Re: [PATCH 4/4] md: include events counters when kicking non-fresh device

[yu kuai]

Hi,

在 2026/7/19 22:44, Mykola Marzhan 写道:
> When analyze_sbs() kicks a member with a stale events counter, the
> warning names the device but not the divergence that caused the
> kick, so judging whether the kicked member is salvageable means
> running mdadm --examine on every member.  Print the member's on-disk
> events counter and the freshest events counter in the warning
> itself.

If user space tools can do this already, then user space tools should be
considered preferred.

>
> rdev->sb_events cannot be used here: it is only assigned when a
> superblock is written and still reads 0 during assemble.  Read the
> counter from the superblock page instead -- md_event() for 0.90
> metadata, the little-endian events field for 1.x.
>
> The legacy substring "kicking non-fresh %pg from array!" is
> unchanged, so existing log parsers continue to match.
>
> Assisted-by: Claude-Code:claude-opus-4-8
> Signed-off-by: Mykola Marzhan <mykola@xxxxxxxxxxx>
> ---
>   drivers/md/md.c | 25 +++++++++++++++++++++++--
>   1 file changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index d60ea7aaca3a..9ec87375a717 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -3934,8 +3934,29 @@ static int analyze_sbs(struct mddev *mddev)
>   		if (rdev != freshest) {
>   			if (super_types[mddev->major_version].
>   			    validate_super(mddev, freshest, rdev)) {
> -				pr_warn("md: kicking non-fresh %pg from array!\n",
> -					rdev->bdev);
> +				u64 rdev_events = 0;
> +
> +				/*
> +				 * rdev->sb_events is only assigned when
> +				 * writing a superblock and reads 0 during
> +				 * assemble; read events from the on-disk
> +				 * superblock instead.
> +				 */
> +				if (rdev->sb_page) {
> +					if (mddev->major_version == 1) {
> +						struct mdp_superblock_1 *sb =
> +							page_address(rdev->sb_page);
> +						rdev_events = le64_to_cpu(sb->events);
> +					} else if (mddev->major_version == 0) {
> +						mdp_super_t *sb =
> +							page_address(rdev->sb_page);
> +						rdev_events = md_event(sb);
> +					}
> +				}
> +				pr_warn("md: kicking non-fresh %pg from array! (events=%llu, freshest=%llu)\n",
> +					rdev->bdev,
> +					(unsigned long long)rdev_events,
> +					(unsigned long long)mddev->events);

And I don't like the above changes. If you really want such log, please add
it inside validate_super() methods.

>   				md_kick_rdev_from_array(rdev);
>   				continue;
>   			}

-- 
Thanks,
Kuai