From mboxrd@z Thu Jan  1 00:00:00 1970
From: Miao Xie <miaox@cn.fujitsu.com>
Subject: Re: [PATCH 7/7] btrfs: fix a wrong error check in add_ra_bio_pages()
Date: Thu, 29 Jul 2010 18:47:16 +0800
Message-ID: <4C515C34.9090005@cn.fujitsu.com>
References: <4C513C95.3080403@cn.fujitsu.com> <AANLkTim+U2s5-vHhmPqam9wj0+0_=01bq3JjnR=xB8T2@mail.gmail.com>
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Cc: Chris Mason <chris.mason@oracle.com>,
	Linux Btrfs <linux-btrfs@vger.kernel.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>
To: "Yan, Zheng" <zheng.yan@oracle.com>
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On Thu, 29 Jul 2010 18:38:39 +0800, Yan, Zheng wrote:
> 2010/7/29 Miao Xie<miaox@cn.fujitsu.com>:
>> From: Liu Bo<liubo2009@cn.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@cn.fujitsu.com>
>> Signed-off-by: Miao Xie<miaox@cn.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
>
>