553 lines
28 KiB
Plaintext
553 lines
28 KiB
Plaintext
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 2.6:
|
|
1) Download the kernel (e.g. from http://www.kernel.org)
|
|
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
|
|
|
|
If cifs is built as a module, then the size and number of network buffers
|
|
and maximum number of simultaneous requests to one server can be configured.
|
|
Changing these from their defaults is not recommended. By executing modinfo
|
|
modinfo kernel/fs/cifs/cifs.ko
|
|
on kernel/fs/cifs/cifs.ko the list of configuration changes that can be made
|
|
at module initialization time (by running insmod cifs.ko) can be seen.
|
|
|
|
Allowing User Mounts
|
|
====================
|
|
To permit users to mount and unmount over directories they own is possible
|
|
with the cifs vfs. A way to enable such mounting is to mark the mount.cifs
|
|
utility as suid (e.g. "chmod +s /sbin/mount.cifs). To enable users to
|
|
umount shares they mount requires
|
|
1) mount.cifs version 1.4 or later
|
|
2) an entry for the share in /etc/fstab indicating that a user may
|
|
unmount it e.g.
|
|
//server/usersharename /mnt/username cifs user 0 0
|
|
|
|
Note that when the mount.cifs utility is run suid (allowing user mounts),
|
|
in order to reduce risks, the "nosuid" mount flag is passed in on mount to
|
|
disallow execution of an suid program mounted on the remote target.
|
|
When mount is executed as root, nosuid is not passed in by default,
|
|
and execution of suid programs on the remote target would be enabled
|
|
by default. This can be changed, as with nfs and other filesystems,
|
|
by simply specifying "nosuid" among the mount options. For user mounts
|
|
though to be able to pass the suid flag to mount requires rebuilding
|
|
mount.cifs with the following flag:
|
|
|
|
gcc samba/source/client/mount.cifs.c -DCIFS_ALLOW_USR_SUID -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
|
|
|
|
Allowing User Unmounts
|
|
======================
|
|
To permit users to ummount directories that they have user mounted (see above),
|
|
the utility umount.cifs may be used. It may be invoked directly, or if
|
|
umount.cifs is placed in /sbin, umount can invoke the cifs umount helper
|
|
(at least for most versions of the umount utility) for umount of cifs
|
|
mounts, unless umount is invoked with -i (which will avoid invoking a umount
|
|
helper). As with mount.cifs, to enable user unmounts umount.cifs must be marked
|
|
as suid (e.g. "chmod +s /sbin/umount.cifs") or equivalent (some distributions
|
|
allow adding entries to a file to the /etc/permissions file to achieve the
|
|
equivalent suid effect). For this utility to succeed the target path
|
|
must be a cifs mount, and the uid of the current user must match the uid
|
|
of the user who mounted the resource.
|
|
|
|
Also note that the customary way of allowing user mounts and unmounts is
|
|
(instead of using mount.cifs and unmount.cifs as suid) to add a line
|
|
to the file /etc/fstab for each //server/share you wish to mount, but
|
|
this can become unwieldy when potential mount targets include many
|
|
or unpredictable UNC names.
|
|
|
|
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
|
|
ea support = yes
|
|
|
|
Note that server ea support is required for supporting xattrs from the Linux
|
|
cifs client, and that EA support is present in later versions of Samba (e.g.
|
|
3.0.6 and later (also EA support works in all versions of Windows, at least to
|
|
shares on NTFS filesystems). Extended Attribute (xattr) support is an optional
|
|
feature of most Linux filesystems which may require enabling via
|
|
make menuconfig. Client support for extended attributes (user xattr) can be
|
|
disabled on a per-mount basis by specifying "nouser_xattr" on mount.
|
|
|
|
The CIFS client can get and set POSIX ACLs (getfacl, setfacl) to Samba servers
|
|
version 3.10 and later. Setting POSIX ACLs requires enabling both XATTR and
|
|
then POSIX support in the CIFS configuration options when building the cifs
|
|
module. POSIX ACL support can be disabled on a per mount basic by specifying
|
|
"noacl" on mount.
|
|
|
|
Some administrators may want to change Samba's smb.conf "map archive" and
|
|
"create mask" parameters from the default. Unless the create mask is changed
|
|
newly created files can end up with an unnecessarily restrictive default mode,
|
|
which may not be what you want, although if the CIFS Unix extensions are
|
|
enabled on the server and client, subsequent setattr calls (e.g. chmod) can
|
|
fix the mode. Note that creating special devices (mknod) remotely
|
|
may require specifying a mkdev function to Samba if you are not using
|
|
Samba 3.0.6 or later. 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. Samba server does not allow symlinks that refer to files
|
|
outside of the share, so in Samba versions prior to 3.0.6, most symlinks to
|
|
files with absolute paths (ie beginning with slash) such as:
|
|
ln -s /mnt/foo bar
|
|
would be forbidden. Samba 3.0.6 server or later includes the ability to create
|
|
such symlinks safely by converting unsafe symlinks (ie symlinks to server
|
|
files that are outside of the share) to a samba specific format on the server
|
|
that is ignored by local server applications and non-cifs clients and that will
|
|
not be traversed by the Samba server). This is opaque to the Linux client
|
|
application using the cifs vfs. Absolute symlinks will work to Samba 3.0.5 or
|
|
later, but only for remote clients using the CIFS Unix extensions, and will
|
|
be invisbile to Windows clients and typically will not affect local
|
|
applications running on the same server as Samba.
|
|
|
|
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
|
|
|
|
Before -o the option -v may be specified to make the mount.cifs
|
|
mount helper display the mount steps more verbosely.
|
|
After -o the following commonly used 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).
|
|
|
|
Although mounting using format corresponding to the CIFS URL specification is
|
|
not possible in mount.cifs yet, it is possible to use an alternate format
|
|
for the server and sharename (which is somewhat similar to NFS style mount
|
|
syntax) instead of the more widely used UNC format (i.e. \\server\share):
|
|
mount -t cifs tcp_name_of_server:share_name /mnt -o user=myname,pass=mypasswd
|
|
|
|
When using the mount helper mount.cifs, passwords may be specified via alternate
|
|
mechanisms, instead of specifying it after -o using the normal "pass=" syntax
|
|
on the command line:
|
|
1) By including it in a credential file. Specify credentials=filename as one
|
|
of the mount options. Credential files contain two lines
|
|
username=someuser
|
|
password=your_password
|
|
2) By specifying the password in the PASSWD environment variable (similarly
|
|
the user name can be taken from the USER environment variable).
|
|
3) By specifying the password in a file by name via PASSWD_FILE
|
|
4) By specifying the password in a file by file descriptor via PASSWD_FD
|
|
|
|
If no password is provided, mount.cifs will prompt for password entry
|
|
|
|
Restrictions
|
|
============
|
|
Servers must support the NTLM SMB dialect (which is the most recent, supported
|
|
by Samba and Windows NT version 4, 2000 and XP and many other SMB/CIFS servers)
|
|
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,
|
|
and is almost complete.
|
|
|
|
Valid filenames differ between Windows and Linux. Windows typically restricts
|
|
filenames which contain certain reserved characters (e.g.the character :
|
|
which is used to delimit the beginning of a stream name by Windows), while
|
|
Linux allows a slightly wider set of valid characters in filenames. Windows
|
|
servers can remap such characters when an explicit mapping is specified in
|
|
the Server's registry. Samba starting with version 3.10 will allow such
|
|
filenames (ie those which contain valid Linux characters, which normally
|
|
would be forbidden for Windows/CIFS semantics) as long as the server is
|
|
configured for Unix Extensions (and the client has not disabled
|
|
/proc/fs/cifs/LinuxExtensionsEnabled).
|
|
|
|
|
|
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. For mounts to
|
|
servers which do support the CIFS Unix extensions, such
|
|
as a properly configured Samba server, the server provides
|
|
the uid, gid and mode. For servers which do not support
|
|
the Unix extensions, the default uid (and gid) returned on
|
|
lookup of existing files is the uid (gid) of the person
|
|
who executed the mount (root, except when mount.cifs
|
|
is configured setuid for user mounts) unless the "uid="
|
|
(gid) mount option is specified. For the uid (gid) of newly
|
|
created files and directories, ie files created since
|
|
the last mount of the server share, the expected uid
|
|
(gid) is cached as as long as the inode remains in
|
|
memory on the client. Also note that permission
|
|
checks (authorization checks) on accesses to a file occur
|
|
at the server, but there are cases in which an administrator
|
|
may want to restrict at the client as well. For those
|
|
servers which do not report a uid/gid owner
|
|
(such as Windows), permissions can also be checked at the
|
|
client, and a crude form of client side permission checking
|
|
can be enabled by specifying file_mode and dir_mode on
|
|
the client. Note that the mount.cifs helper must be
|
|
at version 1.10 or higher to support specifying the uid
|
|
(or gid) in non-numberic form.
|
|
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 (usually 16K)
|
|
wsize default write size (usually 16K, 32K is often better over GigE)
|
|
maximum wsize currently allowed by CIFS is 57344 (14 4096 byte
|
|
pages)
|
|
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.
|
|
nosuid Do not allow remote executables with the suid bit
|
|
program to be executed. This is only meaningful for mounts
|
|
to servers such as Samba which support the CIFS Unix Extensions.
|
|
If you do not trust the servers in your network (your mount
|
|
targets) it is recommended that you specify this option for
|
|
greater security.
|
|
exec Permit execution of binaries on the mount.
|
|
noexec Do not permit execution of binaries on the mount.
|
|
dev Recognize block devices on the remote mount.
|
|
nodev Do not recognize devices on the remote mount.
|
|
suid Allow remote files on this mountpoint with suid enabled to
|
|
be executed (default for mounts when executed as root,
|
|
nosuid is default for user mounts).
|
|
credentials Although ignored by the cifs kernel component, it is used by
|
|
the mount helper, mount.cifs. When mount.cifs is installed it
|
|
opens and reads the credential file specified in order
|
|
to obtain the userid and password arguments which are passed to
|
|
the cifs vfs.
|
|
guest Although ignored by the kernel component, the mount.cifs
|
|
mount helper will not prompt the user for a password
|
|
if guest is specified on the mount options. If no
|
|
password is specified a null password will be used.
|
|
perm Client does permission checks (vfs_permission check of uid
|
|
and gid of the file against the mode and desired operation),
|
|
Note that this is in addition to the normal ACL check on the
|
|
target machine done by the server software.
|
|
Client permission checking is enabled by default.
|
|
noperm Client does not do permission checks. This can expose
|
|
files on this mount to access by other users on the local
|
|
client system. It is typically only needed when the server
|
|
supports the CIFS Unix Extensions but the UIDs/GIDs on the
|
|
client and server system do not match closely enough to allow
|
|
access by the user doing the mount, but it may be useful with
|
|
non CIFS Unix Extension mounts for cases in which the default
|
|
mode is specified on the mount but is not to be enforced on the
|
|
client (e.g. perhaps when MultiUserMount is enabled)
|
|
Note that this does not affect the normal ACL check on the
|
|
target machine done by the server software (of the server
|
|
ACL against the user name provided at mount time).
|
|
serverino Use servers inode numbers instead of generating automatically
|
|
incrementing inode numbers on the client. Although this will
|
|
make it easier to spot hardlinked files (as they will have
|
|
the same inode numbers) and inode numbers may be persistent,
|
|
note that the server does not guarantee that the inode numbers
|
|
are unique if multiple server side mounts are exported under a
|
|
single share (since inode numbers on the servers might not
|
|
be unique if multiple filesystems are mounted under the same
|
|
shared higher level directory). Note that this requires that
|
|
the server support the CIFS Unix Extensions as other servers
|
|
do not return a unique IndexNumber on SMB FindFirst (most
|
|
servers return zero as the IndexNumber). Parameter has no
|
|
effect to Windows servers and others which do not support the
|
|
CIFS Unix Extensions.
|
|
noserverino Client generates inode numbers (rather than using the actual one
|
|
from the server) by default.
|
|
setuids If the CIFS Unix extensions are negotiated with the server
|
|
the client will attempt to set the effective uid and gid of
|
|
the local process on newly created files, directories, and
|
|
devices (create, mkdir, mknod). If the CIFS Unix Extensions
|
|
are not negotiated, for newly created files and directories
|
|
instead of using the default uid and gid specified on the
|
|
the mount, cache the new file's uid and gid locally which means
|
|
that the uid for the file can change when the inode is
|
|
reloaded (or the user remounts the share).
|
|
nosetuids The client will not attempt to set the uid and gid on
|
|
on newly created files, directories, and devices (create,
|
|
mkdir, mknod) which will result in the server setting the
|
|
uid and gid to the default (usually the server uid of the
|
|
user who mounted the share). Letting the server (rather than
|
|
the client) set the uid and gid is the default. If the CIFS
|
|
Unix Extensions are not negotiated then the uid and gid for
|
|
new files will appear to be the uid (gid) of the mounter or the
|
|
uid (gid) parameter specified on the mount.
|
|
netbiosname When mounting to servers via port 139, specifies the RFC1001
|
|
source name to use to represent the client netbios machine
|
|
name when doing the RFC1001 netbios session initialize.
|
|
direct Do not do inode data caching on files opened on this mount.
|
|
This precludes mmaping files on this mount. In some cases
|
|
with fast networks and little or no caching benefits on the
|
|
client (e.g. when the application is doing large sequential
|
|
reads bigger than page size without rereading the same data)
|
|
this can provide better performance than the default
|
|
behavior which caches reads (readahead) and writes
|
|
(writebehind) through the local Linux client pagecache
|
|
if oplock (caching token) is granted and held. Note that
|
|
direct allows write operations larger than page size
|
|
to be sent to the server.
|
|
acl Allow setfacl and getfacl to manage posix ACLs if server
|
|
supports them. (default)
|
|
noacl Do not allow setfacl and getfacl calls on this mount
|
|
user_xattr Allow getting and setting user xattrs as OS/2 EAs (extended
|
|
attributes) to the server (default) e.g. via setfattr
|
|
and getfattr utilities.
|
|
nouser_xattr Do not allow getfattr/setfattr to get/set xattrs
|
|
mapchars Translate six of the seven reserved characters (not backslash)
|
|
*?<>|:
|
|
to the remap range (above 0xF000), which also
|
|
allows the CIFS client to recognize files created with
|
|
such characters by Windows's POSIX emulation. This can
|
|
also be useful when mounting to most versions of Samba
|
|
(which also forbids creating and opening files
|
|
whose names contain any of these seven characters).
|
|
This has no effect if the server does not support
|
|
Unicode on the wire.
|
|
nomapchars Do not translate any of these seven characters (default).
|
|
nocase Request case insensitive path name matching (case
|
|
sensitive is the default if the server suports it).
|
|
nobrl Do not send byte range lock requests to the server.
|
|
This is necessary for certain applications that break
|
|
with cifs style mandatory byte range locks (and most
|
|
cifs servers do not yet support requesting advisory
|
|
byte range locks).
|
|
remount remount the share (often used to change from ro to rw mounts
|
|
or vice versa)
|
|
sfu When the CIFS Unix Extensions are not negotiated, attempt to
|
|
create device files and fifos in a format compatible with
|
|
Services for Unix (SFU). In addition retrieve bits 10-12
|
|
of the mode via the SETFILEBITS extended attribute (as
|
|
SFU does). In the future the bottom 9 bits of the mode
|
|
mode also will be emulated using queries of the security
|
|
descriptor (ACL).
|
|
sec Security mode. Allowed values are:
|
|
none attempt to connection as a null user (no name)
|
|
krb5 Use Kerberos version 5 authentication
|
|
krb5i Use Kerberos authentication and packet signing
|
|
ntlm Use NTLM password hashing (default)
|
|
ntlmi Use NTLM password hashing with signing (if
|
|
/proc/fs/cifs/PacketSigningEnabled on or if
|
|
server requires signing also can be the default)
|
|
ntlmv2 Use NTLMv2 password hashing
|
|
ntlmv2i Use NTLMv2 password hashing with packet signing
|
|
|
|
The mount.cifs mount helper also accepts a few mount options before -o
|
|
including:
|
|
|
|
-S take password from stdin (equivalent to setting the environment
|
|
variable "PASSWD_FD=0"
|
|
-V print mount.cifs version
|
|
-? display simple usage information
|
|
|
|
With recent 2.6 kernel versions of modutils, the version of the cifs kernel
|
|
module can be displayed via modinfo.
|
|
|
|
Misc /proc/fs/cifs Flags and Debug Info
|
|
=======================================
|
|
Informational pseudo-files:
|
|
DebugData Displays information about active CIFS sessions
|
|
and shares, as well as the cifs.ko version.
|
|
Stats Lists summary resource usage information as well as per
|
|
share statistics, if CONFIG_CIFS_STATS in enabled
|
|
in the kernel configuration.
|
|
|
|
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 7 > /proc/fs/cifs/cifsFYI
|
|
|
|
cifsFYI functions as a bit mask. Setting it to 1 enables additional kernel
|
|
logging of various informational messages. 2 enables logging of non-zero
|
|
SMB return codes while 4 enables logging of requests that take longer
|
|
than one second to complete (except for byte range lock requests).
|
|
Setting it to 4 requires defining CONFIG_CIFS_STATS2 manually in the
|
|
source code (typically by setting it in the beginning of cifsglob.h),
|
|
and setting it to seven enables all three. Finally, tracing
|
|
the start of smb requests and responses can be enabled via:
|
|
|
|
echo 1 > /proc/fs/cifs/traceSMB
|
|
|
|
Two other experimental features are under development and to test
|
|
require enabling CONFIG_CIFS_EXPERIMENTAL
|
|
|
|
More efficient write operations
|
|
|
|
DNOTIFY fcntl: needed for support of directory change
|
|
notification and perhaps later for file leases)
|
|
|
|
Per share (per client mount) statistics are available in /proc/fs/cifs/Stats
|
|
if the kernel was configured with cifs statistics enabled. The statistics
|
|
represent the number of successful (ie non-zero return code from the server)
|
|
SMB responses to some of the more common commands (open, delete, mkdir etc.).
|
|
Also recorded is the total bytes read and bytes written to the server for
|
|
that share. Note that due to client caching effects this can be less than the
|
|
number of bytes read and written by the application running on the client.
|
|
The statistics for the number of total SMBs and oplock breaks are different in
|
|
that they represent all for that share, not just those for which the server
|
|
returned success.
|
|
|
|
Also note that "cat /proc/fs/cifs/DebugData" will display information about
|
|
the active sessions and the shares that are mounted. Note: NTLMv2 enablement
|
|
will not work since its implementation is not quite complete yet. Do not alter
|
|
the ExtendedSecurity configuration value 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).
|