Re: [PATCH 3/3 v2] md: unblock array if bad blocks have been acknowledged

[Shaohua Li <shli@kernel.org>]

On Tue, Oct 18, 2016 at 04:10:24PM +0200, Tomasz Majchrzak wrote:
> Once external metadata handler acknowledges all bad blocks (by writing
> to rdev 'bad_blocks' sysfs file), it requests to unblock the array.
> Check if all bad blocks are actually acknowledged as there might be a
> race if new bad blocks are notified at the same time. If all bad blocks
> are acknowledged, just unblock the array and continue. If not, ignore
> the request to unblock (do not fail an array). External metadata handler
> is expected to either process remaining bad blocks and try to unblock
> again or remove bad block support for a disk (which will cause disk to
> fail as in no-support case).
> 
> Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
> Reviewed-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
> ---
>  drivers/md/md.c | 24 +++++++++++++++++-------
>  1 file changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index cc05236..ce585b7 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -2612,19 +2612,29 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len)
>  		set_bit(Blocked, &rdev->flags);
>  		err = 0;
>  	} else if (cmd_match(buf, "-blocked")) {
> -		if (!test_bit(Faulty, &rdev->flags) &&
> +		int unblock = 1;
> +		int acked = !rdev->badblocks.unacked_exist;
> +
> +		if ((test_bit(ExternalBbl, &rdev->flags) &&
> +		     rdev->badblocks.changed))
> +			acked = check_if_badblocks_acked(&rdev->badblocks);
> +
> +		if (test_bit(ExternalBbl, &rdev->flags) && !acked) {
> +			unblock = 0;
> +		} else if (!test_bit(Faulty, &rdev->flags) &&

I missed one thing in last review. writing to bad_blocks sysfs file already
clears the BlockedBadBlocks bit and wakeup the thread sleeping at blocked_wait,
so the array can continue. Why do we need to fix state_store here?

Thanks,
Shaohua