Re: ext3/jbd oops in journal_start

[Chris Mason <chris.mason@oracle.com>]

On Mon, Nov 02, 2009 at 10:06:36PM -0800, Sage Weil wrote:
> On Sat, 31 Oct 2009, Dmitry Monakhov wrote:
> 
> > Sage Weil <sage@newdream.net> writes:
> > 
> > > Hi,
> > >
> > > I'm consistently seeing ext3 oops on a fresh ~60 GB fs on 2.6.32-rc3 (and 
> > > 2.6.31).  data=writeback or data=ordered.  It's not the hardware or 
> > > drive... I have 8 boxes (each with slightly different hardware) that crash 
> > > identically.
> > Strange, 2.6.31 with ext3 is quite popular configuration...
> > Can you please post exact test-case.
> > >
> > > The oops is at fs/jbd/transaction.c, journal_start():
> > >
> > > 		J_ASSERT(handle->h_transaction->t_journal == journal);
> > *handle = journal_current_handle()
> > 
> > IMHO it's looks like you have entered here with current->journal_info != NULL
> > 
> > , but journal_info contains unexpected data
> > This may happens in two cases:
> > 1) calling jbd code from other filesystem.
> > 2) Some fs forget to zero current->journal_info on exit from vfs
> > According to call trace we have got second case. Do you use some 
> > unusual/experimental fs?
> 
> Yep, it was #2.  It turns out btrfs s setting current->journal_info 
> (for no reason that I can see?), and with the transaction ioctl a 
> transaction can span multiple calls.
> 
> Chris, is it ok to just remove the journal_info bits?  Nothing in fs/btrfs 
> even looks at it.  I'm not sure what the point of only conditionally 
> setting/clearly journal_info would be either, unless it's for debugging or 
> something?

Josef has plans to use it later on, but he sent along patches that will
avoid setting journal_info for userland trans.  I'll get these
integrated and pushed out.

-chris