The hash.h hash_long function, when used on a 64 bit machine, ignores many
of the middle-order bits. (The prime chosen it too bit-sparse).
IP addresses for clients of an NFS server are very likely to differ only in
the low-order bits. As addresses are stored in network-byte-order, these
bits become middle-order bits in a little-endian 64bit 'long', and so do
not contribute to the hash. Thus you can have the situation where all
clients appear on one hash chain.
So, until hash_long is fixed (or maybe forever), us a hash function that
works well on IP addresses - xor the bytes together.
Thanks to "Iozone" <capps@iozone.org> for identifying this problem.
Cc: "Iozone" <capps@iozone.org>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1f1e030bf7