From 55937f9c8e01a6274964a939c85c19f9785e27ce Mon Sep 17 00:00:00 2001
From: Zdenek Kabelac <zkabelac@redhat.com>
Date: Mon, 19 Feb 2024 14:13:20 +0100
Subject: [PATCH] vdo: read VDO stats via dm message

As the sysfs interface is seen somewhat obsolete, swith code
to prefer using DM 'stats' message to get our currently needed
info for VDO pool target.
---
 lib/activate/dev_manager.c       | 57 ++++++++++++++++++++++++++++++++
 lib/metadata/metadata-exported.h |  5 +--
 lib/metadata/vdo_manip.c         | 10 +++---
 3 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/lib/activate/dev_manager.c b/lib/activate/dev_manager.c
index 9b1dcd250..4da2a0ad7 100644
--- a/lib/activate/dev_manager.c
+++ b/lib/activate/dev_manager.c
@@ -1905,6 +1905,60 @@ out:
 	return r;
 }
 
+/* Read info from DM VDO 'stats' message */
+static int _dev_manager_vdo_pool_message_stats(struct dev_manager *dm,
+					       const struct logical_volume *lv,
+					       struct lv_status_vdo *status)
+{
+	const char *response;
+	const char *dlid;
+	struct dm_task *dmt = NULL;
+	int r = 0;
+	unsigned i;
+	const char *p;
+	struct vdo_msg_elem {
+		const char *name;
+		uint64_t *val;
+	} const vme[] = {
+		{ "dataBlocksUsed", &status->data_blocks_used },
+		{ "logicalBlocksUsed", &status->logical_blocks_used }
+	};
+
+	if (!(dlid = build_dm_uuid(dm->mem, lv, lv_layer(lv))))
+		return_0;
+
+	if (!(dmt = _setup_task_run(DM_DEVICE_TARGET_MSG, NULL, NULL, dlid, 0, 0, 0, 0, 0, 0)))
+		return_0;
+
+	if (!dm_task_set_message(dmt, "stats"))
+		goto_out;
+
+	if (!dm_task_run(dmt))
+		goto_out;
+
+	log_debug_activation("Checking VDO pool stats message for LV %s.",
+			     display_lvname(lv));
+
+	if ((response = dm_task_get_message_response(dmt))) {
+		for (i = 0; i < DM_ARRAY_SIZE(vme); ++i) {
+			errno = 0;
+			if (!(p = strstr(response,  vme[i].name)) ||
+			    !(p = strchr(p, ':')) ||
+			    ((*vme[i].val = strtoul(p + 1, NULL, 10)) == ULLONG_MAX) || errno) {
+				log_debug("Cannot parse %s in VDO DM stats message.", vme[i].name);
+				*vme[i].val = 0;
+				goto out;
+			}
+		}
+	}
+
+	r = 1;
+out:
+	dm_task_destroy(dmt);
+
+	return r;
+}
+
 int dev_manager_vdo_pool_status(struct dev_manager *dm,
 				const struct logical_volume *lv, int flush,
 				struct lv_status_vdo **status, int *exists)
@@ -1945,6 +1999,9 @@ int dev_manager_vdo_pool_status(struct dev_manager *dm,
 		goto out;
 	}
 
+	if (!_dev_manager_vdo_pool_message_stats(dm, lv, *status))
+		stack;
+
 	if (!parse_vdo_pool_status(dm->mem, lv, params, &info, *status))
 		goto_out;
 
diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
index 8c7bd4583..c9825799b 100644
--- a/lib/metadata/metadata-exported.h
+++ b/lib/metadata/metadata-exported.h
@@ -1380,8 +1380,9 @@ int wipe_cache_pool(struct logical_volume *cache_pool_lv);
 struct lv_status_vdo {
 	struct dm_pool *mem;
 	struct dm_vdo_status *vdo;
-	uint64_t data_blocks_used;	/* grabbed from /sys/kvdo */
-	uint64_t logical_blocks_used;	/* grabbed from /sys/kvdo */
+	/* grabbed from DM stats message, /sys/block/dm-/vdo or /sys/kvdo */
+	uint64_t data_blocks_used;
+	uint64_t logical_blocks_used;
 	dm_percent_t usage;
 	dm_percent_t saving;
 	dm_percent_t data_usage;
diff --git a/lib/metadata/vdo_manip.c b/lib/metadata/vdo_manip.c
index c8eebe55a..1ee39c6d7 100644
--- a/lib/metadata/vdo_manip.c
+++ b/lib/metadata/vdo_manip.c
@@ -217,10 +217,12 @@ int parse_vdo_pool_status(struct dm_pool *mem, const struct logical_volume *vdo_
 	status->vdo = result.status;
 
 	if ((result.status->operating_mode == DM_VDO_MODE_NORMAL) &&
-	    _sysfs_get_kvdo_value(dm_name, dminfo, "statistics/data_blocks_used",
-				  &status->data_blocks_used) &&
-	    _sysfs_get_kvdo_value(dm_name, dminfo, "statistics/logical_blocks_used",
-				  &status->logical_blocks_used)) {
+            (status->data_blocks_used ||
+	     _sysfs_get_kvdo_value(dm_name, dminfo, "statistics/data_blocks_used",
+				   &status->data_blocks_used)) &&
+	    (status->logical_blocks_used ||
+	     _sysfs_get_kvdo_value(dm_name, dminfo, "statistics/logical_blocks_used",
+				   &status->logical_blocks_used))) {
 		status->usage = dm_make_percent(result.status->used_blocks,
 						result.status->total_blocks);
 		status->saving = dm_make_percent(status->logical_blocks_used - status->data_blocks_used,
-- 
2.43.5