On Thu 25-03-10 23:38:24, tytso@xxxxxxx wrote: > On Fri, Mar 26, 2010 at 01:47:38AM +0100, Jan Kara wrote: > > This is definitely a move in the right direction. I'd be even happier > > if e2fsck would write quota file directly - then we could just make > > quota files hidden inodes, start doing quota accounting immediately > > on mount and always do quota journaling. That would save us quite some > > trouble in kernel. The only problem with this is that we'd need to pull > > knowledge about quota formats in e2fsck... > > Yes, quite possibly. How quota is currently is set up is quite > kludgy, with magic options that do nothing but display magic options > in /proc/mounts, just in case that's a hard link to /etc/mtab. It > also looks like that some of the magic is in various distribution's > init.d scripts, and so while I very much want to clean things up, it > wasn't clear to me how much flexibility we would have without worrying > about breaking the init scripts for Debian, Ubuntu, RHEL, SLES, > Fedora, Open SuSE, etc. Well, init scripts can be fixed and if we provide some grace time for distros to catch up I believe this isn't that hard. > There may also be other programs that depend on the existence of > aquota.user, and may be reading and writing them in various random > ways, and there is the question of how do we provide compatibility > with these other programs, some of which may not be within quotatools, > but in various magic virtualization or container or cluster management > systems.... Yeah, this is possible, although I'm not aware of any such program - except for repquota and warnquota from quota-tools but I'll take care about those. What some programs do is that they change quota files via kernel (quotactl) or call programs from quota-tools but that is fine (and ultimately the only way I'd like to leave to userspace when the filesystem is mounted). > So maintaining compatibility between older kernels, newer kernels, > older init scripts, new init scripts, etc. may make changing the quota > system quite difficult. I would like to do as much cleanup as we can, > though. Actually, XFS and OCFS2 already use hidden quota files. So it won't be completely new thing. > One question I have --- do we really have to support the 2 or 3 > different quota variants? How many people/distributions are still > using the original old quota system? One thing that worries me is > that it looks like the old (non-journaled) quota system may be the > primary system still being used by Canonical and Debian... I really > do hope I'm wrong, but there are a bunch of HOWTO's that still people > to use usrquota and grpquota in /etc/fstab, and not the newer > usrjquota and grpjquota mount options. Yeah, I believe that support for the oldest quota format can be phased out - the new format is around for something like 10 years and it had it's problems at that time already. I guess I'll add a warning to the next release of quota-tools to the people still using it. About quota journaling - it has some performance penalty (changed quota structures have to be written on every transaction commit instead of just once on quotaoff time / sync) but I belive that if someone is running journaled filesystem, he also should use journaled quotas because it's essentially filesystem metadata. Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
