toollib: avoid repeated lvmetad vg_lookupdev-dct-vgnameids

In process_each_vg and process_each_lv when no vgname
args are given, the first step is to get a list of all
vgid/vgname on the system.  This is exactly what lvmetad
returns from a vg_list request.  The current code is
doing a vg_lookup on each VG after the vg_list and
populating lvmcache with the info for each VG.  These
preliminary vg_lookup's are unnecessary, because they
will be done again when the processing functions call
vg_read.  This patch eliminates the initial round of
vg_lookup's, which can roughly cut in half the number
of lvmetad requests and save a lot of extra work.

6 files changed, 123 insertions, 36 deletions

diff --git a/lib/cache/lvmcache.c b/lib/cache/lvmcache.c
index 5c5a9ab2d..5ee7a9c6c 100644
--- a/lib/cache/lvmcache.c
+++ b/lib/cache/lvmcache.c
@@ -885,6 +885,37 @@ int lvmcache_vginfo_holders_dec_and_test_for_zero(struct lvmcache_vginfo *vginfo
 }
 // #endif
 
+int lvmcache_get_vgnameids(struct cmd_context *cmd, int include_internal,
+			   struct dm_list *vgnameids)
+{
+	struct vgnameid_list *vgnl;
+	struct lvmcache_vginfo *vginfo;
+
+	lvmcache_label_scan(cmd, 0);
+
+	dm_list_iterate_items(vginfo, &_vginfos) {
+		if (!include_internal && is_orphan_vg(vginfo->vgname))
+			continue;
+
+		if (!(vgnl = dm_pool_alloc(cmd->mem, sizeof(*vgnl)))) {
+			log_error("vgnameid_list allocation failed.");
+			return 0;
+		}
+
+		vgnl->vgid = dm_pool_strdup(cmd->mem, vginfo->vgid);
+		vgnl->vg_name = dm_pool_strdup(cmd->mem, vginfo->vgname);
+
+		if (!vgnl->vgid || !vgnl->vg_name) {
+			log_error("vgnameid_list member allocation failed.");
+			return 0;
+		}
+
+		dm_list_add(vgnameids, &vgnl->list);
+	}
+
+	return 1;
+}
+
 struct dm_list *lvmcache_get_vgids(struct cmd_context *cmd,
 				   int include_internal)
 {
diff --git a/lib/cache/lvmcache.h b/lib/cache/lvmcache.h
index 015f650a7..aea56cc32 100644
--- a/lib/cache/lvmcache.h
+++ b/lib/cache/lvmcache.h
@@ -107,6 +107,9 @@ struct dm_list *lvmcache_get_vgnames(struct cmd_context *cmd,
 struct dm_list *lvmcache_get_vgids(struct cmd_context *cmd,
 				   int include_internal);
 
+int lvmcache_get_vgnameids(struct cmd_context *cmd, int include_internal,
+                          struct dm_list *vgnameids);
+
 /* Returns list of struct dm_str_list containing pool-allocated copy of pvids */
 struct dm_list *lvmcache_get_pvids(struct cmd_context *cmd, const char *vgname,
 				const char *vgid);
diff --git a/lib/cache/lvmetad.c b/lib/cache/lvmetad.c
index 0894c791c..cd9fe8890 100644
--- a/lib/cache/lvmetad.c
+++ b/lib/cache/lvmetad.c
@@ -673,6 +673,57 @@ int lvmetad_pv_list_to_lvmcache(struct cmd_context *cmd)
 	return 1;
 }
 
+int lvmetad_get_vgnameids(struct cmd_context *cmd, int include_internal,
+			  struct dm_list *vgnameids)
+{
+	struct vgnameid_list *vgnl;
+	struct id vgid;
+	const char *vgid_txt;
+	const char *vg_name;
+	daemon_reply reply;
+	struct dm_config_node *cn;
+
+	log_debug_lvmetad("Asking lvmetad for complete list of known VG ids/names");
+	reply = _lvmetad_send("vg_list", NULL);
+	if (!_lvmetad_handle_reply(reply, "list VGs", "", NULL)) {
+		daemon_reply_destroy(reply);
+		return_0;
+	}
+
+	if ((cn = dm_config_find_node(reply.cft->root, "volume_groups"))) {
+		for (cn = cn->child; cn; cn = cn->sib) {
+			vgid_txt = cn->key;
+			if (!id_read_format(&vgid, vgid_txt)) {
+				stack;
+				continue;
+			}
+
+			if (!(vgnl = dm_pool_alloc(cmd->mem, sizeof(*vgnl)))) {
+				log_error("vgnameid_list allocation failed.");
+				return 0;
+			}
+
+			if (!(vg_name = dm_config_find_str(cn->child, "name", NULL))) {
+				log_error("vg_list no name found.");
+				return 0;
+			}
+
+			vgnl->vgid = dm_pool_strdup(cmd->mem, (char *)&vgid);
+			vgnl->vg_name = dm_pool_strdup(cmd->mem, vg_name);
+
+			if (!vgnl->vgid || !vgnl->vg_name) {
+				log_error("vgnameid_list member allocation failed.");
+				return 0;
+			}
+
+			dm_list_add(vgnameids, &vgnl->list);
+		}
+	}
+
+	daemon_reply_destroy(reply);
+	return 1;
+}
+
 int lvmetad_vg_list_to_lvmcache(struct cmd_context *cmd)
 {
 	struct volume_group *tmp;
diff --git a/lib/cache/lvmetad.h b/lib/cache/lvmetad.h
index b5bac69e4..dcbd8d94d 100644
--- a/lib/cache/lvmetad.h
+++ b/lib/cache/lvmetad.h
@@ -143,6 +143,13 @@ int lvmetad_pv_lookup_by_dev(struct cmd_context *cmd, struct device *dev, int *f
 int lvmetad_vg_list_to_lvmcache(struct cmd_context *cmd);
 
 /*
+ * Request a list of vgid/vgname pairs for all VGs known to lvmetad.
+ * Does not do vg_lookup's on each VG, and does not populate lvmcache.
+ */
+int lvmetad_get_vgnameids(struct cmd_context *cmd, int include_internal,
+                          struct dm_list *vgnameids);
+
+/*
  * Find a VG by its ID or its name in the lvmetad cache. Gives NULL if the VG is
  * not found.
  */
diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
index 47fb9ae56..d8f92f6a7 100644
--- a/lib/metadata/metadata-exported.h
+++ b/lib/metadata/metadata-exported.h
@@ -494,6 +494,12 @@ struct vg_list {
 	struct volume_group *vg;
 };
 
+struct vgnameid_list {
+	struct dm_list list;
+	const char *vg_name;
+	const char *vgid;
+};
+
 #define PV_PE_START_CALC ((uint64_t) -1) /* Calculate pe_start value */
 
 struct pvcreate_restorable_params {
diff --git a/tools/toollib.c b/tools/toollib.c
index e6c3cdb5e..cda8051be 100644
--- a/tools/toollib.c
+++ b/tools/toollib.c
@@ -1515,12 +1515,6 @@ int validate_restricted_lvname_param(struct cmd_context *cmd, const char **vg_na
 	return -1;
 }
 
-struct vgnameid_list {
-	struct dm_list list;
-	const char *vg_name;
-	const char *vgid;
-};
-
 /*
  * Extract list of VG names and list of tags from command line arguments.
  */
@@ -1594,9 +1588,6 @@ static int _get_vgnameids_on_system(struct cmd_context *cmd,
 				    const char *only_this_vgname, int include_internal)
 {
 	struct vgnameid_list *vgnl;
-	struct dm_list *vgids;
-	struct dm_str_list *sl;
-	const char *vgid;
 
 	if (only_this_vgname) {
 		vgnl = dm_pool_alloc(cmd->mem, sizeof(*vgnl));
@@ -1614,32 +1605,30 @@ static int _get_vgnameids_on_system(struct cmd_context *cmd,
 
 	log_verbose("Finding all volume groups.");
 
-	if (!lvmetad_vg_list_to_lvmcache(cmd))
-		stack;
-
-	/*
-	 * Start with complete vgid list because multiple VGs might have same name.
-	 */
-	vgids = get_vgids(cmd, include_internal);
-	if (!vgids || dm_list_empty(vgids)) {
-		stack;
-		return ECMD_PROCESSED;
-	}
-
-	/* FIXME get_vgids() should provide these pairings directly */
-	dm_list_iterate_items(sl, vgids) {
-		if (!(vgid = sl->str))
-			continue;
-
-		if (!(vgnl = dm_pool_alloc(cmd->mem, sizeof(*vgnl)))) {
-			log_error("vgnameid_list allocation failed.");
-			return ECMD_FAILED;
-		}
+	if (lvmetad_active() && include_internal) {
+		/*
+		 * Used by process_each_pv which needs to initially read all
+		 * vgs to populate device/lvmcache so that pvids are available
+		 * and duplicates identified while processing the pvs, and
+		 * so that process_each_pv can process the orphan vg, which
+		 * is available through lvmcache, but not from lvmetad.
+		 */
+		lvmetad_vg_list_to_lvmcache(cmd);
+		lvmcache_get_vgnameids(cmd, include_internal, vgnameids_on_system);
 
-		vgnl->vgid = dm_pool_strdup(cmd->mem, vgid);
-		vgnl->vg_name = lvmcache_vgname_from_vgid(cmd->mem, vgid);
+	} else if (lvmetad_active() && !include_internal) {
+		/*
+		 * We can avoid reading all vgs from lvmetad to populate
+		 * lvmcache, and just get the vg ids/names from lvmetad.
+		 */
+		lvmetad_get_vgnameids(cmd, include_internal, vgnameids_on_system);
 
-		dm_list_add(vgnameids_on_system, &vgnl->list);
+	} else {
+		/*
+		 * In the non-lvmetad case, this function begins by calling
+		 * lvmcache_label_scan() to populate lvmcache.
+		 */
+		lvmcache_get_vgnameids(cmd, include_internal, vgnameids_on_system);
 	}
 
 	return ECMD_PROCESSED;
@@ -2821,10 +2810,10 @@ int process_each_pv(struct cmd_context *cmd,
 	process_all_devices = process_all_pvs && (cmd->command->flags & ENABLE_ALL_DEVS) &&
 			      arg_count(cmd, all_ARG);
 
+
 	/*
-	 * Read all the vgs here because this has the effect of initializing
-	 * device/lvmcache info so that dev->pvid is available when creating
-	 * a list of devices.
+	 * Read all the vgs here to populate the device/lvmcache info,
+	 * so that dev->pvid is available when creating a list of devices.
 	 */
 	if ((ret = _get_vgnameids_on_system(cmd, &all_vgnameids, only_this_vgname, 1) != ECMD_PROCESSED)) {
 		stack;