Re: CentOS cifs client sees Windows 2012 deduplicated files as symlinks

[Niels Basjes <Niels-WkKhAqUkEt5mR6Xm/wNWPw@public.gmane.org>]

I tried adding the option 'vers=2.1' to the mount but that gave an error:
     mount error(38): Function not implemented

I do not understand why I saw the files as 'chinese letters' before.
After my tests and experiments I have been unable to see them this
way.
Right now I always see them as a symlink to an empty directory (as you
indicated).

A few days ago someone posted on serverfault that in fact this is a
known bug that has been fixed (in kernel 3.13), yet the CentOS 7
distribution has not yet picked up on this problem because it is
running kernel 3.10.

See:
https://bugs.centos.org/view.php?id=7897
http://serverfault.com/questions/697393/centos-cifs-client-sees-windows-2012-deduplicated-files-as-symlinks

Right now I'm considering to install something like this
http://elrepo.org/tiki/kernel-ml and run on Linux Kernel 4.x which
should no longer have this problem.

Niels Basjes


On Thu, Jun 11, 2015 at 6:17 PM, Steve French <smfrench-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Out of curiosity what happens when you mount with smb2 or later (e.g.
> vers=2.1 on mount) - I expect that they will be recognized
> differently.
>
> Copy on write symlinks are reparse points but I would expect them to
> look like empty directories.
>
> On Thu, Jun 11, 2015 at 6:53 AM, Niels Basjes <Niels-WkKhAqUkEt5mR6Xm/wNWPw@public.gmane.org> wrote:
>> Hi,
>>
>> Last week I ran into a serious problem from my CentOS 7 system using
>> the cifs client to mount a volume on a Windows 2012-R2 server.
>> I posted this a problem on ServerFault (
>> http://serverfault.com/q/697393 ) a few days ago but I thought that it
>> is usefull to ask here too.
>> I included some screenshots in the serverfault page so that may be
>> useful to have a look at.
>>
>> The essence of my problem is that the local Windows sysadmin turned on
>> a feature to deduplicate files on an existing Windows server volume.
>> After that my Linux system started seeing all the files that were
>> deduplicated as symlinks to what I can only describe as 'chinese
>> letters'.
>> Under Windows 7 everything works fine.
>>
>> The way I currently look at this is that what is apparently some kind
>> of 'copy-on-write hardlink' on the Windows server is interpreted as a
>> softlink by the cifs client in my CentOS system.
>>
>> I have been experimenting with some mount settings but I have been
>> unable to fix this problem (other than turning off the deduplication).
>>
>> My current (Client) setup:
>> - CentOS 7.0
>> - samba-client-4.1.1-38.el7_0.x86_64
>> - samba-common-4.1.1-38.el7_0.x86_64
>> - samba-libs-4.1.1-38.el7_0.x86_64
>> - cifs-utils-6.2-7.el7.x86_64
>>
>> The command in my /etc/fstab
>>
>> \\xxxxxxxx\file\video /var/www/html/wp-content/uploads cifs
>> nouser_xattr,nounix,iocharset=utf8,credentials=/etc/fstab.cifs.sa_video.credentials,_netdev,uid=apache,gid=apache,rw,auto
>> 0 0
>>
>> How do I get the Linux to see these files as files again?
>>
>>
>> --
>> Best regards / Met vriendelijke groeten,
>>
>> Niels Basjes
>> --
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>
>
>
> --
> Thanks,
>
> Steve



-- 
Best regards / Met vriendelijke groeten,

Niels Basjes