BugLink: https://bugs.launchpad.net/bugs/1811647

commit 23851e97 upstream.

Fixes 3d6aa675 ("dlm: keep lkbs in idr")
Cc: stable@kernel.org # 3.1
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>