NFS refuses to unmount
I have a drive on a server that is shared via nfs to a client. This works as expected. Then I want to unmount the drive from the server. I first unmount the drive from the client:
Then I comment out the drive in /etc/exports on the server and run:
sudo exportfs -a
Then I try to unmount it on the server, but it is busy. lsof and fuser shows nothing. I have even tried stopping nfsd and rpd. One process always remains that cant be killed, it is called nfsiod. If i restart the server the drive can be mounted and unmounted as usual, until a client mounts it. After this it is always locked, even if the client unmounts. What is going on?