[PATCH v2 3/3] md/raid1: keep holding the barrier in handle_read_error()

[Xueshi Hu <xueshi.hu@smartx.com>]

From: Xueshi Hu <xueshi.hu@smartx.com>

Raid reshape changes the r1conf::raid_disks and mempool. Keep holding the
barrier in handle_read_error() to avoid raid reshape.

Signed-off-by: Xueshi Hu <xueshi.hu@smartx.com>
---
 drivers/md/raid1.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 6c54786067b4..43a9c095f94d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1240,20 +1240,20 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
 		rcu_read_unlock();
 	}
 
-	/*
-	 * Still need barrier for READ in case that whole
-	 * array is frozen.
-	 */
-	if (!wait_read_barrier(conf, bio->bi_iter.bi_sector,
-				bio->bi_opf & REQ_NOWAIT)) {
-		bio_wouldblock_error(bio);
-		return;
-	}
-
-	if (!r1_bio)
+	if (!r1_bio) {
+		/*
+		 * Still need barrier for READ in case that whole
+		 * array is frozen.
+		 */
+		if (!wait_read_barrier(conf, bio->bi_iter.bi_sector,
+					bio->bi_opf & REQ_NOWAIT)) {
+			bio_wouldblock_error(bio);
+			return;
+		}
 		r1_bio = alloc_r1bio(mddev, bio);
-	else
+	} else
 		init_r1bio(r1_bio, mddev, bio);
+
 	r1_bio->sectors = max_read_sectors;
 
 	/*
@@ -2527,7 +2527,6 @@ static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio)
 	}
 
 	rdev_dec_pending(rdev, conf->mddev);
-	allow_barrier(conf, r1_bio->sector);
 	bio = r1_bio->master_bio;
 
 	/* Reuse the old r1_bio so that the IO_BLOCKED settings are preserved */
-- 
2.40.1