Re: [PATCH 03/10] xfs: test rtalloc alignment and math errors

Chandan Babu R
2021-03-11T07:59:33Z

On 09 Mar 2021 at 10:10, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Add a couple of regression tests for "xfs: make sure the rt allocator
> doesn't run off the end" and "xfs: ensure that fpunch, fcollapse, and
> finsert operations are aligned to rt extent size".
>
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
> tests/xfs/759 | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> tests/xfs/759.out | 2 +
> tests/xfs/760 | 68 ++++++++++++++++++++++++++++++++++++
> tests/xfs/760.out | 9 +++++
> tests/xfs/group | 2 +
> 5 files changed, 181 insertions(+)
> create mode 100755 tests/xfs/759
> create mode 100644 tests/xfs/759.out
> create mode 100755 tests/xfs/760
> create mode 100644 tests/xfs/760.out
>
>
> diff --git a/tests/xfs/759 b/tests/xfs/759
> new file mode 100755
> index 00000000..8558fe30
> --- /dev/null
> +++ b/tests/xfs/759
> @@ -0,0 +1,100 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +# Copyright (c) 2021 Oracle. All Rights Reserved.
> +#
> +# FS QA Test No. 759
> +#
> +# This is a regression test for commit 2a6ca4baed62 ("xfs: make sure the rt
> +# allocator doesn't run off the end") which fixes an overflow error in the
> +# _near realtime allocator. If the rt bitmap ends exactly at the end of a
> +# block and the number of rt extents is large enough to allow an allocation
> +# request larger than the maximum extent size, it's possible that during a
> +# large allocation request, the allocator will fail to constrain maxlen on the
> +# second run through the loop, and the rt bitmap range check will run right off
> +# the end of the rtbitmap file. When this happens, xfs triggers a verifier
> +# error and returns EFSCORRUPTED.
> +
> +seq=`basename $0`
> +seqres=$RESULT_DIR/$seq
> +echo "QA output created by $seq"
> +
> +here=`pwd`
> +tmp=/tmp/$$
> +status=1 # failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> + cd /
> + rm -f $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +
> +# real QA test starts here
> +_supported_fs xfs
> +_require_scratch
> +_require_realtime
> +_require_test_program "punch-alternating"
> +
> +rm -f $seqres.full
> +
> +# Format filesystem to get the block size
> +_scratch_mkfs > $seqres.full
> +_scratch_mount >> $seqres.full
> +
> +blksz=$(_get_block_size $SCRATCH_MNT)
> +rextsize=$($XFS_INFO_PROG $SCRATCH_MNT | grep realtime.*extsz | sed -e 's/^.*extsz=\([0-9]*\).*$/\1/g')
> +rextblks=$((rextsize / blksz))
> +
> +echo "blksz $blksz rextsize $rextsize rextblks $rextblks" >> $seqres.full
> +
> +_scratch_unmount
> +
> +# Format filesystem with a realtime volume whose size fits the following:
> +# 1. Longer than (XFS MAXEXTLEN * blocksize) bytes.

Shouldn't the multiplier be RT extent size rather than FS block size?

> +# 2. Exactly a multiple of (NBBY * blksz * rextsize) bytes.

i.e The bits in one rt bitmap block map (NBBY * blksz * rextsize) bytes of an
rt device. Hence to have the bitmap end at a fs block boundary the
corresponding rt device size should be a multiple of this product. Is my
understanding correct?

> +
> +rtsize1=$((2097151 * blksz))
> +rtsize2=$((8 * blksz * rextsize))
> +rtsize=$(( $(blockdev --getsz $SCRATCH_RTDEV) * 512 ))
> +
> +echo "rtsize1 $rtsize1 rtsize2 $rtsize2 rtsize $rtsize" >> $seqres.full
> +
> +test $rtsize -gt $rtsize1 || \
> + _notrun "scratch rt device too small, need $rtsize1 bytes"
> +test $rtsize -gt $rtsize2 || \
> + _notrun "scratch rt device too small, need $rtsize2 bytes"
> +
> +rtsize=$((rtsize - (rtsize % rtsize2)))
> +

--
chandan