title: fusermount: umount failed: Invalid argument
body: <p>When I try to umount the FUSE file system, I get an error:</p>
  
  <pre><code>root@ubuntu:/home/fufs/src# fusermount -u /tmp/kpfss
  fusermount: failed to unmount /tmp/kpfss: Invalid argument
  root@ubuntu:/home/fufs/src# fusermount -z -u /tmp/kpfss
  fusermount: failed to unmount /tmp/kpfss: Invalid argument
  </code></pre>
  
  <p>How can I umount the file system? Thanks.</p>