Re: [Patch 1/4] fs.h: b_journal_head

[Nathan Scott <nathans@sgi.com>]

Hi Joe,

On Tue, Dec 09, 2003 at 12:24:18PM +0000, Joe Thornber wrote:
> Add a new member to struct buffer_head called b_journal_head.  This is
> for jbd to use, rather than have it peeking at b_private for in flight
> ios.
> ...
> --- diff/include/linux/fs.h	2003-12-09 10:25:27.000000000 +0000
> +++ source/include/linux/fs.h	2003-12-09 10:32:41.000000000 +0000
> @@ -265,7 +265,7 @@
>  	struct page *b_page;		/* the page this bh is mapped to */
>  	void (*b_end_io)(struct buffer_head *bh, int uptodate); /* I/O completion */
>   	void *b_private;		/* reserved for b_end_io */
> -
> + 	void *b_journal_head;		/* ext3 journal_heads */
>  	unsigned long b_rsector;	/* Real buffer location on disk */
>  	wait_queue_head_t b_wait;
>  

Could you explain a bit more about when b_private should and
shouldn't be used with this change?  We make use of b_private
within XFS, I'm just wondering if we will be stepping on each
others toes here?  And if XFS does need to use b_journal_head
instead of b_private with DM, maybe a more generic name like
"b_fsprivate" or something would be clearer?

thanks.

-- 
Nathan