[Samba] File permissions

[Oscar A. Valdez]

I'm trying to understand how file permissions are handled by smbmount.
I've setuid root both smbmnt and smbumount, so that regular users can
mount and unmount samba shares. Pertinent options in /etc/fstab are
users,rw,fmask=770

Rights are as follows:

 r-- r-- r--	:file permissions on the Samba server
 rwx rwx ---	:fmask specified in /etc/fstab
 rwx r-x r-x	:root user's umask
 rwx rwx r-x	:regular users' umask
drwx r-x r-x	:permissions on mount point before mount
drwx rwx ---	:permissions on mount point after mount
 r-x r-x ---	:mounted file permissions

I would like to understand why I end up with 550 on the mounted files,
instead of 440 (which are the file permissions on the server) or 770
(which are the rights specified by the fmask option).
-- 
Oscar A. Valdez