Re: 2.6.15-mm2

From: Jens Axboe
Date: Wed Jan 11 2006 - 14:42:48 EST


On Thu, Jan 12 2006, Reuben Farrelly wrote:
>
>
> On 12/01/2006 3:55 a.m., Jens Axboe wrote:
> >On Wed, Jan 11 2006, Jens Axboe wrote:
> >>It's not too tricky, you just need to correct that function prototype.
> >>Could you do that? Would be nice to know _exactly_ which libata
> >>changeset caused this malfunction. But it does of course point at the
> >>barrier changes for scsi/libata...
> >
> >You can also try something quicker - use a newer kernel known to exhibit
> >the problem, and apply this patch on top of that:
> >
> >diff --git a/drivers/md/md.c b/drivers/md/md.c
> >index 0302723..720ace4 100644
> >--- a/drivers/md/md.c
> >+++ b/drivers/md/md.c
> >@@ -436,6 +436,7 @@ void md_super_write(mddev_t *mddev, mdk_
> > bio->bi_rw = rw;
> >
> > atomic_inc(&mddev->pending_writes);
> >+#if 0
> > if (!test_bit(BarriersNotsupp, &rdev->flags)) {
> > struct bio *rbio;
> > rw |= (1<<BIO_RW_BARRIER);
> >@@ -444,6 +445,7 @@ void md_super_write(mddev_t *mddev, mdk_
> > rbio->bi_end_io = super_written_barrier;
> > submit_bio(rw, rbio);
> > } else
> >+#endif
> > submit_bio(rw, bio);
> > }
>
> ...and with that patch, I can now boot up 2.6.15-mm3 (repeated twice). So
> yes, looks like that's where the problem lies.

At least it shows that the problem is indeed barrier related. I don't
have the start of this thread, so can you please send me the output from
dmesg from this kernel boot? I'm curious whether the fallback triggers,
or if it's the barrier that fails instead.

--
Jens Axboe

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