As fbe pointed "umask" isn't a valid option for many linux filesystems.
If the optionless mount suggested doesn't work it's unlikely anyone will be able to help further without knowing which "linux filesystem" it actually is. There are many and not all are installed/supported out of the box (i.e. you have to install them).
To find out which you have, try:
Once you have that, read the "Filesystem Independent Mount Options" section of the man page for mount and the "Mount options for ..." for the relevant filesystem.
You can get the docc by
Given your umask option, I'm guessing you want to force full read/write permissions to everyone on that partition all the time, regardless of who created or owns the file/directory.
With the linux/unix security model that's not going to be possible. You can do a recursive chmod a+rwx on the mount point after mounting but any new files or directories will have the default permissions of the person who created them along with that person as the owner and their primary group.
Read up on the linux/unix security model for more info.
The umask option exists for some non-linux filesystem that have no concept of owner, group, and world permissions (or owner and group for that matter) e.g. FAT and some that have some of those concepts but not in a way that can be easily mapped.
Arguing with strangers on the internet since 1993.