Re: [RFC PATCH 1/5] md: add helpers for requested sync action

在 2025/12/31 15:09, Zheng Qixing 写道:
> From: Zheng Qixing <[email protected]>
> 
> Add helpers for handling requested sync action.
> 
> In handle_requested_sync_action(), add mutual exclusivity checks between
> check/repair operations. This prevents the scenario where one operation
> is requested, but before MD_RECOVERY_RUNNING is set, another operation is
> requested, resulting in neither an EBUSY return nor proper execution of
> the second operation.
> 
> Signed-off-by: Zheng Qixing <[email protected]>
> ---
>   drivers/md/md.c | 87 +++++++++++++++++++++++++++++++++++++------------
>   1 file changed, 66 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 5df2220b1bd1..ccaa2e6fe079 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -665,6 +665,59 @@ void mddev_put(struct mddev *mddev)
>   	spin_unlock(&all_mddevs_lock);
>   }
>   
> +static int __handle_requested_sync_action(struct mddev *mddev,
> +					  enum sync_action action)
> +{
> +	switch (action) {
> +	case ACTION_CHECK:
> +		set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
> +		fallthrough;
> +	case ACTION_REPAIR:
> +		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
> +		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
> +		return 0;
> +	default:
> +		return -EINVAL;
> +	} > +}
> +
> +static int handle_requested_sync_action(struct mddev *mddev,
> +					enum sync_action action)
> +{
> +	if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
> +		return -EBUSY;

This return change origin logic; split factor out and fix into two patches.

> +	return __handle_requested_sync_action(mddev, action);
> +}
> +

__handle_requested_sync_action does not need to be split.

> +static enum sync_action __get_recovery_sync_action(struct mddev *mddev)
> +{
> +	if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
> +		return ACTION_CHECK;
> +	if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
> +		return ACTION_REPAIR;
> +	return ACTION_RESYNC;
> +}
> +
> +static enum sync_action get_recovery_sync_action(struct mddev *mddev)
> +{
> +	return __get_recovery_sync_action(mddev);
> +}
> +

__get_recovery_sync_action also does not need to be split.


> +static void init_recovery_position(struct mddev *mddev)
> +{
> +	mddev->resync_min = 0;
> +}
> +
> +static void set_requested_position(struct mddev *mddev, sector_t value)
> +{
> +	mddev->resync_min = value;
> +}
> +
> +static sector_t get_requested_position(struct mddev *mddev)
> +{
> +	return mddev->resync_min;
> +}
> +

There is no need to factor the operations of resync_min;
'rectify_min' that follows can re-use 'resync_min' directly.

>   static void md_safemode_timeout(struct timer_list *t);
>   static void md_start_sync(struct work_struct *ws);
>   
> @@ -781,7 +834,7 @@ int mddev_init(struct mddev *mddev)
>   	mddev->reshape_position = MaxSector;
>   	mddev->reshape_backwards = 0;
>   	mddev->last_sync_action = ACTION_IDLE;
> -	mddev->resync_min = 0;
> +	init_recovery_position(mddev);
>   	mddev->resync_max = MaxSector;
>   	mddev->level = LEVEL_NONE;
>   
> @@ -5101,17 +5154,9 @@ enum sync_action md_sync_action(struct mddev *mddev)
>   	if (test_bit(MD_RECOVERY_RECOVER, &recovery))
>   		return ACTION_RECOVER;
>   
> -	if (test_bit(MD_RECOVERY_SYNC, &recovery)) {
> -		/*
> -		 * MD_RECOVERY_CHECK must be paired with
> -		 * MD_RECOVERY_REQUESTED.
> -		 */
> -		if (test_bit(MD_RECOVERY_CHECK, &recovery))
> -			return ACTION_CHECK;
> -		if (test_bit(MD_RECOVERY_REQUESTED, &recovery))
> -			return ACTION_REPAIR;
> -		return ACTION_RESYNC;
> -	}
> +	/* MD_RECOVERY_CHECK must be paired with MD_RECOVERY_REQUESTED. */
> +	if (test_bit(MD_RECOVERY_SYNC, &recovery))
> +		return get_recovery_sync_action(mddev);
>   
>   	/*
>   	 * MD_RECOVERY_NEEDED or MD_RECOVERY_RUNNING is set, however, no
> @@ -5300,11 +5345,10 @@ action_store(struct mddev *mddev, const char *page, size_t len)
>   			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
>   			break;
>   		case ACTION_CHECK:
> -			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
> -			fallthrough;
>   		case ACTION_REPAIR:
> -			set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
> -			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
> +			ret = handle_requested_sync_action(mddev, action);
> +			if (ret)
> +				goto out;
>   			fallthrough;
>   		case ACTION_RESYNC:
>   		case ACTION_IDLE:
> @@ -6783,7 +6827,7 @@ static void md_clean(struct mddev *mddev)
>   	mddev->dev_sectors = 0;
>   	mddev->raid_disks = 0;
>   	mddev->resync_offset = 0;
> -	mddev->resync_min = 0;
> +	init_recovery_position(mddev);
>   	mddev->resync_max = MaxSector;
>   	mddev->reshape_position = MaxSector;
>   	/* we still need mddev->external in export_rdev, do not clear it yet */
> @@ -9370,7 +9414,7 @@ static sector_t md_sync_position(struct mddev *mddev, enum sync_action action)
>   	switch (action) {
>   	case ACTION_CHECK:
>   	case ACTION_REPAIR:
> -		return mddev->resync_min;
> +		return get_requested_position(mddev);
>   	case ACTION_RESYNC:
>   		if (!mddev->bitmap)
>   			return mddev->resync_offset;
> @@ -9795,10 +9839,11 @@ void md_do_sync(struct md_thread *thread)
>   	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
>   		/* We completed so min/max setting can be forgotten if used. */
>   		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
> -			mddev->resync_min = 0;
> +			set_requested_position(mddev, 0);
>   		mddev->resync_max = MaxSector;
> -	} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
> -		mddev->resync_min = mddev->curr_resync_completed;
> +	} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
> +		set_requested_position(mddev, mddev->curr_resync_completed);
> +	}
>   	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
>   	mddev->curr_resync = MD_RESYNC_NONE;
>   	spin_unlock(&mddev->lock);

-- 
Thanks,
Nan