The problem of use "FS.mount"

Please include the following in your bug report:

**Version of emscripten/emsdk:**
3.1.0

I used -lnodefs.js ;
module.FS.mkdir("/rootDir");
module.FS.mount( module.NODEFS, { root: "H:"} ,"/rootDir"} );
But The first file read is normal ，If read a file in the same directory again, the file cannot be found