#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2024 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test 310
#
# Make sure reading on an compressed inline extent is behaving correctly
#
. ./common/preamble
_begin_fstest auto quick compress

_supported_fs btrfs
_require_scratch

# This test require inlined compressed extents creation, and all the writes
# are designed for 4K sector size.
_require_btrfs_inline_extents_creation
_require_btrfs_support_sectorsize 4096

_fixed_by_kernel_commit e01a83e12604 \
	"Revert \"btrfs: zstd: fix and simplify the inline extent decompression\""

# The correct md5 for the correct 4K file filled with "0xcd"
md5sum_correct="5fed275e7617a806f94c173746a2a723"

workload()
{
	local algo="$1"

	echo "=== Testing compression algorithm ${algo} ===" >> $seqres.full
	_scratch_mkfs >> $seqres.full
	_scratch_mount -o compress=${algo}

	_pwrite_byte 0xcd 0 4k "$SCRATCH_MNT/inline_file" > /dev/null
	result=$(_md5_checksum "$SCRATCH_MNT/inline_file")
	echo "after initial write, md5sum=${result}" >> $seqres.full
	if [ "$result" != "$md5sum_correct" ]; then
		_fail "initial write results incorrect content for \"$algo\""
	fi
	# Writeback data to get correct fiemap result, or we got FIEMAP_DEALLOC
	# without compression/inline flags.
	sync

	$XFS_IO_PROG -c "fiemap -v" $SCRATCH_MNT/inline_file | tail -n 1 > $tmp.fiemap
	cat $tmp.fiemap >> $seqres.full
	# Make sure we got an inlined compressed file extent.
	# 0x200 means inlined, 0x100 means not block aligned, 0x8 means encoded
	# (compressed in this case), and 0x1 means the last extent.
	if ! grep -q "0x309" $tmp.fiemap; then
		rm -f -- $tmp.fiemap
		_notrun "No compressed inline extent created, maybe subpage?"
	fi
	rm -f -- $tmp.fiemap

	# Unmount to clear the page cache.
	_scratch_cycle_mount

	# For v6.8-rc1 without the revert or the newer fix, this would
	# lead to VM_BUG_ON() thus crash
	result=$(_md5_checksum "$SCRATCH_MNT/inline_file")
	echo "after cycle mount, md5sum=${result}" >> $seqres.full
	if [ "$result" != "$md5sum_correct" ]; then
		_fail "read for compressed inline extent failed for \"$algo\""
	fi
	_scratch_unmount
	_check_scratch_fs
}

algo_list=($(_btrfs_compression_algos))
for algo in ${algo_list[@]}; do
	workload $algo
done

echo "Silence is golden"

status=0
exit