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 either "pure-TCP" (port 445 TCP/IP CIFS connections) or RFC
229 1001/1002 support for "Netbios-Over-TCP/IP." This is not likely to be a
230 problem as most servers support this.
232 Valid filenames differ between Windows and Linux. Windows typically restricts
233 filenames which contain certain reserved characters (e.g.the character :
234 which is used to delimit the beginning of a stream name by Windows), while
235 Linux allows a slightly wider set of valid characters in filenames. Windows
236 servers can remap such characters when an explicit mapping is specified in
237 the Server's registry. Samba starting with version 3.10 will allow such
238 filenames (ie those which contain valid Linux characters, which normally
239 would be forbidden for Windows/CIFS semantics) as long as the server is
240 configured for Unix Extensions (and the client has not disabled
241 /proc/fs/cifs/LinuxExtensionsEnabled).
244 CIFS VFS Mount Options
245 ======================
246 A partial list of the supported mount options follows:
247 user The user name to use when trying to establish
249 password The user password. If the mount helper is
250 installed, the user will be prompted for password
251 if it is not supplied.
252 ip The ip address of the target server
253 unc The target server Universal Network Name (export) to
255 domain Set the SMB/CIFS workgroup name prepended to the
256 username during CIFS session establishment
257 uid Set the default uid for inodes. For mounts to servers
258 which do support the CIFS Unix extensions, such as a
259 properly configured Samba server, the server provides
260 the uid, gid and mode so this parameter should not be
261 specified unless the server and clients uid and gid
262 numbering differ. If the server and client are in the
263 same domain (e.g. running winbind or nss_ldap) and
264 the server supports the Unix Extensions then the uid
265 and gid can be retrieved from the server (and uid
266 and gid would not have to be specifed on the mount.
267 For servers which do not support the CIFS Unix
268 extensions, the default uid (and gid) returned on lookup
269 of existing files will be the uid (gid) of the person
270 who executed the mount (root, except when mount.cifs
271 is configured setuid for user mounts) unless the "uid="
272 (gid) mount option is specified. For the uid (gid) of newly
273 created files and directories, ie files created since
274 the last mount of the server share, the expected uid
275 (gid) is cached as long as the inode remains in
276 memory on the client. Also note that permission
277 checks (authorization checks) on accesses to a file occur
278 at the server, but there are cases in which an administrator
279 may want to restrict at the client as well. For those
280 servers which do not report a uid/gid owner
281 (such as Windows), permissions can also be checked at the
282 client, and a crude form of client side permission checking
283 can be enabled by specifying file_mode and dir_mode on
284 the client. Note that the mount.cifs helper must be
285 at version 1.10 or higher to support specifying the uid
286 (or gid) in non-numberic form.
287 gid Set the default gid for inodes (similar to above).
288 file_mode If CIFS Unix extensions are not supported by the server
289 this overrides the default mode for file inodes.
290 dir_mode If CIFS Unix extensions are not supported by the server
291 this overrides the default mode for directory inodes.
292 port attempt to contact the server on this tcp port, before
293 trying the usual ports (port 445, then 139).
294 iocharset Codepage used to convert local path names to and from
295 Unicode. Unicode is used by default for network path
296 names if the server supports it. If iocharset is
297 not specified then the nls_default specified
298 during the local client kernel build will be used.
299 If server does not support Unicode, this parameter is
301 rsize default read size (usually 16K). The client currently
302 can not use rsize larger than CIFSMaxBufSize. CIFSMaxBufSize
303 defaults to 16K and may be changed (from 8K to the maximum
304 kmalloc size allowed by your kernel) at module install time
305 for cifs.ko. Setting CIFSMaxBufSize to a very large value
306 will cause cifs to use more memory and may reduce performance
307 in some cases. To use rsize greater than 127K (the original
308 cifs protocol maximum) also requires that the server support
309 a new Unix Capability flag (for very large read) which some
310 newer servers (e.g. Samba 3.0.26 or later) do. rsize can be
311 set from a minimum of 2048 to a maximum of 130048 (127K or
312 CIFSMaxBufSize, whichever is smaller)
313 wsize default write size (default 57344)
314 maximum wsize currently allowed by CIFS is 57344 (fourteen
316 rw mount the network share read-write (note that the
317 server may still consider the share read-only)
318 ro mount network share read-only
319 version used to distinguish different versions of the
320 mount helper utility (not typically needed)
321 sep if first mount option (after the -o), overrides
322 the comma as the separator between the mount
324 -o user=myname,password=mypassword,domain=mydom
325 could be passed instead with period as the separator by
326 -o sep=.user=myname.password=mypassword.domain=mydom
327 this might be useful when comma is contained within username
328 or password or domain. This option is less important
329 when the cifs mount helper cifs.mount (version 1.1 or later)
331 nosuid Do not allow remote executables with the suid bit
332 program to be executed. This is only meaningful for mounts
333 to servers such as Samba which support the CIFS Unix Extensions.
334 If you do not trust the servers in your network (your mount
335 targets) it is recommended that you specify this option for
337 exec Permit execution of binaries on the mount.
338 noexec Do not permit execution of binaries on the mount.
339 dev Recognize block devices on the remote mount.
340 nodev Do not recognize devices on the remote mount.
341 suid Allow remote files on this mountpoint with suid enabled to
342 be executed (default for mounts when executed as root,
343 nosuid is default for user mounts).
344 credentials Although ignored by the cifs kernel component, it is used by
345 the mount helper, mount.cifs. When mount.cifs is installed it
346 opens and reads the credential file specified in order
347 to obtain the userid and password arguments which are passed to
349 guest Although ignored by the kernel component, the mount.cifs
350 mount helper will not prompt the user for a password
351 if guest is specified on the mount options. If no
352 password is specified a null password will be used.
353 perm Client does permission checks (vfs_permission check of uid
354 and gid of the file against the mode and desired operation),
355 Note that this is in addition to the normal ACL check on the
356 target machine done by the server software.
357 Client permission checking is enabled by default.
358 noperm Client does not do permission checks. This can expose
359 files on this mount to access by other users on the local
360 client system. It is typically only needed when the server
361 supports the CIFS Unix Extensions but the UIDs/GIDs on the
362 client and server system do not match closely enough to allow
363 access by the user doing the mount, but it may be useful with
364 non CIFS Unix Extension mounts for cases in which the default
365 mode is specified on the mount but is not to be enforced on the
366 client (e.g. perhaps when MultiUserMount is enabled)
367 Note that this does not affect the normal ACL check on the
368 target machine done by the server software (of the server
369 ACL against the user name provided at mount time).
370 serverino Use server's inode numbers instead of generating automatically
371 incrementing inode numbers on the client. Although this will
372 make it easier to spot hardlinked files (as they will have
373 the same inode numbers) and inode numbers may be persistent,
374 note that the server does not guarantee that the inode numbers
375 are unique if multiple server side mounts are exported under a
376 single share (since inode numbers on the servers might not
377 be unique if multiple filesystems are mounted under the same
378 shared higher level directory). Note that some older
379 (e.g. pre-Windows 2000) do not support returning UniqueIDs
380 or the CIFS Unix Extensions equivalent and for those
381 this mount option will have no effect. Exporting cifs mounts
382 under nfsd requires this mount option on the cifs mount.
383 noserverino Client generates inode numbers (rather than using the actual one
384 from the server) by default.
385 setuids If the CIFS Unix extensions are negotiated with the server
386 the client will attempt to set the effective uid and gid of
387 the local process on newly created files, directories, and
388 devices (create, mkdir, mknod). If the CIFS Unix Extensions
389 are not negotiated, for newly created files and directories
390 instead of using the default uid and gid specified on
391 the mount, cache the new file's uid and gid locally which means
392 that the uid for the file can change when the inode is
393 reloaded (or the user remounts the share).
394 nosetuids The client will not attempt to set the uid and gid on
395 on newly created files, directories, and devices (create,
396 mkdir, mknod) which will result in the server setting the
397 uid and gid to the default (usually the server uid of the
398 user who mounted the share). Letting the server (rather than
399 the client) set the uid and gid is the default. If the CIFS
400 Unix Extensions are not negotiated then the uid and gid for
401 new files will appear to be the uid (gid) of the mounter or the
402 uid (gid) parameter specified on the mount.
403 netbiosname When mounting to servers via port 139, specifies the RFC1001
404 source name to use to represent the client netbios machine
405 name when doing the RFC1001 netbios session initialize.
406 direct Do not do inode data caching on files opened on this mount.
407 This precludes mmaping files on this mount. In some cases
408 with fast networks and little or no caching benefits on the
409 client (e.g. when the application is doing large sequential
410 reads bigger than page size without rereading the same data)
411 this can provide better performance than the default
412 behavior which caches reads (readahead) and writes
413 (writebehind) through the local Linux client pagecache
414 if oplock (caching token) is granted and held. Note that
415 direct allows write operations larger than page size
416 to be sent to the server.
417 acl Allow setfacl and getfacl to manage posix ACLs if server
418 supports them. (default)
419 noacl Do not allow setfacl and getfacl calls on this mount
420 user_xattr Allow getting and setting user xattrs as OS/2 EAs (extended
421 attributes) to the server (default) e.g. via setfattr
422 and getfattr utilities.
423 nouser_xattr Do not allow getfattr/setfattr to get/set/list xattrs
424 mapchars Translate six of the seven reserved characters (not backslash)
426 to the remap range (above 0xF000), which also
427 allows the CIFS client to recognize files created with
428 such characters by Windows's POSIX emulation. This can
429 also be useful when mounting to most versions of Samba
430 (which also forbids creating and opening files
431 whose names contain any of these seven characters).
432 This has no effect if the server does not support
434 nomapchars Do not translate any of these seven characters (default).
435 nocase Request case insensitive path name matching (case
436 sensitive is the default if the server suports it).
437 posixpaths If CIFS Unix extensions are supported, attempt to
438 negotiate posix path name support which allows certain
439 characters forbidden in typical CIFS filenames, without
440 requiring remapping. (default)
441 noposixpaths If CIFS Unix extensions are supported, do not request
442 posix path name support (this may cause servers to
443 reject creatingfile with certain reserved characters).
444 nounix Disable the CIFS Unix Extensions for this mount (tree
445 connection). This is rarely needed, but it may be useful
446 in order to turn off multiple settings all at once (ie
447 posix acls, posix locks, posix paths, symlink support
448 and retrieving uids/gids/mode from the server) or to
449 work around a bug in server which implement the Unix
451 nobrl Do not send byte range lock requests to the server.
452 This is necessary for certain applications that break
453 with cifs style mandatory byte range locks (and most
454 cifs servers do not yet support requesting advisory
456 remount remount the share (often used to change from ro to rw mounts
458 cifsacl Report mode bits (e.g. on stat) based on the Windows ACL for
459 the file. (EXPERIMENTAL)
460 servern Specify the server 's netbios name (RFC1001 name) to use
461 when attempting to setup a session to the server. This is
462 This is needed for mounting to some older servers (such
463 as OS/2 or Windows 98 and Windows ME) since they do not
464 support a default server name. A server name can be up
465 to 15 characters long and is usually uppercased.
466 sfu When the CIFS Unix Extensions are not negotiated, attempt to
467 create device files and fifos in a format compatible with
468 Services for Unix (SFU). In addition retrieve bits 10-12
469 of the mode via the SETFILEBITS extended attribute (as
470 SFU does). In the future the bottom 9 bits of the
471 mode also will be emulated using queries of the security
473 sign Must use packet signing (helps avoid unwanted data modification
474 by intermediate systems in the route). Note that signing
475 does not work with lanman or plaintext authentication.
476 sec Security mode. Allowed values are:
477 none attempt to connection as a null user (no name)
478 krb5 Use Kerberos version 5 authentication
479 krb5i Use Kerberos authentication and packet signing
480 ntlm Use NTLM password hashing (default)
481 ntlmi Use NTLM password hashing with signing (if
482 /proc/fs/cifs/PacketSigningEnabled on or if
483 server requires signing also can be the default)
484 ntlmv2 Use NTLMv2 password hashing
485 ntlmv2i Use NTLMv2 password hashing with packet signing
486 lanman (if configured in kernel config) use older
489 The mount.cifs mount helper also accepts a few mount options before -o
492 -S take password from stdin (equivalent to setting the environment
493 variable "PASSWD_FD=0"
494 -V print mount.cifs version
495 -? display simple usage information
497 With most 2.6 kernel versions of modutils, the version of the cifs kernel
498 module can be displayed via modinfo.
500 Misc /proc/fs/cifs Flags and Debug Info
501 =======================================
502 Informational pseudo-files:
503 DebugData Displays information about active CIFS sessions
504 and shares, as well as the cifs.ko version.
505 Stats Lists summary resource usage information as well as per
506 share statistics, if CONFIG_CIFS_STATS in enabled
507 in the kernel configuration.
509 Configuration pseudo-files:
510 MultiuserMount If set to one, more than one CIFS session to
511 the same server ip address can be established
512 if more than one uid accesses the same mount
513 point and if the uids user/password mapping
514 information is available. (default is 0)
515 PacketSigningEnabled If set to one, cifs packet signing is enabled
516 and will be used if the server requires
517 it. If set to two, cifs packet signing is
518 required even if the server considers packet
519 signing optional. (default 1)
520 SecurityFlags Flags which control security negotiation and
521 also packet signing. Authentication (may/must)
522 flags (e.g. for NTLM and/or NTLMv2) may be combined with
523 the signing flags. Specifying two different password
524 hashing mechanisms (as "must use") on the other hand
525 does not make much sense. Default flags are
527 (NTLM, NTLMv2 and packet signing allowed). Maximum
528 allowable flags if you want to allow mounts to servers
529 using weaker password hashes is 0x37037 (lanman,
530 plaintext, ntlm, ntlmv2, signing allowed):
532 may use packet signing 0x00001
533 must use packet signing 0x01001
534 may use NTLM (most common password hash) 0x00002
535 must use NTLM 0x02002
536 may use NTLMv2 0x00004
537 must use NTLMv2 0x04004
538 may use Kerberos security (not implemented yet) 0x00008
539 must use Kerberos (not implemented yet) 0x08008
540 may use lanman (weak) password hash 0x00010
541 must use lanman password hash 0x10010
542 may use plaintext passwords 0x00020
543 must use plaintext passwords 0x20020
544 (reserved for future packet encryption) 0x00040
546 cifsFYI If set to non-zero value, additional debug information
547 will be logged to the system error log. This field
548 contains three flags controlling different classes of
549 debugging entries. The maximum value it can be set
550 to is 7 which enables all debugging points (default 0).
551 Some debugging statements are not compiled into the
552 cifs kernel unless CONFIG_CIFS_DEBUG2 is enabled in the
553 kernel configuration. cifsFYI may be set to one or
554 nore of the following flags (7 sets them all):
556 log cifs informational messages 0x01
557 log return codes from cifs entry points 0x02
558 log slow responses (ie which take longer than 1 second)
559 CONFIG_CIFS_STATS2 must be enabled in .config 0x04
562 traceSMB If set to one, debug information is logged to the
563 system error log with the start of smb requests
564 and responses (default 0)
565 LookupCacheEnable If set to one, inode information is kept cached
566 for one second improving performance of lookups
568 OplockEnabled If set to one, safe distributed caching enabled.
570 LinuxExtensionsEnabled If set to one then the client will attempt to
571 use the CIFS "UNIX" extensions which are optional
572 protocol enhancements that allow CIFS servers
573 to return accurate UID/GID information as well
574 as support symbolic links. If you use servers
575 such as Samba that support the CIFS Unix
576 extensions but do not want to use symbolic link
577 support and want to map the uid and gid fields
578 to values supplied at mount (rather than the
579 actual values, then set this to zero. (default 1)
580 Experimental When set to 1 used to enable certain experimental
581 features (currently enables multipage writes
582 when signing is enabled, the multipage write
583 performance enhancement was disabled when
584 signing turned on in case buffer was modified
585 just before it was sent, also this flag will
586 be used to use the new experimental directory change
589 These experimental features and tracing can be enabled by changing flags in
590 /proc/fs/cifs (after the cifs module has been installed or built into the
591 kernel, e.g. insmod cifs). To enable a feature set it to 1 e.g. to enable
592 tracing to the kernel message log type:
594 echo 7 > /proc/fs/cifs/cifsFYI
596 cifsFYI functions as a bit mask. Setting it to 1 enables additional kernel
597 logging of various informational messages. 2 enables logging of non-zero
598 SMB return codes while 4 enables logging of requests that take longer
599 than one second to complete (except for byte range lock requests).
600 Setting it to 4 requires defining CONFIG_CIFS_STATS2 manually in the
601 source code (typically by setting it in the beginning of cifsglob.h),
602 and setting it to seven enables all three. Finally, tracing
603 the start of smb requests and responses can be enabled via:
605 echo 1 > /proc/fs/cifs/traceSMB
607 Two other experimental features are under development. To test these
608 requires enabling CONFIG_CIFS_EXPERIMENTAL
610 cifsacl support needed to retrieve approximated mode bits based on
611 the contents on the CIFS ACL.
613 DNOTIFY fcntl: needed for support of directory change
614 notification and perhaps later for file leases)
616 Per share (per client mount) statistics are available in /proc/fs/cifs/Stats
617 if the kernel was configured with cifs statistics enabled. The statistics
618 represent the number of successful (ie non-zero return code from the server)
619 SMB responses to some of the more common commands (open, delete, mkdir etc.).
620 Also recorded is the total bytes read and bytes written to the server for
621 that share. Note that due to client caching effects this can be less than the
622 number of bytes read and written by the application running on the client.
623 The statistics for the number of total SMBs and oplock breaks are different in
624 that they represent all for that share, not just those for which the server
627 Also note that "cat /proc/fs/cifs/DebugData" will display information about
628 the active sessions and the shares that are mounted.
629 Enabling Kerberos (extended security) works when CONFIG_CIFS_EXPERIMENTAL is enabled
630 but requires a user space helper (from the Samba project). NTLM and NTLMv2 and
631 LANMAN support do not require this helpr.
projects / linux-2.6 / blob