I have a dual-boot Windows 8.1 and Ubuntu 14.04 machine. Currently, I have one ext4 partition that is being used as my '/home' mount point in Ubuntu, and one NTFS partition that I am using to redirect 'My Documents' and such on Windows. This way both OS's are automatically using these partitions for file storage "under the hood".
My question is this: is there a reasonable way to make both OS's automatically use the same partition for file storage, without butting heads, and continuing this "under the hood" behavior? Preferably I would like to have this partition contain one folder named 'Ubuntu' and another folder named 'Windows', with the 'Ubuntu' folder acting as the mount point for '/home' and the 'Windows' folder containing my redirected profile folders, like in my current setup.
Is this possible? I'm guessing the format would have to be exFAT or something of the sort. Would there be any downsides (such as speed loss) from using this approach? And if this is not very reasonable, is there another setup that would give similar effects?
EDIT: Also, would it be reasonable to have a third folder on this partition for my Dropbox files (with each OS's dropbox program pointing to this same folder), so there is only one copy of my dropbox files on my disk?