pkg/driverutil.EnsureDisk: diskImageFormat is ignored for ISO mode

[AkihiroSuda]

lima/pkg/driverutil/disk.go

Lines 21 to 61 in cbe7241

	// EnsureDisk ensures that the diff disk exists with the specified size and format.
	func EnsureDisk(ctx context.Context, instDir, diskSize string, diskImageFormat image.Type) error {
	diffDisk := filepath.Join(instDir, filenames.DiffDisk)
	if _, err := os.Stat(diffDisk); err == nil || !errors.Is(err, os.ErrNotExist) {
	// disk is already ensured
	return err
	}
	diskUtil := proxyimgutil.NewDiskUtil(ctx)
	baseDisk := filepath.Join(instDir, filenames.BaseDisk)
	diskSizeInBytes, _ := units.RAMInBytes(diskSize)
	if diskSizeInBytes == 0 {
	return nil
	}
	isBaseDiskISO, err := iso9660util.IsISO9660(baseDisk)
	if err != nil {
	return err
	}
	if isBaseDiskISO {
	// Create an empty data volume (sparse)
	diffDiskF, err := os.Create(diffDisk)
	if err != nil {
	return err
	}
	err = diskUtil.MakeSparse(ctx, diffDiskF, 0)
	if err != nil {
	diffDiskF.Close()
	return fmt.Errorf("failed to create sparse diff disk %q: %w", diffDisk, err)
	}
	return diffDiskF.Close()
	}
	// Check whether to use ASIF format
	if err = diskUtil.Convert(ctx, diskImageFormat, baseDisk, diffDisk, &diskSizeInBytes, false); err != nil {
	return fmt.Errorf("failed to convert %q to a disk %q: %w", baseDisk, diffDisk, err)
	}
	return err
	}

---

diskImageFormat is ignored for ISO mode

Originally posted by @AkihiroSuda in #4327 (comment)

[ashwat287]

Hi @AkihiroSuda, is it because we are not converting ISO to any other format? I think in that case we can skip diskImageFormat.

[AkihiroSuda]

Hi @AkihiroSuda, is it because we are not converting ISO to any other format? I think in that case we can skip diskImageFormat.

No, I'm talking about the image newly created in L43.

Note that diffDisk is completely misnomer here, especially when dealing with an ISO9660 "base disk", as it is an independent disk.