lvmetad: clear the disabled flag in lvmetad

After a device rescan that repopulates lvmetad,
if no reason for disabling lvmetad was seen
(lvm1 metadata or duplicate PVs), then clear
the disabled flag in lvmetad.  This allows
commands to resume using the lvmetad cache
after the cause for disabling it has been removed.

2 files changed, 39 insertions, 0 deletions

diff --git a/lib/cache/lvmetad.c b/lib/cache/lvmetad.c
index 0f79da7fb..890110ed4 100644
--- a/lib/cache/lvmetad.c
+++ b/lib/cache/lvmetad.c
@@ -37,6 +37,8 @@ static char *_lvmetad_token = NULL;
 static const char *_lvmetad_socket = NULL;
 static struct cmd_context *_lvmetad_cmd = NULL;
 
+static int _found_lvm1_metadata = 0;
+
 static struct volume_group *lvmetad_pvscan_vg(struct cmd_context *cmd, struct volume_group *vg);
 
 static int _log_debug_inequality(const char *name, struct dm_config_node *a, struct dm_config_node *b)
@@ -1541,6 +1543,7 @@ static struct volume_group *lvmetad_pvscan_vg(struct cmd_context *cmd, struct vo
 			lvmcache_fmt(info)->ops->destroy_instance(baton.fid);
 			log_warn("WARNING: Disabling lvmetad cache which does not support obsolete metadata.");
 			lvmetad_set_disabled(cmd, "LVM1");
+			_found_lvm1_metadata = 1;
 			return NULL;
 		}
 
@@ -1657,6 +1660,7 @@ int lvmetad_pvscan_single(struct cmd_context *cmd, struct device *dev,
 
 		log_warn("WARNING: Disabling lvmetad cache which does not support obsolete metadata.");
 		lvmetad_set_disabled(cmd, "LVM1");
+		_found_lvm1_metadata = 1;
 
 		if (ignore_obsolete)
 			return 1;
@@ -1732,6 +1736,7 @@ static int _lvmetad_pvscan_all_devs(struct cmd_context *cmd, activation_handler
 	daemon_reply reply;
 	int r = 1;
 	char *future_token;
+	const char *reason;
 	int was_silent;
 	int replacing_other_update = 0;
 	int replaced_update = 0;
@@ -1808,6 +1813,16 @@ static int _lvmetad_pvscan_all_devs(struct cmd_context *cmd, activation_handler
 	if (!_token_update(NULL))
 		return 0;
 
+	/*
+	 * If lvmetad is disabled, and no lvm1 metadata was seen and no
+	 * duplicate PVs were seen, then re-enable lvmetad.
+	 */
+	if (lvmetad_is_disabled(cmd, &reason) &&
+	    !lvmcache_found_duplicate_pvs() && !_found_lvm1_metadata) {
+		log_debug_lvmetad("Enabling lvmetad which was previously disabled.");
+		lvmetad_clear_disabled(cmd);
+	}
+
 	return r;
 }
 
@@ -2213,6 +2228,28 @@ void lvmetad_set_disabled(struct cmd_context *cmd, const char *reason)
 	daemon_reply_destroy(reply);
 }
 
+void lvmetad_clear_disabled(struct cmd_context *cmd)
+{
+	daemon_reply reply;
+
+	if (!_lvmetad_use)
+		return;
+
+	log_debug_lvmetad("lvmetad send disabled 0");
+
+	reply = daemon_send_simple(_lvmetad, "set_global_info",
+				   "token = %s", "skip",
+				   "global_disable = " FMTd64, (int64_t)0,
+				   NULL);
+	if (reply.error)
+		log_error("Failed to send message to lvmetad %d", reply.error);
+
+	if (strcmp(daemon_reply_str(reply, "response", ""), "OK"))
+		log_error("Failed response from lvmetad.");
+
+	daemon_reply_destroy(reply);
+}
+
 int lvmetad_is_disabled(struct cmd_context *cmd, const char **reason)
 {
 	daemon_reply reply;
diff --git a/lib/cache/lvmetad.h b/lib/cache/lvmetad.h
index 76e8fd266..9ae3f2645 100644
--- a/lib/cache/lvmetad.h
+++ b/lib/cache/lvmetad.h
@@ -174,6 +174,7 @@ int lvmetad_vg_is_foreign(struct cmd_context *cmd, const char *vgname, const cha
 
 int lvmetad_is_disabled(struct cmd_context *cmd, const char **reason);
 void lvmetad_set_disabled(struct cmd_context *cmd, const char *reason);
+void lvmetad_clear_disabled(struct cmd_context *cmd);
 
 #  else		/* LVMETAD_SUPPORT */
 
@@ -207,6 +208,7 @@ void lvmetad_set_disabled(struct cmd_context *cmd, const char *reason);
 #    define lvmetad_token_matches(cmd) (1)
 #    define lvmetad_is_disabled(cmd, reason) (0)
 #    define lvmetad_set_disabled(cmd, reason) do { } while (0)
+#    define lvmetad_clear_disabled(cmd) do { } while (0)
 
 #  endif	/* LVMETAD_SUPPORT */