File systems, processes, circuits, devices and electronic systems

Abstract

A computer device ( 2010 ) with a file system having clusters and meta data. The computer device ( 2010 ) includes a processor ( 1030 ) and a storage ( 1025 ) coupled to the processor and having physical representations of instructions so that the processor is operable to reserve ( 230 ) at least one of the clusters and to create a log record when meta data for the file system is to be updated by a write ( 240 ) of such meta data beforehand to such a reserved cluster, and then set ( 250 ) at least one state entry to substantially represent readiness to write the meta data to the file system.

What is claimed is: 
     
         1 . An electronic system comprising:
 at least one storage holding instructions for a routine and part of the storage operable to hold files and meta data, and at least one log record having meta data and at least one state entry substantially representing a state as ready or committed; and   a processor coupled to the storage and operable according to the routine to process to the at least one state entry depending on such ready, committed, and lack thereof and to execute a response thereto.   
     
     
         2 . The electronic system claimed in  claim 1  in which, if the state entry lacks ready and lacks committed, then the response includes a write of a state datum for such a log record substantially representing a state of at least some of the meta data as discarded. 
     
     
         3 . The electronic system claimed in  claim 1  in which, in case of power failure at a point in which a state entry lacks ready and lacks committed, then the response includes a discard of meta data of the log record to which the state entry pertains. 
     
     
         4 . The electronic system claimed in  claim 1  in which the storage is operable to elsewhere hold a corresponding second state entry substantially representing the state as ready or committed. 
     
     
         5 . The electronic system claimed in  claim 4  in which the processor is operable according to the routine to access the second state entry and, if the second state entry lacks ready and lacks committed, the response includes a write of a state datum for such a log record substantially representing a state of at least some of the meta data as discarded. 
     
     
         6 . The electronic system claimed in  claim 4  in which the response includes a commit operation on a log record that is yet to be fully committed and that has a state entry substantially representing ready and the corresponding second state entry substantially represents ready, in which the commit operation includes writing meta data from the log record to elsewhere in the storage. 
     
     
         7 . The electronic system claimed in  claim 1  in which the response includes a commit operation on a log record for which the at least one state entry substantially represents readiness to write meta data from the log record to elsewhere in the storage. 
     
     
         8 . The electronic system claimed in  claim 1  in which, if a log record has a state entry substantially representing committed, the response includes retention of meta data corresponding to that log record. 
     
     
         9 . The electronic system claimed in  claim 1  in which, if a log record has a state entry substantially representing committed, the response includes a recycle operation on that log record.