PUFFS_VN_LOOKUP2

[manu%netbsd.org@localhost (Emmanuel Dreyfus)]

Hi

FUSE LOOKUP, GETATTR and SETATTR have TTL for name and attributes. It
would greatly enhance perfuse performance if the kernel could keep track
of those, and avoid issuing tons of LOOKUPs and GETATTRs when it has
valid data.

Additionnaly, FUSE LOOKUP returns the node attributes. If we handled
that, it could save an extra GETATTR

I therefore propose the addition of two PUFFS operations:
- PUFFS_VN_LOOKUP2 in which the reply would feature entry  TTL and
attributes TTL and values.
- PUFFS_VN_GETATTR2 in which the reply would feature attributes TTL.

Next, PUFFS kernel code should be modified so that
cache_enter/cache_lookup could be used with the TTL. 

I am not sure about what could be done with FUSE SETATTR attribute TTL.
Should libperfuse set it to a hardcoded value? But what value?

-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
manu%netbsd.org@localhost