#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2020 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test No. btrfs/222
#
# Test an incremental send operation after doing a series of changes in a tree
# such that one inode gets two hardlinks with names and locations swapped with
# two other inodes that correspond to different directories, and one of these
# directories is the parent of the other directory.
#
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"

tmp=/tmp/$$
status=1	# failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15

_cleanup()
{
	cd /
	rm -fr $send_files_dir
	rm -f $tmp.*
}

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

# real QA test starts here
_supported_fs btrfs
_require_test
_require_scratch
_require_fssum

send_files_dir=$TEST_DIR/btrfs-test-$seq

rm -f $seqres.full
rm -fr $send_files_dir
mkdir $send_files_dir

_scratch_mkfs >>$seqres.full 2>&1
_scratch_mount

touch $SCRATCH_MNT/f1
touch $SCRATCH_MNT/f2
mkdir $SCRATCH_MNT/d1
mkdir $SCRATCH_MNT/d1/d2

# Filesystem looks like:
#
# .                                     (ino 256)
# |----- f1                             (ino 257)
# |----- f2                             (ino 258)
# |----- d1/                            (ino 259)
#        |----- d2/                     (ino 260)
#
$BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT \
	$SCRATCH_MNT/mysnap1 > /dev/null

$BTRFS_UTIL_PROG send -f $send_files_dir/1.snap \
	$SCRATCH_MNT/mysnap1 2>&1 1>/dev/null | _filter_scratch

# Now do a series of changes such that:
#
# *) inode 258 has one new hardlink and the previous name changed
#
# *) both names conflict with the old names of two other inodes:
#
#    1) the new name "d1" conflicts with the old name of inode 259, under
#       directory inode 256 (root)
#
#    2) the new name "d2" conflicts with the old name of inode 260 under
#       directory inode 259
#
# *) inodes 259 and 260 now have the old names of inode 258
#
# *) inode 257 is now located under inode 260 - an inode with a number
#    smaller than the inode (258) for which we created a second hard link
#    and swapped its names with inodes 259 and 260
#
ln $SCRATCH_MNT/f2 $SCRATCH_MNT/d1/f2_link
mv $SCRATCH_MNT/f1 $SCRATCH_MNT/d1/d2/f1

# Swap d1 and f2.
mv $SCRATCH_MNT/d1 $SCRATCH_MNT/tmp
mv $SCRATCH_MNT/f2 $SCRATCH_MNT/d1
mv $SCRATCH_MNT/tmp $SCRATCH_MNT/f2

# Swap d2 and f2_link
mv $SCRATCH_MNT/f2/d2 $SCRATCH_MNT/tmp
mv $SCRATCH_MNT/f2/f2_link $SCRATCH_MNT/f2/d2
mv $SCRATCH_MNT/tmp $SCRATCH_MNT/f2/f2_link

# Filesystem now looks like:
#
# .                                     (ino 256)
# |----- d1                             (ino 258)
# |----- f2/                            (ino 259)
#        |----- f2_link/                (ino 260)
#        |       |----- f1              (ino 257)
#        |
#        |----- d2                      (ino 258)
#

$BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT \
		 $SCRATCH_MNT/mysnap2 > /dev/null
$BTRFS_UTIL_PROG send -p $SCRATCH_MNT/mysnap1 -f $send_files_dir/2.snap \
		 $SCRATCH_MNT/mysnap2 2>&1 1>/dev/null | _filter_scratch

$FSSUM_PROG -A -f -w $send_files_dir/1.fssum $SCRATCH_MNT/mysnap1
$FSSUM_PROG -A -f -w $send_files_dir/2.fssum \
	-x $SCRATCH_MNT/mysnap2/mysnap1 $SCRATCH_MNT/mysnap2

# Now recreate the filesystem by receiving both send streams and verify we get
# the same content that the original filesystem had.
_scratch_unmount
_scratch_mkfs >>$seqres.full 2>&1
_scratch_mount

$BTRFS_UTIL_PROG receive -f $send_files_dir/1.snap $SCRATCH_MNT > /dev/null

# The receive operation below used to fail with the following error:
#
#    ERROR: rename d1/d2 -> o260-6-0 failed: No such file or directory
#
# Because when processing inode 258, the kernel orphanized first inode 259,
# renaming it from "d1" to "o259-6-0", since it the new reference named "d1"
# for inode 258 conflicts with the old one of inode 259, which was not yet
# processed. After that, because the new reference named "d2" for inode 258
# conflicts with the old reference of the not yet processed inode 260, it
# tried to orphanize inode 260 - however the corresponding rename operation
# used a source path of "d1/d2", instead of "o259-6-0/d2".
#
$BTRFS_UTIL_PROG receive -f $send_files_dir/2.snap $SCRATCH_MNT > /dev/null

$FSSUM_PROG -r $send_files_dir/1.fssum $SCRATCH_MNT/mysnap1
$FSSUM_PROG -r $send_files_dir/2.fssum $SCRATCH_MNT/mysnap2

status=0
exit