How to unmount a filesystem when when the device is busy?

This is tested on Linux. For Solaris also, use "fuser -c MOUNT-POINT".

# umount  /SERVER-A/rman
umount: /SERVER-A/rman: device is busy
umount: /SERVER-A/rman: device is busy

# fuser -m /SERVER-A/rman
/SERVER-A/rman:         31477c

# ps -eaf | grep 31477
oracle  31477 31448  0 09:52 pts/0    00:00:00 /bin/ksh

# df -h /SERVER-A/rman
Filesystem            Size  Used Avail Use% Mounted on
SERVER-A:/miszpool/mis
                      2.5T  1.9T  560G  78% /SERVER-A/rman

# ps -eaf | grep 31477
oracle  31477 31448  0 09:52 pts/0    00:00:00 /bin/ksh

# ps -eaf | grep 31448
dbauser1 31448 31447  0 09:51 pts/0    00:00:00 -ksh
oracle  31477 31448  0 09:52 pts/0    00:00:00 /bin/ksh

# kill -9 31477
# ps -eaf | grep 31448
dbauser1 31448 31447  0 09:51 pts/0    00:00:00 -ksh

# umount -f /SERVER-A/rman

# mount /SERVER-A/rman

# df -h /SERVER-A/rman
Filesystem            Size  Used Avail Use% Mounted on
SERVER-A:/miszpool/mis
                      2.5T  1.9T  560G  78% /SERVER-A/rman