Find how to check and tune your ext filesystem here.
Easiest root password management is to not set it up at all and therefore not manage it.
How to manage emergency mode without root password can be read from here.
If you have to keep Bitlocker-encrypted windows and some Linux distro safely side by side on the same PC, check out this how to. It does not matter do you want Linux to be encrypted too, both options are also described.