** Also affects: e2fsprogs (Ubuntu Noble) Importance: Critical Assignee: Matthew Ruffell (mruffell) Status: In Progress
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to e2fsprogs in Ubuntu. https://bugs.launchpad.net/bugs/2036467 Title: Resizing cloud-images occasionally fails due to superblock checksum mismatch in resize2fs Status in cloud-images: New Status in e2fsprogs package in Ubuntu: In Progress Status in e2fsprogs source package in Trusty: Won't Fix Status in e2fsprogs source package in Xenial: Won't Fix Status in e2fsprogs source package in Bionic: Won't Fix Status in e2fsprogs source package in Focal: In Progress Status in e2fsprogs source package in Jammy: In Progress Status in e2fsprogs source package in Lunar: Won't Fix Status in e2fsprogs source package in Mantic: In Progress Status in e2fsprogs source package in Noble: In Progress Bug description: [Impact] This is a long running bug plaguing cloud-images, where on a rare occasion resize2fs would fail and the image would not resize to fit the entire disk. Online resizes would fail due to a superblock checksum mismatch, where the superblock in memory differs from what is currently on disk due to changes made to the image. $ resize2fs /dev/nvme1n1p1 resize2fs 1.47.0 (5-Feb-2023) resize2fs: Superblock checksum does not match superblock while trying to open /dev/nvme1n1p1 Couldn't find valid filesystem superblock. Changing the read of the superblock to Direct I/O solves the issue. [Testcase] Start an c5.large instance on AWS, and attach a 60gb gp3 volume for use as a scratch disk. Run the following script, courtesy of Krister Johansen and his team: #!/usr/bin/bash set -euxo pipefail while true do parted /dev/nvme1n1 mklabel gpt mkpart primary 2048s 2099200s sleep .5 mkfs.ext4 /dev/nvme1n1p1 mount -t ext4 /dev/nvme1n1p1 /mnt stress-ng --temp-path /mnt -D 4 & STRESS_PID=$! sleep 1 growpart /dev/nvme1n1 1 resize2fs /dev/nvme1n1p1 kill $STRESS_PID wait $STRESS_PID umount /mnt wipefs -a /dev/nvme1n1p1 wipefs -a /dev/nvme1n1 done Test packages are available in the following ppa: https://launchpad.net/~mruffell/+archive/ubuntu/lp2036467-test If you install the test packages, the race no longer occurs. [Where problems could occur] We are changing how resize2fs reads the superblock from underlying disks. If a regression were to occur, resize2fs could fail to resize offline or online volumes. As all cloud-images are online resized during their initial boot, this could have a large impact to public and private clouds should a regression occur. [Other info] Upstream mailing list discussion: https://lore.kernel.org/linux-ext4/20230605225221.ga5...@templeofstupid.com/ https://lore.kernel.org/linux-ext4/20230609042239.ga1436...@mit.edu/ This was fixed in the below commit upstream: commit 43a498e938887956f393b5e45ea6ac79cc5f4b84 Author: Theodore Ts'o <ty...@mit.edu> Date: Thu, 15 Jun 2023 00:17:01 -0400 Subject: resize2fs: use Direct I/O when reading the superblock for online resizes Link: https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/commit/?id=43a498e938887956f393b5e45ea6ac79cc5f4b84 The commit has not been tagged to any release. All supported Ubuntu releases require this fix, and need to be published in standard non- ESM archives to be picked up in cloud images. To manage notifications about this bug go to: https://bugs.launchpad.net/cloud-images/+bug/2036467/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp