activate: add get_device_list

Add funtion get_device_list() to get list of active DM devices.
Handled through new dm_task_get_device_list().

lib/activate/activate.c

@@ -624,6 +624,15 @@ int target_present(struct cmd_context *cmd, const char *target_name,
 				      &maj, &min, &patchlevel);
 }
 
+int get_device_list(const struct volume_group *vg, struct dm_list **devs,
+		    unsigned *devs_features)
+{
+	if (!activation())
+		return 0;
+
+	return dev_manager_get_device_list(NULL, devs, devs_features);
+}
+
 /*
  * When '*info' is NULL, returns 1 only when LV is active.
  * When '*info' != NULL, returns 1 when info structure is populated.

lib/activate/activate.h

@@ -106,6 +106,10 @@ int target_present(struct cmd_context *cmd, const char *target_name,
 		   int use_modprobe);
 int target_version(const char *target_name, uint32_t *maj,
 		   uint32_t *min, uint32_t *patchlevel);
+
+int get_device_list(const struct volume_group *vg, struct dm_list **devs,
+		    unsigned *devs_features);
+
 int raid4_is_supported(struct cmd_context *cmd, const struct segment_type *segtype);
 int lvm_dm_prefix_check(int major, int minor, const char *prefix);
 int list_segment_modules(struct dm_pool *mem, const struct lv_segment *seg,

lib/activate/dev_manager.c

@@ -138,8 +138,16 @@ static struct dm_task *_setup_task_run(int task, struct dm_info *info,
 	if (!with_flush && !dm_task_no_flush(dmt))
 		log_warn("WARNING: Failed to set no_flush.");
 
-	if (task == DM_DEVICE_TARGET_MSG)
+	switch (task) {
+	case DM_DEVICE_TARGET_MSG:
 		return dmt; /* TARGET_MSG needs more local tweaking before task_run() */
+	case DM_DEVICE_LIST:
+		if (!dm_task_set_newuuid(dmt, " ")) // new uuid has no meaning here
+			log_warn("WARNING: Failed to query uuid with LIST.");
+		break;
+	default:
+		break;
+	}
 
 	if (!dm_task_run(dmt))
 		goto_out;
@@ -922,6 +930,25 @@ int dev_manager_check_prefix_dm_major_minor(uint32_t major, uint32_t minor, cons
 	return r;
 }
 
+int dev_manager_get_device_list(const char *prefix, struct dm_list **devs, unsigned *devs_features)
+{
+	struct dm_task *dmt;
+	int r = 1;
+
+	if (!(dmt = _setup_task_run(DM_DEVICE_LIST, NULL, NULL, NULL, 0, 0, 0, 0, 0, 0)))
+		return_0;
+
+	if (!dm_task_get_device_list(dmt, devs, devs_features)) {
+		r = 0;
+		goto_out;
+	}
+
+    out:
+	dm_task_destroy(dmt);
+
+	return r;
+}
+
 int dev_manager_info(struct cmd_context *cmd,
 		     const struct logical_volume *lv, const char *layer,
 		     int with_open_count, int with_read_ahead, int with_name_check,

lib/activate/dev_manager.h

@@ -103,5 +103,7 @@ int dev_manager_device_uses_vg(struct device *dev,
 int dev_manager_remove_dm_major_minor(uint32_t major, uint32_t minor);
 
 int dev_manager_check_prefix_dm_major_minor(uint32_t major, uint32_t minor, const char *prefix);
+int dev_manager_get_device_list(const char *prefix, struct dm_list **devs,
+				unsigned *devs_features);
 
 #endif