From mboxrd@z Thu Jan  1 00:00:00 1970
From: Shaohua Li <shli@kernel.org>
Subject: Re: [md PATCH 01/18] md: disconnect device from personality before
 trying to remove it.
Date: Fri, 3 Jun 2016 15:31:30 -0700
Message-ID: <20160603223130.GB1898@kernel.org>
References: <20160602061319.2939.72280.stgit@noble>
 <20160602061952.2939.77544.stgit@noble>
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Sender: linux-raid-owner@vger.kernel.org
To: NeilBrown <neilb@suse.com>
Cc: linux-raid@vger.kernel.org
List-Id: linux-raid.ids

On Thu, Jun 02, 2016 at 04:19:52PM +1000, Neil Brown wrote:
> When the HOT_REMOVE_DISK ioctl is used to remove a device, we
> call remove_and_add_spares() which will remove it from the personality
> if possible.  This improves the chances that the removal will succeed.
> 
> When writing "remove" to dev-XX/state, we don't.  So that can fail more easily.
> 
> So add the remove_and_add_spares() into "remove" handling.
> 
> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
>  drivers/md/md.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 866825f10b4c..2d26099e1160 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -2596,6 +2596,8 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len)
>  		else
>  			err = -EBUSY;
>  	} else if (cmd_match(buf, "remove")) {
> +		clear_bit(Blocked, &rdev->flags);
> +		remove_and_add_spares(rdev->mddev, rdev);
>  		if (rdev->raid_disk >= 0)
>  			err = -EBUSY;
>  		else {

Do we need wakeup rdev->blocked_wait here? I noticed some times we do the
wakeup but sometimes we not. This makes me worry about
md_wait_for_blocked_rdev. Will timeout cause anything bad?

Thanks,
Shaohua