[PATCH] lockdep: annotate i_mutex

Teach special (recursive) locking code to the lock validator.  Has no effect
on non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/fs.h

@@ -542,6 +542,25 @@ struct inode {
 #endif
 };
 
+/*
+ * inode->i_mutex nesting subclasses for the lock validator:
+ *
+ * 0: the object of the current VFS operation
+ * 1: parent
+ * 2: child/target
+ * 3: quota file
+ *
+ * The locking order between these classes is
+ * parent -> child -> normal -> quota
+ */
+enum inode_i_mutex_lock_class
+{
+	I_MUTEX_NORMAL,
+	I_MUTEX_PARENT,
+	I_MUTEX_CHILD,
+	I_MUTEX_QUOTA
+};
+
 /*
  * NOTE: in a 32bit arch with a preemptable kernel and
  * an UP compile the i_size_read/write must be atomic