Comment 2 for bug 1908754

Digging into this a bit myself, it seems like this is due to a change in initramfs-tools. From my understanding of reading associated tickets and the NEWS item below, it was suggested to not use a separate /usr under LVM, or if you do, you must specify it by kernel name descriptor instead of by UUID or label.

https://sources.debian.org/src/initramfs-tools/0.139/debian/NEWS/#L43

While I never noticed the problem until Ubuntu 20.04, given the time of the change, it must have been something that was a part of previous Ubuntu versions as well for some time.

In any case, by changing /etc/fstab to reference /dev/mapper/vg01-usr in the Filesystem column, df and findmnt give the desired output. Both utilize /proc/self/mountinfo according to strace output, so naturally they all now have the desired information present. If instead /dev/vg01/usr is used in /etc/fstab, then that is shown in the df/findmnt output instead for /usr.

I think we can close this ticket, as this is outside of the scope of curtin itself.

Thanks.