Virtually all versions of frinas I see a strange policy developers to assign permissions to folders and files in a shared folder for Windows machines (smb) on a local network.
The default value of true - to inherit the access rights that is not quite the right decision.
Therefore it is necessary to set the value - not to inherit permissions, and to make these lines in the Auxiliary parameters
create mask = 0664
directory mask = 0775
For some Trojans such action is fatalWhen add next strings into smb settings ( all for shares )
domain master = yes
name resolve order = wins lmhosts hosts bcast
os level = 99
preferred master = yes
wins support = yes
And in Windows add to wins adress wins server as freenas server
Also samba and FTP on FreeNAS not allow symlinks. For repair this problem add PostInit script
mount_nullfs /mnt/data/public /mnt/data/user1/public
Samba begin to work great