On Tue, Feb 23, 2021 at 03:20:42PM +0200, Nikolay Borisov wrote:

If btrfs_qgroup_reserve_data returns an error (i.e quota limit reached)
the handling logic directly goes to the 'out' label without first
unlocking the extent range between lockstart, lockend. This results in
deadlocks as processes try to lock the same extent.

Fixes: a7f8b1c2ac21 ("btrfs: file: reserve qgroup space after the hole punch range is locked")
Signed-off-by: Nikolay Borisov <redacted>

Added to misc-next, thanks.