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=-3.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 05C27C43387 for ; Tue, 15 Jan 2019 08:48:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C827220656 for ; Tue, 15 Jan 2019 08:48:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nrz07DuP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728491AbfAOIsi (ORCPT ); Tue, 15 Jan 2019 03:48:38 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:34932 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728351AbfAOIsh (ORCPT ); Tue, 15 Jan 2019 03:48:37 -0500 Received: by mail-wm1-f66.google.com with SMTP id t200so2317238wmt.0; Tue, 15 Jan 2019 00:48:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=YNQM8SbAvD4caqNlRyJ+lsvlBhcfmgqwWM2paM5xmDI=; b=nrz07DuPB/NHFFWP/XRyRp7h/NuGuSE/uAFDh52iZNqRRBCFwrOomBF5t30+ysPBaS GgMoYhOt+05ojFiY1Im6VTyQahSJ8q3Bsse6HhhEGd5WPt0DLHLUN/tdqUA0j8HQV/W4 MRTNlHUHBG0mnaZSAEM6uOKer3KG7EyG99UEjqrPDnCmnWUxW6yWKNGsXBepsWaxMfUT jljPCuA2F+mnzJUQBsvzasfVvvzB4cFEtfIbMDDecbHNSe+X4KAuW3/Ih9MVvprhJNq/ x6qhNMYvGLf9JAzCb4wlJJy6bnwplqe6yGHBwkfSUE+Vsk3FYUi5QumLASSkuzet6Pfd ptyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=YNQM8SbAvD4caqNlRyJ+lsvlBhcfmgqwWM2paM5xmDI=; b=HfzUwqVMJE7sPbZpKUXv7+0gZBEY6vx5KBJrCd6S24li8zd8nU1koLMGU0yBoOiSWQ t17fiE5GuyXjEKDgJhD1JrjPVCNs+EaVpbwnwdAx19N1R00DvMjM+gvaoA70U2bpP1Nf yJr+GfKO4MrKxFO6RIxB+P8/Lpr5Kg3K0nJ7oflbLSNRWhJCyvTBmiyOclcZC8GzKH2i +vxdbDRW6q56qiWxjtWOCm+lZ1xpBXYVuplh09eeE26Uf59LSHm3a/4wizOfANGNvlYQ XkhUrcP+sPslN8cZQFBN9x4VXBeflB7sicMMGtT/3goJG/wIHXrrzt9+WNysPNHVvYQi oijg== X-Gm-Message-State: AJcUukcq509AyqFwDovsXLsG5YvOjl7V23wY1/oxk2TM8KiRynxb/u1f sy0ZVo35hwFIKY35vuDlIAI= X-Google-Smtp-Source: ALg8bN6TeYFPkFwlRdIjDm6G1fy021qD9FXoLVke94GWrIbo3f2qibeUSyBMVfdaO/Jj8OIy49BUZw== X-Received: by 2002:a1c:e913:: with SMTP id q19mr2420767wmc.55.1547542114407; Tue, 15 Jan 2019 00:48:34 -0800 (PST) Received: from pali ([2a02:2b88:2:1::5cc6:2f]) by smtp.gmail.com with ESMTPSA id q12sm21204265wmf.2.2019.01.15.00.48.33 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 15 Jan 2019 00:48:33 -0800 (PST) Date: Tue, 15 Jan 2019 09:48:32 +0100 From: Pali =?utf-8?B?Um9ow6Fy?= To: Jan Kara Cc: Michael Sabolish , Kevin Weidemann , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: udf: Prevent write-unsupported filesystem to be remounted read-write Message-ID: <20190115084832.fypbuhyvgfizh3am@pali> References: <124cc6ea-ca79-20f2-651e-c2f909729ac0@gmx.de> <8cf39b7c-505b-91e6-849d-e66ba980042f@postn.eu> <20190114103011.GD13316@quack2.suse.cz> <20190114120023.wkftfz6pwatehpfe@pali> <20190114123042.GH13316@quack2.suse.cz> <20190115083111.qq2mt2p2kn4opwx7@pali> <20190115084119.GE29524@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190115084119.GE29524@quack2.suse.cz> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 15 January 2019 09:41:19 Jan Kara wrote: > On Tue 15-01-19 09:31:11, Pali Rohár wrote: > > On Monday 14 January 2019 19:07:35 Michael Sabolish wrote: > > > I can try and make a pull-request for udftune, and I can just copy the API for tune2fs. It would work something like: > > > > > > udftune -O read-only device (to set read-only access type) > > > > > > or: > > > > > > udftune -O ^read-only device (to clear read-only access type (aka set rw)) > > > > This API is ambiguous. What does it mean for ^read-only? In UDF you have > > following access types: overwritable, rewritable, writeonce, readonly, > > pseudo-overwritable, unknown. > > > > So you would need to know to which R/W access type to switch > > (overwritable, rewritable, writeonce or pseudo-overwritable). > > > > With information of media type, you could be able to guess correct > > access type. But for UDF images stored in VFS there is no media > > information. Also you can have uncommon setup, e.g. usage of CD-R > > writeonce setup on CD-R/W disc. So "autodetection" of media type would > > not work always correctly. > > > > So I think that it would be better to have following API: > > > > udftune --access-type= > > > > or > > > > udftune --change-access-type= > > > > I understand that you would like to have similar API as tune2fs, but UDF > > settings are too different from ext*. > > If you wanted to follow tune2fs interface, you can have e.g.: Question is if it is a good idea to follow this interface. > udftune -E access-type= > > Another question about the feature is - the access type is actually per > partition and there can be multiple partitions on UDF media. So I think we > need to specify the partition number in the command and has to > actually be something like ,. Access type is stored in partition descriptor and in UDF (as opposite of ECMA-167) you can have only one partition descriptor. IIRC there is some exception when you have two partition descriptors, but then one have to be readonly and second virtual. -- Pali Rohár pali.rohar@gmail.com