Merge tag 'md-6.11-20240815' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into block-6.11

Pull MD fix from Song:

"This patch fixes a potential data corruption in degraded raid0 array
 with slow (WriteMostly) drives. This issue was introduced in upstream
 6.9 kernel."

* tag 'md-6.11-20240815' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md/raid1: Fix data corruption for degraded array with slow disk

Author: axboe

drivers/md/raid1.c

@@ -617,6 +617,12 @@ static int choose_first_rdev(struct r1conf *conf, struct r1bio *r1_bio,
 	return -1;
 }
 
+static bool rdev_in_recovery(struct md_rdev *rdev, struct r1bio *r1_bio)
+{
+	return !test_bit(In_sync, &rdev->flags) &&
+	       rdev->recovery_offset < r1_bio->sector + r1_bio->sectors;
+}
+
 static int choose_bb_rdev(struct r1conf *conf, struct r1bio *r1_bio,
 			  int *max_sectors)
 {
@@ -635,6 +641,7 @@ static int choose_bb_rdev(struct r1conf *conf, struct r1bio *r1_bio,
 
 		rdev = conf->mirrors[disk].rdev;
 		if (!rdev || test_bit(Faulty, &rdev->flags) ||
+		    rdev_in_recovery(rdev, r1_bio) ||
 		    test_bit(WriteMostly, &rdev->flags))
 			continue;
 
@@ -673,7 +680,8 @@ static int choose_slow_rdev(struct r1conf *conf, struct r1bio *r1_bio,
 
 		rdev = conf->mirrors[disk].rdev;
 		if (!rdev || test_bit(Faulty, &rdev->flags) ||
-		    !test_bit(WriteMostly, &rdev->flags))
+		    !test_bit(WriteMostly, &rdev->flags) ||
+		    rdev_in_recovery(rdev, r1_bio))
 			continue;
 
 		/* there are no bad blocks, we can use this disk */
@@ -733,9 +741,7 @@ static bool rdev_readable(struct md_rdev *rdev, struct r1bio *r1_bio)
 	if (!rdev || test_bit(Faulty, &rdev->flags))
 		return false;
 
-	/* still in recovery */
-	if (!test_bit(In_sync, &rdev->flags) &&
-	    rdev->recovery_offset < r1_bio->sector + r1_bio->sectors)
+	if (rdev_in_recovery(rdev, r1_bio))
 		return false;
 
 	/* don't read from slow disk unless have to */