Zoot wrote:
>> This is normal and expected behavior.  One problem may be that your 
>> server is slow, and thus there are RPCs left outstanding for a bit on 
>> your client after your application exits.  The COMMIT calls from that 
>> trace suggest that there is dirty data the client is writing back to the 
>> server.
> But I had expected that umount blocks until the commit calls are
 > finished as it is with local file systems?

Sorry, it doesn't.  It has no way of knowing how long those RPCs will take.

There is a "lazy unmount" facility that removes the NFS share from your 
client's name space and handles the outstanding RPCs in the background. 
  I'm not sure if it's working, but you could try "umount -l".