[PATCH] ocfs2/dlm: Fixes oops in dlm_new_lockres()

Patch fixes a race that can result in an oops while adding a
lockres to the dlm lockres tracking list.

Bug introduced by mainline commit 29576f8bb54045be944ba809d4fca1ad77c94165.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

fs/ocfs2/dlm/dlmmaster.c

@@ -606,7 +606,9 @@ static void dlm_init_lockres(struct dlm_ctxt *dlm,
 
 	res->last_used = 0;
 
+	spin_lock(&dlm->spinlock);
 	list_add_tail(&res->tracking, &dlm->tracking_list);
+	spin_unlock(&dlm->spinlock);
 
 	memset(res->lvb, 0, DLM_LVB_LEN);
 	memset(res->refmap, 0, sizeof(res->refmap));