mount remount android filesystem

1. adb shell
2. su -
3. mount | grep system

shell@android:/ $ mount | grep system
/dev/block/platform/msm_sdcc.1/by-name/system /system ext4 ro,relatime,data=ordered 0 0

4. mount -o rw,remount /dev/block/platform/msm_sdcc.1/by-name/system /system