Re: [tip:tools/kvm] kvm tools, qcow: Fix copy-on-write imagecorruption

From: Pekka Enberg
Date: Fri Jul 22 2011 - 04:23:40 EST

On Thu, 21 Jul 2011, Kevin Wolf wrote:
Hm, I must have missed this patch on the KVM mailing list...

It wasn't on the list, sorry.

You should also error out before creating a new L2 table as its refcount
would have to be updated, too. On the other hand, the patch is a bit too
restrictive, because it applies the check to qcow1 which doesn't even
have a refcount table.

Oh, right, I broken QCOW1.

I'm not sure if everyone is aware of it, so another hint: Now that you
can't grow qcow2 any more, you might find it useful to use qemu-img
create -f qcow2 -o preallocation=metadata, so that all clusters are
already present and you don't get random failures.

Yup, I'm aware that you can't grow images anymore. The patch was meant as a stop-gap measure while I'm hacking on refcount table support.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at