CIFS: reconnect thread reschedule itself

commit 18ea4311 upstream.

In case of error, smb2_reconnect_server reschedule itself
with a delay, to avoid being too aggressive.
Signed-off-by: Germano Percossi <germano.percossi@citrix.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/cifs/smb2pdu.c

@@ -1987,6 +1987,9 @@ void smb2_reconnect_server(struct work_struct *work)
 	struct cifs_tcon *tcon, *tcon2;
 	struct list_head tmp_list;
 	int tcon_exist = false;
+	int rc;
+	int resched = false;
+
 
 	/* Prevent simultaneous reconnects that can corrupt tcon->rlist list */
 	mutex_lock(&server->reconnect_mutex);
@@ -2014,13 +2017,18 @@ void smb2_reconnect_server(struct work_struct *work)
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	list_for_each_entry_safe(tcon, tcon2, &tmp_list, rlist) {
-		if (!smb2_reconnect(SMB2_INTERNAL_CMD, tcon))
+		rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon);
+		if (!rc)
 			cifs_reopen_persistent_handles(tcon);
+		else
+			resched = true;
 		list_del_init(&tcon->rlist);
 		cifs_put_tcon(tcon);
 	}
 
 	cifs_dbg(FYI, "Reconnecting tcons finished\n");
+	if (resched)
+		queue_delayed_work(cifsiod_wq, &server->reconnect, 2 * HZ);
 	mutex_unlock(&server->reconnect_mutex);
 
 	/* now we can safely release srv struct */