Miklos Szeredi wrote:
>> Some mount options are never passed to the kernel, and thus can't appear 
>> in /proc/mounts.  Examples include user, users, and _netdev for NFS.
> 
> These options control *who* may mount and *when* to mount.  They are
> not a property of the mount itself and are not added to /etc/mtab.
> 
> There's a "user=ID" option that is added to /etc/mtab in case of user
> mounts.  This identifies the owner of the mount, so that it can be
> unmounted by that user.  There are patches in -mm that enable the
> kernel to store this info.
> 
> Do you have other examples in mind?

[no]quota comes to mind; also auto, [no]owner, [no]group, and 
quiet/loud, but these may fall into the same category you mention above.

Aside: It's a confusing artifact of the mount CLI that these options 
control who/when but are passed to the mount command in the same way the 
other options are.