Call echo service immediately after socket reconnect

BugLink: http://bugs.launchpad.net/bugs/1669941

Commit 4fcd1813 ("Fix reconnect to not defer smb3 session reconnect
long after socket reconnect") changes the behaviour of the SMB2 echo
service and causes it to renegotiate after a socket reconnect. However
under default settings, the echo service could take up to 120 seconds to
be scheduled.

The patch forces the echo service to be called immediately resulting a
negotiate call being made immediately on reconnect.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
(back ported from commit b8c60012)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

Conflicts:
	fs/cifs/connect.c
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

fs/cifs/connect.c

@@ -412,6 +412,9 @@ cifs_reconnect(struct TCP_Server_Info *server)
 		}
 	} while (server->tcpStatus == CifsNeedReconnect);
 
+	if (server->tcpStatus == CifsNeedNegotiate)
+		mod_delayed_work(cifsiod_wq, &server->echo, 0);
+
 	return rc;
 }
 
@@ -421,18 +424,27 @@ cifs_echo_request(struct work_struct *work)
 	int rc;
 	struct TCP_Server_Info *server = container_of(work,
 					struct TCP_Server_Info, echo.work);
+	unsigned long echo_interval;
+
+	/*
+	 * If we need to renegotiate, set echo interval to zero to
+	 * immediately call echo service where we can renegotiate.
+	 */
+	if (server->tcpStatus == CifsNeedNegotiate)
+		echo_interval = 0;
+	else
+		echo_interval = SMB_ECHO_INTERVAL;
 
 	/*
-	 * We cannot send an echo if it is disabled or until the
-	 * NEGOTIATE_PROTOCOL request is done, which is indicated by
-	 * server->ops->need_neg() == true. Also, no need to ping if
-	 * we got a response recently.
+	 * We cannot send an echo if it is disabled.
+	 * Also, no need to ping if we got a response recently.
 	 */
 
 	if (server->tcpStatus == CifsNeedReconnect ||
-	    server->tcpStatus == CifsExiting || server->tcpStatus == CifsNew ||
+	    server->tcpStatus == CifsExiting ||
+	    server->tcpStatus == CifsNew ||
 	    (server->ops->can_echo && !server->ops->can_echo(server)) ||
-	    time_before(jiffies, server->lstrp + SMB_ECHO_INTERVAL - HZ))
+	    time_before(jiffies, server->lstrp + echo_interval - HZ))
 		goto requeue_echo;
 
 	rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;