SERVER-2737 commitIfNeeded() in cappedTruncateAfter()

db/cap.cpp

@@ -319,6 +319,7 @@ namespace mongo {
                 // 'end' has been found and removed, so break.
                 break;
             }
+            getDur().commitIfNeeded();
             // 'curr' will point to the newest document in the collection.
             DiskLoc curr = theCapExtent()->lastRecord;
             assert( !curr.isNull() );

jstests/slowWeekly/rollback4.js

@@ -0,0 +1,50 @@
+// Test a large rollback SERVER-2737
+
+var replTest = new ReplSetTest({ name: 'unicomplex', nodes: 3, oplogSize: 2000 });
+var nodes = replTest.nodeList();
+
+var conns = replTest.startSet();
+var r = replTest.initiate({ "_id": "unicomplex",
+                          "members": [
+                                      { "_id": 0, "host": nodes[0] },
+                                      { "_id": 1, "host": nodes[1] },
+                                      { "_id": 2, "host": nodes[2], arbiterOnly: true}]
+                          });
+
+// Make sure we have a master
+var master = replTest.getMaster();
+b_conn = conns[1];
+b_conn.setSlaveOk();
+B = b_conn.getDB("admin");
+
+// Make sure we have an arbiter
+assert.soon(function () {
+            res = conns[2].getDB("admin").runCommand({ replSetGetStatus: 1 });
+            return res.myState == 7;
+            }, "Arbiter failed to initialize.");
+
+// Wait for initial replication
+replTest.awaitReplication();
+
+// Insert into master
+var big = { b:new Array( 1000 ).toString() };
+for( var i = 0; i < 1000000; ++i ) {
+    if ( i % 10000 == 0 ) {
+        print( i );
+    }
+	master.getDB( 'db' ).c.insert( big );
+}
+
+// Stop master
+replTest.stop( 0 );
+
+// Wait for slave to take over
+assert.soon(function () { return B.isMaster().ismaster; });
+master = replTest.getMaster();
+
+// Save to new master, forcing rollback of old master
+master.getDB( 'db' ).c.save( big );
+
+// Restart old master
+replTest.restart( 0 );
+replTest.awaitReplication();