From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:37689)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1TtaTi-0001VU-F4
	for qemu-devel@nongnu.org; Fri, 11 Jan 2013 04:00:44 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1TtaTb-0000bP-1I
	for qemu-devel@nongnu.org; Fri, 11 Jan 2013 04:00:42 -0500
Received: from mx3-phx2.redhat.com ([209.132.183.24]:53785)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <pbonzini@redhat.com>) id 1TtaTa-0000b8-Od
	for qemu-devel@nongnu.org; Fri, 11 Jan 2013 04:00:34 -0500
Date: Fri, 11 Jan 2013 04:00:09 -0500 (EST)
From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <871023743.4876151.1357894809949.JavaMail.root@redhat.com>
In-Reply-To: <50EFC855.8090206@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH] sheepdog: implement direct write semantics
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Liu Yuan <namei.unix@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Stefan Hajnoczi <stefanha@gmail.com>, qemu-devel@nongnu.org, MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>

> bdrv_enable_write_cache() is always
> true for now, I guess this need generic change block layer to get the
> writethrough/writeback hints.

That's not correct.  Try hdparm with an IDE disk, or sysfs with a SCSI
disk (recent kernels will also support sysfs with an IDE or virtio-blk
disk) and you'll see that it changes.

Paolo