umount: /home: device is busy

umount /home
umount: /home: device is busy
umount: /home: device is busy

[root@ns28suang ~]# cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / ext3 rw,data=ordered 0 0
/dev /dev tmpfs rw 0 0
/proc /proc proc rw 0 0
/sys /sys sysfs rw 0 0
none /selinux selinuxfs rw 0 0
/proc/bus/usb /proc/bus/usb usbfs rw 0 0
devpts /dev/pts devpts rw 0 0
/dev/sda3 /home ext3 ro,data=ordered 0 0
tmpfs /dev/shm tmpfs rw 0 0
none /proc/sys/fs/binfmt_misc binfmt_misc rw 0 0
/etc/auto.misc /misc autofs rw,fd=6,pgrp=2129,timeout=300,minproto=5,maxproto=5,indirect 0 0
-hosts /net autofs rw,fd=11,pgrp=2129,timeout=300,minproto=5,maxproto=5,indirect 0 0
[root@ns28suang ~]# umount /dev/sda3
umount: /home: device is busy
umount: /home: device is busy
[root@ns28suang ~]# fuser -m /dev/sda3
/dev/sda3:           29601c
[root@ns28suang ~]# ps -auxw | grep 2960
Warning: bad syntax, perhaps a bogus '-'? See /usr/share/doc/procps-3.2.7/FAQ
root      7121  0.0  0.0   3916   680 pts/1    S+   23:19   0:00 grep 2960
root     29601  0.0  0.0   5076   516 ?        Ss   Jan24   0:00 /usr/sbin/vsftpd /etc/vsftpd/vsftpd.conf
[root@ns28suang ~]# /etc/rc.d/init.d/vsftpd stop
Shutting down vsftpd: [  OK  ]
[root@ns28suang ~]# umount /dev/sda3
[root@ns28suang ~]#
[root@ns28suang ~]#
[root@ns28suang ~]# mount -a
[root@ns28suang ~]# cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / ext3 rw,data=ordered 0 0
/dev /dev tmpfs rw 0 0
/proc /proc proc rw 0 0
/sys /sys sysfs rw 0 0
none /selinux selinuxfs rw 0 0
/proc/bus/usb /proc/bus/usb usbfs rw 0 0
devpts /dev/pts devpts rw 0 0
tmpfs /dev/shm tmpfs rw 0 0
none /proc/sys/fs/binfmt_misc binfmt_misc rw 0 0
/etc/auto.misc /misc autofs rw,fd=6,pgrp=2129,timeout=300,minproto=5,maxproto=5,indirect 0 0
-hosts /net autofs rw,fd=11,pgrp=2129,timeout=300,minproto=5,maxproto=5,indirect 0 0
/dev/sda3 /home ext3 rw,data=ordered 0 0
[root@ns28suang ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1             9.5G  2.1G  6.9G  24% /
tmpfs                 1.7G     0  1.7G   0% /dev/shm
/dev/sda3              48G   39G  6.8G  85% /home