dlm: improve how bast mode handling

The lkb bastmode value is set in the context of processing the
lock, and read by the dlm_astd thread.  Because it's accessed
in these two separate contexts, the writing/reading ought to
be done under a lock.  This is simple to do by setting it and
reading it when the lkb is added to and removed from dlm_astd's
callback list which is properly locked.

Signed-off-by: David Teigland <teigland@redhat.com>
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index b3832c6..065149e 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -175,7 +175,7 @@
 /* we could possibly check if the cancel of an orphan has resulted in the lkb
    being removed and then remove that lkb from the orphans list and free it */
 
-void dlm_user_add_ast(struct dlm_lkb *lkb, int type)
+void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int bastmode)
 {
 	struct dlm_ls *ls;
 	struct dlm_user_args *ua;
@@ -208,6 +208,8 @@
 
 	ast_type = lkb->lkb_ast_type;
 	lkb->lkb_ast_type |= type;
+	if (bastmode)
+		lkb->lkb_bastmode = bastmode;
 
 	if (!ast_type) {
 		kref_get(&lkb->lkb_ref);