Re: [PATCH V6 12/13] xfs: Check for extent overflow when swapping extents

[Allison Henderson <allison.henderson@oracle.com>]

On 3/8/21 10:01 PM, Chandan Babu R wrote:
> This test verifies that XFS does not cause inode fork's extent count to
> overflow when swapping forks across two files.
> 
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Makes sense.  The extent illustrations help
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>

> ---
>   tests/xfs/536     | 105 ++++++++++++++++++++++++++++++++++++++++++++++
>   tests/xfs/536.out |  13 ++++++
>   tests/xfs/group   |   1 +
>   3 files changed, 119 insertions(+)
>   create mode 100755 tests/xfs/536
>   create mode 100644 tests/xfs/536.out
> 
> diff --git a/tests/xfs/536 b/tests/xfs/536
> new file mode 100755
> index 00000000..9bb4094a
> --- /dev/null
> +++ b/tests/xfs/536
> @@ -0,0 +1,105 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2021 Chandan Babu R.  All Rights Reserved.
> +#
> +# FS QA Test 536
> +#
> +# Verify that XFS does not cause inode fork's extent count to overflow when
> +# swapping forks between files
> +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
> +. ./common/inject
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +
> +_supported_fs xfs
> +_require_scratch
> +_require_xfs_debug
> +_require_xfs_scratch_rmapbt
> +_require_xfs_io_command "fcollapse"
> +_require_xfs_io_command "swapext"
> +_require_xfs_io_error_injection "reduce_max_iextents"
> +
> +echo "* Swap extent forks"
> +
> +echo "Format and mount fs"
> +_scratch_mkfs >> $seqres.full
> +_scratch_mount >> $seqres.full
> +
> +bsize=$(_get_block_size $SCRATCH_MNT)
> +
> +srcfile=${SCRATCH_MNT}/srcfile
> +donorfile=${SCRATCH_MNT}/donorfile
> +
> +echo "Create \$donorfile having an extent of length 67 blocks"
> +$XFS_IO_PROG -f -s -c "pwrite -b $((17 * bsize)) 0 $((17 * bsize))" $donorfile \
> +       >> $seqres.full
> +
> +# After the for loop the donor file will have the following extent layout
> +# | 0-4 | 5 | 6 | 7 | 8 | 9 | 10 |
> +echo "Fragment \$donorfile"
> +for i in $(seq 5 10); do
> +	start_offset=$((i * bsize))
> +	$XFS_IO_PROG -f -c "fcollapse $start_offset $bsize" $donorfile >> $seqres.full
> +done
> +
> +echo "Create \$srcfile having an extent of length 18 blocks"
> +$XFS_IO_PROG -f -s -c "pwrite -b $((18 * bsize)) 0 $((18 * bsize))" $srcfile \
> +       >> $seqres.full
> +
> +echo "Fragment \$srcfile"
> +# After the for loop the src file will have the following extent layout
> +# | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7-10 |
> +for i in $(seq 1 7); do
> +	start_offset=$((i * bsize))
> +	$XFS_IO_PROG -f -c "fcollapse $start_offset $bsize" $srcfile >> $seqres.full
> +done
> +
> +echo "Collect \$donorfile's extent count"
> +donor_nr_exts=$(_xfs_get_fsxattr nextents $donorfile)
> +
> +echo "Collect \$srcfile's extent count"
> +src_nr_exts=$(_xfs_get_fsxattr nextents $srcfile)
> +
> +echo "Inject reduce_max_iextents error tag"
> +_scratch_inject_error reduce_max_iextents 1
> +
> +echo "Swap \$srcfile's and \$donorfile's extent forks"
> +$XFS_IO_PROG -f -c "swapext $donorfile" $srcfile >> $seqres.full 2>&1
> +
> +echo "Check for \$donorfile's extent count overflow"
> +nextents=$(_xfs_get_fsxattr nextents $donorfile)
> +
> +if (( $nextents == $src_nr_exts )); then
> +	echo "\$donorfile: Extent count overflow check failed"
> +fi
> +
> +echo "Check for \$srcfile's extent count overflow"
> +nextents=$(_xfs_get_fsxattr nextents $srcfile)
> +
> +if (( $nextents == $donor_nr_exts )); then
> +	echo "\$srcfile: Extent count overflow check failed"
> +fi
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/xfs/536.out b/tests/xfs/536.out
> new file mode 100644
> index 00000000..f550aa1e
> --- /dev/null
> +++ b/tests/xfs/536.out
> @@ -0,0 +1,13 @@
> +QA output created by 536
> +* Swap extent forks
> +Format and mount fs
> +Create $donorfile having an extent of length 67 blocks
> +Fragment $donorfile
> +Create $srcfile having an extent of length 18 blocks
> +Fragment $srcfile
> +Collect $donorfile's extent count
> +Collect $srcfile's extent count
> +Inject reduce_max_iextents error tag
> +Swap $srcfile's and $donorfile's extent forks
> +Check for $donorfile's extent count overflow
> +Check for $srcfile's extent count overflow
> diff --git a/tests/xfs/group b/tests/xfs/group
> index aed06494..ba674a58 100644
> --- a/tests/xfs/group
> +++ b/tests/xfs/group
> @@ -533,3 +533,4 @@
>   533 auto quick
>   534 auto quick reflink
>   535 auto quick reflink
> +536 auto quick
>