Write replies to the kernel.

connection.go

@@ -237,14 +237,19 @@ func (c *Connection) ReadOp() (op fuseops.Op, err error) {
 			fuseID uint64,
 			replyMsg []byte,
 			opErr error) (err error) {
+			// Make sure we destroy the message, as required by
+			// fuseshim.Connection.ReadMessage.
+			defer m.Destroy()
+
 			// Clean up state for this op.
 			c.finishOp(m.Hdr.Opcode, m.Hdr.Unique)
 
 			// Send the reply to the kernel.
-			panic("TODO")
-
-			// Destroy the message, as required by fuseshim.Connection.ReadMessage.
-			m.Destroy()
+			err = c.wrapped.WriteToKernel(replyMsg)
+			if err != nil {
+				err = fmt.Errorf("WriteToKernel: %v", err)
+				return
+			}
 
 			return
 		}

internal/fuseshim/fuse.go

@@ -1061,7 +1061,7 @@ func errorString(err error) string {
 	return err.Error()
 }
 
-func (c *Conn) writeToKernel(msg []byte) error {
+func (c *Conn) WriteToKernel(msg []byte) error {
 	out := (*fusekernel.OutHeader)(unsafe.Pointer(&msg[0]))
 	out.Len = uint32(len(msg))
 
@@ -1072,7 +1072,7 @@ func (c *Conn) writeToKernel(msg []byte) error {
 }
 
 func (c *Conn) respond(msg []byte) {
-	c.writeToKernel(msg)
+	c.WriteToKernel(msg)
 }
 
 type notCachedError struct{}
@@ -1097,7 +1097,7 @@ var (
 //
 // A returned ENOENT is translated to a friendlier error.
 func (c *Conn) sendInvalidate(msg []byte) error {
-	switch err := c.writeToKernel(msg); err {
+	switch err := c.WriteToKernel(msg); err {
 	case syscall.ENOENT:
 		return ErrNotCached
 	default: