Thanks for the reply, Andy! So the write delegation can only reduce the unnecessary open/close and lock/locku. But if a client modify the same page for multiple times, e.g. editing the file in a editor, is there any optimization to prevent the client from sending the half-updated pages? Ideally only the final update need to be put on the wire. Thanks! best, Yudong On Wed, Aug 4, 2010 at 1:59 PM, Andy Adamson <andros@xxxxxxxxxx> wrote: > > On Aug 4, 2010, at 3:21 PM, Yudong Gao wrote: > >> Hi, >> >> I am not able to find the implementation of directory delegation, >> either. Similarly, the callback functions CB_NOTIFY is not >> implemented, either. I find that in preprocss_nfs41_op() in >> callback_xdr.c, whenever a CB_NOTIFY is encountered, an >> NFS4ERR_NOTSUPP is returned directly. > > CB_NOTIFY is not currently supported on the Linux NFS client. > >> >> Am I missing something? Or they are just not supported in the current version? >> >> Thanks a lot! >> >> best, >> >> Yudong >> >> On Mon, Aug 2, 2010 at 5:17 PM, Yudong Gao <stgyd@xxxxxxxxx> wrote: >>> Hi, >>> >>> I am looking at the delegation implementation in the source code of >>> NFS 4.1 in kernel 2.6.32.15. I can find the code for read delegation, >>> which is working and can serve the read requests locally. But I can >>> never find the code about write delegation, which is supposed to cache >>> the write update locally. I try to look at the functions including >>> nfs_writepage(s), nfs_file_flush() but none of them checks or uses the >>> write delegation. >>> >>> Is write delegation currently implemented in NFS 4.1? > > Write delegation is supported but I don't think write behavior changes - writes are still cached and flushed as without a write delegation. The write delegation does prevent open/close and lock/locku from being put on the wire. > > -->Andy > >>> >>> Thanks! >>> >>> best, >>> >>> Yudong >>> >> -- >> 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
