Umount Mobile Hard drive encounters device is busy problem

#umount/mnt/fourt
Umount:/mnt/fourt:device is busy.
(In some cases useful info about processes
The device is found by lsof (8) or fuser (1))


Fuser Overview
The Fuser command is used to display all process information that is using the specified file, file system, or sockets.
Cases:
#fuser-M-u/mnt/fourt
/mnt/fourt:14917c (Root) 14918c (root)
In the example, the-M and-u options are used to find all the PID of all processes that are using/mnt/fourt, and the owner of the process, such as 14917c (Root), where 14917 is the process Pid,root is the owner of the process.
Fuser displays the PID of the process that is using the specified File,file system or sockets. In the default display mode, each filename is followed by a character that indicates the current access type.
As shown below:
C
Current directory.
E
Executable being run.
F
Open file.
F
Open file for writing.
R
root directory.
M
Mmap ' ed file or shared library


To view the files used by the process:
# ls-al/proc/14917/fd/
Total 0
Dr-x------2 root root 0 Jul 28 09:58.
Dr-xr-xr-x 7 Root Screen 0 Jul 8 12:44..
Lr-x------1 root root 09:58 0-/dev/null
L-WX------1 root root 09:58 1-/dev/null
L-WX------1 root root 09:58 2-/dev/null
Lr-x------1 root root 09:58 3-/var/run/screen/s-aimin/14917.pts-6.centos64
lrwx------1 root root 09:58 5-/dev/ptmx
Lr-x------1 root root 09:58 6-/var/run/utmp

# ls-al/proc/14918/fd/
Total 0
Dr-x------2 root root 0 Jul 28 09:58.


#ps--ppid 14917
#ps--ppid 14918

Kill Process:
#kill-9 14917
#kill-9 14918

Again Umount

#umount/mnt/fourt