How to mount LVM images
You want to read your LVM image (e.g., there is a problem where you can’t start any VMs except dom0).
1: make the image available for qubesdb. From dom0 terminal:
# Example: /dev/qubes_dom0/vm-debian-9-tmp-root
[user@dom0]$ dev=$(basename $(readlink /dev/YOUR_LVM_VG/YOUR_LVM_IMAGE))
[user@dom0]$ qubesdb-write /qubes-block-devices/$dev/desc "YOUR_LVM_IMAGE"
2: Create a new disposable VM
[user@dom0]$ qvm-run -v --dispvm=YOUR_DVM_TEMPLATE --service qubes.StartApp+xterm &
3: Attach the device to your newly created disp VM
From the GUI, or from the command line:
[user@dom0]$ qvm-block attach NEWLY_CREATED_DISPVM dom0:$dev
4: Mount the partition you want to, and do what you want with it
[user@dispXXXX]$ mount /dev/xvdiX /mnt/
5: Umount and kill the VM
[user@dispXXXX]$ umount /mnt/
6: Remove the image from qubesdb
[user@dom0]$ qubesdb-rm /qubes-block-devices/$dev/
References
Please consult this issue’s comment.