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Commit 05616be5 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5: Use correct data_offset for all IO. 



As there can now be two different data_offsets - an 'old' and
a 'new' - we need to carefully choose between them.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent c6563a8c

drivers/md/raid5.c

+59 −13
Original line number Diff line number Diff line
@@ -488,6 +488,27 @@ get_active_stripe(struct r5conf *conf, sector_t sector, 
	return sh;

}



/* Determine if 'data_offset' or 'new_data_offset' should be used

 * in this stripe_head.

 */

static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)

{

	sector_t progress = conf->reshape_progress;

	/* Need a memory barrier to make sure we see the value

	 * of conf->generation, or ->data_offset that was set before

	 * reshape_progress was updated.

	 */

	smp_rmb();

	if (progress == MaxSector)

		return 0;

	if (sh->generation == conf->generation - 1)

		return 0;

	/* We are in a reshape, and this is a new-generation stripe,

	 * so use new_data_offset.

	 */

	return 1;

}



static void

raid5_end_read_request(struct bio *bi, int error);

static void
@@ -603,7 +624,12 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) 
				__func__, (unsigned long long)sh->sector,

				bi->bi_rw, i);

			atomic_inc(&sh->count);

			bi->bi_sector = sh->sector + rdev->data_offset;

			if (use_new_offset(conf, sh))

				bi->bi_sector = (sh->sector

						 + rdev->new_data_offset);

			else

				bi->bi_sector = (sh->sector

						 + rdev->data_offset);

			bi->bi_flags = 1 << BIO_UPTODATE;

			bi->bi_idx = 0;

			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
@@ -627,7 +653,12 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) 
				__func__, (unsigned long long)sh->sector,

				rbi->bi_rw, i);

			atomic_inc(&sh->count);

			rbi->bi_sector = sh->sector + rrdev->data_offset;

			if (use_new_offset(conf, sh))

				rbi->bi_sector = (sh->sector

						  + rrdev->new_data_offset);

			else

				rbi->bi_sector = (sh->sector

						  + rrdev->data_offset);

			rbi->bi_flags = 1 << BIO_UPTODATE;

			rbi->bi_idx = 0;

			rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
@@ -1648,7 +1679,7 @@ static void raid5_end_read_request(struct bio * bi, int error) 
	int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags);

	char b[BDEVNAME_SIZE];

	struct md_rdev *rdev = NULL;



	sector_t s;



	for (i=0 ; i<disks; i++)

		if (bi == &sh->dev[i].req)
@@ -1671,6 +1702,10 @@ static void raid5_end_read_request(struct bio * bi, int error) 
	if (!rdev)

		rdev = conf->disks[i].rdev;



	if (use_new_offset(conf, sh))

		s = sh->sector + rdev->new_data_offset;

	else

		s = sh->sector + rdev->data_offset;

	if (uptodate) {

		set_bit(R5_UPTODATE, &sh->dev[i].flags);

		if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
@@ -1683,8 +1718,7 @@ static void raid5_end_read_request(struct bio * bi, int error) 
				"md/raid:%s: read error corrected"

				" (%lu sectors at %llu on %s)\n",

				mdname(conf->mddev), STRIPE_SECTORS,

				(unsigned long long)(sh->sector

						     + rdev->data_offset),

				(unsigned long long)s,

				bdevname(rdev->bdev, b));

			atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);

			clear_bit(R5_ReadError, &sh->dev[i].flags);
@@ -1704,8 +1738,7 @@ static void raid5_end_read_request(struct bio * bi, int error) 
				"md/raid:%s: read error on replacement device "

				"(sector %llu on %s).\n",

				mdname(conf->mddev),

				(unsigned long long)(sh->sector

						     + rdev->data_offset),

				(unsigned long long)s,

				bdn);

		else if (conf->mddev->degraded >= conf->max_degraded)

			printk_ratelimited(
@@ -1713,8 +1746,7 @@ static void raid5_end_read_request(struct bio * bi, int error) 
				"md/raid:%s: read error not correctable "

				"(sector %llu on %s).\n",

				mdname(conf->mddev),

				(unsigned long long)(sh->sector

						     + rdev->data_offset),

				(unsigned long long)s,

				bdn);

		else if (test_bit(R5_ReWrite, &sh->dev[i].flags))

			/* Oh, no!!! */
@@ -1723,8 +1755,7 @@ static void raid5_end_read_request(struct bio * bi, int error) 
				"md/raid:%s: read error NOT corrected!! "

				"(sector %llu on %s).\n",

				mdname(conf->mddev),

				(unsigned long long)(sh->sector

						     + rdev->data_offset),

				(unsigned long long)s,

				bdn);

		else if (atomic_read(&rdev->read_errors)

			 > conf->max_nr_stripes)
@@ -3842,6 +3873,7 @@ static int chunk_aligned_read(struct mddev *mddev, struct bio * raid_bio) 
		raid_bio->bi_next = (void*)rdev;

		align_bi->bi_bdev =  rdev->bdev;

		align_bi->bi_flags &= ~(1 << BIO_SEG_VALID);

		/* No reshape active, so we can trust rdev->data_offset */

		align_bi->bi_sector += rdev->data_offset;



		if (!bio_fits_rdev(align_bi) ||
@@ -5182,9 +5214,12 @@ static int run(struct mddev *mddev) 
		blk_queue_io_opt(mddev->queue, chunk_size *

				 (conf->raid_disks - conf->max_degraded));



		rdev_for_each(rdev, mddev)

		rdev_for_each(rdev, mddev) {

			disk_stack_limits(mddev->gendisk, rdev->bdev,

					  rdev->data_offset << 9);

			disk_stack_limits(mddev->gendisk, rdev->bdev,

					  rdev->new_data_offset << 9);

		}

	}



	return 0;
@@ -5539,12 +5574,16 @@ static int raid5_start_reshape(struct mddev *mddev) 
	conf->chunk_sectors = mddev->new_chunk_sectors;

	conf->prev_algo = conf->algorithm;

	conf->algorithm = mddev->new_layout;

	conf->generation++;

	/* Code that selects data_offset needs to see the generation update

	 * if reshape_progress has been set - so a memory barrier needed.

	 */

	smp_mb();

	if (mddev->reshape_backwards)

		conf->reshape_progress = raid5_size(mddev, 0, 0);

	else

		conf->reshape_progress = 0;

	conf->reshape_safe = conf->reshape_progress;

	conf->generation++;

	spin_unlock_irq(&conf->device_lock);



	/* Add some new drives, as many as will fit.
@@ -5596,6 +5635,9 @@ static int raid5_start_reshape(struct mddev *mddev) 
		mddev->recovery = 0;

		spin_lock_irq(&conf->device_lock);

		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;

		rdev_for_each(rdev, mddev)

			rdev->new_data_offset = rdev->data_offset;

		smp_wmb();

		conf->reshape_progress = MaxSector;

		mddev->reshape_position = MaxSector;

		spin_unlock_irq(&conf->device_lock);
@@ -5614,9 +5656,13 @@ static void end_reshape(struct r5conf *conf) 
{



	if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {

		struct md_rdev *rdev;



		spin_lock_irq(&conf->device_lock);

		conf->previous_raid_disks = conf->raid_disks;

		rdev_for_each(rdev, conf->mddev)

			rdev->data_offset = rdev->new_data_offset;

		smp_wmb();

		conf->reshape_progress = MaxSector;

		spin_unlock_irq(&conf->device_lock);

		wake_up(&conf->wait_for_overlap);