Branch: b_new_cmd

[fs/lustre-release.git] / lustre / ldlm / l_lock.c

diff --git a/lustre/ldlm/l_lock.c b/lustre/ldlm/l_lock.c
index 746b485..b652097 100644 (file)
--- a/lustre/ldlm/l_lock.c
+++ b/lustre/ldlm/l_lock.c
@@ -48,3 +48,39 @@
 #include <linux/lustre_dlm.h>
 #include <linux/lustre_lib.h>
 
+/*
+ * ldlm locking uses resource to serialize access to locks
+ * but there is a case when we change resource of lock upon
+ * enqueue reply. we rely on that lock->l_resource = new_res
+ * is atomic
+ */
+struct ldlm_resource * lock_res_and_lock(struct ldlm_lock *lock)
+{
+        struct ldlm_resource *res = lock->l_resource;
+
+        if (!res->lr_namespace->ns_client) {
+                /* on server-side resource of lock doesn't change */
+                lock_res(res);
+                return res;
+        } 
+
+        lock_bitlock(lock);
+        res = lock->l_resource;
+        lock_res(res);
+        return res;
+}
+
+void unlock_res_and_lock(struct ldlm_lock *lock)
+{
+        struct ldlm_resource *res = lock->l_resource;
+
+        if (!res->lr_namespace->ns_client) {
+                /* on server-side resource of lock doesn't change */
+                unlock_res(res);
+                return;
+        }
+
+        unlock_res(res);
+        unlock_bitlock(lock);
+}
+