[PATCH 5/6] writeback: fix queue_io() ordering

[Wu Fengguang <fengguang.wu@intel.com>]

[-- Attachment #1: queue_io-fix.patch --]
[-- Type: text/plain, Size: 1227 bytes --]

This was not a bug, since b_io is empty for kupdate writeback.
The next patch will do requeue_io() for non-kupdate writeback,
so let's fix it.

CC: Dave Chinner <david@fromorbit.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 fs/fs-writeback.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- linux-next.orig/fs/fs-writeback.c	2010-07-11 09:13:31.000000000 +0800
+++ linux-next/fs/fs-writeback.c	2010-07-11 09:13:32.000000000 +0800
@@ -252,11 +252,14 @@ static void move_expired_inodes(struct l
 }
 
 /*
- * Queue all expired dirty inodes for io, eldest first.
+ * Queue all expired dirty inodes for io, eldest first:
+ * (newly dirtied) => b_dirty inodes
+ *                 => b_more_io inodes
+ *                 => remaining inodes in b_io => (dequeue for sync)
  */
 static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
 {
-	list_splice_init(&wb->b_more_io, wb->b_io.prev);
+	list_splice_init(&wb->b_more_io, &wb->b_io);
 	move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
 }