Fix 100% CPU usage when CMAP connection is lost

[susnux]

When CMAP disconnects sbd results in 100% CPU usage.

This patch is currently used on SUSE, so upstreaming seem reasonable.

[knet-ci-bot]

Can one of the admins verify this patch?

[wenningerk]

test this please

[gao-yan]

I think this has been tracked with https://github.com/ClusterLabs/sbd/pull/80 . Of course it probably needs to be revisited when we get a chance ...

[wenningerk]

Yep it is tracked there and was supposed to be solved together with corosync-graceful-shutdown detection/handling. At that time this wasn't easily possible but meanwhile corosync has added back an api that should allow easy detection of a graceful corosync shutdown. So this should be revisited asap. I'll take it on my list of urgent stuff ;-)

[wenningerk]

But let me keep this open for now as the patch here is a bit more elaborate and takes care of how inquisitor should react. But as said without graceful-corosync-shutdown detection this is of limited use anyway.