USB Storage

I have a Beagle Bone Black and can access it through the USB port on my Windows 10 machine. I see that /dev/mmcblk0p1 is the ‘drive’ Windows sees I can mount the on the Linux side and see the same files that I see on my PC. However, if I change a file on either the PC or the Linux side, the change is not seen on the other end. In other words if I have file foo.txt and change it on the PC, the Linux version of the file remains unchanged. I seem to be missing something. Any help?