[RFC][PATCH 2/7] writeback: fix queue_io() ordering

Wu Fengguang
2009-09-09T15:08:31Z

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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>
---
fs/fs-writeback.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- linux.orig/fs/fs-writeback.c 2009-09-09 21:41:14.000000000 +0800
+++ linux/fs/fs-writeback.c 2009-09-09 21:45:15.000000000 +0800
@@ -313,11 +313,14 @@ 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);
}

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