Function TestFSMountsOverlayWithEROFSDevices

internal/fsview/mount_test.go:259–359

(t *testing.T)

}

func TestFSMountsOverlayWithEROFSDevices(t *testing.T) {
	skipIfNoMkfsErofs(t)

	tc := tartest.TarContext{}.WithModTime(time.Now().UTC())

	// Layer 1 (bottom): regular files including ones that will be hidden
	layer1Path := makeEROFSFromTar(t, tartest.TarAll(
		tc.Dir("dir", 0755),
		tc.File("dir/file1.txt", []byte("file1 content"), 0644),
		tc.File("dir/file2.txt", []byte("file2 content"), 0644),
		tc.File("dir/file5.txt", []byte("file5 content"), 0644),
		tc.Dir("opaquedir", 0755),
		tc.File("opaquedir/old.txt", []byte("old content"), 0644),
	))

	// Layer 2 (top): new files, a whiteout for file5.txt, and an opaque opaquedir.
	// AUFS-style markers (.wh.*) are converted by mkfs.erofs --aufs to
	// overlay-native whiteouts (char dev 0:0) and opaque xattrs.
	layer2Path := makeEROFSFromTar(t, tartest.TarAll(
		tc.Dir("dir", 0755),
		tc.File("dir/file3.txt", []byte("file3 content"), 0644),
		tc.File("dir/.wh.file5.txt", []byte{}, 0644),
		tc.Dir("opaquedir", 0755),
		tc.File("opaquedir/.wh..wh..opq", []byte{}, 0644),
		tc.File("opaquedir/new.txt", []byte("new content"), 0644),
	))

	// Merge with layer1 as lower (first arg) and layer2 as upper (last arg)
	// so whiteouts in layer2 apply to layer1.
	metaPath := mergeEROFSLayers(t, layer1Path, layer2Path)

	// Create upper directory with additional and override files
	upperDir := filepath.Join(t.TempDir(), "upper")
	if err := os.MkdirAll(filepath.Join(upperDir, "dir"), 0755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(upperDir, "dir", "file4.txt"), []byte("file4 content"), 0644); err != nil {
		t.Fatal(err)
	}
	// Override file1.txt from lower layer
	if err := os.WriteFile(filepath.Join(upperDir, "dir", "file1.txt"), []byte("file1 override"), 0644); err != nil {
		t.Fatal(err)
	}

	v, err := fsview.FSMounts([]mount.Mount{
		{
			Type:    "erofs",
			Source:  metaPath,
			Options: []string{"ro", "device=" + layer1Path, "device=" + layer2Path},
		},
		{
			Type:   "format/overlay",
			Source: "overlay",
			Options: []string{
				"upperdir=" + upperDir,
				"lowerdir={{ mount 0 }}",
			},
		},