juicefs sync fail：file name too long

[liujiangang01]

What happened:将cephfs的两个volume挂载到本地一个是/mnt/src/，一个是/mnt/dst/，用juicefs sync同步文件夹报错，但是用cp 命令手动拷贝报错的文件，是可以手动拷贝的

What you expected to happen:
希望cp能够支持的，juicefs sync也能支持

Environment:

• JuiceFS version (use juicefs --version) or Hadoop Java SDK version: v1.0.4
• Cloud provider or hardware configuration running JuiceFS: 物理机
• OS (e.g cat /etc/os-release): ubuntu20

[zhijian-pro]

The file name limit of 255 is the usual behavior

[davies]

Because the adding the random suffix to the filename, should be fixed.