mosfet current flow direction
No limitation.......Max current flow d>s = max current flow s>d
BUT.
The body diode is usually very low quality..it has slow reverse recovery........it can take ages to turn off so usually u dont risk ever turning it on.
Usually, if current could flow in the body diode, you put a fast, quality diode in parallel with the body diode so that the DREADED body diode hopefully doesn't get turned on.
and sometimes u try and stop the DREADFUL body diode from ever turning on by using a series diode in the drain connxion.....(cathode to drain)