[Cluster-devel] Re: GFS2: Allow all meta/normal mount combinations

[Steven Whitehouse]

Hi,

On Mon, 2009-06-08 at 12:12 -0400, Christoph Hellwig wrote:
> On Fri, Jun 05, 2009 at 03:17:43PM +0100, Steven Whitehouse wrote:
> > > This is pretty ugly.  Even if this is how the old gfs2meta filesystem
> > > worked I would prefer to only allow it if mounted as type gfs2meta, not
> > > for normal gfs2 mount and gradually phase it out.
> > > 
> > Which bit is ugly? We need to be able to do this to be sure that we can
> > get a metafs which exactly matches the "normal" fs without races I
> > think. Thats a requirement of the userland tools, unfortunately.
> 
> Well, the block device from /proc/self/mounts really is a unique
> key you can get.
> 
> If you really insist on using a path to a file make sure that normal
> mounts only take the block device, and meta mounts only take the file.
> 
> But even with that it's not a very clear interface.
> 

Yes, ok. I think I'll drop this patch for now then. Using the block
device does seem to work ok, and we'd need to update the tools to for
the "file" based method.

We can update the tools to pass a device I think by parsing /proc/mounts
for the path of the "real" filesystem and then using the device entry to
pass to mount. That should solve the problem without needing to add this
patch,

Steve.