nodefs: add MemRegularFile.Flush

nodefs/bridge.go

@@ -728,6 +728,7 @@ func (b *rawBridge) Flush(cancel <-chan struct{}, input *fuse.FlushIn) fuse.Stat
 	if fl, ok := f.file.(FileFlusher); ok {
 		return errnoToStatus(fl.Flush(&fuse.Context{Caller: input.Caller, Cancel: cancel}))
 	}
+	// XXX should return OK to reflect r/o filesystem?
 	return fuse.ENOTSUP
 }
 

nodefs/mem.go

@@ -22,6 +22,7 @@ type MemRegularFile struct {
 var _ = (Opener)((*MemRegularFile)(nil))
 var _ = (Getattrer)((*MemRegularFile)(nil))
 var _ = (Reader)((*MemRegularFile)(nil))
+var _ = (Flusher)((*MemRegularFile)(nil))
 
 func (f *MemRegularFile) Open(ctx context.Context, flags uint32) (fh FileHandle, fuseFlags uint32, errno syscall.Errno) {
 	if flags&(syscall.O_RDWR) != 0 || flags&syscall.O_WRONLY != 0 {
@@ -38,6 +39,10 @@ func (f *MemRegularFile) Getattr(ctx context.Context, fh FileHandle, out *fuse.A
 	return OK
 }
 
+func (f *MemRegularFile) Flush(ctx context.Context, fh FileHandle) syscall.Errno {
+	return 0
+}
+
 func (f *MemRegularFile) Read(ctx context.Context, fh FileHandle, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) {
 	end := int(off) + len(dest)
 	if end > len(f.Data) {

nodefs/mem_test.go

@@ -6,7 +6,6 @@ package nodefs
 
 import (
 	"context"
-	"io/ioutil"
 	"os"
 	"syscall"
 	"testing"
@@ -54,11 +53,23 @@ func TestDataFile(t *testing.T) {
 	})
 	defer clean()
 
-	c, err := ioutil.ReadFile(mntDir + "/file")
+	fd, err := syscall.Open(mntDir+"/file", syscall.O_RDONLY, 0)
 	if err != nil {
-		t.Fatalf("ReadFile: %v", err)
+		t.Fatalf("Open: %v", err)
 	}
-	if got := string(c); got != want {
+
+	var buf [1024]byte
+	n, err := syscall.Read(fd, buf[:])
+	if err != nil {
+		t.Errorf("Read: %v", err)
+	}
+
+	if err := syscall.Close(fd); err != nil {
+		t.Errorf("Close: %v", err)
+	}
+
+	got := string(buf[:n])
+	if got != want {
 		t.Errorf("got %q want %q", got, want)
 	}
 }