Re: [PATCH 38/43] xfs: add a max_open_zones mount option

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

On Thu, Feb 06, 2025 at 07:44:54AM +0100, Christoph Hellwig wrote:
> Allow limiting the number of open zones used below that exported by the
> device.  This is required to tune the number of write streams when zoned
> RT devices are used on conventional devices, and can be useful on zoned
> devices that support a very large number of open zones.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Seems pretty straightforward to me...
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

>  fs/xfs/xfs_super.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index ceb1a855453e..b59d7349dbd2 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -110,7 +110,7 @@ enum {
>  	Opt_filestreams, Opt_quota, Opt_noquota, Opt_usrquota, Opt_grpquota,
>  	Opt_prjquota, Opt_uquota, Opt_gquota, Opt_pquota,
>  	Opt_uqnoenforce, Opt_gqnoenforce, Opt_pqnoenforce, Opt_qnoenforce,
> -	Opt_discard, Opt_nodiscard, Opt_dax, Opt_dax_enum,
> +	Opt_discard, Opt_nodiscard, Opt_dax, Opt_dax_enum, Opt_max_open_zones,
>  };
>  
>  static const struct fs_parameter_spec xfs_fs_parameters[] = {
> @@ -155,6 +155,7 @@ static const struct fs_parameter_spec xfs_fs_parameters[] = {
>  	fsparam_flag("nodiscard",	Opt_nodiscard),
>  	fsparam_flag("dax",		Opt_dax),
>  	fsparam_enum("dax",		Opt_dax_enum, dax_param_enums),
> +	fsparam_u32("max_open_zones",	Opt_max_open_zones),
>  	{}
>  };
>  
> @@ -234,6 +235,9 @@ xfs_fs_show_options(
>  	if (!(mp->m_qflags & XFS_ALL_QUOTA_ACCT))
>  		seq_puts(m, ",noquota");
>  
> +	if (mp->m_max_open_zones)
> +		seq_printf(m, ",max_open_zones=%u", mp->m_max_open_zones);
> +
>  	return 0;
>  }
>  
> @@ -1081,6 +1085,14 @@ xfs_finish_flags(
>  		return -EINVAL;
>  	}
>  
> +	if (!xfs_has_zoned(mp)) {
> +		if (mp->m_max_open_zones) {
> +			xfs_warn(mp,
> +"max_open_zones mount option only supported on zoned file systems.");
> +			return -EINVAL;
> +		}
> +	}
> +
>  	return 0;
>  }
>  
> @@ -1462,6 +1474,9 @@ xfs_fs_parse_param(
>  		xfs_fs_warn_deprecated(fc, param, XFS_FEAT_NOATTR2, true);
>  		parsing_mp->m_features |= XFS_FEAT_NOATTR2;
>  		return 0;
> +	case Opt_max_open_zones:
> +		parsing_mp->m_max_open_zones = result.uint_32;
> +		return 0;
>  	default:
>  		xfs_warn(parsing_mp, "unknown mount option [%s].", param->key);
>  		return -EINVAL;
> -- 
> 2.45.2
> 
>