Merge pull request #3391 from nirs/round-up-disk-size

disk: Round up disk size to 512 bytes

Author: jandubois

pkg/nativeimgutil/nativeimgutil.go

@@ -23,6 +23,17 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+// Disk image size must be aigned to sector size. Qemu block layer is rounding
+// up the size to 512 bytes. Apple virtualization framework reject disks not
+// aligned to 512 bytes.
+const sectorSize = 512
+
+// RoundUp rounds size up to sectorSize.
+func RoundUp(size int) int {
+	sectors := (size + sectorSize - 1) / sectorSize
+	return sectors * sectorSize
+}
+
 // CreateRawDataDisk creates an empty raw data disk.
 func CreateRawDataDisk(dir string, size int) error {
 	dataDisk := filepath.Join(dir, filenames.DataDisk)
@@ -34,13 +45,15 @@ func CreateRawDataDisk(dir string, size int) error {
 		return err
 	}
 	defer f.Close()
-	return f.Truncate(int64(size))
+	roundedSize := RoundUp(size)
+	return f.Truncate(int64(roundedSize))
 }
 
 // ResizeRawDataDisk resizes a raw data disk.
 func ResizeRawDataDisk(dir string, size int) error {
 	dataDisk := filepath.Join(dir, filenames.DataDisk)
-	return os.Truncate(dataDisk, int64(size))
+	roundedSize := RoundUp(size)
+	return os.Truncate(dataDisk, int64(roundedSize))
 }
 
 // ConvertToRaw converts a source disk into a raw disk.

pkg/nativeimgutil/nativeimgutil_test.go

@@ -13,6 +13,24 @@ import (
 	"gotest.tools/v3/assert"
 )
 
+func TestRoundUp(t *testing.T) {
+	tests := []struct {
+		Size    int
+		Rounded int
+	}{
+		{0, 0},
+		{1, 512},
+		{511, 512},
+		{512, 512},
+		{123456789, 123457024},
+	}
+	for _, tc := range tests {
+		if RoundUp(tc.Size) != tc.Rounded {
+			t.Errorf("expected %d, got %d", tc.Rounded, tc.Size)
+		}
+	}
+}
+
 func createImg(name, format, size string) error {
 	return exec.Command("qemu-img", "create", name, "-f", format, size).Run()
 }