NFSD: Add nfsd4_encode_fattr4__false()

Add an encoding helper that encodes a single boolean "false" value.
Attributes that always return "false" can use this helper.

In a subsequent patch, this helper will be called from a bitmask
loop, so it is given a standardized synopsis.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4xdr.c

@@ -2954,6 +2954,12 @@ static __be32 nfsd4_encode_fattr4__true(struct xdr_stream *xdr,
 	return nfsd4_encode_bool(xdr, true);
 }
 
+static __be32 nfsd4_encode_fattr4__false(struct xdr_stream *xdr,
+					 const struct nfsd4_fattr_args *args)
+{
+	return nfsd4_encode_bool(xdr, false);
+}
+
 /*
  * Note: @fhp can be NULL; in this case, we might have to compose the filehandle
  * ourselves.
@@ -3150,10 +3156,9 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 			goto out;
 	}
 	if (bmval0 & FATTR4_WORD0_NAMED_ATTR) {
-		p = xdr_reserve_space(xdr, 4);
-		if (!p)
-			goto out_resource;
-		*p++ = cpu_to_be32(0);
+		status = nfsd4_encode_fattr4__false(xdr, &args);
+		if (status != nfs_ok)
+			goto out;
 	}
 	if (bmval0 & FATTR4_WORD0_FSID) {
 		p = xdr_reserve_space(xdr, 16);
@@ -3180,10 +3185,9 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 		}
 	}
 	if (bmval0 & FATTR4_WORD0_UNIQUE_HANDLES) {
-		p = xdr_reserve_space(xdr, 4);
-		if (!p)
-			goto out_resource;
-		*p++ = cpu_to_be32(0);
+		status = nfsd4_encode_fattr4__false(xdr, &args);
+		if (status != nfs_ok)
+			goto out;
 	}
 	if (bmval0 & FATTR4_WORD0_LEASE_TIME) {
 		p = xdr_reserve_space(xdr, 4);
@@ -3240,10 +3244,9 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 			goto out;
 	}
 	if (bmval0 & FATTR4_WORD0_CASE_INSENSITIVE) {
-		p = xdr_reserve_space(xdr, 4);
-		if (!p)
-			goto out_resource;
-		*p++ = cpu_to_be32(0);
+		status = nfsd4_encode_fattr4__false(xdr, &args);
+		if (status != nfs_ok)
+			goto out;
 	}
 	if (bmval0 & FATTR4_WORD0_CASE_PRESERVING) {
 		status = nfsd4_encode_fattr4__true(xdr, &args);