diff --git a/tests/generic/904 b/tests/generic/904
new file mode 100755
index 00000000..c1cca379
--- /dev/null
+++ b/tests/generic/904
@@ -0,0 +1,135 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# FS QA Test No. xxx
+#
+# See what happens if we MMAP CoW blocks 2-4 of a page's worth of blocks when
+# the surrounding blocks vary between unwritten/regular/delalloc/hole.
+# (MMAP version of generic/229,238)
+#
+# This test is dependent on the system page size, so we cannot use md5 in
+# the golden output; we can only compare to a check file.
+#
+. ./common/preamble
+_begin_fstest auto quick clone
+
+# Override the default cleanup function.
+_cleanup()
+{
+    cd /
+    rm -rf $tmp.* $testdir
+}
+
+# Import common functions.
+. ./common/filter
+. ./common/reflink
+
+# real QA test starts here
+_require_scratch_reflink
+_require_xfs_io_command "falloc"
+
+pagesz=$(getconf PAGE_SIZE)
+blksz=$((pagesz / 4))
+
+echo "Format and mount"
+_scratch_mkfs_blocksized $blksz > $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1
+
+testdir=$SCRATCH_MNT/test-$seq
+mkdir $testdir
+
+real_blksz=$(_get_file_block_size $testdir)
+test $real_blksz != $blksz && _notrun "Failed to format with small blocksize."
+
+runtest() {
+	echo "runtest $1 $2"
+	b2=$1
+	b4=$2
+	dir=$3
+
+	echo "Create the original files"
+	mkdir -p $dir
+	_pwrite_byte 0x61 0 $pagesz $dir/file1 >> $seqres.full
+
+	$XFS_IO_PROG -f -c "truncate $pagesz" $dir/file2 >> $seqres.full
+	$XFS_IO_PROG -f -c "truncate $pagesz" $dir/file2.chk >> $seqres.full
+
+	case $b2 in
+	"regular")
+		_pwrite_byte 0x61 $blksz $blksz $dir/file2 >> $seqres.full
+		_pwrite_byte 0x61 $blksz $blksz $dir/file2.chk >> $seqres.full
+		;;
+	"unwritten")
+		$XFS_IO_PROG -f -c "falloc -k $blksz $blksz" $dir/file2 >> $seqres.full
+		_pwrite_byte 0x00 $blksz $blksz $dir/file2.chk >> $seqres.full
+		;;
+	"hole")
+		;;
+	esac
+
+	case $b4 in
+	"regular")
+		_pwrite_byte 0x61 $((blksz * 3)) $blksz $dir/file2 >> $seqres.full
+		_pwrite_byte 0x61 $((blksz * 3)) $blksz $dir/file2.chk >> $seqres.full
+		;;
+	"unwritten")
+		$XFS_IO_PROG -f -c "falloc -k $((blksz * 3)) $blksz" $dir/file2 >> $seqres.full
+		_pwrite_byte 0x00 $((blksz * 3)) $blksz $dir/file2.chk >> $seqres.full
+		;;
+	"hole")
+		;;
+	esac
+
+	_reflink_range $dir/file1 $blksz $dir/file2 $((blksz * 2)) $blksz >> $seqres.full
+	_pwrite_byte 0x61 $((blksz * 2)) $blksz $dir/file2.chk >> $seqres.full
+	_scratch_cycle_mount
+
+	echo "Compare files"
+	cmp -s $dir/file1 $dir/file2 && echo "file1 and file2 should not match."
+	cmp -s $dir/file2 $dir/file2.chk || echo "file2 and file2.chk don't match."
+
+	echo "CoW and unmount"
+	if [ $b2 = "delalloc" ]; then
+		_pwrite_byte 0x61 $blksz $blksz $dir/file2 >> $seqres.full
+		_pwrite_byte 0x61 $blksz $blksz $dir/file2.chk >> $seqres.full
+	fi
+
+	if [ $b4 = "delalloc" ]; then
+		_pwrite_byte 0x61 $((blksz * 3)) $blksz $dir/file2 >> $seqres.full
+		_pwrite_byte 0x61 $((blksz * 3)) $blksz $dir/file2.chk >> $seqres.full
+	fi
+
+	$XFS_IO_PROG -f -c "mmap 0 $pagesz" \
+        -c "pwrite -S 0x63 $((blksz + 17)) $((blksz * 3 - 34))" $dir/file2 >> $seqres.full
+	$XFS_IO_PROG -f -c "mmap 0 $pagesz" \
+        -c "pwrite -S 0x63 $((blksz + 17)) $((blksz * 3 - 34))" $dir/file2.chk >> $seqres.full
+	_scratch_cycle_mount
+
+	echo "Compare files"
+	cmp -s $dir/file1 $dir/file2 && echo "file1 and file2 should not match."
+	cmp -s $dir/file2 $dir/file2.chk || echo "file2 and file2.chk don't match."
+}
+
+runtest regular delalloc "$testdir/r-d"
+runtest regular unwritten "$testdir/r-u"
+runtest regular hole "$testdir/r-h"
+runtest regular regular "$testdir/r-r"
+
+runtest hole delalloc "$testdir/h-d"
+runtest hole unwritten "$testdir/h-u"
+runtest hole hole "$testdir/h-h"
+runtest hole regular "$testdir/h-r"
+
+runtest unwritten delalloc "$testdir/u-d"
+runtest unwritten unwritten "$testdir/u-u"
+runtest unwritten hole "$testdir/u-h"
+runtest unwritten regular "$testdir/u-r"
+
+runtest delalloc delalloc "$testdir/d-d"
+runtest delalloc unwritten "$testdir/d-u"
+runtest delalloc hole "$testdir/d-h"
+runtest delalloc regular "$testdir/d-r"
+
+# success, all done
+status=0
+exit
diff --git a/tests/generic/904.out b/tests/generic/904.out
new file mode 100644
index 00000000..f84bbe6d
--- /dev/null
+++ b/tests/generic/904.out
@@ -0,0 +1,82 @@
+QA output created by 904
+Format and mount
+runtest regular delalloc
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest regular unwritten
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest regular hole
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest regular regular
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest hole delalloc
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest hole unwritten
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest hole hole
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest hole regular
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest unwritten delalloc
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest unwritten unwritten
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest unwritten hole
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest unwritten regular
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest delalloc delalloc
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest delalloc unwritten
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest delalloc hole
+Create the original files
+Compare files
+CoW and unmount
+Compare files
+runtest delalloc regular
+Create the original files
+Compare files
+CoW and unmount
+Compare files
