fs: dlm: avoid comms shutdown delay in release_lockspace

When dlm_release_lockspace does active shutdown on connections to
other nodes, the active shutdown will wait for any exisitng passive
shutdowns to be resolved.  But, the sequence of operations during
dlm_release_lockspace can prevent the normal resolution of passive
shutdowns (processed normally by way of lockspace recovery.)
This disruption of passive shutdown handling can cause the active
shutdown to wait for a full timeout period, delaying the completion
of dlm_release_lockspace.

To fix this, make dlm_release_lockspace resolve existing passive
shutdowns (by calling dlm_clear_members earlier), before it does
active shutdowns.  The active shutdowns will not find any passive
shutdowns to wait for, and will not be delayed.

Reported-by: Chris Mackowski <cmackows@redhat.com>
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

Author: Alexander Aring

fs/dlm/lockspace.c

@@ -793,6 +793,7 @@ static int release_lockspace(struct dlm_ls *ls, int force)
 
 	if (ls_count == 1) {
 		dlm_scand_stop();
+		dlm_clear_members(ls);
 		dlm_midcomms_shutdown();
 	}