Function createEmptyFSImage

tests/dmflakey/dmflakey.go:296–340

createEmptyFSImage creates empty filesystem on dataStorePath folder with default size - 10 GiB.

(imgPath string, fsType FSType, mkfsOpt string)

// createEmptyFSImage creates empty filesystem on dataStorePath folder with
// default size - 10 GiB.
func createEmptyFSImage(imgPath string, fsType FSType, mkfsOpt string) error {
	if err := validateFSType(fsType); err != nil {
		return err
	}

	mkfs, err := exec.LookPath(fmt.Sprintf("mkfs.%s", fsType))
	if err != nil {
		return fmt.Errorf("failed to ensure mkfs.%s: %w", fsType, err)
	}

	if _, err := os.Stat(imgPath); err == nil {
		return fmt.Errorf("failed to create image because %s already exists", imgPath)
	}

	if err := os.MkdirAll(path.Dir(imgPath), 0600); err != nil {
		return fmt.Errorf("failed to ensure parent directory %s: %w", path.Dir(imgPath), err)
	}

	f, err := os.Create(imgPath)
	if err != nil {
		return fmt.Errorf("failed to create image %s: %w", imgPath, err)
	}

	if err = func() error {
		defer f.Close()

		return f.Truncate(defaultImgSize)
	}(); err != nil {
		return fmt.Errorf("failed to truncate image %s with %v bytes: %w",
			imgPath, defaultImgSize, err)
	}

	args := []string{imgPath}
	if mkfsOpt != "" {
		splitArgs := strings.Split(mkfsOpt, " ")
		args = append(splitArgs, imgPath)
	}

	output, err := exec.Command(mkfs, args...).CombinedOutput()
	if err != nil {
		return fmt.Errorf("failed to mkfs on %s (%s %v) (out: %s): %w",
			imgPath, mkfs, args, string(output), err)
	}
	return nil
}

// validateFSType validates the fs type input.
func validateFSType(fsType FSType) error {