SERVER-16923 Create the system.profile collection if under DB X lock

2 files changed, 11 insertions, 7 deletions

diff --git a/src/mongo/db/catalog/database_holder.cpp b/src/mongo/db/catalog/database_holder.cpp
index 83006f7d60e..5fca8d11c71 100644
--- a/src/mongo/db/catalog/database_holder.cpp
+++ b/src/mongo/db/catalog/database_holder.cpp
@@ -136,12 +136,13 @@ namespace {
             *justCreated = !exists;
         }
 
-        // Only one thread can be inside this method for the same DB name, because of the
-        // requirement for X-lock on the database. So there is no way we can insert two different
-        // databases for the same name.
-        SimpleMutex::scoped_lock lk(_m);
-
+        // Do this outside of the scoped lock, because database creation does transactional
+        // operations which may block. Only one thread can be inside this method for the same DB
+        // name, because of the requirement for X-lock on the database when we enter. So there is
+        // no way we can insert two different databases for the same name.
         db = new Database(txn, dbname, entry);
+
+        SimpleMutex::scoped_lock lk(_m);
         _dbs[dbname] = db;
 
         return db;
diff --git a/src/mongo/db/introspect.cpp b/src/mongo/db/introspect.cpp
index f90dec52159..a43e92edc66 100644
--- a/src/mongo/db/introspect.cpp
+++ b/src/mongo/db/introspect.cpp
@@ -94,7 +94,9 @@ namespace {
         AuthorizationSession * authSession = txn->getClient()->getAuthorizationSession();
         _appendUserInfo(*txn->getCurOp(), b, authSession);
 
-        BSONObj p = b.done();
+        const BSONObj p = b.done();
+
+        const bool wasLocked = txn->lockState()->isLocked();
 
         const string dbName(nsToDatabase(txn->getCurOp()->getNS()));
 
@@ -132,7 +134,8 @@ namespace {
 
                     break;
                 }
-                else if (!acquireDbXLock && !txn->lockState()->isLocked()) {
+                else if (!acquireDbXLock &&
+                            (!wasLocked || txn->lockState()->isDbLockedForMode(dbName, MODE_X))) {
                     // Try to create the collection only if we are not under lock, in order to
                     // avoid deadlocks due to lock conversion. This would only be hit if someone
                     // deletes the profiler collection after setting profile level.