Again and again there are posts to many mailing lists,
that cifs vfs is handling timestamps improperly.
Regarding legacy servers, special copy operations just fail.
(the todays smbfs vs. cifs legacy problem)

Test environment:
 - latest git cifs vfs is mounted against
    - winNT
    - WinXP
    - OS/2
    - Win98SE

Unfortunately, this one cannot be simply explained in 3 words ...
----------------------------

To make it as clear as possible - the mount commands:
*****************************************************
WinNT server:
=============
mount -t cifs //wrkgk/test /mnt/winnt -o cred=/root/sec/sec_gk,dir_mode=0775,file_mode=0764,uid=gk,gid=users

WinXP server:
=============
mount -t cifs //cboyer/gk /mnt/winxp -o cred=/root/sec/sec_gk,dir_mode=0775,file_mode=0764,uid=gk,gid=users

OS/2 server:
============
mount -t cifs //server01/CIFS /mnt/server -o cred=/root/sec/sec_gk,sec=lanman,servern=SERVER01,port=139,dir_mode=0775,file_mode=0764,uid=gk,gid=users

Win98SE:
========
mount -t cifs //win98/CIFS /mnt/win9x -o cred=/root/sec/sec_gk,servern=WIN98,dir_mode=0775,file_mode=0764,uid=gk,gid=users

------------------------------------------------------

The results of "cp -p local_file /mnt/some_server":
***************************************************
NOTE:
   cp -p src dst 
the '-p' option should preserve time stamps - at least the
last modification time!

WinNT:
======
gk@linux700:~/cifstest> stat dummy.tst && cp -p dummy.tst /mnt/winnt/ && sleep 1 && stat /mnt/winnt/dummy.tst
  File: `dummy.tst'
  Size: 51078           Blocks: 104        IO Block: 4096   regular file
Device: 306h/774d       Inode: 1054939     Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/      gk)   Gid: (  100/   users)
Access: 2008-07-09 04:32:26.000000000 +0200
Modify: 2007-05-07 21:52:40.000000000 +0200
Change: 2008-07-09 04:32:24.000000000 +0200
  File: `/mnt/winnt/dummy.tst'
  Size: 51078           Blocks: 104        IO Block: 16384  regular file
Device: 10h/16d Inode: 11749       Links: 1
Access: (0764/-rwxrw-r--)  Uid: ( 1000/      gk)   Gid: (  100/   users)
Access: 2008-07-09 04:35:06.854217400 +0200   !!!!!!!!!!!!!!!!!!!!!
Modify: 2008-07-09 04:35:06.794122600 +0200   !!!!!!!!!!!!!!!!!!!!!
Change: 2008-07-09 04:35:06.794122600 +0200   !!!!!!!!!!!!!!!!!!!!!

WinXP:
======
gk@linux700:~/cifstest> stat dummy.tst && cp -p dummy.tst /mnt/winxp/ && sleep 1 && stat /mnt/winxp/dummy.tst
  File: `dummy.tst'
  Size: 51078           Blocks: 104        IO Block: 4096   regular file
Device: 306h/774d       Inode: 1054939     Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/      gk)   Gid: (  100/   users)
Access: 2008-07-09 04:32:24.000000000 +0200  !!!!!!!!!!!!!!!!!!!!!!!!
Modify: 2007-05-07 21:52:40.000000000 +0200  !!!!!!!!!!!!!!!!!!!!!!!!
Change: 2008-07-09 04:32:24.000000000 +0200  !!!!!!!!!!!!!!!!!!!!!!!!
  File: `/mnt/winxp/dummy.tst'
  Size: 51078           Blocks: 104        IO Block: 16384  regular file
Device: 11h/17d Inode: 11484       Links: 1
Access: (0764/-rwxrw-r--)  Uid: ( 1000/      gk)   Gid: (  100/   users)
Access: 2008-07-09 04:31:31.012852800 +0200
Modify: 2008-07-09 04:31:31.012852800 +0200
Change: 2008-07-09 04:31:31.012852800 +0200

OS/2:
=====
gk@linux700:~/cifstest> stat dummy.tst && cp -p dummy.tst /mnt/server/ && sleep 1 && stat /mnt/server/dummy.tst
  File: `dummy.tst'
  Size: 51078           Blocks: 104        IO Block: 4096   regular file
Device: 306h/774d       Inode: 1054939     Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/      gk)   Gid: (  100/   users)
Access: 2008-07-09 04:46:16.000000000 +0200
Modify: 2007-05-07 21:52:40.000000000 +0200
Change: 2008-07-09 04:32:24.000000000 +0200
cp: preserving times for `/mnt/server/dummy.tst': Invalid argument

Win98SE:
========
gk@linux700:~/cifstest> stat dummy.tst && cp -p dummy.tst /mnt/win9x/ && sleep 1 && stat /mnt/win9x/dummy.tst
  File: `dummy.tst'
  Size: 51078           Blocks: 104        IO Block: 4096   regular file
Device: 306h/774d       Inode: 1054939     Links: 1
Access: (0644/-rw-r--r--)  Uid: ( 1000/      gk)   Gid: (  100/   users)
Access: 2008-07-09 04:36:04.000000000 +0200
Modify: 2007-05-07 21:52:40.000000000 +0200
Change: 2008-07-09 04:32:24.000000000 +0200
cp: preserving times for `/mnt/win9x/dummy.tst': Invalid argument
-----------------------------------------------------------------

Conclusion:
===========
WinNT and WinXP just _silently_ FAIL!
OS/2 and Win98SE just fail with an error msg!

All this is "a known cifs failure" for weeks now - Jeff Layton
has prepared a (large) patch to "cleanup the cifs_setattr()"
stuff - and I'm waiting to post more legacy functionality.

... but nothing happens ...

A really sad situation, when realizing that even the samba
smbfs helpers smbmount, smbmnt and smbumount have now been
removed in 3.2.x.

Cheers, Günter