linux-kernel - Re: [PATCH md-6.10 8/9] md: factor out helpers for different sync_action in md_do

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Date: Tue, 14 May 2024 15:27:56 +0800
From: Xiao Ni <xni@...hat.com>
To: Yu Kuai <yukuai1@...weicloud.com>, agk@...hat.com, snitzer@...nel.org,
 mpatocka@...hat.com, song@...nel.org
Cc: dm-devel@...ts.linux.dev, linux-kernel@...r.kernel.org,
 linux-raid@...r.kernel.org, yukuai3@...wei.com, yi.zhang@...wei.com,
 yangerkun@...wei.com
Subject: Re: [PATCH md-6.10 8/9] md: factor out helpers for different
 sync_action in md_do_sync()


在 2024/5/9 上午9:18, Yu Kuai 写道:
> From: Yu Kuai <yukuai3@...wei.com>
>
> Make code cleaner by replace if else if with switch, and it's more
> obvious now what is doning for each sync_action. There are no

Hi Kuai

type error s/doning/doing/g

Regards

Xiao

> functional changes.
>
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
> ---
>   drivers/md/md.c | 123 ++++++++++++++++++++++++++++--------------------
>   1 file changed, 73 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 2fc81175b46b..42db128b82d9 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -8928,6 +8928,77 @@ void md_allow_write(struct mddev *mddev)
>   }
>   EXPORT_SYMBOL_GPL(md_allow_write);
>   
> +static sector_t md_sync_max_sectors(struct mddev *mddev,
> +				    enum sync_action action)
> +{
> +	switch (action) {
> +	case ACTION_RESYNC:
> +	case ACTION_CHECK:
> +	case ACTION_REPAIR:
> +		atomic64_set(&mddev->resync_mismatches, 0);
> +		fallthrough;
> +	case ACTION_RESHAPE:
> +		return mddev->resync_max_sectors;
> +	case ACTION_RECOVER:
> +		return mddev->dev_sectors;
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static sector_t md_sync_position(struct mddev *mddev, enum sync_action action)
> +{
> +	sector_t start = 0;
> +	struct md_rdev *rdev;
> +
> +	switch (action) {
> +	case ACTION_CHECK:
> +	case ACTION_REPAIR:
> +		return mddev->resync_min;
> +	case ACTION_RESYNC:
> +		if (!mddev->bitmap)
> +			return mddev->recovery_cp;
> +		return 0;
> +	case ACTION_RESHAPE:
> +		/*
> +		 * If the original node aborts reshaping then we continue the
> +		 * reshaping, so set again to avoid restart reshape from the
> +		 * first beginning
> +		 */
> +		if (mddev_is_clustered(mddev) &&
> +		    mddev->reshape_position != MaxSector)
> +			return mddev->reshape_position;
> +		return 0;
> +	case ACTION_RECOVER:
> +		start = MaxSector;
> +		rcu_read_lock();
> +		rdev_for_each_rcu(rdev, mddev)
> +			if (rdev->raid_disk >= 0 &&
> +			    !test_bit(Journal, &rdev->flags) &&
> +			    !test_bit(Faulty, &rdev->flags) &&
> +			    !test_bit(In_sync, &rdev->flags) &&
> +			    rdev->recovery_offset < start)
> +				start = rdev->recovery_offset;
> +		rcu_read_unlock();
> +
> +		/* If there is a bitmap, we need to make sure all
> +		 * writes that started before we added a spare
> +		 * complete before we start doing a recovery.
> +		 * Otherwise the write might complete and (via
> +		 * bitmap_endwrite) set a bit in the bitmap after the
> +		 * recovery has checked that bit and skipped that
> +		 * region.
> +		 */
> +		if (mddev->bitmap) {
> +			mddev->pers->quiesce(mddev, 1);
> +			mddev->pers->quiesce(mddev, 0);
> +		}
> +		return start;
> +	default:
> +		return MaxSector;
> +	}
> +}
> +
>   #define SYNC_MARKS	10
>   #define	SYNC_MARK_STEP	(3*HZ)
>   #define UPDATE_FREQUENCY (5*60*HZ)
> @@ -9046,56 +9117,8 @@ void md_do_sync(struct md_thread *thread)
>   		spin_unlock(&all_mddevs_lock);
>   	} while (mddev->curr_resync < MD_RESYNC_DELAYED);
>   
> -	j = 0;
> -	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
> -		/* resync follows the size requested by the personality,
> -		 * which defaults to physical size, but can be virtual size
> -		 */
> -		max_sectors = mddev->resync_max_sectors;
> -		atomic64_set(&mddev->resync_mismatches, 0);
> -		/* we don't use the checkpoint if there's a bitmap */
> -		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
> -			j = mddev->resync_min;
> -		else if (!mddev->bitmap)
> -			j = mddev->recovery_cp;
> -
> -	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
> -		max_sectors = mddev->resync_max_sectors;
> -		/*
> -		 * If the original node aborts reshaping then we continue the
> -		 * reshaping, so set j again to avoid restart reshape from the
> -		 * first beginning
> -		 */
> -		if (mddev_is_clustered(mddev) &&
> -		    mddev->reshape_position != MaxSector)
> -			j = mddev->reshape_position;
> -	} else {
> -		/* recovery follows the physical size of devices */
> -		max_sectors = mddev->dev_sectors;
> -		j = MaxSector;
> -		rcu_read_lock();
> -		rdev_for_each_rcu(rdev, mddev)
> -			if (rdev->raid_disk >= 0 &&
> -			    !test_bit(Journal, &rdev->flags) &&
> -			    !test_bit(Faulty, &rdev->flags) &&
> -			    !test_bit(In_sync, &rdev->flags) &&
> -			    rdev->recovery_offset < j)
> -				j = rdev->recovery_offset;
> -		rcu_read_unlock();
> -
> -		/* If there is a bitmap, we need to make sure all
> -		 * writes that started before we added a spare
> -		 * complete before we start doing a recovery.
> -		 * Otherwise the write might complete and (via
> -		 * bitmap_endwrite) set a bit in the bitmap after the
> -		 * recovery has checked that bit and skipped that
> -		 * region.
> -		 */
> -		if (mddev->bitmap) {
> -			mddev->pers->quiesce(mddev, 1);
> -			mddev->pers->quiesce(mddev, 0);
> -		}
> -	}
> +	max_sectors = md_sync_max_sectors(mddev, action);
> +	j = md_sync_position(mddev, action);
>   
>   	pr_info("md: %s of RAID array %s\n", desc, mdname(mddev));
>   	pr_debug("md: minimum _guaranteed_  speed: %d KB/sec/disk.\n", speed_min(mddev));