From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 1/3] xen/blk[front|back]: Use the full FLUSH | FUA
 instead of just FLUSH.
Date: Sat, 10 Sep 2011 14:08:49 -0400
Message-ID: <20110910180849.GA6621@infradead.org>
References: <1315593060-20031-1-git-send-email-konrad.wilk@oracle.com>
 <1315593060-20031-2-git-send-email-konrad.wilk@oracle.com>
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To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, JBeulich@novell.com, jeremy.fitzhardinge@citrix.com, axboe@kernel.dk
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On Fri, Sep 09, 2011 at 02:30:59PM -0400, Konrad Rzeszutek Wilk wrote:
> During a FLUSH we can pass sector number that we want to
> have flushed - which is what FUA requests are.

No, that is not the case.

REQ_FLUSH without data		-> pure flush
REQ_FLUSH with data		-> preflush plus write
REQ_FUA				-> write and ranged postflush