Re: [PATCH 3/6 linux-next] fs/affs: make affs exportable

[bfields@fieldses.org (J. Bruce Fields)]

On Wed, Jan 04, 2017 at 06:53:31AM +0100, Fabian Frederick wrote:
> 
> 
> > On 03 January 2017 at 23:29 Al Viro <viro@ZenIV.linux.org.uk> wrote:
> >
> >
> > On Tue, Jan 03, 2017 at 10:30:39PM +0100, Fabian Frederick wrote:
> > > Add standard functions making AFFS work with NFS.
> > >
> > > Functions based on ext4 implementation.
> > > Tested on loop device.
> >
> > How the hell is that supposed to work with cold dcache?  You don't have
> > ->get_parent() there at all...
> >
> > There *IS* a reference to parent directory in those suckers - not the same
> > kind as in normal unix filesystems (".." is not a directory entry there -
> > it's all fake), but it's doable.  be32_to_cpu(AFFS_TAIL(sb, bh)->parent)
> > would be the inumber you need, where bh is the inode block of directory.
> >
> > So it can be done, but not in this form.  NAK for the time being...
> 
> I worked on that function declared optional in
> Documentation/filesystems/nfs/Exporting
> but was unable to test it.

If we're going to reject patches that don't implement get_parent (and I
think we should), then we should replace "optional but strongly
recommended" there by just "mandatory".  Any objections?

--b.