On Sunday June 21, [email protected] 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?
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 <[email protected]>
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: [email protected]
Cc: Ken Milmore <[email protected]>
Signed-off-by: NeilBrown <[email protected]>
---
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
On Wed, Jun 24, 2009 at 01:43:35PM +1000, Neil Brown wrote:
> 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.
In dm, we added this:
+ blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL);
Alasdair
On Wed, June 24, 2009 5:09 pm, Alasdair G Kergon wrote:
> On Wed, Jun 24, 2009 at 01:43:35PM +1000, Neil Brown wrote:
>> 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.
>
> In dm, we added this:
>
> + blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL);
>
I obviously didn't grep for the right thing.
This will obviously work, but I can't help thinking it is in the wrong
place. I don't even have a queue in md/raid1, so making a statement
about how it is ordered just doesn't make sense.
Jens?
NeilBrown
On Wed, Jun 24 2009, Neil Brown wrote:
> On Sunday June 21, [email protected] 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 <[email protected]>
> 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: [email protected]
> Cc: Ken Milmore <[email protected]>
> Signed-off-by: NeilBrown <[email protected]>
> ---
> 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