mount: read data that is just written

able read on data not flushed
multiple file open shares the same file handle

fix https://github.com/chrislusf/seaweedfs/issues/1182 on linux

weed/filesys/dir.go

@@ -146,9 +146,8 @@ func (dir *Dir) Create(ctx context.Context, req *fuse.CreateRequest,
 	}
 
 	file := node.(*File)
-	file.isOpen = true
+	file.isOpen++
 	fh := dir.wfs.AcquireHandle(file, req.Uid, req.Gid)
-	fh.dirtyMetadata = true
 	return file, fh, nil
 
 }