Re: name cache TTL?

[David Holland <dholland-tech%netbsd.org@localhost>]

On Sun, Nov 04, 2012 at 06:54:57AM +0100, Emmanuel Dreyfus wrote:
 > But that cannot handle negative caching. FUSE allows the filesystem to
 > specify a TTL for a ENOENT. I cannot implement it at the PUFFS level
 > like I did before, since there is no struct puffs_node associated with
 > an unexistant node. 

Anything that calls itself a name cache ought to support negative
caching. Someone(TM) needs to figure out a way to make it work.

 > The simpliest way of dealing with this would be to push down the name
 > cache TTL from struct puffs_node to puffs_namecache, and add an optional
 > struct timespec argument to cache_enter(). That argument would tell the
 > name cache how long the cache entry shall be valid at most. NULL would
 > mean current behavior.

Is this a puffs-specific cache_enter or the "real" one? Adding TTL
support to the kernel name cache would simplify the NFS code.

-- 
David A. Holland
dholland%netbsd.org@localhost