From mboxrd@z Thu Jan  1 00:00:00 1970
From: "bmoon" <bo@anthologysolutions.com>
Subject: Re: How do we handle the same but uptodated data to disk cache?
Date: Wed, 28 May 2003 13:29:17 -0700
Sender: linux-raid-owner@vger.kernel.org
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To: Neil Brown <neilb@cse.unsw.edu.au>
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Help!
There must be a function which will update the data in the disk cache.
>From __make_request(), it does ordering(neighboring) the requests,
it does not deal with the same block request.

Please give me a light!

> 
> It improved a lot for the sync I/O.
> However, I am looking for a solution to handle
> the regular async I/O with a page data on the
> same sector repeatedly like writing the MD SB
> data to disk without flushing.
> 
> The follwing is my simple algorithm for it;
> 
>         bh=getblk(dev, block, size);
>         if (buffer_uptodate(bh)) { /* still in cache, not flushed yet */
>               bh->b_data = "updated data";
>               brelse(bh);
>         }
>         else { /* all were flushed or new  */
>             .
>             .
>              mark_buffer_uptodate(bh,1);
>              mark_buffer_dirty(bh);
>             generic_make_request(rw, &bh);
>        }
> 
>  Please give me your suggestion or comment.
> 

Bo