diff --git a/thin-provisioning/thin_generate_metadata.cc b/thin-provisioning/thin_generate_metadata.cc
index 7a7c990..f7127cc 100644
--- a/thin-provisioning/thin_generate_metadata.cc
+++ b/thin-provisioning/thin_generate_metadata.cc
@@ -17,6 +17,7 @@
 // <http://www.gnu.org/licenses/>.
 
 #include "base/output_file_requirements.h"
+#include "persistent-data/file_utils.h"
 #include "thin-provisioning/commands.h"
 #include "thin-provisioning/metadata.h"
 #include "version.h"
@@ -34,16 +35,132 @@ using namespace thin_provisioning;
 
 namespace {
 	struct flags {
+		enum metadata_operations {
+			METADATA_OP_NONE,
+			METADATA_OP_FORMAT,
+			METADATA_OP_OPEN,
+			METADATA_OP_CREATE_THIN,
+			METADATA_OP_LAST
+		};
+
 		flags()
-			: data_block_size(128),
+			: op(METADATA_OP_NONE),
+			  data_block_size(128),
 			  nr_data_blocks(10240)
 		{
 		}
 
-		block_address data_block_size;
+		bool check_conformance();
+
+		metadata_operations op;
+		sector_t data_block_size;
 		block_address nr_data_blocks;
+		optional<uint64_t> dev_id;
 		optional<string> output;
 	};
+
+	// FIXME: modulize the conditions
+	bool flags::check_conformance() {
+		if (op == METADATA_OP_NONE || op >= METADATA_OP_LAST) {
+			cerr << "Invalid operation." << endl;
+			return false;
+		}
+
+		if (!output) {
+			cerr << "No output file provided." << endl;
+			return false;
+		} else
+			check_output_file_requirements(*output);
+
+		if (op == METADATA_OP_CREATE_THIN && !dev_id) {
+			cerr << "no device id provided." << endl;
+			return false;
+		}
+
+		return true;
+	}
+
+	//--------------------------------
+
+	single_mapping_tree::ptr new_mapping_tree(metadata::ptr md) {
+		return single_mapping_tree::ptr(
+			new single_mapping_tree(*md->tm_,
+						mapping_tree_detail::block_time_ref_counter(md->data_sm_)));
+	}
+
+	bool is_device_exists(metadata::ptr md, uint64_t dev_id) {
+		uint64_t key[1] = {dev_id};
+
+		device_tree::maybe_value v1 = md->details_->lookup(key);
+		if (v1)
+			return true;
+
+		dev_tree::maybe_value v2 = md->mappings_top_level_->lookup(key);
+		if (v2)
+			return true;
+
+		return false;
+	}
+
+	//--------------------------------
+
+	metadata::ptr format_metadata(block_manager::ptr bm,
+				      sector_t data_block_size,
+				      block_address nr_data_blocks) {
+		metadata::ptr md(new metadata(bm,
+					      metadata::CREATE,
+					      data_block_size,
+					      nr_data_blocks));
+		md->commit();
+		return md;
+	}
+
+	metadata::ptr open_metadata(block_manager::ptr bm) {
+		metadata::ptr md(new metadata(bm, true));
+		return md;
+	}
+
+	void create_thin(metadata::ptr md, uint64_t dev_id) {
+		uint64_t key[1] = {dev_id};
+
+		if (is_device_exists(md, dev_id))
+			throw runtime_error("device already exists");
+
+		device_tree_detail::device_details details;
+		details.transaction_id_ = md->sb_.trans_id_;
+		details.creation_time_ = md->sb_.time_;
+		details.snapshotted_time_ = details.creation_time_;
+		md->details_->insert(key, details);
+
+		single_mapping_tree::ptr subtree = new_mapping_tree(md);
+		md->mappings_top_level_->insert(key, subtree->get_root());
+		md->mappings_->set_root(md->mappings_top_level_->get_root()); // FIXME: ugly
+
+		md->commit();
+	}
+
+	metadata::ptr open_or_format_metadata(block_manager::ptr bm, flags const &fs) {
+
+		if (fs.op == flags::METADATA_OP_FORMAT)
+			return format_metadata(bm, fs.data_block_size, fs.nr_data_blocks);
+		else
+			return open_metadata(bm);
+	}
+
+	int generate_metadata(flags const &fs) {
+		block_manager::ptr bm = open_bm(*fs.output, block_manager::READ_WRITE);
+		metadata::ptr md = open_or_format_metadata(bm, fs);
+
+		switch (fs.op) {
+		case flags::METADATA_OP_CREATE_THIN:
+			create_thin(md, *fs.dev_id);
+			break;
+		default:
+			break;
+		}
+
+		return 0;
+	}
 }
 
 //----------------------------------------------------------------
@@ -74,8 +191,12 @@ thin_generate_metadata_cmd::run(int argc, char **argv)
 	const struct option longopts[] = {
 		{ "help", no_argument, NULL, 'h' },
 		{ "output", required_argument, NULL, 'o' },
+		{ "format", no_argument, NULL, 1 },
+		{ "open", no_argument, NULL, 2 },
+		{ "create-thin", no_argument, NULL, 3 },
 		{ "data-block-size", required_argument, NULL, 101 },
 		{ "nr-data-blocks", required_argument, NULL, 102 },
+		{ "dev-id", required_argument, NULL, 301 },
 		{ "version", no_argument, NULL, 'V' },
 		{ NULL, no_argument, NULL, 0 }
 	};
@@ -90,6 +211,18 @@ thin_generate_metadata_cmd::run(int argc, char **argv)
 			fs.output = optarg;
 			break;
 
+		case 1:
+			fs.op = flags::METADATA_OP_FORMAT;
+			break;
+
+		case 2:
+			fs.op = flags::METADATA_OP_OPEN;
+			break;
+
+		case 3:
+			fs.op = flags::METADATA_OP_CREATE_THIN;
+			break;
+
 		case 101:
 			fs.data_block_size = parse_uint64(optarg, "data block size");
 			break;
@@ -98,6 +231,10 @@ thin_generate_metadata_cmd::run(int argc, char **argv)
 			fs.nr_data_blocks = parse_uint64(optarg, "nr data blocks");
 			break;
 
+		case 301:
+			fs.dev_id = parse_uint64(optarg, "dev id");
+			break;
+
 		case 'V':
 			cout << THIN_PROVISIONING_TOOLS_VERSION << endl;
 			return 0;
@@ -108,14 +245,12 @@ thin_generate_metadata_cmd::run(int argc, char **argv)
 		}
 	}
 
-	if (!fs.output) {
-		cerr << "No output file provided.\n\n";
+	if (!fs.check_conformance()) {
 		usage(cerr);
 		return 1;
-	} else
-		check_output_file_requirements(*fs.output);
+	}
 
-	return 0;
+	return generate_metadata(fs);
 }
 
 //----------------------------------------------------------------