Re: [RFC PATCH v2 1/3] common/xfs: add a _require_xfs_shrink helper

[Zorro Lang <zlang@redhat.com>]

On Fri, Mar 12, 2021 at 09:22:58PM +0800, Gao Xiang wrote:
> In order to detect whether the current kernel supports XFS shrinking.
> 
> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> ---
> use -D1 rather than -D0 since xfs_growfs would report unchanged size
> instead.
> 
>  common/xfs | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/common/xfs b/common/xfs
> index 2156749d..326edacc 100644
> --- a/common/xfs
> +++ b/common/xfs
> @@ -432,6 +432,16 @@ _supports_xfs_scrub()
>  	return 0
>  }
>  
> +_require_xfs_shrink()
> +{
> +	_scratch_mkfs_xfs >/dev/null 2>&1
> +
> +	_scratch_mount
> +	$XFS_GROWFS_PROG -D1 "$SCRATCH_MNT" 2>&1 | grep -q 'Invalid argument' || { \
> +		_scratch_unmount; _notrun "kernel does not support shrinking"; }
	        ^^^^
		I think this unmount isn't necessary, due to after "_notrun" the
		$SCRATCH_DEV will be umounted "automatically".

> +	_scratch_unmount
> +}
> +
>  # run xfs_check and friends on a FS.
>  _check_xfs_filesystem()
>  {
> -- 
> 2.27.0
>