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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Xiao Ni <xni@redhat.com>,
        Song Liu <songliubraving@fb.com>
Subject: [PATCH 4.14 33/34] Its wrong to add len to sector_nr in raid10 reshape twice
Date:   Mon, 18 Mar 2019 10:25:57 +0100
Message-Id: <20190318084149.634296540@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Xiao Ni <xni@redhat.com>

commit b761dcf1217760a42f7897c31dcb649f59b2333e upstream.

In reshape_request it already adds len to sector_nr already. It's wrong to add len to
sector_nr again after adding pages to bio. If there is bad block it can't copy one chunk
at a time, it needs to goto read_more. Now the sector_nr is wrong. It can cause data
corruption.

Cc: stable@vger.kernel.org # v3.16+
Signed-off-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/raid10.c |    1 -
 1 file changed, 1 deletion(-)

--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4495,7 +4495,6 @@ read_more:
 	atomic_inc(&r10_bio->remaining);
 	read_bio->bi_next = NULL;
 	generic_make_request(read_bio);
-	sector_nr += nr_sectors;
 	sectors_done += nr_sectors;
 	if (sector_nr <= last)
 		goto read_more;