Re: [PATCH 3/9] xfs: add a xfs_rtblock_payload helper

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

On Thu, Sep 24, 2026 at 11:57:04AM +0200, Christoph Hellwig wrote:
> Add a helper to calculate the rtblock payload start with or without the
> self-describing metadata header.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Nice refactoring!
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/xfs/libxfs/xfs_rtbitmap.c |  9 ++-------
>  fs/xfs/libxfs/xfs_rtbitmap.h | 27 ++++++++++++---------------
>  2 files changed, 14 insertions(+), 22 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c
> index 5cadde81b5da..01536f4fb386 100644
> --- a/fs/xfs/libxfs/xfs_rtbitmap.c
> +++ b/fs/xfs/libxfs/xfs_rtbitmap.c
> @@ -1411,7 +1411,6 @@ xfs_rtfile_initialize_block(
>  	struct xfs_inode	*ip = rtg->rtg_inodes[type];
>  	struct xfs_trans	*tp;
>  	struct xfs_buf		*bp;
> -	void			*bufdata;
>  	const size_t		copylen = mp->m_blockwsize << XFS_WORDLOG;
>  	int			error;
>  
> @@ -1427,16 +1426,12 @@ xfs_rtfile_initialize_block(
>  		xfs_trans_cancel(tp);
>  		return error;
>  	}
> -	bufdata = bp->b_addr;
>  
>  	xfs_rtfile_initialize_buf(rtg, type, bp, tp);
> -
> -	if (xfs_has_rtgroups(mp))
> -		bufdata += sizeof(struct xfs_rtbuf_blkinfo);
>  	if (data)
> -		memcpy(bufdata, data, copylen);
> +		memcpy(xfs_rtblock_payload(bp), data, copylen);
>  	else
> -		memset(bufdata, 0, copylen);
> +		memset(xfs_rtblock_payload(bp), 0, copylen);
>  	xfs_trans_log_buf(tp, bp, 0, mp->m_sb.sb_blocksize - 1);
>  	return xfs_trans_commit(tp);
>  }
> diff --git a/fs/xfs/libxfs/xfs_rtbitmap.h b/fs/xfs/libxfs/xfs_rtbitmap.h
> index 4a87e1fd3e99..750d74fbf4ed 100644
> --- a/fs/xfs/libxfs/xfs_rtbitmap.h
> +++ b/fs/xfs/libxfs/xfs_rtbitmap.h
> @@ -20,6 +20,16 @@ struct xfs_rtalloc_args {
>  	xfs_fileoff_t		sumoff;	/* summary block number */
>  };
>  
> +/* Return the payload of the buffer after the optional header. */
> +static inline void *
> +xfs_rtblock_payload(
> +	struct xfs_buf		*bp)
> +{
> +	if (!xfs_has_rtgroups(bp->b_mount))
> +		return bp->b_addr;
> +	return bp->b_addr + sizeof(struct xfs_rtbuf_blkinfo);
> +}
> +
>  static inline xfs_rtblock_t
>  xfs_rtx_to_rtb(
>  	struct xfs_rtgroup	*rtg,
> @@ -221,14 +231,7 @@ xfs_rbmblock_wordptr(
>  	struct xfs_rtalloc_args	*args,
>  	unsigned int		index)
>  {
> -	struct xfs_mount	*mp = args->mp;
> -	union xfs_rtword_raw	*words;
> -	struct xfs_rtbuf_blkinfo *hdr = args->rbmbp->b_addr;
> -
> -	if (xfs_has_rtgroups(mp))
> -		words = (union xfs_rtword_raw *)(hdr + 1);
> -	else
> -		words = args->rbmbp->b_addr;
> +	union xfs_rtword_raw	*words = xfs_rtblock_payload(args->rbmbp);
>  
>  	return words + index;
>  }
> @@ -312,13 +315,7 @@ xfs_rsumblock_infoptr(
>  	struct xfs_rtalloc_args	*args,
>  	unsigned int		index)
>  {
> -	union xfs_suminfo_raw	*info;
> -	struct xfs_rtbuf_blkinfo *hdr = args->sumbp->b_addr;
> -
> -	if (xfs_has_rtgroups(args->mp))
> -		info = (union xfs_suminfo_raw *)(hdr + 1);
> -	else
> -		info = args->sumbp->b_addr;
> +	union xfs_suminfo_raw	*info = xfs_rtblock_payload(args->sumbp);
>  
>  	return info + index;
>  }
> -- 
> 2.53.0
> 
>