After upgrading the OpenWRT in my router to a new version I lose every time my DLNA and SMB shares. To remind me for the next time here are the commands to get the shares up and running in a minute. The configurations are there after all, so only the installation of the needed packages is needed.
opkg update && opkg install block-mount e2fsprogs kmod-fs-ext4 kmod-usb-storage kmod-usb2 kmod-usb3 samba36-server luci-app-samba minidlna luci-app-minidlna
/etc/init.d/minidlna start && /etc/init.d/minidlna enable