diff --git a/newsfragments/3411.minor b/newsfragments/3411.minor
new file mode 100644
index 000000000..e69de29bb
diff --git a/src/allmydata/storage/common.py b/src/allmydata/storage/common.py
index 55036eea7..cb6116e5b 100644
--- a/src/allmydata/storage/common.py
+++ b/src/allmydata/storage/common.py
@@ -1,4 +1,14 @@
-from future.utils import PY3
+"""
+Ported to Python 3.
+"""
+from __future__ import unicode_literals
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from future.utils import PY2, PY3
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 import os.path
 from allmydata.util import base32
diff --git a/src/allmydata/storage/lease.py b/src/allmydata/storage/lease.py
index 4d2dce8c4..187f32406 100644
--- a/src/allmydata/storage/lease.py
+++ b/src/allmydata/storage/lease.py
@@ -1,3 +1,16 @@
+"""
+Ported to Python 3.
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
+
 import struct, time
 
 class LeaseInfo(object):
diff --git a/src/allmydata/storage/mutable.py b/src/allmydata/storage/mutable.py
index a1eddf6cc..a44a2e18d 100644
--- a/src/allmydata/storage/mutable.py
+++ b/src/allmydata/storage/mutable.py
@@ -1,3 +1,16 @@
+"""
+Ported to Python 3.
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+from __future__ import unicode_literals
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
+
 import os, stat, struct
 
 from allmydata.interfaces import BadWriteEnablerError
diff --git a/src/allmydata/storage/shares.py b/src/allmydata/storage/shares.py
index bd94c0f3f..ec6c0a501 100644
--- a/src/allmydata/storage/shares.py
+++ b/src/allmydata/storage/shares.py
@@ -1,4 +1,15 @@
-#! /usr/bin/python
+"""
+Ported to Python 3.
+"""
+
+from __future__ import unicode_literals
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from future.utils import PY2
+if PY2:
+    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 from allmydata.storage.mutable import MutableShareFile
 from allmydata.storage.immutable import ShareFile
diff --git a/src/allmydata/test/test_storage.py b/src/allmydata/test/test_storage.py
index 4bbbcda30..8956fbf52 100644
--- a/src/allmydata/test/test_storage.py
+++ b/src/allmydata/test/test_storage.py
@@ -29,10 +29,12 @@ import itertools
 from allmydata import interfaces
 from allmydata.util import fileutil, hashutil, base32
 from allmydata.storage.server import StorageServer
+from allmydata.storage.shares import get_share_file
 from allmydata.storage.mutable import MutableShareFile
-from allmydata.storage.immutable import BucketWriter, BucketReader
+from allmydata.storage.immutable import BucketWriter, BucketReader, ShareFile
 from allmydata.storage.common import DataTooLargeError, storage_index_to_dir, \
-     UnknownMutableContainerVersionError, UnknownImmutableContainerVersionError
+     UnknownMutableContainerVersionError, UnknownImmutableContainerVersionError, \
+     si_b2a, si_a2b
 from allmydata.storage.lease import LeaseInfo
 from allmydata.immutable.layout import WriteBucketProxy, WriteBucketProxy_v2, \
      ReadBucketProxy
@@ -52,6 +54,42 @@ from allmydata.storage_client import (
 from .common_py3 import FakeCanary, LoggingServiceParent, ShouldFailMixin
 
 
+class UtilTests(unittest.TestCase):
+    """Tests for allmydata.storage.common and .shares."""
+
+    def test_encoding(self):
+        """b2a/a2b are the same as base32."""
+        s = b"\xFF HELLO \xF3"
+        result = si_b2a(s)
+        self.assertEqual(base32.b2a(s), result)
+        self.assertEqual(si_a2b(result), s)
+
+    def test_storage_index_to_dir(self):
+        """storage_index_to_dir creates a native string path."""
+        s = b"\xFF HELLO \xF3"
+        path = storage_index_to_dir(s)
+        parts = os.path.split(path)
+        self.assertEqual(parts[0], parts[1][:2])
+        self.assertIsInstance(path, native_str)
+
+    def test_get_share_file_mutable(self):
+        """A mutable share is identified by get_share_file()."""
+        path = self.mktemp()
+        msf = MutableShareFile(path)
+        msf.create(b"12", b"abc")  # arbitrary values
+        loaded = get_share_file(path)
+        self.assertIsInstance(loaded, MutableShareFile)
+        self.assertEqual(loaded.home, path)
+
+    def test_get_share_file_immutable(self):
+        """An immutable share is identified by get_share_file()."""
+        path = self.mktemp()
+        _ = ShareFile(path, max_size=1000, create=True)
+        loaded = get_share_file(path)
+        self.assertIsInstance(loaded, ShareFile)
+        self.assertEqual(loaded.home, path)
+
+
 class FakeStatsProvider(object):
     def count(self, name, delta=1):
         pass
diff --git a/src/allmydata/util/_python3.py b/src/allmydata/util/_python3.py
index afdbea1f0..2b10854a9 100644
--- a/src/allmydata/util/_python3.py
+++ b/src/allmydata/util/_python3.py
@@ -35,8 +35,12 @@ PORTED_MODULES = [
     "allmydata.immutable.happiness_upload",
     "allmydata.interfaces",
     "allmydata.monitor",
+    "allmydata.storage.common",
     "allmydata.storage.crawler",
     "allmydata.storage.expirer",
+    "allmydata.storage.lease",
+    "allmydata.storage.mutable",
+    "allmydata.storage.shares",
     "allmydata.test.common_py3",
     "allmydata.uri",
     "allmydata.util._python3",