linux-kernel - Re: [PATCH 7/7] btrfs: fix a wrong error check in add_ra_bio

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Date:	Thu, 29 Jul 2010 18:47:16 +0800
From:	Miao Xie <miaox@...fujitsu.com>
To:	"Yan, Zheng" <zheng.yan@...cle.com>
CC:	Chris Mason <chris.mason@...cle.com>,
	Linux Btrfs <linux-btrfs@...r.kernel.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 7/7] btrfs: fix a wrong error check in add_ra_bio_pages()

On Thu, 29 Jul 2010 18:38:39 +0800, Yan, Zheng wrote:
> 2010/7/29 Miao Xie<miaox@...fujitsu.com>:
>> From: Liu Bo<liubo2009@...fujitsu.com>
>>
>> Only when a page is not found by page_index, we'll go to the error check.
>>
>> Signed-off-by: Liu Bo<liubo2009@...fujitsu.com>
>> Signed-off-by: Miao Xie<miaox@...fujitsu.com>
>> ---
>>   fs/btrfs/compression.c |    2 +-
>>   1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
>> index cb3877c..8458840 100644
>> --- a/fs/btrfs/compression.c
>> +++ b/fs/btrfs/compression.c
>> @@ -467,7 +467,7 @@ static noinline int add_ra_bio_pages(struct inode *inode,
>>                 rcu_read_lock();
>>                 page = radix_tree_lookup(&mapping->page_tree, page_index);
>>                 rcu_read_unlock();
>> -               if (page) {
>> +               if (!page) {
>>   check_misses:
>>                         misses++;
>>                         if (misses>  4)
>
> This patch is wrong. The word "miss" here means "miss for read-ahead because
> the page is already in the page cache"

Oh, my mistake. Sorry!
Please ignore this patch.

Thanks for your review! How about the others?
Miao

>
> Yan, Zheng
>
>

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