linux-kernel - Re: [PATCH v2 2/7] md: don't wait faulty rdev in md_wait_for_blocked

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Message-ID: <7e069314-4f6d-d291-8650-a37e95268d9b@huaweicloud.com>
Date: Wed, 30 Oct 2024 09:22:46 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: Yu Kuai <yukuai1@...weicloud.com>, song@...nel.org,
 mariusz.tkaczyk@...el.com
Cc: linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org,
 yi.zhang@...wei.com, yangerkun@...wei.com, "yukuai (C)" <yukuai3@...wei.com>
Subject: Re: [PATCH v2 2/7] md: don't wait faulty rdev in
 md_wait_for_blocked_rdev()

Hi,

在 2024/10/11 9:16, Yu Kuai 写道:
> From: Yu Kuai <yukuai3@...wei.com>
> 
> md_wait_for_blocked_rdev() is called for write IO while rdev is
> blocked, howerver, rdev can be faulty after choosing this rdev to write,
> and faulty rdev should never be accessed anymore, hence there is no point
> to wait for faulty rdev to be unblocked.
> 
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
> ---
>   drivers/md/md.c | 4 +---
>   1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 179ee4afe937..37d1469bfc82 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -9762,9 +9762,7 @@ EXPORT_SYMBOL(md_reap_sync_thread);
>   void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev)
>   {
>   	sysfs_notify_dirent_safe(rdev->sysfs_state);
> -	wait_event_timeout(rdev->blocked_wait,
> -			   !test_bit(Blocked, &rdev->flags) &&
> -			   !test_bit(BlockedBadBlocks, &rdev->flags),
> +	wait_event_timeout(rdev->blocked_wait, rdev_blocked(rdev),

Just found that there is a stupid mistake that I should use:

!rdev_blocked(rdev)

Tests can't find this mistake because wait_event_timeout() is used,
and caller will break out if rdev is unblocked.

Song, since this is still is md-6.13. Do you want to to send a fix, or
update this version?

Thanks,
Kuai

>   			   msecs_to_jiffies(5000));
>   	rdev_dec_pending(rdev, mddev);
>   }
>