How to extend /dev/root?

Hello! I installed LEDE on a 2 GB SD card and am running it on Ras Pi 3 B, while it seems that root doesn't make use of all the space. I tried to extend root by extending /dev/mmcblk0p2, or ls -n and resize2fs but root just got a bit larger. How can I extend root to the rest space so that I could be able to install more packages? Thanks!

Disk /dev/mmcblk0: 1.9 GiB, 1967128576 bytes, 3842048 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x5452574f

Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 * 8192 49151 40960 20M c W95 FAT32 (LBA)
/dev/mmcblk0p2 57344 3842047 3784704 1.8G 83 Linux

Filesystem 1K-blocks Used Available Use% Mounted on
/dev/root 387032 155300 223868 41% /
tmpfs 476332 80 476252 0% /tmp
/dev/mmcblk0p1 20422 8924 11498 44% /boot
tmpfs 512 0 512 0% /dev

SD card images of openwrt/lede cant know your exact flash card size and that's why they come with small partitions.
You must resize /dev/mmcblk0p2 and then resize file system on it.
The easiest way - insert card into linux PC and use gparted.