Trying to forcefully unmount any device like NFS or CD-ROM and getting an error or 'mount point is busy' ?
Mount point is busy
Text file is busy
The only thing you need to do is find those processes which are trying to access that device and kill them.
# lsof | grep (mount point)
this will show you the process IDs which are accessing the mount point. Once you get the process IDs you can kill them manually.
# kill -9 (process ID)
This command is useful if a particular file is shown as busy rather than a directory.
# fuser -km (filename)
-k kill the process accessing the mentioned file
-m specifies the file on a mounted file system or a block device i.e. mounted
Once done you can unmount the device
# umount (mount point)
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