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Date: Thu, 5 Aug 2010 16:39:28 -0400
From: "Ted Ts'o" <tytso@mit.edu>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: Avi Kivity <avi@redhat.com>, Christoph Hellwig <hch@infradead.org>,
        Ric Wheeler <rwheeler@redhat.com>, Mingming Cao <cmm@us.ibm.com>,
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        linux-kernel <linux-kernel@vger.kernel.org>,
        Keith Mannthey <kmannth@us.ibm.com>, Mingming Cao <mcao@us.ibm.com>
Subject: Re: [RFC] ext4: Don't send extra barrier during fsync if there are
 no dirty pages.
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On Thu, Aug 05, 2010 at 03:13:44PM -0400, Jeff Moyer wrote:
> > IO_CMD_FSYNC doesn't exist right now, but sure, it means we don't have
> 
> Well, there's IOCB_CMD_FSYNC.  But still, this isn't the same thing as
> what's requested.  If I understand correctly, what is requested is a
> mechanism to flush out all data for multiple file descriptors and follow
> that with a single barrier/flush (and yes, Ted did give a summary of the
> commands that would be required to accomplish that).
> 
> There still remains the question of why this should be tied to the AIO
> submission interface.

I don't think it should, personally.  The only excuse might be if
someone wanted to do an asynchronous fsync(), but I don't think that
makes sense in most cases.

					- Ted
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