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Date: Mon, 15 Dec 2014 13:30:03 +0100
From: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20141215123003.GG4411@noname.str.redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 11/16] block/parallels: add support for
	backing files
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To: "Denis V. Lunev" <den@openvz.org>
Cc: Jeff Cody <jcody@redhat.com>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>, Roman Kagan <rkagan@parallels.com>

Am 15.12.2014 um 09:27 hat Denis V. Lunev geschrieben:
> From: Roman Kagan <rkagan@parallels.com>
> 
> Add backing file support to Parallels format driver.
> 
> That said, I think backing file operations should end up in the generic
> block layer, but that's a longer story...
> 
> Signed-off-by: Roman Kagan <rkagan@parallels.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Jeff Cody <jcody@redhat.com>
> CC: Kevin Wolf <kwolf@redhat.com>
> CC: Stefan Hajnoczi <stefanha@redhat.com>

How are users supposed to make use of this? bs->backing_file isn't set
during parallels_open(), so you generally dont' get a backing file.

Users might manually add -drive backing=..., but is there really no
support for storing the backing file in the image format? If so, perhaps
it's better not to support backing files at all here.

Kevin