ORLY?
D*#n

That indeed leads me to another assumption:
please open x-term and do
and resp.
Could it be that you have lot of applications and/or personal data on the rootfs or home partition.
As not showing up of SMS was a symptom of full rootfs!

Don't think so

df -h
Filesystem Size Used Available Use% Mounted on
rootfs 227.9M 141.0M 82.7M 63% /
ubi0:rootfs 227.9M 141.0M 82.7M 63% /
tmpfs 1.0M 112.0k 912.0k 11% /tmp
tmpfs 256.0k 88.0k 168.0k 34% /var/run
none 10.0M 84.0k 9.9M 1% /dev
tmpfs 64.0M 4.0k 64.0M 0% /dev/shm
/dev/mmcblk0p2 2.0G 606.4M 1.3G 32% /home
/home/opt 2.0G 606.4M 1.3G 32% /opt
/opt/pymaemo/usr/lib/python2.5
2.0G 606.4M 1.3G 32% /usr/lib/python2.5
/opt/pymaemo/usr/share/pyshared
2.0G 606.4M 1.3G 32% /usr/share/pyshared
/opt/pymaemo/usr/lib/pyshared
2.0G 606.4M 1.3G 32% /usr/lib/pyshared
/opt/pymaemo/usr/share/python-support
2.0G 606.4M 1.3G 32% /usr/share/python-support
/opt/pymaemo/usr/lib/python-support
2.0G 606.4M 1.3G 32% /usr/lib/python-support
/dev/mmcblk0p1 27.0G 122.3M 26.9G 0% /home/user/MyDocs
/dev/mmcblk1p1 3.7G 2.4G 1.3G 66% /media/mmc1

df -i says invalid option
Testdisk found some unrecoverable sectors a the end off the LBA

And that is completely, absolutely and in all other ways inconceivable!

@sirvival, I suspect you are on the right track and your eMMC is on its last leg. Sorry, but I do not know about any on-device tools for marking bad sectors. When you come home, you can use Boot menu to export your partitions and do the magic on the big PC.

Okay...

but at least eMMC is full up to the roof
So clearing up some space would be first step, move big chunks to the SD card.

df -igittigiit is the option not mysreading/typing df -laberlaber

Might be, might be not. It may be an illusion caused by the corruption.

But I agree, copy (not move, as moving involves deleting i.e. writing which may exacerbate the problem) stuff you want to salvage somewhere else and then just reformat the partition (tap and hold in File Manager until the option pops up). It is by far the easiest and most reliable method. As a bonus, it should also find and mark bad sectors

strange:

Nokia-N900:/home/user# du -hs
du: ./MyDocs/.maps: Input/output error
395.4M .

.maps is where marble stores the maps

Edit:
ls- la does not show the .maps folder

Hmm marble did corruped some folders on my previous N900. Solution was to rename the .maps folder. I was never able to delete anything because the filenames were strange with all kind of characters.
Maybe marble did something similar again but this time flooding myDocs till it broke.

I checked again. If I read it corretly I only use 122mb. So I don't think its maxed

Filesystem Size Used Available Use% Mounted on
/dev/mmcblk0p1 27.0G 122.3M 26.9G 0% /home/user/MyDocs

And again I stand corrected. Must have been too early

Bit only 122 MB used with some maps installed?
Sounds also strange. Especially as du already claimed 359MB found???

So as this is vFat and fsck is safe to be used on device you may try automatic fixing.
Or maybe better go with pichlo's approach...

I deleted all the maps as a try to fix the problem. Not sure why the folder is still present (du -hs error) and at the same time is not listed with ls -la

I have to wait till I get home since fsck does not run on the N900.

edit:
so format means I tap the n900 symbol an hold?
This will delete everyting in /home/user? Or at what level?