#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2017 Synology Inc. All Rights Reserved.
#
# FS QA Test No. btrfs/135
#
# Test that an incremental send operation works when in both snapshots there are
# two directory inodes that have the same number but different generations and
# have an entry with the same name that corresponds to different inodes in each
# snapshot.
#
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/f
mkdir $SCRATCH_MNT/d1
mkdir $SCRATCH_MNT/d259_old
mv $SCRATCH_MNT/d1 $SCRATCH_MNT/d259_old/d1

# Filesystem looks like:
#
# .                                                             (ino 256)
# |--- f                                                        (ino 257)
# |
# |--- d259_old/                                                (ino 259)
#         |--- d1/                                              (ino 258)
#
$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

_scratch_unmount
_scratch_mkfs >>$seqres.full 2>&1
_scratch_mount
mkdir $SCRATCH_MNT/d1
mkdir $SCRATCH_MNT/dir258
mkdir $SCRATCH_MNT/dir259
mv $SCRATCH_MNT/d1 $SCRATCH_MNT/dir259/d1

# Filesystem now looks like:
#
# .                                                             (ino 256)
# |--- dir258/                                                  (ino 258)
# |
# |--- dir259/                                                  (ino 259)
#        |--- d1/                                               (ino 257)
#
# Notice that at this point all inodes have a generation with value 7, which is
# the generation value for a brand new filesystem.

# Now create the second snapshot. This makes the filesystem's current generation
# value to increase to the value 8, due to a transaction commit performed by the
# snapshot creation ioctl.
$BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT \
	$SCRATCH_MNT/mysnap2 > /dev/null

# Now receive the first snapshot created in the first filesystem.
# Before creating any inodes, the receive command creates the first snapshot,
# which causes a transaction commit and therefore bumps the filesystem's current
# generation to the value 9. All the inodes created end up getting a generation
# value of 9 and the snapshot's root inode (256) gets a generation value of 8.
$BTRFS_UTIL_PROG receive -f $send_files_dir/1.snap $SCRATCH_MNT > /dev/null
rm $send_files_dir/1.snap

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

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

# 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
$FSSUM_PROG -r $send_files_dir/1.fssum $SCRATCH_MNT/mysnap1
# The receive of the incremental send stream used to fail because it contained
# a rmdir operation with an invalid path. The output of the receive command,
# with verbose mode (argument -vv), was the following:
#
# utimes
# unlink f
# mkdir o257-7-0
# mkdir o259-7-0
# rename o257-7-0 -> o259-7-0/d1
# chown o259-7-0/d1 - uid=0, gid=0
# chmod o259-7-0/d1 - mode=0755
# utimes o259-7-0/d1
# rmdir o258-9-0
# ERROR: rmdir o258-9-0 failed: No such file or directory
#
# When the kernel was computing the send stream and processing inode 258, it
# noticed that in both snapshots this inode is a direct child of inode 259, and
# that in both snapshots inode 259 as an entry with the name "d1". Because of
# that it decided (incorrectly) to issue an rmdir operation using the orphanized
# name of the inode 258 from the parent snapshot (which has a generation of 9).
# However that decision to send an rmdir operation due to the dentry collision
# was incorrect because the inodes with number 259 in both snapshots are not the
# same, they have different generations.
#
$BTRFS_UTIL_PROG receive -f $send_files_dir/2.snap $SCRATCH_MNT > /dev/null
$FSSUM_PROG -r $send_files_dir/2.fssum $SCRATCH_MNT/mysnap2

status=0
exit