Re: [RFC PATCH] NFS: Save 4 bytes when re-exporting

[Trond Myklebust]

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.

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx