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 0BEEDEB64DC for ; Mon, 17 Jul 2023 15:28:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229458AbjGQP2b (ORCPT ); Mon, 17 Jul 2023 11:28:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232174AbjGQP1z (ORCPT ); Mon, 17 Jul 2023 11:27:55 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7533B1981; Mon, 17 Jul 2023 08:27:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D86B0610F4; Mon, 17 Jul 2023 15:27:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42C35C433C9; Mon, 17 Jul 2023 15:27:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689607641; bh=vEkCPmlJXf55N+JwD1MFNsxxP9a3sITW3xFdPQpMDYo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=G6vxHdjVbShYLWwxDDd/kvmyLYlTvxoedfH/sYjmV0M1hDuPcumcOYjOeb97OPv5H IzSm1tDGkdq0enWdEURxkHCrVpA4DC62BSSYJhFHldwQCQKBIDPh0oOk+ri+/4VyuC 3ryY69jFXu0o2Ck7haucKCwq3X77H/oRW17ns1v3aQBjlCen9FniKQXNYUEfpO+san Se2gXL2LU1uRcwvIJ8F+GVWzoa/ZLqs1x6xlcBvzPvHKiou43duPH/6MENAnVkoNJ5 wP1KvFpF98Z/sTWtrTBxxfbbvslD9u6LYcB1mf2q/OutJzRGkGnVgwAW/UGupsHqdn Ms0V+P/X3jcVQ== Date: Mon, 17 Jul 2023 08:27:20 -0700 From: "Darrick J. Wong" To: Zorro Lang Cc: linux-xfs@vger.kernel.org, fstests@vger.kernel.org, mpatocka@redhat.com Subject: Re: [PATCH] generic/558: avoid forkbombs on filesystems with many free inodes Message-ID: <20230717152720.GB11340@frogsfrogsfrogs> References: <20230714145900.GM11442@frogsfrogsfrogs> <20230717030303.i3stvautu3oh55ao@zlang-mailbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230717030303.i3stvautu3oh55ao@zlang-mailbox> Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org On Mon, Jul 17, 2023 at 11:03:03AM +0800, Zorro Lang wrote: > On Fri, Jul 14, 2023 at 07:59:00AM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > Mikulas reported that this test became a forkbomb on his system when he > > tested it with bcachefs. Unlike XFS and ext4, which have large inodes > > consuming hundreds of bytes, bcachefs has very tiny ones. Therefore, it > > reports a large number of free inodes on a freshly mounted 1GB fs (~15 > > million), which causes this test to try to create 15000 processes. > > > > There's really no reason to do that -- all this test wanted to do was to > > exhaust the number of inodes as quickly as possible using all available > > CPUs, and then it ran xfs_repair to try to reproduce a bug. Set the > > number of subshells to 4x the CPU count and spread the work among them > > instead of forking thousands of processes. > > > > Reported-by: Mikulas Patocka > > Signed-off-by: Darrick J. Wong > > Tested-by: Mikulas Patocka > > --- > > tests/generic/558 | 18 ++++++++++++------ > > 1 file changed, 12 insertions(+), 6 deletions(-) > > > > diff --git a/tests/generic/558 b/tests/generic/558 > > index 4e22ce656b..de5c28d00d 100755 > > --- a/tests/generic/558 > > +++ b/tests/generic/558 > > @@ -39,15 +39,21 @@ _scratch_mkfs_sized $((1024 * 1024 * 1024)) >>$seqres.full 2>&1 > > _scratch_mount > > > > i=0 > > -free_inode=`_get_free_inode $SCRATCH_MNT` > > -file_per_dir=1000 > > -loop=$((free_inode / file_per_dir + 1)) > > +free_inodes=$(_get_free_inode $SCRATCH_MNT) > > +nr_cpus=$(( $($here/src/feature -o) * 4 * LOAD_FACTOR )) > > +echo "free inodes: $free_inodes nr_cpus: $nr_cpus" >> $seqres.full > > + > > +if ((free_inodes <= nr_cpus)); then > > + nr_cpus=1 > > + files_per_dir=$free_inodes > > +else > > + files_per_dir=$(( (free_inodes + nr_cpus - 1) / nr_cpus )) > > +fi > > mkdir -p $SCRATCH_MNT/testdir > > > > echo "Create $((loop * file_per_dir)) files in $SCRATCH_MNT/testdir" >>$seqres.full > > Has the $loop been removed? DOH. v3 on the way. I hate bash. --D > > -while [ $i -lt $loop ]; do > > - create_file $SCRATCH_MNT/testdir $file_per_dir $i >>$seqres.full 2>&1 & > > - let i=$i+1 > > +for ((i = 0; i < nr_cpus; i++)); do > > + create_file $SCRATCH_MNT/testdir $files_per_dir $i >>$seqres.full 2>&1 & > > done > > wait > > > > >