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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 902D9C433E0 for ; Mon, 15 Mar 2021 23:08:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 598F464F01 for ; Mon, 15 Mar 2021 23:08:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229838AbhCOXHq (ORCPT ); Mon, 15 Mar 2021 19:07:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:47510 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230325AbhCOXH0 (ORCPT ); Mon, 15 Mar 2021 19:07:26 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 224A964F01; Mon, 15 Mar 2021 23:07:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615849646; bh=216nMEowzSSSHh5Fh7E+RUDl9qhqxuC/Rz+ZbSY9WYc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KaaGFfEykq3eS1IbHdscDAGxAysgM/veoE4wDshY7kSpz8XKNPGciXKTC081PQ/U6 73cPY07Mst0hw1Irq6qFvv2b3MaU81vIY0D/jSwjr6sbY15Yzf/bhzKcIGHz5KgyaR ICawpolfbfMSqsiBGbUddtKrlHG7BwLAf+o3X+hNxBlEyS7Lzrf6SVrgSLOdh/R4Ty cqMFe8Dw+luLnEIbtr7aoOTtdjdgrFHwkwv0wGmjcjrgMjLq8de7JbKjI/U8hr7MtI PYhoT08eGnuBbBLRpJNPANLJUVHPDAGGv9lZaOE4xArcioNq56GV4q69r28aTmJ8Hx mFceRlPKksF/A== Date: Mon, 15 Mar 2021 16:07:24 -0700 From: Eric Biggers To: Boris Burkov Cc: linux-btrfs@vger.kernel.org, kernel-team@fb.com, linux-fscrypt@vger.kernel.org Subject: Re: [PATCH v2 1/5] btrfs: add compat_flags to btrfs_inode_item Message-ID: References: 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-fscrypt@vger.kernel.org On Fri, Mar 05, 2021 at 11:26:29AM -0800, Boris Burkov wrote: > The tree checker currently rejects unrecognized flags when it reads > btrfs_inode_item. Practically, this means that adding a new flag makes > the change backwards incompatible if the flag is ever set on a file. > > Take up one of the 4 reserved u64 fields in the btrfs_inode_item as a > new "compat_flags". These flags are zero on inode creation in btrfs and > mkfs and are ignored by an older kernel, so it should be safe to use > them in this way. > > Signed-off-by: Boris Burkov How does this interact with the RO_COMPAT filesystem flag which is also being added? - Eric