On Wed, Jun 24 2009, Neil Brown wrote:
> On Sunday June 21, ken.milmore@xxxxxxxxxxxxxx wrote:
> > I thought I had better bump my previous post as this regression is still
> > present in 2.6.29.5.
>
> Thanks Ken.
>
> >
> > To recap, commit cec0707e40ae25794b5a2de7b7f03c51961f80d9 has broken
> > write barriers on md raid1 block devices in 2.6.29 and later kernels.
> > Reversing this commit appears to fix the problem.
> >
> > Please let me know if I'm harassing the wrong maintainers here!
>
> Jens,
> have you had a chance to look at this?
Yeah, I think it's the right way to go. I'll queue it up for .31 and we
should put in in -stable as well.
>
> I think the following patch is appropriate and should go in to
> -stable.
>
> Thanks,
> NeilBrown
>
>
> From addd8b129835a63d6df9a38eae20caaa15de5988 Mon Sep 17 00:00:00 2001
> From: NeilBrown <neilb@xxxxxxx>
> Date: Wed, 24 Jun 2009 13:39:15 +1000
> Subject: [PATCH] Restore barrier support for md and probably other virtual devices.
>
> The next_ordered flag is only meaningful for devices that use __make_request.
> So move the test against next_ordered out of generic code and in to
> __make_request
>
> Since this test was added, barriers have not worked on md, and (I
> think) dm and similar devices that don't use __make_request and so
> don't bother to set next_ordered.
>
> Cc: stable@xxxxxxxxxx
> Cc: Ken Milmore <ken.milmore@xxxxxxxxxxxxxx>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
> block/blk-core.c | 10 +++++-----
> 1 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index b06cf5c..fc221aa 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1172,6 +1172,11 @@ static int __make_request(struct request_queue *q, struct bio *bio)
> const int unplug = bio_unplug(bio);
> int rw_flags;
>
> + if (bio_barrier(bio) && bio_has_data(bio) &&
> + (q->next_ordered == QUEUE_ORDERED_NONE)) {
> + bio_endio(bio, -EOPNOTSUPP)
> + return 0;
> + }
> /*
> * low level driver can indicate that it wants pages above a
> * certain limit bounced to low memory (ie for highmem, or even
> @@ -1472,11 +1477,6 @@ static inline void __generic_make_request(struct bio *bio)
> err = -EOPNOTSUPP;
> goto end_io;
> }
> - if (bio_barrier(bio) && bio_has_data(bio) &&
> - (q->next_ordered == QUEUE_ORDERED_NONE)) {
> - err = -EOPNOTSUPP;
> - goto end_io;
> - }
>
> ret = q->make_request_fn(q, bio);
> } while (ret);
> --
> 1.6.3.1
>
--
Jens Axboe
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
