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>
This commit is contained in:
NeilBrown 2010-05-08 08:20:17 +10:00
parent 2dc40f8094
commit af3a2cd6b8
2 changed files with 3 additions and 3 deletions

View file

@ -418,7 +418,7 @@ static void raid1_end_write_request(struct bio *bio, int error)
*/
static int read_balance(conf_t *conf, r1bio_t *r1_bio)
{
const unsigned long this_sector = r1_bio->sector;
const sector_t this_sector = r1_bio->sector;
int new_disk = conf->last_used, disk = new_disk;
int wonly_disk = -1;
const int sectors = r1_bio->sectors;
@ -434,7 +434,7 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio)
retry:
if (conf->mddev->recovery_cp < MaxSector &&
(this_sector + sectors >= conf->next_resync)) {
/* Choose the first operation device, for consistancy */
/* Choose the first operational device, for consistancy */
new_disk = 0;
for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);

View file

@ -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;