Forum: Ruby-core [ruby-trunk - Bug #7109][Open] File.utime doesn't set nanoseconds

Issue #7109 has been reported by bkabrda (Bohuslav Kabrda).

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Bug #7109: File.utime doesn't set nanoseconds
https://bugs.ruby-lang.org/issues/7109

Author: bkabrda (Bohuslav Kabrda)
Status: Open
Priority: Normal
Assignee:
Category:
Target version:
ruby -v: ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]


Hi,
I'm having a problem with File.utime on RHEL 5/CentOS 5. The File.utime 
method seems not to set nanoseconds properly, see the attached test 
case, that fails (the nanoseconds get rounded to thousand, so in fact I 
get microseconds). The test doesn't seem to fail on newer platforms with 
the same Ruby version, though (RHEL 6/CentOS 6, Fedora 17). Note, that 
when creating/modifying files, the nanoseconds get set and are returned 
properly, so it seems that they are supported by filesystem.

Sample failure:
  1) Failure:
test_utime(TestUtime) 
[/builddir/build/BUILD/rubygem-sprockets-2.4.5/opt/rh/ruby193/root/usr/share/gems/gems/sprockets-2.4.5/file_utime_fail.rb:10]:
Expected: 391199303
  Actual: 391199000

Any idea what might be wrong?
Thanks!

2012/10/5 bkabrda (Bohuslav Kabrda) <bkabrda@redhat.com>:

> I'm having a problem with File.utime on RHEL 5/CentOS 5. The File.utime method 
seems not to set nanoseconds properly, see the attached test case, that fails (the 
nanoseconds get rounded to thousand, so in fact I get microseconds). The test 
doesn't seem to fail on newer platforms with the same Ruby version, though (RHEL 
6/CentOS 6, Fedora 17). Note, that when creating/modifying files, the nanoseconds 
get set and are returned properly, so it seems that they are supported by 
filesystem.

utimensat system call is required to set nanosecond filestamp.
It is available since Linux 2.6.22.
(glibc support is also required but I'm not sure the exact version.)

I guess RHEL 5/CentOS 5 is older than that.

----- Original Message -----
>
> utimensat system call is required to set nanosecond filestamp.
> It is available since Linux 2.6.22.
> (glibc support is also required but I'm not sure the exact version.)
>
> I guess RHEL 5/CentOS 5 is older than that.
> --
> Tanaka Akira
>
>

True, kernel version is 2.6.19. So is there another way to solve this or 
do I have to get along with microseconds?

Thanks.

2012/10/5 Bohuslav Kabrda <bkabrda@redhat.com>:

> True, kernel version is 2.6.19. So is there another way to solve this or do I 
have to get along with microseconds?

We can't set a timestamp without appropriate system call.

>> utimensat system call is required to set nanosecond filestamp.
>> It is available since Linux 2.6.22.
>> (glibc support is also required but I'm not sure the exact version.)
>>
>> I guess RHEL 5/CentOS 5 is older than that.
>
> True, kernel version is 2.6.19. So is there another way to solve this or do I 
have to get along with microseconds?

No another way. This is kernel limitation. In other word, you can't
compare gettimeofday() result and stat() result straightforwardly.

btw, even tough you use RHEL6, you can see this issue if you use some
older filesystems.
it depend on filesystem.

btw2, http://en.wikipedia.org/wiki/Ext4 says nanosecond timestamp is a
new feature of ext4.
I suspect your "RHEL5" mean ext3.

Issue #7109 has been updated by mame (Yusuke Endoh).

Status changed from Open to Rejected

It cannot be avoided because the limitation is due to OS.  Closing.

--
Yusuke Endoh <mame@tsg.ne.jp>
----------------------------------------
Bug #7109: File.utime doesn't set nanoseconds
https://bugs.ruby-lang.org/issues/7109#change-32399

Author: bkabrda (Bohuslav Kabrda)
Status: Rejected
Priority: Normal
Assignee:
Category:
Target version:
ruby -v: ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-linux]


Hi,
I'm having a problem with File.utime on RHEL 5/CentOS 5. The File.utime 
method seems not to set nanoseconds properly, see the attached test 
case, that fails (the nanoseconds get rounded to thousand, so in fact I 
get microseconds). The test doesn't seem to fail on newer platforms with 
the same Ruby version, though (RHEL 6/CentOS 6, Fedora 17). Note, that 
when creating/modifying files, the nanoseconds get set and are returned 
properly, so it seems that they are supported by filesystem.

Sample failure:
  1) Failure:
test_utime(TestUtime) 
[/builddir/build/BUILD/rubygem-sprockets-2.4.5/opt/rh/ruby193/root/usr/share/gems/gems/sprockets-2.4.5/file_utime_fail.rb:10]:
Expected: 391199303
  Actual: 391199000

Any idea what might be wrong?
Thanks!