Re: Quota on tmpfs

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Fri, Jul 13, 2012 at 08:24:49AM +0200, Francois Tigeot wrote:
> On Thu, Jul 12, 2012 at 07:20:37PM +0000, David Holland wrote:
> 
> > It is possible that some of the enforcement logic could be made
> > fs-independent, but it's probably difficult without knowing how the
> > filesystem allocates resources. E.g. if you write() to fill in holes
> > in a file, outside the filesystem it's very difficult to know that
> > you're increasing your block usage, or for that matter by how much
> > when indirect blocks are (might be) involved.
> 
> This is not really an issue for me; I don't care about low-level storage
> and only manage visible file sizes.

This seems like a severe design bug, then.

Sparse files are a basic building block of many Unix applications,
particularly ones using databases.  Counting them as if they used
as much space on disk as they have bytes of readable length will
either just plain break stuff (due to spurious quota violations)
or render your new quota system unuseful to a large number of users.

Is there really a consensus among the Dragonfly developers that
a new quota system without sparse file support is a good thing?

Thor