mount -u -r drops nosuid ?

[Oliver Fromme]

Dag-Erling Smørgrav <des at des.no> wrote:
 > Oliver Fromme <olli at lurza.secnetix.de> writes:
 > > Dag-Erling Smørgrav <des at des.no> wrote:
 > > > Oliver Fromme <olli at lurza.secnetix.de> writes:
 > > > > Because you didn't specify it.  When updating the options
 > > > > on a filesystem, only the options that you specify are
 > > > > used.  Otherwise there would be no way to remove options
 > > > > like nosuid.
 > > > uh, yes there would: -o suid
 > > Then it should be documented in the mount(8) manpage.
 > 
 > All mount options can be negated by adding the "no" prefix, or
 > removing it if it is already there.

Yes, I verified that by experimenting, after you mentioned
that "-o suid" would work.

But:  That behaviour is _not_ documented.  Or maybe I just
suffer from partial blindness.  I searched the mount(8)
manual page up and down in both RELENG_4 and RELENG_6.
There is no mentioning of the "no" prefix at all.  In fact,
it documents "async" and "noasync" separately, which lead
me to the (wrong) conclusion that the "no" prefix would
only work for those options for which it is explicitely
documented.

Shall I submit a doc PR?

Best regards
   Oliver

-- 
Oliver Fromme,  secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
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