by Nathan Scott[permalink] [raw]
On Oct 26, 11:00am, Stephen C. Tweedie wrote:
> Subject: Re: Quota mods needed for journaled quota
> > This would allow ext3 to do that which it needs to do differently
> > at Q_QUOTAON and would also allow Jan's changes to work in such
> > a way that both the current form of dquot structure and his new
> > version of dquots could be used together
> Adding the init_quota hook would do that, as the filesystem will be
> able to install its own dq_ops methods during the init so we get the
> flexibility you are asking for anyway.
Hmmm ... I'm not so sure. In order to have the flexibility
of filesystem-specific dquot formats, the struct dquot would
need to become more like struct inode/super_block, i.e. not
hardcoding the ondisk structure into the incore structure
(using a union and a generic pointer, as inode/super_block do).
The DQUOT_SYNC mechanism would need to be able to be overridden
per-filesystem also. It isn't really as cut-and-dried as "per-
filesystem" either, because an ext2/3 filesystem might make use
of either the original dquot format or Jan's newer format, either
at mount time or even after doing a quota_off & quota_on with a
new quota file format (that would be quite clean).
But I've sidetracked completely from what you were originally
talking about now, which had nothing to do with a different
ondisk format at all.