Sorry, but there's a bit of a misconception happening here.
umask is NOT about rejecting any permissions. It is used
to define the default mode of a newly created file, and the
perms are XORed. E.g., a umask 022 will create a file with
644 permissions for you when you save a new file from an
The usage of umask in mount-entries in fstab is a whole
different story, read
(press n a couple of times)