func GetDriveStats(major, minor uint32) (iostats IOStats, err error) {
	return readDriveStats(fmt.Sprintf("/sys/dev/block/%v:%v/stat", major, minor))
}

func readDriveStats(statsFile string) (iostats IOStats, err error) {
	stats, err := readStat(statsFile)
	if err != nil {
		return IOStats{}, err
	}
	if len(stats) < 11 {
		return IOStats{}, fmt.Errorf("found invalid format while reading %v", statsFile)
	}