diff --git a/common/filter b/common/filter
index 1ef342b5..39ea140c 100644
--- a/common/filter
+++ b/common/filter
@@ -295,6 +295,17 @@ _filter_scratch()
 	    -e "/.use_space/d"
 }
 
+_filter_testdir_and_scratch()
+{
+	# filter both $TEST_DIR and $SCRATCH_MNT, but always filter the longer
+	# string first if the other string is a substring of the first one
+	if echo "$TEST_DIR" | grep -q "$SCRATCH_MNT"; then
+		_filter_test_dir | _filter_scratch
+	else
+		_filter_scratch | _filter_test_dir
+	fi
+}
+
 # Turn any device in the scratch pool into SCRATCH_DEV
 _filter_scratch_pool()
 {
@@ -311,7 +322,7 @@ _filter_quota()
 {
 	# Long dev name might be split onto its own line; last
 	# seds remove that newline if present
-	_filter_scratch | _filter_test_dir | _filter_spaces | \
+	_filter_testdir_and_scratch | _filter_spaces | \
 	sed -e 'N;s/SCRATCH_DEV\n/SCRATCH_DEV/g' | \
 	sed -e 'N;s/TEST_DEV\n/TEST_DEV/g'
 }
diff --git a/tests/btrfs/029 b/tests/btrfs/029
index c390c95f..b6e2dbb0 100755
--- a/tests/btrfs/029
+++ b/tests/btrfs/029
@@ -66,19 +66,14 @@ _scratch_mkfs > /dev/null 2>&1
 _scratch_mount
 $XFS_IO_PROG -f -c 'pwrite -S 0x61 0 9000' $SCRATCH_MNT/original >> $seqres.full
 
-_filter_testdirs()
-{
-    _filter_test_dir | _filter_scratch
-}
-
 _create_reflinks()
 {
     # auto reflink, should fall back to non-reflink
     rm -rf $2
     echo "reflink=auto:"
     cp --reflink=auto $1 $2
-    md5sum $1 | _filter_testdirs
-    md5sum $2 | _filter_testdirs
+    md5sum $1 | _filter_testdir_and_scratch
+    md5sum $2 | _filter_testdir_and_scratch
 
     # always reflink, should fail outright
     rm -rf $2
@@ -86,7 +81,7 @@ _create_reflinks()
     cp --reflink=always $1 $2 >> $seqres.full 2>&1 || echo "cp reflink failed"
 
     # The failed target actually gets created by cp:
-    ls $2 | _filter_testdirs
+    ls $2 | _filter_testdir_and_scratch
 }
 
 echo "test reflinks across different devices"
diff --git a/tests/generic/409 b/tests/generic/409
index 22af44c8..3ad65c91 100755
--- a/tests/generic/409
+++ b/tests/generic/409
@@ -104,8 +104,7 @@ find_mnt()
 		    -e "s;$mpB;mpB;g" \
 		    -e "s;$mpC;mpC;g" \
 		    -e "s;$mpD;mpD;g" | \
-		_filter_spaces | _filter_scratch | \
-		_filter_test_dir | sort
+		_filter_spaces | _filter_testdir_and_scratch | sort
 	echo "======"
 }
 
diff --git a/tests/generic/410 b/tests/generic/410
index 18cb0c1c..63ab7162 100755
--- a/tests/generic/410
+++ b/tests/generic/410
@@ -110,8 +110,7 @@ find_mnt()
 		sed -e "s;$mpA;mpA;g" \
 		    -e "s;$mpB;mpB;g" \
 		    -e "s;$mpC;mpC;g" | \
-		_filter_spaces | _filter_scratch | \
-		_filter_test_dir | sort
+		_filter_spaces | _filter_testdir_and_scratch | sort
 	echo "======"
 }
 
diff --git a/tests/generic/411 b/tests/generic/411
index 5db49a44..83f6d261 100755
--- a/tests/generic/411
+++ b/tests/generic/411
@@ -93,8 +93,7 @@ find_mnt()
 		sed -e "s;$mpA;mpA;g" \
 		    -e "s;$mpB;mpB;g" \
 		    -e "s;$mpC;mpC;g" | \
-		_filter_spaces | _filter_scratch | \
-		_filter_test_dir | sort
+		_filter_spaces | _filter_testdir_and_scratch | sort
 	echo "======"
 }