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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5DCE8EE49AB for ; Fri, 25 Aug 2023 21:53:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9FB86680014; Fri, 25 Aug 2023 17:53:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9ABFC68000E; Fri, 25 Aug 2023 17:53:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 84C41680014; Fri, 25 Aug 2023 17:53:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 75C3368000E for ; Fri, 25 Aug 2023 17:53:57 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 45F231605D1 for ; Fri, 25 Aug 2023 21:53:57 +0000 (UTC) X-FDA: 81163980114.26.1FBC553 Received: from mail-pg1-f176.google.com (mail-pg1-f176.google.com [209.85.215.176]) by imf05.hostedemail.com (Postfix) with ESMTP id 7933C100017 for ; Fri, 25 Aug 2023 21:53:54 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=fromorbit-com.20221208.gappssmtp.com header.s=20221208 header.b=cH08dFt6; dmarc=pass (policy=quarantine) header.from=fromorbit.com; spf=pass (imf05.hostedemail.com: domain of david@fromorbit.com designates 209.85.215.176 as permitted sender) smtp.mailfrom=david@fromorbit.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1693000435; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=EA93GbJhFaX1RD1S1v1NWvgWKkuCopUaLEmO6z67OS0=; b=yfNYWYuqY/Wf/qXs+kgWbI6bU+S07Dsx/0+xFAtSIXMaUt4666A6UMXGfVzjF5OX2AmeHC mlGCl02906HUtli2itYCuJrOlaMafvOddKdAyF6fe8z58jP5w3K1d0CawOqAcXJsX5Ahon yaFfd4emHQCTN3fQG/q2TfjVjmRupUI= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=fromorbit-com.20221208.gappssmtp.com header.s=20221208 header.b=cH08dFt6; dmarc=pass (policy=quarantine) header.from=fromorbit.com; spf=pass (imf05.hostedemail.com: domain of david@fromorbit.com designates 209.85.215.176 as permitted sender) smtp.mailfrom=david@fromorbit.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1693000435; a=rsa-sha256; cv=none; b=N2iQoxce0iSfQzsx89kIf6qkw6hVT2dx0n6/c760MWDz9p8aZJkSKYbtNn+vtTZUIYk9an xo2isg9d6rN2GVBUmwF5Thk0QLDahNt3vUm4qAc9WDQEqEzF67b8xjhR2ndsJh8QMXwwdH 4/hQZN72hORQIiNPqtfqVottg1usGj4= Received: by mail-pg1-f176.google.com with SMTP id 41be03b00d2f7-565f86ff4d1so781118a12.2 for ; Fri, 25 Aug 2023 14:53:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fromorbit-com.20221208.gappssmtp.com; s=20221208; t=1693000434; x=1693605234; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=EA93GbJhFaX1RD1S1v1NWvgWKkuCopUaLEmO6z67OS0=; b=cH08dFt6/4c3wH/stFXC+uGu5D8z0Csp+c9btLL74n40FUQC+soJCMHngcXZEBLgzm qybrDAhkHNIQidm6McS9k7OAisvjKsYcisQszCCpar5CuSiRIpSFGB178B7PZGJmjIVI 4C//pqzQHhkBzMUsweM/Ox4iwIPKOu4SLlyG1BwihVAd4isMoJvmKve8ppg0AFR80Lm5 +9HwDLBwFdO48zPf3pAy2OfApTkcKybUvjmHUA0hm0UnLP/VyyPd03hkf4rprWixbIcJ VF2B37IJ0D+t2NzeGs35vYm6/AeFMMVd3Duqbo/sN/EdZ49iAcVRSUTD7gvcubzYge+h CorA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693000434; x=1693605234; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=EA93GbJhFaX1RD1S1v1NWvgWKkuCopUaLEmO6z67OS0=; b=aMloqXCSWV3dKuWlfUvEq+QszuEjtOmdYvNJ4SW8rRAGtUMklCoVEJPBmjvtoHsq+D 0oVKuH0X4/22IXjIiDi/Oqw0kVqMo4sBPckH3NVboXhKt4wMIoCZ4wJX6xqfwZ4Y/UWP spB/vvevTV06m1zLskVK9RblONq+w0L2NTOq61jYsgQD+eTCgcQbvZiEAeMmUPsu3oVu WhETDua2NTPuc6NF/FIsEiN1g850/P8r6ewnwTsKfSm+hTKzGeF1YeJv9pI3NXyn4ckj prZvpwu1wK/YTYunY3xx7uHADNKX2EpenGdyq3BW68UyuMqhxxT2tyNPmrBm5YoyQ8T5 aHkQ== X-Gm-Message-State: AOJu0YztvXR78jFImsz6KqoMqxv+8xDdZHnSP6EIJRmk3UuUdE3cAg/p 8+wYGtHnypAhDT6Bq4OQSZ/alg== X-Google-Smtp-Source: AGHT+IGuXiZpaiaSoWbg0vAVB9MheRguVETxlh6z74Aponrqbg78kQHVeidygYbMeETEncHmOPB93Q== X-Received: by 2002:a17:90a:bf88:b0:263:5d25:150c with SMTP id d8-20020a17090abf8800b002635d25150cmr15563047pjs.29.1693000434105; Fri, 25 Aug 2023 14:53:54 -0700 (PDT) Received: from dread.disaster.area (pa49-195-66-88.pa.nsw.optusnet.com.au. [49.195.66.88]) by smtp.gmail.com with ESMTPSA id fz23-20020a17090b025700b0026b4decfe59sm2177778pjb.31.2023.08.25.14.53.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 25 Aug 2023 14:53:53 -0700 (PDT) Received: from dave by dread.disaster.area with local (Exim 4.96) (envelope-from ) id 1qZekY-006V5n-1X; Sat, 26 Aug 2023 07:53:50 +1000 Date: Sat, 26 Aug 2023 07:53:50 +1000 From: Dave Chinner To: Hao Xu Cc: io-uring@vger.kernel.org, Jens Axboe , Dominique Martinet , Pavel Begunkov , Christian Brauner , Alexander Viro , Stefan Roesch , Clay Harris , "Darrick J . Wong" , linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-cachefs@redhat.com, ecryptfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-unionfs@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, codalist@coda.cs.cmu.edu, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-mm@kvack.org, linux-nilfs@vger.kernel.org, devel@lists.orangefs.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-mtd@lists.infradead.org, Wanpeng Li Subject: Re: [PATCH 24/29] xfs: support nowait for xfs_buf_read_map() Message-ID: References: <20230825135431.1317785-1-hao.xu@linux.dev> <20230825135431.1317785-25-hao.xu@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230825135431.1317785-25-hao.xu@linux.dev> X-Rspam-User: X-Stat-Signature: m5edqcak4ju5ubf861br5t17isn6z3ig X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 7933C100017 X-HE-Tag: 1693000434-515427 X-HE-Meta: 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 aNwdY09A 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Aug 25, 2023 at 09:54:26PM +0800, Hao Xu wrote: > From: Hao Xu > > This causes xfstests generic/232 hung in umount process, waiting for ail > push, so I comment it for now, need some hints from xfs folks. > Not a real patch. > > Signed-off-by: Hao Xu > --- > fs/xfs/xfs_buf.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > index cdad80e1ae25..284962a9f31a 100644 > --- a/fs/xfs/xfs_buf.c > +++ b/fs/xfs/xfs_buf.c > @@ -828,6 +828,13 @@ xfs_buf_read_map( > trace_xfs_buf_read(bp, flags, _RET_IP_); > > if (!(bp->b_flags & XBF_DONE)) { > +// /* > +// * Let's bypass the _xfs_buf_read() for now > +// */ > +// if (flags & XBF_NOWAIT) { > +// xfs_buf_relse(bp); > +// return -EAGAIN; > +// } This is *fundamentally broken*, and apart from anything else breaks readahead. IF we asked for a read, we cannot instantiate the buffer and then *not issue any IO on it* and release it. That leaves an uninitialised buffer in memory, and there's every chance that something then trips over it and bad things happen. A buffer like this *must* be errored out and marked stale so that the next access to it will then re-initialise the buffer state and trigger any preparatory work that needs to be done for the new operation. This comes back to my first comments that XBF_TRYLOCK cannot simpy be replaced with XBF_NOWAIT semantics... -Dave. -- Dave Chinner david@fromorbit.com