libvirt users - Apr 2014 - virsh blockcommit hangs at 100%

hi,

i am trying to blockcommit a external qcow2 snapshot back into its raw 
backing file like:

sudo virsh blockcommit myDomainName vda --wait --verbose

the output just shows:

Block Commit: [100 %]

and stays like that (i waited about an hour or so...). No "Commit 
complete" message.

- explicitly passing --base and/or --top arguments makes no difference.
- did not find a related log entry in syslog and consorts

env:
- ubuntu server 14.04 x64
- libvirt-bin 1.2.2-0ubuntu13

i doubt that it just takes hours to complete after "100%", right?

any ideas? kind of a dead-end for me :/

thanks,

zyro

On 04/18/2014 08:36 AM, zyro wrote:
> hi,
> 
> i am trying to blockcommit a external qcow2 snapshot back into its raw
> backing file like:
> 
> sudo virsh blockcommit myDomainName vda --wait --verbose
> 
> the output just shows:
> 
> Block Commit: [100 %]
> 
> and stays like that (i waited about an hour or so...). No "Commit
> complete" message.
Known problem.  When libvirt first implemented blockcommit, qemu did not
support committing the active image.  Newer qemu has added that support,
but in a way that requires a tweak to libvirt to end the operation; and
libvirt has not yet been taught to make that tweak.  Patches welcome.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org