On Sun, Sep 29, 2013 at 05:35:53AM -0700, Christoph Hellwig wrote: > On Sun, Sep 29, 2013 at 05:21:30AM -0700, Christoph Hellwig wrote: > > > Bruce - are you ok with moving the pnfs interface definitions to > > > include/linux/exportfs.h along with struct export_operations? > > > > > > In fact we can actually extend struct export_operations rather > > > than adding pnfs_export_operations... > > > > Yes, it probably should go into the export ops, although the actual > > method signatures might need to be made a litle less nfs-specific for > > that. > > I jsut took a brief look over the diff for the whole series in the git > tree and the old tree that still had block and exofs servers and have > revised my opinion a little bit: > > > - the should be a layout_type field in struct export_operations, > indicating that a filesystem support some sort of pnfs-like export. > - there should be a struct pnfs_operations, but it should be confined > to fs/nfsd: each layout can be a separate loadable module and gets > registered there. For the initial file layout that module is > self-contained, but for e.g. block or objects it would have > call into the filesystem through export_ops, although way lower level > than the NFS XDR level, e.g. for block there would be one of to get > the extent map, and one to allocate an extent. That sounds OK to me. My (possibly faulty) memory of how the xdr-encoding-in-the-fs came about: I think people weren't willing to commit to any reasonable upper limit on the size of the layout. So they originally considered something more like readdir that would loop over extents and pass them to a callback for encoding. But xdr isn't complicated so you could instead give the filesystem a simple library of xdr encoders to call. But it sounds like that's not exactly what got implemented. And maybe nobody actually has such big layouts. > This way we alsod avoid the dependcy on nfsd in the filesystems that the > cureent version introduces. Ugh--thanks for catching that. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
