md: Fix read balancing in RAID1 and RAID10 on drives > 2TB

read_balance uses a "unsigned long" for a sector number which
will get truncated beyond 2TB.
This will cause read-balancing to be non-optimal, and can cause
data to be read from the 'wrong' branch during a resync.  This has a
very small chance of returning wrong data.

Reported-by: Jordan Russell <jr-list-2010@quo.to>
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e0742c439484..a1f5fd2d69ce 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -495,7 +495,7 @@ static int raid10_mergeable_bvec(struct request_queue *q,
  */
 static int read_balance(conf_t *conf, r10bio_t *r10_bio)
 {
-        const unsigned long this_sector = r10_bio->sector;
+        const sector_t this_sector = r10_bio->sector;
         int disk, slot, nslot;
         const int sectors = r10_bio->sectors;
         sector_t new_distance, current_distance;