t.Fatal(err)
	}

	if err = os.WriteFile(pathJoin(rootPath, minioMetaBucket, formatConfigFile), b, os.FileMode(0o644)); err != nil {
		t.Fatal(err)
	}

	formatData, _, err := formatErasureMigrate(rootPath)
	if err != nil {
		t.Fatal(err)
	}

	migratedVersion, err := formatGetBackendErasureVersion(formatData)
	if err != nil {
		t.Fatal(err)
	}

}

// Migrates all previous versions to latest version of `format.json`,
// this code calls migration in sequence, such as V1 is migrated to V2
// first before it V2 migrates to V3.n
func formatErasureMigrate(export string) ([]byte, fs.FileInfo, error) {
	formatPath := pathJoin(export, minioMetaBucket, formatConfigFile)
	formatData, formatFi, err := xioutil.ReadFileWithFileInfo(formatPath)
	if err != nil {

		s.walkMu = &sync.Mutex{}
		s.walkReadMu = &sync.Mutex{}
	}

	if cleanUp {
		bgFormatErasureCleanupTmp(s.drivePath) // cleanup any old data.
	}

	formatData, formatFi, err := formatErasureMigrate(s.drivePath)
	if err != nil && !errors.Is(err, os.ErrNotExist) {
		if os.IsPermission(err) {
			return s, errDiskAccessDenied
		} else if isSysErrIO(err) {
			return s, errFaultyDisk
		}
		return s, err