----- Ursprüngliche Mail ----- > Von: "richard" <richard@xxxxxx> > ----- Ursprüngliche Mail ----- >> Von: "Trond Myklebust" <trondmy@xxxxxxxxxxxxxxx> >> On Sun, 2021-12-12 at 22:00 +0100, Richard Weinberger wrote: >>> When re-exporting, the whole struct nfs_fh is embedded in the new >>> fhandle. >>> But we need only nfs_fh->data[], nfs_fh->size is not needed. >>> So skip fs_fh->size and save a full word (4 bytes). >>> The downside is the extra memcpy() in nfs_fh_to_dentry(). >>> >>> Signed-off-by: Richard Weinberger <richard@xxxxxx> >>> --- >>> While investigating into improving NFS re-export I noticed that >>> we can already save 4 bytes of overhead. >>> I don't think we need to embedd the full struct nfs_fh and >>> can skip ->size. >>> >> >> NACK. This will break existing running clients. Any code to change the >> filehandle format must be accompanied with code to detect and service >> filehandles that are presented in the old format. > > One possible way to distinguish between old and new formats > is looking at the length of the data. > 2 * XDR_UNIT = new format (without ->size). > 3 * XDR_UNIT = old format. Never mind. This won't work. Thanks, //richard
