wrap dbtests with a big dblcok - now passes

1 files changed, 8 insertions, 0 deletions

diff --git a/db/instance.h b/db/instance.h
index fdd572730ae..83d016ad560 100644
--- a/db/instance.h
+++ b/db/instance.h
@@ -139,6 +139,14 @@ namespace mongo {
             SavedContext() {
                 Client *c = currentClient.get();
                 if ( c->database() ) {
+                    /* note you must already be locked here or the database pointer could 
+                    be garbage as the db may have been dropped. there are definitely places 
+                    in the code where we are done with a db post setClient() and usage
+                    and left the pointer set.  if you called SavedContext thereafter unlocked,
+                    that is unsafe, although the code was doing it for a long time. 
+                    Thus this assert is required. Ideally context would be nulled out when 
+                    done so we never have this problem.
+                    */
                     dbMutex.assertAtLeastReadLocked();
                     _oldName = c->database()->name;
                 }