Re: [PATCH 01/11] common/xfs: Add a helper to get an inode fork's extent count

Darrick J. Wong
2020-11-14T00:10:37Z

On Fri, Nov 13, 2020 at 04:56:53PM +0530, Chandan Babu R wrote:
> This commit adds the helper _scratch_get_iext_count() which returns an
> inode fork's extent count.
>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
> ---
> common/xfs | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/common/xfs b/common/xfs
> index 79dab058..45cd329c 100644
> --- a/common/xfs
> +++ b/common/xfs
> @@ -883,6 +883,28 @@ _scratch_get_bmx_prefix() {
> return 1
> }
>
> +_scratch_get_iext_count()
> +{
> + ino=$1
> + whichfork=$2
> +
> + case $whichfork in
> + "attr")
> + field=core.naextents
> + ;;
> + "data")
> + field=core.nextents
> + ;;
> + *)
> + return 1
> + esac
> +
> + nextents=$(_scratch_xfs_db -c "inode $ino" -c "print $field")
> + nextents=${nextents##${field} = }

This helper looks fine, but looking at the callers spread over the next
10 patches, I notice that you unmount to call this helper and
immediately remount the fs.

I wonder, is there a specific reason for grabbing the extent count that
way? You can extract the same info online with `xfs_io -c 'stat' /moo',
right?

--D

> +
> + echo $nextents
> +}
> +
> #
> # Ensures that we don't pass any mount options incompatible with XFS v4
> #
> --
> 2.28.0
>