From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lf1-f41.google.com (mail-lf1-f41.google.com [209.85.167.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84FAF27EED for ; Mon, 18 Sep 2023 19:59:37 +0000 (UTC) Received: by mail-lf1-f41.google.com with SMTP id 2adb3069b0e04-502153ae36cso7904698e87.3 for ; Mon, 18 Sep 2023 12:59:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; t=1695067175; x=1695671975; darn=lists.linux.dev; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=IfqbVkGHBoZGHryAINIdEudRrkAyBzkbimgGl4E0yt8=; b=cncbjGFl2rLoHeUnqyNOrngMQuGCrqFsi1maVBXdDwERSwAL4Ad3wK/6wloJVBPzKz eSAchNNnqEo/vetW3397xVyfeBUNDGUiUcnaztVg/ZKKWgAAXD4x9WvWRwbyl0udACYa UUdGF4IxHUiMXEmpMZhHZhNReMjG0uqXgP1AM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695067175; x=1695671975; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=IfqbVkGHBoZGHryAINIdEudRrkAyBzkbimgGl4E0yt8=; b=bf6V8MixjqC8xlqVdhgM8uPfnjlWIP2x7+CicwJuB4/UDqMnTNC5bz4cQQPdJYGrEP 7c6FJ6SvbzCkOLfG5deJW35ZP4G5hecMaSNoFQ68pOa44cUt9nH7xfUZFHO+InLSZUlw jY1LsGqqKCfu14+r57kb37WqauKR7XWujkIXMo0r3LQ5JUqjvhhhcCn7jx1Md/EgwJA7 SBCdAcZ1T1CVOpyF24HbgkwK3xCrKHWnK5TfN2D+jTI2qL+nhjK2RlqQo6vwJHRcoYQz zOifR9OfBfIfUjeKQND437uPAAkHWj8N2aDEoYt0wWw8jMMoteYTPy5aro9Ej4B4mPdT 7L1Q== X-Gm-Message-State: AOJu0Yzypvx4tY2bTWj96tfy7eB0Y2f8r1gBfBesNy9M/hJDy0sPbFVI YZ41vYYPvKehWzojAYgrm4a7CrptkWK4+8SPW6WvxHZk X-Google-Smtp-Source: AGHT+IFD3aTUV4TuAhKMj0RaJY2rzVT/WK5x5gRc2dZ3aslrsjd0bQZG2TojxzVoqkXwC3CbZQMKmw== X-Received: by 2002:a05:6512:2393:b0:502:fd08:69f7 with SMTP id c19-20020a056512239300b00502fd0869f7mr9092311lfv.28.1695067175047; Mon, 18 Sep 2023 12:59:35 -0700 (PDT) Received: from mail-lf1-f49.google.com (mail-lf1-f49.google.com. [209.85.167.49]) by smtp.gmail.com with ESMTPSA id w14-20020ac2598e000000b004ff8631d6c0sm1941069lfn.278.2023.09.18.12.59.33 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Sep 2023 12:59:34 -0700 (PDT) Received: by mail-lf1-f49.google.com with SMTP id 2adb3069b0e04-500a8b2b73eso7943240e87.0 for ; Mon, 18 Sep 2023 12:59:33 -0700 (PDT) X-Received: by 2002:a19:8c0b:0:b0:503:99d:5a97 with SMTP id o11-20020a198c0b000000b00503099d5a97mr4098028lfd.20.1695067173515; Mon, 18 Sep 2023 12:59:33 -0700 (PDT) Precedence: bulk X-Mailing-List: ksummit@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20230907071801.1d37a3c5@gandalf.local.home> <169491481677.8274.17867378561711132366@noble.neil.brown.name> <20230917185742.GA19642@mit.edu> <20230918111402.7mx3wiecqt5axvs5@quack3> In-Reply-To: From: Linus Torvalds Date: Mon, 18 Sep 2023 12:59:15 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [MAINTAINERS/KERNEL SUMMIT] Trust and maintenance of file systems To: Jiri Kosina Cc: Jan Kara , "Theodore Ts'o" , NeilBrown , James Bottomley , Dave Chinner , Eric Sandeen , Steven Rostedt , Guenter Roeck , Christoph Hellwig , ksummit@lists.linux.dev, linux-fsdevel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" On Mon, 18 Sept 2023 at 12:32, Jiri Kosina wrote: > > I am afraid this is not reflecting reality. > > I am pretty sure that "give me that document on a USB stick, and I'll take > a look" leads to using things like libreoffice (or any other editor liked > by general public) to open the file directly on the FAT USB stick. And > that's pretty much guaranteed to use mmap(). Ugh. I would have hoped that anybody will fall back to read/write - because we definitely have filesystems that don't support mmap. But I guess they are so specialized as to not ever trigger that kind of problem (eg /proc - nobody is putting office documents there ;) A cache-incoherent MAP_PRIVATE only mmap (ie one that doesn't react to 'write()' changing the data) is easy to do, but yeah, it would still be a lot more work than just "keep things as-is". Linus