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

[Ted Ts'o <tytso@mit.edu>]

On Tue, Apr 05, 2011 at 10:30:11AM -0500, Moffett, Kyle D wrote:
> > Couple of questions which might give me some clues:
> >   (a) was this a natively formatted ext4 file system, or a ext3 file
> >       system which was later converted to ext4?
> 
> All the filesystems were formatted like this using Debian e2fstools
> as of 9 months ago:

Rats.  OK, so the indirect block journal credit bug fix won't help
this bug.

>   mke2fs -t ext4 -E lazy_itable_init=1 -L db:mail /dev/mapper/db-mail
>   tune2fs -i 0 -c 1 -e remount-ro -o acl,user_xattr,journal_data /dev/mapper/db-mail
> 
> Ooooh.... could the lazy_itable_init have anything to do with it?

Shouldn't be, since 2.6.32 doesn't have the lazy inode init support.
That support didn't show up until 2.6.37.

> I've switched the relevant filesystems back to data=journal mode,
> so if you want to send me a patch for 2.6.32 that I can apply to a
> Debian kernel I will keep that kernel around and if I see it happen
> again I'll check if the patch fixes it.

Given that this was a freshly created file system with mke2fs -t ext4,
I doubt the patch would help.

> Well, the base image is essentially a somewhat basic Debian "squeeze"
> for EC2 with our SSH public keys and a couple generic customizations
> applied.  It does not have Postfix installed or configured, so there
> would be some work involved.

Well, if you can share that image in AWS with the ssh keys stripped
out it would save me a bunch of time.  I assume it's not setup to
automatically set ssh keys and pass them back to AWS like the generic
images can?

> I also didn't see any problems with the system at all until the
> queue got backed up with ~100-120 stuck emails.  After Postfix tried
> and failed to deliver a bunch of emails I would get the OOPS.

Yeah, what I'd probably try to do is install postfix and then send a
few hundred messages to foobar@example.com and see if I can repro the OOPS.

Thanks for investigating!

						- Ted