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?
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
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