Unable to mount docker folder into host using docker-compose
If you use CentOS 7 (as I have ). You may have SELinux turned on by default.check https://www.rootusers.com/how-to-enable-or-disable-selinux-in-centos-rhel-7/
or mount like this: 

  volumes:
   - ./database:/var/lib/mysql:Z
   - ./_conf/mariadb.cnf:/etc/mysql/my.cnf:Z
   - ./logs:/var/log/mysql:Z