Re: mount -ur doesn't work on NetBSD 5.0.2

[Michael Felke <mi.fe%web.de@localhost>]

Juergen Hannken-Illjes wrote:
> On Mon, May 10, 2010 at 12:46:34PM +0200, Michael Felke wrote:
> > Hello,
> >
> > we started to setup a new release of our netbsd server with NetBSD 5.0.2 
> > in stead of 4.0.1, as we have done last time.
> > Everything went well, until we tried to lock our root partion with 
> > "mount -ur /" again, after making it writeable with "mount -uw /".
> > Mount_ffs always complains that the operation is not supported, but we 
> > are using it since NetBSD 2.0, our first NetBSD based server. Forcing it 
> > work with "mount -urf /" doesn't work also.
> > We couldn't find something about a change of the ffs's option update 
> > behavior in the release notes of NetBSD 5.0.x.
> > Is this an indented change made to the GERNERIC kernel, then we need 
> > some help how to deactivate this new feature, or is it a bug, so must 
> > perhaps change back to 4.0.1.
> > The server is build on a i386 system and uses the raid device in level 1.
> >
> > sincerely
> > Michael Felke
>
> R/W to R/O downgrade has been disabled.  Please see
>
>   PR kern/30525 remounting ffs read-only (mount -ur) does not sync metadata
>
> Removing revision 1.373 of sys/kern/vfs_syscalls.c should re-enable the old
> (and risky) behaviour.

Thank you for the quick answer and the warning, we will take it seriously. 
But is this only a problem of ffs or does it arise with other file system, too?
Maybe it's save to use it with lfs as a root partition?

sincerely
Michael Felke