LU-2332 osc: solve a race in client obd list lock

[fs/lustre-release.git] / lustre / include / linux / obd.h

diff --git a/lustre/include/linux/obd.h b/lustre/include/linux/obd.h
index 780c2b8..0be9fa1 100644 (file)
--- a/lustre/include/linux/obd.h
+++ b/lustre/include/linux/obd.h
@@ -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.
@@ -26,8 +24,10 @@
  * GPL HEADER END
  */
 /*
- * Copyright  2008 Sun Microsystems, Inc. All rights reserved
+ * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, 2012, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -41,39 +41,109 @@
 #error Do not #include this file directly. #include <obd.h> instead
 #endif
 
+#include <obd_support.h>
+
 #ifdef __KERNEL__
 # include <linux/fs.h>
 # include <linux/list.h>
 # include <linux/sched.h>  /* for struct task_struct, for current.h */
-# include <asm/current.h>  /* for smp_lock.h */
-# include <linux/smp_lock.h>
 # include <linux/proc_fs.h>
 # include <linux/mount.h>
-# ifndef HAVE_VFS_INTENT_PATCHES
-#  include <linux/lustre_intent.h>
-# endif
+# include <linux/lustre_intent.h>
 #endif
 
-typedef spinlock_t client_obd_lock_t;
+struct ll_iattr {
+       struct iattr    iattr;
+       unsigned int    ia_attr_flags;
+};
 
-static inline void client_obd_list_lock_init(client_obd_lock_t *lock)
+#ifdef __KERNEL__
+#define CLIENT_OBD_LIST_LOCK_DEBUG 1
+#endif
+
+typedef struct {
+       spinlock_t              lock;
+
+#ifdef CLIENT_OBD_LIST_LOCK_DEBUG
+       unsigned long       time;
+       struct task_struct *task;
+       const char         *func;
+       int                 line;
+#endif
+} client_obd_lock_t;
+
+#ifdef CLIENT_OBD_LIST_LOCK_DEBUG
+static inline void __client_obd_list_lock(client_obd_lock_t *lock,
+                                          const char *func, int line)
 {
-        spin_lock_init(lock);
+       unsigned long cur = jiffies;
+       while (1) {
+               if (spin_trylock(&lock->lock)) {
+                        LASSERT(lock->task == NULL);
+                        lock->task = current;
+                        lock->func = func;
+                        lock->line = line;
+                        lock->time = jiffies;
+                        break;
+                }
+
+                if ((jiffies - cur > 5 * CFS_HZ) &&
+                    (jiffies - lock->time > 5 * CFS_HZ)) {
+                       struct task_struct *task = lock->task;
+
+                       if (task == NULL)
+                               continue;
+
+                        LCONSOLE_WARN("%s:%d: lock %p was acquired"
+                                      " by <%s:%d:%s:%d> for %lu seconds.\n",
+                                     current->comm, current->pid,
+                                      lock, task->comm, task->pid,
+                                      lock->func, lock->line,
+                                      (jiffies - lock->time) / CFS_HZ);
+                        LCONSOLE_WARN("====== for process holding the "
+                                      "lock =====\n");
+                        libcfs_debug_dumpstack(task);
+                        LCONSOLE_WARN("====== for current process =====\n");
+                        libcfs_debug_dumpstack(NULL);
+                        LCONSOLE_WARN("====== end =======\n");
+                        cfs_pause(1000 * CFS_HZ);
+                }
+               cpu_relax();
+        }
 }
 
-static inline void client_obd_list_lock_done(client_obd_lock_t *lock)
-{}
+#define client_obd_list_lock(lock) \
+        __client_obd_list_lock(lock, __FUNCTION__, __LINE__)
 
+static inline void client_obd_list_unlock(client_obd_lock_t *lock)
+{
+       LASSERT(lock->task != NULL);
+       lock->task = NULL;
+       lock->time = jiffies;
+       spin_unlock(&lock->lock);
+}
+
+#else /* ifdef CLIENT_OBD_LIST_LOCK_DEBUG */
 static inline void client_obd_list_lock(client_obd_lock_t *lock)
 {
-        spin_lock(lock);
+       spin_lock(&lock->lock);
 }
 
 static inline void client_obd_list_unlock(client_obd_lock_t *lock)
 {
-        spin_unlock(lock);
+       spin_unlock(&lock->lock);
+}
+
+#endif /* ifdef CLIENT_OBD_LIST_LOCK_DEBUG */
+
+static inline void client_obd_list_lock_init(client_obd_lock_t *lock)
+{
+       spin_lock_init(&lock->lock);
 }
 
+static inline void client_obd_list_lock_done(client_obd_lock_t *lock)
+{}
+
 #if defined(__KERNEL__) && !defined(HAVE_ADLER)
 /* zlib_adler() is an inline function defined in zutil.h */
 #define HAVE_ADLER