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Subject: Re: [PATCH 18/25] btrfs: Use readahead_batch_length
To:     Matthew Wilcox <willy@infradead.org>
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        <linux-kernel@vger.kernel.org>
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From:   John Hubbard <jhubbard@nvidia.com>
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On 12/17/20 5:42 AM, Matthew Wilcox wrote:
> On Thu, Dec 17, 2020 at 12:12:46PM +0000, Matthew Wilcox wrote:
>> ehh ... probably an off-by-one.  Does subtracting 1 from contig_end fix it?
>> I'll spool up a test VM shortly and try it out.
> 
> Yes, this fixed it:
> 
> -               u64 contig_end = contig_start + readahead_batch_length(rac);
> +               u64 contig_end = contig_start + readahead_batch_length(rac) - 1;
> 

Yes, confirmed on my end, too.

thanks,
-- 
John Hubbard
NVIDIA