4.14-stable review patch.  If anyone has any objections, please let me know.


From: bingjingc <bingji...@synology.com>

[ Upstream commit aff69d89bdebc39235cddb4445371eb979b49685 ]

When disk failure occurs on new disks for reshape, mddev->degraded
is not calculated correctly. Faulty bit of the failure device is not
set before raid5_calc_degraded(conf).

mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/loop[012]
mdadm /dev/md0 -a /dev/loop3
mdadm /dev/md0 --grow -n4
mdadm /dev/md0 -f /dev/loop3 # simulating disk failure

cat /sys/block/md0/md/degraded # it outputs 0, but it should be 1.

However, mdadm -D /dev/md0 will show that it is degraded. It's a bug.
It can be fixed by moving the resources raid5_calc_degraded() depends
on before it.

Reported-by: Roy Chung <roych...@synology.com>
Reviewed-by: Alex Wu <ale...@synology.com>
Signed-off-by: BingJing Chang <bingji...@synology.com>
Signed-off-by: Shaohua Li <s...@fb.com>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
 drivers/md/raid5.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2678,13 +2678,13 @@ static void raid5_error(struct mddev *md
        pr_debug("raid456: error called\n");
        spin_lock_irqsave(&conf->device_lock, flags);
+       set_bit(Faulty, &rdev->flags);
        clear_bit(In_sync, &rdev->flags);
        mddev->degraded = raid5_calc_degraded(conf);
        spin_unlock_irqrestore(&conf->device_lock, flags);
        set_bit(MD_RECOVERY_INTR, &mddev->recovery);
        set_bit(Blocked, &rdev->flags);
-       set_bit(Faulty, &rdev->flags);
        set_mask_bits(&mddev->sb_flags, 0,
                      BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
        pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"

Reply via email to