Bug suddenly turns file system to read-only - No apparent trigger

Happened first after upgrading from 19.10 to 20.04 used it for a while until that happened. I then tried by formatting and made a clean install on an encrypted ext4 filesystem, installed some applications, used it for like an hour and it got back to the same spot. Wouldn't let me save any file, and when trying to suspend or reboot it displays a cascade of warnings about the read-only file system issue.

Besides upgrading to 20.04 the only difference with the software I was using on 19.10 is the Canonical Livepatch service.

I'll be formatting and switching back to 19.10 at least until 20.10 is available.
No support needed, just an input for developers.

First off, @javonaso, welcome to the community. It is a great pleasure to have you here.

Now let me tell you something from my experience. These kinds of problems are absolutely infuriating to the person who encounters these problems, I can tell you from first-hand (and zeroth-hand -- :wink:) experience.

I really suspect that an error was detected on the filesystem which caused the kernel to flag the filesystem as "tainted" and then mount it read-only. In ye olde days this used to happen to me a lot.

It's usually caused by a kernel bug.

My suggestion: Try performing a filesystem check on your Ext4 filesystem and see if there are errors. Even if there aren't, reboot after the filesystem check and see if the filesystem is mounted read-write again (perhaps temporarily). I'm guessing you can't log in to your system now, so I'd suggest you use a live version of 20.04 to check the filesystem.

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Had this happen to me twice, but in my case pc refused to boot after. Running a fsck on the decrypted disk /dev/mapper/vgubuntu--mate-root (do not mount) and then rebooting.
All started working again.

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I'm glad to hear the trick worked (at least temporarily...) for you at least.

I have some experience patching the kernel, but I need more information about this bug. Could someone please also post the errors / messages produced by fsck (if any), plus a copy of their /var/log/dmesg? This would be extremely valuable information.

If it occurs again I'll save you a log.