Re: [PATCH v3] xfs: define a flags field for the AG geometry ioctl structure

[Dave Chinner <david@fromorbit.com>]

On Tue, Sep 03, 2019 at 04:05:37PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Define a flags field for the AG geometry ioctl structure.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> v3: define ag_flags as an in/out field and check required zeroness
> ---
>  fs/xfs/libxfs/xfs_fs.h |    2 +-
>  fs/xfs/xfs_ioctl.c     |    4 ++++
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
> index 52d03a3a02a4..39dd2b908106 100644
> --- a/fs/xfs/libxfs/xfs_fs.h
> +++ b/fs/xfs/libxfs/xfs_fs.h
> @@ -287,7 +287,7 @@ struct xfs_ag_geometry {
>  	uint32_t	ag_ifree;	/* o: inodes free */
>  	uint32_t	ag_sick;	/* o: sick things in ag */
>  	uint32_t	ag_checked;	/* o: checked metadata in ag */
> -	uint32_t	ag_reserved32;	/* o: zero */
> +	uint32_t	ag_flags;	/* i/o: flags for this ag */
>  	uint64_t	ag_reserved[12];/* o: zero */
>  };
>  #define XFS_AG_GEOM_SICK_SB	(1 << 0)  /* superblock */
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 9a6823e29661..c93501f42675 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1038,6 +1038,10 @@ xfs_ioc_ag_geometry(
>  
>  	if (copy_from_user(&ageo, arg, sizeof(ageo)))
>  		return -EFAULT;
> +	if (ageo.ag_flags)
> +		return -EINVAL;
> +	if (memchr_inv(&ageo.ag_reserved, 0, sizeof(ageo.ag_reserved)))
> +		return -EINVAL;

Looks good. All that should be zero until we start using them. :)

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com