#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2023 CTERA Networks. All Rights Reserved.
#
# FSQA Test No. 081
#
# Test persistent (and optionally unique) overlayfs fsid
# with mount options uuid=null/auto/on introduced in kernel v6.6
#
. ./common/preamble
_begin_fstest auto quick

# Import common functions.
. ./common/filter
. ./common/attr

# real QA test starts here
_supported_fs overlay

_scratch_mkfs >>$seqres.full 2>&1

# Create overlay layer with pre-packaged merge dir
upperdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
workdir=$OVL_BASE_SCRATCH_MNT/$OVL_WORK
lowerdir=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER
mkdir -p $upperdir/test_dir
mkdir -p $lowerdir/test_dir
test_dir=$SCRATCH_MNT/test_dir/

# Record base fs fsid
upper_fsid=$(stat -f -c '%i' $upperdir)
lower_fsid=$(stat -f -c '%i' $lowerdir)

# Sanity tests
[[ -n "$upper_fsid" ]] || \
	echo "invalid upper fs fsid"
[[ "$lower_fsid" == "$upper_fsid" ]] || \
	echo "lower fs and upper fs fsid differ"

# Test legacy behavior - ovl fsid inherited from upper fs
_overlay_scratch_mount_dirs $lowerdir $upperdir $workdir -o uuid=null 2>/dev/null || \
	_notrun "Overlayfs does not support unique fsid feature"

# Lookup of test_dir marks upper root as "impure", so following (uuid=auto) mounts
# will NOT behave as first time mount of a new overlayfs
ovl_fsid=$(stat -f -c '%i' $test_dir)
[[ "$ovl_fsid" == "$upper_fsid" ]] || \
	echo "Overlayfs (uuid=null) and upper fs fsid differ"

# Keep base fs mounted in case it has a volatile fsid (e.g. tmpfs)
$UMOUNT_PROG $SCRATCH_MNT

# Test legacy behavior is preserved by default for existing "impure" overlayfs
_scratch_mount

ovl_fsid=$(stat -f -c '%i' $test_dir)
[[ "$ovl_fsid" == "$upper_fsid" ]] || \
	echo "Overlayfs (after uuid=null) and upper fs fsid differ"

$UMOUNT_PROG $SCRATCH_MNT

# Test unique fsid on explicit opt-in for existing "impure" overlayfs
_scratch_mount -o uuid=on

ovl_fsid=$(stat -f -c '%i' $test_dir)
ovl_unique_fsid=$ovl_fsid
[[ "$ovl_fsid" != "$upper_fsid" ]] || \
	echo "Overlayfs (uuid=on) and upper fs fsid are the same"

$UMOUNT_PROG $SCRATCH_MNT

# Test unique fsid is persistent by default after it was created
_scratch_mount

ovl_fsid=$(stat -f -c '%i' $test_dir)
[[ "$ovl_fsid" == "$ovl_unique_fsid" ]] || \
	echo "Overlayfs (after uuid=on) unique fsid is not persistent"

$UMOUNT_PROG $SCRATCH_MNT

# Test ignore existing persistent fsid on explicit opt-out
_scratch_mount -o uuid=null

ovl_fsid=$(stat -f -c '%i' $test_dir)
[[ "$ovl_fsid" == "$upper_fsid" ]] || \
	echo "Overlayfs (uuid=null) and upper fs fsid differ"

$UMOUNT_PROG $SCRATCH_MNT

# Test fallback to uuid=null with non-upper ovelray
_overlay_scratch_mount_dirs "$upperdir:$lowerdir" "-" "-" -o ro,uuid=on

ovl_fsid=$(stat -f -c '%i' $test_dir)
[[ "$ovl_fsid" == "$lower_fsid" ]] || \
	echo "Overlayfs (no upper) and lower fs fsid differ"

# Re-create fresh overlay layers, so following (uuid=auto) mounts
# will behave as first time mount of a new overlayfs
_scratch_unmount
_scratch_mkfs >>$seqres.full 2>&1
mkdir -p $upperdir/test_dir
mkdir -p $lowerdir/test_dir

# Record new base fs fsid
upper_fsid=$(stat -f -c '%i' $upperdir)

# Test unique fsid by default for first time mount of new overlayfs
_scratch_mount

ovl_fsid=$(stat -f -c '%i' $test_dir)
ovl_unique_fsid=$ovl_fsid
[[ "$ovl_fsid" != "$upper_fsid" ]] || \
	echo "Overlayfs (new) and upper fs fsid are the same"

$UMOUNT_PROG $SCRATCH_MNT

# Test unique fsid is persistent by default after it was created
_scratch_mount -o uuid=on

ovl_fsid=$(stat -f -c '%i' $test_dir)
[[ "$ovl_fsid" == "$ovl_unique_fsid" ]] || \
	echo "Overlayfs (uuid=on) unique fsid is not persistent"

$UMOUNT_PROG $SCRATCH_MNT

echo "Silence is golden"
status=0
exit