Re: [Qemu-devel] [RFC 00/13] aio: drop io_flush()

[Stefan Hajnoczi]

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.

Stefan