Multiple mounts on same mount points

Wondering what could be the reason behind CIFS allowing multiple mounts
on same mount points while other Network File systems (say NFS) does
not.. For e.g.

   mount -t cifs //server/share /mnt/cifs
   mount -t cifs //server/share /mnt/cifs (also succeeds)

where one would expect an -EBUSY error during the second attempt.

Though I do not see any major issues, this behavior could be confusing
for users when they discover the mount is still present after umount
(because they mounted it twice unknowingly) or when they see multiple
mounts on same mount points.


Thanks,

-- 
Suresh Jayaraman