Re: [PATCH v1] xfs: Fix rgcount/rgsize value reported in XFS_IOC_FSGEOMETRY ioctl

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

On Mon, Dec 08, 2025 at 08:46:11PM +0530, Nirjhar Roy (IBM) wrote:
> With mkfs.xfs -m dir=0 i.e, with XFS_SB_FEAT_INCOMPAT_METADIR
> disabled, number of realtime groups should be reported as 1 and
> the size of it should be equal to total number of realtime
> extents since this the entire realtime filesystem has only 1
> realtime group.

No.  This (pre-metadir realtime having one group encompassing the entire
rt volume) is an implementation detail, not a property of the filesystem
geometry.

Or put another way: a metadir rt filesystem with one rtgroup that covers
the entire rt device is different from a pre-metadir rt filesystem.
xfs_info should present that distinction to userspace, particularly
since xfs_scrub cares about that difference.

--D

> Signed-off-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
> ---
>  fs/xfs/libxfs/xfs_sb.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> index cdd16dd805d7..989553e7ec02 100644
> --- a/fs/xfs/libxfs/xfs_sb.c
> +++ b/fs/xfs/libxfs/xfs_sb.c
> @@ -875,7 +875,7 @@ __xfs_sb_from_disk(
>  	} else {
>  		to->sb_metadirino = NULLFSINO;
>  		to->sb_rgcount = 1;
> -		to->sb_rgextents = 0;
> +		to->sb_rgextents = to->sb_rextents;
>  	}
>  
>  	if (to->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_ZONED) {
> @@ -1586,10 +1586,8 @@ xfs_fs_geometry(
>  
>  	geo->version = XFS_FSOP_GEOM_VERSION_V5;
>  
> -	if (xfs_has_rtgroups(mp)) {
> -		geo->rgcount = sbp->sb_rgcount;
> -		geo->rgextents = sbp->sb_rgextents;
> -	}
> +	geo->rgcount = sbp->sb_rgcount;
> +	geo->rgextents = sbp->sb_rgextents;
>  	if (xfs_has_zoned(mp)) {
>  		geo->rtstart = sbp->sb_rtstart;
>  		geo->rtreserved = sbp->sb_rtreserved;
> -- 
> 2.43.5
> 
>