Thread (2 messages) 2 messages, 2 authors, 2017-11-17

Re: [PATCH] md/raid5: correct degraded calculation in raid5_error

From: Shaohua Li <shli@kernel.org>
Date: 2017-11-17 18:44:04

On Fri, Nov 17, 2017 at 10:57:44AM +0800, bingjingc wrote:
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 <redacted>
Reviewed-by: Alex Wu <redacted>
Signed-off-by: BingJing Chang <redacted>
Applied, thanks!
quoted hunk ↗ jump to hunk
---
 drivers/md/raid5.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 31dc25e..98ce427 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -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
--
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