So..... Dropbox has over the last few months been warning about requiring an Ext4 file system to be able to use the linux (Ubuntu) client.. in effect requiring you to use an unencrypted drive (you better be using one..) to store your dropbox content.
Well here is a way to get around it.. (A.k.A. FU Dropbox)
**Create an Ext4 file system on top of your encrypted partition just for drop box.. **
Instructions Below.. (adjust as necessary)
OLDDBLOCATION=~/Dropbox
echo "Stop Dropbox now, press enter when ready"
mv $OLDDBLOCATION $OLDDBLOCATION.old
dd if=/dev/zero of=~/DROPBOX bs=1024 count=2200000
mkfs.ext4 ~/DROPBOX
mkdir $OLDDBLOCATION
sudo mount -t ext4 ~/DROPBOX $OLDDBLOCATION
cd $OLDDBLOCATION
(cd ../$OLDDBLOCATION.old;tar cvf - *) | tar cvf -
echo "Start Dropbox now. note you may have to remove and re-auth the machine for the warnings to go away, press enter when ready"
all done.. just make sure to add the mount to the fstab file
/home/(user)/DROPBOX /home/(user)/Dropbox ext4 defaults 0 2