[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [RFC 00/13] aio: drop io_flush()
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [RFC 00/13] aio: drop io_flush() |
Date: |
Fri, 12 Apr 2013 14:22:08 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 12.04.2013 um 14:06 hat Stefan Hajnoczi geschrieben:
> On Fri, Apr 12, 2013 at 12:27 PM, Paolo Bonzini <address@hidden> wrote:
> > Il 12/04/2013 12:04, Kevin Wolf ha scritto:
> >> Or actually, if you want to avoid .bdrv_drain for now, the patch that I
> >> started when I thought a bit about this, had a default .bdrv_drain
> >> implementation that just forwarded the request to bs->file if it wasn't
> >> implemented by a block driver. For the QED case, this would work.
> >
> > It's similar to bdrv_co_flush. Drain bs first, then bs->backing_hd
> > (this is not needed in bdrv_co_flush), then bs->file, then the driver
> > can do it on other files.
>
> Thanks for explaining Kevin. I didn't check whether bdrv_states
> included all BlockDriverStates.
>
> The simplest solution is to put all BlockDriverStates on a global list.
>
> A .bdrv_drain() interface is more flexible but I don't see a need for it yet.
We don't need the .bdrv_drain() callback yet, but please implement it
without a global list and with a function that forwards requests to
bs->file and bs->backing_hd like Paolo suggested. This will be the
obvious place to add the .bdrv_drain() callback later.
The reason why I prefer this approach is that it allows draining a
single BlockDriverState. After your patches we're really close to
enabling this and converting some bdrv_drain_all() to more specific
bdrv_drain(bs) calls.
Kevin
- [Qemu-devel] [RFC 13/13] aio: drop io_flush argument, (continued)
- [Qemu-devel] [RFC 13/13] aio: drop io_flush argument, Stefan Hajnoczi, 2013/04/11
- [Qemu-devel] [RFC 06/13] block/iscsi: drop iscsi_process_flush(), Stefan Hajnoczi, 2013/04/11
- [Qemu-devel] [RFC 04/13] block/curl: drop curl_aio_flush(), Stefan Hajnoczi, 2013/04/11
- [Qemu-devel] [RFC 08/13] block/nbd: drop nbd_have_request(), Stefan Hajnoczi, 2013/04/11
- [Qemu-devel] [RFC 02/13] dataplane/virtio-blk: check exit conditions before aio_poll(), Stefan Hajnoczi, 2013/04/11
- Re: [Qemu-devel] [RFC 00/13] aio: drop io_flush(), Kevin Wolf, 2013/04/12