[Unionfs] Re: Exporting a union with NFS4 ?

[Erez Zadok]

In message <47B0B998.5020601 at ccs.nrl.navy.mil>, Jesse I Pollard writes:
> pascal at pabr.org wrote:
> > Jesse I Pollard wrote:
> >> pascal at pabr.org wrote:
> >>> So would it be possible to export unions over NFS4 if we initialized
> >>> sb->s_export_op in unionfs_read_super(), along the lines of what was
> >>> done in unionfs-1.4 ?
> >>>
> >>> Does anyone have a patch which does that ?  I do not mind if it only
> >>> supports lower filesystems with small inode numbers or if branches
> >>> cannot be added/removed afterward.
> >> nope. been there, tried that.
> >
> > Thanks for the feedback...  But did you discover that there are
> > fundamental incompatibilities, or only that it did not work as
> > easily as expected ?
> 
> There were fundamental incompatibilities. The base requirement that
> was laid out, is two required functions: fh_to_dentry, and fh_to_parent.
> These are defined in the 1.x series, are insufficient for the 2.x.
> 
> The ODF version has a complete new file: export.c, which has all of
> the export_ops functions defined (5 functions + some supporting
> functions). I know there are plans to merge the ODF release into
> the regular 2.x release, and maybe there could be an option for
> the ODF portion included.

We try to keep the ODF and regular unionfs releases in sync, so that we
won't need to import any code from the ODF branch to the other.  It should
be a drop-in replacement, where all fixes/features that exist in the non-odf
branch, also exist in the other.

Erez.