diff options
| -rw-r--r-- | fs/btrfs/extent-tree.c | 25 | ||||
| -rw-r--r-- | fs/btrfs/locking.h | 5 |
2 files changed, 30 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index b76df4d9d1ee..3dfe651aeaa9 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2425,6 +2425,31 @@ int btrfs_cross_ref_exist(struct btrfs_inode *inode, u64 offset, if (ret && ret != -ENOENT) goto out; + /* + * The path must have a locked leaf from the extent tree where + * the extent item for our extent is located, in case it exists, + * or where it should be located in case it doesn't exist yet + * because it's new and its delayed ref was not yet flushed. + * We need to lock the delayed ref head at check_delayed_ref(), + * if one exists, while holding the leaf locked in order to not + * race with delayed ref flushing, missing references and + * incorrectly reporting that the extent is not shared. + */ + if (IS_ENABLED(CONFIG_BTRFS_ASSERT)) { + struct extent_buffer *leaf = path->nodes[0]; + + ASSERT(leaf != NULL); + btrfs_assert_tree_read_locked(leaf); + + if (ret != -ENOENT) { + struct btrfs_key key; + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + ASSERT(key.objectid == bytenr); + ASSERT(key.type == BTRFS_EXTENT_ITEM_KEY); + } + } + ret = check_delayed_ref(inode, path, offset, bytenr); } while (ret == -EAGAIN && !path->nowait); diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h index 35036b151bf5..c69e57ff804b 100644 --- a/fs/btrfs/locking.h +++ b/fs/btrfs/locking.h @@ -199,8 +199,13 @@ static inline void btrfs_assert_tree_write_locked(struct extent_buffer *eb) { lockdep_assert_held_write(&eb->lock); } +static inline void btrfs_assert_tree_read_locked(struct extent_buffer *eb) +{ + lockdep_assert_held_read(&eb->lock); +} #else static inline void btrfs_assert_tree_write_locked(struct extent_buffer *eb) { } +static inline void btrfs_assert_tree_read_locked(struct extent_buffer *eb) { } #endif void btrfs_unlock_up_safe(struct btrfs_path *path, int level); |