[PATCH v2 3/3] overlay: mount/unmount base fs before/after running tests

Amir Goldstein
2017-01-27T09:23:34Z

Optionally configure TEST/SCRATCH_BASE_DEV, for overlay base fs
to be mounted/unmounted before/after running tests. For example:

+export TEST_BASE_DEV=/dev/mapper/base-test
export TEST_BASE_MNT=/mnt/base/test
+export SCRATCH_BASE_DEV=/dev/mapper/base-scratch
export SCRATCH_BASE_MNT=/mnt/base/scratch
export TEST_DIR=/mnt/test
export SCRATCH_MNT=/mnt/scratch
export FSTYP=overlay

With this change, the base fs is mounted before running tests,
unmounted after running tests and recycled on _test_cycle_mount
along with the overlay mounts.
This helps catching overlayfs bugs related to leaking objects in
underlying (base) fs.

The standard way that overlay tests work is:
- _scratch_mkfs
- setup lower/upper dir files
- _scratch_mount (or custom overlay mount)
- (sometimes) _scratch_unmount/_scratch_mount recycle

To preserve expected tests behavior, the semantics are:
- _scratch_mkfs mounts the base fs, cleans the lower/upper dirs and
keeps base fs mounted.
- _scratch_mount mounts or recycles base fs and mounts overlay
- _scratch_unmount unmounts overlay and base fs

Tests that use _scratch_unmount to unmount a custom overlay mount
and expect to have access to overlay base dir, were converted to use
explicit umount $SCRATCH_MNT instead.
---
common/config | 6 +++++-
common/rc | 42 ++++++++++++++++++++++++++++++++++++++++++
tests/overlay/003 | 3 ++-
tests/overlay/004 | 3 ++-
tests/overlay/014 | 5 +++--
5 files changed, 54 insertions(+), 5 deletions(-)

diff --git a/common/config b/common/config
index db5721c..f431a8d 100644
--- a/common/config
+++ b/common/config
@@ -35,7 +35,9 @@
# RMT_TAPE_DEV - the remote tape device for the xfsdump tests
# RMT_IRIXTAPE_DEV- the IRIX remote tape device for the xfsdump tests
# RMT_TAPE_USER - remote user for tape device
+# TEST_BASE_DEV - device for base fs containing overlay test dirs
# TEST_BASE_MNT - mount point for base fs of overlay test dirs
+# SCRATCH_BASE_DEV- device for base fs containing overlay scratch dirs
# SCRATCH_BASE_MNT- mount point for base fs of overlay scratch dirs
#
# - These can be added to $HOST_CONFIG_DIR (witch default to ./config)
@@ -470,11 +472,12 @@ _config_overlay()
[ -z "$TEST_DEV" ] || export TEST_BASE_DIR="$TEST_DEV"
[ -z "$SCRATCH_DEV" ] || export SCRATCH_BASE_DIR="$SCRATCH_DEV"

- # 2. set SCRATCH/TEST_BASE_MNT to configure base fs.
+ # 2. set SCRATCH/TEST_BASE_DEV/MNT to configure base fs.
# SCRATCH/TEST_DEV are derived from SCRATCH/TEST_BASE_MNT
# and therein, overlay fs directories will be created.
[ -n "$TEST_BASE_MNT" ] || return

+ _check_device TEST_BASE_DEV optional $TEST_BASE_DEV
if [ ! -d "$TEST_BASE_MNT" ]; then
echo "common/config: Error: \$TEST_BASE_MNT ($TEST_BASE_MNT) is not a directory"
exit 1
@@ -486,6 +489,7 @@ _config_overlay()

[ -n "$SCRATCH_BASE_MNT" ] || return

+ _check_device SCRATCH_BASE_DEV optional $SCRATCH_BASE_DEV
if [ ! -d "$SCRATCH_BASE_MNT" ]; then
echo "common/config: Error: \$SCRATCH_BASE_MNT ($SCRATCH_BASE_MNT) is not a directory"
exit 1
diff --git a/common/rc b/common/rc
index f5ab869..5033ed4 100644
--- a/common/rc
+++ b/common/rc
@@ -320,24 +320,62 @@ _overlay_mount()
$SELINUX_MOUNT_OPTIONS $* $dir $mnt
}

+_overlay_test_base_mount()
+{
+ if [ -n "$TEST_BASE_DEV" -a -n "$TEST_BASE_MNT" ]; then
+ _mount $TEST_BASE_MOUNT_OPTIONS \
+ $SELINUX_MOUNT_OPTIONS \
+ $TEST_BASE_DEV $TEST_BASE_MNT
+ fi
+}
+
_overlay_test_mount()
{
+ _overlay_test_base_mount
_overlay_mount $TEST_BASE_DIR $TEST_DIR $*
}

+_overlay_scratch_base_mount()
+{
+ if [ -n "$SCRATCH_BASE_DEV" -a -n "$SCRATCH_BASE_MNT" ]; then
+ _mount $SCRATCH_BASE_MOUNT_OPTIONS \
+ $SELINUX_MOUNT_OPTIONS \
+ $SCRATCH_BASE_DEV $SCRATCH_BASE_MNT
+ fi
+}
+
+_overlay_scratch_base_unmount()
+{
+ if [ -n "$SCRATCH_BASE_DEV" -a -n "$SCRATCH_BASE_MNT" ]; then
+ $UMOUNT_PROG $SCRATCH_BASE_MNT
+ fi
+}
+
_overlay_scratch_mount()
{
+ # base fs may be mounted after overlay mkfs
+ _overlay_scratch_base_unmount 2>/dev/null
+ _overlay_scratch_base_mount
_overlay_mount $SCRATCH_BASE_DIR $SCRATCH_MNT $*
}

+_overlay_test_base_unmount()
+{
+ if [ -n "$TEST_BASE_DEV" -a -n "$TEST_BASE_MNT" ]; then
+ $UMOUNT_PROG $TEST_BASE_MNT
+ fi
+}
+
_overlay_test_unmount()
{
$UMOUNT_PROG $TEST_DIR
+ _overlay_test_base_unmount
}

_overlay_scratch_unmount()
{
$UMOUNT_PROG $SCRATCH_MNT
+ _overlay_scratch_base_unmount
}

_scratch_mount()
@@ -643,7 +681,11 @@ _scratch_cleanup_files()
overlay)
# Avoid rm -rf /* if we messed up
[ -n "$SCRATCH_BASE_DIR" ] || return
+ # overlay 'mkfs' needs to make sure base fs is mounted and clean
+ _overlay_scratch_base_unmount 2>/dev/null
+ _overlay_scratch_base_mount
rm -rf $SCRATCH_BASE_DIR/*
+ # leave base fs mouted so tests can setup lower dir
;;
*)
[ -n "$SCRATCH_MNT" ] || return
diff --git a/tests/overlay/003 b/tests/overlay/003
index bb59700..81aea85 100755
--- a/tests/overlay/003
+++ b/tests/overlay/003
@@ -89,7 +89,8 @@ rm -rf ${SCRATCH_MNT}/*
# nothing should be listed
ls ${SCRATCH_MNT}/

-_scratch_unmount
+# unmount overlayfs but not base fs
+$UMOUNT_PROG $SCRATCH_MNT

rm -rf $lowerdir
echo "Silence is golden"
diff --git a/tests/overlay/004 b/tests/overlay/004
index 6d78f9f..26ac547 100755
--- a/tests/overlay/004
+++ b/tests/overlay/004
@@ -85,7 +85,8 @@ _user_do "chmod g+t ${SCRATCH_MNT}/attr_file2 > /dev/null 2>&1"
_user_do "chmod u-X ${SCRATCH_MNT}/attr_file2 > /dev/null 2>&1"
stat -c %a ${SCRATCH_MNT}/attr_file2

-_scratch_unmount
+# unmount overlayfs but not base fs
+$UMOUNT_PROG $SCRATCH_MNT

# check mode bits of the file that has been copied up, and
# the file that should not have been copied up.
diff --git a/tests/overlay/014 b/tests/overlay/014
index 7426c31..6519432 100755
--- a/tests/overlay/014
+++ b/tests/overlay/014
@@ -73,7 +73,8 @@ mkdir -p $lowerdir1/testdir/d
_overlay_mount_dirs $lowerdir1 $lowerdir2 $workdir $SCRATCH_BASE_DIR $SCRATCH_MNT
rm -rf $SCRATCH_MNT/testdir
mkdir -p $SCRATCH_MNT/testdir/visibledir
-_scratch_unmount
+# unmount overlayfs but not base fs
+$UMOUNT_PROG $SCRATCH_MNT

# mount overlay again, with lowerdir1 and lowerdir2 as multiple lowerdirs,
# and create a new file in testdir, triggers copyup from lowerdir,
@@ -84,7 +85,7 @@ touch $SCRATCH_MNT/testdir/visiblefile

# umount and mount overlay again, buggy kernel treats the copied-up dir as
# opaque, visibledir is not seen in merged dir.
-_scratch_unmount
+$UMOUNT_PROG $SCRATCH_MNT
_overlay_mount_dirs "$lowerdir2:$lowerdir1" $upperdir $workdir \
$SCRATCH_BASE_DIR $SCRATCH_MNT
ls $SCRATCH_MNT/testdir
--
2.7.4