[Ocfs2-devel] [PATCH] ocfs2: llseek need to inode cluster lock and unlock for update the inode size in SEEK_END.

[shencanquan <shencanquan@huawei.com>]

On 2013/6/17 23:17, Jeff Liu wrote:

> On 06/17/2013 10:48 PM, shencanquan wrote:
> 
>> We found that llseek has a bug when in SEEK_END.  it need to add the 
>> inode lock and unlock.
>> This bug can be reproduce the following scenario:
>> On one nodeA, open the file and then write some data to file and close 
>> the file .
>> On another nodeB , open the file and llseek the end of file . the 
>> position of file is old.
> 
> Can you please wrap these around 72 columns or so in the future?
> Also, that would be appreciated if you can supply more detailed
> info to reflect the results before/after applying this patch.
> 

 Thanks for your comments.

>>
>> Signed-off-by: jensen <shencanquan@huawei.com>
>> ---
>>   file.c |    7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/file.c b/file.c
>> index ff54014..4ee7c80 100644
>> --- a/file.c
>> +++ b/file.c
>> @@ -2626,6 +2626,13 @@ static loff_t ocfs2_file_llseek(struct file 
>> *file, loff_t offset, int whence)
>>       case SEEK_SET:
>>           break;
>>       case SEEK_END:
>> +        /*need to inode lock and unlock for update the inode size.*/
> 
> Please add spaces between comments and annotation, i.e,

> 	   /*  Need to ...... */
> 
>> +        ret = ocfs2_inode_lock(inode, NULL, 0);
>> +        if (ret < 0) {
>> +            mlog_errno(ret);
>> +            goto out;
>> +        }
>> +        ocfs2_inode_unlock(inode, 0);
>>           offset += inode->i_size;
> 
> Why not protect the offset adjustment insides ocfs2 inode locks?

yes. it need to protect the offset adjustment.

> 
>>           break;
>>       case SEEK_CUR:
> 
> Looks your email client has not configured properly for posting patches
> because all those changes are not using tab for code indentation, please
> refer to Documentation/email-clients.txt for detail if so.

Thanks you. I will see the document .

> 
> -Jeff
> 
>