Re: [RFD] readonly/read-write semantics

[Ingo Oeser <ingo.oeser@informatik.tu-chemnitz.de>]

On Sat, Sep 01, 2001 at 12:23:05AM -0400, Alexander Viro wrote:
> > 2) I'd like to see a readonly mount state defined as "the filesystem will
> > not change.  Period."  Not for system calls in progress, not for cache
> > synchronization, not to set an "unmounted" flag, not for writes that are
> > queued in the device driver or device.  (That last one may stretch
> > feasability, but it's a worthy goal anyway).
> 
> It doesn't work.  Think of r/o mounting of remote filesystem.  Do you
> suggest that it should make it impossible to change from other clients?

It's sufficient for local file systems. Or see it this way: The
machine, that mounted it r/o will NOT write to it until it is
mounted r/w again.

I also like the "kill/finish all outstanding writes" idea (kill
or finish should depend on the MNT_FORCE option). Once we've
implemented it, forcible unmount becomes trivial ;-)

Forcible unmount is high on the wish list of several admins I
know.

Regards

Ingo Oeser