[PATCH v2 08/16] monitor: add option --cleanup / -C

[mwilck at suse.com]

From: Martin Wilck <mwilck at suse.com>

With this option, "nvme monitor" will remove created discovery controllers
after it exits. To avoid shutting down connections that were created
independently, check existing connections on startup and track them with
the discovery_ctrl_existed flag.
---
 conn-db.c |  1 +
 conn-db.h |  1 +
 monitor.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/conn-db.c b/conn-db.c
index cfdc208..93eae4a 100644
--- a/conn-db.c
+++ b/conn-db.c
@@ -382,6 +382,7 @@ int conndb_init_from_sysfs(void)
 			instance =ctrl_instance(devices[i]->d_name);
 			if (instance >= 0) {
 				ci->c.discovery_instance = instance;
+				ci->c.discovery_ctrl_existed = 1;
 				msg(LOG_DEBUG, "found discovery controller %s\n",
 				    devices[i]->d_name);
 			}
diff --git a/conn-db.h b/conn-db.h
index e2a5827..8f5b400 100644
--- a/conn-db.h
+++ b/conn-db.h
@@ -12,6 +12,7 @@ struct nvme_connection {
 	int discovery_pending:1;
 	int did_discovery:1;
 	int successful_discovery:1;
+	int discovery_ctrl_existed:1;
 	union {
 		pid_t discovery_task;
 		int discovery_result;
diff --git a/monitor.c b/monitor.c
index b17fca0..e7e91f9 100644
--- a/monitor.c
+++ b/monitor.c
@@ -43,8 +43,10 @@
 
 static struct monitor_config {
 	bool autoconnect;
+	bool keep_ctrls;
 } mon_cfg = {
 	.autoconnect = true,
+	.keep_ctrls = true,
 };
 
 static struct dispatcher *mon_dsp;
@@ -499,15 +501,50 @@ static int monitor_kill_discovery_task(struct nvme_connection *co,
 	}
 }
 
+static int monitor_remove_discovery_ctrl(struct nvme_connection *co,
+					void *arg __attribute__((unused)))
+{
+	char syspath[PATH_MAX];
+	int len;
+	char *subsysnqn __cleanup__(cleanup_charp) = NULL;
+
+	if (co->discovery_instance == -1 || co->discovery_ctrl_existed)
+		return CD_CB_OK;
+
+	len = snprintf(syspath, sizeof(syspath), SYS_NVME "/nvme%d",
+		       co->discovery_instance);
+	if (len < 0 || len >= sizeof(syspath))
+		return CD_CB_ERR;
+
+	subsysnqn = nvme_get_ctrl_attr(syspath, "subsysnqn");
+	if (subsysnqn && !strcmp(subsysnqn, NVME_DISC_SUBSYS_NAME)) {
+		if (remove_ctrl(co->discovery_instance)) {
+			msg(LOG_ERR,
+			    "failed to remove discovery controller /dev/nvme%d: %m\n",
+			    co->discovery_instance);
+			return CD_CB_ERR;
+		} else
+			msg(LOG_INFO,
+			    "removed discovery controller /dev/nvme%d\n",
+			    co->discovery_instance);
+	} else
+		msg(LOG_WARNING,
+		    "unexpected NQN %s on /dev/nvme%d, not removing controller\n",
+		    subsysnqn ? subsysnqn : "(NULL)", co->discovery_instance);
+	return CD_CB_OK;
+}
+
 static int monitor_parse_opts(const char *desc, int argc, char **argv)
 {
 	bool quiet = false;
 	bool verbose = false;
 	bool debug = false;
 	bool noauto = false;
+	bool cleanup = false;
 	int ret;
 	OPT_ARGS(opts) = {
 		OPT_FLAG("no-connect",     'N', &noauto,              "dry run, do not autoconnect to discovered controllers"),
+		OPT_FLAG("cleanup",        'C', &cleanup,                     "remove created discovery controllers on exit"),
 		OPT_LIST("hostnqn",        'q', &fabrics_cfg.hostnqn,         "user-defined hostnqn (if default not used)"),
 		OPT_LIST("hostid",         'I', &fabrics_cfg.hostid,          "user-defined hostid (if default not used)"),
 		OPT_INT("keep-alive-tmo",  'k', &fabrics_cfg.keep_alive_tmo,  "keep alive timeout period in seconds"),
@@ -540,6 +577,8 @@ static int monitor_parse_opts(const char *desc, int argc, char **argv)
 		log_level = LOG_DEBUG;
 	if (noauto)
 		mon_cfg.autoconnect = false;
+	if (cleanup)
+		mon_cfg.keep_ctrls = false;
 
 	return ret;
 }
@@ -604,9 +643,12 @@ int aen_monitor(const char *desc, int argc, char **argv)
 		goto out;
 	}
 
+	conndb_init_from_sysfs();
 	ret = event_loop(mon_dsp, &wait_mask, handle_epoll_err);
 
 	conndb_for_each(monitor_kill_discovery_task, NULL);
+	if (mon_cfg.autoconnect && !mon_cfg.keep_ctrls)
+		conndb_for_each(monitor_remove_discovery_ctrl, NULL);
 	conndb_free();
 out:
 	free_dispatcher(mon_dsp);
-- 
2.29.2