Re: [PATCH 03/11] xfs: Check for extent overflow when trivally adding a new extent

Darrick J. Wong
2020-11-14T00:18:23Z

> Subject: xfs: Check for extent overflow when trivally adding a new extent

Why does patch 3 have the same subject as patch 2? This confused
my quiltish scripts. :(

On Fri, Nov 13, 2020 at 04:56:55PM +0530, Chandan Babu R wrote:
> Verify that XFS does not cause inode fork's extent count to overflow
> when adding a single extent while there's no possibility of splitting an
> existing mapping (limited to realtime files only).
>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
> ---
> tests/xfs/523 | 176 ++++++++++++++++++++++++++++++++++++++++++++++
> tests/xfs/523.out | 18 +++++
> tests/xfs/group | 1 +
> 3 files changed, 195 insertions(+)
> create mode 100755 tests/xfs/523
> create mode 100644 tests/xfs/523.out
>
> diff --git a/tests/xfs/523 b/tests/xfs/523
> new file mode 100755
> index 00000000..4f5b3584
> --- /dev/null
> +++ b/tests/xfs/523
> @@ -0,0 +1,176 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2020 Chandan Babu R. All Rights Reserved.
> +#
> +# FS QA Test 523
> +#
> +# Verify that XFS does not cause inode fork's extent count to overflow when
> +# adding a single extent while there's no possibility of splitting an existing
> +# mapping (limited to realtime files only).
> +#
> +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 /
> + _scratch_unmount >> $seqres.full 2>&1
> + test -e "$rtdev" && losetup -d $rtdev >> $seqres.full 2>&1
> + rm -f $tmp.* $TEST_DIR/$seq.rtvol
> +}
> +
> +# 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_test
> +_require_xfs_debug
> +_require_test_program "punch-alternating"
> +_require_xfs_io_error_injection "reduce_max_iextents"
> +_require_xfs_io_error_injection "bmap_alloc_minlen_extent"
> +_require_scratch_nocheck
> +
> +grow_rtinodes()
> +{
> + echo "* Test extending rt inodes"
> +
> + _scratch_mkfs | _filter_mkfs >> $seqres.full 2> $tmp.mkfs
> + . $tmp.mkfs
> +
> + echo "Create fake rt volume"
> + nr_bitmap_blks=25
> + nr_bits=$((nr_bitmap_blks * dbsize * 8))
> + rtextsz=$dbsize
> + rtdevsz=$((nr_bits * rtextsz))
> + truncate -s $rtdevsz $TEST_DIR/$seq.rtvol
> + rtdev=$(_create_loop_device $TEST_DIR/$seq.rtvol)
> +
> + echo "Format and mount rt volume"
> + export USE_EXTERNAL=yes
> + export SCRATCH_RTDEV=$rtdev

I'm frankly wondering if it's time to just turn this into a
_scratch_synthesize_rtvol helper or something.

> + _scratch_mkfs -d size=$((1024 * 1024 * 1024)) \
> + -r size=2M,extsize=${rtextsz} >> $seqres.full
> + _scratch_mount >> $seqres.full
> +
> + testfile=$SCRATCH_MNT/testfile
> +
> + echo "Consume free space"
> + dd if=/dev/zero of=${testfile} bs=${dbsize} >> $seqres.full 2>&1

Can you accomplish this with fallocate? Or better yet _fill_fs()?

> + sync
> +
> + echo "Create fragmented filesystem"
> + $here/src/punch-alternating $testfile >> $seqres.full
> + sync
> +
> + echo "Inject reduce_max_iextents error tag"
> + xfs_io -x -c 'inject reduce_max_iextents' $SCRATCH_MNT
> +
> + echo "Inject bmap_alloc_minlen_extent error tag"
> + xfs_io -x -c 'inject bmap_alloc_minlen_extent' $SCRATCH_MNT
> +
> + echo "Grow realtime volume"
> + xfs_growfs -r $SCRATCH_MNT >> $seqres.full 2>&1

$XFS_GROWFS_PROG, not xfs_growfs

> + if [[ $? == 0 ]]; then
> + echo "Growfs succeeded; should have failed."
> + exit 1
> + fi
> +
> + _scratch_unmount >> $seqres.full
> +
> + echo "Verify rbmino's and rsumino's extent count"
> + for rtino in rbmino rsumino; do
> + ino=$(_scratch_xfs_db -c sb -c "print $rtino")
> + ino=${ino##${rtino} = }
> + echo "$rtino = $ino" >> $seqres.full
> +
> + nextents=$(_scratch_get_iext_count $ino data || \
> + _fail "Unable to obtain inode fork's extent count")

Aha, you use this helper for the rt inodes too. Ok, disregard my
comments for patch 1.

> + if (( $nextents > 10 )); then
> + echo "Extent count overflow check failed: nextents = $nextents"
> + exit 1
> + fi
> + done
> +
> + echo "Check filesystem"
> + _check_xfs_filesystem $SCRATCH_DEV none $rtdev
> +
> + losetup -d $rtdev
> + rm -f $TEST_DIR/$seq.rtvol
> +
> + export USE_EXTERNAL=""
> + export SCRATCH_RTDEV=""
> +}
> +
> +rtfile_extend()
> +{
> + echo "* Test extending an rt file"
> +
> + _scratch_mkfs | _filter_mkfs >> $seqres.full 2> $tmp.mkfs
> + . $tmp.mkfs

Are these separate functionality tests? If so, should they be in
separate test files?

> +
> + echo "Create fake rt volume"
> + nr_blks=$((15 * 2))
> + rtextsz=$dbsize
> + rtdevsz=$((2 * nr_blks * rtextsz))
> + truncate -s $rtdevsz $TEST_DIR/$seq.rtvol
> + rtdev=$(_create_loop_device $TEST_DIR/$seq.rtvol)
> +
> + echo "Format and mount rt volume"
> + export USE_EXTERNAL=yes
> + export SCRATCH_RTDEV=$rtdev
> + _scratch_mkfs -d size=$((1024 * 1024 * 1024)) \
> + -r size=$rtdevsz >> $seqres.full
> + _scratch_mount >> $seqres.full
> +
> + echo "Inject reduce_max_iextents error tag"
> + xfs_io -x -c 'inject reduce_max_iextents' $SCRATCH_MNT

$XFS_IO_PROG, not xfs_io.

--D

> +
> + echo "Create fragmented file on rt volume"
> + testfile=$SCRATCH_MNT/testfile
> + for i in $(seq 0 2 $((nr_blks - 1))); do
> + xfs_io -Rf -c "pwrite $((i * dbsize)) $dbsize" -c fsync \
> + $testfile >> $seqres.full 2>&1
> + [[ $? != 0 ]] && break
> + done
> +
> + testino=$(stat -c "%i" $testfile)
> +
> + _scratch_unmount >> $seqres.full
> +
> + echo "Verify \$testfile's extent count"
> + nextents=$(_scratch_get_iext_count $testino data || \
> + _fail "Unable to obtain inode fork's extent count")
> + if (( $nextents > 10 )); then
> + echo "Extent count overflow check failed: nextents = $nextents"
> + exit 1
> + fi
> +
> + echo "Check filesystem"
> + _check_xfs_filesystem $SCRATCH_DEV none $rtdev
> +
> + losetup -d $rtdev
> + rm -f $TEST_DIR/$seq.rtvol
> +
> + export USE_EXTERNAL=""
> + export SCRATCH_RTDEV=""
> +}
> +
> +grow_rtinodes
> +rtfile_extend
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/xfs/523.out b/tests/xfs/523.out
> new file mode 100644
> index 00000000..16b4e0ad
> --- /dev/null
> +++ b/tests/xfs/523.out
> @@ -0,0 +1,18 @@
> +QA output created by 523
> +* Test extending rt inodes
> +Create fake rt volume
> +Format and mount rt volume
> +Consume free space
> +Create fragmented filesystem
> +Inject reduce_max_iextents error tag
> +Inject bmap_alloc_minlen_extent error tag
> +Grow realtime volume
> +Verify rbmino's and rsumino's extent count
> +Check filesystem
> +* Test extending an rt file
> +Create fake rt volume
> +Format and mount rt volume
> +Inject reduce_max_iextents error tag
> +Create fragmented file on rt volume
> +Verify $testfile's extent count
> +Check filesystem
> diff --git a/tests/xfs/group b/tests/xfs/group
> index 1831f0b5..018c70ef 100644
> --- a/tests/xfs/group
> +++ b/tests/xfs/group
> @@ -520,3 +520,4 @@
> 520 auto quick reflink
> 521 auto quick realtime growfs
> 522 auto quick quota
> +523 auto quick realtime growfs
> --
> 2.28.0
>