samba - May 2016 - trying to use a loop device connected to a folder /test created with dd and mounted to /test but access denied unless i set chmod o+rw to the path but securiy setting always access denied

i make a image file connected to /dev/loop0 formated as ext4 partition
and connect it
losetup /dev/loop0 /root/disk.img

then make format the loop drive with
mkfs.ext4 -o rw,usrquota,grpquota /dev/loop0 /disk
connected it to /test

the only way to write there other users except root is setting with
chmod o+w /test

from windows 7 using samba 4 i can write to folder but i cannot set
security setting getting always access denied when i am setting
security settings on the share

what is wrong

thank you

sarantopoulos nikos