plop.py

def get_scratch_devices2(remote):
    """
    Extract the list of free block device from a host
    """
    used_block_devices = get_used_block_devices(remote)
    used_block_devices.append(get_root_device(remote))
    translated_uuids = translate_block_UUID(used_block_devices)
    expanded_block_devices = expand_dm_devices(translated_uuids)
    translated_block_devices = translate_block_devices_path(expanded_block_devices)
    final_used_block_devices = partitions_to_block_device(translated_block_devices)

    all_block_devices = translate_block_devices_path(expand_dm_devices(get_block_devices()))
    final_all_block_devices = partitions_to_block_device(all_block_devices)

    free_block_devices = get_free_block_devices(final_all_block_devices, final_used_block_devices)

    # If we didn't got a single used device,
    if len(free_block_devices) == len(final_all_block_devices):
        log.error("All block devices are seen as free ! That will surely damage data")
        # We return an empty list to avoid listing a mis-detected used device
        return []

    return free_block_devices