1. A method of operating a primary data processor and a secondary data processor for access to a file system in data storage, said method comprising: the primary data processor pre-allocating data blocks of the data storage to the file system before the pre-allocated data blocks are needed for extending the file system, and the secondary data processor using at least some of the pre-allocated data blocks for extending the file system, wherein said method further includes selecting an address mapping for said at least some of the pre-allocated blocks in order to reduce block scatter on disk and improve I/O performance.