Force unmount of CIFS

Q. I have a linux box with a windows mount point that lost connection to the server. I can't do anything with it - any time I do a "df" or "ls" command it hangs and takes forever to time out. What should I do, aside from rebooting and disabling that mount.

A. With NFS mount, you can always use "force unmount", with -f:

umount -f /mnt/nfsmount

With windows mount, you can use "lazy" unmount:

umount -l /mnt/cifsmount

From the man pages:

Lazy unmount. Detach the filesystem from the filesystem  hierarchy now, and cleanup all references to the filesystem as soon as it is not busy anymore. (Requires kernel 2.4.11 or later.)"