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Subject: Re: [f2fs-dev] [PATCH] f2fs: change the way of handling range.len in
 F2FS_IOC_SEC_TRIM_FILE
To:     Jaegeuk Kim <jaegeuk@kernel.org>, Daeho Jeong <daeho43@gmail.com>
CC:     Daeho Jeong <daehojeong@google.com>, <kernel-team@android.com>,
        <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>
References: <20200710021505.2405872-1-daeho43@gmail.com>
 <20200710030246.GA545837@google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <62c9dd7a-5d18-8bb6-8e43-c055fcff51cc@huawei.com>
Date:   Fri, 10 Jul 2020 11:21:55 +0800
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On 2020/7/10 11:02, Jaegeuk Kim wrote:
> On 07/10, Daeho Jeong wrote:
>> From: Daeho Jeong <daehojeong@google.com>
>>
>> Changed the way of handling range.len of F2FS_IOC_SEC_TRIM_FILE.
>>  1. Added -1 value support for range.len to signify the end of file.
>>  2. If the end of the range passes over the end of file, it means until
>>     the end of file.
>>  3. ignored the case of that range.len is zero to prevent the function
>>     from making end_addr zero and triggering different behaviour of
>>     the function.
>>
>> Signed-off-by: Daeho Jeong <daehojeong@google.com>
>> ---
>>  fs/f2fs/file.c | 16 +++++++---------
>>  1 file changed, 7 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>> index 368c80f8e2a1..1c4601f99326 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -3813,21 +3813,19 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
>>  	file_start_write(filp);
>>  	inode_lock(inode);
>>  
>> -	if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode)) {
>> +	if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode) ||
>> +			range.start >= inode->i_size) {
>>  		ret = -EINVAL;
>>  		goto err;
>>  	}
>>  
>> -	if (range.start >= inode->i_size) {
>> -		ret = -EINVAL;
>> +	if (range.len == 0)
>>  		goto err;
>> -	}
>>  
>> -	if (inode->i_size - range.start < range.len) {
>> -		ret = -E2BIG;
>> -		goto err;
>> -	}
>> -	end_addr = range.start + range.len;
>> +	if (range.len == (u64)-1 || inode->i_size - range.start < range.len)
>> +		end_addr = inode->i_size;

We can remove 'range.len == (u64)-1' condition since later condition can cover
this?

> 
> Hmm, what if there are blocks beyond i_size? Do we need to check i_blocks for

The blocks beyond i_size will never be written, there won't be any valid message
there, so we don't need to worry about that.

Thanks,

> ending criteria?
> 
>> +	else
>> +		end_addr = range.start + range.len;
>>  
>>  	to_end = (end_addr == inode->i_size);
>>  	if (!IS_ALIGNED(range.start, F2FS_BLKSIZE) ||
>> -- 
>> 2.27.0.383.g050319c2ae-goog
>>
>>
>>
>> _______________________________________________
>> Linux-f2fs-devel mailing list
>> Linux-f2fs-devel@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> 
> 
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