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Subject: Re: [PATCH] f2fs: compress: fix to disallow enabling compress on
 non-empty file
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>, <chao@kernel.org>
References: <20200918030349.19667-1-yuchao0@huawei.com>
 <20200924200305.GA2568648@google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <dbf3a532-cd38-2b31-e4ab-e83505c6c9c4@huawei.com>
Date:   Fri, 25 Sep 2020 08:57:15 +0800
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On 2020/9/25 4:03, Jaegeuk Kim wrote:
> On 09/18, Chao Yu wrote:
>> Compressed inode and normal inode has different layout, so we should
>> disallow enabling compress on non-empty file to avoid race condition
>> during inode .i_addr array parsing and updating.
>>
>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>> ---
>>   fs/f2fs/file.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index 58e464cc15f0..139fdfc1dc55 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -1821,6 +1821,8 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
>>   		if (iflags & F2FS_COMPR_FL) {
>>   			if (!f2fs_may_compress(inode))
>>   				return -EINVAL;
>> +			if (inode->i_size)
> 
> Changed like this.
> 
> +                       if (S_ISREG(inode->i_mode) && inode->i_size)

My bad, thanks for fixing this. :)

Thanks,

> 
> 
>> +				return -EINVAL;
>>   
>>   			set_compress_context(inode);
>>   		}
>> -- 
>> 2.26.2
> .
>