|look here, specifically at the section:
Q: I updated ext3 today. Got all of my mounts converted. Now on boot, I see: “EXT3-fs: mounted filesystem with ordered data mode”. Is this normal?
it mentions that you might see displayed what mode you are in at boot up, i assume when the filesystems are mounted at boot-time.
that section also goes on to explain what the default modes are for v1 & v2, and what the mount options are to mount in a different mode (which you would place in /etc/fstab if you want the options to take effect each boot).
sorry, i know the referenced faq doesn’t directly answer your question, but it’s the best explanation i’ve found on the web. you might want to try the ext3 man page or docs that accompany the official ext3 code (on andrew morton’s website?).
btw, does anybody know if the ext3 forced sync issue has been addressed? i have a laptop, and the fact that ext3 bypasses the kernel syncing mechanism, insures that my laptop’s harddrive never spins down as ext3 syncs every 5 seconds.