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Date: Thu, 20 Sep 2001 10:38:05 -0400
From: Chris Mason <mason@suse.com>
To: Alexander Viro <viro@math.psu.edu>, Andrea Arcangeli <andrea@suse.de>
cc: Linus Torvalds <torvalds@transmeta.com>,
        Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Linux 2.4.10-pre11
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On Thursday, September 20, 2001 09:56:22 AM -0400 Alexander Viro <viro@math.psu.edu> wrote:

> Had you actually read the fsync_dev()?  Let me make it clear: you are
> flushing _buffer_ cache upon blkdev_put(bdev, BDEV_FILE).  It was
> the right thing when file access went through buffer cache.  It's
> blatantly wrong with page cache.

Well, fsync_dev will flush anything on the dirty list.  Since 
blkdev_commit_write puts things on the dirty list, andrea's current 
code will flush changes through the page cache.

The biggest exception is blkdev_writepage directly submits the io instead
of marking the buffers dirty.  This means the buffers won't be on
the locked/dirty list, and they won't get waited on.  Similar problem
for direct io.

The fix shouldn't be too bad, I'll code it up...

-chris