Add nc_timeout to struct namecache?

[Emmanuel Dreyfus <manu%netbsd.org@localhost>]

Hi

In order to handle FUSE lookups TTL, I need to somehow keep track of
a node cache expiry date. I can do that in struct puffs_node, but that
mean I will lookup the cache, check expiry and decide to not use
cached entry if it is expired. In that case the entry remains in name cache,
and is even been refreshed because I looked it up. That does not seems
to be the right way.

The laternative is to add nc_tiemout in struct  namecache, and add a 
timeout argument to cache_enter. If zero, then previous name cache 
behavior is used. If non-zero, it specify when cache_prune must get
rid of the entry, by using nc_timeout instead of nc_hittime.

Opinions?

-- 
Emmanuel Dreyfus
manu%netbsd.org@localhost