Have to take ownership at a groups of subfolders (not to much folders) and delete, and for "File too long" errors, firstly have to take ownership and then moved in upper position to delete. I managed to delete all folders, but it take time because the are a lot of subfolders
If you have to takeownership of the mount folder to delete it/clean it up, there is something going very wrong, the unmount /discard option or mountpoint cleanup command should take care of it (can also be done after rebooting first).