On 01/30/2012 10:33 AM, Hu Tao wrote:
> I cannot reproduce this with a 100G qcow2 image (created with
> "qemu-img create scsi.qcow2 100G" just before launching the host),
> with a partition starting at sector 2048 and extending to the end of
> the disk. mkfs (ext4) takes less than 1 minute and extends the
> qcow2 file to a little less than 2 gigs.
I've re-tested today, with host kernel 2.6.35.6-45.fc14.x86_64,
2.6.32-71.el6.x86_64, 3.1.0 and 3.3.0-rc1+, qemu version and guest
configuration remain the same, including guest kernel. It apears
that the problem appears only when the host kernel version is 3.1.0.
There are two parts in the bug:
1) I/O cancellation doesn't actually cancel anything on qcow2 (and maybe
others) since the coroutine transition. This makes exception handling
basically unusable in the virtio-scsi guest driver. I have been working
on this but I don't have patches ready for testing yet.
2) Something unknown in the kernel is causing writes to take a longer
time than usual. This appears to be a problem only with 3.1.0 guest
kernels.
I think we can wait until (1) causes problems elsewhere. Thanks for
testing!
Paolo
