[Linux-cluster] Deadlock when using clvmd + OpenAIS + Corosync

[Evan Broder]

[please preserve the CC when replying, thanks]

Hi -
   We're attempting to setup a clvm (2.02.56) cluster using OpenAIS
(1.1.1) and Corosync (1.1.2). We've gotten bitten hard in the past by
crashes leaving DLM state around and forcing us to reboot our nodes,
so we're specifically looking for a solution that doesn't involve
in-kernel locking.

We're also running the Pacemaker OpenAIS service, as we're hoping to
use it for management of some other resources going forward.

We've managed to form the OpenAIS cluster, and get clvmd running on
both of our nodes. Operations using LVM succeed, so long as only one
operation runs at a time. However, if we attempt to run two operations
(say, one lvcreate on each host) at a time, they both hang, and both
clvmd processes appear to deadlock.

When they deadlock, it doesn't appear to affect the other clustering
processes - both corosync and pacemaker still report a fully formed
cluster, so it seems the issue is localized to clvmd.

I've looked at logs from corosync and pacemaker, and I've straced
various processes, but I don't want to blast a bunch of useless
information at the list. What information can I provide to make it
easier to debug and fix this deadlock?

Thanks,
 - Evan