Don't discard ENOSYS from DefaultFile.

fuse/defaultfile.go

@@ -23,7 +23,7 @@ func (f *DefaultFile) String() string {
 }
 
 func (f *DefaultFile) Read(buf []byte, off int64) (ReadResult, Status) {
-	return &ReadResultData{}, ENOSYS
+	return nil, ENOSYS
 }
 
 func (f *DefaultFile) Write(data []byte, off int64) (uint32, Status) {

fuse/defaultread_test.go

+package fuse
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+	"testing"
+)
+
+var _ = log.Println
+
+type DefaultReadFS struct {
+	DefaultFileSystem
+	size  uint64
+	exist bool
+}
+
+func (fs *DefaultReadFS) GetAttr(name string, context *Context) (*Attr, Status) {
+	if name == "" {
+		return &Attr{Mode: S_IFDIR | 0755}, OK
+	}
+	if name == "file" {
+		return &Attr{Mode: S_IFREG | 0644, Size: fs.size}, OK
+	}
+	return nil, ENOENT
+}
+
+func (fs *DefaultReadFS) Open(name string, f uint32, context *Context) (File, Status) {
+	return &DefaultFile{}, OK
+}
+
+
+func defaultReadTest() (root string, cleanup func()) {
+	fs := &NotifyFs{}
+	var err error
+	dir, err := ioutil.TempDir("", "go-fuse")
+	CheckSuccess(err)
+	pathfs := NewPathNodeFs(fs, nil)
+	state, _, err := MountNodeFileSystem(dir, pathfs, nil)
+	CheckSuccess(err)
+	state.Debug = VerboseTest()
+	go state.Loop()
+	
+	return dir, func() {
+		state.Unmount()
+		os.Remove(dir)
+	}
+}
+
+func TestDefaultRead(t *testing.T) {
+	root, clean := defaultReadTest()
+	defer clean()
+
+	_, err := ioutil.ReadFile(root + "/file")
+	if err == nil {
+		t.Fatal("should have failed read.")
+	}
+}

fuse/opcode.go

@@ -283,7 +283,7 @@ func doRead(state *MountState, req *request) {
 	if fd, ok := req.readResult.(*ReadResultFd); ok {
 		req.fdData = fd
 		req.flatData = nil
-	} else if req.readResult != nil {
+	} else if req.readResult != nil && req.status.Ok() {
 		req.flatData, req.status = req.readResult.Bytes(buf)
 	}
 }