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=-0.5 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 2917BC677F5 for ; Sun, 7 Oct 2018 10:51:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9E422087D for ; Sun, 7 Oct 2018 10:51:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C9E422087D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gmx.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-btrfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726367AbeJGR6H (ORCPT ); Sun, 7 Oct 2018 13:58:07 -0400 Received: from mout.gmx.net ([212.227.15.18]:60847 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726264AbeJGR6H (ORCPT ); Sun, 7 Oct 2018 13:58:07 -0400 Received: from [0.0.0.0] ([210.140.77.29]) by mail.gmx.com (mrgmx003 [212.227.17.184]) with ESMTPSA (Nemesis) id 0M7YF5-1foI6i3PEd-00xKCP; Sun, 07 Oct 2018 12:51:12 +0200 Received: from [0.0.0.0] ([210.140.77.29]) by mail.gmx.com (mrgmx003 [212.227.17.184]) with ESMTPSA (Nemesis) id 0M7YF5-1foI6i3PEd-00xKCP; Sun, 07 Oct 2018 12:51:12 +0200 Subject: Re: Two partitionless BTRFS drives no longer seen as containing BTRFS filesystem To: evan d Cc: linux-btrfs@vger.kernel.org References: <54132790-3f56-ef0f-d818-4f62f0b0a608@gmx.com> <64cd61fe-5e78-6201-f4b2-e88efba139bc@gmx.com> <2122b08c-0fa9-b774-cbad-67b71f5084d4@gmx.com> <14c82713-72c8-a243-293b-5c482031f70a@gmx.com> <7ffc25c7-1442-99da-8600-add6b3ce2dd4@gmx.com> From: Qu Wenruo Openpgp: preference=signencrypt Autocrypt: addr=quwenruo.btrfs@gmx.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="H5x3yGwpBkY2bGsiMw2FO9i6qMDcxfghd" X-Provags-ID: V03:K1:5AfmDd5ZVSWVI4WrQ1fRXkJLVrkkreAgPMcM3PTbhFEKCiZXw+m lKOKdpCfGrMo9hgFQa/LK45wxcQ/8+yizThlaME6rpm94QbpMMuOmDVWpNUTyW3EofZdkOS Yr0YV+/HLlHd+ZsOKpc9cttE+wmhX9uhxpzZKDHCAzN4Zc6/m3STZ2YB7xfdEOIDDJENQN2 VmYEeFd2NhUFmwhyPQVfw== X-UI-Out-Filterresults: notjunk:1;V01:K0:rovAAS8Mln4=:2wFAvam+FRyEID2qhWE11b IAxFL0BDJ0XFvorl2yHaZ0Hf/YWhRUbIrVG9wap5cvyiRvyZpEEpc1OZVUAc0Wg3lDZtWZRvt I7JG5/tqChT41aS7DEsmEXPKWXW8s0es20jV3bHaT5UWIKJvXLEyjDg3Wl5RLRse8v4bHX27b Rzdtnoc5c6Y0IMZnmNcKvzwWGpxT6kFQJDEJ3nt1NSsCgkeMoO9oXctNPFFRmE7b20ul5DyoD wmSrK17Onp7bCluzQZpaviYbRMTjAuA6VQteuXxRdbSJVznOvKFOH31DsehezMeGpSJpNsV+J sTGfj3KQFi2k42NL0U6WzpzUlSN/B/G/sL2U4AfPrkpNwP5HWwy0WloM53RtErlm6JGBJaMTV qFQ/EunzQl3gnUZ35DTyHWuk/8TkM0TBS8jtR3934NvCa7sDMDYg70qzL2o/uC0MdedUPh8zO MVwGSPgIjESB6g+Y95QBIgkO39YvyYHBR2r/qHzewSfb5wdsEmdWKLwaRf773hEcefc+D60aK Rmr0TRVvyTZPgSMP+fV0M8P5Yy0a8YENIJ3cLXHUQflJNTzgmowV8QMGZAfhdWgSIrysLgaRT AkrZj+FcYrzfDerW5tlfMSMqwWMezOd1g4tYumbr/tsQCaO0/wfqPOowfYVCcqye8XtpVV9jb SqXkJmxZIl6WZ9D/svWWRbyElBgNMK13oF0FjokU/6y1ftQxE/j70VZqlmchR0zZalSTSm8FQ T02lfUqpWCuTwGkURjFJ/uB81cGVjI2q/XWCH0rYk8TlhOHIqYn54BZPQyDkYIqLMy8X/g8Ta BTcbUnpOnE2KCPEBGF3fFfp6w7pTA== Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --H5x3yGwpBkY2bGsiMw2FO9i6qMDcxfghd Content-Type: multipart/mixed; boundary="h6xU4VMnzgoS3Z6myjU9zQmo9sudUSSHu"; protected-headers="v1" From: Qu Wenruo To: evan d Cc: linux-btrfs@vger.kernel.org Message-ID: <8968c012-7732-2338-c505-2027539cbe56@gmx.com> Subject: Re: Two partitionless BTRFS drives no longer seen as containing BTRFS filesystem References: <54132790-3f56-ef0f-d818-4f62f0b0a608@gmx.com> <64cd61fe-5e78-6201-f4b2-e88efba139bc@gmx.com> <2122b08c-0fa9-b774-cbad-67b71f5084d4@gmx.com> <14c82713-72c8-a243-293b-5c482031f70a@gmx.com> <7ffc25c7-1442-99da-8600-add6b3ce2dd4@gmx.com> In-Reply-To: --h6xU4VMnzgoS3Z6myjU9zQmo9sudUSSHu Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2018/10/7 =E4=B8=8B=E5=8D=886:39, evan d wrote: >>> like so?: >>> grep -obUaP "\x5F\x42\x48\x52\x66\x53\x5F\x4D" /dev/sdc >>> >> Yes. And it will be very slow, since you're going to read out the whol= e >> disk. >> >> But I don't really think you would get some hit, according to current >> result. >=20 > Ok, so it is what it is. Based on what you're telling me, whilst the > data may be there and intact, the superblock is irretrievably damaged > and the data is thus for all intents and purposes lost. Although the result is the same (data all lost), but I don't believe it's only super block corrupted. If you have some special magic string, like "#!/bin/bash" or "\x7f\x45 \x4c\x46\x02\x01\x01\x00" (elf header) , you could try to grep through the whole disk. I believe the data (or at least part of the data) is also corrupted in this case. >=20 > I may as well use wipefs to clear crud from both drives, partition and > format them and then use them elsewhere. -- this more or less > accurately summarise the situation? Unfortunately, yes. Thanks, Qu >=20 --h6xU4VMnzgoS3Z6myjU9zQmo9sudUSSHu-- --H5x3yGwpBkY2bGsiMw2FO9i6qMDcxfghd Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAlu55RsACgkQwj2R86El /qgo9wf/epbzoyhIU7/YrZjVH3ozoekrYxe9yc32079mRWheZkiAKkUToRJOwuR3 0RZ+2wfnKWHHnzRzohBXEfAkJlXxukI+KhXxbnLkds5ejqSwMym7+4mKmht3zGqg nhos8JM8aHQajOZz8KoFkSowrLELfrCooHQO83loXfdtKEZRASRyLz1NiFh+KLjK sVxygZrz18exo0F5TLTFqdCE8h6tZ8O1AaRFZ4dfH0CECpqrBwbvfDpHTV98Ue6t xC8vEaertlmtQZrRZzHzqGa8A7PNLnySmw1jiIM5l7EQXf9WmjTzSMPhgOO83rbE HKNgGG2Jieh4xsm1dzJyVMHZddp0Jw== =39jv -----END PGP SIGNATURE----- --H5x3yGwpBkY2bGsiMw2FO9i6qMDcxfghd--