Re: [RFC][PATCH] mm: write_cache_pages be more sequential

From: Artem Bityutskiy
Date: Mon Sep 14 2009 - 11:45:45 EST


On Mon, 2009-09-07 at 17:07 +0300, Adrian Hunter wrote:
> From 6f3bb7c26936c45d810048f59c369e8d5a5623fc Mon Sep 17 00:00:00 2001
> From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Date: Mon, 7 Sep 2009 10:49:11 +0300
> Subject: [PATCH] mm: write_cache_pages be more sequential
>
> If a file is written to sequentially, then writeback
> should write the pages sequentially also. However,
> that does not always happen. For example:
>
> 1) user writes pages 0, 1 and 2 but 2 is incomplete
> 2) write_cache_pages writes pages 0, 1 and 2 and sets
> writeback_index to 3
> 3) user finishes writing page 2 and writes pages 3 and 4
> 4) write_cache_pages writes pages 3 and 4, and then cycles
> back and writes page 2 again.
>
> So the pages are written out in the order 0, 1, 2, 3 ,4 ,2
> instead of 0, 1, 2, 2, 3, 4.
>
> This situation was noticed on UBIFS because it writes
> directly from writepage. Hence if there is an unexpected
> power-loss, a file will end up with a hole even though
> the file was written sequentially by the user.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

I wonder, who would merge this patch?

--
Best Regards,
Artem Bityutskiy (ÐÑÑÑÐ ÐÐÑÑÑÐÐÐ)

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