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Subject: Re: [PATCH 4.4 63/97] md/raid10: skip spare disk as first disk
From: Ben Hutchings <ben.hutchings@codethink.co.uk>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org, Guoqing Jiang <gqjiang@suse.com>,
        NeilBrown <neilb@suse.com>, Shaohua Li <shli@fb.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Date: Tue, 03 Apr 2018 22:32:09 +0100
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         <20180323094201.150412201@linuxfoundation.org>
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On Fri, 2018-03-23 at 10:54 +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Shaohua Li <shli@fb.com>
> 
> 
> [ Upstream commit b506335e5d2b4ec687dde392a3bdbf7601778f1d ]
> 
> Commit 6f287ca(md/raid10: reset the 'first' at the end of loop) ignores
> a case in reshape, the first rdev could be a spare disk, which shouldn't
> be accounted as the first disk since it doesn't include the offset info.
> 
> Fix: 6f287ca(md/raid10: reset the 'first' at the end of loop)

But that commit hasn't been applied to 4.4-stable.  It probably should
be, since it fixes another instance of the problem in the run()
function.  Take care not to add the wrongly placed assignment
in raid10_start_reshape().

Ben.

> Cc: Guoqing Jiang <gqjiang@suse.com>
> Cc: NeilBrown <neilb@suse.com>
> Signed-off-by: Shaohua Li <shli@fb.com>
> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/md/raid10.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -4044,6 +4044,7 @@ static int raid10_start_reshape(struct m
>  				diff = 0;
>  			if (first || diff < min_offset_diff)
>  				min_offset_diff = diff;
> +			first = 0;
>  		}
>  	}
>  

-- 
Ben Hutchings
Software Developer, Codethink Ltd.