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[209.85.128.47]) by smtp.gmail.com with ESMTPSA id u5-20020a170906068500b00703671ebe65sm14581791ejb.198.2022.07.04.13.51.43 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 04 Jul 2022 13:51:43 -0700 (PDT) Received: by mail-wm1-f47.google.com with SMTP id l40-20020a05600c1d2800b003a18adff308so6346217wms.5 for ; Mon, 04 Jul 2022 13:51:43 -0700 (PDT) X-Received: by 2002:a05:600c:354e:b0:3a1:9ddf:468d with SMTP id i14-20020a05600c354e00b003a19ddf468dmr9623331wmq.145.1656967892746; Mon, 04 Jul 2022 13:51:32 -0700 (PDT) MIME-Version: 1.0 References: <20220701142310.2188015-1-glider@google.com> <20220701142310.2188015-44-glider@google.com> In-Reply-To: From: Linus Torvalds Date: Mon, 4 Jul 2022 13:51:16 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v4 43/45] namei: initialize parameters passed to step_into() To: Al Viro Cc: Alexander Potapenko , Alexei Starovoitov , Andrew Morton , Andrey Konovalov , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Christoph Hellwig , Christoph Lameter , David Rientjes , Dmitry Vyukov , Eric Dumazet , Greg Kroah-Hartman , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jens Axboe , Joonsoo Kim , Kees Cook , Marco Elver , Mark Rutland , Matthew Wilcox , "Michael S. Tsirkin" , Pekka Enberg , Peter Zijlstra , Petr Mladek , Steven Rostedt , Thomas Gleixner , Vasily Gorbik , Vegard Nossum , Vlastimil Babka , kasan-dev , Linux-MM , linux-arch , Linux Kernel Mailing List , Evgenii Stepanov , Nathan Chancellor , Nick Desaulniers , Segher Boessenkool , Vitaly Buka , linux-toolchains Content-Type: text/plain; charset="UTF-8" ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656967906; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=D+7oxHi4Udb60oAybVQkpA6ge9KpdkDRHq2SyT5frGM=; b=MlmnvKKwrWco4wn4Fn5V/eErCZBNXkkqVxy4Si6+Yrh+uL0xsA3zOSNZ13XOHFL8HoY32B 7lF9xFA5K0ZCI/YvWYSjJbOmEdwMQN+8amIdQZp7CYv1Yar+cuzRbMEZLRnqZXo1gJHc+N jln78DcuhGwG3Dn1IJmQiqMFtNFrx3c= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=WC8Na+ue; dmarc=none; spf=pass (imf15.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.218.48 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656967906; a=rsa-sha256; cv=none; b=nSVd+fwgREtyX/+hzkEui7bsXpJWkmsM/6bn6akTptzULikHoZzrrM/byQjUqF39GG2gI0 6rWAg+WuOFNUP1QpDwfG4W6dCe1+n7DdQZESnobFbuVbSOBaaWBg05mO81BOEe6QyRkrWn Po1/DXJwWgFvOMf4wrCv72uxba656zg= X-Rspam-User: X-Rspamd-Queue-Id: 01C90A0015 Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=WC8Na+ue; dmarc=none; spf=pass (imf15.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.218.48 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org X-Stat-Signature: 7wcz9qyu84n4siffag3n5on6ca53fsmd X-Rspamd-Server: rspam08 X-HE-Tag: 1656967905-94794 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jul 4, 2022 at 1:46 PM Al Viro wrote: > > Why is that a problem? It could have been moved to another parent, > but so it could after we'd crossed to the mounted and we wouldn't have > noticed (or cared). Yeah, see my other email. I agree that it might be a "we don't actually care" situation, where all we care about that the name was valid at one point (when we picked up that sequence point). So maybe we don't care about closing it. But even if so, I think it might warrant a comment, because I still feel like we're basically "throwing away" our previous sequence point information without ever checking it. Maybe all we ever care about is basically "this sequence point protects the dentry inode pointer for the next lookup", and when it comes to mount points that ends up being immaterial. Linus