From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [RFC][PATCH] libata: enable SATA disk fua detection on default
Date: Wed, 9 May 2012 09:23:17 -0400
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To: Christoph Hellwig <hch@infradead.org>, Robert Hancock <hancockrwd@gmail.com>, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, Jeff Garzik <jeff@garzik.org>, Zheng Liu <wenqing.lz@taobao.com>

On Wed, May 09, 2012 at 08:48:04PM +0800, Zheng Liu wrote:
> Thanks for your explanation.  It seems that there still has a problem.
> If I set the disk to write through mode, I need to modify my application
> to remove all of flush/sync operations.  It is unacceptable for us.

You don't have to - the kernel will not send a SYNCHRONIZE CACHE command
unless the disk advertises a write back cache.