Re: [PATCH V4 RESEND 3/7] xfs: xfs_attr_calc_size: Calculate Bmbt blks only once

[Brian Foster <bfoster@redhat.com>]

On Mon, Feb 24, 2020 at 09:30:40AM +0530, Chandan Rajendra wrote:
> The number of Bmbt blocks that is required can be calculated only once by
> passing the sum of total number of dabtree blocks and remote blocks to
> XFS_NEXTENTADD_SPACE_RES() macro.
> 
> Signed-off-by: Chandan Rajendra <chandanrlinux@gmail.com>
> ---

According to the cover letter this is fixing a reservation calculation
issue, though the commit log kind of gives the impression it's a
refactor. Can you elaborate on what this fixes in the commit log?

Brian

>  fs/xfs/libxfs/xfs_attr.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 942ba552e0bdd..a708b142f69b6 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -154,12 +154,10 @@ xfs_attr_calc_size(
>  	size = xfs_attr_leaf_newentsize(args->geo, args->namelen,
>  			args->valuelen, local);
>  	total_dablks = XFS_DAENTER_BLOCKS(mp, XFS_ATTR_FORK);
> -	bmbt_blks = XFS_DAENTER_BMAPS(mp, XFS_ATTR_FORK);
>  	if (*local) {
>  		if (size > (args->geo->blksize / 2)) {
>  			/* Double split possible */
>  			total_dablks *= 2;
> -			bmbt_blks *= 2;
>  		}
>  		rmt_blks = 0;
>  	} else {
> @@ -168,10 +166,11 @@ xfs_attr_calc_size(
>  		 * make room for the attribute value itself.
>  		 */
>  		rmt_blks = xfs_attr3_rmt_blocks(mp, args->valuelen);
> -		bmbt_blks += XFS_NEXTENTADD_SPACE_RES(mp, rmt_blks,
> -				XFS_ATTR_FORK);
>  	}
>  
> +	bmbt_blks = XFS_NEXTENTADD_SPACE_RES(mp, total_dablks + rmt_blks,
> +			XFS_ATTR_FORK);
> +
>  	return total_dablks + rmt_blks + bmbt_blks;
>  }
>  
> -- 
> 2.19.1
>