Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752800AbdFSTje (ORCPT + 2 others); Mon, 19 Jun 2017 15:39:34 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:51802 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750947AbdFSSeT (ORCPT ); Mon, 19 Jun 2017 14:34:19 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Sachin Prabhu , Steve French , Willy Tarreau Subject: [PATCH 3.10 026/268] cifs: Do not send echoes before Negotiate is complete Date: Mon, 19 Jun 2017 20:28:45 +0200 Message-Id: <1497897167-14556-27-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1497897167-14556-1-git-send-email-w@1wt.eu> References: <1497897167-14556-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Sachin Prabhu commit 62a6cfddcc0a5313e7da3e8311ba16226fe0ac10 upstream. commit 4fcd1813e640 ("Fix reconnect to not defer smb3 session reconnect long after socket reconnect") added support for Negotiate requests to be initiated by echo calls. To avoid delays in calling echo after a reconnect, I added the patch introduced by the commit b8c600120fc8 ("Call echo service immediately after socket reconnect"). This has however caused a regression with cifs shares which do not have support for echo calls to trigger Negotiate requests. On connections which need to call Negotiation, the echo calls trigger an error which triggers a reconnect which in turn triggers another echo call. This results in a loop which is only broken when an operation is performed on the cifs share. For an idle share, it can DOS a server. The patch uses the smb_operation can_echo() for cifs so that it is called only if connection has been already been setup. kernel bz: 194531 Signed-off-by: Sachin Prabhu Tested-by: Jonathan Liu Acked-by: Pavel Shilovsky Signed-off-by: Steve French Signed-off-by: Willy Tarreau --- fs/cifs/smb1ops.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c index 610c6c2..d97841e 100644 --- a/fs/cifs/smb1ops.c +++ b/fs/cifs/smb1ops.c @@ -891,6 +891,15 @@ cifs_dir_needs_close(struct cifsFileInfo *cfile) return !cfile->srch_inf.endOfSearch && !cfile->invalidHandle; } +static bool +cifs_can_echo(struct TCP_Server_Info *server) +{ + if (server->tcpStatus == CifsGood) + return true; + + return false; +} + struct smb_version_operations smb1_operations = { .send_cancel = send_nt_cancel, .compare_fids = cifs_compare_fids, @@ -923,6 +932,7 @@ struct smb_version_operations smb1_operations = { .get_dfs_refer = CIFSGetDFSRefer, .qfs_tcon = cifs_qfs_tcon, .is_path_accessible = cifs_is_path_accessible, + .can_echo = cifs_can_echo, .query_path_info = cifs_query_path_info, .query_file_info = cifs_query_file_info, .get_srv_inum = cifs_get_srv_inum, -- 2.8.0.rc2.1.gbe9624a