Commit 327b1cf8 authored by Liu Bo's avatar Liu Bo Committed by Greg Kroah-Hartman

Btrfs: fix unexpected return value of fiemap

commit 2d324f59 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: default avatarLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ac5414fc
......@@ -4385,8 +4385,12 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
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;
......
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