hints: fix copy of filter

Only the first entry of the filter array was being
included in the copy of the filter, rather than the
entire thing.  The result is that hints would not be
refreshed if the filter was changed but the first
entry was unchanged.

lib/label/hints.c

@@ -579,6 +579,52 @@ static void _apply_hints(struct cmd_context *cmd, struct dm_list *hints,
 	}
 }
 
+static void _filter_to_str(struct cmd_context *cmd, int filter_cfg, char **strp)
+{
+	const struct dm_config_node *cn;
+	const struct dm_config_value *cv;
+	char *str;
+	int pos = 0;
+	int len = 0;
+	int ret;
+
+	*strp = NULL;
+
+	if (!(cn = find_config_tree_array(cmd, filter_cfg, NULL))) {
+		/* shouldn't happen because default is a|*| */
+		return;
+	}
+
+	for (cv = cn->v; cv; cv = cv->next) {
+		if (cv->type != DM_CFG_STRING)
+			continue;
+
+		len += (strlen(cv->v.str) + 1);
+	}
+	len++;
+
+	if (len == 1) {
+		/* shouldn't happen because default is a|*| */
+		return;
+	}
+
+	str = malloc(len);
+	memset(str, 0, len);
+
+	for (cv = cn->v; cv; cv = cv->next) {
+		if (cv->type != DM_CFG_STRING)
+			continue;
+
+		ret = snprintf(str + pos, len - pos, "%s", cv->v.str);
+
+		if (ret >= len - pos)
+			break;
+		pos += ret;
+	}
+
+	*strp = str;
+}
+
 /*
  * Return 1 and needs_refresh 0: the hints can be used
  * Return 1 and needs_refresh 1: the hints can't be used and should be updated
@@ -590,12 +636,11 @@ static int _read_hint_file(struct cmd_context *cmd, struct dm_list *hints, int *
 {
 	char devpath[PATH_MAX];
 	FILE *fp;
-	const struct dm_config_node *cn;
 	struct dev_iter *iter;
 	struct hint *hint;
 	struct device *dev;
 	char *split[HINT_LINE_WORDS];
-	char *name, *pvid, *devn, *vgname, *p;
+	char *name, *pvid, *devn, *vgname, *p, *filter_str = NULL;
 	uint32_t read_hash = 0;
 	uint32_t calc_hash = INITIAL_CRC;
 	uint32_t read_count = 0;
@@ -655,23 +700,31 @@ static int _read_hint_file(struct cmd_context *cmd, struct dm_list *hints, int *
 
 		keylen = strlen("global_filter:");
 		if (!strncmp(_hint_line, "global_filter:", keylen)) {
-			cn = find_config_tree_array(cmd, devices_global_filter_CFG, NULL);
+			_filter_to_str(cmd, devices_global_filter_CFG, &filter_str);
-			if (strcmp(cn->v->v.str, _hint_line + keylen)) {
+			if (!filter_str || strcmp(filter_str, _hint_line + keylen)) {
 				log_debug("ignore hints with different global_filter");
+				if (filter_str)
+					free(filter_str);
 				*needs_refresh = 1;
 				break;
 			}
+			if (filter_str)
+				free(filter_str);
 			continue;
 		}
 
 		keylen = strlen("filter:");
 		if (!strncmp(_hint_line, "filter:", keylen)) {
-			cn = find_config_tree_array(cmd, devices_filter_CFG, NULL);
+			_filter_to_str(cmd, devices_filter_CFG, &filter_str);
-			if (strcmp(cn->v->v.str, _hint_line + keylen)) {
+			if (!filter_str || strcmp(filter_str, _hint_line + keylen)) {
 				log_debug("ignore hints with different filter");
+				if (filter_str)
+					free(filter_str);
 				*needs_refresh = 1;
 				break;
 			}
+			if (filter_str)
+				free(filter_str);
 			continue;
 		}
 
@@ -800,11 +853,11 @@ int write_hint_file(struct cmd_context *cmd, int newhints)
 {
 	char devpath[PATH_MAX];
 	FILE *fp;
-	const struct dm_config_node *cn;
 	struct lvmcache_info *info;
 	struct dev_iter *iter;
 	struct device *dev;
 	const char *vgname;
+	char *filter_str = NULL;
 	uint32_t hash = INITIAL_CRC;
 	uint32_t count = 0;
 	time_t t;
@@ -855,11 +908,15 @@ int write_hint_file(struct cmd_context *cmd, int newhints)
 	fprintf(fp, "# Created by %s pid %d %s", cmd->name, getpid(), ctime(&t));
 	fprintf(fp, "hints_version: %d.%d\n", HINTS_VERSION_MAJOR, HINTS_VERSION_MINOR);
 
-	cn = find_config_tree_array(cmd, devices_global_filter_CFG, NULL);
+	_filter_to_str(cmd, devices_global_filter_CFG, &filter_str);
-	fprintf(fp, "global_filter:%s\n", cn->v->v.str);
+	fprintf(fp, "global_filter:%s\n", filter_str ?: "-");
+	if (filter_str)
+		free(filter_str);
 
-	cn = find_config_tree_array(cmd, devices_filter_CFG, NULL);
+	_filter_to_str(cmd, devices_filter_CFG, &filter_str);
-	fprintf(fp, "filter:%s\n", cn->v->v.str);
+	fprintf(fp, "filter:%s\n", filter_str ?: "-");
+	if (filter_str)
+		free(filter_str);
 
 	fprintf(fp, "scan_lvs:%d\n", cmd->scan_lvs);