GIT: unionfs2-2.6.27.y: md: Fix read balancing in RAID1 and RAID10 on drives > 2TB

[Erez Zadok]

commit f2a41e6807357c237ec2bbd61e79cb1558e48b8a
Author: NeilBrown <neilb at suse.de>
Date:   Sat May 8 08:20:17 2010 +1000

    md: Fix read balancing in RAID1 and RAID10 on drives > 2TB
    
    commit af3a2cd6b8a479345786e7fe5e199ad2f6240e56 upstream.
    
    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 at quo.to>
    Signed-off-by: NeilBrown <neilb at suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index acbbe5d..4b78069 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -413,7 +413,7 @@ 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;
@@ -429,7 +429,7 @@ 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);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index b08dd95..dbf51e9 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -490,7 +490,7 @@ 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;