[Bug 1987679] Re: os-prober leaves filesystems (lvm-thin, lvm snap) mounted

[Aaron Rainbolt]

Using `|| true` scares me. If the value of `$type` matters at all, it
could contain invalid data at this point, which could confuse the
`$test` call done later. I would far prefer to see it done with an `||
echo 'bad'`, then unmount the filesystem and exit the script if `[ $type
= 'bad' ]`. I know there's precedent elsewhere in the codebase for doing
it with `|| true`, but really I feel like the way it's done in os-probes
is dangerous and should be replaced with a similar `|| echo 'bad'`
solution. Now, to be fair, I haven't studied the code too closely (time
constraints + tired at the moment), so it could be totally fine and I'm
worried about nothing.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to the bug report.
https://bugs.launchpad.net/bugs/1987679

Title:
  os-prober leaves filesystems (lvm-thin, lvm snap) mounted

Status in os-prober package in Ubuntu:
  In Progress
Status in os-prober source package in Focal:
  In Progress
Status in os-prober source package in Jammy:
  In Progress
Status in os-prober source package in Kinetic:
  Won't Fix
Status in os-prober source package in Noble:
  In Progress
Status in os-prober source package in Oracular:
  In Progress
Status in os-prober source package in Plucky:
  In Progress

Bug description:
  If one happens to have by accident (or on purpose) a thick LVM snapshot, or a thin-LV with a copy of a system on it, update-grub reports
  /sbin/grub-probe: error: unknown filesystem.
  Found Ubuntu 22.04.1 LTS on /dev/mapper/vgxubuntu-s22.04
  and
  /sbin/grub-probe: error: disk `lvmid/X7waXv-rMDA-5fQA-aw6l-ei1I-8Gz3-pQl3lr/k3Ze1u-Mfwc-pxUt-7fXa-FjSZ-7IkX-HAxf3b' not found.
  Found Ubuntu 22.04.1 LTS (22.04) on /dev/mapper/vgxubuntu-XR22.04.1U

  and leaves the systems mounted rw on /var/lib/os-prober/mount.
  On subsequent invocations update-grub spews out multiple
  mdir: failed to remove '/var/lib/os-prober/mount': Device or resource busy

  I'm pretty sure this also causes a new install to hang (though a
  power-reset seems to load the new system - not sure if it is complete
  or not.)

  The missing umounts should be relatively easy to fix, but the thick
  snapshot error is particularly vague as most users (I think) would
  take the "unknown filesystem" to refer to the previous entry.

  I have been playing with grub2-common-2.06-2ubuntu7 on xubuntu
  22.04.1, though I am sure this has been around a while

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/os-prober/+bug/1987679/+subscriptions