1 ===== 1 =====
2 Usage 2 Usage
3 ===== 3 =====
4 4
5 This module supports the SMB3 family of advanc 5 This module supports the SMB3 family of advanced network protocols (as well
6 as older dialects, originally called "CIFS" or 6 as older dialects, originally called "CIFS" or SMB1).
7 7
8 The CIFS VFS module for Linux supports many ad 8 The CIFS VFS module for Linux supports many advanced network filesystem
9 features such as hierarchical DFS like namespa 9 features such as hierarchical DFS like namespace, hardlinks, locking and more.
10 It was designed to comply with the SNIA CIFS T 10 It was designed to comply with the SNIA CIFS Technical Reference (which
11 supersedes the 1992 X/Open SMB Standard) as we 11 supersedes the 1992 X/Open SMB Standard) as well as to perform best practice
12 practical interoperability with Windows 2000, 12 practical interoperability with Windows 2000, Windows XP, Samba and equivalent
13 servers. This code was developed in participa 13 servers. This code was developed in participation with the Protocol Freedom
14 Information Foundation. CIFS and now SMB3 has 14 Information Foundation. CIFS and now SMB3 has now become a defacto
15 standard for interoperating between Macs and W 15 standard for interoperating between Macs and Windows and major NAS appliances.
16 16
17 Please see 17 Please see
18 MS-SMB2 (for detailed SMB2/SMB3/SMB3.1.1 proto 18 MS-SMB2 (for detailed SMB2/SMB3/SMB3.1.1 protocol specification)
19 or https://samba.org/samba/PFIF/ 19 or https://samba.org/samba/PFIF/
20 for more details. 20 for more details.
21 21
22 22
23 For questions or bug reports please contact: 23 For questions or bug reports please contact:
24 24
25 smfrench@gmail.com 25 smfrench@gmail.com
26 26
27 See the project page at: https://wiki.samba.or 27 See the project page at: https://wiki.samba.org/index.php/LinuxCIFS_utils
28 28
29 Build instructions 29 Build instructions
30 ================== 30 ==================
31 31
32 For Linux: 32 For Linux:
33 33
34 1) Download the kernel (e.g. from https://www. 34 1) Download the kernel (e.g. from https://www.kernel.org)
35 and change directory into the top of the ke 35 and change directory into the top of the kernel directory tree
36 (e.g. /usr/src/linux-2.5.73) 36 (e.g. /usr/src/linux-2.5.73)
37 2) make menuconfig (or make xconfig) 37 2) make menuconfig (or make xconfig)
38 3) select cifs from within the network filesys 38 3) select cifs from within the network filesystem choices
39 4) save and exit 39 4) save and exit
40 5) make 40 5) make
41 41
42 42
43 Installation instructions 43 Installation instructions
44 ========================= 44 =========================
45 45
46 If you have built the CIFS vfs as module (succ 46 If you have built the CIFS vfs as module (successfully) simply
47 type ``make modules_install`` (or if you prefe 47 type ``make modules_install`` (or if you prefer, manually copy the file to
48 the modules directory e.g. /lib/modules/6.3.0- 48 the modules directory e.g. /lib/modules/6.3.0-060300-generic/kernel/fs/smb/client/cifs.ko).
49 49
50 If you have built the CIFS vfs into the kernel 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 51 for your distribution on how to install a new kernel (usually you
52 would simply type ``make install``). 52 would simply type ``make install``).
53 53
54 If you do not have the utility mount.cifs (in 54 If you do not have the utility mount.cifs (in the Samba 4.x source tree and on
55 the CIFS VFS web site) copy it to the same dir 55 the CIFS VFS web site) copy it to the same directory in which mount helpers
56 reside (usually /sbin). Although the helper s 56 reside (usually /sbin). Although the helper software is not
57 required, mount.cifs is recommended. Most dis 57 required, mount.cifs is recommended. Most distros include a ``cifs-utils``
58 package that includes this utility so it is re 58 package that includes this utility so it is recommended to install this.
59 59
60 Note that running the Winbind pam/nss module ( 60 Note that running the Winbind pam/nss module (logon service) on all of your
61 Linux clients is useful in mapping Uids and Gi 61 Linux clients is useful in mapping Uids and Gids consistently across the
62 domain to the proper network user. The mount. 62 domain to the proper network user. The mount.cifs mount helper can be
63 found at cifs-utils.git on git.samba.org 63 found at cifs-utils.git on git.samba.org
64 64
65 If cifs is built as a module, then the size an 65 If cifs is built as a module, then the size and number of network buffers
66 and maximum number of simultaneous requests to 66 and maximum number of simultaneous requests to one server can be configured.
67 Changing these from their defaults is not reco 67 Changing these from their defaults is not recommended. By executing modinfo::
68 68
69 modinfo <path to cifs.ko> 69 modinfo <path to cifs.ko>
70 70
71 on kernel/fs/smb/client/cifs.ko the list of co 71 on kernel/fs/smb/client/cifs.ko the list of configuration changes that can be made
72 at module initialization time (by running insm 72 at module initialization time (by running insmod cifs.ko) can be seen.
73 73
74 Recommendations 74 Recommendations
75 =============== 75 ===============
76 76
77 To improve security the SMB2.1 dialect or late 77 To improve security the SMB2.1 dialect or later (usually will get SMB3.1.1) is now
78 the new default. To use old dialects (e.g. to 78 the new default. To use old dialects (e.g. to mount Windows XP) use "vers=1.0"
79 on mount (or vers=2.0 for Windows Vista). Not 79 on mount (or vers=2.0 for Windows Vista). Note that the CIFS (vers=1.0) is
80 much older and less secure than the default di 80 much older and less secure than the default dialect SMB3 which includes
81 many advanced security features such as downgr 81 many advanced security features such as downgrade attack detection
82 and encrypted shares and stronger signing and 82 and encrypted shares and stronger signing and authentication algorithms.
83 There are additional mount options that may be 83 There are additional mount options that may be helpful for SMB3 to get
84 improved POSIX behavior (NB: can use vers=3 to 84 improved POSIX behavior (NB: can use vers=3 to force SMB3 or later, never 2.1):
85 85
86 ``mfsymlinks`` and either ``cifsacl`` or `` 86 ``mfsymlinks`` and either ``cifsacl`` or ``modefromsid`` (usually with ``idsfromsid``)
87 87
88 Allowing User Mounts 88 Allowing User Mounts
89 ==================== 89 ====================
90 90
91 To permit users to mount and unmount over dire 91 To permit users to mount and unmount over directories they own is possible
92 with the cifs vfs. A way to enable such mount 92 with the cifs vfs. A way to enable such mounting is to mark the mount.cifs
93 utility as suid (e.g. ``chmod +s /sbin/mount.c 93 utility as suid (e.g. ``chmod +s /sbin/mount.cifs``). To enable users to
94 umount shares they mount requires 94 umount shares they mount requires
95 95
96 1) mount.cifs version 1.4 or later 96 1) mount.cifs version 1.4 or later
97 2) an entry for the share in /etc/fstab indica 97 2) an entry for the share in /etc/fstab indicating that a user may
98 unmount it e.g.:: 98 unmount it e.g.::
99 99
100 //server/usersharename /mnt/username cif 100 //server/usersharename /mnt/username cifs user 0 0
101 101
102 Note that when the mount.cifs utility is run s 102 Note that when the mount.cifs utility is run suid (allowing user mounts),
103 in order to reduce risks, the ``nosuid`` mount 103 in order to reduce risks, the ``nosuid`` mount flag is passed in on mount to
104 disallow execution of an suid program mounted 104 disallow execution of an suid program mounted on the remote target.
105 When mount is executed as root, nosuid is not 105 When mount is executed as root, nosuid is not passed in by default,
106 and execution of suid programs on the remote t 106 and execution of suid programs on the remote target would be enabled
107 by default. This can be changed, as with nfs a 107 by default. This can be changed, as with nfs and other filesystems,
108 by simply specifying ``nosuid`` among the moun 108 by simply specifying ``nosuid`` among the mount options. For user mounts
109 though to be able to pass the suid flag to mou 109 though to be able to pass the suid flag to mount requires rebuilding
110 mount.cifs with the following flag: CIFS_ALLOW 110 mount.cifs with the following flag: CIFS_ALLOW_USR_SUID
111 111
112 There is a corresponding manual page for cifs 112 There is a corresponding manual page for cifs mounting in the Samba 3.0 and
113 later source tree in docs/manpages/mount.cifs. 113 later source tree in docs/manpages/mount.cifs.8
114 114
115 Allowing User Unmounts 115 Allowing User Unmounts
116 ====================== 116 ======================
117 117
118 To permit users to unmount directories that th 118 To permit users to unmount directories that they have user mounted (see above),
119 the utility umount.cifs may be used. It may b 119 the utility umount.cifs may be used. It may be invoked directly, or if
120 umount.cifs is placed in /sbin, umount can inv 120 umount.cifs is placed in /sbin, umount can invoke the cifs umount helper
121 (at least for most versions of the umount util 121 (at least for most versions of the umount utility) for umount of cifs
122 mounts, unless umount is invoked with -i (whic 122 mounts, unless umount is invoked with -i (which will avoid invoking a umount
123 helper). As with mount.cifs, to enable user un 123 helper). As with mount.cifs, to enable user unmounts umount.cifs must be marked
124 as suid (e.g. ``chmod +s /sbin/umount.cifs``) 124 as suid (e.g. ``chmod +s /sbin/umount.cifs``) or equivalent (some distributions
125 allow adding entries to a file to the /etc/per 125 allow adding entries to a file to the /etc/permissions file to achieve the
126 equivalent suid effect). For this utility to 126 equivalent suid effect). For this utility to succeed the target path
127 must be a cifs mount, and the uid of the curre 127 must be a cifs mount, and the uid of the current user must match the uid
128 of the user who mounted the resource. 128 of the user who mounted the resource.
129 129
130 Also note that the customary way of allowing u 130 Also note that the customary way of allowing user mounts and unmounts is
131 (instead of using mount.cifs and unmount.cifs 131 (instead of using mount.cifs and unmount.cifs as suid) to add a line
132 to the file /etc/fstab for each //server/share 132 to the file /etc/fstab for each //server/share you wish to mount, but
133 this can become unwieldy when potential mount 133 this can become unwieldy when potential mount targets include many
134 or unpredictable UNC names. 134 or unpredictable UNC names.
135 135
136 Samba Considerations 136 Samba Considerations
137 ==================== 137 ====================
138 138
139 Most current servers support SMB2.1 and SMB3 w 139 Most current servers support SMB2.1 and SMB3 which are more secure,
140 but there are useful protocol extensions for t 140 but there are useful protocol extensions for the older less secure CIFS
141 dialect, so to get the maximum benefit if moun 141 dialect, so to get the maximum benefit if mounting using the older dialect
142 (CIFS/SMB1), we recommend using a server that 142 (CIFS/SMB1), we recommend using a server that supports the SNIA CIFS
143 Unix Extensions standard (e.g. almost any ver 143 Unix Extensions standard (e.g. almost any version of Samba ie version
144 2.2.5 or later) but the CIFS vfs works fine wi 144 2.2.5 or later) but the CIFS vfs works fine with a wide variety of CIFS servers.
145 Note that uid, gid and file permissions will d 145 Note that uid, gid and file permissions will display default values if you do
146 not have a server that supports the Unix exten 146 not have a server that supports the Unix extensions for CIFS (such as Samba
147 2.2.5 or later). To enable the Unix CIFS Exte 147 2.2.5 or later). To enable the Unix CIFS Extensions in the Samba server, add
148 the line:: 148 the line::
149 149
150 unix extensions = yes 150 unix extensions = yes
151 151
152 to your smb.conf file on the server. Note tha 152 to your smb.conf file on the server. Note that the following smb.conf settings
153 are also useful (on the Samba server) when the 153 are also useful (on the Samba server) when the majority of clients are Unix or
154 Linux:: 154 Linux::
155 155
156 case sensitive = yes 156 case sensitive = yes
157 delete readonly = yes 157 delete readonly = yes
158 ea support = yes 158 ea support = yes
159 159
160 Note that server ea support is required for su 160 Note that server ea support is required for supporting xattrs from the Linux
161 cifs client, and that EA support is present in 161 cifs client, and that EA support is present in later versions of Samba (e.g.
162 3.0.6 and later (also EA support works in all 162 3.0.6 and later (also EA support works in all versions of Windows, at least to
163 shares on NTFS filesystems). Extended Attribu 163 shares on NTFS filesystems). Extended Attribute (xattr) support is an optional
164 feature of most Linux filesystems which may re 164 feature of most Linux filesystems which may require enabling via
165 make menuconfig. Client support for extended a 165 make menuconfig. Client support for extended attributes (user xattr) can be
166 disabled on a per-mount basis by specifying `` 166 disabled on a per-mount basis by specifying ``nouser_xattr`` on mount.
167 167
168 The CIFS client can get and set POSIX ACLs (ge 168 The CIFS client can get and set POSIX ACLs (getfacl, setfacl) to Samba servers
169 version 3.10 and later. Setting POSIX ACLs re 169 version 3.10 and later. Setting POSIX ACLs requires enabling both XATTR and
170 then POSIX support in the CIFS configuration o 170 then POSIX support in the CIFS configuration options when building the cifs
171 module. POSIX ACL support can be disabled on 171 module. POSIX ACL support can be disabled on a per mount basic by specifying
172 ``noacl`` on mount. 172 ``noacl`` on mount.
173 173
174 Some administrators may want to change Samba's 174 Some administrators may want to change Samba's smb.conf ``map archive`` and
175 ``create mask`` parameters from the default. 175 ``create mask`` parameters from the default. Unless the create mask is changed
176 newly created files can end up with an unneces 176 newly created files can end up with an unnecessarily restrictive default mode,
177 which may not be what you want, although if th 177 which may not be what you want, although if the CIFS Unix extensions are
178 enabled on the server and client, subsequent s 178 enabled on the server and client, subsequent setattr calls (e.g. chmod) can
179 fix the mode. Note that creating special devi 179 fix the mode. Note that creating special devices (mknod) remotely
180 may require specifying a mkdev function to Sam 180 may require specifying a mkdev function to Samba if you are not using
181 Samba 3.0.6 or later. For more information on 181 Samba 3.0.6 or later. For more information on these see the manual pages
182 (``man smb.conf``) on the Samba server system. 182 (``man smb.conf``) on the Samba server system. Note that the cifs vfs,
183 unlike the smbfs vfs, does not read the smb.co 183 unlike the smbfs vfs, does not read the smb.conf on the client system
184 (the few optional settings are passed in on mo 184 (the few optional settings are passed in on mount via -o parameters instead).
185 Note that Samba 2.2.7 or later includes a fix 185 Note that Samba 2.2.7 or later includes a fix that allows the CIFS VFS to delete
186 open files (required for strict POSIX complian 186 open files (required for strict POSIX compliance). Windows Servers already
187 supported this feature. Samba server does not 187 supported this feature. Samba server does not allow symlinks that refer to files
188 outside of the share, so in Samba versions pri 188 outside of the share, so in Samba versions prior to 3.0.6, most symlinks to
189 files with absolute paths (ie beginning with s 189 files with absolute paths (ie beginning with slash) such as::
190 190
191 ln -s /mnt/foo bar 191 ln -s /mnt/foo bar
192 192
193 would be forbidden. Samba 3.0.6 server or late 193 would be forbidden. Samba 3.0.6 server or later includes the ability to create
194 such symlinks safely by converting unsafe syml 194 such symlinks safely by converting unsafe symlinks (ie symlinks to server
195 files that are outside of the share) to a samb 195 files that are outside of the share) to a samba specific format on the server
196 that is ignored by local server applications a 196 that is ignored by local server applications and non-cifs clients and that will
197 not be traversed by the Samba server). This i 197 not be traversed by the Samba server). This is opaque to the Linux client
198 application using the cifs vfs. Absolute symli 198 application using the cifs vfs. Absolute symlinks will work to Samba 3.0.5 or
199 later, but only for remote clients using the C 199 later, but only for remote clients using the CIFS Unix extensions, and will
200 be invisible to Windows clients and typically 200 be invisible to Windows clients and typically will not affect local
201 applications running on the same server as Sam 201 applications running on the same server as Samba.
202 202
203 Use instructions 203 Use instructions
204 ================ 204 ================
205 205
206 Once the CIFS VFS support is built into the ke 206 Once the CIFS VFS support is built into the kernel or installed as a module
207 (cifs.ko), you can use mount syntax like the f 207 (cifs.ko), you can use mount syntax like the following to access Samba or
208 Mac or Windows servers:: 208 Mac or Windows servers::
209 209
210 mount -t cifs //9.53.216.11/e$ /mnt -o usern 210 mount -t cifs //9.53.216.11/e$ /mnt -o username=myname,password=mypassword
211 211
212 Before -o the option -v may be specified to ma 212 Before -o the option -v may be specified to make the mount.cifs
213 mount helper display the mount steps more verb 213 mount helper display the mount steps more verbosely.
214 After -o the following commonly used cifs vfs 214 After -o the following commonly used cifs vfs specific options
215 are supported:: 215 are supported::
216 216
217 username=<username> 217 username=<username>
218 password=<password> 218 password=<password>
219 domain=<domain name> 219 domain=<domain name>
220 220
221 Other cifs mount options are described below. 221 Other cifs mount options are described below. Use of TCP names (in addition to
222 ip addresses) is available if the mount helper 222 ip addresses) is available if the mount helper (mount.cifs) is installed. If
223 you do not trust the server to which are mount 223 you do not trust the server to which are mounted, or if you do not have
224 cifs signing enabled (and the physical network 224 cifs signing enabled (and the physical network is insecure), consider use
225 of the standard mount options ``noexec`` and ` 225 of the standard mount options ``noexec`` and ``nosuid`` to reduce the risk of
226 running an altered binary on your local system 226 running an altered binary on your local system (downloaded from a hostile server
227 or altered by a hostile router). 227 or altered by a hostile router).
228 228
229 Although mounting using format corresponding t 229 Although mounting using format corresponding to the CIFS URL specification is
230 not possible in mount.cifs yet, it is possible 230 not possible in mount.cifs yet, it is possible to use an alternate format
231 for the server and sharename (which is somewha 231 for the server and sharename (which is somewhat similar to NFS style mount
232 syntax) instead of the more widely used UNC fo 232 syntax) instead of the more widely used UNC format (i.e. \\server\share)::
233 233
234 mount -t cifs tcp_name_of_server:share_name 234 mount -t cifs tcp_name_of_server:share_name /mnt -o user=myname,pass=mypasswd
235 235
236 When using the mount helper mount.cifs, passwo 236 When using the mount helper mount.cifs, passwords may be specified via alternate
237 mechanisms, instead of specifying it after -o 237 mechanisms, instead of specifying it after -o using the normal ``pass=`` syntax
238 on the command line: 238 on the command line:
239 1) By including it in a credential file. Speci 239 1) By including it in a credential file. Specify credentials=filename as one
240 of the mount options. Credential files contain 240 of the mount options. Credential files contain two lines::
241 241
242 username=someuser 242 username=someuser
243 password=your_password 243 password=your_password
244 244
245 2) By specifying the password in the PASSWD en 245 2) By specifying the password in the PASSWD environment variable (similarly
246 the user name can be taken from the USER en 246 the user name can be taken from the USER environment variable).
247 3) By specifying the password in a file by nam 247 3) By specifying the password in a file by name via PASSWD_FILE
248 4) By specifying the password in a file by fil 248 4) By specifying the password in a file by file descriptor via PASSWD_FD
249 249
250 If no password is provided, mount.cifs will pr 250 If no password is provided, mount.cifs will prompt for password entry
251 251
252 Restrictions 252 Restrictions
253 ============ 253 ============
254 254
255 Servers must support either "pure-TCP" (port 4 255 Servers must support either "pure-TCP" (port 445 TCP/IP CIFS connections) or RFC
256 1001/1002 support for "Netbios-Over-TCP/IP." T 256 1001/1002 support for "Netbios-Over-TCP/IP." This is not likely to be a
257 problem as most servers support this. 257 problem as most servers support this.
258 258
259 Valid filenames differ between Windows and Lin 259 Valid filenames differ between Windows and Linux. Windows typically restricts
260 filenames which contain certain reserved chara 260 filenames which contain certain reserved characters (e.g.the character :
261 which is used to delimit the beginning of a st 261 which is used to delimit the beginning of a stream name by Windows), while
262 Linux allows a slightly wider set of valid cha 262 Linux allows a slightly wider set of valid characters in filenames. Windows
263 servers can remap such characters when an expl 263 servers can remap such characters when an explicit mapping is specified in
264 the Server's registry. Samba starting with ve 264 the Server's registry. Samba starting with version 3.10 will allow such
265 filenames (ie those which contain valid Linux 265 filenames (ie those which contain valid Linux characters, which normally
266 would be forbidden for Windows/CIFS semantics) 266 would be forbidden for Windows/CIFS semantics) as long as the server is
267 configured for Unix Extensions (and the client 267 configured for Unix Extensions (and the client has not disabled
268 /proc/fs/cifs/LinuxExtensionsEnabled). In addi 268 /proc/fs/cifs/LinuxExtensionsEnabled). In addition the mount option
269 ``mapposix`` can be used on CIFS (vers=1.0) to 269 ``mapposix`` can be used on CIFS (vers=1.0) to force the mapping of
270 illegal Windows/NTFS/SMB characters to a remap 270 illegal Windows/NTFS/SMB characters to a remap range (this mount parameter
271 is the default for SMB3). This remap (``mappos 271 is the default for SMB3). This remap (``mapposix``) range is also
272 compatible with Mac (and "Services for Mac" on 272 compatible with Mac (and "Services for Mac" on some older Windows).
273 273
274 CIFS VFS Mount Options 274 CIFS VFS Mount Options
275 ====================== 275 ======================
276 A partial list of the supported mount options 276 A partial list of the supported mount options follows:
277 277
278 username 278 username
279 The user name to use when tryi 279 The user name to use when trying to establish
280 the CIFS session. 280 the CIFS session.
281 password 281 password
282 The user password. If the mou 282 The user password. If the mount helper is
283 installed, the user will be pr 283 installed, the user will be prompted for password
284 if not supplied. 284 if not supplied.
285 ip 285 ip
286 The ip address of the target s 286 The ip address of the target server
287 unc 287 unc
288 The target server Universal Ne 288 The target server Universal Network Name (export) to
289 mount. 289 mount.
290 domain 290 domain
291 Set the SMB/CIFS workgroup nam 291 Set the SMB/CIFS workgroup name prepended to the
292 username during CIFS session e 292 username during CIFS session establishment
293 forceuid 293 forceuid
294 Set the default uid for inodes 294 Set the default uid for inodes to the uid
295 passed in on mount. For mounts 295 passed in on mount. For mounts to servers
296 which do support the CIFS Unix 296 which do support the CIFS Unix extensions, such as a
297 properly configured Samba serv 297 properly configured Samba server, the server provides
298 the uid, gid and mode so this 298 the uid, gid and mode so this parameter should not be
299 specified unless the server an 299 specified unless the server and clients uid and gid
300 numbering differ. If the serv 300 numbering differ. If the server and client are in the
301 same domain (e.g. running winb 301 same domain (e.g. running winbind or nss_ldap) and
302 the server supports the Unix E 302 the server supports the Unix Extensions then the uid
303 and gid can be retrieved from 303 and gid can be retrieved from the server (and uid
304 and gid would not have to be s 304 and gid would not have to be specified on the mount.
305 For servers which do not suppo 305 For servers which do not support the CIFS Unix
306 extensions, the default uid (a 306 extensions, the default uid (and gid) returned on lookup
307 of existing files will be the 307 of existing files will be the uid (gid) of the person
308 who executed the mount (root, 308 who executed the mount (root, except when mount.cifs
309 is configured setuid for user 309 is configured setuid for user mounts) unless the ``uid=``
310 (gid) mount option is specifie 310 (gid) mount option is specified. Also note that permission
311 checks (authorization checks) 311 checks (authorization checks) on accesses to a file occur
312 at the server, but there are c 312 at the server, but there are cases in which an administrator
313 may want to restrict at the cl 313 may want to restrict at the client as well. For those
314 servers which do not report a 314 servers which do not report a uid/gid owner
315 (such as Windows), permissions 315 (such as Windows), permissions can also be checked at the
316 client, and a crude form of cl 316 client, and a crude form of client side permission checking
317 can be enabled by specifying f 317 can be enabled by specifying file_mode and dir_mode on
318 the client. (default) 318 the client. (default)
319 forcegid 319 forcegid
320 (similar to above but for the 320 (similar to above but for the groupid instead of uid) (default)
321 noforceuid 321 noforceuid
322 Fill in file owner information 322 Fill in file owner information (uid) by requesting it from
323 the server if possible. With t 323 the server if possible. With this option, the value given in
324 the uid= option (on mount) wil 324 the uid= option (on mount) will only be used if the server
325 can not support returning uids 325 can not support returning uids on inodes.
326 noforcegid 326 noforcegid
327 (similar to above but for the 327 (similar to above but for the group owner, gid, instead of uid)
328 uid 328 uid
329 Set the default uid for inodes 329 Set the default uid for inodes, and indicate to the
330 cifs kernel driver which local 330 cifs kernel driver which local user mounted. If the server
331 supports the unix extensions t 331 supports the unix extensions the default uid is
332 not used to fill in the owner 332 not used to fill in the owner fields of inodes (files)
333 unless the ``forceuid`` parame 333 unless the ``forceuid`` parameter is specified.
334 gid 334 gid
335 Set the default gid for inodes 335 Set the default gid for inodes (similar to above).
336 file_mode 336 file_mode
337 If CIFS Unix extensions are no 337 If CIFS Unix extensions are not supported by the server
338 this overrides the default mod 338 this overrides the default mode for file inodes.
339 fsc 339 fsc
340 Enable local disk caching usin 340 Enable local disk caching using FS-Cache (off by default). This
341 option could be useful to impr 341 option could be useful to improve performance on a slow link,
342 heavily loaded server and/or n 342 heavily loaded server and/or network where reading from the
343 disk is faster than reading fr 343 disk is faster than reading from the server (over the network).
344 This could also impact scalabi 344 This could also impact scalability positively as the
345 number of calls to the server 345 number of calls to the server are reduced. However, local
346 caching is not suitable for al 346 caching is not suitable for all workloads for e.g. read-once
347 type workloads. So, you need t 347 type workloads. So, you need to consider carefully your
348 workload/scenario before using 348 workload/scenario before using this option. Currently, local
349 disk caching is functional for 349 disk caching is functional for CIFS files opened as read-only.
350 dir_mode 350 dir_mode
351 If CIFS Unix extensions are no 351 If CIFS Unix extensions are not supported by the server
352 this overrides the default mod 352 this overrides the default mode for directory inodes.
353 port 353 port
354 attempt to contact the server 354 attempt to contact the server on this tcp port, before
355 trying the usual ports (port 4 355 trying the usual ports (port 445, then 139).
356 iocharset 356 iocharset
357 Codepage used to convert local 357 Codepage used to convert local path names to and from
358 Unicode. Unicode is used by de 358 Unicode. Unicode is used by default for network path
359 names if the server supports i 359 names if the server supports it. If iocharset is
360 not specified then the nls_def 360 not specified then the nls_default specified
361 during the local client kernel 361 during the local client kernel build will be used.
362 If server does not support Uni 362 If server does not support Unicode, this parameter is
363 unused. 363 unused.
364 rsize 364 rsize
365 default read size (usually 16K 365 default read size (usually 16K). The client currently
366 can not use rsize larger than 366 can not use rsize larger than CIFSMaxBufSize. CIFSMaxBufSize
367 defaults to 16K and may be cha 367 defaults to 16K and may be changed (from 8K to the maximum
368 kmalloc size allowed by your k 368 kmalloc size allowed by your kernel) at module install time
369 for cifs.ko. Setting CIFSMaxBu 369 for cifs.ko. Setting CIFSMaxBufSize to a very large value
370 will cause cifs to use more me 370 will cause cifs to use more memory and may reduce performance
371 in some cases. To use rsize g 371 in some cases. To use rsize greater than 127K (the original
372 cifs protocol maximum) also re 372 cifs protocol maximum) also requires that the server support
373 a new Unix Capability flag (fo 373 a new Unix Capability flag (for very large read) which some
374 newer servers (e.g. Samba 3.0. 374 newer servers (e.g. Samba 3.0.26 or later) do. rsize can be
375 set from a minimum of 2048 to 375 set from a minimum of 2048 to a maximum of 130048 (127K or
376 CIFSMaxBufSize, whichever is s 376 CIFSMaxBufSize, whichever is smaller)
377 wsize 377 wsize
378 default write size (default 57 378 default write size (default 57344)
379 maximum wsize currently allowe 379 maximum wsize currently allowed by CIFS is 57344 (fourteen
380 4096 byte pages) 380 4096 byte pages)
381 actimeo=n 381 actimeo=n
382 attribute cache timeout in sec 382 attribute cache timeout in seconds (default 1 second).
383 After this timeout, the cifs c 383 After this timeout, the cifs client requests fresh attribute
384 information from the server. T 384 information from the server. This option allows to tune the
385 attribute cache timeout to sui 385 attribute cache timeout to suit the workload needs. Shorter
386 timeouts mean better the cache 386 timeouts mean better the cache coherency, but increased number
387 of calls to the server. Longer 387 of calls to the server. Longer timeouts mean reduced number
388 of calls to the server at the 388 of calls to the server at the expense of less stricter cache
389 coherency checks (i.e. incorre 389 coherency checks (i.e. incorrect attribute cache for a short
390 period of time). 390 period of time).
391 rw 391 rw
392 mount the network share read-w 392 mount the network share read-write (note that the
393 server may still consider the 393 server may still consider the share read-only)
394 ro 394 ro
395 mount network share read-only 395 mount network share read-only
396 version 396 version
397 used to distinguish different 397 used to distinguish different versions of the
398 mount helper utility (not typi 398 mount helper utility (not typically needed)
399 sep 399 sep
400 if first mount option (after t 400 if first mount option (after the -o), overrides
401 the comma as the separator bet 401 the comma as the separator between the mount
402 parameters. e.g.:: 402 parameters. e.g.::
403 403
404 -o user=myname,passwor 404 -o user=myname,password=mypassword,domain=mydom
405 405
406 could be passed instead with p 406 could be passed instead with period as the separator by::
407 407
408 -o sep=.user=myname.pa 408 -o sep=.user=myname.password=mypassword.domain=mydom
409 409
410 this might be useful when comm 410 this might be useful when comma is contained within username
411 or password or domain. This op 411 or password or domain. This option is less important
412 when the cifs mount helper cif 412 when the cifs mount helper cifs.mount (version 1.1 or later)
413 is used. 413 is used.
414 nosuid 414 nosuid
415 Do not allow remote executable 415 Do not allow remote executables with the suid bit
416 program to be executed. This 416 program to be executed. This is only meaningful for mounts
417 to servers such as Samba which 417 to servers such as Samba which support the CIFS Unix Extensions.
418 If you do not trust the server 418 If you do not trust the servers in your network (your mount
419 targets) it is recommended tha 419 targets) it is recommended that you specify this option for
420 greater security. 420 greater security.
421 exec 421 exec
422 Permit execution of binaries o 422 Permit execution of binaries on the mount.
423 noexec 423 noexec
424 Do not permit execution of bin 424 Do not permit execution of binaries on the mount.
425 dev 425 dev
426 Recognize block devices on the 426 Recognize block devices on the remote mount.
427 nodev 427 nodev
428 Do not recognize devices on th 428 Do not recognize devices on the remote mount.
429 suid 429 suid
430 Allow remote files on this mou 430 Allow remote files on this mountpoint with suid enabled to
431 be executed (default for mount 431 be executed (default for mounts when executed as root,
432 nosuid is default for user mou 432 nosuid is default for user mounts).
433 credentials 433 credentials
434 Although ignored by the cifs k 434 Although ignored by the cifs kernel component, it is used by
435 the mount helper, mount.cifs. 435 the mount helper, mount.cifs. When mount.cifs is installed it
436 opens and reads the credential 436 opens and reads the credential file specified in order
437 to obtain the userid and passw 437 to obtain the userid and password arguments which are passed to
438 the cifs vfs. 438 the cifs vfs.
439 guest 439 guest
440 Although ignored by the kernel 440 Although ignored by the kernel component, the mount.cifs
441 mount helper will not prompt t 441 mount helper will not prompt the user for a password
442 if guest is specified on the m 442 if guest is specified on the mount options. If no
443 password is specified a null p 443 password is specified a null password will be used.
444 perm 444 perm
445 Client does permission checks 445 Client does permission checks (vfs_permission check of uid
446 and gid of the file against th 446 and gid of the file against the mode and desired operation),
447 Note that this is in addition 447 Note that this is in addition to the normal ACL check on the
448 target machine done by the ser 448 target machine done by the server software.
449 Client permission checking is 449 Client permission checking is enabled by default.
450 noperm 450 noperm
451 Client does not do permission 451 Client does not do permission checks. This can expose
452 files on this mount to access 452 files on this mount to access by other users on the local
453 client system. It is typically 453 client system. It is typically only needed when the server
454 supports the CIFS Unix Extensi 454 supports the CIFS Unix Extensions but the UIDs/GIDs on the
455 client and server system do no 455 client and server system do not match closely enough to allow
456 access by the user doing the m 456 access by the user doing the mount, but it may be useful with
457 non CIFS Unix Extension mounts 457 non CIFS Unix Extension mounts for cases in which the default
458 mode is specified on the mount 458 mode is specified on the mount but is not to be enforced on the
459 client (e.g. perhaps when Mult 459 client (e.g. perhaps when MultiUserMount is enabled)
460 Note that this does not affect 460 Note that this does not affect the normal ACL check on the
461 target machine done by the ser 461 target machine done by the server software (of the server
462 ACL against the user name prov 462 ACL against the user name provided at mount time).
463 serverino 463 serverino
464 Use server's inode numbers ins 464 Use server's inode numbers instead of generating automatically
465 incrementing inode numbers on 465 incrementing inode numbers on the client. Although this will
466 make it easier to spot hardlin 466 make it easier to spot hardlinked files (as they will have
467 the same inode numbers) and in 467 the same inode numbers) and inode numbers may be persistent,
468 note that the server does not 468 note that the server does not guarantee that the inode numbers
469 are unique if multiple server 469 are unique if multiple server side mounts are exported under a
470 single share (since inode numb 470 single share (since inode numbers on the servers might not
471 be unique if multiple filesyst 471 be unique if multiple filesystems are mounted under the same
472 shared higher level directory) 472 shared higher level directory). Note that some older
473 (e.g. pre-Windows 2000) do not 473 (e.g. pre-Windows 2000) do not support returning UniqueIDs
474 or the CIFS Unix Extensions eq 474 or the CIFS Unix Extensions equivalent and for those
475 this mount option will have no 475 this mount option will have no effect. Exporting cifs mounts
476 under nfsd requires this mount 476 under nfsd requires this mount option on the cifs mount.
477 This is now the default if ser 477 This is now the default if server supports the
478 required network operation. 478 required network operation.
479 noserverino 479 noserverino
480 Client generates inode numbers 480 Client generates inode numbers (rather than using the actual one
481 from the server). These inode 481 from the server). These inode numbers will vary after
482 unmount or reboot which can co 482 unmount or reboot which can confuse some applications,
483 but not all server filesystems 483 but not all server filesystems support unique inode
484 numbers. 484 numbers.
485 setuids 485 setuids
486 If the CIFS Unix extensions ar 486 If the CIFS Unix extensions are negotiated with the server
487 the client will attempt to set 487 the client will attempt to set the effective uid and gid of
488 the local process on newly cre 488 the local process on newly created files, directories, and
489 devices (create, mkdir, mknod) 489 devices (create, mkdir, mknod). If the CIFS Unix Extensions
490 are not negotiated, for newly 490 are not negotiated, for newly created files and directories
491 instead of using the default u 491 instead of using the default uid and gid specified on
492 the mount, cache the new file' 492 the mount, cache the new file's uid and gid locally which means
493 that the uid for the file can 493 that the uid for the file can change when the inode is
494 reloaded (or the user remounts 494 reloaded (or the user remounts the share).
495 nosetuids 495 nosetuids
496 The client will not attempt to 496 The client will not attempt to set the uid and gid on
497 on newly created files, direct 497 on newly created files, directories, and devices (create,
498 mkdir, mknod) which will resul 498 mkdir, mknod) which will result in the server setting the
499 uid and gid to the default (us 499 uid and gid to the default (usually the server uid of the
500 user who mounted the share). 500 user who mounted the share). Letting the server (rather than
501 the client) set the uid and gi 501 the client) set the uid and gid is the default. If the CIFS
502 Unix Extensions are not negoti 502 Unix Extensions are not negotiated then the uid and gid for
503 new files will appear to be th 503 new files will appear to be the uid (gid) of the mounter or the
504 uid (gid) parameter specified 504 uid (gid) parameter specified on the mount.
505 netbiosname 505 netbiosname
506 When mounting to servers via p 506 When mounting to servers via port 139, specifies the RFC1001
507 source name to use to represen 507 source name to use to represent the client netbios machine
508 name when doing the RFC1001 ne 508 name when doing the RFC1001 netbios session initialize.
509 direct 509 direct
510 Do not do inode data caching o 510 Do not do inode data caching on files opened on this mount.
511 This precludes mmapping files 511 This precludes mmapping files on this mount. In some cases
512 with fast networks and little 512 with fast networks and little or no caching benefits on the
513 client (e.g. when the applicat 513 client (e.g. when the application is doing large sequential
514 reads bigger than page size wi 514 reads bigger than page size without rereading the same data)
515 this can provide better perfor 515 this can provide better performance than the default
516 behavior which caches reads (r 516 behavior which caches reads (readahead) and writes
517 (writebehind) through the loca 517 (writebehind) through the local Linux client pagecache
518 if oplock (caching token) is g 518 if oplock (caching token) is granted and held. Note that
519 direct allows write operations 519 direct allows write operations larger than page size
520 to be sent to the server. 520 to be sent to the server.
521 strictcache 521 strictcache
522 Use for switching on strict ca 522 Use for switching on strict cache mode. In this mode the
523 client read from the cache all 523 client read from the cache all the time it has Oplock Level II,
524 otherwise - read from the serv 524 otherwise - read from the server. All written data are stored
525 in the cache, but if the clien 525 in the cache, but if the client doesn't have Exclusive Oplock,
526 it writes the data to the serv 526 it writes the data to the server.
527 rwpidforward 527 rwpidforward
528 Forward pid of a process who o 528 Forward pid of a process who opened a file to any read or write
529 operation on that file. This p 529 operation on that file. This prevent applications like WINE
530 from failing on read and write 530 from failing on read and write if we use mandatory brlock style.
531 acl 531 acl
532 Allow setfacl and getfacl to m 532 Allow setfacl and getfacl to manage posix ACLs if server
533 supports them. (default) 533 supports them. (default)
534 noacl 534 noacl
535 Do not allow setfacl and getfa 535 Do not allow setfacl and getfacl calls on this mount
536 user_xattr 536 user_xattr
537 Allow getting and setting user 537 Allow getting and setting user xattrs (those attributes whose
538 name begins with ``user.`` or 538 name begins with ``user.`` or ``os2.``) as OS/2 EAs (extended
539 attributes) to the server. Th 539 attributes) to the server. This allows support of the
540 setfattr and getfattr utilitie 540 setfattr and getfattr utilities. (default)
541 nouser_xattr 541 nouser_xattr
542 Do not allow getfattr/setfattr 542 Do not allow getfattr/setfattr to get/set/list xattrs
543 mapchars 543 mapchars
544 Translate six of the seven res 544 Translate six of the seven reserved characters (not backslash)::
545 545
546 *?<>|: 546 *?<>|:
547 547
548 to the remap range (above 0xF0 548 to the remap range (above 0xF000), which also
549 allows the CIFS client to reco 549 allows the CIFS client to recognize files created with
550 such characters by Windows's P 550 such characters by Windows's POSIX emulation. This can
551 also be useful when mounting t 551 also be useful when mounting to most versions of Samba
552 (which also forbids creating a 552 (which also forbids creating and opening files
553 whose names contain any of the 553 whose names contain any of these seven characters).
554 This has no effect if the serv 554 This has no effect if the server does not support
555 Unicode on the wire. 555 Unicode on the wire.
556 nomapchars 556 nomapchars
557 Do not translate any of these 557 Do not translate any of these seven characters (default).
558 nocase 558 nocase
559 Request case insensitive path 559 Request case insensitive path name matching (case
560 sensitive is the default if th 560 sensitive is the default if the server supports it).
561 (mount option ``ignorecase`` i 561 (mount option ``ignorecase`` is identical to ``nocase``)
562 posixpaths 562 posixpaths
563 If CIFS Unix extensions are su 563 If CIFS Unix extensions are supported, attempt to
564 negotiate posix path name supp 564 negotiate posix path name support which allows certain
565 characters forbidden in typica 565 characters forbidden in typical CIFS filenames, without
566 requiring remapping. (default) 566 requiring remapping. (default)
567 noposixpaths 567 noposixpaths
568 If CIFS Unix extensions are su 568 If CIFS Unix extensions are supported, do not request
569 posix path name support (this 569 posix path name support (this may cause servers to
570 reject creatingfile with certa 570 reject creatingfile with certain reserved characters).
571 nounix 571 nounix
572 Disable the CIFS Unix Extensio 572 Disable the CIFS Unix Extensions for this mount (tree
573 connection). This is rarely ne 573 connection). This is rarely needed, but it may be useful
574 in order to turn off multiple 574 in order to turn off multiple settings all at once (ie
575 posix acls, posix locks, posix 575 posix acls, posix locks, posix paths, symlink support
576 and retrieving uids/gids/mode 576 and retrieving uids/gids/mode from the server) or to
577 work around a bug in server wh 577 work around a bug in server which implement the Unix
578 Extensions. 578 Extensions.
579 nobrl 579 nobrl
580 Do not send byte range lock re 580 Do not send byte range lock requests to the server.
581 This is necessary for certain 581 This is necessary for certain applications that break
582 with cifs style mandatory byte 582 with cifs style mandatory byte range locks (and most
583 cifs servers do not yet suppor 583 cifs servers do not yet support requesting advisory
584 byte range locks). 584 byte range locks).
585 forcemandatorylock 585 forcemandatorylock
586 Even if the server supports po 586 Even if the server supports posix (advisory) byte range
587 locking, send only mandatory l 587 locking, send only mandatory lock requests. For some
588 (presumably rare) applications 588 (presumably rare) applications, originally coded for
589 DOS/Windows, which require Win 589 DOS/Windows, which require Windows style mandatory byte range
590 locking, they may be able to t 590 locking, they may be able to take advantage of this option,
591 forcing the cifs client to onl 591 forcing the cifs client to only send mandatory locks
592 even if the cifs server would 592 even if the cifs server would support posix advisory locks.
593 ``forcemand`` is accepted as a 593 ``forcemand`` is accepted as a shorter form of this mount
594 option. 594 option.
595 nostrictsync 595 nostrictsync
596 If this mount option is set, w 596 If this mount option is set, when an application does an
597 fsync call then the cifs clien 597 fsync call then the cifs client does not send an SMB Flush
598 to the server (to force the se 598 to the server (to force the server to write all dirty data
599 for this file immediately to d 599 for this file immediately to disk), although cifs still sends
600 all dirty (cached) file data t 600 all dirty (cached) file data to the server and waits for the
601 server to respond to the write 601 server to respond to the write. Since SMB Flush can be
602 very slow, and some servers ma 602 very slow, and some servers may be reliable enough (to risk
603 delaying slightly flushing the 603 delaying slightly flushing the data to disk on the server),
604 turning on this option may be 604 turning on this option may be useful to improve performance for
605 applications that fsync too mu 605 applications that fsync too much, at a small risk of server
606 crash. If this mount option i 606 crash. If this mount option is not set, by default cifs will
607 send an SMB flush request (and 607 send an SMB flush request (and wait for a response) on every
608 fsync call. 608 fsync call.
609 nodfs 609 nodfs
610 Disable DFS (global name space 610 Disable DFS (global name space support) even if the
611 server claims to support it. 611 server claims to support it. This can help work around
612 a problem with parsing of DFS 612 a problem with parsing of DFS paths with Samba server
613 versions 3.0.24 and 3.0.25. 613 versions 3.0.24 and 3.0.25.
614 remount 614 remount
615 remount the share (often used 615 remount the share (often used to change from ro to rw mounts
616 or vice versa) 616 or vice versa)
617 cifsacl 617 cifsacl
618 Report mode bits (e.g. on stat 618 Report mode bits (e.g. on stat) based on the Windows ACL for
619 the file. (EXPERIMENTAL) 619 the file. (EXPERIMENTAL)
620 servern 620 servern
621 Specify the server 's netbios 621 Specify the server 's netbios name (RFC1001 name) to use
622 when attempting to setup a ses 622 when attempting to setup a session to the server.
623 This is needed for mounting to 623 This is needed for mounting to some older servers (such
624 as OS/2 or Windows 98 and Wind 624 as OS/2 or Windows 98 and Windows ME) since they do not
625 support a default server name. 625 support a default server name. A server name can be up
626 to 15 characters long and is u 626 to 15 characters long and is usually uppercased.
627 sfu 627 sfu
628 When the CIFS Unix Extensions 628 When the CIFS Unix Extensions are not negotiated, attempt to
629 create device files and fifos 629 create device files and fifos in a format compatible with
630 Services for Unix (SFU). In a 630 Services for Unix (SFU). In addition retrieve bits 10-12
631 of the mode via the SETFILEBIT 631 of the mode via the SETFILEBITS extended attribute (as
632 SFU does). In the future the 632 SFU does). In the future the bottom 9 bits of the
633 mode also will be emulated usi 633 mode also will be emulated using queries of the security
634 descriptor (ACL). 634 descriptor (ACL).
635 mfsymlinks 635 mfsymlinks
636 Enable support for Minshall+Fr 636 Enable support for Minshall+French symlinks
637 (see http://wiki.samba.org/ind 637 (see http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks)
638 This option is ignored when sp 638 This option is ignored when specified together with the
639 'sfu' option. Minshall+French 639 'sfu' option. Minshall+French symlinks are used even if
640 the server supports the CIFS U 640 the server supports the CIFS Unix Extensions.
641 sign 641 sign
642 Must use packet signing (helps 642 Must use packet signing (helps avoid unwanted data modification
643 by intermediate systems in the 643 by intermediate systems in the route). Note that signing
644 does not work with lanman or p 644 does not work with lanman or plaintext authentication.
645 seal 645 seal
646 Must seal (encrypt) all data o 646 Must seal (encrypt) all data on this mounted share before
647 sending on the network. Requi 647 sending on the network. Requires support for Unix Extensions.
648 Note that this differs from th 648 Note that this differs from the sign mount option in that it
649 causes encryption of data sent 649 causes encryption of data sent over this mounted share but other
650 shares mounted to the same ser 650 shares mounted to the same server are unaffected.
651 locallease 651 locallease
652 This option is rarely needed. 652 This option is rarely needed. Fcntl F_SETLEASE is
653 used by some applications such 653 used by some applications such as Samba and NFSv4 server to
654 check to see whether a file is 654 check to see whether a file is cacheable. CIFS has no way
655 to explicitly request a lease, 655 to explicitly request a lease, but can check whether a file
656 is cacheable (oplocked). Unfo 656 is cacheable (oplocked). Unfortunately, even if a file
657 is not oplocked, it could stil 657 is not oplocked, it could still be cacheable (ie cifs client
658 could grant fcntl leases if no 658 could grant fcntl leases if no other local processes are using
659 the file) for cases for exampl 659 the file) for cases for example such as when the server does not
660 support oplocks and the user i 660 support oplocks and the user is sure that the only updates to
661 the file will be from this cli 661 the file will be from this client. Specifying this mount option
662 will allow the cifs client to 662 will allow the cifs client to check for leases (only) locally
663 for files which are not oplock 663 for files which are not oplocked instead of denying leases
664 in that case. (EXPERIMENTAL) 664 in that case. (EXPERIMENTAL)
665 sec 665 sec
666 Security mode. Allowed values 666 Security mode. Allowed values are:
667 667
668 none 668 none
669 attempt to con 669 attempt to connection as a null user (no name)
670 krb5 670 krb5
671 Use Kerberos v 671 Use Kerberos version 5 authentication
672 krb5i 672 krb5i
673 Use Kerberos a 673 Use Kerberos authentication and packet signing
674 ntlm 674 ntlm
675 Use NTLM passw 675 Use NTLM password hashing (default)
676 ntlmi 676 ntlmi
677 Use NTLM passw 677 Use NTLM password hashing with signing (if
678 /proc/fs/cifs/ 678 /proc/fs/cifs/PacketSigningEnabled on or if
679 server require 679 server requires signing also can be the default)
680 ntlmv2 680 ntlmv2
681 Use NTLMv2 pas 681 Use NTLMv2 password hashing
682 ntlmv2i 682 ntlmv2i
683 Use NTLMv2 pas 683 Use NTLMv2 password hashing with packet signing
684 lanman 684 lanman
685 (if configured 685 (if configured in kernel config) use older
686 lanman hash 686 lanman hash
687 hard 687 hard
688 Retry file operations if serve 688 Retry file operations if server is not responding
689 soft 689 soft
690 Limit retries to unresponsive 690 Limit retries to unresponsive servers (usually only
691 one retry) before returning an 691 one retry) before returning an error. (default)
692 692
693 The mount.cifs mount helper also accepts a few 693 The mount.cifs mount helper also accepts a few mount options before -o
694 including: 694 including:
695 695
696 =============== ============================== 696 =============== ===============================================================
697 -S take password from stdin (equi 697 -S take password from stdin (equivalent to setting the environment
698 variable ``PASSWD_FD=0`` 698 variable ``PASSWD_FD=0``
699 -V print mount.cifs version 699 -V print mount.cifs version
700 -? display simple usage informati 700 -? display simple usage information
701 =============== ============================== 701 =============== ===============================================================
702 702
703 With most 2.6 kernel versions of modutils, the 703 With most 2.6 kernel versions of modutils, the version of the cifs kernel
704 module can be displayed via modinfo. 704 module can be displayed via modinfo.
705 705
706 Misc /proc/fs/cifs Flags and Debug Info 706 Misc /proc/fs/cifs Flags and Debug Info
707 ======================================= 707 =======================================
708 708
709 Informational pseudo-files: 709 Informational pseudo-files:
710 710
711 ======================= ====================== 711 ======================= =======================================================
712 DebugData Displays information a 712 DebugData Displays information about active CIFS sessions and
713 shares, features enabl 713 shares, features enabled as well as the cifs.ko
714 version. 714 version.
715 Stats Lists summary resource 715 Stats Lists summary resource usage information as well as per
716 share statistics. 716 share statistics.
717 open_files List all the open file 717 open_files List all the open file handles on all active SMB sessions.
718 mount_params List of all mount para 718 mount_params List of all mount parameters available for the module
719 ======================= ====================== 719 ======================= =======================================================
720 720
721 Configuration pseudo-files: 721 Configuration pseudo-files:
722 722
723 ======================= ====================== 723 ======================= =======================================================
724 SecurityFlags Flags which control se 724 SecurityFlags Flags which control security negotiation and
725 also packet signing. A 725 also packet signing. Authentication (may/must)
726 flags (e.g. for NTLMv2 726 flags (e.g. for NTLMv2) may be combined with
727 the signing flags. Sp 727 the signing flags. Specifying two different password
728 hashing mechanisms (as 728 hashing mechanisms (as "must use") on the other hand
729 does not make much sen 729 does not make much sense. Default flags are::
730 730
731 0x00C5 731 0x00C5
732 732
733 (NTLMv2 and packet sig 733 (NTLMv2 and packet signing allowed). Some SecurityFlags
734 may require enabling a 734 may require enabling a corresponding menuconfig option.
735 735
736 may use packet signi 736 may use packet signing 0x00001
737 must use packet sign 737 must use packet signing 0x01001
738 may use NTLMv2 738 may use NTLMv2 0x00004
739 must use NTLMv2 739 must use NTLMv2 0x04004
740 may use Kerberos sec 740 may use Kerberos security (krb5) 0x00008
741 must use Kerberos 741 must use Kerberos 0x08008
742 may use NTLMSSP 742 may use NTLMSSP 0x00080
743 must use NTLMSSP 743 must use NTLMSSP 0x80080
744 seal (packet encrypt 744 seal (packet encryption) 0x00040
745 must seal 745 must seal 0x40040
746 746
747 cifsFYI If set to non-zero val 747 cifsFYI If set to non-zero value, additional debug information
748 will be logged to the 748 will be logged to the system error log. This field
749 contains three flags c 749 contains three flags controlling different classes of
750 debugging entries. Th 750 debugging entries. The maximum value it can be set
751 to is 7 which enables 751 to is 7 which enables all debugging points (default 0).
752 Some debugging stateme 752 Some debugging statements are not compiled into the
753 cifs kernel unless CON 753 cifs kernel unless CONFIG_CIFS_DEBUG2 is enabled in the
754 kernel configuration. 754 kernel configuration. cifsFYI may be set to one or
755 more of the following 755 more of the following flags (7 sets them all)::
756 756
757 +------------------- 757 +-----------------------------------------------+------+
758 | log cifs informati 758 | log cifs informational messages | 0x01 |
759 +------------------- 759 +-----------------------------------------------+------+
760 | log return codes f 760 | log return codes from cifs entry points | 0x02 |
761 +------------------- 761 +-----------------------------------------------+------+
762 | log slow responses 762 | log slow responses | 0x04 |
763 | (ie which take lon 763 | (ie which take longer than 1 second) | |
764 | 764 | | |
765 | CONFIG_CIFS_STATS2 765 | CONFIG_CIFS_STATS2 must be enabled in .config | |
766 +------------------- 766 +-----------------------------------------------+------+
767 767
768 traceSMB If set to one, debug i 768 traceSMB If set to one, debug information is logged to the
769 system error log with 769 system error log with the start of smb requests
770 and responses (default 770 and responses (default 0)
771 LookupCacheEnable If set to one, inode i 771 LookupCacheEnable If set to one, inode information is kept cached
772 for one second improvi 772 for one second improving performance of lookups
773 (default 1) 773 (default 1)
774 LinuxExtensionsEnabled If set to one then the 774 LinuxExtensionsEnabled If set to one then the client will attempt to
775 use the CIFS "UNIX" ex 775 use the CIFS "UNIX" extensions which are optional
776 protocol enhancements 776 protocol enhancements that allow CIFS servers
777 to return accurate UID 777 to return accurate UID/GID information as well
778 as support symbolic li 778 as support symbolic links. If you use servers
779 such as Samba that sup 779 such as Samba that support the CIFS Unix
780 extensions but do not 780 extensions but do not want to use symbolic link
781 support and want to ma 781 support and want to map the uid and gid fields
782 to values supplied at 782 to values supplied at mount (rather than the
783 actual values, then se 783 actual values, then set this to zero. (default 1)
784 dfscache List the content of th 784 dfscache List the content of the DFS cache.
785 If set to 0, the clien 785 If set to 0, the client will clear the cache.
786 ======================= ====================== 786 ======================= =======================================================
787 787
788 These experimental features and tracing can be 788 These experimental features and tracing can be enabled by changing flags in
789 /proc/fs/cifs (after the cifs module has been 789 /proc/fs/cifs (after the cifs module has been installed or built into the
790 kernel, e.g. insmod cifs). To enable a featu 790 kernel, e.g. insmod cifs). To enable a feature set it to 1 e.g. to enable
791 tracing to the kernel message log type:: 791 tracing to the kernel message log type::
792 792
793 echo 7 > /proc/fs/cifs/cifsFYI 793 echo 7 > /proc/fs/cifs/cifsFYI
794 794
795 cifsFYI functions as a bit mask. Setting it to 795 cifsFYI functions as a bit mask. Setting it to 1 enables additional kernel
796 logging of various informational messages. 2 796 logging of various informational messages. 2 enables logging of non-zero
797 SMB return codes while 4 enables logging of re 797 SMB return codes while 4 enables logging of requests that take longer
798 than one second to complete (except for byte r 798 than one second to complete (except for byte range lock requests).
799 Setting it to 4 requires CONFIG_CIFS_STATS2 to 799 Setting it to 4 requires CONFIG_CIFS_STATS2 to be set in kernel configuration
800 (.config). Setting it to seven enables all thr 800 (.config). Setting it to seven enables all three. Finally, tracing
801 the start of smb requests and responses can be 801 the start of smb requests and responses can be enabled via::
802 802
803 echo 1 > /proc/fs/cifs/traceSMB 803 echo 1 > /proc/fs/cifs/traceSMB
804 804
805 Per share (per client mount) statistics are av 805 Per share (per client mount) statistics are available in /proc/fs/cifs/Stats.
806 Additional information is available if CONFIG_ 806 Additional information is available if CONFIG_CIFS_STATS2 is enabled in the
807 kernel configuration (.config). The statistic 807 kernel configuration (.config). The statistics returned include counters which
808 represent the number of attempted and failed ( 808 represent the number of attempted and failed (ie non-zero return code from the
809 server) SMB3 (or cifs) requests grouped by req 809 server) SMB3 (or cifs) requests grouped by request type (read, write, close etc.).
810 Also recorded is the total bytes read and byte 810 Also recorded is the total bytes read and bytes written to the server for
811 that share. Note that due to client caching e 811 that share. Note that due to client caching effects this can be less than the
812 number of bytes read and written by the applic 812 number of bytes read and written by the application running on the client.
813 Statistics can be reset to zero by ``echo 0 > 813 Statistics can be reset to zero by ``echo 0 > /proc/fs/cifs/Stats`` which may be
814 useful if comparing performance of two differe 814 useful if comparing performance of two different scenarios.
815 815
816 Also note that ``cat /proc/fs/cifs/DebugData`` 816 Also note that ``cat /proc/fs/cifs/DebugData`` will display information about
817 the active sessions and the shares that are mo 817 the active sessions and the shares that are mounted.
818 818
819 Enabling Kerberos (extended security) works bu 819 Enabling Kerberos (extended security) works but requires version 1.2 or later
820 of the helper program cifs.upcall to be presen 820 of the helper program cifs.upcall to be present and to be configured in the
821 /etc/request-key.conf file. The cifs.upcall h 821 /etc/request-key.conf file. The cifs.upcall helper program is from the Samba
822 project(https://www.samba.org). NTLM and NTLMv 822 project(https://www.samba.org). NTLM and NTLMv2 and LANMAN support do not
823 require this helper. Note that NTLMv2 security 823 require this helper. Note that NTLMv2 security (which does not require the
824 cifs.upcall helper program), instead of using 824 cifs.upcall helper program), instead of using Kerberos, is sufficient for
825 some use cases. 825 some use cases.
826 826
827 DFS support allows transparent redirection to 827 DFS support allows transparent redirection to shares in an MS-DFS name space.
828 In addition, DFS support for target shares whi 828 In addition, DFS support for target shares which are specified as UNC
829 names which begin with host names (rather than 829 names which begin with host names (rather than IP addresses) requires
830 a user space helper (such as cifs.upcall) to b 830 a user space helper (such as cifs.upcall) to be present in order to
831 translate host names to ip address, and the us 831 translate host names to ip address, and the user space helper must also
832 be configured in the file /etc/request-key.con 832 be configured in the file /etc/request-key.conf. Samba, Windows servers and
833 many NAS appliances support DFS as a way of co 833 many NAS appliances support DFS as a way of constructing a global name
834 space to ease network configuration and improv 834 space to ease network configuration and improve reliability.
835 835
836 To use cifs Kerberos and DFS support, the Linu 836 To use cifs Kerberos and DFS support, the Linux keyutils package should be
837 installed and something like the following lin 837 installed and something like the following lines should be added to the
838 /etc/request-key.conf file:: 838 /etc/request-key.conf file::
839 839
840 create cifs.spnego * * /usr/local/sbin/cifs. 840 create cifs.spnego * * /usr/local/sbin/cifs.upcall %k
841 create dns_resolver * * /usr/local/sbin/cifs 841 create dns_resolver * * /usr/local/sbin/cifs.upcall %k
842 842
843 CIFS kernel module parameters 843 CIFS kernel module parameters
844 ============================= 844 =============================
845 These module parameters can be specified or mo 845 These module parameters can be specified or modified either during the time of
846 module loading or during the runtime by using 846 module loading or during the runtime by using the interface::
847 847
848 /sys/module/cifs/parameters/<param> 848 /sys/module/cifs/parameters/<param>
849 849
850 i.e.:: 850 i.e.::
851 851
852 echo "value" > /sys/module/cifs/parameters 852 echo "value" > /sys/module/cifs/parameters/<param>
853 853
854 More detailed descriptions of the available mo 854 More detailed descriptions of the available module parameters and their values
855 can be seen by doing: 855 can be seen by doing:
856 856
857 modinfo cifs (or modinfo smb3) 857 modinfo cifs (or modinfo smb3)
858 858
859 ================= ============================ 859 ================= ==========================================================
860 1. enable_oplocks Enable or disable oplocks. O 860 1. enable_oplocks Enable or disable oplocks. Oplocks are enabled by default.
861 [Y/y/1]. To disable use any 861 [Y/y/1]. To disable use any of [N/n/0].
862 ================= ============================ 862 ================= ==========================================================
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