Samba dfree and zfs on Ubuntu 14.04

etc-samba-smb.conf

# File: /etc/samba/smb.conf

dfree command = /usr/local/bin/dfree

etc-sudoers

# File: /etc/sudoers

ALL ALL = NOPASSWD: /usr/local/bin/zfs-get-used, /usr/local/bin/zfs-get-available

usr-local-bin-dfree.sh

#!/bin/bash
# File: /usr/local/bin/dfree

CUR_PATH=$PWD
FILESYSTEM=$(df -PT $CUR_PATH | tail -1 | awk '{print $2}')

if [ $FILESYSTEM = 'zfs' ]; then
  USED=$(sudo zfs-get-used $CUR_PATH)
  AVAIL=$(sudo zfs-get-available $CUR_PATH)

  AVAIL_KB=$(expr $AVAIL / 1024)
  TOTAL_KB=$(expr $USED / 1024 + $AVAIL / 1024)

  echo $TOTAL_KB $AVAIL_KB
else
  df -PT $CUR_PATH | tail -1 | awk '{print $3" "$5}'
fi

usr-local-bin-zfs-get-available.sh

#!/bin/bash
# File: /usr/local/bin/zfs-get-available

zfs get -o value -Hp available $1

usr-local-bin-zfs-get-used.sh

#!/bin/bash
# File: /usr/local/bin/zfs-get-used

zfs get -o value -Hp used $1

Confirm it works on Archlinux 4.6.4-1-ARCH, Samba 4.4.5-1, ZFS 0.6.5.7_4.6.4_1-1, Win8.1 Pro

Also works on AlpineLinux

Kernel: 6.1.56-0-lts
Samba: 4.18.5-r0
ZFS: 2.1.11-1
Client: Win 11 Pro