diff mbox series

[v3] overlay: add test for lowerdir mount option parsing

Message ID 20231023163259.2949803-1-amir73il@gmail.com (mailing list archive)
State New, archived
Headers show
Series [v3] overlay: add test for lowerdir mount option parsing | expand

Commit Message

Amir Goldstein Oct. 23, 2023, 4:32 p.m. UTC 
Check parsing and display of spaces and escaped colons and commans in
lowerdir mount option.

This is a regression test for two bugs introduced in v6.5 with the
conversion to new mount api.

There is another regression of new mount api related to libmount parsing
of escaped commas, but this needs a fix in libmount - this test only
verifies the fixes in the kernel, so it uses LIBMOUNT_FORCE_MOUNT2=always
to force mount(2) and kernel pasring of the comma separated options list.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---

Changes since v2:
- Fix test for when index feature is enabled

Changes since v1:
- Fix test for libmount >= 2.39

 tests/overlay/083     | 76 +++++++++++++++++++++++++++++++++++++++++++
 tests/overlay/083.out |  2 ++
 2 files changed, 78 insertions(+)
 create mode 100755 tests/overlay/083
 create mode 100644 tests/overlay/083.out

Comments

Zorro Lang Oct. 24, 2023, 5:24 a.m. UTC | #1 
On Mon, Oct 23, 2023 at 07:32:59PM +0300, Amir Goldstein wrote:
> Check parsing and display of spaces and escaped colons and commans in
> lowerdir mount option.
> 
> This is a regression test for two bugs introduced in v6.5 with the
> conversion to new mount api.
> 
> There is another regression of new mount api related to libmount parsing
> of escaped commas, but this needs a fix in libmount - this test only
> verifies the fixes in the kernel, so it uses LIBMOUNT_FORCE_MOUNT2=always
> to force mount(2) and kernel pasring of the comma separated options list.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
> 
> Changes since v2:
> - Fix test for when index feature is enabled
> 
> Changes since v1:
> - Fix test for libmount >= 2.39
> 
>  tests/overlay/083     | 76 +++++++++++++++++++++++++++++++++++++++++++
>  tests/overlay/083.out |  2 ++
>  2 files changed, 78 insertions(+)
>  create mode 100755 tests/overlay/083
>  create mode 100644 tests/overlay/083.out
> 
> diff --git a/tests/overlay/083 b/tests/overlay/083
> new file mode 100755
> index 00000000..df82d1fd
> --- /dev/null
> +++ b/tests/overlay/083
> @@ -0,0 +1,76 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (C) 2023 CTERA Networks. All Rights Reserved.
> +#
> +# FS QA Test 083
> +#
> +# Test regressions in parsing and display of special chars in mount options.
> +#
> +# The following kernel commits from v6.5 introduced regressions:
> +#  b36a5780cb44 ("ovl: modify layer parameter parsing")
> +#  1784fbc2ed9c ("ovl: port to new mount api")
> +#
> +
> +. ./common/preamble
> +_begin_fstest auto quick mount
> +
> +# Import common functions.
> +. ./common/filter
> +
> +# real QA test starts here
> +_supported_fs overlay
> +_fixed_by_kernel_commit 32db51070850 \
> +	"ovl: fix regression in showing lowerdir mount option"
> +_fixed_by_kernel_commit c34706acf40b \
> +	"ovl: fix regression in parsing of mount options with escaped comma"
> +
> +# _overlay_check_* helpers do not handle special chars well
> +_require_scratch_nocheck
> +
> +# Remove all files from previous tests
> +_scratch_mkfs
> +
> +# Create lowerdirs with special characters
> +lowerdir_spaces="$OVL_BASE_SCRATCH_MNT/lower1 with  spaces"
> +lowerdir_colons="$OVL_BASE_SCRATCH_MNT/lower2:with::colons"
> +lowerdir_commas="$OVL_BASE_SCRATCH_MNT/lower3,with,,commas"
> +lowerdir_colons_esc="$OVL_BASE_SCRATCH_MNT/lower2\:with\:\:colons"
> +lowerdir_commas_esc="$OVL_BASE_SCRATCH_MNT/lower3\,with\,\,commas"
> +upperdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
> +workdir=$OVL_BASE_SCRATCH_MNT/$OVL_WORK
> +mkdir -p "$lowerdir_spaces" "$lowerdir_colons" "$lowerdir_commas"
> +
> +# _overlay_mount_* helpers do not handle special chars well, so execute mount directly.
> +# if escaped colons are not parsed correctly, mount will fail.
> +$MOUNT_PROG -t overlay ovl_esc_test $SCRATCH_MNT \
> +	-o"upperdir=$upperdir,workdir=$workdir" \
> +	-o"lowerdir=$lowerdir_colons_esc:$lowerdir_spaces" \
> +	2>&1 | tee -a $seqres.full
> +
> +# if spaces are not escaped when showing mount options,
> +# mount command will not show the word 'spaces' after the spaces
> +$MOUNT_PROG -t overlay | grep ovl_esc_test  | tee -a $seqres.full | grep -v spaces && \
> +	echo "ERROR: escaped spaces truncated from lowerdir mount option"
> +
> +# Re-create the upper/work dirs to mount them with a different lower
> +# This is required in case index feature is enabled
> +$UMOUNT_PROG $SCRATCH_MNT
> +rm -rf "$upperdir" "$workdir"
> +mkdir -p "$upperdir" "$workdir"
> +
> +# Kernel commit c34706acf40b fixes parsing of mount options with escaped comma
> +# when the mount options string is provided via data argument to mount(2) syscall.
> +# With libmount >= 2.39, libmount itself will try to split the comma separated
> +# options list provided to mount(8) commnad line and call fsconfig(2) for each
> +# mount option seperately.  Since libmount does not obay to overlayfs escaped
> +# commas format, it will call fsconfig(2) with the wrong path (i.e. ".../lower3")
> +# and this test will fail, but the failure would indicate a libmount issue, not
> +# a kernel issue.  Therefore, force libmount to use mount(2) syscall, so we only
> +# test the kernel fix.
> +LIBMOUNT_FORCE_MOUNT2=always $MOUNT_PROG -t overlay $OVL_BASE_SCRATCH_DEV $SCRATCH_MNT \
> +	-o"upperdir=$upperdir,workdir=$workdir,lowerdir=$lowerdir_commas_esc" 2>> $seqres.full || \
> +	echo "ERROR: incorrect parsing of escaped comma in lowerdir mount option"

This version looks good to me. I just hope we can remove the "LIBMOUNT_FORCE_MOUNT2=always"
after that issue get fixed, to let this case cover new mount API test too.

Reviewed-by: Zorro Lang <zlang@redhat.com>

Thanks,
Zorro

> +
> +echo "Silence is golden"
> +status=0
> +exit
> diff --git a/tests/overlay/083.out b/tests/overlay/083.out
> new file mode 100644
> index 00000000..0beba309
> --- /dev/null
> +++ b/tests/overlay/083.out
> @@ -0,0 +1,2 @@
> +QA output created by 083
> +Silence is golden
> -- 
> 2.34.1
>
Amir Goldstein Oct. 24, 2023, 6:48 a.m. UTC | #2 
On Tue, Oct 24, 2023 at 8:24 AM Zorro Lang <zlang@redhat.com> wrote:
>
> On Mon, Oct 23, 2023 at 07:32:59PM +0300, Amir Goldstein wrote:
> > Check parsing and display of spaces and escaped colons and commans in
> > lowerdir mount option.
> >
> > This is a regression test for two bugs introduced in v6.5 with the
> > conversion to new mount api.
> >
> > There is another regression of new mount api related to libmount parsing
> > of escaped commas, but this needs a fix in libmount - this test only
> > verifies the fixes in the kernel, so it uses LIBMOUNT_FORCE_MOUNT2=always
> > to force mount(2) and kernel pasring of the comma separated options list.
> >
> > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > ---
> >
> > Changes since v2:
> > - Fix test for when index feature is enabled
> >
> > Changes since v1:
> > - Fix test for libmount >= 2.39
> >
> >  tests/overlay/083     | 76 +++++++++++++++++++++++++++++++++++++++++++
> >  tests/overlay/083.out |  2 ++
> >  2 files changed, 78 insertions(+)
> >  create mode 100755 tests/overlay/083
> >  create mode 100644 tests/overlay/083.out
> >
> > diff --git a/tests/overlay/083 b/tests/overlay/083
> > new file mode 100755
> > index 00000000..df82d1fd
> > --- /dev/null
> > +++ b/tests/overlay/083
> > @@ -0,0 +1,76 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (C) 2023 CTERA Networks. All Rights Reserved.
> > +#
> > +# FS QA Test 083
> > +#
> > +# Test regressions in parsing and display of special chars in mount options.
> > +#
> > +# The following kernel commits from v6.5 introduced regressions:
> > +#  b36a5780cb44 ("ovl: modify layer parameter parsing")
> > +#  1784fbc2ed9c ("ovl: port to new mount api")
> > +#
> > +
> > +. ./common/preamble
> > +_begin_fstest auto quick mount
> > +
> > +# Import common functions.
> > +. ./common/filter
> > +
> > +# real QA test starts here
> > +_supported_fs overlay
> > +_fixed_by_kernel_commit 32db51070850 \
> > +     "ovl: fix regression in showing lowerdir mount option"
> > +_fixed_by_kernel_commit c34706acf40b \
> > +     "ovl: fix regression in parsing of mount options with escaped comma"
> > +
> > +# _overlay_check_* helpers do not handle special chars well
> > +_require_scratch_nocheck
> > +
> > +# Remove all files from previous tests
> > +_scratch_mkfs
> > +
> > +# Create lowerdirs with special characters
> > +lowerdir_spaces="$OVL_BASE_SCRATCH_MNT/lower1 with  spaces"
> > +lowerdir_colons="$OVL_BASE_SCRATCH_MNT/lower2:with::colons"
> > +lowerdir_commas="$OVL_BASE_SCRATCH_MNT/lower3,with,,commas"
> > +lowerdir_colons_esc="$OVL_BASE_SCRATCH_MNT/lower2\:with\:\:colons"
> > +lowerdir_commas_esc="$OVL_BASE_SCRATCH_MNT/lower3\,with\,\,commas"
> > +upperdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
> > +workdir=$OVL_BASE_SCRATCH_MNT/$OVL_WORK
> > +mkdir -p "$lowerdir_spaces" "$lowerdir_colons" "$lowerdir_commas"
> > +
> > +# _overlay_mount_* helpers do not handle special chars well, so execute mount directly.
> > +# if escaped colons are not parsed correctly, mount will fail.
> > +$MOUNT_PROG -t overlay ovl_esc_test $SCRATCH_MNT \
> > +     -o"upperdir=$upperdir,workdir=$workdir" \
> > +     -o"lowerdir=$lowerdir_colons_esc:$lowerdir_spaces" \
> > +     2>&1 | tee -a $seqres.full
> > +
> > +# if spaces are not escaped when showing mount options,
> > +# mount command will not show the word 'spaces' after the spaces
> > +$MOUNT_PROG -t overlay | grep ovl_esc_test  | tee -a $seqres.full | grep -v spaces && \
> > +     echo "ERROR: escaped spaces truncated from lowerdir mount option"
> > +
> > +# Re-create the upper/work dirs to mount them with a different lower
> > +# This is required in case index feature is enabled
> > +$UMOUNT_PROG $SCRATCH_MNT
> > +rm -rf "$upperdir" "$workdir"
> > +mkdir -p "$upperdir" "$workdir"
> > +
> > +# Kernel commit c34706acf40b fixes parsing of mount options with escaped comma
> > +# when the mount options string is provided via data argument to mount(2) syscall.
> > +# With libmount >= 2.39, libmount itself will try to split the comma separated
> > +# options list provided to mount(8) commnad line and call fsconfig(2) for each
> > +# mount option seperately.  Since libmount does not obay to overlayfs escaped
> > +# commas format, it will call fsconfig(2) with the wrong path (i.e. ".../lower3")
> > +# and this test will fail, but the failure would indicate a libmount issue, not
> > +# a kernel issue.  Therefore, force libmount to use mount(2) syscall, so we only
> > +# test the kernel fix.
> > +LIBMOUNT_FORCE_MOUNT2=always $MOUNT_PROG -t overlay $OVL_BASE_SCRATCH_DEV $SCRATCH_MNT \
> > +     -o"upperdir=$upperdir,workdir=$workdir,lowerdir=$lowerdir_commas_esc" 2>> $seqres.full || \
> > +     echo "ERROR: incorrect parsing of escaped comma in lowerdir mount option"
>
> This version looks good to me. I just hope we can remove the "LIBMOUNT_FORCE_MOUNT2=always"
> after that issue get fixed, to let this case cover new mount API test too.
>

TBH, I am not really sure the best approach here would be.
Let's say that the issue gets fixed in libmount 2.40.
Would we then remove "LIBMOUNT_FORCE_MOUNT2=always"
and add a hint:

_fixed_in_version libmount 2.40

Do you think that would be the appropriate thing to do for fstests?

I am asking because so far fstests was used to track regressions
in kernel and in various fs progs, e.g.:
_fixed_by_git_commit btrfs-progs ...
_fixed_by_git_commit xfsprogs ...
_fixed_by_git_commit xfsdump ...

Where developers of said fs progs often build their own binaries.

An alternative would be to extend _require_command to take
an optional min_ver argument and try to figure out the version
from running $command -V (best effort).
I am not going to cheer for this approach...

Anyway, we plan to add new overlayfs mount options that
are only supported with FSCONFIG_SET_PATH and libmount 2.39
does not support this yet, so are probably going to need to use
a helper program in src to test the new mount API on overlayfs anyway.

Thanks,
Amir.
Zorro Lang Oct. 24, 2023, 8:36 a.m. UTC | #3 
On Tue, Oct 24, 2023 at 09:48:42AM +0300, Amir Goldstein wrote:
> On Tue, Oct 24, 2023 at 8:24 AM Zorro Lang <zlang@redhat.com> wrote:
> >
> > On Mon, Oct 23, 2023 at 07:32:59PM +0300, Amir Goldstein wrote:
> > > Check parsing and display of spaces and escaped colons and commans in
> > > lowerdir mount option.
> > >
> > > This is a regression test for two bugs introduced in v6.5 with the
> > > conversion to new mount api.
> > >
> > > There is another regression of new mount api related to libmount parsing
> > > of escaped commas, but this needs a fix in libmount - this test only
> > > verifies the fixes in the kernel, so it uses LIBMOUNT_FORCE_MOUNT2=always
> > > to force mount(2) and kernel pasring of the comma separated options list.
> > >
> > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > > ---
> > >
> > > Changes since v2:
> > > - Fix test for when index feature is enabled
> > >
> > > Changes since v1:
> > > - Fix test for libmount >= 2.39
> > >
> > >  tests/overlay/083     | 76 +++++++++++++++++++++++++++++++++++++++++++
> > >  tests/overlay/083.out |  2 ++
> > >  2 files changed, 78 insertions(+)
> > >  create mode 100755 tests/overlay/083
> > >  create mode 100644 tests/overlay/083.out
> > >
> > > diff --git a/tests/overlay/083 b/tests/overlay/083
> > > new file mode 100755
> > > index 00000000..df82d1fd
> > > --- /dev/null
> > > +++ b/tests/overlay/083
> > > @@ -0,0 +1,76 @@
> > > +#! /bin/bash
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +# Copyright (C) 2023 CTERA Networks. All Rights Reserved.
> > > +#
> > > +# FS QA Test 083
> > > +#
> > > +# Test regressions in parsing and display of special chars in mount options.
> > > +#
> > > +# The following kernel commits from v6.5 introduced regressions:
> > > +#  b36a5780cb44 ("ovl: modify layer parameter parsing")
> > > +#  1784fbc2ed9c ("ovl: port to new mount api")
> > > +#
> > > +
> > > +. ./common/preamble
> > > +_begin_fstest auto quick mount
> > > +
> > > +# Import common functions.
> > > +. ./common/filter
> > > +
> > > +# real QA test starts here
> > > +_supported_fs overlay
> > > +_fixed_by_kernel_commit 32db51070850 \
> > > +     "ovl: fix regression in showing lowerdir mount option"
> > > +_fixed_by_kernel_commit c34706acf40b \
> > > +     "ovl: fix regression in parsing of mount options with escaped comma"
> > > +
> > > +# _overlay_check_* helpers do not handle special chars well
> > > +_require_scratch_nocheck
> > > +
> > > +# Remove all files from previous tests
> > > +_scratch_mkfs
> > > +
> > > +# Create lowerdirs with special characters
> > > +lowerdir_spaces="$OVL_BASE_SCRATCH_MNT/lower1 with  spaces"
> > > +lowerdir_colons="$OVL_BASE_SCRATCH_MNT/lower2:with::colons"
> > > +lowerdir_commas="$OVL_BASE_SCRATCH_MNT/lower3,with,,commas"
> > > +lowerdir_colons_esc="$OVL_BASE_SCRATCH_MNT/lower2\:with\:\:colons"
> > > +lowerdir_commas_esc="$OVL_BASE_SCRATCH_MNT/lower3\,with\,\,commas"
> > > +upperdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
> > > +workdir=$OVL_BASE_SCRATCH_MNT/$OVL_WORK
> > > +mkdir -p "$lowerdir_spaces" "$lowerdir_colons" "$lowerdir_commas"
> > > +
> > > +# _overlay_mount_* helpers do not handle special chars well, so execute mount directly.
> > > +# if escaped colons are not parsed correctly, mount will fail.
> > > +$MOUNT_PROG -t overlay ovl_esc_test $SCRATCH_MNT \
> > > +     -o"upperdir=$upperdir,workdir=$workdir" \
> > > +     -o"lowerdir=$lowerdir_colons_esc:$lowerdir_spaces" \
> > > +     2>&1 | tee -a $seqres.full
> > > +
> > > +# if spaces are not escaped when showing mount options,
> > > +# mount command will not show the word 'spaces' after the spaces
> > > +$MOUNT_PROG -t overlay | grep ovl_esc_test  | tee -a $seqres.full | grep -v spaces && \
> > > +     echo "ERROR: escaped spaces truncated from lowerdir mount option"
> > > +
> > > +# Re-create the upper/work dirs to mount them with a different lower
> > > +# This is required in case index feature is enabled
> > > +$UMOUNT_PROG $SCRATCH_MNT
> > > +rm -rf "$upperdir" "$workdir"
> > > +mkdir -p "$upperdir" "$workdir"
> > > +
> > > +# Kernel commit c34706acf40b fixes parsing of mount options with escaped comma
> > > +# when the mount options string is provided via data argument to mount(2) syscall.
> > > +# With libmount >= 2.39, libmount itself will try to split the comma separated
> > > +# options list provided to mount(8) commnad line and call fsconfig(2) for each
> > > +# mount option seperately.  Since libmount does not obay to overlayfs escaped
> > > +# commas format, it will call fsconfig(2) with the wrong path (i.e. ".../lower3")
> > > +# and this test will fail, but the failure would indicate a libmount issue, not
> > > +# a kernel issue.  Therefore, force libmount to use mount(2) syscall, so we only
> > > +# test the kernel fix.
> > > +LIBMOUNT_FORCE_MOUNT2=always $MOUNT_PROG -t overlay $OVL_BASE_SCRATCH_DEV $SCRATCH_MNT \
> > > +     -o"upperdir=$upperdir,workdir=$workdir,lowerdir=$lowerdir_commas_esc" 2>> $seqres.full || \
> > > +     echo "ERROR: incorrect parsing of escaped comma in lowerdir mount option"
> >
> > This version looks good to me. I just hope we can remove the "LIBMOUNT_FORCE_MOUNT2=always"
> > after that issue get fixed, to let this case cover new mount API test too.
> >
> 
> TBH, I am not really sure the best approach here would be.
> Let's say that the issue gets fixed in libmount 2.40.
> Would we then remove "LIBMOUNT_FORCE_MOUNT2=always"
> and add a hint:
> 
> _fixed_in_version libmount 2.40

Sure, that's good to me. If there's a git commit ($id $subject), I think
that would be better than the version number, e.g.

  # A known issue of util-linux/libmount ....
  _fixed_by_git_commit util-linux xxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxxxx

Due to ...

> 
> Do you think that would be the appropriate thing to do for fstests?
> 
> I am asking because so far fstests was used to track regressions
> in kernel and in various fs progs, e.g.:
> _fixed_by_git_commit btrfs-progs ...
> _fixed_by_git_commit xfsprogs ...
> _fixed_by_git_commit xfsdump ...
> 
> Where developers of said fs progs often build their own binaries.

... as you say, downstream progs might have their own backport and build.

Thanks,
Zorro

> 
> An alternative would be to extend _require_command to take
> an optional min_ver argument and try to figure out the version
> from running $command -V (best effort).
> I am not going to cheer for this approach...
> 
> Anyway, we plan to add new overlayfs mount options that
> are only supported with FSCONFIG_SET_PATH and libmount 2.39
> does not support this yet, so are probably going to need to use
> a helper program in src to test the new mount API on overlayfs anyway.
> 
> Thanks,
> Amir.
>
diff mbox series

Patch

diff --git a/tests/overlay/083 b/tests/overlay/083
new file mode 100755
index 00000000..df82d1fd
--- /dev/null
+++ b/tests/overlay/083
@@ -0,0 +1,76 @@ 
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2023 CTERA Networks. All Rights Reserved.
+#
+# FS QA Test 083
+#
+# Test regressions in parsing and display of special chars in mount options.
+#
+# The following kernel commits from v6.5 introduced regressions:
+#  b36a5780cb44 ("ovl: modify layer parameter parsing")
+#  1784fbc2ed9c ("ovl: port to new mount api")
+#
+
+. ./common/preamble
+_begin_fstest auto quick mount
+
+# Import common functions.
+. ./common/filter
+
+# real QA test starts here
+_supported_fs overlay
+_fixed_by_kernel_commit 32db51070850 \
+	"ovl: fix regression in showing lowerdir mount option"
+_fixed_by_kernel_commit c34706acf40b \
+	"ovl: fix regression in parsing of mount options with escaped comma"
+
+# _overlay_check_* helpers do not handle special chars well
+_require_scratch_nocheck
+
+# Remove all files from previous tests
+_scratch_mkfs
+
+# Create lowerdirs with special characters
+lowerdir_spaces="$OVL_BASE_SCRATCH_MNT/lower1 with  spaces"
+lowerdir_colons="$OVL_BASE_SCRATCH_MNT/lower2:with::colons"
+lowerdir_commas="$OVL_BASE_SCRATCH_MNT/lower3,with,,commas"
+lowerdir_colons_esc="$OVL_BASE_SCRATCH_MNT/lower2\:with\:\:colons"
+lowerdir_commas_esc="$OVL_BASE_SCRATCH_MNT/lower3\,with\,\,commas"
+upperdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
+workdir=$OVL_BASE_SCRATCH_MNT/$OVL_WORK
+mkdir -p "$lowerdir_spaces" "$lowerdir_colons" "$lowerdir_commas"
+
+# _overlay_mount_* helpers do not handle special chars well, so execute mount directly.
+# if escaped colons are not parsed correctly, mount will fail.
+$MOUNT_PROG -t overlay ovl_esc_test $SCRATCH_MNT \
+	-o"upperdir=$upperdir,workdir=$workdir" \
+	-o"lowerdir=$lowerdir_colons_esc:$lowerdir_spaces" \
+	2>&1 | tee -a $seqres.full
+
+# if spaces are not escaped when showing mount options,
+# mount command will not show the word 'spaces' after the spaces
+$MOUNT_PROG -t overlay | grep ovl_esc_test  | tee -a $seqres.full | grep -v spaces && \
+	echo "ERROR: escaped spaces truncated from lowerdir mount option"
+
+# Re-create the upper/work dirs to mount them with a different lower
+# This is required in case index feature is enabled
+$UMOUNT_PROG $SCRATCH_MNT
+rm -rf "$upperdir" "$workdir"
+mkdir -p "$upperdir" "$workdir"
+
+# Kernel commit c34706acf40b fixes parsing of mount options with escaped comma
+# when the mount options string is provided via data argument to mount(2) syscall.
+# With libmount >= 2.39, libmount itself will try to split the comma separated
+# options list provided to mount(8) commnad line and call fsconfig(2) for each
+# mount option seperately.  Since libmount does not obay to overlayfs escaped
+# commas format, it will call fsconfig(2) with the wrong path (i.e. ".../lower3")
+# and this test will fail, but the failure would indicate a libmount issue, not
+# a kernel issue.  Therefore, force libmount to use mount(2) syscall, so we only
+# test the kernel fix.
+LIBMOUNT_FORCE_MOUNT2=always $MOUNT_PROG -t overlay $OVL_BASE_SCRATCH_DEV $SCRATCH_MNT \
+	-o"upperdir=$upperdir,workdir=$workdir,lowerdir=$lowerdir_commas_esc" 2>> $seqres.full || \
+	echo "ERROR: incorrect parsing of escaped comma in lowerdir mount option"
+
+echo "Silence is golden"
+status=0
+exit
diff --git a/tests/overlay/083.out b/tests/overlay/083.out
new file mode 100644
index 00000000..0beba309
--- /dev/null
+++ b/tests/overlay/083.out
@@ -0,0 +1,2 @@ 
+QA output created by 083
+Silence is golden