ctx, cancel := context.WithTimeout(ctx, timeout)
		defer cancel()

		return saveConfig(ctx, store, pathJoin(bucketMetaPrefix, name), buf.Bytes())
	}
	defer save(name+".bkp", 5*time.Second) // Keep a backup as well

	// drive timeout by default is 2 minutes, we do not need to wait longer.
	return save(name, time.Minute)
}

// dataUsageCacheVer indicates the cache version.