Re: Quota on tmpfs

[David Laight <david%l8s.co.uk@localhost>]

On Tue, Jul 17, 2012 at 01:51:17PM +0200, Francois Tigeot wrote:
> 
> Having a quota system based on visible file sizes gives at least consistent
> results with what a regular user sees when listing files or using du(1).

Ignoring fs metadata is unlikely to be a problem, it is only really
significant for sparse files (and maybe very small ones).

But you do need to use the 'sparse' size for sparse files.
Many moons ago someone change unixware so that 'ls -s' reported a
value based on the file size - not the number of block used.
Really wasn't a good change at all.
NFI if it got reverted.

A fixed value per file + the space allocated by data sectors seems
an acceptable number.
If the fs is going to share duplicate blocks I'm not sure what makes sense.
Maybe count per user? - but that is probably too hard!

        David

-- 
David Laight: david%l8s.co.uk@localhost