Function TestFsmountLoopDevice

plugins/mount/erofs/plugin_linux_test.go:35–103

TestFsmountLoopDevice tests fsmount with loop device

(t *testing.T)

// TestFsmountLoopDevice tests fsmount with loop device
func TestFsmountLoopDevice(t *testing.T) {
	testutil.RequiresRoot(t)

	if _, err := exec.LookPath("mkfs.erofs"); err != nil {
		t.Skipf("mkfs.erofs not found: %v", err)
	}

	if !snapshotserofs.FindErofs() {
		t.Skip("erofs kernel support not available")
	}

	if !fsmount.SupportsFsmount() {
		t.Skip("fsmount syscall not available (requires Linux 5.2+)")
	}

	tempDir := t.TempDir()

	layerPath := filepath.Join(tempDir, "test.erofs")
	layerDir := filepath.Join(tempDir, "layer_dir")
	if err := os.MkdirAll(layerDir, 0755); err != nil {
		t.Fatalf("failed to create layer dir: %v", err)
	}
	if err := os.WriteFile(filepath.Join(layerDir, "test.txt"), []byte("hello"), 0644); err != nil {
		t.Fatalf("failed to write test file: %v", err)
	}

	cmd := exec.Command("mkfs.erofs", layerPath, layerDir)
	if output, err := cmd.CombinedOutput(); err != nil {
		t.Fatalf("failed to create erofs image: %v, output: %s", err, output)
	}

	loopFile, err := mount.SetupLoop(layerPath, mount.LoopParams{
		Readonly:  true,
		Autoclear: true,
	})
	if err != nil {
		t.Fatalf("failed to setup loop device: %v", err)
	}
	loopDev := loopFile.Name()
	defer func() {
		loopFile.Close()
		mount.DetachLoopDevice(loopDev)
	}()

	mountPoint := filepath.Join(tempDir, "mnt")
	if err := os.MkdirAll(mountPoint, 0755); err != nil {
		t.Fatalf("failed to create mount point: %v", err)
	}

	m := mount.Mount{
		Type:    "erofs",
		Source:  loopDev,
		Options: []string{"ro"},
	}

	err = fsmount.Fsmount(m, mountPoint)
	if err != nil {
		t.Fatalf("fsmount with loop device failed: %v", err)