{ config, lib, ... }: let btrfsDevices = lib.unique ( lib.mapAttrsToList (_name: value: value.device) ( lib.filterAttrs (_name: value: value.fsType == "btrfs") config.fileSystems ) ); in { services.btrfs.autoScrub = { enable = btrfsDevices != [ ]; fileSystems = btrfsDevices; }; }