This bug was fixed in the package btrfs-tools - 3.12-1ubuntu0.2
--------------- btrfs-tools (3.12-1ubuntu0.2) trusty; urgency=medium
* Cherry-pick upstream fix loop device mount checks (LP: #1735046)
-- Ryan Harper <email address hidden> Wed, 29 Nov 2017 13:44:30 -0600
This bug was fixed in the package btrfs-tools - 3.12-1ubuntu0.2
---------------
btrfs-tools (3.12-1ubuntu0.2) trusty; urgency=medium
* Cherry-pick upstream fix loop device mount checks
(LP: #1735046)
-- Ryan Harper <email address hidden> Wed, 29 Nov 2017 13:44:30 -0600