Method and system of compacting sparse directories in a file system

A method of compacting sparse directories, in a file system employing a directory structure which uses a sequence of hash tables made up of blocks, with the numbers of blocks in each hash table being the numbers of blocks of its prior hash table in sequence, multiplied by two, and the blocks in each subsequent hash table comprising a lower level of blocks than the blocks in the prior hash table, and with first predetermined blocks at any level associated with second predetermined blocks at the next lower level, the method comprising:

• determining whether any first predetermined block for any hash table in the directory structure contains a number of files lower than a predetermined value;
• if it is determined for any first predetermined block that the number of files therein is lower than said predetermined value, determining if any second predetermined blocks at the next lower level contain any files therein;
• and
• if any second predetermined blocks at the next lower level contain files therein, migrating files in any second predetermined blocks into its corresponding first predetermined block or as many of the files in any second predetermined block corresponding to said first predetermined block sufficient to fill said first predetermined block.