mkdir (): Permission denied

I'm trying to create a directory through PHP on my local Linux server, but I'm not getting it. It gives the following error:

mkdir(): Permission denied...

I have tried the following codes:

if(!file_exists($diretorio)){
          mkdir("/../../".$ano,0777,true);
 }

and that too:

if(!file_exists($diretorio)){
          mkdir("/../../".$ano);
          chmod("../../".$ano,0777);
 }

and by disenchantment of conscience:

if(!file_exists($diretorio)){
          mkdir("/../../".$ano,0777,true);
          chmod("../../".$ano,0777);
 }

but all return that error. The root directory is 777. Does anyone know how I can resolve this?