#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2022 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test No. 256
#
# Test that defragging files with very small sizes works and does not result in
# any crash, hang or corruption.
#
# The regression is fixed by a patch with the following subject:
#
#   "btrfs: fix too long loop when defragging a 1 byte file"
#
. ./common/preamble
_begin_fstest auto quick defrag

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

. ./common/filter

_supported_fs btrfs
_require_scratch
_require_fssum

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

checksums_file="$TEST_DIR/btrfs-test-$seq-checksums"
block_size=$(_get_block_size "$SCRATCH_MNT")

# Test file sizes of 0, 1, 512, 1K, 2K, 4K, 8K, 16K, 32K and 64K bytes.
file_sizes=( 0 1 512 1024 2048 4096 8192 16384 32768 65536 )

# Create the files and compute their checksums.
for sz in ${file_sizes[@]}; do
	byte=$(printf "0x%x" $((RANDOM % 255)))
	$XFS_IO_PROG -f -c "pwrite -S $byte 0 $sz" "$SCRATCH_MNT/f_$sz" >> $seqres.full
done

# Compute the checksums.
$FSSUM_PROG -A -f -w "$checksums_file" "$SCRATCH_MNT"

# Now defrag each file.
for sz in ${file_sizes[@]}; do
	echo "Defragging file with $sz bytes..." >> $seqres.full
	# In new versions of btrfs-progs (6.0+), the defrag command outputs to
	# stdout the path of the files it operates on. So ignore that.
	$BTRFS_UTIL_PROG filesystem defragment "$SCRATCH_MNT/f_$sz" > /dev/null
done

# Verify the checksums after the defrag operations.
$FSSUM_PROG -r "$checksums_file" "$SCRATCH_MNT"

# Unmount and mount again, this clears the page cache and we want to see that
# no corruptions were persisted.
_scratch_cycle_mount

# Verify the checksums again.
$FSSUM_PROG -r "$checksums_file" "$SCRATCH_MNT"

# success, all done
status=0
exit