tests/generic/612

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2020 Red Hat, Inc.  All Rights Reserved.
#
# FS QA Test 612
#
# Regression test for reflink corruption present as of:
# 78f0cc9d55cb "xfs: don't use delalloc extents for COW on files with extsize hints"
# and (inadvertently) fixed as of:
# 36adcbace24e "xfs: fill out the srcmap in iomap_begin"
# upstream, and in the 5.4 stable tree with:
# aee38af574a1 "xfs: trim IO to found COW extent limit"
#
. ./common/preamble
_begin_fstest auto quick clone

# Import common functions.
. ./common/filter
. ./common/reflink

# real QA test starts here

# Modify as appropriate.
_supported_fs generic
_require_test
_require_test_reflink

DIR=$TEST_DIR/dir.$seq
mkdir -p $DIR
rm -f $DIR/a $DIR/b

# This test essentially creates an existing COW extent which
# covers the first 1M, and then does another IO that overlaps it,
# but extends beyond it.  The bug was that we did not trim the
# new IO to the end of the existing COW extent, and so the IO
# extended past the COW blocks and corrupted the reflinked files(s).

# Make all files w/ 1m hints; create original 2m file
$XFS_IO_PROG -c "extsize 1048576" $DIR >/dev/null 2>&1
$XFS_IO_PROG -c "cowextsize 1048576" $DIR >/dev/null 2>&1

echo "Create file b"
$XFS_IO_PROG -f -c "pwrite -S 0x0 0 2m" -c fsync $DIR/b | _filter_xfs_io

# Make a reflinked copy
echo "Reflink copy from b to a"
cp --reflink=always $DIR/b $DIR/a

echo "Contents of b"
_hexdump $DIR/b

# Cycle mount to get stuff out of cache
_test_cycle_mount

# Create a 1m-hinted IO at offset 0, then
# do another IO that overlaps but extends past the 1m hint
echo "Write to a"
$XFS_IO_PROG -c "pwrite -S 0xa 0k -b 4k 4k" \
       -c "pwrite -S 0xa 4k -b 1m 1m" \
       $DIR/a | _filter_xfs_io

$XFS_IO_PROG -c fsync $DIR/a

echo "Contents of b now:"
_hexdump $DIR/b

# success, all done
status=0
exit