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[209.85.221.41]) by smtp.gmail.com with ESMTPSA id i11sm1548963edu.97.2021.08.13.17.55.10 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 13 Aug 2021 17:55:11 -0700 (PDT) Received: by mail-wr1-f41.google.com with SMTP id q11so15487539wrr.9 for ; Fri, 13 Aug 2021 17:55:10 -0700 (PDT) X-Received: by 2002:a2e:81c2:: with SMTP id s2mr3500799ljg.48.1628902499779; Fri, 13 Aug 2021 17:54:59 -0700 (PDT) MIME-Version: 1.0 References: <20210812084348.6521-1-david@redhat.com> <87o8a2d0wf.fsf@disp2133> <60db2e61-6b00-44fa-b718-e4361fcc238c@www.fastmail.com> <87lf56bllc.fsf@disp2133> <87eeay8pqx.fsf@disp2133> <5b0d7c1e73ca43ef9ce6665fec6c4d7e@AcuMS.aculab.com> <87h7ft2j68.fsf@disp2133> In-Reply-To: From: Linus Torvalds Date: Fri, 13 Aug 2021 14:54:43 -1000 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v1 0/7] Remove in-tree usage of MAP_DENYWRITE To: Andy Lutomirski Cc: "Eric W. Biederman" , David Laight , David Hildenbrand , Linux Kernel Mailing List , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Al Viro , Alexey Dobriyan , Steven Rostedt , "Peter Zijlstra (Intel)" , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Petr Mladek , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Kees Cook , Greg Ungerer , Geert Uytterhoeven , Mike Rapoport , Vlastimil Babka , Vincenzo Frascino , Chinwen Chang , Michel Lespinasse , Catalin Marinas , "Matthew Wilcox (Oracle)" , Huang Ying , Jann Horn , Feng Tang , Kevin Brodsky , Michael Ellerman , Shawn Anastasio , Steven Price , Nicholas Piggin , Christian Brauner , Jens Axboe , Gabriel Krisman Bertazi , Peter Xu , Suren Baghdasaryan , Shakeel Butt , Marco Elver , Daniel Jordan , Nicolas Viennot , Thomas Cedeno , Collin Fijalkovich , Michal Hocko , Miklos Szeredi , Chengguang Xu , =?UTF-8?Q?Christian_K=C3=B6nig?= , "linux-unionfs@vger.kernel.org" , Linux API , "the arch/x86 maintainers" , "" , Linux-MM , Florian Weimer , Michael Kerrisk Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org On Fri, Aug 13, 2021 at 2:49 PM Andy Lutomirski wrote: > > I=E2=80=99ll bite. How about we attack this in the opposite direction: r= emove the deny write mechanism entirely. I think that would be ok, except I can see somebody relying on it. It's broken, it's stupid, but we've done that ETXTBUSY for a _loong_ time. But you are right that we have removed parts of it over time (no more MAP_DENYWRITE, no more uselib()) so that what we have today is a fairly weak form of what we used to do. And nobody really complained when we weakened it, so maybe removing it entirely might be acceptable. Linus