[systemd-devel] How to add a dependency to a systemd.mount that is activated by /bin/mount?

[Tim Landscheidt]

Hi,

on Fedora 19/systemd 204, I want systemd on "mount
/mnt/test" by a non-root user to automatically call a pro-
gram as root (in real life cryptsetup to unlock the underly-
ing device, for testing here echo) before the file system is
mounted and after it is unmounted.

With /etc/systemd/system/mount-wrapper.service:

| [Unit]
| Description=mount wrapper
| Before=mnt-test.mount
| StopWhenUnneeded=true

| [Service]
| Type=oneshot
| ExecStart=/bin/echo Unlock device.
| RemainAfterExit=true
| ExecStop=/bin/echo Lock device.

| [Install]
| RequiredBy=mnt-test.mount

/etc/fstab (partly):

| /dev/$DEVICE /mnt/test auto noauto,user 0 0

and (with or without) /etc/systemd/system/mnt-test.mount:

| [Unit]
| Description=mount test
|
| [Mount]
| What=/dev/$DEVICE
| Where=/mnt/test
| Options=noauto,user

this works (after daemon reload and enabling the service)
for "systemctl start mnt-test.mount" and "systemctl stop
mnt-test.mount" respectively (as root).

On "mount /mnt/test", however, "systemctl status
mnt-test.mount mount-wrapper" shows the latter service being
"inactive (dead)", while the former is "active (mounted)".

How can I (or can I not?) set up a dependency that is hon-
oured when /bin/mount is called as well?  The status of the
mount unit shows that "mount /mnt/test" seems to be trans-
lated to "ExecMount=/bin/mount /dev/$DEVICE /mnt/test -t
auto -o noauto,user", so apparently systemd gets notified.

TIA,
Tim

P. S.: If there is a "more systemd" way to handle removable
       encrypted media, I'm all ears :-).  I've seen
       /etc/crypttab & Co., but it seems to be focused on
       disks that are unlocked at boot and remain enabled
       till shutdown.