Re: [PATCH] overlay: test basic whiteout

[Eryu Guan <eguan@redhat.com>]

On Thu, Apr 21, 2016 at 08:23:58PM +0800, Xiong Zhou wrote:
> Overlayfs whiteout can be visible if underlying xfs was created
> with ftype=0. Kernel commit
> 	45aebea (ovl: Ensure upper filesystem supports d_type)
> prevents mounting overlayfs like this since v4.6-rc1. No harm to
> keep this test as a sanity check.

It turns out that the test harness won't even start if underlying XFS
has no d_type support :)

mount: wrong fs type, bad option, bad superblock on /mnt/ovl/test,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.
common/rc: retrying test device mount with external set

But I still think it's good to have a whiteout sanity test.

> 
> Signed-off-by: Xiong Zhou <xzhou@redhat.com>
> ---
>  tests/overlay/003     | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/overlay/003.out |  2 ++
>  tests/overlay/group   |  1 +
>  3 files changed, 81 insertions(+)
>  create mode 100755 tests/overlay/003
>  create mode 100644 tests/overlay/003.out
> 
> diff --git a/tests/overlay/003 b/tests/overlay/003
> new file mode 100755
> index 0000000..2401075
> --- /dev/null
> +++ b/tests/overlay/003
> @@ -0,0 +1,78 @@
> +#! /bin/bash
> +# FS QA Test 003
> +#
> +# Test overlayfs whiteout.
> +#
> +# Overlayfs whiteout can be visible if underlying xfs was created
> +# with ftype=0. Kernel commit
> +#	45aebea (ovl: Ensure upper filesystem supports d_type)
> +# prevents mounting overlayfs like this since v4.6-rc1. No harm to
> +# keep this test as a sanity check.
> +#
> +#-----------------------------------------------------------------------
> +# 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
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs overlay
> +_supported_os Linux
> +_require_scratch
> +
> +# Remove all files from previous tests
> +_scratch_mkfs
> +
> +# Create test file in lower dir
> +lowerdir=${SCRATCH_DEV}/${OVERLAY_LOWER_DIR}
> +mkdir -p $lowerdir
> +touch ${lowerdir}/test_file

I think as a whiteout sanity test, more file types can be tested here,
not only regular file, things like dir, hardlink, symlink, chardev,
blkdev and named pipe should be tested as well.

> +
> +_scratch_mount
> +
> +# whiteout file in overlay mount
> +rm -f ${SCRATCH_MNT}/test_file

Then all files can be removed here
rm -rf ${SCRATCH_MNT}/*

> +# it should not be listed
> +ls -l ${SCRATCH_MNT}/test_file 2>&1 | awk -F: '{print $NF}'

And no output expected here from ls
ls ${SCRATCH_MNT}/

> +
> +_scratch_unmount
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/overlay/003.out b/tests/overlay/003.out
> new file mode 100644
> index 0000000..83bafee
> --- /dev/null
> +++ b/tests/overlay/003.out
> @@ -0,0 +1,2 @@
> +QA output created by 003
> + No such file or directory

And probably we can change this to a simple "Silence is golden" and
print it from the test.

> diff --git a/tests/overlay/group b/tests/overlay/group
> index 84d164e..f671c67 100644
> --- a/tests/overlay/group
> +++ b/tests/overlay/group
> @@ -5,3 +5,4 @@
>  #
>  001 auto quick copyup
>  002 auto quick metadata
> +003 auto quick

Add a new "whiteout" group?

Thanks,
Eryu