RlndVt

How I mount my encrypted bcachefs array at boot.

In /etc/fstab/ include a x-systemd.requires=unlock-bcachefs-vault.service mount option. This service does the unlocking before the mount is triggered. Example line as in my /etc/fstab:

UUID=bf512699-6643-4d96-a793-daaf3f1d34f1 /mnt/vault bcachefs nofail,x-systemd.requires=unlock-bcachefs-vault.service 0 0

The content of the unlock service:

RlndVt

Bus 001 Device 003: ID 06cb:00bd Synaptics, Inc. 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          255 Vendor Specific Class
  bDeviceSubClass        16 
  bDeviceProtocol       255 
  bMaxPacketSize0         8
  idVendor           0x06cb Synaptics, Inc.