From eeae78fbf2c431b3db59c55b8c8f5868b48f01f1 Mon Sep 17 00:00:00 2001
From: Eliot Horowitz <eliot@10gen.com>
Date: Fri, 12 Feb 2010 14:07:17 -0500
Subject: [PATCH] when creating a DB for the first time, and only need a read
 lock, make sure to give up the write lock

---
 db/client.cpp | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/db/client.cpp b/db/client.cpp
index 2d390f4cd68..a01826f8b85 100644
--- a/db/client.cpp
+++ b/db/client.cpp
@@ -110,12 +110,26 @@ namespace mongo {
             _justCreated = false;
         }
         else {
-            // we need to be in a write lock since we're going to create the DB object
-            if ( _lock )
-                _lock->releaseAndWriteLock();
-            assertInWriteLock();
+            for ( int x=0; x<2; x++ ){
+                { //   we need to be in a write lock since we're going to create the DB object
+                    // to do that, we're going to unlock, then get a write lock
+                    // this is so that if this is the first query and its long doesn't block db
+                    // we just have to check that the db wasn't closed in the interim where we unlock
+                    
+                    dbtemprelease unlock;
+                    writelock lk( _ns );
+                    dbHolder.getOrCreate( _ns , _path , _justCreated );
+                }
+                
+                _db = dbHolder.get( _ns , _path );
+                
+                if ( _db )
+                    break;
+                
+                log() << "db was closed on us right after we opened it: " << _ns << endl;
+            }
             
-            _db = dbHolder.getOrCreate( _ns , _path , _justCreated );
+            uassert( 13005 , "can't create db, keeps getting closed" , _db );
         }
         
         _client->_context = this;