In order for the host device to be remounted ro it is also necessary that any loopdevice it contains is also ro, I am not aware of any way to change the ro/rw status of loopdevices after they are created, save maybe "blockdev --setro" (thanks to Colin Watson for the tip!).
In order for the host device to be remounted ro it is also necessary that any loopdevice it contains is also ro, I am not aware of any way to change the ro/rw status of loopdevices after they are created, save maybe "blockdev --setro" (thanks to Colin Watson for the tip!).