[Unit]
Before=dovecot-chroot.service postfix-chroot.service postfix-chroot@-.service 
PartOf=chr-maild.target

[Mount]
What=/srv/mail
Where=/chroot/maild/var/mail
Type=none
Options=defaults,noexec,nosuid,nodev,bind,rprivate,nofail

[Install]
WantedBy=chr-maild.target