nfsd: update mtime/ctime on COPY in presence of delegated attributes

nfsd: update mtime/ctime on COPY in presence of delegated attributes

When delegated attributes are given on open, the file is opened with
NOCMTIME and modifying operations do not update mtime/ctime as to not get
out-of-sync with the client's delegated view. However, for COPY operation,
the server should update its view of mtime/ctime and reflect that in any
GETATTR queries.

Fixes: e5e9b24ab8fa ("nfsd: freeze c/mtime updates with outstanding WRITE_ATTRS delegation")
Cc: stable@vger.kernel.org
Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>