inode clashes (linux 2.2.x, arla 0.2x)

[Lyle Seaman]

The mapping in "stock" AFS uses the volume and vnode numbers, so this should
happen most often when dealing with two "cellular" mount points.  It can
also happen with two mount points whose mounted volume IDs are the same in
the lower 16 bits.

The best solution is probably to use a better mixing function to generate
inode numbers.  vnode and volume numbers really aren't very random, and the
simple function that AFS uses doesn't adequately compensate for their
predictability.