bug#31184: tail -f on Network FS not refreshing as soon as the file is changed.

[Jewsco Pius Jacquez]

Padraig, thanks a lot for your help on this.

We found a workaround combined with cache=none mount option and it works for 
our customer. You can close this case.

tail --follow=name --max-unchanged-stats=1 --sleep-interval=.01 <filename>

thanks,
jewsco

-----Original Message-----
From: Pádraig Brady [mailto:address@hidden 
Sent: Wednesday, May 23, 2018 12:10 AM
To: Jewsco Pius Jacquez <address@hidden>; address@hidden
Subject: Re: bug#31184: tail -f on Network FS not refreshing as soon as the 
file is changed.

On 22/05/18 14:23, Jewsco Pius Jacquez wrote:
> Any more ideas?
> 
> Thanks,
> Jewsco
> 
> -----Original Message-----
> From: Jewsco Pius Jacquez
> Sent: Tuesday, May 8, 2018 8:56 AM
> To: 'Pádraig Brady' <address@hidden>; address@hidden
> Subject: RE: bug#31184: tail -f on Network FS not refreshing as soon as the 
> file is changed.
> 
> Thanks
> 
> Still the same, the -f doesn't refresh. it applies to CIFS and NFS 
> filesystem. Is it something related on how the network filesystem was 
> designed?
> 
> Thanks,
> Jewsco
> 
> -----Original Message-----
> From: Pádraig Brady [mailto:address@hidden
> Sent: Saturday, May 5, 2018 5:52 PM
> To: Jewsco Pius Jacquez <address@hidden>; 
> address@hidden
> Subject: Re: bug#31184: tail -f on Network FS not refreshing as soon as the 
> file is changed.
> 
> On 04/05/18 08:12, Jewsco Pius Jacquez wrote:
>> Thanks, did I missed anything?
>>
>> address@hidden ~]$ wget --quiet 
>> https://ftpmirror.gnu.org/coreutils/coreutils-8.29.tar.xz
>> address@hidden ~]$ cksum coreutils-8.29.tar.xz
>> 926393761 5286588 coreutils-8.29.tar.xz
>> address@hidden ~]$ tar -xf coreutils-8.29.tar.xz
>> address@hidden ~]$ cd coreutils-8.29/
>> address@hidden coreutils-8.29]$ wget --quiet 
>> 'https://github.com/coreutils/coreutils/commit/7fc7206.patch' -O- | 
>> patch -R -p1 && make patching file NEWS Unreversed patch detected!
>> Ignore -R? [n] Apply anyway? [n] Skipping patch.
>> 1 out of 1 hunk ignored -- saving rejects to file NEWS.rej patching 
>> file src/tail.c Hunk #1 FAILED at 1220.
>> 1 out of 1 hunk FAILED -- saving rejects to file src/tail.c.rej
>> address@hidden coreutils-8.29]$
>>
>>
>>
>> Thanks,
>> Jewsco
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: Pádraig Brady [mailto:address@hidden
>> Sent: Thursday, May 3, 2018 8:47 PM
>> To: Jewsco Pius Jacquez <address@hidden>; 
>> address@hidden
>> Subject: Re: bug#31184: tail -f on Network FS not refreshing as soon as the 
>> file is changed.
>>
>> On 02/05/18 06:39, Jewsco Pius Jacquez wrote:
>>> I tried and the --follow=name doesn't refresh either. The stat output is 
>>> changing.
>>>
>>> address@hidden ~]$ tail --follow=name /media/samba/test.file 
>>> append Wed May  2 08:35:54 CDT 2018 append Wed May  2 08:35:54 CDT
>>> 2018 append Wed May  2 08:35:54 CDT 2018 append Wed May  2 08:35:54 
>>> CDT 2018 append Wed May  2 08:35:54 CDT 2018 append Wed May  2
>>> 08:35:54 CDT 2018 append Wed May  2 08:35:54 CDT 2018 append Wed May
>>> 2 08:35:54 CDT 2018 append Wed May  2 08:35:54 CDT 2018 append Wed 
>>> May
>>> 2 08:35:55 CDT 2018 ^C
>>> address@hidden ~]$ tail --follow=name /media/samba/test.file 
>>> append Wed May  2 08:36:01 CDT 2018 append Wed May  2 08:36:01 CDT
>>> 2018 append Wed May  2 08:36:01 CDT 2018 append Wed May  2 08:36:02 
>>> CDT 2018 append Wed May  2 08:36:02 CDT 2018 append Wed May  2
>>> 08:36:02 CDT 2018 append Wed May  2 08:36:02 CDT 2018 append Wed May
>>> 2 08:36:02 CDT 2018 append Wed May  2 08:36:02 CDT 2018 append Wed 
>>> May
>>> 2 08:36:02 CDT 2018 ^C
>>> address@hidden ~]$ while :; do stat -c '%s' 
>>> /media/samba/test.file; sleep 1; done
>>> 1649717
>>> 1650077
>>> 1650401
>>> 1650761
>>> 1651121
>>> 1651445
>>> 1651769
>>> 1652093
>>> 1652417
>>>
>>>
>>> About the reverting the patch, so I need to download the source and patch 
>>> it?
>>>
>>>   cd coreutils-8.29 &&
>>>   wget 'https://github.com/coreutils/coreutils/commit/7fc7206.patch' -O- |
>>>   patch -R -p1 &&
>>>   make
>>
>> You'd done that previously, for for completeness yes you need to download 
>> the source first like:
>>
>>   wget https://ftpmirror.gnu.org/coreutils/coreutils-8.29.tar.xz
>>   tar -xf coreutils-8.29.tar.xz
> 
> Drats sorry. There were conflicting patches in the meantime.
> You can tweak it like:
> 
>  cd coreutils-8.29 &&
>  wget 'https://github.com/coreutils/coreutils/commit/7fc7206.patch' 
> -O- |  sed 's/name,/false, name,/' |  patch -p1 -R -t &&  make
> 
> cheers,
> Pádraig
> This message and the information contained herein is proprietary and 
> confidential and subject to the Amdocs policy statement,

Well I can't repro with 8.29 on nfs here.
Perhaps the read() is blocking or something.
It would be useful to get the output of:

  strace -o tail.strace tail -f /media/samba/test.file

Also for completeness, it would be good to give the command used to write to 
the file on the remote end.

thanks,
Pádraig

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