Re: [PATCH] mkfs: use a default sector size that is also suitable for the rtdev

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

On Mon, Jan 27, 2025 at 02:54:03PM +0100, Christoph Hellwig wrote:
> When creating a filesytem where the data device has a sector size
> smalle than that of the RT device without further options, mkfs
> currently fails with:
> 
> mkfs.xfs: error - cannot set blocksize 512 on block device $RTDEV: Invalid argument
> 
> This is because XFS sets the sector size based on logical block size
> of the data device, but not that of the RT device.  Change the code
> so that is uses the larger of the two values.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

That makes sense to me.
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  mkfs/xfs_mkfs.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> index 6cc7e6439ca1..0627af81da37 100644
> --- a/mkfs/xfs_mkfs.c
> +++ b/mkfs/xfs_mkfs.c
> @@ -2368,7 +2368,9 @@ validate_sectorsize(
>  		 * advertised sector size of the device.  We use the physical
>  		 * sector size unless the requested block size is smaller
>  		 * than that, then we can use logical, but warn about the
> -		 * inefficiency.
> +		 * inefficiency.  If the file system has a RT device, the
> +		 * sectorsize needs to be the maximum of the data and RT
> +		 * device.
>  		 *
>  		 * Some architectures have a page size > XFS_MAX_SECTORSIZE.
>  		 * In that case, a ramdisk or persistent memory device may
> @@ -2378,8 +2380,18 @@ validate_sectorsize(
>  			ft->data.physical_sector_size =
>  				ft->data.logical_sector_size;
>  		}
> -
>  		cfg->sectorsize = ft->data.physical_sector_size;
> +
> +		if (cli->xi->rt.name) {
> +			if (ft->rt.physical_sector_size > XFS_MAX_SECTORSIZE) {
> +				ft->rt.physical_sector_size =
> +					ft->rt.logical_sector_size;
> +			}
> +
> +			if (cfg->sectorsize < ft->rt.physical_sector_size)
> +				cfg->sectorsize = ft->rt.physical_sector_size;
> +		}
> +
>  		if (cfg->blocksize < cfg->sectorsize &&
>  		    cfg->blocksize >= ft->data.logical_sector_size) {
>  			fprintf(stderr,
> -- 
> 2.45.2
> 
>