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

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Mar 04, 2021 at 05:28:30PM +0530, Chandan Babu R wrote:
> 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.

That kind of regression will cause bug reports.  Can you make it so that
fstests skips the test if the rt mount fails?  e.g.

_try_scratch_mount || _notrun "Couldn't mount fs with synthetic rt volume"

--D

> 
> >
> >> +
> >> +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