serve, mountlib: test VFS release on shutdown and mount failure

cmd/mountlib/rc_test.go

@@ -2,6 +2,7 @@ package mountlib_test
 
 import (
 	"context"
+	"errors"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -18,6 +19,8 @@ import (
 	"github.com/rclone/rclone/fs/rc"
 	"github.com/rclone/rclone/fstest"
 	"github.com/rclone/rclone/fstest/testy"
+	"github.com/rclone/rclone/vfs"
+	"github.com/rclone/rclone/vfs/vfscommon"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -197,3 +200,21 @@ func TestRc(t *testing.T) {
 		require.True(t, os.IsNotExist(err))
 	})
 }
+
+func TestMountFailureVFSRelease(t *testing.T) {
+	localDir := t.TempDir()
+	f, err := fs.NewFs(context.Background(), localDir)
+	require.NoError(t, err)
+
+	failingMountFn := func(VFS *vfs.VFS, mountpoint string, opt *mountlib.Options) (<-chan error, func() error, string, error) {
+		return nil, nil, "", errors.New("simulated mount error")
+	}
+
+	mnt := mountlib.NewMountPoint(failingMountFn, "/invalid/mountpoint", f, &mountlib.Opt, &vfscommon.Opt)
+	initialActive := vfs.ActiveCount()
+
+	_, err = mnt.Mount()
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "simulated mount error")
+	assert.Equal(t, initialActive, vfs.ActiveCount(), "VFS should be shut down when MountFn fails")
+}

cmd/serve/servetest/rc.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/rclone/rclone/fs/rc"
+	"github.com/rclone/rclone/vfs"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -52,6 +53,9 @@ func TestRc(t *testing.T, in rc.Params) {
 	name := in["type"].(string)
 	addr := GetEphemeralPort(t)
 
+	// Track active VFS count before starting server
+	initialActive := vfs.ActiveCount()
+
 	// Start the server
 	in["fs"] = dir
 	in["addr"] = addr
@@ -71,7 +75,10 @@ func TestRc(t *testing.T, in rc.Params) {
 	_, err = serveStop.Fn(ctx, rc.Params{"id": id})
 	require.NoError(t, err)
 
-	// Check we can make no longer make connections to the server
+	// Check the VFS was properly released
+	assert.Equal(t, initialActive, vfs.ActiveCount(), "VFS should have been shut down after server stop")
+
+	// Check we can no longer make connections to the server
 	err = checkTCP(addr)
 	assert.Error(t, err)
 }

vfs/vfs.go

@@ -357,6 +357,12 @@ func activeCacheEntries() (vfs *VFS, count int) {
 	return vfs, count
 }
 
+// ActiveCount returns the total number of VFS instances in the active cache.
+func ActiveCount() int {
+	_, count := activeCacheEntries()
+	return count
+}
+
 // Fs returns the Fs passed into the New call
 func (vfs *VFS) Fs() fs.Fs {
 	return vfs.f