Re: Inode link count on mounted Win98 shares

[Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Wed, 21 Mar 2012 12:18:17 +0100
Federico Sauter <fsauter-LVkJPw3T+odGBRGhe+f61g@public.gmane.org> wrote:

> Greetings,
> 
> I want to make some CIFS shared drives accesible through a firewall. For 
> that sake, I have a CIFS shared drive on a Linux box (box0, kernel 
> 2.6.27.57) which is accesible from outside the firewall. On the share on 
> that box I mount all the shared drives from within the firewall so that 
> they can be accessed from client-external.
> 
>    client-external
>      172.16.1.2
>           |
>           |
>      172.16.1.1/24
>     box0 (router, firewall)
>      192.168.1.1/24
>           |
>    +------+-------+
>    |              |
>   win98          winxp
> 192.168.1.2   192.168.1.3
> 
> box0 exports a CIFS shared drive, say \\172.16.1.1\testshare, which 
> refers to local directory, /mnt/share. On /mnt/share I mount two further 
> shared drives, say win98 and winxp. Thus, the contents from win98 and 
> winxp become indirectly visible to the external network 
> (client-external) via 172.16.1.1.
> 
> This works well if I mount \\172.16.1.1\testshare using a Linux-based 
> client-external. Everything works as expected and I can browse the 
> contents of both, winxp and win98. However, when I mount 
> \\172.16.1.1\testshare on a Windows machine, I am unable to browse the 
> contents of the win98 directory. While the winxp directory appears 
> correctly as a folder in the Windows Explorer, the win98 directory 
> appears as a zero byte file (even though it is mounted correctly on box0.)
> 
> I tested the same setup using my local workstation (with Debian squeeze, 
> kernel 2.6.32-5) and came to the same observations. The only difference 
> I could find between the mounted winxp share and the win98 share on box0 
> is that the winxp mount point exhibits an inode link count of 1 after 
> being mounted while the win98 mount point has an inode link count of 0:
> 
> root:/mnt/share# ls -l
> total 8
> (...)
> drwxr-xr-x 0 root root    0 Feb 23 01:39 win98
> drwxr-xr-x 1 root root    0 Mar 13 13:32 winxp
> 
> I have tried pretty much every mount option and the behavior is always 
> the same.
> 
> My questions are:
> 1. Why do Windows 98 mounted shares show this behavior?
> 2. Is there any way to correct this so as to be able to browse these 
> shares indirectly (as described) from a Windows PC?
> 
> Any information would be highly appreciated!
> 
> Kind regards,
> 

That sounds like whatever tool you are using to "browse" is broken.
Just because the link count is 0 doesn't mean that it's a plain file.

The inode link count is provided by the server via the NumberOfLinks
field in the QueryPathInfo response. What you are seeing here is just an
implementation difference between Linux and Windows. Linux usually has
a non-zero inode link count on directories, but at least some versions
of windows will report a link count of 0 for a directory.

As best I can tell -- neither one is more correct than the other.
They're just differences in how this is implemented.

Most likely, this will change in very recent kernels with Pavel's fix
to have the client fake up i_nlink values for directories, once Steve
gets around to merging it.

-- 
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>