similar to: virsh can't support VM offline blockcommit

Hi Kashyap Chamarthy: thank you very much for answer my question: 一： lead to VM filesystem becoming read-only 1： test case it lead to VM filesystem becoming read-only test case as follows: we want to snapshot for VM , to obtain VM incremental data，and use virsh blockcommit，qemu-img commit，qemu-img rebase to shorten snapshot chain. Details are as follows（when VM running state， we perform the