Unmount script on zfs-encrypted example fails at unload-key

[Bert-Proesmans]

Error cannot open 'root': dataset does not exist when executing the disko unmount script on the example configuration zfs-encrypted-root.nix.

Reproduction

1. Deploy the zfs-encrypted-root.nix configuration on top of a (virtual) disk
   • Use the diskoScript attribute script to format+mount
2. Cleanup the disko managed mounts
   • Use the unmount attribute script to unmount
3. Observe error message after the zfs unload-key command

Expected to happen

Key for dataset zroot/root is sucessfully unloaded IF it was previously loaded.

What happens

Command zfs unload-key root fails because the filesystem argument is not zroot/root (poolname + dataset path).

Possible fix

I think the filesystem name argument for zfs unload-key has to be changed to become the poolname + dataset path. AKA "${config._parent.name}/${config.name}" ?
RELATED; The zfs load-key in the mount script is also broken probably? This flies under the radar (I guess) due to testing sequence "create" + "mount"; where "create" already does correct encryption setup.

disko/lib/types/zfs_volume.nix

Lines 91 to 100 in 67ff980

	_unmount = diskoLib.mkUnmountOption {
	inherit config options;
	default = {
	dev = ''
	${lib.optionalString (
	config.options.keylocation or "none" != "none"
	) "zfs unload-key ${config.name}"}
	${config.content._unmount.dev or ""}
	'';