Re: [PATCH linux-2.6.0-test10-mm1] filemap_fdatawait.patch

[Janet Morgan]

Andrew Morton wrote:

> Andrew Morton <akpm@xxxxxxxx> wrote:
>  
>
> > Let me actually think about this a bit.
> >    
>
> Nasty.  The same race is present in 2.4.x...
>
> How's about we start new I/O in filemap_fdatawait() if the page is dirty?
>
>
> diff -puN mm/filemap.c~a mm/filemap.c
> --- 25/mm/filemap.c~a	2003-12-31 03:10:29.000000000 -0800
> +++ 25-akpm/mm/filemap.c	2003-12-31 03:17:05.000000000 -0800
> @@ -206,7 +206,13 @@ restart:
> 		page_cache_get(page);
> 		spin_unlock(&mapping->page_lock);
>
> -		wait_on_page_writeback(page);
> +		lock_page(page);
> +		if (PageDirty(page) && mapping->a_ops->writepage) {
> +			write_one_page(page, 1);
> +		} else {
> +			wait_on_page_writeback(page);
> +			unlock_page(page);
> +		}
> 		if (PageError(page))
> 			ret = -EIO;
>
>
>  
That fixed the problem!  Stephen's testcase is running successfully on 
2.6.1-mm1 plus your patch -- no more uninitialized data!

Thanks!
-Janet
P.S. Sorry so late testing this (was on vacation).



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