[PATCH] btrfs: test quota disable during quota rescan

[PATCH] btrfs: test quota disable during quota rescan

[Justin Maggard]

This test case tests if we are able to disable quotas on a filesystem
while a quota rescan is running.  Up to now (4.3) this would result
in a kernel NULL pointer dereference.

Fixed by patch (btrfs: qgroup: fix quota disable during rescan).

Signed-off-by: Justin Maggard <jmaggard@netgear.com>
---
 tests/btrfs/115     | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/btrfs/115.out |  2 ++
 tests/btrfs/group   |  1 +
 3 files changed, 65 insertions(+)
 create mode 100755 tests/btrfs/115
 create mode 100644 tests/btrfs/115.out

diff --git a/tests/btrfs/115 b/tests/btrfs/115
new file mode 100755
index 0000000..0d1cb3a
--- /dev/null
+++ b/tests/btrfs/115
@@ -0,0 +1,62 @@
+#! /bin/bash
+# FS QA Test No. btrfs/115
+#
+# btrfs quota scan/disable sanity test
+# Make sure that disabling quotas during a quota rescan doesn't crash
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2015 NETGEAR, 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 $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+_supported_fs btrfs
+_supported_os Linux
+_require_scratch
+
+_scratch_mkfs >>$seqres.full 2>&1
+_scratch_mount
+
+for i in `seq 0 1 450000`; do
+	echo -n > $SCRATCH_MNT/file.$i
+done
+echo 3 > /proc/sys/vm/drop_caches
+$BTRFS_UTIL_PROG quota enable $SCRATCH_MNT
+$BTRFS_UTIL_PROG quota disable $SCRATCH_MNT
+
+
+echo "Silence is golden"
+status=0
+exit
diff --git a/tests/btrfs/115.out b/tests/btrfs/115.out
new file mode 100644
index 0000000..d9dd136
--- /dev/null
+++ b/tests/btrfs/115.out
@@ -0,0 +1,2 @@
+QA output created by 115
+Silence is golden
diff --git a/tests/btrfs/group b/tests/btrfs/group
index 10ab26b..39b9aff 100644
--- a/tests/btrfs/group
+++ b/tests/btrfs/group
@@ -117,3 +117,4 @@
 112 auto quick clone
 113 auto quick compress clone
 114 auto qgroup
+115 auto qgroup
-- 
2.6.3

Re: [PATCH] btrfs: test quota disable during quota rescan

[Filipe Manana]

On Fri, Nov 6, 2015 at 6:40 PM, Justin Maggard <jmaggard10@gmail.com> wrote:
> This test case tests if we are able to disable quotas on a filesystem
> while a quota rescan is running.  Up to now (4.3) this would result
> in a kernel NULL pointer dereference.
>
> Fixed by patch (btrfs: qgroup: fix quota disable during rescan).
>
> Signed-off-by: Justin Maggard <jmaggard@netgear.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>

Looks good and it triggers the bug without the btrfs kernel fix.

A side note, and if you would like you could do as a separate patch
imho, is to speedup creating the files by using multiple
jobs/processes (as we do in generic/038 for example) - the test takes
150 seconds on a debug kernel here, about 130 seconds were spent
creating the files. Same observation applies to your previous test
case as well.

Thanks for making this test.

> ---
>  tests/btrfs/115     | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/115.out |  2 ++
>  tests/btrfs/group   |  1 +
>  3 files changed, 65 insertions(+)
>  create mode 100755 tests/btrfs/115
>  create mode 100644 tests/btrfs/115.out
>
> diff --git a/tests/btrfs/115 b/tests/btrfs/115
> new file mode 100755
> index 0000000..0d1cb3a
> --- /dev/null
> +++ b/tests/btrfs/115
> @@ -0,0 +1,62 @@
> +#! /bin/bash
> +# FS QA Test No. btrfs/115
> +#
> +# btrfs quota scan/disable sanity test
> +# Make sure that disabling quotas during a quota rescan doesn't crash
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2015 NETGEAR, 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 $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +
> +# real QA test starts here
> +_supported_fs btrfs
> +_supported_os Linux
> +_require_scratch
> +
> +_scratch_mkfs >>$seqres.full 2>&1
> +_scratch_mount
> +
> +for i in `seq 0 1 450000`; do
> +       echo -n > $SCRATCH_MNT/file.$i
> +done
> +echo 3 > /proc/sys/vm/drop_caches
> +$BTRFS_UTIL_PROG quota enable $SCRATCH_MNT
> +$BTRFS_UTIL_PROG quota disable $SCRATCH_MNT
> +
> +
> +echo "Silence is golden"
> +status=0
> +exit
> diff --git a/tests/btrfs/115.out b/tests/btrfs/115.out
> new file mode 100644
> index 0000000..d9dd136
> --- /dev/null
> +++ b/tests/btrfs/115.out
> @@ -0,0 +1,2 @@
> +QA output created by 115
> +Silence is golden
> diff --git a/tests/btrfs/group b/tests/btrfs/group
> index 10ab26b..39b9aff 100644
> --- a/tests/btrfs/group
> +++ b/tests/btrfs/group
> @@ -117,3 +117,4 @@
>  112 auto quick clone
>  113 auto quick compress clone
>  114 auto qgroup
> +115 auto qgroup
> --
> 2.6.3
>
> --
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-- 
Filipe David Manana,

"Reasonable men adapt themselves to the world.
 Unreasonable men adapt the world to themselves.
 That's why all progress depends on unreasonable men."

Re: [PATCH] btrfs: test quota disable during quota rescan

[Dave Chinner]

On Sat, Nov 07, 2015 at 03:08:01PM +0000, Filipe Manana wrote:
> On Fri, Nov 6, 2015 at 6:40 PM, Justin Maggard <jmaggard10@gmail.com> wrote:
> > This test case tests if we are able to disable quotas on a filesystem
> > while a quota rescan is running.  Up to now (4.3) this would result
> > in a kernel NULL pointer dereference.
> >
> > Fixed by patch (btrfs: qgroup: fix quota disable during rescan).
> >
> > Signed-off-by: Justin Maggard <jmaggard@netgear.com>
> Reviewed-by: Filipe Manana <fdmanana@suse.com>
> 
> Looks good and it triggers the bug without the btrfs kernel fix.
> 
> A side note, and if you would like you could do as a separate patch
> imho, is to speedup creating the files by using multiple
> jobs/processes (as we do in generic/038 for example) - the test takes
> 150 seconds on a debug kernel here, about 130 seconds were spent
> creating the files. Same observation applies to your previous test
> case as well.

Given how many people get such a basic operation "wrong", we need a
helper function for efficiently creating lots of empty files in a
filesystem.

Note that we already have _populate_fs(), but it's not very
efficient when it comes to empty files, nor does it use concurrency.
It seems to me that fixing this function and then using it
everywhere would be the best approach.  Perhaps even doing something
like making fs_mark use deep directory structures, and just calling
it instead to populate the filesystem?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com