Re: [PATCH] fstests: xfs_fsr SWAPEXT fails when temp forkoff smaller than target

[Eryu Guan <eguan@redhat.com>]

On Sat, Dec 10, 2016 at 01:17:53AM +0800, Zorro Lang wrote:
> If there's a file under a parent dir, but before running xfs_fsr the
> parent dir's attr is changed(grown), and these attrs will be inherited
> by new files. Then xfs_fsr's temp file and target file will have
> different attrs.
> 
> At this moment, if the data already fill whole data area, then there
> is not enough space to move di_forkoff to data direction, swap the
> extents between temp and target file will fail.
> 
> Signed-off-by: Zorro Lang <zlang@redhat.com>
> ---
> 
> Hi,
> 
> The original case use SELinux to test. For common test, I change to use
> ACL. As my test, when inode size is 512 bytes(or more), it'll increase
> enough bytes to attr area, if add new default ACL attr.
> 
> The "enough bytes" I expect is 16+ bytes. Because an extent is 128 bits,
> I keep using extent data format, so the growing step is 16 bytes. When I
> try to fill whole data area, at last (di_forkoff - size of di_u) will be
> in [0, 16).
> 
> As my test, 256 bytes inode size can't always reproduce this bug(especially
> in RHEL-6). But 512 (or more) inode size can help that.
> 
> Thanks,
> Zorro
> 
>  tests/xfs/999     | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/xfs/999.out |   2 +
>  tests/xfs/group   |   1 +
>  3 files changed, 118 insertions(+)
>  create mode 100755 tests/xfs/999
>  create mode 100644 tests/xfs/999.out
> 
> diff --git a/tests/xfs/999 b/tests/xfs/999
> new file mode 100755
> index 0000000..d896287
> --- /dev/null
> +++ b/tests/xfs/999
> @@ -0,0 +1,115 @@
> +#! /bin/bash
> +# FS QA Test 999
> +#
> +# Test xfs_fsr when temp's attr is larger than the target attr area, and
> +# without enough room to move di_forkoff to date direction. Then it'll fail
> +# to swap extents between temp and target files.
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2016 Red Hat, Inc.  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
> +. ./common/attr
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +_supported_fs xfs
> +_supported_os Linux
> +_require_scratch
> +# need a user to set ACL
> +_require_user
> +_require_acls
> +_require_xfs_io_command "falloc"
> +
> +# use fixed attr test parameters, 512+ bytes inode size is helpful
> +# to alloc more default ACL space
> +_scratch_mkfs_xfs -i size=512,attr=2 >> $seqres.full 2>&1
> +# Manually mount to avoid effect from some mount options
> +mount $SCRATCH_DEV $SCRATCH_MNT

I think you can unset MOUNT_OPTS and SELINUX_MOUNT_OPTIONS and use
_scratch_mount, e.g.

# comments here
MOUNT_OPTS=""
SELINUX_MOUNT_OPTIONS=""
export MOUNT_OPTS SELINUX_MOUNT_OPTIONS
_scratch_mount

> +
> +rm -f $SCRATCH_MNT/$seq.test 2>/dev/null

SCRATCH_DEV was just created, there's no need to remove this test file.

> +# remove all default ACL
> +setfacl -k $SCRATCH_MNT
> +sync
> +touch $SCRATCH_MNT/$seq.test
> +INODE_NUM=`ls -i $SCRATCH_MNT/$seq.test | awk '{print $1}'`

I think it's time to introduce a new helper to get inode number and use
"stat -c %i" to implement it.

> +
> +# unmount SCRATCH_DEV to get the di_forkoff size
> +_scratch_unmount
> +FORK_OFF=`_scratch_xfs_db -c "inode $INODE_NUM" -c "print core.forkoff" | awk -F "=" '{print $2}'`
> +# the attributes are stored in the inode’s literal area starting a forkoff * 8
> +FORK_OFF=$((FORK_OFF * 8))
> +# an on-disk extent takes 128 bits = 16 bytes, get the max in-fork extents to
> +# keep using extent data format
> +MAX_EXTENTS=$((FORK_OFF / 16))
> +
> +mount $SCRATCH_DEV $SCRATCH_MNT
> +
> +# fragment the file by writing backwards, and alloc MAX_EXTENTS extents to
> +# make the di_u nearly/already touch the di_forkoff
> +for i in `seq $((MAX_EXTENTS - 1)) -1 0`; do
> +	$XFS_IO_PROG -f -c "falloc $((i * 262144)) 262144" \
> +		$SCRATCH_MNT/$seq.test >> $seqres.full
> +done

Any comments on this 256k size?

> +
> +# add new default ACL to $SCRATCH_MNT, for xfs_fsr will use a *temp* file
> +# which takes more di_a field (smaller di_forkoff than *target* file)
> +# Generally this operation need to grow attr area ~32 bytes
> +setfacl --set d:u:fsgqa:rwx,d:g:fsgqa:rwx,d:o:rwx $SCRATCH_MNT
> +sync
> +
> +# At this moment, xfs_fsr will hit below situation:
> +#
> +# target:         forkoff
> +#                    |
> +# +------------------v--------+
> +# |       di_u       |  di_a  |
> +# +------------------^--------+
> +#
> +# temp:       forkoff
> +#                |
> +# +--------------v------------+
> +# |       di_u   |     di_a   |
> +# +--------------^------------+
> +$XFS_FSR_PROG $SCRATCH_MNT/$seq.test

I saw xfs_fsr reported EINVAL on failure, so better to have some
comments on the failure behavior.

BTW, upstream 4.8.0 xfsprogs fails this test too, an xfsprogs
regression?

Thanks,
Eryu

> +
> +dmesg | tail -10 >> $seqres.full
> +echo "Silence is golden"
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/xfs/999.out b/tests/xfs/999.out
> new file mode 100644
> index 0000000..3b276ca
> --- /dev/null
> +++ b/tests/xfs/999.out
> @@ -0,0 +1,2 @@
> +QA output created by 999
> +Silence is golden
> diff --git a/tests/xfs/group b/tests/xfs/group
> index c237b50..ad01b8e 100644
> --- a/tests/xfs/group
> +++ b/tests/xfs/group
> @@ -334,3 +334,4 @@
>  345 auto quick clone
>  346 auto quick clone
>  347 auto quick clone
> +999 auto quick fsr
> -- 
> 2.7.4
> 
> --
> To unsubscribe from this list: send the line "unsubscribe fstests" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html