[Bug 1779292] Re: GParted fails to shrink an LVM PV with lvm2 >= 2.02.171

[Jeremy Bicha]

** Changed in: gparted (Ubuntu Bionic)
       Status: Triaged => In Progress

** Changed in: gparted (Ubuntu Bionic)
     Assignee: (unassigned) => Thomas Ward (teward)

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Title:
  GParted fails to shrink an LVM PV with lvm2 >= 2.02.171

Status in gparted package in Ubuntu:
  Fix Released
Status in gparted source package in Bionic:
  In Progress

Bug description:
  [Impact]

  GParted in Bionic uses LVM2 versions >= 2.02.172.  Because of this
  higher LVM version, the confirmation prompt added to the pvresize
  system makes all LVM2 resize operations involving shrinking (and
  possibly expanding) LVM Physical Volumes fail because of unexpected
  output.

  As such, gparted on Bionic cannot be used to resize LVM physical
  partitions.

  This was fixed by syncing a newer version from Debian in Cosmic
  series, however still impacts the Bionic series.  If we intend to have
  Bionic as an LTS (as we do), then we need to patch this.

  [Test Case]

  (0) Prerequisites: A drive with an LVM2 partition on it for the PV,
  and a VG with LVs within that do NOT take up the entirety of the LVM2
  partition (so for a 100GB LVM PV, consume anything less than that so
  we can resize the PV; you may resize LVs for this if you need to).

  With existing software versions:

  (1) Boot up a LiveCD/LiveUSB, open `gparted` on it.

  (2) Attempt to resize with current gparted on the repos / image.

  Current Result: ERROR due to unexpected message.

  With patched version:

  (1) Boot up LiveCD/LiveUSB

  (2) Install PPA version of `gparted` (or from -proposed if this has
  landed in proposed for verification)

  (3) Attempt to shrink PV to make some free space (provided that step 0
  is met).

  Expected Result: SUCCESS

  [Regression Potential]

  Messing with gparted could lead to other problems,  This is always a
  risk.  The potential for regression on this is low, however, provided
  that the patch is applied carefully.

  The patch literally only changes the the arguments passed to pvresize
  of --yes to 'confirm' that we want to do the changes.  This change is
  already applied in upstream versions later than that in Bionic,
  therefore the regression risk of this is low.

  [Other Info]

  This was test-built and *actively tested* in a PPA with the upstream
  patch (or rather, the patch listed in this bug initially).  I (Thomas
  Ward, who applied the SRU template here) got the upstream patch for
  the debdiff from upstream's master repository for the patch included
  in the debdiff.
  (https://gitlab.gnome.org/GNOME/gparted/commit/5892b72890748c1d3e96bd7e25800c8aab351025)

  Note that the PPA was tested from a LiveUSB of 18.04.1(.0) and was
  used on a production system to resize the PV of my 18.04 laptop so I
  could put a new partition with Clonezilla Live-HDD version on it.  It
  works if you wish to test it, even though it uses the patch originally
  attached and not a patch pulled directly from upstream's master
  branches/repos.

  [Original Bug Description]

  == GParted fails to shrink the LVM2 PV reporting this

  # lvm pvresize -v --setphysicalvolumesize 786432K '/dev/sda9'
  0 physical volume(s) resized / 1 physical volume(s) not resized

  Wiping internal VG cache
  Wiping cache of LVM-capable devices
  /dev/sda9: Requested size 712.00 MiB is less than real size 1.00 GiB.  Proceed? [y/n]:[n]
  Physical Volume /dev/sda9 not resized.

  == Confirmed on Ubuntu 18.04 LTS with these packages

  $ dpkg -l lvm2 gparted
  Desired=Unknown/Install/Remove/Purge/Hold
  | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
  |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
  ||/ Name                  Version         Architecture    Description
  +++-=====================-===============-===============-================================================
  ii  gparted               0.30.0-3ubuntu1 amd64           GNOME partition editor
  ii  lvm2                  2.02.176-4.1ubu amd64           Linux Logical Volume Manager

  == Relevant bug references

  Issue #1 - Can't shrink LVM partition due to pvresize prompt
  https://gitlab.gnome.org/GNOME/gparted/issues/1

  Bug 1460577 - regression: lvm2 pvresize command suddenly became interactive, breaking automated usage
  https://bugzilla.redhat.com/show_bug.cgi?id=1460577

  == Attached patch

  Attached is the upstream patch to workaround the change in pvresize.
  Patch applies to gparted >= 0.14.0.

  ProblemType: Bug
  DistroRelease: Ubuntu 18.04
  Package: gparted 0.30.0-3ubuntu1
  ProcVersionSignature: Ubuntu 4.15.0-23.25-generic 4.15.18
  Uname: Linux 4.15.0-23-generic x86_64
  ApportVersion: 2.20.9-0ubuntu7.2
  Architecture: amd64
  CurrentDesktop: XFCE
  Date: Fri Jun 29 10:35:14 2018
  InstallationDate: Installed on 2018-03-12 (108 days ago)
  InstallationMedia: Xubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180306.1)
  SourcePackage: gparted
  UpgradeStatus: No upgrade log present (probably fresh install)

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