overlay: add test for lowerdir mount option parsing

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>
Reviewed-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>

2 files changed, 78 insertions, 0 deletions

diff --git a/tests/overlay/083 b/tests/overlay/083
new file mode 100755
index 0000000000..df82d1fd42
--- /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 0000000000..0beba30978
--- /dev/null
+++ b/tests/overlay/083.out
@@ -0,0 +1,2 @@
+QA output created by 083
+Silence is golden