+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# FS QA Test No. 661
+#
+# Ensuring that copy on write in mmap mode works when the CoW
+# range originally covers multiple extents, some delalloc, some not.
+# (MMAP version of generic/195,194)
+# - Create a file.
+# - Reflink the odd blocks of the first file into the second file.
+# - Buffered write the even blocks of the second file.
+# - mmap CoW across the halfway mark, starting with the unwritten extent.
+# - Check that the files are now different where we say they're different.
+#
+. ./common/preamble
+_begin_fstest auto quick clone
+
+# Import common functions.
+. ./common/filter
+. ./common/reflink
+
+# real QA test starts here
+_require_scratch_reflink
+_require_scratch_delalloc
+_require_xfs_io_command "falloc"
+
+echo "Format and mount"
+_scratch_mkfs > $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1
+
+testdir=$SCRATCH_MNT/test-$seq
+mkdir $testdir
+
+echo "Create the original files"
+blksz=65536
+nr=64
+filesize=$((blksz * nr))
+_weave_reflink_holes $blksz $nr $testdir/file1 $testdir/file3 >> $seqres.full
+_scratch_cycle_mount
+
+echo "Compare files"
+md5sum $testdir/file1 | _filter_scratch
+md5sum $testdir/file3 | _filter_scratch
+md5sum $testdir/file3.chk | _filter_scratch
+
+echo "mmap CoW across the transition"
+cowoff=$((filesize / 4))
+cowsz=$((filesize / 2))
+_weave_reflink_holes_delalloc $blksz $nr $testdir/file3 >> $seqres.full
+mmapsz=$((cowoff + cowsz))
+_mwrite_byte 0x63 $cowoff $cowsz $mmapsz $testdir/file3 >> $seqres.full
+_mwrite_byte 0x63 $cowoff $cowsz $mmapsz $testdir/file3.chk >> $seqres.full
+_scratch_cycle_mount
+
+echo "Compare files"
+md5sum $testdir/file1 | _filter_scratch
+md5sum $testdir/file3 | _filter_scratch
+md5sum $testdir/file3.chk | _filter_scratch
+
+# success, all done
+status=0
+exit