So I was able to create a new WRITE command that got run with a read lock and did an insert without asserting. Presumably a lockType=WRITE/requiresAuth=false combo is unusual. There are a couple such commands right now, but I think they would more properly have read locks. Might be worth putting a guard in execCommand() anyway.

struct BogusCmd : public Command {
BogusCmd() : Command( "bogus" ){}
virtual bool slaveOk()

{ return true; }

virtual LockType locktype()

{ return WRITE; }

virtual bool requiresAuth()

{ return false; }

virtual bool run(const char * badns, BSONObj& cmdObj, string& errmsg, BSONObjBuilder& result, bool)

{ log() << "mutex state: " << dbMutex.getState() << endl; BSONObj o = BSON( "a" << "b" ); theDataFileMgr.insert( "test.test", o ); return true; }

} bogusCommand;