Re: ext4-mm-delalloc-ext4-lock-reverse-fix

[Alexey Dobriyan]

On Mon, May 19, 2008 at 05:24:47PM +0200, Jiri Slaby wrote:
> Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> > On Mon, 19 May 2008 15:15:09 +0800 "Dave Young" <hidave.darkstar@xxxxxxxxx> wrote:
> > 
> > > With 2.6.26-rc2-mm1 I need to sync frequently. It's not normal as my
> > > understanding.
> > > 
> > > 1. scp a big file from a lan server. Firstly the speed is about 8M/s,
> > > but the speed will slow down to 100K/s at last. After I exec "sync",
> > > the speed will restore.
> > > 
> > > Is this a known issue?
> > > 
> > 
> > Yes, probably related to the "mkfs takes forever" problem.  I haven't
> > looked into it yet.  Nor has anyone else afaik.
> 
> Absolutely not sure what this breaks in ext4, but fixes the problem for me:

This helps, thank you!

> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -881,7 +881,7 @@ int write_cache_pages(struct address_space *mapping,
>  	pagevec_init(&pvec, 0);
>  	if (wbc->range_cyclic) {
>  		index = mapping->writeback_index; /* Start from prev offset */
> -		end = wbc->range_end >> PAGE_CACHE_SHIFT;
> +		end = -1;
>  	} else {
>  		index = wbc->range_start >> PAGE_CACHE_SHIFT;
>  		end = wbc->range_end >> PAGE_CACHE_SHIFT;

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