Public bug reported: 1. do-release-upgrade should at least notify upon failure that there is a snapshot, and ideally explain the options (delete versus rollback). 2. There should be a command line parameter to make do-release-upgrade not snapshot even if the filesystem supports it.
Ironically, the failure was due to the snapshot using ~8 GiB and causing the root filesystem to run out of free space. There had been notification of the snapshot earlier in the upgrade process ... immediately after the download completed, i.e. at the point when one is no longer supposed to interrupt the process. When do- release-upgrade failed however, there was no notification that this snapshot still existed: Upgrading Inhibiting until Ctrl+C is pressed... Create a snapshot of '/tmp/apt-btrfs-snapshot-mp-9posd7z8/@' in '/tmp/apt-btrfs-snapshot-mp-9posd7z8/@apt-snapshot-release-upgrade-artful-2017-10-13_08:12:28' [many lines of apt output here] Installing new version of config file /etc/usb_modeswitch.conf ... dpkg: unrecoverable fatal error, aborting: unable to install updated status of 'usb-modeswitch': No space left on device Upgrade complete The upgrade has completed but there were errors during the upgrade process. To continue please press [ENTER] Because do-release-upgrade had cleaned up that mount in /tmp, manual cleanup had to involve re-mounting. To wit: # mount -t btrfs /dev/sda1 /mnt # btrfs subvolume delete /mnt/@apt-snapshot-release-upgrade-artful-2017-10-13_08\:12\:28 Delete subvolume (no-commit): '/mnt/@apt-snapshot-release-upgrade-artful-2017-10-13_08:12:28' # dpkg -a --configure [plus some manual fixes] ProblemType: Bug DistroRelease: Ubuntu 17.10 Package: ubuntu-release-upgrader-core 1:17.10.7 ProcVersionSignature: Ubuntu 4.13.0-15.16-generic 4.13.4 Uname: Linux 4.13.0-15-generic x86_64 ApportVersion: 2.20.7-0ubuntu3 Architecture: amd64 CrashDB: ubuntu CurrentDesktop: GNOME Date: Fri Oct 13 10:55:15 2017 InstallationDate: Installed on 2016-12-02 (314 days ago) InstallationMedia: Ubuntu-GNOME 16.10 "Yakkety Yak" - Release amd64 (20161012.1) PackageArchitecture: all SourcePackage: ubuntu-release-upgrader UpgradeStatus: Upgraded to artful on 2017-10-12 (0 days ago) ** Affects: ubuntu-release-upgrader (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug artful dist-upgrade wayland-session zesty2artful -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1723285 Title: do-release-upgrade failure leaves a btrfs snapshot To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1723285/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs