From patchwork Fri Jul 14 14:56:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 13313763 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 AF2EFEB64DC for ; Fri, 14 Jul 2023 14:56:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236233AbjGNO4W (ORCPT ); Fri, 14 Jul 2023 10:56:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235897AbjGNO4V (ORCPT ); Fri, 14 Jul 2023 10:56:21 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 17BF730E2; Fri, 14 Jul 2023 07:56:08 -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 A9FE961D3D; Fri, 14 Jul 2023 14:56:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 11AF9C433C7; Fri, 14 Jul 2023 14:56:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689346567; bh=zmAYa29dmHVe2XcpQVulPtUQGjUYwU/DldFn3+lG6jQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GwSQF8ouXy8X5KnTZTAz877Bc+g4hMxhTc8xiwOotwzJBg2vV6IHvDHConaSMYd0H XHAgSeE80DUSYDd8E2Mn5mGpuaWmLoDY7mVsatVurZyOafx/7Uv4+T6xeZSZJlp5R0 TqPmq8rrB7W9gAZRAfX+2pYBXSiZ1IhKNnGWMadlRTdweXKIc1YnGLgxp77Jtgfn5J PNohNSVYXJIlbigADollQZBQ2ku2xiJ7Ukttgt5uQi6SY8HHgLj6DXZYq6ERZsh+Ns IB8kyrjjueZPEzUoNvqYMG2fxbdG4IREXt/b5q41n9JPuDKInfE4DGtPA2t+Q/ukQF +zHl6xKBLapkw== Date: Fri, 14 Jul 2023 07:56:06 -0700 From: "Darrick J. Wong" To: zlang@redhat.com Cc: linux-xfs@vger.kernel.org, fstests@vger.kernel.org, guan@eryu.me, mpatocka@redhat.com Subject: [PATCH] generic/558: avoid forkbombs on filesystems with many free inodes Message-ID: <20230714145606.GJ11442@frogsfrogsfrogs> References: <20230711202528.GB11442@frogsfrogsfrogs> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230711202528.GB11442@frogsfrogsfrogs> Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org 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 -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