diff options
| -rw-r--r-- | fs/btrfs/backref.c | 27 | ||||
| -rw-r--r-- | fs/btrfs/backref.h | 1 | ||||
| -rw-r--r-- | fs/btrfs/extent_io.c | 18 |
3 files changed, 38 insertions, 8 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index e0ff71159071..dce3a16996b9 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -1613,12 +1613,14 @@ static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache, /* * Check if a data extent is shared or not. * - * @root: root inode belongs to - * @inum: inode number of the inode whose extent we are checking - * @bytenr: logical bytenr of the extent we are checking - * @roots: list of roots this extent is shared among - * @tmp: temporary list used for iteration - * @cache: a backref lookup result cache + * @root: The root the inode belongs to. + * @inum: Number of the inode whose extent we are checking. + * @bytenr: Logical bytenr of the extent we are checking. + * @extent_gen: Generation of the extent (file extent item) or 0 if it is + * not known. + * @roots: List of roots this extent is shared among. + * @tmp: Temporary list used for iteration. + * @cache: A backref lookup result cache. * * btrfs_is_data_extent_shared uses the backref walking code but will short * circuit as soon as it finds a root or inode that doesn't match the @@ -1632,6 +1634,7 @@ static void store_backref_shared_cache(struct btrfs_backref_shared_cache *cache, * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error. */ int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr, + u64 extent_gen, struct ulist *roots, struct ulist *tmp, struct btrfs_backref_shared_cache *cache) { @@ -1683,6 +1686,18 @@ int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr, if (ret < 0 && ret != -ENOENT) break; ret = 0; + /* + * If our data extent is not shared through reflinks and it was + * created in a generation after the last one used to create a + * snapshot of the inode's root, then it can not be shared + * indirectly through subtrees, as that can only happen with + * snapshots. In this case bail out, no need to check for the + * sharedness of extent buffers. + */ + if (level == -1 && + extent_gen > btrfs_root_last_snapshot(&root->root_item)) + break; + if (level >= 0) store_backref_shared_cache(cache, root, bytenr, level, false); diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h index fec77b30a249..52ae6957b414 100644 --- a/fs/btrfs/backref.h +++ b/fs/btrfs/backref.h @@ -77,6 +77,7 @@ int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid, struct btrfs_inode_extref **ret_extref, u64 *found_off); int btrfs_is_data_extent_shared(struct btrfs_root *root, u64 inum, u64 bytenr, + u64 extent_gen, struct ulist *roots, struct ulist *tmp, struct btrfs_backref_shared_cache *cache); diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 618c6890699a..46f89cbe6193 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -5574,10 +5574,24 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo, flags |= (FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN); } else if (fieinfo->fi_extents_max) { + u64 extent_gen; u64 bytenr = em->block_start - (em->start - em->orig_start); /* + * If two extent maps are merged, then their generation + * is set to the maximum between their generations. + * Otherwise its generation matches the one we have in + * corresponding file extent item. If we have a merged + * extent map, don't use its generation to speedup the + * sharedness check below. + */ + if (test_bit(EXTENT_FLAG_MERGED, &em->flags)) + extent_gen = 0; + else + extent_gen = em->generation; + + /* * As btrfs supports shared space, this information * can be exported to userspace tools via * flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0 @@ -5585,8 +5599,8 @@ int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo, * lookup stuff. */ ret = btrfs_is_data_extent_shared(root, btrfs_ino(inode), - bytenr, roots, - tmp_ulist, + bytenr, extent_gen, + roots, tmp_ulist, backref_cache); if (ret < 0) goto out_free; |