On Sep 12, 2005, at 5:04 PM, Gordon Waidhofer wrote:

>
> Interfaces like statvfs() can report results more precisely
> than file system globals. For example, f_bavail and f_favail can
> be derived to reflect quotas -- it says how much is actually
> available to the calling uid.

Oh dear, that turns into a rats nest rather quickly.  The trick is  
dealing with group quotas.  What if your uid has no quota, but your  
primary gid (or any of your secondary supplemental groups) has one?   
What are the correct semantics?  I think the most common usage model  
for quotas is to set a quota for a group (say "students") and ensure  
that the containing directories that those users will write files in  
always have the appropriate group ownership.

-- thorpej