| 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). |
| posixpaths If CIFS Unix extensions are supported, attempt to |
| negotiate posix path name support which allows certain |
| characters forbidden in typical CIFS filenames, without |
| requiring remapping. (default) |
| noposixpaths If CIFS Unix extensions are supported, do not request |
| posix path name support (this may cause servers to |
| reject creatingfile with certain reserved characters). |
| 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) |
| Experimental When set to 1 used to enable certain experimental |
| features (currently enables multipage writes |
| when signing is enabled, the multipage write |
| performance enhancement was disabled when |
| signing turned on in case buffer was modified |
| just before it was sent, also this flag will |
| be used to use the new experimental sessionsetup |
| code). |
| |
| 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). |