Re: [PATCH 2/5] virtio_blk: implement REQ_FLUSH/FUA support

From: Christoph Hellwig
Date: Mon Aug 16 2010 - 14:34:01 EST


On Mon, Aug 16, 2010 at 06:52:00PM +0200, Tejun Heo wrote:
> From: Tejun Heo <tj@xxxxxxxxxx>
>
> 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.

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