#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2022-2024 Oracle.  All Rights Reserved.
#
# FS QA Test No. 607
#
# This is a regression test for "xfs: Fix false ENOSPC when performing direct
# write on a delalloc extent in cow fork".  If there is a lot of free space but
# it is very fragmented, it's possible that a very large delalloc reservation
# could be created in the CoW fork by a buffered write.  If a directio write
# tries to convert the delalloc reservation to a real extent, it's possible
# that the allocation will succeed but fail to convert even the first block of
# the directio write range.  In this case, XFS will return ENOSPC even though
# all it needed to do was to keep converting until the allocator returns ENOSPC
# or the first block of the direct write got some space.
#
. ./common/preamble
_begin_fstest auto quick clone

_cleanup()
{
	cd /
	rm -f $file1 $file2 $fragmentedfile
}

# Import common functions.
. ./common/reflink
. ./common/inject

# real QA test starts here
_fixed_by_kernel_commit d62113303d69 \
	"xfs: Fix false ENOSPC when performing direct write on a delalloc extent in cow fork"

# Modify as appropriate.
_supported_fs xfs
_require_test_program "punch-alternating"
_require_test_reflink
_require_xfs_io_error_injection "bmap_alloc_minlen_extent"
_require_test_delalloc

file1=$TEST_DIR/file1.$seq
file2=$TEST_DIR/file2.$seq
fragmentedfile=$TEST_DIR/fragmentedfile.$seq

rm -f $file1 $file2 $fragmentedfile

# COW operates on pages, so we must not perform operations in units smaller
# than a page.
blksz=$(_get_file_block_size $TEST_DIR)
pagesz=$(_get_page_size)
if (( $blksz < $pagesz )); then
	blksz=$pagesz
fi

echo "Create source file"
$XFS_IO_PROG -f -c "pwrite 0 $((blksz * 256))" $file1 >> $seqres.full

sync

echo "Create Reflinked file"
_cp_reflink $file1 $file2 >> $seqres.full

echo "Set cowextsize"
$XFS_IO_PROG -c "cowextsize $((blksz * 128))" -c stat $file1 >> $seqres.full

echo "Fragment FS"
$XFS_IO_PROG -f -c "pwrite 0 $((blksz * 512))" $fragmentedfile >> $seqres.full
sync
$here/src/punch-alternating $fragmentedfile

echo "Allocate block sized extent from now onwards"
_test_inject_error bmap_alloc_minlen_extent 1

echo "Create big delalloc extent in CoW fork"
$XFS_IO_PROG -c "pwrite 0 $blksz" $file1 >> $seqres.full

sync

$XFS_IO_PROG -c 'bmap -elpv' -c 'bmap -celpv' $file1 &>> $seqres.full

echo "Direct I/O write at offset 3FSB"
$XFS_IO_PROG -d -c "pwrite $((blksz * 3)) $((blksz * 2))" $file1 >> $seqres.full

# success, all done
status=0
exit