From patchwork Wed Nov 27 00:36:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paulo Alcantara X-Patchwork-Id: 1201260 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=cjr.nz Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; secure) header.d=cjr.nz header.i=@cjr.nz header.b="U8uCAmz9"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 47N20W1n6Kz9sSc for ; Wed, 27 Nov 2019 11:37:15 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726957AbfK0AhP (ORCPT ); Tue, 26 Nov 2019 19:37:15 -0500 Received: from mx.cjr.nz ([51.158.111.142]:16070 "EHLO mx.cjr.nz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726947AbfK0AhO (ORCPT ); Tue, 26 Nov 2019 19:37:14 -0500 Received: from authenticated-user (mx.cjr.nz [51.158.111.142]) (Authenticated sender: pc) by mx.cjr.nz (Postfix) with ESMTPSA id E176980A21; Wed, 27 Nov 2019 00:37:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cjr.nz; s=dkim; t=1574815032; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cwJx7z+bkC3/gD+ONb1P6E34ZBefqumUIraTyBEflQk=; b=U8uCAmz94aOO+s0XdNXJVFsCMmEX+RdAR/VLRVfYxeDv0zil+rEIzSX2jBmIQQV9qTDGIE 98DPQzst39LtwWvLYwvhcCI+sBdx485tKTJfpQY54lROb6rneEJgxtBAS2QW/ovmlKQynb UAkN5W+uPpWr954EbnRNaQIU1dEBxvJO5atWm2k5gGbnQeVCLnC846wjoBURfxP8cG6Pm8 CUYXZ7nK8AVfJF5H/u/fEHq1VMBMaAL4JMiXE9rvjIT6tQCd1NFVtp1aI1507r1msePd+F 3bHvjKpUWvb0rkaIVl8EjXxWhZyYIT83nptJHyNzBEds4MgwM0gRGRjSQxreUg== From: "Paulo Alcantara (SUSE)" To: smfrench@gmail.com Cc: linux-cifs@vger.kernel.org, "Paulo Alcantara (SUSE)" , Aurelien Aptel Subject: [PATCH v3 03/11] cifs: Fix potential softlockups while refreshing DFS cache Date: Tue, 26 Nov 2019 21:36:26 -0300 Message-Id: <20191127003634.14072-4-pc@cjr.nz> In-Reply-To: <20191127003634.14072-1-pc@cjr.nz> References: <20191127003634.14072-1-pc@cjr.nz> MIME-Version: 1.0 Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org We used to skip reconnects on all SMB2_IOCTL commands due to SMB3+ FSCTL_VALIDATE_NEGOTIATE_INFO - which made sense since we're still establishing a SMB session. However, when refresh_cache_worker() calls smb2_get_dfs_refer() and we're under reconnect, SMB2_ioctl() will not be able to get a proper status error (e.g. -EHOSTDOWN in case we failed to reconnect) but an -EAGAIN from cifs_send_recv() thus looping forever in refresh_cache_worker(). Signed-off-by: Paulo Alcantara (SUSE) Suggested-by: Aurelien Aptel Fixes: e99c63e4d86d ("SMB3: Fix deadlock in validate negotiate hits reconnect") Reviewed-by: Aurelien Aptel --- fs/cifs/smb2pdu.c | 41 +++++++++++++++++++++++++++++------------ 1 file changed, 29 insertions(+), 12 deletions(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index c09ca6963394..3cd90088d8ac 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -252,7 +252,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon) if (tcon == NULL) return 0; - if (smb2_command == SMB2_TREE_CONNECT || smb2_command == SMB2_IOCTL) + if (smb2_command == SMB2_TREE_CONNECT) return 0; if (tcon->tidStatus == CifsExiting) { @@ -426,16 +426,9 @@ fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon, void *buf, * SMB information in the SMB header. If the return code is zero, this * function must have filled in request_buf pointer. */ -static int -smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon, - void **request_buf, unsigned int *total_len) +static int __smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon, + void **request_buf, unsigned int *total_len) { - int rc; - - rc = smb2_reconnect(smb2_command, tcon); - if (rc) - return rc; - /* BB eventually switch this to SMB2 specific small buf size */ if (smb2_command == SMB2_SET_INFO) *request_buf = cifs_buf_get(); @@ -456,7 +449,31 @@ smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon, cifs_stats_inc(&tcon->num_smbs_sent); } - return rc; + return 0; +} + +static int smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon, + void **request_buf, unsigned int *total_len) +{ + int rc; + + rc = smb2_reconnect(smb2_command, tcon); + if (rc) + return rc; + + return __smb2_plain_req_init(smb2_command, tcon, request_buf, + total_len); +} + +static int smb2_ioctl_req_init(u32 opcode, struct cifs_tcon *tcon, + void **request_buf, unsigned int *total_len) +{ + /* Skip reconnect only for FSCTL_VALIDATE_NEGOTIATE_INFO IOCTLs */ + if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO) { + return __smb2_plain_req_init(SMB2_IOCTL, tcon, request_buf, + total_len); + } + return smb2_plain_req_init(SMB2_IOCTL, tcon, request_buf, total_len); } /* For explanation of negotiate contexts see MS-SMB2 section 2.2.3.1 */ @@ -2686,7 +2703,7 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst, int rc; char *in_data_buf; - rc = smb2_plain_req_init(SMB2_IOCTL, tcon, (void **) &req, &total_len); + rc = smb2_ioctl_req_init(opcode, tcon, (void **) &req, &total_len); if (rc) return rc;