Re: [PATCH 09/11] xfs: Check for extent overflow when remapping an extent

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Nov 13, 2020 at 04:57:01PM +0530, Chandan Babu R wrote:
> This test verifies that XFS does not cause inode fork's extent count to
> overflow when remapping extents from one file's inode fork to another.
> 
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
> ---
>  tests/xfs/529     | 86 +++++++++++++++++++++++++++++++++++++++++++++++
>  tests/xfs/529.out |  8 +++++
>  tests/xfs/group   |  1 +
>  3 files changed, 95 insertions(+)
>  create mode 100755 tests/xfs/529
>  create mode 100644 tests/xfs/529.out
> 
> diff --git a/tests/xfs/529 b/tests/xfs/529
> new file mode 100755
> index 00000000..a44ce199
> --- /dev/null
> +++ b/tests/xfs/529
> @@ -0,0 +1,86 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2020 Chandan Babu R.  All Rights Reserved.
> +#
> +# FS QA Test 529
> +#
> +# Verify that XFS does not cause inode fork's extent count to overflow when
> +# remapping extents from one file's inode fork to another.
> +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/reflink
> +. ./common/inject
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +
> +_supported_fs xfs
> +_require_scratch
> +_require_scratch_reflink
> +_require_xfs_debug
> +_require_xfs_io_command "reflink"
> +_require_xfs_io_error_injection "reduce_max_iextents"
> +
> +echo "* Reflink remap extents"
> +
> +echo "Format and mount fs"
> +_scratch_mkfs >> $seqres.full
> +_scratch_mount >> $seqres.full
> +
> +bsize=$(_get_block_size $SCRATCH_MNT)
> +
> +srcfile=${SCRATCH_MNT}/srcfile
> +dstfile=${SCRATCH_MNT}/dstfile
> +
> +nr_blks=15
> +
> +echo "Create \$srcfile having an extent of length $nr_blks blocks"
> +xfs_io -f -c "pwrite -b $((nr_blks * bsize))  0 $((nr_blks * bsize))" \
> +       -c fsync $srcfile >> $seqres.full
> +
> +echo "Create \$dstfile having an extent of length $nr_blks blocks"
> +xfs_io -f -c "pwrite -b $((nr_blks * bsize))  0 $((nr_blks * bsize))" \
> +       -c fsync $dstfile >> $seqres.full
> +
> +echo "Inject reduce_max_iextents error tag"
> +xfs_io -x -c 'inject reduce_max_iextents' $SCRATCH_MNT
> +
> +echo "Reflink every other block from \$srcfile into \$dstfile"
> +for i in $(seq 1 2 $((nr_blks - 1))); do
> +	xfs_io -f -c "reflink $srcfile $((i * bsize)) $((i * bsize)) $bsize" \
> +	       $dstfile >> $seqres.full 2>&1
> +done
> +
> +ino=$(stat -c "%i" $dstfile)
> +
> +_scratch_unmount >> $seqres.full
> +
> +echo "Verify \$dstfile's extent count"
> +
> +nextents=$(_scratch_get_iext_count $ino data ||
> +		_fail "Unable to obtain inode fork's extent count")
> +if (( $nextents > 10 )); then
> +	echo "Extent count overflow check failed: nextents = $nextents"
> +fi

Generally looks fine, though many of the comments I've made about the
other patches (mkfs size, _get_file_block_size usage, etc.) apply here
too.

--D

> +# success, all done
> +status=0
> +exit
> diff --git a/tests/xfs/529.out b/tests/xfs/529.out
> new file mode 100644
> index 00000000..687a8bd2
> --- /dev/null
> +++ b/tests/xfs/529.out
> @@ -0,0 +1,8 @@
> +QA output created by 529
> +* Reflink remap extents
> +Format and mount fs
> +Create $srcfile having an extent of length 15 blocks
> +Create $dstfile having an extent of length 15 blocks
> +Inject reduce_max_iextents error tag
> +Reflink every other block from $srcfile into $dstfile
> +Verify $dstfile's extent count
> diff --git a/tests/xfs/group b/tests/xfs/group
> index c85aac6b..bc3958b3 100644
> --- a/tests/xfs/group
> +++ b/tests/xfs/group
> @@ -526,3 +526,4 @@
>  526 auto quick dir hardlink symlink
>  527 auto quick
>  528 auto quick reflink
> +529 auto quick reflink
> -- 
> 2.28.0
>