Oops, mounts shouldn't be a list, should be attrs.

lib/fudo/host-filesystems.nix

@@ -12,7 +12,7 @@ in {
           (fs: opts: { filesystem = fs; opts = opts; })
           host-filesystems;
 
-        mounts = concatMap
+        mounts = builtins.listToAttrs (concatMap
           (fs: mapAttrsToList
             (mp: mp-opts:
               nameValuePair "${fs.filesystem}-${mp}-mount" {
@@ -25,7 +25,7 @@ in {
                 requires = [ "${fs.filesystem}-decrypt.service" ];
               })
             fs.opts.mountpoints)
-          filesystems;
+          filesystems);
       in mounts;
 
       services = mapAttrs' (filesystem-name: opts:

lib/types/host.nix

@@ -15,6 +15,8 @@ rec {
           type = listOf str;
           description = "List of filesystem options specific to this mountpoint (eg: subvol).";
         };
+
+        # TODO: Access control. Group? List of users?
       };
     };
   in {