#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2018 Red Hat, Inc.  All Rights Reserved.
#
# FS QA Test 443
#
# Regression test for the XFS rmapbt based extent swap algorithm. The extent
# swap algorithm for rmapbt=1 filesystems unmaps/remaps individual extents to
# rectify the rmapbt for each extent swapped between inodes. If one of the
# inodes happens to straddle the extent <-> btree format boundary (which can
# vary depending on inode size), the unmap/remap sequence can bounce the inodes
# back and forth between formats many times during the swap. Since extent ->
# btree format conversion requires a block allocation, this can consume more
# blocks than expected, lead to block reservation overrun and free space
# accounting inconsistency.
#
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.*
}

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

# remove previous $seqres.full before test
rm -f $seqres.full

# real QA test starts here

# Modify as appropriate.
_supported_fs generic
_supported_os Linux
_require_scratch
_require_test_program "punch-alternating"
_require_xfs_io_command "falloc"
_require_xfs_io_command "fpunch"
_require_xfs_io_command "swapext"

_scratch_mkfs | _filter_mkfs >> $seqres.full 2> $tmp.mkfs
_scratch_mount

# get fs block size
. $tmp.mkfs

file1=$SCRATCH_MNT/file1
file2=$SCRATCH_MNT/file2

# The goal is run an extent swap where one of the associated files has the
# minimum number of extents to remain in btree format. First, create a couple
# files with large enough extent counts (200 or so should be plenty) to ensure
# btree format on the largest possible inode size filesystems.
$XFS_IO_PROG -fc "falloc 0 $((400 * dbsize))" $file1
$here/src/punch-alternating $file1
$XFS_IO_PROG -fc "falloc 0 $((400 * dbsize))" $file2
$here/src/punch-alternating $file2

# Now run an extent swap at every possible extent count down to 0. Depending on
# inode size, one of these swaps will cover the boundary case between extent and
# btree format.
for i in $(seq 1 2 399); do
	# punch one extent from the tmpfile and swap
	$XFS_IO_PROG -c "fpunch $((i * dbsize)) $dbsize" $file2
	$XFS_IO_PROG -c "swapext $file2" $file1

	# punch the same extent from the old fork (now in file2) to resync the
	# extent counts and repeat
	$XFS_IO_PROG -c "fpunch $((i * dbsize)) $dbsize" $file2
done

# sanity check that no extents are left over
$XFS_IO_PROG -c "fiemap" $file1 | _filter_fiemap
$XFS_IO_PROG -c "fiemap" $file2 | _filter_fiemap

# failure results in fs corruption and possible assert failure
echo Silence is golden

# success, all done
status=0
exit