From: Filipe Manana fdmanana@suse.com
commit adbd914dcde0b03bfc08ffe40b81f31b0457833f upstream.
On a zoned filesystem, sometimes we need to split an ordered extent into 3 different ordered extents. The original ordered extent is shortened, at the front and at the rear, and we create two other new ordered extents to represent the trimmed parts of the original ordered extent.
After adjusting the original ordered extent, we create an ordered extent to represent the pre-range, and that may fail with ENOMEM for example. After that we always try to create the ordered extent for the post-range, and if that happens to succeed we end up returning success to the caller as we overwrite the 'ret' variable which contained the previous error.
This means we end up with a file range for which there is no ordered extent, which results in the range never getting a new file extent item pointing to the new data location. And since the split operation did not return an error, writeback does not fail and the inode's mapping is not flagged with an error, resulting in a subsequent fsync not reporting an error either.
It's possibly very unlikely to have the creation of the post-range ordered extent succeed after the creation of the pre-range ordered extent failed, but it's not impossible.
So fix this by making sure we only create the post-range ordered extent if there was no error creating the ordered extent for the pre-range.
Fixes: d22002fd37bd97 ("btrfs: zoned: split ordered extent when bio is sent") CC: stable@vger.kernel.org # 5.12+ Signed-off-by: Filipe Manana fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/ordered-data.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -995,7 +995,7 @@ int btrfs_split_ordered_extent(struct bt
if (pre) ret = clone_ordered_extent(ordered, 0, pre); - if (post) + if (ret == 0 && post) ret = clone_ordered_extent(ordered, pre + ordered->disk_num_bytes, post);