I read some of the topics related to the same problem, but have an additional behavior.
Experiencing mentioned issue. Notebook Asus VivoBook s15 s530u
Ubuntu 18.10 with kernel 4.18.0-13 generic.
Start point - replacement of HDD by SSD.
Installed SSD = ADATA SU800 512 GB;
SSD is mounted as /home
How it happens - randomly. What is going on - Some application freezes (last time it was Chrome, before that - system PDF reader). Ubuntu throws the message that application X is not responding and two options "Wait" or "Force Quit". Not depending on choice, my new one SSD is remounted as read-only disk. I can access and open the files, but can't create or write.
At the end: If I reboot - I receive COMRESET error and later journalctl writes that /home
was not mounted and drops me in grub. Another reboot return the same issue, but if I shutdown and then startup the notebook - everything is going fine and fast.
fchk - no mistakes; smartctl - no mistakes in long selftest; BIOS is updated; Ubuntu is reinstalled (in total with disks formatted);
I can try to update SSD firmware but this should be done under Windows (no Linux updater) and I, actually, don't wont to open notebook once again, but if this the only option...
Firmware update is not an option as I have the latest one.
Concerning the possibility to read files - I was wrong about that. I can read files only from Download folder. I think that this folder is shared somehow, as it should be accessible for applications from system SSD.