Bug#615998: linux-image-2.6.32-5-xen-amd64: Repeatable "kernel BUG at fs/jbd2/commit.c:534" from Postfix on ext4

[Amir Goldstein <amir73il@gmail.com>]

On Mon, Jun 27, 2011 at 2:16 PM, Lukas Czerner <lczerner@redhat.com> wrote:
> On Fri, 24 Jun 2011, Jan Kara wrote:
>
>> On Fri 24-06-11 11:03:52, Moffett, Kyle D wrote:
>> > On Jun 24, 2011, at 09:46, Jan Kara wrote:
>> > > On Thu 23-06-11 16:19:08, Moffett, Kyle D wrote:
>> > >> Besides which, line 534 in the Debian 2.6.32 kernel I am using is this
>> > >> one:
>> > >>
>> > >>  J_ASSERT(commit_transaction->t_nr_buffers <=
>> > >>           commit_transaction->t_outstanding_credits);
>> > >
>> > >  Hmm, OK, so we've used more metadata buffers than we told JBD2 to
>> > > reserve. I suppose you are not using data=journal mode and the filesystem
>> > > was created as ext4 (i.e. not converted from ext3), right? Are you using
>> > > quotas?
>> >
>> > The filesystem *is* using data=journal mode.  If I switch to data=ordered
>> > or data=writeback, the problem goes away.
>>   Ah, OK. Then bug https://bugzilla.kernel.org/show_bug.cgi?id=34642 is
>> probably ext3 incarnation of the same problem and it seems it's still
>> present even in the current kernel - that ext3 assertion triggered even
>> with 2.6.39 kernel. Frankly data=journal mode is far less tested than the
>> other two modes especially with ext4, so I'm not sure how good idea is to
>> use it in production.
>
> Hi Jan,
>
> if it is so (and it probably is, since I am not testing this mode as
> well:), it would be interesting to find out whether there are many users
> of this and if there are not, which is probably the case, deprecate it now,
> so we can remove it later. If we are openly suggesting not to use this,
> then there is probably no point in having this option in the first
> place.
>
> I vaguely remember that Ted said something about removing data=journal
> mode, but I do not remember details. Ted ?
>

I think Ted was plotting about removing data=ordered...

Amir.