It's wrong to add len to sector_nr in raid10 reshape twice

BugLink: https://bugs.launchpad.net/bugs/1837952
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>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 4d38a23b5a791e88974106d0c87488bff210f1c2..b8f7a456c8cb4ae532f4aed546b166673274afa5 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4621,7 +4621,6 @@ 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;