#! /bin/bash
# FS QA Test No. btrfs/083
#
# Test for incremental send where the difference between the parent and child
# snapshots is that a directory A was renamed and a directory B was renamed to
# the name directory A had before (in the parent snapshot), but directory A's
# rename must happen before some other directory C is renamed.
#
# This issue was fixed by the following linux kernel btrfs patch:
#
#   Btrfs: incremental send, don't rename a directory too soon
#
#-----------------------------------------------------------------------
# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
# Author: Filipe Manana <fdmanana@suse.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#-----------------------------------------------------------------------
#

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()
{
	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
_supported_os Linux
_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

mkdir $SCRATCH_MNT/a
mkdir $SCRATCH_MNT/b
mkdir $SCRATCH_MNT/c
touch $SCRATCH_MNT/a/file

mkdir $SCRATCH_MNT/d
mkdir $SCRATCH_MNT/e
touch $SCRATCH_MNT/e/file2
mkdir $SCRATCH_MNT/f

# Filesystem looks like:
#
# .                                       (ino 256)
# |---- a/                                (ino 257)
# |     |---- file                        (ino 260)
# |
# |---- b/                                (ino 258)
# |---- c/                                (ino 259)
# |---- d/                                (ino 261)
# |---- e/                                (ino 262)
# |     |--- file2                        (ino 263)
# |
# |---- f/                                (ino 264)
#
_run_btrfs_util_prog subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap1

# Now make inode 257 a child of inode 259 and rename inode 258 to the name that
# inode 257 had before. When the incremental send processes inode 257, it can't
# do the rename immediately because inode 259 must be renamed first, so inode's
# 257 rename is delayed and happens after the rename for inode 259 is done.
# Since send processes inodes by ascending order of their number, inode 258
# can't be renamed before inode 257 is renamed and therefore must be delayed
# as well. So the send stream must issue rename commands in the following order:
#
# 1 - rename inode 259 ('c' -> 'x')
# 2 - rename inode 257 ('a' -> 'x/y')
# 3 - rename inode 258 ('b' -> 'a')
#
# Before the fix mentioned above, the send stream attempted to rename inode 258
# before inode 257 was renamed, resulting in a client error mentioning
# 'directory not empty'.
#
# Same logic applies to 'd', 'e' and 'f', but the difference is that in the
# second snapshot 'e' is associated to an inode with a lower inode number than
# in the first snapshot.
#
mv $SCRATCH_MNT/c $SCRATCH_MNT/x
mv $SCRATCH_MNT/a $SCRATCH_MNT/x/y
mv $SCRATCH_MNT/b $SCRATCH_MNT/a

mv $SCRATCH_MNT/f $SCRATCH_MNT/f2
mv $SCRATCH_MNT/e $SCRATCH_MNT/f2/e2
mv $SCRATCH_MNT/d $SCRATCH_MNT/e

# Filesystem now looks like:
#
#
# .                                       (ino 256)
# |---- a/                                (ino 258)
# |---- x/                                (ino 259)
# |     |---- y/                          (ino 257)
# |           |----- file                 (ino 260)
# |
# |---- e/                                (ino 261)
# |---- f2/                               (ino 264)
# |     |----- e2/                        (ino 262)
#              |---- file2                (ino 263)

_run_btrfs_util_prog subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap2

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

_run_btrfs_util_prog send $SCRATCH_MNT/mysnap1 -f $send_files_dir/1.snap
_run_btrfs_util_prog send -p $SCRATCH_MNT/mysnap1 $SCRATCH_MNT/mysnap2 \
	-f $send_files_dir/2.snap

# 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

_run_btrfs_util_prog receive $SCRATCH_MNT -f $send_files_dir/1.snap
run_check $FSSUM_PROG -r $send_files_dir/1.fssum $SCRATCH_MNT/mysnap1

_run_btrfs_util_prog receive $SCRATCH_MNT -f $send_files_dir/2.snap
run_check $FSSUM_PROG -r $send_files_dir/2.fssum $SCRATCH_MNT/mysnap2

echo "Silence is golden"

status=0
exit
