diff --git a/gio/gvdb/gvdb-builder.c b/gio/gvdb/gvdb-builder.c
index 2383e6002..b8ecbe3d7 100644
--- a/gio/gvdb/gvdb-builder.c
+++ b/gio/gvdb/gvdb-builder.c
@@ -339,9 +339,11 @@ file_builder_allocate_for_hash (FileBuilder            *fb,
 #undef chunk
 
   memset (*bloom_filter, 0, n_bloom_words * sizeof (guint32_le));
+  memset (*hash_buckets, 0, n_buckets * sizeof (guint32_le));
+  memset (*hash_items, 0, n_items * sizeof (struct gvdb_hash_item));
 
   /* NOTE - the code to actually fill in the bloom filter here is missing.
-   * Patches welcome! 
+   * Patches welcome!
    *
    * http://en.wikipedia.org/wiki/Bloom_filter
    * http://0pointer.de/blog/projects/bloom.html
@@ -450,6 +452,13 @@ file_builder_new (gboolean byteswap)
   return builder;
 }
 
+static void
+file_builder_free (FileBuilder *fb)
+{
+  g_queue_free (fb->chunks);
+  g_slice_free (FileBuilder, fb);
+}
+
 static GString *
 file_builder_serialise (FileBuilder          *fb,
                         struct gvdb_pointer   root)
@@ -494,9 +503,6 @@ file_builder_serialise (FileBuilder          *fb,
       g_slice_free (FileChunk, chunk);
     }
 
-  g_queue_free (fb->chunks);
-  g_slice_free (FileBuilder, fb);
-
   return result;
 }
 
@@ -511,12 +517,118 @@ gvdb_table_write_contents (GHashTable   *table,
   FileBuilder *fb;
   GString *str;
 
+  g_return_val_if_fail (table != NULL, FALSE);
+  g_return_val_if_fail (filename != NULL, FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
   fb = file_builder_new (byteswap);
   file_builder_add_hash (fb, table, &root);
   str = file_builder_serialise (fb, root);
+  file_builder_free (fb);
 
   status = g_file_set_contents (filename, str->str, str->len, error);
   g_string_free (str, TRUE);
 
   return status;
 }
+
+typedef struct {
+  GBytes *contents;  /* (owned) */
+  GFile  *file;      /* (owned) */
+} WriteContentsData;
+
+static WriteContentsData *
+write_contents_data_new (GBytes *contents,
+                         GFile  *file)
+{
+  WriteContentsData *data;
+
+  data = g_slice_new (WriteContentsData);
+  data->contents = g_bytes_ref (contents);
+  data->file = g_object_ref (file);
+
+  return data;
+}
+
+static void
+write_contents_data_free (WriteContentsData *data)
+{
+  g_bytes_unref (data->contents);
+  g_object_unref (data->file);
+  g_slice_free (WriteContentsData, data);
+}
+
+static void
+replace_contents_cb (GObject      *source_object,
+                     GAsyncResult *result,
+                     gpointer      user_data)
+{
+  GTask *task = user_data;
+  WriteContentsData *data = g_task_get_task_data (task);
+  GError *error = NULL;
+
+  g_return_if_fail (g_task_get_source_tag (task) == gvdb_table_write_contents_async);
+
+  if (!g_file_replace_contents_finish (data->file, result, NULL, &error))
+    g_task_return_error (task, g_steal_pointer (&error));
+  else
+    g_task_return_boolean (task, TRUE);
+
+  g_object_unref (task);
+}
+
+void
+gvdb_table_write_contents_async (GHashTable          *table,
+                                 const gchar         *filename,
+                                 gboolean             byteswap,
+                                 GCancellable        *cancellable,
+                                 GAsyncReadyCallback  callback,
+                                 gpointer             user_data)
+{
+  struct gvdb_pointer root;
+  FileBuilder *fb;
+  WriteContentsData *data;
+  GString *str;
+  GBytes *bytes;
+  GFile *file;
+  GTask *task;
+
+  g_return_if_fail (table != NULL);
+  g_return_if_fail (filename != NULL);
+  g_return_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable));
+
+  fb = file_builder_new (byteswap);
+  file_builder_add_hash (fb, table, &root);
+  str = file_builder_serialise (fb, root);
+  bytes = g_string_free_to_bytes (str);
+  file_builder_free (fb);
+
+  file = g_file_new_for_path (filename);
+  data = write_contents_data_new (bytes, file);
+
+  task = g_task_new (NULL, cancellable, callback, user_data);
+  g_task_set_task_data (task, data, (GDestroyNotify)write_contents_data_free);
+  g_task_set_source_tag (task, gvdb_table_write_contents_async);
+
+  g_file_replace_contents_async (file,
+                                 g_bytes_get_data (bytes, NULL),
+                                 g_bytes_get_size (bytes),
+                                 NULL, FALSE,
+                                 G_FILE_CREATE_PRIVATE,
+                                 cancellable, replace_contents_cb, g_steal_pointer (&task));
+
+  g_bytes_unref (bytes);
+  g_object_unref (file);
+}
+
+gboolean
+gvdb_table_write_contents_finish (GHashTable    *table,
+                                  GAsyncResult  *result,
+                                  GError       **error)
+{
+  g_return_val_if_fail (table != NULL, FALSE);
+  g_return_val_if_fail (g_task_is_valid (result, NULL), FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  return g_task_propagate_boolean (G_TASK (result), error);
+}
diff --git a/gio/gvdb/gvdb-builder.h b/gio/gvdb/gvdb-builder.h
index b4815f0d0..30757d039 100644
--- a/gio/gvdb/gvdb-builder.h
+++ b/gio/gvdb/gvdb-builder.h
@@ -51,5 +51,16 @@ gboolean                gvdb_table_write_contents                       (GHashTa
                                                                          const gchar    *filename,
                                                                          gboolean        byteswap,
                                                                          GError        **error);
+G_GNUC_INTERNAL
+void                    gvdb_table_write_contents_async                 (GHashTable          *table,
+                                                                         const gchar         *filename,
+                                                                         gboolean             byteswap,
+                                                                         GCancellable        *cancellable,
+                                                                         GAsyncReadyCallback  callback,
+                                                                         gpointer             user_data);
+G_GNUC_INTERNAL
+gboolean                gvdb_table_write_contents_finish                (GHashTable          *table,
+                                                                         GAsyncResult        *result,
+                                                                         GError             **error);
 
 #endif /* __gvdb_builder_h__ */
diff --git a/gio/gvdb/gvdb-reader.c b/gio/gvdb/gvdb-reader.c
index 83ad2ac19..6bc4c6f36 100644
--- a/gio/gvdb/gvdb-reader.c
+++ b/gio/gvdb/gvdb-reader.c
@@ -351,10 +351,10 @@ gvdb_table_get_names (GvdbTable *table,
                       gsize     *length)
 {
   gchar **names;
-  gint n_names;
-  gint filled;
-  gint total;
-  gint i;
+  guint n_names;
+  guint filled;
+  guint total;
+  guint i;
 
   /* We generally proceed by iterating over the list of items in the
    * hash table (in order of appearance) recording them into an array.