[libvirt] [PATCH 0/7] Add support for qcow2 backing files to sVirt

[Mark McLoughlin <markmc redhat com>]

Hey,
        https://bugzilla.redhat.com/497131 shows that sVirt cannot
currently handle qcow2 files with a backing store. Because we do
not re-label the backing store, qemu cannot read it.

        The fix is fairly straightforward - when we go to re-label
a file, check its header and if it has a backing store, re-label
that too.

        Most of this series involves moving the header probing code
from the storage driver into libvirt_util so that the security
driver can use it.

Cheers,
Mark.