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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 C9F34C433E0 for ; Thu, 4 Mar 2021 00:51:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96D3D64EBB for ; Thu, 4 Mar 2021 00:51:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238123AbhCDAum (ORCPT ); Wed, 3 Mar 2021 19:50:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:36710 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242640AbhCCRPO (ORCPT ); Wed, 3 Mar 2021 12:15:14 -0500 Received: by mail.kernel.org (Postfix) with ESMTPS id BE5F064E28 for ; Wed, 3 Mar 2021 17:14:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614791667; bh=oqfPZUEOaBSmYJzlz6we6WgVrCCaSSkoksEAmDDTxFo=; h=From:To:Subject:Date:In-Reply-To:References:From; b=agnQuo64UfHCpDXK78Co7rA+oLxKHMKYAuraC7w+LZxxaZaO5D2g8h5ZYpTJNpGzR 5fT0eaVRP+8J6ORL4cq5mfuxTCbhomz6q1u6kb9W0XFOjWwSzYIuxCHxvHs5tBvHYy wtpvE3SjxI5Q5IluW/n8cbTqQnIMAYmOpqUz7UloR0uVlDJh4bJ3w8fsBkgPBC7m0j 3FNwssfI9vgCtYhnXrJzXRA1zxyrS8ZNQZgpbqNAqshYiJAaWcS6SMRtuQW25OO3kI P2cs7sXrKnKGAb2/e5x+sYm8eJ41XPyHtz1nnms4RTSbZp4hrz5LZ4h8Kz1iLNjJgS KDsNTn4A25Lxw== From: bugzilla-daemon@bugzilla.kernel.org To: linux-ext4@vger.kernel.org Subject: [Bug 211971] Incorrect fix by e2fsck for blocks_count corruption Date: Wed, 03 Mar 2021 17:14:27 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo fs_ext4@kernel-bugs.osdl.org X-Bugzilla-Product: File System X-Bugzilla-Component: ext4 X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: tmahmud@iastate.edu X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: fs_ext4@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=3D211971 --- Comment #3 from tmahmud@iastate.edu --- Hello Ted, Thank you very much for the detailed clarification! It mostly makes sense to me. But I still have two questions regarding the debugfs/e2fsck behavior. (1) > > > debugfs -w image > > > debugfs: ssv blocks_count 4000 > > > debugfs: q >=20 > This will update the blocks_count in the primary and all secondary > backups.=20=20 This is different from what I observed. In my experiment, =E2=80=9Cdebugfs:= ssv blocks_count 4000=E2=80=9D only updated the blocks_count (and the checksum)= in the primary superblock. All secondary backups were not updated (neither the blocks_count nor the checksum). Does this imply that there is a potential b= ug in debugfs (because it didn=E2=80=99t update all backups as you suggested)?= I=E2=80=99m attaching two images before and after =E2=80=9Cdebugfs: ssv blocks_count 40= 00=E2=80=9D for reference (=E2=80=9Cimage1_before=E2=80=9D, =E2=80=9Cimage1_after=E2=80=9D)= . I have verified backups are not updated by dumping the backup superblocks information with dumpe2fs. (2) > The problem is that e2fsck can't really determine that the blocks > count field has been corrupted.=20=20 In my experiment, I observed that e2fsck was able to fix the debugfs-modifi= ed primary superblock using secondary superblocks when the secondary superbloc= ks are located in default locations (ex. 8193rd block). However, in an image w= here secondary superblocks are not in their default locations (ex:513rd block), I found that e2fsck cannot fix the primary superblock using secondary superblocks. So e2fsck=E2=80=99s behavior is inconsistent depending on the = location of the secondary superblocks. Could you please comment on this? --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=