#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2019 CTERA Networks. All Rights Reserved.
#
# FSQA Test No. 070
#
# This is a variant of overlay/017 to test constant st_ino numbers for
# nested overlay setup, where all layers of both overlays are on the
# same fs.
#
# This simple test demonstrates a known issue with overlayfs:
# - stat file A shows inode number X
# - modify A to trigger copy up
# - stat file A shows inode number Y != X
#
# Also test that d_ino of readdir entries and i_ino from /proc/locks are
# consistent with st_ino and that inode numbers persist after rename to
# new parent, drop caches and mount cycle.
#
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.*
	# Unmount the nested overlay mount
	$UMOUNT_PROG $mnt2 2>/dev/null
	[ -z "$loopdev" ] || _destroy_loop_device $loopdev
}

# get standard environment, filters and checks
. ./common/rc
. ./common/filter

# real QA test starts here
_supported_fs overlay
_supported_os Linux
_require_scratch_nocheck
_require_test_program "af_unix"
_require_test_program "t_dir_type"
_require_command "$FLOCK_PROG" "flock"
# We need to require all features together, because nfs_export cannot
# be enabled when index is disabled
_require_scratch_overlay_features index nfs_export redirect_dir
_require_loop

lower=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER
upper=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
work=$OVL_BASE_SCRATCH_MNT/$OVL_WORK
# Lower dir of nested overlay is the scratch overlay mount at SCRATCH_MNT
upper2=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER.2
work2=$OVL_BASE_SCRATCH_MNT/$OVL_WORK.2
mnt2=$OVL_BASE_SCRATCH_MNT/$OVL_MNT.2

lowerdir=$lower/lowertestdir
upperdir=$upper/uppertestdir
lowertestdir=$mnt2/lowertestdir
uppertestdir=$mnt2/uppertestdir

create_dirs()
{
	# Create the underlying overlay dirs
	_scratch_mkfs

	# Create the nested overlay upper dirs
	mkdir -p $upper2 $work2 $mnt2

	# Create a loop device for blkdev tests
	$XFS_IO_PROG -f -c "truncate 128k" $lower/img >> $seqres.full 2>&1
	loopdev=`_create_loop_device $lower/img`
}

# Mount a nested overlay with $SCRATCH_MNT as lower layer
mount_dirs()
{
	# Mount the underlying overlay with file handle support
	_scratch_mount -o "index=on,nfs_export=on"

	# Mount the nested overlay
	# Enable redirect_dir for renaming a merge directory.
	# Enabling xino in this test requires that base filesystem inode numbers will
	# not use bit 63 in inode number of the test files, because bit 63 is used by
	# overlayfs to indicate the layer. Let's just assume that this is true for all
	# tested filesystems and if we are wrong, the test may fail.
	_overlay_mount_dirs $SCRATCH_MNT $upper2 $work2 overlay2 $mnt2 \
		-o "redirect_dir=on,index=on,xino=on" || \
		_notrun "cannot mount nested overlay with xino=on option"
	_fs_options overlay2 | grep -q "xino=on" || \
		_notrun "cannot enable xino feature on nested overlay"
}

# Unmount the nested overlay mount and check underlying overlay layers
unmount_dirs()
{
	# unmount & check nested overlay
	$UMOUNT_PROG $mnt2
	_overlay_check_dirs $SCRATCH_MNT $upper2 $work2 \
		-o "redirect_dir=on,index=on,xino=on"

	# unmount & check underlying overlay
	$UMOUNT_PROG $SCRATCH_MNT
	_overlay_check_scratch_dirs $lower $upper $work \
		-o "index=on,nfs_export=on"
}

FILES="dir file symlink link chrdev blkdev fifo socket"

create_test_files()
{
	local dir=$1

	# Create our test files.
	mkdir -p $dir/dir
	touch $dir/file
	ln -s $dir/file $dir/symlink
	touch $dir/link
	ln $dir/link $dir/link2
	cp -a /dev/zero $dir/chrdev
	cp -a $loopdev $dir/blkdev
	mknod $dir/fifo p
	$here/src/af_unix $dir/socket
}

# Record inode numbers in format <ino> <basename>
record_inode_numbers()
{
	local dir=$1
	local outfile=$2

	echo "record_inode_numbers $outfile" >> $seqres.full

	for n in $FILES; do
		ls -id $dir/$n
	done | \
	while read ino file; do
		f=`basename $file`
		echo $ino $f | tee -a $seqres.full >> $outfile
		# /proc/locks exposes i_ino - compare it to st_ino. flock -n
		# doesn't follow symlink, blocks on fifo and fails on socket
		[[ $f =~ fifo|socket|symlink ]] || \
		$FLOCK_PROG -n $file cat /proc/locks | tee -a $seqres.full | grep -q ":$ino " || \
			echo "lock for $f not found by ino $ino ($outfile) - see $seqres.full"
	done
}

# Check inode numbers match recorder inode numbers
check_inode_numbers()
{
	local dir=$1
	local before=$2
	local after=$3

	record_inode_numbers $dir $after

	# Test constant stat(2) st_ino -
	# Compare before..after - expect silence
	# We use diff -u so out.bad will tell us which stage failed
	diff -u $before $after

	# Test constant readdir(3)/getdents(2) d_ino -
	# Expect to find file by inode number
	cat $before | while read ino f; do
		$here/src/t_dir_type $dir $ino | tee -a $seqres.full | grep -q $f || \
			echo "$f not found by ino $ino (from $before) - see $seqres.full"
	done
}

rm -f $seqres.full

create_dirs

create_test_files $lowerdir
create_test_files $upperdir

mount_dirs

# Record inode numbers in the lower overlay
record_inode_numbers $SCRATCH_MNT/lowertestdir $tmp.lower.lo
record_inode_numbers $SCRATCH_MNT/uppertestdir $tmp.lower.up

# Record inode numbers before copy up
record_inode_numbers $lowertestdir $tmp.before.lo
record_inode_numbers $uppertestdir $tmp.before.up

# Copy up all files
for f in $FILES; do
	# chown -h modifies all those file types
	chown -h 100 $lowertestdir/$f
	chown -h 100 $uppertestdir/$f
done

# Compare inode numbers before/after copy up
check_inode_numbers $lowertestdir $tmp.before.lo $tmp.after_copyup.lo
check_inode_numbers $uppertestdir $tmp.before.up $tmp.after_copyup.up

# Move all files to another dir
mkdir $lowertestdir.2 $uppertestdir.2

for f in $FILES; do
	mv $lowertestdir/$f $lowertestdir.2/
	mv $uppertestdir/$f $uppertestdir.2/
done

echo 3 > /proc/sys/vm/drop_caches

# Compare inode numbers before/after rename and drop caches
check_inode_numbers $lowertestdir.2 $tmp.after_copyup.lo $tmp.after_move.lo
check_inode_numbers $uppertestdir.2 $tmp.after_copyup.up $tmp.after_move.up

# Verify that the inode numbers survive a mount cycle
unmount_dirs
mount_dirs

# Compare inode numbers before/after mount cycle
check_inode_numbers $lowertestdir.2 $tmp.after_move.lo $tmp.after_cycle.lo
check_inode_numbers $uppertestdir.2 $tmp.after_move.up $tmp.after_cycle.up

unmount_dirs

echo "Silence is golden"
status=0
exit