tree 9313d3b1f40869fbba03a443df788da4799a404f
parent 7f024fcd5c97dc70bb9121c80407cf3cf9be7159
author J. Bruce Fields <bfields@redhat.com> 1629493324 -0400
committer Chuck Lever <chuck.lever@oracle.com> 1630006330 -0400

nfs: don't atempt blocking locks on nfs reexports

NFS implements blocking locks by blocking inside its lock method.  In
the reexport case, this blocks the nfs server thread, which could lead
to deadlocks since an nfs server thread might be required to unlock the
conflicting lock.  It also causes a crash, since the nfs server thread
assumes it can free the lock when its lm_notify lock callback is called.

Ideal would be to make the nfs lock method return without blocking in
this case, but for now it works just not to attempt blocking locks.  The
difference is just that the original client will have to poll (as it
does in the v4.0 case) instead of getting a callback when the lock's
available.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>