Merge pull request #68 from micrakow/create_exp_objs_fix

Fix error handling in case of fatal cache stop error

modules/cas_cache/cas_cache.h

@@ -72,6 +72,7 @@ struct casdsk_functions_mapper {
 	int (*casdsk_exp_obj_destroy)(struct casdsk_disk *dsk);
 	int (*casdsk_exp_obj_create)(struct casdsk_disk *dsk, const char *dev_name,
 		struct module *owner, struct casdsk_exp_obj_ops *ops);
+	void(*casdsk_exp_obj_free)(struct casdsk_disk *dsk);
 	struct request_queue *(*casdsk_disk_get_queue)(struct casdsk_disk *dsk);
 	void (*casdsk_store_config)(size_t n_blobs, struct casdsk_props_conf *blobs);
 	struct block_device *(*casdsk_disk_get_blkdev)(struct casdsk_disk *dsk);

modules/cas_cache/layer_cache_management.c

@@ -1565,13 +1565,11 @@ out:
 }
 
 /**
- * @brief routine implements --remove-cache command.
- * @param[in] device caching device to be removed
+ * @brief routine implements --stop-cache command.
+ * @param[in] cache_id caching device id to be removed
  * @param[in] flush Boolean: shall we flush dirty data before removing cache.
  *		if yes, flushing may still be interrupted by user (in which case
  *		device won't be actually removed and error will be returned)
- * @param[in] allow_interruption shall we allow interruption of dirty
- *		data flushing
  */
 int cache_mngt_exit_instance(ocf_cache_id_t id, int flush)
 {
@@ -1648,7 +1646,7 @@ int cache_mngt_exit_instance(ocf_cache_id_t id, int flush)
 	/* Stop cache device */
 	status = _cache_mngt_cache_stop_sync(cache);
 	if (status && status != -OCF_ERR_WRITE_CACHE)
-		goto unlock;
+		goto restore_exp_obj;
 
 	if (!status && flush_status)
 		status = -KCAS_ERR_STOPPED_DIRTY;
@@ -1660,6 +1658,24 @@ int cache_mngt_exit_instance(ocf_cache_id_t id, int flush)
 	ocf_queue_put(cache_priv->mngt_queue);
 	vfree(cache_priv);
 
+	ocf_mngt_cache_unlock(cache);
+	ocf_mngt_cache_put(cache);
+
+	return status;
+
+restore_exp_obj:
+	if (block_dev_create_all_exported_objects(cache)) {
+		/* Print error msg but do not change return err code to inform user why
+		* stop failed originally. */
+		printk(KERN_WARNING
+			"Failed to restore (create) all exported objects!\n");
+		goto unlock;
+	}
+	if (block_dev_activate_all_exported_objects(cache)) {
+		block_dev_destroy_all_exported_objects(cache);
+		printk(KERN_WARNING
+			"Failed to restore (activate) all exported objects!\n");
+	}
 unlock:
 	ocf_mngt_cache_unlock(cache);
 put:

modules/cas_cache/main.c

@@ -79,6 +79,7 @@ int static cas_casdisk_lookup_funtions(void)
 	cas_lookup_symbol(casdsk_disk_dettach);
 	cas_lookup_symbol(casdsk_exp_obj_destroy);
 	cas_lookup_symbol(casdsk_exp_obj_create);
+	cas_lookup_symbol(casdsk_exp_obj_free);
 	cas_lookup_symbol(casdsk_disk_get_queue);
 	cas_lookup_symbol(casdsk_store_config);
 	cas_lookup_symbol(casdsk_disk_get_blkdev);

modules/cas_cache/volume/vol_block_dev_bottom.c

@@ -29,7 +29,7 @@ int block_dev_open_object(ocf_volume_t vol, void *volume_params)
 	struct casdsk_disk *dsk;
 
 	if (bdobj->opened_by_bdev) {
-		/* Bdev has beed set manually, so there is nothing to do. */
+		/* Bdev has been set manually, so there is nothing to do. */
 		return 0;
 	}
 

modules/cas_cache/volume/vol_block_dev_top.c

@@ -884,6 +884,17 @@ int block_dev_activate_exported_object(ocf_core_t core)
 	return ret;
 }
 
+static int _block_dev_activate_exported_object(ocf_core_t core, void *cntx)
+{
+	return block_dev_activate_exported_object(core);
+}
+
+int block_dev_activate_all_exported_objects(ocf_cache_t cache)
+{
+	return ocf_core_visit(cache, _block_dev_activate_exported_object, NULL,
+			true);
+}
+
 int block_dev_create_exported_object(ocf_core_t core)
 {
 	ocf_volume_t obj = ocf_core_get_volume(core);
@@ -915,6 +926,17 @@ int block_dev_create_exported_object(ocf_core_t core)
 	return result;
 }
 
+static int _block_dev_create_exported_object_visitor(ocf_core_t core, void *cntx)
+{
+	return block_dev_create_exported_object(core);
+}
+
+int block_dev_create_all_exported_objects(ocf_cache_t cache)
+{
+	return ocf_core_visit(cache, _block_dev_create_exported_object_visitor, NULL,
+			true);
+}
+
 int block_dev_destroy_exported_object(ocf_core_t core)
 {
 	int ret = 0;
@@ -1014,5 +1036,21 @@ int block_dev_destroy_all_exported_objects(ocf_cache_t cache)
 
 	ocf_core_visit(cache, _block_dev_stop_exported_object, NULL, true);
 
+	block_dev_free_all_exported_objects(cache);
 	return 0;
 }
+
+static int _block_dev_free_exported_object(ocf_core_t core, void *cntx)
+{
+	struct bd_object *bvol = bd_object(
+			ocf_core_get_volume(core));
+
+	casdisk_functions.casdsk_exp_obj_free(bvol->dsk);
+	return 0;
+}
+
+int block_dev_free_all_exported_objects(ocf_cache_t cache)
+{
+	return ocf_core_visit(cache, _block_dev_free_exported_object, NULL,
+			true);
+}

modules/cas_cache/volume/vol_block_dev_top.h

@@ -6,12 +6,15 @@
 #ifndef __VOL_BLOCK_DEV_TOP_H__
 #define __VOL_BLOCK_DEV_TOP_H__
 
+int block_dev_activate_all_exported_objects(ocf_cache_t cache);
 int block_dev_activate_exported_object(ocf_core_t core);
 
+int block_dev_create_all_exported_objects(ocf_cache_t cache);
 int block_dev_create_exported_object(ocf_core_t core);
 
+int block_dev_destroy_all_exported_objects(ocf_cache_t cache);
 int block_dev_destroy_exported_object(ocf_core_t core);
 
-int block_dev_destroy_all_exported_objects(ocf_cache_t cache);
+int block_dev_free_all_exported_objects(ocf_cache_t cache);
 
 #endif /* __VOL_BLOCK_DEV_TOP_H__ */

modules/cas_disk/exp_obj.c

@@ -421,6 +421,7 @@ void casdsk_exp_obj_free(struct casdsk_disk *dsk)
 	kobject_put(&exp_obj->kobj);
 	dsk->exp_obj = NULL;
 }
+EXPORT_SYMBOL(casdsk_exp_obj_free);
 
 static void __casdsk_exp_obj_release(struct casdsk_exp_obj *exp_obj)
 {
@@ -723,7 +724,10 @@ int casdsk_exp_obj_destroy(struct casdsk_disk *dsk)
 	struct casdsk_exp_obj *exp_obj;
 
 	BUG_ON(!dsk);
-	BUG_ON(!dsk->exp_obj);
+
+	if (!dsk->exp_obj)
+		return -ENODEV;
+
 	BUG_ON(!dsk->exp_obj->locked_bd);
 
 	CASDSK_DEBUG_DISK_TRACE(dsk);