linux-kernel - [PATCH 3.18 03/32] Call echo service immediately after socket reconnect

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Date:   Mon, 19 Jun 2017 23:20:47 +0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sachin Prabhu <sprabhu@...hat.com>,
        Pavel Shilovsky <pshilov@...rosoft.com>,
        Steve French <smfrench@...il.com>
Subject: [PATCH 3.18 03/32] Call echo service immediately after socket reconnect

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sachin Prabhu <sprabhu@...hat.com>

commit b8c600120fc87d53642476f48c8055b38d6e14c7 upstream.

Commit 4fcd1813e640 ("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@...hat.com>
Reviewed-by: Pavel Shilovsky <pshilov@...rosoft.com>
Signed-off-by: Steve French <smfrench@...il.com>
Acked-by: Sachin Prabhu <sprabhu@...hat.com>
Signed-off-by: Pavel Shilovsky <pshilov@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/cifs/connect.c |   24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -400,6 +400,9 @@ cifs_reconnect(struct TCP_Server_Info *s
 		mutex_unlock(&server->srv_mutex);
 	} while (server->tcpStatus == CifsNeedReconnect);
 
+	if (server->tcpStatus == CifsNeedNegotiate)
+		mod_delayed_work(cifsiod_wq, &server->echo, 0);
+
 	return rc;
 }
 
@@ -409,18 +412,27 @@ cifs_echo_request(struct work_struct *wo
 	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;