Re: [RFC PATCH v3 1/3] common/xfs: add a _require_xfs_shrink helper

[Eryu Guan <guan@eryu.me>]

On Mon, Mar 15, 2021 at 07:19:24PM +0800, Gao Xiang wrote:
> In order to detect whether the current kernel supports XFS shrinking.
> 
> Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
> ---
>  common/xfs | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/common/xfs b/common/xfs
> index 2156749d..ea3b6cab 100644
> --- a/common/xfs
> +++ b/common/xfs
> @@ -432,6 +432,17 @@ _supports_xfs_scrub()
>  	return 0
>  }
>  
> +_require_xfs_shrink()
> +{
> +	_require_scratch

_require_command "$XFS_GROWFS_PROG" xfs_growfs

> +
> +	_scratch_mkfs_xfs > /dev/null
> +	_scratch_mount
> +	$XFS_GROWFS_PROG -D1 "$SCRATCH_MNT" 2>&1 | grep -q 'Invalid argument' || \
> +		_notrun "kernel does not support shrinking"

Better to describe the behavior here to explain why EINVAL means kernel
supports shrink.

Thanks,
Eryu

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