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=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 52242C388F9 for ; Wed, 11 Nov 2020 15:21:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC42E206B6 for ; Wed, 11 Nov 2020 15:21:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qYMfEdaH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727329AbgKKPVI (ORCPT ); Wed, 11 Nov 2020 10:21:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726720AbgKKPVI (ORCPT ); Wed, 11 Nov 2020 10:21:08 -0500 Received: from mail-io1-xd42.google.com (mail-io1-xd42.google.com [IPv6:2607:f8b0:4864:20::d42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38C89C0613D1; Wed, 11 Nov 2020 07:21:08 -0800 (PST) Received: by mail-io1-xd42.google.com with SMTP id n129so2646026iod.5; Wed, 11 Nov 2020 07:21:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=YdeSYPUdMsbv9Ht0DhrnvlWMZUneO0/r6IjX9uZ0U70=; b=qYMfEdaHlw20bKvfMAeD4DLUWMkOTE0sWJy/OIifD9zv4QDSCJRn/6u/4s7cti3EcR 3rYaS/lzi/IRgrAGLAUwrUhsOLKg7lspghF2SM3JSSEyMB3ak0znwBZAyJzoW3f1DGMG 969aQQrSz572F/oAQYzyY4+E8IJUJ7FrpfLQq2kl48rKtDzwpIGo1GFlP1/9RCMtRwIJ 0kFMOe8nuBUGWM8vcY2Qr1rxvzwmMfFN3nQwBPOraol9LVQgTVv4W6Yybe5fAoJUHJ58 8yH+LJ13gB/a9QS6YSWNpz5XMx1GvHm2lXGpeo+CmdFh8LrCspPsfEwL13iVsTg/uafs G+dA== 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=YdeSYPUdMsbv9Ht0DhrnvlWMZUneO0/r6IjX9uZ0U70=; b=a3jBG1JTB00ZhsUA8mW06I2C0e9xnpgy8zMWwxdRNJyjFwTkfBsZqT6ZFSYm79AENK VQX1IP/SKpLSgH+Q3d9QIX5vvTkji/v928VFdWKUlWHbEuWuvwGQBDbKBwPjRJ1NfKJu fKb/NyuoYjy7/Ai++WGdROAH8gNkDA1d92F35X/gdHJnCMVnFGkgWoYgIWj1saYWx1vn P1/nG+1D2Faxp8GAv6h5YnHTeMJ9uPGK5SMDaK4uTstqFKom6YmyOPkwg+bR6kNhgMEO 9RCXxtTb0vyxVx7CnmXRUXG0lbFUzMTMWFEVL6z+8TPBM8qqvrhGJGSvpa4VUH22xGD/ UvnQ== X-Gm-Message-State: AOAM533x6h6+j9fYXGKv2jWzZc/3epcN1CxLJrNlm7e7PfSfzz70FnB1 RXCto55Qsz8dBmcuLgwz/im5CRai2kHxlXhQuok= X-Google-Smtp-Source: ABdhPJwg3UGmNk92V3xFF9gjz/I4MLhhGJ6F2P5a4p3UJDw/wFSlsChK2RjdWLVSHooBH/4JpNo6LHnW6brBsCSC9SE= X-Received: by 2002:a02:70ce:: with SMTP id f197mr20807827jac.120.1605108067560; Wed, 11 Nov 2020 07:21:07 -0800 (PST) MIME-Version: 1.0 References: <20201108140307.1385745-1-cgxu519@mykernel.net> <20201108140307.1385745-7-cgxu519@mykernel.net> <175b769393e.da9339695127.2777354745619336639@mykernel.net> In-Reply-To: <175b769393e.da9339695127.2777354745619336639@mykernel.net> From: Amir Goldstein Date: Wed, 11 Nov 2020 17:20:56 +0200 Message-ID: Subject: Re: [RFC PATCH v3 06/10] ovl: mark overlayfs' inode dirty on shared mmap To: Chengguang Xu Cc: miklos , jack , linux-unionfs , linux-fsdevel 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 Wed, Nov 11, 2020 at 3:05 PM Chengguang Xu wrote: > > ---- =E5=9C=A8 =E6=98=9F=E6=9C=9F=E6=97=A5, 2020-11-08 22:03:03 Chenggua= ng Xu =E6=92=B0=E5=86=99 ---- > > Overlayfs cannot be notified when mmapped area gets dirty, > > so we need to proactively mark inode dirty in ->mmap operation. > > > > Signed-off-by: Chengguang Xu > > --- > > fs/overlayfs/file.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c > > index efccb7c1f9bc..662252047fff 100644 > > --- a/fs/overlayfs/file.c > > +++ b/fs/overlayfs/file.c > > @@ -486,6 +486,8 @@ static int ovl_mmap(struct file *file, struct vm_a= rea_struct *vma) > > /* Drop reference count from new vm_file value */ > > fput(realfile); > > } else { > > + if (vma->vm_flags & (VM_SHARED|VM_MAYSHARE)) > > Maybe it's better to mark dirty only having upper inode. > Yeh. And since mapping_map_writable() is only called if VM_SHARED flag is set (and not VM_MAYSHARE), we are not going to re-dirty an inode on account of VM_MAYSHARE alone, so I wonder why we need to mark it dirty here on account of VM_MAYSHARE? Thanks, Amir.