[Libguestfs] [PATCH 2/2] nbd: Add new qemu:joint-allocation metadata context

[Nir Soffer]

On Thu, Jun 10, 2021 at 2:52 AM Nir Soffer <nsoffer at redhat.com> wrote:
>
> On Wed, Jun 9, 2021 at 9:01 PM Eric Blake <eblake at redhat.com> wrote:

I posted a work in progress patch implementing support for
qemu:joint-allocaition
in oVirt:
https://gerrit.ovirt.org/c/ovirt-imageio/+/115197

The most important part is the nbd client:
https://gerrit.ovirt.org/c/ovirt-imageio/+/115197/1/daemon/ovirt_imageio/_internal/nbd.py

With this our tests pass with qemu-nbd build with Eric patch:
https://gerrit.ovirt.org/c/ovirt-imageio/+/115197/1/daemon/test/client_test.py

We may need to use qemu:joint-allocation only for qcow2 images, and
base:allocation
for raw images, because allocation depth reporting is not correct for
raw images. Since
we control the qemu-nbd in both cases this should not be an issue. But
it would be
better if allocation depth would work for any kind of image, and we always use
qemu:joint-allocation.

Nir