STABLE14-dirbuffer-fid-is-index-20050119

STABLE14-dirbuffer-fid-is-index-20050119

"The new buffer code (which I wrote) did not deal
with dcache object re-use, as I had conflated the concepts of "dcache *
reuse" and "dcache slot reuse".

This patch should fix this problem. It now stores the dcache index (aka slot number,
which is the same as the numeric part of the cache file's filename) in the
buffer instead of the ephemeral struct dcache pointer."

(cherry picked from commit 8ccd2d91d89fc3ed0170a458853ec95ff274c87d)