Re: [PATCH] fstests: regression test for btrfs dio read repair

[Liu Bo <bo.li.liu@oracle.com>]

On Wed, Apr 12, 2017 at 10:42:47AM +0100, Filipe Manana wrote:
> On Wed, Apr 12, 2017 at 2:27 AM, Liu Bo <bo.li.liu@oracle.com> wrote:
> > This case tests whether dio read can repair the bad copy if we have
> > a good copy.
> 
> Regardless of being a test we should have always had (thanks for
> this!), it would be useful to mention we had a regression (as the test
> description in the btrfs/140 file says) and which patch fixed it (and
> possibly which kernel version or patch/commit introduced the
> regression).
>

Sure, thanks for the review.

> Just a comment/question below.
> 
> >
> > Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> > ---
> >  tests/btrfs/140     | 152 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  tests/btrfs/140.out |  39 ++++++++++++++
> >  tests/btrfs/group   |   1 +
> >  3 files changed, 192 insertions(+)
> >  create mode 100755 tests/btrfs/140
> >  create mode 100644 tests/btrfs/140.out
> >
> > diff --git a/tests/btrfs/140 b/tests/btrfs/140
> > new file mode 100755
> > index 0000000..db56123
> > --- /dev/null
> > +++ b/tests/btrfs/140
> > @@ -0,0 +1,152 @@
> > +#! /bin/bash
> > +# FS QA Test 140
> > +#
> > +# Regression test for btrfs DIO read's repair during read.
> > +#
> > +#-----------------------------------------------------------------------
> > +# Copyright (c) 2017 Liu Bo.  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 $seqres.full
> > +
> > +# real QA test starts here
> > +
> > +# Modify as appropriate.
> > +_supported_fs btrfs
> > +_supported_os Linux
> > +_require_scratch_dev_pool 2
> > +_require_command "$BTRFS_MAP_LOGICAL_PROG" btrfs-map-logical
> > +_require_command "$FILEFRAG_PROG" filefrag
> > +_require_odirect
> > +
> > +# helpe to convert 'file offset' to btrfs logical offset
> > +FILEFRAG_FILTER='
> > +       if (/blocks? of (\d+) bytes/) {
> > +               $blocksize = $1;
> > +               next
> > +       }
> > +       ($ext, $logical, $physical, $length) =
> > +               (/^\s*(\d+):\s+(\d+)..\s+\d+:\s+(\d+)..\s+\d+:\s+(\d+):/)
> > +       or next;
> > +       ($flags) = /.*:\s*(\S*)$/;
> > +       print $physical * $blocksize, "#",
> > +             $length * $blocksize, "#",
> > +             $logical * $blocksize, "#",
> > +             $flags, " "'
> > +
> > +# this makes filefrag output script readable by using a perl helper.
> > +# output is one extent per line, with three numbers separated by '#'
> > +# the numbers are: physical, length, logical (all in bytes)
> > +# sample output: "1234#10#5678" -> physical 1234, length 10, logical 5678
> > +_filter_extents()
> > +{
> > +       tee -a $seqres.full | $PERL_PROG -ne "$FILEFRAG_FILTER"
> > +}
> > +
> > +_check_file_extents()
> > +{
> > +       cmd="filefrag -v $1"
> > +       echo "# $cmd" >> $seqres.full
> > +       out=`$cmd | _filter_extents`
> > +       if [ -z "$out" ]; then
> > +               return 1
> > +       fi
> > +       echo "after filter: $out" >> $seqres.full
> > +       echo $out
> > +       return 0
> > +}
> > +
> > +_check_repair()
> > +{
> > +       filter=${1:-cat}
> > +       dmesg | tac | sed -ne "0,\#run fstests $seqnum at $date_time#p" | tac | $filter | grep -q -e "csum failed"
> > +       if [ $? -eq 0 ]; then
> > +               echo 1
> > +       else
> > +               echo 0
> > +       fi
> > +}
> > +
> > +_scratch_dev_pool_get 2
> > +# step 1, create a raid1 btrfs which contains one 128k file.
> > +echo "step 1......mkfs.btrfs" >>$seqres.full
> > +
> > +mkfs_opts="-d raid1"
> > +_scratch_pool_mkfs $mkfs_opts >>$seqres.full 2>&1
> > +
> > +_scratch_mount -o nospace_cache
> 
> Why do we need to mount without space cache?
> I don't see why nor I think it's obvious. A comment in the test
> mentioning why would be useful for everyone.
>

Thanks for spotting it, we can safely get rid of it, it's a leftover when I
convert it to a fstests case.

Thanks,

-liubo
> 
> > +
> > +$XFS_IO_PROG -f -d -c "pwrite -S 0xaa -b 128K 0 128K" "$SCRATCH_MNT/foobar" | _filter_xfs_io
> > +
> > +sync
> > +
> > +# step 2, corrupt the first 64k of one copy (on SCRATCH_DEV which is the first
> > +# one in $SCRATCH_DEV_POOL
> > +echo "step 2......corrupt file extent" >>$seqres.full
> > +
> > +extents=`_check_file_extents $SCRATCH_MNT/foobar`
> > +logical_in_btrfs=`echo ${extents} | cut -d '#' -f 1`
> > +physical_on_scratch=`$BTRFS_MAP_LOGICAL_PROG -l ${logical_in_btrfs} $SCRATCH_DEV | grep "$SCRATCH_DEV" | awk '{print $6}'`
> > +
> > +_scratch_unmount
> > +$XFS_IO_PROG -d -c "pwrite -S 0xbb -b 64K $physical_on_scratch 64K" $SCRATCH_DEV | _filter_xfs_io
> > +
> > +_scratch_mount -o nospace_cache
> > +
> > +# step 3, 128k dio read (this read can repair bad copy)
> > +echo "step 3......repair the bad copy" >>$seqres.full
> > +
> > +# since raid1 consists of two copies, and the following read may read the good
> > +# copy directly, so lets loop 10 times here and discard output that dio reads
> > +# give
> > +for i in `seq 1 10`; do
> > +       $XFS_IO_PROG -d -c "pread -b 128K 0 128K" "$SCRATCH_MNT/foobar" > /dev/null
> > +       repair=`_check_repair`
> > +       if [ $repair -eq 1 ]; then
> > +               break
> > +       fi
> > +done
> > +
> > +_scratch_unmount
> > +
> > +# check if the repair works
> > +$XFS_IO_PROG -d -c "pread -v -b 512 $physical_on_scratch 512" $SCRATCH_DEV | _filter_xfs_io
> > +
> > +_scratch_dev_pool_put
> > +# success, all done
> > +status=0
> > +exit
> > diff --git a/tests/btrfs/140.out b/tests/btrfs/140.out
> > new file mode 100644
> > index 0000000..d8e3856
> > --- /dev/null
> > +++ b/tests/btrfs/140.out
> > @@ -0,0 +1,39 @@
> > +QA output created by 140
> > +wrote 131072/131072 bytes at offset 0
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +wrote 65536/65536 bytes at offset 244056064
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +0e8c0000:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0010:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0020:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0030:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0040:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0050:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0060:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0070:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0080:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0090:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c00a0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c00b0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c00c0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c00d0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c00e0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c00f0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0100:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0110:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0120:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0130:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0140:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0150:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0160:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0170:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0180:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c0190:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c01a0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c01b0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c01c0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c01d0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c01e0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +0e8c01f0:  aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa  ................
> > +read 512/512 bytes at offset 244056064
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > diff --git a/tests/btrfs/group b/tests/btrfs/group
> > index 9d4b80b..1cb9c98 100644
> > --- a/tests/btrfs/group
> > +++ b/tests/btrfs/group
> > @@ -141,3 +141,4 @@
> >  137 auto quick send
> >  138 auto compress
> >  139 auto qgroup
> > +140 auto quick
> > --
> > 2.5.0
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> 
> -- 
> Filipe David Manana,
> 
> “Whether you think you can, or you think you can't — you're right.”