Apparently some applications are confused by tmpfs's practice of
returning zero for the size of diretories.  In 2.4.20-pre6 Peter Anvin
submitted a change to make tmpfs directories always have a size of "1".

In the same spirit, this patch arranges for tmpfs directories to show
up as having 20 * number_of_entries, including "." and "..".

Apparently counting up the size of all the entries isn't worth the
hassle.