settings: cache keyfile databases for "timestamps" and "seen-bssids"

Only read the keyfile databases once and cache them for the remainder of
the program.

- this avoids the overhead of opening the file over and over again.

- it also avoids the data changing without us expecting it. The state
  files are internal and we don't support changing it outside of
  NetworkManager. So in the base case we read the same data over
  and over. In the worst case, we read different data but are not
  interested in handling the changes.

- only write the file when the content changes or before exiting
  (normally).

- better log what is happening.

- our state files tend to grow as we don't garbage collect old entries.
  Keeping this all in memory might be problematic. However, the right
  solution for this is that we come up with some form of garbage
  collection so that the state files are reaonsably small to begin with.

4 files changed, 261 insertions, 204 deletions

diff --git a/src/settings/nm-settings-connection.c b/src/settings/nm-settings-connection.c
index 3fdaa59814..3bb30cbe57 100644
--- a/src/settings/nm-settings-connection.c
+++ b/src/settings/nm-settings-connection.c
@@ -25,6 +25,7 @@
 
 #include "c-list/src/c-list.h"
 
+#include "nm-glib-aux/nm-keyfile-aux.h"
 #include "nm-libnm-core-intern/nm-common-macros.h"
 #include "nm-config.h"
 #include "nm-config-data.h"
@@ -38,9 +39,6 @@
 #include "nm-core-internal.h"
 #include "nm-audit-manager.h"
 
-#define SETTINGS_TIMESTAMPS_FILE  NMSTATEDIR "/timestamps"
-#define SETTINGS_SEEN_BSSIDS_FILE NMSTATEDIR "/seen-bssids"
-
 #define AUTOCONNECT_RETRIES_UNSET        -2
 #define AUTOCONNECT_RETRIES_FOREVER      -1
 #define AUTOCONNECT_RESET_RETRIES_TIMER 300
@@ -86,6 +84,9 @@ static guint signals[LAST_SIGNAL] = { 0 };
 
 typedef struct _NMSettingsConnectionPrivate {
 
+	NMKeyFileDB *kf_db_timestamps;
+	NMKeyFileDB *kf_db_seen_bssids;
+
 	NMAgentManager *agent_mgr;
 	NMSessionMonitor *session_monitor;
 	gulong session_changed_id;
@@ -658,42 +659,6 @@ out:
 	return TRUE;
 }
 
-static void
-remove_entry_from_db (NMSettingsConnection *self, const char* db_name)
-{
-	GKeyFile *key_file;
-	const char *db_file;
-
-	if (strcmp (db_name, "timestamps") == 0)
-		db_file = SETTINGS_TIMESTAMPS_FILE;
-	else if (strcmp (db_name, "seen-bssids") == 0)
-		db_file = SETTINGS_SEEN_BSSIDS_FILE;
-	else
-		return;
-
-	key_file = g_key_file_new ();
-	if (g_key_file_load_from_file (key_file, db_file, G_KEY_FILE_KEEP_COMMENTS, NULL)) {
-		const char *connection_uuid;
-		char *data;
-		gsize len;
-		GError *error = NULL;
-
-		connection_uuid = nm_settings_connection_get_uuid (self);
-
-		g_key_file_remove_key (key_file, db_name, connection_uuid, NULL);
-		data = g_key_file_to_data (key_file, &len, &error);
-		if (data) {
-			g_file_set_contents (db_file, data, len, &error);
-			g_free (data);
-		}
-		if (error) {
-			_LOGW ("error writing %s file '%s': %s", db_name, db_file, error->message);
-			g_error_free (error);
-		}
-	}
-	g_key_file_free (key_file);
-}
-
 gboolean
 nm_settings_connection_delete (NMSettingsConnection *self,
                                GError **error)
@@ -701,6 +666,7 @@ nm_settings_connection_delete (NMSettingsConnection *self,
 	gs_unref_object NMSettingsConnection *self_keep_alive = NULL;
 	NMSettingsConnectionPrivate *priv = NM_SETTINGS_CONNECTION_GET_PRIVATE (self);
 	NMConnection *for_agents;
+	const char *connection_uuid;
 
 	g_return_val_if_fail (NM_IS_SETTINGS_CONNECTION (self), FALSE);
 
@@ -719,11 +685,13 @@ nm_settings_connection_delete (NMSettingsConnection *self,
 	                                 for_agents);
 	g_object_unref (for_agents);
 
-	/* Remove timestamp from timestamps database file */
-	remove_entry_from_db (self, "timestamps");
+	connection_uuid = nm_settings_connection_get_uuid (self);
+
+	if (priv->kf_db_timestamps)
+		nm_key_file_db_remove_key (priv->kf_db_timestamps, connection_uuid);
 
-	/* Remove connection from seen-bssids database file */
-	remove_entry_from_db (self, "seen-bssids");
+	if (priv->kf_db_seen_bssids)
+		nm_key_file_db_remove_key (priv->kf_db_seen_bssids, connection_uuid);
 
 	nm_settings_connection_signal_remove (self);
 	return TRUE;
@@ -2338,11 +2306,13 @@ gboolean
 nm_settings_connection_get_timestamp (NMSettingsConnection *self,
                                       guint64 *out_timestamp)
 {
+	NMSettingsConnectionPrivate *priv;
+
 	g_return_val_if_fail (NM_IS_SETTINGS_CONNECTION (self), FALSE);
 
-	if (out_timestamp)
-		*out_timestamp = NM_SETTINGS_CONNECTION_GET_PRIVATE (self)->timestamp;
-	return NM_SETTINGS_CONNECTION_GET_PRIVATE (self)->timestamp_set;
+	priv = NM_SETTINGS_CONNECTION_GET_PRIVATE (self);
+	NM_SET_OUT (out_timestamp, priv->timestamp);
+	return priv->timestamp_set;
 }
 
 /**
@@ -2350,56 +2320,31 @@ nm_settings_connection_get_timestamp (NMSettingsConnection *self,
  * @self: the #NMSettingsConnection
  * @timestamp: timestamp to set into the connection and to store into
  * the timestamps database
- * @flush_to_disk: if %TRUE, commit timestamp update to persistent storage
  *
  * Updates the connection and timestamps database with the provided timestamp.
  **/
 void
 nm_settings_connection_update_timestamp (NMSettingsConnection *self,
-                                         guint64 timestamp,
-                                         gboolean flush_to_disk)
+                                         guint64 timestamp)
 {
 	NMSettingsConnectionPrivate *priv = NM_SETTINGS_CONNECTION_GET_PRIVATE (self);
 	const char *connection_uuid;
-	GKeyFile *timestamps_file;
-	char *data, *tmp;
-	gsize len;
-	GError *error = NULL;
+	char sbuf[60];
 
 	g_return_if_fail (NM_IS_SETTINGS_CONNECTION (self));
 
-	/* Update timestamp in private storage */
 	priv->timestamp = timestamp;
 	priv->timestamp_set = TRUE;
 
-	if (flush_to_disk == FALSE)
-		return;
-	if (nm_config_get_configure_and_quit (nm_config_get ()) == NM_CONFIG_CONFIGURE_AND_QUIT_INITRD)
+	if (!priv->kf_db_timestamps)
 		return;
 
-	/* Save timestamp to timestamps database file */
-	timestamps_file = g_key_file_new ();
-	if (!g_key_file_load_from_file (timestamps_file, SETTINGS_TIMESTAMPS_FILE, G_KEY_FILE_KEEP_COMMENTS, &error)) {
-		if (!g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
-			_LOGW ("error parsing timestamps file '%s': %s", SETTINGS_TIMESTAMPS_FILE, error->message);
-		g_clear_error (&error);
-	}
-
 	connection_uuid = nm_settings_connection_get_uuid (self);
-	tmp = g_strdup_printf ("%" G_GUINT64_FORMAT, timestamp);
-	g_key_file_set_value (timestamps_file, "timestamps", connection_uuid, tmp);
-	g_free (tmp);
-
-	data = g_key_file_to_data (timestamps_file, &len, &error);
-	if (data) {
-		g_file_set_contents (SETTINGS_TIMESTAMPS_FILE, data, len, &error);
-		g_free (data);
+	if (connection_uuid) {
+		nm_key_file_db_set_value (priv->kf_db_timestamps,
+		                          connection_uuid,
+		                          nm_sprintf_buf (sbuf, "%" G_GUINT64_FORMAT, timestamp));
 	}
-	if (error) {
-		_LOGW ("error saving timestamp to file '%s': %s", SETTINGS_TIMESTAMPS_FILE, error->message);
-		g_error_free (error);
-	}
-	g_key_file_free (timestamps_file);
 }
 
 /**
@@ -2410,38 +2355,79 @@ nm_settings_connection_update_timestamp (NMSettingsConnection *self,
  * stores it into the connection private data.
  **/
 void
-nm_settings_connection_read_and_fill_timestamp (NMSettingsConnection *self)
+nm_settings_connection_register_kf_dbs (NMSettingsConnection *self,
+                                        NMKeyFileDB *kf_db_timestamps,
+                                        NMKeyFileDB *kf_db_seen_bssids)
 {
-	NMSettingsConnectionPrivate *priv = NM_SETTINGS_CONNECTION_GET_PRIVATE (self);
-	gs_unref_keyfile GKeyFile *timestamps_file = NULL;
-	gs_free_error GError *error = NULL;
-	gs_free char *tmp_str = NULL;
+	NMSettingsConnectionPrivate *priv;
 	const char *connection_uuid;
-	gint64 timestamp;
 
 	g_return_if_fail (NM_IS_SETTINGS_CONNECTION (self));
+	g_return_if_fail (kf_db_timestamps);
+	g_return_if_fail (kf_db_seen_bssids);
 
-	timestamps_file = g_key_file_new ();
-	if (!g_key_file_load_from_file (timestamps_file, SETTINGS_TIMESTAMPS_FILE, G_KEY_FILE_KEEP_COMMENTS, &error)) {
-		_LOGD ("failed to read connection timestamp: %s", error->message);
-		return;
-	}
+	priv = NM_SETTINGS_CONNECTION_GET_PRIVATE (self);
 
 	connection_uuid = nm_settings_connection_get_uuid (self);
-	tmp_str = g_key_file_get_value (timestamps_file, "timestamps", connection_uuid, &error);
-	if (!tmp_str) {
-		_LOGD ("failed to read connection timestamp: %s", error->message);
-		return;
-	}
 
-	timestamp = _nm_utils_ascii_str_to_int64 (tmp_str, 10, 0, G_MAXINT64, -1);
-	if (timestamp < 0) {
-		_LOGD ("failed to read connection timestamp: %s", "invalid number");
-		return;
+	if (priv->kf_db_timestamps != kf_db_timestamps) {
+		gs_free char *tmp_str = NULL;
+		guint64 timestamp;
+
+		nm_key_file_db_unref (priv->kf_db_timestamps);
+		priv->kf_db_timestamps = nm_key_file_db_ref (kf_db_timestamps);
+
+		tmp_str = nm_key_file_db_get_value (priv->kf_db_timestamps, connection_uuid);
+
+		timestamp = _nm_utils_ascii_str_to_uint64 (tmp_str, 10, 0, G_MAXUINT64, G_MAXUINT64);
+		if (timestamp != G_MAXUINT64) {
+			priv->timestamp = timestamp;
+			priv->timestamp_set = TRUE;
+			_LOGT ("read timestamp %"G_GUINT64_FORMAT" from keyfile database \"%s\"",
+			       timestamp, nm_key_file_db_get_filename (priv->kf_db_timestamps));
+		} else
+			_LOGT ("no timestamp from keyfile database \"%s\"",
+			       nm_key_file_db_get_filename (priv->kf_db_timestamps));
 	}
 
-	priv->timestamp = timestamp;
-	priv->timestamp_set = TRUE;
+	if (priv->kf_db_seen_bssids != kf_db_seen_bssids) {
+		gs_strfreev char **tmp_strv = NULL;
+		gsize i, len;
+
+		nm_key_file_db_unref (priv->kf_db_seen_bssids);
+		priv->kf_db_seen_bssids = nm_key_file_db_ref (kf_db_seen_bssids);
+
+		tmp_strv = nm_key_file_db_get_string_list (priv->kf_db_seen_bssids, connection_uuid, &len);
+
+		if (tmp_strv) {
+			_LOGT ("read %zu seen-bssids from keyfile database \"%s\"",
+			       NM_PTRARRAY_LEN (tmp_strv),
+			       nm_key_file_db_get_filename (priv->kf_db_seen_bssids));
+			g_hash_table_remove_all (priv->seen_bssids);
+			for (i = len; i > 0; )
+				g_hash_table_add (priv->seen_bssids, g_steal_pointer (&tmp_strv[--i]));
+		} else {
+			NMSettingWireless *s_wifi;
+
+			_LOGT ("no seen-bssids from keyfile database \"%s\"",
+			       nm_key_file_db_get_filename (priv->kf_db_seen_bssids));
+
+			/* If this connection didn't have an entry in the seen-bssids database,
+			 * maybe this is the first time we've read it in, so populate the
+			 * seen-bssids list from the deprecated seen-bssids property of the
+			 * wifi setting.
+			 */
+			s_wifi = nm_connection_get_setting_wireless (nm_settings_connection_get_connection (self));
+			if (s_wifi) {
+				len = nm_setting_wireless_get_num_seen_bssids (s_wifi);
+				for (i = 0; i < len; i++) {
+					const char *bssid = nm_setting_wireless_get_seen_bssid (s_wifi, i);
+
+					g_hash_table_add (priv->seen_bssids, g_strdup (bssid));
+				}
+			}
+		}
+	}
 }
 
 /**
@@ -2504,108 +2490,26 @@ nm_settings_connection_add_seen_bssid (NMSettingsConnection *self,
                                        const char *seen_bssid)
 {
 	NMSettingsConnectionPrivate *priv = NM_SETTINGS_CONNECTION_GET_PRIVATE (self);
+	gs_free const char **strv = NULL;
 	const char *connection_uuid;
-	GKeyFile *seen_bssids_file;
-	char *data, *bssid_str;
-	const char **list;
-	gsize len;
-	GError *error = NULL;
-	GHashTableIter iter;
-	guint n;
 
 	g_return_if_fail (seen_bssid != NULL);
 
-	if (g_hash_table_lookup (priv->seen_bssids, seen_bssid))
-		return;  /* Already in the list */
-
-	/* Add the new BSSID; let the hash take ownership of the allocated BSSID string */
-	bssid_str = g_strdup (seen_bssid);
-	g_hash_table_insert (priv->seen_bssids, bssid_str, bssid_str);
+	g_hash_table_add (priv->seen_bssids, g_strdup (seen_bssid));
 
-	/* Build up a list of all the BSSIDs in string form */
-	n = 0;
-	list = g_malloc0 (g_hash_table_size (priv->seen_bssids) * sizeof (char *));
-	g_hash_table_iter_init (&iter, priv->seen_bssids);
-	while (g_hash_table_iter_next (&iter, NULL, (gpointer) &bssid_str))
-		list[n++] = bssid_str;
-
-	/* Save BSSID to seen-bssids file */
-	seen_bssids_file = g_key_file_new ();
-	g_key_file_set_list_separator (seen_bssids_file, ',');
-	if (!g_key_file_load_from_file (seen_bssids_file, SETTINGS_SEEN_BSSIDS_FILE, G_KEY_FILE_KEEP_COMMENTS, &error)) {
-		if (!g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NOENT)) {
-			_LOGW ("error parsing seen-bssids file '%s': %s",
-			       SETTINGS_SEEN_BSSIDS_FILE, error->message);
-		}
-		g_clear_error (&error);
-	}
+	if (!priv->kf_db_seen_bssids)
+		return;
 
 	connection_uuid = nm_settings_connection_get_uuid (self);
-	g_key_file_set_string_list (seen_bssids_file, "seen-bssids", connection_uuid, list, n);
-	g_free (list);
+	if (!connection_uuid)
+		return;
 
-	data = g_key_file_to_data (seen_bssids_file, &len, &error);
-	if (data) {
-		g_file_set_contents (SETTINGS_SEEN_BSSIDS_FILE, data, len, &error);
-		g_free (data);
-	}
-	g_key_file_free (seen_bssids_file);
+	strv = nm_utils_strdict_get_keys (priv->seen_bssids, TRUE, NULL);
 
-	if (error) {
-		_LOGW ("error saving seen-bssids to file '%s': %s",
-		       SETTINGS_SEEN_BSSIDS_FILE, error->message);
-		g_error_free (error);
-	}
-}
-
-/**
- * nm_settings_connection_read_and_fill_seen_bssids:
- * @self: the #NMSettingsConnection
- *
- * Retrieves seen BSSIDs of the connection from database file and stores then into the
- * connection private data.
- **/
-void
-nm_settings_connection_read_and_fill_seen_bssids (NMSettingsConnection *self)
-{
-	NMSettingsConnectionPrivate *priv = NM_SETTINGS_CONNECTION_GET_PRIVATE (self);
-	const char *connection_uuid;
-	GKeyFile *seen_bssids_file;
-	char **tmp_strv = NULL;
-	gsize i, len = 0;
-	NMSettingWireless *s_wifi;
-
-	/* Get seen BSSIDs from database file */
-	seen_bssids_file = g_key_file_new ();
-	g_key_file_set_list_separator (seen_bssids_file, ',');
-	if (g_key_file_load_from_file (seen_bssids_file, SETTINGS_SEEN_BSSIDS_FILE, G_KEY_FILE_KEEP_COMMENTS, NULL)) {
-		connection_uuid = nm_settings_connection_get_uuid (self);
-		tmp_strv = g_key_file_get_string_list (seen_bssids_file, "seen-bssids", connection_uuid, &len, NULL);
-	}
-	g_key_file_free (seen_bssids_file);
-
-	/* Update connection's seen-bssids */
-	if (tmp_strv) {
-		g_hash_table_remove_all (priv->seen_bssids);
-		for (i = 0; i < len; i++)
-			g_hash_table_insert (priv->seen_bssids, tmp_strv[i], tmp_strv[i]);
-		g_free (tmp_strv);
-	} else {
-		/* If this connection didn't have an entry in the seen-bssids database,
-		 * maybe this is the first time we've read it in, so populate the
-		 * seen-bssids list from the deprecated seen-bssids property of the
-		 * wifi setting.
-		 */
-		s_wifi = nm_connection_get_setting_wireless (nm_settings_connection_get_connection (self));
-		if (s_wifi) {
-			len = nm_setting_wireless_get_num_seen_bssids (s_wifi);
-			for (i = 0; i < len; i++) {
-				char *bssid_dup = g_strdup (nm_setting_wireless_get_seen_bssid (s_wifi, i));
-
-				g_hash_table_insert (priv->seen_bssids, bssid_dup, bssid_dup);
-			}
-		}
-	}
+	nm_key_file_db_set_string_list (priv->kf_db_seen_bssids,
+	                                connection_uuid,
+	                                strv ?: NM_PTRARRAY_EMPTY (const char *),
+	                                -1);
 }
 
 /*****************************************************************************/
@@ -2932,6 +2836,9 @@ dispose (GObject *object)
 
 	g_clear_pointer (&priv->filename, g_free);
 
+	g_clear_pointer (&priv->kf_db_timestamps, nm_key_file_db_unref);
+	g_clear_pointer (&priv->kf_db_seen_bssids, nm_key_file_db_unref);
+
 	G_OBJECT_CLASS (nm_settings_connection_parent_class)->dispose (object);
 }
 
diff --git a/src/settings/nm-settings-connection.h b/src/settings/nm-settings-connection.h
index e796b71645..c23f68fcdc 100644
--- a/src/settings/nm-settings-connection.h
+++ b/src/settings/nm-settings-connection.h
@@ -220,14 +220,17 @@ int nm_settings_connection_cmp_timestamp_p_with_data (gconstpointer pa, gconstpo
 int nm_settings_connection_cmp_autoconnect_priority (NMSettingsConnection *a, NMSettingsConnection *b);
 int nm_settings_connection_cmp_autoconnect_priority_p_with_data (gconstpointer pa, gconstpointer pb, gpointer user_data);
 
+struct _NMKeyFileDB;
+
+void nm_settings_connection_register_kf_dbs (NMSettingsConnection *self,
+                                             struct _NMKeyFileDB *kf_db_timestamps,
+                                             struct _NMKeyFileDB *kf_db_seen_bssids);
+
 gboolean nm_settings_connection_get_timestamp (NMSettingsConnection *self,
                                                guint64 *out_timestamp);
 
 void nm_settings_connection_update_timestamp (NMSettingsConnection *self,
-                                              guint64 timestamp,
-                                              gboolean flush_to_disk);
-
-void nm_settings_connection_read_and_fill_timestamp (NMSettingsConnection *self);
+                                              guint64 timestamp);
 
 char **nm_settings_connection_get_seen_bssids (NMSettingsConnection *self);
 
@@ -237,8 +240,6 @@ gboolean nm_settings_connection_has_seen_bssid (NMSettingsConnection *self,
 void nm_settings_connection_add_seen_bssid (NMSettingsConnection *self,
                                             const char *seen_bssid);
 
-void nm_settings_connection_read_and_fill_seen_bssids (NMSettingsConnection *self);
-
 int nm_settings_connection_autoconnect_retries_get (NMSettingsConnection *self);
 void nm_settings_connection_autoconnect_retries_set (NMSettingsConnection *self,
                                                      int retries);
diff --git a/src/settings/nm-settings.c b/src/settings/nm-settings.c
index e594860bcb..9bc3bce95f 100644
--- a/src/settings/nm-settings.c
+++ b/src/settings/nm-settings.c
@@ -37,6 +37,7 @@
 #endif
 
 #include "nm-libnm-core-intern/nm-common-macros.h"
+#include "nm-glib-aux/nm-keyfile-aux.h"
 #include "nm-dbus-interface.h"
 #include "nm-connection.h"
 #include "nm-setting-8021x.h"
@@ -119,6 +120,9 @@ typedef struct {
 
 	GSList *plugins;
 
+	NMKeyFileDB *kf_db_timestamps;
+	NMKeyFileDB *kf_db_seen_bssids;
+
 	CList connections_lst_head;
 
 	NMSettingsConnection **connections_cached_list;
@@ -131,6 +135,9 @@ typedef struct {
 
 	guint connections_len;
 
+	guint kf_db_flush_idle_id_timestamps;
+	guint kf_db_flush_idle_id_seen_bssids;
+
 	bool started:1;
 	bool startup_complete:1;
 	bool connections_loaded:1;
@@ -935,11 +942,9 @@ claim_connection (NMSettings *self, NMSettingsConnection *sett_conn)
 		return;
 	}
 
-	/* Read timestamp from look-aside file and put it into the connection's data */
-	nm_settings_connection_read_and_fill_timestamp (sett_conn);
-
-	/* Read seen-bssids from look-aside file and put it into the connection's data */
-	nm_settings_connection_read_and_fill_seen_bssids (sett_conn);
+	nm_settings_connection_register_kf_dbs (sett_conn,
+	                                        priv->kf_db_timestamps,
+	                                        priv->kf_db_seen_bssids);
 
 	/* Ensure its initial visibility is up-to-date */
 	nm_settings_connection_recheck_visibility (sett_conn);
@@ -1764,6 +1769,128 @@ nm_settings_device_removed (NMSettings *self, NMDevice *device, gboolean quittin
 
 /*****************************************************************************/
 
+G_GNUC_PRINTF (4, 5)
+static void
+_kf_db_log_fcn (NMKeyFileDB *kf_db,
+                int syslog_level,
+                gpointer user_data,
+                const char *fmt,
+                ...)
+{
+	NMSettings *self = user_data;
+	NMLogLevel level = nm_log_level_from_syslog (syslog_level);
+
+	if (_NMLOG_ENABLED (level)) {
+		NMSettingsPrivate *priv = NM_SETTINGS_GET_PRIVATE (self);
+		gs_free char *msg = NULL;
+		va_list ap;
+		const char *prefix;
+
+		va_start (ap, fmt);
+		msg = g_strdup_vprintf (fmt, ap);
+		va_end (ap);
+
+		if (priv->kf_db_timestamps == kf_db)
+			prefix = "timestamps";
+		else if (priv->kf_db_seen_bssids == kf_db)
+			prefix = "seen-bssids";
+		else {
+			nm_assert_not_reached ();
+			prefix = "???";
+		}
+
+		_NMLOG (level, "[%s-keyfile]: %s", prefix, msg);
+	}
+}
+
+static gboolean
+_kf_db_got_dirty_flush (NMSettings *self,
+                        gboolean is_timestamps)
+{
+	NMSettingsPrivate *priv = NM_SETTINGS_GET_PRIVATE (self);
+	const char *prefix;
+	NMKeyFileDB *kf_db;
+
+	if (is_timestamps) {
+		prefix = "timestamps";
+		kf_db = priv->kf_db_timestamps;
+		priv->kf_db_flush_idle_id_timestamps = 0;
+	} else {
+		prefix = "seen-bssids";
+		kf_db = priv->kf_db_seen_bssids;
+		priv->kf_db_flush_idle_id_seen_bssids = 0;
+	}
+
+	if (nm_key_file_db_is_dirty (kf_db))
+		nm_key_file_db_to_file (kf_db, FALSE);
+	else {
+		_LOGT ("[%s-keyfile]: skip saving changes to \"%s\"",
+		       prefix,
+		       nm_key_file_db_get_filename (kf_db));
+	}
+
+	return G_SOURCE_REMOVE;
+}
+
+static gboolean
+_kf_db_got_dirty_flush_timestamps_cb (gpointer user_data)
+{
+	return _kf_db_got_dirty_flush (user_data,
+	                               TRUE);
+}
+
+static gboolean
+_kf_db_got_dirty_flush_seen_bssids_cb (gpointer user_data)
+{
+	return _kf_db_got_dirty_flush (user_data,
+	                               FALSE);
+}
+
+static void
+_kf_db_got_dirty_fcn (NMKeyFileDB *kf_db,
+                      gpointer user_data)
+{
+	NMSettings *self = user_data;
+	NMSettingsPrivate *priv = NM_SETTINGS_GET_PRIVATE (self);
+	GSourceFunc idle_func;
+	guint *p_id;
+	const char *prefix;
+
+	if (priv->kf_db_timestamps == kf_db) {
+		prefix = "timestamps";
+		p_id = &priv->kf_db_flush_idle_id_timestamps;
+		idle_func = _kf_db_got_dirty_flush_timestamps_cb;
+	} else if (priv->kf_db_seen_bssids == kf_db) {
+		prefix = "seen-bssids";
+		p_id = &priv->kf_db_flush_idle_id_seen_bssids;
+		idle_func = _kf_db_got_dirty_flush_seen_bssids_cb;
+	} else {
+		nm_assert_not_reached ();
+		return;
+	}
+
+	if (*p_id != 0)
+		return;
+	_LOGT ("[%s-keyfile]: schedule flushing changes to disk", prefix);
+	*p_id = g_idle_add_full (G_PRIORITY_LOW, idle_func, self, NULL);
+}
+
+void
+nm_settings_kf_db_write (NMSettings *self)
+{
+	NMSettingsPrivate *priv;
+
+	g_return_if_fail (NM_IS_SETTINGS (self));
+
+	priv = NM_SETTINGS_GET_PRIVATE (self);
+	if (priv->kf_db_timestamps)
+		nm_key_file_db_to_file (priv->kf_db_timestamps, TRUE);
+	if (priv->kf_db_seen_bssids)
+		nm_key_file_db_to_file (priv->kf_db_seen_bssids, TRUE);
+}
+
+/*****************************************************************************/
+
 const char *
 nm_settings_get_startup_complete_blocked_reason (NMSettings *self)
 {
@@ -1797,6 +1924,19 @@ nm_settings_start (NMSettings *self, GError **error)
 
 	priv = NM_SETTINGS_GET_PRIVATE (self);
 
+	priv->kf_db_timestamps = nm_key_file_db_new (NMSTATEDIR "/timestamps",
+	                                             "timestamps",
+	                                             _kf_db_log_fcn,
+	                                             _kf_db_got_dirty_fcn,
+	                                             self);
+	priv->kf_db_seen_bssids = nm_key_file_db_new (NMSTATEDIR "/seen-bssids",
+	                                              "seen-bssids",
+	                                              _kf_db_log_fcn,
+	                                              _kf_db_got_dirty_fcn,
+	                                              self);
+	nm_key_file_db_start (priv->kf_db_timestamps);
+	nm_key_file_db_start (priv->kf_db_seen_bssids);
+
 	/* Load the plugins; fail if a plugin is not found. */
 	plugins = nm_config_data_get_plugins (nm_config_get_data_orig (priv->config), TRUE);
 
@@ -1933,6 +2073,13 @@ finalize (GObject *object)
 
 	g_clear_object (&priv->config);
 
+	nm_clear_g_source (&priv->kf_db_flush_idle_id_timestamps);
+	nm_clear_g_source (&priv->kf_db_flush_idle_id_seen_bssids);
+	nm_key_file_db_to_file (priv->kf_db_timestamps, FALSE);
+	nm_key_file_db_to_file (priv->kf_db_seen_bssids, FALSE);
+	nm_key_file_db_destroy (priv->kf_db_timestamps);
+	nm_key_file_db_destroy (priv->kf_db_seen_bssids);
+
 	G_OBJECT_CLASS (nm_settings_parent_class)->finalize (object);
 }
 
diff --git a/src/settings/nm-settings.h b/src/settings/nm-settings.h
index eb74c09c4a..a3bd26a938 100644
--- a/src/settings/nm-settings.h
+++ b/src/settings/nm-settings.h
@@ -114,4 +114,6 @@ void nm_settings_device_removed (NMSettings *self, NMDevice *device, gboolean qu
 
 const char *nm_settings_get_startup_complete_blocked_reason (NMSettings *self);
 
+void nm_settings_kf_db_write (NMSettings *settings);
+
 #endif  /* __NM_SETTINGS_H__ */