Re: [PATCH] skip match_mddev_units check for special roles

[Neil Brown <neilb@suse.de>]

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Song Liu <songliubraving@fb.com> writes:

> match_mddev_units is used to check whether 2 RAID arrays share
> same disk(s). Arrays that share disk(s) will not do resync at the
> same time for better performance (fewer HDD seek). However, this
> check should not apply to Spare, Faulty, and Journal disks, as
> they do not paticipate in resync.
>
> In this patch, match_mddev_units skips check for disks with flag
> "Faulty" or "Journal" or raid_disk < 0.
>
> Signed-off-by: Song Liu <songliubraving@fb.com>
> Signed-off-by: Shaohua Li <shli@fb.com>
> ---
>  drivers/md/md.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 95824fb..b96d135 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -1957,13 +1957,23 @@ static int match_mddev_units(struct mddev *mddev1, struct mddev *mddev2)
>  	struct md_rdev *rdev, *rdev2;
>  
>  	rcu_read_lock();
> -	rdev_for_each_rcu(rdev, mddev1)
> -		rdev_for_each_rcu(rdev2, mddev2)
> +	rdev_for_each_rcu(rdev, mddev1) {
> +		if (test_bit(Faulty, &rdev->flags) ||
> +		    test_bit(Journal, &rdev->flags) ||
> +		    rdev->raid_disk == -1)
> +			continue;
> +		rdev_for_each_rcu(rdev2, mddev2) {
> +			if (test_bit(Faulty, &rdev2->flags) ||
> +			    test_bit(Journal, &rdev2->flags) ||
> +			    rdev2->raid_disk == -1)
> +				continue;
>  			if (rdev->bdev->bd_contains ==
>  			    rdev2->bdev->bd_contains) {
>  				rcu_read_unlock();
>  				return 1;
>  			}
> +		}
> +	}
>  	rcu_read_unlock();
>  	return 0;
>  }
> -- 
> 1.8.1

That makes sense.  Applied, thanks.

NeilBrown

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