Problems with unmounting a network share in linux

[januttall]

I have written a short script to back up a proxy server running ubuntu 10.10 using smbfs share and rsync but when the rsync is complet it fails to unmount the directory i have also tryed forcing the umount and this also fails.
umount -fv /mount_location
umount: Device or resource busy

[script]
mount -t smbfs -o username=*,password=* //Remote_Mount /Local_Mount_Point

/Local_Mount_Point/rsync (this runs the actual rsync comand as i was having errors on rsync if the mount failed and with this option it cant run if the mount fails)

[rsync script]
rsync -auv --exclude /remotemnt --exclude /squidcache /* /Local_Mount_Point

cd /var

umount -fv /Local_Mount_Point

any ideas ?

[pete]

It sounds like something is hanging open

What does lsof tell you? specifically

lsof | grep rsync

[januttall]

thanks for the reply I have run
lsof | grep rsync
and nothing is displayed however when the below is run
lsof | grep /Local_Mount_Point
shows the local user that mounted the drive is in the folder even when the script tells it to go back to the home directory after running rsync

[pete]

Sorry, I should have read your initial post more clearly. You're trying to unmount /Local_Mount_Point using the rsync script sitting inside it - that'll never work.

You can't unmount something that's being accessed. You especially can't if the thing you're trying to umount it with is the thing sitting inside it. Even though you change directory to /var within the script, the script is still running from /Local_Mount_Point.

Run your script from the user's homedir and pick another way of checking for a failed mount, say checking /proc/mounts for your particular share.

  if ! grep -q /Remote_Mount /proc/mounts ; then
    if ! mount /Remote_Mount ; then
      echo "failed"
      exit 1
    fi
  fi
  echo "succeeded."
  # do rsync stuff here

(Example nicked from ServerFault)

[januttall]

Thanks for the help. I have run several tests and it seems to have worked as the mount is disconnected and the backup did complete.