backing file per attribute type indexed by inode number to hold the extended
attributes.
This is working pretty well on my test systems, except for the "autostart"
feature. I need someone with a better handle on the VFS locking protocol
to go over that.
This is a work-in-progress. There are parts of this that could be re-factored
allowing this approach to be used on other types of file systems.
Adapted from FreeBSD.
thorpej