239952e890
Normally, the udev rules operate on "change" events. But when coldplugging, there's an "add" event present. The udev rules have to recognize this and do some actions in this particular situation, too. Also, we don't want the nodes to be created prematurely on "add" events while not coldplugging. The udev rules will check DM_UDEV_PRIMARY_SOURCE_FLAG to see if the device was activated correctly before and if not, it ignore the "add" event totally. This way the udev rules can support udev triggers generating "add" events (e.g. "udevadm trigger --action=add" or "echo add > /sys/block/<dm_device>/uevent"). In this case, the udevd service is started after systemd-cryptsetup@config.service, is started, which will cause udevd service to miss the "change" uevent with DM_UDEV_PRIMARY_SOURCE_FLAG flag generated by systemd-cryptsetup@config.service. To solve this issue, we let the cryptsetup service be started after the udevd service.
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