[sheepdog] [PATCH 2/2] sheepdog: support 'qemu-img snapshot -a'

[Liu Yuan]

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