RE: [PATCH] raid0: Set discard_granularity to correct value afterreshape.

[Baldysiak, Pawel]

On Thursday, October 31, 2013 1:16 AM NeilBrown <neilb@xxxxxxx> wrote:
> On Wed, 30 Oct 2013 13:20:22 +0100 Pawel Baldysiak
> <pawel.baldysiak@xxxxxxxxx> wrote:
> 
> > In case of reshape of raid0 through raid4 a value of
> > discard_granularity will be set to stripe size. MD driver should
> > re-set this value to correct one when migration will be finished.
> > Otherwise array will be left with wrong value and discard operations will not
> work properly.
> >
> > Signed-off-by: Pawel Baldysiak <pawel.baldysiak@xxxxxxxxx>
> > Cc: Shaohua Li <shli@xxxxxxxxxx>
> > ---
> >  drivers/md/raid0.c |    2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index
> > c4d420b..807ca3a 100644
> > --- a/drivers/md/raid0.c
> > +++ b/drivers/md/raid0.c
> > @@ -266,6 +266,8 @@ static int create_strip_zones(struct mddev *mddev,
> struct r0conf **private_conf)
> >  	}
> >  	mddev->queue->backing_dev_info.congested_fn = raid0_congested;
> >  	mddev->queue->backing_dev_info.congested_data = mddev;
> > +	mddev->queue->limits.discard_granularity =
> > +			queue_logical_block_size(mddev->queue);
> >
> >  	/*
> >  	 * now since we have the hard sector sizes, we can make sure
> 
> Thanks, but this doesn't seem like the right sort of fix.  It is to specific to the
> symptom rather than trying to address the underlying problem.
> 
> Maybe something like this?  Can you review and test?
> 
> Thanks,
> NeilBrown
> 
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c index
> 628cd529343f..740b6340f980 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -3620,6 +3620,7 @@ level_store(struct mddev *mddev, const char
> *buf, size_t len)
>  		mddev->in_sync = 1;
>  		del_timer_sync(&mddev->safemode_timer);
>  	}
> +	blk_set_stacking_limit(&mddev->queue->limits);
>  	pers->run(mddev);
>  	set_bit(MD_CHANGE_DEVS, &mddev->flags);
>  	mddev_resume(mddev);
Hi Neil,
I have tested Yours patch, and everything works well.
TRIM operation are made correctly.
Could You apply it to upstream? 

BTW. Correct name of this function is blk_set_stacking_limits();

Thanks,
Paweł Baldysiak
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