#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test No. 090
#
# Test that after syncing the filesystem, adding a hard link to a file,
# syncing the filesystem again, doing a write to the file that increases
# its size and then doing a fsync against that file, durably persists the
# data written to the file. That is, after log/journal replay, the data
# is available.
#
# This test is motivated by a bug found in btrfs.
#
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"

here=`pwd`
tmp=/tmp/$$
status=1	# failure is the default!

_cleanup()
{
	_cleanup_flakey
	rm -f $tmp.*
}
trap "_cleanup; exit \$status" 0 1 2 3 15

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

# real QA test starts here
_supported_fs generic
_require_scratch
_require_hardlinks
_require_dm_target flakey

rm -f $seqres.full

_scratch_mkfs >> $seqres.full 2>&1
_require_metadata_journaling $SCRATCH_DEV
_init_flakey
_mount_flakey

# Create the test file with some initial data and then fsync it.
# The fsync here is only needed to trigger the issue in btrfs, as it causes the
# the flag BTRFS_INODE_NEEDS_FULL_SYNC to be removed from the btrfs inode.
$XFS_IO_PROG -f -c "pwrite -S 0xaa 0 32k" \
		-c "fsync" \
		$SCRATCH_MNT/foo | _filter_xfs_io
sync

# Add a hard link to our file.
# On btrfs this sets the flag BTRFS_INODE_COPY_EVERYTHING on the btrfs inode,
# which is a necessary condition to trigger the issue.
ln $SCRATCH_MNT/foo $SCRATCH_MNT/bar

# Sync the filesystem to force a commit of the current btrfs transaction, this
# is a necessary condition to trigger the bug on btrfs.
sync

# Now append more data to our file, increasing its size, and fsync the file.
# In btrfs because the inode flag BTRFS_INODE_COPY_EVERYTHING was set and the
# write path did not update the inode item in the btree nor the delayed inode
# item (in memory structure) in the current transaction (created by the fsync
# handler), the fsync did not record the inode's new i_size in the fsync
# log/journal. This made the data unavailable after the fsync log/journal is
# replayed.
$XFS_IO_PROG -c "pwrite -S 0xbb 32K 32K" \
		-c "fsync" \
		$SCRATCH_MNT/foo | _filter_xfs_io

echo "File content after fsync and before crash:"
od -t x1 $SCRATCH_MNT/foo

_flakey_drop_and_remount

echo "File content after crash and log replay:"
od -t x1 $SCRATCH_MNT/foo

status=0
exit