Possibly. You didn't attach the state in the XML along with the 'info block' output and also didn't check it prior to issuing 'virsh change-media', so I'm not sure whether the root cause is similar.
Possibly. You didn't attach the state in the XML along with the 'info block' output and also didn't check it prior to issuing 'virsh change-media', so I'm not sure whether the root cause is similar.