[Samba] feature request: winbind use cached credentials more agressively

[Árpád Magosányi]

Hi!

Winbind is rather suboptimally reacts to networking changes.
I use my notebook in at least 3 different network settings, in one of them I
have very probabilistic access to DCs
(cisco vpn client is a crap).
An nss lookup sometimes takes very looong, sometimes even returns failure.
Sometimes I have to login as root and restart winbind to get to my X session
past the screensaver. This is far from production quality.

I guess the end-user feeling could be heightened by using cached credentials
more agressively. As wast majority of nss lookups are for data already
obtained, it might be wise to serve it from cache, and refresh it
asynchronously.