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 CAB25C25B6E for ; Wed, 25 Oct 2023 22:05:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230176AbjJYWFq (ORCPT ); Wed, 25 Oct 2023 18:05:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229677AbjJYWFp (ORCPT ); Wed, 25 Oct 2023 18:05:45 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27269137; Wed, 25 Oct 2023 15:05:43 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BCEB5C433C8; Wed, 25 Oct 2023 22:05:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1698271542; bh=sXgCZDGvHjX5ThjhyGj/jyEl+TF9e+Epo8eZ2CaHRjg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YBLYuxak40DkVG6Nzny/S8oiHzZMKK6NzhdYr08HtKT62+cBPdhhbhu3+pjR2J1/q SNxpu24YfOVeaz+oYDL0/W7HCQzjF7kNfdekTJjW77wnpTMQdusST8kADahaEbqs1Y PzPU4OWcrIfWvih6K+eey6fW4pG1FD74mjiEZYSIikJUhpfHkl+tqmOLJpY2F/vQVB vtr5bMDuD6+PK2KIcEXzFfb7Pk68gd9rmZdOL5Du1ibCJ7c/IPPXkzzfDOJ8pgLP04 Q0zwcvXrB/N+H7A23QJ43F1hmBwPLzshyO7LSjV5BqI8lqitLBIWMR6vsc17ZN/G8j kHqHzEcyu5MYA== Date: Wed, 25 Oct 2023 15:05:42 -0700 From: "Darrick J. Wong" To: Omar Sandoval Cc: fstests@vger.kernel.org, linux-xfs@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH fstests] xfs: test refilling AGFL after lots of btree splits Message-ID: <20231025220542.GL11391@frogsfrogsfrogs> References: <013168d2de9d25c56fe45ad75e9257cf9664f2d6.1698190191.git.osandov@fb.com> <20231025152702.GE3195650@frogsfrogsfrogs> 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-xfs@vger.kernel.org On Wed, Oct 25, 2023 at 01:15:43PM -0700, Omar Sandoval wrote: > On Wed, Oct 25, 2023 at 08:27:02AM -0700, Darrick J. Wong wrote: > > On Tue, Oct 24, 2023 at 04:37:42PM -0700, Omar Sandoval wrote: > > > This is a regression test for patch "xfs: fix internal error from AGFL > > > exhaustion"), which is not yet merged. Without the fix, it will fail > > > with a "Structure needs cleaning" error. > > > > Will look at the actual code patch next... > > > > > Signed-off-by: Omar Sandoval > > > --- > > > tests/xfs/601 | 62 +++++++++++++++++++++++++++++++++++++++++++++++ > > > tests/xfs/601.out | 2 ++ > > > 2 files changed, 64 insertions(+) > > > create mode 100755 tests/xfs/601 > > > create mode 100644 tests/xfs/601.out > > > > > > diff --git a/tests/xfs/601 b/tests/xfs/601 > > > new file mode 100755 > > > index 00000000..bbc5b443 > > > --- /dev/null > > > +++ b/tests/xfs/601 > > > @@ -0,0 +1,62 @@ > > > +#! /bin/bash > > > +# SPDX-License-Identifier: GPL-2.0 > > > +# Copyright (c) Meta Platforms, Inc. and affiliates. > > > +# > > > +# FS QA Test 601 > > > +# > > > +# Regression test for patch "xfs: fix internal error from AGFL exhaustion". > > > +# > > > +. ./common/preamble > > > +_begin_fstest auto prealloc punch > > > + > > > +. ./common/filter > > > + > > > +_supported_fs xfs > > > +_require_scratch > > > +_require_test_program punch-alternating > > > +_fixed_by_kernel_commit XXXXXXXXXXXX "xfs: fix internal error from AGFL exhaustion" > > > + > > > +_scratch_mkfs -m rmapbt=0 | _filter_mkfs > /dev/null 2> "$tmp.mkfs" > > > > Need to probe if mkfs.xfs actually supports rmapbt options first, since > > this bug applies to old fses from before rmap even existed, right? > > Good point. Something like: > > opts= > if $MKFS_XFS_PROG |& grep rmapbt; then > opts="-m rmapbt=0" > fi > _scratch_mkfs $opts | _filter_mkfs > /dev/null 2> "$tmp.mkfs" Yep, that works. > > (Or: What changes are needed to make the reproducer work with rmapbt > > enabled?) > > We'd need to craft the filesystem in a way that a single operation > splits and adds a new level to the bnobt, cntbt, and rmapbt all at the > same time. It can probably be done, but I suspect it'd be much more > complicated :( > > > > +. "$tmp.mkfs" > > > +_scratch_mount > > > + > > > +alloc_block_len=$((_fs_has_crcs ? 56 : 16)) > > > +allocbt_leaf_maxrecs=$(((dbsize - alloc_block_len) / 8)) > > > +allocbt_node_maxrecs=$(((dbsize - alloc_block_len) / 12)) > > > + > > > +# Create a big file with a size such that the punches below create the exact > > > +# free extents we want. > > > +num_holes=$((allocbt_leaf_maxrecs * allocbt_node_maxrecs - 1)) > > > +$XFS_IO_PROG -c "falloc 0 $((9 * dbsize + num_holes * dbsize * 2))" -f "$SCRATCH_MNT/big" > > > > What happens if the allocations are all in some other AG? The scratch > > device could be 100TB. > > Yeah, this relies on all of the allocations going to AG 0, and the big > fallocate getting one contiguous extent. That always happened for me on > a few different sized filesystems, but I understand it's not guaranteed. > Maybe I should create the filesystem with -d agcount=1? Hmm. xfs_repair is likely to get cranky about single-AG filesystems... > > > +# Fill in any small free extents in AG 0. After this, there should be only one, > > > +# large free extent. > > > +_scratch_unmount > > > +mapfile -t gaps < <($XFS_DB_PROG -c 'agf 0' -c 'addr cntroot' -c 'p recs' "$SCRATCH_DEV" | > > > + $SED_PROG -rn 's/^[0-9]+:\[[0-9]+,([0-9]+)\].*/\1/p' | > > > + tac | tail -n +2) > > > > _scratch_xfs_db -c 'agf 0' -c 'addr cntroot' -c 'btdump' ? > > Will fix. > > > +_scratch_mount > > > +for gap_i in "${!gaps[@]}"; do > > > + gap=${gaps[$gap_i]} > > > + $XFS_IO_PROG -c "falloc 0 $((gap * dbsize))" -f "$SCRATCH_MNT/gap$gap_i" > > > +done ...but you could check that the AG 0 cntbt actually has one large free extent, as the comment says should be the case. > > > + > > > +# Create enough free space records to make the bnobt and cntbt both full, > > > +# 2-level trees, plus one more record to make them split all the way to the > > > +# root and become 3-level trees. After this, there is a 7-block free extent in > > > +# the rightmost leaf of the cntbt, and all of the leaves of the cntbt other > > > +# than the rightmost two are full. Without the fix, the free list is also > > > +# empty. > > > +$XFS_IO_PROG -c "fpunch $dbsize $((7 * dbsize))" "$SCRATCH_MNT/big" > > > +"$here/src/punch-alternating" -o 9 "$SCRATCH_MNT/big" > > > + > > > +# Do an arbitrary operation that refills the free list. Without the fix, this > > > +# will allocate 6 blocks from the 7-block free extent in the rightmost leaf of > > > +# the cntbt, then try to insert the remaining 1 block free extent in the > > > +# leftmost leaf of the cntbt. But that leaf is full, so this tries to split the > > > +# leaf and fails because the free list is empty. > > > +$XFS_IO_PROG -c "fpunch 0 $dbsize" "$SCRATCH_MNT/big" > > > + > > > +echo "Silence is golden" > > > > Without the fix applied, what happens now? Does fpunch fail with EIO > > to taint the golden output? > > It fails with EFSCORRUPTED/EUCLEAN and prints an error message as noted > in my commit message, yeah. Cool! Looking forward to the next revision. :) --D > > Thanks! > > Omar