busy buffer problem on HEAD

[Richard Nyberg <rnyberg@xxxxxxxxxxxxx>]

Booting, logging in as root and running "shutdown -r now" works.
Booting, logging in as a regular user and running "shutdown -r now" hits
the "busy buffer problem". This is probably because my regular users home
directories are on nfs. This didn't happen before the "BIO" commit so
taht's my suspect.

I've uploaded core dumps to my crash directory on leaf.

        -Richard