Systemd does not umount in spite of StopWhenUnneeded=true

Question

Before going into details I have to say that although I am a seasoned Linux user, I am a noob to both systemd and Arch.
My goal is to setup a backup routine that starts automatically upon connection of the relevant USB storage which cleans up after itself (i.e.: umounts).
With the help of this resource, I got the first half running. But systemd does not umount.
This is the code:
/etc/udev/rules.d/00-luks-usb.rules
ACTION=="add", \
KERNEL=="sd*", \
SUBSYSTEM=="block", \
ATTRS{manufacturer}=="Western Digital", \
ATTRS{serial}=="theserial", \
ATTRS{product}=="Elements 1078", \
SYMLINK="schwarzeplatte%n", \
RUN+="/sbin/cryptsetup luksOpen $env{DEVNAME} schwarzeplatte --key-file /home/user/Dokumente/arbeiten/keys/usbbackup.lukskey", \
TAG+="systemd", \
ENV{SYSTEMD_WANTS}="usbbackup.service"
ACTION=="remove", \
ENV{ID_SERIAL}=="theserial", \
RUN+="/sbin/cryptsetup luksClose schwarzeplatte"
/etc/systemd/system/usbbackup.service
[Unit]
Description=script to backup user data onto encrypted external USB storage
BindsTo=dev-mapper-schwarzeplatte.device var-run-media-user-schwarzeplatte.mount
After=dev-mapper-schwarzeplatte.device var-run-media-user-schwarzeplatte.mount
RefuseManualStart=true
[Service]
ExecStart=/usr/local/sbin/usbbackup.sh
/etc/systemd/system/var-run-media-user-schwarzeplatte.mount
[Unit]
DefaultDependencies=no
Conflicts=umount.target
Before=umount.target
StopWhenUnneeded=true
[Mount]
What=/dev/mapper/schwarzeplatte
Where=/var/run/media/user/schwarzeplatte/
Type=ext4
/etc/fstab
/dev/mapper/schwarzeplatte /var/run/media/user/schwarzeplatte/ ext4 noauto,x-systemd.automount,x-systemd.device-timeout=10 0 2
/etc/crypttab
schwarzeplatte UUID=the-uuid /home/user/Dokumente/arbeiten/keys/usbbackup.lukskey luks,noauto
The unit dev-mapper-schwarzeplatte is created automatically.
I searched for where dependencies might be and tried the following, but it did not lead me to anything.
$ sudo systemctl list-dependencies var-run-media-user-schwarzeplatte.mount
var-run-media-user-schwarzeplatte.mount
● ├─-.mount
● ├─dev-mapper-schwarzeplatte.device
● └─system.slice
$ sudo systemctl list-dependencies var-run-media-user-schwarzeplatte.mount --reverse
var-run-media-user-schwarzeplatte.mount
● └─dev-mapper-schwarzeplatte.device
Does anyone have insight what I should do?
(Bonus question: How could a desktop notification [KDE] be fired once the backup has finished, detailing the result?)
Thank you for reading!

Answer 1

You could see if there are any messages written to the logs, if you have a terminal open with this running:
journalctl -f
then plug the thing in and see what happens when it is meant to umount.
grafzakenbarsch wrote:(Bonus question: How could a desktop notification [KDE] be fired once the backup has finished, detailing the result?)
I don't use KDE but may be pipe it through osd_cat? e.g.
echo "NOTIFIED\!" | osd_cat -d10
Last edited by myles (2015-03-07 20:47:31)