Re: [PATCH/RFC nfs-utils] exports.man: improve documentation of 'nohide' and 'crossmnt'

["J. Bruce Fields" <bfields@fieldses.org>]

On Wed, Feb 18, 2015 at 12:41:01PM +1100, NeilBrown wrote:
> On Mon, 16 Feb 2015 15:17:51 -0500 bfields@fieldses.org (J. Bruce Fields)
> wrote:
> 
> > On Mon, Feb 16, 2015 at 12:21:07PM +1100, NeilBrown wrote:
> > > 
> > > 
> > > - note that 'nohide' is irrelevant for NFSv4
> > > - note that children on a 'crossmnt' filesystem cannot be unexported
> > > - note that 'nocrossmnt' is a valid option, but probably not useful.
> > > 
> > > Signed-off-by: NeilBrown <neilb@suse.de>
> > > 
> > > ---
> > > 
> > > I wonder if we should add a new option, e.g. "noaccess" so that children
> > > of a "crossmnt" filesystem can be hidden.  The  kernel wouldn't need to
> > > know about this.  It would just tell mountd to refuse to export that
> > > filesystem even if the parent was "crossmnt".
> > > ??
> > 
> > Seems logical enough, but I can't recall seeing requests for it, and
> > the options here already seem complicated enough.
> 
> I haven't seem requests myself.  Just rumours of 'nohide' not working with
> NFSv4, which seems to suggest that someone wants something like that.
> But I cannot find a clear source.
> 
> Maybe:
> 
> http://ubuntuforums.org/showthread.php?t=2152643
> http://ubuntuforums.org/showthread.php?t=1603881
> 
> 
> > 
> > In theory something like that could also be done with namespaces.  (So,
> > run mountd in a separate mount namespace that lacks those children.)
> 
> Do any of the NFS man pages need to be updated to say something about
> namespaces?

Maybe just a note in the rpc.mountd man page that export paths are all
with respect to the mount namespace rpc.mountd is running in?

--b.