Strip W_OK from Access mask.

unionfs/unionfs.go

@@ -458,11 +458,12 @@ func (me *UnionFs) Chmod(name string, mode uint32) (code fuse.Status) {
 }
 
 func (me *UnionFs) Access(name string, mode uint32) (code fuse.Status) {
+	// We always allow writing.
+	mode = mode &^ fuse.W_OK
 	r := me.getBranch(name)
 	if r.branch >= 0 {
 		return me.fileSystems[r.branch].Access(name, mode)
 	}
-
 	return fuse.ENOENT
 }
 

unionfs/unionfs_test.go

@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"fmt"
 	"log"
+	"syscall"
 	"testing"
 	"time"
 )
@@ -420,6 +421,23 @@ func TestWritableDir(t *testing.T) {
 	}
 }
 
+func TestWriteAccess(t *testing.T) {
+	t.Log("TestWriteAccess")
+	wd, clean := setupUfs(t)
+	defer clean()
+
+	fn := wd + "/ro/file"
+	// No write perms.
+	err := ioutil.WriteFile(fn, []byte("foo"), 0444)
+	CheckSuccess(err)
+
+	errno := syscall.Access(wd + "/mount/file", fuse.W_OK)
+	if errno != 0 {
+		err = os.Errno(errno)
+		CheckSuccess(err)
+	}
+}
+
 func TestTruncate(t *testing.T) {
 	t.Log("TestTruncate")
 	wd, clean := setupUfs(t)