From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 2/5] virtio_blk: implement REQ_FLUSH/FUA support Date: Mon, 16 Aug 2010 20:33:17 +0200 Message-ID: <20100816183317.GA28171@lst.de> References: <1281977523-19335-1-git-send-email-tj@kernel.org> <1281977523-19335-3-git-send-email-tj@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1281977523-19335-3-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Tejun Heo Cc: jaxboe@fusionio.com, linux-fsdevel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, hch@lst.de, James.Bottomley@suse.de, tytso@mit.edu, chris.mason@oracle.com, swhiteho@redhat.com, konishi.ryusuke@lab.ntt.co.jp, dm-devel@redhat.com, vst@vlnb.net, jack@suse.cz, rwheeler@redhat.com, hare@suse.de, neilb@suse.de, rusty@rustcorp.com.au, mst@redhat.com, Tejun Heo List-Id: linux-raid.ids On Mon, Aug 16, 2010 at 06:52:00PM +0200, Tejun Heo wrote: > From: Tejun Heo > > Remove now unused REQ_HARDBARRIER support and implement REQ_FLUSH/FUA > support instead. A new feature flag VIRTIO_BLK_F_FUA is added to > indicate the support for FUA. I'm not sure it's worth it. The pure REQ_FLUSH path works not and is well tested with kvm/qemu. We can still easily add a FUA bit, and even a pre-flush bit if the protocol roundtrips matter in real life benchmarking.