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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 7A9C6C33CA2 for ; Sun, 12 Jan 2020 14:47:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4812F214D8 for ; Sun, 12 Jan 2020 14:47:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nq1th4/E" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733036AbgALOrj (ORCPT ); Sun, 12 Jan 2020 09:47:39 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:33126 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733034AbgALOrj (ORCPT ); Sun, 12 Jan 2020 09:47:39 -0500 Received: by mail-wm1-f66.google.com with SMTP id d139so7894115wmd.0 for ; Sun, 12 Jan 2020 06:47:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:subject:message-id:mime-version:content-disposition :user-agent; bh=dOrsfyRmVgTXeGGW9Jq1FNHFR+dST2yOx0HfkK9Pv9s=; b=nq1th4/EZ7RZCYAlPJrkHqD7LESMDyoQNHLoo+akNy+AedheFwUDfIDakSj06YcCjt KwXEAS7XiisqhShYW0X0k0F7gS6O7aycvbfyZeL+P0WSaLI9zvm6BBAPEawIWuKpptSK j2hWFPZ/7BYEassdGdtDonbH1yRhQgww04EzTeX4pB3Anw7Cq4/3JesuSS2R4qFvgqgZ D5OpcAxqeWMGIL6QTZqX7jLsAy51+Hr5p1oo8P87SrsOnHsBfCOuDCsXfKPTqj6vsI3l ftHDArV384+c2P8ADT9Io0e7acJpfJVvr2ADJoQt4N1CM9ayf0uu0L7pQkGJ7qJc+uxa TROw== 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:subject:message-id:mime-version :content-disposition:user-agent; bh=dOrsfyRmVgTXeGGW9Jq1FNHFR+dST2yOx0HfkK9Pv9s=; b=aprrTth3DYmdFKiuHDdHNRUNc4nTXCxruu3v8ZAWJgtEJCZ+n/NVUZFDTsozFIgbMX pCwmMBYfwhU/vzoXwNUc+3TWPpuKlPPMarbX720KjmzaslgkpvJqTtXt07LxKiLEJRVw 9G7XgKfYYgdh/QNdpEAeFByCSgTcj29GhMM0aYlscSpidLcSCB8bvI3ORuaZU5LQ+NtE B3FgWLjRWFy9IUbPOhXZ47+bFRgVW3ztvkYsJygleomE+GbPs5I1Ox+1yMrQy6zx5jQ3 V0ftE03BR2qKGRjZalGmAnbFscRtu7yiL8WQCKnA6LS1Ep6WzLQXL/cajoRweO3zE3+Q olVg== X-Gm-Message-State: APjAAAW3AZMdqb9jW5iGfkaAu0dsvFsMrJhcxiRzsdEY5BjhmSEnxxsF vY2Q6OomPetkhL4O+w6m/9gLpQx4 X-Google-Smtp-Source: APXvYqzMv28R49oB/yq7tkr8/h9jk31nWU5YgGQZwFioAHicOaUxddZJqBcBFZu6smG+O3u/bEUAtg== X-Received: by 2002:a7b:cbc9:: with SMTP id n9mr15376266wmi.89.1578840457515; Sun, 12 Jan 2020 06:47:37 -0800 (PST) Received: from pali ([2a02:2b88:2:1::5cc6:2f]) by smtp.gmail.com with ESMTPSA id i10sm11045750wru.16.2020.01.12.06.47.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 Jan 2020 06:47:36 -0800 (PST) Date: Sun, 12 Jan 2020 15:47:35 +0100 From: Pali =?utf-8?B?Um9ow6Fy?= To: linux-fsdevel@vger.kernel.org, Jan Kara , "Steven J. Magnani" Subject: udf: Commit b085fbe2ef7fa (udf: Fix crash during mount) broke CD-RW support Message-ID: <20200112144735.hj2emsoy4uwsouxz@pali> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="covvha46va3s45fn" Content-Disposition: inline User-Agent: NeoMutt/20180716 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org --covvha46va3s45fn Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello! Commit b085fbe2ef7fa (udf: Fix crash during mount) introduced check that UDF disk with PD_ACCESS_TYPE_REWRITABLE access type would not be able to mount in R/W mode. This commit was added in Linux 4.20. But most tools which generate UDF filesystem for CD-RW set access type to rewritable, so above change basically disallow usage of CD-RW discs formatted to UDF in R/W mode. Linux's cdrwtool and mkudffs (in all released versions), Windows Nero 6, NetBSD's newfs_udf -- all these tools uses rewritable access type for CD-RW media. In UDF 1.50, 2.00 and 2.01 specification there is no information which UDF access type should be used for CD-RW medias. In UDF 2.60, section 2.2.14.2 is written: A partition with Access Type 3 (rewritable) shall define a Freed Space Bitmap or a Freed Space Table, see 2.3.3. All other partitions shall not define a Freed Space Bitmap or a Freed Space Table. Rewritable partitions are used on media that require some form of preprocessing before re-writing data (for example legacy MO). Such partitions shall use Access Type 3. Overwritable partitions are used on media that do not require preprocessing before overwriting data (for example: CD-RW, DVD-RW, DVD+RW, DVD-RAM, BD-RE, HD DVD-Rewritable). Such partitions shall use Access Type 4. And in 6.14.1 (Properties of CD-MRW and DVD+MRW media and drives) is: The Media Type is Overwritable (partition Access Type 4, overwritable) Similar info is in UDF 2.50. So I think that UDF 2.60 is clear that for CD-RW medias (formatted in normal or MRW mode) should be used Overwritable access type. But all mentioned tools were probably written prior to existence of UDF 2.60 specifications, probably targeting only UDF 1.50 versions at that time. I checked that they use Unallocated Space Bitmap (and not Freed Space Bitmap), so writing to these filesystems should not be a problem. How to handle this situation? UDF 2.01 nor 1.50 does not say anything for access type on CD-RW and there are already tools which generates UDF 1.50 images which does not matches UDF 2.60 requirements. I think that the best would be to relax restrictions added in commit b085fbe2ef7fa to allow mounting mounting udf fs with rewritable access type in R/W mode if Freed Space Bitmap/Table is not used. I'm really not sure if existing udf implementations take CD-RW media with overwritable media type. E.g. prehistoric wrudf tool refuse to work with optical discs which have overwritable access type. I supports only UDF 1.50. --=20 Pali Roh=C3=A1r pali.rohar@gmail.com --covvha46va3s45fn Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EARECAB0WIQS4VrIQdKium2krgIWL8Mk9A+RDUgUCXhsxhQAKCRCL8Mk9A+RD UnPYAJ9e/KG9iPWabYYAZMoCqVxNYckvSgCfUdVUibSu2AZ6+iKMLBNz1lQxpQI= =NYtz -----END PGP SIGNATURE----- --covvha46va3s45fn--