#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2015 Red Hat, Inc. All Rights Reserved.
#
# FS QA Test 074-extsz-hints-vs-maxextlen
#
# Check some extent size hint boundary conditions that can result in
# MAXEXTLEN overflows.
#
# In xfs_bmap_extsize_align(), we had,
# 	if ((temp = (align_alen % extsz))) {
# 		align_alen += extsz - temp;
# 	}
# align_alen had the value of 2097151 (i.e. MAXEXTLEN) blocks. extsz had
# the value of 4096 blocks.
#
# align_alen % extsz will be 4095. so align_alen will end up having
# 2097151 + (4096 - 4095) = 2097152 i.e. (MAXEXTLEN + 1). Thus the length
# of the new extent will be larger than MAXEXTLEN. This will later cause
# the bmbt leaf to have an entry whose length is set to zero block count.
#
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"

_cleanup()
{
	cd /
	_destroy_loop_device $LOOP_DEV
	rm -f $tmp.* $LOOP_FILE
}

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

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

# real QA test starts here
_supported_fs xfs
_supported_os Linux

rm -f $seqres.full

_require_test
_require_xfs_io_command "falloc"

# we use loop devices for this so that we can create large files for prealloc
# without having to care about the underlying device size.
_require_loop

LOOP_FILE=$TEST_DIR/$seq.img
LOOP_MNT=$TEST_DIR/$seq.mnt
mkdir -p $LOOP_MNT
$XFS_IO_PROG -ft -c "truncate 1t" $LOOP_FILE >> $seqres.full
LOOP_DEV=`_create_loop_device $LOOP_FILE`

_mkfs_dev -d size=260g,agcount=2 $LOOP_DEV
_mount $LOOP_DEV $LOOP_MNT

BLOCK_SIZE=$(_get_file_block_size $LOOP_MNT)

# Corrupt the BMBT by creating extents larger than MAXEXTLEN
# For 4k blocksize, MAXEXTLEN * 4k = 2097151 * 4k = 8589930496 = ~8GiB
$XFS_IO_PROG -ft \
	-c "extsize $(($BLOCK_SIZE * 4096))" \
	-c "falloc 0 $(($BLOCK_SIZE * 2097152))" \
	$LOOP_MNT/foo >> $seqres.full

umount $LOOP_MNT
_check_xfs_filesystem $LOOP_DEV none none

_mkfs_dev -f $LOOP_DEV
_mount $LOOP_DEV $LOOP_MNT

# check we trim both ends of the extent approproiately; this will fail
# on 1k block size filesystems without the correct fixes in place.
$XFS_IO_PROG -ft \
	-c "extsize 1g" \
	-c "falloc 1023m 2g" \
	$LOOP_MNT/foo >> $seqres.full

umount $LOOP_MNT
_check_xfs_filesystem $LOOP_DEV none none

# success, all done
echo "Silence is golden"
status=0
exit