Why my NFS not work

You have to make sure you have allowed access to your nfs directory on the host machine by specifying it in /etc/exports.

Normally you export a different directory other than /mnt/nfs.

If you want to export /home/user from your host machine and your nios2 IP address is "w.x.y.z", then try the following in etc exports.

/home/user w.x.y.z(rw,no_root_squash)

You then might have to restart the nfs server on your host machine.

On the nios2, try using the following line in your /etc/rc script, or manually type it in after logging in.

/bin/mount -t nfs 192.168.0.7:/home/user /mnt/nfs -n -o nolock &

Hopefully this helps.