The CIFS VFS support for Linux supports many advanced network filesystem 
features such as heirarchical dfs like namespace, hardlinks, locking and more.  
It was designed to comply with the SNIA CIFS Technical Reference (which 
supersedes the 1992 X/Open SMB Standard) as well as to perform best practice 
practical interoperability with Windows 2000, Windows XP, Samba and equivalent 
servers.  

For questions or bug reports please contact:
    sfrench@samba.org (sfrench@us.ibm.com) 

Build instructions:
==================
For Linux 2.4:
1) Get the kernel source (e.g.from http://www.kernel.org)
and download the cifs vfs source (see the project page
at http://us1.samba.org/samba/Linux_CIFS_client.html)
and change directory into the top of the kernel directory
then patch the kernel (e.g. "patch -p1 < cifs_24.patch") 
to add the cifs vfs to your kernel configure options if
it has not already been added (e.g. current SuSE and UL
users do not need to apply the cifs_24.patch since the cifs vfs is
already in the kernel configure menu) and then
mkdir linux/fs/cifs and then copy the current cifs vfs files from
the cifs download to your kernel build directory e.g.

	cp <cifs_download_dir>/fs/cifs/* to <kernel_download_dir>/fs/cifs
	
2) make menuconfig (or make xconfig)
3) select cifs from within the network filesystem choices
4) save and exit
5) make dep
6) make modules (or "make" if CIFS VFS not to be built as a module)

For Linux 2.5:
1) Download the kernel (e.g. from http://www.kernel.org or from bitkeeper
at bk://linux.bkbits.net/linux-2.5) and change directory into the top
of the kernel directory tree (e.g. /usr/src/linux-2.5.73)
2) make menuconfig (or make xconfig)
3) select cifs from within the network filesystem choices
4) save and exit
5) make


Installation instructions:
=========================
If you have built the CIFS vfs as module (successfully) simply
type "make modules_install" (or if you prefer, manually copy the file to
the modules directory e.g. /lib/modules/2.4.10-4GB/kernel/fs/cifs/cifs.o).

If you have built the CIFS vfs into the kernel itself, follow the instructions
for your distribution on how to install a new kernel (usually you
would simply type "make install").

If you do not have the utility mount.cifs (in the Samba 3.0 source tree and on 
the CIFS VFS web site) copy it to the same directory in which mount.smbfs and 
similar files reside (usually /sbin).  Although the helper software is not  
required, mount.cifs is recommended.  Eventually the Samba 3.0 utility program 
"net" may also be helpful since it may someday provide easier mount syntax for
users who are used to Windows e.g.  net use <mount point> <UNC name or cifs URL>  
Note that running the Winbind pam/nss module (logon service) on all of your
Linux clients is useful in mapping Uids and Gids consistently across the
domain to the proper network user.  The mount.cifs mount helper can be
trivially built from Samba 3.0 or later source e.g. by executing:

	gcc samba/source/client/mount.cifs.c -o mount.cifs
	
There is a corresponding manual page for cifs mounting in the Samba 3.0 and
later source tree in docs/manpages/mount.cifs.8 

Samba Considerations 
==================== 
To get the maximum benefit from the CIFS VFS, we recommend using a server that 
supports the SNIA CIFS Unix Extensions standard (e.g.  Samba 2.2.5 or later or 
Samba 3.0) but the CIFS vfs works fine with a wide variety of CIFS servers.  
Note that uid, gid and file permissions will display default values if you do 
not have a server that supports the Unix extensions for CIFS (such as Samba 
2.2.5 or later).  To enable the Unix CIFS Extensions in the Samba server, add 
the line: 

	unix extensions = yes
	
to your smb.conf file on the server.  Note that the following smb.conf settings 
are also useful (on the Samba server) when the majority of clients are Unix or 
Linux: 

	case sensitive = yes
	delete readonly = yes 
 
Some administrators also change the "map archive" and the "create mask" 
parameters from their default values.  Creating special devices (mknod) remotely 
may require specifying a mkdev function to Samba.  For more information on these 
see the manual pages ("man smb.conf") on the Samba server system.  Note that the 
cifs vfs, unlike the smbfs vfs, does not read the smb.conf on the client system 
(the few optional settings are passed in on mount via -o parameters instead).  
Note that Samba 2.2.7 or later includes a fix that allows the CIFS VFS to delete 
open files (required for strict POSIX compliance).  Windows Servers already 
supported this feature.  

Use instructions:
================
Once the CIFS VFS support is built into the kernel or installed as a module 
(cifs.o), you can use mount syntax like the following to access Samba or Windows 
servers: 

  mount -t cifs //9.53.216.11/e$ /mnt -o user=myname,pass=mypassword
  
after -o the following cifs vfs specific options are supported:

  user=<username>
  pass=<password>
  domain=<domain name>
  
Other cifs mount options are described below.  Use of TCP names (in addition to
ip addresses) is available if the mount helper (mount.cifs) is installed. If
you do not trust the server to which are mounted, or if you do not have
cifs signing enabled (and the physical network is insecure), consider use
of the standard mount options "noexec" and "nosuid" to reduce the risk of 
running an altered binary on your local system (downloaded from a hostile server
or altered by a hostile router).

Restrictions
============
Servers must support the NTLM SMB dialect (which is the most recent, supported 
by Samba and Windows NT, 2000 and XP and many other SMB/CIFS servers) and 
servers must support either "pure-TCP" (port 445 TCP/IP CIFS connections) or RFC 
1001/1002 support for "Netbios-Over-TCP/IP." Neither of these is likely to be a 
problem as most servers support this.  IPv6 support is planned for the future.  

CIFS VFS Mount Options
======================
A partial list of the supported mount options follows:
  user		The user name to use when trying to establish
		the CIFS session.
  password	The user password.  If the mount helper is
		installed, the user will be prompted for password
		if it is not supplied.
  ip		The ip address of the target server
  unc		The target server Universal Network Name (export) to 
		mount.	
  domain	Set the SMB/CIFS workgroup name prepended to the
		username during CIFS session establishment
  uid           If CIFS Unix extensions are not supported by the server
                this overrides the default uid for inodes.
  gid		If CIFS Unix extensions are not supported by the server
		this overrides the default gid for inodes.
  file_mode     If CIFS Unix extensions are not supported by the server
		this overrides the default mode for file inodes.
  dir_mode      If CIFS Unix extensions are not supported by the server 
		this overrides the default mode for directory inodes.
  port		attempt to contact the server on this tcp port, before
		trying the usual ports (port 445, then 139).
  iocharset     Codepage used to convert local path names to and from
		Unicode. Unicode is used by default for network path
		names if the server supports it.  If iocharset is
		not specified then the nls_default specified
		during the local client kernel build will be used.
		If server does not support Unicode, this parameter is
		unused.
  rsize		default read size
  wsize		default write size
  rw		mount the network share read-write (note that the
		server may still consider the share read-only)
  ro		mount network share read-only
  version	used to distinguish different versions of the
		mount helper utility (not typically needed)
  sep		if first mount option (after the -o), overrides
		the comma as the separator between the mount
		parms. e.g.
			-o user=myname,password=mypassword,domain=mydom
		could be passed instead with period as the separator by
			-o sep=.user=myname.password=mypassword.domain=mydom
		this might be useful when comma is contained within username
		or password or domain. This option is less important
		when the cifs mount helper cifs.mount (version 1.1 or later)
		is used.

Misc /proc/fs/cifs Flags and Debug Info
=======================================
Informational pseudo-files:
DebugData		Displays information about active CIFS sessions
SimultaneousOps		Counter which holds maximum number of
			simultaneous outstanding SMB/CIFS requests.
Stats			Lists summary resource usage information

Configuration pseudo-files:
MultiuserMount		If set to one, more than one CIFS session to 
			the same server ip address can be established
			if more than one uid accesses the same mount
			point and if the uids user/password mapping
			information is available. (default is 0)
PacketSigningEnabled	If set to one, cifs packet signing is enabled
			and will be used if the server requires 
			it.  If set to two, cifs packet signing is
			required even if the server considers packet
			signing optional. (default 1)
cifsFYI			If set to one, additional debug information is
			logged to the system error log. (default 0)
ExtendedSecurity	If set to one, SPNEGO session establishment
			is allowed which enables more advanced 
			secure CIFS session establishment (default 0)
NTLMV2Enabled		If set to one, more secure password hashes
			are used when the server supports them and
			when kerberos is not negotiated (default 0)
traceSMB		If set to one, debug information is logged to the
			system error log with the start of smb requests
			and responses (default 0)
LookupCacheEnable	If set to one, inode information is kept cached
			for one second improving performance of lookups
			(default 1)
OplockEnabled		If set to one, safe distributed caching enabled.
			(default 1)
LinuxExtensionsEnabled	If set to one then the client will attempt to
			use the CIFS "UNIX" extensions which are optional
			protocol enhancements that allow CIFS servers
			to return accurate UID/GID information as well
			as support symbolic links. If you use servers
			such as Samba that support the CIFS Unix
			extensions but do not want to use symbolic link
			support and want to map the uid and gid fields 
			to values supplied at mount (rather than the 
			actual values, then set this to zero. (default 1)

These experimental features and tracing can be enabled by changing flags in 
/proc/fs/cifs (after the cifs module has been installed or built into the 
kernel, e.g.  insmod cifs).  To enable a feature set it to 1 e.g.  to enable 
tracing to the kernel message log type: 

	echo 1 > /proc/fs/cifs/cifsFYI
	
and for more extensive tracing including the start of smb requests and responses

	echo 1 > /proc/fs/cifs/traceSMB
	
Also note that "cat /proc/fs/cifs/DebugData" will display some information about 
the active sessions and the shares that are mounted.  Note: NTLMv2 enablement 
will not work since they its implementation is not quite complete yet.
Do not alter these configuration values unless you are doing specific testing.  
Enabling extended security works to Windows 2000 Workstations and XP but not to 
Windows 2000 server or Samba since it does not usually send "raw NTLMSSP" 
(instead it sends NTLMSSP encapsulated in SPNEGO/GSSAPI, which support is not 
complete in the CIFS VFS yet).  
