unmounting an exported filesystem

[Steve Feehan <steve cis ksu edu>]

I ocassionaly mount cdroms and export them through nfs. The problem is
that I can't unmount the cd without stopping and restarting nfs.

I first remove the reference to /mnt/cdrom from /etc/exports and then:

[root wamego /etc]# umount /mnt/cdrom  
umount: /mnt/cdrom: device is busy
[root wamego /etc]# rc.d/init.d/nfs stop
Shutting down NFS services:  [  OK  ]
Shutting down NFS mountd: [  OK  ]
Shutting down NFS daemon: [  OK  ]
Shutting down NFS quotas: [  OK  ]
[root wamego /etc]# rc.d/init.d/nfs start
Starting NFS services:  [  OK  ]
Starting NFS quotas: [  OK  ]
Starting NFS mountd: [  OK  ]
Starting NFS daemon: [  OK  ]
[root wamego /etc]# umount /mnt/cdrom
[root wamego /etc]#

Is there a way to unmount a shared cdrom without stopping nfs? I've
tried:

# /etc/rc.d/init.d/nfs restart 

after removing the reference to /mnt/cdrom from /etc/exports but it does
not work.

And what impact does stopping and restarting nfs have on other users who
are accessing files on other filesystems that are exported? Thanks.

--
Steve Feehan