Comment 7 for bug 1782714

If that is the case, could you try with a volume that has a different attached_mode? As I believe we may have a bug there.

It looks like we are redoing all attachments as "rw" [1]:

            for attachment in volume_attachments:
                LOG.debug('Re-attaching: %s', attachment)
                # This is just a db state toggle, the volume is actually
                # already attach and in-use, new attachment flow won't allow
                # this
                rpcapi.attach_volume(ctxt, volume,
                                     attachment.instance_uuid,
                                     attachment.attached_host,
                                     attachment.mountpoint,
                                     'rw')

[1]: https://github.com/openstack/cinder/blob/37f2bdcdec85f27651b91a9a2d0fddb66e7bfe8a/cinder/volume/manager.py#L2312-L2316