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Commit 23da422b authored by NeilBrown's avatar NeilBrown
Browse files

md: use mddev->lock to protect updates to resync_{min,max}. 



There are interdependencies between these two sysfs attributes
and whether a resync is currently running.

Rather than depending on reconfig_mutex to ensure no races when
testing these interdependencies are met, use the spinlock.
This will allow the mutex to be remove from protecting this
code in a subsequent patch.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 1b30e66f

drivers/md/md.c

+45 −13
Original line number Diff line number Diff line
@@ -4269,22 +4269,36 @@ static ssize_t 
min_sync_store(struct mddev *mddev, const char *buf, size_t len)

{

	unsigned long long min;

	int err;

	int chunk;



	if (kstrtoull(buf, 10, &min))

		return -EINVAL;



	spin_lock(&mddev->lock);

	err = -EINVAL;

	if (min > mddev->resync_max)

		return -EINVAL;

		goto out_unlock;



	err = -EBUSY;

	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))

		return -EBUSY;

		goto out_unlock;



	/* Must be a multiple of chunk_size */

	if (mddev->chunk_sectors) {

	chunk = mddev->chunk_sectors;

	if (chunk) {

		sector_t temp = min;

		if (sector_div(temp, mddev->chunk_sectors))

			return -EINVAL;



		err = -EINVAL;

		if (sector_div(temp, chunk))

			goto out_unlock;

	}

	mddev->resync_min = min;

	err = 0;



	return len;

out_unlock:

	spin_unlock(&mddev->lock);

	return err ?: len;

}



static struct md_sysfs_entry md_min_sync =
@@ -4302,29 +4316,42 @@ max_sync_show(struct mddev *mddev, char *page) 
static ssize_t

max_sync_store(struct mddev *mddev, const char *buf, size_t len)

{

	int err;

	spin_lock(&mddev->lock);

	if (strncmp(buf, "max", 3) == 0)

		mddev->resync_max = MaxSector;

	else {

		unsigned long long max;

		int chunk;



		err = -EINVAL;

		if (kstrtoull(buf, 10, &max))

			return -EINVAL;

			goto out_unlock;

		if (max < mddev->resync_min)

			return -EINVAL;

			goto out_unlock;



		err = -EBUSY;

		if (max < mddev->resync_max &&

		    mddev->ro == 0 &&

		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))

			return -EBUSY;

			goto out_unlock;



		/* Must be a multiple of chunk_size */

		if (mddev->chunk_sectors) {

		chunk = mddev->chunk_sectors;

		if (chunk) {

			sector_t temp = max;

			if (sector_div(temp, mddev->chunk_sectors))

				return -EINVAL;



			err = -EINVAL;

			if (sector_div(temp, chunk))

				goto out_unlock;

		}

		mddev->resync_max = max;

	}

	wake_up(&mddev->recovery_wait);

	return len;

	err = 0;

out_unlock:

	spin_unlock(&mddev->lock);

	return err ?: len;

}



static struct md_sysfs_entry md_max_sync =
@@ -7585,6 +7612,7 @@ void md_do_sync(struct md_thread *thread) 
 skip:

	set_bit(MD_CHANGE_DEVS, &mddev->flags);



	spin_lock(&mddev->lock);

	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))
@@ -7593,6 +7621,8 @@ void md_do_sync(struct md_thread *thread) 
	} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))

		mddev->resync_min = mddev->curr_resync_completed;

	mddev->curr_resync = 0;

	spin_unlock(&mddev->lock);



	wake_up(&resync_wait);

	set_bit(MD_RECOVERY_DONE, &mddev->recovery);

	md_wakeup_thread(mddev->thread);
@@ -7793,7 +7823,9 @@ void md_check_recovery(struct mddev *mddev) 
		 * any transients in the value of "sync_action".

		 */

		mddev->curr_resync_completed = 0;

		spin_lock(&mddev->lock);

		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);

		spin_unlock(&mddev->lock);

		/* Clear some bits that don't mean anything, but

		 * might be left set

		 */

drivers/md/md.h

+2 −0
Original line number Diff line number Diff line
@@ -394,6 +394,8 @@ struct mddev { 
	 *   pers (also protected by reconfig_mutex and pending IO).

	 *   clearing ->bitmap

	 *   clearing ->bitmap_info.file

	 *   changing ->resync_{min,max}

	 *   setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max})

	 */

	spinlock_t			lock;

	wait_queue_head_t		sb_wait;	/* for waiting on superblock updates */