diff --git a/swh/storage/db.py b/swh/storage/db.py
--- a/swh/storage/db.py
+++ b/swh/storage/db.py
@@ -197,15 +197,19 @@
         write_thread = threading.Thread(target=writer)
         write_thread.start()
 
-        with open(write_file, 'w') as f:
-            for d in items:
-                if item_cb is not None:
-                    item_cb(d)
-                line = [escape(d.get(k)) for k in columns]
-                f.write(','.join(line))
-                f.write('\n')
-
-        write_thread.join()
+        try:
+            with open(write_file, 'w') as f:
+                for d in items:
+                    if item_cb is not None:
+                        item_cb(d)
+                    line = [escape(d.get(k)) for k in columns]
+                    f.write(','.join(line))
+                    f.write('\n')
+        finally:
+            # No problem bubbling up exceptions, but we still need to make sure
+            # we finish copying, even though we're probably going to cancel the
+            # transaction.
+            write_thread.join()
 
     def mktemp(self, tblname, cur=None):
         self._cursor(cur).execute('SELECT swh_mktemp(%s)', (tblname,))
diff --git a/swh/storage/tests/test_storage.py b/swh/storage/tests/test_storage.py
--- a/swh/storage/tests/test_storage.py
+++ b/swh/storage/tests/test_storage.py
@@ -10,7 +10,7 @@
 import unittest
 from uuid import UUID
 
-from unittest.mock import patch
+from unittest.mock import Mock, patch
 
 from nose.tools import istest
 from nose.plugins.attrib import attr
@@ -2464,6 +2464,21 @@
                 },
             ])
 
+    # This test is only relevant on the local storage, with an actual
+    # objstorage raising an exception
+    @istest
+    def content_add_objstorage_exception(self):
+        self.storage.objstorage.add = Mock(
+            side_effect=Exception('mocked broken objstorage')
+        )
+
+        with self.assertRaises(Exception) as e:
+            self.storage.content_add([self.cont])
+
+        self.assertEqual(e.exception.args, ('mocked broken objstorage',))
+        missing = list(self.storage.content_missing([self.cont]))
+        self.assertEqual(missing, [self.cont['sha1']])
+
 
 class AlteringSchemaTest(BaseTestStorage, unittest.TestCase):
     """This class is dedicated for the rare case where the schema needs to