diff options
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/extent-io-tree.c | 131 |
1 files changed, 89 insertions, 42 deletions
diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c index def9c6a602ee..46f15a7ae66b 100644 --- a/fs/btrfs/extent-io-tree.c +++ b/fs/btrfs/extent-io-tree.c @@ -327,6 +327,36 @@ static void extent_io_tree_panic(struct extent_io_tree *tree, int err) "locking error: extent tree was modified by another thread while locked"); } +static void merge_prev_state(struct extent_io_tree *tree, struct extent_state *state) +{ + struct extent_state *prev; + + prev = prev_state(state); + if (prev && prev->end == state->start - 1 && prev->state == state->state) { + if (tree->inode) + btrfs_merge_delalloc_extent(tree->inode, state, prev); + state->start = prev->start; + rb_erase(&prev->rb_node, &tree->state); + RB_CLEAR_NODE(&prev->rb_node); + free_extent_state(prev); + } +} + +static void merge_next_state(struct extent_io_tree *tree, struct extent_state *state) +{ + struct extent_state *next; + + next = next_state(state); + if (next && next->start == state->end + 1 && next->state == state->state) { + if (tree->inode) + btrfs_merge_delalloc_extent(tree->inode, state, next); + state->end = next->end; + rb_erase(&next->rb_node, &tree->state); + RB_CLEAR_NODE(&next->rb_node); + free_extent_state(next); + } +} + /* * Utility function to look for merge candidates inside a given range. Any * extents with matching state are merged together into a single extent in the @@ -338,31 +368,11 @@ static void extent_io_tree_panic(struct extent_io_tree *tree, int err) */ static void merge_state(struct extent_io_tree *tree, struct extent_state *state) { - struct extent_state *other; - if (state->state & (EXTENT_LOCKED | EXTENT_BOUNDARY)) return; - other = prev_state(state); - if (other && other->end == state->start - 1 && - other->state == state->state) { - if (tree->inode) - btrfs_merge_delalloc_extent(tree->inode, state, other); - state->start = other->start; - rb_erase(&other->rb_node, &tree->state); - RB_CLEAR_NODE(&other->rb_node); - free_extent_state(other); - } - other = next_state(state); - if (other && other->start == state->end + 1 && - other->state == state->state) { - if (tree->inode) - btrfs_merge_delalloc_extent(tree->inode, state, other); - state->end = other->end; - rb_erase(&other->rb_node, &tree->state); - RB_CLEAR_NODE(&other->rb_node); - free_extent_state(other); - } + merge_prev_state(tree, state); + merge_next_state(tree, state); } static void set_state_bits(struct extent_io_tree *tree, @@ -384,19 +394,27 @@ static void set_state_bits(struct extent_io_tree *tree, * Insert an extent_state struct into the tree. 'bits' are set on the * struct before it is inserted. * - * This may return -EEXIST if the extent is already there, in which case the - * state struct is freed. + * Returns a pointer to the struct extent_state record containing the range + * requested for insertion, which may be the same as the given struct or it + * may be an existing record in the tree that was expanded to accommodate the + * requested range. In case of an extent_state different from the one that was + * given, the later can be freed or reused by the caller. + * + * On error it returns an error pointer. * * The tree lock is not taken internally. This is a utility function and * probably isn't what you want to call (see set/clear_extent_bit). */ -static int insert_state(struct extent_io_tree *tree, - struct extent_state *state, - u32 bits, struct extent_changeset *changeset) +static struct extent_state *insert_state(struct extent_io_tree *tree, + struct extent_state *state, + u32 bits, + struct extent_changeset *changeset) { struct rb_node **node; struct rb_node *parent = NULL; - const u64 end = state->end; + const u64 start = state->start - 1; + const u64 end = state->end + 1; + const bool try_merge = !(bits & (EXTENT_LOCKED | EXTENT_BOUNDARY)); set_state_bits(tree, state, bits, changeset); @@ -407,23 +425,42 @@ static int insert_state(struct extent_io_tree *tree, parent = *node; entry = rb_entry(parent, struct extent_state, rb_node); - if (end < entry->start) { + if (state->end < entry->start) { + if (try_merge && end == entry->start && + state->state == entry->state) { + if (tree->inode) + btrfs_merge_delalloc_extent(tree->inode, + state, entry); + entry->start = state->start; + merge_prev_state(tree, entry); + state->state = 0; + return entry; + } node = &(*node)->rb_left; - } else if (end > entry->end) { + } else if (state->end > entry->end) { + if (try_merge && entry->end == start && + state->state == entry->state) { + if (tree->inode) + btrfs_merge_delalloc_extent(tree->inode, + state, entry); + entry->end = state->end; + merge_next_state(tree, entry); + state->state = 0; + return entry; + } node = &(*node)->rb_right; } else { btrfs_err(tree->fs_info, "found node %llu %llu on insert of %llu %llu", - entry->start, entry->end, state->start, end); - return -EEXIST; + entry->start, entry->end, state->start, state->end); + return ERR_PTR(-EEXIST); } } rb_link_node(&state->rb_node, parent, node); rb_insert_color(&state->rb_node, &tree->state); - merge_state(tree, state); - return 0; + return state; } /* @@ -1133,6 +1170,8 @@ hit_next: */ if (state->start > start) { u64 this_end; + struct extent_state *inserted_state; + if (end < last_start) this_end = end; else @@ -1148,12 +1187,15 @@ hit_next: */ prealloc->start = start; prealloc->end = this_end; - err = insert_state(tree, prealloc, bits, changeset); - if (err) + inserted_state = insert_state(tree, prealloc, bits, changeset); + if (IS_ERR(inserted_state)) { + err = PTR_ERR(inserted_state); extent_io_tree_panic(tree, err); + } - cache_state(prealloc, cached_state); - prealloc = NULL; + cache_state(inserted_state, cached_state); + if (inserted_state == prealloc) + prealloc = NULL; start = this_end + 1; goto search_again; } @@ -1356,6 +1398,8 @@ hit_next: */ if (state->start > start) { u64 this_end; + struct extent_state *inserted_state; + if (end < last_start) this_end = end; else @@ -1373,11 +1417,14 @@ hit_next: */ prealloc->start = start; prealloc->end = this_end; - err = insert_state(tree, prealloc, bits, NULL); - if (err) + inserted_state = insert_state(tree, prealloc, bits, NULL); + if (IS_ERR(inserted_state)) { + err = PTR_ERR(inserted_state); extent_io_tree_panic(tree, err); - cache_state(prealloc, cached_state); - prealloc = NULL; + } + cache_state(inserted_state, cached_state); + if (inserted_state == prealloc) + prealloc = NULL; start = this_end + 1; goto search_again; } |