[Samba] dfree command...

[Robert S. Irrgang]

Hello,

I've a little problem with samba 4.5.x on debian stretch.
I've shared a folder with a mounted partition and a sub-mounted partition.

mount /dev/sdb1 /opt/smb
mount /dev/sdc1 /opt/smb/subfolder

But on windows only the free size of /dev/sdb1 is reported.
So I try to use the "dfree command" directive to give back the full free 
size of all sub-mounted devices.
But it seems samba is not using the shell script.

Any idea what's wrong? Is this disabled on samba 4.5.x?

Thank you for help!