Commit 784052ec authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5: prepare for allowing reshape to change chunksize. 



Add "prev_chunk" to raid5_conf_t, similar to "previous_raid_disks", to
remember what the chunk size was before the reshape that is currently
underway.

This seems like duplication with "chunk_size" and "new_chunk" in
mddev_t, and to some extent it is, but there are differences.
The values in mddev_t are always defined and often the same.
The prev* values are only defined if a reshape is underway.

Also (and more significantly) the raid5_conf_t values will be changed
at the same time (inside an appropriate lock) that the reshape is
started by setting reshape_position.  In contrast, the new_chunk value
is set when the sysfs file is written which could be well before the
reshape starts.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 86b42c71

drivers/md/raid5.c

+27 −16
Original line number Diff line number Diff line
@@ -299,7 +299,7 @@ static int grow_buffers(struct stripe_head *sh, int num) 
	return 0;

}



static void raid5_build_block(struct stripe_head *sh, int i);

static void raid5_build_block(struct stripe_head *sh, int i, int previous);

static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,

			    struct stripe_head *sh);
@@ -337,7 +337,7 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int previous) 
			BUG();

		}

		dev->flags = 0;

		raid5_build_block(sh, i);

		raid5_build_block(sh, i, previous);

	}

	insert_hash(conf, sh);

}
@@ -1212,9 +1212,9 @@ static void raid5_end_write_request(struct bio *bi, int error) 
}





static sector_t compute_blocknr(struct stripe_head *sh, int i);

static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous);

	

static void raid5_build_block(struct stripe_head *sh, int i)

static void raid5_build_block(struct stripe_head *sh, int i, int previous)

{

	struct r5dev *dev = &sh->dev[i];
@@ -1230,7 +1230,7 @@ static void raid5_build_block(struct stripe_head *sh, int i) 
	dev->req.bi_private = sh;



	dev->flags = 0;

	dev->sector = compute_blocknr(sh, i);

	dev->sector = compute_blocknr(sh, i, previous);

}



static void error(mddev_t *mddev, mdk_rdev_t *rdev)
@@ -1273,7 +1273,8 @@ static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector, 
	int pd_idx, qd_idx;

	int ddf_layout = 0;

	sector_t new_sector;

	int sectors_per_chunk = conf->chunk_size >> 9;

	int sectors_per_chunk = previous ? (conf->prev_chunk >> 9)

					 : (conf->chunk_size >> 9);

	int raid_disks = previous ? conf->previous_raid_disks

				  : conf->raid_disks;

	int data_disks = raid_disks - conf->max_degraded;
@@ -1472,13 +1473,14 @@ static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector, 
}





static sector_t compute_blocknr(struct stripe_head *sh, int i)

static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)

{

	raid5_conf_t *conf = sh->raid_conf;

	int raid_disks = sh->disks;

	int data_disks = raid_disks - conf->max_degraded;

	sector_t new_sector = sh->sector, check;

	int sectors_per_chunk = conf->chunk_size >> 9;

	int sectors_per_chunk = previous ? (conf->prev_chunk >> 9)

					 : (conf->chunk_size >> 9);

	sector_t stripe;

	int chunk_offset;

	int chunk_number, dummy1, dd_idx = i;
@@ -1579,8 +1581,7 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i) 
	r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;



	check = raid5_compute_sector(conf, r_sector,

				     (raid_disks != conf->raid_disks),

				     &dummy1, &sh2);

				     previous, &dummy1, &sh2);

	if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx

		|| sh2.qd_idx != sh->qd_idx) {

		printk(KERN_ERR "compute_blocknr: map not correct\n");
@@ -1992,7 +1993,9 @@ static int page_is_zero(struct page *p) 
static void stripe_set_idx(sector_t stripe, raid5_conf_t *conf, int previous,

			    struct stripe_head *sh)

{

	int sectors_per_chunk = conf->chunk_size >> 9;

	int sectors_per_chunk =

		previous ? (conf->prev_chunk >> 9)

			 : (conf->chunk_size >> 9);

	int dd_idx;

	int chunk_offset = sector_div(stripe, sectors_per_chunk);

	int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
@@ -2662,7 +2665,7 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh, 
			int dd_idx, j;

			struct stripe_head *sh2;



			sector_t bn = compute_blocknr(sh, i);

			sector_t bn = compute_blocknr(sh, i, 1);

			sector_t s = raid5_compute_sector(conf, bn, 0,

							  &dd_idx, NULL);

			sh2 = get_active_stripe(conf, s, 0, 1);
@@ -3318,6 +3321,8 @@ static int raid5_mergeable_bvec(struct request_queue *q, 
	if ((bvm->bi_rw & 1) == WRITE)

		return biovec->bv_len; /* always allow writes to be mergeable */



	if (mddev->new_chunk < mddev->chunk_size)

		chunk_sectors = mddev->new_chunk >> 9;

	max =  (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;

	if (max < 0) max = 0;

	if (max <= biovec->bv_len && bio_sectors == 0)
@@ -3333,6 +3338,8 @@ static int in_chunk_boundary(mddev_t *mddev, struct bio *bio) 
	unsigned int chunk_sectors = mddev->chunk_size >> 9;

	unsigned int bio_sectors = bio->bi_size >> 9;



	if (mddev->new_chunk < mddev->chunk_size)

		chunk_sectors = mddev->new_chunk >> 9;

	return  chunk_sectors >=

		((sector & (chunk_sectors - 1)) + bio_sectors);

}
@@ -3788,7 +3795,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped 
		BUG_ON(conf->reshape_progress == 0);

		stripe_addr = writepos;

		BUG_ON((mddev->dev_sectors &

			~((sector_t)mddev->chunk_size / 512 - 1))

			~((sector_t)conf->chunk_size / 512 - 1))

		       - (conf->chunk_size / 512) - stripe_addr

		       != sector_nr);

	} else {
@@ -3811,7 +3818,7 @@ static sector_t reshape_request(mddev_t *mddev, sector_t sector_nr, int *skipped 
			if (conf->level == 6 &&

			    j == sh->qd_idx)

				continue;

			s = compute_blocknr(sh, j);

			s = compute_blocknr(sh, j, 0);

			if (s < raid5_size(mddev, 0, 0)) {

				skipped = 1;

				continue;
@@ -4217,6 +4224,7 @@ raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks) 
	}



	sectors &= ~((sector_t)mddev->chunk_size/512 - 1);

	sectors &= ~((sector_t)mddev->new_chunk/512 - 1);

	return sectors * (raid_disks - conf->max_degraded);

}
@@ -4322,6 +4330,8 @@ static raid5_conf_t *setup_conf(mddev_t *mddev) 
	conf->algorithm = mddev->new_layout;

	conf->max_nr_stripes = NR_STRIPES;

	conf->reshape_progress = mddev->reshape_position;

	if (conf->reshape_progress != MaxSector)

		conf->prev_chunk = mddev->chunk_size;



	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +

		 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
@@ -4385,7 +4395,7 @@ static int run(mddev_t *mddev) 
		 * geometry.

		 */

		here_new = mddev->reshape_position;

		if (sector_div(here_new, (mddev->chunk_size>>9)*

		if (sector_div(here_new, (mddev->new_chunk>>9)*

			       (mddev->raid_disks - max_degraded))) {

			printk(KERN_ERR "raid5: reshape_position not "

			       "on a stripe boundary\n");
@@ -4789,7 +4799,8 @@ static int raid5_check_reshape(mddev_t *mddev) 
	if ((mddev->chunk_size / STRIPE_SIZE) * 4 > conf->max_nr_stripes ||

	    (mddev->new_chunk / STRIPE_SIZE) * 4 > conf->max_nr_stripes) {

		printk(KERN_WARNING "raid5: reshape: not enough stripes.  Needed %lu\n",

		       (mddev->chunk_size / STRIPE_SIZE)*4);

		       (max(mddev->chunk_size, mddev->new_chunk)

			/ STRIPE_SIZE)*4);

		return -ENOSPC;

	}

drivers/md/raid5.h

+1 −0
Original line number Diff line number Diff line
@@ -350,6 +350,7 @@ struct raid5_private_data { 
	 */

	sector_t		reshape_safe;

	int			previous_raid_disks;

	int			prev_chunk;

	short			generation; /* increments with every reshape */



	struct list_head	handle_list; /* stripes needing handling */

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