DAOS-6709 rsvc: xfer only attr size and fix tests (#4745)

This is a new way to fix extra data leak problem if
destination buffer is larger than real attr size.

To allow for only requested or attr exact size to be sent and
avoid packing by Mercury, each segment has to be sent as a
single bulk transfer instead as all being part of the same
bulk transfer and have Mercury do own management.

This allows to conform with original behaviour, so
no associated tests need to be modified anymore.

Signed-off-by: Bruno Faccini <bruno.faccini@intel.com>

src/rsvc/srv_common.c

@@ -176,6 +176,7 @@ ds_rsvc_get_attr(struct ds_rsvc *svc, struct rdb_tx *tx, rdb_path_t *path,
 	crt_bulk_t			 local_bulk;
 	daos_size_t			 bulk_size;
 	daos_size_t			 input_size;
+	daos_size_t			 local_offset, remote_offset;
 	d_iov_t			*iovs;
 	d_sg_list_t			 sgl;
 	void				*data;
@@ -259,7 +260,28 @@ ds_rsvc_get_attr(struct ds_rsvc *svc, struct rdb_tx *tx, rdb_path_t *path,
 		goto out_iovs;
 
 	rc = attr_bulk_transfer(rpc, CRT_BULK_PUT, local_bulk, remote_bulk,
-				0, key_length, bulk_size - key_length);
+				0, key_length, count * sizeof(*sizes));
+	if (rc != 0)
+		goto out_iovs;
+
+	local_offset = count * sizeof(*sizes);
+	remote_offset = key_length + count * sizeof(*sizes);
+
+	for (i = 1; i < sgl.sg_nr; i++) {
+		daos_size_t size;
+
+		size = min(sgl.sg_iovs[i].iov_len,
+				       sgl.sg_iovs[i].iov_buf_len);
+		rc = attr_bulk_transfer(rpc, CRT_BULK_PUT, local_bulk,
+					remote_bulk, local_offset,
+					remote_offset, size);
+		if (rc != 0)
+			goto out_iovs;
+
+		local_offset += sgl.sg_iovs[i].iov_buf_len;
+		remote_offset += sgl.sg_iovs[i].iov_buf_len;
+	}
+
 	crt_bulk_free(local_bulk);
 	if (rc != 0)
 		goto out_iovs;