RFR 4823133: RandomAccessFile.length() is not thread-safe

[Dmitry Samersoff]

Vyom,

I did some tests and the problem mentioned below is not relevant to
Java. I can't reproduce it with Java testcase.

Sorry for a noise.

-Dmitry

On 2015-12-18 23:42, vyom wrote:
> Hi Dmitry,
> 
> thanks for the review can you please explain little bit more, as per my
> testing and implementation i did not found any differences with fix and
> without fix. Even i checked the java.io.File.length() and there also it
> looks like we are using stat64().
> 
> as per you mail i truncate the file and with and without fix length is
> 102400, can you please explain little bit more about the problem that
> you mention it will be help full for me to debug further.
> 
> Thanks,
> Vyom
> 
> 
> On Friday 18 December 2015 05:35 PM, Dmitry Samersoff wrote:
>> Vyom,
>>
>> If I read the changes correctly, current code returns result of lseek()
>> but your code returns result of fstat().
>>
>> I'm not sure it's a correct replacement.
>>
>>
>> dooku:test#truncate --size=102400 test.me
>>
>> dooku:test#./test
>> STAT: 102400 0 Success
>> SEEK: 2 0 Success
>>
>> Moreover, if you truncate a file to value that large than available free
>> space, lseek returns appropriate error but stat - not.
>>
>> -Dmitry
>>
>>
>>
>> On 2015-12-16 11:56, vyom wrote:
>>> Hi All,
>>>
>>> Please find the updated
>>> webrev(http://cr.openjdk.java.net/~vtewari/4823133/webrev0.1/
>>> <http://cr.openjdk.java.net/%7Evtewari/4823133/webrev0.1/>). I
>>> incorporated the review comments by Roger Riggs.
>>>
>>> Thanks,
>>> Vyom
>>>
>>>
>>> On Tuesday 15 December 2015 10:01 PM, Roger Riggs wrote:
>>>> Hi Yvom,
>>>>
>>>> Minor comments:
>>>>
>>>> src/java.base/share/native/libjava/RandomAccessFile.c:
>>>>   - "length fail" might be clearer as "GetLength failed"
>>>>
>>>> src/java.base/unix/native/libjava/io_util_md.c:
>>>>
>>>>   - Please add a comment before the define of FILE_OFFSET_BITS to
>>>> indicate where it is used and why it is there.
>>>>   - BTW, are there any unintended side effects?
>>>>     Perhaps a different issue but perhaps 64 bit offsets should be used
>>>> everywhere
>>>>
>>>> src/java.base/windows/native/libjava/io_util_md.c
>>>>   - Line 592: Using INVALID_HANDLE_VALUE is better than -1 and is used
>>>> elsewhere in the file
>>>>     BTW, Testing for invalid handle might be unnecessary since the call
>>>> to GetFileSizeEx will fail
>>>>     if it is invalid, yielding the same result.
>>>>
>>>> Roger
>>>>
>>>> On 12/10/2015 5:52 AM, vyom wrote:
>>>>> Hi All,
>>>>>
>>>>> Please review my changes for below bug.
>>>>>
>>>>> Bug: JDK-4823133 : RandomAccessFile.length() is not thread-safe
>>>>>
>>>>> Webrev:http://cr.openjdk.java.net/~vtewari/4823133/webrev0.0/
>>>>> <http://cr.openjdk.java.net/%7Evtewari/4823133/webrev0.0/>
>>>>>
>>>>> This change ensure that  length() does not temporarily changes the
>>>>> file pointer and it will make sure that there is no race
>>>>> condition in case of multi thread uses.
>>>>>
>>>>> Thanks,
>>>>> Vyom
>>>>>
>>>>>
>>>>>
>>>>>
>>
> 


-- 
Dmitry Samersoff
Oracle Java development team, Saint Petersburg, Russia
* I would love to change the world, but they won't give me the sources.