From 47849daf73c1978491c05e9619063ff8a529ca48 Mon Sep 17 00:00:00 2001
From: Tang Chen <tang.chen@huawei.com>
Date: Thu, 12 Oct 2017 04:56:16 +0800
Subject: [PATCH 1/1] iscsid: Check nr_sessions when creating a copy of
 existing session

For multipath configurations, you may want more than one session to be
created on each iface record.  If node.session.nr_sessions is greater
than 1, performing a 'login' for that node will ensure that the
appropriate number of sessions is created.

        node.session.nr_sessions = 1

In iscsiadm command, we set session.multiple to 1, which means we can
create multiple copies of an existing session.

iscsi_login_portal()
|--> rec->session.multiple = 1

But in iscsid, we didn't check nr_sessions when executing login task.

__session_login_task()
|--> session_is_running()
         |--> iscsi_sysfs_for_each_session()
|--> if (rec->session.multiple)
                 log_debug(2, "Adding a copy of an existing session");

So this patch adds a checking to iscsid login task.

Signed-off-by: Tang Chen <tang.chen@huawei.com>

---
 usr/initiator.c | 31 ++++++++++++++++++-------------
 1 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/usr/initiator.c b/usr/initiator.c
index a86d1e6..9248962 100644
--- a/usr/initiator.c
+++ b/usr/initiator.c
@@ -1754,10 +1754,11 @@ static int iscsi_sched_ev_context(struct iscsi_ev_context *ev_context,
 	return 0;
 }
 
-static iscsi_session_t* session_find_by_rec(node_rec_t *rec)
+static int session_find_by_rec(node_rec_t *rec)
 {
 	struct iscsi_transport *t;
 	iscsi_session_t *session;
+	int nr_found = 0;
 
 	list_for_each_entry(t, &transports, list) {
 		list_for_each_entry(session, &t->sessions, list) {
@@ -1766,24 +1767,23 @@ static iscsi_session_t* session_find_by_rec(node_rec_t *rec)
 					 session->nrec.conn[0].port,
 					 &session->nrec.iface,
 					 MATCH_ANY_SID))
-				return session;
+				nr_found++;
 		}
 	}
-	return NULL;
+	return nr_found;
 }
 
 /*
  * a session could be running in the kernel but not in iscsid
  * due to a resync or because some other app started the session
  */
-static int session_is_running(node_rec_t *rec)
+static int session_is_running(node_rec_t *rec, int *nr_found)
 {
-	int nr_found = 0;
-
-	if (session_find_by_rec(rec))
+	*nr_found = session_find_by_rec(rec);
+	if (*nr_found)
 		return 1;
 
-	if (iscsi_sysfs_for_each_session(rec, &nr_found, iscsi_match_session,
+	if (iscsi_sysfs_for_each_session(rec, nr_found, iscsi_match_session,
 					 0))
 		return 1;
 
@@ -1795,12 +1795,17 @@ static int __session_login_task(node_rec_t *rec, queue_task_t *qtask)
 	iscsi_session_t *session;
 	iscsi_conn_t *conn;
 	struct iscsi_transport *t;
-	int rc;
-
-	if (session_is_running(rec)) {
-		if (rec->session.multiple)
+	int rc, nr_found = 0;
+
+	if (session_is_running(rec, &nr_found)) {
+		if (rec->session.multiple) {
+			if (nr_found >= rec->session.nr_sessions) {
+				log_debug(2, "Cannot add more copy of session,"
+						" %d found.\n", nr_found);
+				return ISCSI_ERR_SESS_EXISTS;
+			}
 			log_debug(2, "Adding a copy of an existing session");
-		else
+		} else
 			return ISCSI_ERR_SESS_EXISTS;
 	}
 
-- 
1.8.3.1