diff --git a/Makefile.in b/Makefile.in
index 3f78399..996ae6c 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -41,7 +41,7 @@ PDATA_SOURCE=\
 	persistent-data/space-maps/disk.cc \
 	persistent-data/space-maps/recursive.cc \
 	persistent-data/space-maps/careful_alloc.cc
-PDATA_OBJECTS=$(subst .cc,.o,$(PDATA_SOURCE))
+#PDATA_OBJECTS=$(subst .cc,.o,$(PDATA_SOURCE))
 
 SOURCE=\
 	$(PDATA_SOURCE) \
@@ -56,6 +56,7 @@ SOURCE=\
 	thin-provisioning/restore_emitter.cc \
 	thin-provisioning/thin_pool.cc \
 	thin-provisioning/xml_format.cc
+PDATA_OBJECTS=$(subst .cc,.o,$(SOURCE))
 
 PROGRAM_SOURCE=\
 	cache/check.cc \
diff --git a/thin-provisioning/metadata.cc b/thin-provisioning/metadata.cc
index 224ac60..08e4b58 100644
--- a/thin-provisioning/metadata.cc
+++ b/thin-provisioning/metadata.cc
@@ -83,6 +83,7 @@ namespace {
 			::close(fd);
 			nr_blocks = div_down<block_address>(nr_blocks, MD_BLOCK_SIZE);
 		} else
+			// FIXME: needs a better message
 			throw runtime_error("bad path");
 
 		return nr_blocks;
diff --git a/unit-tests/Makefile.in b/unit-tests/Makefile.in
index 559360c..6dde371 100644
--- a/unit-tests/Makefile.in
+++ b/unit-tests/Makefile.in
@@ -50,6 +50,7 @@ TEST_SOURCE=\
 	unit-tests/cache_t.cc \
 	unit-tests/endian_t.cc \
 	unit-tests/space_map_t.cc \
+	unit-tests/thin_metadata_t.cc \
 	unit-tests/transaction_manager_t.cc
 
 TEST_OBJECTS=$(subst .cc,.gmo,$(TEST_SOURCE))
diff --git a/unit-tests/thin_metadata_t.cc b/unit-tests/thin_metadata_t.cc
new file mode 100644
index 0000000..a7c69b4
--- /dev/null
+++ b/unit-tests/thin_metadata_t.cc
@@ -0,0 +1,70 @@
+#include "gmock/gmock.h"
+
+#include "thin-provisioning/metadata.h"
+
+#include <errno.h>
+#include <linux/fs.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+using namespace std;
+using namespace persistent_data;
+using namespace testing;
+using namespace thin_provisioning;
+
+//----------------------------------------------------------------
+
+namespace {
+	void rm_f(string path) {
+		struct stat info;
+		int r = ::stat(path.c_str(), &info);
+
+		if (r) {
+			if (errno == ENOENT)
+				return;
+
+			else {
+				cerr << "errno == " << errno << endl;
+				throw runtime_error("stat failed");
+			}
+		}
+
+		if (!S_ISREG(info.st_mode))
+			throw runtime_error("path isn't a file");
+
+		::unlink(path.c_str());
+	}
+
+	// FIXME: duplication with block.tcc, factor out a file_utils unit
+	void create_sized_file(string const &path, uint64_t file_size) {
+		int fd = ::open(path.c_str(), O_CREAT | O_TRUNC | O_RDWR, 0666);
+		if (fd < 0)
+			throw runtime_error("open_file failed");
+
+		int r = ::lseek(fd, file_size - 1, SEEK_SET);
+		if (r < 0)
+			throw runtime_error("lseek failed");
+
+		char c = '\0';
+		r = ::write(fd, &c, 1);
+		if (r < 0)
+			throw runtime_error("::write failed");
+
+		if (r != 1)
+			throw runtime_error("insufficient bytes written");
+
+		::close(fd);
+	}
+}
+
+//----------------------------------------------------------------
+
+TEST(ThinMetadataTests, create)
+{
+	string path("./metadata.bin");
+	rm_f(path);
+	create_sized_file(path, 4096 * 1024);
+	metadata::ptr md(new metadata(path, metadata::CREATE, 128, 102400));
+}