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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 6D953C4320A for ; Tue, 17 Aug 2021 18:57:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 505C760FD9 for ; Tue, 17 Aug 2021 18:57:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230373AbhHQS6V (ORCPT ); Tue, 17 Aug 2021 14:58:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:40454 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230040AbhHQS6V (ORCPT ); Tue, 17 Aug 2021 14:58:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6D6EE60F58; Tue, 17 Aug 2021 18:57:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629226667; bh=2XcXNJckxVKqAUkQr3OnLHOMlEXeXg+rMqgZHIzsIwQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZM19eiaP830Jjnq7WpgBd757cueDeUTKGXydS3fRcMzp35BHWeA1kbaTfHQntpUKg aBJBvPvUYSoLD7drxmoiyEqyQAUlakf/ToVSnsJLrO+XBdkzVmBZQdCEZYYZK/2dpl ITkP1rQYvN+ddd5YSddzCS4hHinnnovMXQGVQe9/C+VPzsdbYBFfrXixrd+qkGA/wS hQ4yxQTfmnpI9MO6e1AmDv7dwk34YBa1uxj3S3I+WmUWHOgWA6sjb1mhPGK4Mgj7or Vf6M2m1tkPuW5Jgsy4ClIceTF4N6Xjq+Qvqt1fSUnEWqEM7Kac8PNg3IgLHQvTl/GU hOjJWx0rbekdA== Date: Tue, 17 Aug 2021 11:57:46 -0700 From: Jaegeuk Kim To: Christoph Hellwig Cc: Eric Biggers , Chao Yu , Theodore Ts'o , linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] f2fs: remove broken support for allocating DIO writes Message-ID: References: <20210728015154.171507-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 08/17, Christoph Hellwig wrote: > On Mon, Aug 16, 2021 at 07:03:21PM -0700, Eric Biggers wrote: > > Freeing preallocated blocks on error would be better than nothing, although note > > that the preallocated blocks may have filled an arbitrary sequence of holes -- > > so simply truncating past EOF would *not* be sufficient. > > > > But really filesystems need to be designed to never expose uninitialized data, > > even if I/O errors or a sudden power failure occurs. It is unfortunate that > > f2fs apparently wasn't designed with that goal in mind. > > > > In any case, I don't think we can proceed with any other f2fs direct I/O > > improvements until this data leakage bug can be solved one way or another. If > > my patch to remove support for allocating writes isn't acceptable and the > > desired solution is going to require some more invasive f2fs surgery, are you or > > Chao going to work on it? I'm not sure there's much I can do here. > > Btw, this is generally a problem for buffered I/O as well, although the > window for exposing uninitialized blocks on a crash tends to be smaller. How about adding a warning message when we meet an error with preallocated unwritten blocks? In the meantime, can we get the Eric's patches for iomap support? I feel that we only need to modify the preallocation and error handling parts?