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

Chandan Babu R
2020-11-17T14:22:12Z

On Saturday 14 November 2020 5:48:13 AM IST Darrick J. Wong wrote:
> > 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. :(

Sorry, The tests in patch 2 and 3 test the functionality associated with
XFS_IEXT_ADD_NOSPLIT_CNT. I had decided to separate these tests from those in
patch 2 since the tests here required creating an RT volume. I will fix the
subject line before posting the next version.

>
> 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.

Ok. I will write the helper and invoke it from appropriate places in xfstests.

>
> > + _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()?

Hmm. _fill_fs() would be a better candidate. I can then invoke
punch-alternating on all the files in the directory (passed as 2nd argument to
_fill_fs()) to create a fragmented filesystem. Thanks for the suggestion.

>
> > + 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

Ok. I will fix this.

>
> > + 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?

Actually I will drop the rtfile_extend() test functionality since it takes the
same code path as the direct IO file operation tested in patch 2.

>
> > +
> > + 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.

Ok. I will fix this in all the test scripts in this patchset.

>
> --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
>

--
chandan