Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753823AbdGPOSO (ORCPT ); Sun, 16 Jul 2017 10:18:14 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:44392 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753796AbdGPOSI (ORCPT ); Sun, 16 Jul 2017 10:18:08 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jonathan Liu" , "Sachin Prabhu" , "Steve French" , "Pavel Shilovsky" Date: Sun, 16 Jul 2017 14:56:46 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 155/178] cifs: Do not send echoes before Negotiate is complete In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2174 Lines: 63 3.16.46-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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: Ben Hutchings --- fs/cifs/smb1ops.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/fs/cifs/smb1ops.c +++ b/fs/cifs/smb1ops.c @@ -1015,6 +1015,15 @@ cifs_dir_needs_close(struct cifsFileInfo 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, @@ -1048,6 +1057,7 @@ struct smb_version_operations smb1_opera .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,