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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 037B1C63697 for ; Tue, 17 Nov 2020 18:30:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A525E2462E for ; Tue, 17 Nov 2020 18:30:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="T1lLpoJM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730347AbgKQS3y (ORCPT ); Tue, 17 Nov 2020 13:29:54 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:39525 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727552AbgKQS3y (ORCPT ); Tue, 17 Nov 2020 13:29:54 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605637787; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=n+sA9RW4IaMrLL5m5pqRfekzWZqlArjiOjWWeiCtFB4=; b=T1lLpoJMvfYPFUNql9ZdwLPAy7dYegES4mRmYzdr2JbBIWk7hzAA/UxkWaSE6lWPTJKI7n c5y2cGca8nMBLnYqPjiYKM94rscPOlpMjSXaOlBf/cAagGLuB2DmGnoVu4EBz6/L0VfbP8 nQ4tyor7cUpncg/PgLIFhJ+r9kI8ZxA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-563-Cv_DgJ4pPIqspP4wf8EJZw-1; Tue, 17 Nov 2020 13:29:43 -0500 X-MC-Unique: Cv_DgJ4pPIqspP4wf8EJZw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 720BB809DE4; Tue, 17 Nov 2020 18:29:41 +0000 (UTC) Received: from horse.redhat.com (ovpn-116-186.rdu2.redhat.com [10.10.116.186]) by smtp.corp.redhat.com (Postfix) with ESMTP id 077F419931; Tue, 17 Nov 2020 18:29:41 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 4314B220BCF; Tue, 17 Nov 2020 13:29:40 -0500 (EST) Date: Tue, 17 Nov 2020 13:29:40 -0500 From: Vivek Goyal To: Amir Goldstein Cc: Sargun Dhillon , overlayfs , Miklos Szeredi , Alexander Viro , Giuseppe Scrivano , Daniel J Walsh , David Howells , linux-fsdevel , Chengguang Xu Subject: Re: [RFC PATCH 3/3] overlay: Add the ability to remount volatile directories when safe Message-ID: <20201117182940.GA91497@redhat.com> References: <20201116144240.GA9190@redhat.com> <20201116163615.GA17680@redhat.com> <20201116210950.GD9190@redhat.com> <20201117144857.GA78221@redhat.com> <20201117164600.GC78221@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Nov 17, 2020 at 08:03:16PM +0200, Amir Goldstein wrote: > > > C. "shutdown" the filesystem if writeback errors happened and return > > > EIO from any read, like some blockdev filesystems will do in face > > > of metadata write errors > > > > > > I happen to have a branch ready for that ;-) > > > https://github.com/amir73il/linux/commits/ovl-shutdown > > > > > > This branch seems to implement shutdown ioctl. So it will still need > > glue code to detect writeback failure in upper/ and trigger shutdown > > internally? > > > > Yes. > ovl_get_acess() can check both the administrative ofs->goingdown > command and the upper writeback error condition for volatile ovl > or something like that. This approach will not help mmaped() pages though, if I do. - Store to addr - msync - Load from addr There is a chance that I can still read back old data. > > > And if that works, then Sargun's patches can fit in nicely on top which > > detect writeback failures on remount and will shutdown fs. > > > > Not sure why remount needs to shutdown. It needs to fail mount, > but yeh, all those things should fit nicely together. Agreed. mount/remount can just fail in that case. Thanks Vivek