From: Anthony Liguori <anthony@codemonkey.ws>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] fix bdrv_aio_read API breakage in qcow2
Date: Fri, 31 Oct 2008 12:32:05 -0500 [thread overview]
Message-ID: <490B4115.5040806@codemonkey.ws> (raw)
In-Reply-To: <20081022141459.GA26426@duo.random>
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
next prev parent reply other threads:[~2008-10-31 17:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-29 13:52 [Qemu-devel] [PATCH] ide_dma_cancel will result in partial DMA transfer Andrea Arcangeli
2008-09-01 10:43 ` [Qemu-devel] [PATCH 1/2] " Andrea Arcangeli
2008-09-01 10:53 ` [Qemu-devel] [PATCH 2/2] fix bdrv_aio_read API breakage in qcow2 Andrea Arcangeli
2008-10-22 14:14 ` [Qemu-devel] [PATCH] " Andrea Arcangeli
2008-10-27 13:49 ` Anthony Liguori
2008-10-31 17:32 ` Anthony Liguori [this message]
2009-01-14 18:06 ` [Qemu-devel] [PATCH] ide_dma_cancel will result in partial DMA transfer Andrea Arcangeli
2009-01-16 16:41 ` Ian Jackson
2009-01-22 19:02 ` Anthony Liguori
2009-02-26 16:43 ` Andrea Arcangeli
2008-09-01 11:21 ` Ian Jackson
2008-09-01 12:13 ` Andrea Arcangeli
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