From: Nigel Croxon <ncroxon@redhat.com>
Date: Fri, 6 Sep 2019 09:21:33 -0400
Subject: raid5: don't increment read_errors on EILSEQ return
Git-commit: b76b4715eba0d0ed574f58918b29c1b2f0fa37a8
Patch-mainline: 5.4-rc1
References: bnc#1151927 5.3.4

While MD continues to count read errors returned by the lower layer.
If those errors are -EILSEQ, instead of -EIO, it should NOT increase
the read_errors count.

When RAID6 is set up on dm-integrity target that detects massive
corruption, the leg will be ejected from the array.  Even if the
issue is correctable with a sector re-write and the array has
necessary redundancy to correct it.

The leg is ejected because it runs up the rdev->read_errors beyond
conf->max_nr_stripes.  The return status in dm-drypt when there is
a data integrity error is -EILSEQ (BLK_STS_PROTECTION).

Signed-off-by: Nigel Croxon <ncroxon@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/md/raid5.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2526,7 +2526,8 @@ static void raid5_end_read_request(struc
 		int set_bad = 0;
 
 		clear_bit(R5_UPTODATE, &sh->dev[i].flags);
-		atomic_inc(&rdev->read_errors);
+		if (!(bi->bi_status == BLK_STS_PROTECTION))
+			atomic_inc(&rdev->read_errors);
 		if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
 			pr_warn_ratelimited(
 				"md/raid:%s: read error on replacement device (sector %llu on %s).\n",