I think, this bug is much more related to filesystem itself than btrfs-tools. Because as you can see, df -h gives me the same result. That is all what i want to add to this bug from my side at this moment. Thank you for your time spent trying to sort it out. I just wasn't sure which package is responsible to this bug so I decided to set it as it is bug in btrfs-tools. I am sorry if it is wrong way.
