[PATCH v2] xfs: overflow in xfs_iomap_eof_align_last_fsb

[Brian Foster]

On Mon, Dec 01, 2014 at 05:45:28PM -0500, Peter Watkins wrote:
> If extsize is set and new_last_fsb is larger than 32 bits, the
> roundup to extsize will overflow the align variable. Instead,
> combine alignments by rounding stripe size up to extsize.
> 
> Signed-off-by: Peter Watkins <treestem at gmail.com>
> Reviewed-by: Nathaniel W. Turner <nate at houseofnate.net>
> ---

Looks fine to me:

Reviewed-by: Brian Foster <bfoster at redhat.com>

>  fs/xfs/xfs_iomap.c |   13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index afcf3c9..3fad071 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -52,7 +52,6 @@ xfs_iomap_eof_align_last_fsb(
>  	xfs_extlen_t	extsize,
>  	xfs_fileoff_t	*last_fsb)
>  {
> -	xfs_fileoff_t	new_last_fsb = 0;
>  	xfs_extlen_t	align = 0;
>  	int		eof, error;
>  
> @@ -70,8 +69,8 @@ xfs_iomap_eof_align_last_fsb(
>  		else if (mp->m_dalign)
>  			align = mp->m_dalign;
>  
> -		if (align && XFS_ISIZE(ip) >= XFS_FSB_TO_B(mp, align))
> -			new_last_fsb = roundup_64(*last_fsb, align);
> +		if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
> +			align = 0;
>  	}
>  
>  	/*
> @@ -79,14 +78,14 @@ xfs_iomap_eof_align_last_fsb(
>  	 * (when file on a real-time subvolume or has di_extsize hint).
>  	 */
>  	if (extsize) {
> -		if (new_last_fsb)
> -			align = roundup_64(new_last_fsb, extsize);
> +		if (align)
> +			align = roundup_64(align, extsize);
>  		else
>  			align = extsize;
> -		new_last_fsb = roundup_64(*last_fsb, align);
>  	}
>  
> -	if (new_last_fsb) {
> +	if (align) {
> +		xfs_fileoff_t	new_last_fsb = roundup_64(*last_fsb, align);
>  		error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
>  		if (error)
>  			return error;
> -- 
> 1.7.9.5
> 
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