Hi all,
I've been cryptsetup and LUKS-encryption a lot in the past 5 years and the only time I've really lost data is because I locked myself out of my linux boot-partition during a kernel upgrade/initramfs-generation (still not sure what happened, but I've learned now that I should ALWAYS have a backup password instead of relying on a key which I lost). But the last 3-4 days scared the shit out of me, as I took a complete backup of maybe 15 years of data (5-6 TB), verified with md5sum that the copy also was ok - but in order to have space for that (~5-6 TB) I deleted my previous unencrypted backup, otherwise I had to buy a new disk and I trusted things were ok... When I saw the md5sum on the backup disk was ok, I felt "safe" and wanted to unlock my partition (just after deleting the unencrypted data, to have space). I used cryptsetup on a Debian (proxmox)-installation where the encrypted data was also stored and it worked before doing the backup. But after making the backup I got something like:
"mount: wrong fs type, bad option, bad superblock on /dev/mapper/...., missing codepage or helper program, or other error
At first I thought it was simple: I googled and found out I should use e2fsck with an option to use another superblock. I read I should try the first, reboot, then the next, reboot, etc - until I've went through them all or until it works.... It didn't work - I was shocked, I thought I had made the mistake of my life and lost all my data...
Nothing on google pointed me to the solution - I was screwed - I thought. I think the problem happened because I was primarily using Debian / proxmox (where the encrypted data is) with cryptsetup 2.1.0. But it might have happened that just before doing the backup, I had "sshfs'ed" to my laptop with Arch Linux, which is using cryptsetup 2.3.4. I think after opening the LUKS-container with cryptsetup 2.3.4 (and closing it again after use, hence probably forcing some things to be written), the encrypted data couldn't - and cannot be opened with cryptsetup 2.1.0 anymore... At least this was/is the solution for me: Don't use debian/proxmox with cryptsetup 2.1.0 anymore, instead use Arch Linux with version 2.3.4... I'm still terrified - but tried to investigate the difference with luksDump (encrypted file). It says LUKS is version 2, epoch 3, pbkdf2 is used, aes-xts-plain64 cipher with 512 bits key - and everything is completely the same using both luksDump-versions...
I tried to look in version history but am not into the details of the difference in crypt-setup versions. Can anyone please tell why I got/get this error using 2.1.0 and not with 2.3.4?
"mount: wrong fs type, bad option, bad superblock on /dev/mapper/...., missing codepage or helper program, or other error
Questions that popup are: Is there a fix? Is it recommended to stick with 2.3.4? Should I worry in the future?
I would be grateful to understand this better, to not screw up in the future. Furthermore, I think or hope this could/can maybe help others, as I didn't found this solution on google or any other place. I almost gave up all hope and was prepared to delete the LUKS-container, before I thought I would try this "long shot" - phew, I'm just happy I have my data back. Please elaborate or explain the version difference together with your comments, I would be very grateful for that, thanks!
Br,
M.
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