Re: [PATCH 2/3] NFSv42: Don't drop NFS_INO_INVALID_CHANGE if we hold a delegation

[Trond Myklebust <trondmy@hammerspace.com>]

On Tue, 2021-11-16 at 09:12 -0500, Benjamin Coddington wrote:
> On 16 Nov 2021, at 9:03, Trond Myklebust wrote:
> > No, we really shouldn't need to care what the server thinks or
> > does.
> > The client is authoritative for the change attribute while it holds
> > a
> > delegation, not the server.
> 
> My understanding of the intention of the code (which I had to sort of
> put
> together from historical patches in this area) is that we want to see
> ctime,
> mtime, and block size updates after copy/clone even if we hold a
> delegation,
> but without NFS_INO_INVALID_CHANGE, the client won't update those
> attributes.
> 
> If that's not necessary, we can drop this patch.
> 

We will still see the ctime/mtime/block size updates even if
NFS_INO_INVALID_CHANGE is not set. Those attributes' cache status are
tracked separately through their own NFS_INO_INVALID_* bits.

That said, there really is no reason why we shouldn't treat the copy
and clone code exactly the same way we would treat a regular write.
Perhaps we can fix up the arguments of nfs_writeback_update_inode() so
that it can be called here?

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