Commit 3c2f765c authored by Jens Axboe's avatar Jens Axboe
Browse files

Merge tag 'md-fixes-20230630' of... 

Merge tag 'md-fixes-20230630' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into block-6.5

Pull MD fix from Song:

"This patch fixes data corruption caused by discard on raid0 array with
 original layout."

* tag 'md-fixes-20230630' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md/raid0: add discard support for the 'original' layout
parents 6e34e784 e8360070

drivers/md/raid0.c

+54 −8
Original line number Diff line number Diff line
@@ -270,6 +270,18 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) 
		goto abort;

	}



	if (conf->layout == RAID0_ORIG_LAYOUT) {

		for (i = 1; i < conf->nr_strip_zones; i++) {

			sector_t first_sector = conf->strip_zone[i-1].zone_end;



			sector_div(first_sector, mddev->chunk_sectors);

			zone = conf->strip_zone + i;

			/* disk_shift is first disk index used in the zone */

			zone->disk_shift = sector_div(first_sector,

						      zone->nb_dev);

		}

	}



	pr_debug("md/raid0:%s: done.\n", mdname(mddev));

	*private_conf = conf;
@@ -431,6 +443,20 @@ static int raid0_run(struct mddev *mddev) 
	return ret;

}



/*

 * Convert disk_index to the disk order in which it is read/written.

 *  For example, if we have 4 disks, they are numbered 0,1,2,3. If we

 *  write the disks starting at disk 3, then the read/write order would

 *  be disk 3, then 0, then 1, and then disk 2 and we want map_disk_shift()

 *  to map the disks as follows 0,1,2,3 => 1,2,3,0. So disk 0 would map

 *  to 1, 1 to 2, 2 to 3, and 3 to 0. That way we can compare disks in

 *  that 'output' space to understand the read/write disk ordering.

 */

static int map_disk_shift(int disk_index, int num_disks, int disk_shift)

{

	return ((disk_index + num_disks - disk_shift) % num_disks);

}



static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)

{

	struct r0conf *conf = mddev->private;
@@ -444,7 +470,9 @@ static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) 
	sector_t end_disk_offset;

	unsigned int end_disk_index;

	unsigned int disk;

	sector_t orig_start, orig_end;



	orig_start = start;

	zone = find_zone(conf, &start);



	if (bio_end_sector(bio) > zone->zone_end) {
@@ -458,6 +486,7 @@ static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) 
	} else

		end = bio_end_sector(bio);



	orig_end = end;

	if (zone != conf->strip_zone)

		end = end - zone[-1].zone_end;
@@ -469,13 +498,26 @@ static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) 
	last_stripe_index = end;

	sector_div(last_stripe_index, stripe_size);



	/* In the first zone the original and alternate layouts are the same */

	if ((conf->layout == RAID0_ORIG_LAYOUT) && (zone != conf->strip_zone)) {

		sector_div(orig_start, mddev->chunk_sectors);

		start_disk_index = sector_div(orig_start, zone->nb_dev);

		start_disk_index = map_disk_shift(start_disk_index,

						  zone->nb_dev,

						  zone->disk_shift);

		sector_div(orig_end, mddev->chunk_sectors);

		end_disk_index = sector_div(orig_end, zone->nb_dev);

		end_disk_index = map_disk_shift(end_disk_index,

						zone->nb_dev, zone->disk_shift);

	} else {

		start_disk_index = (int)(start - first_stripe_index * stripe_size) /

			mddev->chunk_sectors;

		end_disk_index = (int)(end - last_stripe_index * stripe_size) /

			mddev->chunk_sectors;

	}

	start_disk_offset = ((int)(start - first_stripe_index * stripe_size) %

		mddev->chunk_sectors) +

		first_stripe_index * mddev->chunk_sectors;

	end_disk_index = (int)(end - last_stripe_index * stripe_size) /

		mddev->chunk_sectors;

	end_disk_offset = ((int)(end - last_stripe_index * stripe_size) %

		mddev->chunk_sectors) +

		last_stripe_index * mddev->chunk_sectors;
@@ -483,18 +525,22 @@ static void raid0_handle_discard(struct mddev *mddev, struct bio *bio) 
	for (disk = 0; disk < zone->nb_dev; disk++) {

		sector_t dev_start, dev_end;

		struct md_rdev *rdev;

		int compare_disk;



		compare_disk = map_disk_shift(disk, zone->nb_dev,

					      zone->disk_shift);



		if (disk < start_disk_index)

		if (compare_disk < start_disk_index)

			dev_start = (first_stripe_index + 1) *

				mddev->chunk_sectors;

		else if (disk > start_disk_index)

		else if (compare_disk > start_disk_index)

			dev_start = first_stripe_index * mddev->chunk_sectors;

		else

			dev_start = start_disk_offset;



		if (disk < end_disk_index)

		if (compare_disk < end_disk_index)

			dev_end = (last_stripe_index + 1) * mddev->chunk_sectors;

		else if (disk > end_disk_index)

		else if (compare_disk > end_disk_index)

			dev_end = last_stripe_index * mddev->chunk_sectors;

		else

			dev_end = end_disk_offset;

drivers/md/raid0.h

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ struct strip_zone { 
	sector_t zone_end;	/* Start of the next zone (in sectors) */

	sector_t dev_start;	/* Zone offset in real dev (in sectors) */

	int	 nb_dev;	/* # of devices attached to the zone */

	int	 disk_shift;	/* start disk for the original layout */

};



/* Linux 3.14 (20d0189b101) made an unintended change to