Re: SUJ Changes

On Wed, May 26, 2010 at 2:59 PM, Mario Lobo <lobo_at_bsd.com.br> wrote:
> On Wednesday 26 May 2010 23:56:24 Garrett Cooper wrote:
>> On Wed, May 26, 2010 at 3:52 PM, Marcelo/Porks <marcelorossi_at_gmail.com>
> wrote:
>> > On 5/25/10, Marcelo/Porks <marcelorossi_at_gmail.com> wrote:
>> >> Hi! I tested the r208241 and it's seems to be ok but this calls my
>> >> atention to other thing: Could I disable de SU when the SUJ is
>> >> enabled?
>> >>
>> >> I did some tests and seems that I can do this (logs bellow).
>> >>
>> >> But will SUJ work properly with SU disabled?
>> >
>> > 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 it makes sense to have this as a force option as someone
>> may want to retain their journal instead of disposing of it
>> automatically.
>>
>> I think that the 2nd warnx should be the first warnx, and the 2nd
>> warnx can be removed as it'll be quickly followed up by <blah>
>> cleared. Changing `remove' to `removing' and changing `.sujournal' to
>> journal would a) make the action more correct and b) make the concept
>> more straightforward as to what's being removed, as Jeff or someone
>> else may decide to remove or rename .sujournal in the future, and it's
>> just another thing that users don't have to understand that aren't
>> familiar with FreeBSD or SUJ.
>>
> Is this available in 8-STABLE?

    Nope.

> Can it be?

    Not sure (fs_at_ folks should make the call), but definitely not before 8.1.

> Can this be activated on my current installation without loosing data?

    I suggest looking for SUJ in the current archives in the past 2
months. There are a number of threads that discuss how SUJ should be
enabled.
HTH,
-Garrett