[Labeled-nfs] [RFC Labeled NFS] Labeling support for NFSv4

[David P. Quigley]

This is the first set of patches for the labeled-nfs work since early August.
Much has changed since then and we have a reasonably functional prototype of
the dumb server implementation. This patch series provides the ability to
retrieve and set labels on the server, provides callback notification for label
changes on the server, and life-cycle management for the fattr structure which
is used to transport the labels.

The patch series should apply on top of any 2.6.24-rc2 kernel and I know for a
fact that it will apply on top of commit 
9418d5dc9ba40b88737580457bf3b7c63c60ec43 in Linus's git tree. To get the tree
up and running for testing just apply the patch and have fun.