Re: [PATCH] xfsprogs: xfs_fsr: Verify bulkstat version information in qsort's cmp()

From: "Darrick J. Wong" <djwong@kernel.org>
To: Chandan Babu R <chandanrlinux@gmail.com>
Cc: linux-xfs@vger.kernel.org, sandeen@sandeen.net
Subject: Re: [PATCH] xfsprogs: xfs_fsr: Verify bulkstat version information in qsort's cmp()
Date: Wed, 27 Jan 2021 08:34:37 -0800	[thread overview]
Message-ID: <20210127163437.GH7698@magnolia> (raw)
In-Reply-To: <20210127092405.2841857-1-chandanrlinux@gmail.com>

On Wed, Jan 27, 2021 at 02:54:05PM +0530, Chandan Babu R wrote:
> This commit introduces a check to verify that correct bulkstat structures are
> being processed by qsort's cmp() function.
> 
> Suggested-by: Darrick J. Wong <djwong@kernel.org>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
> ---
>  fsr/xfs_fsr.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/fsr/xfs_fsr.c b/fsr/xfs_fsr.c
> index b885395e..de7e8190 100644
> --- a/fsr/xfs_fsr.c
> +++ b/fsr/xfs_fsr.c
> @@ -582,8 +582,13 @@ fsrall_cleanup(int timeout)
>  static int
>  cmp(const void *s1, const void *s2)
>  {
> -	return( ((struct xfs_bulkstat *)s2)->bs_extents -
> -	        ((struct xfs_bulkstat *)s1)->bs_extents);
> +	const struct xfs_bulkstat	*bs1 = s1;
> +	const struct xfs_bulkstat	*bs2 = s2;
> +
> +	ASSERT(bs1->bs_version == XFS_BULKSTAT_VERSION_V5
> +		&& bs2->bs_version == XFS_BULKSTAT_VERSION_V5);

Stylistic nit: the '&&' goes on the previous line; and
bs_version can also be XFS_BULKSTAT_VERSION_V1.

--D

> +
> +	return (bs2->bs_extents - bs1->bs_extents);
>  }
>  
>  /*
> -- 
> 2.29.2
> 