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 "compat.h"
  28 #include "hash.h"
  29 #include "ctree.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "transaction.h"
  33 #include "volumes.h"
  34 #include "raid56.h"
  35 #include "locking.h"
  36 #include "free-space-cache.h"
  37 #include "math.h"
  38
  39 #undef SCRAMBLE_DELAYED_REFS
  40
  41 /*
  42  * control flags for do_chunk_alloc's force field
  43  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  44  * if we really need one.
  45  *
  46  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  47  * if we have very few chunks already allocated.  This is
  48  * used as part of the clustering code to help make sure
  49  * we have a good pool of storage to cluster in, without
  50  * filling the FS with empty chunks
  51  *
  52  * CHUNK_ALLOC_FORCE means it must try to allocate one
  53  *
  54  */
  55 enum {
  56         CHUNK_ALLOC_NO_FORCE = 0,
  57         CHUNK_ALLOC_LIMITED = 1,
  58         CHUNK_ALLOC_FORCE = 2,
  59 };
  60
  61 /*
  62  * Control how reservations are dealt with.
  63  *
  64  * RESERVE_FREE - freeing a reservation.
  65  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  66  *   ENOSPC accounting
  67  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  68  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  69  */
  70 enum {
  71         RESERVE_FREE = 0,
  72         RESERVE_ALLOC = 1,
  73         RESERVE_ALLOC_NO_ACCOUNT = 2,
  74 };
  75
  76 static int update_block_group(struct btrfs_root *root,
  77                               u64 bytenr, u64 num_bytes, int alloc);
  78 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  79                                 struct btrfs_root *root,
  80                                 u64 bytenr, u64 num_bytes, u64 parent,
  81                                 u64 root_objectid, u64 owner_objectid,
  82                                 u64 owner_offset, int refs_to_drop,
  83                                 struct btrfs_delayed_extent_op *extra_op);
  84 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  85                                     struct extent_buffer *leaf,
  86                                     struct btrfs_extent_item *ei);
  87 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  88                                       struct btrfs_root *root,
  89                                       u64 parent, u64 root_objectid,
  90                                       u64 flags, u64 owner, u64 offset,
  91                                       struct btrfs_key *ins, int ref_mod);
  92 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  93                                      struct btrfs_root *root,
  94                                      u64 parent, u64 root_objectid,
  95                                      u64 flags, struct btrfs_disk_key *key,
  96                                      int level, struct btrfs_key *ins);
  97 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  98                           struct btrfs_root *extent_root, u64 flags,
  99                           int force);
 100 static int find_next_key(struct btrfs_path *path, int level,
 101                          struct btrfs_key *key);
 102 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 103                             int dump_block_groups);
 104 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 105                                        u64 num_bytes, int reserve);
 106 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 107                                u64 num_bytes);
 108 int btrfs_pin_extent(struct btrfs_root *root,
 109                      u64 bytenr, u64 num_bytes, int reserved);
 110
 111 static noinline int
 112 block_group_cache_done(struct btrfs_block_group_cache *cache)
 113 {
 114         smp_mb();
 115         return cache->cached == BTRFS_CACHE_FINISHED;
 116 }
 117
 118 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 119 {
 120         return (cache->flags & bits) == bits;
 121 }
 122
 123 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 124 {
 125         atomic_inc(&cache->count);
 126 }
 127
 128 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 129 {
 130         if (atomic_dec_and_test(&cache->count)) {
 131                 WARN_ON(cache->pinned > 0);
 132                 WARN_ON(cache->reserved > 0);
 133                 kfree(cache->free_space_ctl);
 134                 kfree(cache);
 135         }
 136 }
 137
 138 /*
 139  * this adds the block group to the fs_info rb tree for the block group
 140  * cache
 141  */
 142 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 143                                 struct btrfs_block_group_cache *block_group)
 144 {
 145         struct rb_node **p;
 146         struct rb_node *parent = NULL;
 147         struct btrfs_block_group_cache *cache;
 148
 149         spin_lock(&info->block_group_cache_lock);
 150         p = &info->block_group_cache_tree.rb_node;
 151
 152         while (*p) {
 153                 parent = *p;
 154                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 155                                  cache_node);
 156                 if (block_group->key.objectid < cache->key.objectid) {
 157                         p = &(*p)->rb_left;
 158                 } else if (block_group->key.objectid > cache->key.objectid) {
 159                         p = &(*p)->rb_right;
 160                 } else {
 161                         spin_unlock(&info->block_group_cache_lock);
 162                         return -EEXIST;
 163                 }
 164         }
 165
 166         rb_link_node(&block_group->cache_node, parent, p);
 167         rb_insert_color(&block_group->cache_node,
 168                         &info->block_group_cache_tree);
 169
 170         if (info->first_logical_byte > block_group->key.objectid)
 171                 info->first_logical_byte = block_group->key.objectid;
 172
 173         spin_unlock(&info->block_group_cache_lock);
 174
 175         return 0;
 176 }
 177
 178 /*
 179  * This will return the block group at or after bytenr if contains is 0, else
 180  * it will return the block group that contains the bytenr
 181  */
 182 static struct btrfs_block_group_cache *
 183 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 184                               int contains)
 185 {
 186         struct btrfs_block_group_cache *cache, *ret = NULL;
 187         struct rb_node *n;
 188         u64 end, start;
 189
 190         spin_lock(&info->block_group_cache_lock);
 191         n = info->block_group_cache_tree.rb_node;
 192
 193         while (n) {
 194                 cache = rb_entry(n, struct btrfs_block_group_cache,
 195                                  cache_node);
 196                 end = cache->key.objectid + cache->key.offset - 1;
 197                 start = cache->key.objectid;
 198
 199                 if (bytenr < start) {
 200                         if (!contains && (!ret || start < ret->key.objectid))
 201                                 ret = cache;
 202                         n = n->rb_left;
 203                 } else if (bytenr > start) {
 204                         if (contains && bytenr <= end) {
 205                                 ret = cache;
 206                                 break;
 207                         }
 208                         n = n->rb_right;
 209                 } else {
 210                         ret = cache;
 211                         break;
 212                 }
 213         }
 214         if (ret) {
 215                 btrfs_get_block_group(ret);
 216                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 217                         info->first_logical_byte = ret->key.objectid;
 218         }
 219         spin_unlock(&info->block_group_cache_lock);
 220
 221         return ret;
 222 }
 223
 224 static int add_excluded_extent(struct btrfs_root *root,
 225                                u64 start, u64 num_bytes)
 226 {
 227         u64 end = start + num_bytes - 1;
 228         set_extent_bits(&root->fs_info->freed_extents[0],
 229                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 230         set_extent_bits(&root->fs_info->freed_extents[1],
 231                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 232         return 0;
 233 }
 234
 235 static void free_excluded_extents(struct btrfs_root *root,
 236                                   struct btrfs_block_group_cache *cache)
 237 {
 238         u64 start, end;
 239
 240         start = cache->key.objectid;
 241         end = start + cache->key.offset - 1;
 242
 243         clear_extent_bits(&root->fs_info->freed_extents[0],
 244                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 245         clear_extent_bits(&root->fs_info->freed_extents[1],
 246                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 247 }
 248
 249 static int exclude_super_stripes(struct btrfs_root *root,
 250                                  struct btrfs_block_group_cache *cache)
 251 {
 252         u64 bytenr;
 253         u64 *logical;
 254         int stripe_len;
 255         int i, nr, ret;
 256
 257         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 258                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 259                 cache->bytes_super += stripe_len;
 260                 ret = add_excluded_extent(root, cache->key.objectid,
 261                                           stripe_len);
 262                 if (ret)
 263                         return ret;
 264         }
 265
 266         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 267                 bytenr = btrfs_sb_offset(i);
 268                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 269                                        cache->key.objectid, bytenr,
 270                                        0, &logical, &nr, &stripe_len);
 271                 if (ret)
 272                         return ret;
 273
 274                 while (nr--) {
 275                         u64 start, len;
 276
 277                         if (logical[nr] > cache->key.objectid +
 278                             cache->key.offset)
 279                                 continue;
 280
 281                         if (logical[nr] + stripe_len <= cache->key.objectid)
 282                                 continue;
 283
 284                         start = logical[nr];
 285                         if (start < cache->key.objectid) {
 286                                 start = cache->key.objectid;
 287                                 len = (logical[nr] + stripe_len) - start;
 288                         } else {
 289                                 len = min_t(u64, stripe_len,
 290                                             cache->key.objectid +
 291                                             cache->key.offset - start);
 292                         }
 293
 294                         cache->bytes_super += len;
 295                         ret = add_excluded_extent(root, start, len);
 296                         if (ret) {
 297                                 kfree(logical);
 298                                 return ret;
 299                         }
 300                 }
 301
 302                 kfree(logical);
 303         }
 304         return 0;
 305 }
 306
 307 static struct btrfs_caching_control *
 308 get_caching_control(struct btrfs_block_group_cache *cache)
 309 {
 310         struct btrfs_caching_control *ctl;
 311
 312         spin_lock(&cache->lock);
 313         if (cache->cached != BTRFS_CACHE_STARTED) {
 314                 spin_unlock(&cache->lock);
 315                 return NULL;
 316         }
 317
 318         /* We're loading it the fast way, so we don't have a caching_ctl. */
 319         if (!cache->caching_ctl) {
 320                 spin_unlock(&cache->lock);
 321                 return NULL;
 322         }
 323
 324         ctl = cache->caching_ctl;
 325         atomic_inc(&ctl->count);
 326         spin_unlock(&cache->lock);
 327         return ctl;
 328 }
 329
 330 static void put_caching_control(struct btrfs_caching_control *ctl)
 331 {
 332         if (atomic_dec_and_test(&ctl->count))
 333                 kfree(ctl);
 334 }
 335
 336 /*
 337  * this is only called by cache_block_group, since we could have freed extents
 338  * we need to check the pinned_extents for any extents that can't be used yet
 339  * since their free space will be released as soon as the transaction commits.
 340  */
 341 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 342                               struct btrfs_fs_info *info, u64 start, u64 end)
 343 {
 344         u64 extent_start, extent_end, size, total_added = 0;
 345         int ret;
 346
 347         while (start < end) {
 348                 ret = find_first_extent_bit(info->pinned_extents, start,
 349                                             &extent_start, &extent_end,
 350                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 351                                             NULL);
 352                 if (ret)
 353                         break;
 354
 355                 if (extent_start <= start) {
 356                         start = extent_end + 1;
 357                 } else if (extent_start > start && extent_start < end) {
 358                         size = extent_start - start;
 359                         total_added += size;
 360                         ret = btrfs_add_free_space(block_group, start,
 361                                                    size);
 362                         BUG_ON(ret); /* -ENOMEM or logic error */
 363                         start = extent_end + 1;
 364                 } else {
 365                         break;
 366                 }
 367         }
 368
 369         if (start < end) {
 370                 size = end - start;
 371                 total_added += size;
 372                 ret = btrfs_add_free_space(block_group, start, size);
 373                 BUG_ON(ret); /* -ENOMEM or logic error */
 374         }
 375
 376         return total_added;
 377 }
 378
 379 static noinline void caching_thread(struct btrfs_work *work)
 380 {
 381         struct btrfs_block_group_cache *block_group;
 382         struct btrfs_fs_info *fs_info;
 383         struct btrfs_caching_control *caching_ctl;
 384         struct btrfs_root *extent_root;
 385         struct btrfs_path *path;
 386         struct extent_buffer *leaf;
 387         struct btrfs_key key;
 388         u64 total_found = 0;
 389         u64 last = 0;
 390         u32 nritems;
 391         int ret = 0;
 392
 393         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 394         block_group = caching_ctl->block_group;
 395         fs_info = block_group->fs_info;
 396         extent_root = fs_info->extent_root;
 397
 398         path = btrfs_alloc_path();
 399         if (!path)
 400                 goto out;
 401
 402         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 403
 404         /*
 405          * We don't want to deadlock with somebody trying to allocate a new
 406          * extent for the extent root while also trying to search the extent
 407          * root to add free space.  So we skip locking and search the commit
 408          * root, since its read-only
 409          */
 410         path->skip_locking = 1;
 411         path->search_commit_root = 1;
 412         path->reada = 1;
 413
 414         key.objectid = last;
 415         key.offset = 0;
 416         key.type = BTRFS_EXTENT_ITEM_KEY;
 417 again:
 418         mutex_lock(&caching_ctl->mutex);
 419         /* need to make sure the commit_root doesn't disappear */
 420         down_read(&fs_info->extent_commit_sem);
 421
 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                                 caching_ctl->progress = last;
 444                                 btrfs_release_path(path);
 445                                 up_read(&fs_info->extent_commit_sem);
 446                                 mutex_unlock(&caching_ctl->mutex);
 447                                 cond_resched();
 448                                 goto again;
 449                         }
 450
 451                         ret = btrfs_next_leaf(extent_root, path);
 452                         if (ret < 0)
 453                                 goto err;
 454                         if (ret)
 455                                 break;
 456                         leaf = path->nodes[0];
 457                         nritems = btrfs_header_nritems(leaf);
 458                         continue;
 459                 }
 460
 461                 if (key.objectid < block_group->key.objectid) {
 462                         path->slots[0]++;
 463                         continue;
 464                 }
 465
 466                 if (key.objectid >= block_group->key.objectid +
 467                     block_group->key.offset)
 468                         break;
 469
 470                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 471                     key.type == BTRFS_METADATA_ITEM_KEY) {
 472                         total_found += add_new_free_space(block_group,
 473                                                           fs_info, last,
 474                                                           key.objectid);
 475                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 476                                 last = key.objectid +
 477                                         fs_info->tree_root->leafsize;
 478                         else
 479                                 last = key.objectid + key.offset;
 480
 481                         if (total_found > (1024 * 1024 * 2)) {
 482                                 total_found = 0;
 483                                 wake_up(&caching_ctl->wait);
 484                         }
 485                 }
 486                 path->slots[0]++;
 487         }
 488         ret = 0;
 489
 490         total_found += add_new_free_space(block_group, fs_info, last,
 491                                           block_group->key.objectid +
 492                                           block_group->key.offset);
 493         caching_ctl->progress = (u64)-1;
 494
 495         spin_lock(&block_group->lock);
 496         block_group->caching_ctl = NULL;
 497         block_group->cached = BTRFS_CACHE_FINISHED;
 498         spin_unlock(&block_group->lock);
 499
 500 err:
 501         btrfs_free_path(path);
 502         up_read(&fs_info->extent_commit_sem);
 503
 504         free_excluded_extents(extent_root, block_group);
 505
 506         mutex_unlock(&caching_ctl->mutex);
 507 out:
 508         wake_up(&caching_ctl->wait);
 509
 510         put_caching_control(caching_ctl);
 511         btrfs_put_block_group(block_group);
 512 }
 513
 514 static int cache_block_group(struct btrfs_block_group_cache *cache,
 515                              int load_cache_only)
 516 {
 517         DEFINE_WAIT(wait);
 518         struct btrfs_fs_info *fs_info = cache->fs_info;
 519         struct btrfs_caching_control *caching_ctl;
 520         int ret = 0;
 521
 522         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 523         if (!caching_ctl)
 524                 return -ENOMEM;
 525
 526         INIT_LIST_HEAD(&caching_ctl->list);
 527         mutex_init(&caching_ctl->mutex);
 528         init_waitqueue_head(&caching_ctl->wait);
 529         caching_ctl->block_group = cache;
 530         caching_ctl->progress = cache->key.objectid;
 531         atomic_set(&caching_ctl->count, 1);
 532         caching_ctl->work.func = caching_thread;
 533
 534         spin_lock(&cache->lock);
 535         /*
 536          * This should be a rare occasion, but this could happen I think in the
 537          * case where one thread starts to load the space cache info, and then
 538          * some other thread starts a transaction commit which tries to do an
 539          * allocation while the other thread is still loading the space cache
 540          * info.  The previous loop should have kept us from choosing this block
 541          * group, but if we've moved to the state where we will wait on caching
 542          * block groups we need to first check if we're doing a fast load here,
 543          * so we can wait for it to finish, otherwise we could end up allocating
 544          * from a block group who's cache gets evicted for one reason or
 545          * another.
 546          */
 547         while (cache->cached == BTRFS_CACHE_FAST) {
 548                 struct btrfs_caching_control *ctl;
 549
 550                 ctl = cache->caching_ctl;
 551                 atomic_inc(&ctl->count);
 552                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 553                 spin_unlock(&cache->lock);
 554
 555                 schedule();
 556
 557                 finish_wait(&ctl->wait, &wait);
 558                 put_caching_control(ctl);
 559                 spin_lock(&cache->lock);
 560         }
 561
 562         if (cache->cached != BTRFS_CACHE_NO) {
 563                 spin_unlock(&cache->lock);
 564                 kfree(caching_ctl);
 565                 return 0;
 566         }
 567         WARN_ON(cache->caching_ctl);
 568         cache->caching_ctl = caching_ctl;
 569         cache->cached = BTRFS_CACHE_FAST;
 570         spin_unlock(&cache->lock);
 571
 572         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 573                 ret = load_free_space_cache(fs_info, cache);
 574
 575                 spin_lock(&cache->lock);
 576                 if (ret == 1) {
 577                         cache->caching_ctl = NULL;
 578                         cache->cached = BTRFS_CACHE_FINISHED;
 579                         cache->last_byte_to_unpin = (u64)-1;
 580                 } else {
 581                         if (load_cache_only) {
 582                                 cache->caching_ctl = NULL;
 583                                 cache->cached = BTRFS_CACHE_NO;
 584                         } else {
 585                                 cache->cached = BTRFS_CACHE_STARTED;
 586                         }
 587                 }
 588                 spin_unlock(&cache->lock);
 589                 wake_up(&caching_ctl->wait);
 590                 if (ret == 1) {
 591                         put_caching_control(caching_ctl);
 592                         free_excluded_extents(fs_info->extent_root, cache);
 593                         return 0;
 594                 }
 595         } else {
 596                 /*
 597                  * We are not going to do the fast caching, set cached to the
 598                  * appropriate value and wakeup any waiters.
 599                  */
 600                 spin_lock(&cache->lock);
 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                 }
 607                 spin_unlock(&cache->lock);
 608                 wake_up(&caching_ctl->wait);
 609         }
 610
 611         if (load_cache_only) {
 612                 put_caching_control(caching_ctl);
 613                 return 0;
 614         }
 615
 616         down_write(&fs_info->extent_commit_sem);
 617         atomic_inc(&caching_ctl->count);
 618         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 619         up_write(&fs_info->extent_commit_sem);
 620
 621         btrfs_get_block_group(cache);
 622
 623         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 624
 625         return ret;
 626 }
 627
 628 /*
 629  * return the block group that starts at or after bytenr
 630  */
 631 static struct btrfs_block_group_cache *
 632 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 633 {
 634         struct btrfs_block_group_cache *cache;
 635
 636         cache = block_group_cache_tree_search(info, bytenr, 0);
 637
 638         return cache;
 639 }
 640
 641 /*
 642  * return the block group that contains the given bytenr
 643  */
 644 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 645                                                  struct btrfs_fs_info *info,
 646                                                  u64 bytenr)
 647 {
 648         struct btrfs_block_group_cache *cache;
 649
 650         cache = block_group_cache_tree_search(info, bytenr, 1);
 651
 652         return cache;
 653 }
 654
 655 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 656                                                   u64 flags)
 657 {
 658         struct list_head *head = &info->space_info;
 659         struct btrfs_space_info *found;
 660
 661         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 662
 663         rcu_read_lock();
 664         list_for_each_entry_rcu(found, head, list) {
 665                 if (found->flags & flags) {
 666                         rcu_read_unlock();
 667                         return found;
 668                 }
 669         }
 670         rcu_read_unlock();
 671         return NULL;
 672 }
 673
 674 /*
 675  * after adding space to the filesystem, we need to clear the full flags
 676  * on all the space infos.
 677  */
 678 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 679 {
 680         struct list_head *head = &info->space_info;
 681         struct btrfs_space_info *found;
 682
 683         rcu_read_lock();
 684         list_for_each_entry_rcu(found, head, list)
 685                 found->full = 0;
 686         rcu_read_unlock();
 687 }
 688
 689 /* simple helper to search for an existing extent at a given offset */
 690 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 691 {
 692         int ret;
 693         struct btrfs_key key;
 694         struct btrfs_path *path;
 695
 696         path = btrfs_alloc_path();
 697         if (!path)
 698                 return -ENOMEM;
 699
 700         key.objectid = start;
 701         key.offset = len;
 702         key.type = BTRFS_EXTENT_ITEM_KEY;
 703         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 704                                 0, 0);
 705         if (ret > 0) {
 706                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 707                 if (key.objectid == start &&
 708                     key.type == BTRFS_METADATA_ITEM_KEY)
 709                         ret = 0;
 710         }
 711         btrfs_free_path(path);
 712         return ret;
 713 }
 714
 715 /*
 716  * helper function to lookup reference count and flags of a tree block.
 717  *
 718  * the head node for delayed ref is used to store the sum of all the
 719  * reference count modifications queued up in the rbtree. the head
 720  * node may also store the extent flags to set. This way you can check
 721  * to see what the reference count and extent flags would be if all of
 722  * the delayed refs are not processed.
 723  */
 724 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 725                              struct btrfs_root *root, u64 bytenr,
 726                              u64 offset, int metadata, u64 *refs, u64 *flags)
 727 {
 728         struct btrfs_delayed_ref_head *head;
 729         struct btrfs_delayed_ref_root *delayed_refs;
 730         struct btrfs_path *path;
 731         struct btrfs_extent_item *ei;
 732         struct extent_buffer *leaf;
 733         struct btrfs_key key;
 734         u32 item_size;
 735         u64 num_refs;
 736         u64 extent_flags;
 737         int ret;
 738
 739         /*
 740          * If we don't have skinny metadata, don't bother doing anything
 741          * different
 742          */
 743         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 744                 offset = root->leafsize;
 745                 metadata = 0;
 746         }
 747
 748         path = btrfs_alloc_path();
 749         if (!path)
 750                 return -ENOMEM;
 751
 752         if (metadata) {
 753                 key.objectid = bytenr;
 754                 key.type = BTRFS_METADATA_ITEM_KEY;
 755                 key.offset = offset;
 756         } else {
 757                 key.objectid = bytenr;
 758                 key.type = BTRFS_EXTENT_ITEM_KEY;
 759                 key.offset = offset;
 760         }
 761
 762         if (!trans) {
 763                 path->skip_locking = 1;
 764                 path->search_commit_root = 1;
 765         }
 766 again:
 767         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 768                                 &key, path, 0, 0);
 769         if (ret < 0)
 770                 goto out_free;
 771
 772         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 773                 key.type = BTRFS_EXTENT_ITEM_KEY;
 774                 key.offset = root->leafsize;
 775                 btrfs_release_path(path);
 776                 goto again;
 777         }
 778
 779         if (ret == 0) {
 780                 leaf = path->nodes[0];
 781                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 782                 if (item_size >= sizeof(*ei)) {
 783                         ei = btrfs_item_ptr(leaf, path->slots[0],
 784                                             struct btrfs_extent_item);
 785                         num_refs = btrfs_extent_refs(leaf, ei);
 786                         extent_flags = btrfs_extent_flags(leaf, ei);
 787                 } else {
 788 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 789                         struct btrfs_extent_item_v0 *ei0;
 790                         BUG_ON(item_size != sizeof(*ei0));
 791                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 792                                              struct btrfs_extent_item_v0);
 793                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 794                         /* FIXME: this isn't correct for data */
 795                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 796 #else
 797                         BUG();
 798 #endif
 799                 }
 800                 BUG_ON(num_refs == 0);
 801         } else {
 802                 num_refs = 0;
 803                 extent_flags = 0;
 804                 ret = 0;
 805         }
 806
 807         if (!trans)
 808                 goto out;
 809
 810         delayed_refs = &trans->transaction->delayed_refs;
 811         spin_lock(&delayed_refs->lock);
 812         head = btrfs_find_delayed_ref_head(trans, bytenr);
 813         if (head) {
 814                 if (!mutex_trylock(&head->mutex)) {
 815                         atomic_inc(&head->node.refs);
 816                         spin_unlock(&delayed_refs->lock);
 817
 818                         btrfs_release_path(path);
 819
 820                         /*
 821                          * Mutex was contended, block until it's released and try
 822                          * again
 823                          */
 824                         mutex_lock(&head->mutex);
 825                         mutex_unlock(&head->mutex);
 826                         btrfs_put_delayed_ref(&head->node);
 827                         goto again;
 828                 }
 829                 if (head->extent_op && head->extent_op->update_flags)
 830                         extent_flags |= head->extent_op->flags_to_set;
 831                 else
 832                         BUG_ON(num_refs == 0);
 833
 834                 num_refs += head->node.ref_mod;
 835                 mutex_unlock(&head->mutex);
 836         }
 837         spin_unlock(&delayed_refs->lock);
 838 out:
 839         WARN_ON(num_refs == 0);
 840         if (refs)
 841                 *refs = num_refs;
 842         if (flags)
 843                 *flags = extent_flags;
 844 out_free:
 845         btrfs_free_path(path);
 846         return ret;
 847 }
 848
 849 /*
 850  * Back reference rules.  Back refs have three main goals:
 851  *
 852  * 1) differentiate between all holders of references to an extent so that
 853  *    when a reference is dropped we can make sure it was a valid reference
 854  *    before freeing the extent.
 855  *
 856  * 2) Provide enough information to quickly find the holders of an extent
 857  *    if we notice a given block is corrupted or bad.
 858  *
 859  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 860  *    maintenance.  This is actually the same as #2, but with a slightly
 861  *    different use case.
 862  *
 863  * There are two kinds of back refs. The implicit back refs is optimized
 864  * for pointers in non-shared tree blocks. For a given pointer in a block,
 865  * back refs of this kind provide information about the block's owner tree
 866  * and the pointer's key. These information allow us to find the block by
 867  * b-tree searching. The full back refs is for pointers in tree blocks not
 868  * referenced by their owner trees. The location of tree block is recorded
 869  * in the back refs. Actually the full back refs is generic, and can be
 870  * used in all cases the implicit back refs is used. The major shortcoming
 871  * of the full back refs is its overhead. Every time a tree block gets
 872  * COWed, we have to update back refs entry for all pointers in it.
 873  *
 874  * For a newly allocated tree block, we use implicit back refs for
 875  * pointers in it. This means most tree related operations only involve
 876  * implicit back refs. For a tree block created in old transaction, the
 877  * only way to drop a reference to it is COW it. So we can detect the
 878  * event that tree block loses its owner tree's reference and do the
 879  * back refs conversion.
 880  *
 881  * When a tree block is COW'd through a tree, there are four cases:
 882  *
 883  * The reference count of the block is one and the tree is the block's
 884  * owner tree. Nothing to do in this case.
 885  *
 886  * The reference count of the block is one and the tree is not the
 887  * block's owner tree. In this case, full back refs is used for pointers
 888  * in the block. Remove these full back refs, add implicit back refs for
 889  * every pointers in the new block.
 890  *
 891  * The reference count of the block is greater than one and the tree is
 892  * the block's owner tree. In this case, implicit back refs is used for
 893  * pointers in the block. Add full back refs for every pointers in the
 894  * block, increase lower level extents' reference counts. The original
 895  * implicit back refs are entailed to the new block.
 896  *
 897  * The reference count of the block is greater than one and the tree is
 898  * not the block's owner tree. Add implicit back refs for every pointer in
 899  * the new block, increase lower level extents' reference count.
 900  *
 901  * Back Reference Key composing:
 902  *
 903  * The key objectid corresponds to the first byte in the extent,
 904  * The key type is used to differentiate between types of back refs.
 905  * There are different meanings of the key offset for different types
 906  * of back refs.
 907  *
 908  * File extents can be referenced by:
 909  *
 910  * - multiple snapshots, subvolumes, or different generations in one subvol
 911  * - different files inside a single subvolume
 912  * - different offsets inside a file (bookend extents in file.c)
 913  *
 914  * The extent ref structure for the implicit back refs has fields for:
 915  *
 916  * - Objectid of the subvolume root
 917  * - objectid of the file holding the reference
 918  * - original offset in the file
 919  * - how many bookend extents
 920  *
 921  * The key offset for the implicit back refs is hash of the first
 922  * three fields.
 923  *
 924  * The extent ref structure for the full back refs has field for:
 925  *
 926  * - number of pointers in the tree leaf
 927  *
 928  * The key offset for the implicit back refs is the first byte of
 929  * the tree leaf
 930  *
 931  * When a file extent is allocated, The implicit back refs is used.
 932  * the fields are filled in:
 933  *
 934  *     (root_key.objectid, inode objectid, offset in file, 1)
 935  *
 936  * When a file extent is removed file truncation, we find the
 937  * corresponding implicit back refs and check the following fields:
 938  *
 939  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 940  *
 941  * Btree extents can be referenced by:
 942  *
 943  * - Different subvolumes
 944  *
 945  * Both the implicit back refs and the full back refs for tree blocks
 946  * only consist of key. The key offset for the implicit back refs is
 947  * objectid of block's owner tree. The key offset for the full back refs
 948  * is the first byte of parent block.
 949  *
 950  * When implicit back refs is used, information about the lowest key and
 951  * level of the tree block are required. These information are stored in
 952  * tree block info structure.
 953  */
 954
 955 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 956 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 957                                   struct btrfs_root *root,
 958                                   struct btrfs_path *path,
 959                                   u64 owner, u32 extra_size)
 960 {
 961         struct btrfs_extent_item *item;
 962         struct btrfs_extent_item_v0 *ei0;
 963         struct btrfs_extent_ref_v0 *ref0;
 964         struct btrfs_tree_block_info *bi;
 965         struct extent_buffer *leaf;
 966         struct btrfs_key key;
 967         struct btrfs_key found_key;
 968         u32 new_size = sizeof(*item);
 969         u64 refs;
 970         int ret;
 971
 972         leaf = path->nodes[0];
 973         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 974
 975         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 976         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 977                              struct btrfs_extent_item_v0);
 978         refs = btrfs_extent_refs_v0(leaf, ei0);
 979
 980         if (owner == (u64)-1) {
 981                 while (1) {
 982                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 983                                 ret = btrfs_next_leaf(root, path);
 984                                 if (ret < 0)
 985                                         return ret;
 986                                 BUG_ON(ret > 0); /* Corruption */
 987                                 leaf = path->nodes[0];
 988                         }
 989                         btrfs_item_key_to_cpu(leaf, &found_key,
 990                                               path->slots[0]);
 991                         BUG_ON(key.objectid != found_key.objectid);
 992                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 993                                 path->slots[0]++;
 994                                 continue;
 995                         }
 996                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 997                                               struct btrfs_extent_ref_v0);
 998                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 999                         break;
1000                 }
1001         }
1002         btrfs_release_path(path);
1003
1004         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1005                 new_size += sizeof(*bi);
1006
1007         new_size -= sizeof(*ei0);
1008         ret = btrfs_search_slot(trans, root, &key, path,
1009                                 new_size + extra_size, 1);
1010         if (ret < 0)
1011                 return ret;
1012         BUG_ON(ret); /* Corruption */
1013
1014         btrfs_extend_item(root, path, new_size);
1015
1016         leaf = path->nodes[0];
1017         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1018         btrfs_set_extent_refs(leaf, item, refs);
1019         /* FIXME: get real generation */
1020         btrfs_set_extent_generation(leaf, item, 0);
1021         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1022                 btrfs_set_extent_flags(leaf, item,
1023                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1024                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1025                 bi = (struct btrfs_tree_block_info *)(item + 1);
1026                 /* FIXME: get first key of the block */
1027                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1028                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1029         } else {
1030                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1031         }
1032         btrfs_mark_buffer_dirty(leaf);
1033         return 0;
1034 }
1035 #endif
1036
1037 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1038 {
1039         u32 high_crc = ~(u32)0;
1040         u32 low_crc = ~(u32)0;
1041         __le64 lenum;
1042
1043         lenum = cpu_to_le64(root_objectid);
1044         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1045         lenum = cpu_to_le64(owner);
1046         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1047         lenum = cpu_to_le64(offset);
1048         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1049
1050         return ((u64)high_crc << 31) ^ (u64)low_crc;
1051 }
1052
1053 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1054                                      struct btrfs_extent_data_ref *ref)
1055 {
1056         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1057                                     btrfs_extent_data_ref_objectid(leaf, ref),
1058                                     btrfs_extent_data_ref_offset(leaf, ref));
1059 }
1060
1061 static int match_extent_data_ref(struct extent_buffer *leaf,
1062                                  struct btrfs_extent_data_ref *ref,
1063                                  u64 root_objectid, u64 owner, u64 offset)
1064 {
1065         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1066             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1067             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1068                 return 0;
1069         return 1;
1070 }
1071
1072 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1073                                            struct btrfs_root *root,
1074                                            struct btrfs_path *path,
1075                                            u64 bytenr, u64 parent,
1076                                            u64 root_objectid,
1077                                            u64 owner, u64 offset)
1078 {
1079         struct btrfs_key key;
1080         struct btrfs_extent_data_ref *ref;
1081         struct extent_buffer *leaf;
1082         u32 nritems;
1083         int ret;
1084         int recow;
1085         int err = -ENOENT;
1086
1087         key.objectid = bytenr;
1088         if (parent) {
1089                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1090                 key.offset = parent;
1091         } else {
1092                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1093                 key.offset = hash_extent_data_ref(root_objectid,
1094                                                   owner, offset);
1095         }
1096 again:
1097         recow = 0;
1098         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1099         if (ret < 0) {
1100                 err = ret;
1101                 goto fail;
1102         }
1103
1104         if (parent) {
1105                 if (!ret)
1106                         return 0;
1107 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1108                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1109                 btrfs_release_path(path);
1110                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1111                 if (ret < 0) {
1112                         err = ret;
1113                         goto fail;
1114                 }
1115                 if (!ret)
1116                         return 0;
1117 #endif
1118                 goto fail;
1119         }
1120
1121         leaf = path->nodes[0];
1122         nritems = btrfs_header_nritems(leaf);
1123         while (1) {
1124                 if (path->slots[0] >= nritems) {
1125                         ret = btrfs_next_leaf(root, path);
1126                         if (ret < 0)
1127                                 err = ret;
1128                         if (ret)
1129                                 goto fail;
1130
1131                         leaf = path->nodes[0];
1132                         nritems = btrfs_header_nritems(leaf);
1133                         recow = 1;
1134                 }
1135
1136                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1137                 if (key.objectid != bytenr ||
1138                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1139                         goto fail;
1140
1141                 ref = btrfs_item_ptr(leaf, path->slots[0],
1142                                      struct btrfs_extent_data_ref);
1143
1144                 if (match_extent_data_ref(leaf, ref, root_objectid,
1145                                           owner, offset)) {
1146                         if (recow) {
1147                                 btrfs_release_path(path);
1148                                 goto again;
1149                         }
1150                         err = 0;
1151                         break;
1152                 }
1153                 path->slots[0]++;
1154         }
1155 fail:
1156         return err;
1157 }
1158
1159 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1160                                            struct btrfs_root *root,
1161                                            struct btrfs_path *path,
1162                                            u64 bytenr, u64 parent,
1163                                            u64 root_objectid, u64 owner,
1164                                            u64 offset, int refs_to_add)
1165 {
1166         struct btrfs_key key;
1167         struct extent_buffer *leaf;
1168         u32 size;
1169         u32 num_refs;
1170         int ret;
1171
1172         key.objectid = bytenr;
1173         if (parent) {
1174                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1175                 key.offset = parent;
1176                 size = sizeof(struct btrfs_shared_data_ref);
1177         } else {
1178                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1179                 key.offset = hash_extent_data_ref(root_objectid,
1180                                                   owner, offset);
1181                 size = sizeof(struct btrfs_extent_data_ref);
1182         }
1183
1184         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1185         if (ret && ret != -EEXIST)
1186                 goto fail;
1187
1188         leaf = path->nodes[0];
1189         if (parent) {
1190                 struct btrfs_shared_data_ref *ref;
1191                 ref = btrfs_item_ptr(leaf, path->slots[0],
1192                                      struct btrfs_shared_data_ref);
1193                 if (ret == 0) {
1194                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1195                 } else {
1196                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1197                         num_refs += refs_to_add;
1198                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1199                 }
1200         } else {
1201                 struct btrfs_extent_data_ref *ref;
1202                 while (ret == -EEXIST) {
1203                         ref = btrfs_item_ptr(leaf, path->slots[0],
1204                                              struct btrfs_extent_data_ref);
1205                         if (match_extent_data_ref(leaf, ref, root_objectid,
1206                                                   owner, offset))
1207                                 break;
1208                         btrfs_release_path(path);
1209                         key.offset++;
1210                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1211                                                       size);
1212                         if (ret && ret != -EEXIST)
1213                                 goto fail;
1214
1215                         leaf = path->nodes[0];
1216                 }
1217                 ref = btrfs_item_ptr(leaf, path->slots[0],
1218                                      struct btrfs_extent_data_ref);
1219                 if (ret == 0) {
1220                         btrfs_set_extent_data_ref_root(leaf, ref,
1221                                                        root_objectid);
1222                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1223                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1224                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1225                 } else {
1226                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1227                         num_refs += refs_to_add;
1228                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1229                 }
1230         }
1231         btrfs_mark_buffer_dirty(leaf);
1232         ret = 0;
1233 fail:
1234         btrfs_release_path(path);
1235         return ret;
1236 }
1237
1238 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1239                                            struct btrfs_root *root,
1240                                            struct btrfs_path *path,
1241                                            int refs_to_drop)
1242 {
1243         struct btrfs_key key;
1244         struct btrfs_extent_data_ref *ref1 = NULL;
1245         struct btrfs_shared_data_ref *ref2 = NULL;
1246         struct extent_buffer *leaf;
1247         u32 num_refs = 0;
1248         int ret = 0;
1249
1250         leaf = path->nodes[0];
1251         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1252
1253         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1254                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1255                                       struct btrfs_extent_data_ref);
1256                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1257         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1258                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1259                                       struct btrfs_shared_data_ref);
1260                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1261 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1262         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1263                 struct btrfs_extent_ref_v0 *ref0;
1264                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1265                                       struct btrfs_extent_ref_v0);
1266                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1267 #endif
1268         } else {
1269                 BUG();
1270         }
1271
1272         BUG_ON(num_refs < refs_to_drop);
1273         num_refs -= refs_to_drop;
1274
1275         if (num_refs == 0) {
1276                 ret = btrfs_del_item(trans, root, path);
1277         } else {
1278                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1279                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1280                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1281                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1282 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1283                 else {
1284                         struct btrfs_extent_ref_v0 *ref0;
1285                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1286                                         struct btrfs_extent_ref_v0);
1287                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1288                 }
1289 #endif
1290                 btrfs_mark_buffer_dirty(leaf);
1291         }
1292         return ret;
1293 }
1294
1295 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1296                                           struct btrfs_path *path,
1297                                           struct btrfs_extent_inline_ref *iref)
1298 {
1299         struct btrfs_key key;
1300         struct extent_buffer *leaf;
1301         struct btrfs_extent_data_ref *ref1;
1302         struct btrfs_shared_data_ref *ref2;
1303         u32 num_refs = 0;
1304
1305         leaf = path->nodes[0];
1306         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1307         if (iref) {
1308                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1309                     BTRFS_EXTENT_DATA_REF_KEY) {
1310                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1311                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1312                 } else {
1313                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1314                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1315                 }
1316         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1317                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1318                                       struct btrfs_extent_data_ref);
1319                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1320         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1321                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1322                                       struct btrfs_shared_data_ref);
1323                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1324 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1325         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1326                 struct btrfs_extent_ref_v0 *ref0;
1327                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1328                                       struct btrfs_extent_ref_v0);
1329                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1330 #endif
1331         } else {
1332                 WARN_ON(1);
1333         }
1334         return num_refs;
1335 }
1336
1337 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1338                                           struct btrfs_root *root,
1339                                           struct btrfs_path *path,
1340                                           u64 bytenr, u64 parent,
1341                                           u64 root_objectid)
1342 {
1343         struct btrfs_key key;
1344         int ret;
1345
1346         key.objectid = bytenr;
1347         if (parent) {
1348                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1349                 key.offset = parent;
1350         } else {
1351                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1352                 key.offset = root_objectid;
1353         }
1354
1355         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1356         if (ret > 0)
1357                 ret = -ENOENT;
1358 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1359         if (ret == -ENOENT && parent) {
1360                 btrfs_release_path(path);
1361                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1362                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1363                 if (ret > 0)
1364                         ret = -ENOENT;
1365         }
1366 #endif
1367         return ret;
1368 }
1369
1370 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1371                                           struct btrfs_root *root,
1372                                           struct btrfs_path *path,
1373                                           u64 bytenr, u64 parent,
1374                                           u64 root_objectid)
1375 {
1376         struct btrfs_key key;
1377         int ret;
1378
1379         key.objectid = bytenr;
1380         if (parent) {
1381                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1382                 key.offset = parent;
1383         } else {
1384                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1385                 key.offset = root_objectid;
1386         }
1387
1388         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1389         btrfs_release_path(path);
1390         return ret;
1391 }
1392
1393 static inline int extent_ref_type(u64 parent, u64 owner)
1394 {
1395         int type;
1396         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1397                 if (parent > 0)
1398                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1399                 else
1400                         type = BTRFS_TREE_BLOCK_REF_KEY;
1401         } else {
1402                 if (parent > 0)
1403                         type = BTRFS_SHARED_DATA_REF_KEY;
1404                 else
1405                         type = BTRFS_EXTENT_DATA_REF_KEY;
1406         }
1407         return type;
1408 }
1409
1410 static int find_next_key(struct btrfs_path *path, int level,
1411                          struct btrfs_key *key)
1412
1413 {
1414         for (; level < BTRFS_MAX_LEVEL; level++) {
1415                 if (!path->nodes[level])
1416                         break;
1417                 if (path->slots[level] + 1 >=
1418                     btrfs_header_nritems(path->nodes[level]))
1419                         continue;
1420                 if (level == 0)
1421                         btrfs_item_key_to_cpu(path->nodes[level], key,
1422                                               path->slots[level] + 1);
1423                 else
1424                         btrfs_node_key_to_cpu(path->nodes[level], key,
1425                                               path->slots[level] + 1);
1426                 return 0;
1427         }
1428         return 1;
1429 }
1430
1431 /*
1432  * look for inline back ref. if back ref is found, *ref_ret is set
1433  * to the address of inline back ref, and 0 is returned.
1434  *
1435  * if back ref isn't found, *ref_ret is set to the address where it
1436  * should be inserted, and -ENOENT is returned.
1437  *
1438  * if insert is true and there are too many inline back refs, the path
1439  * points to the extent item, and -EAGAIN is returned.
1440  *
1441  * NOTE: inline back refs are ordered in the same way that back ref
1442  *       items in the tree are ordered.
1443  */
1444 static noinline_for_stack
1445 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1446                                  struct btrfs_root *root,
1447                                  struct btrfs_path *path,
1448                                  struct btrfs_extent_inline_ref **ref_ret,
1449                                  u64 bytenr, u64 num_bytes,
1450                                  u64 parent, u64 root_objectid,
1451                                  u64 owner, u64 offset, int insert)
1452 {
1453         struct btrfs_key key;
1454         struct extent_buffer *leaf;
1455         struct btrfs_extent_item *ei;
1456         struct btrfs_extent_inline_ref *iref;
1457         u64 flags;
1458         u64 item_size;
1459         unsigned long ptr;
1460         unsigned long end;
1461         int extra_size;
1462         int type;
1463         int want;
1464         int ret;
1465         int err = 0;
1466         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1467                                                  SKINNY_METADATA);
1468
1469         key.objectid = bytenr;
1470         key.type = BTRFS_EXTENT_ITEM_KEY;
1471         key.offset = num_bytes;
1472
1473         want = extent_ref_type(parent, owner);
1474         if (insert) {
1475                 extra_size = btrfs_extent_inline_ref_size(want);
1476                 path->keep_locks = 1;
1477         } else
1478                 extra_size = -1;
1479
1480         /*
1481          * Owner is our parent level, so we can just add one to get the level
1482          * for the block we are interested in.
1483          */
1484         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1485                 key.type = BTRFS_METADATA_ITEM_KEY;
1486                 key.offset = owner;
1487         }
1488
1489 again:
1490         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1491         if (ret < 0) {
1492                 err = ret;
1493                 goto out;
1494         }
1495
1496         /*
1497          * We may be a newly converted file system which still has the old fat
1498          * extent entries for metadata, so try and see if we have one of those.
1499          */
1500         if (ret > 0 && skinny_metadata) {
1501                 skinny_metadata = false;
1502                 if (path->slots[0]) {
1503                         path->slots[0]--;
1504                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1505                                               path->slots[0]);
1506                         if (key.objectid == bytenr &&
1507                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1508                             key.offset == num_bytes)
1509                                 ret = 0;
1510                 }
1511                 if (ret) {
1512                         key.type = BTRFS_EXTENT_ITEM_KEY;
1513                         key.offset = num_bytes;
1514                         btrfs_release_path(path);
1515                         goto again;
1516                 }
1517         }
1518
1519         if (ret && !insert) {
1520                 err = -ENOENT;
1521                 goto out;
1522         } else if (ret) {
1523                 err = -EIO;
1524                 WARN_ON(1);
1525                 goto out;
1526         }
1527
1528         leaf = path->nodes[0];
1529         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1530 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1531         if (item_size < sizeof(*ei)) {
1532                 if (!insert) {
1533                         err = -ENOENT;
1534                         goto out;
1535                 }
1536                 ret = convert_extent_item_v0(trans, root, path, owner,
1537                                              extra_size);
1538                 if (ret < 0) {
1539                         err = ret;
1540                         goto out;
1541                 }
1542                 leaf = path->nodes[0];
1543                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1544         }
1545 #endif
1546         BUG_ON(item_size < sizeof(*ei));
1547
1548         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1549         flags = btrfs_extent_flags(leaf, ei);
1550
1551         ptr = (unsigned long)(ei + 1);
1552         end = (unsigned long)ei + item_size;
1553
1554         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1555                 ptr += sizeof(struct btrfs_tree_block_info);
1556                 BUG_ON(ptr > end);
1557         }
1558
1559         err = -ENOENT;
1560         while (1) {
1561                 if (ptr >= end) {
1562                         WARN_ON(ptr > end);
1563                         break;
1564                 }
1565                 iref = (struct btrfs_extent_inline_ref *)ptr;
1566                 type = btrfs_extent_inline_ref_type(leaf, iref);
1567                 if (want < type)
1568                         break;
1569                 if (want > type) {
1570                         ptr += btrfs_extent_inline_ref_size(type);
1571                         continue;
1572                 }
1573
1574                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1575                         struct btrfs_extent_data_ref *dref;
1576                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1577                         if (match_extent_data_ref(leaf, dref, root_objectid,
1578                                                   owner, offset)) {
1579                                 err = 0;
1580                                 break;
1581                         }
1582                         if (hash_extent_data_ref_item(leaf, dref) <
1583                             hash_extent_data_ref(root_objectid, owner, offset))
1584                                 break;
1585                 } else {
1586                         u64 ref_offset;
1587                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1588                         if (parent > 0) {
1589                                 if (parent == ref_offset) {
1590                                         err = 0;
1591                                         break;
1592                                 }
1593                                 if (ref_offset < parent)
1594                                         break;
1595                         } else {
1596                                 if (root_objectid == ref_offset) {
1597                                         err = 0;
1598                                         break;
1599                                 }
1600                                 if (ref_offset < root_objectid)
1601                                         break;
1602                         }
1603                 }
1604                 ptr += btrfs_extent_inline_ref_size(type);
1605         }
1606         if (err == -ENOENT && insert) {
1607                 if (item_size + extra_size >=
1608                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1609                         err = -EAGAIN;
1610                         goto out;
1611                 }
1612                 /*
1613                  * To add new inline back ref, we have to make sure
1614                  * there is no corresponding back ref item.
1615                  * For simplicity, we just do not add new inline back
1616                  * ref if there is any kind of item for this block
1617                  */
1618                 if (find_next_key(path, 0, &key) == 0 &&
1619                     key.objectid == bytenr &&
1620                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1621                         err = -EAGAIN;
1622                         goto out;
1623                 }
1624         }
1625         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1626 out:
1627         if (insert) {
1628                 path->keep_locks = 0;
1629                 btrfs_unlock_up_safe(path, 1);
1630         }
1631         return err;
1632 }
1633
1634 /*
1635  * helper to add new inline back ref
1636  */
1637 static noinline_for_stack
1638 void setup_inline_extent_backref(struct btrfs_root *root,
1639                                  struct btrfs_path *path,
1640                                  struct btrfs_extent_inline_ref *iref,
1641                                  u64 parent, u64 root_objectid,
1642                                  u64 owner, u64 offset, int refs_to_add,
1643                                  struct btrfs_delayed_extent_op *extent_op)
1644 {
1645         struct extent_buffer *leaf;
1646         struct btrfs_extent_item *ei;
1647         unsigned long ptr;
1648         unsigned long end;
1649         unsigned long item_offset;
1650         u64 refs;
1651         int size;
1652         int type;
1653
1654         leaf = path->nodes[0];
1655         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1656         item_offset = (unsigned long)iref - (unsigned long)ei;
1657
1658         type = extent_ref_type(parent, owner);
1659         size = btrfs_extent_inline_ref_size(type);
1660
1661         btrfs_extend_item(root, path, size);
1662
1663         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1664         refs = btrfs_extent_refs(leaf, ei);
1665         refs += refs_to_add;
1666         btrfs_set_extent_refs(leaf, ei, refs);
1667         if (extent_op)
1668                 __run_delayed_extent_op(extent_op, leaf, ei);
1669
1670         ptr = (unsigned long)ei + item_offset;
1671         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1672         if (ptr < end - size)
1673                 memmove_extent_buffer(leaf, ptr + size, ptr,
1674                                       end - size - ptr);
1675
1676         iref = (struct btrfs_extent_inline_ref *)ptr;
1677         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1678         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1679                 struct btrfs_extent_data_ref *dref;
1680                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1681                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1682                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1683                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1684                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1685         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1686                 struct btrfs_shared_data_ref *sref;
1687                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1688                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1689                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1690         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1691                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1692         } else {
1693                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1694         }
1695         btrfs_mark_buffer_dirty(leaf);
1696 }
1697
1698 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1699                                  struct btrfs_root *root,
1700                                  struct btrfs_path *path,
1701                                  struct btrfs_extent_inline_ref **ref_ret,
1702                                  u64 bytenr, u64 num_bytes, u64 parent,
1703                                  u64 root_objectid, u64 owner, u64 offset)
1704 {
1705         int ret;
1706
1707         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1708                                            bytenr, num_bytes, parent,
1709                                            root_objectid, owner, offset, 0);
1710         if (ret != -ENOENT)
1711                 return ret;
1712
1713         btrfs_release_path(path);
1714         *ref_ret = NULL;
1715
1716         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1717                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1718                                             root_objectid);
1719         } else {
1720                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1721                                              root_objectid, owner, offset);
1722         }
1723         return ret;
1724 }
1725
1726 /*
1727  * helper to update/remove inline back ref
1728  */
1729 static noinline_for_stack
1730 void update_inline_extent_backref(struct btrfs_root *root,
1731                                   struct btrfs_path *path,
1732                                   struct btrfs_extent_inline_ref *iref,
1733                                   int refs_to_mod,
1734                                   struct btrfs_delayed_extent_op *extent_op)
1735 {
1736         struct extent_buffer *leaf;
1737         struct btrfs_extent_item *ei;
1738         struct btrfs_extent_data_ref *dref = NULL;
1739         struct btrfs_shared_data_ref *sref = NULL;
1740         unsigned long ptr;
1741         unsigned long end;
1742         u32 item_size;
1743         int size;
1744         int type;
1745         u64 refs;
1746
1747         leaf = path->nodes[0];
1748         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1749         refs = btrfs_extent_refs(leaf, ei);
1750         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1751         refs += refs_to_mod;
1752         btrfs_set_extent_refs(leaf, ei, refs);
1753         if (extent_op)
1754                 __run_delayed_extent_op(extent_op, leaf, ei);
1755
1756         type = btrfs_extent_inline_ref_type(leaf, iref);
1757
1758         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1759                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1760                 refs = btrfs_extent_data_ref_count(leaf, dref);
1761         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1762                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1763                 refs = btrfs_shared_data_ref_count(leaf, sref);
1764         } else {
1765                 refs = 1;
1766                 BUG_ON(refs_to_mod != -1);
1767         }
1768
1769         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1770         refs += refs_to_mod;
1771
1772         if (refs > 0) {
1773                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1774                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1775                 else
1776                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1777         } else {
1778                 size =  btrfs_extent_inline_ref_size(type);
1779                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1780                 ptr = (unsigned long)iref;
1781                 end = (unsigned long)ei + item_size;
1782                 if (ptr + size < end)
1783                         memmove_extent_buffer(leaf, ptr, ptr + size,
1784                                               end - ptr - size);
1785                 item_size -= size;
1786                 btrfs_truncate_item(root, path, item_size, 1);
1787         }
1788         btrfs_mark_buffer_dirty(leaf);
1789 }
1790
1791 static noinline_for_stack
1792 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1793                                  struct btrfs_root *root,
1794                                  struct btrfs_path *path,
1795                                  u64 bytenr, u64 num_bytes, u64 parent,
1796                                  u64 root_objectid, u64 owner,
1797                                  u64 offset, int refs_to_add,
1798                                  struct btrfs_delayed_extent_op *extent_op)
1799 {
1800         struct btrfs_extent_inline_ref *iref;
1801         int ret;
1802
1803         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1804                                            bytenr, num_bytes, parent,
1805                                            root_objectid, owner, offset, 1);
1806         if (ret == 0) {
1807                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1808                 update_inline_extent_backref(root, path, iref,
1809                                              refs_to_add, extent_op);
1810         } else if (ret == -ENOENT) {
1811                 setup_inline_extent_backref(root, path, iref, parent,
1812                                             root_objectid, owner, offset,
1813                                             refs_to_add, extent_op);
1814                 ret = 0;
1815         }
1816         return ret;
1817 }
1818
1819 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1820                                  struct btrfs_root *root,
1821                                  struct btrfs_path *path,
1822                                  u64 bytenr, u64 parent, u64 root_objectid,
1823                                  u64 owner, u64 offset, int refs_to_add)
1824 {
1825         int ret;
1826         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1827                 BUG_ON(refs_to_add != 1);
1828                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1829                                             parent, root_objectid);
1830         } else {
1831                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1832                                              parent, root_objectid,
1833                                              owner, offset, refs_to_add);
1834         }
1835         return ret;
1836 }
1837
1838 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1839                                  struct btrfs_root *root,
1840                                  struct btrfs_path *path,
1841                                  struct btrfs_extent_inline_ref *iref,
1842                                  int refs_to_drop, int is_data)
1843 {
1844         int ret = 0;
1845
1846         BUG_ON(!is_data && refs_to_drop != 1);
1847         if (iref) {
1848                 update_inline_extent_backref(root, path, iref,
1849                                              -refs_to_drop, NULL);
1850         } else if (is_data) {
1851                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1852         } else {
1853                 ret = btrfs_del_item(trans, root, path);
1854         }
1855         return ret;
1856 }
1857
1858 static int btrfs_issue_discard(struct block_device *bdev,
1859                                 u64 start, u64 len)
1860 {
1861         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1862 }
1863
1864 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1865                                 u64 num_bytes, u64 *actual_bytes)
1866 {
1867         int ret;
1868         u64 discarded_bytes = 0;
1869         struct btrfs_bio *bbio = NULL;
1870
1871
1872         /* Tell the block device(s) that the sectors can be discarded */
1873         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1874                               bytenr, &num_bytes, &bbio, 0);
1875         /* Error condition is -ENOMEM */
1876         if (!ret) {
1877                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1878                 int i;
1879
1880
1881                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1882                         if (!stripe->dev->can_discard)
1883                                 continue;
1884
1885                         ret = btrfs_issue_discard(stripe->dev->bdev,
1886                                                   stripe->physical,
1887                                                   stripe->length);
1888                         if (!ret)
1889                                 discarded_bytes += stripe->length;
1890                         else if (ret != -EOPNOTSUPP)
1891                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1892
1893                         /*
1894                          * Just in case we get back EOPNOTSUPP for some reason,
1895                          * just ignore the return value so we don't screw up
1896                          * people calling discard_extent.
1897                          */
1898                         ret = 0;
1899                 }
1900                 kfree(bbio);
1901         }
1902
1903         if (actual_bytes)
1904                 *actual_bytes = discarded_bytes;
1905
1906
1907         if (ret == -EOPNOTSUPP)
1908                 ret = 0;
1909         return ret;
1910 }
1911
1912 /* Can return -ENOMEM */
1913 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1914                          struct btrfs_root *root,
1915                          u64 bytenr, u64 num_bytes, u64 parent,
1916                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1917 {
1918         int ret;
1919         struct btrfs_fs_info *fs_info = root->fs_info;
1920
1921         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1922                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1923
1924         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1925                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1926                                         num_bytes,
1927                                         parent, root_objectid, (int)owner,
1928                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1929         } else {
1930                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1931                                         num_bytes,
1932                                         parent, root_objectid, owner, offset,
1933                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1934         }
1935         return ret;
1936 }
1937
1938 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1939                                   struct btrfs_root *root,
1940                                   u64 bytenr, u64 num_bytes,
1941                                   u64 parent, u64 root_objectid,
1942                                   u64 owner, u64 offset, int refs_to_add,
1943                                   struct btrfs_delayed_extent_op *extent_op)
1944 {
1945         struct btrfs_path *path;
1946         struct extent_buffer *leaf;
1947         struct btrfs_extent_item *item;
1948         u64 refs;
1949         int ret;
1950         int err = 0;
1951
1952         path = btrfs_alloc_path();
1953         if (!path)
1954                 return -ENOMEM;
1955
1956         path->reada = 1;
1957         path->leave_spinning = 1;
1958         /* this will setup the path even if it fails to insert the back ref */
1959         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1960                                            path, bytenr, num_bytes, parent,
1961                                            root_objectid, owner, offset,
1962                                            refs_to_add, extent_op);
1963         if (ret == 0)
1964                 goto out;
1965
1966         if (ret != -EAGAIN) {
1967                 err = ret;
1968                 goto out;
1969         }
1970
1971         leaf = path->nodes[0];
1972         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1973         refs = btrfs_extent_refs(leaf, item);
1974         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1975         if (extent_op)
1976                 __run_delayed_extent_op(extent_op, leaf, item);
1977
1978         btrfs_mark_buffer_dirty(leaf);
1979         btrfs_release_path(path);
1980
1981         path->reada = 1;
1982         path->leave_spinning = 1;
1983
1984         /* now insert the actual backref */
1985         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1986                                     path, bytenr, parent, root_objectid,
1987                                     owner, offset, refs_to_add);
1988         if (ret)
1989                 btrfs_abort_transaction(trans, root, ret);
1990 out:
1991         btrfs_free_path(path);
1992         return err;
1993 }
1994
1995 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1996                                 struct btrfs_root *root,
1997                                 struct btrfs_delayed_ref_node *node,
1998                                 struct btrfs_delayed_extent_op *extent_op,
1999                                 int insert_reserved)
2000 {
2001         int ret = 0;
2002         struct btrfs_delayed_data_ref *ref;
2003         struct btrfs_key ins;
2004         u64 parent = 0;
2005         u64 ref_root = 0;
2006         u64 flags = 0;
2007
2008         ins.objectid = node->bytenr;
2009         ins.offset = node->num_bytes;
2010         ins.type = BTRFS_EXTENT_ITEM_KEY;
2011
2012         ref = btrfs_delayed_node_to_data_ref(node);
2013         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2014                 parent = ref->parent;
2015         else
2016                 ref_root = ref->root;
2017
2018         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2019                 if (extent_op)
2020                         flags |= extent_op->flags_to_set;
2021                 ret = alloc_reserved_file_extent(trans, root,
2022                                                  parent, ref_root, flags,
2023                                                  ref->objectid, ref->offset,
2024                                                  &ins, node->ref_mod);
2025         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2026                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2027                                              node->num_bytes, parent,
2028                                              ref_root, ref->objectid,
2029                                              ref->offset, node->ref_mod,
2030                                              extent_op);
2031         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2032                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2033                                           node->num_bytes, parent,
2034                                           ref_root, ref->objectid,
2035                                           ref->offset, node->ref_mod,
2036                                           extent_op);
2037         } else {
2038                 BUG();
2039         }
2040         return ret;
2041 }
2042
2043 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2044                                     struct extent_buffer *leaf,
2045                                     struct btrfs_extent_item *ei)
2046 {
2047         u64 flags = btrfs_extent_flags(leaf, ei);
2048         if (extent_op->update_flags) {
2049                 flags |= extent_op->flags_to_set;
2050                 btrfs_set_extent_flags(leaf, ei, flags);
2051         }
2052
2053         if (extent_op->update_key) {
2054                 struct btrfs_tree_block_info *bi;
2055                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2056                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2057                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2058         }
2059 }
2060
2061 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2062                                  struct btrfs_root *root,
2063                                  struct btrfs_delayed_ref_node *node,
2064                                  struct btrfs_delayed_extent_op *extent_op)
2065 {
2066         struct btrfs_key key;
2067         struct btrfs_path *path;
2068         struct btrfs_extent_item *ei;
2069         struct extent_buffer *leaf;
2070         u32 item_size;
2071         int ret;
2072         int err = 0;
2073         int metadata = !extent_op->is_data;
2074
2075         if (trans->aborted)
2076                 return 0;
2077
2078         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2079                 metadata = 0;
2080
2081         path = btrfs_alloc_path();
2082         if (!path)
2083                 return -ENOMEM;
2084
2085         key.objectid = node->bytenr;
2086
2087         if (metadata) {
2088                 key.type = BTRFS_METADATA_ITEM_KEY;
2089                 key.offset = extent_op->level;
2090         } else {
2091                 key.type = BTRFS_EXTENT_ITEM_KEY;
2092                 key.offset = node->num_bytes;
2093         }
2094
2095 again:
2096         path->reada = 1;
2097         path->leave_spinning = 1;
2098         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2099                                 path, 0, 1);
2100         if (ret < 0) {
2101                 err = ret;
2102                 goto out;
2103         }
2104         if (ret > 0) {
2105                 if (metadata) {
2106                         btrfs_release_path(path);
2107                         metadata = 0;
2108
2109                         key.offset = node->num_bytes;
2110                         key.type = BTRFS_EXTENT_ITEM_KEY;
2111                         goto again;
2112                 }
2113                 err = -EIO;
2114                 goto out;
2115         }
2116
2117         leaf = path->nodes[0];
2118         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2119 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2120         if (item_size < sizeof(*ei)) {
2121                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2122                                              path, (u64)-1, 0);
2123                 if (ret < 0) {
2124                         err = ret;
2125                         goto out;
2126                 }
2127                 leaf = path->nodes[0];
2128                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2129         }
2130 #endif
2131         BUG_ON(item_size < sizeof(*ei));
2132         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2133         __run_delayed_extent_op(extent_op, leaf, ei);
2134
2135         btrfs_mark_buffer_dirty(leaf);
2136 out:
2137         btrfs_free_path(path);
2138         return err;
2139 }
2140
2141 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2142                                 struct btrfs_root *root,
2143                                 struct btrfs_delayed_ref_node *node,
2144                                 struct btrfs_delayed_extent_op *extent_op,
2145                                 int insert_reserved)
2146 {
2147         int ret = 0;
2148         struct btrfs_delayed_tree_ref *ref;
2149         struct btrfs_key ins;
2150         u64 parent = 0;
2151         u64 ref_root = 0;
2152         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2153                                                  SKINNY_METADATA);
2154
2155         ref = btrfs_delayed_node_to_tree_ref(node);
2156         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2157                 parent = ref->parent;
2158         else
2159                 ref_root = ref->root;
2160
2161         ins.objectid = node->bytenr;
2162         if (skinny_metadata) {
2163                 ins.offset = ref->level;
2164                 ins.type = BTRFS_METADATA_ITEM_KEY;
2165         } else {
2166                 ins.offset = node->num_bytes;
2167                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2168         }
2169
2170         BUG_ON(node->ref_mod != 1);
2171         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2172                 BUG_ON(!extent_op || !extent_op->update_flags);
2173                 ret = alloc_reserved_tree_block(trans, root,
2174                                                 parent, ref_root,
2175                                                 extent_op->flags_to_set,
2176                                                 &extent_op->key,
2177                                                 ref->level, &ins);
2178         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2179                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2180                                              node->num_bytes, parent, ref_root,
2181                                              ref->level, 0, 1, extent_op);
2182         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2183                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2184                                           node->num_bytes, parent, ref_root,
2185                                           ref->level, 0, 1, extent_op);
2186         } else {
2187                 BUG();
2188         }
2189         return ret;
2190 }
2191
2192 /* helper function to actually process a single delayed ref entry */
2193 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2194                                struct btrfs_root *root,
2195                                struct btrfs_delayed_ref_node *node,
2196                                struct btrfs_delayed_extent_op *extent_op,
2197                                int insert_reserved)
2198 {
2199         int ret = 0;
2200
2201         if (trans->aborted)
2202                 return 0;
2203
2204         if (btrfs_delayed_ref_is_head(node)) {
2205                 struct btrfs_delayed_ref_head *head;
2206                 /*
2207                  * we've hit the end of the chain and we were supposed
2208                  * to insert this extent into the tree.  But, it got
2209                  * deleted before we ever needed to insert it, so all
2210                  * we have to do is clean up the accounting
2211                  */
2212                 BUG_ON(extent_op);
2213                 head = btrfs_delayed_node_to_head(node);
2214                 if (insert_reserved) {
2215                         btrfs_pin_extent(root, node->bytenr,
2216                                          node->num_bytes, 1);
2217                         if (head->is_data) {
2218                                 ret = btrfs_del_csums(trans, root,
2219                                                       node->bytenr,
2220                                                       node->num_bytes);
2221                         }
2222                 }
2223                 return ret;
2224         }
2225
2226         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2227             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2228                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2229                                            insert_reserved);
2230         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2231                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2232                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2233                                            insert_reserved);
2234         else
2235                 BUG();
2236         return ret;
2237 }
2238
2239 static noinline struct btrfs_delayed_ref_node *
2240 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2241 {
2242         struct rb_node *node;
2243         struct btrfs_delayed_ref_node *ref;
2244         int action = BTRFS_ADD_DELAYED_REF;
2245 again:
2246         /*
2247          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2248          * this prevents ref count from going down to zero when
2249          * there still are pending delayed ref.
2250          */
2251         node = rb_prev(&head->node.rb_node);
2252         while (1) {
2253                 if (!node)
2254                         break;
2255                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2256                                 rb_node);
2257                 if (ref->bytenr != head->node.bytenr)
2258                         break;
2259                 if (ref->action == action)
2260                         return ref;
2261                 node = rb_prev(node);
2262         }
2263         if (action == BTRFS_ADD_DELAYED_REF) {
2264                 action = BTRFS_DROP_DELAYED_REF;
2265                 goto again;
2266         }
2267         return NULL;
2268 }
2269
2270 /*
2271  * Returns 0 on success or if called with an already aborted transaction.
2272  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2273  */
2274 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2275                                        struct btrfs_root *root,
2276                                        struct list_head *cluster)
2277 {
2278         struct btrfs_delayed_ref_root *delayed_refs;
2279         struct btrfs_delayed_ref_node *ref;
2280         struct btrfs_delayed_ref_head *locked_ref = NULL;
2281         struct btrfs_delayed_extent_op *extent_op;
2282         struct btrfs_fs_info *fs_info = root->fs_info;
2283         int ret;
2284         int count = 0;
2285         int must_insert_reserved = 0;
2286
2287         delayed_refs = &trans->transaction->delayed_refs;
2288         while (1) {
2289                 if (!locked_ref) {
2290                         /* pick a new head ref from the cluster list */
2291                         if (list_empty(cluster))
2292                                 break;
2293
2294                         locked_ref = list_entry(cluster->next,
2295                                      struct btrfs_delayed_ref_head, cluster);
2296
2297                         /* grab the lock that says we are going to process
2298                          * all the refs for this head */
2299                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2300
2301                         /*
2302                          * we may have dropped the spin lock to get the head
2303                          * mutex lock, and that might have given someone else
2304                          * time to free the head.  If that's true, it has been
2305                          * removed from our list and we can move on.
2306                          */
2307                         if (ret == -EAGAIN) {
2308                                 locked_ref = NULL;
2309                                 count++;
2310                                 continue;
2311                         }
2312                 }
2313
2314                 /*
2315                  * We need to try and merge add/drops of the same ref since we
2316                  * can run into issues with relocate dropping the implicit ref
2317                  * and then it being added back again before the drop can
2318                  * finish.  If we merged anything we need to re-loop so we can
2319                  * get a good ref.
2320                  */
2321                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2322                                          locked_ref);
2323
2324                 /*
2325                  * locked_ref is the head node, so we have to go one
2326                  * node back for any delayed ref updates
2327                  */
2328                 ref = select_delayed_ref(locked_ref);
2329
2330                 if (ref && ref->seq &&
2331                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2332                         /*
2333                          * there are still refs with lower seq numbers in the
2334                          * process of being added. Don't run this ref yet.
2335                          */
2336                         list_del_init(&locked_ref->cluster);
2337                         btrfs_delayed_ref_unlock(locked_ref);
2338                         locked_ref = NULL;
2339                         delayed_refs->num_heads_ready++;
2340                         spin_unlock(&delayed_refs->lock);
2341                         cond_resched();
2342                         spin_lock(&delayed_refs->lock);
2343                         continue;
2344                 }
2345
2346                 /*
2347                  * record the must insert reserved flag before we
2348                  * drop the spin lock.
2349                  */
2350                 must_insert_reserved = locked_ref->must_insert_reserved;
2351                 locked_ref->must_insert_reserved = 0;
2352
2353                 extent_op = locked_ref->extent_op;
2354                 locked_ref->extent_op = NULL;
2355
2356                 if (!ref) {
2357                         /* All delayed refs have been processed, Go ahead
2358                          * and send the head node to run_one_delayed_ref,
2359                          * so that any accounting fixes can happen
2360                          */
2361                         ref = &locked_ref->node;
2362
2363                         if (extent_op && must_insert_reserved) {
2364                                 btrfs_free_delayed_extent_op(extent_op);
2365                                 extent_op = NULL;
2366                         }
2367
2368                         if (extent_op) {
2369                                 spin_unlock(&delayed_refs->lock);
2370
2371                                 ret = run_delayed_extent_op(trans, root,
2372                                                             ref, extent_op);
2373                                 btrfs_free_delayed_extent_op(extent_op);
2374
2375                                 if (ret) {
2376                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2377                                         spin_lock(&delayed_refs->lock);
2378                                         btrfs_delayed_ref_unlock(locked_ref);
2379                                         return ret;
2380                                 }
2381
2382                                 goto next;
2383                         }
2384                 }
2385
2386                 ref->in_tree = 0;
2387                 rb_erase(&ref->rb_node, &delayed_refs->root);
2388                 delayed_refs->num_entries--;
2389                 if (!btrfs_delayed_ref_is_head(ref)) {
2390                         /*
2391                          * when we play the delayed ref, also correct the
2392                          * ref_mod on head
2393                          */
2394                         switch (ref->action) {
2395                         case BTRFS_ADD_DELAYED_REF:
2396                         case BTRFS_ADD_DELAYED_EXTENT:
2397                                 locked_ref->node.ref_mod -= ref->ref_mod;
2398                                 break;
2399                         case BTRFS_DROP_DELAYED_REF:
2400                                 locked_ref->node.ref_mod += ref->ref_mod;
2401                                 break;
2402                         default:
2403                                 WARN_ON(1);
2404                         }
2405                 }
2406                 spin_unlock(&delayed_refs->lock);
2407
2408                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2409                                           must_insert_reserved);
2410
2411                 btrfs_free_delayed_extent_op(extent_op);
2412                 if (ret) {
2413                         btrfs_delayed_ref_unlock(locked_ref);
2414                         btrfs_put_delayed_ref(ref);
2415                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2416                         spin_lock(&delayed_refs->lock);
2417                         return ret;
2418                 }
2419
2420                 /*
2421                  * If this node is a head, that means all the refs in this head
2422                  * have been dealt with, and we will pick the next head to deal
2423                  * with, so we must unlock the head and drop it from the cluster
2424                  * list before we release it.
2425                  */
2426                 if (btrfs_delayed_ref_is_head(ref)) {
2427                         list_del_init(&locked_ref->cluster);
2428                         btrfs_delayed_ref_unlock(locked_ref);
2429                         locked_ref = NULL;
2430                 }
2431                 btrfs_put_delayed_ref(ref);
2432                 count++;
2433 next:
2434                 cond_resched();
2435                 spin_lock(&delayed_refs->lock);
2436         }
2437         return count;
2438 }
2439
2440 #ifdef SCRAMBLE_DELAYED_REFS
2441 /*
2442  * Normally delayed refs get processed in ascending bytenr order. This
2443  * correlates in most cases to the order added. To expose dependencies on this
2444  * order, we start to process the tree in the middle instead of the beginning
2445  */
2446 static u64 find_middle(struct rb_root *root)
2447 {
2448         struct rb_node *n = root->rb_node;
2449         struct btrfs_delayed_ref_node *entry;
2450         int alt = 1;
2451         u64 middle;
2452         u64 first = 0, last = 0;
2453
2454         n = rb_first(root);
2455         if (n) {
2456                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2457                 first = entry->bytenr;
2458         }
2459         n = rb_last(root);
2460         if (n) {
2461                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2462                 last = entry->bytenr;
2463         }
2464         n = root->rb_node;
2465
2466         while (n) {
2467                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2468                 WARN_ON(!entry->in_tree);
2469
2470                 middle = entry->bytenr;
2471
2472                 if (alt)
2473                         n = n->rb_left;
2474                 else
2475                         n = n->rb_right;
2476
2477                 alt = 1 - alt;
2478         }
2479         return middle;
2480 }
2481 #endif
2482
2483 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2484                                          struct btrfs_fs_info *fs_info)
2485 {
2486         struct qgroup_update *qgroup_update;
2487         int ret = 0;
2488
2489         if (list_empty(&trans->qgroup_ref_list) !=
2490             !trans->delayed_ref_elem.seq) {
2491                 /* list without seq or seq without list */
2492                 btrfs_err(fs_info,
2493                         "qgroup accounting update error, list is%s empty, seq is %#x.%x",
2494                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2495                         (u32)(trans->delayed_ref_elem.seq >> 32),
2496                         (u32)trans->delayed_ref_elem.seq);
2497                 BUG();
2498         }
2499
2500         if (!trans->delayed_ref_elem.seq)
2501                 return 0;
2502
2503         while (!list_empty(&trans->qgroup_ref_list)) {
2504                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2505                                                  struct qgroup_update, list);
2506                 list_del(&qgroup_update->list);
2507                 if (!ret)
2508                         ret = btrfs_qgroup_account_ref(
2509                                         trans, fs_info, qgroup_update->node,
2510                                         qgroup_update->extent_op);
2511                 kfree(qgroup_update);
2512         }
2513
2514         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2515
2516         return ret;
2517 }
2518
2519 static int refs_newer(struct btrfs_delayed_ref_root *delayed_refs, int seq,
2520                       int count)
2521 {
2522         int val = atomic_read(&delayed_refs->ref_seq);
2523
2524         if (val < seq || val >= seq + count)
2525                 return 1;
2526         return 0;
2527 }
2528
2529 /*
2530  * this starts processing the delayed reference count updates and
2531  * extent insertions we have queued up so far.  count can be
2532  * 0, which means to process everything in the tree at the start
2533  * of the run (but not newly added entries), or it can be some target
2534  * number you'd like to process.
2535  *
2536  * Returns 0 on success or if called with an aborted transaction
2537  * Returns <0 on error and aborts the transaction
2538  */
2539 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2540                            struct btrfs_root *root, unsigned long count)
2541 {
2542         struct rb_node *node;
2543         struct btrfs_delayed_ref_root *delayed_refs;
2544         struct btrfs_delayed_ref_node *ref;
2545         struct list_head cluster;
2546         int ret;
2547         u64 delayed_start;
2548         int run_all = count == (unsigned long)-1;
2549         int run_most = 0;
2550         int loops;
2551
2552         /* We'll clean this up in btrfs_cleanup_transaction */
2553         if (trans->aborted)
2554                 return 0;
2555
2556         if (root == root->fs_info->extent_root)
2557                 root = root->fs_info->tree_root;
2558
2559         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2560
2561         delayed_refs = &trans->transaction->delayed_refs;
2562         INIT_LIST_HEAD(&cluster);
2563         if (count == 0) {
2564                 count = delayed_refs->num_entries * 2;
2565                 run_most = 1;
2566         }
2567
2568         if (!run_all && !run_most) {
2569                 int old;
2570                 int seq = atomic_read(&delayed_refs->ref_seq);
2571
2572 progress:
2573                 old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2574                 if (old) {
2575                         DEFINE_WAIT(__wait);
2576                         if (delayed_refs->num_entries < 16348)
2577                                 return 0;
2578
2579                         prepare_to_wait(&delayed_refs->wait, &__wait,
2580                                         TASK_UNINTERRUPTIBLE);
2581
2582                         old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2583                         if (old) {
2584                                 schedule();
2585                                 finish_wait(&delayed_refs->wait, &__wait);
2586
2587                                 if (!refs_newer(delayed_refs, seq, 256))
2588                                         goto progress;
2589                                 else
2590                                         return 0;
2591                         } else {
2592                                 finish_wait(&delayed_refs->wait, &__wait);
2593                                 goto again;
2594                         }
2595                 }
2596
2597         } else {
2598                 atomic_inc(&delayed_refs->procs_running_refs);
2599         }
2600
2601 again:
2602         loops = 0;
2603         spin_lock(&delayed_refs->lock);
2604
2605 #ifdef SCRAMBLE_DELAYED_REFS
2606         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2607 #endif
2608
2609         while (1) {
2610                 if (!(run_all || run_most) &&
2611                     delayed_refs->num_heads_ready < 64)
2612                         break;
2613
2614                 /*
2615                  * go find something we can process in the rbtree.  We start at
2616                  * the beginning of the tree, and then build a cluster
2617                  * of refs to process starting at the first one we are able to
2618                  * lock
2619                  */
2620                 delayed_start = delayed_refs->run_delayed_start;
2621                 ret = btrfs_find_ref_cluster(trans, &cluster,
2622                                              delayed_refs->run_delayed_start);
2623                 if (ret)
2624                         break;
2625
2626                 ret = run_clustered_refs(trans, root, &cluster);
2627                 if (ret < 0) {
2628                         btrfs_release_ref_cluster(&cluster);
2629                         spin_unlock(&delayed_refs->lock);
2630                         btrfs_abort_transaction(trans, root, ret);
2631                         atomic_dec(&delayed_refs->procs_running_refs);
2632                         return ret;
2633                 }
2634
2635                 atomic_add(ret, &delayed_refs->ref_seq);
2636
2637                 count -= min_t(unsigned long, ret, count);
2638
2639                 if (count == 0)
2640                         break;
2641
2642                 if (delayed_start >= delayed_refs->run_delayed_start) {
2643                         if (loops == 0) {
2644                                 /*
2645                                  * btrfs_find_ref_cluster looped. let's do one
2646                                  * more cycle. if we don't run any delayed ref
2647                                  * during that cycle (because we can't because
2648                                  * all of them are blocked), bail out.
2649                                  */
2650                                 loops = 1;
2651                         } else {
2652                                 /*
2653                                  * no runnable refs left, stop trying
2654                                  */
2655                                 BUG_ON(run_all);
2656                                 break;
2657                         }
2658                 }
2659                 if (ret) {
2660                         /* refs were run, let's reset staleness detection */
2661                         loops = 0;
2662                 }
2663         }
2664
2665         if (run_all) {
2666                 if (!list_empty(&trans->new_bgs)) {
2667                         spin_unlock(&delayed_refs->lock);
2668                         btrfs_create_pending_block_groups(trans, root);
2669                         spin_lock(&delayed_refs->lock);
2670                 }
2671
2672                 node = rb_first(&delayed_refs->root);
2673                 if (!node)
2674                         goto out;
2675                 count = (unsigned long)-1;
2676
2677                 while (node) {
2678                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2679                                        rb_node);
2680                         if (btrfs_delayed_ref_is_head(ref)) {
2681                                 struct btrfs_delayed_ref_head *head;
2682
2683                                 head = btrfs_delayed_node_to_head(ref);
2684                                 atomic_inc(&ref->refs);
2685
2686                                 spin_unlock(&delayed_refs->lock);
2687                                 /*
2688                                  * Mutex was contended, block until it's
2689                                  * released and try again
2690                                  */
2691                                 mutex_lock(&head->mutex);
2692                                 mutex_unlock(&head->mutex);
2693
2694                                 btrfs_put_delayed_ref(ref);
2695                                 cond_resched();
2696                                 goto again;
2697                         }
2698                         node = rb_next(node);
2699                 }
2700                 spin_unlock(&delayed_refs->lock);
2701                 schedule_timeout(1);
2702                 goto again;
2703         }
2704 out:
2705         atomic_dec(&delayed_refs->procs_running_refs);
2706         smp_mb();
2707         if (waitqueue_active(&delayed_refs->wait))
2708                 wake_up(&delayed_refs->wait);
2709
2710         spin_unlock(&delayed_refs->lock);
2711         assert_qgroups_uptodate(trans);
2712         return 0;
2713 }
2714
2715 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2716                                 struct btrfs_root *root,
2717                                 u64 bytenr, u64 num_bytes, u64 flags,
2718                                 int level, int is_data)
2719 {
2720         struct btrfs_delayed_extent_op *extent_op;
2721         int ret;
2722
2723         extent_op = btrfs_alloc_delayed_extent_op();
2724         if (!extent_op)
2725                 return -ENOMEM;
2726
2727         extent_op->flags_to_set = flags;
2728         extent_op->update_flags = 1;
2729         extent_op->update_key = 0;
2730         extent_op->is_data = is_data ? 1 : 0;
2731         extent_op->level = level;
2732
2733         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2734                                           num_bytes, extent_op);
2735         if (ret)
2736                 btrfs_free_delayed_extent_op(extent_op);
2737         return ret;
2738 }
2739
2740 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2741                                       struct btrfs_root *root,
2742                                       struct btrfs_path *path,
2743                                       u64 objectid, u64 offset, u64 bytenr)
2744 {
2745         struct btrfs_delayed_ref_head *head;
2746         struct btrfs_delayed_ref_node *ref;
2747         struct btrfs_delayed_data_ref *data_ref;
2748         struct btrfs_delayed_ref_root *delayed_refs;
2749         struct rb_node *node;
2750         int ret = 0;
2751
2752         ret = -ENOENT;
2753         delayed_refs = &trans->transaction->delayed_refs;
2754         spin_lock(&delayed_refs->lock);
2755         head = btrfs_find_delayed_ref_head(trans, bytenr);
2756         if (!head)
2757                 goto out;
2758
2759         if (!mutex_trylock(&head->mutex)) {
2760                 atomic_inc(&head->node.refs);
2761                 spin_unlock(&delayed_refs->lock);
2762
2763                 btrfs_release_path(path);
2764
2765                 /*
2766                  * Mutex was contended, block until it's released and let
2767                  * caller try again
2768                  */
2769                 mutex_lock(&head->mutex);
2770                 mutex_unlock(&head->mutex);
2771                 btrfs_put_delayed_ref(&head->node);
2772                 return -EAGAIN;
2773         }
2774
2775         node = rb_prev(&head->node.rb_node);
2776         if (!node)
2777                 goto out_unlock;
2778
2779         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2780
2781         if (ref->bytenr != bytenr)
2782                 goto out_unlock;
2783
2784         ret = 1;
2785         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2786                 goto out_unlock;
2787
2788         data_ref = btrfs_delayed_node_to_data_ref(ref);
2789
2790         node = rb_prev(node);
2791         if (node) {
2792                 int seq = ref->seq;
2793
2794                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2795                 if (ref->bytenr == bytenr && ref->seq == seq)
2796                         goto out_unlock;
2797         }
2798
2799         if (data_ref->root != root->root_key.objectid ||
2800             data_ref->objectid != objectid || data_ref->offset != offset)
2801                 goto out_unlock;
2802
2803         ret = 0;
2804 out_unlock:
2805         mutex_unlock(&head->mutex);
2806 out:
2807         spin_unlock(&delayed_refs->lock);
2808         return ret;
2809 }
2810
2811 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2812                                         struct btrfs_root *root,
2813                                         struct btrfs_path *path,
2814                                         u64 objectid, u64 offset, u64 bytenr)
2815 {
2816         struct btrfs_root *extent_root = root->fs_info->extent_root;
2817         struct extent_buffer *leaf;
2818         struct btrfs_extent_data_ref *ref;
2819         struct btrfs_extent_inline_ref *iref;
2820         struct btrfs_extent_item *ei;
2821         struct btrfs_key key;
2822         u32 item_size;
2823         int ret;
2824
2825         key.objectid = bytenr;
2826         key.offset = (u64)-1;
2827         key.type = BTRFS_EXTENT_ITEM_KEY;
2828
2829         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2830         if (ret < 0)
2831                 goto out;
2832         BUG_ON(ret == 0); /* Corruption */
2833
2834         ret = -ENOENT;
2835         if (path->slots[0] == 0)
2836                 goto out;
2837
2838         path->slots[0]--;
2839         leaf = path->nodes[0];
2840         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2841
2842         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2843                 goto out;
2844
2845         ret = 1;
2846         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2847 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2848         if (item_size < sizeof(*ei)) {
2849                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2850                 goto out;
2851         }
2852 #endif
2853         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2854
2855         if (item_size != sizeof(*ei) +
2856             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2857                 goto out;
2858
2859         if (btrfs_extent_generation(leaf, ei) <=
2860             btrfs_root_last_snapshot(&root->root_item))
2861                 goto out;
2862
2863         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2864         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2865             BTRFS_EXTENT_DATA_REF_KEY)
2866                 goto out;
2867
2868         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2869         if (btrfs_extent_refs(leaf, ei) !=
2870             btrfs_extent_data_ref_count(leaf, ref) ||
2871             btrfs_extent_data_ref_root(leaf, ref) !=
2872             root->root_key.objectid ||
2873             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2874             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2875                 goto out;
2876
2877         ret = 0;
2878 out:
2879         return ret;
2880 }
2881
2882 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2883                           struct btrfs_root *root,
2884                           u64 objectid, u64 offset, u64 bytenr)
2885 {
2886         struct btrfs_path *path;
2887         int ret;
2888         int ret2;
2889
2890         path = btrfs_alloc_path();
2891         if (!path)
2892                 return -ENOENT;
2893
2894         do {
2895                 ret = check_committed_ref(trans, root, path, objectid,
2896                                           offset, bytenr);
2897                 if (ret && ret != -ENOENT)
2898                         goto out;
2899
2900                 ret2 = check_delayed_ref(trans, root, path, objectid,
2901                                          offset, bytenr);
2902         } while (ret2 == -EAGAIN);
2903
2904         if (ret2 && ret2 != -ENOENT) {
2905                 ret = ret2;
2906                 goto out;
2907         }
2908
2909         if (ret != -ENOENT || ret2 != -ENOENT)
2910                 ret = 0;
2911 out:
2912         btrfs_free_path(path);
2913         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2914                 WARN_ON(ret > 0);
2915         return ret;
2916 }
2917
2918 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2919                            struct btrfs_root *root,
2920                            struct extent_buffer *buf,
2921                            int full_backref, int inc, int for_cow)
2922 {
2923         u64 bytenr;
2924         u64 num_bytes;
2925         u64 parent;
2926         u64 ref_root;
2927         u32 nritems;
2928         struct btrfs_key key;
2929         struct btrfs_file_extent_item *fi;
2930         int i;
2931         int level;
2932         int ret = 0;
2933         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2934                             u64, u64, u64, u64, u64, u64, int);
2935
2936         ref_root = btrfs_header_owner(buf);
2937         nritems = btrfs_header_nritems(buf);
2938         level = btrfs_header_level(buf);
2939
2940         if (!root->ref_cows && level == 0)
2941                 return 0;
2942
2943         if (inc)
2944                 process_func = btrfs_inc_extent_ref;
2945         else
2946                 process_func = btrfs_free_extent;
2947
2948         if (full_backref)
2949                 parent = buf->start;
2950         else
2951                 parent = 0;
2952
2953         for (i = 0; i < nritems; i++) {
2954                 if (level == 0) {
2955                         btrfs_item_key_to_cpu(buf, &key, i);
2956                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2957                                 continue;
2958                         fi = btrfs_item_ptr(buf, i,
2959                                             struct btrfs_file_extent_item);
2960                         if (btrfs_file_extent_type(buf, fi) ==
2961                             BTRFS_FILE_EXTENT_INLINE)
2962                                 continue;
2963                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2964                         if (bytenr == 0)
2965                                 continue;
2966
2967                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2968                         key.offset -= btrfs_file_extent_offset(buf, fi);
2969                         ret = process_func(trans, root, bytenr, num_bytes,
2970                                            parent, ref_root, key.objectid,
2971                                            key.offset, for_cow);
2972                         if (ret)
2973                                 goto fail;
2974                 } else {
2975                         bytenr = btrfs_node_blockptr(buf, i);
2976                         num_bytes = btrfs_level_size(root, level - 1);
2977                         ret = process_func(trans, root, bytenr, num_bytes,
2978                                            parent, ref_root, level - 1, 0,
2979                                            for_cow);
2980                         if (ret)
2981                                 goto fail;
2982                 }
2983         }
2984         return 0;
2985 fail:
2986         return ret;
2987 }
2988
2989 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2990                   struct extent_buffer *buf, int full_backref, int for_cow)
2991 {
2992         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
2993 }
2994
2995 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2996                   struct extent_buffer *buf, int full_backref, int for_cow)
2997 {
2998         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
2999 }
3000
3001 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3002                                  struct btrfs_root *root,
3003                                  struct btrfs_path *path,
3004                                  struct btrfs_block_group_cache *cache)
3005 {
3006         int ret;
3007         struct btrfs_root *extent_root = root->fs_info->extent_root;
3008         unsigned long bi;
3009         struct extent_buffer *leaf;
3010
3011         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3012         if (ret < 0)
3013                 goto fail;
3014         BUG_ON(ret); /* Corruption */
3015
3016         leaf = path->nodes[0];
3017         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3018         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3019         btrfs_mark_buffer_dirty(leaf);
3020         btrfs_release_path(path);
3021 fail:
3022         if (ret) {
3023                 btrfs_abort_transaction(trans, root, ret);
3024                 return ret;
3025         }
3026         return 0;
3027
3028 }
3029
3030 static struct btrfs_block_group_cache *
3031 next_block_group(struct btrfs_root *root,
3032                  struct btrfs_block_group_cache *cache)
3033 {
3034         struct rb_node *node;
3035         spin_lock(&root->fs_info->block_group_cache_lock);
3036         node = rb_next(&cache->cache_node);
3037         btrfs_put_block_group(cache);
3038         if (node) {
3039                 cache = rb_entry(node, struct btrfs_block_group_cache,
3040                                  cache_node);
3041                 btrfs_get_block_group(cache);
3042         } else
3043                 cache = NULL;
3044         spin_unlock(&root->fs_info->block_group_cache_lock);
3045         return cache;
3046 }
3047
3048 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3049                             struct btrfs_trans_handle *trans,
3050                             struct btrfs_path *path)
3051 {
3052         struct btrfs_root *root = block_group->fs_info->tree_root;
3053         struct inode *inode = NULL;
3054         u64 alloc_hint = 0;
3055         int dcs = BTRFS_DC_ERROR;
3056         int num_pages = 0;
3057         int retries = 0;
3058         int ret = 0;
3059
3060         /*
3061          * If this block group is smaller than 100 megs don't bother caching the
3062          * block group.
3063          */
3064         if (block_group->key.offset < (100 * 1024 * 1024)) {
3065                 spin_lock(&block_group->lock);
3066                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3067                 spin_unlock(&block_group->lock);
3068                 return 0;
3069         }
3070
3071 again:
3072         inode = lookup_free_space_inode(root, block_group, path);
3073         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3074                 ret = PTR_ERR(inode);
3075                 btrfs_release_path(path);
3076                 goto out;
3077         }
3078
3079         if (IS_ERR(inode)) {
3080                 BUG_ON(retries);
3081                 retries++;
3082
3083                 if (block_group->ro)
3084                         goto out_free;
3085
3086                 ret = create_free_space_inode(root, trans, block_group, path);
3087                 if (ret)
3088                         goto out_free;
3089                 goto again;
3090         }
3091
3092         /* We've already setup this transaction, go ahead and exit */
3093         if (block_group->cache_generation == trans->transid &&
3094             i_size_read(inode)) {
3095                 dcs = BTRFS_DC_SETUP;
3096                 goto out_put;
3097         }
3098
3099         /*
3100          * We want to set the generation to 0, that way if anything goes wrong
3101          * from here on out we know not to trust this cache when we load up next
3102          * time.
3103          */
3104         BTRFS_I(inode)->generation = 0;
3105         ret = btrfs_update_inode(trans, root, inode);
3106         WARN_ON(ret);
3107
3108         if (i_size_read(inode) > 0) {
3109                 ret = btrfs_check_trunc_cache_free_space(root,
3110                                         &root->fs_info->global_block_rsv);
3111                 if (ret)
3112                         goto out_put;
3113
3114                 ret = btrfs_truncate_free_space_cache(root, trans, path,
3115                                                       inode);
3116                 if (ret)
3117                         goto out_put;
3118         }
3119
3120         spin_lock(&block_group->lock);
3121         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3122             !btrfs_test_opt(root, SPACE_CACHE)) {
3123                 /*
3124                  * don't bother trying to write stuff out _if_
3125                  * a) we're not cached,
3126                  * b) we're with nospace_cache mount option.
3127                  */
3128                 dcs = BTRFS_DC_WRITTEN;
3129                 spin_unlock(&block_group->lock);
3130                 goto out_put;
3131         }
3132         spin_unlock(&block_group->lock);
3133
3134         /*
3135          * Try to preallocate enough space based on how big the block group is.
3136          * Keep in mind this has to include any pinned space which could end up
3137          * taking up quite a bit since it's not folded into the other space
3138          * cache.
3139          */
3140         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3141         if (!num_pages)
3142                 num_pages = 1;
3143
3144         num_pages *= 16;
3145         num_pages *= PAGE_CACHE_SIZE;
3146
3147         ret = btrfs_check_data_free_space(inode, num_pages);
3148         if (ret)
3149                 goto out_put;
3150
3151         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3152                                               num_pages, num_pages,
3153                                               &alloc_hint);
3154         if (!ret)
3155                 dcs = BTRFS_DC_SETUP;
3156         btrfs_free_reserved_data_space(inode, num_pages);
3157
3158 out_put:
3159         iput(inode);
3160 out_free:
3161         btrfs_release_path(path);
3162 out:
3163         spin_lock(&block_group->lock);
3164         if (!ret && dcs == BTRFS_DC_SETUP)
3165                 block_group->cache_generation = trans->transid;
3166         block_group->disk_cache_state = dcs;
3167         spin_unlock(&block_group->lock);
3168
3169         return ret;
3170 }
3171
3172 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3173                                    struct btrfs_root *root)
3174 {
3175         struct btrfs_block_group_cache *cache;
3176         int err = 0;
3177         struct btrfs_path *path;
3178         u64 last = 0;
3179
3180         path = btrfs_alloc_path();
3181         if (!path)
3182                 return -ENOMEM;
3183
3184 again:
3185         while (1) {
3186                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3187                 while (cache) {
3188                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3189                                 break;
3190                         cache = next_block_group(root, cache);
3191                 }
3192                 if (!cache) {
3193                         if (last == 0)
3194                                 break;
3195                         last = 0;
3196                         continue;
3197                 }
3198                 err = cache_save_setup(cache, trans, path);
3199                 last = cache->key.objectid + cache->key.offset;
3200                 btrfs_put_block_group(cache);
3201         }
3202
3203         while (1) {
3204                 if (last == 0) {
3205                         err = btrfs_run_delayed_refs(trans, root,
3206                                                      (unsigned long)-1);
3207                         if (err) /* File system offline */
3208                                 goto out;
3209                 }
3210
3211                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3212                 while (cache) {
3213                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3214                                 btrfs_put_block_group(cache);
3215                                 goto again;
3216                         }
3217
3218                         if (cache->dirty)
3219                                 break;
3220                         cache = next_block_group(root, cache);
3221                 }
3222                 if (!cache) {
3223                         if (last == 0)
3224                                 break;
3225                         last = 0;
3226                         continue;
3227                 }
3228
3229                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3230                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3231                 cache->dirty = 0;
3232                 last = cache->key.objectid + cache->key.offset;
3233
3234                 err = write_one_cache_group(trans, root, path, cache);
3235                 if (err) /* File system offline */
3236                         goto out;
3237
3238                 btrfs_put_block_group(cache);
3239         }
3240
3241         while (1) {
3242                 /*
3243                  * I don't think this is needed since we're just marking our
3244                  * preallocated extent as written, but just in case it can't
3245                  * hurt.
3246                  */
3247                 if (last == 0) {
3248                         err = btrfs_run_delayed_refs(trans, root,
3249                                                      (unsigned long)-1);
3250                         if (err) /* File system offline */
3251                                 goto out;
3252                 }
3253
3254                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3255                 while (cache) {
3256                         /*
3257                          * Really this shouldn't happen, but it could if we
3258                          * couldn't write the entire preallocated extent and
3259                          * splitting the extent resulted in a new block.
3260                          */
3261                         if (cache->dirty) {
3262                                 btrfs_put_block_group(cache);
3263                                 goto again;
3264                         }
3265                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3266                                 break;
3267                         cache = next_block_group(root, cache);
3268                 }
3269                 if (!cache) {
3270                         if (last == 0)
3271                                 break;
3272                         last = 0;
3273                         continue;
3274                 }
3275
3276                 err = btrfs_write_out_cache(root, trans, cache, path);
3277
3278                 /*
3279                  * If we didn't have an error then the cache state is still
3280                  * NEED_WRITE, so we can set it to WRITTEN.
3281                  */
3282                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3283                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3284                 last = cache->key.objectid + cache->key.offset;
3285                 btrfs_put_block_group(cache);
3286         }
3287 out:
3288
3289         btrfs_free_path(path);
3290         return err;
3291 }
3292
3293 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3294 {
3295         struct btrfs_block_group_cache *block_group;
3296         int readonly = 0;
3297
3298         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3299         if (!block_group || block_group->ro)
3300                 readonly = 1;
3301         if (block_group)
3302                 btrfs_put_block_group(block_group);
3303         return readonly;
3304 }
3305
3306 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3307                              u64 total_bytes, u64 bytes_used,
3308                              struct btrfs_space_info **space_info)
3309 {
3310         struct btrfs_space_info *found;
3311         int i;
3312         int factor;
3313
3314         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3315                      BTRFS_BLOCK_GROUP_RAID10))
3316                 factor = 2;
3317         else
3318                 factor = 1;
3319
3320         found = __find_space_info(info, flags);
3321         if (found) {
3322                 spin_lock(&found->lock);
3323                 found->total_bytes += total_bytes;
3324                 found->disk_total += total_bytes * factor;
3325                 found->bytes_used += bytes_used;
3326                 found->disk_used += bytes_used * factor;
3327                 found->full = 0;
3328                 spin_unlock(&found->lock);
3329                 *space_info = found;
3330                 return 0;
3331         }
3332         found = kzalloc(sizeof(*found), GFP_NOFS);
3333         if (!found)
3334                 return -ENOMEM;
3335
3336         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3337                 INIT_LIST_HEAD(&found->block_groups[i]);
3338         init_rwsem(&found->groups_sem);
3339         spin_lock_init(&found->lock);
3340         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3341         found->total_bytes = total_bytes;
3342         found->disk_total = total_bytes * factor;
3343         found->bytes_used = bytes_used;
3344         found->disk_used = bytes_used * factor;
3345         found->bytes_pinned = 0;
3346         found->bytes_reserved = 0;
3347         found->bytes_readonly = 0;
3348         found->bytes_may_use = 0;
3349         found->full = 0;
3350         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3351         found->chunk_alloc = 0;
3352         found->flush = 0;
3353         init_waitqueue_head(&found->wait);
3354         *space_info = found;
3355         list_add_rcu(&found->list, &info->space_info);
3356         if (flags & BTRFS_BLOCK_GROUP_DATA)
3357                 info->data_sinfo = found;
3358         return 0;
3359 }
3360
3361 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3362 {
3363         u64 extra_flags = chunk_to_extended(flags) &
3364                                 BTRFS_EXTENDED_PROFILE_MASK;
3365
3366         write_seqlock(&fs_info->profiles_lock);
3367         if (flags & BTRFS_BLOCK_GROUP_DATA)
3368                 fs_info->avail_data_alloc_bits |= extra_flags;
3369         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3370                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3371         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3372                 fs_info->avail_system_alloc_bits |= extra_flags;
3373         write_sequnlock(&fs_info->profiles_lock);
3374 }
3375
3376 /*
3377  * returns target flags in extended format or 0 if restripe for this
3378  * chunk_type is not in progress
3379  *
3380  * should be called with either volume_mutex or balance_lock held
3381  */
3382 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3383 {
3384         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3385         u64 target = 0;
3386
3387         if (!bctl)
3388                 return 0;
3389
3390         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3391             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3392                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3393         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3394                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3395                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3396         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3397                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3398                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3399         }
3400
3401         return target;
3402 }
3403
3404 /*
3405  * @flags: available profiles in extended format (see ctree.h)
3406  *
3407  * Returns reduced profile in chunk format.  If profile changing is in
3408  * progress (either running or paused) picks the target profile (if it's
3409  * already available), otherwise falls back to plain reducing.
3410  */
3411 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3412 {
3413         /*
3414          * we add in the count of missing devices because we want
3415          * to make sure that any RAID levels on a degraded FS
3416          * continue to be honored.
3417          */
3418         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3419                 root->fs_info->fs_devices->missing_devices;
3420         u64 target;
3421         u64 tmp;
3422
3423         /*
3424          * see if restripe for this chunk_type is in progress, if so
3425          * try to reduce to the target profile
3426          */
3427         spin_lock(&root->fs_info->balance_lock);
3428         target = get_restripe_target(root->fs_info, flags);
3429         if (target) {
3430                 /* pick target profile only if it's already available */
3431                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3432                         spin_unlock(&root->fs_info->balance_lock);
3433                         return extended_to_chunk(target);
3434                 }
3435         }
3436         spin_unlock(&root->fs_info->balance_lock);
3437
3438         /* First, mask out the RAID levels which aren't possible */
3439         if (num_devices == 1)
3440                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3441                            BTRFS_BLOCK_GROUP_RAID5);
3442         if (num_devices < 3)
3443                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3444         if (num_devices < 4)
3445                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3446
3447         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3448                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3449                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3450         flags &= ~tmp;
3451
3452         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3453                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3454         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3455                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3456         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3457                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3458         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3459                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3460         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3461                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3462
3463         return extended_to_chunk(flags | tmp);
3464 }
3465
3466 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3467 {
3468         unsigned seq;
3469
3470         do {
3471                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3472
3473                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3474                         flags |= root->fs_info->avail_data_alloc_bits;
3475                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3476                         flags |= root->fs_info->avail_system_alloc_bits;
3477                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3478                         flags |= root->fs_info->avail_metadata_alloc_bits;
3479         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3480
3481         return btrfs_reduce_alloc_profile(root, flags);
3482 }
3483
3484 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3485 {
3486         u64 flags;
3487         u64 ret;
3488
3489         if (data)
3490                 flags = BTRFS_BLOCK_GROUP_DATA;
3491         else if (root == root->fs_info->chunk_root)
3492                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3493         else
3494                 flags = BTRFS_BLOCK_GROUP_METADATA;
3495
3496         ret = get_alloc_profile(root, flags);
3497         return ret;
3498 }
3499
3500 /*
3501  * This will check the space that the inode allocates from to make sure we have
3502  * enough space for bytes.
3503  */
3504 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3505 {
3506         struct btrfs_space_info *data_sinfo;
3507         struct btrfs_root *root = BTRFS_I(inode)->root;
3508         struct btrfs_fs_info *fs_info = root->fs_info;
3509         u64 used;
3510         int ret = 0, committed = 0, alloc_chunk = 1;
3511
3512         /* make sure bytes are sectorsize aligned */
3513         bytes = ALIGN(bytes, root->sectorsize);
3514
3515         if (root == root->fs_info->tree_root ||
3516             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3517                 alloc_chunk = 0;
3518                 committed = 1;
3519         }
3520
3521         data_sinfo = fs_info->data_sinfo;
3522         if (!data_sinfo)
3523                 goto alloc;
3524
3525 again:
3526         /* make sure we have enough space to handle the data first */
3527         spin_lock(&data_sinfo->lock);
3528         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3529                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3530                 data_sinfo->bytes_may_use;
3531
3532         if (used + bytes > data_sinfo->total_bytes) {
3533                 struct btrfs_trans_handle *trans;
3534
3535                 /*
3536                  * if we don't have enough free bytes in this space then we need
3537                  * to alloc a new chunk.
3538                  */
3539                 if (!data_sinfo->full && alloc_chunk) {
3540                         u64 alloc_target;
3541
3542                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3543                         spin_unlock(&data_sinfo->lock);
3544 alloc:
3545                         alloc_target = btrfs_get_alloc_profile(root, 1);
3546                         trans = btrfs_join_transaction(root);
3547                         if (IS_ERR(trans))
3548                                 return PTR_ERR(trans);
3549
3550                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3551                                              alloc_target,
3552                                              CHUNK_ALLOC_NO_FORCE);
3553                         btrfs_end_transaction(trans, root);
3554                         if (ret < 0) {
3555                                 if (ret != -ENOSPC)
3556                                         return ret;
3557                                 else
3558                                         goto commit_trans;
3559                         }
3560
3561                         if (!data_sinfo)
3562                                 data_sinfo = fs_info->data_sinfo;
3563
3564                         goto again;
3565                 }
3566
3567                 /*
3568                  * If we have less pinned bytes than we want to allocate then
3569                  * don't bother committing the transaction, it won't help us.
3570                  */
3571                 if (data_sinfo->bytes_pinned < bytes)
3572                         committed = 1;
3573                 spin_unlock(&data_sinfo->lock);
3574
3575                 /* commit the current transaction and try again */
3576 commit_trans:
3577                 if (!committed &&
3578                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3579                         committed = 1;
3580                         trans = btrfs_join_transaction(root);
3581                         if (IS_ERR(trans))
3582                                 return PTR_ERR(trans);
3583                         ret = btrfs_commit_transaction(trans, root);
3584                         if (ret)
3585                                 return ret;
3586                         goto again;
3587                 }
3588
3589                 return -ENOSPC;
3590         }
3591         data_sinfo->bytes_may_use += bytes;
3592         trace_btrfs_space_reservation(root->fs_info, "space_info",
3593                                       data_sinfo->flags, bytes, 1);
3594         spin_unlock(&data_sinfo->lock);
3595
3596         return 0;
3597 }
3598
3599 /*
3600  * Called if we need to clear a data reservation for this inode.
3601  */
3602 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3603 {
3604         struct btrfs_root *root = BTRFS_I(inode)->root;
3605         struct btrfs_space_info *data_sinfo;
3606
3607         /* make sure bytes are sectorsize aligned */
3608         bytes = ALIGN(bytes, root->sectorsize);
3609
3610         data_sinfo = root->fs_info->data_sinfo;
3611         spin_lock(&data_sinfo->lock);
3612         data_sinfo->bytes_may_use -= bytes;
3613         trace_btrfs_space_reservation(root->fs_info, "space_info",
3614                                       data_sinfo->flags, bytes, 0);
3615         spin_unlock(&data_sinfo->lock);
3616 }
3617
3618 static void force_metadata_allocation(struct btrfs_fs_info *info)
3619 {
3620         struct list_head *head = &info->space_info;
3621         struct btrfs_space_info *found;
3622
3623         rcu_read_lock();
3624         list_for_each_entry_rcu(found, head, list) {
3625                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3626                         found->force_alloc = CHUNK_ALLOC_FORCE;
3627         }
3628         rcu_read_unlock();
3629 }
3630
3631 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3632 {
3633         return (global->size << 1);
3634 }
3635
3636 static int should_alloc_chunk(struct btrfs_root *root,
3637                               struct btrfs_space_info *sinfo, int force)
3638 {
3639         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3640         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3641         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3642         u64 thresh;
3643
3644         if (force == CHUNK_ALLOC_FORCE)
3645                 return 1;
3646
3647         /*
3648          * We need to take into account the global rsv because for all intents
3649          * and purposes it's used space.  Don't worry about locking the
3650          * global_rsv, it doesn't change except when the transaction commits.
3651          */
3652         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3653                 num_allocated += calc_global_rsv_need_space(global_rsv);
3654
3655         /*
3656          * in limited mode, we want to have some free space up to
3657          * about 1% of the FS size.
3658          */
3659         if (force == CHUNK_ALLOC_LIMITED) {
3660                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3661                 thresh = max_t(u64, 64 * 1024 * 1024,
3662                                div_factor_fine(thresh, 1));
3663
3664                 if (num_bytes - num_allocated < thresh)
3665                         return 1;
3666         }
3667
3668         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3669                 return 0;
3670         return 1;
3671 }
3672
3673 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3674 {
3675         u64 num_dev;
3676
3677         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3678                     BTRFS_BLOCK_GROUP_RAID0 |
3679                     BTRFS_BLOCK_GROUP_RAID5 |
3680                     BTRFS_BLOCK_GROUP_RAID6))
3681                 num_dev = root->fs_info->fs_devices->rw_devices;
3682         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3683                 num_dev = 2;
3684         else
3685                 num_dev = 1;    /* DUP or single */
3686
3687         /* metadata for updaing devices and chunk tree */
3688         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3689 }
3690
3691 static void check_system_chunk(struct btrfs_trans_handle *trans,
3692                                struct btrfs_root *root, u64 type)
3693 {
3694         struct btrfs_space_info *info;
3695         u64 left;
3696         u64 thresh;
3697
3698         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3699         spin_lock(&info->lock);
3700         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3701                 info->bytes_reserved - info->bytes_readonly;
3702         spin_unlock(&info->lock);
3703
3704         thresh = get_system_chunk_thresh(root, type);
3705         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3706                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3707                         left, thresh, type);
3708                 dump_space_info(info, 0, 0);
3709         }
3710
3711         if (left < thresh) {
3712                 u64 flags;
3713
3714                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3715                 btrfs_alloc_chunk(trans, root, flags);
3716         }
3717 }
3718
3719 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3720                           struct btrfs_root *extent_root, u64 flags, int force)
3721 {
3722         struct btrfs_space_info *space_info;
3723         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3724         int wait_for_alloc = 0;
3725         int ret = 0;
3726
3727         /* Don't re-enter if we're already allocating a chunk */
3728         if (trans->allocating_chunk)
3729                 return -ENOSPC;
3730
3731         space_info = __find_space_info(extent_root->fs_info, flags);
3732         if (!space_info) {
3733                 ret = update_space_info(extent_root->fs_info, flags,
3734                                         0, 0, &space_info);
3735                 BUG_ON(ret); /* -ENOMEM */
3736         }
3737         BUG_ON(!space_info); /* Logic error */
3738
3739 again:
3740         spin_lock(&space_info->lock);
3741         if (force < space_info->force_alloc)
3742                 force = space_info->force_alloc;
3743         if (space_info->full) {
3744                 spin_unlock(&space_info->lock);
3745                 return 0;
3746         }
3747
3748         if (!should_alloc_chunk(extent_root, space_info, force)) {
3749                 spin_unlock(&space_info->lock);
3750                 return 0;
3751         } else if (space_info->chunk_alloc) {
3752                 wait_for_alloc = 1;
3753         } else {
3754                 space_info->chunk_alloc = 1;
3755         }
3756
3757         spin_unlock(&space_info->lock);
3758
3759         mutex_lock(&fs_info->chunk_mutex);
3760
3761         /*
3762          * The chunk_mutex is held throughout the entirety of a chunk
3763          * allocation, so once we've acquired the chunk_mutex we know that the
3764          * other guy is done and we need to recheck and see if we should
3765          * allocate.
3766          */
3767         if (wait_for_alloc) {
3768                 mutex_unlock(&fs_info->chunk_mutex);
3769                 wait_for_alloc = 0;
3770                 goto again;
3771         }
3772
3773         trans->allocating_chunk = true;
3774
3775         /*
3776          * If we have mixed data/metadata chunks we want to make sure we keep
3777          * allocating mixed chunks instead of individual chunks.
3778          */
3779         if (btrfs_mixed_space_info(space_info))
3780                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3781
3782         /*
3783          * if we're doing a data chunk, go ahead and make sure that
3784          * we keep a reasonable number of metadata chunks allocated in the
3785          * FS as well.
3786          */
3787         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3788                 fs_info->data_chunk_allocations++;
3789                 if (!(fs_info->data_chunk_allocations %
3790                       fs_info->metadata_ratio))
3791                         force_metadata_allocation(fs_info);
3792         }
3793
3794         /*
3795          * Check if we have enough space in SYSTEM chunk because we may need
3796          * to update devices.
3797          */
3798         check_system_chunk(trans, extent_root, flags);
3799
3800         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3801         trans->allocating_chunk = false;
3802
3803         spin_lock(&space_info->lock);
3804         if (ret < 0 && ret != -ENOSPC)
3805                 goto out;
3806         if (ret)
3807                 space_info->full = 1;
3808         else
3809                 ret = 1;
3810
3811         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3812 out:
3813         space_info->chunk_alloc = 0;
3814         spin_unlock(&space_info->lock);
3815         mutex_unlock(&fs_info->chunk_mutex);
3816         return ret;
3817 }
3818
3819 static int can_overcommit(struct btrfs_root *root,
3820                           struct btrfs_space_info *space_info, u64 bytes,
3821                           enum btrfs_reserve_flush_enum flush)
3822 {
3823         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3824         u64 profile = btrfs_get_alloc_profile(root, 0);
3825         u64 space_size;
3826         u64 avail;
3827         u64 used;
3828         u64 to_add;
3829
3830         used = space_info->bytes_used + space_info->bytes_reserved +
3831                 space_info->bytes_pinned + space_info->bytes_readonly;
3832
3833         /*
3834          * We only want to allow over committing if we have lots of actual space
3835          * free, but if we don't have enough space to handle the global reserve
3836          * space then we could end up having a real enospc problem when trying
3837          * to allocate a chunk or some other such important allocation.
3838          */
3839         spin_lock(&global_rsv->lock);
3840         space_size = calc_global_rsv_need_space(global_rsv);
3841         spin_unlock(&global_rsv->lock);
3842         if (used + space_size >= space_info->total_bytes)
3843                 return 0;
3844
3845         used += space_info->bytes_may_use;
3846
3847         spin_lock(&root->fs_info->free_chunk_lock);
3848         avail = root->fs_info->free_chunk_space;
3849         spin_unlock(&root->fs_info->free_chunk_lock);
3850
3851         /*
3852          * If we have dup, raid1 or raid10 then only half of the free
3853          * space is actually useable.  For raid56, the space info used
3854          * doesn't include the parity drive, so we don't have to
3855          * change the math
3856          */
3857         if (profile & (BTRFS_BLOCK_GROUP_DUP |
3858                        BTRFS_BLOCK_GROUP_RAID1 |
3859                        BTRFS_BLOCK_GROUP_RAID10))
3860                 avail >>= 1;
3861
3862         to_add = space_info->total_bytes;
3863
3864         /*
3865          * If we aren't flushing all things, let us overcommit up to
3866          * 1/2th of the space. If we can flush, don't let us overcommit
3867          * too much, let it overcommit up to 1/8 of the space.
3868          */
3869         if (flush == BTRFS_RESERVE_FLUSH_ALL)
3870                 to_add >>= 3;
3871         else
3872                 to_add >>= 1;
3873
3874         /*
3875          * Limit the overcommit to the amount of free space we could possibly
3876          * allocate for chunks.
3877          */
3878         to_add = min(avail, to_add);
3879
3880         if (used + bytes < space_info->total_bytes + to_add)
3881                 return 1;
3882         return 0;
3883 }
3884
3885 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
3886                                          unsigned long nr_pages)
3887 {
3888         struct super_block *sb = root->fs_info->sb;
3889         int started;
3890
3891         /* If we can not start writeback, just sync all the delalloc file. */
3892         started = try_to_writeback_inodes_sb_nr(sb, nr_pages,
3893                                                       WB_REASON_FS_FREE_SPACE);
3894         if (!started) {
3895                 /*
3896                  * We needn't worry the filesystem going from r/w to r/o though
3897                  * we don't acquire ->s_umount mutex, because the filesystem
3898                  * should guarantee the delalloc inodes list be empty after
3899                  * the filesystem is readonly(all dirty pages are written to
3900                  * the disk).
3901                  */
3902                 btrfs_start_delalloc_inodes(root, 0);
3903                 if (!current->journal_info)
3904                         btrfs_wait_ordered_extents(root, 0);
3905         }
3906 }
3907
3908 /*
3909  * shrink metadata reservation for delalloc
3910  */
3911 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
3912                             bool wait_ordered)
3913 {
3914         struct btrfs_block_rsv *block_rsv;
3915         struct btrfs_space_info *space_info;
3916         struct btrfs_trans_handle *trans;
3917         u64 delalloc_bytes;
3918         u64 max_reclaim;
3919         long time_left;
3920         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3921         int loops = 0;
3922         enum btrfs_reserve_flush_enum flush;
3923
3924         trans = (struct btrfs_trans_handle *)current->journal_info;
3925         block_rsv = &root->fs_info->delalloc_block_rsv;
3926         space_info = block_rsv->space_info;
3927
3928         smp_mb();
3929         delalloc_bytes = percpu_counter_sum_positive(
3930                                                 &root->fs_info->delalloc_bytes);
3931         if (delalloc_bytes == 0) {
3932                 if (trans)
3933                         return;
3934                 btrfs_wait_ordered_extents(root, 0);
3935                 return;
3936         }
3937
3938         while (delalloc_bytes && loops < 3) {
3939                 max_reclaim = min(delalloc_bytes, to_reclaim);
3940                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
3941                 btrfs_writeback_inodes_sb_nr(root, nr_pages);
3942                 /*
3943                  * We need to wait for the async pages to actually start before
3944                  * we do anything.
3945                  */
3946                 wait_event(root->fs_info->async_submit_wait,
3947                            !atomic_read(&root->fs_info->async_delalloc_pages));
3948
3949                 if (!trans)
3950                         flush = BTRFS_RESERVE_FLUSH_ALL;
3951                 else
3952                         flush = BTRFS_RESERVE_NO_FLUSH;
3953                 spin_lock(&space_info->lock);
3954                 if (can_overcommit(root, space_info, orig, flush)) {
3955                         spin_unlock(&space_info->lock);
3956                         break;
3957                 }
3958                 spin_unlock(&space_info->lock);
3959
3960                 loops++;
3961                 if (wait_ordered && !trans) {
3962                         btrfs_wait_ordered_extents(root, 0);
3963                 } else {
3964                         time_left = schedule_timeout_killable(1);
3965                         if (time_left)
3966                                 break;
3967                 }
3968                 smp_mb();
3969                 delalloc_bytes = percpu_counter_sum_positive(
3970                                                 &root->fs_info->delalloc_bytes);
3971         }
3972 }
3973
3974 /**
3975  * maybe_commit_transaction - possibly commit the transaction if its ok to
3976  * @root - the root we're allocating for
3977  * @bytes - the number of bytes we want to reserve
3978  * @force - force the commit
3979  *
3980  * This will check to make sure that committing the transaction will actually
3981  * get us somewhere and then commit the transaction if it does.  Otherwise it
3982  * will return -ENOSPC.
3983  */
3984 static int may_commit_transaction(struct btrfs_root *root,
3985                                   struct btrfs_space_info *space_info,
3986                                   u64 bytes, int force)
3987 {
3988         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3989         struct btrfs_trans_handle *trans;
3990
3991         trans = (struct btrfs_trans_handle *)current->journal_info;
3992         if (trans)
3993                 return -EAGAIN;
3994
3995         if (force)
3996                 goto commit;
3997
3998         /* See if there is enough pinned space to make this reservation */
3999         spin_lock(&space_info->lock);
4000         if (space_info->bytes_pinned >= bytes) {
4001                 spin_unlock(&space_info->lock);
4002                 goto commit;
4003         }
4004         spin_unlock(&space_info->lock);
4005
4006         /*
4007          * See if there is some space in the delayed insertion reservation for
4008          * this reservation.
4009          */
4010         if (space_info != delayed_rsv->space_info)
4011                 return -ENOSPC;
4012
4013         spin_lock(&space_info->lock);
4014         spin_lock(&delayed_rsv->lock);
4015         if (space_info->bytes_pinned + delayed_rsv->size < bytes) {
4016                 spin_unlock(&delayed_rsv->lock);
4017                 spin_unlock(&space_info->lock);
4018                 return -ENOSPC;
4019         }
4020         spin_unlock(&delayed_rsv->lock);
4021         spin_unlock(&space_info->lock);
4022
4023 commit:
4024         trans = btrfs_join_transaction(root);
4025         if (IS_ERR(trans))
4026                 return -ENOSPC;
4027
4028         return btrfs_commit_transaction(trans, root);
4029 }
4030
4031 enum flush_state {
4032         FLUSH_DELAYED_ITEMS_NR  =       1,
4033         FLUSH_DELAYED_ITEMS     =       2,
4034         FLUSH_DELALLOC          =       3,
4035         FLUSH_DELALLOC_WAIT     =       4,
4036         ALLOC_CHUNK             =       5,
4037         COMMIT_TRANS            =       6,
4038 };
4039
4040 static int flush_space(struct btrfs_root *root,
4041                        struct btrfs_space_info *space_info, u64 num_bytes,
4042                        u64 orig_bytes, int state)
4043 {
4044         struct btrfs_trans_handle *trans;
4045         int nr;
4046         int ret = 0;
4047
4048         switch (state) {
4049         case FLUSH_DELAYED_ITEMS_NR:
4050         case FLUSH_DELAYED_ITEMS:
4051                 if (state == FLUSH_DELAYED_ITEMS_NR) {
4052                         u64 bytes = btrfs_calc_trans_metadata_size(root, 1);
4053
4054                         nr = (int)div64_u64(num_bytes, bytes);
4055                         if (!nr)
4056                                 nr = 1;
4057                         nr *= 2;
4058                 } else {
4059                         nr = -1;
4060                 }
4061                 trans = btrfs_join_transaction(root);
4062                 if (IS_ERR(trans)) {
4063                         ret = PTR_ERR(trans);
4064                         break;
4065                 }
4066                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4067                 btrfs_end_transaction(trans, root);
4068                 break;
4069         case FLUSH_DELALLOC:
4070         case FLUSH_DELALLOC_WAIT:
4071                 shrink_delalloc(root, num_bytes, orig_bytes,
4072                                 state == FLUSH_DELALLOC_WAIT);
4073                 break;
4074         case ALLOC_CHUNK:
4075                 trans = btrfs_join_transaction(root);
4076                 if (IS_ERR(trans)) {
4077                         ret = PTR_ERR(trans);
4078                         break;
4079                 }
4080                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4081                                      btrfs_get_alloc_profile(root, 0),
4082                                      CHUNK_ALLOC_NO_FORCE);
4083                 btrfs_end_transaction(trans, root);
4084                 if (ret == -ENOSPC)
4085                         ret = 0;
4086                 break;
4087         case COMMIT_TRANS:
4088                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4089                 break;
4090         default:
4091                 ret = -ENOSPC;
4092                 break;
4093         }
4094
4095         return ret;
4096 }
4097 /**
4098  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4099  * @root - the root we're allocating for
4100  * @block_rsv - the block_rsv we're allocating for
4101  * @orig_bytes - the number of bytes we want
4102  * @flush - whether or not we can flush to make our reservation
4103  *
4104  * This will reserve orgi_bytes number of bytes from the space info associated
4105  * with the block_rsv.  If there is not enough space it will make an attempt to
4106  * flush out space to make room.  It will do this by flushing delalloc if
4107  * possible or committing the transaction.  If flush is 0 then no attempts to
4108  * regain reservations will be made and this will fail if there is not enough
4109  * space already.
4110  */
4111 static int reserve_metadata_bytes(struct btrfs_root *root,
4112                                   struct btrfs_block_rsv *block_rsv,
4113                                   u64 orig_bytes,
4114                                   enum btrfs_reserve_flush_enum flush)
4115 {
4116         struct btrfs_space_info *space_info = block_rsv->space_info;
4117         u64 used;
4118         u64 num_bytes = orig_bytes;
4119         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4120         int ret = 0;
4121         bool flushing = false;
4122
4123 again:
4124         ret = 0;
4125         spin_lock(&space_info->lock);
4126         /*
4127          * We only want to wait if somebody other than us is flushing and we
4128          * are actually allowed to flush all things.
4129          */
4130         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4131                space_info->flush) {
4132                 spin_unlock(&space_info->lock);
4133                 /*
4134                  * If we have a trans handle we can't wait because the flusher
4135                  * may have to commit the transaction, which would mean we would
4136                  * deadlock since we are waiting for the flusher to finish, but
4137                  * hold the current transaction open.
4138                  */
4139                 if (current->journal_info)
4140                         return -EAGAIN;
4141                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4142                 /* Must have been killed, return */
4143                 if (ret)
4144                         return -EINTR;
4145
4146                 spin_lock(&space_info->lock);
4147         }
4148
4149         ret = -ENOSPC;
4150         used = space_info->bytes_used + space_info->bytes_reserved +
4151                 space_info->bytes_pinned + space_info->bytes_readonly +
4152                 space_info->bytes_may_use;
4153
4154         /*
4155          * The idea here is that we've not already over-reserved the block group
4156          * then we can go ahead and save our reservation first and then start
4157          * flushing if we need to.  Otherwise if we've already overcommitted
4158          * lets start flushing stuff first and then come back and try to make
4159          * our reservation.
4160          */
4161         if (used <= space_info->total_bytes) {
4162                 if (used + orig_bytes <= space_info->total_bytes) {
4163                         space_info->bytes_may_use += orig_bytes;
4164                         trace_btrfs_space_reservation(root->fs_info,
4165                                 "space_info", space_info->flags, orig_bytes, 1);
4166                         ret = 0;
4167                 } else {
4168                         /*
4169                          * Ok set num_bytes to orig_bytes since we aren't
4170                          * overocmmitted, this way we only try and reclaim what
4171                          * we need.
4172                          */
4173                         num_bytes = orig_bytes;
4174                 }
4175         } else {
4176                 /*
4177                  * Ok we're over committed, set num_bytes to the overcommitted
4178                  * amount plus the amount of bytes that we need for this
4179                  * reservation.
4180                  */
4181                 num_bytes = used - space_info->total_bytes +
4182                         (orig_bytes * 2);
4183         }
4184
4185         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4186                 space_info->bytes_may_use += orig_bytes;
4187                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4188                                               space_info->flags, orig_bytes,
4189                                               1);
4190                 ret = 0;
4191         }
4192
4193         /*
4194          * Couldn't make our reservation, save our place so while we're trying
4195          * to reclaim space we can actually use it instead of somebody else
4196          * stealing it from us.
4197          *
4198          * We make the other tasks wait for the flush only when we can flush
4199          * all things.
4200          */
4201         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4202                 flushing = true;
4203                 space_info->flush = 1;
4204         }
4205
4206         spin_unlock(&space_info->lock);
4207
4208         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4209                 goto out;
4210
4211         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4212                           flush_state);
4213         flush_state++;
4214
4215         /*
4216          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4217          * would happen. So skip delalloc flush.
4218          */
4219         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4220             (flush_state == FLUSH_DELALLOC ||
4221              flush_state == FLUSH_DELALLOC_WAIT))
4222                 flush_state = ALLOC_CHUNK;
4223
4224         if (!ret)
4225                 goto again;
4226         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4227                  flush_state < COMMIT_TRANS)
4228                 goto again;
4229         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4230                  flush_state <= COMMIT_TRANS)
4231                 goto again;
4232
4233 out:
4234         if (ret == -ENOSPC &&
4235             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4236                 struct btrfs_block_rsv *global_rsv =
4237                         &root->fs_info->global_block_rsv;
4238
4239                 if (block_rsv != global_rsv &&
4240                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4241                         ret = 0;
4242         }
4243         if (flushing) {
4244                 spin_lock(&space_info->lock);
4245                 space_info->flush = 0;
4246                 wake_up_all(&space_info->wait);
4247                 spin_unlock(&space_info->lock);
4248         }
4249         return ret;
4250 }
4251
4252 static struct btrfs_block_rsv *get_block_rsv(
4253                                         const struct btrfs_trans_handle *trans,
4254                                         const struct btrfs_root *root)
4255 {
4256         struct btrfs_block_rsv *block_rsv = NULL;
4257
4258         if (root->ref_cows)
4259                 block_rsv = trans->block_rsv;
4260
4261         if (root == root->fs_info->csum_root && trans->adding_csums)
4262                 block_rsv = trans->block_rsv;
4263
4264         if (!block_rsv)
4265                 block_rsv = root->block_rsv;
4266
4267         if (!block_rsv)
4268                 block_rsv = &root->fs_info->empty_block_rsv;
4269
4270         return block_rsv;
4271 }
4272
4273 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4274                                u64 num_bytes)
4275 {
4276         int ret = -ENOSPC;
4277         spin_lock(&block_rsv->lock);
4278         if (block_rsv->reserved >= num_bytes) {
4279                 block_rsv->reserved -= num_bytes;
4280                 if (block_rsv->reserved < block_rsv->size)
4281                         block_rsv->full = 0;
4282                 ret = 0;
4283         }
4284         spin_unlock(&block_rsv->lock);
4285         return ret;
4286 }
4287
4288 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4289                                 u64 num_bytes, int update_size)
4290 {
4291         spin_lock(&block_rsv->lock);
4292         block_rsv->reserved += num_bytes;
4293         if (update_size)
4294                 block_rsv->size += num_bytes;
4295         else if (block_rsv->reserved >= block_rsv->size)
4296                 block_rsv->full = 1;
4297         spin_unlock(&block_rsv->lock);
4298 }
4299
4300 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4301                                     struct btrfs_block_rsv *block_rsv,
4302                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4303 {
4304         struct btrfs_space_info *space_info = block_rsv->space_info;
4305
4306         spin_lock(&block_rsv->lock);
4307         if (num_bytes == (u64)-1)
4308                 num_bytes = block_rsv->size;
4309         block_rsv->size -= num_bytes;
4310         if (block_rsv->reserved >= block_rsv->size) {
4311                 num_bytes = block_rsv->reserved - block_rsv->size;
4312                 block_rsv->reserved = block_rsv->size;
4313                 block_rsv->full = 1;
4314         } else {
4315                 num_bytes = 0;
4316         }
4317         spin_unlock(&block_rsv->lock);
4318
4319         if (num_bytes > 0) {
4320                 if (dest) {
4321                         spin_lock(&dest->lock);
4322                         if (!dest->full) {
4323                                 u64 bytes_to_add;
4324
4325                                 bytes_to_add = dest->size - dest->reserved;
4326                                 bytes_to_add = min(num_bytes, bytes_to_add);
4327                                 dest->reserved += bytes_to_add;
4328                                 if (dest->reserved >= dest->size)
4329                                         dest->full = 1;
4330                                 num_bytes -= bytes_to_add;
4331                         }
4332                         spin_unlock(&dest->lock);
4333                 }
4334                 if (num_bytes) {
4335                         spin_lock(&space_info->lock);
4336                         space_info->bytes_may_use -= num_bytes;
4337                         trace_btrfs_space_reservation(fs_info, "space_info",
4338                                         space_info->flags, num_bytes, 0);
4339                         space_info->reservation_progress++;
4340                         spin_unlock(&space_info->lock);
4341                 }
4342         }
4343 }
4344
4345 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4346                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4347 {
4348         int ret;
4349
4350         ret = block_rsv_use_bytes(src, num_bytes);
4351         if (ret)
4352                 return ret;
4353
4354         block_rsv_add_bytes(dst, num_bytes, 1);
4355         return 0;
4356 }
4357
4358 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4359 {
4360         memset(rsv, 0, sizeof(*rsv));
4361         spin_lock_init(&rsv->lock);
4362         rsv->type = type;
4363 }
4364
4365 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4366                                               unsigned short type)
4367 {
4368         struct btrfs_block_rsv *block_rsv;
4369         struct btrfs_fs_info *fs_info = root->fs_info;
4370
4371         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4372         if (!block_rsv)
4373                 return NULL;
4374
4375         btrfs_init_block_rsv(block_rsv, type);
4376         block_rsv->space_info = __find_space_info(fs_info,
4377                                                   BTRFS_BLOCK_GROUP_METADATA);
4378         return block_rsv;
4379 }
4380
4381 void btrfs_free_block_rsv(struct btrfs_root *root,
4382                           struct btrfs_block_rsv *rsv)
4383 {
4384         if (!rsv)
4385                 return;
4386         btrfs_block_rsv_release(root, rsv, (u64)-1);
4387         kfree(rsv);
4388 }
4389
4390 int btrfs_block_rsv_add(struct btrfs_root *root,
4391                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4392                         enum btrfs_reserve_flush_enum flush)
4393 {
4394         int ret;
4395
4396         if (num_bytes == 0)
4397                 return 0;
4398
4399         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4400         if (!ret) {
4401                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4402                 return 0;
4403         }
4404
4405         return ret;
4406 }
4407
4408 int btrfs_block_rsv_check(struct btrfs_root *root,
4409                           struct btrfs_block_rsv *block_rsv, int min_factor)
4410 {
4411         u64 num_bytes = 0;
4412         int ret = -ENOSPC;
4413
4414         if (!block_rsv)
4415                 return 0;
4416
4417         spin_lock(&block_rsv->lock);
4418         num_bytes = div_factor(block_rsv->size, min_factor);
4419         if (block_rsv->reserved >= num_bytes)
4420                 ret = 0;
4421         spin_unlock(&block_rsv->lock);
4422
4423         return ret;
4424 }
4425
4426 int btrfs_block_rsv_refill(struct btrfs_root *root,
4427                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4428                            enum btrfs_reserve_flush_enum flush)
4429 {
4430         u64 num_bytes = 0;
4431         int ret = -ENOSPC;
4432
4433         if (!block_rsv)
4434                 return 0;
4435
4436         spin_lock(&block_rsv->lock);
4437         num_bytes = min_reserved;
4438         if (block_rsv->reserved >= num_bytes)
4439                 ret = 0;
4440         else
4441                 num_bytes -= block_rsv->reserved;
4442         spin_unlock(&block_rsv->lock);
4443
4444         if (!ret)
4445                 return 0;
4446
4447         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4448         if (!ret) {
4449                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4450                 return 0;
4451         }
4452
4453         return ret;
4454 }
4455
4456 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4457                             struct btrfs_block_rsv *dst_rsv,
4458                             u64 num_bytes)
4459 {
4460         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4461 }
4462
4463 void btrfs_block_rsv_release(struct btrfs_root *root,
4464                              struct btrfs_block_rsv *block_rsv,
4465                              u64 num_bytes)
4466 {
4467         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4468         if (global_rsv->full || global_rsv == block_rsv ||
4469             block_rsv->space_info != global_rsv->space_info)
4470                 global_rsv = NULL;
4471         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4472                                 num_bytes);
4473 }
4474
4475 /*
4476  * helper to calculate size of global block reservation.
4477  * the desired value is sum of space used by extent tree,
4478  * checksum tree and root tree
4479  */
4480 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4481 {
4482         struct btrfs_space_info *sinfo;
4483         u64 num_bytes;
4484         u64 meta_used;
4485         u64 data_used;
4486         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4487
4488         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4489         spin_lock(&sinfo->lock);
4490         data_used = sinfo->bytes_used;
4491         spin_unlock(&sinfo->lock);
4492
4493         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4494         spin_lock(&sinfo->lock);
4495         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4496                 data_used = 0;
4497         meta_used = sinfo->bytes_used;
4498         spin_unlock(&sinfo->lock);
4499
4500         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4501                     csum_size * 2;
4502         num_bytes += div64_u64(data_used + meta_used, 50);
4503
4504         if (num_bytes * 3 > meta_used)
4505                 num_bytes = div64_u64(meta_used, 3);
4506
4507         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4508 }
4509
4510 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4511 {
4512         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4513         struct btrfs_space_info *sinfo = block_rsv->space_info;
4514         u64 num_bytes;
4515
4516         num_bytes = calc_global_metadata_size(fs_info);
4517
4518         spin_lock(&sinfo->lock);
4519         spin_lock(&block_rsv->lock);
4520
4521         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4522
4523         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4524                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4525                     sinfo->bytes_may_use;
4526
4527         if (sinfo->total_bytes > num_bytes) {
4528                 num_bytes = sinfo->total_bytes - num_bytes;
4529                 block_rsv->reserved += num_bytes;
4530                 sinfo->bytes_may_use += num_bytes;
4531                 trace_btrfs_space_reservation(fs_info, "space_info",
4532                                       sinfo->flags, num_bytes, 1);
4533         }
4534
4535         if (block_rsv->reserved >= block_rsv->size) {
4536                 num_bytes = block_rsv->reserved - block_rsv->size;
4537                 sinfo->bytes_may_use -= num_bytes;
4538                 trace_btrfs_space_reservation(fs_info, "space_info",
4539                                       sinfo->flags, num_bytes, 0);
4540                 sinfo->reservation_progress++;
4541                 block_rsv->reserved = block_rsv->size;
4542                 block_rsv->full = 1;
4543         }
4544
4545         spin_unlock(&block_rsv->lock);
4546         spin_unlock(&sinfo->lock);
4547 }
4548
4549 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4550 {
4551         struct btrfs_space_info *space_info;
4552
4553         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4554         fs_info->chunk_block_rsv.space_info = space_info;
4555
4556         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4557         fs_info->global_block_rsv.space_info = space_info;
4558         fs_info->delalloc_block_rsv.space_info = space_info;
4559         fs_info->trans_block_rsv.space_info = space_info;
4560         fs_info->empty_block_rsv.space_info = space_info;
4561         fs_info->delayed_block_rsv.space_info = space_info;
4562
4563         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4564         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4565         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4566         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4567         if (fs_info->quota_root)
4568                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4569         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4570
4571         update_global_block_rsv(fs_info);
4572 }
4573
4574 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4575 {
4576         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4577                                 (u64)-1);
4578         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4579         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4580         WARN_ON(fs_info->trans_block_rsv.size > 0);
4581         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4582         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4583         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4584         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4585         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4586 }
4587
4588 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4589                                   struct btrfs_root *root)
4590 {
4591         if (!trans->block_rsv)
4592                 return;
4593
4594         if (!trans->bytes_reserved)
4595                 return;
4596
4597         trace_btrfs_space_reservation(root->fs_info, "transaction",
4598                                       trans->transid, trans->bytes_reserved, 0);
4599         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4600         trans->bytes_reserved = 0;
4601 }
4602
4603 /* Can only return 0 or -ENOSPC */
4604 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4605                                   struct inode *inode)
4606 {
4607         struct btrfs_root *root = BTRFS_I(inode)->root;
4608         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4609         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4610
4611         /*
4612          * We need to hold space in order to delete our orphan item once we've
4613          * added it, so this takes the reservation so we can release it later
4614          * when we are truly done with the orphan item.
4615          */
4616         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4617         trace_btrfs_space_reservation(root->fs_info, "orphan",
4618                                       btrfs_ino(inode), num_bytes, 1);
4619         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4620 }
4621
4622 void btrfs_orphan_release_metadata(struct inode *inode)
4623 {
4624         struct btrfs_root *root = BTRFS_I(inode)->root;
4625         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4626         trace_btrfs_space_reservation(root->fs_info, "orphan",
4627                                       btrfs_ino(inode), num_bytes, 0);
4628         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4629 }
4630
4631 /*
4632  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4633  * root: the root of the parent directory
4634  * rsv: block reservation
4635  * items: the number of items that we need do reservation
4636  * qgroup_reserved: used to return the reserved size in qgroup
4637  *
4638  * This function is used to reserve the space for snapshot/subvolume
4639  * creation and deletion. Those operations are different with the
4640  * common file/directory operations, they change two fs/file trees
4641  * and root tree, the number of items that the qgroup reserves is
4642  * different with the free space reservation. So we can not use
4643  * the space reseravtion mechanism in start_transaction().
4644  */
4645 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4646                                      struct btrfs_block_rsv *rsv,
4647                                      int items,
4648                                      u64 *qgroup_reserved)
4649 {
4650         u64 num_bytes;
4651         int ret;
4652
4653         if (root->fs_info->quota_enabled) {
4654                 /* One for parent inode, two for dir entries */
4655                 num_bytes = 3 * root->leafsize;
4656                 ret = btrfs_qgroup_reserve(root, num_bytes);
4657                 if (ret)
4658                         return ret;
4659         } else {
4660                 num_bytes = 0;
4661         }
4662
4663         *qgroup_reserved = num_bytes;
4664
4665         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4666         rsv->space_info = __find_space_info(root->fs_info,
4667                                             BTRFS_BLOCK_GROUP_METADATA);
4668         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4669                                   BTRFS_RESERVE_FLUSH_ALL);
4670         if (ret) {
4671                 if (*qgroup_reserved)
4672                         btrfs_qgroup_free(root, *qgroup_reserved);
4673         }
4674
4675         return ret;
4676 }
4677
4678 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4679                                       struct btrfs_block_rsv *rsv,
4680                                       u64 qgroup_reserved)
4681 {
4682         btrfs_block_rsv_release(root, rsv, (u64)-1);
4683         if (qgroup_reserved)
4684                 btrfs_qgroup_free(root, qgroup_reserved);
4685 }
4686
4687 /**
4688  * drop_outstanding_extent - drop an outstanding extent
4689  * @inode: the inode we're dropping the extent for
4690  *
4691  * This is called when we are freeing up an outstanding extent, either called
4692  * after an error or after an extent is written.  This will return the number of
4693  * reserved extents that need to be freed.  This must be called with
4694  * BTRFS_I(inode)->lock held.
4695  */
4696 static unsigned drop_outstanding_extent(struct inode *inode)
4697 {
4698         unsigned drop_inode_space = 0;
4699         unsigned dropped_extents = 0;
4700
4701         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4702         BTRFS_I(inode)->outstanding_extents--;
4703
4704         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4705             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4706                                &BTRFS_I(inode)->runtime_flags))
4707                 drop_inode_space = 1;
4708
4709         /*
4710          * If we have more or the same amount of outsanding extents than we have
4711          * reserved then we need to leave the reserved extents count alone.
4712          */
4713         if (BTRFS_I(inode)->outstanding_extents >=
4714             BTRFS_I(inode)->reserved_extents)
4715                 return drop_inode_space;
4716
4717         dropped_extents = BTRFS_I(inode)->reserved_extents -
4718                 BTRFS_I(inode)->outstanding_extents;
4719         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4720         return dropped_extents + drop_inode_space;
4721 }
4722
4723 /**
4724  * calc_csum_metadata_size - return the amount of metada space that must be
4725  *      reserved/free'd for the given bytes.
4726  * @inode: the inode we're manipulating
4727  * @num_bytes: the number of bytes in question
4728  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4729  *
4730  * This adjusts the number of csum_bytes in the inode and then returns the
4731  * correct amount of metadata that must either be reserved or freed.  We
4732  * calculate how many checksums we can fit into one leaf and then divide the
4733  * number of bytes that will need to be checksumed by this value to figure out
4734  * how many checksums will be required.  If we are adding bytes then the number
4735  * may go up and we will return the number of additional bytes that must be
4736  * reserved.  If it is going down we will return the number of bytes that must
4737  * be freed.
4738  *
4739  * This must be called with BTRFS_I(inode)->lock held.
4740  */
4741 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4742                                    int reserve)
4743 {
4744         struct btrfs_root *root = BTRFS_I(inode)->root;
4745         u64 csum_size;
4746         int num_csums_per_leaf;
4747         int num_csums;
4748         int old_csums;
4749
4750         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4751             BTRFS_I(inode)->csum_bytes == 0)
4752                 return 0;
4753
4754         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4755         if (reserve)
4756                 BTRFS_I(inode)->csum_bytes += num_bytes;
4757         else
4758                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4759         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4760         num_csums_per_leaf = (int)div64_u64(csum_size,
4761                                             sizeof(struct btrfs_csum_item) +
4762                                             sizeof(struct btrfs_disk_key));
4763         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4764         num_csums = num_csums + num_csums_per_leaf - 1;
4765         num_csums = num_csums / num_csums_per_leaf;
4766
4767         old_csums = old_csums + num_csums_per_leaf - 1;
4768         old_csums = old_csums / num_csums_per_leaf;
4769
4770         /* No change, no need to reserve more */
4771         if (old_csums == num_csums)
4772                 return 0;
4773
4774         if (reserve)
4775                 return btrfs_calc_trans_metadata_size(root,
4776                                                       num_csums - old_csums);
4777
4778         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4779 }
4780
4781 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4782 {
4783         struct btrfs_root *root = BTRFS_I(inode)->root;
4784         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4785         u64 to_reserve = 0;
4786         u64 csum_bytes;
4787         unsigned nr_extents = 0;
4788         int extra_reserve = 0;
4789         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
4790         int ret = 0;
4791         bool delalloc_lock = true;
4792         u64 to_free = 0;
4793         unsigned dropped;
4794
4795         /* If we are a free space inode we need to not flush since we will be in
4796          * the middle of a transaction commit.  We also don't need the delalloc
4797          * mutex since we won't race with anybody.  We need this mostly to make
4798          * lockdep shut its filthy mouth.
4799          */
4800         if (btrfs_is_free_space_inode(inode)) {
4801                 flush = BTRFS_RESERVE_NO_FLUSH;
4802                 delalloc_lock = false;
4803         }
4804
4805         if (flush != BTRFS_RESERVE_NO_FLUSH &&
4806             btrfs_transaction_in_commit(root->fs_info))
4807                 schedule_timeout(1);
4808
4809         if (delalloc_lock)
4810                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4811
4812         num_bytes = ALIGN(num_bytes, root->sectorsize);
4813
4814         spin_lock(&BTRFS_I(inode)->lock);
4815         BTRFS_I(inode)->outstanding_extents++;
4816
4817         if (BTRFS_I(inode)->outstanding_extents >
4818             BTRFS_I(inode)->reserved_extents)
4819                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4820                         BTRFS_I(inode)->reserved_extents;
4821
4822         /*
4823          * Add an item to reserve for updating the inode when we complete the
4824          * delalloc io.
4825          */
4826         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4827                       &BTRFS_I(inode)->runtime_flags)) {
4828                 nr_extents++;
4829                 extra_reserve = 1;
4830         }
4831
4832         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4833         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4834         csum_bytes = BTRFS_I(inode)->csum_bytes;
4835         spin_unlock(&BTRFS_I(inode)->lock);
4836
4837         if (root->fs_info->quota_enabled) {
4838                 ret = btrfs_qgroup_reserve(root, num_bytes +
4839                                            nr_extents * root->leafsize);
4840                 if (ret)
4841                         goto out_fail;
4842         }
4843
4844         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4845         if (unlikely(ret)) {
4846                 if (root->fs_info->quota_enabled)
4847                         btrfs_qgroup_free(root, num_bytes +
4848                                                 nr_extents * root->leafsize);
4849                 goto out_fail;
4850         }
4851
4852         spin_lock(&BTRFS_I(inode)->lock);
4853         if (extra_reserve) {
4854                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4855                         &BTRFS_I(inode)->runtime_flags);
4856                 nr_extents--;
4857         }
4858         BTRFS_I(inode)->reserved_extents += nr_extents;
4859         spin_unlock(&BTRFS_I(inode)->lock);
4860
4861         if (delalloc_lock)
4862                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4863
4864         if (to_reserve)
4865                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4866                                               btrfs_ino(inode), to_reserve, 1);
4867         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4868
4869         return 0;
4870
4871 out_fail:
4872         spin_lock(&BTRFS_I(inode)->lock);
4873         dropped = drop_outstanding_extent(inode);
4874         /*
4875          * If the inodes csum_bytes is the same as the original
4876          * csum_bytes then we know we haven't raced with any free()ers
4877          * so we can just reduce our inodes csum bytes and carry on.
4878          */
4879         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
4880                 calc_csum_metadata_size(inode, num_bytes, 0);
4881         } else {
4882                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
4883                 u64 bytes;
4884
4885                 /*
4886                  * This is tricky, but first we need to figure out how much we
4887                  * free'd from any free-ers that occured during this
4888                  * reservation, so we reset ->csum_bytes to the csum_bytes
4889                  * before we dropped our lock, and then call the free for the
4890                  * number of bytes that were freed while we were trying our
4891                  * reservation.
4892                  */
4893                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
4894                 BTRFS_I(inode)->csum_bytes = csum_bytes;
4895                 to_free = calc_csum_metadata_size(inode, bytes, 0);
4896
4897
4898                 /*
4899                  * Now we need to see how much we would have freed had we not
4900                  * been making this reservation and our ->csum_bytes were not
4901                  * artificially inflated.
4902                  */
4903                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
4904                 bytes = csum_bytes - orig_csum_bytes;
4905                 bytes = calc_csum_metadata_size(inode, bytes, 0);
4906
4907                 /*
4908                  * Now reset ->csum_bytes to what it should be.  If bytes is
4909                  * more than to_free then we would have free'd more space had we
4910                  * not had an artificially high ->csum_bytes, so we need to free
4911                  * the remainder.  If bytes is the same or less then we don't
4912                  * need to do anything, the other free-ers did the correct
4913                  * thing.
4914                  */
4915                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
4916                 if (bytes > to_free)
4917                         to_free = bytes - to_free;
4918                 else
4919                         to_free = 0;
4920         }
4921         spin_unlock(&BTRFS_I(inode)->lock);
4922         if (dropped)
4923                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4924
4925         if (to_free) {
4926                 btrfs_block_rsv_release(root, block_rsv, to_free);
4927                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
4928                                               btrfs_ino(inode), to_free, 0);
4929         }
4930         if (delalloc_lock)
4931                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4932         return ret;
4933 }
4934
4935 /**
4936  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4937  * @inode: the inode to release the reservation for
4938  * @num_bytes: the number of bytes we're releasing
4939  *
4940  * This will release the metadata reservation for an inode.  This can be called
4941  * once we complete IO for a given set of bytes to release their metadata
4942  * reservations.
4943  */
4944 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4945 {
4946         struct btrfs_root *root = BTRFS_I(inode)->root;
4947         u64 to_free = 0;
4948         unsigned dropped;
4949
4950         num_bytes = ALIGN(num_bytes, root->sectorsize);
4951         spin_lock(&BTRFS_I(inode)->lock);
4952         dropped = drop_outstanding_extent(inode);
4953
4954         if (num_bytes)
4955                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4956         spin_unlock(&BTRFS_I(inode)->lock);
4957         if (dropped > 0)
4958                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4959
4960         trace_btrfs_space_reservation(root->fs_info, "delalloc",
4961                                       btrfs_ino(inode), to_free, 0);
4962         if (root->fs_info->quota_enabled) {
4963                 btrfs_qgroup_free(root, num_bytes +
4964                                         dropped * root->leafsize);
4965         }
4966
4967         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4968                                 to_free);
4969 }
4970
4971 /**
4972  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4973  * @inode: inode we're writing to
4974  * @num_bytes: the number of bytes we want to allocate
4975  *
4976  * This will do the following things
4977  *
4978  * o reserve space in the data space info for num_bytes
4979  * o reserve space in the metadata space info based on number of outstanding
4980  *   extents and how much csums will be needed
4981  * o add to the inodes ->delalloc_bytes
4982  * o add it to the fs_info's delalloc inodes list.
4983  *
4984  * This will return 0 for success and -ENOSPC if there is no space left.
4985  */
4986 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4987 {
4988         int ret;
4989
4990         ret = btrfs_check_data_free_space(inode, num_bytes);
4991         if (ret)
4992                 return ret;
4993
4994         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4995         if (ret) {
4996                 btrfs_free_reserved_data_space(inode, num_bytes);
4997                 return ret;
4998         }
4999
5000         return 0;
5001 }
5002
5003 /**
5004  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5005  * @inode: inode we're releasing space for
5006  * @num_bytes: the number of bytes we want to free up
5007  *
5008  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5009  * called in the case that we don't need the metadata AND data reservations
5010  * anymore.  So if there is an error or we insert an inline extent.
5011  *
5012  * This function will release the metadata space that was not used and will
5013  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5014  * list if there are no delalloc bytes left.
5015  */
5016 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5017 {
5018         btrfs_delalloc_release_metadata(inode, num_bytes);
5019         btrfs_free_reserved_data_space(inode, num_bytes);
5020 }
5021
5022 static int update_block_group(struct btrfs_root *root,
5023                               u64 bytenr, u64 num_bytes, int alloc)
5024 {
5025         struct btrfs_block_group_cache *cache = NULL;
5026         struct btrfs_fs_info *info = root->fs_info;
5027         u64 total = num_bytes;
5028         u64 old_val;
5029         u64 byte_in_group;
5030         int factor;
5031
5032         /* block accounting for super block */
5033         spin_lock(&info->delalloc_lock);
5034         old_val = btrfs_super_bytes_used(info->super_copy);
5035         if (alloc)
5036                 old_val += num_bytes;
5037         else
5038                 old_val -= num_bytes;
5039         btrfs_set_super_bytes_used(info->super_copy, old_val);
5040         spin_unlock(&info->delalloc_lock);
5041
5042         while (total) {
5043                 cache = btrfs_lookup_block_group(info, bytenr);
5044                 if (!cache)
5045                         return -ENOENT;
5046                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5047                                     BTRFS_BLOCK_GROUP_RAID1 |
5048                                     BTRFS_BLOCK_GROUP_RAID10))
5049                         factor = 2;
5050                 else
5051                         factor = 1;
5052                 /*
5053                  * If this block group has free space cache written out, we
5054                  * need to make sure to load it if we are removing space.  This
5055                  * is because we need the unpinning stage to actually add the
5056                  * space back to the block group, otherwise we will leak space.
5057                  */
5058                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5059                         cache_block_group(cache, 1);
5060
5061                 byte_in_group = bytenr - cache->key.objectid;
5062                 WARN_ON(byte_in_group > cache->key.offset);
5063
5064                 spin_lock(&cache->space_info->lock);
5065                 spin_lock(&cache->lock);
5066
5067                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5068                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5069                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5070
5071                 cache->dirty = 1;
5072                 old_val = btrfs_block_group_used(&cache->item);
5073                 num_bytes = min(total, cache->key.offset - byte_in_group);
5074                 if (alloc) {
5075                         old_val += num_bytes;
5076                         btrfs_set_block_group_used(&cache->item, old_val);
5077                         cache->reserved -= num_bytes;
5078                         cache->space_info->bytes_reserved -= num_bytes;
5079                         cache->space_info->bytes_used += num_bytes;
5080                         cache->space_info->disk_used += num_bytes * factor;
5081                         spin_unlock(&cache->lock);
5082                         spin_unlock(&cache->space_info->lock);
5083                 } else {
5084                         old_val -= num_bytes;
5085                         btrfs_set_block_group_used(&cache->item, old_val);
5086                         cache->pinned += num_bytes;
5087                         cache->space_info->bytes_pinned += num_bytes;
5088                         cache->space_info->bytes_used -= num_bytes;
5089                         cache->space_info->disk_used -= num_bytes * factor;
5090                         spin_unlock(&cache->lock);
5091                         spin_unlock(&cache->space_info->lock);
5092
5093                         set_extent_dirty(info->pinned_extents,
5094                                          bytenr, bytenr + num_bytes - 1,
5095                                          GFP_NOFS | __GFP_NOFAIL);
5096                 }
5097                 btrfs_put_block_group(cache);
5098                 total -= num_bytes;
5099                 bytenr += num_bytes;
5100         }
5101         return 0;
5102 }
5103
5104 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5105 {
5106         struct btrfs_block_group_cache *cache;
5107         u64 bytenr;
5108
5109         spin_lock(&root->fs_info->block_group_cache_lock);
5110         bytenr = root->fs_info->first_logical_byte;
5111         spin_unlock(&root->fs_info->block_group_cache_lock);
5112
5113         if (bytenr < (u64)-1)
5114                 return bytenr;
5115
5116         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5117         if (!cache)
5118                 return 0;
5119
5120         bytenr = cache->key.objectid;
5121         btrfs_put_block_group(cache);
5122
5123         return bytenr;
5124 }
5125
5126 static int pin_down_extent(struct btrfs_root *root,
5127                            struct btrfs_block_group_cache *cache,
5128                            u64 bytenr, u64 num_bytes, int reserved)
5129 {
5130         spin_lock(&cache->space_info->lock);
5131         spin_lock(&cache->lock);
5132         cache->pinned += num_bytes;
5133         cache->space_info->bytes_pinned += num_bytes;
5134         if (reserved) {
5135                 cache->reserved -= num_bytes;
5136                 cache->space_info->bytes_reserved -= num_bytes;
5137         }
5138         spin_unlock(&cache->lock);
5139         spin_unlock(&cache->space_info->lock);
5140
5141         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5142                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5143         return 0;
5144 }
5145
5146 /*
5147  * this function must be called within transaction
5148  */
5149 int btrfs_pin_extent(struct btrfs_root *root,
5150                      u64 bytenr, u64 num_bytes, int reserved)
5151 {
5152         struct btrfs_block_group_cache *cache;
5153
5154         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5155         BUG_ON(!cache); /* Logic error */
5156
5157         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5158
5159         btrfs_put_block_group(cache);
5160         return 0;
5161 }
5162
5163 /*
5164  * this function must be called within transaction
5165  */
5166 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5167                                     u64 bytenr, u64 num_bytes)
5168 {
5169         struct btrfs_block_group_cache *cache;
5170         int ret;
5171
5172         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5173         if (!cache)
5174                 return -EINVAL;
5175
5176         /*
5177          * pull in the free space cache (if any) so that our pin
5178          * removes the free space from the cache.  We have load_only set
5179          * to one because the slow code to read in the free extents does check
5180          * the pinned extents.
5181          */
5182         cache_block_group(cache, 1);
5183
5184         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5185
5186         /* remove us from the free space cache (if we're there at all) */
5187         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5188         btrfs_put_block_group(cache);
5189         return ret;
5190 }
5191
5192 /**
5193  * btrfs_update_reserved_bytes - update the block_group and space info counters
5194  * @cache:      The cache we are manipulating
5195  * @num_bytes:  The number of bytes in question
5196  * @reserve:    One of the reservation enums
5197  *
5198  * This is called by the allocator when it reserves space, or by somebody who is
5199  * freeing space that was never actually used on disk.  For example if you
5200  * reserve some space for a new leaf in transaction A and before transaction A
5201  * commits you free that leaf, you call this with reserve set to 0 in order to
5202  * clear the reservation.
5203  *
5204  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5205  * ENOSPC accounting.  For data we handle the reservation through clearing the
5206  * delalloc bits in the io_tree.  We have to do this since we could end up
5207  * allocating less disk space for the amount of data we have reserved in the
5208  * case of compression.
5209  *
5210  * If this is a reservation and the block group has become read only we cannot
5211  * make the reservation and return -EAGAIN, otherwise this function always
5212  * succeeds.
5213  */
5214 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5215                                        u64 num_bytes, int reserve)
5216 {
5217         struct btrfs_space_info *space_info = cache->space_info;
5218         int ret = 0;
5219
5220         spin_lock(&space_info->lock);
5221         spin_lock(&cache->lock);
5222         if (reserve != RESERVE_FREE) {
5223                 if (cache->ro) {
5224                         ret = -EAGAIN;
5225                 } else {
5226                         cache->reserved += num_bytes;
5227                         space_info->bytes_reserved += num_bytes;
5228                         if (reserve == RESERVE_ALLOC) {
5229                                 trace_btrfs_space_reservation(cache->fs_info,
5230                                                 "space_info", space_info->flags,
5231                                                 num_bytes, 0);
5232                                 space_info->bytes_may_use -= num_bytes;
5233                         }
5234                 }
5235         } else {
5236                 if (cache->ro)
5237                         space_info->bytes_readonly += num_bytes;
5238                 cache->reserved -= num_bytes;
5239                 space_info->bytes_reserved -= num_bytes;
5240                 space_info->reservation_progress++;
5241         }
5242         spin_unlock(&cache->lock);
5243         spin_unlock(&space_info->lock);
5244         return ret;
5245 }
5246
5247 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5248                                 struct btrfs_root *root)
5249 {
5250         struct btrfs_fs_info *fs_info = root->fs_info;
5251         struct btrfs_caching_control *next;
5252         struct btrfs_caching_control *caching_ctl;
5253         struct btrfs_block_group_cache *cache;
5254
5255         down_write(&fs_info->extent_commit_sem);
5256
5257         list_for_each_entry_safe(caching_ctl, next,
5258                                  &fs_info->caching_block_groups, list) {
5259                 cache = caching_ctl->block_group;
5260                 if (block_group_cache_done(cache)) {
5261                         cache->last_byte_to_unpin = (u64)-1;
5262                         list_del_init(&caching_ctl->list);
5263                         put_caching_control(caching_ctl);
5264                 } else {
5265                         cache->last_byte_to_unpin = caching_ctl->progress;
5266                 }
5267         }
5268
5269         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5270                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5271         else
5272                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5273
5274         up_write(&fs_info->extent_commit_sem);
5275
5276         update_global_block_rsv(fs_info);
5277 }
5278
5279 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5280 {
5281         struct btrfs_fs_info *fs_info = root->fs_info;
5282         struct btrfs_block_group_cache *cache = NULL;
5283         struct btrfs_space_info *space_info;
5284         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5285         u64 len;
5286         bool readonly;
5287
5288         while (start <= end) {
5289                 readonly = false;
5290                 if (!cache ||
5291                     start >= cache->key.objectid + cache->key.offset) {
5292                         if (cache)
5293                                 btrfs_put_block_group(cache);
5294                         cache = btrfs_lookup_block_group(fs_info, start);
5295                         BUG_ON(!cache); /* Logic error */
5296                 }
5297
5298                 len = cache->key.objectid + cache->key.offset - start;
5299                 len = min(len, end + 1 - start);
5300
5301                 if (start < cache->last_byte_to_unpin) {
5302                         len = min(len, cache->last_byte_to_unpin - start);
5303                         btrfs_add_free_space(cache, start, len);
5304                 }
5305
5306                 start += len;
5307                 space_info = cache->space_info;
5308
5309                 spin_lock(&space_info->lock);
5310                 spin_lock(&cache->lock);
5311                 cache->pinned -= len;
5312                 space_info->bytes_pinned -= len;
5313                 if (cache->ro) {
5314                         space_info->bytes_readonly += len;
5315                         readonly = true;
5316                 }
5317                 spin_unlock(&cache->lock);
5318                 if (!readonly && global_rsv->space_info == space_info) {
5319                         spin_lock(&global_rsv->lock);
5320                         if (!global_rsv->full) {
5321                                 len = min(len, global_rsv->size -
5322                                           global_rsv->reserved);
5323                                 global_rsv->reserved += len;
5324                                 space_info->bytes_may_use += len;
5325                                 if (global_rsv->reserved >= global_rsv->size)
5326                                         global_rsv->full = 1;
5327                         }
5328                         spin_unlock(&global_rsv->lock);
5329                 }
5330                 spin_unlock(&space_info->lock);
5331         }
5332
5333         if (cache)
5334                 btrfs_put_block_group(cache);
5335         return 0;
5336 }
5337
5338 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5339                                struct btrfs_root *root)
5340 {
5341         struct btrfs_fs_info *fs_info = root->fs_info;
5342         struct extent_io_tree *unpin;
5343         u64 start;
5344         u64 end;
5345         int ret;
5346
5347         if (trans->aborted)
5348                 return 0;
5349
5350         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5351                 unpin = &fs_info->freed_extents[1];
5352         else
5353                 unpin = &fs_info->freed_extents[0];
5354
5355         while (1) {
5356                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5357                                             EXTENT_DIRTY, NULL);
5358                 if (ret)
5359                         break;
5360
5361                 if (btrfs_test_opt(root, DISCARD))
5362                         ret = btrfs_discard_extent(root, start,
5363                                                    end + 1 - start, NULL);
5364
5365                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5366                 unpin_extent_range(root, start, end);
5367                 cond_resched();
5368         }
5369
5370         return 0;
5371 }
5372
5373 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5374                                 struct btrfs_root *root,
5375                                 u64 bytenr, u64 num_bytes, u64 parent,
5376                                 u64 root_objectid, u64 owner_objectid,
5377                                 u64 owner_offset, int refs_to_drop,
5378                                 struct btrfs_delayed_extent_op *extent_op)
5379 {
5380         struct btrfs_key key;
5381         struct btrfs_path *path;
5382         struct btrfs_fs_info *info = root->fs_info;
5383         struct btrfs_root *extent_root = info->extent_root;
5384         struct extent_buffer *leaf;
5385         struct btrfs_extent_item *ei;
5386         struct btrfs_extent_inline_ref *iref;
5387         int ret;
5388         int is_data;
5389         int extent_slot = 0;
5390         int found_extent = 0;
5391         int num_to_del = 1;
5392         u32 item_size;
5393         u64 refs;
5394         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5395                                                  SKINNY_METADATA);
5396
5397         path = btrfs_alloc_path();
5398         if (!path)
5399                 return -ENOMEM;
5400
5401         path->reada = 1;
5402         path->leave_spinning = 1;
5403
5404         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5405         BUG_ON(!is_data && refs_to_drop != 1);
5406
5407         if (is_data)
5408                 skinny_metadata = 0;
5409
5410         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5411                                     bytenr, num_bytes, parent,
5412                                     root_objectid, owner_objectid,
5413                                     owner_offset);
5414         if (ret == 0) {
5415                 extent_slot = path->slots[0];
5416                 while (extent_slot >= 0) {
5417                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5418                                               extent_slot);
5419                         if (key.objectid != bytenr)
5420                                 break;
5421                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5422                             key.offset == num_bytes) {
5423                                 found_extent = 1;
5424                                 break;
5425                         }
5426                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5427                             key.offset == owner_objectid) {
5428                                 found_extent = 1;
5429                                 break;
5430                         }
5431                         if (path->slots[0] - extent_slot > 5)
5432                                 break;
5433                         extent_slot--;
5434                 }
5435 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5436                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5437                 if (found_extent && item_size < sizeof(*ei))
5438                         found_extent = 0;
5439 #endif
5440                 if (!found_extent) {
5441                         BUG_ON(iref);
5442                         ret = remove_extent_backref(trans, extent_root, path,
5443                                                     NULL, refs_to_drop,
5444                                                     is_data);
5445                         if (ret) {
5446                                 btrfs_abort_transaction(trans, extent_root, ret);
5447                                 goto out;
5448                         }
5449                         btrfs_release_path(path);
5450                         path->leave_spinning = 1;
5451
5452                         key.objectid = bytenr;
5453                         key.type = BTRFS_EXTENT_ITEM_KEY;
5454                         key.offset = num_bytes;
5455
5456                         if (!is_data && skinny_metadata) {
5457                                 key.type = BTRFS_METADATA_ITEM_KEY;
5458                                 key.offset = owner_objectid;
5459                         }
5460
5461                         ret = btrfs_search_slot(trans, extent_root,
5462                                                 &key, path, -1, 1);
5463                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5464                                 /*
5465                                  * Couldn't find our skinny metadata item,
5466                                  * see if we have ye olde extent item.
5467                                  */
5468                                 path->slots[0]--;
5469                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5470                                                       path->slots[0]);
5471                                 if (key.objectid == bytenr &&
5472                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5473                                     key.offset == num_bytes)
5474                                         ret = 0;
5475                         }
5476
5477                         if (ret > 0 && skinny_metadata) {
5478                                 skinny_metadata = false;
5479                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5480                                 key.offset = num_bytes;
5481                                 btrfs_release_path(path);
5482                                 ret = btrfs_search_slot(trans, extent_root,
5483                                                         &key, path, -1, 1);
5484                         }
5485
5486                         if (ret) {
5487                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5488                                         ret, (unsigned long long)bytenr);
5489                                 if (ret > 0)
5490                                         btrfs_print_leaf(extent_root,
5491                                                          path->nodes[0]);
5492                         }
5493                         if (ret < 0) {
5494                                 btrfs_abort_transaction(trans, extent_root, ret);
5495                                 goto out;
5496                         }
5497                         extent_slot = path->slots[0];
5498                 }
5499         } else if (ret == -ENOENT) {
5500                 btrfs_print_leaf(extent_root, path->nodes[0]);
5501                 WARN_ON(1);
5502                 btrfs_err(info,
5503                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5504                         (unsigned long long)bytenr,
5505                         (unsigned long long)parent,
5506                         (unsigned long long)root_objectid,
5507                         (unsigned long long)owner_objectid,
5508                         (unsigned long long)owner_offset);
5509         } else {
5510                 btrfs_abort_transaction(trans, extent_root, ret);
5511                 goto out;
5512         }
5513
5514         leaf = path->nodes[0];
5515         item_size = btrfs_item_size_nr(leaf, extent_slot);
5516 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5517         if (item_size < sizeof(*ei)) {
5518                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5519                 ret = convert_extent_item_v0(trans, extent_root, path,
5520                                              owner_objectid, 0);
5521                 if (ret < 0) {
5522                         btrfs_abort_transaction(trans, extent_root, ret);
5523                         goto out;
5524                 }
5525
5526                 btrfs_release_path(path);
5527                 path->leave_spinning = 1;
5528
5529                 key.objectid = bytenr;
5530                 key.type = BTRFS_EXTENT_ITEM_KEY;
5531                 key.offset = num_bytes;
5532
5533                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5534                                         -1, 1);
5535                 if (ret) {
5536                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5537                                 ret, (unsigned long long)bytenr);
5538                         btrfs_print_leaf(extent_root, path->nodes[0]);
5539                 }
5540                 if (ret < 0) {
5541                         btrfs_abort_transaction(trans, extent_root, ret);
5542                         goto out;
5543                 }
5544
5545                 extent_slot = path->slots[0];
5546                 leaf = path->nodes[0];
5547                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5548         }
5549 #endif
5550         BUG_ON(item_size < sizeof(*ei));
5551         ei = btrfs_item_ptr(leaf, extent_slot,
5552                             struct btrfs_extent_item);
5553         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
5554             key.type == BTRFS_EXTENT_ITEM_KEY) {
5555                 struct btrfs_tree_block_info *bi;
5556                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5557                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5558                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5559         }
5560
5561         refs = btrfs_extent_refs(leaf, ei);
5562         if (refs < refs_to_drop) {
5563                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
5564                           "for bytenr %Lu\n", refs_to_drop, refs, bytenr);
5565                 ret = -EINVAL;
5566                 btrfs_abort_transaction(trans, extent_root, ret);
5567                 goto out;
5568         }
5569         refs -= refs_to_drop;
5570
5571         if (refs > 0) {
5572                 if (extent_op)
5573                         __run_delayed_extent_op(extent_op, leaf, ei);
5574                 /*
5575                  * In the case of inline back ref, reference count will
5576                  * be updated by remove_extent_backref
5577                  */
5578                 if (iref) {
5579                         BUG_ON(!found_extent);
5580                 } else {
5581                         btrfs_set_extent_refs(leaf, ei, refs);
5582                         btrfs_mark_buffer_dirty(leaf);
5583                 }
5584                 if (found_extent) {
5585                         ret = remove_extent_backref(trans, extent_root, path,
5586                                                     iref, refs_to_drop,
5587                                                     is_data);
5588                         if (ret) {
5589                                 btrfs_abort_transaction(trans, extent_root, ret);
5590                                 goto out;
5591                         }
5592                 }
5593         } else {
5594                 if (found_extent) {
5595                         BUG_ON(is_data && refs_to_drop !=
5596                                extent_data_ref_count(root, path, iref));
5597                         if (iref) {
5598                                 BUG_ON(path->slots[0] != extent_slot);
5599                         } else {
5600                                 BUG_ON(path->slots[0] != extent_slot + 1);
5601                                 path->slots[0] = extent_slot;
5602                                 num_to_del = 2;
5603                         }
5604                 }
5605
5606                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5607                                       num_to_del);
5608                 if (ret) {
5609                         btrfs_abort_transaction(trans, extent_root, ret);
5610                         goto out;
5611                 }
5612                 btrfs_release_path(path);
5613
5614                 if (is_data) {
5615                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5616                         if (ret) {
5617                                 btrfs_abort_transaction(trans, extent_root, ret);
5618                                 goto out;
5619                         }
5620                 }
5621
5622                 ret = update_block_group(root, bytenr, num_bytes, 0);
5623                 if (ret) {
5624                         btrfs_abort_transaction(trans, extent_root, ret);
5625                         goto out;
5626                 }
5627         }
5628 out:
5629         btrfs_free_path(path);
5630         return ret;
5631 }
5632
5633 /*
5634  * when we free an block, it is possible (and likely) that we free the last
5635  * delayed ref for that extent as well.  This searches the delayed ref tree for
5636  * a given extent, and if there are no other delayed refs to be processed, it
5637  * removes it from the tree.
5638  */
5639 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5640                                       struct btrfs_root *root, u64 bytenr)
5641 {
5642         struct btrfs_delayed_ref_head *head;
5643         struct btrfs_delayed_ref_root *delayed_refs;
5644         struct btrfs_delayed_ref_node *ref;
5645         struct rb_node *node;
5646         int ret = 0;
5647
5648         delayed_refs = &trans->transaction->delayed_refs;
5649         spin_lock(&delayed_refs->lock);
5650         head = btrfs_find_delayed_ref_head(trans, bytenr);
5651         if (!head)
5652                 goto out;
5653
5654         node = rb_prev(&head->node.rb_node);
5655         if (!node)
5656                 goto out;
5657
5658         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5659
5660         /* there are still entries for this ref, we can't drop it */
5661         if (ref->bytenr == bytenr)
5662                 goto out;
5663
5664         if (head->extent_op) {
5665                 if (!head->must_insert_reserved)
5666                         goto out;
5667                 btrfs_free_delayed_extent_op(head->extent_op);
5668                 head->extent_op = NULL;
5669         }
5670
5671         /*
5672          * waiting for the lock here would deadlock.  If someone else has it
5673          * locked they are already in the process of dropping it anyway
5674          */
5675         if (!mutex_trylock(&head->mutex))
5676                 goto out;
5677
5678         /*
5679          * at this point we have a head with no other entries.  Go
5680          * ahead and process it.
5681          */
5682         head->node.in_tree = 0;
5683         rb_erase(&head->node.rb_node, &delayed_refs->root);
5684
5685         delayed_refs->num_entries--;
5686
5687         /*
5688          * we don't take a ref on the node because we're removing it from the
5689          * tree, so we just steal the ref the tree was holding.
5690          */
5691         delayed_refs->num_heads--;
5692         if (list_empty(&head->cluster))
5693                 delayed_refs->num_heads_ready--;
5694
5695         list_del_init(&head->cluster);
5696         spin_unlock(&delayed_refs->lock);
5697
5698         BUG_ON(head->extent_op);
5699         if (head->must_insert_reserved)
5700                 ret = 1;
5701
5702         mutex_unlock(&head->mutex);
5703         btrfs_put_delayed_ref(&head->node);
5704         return ret;
5705 out:
5706         spin_unlock(&delayed_refs->lock);
5707         return 0;
5708 }
5709
5710 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5711                            struct btrfs_root *root,
5712                            struct extent_buffer *buf,
5713                            u64 parent, int last_ref)
5714 {
5715         struct btrfs_block_group_cache *cache = NULL;
5716         int ret;
5717
5718         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5719                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5720                                         buf->start, buf->len,
5721                                         parent, root->root_key.objectid,
5722                                         btrfs_header_level(buf),
5723                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
5724                 BUG_ON(ret); /* -ENOMEM */
5725         }
5726
5727         if (!last_ref)
5728                 return;
5729
5730         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5731
5732         if (btrfs_header_generation(buf) == trans->transid) {
5733                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5734                         ret = check_ref_cleanup(trans, root, buf->start);
5735                         if (!ret)
5736                                 goto out;
5737                 }
5738
5739                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5740                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5741                         goto out;
5742                 }
5743
5744                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5745
5746                 btrfs_add_free_space(cache, buf->start, buf->len);
5747                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5748         }
5749 out:
5750         /*
5751          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5752          * anymore.
5753          */
5754         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5755         btrfs_put_block_group(cache);
5756 }
5757
5758 /* Can return -ENOMEM */
5759 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5760                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5761                       u64 owner, u64 offset, int for_cow)
5762 {
5763         int ret;
5764         struct btrfs_fs_info *fs_info = root->fs_info;
5765
5766         /*
5767          * tree log blocks never actually go into the extent allocation
5768          * tree, just update pinning info and exit early.
5769          */
5770         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5771                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5772                 /* unlocks the pinned mutex */
5773                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5774                 ret = 0;
5775         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5776                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5777                                         num_bytes,
5778                                         parent, root_objectid, (int)owner,
5779                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5780         } else {
5781                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5782                                                 num_bytes,
5783                                                 parent, root_objectid, owner,
5784                                                 offset, BTRFS_DROP_DELAYED_REF,
5785                                                 NULL, for_cow);
5786         }
5787         return ret;
5788 }
5789
5790 static u64 stripe_align(struct btrfs_root *root,
5791                         struct btrfs_block_group_cache *cache,
5792                         u64 val, u64 num_bytes)
5793 {
5794         u64 ret = ALIGN(val, root->stripesize);
5795         return ret;
5796 }
5797
5798 /*
5799  * when we wait for progress in the block group caching, its because
5800  * our allocation attempt failed at least once.  So, we must sleep
5801  * and let some progress happen before we try again.
5802  *
5803  * This function will sleep at least once waiting for new free space to
5804  * show up, and then it will check the block group free space numbers
5805  * for our min num_bytes.  Another option is to have it go ahead
5806  * and look in the rbtree for a free extent of a given size, but this
5807  * is a good start.
5808  */
5809 static noinline int
5810 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5811                                 u64 num_bytes)
5812 {
5813         struct btrfs_caching_control *caching_ctl;
5814
5815         caching_ctl = get_caching_control(cache);
5816         if (!caching_ctl)
5817                 return 0;
5818
5819         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5820                    (cache->free_space_ctl->free_space >= num_bytes));
5821
5822         put_caching_control(caching_ctl);
5823         return 0;
5824 }
5825
5826 static noinline int
5827 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5828 {
5829         struct btrfs_caching_control *caching_ctl;
5830
5831         caching_ctl = get_caching_control(cache);
5832         if (!caching_ctl)
5833                 return 0;
5834
5835         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5836
5837         put_caching_control(caching_ctl);
5838         return 0;
5839 }
5840
5841 int __get_raid_index(u64 flags)
5842 {
5843         if (flags & BTRFS_BLOCK_GROUP_RAID10)
5844                 return BTRFS_RAID_RAID10;
5845         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
5846                 return BTRFS_RAID_RAID1;
5847         else if (flags & BTRFS_BLOCK_GROUP_DUP)
5848                 return BTRFS_RAID_DUP;
5849         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
5850                 return BTRFS_RAID_RAID0;
5851         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
5852                 return BTRFS_RAID_RAID5;
5853         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
5854                 return BTRFS_RAID_RAID6;
5855
5856         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
5857 }
5858
5859 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5860 {
5861         return __get_raid_index(cache->flags);
5862 }
5863
5864 enum btrfs_loop_type {
5865         LOOP_CACHING_NOWAIT = 0,
5866         LOOP_CACHING_WAIT = 1,
5867         LOOP_ALLOC_CHUNK = 2,
5868         LOOP_NO_EMPTY_SIZE = 3,
5869 };
5870
5871 /*
5872  * walks the btree of allocated extents and find a hole of a given size.
5873  * The key ins is changed to record the hole:
5874  * ins->objectid == block start
5875  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5876  * ins->offset == number of blocks
5877  * Any available blocks before search_start are skipped.
5878  */
5879 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5880                                      struct btrfs_root *orig_root,
5881                                      u64 num_bytes, u64 empty_size,
5882                                      u64 hint_byte, struct btrfs_key *ins,
5883                                      u64 flags)
5884 {
5885         int ret = 0;
5886         struct btrfs_root *root = orig_root->fs_info->extent_root;
5887         struct btrfs_free_cluster *last_ptr = NULL;
5888         struct btrfs_block_group_cache *block_group = NULL;
5889         struct btrfs_block_group_cache *used_block_group;
5890         u64 search_start = 0;
5891         int empty_cluster = 2 * 1024 * 1024;
5892         struct btrfs_space_info *space_info;
5893         int loop = 0;
5894         int index = __get_raid_index(flags);
5895         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
5896                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5897         bool found_uncached_bg = false;
5898         bool failed_cluster_refill = false;
5899         bool failed_alloc = false;
5900         bool use_cluster = true;
5901         bool have_caching_bg = false;
5902
5903         WARN_ON(num_bytes < root->sectorsize);
5904         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5905         ins->objectid = 0;
5906         ins->offset = 0;
5907
5908         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
5909
5910         space_info = __find_space_info(root->fs_info, flags);
5911         if (!space_info) {
5912                 btrfs_err(root->fs_info, "No space info for %llu", flags);
5913                 return -ENOSPC;
5914         }
5915
5916         /*
5917          * If the space info is for both data and metadata it means we have a
5918          * small filesystem and we can't use the clustering stuff.
5919          */
5920         if (btrfs_mixed_space_info(space_info))
5921                 use_cluster = false;
5922
5923         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5924                 last_ptr = &root->fs_info->meta_alloc_cluster;
5925                 if (!btrfs_test_opt(root, SSD))
5926                         empty_cluster = 64 * 1024;
5927         }
5928
5929         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5930             btrfs_test_opt(root, SSD)) {
5931                 last_ptr = &root->fs_info->data_alloc_cluster;
5932         }
5933
5934         if (last_ptr) {
5935                 spin_lock(&last_ptr->lock);
5936                 if (last_ptr->block_group)
5937                         hint_byte = last_ptr->window_start;
5938                 spin_unlock(&last_ptr->lock);
5939         }
5940
5941         search_start = max(search_start, first_logical_byte(root, 0));
5942         search_start = max(search_start, hint_byte);
5943
5944         if (!last_ptr)
5945                 empty_cluster = 0;
5946
5947         if (search_start == hint_byte) {
5948                 block_group = btrfs_lookup_block_group(root->fs_info,
5949                                                        search_start);
5950                 used_block_group = block_group;
5951                 /*
5952                  * we don't want to use the block group if it doesn't match our
5953                  * allocation bits, or if its not cached.
5954                  *
5955                  * However if we are re-searching with an ideal block group
5956                  * picked out then we don't care that the block group is cached.
5957                  */
5958                 if (block_group && block_group_bits(block_group, flags) &&
5959                     block_group->cached != BTRFS_CACHE_NO) {
5960                         down_read(&space_info->groups_sem);
5961                         if (list_empty(&block_group->list) ||
5962                             block_group->ro) {
5963                                 /*
5964                                  * someone is removing this block group,
5965                                  * we can't jump into the have_block_group
5966                                  * target because our list pointers are not
5967                                  * valid
5968                                  */
5969                                 btrfs_put_block_group(block_group);
5970                                 up_read(&space_info->groups_sem);
5971                         } else {
5972                                 index = get_block_group_index(block_group);
5973                                 goto have_block_group;
5974                         }
5975                 } else if (block_group) {
5976                         btrfs_put_block_group(block_group);
5977                 }
5978         }
5979 search:
5980         have_caching_bg = false;
5981         down_read(&space_info->groups_sem);
5982         list_for_each_entry(block_group, &space_info->block_groups[index],
5983                             list) {
5984                 u64 offset;
5985                 int cached;
5986
5987                 used_block_group = block_group;
5988                 btrfs_get_block_group(block_group);
5989                 search_start = block_group->key.objectid;
5990
5991                 /*
5992                  * this can happen if we end up cycling through all the
5993                  * raid types, but we want to make sure we only allocate
5994                  * for the proper type.
5995                  */
5996                 if (!block_group_bits(block_group, flags)) {
5997                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5998                                 BTRFS_BLOCK_GROUP_RAID1 |
5999                                 BTRFS_BLOCK_GROUP_RAID5 |
6000                                 BTRFS_BLOCK_GROUP_RAID6 |
6001                                 BTRFS_BLOCK_GROUP_RAID10;
6002
6003                         /*
6004                          * if they asked for extra copies and this block group
6005                          * doesn't provide them, bail.  This does allow us to
6006                          * fill raid0 from raid1.
6007                          */
6008                         if ((flags & extra) && !(block_group->flags & extra))
6009                                 goto loop;
6010                 }
6011
6012 have_block_group:
6013                 cached = block_group_cache_done(block_group);
6014                 if (unlikely(!cached)) {
6015                         found_uncached_bg = true;
6016                         ret = cache_block_group(block_group, 0);
6017                         BUG_ON(ret < 0);
6018                         ret = 0;
6019                 }
6020
6021                 if (unlikely(block_group->ro))
6022                         goto loop;
6023
6024                 /*
6025                  * Ok we want to try and use the cluster allocator, so
6026                  * lets look there
6027                  */
6028                 if (last_ptr) {
6029                         unsigned long aligned_cluster;
6030                         /*
6031                          * the refill lock keeps out other
6032                          * people trying to start a new cluster
6033                          */
6034                         spin_lock(&last_ptr->refill_lock);
6035                         used_block_group = last_ptr->block_group;
6036                         if (used_block_group != block_group &&
6037                             (!used_block_group ||
6038                              used_block_group->ro ||
6039                              !block_group_bits(used_block_group, flags))) {
6040                                 used_block_group = block_group;
6041                                 goto refill_cluster;
6042                         }
6043
6044                         if (used_block_group != block_group)
6045                                 btrfs_get_block_group(used_block_group);
6046
6047                         offset = btrfs_alloc_from_cluster(used_block_group,
6048                           last_ptr, num_bytes, used_block_group->key.objectid);
6049                         if (offset) {
6050                                 /* we have a block, we're done */
6051                                 spin_unlock(&last_ptr->refill_lock);
6052                                 trace_btrfs_reserve_extent_cluster(root,
6053                                         block_group, search_start, num_bytes);
6054                                 goto checks;
6055                         }
6056
6057                         WARN_ON(last_ptr->block_group != used_block_group);
6058                         if (used_block_group != block_group) {
6059                                 btrfs_put_block_group(used_block_group);
6060                                 used_block_group = block_group;
6061                         }
6062 refill_cluster:
6063                         BUG_ON(used_block_group != block_group);
6064                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6065                          * set up a new clusters, so lets just skip it
6066                          * and let the allocator find whatever block
6067                          * it can find.  If we reach this point, we
6068                          * will have tried the cluster allocator
6069                          * plenty of times and not have found
6070                          * anything, so we are likely way too
6071                          * fragmented for the clustering stuff to find
6072                          * anything.
6073                          *
6074                          * However, if the cluster is taken from the
6075                          * current block group, release the cluster
6076                          * first, so that we stand a better chance of
6077                          * succeeding in the unclustered
6078                          * allocation.  */
6079                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6080                             last_ptr->block_group != block_group) {
6081                                 spin_unlock(&last_ptr->refill_lock);
6082                                 goto unclustered_alloc;
6083                         }
6084
6085                         /*
6086                          * this cluster didn't work out, free it and
6087                          * start over
6088                          */
6089                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6090
6091                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6092                                 spin_unlock(&last_ptr->refill_lock);
6093                                 goto unclustered_alloc;
6094                         }
6095
6096                         aligned_cluster = max_t(unsigned long,
6097                                                 empty_cluster + empty_size,
6098                                               block_group->full_stripe_len);
6099
6100                         /* allocate a cluster in this block group */
6101                         ret = btrfs_find_space_cluster(trans, root,
6102                                                block_group, last_ptr,
6103                                                search_start, num_bytes,
6104                                                aligned_cluster);
6105                         if (ret == 0) {
6106                                 /*
6107                                  * now pull our allocation out of this
6108                                  * cluster
6109                                  */
6110                                 offset = btrfs_alloc_from_cluster(block_group,
6111                                                   last_ptr, num_bytes,
6112                                                   search_start);
6113                                 if (offset) {
6114                                         /* we found one, proceed */
6115                                         spin_unlock(&last_ptr->refill_lock);
6116                                         trace_btrfs_reserve_extent_cluster(root,
6117                                                 block_group, search_start,
6118                                                 num_bytes);
6119                                         goto checks;
6120                                 }
6121                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6122                                    && !failed_cluster_refill) {
6123                                 spin_unlock(&last_ptr->refill_lock);
6124
6125                                 failed_cluster_refill = true;
6126                                 wait_block_group_cache_progress(block_group,
6127                                        num_bytes + empty_cluster + empty_size);
6128                                 goto have_block_group;
6129                         }
6130
6131                         /*
6132                          * at this point we either didn't find a cluster
6133                          * or we weren't able to allocate a block from our
6134                          * cluster.  Free the cluster we've been trying
6135                          * to use, and go to the next block group
6136                          */
6137                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6138                         spin_unlock(&last_ptr->refill_lock);
6139                         goto loop;
6140                 }
6141
6142 unclustered_alloc:
6143                 spin_lock(&block_group->free_space_ctl->tree_lock);
6144                 if (cached &&
6145                     block_group->free_space_ctl->free_space <
6146                     num_bytes + empty_cluster + empty_size) {
6147                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6148                         goto loop;
6149                 }
6150                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6151
6152                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6153                                                     num_bytes, empty_size);
6154                 /*
6155                  * If we didn't find a chunk, and we haven't failed on this
6156                  * block group before, and this block group is in the middle of
6157                  * caching and we are ok with waiting, then go ahead and wait
6158                  * for progress to be made, and set failed_alloc to true.
6159                  *
6160                  * If failed_alloc is true then we've already waited on this
6161                  * block group once and should move on to the next block group.
6162                  */
6163                 if (!offset && !failed_alloc && !cached &&
6164                     loop > LOOP_CACHING_NOWAIT) {
6165                         wait_block_group_cache_progress(block_group,
6166                                                 num_bytes + empty_size);
6167                         failed_alloc = true;
6168                         goto have_block_group;
6169                 } else if (!offset) {
6170                         if (!cached)
6171                                 have_caching_bg = true;
6172                         goto loop;
6173                 }
6174 checks:
6175                 search_start = stripe_align(root, used_block_group,
6176                                             offset, num_bytes);
6177
6178                 /* move on to the next group */
6179                 if (search_start + num_bytes >
6180                     used_block_group->key.objectid + used_block_group->key.offset) {
6181                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6182                         goto loop;
6183                 }
6184
6185                 if (offset < search_start)
6186                         btrfs_add_free_space(used_block_group, offset,
6187                                              search_start - offset);
6188                 BUG_ON(offset > search_start);
6189
6190                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
6191                                                   alloc_type);
6192                 if (ret == -EAGAIN) {
6193                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6194                         goto loop;
6195                 }
6196
6197                 /* we are all good, lets return */
6198                 ins->objectid = search_start;
6199                 ins->offset = num_bytes;
6200
6201                 trace_btrfs_reserve_extent(orig_root, block_group,
6202                                            search_start, num_bytes);
6203                 if (used_block_group != block_group)
6204                         btrfs_put_block_group(used_block_group);
6205                 btrfs_put_block_group(block_group);
6206                 break;
6207 loop:
6208                 failed_cluster_refill = false;
6209                 failed_alloc = false;
6210                 BUG_ON(index != get_block_group_index(block_group));
6211                 if (used_block_group != block_group)
6212                         btrfs_put_block_group(used_block_group);
6213                 btrfs_put_block_group(block_group);
6214         }
6215         up_read(&space_info->groups_sem);
6216
6217         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6218                 goto search;
6219
6220         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6221                 goto search;
6222
6223         /*
6224          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6225          *                      caching kthreads as we move along
6226          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6227          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6228          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6229          *                      again
6230          */
6231         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6232                 index = 0;
6233                 loop++;
6234                 if (loop == LOOP_ALLOC_CHUNK) {
6235                         ret = do_chunk_alloc(trans, root, flags,
6236                                              CHUNK_ALLOC_FORCE);
6237                         /*
6238                          * Do not bail out on ENOSPC since we
6239                          * can do more things.
6240                          */
6241                         if (ret < 0 && ret != -ENOSPC) {
6242                                 btrfs_abort_transaction(trans,
6243                                                         root, ret);
6244                                 goto out;
6245                         }
6246                 }
6247
6248                 if (loop == LOOP_NO_EMPTY_SIZE) {
6249                         empty_size = 0;
6250                         empty_cluster = 0;
6251                 }
6252
6253                 goto search;
6254         } else if (!ins->objectid) {
6255                 ret = -ENOSPC;
6256         } else if (ins->objectid) {
6257                 ret = 0;
6258         }
6259 out:
6260
6261         return ret;
6262 }
6263
6264 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6265                             int dump_block_groups)
6266 {
6267         struct btrfs_block_group_cache *cache;
6268         int index = 0;
6269
6270         spin_lock(&info->lock);
6271         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
6272                (unsigned long long)info->flags,
6273                (unsigned long long)(info->total_bytes - info->bytes_used -
6274                                     info->bytes_pinned - info->bytes_reserved -
6275                                     info->bytes_readonly),
6276                (info->full) ? "" : "not ");
6277         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
6278                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6279                (unsigned long long)info->total_bytes,
6280                (unsigned long long)info->bytes_used,
6281                (unsigned long long)info->bytes_pinned,
6282                (unsigned long long)info->bytes_reserved,
6283                (unsigned long long)info->bytes_may_use,
6284                (unsigned long long)info->bytes_readonly);
6285         spin_unlock(&info->lock);
6286
6287         if (!dump_block_groups)
6288                 return;
6289
6290         down_read(&info->groups_sem);
6291 again:
6292         list_for_each_entry(cache, &info->block_groups[index], list) {
6293                 spin_lock(&cache->lock);
6294                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
6295                        (unsigned long long)cache->key.objectid,
6296                        (unsigned long long)cache->key.offset,
6297                        (unsigned long long)btrfs_block_group_used(&cache->item),
6298                        (unsigned long long)cache->pinned,
6299                        (unsigned long long)cache->reserved,
6300                        cache->ro ? "[readonly]" : "");
6301                 btrfs_dump_free_space(cache, bytes);
6302                 spin_unlock(&cache->lock);
6303         }
6304         if (++index < BTRFS_NR_RAID_TYPES)
6305                 goto again;
6306         up_read(&info->groups_sem);
6307 }
6308
6309 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
6310                          struct btrfs_root *root,
6311                          u64 num_bytes, u64 min_alloc_size,
6312                          u64 empty_size, u64 hint_byte,
6313                          struct btrfs_key *ins, int is_data)
6314 {
6315         bool final_tried = false;
6316         u64 flags;
6317         int ret;
6318
6319         flags = btrfs_get_alloc_profile(root, is_data);
6320 again:
6321         WARN_ON(num_bytes < root->sectorsize);
6322         ret = find_free_extent(trans, root, num_bytes, empty_size,
6323                                hint_byte, ins, flags);
6324
6325         if (ret == -ENOSPC) {
6326                 if (!final_tried) {
6327                         num_bytes = num_bytes >> 1;
6328                         num_bytes = round_down(num_bytes, root->sectorsize);
6329                         num_bytes = max(num_bytes, min_alloc_size);
6330                         if (num_bytes == min_alloc_size)
6331                                 final_tried = true;
6332                         goto again;
6333                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6334                         struct btrfs_space_info *sinfo;
6335
6336                         sinfo = __find_space_info(root->fs_info, flags);
6337                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6338                                 (unsigned long long)flags,
6339                                 (unsigned long long)num_bytes);
6340                         if (sinfo)
6341                                 dump_space_info(sinfo, num_bytes, 1);
6342                 }
6343         }
6344
6345         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
6346
6347         return ret;
6348 }
6349
6350 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6351                                         u64 start, u64 len, int pin)
6352 {
6353         struct btrfs_block_group_cache *cache;
6354         int ret = 0;
6355
6356         cache = btrfs_lookup_block_group(root->fs_info, start);
6357         if (!cache) {
6358                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6359                         (unsigned long long)start);
6360                 return -ENOSPC;
6361         }
6362
6363         if (btrfs_test_opt(root, DISCARD))
6364                 ret = btrfs_discard_extent(root, start, len, NULL);
6365
6366         if (pin)
6367                 pin_down_extent(root, cache, start, len, 1);
6368         else {
6369                 btrfs_add_free_space(cache, start, len);
6370                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6371         }
6372         btrfs_put_block_group(cache);
6373
6374         trace_btrfs_reserved_extent_free(root, start, len);
6375
6376         return ret;
6377 }
6378
6379 int btrfs_free_reserved_extent(struct btrfs_root *root,
6380                                         u64 start, u64 len)
6381 {
6382         return __btrfs_free_reserved_extent(root, start, len, 0);
6383 }
6384
6385 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6386                                        u64 start, u64 len)
6387 {
6388         return __btrfs_free_reserved_extent(root, start, len, 1);
6389 }
6390
6391 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6392                                       struct btrfs_root *root,
6393                                       u64 parent, u64 root_objectid,
6394                                       u64 flags, u64 owner, u64 offset,
6395                                       struct btrfs_key *ins, int ref_mod)
6396 {
6397         int ret;
6398         struct btrfs_fs_info *fs_info = root->fs_info;
6399         struct btrfs_extent_item *extent_item;
6400         struct btrfs_extent_inline_ref *iref;
6401         struct btrfs_path *path;
6402         struct extent_buffer *leaf;
6403         int type;
6404         u32 size;
6405
6406         if (parent > 0)
6407                 type = BTRFS_SHARED_DATA_REF_KEY;
6408         else
6409                 type = BTRFS_EXTENT_DATA_REF_KEY;
6410
6411         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6412
6413         path = btrfs_alloc_path();
6414         if (!path)
6415                 return -ENOMEM;
6416
6417         path->leave_spinning = 1;
6418         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6419                                       ins, size);
6420         if (ret) {
6421                 btrfs_free_path(path);
6422                 return ret;
6423         }
6424
6425         leaf = path->nodes[0];
6426         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6427                                      struct btrfs_extent_item);
6428         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6429         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6430         btrfs_set_extent_flags(leaf, extent_item,
6431                                flags | BTRFS_EXTENT_FLAG_DATA);
6432
6433         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6434         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6435         if (parent > 0) {
6436                 struct btrfs_shared_data_ref *ref;
6437                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6438                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6439                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6440         } else {
6441                 struct btrfs_extent_data_ref *ref;
6442                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6443                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6444                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6445                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6446                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6447         }
6448
6449         btrfs_mark_buffer_dirty(path->nodes[0]);
6450         btrfs_free_path(path);
6451
6452         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6453         if (ret) { /* -ENOENT, logic error */
6454                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6455                         (unsigned long long)ins->objectid,
6456                         (unsigned long long)ins->offset);
6457                 BUG();
6458         }
6459         return ret;
6460 }
6461
6462 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6463                                      struct btrfs_root *root,
6464                                      u64 parent, u64 root_objectid,
6465                                      u64 flags, struct btrfs_disk_key *key,
6466                                      int level, struct btrfs_key *ins)
6467 {
6468         int ret;
6469         struct btrfs_fs_info *fs_info = root->fs_info;
6470         struct btrfs_extent_item *extent_item;
6471         struct btrfs_tree_block_info *block_info;
6472         struct btrfs_extent_inline_ref *iref;
6473         struct btrfs_path *path;
6474         struct extent_buffer *leaf;
6475         u32 size = sizeof(*extent_item) + sizeof(*iref);
6476         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6477                                                  SKINNY_METADATA);
6478
6479         if (!skinny_metadata)
6480                 size += sizeof(*block_info);
6481
6482         path = btrfs_alloc_path();
6483         if (!path)
6484                 return -ENOMEM;
6485
6486         path->leave_spinning = 1;
6487         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6488                                       ins, size);
6489         if (ret) {
6490                 btrfs_free_path(path);
6491                 return ret;
6492         }
6493
6494         leaf = path->nodes[0];
6495         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6496                                      struct btrfs_extent_item);
6497         btrfs_set_extent_refs(leaf, extent_item, 1);
6498         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6499         btrfs_set_extent_flags(leaf, extent_item,
6500                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6501
6502         if (skinny_metadata) {
6503                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6504         } else {
6505                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6506                 btrfs_set_tree_block_key(leaf, block_info, key);
6507                 btrfs_set_tree_block_level(leaf, block_info, level);
6508                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6509         }
6510
6511         if (parent > 0) {
6512                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6513                 btrfs_set_extent_inline_ref_type(leaf, iref,
6514                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6515                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6516         } else {
6517                 btrfs_set_extent_inline_ref_type(leaf, iref,
6518                                                  BTRFS_TREE_BLOCK_REF_KEY);
6519                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6520         }
6521
6522         btrfs_mark_buffer_dirty(leaf);
6523         btrfs_free_path(path);
6524
6525         ret = update_block_group(root, ins->objectid, root->leafsize, 1);
6526         if (ret) { /* -ENOENT, logic error */
6527                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6528                         (unsigned long long)ins->objectid,
6529                         (unsigned long long)ins->offset);
6530                 BUG();
6531         }
6532         return ret;
6533 }
6534
6535 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6536                                      struct btrfs_root *root,
6537                                      u64 root_objectid, u64 owner,
6538                                      u64 offset, struct btrfs_key *ins)
6539 {
6540         int ret;
6541
6542         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6543
6544         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6545                                          ins->offset, 0,
6546                                          root_objectid, owner, offset,
6547                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6548         return ret;
6549 }
6550
6551 /*
6552  * this is used by the tree logging recovery code.  It records that
6553  * an extent has been allocated and makes sure to clear the free
6554  * space cache bits as well
6555  */
6556 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6557                                    struct btrfs_root *root,
6558                                    u64 root_objectid, u64 owner, u64 offset,
6559                                    struct btrfs_key *ins)
6560 {
6561         int ret;
6562         struct btrfs_block_group_cache *block_group;
6563         struct btrfs_caching_control *caching_ctl;
6564         u64 start = ins->objectid;
6565         u64 num_bytes = ins->offset;
6566
6567         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6568         cache_block_group(block_group, 0);
6569         caching_ctl = get_caching_control(block_group);
6570
6571         if (!caching_ctl) {
6572                 BUG_ON(!block_group_cache_done(block_group));
6573                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6574                 if (ret)
6575                         goto out;
6576         } else {
6577                 mutex_lock(&caching_ctl->mutex);
6578
6579                 if (start >= caching_ctl->progress) {
6580                         ret = add_excluded_extent(root, start, num_bytes);
6581                 } else if (start + num_bytes <= caching_ctl->progress) {
6582                         ret = btrfs_remove_free_space(block_group,
6583                                                       start, num_bytes);
6584                 } else {
6585                         num_bytes = caching_ctl->progress - start;
6586                         ret = btrfs_remove_free_space(block_group,
6587                                                       start, num_bytes);
6588                         if (ret)
6589                                 goto out_lock;
6590
6591                         start = caching_ctl->progress;
6592                         num_bytes = ins->objectid + ins->offset -
6593                                     caching_ctl->progress;
6594                         ret = add_excluded_extent(root, start, num_bytes);
6595                 }
6596 out_lock:
6597                 mutex_unlock(&caching_ctl->mutex);
6598                 put_caching_control(caching_ctl);
6599                 if (ret)
6600                         goto out;
6601         }
6602
6603         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6604                                           RESERVE_ALLOC_NO_ACCOUNT);
6605         BUG_ON(ret); /* logic error */
6606         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6607                                          0, owner, offset, ins, 1);
6608 out:
6609         btrfs_put_block_group(block_group);
6610         return ret;
6611 }
6612
6613 static struct extent_buffer *
6614 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6615                       u64 bytenr, u32 blocksize, int level)
6616 {
6617         struct extent_buffer *buf;
6618
6619         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6620         if (!buf)
6621                 return ERR_PTR(-ENOMEM);
6622         btrfs_set_header_generation(buf, trans->transid);
6623         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6624         btrfs_tree_lock(buf);
6625         clean_tree_block(trans, root, buf);
6626         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6627
6628         btrfs_set_lock_blocking(buf);
6629         btrfs_set_buffer_uptodate(buf);
6630
6631         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6632                 /*
6633                  * we allow two log transactions at a time, use different
6634                  * EXENT bit to differentiate dirty pages.
6635                  */
6636                 if (root->log_transid % 2 == 0)
6637                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6638                                         buf->start + buf->len - 1, GFP_NOFS);
6639                 else
6640                         set_extent_new(&root->dirty_log_pages, buf->start,
6641                                         buf->start + buf->len - 1, GFP_NOFS);
6642         } else {
6643                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6644                          buf->start + buf->len - 1, GFP_NOFS);
6645         }
6646         trans->blocks_used++;
6647         /* this returns a buffer locked for blocking */
6648         return buf;
6649 }
6650
6651 static struct btrfs_block_rsv *
6652 use_block_rsv(struct btrfs_trans_handle *trans,
6653               struct btrfs_root *root, u32 blocksize)
6654 {
6655         struct btrfs_block_rsv *block_rsv;
6656         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6657         int ret;
6658         bool global_updated = false;
6659
6660         block_rsv = get_block_rsv(trans, root);
6661
6662         if (unlikely(block_rsv->size == 0))
6663                 goto try_reserve;
6664 again:
6665         ret = block_rsv_use_bytes(block_rsv, blocksize);
6666         if (!ret)
6667                 return block_rsv;
6668
6669         if (block_rsv->failfast)
6670                 return ERR_PTR(ret);
6671
6672         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
6673                 global_updated = true;
6674                 update_global_block_rsv(root->fs_info);
6675                 goto again;
6676         }
6677
6678         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6679                 static DEFINE_RATELIMIT_STATE(_rs,
6680                                 DEFAULT_RATELIMIT_INTERVAL * 10,
6681                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
6682                 if (__ratelimit(&_rs))
6683                         WARN(1, KERN_DEBUG
6684                                 "btrfs: block rsv returned %d\n", ret);
6685         }
6686 try_reserve:
6687         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
6688                                      BTRFS_RESERVE_NO_FLUSH);
6689         if (!ret)
6690                 return block_rsv;
6691         /*
6692          * If we couldn't reserve metadata bytes try and use some from
6693          * the global reserve if its space type is the same as the global
6694          * reservation.
6695          */
6696         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
6697             block_rsv->space_info == global_rsv->space_info) {
6698                 ret = block_rsv_use_bytes(global_rsv, blocksize);
6699                 if (!ret)
6700                         return global_rsv;
6701         }
6702         return ERR_PTR(ret);
6703 }
6704
6705 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6706                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6707 {
6708         block_rsv_add_bytes(block_rsv, blocksize, 0);
6709         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6710 }
6711
6712 /*
6713  * finds a free extent and does all the dirty work required for allocation
6714  * returns the key for the extent through ins, and a tree buffer for
6715  * the first block of the extent through buf.
6716  *
6717  * returns the tree buffer or NULL.
6718  */
6719 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6720                                         struct btrfs_root *root, u32 blocksize,
6721                                         u64 parent, u64 root_objectid,
6722                                         struct btrfs_disk_key *key, int level,
6723                                         u64 hint, u64 empty_size)
6724 {
6725         struct btrfs_key ins;
6726         struct btrfs_block_rsv *block_rsv;
6727         struct extent_buffer *buf;
6728         u64 flags = 0;
6729         int ret;
6730         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6731                                                  SKINNY_METADATA);
6732
6733         block_rsv = use_block_rsv(trans, root, blocksize);
6734         if (IS_ERR(block_rsv))
6735                 return ERR_CAST(block_rsv);
6736
6737         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6738                                    empty_size, hint, &ins, 0);
6739         if (ret) {
6740                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6741                 return ERR_PTR(ret);
6742         }
6743
6744         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6745                                     blocksize, level);
6746         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
6747
6748         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6749                 if (parent == 0)
6750                         parent = ins.objectid;
6751                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6752         } else
6753                 BUG_ON(parent > 0);
6754
6755         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6756                 struct btrfs_delayed_extent_op *extent_op;
6757                 extent_op = btrfs_alloc_delayed_extent_op();
6758                 BUG_ON(!extent_op); /* -ENOMEM */
6759                 if (key)
6760                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6761                 else
6762                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6763                 extent_op->flags_to_set = flags;
6764                 if (skinny_metadata)
6765                         extent_op->update_key = 0;
6766                 else
6767                         extent_op->update_key = 1;
6768                 extent_op->update_flags = 1;
6769                 extent_op->is_data = 0;
6770                 extent_op->level = level;
6771
6772                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6773                                         ins.objectid,
6774                                         ins.offset, parent, root_objectid,
6775                                         level, BTRFS_ADD_DELAYED_EXTENT,
6776                                         extent_op, 0);
6777                 BUG_ON(ret); /* -ENOMEM */
6778         }
6779         return buf;
6780 }
6781
6782 struct walk_control {
6783         u64 refs[BTRFS_MAX_LEVEL];
6784         u64 flags[BTRFS_MAX_LEVEL];
6785         struct btrfs_key update_progress;
6786         int stage;
6787         int level;
6788         int shared_level;
6789         int update_ref;
6790         int keep_locks;
6791         int reada_slot;
6792         int reada_count;
6793         int for_reloc;
6794 };
6795
6796 #define DROP_REFERENCE  1
6797 #define UPDATE_BACKREF  2
6798
6799 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6800                                      struct btrfs_root *root,
6801                                      struct walk_control *wc,
6802                                      struct btrfs_path *path)
6803 {
6804         u64 bytenr;
6805         u64 generation;
6806         u64 refs;
6807         u64 flags;
6808         u32 nritems;
6809         u32 blocksize;
6810         struct btrfs_key key;
6811         struct extent_buffer *eb;
6812         int ret;
6813         int slot;
6814         int nread = 0;
6815
6816         if (path->slots[wc->level] < wc->reada_slot) {
6817                 wc->reada_count = wc->reada_count * 2 / 3;
6818                 wc->reada_count = max(wc->reada_count, 2);
6819         } else {
6820                 wc->reada_count = wc->reada_count * 3 / 2;
6821                 wc->reada_count = min_t(int, wc->reada_count,
6822                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6823         }
6824
6825         eb = path->nodes[wc->level];
6826         nritems = btrfs_header_nritems(eb);
6827         blocksize = btrfs_level_size(root, wc->level - 1);
6828
6829         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6830                 if (nread >= wc->reada_count)
6831                         break;
6832
6833                 cond_resched();
6834                 bytenr = btrfs_node_blockptr(eb, slot);
6835                 generation = btrfs_node_ptr_generation(eb, slot);
6836
6837                 if (slot == path->slots[wc->level])
6838                         goto reada;
6839
6840                 if (wc->stage == UPDATE_BACKREF &&
6841                     generation <= root->root_key.offset)
6842                         continue;
6843
6844                 /* We don't lock the tree block, it's OK to be racy here */
6845                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
6846                                                wc->level - 1, 1, &refs,
6847                                                &flags);
6848                 /* We don't care about errors in readahead. */
6849                 if (ret < 0)
6850                         continue;
6851                 BUG_ON(refs == 0);
6852
6853                 if (wc->stage == DROP_REFERENCE) {
6854                         if (refs == 1)
6855                                 goto reada;
6856
6857                         if (wc->level == 1 &&
6858                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6859                                 continue;
6860                         if (!wc->update_ref ||
6861                             generation <= root->root_key.offset)
6862                                 continue;
6863                         btrfs_node_key_to_cpu(eb, &key, slot);
6864                         ret = btrfs_comp_cpu_keys(&key,
6865                                                   &wc->update_progress);
6866                         if (ret < 0)
6867                                 continue;
6868                 } else {
6869                         if (wc->level == 1 &&
6870                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6871                                 continue;
6872                 }
6873 reada:
6874                 ret = readahead_tree_block(root, bytenr, blocksize,
6875                                            generation);
6876                 if (ret)
6877                         break;
6878                 nread++;
6879         }
6880         wc->reada_slot = slot;
6881 }
6882
6883 /*
6884  * helper to process tree block while walking down the tree.
6885  *
6886  * when wc->stage == UPDATE_BACKREF, this function updates
6887  * back refs for pointers in the block.
6888  *
6889  * NOTE: return value 1 means we should stop walking down.
6890  */
6891 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6892                                    struct btrfs_root *root,
6893                                    struct btrfs_path *path,
6894                                    struct walk_control *wc, int lookup_info)
6895 {
6896         int level = wc->level;
6897         struct extent_buffer *eb = path->nodes[level];
6898         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6899         int ret;
6900
6901         if (wc->stage == UPDATE_BACKREF &&
6902             btrfs_header_owner(eb) != root->root_key.objectid)
6903                 return 1;
6904
6905         /*
6906          * when reference count of tree block is 1, it won't increase
6907          * again. once full backref flag is set, we never clear it.
6908          */
6909         if (lookup_info &&
6910             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6911              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6912                 BUG_ON(!path->locks[level]);
6913                 ret = btrfs_lookup_extent_info(trans, root,
6914                                                eb->start, level, 1,
6915                                                &wc->refs[level],
6916                                                &wc->flags[level]);
6917                 BUG_ON(ret == -ENOMEM);
6918                 if (ret)
6919                         return ret;
6920                 BUG_ON(wc->refs[level] == 0);
6921         }
6922
6923         if (wc->stage == DROP_REFERENCE) {
6924                 if (wc->refs[level] > 1)
6925                         return 1;
6926
6927                 if (path->locks[level] && !wc->keep_locks) {
6928                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6929                         path->locks[level] = 0;
6930                 }
6931                 return 0;
6932         }
6933
6934         /* wc->stage == UPDATE_BACKREF */
6935         if (!(wc->flags[level] & flag)) {
6936                 BUG_ON(!path->locks[level]);
6937                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
6938                 BUG_ON(ret); /* -ENOMEM */
6939                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
6940                 BUG_ON(ret); /* -ENOMEM */
6941                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6942                                                   eb->len, flag,
6943                                                   btrfs_header_level(eb), 0);
6944                 BUG_ON(ret); /* -ENOMEM */
6945                 wc->flags[level] |= flag;
6946         }
6947
6948         /*
6949          * the block is shared by multiple trees, so it's not good to
6950          * keep the tree lock
6951          */
6952         if (path->locks[level] && level > 0) {
6953                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6954                 path->locks[level] = 0;
6955         }
6956         return 0;
6957 }
6958
6959 /*
6960  * helper to process tree block pointer.
6961  *
6962  * when wc->stage == DROP_REFERENCE, this function checks
6963  * reference count of the block pointed to. if the block
6964  * is shared and we need update back refs for the subtree
6965  * rooted at the block, this function changes wc->stage to
6966  * UPDATE_BACKREF. if the block is shared and there is no
6967  * need to update back, this function drops the reference
6968  * to the block.
6969  *
6970  * NOTE: return value 1 means we should stop walking down.
6971  */
6972 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6973                                  struct btrfs_root *root,
6974                                  struct btrfs_path *path,
6975                                  struct walk_control *wc, int *lookup_info)
6976 {
6977         u64 bytenr;
6978         u64 generation;
6979         u64 parent;
6980         u32 blocksize;
6981         struct btrfs_key key;
6982         struct extent_buffer *next;
6983         int level = wc->level;
6984         int reada = 0;
6985         int ret = 0;
6986
6987         generation = btrfs_node_ptr_generation(path->nodes[level],
6988                                                path->slots[level]);
6989         /*
6990          * if the lower level block was created before the snapshot
6991          * was created, we know there is no need to update back refs
6992          * for the subtree
6993          */
6994         if (wc->stage == UPDATE_BACKREF &&
6995             generation <= root->root_key.offset) {
6996                 *lookup_info = 1;
6997                 return 1;
6998         }
6999
7000         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7001         blocksize = btrfs_level_size(root, level - 1);
7002
7003         next = btrfs_find_tree_block(root, bytenr, blocksize);
7004         if (!next) {
7005                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
7006                 if (!next)
7007                         return -ENOMEM;
7008                 reada = 1;
7009         }
7010         btrfs_tree_lock(next);
7011         btrfs_set_lock_blocking(next);
7012
7013         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7014                                        &wc->refs[level - 1],
7015                                        &wc->flags[level - 1]);
7016         if (ret < 0) {
7017                 btrfs_tree_unlock(next);
7018                 return ret;
7019         }
7020
7021         if (unlikely(wc->refs[level - 1] == 0)) {
7022                 btrfs_err(root->fs_info, "Missing references.");
7023                 BUG();
7024         }
7025         *lookup_info = 0;
7026
7027         if (wc->stage == DROP_REFERENCE) {
7028                 if (wc->refs[level - 1] > 1) {
7029                         if (level == 1 &&
7030                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7031                                 goto skip;
7032
7033                         if (!wc->update_ref ||
7034                             generation <= root->root_key.offset)
7035                                 goto skip;
7036
7037                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7038                                               path->slots[level]);
7039                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7040                         if (ret < 0)
7041                                 goto skip;
7042
7043                         wc->stage = UPDATE_BACKREF;
7044                         wc->shared_level = level - 1;
7045                 }
7046         } else {
7047                 if (level == 1 &&
7048                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7049                         goto skip;
7050         }
7051
7052         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7053                 btrfs_tree_unlock(next);
7054                 free_extent_buffer(next);
7055                 next = NULL;
7056                 *lookup_info = 1;
7057         }
7058
7059         if (!next) {
7060                 if (reada && level == 1)
7061                         reada_walk_down(trans, root, wc, path);
7062                 next = read_tree_block(root, bytenr, blocksize, generation);
7063                 if (!next || !extent_buffer_uptodate(next)) {
7064                         free_extent_buffer(next);
7065                         return -EIO;
7066                 }
7067                 btrfs_tree_lock(next);
7068                 btrfs_set_lock_blocking(next);
7069         }
7070
7071         level--;
7072         BUG_ON(level != btrfs_header_level(next));
7073         path->nodes[level] = next;
7074         path->slots[level] = 0;
7075         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7076         wc->level = level;
7077         if (wc->level == 1)
7078                 wc->reada_slot = 0;
7079         return 0;
7080 skip:
7081         wc->refs[level - 1] = 0;
7082         wc->flags[level - 1] = 0;
7083         if (wc->stage == DROP_REFERENCE) {
7084                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7085                         parent = path->nodes[level]->start;
7086                 } else {
7087                         BUG_ON(root->root_key.objectid !=
7088                                btrfs_header_owner(path->nodes[level]));
7089                         parent = 0;
7090                 }
7091
7092                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7093                                 root->root_key.objectid, level - 1, 0, 0);
7094                 BUG_ON(ret); /* -ENOMEM */
7095         }
7096         btrfs_tree_unlock(next);
7097         free_extent_buffer(next);
7098         *lookup_info = 1;
7099         return 1;
7100 }
7101
7102 /*
7103  * helper to process tree block while walking up the tree.
7104  *
7105  * when wc->stage == DROP_REFERENCE, this function drops
7106  * reference count on the block.
7107  *
7108  * when wc->stage == UPDATE_BACKREF, this function changes
7109  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7110  * to UPDATE_BACKREF previously while processing the block.
7111  *
7112  * NOTE: return value 1 means we should stop walking up.
7113  */
7114 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7115                                  struct btrfs_root *root,
7116                                  struct btrfs_path *path,
7117                                  struct walk_control *wc)
7118 {
7119         int ret;
7120         int level = wc->level;
7121         struct extent_buffer *eb = path->nodes[level];
7122         u64 parent = 0;
7123
7124         if (wc->stage == UPDATE_BACKREF) {
7125                 BUG_ON(wc->shared_level < level);
7126                 if (level < wc->shared_level)
7127                         goto out;
7128
7129                 ret = find_next_key(path, level + 1, &wc->update_progress);
7130                 if (ret > 0)
7131                         wc->update_ref = 0;
7132
7133                 wc->stage = DROP_REFERENCE;
7134                 wc->shared_level = -1;
7135                 path->slots[level] = 0;
7136
7137                 /*
7138                  * check reference count again if the block isn't locked.
7139                  * we should start walking down the tree again if reference
7140                  * count is one.
7141                  */
7142                 if (!path->locks[level]) {
7143                         BUG_ON(level == 0);
7144                         btrfs_tree_lock(eb);
7145                         btrfs_set_lock_blocking(eb);
7146                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7147
7148                         ret = btrfs_lookup_extent_info(trans, root,
7149                                                        eb->start, level, 1,
7150                                                        &wc->refs[level],
7151                                                        &wc->flags[level]);
7152                         if (ret < 0) {
7153                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7154                                 path->locks[level] = 0;
7155                                 return ret;
7156                         }
7157                         BUG_ON(wc->refs[level] == 0);
7158                         if (wc->refs[level] == 1) {
7159                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7160                                 path->locks[level] = 0;
7161                                 return 1;
7162                         }
7163                 }
7164         }
7165
7166         /* wc->stage == DROP_REFERENCE */
7167         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7168
7169         if (wc->refs[level] == 1) {
7170                 if (level == 0) {
7171                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7172                                 ret = btrfs_dec_ref(trans, root, eb, 1,
7173                                                     wc->for_reloc);
7174                         else
7175                                 ret = btrfs_dec_ref(trans, root, eb, 0,
7176                                                     wc->for_reloc);
7177                         BUG_ON(ret); /* -ENOMEM */
7178                 }
7179                 /* make block locked assertion in clean_tree_block happy */
7180                 if (!path->locks[level] &&
7181                     btrfs_header_generation(eb) == trans->transid) {
7182                         btrfs_tree_lock(eb);
7183                         btrfs_set_lock_blocking(eb);
7184                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7185                 }
7186                 clean_tree_block(trans, root, eb);
7187         }
7188
7189         if (eb == root->node) {
7190                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7191                         parent = eb->start;
7192                 else
7193                         BUG_ON(root->root_key.objectid !=
7194                                btrfs_header_owner(eb));
7195         } else {
7196                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7197                         parent = path->nodes[level + 1]->start;
7198                 else
7199                         BUG_ON(root->root_key.objectid !=
7200                                btrfs_header_owner(path->nodes[level + 1]));
7201         }
7202
7203         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7204 out:
7205         wc->refs[level] = 0;
7206         wc->flags[level] = 0;
7207         return 0;
7208 }
7209
7210 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7211                                    struct btrfs_root *root,
7212                                    struct btrfs_path *path,
7213                                    struct walk_control *wc)
7214 {
7215         int level = wc->level;
7216         int lookup_info = 1;
7217         int ret;
7218
7219         while (level >= 0) {
7220                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
7221                 if (ret > 0)
7222                         break;
7223
7224                 if (level == 0)
7225                         break;
7226
7227                 if (path->slots[level] >=
7228                     btrfs_header_nritems(path->nodes[level]))
7229                         break;
7230
7231                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
7232                 if (ret > 0) {
7233                         path->slots[level]++;
7234                         continue;
7235                 } else if (ret < 0)
7236                         return ret;
7237                 level = wc->level;
7238         }
7239         return 0;
7240 }
7241
7242 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
7243                                  struct btrfs_root *root,
7244                                  struct btrfs_path *path,
7245                                  struct walk_control *wc, int max_level)
7246 {
7247         int level = wc->level;
7248         int ret;
7249
7250         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
7251         while (level < max_level && path->nodes[level]) {
7252                 wc->level = level;
7253                 if (path->slots[level] + 1 <
7254                     btrfs_header_nritems(path->nodes[level])) {
7255                         path->slots[level]++;
7256                         return 0;
7257                 } else {
7258                         ret = walk_up_proc(trans, root, path, wc);
7259                         if (ret > 0)
7260                                 return 0;
7261
7262                         if (path->locks[level]) {
7263                                 btrfs_tree_unlock_rw(path->nodes[level],
7264                                                      path->locks[level]);
7265                                 path->locks[level] = 0;
7266                         }
7267                         free_extent_buffer(path->nodes[level]);
7268                         path->nodes[level] = NULL;
7269                         level++;
7270                 }
7271         }
7272         return 1;
7273 }
7274
7275 /*
7276  * drop a subvolume tree.
7277  *
7278  * this function traverses the tree freeing any blocks that only
7279  * referenced by the tree.
7280  *
7281  * when a shared tree block is found. this function decreases its
7282  * reference count by one. if update_ref is true, this function
7283  * also make sure backrefs for the shared block and all lower level
7284  * blocks are properly updated.
7285  *
7286  * If called with for_reloc == 0, may exit early with -EAGAIN
7287  */
7288 int btrfs_drop_snapshot(struct btrfs_root *root,
7289                          struct btrfs_block_rsv *block_rsv, int update_ref,
7290                          int for_reloc)
7291 {
7292         struct btrfs_path *path;
7293         struct btrfs_trans_handle *trans;
7294         struct btrfs_root *tree_root = root->fs_info->tree_root;
7295         struct btrfs_root_item *root_item = &root->root_item;
7296         struct walk_control *wc;
7297         struct btrfs_key key;
7298         int err = 0;
7299         int ret;
7300         int level;
7301
7302         path = btrfs_alloc_path();
7303         if (!path) {
7304                 err = -ENOMEM;
7305                 goto out;
7306         }
7307
7308         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7309         if (!wc) {
7310                 btrfs_free_path(path);
7311                 err = -ENOMEM;
7312                 goto out;
7313         }
7314
7315         trans = btrfs_start_transaction(tree_root, 0);
7316         if (IS_ERR(trans)) {
7317                 err = PTR_ERR(trans);
7318                 goto out_free;
7319         }
7320
7321         if (block_rsv)
7322                 trans->block_rsv = block_rsv;
7323
7324         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
7325                 level = btrfs_header_level(root->node);
7326                 path->nodes[level] = btrfs_lock_root_node(root);
7327                 btrfs_set_lock_blocking(path->nodes[level]);
7328                 path->slots[level] = 0;
7329                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7330                 memset(&wc->update_progress, 0,
7331                        sizeof(wc->update_progress));
7332         } else {
7333                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
7334                 memcpy(&wc->update_progress, &key,
7335                        sizeof(wc->update_progress));
7336
7337                 level = root_item->drop_level;
7338                 BUG_ON(level == 0);
7339                 path->lowest_level = level;
7340                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
7341                 path->lowest_level = 0;
7342                 if (ret < 0) {
7343                         err = ret;
7344                         goto out_end_trans;
7345                 }
7346                 WARN_ON(ret > 0);
7347
7348                 /*
7349                  * unlock our path, this is safe because only this
7350                  * function is allowed to delete this snapshot
7351                  */
7352                 btrfs_unlock_up_safe(path, 0);
7353
7354                 level = btrfs_header_level(root->node);
7355                 while (1) {
7356                         btrfs_tree_lock(path->nodes[level]);
7357                         btrfs_set_lock_blocking(path->nodes[level]);
7358
7359                         ret = btrfs_lookup_extent_info(trans, root,
7360                                                 path->nodes[level]->start,
7361                                                 level, 1, &wc->refs[level],
7362                                                 &wc->flags[level]);
7363                         if (ret < 0) {
7364                                 err = ret;
7365                                 goto out_end_trans;
7366                         }
7367                         BUG_ON(wc->refs[level] == 0);
7368
7369                         if (level == root_item->drop_level)
7370                                 break;
7371
7372                         btrfs_tree_unlock(path->nodes[level]);
7373                         WARN_ON(wc->refs[level] != 1);
7374                         level--;
7375                 }
7376         }
7377
7378         wc->level = level;
7379         wc->shared_level = -1;
7380         wc->stage = DROP_REFERENCE;
7381         wc->update_ref = update_ref;
7382         wc->keep_locks = 0;
7383         wc->for_reloc = for_reloc;
7384         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7385
7386         while (1) {
7387                 if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
7388                         pr_debug("btrfs: drop snapshot early exit\n");
7389                         err = -EAGAIN;
7390                         goto out_end_trans;
7391                 }
7392
7393                 ret = walk_down_tree(trans, root, path, wc);
7394                 if (ret < 0) {
7395                         err = ret;
7396                         break;
7397                 }
7398
7399                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7400                 if (ret < 0) {
7401                         err = ret;
7402                         break;
7403                 }
7404
7405                 if (ret > 0) {
7406                         BUG_ON(wc->stage != DROP_REFERENCE);
7407                         break;
7408                 }
7409
7410                 if (wc->stage == DROP_REFERENCE) {
7411                         level = wc->level;
7412                         btrfs_node_key(path->nodes[level],
7413                                        &root_item->drop_progress,
7414                                        path->slots[level]);
7415                         root_item->drop_level = level;
7416                 }
7417
7418                 BUG_ON(wc->level == 0);
7419                 if (btrfs_should_end_transaction(trans, tree_root)) {
7420                         ret = btrfs_update_root(trans, tree_root,
7421                                                 &root->root_key,
7422                                                 root_item);
7423                         if (ret) {
7424                                 btrfs_abort_transaction(trans, tree_root, ret);
7425                                 err = ret;
7426                                 goto out_end_trans;
7427                         }
7428
7429                         btrfs_end_transaction_throttle(trans, tree_root);
7430                         trans = btrfs_start_transaction(tree_root, 0);
7431                         if (IS_ERR(trans)) {
7432                                 err = PTR_ERR(trans);
7433                                 goto out_free;
7434                         }
7435                         if (block_rsv)
7436                                 trans->block_rsv = block_rsv;
7437                 }
7438         }
7439         btrfs_release_path(path);
7440         if (err)
7441                 goto out_end_trans;
7442
7443         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7444         if (ret) {
7445                 btrfs_abort_transaction(trans, tree_root, ret);
7446                 goto out_end_trans;
7447         }
7448
7449         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7450                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
7451                                            NULL, NULL);
7452                 if (ret < 0) {
7453                         btrfs_abort_transaction(trans, tree_root, ret);
7454                         err = ret;
7455                         goto out_end_trans;
7456                 } else if (ret > 0) {
7457                         /* if we fail to delete the orphan item this time
7458                          * around, it'll get picked up the next time.
7459                          *
7460                          * The most common failure here is just -ENOENT.
7461                          */
7462                         btrfs_del_orphan_item(trans, tree_root,
7463                                               root->root_key.objectid);
7464                 }
7465         }
7466
7467         if (root->in_radix) {
7468                 btrfs_free_fs_root(tree_root->fs_info, root);
7469         } else {
7470                 free_extent_buffer(root->node);
7471                 free_extent_buffer(root->commit_root);
7472                 kfree(root);
7473         }
7474 out_end_trans:
7475         btrfs_end_transaction_throttle(trans, tree_root);
7476 out_free:
7477         kfree(wc);
7478         btrfs_free_path(path);
7479 out:
7480         if (err)
7481                 btrfs_std_error(root->fs_info, err);
7482         return err;
7483 }
7484
7485 /*
7486  * drop subtree rooted at tree block 'node'.
7487  *
7488  * NOTE: this function will unlock and release tree block 'node'
7489  * only used by relocation code
7490  */
7491 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7492                         struct btrfs_root *root,
7493                         struct extent_buffer *node,
7494                         struct extent_buffer *parent)
7495 {
7496         struct btrfs_path *path;
7497         struct walk_control *wc;
7498         int level;
7499         int parent_level;
7500         int ret = 0;
7501         int wret;
7502
7503         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7504
7505         path = btrfs_alloc_path();
7506         if (!path)
7507                 return -ENOMEM;
7508
7509         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7510         if (!wc) {
7511                 btrfs_free_path(path);
7512                 return -ENOMEM;
7513         }
7514
7515         btrfs_assert_tree_locked(parent);
7516         parent_level = btrfs_header_level(parent);
7517         extent_buffer_get(parent);
7518         path->nodes[parent_level] = parent;
7519         path->slots[parent_level] = btrfs_header_nritems(parent);
7520
7521         btrfs_assert_tree_locked(node);
7522         level = btrfs_header_level(node);
7523         path->nodes[level] = node;
7524         path->slots[level] = 0;
7525         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7526
7527         wc->refs[parent_level] = 1;
7528         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7529         wc->level = level;
7530         wc->shared_level = -1;
7531         wc->stage = DROP_REFERENCE;
7532         wc->update_ref = 0;
7533         wc->keep_locks = 1;
7534         wc->for_reloc = 1;
7535         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7536
7537         while (1) {
7538                 wret = walk_down_tree(trans, root, path, wc);
7539                 if (wret < 0) {
7540                         ret = wret;
7541                         break;
7542                 }
7543
7544                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7545                 if (wret < 0)
7546                         ret = wret;
7547                 if (wret != 0)
7548                         break;
7549         }
7550
7551         kfree(wc);
7552         btrfs_free_path(path);
7553         return ret;
7554 }
7555
7556 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7557 {
7558         u64 num_devices;
7559         u64 stripped;
7560
7561         /*
7562          * if restripe for this chunk_type is on pick target profile and
7563          * return, otherwise do the usual balance
7564          */
7565         stripped = get_restripe_target(root->fs_info, flags);
7566         if (stripped)
7567                 return extended_to_chunk(stripped);
7568
7569         /*
7570          * we add in the count of missing devices because we want
7571          * to make sure that any RAID levels on a degraded FS
7572          * continue to be honored.
7573          */
7574         num_devices = root->fs_info->fs_devices->rw_devices +
7575                 root->fs_info->fs_devices->missing_devices;
7576
7577         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7578                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
7579                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7580
7581         if (num_devices == 1) {
7582                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7583                 stripped = flags & ~stripped;
7584
7585                 /* turn raid0 into single device chunks */
7586                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7587                         return stripped;
7588
7589                 /* turn mirroring into duplication */
7590                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7591                              BTRFS_BLOCK_GROUP_RAID10))
7592                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7593         } else {
7594                 /* they already had raid on here, just return */
7595                 if (flags & stripped)
7596                         return flags;
7597
7598                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7599                 stripped = flags & ~stripped;
7600
7601                 /* switch duplicated blocks with raid1 */
7602                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7603                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7604
7605                 /* this is drive concat, leave it alone */
7606         }
7607
7608         return flags;
7609 }
7610
7611 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7612 {
7613         struct btrfs_space_info *sinfo = cache->space_info;
7614         u64 num_bytes;
7615         u64 min_allocable_bytes;
7616         int ret = -ENOSPC;
7617
7618
7619         /*
7620          * We need some metadata space and system metadata space for
7621          * allocating chunks in some corner cases until we force to set
7622          * it to be readonly.
7623          */
7624         if ((sinfo->flags &
7625              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7626             !force)
7627                 min_allocable_bytes = 1 * 1024 * 1024;
7628         else
7629                 min_allocable_bytes = 0;
7630
7631         spin_lock(&sinfo->lock);
7632         spin_lock(&cache->lock);
7633
7634         if (cache->ro) {
7635                 ret = 0;
7636                 goto out;
7637         }
7638
7639         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7640                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7641
7642         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7643             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7644             min_allocable_bytes <= sinfo->total_bytes) {
7645                 sinfo->bytes_readonly += num_bytes;
7646                 cache->ro = 1;
7647                 ret = 0;
7648         }
7649 out:
7650         spin_unlock(&cache->lock);
7651         spin_unlock(&sinfo->lock);
7652         return ret;
7653 }
7654
7655 int btrfs_set_block_group_ro(struct btrfs_root *root,
7656                              struct btrfs_block_group_cache *cache)
7657
7658 {
7659         struct btrfs_trans_handle *trans;
7660         u64 alloc_flags;
7661         int ret;
7662
7663         BUG_ON(cache->ro);
7664
7665         trans = btrfs_join_transaction(root);
7666         if (IS_ERR(trans))
7667                 return PTR_ERR(trans);
7668
7669         alloc_flags = update_block_group_flags(root, cache->flags);
7670         if (alloc_flags != cache->flags) {
7671                 ret = do_chunk_alloc(trans, root, alloc_flags,
7672                                      CHUNK_ALLOC_FORCE);
7673                 if (ret < 0)
7674                         goto out;
7675         }
7676
7677         ret = set_block_group_ro(cache, 0);
7678         if (!ret)
7679                 goto out;
7680         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7681         ret = do_chunk_alloc(trans, root, alloc_flags,
7682                              CHUNK_ALLOC_FORCE);
7683         if (ret < 0)
7684                 goto out;
7685         ret = set_block_group_ro(cache, 0);
7686 out:
7687         btrfs_end_transaction(trans, root);
7688         return ret;
7689 }
7690
7691 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7692                             struct btrfs_root *root, u64 type)
7693 {
7694         u64 alloc_flags = get_alloc_profile(root, type);
7695         return do_chunk_alloc(trans, root, alloc_flags,
7696                               CHUNK_ALLOC_FORCE);
7697 }
7698
7699 /*
7700  * helper to account the unused space of all the readonly block group in the
7701  * list. takes mirrors into account.
7702  */
7703 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7704 {
7705         struct btrfs_block_group_cache *block_group;
7706         u64 free_bytes = 0;
7707         int factor;
7708
7709         list_for_each_entry(block_group, groups_list, list) {
7710                 spin_lock(&block_group->lock);
7711
7712                 if (!block_group->ro) {
7713                         spin_unlock(&block_group->lock);
7714                         continue;
7715                 }
7716
7717                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7718                                           BTRFS_BLOCK_GROUP_RAID10 |
7719                                           BTRFS_BLOCK_GROUP_DUP))
7720                         factor = 2;
7721                 else
7722                         factor = 1;
7723
7724                 free_bytes += (block_group->key.offset -
7725                                btrfs_block_group_used(&block_group->item)) *
7726                                factor;
7727
7728                 spin_unlock(&block_group->lock);
7729         }
7730
7731         return free_bytes;
7732 }
7733
7734 /*
7735  * helper to account the unused space of all the readonly block group in the
7736  * space_info. takes mirrors into account.
7737  */
7738 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7739 {
7740         int i;
7741         u64 free_bytes = 0;
7742
7743         spin_lock(&sinfo->lock);
7744
7745         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7746                 if (!list_empty(&sinfo->block_groups[i]))
7747                         free_bytes += __btrfs_get_ro_block_group_free_space(
7748                                                 &sinfo->block_groups[i]);
7749
7750         spin_unlock(&sinfo->lock);
7751
7752         return free_bytes;
7753 }
7754
7755 void btrfs_set_block_group_rw(struct btrfs_root *root,
7756                               struct btrfs_block_group_cache *cache)
7757 {
7758         struct btrfs_space_info *sinfo = cache->space_info;
7759         u64 num_bytes;
7760
7761         BUG_ON(!cache->ro);
7762
7763         spin_lock(&sinfo->lock);
7764         spin_lock(&cache->lock);
7765         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7766                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7767         sinfo->bytes_readonly -= num_bytes;
7768         cache->ro = 0;
7769         spin_unlock(&cache->lock);
7770         spin_unlock(&sinfo->lock);
7771 }
7772
7773 /*
7774  * checks to see if its even possible to relocate this block group.
7775  *
7776  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7777  * ok to go ahead and try.
7778  */
7779 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7780 {
7781         struct btrfs_block_group_cache *block_group;
7782         struct btrfs_space_info *space_info;
7783         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7784         struct btrfs_device *device;
7785         u64 min_free;
7786         u64 dev_min = 1;
7787         u64 dev_nr = 0;
7788         u64 target;
7789         int index;
7790         int full = 0;
7791         int ret = 0;
7792
7793         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7794
7795         /* odd, couldn't find the block group, leave it alone */
7796         if (!block_group)
7797                 return -1;
7798
7799         min_free = btrfs_block_group_used(&block_group->item);
7800
7801         /* no bytes used, we're good */
7802         if (!min_free)
7803                 goto out;
7804
7805         space_info = block_group->space_info;
7806         spin_lock(&space_info->lock);
7807
7808         full = space_info->full;
7809
7810         /*
7811          * if this is the last block group we have in this space, we can't
7812          * relocate it unless we're able to allocate a new chunk below.
7813          *
7814          * Otherwise, we need to make sure we have room in the space to handle
7815          * all of the extents from this block group.  If we can, we're good
7816          */
7817         if ((space_info->total_bytes != block_group->key.offset) &&
7818             (space_info->bytes_used + space_info->bytes_reserved +
7819              space_info->bytes_pinned + space_info->bytes_readonly +
7820              min_free < space_info->total_bytes)) {
7821                 spin_unlock(&space_info->lock);
7822                 goto out;
7823         }
7824         spin_unlock(&space_info->lock);
7825
7826         /*
7827          * ok we don't have enough space, but maybe we have free space on our
7828          * devices to allocate new chunks for relocation, so loop through our
7829          * alloc devices and guess if we have enough space.  if this block
7830          * group is going to be restriped, run checks against the target
7831          * profile instead of the current one.
7832          */
7833         ret = -1;
7834
7835         /*
7836          * index:
7837          *      0: raid10
7838          *      1: raid1
7839          *      2: dup
7840          *      3: raid0
7841          *      4: single
7842          */
7843         target = get_restripe_target(root->fs_info, block_group->flags);
7844         if (target) {
7845                 index = __get_raid_index(extended_to_chunk(target));
7846         } else {
7847                 /*
7848                  * this is just a balance, so if we were marked as full
7849                  * we know there is no space for a new chunk
7850                  */
7851                 if (full)
7852                         goto out;
7853
7854                 index = get_block_group_index(block_group);
7855         }
7856
7857         if (index == BTRFS_RAID_RAID10) {
7858                 dev_min = 4;
7859                 /* Divide by 2 */
7860                 min_free >>= 1;
7861         } else if (index == BTRFS_RAID_RAID1) {
7862                 dev_min = 2;
7863         } else if (index == BTRFS_RAID_DUP) {
7864                 /* Multiply by 2 */
7865                 min_free <<= 1;
7866         } else if (index == BTRFS_RAID_RAID0) {
7867                 dev_min = fs_devices->rw_devices;
7868                 do_div(min_free, dev_min);
7869         }
7870
7871         mutex_lock(&root->fs_info->chunk_mutex);
7872         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7873                 u64 dev_offset;
7874
7875                 /*
7876                  * check to make sure we can actually find a chunk with enough
7877                  * space to fit our block group in.
7878                  */
7879                 if (device->total_bytes > device->bytes_used + min_free &&
7880                     !device->is_tgtdev_for_dev_replace) {
7881                         ret = find_free_dev_extent(device, min_free,
7882                                                    &dev_offset, NULL);
7883                         if (!ret)
7884                                 dev_nr++;
7885
7886                         if (dev_nr >= dev_min)
7887                                 break;
7888
7889                         ret = -1;
7890                 }
7891         }
7892         mutex_unlock(&root->fs_info->chunk_mutex);
7893 out:
7894         btrfs_put_block_group(block_group);
7895         return ret;
7896 }
7897
7898 static int find_first_block_group(struct btrfs_root *root,
7899                 struct btrfs_path *path, struct btrfs_key *key)
7900 {
7901         int ret = 0;
7902         struct btrfs_key found_key;
7903         struct extent_buffer *leaf;
7904         int slot;
7905
7906         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7907         if (ret < 0)
7908                 goto out;
7909
7910         while (1) {
7911                 slot = path->slots[0];
7912                 leaf = path->nodes[0];
7913                 if (slot >= btrfs_header_nritems(leaf)) {
7914                         ret = btrfs_next_leaf(root, path);
7915                         if (ret == 0)
7916                                 continue;
7917                         if (ret < 0)
7918                                 goto out;
7919                         break;
7920                 }
7921                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7922
7923                 if (found_key.objectid >= key->objectid &&
7924                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7925                         ret = 0;
7926                         goto out;
7927                 }
7928                 path->slots[0]++;
7929         }
7930 out:
7931         return ret;
7932 }
7933
7934 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7935 {
7936         struct btrfs_block_group_cache *block_group;
7937         u64 last = 0;
7938
7939         while (1) {
7940                 struct inode *inode;
7941
7942                 block_group = btrfs_lookup_first_block_group(info, last);
7943                 while (block_group) {
7944                         spin_lock(&block_group->lock);
7945                         if (block_group->iref)
7946                                 break;
7947                         spin_unlock(&block_group->lock);
7948                         block_group = next_block_group(info->tree_root,
7949                                                        block_group);
7950                 }
7951                 if (!block_group) {
7952                         if (last == 0)
7953                                 break;
7954                         last = 0;
7955                         continue;
7956                 }
7957
7958                 inode = block_group->inode;
7959                 block_group->iref = 0;
7960                 block_group->inode = NULL;
7961                 spin_unlock(&block_group->lock);
7962                 iput(inode);
7963                 last = block_group->key.objectid + block_group->key.offset;
7964                 btrfs_put_block_group(block_group);
7965         }
7966 }
7967
7968 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7969 {
7970         struct btrfs_block_group_cache *block_group;
7971         struct btrfs_space_info *space_info;
7972         struct btrfs_caching_control *caching_ctl;
7973         struct rb_node *n;
7974
7975         down_write(&info->extent_commit_sem);
7976         while (!list_empty(&info->caching_block_groups)) {
7977                 caching_ctl = list_entry(info->caching_block_groups.next,
7978                                          struct btrfs_caching_control, list);
7979                 list_del(&caching_ctl->list);
7980                 put_caching_control(caching_ctl);
7981         }
7982         up_write(&info->extent_commit_sem);
7983
7984         spin_lock(&info->block_group_cache_lock);
7985         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7986                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7987                                        cache_node);
7988                 rb_erase(&block_group->cache_node,
7989                          &info->block_group_cache_tree);
7990                 spin_unlock(&info->block_group_cache_lock);
7991
7992                 down_write(&block_group->space_info->groups_sem);
7993                 list_del(&block_group->list);
7994                 up_write(&block_group->space_info->groups_sem);
7995
7996                 if (block_group->cached == BTRFS_CACHE_STARTED)
7997                         wait_block_group_cache_done(block_group);
7998
7999                 /*
8000                  * We haven't cached this block group, which means we could
8001                  * possibly have excluded extents on this block group.
8002                  */
8003                 if (block_group->cached == BTRFS_CACHE_NO)
8004                         free_excluded_extents(info->extent_root, block_group);
8005
8006                 btrfs_remove_free_space_cache(block_group);
8007                 btrfs_put_block_group(block_group);
8008
8009                 spin_lock(&info->block_group_cache_lock);
8010         }
8011         spin_unlock(&info->block_group_cache_lock);
8012
8013         /* now that all the block groups are freed, go through and
8014          * free all the space_info structs.  This is only called during
8015          * the final stages of unmount, and so we know nobody is
8016          * using them.  We call synchronize_rcu() once before we start,
8017          * just to be on the safe side.
8018          */
8019         synchronize_rcu();
8020
8021         release_global_block_rsv(info);
8022
8023         while(!list_empty(&info->space_info)) {
8024                 space_info = list_entry(info->space_info.next,
8025                                         struct btrfs_space_info,
8026                                         list);
8027                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8028                         if (space_info->bytes_pinned > 0 ||
8029                             space_info->bytes_reserved > 0 ||
8030                             space_info->bytes_may_use > 0) {
8031                                 WARN_ON(1);
8032                                 dump_space_info(space_info, 0, 0);
8033                         }
8034                 }
8035                 list_del(&space_info->list);
8036                 kfree(space_info);
8037         }
8038         return 0;
8039 }
8040
8041 static void __link_block_group(struct btrfs_space_info *space_info,
8042                                struct btrfs_block_group_cache *cache)
8043 {
8044         int index = get_block_group_index(cache);
8045
8046         down_write(&space_info->groups_sem);
8047         list_add_tail(&cache->list, &space_info->block_groups[index]);
8048         up_write(&space_info->groups_sem);
8049 }
8050
8051 int btrfs_read_block_groups(struct btrfs_root *root)
8052 {
8053         struct btrfs_path *path;
8054         int ret;
8055         struct btrfs_block_group_cache *cache;
8056         struct btrfs_fs_info *info = root->fs_info;
8057         struct btrfs_space_info *space_info;
8058         struct btrfs_key key;
8059         struct btrfs_key found_key;
8060         struct extent_buffer *leaf;
8061         int need_clear = 0;
8062         u64 cache_gen;
8063
8064         root = info->extent_root;
8065         key.objectid = 0;
8066         key.offset = 0;
8067         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
8068         path = btrfs_alloc_path();
8069         if (!path)
8070                 return -ENOMEM;
8071         path->reada = 1;
8072
8073         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
8074         if (btrfs_test_opt(root, SPACE_CACHE) &&
8075             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
8076                 need_clear = 1;
8077         if (btrfs_test_opt(root, CLEAR_CACHE))
8078                 need_clear = 1;
8079
8080         while (1) {
8081                 ret = find_first_block_group(root, path, &key);
8082                 if (ret > 0)
8083                         break;
8084                 if (ret != 0)
8085                         goto error;
8086                 leaf = path->nodes[0];
8087                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8088                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
8089                 if (!cache) {
8090                         ret = -ENOMEM;
8091                         goto error;
8092                 }
8093                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8094                                                 GFP_NOFS);
8095                 if (!cache->free_space_ctl) {
8096                         kfree(cache);
8097                         ret = -ENOMEM;
8098                         goto error;
8099                 }
8100
8101                 atomic_set(&cache->count, 1);
8102                 spin_lock_init(&cache->lock);
8103                 cache->fs_info = info;
8104                 INIT_LIST_HEAD(&cache->list);
8105                 INIT_LIST_HEAD(&cache->cluster_list);
8106
8107                 if (need_clear) {
8108                         /*
8109                          * When we mount with old space cache, we need to
8110                          * set BTRFS_DC_CLEAR and set dirty flag.
8111                          *
8112                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
8113                          *    truncate the old free space cache inode and
8114                          *    setup a new one.
8115                          * b) Setting 'dirty flag' makes sure that we flush
8116                          *    the new space cache info onto disk.
8117                          */
8118                         cache->disk_cache_state = BTRFS_DC_CLEAR;
8119                         if (btrfs_test_opt(root, SPACE_CACHE))
8120                                 cache->dirty = 1;
8121                 }
8122
8123                 read_extent_buffer(leaf, &cache->item,
8124                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
8125                                    sizeof(cache->item));
8126                 memcpy(&cache->key, &found_key, sizeof(found_key));
8127
8128                 key.objectid = found_key.objectid + found_key.offset;
8129                 btrfs_release_path(path);
8130                 cache->flags = btrfs_block_group_flags(&cache->item);
8131                 cache->sectorsize = root->sectorsize;
8132                 cache->full_stripe_len = btrfs_full_stripe_len(root,
8133                                                &root->fs_info->mapping_tree,
8134                                                found_key.objectid);
8135                 btrfs_init_free_space_ctl(cache);
8136
8137                 /*
8138                  * We need to exclude the super stripes now so that the space
8139                  * info has super bytes accounted for, otherwise we'll think
8140                  * we have more space than we actually do.
8141                  */
8142                 ret = exclude_super_stripes(root, cache);
8143                 if (ret) {
8144                         /*
8145                          * We may have excluded something, so call this just in
8146                          * case.
8147                          */
8148                         free_excluded_extents(root, cache);
8149                         kfree(cache->free_space_ctl);
8150                         kfree(cache);
8151                         goto error;
8152                 }
8153
8154                 /*
8155                  * check for two cases, either we are full, and therefore
8156                  * don't need to bother with the caching work since we won't
8157                  * find any space, or we are empty, and we can just add all
8158                  * the space in and be done with it.  This saves us _alot_ of
8159                  * time, particularly in the full case.
8160                  */
8161                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
8162                         cache->last_byte_to_unpin = (u64)-1;
8163                         cache->cached = BTRFS_CACHE_FINISHED;
8164                         free_excluded_extents(root, cache);
8165                 } else if (btrfs_block_group_used(&cache->item) == 0) {
8166                         cache->last_byte_to_unpin = (u64)-1;
8167                         cache->cached = BTRFS_CACHE_FINISHED;
8168                         add_new_free_space(cache, root->fs_info,
8169                                            found_key.objectid,
8170                                            found_key.objectid +
8171                                            found_key.offset);
8172                         free_excluded_extents(root, cache);
8173                 }
8174
8175                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8176                 if (ret) {
8177                         btrfs_remove_free_space_cache(cache);
8178                         btrfs_put_block_group(cache);
8179                         goto error;
8180                 }
8181
8182                 ret = update_space_info(info, cache->flags, found_key.offset,
8183                                         btrfs_block_group_used(&cache->item),
8184                                         &space_info);
8185                 if (ret) {
8186                         btrfs_remove_free_space_cache(cache);
8187                         spin_lock(&info->block_group_cache_lock);
8188                         rb_erase(&cache->cache_node,
8189                                  &info->block_group_cache_tree);
8190                         spin_unlock(&info->block_group_cache_lock);
8191                         btrfs_put_block_group(cache);
8192                         goto error;
8193                 }
8194
8195                 cache->space_info = space_info;
8196                 spin_lock(&cache->space_info->lock);
8197                 cache->space_info->bytes_readonly += cache->bytes_super;
8198                 spin_unlock(&cache->space_info->lock);
8199
8200                 __link_block_group(space_info, cache);
8201
8202                 set_avail_alloc_bits(root->fs_info, cache->flags);
8203                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8204                         set_block_group_ro(cache, 1);
8205         }
8206
8207         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8208                 if (!(get_alloc_profile(root, space_info->flags) &
8209                       (BTRFS_BLOCK_GROUP_RAID10 |
8210                        BTRFS_BLOCK_GROUP_RAID1 |
8211                        BTRFS_BLOCK_GROUP_RAID5 |
8212                        BTRFS_BLOCK_GROUP_RAID6 |
8213                        BTRFS_BLOCK_GROUP_DUP)))
8214                         continue;
8215                 /*
8216                  * avoid allocating from un-mirrored block group if there are
8217                  * mirrored block groups.
8218                  */
8219                 list_for_each_entry(cache, &space_info->block_groups[3], list)
8220                         set_block_group_ro(cache, 1);
8221                 list_for_each_entry(cache, &space_info->block_groups[4], list)
8222                         set_block_group_ro(cache, 1);
8223         }
8224
8225         init_global_block_rsv(info);
8226         ret = 0;
8227 error:
8228         btrfs_free_path(path);
8229         return ret;
8230 }
8231
8232 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
8233                                        struct btrfs_root *root)
8234 {
8235         struct btrfs_block_group_cache *block_group, *tmp;
8236         struct btrfs_root *extent_root = root->fs_info->extent_root;
8237         struct btrfs_block_group_item item;
8238         struct btrfs_key key;
8239         int ret = 0;
8240
8241         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
8242                                  new_bg_list) {
8243                 list_del_init(&block_group->new_bg_list);
8244
8245                 if (ret)
8246                         continue;
8247
8248                 spin_lock(&block_group->lock);
8249                 memcpy(&item, &block_group->item, sizeof(item));
8250                 memcpy(&key, &block_group->key, sizeof(key));
8251                 spin_unlock(&block_group->lock);
8252
8253                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
8254                                         sizeof(item));
8255                 if (ret)
8256                         btrfs_abort_transaction(trans, extent_root, ret);
8257         }
8258 }
8259
8260 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8261                            struct btrfs_root *root, u64 bytes_used,
8262                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8263                            u64 size)
8264 {
8265         int ret;
8266         struct btrfs_root *extent_root;
8267         struct btrfs_block_group_cache *cache;
8268
8269         extent_root = root->fs_info->extent_root;
8270
8271         root->fs_info->last_trans_log_full_commit = trans->transid;
8272
8273         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8274         if (!cache)
8275                 return -ENOMEM;
8276         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8277                                         GFP_NOFS);
8278         if (!cache->free_space_ctl) {
8279                 kfree(cache);
8280                 return -ENOMEM;
8281         }
8282
8283         cache->key.objectid = chunk_offset;
8284         cache->key.offset = size;
8285         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8286         cache->sectorsize = root->sectorsize;
8287         cache->fs_info = root->fs_info;
8288         cache->full_stripe_len = btrfs_full_stripe_len(root,
8289                                                &root->fs_info->mapping_tree,
8290                                                chunk_offset);
8291
8292         atomic_set(&cache->count, 1);
8293         spin_lock_init(&cache->lock);
8294         INIT_LIST_HEAD(&cache->list);
8295         INIT_LIST_HEAD(&cache->cluster_list);
8296         INIT_LIST_HEAD(&cache->new_bg_list);
8297
8298         btrfs_init_free_space_ctl(cache);
8299
8300         btrfs_set_block_group_used(&cache->item, bytes_used);
8301         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8302         cache->flags = type;
8303         btrfs_set_block_group_flags(&cache->item, type);
8304
8305         cache->last_byte_to_unpin = (u64)-1;
8306         cache->cached = BTRFS_CACHE_FINISHED;
8307         ret = exclude_super_stripes(root, cache);
8308         if (ret) {
8309                 /*
8310                  * We may have excluded something, so call this just in
8311                  * case.
8312                  */
8313                 free_excluded_extents(root, cache);
8314                 kfree(cache->free_space_ctl);
8315                 kfree(cache);
8316                 return ret;
8317         }
8318
8319         add_new_free_space(cache, root->fs_info, chunk_offset,
8320                            chunk_offset + size);
8321
8322         free_excluded_extents(root, cache);
8323
8324         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8325         if (ret) {
8326                 btrfs_remove_free_space_cache(cache);
8327                 btrfs_put_block_group(cache);
8328                 return ret;
8329         }
8330
8331         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8332                                 &cache->space_info);
8333         if (ret) {
8334                 btrfs_remove_free_space_cache(cache);
8335                 spin_lock(&root->fs_info->block_group_cache_lock);
8336                 rb_erase(&cache->cache_node,
8337                          &root->fs_info->block_group_cache_tree);
8338                 spin_unlock(&root->fs_info->block_group_cache_lock);
8339                 btrfs_put_block_group(cache);
8340                 return ret;
8341         }
8342         update_global_block_rsv(root->fs_info);
8343
8344         spin_lock(&cache->space_info->lock);
8345         cache->space_info->bytes_readonly += cache->bytes_super;
8346         spin_unlock(&cache->space_info->lock);
8347
8348         __link_block_group(cache->space_info, cache);
8349
8350         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
8351
8352         set_avail_alloc_bits(extent_root->fs_info, type);
8353
8354         return 0;
8355 }
8356
8357 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
8358 {
8359         u64 extra_flags = chunk_to_extended(flags) &
8360                                 BTRFS_EXTENDED_PROFILE_MASK;
8361
8362         write_seqlock(&fs_info->profiles_lock);
8363         if (flags & BTRFS_BLOCK_GROUP_DATA)
8364                 fs_info->avail_data_alloc_bits &= ~extra_flags;
8365         if (flags & BTRFS_BLOCK_GROUP_METADATA)
8366                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
8367         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
8368                 fs_info->avail_system_alloc_bits &= ~extra_flags;
8369         write_sequnlock(&fs_info->profiles_lock);
8370 }
8371
8372 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8373                              struct btrfs_root *root, u64 group_start)
8374 {
8375         struct btrfs_path *path;
8376         struct btrfs_block_group_cache *block_group;
8377         struct btrfs_free_cluster *cluster;
8378         struct btrfs_root *tree_root = root->fs_info->tree_root;
8379         struct btrfs_key key;
8380         struct inode *inode;
8381         int ret;
8382         int index;
8383         int factor;
8384
8385         root = root->fs_info->extent_root;
8386
8387         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8388         BUG_ON(!block_group);
8389         BUG_ON(!block_group->ro);
8390
8391         /*
8392          * Free the reserved super bytes from this block group before
8393          * remove it.
8394          */
8395         free_excluded_extents(root, block_group);
8396
8397         memcpy(&key, &block_group->key, sizeof(key));
8398         index = get_block_group_index(block_group);
8399         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
8400                                   BTRFS_BLOCK_GROUP_RAID1 |
8401                                   BTRFS_BLOCK_GROUP_RAID10))
8402                 factor = 2;
8403         else
8404                 factor = 1;
8405
8406         /* make sure this block group isn't part of an allocation cluster */
8407         cluster = &root->fs_info->data_alloc_cluster;
8408         spin_lock(&cluster->refill_lock);
8409         btrfs_return_cluster_to_free_space(block_group, cluster);
8410         spin_unlock(&cluster->refill_lock);
8411
8412         /*
8413          * make sure this block group isn't part of a metadata
8414          * allocation cluster
8415          */
8416         cluster = &root->fs_info->meta_alloc_cluster;
8417         spin_lock(&cluster->refill_lock);
8418         btrfs_return_cluster_to_free_space(block_group, cluster);
8419         spin_unlock(&cluster->refill_lock);
8420
8421         path = btrfs_alloc_path();
8422         if (!path) {
8423                 ret = -ENOMEM;
8424                 goto out;
8425         }
8426
8427         inode = lookup_free_space_inode(tree_root, block_group, path);
8428         if (!IS_ERR(inode)) {
8429                 ret = btrfs_orphan_add(trans, inode);
8430                 if (ret) {
8431                         btrfs_add_delayed_iput(inode);
8432                         goto out;
8433                 }
8434                 clear_nlink(inode);
8435                 /* One for the block groups ref */
8436                 spin_lock(&block_group->lock);
8437                 if (block_group->iref) {
8438                         block_group->iref = 0;
8439                         block_group->inode = NULL;
8440                         spin_unlock(&block_group->lock);
8441                         iput(inode);
8442                 } else {
8443                         spin_unlock(&block_group->lock);
8444                 }
8445                 /* One for our lookup ref */
8446                 btrfs_add_delayed_iput(inode);
8447         }
8448
8449         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8450         key.offset = block_group->key.objectid;
8451         key.type = 0;
8452
8453         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8454         if (ret < 0)
8455                 goto out;
8456         if (ret > 0)
8457                 btrfs_release_path(path);
8458         if (ret == 0) {
8459                 ret = btrfs_del_item(trans, tree_root, path);
8460                 if (ret)
8461                         goto out;
8462                 btrfs_release_path(path);
8463         }
8464
8465         spin_lock(&root->fs_info->block_group_cache_lock);
8466         rb_erase(&block_group->cache_node,
8467                  &root->fs_info->block_group_cache_tree);
8468
8469         if (root->fs_info->first_logical_byte == block_group->key.objectid)
8470                 root->fs_info->first_logical_byte = (u64)-1;
8471         spin_unlock(&root->fs_info->block_group_cache_lock);
8472
8473         down_write(&block_group->space_info->groups_sem);
8474         /*
8475          * we must use list_del_init so people can check to see if they
8476          * are still on the list after taking the semaphore
8477          */
8478         list_del_init(&block_group->list);
8479         if (list_empty(&block_group->space_info->block_groups[index]))
8480                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8481         up_write(&block_group->space_info->groups_sem);
8482
8483         if (block_group->cached == BTRFS_CACHE_STARTED)
8484                 wait_block_group_cache_done(block_group);
8485
8486         btrfs_remove_free_space_cache(block_group);
8487
8488         spin_lock(&block_group->space_info->lock);
8489         block_group->space_info->total_bytes -= block_group->key.offset;
8490         block_group->space_info->bytes_readonly -= block_group->key.offset;
8491         block_group->space_info->disk_total -= block_group->key.offset * factor;
8492         spin_unlock(&block_group->space_info->lock);
8493
8494         memcpy(&key, &block_group->key, sizeof(key));
8495
8496         btrfs_clear_space_info_full(root->fs_info);
8497
8498         btrfs_put_block_group(block_group);
8499         btrfs_put_block_group(block_group);
8500
8501         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8502         if (ret > 0)
8503                 ret = -EIO;
8504         if (ret < 0)
8505                 goto out;
8506
8507         ret = btrfs_del_item(trans, root, path);
8508 out:
8509         btrfs_free_path(path);
8510         return ret;
8511 }
8512
8513 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8514 {
8515         struct btrfs_space_info *space_info;
8516         struct btrfs_super_block *disk_super;
8517         u64 features;
8518         u64 flags;
8519         int mixed = 0;
8520         int ret;
8521
8522         disk_super = fs_info->super_copy;
8523         if (!btrfs_super_root(disk_super))
8524                 return 1;
8525
8526         features = btrfs_super_incompat_flags(disk_super);
8527         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8528                 mixed = 1;
8529
8530         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8531         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8532         if (ret)
8533                 goto out;
8534
8535         if (mixed) {
8536                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8537                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8538         } else {
8539                 flags = BTRFS_BLOCK_GROUP_METADATA;
8540                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8541                 if (ret)
8542                         goto out;
8543
8544                 flags = BTRFS_BLOCK_GROUP_DATA;
8545                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8546         }
8547 out:
8548         return ret;
8549 }
8550
8551 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8552 {
8553         return unpin_extent_range(root, start, end);
8554 }
8555
8556 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8557                                u64 num_bytes, u64 *actual_bytes)
8558 {
8559         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8560 }
8561
8562 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8563 {
8564         struct btrfs_fs_info *fs_info = root->fs_info;
8565         struct btrfs_block_group_cache *cache = NULL;
8566         u64 group_trimmed;
8567         u64 start;
8568         u64 end;
8569         u64 trimmed = 0;
8570         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8571         int ret = 0;
8572
8573         /*
8574          * try to trim all FS space, our block group may start from non-zero.
8575          */
8576         if (range->len == total_bytes)
8577                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8578         else
8579                 cache = btrfs_lookup_block_group(fs_info, range->start);
8580
8581         while (cache) {
8582                 if (cache->key.objectid >= (range->start + range->len)) {
8583                         btrfs_put_block_group(cache);
8584                         break;
8585                 }
8586
8587                 start = max(range->start, cache->key.objectid);
8588                 end = min(range->start + range->len,
8589                                 cache->key.objectid + cache->key.offset);
8590
8591                 if (end - start >= range->minlen) {
8592                         if (!block_group_cache_done(cache)) {
8593                                 ret = cache_block_group(cache, 0);
8594                                 if (!ret)
8595                                         wait_block_group_cache_done(cache);
8596                         }
8597                         ret = btrfs_trim_block_group(cache,
8598                                                      &group_trimmed,
8599                                                      start,
8600                                                      end,
8601                                                      range->minlen);
8602
8603                         trimmed += group_trimmed;
8604                         if (ret) {
8605                                 btrfs_put_block_group(cache);
8606                                 break;
8607                         }
8608                 }
8609
8610                 cache = next_block_group(fs_info->tree_root, cache);
8611         }
8612
8613         range->len = trimmed;
8614         return ret;
8615 }