                  * this is just a balance, so if we were marked as full
9147                  * we know there is no space for a new chunk
9148                  */
9149                 if (full)
9150                         goto out;
9151
9152                 index = get_block_group_index(block_group);
9153         }
9154
9155         if (index == BTRFS_RAID_RAID10) {
9156                 dev_min = 4;
9157                 /* Divide by 2 */
9158                 min_free >>= 1;
9159         } else if (index == BTRFS_RAID_RAID1) {
9160                 dev_min = 2;
9161         } else if (index == BTRFS_RAID_DUP) {
9162                 /* Multiply by 2 */
9163                 min_free <<= 1;
9164         } else if (index == BTRFS_RAID_RAID0) {
9165                 dev_min = fs_devices->rw_devices;
9166                 min_free = div64_u64(min_free, dev_min);
9167         }
9168
9169         /* We need to do this so that we can look at pending chunks */
9170         trans = btrfs_join_transaction(root);
9171         if (IS_ERR(trans)) {
9172                 ret = PTR_ERR(trans);
9173                 goto out;
9174         }
9175
9176         mutex_lock(&root->fs_info->chunk_mutex);
9177         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9178                 u64 dev_offset;
9179
9180                 /*
9181                  * check to make sure we can actually find a chunk with enough
9182                  * space to fit our block group in.
9183                  */
9184                 if (device->total_bytes > device->bytes_used + min_free &&
9185                     !device->is_tgtdev_for_dev_replace) {
9186                         ret = find_free_dev_extent(trans, device, min_free,
9187                                                    &dev_offset, NULL);
9188                         if (!ret)
9189                                 dev_nr++;
9190
9191                         if (dev_nr >= dev_min)
9192                                 break;
9193
9194                         ret = -1;
9195                 }
9196         }
9197         mutex_unlock(&root->fs_info->chunk_mutex);
9198         btrfs_end_transaction(trans, root);
9199 out:
9200         btrfs_put_block_group(block_group);
9201         return ret;
9202 }
9203
9204 static int find_first_block_group(struct btrfs_root *root,
9205                 struct btrfs_path *path, struct btrfs_key *key)
9206 {
9207         int ret = 0;
9208         struct btrfs_key found_key;
9209         struct extent_buffer *leaf;
9210         int slot;
9211
9212         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9213         if (ret < 0)
9214                 goto out;
9215
9216         while (1) {
9217                 slot = path->slots[0];
9218                 leaf = path->nodes[0];
9219                 if (slot >= btrfs_header_nritems(leaf)) {
9220                         ret = btrfs_next_leaf(root, path);
9221                         if (ret == 0)
9222                                 continue;
9223                         if (ret < 0)
9224                                 goto out;
9225                         break;
9226                 }
9227                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9228
9229                 if (found_key.objectid >= key->objectid &&
9230                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9231                         ret = 0;
9232                         goto out;
9233                 }
9234                 path->slots[0]++;
9235         }
9236 out:
9237         return ret;
9238 }
9239
9240 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9241 {
9242         struct btrfs_block_group_cache *block_group;
9243         u64 last = 0;
9244
9245         while (1) {
9246                 struct inode *inode;
9247
9248                 block_group = btrfs_lookup_first_block_group(info, last);
9249                 while (block_group) {
9250                         spin_lock(&block_group->lock);
9251                         if (block_group->iref)
9252                                 break;
9253                         spin_unlock(&block_group->lock);
9254                         block_group = next_block_group(info->tree_root,
9255                                                        block_group);
9256                 }
9257                 if (!block_group) {
9258                         if (last == 0)
9259                                 break;
9260                         last = 0;
9261                         continue;
9262                 }
9263
9264                 inode = block_group->inode;
9265                 block_group->iref = 0;
9266                 block_group->inode = NULL;
9267                 spin_unlock(&block_group->lock);
9268                 iput(inode);
9269                 last = block_group->key.objectid + block_group->key.offset;
9270                 btrfs_put_block_group(block_group);
9271         }
9272 }
9273
9274 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9275 {
9276         struct btrfs_block_group_cache *block_group;
9277         struct btrfs_space_info *space_info;
9278         struct btrfs_caching_control *caching_ctl;
9279         struct rb_node *n;
9280
9281         down_write(&info->commit_root_sem);
9282         while (!list_empty(&info->caching_block_groups)) {
9283                 caching_ctl = list_entry(info->caching_block_groups.next,
9284                                          struct btrfs_caching_control, list);
9285                 list_del(&caching_ctl->list);
9286                 put_caching_control(caching_ctl);
9287         }
9288         up_write(&info->commit_root_sem);
9289
9290         spin_lock(&info->unused_bgs_lock);
9291         while (!list_empty(&info->unused_bgs)) {
9292                 block_group = list_first_entry(&info->unused_bgs,
9293                                                struct btrfs_block_group_cache,
9294                                                bg_list);
9295                 list_del_init(&block_group->bg_list);
9296                 btrfs_put_block_group(block_group);
9297         }
9298         spin_unlock(&info->unused_bgs_lock);
9299
9300         spin_lock(&info->block_group_cache_lock);
9301         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9302                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9303                                        cache_node);
9304                 rb_erase(&block_group->cache_node,
9305                          &info->block_group_cache_tree);
9306                 RB_CLEAR_NODE(&block_group->cache_node);
9307                 spin_unlock(&info->block_group_cache_lock);
9308
9309                 down_write(&block_group->space_info->groups_sem);
9310                 list_del(&block_group->list);
9311                 up_write(&block_group->space_info->groups_sem);
9312
9313                 if (block_group->cached == BTRFS_CACHE_STARTED)
9314                         wait_block_group_cache_done(block_group);
9315
9316                 /*
9317                  * We haven't cached this block group, which means we could
9318                  * possibly have excluded extents on this block group.
9319                  */
9320                 if (block_group->cached == BTRFS_CACHE_NO ||
9321                     block_group->cached == BTRFS_CACHE_ERROR)
9322                         free_excluded_extents(info->extent_root, block_group);
9323
9324                 btrfs_remove_free_space_cache(block_group);
9325                 btrfs_put_block_group(block_group);
9326
9327                 spin_lock(&info->block_group_cache_lock);
9328         }
9329         spin_unlock(&info->block_group_cache_lock);
9330
9331         /* now that all the block groups are freed, go through and
9332          * free all the space_info structs.  This is only called during
9333          * the final stages of unmount, and so we know nobody is
9334          * using them.  We call synchronize_rcu() once before we start,
9335          * just to be on the safe side.
9336          */
9337         synchronize_rcu();
9338
9339         release_global_block_rsv(info);
9340
9341         while (!list_empty(&info->space_info)) {
9342                 int i;
9343
9344                 space_info = list_entry(info->space_info.next,
9345                                         struct btrfs_space_info,
9346                                         list);
9347                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
9348                         if (WARN_ON(space_info->bytes_pinned > 0 ||
9349                             space_info->bytes_reserved > 0 ||
9350                             space_info->bytes_may_use > 0)) {
9351                                 dump_space_info(space_info, 0, 0);
9352                         }
9353                 }
9354                 list_del(&space_info->list);
9355                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9356                         struct kobject *kobj;
9357                         kobj = space_info->block_group_kobjs[i];
9358                         space_info->block_group_kobjs[i] = NULL;
9359                         if (kobj) {
9360                                 kobject_del(kobj);
9361                                 kobject_put(kobj);
9362                         }
9363                 }
9364                 kobject_del(&space_info->kobj);
9365                 kobject_put(&space_info->kobj);
9366         }
9367         return 0;
9368 }
9369
9370 static void __link_block_group(struct btrfs_space_info *space_info,
9371                                struct btrfs_block_group_cache *cache)
9372 {
9373         int index = get_block_group_index(cache);
9374         bool first = false;
9375
9376         down_write(&space_info->groups_sem);
9377         if (list_empty(&space_info->block_groups[index]))
9378                 first = true;
9379         list_add_tail(&cache->list, &space_info->block_groups[index]);
9380         up_write(&space_info->groups_sem);
9381
9382         if (first) {
9383                 struct raid_kobject *rkobj;
9384                 int ret;
9385
9386                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9387                 if (!rkobj)
9388                         goto out_err;
9389                 rkobj->raid_type = index;
9390                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9391                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9392                                   "%s", get_raid_name(index));
9393                 if (ret) {
9394                         kobject_put(&rkobj->kobj);
9395                         goto out_err;
9396                 }
9397                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9398         }
9399
9400         return;
9401 out_err:
9402         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
9403 }
9404
9405 static struct btrfs_block_group_cache *
9406 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
9407 {
9408         struct btrfs_block_group_cache *cache;
9409
9410         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9411         if (!cache)
9412                 return NULL;
9413
9414         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9415                                         GFP_NOFS);
9416         if (!cache->free_space_ctl) {
9417                 kfree(cache);
9418                 return NULL;
9419         }
9420
9421         cache->key.objectid = start;
9422         cache->key.offset = size;
9423         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9424
9425         cache->sectorsize = root->sectorsize;
9426         cache->fs_info = root->fs_info;
9427         cache->full_stripe_len = btrfs_full_stripe_len(root,
9428                                                &root->fs_info->mapping_tree,
9429                                                start);
9430         atomic_set(&cache->count, 1);
9431         spin_lock_init(&cache->lock);
9432         init_rwsem(&cache->data_rwsem);
9433         INIT_LIST_HEAD(&cache->list);
9434         INIT_LIST_HEAD(&cache->cluster_list);
9435         INIT_LIST_HEAD(&cache->bg_list);
9436         INIT_LIST_HEAD(&cache->ro_list);
9437         INIT_LIST_HEAD(&cache->dirty_list);
9438         INIT_LIST_HEAD(&cache->io_list);
9439         btrfs_init_free_space_ctl(cache);
9440         atomic_set(&cache->trimming, 0);
9441
9442         return cache;
9443 }
9444
9445 int btrfs_read_block_groups(struct btrfs_root *root)
9446 {
9447         struct btrfs_path *path;
9448         int ret;
9449         struct btrfs_block_group_cache *cache;
9450         struct btrfs_fs_info *info = root->fs_info;
9451         struct btrfs_space_info *space_info;
9452         struct btrfs_key key;
9453         struct btrfs_key found_key;
9454         struct extent_buffer *leaf;
9455         int need_clear = 0;
9456         u64 cache_gen;
9457
9458         root = info->extent_root;
9459         key.objectid = 0;
9460         key.offset = 0;
9461         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9462         path = btrfs_alloc_path();
9463         if (!path)
9464                 return -ENOMEM;
9465         path->reada = 1;
9466
9467         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
9468         if (btrfs_test_opt(root, SPACE_CACHE) &&
9469             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
9470                 need_clear = 1;
9471         if (btrfs_test_opt(root, CLEAR_CACHE))
9472                 need_clear = 1;
9473
9474         while (1) {
9475                 ret = find_first_block_group(root, path, &key);
9476                 if (ret > 0)
9477                         break;
9478                 if (ret != 0)
9479                         goto error;
9480
9481                 leaf = path->nodes[0];
9482                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9483
9484                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
9485                                                        found_key.offset);
9486                 if (!cache) {
9487                         ret = -ENOMEM;
9488                         goto error;
9489                 }
9490
9491                 if (need_clear) {
9492                         /*
9493                          * When we mount with old space cache, we need to
9494                          * set BTRFS_DC_CLEAR and set dirty flag.
9495                          *
9496                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9497                          *    truncate the old free space cache inode and
9498                          *    setup a new one.
9499                          * b) Setting 'dirty flag' makes sure that we flush
9500                          *    the new space cache info onto disk.
9501                          */
9502                         if (btrfs_test_opt(root, SPACE_CACHE))
9503                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9504                 }
9505
9506                 read_extent_buffer(leaf, &cache->item,
9507                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9508                                    sizeof(cache->item));
9509                 cache->flags = btrfs_block_group_flags(&cache->item);
9510
9511                 key.objectid = found_key.objectid + found_key.offset;
9512                 btrfs_release_path(path);
9513
9514                 /*
9515                  * We need to exclude the super stripes now so that the space
9516                  * info has super bytes accounted for, otherwise we'll think
9517                  * we have more space than we actually do.
9518                  */
9519                 ret = exclude_super_stripes(root, cache);
9520                 if (ret) {
9521                         /*
9522                          * We may have excluded something, so call this just in
9523                          * case.
9524                          */
9525                         free_excluded_extents(root, cache);
9526                         btrfs_put_block_group(cache);
9527                         goto error;
9528                 }
9529
9530                 /*
9531                  * check for two cases, either we are full, and therefore
9532                  * don't need to bother with the caching work since we won't
9533                  * find any space, or we are empty, and we can just add all
9534                  * the space in and be done with it.  This saves us _alot_ of
9535                  * time, particularly in the full case.
9536                  */
9537                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
9538                         cache->last_byte_to_unpin = (u64)-1;
9539                         cache->cached = BTRFS_CACHE_FINISHED;
9540                         free_excluded_extents(root, cache);
9541                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9542                         cache->last_byte_to_unpin = (u64)-1;
9543                         cache->cached = BTRFS_CACHE_FINISHED;
9544                         add_new_free_space(cache, root->fs_info,
9545                                            found_key.objectid,
9546                                            found_key.objectid +
9547                                            found_key.offset);
9548                         free_excluded_extents(root, cache);
9549                 }
9550
9551                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
9552                 if (ret) {
9553                         btrfs_remove_free_space_cache(cache);
9554                         btrfs_put_block_group(cache);
9555                         goto error;
9556                 }
9557
9558                 ret = update_space_info(info, cache->flags, found_key.offset,
9559                                         btrfs_block_group_used(&cache->item),
9560                                         &space_info);
9561                 if (ret) {
9562                         btrfs_remove_free_space_cache(cache);
9563                         spin_lock(&info->block_group_cache_lock);
9564                         rb_erase(&cache->cache_node,
9565                                  &info->block_group_cache_tree);
9566                         RB_CLEAR_NODE(&cache->cache_node);
9567                         spin_unlock(&info->block_group_cache_lock);
9568                         btrfs_put_block_group(cache);
9569                         goto error;
9570                 }
9571
9572                 cache->space_info = space_info;
9573                 spin_lock(&cache->space_info->lock);
9574                 cache->space_info->bytes_readonly += cache->bytes_super;
9575                 spin_unlock(&cache->space_info->lock);
9576
9577                 __link_block_group(space_info, cache);
9578
9579                 set_avail_alloc_bits(root->fs_info, cache->flags);
9580                 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
9581                         inc_block_group_ro(cache, 1);
9582                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9583                         spin_lock(&info->unused_bgs_lock);
9584                         /* Should always be true but just in case. */
9585                         if (list_empty(&cache->bg_list)) {
9586                                 btrfs_get_block_group(cache);
9587                                 list_add_tail(&cache->bg_list,
9588                                               &info->unused_bgs);
9589                         }
9590                         spin_unlock(&info->unused_bgs_lock);
9591                 }
9592         }
9593
9594         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
9595                 if (!(get_alloc_profile(root, space_info->flags) &
9596                       (BTRFS_BLOCK_GROUP_RAID10 |
9597                        BTRFS_BLOCK_GROUP_RAID1 |
9598                        BTRFS_BLOCK_GROUP_RAID5 |
9599                        BTRFS_BLOCK_GROUP_RAID6 |
9600                        BTRFS_BLOCK_GROUP_DUP)))
9601                         continue;
9602                 /*
9603                  * avoid allocating from un-mirrored block group if there are
9604                  * mirrored block groups.
9605                  */
9606                 list_for_each_entry(cache,
9607                                 &space_info->block_groups[BTRFS_RAID_RAID0],
9608                                 list)
9609                         inc_block_group_ro(cache, 1);
9610                 list_for_each_entry(cache,
9611                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
9612                                 list)
9613                         inc_block_group_ro(cache, 1);
9614         }
9615
9616         init_global_block_rsv(info);
9617         ret = 0;
9618 error:
9619         btrfs_free_path(path);
9620         return ret;
9621 }
9622
9623 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
9624                                        struct btrfs_root *root)
9625 {
9626         struct btrfs_block_group_cache *block_group, *tmp;
9627         struct btrfs_root *extent_root = root->fs_info->extent_root;
9628         struct btrfs_block_group_item item;
9629         struct btrfs_key key;
9630         int ret = 0;
9631         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
9632
9633         trans->can_flush_pending_bgs = false;
9634         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
9635                 if (ret)
9636                         goto next;
9637
9638                 spin_lock(&block_group->lock);
9639                 memcpy(&item, &block_group->item, sizeof(item));
9640                 memcpy(&key, &block_group->key, sizeof(key));
9641                 spin_unlock(&block_group->lock);
9642
9643                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
9644                                         sizeof(item));
9645                 if (ret)
9646                         btrfs_abort_transaction(trans, extent_root, ret);
9647                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
9648                                                key.objectid, key.offset);
9649                 if (ret)
9650                         btrfs_abort_transaction(trans, extent_root, ret);
9651 next:
9652                 list_del_init(&block_group->bg_list);
9653         }
9654         trans->can_flush_pending_bgs = can_flush_pending_bgs;
9655 }
9656
9657 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
9658                            struct btrfs_root *root, u64 bytes_used,
9659                            u64 type, u64 chunk_objectid, u64 chunk_offset,
9660                            u64 size)
9661 {
9662         int ret;
9663         struct btrfs_root *extent_root;
9664         struct btrfs_block_group_cache *cache;
9665
9666         extent_root = root->fs_info->extent_root;
9667
9668         btrfs_set_log_full_commit(root->fs_info, trans);
9669
9670         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
9671         if (!cache)
9672                 return -ENOMEM;
9673
9674         btrfs_set_block_group_used(&cache->item, bytes_used);
9675         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
9676         btrfs_set_block_group_flags(&cache->item, type);
9677
9678         cache->flags = type;
9679         cache->last_byte_to_unpin = (u64)-1;
9680         cache->cached = BTRFS_CACHE_FINISHED;
9681         ret = exclude_super_stripes(root, cache);
9682         if (ret) {
9683                 /*
9684                  * We may have excluded something, so call this just in
9685                  * case.
9686                  */
9687                 free_excluded_extents(root, cache);
9688                 btrfs_put_block_group(cache);
9689                 return ret;
9690         }
9691
9692         add_new_free_space(cache, root->fs_info, chunk_offset,
9693                            chunk_offset + size);
9694
9695         free_excluded_extents(root, cache);
9696
9697         /*
9698          * Call to ensure the corresponding space_info object is created and
9699          * assigned to our block group, but don't update its counters just yet.
9700          * We want our bg to be added to the rbtree with its ->space_info set.
9701          */
9702         ret = update_space_info(root->fs_info, cache->flags, 0, 0,
9703                                 &cache->space_info);
9704         if (ret) {
9705                 btrfs_remove_free_space_cache(cache);
9706                 btrfs_put_block_group(cache);
9707                 return ret;
9708         }
9709
9710         ret = btrfs_add_block_group_cache(root->fs_info, cache);
9711         if (ret) {
9712                 btrfs_remove_free_space_cache(cache);
9713                 btrfs_put_block_group(cache);
9714                 return ret;
9715         }
9716
9717         /*
9718          * Now that our block group has its ->space_info set and is inserted in
9719          * the rbtree, update the space info's counters.
9720          */
9721         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
9722                                 &cache->space_info);
9723         if (ret) {
9724                 btrfs_remove_free_space_cache(cache);
9725                 spin_lock(&root->fs_info->block_group_cache_lock);
9726                 rb_erase(&cache->cache_node,
9727                          &root->fs_info->block_group_cache_tree);
9728                 RB_CLEAR_NODE(&cache->cache_node);
9729                 spin_unlock(&root->fs_info->block_group_cache_lock);
9730                 btrfs_put_block_group(cache);
9731                 return ret;
9732         }
9733         update_global_block_rsv(root->fs_info);
9734
9735         spin_lock(&cache->space_info->lock);
9736         cache->space_info->bytes_readonly += cache->bytes_super;
9737         spin_unlock(&cache->space_info->lock);
9738
9739         __link_block_group(cache->space_info, cache);
9740
9741         list_add_tail(&cache->bg_list, &trans->new_bgs);
9742
9743         set_avail_alloc_bits(extent_root->fs_info, type);
9744
9745         return 0;
9746 }
9747
9748 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
9749 {
9750         u64 extra_flags = chunk_to_extended(flags) &
9751                                 BTRFS_EXTENDED_PROFILE_MASK;
9752
9753         write_seqlock(&fs_info->profiles_lock);
9754         if (flags & BTRFS_BLOCK_GROUP_DATA)
9755                 fs_info->avail_data_alloc_bits &= ~extra_flags;
9756         if (flags & BTRFS_BLOCK_GROUP_METADATA)
9757                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
9758         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
9759                 fs_info->avail_system_alloc_bits &= ~extra_flags;
9760         write_sequnlock(&fs_info->profiles_lock);
9761 }
9762
9763 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
9764                              struct btrfs_root *root, u64 group_start,
9765                              struct extent_map *em)
9766 {
9767         struct btrfs_path *path;
9768         struct btrfs_block_group_cache *block_group;
9769         struct btrfs_free_cluster *cluster;
9770         struct btrfs_root *tree_root = root->fs_info->tree_root;
9771         struct btrfs_key key;
9772         struct inode *inode;
9773         struct kobject *kobj = NULL;
9774         int ret;
9775         int index;
9776         int factor;
9777         struct btrfs_caching_control *caching_ctl = NULL;
9778         bool remove_em;
9779
9780         root = root->fs_info->extent_root;
9781
9782         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
9783         BUG_ON(!block_group);
9784         BUG_ON(!block_group->ro);
9785
9786         /*
9787          * Free the reserved super bytes from this block group before
9788          * remove it.
9789          */
9790         free_excluded_extents(root, block_group);
9791
9792         memcpy(&key, &block_group->key, sizeof(key));
9793         index = get_block_group_index(block_group);
9794         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
9795                                   BTRFS_BLOCK_GROUP_RAID1 |
9796                                   BTRFS_BLOCK_GROUP_RAID10))
9797                 factor = 2;
9798         else
9799                 factor = 1;
9800
9801         /* make sure this block group isn't part of an allocation cluster */
9802         cluster = &root->fs_info->data_alloc_cluster;
9803         spin_lock(&cluster->refill_lock);
9804         btrfs_return_cluster_to_free_space(block_group, cluster);
9805         spin_unlock(&cluster->refill_lock);
9806
9807         /*
9808          * make sure this block group isn't part of a metadata
9809          * allocation cluster
9810          */
9811         cluster = &root->fs_info->meta_alloc_cluster;
9812         spin_lock(&cluster->refill_lock);
9813         btrfs_return_cluster_to_free_space(block_group, cluster);
9814         spin_unlock(&cluster->refill_lock);
9815
9816         path = btrfs_alloc_path();
9817         if (!path) {
9818                 ret = -ENOMEM;
9819                 goto out;
9820         }
9821
9822         /*
9823          * get the inode first so any iput calls done for the io_list
9824          * aren't the final iput (no unlinks allowed now)
9825          */
9826         inode = lookup_free_space_inode(tree_root, block_group, path);
9827
9828         mutex_lock(&trans->transaction->cache_write_mutex);
9829         /*
9830          * make sure our free spache cache IO is done before remove the
9831          * free space inode
9832          */
9833         spin_lock(&trans->transaction->dirty_bgs_lock);
9834         if (!list_empty(&block_group->io_list)) {
9835                 list_del_init(&block_group->io_list);
9836
9837                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
9838
9839                 spin_unlock(&trans->transaction->dirty_bgs_lock);
9840                 btrfs_wait_cache_io(root, trans, block_group,
9841                                     &block_group->io_ctl, path,
9842                                     block_group->key.objectid);
9843                 btrfs_put_block_group(block_group);
9844                 spin_lock(&trans->transaction->dirty_bgs_lock);
9845         }
9846
9847         if (!list_empty(&block_group->dirty_list)) {
9848                 list_del_init(&block_group->dirty_list);
9849                 btrfs_put_block_group(block_group);
9850         }
9851         spin_unlock(&trans->transaction->dirty_bgs_lock);
9852         mutex_unlock(&trans->transaction->cache_write_mutex);
9853
9854         if (!IS_ERR(inode)) {
9855                 ret = btrfs_orphan_add(trans, inode);
9856                 if (ret) {
9857                         btrfs_add_delayed_iput(inode);
9858                         goto out;
9859                 }
9860                 clear_nlink(inode);
9861                 /* One for the block groups ref */
9862                 spin_lock(&block_group->lock);
9863                 if (block_group->iref) {
9864                         block_group->iref = 0;
9865                         block_group->inode = NULL;
9866                         spin_unlock(&block_group->lock);
9867                         iput(inode);
9868                 } else {
9869                         spin_unlock(&block_group->lock);
9870                 }
9871                 /* One for our lookup ref */
9872                 btrfs_add_delayed_iput(inode);
9873         }
9874
9875         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
9876         key.offset = block_group->key.objectid;
9877         key.type = 0;
9878
9879         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
9880         if (ret < 0)
9881                 goto out;
9882         if (ret > 0)
9883                 btrfs_release_path(path);
9884         if (ret == 0) {
9885                 ret = btrfs_del_item(trans, tree_root, path);
9886                 if (ret)
9887                         goto out;
9888                 btrfs_release_path(path);
9889         }
9890
9891         spin_lock(&root->fs_info->block_group_cache_lock);
9892         rb_erase(&block_group->cache_node,
9893                  &root->fs_info->block_group_cache_tree);
9894         RB_CLEAR_NODE(&block_group->cache_node);
9895
9896         if (root->fs_info->first_logical_byte == block_group->key.objectid)
9897                 root->fs_info->first_logical_byte = (u64)-1;
9898         spin_unlock(&root->fs_info->block_group_cache_lock);
9899
9900         down_write(&block_group->space_info->groups_sem);
9901         /*
9902          * we must use list_del_init so people can check to see if they
9903          * are still on the list after taking the semaphore
9904          */
9905         list_del_init(&block_group->list);
9906         if (list_empty(&block_group->space_info->block_groups[index])) {
9907                 kobj = block_group->space_info->block_group_kobjs[index];
9908                 block_group->space_info->block_group_kobjs[index] = NULL;
9909                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
9910         }
9911         up_write(&block_group->space_info->groups_sem);
9912         if (kobj) {
9913                 kobject_del(kobj);
9914                 kobject_put(kobj);
9915         }
9916
9917         if (block_group->has_caching_ctl)
9918                 caching_ctl = get_caching_control(block_group);
9919         if (block_group->cached == BTRFS_CACHE_STARTED)
9920                 wait_block_group_cache_done(block_group);
9921         if (block_group->has_caching_ctl) {
9922                 down_write(&root->fs_info->commit_root_sem);
9923                 if (!caching_ctl) {
9924                         struct btrfs_caching_control *ctl;
9925
9926                         list_for_each_entry(ctl,
9927                                     &root->fs_info->caching_block_groups, list)
9928                                 if (ctl->block_group == block_group) {
9929                                         caching_ctl = ctl;
9930                                         atomic_inc(&caching_ctl->count);
9931                                         break;
9932                                 }
9933                 }
9934                 if (caching_ctl)
9935                         list_del_init(&caching_ctl->list);
9936                 up_write(&root->fs_info->commit_root_sem);
9937                 if (caching_ctl) {
9938                         /* Once for the caching bgs list and once for us. */
9939                         put_caching_control(caching_ctl);
9940                         put_caching_control(caching_ctl);
9941                 }
9942         }
9943
9944         spin_lock(&trans->transaction->dirty_bgs_lock);
9945         if (!list_empty(&block_group->dirty_list)) {
9946                 WARN_ON(1);
9947         }
9948         if (!list_empty(&block_group->io_list)) {
9949                 WARN_ON(1);
9950         }
9951         spin_unlock(&trans->transaction->dirty_bgs_lock);
9952         btrfs_remove_free_space_cache(block_group);
9953
9954         spin_lock(&block_group->space_info->lock);
9955         list_del_init(&block_group->ro_list);
9956
9957         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
9958                 WARN_ON(block_group->space_info->total_bytes
9959                         < block_group->key.offset);
9960                 WARN_ON(block_group->space_info->bytes_readonly
9961                         < block_group->key.offset);
9962                 WARN_ON(block_group->space_info->disk_total
9963                         < block_group->key.offset * factor);
9964         }
9965         block_group->space_info->total_bytes -= block_group->key.offset;
9966         block_group->space_info->bytes_readonly -= block_group->key.offset;
9967         block_group->space_info->disk_total -= block_group->key.offset * factor;
9968
9969         spin_unlock(&block_group->space_info->lock);
9970
9971         memcpy(&key, &block_group->key, sizeof(key));
9972
9973         lock_chunks(root);
9974         if (!list_empty(&em->list)) {
9975                 /* We're in the transaction->pending_chunks list. */
9976                 free_extent_map(em);
9977         }
9978         spin_lock(&block_group->lock);
9979         block_group->removed = 1;
9980         /*
9981          * At this point trimming can't start on this block group, because we
9982          * removed the block group from the tree fs_info->block_group_cache_tree
9983          * so no one can't find it anymore and even if someone already got this
9984          * block group before we removed it from the rbtree, they have already
9985          * incremented block_group->trimming - if they didn't, they won't find
9986          * any free space entries because we already removed them all when we
9987          * called btrfs_remove_free_space_cache().
9988          *
9989          * And we must not remove the extent map from the fs_info->mapping_tree
9990          * to prevent the same logical address range and physical device space
9991          * ranges from being reused for a new block group. This is because our
9992          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
9993          * completely transactionless, so while it is trimming a range the
9994          * currently running transaction might finish and a new one start,
9995          * allowing for new block groups to be created that can reuse the same
9996          * physical device locations unless we take this special care.
9997          *
9998          * There may also be an implicit trim operation if the file system
9999          * is mounted with -odiscard. The same protections must remain
10000          * in place until the extents have been discarded completely when
10001          * the transaction commit has completed.
10002          */
10003         remove_em = (atomic_read(&block_group->trimming) == 0);
10004         /*
10005          * Make sure a trimmer task always sees the em in the pinned_chunks list
10006          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10007          * before checking block_group->removed).
10008          */
10009         if (!remove_em) {
10010                 /*
10011                  * Our em might be in trans->transaction->pending_chunks which
10012                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10013                  * and so is the fs_info->pinned_chunks list.
10014                  *
10015                  * So at this point we must be holding the chunk_mutex to avoid
10016                  * any races with chunk allocation (more specifically at
10017                  * volumes.c:contains_pending_extent()), to ensure it always
10018                  * sees the em, either in the pending_chunks list or in the
10019                  * pinned_chunks list.
10020                  */
10021                 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10022         }
10023         spin_unlock(&block_group->lock);
10024
10025         if (remove_em) {
10026                 struct extent_map_tree *em_tree;
10027
10028                 em_tree = &root->fs_info->mapping_tree.map_tree;
10029                 write_lock(&em_tree->lock);
10030                 /*
10031                  * The em might be in the pending_chunks list, so make sure the
10032                  * chunk mutex is locked, since remove_extent_mapping() will
10033                  * delete us from that list.
10034                  */
10035                 remove_extent_mapping(em_tree, em);
10036                 write_unlock(&em_tree->lock);
10037                 /* once for the tree */
10038                 free_extent_map(em);
10039         }
10040
10041         unlock_chunks(root);
10042
10043         btrfs_put_block_group(block_group);
10044         btrfs_put_block_group(block_group);
10045
10046         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10047         if (ret > 0)
10048                 ret = -EIO;
10049         if (ret < 0)
10050                 goto out;
10051
10052         ret = btrfs_del_item(trans, root, path);
10053 out:
10054         btrfs_free_path(path);
10055         return ret;
10056 }
10057
10058 /*
10059  * Process the unused_bgs list and remove any that don't have any allocated
10060  * space inside of them.
10061  */
10062 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10063 {
10064         struct btrfs_block_group_cache *block_group;
10065         struct btrfs_space_info *space_info;
10066         struct btrfs_root *root = fs_info->extent_root;
10067         struct btrfs_trans_handle *trans;
10068         int ret = 0;
10069
10070         if (!fs_info->open)
10071                 return;
10072
10073         spin_lock(&fs_info->unused_bgs_lock);
10074         while (!list_empty(&fs_info->unused_bgs)) {
10075                 u64 start, end;
10076                 int trimming;
10077
10078                 block_group = list_first_entry(&fs_info->unused_bgs,
10079                                                struct btrfs_block_group_cache,
10080                                                bg_list);
10081                 space_info = block_group->space_info;
10082                 list_del_init(&block_group->bg_list);
10083                 if (ret || btrfs_mixed_space_info(space_info)) {
10084                         btrfs_put_block_group(block_group);
10085                         continue;
10086                 }
10087                 spin_unlock(&fs_info->unused_bgs_lock);
10088
10089                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
10090
10091                 /* Don't want to race with allocators so take the groups_sem */
10092                 down_write(&space_info->groups_sem);
10093                 spin_lock(&block_group->lock);
10094                 if (block_group->reserved ||
10095                     btrfs_block_group_used(&block_group->item) ||
10096                     block_group->ro) {
10097                         /*
10098                          * We want to bail if we made new allocations or have
10099                          * outstanding allocations in this block group.  We do
10100                          * the ro check in case balance is currently acting on
10101                          * this block group.
10102                          */
10103                         spin_unlock(&block_group->lock);
10104                         up_write(&space_info->groups_sem);
10105                         goto next;
10106                 }
10107                 spin_unlock(&block_group->lock);
10108
10109                 /* We don't want to force the issue, only flip if it's ok. */
10110                 ret = inc_block_group_ro(block_group, 0);
10111                 up_write(&space_info->groups_sem);
10112                 if (ret < 0) {
10113                         ret = 0;
10114                         goto next;
10115                 }
10116
10117                 /*
10118                  * Want to do this before we do anything else so we can recover
10119                  * properly if we fail to join the transaction.
10120                  */
10121                 /* 1 for btrfs_orphan_reserve_metadata() */
10122                 trans = btrfs_start_transaction(root, 1);
10123                 if (IS_ERR(trans)) {
10124                         btrfs_dec_block_group_ro(root, block_group);
10125                         ret = PTR_ERR(trans);
10126                         goto next;
10127                 }
10128
10129                 /*
10130                  * We could have pending pinned extents for this block group,
10131                  * just delete them, we don't care about them anymore.
10132                  */
10133                 start = block_group->key.objectid;
10134                 end = start + block_group->key.offset - 1;
10135                 /*
10136                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10137                  * btrfs_finish_extent_commit(). If we are at transaction N,
10138                  * another task might be running finish_extent_commit() for the
10139                  * previous transaction N - 1, and have seen a range belonging
10140                  * to the block group in freed_extents[] before we were able to
10141                  * clear the whole block group range from freed_extents[]. This
10142                  * means that task can lookup for the block group after we
10143                  * unpinned it from freed_extents[] and removed it, leading to
10144                  * a BUG_ON() at btrfs_unpin_extent_range().
10145                  */
10146                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10147                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10148                                   EXTENT_DIRTY, GFP_NOFS);
10149                 if (ret) {
10150                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10151                         btrfs_dec_block_group_ro(root, block_group);
10152                         goto end_trans;
10153                 }
10154                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10155                                   EXTENT_DIRTY, GFP_NOFS);
10156                 if (ret) {
10157                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10158                         btrfs_dec_block_group_ro(root, block_group);
10159                         goto end_trans;
10160                 }
10161                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10162
10163                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10164                 spin_lock(&space_info->lock);
10165                 spin_lock(&block_group->lock);
10166
10167                 space_info->bytes_pinned -= block_group->pinned;
10168                 space_info->bytes_readonly += block_group->pinned;
10169                 percpu_counter_add(&space_info->total_bytes_pinned,
10170                                    -block_group->pinned);
10171                 block_group->pinned = 0;
10172
10173                 spin_unlock(&block_group->lock);
10174                 spin_unlock(&space_info->lock);
10175
10176                 /* DISCARD can flip during remount */
10177                 trimming = btrfs_test_opt(root, DISCARD);
10178
10179                 /* Implicit trim during transaction commit. */
10180                 if (trimming)
10181                         btrfs_get_block_group_trimming(block_group);
10182
10183                 /*
10184                  * Btrfs_remove_chunk will abort the transaction if things go
10185                  * horribly wrong.
10186                  */
10187                 ret = btrfs_remove_chunk(trans, root,
10188                                          block_group->key.objectid);
10189
10190                 if (ret) {
10191                         if (trimming)
10192                                 btrfs_put_block_group_trimming(block_group);
10193                         goto end_trans;
10194                 }
10195
10196                 /*
10197                  * If we're not mounted with -odiscard, we can just forget
10198                  * about this block group. Otherwise we'll need to wait
10199                  * until transaction commit to do the actual discard.
10200                  */
10201                 if (trimming) {
10202                         WARN_ON(!list_empty(&block_group->bg_list));
10203                         spin_lock(&trans->transaction->deleted_bgs_lock);
10204                         list_move(&block_group->bg_list,
10205                                   &trans->transaction->deleted_bgs);
10206                         spin_unlock(&trans->transaction->deleted_bgs_lock);
10207                         btrfs_get_block_group(block_group);
10208                 }
10209 end_trans:
10210                 btrfs_end_transaction(trans, root);
10211 next:
10212                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
10213                 btrfs_put_block_group(block_group);
10214                 spin_lock(&fs_info->unused_bgs_lock);
10215         }
10216         spin_unlock(&fs_info->unused_bgs_lock);
10217 }
10218
10219 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10220 {
10221         struct btrfs_space_info *space_info;
10222         struct btrfs_super_block *disk_super;
10223         u64 features;
10224         u64 flags;
10225         int mixed = 0;
10226         int ret;
10227
10228         disk_super = fs_info->super_copy;
10229         if (!btrfs_super_root(disk_super))
10230                 return 1;
10231
10232         features = btrfs_super_incompat_flags(disk_super);
10233         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10234                 mixed = 1;
10235
10236         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10237         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10238         if (ret)
10239                 goto out;
10240
10241         if (mixed) {
10242                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10243                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10244         } else {
10245                 flags = BTRFS_BLOCK_GROUP_METADATA;
10246                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10247                 if (ret)
10248                         goto out;
10249
10250                 flags = BTRFS_BLOCK_GROUP_DATA;
10251                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10252         }
10253 out:
10254         return ret;
10255 }
10256
10257 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10258 {
10259         return unpin_extent_range(root, start, end, false);
10260 }
10261
10262 /*
10263  * It used to be that old block groups would be left around forever.
10264  * Iterating over them would be enough to trim unused space.  Since we
10265  * now automatically remove them, we also need to iterate over unallocated
10266  * space.
10267  *
10268  * We don't want a transaction for this since the discard may take a
10269  * substantial amount of time.  We don't require that a transaction be
10270  * running, but we do need to take a running transaction into account
10271  * to ensure that we're not discarding chunks that were released in
10272  * the current transaction.
10273  *
10274  * Holding the chunks lock will prevent other threads from allocating
10275  * or releasing chunks, but it won't prevent a running transaction
10276  * from committing and releasing the memory that the pending chunks
10277  * list head uses.  For that, we need to take a reference to the
10278  * transaction.
10279  */
10280 static int btrfs_trim_free_extents(struct btrfs_device *device,
10281                                    u64 minlen, u64 *trimmed)
10282 {
10283         u64 start = 0, len = 0;
10284         int ret;
10285
10286         *trimmed = 0;
10287
10288         /* Not writeable = nothing to do. */
10289         if (!device->writeable)
10290                 return 0;
10291
10292         /* No free space = nothing to do. */
10293         if (device->total_bytes <= device->bytes_used)
10294                 return 0;
10295
10296         ret = 0;
10297
10298         while (1) {
10299                 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
10300                 struct btrfs_transaction *trans;
10301                 u64 bytes;
10302
10303                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10304                 if (ret)
10305                         return ret;
10306
10307                 down_read(&fs_info->commit_root_sem);
10308
10309                 spin_lock(&fs_info->trans_lock);
10310                 trans = fs_info->running_transaction;
10311                 if (trans)
10312                         atomic_inc(&trans->use_count);
10313                 spin_unlock(&fs_info->trans_lock);
10314
10315                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10316                                                  &start, &len);
10317                 if (trans)
10318                         btrfs_put_transaction(trans);
10319
10320                 if (ret) {
10321                         up_read(&fs_info->commit_root_sem);
10322                         mutex_unlock(&fs_info->chunk_mutex);
10323                         if (ret == -ENOSPC)
10324                                 ret = 0;
10325                         break;
10326                 }
10327
10328                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10329                 up_read(&fs_info->commit_root_sem);
10330                 mutex_unlock(&fs_info->chunk_mutex);
10331
10332                 if (ret)
10333                         break;
10334
10335                 start += len;
10336                 *trimmed += bytes;
10337
10338                 if (fatal_signal_pending(current)) {
10339                         ret = -ERESTARTSYS;
10340                         break;
10341                 }
10342
10343                 cond_resched();
10344         }
10345
10346         return ret;
10347 }
10348
10349 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
10350 {
10351         struct btrfs_fs_info *fs_info = root->fs_info;
10352         struct btrfs_block_group_cache *cache = NULL;
10353         struct btrfs_device *device;
10354         struct list_head *devices;
10355         u64 group_trimmed;
10356         u64 start;
10357         u64 end;
10358         u64 trimmed = 0;
10359         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10360         int ret = 0;
10361
10362         /*
10363          * try to trim all FS space, our block group may start from non-zero.
10364          */
10365         if (range->len == total_bytes)
10366                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10367         else
10368                 cache = btrfs_lookup_block_group(fs_info, range->start);
10369
10370         while (cache) {
10371                 if (cache->key.objectid >= (range->start + range->len)) {
10372                         btrfs_put_block_group(cache);
10373                         break;
10374                 }
10375
10376                 start = max(range->start, cache->key.objectid);
10377                 end = min(range->start + range->len,
10378                                 cache->key.objectid + cache->key.offset);
10379
10380                 if (end - start >= range->minlen) {
10381                         if (!block_group_cache_done(cache)) {
10382                                 ret = cache_block_group(cache, 0);
10383                                 if (ret) {
10384                                         btrfs_put_block_group(cache);
10385                                         break;
10386                                 }
10387                                 ret = wait_block_group_cache_done(cache);
10388                                 if (ret) {
10389                                         btrfs_put_block_group(cache);
10390                                         break;
10391                                 }
10392                         }
10393                         ret = btrfs_trim_block_group(cache,
10394                                                      &group_trimmed,
10395                                                      start,
10396                                                      end,
10397                                                      range->minlen);
10398
10399                         trimmed += group_trimmed;
10400                         if (ret) {
10401                                 btrfs_put_block_group(cache);
10402                                 break;
10403                         }
10404                 }
10405
10406                 cache = next_block_group(fs_info->tree_root, cache);
10407         }
10408
10409         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
10410         devices = &root->fs_info->fs_devices->alloc_list;
10411         list_for_each_entry(device, devices, dev_alloc_list) {
10412                 ret = btrfs_trim_free_extents(device, range->minlen,
10413                                               &group_trimmed);
10414                 if (ret)
10415                         break;
10416
10417                 trimmed += group_trimmed;
10418         }
10419         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
10420
10421         range->len = trimmed;
10422         return ret;
10423 }
10424
10425 /*
10426  * btrfs_{start,end}_write_no_snapshoting() are similar to
10427  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10428  * data into the page cache through nocow before the subvolume is snapshoted,
10429  * but flush the data into disk after the snapshot creation, or to prevent
10430  * operations while snapshoting is ongoing and that cause the snapshot to be
10431  * inconsistent (writes followed by expanding truncates for example).
10432  */
10433 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
10434 {
10435         percpu_counter_dec(&root->subv_writers->counter);
10436         /*
10437          * Make sure counter is updated before we wake up waiters.
10438          */
10439         smp_mb();
10440         if (waitqueue_active(&root->subv_writers->wait))
10441                 wake_up(&root->subv_writers->wait);
10442 }
10443
10444 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
10445 {
10446         if (atomic_read(&root->will_be_snapshoted))
10447                 return 0;
10448
10449         percpu_counter_inc(&root->subv_writers->counter);
10450         /*
10451          * Make sure counter is updated before we check for snapshot creation.
10452          */
10453         smp_mb();
10454         if (atomic_read(&root->will_be_snapshoted)) {
10455                 btrfs_end_write_no_snapshoting(root);
10456                 return 0;
10457         }
10458         return 1;
10459 }