If you have filesystem encryption, block-level encryption is probably unnecessary. Filesystem encryption is in most ways superior to block-level crypto.
Do you know of any software (maybe it's possible with Truecrypt?) to have full disk encryption with a hidden volume for Linux? I remember Truecrypt only worked on Windows with this feature. As Windows can auto-update your computer even when you disable it in the settings, I wouldn't want to use it.
The comparisons between filesystem-level vs. block-level encryption that I've encountered usually make a common distinction; namely that file metadata is still present when only applying fs-level encryption. What are some attributes of fs-level encryption that would make it a superior choice over block-level?
There are three huge advantages filesystems have over block devices when it comes to encryption:
1. They have storage flexibility, so they can allocate metadata to authenticators and nonces. The fact that sector-level crypto can't do this means that the "state of the art" in efficient sector crypto is essentially unauthenticated ECB mode.
2. They're message-aware, so they can apply authentication at meaningful boundaries; a block crypto device is essentially a simulated hard disk, and so it doesn't know where files begin and end.
3. Being message-aware, they can protect files at a better level of granularity than "all or nothing", which for instance is the security failure that made it so easy for the FBI to convict Ross Ulbricht for Silk Road.
A lot of concerns about filesystem crypto stem from the fact that filesystem crypto precedes sector-level crypto, and most of it was designed (or has designs tracing to) the 1990s. What people who don't spend a lot of time studying crypto should remember is that nobody knew how to encrypt anything in the 1990s. It was a unique and weird time, where there was a lot of demand and interest in crypto, but not enough knowledge to supply crypto effectively.
So we should be careful about judging filesystem crypto by the standards of the 1990s.