Ian,

We've been hearing some reports of autofs removing entire home directories 
when mounts expire.  It appears that this could be some sort of race condition 
in the walk_tree code, where when the function starts the directory is 
unmounted and then autofs unlinks files in the the directory that is supposed 
to be umounted.  I've attached a patch to the rm_unwanted_fn which adds some 
additional checks before we unlink anything, and it prevents autofs from 
unlinking files (since I'm pretty sure that autofs never creates a regular 
file).  Let me know what you think.

Thanks,
Chris