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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 AF815C3F2D1 for ; Thu, 5 Mar 2020 20:57:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 85D9D20801 for ; Thu, 5 Mar 2020 20:57:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726087AbgCEU53 (ORCPT ); Thu, 5 Mar 2020 15:57:29 -0500 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:52278 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726049AbgCEU53 (ORCPT ); Thu, 5 Mar 2020 15:57:29 -0500 Received: from callcc.thunk.org (guestnat-104-133-0-105.corp.google.com [104.133.0.105] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 025KvP3n009056 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 5 Mar 2020 15:57:25 -0500 Received: by callcc.thunk.org (Postfix, from userid 15806) id 90F0842045B; Thu, 5 Mar 2020 15:57:24 -0500 (EST) Date: Thu, 5 Mar 2020 15:57:24 -0500 From: "Theodore Y. Ts'o" To: Eric Whitney Cc: linux-ext4@vger.kernel.org Subject: Re: [PATCH] ext4: remove EXT4_EOFBLOCKS_FL and associated code Message-ID: <20200305205724.GE20967@mit.edu> References: <20200211210216.24960-1-enwlinux@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200211210216.24960-1-enwlinux@gmail.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue, Feb 11, 2020 at 04:02:16PM -0500, Eric Whitney wrote: > The EXT4_EOFBLOCKS_FL inode flag is used to indicate whether a file > contains unwritten blocks past i_size. It's set when ext4_fallocate > is called with the KEEP_SIZE flag to extend a file with an unwritten > extent. However, this flag hasn't been useful functionally since > March, 2012, when a decision was made to remove it from ext4. > > All traces of EXT4_EOFBLOCKS_FL were removed from e2fsprogs version > 1.42.2 by commit 010dc7b90d97 ("e2fsck: remove EXT4_EOFBLOCKS_FL flag > handling") at that time. Now that enough time has passed to make > e2fsprogs versions containing this modification common, this patch now > removes the code associated with EXT4_EOFBLOCKS_FL from the kernel as > well. > > This change has two implications. First, because pre-1.42.2 e2fsck > versions only look for a problem if EXT4_EOFBLOCKS_FL is set, and > because that bit will never be set by newer kernels containing this > patch, old versions of e2fsck won't have a compatibility problem with > files created by newer kernels. > > Second, newer kernels will not clear EXT4_EOFBLOCKS_FL inode flag bits > belonging to a file written by an older kernel. If set, it will remain > in that state until the file is deleted. Because e2fsck versions since > 1.42.2 don't check the flag at all, no adverse effect is expected. > However, pre-1.42.2 e2fsck versions that do check the flag may report > that it is set when it ought not to be after a file has been truncated > or had its unwritten blocks written. In this case, the old version of > e2fsck will offer to clear the flag. No adverse effect would then > occur whether the user chooses to clear the flag or not. > > Signed-off-by: Eric Whitney Applied, thanks. - Ted