Re: Quota on tmpfs

[Francois Tigeot <ftigeot%wolfpond.org@localhost>]

On Fri, Jul 13, 2012 at 08:25:54AM +0000, David Holland wrote:
> On Fri, Jul 13, 2012 at 10:15:55AM +0200, Francois Tigeot wrote:
>  > The quickest way is to save usage counters and limits in a regular file 
> like
>  > the old BSD quota system used to do it.
>  > This can even be done in userland.
> 
> Limits, yes; saving the usage data in userland is problematic, because
> it's likely to end up inconsistent with the filesystem.
> 
> Although I suppose if you're willing to run quotacheck on every boot,
> this doesn't matter much. (tip though: quotacheck is inherently slow)

This isn't worse than the old quota code so far.

There are hooks to implement filesystem-specific synchronization routines
which could be much better in that regard.
I like the idea of the hidden inode + journal integration, it seems to be
optimal.

> Are you likely to adopt the new NetBSD quota(3) library interface? It
> may be a little more complicated, but it will let you import the
> traditional quota tools from NetBSD instead of rewriting them and save
> you from having to port a few pieces of 3rd-party software... and it
> shouldn't constrain your implementation much.

I'm looking into it; the NetBSD implementation seems to be sufficiently
different I'm not sure it could be used as-is.

-- 
Francois Tigeot