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Message-ID: <503E4E5F.5060003@kernel.dk>
Date: Wed, 29 Aug 2012 10:16:15 -0700
From: Jens Axboe <axboe@kernel.dk>
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To: "Martin K. Petersen" <martin.petersen@oracle.com>
CC: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] block: Fix bad range check in bio_sector_offset
References: <yq1a9xesxll.fsf@sermon.lab.mkp.net>
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On 2012-08-28 11:03, Martin K. Petersen wrote:
> 
> DM would occasionally end up splitting data integrity-enabled requests
> incorrectly. The culprit was a bad range check in bio_sector_offset.
> 
> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
> Cc: <stable@vger.kernel.org>
> 
> diff --git a/fs/bio.c b/fs/bio.c
> index 9bfade8..b9a6744 100644
> --- a/fs/bio.c
> +++ b/fs/bio.c
> @@ -1552,8 +1552,8 @@ sector_t bio_sector_offset(struct bio *bio, unsigned short index,
>  	sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
>  	sectors = 0;
>  
> -	if (index >= bio->bi_idx)
> -		index = bio->bi_vcnt - 1;
> +	if (index > bio->bi_vcnt)
> +		return 0;
>  
>  	__bio_for_each_segment(bv, bio, i, 0) {
>  		if (i == index) {

Good catch, merged.

-- 
Jens Axboe