Merge branch 'master' of github.com:coreos/torus

cmd/torusblk/nbd.go

@@ -24,18 +24,29 @@ var (
 		Short: "serve a block volume over the NBD protocol",
 		Run:   nbdServeAction,
 	}
+)
 
+var (
 	serveListenAddress string
+	detachDevice       string
 )
 
 func init() {
 	rootCommand.AddCommand(nbdCommand)
+	rootCommand.AddCommand(nbdServeCommand)
 
+	nbdCommand.Flags().StringVarP(&detachDevice, "detach", "d", "", "detach an NBD device from a block volume. (e.g. torsublk nbd -d /dev/nbd0)")
 	nbdServeCommand.Flags().StringVarP(&serveListenAddress, "listen", "l", "0.0.0.0:10809", "nbd server listen address")
-	rootCommand.AddCommand(nbdServeCommand)
 }
 
 func nbdAction(cmd *cobra.Command, args []string) {
+	if len(detachDevice) > 0 && len(args) == 0 {
+		if err := nbd.Detach(detachDevice); err != nil {
+			die("failed to detach: %v", err)
+		}
+		os.Exit(0)
+	}
+
 	if len(args) != 1 && len(args) != 2 {
 		cmd.Usage()
 		os.Exit(1)
@@ -116,7 +127,7 @@ func connectNBD(srv *torus.Server, f *block.BlockFile, target string, closer cha
 		fmt.Fprintf(os.Stderr, "error from nbd server: %s\n", err)
 		os.Exit(1)
 	}
-	return handle.Close()
+	return nil
 }
 
 type finder struct {

internal/nbd/nbd.go

@@ -218,51 +218,55 @@ func (nbd *NBD) Serve() error {
 		}(nbd)
 	}
 
-	waitDisconnect(nbd.nbd)
+	// NBD_DO_IT does not return until disconnect
+	if err := ioctl(nbd.nbd.Fd(), ioctlDoIt, 0); err != nil {
+		clog.Errorf("error %s: ioctl returned %v", nbd.nbd.Name(), err)
+	}
 
 	wg.Wait()
 	return nil
 }
 
-func (nbd *NBD) Close() error {
-	// FIXME: Now I understand what these did, and it terrifies me.
-	// syscall.Write(nbd.setsocket, make([]byte, 28))
-	// syscall.Close(nbd.setsocket)
-	nbd.Disconnect()
-	syscall.Close(nbd.socket)
-	return nbd.nbd.Close()
+func Detach(dev string) error {
+	f, err := os.Open(dev)
+	if err != nil {
+		return err
+	}
+	n := &NBD{nbd: f}
+	n.Disconnect()
+	return nil
 }
 
-func (nbd *NBD) Disconnect() error {
+func (nbd *NBD) Disconnect() {
+	var err error
 	if nbd.nbd == nil {
-		return nil
+		return
 	}
-	if err := ioctl(nbd.nbd.Fd(), ioctlDisconnect, 0); err != nil {
-		return &os.PathError{
-			Path: nbd.nbd.Name(),
-			Op:   "ioctl NBD_DISCONNECT",
-			Err:  err,
-		}
-	}
-	return nil
-}
 
-func waitDisconnect(f *os.File) {
+	clog.Infof("Running disconnection to %s", nbd.nbd.Name())
+
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	// NBD_DO_IT does not return until disconnect
-	if err := ioctl(f.Fd(), ioctlDoIt, 0); err != nil {
-		clog.Errorf("error %s: ioctl returned %v", f.Name(), err)
+	err = ioctl(nbd.nbd.Fd(), ioctlDisconnect, 0)
+	if err != nil {
+		clog.Errorf("error disconnecting %s. ioctl returned: %v", nbd.nbd.Name(), err)
 	}
-
-	clog.Debugf("Running disconnection to %s", f.Name())
-
-	if err := ioctl(f.Fd(), ioctlClearQueue, 0); err != nil {
-		clog.Errorf("error clear queue for %s. ioctl returned: %v", f.Name(), err)
+	err = ioctl(nbd.nbd.Fd(), ioctlClearSock, 0)
+	if err != nil {
+		clog.Errorf("error clear socket for %s. ioctl returned: %v", nbd.nbd.Name(), err)
+	}
+	err = ioctl(nbd.nbd.Fd(), ioctlClearQueue, 0)
+	if err != nil {
+		clog.Errorf("error clear queue for %s. ioctl returned: %v", nbd.nbd.Name(), err)
 	}
-	if err := ioctl(f.Fd(), ioctlClearSock, 0); err != nil {
-		clog.Errorf("error clear socket for %s. ioctl returned: %v", f.Name(), err)
+	err = ioctl(nbd.nbd.Fd(), ioctlClearQueue, 0)
+	if err != nil {
+		clog.Errorf("error clear queue for %s. ioctl returned: %v", nbd.nbd.Name(), err)
+	}
+	err = nbd.nbd.Close()
+	if err != nil {
+		clog.Errorf("error close nbd device %s. ioctl returned: %v", nbd.nbd.Name(), err)
 	}
 }