mount: release resources when Forget() is called

address https://github.com/chrislusf/seaweedfs/issues/1929

weed/filesys/file.go

@@ -151,7 +151,7 @@ func (file *File) Setattr(ctx context.Context, req *fuse.SetattrRequest, resp *f
 			}
 			entry.Chunks = chunks
 			file.entryViewCache, _ = filer.NonOverlappingVisibleIntervals(file.wfs.LookupFn(), chunks)
-			file.reader = nil
+			file.setReader(nil)
 		}
 		entry.Attributes.FileSize = req.Size
 		file.dirtyMetadata = true
@@ -261,6 +261,8 @@ func (file *File) Forget() {
 	t := util.NewFullPath(file.dir.FullPath(), file.Name)
 	glog.V(4).Infof("Forget file %s", t)
 	file.wfs.fsNodeCache.DeleteFsNode(t)
+	file.wfs.ReleaseHandle(t, 0)
+	file.setReader(nil)
 }
 
 func (file *File) maybeLoadEntry(ctx context.Context) (entry *filer_pb.Entry, err error) {
@@ -280,9 +282,6 @@ func (file *File) maybeLoadEntry(ctx context.Context) (entry *filer_pb.Entry, er
 		return entry, err
 	}
 	if entry != nil {
-		if entry.Attributes == nil {
-			entry.Attributes = &filer_pb.FuseAttributes{}
-		}
 		file.setEntry(entry)
 	} else {
 		glog.Warningf("maybeLoadEntry not found entry %s/%s: %v", file.dir.FullPath(), file.Name, err)
@@ -330,19 +329,29 @@ func (file *File) addChunks(chunks []*filer_pb.FileChunk) {
 		file.entryViewCache = filer.MergeIntoVisibles(file.entryViewCache, chunk)
 	}
 
-	file.reader = nil
+	file.setReader(nil)
 
 	glog.V(4).Infof("%s existing %d chunks adds %d more", file.fullpath(), len(entry.Chunks), len(chunks))
 
 	entry.Chunks = append(entry.Chunks, newChunks...)
 }
 
+func (file *File) setReader(reader io.ReaderAt) {
+	r := file.reader
+	if r != nil {
+		if closer, ok := r.(io.Closer); ok {
+			closer.Close()
+		}
+	}
+	file.reader = reader
+}
+
 func (file *File) setEntry(entry *filer_pb.Entry) {
 	file.entryLock.Lock()
 	defer file.entryLock.Unlock()
 	file.entry = entry
 	file.entryViewCache, _ = filer.NonOverlappingVisibleIntervals(file.wfs.LookupFn(), entry.Chunks)
-	file.reader = nil
+	file.setReader(nil)
 }
 
 func (file *File) clearEntry() {
@@ -350,7 +359,7 @@ func (file *File) clearEntry() {
 	defer file.entryLock.Unlock()
 	file.entry = nil
 	file.entryViewCache = nil
-	file.reader = nil
+	file.setReader(nil)
 }
 
 func (file *File) saveEntry(entry *filer_pb.Entry) error {

weed/filesys/filehandle.go

@@ -130,7 +130,7 @@ func (fh *FileHandle) readFromChunks(buff []byte, offset int64) (int64, error) {
 		if chunkResolveErr != nil {
 			return 0, fmt.Errorf("fail to resolve chunk manifest: %v", chunkResolveErr)
 		}
-		fh.f.reader = nil
+		fh.f.setReader(nil)
 	}
 
 	reader := fh.f.reader
@@ -138,7 +138,7 @@ func (fh *FileHandle) readFromChunks(buff []byte, offset int64) (int64, error) {
 		chunkViews := filer.ViewFromVisibleIntervals(fh.f.entryViewCache, 0, math.MaxInt64)
 		reader = filer.NewChunkReaderAtFromClient(fh.f.wfs.LookupFn(), chunkViews, fh.f.wfs.chunkCache, fileSize)
 	}
-	fh.f.reader = reader
+	fh.f.setReader(reader)
 
 	totalRead, err := reader.ReadAt(buff, offset)
 
@@ -207,12 +207,7 @@ func (fh *FileHandle) Release(ctx context.Context, req *fuse.ReleaseRequest) err
 		fh.f.isOpen--
 
 		fh.f.wfs.ReleaseHandle(fh.f.fullpath(), fuse.HandleID(fh.handle))
-		if closer, ok := fh.f.reader.(io.Closer); ok {
-			if closer != nil {
-				closer.Close()
-			}
-		}
-		fh.f.reader = nil
+		fh.f.setReader(nil)
 	}
 
 	return nil