From patchwork Fri May 8 12:35:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 226193 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21DE2C47257 for ; Fri, 8 May 2020 12:57:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9AEF2054F for ; Fri, 8 May 2020 12:57:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588942653; bh=b2QdKOeAuXxVphJVniePs7dMgcY5GW7kcKW3nlDsHuM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=o62Aep4wchgo3C5sX/stepNXP6bj9rdEwENWIH+ghpWznM8P/XHKKrXH818dnfVdG xyDmj0FfhksBMpc6oCygDxSs5aoWKu9LPatlFgeBb+VlWzuPYytSEh38F5xMUzZww7 y0aKBET6fb0+DegtwJTf2qOjfDv/6hCGcxUo72/A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727891AbgEHMzg (ORCPT ); Fri, 8 May 2020 08:55:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:38520 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730027AbgEHMza (ORCPT ); Fri, 8 May 2020 08:55:30 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C3B97218AC; Fri, 8 May 2020 12:55:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588942530; bh=b2QdKOeAuXxVphJVniePs7dMgcY5GW7kcKW3nlDsHuM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KfdBPA/dvoYkcqTRvqU1fJikcbFaIO774aAE1ul2eZQPSQV3cpVqkdAHXVcCtyl1G zwRgOdJKIRDLRALhKT7A+nuqWY7aliULH3nAxDU7dTo1rS8STCmztAMSr/smiIkNMd kLa1JxH5MPfNtvKmWFdzXtUrNifgE1Bjj4QZP2oE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Paulo Alcantara (SUSE)" , Aurelien Aptel , Ronnie Sahlberg , Steve French , Sasha Levin Subject: [PATCH 5.6 32/49] cifs: do not share tcons with DFS Date: Fri, 8 May 2020 14:35:49 +0200 Message-Id: <20200508123047.448817393@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200508123042.775047422@linuxfoundation.org> References: <20200508123042.775047422@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paulo Alcantara [ Upstream commit 65303de829dd6d291a4947c1a31de31896f8a060 ] This disables tcon re-use for DFS shares. tcon->dfs_path stores the path that the tcon should connect to when doing failing over. If that tcon is used multiple times e.g. 2 mounts using it with different prefixpath, each will need a different dfs_path but there is only one tcon. The other solution would be to split the tcon in 2 tcons during failover but that is much harder. tcons could not be shared with DFS in cifs.ko because in a DFS namespace like: //domain/dfsroot -> /serverA/dfsroot, /serverB/dfsroot //serverA/dfsroot/link -> /serverA/target1/aa/bb //serverA/dfsroot/link2 -> /serverA/target1/cc/dd you can see that link and link2 are two DFS links that both resolve to the same target share (/serverA/target1), so cifs.ko will only contain a single tcon for both link and link2. The problem with that is, if we (auto)mount "link" and "link2", cifs.ko will only contain a single tcon for both DFS links so we couldn't perform failover or refresh the DFS cache for both links because tcon->dfs_path was set to either "link" or "link2", but not both -- which is wrong. Signed-off-by: Paulo Alcantara (SUSE) Reviewed-by: Aurelien Aptel Reviewed-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/cifs/connect.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index d4a23b48e24d8..9c614d6916c2d 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -3419,6 +3419,10 @@ cifs_find_tcon(struct cifs_ses *ses, struct smb_vol *volume_info) spin_lock(&cifs_tcp_ses_lock); list_for_each(tmp, &ses->tcon_list) { tcon = list_entry(tmp, struct cifs_tcon, tcon_list); +#ifdef CONFIG_CIFS_DFS_UPCALL + if (tcon->dfs_path) + continue; +#endif if (!match_tcon(tcon, volume_info)) continue; ++tcon->tc_count;