How to umount when 'device is busy'

For Linux, if can not umount due to 'device is busy', do one of the following, this example shows Spycer was doing something.

1)

# umount /media/spycer-vol0/
umount: /media/spycer-vol0: device is busy
umount: /media/spycer-vol0: device is busy
# fuser -km /media/spycer-vol0/
/media/spycer-vol0/: 25575c
# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sdb1              57G   30G   25G  55% /
tmpfs                 5.9G   33M  5.9G   1% /dev/shm
#

or

2)

# umount /media/spycer-vol0/
umount: /media/spycer-vol0: device is busy
umount: /media/spycer-vol0: device is busy

# fuser -m /media/spycer-vol0/
/media/spycer-vol0/: 22202

# ps auxw | grep 22202
root     22202 36.5  2.0 853284 248292 ?       Sl   10:20   5:04 /opt/DVS/Spycer/bin/SpycerAgent
root     23668  0.0  0.0  61180   764 pts/1    S+   10:34   0:00 grep 22202

# service spyceragent stop
Stopping SpycerAgent ...
SpycerAgent is stopped.
# umount /media/spycer-vol0/
# 

 3)

# lsof /media/spycer-vol0
# kill [process #]

See this web page also:
http://ocaoimh.ie/2008/02/13/how-to-umount-when-the-device-is-busy/