Follow-up for
d120ce478dc0043c89899799b5c1aaf62901bea9
blockdev@.target is used as a synchronization point between
the mount unit and corresponding systemd-cryptsetup@.service.
After the mentioned commit, it doesn't get a stop job enqueued
during shutdown, and thus the stop job for systemd-cryptsetup@.service
could be run before the mount unit is stopped.
Therefore, let's make blockdev@.target conflict with umount.target,
which is also what systemd-cryptsetup@.service does.
Fixes #29336
[Unit]
Description=Block Device Preparation for %f
Documentation=man:systemd.special(7)
+
DefaultDependencies=no
+Conflicts=umount.target
+Before=umount.target
+
StopWhenUnneeded=yes