Re: NFS and non-blkdev-backed FS?

[Christoph Hellwig <hch@infradead.org>]

On Fri, Aug 15, 2008 at 10:18:12AM -0400, Trond Myklebust wrote:
> On Fri, 2008-08-15 at 14:59 +0100, David Woodhouse wrote:
> > On Fri, 2008-08-15 at 11:55 +0300, Artem Bityutskiy wrote:
> > > UBIFS (as e.g. XFS) has a 16-byte UUID in superblock which is
> > > supposed to uniquely identify the file-system. I'd like to use
> > > this UUID as NFS FSID instead, however, I failed to find how
> > > to do this. Any hints how could I do this?
> > 
> > By adding a 'get_fsid()' method to the export_ops structure...
> > 
> 
> If the uuid can be found by libuuid, then it will automatically be used
> as the default identifier by rpc.mount (man 5 exports). There should be
> no need for a new export_ops method.

We'll need it anyway, for exports not starting at the root of the
volume, and we'll need a method to be called when exporting a filesystem
to reject it if the filehandle couldn't fit into the space available
for the given nfs protocol version.