#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2021 Red Hat, Inc.  All Rights Reserved.
#
# FS QA Test 542
#
# Test that COW writeback that overlaps non-shared delalloc blocks does not
# leave around stale delalloc blocks on I/O failure. This triggers assert
# failures and free space accounting corruption on XFS. Fixed by upstream kernel
# commit 5ca5916b6bc9 ("xfs: punch out data fork delalloc blocks on COW
# writeback failure").
#
. ./common/preamble
_begin_fstest auto quick clone

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

# Import common functions.
. ./common/reflink
. ./common/dmflakey

# real QA test starts here
_supported_fs xfs
_fixed_by_kernel_commit 5ca5916b6bc9 \
	"xfs: punch out data fork delalloc blocks on COW writeback failure"

_require_scratch_reflink
_require_cp_reflink
_require_xfs_io_command "cowextsize"
_require_flakey_with_error_writes

_scratch_mkfs >> $seqres.full
_init_flakey
_mount_flakey

blksz=$(_get_file_block_size $SCRATCH_MNT)

# Set the COW extent size hint to guarantee COW fork preallocation occurs over a
# bordering block offset.
$XFS_IO_PROG -c "cowextsize $((blksz * 2))" $SCRATCH_MNT >> $seqres.full

# create two files that share a single block
$XFS_IO_PROG -fc "pwrite $blksz $blksz" $SCRATCH_MNT/file1 >> $seqres.full
$XFS_IO_PROG -fc "reflink $SCRATCH_MNT/file1" \
	-c fsync $SCRATCH_MNT/file2 >> $seqres.full

# Perform a buffered write across the shared and non-shared blocks. On XFS, this
# creates a COW fork extent that covers the shared block as well as the just
# created non-shared delalloc block. Fail the writeback to verify that all
# delayed allocation is cleaned up properly.
_load_flakey_table $FLAKEY_ERROR_WRITES
len=$((blksz * 2))
$XFS_IO_PROG -c "pwrite 0 $len" \
	-c "sync_range -w 0 $len" \
	-c "sync_range -a 0 $len" $SCRATCH_MNT/file2 >> $seqres.full
_load_flakey_table $FLAKEY_ALLOW_WRITES

# Try a post-fail reflink and then unmount. Both of these are known to produce
# errors and/or assert failures on XFS if we trip over a stale delalloc block.
_cp_reflink $SCRATCH_MNT/file2 $SCRATCH_MNT/file3
_unmount_flakey

# success, all done
status=0
exit