<p>I have an NFS-mounted directory on a Linux machine that has hung. I've tried to force an unmount, but it doesn't seem to work:</p>

<pre><code>$ umount -f /mnt/data
$ umount2: Device or resource busy
$ umount: /mnt/data: device is busy
</code></pre>

<p>If I type "<code>mount</code>", it appears that the directory is no longer mounted, but it hangs if I do "<code>ls /mnt/data</code>", and if I try to remove the mountpoint, I get:</p>

<pre><code>$ rmdir /mnt/data
rmdir: /mnt/data: Device or resource busy
</code></pre>

<p>Is there anything I can do other than reboot the machine?</p>

You might try a lazy unmount:
```
```
umount -l
```
```