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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 27FD2C49EA5 for ; Tue, 22 Jun 2021 15:10:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EADE6128E for ; Tue, 22 Jun 2021 15:10:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232101AbhFVPMo (ORCPT ); Tue, 22 Jun 2021 11:12:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232102AbhFVPMe (ORCPT ); Tue, 22 Jun 2021 11:12:34 -0400 Received: from mail-vs1-xe2c.google.com (mail-vs1-xe2c.google.com [IPv6:2607:f8b0:4864:20::e2c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E46F4C061760 for ; Tue, 22 Jun 2021 08:10:16 -0700 (PDT) Received: by mail-vs1-xe2c.google.com with SMTP id j8so11437914vsd.0 for ; Tue, 22 Jun 2021 08:10:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szeredi.hu; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=o6jYECB1uY4kERwbwvQK62eKjskNIcvHqO/SelbLP+4=; b=pAN82221DIsUtrhb0p19lThHLu2emVpyjnLMrwRYEYMDXMZmJmomO2VGncVefPqeLk PnDv1mRg1xC4M0pPQpPSCfRUjwORrNe8KO6RCkK4uVhwO535jnc00YuKndimXSYZwRrL 1qYgII3/HAmV7OjzDGHqcVLo+eR9flvdOJ94w= 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:content-transfer-encoding; bh=o6jYECB1uY4kERwbwvQK62eKjskNIcvHqO/SelbLP+4=; b=qN147L1Lh7zlx9P5ul9Fr2gS/ZJ6HPVtQF9P71s6NWsxY/CDPLNWgEteuKBSDruRLO ATawitbmNz5Fk57WnTCHqbSM53Iin3k60mUMASmgbfWUajzIBBEiSBIrz2Prfw45euPN 3yR1AeOWXzzWyIHJl4A6fXTNCZwzqIXc8nu80Qosrie9O8oKFFwg5lqQKBV2XwRYGuNb sNQpAG0gXiEB9CcAuI1rKrJDAD5hLJPvlL8JGzyOUuH/xaMuPmOEQtQhmAbsfYaGDKd5 1Ym/cUWcCQ57o7ldkHnrTtSTX4kXopV6f6ZqvnBI/XaMQrhVoeZg1g/goMOD0mLxxsCl m/8g== X-Gm-Message-State: AOAM531jHhDA8swi48wmBL7slqOmKZiOpPGeoN1z8jX5fMusztv3v0Qn iKcjdPtoag3+/8aV3xabGV4esPwJTJJYp0WSJtKX1Q== X-Google-Smtp-Source: ABdhPJzX7TH0X2nUVdZbCqZU8+z232mRwthdahvJ7HHQQYRERYGZF4uBl6yHl06y7O/o8Q4PJiqE+3iLP0fzGCmWnEM= X-Received: by 2002:a67:bb14:: with SMTP id m20mr23694461vsn.0.1624374616050; Tue, 22 Jun 2021 08:10:16 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Miklos Szeredi Date: Tue, 22 Jun 2021 17:10:05 +0200 Message-ID: Subject: Re: [PATCH] ovl: fix mmap denywrite To: =?UTF-8?Q?Christian_K=C3=B6nig?= Cc: linux-fsdevel@vger.kernel.org, linux-mm , Chengguang Xu , overlayfs Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, 22 Jun 2021 at 14:43, Christian K=C3=B6nig wrote: > > Am 22.06.21 um 14:30 schrieb Miklos Szeredi: > > Overlayfs did not honor positive i_writecount on realfile for VM_DENYWR= ITE > > mappings. Similarly negative i_mmap_writable counts were ignored for > > VM_SHARED mappings. > > > > Fix by making vma_set_file() switch the temporary counts obtained and > > released by mmap_region(). > > Mhm, I don't fully understand the background but that looks like > something specific to overlayfs to me. > > So why are you changing the common helper? Need to hold the temporary counts until the final ones are obtained in vma_link(), which is out of overlayfs' scope. Thanks, Miklos