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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,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 74E4DC433DB for ; Wed, 10 Feb 2021 01:37:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3E45A64E3F for ; Wed, 10 Feb 2021 01:37:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233311AbhBJBgi (ORCPT ); Tue, 9 Feb 2021 20:36:38 -0500 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:56941 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S234907AbhBIXXu (ORCPT ); Tue, 9 Feb 2021 18:23:50 -0500 Received: from cwcc.thunk.org (pool-72-74-133-215.bstnma.fios.verizon.net [72.74.133.215]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 119NMoVa000363 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 9 Feb 2021 18:22:51 -0500 Received: by cwcc.thunk.org (Postfix, from userid 15806) id C995F15C39E3; Tue, 9 Feb 2021 18:22:50 -0500 (EST) Date: Tue, 9 Feb 2021 18:22:50 -0500 From: "Theodore Ts'o" To: Andreas Dilger Cc: Daniel Rosenberg , Eric Biggers , Andreas Dilger , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Gabriel Krisman Bertazi , kernel-team@android.com, Paul Lawrence Subject: Re: [PATCH 1/2] ext4: Handle casefolding with encryption Message-ID: References: <20210203090745.4103054-2-drosen@google.com> <56BC7E2D-A303-45AE-93B6-D8921189F604@dilger.ca> 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-kernel@vger.kernel.org On Wed, Feb 03, 2021 at 11:31:28AM -0500, Theodore Ts'o wrote: > On Wed, Feb 03, 2021 at 03:55:06AM -0700, Andreas Dilger wrote: > > > > It looks like this change will break the dirdata feature, which is similarly > > storing a data field beyond the end of the dirent. However, that feature also > > provides for flags stored in the high bits of the type field to indicate > > which of the fields are in use there. > > The first byte of each field stores > > the length, so it can be skipped even if the content is not understood. > > Daniel, for context, the dirdata field is an out-of-tree feature which > is used by Lustre, and so has fairly large deployed base. So if there > is a way that we can accomodate not breaking dirdata, that would be > good. > > Did the ext4 casefold+encryption implementation escape out to any > Android handsets? So from an OOB chat with Daniel, it appears that the ext4 casefold+encryption implementation did in fact escape out to Android handsets. So I think what we will need to do, ultiumately, is support one way of supporting the casefold IV in the case where "encryption && casefold", and another way when "encryption && casefold && dirdata". That's going to be a bit sucky, but I don't think it should be that complex. Daniel, Andreas, does that make sense to you? - Ted