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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS autolearn=ham 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 C255EC43219 for ; Fri, 26 Apr 2019 16:36:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F28E208CA for ; Fri, 26 Apr 2019 16:36:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556296584; bh=j5VmV0LTqlo0cJ5wg0tlMwL1js3aQ2hrIi+wcItV89Y=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=ps+KXKupqXpJSJ+jqeEj/Kcs+6BTHbBIXQRc1bIguMyOxOxTWm3OD6mkFvbhqA3j2 hNmXCg0soypiPH1BjLm1yyNVG+FzLPfTSH4rqtZTGXYN0N45PRH20tvCIebnoIrA1n jviFs/EZl8WTjR9pcIu0B9KjVEVEhclW78F9clPQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726315AbfDZQgX (ORCPT ); Fri, 26 Apr 2019 12:36:23 -0400 Received: from mail-lj1-f194.google.com ([209.85.208.194]:37732 "EHLO mail-lj1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726181AbfDZQgV (ORCPT ); Fri, 26 Apr 2019 12:36:21 -0400 Received: by mail-lj1-f194.google.com with SMTP id b12so2310172lji.4 for ; Fri, 26 Apr 2019 09:36:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=DEdb/dXXS4BmabuVj7tMWOPVyS6P8uPlgXYLftrG0EE=; b=h75dC+nGCj4qVfVP3NHHhRACGt5wq2lEMV1zHeI3Kn4urKTnUOrgSoQytgde9qbpVM GiVmB9UUGvPuXqMHWTcMf1b+bF9oQArQw9zod389zdpwyU1eUVhD4roCfLsmJb6m6f36 V9ftvlpDloxCg9bY8bUbqmhGa1yeP8oFSSIzA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=DEdb/dXXS4BmabuVj7tMWOPVyS6P8uPlgXYLftrG0EE=; b=CCsHPzO8gSZ4k0r8hfUD9sbj7gR3CC3ZoBZOGXt3F90IEi3mj9GlOp15JcDvl35ZLO JQIKiylhKIvckYksZScA8peUuhTvYV3TFd/YWgyLZizhsZ2DzRsZtz5TN+Ab49j73aM5 fPSGEvA07itvZgbIN7qTfc8bSCXVfgXWpckaJwsF65NfBI9I32XwIZGGNqgkPdpLvuu8 xeC+xJ3/x01I71664q7u7vqSiCck2ktoq+tu7vMK1nYlKZS4LPb9bkBU0LcGx3mae6A8 3yfZJFBSEek63tHaKWf53HccaCP++bHzSGSwG82Xj15EHq+OQkNX0NgqDlyxew+bMRCE r0NQ== X-Gm-Message-State: APjAAAWaXJvxVsdxkqCOurw7eb9H4hdixU/TwRIFpcjtJ2zw263kIj8M fG6C6co6QumUc/g5jAhjQsYCmQm4qd8= X-Google-Smtp-Source: APXvYqwBxkx4UTN1GqiB2bvT7XxUfhEeWbSVEPa8ZgmO8NE/o5kpi1C9JkOHcyLp5hJiC9mdv041jw== X-Received: by 2002:a2e:7a09:: with SMTP id v9mr24209284ljc.167.1556296578355; Fri, 26 Apr 2019 09:36:18 -0700 (PDT) Received: from mail-lj1-f174.google.com (mail-lj1-f174.google.com. [209.85.208.174]) by smtp.gmail.com with ESMTPSA id p11sm2862203lfh.27.2019.04.26.09.36.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 26 Apr 2019 09:36:17 -0700 (PDT) Received: by mail-lj1-f174.google.com with SMTP id q10so3487707ljc.6 for ; Fri, 26 Apr 2019 09:36:17 -0700 (PDT) X-Received: by 2002:a2e:960b:: with SMTP id v11mr24952343ljh.135.1556296576721; Fri, 26 Apr 2019 09:36:16 -0700 (PDT) MIME-Version: 1.0 References: <20190425174739.27604-1-idryomov@gmail.com> <342ef35feb1110197108068d10e518742823a210.camel@kernel.org> <20190425200941.GW2217@ZenIV.linux.org.uk> <86674e79e9f24e81feda75bc3c0dd4215604ffa5.camel@kernel.org> In-Reply-To: <86674e79e9f24e81feda75bc3c0dd4215604ffa5.camel@kernel.org> From: Linus Torvalds Date: Fri, 26 Apr 2019 09:36:00 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [GIT PULL] Ceph fixes for 5.1-rc7 To: Jeff Layton Cc: Al Viro , Ilya Dryomov , ceph-devel@vger.kernel.org, Linux List Kernel Mailing Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 26, 2019 at 9:25 AM Jeff Layton wrote: > > Is it really ok to union the count and rcu_head there? It should be fine, because the rcu_count should only ever be used once the count has gone to zero and the name cannot be found any more. And while RCU path walking may find and use the *name* after the dentry has been killed off (but not free'd yet), all the actual external_name() accesses should be serialized by the dentry lock, so there's no access to those fields once the dentry is dead. At least that's how it's supposed to work. Al would be the final arbiter on this. Linus