Re: [PATCH V4 03/11] xfs: Check for extent overflow when growing realtime bitmap/summary inodes

Chandan Babu R
2021-03-04T12:00:33Z

On 03 Mar 2021 at 23:15, Darrick J. Wong wrote:
> On Mon, Jan 18, 2021 at 11:50:14AM +0530, Chandan Babu R wrote:
>> Verify that XFS does not cause realtime bitmap/summary inode fork's
>> extent count to overflow when growing the realtime volume associated
>> with a filesystem.
>>
>> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
>> ---
>> tests/xfs/523 | 119 ++++++++++++++++++++++++++++++++++++++++++++++
>> tests/xfs/523.out | 11 +++++
>> tests/xfs/group | 1 +
>> 3 files changed, 131 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..145f0ff6
>> --- /dev/null
>> +++ b/tests/xfs/523
>> @@ -0,0 +1,119 @@
>> +#! /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 bitmap/summary inode fork's extent count to
>> +# overflow when growing an the realtime volume of the filesystem.
>> +#
>> +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
>> +. ./common/populate
>> +
>> +# 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
>
> Might want a comment about why this test doesn't _require_realtime.

Sure. I will do that.

>
> Hm. What /does/ happen if the kernel xfs driver wasn't built with
> realtime support? I'll investigate and report back.

_scratch_mount invocation later in the script fails and hence the script exits
with a failure status.

>
>> +
>> +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=$rtdev
>> +_scratch_mkfs -d size=$((1024 * 1024 * 1024)) \
>> + -r size=2M,extsize=${rtextsz} >> $seqres.full
>> +_scratch_mount >> $seqres.full
>> +
>> +echo "Consume free space"
>> +fillerdir=$SCRATCH_MNT/fillerdir
>> +nr_free_blks=$(stat -f -c '%f' $SCRATCH_MNT)
>> +nr_free_blks=$((nr_free_blks * 90 / 100))
>> +
>> +_fill_fs $((dbsize * nr_free_blks)) $fillerdir $dbsize 0 >> $seqres.full 2>&1
>> +
>> +echo "Create fragmented filesystem"
>> +for dentry in $(ls -1 $fillerdir/); do
>> + $here/src/punch-alternating $fillerdir/$dentry >> $seqres.full
>> +done
>> +
>> +echo "Inject reduce_max_iextents error tag"
>> +_scratch_inject_error reduce_max_iextents 1
>> +
>> +echo "Inject bmap_alloc_minlen_extent error tag"
>> +_scratch_inject_error bmap_alloc_minlen_extent 1
>> +
>> +echo "Grow realtime volume"
>> +$XFS_GROWFS_PROG -r $SCRATCH_MNT >> $seqres.full 2>&1
>> +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")
>> + 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=""
>
> No need to clear these, but with those two nits fixed, this looks all right.
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>

Thanks for the review!

I also noticed a bug in the script when it is executed on a 1k block sized
filesystem. The second invocation of _scratch_mkfs ends up creating a 4k
blocksized filesystem since the block size was not explicitly passed as an
argument. Also, if the block size is less than 4k, we have to set realtime
block size to 4k.

I have fixed these bugs and will include the fixes in the next version
of the patchset.

>
> --D
>
>> +
>> +# success, all done
>> +status=0
>> +exit
>> diff --git a/tests/xfs/523.out b/tests/xfs/523.out
>> new file mode 100644
>> index 00000000..7df02970
>> --- /dev/null
>> +++ b/tests/xfs/523.out
>> @@ -0,0 +1,11 @@
>> +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
>> 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
>> --
>> 2.29.2
>>

--
chandan