[PATCH 05/13] writeback: fix queue_io() ordering

Wu Fengguang
2010-08-05T16:10:56Z

[-- Attachment #1: queue_io-fix.patch --]
[-- Type: text/plain, Size: 1548 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: Wu Fengguang <fengguang.wu@intel.com>
---
fs/fs-writeback.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

--- linux-next.orig/fs/fs-writeback.c 2010-08-05 23:03:37.000000000 +0800
+++ linux-next/fs/fs-writeback.c 2010-08-05 23:21:43.000000000 +0800
@@ -253,10 +253,18 @@ static void move_expired_inodes(struct l

/*
* Queue all expired dirty inodes for io, eldest first.
+ * Before
+ * newly dirtied b_dirty b_io b_more_io
+ * =============> gf edc BA
+ * After
+ * newly dirtied b_dirty b_io b_more_io
+ * =============> g fBAedc
+ * |
+ * +--> dequeue for IO
*/
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);
}