Message-ID: <20170105092812.GT1859@eguan.usersys.redhat.com>
Date:   Thu, 5 Jan 2017 17:28:12 +0800
From:   Eryu Guan <eguan@...hat.com>
To:     Roman Pen <roman.penyaev@...fitbricks.com>
Cc:     "Theodore Ts'o" <tytso@....edu>, linux-ext4@...r.kernel.org,
        fstests@...r.kernel.org
Subject: Re: [PATCH v2 1/1] xfstests: ext4/023: reproduces incorrect right
 shift (insert range)

On Wed, Jan 04, 2017 at 08:08:06PM +0100, Roman Pen wrote:
> Test tries to insert many blocks at the same offset to reproduce
> the following layout:
> 
>    block #0  block #1
>    |ext0 ext1|ext2 ext3 ...|
>         ^
>      insert of a new block
> 
> Because of an incorrect range first block is never reached,
> thus ext1 is untouched, resulting to a hole at a wrong offset:
> 
> What we got:
> 
>    block #0   block #1
>    |ext0 ext1|   ext2 ext3 ...|
>               ^
>               hole at a wrong offset
> 
> What we expect:
> 
>    block #0    block #1
>    |ext0   ext1|ext2 ext3 ...|
>         ^
>         hole at a correct offset
> 
> Signed-off-by: Roman Pen <roman.penyaev@...fitbricks.com>
> Cc: "Theodore Ts'o <tytso@....edu>"
> Cc: linux-ext4@...r.kernel.org
> Cc: fstests@...r.kernel.org

Thanks for the test! A few comments inline.

> ---
> v1..v2:
> 
> '_require_xfs_io_command "finsert"' line was added to prevent
> the test to fail on "ext3", "bigalloc" and "bigalloc_1k"
> configurations.
> 
>  tests/ext4/023     | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/ext4/023.out |   2 +
>  tests/ext4/group   |   1 +
>  3 files changed, 128 insertions(+)
>  create mode 100755 tests/ext4/023
>  create mode 100644 tests/ext4/023.out
> 
> diff --git a/tests/ext4/023 b/tests/ext4/023
> new file mode 100755
> index 000000000000..2cd890731eb5
> --- /dev/null
> +++ b/tests/ext4/023
> @@ -0,0 +1,125 @@
> +#! /bin/bash
> +# FS QA Test 023
> +#
> +# Regression test which reproduces an incorrect right shift
> +# (insert range) for the first extent in a range.
> +#
> +# Test tries to insert many blocks at the same offset to reproduce
> +# the following layout:
> +#
> +#    block #0  block #1
> +#    |ext0 ext1|ext2 ext3 ...|
> +#         ^
> +#      insert of a new block
> +#
> +# Because of an incorrect range first block is never reached,
> +# thus ext1 is untouched, resulting to a hole at a wrong offset:
> +#
> +# What we got:
> +#
> +#    block #0   block #1
> +#    |ext0 ext1|   ext2 ext3 ...|
> +#               ^
> +#               hole at a wrong offset
> +#
> +# What we expect:
> +#
> +#    block #0    block #1
> +#    |ext0   ext1|ext2 ext3 ...|
> +#         ^
> +#         hole at a correct offset
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2017 Roman Penyaev.  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"
> +
> +here=`pwd`
> +tmp=/tmp/$$
> +status=1	# failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> +	cd /
> +	rm -f $tmp.*
> +}
> +
> +# 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
> +
> +# Modify as appropriate.
> +_supported_fs ext4

This test can be made generic, there's nothing ext4-specific in this
test, and you can use helper function "get_block_size" to query
filesystem blocksize, so ..

> +_supported_os Linux
> +_require_test
> +_require_dumpe2fs

no need to require & use dumpe2fs.

> +_require_xfs_io_command "finsert"
> +
> +pattern=$tmp
> +testfile=$TEST_DIR/023.file

Use $seq number not hardcoded number. e.g.

testfile=$TEST_DIR/$seq.file

> +
> +blksize=`$DUMPE2FS_PROG -h $TEST_DEV 2>/dev/null | grep "Block size" | \
> +	awk '{print $3}'`

blksize=`get_block_size $TEST_DIR`

> +
> +# Generate a block with a repeating number represented as 4 bytes decimal.
> +function generate_pattern() {
> +	blkind=$1
> +	printf "%04d" $blkind | awk  '{ while (c++ < '$(($blksize/4))') \
> +		printf "%s", $0 }' > $pattern
> +}

I don't think this is necessary, see below

> +
> +echo -n > $testfile
> +$XFS_IO_PROG -c "falloc 0 $(($blksize * 2))" $testfile \
> +			 >> $seqres.full 2>&1

$XFS_IO_PROG -f -c "...", -f option creates the file for you if it's not
existed :)

> +
> +# First block, has 0001 as a pattern
> +generate_pattern 1
> +$XFS_IO_PROG -c "pwrite -i $pattern        0 $blksize" $testfile \
> +			 >> $seqres.full 2>&1
> +
> +# Second block, has 0002 as a pattern
> +generate_pattern 2
> +$XFS_IO_PROG -c "pwrite -i $pattern $blksize $blksize" $testfile \
> +			 >> $seqres.full 2>&1
> +
> +# Insert 998 blocks after the first block
> +for (( block=3; block<=1000; block++ )); do
> +	$XFS_IO_PROG -c "finsert $blksize $blksize" $testfile \
> +				 >> $seqres.full 2>&1
> +
> +	generate_pattern $block
> +	$XFS_IO_PROG -c "pwrite -i $pattern $blksize $blksize" $testfile \
> +				 >> $seqres.full 2>&1
> +done

I think we can write any non-zero pattern to the file, and check if
there's any zero pattern in the file after doing all the insert & write
operations, because every zero block meant to be written by xfs_io in
the loop. If we see zero pattern, we know insert happens at the wrong
offset. So I'd suggest something like:

# First block, has 'a' as a pattern
$XFS_IO_PROG -fc "pwrite -S 0x61 0 $blksize" $testfile \
	>>$seqres.full 2>&1

# Second block, has 'b' as a pattern
$XFS_IO_PROG -fc "pwrite -S 0x62 $blksize $blksize" $testfile \
	>>$seqres.full 2>&1

# Insert 998 blocks after the first block and fill the block with 'c' as
# a pattern
for (( i=0; i<998; i++ )); do
	$XFS_IO_PROG -c "finsert $blksize $blksize" $testfile \
				 >> $seqres.full 2>&1
	$XFS_IO_PROG -c "pwrite -S 0x63 $blksize $blksize" $testfile \
				 >> $seqres.full 2>&1
done

# Dump the file but avoid offsets because block size can vary.
# No zero should be seen in the file
hexdump -e '16/1 "%_p" "\n"' $testfile

And .out file is like:

QA output created by 023
aaaaaaaaaaaaaaaa
*
cccccccccccccccc
*
bbbbbbbbbbbbbbbb
*

> +# Avoid offsets because block size can vary.
> +# Expected blocks content is the following:
> +#   0001 1000 0999 0998 ... 0002
> +hexdump -e '16/1 "%_p" "\n"' $testfile | md5sum
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/ext4/023.out b/tests/ext4/023.out
> new file mode 100644
> index 000000000000..383e305d43fa
> --- /dev/null
> +++ b/tests/ext4/023.out
> @@ -0,0 +1,2 @@
> +QA output created by 023
> +d1c3b6f63c5420ca8248ca380a8c00cb  -
> diff --git a/tests/ext4/group b/tests/ext4/group
> index 53fe03e87083..ace5cf1a3d47 100644
> --- a/tests/ext4/group
> +++ b/tests/ext4/group
> @@ -25,6 +25,7 @@
>  020 auto quick ioctl rw
>  021 auto quick
>  022 auto quick attr dangerous
> +023 auto quick

Can be in 'insert' group too.

Thanks,
Eryu

>  271 auto rw quick
>  301 aio auto ioctl rw stress
>  302 aio auto ioctl rw stress
> -- 
> 2.10.2
> 
> --
> To unsubscribe from this list: send the line "unsubscribe fstests" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists