[Unionfs] Can't make branch read only

[Erez Zadok]

In message <200710251149.32474.herton at mandriva.com.br>, Herton Ronaldo Krzesinski writes:

> > Strange, now I tried a stock kernel and still get this behaviour, it's a
> > 2.6.22.9 kernel with just unionfs-2.1.7_for_2.6.22.10.diff.gz applied,
> > config attached.
> 
> Found some more time to debug this, and I discovered the following, with
> "mount -t unionfs -o remount,mode=/live/foo=ro none /live/union" for some 
> reason it fails as I told, but doing:
> "mount -o remount,mode=/live/foo=ro unionfs /live/union" I get the expected 
> behaviour. Note the slightly changes, I just don't use "-t" anymore and none 
> is replaced by unionfs. Can be a bug in our mount (from 
> util-linux-ng-2.13.0.1) or in kernel itself, I didn't found out yet (or is 
> just this way and we are using mount wrongly).

Can you run strace on mount(8) and see if it's producing different output?
I'm using /bin/mount from util-linux-2.13.  I'd say if utils-linux-ng
changed the behavior of "none" or "mode=" then this could cause a lot of
trouble to others as well.

Thanks,
Erez.