4.14-stable review patch. If anyone has any objections, please let me know.
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From: bingjingc bingjingc@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 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 Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@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"