Make hiding the READONLY link switchable in AutoUnionFs.

example/autounionfs/main.go

@@ -17,6 +17,9 @@ func main() {
 	branchcache_ttl := flag.Float64("branchcache_ttl", 5.0, "Branch cache TTL in seconds.")
 	deldirname := flag.String(
 		"deletion_dirname", "GOUNIONFS_DELETIONS", "Directory name to use for deletions.")
+	hide_readonly_link := flag.Bool("hide_readonly_link", true,
+		"Hides READONLY link from the top mountpoints. " +
+		"Enabled by default.")
 	flag.Parse()
 
 	if *version {
@@ -45,6 +48,7 @@ func main() {
 		PathNodeFsOptions: fuse.PathNodeFsOptions{
 			ClientInodes: *hardlinks,
 		},
+		HideReadonly:     *hide_readonly_link,
 	}
 
 	fmt.Printf("AutoUnionFs - Go-FUSE Version %v.\n", fuse.Version())

example/unionfs/main.go

@@ -21,6 +21,7 @@ func main() {
 	branchcache_ttl := flag.Float64("branchcache_ttl", 5.0, "Branch cache TTL in seconds.")
 	deldirname := flag.String(
 		"deletion_dirname", "GOUNIONFS_DELETIONS", "Directory name to use for deletions.")
+
 	flag.Parse()
 	if len(flag.Args()) < 2 {
 		fmt.Println("Usage:\n  unionfs MOUNTPOINT RW-DIRECTORY RO-DIRECTORY ...")

unionfs/autounion.go

@@ -44,6 +44,9 @@ type AutoUnionFsOptions struct {
 
 	// If set, run updateKnownFses() after mounting.
 	UpdateOnMount bool
+
+	// If set hides the _READONLY file.
+	HideReadonly bool
 }
 
 const (
@@ -57,6 +60,9 @@ const (
 )
 
 func NewAutoUnionFs(directory string, options AutoUnionFsOptions) *AutoUnionFs {
+	if options.HideReadonly {
+		options.HiddenFiles = append(options.HiddenFiles, _READONLY)
+	}
 	a := new(AutoUnionFs)
 	a.knownFileSystems = make(map[string]knownFs)
 	a.nameRootMap = make(map[string]string)

unionfs/autounion_test.go

@@ -24,6 +24,7 @@ var testAOpts = AutoUnionFsOptions{
 		AttrTimeout:     entryTtl,
 		NegativeTimeout: 0,
 	},
+	HideReadonly: true,
 }
 
 func WriteFile(name string, contents string) {

unionfs/unionfs.go

@@ -14,6 +14,7 @@ import (
 	"time"
 )
 
+
 func filePathHash(path string) string {
 	dir, base := filepath.Split(path)
 
@@ -65,6 +66,9 @@ type UnionFs struct {
 	// A file -> branch cache.
 	branchCache *TimedCache
 
+	// Map of files to hide.
+	hiddenFiles map[string]bool
+
 	options *UnionFsOptions
 	nodeFs  *fuse.PathNodeFs
 }
@@ -73,6 +77,7 @@ type UnionFsOptions struct {
 	BranchCacheTTL   time.Duration
 	DeletionCacheTTL time.Duration
 	DeletionDirName  string
+	HiddenFiles      []string
 }
 
 const (
@@ -96,6 +101,12 @@ func NewUnionFs(fileSystems []fuse.FileSystem, options UnionFsOptions) *UnionFs
 		func(n string) (interface{}, bool) { return g.getBranchAttrNoCache(n), true },
 		options.BranchCacheTTL)
 	g.branchCache.RecurringPurge()
+
+	g.hiddenFiles = make(map[string]bool)
+	for _, name := range options.HiddenFiles {
+		g.hiddenFiles[name] = true
+	}
+
 	return g
 }
 
@@ -659,7 +670,8 @@ func (me *UnionFs) Create(name string, flags uint32, mode uint32, context *fuse.
 }
 
 func (me *UnionFs) GetAttr(name string, context *fuse.Context) (a *fuse.Attr, s fuse.Status) {
-	if name == _READONLY {
+	_, hidden := me.hiddenFiles[name]
+	if hidden {
 		return nil, fuse.ENOENT
 	}
 	if name == _DROP_CACHE {
@@ -778,8 +790,9 @@ func (me *UnionFs) OpenDir(directory string, context *fuse.Context) (stream chan
 	}
 	if directory == "" {
 		delete(results, me.options.DeletionDirName)
-		// HACK.
-		delete(results, _READONLY)
+		for name, _ := range me.hiddenFiles {
+			delete(results, name)
+		}
 	}
 
 	stream = make(chan fuse.DirEntry, len(results))

unionfs/unionfs_test.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strings"
 	"syscall"
 	"testing"
 	"time"
@@ -25,6 +26,7 @@ var testOpts = UnionFsOptions{
 	DeletionCacheTTL: entryTtl,
 	DeletionDirName:  "DELETIONS",
 	BranchCacheTTL:   entryTtl,
+	HiddenFiles: []string{ "hidden" },
 }
 
 func freezeRo(dir string) {
@@ -37,6 +39,8 @@ func freezeRo(dir string) {
 	CheckSuccess(err)
 }
 
+// Creates 3 directories on a temporary dir: /mnt with the overlayed
+// (unionfs) mount, rw with modifiable data, and ro on the bottom.
 func setupUfs(t *testing.T) (workdir string, cleanup func()) {
 	// Make sure system setting does not affect test.
 	syscall.Umask(0)
@@ -742,6 +746,8 @@ func TestUnionFsRemoveAll(t *testing.T) {
 	}
 }
 
+// Warning: test fails under coreutils < 8.0 because of non-posix behaviour
+// of the "rm" tool -- which relies on behaviour that doesn't work in fuse.
 func TestUnionFsRmRf(t *testing.T) {
 	wd, clean := setupUfs(t)
 	defer clean()
@@ -757,6 +763,10 @@ func TestUnionFsRmRf(t *testing.T) {
 
 	bin, err := exec.LookPath("rm")
 	CheckSuccess(err)
+	command := fmt.Sprintf("%s -f %s/mnt/dir", bin, wd);
+	log.Printf("Command: %s", command)
+	names, _ := Readdirnames(wd + "/mnt/dir")
+	log.Printf("Contents of %s/mnt/dir: %s", wd, strings.Join(names, ", "))
 	cmd := exec.Command(bin, "-rf", wd+"/mnt/dir")
 	err = cmd.Run()
 	if err != nil {
@@ -769,7 +779,7 @@ func TestUnionFsRmRf(t *testing.T) {
 		}
 	}
 
-	names, err := Readdirnames(wd + "/rw/DELETIONS")
+	names, err = Readdirnames(wd + "/rw/DELETIONS")
 	CheckSuccess(err)
 	if len(names) != 3 {
 		t.Fatal("unexpected names", names)
@@ -1116,3 +1126,27 @@ func TestUnionFsPromoteDirTimeStamp(t *testing.T) {
 		t.Errorf("Changed mode ro: %v, rw: %v", fRo.Mode(), fRw.Mode())
 	}
 }
+
+func TestUnionFsCheckHiddenFiles(t *testing.T) {
+	wd, clean := setupUfs(t)
+	defer clean()
+
+	err := ioutil.WriteFile(wd+"/ro/hidden", []byte("bla"), 0644)
+	CheckSuccess(err)
+	err = ioutil.WriteFile(wd+"/ro/not_hidden", []byte("bla"), 0644)
+	CheckSuccess(err)
+	freezeRo(wd + "/ro")
+
+	fi, _ := os.Lstat(wd + "/mnt/hidden")
+	if fi != nil {
+		t.Fatal("Lstat() should have failed", fi)
+	}
+	_, err = os.Lstat(wd + "/mnt/not_hidden")
+	CheckSuccess(err)
+
+	names, err := Readdirnames(wd + "/mnt")
+	CheckSuccess(err)
+	if len(names) != 1 || names[0] != "not_hidden" {
+		t.Fatal("unexpected names", names)
+	}
+}