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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 31F17C4361A for ; Sat, 5 Dec 2020 21:07:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E27F0230F9 for ; Sat, 5 Dec 2020 21:07:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727233AbgLEVH6 (ORCPT ); Sat, 5 Dec 2020 16:07:58 -0500 Received: from sender2-op-o12.zoho.com.cn ([163.53.93.243]:17142 "EHLO sender2-op-o12.zoho.com.cn" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725996AbgLEVH5 (ORCPT ); Sat, 5 Dec 2020 16:07:57 -0500 ARC-Seal: i=1; a=rsa-sha256; t=1607173756; cv=none; d=zoho.com.cn; s=zohoarc; b=Fa5o5qvaV3+NAcvHEK9/sD7Gt2+TEJvCTssVhm9qwqM1/SAM0cfg27F7uQxp9rTZvAlZsM0BwRZ4rqCe2bQ8XKUk4M07cCVNkiZuiO19/66yXuyj8qBdXi8j5NHWVwq1N56OVD/RTv+ob5CV4jSi/jFUI9N78+YFsWadJqGyMYY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com.cn; s=zohoarc; t=1607173756; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:MIME-Version:Message-ID:Subject:To; bh=tHxG5co5xvuUjGQ5Eh70UR6wHrLHoiLCPbQX5DiQRrY=; b=GudFEi8NTdFPYfbPhjgU4Q63vwdxmupFNfTfoX62CpVWhfqa+p6kaSKC++MGzsSoEi2hMo3DxMIYxAVKtEQict5IKF2S+jv58bo5tE6WLHWs4LDQt2gL9s47Hg1eRaRgSdy3lO4UOqc0XLyGfaOzs+zHNz+Rbxxx3SB0tBJEmpI= ARC-Authentication-Results: i=1; mx.zoho.com.cn; dkim=pass header.i=mykernel.net; spf=pass smtp.mailfrom=cgxu519@mykernel.net; dmarc=pass header.from= header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1607173756; s=zohomail; d=mykernel.net; i=cgxu519@mykernel.net; h=From:To:Cc:Message-ID:Subject:Date:MIME-Version:Content-Transfer-Encoding:Content-Type; bh=tHxG5co5xvuUjGQ5Eh70UR6wHrLHoiLCPbQX5DiQRrY=; b=ZcjEWzaY6FIh68kUQhmOmpeB9GXZcBzOvKzuBjgx7FnyJm56OVzoQ6tG32JMqvDx 5HoqCnpjq/7g2IKUHIzJnjlRA8GXnUyTa4CxYsQOBQErUjj6m6DcZthn9v8z0KozTTW FJAsJu0Kzaz+DxmHH0R9j3ZZOoeM+KlfyBOZsO1o= Received: from localhost.localdomain (113.87.90.239 [113.87.90.239]) by mx.zoho.com.cn with SMTPS id 1607173753136251.15710636560402; Sat, 5 Dec 2020 21:09:13 +0800 (CST) From: Chengguang Xu To: ericvh@gmail.com, lucho@ionkov.net, asmadeus@codewreck.org Cc: v9fs-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chengguang Xu Message-ID: <20201205130904.518104-1-cgxu519@mykernel.net> Subject: [RFC PATCH] 9p: create writeback fid on shared mmap Date: Sat, 5 Dec 2020 21:09:04 +0800 X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoCNMailClient: External Content-Type: text/plain; charset=utf8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If vma is shared and the file was opened for writing, we should also create writeback fid because vma may be mprotected writable even if now readonly. Signed-off-by: Chengguang Xu --- Caveat: Only compile tested. fs/9p/vfs_file.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index b177fd3b1eb3..791839c2dd5c 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -516,8 +516,7 @@ v9fs_mmap_file_mmap(struct file *filp, struct vm_area_s= truct *vma) =09v9inode =3D V9FS_I(inode); =09mutex_lock(&v9inode->v_mutex); =09if (!v9inode->writeback_fid && -=09 (vma->vm_flags & VM_SHARED) && -=09 (vma->vm_flags & VM_WRITE)) { +=09 mapping_writably_mapped(filp->f_mapping)) { =09=09/* =09=09 * clone a fid and add it to writeback_fid =09=09 * we do it during mmap instead of --=20 2.26.2