Re: Is this a bug in qemu-img?

walt
2008-11-23T17:30:08Z

On Sun, 23 Nov 2008, Avi Kivity wrote:

> walt wrote:
> > I do a fresh install of Windows vista on qcow2 which works
> > perfectly. Thereafter I use that image as a backing file
> > to make all kinds of updates to Vista, and all that works
> > perfectly too.
> >
> > Then I use 'qemu-img commit' to commit all the changes I've
> > made to Vista. The problem is that the updated base image
> > doesn't work quite right if I try to run Vista from it --
> > there are minor malfunctions which indicate that the commit
> > was incomplete or maybe just wrong.
>
> What's your sequence of commands? Are you using -snapshot?

No, not using -snapshot anywhere. I'm not sure how much detail
you want, but here's from the beginning:

#qemu-img create -f qcow2 vista 20G
#qemu-system-x86_64 -m 2048 -cdrom vistasp1.iso vista
[install vista without updating and exit]
#qemu-img create -f qcow2 -b vista vista.delta
#qemu-system-x86_64 -m 2048 vista.delta
[update vista with all the recent patches and exit]

Everything above works perfectly. I can reboot vista,
check for new updates, create user accounts, all the
normal stuff. Now comes the trouble:

#qemu-img commit vista.delta [takes >1 hour]

Now, IIUC the base image vista should be entirely
useable by itself, i.e. I can delete vista.delta
and everyting should still work correctly?

But it doesn't. For example, when I boot vista and
try to look for windows updates, the updates page is
almost blank and completely non-functional. There
may be other problems too, but I haven't bothered
to look.

BTW, I've been through the same steps twice and
get the same results, so I don't think it's flakey
hardware. OTOH today is a new day, so I'll try it
again to triple check.

Any thoughts?

Thanks.