NFSv4.2: Don't send mode again in post-EXCLUSIVE4_1 SETATTR with umask

Now that we have umask support, we shouldn't re-send the mode in a SETATTR
following an exclusive CREATE, or we risk having the same problem fixed in
commit 5334c5bdac92 ("NFS: Send attributes in OPEN request for
NFS4_CREATE_EXCLUSIVE4_1"), which is that files with S_ISGID will have that
bit stripped away.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Fixes: dff25ddb4808 ("nfs: add support for the umask attribute")
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4proc.c

@@ -2589,7 +2589,8 @@ static inline void nfs4_exclusive_attrset(struct nfs4_opendata *opendata,
 
 	/* Except MODE, it seems harmless of setting twice. */
 	if (opendata->o_arg.createmode != NFS4_CREATE_EXCLUSIVE &&
-		attrset[1] & FATTR4_WORD1_MODE)
+		(attrset[1] & FATTR4_WORD1_MODE ||
+		 attrset[2] & FATTR4_WORD2_MODE_UMASK))
 		sattr->ia_valid &= ~ATTR_MODE;
 
 	if (attrset[2] & FATTR4_WORD2_SECURITY_LABEL)