Disallowing unlock operations during the NFSv3 grace period

[Juan Gomez]

I was wondering if any of the developers can explain why we disallow unlock
operations during the grace period of a NFSv3 server?
(fs/lockd/*)

I think we should allow unlock operations during the grace period and only
filter lock operations. This becomes specially important in
clustered NAS heads where some of the nodes may enter the grace period
during cluster recovery in addition to node reboots.

The side effect of rejecting unlock during the grace period in clustered
NAS heads is that unlocks are unfairly delayed when they happen
to hit the NAS head cluster nodes when they are recovering from a node
failure.

Juan