Filesystem seems to be in a read only state.

df -h shows nothing mounted.

/etc/mtab is blank
/etc/fstab has entries

If I reboot the phone, it reverts back to its state from Jan 25th.

I've tried, after sudo gainroot

mount -o remount,rw /
complains about no entry in /etc/mtab, expected behavior

mount -a
complains failed: invalid argument

Thoughts?
More info I can provide?

after sudo gainroot try:
mount -n -o,remount,rw /

edit: sorry for the typo before...

No luck.

Reports:
mount: can't find / in /etc/mtab

what exactly is your problem?
can't you write to your home-directory?

Wow, that can be answered in so many ways!

Seriously:

I used vi and created a test file in MyDocs/tmp/. That file survived a power off / on. I can read the file.

However, things like settings for what mode I am in, what email I last read, what calls display in my call log, etc, all revert to as the state was on Jan 25th. Plus, shouldn't df -h show me the mounts and the amount of space they are using?

For example:
Currently my phone is in online mode. If I power cycle, I am asked if I want to leave Offline mode.
Currently my phone has no status lights or icons. Power cycle it and I have a notification that I have new email. That email is from yesterday. Leave it on and messages come through until I poer cycle.
Nothing is being saved to my call logs even though I have made and received several calls. My call log shows the last call to be Jan 24th.

mhm.. ok...
1. you have rw-access to MyDocs as normal user, right?
2. do you have rw-access to admin-folders (like /etc or /usr etc) as root?

As normal user it appears I can read and write in MyDocs as creating my test file worked.

As normal user, trying to write to /etc/ I received the expected permission denied.

As root, trying to write to /etc/ I received "/etc/test" No space left on device

mhm...
go to your preferences and take a look at the "storage" in the general block.
what does it say?

Memory
Nokia N900
25.24 GB available
Memory for installable applications
1.75 GB

Selecting the Details button:

Storage Details
Name Nokia N900
Type Device memory
Total Size 27.22 GB
In use by system 227.9 MB
User Files 1.76 GB
Available 25.24 GB

Solution - Reflash.
Filesystems back and seen by using df -h