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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 A86DEC433DF for ; Thu, 8 Oct 2020 19:12:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51EC82184D for ; Thu, 8 Oct 2020 19:12:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729572AbgJHTMl (ORCPT ); Thu, 8 Oct 2020 15:12:41 -0400 Received: from relay11.mail.gandi.net ([217.70.178.231]:43797 "EHLO relay11.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725887AbgJHTMk (ORCPT ); Thu, 8 Oct 2020 15:12:40 -0400 Received: from localhost (unknown [67.5.25.97]) (Authenticated sender: josh@joshtriplett.org) by relay11.mail.gandi.net (Postfix) with ESMTPSA id 4603110000B; Thu, 8 Oct 2020 19:12:34 +0000 (UTC) Date: Thu, 8 Oct 2020 12:12:31 -0700 From: Josh Triplett To: Andreas Dilger Cc: "Theodore Y. Ts'o" , "Darrick J. Wong" , Jan Kara , Linux Kernel Mailing List , Ext4 Developers List Subject: Re: ext4 regression in v5.9-rc2 from e7bfb5c9bb3d on ro fs with overlapped bitmaps Message-ID: <20201008191231.GA44285@localhost> References: <20201005173639.GA2311765@magnolia> <20201006003216.GB6553@localhost> <20201006025110.GJ49559@magnolia> <20201006031834.GA5797@mit.edu> <20201006050306.GA8098@localhost> <20201006133533.GC5797@mit.edu> <20201007080304.GB1112@localhost> <20201007143211.GA235506@mit.edu> <20201007201424.GB15049@localhost> 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, Oct 07, 2020 at 08:57:12PM -0600, Andreas Dilger wrote: > On Oct 7, 2020, at 2:14 PM, Josh Triplett wrote: > > If those aren't the right way to express that, I could potentially > > adapt. I had a similar such conversation on linux-ext4 already (about > > inline data with 128-bit inodes), which led to me choosing to abandon > > 128-byte inodes rather than try to get ext4 to support what I wanted > > with them, because I didn't want to be disruptive to ext4 for a niche > > use case. In the particular case that motivated this thread, what I was > > doing already worked in previous kernels, and it seemed reasonable to > > ask for it to continue to work in new kernels, while preserving the > > newly added checks in the new kernels. > > This was discussed in the "Inline data with 128-byte inodes?" thread > back in May. While Jan was not necessarily in favour of this, I was > actually OK with improving the ext4 code to handle this case better, > since it would (at minimum) clean up ext4 to make a clear separation > of how it is detecting data in the i_block[] array and the system.data > xattr, and I don't think it added any complexity to the code. > > I even posted a WIP patch to that effect, but didn't get a response back: > https://marc.info/?l=linux-ext4&m=158863275019187 My apologies, I thought I responded to that. It looks promising to me, though I wouldn't have the bandwidth to take it to completion anytime soon. > I *do* think that inline_data is an under-appreciated feature that I > would be happy to see some improvements with. I don't think that small > files are a niche use case, and if we can clean up the inline_data code > to work with 128-byte inodes I'm not against that, even though I'm not > going to use that combination of features myself. I'd love to see that happen. At the time, it seemed like too large of a change to block on, which is why I ended up deciding to switch to 256-byte inodes.