jbd2: add lockdep support

Ported from similar patch for the jbd layer.
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/jbd2/transaction.c

@@ -241,6 +241,8 @@ out:
 	return ret;
 }
 
+static struct lock_class_key jbd2_handle_key;
+
 /* Allocate a new handle.  This should probably be in a slab... */
 static handle_t *new_handle(int nblocks)
 {
@@ -251,6 +253,9 @@ static handle_t *new_handle(int nblocks)
 	handle->h_buffer_credits = nblocks;
 	handle->h_ref = 1;
 
+	lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle",
+						&jbd2_handle_key, 0);
+
 	return handle;
 }
 
@@ -293,7 +298,11 @@ handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
 		jbd2_free_handle(handle);
 		current->journal_info = NULL;
 		handle = ERR_PTR(err);
+		goto out;
 	}
+
+	lock_acquire(&handle->h_lockdep_map, 0, 0, 0, 2, _THIS_IP_);
+out:
 	return handle;
 }
 
@@ -1419,6 +1428,8 @@ int jbd2_journal_stop(handle_t *handle)
 		spin_unlock(&journal->j_state_lock);
 	}
 
+	lock_release(&handle->h_lockdep_map, 1, _THIS_IP_);
+
 	jbd2_free_handle(handle);
 	return err;
 }

include/linux/jbd2.h

@@ -418,6 +418,10 @@ struct handle_s
 	unsigned int	h_sync:		1;	/* sync-on-close */
 	unsigned int	h_jdata:	1;	/* force data journaling */
 	unsigned int	h_aborted:	1;	/* fatal error on handle */
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	h_lockdep_map;
+#endif
 };