Make another snapshot of this into dirName.

def copy(self, path):
        """ Make another snapshot of this into dirName. """
        directoryPath = os.path.dirname(path)
        if not os.path.exists(directoryPath):
            os.makedirs(directoryPath)

        logger.debug('Create copy of %s in %s', os.path.basename(path), directoryPath)

        with self._snapshot() as source, _Directory(directoryPath) as dest:
            dest.SNAP_CREATE_V2(
                flags=BTRFS_SUBVOL_RDONLY,
                name=str(os.path.basename(path)),
                fd=source.fd,
            )

        with SnapShot(path) as destShot:
            flags = destShot.SUBVOL_GETFLAGS()
            destShot.SUBVOL_SETFLAGS(flags=flags.flags & ~BTRFS_SUBVOL_RDONLY)

            destShot.SET_RECEIVED_SUBVOL(
                uuid=self.received_uuid or self.uuid,
                stransid=self.sent_gen or self.current_gen,
                stime=timeOrNone(self.info.stime) or timeOrNone(self.info.ctime) or 0,
                flags=0,
            )

            destShot.SUBVOL_SETFLAGS(flags=flags.flags)