Continue using dropbox on btrfs... etc after Nov 2018

dropbox-on-btrfs.txt

btrfs filesystem label /cloud CLOUD

fallocate -l 40G /cloud/Dropbox.loop
losetup /dev/loop0 /cloud/Dropbox.loop
mkfs.ext4 /dev/loop0
mkdir $HOME/DropboxLoop
mount -t ext4 /dev/loop0 $HOME/DropboxLoop
chown $USER:$USER $HOME/DropboxLoop

chown -R $USER:$USER $HOME/Dropbox $HOME/.dropbox
chattr -R -i $HOME/Dropbox # fix/remove any files/problems here
chmod -R u+rw $HOME/Dropbox $HOME/.dropbox

<Right-Click-Dropbox-Icon>->Preferences->Sync->Dropbox folder location->Move
  to: $HOME/DropboxLoop
ln -s $HOME/DropboxLoop/Dropbox $Home/Dropbox

In fstab:
/dev/loop0      <HOME>/DropboxLoop       ext4    loop,users,noauto       0 0

Start dropbox with:
mount /dev/loop0
chown $USER:$USER $HOME/DropboxLoop
dropbox

Above mainly thanks to ang-p at: https://www.reddit.com/r/linux/comments/9siamu/psa_dropbox_ext4_limitation_workaround/