From: David Sterba dsterba@suse.com
[ Upstream commit 26b66d1d366a375745755ca7365f67110bbf6bd5 ]
The get_parent handler looks up a parent of a given dentry, this can be either a subvolume or a directory. The search is set up with offset -1 but it's never expected to find such item, as it would break allowed range of inode number or a root id. This means it's a corruption (ext4 also returns this error code).
Reviewed-by: Josef Bacik josef@toxicpanda.com Reviewed-by: Anand Jain anand.jain@oracle.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/export.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c index bfa2bf44529c2..d908afa1f313c 100644 --- a/fs/btrfs/export.c +++ b/fs/btrfs/export.c @@ -161,8 +161,15 @@ struct dentry *btrfs_get_parent(struct dentry *child) ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto fail; + if (ret == 0) { + /* + * Key with offset of -1 found, there would have to exist an + * inode with such number or a root with such id. + */ + ret = -EUCLEAN; + goto fail; + }
- BUG_ON(ret == 0); /* Key with offset of -1 found */ if (path->slots[0] == 0) { ret = -ENOENT; goto fail;