MountConfig: add FuseImpl field to select macOS FUSE implementation

mount_config.go

@@ -118,8 +118,8 @@ type MountConfig struct {
 	//
 	// Normally on OS X we mount with the novncache option
 	// (https://tinyurl.com/52hz9vya), which disables entry caching in the
-	// kernel. This is because osxfuse does not honor the entry expiration values
-	// we return to it, instead caching potentially forever
+	// kernel. This is because macFUSE (osxfuse) does not honor the entry
+	// expiration values we return to it, instead caching potentially forever
 	// (https://tinyurl.com/2rr6cd3m), and it is probably better to fail to cache
 	// than to cache for too long, since the latter is more likely to hide
 	// consistency bugs that are difficult to detect and diagnose.
@@ -167,9 +167,16 @@ type MountConfig struct {
 	// OS X only.
 	//
 	// The name of the mounted volume, as displayed in the Finder. If empty, a
-	// default name involving the string 'osxfuse' is used.
+	// default name involving the string 'osxfuse' (the old name of macFUSE)
+	// is used.
 	VolumeName string
 
+	// OS X only.
+	//
+	// The FUSE implementation to use. One of FUSEImplFuseT (default) or
+	// FUSEImplMacFUSE.
+	FuseImpl FUSEImpl
+
 	// Additional key=value options to pass unadulterated to the underlying mount
 	// command. See `man 8 mount`, the fuse documentation, etc. for
 	// system-specific information.
@@ -193,6 +200,13 @@ type MountConfig struct {
 	EnableParallelDirOps bool
 }
 
+type FUSEImpl uint8
+
+const (
+	FUSEImplFuseT = iota
+	FUSEImplMacFUSE
+)
+
 // Create a map containing all of the key=value mount options to be given to
 // the mount helper.
 func (c *MountConfig) toMap() (opts map[string]string) {

mount_darwin.go

@@ -381,10 +381,13 @@ func startFuseTServer(binary string, argv []string,
 }
 
 func mountFuset(
-	bin string,
 	dir string,
 	cfg *MountConfig,
 	ready chan<- error) (dev *os.File, err error) {
+	fuseTBin, err := fusetBinary()
+	if err != nil {
+		return nil, err
+	}
 
 	fusekernel.IsPlatformFuseT = true
 	env := []string{}
@@ -403,7 +406,7 @@ func mountFuset(
 	env = append(env, "_FUSE_COMMVERS=2")
 	argv = append(argv, dir)
 
-	return startFuseTServer(bin, argv, env, false, cfg.DebugLogger, ready)
+	return startFuseTServer(fuseTBin, argv, env, false, cfg.DebugLogger, ready)
 }
 
 func mount(
@@ -412,8 +415,13 @@ func mount(
 	ready chan<- error) (dev *os.File, err error) {
 
 	fusekernel.IsPlatformFuseT = false
-	if fuset_bin, err := fusetBinary(); err == nil {
-		return mountFuset(fuset_bin, dir, cfg, ready)
+	switch cfg.FuseImpl {
+	case FUSEImplMacFUSE:
+		dev, err = mountOsxFuse(dir, cfg, ready)
+	case FUSEImplFuseT:
+		fallthrough
+	default:
+		dev, err = mountFuset(dir, cfg, ready)
 	}
-	return mountOsxFuse(dir, cfg, ready)
+	return
 }

samples/mount_hello/mount.go

@@ -50,6 +50,7 @@ func main() {
 
 	cfg := &fuse.MountConfig{
 		ReadOnly: *fReadOnly,
+		FuseImpl: fuse.FUSEImplMacFUSE,
 	}
 
 	if *fDebug {