Re: SUJ Changes

On Thursday 27 May 2010 10:13:38 am Marcelo/Porks wrote:
> On Thu, May 27, 2010 at 10:33 AM, John Baldwin <jhb_at_freebsd.org> wrote:
> > On Wednesday 26 May 2010 7:56:24 pm Garrett Cooper wrote:
> >> On Wed, May 26, 2010 at 3:52 PM, Marcelo/Porks <marcelorossi_at_gmail.com> 
wrote:
> >> >
> >> > Hi guys. I'm not sure if I could call this a problem but I can disable
> >> > SU when SUJ is enabled, so SUJ will remain enabled and SU will be
> >> > disabled.
> >> >
> >> > #tunefs -j enable /dev/device
> >> > #tunefs -n disable /dev/device
> >> >
> >> > I did a patch for sbin/tunefs/tunefs.c that disable SUJ when the user
> >> > disable SU. Maybe this will be useful for some of you.
> >> >
> >> > Thanks.
> >> >
> >> >
> >> > Index: sbin/tunefs/tunefs.c
> >> > ===================================================================
> >> > --- sbin/tunefs/tunefs.c        (revision 208580)
> >> > +++ sbin/tunefs/tunefs.c        (working copy)
> >> > _at__at_ -460,6 +460,14 _at__at_
> >> >                        if ((~sblock.fs_flags & FS_DOSOFTDEP) ==
> > FS_DOSOFTDEP)
> >> >                                warnx("%s remains unchanged as 
disabled",
> > name);
> >> >                        else {
> >> > +                               /* also disable SUJ */
> >> > +                               if ((sblock.fs_flags & FS_SUJ) == 
FS_SUJ)
> > {
> >> > +                                       warnx("soft updates journaling
> >> > will be disabled too");
> >> > +                                       journal_clear();
> >> > +                                       sblock.fs_flags &= ~FS_SUJ;
> >> > +                                       sblock.fs_sujfree = 0;
> >> > +                                       warnx("remove .sujournal to
> >> > reclaim space");
> >> > +                               }
> >> >                                sblock.fs_flags &= ~FS_DOSOFTDEP;
> >> >                                warnx("%s cleared", name);
> >> >                        }
> >>
> > I think that attempting to disable SU if SUJ
> > is enabled should just fail with an error message.  The sysadmin can then
> > choose to disable both SUJ and SU if desired.
> 
> If SU is disabled and One tries to enable SUJ then SU will be
> automatically enabled.
> So Why not automatically disable SUJ when One tries to disable SU?

I'm probably not a big fan of either really. :)  For something as rarely done
as tunefs I would prefer to err on the side of caution and require the admin
to explicitly specify everything.

-- 
John Baldwin