cachevol: improve manipulation with dm tree

Enhance activation of cached devices using cachevol.
Correctly instatiace  cachevol -cdata & -cmeta devices with
'-' in name (as they are only layered devices).
Code is also a bit more compacted (although still not ideal,
as the usage of extra UUIDs stored in metadata is troublesome
and will be repaired later).

NOTE: this patch my brink potentially minor incompatiblity for 'runtime' upgrade

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.03.06 - 
 ================================
+  Enhance activation of cache devices with cachevols.
   Add _cvol in list of protected suffixes and start use it with DM UUID.
   Rename LV converted to cachevol to use _cvol suffix.
   Use normal LVs for wiping of cachevols.

lib/activate/dev_manager.c

@@ -2447,6 +2447,49 @@ static int _pool_register_callback(struct dev_manager *dm,
 	return 1;
 }
 
+/* Add special devices _cmeta & _cdata on top of CacheVol to dm tree */
+static int _add_cvol_subdev_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
+				     const struct logical_volume *lv, int meta_or_data)
+{
+	const char *layer = meta_or_data ? "cmeta" : "cdata";
+	struct dm_pool *mem = dm->track_pending_delete ? dm->cmd->pending_delete_mem : dm->mem;
+	const struct logical_volume *pool_lv = first_seg(lv)->pool_lv;
+	struct lv_segment *lvseg = first_seg(lv);
+	struct dm_info info;
+	char *name ,*dlid;
+	union lvid lvid = { 0 };
+
+	/* TODO: Convert to use just  CVOL UUID with suffix */
+	memcpy(&lvid.id[0], &lv->vg->id, sizeof(struct id));
+	memcpy(&lvid.id[1], (meta_or_data) ? &lvseg->metadata_id : &lvseg->data_id, sizeof(struct id));
+
+	if (!(dlid = dm_build_dm_uuid(mem, UUID_PREFIX, (const char *)&lvid.s, layer)))
+		return_0;
+
+	/* Name is actually not really needed here, but aids debugging... */
+	if (!(name = dm_build_dm_name(dm->mem, lv->vg->name, pool_lv->name, layer)))
+		return_0;
+
+	if (!_info(dm->cmd, name, dlid, 1, 0, &info, NULL, NULL))
+		return_0;
+
+	if (info.exists) {
+		if (!dm_tree_add_dev_with_udev_flags(dtree, info.major, info.minor,
+						     _get_udev_flags(dm, lv, layer, 0, 0, 0))) {
+			log_error("Failed to add device (%" PRIu32 ":%" PRIu32") to dtree.", info.major, info.minor);
+			return 0;
+		}
+		if (dm->track_pending_delete) {
+			log_debug_activation("Tracking pending delete for %s %s (%s).",
+					     layer, display_lvname(lv), dlid);
+			if (!str_list_add(mem, &dm->cmd->pending_delete, dlid))
+				return_0;
+		}
+	}
+
+	return 1;
+}
+
 /* Declaration to resolve suspend tree and message passing for thin-pool */
 static int _add_target_to_dtree(struct dev_manager *dm,
 				struct dm_tree_node *dnode,
@@ -2481,51 +2524,11 @@ static int _add_lv_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
 		/* Unused cache pool is activated as metadata */
 	}
 
-	if (lv_is_cache(lv) && lv_is_cache_vol(first_seg(lv)->pool_lv) && dm->activation) {
+	if (lv_is_cache(lv) && (plv = (first_seg(lv)->pool_lv)) && lv_is_cache_vol(plv)) {
-		struct logical_volume *pool_lv = first_seg(lv)->pool_lv;
+		if (!_add_cvol_subdev_to_dtree(dm, dtree, lv, 0) ||
-		struct lv_segment *lvseg = first_seg(lv);
+		    !_add_cvol_subdev_to_dtree(dm, dtree, lv, 1) ||
-		struct dm_info info_meta;
+		    !_add_dev_to_dtree(dm, dtree, plv, lv_layer(plv)))
-		struct dm_info info_data;
-		union lvid lvid_meta;
-		union lvid lvid_data;
-		char *name_meta;
-		char *name_data;
-		char *dlid_meta;
-		char *dlid_data;
-
-		memset(&lvid_meta, 0, sizeof(lvid_meta));
-		memset(&lvid_data, 0, sizeof(lvid_meta));
-		memcpy(&lvid_meta.id[0], &lv->vg->id, sizeof(struct id));
-		memcpy(&lvid_meta.id[1], &lvseg->metadata_id, sizeof(struct id));
-		memcpy(&lvid_data.id[0], &lv->vg->id, sizeof(struct id));
-		memcpy(&lvid_data.id[1], &lvseg->data_id, sizeof(struct id));
-
-		if (!(dlid_meta = dm_build_dm_uuid(dm->mem, UUID_PREFIX, (const char *)&lvid_meta.s, "cmeta")))
 			return_0;
-		if (!(dlid_data = dm_build_dm_uuid(dm->mem, UUID_PREFIX, (const char *)&lvid_data.s, "cdata")))
-			return_0;
-		if (!(name_meta = dm_build_dm_name(dm->mem, lv->vg->name, pool_lv->name, "_cmeta")))
-			return_0;
-		if (!(name_data = dm_build_dm_name(dm->mem, lv->vg->name, pool_lv->name, "_cdata")))
-			return_0;
-
-		if (!_info(dm->cmd, name_meta, dlid_meta, 1, 0, &info_meta, NULL, NULL))
-			return_0;
-
-		if (!_info(dm->cmd, name_data, dlid_data, 1, 0, &info_data, NULL, NULL))
-			return_0;
-
-		if (info_meta.exists &&
-		    !dm_tree_add_dev_with_udev_flags(dtree, info_meta.major, info_meta.minor,
-						     _get_udev_flags(dm, lv, NULL, 0, 0, 0))) {
-			log_error("Failed to add device (%" PRIu32 ":%" PRIu32") to dtree.", info_meta.major, info_meta.minor);
-		}
-
-		if (info_data.exists &&
-		    !dm_tree_add_dev_with_udev_flags(dtree, info_data.major, info_data.minor,
-						     _get_udev_flags(dm, lv, NULL, 0, 0, 0))) {
-			log_error("Failed to add device (%" PRIu32 ":%" PRIu32") to dtree.", info_data.major, info_data.minor);
-		}
 	}
 
 	if (!origin_only && !_add_dev_to_dtree(dm, dtree, lv, NULL))
@@ -3228,11 +3231,14 @@ static int _add_new_lv_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
 					     laopts->noscan, laopts->temporary,
 					     0);
 
-		log_debug("Add cache pool %s to dtree before cache %s", pool_lv->name, lv->name);
+		if (lv_is_pending_delete(lvseg->lv))
+			dm->track_pending_delete = 1;
 
-		if (!_add_new_lv_to_dtree(dm, dtree, pool_lv, laopts, NULL)) {
+		log_debug("Add cachevol %s to dtree before cache %s.", pool_lv->name, lv->name);
-			log_error("Failed to add cachepool to dtree before cache");
+
-			return_0;
+		if (!_add_new_lv_to_dtree(dm, dtree, pool_lv, laopts, lv_layer(pool_lv))) {
+			log_error("Failed to add cachevol to dtree before cache.");
+			return 0;
 		}
 
 		memset(&lvid_meta, 0, sizeof(lvid_meta));
@@ -3247,9 +3253,9 @@ static int _add_new_lv_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
 		if (!(dlid_data = dm_build_dm_uuid(dm->mem, UUID_PREFIX, (const char *)&lvid_data.s, "cdata")))
 			return_0;
 
-		if (!(name_meta = dm_build_dm_name(dm->mem, vg->name, pool_lv->name, "_cmeta")))
+		if (!(name_meta = dm_build_dm_name(dm->mem, vg->name, pool_lv->name, "cmeta")))
 			return_0;
-		if (!(name_data = dm_build_dm_name(dm->mem, vg->name, pool_lv->name, "_cdata")))
+		if (!(name_data = dm_build_dm_name(dm->mem, vg->name, pool_lv->name, "cdata")))
 			return_0;
 
 		if (!(dlid_pool = build_dm_uuid(dm->mem, pool_lv, NULL)))
@@ -3266,6 +3272,11 @@ static int _add_new_lv_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
 								  udev_flags)))
 			return_0;
 
+		if (dm->track_pending_delete) {
+			log_debug_activation("Using error for pending meta delete %s.", display_lvname(lv));
+			if (!dm_tree_node_add_error_target(dnode_meta, (uint64_t)lv->vg->extent_size * meta_len))
+				return_0;
+		} else {
 			/* add load_segment to meta dnode: linear, size of meta area */
 			if (!add_linear_area_to_dtree(dnode_meta,
 						      meta_len,
@@ -3277,6 +3288,7 @@ static int _add_new_lv_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
 			/* add seg_area to prev load_seg: offset 0 maps to cachepool lv offset 0 */
 			if (!dm_tree_node_add_target_area(dnode_meta, NULL, dlid_pool, 0))
 				return_0;
+		}
 
 		/* add data dnode */
 		if (!(dnode_data = dm_tree_add_new_dev_with_udev_flags(dtree,
@@ -3289,6 +3301,11 @@ static int _add_new_lv_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
 								  udev_flags)))
 			return_0;
 
+		if (dm->track_pending_delete) {
+			log_debug_activation("Using error for pending data delete %s.", display_lvname(lv));
+			if (!dm_tree_node_add_error_target(dnode_data, (uint64_t)lv->vg->extent_size * data_len))
+				return_0;
+		} else {
 			/* add load_segment to data dnode: linear, size of data area */
 			if (!add_linear_area_to_dtree(dnode_data,
 						      data_len,
@@ -3301,6 +3318,7 @@ static int _add_new_lv_to_dtree(struct dev_manager *dm, struct dm_tree *dtree,
 			if (!dm_tree_node_add_target_area(dnode_data, NULL, dlid_pool, meta_len))
 				return_0;
 		}
+	}
 
 	/* FIXME Seek a simpler way to lay out the snapshot-merge tree. */