Re: [PATCH] btrfs: default subvolume deletion test

[Omar Sandoval <osandov@osandov.com>]

On Tue, Jun 02, 2015 at 09:40:13PM -0700, Omar Sandoval wrote:
> On Wed, Jun 03, 2015 at 11:53:37AM +0800, Eryu Guan wrote:
> > On Tue, Jun 02, 2015 at 07:35:03PM -0700, Omar Sandoval wrote:
> > > Add a regression test for a problem where attempting to delete the
> > > default subvolume would fail (as expected), but not until after all
> > > submounts under the subvolume were unmounted.
> > 
> > I think the subject can be more specific than "btrfs: default subvolume
> > deletion test", because btrfs/009 test the deletion of default subvol
> > too, but this test tests more.
> 
> Agreed.
> 
> > > Signed-off-by: Omar Sandoval <osandov@osandov.com>
> > > ---
> > >  tests/btrfs/089     | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> > >  tests/btrfs/089.out | 10 +++++++
> > >  tests/btrfs/group   |  1 +
> > >  3 files changed, 93 insertions(+)
> > >  create mode 100755 tests/btrfs/089
> > >  create mode 100644 tests/btrfs/089.out
> > > 
> > > diff --git a/tests/btrfs/089 b/tests/btrfs/089
> > > new file mode 100755
> > > index 000000000000..af28d996d5c6
> > > --- /dev/null
> > > +++ b/tests/btrfs/089
> > > @@ -0,0 +1,82 @@
> > > +#! /bin/bash
> > > +# FS QA Test 089
> > > +#
> > > +# Test deleting the default subvolume, making sure that it fails and that
> > > +# submounts under it are not unmounted prematurely. This is a regression test
> > > +# for Linux commit "Btrfs: don't invalidate root dentry when subvolume deletion
> > > +# fails".
> > > +#
> > > +#-----------------------------------------------------------------------
> > > +# Copyright (c) 2015 YOUR NAME HERE.  All Rights Reserved.
> > 
> > The copyright should be fixed.
> 
> Whoops, not sure how I missed that.
> 
> > > +#
> > > +# 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/filter.btrfs
> > > +
> > > +# real QA test starts here
> > > +
> > > +# Modify as appropriate.
> > > +_need_to_be_root
> > > +_supported_fs btrfs
> > > +_supported_os Linux
> > > +_require_scratch
> > > +
> > > +rm -f $seqres.full
> > > +
> > > +_scratch_mkfs >>$seqres.full 2>&1
> > > +_scratch_mount
> > > +
> > > +# Create a new subvolume and make it the default subvolume.
> > > +$BTRFS_UTIL_PROG subvolume create "$SCRATCH_MNT/testvol" | _filter_scratch
> > > +testvol_id=$($BTRFS_UTIL_PROG subvolume list "$SCRATCH_MNT/testvol" | awk '{print $2}')
> > 
> > I found there's a helper to get subvol id, see _btrfs_get_subvolid in
> > common/rc
> 
> Okay, I'll fix that.
> 
> > > +$BTRFS_UTIL_PROG subvolume set-default "$testvol_id" "$SCRATCH_MNT"
> > > +
> > > +# Bind-mount a directory under the default subvolume.
> > > +mkdir "$SCRATCH_MNT/testvol/testdir"
> > > +touch "$SCRATCH_MNT/testvol/testdir/testfile"
> > > +mkdir "$SCRATCH_MNT/testvol/mnt"
> > > +mount --bind "$SCRATCH_MNT/testvol/testdir" "$SCRATCH_MNT/testvol/mnt"
> > > +
> > > +# Now attempt to delete the default subvolume, which should fail.
> > > +$BTRFS_UTIL_PROG subvolume delete "$SCRATCH_MNT/testvol" 2>&1 | _filter_btrfs_subvol_delete
> > > +
> > > +# Make sure that the subvolume and bind mount survived.
> > > +cd "$SCRATCH_MNT"
> > > +find | sort
> > > +
> > > +cd "$here"
> > > +_scratch_unmount
> > 
> > The cd and _scratch_unmount are not necessary here, _require_scratch
> > deals with the umount.
> 
> Ah, yes, I can definitely get rid of the _scratch_unmount, but the cd
> $here was there because otherwise the filesystem wouldn't unmount and
> fsck would error out. Instead of cd-ing to SCRATCH_MNT, I can replace
> find with find | _filter_scratch and update the test output accordingly.

Oops, that was a big fat lie. The unmount was failing because the bind
mount was still alive.

> > Thanks,
> > Eryu
> 
> Thanks for reviewing! I'll send out v2.
> 
> > > +
> > > +status=0
> > > +exit
> > > diff --git a/tests/btrfs/089.out b/tests/btrfs/089.out
> > > new file mode 100644
> > > index 000000000000..eb9c5112e12e
> > > --- /dev/null
> > > +++ b/tests/btrfs/089.out
> > > @@ -0,0 +1,10 @@
> > > +qa output created by 089
> > > +create subvolume 'scratch_mnt/testvol'
> > > +error: cannot delete 'scratch_mnt/testvol' - operation not permitted
> > > +delete subvolume 'scratch_mnt/testvol'
> > > +.
> > > +./testvol
> > > +./testvol/mnt
> > > +./testvol/mnt/testfile
> > > +./testvol/testdir
> > > +./testvol/testdir/testfile
> > > diff --git a/tests/btrfs/group b/tests/btrfs/group
> > > index ffe18bff0d21..616d060758c1 100644
> > > --- a/tests/btrfs/group
> > > +++ b/tests/btrfs/group
> > > @@ -91,6 +91,7 @@
> > >  086 auto quick clone
> > >  087 auto quick send
> > >  088 auto quick metadata
> > > +089 auto quick subvol
> > >  090 auto quick metadata
> > >  091 auto quick qgroup
> > >  092 auto quick send
> > > -- 
> > > 2.4.2
> > > 
> > > --
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> 
> -- 
> Omar

-- 
Omar