George, You've found a bug. I've got a reproducer. https://github.com/kdave/btrfs-progs/issues/349 Both the ext4 rollback file, ext2_saved/image, and the converted btrfs file system are OK. The corruption is bogus, so the bug is that somehow checksums on a handful of specific blocks (not random) are computed incorrectly. Btrfs integrity checking sees these blocks as corrupt, refuses to hand over those blocks when trying to mount the ext4 file system, and therefore mount fails because the ext4 superblock can't be read. The rollback will still work. But of course that means you lose the btrfs file system and everything on it - it goes back to the state it was in before conversion. Another idea is a workaround that I've tested that's probably a lot more convenient. First, you need a 5.11 or newer kernel. mount -o ro,rescue=all /dev/sda8 /mnt/btrfs mount -o ro,loop /mnt/btrfs/ext2_saved/image /mnt/oldext4 That's it. You'll be able to inspect /mnt/oldext4 for the files you've accidentally deleted. Of course you can't copy files to /mnt/btrfs because it's read-only. -- Chris Murphy _______________________________________________ test mailing list -- test@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to test-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/test@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
