Hi Jeff,
I had the same idea.
When mounting the CIFS directory, the problematic installations return 0
links for both dirs and files. On the other hand, the stock CentOS
installation return 1 or more links.
It puzzled me. Two questions:
- anyone know the rationale behind this?
- how it is possible to work-around that with an unpatched kernel?
Thank you and regards.
On 02/11/2014 04:33 PM, Jeff Layton wrote:
On Tue, 11 Feb 2014 10:30:13 +0100
Gionatan Danti <g.danti@xxxxxxxxxx> wrote:
Hi all,
I have a strange problem trying to re-share, via Samba, a CIFS mount.
Let first explain my network topology:
Win2008R2 w/SMB share -> low speed link -> Linux Box -> WIN7 clients
In short, a Win2008 R2 share is being accessed by some W7 clients over a
slow (~8 Mb/s downstream, ~1 Mb/s upstream) ADSL link. To speed up read
operation on the branch office, I thought to use a Linux Box with
cachefilesd and a CONFIG_CIFS_FSCACHE enabled kernel. The Linux box will
mount the Win2008R2 share and, thanks to cachefilesd, it will maintain
an "hot cache" of the read data. This CIFS mount is then shared, via
Samba, to the other client Win7 PCs.
However, the problem is that when re-sharing the CIFS mount, the Win7
clients often see the many directories inside the mount as a regular
files, and not directories! In other words, if I have a directory "test"
inside the mount, the client PC will see a _file_ called "test". When
double-clicking on that "file", the Win7 client even ask to select the
application to open it.
The strange this is that this problem happen with some Linux kernel
version, but not with others. These are my results:
1) Stock CentOS 6.5 x86-64 system (kernel 2.6.32-431.1.2.0.1, cifs-utils
4.8.1-19, samba 3.6.9-167): no problem here, but this kernel does not
have CONFIG_CIFS_FSCACHE, so I can not use it for speeding up read access;
2) CentOS 6.5 x86-64 with ElRepo updates (kernel 3.10.28-1): here
CONFIG_CIFS_FSCACHE is enabled, but I have the problem described above;
3) Debian 7 amd64 with latest updates (kernel 3.2.54-2, cifs-utils
2:5.5-1): CONFIG_CIFS_FSCACHE is enabled, problem happens;
4) Fedora 20 x86-64 (kernel 3.12.8-300, cifs-utils 6.3-1, samba
4.1.3-2): CONFIG_CIFS_FSCACHE is enabled and problem does _not_ happen,
however this is a client distro and I am not so comfortable to put it
into production.
Anyone has any explanation of what is happening here?
Regards.
Most likely, the problem is that the cifs mount is returning an
st_nlink value of 0 for directories, and that confuses samba into
thinking that directories are files (I forget their rationale for this).
More recent kernels have patches that make the client fake up st_nlink
values when the server sends 0 for a NumberOfLinks value.
--
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti@xxxxxxxxxx - info@xxxxxxxxxx
GPG public key ID: FF5F32A8
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