From mboxrd@z Thu Jan 1 00:00:00 1970 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=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 BBB09C433DB for ; Mon, 15 Feb 2021 03:32:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8107264E5E for ; Mon, 15 Feb 2021 03:32:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229836AbhBODcM (ORCPT ); Sun, 14 Feb 2021 22:32:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229829AbhBODcK (ORCPT ); Sun, 14 Feb 2021 22:32:10 -0500 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DEE69C061574 for ; Sun, 14 Feb 2021 19:31:29 -0800 (PST) Received: by mail-pf1-x42b.google.com with SMTP id m6so3389908pfk.1 for ; Sun, 14 Feb 2021 19:31:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=uGee1Sqxh09dV8vkHRwclJsUep7f7elSEGwb7r92uZM=; b=pMZRPm8cdpq3GcVV5SDtobk8F9OheAbYTKyEDYitF0QmZDXfi6oU6zRwlv7eiGgBSh Me4X3zKbVocZrB3i/SGkbl4ifvBbJfeEG+/cysE+N+ocenj34bP296YwAdyyBCJeUtz9 8CGClmncU+4n6MpMkRt/xV68du7s2u2YHrpxuJR356NX5mXg9vdkFZflEqM4hxGoabEm avmuBPR65AYEnOW0v7Ey50/DMN0AgGqX3HctU4YwsIs+hk322EnJ8lMjfpY86wlpk7A3 WU44ZJ4HCcigJKK/WVj7IWR8ALIs3RNE8BXb+FWZ5ODyjkGd6bdCnvyxl3UT2KgS/0gW RtNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=uGee1Sqxh09dV8vkHRwclJsUep7f7elSEGwb7r92uZM=; b=D6vzsyWX5qvxgsfJekVvUd/Zq6l4ZAIMR65+E82DeHoTJA9my5i8yZ9x6+nWDWs0UV cGre0mjLKv+6BjrehUlbvM5RvV4ca/o7PaHVbOMnFS05s5l6UJw2w6OrFkMTmzNgO91r 1/841YEzr5g+45J+p6MtqJaednNl7n94n9VMbIarErPfZGCQDW9/oUC/fpRr+F8tmxTL 02Igl2pYnD08lfpJeI6t/eiulcVtyoETf5gknJ9a8zHWzXm6DHNJ61tWBtvMq+w380TH 1WPJeCJ09TI7X6M5VAPDr7ZROwZ/teb0jQBVIGPjVJyhnInJ+l3BXC4V/65TBG0LzCab aWSg== X-Gm-Message-State: AOAM533TrLUxTwjnqhRHvyfbNp4puJXV76dCzqmpx85nRKX+YQtZQm/X f7UEq1gHI0aYoWBkZ8i3q7/5uB5k3PoY4Q== X-Google-Smtp-Source: ABdhPJxQGBImz1c71eRCcr+c0r2VMSqsNlE1XnUx5xnHp69PpA4EkU/fNFi0Ej5WharSBU3FFAaaLA== X-Received: by 2002:a62:3852:0:b029:1da:7238:1cb1 with SMTP id f79-20020a6238520000b02901da72381cb1mr13722320pfa.11.1613359889195; Sun, 14 Feb 2021 19:31:29 -0800 (PST) Received: from [192.168.1.134] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id y73sm16687963pfb.17.2021.02.14.19.31.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 14 Feb 2021 19:31:28 -0800 (PST) Subject: Re: [PATCH RFC] namei: don't drop link paths acquired under LOOKUP_RCU To: Al Viro Cc: linux-fsdevel References: <8b114189-e943-a7e6-3d31-16aa8a148da6@kernel.dk> <0699912b-84ae-39d5-6b2e-8cb04eaa3939@kernel.dk> From: Jens Axboe Message-ID: <8b364ddb-cf9a-bf32-d426-053ff3aa6385@kernel.dk> Date: Sun, 14 Feb 2021 20:31:28 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 2/14/21 3:57 PM, Al Viro wrote: > On Sun, Feb 14, 2021 at 09:45:39AM -0700, Jens Axboe wrote: > >>>> +out3: >>>> + nd->depth = 0; // as we hadn't gotten to legitimize_links() >>>> out2: >>>> nd->path.mnt = NULL; >>>> out1: >>> >>> Alternatively, we could use the fact that legitimize_links() is not >>> called anywhere other than these two places and have LOOKUP_CACHED >>> checked there. As in >> >> Both fix the issue for me, just tested them. The second one seems >> cleaner to me, would probably be nice to have a comment on that in >> either the two callers or at least in legitimize_links() though. > > Hmm... Do you have anything on top of that branch? If you do, there's > no way to avoid leaving bisect hazard; if not, I'd rather fold a fix > into the broken commit... I do, that's basically the base of that series, -rc6 + that branch. So I'd prefer if you just apply the fixup, which I do think is pretty low risk even if it is a potential bisection pain point. But not really a huge one, in this case. That said, if you do want to rebase it, I can rebase mine. That's not the end of the world either. -- Jens Axboe