[linux-cifs-client] cifs client caching wrong data

[Bjørn Tore Sund]

We distribute home directories to 600 linux clients using Samba and 
cifs.  Since upgrading from Fedora 10 (mount.cifs from samba 3.2.15, 
cifs kernel module version 1.54 on 2.6.27) to Fedora 12 (mount.cifs from 
Samba 3.4.5, cifs kernel module version 1.60 on 2.6.31) on the clients 
we have issues with updates on the file systems never being noticed on 
the client site.

The quick test we run is to do:

mkdir a b c d e f g h i j k l m n o p q r s t u v w x; ls -a ?

Either that, or an immediately following:

rmdir ?; mkdir a b c d e f g h i j k l m n o p q r s t u v w x; ls -a ?

will trigger the issue.  Normally the first one and always the second 
one will on all or most directories fail to show them containing "." and 
"..".  The issue is wider, we're seeing file corruptions and "ls" 
displaying the content of a different directory than the current working 
directory but these are not predictably reproducable.  The behaviour is 
similar to what we saw before we started mounting with nobrl two or 
three years ago which leads me to suspect that nobrl somehow have 
stopped being taken into account.  Once the client have started showing 
wrong data for a directory no amount of prodding beyond unmounting and 
remounting will make it show correct info again.

Server is the latest on SuSE Enterprise 10 (3.0.32), no changes have 
been made to the configuration here, but we have tried 3.0.33 from RHEL5 
and a self-compiled 3.4.5 on RHEL5 with no difference, nor did a manual 
downgrade of mount.cifs to 3.2.15 on the clients have any effect. 
Relevant parts of smb.conf on the server would be:

         enhanced browsing = yes
         unix extensions = yes
         kernel oplocks = yes
         posix locking = yes
         strict locking = no
         locking = yes
         wide links = yes
         mangled names = no
         delete readonly = No

[homes]
         comment = Home Directories
         valid users = %S
         browseable = No
         read only = No
         inherit acls = Yes

mount.cifs is called with options nobrl and serverino.

It is entirely possible that this is a Fedora issue but I need to start 
somewhere and this would be the place where people know the most about 
the cifs client and might have seen something like this before.

-BT
-- 
Bjørn Tore Sund       Phone: 555-84894   Email:   bjorn.sund at it.uib.no
IT department         VIP:   81724       Support: http://bs.uib.no
Univ. of Bergen

When in fear and when in doubt, run in circles, scream and shout.