Commit aff69d89 authored Nov 17, 2017 by bingjingc Committed by Shaohua Li Dec 01, 2017

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 <roychung@synology.com>
Reviewed-by: Alex Wu <alexwu@synology.com>
Signed-off-by: BingJing Chang <bingjingc@synology.com>
Signed-off-by: Shaohua Li <shli@fb.com>

parent a0651c7f

drivers/md/raid5.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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"

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