1 The CIFS VFS support for Linux supports many advanced network filesystem
2 features such as hierarchical dfs like namespace, hardlinks, locking and more.
3 It was designed to comply with the SNIA CIFS Technical Reference (which
4 supersedes the 1992 X/Open SMB Standard) as well as to perform best practice
5 practical interoperability with Windows 2000, Windows XP, Samba and equivalent
8 For questions or bug reports please contact:
9 sfrench@samba.org (sfrench@us.ibm.com)
14 1) Get the kernel source (e.g.from http://www.kernel.org)
15 and download the cifs vfs source (see the project page
16 at http://us1.samba.org/samba/Linux_CIFS_client.html)
17 and change directory into the top of the kernel directory
18 then patch the kernel (e.g. "patch -p1 < cifs_24.patch")
19 to add the cifs vfs to your kernel configure options if
20 it has not already been added (e.g. current SuSE and UL
21 users do not need to apply the cifs_24.patch since the cifs vfs is
22 already in the kernel configure menu) and then
23 mkdir linux/fs/cifs and then copy the current cifs vfs files from
24 the cifs download to your kernel build directory e.g.
26 cp <cifs_download_dir>/fs/cifs/* to <kernel_download_dir>/fs/cifs
28 2) make menuconfig (or make xconfig)
29 3) select cifs from within the network filesystem choices
32 6) make modules (or "make" if CIFS VFS not to be built as a module)
35 1) Download the kernel (e.g. from http://www.kernel.org)
36 and change directory into the top of the kernel directory tree
37 (e.g. /usr/src/linux-2.5.73)
38 2) make menuconfig (or make xconfig)
39 3) select cifs from within the network filesystem choices
44 Installation instructions:
45 =========================
46 If you have built the CIFS vfs as module (successfully) simply
47 type "make modules_install" (or if you prefer, manually copy the file to
48 the modules directory e.g. /lib/modules/2.4.10-4GB/kernel/fs/cifs/cifs.o).
50 If you have built the CIFS vfs into the kernel itself, follow the instructions
51 for your distribution on how to install a new kernel (usually you
52 would simply type "make install").
54 If you do not have the utility mount.cifs (in the Samba 3.0 source tree and on
55 the CIFS VFS web site) copy it to the same directory in which mount.smbfs and
56 similar files reside (usually /sbin). Although the helper software is not
57 required, mount.cifs is recommended. Eventually the Samba 3.0 utility program
58 "net" may also be helpful since it may someday provide easier mount syntax for
59 users who are used to Windows e.g. net use <mount point> <UNC name or cifs URL>
60 Note that running the Winbind pam/nss module (logon service) on all of your
61 Linux clients is useful in mapping Uids and Gids consistently across the
62 domain to the proper network user. The mount.cifs mount helper can be
63 trivially built from Samba 3.0 or later source e.g. by executing:
65 gcc samba/source/client/mount.cifs.c -o mount.cifs
67 If cifs is built as a module, then the size and number of network buffers
68 and maximum number of simultaneous requests to one server can be configured.
69 Changing these from their defaults is not recommended. By executing modinfo
70 modinfo kernel/fs/cifs/cifs.ko
71 on kernel/fs/cifs/cifs.ko the list of configuration changes that can be made
72 at module initialization time (by running insmod cifs.ko) can be seen.
76 To permit users to mount and unmount over directories they own is possible
77 with the cifs vfs. A way to enable such mounting is to mark the mount.cifs
78 utility as suid (e.g. "chmod +s /sbin/mount.cifs). To enable users to
79 umount shares they mount requires
80 1) mount.cifs version 1.4 or later
81 2) an entry for the share in /etc/fstab indicating that a user may
83 //server/usersharename /mnt/username cifs user 0 0
85 Note that when the mount.cifs utility is run suid (allowing user mounts),
86 in order to reduce risks, the "nosuid" mount flag is passed in on mount to
87 disallow execution of an suid program mounted on the remote target.
88 When mount is executed as root, nosuid is not passed in by default,
89 and execution of suid programs on the remote target would be enabled
90 by default. This can be changed, as with nfs and other filesystems,
91 by simply specifying "nosuid" among the mount options. For user mounts
92 though to be able to pass the suid flag to mount requires rebuilding
93 mount.cifs with the following flag:
95 gcc samba/source/client/mount.cifs.c -DCIFS_ALLOW_USR_SUID -o mount.cifs
97 There is a corresponding manual page for cifs mounting in the Samba 3.0 and
98 later source tree in docs/manpages/mount.cifs.8
100 Allowing User Unmounts
101 ======================
102 To permit users to ummount directories that they have user mounted (see above),
103 the utility umount.cifs may be used. It may be invoked directly, or if
104 umount.cifs is placed in /sbin, umount can invoke the cifs umount helper
105 (at least for most versions of the umount utility) for umount of cifs
106 mounts, unless umount is invoked with -i (which will avoid invoking a umount
107 helper). As with mount.cifs, to enable user unmounts umount.cifs must be marked
108 as suid (e.g. "chmod +s /sbin/umount.cifs") or equivalent (some distributions
109 allow adding entries to a file to the /etc/permissions file to achieve the
110 equivalent suid effect). For this utility to succeed the target path
111 must be a cifs mount, and the uid of the current user must match the uid
112 of the user who mounted the resource.
114 Also note that the customary way of allowing user mounts and unmounts is
115 (instead of using mount.cifs and unmount.cifs as suid) to add a line
116 to the file /etc/fstab for each //server/share you wish to mount, but
117 this can become unwieldy when potential mount targets include many
118 or unpredictable UNC names.
122 To get the maximum benefit from the CIFS VFS, we recommend using a server that
123 supports the SNIA CIFS Unix Extensions standard (e.g. Samba 2.2.5 or later or
124 Samba 3.0) but the CIFS vfs works fine with a wide variety of CIFS servers.
125 Note that uid, gid and file permissions will display default values if you do
126 not have a server that supports the Unix extensions for CIFS (such as Samba
127 2.2.5 or later). To enable the Unix CIFS Extensions in the Samba server, add
130 unix extensions = yes
132 to your smb.conf file on the server. Note that the following smb.conf settings
133 are also useful (on the Samba server) when the majority of clients are Unix or
137 delete readonly = yes
140 Note that server ea support is required for supporting xattrs from the Linux
141 cifs client, and that EA support is present in later versions of Samba (e.g.
142 3.0.6 and later (also EA support works in all versions of Windows, at least to
143 shares on NTFS filesystems). Extended Attribute (xattr) support is an optional
144 feature of most Linux filesystems which may require enabling via
145 make menuconfig. Client support for extended attributes (user xattr) can be
146 disabled on a per-mount basis by specifying "nouser_xattr" on mount.
148 The CIFS client can get and set POSIX ACLs (getfacl, setfacl) to Samba servers
149 version 3.10 and later. Setting POSIX ACLs requires enabling both XATTR and
150 then POSIX support in the CIFS configuration options when building the cifs
151 module. POSIX ACL support can be disabled on a per mount basic by specifying
154 Some administrators may want to change Samba's smb.conf "map archive" and
155 "create mask" parameters from the default. Unless the create mask is changed
156 newly created files can end up with an unnecessarily restrictive default mode,
157 which may not be what you want, although if the CIFS Unix extensions are
158 enabled on the server and client, subsequent setattr calls (e.g. chmod) can
159 fix the mode. Note that creating special devices (mknod) remotely
160 may require specifying a mkdev function to Samba if you are not using
161 Samba 3.0.6 or later. For more information on these see the manual pages
162 ("man smb.conf") on the Samba server system. Note that the cifs vfs,
163 unlike the smbfs vfs, does not read the smb.conf on the client system
164 (the few optional settings are passed in on mount via -o parameters instead).
165 Note that Samba 2.2.7 or later includes a fix that allows the CIFS VFS to delete
166 open files (required for strict POSIX compliance). Windows Servers already
167 supported this feature. Samba server does not allow symlinks that refer to files
168 outside of the share, so in Samba versions prior to 3.0.6, most symlinks to
169 files with absolute paths (ie beginning with slash) such as:
171 would be forbidden. Samba 3.0.6 server or later includes the ability to create
172 such symlinks safely by converting unsafe symlinks (ie symlinks to server
173 files that are outside of the share) to a samba specific format on the server
174 that is ignored by local server applications and non-cifs clients and that will
175 not be traversed by the Samba server). This is opaque to the Linux client
176 application using the cifs vfs. Absolute symlinks will work to Samba 3.0.5 or
177 later, but only for remote clients using the CIFS Unix extensions, and will
178 be invisbile to Windows clients and typically will not affect local
179 applications running on the same server as Samba.
183 Once the CIFS VFS support is built into the kernel or installed as a module
184 (cifs.o), you can use mount syntax like the following to access Samba or Windows
187 mount -t cifs //9.53.216.11/e$ /mnt -o user=myname,pass=mypassword
189 Before -o the option -v may be specified to make the mount.cifs
190 mount helper display the mount steps more verbosely.
191 After -o the following commonly used cifs vfs specific options
198 Other cifs mount options are described below. Use of TCP names (in addition to
199 ip addresses) is available if the mount helper (mount.cifs) is installed. If
200 you do not trust the server to which are mounted, or if you do not have
201 cifs signing enabled (and the physical network is insecure), consider use
202 of the standard mount options "noexec" and "nosuid" to reduce the risk of
203 running an altered binary on your local system (downloaded from a hostile server
204 or altered by a hostile router).
206 Although mounting using format corresponding to the CIFS URL specification is
207 not possible in mount.cifs yet, it is possible to use an alternate format
208 for the server and sharename (which is somewhat similar to NFS style mount
209 syntax) instead of the more widely used UNC format (i.e. \\server\share):
210 mount -t cifs tcp_name_of_server:share_name /mnt -o user=myname,pass=mypasswd
212 When using the mount helper mount.cifs, passwords may be specified via alternate
213 mechanisms, instead of specifying it after -o using the normal "pass=" syntax
215 1) By including it in a credential file. Specify credentials=filename as one
216 of the mount options. Credential files contain two lines
218 password=your_password
219 2) By specifying the password in the PASSWD environment variable (similarly
220 the user name can be taken from the USER environment variable).
221 3) By specifying the password in a file by name via PASSWD_FILE
222 4) By specifying the password in a file by file descriptor via PASSWD_FD
224 If no password is provided, mount.cifs will prompt for password entry
228 Servers must support the NTLM SMB dialect (which is the most recent, supported
229 by Samba and Windows NT version 4, 2000 and XP and many other SMB/CIFS servers)
230 Servers must support either "pure-TCP" (port 445 TCP/IP CIFS connections) or RFC
231 1001/1002 support for "Netbios-Over-TCP/IP." Neither of these is likely to be a
232 problem as most servers support this. IPv6 support is planned for the future,
233 and is almost complete.
235 Valid filenames differ between Windows and Linux. Windows typically restricts
236 filenames which contain certain reserved characters (e.g.the character :
237 which is used to delimit the beginning of a stream name by Windows), while
238 Linux allows a slightly wider set of valid characters in filenames. Windows
239 servers can remap such characters when an explicit mapping is specified in
240 the Server's registry. Samba starting with version 3.10 will allow such
241 filenames (ie those which contain valid Linux characters, which normally
242 would be forbidden for Windows/CIFS semantics) as long as the server is
243 configured for Unix Extensions (and the client has not disabled
244 /proc/fs/cifs/LinuxExtensionsEnabled).
247 CIFS VFS Mount Options
248 ======================
249 A partial list of the supported mount options follows:
250 user The user name to use when trying to establish
252 password The user password. If the mount helper is
253 installed, the user will be prompted for password
254 if it is not supplied.
255 ip The ip address of the target server
256 unc The target server Universal Network Name (export) to
258 domain Set the SMB/CIFS workgroup name prepended to the
259 username during CIFS session establishment
260 uid Set the default uid for inodes. For mounts to servers
261 which do support the CIFS Unix extensions, such as a
262 properly configured Samba server, the server provides
263 the uid, gid and mode so this parameter should not be
264 specified unless the server and clients uid and gid
265 numbering differ. If the server and client are in the
266 same domain (e.g. running winbind or nss_ldap) and
267 the server supports the Unix Extensions then the uid
268 and gid can be retrieved from the server (and uid
269 and gid would not have to be specifed on the mount.
270 For servers which do not support the CIFS Unix
271 extensions, the default uid (and gid) returned on lookup
272 of existing files will be the uid (gid) of the person
273 who executed the mount (root, except when mount.cifs
274 is configured setuid for user mounts) unless the "uid="
275 (gid) mount option is specified. For the uid (gid) of newly
276 created files and directories, ie files created since
277 the last mount of the server share, the expected uid
278 (gid) is cached as long as the inode remains in
279 memory on the client. Also note that permission
280 checks (authorization checks) on accesses to a file occur
281 at the server, but there are cases in which an administrator
282 may want to restrict at the client as well. For those
283 servers which do not report a uid/gid owner
284 (such as Windows), permissions can also be checked at the
285 client, and a crude form of client side permission checking
286 can be enabled by specifying file_mode and dir_mode on
287 the client. Note that the mount.cifs helper must be
288 at version 1.10 or higher to support specifying the uid
289 (or gid) in non-numberic form.
290 gid Set the default gid for inodes (similar to above).
291 file_mode If CIFS Unix extensions are not supported by the server
292 this overrides the default mode for file inodes.
293 dir_mode If CIFS Unix extensions are not supported by the server
294 this overrides the default mode for directory inodes.
295 port attempt to contact the server on this tcp port, before
296 trying the usual ports (port 445, then 139).
297 iocharset Codepage used to convert local path names to and from
298 Unicode. Unicode is used by default for network path
299 names if the server supports it. If iocharset is
300 not specified then the nls_default specified
301 during the local client kernel build will be used.
302 If server does not support Unicode, this parameter is
304 rsize default read size (usually 16K)
305 wsize default write size (usually 16K, 32K is often better over GigE)
306 maximum wsize currently allowed by CIFS is 57344 (14 4096 byte
308 rw mount the network share read-write (note that the
309 server may still consider the share read-only)
310 ro mount network share read-only
311 version used to distinguish different versions of the
312 mount helper utility (not typically needed)
313 sep if first mount option (after the -o), overrides
314 the comma as the separator between the mount
316 -o user=myname,password=mypassword,domain=mydom
317 could be passed instead with period as the separator by
318 -o sep=.user=myname.password=mypassword.domain=mydom
319 this might be useful when comma is contained within username
320 or password or domain. This option is less important
321 when the cifs mount helper cifs.mount (version 1.1 or later)
323 nosuid Do not allow remote executables with the suid bit
324 program to be executed. This is only meaningful for mounts
325 to servers such as Samba which support the CIFS Unix Extensions.
326 If you do not trust the servers in your network (your mount
327 targets) it is recommended that you specify this option for
329 exec Permit execution of binaries on the mount.
330 noexec Do not permit execution of binaries on the mount.
331 dev Recognize block devices on the remote mount.
332 nodev Do not recognize devices on the remote mount.
333 suid Allow remote files on this mountpoint with suid enabled to
334 be executed (default for mounts when executed as root,
335 nosuid is default for user mounts).
336 credentials Although ignored by the cifs kernel component, it is used by
337 the mount helper, mount.cifs. When mount.cifs is installed it
338 opens and reads the credential file specified in order
339 to obtain the userid and password arguments which are passed to
341 guest Although ignored by the kernel component, the mount.cifs
342 mount helper will not prompt the user for a password
343 if guest is specified on the mount options. If no
344 password is specified a null password will be used.
345 perm Client does permission checks (vfs_permission check of uid
346 and gid of the file against the mode and desired operation),
347 Note that this is in addition to the normal ACL check on the
348 target machine done by the server software.
349 Client permission checking is enabled by default.
350 noperm Client does not do permission checks. This can expose
351 files on this mount to access by other users on the local
352 client system. It is typically only needed when the server
353 supports the CIFS Unix Extensions but the UIDs/GIDs on the
354 client and server system do not match closely enough to allow
355 access by the user doing the mount, but it may be useful with
356 non CIFS Unix Extension mounts for cases in which the default
357 mode is specified on the mount but is not to be enforced on the
358 client (e.g. perhaps when MultiUserMount is enabled)
359 Note that this does not affect the normal ACL check on the
360 target machine done by the server software (of the server
361 ACL against the user name provided at mount time).
362 serverino Use servers inode numbers instead of generating automatically
363 incrementing inode numbers on the client. Although this will
364 make it easier to spot hardlinked files (as they will have
365 the same inode numbers) and inode numbers may be persistent,
366 note that the server does not guarantee that the inode numbers
367 are unique if multiple server side mounts are exported under a
368 single share (since inode numbers on the servers might not
369 be unique if multiple filesystems are mounted under the same
370 shared higher level directory). Note that this requires that
371 the server support the CIFS Unix Extensions as other servers
372 do not return a unique IndexNumber on SMB FindFirst (most
373 servers return zero as the IndexNumber). Parameter has no
374 effect to Windows servers and others which do not support the
375 CIFS Unix Extensions.
376 noserverino Client generates inode numbers (rather than using the actual one
377 from the server) by default.
378 setuids If the CIFS Unix extensions are negotiated with the server
379 the client will attempt to set the effective uid and gid of
380 the local process on newly created files, directories, and
381 devices (create, mkdir, mknod). If the CIFS Unix Extensions
382 are not negotiated, for newly created files and directories
383 instead of using the default uid and gid specified on
384 the mount, cache the new file's uid and gid locally which means
385 that the uid for the file can change when the inode is
386 reloaded (or the user remounts the share).
387 nosetuids The client will not attempt to set the uid and gid on
388 on newly created files, directories, and devices (create,
389 mkdir, mknod) which will result in the server setting the
390 uid and gid to the default (usually the server uid of the
391 user who mounted the share). Letting the server (rather than
392 the client) set the uid and gid is the default. If the CIFS
393 Unix Extensions are not negotiated then the uid and gid for
394 new files will appear to be the uid (gid) of the mounter or the
395 uid (gid) parameter specified on the mount.
396 netbiosname When mounting to servers via port 139, specifies the RFC1001
397 source name to use to represent the client netbios machine
398 name when doing the RFC1001 netbios session initialize.
399 direct Do not do inode data caching on files opened on this mount.
400 This precludes mmaping files on this mount. In some cases
401 with fast networks and little or no caching benefits on the
402 client (e.g. when the application is doing large sequential
403 reads bigger than page size without rereading the same data)
404 this can provide better performance than the default
405 behavior which caches reads (readahead) and writes
406 (writebehind) through the local Linux client pagecache
407 if oplock (caching token) is granted and held. Note that
408 direct allows write operations larger than page size
409 to be sent to the server.
410 acl Allow setfacl and getfacl to manage posix ACLs if server
411 supports them. (default)
412 noacl Do not allow setfacl and getfacl calls on this mount
413 user_xattr Allow getting and setting user xattrs as OS/2 EAs (extended
414 attributes) to the server (default) e.g. via setfattr
415 and getfattr utilities.
416 nouser_xattr Do not allow getfattr/setfattr to get/set/list xattrs
417 mapchars Translate six of the seven reserved characters (not backslash)
419 to the remap range (above 0xF000), which also
420 allows the CIFS client to recognize files created with
421 such characters by Windows's POSIX emulation. This can
422 also be useful when mounting to most versions of Samba
423 (which also forbids creating and opening files
424 whose names contain any of these seven characters).
425 This has no effect if the server does not support
427 nomapchars Do not translate any of these seven characters (default).
428 nocase Request case insensitive path name matching (case
429 sensitive is the default if the server suports it).
430 posixpaths If CIFS Unix extensions are supported, attempt to
431 negotiate posix path name support which allows certain
432 characters forbidden in typical CIFS filenames, without
433 requiring remapping. (default)
434 noposixpaths If CIFS Unix extensions are supported, do not request
435 posix path name support (this may cause servers to
436 reject creatingfile with certain reserved characters).
437 nobrl Do not send byte range lock requests to the server.
438 This is necessary for certain applications that break
439 with cifs style mandatory byte range locks (and most
440 cifs servers do not yet support requesting advisory
442 remount remount the share (often used to change from ro to rw mounts
444 sfu When the CIFS Unix Extensions are not negotiated, attempt to
445 create device files and fifos in a format compatible with
446 Services for Unix (SFU). In addition retrieve bits 10-12
447 of the mode via the SETFILEBITS extended attribute (as
448 SFU does). In the future the bottom 9 bits of the
449 mode also will be emulated using queries of the security
451 sign Must use packet signing (helps avoid unwanted data modification
452 by intermediate systems in the route). Note that signing
453 does not work with lanman or plaintext authentication.
454 sec Security mode. Allowed values are:
455 none attempt to connection as a null user (no name)
456 krb5 Use Kerberos version 5 authentication
457 krb5i Use Kerberos authentication and packet signing
458 ntlm Use NTLM password hashing (default)
459 ntlmi Use NTLM password hashing with signing (if
460 /proc/fs/cifs/PacketSigningEnabled on or if
461 server requires signing also can be the default)
462 ntlmv2 Use NTLMv2 password hashing
463 ntlmv2i Use NTLMv2 password hashing with packet signing
464 lanman (if configured in kernel config) use older
467 The mount.cifs mount helper also accepts a few mount options before -o
470 -S take password from stdin (equivalent to setting the environment
471 variable "PASSWD_FD=0"
472 -V print mount.cifs version
473 -? display simple usage information
475 With most 2.6 kernel versions of modutils, the version of the cifs kernel
476 module can be displayed via modinfo.
478 Misc /proc/fs/cifs Flags and Debug Info
479 =======================================
480 Informational pseudo-files:
481 DebugData Displays information about active CIFS sessions
482 and shares, as well as the cifs.ko version.
483 Stats Lists summary resource usage information as well as per
484 share statistics, if CONFIG_CIFS_STATS in enabled
485 in the kernel configuration.
487 Configuration pseudo-files:
488 MultiuserMount If set to one, more than one CIFS session to
489 the same server ip address can be established
490 if more than one uid accesses the same mount
491 point and if the uids user/password mapping
492 information is available. (default is 0)
493 PacketSigningEnabled If set to one, cifs packet signing is enabled
494 and will be used if the server requires
495 it. If set to two, cifs packet signing is
496 required even if the server considers packet
497 signing optional. (default 1)
498 SecurityFlags Flags which control security negotiation and
499 also packet signing. Authentication (may/must)
500 flags (e.g. for NTLM and/or NTLMv2) may be combined with
501 the signing flags. Specifying two different password
502 hashing mechanisms (as "must use") on the other hand
503 does not make much sense. Default flags are
505 (NTLM, NTLMv2 and packet signing allowed). Maximum
506 allowable flags if you want to allow mounts to servers
507 using weaker password hashes is 0x37037 (lanman,
508 plaintext, ntlm, ntlmv2, signing allowed):
510 may use packet signing 0x00001
511 must use packet signing 0x01001
512 may use NTLM (most common password hash) 0x00002
513 must use NTLM 0x02002
514 may use NTLMv2 0x00004
515 must use NTLMv2 0x04004
516 may use Kerberos security (not implemented yet) 0x00008
517 must use Kerberos (not implemented yet) 0x08008
518 may use lanman (weak) password hash 0x00010
519 must use lanman password hash 0x10010
520 may use plaintext passwords 0x00020
521 must use plaintext passwords 0x20020
522 (reserved for future packet encryption) 0x00040
524 cifsFYI If set to non-zero value, additional debug information
525 will be logged to the system error log. This field
526 contains three flags controlling different classes of
527 debugging entries. The maximum value it can be set
528 to is 7 which enables all debugging points (default 0).
529 Some debugging statements are not compiled into the
530 cifs kernel unless CONFIG_CIFS_DEBUG2 is enabled in the
531 kernel configuration. cifsFYI may be set to one or
532 nore of the following flags (7 sets them all):
534 log cifs informational messages 0x01
535 log return codes from cifs entry points 0x02
536 log slow responses (ie which take longer than 1 second)
537 CONFIG_CIFS_STATS2 must be enabled in .config 0x04
540 traceSMB If set to one, debug information is logged to the
541 system error log with the start of smb requests
542 and responses (default 0)
543 LookupCacheEnable If set to one, inode information is kept cached
544 for one second improving performance of lookups
546 OplockEnabled If set to one, safe distributed caching enabled.
548 LinuxExtensionsEnabled If set to one then the client will attempt to
549 use the CIFS "UNIX" extensions which are optional
550 protocol enhancements that allow CIFS servers
551 to return accurate UID/GID information as well
552 as support symbolic links. If you use servers
553 such as Samba that support the CIFS Unix
554 extensions but do not want to use symbolic link
555 support and want to map the uid and gid fields
556 to values supplied at mount (rather than the
557 actual values, then set this to zero. (default 1)
558 Experimental When set to 1 used to enable certain experimental
559 features (currently enables multipage writes
560 when signing is enabled, the multipage write
561 performance enhancement was disabled when
562 signing turned on in case buffer was modified
563 just before it was sent, also this flag will
564 be used to use the new experimental sessionsetup
567 These experimental features and tracing can be enabled by changing flags in
568 /proc/fs/cifs (after the cifs module has been installed or built into the
569 kernel, e.g. insmod cifs). To enable a feature set it to 1 e.g. to enable
570 tracing to the kernel message log type:
572 echo 7 > /proc/fs/cifs/cifsFYI
574 cifsFYI functions as a bit mask. Setting it to 1 enables additional kernel
575 logging of various informational messages. 2 enables logging of non-zero
576 SMB return codes while 4 enables logging of requests that take longer
577 than one second to complete (except for byte range lock requests).
578 Setting it to 4 requires defining CONFIG_CIFS_STATS2 manually in the
579 source code (typically by setting it in the beginning of cifsglob.h),
580 and setting it to seven enables all three. Finally, tracing
581 the start of smb requests and responses can be enabled via:
583 echo 1 > /proc/fs/cifs/traceSMB
585 Two other experimental features are under development and to test
586 require enabling CONFIG_CIFS_EXPERIMENTAL
588 More efficient write operations
590 DNOTIFY fcntl: needed for support of directory change
591 notification and perhaps later for file leases)
593 Per share (per client mount) statistics are available in /proc/fs/cifs/Stats
594 if the kernel was configured with cifs statistics enabled. The statistics
595 represent the number of successful (ie non-zero return code from the server)
596 SMB responses to some of the more common commands (open, delete, mkdir etc.).
597 Also recorded is the total bytes read and bytes written to the server for
598 that share. Note that due to client caching effects this can be less than the
599 number of bytes read and written by the application running on the client.
600 The statistics for the number of total SMBs and oplock breaks are different in
601 that they represent all for that share, not just those for which the server
604 Also note that "cat /proc/fs/cifs/DebugData" will display information about
605 the active sessions and the shares that are mounted. Note: NTLMv2 enablement
606 will not work since its implementation is not quite complete yet. Do not alter
607 the ExtendedSecurity configuration value unless you are doing specific testing.
608 Enabling extended security works to Windows 2000 Workstations and XP but not to
609 Windows 2000 server or Samba since it does not usually send "raw NTLMSSP"
610 (instead it sends NTLMSSP encapsulated in SPNEGO/GSSAPI, which support is not
611 complete in the CIFS VFS yet).
projects / linux-2.6 / blob