LU-15167 quota: fallocate send UID/GID for quota

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

diff --git a/lustre/ldlm/l_lock.c b/lustre/ldlm/l_lock.c
index ce2bdad..0c10b30 100644 (file)
--- a/lustre/ldlm/l_lock.c
+++ b/lustre/ldlm/l_lock.c
@@ -1,6 +1,4 @@
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
+/*
  * GPL HEADER START
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
@@ -17,64 +15,59 @@
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
 /*
  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
+ *
+ * Copyright (c) 2012, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
- * Lustre is a trademark of Sun Microsystems, Inc.
  */
 
 #define DEBUG_SUBSYSTEM S_LDLM
-#ifdef __KERNEL__
 #include <libcfs/libcfs.h>
-#else 
-#include <liblustre.h>
-#endif
 
 #include <lustre_dlm.h>
 #include <lustre_lib.h>
 
-/*
- * ldlm locking uses resource to serialize access to locks
+/**
+ * Lock a lock and its resource.
+ *
+ * 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
+ * enqueue reply. We rely on rcu_assign_pointer(lock->l_resource, new_res)
+ * being an atomic operation.
  */
-struct ldlm_resource * lock_res_and_lock(struct ldlm_lock *lock)
+struct ldlm_resource *lock_res_and_lock(struct ldlm_lock *lock)
 {
-        struct ldlm_resource *res = NULL;
-
-        cfs_spin_lock(&lock->l_lock);
-        res = lock->l_resource;
-
-        if (ns_is_server(res->lr_namespace))
-                /* on server-side resource of lock doesn't change */
-                cfs_spin_unlock(&lock->l_lock);
+       struct ldlm_resource *res;
 
-        lock_res(res);
-        return res;
+       rcu_read_lock();
+       while (1) {
+               res = rcu_dereference(lock->l_resource);
+               lock_res(res);
+               if (res == lock->l_resource) {
+                       ldlm_set_res_locked(lock);
+                       rcu_read_unlock();
+                       return res;
+               }
+               unlock_res(res);
+       }
 }
+EXPORT_SYMBOL(lock_res_and_lock);
 
+/**
+ * Unlock a lock and its resource previously locked with lock_res_and_lock
+ */
 void unlock_res_and_lock(struct ldlm_lock *lock)
 {
-        struct ldlm_resource *res = lock->l_resource;
-
-        if (ns_is_server(res->lr_namespace)) {
-                /* on server-side resource of lock doesn't change */
-                unlock_res(res);
-                return;
-        }
+       ldlm_clear_res_locked(lock);
 
-        unlock_res(res);
-        cfs_spin_unlock(&lock->l_lock);
+       unlock_res(lock->l_resource);
 }
+EXPORT_SYMBOL(unlock_res_and_lock);