From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail01.ukr.de (mail01.ukr.de [193.175.194.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 815091A28C for ; Tue, 19 Nov 2024 08:16:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.175.194.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732004205; cv=none; b=iGDk0Gi8IeP7Udr8CG4xjtIfkIYtcDcRYNIqSTO7TYhPQxRxZAdOUDdOrkRCuxlipYxnkXb+J0a+ZjJg4iwbW1sKF33jiPO/HRp59EOfXm1CoveOnroqCetsz7AnxnUlwkimaPw/pC5/1KsOY3zInxfl7f1veea6EGIZVoJd95U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732004205; c=relaxed/simple; bh=TP+qTHi+xLaKd69vs7SxOzlVqUtM1BQiv5cz2H+IZiY=; h=From:To:CC:Subject:Date:Message-ID:References:In-Reply-To: Content-Type:MIME-Version; b=aUU78G8QAZL6myO3gJzM1KuPAlDauoK5Xeh/ys4dVLrT5a8Y3Jvqoog5kq36X+Z+zKcn0+O9L+bCM7m1cJE0PVlyz2gwytFyOURmNvSWlEJJkmk6RvSwSwQ4BdP/Q3YzVrHMmoWoAjoIF3gszWcA6R1xfBOqY7KmxNUgrsJvkpI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ukr.de; spf=pass smtp.mailfrom=ukr.de; arc=none smtp.client-ip=193.175.194.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ukr.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ukr.de X-CSE-ConnectionGUID: fZw1HZgKTEGNhRlnGgd48w== X-CSE-MsgGUID: gq/1lAU5QxyKeGBoC09unw== X-ThreatScanner-Verdict: Negative X-IronPort-AV: E=McAfee;i="6700,10204,11260"; a="1178057" X-IronPort-AV: E=Sophos;i="6.12,165,1728943200"; d="scan'208";a="1178057" Received: from unknown (HELO ukr-excmb03.ukr.local) ([172.24.6.63]) by dmz-infcsg01.ukr.dmz with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Nov 2024 09:15:29 +0100 Received: from ukr-excmb03.ukr.local (172.24.6.63) by ukr-excmb03.ukr.local (172.24.6.63) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Tue, 19 Nov 2024 09:15:29 +0100 Received: from ukr-excmb03.ukr.local ([fe80::1cb4:6e0c:6da4:a8a0]) by ukr-excmb03.ukr.local ([fe80::1cb4:6e0c:6da4:a8a0%4]) with mapi id 15.01.2507.039; Tue, 19 Nov 2024 09:15:29 +0100 From: "Windl, Ulrich" To: Krister Johansen , "util-linux@vger.kernel.org" CC: Karel Zak , "systemd-devel@lists.freedesktop.org" , David Reaver , Theodore Ts'o Subject: RE: [EXT] [systemd-devel] [PATCH] libblkid: fix spurious ext superblock checksum mismatches Thread-Topic: [EXT] [systemd-devel] [PATCH] libblkid: fix spurious ext superblock checksum mismatches Thread-Index: AQHbOf62N1rTufxXrkOKiFKYcnEHp7K+QXPA Date: Tue, 19 Nov 2024 08:15:29 +0000 Message-ID: <7bc43689ca4249f18c60fa4b063822ea@ukr.de> References: <6d16e6d83ab48d2ea4402db17c9c0ed5514933a7.1731961869.git.kjlx@templeofstupid.com> In-Reply-To: <6d16e6d83ab48d2ea4402db17c9c0ed5514933a7.1731961869.git.kjlx@templeofstupid.com> Accept-Language: de-DE, en-US Content-Language: de-DE X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: util-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 > -----Original Message----- > From: systemd-devel On > Behalf Of Krister Johansen > Sent: Monday, November 18, 2024 9:35 PM > To: util-linux@vger.kernel.org > Cc: Karel Zak ; systemd-devel@lists.freedesktop.org; > David Reaver ; Theodore Ts'o > Subject: [EXT] [systemd-devel] [PATCH] libblkid: fix spurious ext superbl= ock > checksum mismatches >=20 > Reads of ext superblocks can race with updates. If libblkid observes a [Windl, Ulrich]=20 I really wonder: Can one single block be inconsistent when read, considering that the block = on disk is not inconsistent? That would mean that the block buffer you are reading is being modified by = another process. AFAIK the basic UNIX semantic guarantee that a block is read atomically; if= it's not, something is severely broken, and I don't think that O_DIRECT fi= xes that.