Use of journal->j_blk_offset

[Abhishek Gupta]

Hi everyone,

So this question is more for people who are familiar with the internals of 
ext3.

I notice that the function journal_init_dev() sets the value

journal->j_blk_offset = start

This means that start can be any arbitrary block number on the device. 
However, later in the function journal_bmap() it is never actually used. 
The value of *retp in journal_bmap() is set to

*retp = blocknr; /* + journal->j_blk_offset */

A comment on the top of journal_bmap() says that the addition can be 
included in the above operation if so be the need. Is there any specific 
reason (related to performance etc) why it has not been done.

Please let me know.

Thanks

Abhishek