only change root-ro when tmpfs is used
only change root-ro when tmpfs is used

(cherry picked from commit 3396ac407091f16e8e91d5984421cac2c4922cdc)

MelvinTo/firewalla,MelvinTo/firewalla,MelvinTo/firewalla,firewalla/firewalla,MelvinTo/firewalla,firewalla/firewalla,firewalla/firewalla,MelvinTo/firewalla,firewalla/firewalla,firewalla/firewalla