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Commit 35f2a591 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5: allow for more than 2^31 chunks. 



With many large drives and small chunk sizes it is possible
to create a RAID5 with more than 2^31 chunks.  Make sure this
works.

Reported-by: default avatarBrett King <king.br@gmail.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Cc: stable@kernel.org
parent 85341c61

drivers/md/raid5.c

+7 −12
Original line number Diff line number Diff line
@@ -1650,8 +1650,8 @@ static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector, 
				     int previous, int *dd_idx,

				     struct stripe_head *sh)

{

	long stripe;

	unsigned long chunk_number;

	sector_t stripe;

	sector_t chunk_number;

	unsigned int chunk_offset;

	int pd_idx, qd_idx;

	int ddf_layout = 0;
@@ -1671,17 +1671,12 @@ static sector_t raid5_compute_sector(raid5_conf_t *conf, sector_t r_sector, 
	 */

	chunk_offset = sector_div(r_sector, sectors_per_chunk);

	chunk_number = r_sector;

	BUG_ON(r_sector != chunk_number);



	/*

	 * Compute the stripe number

	 */

	stripe = chunk_number / data_disks;



	/*

	 * Compute the data disk and parity disk indexes inside the stripe

	 */

	*dd_idx = chunk_number % data_disks;

	stripe = chunk_number;

	*dd_idx = sector_div(stripe, data_disks);



	/*

	 * Select the parity disk based on the user selected algorithm.
@@ -1870,14 +1865,14 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous) 
				 : conf->algorithm;

	sector_t stripe;

	int chunk_offset;

	int chunk_number, dummy1, dd_idx = i;

	sector_t chunk_number;

	int dummy1, dd_idx = i;

	sector_t r_sector;

	struct stripe_head sh2;





	chunk_offset = sector_div(new_sector, sectors_per_chunk);

	stripe = new_sector;

	BUG_ON(new_sector != stripe);



	if (i == sh->pd_idx)

		return 0;
@@ -1970,7 +1965,7 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous) 
	}



	chunk_number = stripe * data_disks + i;

	r_sector = (sector_t)chunk_number * sectors_per_chunk + chunk_offset;

	r_sector = chunk_number * sectors_per_chunk + chunk_offset;



	check = raid5_compute_sector(conf, r_sector,

				     previous, &dummy1, &sh2);