Date: Fri, 27 May 2011 16:27:47 -0400
From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <jaxboe@fusionio.com>
Cc: Namhyung Kim <namhyung@gmail.com>, Mike Snitzer <snitzer@redhat.com>,
        Christoph Hellwig <hch@infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH 1/2] blktrace: treat flush as barrier
Message-ID: <20110527202747.GA4803@infradead.org>
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On Fri, May 27, 2011 at 10:17:09PM +0200, Jens Axboe wrote:
> Agree on Christophs comments, we should not pretend they are the same
> (since they are not). Since flush is a request on its own, F works
> nicely. For FUA it's associated with a write, so F should work there too
> indicating Write Fua (and easily humanly parsed as that, or Write
> Flush). WU would look confusing.

REQ_FLUSH can also be set on a write bio, it only gets split at the
request level.  And even there we're at least pondering allowing it
to stay as part of the write for some paravirtualized storage protocols.

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