switch cache.Info.Name {
	case "", dataUsageRoot:
		return cache, errors.New("internal error: root scan attempted")
	}
	updatePath, closeDisk := globalScannerMetrics.currentPathUpdater(basePath, cache.Info.Name)
	defer closeDisk()

	s := folderScanner{
		root:                  basePath,
		getSize:               getSize,
		oldCache:              cache,