tests/generic/771

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2025 SUSE Linux Products GmbH.  All Rights Reserved.
#
# FS QA Test 771
#
# Create two files, the first one with some data, and then fsync both files.
# The first file is fsynced after removing its hardlink. After a power failure
# we expect the fs to be mountable and for only the second file to be present.
#
. ./common/preamble
_begin_fstest auto quick log

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

. ./common/filter
. ./common/dmflakey

_require_scratch
_require_test_program unlink-fsync
_require_dm_target flakey

[ "$FSTYP" = "btrfs" ] && _fixed_by_kernel_commit 0a32e4f0025a \
	"btrfs: fix log tree replay failure due to file with 0 links and extents"

_scratch_mkfs >> $seqres.full 2>&1 || _fail "mkfs failed"
_require_metadata_journaling $SCRATCH_DEV
_init_flakey
_mount_flakey

# Create our first test file with some data.
mkdir $SCRATCH_MNT/testdir
$XFS_IO_PROG -f -c "pwrite 0K 64K" $SCRATCH_MNT/testdir/foo | _filter_xfs_io

# fsync our first test file after unlinking it - we keep an fd open for the
# file, unlink it and then fsync the file using that fd, so that we log/journal
# a file with 0 hard links.
$here/src/unlink-fsync $SCRATCH_MNT/testdir/foo

# Create another test file and fsync it.
touch $SCRATCH_MNT/testdir/bar
$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/testdir/bar

# Simulate a power failure and replay the log/journal.
# On btrfs we had a bug where the replay procedure failed, causing the fs mount
# to fail, because the first test file has extents and the second one, which has
# an higher inode number, has a non-zero (1) link count - the replay code got
# confused and thought the extents belonged to the second file and then it
# failed when trying to open a non-existing inode to replay the extents.
_flakey_drop_and_remount

# File foo should not exist and file bar should exist.
ls -1 $SCRATCH_MNT/testdir

_exit 0