Permissions on your share are as follows:
Code:
# file: /mnt/Vol1/Shiva
# owner: root
# group: Everyone
owner@:rwxpDdaARWcCos:fd----:allow
group@:rwxpDdaARWcCos:fd----:allow
everyone@:r-x---a-R-c---:fd----:allow
The above output means that the LOCAL user "Root" has full control. The LOCAL (not AD) group "Everyone" has full control. Everyone else (as designated by well-known SID S-1-1-0) has read-only access. Your local group "Everyone" has no members. Ergo all your domain users have read-only access.
To fix this problem, in the webgui change the permissions of your dataset "Shiva" so that it is owned by Root (user) and "Domain Admins" (group). Then using a domain admin account, through the "computer management" MMC snap-in or through windows explorer navigating to \\freenas. Change the security settings of your share in the following ways:
1) Grant "Domain Users" read, write, and modify permissions
2) remove the "Everyone" ACE