On 2013-10-01 23:30, J. Bruce Fields wrote: > 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. I suggest moving the code in fs/nfsd/nfs4pnfsdlm.c to fs/dlm. Benny > > --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 > -- 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
