thodg/libgit2

diff --git a/include/git2/sys/refdb_backend.h b/include/git2/sys/refdb_backend.h
index 9cf5073..d5611d0 100644
--- a/include/git2/sys/refdb_backend.h
+++ b/include/git2/sys/refdb_backend.h
@@ -93,11 +93,13 @@ struct git_refdb_backend {
 	 * must provide this function.
 	 */
 	int (*write)(git_refdb_backend *backend,
-		const git_reference *ref, int force);
+		     const git_reference *ref, int force,
+		     const char *message);
 
 	int (*rename)(
 		git_reference **out, git_refdb_backend *backend,
-		const char *old_name, const char *new_name, int force);
+		const char *old_name, const char *new_name, int force,
+		const char *message);
 
 	/**
 	 * Deletes the given reference from the refdb.  A refdb implementation
diff --git a/src/refdb.c b/src/refdb.c
index adb5880..8f002eb 100644
--- a/src/refdb.c
+++ b/src/refdb.c
@@ -167,14 +167,14 @@ void git_refdb_iterator_free(git_reference_iterator *iter)
 	iter->free(iter);
 }
 
-int git_refdb_write(git_refdb *db, git_reference *ref, int force)
+int git_refdb_write(git_refdb *db, git_reference *ref, int force, const char *message)
 {
 	assert(db && db->backend);
 
 	GIT_REFCOUNT_INC(db);
 	ref->db = db;
 
-	return db->backend->write(db->backend, ref, force);
+	return db->backend->write(db->backend, ref, force, message);
 }
 
 int git_refdb_rename(
@@ -182,12 +182,13 @@ int git_refdb_rename(
 	git_refdb *db,
 	const char *old_name,
 	const char *new_name,
-	int force)
+	int force,
+	const char *message)
 {
 	int error;
 
 	assert(db && db->backend);
-	error = db->backend->rename(out, db->backend, old_name, new_name, force);
+	error = db->backend->rename(out, db->backend, old_name, new_name, force, message);
 	if (error < 0)
 		return error;
 
diff --git a/src/refdb.h b/src/refdb.h
index 0ee60d9..4dea20b 100644
--- a/src/refdb.h
+++ b/src/refdb.h
@@ -33,14 +33,15 @@ int git_refdb_rename(
 	git_refdb *db,
 	const char *old_name,
 	const char *new_name,
-	int force);
+	int force,
+	const char *message);
 
 int git_refdb_iterator(git_reference_iterator **out, git_refdb *db, const char *glob);
 int git_refdb_iterator_next(git_reference **out, git_reference_iterator *iter);
 int git_refdb_iterator_next_name(const char **out, git_reference_iterator *iter);
 void git_refdb_iterator_free(git_reference_iterator *iter);
 
-int git_refdb_write(git_refdb *refdb, git_reference *ref, int force);
+int git_refdb_write(git_refdb *refdb, git_reference *ref, int force, const char *message);
 int git_refdb_delete(git_refdb *refdb, const char *ref_name);
 
 int git_refdb_reflog_read(git_reflog **out, git_refdb *db,  const char *name);
diff --git a/src/refdb_fs.c b/src/refdb_fs.c
index 62d5c10..6eb6ec4 100644
--- a/src/refdb_fs.c
+++ b/src/refdb_fs.c
@@ -910,7 +910,8 @@ fail:
 static int refdb_fs_backend__write(
 	git_refdb_backend *_backend,
 	const git_reference *ref,
-	int force)
+	int force,
+	const char *message)
 {
 	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
 	int error;
@@ -974,7 +975,8 @@ static int refdb_fs_backend__rename(
 	git_refdb_backend *_backend,
 	const char *old_name,
 	const char *new_name,
-	int force)
+	int force,
+	const char *message)
 {
 	refdb_fs_backend *backend = (refdb_fs_backend *)_backend;
 	git_reference *old, *new;
@@ -1264,6 +1266,32 @@ static int serialize_reflog_entry(
 	return git_buf_oom(buf);
 }
 
+static int lock_reflog(git_filebuf *file, refdb_fs_backend *backend, const char *refname)
+{
+	git_repository *repo;
+	git_buf log_path = GIT_BUF_INIT;
+	int error;
+
+	repo = backend->repo;
+
+	if (retrieve_reflog_path(&log_path, repo, refname) < 0)
+		return -1;
+
+	if (!git_path_isfile(git_buf_cstr(&log_path))) {
+		giterr_set(GITERR_INVALID,
+			"Log file for reference '%s' doesn't exist.", refname);
+		error = -1;
+		goto cleanup;
+	}
+
+	error = git_filebuf_open(file, git_buf_cstr(&log_path), 0, GIT_REFLOG_FILE_MODE);
+
+cleanup:
+	git_buf_free(&log_path);
+
+	return error;
+}
+
 static int refdb_reflog_fs__write(git_refdb_backend *_backend, git_reflog *reflog)
 {
 	int error = -1;
@@ -1271,7 +1299,6 @@ static int refdb_reflog_fs__write(git_refdb_backend *_backend, git_reflog *reflo
 	git_reflog_entry *entry;
 	git_repository *repo;
 	refdb_fs_backend *backend;
-	git_buf log_path = GIT_BUF_INIT;
 	git_buf log = GIT_BUF_INIT;
 	git_filebuf fbuf = GIT_FILEBUF_INIT;
 
@@ -1280,18 +1307,9 @@ static int refdb_reflog_fs__write(git_refdb_backend *_backend, git_reflog *reflo
 	backend = (refdb_fs_backend *) _backend;
 	repo = backend->repo;
 
-	if (retrieve_reflog_path(&log_path, repo, reflog->ref_name) < 0)
+	if ((error = lock_reflog(&fbuf, backend, reflog->ref_name)) < 0)
 		return -1;
 
-	if (!git_path_isfile(git_buf_cstr(&log_path))) {
-		giterr_set(GITERR_INVALID,
-			"Log file for reference '%s' doesn't exist.", reflog->ref_name);
-		goto cleanup;
-	}
-
-	if ((error = git_filebuf_open(&fbuf, git_buf_cstr(&log_path), 0, GIT_REFLOG_FILE_MODE)) < 0)
-		goto cleanup;
-
 	git_vector_foreach(&reflog->entries, i, entry) {
 		if (serialize_reflog_entry(&log, &(entry->oid_old), &(entry->oid_cur), entry->committer, entry->msg) < 0)
 			goto cleanup;
@@ -1308,7 +1326,7 @@ cleanup:
 
 success:
 	git_buf_free(&log);
-	git_buf_free(&log_path);
+
 	return error;
 }
 
diff --git a/src/refs.c b/src/refs.c
index d3d072c..dbbdda0 100644
--- a/src/refs.c
+++ b/src/refs.c
@@ -396,7 +396,7 @@ static int reference__create(
 
 	GITERR_CHECK_ALLOC(ref);
 
-	if ((error = git_refdb_write(refdb, ref, force)) < 0) {
+	if ((error = git_refdb_write(refdb, ref, force, log_message)) < 0) {
 		git_reference_free(ref);
 		return error;
 	}
@@ -579,7 +579,7 @@ int git_reference_rename(
 
 	should_head_be_updated = (error > 0);
 
-	if ((error = git_refdb_rename(out, ref->db, ref->name, new_name, force)) < 0)
+	if ((error = git_refdb_rename(out, ref->db, ref->name, new_name, force, NULL)) < 0)
 		return error;
 
 	/* Update HEAD it was poiting to the reference being renamed. */