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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 582EDC04AAC for ; Mon, 20 May 2019 12:53:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2DEE420645 for ; Mon, 20 May 2019 12:53:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558356805; bh=06HwVM8mU9mLIabTQ9BoZcRofJbXFiysdQVqdvYyGC0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=J8ispgM6GP2Xe09Sz0G9Hc6wV8htgxkR730sFi0kTyw8sASoyjNeVMS16ytuuz2T0 md9LSlDd+JdkFVGluc21YuyE4v6J8wGgCYPosq4hhtjtjiZ8zz34o6AGSXudVul/Y4 3cDTlLhQtwUs7zSlU1f7vGhCuNbUhaJ8+gryJ7pI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732342AbfETMRo (ORCPT ); Mon, 20 May 2019 08:17:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:58816 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731033AbfETMRo (ORCPT ); Mon, 20 May 2019 08:17:44 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 21F1A20863; Mon, 20 May 2019 12:17:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558354663; bh=06HwVM8mU9mLIabTQ9BoZcRofJbXFiysdQVqdvYyGC0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LpupQ+BQcLsR/LXrgsOSBmDciQmFVlXr9uE4PFIw3iJWcV16czPpkRHzUjqPImgvG UI691M/+Pn1z2kP1afbWyTiM8qMv2kuGcT/M2r2rqr6iEaeouAGCr4GRI42HxS8/4x eIKtA5stMu7j8U7GIwUMfZSjI6Qa2urvFGcQTY8M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lukas Czerner , Theodore Tso , stable@kernel.org Subject: [PATCH 4.9 42/44] ext4: fix data corruption caused by overlapping unaligned and aligned IO Date: Mon, 20 May 2019 14:14:31 +0200 Message-Id: <20190520115235.856197660@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190520115230.720347034@linuxfoundation.org> References: <20190520115230.720347034@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Lukas Czerner commit 57a0da28ced8707cb9f79f071a016b9d005caf5a upstream. Unaligned AIO must be serialized because the zeroing of partial blocks of unaligned AIO can result in data corruption in case it's overlapping another in flight IO. Currently we wait for all unwritten extents before we submit unaligned AIO which protects data in case of unaligned AIO is following overlapping IO. However if a unaligned AIO is followed by overlapping aligned AIO we can still end up corrupting data. To fix this, we must make sure that the unaligned AIO is the only IO in flight by waiting for unwritten extents conversion not just before the IO submission, but right after it as well. This problem can be reproduced by xfstest generic/538 Signed-off-by: Lukas Czerner Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/file.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -163,6 +163,13 @@ ext4_file_write_iter(struct kiocb *iocb, } ret = __generic_file_write_iter(iocb, from); + /* + * Unaligned direct AIO must be the only IO in flight. Otherwise + * overlapping aligned IO after unaligned might result in data + * corruption. + */ + if (ret == -EIOCBQUEUED && unaligned_aio) + ext4_unwritten_wait(inode); inode_unlock(inode); if (ret > 0)