Provide InitIn.SupportsVersion and InitIn.SupportsNotify.

fuse/server.go

@@ -441,6 +441,10 @@ func (ms *Server) write(req *request) Status {
 // InodeNotify invalidates the information associated with the inode
 // (ie. data cache, attributes, etc.)
 func (ms *Server) InodeNotify(node uint64, off int64, length int64) Status {
+	if !ms.kernelSettings.SupportsNotify(NOTIFY_INVAL_INODE) {
+		return ENOSYS
+	}
+
 	entry := &NotifyInvalInodeOut{
 		Ino:    node,
 		Off:    off,
@@ -512,6 +516,9 @@ func (ms *Server) DeleteNotify(parent uint64, child uint64, name string) Status
 // within a directory changes. You should not hold any FUSE filesystem
 // locks, as that can lead to deadlock.
 func (ms *Server) EntryNotify(parent uint64, name string) Status {
+	if !ms.kernelSettings.SupportsNotify(NOTIFY_INVAL_ENTRY) {
+		return ENOSYS
+	}
 	req := request{
 		inHeader: &InHeader{
 			Opcode: _OP_NOTIFY_ENTRY,
@@ -543,6 +550,26 @@ func (ms *Server) EntryNotify(parent uint64, name string) Status {
 	return result
 }
 
+// SupportsVersion returns true if the kernel supports the given
+// protocol version or newer.
+func (in *InitIn) SupportsVersion(maj, min uint32) bool {
+	return in.Major >= maj && in.Minor >= min
+}
+
+// SupportsNotify returns whether a certain notification type is
+// supported. Pass any of the NOTIFY_INVAL_* types as argument.
+func (in *InitIn) SupportsNotify(notifyType int) bool {
+	switch notifyType {
+	case NOTIFY_INVAL_ENTRY:
+		return in.SupportsVersion(7, 12)
+	case NOTIFY_INVAL_INODE:
+		return in.SupportsVersion(7, 12)
+	case NOTIFY_INVAL_DELETE:
+		return in.SupportsVersion(7, 18)
+	}
+	return false
+}
+
 var defaultBufferPool BufferPool
 
 func init() {

fuse/types.go

@@ -341,13 +341,14 @@ type NotifyInvalDeleteOut struct {
 }
 
 const (
-	NOTIFY_POLL         = -1
+	//	NOTIFY_POLL         = -1
 	NOTIFY_INVAL_INODE = -2
 	NOTIFY_INVAL_ENTRY = -3
-	NOTIFY_STORE        = -4
-	NOTIFY_RETRIEVE     = -5
+	//	NOTIFY_STORE        = -4
+	//	NOTIFY_RETRIEVE     = -5
 	NOTIFY_INVAL_DELETE = -6
-	NOTIFY_CODE_MAX     = -6
+
+//	NOTIFY_CODE_MAX     = -6
 )
 
 type FlushIn struct {