Re: [PATCH V2] xfsprogs: xfs_fsr: Verify bulkstat version information in qsort's cmp()

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Jan 28, 2021 at 10:50:58AM +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>
> ---

Looks good to me,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> V1 -> V2:
>    1. Include XFS_BULKSTAT_VERSION_V1 as a possible bulkstat version
>       number. 
>    2. Fix coding style issue.
>    
>  fsr/xfs_fsr.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/fsr/xfs_fsr.c b/fsr/xfs_fsr.c
> index b885395e..6cf8bfb7 100644
> --- a/fsr/xfs_fsr.c
> +++ b/fsr/xfs_fsr.c
> @@ -582,8 +582,15 @@ 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_V1 &&
> +		bs2->bs_version == XFS_BULKSTAT_VERSION_V1) ||
> +		(bs1->bs_version == XFS_BULKSTAT_VERSION_V5 &&
> +		bs2->bs_version == XFS_BULKSTAT_VERSION_V5));
> +
> +	return (bs2->bs_extents - bs1->bs_extents);
>  }
>  
>  /*
> -- 
> 2.29.2
>