improve error handling

Signed-off-by: Zen <[email protected]>

Author: desultory

src/ugrd/fs/mounts.py

@@ -291,7 +291,8 @@ def autodetect_root_luks(self, mount_loc, mapped_name, luks_mount) -> None:
     self.logger.debug("[%s] LUKS mount info: %s" % (mapped_name, luks_mount))
     if luks_mount.get('type') != 'crypto_LUKS':
         if not luks_mount.get('uuid'):  # No uuid will be defined if there are detached headers
-            self.logger.error("[%s] Unknown device mapper slave type: %s" % (self._dm_info[mapped_name]['slaves'][0], luks_mount.get('type')))
+            if self['cryptsetup'][self._dm_info[mapped_name]['name']].get('header_fiile'):
+                raise ValueError("[%s] Unknown LUKS mount type, if using detached headers, specify 'header_file': %s" % (mount_loc.name, luks_mount.get('type')))
         else:  # If there is some uuid and it's not LUKS, that's a problem
             raise RuntimeError("[%s] Unknown device mapper slave type: %s" % (self._dm_info[mapped_name]['slaves'][0], luks_mount.get('type')))