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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76BC2C19F2A for ; Thu, 11 Aug 2022 21:09:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236603AbiHKVJ3 (ORCPT ); Thu, 11 Aug 2022 17:09:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43460 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236178AbiHKVJM (ORCPT ); Thu, 11 Aug 2022 17:09:12 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B43F4A0336; Thu, 11 Aug 2022 14:08:16 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3A8DBB82076; Thu, 11 Aug 2022 21:08:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 445ECC433C1; Thu, 11 Aug 2022 21:08:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660252093; bh=5YoNnclwkL9ZEKqBXwozTmi5USJU6wLeQwMyu0umXvo=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=fAq5dnZCibGNARbJ3p4vwxnL2etCHVCUMFa/xsoQS2oGBF46i1cCpzxhoGIOTQ0Y6 RtV+oG/vMCGCl6kqX1qJO5EwDYdZGdEoH8C4YSYp2KbT9r2XPbjAa/1AvZJPFFgabZ t5eOeNe1k5eRpiH0QLiiwaHkdtZGPL+Oi4w2VdoeOSJdC6lTJuvxBpOCJS2nyN3s+f strqRaiwYymSEi+ovJOmbJsSFccl6TvojVBgJlgSUdB0VRX0YCIEFiY9kw+lOe82ny inecNUU3mIXdSRtQYy0SfPaQNEU5FYB1pTn7mK8M/J6Z1C4RK3qzMh55i6iHS2fNQ1 +mtvB7kp/utyA== Message-ID: <5d0b0367a5e28ec5b1f3b995c7792ff9a5cbcbd4.camel@kernel.org> Subject: Re: [GIT PULL] Ceph updates for 5.20-rc1 From: Jeff Layton To: Ilya Dryomov , Linus Torvalds Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, Al Viro , Matthew Wilcox Date: Thu, 11 Aug 2022 17:08:11 -0400 In-Reply-To: References: <20220811152446.281723-1-idryomov@gmail.com> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4 (3.44.4-1.fc36) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org On Thu, 2022-08-11 at 22:55 +0200, Ilya Dryomov wrote: > On Thu, Aug 11, 2022 at 10:04 PM Linus Torvalds > wrote: > >=20 > > On Thu, Aug 11, 2022 at 8:25 AM Ilya Dryomov wrote= : > > >=20 > > > [..] Several patches > > > touch files outside of our normal purview to set the stage for bringi= ng > > > in Jeff's long awaited ceph+fscrypt series in the near future. All o= f > > > them have appropriate acks and sat in linux-next for a while. > >=20 > > What? No. > >=20 > > I'm looking at the fs/dcache.c change, for example, and don't see the > > relevant maintainers having acked it at all. > >=20 > > The mmdebug.h file similarly seems to not have the actual maintainer > > acks, and seems just plain stupid (why does it add that new folio > > warning macro, when the existing folio warning macro > > VM_WARN_ON_ONCE_FOLIO() is *better*? > >=20 > > Those are some very core files, and while the changes seem harmless, > > they sure don't seem obviously ok. > >=20 > > What's the point of warning about bogus folios more than once? That's > > a debug warning - if it hits even once, that's already "uhhuh, > > something is bad". Showing the warning more than once is likely just > > going to cause more problems, not give you more information. >=20 > Xiubo and Jeff used it to track down some issues between netfs library > and folio code that have been randomly plaguing our automated tests for > a couple of releases. We already knew that there were issues in that > area and the actual occurrences mattered. This was done in cooperation > with Willy and, since he was involved and this is a no-impact change, > I didn't think twice. >=20 > >=20 > > And did somebody verify that d_same_name() is still inlined in the > > place that truly *matters*? Because from my quick test, that patch > > broke it. Now __d_lookup() does a function call. > >=20 > > And I _suspect_ it's all ok, because it turns out that > > __d_lookup_rcu() is the *really* hot case, and that one has inlined it > > all manually. > >=20 > > But this kind of "we touch some *truly* core functionality, without > > the acks from the maintainers, and then we *claim* to have relevant > > acks" is really not even remotely ok. >=20 > I raised the lack of a formal Acked-by from Al on the dcache change > with Jeff a while ago and my understanding was that he reached out to > Al and got the ack (after some ghosting on Al's behalf). I apologize > if I got that wrong -- all this happened in the middle of Jeff > transitioning his maintainership duties. >=20 Actually, I never got a formal ack from Al. I did send it repeatedly, but I assume he has been too busy to respond. We've had it sitting in linux-next for a couple of months, and he did suggest that approach in the first place, but I too would also prefer to see his official ack on it. > >=20 > > I've pulled this because I suspect that d_same_name() thing is fine, > > and I think the VM_WARN_ON_FOLIO() addition is completely wrong but > > not horrendous. > >=20 > > But you're on my tentative shit-list just for having claimed to have > > appropriate acks and having been found wanting. > >=20 > > Just for your information: fs/dcache.c is some of the most optimized > > code in the kernel, and some of the subtlest. That RCU pathname lookup > > is serious business. You don't make changes to pathname lookup just > > willy nilly. There's a reason I start looking at individual patches > > when I see it in the diffstat. >=20 > Understood. >=20 > Thanks, >=20 > Ilya --=20 Jeff Layton