>> Why not stick to slaves/ like the device mapper? > > Because: > > /** > * bd_link_disk_holder - create symlinks between holding disk and slave > bdev > * @bdev: the claimed slave bdev > * @disk: the holding disk > * > * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. > * > > Not sure _why_ it's there, but it is there. Fair enough