On Fri, Jul 22, 2016 at 3:05 PM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote:
> On Fri, Jul 22, 2016 at 5:36 AM, Thomas Gambier
> <thomas.gambier@xxxxxxxxx> wrote:
>> Hello,
>>
>> when doing more tests with TCL, I found a more critical problem.
>>
>> If I create a directory and just after I create a read only file (mode
>> 0444) inside it, I got a permission denied error. See the attached C
>> source code. As the previous error, it is random but I always have it
>> fail before the 10th execution.
>>
>> I attach the network traffic but it seems that the problem is again in
>> the client.
>>
>> Olga, could you test this new testcase on the newest kernel ?
>
> Works fine for me on the RHEL7.2 and upstream.
>
This is strange because I just tested on CentOS7.2 (my kernel is
3.10.0-327.el7.x86_64) and I have the problem.
>>
>> Regards.
>>
>> Thomas.
>>
>> On Thu, Jul 21, 2016 at 8:10 PM, Olga Kornievskaia <aglo@xxxxxxxxx> wrote:
>>> On Thu, Jul 21, 2016 at 1:14 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>>>> On Thu, Jul 21, 2016 at 04:54:36PM +0200, Thomas Gambier wrote:
>>>>> On Mon, Jul 18, 2016 at 4:09 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>>>>> > On Mon, Jul 18, 2016 at 03:44:48PM +0200, Thomas Gambier wrote:
>>>>> >> Hello,
>>>>> >>
>>>>> >> thanks for your answer. See my comments below.
>>>>> >>
>>>>> >> On Wed, Jul 13, 2016 at 3:26 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>>>>> >> > On Mon, Jul 11, 2016 at 07:40:11PM +0200, Thomas Gambier wrote:
>>>>> >> >> Hello,
>>>>> >> >>
>>>>> >> >> I just discovered a problem with NFSv4 file system. I was using TCL
>>>>> >> >> scripts that were doing some file manipulation (mkdir, copy, ...) on
>>>>> >> >> my NFSv4 file system and sometimes the scripts failed with "permission
>>>>> >> >> denied" error.
>>>>> >> >>
>>>>> >> >> I ran strace and I found that the system call returning the error was:
>>>>> >> >> open("d1/in.txt", O_WRONLY|O_CREAT|O_TRUNC, 0100444) = -1 EACCES
>>>>> >> >> (Permission denied)
>>>>> >> >
>>>>> >> > Is that even allowed? The open(2) man page says posix leaves behavior
>>>>> >> > in that case unspecified, and doesn't say anything I can find about
>>>>> >> > Linux behavior in this case.
>>>>> >> >
>>>>> >> You're right. I will send a mail to TCL mailing list to know why they
>>>>> >> put this flag in the open call.
>>>>> >>
>>>>> >> > I guess it would be nicer for client or server to do something
>>>>> >> > predictable, though. First steps might be to confirm what happens other
>>>>> >> > filesystems, then do a network trace (watch the traffic in wireshark) to
>>>>> >> > see if it's the client rejecting this open, or the client passing
>>>>> >> > through that bit in the mode and the server returning the error.
>>>>> >>
>>>>> >> I agree. For other filesystem, I only tested with ext4 which works
>>>>> >> fine. Let me know if you want me to test specific filesystems.
>>>>> >>
>>>>> >> I attach the wireshark capture of a test with 8 open call working fine
>>>>> >> and the 9th one failing. For me, it seems the activity on the network
>>>>> >> is exactly the same for the failing case (same call from client to
>>>>> >> server and same answer from server to client). It would mean that the
>>>>> >> client itself is messing things up...
>>>>> >
>>>>> > Agreed, sounds like the client's only deciding to fail the open after
>>>>> > the OPEN call to the server succeeds.
>>>>> >
>>>>> > Unfortunately, the client open logic is (necessarily) pretty
>>>>> > complicated--a few minutes digging around wasn't enough for me to figure
>>>>> > uot where the error's coming from.
>>>>> >
>>>>>
>>>>> I'm not sure if I can help... I don't know the NFS source code at all.
>>>>> I can do more tests if you need, though.
>>>>
>>>> It doesn't look like a high priority based just on what we know
>>>> (slightly odd behavior in an undefined case), so I think we'll just have
>>>> to leave it at that until somebody gets curious. Thanks for the report.
>>>>
>>>
>>> Hi Thomas,
>>>
>>> I don't know exactly what was fixed or when but I thought I'd note
>>> that I don't see the problem on the upstream 4.7-rc7 but I can
>>> reproduce the problem on RHEL7.2 kernel.
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