NFS: Add support for sending GDD_GETATTR

I add this to the existing GETATTR compound as an option extra step that
we can send if the "dir_deleg" flag is set to 'true'. Actually enabling
this value will happen in a later patch.

Signed-off-by: Anna Schumaker <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/nfs4xdr.c

···
 				XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + 5)
 #define encode_reclaim_complete_maxsz	(op_encode_hdr_maxsz + 4)
 #define decode_reclaim_complete_maxsz	(op_decode_hdr_maxsz + 4)
+#define encode_get_dir_deleg_maxsz (op_encode_hdr_maxsz + \
+				    4 /* gdda_signal_deleg_avail */ + \
+				    8 /* gdda_notification_types */ + \
+				    nfstime4_maxsz /* gdda_child_attr_delay */ + \
+				    nfstime4_maxsz /* gdda_dir_attr_delay */ + \
+				    nfs4_fattr_bitmap_maxsz /* gdda_child_attributes */ + \
+				    nfs4_fattr_bitmap_maxsz /* gdda_dir_attributes */)
+#define decode_get_dir_deleg_maxsz (op_decode_hdr_maxsz + \
+				    4 /* gddrnf_status */ + \
+				    encode_verifier_maxsz /* gddr_cookieverf */ + \
+				    encode_stateid_maxsz /* gddr_stateid */ + \
+				    8 /* gddr_notification */ + \
+				    nfs4_fattr_maxsz /* gddr_child_attributes */ + \
+				    nfs4_fattr_maxsz /* gddr_dir_attributes */)
 #define encode_getdeviceinfo_maxsz (op_encode_hdr_maxsz + \
 				XDR_QUADLEN(NFS4_DEVICEID4_SIZE) + \
 				1 /* layout type */ + \
···
 #else /* CONFIG_NFS_V4_1 */
 #define encode_sequence_maxsz	0
 #define decode_sequence_maxsz	0
+#define encode_get_dir_deleg_maxsz 0
+#define decode_get_dir_deleg_maxsz 0
 #define encode_layoutreturn_maxsz 0
 #define decode_layoutreturn_maxsz 0
 #define encode_layoutget_maxsz	0
···
 #define NFS4_enc_getattr_sz	(compound_encode_hdr_maxsz + \
 				encode_sequence_maxsz + \
 				encode_putfh_maxsz + \
+				encode_get_dir_deleg_maxsz + \
 				encode_getattr_maxsz + \
 				encode_renew_maxsz)
 #define NFS4_dec_getattr_sz	(compound_decode_hdr_maxsz + \
 				decode_sequence_maxsz + \
 				decode_putfh_maxsz + \
+				decode_get_dir_deleg_maxsz + \
 				decode_getattr_maxsz + \
 				decode_renew_maxsz)
 #define NFS4_enc_lookup_sz	(compound_encode_hdr_maxsz + \
···
 
 #ifdef CONFIG_NFS_V4_1
 static void
+encode_get_dir_delegation(struct xdr_stream *xdr, struct compound_hdr *hdr)
+{
+	struct timespec64 ts = { 0, 0 };
+	u32 notifications[1] = { 0 };
+	u32 attributes[1] = { 0 };
+	__be32 *p;
+
+	encode_op_hdr(xdr, OP_GET_DIR_DELEGATION, decode_get_dir_deleg_maxsz, hdr);
+
+	/* We don't handle CB_RECALLABLE_OBJ_AVAIL yet. */
+	xdr_stream_encode_bool(xdr, false);
+
+	xdr_encode_bitmap4(xdr, notifications, ARRAY_SIZE(notifications));
+
+	/* Request no delay on attribute updates */
+	p = reserve_space(xdr, 12 + 12);
+	p = xdr_encode_nfstime4(p, &ts);
+	xdr_encode_nfstime4(p, &ts);
+
+	/* Requested child attributes */
+	xdr_encode_bitmap4(xdr, attributes, ARRAY_SIZE(attributes));
+
+	/* Requested dir attributes */
+	xdr_encode_bitmap4(xdr, attributes, ARRAY_SIZE(attributes));
+}
+
+static void
 encode_getdeviceinfo(struct xdr_stream *xdr,
 		     const struct nfs4_getdeviceinfo_args *args,
 		     struct compound_hdr *hdr)
···
 	encode_nfs4_stateid(xdr, &args->stateid);
 }
 #else
+static inline void
+encode_get_dir_delegation(struct xdr_stream *xdr, struct compound_hdr *hdr)
+{
+}
+
 static inline void
 encode_layoutreturn(struct xdr_stream *xdr,
 		    const struct nfs4_layoutreturn_args *args,
···
 	encode_compound_hdr(xdr, req, &hdr);
 	encode_sequence(xdr, &args->seq_args, &hdr);
 	encode_putfh(xdr, args->fh, &hdr);
+	if (args->get_dir_deleg)
+		encode_get_dir_delegation(xdr, &hdr);
 	encode_getfattr(xdr, args->bitmask, &hdr);
 	encode_nops(&hdr);
 }
···
 	return decode_stateid(xdr, stateid);
 }
 
+static int decode_get_dir_delegation(struct xdr_stream *xdr,
+				     struct nfs4_getattr_res *res)
+{
+	struct nfs4_gdd_res *gdd_res = res->gdd_res;
+	nfs4_verifier cookieverf;
+	u32 bitmap[1];
+	int status;
+
+	status = decode_op_hdr(xdr, OP_GET_DIR_DELEGATION);
+	if (status)
+		return status;
+
+	if (xdr_stream_decode_u32(xdr, &gdd_res->status))
+		return -EIO;
+
+	if (gdd_res->status == GDD4_UNAVAIL)
+		return xdr_inline_decode(xdr, 4) ? 0 : -EIO;
+
+	status = decode_verifier(xdr, &cookieverf);
+	if (status)
+		return status;
+
+	status = decode_delegation_stateid(xdr, &gdd_res->deleg);
+	if (status)
+		return status;
+
+	/* Decode supported notification types. */
+	status = decode_bitmap4(xdr, bitmap, ARRAY_SIZE(bitmap));
+	if (status < 0)
+		return status;
+
+	/* Decode supported child attributes. */
+	status = decode_bitmap4(xdr, bitmap, ARRAY_SIZE(bitmap));
+	if (status < 0)
+		return status;
+
+	/* Decode supported attributes. */
+	status = decode_bitmap4(xdr, bitmap, ARRAY_SIZE(bitmap));
+	if (status < 0)
+		return status;
+	return 0;
+}
+
 static int decode_getdeviceinfo(struct xdr_stream *xdr,
 				struct nfs4_getdeviceinfo_res *res)
 {
···
 	return res->status;
 }
 #else
+static int decode_get_dir_delegation(struct xdr_stream *xdr,
+				     struct nfs4_getattr_res *res)
+{
+	return 0;
+}
+
 static inline
 int decode_layoutreturn(struct xdr_stream *xdr,
 			       struct nfs4_layoutreturn_res *res)
···
 	status = decode_putfh(xdr);
 	if (status)
 		goto out;
+	if (res->gdd_res) {
+		status = decode_get_dir_delegation(xdr, res);
+		if (status)
+			goto out;
+	}
 	status = decode_getfattr(xdr, res->fattr, res->server);
 out:
 	return status;

include/linux/nfs_xdr.h

···
 	struct nfs4_sequence_args	seq_args;
 	const struct nfs_fh *		fh;
 	const u32 *			bitmask;
+	bool				get_dir_deleg;
+};
+
+struct nfs4_gdd_res {
+	u32				status;
+	nfs4_stateid			deleg;
 };
 
 struct nfs4_getattr_res {
 	struct nfs4_sequence_res	seq_res;
 	const struct nfs_server *	server;
 	struct nfs_fattr *		fattr;
+	struct nfs4_gdd_res *		gdd_res;
 };
 
 struct nfs4_link_arg {