I wanted to put a linux ISO up on one of my servers so I can download the
ISO.  Then I wanted to grab the files off the disc if I ever needed an RPM
or two, so I did a 'mount redhat.iso ./ -o loop'.  Little did I realize
that this would make the ISO disappear.  The files are all there, I can
browse through the files on the ISO but the file itself is nowhere to be
found.  How do I unmount the ISO so I can move the mount point?  I try a
umount redhat.iso, of course that doesn't work because the ISO is
non-existant on the filesystem.  Is there any way to do this?

-Brian