md/raid5: correct degraded calculation in raid5_error

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 <[email protected]>

Reviewed-by Alex Wu <[email protected]>

Signed-off-by BingJing Chang <[email protected]>

---
 drivers/md/raid5.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/md/raid5.c +1 -1

index 31dc25e..98ce427 100644
@@ -2677,13 +2677,13 @@ static void raid5_error(struct mddev *mddev, struct
 md_rdev *rdev)
 	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"
--
2.7.4
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html