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Date: Sat, 08 Jun 2013 01:23:02 +0800
From: Liu Yuan <namei.unix@gmail.com>
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Subject: Re: [Qemu-devel] [PATCH 2/2] sheepdog: support 'qemu-img snapshot
	-a'
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To: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>, sheepdog@lists.wpkg.org, qemu-devel@nongnu.org, MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>

On 06/08/2013 12:48 AM, Kevin Wolf wrote:
> Hm, yes, I was confused. :-)
> 
> Anyway, the options stay the same: Either C1 must somehow inherit the VM
> state from A on the Sheepdog level, or we must make sure to get this
> order:
> 
> 1. Switch to (read-only) snapshot A
> 2. Load the VM state
> 3. Create (writable) snapshot C1 and switch to it
> 
> This is a different order as required for qcow2 (where C1 would inherit
> the VM state from A, so our current first 1, then 3, then 2 works), but
> if we can't fix it on the Sheepdog side, we'll have to touch the core
> code of qemu. I don't like much to touch the block.c code for it, but if
> it's required to fix a bug, let's just do it.

Hmm, I found actually we can inherit A's vdi_id from C1. I've sent v3
and I think this version will fix the possible bug you pointed out and
do loadvm the way core code assumes.

Thanks,
Yuan