Re: [PATCH 2/2] generic: test swapfile creation, activation, and deactivation

[Eryu Guan <guaneryu@gmail.com>]

On Tue, May 08, 2018 at 09:54:06AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Test swapfile activation and deactivation.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  tests/generic/708     |  152 +++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/708.out |   10 +++
>  tests/generic/group   |    1 
>  3 files changed, 163 insertions(+)
>  create mode 100755 tests/generic/708
>  create mode 100644 tests/generic/708.out
> 
> 
> diff --git a/tests/generic/708 b/tests/generic/708
> new file mode 100755
> index 00000000..48feeb25
> --- /dev/null
> +++ b/tests/generic/708
> @@ -0,0 +1,152 @@
> +#! /bin/bash
> +# FS QA Test No. 708
> +#
> +# Test various swapfile activation oddities.
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2018 Oracle.  All Rights Reserved.
> +#
> +# This program is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU General Public License as
> +# published by the Free Software Foundation.
> +#
> +# This program is distributed in the hope that it would be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program; if not, write the Free Software Foundation,
> +# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> +#
> +#-----------------------------------------------------------------------
> +
> +seq=`basename $0`
> +seqres=$RESULT_DIR/$seq
> +echo "QA output created by $seq"
> +
> +status=1	# failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> +	cd /
> +	rm -f $testfile
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +_supported_fs generic
> +_supported_os Linux
> +_require_scratch_swapfile
> +
> +rm -f $seqres.full
> +_scratch_mkfs >>$seqres.full 2>&1
> +_scratch_mount >>$seqres.full 2>&1
> +
> +swapfile=$SCRATCH_MNT/swap
> +len=$((2 * 1048576))
> +
> +swapfile_cycle() {
> +	local swapfile="$1"
> +
> +	mkswap $swapfile >> $seqres.full
> +	filefrag -v $swapfile >> $seqres.full
> +	swapon $swapfile 2>&1 | _filter_scratch
> +	swapon -v --bytes >> $seqres.full
> +	swapoff $swapfile 2>> $seeqres.full
> +	rm -f $swapfile
> +}
> +
> +test_can_falloc_swap() {
> +	local test_swapfile=$TEST_DIR/swapfile
> +
> +	echo "can we fallocate swap?"
> +	$XFS_IO_PROG -f -c "falloc 0 64k" $test_swapfile

mkswap(8) says "mkswap refuses areas smaller than 10 pages", so I
suspect 64k won't work for hosts with larger page size, e.g. ppc64, even
if the kernel supports swapfile on fallocated file. But I don't have the
hardware to actually try it..

> +	test -f $test_swapfile || return 1
> +	mkswap $test_swapfile
> +	swapon $test_swapfile
> +	res=$?
> +	swapoff $test_swapfile
> +	rm -f $test_swapfile
> +	return $res
> +}

When 'test_can_falloc_swap' returns non-zero, how could we tell if it's
because the kernel doesn't support swap on fallocate file or it's a
regression bug in the swap on fallocate file code?


And the kernel patch says "This enables XFS to support fallocate'd swap
files and swap files on realtime devices." So xfs/419 would start to
fail when the patch lands in upstream?

Thanks,
Eryu

> +
> +unset can_falloc_swap
> +test_can_falloc_swap >> $seqres.full 2>&1 && can_falloc_swap=yes
> +page_size=$(get_page_size)
> +
> +# Create a sparse swap file
> +echo "sparse swap" | tee -a $seqres.full
> +$XFS_IO_PROG -f -c "truncate $len" $swapfile >> $seqres.full
> +swapfile_cycle $swapfile
> +
> +# Create a regular swap file
> +echo "regular swap" | tee -a $seqres.full
> +_pwrite_byte 0x58 0 $len $swapfile >> $seqres.full
> +swapfile_cycle $swapfile
> +
> +# Create a fallocated swap file
> +echo "fallocate swap" | tee -a $seqres.full
> +if [ "$can_falloc_swap" = "yes" ]; then
> +	$XFS_IO_PROG -f -c "falloc 0 $len" $swapfile >> $seqres.full
> +	swapfile_cycle $swapfile
> +fi
> +
> +# Create a swap file with a little too much junk on the end
> +echo "too long swap" | tee -a $seqres.full
> +_pwrite_byte 0x58 0 $((len + 3)) $swapfile >> $seqres.full
> +swapfile_cycle $swapfile
> +
> +# Create a swap file with a large discontiguous range(?)
> +echo "large discontig swap" | tee -a $seqres.full
> +_pwrite_byte 0x58 0 $((len * 2)) $swapfile >> $seqres.full
> +old_sz="$(stat -c '%s' $swapfile)"
> +$XFS_IO_PROG -c "fcollapse $((len / 2)) $len" $swapfile >> $seqres.full 2>&1
> +new_sz="$(stat -c '%s' $swapfile)"
> +if [ $old_sz -gt $new_sz ]; then
> +	swapfile_cycle $swapfile
> +fi
> +rm -f $swapfile
> +
> +# Create a swap file with a small discontiguous range(?)
> +echo "small discontig swap" | tee -a $seqres.full
> +_pwrite_byte 0x58 0 $((len + 1024)) $swapfile >> $seqres.full
> +old_sz="$(stat -c '%s' $swapfile)"
> +$XFS_IO_PROG -c "fcollapse 66560 1024" $swapfile >> $seqres.full 2>&1
> +new_sz="$(stat -c '%s' $swapfile)"
> +if [ $old_sz -gt $new_sz ]; then
> +	swapfile_cycle $swapfile
> +fi
> +rm -f $swapfile
> +
> +# Create a fallocated swap file and touch every other $PAGE_SIZE to create
> +# a mess of written/unwritten extent records
> +echo "mixed swap" | tee -a $seqres.full
> +if [ "$can_falloc_swap" = "yes" ]; then
> +	$XFS_IO_PROG -f -c "falloc 0 $len" $swapfile >> $seqres.full
> +	seq $page_size $((page_size * 2)) $len | while read offset; do
> +		_pwrite_byte 0x58 $offset 1 $swapfile >> $seqres.full
> +	done
> +	swapfile_cycle $swapfile
> +fi
> +
> +# Create a ridiculously small swap file; mkswap says the minimum is 40k.
> +# However, each swap file must be at least two pages long.
> +echo "tiny swap" | tee -a $seqres.full
> +tiny_len=40960
> +min_swap_size=$((page_size * 2))
> +if [ "$min_swap_size" -gt "$tiny_len" ]; then
> +	tiny_len=$min_swap_size
> +fi
> +_pwrite_byte 0x58 0 $tiny_len $swapfile >> $seqres.full
> +swapfile_cycle $swapfile
> +
> +status=0
> +exit
> diff --git a/tests/generic/708.out b/tests/generic/708.out
> new file mode 100644
> index 00000000..d6199b99
> --- /dev/null
> +++ b/tests/generic/708.out
> @@ -0,0 +1,10 @@
> +QA output created by 708
> +sparse swap
> +swapon: SCRATCH_MNT/swap: skipping - it appears to have holes.
> +regular swap
> +fallocate swap
> +too long swap
> +large discontig swap
> +small discontig swap
> +mixed swap
> +tiny swap
> diff --git a/tests/generic/group b/tests/generic/group
> index 505383f7..9f3a933e 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -489,3 +489,4 @@
>  484 auto quick
>  485 auto quick insert
>  486 auto quick attr
> +708 auto quick swapfile
>