[PATCH 7/7] libiscsi: reset max/exp cmdsn during recovery

From: Mike Christie <michael.christie@oracle.com>
To: lduncan@suse.com, cleech@redhat.com, martin.petersen@oracle.com,
	linux-scsi@vger.kernel.org,
	james.bottomley@hansenpartnership.com
Cc: lutianxiong@huawei.com, linfeilong@huawei.com,
	liuzhiqiang26@huawei.com, haowenchao@huawei.com
Subject: [PATCH 7/7] libiscsi: reset max/exp cmdsn during recovery
Date: Mon, 18 Jan 2021 14:34:30 -0600	[thread overview]
Message-ID: <20210118203430.4921-8-michael.christie@oracle.com> (raw)
In-Reply-To: <20210118203430.4921-1-michael.christie@oracle.com>

If we lose the session then relogin, but the new cmdsn window has
shrunk (due to something like an admin changing a setting) we will
have the old exp/max_cmdsn values and will never be able to update
them. For example, max_cmdsn would be 64, but if on the target the
user set the window to be smaller then the target could try to return
the max_cmdsn as 32. We will see that new max_cmdsn in the rsp but
because it's lower than the old max_cmdsn when the window was larger
we will not update it.

So this patch has us reset the windown values during session
cleanup so they can be updated after a new login.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
---
 drivers/scsi/libiscsi.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 195006a08e0d..be29837372c2 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -3271,6 +3271,13 @@ int iscsi_conn_bind(struct iscsi_cls_session *cls_session,
 		session->leadconn = conn;
 	spin_unlock_bh(&session->frwd_lock);
 
+	/*
+	 * The target could have reduced it's window size between logins, so
+	 * we have to reset max/exp cmdsn so we can see the new values.
+	 */
+	spin_lock_bh(&session->back_lock);
+	session->max_cmdsn = session->exp_cmdsn = session->cmdsn + 1;
+	spin_unlock_bh(&session->back_lock);
 	/*
 	 * Unblock xmitworker(), Login Phase will pass through.
 	 */
-- 
2.25.1

