[Bug 1991478] [NEW] lost lvm PV (on top of LUKS) while attempting install of 22.04

[Alexandru Ungur]

Public bug reported:

I attempted to install 22.04 on top of existing 21.10 Ubuntu, while
retaining the existing root partition. The partition was setup as:

1) LUKS on /dev/sda3 then
2) LVM2 on top of the LUKS partition, with two VGs: root and swap.

When attempting to install, I did the following steps:

1. got all the way to manual setup of disks;
2. selected /dev/sda3 and used the "use it as encryption disk" option;
3. it asked me for a bunch of stuff: password and something about recovery. I assumed it was trying to unlock the existing LUKS volume. At the very least, I assumed it will NOT write anything to disks until I confirm everything. Turns out all that was wrong;
4. after that step, back to the list of partitions, the new luks partition was up, but I still didn't see anything LVM related. I expected to see the existing LVM volums so that I can select them for install.
5. at that point I decided to abort the install and hit quit.

Rebooted and started the old/existing Ubuntu and that throws me into
initramfs saying it cannot find encrypted volume with UUID=...

>From initramfs I can decrypt the volume, but there's nothing on it, no
LVM, nothing.

I also booted the live usb (22.04) and I can decrypt the volume, but
pvscan comes out empty.

My guess is, that the luks partition, instead of being opened when I
selected it, it was re-initialized, without any warning or confirmation
whatsoever. I only expected data to be written at the next step, after
completing all the changes to the disks/partitions during install. I
would expected a warning that I will permanently loose my data, BEFORE
loosing my data. None of that happened.

-------------------

I repeated the exact same steps, on a different machine. The only change
was that the existing Ubuntu version was 20.04. Following the same
steps, resulted in the exact same data loss. I could get past the
"encrypted volume not found" error, by changing the luks UUID to the
desired UUID. It then boots normally up the the encryption part, I enter
the password, it decrypts it but then back to initramfs as the root
volume is not found.

I guess the bug report is: loosing data when trying to setup partitions
and BEFORE confirming that I actually want to apply the changes to the
disk. Having changes be written before confirmation was certainly
unexpected.

I would really appreciate if you could confirm what actually happened
here so that I can look for next steps.

Thank you!

** Affects: ubiquity (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: dataloss luks lvm ubiquity

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https://bugs.launchpad.net/bugs/1991478

Title:
  lost lvm PV (on top of LUKS) while attempting install of 22.04

Status in ubiquity package in Ubuntu:
  New

Bug description:
  I attempted to install 22.04 on top of existing 21.10 Ubuntu, while
  retaining the existing root partition. The partition was setup as:

  1) LUKS on /dev/sda3 then
  2) LVM2 on top of the LUKS partition, with two VGs: root and swap.

  When attempting to install, I did the following steps:

  1. got all the way to manual setup of disks;
  2. selected /dev/sda3 and used the "use it as encryption disk" option;
  3. it asked me for a bunch of stuff: password and something about recovery. I assumed it was trying to unlock the existing LUKS volume. At the very least, I assumed it will NOT write anything to disks until I confirm everything. Turns out all that was wrong;
  4. after that step, back to the list of partitions, the new luks partition was up, but I still didn't see anything LVM related. I expected to see the existing LVM volums so that I can select them for install.
  5. at that point I decided to abort the install and hit quit.

  Rebooted and started the old/existing Ubuntu and that throws me into
  initramfs saying it cannot find encrypted volume with UUID=...

  From initramfs I can decrypt the volume, but there's nothing on it, no
  LVM, nothing.

  I also booted the live usb (22.04) and I can decrypt the volume, but
  pvscan comes out empty.

  My guess is, that the luks partition, instead of being opened when I
  selected it, it was re-initialized, without any warning or
  confirmation whatsoever. I only expected data to be written at the
  next step, after completing all the changes to the disks/partitions
  during install. I would expected a warning that I will permanently
  loose my data, BEFORE loosing my data. None of that happened.

  -------------------

  I repeated the exact same steps, on a different machine. The only
  change was that the existing Ubuntu version was 20.04. Following the
  same steps, resulted in the exact same data loss. I could get past the
  "encrypted volume not found" error, by changing the luks UUID to the
  desired UUID. It then boots normally up the the encryption part, I
  enter the password, it decrypts it but then back to initramfs as the
  root volume is not found.

  I guess the bug report is: loosing data when trying to setup
  partitions and BEFORE confirming that I actually want to apply the
  changes to the disk. Having changes be written before confirmation was
  certainly unexpected.

  I would really appreciate if you could confirm what actually happened
  here so that I can look for next steps.

  Thank you!

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