Here's how to work around this problem. If /home and /usr are on the same underlying local filesystem, you can't export them both. So just export /. NFS clients will then be able to mount /home and /usr via NFS just fine, but your NFS server's /etc/exports file will now be "legal," containing only one export line per underlying local filesystem. Now that you understand this implementation of Linux NFS, we're ready to take a look at the format of /etc/exports.