Re: [PATCH] overlay: copy-up lowerdir which has opaque xattr set

[Eryu Guan <eguan@redhat.com>]

On Tue, Aug 09, 2016 at 04:37:30PM +1000, Dave Chinner wrote:
> On Tue, Aug 09, 2016 at 01:23:53AM +0800, Eryu Guan wrote:
> > When copying up a directory with opaque xattr set, the xattr was
> > copied up as well, after a remount the opaque flag is honored so the
> > copied-up directory is treated as opaque, which causes files created
> > in the lowerdir to be hidden when using multiple lower directories.
> > 
> > This is fixed by "ovl: don't copy up opaqueness".
> > 
> > Signed-off-by: Eryu Guan <eguan@redhat.com>
> > ---
> >  tests/overlay/014     | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++
> >  tests/overlay/014.out |  3 ++
> >  tests/overlay/group   |  1 +
> >  3 files changed, 100 insertions(+)
> >  create mode 100755 tests/overlay/014
> >  create mode 100644 tests/overlay/014.out
> > 
> > diff --git a/tests/overlay/014 b/tests/overlay/014
> > new file mode 100755
> > index 0000000..d9d8b5d
> > --- /dev/null
> > +++ b/tests/overlay/014
> > @@ -0,0 +1,96 @@
> > +#! /bin/bash
> > +# FS QA Test 014
> > +#
> > +# Test copy-up of lowerdir with opaque xattr set.
> > +#
> > +# When copying up a directory with opaque xattr set, the xattr was copied up as
> > +# well, after a remount the opaque flag is honored so the copied-up directory
> > +# is treated as opaque, which causes files created in the lowerdir to be hidden
> > +# when using multiple lower directories.
> > +#
> > +# This is fixed by "ovl: don't copy up opaqueness".
> > +#
> > +#-----------------------------------------------------------------------
> > +# 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 $seqres.full
> > +
> > +# real QA test starts here
> > +_supported_fs overlay
> > +_supported_os Linux
> > +_require_test
> > +_require_scratch
> > +_require_attrs
> > +
> > +# Remove all files from previous tests
> > +_scratch_mkfs
> > +
> > +# Create multiple lowerdirs and upperdir, workdir, and testdir on lowerdir
> > +lowerdir1=$SCRATCH_DEV/lower1
> > +lowerdir2=$SCRATCH_DEV/lower2
> > +upperdir=$SCRATCH_DEV/upper
> > +workdir=$SCRATCH_DEV/workdir
> > +mkdir -p $lowerdir1 $lowerdir2 $upperdir $workdir
> > +mkdir -p $lowerdir1/testdir/d
> > +
> > +# mount overlay with $lowerdir2 as upperdir, and remove & recreate testdir,
> > +# make testdir on $lowerdir2 opaque
> > +$MOUNT_PROG -t overlay -o lowerdir=$lowerdir1,upperdir=$lowerdir2 \
> > +	-o workdir=$workdir none $SCRATCH_MNT
> 
> We really need a _overlay_scratch_mount_dirs() function here. i.e.
> 
> _overlay_scratch_mount_dirs $lowerdir $upperdir $workdir
> 
> and factor the _overlay_scratch_mount/_overlay_mount code to
> use a single implemention of _overlay_mount_dirs()....

Sounds good to me. I'll see if I can write a new helper and convert
existing code to use this helper in a separate patch.

> 
> > +rm -rf $SCRATCH_MNT/testdir
> > +mkdir -p $SCRATCH_MNT/testdir/visibledir
> > +$UMOUNT_PROG $SCRATCH_MNT
> 
> _overlay_scratch_unmount

Okay.

Thanks for the review!

Eryu