diff --git a/tests/xfs/440 b/tests/xfs/440
new file mode 100755
index 00000000..3ce771a8
--- /dev/null
+++ b/tests/xfs/440
@@ -0,0 +1,106 @@
+#! /bin/bash
+# FS QA Test 440
+#
+# Regression test for the XFS rmapbt based extent swap algorithm. The extent
+# swap algorithm for rmapbt=1 filesystems unmaps/remaps individual extents to
+# rectify the rmapbt for each extent swapped between inodes. If one of the
+# inodes happens to straddle the extent <-> btree format boundary (which can
+# vary depending on inode size), the unmap/remap sequence can bounce the inodes
+# back and forth between formats many times during the swap. Since extent ->
+# btree format conversion requires a block allocation, this can consume more
+# blocks than expected, lead to block reservation overrun and free space
+# accounting inconsistency.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2018 Red Hat, Inc.  All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+#
+
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/punch
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os Linux
+_require_scratch
+_require_test_program "punch-alternating"
+_require_xfs_io_command "falloc"
+_require_xfs_io_command "fpunch"
+_require_xfs_io_command "swapext"
+
+_scratch_mkfs | _filter_mkfs >> $seqres.full 2> $tmp.mkfs
+_scratch_mount || _fail "mount failed"
+
+# get fs block size
+. $tmp.mkfs
+
+file1=$SCRATCH_MNT/file1
+file2=$SCRATCH_MNT/file2
+
+# The goal is run an extent swap where one of the associated files has the
+# minimum number of extents to remain in btree format. First, create a couple
+# files with large enough extent counts (200 or so should be plenty) to ensure
+# btree format on the largest possible inode size filesystems.
+$XFS_IO_PROG -fc "falloc 0 $((400 * dbsize))" $file1
+./src/punch-alternating $file1
+$XFS_IO_PROG -fc "falloc 0 $((400 * dbsize))" $file2
+./src/punch-alternating $file2
+
+# Now run an extent swap at every possible extent count down to 0. Depending on
+# inode size, one of these swaps will cover the boundary case between extent and
+# btree format.
+for i in $(seq 1 2 399); do
+	# punch one extent from the tmpfile and swap
+	$XFS_IO_PROG -c "fpunch $((i * dbsize)) $dbsize" $file2
+	$XFS_IO_PROG -c "swapext $file2" $file1
+
+	# punch the same extent from the old fork (now in file2) to resync the
+	# extent counts and repeat
+	$XFS_IO_PROG -c "fpunch $((i * dbsize)) $dbsize" $file2
+done
+
+# sanity check that no extents are left over
+$XFS_IO_PROG -c "fiemap" $file1 | _filter_fiemap
+$XFS_IO_PROG -c "fiemap" $file2 | _filter_fiemap
+
+# failure results in fs corruption and possible assert failure
+echo Silence is golden
+
+# success, all done
+status=0
+exit
diff --git a/tests/xfs/440.out b/tests/xfs/440.out
new file mode 100644
index 00000000..fb8dc21f
--- /dev/null
+++ b/tests/xfs/440.out
@@ -0,0 +1,2 @@
+QA output created by 440
+Silence is golden
diff --git a/tests/xfs/group b/tests/xfs/group
index cf81451d..ad30be42 100644
--- a/tests/xfs/group
+++ b/tests/xfs/group
@@ -437,3 +437,4 @@
 437 auto quick other
 438 auto quick quota dangerous
 439 auto quick fuzzers log
+440 auto quick ioctl fsr
