4.5-stable review patch. If anyone has any objections, please let me know.
------------------ From: Liu Bo <[email protected]> commit 2d324f59f343967a03eeb2690f0ff178304d0687 upstream. btrfs's fiemap is supposed to return 0 on success and return < 0 on error. however, ret becomes 1 after looking up the last file extent: btrfs_lookup_file_extent -> btrfs_search_slot(..., ins_len=0, cow=0) and if the offset is beyond EOF, we'll get 'path' pointed to the place of potentail insertion, and ret == 1. This may confuse applications using ioctl(FIEL_IOC_FIEMAP). Signed-off-by: Liu Bo <[email protected]> Signed-off-by: David Sterba <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/btrfs/extent_io.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -4385,8 +4385,12 @@ int extent_fiemap(struct inode *inode, s if (ret < 0) { btrfs_free_path(path); return ret; + } else { + WARN_ON(!ret); + if (ret == 1) + ret = 0; } - WARN_ON(!ret); + path->slots[0]--; btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]); found_type = found_key.type;
