Filesystems may be remounted read only on error. I’d expect that to be reverted post reboot, but maybe your error was big enough for it not to? You may want to search how to perform an fsck on the affected partitions.

I think bazzite uses systemd.

You can use journalctl to see the logs and find out what happened. They’re pretty straightforward to understand.

E: journalctl, not systemctl.

It might also be worth ruling out low-level issues:

• Check for anything strange in the BIOS related to disks (fwupdmgr can automatically install BIOS updates from a live Linux session. I don’t know if Bazzite does this)
• Try using a different SATA port
• Run some SMART tests on your drives

I am not familiar with I/O stuff, but I didn’t see you mention if you tried doing an rpm-ostree rollback.

Since you said it happened after an update, did you already try that to see if it fixes your issue? Another thing to look at is topgrade. It’s the underlying tool for Bazzite upgrades, so perhaps that can give you some clues as to what went wrong.

ETA: Have you tried asking in their discord? The community and devs are really nice and generally pretty helpful.

Can you restore a backup image? Sometimes that’s easier to roll back a day rather than spend all the time trying to troubleshoot.

Boot from a livecd and figure out what is going on.

Just a shot in the dark:
Backup your fstab, then edit it to mount the drives to a subdirectory of your home.
Maybe that’ll get you back access.

Is anything going down in the system log when you mount a drive, or trigger an access error? If it’s (one of the many) security systems clamping down, they tend to log that.

Can you read/write to the disks as root? If so, then something has likely gone sideways with your fstab entry. For example, the device name, order, or UID/GID may have changed, depending on how you’ve configured the entry.

It’s difficult to assist much more without seeing the contents of /etc/fstab.