[DLM] fix user unlocking

When a user process exits, we clear all the locks it holds.  There is a
problem, though, with locks that the process had begun unlocking before it
exited.  We couldn't find the lkb's that were in the process of being
unlocked remotely, to flag that they are DEAD.  To solve this, we move
lkb's being unlocked onto a new list in the per-process structure that
tracks what locks the process is holding.  We can then go through this
list to flag the necessary lkb's when clearing locks for a process when it
exits.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index ee993c5c..61d9320 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -526,6 +526,7 @@
 	spinlock_t		asts_spin;
 	struct list_head	locks;
 	spinlock_t		locks_spin;
+	struct list_head	unlocking;
 	wait_queue_head_t	wait;
 };