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Date: Fri, 31 Oct 2008 12:32:05 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH] fix bdrv_aio_read API breakage in qcow2
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To: qemu-devel@nongnu.org

Andrea Arcangeli wrote:
> From: Andrea Arcangeli <aarcange@redhat.com>
>
> I noticed the qemu_aio_flush was doing nothing at all. And a flood of
> cmd_writeb commands leading to a noop-invocation of qemu_aio_flush
> were executed.
>
> In short all 'memset;goto redo' places must be fixed to use the bh and
> not to call the callback in the context of bdrv_aio_read or the
> bdrv_aio_read model falls apart. Reading from qcow2 holes is possible
> with phyisical readahead (kind of breada in linux buffer cache).
>
> This is needed at least for scsi, ide is lucky (or it has been
> band-aided against this API breakage by fixing the symptom and not the
> real bug).
>
> Same bug exists in qcow of course, can be fixed later as it's less
> urgent.
>
> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
> --
>   
Applied.  Thanks.

Regards,

Anthony Liguori