Re: [PATCH v5 1/3] common/xfs: add _require_xfs_scratch_shrink helper

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

On Tue, May 11, 2021 at 03:39:43PM +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 | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/common/xfs b/common/xfs
> index 69f76d6e..184aa01e 100644
> --- a/common/xfs
> +++ b/common/xfs
> @@ -766,6 +766,26 @@ _require_xfs_mkfs_without_validation()
>  	fi
>  }
>  
> +_require_xfs_scratch_shrink()
> +{
> +	_require_scratch
> +	_require_command "$XFS_GROWFS_PROG" xfs_growfs
> +
> +	_scratch_mkfs_xfs | _filter_mkfs 2>$tmp.mkfs >/dev/null
> +	. $tmp.mkfs
> +	_scratch_mount
> +	# here just to check if kernel supports, no need do more extra work
> +	errmsg=$($XFS_GROWFS_PROG -D$((dblocks-1)) "$SCRATCH_MNT" 2>&1)
> +	if [ "$?" -ne 0 ]; then
> +		echo "$errmsg" | grep 'XFS_IOC_FSGROWFSDATA xfsctl failed: Invalid argument' && \
> +			_notrun "kernel does not support shrinking"
> +		echo "$errmsg" | grep 'data size .* too small, old size is ' && \
> +			_notrun "xfsprogs does not support shrinking"
> +		_fail "$XFS_GROWFS_PROG failed unexpectedly"

Silly nit: why not print $errmsg in the fail string?

With that fixed,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> +	fi
> +	_scratch_unmount
> +}
> +
>  # XFS ability to change UUIDs on V5/CRC filesystems
>  #
>  _require_meta_uuid()
> -- 
> 2.27.0
>