[linux-cifs-client] Re: cfs client

[Steven French]

Robert,
If you are not using the mount helper (mount.cifs), the mount syntax for 
2.4 requires a parameter after the -o (unc=//ip_address/share) that is not 
required for 2.6.   That is an obvious possible reason for differences 
between 2.4 and 2.6 mount behavior.   Turning on informational logging 
("echo 1 > /proc/fs/cifs/cifsFYI") will allow more detailed information to 
be returned about mount failures to the kernel message log (dmesg). 

No good solution for returning more granular mount errors on 2.4 has been 
proposed.  Since 2.4 kernel itself (unlike 2.6 which fixed this) does not 
allow return codes to be passed back from the key kernel vfs mount routine 
(get superblock), the sys_mount API uses a generic error when mount of 
network filesystems fail (unless the mount code is put in userspace, 
outside the kernel, as smbfs does, in which case this problem is avoided 
but it createst others).   The most recent mount helper source 
(mount.cifs.c) in Samba CVS is much improved but does not have a solution 
for this 2.4 kernel specific problem with better return codes on mount.

There are some not so elegant solutions for returning better errors on 
mount in 2.4 - e.g. stuffing the return code in /proc/fs/cifs/error.  The 
obvious solutions such as putting the errors in errno or environment 
variables or overwriting the mount parms with the error on return don't 
seem feasible.   Alternative solutions would be welcome since this is a 
usability problem with 2.4 


Steve French
Senior Software Engineer
Linux Technology Center - IBM Austin
phone: 512-838-2294
email: sfrench at-sign us dot ibm dot com




"Robert Rothberg" <rrothbe at emory.edu>
01/06/2004 04:39 PM
 
        To:     Steven French/Austin/IBM at IBMUS
        cc:     <client at lists.samba.org>
        Subject:        Re: cfs client


I built a Red Hat box with 2.6 SE Linux and 2.4.20 Linux. I implemented 
CIFS in the 2.6 version with few problems. I saved my mount command in a 
little script to save typing. After I patched and built my 2.4 kernel with 
the CIFS built-in, I boot up into this kernel version and try to run this 
same script and it always fails. 
 
mount: wrong fs type, bad option, bad superblock on .....
 
I have tried rebuilding the kernel with exactly the same parameters as my 
working 2.6. I would like to be able to patch any production machine 
quickly and easily and mount a cifs share.
 
My second question is this. Can I mount the other way, I mean from a 
Windows box to the Unix machine with the CIFS running?
 
Thanks for your help.
 
----- Original Message ----- 
From: Steven French 
To: Robert Rothberg 
Sent: Monday, December 22, 2003 4:18 PM
Subject: Re: cfs client

Take a look at the file fs/cifs/README and the project page (
http://us1.samba.org/samba/Linux_CIFS_client.html) and then send 
subsequent questions to linux-cifs-client at lists.samba.org


Steve French
Senior Software Engineer
Linux Technology Center - IBM Austin
phone: 512-838-2294
email: sfrench at-sign us dot ibm dot com
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