From 1cdd1257949c85c5ddff8313fe3b1e39c5bee8b8 Mon Sep 17 00:00:00 2001
From: Guoqing Jiang <gqjiang@suse.com>
Date: Tue, 13 Jun 2017 11:16:08 +0800
Subject: [PATCH] md/raid10: fix FailFast test for wrong device
Git-commit: 1cdd1257949c85c5ddff8313fe3b1e39c5bee8b8
Patch-mainline: v4.13-rc1
References: fate#322738,fate#322919,fate#322950,fate#323773

We need to test FailFast flag for replacement device here
since the set up for writing is for the replacement, so we
need fix it like:

- if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
+ if (test_bit(FailFast, &conf->mirrors[d].replacement->flags))

Since commit f90145f317ef ("md/raid10: add rcu protection
to rdev access in raid10_sync_request.") had added the rcu
protection for the part, so let's extend the range protected
by rcu and use rdev directly.

Fixes: 1919cbb ("md/raid10: add failfast handling for writes.")
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/md/raid10.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 52acffa7a06a..305b0db5a293 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -3295,7 +3295,7 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 			biolist = bio;
 			bio->bi_end_io = end_sync_read;
 			bio_set_op_attrs(bio, REQ_OP_READ, 0);
-			if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
+			if (test_bit(FailFast, &rdev->flags))
 				bio->bi_opf |= MD_FAILFAST;
 			bio->bi_iter.bi_sector = sector + rdev->data_offset;
 			bio->bi_bdev = rdev->bdev;
@@ -3307,7 +3307,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 				continue;
 			}
 			atomic_inc(&rdev->nr_pending);
-			rcu_read_unlock();
 
 			/* Need to set up for writing to the replacement */
 			bio = r10_bio->devs[i].repl_bio;
@@ -3318,11 +3317,12 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 			biolist = bio;
 			bio->bi_end_io = end_sync_write;
 			bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
-			if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
+			if (test_bit(FailFast, &rdev->flags))
 				bio->bi_opf |= MD_FAILFAST;
 			bio->bi_iter.bi_sector = sector + rdev->data_offset;
 			bio->bi_bdev = rdev->bdev;
 			count++;
+			rcu_read_unlock();
 		}
 
 		if (count < 2) {
-- 
2.13.1