So, after my borked udev upgrade, I had some data corruption; I found one email containing half of another while in Thunderbird. Either I hit a software bug, a hardware bug or an unsafe unmount. Of the three, unsafe unmount is by far the most likely, so I added "data=ordered" to my fstab entries for my / and /boot mounts.
Go to reboot this morning, and X won't launch, and / is mounted read-only. Hidden away in dmesg is a line warning I can't change data mode on remount. So, if I can't set a data= parameter in /etc/fstab, where *do* I set it? -- :wq