tree 99b8b64ea08d4990373d09e01b7bac2566ad3879
parent 0f8e0d9a317406612700426fad3efab0b7bbc467
author David Teigland <teigland@redhat.com> 1219077810 -0500
committer David Teigland <teigland@redhat.com> 1219942183 -0500

dlm: detect available userspace daemon

If dlm_controld (the userspace daemon that controls the setup and
recovery of the dlm) fails, the kernel should shut down the lockspaces
in the kernel rather than leaving them running.  This is detected by
having dlm_controld hold a misc device open while running, and if
the kernel detects a close while the daemon is still needed, it stops
the lockspaces in the kernel.

Knowing that the userspace daemon isn't running also allows the
lockspace create/remove routines to avoid waiting on the daemon
for join/leave operations.

Signed-off-by: David Teigland <teigland@redhat.com>