fs/btrfs/extent-tree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/signal.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/writeback.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/sort.h>
  12 #include <linux/rcupdate.h>
  13 #include <linux/kthread.h>
  14 #include <linux/slab.h>
  15 #include <linux/ratelimit.h>
  16 #include <linux/percpu_counter.h>
  17 #include <linux/lockdep.h>
  18 #include <linux/crc32c.h>
  19 #include "misc.h"
  20 #include "tree-log.h"
  21 #include "disk-io.h"
  22 #include "print-tree.h"
  23 #include "volumes.h"
  24 #include "raid56.h"
  25 #include "locking.h"
  26 #include "free-space-cache.h"
  27 #include "free-space-tree.h"
  28 #include "sysfs.h"
  29 #include "qgroup.h"
  30 #include "ref-verify.h"
  31 #include "space-info.h"
  32 #include "block-rsv.h"
  33 #include "delalloc-space.h"
  34 #include "block-group.h"
  35 #include "discard.h"
  36 #include "rcu-string.h"
  37
  38 #undef SCRAMBLE_DELAYED_REFS
  39
  40
  41 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  42                                struct btrfs_delayed_ref_node *node, u64 parent,
  43                                u64 root_objectid, u64 owner_objectid,
  44                                u64 owner_offset, int refs_to_drop,
  45                                struct btrfs_delayed_extent_op *extra_op);
  46 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  47                                     struct extent_buffer *leaf,
  48                                     struct btrfs_extent_item *ei);
  49 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  50                                       u64 parent, u64 root_objectid,
  51                                       u64 flags, u64 owner, u64 offset,
  52                                       struct btrfs_key *ins, int ref_mod);
  53 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  54                                      struct btrfs_delayed_ref_node *node,
  55                                      struct btrfs_delayed_extent_op *extent_op);
  56 static int find_next_key(struct btrfs_path *path, int level,
  57                          struct btrfs_key *key);
  58
  59 static int block_group_bits(struct btrfs_block_group *cache, u64 bits)
  60 {
  61         return (cache->flags & bits) == bits;
  62 }
  63
  64 int btrfs_add_excluded_extent(struct btrfs_fs_info *fs_info,
  65                               u64 start, u64 num_bytes)
  66 {
  67         u64 end = start + num_bytes - 1;
  68         set_extent_bits(&fs_info->excluded_extents, start, end,
  69                         EXTENT_UPTODATE);
  70         return 0;
  71 }
  72
  73 void btrfs_free_excluded_extents(struct btrfs_block_group *cache)
  74 {
  75         struct btrfs_fs_info *fs_info = cache->fs_info;
  76         u64 start, end;
  77
  78         start = cache->start;
  79         end = start + cache->length - 1;
  80
  81         clear_extent_bits(&fs_info->excluded_extents, start, end,
  82                           EXTENT_UPTODATE);
  83 }
  84
  85 static u64 generic_ref_to_space_flags(struct btrfs_ref *ref)
  86 {
  87         if (ref->type == BTRFS_REF_METADATA) {
  88                 if (ref->tree_ref.root == BTRFS_CHUNK_TREE_OBJECTID)
  89                         return BTRFS_BLOCK_GROUP_SYSTEM;
  90                 else
  91                         return BTRFS_BLOCK_GROUP_METADATA;
  92         }
  93         return BTRFS_BLOCK_GROUP_DATA;
  94 }
  95
  96 static void add_pinned_bytes(struct btrfs_fs_info *fs_info,
  97                              struct btrfs_ref *ref)
  98 {
  99         struct btrfs_space_info *space_info;
 100         u64 flags = generic_ref_to_space_flags(ref);
 101
 102         space_info = btrfs_find_space_info(fs_info, flags);
 103         ASSERT(space_info);
 104         percpu_counter_add_batch(&space_info->total_bytes_pinned, ref->len,
 105                     BTRFS_TOTAL_BYTES_PINNED_BATCH);
 106 }
 107
 108 static void sub_pinned_bytes(struct btrfs_fs_info *fs_info,
 109                              struct btrfs_ref *ref)
 110 {
 111         struct btrfs_space_info *space_info;
 112         u64 flags = generic_ref_to_space_flags(ref);
 113
 114         space_info = btrfs_find_space_info(fs_info, flags);
 115         ASSERT(space_info);
 116         percpu_counter_add_batch(&space_info->total_bytes_pinned, -ref->len,
 117                     BTRFS_TOTAL_BYTES_PINNED_BATCH);
 118 }
 119
 120 /* simple helper to search for an existing data extent at a given offset */
 121 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 122 {
 123         int ret;
 124         struct btrfs_key key;
 125         struct btrfs_path *path;
 126
 127         path = btrfs_alloc_path();
 128         if (!path)
 129                 return -ENOMEM;
 130
 131         key.objectid = start;
 132         key.offset = len;
 133         key.type = BTRFS_EXTENT_ITEM_KEY;
 134         ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 135         btrfs_free_path(path);
 136         return ret;
 137 }
 138
 139 /*
 140  * helper function to lookup reference count and flags of a tree block.
 141  *
 142  * the head node for delayed ref is used to store the sum of all the
 143  * reference count modifications queued up in the rbtree. the head
 144  * node may also store the extent flags to set. This way you can check
 145  * to see what the reference count and extent flags would be if all of
 146  * the delayed refs are not processed.
 147  */
 148 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 149                              struct btrfs_fs_info *fs_info, u64 bytenr,
 150                              u64 offset, int metadata, u64 *refs, u64 *flags)
 151 {
 152         struct btrfs_delayed_ref_head *head;
 153         struct btrfs_delayed_ref_root *delayed_refs;
 154         struct btrfs_path *path;
 155         struct btrfs_extent_item *ei;
 156         struct extent_buffer *leaf;
 157         struct btrfs_key key;
 158         u32 item_size;
 159         u64 num_refs;
 160         u64 extent_flags;
 161         int ret;
 162
 163         /*
 164          * If we don't have skinny metadata, don't bother doing anything
 165          * different
 166          */
 167         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 168                 offset = fs_info->nodesize;
 169                 metadata = 0;
 170         }
 171
 172         path = btrfs_alloc_path();
 173         if (!path)
 174                 return -ENOMEM;
 175
 176         if (!trans) {
 177                 path->skip_locking = 1;
 178                 path->search_commit_root = 1;
 179         }
 180
 181 search_again:
 182         key.objectid = bytenr;
 183         key.offset = offset;
 184         if (metadata)
 185                 key.type = BTRFS_METADATA_ITEM_KEY;
 186         else
 187                 key.type = BTRFS_EXTENT_ITEM_KEY;
 188
 189         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 190         if (ret < 0)
 191                 goto out_free;
 192
 193         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 194                 if (path->slots[0]) {
 195                         path->slots[0]--;
 196                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 197                                               path->slots[0]);
 198                         if (key.objectid == bytenr &&
 199                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 200                             key.offset == fs_info->nodesize)
 201                                 ret = 0;
 202                 }
 203         }
 204
 205         if (ret == 0) {
 206                 leaf = path->nodes[0];
 207                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 208                 if (item_size >= sizeof(*ei)) {
 209                         ei = btrfs_item_ptr(leaf, path->slots[0],
 210                                             struct btrfs_extent_item);
 211                         num_refs = btrfs_extent_refs(leaf, ei);
 212                         extent_flags = btrfs_extent_flags(leaf, ei);
 213                 } else {
 214                         ret = -EINVAL;
 215                         btrfs_print_v0_err(fs_info);
 216                         if (trans)
 217                                 btrfs_abort_transaction(trans, ret);
 218                         else
 219                                 btrfs_handle_fs_error(fs_info, ret, NULL);
 220
 221                         goto out_free;
 222                 }
 223
 224                 BUG_ON(num_refs == 0);
 225         } else {
 226                 num_refs = 0;
 227                 extent_flags = 0;
 228                 ret = 0;
 229         }
 230
 231         if (!trans)
 232                 goto out;
 233
 234         delayed_refs = &trans->transaction->delayed_refs;
 235         spin_lock(&delayed_refs->lock);
 236         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 237         if (head) {
 238                 if (!mutex_trylock(&head->mutex)) {
 239                         refcount_inc(&head->refs);
 240                         spin_unlock(&delayed_refs->lock);
 241
 242                         btrfs_release_path(path);
 243
 244                         /*
 245                          * Mutex was contended, block until it's released and try
 246                          * again
 247                          */
 248                         mutex_lock(&head->mutex);
 249                         mutex_unlock(&head->mutex);
 250                         btrfs_put_delayed_ref_head(head);
 251                         goto search_again;
 252                 }
 253                 spin_lock(&head->lock);
 254                 if (head->extent_op && head->extent_op->update_flags)
 255                         extent_flags |= head->extent_op->flags_to_set;
 256                 else
 257                         BUG_ON(num_refs == 0);
 258
 259                 num_refs += head->ref_mod;
 260                 spin_unlock(&head->lock);
 261                 mutex_unlock(&head->mutex);
 262         }
 263         spin_unlock(&delayed_refs->lock);
 264 out:
 265         WARN_ON(num_refs == 0);
 266         if (refs)
 267                 *refs = num_refs;
 268         if (flags)
 269                 *flags = extent_flags;
 270 out_free:
 271         btrfs_free_path(path);
 272         return ret;
 273 }
 274
 275 /*
 276  * Back reference rules.  Back refs have three main goals:
 277  *
 278  * 1) differentiate between all holders of references to an extent so that
 279  *    when a reference is dropped we can make sure it was a valid reference
 280  *    before freeing the extent.
 281  *
 282  * 2) Provide enough information to quickly find the holders of an extent
 283  *    if we notice a given block is corrupted or bad.
 284  *
 285  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 286  *    maintenance.  This is actually the same as #2, but with a slightly
 287  *    different use case.
 288  *
 289  * There are two kinds of back refs. The implicit back refs is optimized
 290  * for pointers in non-shared tree blocks. For a given pointer in a block,
 291  * back refs of this kind provide information about the block's owner tree
 292  * and the pointer's key. These information allow us to find the block by
 293  * b-tree searching. The full back refs is for pointers in tree blocks not
 294  * referenced by their owner trees. The location of tree block is recorded
 295  * in the back refs. Actually the full back refs is generic, and can be
 296  * used in all cases the implicit back refs is used. The major shortcoming
 297  * of the full back refs is its overhead. Every time a tree block gets
 298  * COWed, we have to update back refs entry for all pointers in it.
 299  *
 300  * For a newly allocated tree block, we use implicit back refs for
 301  * pointers in it. This means most tree related operations only involve
 302  * implicit back refs. For a tree block created in old transaction, the
 303  * only way to drop a reference to it is COW it. So we can detect the
 304  * event that tree block loses its owner tree's reference and do the
 305  * back refs conversion.
 306  *
 307  * When a tree block is COWed through a tree, there are four cases:
 308  *
 309  * The reference count of the block is one and the tree is the block's
 310  * owner tree. Nothing to do in this case.
 311  *
 312  * The reference count of the block is one and the tree is not the
 313  * block's owner tree. In this case, full back refs is used for pointers
 314  * in the block. Remove these full back refs, add implicit back refs for
 315  * every pointers in the new block.
 316  *
 317  * The reference count of the block is greater than one and the tree is
 318  * the block's owner tree. In this case, implicit back refs is used for
 319  * pointers in the block. Add full back refs for every pointers in the
 320  * block, increase lower level extents' reference counts. The original
 321  * implicit back refs are entailed to the new block.
 322  *
 323  * The reference count of the block is greater than one and the tree is
 324  * not the block's owner tree. Add implicit back refs for every pointer in
 325  * the new block, increase lower level extents' reference count.
 326  *
 327  * Back Reference Key composing:
 328  *
 329  * The key objectid corresponds to the first byte in the extent,
 330  * The key type is used to differentiate between types of back refs.
 331  * There are different meanings of the key offset for different types
 332  * of back refs.
 333  *
 334  * File extents can be referenced by:
 335  *
 336  * - multiple snapshots, subvolumes, or different generations in one subvol
 337  * - different files inside a single subvolume
 338  * - different offsets inside a file (bookend extents in file.c)
 339  *
 340  * The extent ref structure for the implicit back refs has fields for:
 341  *
 342  * - Objectid of the subvolume root
 343  * - objectid of the file holding the reference
 344  * - original offset in the file
 345  * - how many bookend extents
 346  *
 347  * The key offset for the implicit back refs is hash of the first
 348  * three fields.
 349  *
 350  * The extent ref structure for the full back refs has field for:
 351  *
 352  * - number of pointers in the tree leaf
 353  *
 354  * The key offset for the implicit back refs is the first byte of
 355  * the tree leaf
 356  *
 357  * When a file extent is allocated, The implicit back refs is used.
 358  * the fields are filled in:
 359  *
 360  *     (root_key.objectid, inode objectid, offset in file, 1)
 361  *
 362  * When a file extent is removed file truncation, we find the
 363  * corresponding implicit back refs and check the following fields:
 364  *
 365  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 366  *
 367  * Btree extents can be referenced by:
 368  *
 369  * - Different subvolumes
 370  *
 371  * Both the implicit back refs and the full back refs for tree blocks
 372  * only consist of key. The key offset for the implicit back refs is
 373  * objectid of block's owner tree. The key offset for the full back refs
 374  * is the first byte of parent block.
 375  *
 376  * When implicit back refs is used, information about the lowest key and
 377  * level of the tree block are required. These information are stored in
 378  * tree block info structure.
 379  */
 380
 381 /*
 382  * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
 383  * is_data == BTRFS_REF_TYPE_DATA, data type is requiried,
 384  * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
 385  */
 386 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
 387                                      struct btrfs_extent_inline_ref *iref,
 388                                      enum btrfs_inline_ref_type is_data)
 389 {
 390         int type = btrfs_extent_inline_ref_type(eb, iref);
 391         u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
 392
 393         if (type == BTRFS_TREE_BLOCK_REF_KEY ||
 394             type == BTRFS_SHARED_BLOCK_REF_KEY ||
 395             type == BTRFS_SHARED_DATA_REF_KEY ||
 396             type == BTRFS_EXTENT_DATA_REF_KEY) {
 397                 if (is_data == BTRFS_REF_TYPE_BLOCK) {
 398                         if (type == BTRFS_TREE_BLOCK_REF_KEY)
 399                                 return type;
 400                         if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
 401                                 ASSERT(eb->fs_info);
 402                                 /*
 403                                  * Every shared one has parent tree
 404                                  * block, which must be aligned to
 405                                  * nodesize.
 406                                  */
 407                                 if (offset &&
 408                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
 409                                         return type;
 410                         }
 411                 } else if (is_data == BTRFS_REF_TYPE_DATA) {
 412                         if (type == BTRFS_EXTENT_DATA_REF_KEY)
 413                                 return type;
 414                         if (type == BTRFS_SHARED_DATA_REF_KEY) {
 415                                 ASSERT(eb->fs_info);
 416                                 /*
 417                                  * Every shared one has parent tree
 418                                  * block, which must be aligned to
 419                                  * nodesize.
 420                                  */
 421                                 if (offset &&
 422                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
 423                                         return type;
 424                         }
 425                 } else {
 426                         ASSERT(is_data == BTRFS_REF_TYPE_ANY);
 427                         return type;
 428                 }
 429         }
 430
 431         btrfs_print_leaf((struct extent_buffer *)eb);
 432         btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
 433                   eb->start, type);
 434         WARN_ON(1);
 435
 436         return BTRFS_REF_TYPE_INVALID;
 437 }
 438
 439 u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 440 {
 441         u32 high_crc = ~(u32)0;
 442         u32 low_crc = ~(u32)0;
 443         __le64 lenum;
 444
 445         lenum = cpu_to_le64(root_objectid);
 446         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
 447         lenum = cpu_to_le64(owner);
 448         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 449         lenum = cpu_to_le64(offset);
 450         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 451
 452         return ((u64)high_crc << 31) ^ (u64)low_crc;
 453 }
 454
 455 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 456                                      struct btrfs_extent_data_ref *ref)
 457 {
 458         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 459                                     btrfs_extent_data_ref_objectid(leaf, ref),
 460                                     btrfs_extent_data_ref_offset(leaf, ref));
 461 }
 462
 463 static int match_extent_data_ref(struct extent_buffer *leaf,
 464                                  struct btrfs_extent_data_ref *ref,
 465                                  u64 root_objectid, u64 owner, u64 offset)
 466 {
 467         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
 468             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
 469             btrfs_extent_data_ref_offset(leaf, ref) != offset)
 470                 return 0;
 471         return 1;
 472 }
 473
 474 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 475                                            struct btrfs_path *path,
 476                                            u64 bytenr, u64 parent,
 477                                            u64 root_objectid,
 478                                            u64 owner, u64 offset)
 479 {
 480         struct btrfs_root *root = trans->fs_info->extent_root;
 481         struct btrfs_key key;
 482         struct btrfs_extent_data_ref *ref;
 483         struct extent_buffer *leaf;
 484         u32 nritems;
 485         int ret;
 486         int recow;
 487         int err = -ENOENT;
 488
 489         key.objectid = bytenr;
 490         if (parent) {
 491                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 492                 key.offset = parent;
 493         } else {
 494                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 495                 key.offset = hash_extent_data_ref(root_objectid,
 496                                                   owner, offset);
 497         }
 498 again:
 499         recow = 0;
 500         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 501         if (ret < 0) {
 502                 err = ret;
 503                 goto fail;
 504         }
 505
 506         if (parent) {
 507                 if (!ret)
 508                         return 0;
 509                 goto fail;
 510         }
 511
 512         leaf = path->nodes[0];
 513         nritems = btrfs_header_nritems(leaf);
 514         while (1) {
 515                 if (path->slots[0] >= nritems) {
 516                         ret = btrfs_next_leaf(root, path);
 517                         if (ret < 0)
 518                                 err = ret;
 519                         if (ret)
 520                                 goto fail;
 521
 522                         leaf = path->nodes[0];
 523                         nritems = btrfs_header_nritems(leaf);
 524                         recow = 1;
 525                 }
 526
 527                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 528                 if (key.objectid != bytenr ||
 529                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
 530                         goto fail;
 531
 532                 ref = btrfs_item_ptr(leaf, path->slots[0],
 533                                      struct btrfs_extent_data_ref);
 534
 535                 if (match_extent_data_ref(leaf, ref, root_objectid,
 536                                           owner, offset)) {
 537                         if (recow) {
 538                                 btrfs_release_path(path);
 539                                 goto again;
 540                         }
 541                         err = 0;
 542                         break;
 543                 }
 544                 path->slots[0]++;
 545         }
 546 fail:
 547         return err;
 548 }
 549
 550 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
 551                                            struct btrfs_path *path,
 552                                            u64 bytenr, u64 parent,
 553                                            u64 root_objectid, u64 owner,
 554                                            u64 offset, int refs_to_add)
 555 {
 556         struct btrfs_root *root = trans->fs_info->extent_root;
 557         struct btrfs_key key;
 558         struct extent_buffer *leaf;
 559         u32 size;
 560         u32 num_refs;
 561         int ret;
 562
 563         key.objectid = bytenr;
 564         if (parent) {
 565                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 566                 key.offset = parent;
 567                 size = sizeof(struct btrfs_shared_data_ref);
 568         } else {
 569                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 570                 key.offset = hash_extent_data_ref(root_objectid,
 571                                                   owner, offset);
 572                 size = sizeof(struct btrfs_extent_data_ref);
 573         }
 574
 575         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
 576         if (ret && ret != -EEXIST)
 577                 goto fail;
 578
 579         leaf = path->nodes[0];
 580         if (parent) {
 581                 struct btrfs_shared_data_ref *ref;
 582                 ref = btrfs_item_ptr(leaf, path->slots[0],
 583                                      struct btrfs_shared_data_ref);
 584                 if (ret == 0) {
 585                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
 586                 } else {
 587                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
 588                         num_refs += refs_to_add;
 589                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
 590                 }
 591         } else {
 592                 struct btrfs_extent_data_ref *ref;
 593                 while (ret == -EEXIST) {
 594                         ref = btrfs_item_ptr(leaf, path->slots[0],
 595                                              struct btrfs_extent_data_ref);
 596                         if (match_extent_data_ref(leaf, ref, root_objectid,
 597                                                   owner, offset))
 598                                 break;
 599                         btrfs_release_path(path);
 600                         key.offset++;
 601                         ret = btrfs_insert_empty_item(trans, root, path, &key,
 602                                                       size);
 603                         if (ret && ret != -EEXIST)
 604                                 goto fail;
 605
 606                         leaf = path->nodes[0];
 607                 }
 608                 ref = btrfs_item_ptr(leaf, path->slots[0],
 609                                      struct btrfs_extent_data_ref);
 610                 if (ret == 0) {
 611                         btrfs_set_extent_data_ref_root(leaf, ref,
 612                                                        root_objectid);
 613                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
 614                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
 615                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
 616                 } else {
 617                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
 618                         num_refs += refs_to_add;
 619                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
 620                 }
 621         }
 622         btrfs_mark_buffer_dirty(leaf);
 623         ret = 0;
 624 fail:
 625         btrfs_release_path(path);
 626         return ret;
 627 }
 628
 629 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
 630                                            struct btrfs_path *path,
 631                                            int refs_to_drop, int *last_ref)
 632 {
 633         struct btrfs_key key;
 634         struct btrfs_extent_data_ref *ref1 = NULL;
 635         struct btrfs_shared_data_ref *ref2 = NULL;
 636         struct extent_buffer *leaf;
 637         u32 num_refs = 0;
 638         int ret = 0;
 639
 640         leaf = path->nodes[0];
 641         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 642
 643         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 644                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 645                                       struct btrfs_extent_data_ref);
 646                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 647         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 648                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 649                                       struct btrfs_shared_data_ref);
 650                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 651         } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
 652                 btrfs_print_v0_err(trans->fs_info);
 653                 btrfs_abort_transaction(trans, -EINVAL);
 654                 return -EINVAL;
 655         } else {
 656                 BUG();
 657         }
 658
 659         BUG_ON(num_refs < refs_to_drop);
 660         num_refs -= refs_to_drop;
 661
 662         if (num_refs == 0) {
 663                 ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
 664                 *last_ref = 1;
 665         } else {
 666                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
 667                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
 668                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
 669                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
 670                 btrfs_mark_buffer_dirty(leaf);
 671         }
 672         return ret;
 673 }
 674
 675 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
 676                                           struct btrfs_extent_inline_ref *iref)
 677 {
 678         struct btrfs_key key;
 679         struct extent_buffer *leaf;
 680         struct btrfs_extent_data_ref *ref1;
 681         struct btrfs_shared_data_ref *ref2;
 682         u32 num_refs = 0;
 683         int type;
 684
 685         leaf = path->nodes[0];
 686         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 687
 688         BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
 689         if (iref) {
 690                 /*
 691                  * If type is invalid, we should have bailed out earlier than
 692                  * this call.
 693                  */
 694                 type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
 695                 ASSERT(type != BTRFS_REF_TYPE_INVALID);
 696                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
 697                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
 698                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 699                 } else {
 700                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
 701                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 702                 }
 703         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 704                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 705                                       struct btrfs_extent_data_ref);
 706                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 707         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 708                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 709                                       struct btrfs_shared_data_ref);
 710                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 711         } else {
 712                 WARN_ON(1);
 713         }
 714         return num_refs;
 715 }
 716
 717 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
 718                                           struct btrfs_path *path,
 719                                           u64 bytenr, u64 parent,
 720                                           u64 root_objectid)
 721 {
 722         struct btrfs_root *root = trans->fs_info->extent_root;
 723         struct btrfs_key key;
 724         int ret;
 725
 726         key.objectid = bytenr;
 727         if (parent) {
 728                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 729                 key.offset = parent;
 730         } else {
 731                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 732                 key.offset = root_objectid;
 733         }
 734
 735         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 736         if (ret > 0)
 737                 ret = -ENOENT;
 738         return ret;
 739 }
 740
 741 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
 742                                           struct btrfs_path *path,
 743                                           u64 bytenr, u64 parent,
 744                                           u64 root_objectid)
 745 {
 746         struct btrfs_key key;
 747         int ret;
 748
 749         key.objectid = bytenr;
 750         if (parent) {
 751                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 752                 key.offset = parent;
 753         } else {
 754                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 755                 key.offset = root_objectid;
 756         }
 757
 758         ret = btrfs_insert_empty_item(trans, trans->fs_info->extent_root,
 759                                       path, &key, 0);
 760         btrfs_release_path(path);
 761         return ret;
 762 }
 763
 764 static inline int extent_ref_type(u64 parent, u64 owner)
 765 {
 766         int type;
 767         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 768                 if (parent > 0)
 769                         type = BTRFS_SHARED_BLOCK_REF_KEY;
 770                 else
 771                         type = BTRFS_TREE_BLOCK_REF_KEY;
 772         } else {
 773                 if (parent > 0)
 774                         type = BTRFS_SHARED_DATA_REF_KEY;
 775                 else
 776                         type = BTRFS_EXTENT_DATA_REF_KEY;
 777         }
 778         return type;
 779 }
 780
 781 static int find_next_key(struct btrfs_path *path, int level,
 782                          struct btrfs_key *key)
 783
 784 {
 785         for (; level < BTRFS_MAX_LEVEL; level++) {
 786                 if (!path->nodes[level])
 787                         break;
 788                 if (path->slots[level] + 1 >=
 789                     btrfs_header_nritems(path->nodes[level]))
 790                         continue;
 791                 if (level == 0)
 792                         btrfs_item_key_to_cpu(path->nodes[level], key,
 793                                               path->slots[level] + 1);
 794                 else
 795                         btrfs_node_key_to_cpu(path->nodes[level], key,
 796                                               path->slots[level] + 1);
 797                 return 0;
 798         }
 799         return 1;
 800 }
 801
 802 /*
 803  * look for inline back ref. if back ref is found, *ref_ret is set
 804  * to the address of inline back ref, and 0 is returned.
 805  *
 806  * if back ref isn't found, *ref_ret is set to the address where it
 807  * should be inserted, and -ENOENT is returned.
 808  *
 809  * if insert is true and there are too many inline back refs, the path
 810  * points to the extent item, and -EAGAIN is returned.
 811  *
 812  * NOTE: inline back refs are ordered in the same way that back ref
 813  *       items in the tree are ordered.
 814  */
 815 static noinline_for_stack
 816 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
 817                                  struct btrfs_path *path,
 818                                  struct btrfs_extent_inline_ref **ref_ret,
 819                                  u64 bytenr, u64 num_bytes,
 820                                  u64 parent, u64 root_objectid,
 821                                  u64 owner, u64 offset, int insert)
 822 {
 823         struct btrfs_fs_info *fs_info = trans->fs_info;
 824         struct btrfs_root *root = fs_info->extent_root;
 825         struct btrfs_key key;
 826         struct extent_buffer *leaf;
 827         struct btrfs_extent_item *ei;
 828         struct btrfs_extent_inline_ref *iref;
 829         u64 flags;
 830         u64 item_size;
 831         unsigned long ptr;
 832         unsigned long end;
 833         int extra_size;
 834         int type;
 835         int want;
 836         int ret;
 837         int err = 0;
 838         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
 839         int needed;
 840
 841         key.objectid = bytenr;
 842         key.type = BTRFS_EXTENT_ITEM_KEY;
 843         key.offset = num_bytes;
 844
 845         want = extent_ref_type(parent, owner);
 846         if (insert) {
 847                 extra_size = btrfs_extent_inline_ref_size(want);
 848                 path->keep_locks = 1;
 849         } else
 850                 extra_size = -1;
 851
 852         /*
 853          * Owner is our level, so we can just add one to get the level for the
 854          * block we are interested in.
 855          */
 856         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
 857                 key.type = BTRFS_METADATA_ITEM_KEY;
 858                 key.offset = owner;
 859         }
 860
 861 again:
 862         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
 863         if (ret < 0) {
 864                 err = ret;
 865                 goto out;
 866         }
 867
 868         /*
 869          * We may be a newly converted file system which still has the old fat
 870          * extent entries for metadata, so try and see if we have one of those.
 871          */
 872         if (ret > 0 && skinny_metadata) {
 873                 skinny_metadata = false;
 874                 if (path->slots[0]) {
 875                         path->slots[0]--;
 876                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 877                                               path->slots[0]);
 878                         if (key.objectid == bytenr &&
 879                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 880                             key.offset == num_bytes)
 881                                 ret = 0;
 882                 }
 883                 if (ret) {
 884                         key.objectid = bytenr;
 885                         key.type = BTRFS_EXTENT_ITEM_KEY;
 886                         key.offset = num_bytes;
 887                         btrfs_release_path(path);
 888                         goto again;
 889                 }
 890         }
 891
 892         if (ret && !insert) {
 893                 err = -ENOENT;
 894                 goto out;
 895         } else if (WARN_ON(ret)) {
 896                 err = -EIO;
 897                 goto out;
 898         }
 899
 900         leaf = path->nodes[0];
 901         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 902         if (unlikely(item_size < sizeof(*ei))) {
 903                 err = -EINVAL;
 904                 btrfs_print_v0_err(fs_info);
 905                 btrfs_abort_transaction(trans, err);
 906                 goto out;
 907         }
 908
 909         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 910         flags = btrfs_extent_flags(leaf, ei);
 911
 912         ptr = (unsigned long)(ei + 1);
 913         end = (unsigned long)ei + item_size;
 914
 915         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
 916                 ptr += sizeof(struct btrfs_tree_block_info);
 917                 BUG_ON(ptr > end);
 918         }
 919
 920         if (owner >= BTRFS_FIRST_FREE_OBJECTID)
 921                 needed = BTRFS_REF_TYPE_DATA;
 922         else
 923                 needed = BTRFS_REF_TYPE_BLOCK;
 924
 925         err = -ENOENT;
 926         while (1) {
 927                 if (ptr >= end) {
 928                         WARN_ON(ptr > end);
 929                         break;
 930                 }
 931                 iref = (struct btrfs_extent_inline_ref *)ptr;
 932                 type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
 933                 if (type == BTRFS_REF_TYPE_INVALID) {
 934                         err = -EUCLEAN;
 935                         goto out;
 936                 }
 937
 938                 if (want < type)
 939                         break;
 940                 if (want > type) {
 941                         ptr += btrfs_extent_inline_ref_size(type);
 942                         continue;
 943                 }
 944
 945                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
 946                         struct btrfs_extent_data_ref *dref;
 947                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
 948                         if (match_extent_data_ref(leaf, dref, root_objectid,
 949                                                   owner, offset)) {
 950                                 err = 0;
 951                                 break;
 952                         }
 953                         if (hash_extent_data_ref_item(leaf, dref) <
 954                             hash_extent_data_ref(root_objectid, owner, offset))
 955                                 break;
 956                 } else {
 957                         u64 ref_offset;
 958                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
 959                         if (parent > 0) {
 960                                 if (parent == ref_offset) {
 961                                         err = 0;
 962                                         break;
 963                                 }
 964                                 if (ref_offset < parent)
 965                                         break;
 966                         } else {
 967                                 if (root_objectid == ref_offset) {
 968                                         err = 0;
 969                                         break;
 970                                 }
 971                                 if (ref_offset < root_objectid)
 972                                         break;
 973                         }
 974                 }
 975                 ptr += btrfs_extent_inline_ref_size(type);
 976         }
 977         if (err == -ENOENT && insert) {
 978                 if (item_size + extra_size >=
 979                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
 980                         err = -EAGAIN;
 981                         goto out;
 982                 }
 983                 /*
 984                  * To add new inline back ref, we have to make sure
 985                  * there is no corresponding back ref item.
 986                  * For simplicity, we just do not add new inline back
 987                  * ref if there is any kind of item for this block
 988                  */
 989                 if (find_next_key(path, 0, &key) == 0 &&
 990                     key.objectid == bytenr &&
 991                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
 992                         err = -EAGAIN;
 993                         goto out;
 994                 }
 995         }
 996         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
 997 out:
 998         if (insert) {
 999                 path->keep_locks = 0;
1000                 btrfs_unlock_up_safe(path, 1);
1001         }
1002         return err;
1003 }
1004
1005 /*
1006  * helper to add new inline back ref
1007  */
1008 static noinline_for_stack
1009 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1010                                  struct btrfs_path *path,
1011                                  struct btrfs_extent_inline_ref *iref,
1012                                  u64 parent, u64 root_objectid,
1013                                  u64 owner, u64 offset, int refs_to_add,
1014                                  struct btrfs_delayed_extent_op *extent_op)
1015 {
1016         struct extent_buffer *leaf;
1017         struct btrfs_extent_item *ei;
1018         unsigned long ptr;
1019         unsigned long end;
1020         unsigned long item_offset;
1021         u64 refs;
1022         int size;
1023         int type;
1024
1025         leaf = path->nodes[0];
1026         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1027         item_offset = (unsigned long)iref - (unsigned long)ei;
1028
1029         type = extent_ref_type(parent, owner);
1030         size = btrfs_extent_inline_ref_size(type);
1031
1032         btrfs_extend_item(path, size);
1033
1034         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1035         refs = btrfs_extent_refs(leaf, ei);
1036         refs += refs_to_add;
1037         btrfs_set_extent_refs(leaf, ei, refs);
1038         if (extent_op)
1039                 __run_delayed_extent_op(extent_op, leaf, ei);
1040
1041         ptr = (unsigned long)ei + item_offset;
1042         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1043         if (ptr < end - size)
1044                 memmove_extent_buffer(leaf, ptr + size, ptr,
1045                                       end - size - ptr);
1046
1047         iref = (struct btrfs_extent_inline_ref *)ptr;
1048         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1049         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1050                 struct btrfs_extent_data_ref *dref;
1051                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1052                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1053                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1054                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1055                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1056         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1057                 struct btrfs_shared_data_ref *sref;
1058                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1059                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1060                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1061         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1062                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1063         } else {
1064                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1065         }
1066         btrfs_mark_buffer_dirty(leaf);
1067 }
1068
1069 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1070                                  struct btrfs_path *path,
1071                                  struct btrfs_extent_inline_ref **ref_ret,
1072                                  u64 bytenr, u64 num_bytes, u64 parent,
1073                                  u64 root_objectid, u64 owner, u64 offset)
1074 {
1075         int ret;
1076
1077         ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
1078                                            num_bytes, parent, root_objectid,
1079                                            owner, offset, 0);
1080         if (ret != -ENOENT)
1081                 return ret;
1082
1083         btrfs_release_path(path);
1084         *ref_ret = NULL;
1085
1086         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1087                 ret = lookup_tree_block_ref(trans, path, bytenr, parent,
1088                                             root_objectid);
1089         } else {
1090                 ret = lookup_extent_data_ref(trans, path, bytenr, parent,
1091                                              root_objectid, owner, offset);
1092         }
1093         return ret;
1094 }
1095
1096 /*
1097  * helper to update/remove inline back ref
1098  */
1099 static noinline_for_stack
1100 void update_inline_extent_backref(struct btrfs_path *path,
1101                                   struct btrfs_extent_inline_ref *iref,
1102                                   int refs_to_mod,
1103                                   struct btrfs_delayed_extent_op *extent_op,
1104                                   int *last_ref)
1105 {
1106         struct extent_buffer *leaf = path->nodes[0];
1107         struct btrfs_extent_item *ei;
1108         struct btrfs_extent_data_ref *dref = NULL;
1109         struct btrfs_shared_data_ref *sref = NULL;
1110         unsigned long ptr;
1111         unsigned long end;
1112         u32 item_size;
1113         int size;
1114         int type;
1115         u64 refs;
1116
1117         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1118         refs = btrfs_extent_refs(leaf, ei);
1119         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1120         refs += refs_to_mod;
1121         btrfs_set_extent_refs(leaf, ei, refs);
1122         if (extent_op)
1123                 __run_delayed_extent_op(extent_op, leaf, ei);
1124
1125         /*
1126          * If type is invalid, we should have bailed out after
1127          * lookup_inline_extent_backref().
1128          */
1129         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1130         ASSERT(type != BTRFS_REF_TYPE_INVALID);
1131
1132         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1133                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1134                 refs = btrfs_extent_data_ref_count(leaf, dref);
1135         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1136                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1137                 refs = btrfs_shared_data_ref_count(leaf, sref);
1138         } else {
1139                 refs = 1;
1140                 BUG_ON(refs_to_mod != -1);
1141         }
1142
1143         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1144         refs += refs_to_mod;
1145
1146         if (refs > 0) {
1147                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1148                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1149                 else
1150                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1151         } else {
1152                 *last_ref = 1;
1153                 size =  btrfs_extent_inline_ref_size(type);
1154                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1155                 ptr = (unsigned long)iref;
1156                 end = (unsigned long)ei + item_size;
1157                 if (ptr + size < end)
1158                         memmove_extent_buffer(leaf, ptr, ptr + size,
1159                                               end - ptr - size);
1160                 item_size -= size;
1161                 btrfs_truncate_item(path, item_size, 1);
1162         }
1163         btrfs_mark_buffer_dirty(leaf);
1164 }
1165
1166 static noinline_for_stack
1167 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1168                                  struct btrfs_path *path,
1169                                  u64 bytenr, u64 num_bytes, u64 parent,
1170                                  u64 root_objectid, u64 owner,
1171                                  u64 offset, int refs_to_add,
1172                                  struct btrfs_delayed_extent_op *extent_op)
1173 {
1174         struct btrfs_extent_inline_ref *iref;
1175         int ret;
1176
1177         ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
1178                                            num_bytes, parent, root_objectid,
1179                                            owner, offset, 1);
1180         if (ret == 0) {
1181                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1182                 update_inline_extent_backref(path, iref, refs_to_add,
1183                                              extent_op, NULL);
1184         } else if (ret == -ENOENT) {
1185                 setup_inline_extent_backref(trans->fs_info, path, iref, parent,
1186                                             root_objectid, owner, offset,
1187                                             refs_to_add, extent_op);
1188                 ret = 0;
1189         }
1190         return ret;
1191 }
1192
1193 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1194                                  struct btrfs_path *path,
1195                                  struct btrfs_extent_inline_ref *iref,
1196                                  int refs_to_drop, int is_data, int *last_ref)
1197 {
1198         int ret = 0;
1199
1200         BUG_ON(!is_data && refs_to_drop != 1);
1201         if (iref) {
1202                 update_inline_extent_backref(path, iref, -refs_to_drop, NULL,
1203                                              last_ref);
1204         } else if (is_data) {
1205                 ret = remove_extent_data_ref(trans, path, refs_to_drop,
1206                                              last_ref);
1207         } else {
1208                 *last_ref = 1;
1209                 ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
1210         }
1211         return ret;
1212 }
1213
1214 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1215                                u64 *discarded_bytes)
1216 {
1217         int j, ret = 0;
1218         u64 bytes_left, end;
1219         u64 aligned_start = ALIGN(start, 1 << 9);
1220
1221         if (WARN_ON(start != aligned_start)) {
1222                 len -= aligned_start - start;
1223                 len = round_down(len, 1 << 9);
1224                 start = aligned_start;
1225         }
1226
1227         *discarded_bytes = 0;
1228
1229         if (!len)
1230                 return 0;
1231
1232         end = start + len;
1233         bytes_left = len;
1234
1235         /* Skip any superblocks on this device. */
1236         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1237                 u64 sb_start = btrfs_sb_offset(j);
1238                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1239                 u64 size = sb_start - start;
1240
1241                 if (!in_range(sb_start, start, bytes_left) &&
1242                     !in_range(sb_end, start, bytes_left) &&
1243                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1244                         continue;
1245
1246                 /*
1247                  * Superblock spans beginning of range.  Adjust start and
1248                  * try again.
1249                  */
1250                 if (sb_start <= start) {
1251                         start += sb_end - start;
1252                         if (start > end) {
1253                                 bytes_left = 0;
1254                                 break;
1255                         }
1256                         bytes_left = end - start;
1257                         continue;
1258                 }
1259
1260                 if (size) {
1261                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
1262                                                    GFP_NOFS, 0);
1263                         if (!ret)
1264                                 *discarded_bytes += size;
1265                         else if (ret != -EOPNOTSUPP)
1266                                 return ret;
1267                 }
1268
1269                 start = sb_end;
1270                 if (start > end) {
1271                         bytes_left = 0;
1272                         break;
1273                 }
1274                 bytes_left = end - start;
1275         }
1276
1277         if (bytes_left) {
1278                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
1279                                            GFP_NOFS, 0);
1280                 if (!ret)
1281                         *discarded_bytes += bytes_left;
1282         }
1283         return ret;
1284 }
1285
1286 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
1287                          u64 num_bytes, u64 *actual_bytes)
1288 {
1289         int ret = 0;
1290         u64 discarded_bytes = 0;
1291         u64 end = bytenr + num_bytes;
1292         u64 cur = bytenr;
1293         struct btrfs_bio *bbio = NULL;
1294
1295
1296         /*
1297          * Avoid races with device replace and make sure our bbio has devices
1298          * associated to its stripes that don't go away while we are discarding.
1299          */
1300         btrfs_bio_counter_inc_blocked(fs_info);
1301         while (cur < end) {
1302                 struct btrfs_bio_stripe *stripe;
1303                 int i;
1304
1305                 num_bytes = end - cur;
1306                 /* Tell the block device(s) that the sectors can be discarded */
1307                 ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, cur,
1308                                       &num_bytes, &bbio, 0);
1309                 /*
1310                  * Error can be -ENOMEM, -ENOENT (no such chunk mapping) or
1311                  * -EOPNOTSUPP. For any such error, @num_bytes is not updated,
1312                  * thus we can't continue anyway.
1313                  */
1314                 if (ret < 0)
1315                         goto out;
1316
1317                 stripe = bbio->stripes;
1318                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1319                         u64 bytes;
1320                         struct request_queue *req_q;
1321
1322                         if (!stripe->dev->bdev) {
1323                                 ASSERT(btrfs_test_opt(fs_info, DEGRADED));
1324                                 continue;
1325                         }
1326                         req_q = bdev_get_queue(stripe->dev->bdev);
1327                         if (!blk_queue_discard(req_q))
1328                                 continue;
1329
1330                         ret = btrfs_issue_discard(stripe->dev->bdev,
1331                                                   stripe->physical,
1332                                                   stripe->length,
1333                                                   &bytes);
1334                         if (!ret) {
1335                                 discarded_bytes += bytes;
1336                         } else if (ret != -EOPNOTSUPP) {
1337                                 /*
1338                                  * Logic errors or -ENOMEM, or -EIO, but
1339                                  * unlikely to happen.
1340                                  *
1341                                  * And since there are two loops, explicitly
1342                                  * go to out to avoid confusion.
1343                                  */
1344                                 btrfs_put_bbio(bbio);
1345                                 goto out;
1346                         }
1347
1348                         /*
1349                          * Just in case we get back EOPNOTSUPP for some reason,
1350                          * just ignore the return value so we don't screw up
1351                          * people calling discard_extent.
1352                          */
1353                         ret = 0;
1354                 }
1355                 btrfs_put_bbio(bbio);
1356                 cur += num_bytes;
1357         }
1358 out:
1359         btrfs_bio_counter_dec(fs_info);
1360
1361         if (actual_bytes)
1362                 *actual_bytes = discarded_bytes;
1363
1364
1365         if (ret == -EOPNOTSUPP)
1366                 ret = 0;
1367         return ret;
1368 }
1369
1370 /* Can return -ENOMEM */
1371 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1372                          struct btrfs_ref *generic_ref)
1373 {
1374         struct btrfs_fs_info *fs_info = trans->fs_info;
1375         int old_ref_mod, new_ref_mod;
1376         int ret;
1377
1378         ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&
1379                generic_ref->action);
1380         BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&
1381                generic_ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID);
1382
1383         if (generic_ref->type == BTRFS_REF_METADATA)
1384                 ret = btrfs_add_delayed_tree_ref(trans, generic_ref,
1385                                 NULL, &old_ref_mod, &new_ref_mod);
1386         else
1387                 ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0,
1388                                                  &old_ref_mod, &new_ref_mod);
1389
1390         btrfs_ref_tree_mod(fs_info, generic_ref);
1391
1392         if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
1393                 sub_pinned_bytes(fs_info, generic_ref);
1394
1395         return ret;
1396 }
1397
1398 /*
1399  * __btrfs_inc_extent_ref - insert backreference for a given extent
1400  *
1401  * @trans:          Handle of transaction
1402  *
1403  * @node:           The delayed ref node used to get the bytenr/length for
1404  *                  extent whose references are incremented.
1405  *
1406  * @parent:         If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
1407  *                  BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
1408  *                  bytenr of the parent block. Since new extents are always
1409  *                  created with indirect references, this will only be the case
1410  *                  when relocating a shared extent. In that case, root_objectid
1411  *                  will be BTRFS_TREE_RELOC_OBJECTID. Otheriwse, parent must
1412  *                  be 0
1413  *
1414  * @root_objectid:  The id of the root where this modification has originated,
1415  *                  this can be either one of the well-known metadata trees or
1416  *                  the subvolume id which references this extent.
1417  *
1418  * @owner:          For data extents it is the inode number of the owning file.
1419  *                  For metadata extents this parameter holds the level in the
1420  *                  tree of the extent.
1421  *
1422  * @offset:         For metadata extents the offset is ignored and is currently
1423  *                  always passed as 0. For data extents it is the fileoffset
1424  *                  this extent belongs to.
1425  *
1426  * @refs_to_add     Number of references to add
1427  *
1428  * @extent_op       Pointer to a structure, holding information necessary when
1429  *                  updating a tree block's flags
1430  *
1431  */
1432 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1433                                   struct btrfs_delayed_ref_node *node,
1434                                   u64 parent, u64 root_objectid,
1435                                   u64 owner, u64 offset, int refs_to_add,
1436                                   struct btrfs_delayed_extent_op *extent_op)
1437 {
1438         struct btrfs_path *path;
1439         struct extent_buffer *leaf;
1440         struct btrfs_extent_item *item;
1441         struct btrfs_key key;
1442         u64 bytenr = node->bytenr;
1443         u64 num_bytes = node->num_bytes;
1444         u64 refs;
1445         int ret;
1446
1447         path = btrfs_alloc_path();
1448         if (!path)
1449                 return -ENOMEM;
1450
1451         path->leave_spinning = 1;
1452         /* this will setup the path even if it fails to insert the back ref */
1453         ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
1454                                            parent, root_objectid, owner,
1455                                            offset, refs_to_add, extent_op);
1456         if ((ret < 0 && ret != -EAGAIN) || !ret)
1457                 goto out;
1458
1459         /*
1460          * Ok we had -EAGAIN which means we didn't have space to insert and
1461          * inline extent ref, so just update the reference count and add a
1462          * normal backref.
1463          */
1464         leaf = path->nodes[0];
1465         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1466         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1467         refs = btrfs_extent_refs(leaf, item);
1468         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1469         if (extent_op)
1470                 __run_delayed_extent_op(extent_op, leaf, item);
1471
1472         btrfs_mark_buffer_dirty(leaf);
1473         btrfs_release_path(path);
1474
1475         path->leave_spinning = 1;
1476         /* now insert the actual backref */
1477         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1478                 BUG_ON(refs_to_add != 1);
1479                 ret = insert_tree_block_ref(trans, path, bytenr, parent,
1480                                             root_objectid);
1481         } else {
1482                 ret = insert_extent_data_ref(trans, path, bytenr, parent,
1483                                              root_objectid, owner, offset,
1484                                              refs_to_add);
1485         }
1486         if (ret)
1487                 btrfs_abort_transaction(trans, ret);
1488 out:
1489         btrfs_free_path(path);
1490         return ret;
1491 }
1492
1493 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1494                                 struct btrfs_delayed_ref_node *node,
1495                                 struct btrfs_delayed_extent_op *extent_op,
1496                                 int insert_reserved)
1497 {
1498         int ret = 0;
1499         struct btrfs_delayed_data_ref *ref;
1500         struct btrfs_key ins;
1501         u64 parent = 0;
1502         u64 ref_root = 0;
1503         u64 flags = 0;
1504
1505         ins.objectid = node->bytenr;
1506         ins.offset = node->num_bytes;
1507         ins.type = BTRFS_EXTENT_ITEM_KEY;
1508
1509         ref = btrfs_delayed_node_to_data_ref(node);
1510         trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
1511
1512         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1513                 parent = ref->parent;
1514         ref_root = ref->root;
1515
1516         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1517                 if (extent_op)
1518                         flags |= extent_op->flags_to_set;
1519                 ret = alloc_reserved_file_extent(trans, parent, ref_root,
1520                                                  flags, ref->objectid,
1521                                                  ref->offset, &ins,
1522                                                  node->ref_mod);
1523         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1524                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
1525                                              ref->objectid, ref->offset,
1526                                              node->ref_mod, extent_op);
1527         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1528                 ret = __btrfs_free_extent(trans, node, parent,
1529                                           ref_root, ref->objectid,
1530                                           ref->offset, node->ref_mod,
1531                                           extent_op);
1532         } else {
1533                 BUG();
1534         }
1535         return ret;
1536 }
1537
1538 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1539                                     struct extent_buffer *leaf,
1540                                     struct btrfs_extent_item *ei)
1541 {
1542         u64 flags = btrfs_extent_flags(leaf, ei);
1543         if (extent_op->update_flags) {
1544                 flags |= extent_op->flags_to_set;
1545                 btrfs_set_extent_flags(leaf, ei, flags);
1546         }
1547
1548         if (extent_op->update_key) {
1549                 struct btrfs_tree_block_info *bi;
1550                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1551                 bi = (struct btrfs_tree_block_info *)(ei + 1);
1552                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1553         }
1554 }
1555
1556 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1557                                  struct btrfs_delayed_ref_head *head,
1558                                  struct btrfs_delayed_extent_op *extent_op)
1559 {
1560         struct btrfs_fs_info *fs_info = trans->fs_info;
1561         struct btrfs_key key;
1562         struct btrfs_path *path;
1563         struct btrfs_extent_item *ei;
1564         struct extent_buffer *leaf;
1565         u32 item_size;
1566         int ret;
1567         int err = 0;
1568         int metadata = !extent_op->is_data;
1569
1570         if (TRANS_ABORTED(trans))
1571                 return 0;
1572
1573         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1574                 metadata = 0;
1575
1576         path = btrfs_alloc_path();
1577         if (!path)
1578                 return -ENOMEM;
1579
1580         key.objectid = head->bytenr;
1581
1582         if (metadata) {
1583                 key.type = BTRFS_METADATA_ITEM_KEY;
1584                 key.offset = extent_op->level;
1585         } else {
1586                 key.type = BTRFS_EXTENT_ITEM_KEY;
1587                 key.offset = head->num_bytes;
1588         }
1589
1590 again:
1591         path->leave_spinning = 1;
1592         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
1593         if (ret < 0) {
1594                 err = ret;
1595                 goto out;
1596         }
1597         if (ret > 0) {
1598                 if (metadata) {
1599                         if (path->slots[0] > 0) {
1600                                 path->slots[0]--;
1601                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
1602                                                       path->slots[0]);
1603                                 if (key.objectid == head->bytenr &&
1604                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
1605                                     key.offset == head->num_bytes)
1606                                         ret = 0;
1607                         }
1608                         if (ret > 0) {
1609                                 btrfs_release_path(path);
1610                                 metadata = 0;
1611
1612                                 key.objectid = head->bytenr;
1613                                 key.offset = head->num_bytes;
1614                                 key.type = BTRFS_EXTENT_ITEM_KEY;
1615                                 goto again;
1616                         }
1617                 } else {
1618                         err = -EIO;
1619                         goto out;
1620                 }
1621         }
1622
1623         leaf = path->nodes[0];
1624         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1625
1626         if (unlikely(item_size < sizeof(*ei))) {
1627                 err = -EINVAL;
1628                 btrfs_print_v0_err(fs_info);
1629                 btrfs_abort_transaction(trans, err);
1630                 goto out;
1631         }
1632
1633         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1634         __run_delayed_extent_op(extent_op, leaf, ei);
1635
1636         btrfs_mark_buffer_dirty(leaf);
1637 out:
1638         btrfs_free_path(path);
1639         return err;
1640 }
1641
1642 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
1643                                 struct btrfs_delayed_ref_node *node,
1644                                 struct btrfs_delayed_extent_op *extent_op,
1645                                 int insert_reserved)
1646 {
1647         int ret = 0;
1648         struct btrfs_delayed_tree_ref *ref;
1649         u64 parent = 0;
1650         u64 ref_root = 0;
1651
1652         ref = btrfs_delayed_node_to_tree_ref(node);
1653         trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
1654
1655         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1656                 parent = ref->parent;
1657         ref_root = ref->root;
1658
1659         if (node->ref_mod != 1) {
1660                 btrfs_err(trans->fs_info,
1661         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
1662                           node->bytenr, node->ref_mod, node->action, ref_root,
1663                           parent);
1664                 return -EIO;
1665         }
1666         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1667                 BUG_ON(!extent_op || !extent_op->update_flags);
1668                 ret = alloc_reserved_tree_block(trans, node, extent_op);
1669         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1670                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
1671                                              ref->level, 0, 1, extent_op);
1672         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1673                 ret = __btrfs_free_extent(trans, node, parent, ref_root,
1674                                           ref->level, 0, 1, extent_op);
1675         } else {
1676                 BUG();
1677         }
1678         return ret;
1679 }
1680
1681 /* helper function to actually process a single delayed ref entry */
1682 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
1683                                struct btrfs_delayed_ref_node *node,
1684                                struct btrfs_delayed_extent_op *extent_op,
1685                                int insert_reserved)
1686 {
1687         int ret = 0;
1688
1689         if (TRANS_ABORTED(trans)) {
1690                 if (insert_reserved)
1691                         btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);
1692                 return 0;
1693         }
1694
1695         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
1696             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1697                 ret = run_delayed_tree_ref(trans, node, extent_op,
1698                                            insert_reserved);
1699         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
1700                  node->type == BTRFS_SHARED_DATA_REF_KEY)
1701                 ret = run_delayed_data_ref(trans, node, extent_op,
1702                                            insert_reserved);
1703         else
1704                 BUG();
1705         if (ret && insert_reserved)
1706                 btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);
1707         return ret;
1708 }
1709
1710 static inline struct btrfs_delayed_ref_node *
1711 select_delayed_ref(struct btrfs_delayed_ref_head *head)
1712 {
1713         struct btrfs_delayed_ref_node *ref;
1714
1715         if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
1716                 return NULL;
1717
1718         /*
1719          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
1720          * This is to prevent a ref count from going down to zero, which deletes
1721          * the extent item from the extent tree, when there still are references
1722          * to add, which would fail because they would not find the extent item.
1723          */
1724         if (!list_empty(&head->ref_add_list))
1725                 return list_first_entry(&head->ref_add_list,
1726                                 struct btrfs_delayed_ref_node, add_list);
1727
1728         ref = rb_entry(rb_first_cached(&head->ref_tree),
1729                        struct btrfs_delayed_ref_node, ref_node);
1730         ASSERT(list_empty(&ref->add_list));
1731         return ref;
1732 }
1733
1734 static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
1735                                       struct btrfs_delayed_ref_head *head)
1736 {
1737         spin_lock(&delayed_refs->lock);
1738         head->processing = 0;
1739         delayed_refs->num_heads_ready++;
1740         spin_unlock(&delayed_refs->lock);
1741         btrfs_delayed_ref_unlock(head);
1742 }
1743
1744 static struct btrfs_delayed_extent_op *cleanup_extent_op(
1745                                 struct btrfs_delayed_ref_head *head)
1746 {
1747         struct btrfs_delayed_extent_op *extent_op = head->extent_op;
1748
1749         if (!extent_op)
1750                 return NULL;
1751
1752         if (head->must_insert_reserved) {
1753                 head->extent_op = NULL;
1754                 btrfs_free_delayed_extent_op(extent_op);
1755                 return NULL;
1756         }
1757         return extent_op;
1758 }
1759
1760 static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
1761                                      struct btrfs_delayed_ref_head *head)
1762 {
1763         struct btrfs_delayed_extent_op *extent_op;
1764         int ret;
1765
1766         extent_op = cleanup_extent_op(head);
1767         if (!extent_op)
1768                 return 0;
1769         head->extent_op = NULL;
1770         spin_unlock(&head->lock);
1771         ret = run_delayed_extent_op(trans, head, extent_op);
1772         btrfs_free_delayed_extent_op(extent_op);
1773         return ret ? ret : 1;
1774 }
1775
1776 void btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
1777                                   struct btrfs_delayed_ref_root *delayed_refs,
1778                                   struct btrfs_delayed_ref_head *head)
1779 {
1780         int nr_items = 1;       /* Dropping this ref head update. */
1781
1782         if (head->total_ref_mod < 0) {
1783                 struct btrfs_space_info *space_info;
1784                 u64 flags;
1785
1786                 if (head->is_data)
1787                         flags = BTRFS_BLOCK_GROUP_DATA;
1788                 else if (head->is_system)
1789                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
1790                 else
1791                         flags = BTRFS_BLOCK_GROUP_METADATA;
1792                 space_info = btrfs_find_space_info(fs_info, flags);
1793                 ASSERT(space_info);
1794                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
1795                                    -head->num_bytes,
1796                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
1797
1798                 /*
1799                  * We had csum deletions accounted for in our delayed refs rsv,
1800                  * we need to drop the csum leaves for this update from our
1801                  * delayed_refs_rsv.
1802                  */
1803                 if (head->is_data) {
1804                         spin_lock(&delayed_refs->lock);
1805                         delayed_refs->pending_csums -= head->num_bytes;
1806                         spin_unlock(&delayed_refs->lock);
1807                         nr_items += btrfs_csum_bytes_to_leaves(fs_info,
1808                                 head->num_bytes);
1809                 }
1810         }
1811
1812         btrfs_delayed_refs_rsv_release(fs_info, nr_items);
1813 }
1814
1815 static int cleanup_ref_head(struct btrfs_trans_handle *trans,
1816                             struct btrfs_delayed_ref_head *head)
1817 {
1818
1819         struct btrfs_fs_info *fs_info = trans->fs_info;
1820         struct btrfs_delayed_ref_root *delayed_refs;
1821         int ret;
1822
1823         delayed_refs = &trans->transaction->delayed_refs;
1824
1825         ret = run_and_cleanup_extent_op(trans, head);
1826         if (ret < 0) {
1827                 unselect_delayed_ref_head(delayed_refs, head);
1828                 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
1829                 return ret;
1830         } else if (ret) {
1831                 return ret;
1832         }
1833
1834         /*
1835          * Need to drop our head ref lock and re-acquire the delayed ref lock
1836          * and then re-check to make sure nobody got added.
1837          */
1838         spin_unlock(&head->lock);
1839         spin_lock(&delayed_refs->lock);
1840         spin_lock(&head->lock);
1841         if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
1842                 spin_unlock(&head->lock);
1843                 spin_unlock(&delayed_refs->lock);
1844                 return 1;
1845         }
1846         btrfs_delete_ref_head(delayed_refs, head);
1847         spin_unlock(&head->lock);
1848         spin_unlock(&delayed_refs->lock);
1849
1850         if (head->must_insert_reserved) {
1851                 btrfs_pin_extent(trans, head->bytenr, head->num_bytes, 1);
1852                 if (head->is_data) {
1853                         ret = btrfs_del_csums(trans, fs_info->csum_root,
1854                                               head->bytenr, head->num_bytes);
1855                 }
1856         }
1857
1858         btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
1859
1860         trace_run_delayed_ref_head(fs_info, head, 0);
1861         btrfs_delayed_ref_unlock(head);
1862         btrfs_put_delayed_ref_head(head);
1863         return 0;
1864 }
1865
1866 static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
1867                                         struct btrfs_trans_handle *trans)
1868 {
1869         struct btrfs_delayed_ref_root *delayed_refs =
1870                 &trans->transaction->delayed_refs;
1871         struct btrfs_delayed_ref_head *head = NULL;
1872         int ret;
1873
1874         spin_lock(&delayed_refs->lock);
1875         head = btrfs_select_ref_head(delayed_refs);
1876         if (!head) {
1877                 spin_unlock(&delayed_refs->lock);
1878                 return head;
1879         }
1880
1881         /*
1882          * Grab the lock that says we are going to process all the refs for
1883          * this head
1884          */
1885         ret = btrfs_delayed_ref_lock(delayed_refs, head);
1886         spin_unlock(&delayed_refs->lock);
1887
1888         /*
1889          * We may have dropped the spin lock to get the head mutex lock, and
1890          * that might have given someone else time to free the head.  If that's
1891          * true, it has been removed from our list and we can move on.
1892          */
1893         if (ret == -EAGAIN)
1894                 head = ERR_PTR(-EAGAIN);
1895
1896         return head;
1897 }
1898
1899 static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
1900                                     struct btrfs_delayed_ref_head *locked_ref,
1901                                     unsigned long *run_refs)
1902 {
1903         struct btrfs_fs_info *fs_info = trans->fs_info;
1904         struct btrfs_delayed_ref_root *delayed_refs;
1905         struct btrfs_delayed_extent_op *extent_op;
1906         struct btrfs_delayed_ref_node *ref;
1907         int must_insert_reserved = 0;
1908         int ret;
1909
1910         delayed_refs = &trans->transaction->delayed_refs;
1911
1912         lockdep_assert_held(&locked_ref->mutex);
1913         lockdep_assert_held(&locked_ref->lock);
1914
1915         while ((ref = select_delayed_ref(locked_ref))) {
1916                 if (ref->seq &&
1917                     btrfs_check_delayed_seq(fs_info, ref->seq)) {
1918                         spin_unlock(&locked_ref->lock);
1919                         unselect_delayed_ref_head(delayed_refs, locked_ref);
1920                         return -EAGAIN;
1921                 }
1922
1923                 (*run_refs)++;
1924                 ref->in_tree = 0;
1925                 rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
1926                 RB_CLEAR_NODE(&ref->ref_node);
1927                 if (!list_empty(&ref->add_list))
1928                         list_del(&ref->add_list);
1929                 /*
1930                  * When we play the delayed ref, also correct the ref_mod on
1931                  * head
1932                  */
1933                 switch (ref->action) {
1934                 case BTRFS_ADD_DELAYED_REF:
1935                 case BTRFS_ADD_DELAYED_EXTENT:
1936                         locked_ref->ref_mod -= ref->ref_mod;
1937                         break;
1938                 case BTRFS_DROP_DELAYED_REF:
1939                         locked_ref->ref_mod += ref->ref_mod;
1940                         break;
1941                 default:
1942                         WARN_ON(1);
1943                 }
1944                 atomic_dec(&delayed_refs->num_entries);
1945
1946                 /*
1947                  * Record the must_insert_reserved flag before we drop the
1948                  * spin lock.
1949                  */
1950                 must_insert_reserved = locked_ref->must_insert_reserved;
1951                 locked_ref->must_insert_reserved = 0;
1952
1953                 extent_op = locked_ref->extent_op;
1954                 locked_ref->extent_op = NULL;
1955                 spin_unlock(&locked_ref->lock);
1956
1957                 ret = run_one_delayed_ref(trans, ref, extent_op,
1958                                           must_insert_reserved);
1959
1960                 btrfs_free_delayed_extent_op(extent_op);
1961                 if (ret) {
1962                         unselect_delayed_ref_head(delayed_refs, locked_ref);
1963                         btrfs_put_delayed_ref(ref);
1964                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
1965                                     ret);
1966                         return ret;
1967                 }
1968
1969                 btrfs_put_delayed_ref(ref);
1970                 cond_resched();
1971
1972                 spin_lock(&locked_ref->lock);
1973                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
1974         }
1975
1976         return 0;
1977 }
1978
1979 /*
1980  * Returns 0 on success or if called with an already aborted transaction.
1981  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
1982  */
1983 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
1984                                              unsigned long nr)
1985 {
1986         struct btrfs_fs_info *fs_info = trans->fs_info;
1987         struct btrfs_delayed_ref_root *delayed_refs;
1988         struct btrfs_delayed_ref_head *locked_ref = NULL;
1989         ktime_t start = ktime_get();
1990         int ret;
1991         unsigned long count = 0;
1992         unsigned long actual_count = 0;
1993
1994         delayed_refs = &trans->transaction->delayed_refs;
1995         do {
1996                 if (!locked_ref) {
1997                         locked_ref = btrfs_obtain_ref_head(trans);
1998                         if (IS_ERR_OR_NULL(locked_ref)) {
1999                                 if (PTR_ERR(locked_ref) == -EAGAIN) {
2000                                         continue;
2001                                 } else {
2002                                         break;
2003                                 }
2004                         }
2005                         count++;
2006                 }
2007                 /*
2008                  * We need to try and merge add/drops of the same ref since we
2009                  * can run into issues with relocate dropping the implicit ref
2010                  * and then it being added back again before the drop can
2011                  * finish.  If we merged anything we need to re-loop so we can
2012                  * get a good ref.
2013                  * Or we can get node references of the same type that weren't
2014                  * merged when created due to bumps in the tree mod seq, and
2015                  * we need to merge them to prevent adding an inline extent
2016                  * backref before dropping it (triggering a BUG_ON at
2017                  * insert_inline_extent_backref()).
2018                  */
2019                 spin_lock(&locked_ref->lock);
2020                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2021
2022                 ret = btrfs_run_delayed_refs_for_head(trans, locked_ref,
2023                                                       &actual_count);
2024                 if (ret < 0 && ret != -EAGAIN) {
2025                         /*
2026                          * Error, btrfs_run_delayed_refs_for_head already
2027                          * unlocked everything so just bail out
2028                          */
2029                         return ret;
2030                 } else if (!ret) {
2031                         /*
2032                          * Success, perform the usual cleanup of a processed
2033                          * head
2034                          */
2035                         ret = cleanup_ref_head(trans, locked_ref);
2036                         if (ret > 0 ) {
2037                                 /* We dropped our lock, we need to loop. */
2038                                 ret = 0;
2039                                 continue;
2040                         } else if (ret) {
2041                                 return ret;
2042                         }
2043                 }
2044
2045                 /*
2046                  * Either success case or btrfs_run_delayed_refs_for_head
2047                  * returned -EAGAIN, meaning we need to select another head
2048                  */
2049
2050                 locked_ref = NULL;
2051                 cond_resched();
2052         } while ((nr != -1 && count < nr) || locked_ref);
2053
2054         /*
2055          * We don't want to include ref heads since we can have empty ref heads
2056          * and those will drastically skew our runtime down since we just do
2057          * accounting, no actual extent tree updates.
2058          */
2059         if (actual_count > 0) {
2060                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2061                 u64 avg;
2062
2063                 /*
2064                  * We weigh the current average higher than our current runtime
2065                  * to avoid large swings in the average.
2066                  */
2067                 spin_lock(&delayed_refs->lock);
2068                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2069                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2070                 spin_unlock(&delayed_refs->lock);
2071         }
2072         return 0;
2073 }
2074
2075 #ifdef SCRAMBLE_DELAYED_REFS
2076 /*
2077  * Normally delayed refs get processed in ascending bytenr order. This
2078  * correlates in most cases to the order added. To expose dependencies on this
2079  * order, we start to process the tree in the middle instead of the beginning
2080  */
2081 static u64 find_middle(struct rb_root *root)
2082 {
2083         struct rb_node *n = root->rb_node;
2084         struct btrfs_delayed_ref_node *entry;
2085         int alt = 1;
2086         u64 middle;
2087         u64 first = 0, last = 0;
2088
2089         n = rb_first(root);
2090         if (n) {
2091                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2092                 first = entry->bytenr;
2093         }
2094         n = rb_last(root);
2095         if (n) {
2096                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2097                 last = entry->bytenr;
2098         }
2099         n = root->rb_node;
2100
2101         while (n) {
2102                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2103                 WARN_ON(!entry->in_tree);
2104
2105                 middle = entry->bytenr;
2106
2107                 if (alt)
2108                         n = n->rb_left;
2109                 else
2110                         n = n->rb_right;
2111
2112                 alt = 1 - alt;
2113         }
2114         return middle;
2115 }
2116 #endif
2117
2118 /*
2119  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2120  * would require to store the csums for that many bytes.
2121  */
2122 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2123 {
2124         u64 csum_size;
2125         u64 num_csums_per_leaf;
2126         u64 num_csums;
2127
2128         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2129         num_csums_per_leaf = div64_u64(csum_size,
2130                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2131         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2132         num_csums += num_csums_per_leaf - 1;
2133         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2134         return num_csums;
2135 }
2136
2137 /*
2138  * this starts processing the delayed reference count updates and
2139  * extent insertions we have queued up so far.  count can be
2140  * 0, which means to process everything in the tree at the start
2141  * of the run (but not newly added entries), or it can be some target
2142  * number you'd like to process.
2143  *
2144  * Returns 0 on success or if called with an aborted transaction
2145  * Returns <0 on error and aborts the transaction
2146  */
2147 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2148                            unsigned long count)
2149 {
2150         struct btrfs_fs_info *fs_info = trans->fs_info;
2151         struct rb_node *node;
2152         struct btrfs_delayed_ref_root *delayed_refs;
2153         struct btrfs_delayed_ref_head *head;
2154         int ret;
2155         int run_all = count == (unsigned long)-1;
2156
2157         /* We'll clean this up in btrfs_cleanup_transaction */
2158         if (TRANS_ABORTED(trans))
2159                 return 0;
2160
2161         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2162                 return 0;
2163
2164         delayed_refs = &trans->transaction->delayed_refs;
2165         if (count == 0)
2166                 count = atomic_read(&delayed_refs->num_entries) * 2;
2167
2168 again:
2169 #ifdef SCRAMBLE_DELAYED_REFS
2170         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2171 #endif
2172         ret = __btrfs_run_delayed_refs(trans, count);
2173         if (ret < 0) {
2174                 btrfs_abort_transaction(trans, ret);
2175                 return ret;
2176         }
2177
2178         if (run_all) {
2179                 btrfs_create_pending_block_groups(trans);
2180
2181                 spin_lock(&delayed_refs->lock);
2182                 node = rb_first_cached(&delayed_refs->href_root);
2183                 if (!node) {
2184                         spin_unlock(&delayed_refs->lock);
2185                         goto out;
2186                 }
2187                 head = rb_entry(node, struct btrfs_delayed_ref_head,
2188                                 href_node);
2189                 refcount_inc(&head->refs);
2190                 spin_unlock(&delayed_refs->lock);
2191
2192                 /* Mutex was contended, block until it's released and retry. */
2193                 mutex_lock(&head->mutex);
2194                 mutex_unlock(&head->mutex);
2195
2196                 btrfs_put_delayed_ref_head(head);
2197                 cond_resched();
2198                 goto again;
2199         }
2200 out:
2201         return 0;
2202 }
2203
2204 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2205                                 struct extent_buffer *eb, u64 flags,
2206                                 int level, int is_data)
2207 {
2208         struct btrfs_delayed_extent_op *extent_op;
2209         int ret;
2210
2211         extent_op = btrfs_alloc_delayed_extent_op();
2212         if (!extent_op)
2213                 return -ENOMEM;
2214
2215         extent_op->flags_to_set = flags;
2216         extent_op->update_flags = true;
2217         extent_op->update_key = false;
2218         extent_op->is_data = is_data ? true : false;
2219         extent_op->level = level;
2220
2221         ret = btrfs_add_delayed_extent_op(trans, eb->start, eb->len, extent_op);
2222         if (ret)
2223                 btrfs_free_delayed_extent_op(extent_op);
2224         return ret;
2225 }
2226
2227 static noinline int check_delayed_ref(struct btrfs_root *root,
2228                                       struct btrfs_path *path,
2229                                       u64 objectid, u64 offset, u64 bytenr)
2230 {
2231         struct btrfs_delayed_ref_head *head;
2232         struct btrfs_delayed_ref_node *ref;
2233         struct btrfs_delayed_data_ref *data_ref;
2234         struct btrfs_delayed_ref_root *delayed_refs;
2235         struct btrfs_transaction *cur_trans;
2236         struct rb_node *node;
2237         int ret = 0;
2238
2239         spin_lock(&root->fs_info->trans_lock);
2240         cur_trans = root->fs_info->running_transaction;
2241         if (cur_trans)
2242                 refcount_inc(&cur_trans->use_count);
2243         spin_unlock(&root->fs_info->trans_lock);
2244         if (!cur_trans)
2245                 return 0;
2246
2247         delayed_refs = &cur_trans->delayed_refs;
2248         spin_lock(&delayed_refs->lock);
2249         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
2250         if (!head) {
2251                 spin_unlock(&delayed_refs->lock);
2252                 btrfs_put_transaction(cur_trans);
2253                 return 0;
2254         }
2255
2256         if (!mutex_trylock(&head->mutex)) {
2257                 refcount_inc(&head->refs);
2258                 spin_unlock(&delayed_refs->lock);
2259
2260                 btrfs_release_path(path);
2261
2262                 /*
2263                  * Mutex was contended, block until it's released and let
2264                  * caller try again
2265                  */
2266                 mutex_lock(&head->mutex);
2267                 mutex_unlock(&head->mutex);
2268                 btrfs_put_delayed_ref_head(head);
2269                 btrfs_put_transaction(cur_trans);
2270                 return -EAGAIN;
2271         }
2272         spin_unlock(&delayed_refs->lock);
2273
2274         spin_lock(&head->lock);
2275         /*
2276          * XXX: We should replace this with a proper search function in the
2277          * future.
2278          */
2279         for (node = rb_first_cached(&head->ref_tree); node;
2280              node = rb_next(node)) {
2281                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
2282                 /* If it's a shared ref we know a cross reference exists */
2283                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2284                         ret = 1;
2285                         break;
2286                 }
2287
2288                 data_ref = btrfs_delayed_node_to_data_ref(ref);
2289
2290                 /*
2291                  * If our ref doesn't match the one we're currently looking at
2292                  * then we have a cross reference.
2293                  */
2294                 if (data_ref->root != root->root_key.objectid ||
2295                     data_ref->objectid != objectid ||
2296                     data_ref->offset != offset) {
2297                         ret = 1;
2298                         break;
2299                 }
2300         }
2301         spin_unlock(&head->lock);
2302         mutex_unlock(&head->mutex);
2303         btrfs_put_transaction(cur_trans);
2304         return ret;
2305 }
2306
2307 static noinline int check_committed_ref(struct btrfs_root *root,
2308                                         struct btrfs_path *path,
2309                                         u64 objectid, u64 offset, u64 bytenr,
2310                                         bool strict)
2311 {
2312         struct btrfs_fs_info *fs_info = root->fs_info;
2313         struct btrfs_root *extent_root = fs_info->extent_root;
2314         struct extent_buffer *leaf;
2315         struct btrfs_extent_data_ref *ref;
2316         struct btrfs_extent_inline_ref *iref;
2317         struct btrfs_extent_item *ei;
2318         struct btrfs_key key;
2319         u32 item_size;
2320         int type;
2321         int ret;
2322
2323         key.objectid = bytenr;
2324         key.offset = (u64)-1;
2325         key.type = BTRFS_EXTENT_ITEM_KEY;
2326
2327         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2328         if (ret < 0)
2329                 goto out;
2330         BUG_ON(ret == 0); /* Corruption */
2331
2332         ret = -ENOENT;
2333         if (path->slots[0] == 0)
2334                 goto out;
2335
2336         path->slots[0]--;
2337         leaf = path->nodes[0];
2338         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2339
2340         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2341                 goto out;
2342
2343         ret = 1;
2344         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2345         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2346
2347         /* If extent item has more than 1 inline ref then it's shared */
2348         if (item_size != sizeof(*ei) +
2349             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2350                 goto out;
2351
2352         /*
2353          * If extent created before last snapshot => it's shared unless the
2354          * snapshot has been deleted. Use the heuristic if strict is false.
2355          */
2356         if (!strict &&
2357             (btrfs_extent_generation(leaf, ei) <=
2358              btrfs_root_last_snapshot(&root->root_item)))
2359                 goto out;
2360
2361         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2362
2363         /* If this extent has SHARED_DATA_REF then it's shared */
2364         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
2365         if (type != BTRFS_EXTENT_DATA_REF_KEY)
2366                 goto out;
2367
2368         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2369         if (btrfs_extent_refs(leaf, ei) !=
2370             btrfs_extent_data_ref_count(leaf, ref) ||
2371             btrfs_extent_data_ref_root(leaf, ref) !=
2372             root->root_key.objectid ||
2373             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2374             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2375                 goto out;
2376
2377         ret = 0;
2378 out:
2379         return ret;
2380 }
2381
2382 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
2383                           u64 bytenr, bool strict)
2384 {
2385         struct btrfs_path *path;
2386         int ret;
2387
2388         path = btrfs_alloc_path();
2389         if (!path)
2390                 return -ENOMEM;
2391
2392         do {
2393                 ret = check_committed_ref(root, path, objectid,
2394                                           offset, bytenr, strict);
2395                 if (ret && ret != -ENOENT)
2396                         goto out;
2397
2398                 ret = check_delayed_ref(root, path, objectid, offset, bytenr);
2399         } while (ret == -EAGAIN);
2400
2401 out:
2402         btrfs_free_path(path);
2403         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2404                 WARN_ON(ret > 0);
2405         return ret;
2406 }
2407
2408 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2409                            struct btrfs_root *root,
2410                            struct extent_buffer *buf,
2411                            int full_backref, int inc)
2412 {
2413         struct btrfs_fs_info *fs_info = root->fs_info;
2414         u64 bytenr;
2415         u64 num_bytes;
2416         u64 parent;
2417         u64 ref_root;
2418         u32 nritems;
2419         struct btrfs_key key;
2420         struct btrfs_file_extent_item *fi;
2421         struct btrfs_ref generic_ref = { 0 };
2422         bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC);
2423         int i;
2424         int action;
2425         int level;
2426         int ret = 0;
2427
2428         if (btrfs_is_testing(fs_info))
2429                 return 0;
2430
2431         ref_root = btrfs_header_owner(buf);
2432         nritems = btrfs_header_nritems(buf);
2433         level = btrfs_header_level(buf);
2434
2435         if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && level == 0)
2436                 return 0;
2437
2438         if (full_backref)
2439                 parent = buf->start;
2440         else
2441                 parent = 0;
2442         if (inc)
2443                 action = BTRFS_ADD_DELAYED_REF;
2444         else
2445                 action = BTRFS_DROP_DELAYED_REF;
2446
2447         for (i = 0; i < nritems; i++) {
2448                 if (level == 0) {
2449                         btrfs_item_key_to_cpu(buf, &key, i);
2450                         if (key.type != BTRFS_EXTENT_DATA_KEY)
2451                                 continue;
2452                         fi = btrfs_item_ptr(buf, i,
2453                                             struct btrfs_file_extent_item);
2454                         if (btrfs_file_extent_type(buf, fi) ==
2455                             BTRFS_FILE_EXTENT_INLINE)
2456                                 continue;
2457                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2458                         if (bytenr == 0)
2459                                 continue;
2460
2461                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2462                         key.offset -= btrfs_file_extent_offset(buf, fi);
2463                         btrfs_init_generic_ref(&generic_ref, action, bytenr,
2464                                                num_bytes, parent);
2465                         generic_ref.real_root = root->root_key.objectid;
2466                         btrfs_init_data_ref(&generic_ref, ref_root, key.objectid,
2467                                             key.offset);
2468                         generic_ref.skip_qgroup = for_reloc;
2469                         if (inc)
2470                                 ret = btrfs_inc_extent_ref(trans, &generic_ref);
2471                         else
2472                                 ret = btrfs_free_extent(trans, &generic_ref);
2473                         if (ret)
2474                                 goto fail;
2475                 } else {
2476                         bytenr = btrfs_node_blockptr(buf, i);
2477                         num_bytes = fs_info->nodesize;
2478                         btrfs_init_generic_ref(&generic_ref, action, bytenr,
2479                                                num_bytes, parent);
2480                         generic_ref.real_root = root->root_key.objectid;
2481                         btrfs_init_tree_ref(&generic_ref, level - 1, ref_root);
2482                         generic_ref.skip_qgroup = for_reloc;
2483                         if (inc)
2484                                 ret = btrfs_inc_extent_ref(trans, &generic_ref);
2485                         else
2486                                 ret = btrfs_free_extent(trans, &generic_ref);
2487                         if (ret)
2488                                 goto fail;
2489                 }
2490         }
2491         return 0;
2492 fail:
2493         return ret;
2494 }
2495
2496 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2497                   struct extent_buffer *buf, int full_backref)
2498 {
2499         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2500 }
2501
2502 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2503                   struct extent_buffer *buf, int full_backref)
2504 {
2505         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2506 }
2507
2508 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
2509 {
2510         struct btrfs_block_group *block_group;
2511         int readonly = 0;
2512
2513         block_group = btrfs_lookup_block_group(fs_info, bytenr);
2514         if (!block_group || block_group->ro)
2515                 readonly = 1;
2516         if (block_group)
2517                 btrfs_put_block_group(block_group);
2518         return readonly;
2519 }
2520
2521 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
2522 {
2523         struct btrfs_fs_info *fs_info = root->fs_info;
2524         u64 flags;
2525         u64 ret;
2526
2527         if (data)
2528                 flags = BTRFS_BLOCK_GROUP_DATA;
2529         else if (root == fs_info->chunk_root)
2530                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
2531         else
2532                 flags = BTRFS_BLOCK_GROUP_METADATA;
2533
2534         ret = btrfs_get_alloc_profile(fs_info, flags);
2535         return ret;
2536 }
2537
2538 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
2539 {
2540         struct btrfs_block_group *cache;
2541         u64 bytenr;
2542
2543         spin_lock(&fs_info->block_group_cache_lock);
2544         bytenr = fs_info->first_logical_byte;
2545         spin_unlock(&fs_info->block_group_cache_lock);
2546
2547         if (bytenr < (u64)-1)
2548                 return bytenr;
2549
2550         cache = btrfs_lookup_first_block_group(fs_info, search_start);
2551         if (!cache)
2552                 return 0;
2553
2554         bytenr = cache->start;
2555         btrfs_put_block_group(cache);
2556
2557         return bytenr;
2558 }
2559
2560 static int pin_down_extent(struct btrfs_trans_handle *trans,
2561                            struct btrfs_block_group *cache,
2562                            u64 bytenr, u64 num_bytes, int reserved)
2563 {
2564         struct btrfs_fs_info *fs_info = cache->fs_info;
2565
2566         spin_lock(&cache->space_info->lock);
2567         spin_lock(&cache->lock);
2568         cache->pinned += num_bytes;
2569         btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,
2570                                              num_bytes);
2571         if (reserved) {
2572                 cache->reserved -= num_bytes;
2573                 cache->space_info->bytes_reserved -= num_bytes;
2574         }
2575         spin_unlock(&cache->lock);
2576         spin_unlock(&cache->space_info->lock);
2577
2578         percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
2579                     num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
2580         set_extent_dirty(&trans->transaction->pinned_extents, bytenr,
2581                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
2582         return 0;
2583 }
2584
2585 int btrfs_pin_extent(struct btrfs_trans_handle *trans,
2586                      u64 bytenr, u64 num_bytes, int reserved)
2587 {
2588         struct btrfs_block_group *cache;
2589
2590         cache = btrfs_lookup_block_group(trans->fs_info, bytenr);
2591         BUG_ON(!cache); /* Logic error */
2592
2593         pin_down_extent(trans, cache, bytenr, num_bytes, reserved);
2594
2595         btrfs_put_block_group(cache);
2596         return 0;
2597 }
2598
2599 /*
2600  * this function must be called within transaction
2601  */
2602 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
2603                                     u64 bytenr, u64 num_bytes)
2604 {
2605         struct btrfs_block_group *cache;
2606         int ret;
2607
2608         btrfs_add_excluded_extent(trans->fs_info, bytenr, num_bytes);
2609
2610         cache = btrfs_lookup_block_group(trans->fs_info, bytenr);
2611         if (!cache)
2612                 return -EINVAL;
2613
2614         /*
2615          * pull in the free space cache (if any) so that our pin
2616          * removes the free space from the cache.  We have load_only set
2617          * to one because the slow code to read in the free extents does check
2618          * the pinned extents.
2619          */
2620         btrfs_cache_block_group(cache, 1);
2621
2622         pin_down_extent(trans, cache, bytenr, num_bytes, 0);
2623
2624         /* remove us from the free space cache (if we're there at all) */
2625         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
2626         btrfs_put_block_group(cache);
2627         return ret;
2628 }
2629
2630 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
2631                                    u64 start, u64 num_bytes)
2632 {
2633         int ret;
2634         struct btrfs_block_group *block_group;
2635         struct btrfs_caching_control *caching_ctl;
2636
2637         block_group = btrfs_lookup_block_group(fs_info, start);
2638         if (!block_group)
2639                 return -EINVAL;
2640
2641         btrfs_cache_block_group(block_group, 0);
2642         caching_ctl = btrfs_get_caching_control(block_group);
2643
2644         if (!caching_ctl) {
2645                 /* Logic error */
2646                 BUG_ON(!btrfs_block_group_done(block_group));
2647                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
2648         } else {
2649                 mutex_lock(&caching_ctl->mutex);
2650
2651                 if (start >= caching_ctl->progress) {
2652                         ret = btrfs_add_excluded_extent(fs_info, start,
2653                                                         num_bytes);
2654                 } else if (start + num_bytes <= caching_ctl->progress) {
2655                         ret = btrfs_remove_free_space(block_group,
2656                                                       start, num_bytes);
2657                 } else {
2658                         num_bytes = caching_ctl->progress - start;
2659                         ret = btrfs_remove_free_space(block_group,
2660                                                       start, num_bytes);
2661                         if (ret)
2662                                 goto out_lock;
2663
2664                         num_bytes = (start + num_bytes) -
2665                                 caching_ctl->progress;
2666                         start = caching_ctl->progress;
2667                         ret = btrfs_add_excluded_extent(fs_info, start,
2668                                                         num_bytes);
2669                 }
2670 out_lock:
2671                 mutex_unlock(&caching_ctl->mutex);
2672                 btrfs_put_caching_control(caching_ctl);
2673         }
2674         btrfs_put_block_group(block_group);
2675         return ret;
2676 }
2677
2678 int btrfs_exclude_logged_extents(struct extent_buffer *eb)
2679 {
2680         struct btrfs_fs_info *fs_info = eb->fs_info;
2681         struct btrfs_file_extent_item *item;
2682         struct btrfs_key key;
2683         int found_type;
2684         int i;
2685         int ret = 0;
2686
2687         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
2688                 return 0;
2689
2690         for (i = 0; i < btrfs_header_nritems(eb); i++) {
2691                 btrfs_item_key_to_cpu(eb, &key, i);
2692                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2693                         continue;
2694                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
2695                 found_type = btrfs_file_extent_type(eb, item);
2696                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
2697                         continue;
2698                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
2699                         continue;
2700                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
2701                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
2702                 ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
2703                 if (ret)
2704                         break;
2705         }
2706
2707         return ret;
2708 }
2709
2710 static void
2711 btrfs_inc_block_group_reservations(struct btrfs_block_group *bg)
2712 {
2713         atomic_inc(&bg->reservations);
2714 }
2715
2716 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
2717 {
2718         struct btrfs_caching_control *next;
2719         struct btrfs_caching_control *caching_ctl;
2720         struct btrfs_block_group *cache;
2721
2722         down_write(&fs_info->commit_root_sem);
2723
2724         list_for_each_entry_safe(caching_ctl, next,
2725                                  &fs_info->caching_block_groups, list) {
2726                 cache = caching_ctl->block_group;
2727                 if (btrfs_block_group_done(cache)) {
2728                         cache->last_byte_to_unpin = (u64)-1;
2729                         list_del_init(&caching_ctl->list);
2730                         btrfs_put_caching_control(caching_ctl);
2731                 } else {
2732                         cache->last_byte_to_unpin = caching_ctl->progress;
2733                 }
2734         }
2735
2736         up_write(&fs_info->commit_root_sem);
2737
2738         btrfs_update_global_block_rsv(fs_info);
2739 }
2740
2741 /*
2742  * Returns the free cluster for the given space info and sets empty_cluster to
2743  * what it should be based on the mount options.
2744  */
2745 static struct btrfs_free_cluster *
2746 fetch_cluster_info(struct btrfs_fs_info *fs_info,
2747                    struct btrfs_space_info *space_info, u64 *empty_cluster)
2748 {
2749         struct btrfs_free_cluster *ret = NULL;
2750
2751         *empty_cluster = 0;
2752         if (btrfs_mixed_space_info(space_info))
2753                 return ret;
2754
2755         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
2756                 ret = &fs_info->meta_alloc_cluster;
2757                 if (btrfs_test_opt(fs_info, SSD))
2758                         *empty_cluster = SZ_2M;
2759                 else
2760                         *empty_cluster = SZ_64K;
2761         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
2762                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
2763                 *empty_cluster = SZ_2M;
2764                 ret = &fs_info->data_alloc_cluster;
2765         }
2766
2767         return ret;
2768 }
2769
2770 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
2771                               u64 start, u64 end,
2772                               const bool return_free_space)
2773 {
2774         struct btrfs_block_group *cache = NULL;
2775         struct btrfs_space_info *space_info;
2776         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
2777         struct btrfs_free_cluster *cluster = NULL;
2778         u64 len;
2779         u64 total_unpinned = 0;
2780         u64 empty_cluster = 0;
2781         bool readonly;
2782
2783         while (start <= end) {
2784                 readonly = false;
2785                 if (!cache ||
2786                     start >= cache->start + cache->length) {
2787                         if (cache)
2788                                 btrfs_put_block_group(cache);
2789                         total_unpinned = 0;
2790                         cache = btrfs_lookup_block_group(fs_info, start);
2791                         BUG_ON(!cache); /* Logic error */
2792
2793                         cluster = fetch_cluster_info(fs_info,
2794                                                      cache->space_info,
2795                                                      &empty_cluster);
2796                         empty_cluster <<= 1;
2797                 }
2798
2799                 len = cache->start + cache->length - start;
2800                 len = min(len, end + 1 - start);
2801
2802                 if (start < cache->last_byte_to_unpin) {
2803                         len = min(len, cache->last_byte_to_unpin - start);
2804                         if (return_free_space)
2805                                 btrfs_add_free_space(cache, start, len);
2806                 }
2807
2808                 start += len;
2809                 total_unpinned += len;
2810                 space_info = cache->space_info;
2811
2812                 /*
2813                  * If this space cluster has been marked as fragmented and we've
2814                  * unpinned enough in this block group to potentially allow a
2815                  * cluster to be created inside of it go ahead and clear the
2816                  * fragmented check.
2817                  */
2818                 if (cluster && cluster->fragmented &&
2819                     total_unpinned > empty_cluster) {
2820                         spin_lock(&cluster->lock);
2821                         cluster->fragmented = 0;
2822                         spin_unlock(&cluster->lock);
2823                 }
2824
2825                 spin_lock(&space_info->lock);
2826                 spin_lock(&cache->lock);
2827                 cache->pinned -= len;
2828                 btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
2829                 space_info->max_extent_size = 0;
2830                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
2831                             -len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
2832                 if (cache->ro) {
2833                         space_info->bytes_readonly += len;
2834                         readonly = true;
2835                 }
2836                 spin_unlock(&cache->lock);
2837                 if (!readonly && return_free_space &&
2838                     global_rsv->space_info == space_info) {
2839                         u64 to_add = len;
2840
2841                         spin_lock(&global_rsv->lock);
2842                         if (!global_rsv->full) {
2843                                 to_add = min(len, global_rsv->size -
2844                                              global_rsv->reserved);
2845                                 global_rsv->reserved += to_add;
2846                                 btrfs_space_info_update_bytes_may_use(fs_info,
2847                                                 space_info, to_add);
2848                                 if (global_rsv->reserved >= global_rsv->size)
2849                                         global_rsv->full = 1;
2850                                 len -= to_add;
2851                         }
2852                         spin_unlock(&global_rsv->lock);
2853                         /* Add to any tickets we may have */
2854                         if (len)
2855                                 btrfs_try_granting_tickets(fs_info,
2856                                                            space_info);
2857                 }
2858                 spin_unlock(&space_info->lock);
2859         }
2860
2861         if (cache)
2862                 btrfs_put_block_group(cache);
2863         return 0;
2864 }
2865
2866 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
2867 {
2868         struct btrfs_fs_info *fs_info = trans->fs_info;
2869         struct btrfs_block_group *block_group, *tmp;
2870         struct list_head *deleted_bgs;
2871         struct extent_io_tree *unpin;
2872         u64 start;
2873         u64 end;
2874         int ret;
2875
2876         unpin = &trans->transaction->pinned_extents;
2877
2878         while (!TRANS_ABORTED(trans)) {
2879                 struct extent_state *cached_state = NULL;
2880
2881                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
2882                 ret = find_first_extent_bit(unpin, 0, &start, &end,
2883                                             EXTENT_DIRTY, &cached_state);
2884                 if (ret) {
2885                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
2886                         break;
2887                 }
2888                 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
2889                         clear_extent_bits(&fs_info->excluded_extents, start,
2890                                           end, EXTENT_UPTODATE);
2891
2892                 if (btrfs_test_opt(fs_info, DISCARD_SYNC))
2893                         ret = btrfs_discard_extent(fs_info, start,
2894                                                    end + 1 - start, NULL);
2895
2896                 clear_extent_dirty(unpin, start, end, &cached_state);
2897                 unpin_extent_range(fs_info, start, end, true);
2898                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
2899                 free_extent_state(cached_state);
2900                 cond_resched();
2901         }
2902
2903         if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) {
2904                 btrfs_discard_calc_delay(&fs_info->discard_ctl);
2905                 btrfs_discard_schedule_work(&fs_info->discard_ctl, true);
2906         }
2907
2908         /*
2909          * Transaction is finished.  We don't need the lock anymore.  We
2910          * do need to clean up the block groups in case of a transaction
2911          * abort.
2912          */
2913         deleted_bgs = &trans->transaction->deleted_bgs;
2914         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
2915                 u64 trimmed = 0;
2916
2917                 ret = -EROFS;
2918                 if (!TRANS_ABORTED(trans))
2919                         ret = btrfs_discard_extent(fs_info,
2920                                                    block_group->start,
2921                                                    block_group->length,
2922                                                    &trimmed);
2923
2924                 list_del_init(&block_group->bg_list);
2925                 btrfs_unfreeze_block_group(block_group);
2926                 btrfs_put_block_group(block_group);
2927
2928                 if (ret) {
2929                         const char *errstr = btrfs_decode_error(ret);
2930                         btrfs_warn(fs_info,
2931                            "discard failed while removing blockgroup: errno=%d %s",
2932                                    ret, errstr);
2933                 }
2934         }
2935
2936         return 0;
2937 }
2938
2939 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
2940                                struct btrfs_delayed_ref_node *node, u64 parent,
2941                                u64 root_objectid, u64 owner_objectid,
2942                                u64 owner_offset, int refs_to_drop,
2943                                struct btrfs_delayed_extent_op *extent_op)
2944 {
2945         struct btrfs_fs_info *info = trans->fs_info;
2946         struct btrfs_key key;
2947         struct btrfs_path *path;
2948         struct btrfs_root *extent_root = info->extent_root;
2949         struct extent_buffer *leaf;
2950         struct btrfs_extent_item *ei;
2951         struct btrfs_extent_inline_ref *iref;
2952         int ret;
2953         int is_data;
2954         int extent_slot = 0;
2955         int found_extent = 0;
2956         int num_to_del = 1;
2957         u32 item_size;
2958         u64 refs;
2959         u64 bytenr = node->bytenr;
2960         u64 num_bytes = node->num_bytes;
2961         int last_ref = 0;
2962         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
2963
2964         path = btrfs_alloc_path();
2965         if (!path)
2966                 return -ENOMEM;
2967
2968         path->leave_spinning = 1;
2969
2970         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
2971         BUG_ON(!is_data && refs_to_drop != 1);
2972
2973         if (is_data)
2974                 skinny_metadata = false;
2975
2976         ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
2977                                     parent, root_objectid, owner_objectid,
2978                                     owner_offset);
2979         if (ret == 0) {
2980                 extent_slot = path->slots[0];
2981                 while (extent_slot >= 0) {
2982                         btrfs_item_key_to_cpu(path->nodes[0], &key,
2983                                               extent_slot);
2984                         if (key.objectid != bytenr)
2985                                 break;
2986                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
2987                             key.offset == num_bytes) {
2988                                 found_extent = 1;
2989                                 break;
2990                         }
2991                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
2992                             key.offset == owner_objectid) {
2993                                 found_extent = 1;
2994                                 break;
2995                         }
2996                         if (path->slots[0] - extent_slot > 5)
2997                                 break;
2998                         extent_slot--;
2999                 }
3000
3001                 if (!found_extent) {
3002                         BUG_ON(iref);
3003                         ret = remove_extent_backref(trans, path, NULL,
3004                                                     refs_to_drop,
3005                                                     is_data, &last_ref);
3006                         if (ret) {
3007                                 btrfs_abort_transaction(trans, ret);
3008                                 goto out;
3009                         }
3010                         btrfs_release_path(path);
3011                         path->leave_spinning = 1;
3012
3013                         key.objectid = bytenr;
3014                         key.type = BTRFS_EXTENT_ITEM_KEY;
3015                         key.offset = num_bytes;
3016
3017                         if (!is_data && skinny_metadata) {
3018                                 key.type = BTRFS_METADATA_ITEM_KEY;
3019                                 key.offset = owner_objectid;
3020                         }
3021
3022                         ret = btrfs_search_slot(trans, extent_root,
3023                                                 &key, path, -1, 1);
3024                         if (ret > 0 && skinny_metadata && path->slots[0]) {
3025                                 /*
3026                                  * Couldn't find our skinny metadata item,
3027                                  * see if we have ye olde extent item.
3028                                  */
3029                                 path->slots[0]--;
3030                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
3031                                                       path->slots[0]);
3032                                 if (key.objectid == bytenr &&
3033                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
3034                                     key.offset == num_bytes)
3035                                         ret = 0;
3036                         }
3037
3038                         if (ret > 0 && skinny_metadata) {
3039                                 skinny_metadata = false;
3040                                 key.objectid = bytenr;
3041                                 key.type = BTRFS_EXTENT_ITEM_KEY;
3042                                 key.offset = num_bytes;
3043                                 btrfs_release_path(path);
3044                                 ret = btrfs_search_slot(trans, extent_root,
3045                                                         &key, path, -1, 1);
3046                         }
3047
3048                         if (ret) {
3049                                 btrfs_err(info,
3050                                           "umm, got %d back from search, was looking for %llu",
3051                                           ret, bytenr);
3052                                 if (ret > 0)
3053                                         btrfs_print_leaf(path->nodes[0]);
3054                         }
3055                         if (ret < 0) {
3056                                 btrfs_abort_transaction(trans, ret);
3057                                 goto out;
3058                         }
3059                         extent_slot = path->slots[0];
3060                 }
3061         } else if (WARN_ON(ret == -ENOENT)) {
3062                 btrfs_print_leaf(path->nodes[0]);
3063                 btrfs_err(info,
3064                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
3065                         bytenr, parent, root_objectid, owner_objectid,
3066                         owner_offset);
3067                 btrfs_abort_transaction(trans, ret);
3068                 goto out;
3069         } else {
3070                 btrfs_abort_transaction(trans, ret);
3071                 goto out;
3072         }
3073
3074         leaf = path->nodes[0];
3075         item_size = btrfs_item_size_nr(leaf, extent_slot);
3076         if (unlikely(item_size < sizeof(*ei))) {
3077                 ret = -EINVAL;
3078                 btrfs_print_v0_err(info);
3079                 btrfs_abort_transaction(trans, ret);
3080                 goto out;
3081         }
3082         ei = btrfs_item_ptr(leaf, extent_slot,
3083                             struct btrfs_extent_item);
3084         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
3085             key.type == BTRFS_EXTENT_ITEM_KEY) {
3086                 struct btrfs_tree_block_info *bi;
3087                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
3088                 bi = (struct btrfs_tree_block_info *)(ei + 1);
3089                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
3090         }
3091
3092         refs = btrfs_extent_refs(leaf, ei);
3093         if (refs < refs_to_drop) {
3094                 btrfs_err(info,
3095                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
3096                           refs_to_drop, refs, bytenr);
3097                 ret = -EINVAL;
3098                 btrfs_abort_transaction(trans, ret);
3099                 goto out;
3100         }
3101         refs -= refs_to_drop;
3102
3103         if (refs > 0) {
3104                 if (extent_op)
3105                         __run_delayed_extent_op(extent_op, leaf, ei);
3106                 /*
3107                  * In the case of inline back ref, reference count will
3108                  * be updated by remove_extent_backref
3109                  */
3110                 if (iref) {
3111                         BUG_ON(!found_extent);
3112                 } else {
3113                         btrfs_set_extent_refs(leaf, ei, refs);
3114                         btrfs_mark_buffer_dirty(leaf);
3115                 }
3116                 if (found_extent) {
3117                         ret = remove_extent_backref(trans, path, iref,
3118                                                     refs_to_drop, is_data,
3119                                                     &last_ref);
3120                         if (ret) {
3121                                 btrfs_abort_transaction(trans, ret);
3122                                 goto out;
3123                         }
3124                 }
3125         } else {
3126                 if (found_extent) {
3127                         BUG_ON(is_data && refs_to_drop !=
3128                                extent_data_ref_count(path, iref));
3129                         if (iref) {
3130                                 BUG_ON(path->slots[0] != extent_slot);
3131                         } else {
3132                                 BUG_ON(path->slots[0] != extent_slot + 1);
3133                                 path->slots[0] = extent_slot;
3134                                 num_to_del = 2;
3135                         }
3136                 }
3137
3138                 last_ref = 1;
3139                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
3140                                       num_to_del);
3141                 if (ret) {
3142                         btrfs_abort_transaction(trans, ret);
3143                         goto out;
3144                 }
3145                 btrfs_release_path(path);
3146
3147                 if (is_data) {
3148                         ret = btrfs_del_csums(trans, info->csum_root, bytenr,
3149                                               num_bytes);
3150                         if (ret) {
3151                                 btrfs_abort_transaction(trans, ret);
3152                                 goto out;
3153                         }
3154                 }
3155
3156                 ret = add_to_free_space_tree(trans, bytenr, num_bytes);
3157                 if (ret) {
3158                         btrfs_abort_transaction(trans, ret);
3159                         goto out;
3160                 }
3161
3162                 ret = btrfs_update_block_group(trans, bytenr, num_bytes, 0);
3163                 if (ret) {
3164                         btrfs_abort_transaction(trans, ret);
3165                         goto out;
3166                 }
3167         }
3168         btrfs_release_path(path);
3169
3170 out:
3171         btrfs_free_path(path);
3172         return ret;
3173 }
3174
3175 /*
3176  * when we free an block, it is possible (and likely) that we free the last
3177  * delayed ref for that extent as well.  This searches the delayed ref tree for
3178  * a given extent, and if there are no other delayed refs to be processed, it
3179  * removes it from the tree.
3180  */
3181 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
3182                                       u64 bytenr)
3183 {
3184         struct btrfs_delayed_ref_head *head;
3185         struct btrfs_delayed_ref_root *delayed_refs;
3186         int ret = 0;
3187
3188         delayed_refs = &trans->transaction->delayed_refs;
3189         spin_lock(&delayed_refs->lock);
3190         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3191         if (!head)
3192                 goto out_delayed_unlock;
3193
3194         spin_lock(&head->lock);
3195         if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
3196                 goto out;
3197
3198         if (cleanup_extent_op(head) != NULL)
3199                 goto out;
3200
3201         /*
3202          * waiting for the lock here would deadlock.  If someone else has it
3203          * locked they are already in the process of dropping it anyway
3204          */
3205         if (!mutex_trylock(&head->mutex))
3206                 goto out;
3207
3208         btrfs_delete_ref_head(delayed_refs, head);
3209         head->processing = 0;
3210
3211         spin_unlock(&head->lock);
3212         spin_unlock(&delayed_refs->lock);
3213
3214         BUG_ON(head->extent_op);
3215         if (head->must_insert_reserved)
3216                 ret = 1;
3217
3218         btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head);
3219         mutex_unlock(&head->mutex);
3220         btrfs_put_delayed_ref_head(head);
3221         return ret;
3222 out:
3223         spin_unlock(&head->lock);
3224
3225 out_delayed_unlock:
3226         spin_unlock(&delayed_refs->lock);
3227         return 0;
3228 }
3229
3230 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
3231                            struct btrfs_root *root,
3232                            struct extent_buffer *buf,
3233                            u64 parent, int last_ref)
3234 {
3235         struct btrfs_fs_info *fs_info = root->fs_info;
3236         struct btrfs_ref generic_ref = { 0 };
3237         int pin = 1;
3238         int ret;
3239
3240         btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
3241                                buf->start, buf->len, parent);
3242         btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
3243                             root->root_key.objectid);
3244
3245         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
3246                 int old_ref_mod, new_ref_mod;
3247
3248                 btrfs_ref_tree_mod(fs_info, &generic_ref);
3249                 ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL,
3250                                                  &old_ref_mod, &new_ref_mod);
3251                 BUG_ON(ret); /* -ENOMEM */
3252                 pin = old_ref_mod >= 0 && new_ref_mod < 0;
3253         }
3254
3255         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
3256                 struct btrfs_block_group *cache;
3257
3258                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
3259                         ret = check_ref_cleanup(trans, buf->start);
3260                         if (!ret)
3261                                 goto out;
3262                 }
3263
3264                 pin = 0;
3265                 cache = btrfs_lookup_block_group(fs_info, buf->start);
3266
3267                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
3268                         pin_down_extent(trans, cache, buf->start, buf->len, 1);
3269                         btrfs_put_block_group(cache);
3270                         goto out;
3271                 }
3272
3273                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
3274
3275                 btrfs_add_free_space(cache, buf->start, buf->len);
3276                 btrfs_free_reserved_bytes(cache, buf->len, 0);
3277                 btrfs_put_block_group(cache);
3278                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
3279         }
3280 out:
3281         if (pin)
3282                 add_pinned_bytes(fs_info, &generic_ref);
3283
3284         if (last_ref) {
3285                 /*
3286                  * Deleting the buffer, clear the corrupt flag since it doesn't
3287                  * matter anymore.
3288                  */
3289                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
3290         }
3291 }
3292
3293 /* Can return -ENOMEM */
3294 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
3295 {
3296         struct btrfs_fs_info *fs_info = trans->fs_info;
3297         int old_ref_mod, new_ref_mod;
3298         int ret;
3299
3300         if (btrfs_is_testing(fs_info))
3301                 return 0;
3302
3303         /*
3304          * tree log blocks never actually go into the extent allocation
3305          * tree, just update pinning info and exit early.
3306          */
3307         if ((ref->type == BTRFS_REF_METADATA &&
3308              ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
3309             (ref->type == BTRFS_REF_DATA &&
3310              ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)) {
3311                 /* unlocks the pinned mutex */
3312                 btrfs_pin_extent(trans, ref->bytenr, ref->len, 1);
3313                 old_ref_mod = new_ref_mod = 0;
3314                 ret = 0;
3315         } else if (ref->type == BTRFS_REF_METADATA) {
3316                 ret = btrfs_add_delayed_tree_ref(trans, ref, NULL,
3317                                                  &old_ref_mod, &new_ref_mod);
3318         } else {
3319                 ret = btrfs_add_delayed_data_ref(trans, ref, 0,
3320                                                  &old_ref_mod, &new_ref_mod);
3321         }
3322
3323         if (!((ref->type == BTRFS_REF_METADATA &&
3324                ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
3325               (ref->type == BTRFS_REF_DATA &&
3326                ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)))
3327                 btrfs_ref_tree_mod(fs_info, ref);
3328
3329         if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
3330                 add_pinned_bytes(fs_info, ref);
3331
3332         return ret;
3333 }
3334
3335 enum btrfs_loop_type {
3336         LOOP_CACHING_NOWAIT,
3337         LOOP_CACHING_WAIT,
3338         LOOP_ALLOC_CHUNK,
3339         LOOP_NO_EMPTY_SIZE,
3340 };
3341
3342 static inline void
3343 btrfs_lock_block_group(struct btrfs_block_group *cache,
3344                        int delalloc)
3345 {
3346         if (delalloc)
3347                 down_read(&cache->data_rwsem);
3348 }
3349
3350 static inline void btrfs_grab_block_group(struct btrfs_block_group *cache,
3351                        int delalloc)
3352 {
3353         btrfs_get_block_group(cache);
3354         if (delalloc)
3355                 down_read(&cache->data_rwsem);
3356 }
3357
3358 static struct btrfs_block_group *btrfs_lock_cluster(
3359                    struct btrfs_block_group *block_group,
3360                    struct btrfs_free_cluster *cluster,
3361                    int delalloc)
3362         __acquires(&cluster->refill_lock)
3363 {
3364         struct btrfs_block_group *used_bg = NULL;
3365
3366         spin_lock(&cluster->refill_lock);
3367         while (1) {
3368                 used_bg = cluster->block_group;
3369                 if (!used_bg)
3370                         return NULL;
3371
3372                 if (used_bg == block_group)
3373                         return used_bg;
3374
3375                 btrfs_get_block_group(used_bg);
3376
3377                 if (!delalloc)
3378                         return used_bg;
3379
3380                 if (down_read_trylock(&used_bg->data_rwsem))
3381                         return used_bg;
3382
3383                 spin_unlock(&cluster->refill_lock);
3384
3385                 /* We should only have one-level nested. */
3386                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
3387
3388                 spin_lock(&cluster->refill_lock);
3389                 if (used_bg == cluster->block_group)
3390                         return used_bg;
3391
3392                 up_read(&used_bg->data_rwsem);
3393                 btrfs_put_block_group(used_bg);
3394         }
3395 }
3396
3397 static inline void
3398 btrfs_release_block_group(struct btrfs_block_group *cache,
3399                          int delalloc)
3400 {
3401         if (delalloc)
3402                 up_read(&cache->data_rwsem);
3403         btrfs_put_block_group(cache);
3404 }
3405
3406 enum btrfs_extent_allocation_policy {
3407         BTRFS_EXTENT_ALLOC_CLUSTERED,
3408 };
3409
3410 /*
3411  * Structure used internally for find_free_extent() function.  Wraps needed
3412  * parameters.
3413  */
3414 struct find_free_extent_ctl {
3415         /* Basic allocation info */
3416         u64 num_bytes;
3417         u64 empty_size;
3418         u64 flags;
3419         int delalloc;
3420
3421         /* Where to start the search inside the bg */
3422         u64 search_start;
3423
3424         /* For clustered allocation */
3425         u64 empty_cluster;
3426         struct btrfs_free_cluster *last_ptr;
3427         bool use_cluster;
3428
3429         bool have_caching_bg;
3430         bool orig_have_caching_bg;
3431
3432         /* RAID index, converted from flags */
3433         int index;
3434
3435         /*
3436          * Current loop number, check find_free_extent_update_loop() for details
3437          */
3438         int loop;
3439
3440         /*
3441          * Whether we're refilling a cluster, if true we need to re-search
3442          * current block group but don't try to refill the cluster again.
3443          */
3444         bool retry_clustered;
3445
3446         /*
3447          * Whether we're updating free space cache, if true we need to re-search
3448          * current block group but don't try updating free space cache again.
3449          */
3450         bool retry_unclustered;
3451
3452         /* If current block group is cached */
3453         int cached;
3454
3455         /* Max contiguous hole found */
3456         u64 max_extent_size;
3457
3458         /* Total free space from free space cache, not always contiguous */
3459         u64 total_free_space;
3460
3461         /* Found result */
3462         u64 found_offset;
3463
3464         /* Hint where to start looking for an empty space */
3465         u64 hint_byte;
3466
3467         /* Allocation policy */
3468         enum btrfs_extent_allocation_policy policy;
3469 };
3470
3471
3472 /*
3473  * Helper function for find_free_extent().
3474  *
3475  * Return -ENOENT to inform caller that we need fallback to unclustered mode.
3476  * Return -EAGAIN to inform caller that we need to re-search this block group
3477  * Return >0 to inform caller that we find nothing
3478  * Return 0 means we have found a location and set ffe_ctl->found_offset.
3479  */
3480 static int find_free_extent_clustered(struct btrfs_block_group *bg,
3481                                       struct find_free_extent_ctl *ffe_ctl,
3482                                       struct btrfs_block_group **cluster_bg_ret)
3483 {
3484         struct btrfs_block_group *cluster_bg;
3485         struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3486         u64 aligned_cluster;
3487         u64 offset;
3488         int ret;
3489
3490         cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);
3491         if (!cluster_bg)
3492                 goto refill_cluster;
3493         if (cluster_bg != bg && (cluster_bg->ro ||
3494             !block_group_bits(cluster_bg, ffe_ctl->flags)))
3495                 goto release_cluster;
3496
3497         offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,
3498                         ffe_ctl->num_bytes, cluster_bg->start,
3499                         &ffe_ctl->max_extent_size);
3500         if (offset) {
3501                 /* We have a block, we're done */
3502                 spin_unlock(&last_ptr->refill_lock);
3503                 trace_btrfs_reserve_extent_cluster(cluster_bg,
3504                                 ffe_ctl->search_start, ffe_ctl->num_bytes);
3505                 *cluster_bg_ret = cluster_bg;
3506                 ffe_ctl->found_offset = offset;
3507                 return 0;
3508         }
3509         WARN_ON(last_ptr->block_group != cluster_bg);
3510
3511 release_cluster:
3512         /*
3513          * If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
3514          * lets just skip it and let the allocator find whatever block it can
3515          * find. If we reach this point, we will have tried the cluster
3516          * allocator plenty of times and not have found anything, so we are
3517          * likely way too fragmented for the clustering stuff to find anything.
3518          *
3519          * However, if the cluster is taken from the current block group,
3520          * release the cluster first, so that we stand a better chance of
3521          * succeeding in the unclustered allocation.
3522          */
3523         if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
3524                 spin_unlock(&last_ptr->refill_lock);
3525                 btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
3526                 return -ENOENT;
3527         }
3528
3529         /* This cluster didn't work out, free it and start over */
3530         btrfs_return_cluster_to_free_space(NULL, last_ptr);
3531
3532         if (cluster_bg != bg)
3533                 btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
3534
3535 refill_cluster:
3536         if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
3537                 spin_unlock(&last_ptr->refill_lock);
3538                 return -ENOENT;
3539         }
3540
3541         aligned_cluster = max_t(u64,
3542                         ffe_ctl->empty_cluster + ffe_ctl->empty_size,
3543                         bg->full_stripe_len);
3544         ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start,
3545                         ffe_ctl->num_bytes, aligned_cluster);
3546         if (ret == 0) {
3547                 /* Now pull our allocation out of this cluster */
3548                 offset = btrfs_alloc_from_cluster(bg, last_ptr,
3549                                 ffe_ctl->num_bytes, ffe_ctl->search_start,
3550                                 &ffe_ctl->max_extent_size);
3551                 if (offset) {
3552                         /* We found one, proceed */
3553                         spin_unlock(&last_ptr->refill_lock);
3554                         trace_btrfs_reserve_extent_cluster(bg,
3555                                         ffe_ctl->search_start,
3556                                         ffe_ctl->num_bytes);
3557                         ffe_ctl->found_offset = offset;
3558                         return 0;
3559                 }
3560         } else if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
3561                    !ffe_ctl->retry_clustered) {
3562                 spin_unlock(&last_ptr->refill_lock);
3563
3564                 ffe_ctl->retry_clustered = true;
3565                 btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
3566                                 ffe_ctl->empty_cluster + ffe_ctl->empty_size);
3567                 return -EAGAIN;
3568         }
3569         /*
3570          * At this point we either didn't find a cluster or we weren't able to
3571          * allocate a block from our cluster.  Free the cluster we've been
3572          * trying to use, and go to the next block group.
3573          */
3574         btrfs_return_cluster_to_free_space(NULL, last_ptr);
3575         spin_unlock(&last_ptr->refill_lock);
3576         return 1;
3577 }
3578
3579 /*
3580  * Return >0 to inform caller that we find nothing
3581  * Return 0 when we found an free extent and set ffe_ctrl->found_offset
3582  * Return -EAGAIN to inform caller that we need to re-search this block group
3583  */
3584 static int find_free_extent_unclustered(struct btrfs_block_group *bg,
3585                                         struct find_free_extent_ctl *ffe_ctl)
3586 {
3587         struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3588         u64 offset;
3589
3590         /*
3591          * We are doing an unclustered allocation, set the fragmented flag so
3592          * we don't bother trying to setup a cluster again until we get more
3593          * space.
3594          */
3595         if (unlikely(last_ptr)) {
3596                 spin_lock(&last_ptr->lock);
3597                 last_ptr->fragmented = 1;
3598                 spin_unlock(&last_ptr->lock);
3599         }
3600         if (ffe_ctl->cached) {
3601                 struct btrfs_free_space_ctl *free_space_ctl;
3602
3603                 free_space_ctl = bg->free_space_ctl;
3604                 spin_lock(&free_space_ctl->tree_lock);
3605                 if (free_space_ctl->free_space <
3606                     ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
3607                     ffe_ctl->empty_size) {
3608                         ffe_ctl->total_free_space = max_t(u64,
3609                                         ffe_ctl->total_free_space,
3610                                         free_space_ctl->free_space);
3611                         spin_unlock(&free_space_ctl->tree_lock);
3612                         return 1;
3613                 }
3614                 spin_unlock(&free_space_ctl->tree_lock);
3615         }
3616
3617         offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,
3618                         ffe_ctl->num_bytes, ffe_ctl->empty_size,
3619                         &ffe_ctl->max_extent_size);
3620
3621         /*
3622          * If we didn't find a chunk, and we haven't failed on this block group
3623          * before, and this block group is in the middle of caching and we are
3624          * ok with waiting, then go ahead and wait for progress to be made, and
3625          * set @retry_unclustered to true.
3626          *
3627          * If @retry_unclustered is true then we've already waited on this
3628          * block group once and should move on to the next block group.
3629          */
3630         if (!offset && !ffe_ctl->retry_unclustered && !ffe_ctl->cached &&
3631             ffe_ctl->loop > LOOP_CACHING_NOWAIT) {
3632                 btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
3633                                                       ffe_ctl->empty_size);
3634                 ffe_ctl->retry_unclustered = true;
3635                 return -EAGAIN;
3636         } else if (!offset) {
3637                 return 1;
3638         }
3639         ffe_ctl->found_offset = offset;
3640         return 0;
3641 }
3642
3643 static int do_allocation_clustered(struct btrfs_block_group *block_group,
3644                                    struct find_free_extent_ctl *ffe_ctl,
3645                                    struct btrfs_block_group **bg_ret)
3646 {
3647         int ret;
3648
3649         /* We want to try and use the cluster allocator, so lets look there */
3650         if (ffe_ctl->last_ptr && ffe_ctl->use_cluster) {
3651                 ret = find_free_extent_clustered(block_group, ffe_ctl, bg_ret);
3652                 if (ret >= 0 || ret == -EAGAIN)
3653                         return ret;
3654                 /* ret == -ENOENT case falls through */
3655         }
3656
3657         return find_free_extent_unclustered(block_group, ffe_ctl);
3658 }
3659
3660 static int do_allocation(struct btrfs_block_group *block_group,
3661                          struct find_free_extent_ctl *ffe_ctl,
3662                          struct btrfs_block_group **bg_ret)
3663 {
3664         switch (ffe_ctl->policy) {
3665         case BTRFS_EXTENT_ALLOC_CLUSTERED:
3666                 return do_allocation_clustered(block_group, ffe_ctl, bg_ret);
3667         default:
3668                 BUG();
3669         }
3670 }
3671
3672 static void release_block_group(struct btrfs_block_group *block_group,
3673                                 struct find_free_extent_ctl *ffe_ctl,
3674                                 int delalloc)
3675 {
3676         switch (ffe_ctl->policy) {
3677         case BTRFS_EXTENT_ALLOC_CLUSTERED:
3678                 ffe_ctl->retry_clustered = false;
3679                 ffe_ctl->retry_unclustered = false;
3680                 break;
3681         default:
3682                 BUG();
3683         }
3684
3685         BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
3686                ffe_ctl->index);
3687         btrfs_release_block_group(block_group, delalloc);
3688 }
3689
3690 static void found_extent_clustered(struct find_free_extent_ctl *ffe_ctl,
3691                                    struct btrfs_key *ins)
3692 {
3693         struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3694
3695         if (!ffe_ctl->use_cluster && last_ptr) {
3696                 spin_lock(&last_ptr->lock);
3697                 last_ptr->window_start = ins->objectid;
3698                 spin_unlock(&last_ptr->lock);
3699         }
3700 }
3701
3702 static void found_extent(struct find_free_extent_ctl *ffe_ctl,
3703                          struct btrfs_key *ins)
3704 {
3705         switch (ffe_ctl->policy) {
3706         case BTRFS_EXTENT_ALLOC_CLUSTERED:
3707                 found_extent_clustered(ffe_ctl, ins);
3708                 break;
3709         default:
3710                 BUG();
3711         }
3712 }
3713
3714 static int chunk_allocation_failed(struct find_free_extent_ctl *ffe_ctl)
3715 {
3716         switch (ffe_ctl->policy) {
3717         case BTRFS_EXTENT_ALLOC_CLUSTERED:
3718                 /*
3719                  * If we can't allocate a new chunk we've already looped through
3720                  * at least once, move on to the NO_EMPTY_SIZE case.
3721                  */
3722                 ffe_ctl->loop = LOOP_NO_EMPTY_SIZE;
3723                 return 0;
3724         default:
3725                 BUG();
3726         }
3727 }
3728
3729 /*
3730  * Return >0 means caller needs to re-search for free extent
3731  * Return 0 means we have the needed free extent.
3732  * Return <0 means we failed to locate any free extent.
3733  */
3734 static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
3735                                         struct btrfs_key *ins,
3736                                         struct find_free_extent_ctl *ffe_ctl,
3737                                         bool full_search)
3738 {
3739         struct btrfs_root *root = fs_info->extent_root;
3740         int ret;
3741
3742         if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
3743             ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
3744                 ffe_ctl->orig_have_caching_bg = true;
3745
3746         if (!ins->objectid && ffe_ctl->loop >= LOOP_CACHING_WAIT &&
3747             ffe_ctl->have_caching_bg)
3748                 return 1;
3749
3750         if (!ins->objectid && ++(ffe_ctl->index) < BTRFS_NR_RAID_TYPES)
3751                 return 1;
3752
3753         if (ins->objectid) {
3754                 found_extent(ffe_ctl, ins);
3755                 return 0;
3756         }
3757
3758         /*
3759          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
3760          *                      caching kthreads as we move along
3761          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
3762          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
3763          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
3764          *                     again
3765          */
3766         if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
3767                 ffe_ctl->index = 0;
3768                 if (ffe_ctl->loop == LOOP_CACHING_NOWAIT) {
3769                         /*
3770                          * We want to skip the LOOP_CACHING_WAIT step if we
3771                          * don't have any uncached bgs and we've already done a
3772                          * full search through.
3773                          */
3774                         if (ffe_ctl->orig_have_caching_bg || !full_search)
3775                                 ffe_ctl->loop = LOOP_CACHING_WAIT;
3776                         else
3777                                 ffe_ctl->loop = LOOP_ALLOC_CHUNK;
3778                 } else {
3779                         ffe_ctl->loop++;
3780                 }
3781
3782                 if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
3783                         struct btrfs_trans_handle *trans;
3784                         int exist = 0;
3785
3786                         trans = current->journal_info;
3787                         if (trans)
3788                                 exist = 1;
3789                         else
3790                                 trans = btrfs_join_transaction(root);
3791
3792                         if (IS_ERR(trans)) {
3793                                 ret = PTR_ERR(trans);
3794                                 return ret;
3795                         }
3796
3797                         ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,
3798                                                 CHUNK_ALLOC_FORCE);
3799
3800                         /* Do not bail out on ENOSPC since we can do more. */
3801                         if (ret == -ENOSPC)
3802                                 ret = chunk_allocation_failed(ffe_ctl);
3803                         else if (ret < 0)
3804                                 btrfs_abort_transaction(trans, ret);
3805                         else
3806                                 ret = 0;
3807                         if (!exist)
3808                                 btrfs_end_transaction(trans);
3809                         if (ret)
3810                                 return ret;
3811                 }
3812
3813                 if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
3814                         if (ffe_ctl->policy != BTRFS_EXTENT_ALLOC_CLUSTERED)
3815                                 return -ENOSPC;
3816
3817                         /*
3818                          * Don't loop again if we already have no empty_size and
3819                          * no empty_cluster.
3820                          */
3821                         if (ffe_ctl->empty_size == 0 &&
3822                             ffe_ctl->empty_cluster == 0)
3823                                 return -ENOSPC;
3824                         ffe_ctl->empty_size = 0;
3825                         ffe_ctl->empty_cluster = 0;
3826                 }
3827                 return 1;
3828         }
3829         return -ENOSPC;
3830 }
3831
3832 static int prepare_allocation_clustered(struct btrfs_fs_info *fs_info,
3833                                         struct find_free_extent_ctl *ffe_ctl,
3834                                         struct btrfs_space_info *space_info,
3835                                         struct btrfs_key *ins)
3836 {
3837         /*
3838          * If our free space is heavily fragmented we may not be able to make
3839          * big contiguous allocations, so instead of doing the expensive search
3840          * for free space, simply return ENOSPC with our max_extent_size so we
3841          * can go ahead and search for a more manageable chunk.
3842          *
3843          * If our max_extent_size is large enough for our allocation simply
3844          * disable clustering since we will likely not be able to find enough
3845          * space to create a cluster and induce latency trying.
3846          */
3847         if (space_info->max_extent_size) {
3848                 spin_lock(&space_info->lock);
3849                 if (space_info->max_extent_size &&
3850                     ffe_ctl->num_bytes > space_info->max_extent_size) {
3851                         ins->offset = space_info->max_extent_size;
3852                         spin_unlock(&space_info->lock);
3853                         return -ENOSPC;
3854                 } else if (space_info->max_extent_size) {
3855                         ffe_ctl->use_cluster = false;
3856                 }
3857                 spin_unlock(&space_info->lock);
3858         }
3859
3860         ffe_ctl->last_ptr = fetch_cluster_info(fs_info, space_info,
3861                                                &ffe_ctl->empty_cluster);
3862         if (ffe_ctl->last_ptr) {
3863                 struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3864
3865                 spin_lock(&last_ptr->lock);
3866                 if (last_ptr->block_group)
3867                         ffe_ctl->hint_byte = last_ptr->window_start;
3868                 if (last_ptr->fragmented) {
3869                         /*
3870                          * We still set window_start so we can keep track of the
3871                          * last place we found an allocation to try and save
3872                          * some time.
3873                          */
3874                         ffe_ctl->hint_byte = last_ptr->window_start;
3875                         ffe_ctl->use_cluster = false;
3876                 }
3877                 spin_unlock(&last_ptr->lock);
3878         }
3879
3880         return 0;
3881 }
3882
3883 static int prepare_allocation(struct btrfs_fs_info *fs_info,
3884                               struct find_free_extent_ctl *ffe_ctl,
3885                               struct btrfs_space_info *space_info,
3886                               struct btrfs_key *ins)
3887 {
3888         switch (ffe_ctl->policy) {
3889         case BTRFS_EXTENT_ALLOC_CLUSTERED:
3890                 return prepare_allocation_clustered(fs_info, ffe_ctl,
3891                                                     space_info, ins);
3892         default:
3893                 BUG();
3894         }
3895 }
3896
3897 /*
3898  * walks the btree of allocated extents and find a hole of a given size.
3899  * The key ins is changed to record the hole:
3900  * ins->objectid == start position
3901  * ins->flags = BTRFS_EXTENT_ITEM_KEY
3902  * ins->offset == the size of the hole.
3903  * Any available blocks before search_start are skipped.
3904  *
3905  * If there is no suitable free space, we will record the max size of
3906  * the free space extent currently.
3907  *
3908  * The overall logic and call chain:
3909  *
3910  * find_free_extent()
3911  * |- Iterate through all block groups
3912  * |  |- Get a valid block group
3913  * |  |- Try to do clustered allocation in that block group
3914  * |  |- Try to do unclustered allocation in that block group
3915  * |  |- Check if the result is valid
3916  * |  |  |- If valid, then exit
3917  * |  |- Jump to next block group
3918  * |
3919  * |- Push harder to find free extents
3920  *    |- If not found, re-iterate all block groups
3921  */
3922 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
3923                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
3924                                 u64 hint_byte_orig, struct btrfs_key *ins,
3925                                 u64 flags, int delalloc)
3926 {
3927         int ret = 0;
3928         int cache_block_group_error = 0;
3929         struct btrfs_block_group *block_group = NULL;
3930         struct find_free_extent_ctl ffe_ctl = {0};
3931         struct btrfs_space_info *space_info;
3932         bool full_search = false;
3933
3934         WARN_ON(num_bytes < fs_info->sectorsize);
3935
3936         ffe_ctl.num_bytes = num_bytes;
3937         ffe_ctl.empty_size = empty_size;
3938         ffe_ctl.flags = flags;
3939         ffe_ctl.search_start = 0;
3940         ffe_ctl.delalloc = delalloc;
3941         ffe_ctl.index = btrfs_bg_flags_to_raid_index(flags);
3942         ffe_ctl.have_caching_bg = false;
3943         ffe_ctl.orig_have_caching_bg = false;
3944         ffe_ctl.found_offset = 0;
3945         ffe_ctl.hint_byte = hint_byte_orig;
3946         ffe_ctl.policy = BTRFS_EXTENT_ALLOC_CLUSTERED;
3947
3948         /* For clustered allocation */
3949         ffe_ctl.retry_clustered = false;
3950         ffe_ctl.retry_unclustered = false;
3951         ffe_ctl.last_ptr = NULL;
3952         ffe_ctl.use_cluster = true;
3953
3954         ins->type = BTRFS_EXTENT_ITEM_KEY;
3955         ins->objectid = 0;
3956         ins->offset = 0;
3957
3958         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
3959
3960         space_info = btrfs_find_space_info(fs_info, flags);
3961         if (!space_info) {
3962                 btrfs_err(fs_info, "No space info for %llu", flags);
3963                 return -ENOSPC;
3964         }
3965
3966         ret = prepare_allocation(fs_info, &ffe_ctl, space_info, ins);
3967         if (ret < 0)
3968                 return ret;
3969
3970         ffe_ctl.search_start = max(ffe_ctl.search_start,
3971                                    first_logical_byte(fs_info, 0));
3972         ffe_ctl.search_start = max(ffe_ctl.search_start, ffe_ctl.hint_byte);
3973         if (ffe_ctl.search_start == ffe_ctl.hint_byte) {
3974                 block_group = btrfs_lookup_block_group(fs_info,
3975                                                        ffe_ctl.search_start);
3976                 /*
3977                  * we don't want to use the block group if it doesn't match our
3978                  * allocation bits, or if its not cached.
3979                  *
3980                  * However if we are re-searching with an ideal block group
3981                  * picked out then we don't care that the block group is cached.
3982                  */
3983                 if (block_group && block_group_bits(block_group, flags) &&
3984                     block_group->cached != BTRFS_CACHE_NO) {
3985                         down_read(&space_info->groups_sem);
3986                         if (list_empty(&block_group->list) ||
3987                             block_group->ro) {
3988                                 /*
3989                                  * someone is removing this block group,
3990                                  * we can't jump into the have_block_group
3991                                  * target because our list pointers are not
3992                                  * valid
3993                                  */
3994                                 btrfs_put_block_group(block_group);
3995                                 up_read(&space_info->groups_sem);
3996                         } else {
3997                                 ffe_ctl.index = btrfs_bg_flags_to_raid_index(
3998                                                 block_group->flags);
3999                                 btrfs_lock_block_group(block_group, delalloc);
4000                                 goto have_block_group;
4001                         }
4002                 } else if (block_group) {
4003                         btrfs_put_block_group(block_group);
4004                 }
4005         }
4006 search:
4007         ffe_ctl.have_caching_bg = false;
4008         if (ffe_ctl.index == btrfs_bg_flags_to_raid_index(flags) ||
4009             ffe_ctl.index == 0)
4010                 full_search = true;
4011         down_read(&space_info->groups_sem);
4012         list_for_each_entry(block_group,
4013                             &space_info->block_groups[ffe_ctl.index], list) {
4014                 struct btrfs_block_group *bg_ret;
4015
4016                 /* If the block group is read-only, we can skip it entirely. */
4017                 if (unlikely(block_group->ro))
4018                         continue;
4019
4020                 btrfs_grab_block_group(block_group, delalloc);
4021                 ffe_ctl.search_start = block_group->start;
4022
4023                 /*
4024                  * this can happen if we end up cycling through all the
4025                  * raid types, but we want to make sure we only allocate
4026                  * for the proper type.
4027                  */
4028                 if (!block_group_bits(block_group, flags)) {
4029                         u64 extra = BTRFS_BLOCK_GROUP_DUP |
4030                                 BTRFS_BLOCK_GROUP_RAID1_MASK |
4031                                 BTRFS_BLOCK_GROUP_RAID56_MASK |
4032                                 BTRFS_BLOCK_GROUP_RAID10;
4033
4034                         /*
4035                          * if they asked for extra copies and this block group
4036                          * doesn't provide them, bail.  This does allow us to
4037                          * fill raid0 from raid1.
4038                          */
4039                         if ((flags & extra) && !(block_group->flags & extra))
4040                                 goto loop;
4041
4042                         /*
4043                          * This block group has different flags than we want.
4044                          * It's possible that we have MIXED_GROUP flag but no
4045                          * block group is mixed.  Just skip such block group.
4046                          */
4047                         btrfs_release_block_group(block_group, delalloc);
4048                         continue;
4049                 }
4050
4051 have_block_group:
4052                 ffe_ctl.cached = btrfs_block_group_done(block_group);
4053                 if (unlikely(!ffe_ctl.cached)) {
4054                         ffe_ctl.have_caching_bg = true;
4055                         ret = btrfs_cache_block_group(block_group, 0);
4056
4057                         /*
4058                          * If we get ENOMEM here or something else we want to
4059                          * try other block groups, because it may not be fatal.
4060                          * However if we can't find anything else we need to
4061                          * save our return here so that we return the actual
4062                          * error that caused problems, not ENOSPC.
4063                          */
4064                         if (ret < 0) {
4065                                 if (!cache_block_group_error)
4066                                         cache_block_group_error = ret;
4067                                 ret = 0;
4068                                 goto loop;
4069                         }
4070                         ret = 0;
4071                 }
4072
4073                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
4074                         goto loop;
4075
4076                 bg_ret = NULL;
4077                 ret = do_allocation(block_group, &ffe_ctl, &bg_ret);
4078                 if (ret == 0) {
4079                         if (bg_ret && bg_ret != block_group) {
4080                                 btrfs_release_block_group(block_group, delalloc);
4081                                 block_group = bg_ret;
4082                         }
4083                 } else if (ret == -EAGAIN) {
4084                         goto have_block_group;
4085                 } else if (ret > 0) {
4086                         goto loop;
4087                 }
4088
4089                 /* Checks */
4090                 ffe_ctl.search_start = round_up(ffe_ctl.found_offset,
4091                                              fs_info->stripesize);
4092
4093                 /* move on to the next group */
4094                 if (ffe_ctl.search_start + num_bytes >
4095                     block_group->start + block_group->length) {
4096                         btrfs_add_free_space(block_group, ffe_ctl.found_offset,
4097                                              num_bytes);
4098                         goto loop;
4099                 }
4100
4101                 if (ffe_ctl.found_offset < ffe_ctl.search_start)
4102                         btrfs_add_free_space(block_group, ffe_ctl.found_offset,
4103                                 ffe_ctl.search_start - ffe_ctl.found_offset);
4104
4105                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
4106                                 num_bytes, delalloc);
4107                 if (ret == -EAGAIN) {
4108                         btrfs_add_free_space(block_group, ffe_ctl.found_offset,
4109                                              num_bytes);
4110                         goto loop;
4111                 }
4112                 btrfs_inc_block_group_reservations(block_group);
4113
4114                 /* we are all good, lets return */
4115                 ins->objectid = ffe_ctl.search_start;
4116                 ins->offset = num_bytes;
4117
4118                 trace_btrfs_reserve_extent(block_group, ffe_ctl.search_start,
4119                                            num_bytes);
4120                 btrfs_release_block_group(block_group, delalloc);
4121                 break;
4122 loop:
4123                 release_block_group(block_group, &ffe_ctl, delalloc);
4124                 cond_resched();
4125         }
4126         up_read(&space_info->groups_sem);
4127
4128         ret = find_free_extent_update_loop(fs_info, ins, &ffe_ctl, full_search);
4129         if (ret > 0)
4130                 goto search;
4131
4132         if (ret == -ENOSPC && !cache_block_group_error) {
4133                 /*
4134                  * Use ffe_ctl->total_free_space as fallback if we can't find
4135                  * any contiguous hole.
4136                  */
4137                 if (!ffe_ctl.max_extent_size)
4138                         ffe_ctl.max_extent_size = ffe_ctl.total_free_space;
4139                 spin_lock(&space_info->lock);
4140                 space_info->max_extent_size = ffe_ctl.max_extent_size;
4141                 spin_unlock(&space_info->lock);
4142                 ins->offset = ffe_ctl.max_extent_size;
4143         } else if (ret == -ENOSPC) {
4144                 ret = cache_block_group_error;
4145         }
4146         return ret;
4147 }
4148
4149 /*
4150  * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
4151  *                        hole that is at least as big as @num_bytes.
4152  *
4153  * @root           -    The root that will contain this extent
4154  *
4155  * @ram_bytes      -    The amount of space in ram that @num_bytes take. This
4156  *                      is used for accounting purposes. This value differs
4157  *                      from @num_bytes only in the case of compressed extents.
4158  *
4159  * @num_bytes      -    Number of bytes to allocate on-disk.
4160  *
4161  * @min_alloc_size -    Indicates the minimum amount of space that the
4162  *                      allocator should try to satisfy. In some cases
4163  *                      @num_bytes may be larger than what is required and if
4164  *                      the filesystem is fragmented then allocation fails.
4165  *                      However, the presence of @min_alloc_size gives a
4166  *                      chance to try and satisfy the smaller allocation.
4167  *
4168  * @empty_size     -    A hint that you plan on doing more COW. This is the
4169  *                      size in bytes the allocator should try to find free
4170  *                      next to the block it returns.  This is just a hint and
4171  *                      may be ignored by the allocator.
4172  *
4173  * @hint_byte      -    Hint to the allocator to start searching above the byte
4174  *                      address passed. It might be ignored.
4175  *
4176  * @ins            -    This key is modified to record the found hole. It will
4177  *                      have the following values:
4178  *                      ins->objectid == start position
4179  *                      ins->flags = BTRFS_EXTENT_ITEM_KEY
4180  *                      ins->offset == the size of the hole.
4181  *
4182  * @is_data        -    Boolean flag indicating whether an extent is
4183  *                      allocated for data (true) or metadata (false)
4184  *
4185  * @delalloc       -    Boolean flag indicating whether this allocation is for
4186  *                      delalloc or not. If 'true' data_rwsem of block groups
4187  *                      is going to be acquired.
4188  *
4189  *
4190  * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
4191  * case -ENOSPC is returned then @ins->offset will contain the size of the
4192  * largest available hole the allocator managed to find.
4193  */
4194 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
4195                          u64 num_bytes, u64 min_alloc_size,
4196                          u64 empty_size, u64 hint_byte,
4197                          struct btrfs_key *ins, int is_data, int delalloc)
4198 {
4199         struct btrfs_fs_info *fs_info = root->fs_info;
4200         bool final_tried = num_bytes == min_alloc_size;
4201         u64 flags;
4202         int ret;
4203
4204         flags = get_alloc_profile_by_root(root, is_data);
4205 again:
4206         WARN_ON(num_bytes < fs_info->sectorsize);
4207         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
4208                                hint_byte, ins, flags, delalloc);
4209         if (!ret && !is_data) {
4210                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
4211         } else if (ret == -ENOSPC) {
4212                 if (!final_tried && ins->offset) {
4213                         num_bytes = min(num_bytes >> 1, ins->offset);
4214                         num_bytes = round_down(num_bytes,
4215                                                fs_info->sectorsize);
4216                         num_bytes = max(num_bytes, min_alloc_size);
4217                         ram_bytes = num_bytes;
4218                         if (num_bytes == min_alloc_size)
4219                                 final_tried = true;
4220                         goto again;
4221                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4222                         struct btrfs_space_info *sinfo;
4223
4224                         sinfo = btrfs_find_space_info(fs_info, flags);
4225                         btrfs_err(fs_info,
4226                                   "allocation failed flags %llu, wanted %llu",
4227                                   flags, num_bytes);
4228                         if (sinfo)
4229                                 btrfs_dump_space_info(fs_info, sinfo,
4230                                                       num_bytes, 1);
4231                 }
4232         }
4233
4234         return ret;
4235 }
4236
4237 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
4238                                u64 start, u64 len, int delalloc)
4239 {
4240         struct btrfs_block_group *cache;
4241
4242         cache = btrfs_lookup_block_group(fs_info, start);
4243         if (!cache) {
4244                 btrfs_err(fs_info, "Unable to find block group for %llu",
4245                           start);
4246                 return -ENOSPC;
4247         }
4248
4249         btrfs_add_free_space(cache, start, len);
4250         btrfs_free_reserved_bytes(cache, len, delalloc);
4251         trace_btrfs_reserved_extent_free(fs_info, start, len);
4252
4253         btrfs_put_block_group(cache);
4254         return 0;
4255 }
4256
4257 int btrfs_pin_reserved_extent(struct btrfs_trans_handle *trans, u64 start,
4258                               u64 len)
4259 {
4260         struct btrfs_block_group *cache;
4261         int ret = 0;
4262
4263         cache = btrfs_lookup_block_group(trans->fs_info, start);
4264         if (!cache) {
4265                 btrfs_err(trans->fs_info, "unable to find block group for %llu",
4266                           start);
4267                 return -ENOSPC;
4268         }
4269
4270         ret = pin_down_extent(trans, cache, start, len, 1);
4271         btrfs_put_block_group(cache);
4272         return ret;
4273 }
4274
4275 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4276                                       u64 parent, u64 root_objectid,
4277                                       u64 flags, u64 owner, u64 offset,
4278                                       struct btrfs_key *ins, int ref_mod)
4279 {
4280         struct btrfs_fs_info *fs_info = trans->fs_info;
4281         int ret;
4282         struct btrfs_extent_item *extent_item;
4283         struct btrfs_extent_inline_ref *iref;
4284         struct btrfs_path *path;
4285         struct extent_buffer *leaf;
4286         int type;
4287         u32 size;
4288
4289         if (parent > 0)
4290                 type = BTRFS_SHARED_DATA_REF_KEY;
4291         else
4292                 type = BTRFS_EXTENT_DATA_REF_KEY;
4293
4294         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
4295
4296         path = btrfs_alloc_path();
4297         if (!path)
4298                 return -ENOMEM;
4299
4300         path->leave_spinning = 1;
4301         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
4302                                       ins, size);
4303         if (ret) {
4304                 btrfs_free_path(path);
4305                 return ret;
4306         }
4307
4308         leaf = path->nodes[0];
4309         extent_item = btrfs_item_ptr(leaf, path->slots[0],
4310                                      struct btrfs_extent_item);
4311         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
4312         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4313         btrfs_set_extent_flags(leaf, extent_item,
4314                                flags | BTRFS_EXTENT_FLAG_DATA);
4315
4316         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4317         btrfs_set_extent_inline_ref_type(leaf, iref, type);
4318         if (parent > 0) {
4319                 struct btrfs_shared_data_ref *ref;
4320                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
4321                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
4322                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
4323         } else {
4324                 struct btrfs_extent_data_ref *ref;
4325                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
4326                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
4327                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
4328                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
4329                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
4330         }
4331
4332         btrfs_mark_buffer_dirty(path->nodes[0]);
4333         btrfs_free_path(path);
4334
4335         ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
4336         if (ret)
4337                 return ret;
4338
4339         ret = btrfs_update_block_group(trans, ins->objectid, ins->offset, 1);
4340         if (ret) { /* -ENOENT, logic error */
4341                 btrfs_err(fs_info, "update block group failed for %llu %llu",
4342                         ins->objectid, ins->offset);
4343                 BUG();
4344         }
4345         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
4346         return ret;
4347 }
4348
4349 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
4350                                      struct btrfs_delayed_ref_node *node,
4351                                      struct btrfs_delayed_extent_op *extent_op)
4352 {
4353         struct btrfs_fs_info *fs_info = trans->fs_info;
4354         int ret;
4355         struct btrfs_extent_item *extent_item;
4356         struct btrfs_key extent_key;
4357         struct btrfs_tree_block_info *block_info;
4358         struct btrfs_extent_inline_ref *iref;
4359         struct btrfs_path *path;
4360         struct extent_buffer *leaf;
4361         struct btrfs_delayed_tree_ref *ref;
4362         u32 size = sizeof(*extent_item) + sizeof(*iref);
4363         u64 num_bytes;
4364         u64 flags = extent_op->flags_to_set;
4365         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
4366
4367         ref = btrfs_delayed_node_to_tree_ref(node);
4368
4369         extent_key.objectid = node->bytenr;
4370         if (skinny_metadata) {
4371                 extent_key.offset = ref->level;
4372                 extent_key.type = BTRFS_METADATA_ITEM_KEY;
4373                 num_bytes = fs_info->nodesize;
4374         } else {
4375                 extent_key.offset = node->num_bytes;
4376                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
4377                 size += sizeof(*block_info);
4378                 num_bytes = node->num_bytes;
4379         }
4380
4381         path = btrfs_alloc_path();
4382         if (!path)
4383                 return -ENOMEM;
4384
4385         path->leave_spinning = 1;
4386         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
4387                                       &extent_key, size);
4388         if (ret) {
4389                 btrfs_free_path(path);
4390                 return ret;
4391         }
4392
4393         leaf = path->nodes[0];
4394         extent_item = btrfs_item_ptr(leaf, path->slots[0],
4395                                      struct btrfs_extent_item);
4396         btrfs_set_extent_refs(leaf, extent_item, 1);
4397         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4398         btrfs_set_extent_flags(leaf, extent_item,
4399                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
4400
4401         if (skinny_metadata) {
4402                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4403         } else {
4404                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
4405                 btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
4406                 btrfs_set_tree_block_level(leaf, block_info, ref->level);
4407                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
4408         }
4409
4410         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
4411                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
4412                 btrfs_set_extent_inline_ref_type(leaf, iref,
4413                                                  BTRFS_SHARED_BLOCK_REF_KEY);
4414                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
4415         } else {
4416                 btrfs_set_extent_inline_ref_type(leaf, iref,
4417                                                  BTRFS_TREE_BLOCK_REF_KEY);
4418                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
4419         }
4420
4421         btrfs_mark_buffer_dirty(leaf);
4422         btrfs_free_path(path);
4423
4424         ret = remove_from_free_space_tree(trans, extent_key.objectid,
4425                                           num_bytes);
4426         if (ret)
4427                 return ret;
4428
4429         ret = btrfs_update_block_group(trans, extent_key.objectid,
4430                                        fs_info->nodesize, 1);
4431         if (ret) { /* -ENOENT, logic error */
4432                 btrfs_err(fs_info, "update block group failed for %llu %llu",
4433                         extent_key.objectid, extent_key.offset);
4434                 BUG();
4435         }
4436
4437         trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
4438                                           fs_info->nodesize);
4439         return ret;
4440 }
4441
4442 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4443                                      struct btrfs_root *root, u64 owner,
4444                                      u64 offset, u64 ram_bytes,
4445                                      struct btrfs_key *ins)
4446 {
4447         struct btrfs_ref generic_ref = { 0 };
4448         int ret;
4449
4450         BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
4451
4452         btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
4453                                ins->objectid, ins->offset, 0);
4454         btrfs_init_data_ref(&generic_ref, root->root_key.objectid, owner, offset);
4455         btrfs_ref_tree_mod(root->fs_info, &generic_ref);
4456         ret = btrfs_add_delayed_data_ref(trans, &generic_ref,
4457                                          ram_bytes, NULL, NULL);
4458         return ret;
4459 }
4460
4461 /*
4462  * this is used by the tree logging recovery code.  It records that
4463  * an extent has been allocated and makes sure to clear the free
4464  * space cache bits as well
4465  */
4466 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
4467                                    u64 root_objectid, u64 owner, u64 offset,
4468                                    struct btrfs_key *ins)
4469 {
4470         struct btrfs_fs_info *fs_info = trans->fs_info;
4471         int ret;
4472         struct btrfs_block_group *block_group;
4473         struct btrfs_space_info *space_info;
4474
4475         /*
4476          * Mixed block groups will exclude before processing the log so we only
4477          * need to do the exclude dance if this fs isn't mixed.
4478          */
4479         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
4480                 ret = __exclude_logged_extent(fs_info, ins->objectid,
4481                                               ins->offset);
4482                 if (ret)
4483                         return ret;
4484         }
4485
4486         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
4487         if (!block_group)
4488                 return -EINVAL;
4489
4490         space_info = block_group->space_info;
4491         spin_lock(&space_info->lock);
4492         spin_lock(&block_group->lock);
4493         space_info->bytes_reserved += ins->offset;
4494         block_group->reserved += ins->offset;
4495         spin_unlock(&block_group->lock);
4496         spin_unlock(&space_info->lock);
4497
4498         ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
4499                                          offset, ins, 1);
4500         if (ret)
4501                 btrfs_pin_extent(trans, ins->objectid, ins->offset, 1);
4502         btrfs_put_block_group(block_group);
4503         return ret;
4504 }
4505
4506 static struct extent_buffer *
4507 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4508                       u64 bytenr, int level, u64 owner)
4509 {
4510         struct btrfs_fs_info *fs_info = root->fs_info;
4511         struct extent_buffer *buf;
4512
4513         buf = btrfs_find_create_tree_block(fs_info, bytenr);
4514         if (IS_ERR(buf))
4515                 return buf;
4516
4517         /*
4518          * Extra safety check in case the extent tree is corrupted and extent
4519          * allocator chooses to use a tree block which is already used and
4520          * locked.
4521          */
4522         if (buf->lock_owner == current->pid) {
4523                 btrfs_err_rl(fs_info,
4524 "tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
4525                         buf->start, btrfs_header_owner(buf), current->pid);
4526                 free_extent_buffer(buf);
4527                 return ERR_PTR(-EUCLEAN);
4528         }
4529
4530         btrfs_set_buffer_lockdep_class(owner, buf, level);
4531         btrfs_tree_lock(buf);
4532         btrfs_clean_tree_block(buf);
4533         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
4534
4535         btrfs_set_lock_blocking_write(buf);
4536         set_extent_buffer_uptodate(buf);
4537
4538         memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
4539         btrfs_set_header_level(buf, level);
4540         btrfs_set_header_bytenr(buf, buf->start);
4541         btrfs_set_header_generation(buf, trans->transid);
4542         btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
4543         btrfs_set_header_owner(buf, owner);
4544         write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid);
4545         write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
4546         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
4547                 buf->log_index = root->log_transid % 2;
4548                 /*
4549                  * we allow two log transactions at a time, use different
4550                  * EXTENT bit to differentiate dirty pages.
4551                  */
4552                 if (buf->log_index == 0)
4553                         set_extent_dirty(&root->dirty_log_pages, buf->start,
4554                                         buf->start + buf->len - 1, GFP_NOFS);
4555                 else
4556                         set_extent_new(&root->dirty_log_pages, buf->start,
4557                                         buf->start + buf->len - 1);
4558         } else {
4559                 buf->log_index = -1;
4560                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
4561                          buf->start + buf->len - 1, GFP_NOFS);
4562         }
4563         trans->dirty = true;
4564         /* this returns a buffer locked for blocking */
4565         return buf;
4566 }
4567
4568 /*
4569  * finds a free extent and does all the dirty work required for allocation
4570  * returns the tree buffer or an ERR_PTR on error.
4571  */
4572 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
4573                                              struct btrfs_root *root,
4574                                              u64 parent, u64 root_objectid,
4575                                              const struct btrfs_disk_key *key,
4576                                              int level, u64 hint,
4577                                              u64 empty_size)
4578 {
4579         struct btrfs_fs_info *fs_info = root->fs_info;
4580         struct btrfs_key ins;
4581         struct btrfs_block_rsv *block_rsv;
4582         struct extent_buffer *buf;
4583         struct btrfs_delayed_extent_op *extent_op;
4584         struct btrfs_ref generic_ref = { 0 };
4585         u64 flags = 0;
4586         int ret;
4587         u32 blocksize = fs_info->nodesize;
4588         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
4589
4590 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4591         if (btrfs_is_testing(fs_info)) {
4592                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
4593                                             level, root_objectid);
4594                 if (!IS_ERR(buf))
4595                         root->alloc_bytenr += blocksize;
4596                 return buf;
4597         }
4598 #endif
4599
4600         block_rsv = btrfs_use_block_rsv(trans, root, blocksize);
4601         if (IS_ERR(block_rsv))
4602                 return ERR_CAST(block_rsv);
4603
4604         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
4605                                    empty_size, hint, &ins, 0, 0);
4606         if (ret)
4607                 goto out_unuse;
4608
4609         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
4610                                     root_objectid);
4611         if (IS_ERR(buf)) {
4612                 ret = PTR_ERR(buf);
4613                 goto out_free_reserved;
4614         }
4615
4616         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
4617                 if (parent == 0)
4618                         parent = ins.objectid;
4619                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
4620         } else
4621                 BUG_ON(parent > 0);
4622
4623         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
4624                 extent_op = btrfs_alloc_delayed_extent_op();
4625                 if (!extent_op) {
4626                         ret = -ENOMEM;
4627                         goto out_free_buf;
4628                 }
4629                 if (key)
4630                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
4631                 else
4632                         memset(&extent_op->key, 0, sizeof(extent_op->key));
4633                 extent_op->flags_to_set = flags;
4634                 extent_op->update_key = skinny_metadata ? false : true;
4635                 extent_op->update_flags = true;
4636                 extent_op->is_data = false;
4637                 extent_op->level = level;
4638
4639                 btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
4640                                        ins.objectid, ins.offset, parent);
4641                 generic_ref.real_root = root->root_key.objectid;
4642                 btrfs_init_tree_ref(&generic_ref, level, root_objectid);
4643                 btrfs_ref_tree_mod(fs_info, &generic_ref);
4644                 ret = btrfs_add_delayed_tree_ref(trans, &generic_ref,
4645                                                  extent_op, NULL, NULL);
4646                 if (ret)
4647                         goto out_free_delayed;
4648         }
4649         return buf;
4650
4651 out_free_delayed:
4652         btrfs_free_delayed_extent_op(extent_op);
4653 out_free_buf:
4654         free_extent_buffer(buf);
4655 out_free_reserved:
4656         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
4657 out_unuse:
4658         btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);
4659         return ERR_PTR(ret);
4660 }
4661
4662 struct walk_control {
4663         u64 refs[BTRFS_MAX_LEVEL];
4664         u64 flags[BTRFS_MAX_LEVEL];
4665         struct btrfs_key update_progress;
4666         struct btrfs_key drop_progress;
4667         int drop_level;
4668         int stage;
4669         int level;
4670         int shared_level;
4671         int update_ref;
4672         int keep_locks;
4673         int reada_slot;
4674         int reada_count;
4675         int restarted;
4676 };
4677
4678 #define DROP_REFERENCE  1
4679 #define UPDATE_BACKREF  2
4680
4681 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
4682                                      struct btrfs_root *root,
4683                                      struct walk_control *wc,
4684                                      struct btrfs_path *path)
4685 {
4686         struct btrfs_fs_info *fs_info = root->fs_info;
4687         u64 bytenr;
4688         u64 generation;
4689         u64 refs;
4690         u64 flags;
4691         u32 nritems;
4692         struct btrfs_key key;
4693         struct extent_buffer *eb;
4694         int ret;
4695         int slot;
4696         int nread = 0;
4697
4698         if (path->slots[wc->level] < wc->reada_slot) {
4699                 wc->reada_count = wc->reada_count * 2 / 3;
4700                 wc->reada_count = max(wc->reada_count, 2);
4701         } else {
4702                 wc->reada_count = wc->reada_count * 3 / 2;
4703                 wc->reada_count = min_t(int, wc->reada_count,
4704                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
4705         }
4706
4707         eb = path->nodes[wc->level];
4708         nritems = btrfs_header_nritems(eb);
4709
4710         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
4711                 if (nread >= wc->reada_count)
4712                         break;
4713
4714                 cond_resched();
4715                 bytenr = btrfs_node_blockptr(eb, slot);
4716                 generation = btrfs_node_ptr_generation(eb, slot);
4717
4718                 if (slot == path->slots[wc->level])
4719                         goto reada;
4720
4721                 if (wc->stage == UPDATE_BACKREF &&
4722                     generation <= root->root_key.offset)
4723                         continue;
4724
4725                 /* We don't lock the tree block, it's OK to be racy here */
4726                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
4727                                                wc->level - 1, 1, &refs,
4728                                                &flags);
4729                 /* We don't care about errors in readahead. */
4730                 if (ret < 0)
4731                         continue;
4732                 BUG_ON(refs == 0);
4733
4734                 if (wc->stage == DROP_REFERENCE) {
4735                         if (refs == 1)
4736                                 goto reada;
4737
4738                         if (wc->level == 1 &&
4739                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
4740                                 continue;
4741                         if (!wc->update_ref ||
4742                             generation <= root->root_key.offset)
4743                                 continue;
4744                         btrfs_node_key_to_cpu(eb, &key, slot);
4745                         ret = btrfs_comp_cpu_keys(&key,
4746                                                   &wc->update_progress);
4747                         if (ret < 0)
4748                                 continue;
4749                 } else {
4750                         if (wc->level == 1 &&
4751                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
4752                                 continue;
4753                 }
4754 reada:
4755                 readahead_tree_block(fs_info, bytenr);
4756                 nread++;
4757         }
4758         wc->reada_slot = slot;
4759 }
4760
4761 /*
4762  * helper to process tree block while walking down the tree.
4763  *
4764  * when wc->stage == UPDATE_BACKREF, this function updates
4765  * back refs for pointers in the block.
4766  *
4767  * NOTE: return value 1 means we should stop walking down.
4768  */
4769 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
4770                                    struct btrfs_root *root,
4771                                    struct btrfs_path *path,
4772                                    struct walk_control *wc, int lookup_info)
4773 {
4774         struct btrfs_fs_info *fs_info = root->fs_info;
4775         int level = wc->level;
4776         struct extent_buffer *eb = path->nodes[level];
4777         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
4778         int ret;
4779
4780         if (wc->stage == UPDATE_BACKREF &&
4781             btrfs_header_owner(eb) != root->root_key.objectid)
4782                 return 1;
4783
4784         /*
4785          * when reference count of tree block is 1, it won't increase
4786          * again. once full backref flag is set, we never clear it.
4787          */
4788         if (lookup_info &&
4789             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
4790              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
4791                 BUG_ON(!path->locks[level]);
4792                 ret = btrfs_lookup_extent_info(trans, fs_info,
4793                                                eb->start, level, 1,
4794                                                &wc->refs[level],
4795                                                &wc->flags[level]);
4796                 BUG_ON(ret == -ENOMEM);
4797                 if (ret)
4798                         return ret;
4799                 BUG_ON(wc->refs[level] == 0);
4800         }
4801
4802         if (wc->stage == DROP_REFERENCE) {
4803                 if (wc->refs[level] > 1)
4804                         return 1;
4805
4806                 if (path->locks[level] && !wc->keep_locks) {
4807                         btrfs_tree_unlock_rw(eb, path->locks[level]);
4808                         path->locks[level] = 0;
4809                 }
4810                 return 0;
4811         }
4812
4813         /* wc->stage == UPDATE_BACKREF */
4814         if (!(wc->flags[level] & flag)) {
4815                 BUG_ON(!path->locks[level]);
4816                 ret = btrfs_inc_ref(trans, root, eb, 1);
4817                 BUG_ON(ret); /* -ENOMEM */
4818                 ret = btrfs_dec_ref(trans, root, eb, 0);
4819                 BUG_ON(ret); /* -ENOMEM */
4820                 ret = btrfs_set_disk_extent_flags(trans, eb, flag,
4821                                                   btrfs_header_level(eb), 0);
4822                 BUG_ON(ret); /* -ENOMEM */
4823                 wc->flags[level] |= flag;
4824         }
4825
4826         /*
4827          * the block is shared by multiple trees, so it's not good to
4828          * keep the tree lock
4829          */
4830         if (path->locks[level] && level > 0) {
4831                 btrfs_tree_unlock_rw(eb, path->locks[level]);
4832                 path->locks[level] = 0;
4833         }
4834         return 0;
4835 }
4836
4837 /*
4838  * This is used to verify a ref exists for this root to deal with a bug where we
4839  * would have a drop_progress key that hadn't been updated properly.
4840  */
4841 static int check_ref_exists(struct btrfs_trans_handle *trans,
4842                             struct btrfs_root *root, u64 bytenr, u64 parent,
4843                             int level)
4844 {
4845         struct btrfs_path *path;
4846         struct btrfs_extent_inline_ref *iref;
4847         int ret;
4848
4849         path = btrfs_alloc_path();
4850         if (!path)
4851                 return -ENOMEM;
4852
4853         ret = lookup_extent_backref(trans, path, &iref, bytenr,
4854                                     root->fs_info->nodesize, parent,
4855                                     root->root_key.objectid, level, 0);
4856         btrfs_free_path(path);
4857         if (ret == -ENOENT)
4858                 return 0;
4859         if (ret < 0)
4860                 return ret;
4861         return 1;
4862 }
4863
4864 /*
4865  * helper to process tree block pointer.
4866  *
4867  * when wc->stage == DROP_REFERENCE, this function checks
4868  * reference count of the block pointed to. if the block
4869  * is shared and we need update back refs for the subtree
4870  * rooted at the block, this function changes wc->stage to
4871  * UPDATE_BACKREF. if the block is shared and there is no
4872  * need to update back, this function drops the reference
4873  * to the block.
4874  *
4875  * NOTE: return value 1 means we should stop walking down.
4876  */
4877 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
4878                                  struct btrfs_root *root,
4879                                  struct btrfs_path *path,
4880                                  struct walk_control *wc, int *lookup_info)
4881 {
4882         struct btrfs_fs_info *fs_info = root->fs_info;
4883         u64 bytenr;
4884         u64 generation;
4885         u64 parent;
4886         struct btrfs_key key;
4887         struct btrfs_key first_key;
4888         struct btrfs_ref ref = { 0 };
4889         struct extent_buffer *next;
4890         int level = wc->level;
4891         int reada = 0;
4892         int ret = 0;
4893         bool need_account = false;
4894
4895         generation = btrfs_node_ptr_generation(path->nodes[level],
4896                                                path->slots[level]);
4897         /*
4898          * if the lower level block was created before the snapshot
4899          * was created, we know there is no need to update back refs
4900          * for the subtree
4901          */
4902         if (wc->stage == UPDATE_BACKREF &&
4903             generation <= root->root_key.offset) {
4904                 *lookup_info = 1;
4905                 return 1;
4906         }
4907
4908         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
4909         btrfs_node_key_to_cpu(path->nodes[level], &first_key,
4910                               path->slots[level]);
4911
4912         next = find_extent_buffer(fs_info, bytenr);
4913         if (!next) {
4914                 next = btrfs_find_create_tree_block(fs_info, bytenr);
4915                 if (IS_ERR(next))
4916                         return PTR_ERR(next);
4917
4918                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
4919                                                level - 1);
4920                 reada = 1;
4921         }
4922         btrfs_tree_lock(next);
4923         btrfs_set_lock_blocking_write(next);
4924
4925         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
4926                                        &wc->refs[level - 1],
4927                                        &wc->flags[level - 1]);
4928         if (ret < 0)
4929                 goto out_unlock;
4930
4931         if (unlikely(wc->refs[level - 1] == 0)) {
4932                 btrfs_err(fs_info, "Missing references.");
4933                 ret = -EIO;
4934                 goto out_unlock;
4935         }
4936         *lookup_info = 0;
4937
4938         if (wc->stage == DROP_REFERENCE) {
4939                 if (wc->refs[level - 1] > 1) {
4940                         need_account = true;
4941                         if (level == 1 &&
4942                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
4943                                 goto skip;
4944
4945                         if (!wc->update_ref ||
4946                             generation <= root->root_key.offset)
4947                                 goto skip;
4948
4949                         btrfs_node_key_to_cpu(path->nodes[level], &key,
4950                                               path->slots[level]);
4951                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
4952                         if (ret < 0)
4953                                 goto skip;
4954
4955                         wc->stage = UPDATE_BACKREF;
4956                         wc->shared_level = level - 1;
4957                 }
4958         } else {
4959                 if (level == 1 &&
4960                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
4961                         goto skip;
4962         }
4963
4964         if (!btrfs_buffer_uptodate(next, generation, 0)) {
4965                 btrfs_tree_unlock(next);
4966                 free_extent_buffer(next);
4967                 next = NULL;
4968                 *lookup_info = 1;
4969         }
4970
4971         if (!next) {
4972                 if (reada && level == 1)
4973                         reada_walk_down(trans, root, wc, path);
4974                 next = read_tree_block(fs_info, bytenr, generation, level - 1,
4975                                        &first_key);
4976                 if (IS_ERR(next)) {
4977                         return PTR_ERR(next);
4978                 } else if (!extent_buffer_uptodate(next)) {
4979                         free_extent_buffer(next);
4980                         return -EIO;
4981                 }
4982                 btrfs_tree_lock(next);
4983                 btrfs_set_lock_blocking_write(next);
4984         }
4985
4986         level--;
4987         ASSERT(level == btrfs_header_level(next));
4988         if (level != btrfs_header_level(next)) {
4989                 btrfs_err(root->fs_info, "mismatched level");
4990                 ret = -EIO;
4991                 goto out_unlock;
4992         }
4993         path->nodes[level] = next;
4994         path->slots[level] = 0;
4995         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
4996         wc->level = level;
4997         if (wc->level == 1)
4998                 wc->reada_slot = 0;
4999         return 0;
5000 skip:
5001         wc->refs[level - 1] = 0;
5002         wc->flags[level - 1] = 0;
5003         if (wc->stage == DROP_REFERENCE) {
5004                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
5005                         parent = path->nodes[level]->start;
5006                 } else {
5007                         ASSERT(root->root_key.objectid ==
5008                                btrfs_header_owner(path->nodes[level]));
5009                         if (root->root_key.objectid !=
5010                             btrfs_header_owner(path->nodes[level])) {
5011                                 btrfs_err(root->fs_info,
5012                                                 "mismatched block owner");
5013                                 ret = -EIO;
5014                                 goto out_unlock;
5015                         }
5016                         parent = 0;
5017                 }
5018
5019                 /*
5020                  * If we had a drop_progress we need to verify the refs are set
5021                  * as expected.  If we find our ref then we know that from here
5022                  * on out everything should be correct, and we can clear the
5023                  * ->restarted flag.
5024                  */
5025                 if (wc->restarted) {
5026                         ret = check_ref_exists(trans, root, bytenr, parent,
5027                                                level - 1);
5028                         if (ret < 0)
5029                                 goto out_unlock;
5030                         if (ret == 0)
5031                                 goto no_delete;
5032                         ret = 0;
5033                         wc->restarted = 0;
5034                 }
5035
5036                 /*
5037                  * Reloc tree doesn't contribute to qgroup numbers, and we have
5038                  * already accounted them at merge time (replace_path),
5039                  * thus we could skip expensive subtree trace here.
5040                  */
5041                 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
5042                     need_account) {
5043                         ret = btrfs_qgroup_trace_subtree(trans, next,
5044                                                          generation, level - 1);
5045                         if (ret) {
5046                                 btrfs_err_rl(fs_info,
5047                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
5048                                              ret);
5049                         }
5050                 }
5051
5052                 /*
5053                  * We need to update the next key in our walk control so we can
5054                  * update the drop_progress key accordingly.  We don't care if
5055                  * find_next_key doesn't find a key because that means we're at
5056                  * the end and are going to clean up now.
5057                  */
5058                 wc->drop_level = level;
5059                 find_next_key(path, level, &wc->drop_progress);
5060
5061                 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
5062                                        fs_info->nodesize, parent);
5063                 btrfs_init_tree_ref(&ref, level - 1, root->root_key.objectid);
5064                 ret = btrfs_free_extent(trans, &ref);
5065                 if (ret)
5066                         goto out_unlock;
5067         }
5068 no_delete:
5069         *lookup_info = 1;
5070         ret = 1;
5071
5072 out_unlock:
5073         btrfs_tree_unlock(next);
5074         free_extent_buffer(next);
5075
5076         return ret;
5077 }
5078
5079 /*
5080  * helper to process tree block while walking up the tree.
5081  *
5082  * when wc->stage == DROP_REFERENCE, this function drops
5083  * reference count on the block.
5084  *
5085  * when wc->stage == UPDATE_BACKREF, this function changes
5086  * wc->stage back to DROP_REFERENCE if we changed wc->stage
5087  * to UPDATE_BACKREF previously while processing the block.
5088  *
5089  * NOTE: return value 1 means we should stop walking up.
5090  */
5091 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
5092                                  struct btrfs_root *root,
5093                                  struct btrfs_path *path,
5094                                  struct walk_control *wc)
5095 {
5096         struct btrfs_fs_info *fs_info = root->fs_info;
5097         int ret;
5098         int level = wc->level;
5099         struct extent_buffer *eb = path->nodes[level];
5100         u64 parent = 0;
5101
5102         if (wc->stage == UPDATE_BACKREF) {
5103                 BUG_ON(wc->shared_level < level);
5104                 if (level < wc->shared_level)
5105                         goto out;
5106
5107                 ret = find_next_key(path, level + 1, &wc->update_progress);
5108                 if (ret > 0)
5109                         wc->update_ref = 0;
5110
5111                 wc->stage = DROP_REFERENCE;
5112                 wc->shared_level = -1;
5113                 path->slots[level] = 0;
5114
5115                 /*
5116                  * check reference count again if the block isn't locked.
5117                  * we should start walking down the tree again if reference
5118                  * count is one.
5119                  */
5120                 if (!path->locks[level]) {
5121                         BUG_ON(level == 0);
5122                         btrfs_tree_lock(eb);
5123                         btrfs_set_lock_blocking_write(eb);
5124                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5125
5126                         ret = btrfs_lookup_extent_info(trans, fs_info,
5127                                                        eb->start, level, 1,
5128                                                        &wc->refs[level],
5129                                                        &wc->flags[level]);
5130                         if (ret < 0) {
5131                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
5132                                 path->locks[level] = 0;
5133                                 return ret;
5134                         }
5135                         BUG_ON(wc->refs[level] == 0);
5136                         if (wc->refs[level] == 1) {
5137                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
5138                                 path->locks[level] = 0;
5139                                 return 1;
5140                         }
5141                 }
5142         }
5143
5144         /* wc->stage == DROP_REFERENCE */
5145         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
5146
5147         if (wc->refs[level] == 1) {
5148                 if (level == 0) {
5149                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5150                                 ret = btrfs_dec_ref(trans, root, eb, 1);
5151                         else
5152                                 ret = btrfs_dec_ref(trans, root, eb, 0);
5153                         BUG_ON(ret); /* -ENOMEM */
5154                         if (is_fstree(root->root_key.objectid)) {
5155                                 ret = btrfs_qgroup_trace_leaf_items(trans, eb);
5156                                 if (ret) {
5157                                         btrfs_err_rl(fs_info,
5158         "error %d accounting leaf items, quota is out of sync, rescan required",
5159                                              ret);
5160                                 }
5161                         }
5162                 }
5163                 /* make block locked assertion in btrfs_clean_tree_block happy */
5164                 if (!path->locks[level] &&
5165                     btrfs_header_generation(eb) == trans->transid) {
5166                         btrfs_tree_lock(eb);
5167                         btrfs_set_lock_blocking_write(eb);
5168                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5169                 }
5170                 btrfs_clean_tree_block(eb);
5171         }
5172
5173         if (eb == root->node) {
5174                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5175                         parent = eb->start;
5176                 else if (root->root_key.objectid != btrfs_header_owner(eb))
5177                         goto owner_mismatch;
5178         } else {
5179                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5180                         parent = path->nodes[level + 1]->start;
5181                 else if (root->root_key.objectid !=
5182                          btrfs_header_owner(path->nodes[level + 1]))
5183                         goto owner_mismatch;
5184         }
5185
5186         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
5187 out:
5188         wc->refs[level] = 0;
5189         wc->flags[level] = 0;
5190         return 0;
5191
5192 owner_mismatch:
5193         btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
5194                      btrfs_header_owner(eb), root->root_key.objectid);
5195         return -EUCLEAN;
5196 }
5197
5198 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
5199                                    struct btrfs_root *root,
5200                                    struct btrfs_path *path,
5201                                    struct walk_control *wc)
5202 {
5203         int level = wc->level;
5204         int lookup_info = 1;
5205         int ret;
5206
5207         while (level >= 0) {
5208                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
5209                 if (ret > 0)
5210                         break;
5211
5212                 if (level == 0)
5213                         break;
5214
5215                 if (path->slots[level] >=
5216                     btrfs_header_nritems(path->nodes[level]))
5217                         break;
5218
5219                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
5220                 if (ret > 0) {
5221                         path->slots[level]++;
5222                         continue;
5223                 } else if (ret < 0)
5224                         return ret;
5225                 level = wc->level;
5226         }
5227         return 0;
5228 }
5229
5230 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
5231                                  struct btrfs_root *root,
5232                                  struct btrfs_path *path,
5233                                  struct walk_control *wc, int max_level)
5234 {
5235         int level = wc->level;
5236         int ret;
5237
5238         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
5239         while (level < max_level && path->nodes[level]) {
5240                 wc->level = level;
5241                 if (path->slots[level] + 1 <
5242                     btrfs_header_nritems(path->nodes[level])) {
5243                         path->slots[level]++;
5244                         return 0;
5245                 } else {
5246                         ret = walk_up_proc(trans, root, path, wc);
5247                         if (ret > 0)
5248                                 return 0;
5249                         if (ret < 0)
5250                                 return ret;
5251
5252                         if (path->locks[level]) {
5253                                 btrfs_tree_unlock_rw(path->nodes[level],
5254                                                      path->locks[level]);
5255                                 path->locks[level] = 0;
5256                         }
5257                         free_extent_buffer(path->nodes[level]);
5258                         path->nodes[level] = NULL;
5259                         level++;
5260                 }
5261         }
5262         return 1;
5263 }
5264
5265 /*
5266  * drop a subvolume tree.
5267  *
5268  * this function traverses the tree freeing any blocks that only
5269  * referenced by the tree.
5270  *
5271  * when a shared tree block is found. this function decreases its
5272  * reference count by one. if update_ref is true, this function
5273  * also make sure backrefs for the shared block and all lower level
5274  * blocks are properly updated.
5275  *
5276  * If called with for_reloc == 0, may exit early with -EAGAIN
5277  */
5278 int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
5279 {
5280         struct btrfs_fs_info *fs_info = root->fs_info;
5281         struct btrfs_path *path;
5282         struct btrfs_trans_handle *trans;
5283         struct btrfs_root *tree_root = fs_info->tree_root;
5284         struct btrfs_root_item *root_item = &root->root_item;
5285         struct walk_control *wc;
5286         struct btrfs_key key;
5287         int err = 0;
5288         int ret;
5289         int level;
5290         bool root_dropped = false;
5291
5292         btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
5293
5294         path = btrfs_alloc_path();
5295         if (!path) {
5296                 err = -ENOMEM;
5297                 goto out;
5298         }
5299
5300         wc = kzalloc(sizeof(*wc), GFP_NOFS);
5301         if (!wc) {
5302                 btrfs_free_path(path);
5303                 err = -ENOMEM;
5304                 goto out;
5305         }
5306
5307         /*
5308          * Use join to avoid potential EINTR from transaction start. See
5309          * wait_reserve_ticket and the whole reservation callchain.
5310          */
5311         if (for_reloc)
5312                 trans = btrfs_join_transaction(tree_root);
5313         else
5314                 trans = btrfs_start_transaction(tree_root, 0);
5315         if (IS_ERR(trans)) {
5316                 err = PTR_ERR(trans);
5317                 goto out_free;
5318         }
5319
5320         err = btrfs_run_delayed_items(trans);
5321         if (err)
5322                 goto out_end_trans;
5323
5324         /*
5325          * This will help us catch people modifying the fs tree while we're
5326          * dropping it.  It is unsafe to mess with the fs tree while it's being
5327          * dropped as we unlock the root node and parent nodes as we walk down
5328          * the tree, assuming nothing will change.  If something does change
5329          * then we'll have stale information and drop references to blocks we've
5330          * already dropped.
5331          */
5332         set_bit(BTRFS_ROOT_DELETING, &root->state);
5333         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
5334                 level = btrfs_header_level(root->node);
5335                 path->nodes[level] = btrfs_lock_root_node(root);
5336                 btrfs_set_lock_blocking_write(path->nodes[level]);
5337                 path->slots[level] = 0;
5338                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5339                 memset(&wc->update_progress, 0,
5340                        sizeof(wc->update_progress));
5341         } else {
5342                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
5343                 memcpy(&wc->update_progress, &key,
5344                        sizeof(wc->update_progress));
5345
5346                 level = root_item->drop_level;
5347                 BUG_ON(level == 0);
5348                 path->lowest_level = level;
5349                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5350                 path->lowest_level = 0;
5351                 if (ret < 0) {
5352                         err = ret;
5353                         goto out_end_trans;
5354                 }
5355                 WARN_ON(ret > 0);
5356
5357                 /*
5358                  * unlock our path, this is safe because only this
5359                  * function is allowed to delete this snapshot
5360                  */
5361                 btrfs_unlock_up_safe(path, 0);
5362
5363                 level = btrfs_header_level(root->node);
5364                 while (1) {
5365                         btrfs_tree_lock(path->nodes[level]);
5366                         btrfs_set_lock_blocking_write(path->nodes[level]);
5367                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5368
5369                         ret = btrfs_lookup_extent_info(trans, fs_info,
5370                                                 path->nodes[level]->start,
5371                                                 level, 1, &wc->refs[level],
5372                                                 &wc->flags[level]);
5373                         if (ret < 0) {
5374                                 err = ret;
5375                                 goto out_end_trans;
5376                         }
5377                         BUG_ON(wc->refs[level] == 0);
5378
5379                         if (level == root_item->drop_level)
5380                                 break;
5381
5382                         btrfs_tree_unlock(path->nodes[level]);
5383                         path->locks[level] = 0;
5384                         WARN_ON(wc->refs[level] != 1);
5385                         level--;
5386                 }
5387         }
5388
5389         wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
5390         wc->level = level;
5391         wc->shared_level = -1;
5392         wc->stage = DROP_REFERENCE;
5393         wc->update_ref = update_ref;
5394         wc->keep_locks = 0;
5395         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
5396
5397         while (1) {
5398
5399                 ret = walk_down_tree(trans, root, path, wc);
5400                 if (ret < 0) {
5401                         err = ret;
5402                         break;
5403                 }
5404
5405                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
5406                 if (ret < 0) {
5407                         err = ret;
5408                         break;
5409                 }
5410
5411                 if (ret > 0) {
5412                         BUG_ON(wc->stage != DROP_REFERENCE);
5413                         break;
5414                 }
5415
5416                 if (wc->stage == DROP_REFERENCE) {
5417                         wc->drop_level = wc->level;
5418                         btrfs_node_key_to_cpu(path->nodes[wc->drop_level],
5419                                               &wc->drop_progress,
5420                                               path->slots[wc->drop_level]);
5421                 }
5422                 btrfs_cpu_key_to_disk(&root_item->drop_progress,
5423                                       &wc->drop_progress);
5424                 root_item->drop_level = wc->drop_level;
5425
5426                 BUG_ON(wc->level == 0);
5427                 if (btrfs_should_end_transaction(trans) ||
5428                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
5429                         ret = btrfs_update_root(trans, tree_root,
5430                                                 &root->root_key,
5431                                                 root_item);
5432                         if (ret) {
5433                                 btrfs_abort_transaction(trans, ret);
5434                                 err = ret;
5435                                 goto out_end_trans;
5436                         }
5437
5438                         btrfs_end_transaction_throttle(trans);
5439                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
5440                                 btrfs_debug(fs_info,
5441                                             "drop snapshot early exit");
5442                                 err = -EAGAIN;
5443                                 goto out_free;
5444                         }
5445
5446                         trans = btrfs_start_transaction(tree_root, 0);
5447                         if (IS_ERR(trans)) {
5448                                 err = PTR_ERR(trans);
5449                                 goto out_free;
5450                         }
5451                 }
5452         }
5453         btrfs_release_path(path);
5454         if (err)
5455                 goto out_end_trans;
5456
5457         ret = btrfs_del_root(trans, &root->root_key);
5458         if (ret) {
5459                 btrfs_abort_transaction(trans, ret);
5460                 err = ret;
5461                 goto out_end_trans;
5462         }
5463
5464         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
5465                 ret = btrfs_find_root(tree_root, &root->root_key, path,
5466                                       NULL, NULL);
5467                 if (ret < 0) {
5468                         btrfs_abort_transaction(trans, ret);
5469                         err = ret;
5470                         goto out_end_trans;
5471                 } else if (ret > 0) {
5472                         /* if we fail to delete the orphan item this time
5473                          * around, it'll get picked up the next time.
5474                          *
5475                          * The most common failure here is just -ENOENT.
5476                          */
5477                         btrfs_del_orphan_item(trans, tree_root,
5478                                               root->root_key.objectid);
5479                 }
5480         }
5481
5482         /*
5483          * This subvolume is going to be completely dropped, and won't be
5484          * recorded as dirty roots, thus pertrans meta rsv will not be freed at
5485          * commit transaction time.  So free it here manually.
5486          */
5487         btrfs_qgroup_convert_reserved_meta(root, INT_MAX);
5488         btrfs_qgroup_free_meta_all_pertrans(root);
5489
5490         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state))
5491                 btrfs_add_dropped_root(trans, root);
5492         else
5493                 btrfs_put_root(root);
5494         root_dropped = true;
5495 out_end_trans:
5496         btrfs_end_transaction_throttle(trans);
5497 out_free:
5498         kfree(wc);
5499         btrfs_free_path(path);
5500 out:
5501         /*
5502          * So if we need to stop dropping the snapshot for whatever reason we
5503          * need to make sure to add it back to the dead root list so that we
5504          * keep trying to do the work later.  This also cleans up roots if we
5505          * don't have it in the radix (like when we recover after a power fail
5506          * or unmount) so we don't leak memory.
5507          */
5508         if (!for_reloc && !root_dropped)
5509                 btrfs_add_dead_root(root);
5510         return err;
5511 }
5512
5513 /*
5514  * drop subtree rooted at tree block 'node'.
5515  *
5516  * NOTE: this function will unlock and release tree block 'node'
5517  * only used by relocation code
5518  */
5519 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
5520                         struct btrfs_root *root,
5521                         struct extent_buffer *node,
5522                         struct extent_buffer *parent)
5523 {
5524         struct btrfs_fs_info *fs_info = root->fs_info;
5525         struct btrfs_path *path;
5526         struct walk_control *wc;
5527         int level;
5528         int parent_level;
5529         int ret = 0;
5530         int wret;
5531
5532         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
5533
5534         path = btrfs_alloc_path();
5535         if (!path)
5536                 return -ENOMEM;
5537
5538         wc = kzalloc(sizeof(*wc), GFP_NOFS);
5539         if (!wc) {
5540                 btrfs_free_path(path);
5541                 return -ENOMEM;
5542         }
5543
5544         btrfs_assert_tree_locked(parent);
5545         parent_level = btrfs_header_level(parent);
5546         atomic_inc(&parent->refs);
5547         path->nodes[parent_level] = parent;
5548         path->slots[parent_level] = btrfs_header_nritems(parent);
5549
5550         btrfs_assert_tree_locked(node);
5551         level = btrfs_header_level(node);
5552         path->nodes[level] = node;
5553         path->slots[level] = 0;
5554         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5555
5556         wc->refs[parent_level] = 1;
5557         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5558         wc->level = level;
5559         wc->shared_level = -1;
5560         wc->stage = DROP_REFERENCE;
5561         wc->update_ref = 0;
5562         wc->keep_locks = 1;
5563         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
5564
5565         while (1) {
5566                 wret = walk_down_tree(trans, root, path, wc);
5567                 if (wret < 0) {
5568                         ret = wret;
5569                         break;
5570                 }
5571
5572                 wret = walk_up_tree(trans, root, path, wc, parent_level);
5573                 if (wret < 0)
5574                         ret = wret;
5575                 if (wret != 0)
5576                         break;
5577         }
5578
5579         kfree(wc);
5580         btrfs_free_path(path);
5581         return ret;
5582 }
5583
5584 /*
5585  * helper to account the unused space of all the readonly block group in the
5586  * space_info. takes mirrors into account.
5587  */
5588 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
5589 {
5590         struct btrfs_block_group *block_group;
5591         u64 free_bytes = 0;
5592         int factor;
5593
5594         /* It's df, we don't care if it's racy */
5595         if (list_empty(&sinfo->ro_bgs))
5596                 return 0;
5597
5598         spin_lock(&sinfo->lock);
5599         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
5600                 spin_lock(&block_group->lock);
5601
5602                 if (!block_group->ro) {
5603                         spin_unlock(&block_group->lock);
5604                         continue;
5605                 }
5606
5607                 factor = btrfs_bg_type_to_factor(block_group->flags);
5608                 free_bytes += (block_group->length -
5609                                block_group->used) * factor;
5610
5611                 spin_unlock(&block_group->lock);
5612         }
5613         spin_unlock(&sinfo->lock);
5614
5615         return free_bytes;
5616 }
5617
5618 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
5619                                    u64 start, u64 end)
5620 {
5621         return unpin_extent_range(fs_info, start, end, false);
5622 }
5623
5624 /*
5625  * It used to be that old block groups would be left around forever.
5626  * Iterating over them would be enough to trim unused space.  Since we
5627  * now automatically remove them, we also need to iterate over unallocated
5628  * space.
5629  *
5630  * We don't want a transaction for this since the discard may take a
5631  * substantial amount of time.  We don't require that a transaction be
5632  * running, but we do need to take a running transaction into account
5633  * to ensure that we're not discarding chunks that were released or
5634  * allocated in the current transaction.
5635  *
5636  * Holding the chunks lock will prevent other threads from allocating
5637  * or releasing chunks, but it won't prevent a running transaction
5638  * from committing and releasing the memory that the pending chunks
5639  * list head uses.  For that, we need to take a reference to the
5640  * transaction and hold the commit root sem.  We only need to hold
5641  * it while performing the free space search since we have already
5642  * held back allocations.
5643  */
5644 static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
5645 {
5646         u64 start = SZ_1M, len = 0, end = 0;
5647         int ret;
5648
5649         *trimmed = 0;
5650
5651         /* Discard not supported = nothing to do. */
5652         if (!blk_queue_discard(bdev_get_queue(device->bdev)))
5653                 return 0;
5654
5655         /* Not writable = nothing to do. */
5656         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
5657                 return 0;
5658
5659         /* No free space = nothing to do. */
5660         if (device->total_bytes <= device->bytes_used)
5661                 return 0;
5662
5663         ret = 0;
5664
5665         while (1) {
5666                 struct btrfs_fs_info *fs_info = device->fs_info;
5667                 u64 bytes;
5668
5669                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
5670                 if (ret)
5671                         break;
5672
5673                 find_first_clear_extent_bit(&device->alloc_state, start,
5674                                             &start, &end,
5675                                             CHUNK_TRIMMED | CHUNK_ALLOCATED);
5676
5677                 /* Check if there are any CHUNK_* bits left */
5678                 if (start > device->total_bytes) {
5679                         WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
5680                         btrfs_warn_in_rcu(fs_info,
5681 "ignoring attempt to trim beyond device size: offset %llu length %llu device %s device size %llu",
5682                                           start, end - start + 1,
5683                                           rcu_str_deref(device->name),
5684                                           device->total_bytes);
5685                         mutex_unlock(&fs_info->chunk_mutex);
5686                         ret = 0;
5687                         break;
5688                 }
5689
5690                 /* Ensure we skip the reserved area in the first 1M */
5691                 start = max_t(u64, start, SZ_1M);
5692
5693                 /*
5694                  * If find_first_clear_extent_bit find a range that spans the
5695                  * end of the device it will set end to -1, in this case it's up
5696                  * to the caller to trim the value to the size of the device.
5697                  */
5698                 end = min(end, device->total_bytes - 1);
5699
5700                 len = end - start + 1;
5701
5702                 /* We didn't find any extents */
5703                 if (!len) {
5704                         mutex_unlock(&fs_info->chunk_mutex);
5705                         ret = 0;
5706                         break;
5707                 }
5708
5709                 ret = btrfs_issue_discard(device->bdev, start, len,
5710                                           &bytes);
5711                 if (!ret)
5712                         set_extent_bits(&device->alloc_state, start,
5713                                         start + bytes - 1,
5714                                         CHUNK_TRIMMED);
5715                 mutex_unlock(&fs_info->chunk_mutex);
5716
5717                 if (ret)
5718                         break;
5719
5720                 start += len;
5721                 *trimmed += bytes;
5722
5723                 if (fatal_signal_pending(current)) {
5724                         ret = -ERESTARTSYS;
5725                         break;
5726                 }
5727
5728                 cond_resched();
5729         }
5730
5731         return ret;
5732 }
5733
5734 /*
5735  * Trim the whole filesystem by:
5736  * 1) trimming the free space in each block group
5737  * 2) trimming the unallocated space on each device
5738  *
5739  * This will also continue trimming even if a block group or device encounters
5740  * an error.  The return value will be the last error, or 0 if nothing bad
5741  * happens.
5742  */
5743 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
5744 {
5745         struct btrfs_block_group *cache = NULL;
5746         struct btrfs_device *device;
5747         struct list_head *devices;
5748         u64 group_trimmed;
5749         u64 range_end = U64_MAX;
5750         u64 start;
5751         u64 end;
5752         u64 trimmed = 0;
5753         u64 bg_failed = 0;
5754         u64 dev_failed = 0;
5755         int bg_ret = 0;
5756         int dev_ret = 0;
5757         int ret = 0;
5758
5759         /*
5760          * Check range overflow if range->len is set.
5761          * The default range->len is U64_MAX.
5762          */
5763         if (range->len != U64_MAX &&
5764             check_add_overflow(range->start, range->len, &range_end))
5765                 return -EINVAL;
5766
5767         cache = btrfs_lookup_first_block_group(fs_info, range->start);
5768         for (; cache; cache = btrfs_next_block_group(cache)) {
5769                 if (cache->start >= range_end) {
5770                         btrfs_put_block_group(cache);
5771                         break;
5772                 }
5773
5774                 start = max(range->start, cache->start);
5775                 end = min(range_end, cache->start + cache->length);
5776
5777                 if (end - start >= range->minlen) {
5778                         if (!btrfs_block_group_done(cache)) {
5779                                 ret = btrfs_cache_block_group(cache, 0);
5780                                 if (ret) {
5781                                         bg_failed++;
5782                                         bg_ret = ret;
5783                                         continue;
5784                                 }
5785                                 ret = btrfs_wait_block_group_cache_done(cache);
5786                                 if (ret) {
5787                                         bg_failed++;
5788                                         bg_ret = ret;
5789                                         continue;
5790                                 }
5791                         }
5792                         ret = btrfs_trim_block_group(cache,
5793                                                      &group_trimmed,
5794                                                      start,
5795                                                      end,
5796                                                      range->minlen);
5797
5798                         trimmed += group_trimmed;
5799                         if (ret) {
5800                                 bg_failed++;
5801                                 bg_ret = ret;
5802                                 continue;
5803                         }
5804                 }
5805         }
5806
5807         if (bg_failed)
5808                 btrfs_warn(fs_info,
5809                         "failed to trim %llu block group(s), last error %d",
5810                         bg_failed, bg_ret);
5811         mutex_lock(&fs_info->fs_devices->device_list_mutex);
5812         devices = &fs_info->fs_devices->devices;
5813         list_for_each_entry(device, devices, dev_list) {
5814                 ret = btrfs_trim_free_extents(device, &group_trimmed);
5815                 if (ret) {
5816                         dev_failed++;
5817                         dev_ret = ret;
5818                         break;
5819                 }
5820
5821                 trimmed += group_trimmed;
5822         }
5823         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
5824
5825         if (dev_failed)
5826                 btrfs_warn(fs_info,
5827                         "failed to trim %llu device(s), last error %d",
5828                         dev_failed, dev_ret);
5829         range->len = trimmed;
5830         if (bg_ret)
5831                 return bg_ret;
5832         return dev_ret;
5833 }