----- 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. What do you think? Thanks, //richard
