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 http://protocolfreedom.org/ and
>> 20 http://samba.org/samba/PFIF/
20 for more details. 21 for more details.
21 22
22 23
23 For questions or bug reports please contact: 24 For questions or bug reports please contact:
24 25
25 smfrench@gmail.com 26 smfrench@gmail.com
26 27
27 See the project page at: https://wiki.samba.or 28 See the project page at: https://wiki.samba.org/index.php/LinuxCIFS_utils
28 29
29 Build instructions 30 Build instructions
30 ================== 31 ==================
31 32
32 For Linux: 33 For Linux:
33 34
34 1) Download the kernel (e.g. from https://www. !! 35 1) Download the kernel (e.g. from http://www.kernel.org)
35 and change directory into the top of the ke 36 and change directory into the top of the kernel directory tree
36 (e.g. /usr/src/linux-2.5.73) 37 (e.g. /usr/src/linux-2.5.73)
37 2) make menuconfig (or make xconfig) 38 2) make menuconfig (or make xconfig)
38 3) select cifs from within the network filesys 39 3) select cifs from within the network filesystem choices
39 4) save and exit 40 4) save and exit
40 5) make 41 5) make
41 42
42 43
43 Installation instructions 44 Installation instructions
44 ========================= 45 =========================
45 46
46 If you have built the CIFS vfs as module (succ 47 If you have built the CIFS vfs as module (successfully) simply
47 type ``make modules_install`` (or if you prefe 48 type ``make modules_install`` (or if you prefer, manually copy the file to
48 the modules directory e.g. /lib/modules/6.3.0- !! 49 the modules directory e.g. /lib/modules/2.4.10-4GB/kernel/fs/cifs/cifs.ko).
49 50
50 If you have built the CIFS vfs into the kernel 51 If you have built the CIFS vfs into the kernel itself, follow the instructions
51 for your distribution on how to install a new 52 for your distribution on how to install a new kernel (usually you
52 would simply type ``make install``). 53 would simply type ``make install``).
53 54
54 If you do not have the utility mount.cifs (in 55 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 56 the CIFS VFS web site) copy it to the same directory in which mount helpers
56 reside (usually /sbin). Although the helper s 57 reside (usually /sbin). Although the helper software is not
57 required, mount.cifs is recommended. Most dis 58 required, mount.cifs is recommended. Most distros include a ``cifs-utils``
58 package that includes this utility so it is re 59 package that includes this utility so it is recommended to install this.
59 60
60 Note that running the Winbind pam/nss module ( 61 Note that running the Winbind pam/nss module (logon service) on all of your
61 Linux clients is useful in mapping Uids and Gi 62 Linux clients is useful in mapping Uids and Gids consistently across the
62 domain to the proper network user. The mount. 63 domain to the proper network user. The mount.cifs mount helper can be
63 found at cifs-utils.git on git.samba.org 64 found at cifs-utils.git on git.samba.org
64 65
65 If cifs is built as a module, then the size an 66 If cifs is built as a module, then the size and number of network buffers
66 and maximum number of simultaneous requests to 67 and maximum number of simultaneous requests to one server can be configured.
67 Changing these from their defaults is not reco 68 Changing these from their defaults is not recommended. By executing modinfo::
68 69
69 modinfo <path to cifs.ko> !! 70 modinfo kernel/fs/cifs/cifs.ko
70 71
71 on kernel/fs/smb/client/cifs.ko the list of co !! 72 on kernel/fs/cifs/cifs.ko the list of configuration changes that can be made
72 at module initialization time (by running insm 73 at module initialization time (by running insmod cifs.ko) can be seen.
73 74
74 Recommendations 75 Recommendations
75 =============== 76 ===============
76 77
77 To improve security the SMB2.1 dialect or late !! 78 To improve security the SMB2.1 dialect or later (usually will get SMB3) is now
78 the new default. To use old dialects (e.g. to 79 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 80 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 81 much older and less secure than the default dialect SMB3 which includes
81 many advanced security features such as downgr 82 many advanced security features such as downgrade attack detection
82 and encrypted shares and stronger signing and 83 and encrypted shares and stronger signing and authentication algorithms.
83 There are additional mount options that may be 84 There are additional mount options that may be helpful for SMB3 to get
84 improved POSIX behavior (NB: can use vers=3 to !! 85 improved POSIX behavior (NB: can use vers=3.0 to force only SMB3, never 2.1):
85 86
86 ``mfsymlinks`` and either ``cifsacl`` or `` !! 87 ``mfsymlinks`` and ``cifsacl`` and ``idsfromsid``
87 88
88 Allowing User Mounts 89 Allowing User Mounts
89 ==================== 90 ====================
90 91
91 To permit users to mount and unmount over dire 92 To permit users to mount and unmount over directories they own is possible
92 with the cifs vfs. A way to enable such mount 93 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 94 utility as suid (e.g. ``chmod +s /sbin/mount.cifs``). To enable users to
94 umount shares they mount requires 95 umount shares they mount requires
95 96
96 1) mount.cifs version 1.4 or later 97 1) mount.cifs version 1.4 or later
97 2) an entry for the share in /etc/fstab indica 98 2) an entry for the share in /etc/fstab indicating that a user may
98 unmount it e.g.:: 99 unmount it e.g.::
99 100
100 //server/usersharename /mnt/username cif 101 //server/usersharename /mnt/username cifs user 0 0
101 102
102 Note that when the mount.cifs utility is run s 103 Note that when the mount.cifs utility is run suid (allowing user mounts),
103 in order to reduce risks, the ``nosuid`` mount 104 in order to reduce risks, the ``nosuid`` mount flag is passed in on mount to
104 disallow execution of an suid program mounted 105 disallow execution of an suid program mounted on the remote target.
105 When mount is executed as root, nosuid is not 106 When mount is executed as root, nosuid is not passed in by default,
106 and execution of suid programs on the remote t 107 and execution of suid programs on the remote target would be enabled
107 by default. This can be changed, as with nfs a 108 by default. This can be changed, as with nfs and other filesystems,
108 by simply specifying ``nosuid`` among the moun 109 by simply specifying ``nosuid`` among the mount options. For user mounts
109 though to be able to pass the suid flag to mou 110 though to be able to pass the suid flag to mount requires rebuilding
110 mount.cifs with the following flag: CIFS_ALLOW 111 mount.cifs with the following flag: CIFS_ALLOW_USR_SUID
111 112
112 There is a corresponding manual page for cifs 113 There is a corresponding manual page for cifs mounting in the Samba 3.0 and
113 later source tree in docs/manpages/mount.cifs. 114 later source tree in docs/manpages/mount.cifs.8
114 115
115 Allowing User Unmounts 116 Allowing User Unmounts
116 ====================== 117 ======================
117 118
118 To permit users to unmount directories that th !! 119 To permit users to ummount directories that they have user mounted (see above),
119 the utility umount.cifs may be used. It may b 120 the utility umount.cifs may be used. It may be invoked directly, or if
120 umount.cifs is placed in /sbin, umount can inv 121 umount.cifs is placed in /sbin, umount can invoke the cifs umount helper
121 (at least for most versions of the umount util 122 (at least for most versions of the umount utility) for umount of cifs
122 mounts, unless umount is invoked with -i (whic 123 mounts, unless umount is invoked with -i (which will avoid invoking a umount
123 helper). As with mount.cifs, to enable user un 124 helper). As with mount.cifs, to enable user unmounts umount.cifs must be marked
124 as suid (e.g. ``chmod +s /sbin/umount.cifs``) 125 as suid (e.g. ``chmod +s /sbin/umount.cifs``) or equivalent (some distributions
125 allow adding entries to a file to the /etc/per 126 allow adding entries to a file to the /etc/permissions file to achieve the
126 equivalent suid effect). For this utility to 127 equivalent suid effect). For this utility to succeed the target path
127 must be a cifs mount, and the uid of the curre 128 must be a cifs mount, and the uid of the current user must match the uid
128 of the user who mounted the resource. 129 of the user who mounted the resource.
129 130
130 Also note that the customary way of allowing u 131 Also note that the customary way of allowing user mounts and unmounts is
131 (instead of using mount.cifs and unmount.cifs 132 (instead of using mount.cifs and unmount.cifs as suid) to add a line
132 to the file /etc/fstab for each //server/share 133 to the file /etc/fstab for each //server/share you wish to mount, but
133 this can become unwieldy when potential mount 134 this can become unwieldy when potential mount targets include many
134 or unpredictable UNC names. 135 or unpredictable UNC names.
135 136
136 Samba Considerations 137 Samba Considerations
137 ==================== 138 ====================
138 139
139 Most current servers support SMB2.1 and SMB3 w 140 Most current servers support SMB2.1 and SMB3 which are more secure,
140 but there are useful protocol extensions for t 141 but there are useful protocol extensions for the older less secure CIFS
141 dialect, so to get the maximum benefit if moun 142 dialect, so to get the maximum benefit if mounting using the older dialect
142 (CIFS/SMB1), we recommend using a server that 143 (CIFS/SMB1), we recommend using a server that supports the SNIA CIFS
143 Unix Extensions standard (e.g. almost any ver 144 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 145 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 146 Note that uid, gid and file permissions will display default values if you do
146 not have a server that supports the Unix exten 147 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 148 2.2.5 or later). To enable the Unix CIFS Extensions in the Samba server, add
148 the line:: 149 the line::
149 150
150 unix extensions = yes 151 unix extensions = yes
151 152
152 to your smb.conf file on the server. Note tha 153 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 154 are also useful (on the Samba server) when the majority of clients are Unix or
154 Linux:: 155 Linux::
155 156
156 case sensitive = yes 157 case sensitive = yes
157 delete readonly = yes 158 delete readonly = yes
158 ea support = yes 159 ea support = yes
159 160
160 Note that server ea support is required for su 161 Note that server ea support is required for supporting xattrs from the Linux
161 cifs client, and that EA support is present in 162 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 163 3.0.6 and later (also EA support works in all versions of Windows, at least to
163 shares on NTFS filesystems). Extended Attribu 164 shares on NTFS filesystems). Extended Attribute (xattr) support is an optional
164 feature of most Linux filesystems which may re 165 feature of most Linux filesystems which may require enabling via
165 make menuconfig. Client support for extended a 166 make menuconfig. Client support for extended attributes (user xattr) can be
166 disabled on a per-mount basis by specifying `` 167 disabled on a per-mount basis by specifying ``nouser_xattr`` on mount.
167 168
168 The CIFS client can get and set POSIX ACLs (ge 169 The CIFS client can get and set POSIX ACLs (getfacl, setfacl) to Samba servers
169 version 3.10 and later. Setting POSIX ACLs re 170 version 3.10 and later. Setting POSIX ACLs requires enabling both XATTR and
170 then POSIX support in the CIFS configuration o 171 then POSIX support in the CIFS configuration options when building the cifs
171 module. POSIX ACL support can be disabled on 172 module. POSIX ACL support can be disabled on a per mount basic by specifying
172 ``noacl`` on mount. 173 ``noacl`` on mount.
173 174
174 Some administrators may want to change Samba's 175 Some administrators may want to change Samba's smb.conf ``map archive`` and
175 ``create mask`` parameters from the default. 176 ``create mask`` parameters from the default. Unless the create mask is changed
176 newly created files can end up with an unneces 177 newly created files can end up with an unnecessarily restrictive default mode,
177 which may not be what you want, although if th 178 which may not be what you want, although if the CIFS Unix extensions are
178 enabled on the server and client, subsequent s 179 enabled on the server and client, subsequent setattr calls (e.g. chmod) can
179 fix the mode. Note that creating special devi 180 fix the mode. Note that creating special devices (mknod) remotely
180 may require specifying a mkdev function to Sam 181 may require specifying a mkdev function to Samba if you are not using
181 Samba 3.0.6 or later. For more information on 182 Samba 3.0.6 or later. For more information on these see the manual pages
182 (``man smb.conf``) on the Samba server system. 183 (``man smb.conf``) on the Samba server system. Note that the cifs vfs,
183 unlike the smbfs vfs, does not read the smb.co 184 unlike the smbfs vfs, does not read the smb.conf on the client system
184 (the few optional settings are passed in on mo 185 (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 186 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 187 open files (required for strict POSIX compliance). Windows Servers already
187 supported this feature. Samba server does not 188 supported this feature. Samba server does not allow symlinks that refer to files
188 outside of the share, so in Samba versions pri 189 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 190 files with absolute paths (ie beginning with slash) such as::
190 191
191 ln -s /mnt/foo bar 192 ln -s /mnt/foo bar
192 193
193 would be forbidden. Samba 3.0.6 server or late 194 would be forbidden. Samba 3.0.6 server or later includes the ability to create
194 such symlinks safely by converting unsafe syml 195 such symlinks safely by converting unsafe symlinks (ie symlinks to server
195 files that are outside of the share) to a samb 196 files that are outside of the share) to a samba specific format on the server
196 that is ignored by local server applications a 197 that is ignored by local server applications and non-cifs clients and that will
197 not be traversed by the Samba server). This i 198 not be traversed by the Samba server). This is opaque to the Linux client
198 application using the cifs vfs. Absolute symli 199 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 200 later, but only for remote clients using the CIFS Unix extensions, and will
200 be invisible to Windows clients and typically !! 201 be invisbile to Windows clients and typically will not affect local
201 applications running on the same server as Sam 202 applications running on the same server as Samba.
202 203
203 Use instructions 204 Use instructions
204 ================ 205 ================
205 206
206 Once the CIFS VFS support is built into the ke 207 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 208 (cifs.ko), you can use mount syntax like the following to access Samba or
208 Mac or Windows servers:: 209 Mac or Windows servers::
209 210
210 mount -t cifs //9.53.216.11/e$ /mnt -o usern 211 mount -t cifs //9.53.216.11/e$ /mnt -o username=myname,password=mypassword
211 212
212 Before -o the option -v may be specified to ma 213 Before -o the option -v may be specified to make the mount.cifs
213 mount helper display the mount steps more verb 214 mount helper display the mount steps more verbosely.
214 After -o the following commonly used cifs vfs 215 After -o the following commonly used cifs vfs specific options
215 are supported:: 216 are supported::
216 217
217 username=<username> 218 username=<username>
218 password=<password> 219 password=<password>
219 domain=<domain name> 220 domain=<domain name>
220 221
221 Other cifs mount options are described below. 222 Other cifs mount options are described below. Use of TCP names (in addition to
222 ip addresses) is available if the mount helper 223 ip addresses) is available if the mount helper (mount.cifs) is installed. If
223 you do not trust the server to which are mount 224 you do not trust the server to which are mounted, or if you do not have
224 cifs signing enabled (and the physical network 225 cifs signing enabled (and the physical network is insecure), consider use
225 of the standard mount options ``noexec`` and ` 226 of the standard mount options ``noexec`` and ``nosuid`` to reduce the risk of
226 running an altered binary on your local system 227 running an altered binary on your local system (downloaded from a hostile server
227 or altered by a hostile router). 228 or altered by a hostile router).
228 229
229 Although mounting using format corresponding t 230 Although mounting using format corresponding to the CIFS URL specification is
230 not possible in mount.cifs yet, it is possible 231 not possible in mount.cifs yet, it is possible to use an alternate format
231 for the server and sharename (which is somewha 232 for the server and sharename (which is somewhat similar to NFS style mount
232 syntax) instead of the more widely used UNC fo 233 syntax) instead of the more widely used UNC format (i.e. \\server\share)::
233 234
234 mount -t cifs tcp_name_of_server:share_name 235 mount -t cifs tcp_name_of_server:share_name /mnt -o user=myname,pass=mypasswd
235 236
236 When using the mount helper mount.cifs, passwo 237 When using the mount helper mount.cifs, passwords may be specified via alternate
237 mechanisms, instead of specifying it after -o 238 mechanisms, instead of specifying it after -o using the normal ``pass=`` syntax
238 on the command line: 239 on the command line:
239 1) By including it in a credential file. Speci 240 1) By including it in a credential file. Specify credentials=filename as one
240 of the mount options. Credential files contain 241 of the mount options. Credential files contain two lines::
241 242
242 username=someuser 243 username=someuser
243 password=your_password 244 password=your_password
244 245
245 2) By specifying the password in the PASSWD en 246 2) By specifying the password in the PASSWD environment variable (similarly
246 the user name can be taken from the USER en 247 the user name can be taken from the USER environment variable).
247 3) By specifying the password in a file by nam 248 3) By specifying the password in a file by name via PASSWD_FILE
248 4) By specifying the password in a file by fil 249 4) By specifying the password in a file by file descriptor via PASSWD_FD
249 250
250 If no password is provided, mount.cifs will pr 251 If no password is provided, mount.cifs will prompt for password entry
251 252
252 Restrictions 253 Restrictions
253 ============ 254 ============
254 255
255 Servers must support either "pure-TCP" (port 4 256 Servers must support either "pure-TCP" (port 445 TCP/IP CIFS connections) or RFC
256 1001/1002 support for "Netbios-Over-TCP/IP." T 257 1001/1002 support for "Netbios-Over-TCP/IP." This is not likely to be a
257 problem as most servers support this. 258 problem as most servers support this.
258 259
259 Valid filenames differ between Windows and Lin 260 Valid filenames differ between Windows and Linux. Windows typically restricts
260 filenames which contain certain reserved chara 261 filenames which contain certain reserved characters (e.g.the character :
261 which is used to delimit the beginning of a st 262 which is used to delimit the beginning of a stream name by Windows), while
262 Linux allows a slightly wider set of valid cha 263 Linux allows a slightly wider set of valid characters in filenames. Windows
263 servers can remap such characters when an expl 264 servers can remap such characters when an explicit mapping is specified in
264 the Server's registry. Samba starting with ve 265 the Server's registry. Samba starting with version 3.10 will allow such
265 filenames (ie those which contain valid Linux 266 filenames (ie those which contain valid Linux characters, which normally
266 would be forbidden for Windows/CIFS semantics) 267 would be forbidden for Windows/CIFS semantics) as long as the server is
267 configured for Unix Extensions (and the client 268 configured for Unix Extensions (and the client has not disabled
268 /proc/fs/cifs/LinuxExtensionsEnabled). In addi 269 /proc/fs/cifs/LinuxExtensionsEnabled). In addition the mount option
269 ``mapposix`` can be used on CIFS (vers=1.0) to 270 ``mapposix`` can be used on CIFS (vers=1.0) to force the mapping of
270 illegal Windows/NTFS/SMB characters to a remap !! 271 illegal Windows/NTFS/SMB characters to a remap range (this mount parm
271 is the default for SMB3). This remap (``mappos 272 is the default for SMB3). This remap (``mapposix``) range is also
272 compatible with Mac (and "Services for Mac" on 273 compatible with Mac (and "Services for Mac" on some older Windows).
273 274
274 CIFS VFS Mount Options 275 CIFS VFS Mount Options
275 ====================== 276 ======================
276 A partial list of the supported mount options 277 A partial list of the supported mount options follows:
277 278
278 username 279 username
279 The user name to use when tryi 280 The user name to use when trying to establish
280 the CIFS session. 281 the CIFS session.
281 password 282 password
282 The user password. If the mou 283 The user password. If the mount helper is
283 installed, the user will be pr 284 installed, the user will be prompted for password
284 if not supplied. 285 if not supplied.
285 ip 286 ip
286 The ip address of the target s 287 The ip address of the target server
287 unc 288 unc
288 The target server Universal Ne 289 The target server Universal Network Name (export) to
289 mount. 290 mount.
290 domain 291 domain
291 Set the SMB/CIFS workgroup nam 292 Set the SMB/CIFS workgroup name prepended to the
292 username during CIFS session e 293 username during CIFS session establishment
293 forceuid 294 forceuid
294 Set the default uid for inodes 295 Set the default uid for inodes to the uid
295 passed in on mount. For mounts 296 passed in on mount. For mounts to servers
296 which do support the CIFS Unix 297 which do support the CIFS Unix extensions, such as a
297 properly configured Samba serv 298 properly configured Samba server, the server provides
298 the uid, gid and mode so this 299 the uid, gid and mode so this parameter should not be
299 specified unless the server an 300 specified unless the server and clients uid and gid
300 numbering differ. If the serv 301 numbering differ. If the server and client are in the
301 same domain (e.g. running winb 302 same domain (e.g. running winbind or nss_ldap) and
302 the server supports the Unix E 303 the server supports the Unix Extensions then the uid
303 and gid can be retrieved from 304 and gid can be retrieved from the server (and uid
304 and gid would not have to be s 305 and gid would not have to be specified on the mount.
305 For servers which do not suppo 306 For servers which do not support the CIFS Unix
306 extensions, the default uid (a 307 extensions, the default uid (and gid) returned on lookup
307 of existing files will be the 308 of existing files will be the uid (gid) of the person
308 who executed the mount (root, 309 who executed the mount (root, except when mount.cifs
309 is configured setuid for user 310 is configured setuid for user mounts) unless the ``uid=``
310 (gid) mount option is specifie 311 (gid) mount option is specified. Also note that permission
311 checks (authorization checks) 312 checks (authorization checks) on accesses to a file occur
312 at the server, but there are c 313 at the server, but there are cases in which an administrator
313 may want to restrict at the cl 314 may want to restrict at the client as well. For those
314 servers which do not report a 315 servers which do not report a uid/gid owner
315 (such as Windows), permissions 316 (such as Windows), permissions can also be checked at the
316 client, and a crude form of cl 317 client, and a crude form of client side permission checking
317 can be enabled by specifying f 318 can be enabled by specifying file_mode and dir_mode on
318 the client. (default) 319 the client. (default)
319 forcegid 320 forcegid
320 (similar to above but for the 321 (similar to above but for the groupid instead of uid) (default)
321 noforceuid 322 noforceuid
322 Fill in file owner information 323 Fill in file owner information (uid) by requesting it from
323 the server if possible. With t 324 the server if possible. With this option, the value given in
324 the uid= option (on mount) wil 325 the uid= option (on mount) will only be used if the server
325 can not support returning uids 326 can not support returning uids on inodes.
326 noforcegid 327 noforcegid
327 (similar to above but for the 328 (similar to above but for the group owner, gid, instead of uid)
328 uid 329 uid
329 Set the default uid for inodes 330 Set the default uid for inodes, and indicate to the
330 cifs kernel driver which local 331 cifs kernel driver which local user mounted. If the server
331 supports the unix extensions t 332 supports the unix extensions the default uid is
332 not used to fill in the owner 333 not used to fill in the owner fields of inodes (files)
333 unless the ``forceuid`` parame 334 unless the ``forceuid`` parameter is specified.
334 gid 335 gid
335 Set the default gid for inodes 336 Set the default gid for inodes (similar to above).
336 file_mode 337 file_mode
337 If CIFS Unix extensions are no 338 If CIFS Unix extensions are not supported by the server
338 this overrides the default mod 339 this overrides the default mode for file inodes.
339 fsc 340 fsc
340 Enable local disk caching usin 341 Enable local disk caching using FS-Cache (off by default). This
341 option could be useful to impr 342 option could be useful to improve performance on a slow link,
342 heavily loaded server and/or n 343 heavily loaded server and/or network where reading from the
343 disk is faster than reading fr 344 disk is faster than reading from the server (over the network).
344 This could also impact scalabi 345 This could also impact scalability positively as the
345 number of calls to the server 346 number of calls to the server are reduced. However, local
346 caching is not suitable for al 347 caching is not suitable for all workloads for e.g. read-once
347 type workloads. So, you need t 348 type workloads. So, you need to consider carefully your
348 workload/scenario before using 349 workload/scenario before using this option. Currently, local
349 disk caching is functional for 350 disk caching is functional for CIFS files opened as read-only.
350 dir_mode 351 dir_mode
351 If CIFS Unix extensions are no 352 If CIFS Unix extensions are not supported by the server
352 this overrides the default mod 353 this overrides the default mode for directory inodes.
353 port 354 port
354 attempt to contact the server 355 attempt to contact the server on this tcp port, before
355 trying the usual ports (port 4 356 trying the usual ports (port 445, then 139).
356 iocharset 357 iocharset
357 Codepage used to convert local 358 Codepage used to convert local path names to and from
358 Unicode. Unicode is used by de 359 Unicode. Unicode is used by default for network path
359 names if the server supports i 360 names if the server supports it. If iocharset is
360 not specified then the nls_def 361 not specified then the nls_default specified
361 during the local client kernel 362 during the local client kernel build will be used.
362 If server does not support Uni 363 If server does not support Unicode, this parameter is
363 unused. 364 unused.
364 rsize 365 rsize
365 default read size (usually 16K 366 default read size (usually 16K). The client currently
366 can not use rsize larger than 367 can not use rsize larger than CIFSMaxBufSize. CIFSMaxBufSize
367 defaults to 16K and may be cha 368 defaults to 16K and may be changed (from 8K to the maximum
368 kmalloc size allowed by your k 369 kmalloc size allowed by your kernel) at module install time
369 for cifs.ko. Setting CIFSMaxBu 370 for cifs.ko. Setting CIFSMaxBufSize to a very large value
370 will cause cifs to use more me 371 will cause cifs to use more memory and may reduce performance
371 in some cases. To use rsize g 372 in some cases. To use rsize greater than 127K (the original
372 cifs protocol maximum) also re 373 cifs protocol maximum) also requires that the server support
373 a new Unix Capability flag (fo 374 a new Unix Capability flag (for very large read) which some
374 newer servers (e.g. Samba 3.0. 375 newer servers (e.g. Samba 3.0.26 or later) do. rsize can be
375 set from a minimum of 2048 to 376 set from a minimum of 2048 to a maximum of 130048 (127K or
376 CIFSMaxBufSize, whichever is s 377 CIFSMaxBufSize, whichever is smaller)
377 wsize 378 wsize
378 default write size (default 57 379 default write size (default 57344)
379 maximum wsize currently allowe 380 maximum wsize currently allowed by CIFS is 57344 (fourteen
380 4096 byte pages) 381 4096 byte pages)
381 actimeo=n 382 actimeo=n
382 attribute cache timeout in sec 383 attribute cache timeout in seconds (default 1 second).
383 After this timeout, the cifs c 384 After this timeout, the cifs client requests fresh attribute
384 information from the server. T 385 information from the server. This option allows to tune the
385 attribute cache timeout to sui 386 attribute cache timeout to suit the workload needs. Shorter
386 timeouts mean better the cache 387 timeouts mean better the cache coherency, but increased number
387 of calls to the server. Longer 388 of calls to the server. Longer timeouts mean reduced number
388 of calls to the server at the 389 of calls to the server at the expense of less stricter cache
389 coherency checks (i.e. incorre 390 coherency checks (i.e. incorrect attribute cache for a short
390 period of time). 391 period of time).
391 rw 392 rw
392 mount the network share read-w 393 mount the network share read-write (note that the
393 server may still consider the 394 server may still consider the share read-only)
394 ro 395 ro
395 mount network share read-only 396 mount network share read-only
396 version 397 version
397 used to distinguish different 398 used to distinguish different versions of the
398 mount helper utility (not typi 399 mount helper utility (not typically needed)
399 sep 400 sep
400 if first mount option (after t 401 if first mount option (after the -o), overrides
401 the comma as the separator bet 402 the comma as the separator between the mount
402 parameters. e.g.:: !! 403 parms. e.g.::
403 404
404 -o user=myname,passwor 405 -o user=myname,password=mypassword,domain=mydom
405 406
406 could be passed instead with p 407 could be passed instead with period as the separator by::
407 408
408 -o sep=.user=myname.pa 409 -o sep=.user=myname.password=mypassword.domain=mydom
409 410
410 this might be useful when comm 411 this might be useful when comma is contained within username
411 or password or domain. This op 412 or password or domain. This option is less important
412 when the cifs mount helper cif 413 when the cifs mount helper cifs.mount (version 1.1 or later)
413 is used. 414 is used.
414 nosuid 415 nosuid
415 Do not allow remote executable 416 Do not allow remote executables with the suid bit
416 program to be executed. This 417 program to be executed. This is only meaningful for mounts
417 to servers such as Samba which 418 to servers such as Samba which support the CIFS Unix Extensions.
418 If you do not trust the server 419 If you do not trust the servers in your network (your mount
419 targets) it is recommended tha 420 targets) it is recommended that you specify this option for
420 greater security. 421 greater security.
421 exec 422 exec
422 Permit execution of binaries o 423 Permit execution of binaries on the mount.
423 noexec 424 noexec
424 Do not permit execution of bin 425 Do not permit execution of binaries on the mount.
425 dev 426 dev
426 Recognize block devices on the 427 Recognize block devices on the remote mount.
427 nodev 428 nodev
428 Do not recognize devices on th 429 Do not recognize devices on the remote mount.
429 suid 430 suid
430 Allow remote files on this mou 431 Allow remote files on this mountpoint with suid enabled to
431 be executed (default for mount 432 be executed (default for mounts when executed as root,
432 nosuid is default for user mou 433 nosuid is default for user mounts).
433 credentials 434 credentials
434 Although ignored by the cifs k 435 Although ignored by the cifs kernel component, it is used by
435 the mount helper, mount.cifs. 436 the mount helper, mount.cifs. When mount.cifs is installed it
436 opens and reads the credential 437 opens and reads the credential file specified in order
437 to obtain the userid and passw 438 to obtain the userid and password arguments which are passed to
438 the cifs vfs. 439 the cifs vfs.
439 guest 440 guest
440 Although ignored by the kernel 441 Although ignored by the kernel component, the mount.cifs
441 mount helper will not prompt t 442 mount helper will not prompt the user for a password
442 if guest is specified on the m 443 if guest is specified on the mount options. If no
443 password is specified a null p 444 password is specified a null password will be used.
444 perm 445 perm
445 Client does permission checks 446 Client does permission checks (vfs_permission check of uid
446 and gid of the file against th 447 and gid of the file against the mode and desired operation),
447 Note that this is in addition 448 Note that this is in addition to the normal ACL check on the
448 target machine done by the ser 449 target machine done by the server software.
449 Client permission checking is 450 Client permission checking is enabled by default.
450 noperm 451 noperm
451 Client does not do permission 452 Client does not do permission checks. This can expose
452 files on this mount to access 453 files on this mount to access by other users on the local
453 client system. It is typically 454 client system. It is typically only needed when the server
454 supports the CIFS Unix Extensi 455 supports the CIFS Unix Extensions but the UIDs/GIDs on the
455 client and server system do no 456 client and server system do not match closely enough to allow
456 access by the user doing the m 457 access by the user doing the mount, but it may be useful with
457 non CIFS Unix Extension mounts 458 non CIFS Unix Extension mounts for cases in which the default
458 mode is specified on the mount 459 mode is specified on the mount but is not to be enforced on the
459 client (e.g. perhaps when Mult 460 client (e.g. perhaps when MultiUserMount is enabled)
460 Note that this does not affect 461 Note that this does not affect the normal ACL check on the
461 target machine done by the ser 462 target machine done by the server software (of the server
462 ACL against the user name prov 463 ACL against the user name provided at mount time).
463 serverino 464 serverino
464 Use server's inode numbers ins 465 Use server's inode numbers instead of generating automatically
465 incrementing inode numbers on 466 incrementing inode numbers on the client. Although this will
466 make it easier to spot hardlin 467 make it easier to spot hardlinked files (as they will have
467 the same inode numbers) and in 468 the same inode numbers) and inode numbers may be persistent,
468 note that the server does not 469 note that the server does not guarantee that the inode numbers
469 are unique if multiple server 470 are unique if multiple server side mounts are exported under a
470 single share (since inode numb 471 single share (since inode numbers on the servers might not
471 be unique if multiple filesyst 472 be unique if multiple filesystems are mounted under the same
472 shared higher level directory) 473 shared higher level directory). Note that some older
473 (e.g. pre-Windows 2000) do not 474 (e.g. pre-Windows 2000) do not support returning UniqueIDs
474 or the CIFS Unix Extensions eq 475 or the CIFS Unix Extensions equivalent and for those
475 this mount option will have no 476 this mount option will have no effect. Exporting cifs mounts
476 under nfsd requires this mount 477 under nfsd requires this mount option on the cifs mount.
477 This is now the default if ser 478 This is now the default if server supports the
478 required network operation. 479 required network operation.
479 noserverino 480 noserverino
480 Client generates inode numbers 481 Client generates inode numbers (rather than using the actual one
481 from the server). These inode 482 from the server). These inode numbers will vary after
482 unmount or reboot which can co 483 unmount or reboot which can confuse some applications,
483 but not all server filesystems 484 but not all server filesystems support unique inode
484 numbers. 485 numbers.
485 setuids 486 setuids
486 If the CIFS Unix extensions ar 487 If the CIFS Unix extensions are negotiated with the server
487 the client will attempt to set 488 the client will attempt to set the effective uid and gid of
488 the local process on newly cre 489 the local process on newly created files, directories, and
489 devices (create, mkdir, mknod) 490 devices (create, mkdir, mknod). If the CIFS Unix Extensions
490 are not negotiated, for newly 491 are not negotiated, for newly created files and directories
491 instead of using the default u 492 instead of using the default uid and gid specified on
492 the mount, cache the new file' 493 the mount, cache the new file's uid and gid locally which means
493 that the uid for the file can 494 that the uid for the file can change when the inode is
494 reloaded (or the user remounts 495 reloaded (or the user remounts the share).
495 nosetuids 496 nosetuids
496 The client will not attempt to 497 The client will not attempt to set the uid and gid on
497 on newly created files, direct 498 on newly created files, directories, and devices (create,
498 mkdir, mknod) which will resul 499 mkdir, mknod) which will result in the server setting the
499 uid and gid to the default (us 500 uid and gid to the default (usually the server uid of the
500 user who mounted the share). 501 user who mounted the share). Letting the server (rather than
501 the client) set the uid and gi 502 the client) set the uid and gid is the default. If the CIFS
502 Unix Extensions are not negoti 503 Unix Extensions are not negotiated then the uid and gid for
503 new files will appear to be th 504 new files will appear to be the uid (gid) of the mounter or the
504 uid (gid) parameter specified 505 uid (gid) parameter specified on the mount.
505 netbiosname 506 netbiosname
506 When mounting to servers via p 507 When mounting to servers via port 139, specifies the RFC1001
507 source name to use to represen 508 source name to use to represent the client netbios machine
508 name when doing the RFC1001 ne 509 name when doing the RFC1001 netbios session initialize.
509 direct 510 direct
510 Do not do inode data caching o 511 Do not do inode data caching on files opened on this mount.
511 This precludes mmapping files 512 This precludes mmapping files on this mount. In some cases
512 with fast networks and little 513 with fast networks and little or no caching benefits on the
513 client (e.g. when the applicat 514 client (e.g. when the application is doing large sequential
514 reads bigger than page size wi 515 reads bigger than page size without rereading the same data)
515 this can provide better perfor 516 this can provide better performance than the default
516 behavior which caches reads (r 517 behavior which caches reads (readahead) and writes
517 (writebehind) through the loca 518 (writebehind) through the local Linux client pagecache
518 if oplock (caching token) is g 519 if oplock (caching token) is granted and held. Note that
519 direct allows write operations 520 direct allows write operations larger than page size
520 to be sent to the server. 521 to be sent to the server.
521 strictcache 522 strictcache
522 Use for switching on strict ca 523 Use for switching on strict cache mode. In this mode the
523 client read from the cache all 524 client read from the cache all the time it has Oplock Level II,
524 otherwise - read from the serv 525 otherwise - read from the server. All written data are stored
525 in the cache, but if the clien 526 in the cache, but if the client doesn't have Exclusive Oplock,
526 it writes the data to the serv 527 it writes the data to the server.
527 rwpidforward 528 rwpidforward
528 Forward pid of a process who o 529 Forward pid of a process who opened a file to any read or write
529 operation on that file. This p 530 operation on that file. This prevent applications like WINE
530 from failing on read and write 531 from failing on read and write if we use mandatory brlock style.
531 acl 532 acl
532 Allow setfacl and getfacl to m 533 Allow setfacl and getfacl to manage posix ACLs if server
533 supports them. (default) 534 supports them. (default)
534 noacl 535 noacl
535 Do not allow setfacl and getfa 536 Do not allow setfacl and getfacl calls on this mount
536 user_xattr 537 user_xattr
537 Allow getting and setting user 538 Allow getting and setting user xattrs (those attributes whose
538 name begins with ``user.`` or 539 name begins with ``user.`` or ``os2.``) as OS/2 EAs (extended
539 attributes) to the server. Th 540 attributes) to the server. This allows support of the
540 setfattr and getfattr utilitie 541 setfattr and getfattr utilities. (default)
541 nouser_xattr 542 nouser_xattr
542 Do not allow getfattr/setfattr 543 Do not allow getfattr/setfattr to get/set/list xattrs
543 mapchars 544 mapchars
544 Translate six of the seven res 545 Translate six of the seven reserved characters (not backslash)::
545 546
546 *?<>|: 547 *?<>|:
547 548
548 to the remap range (above 0xF0 549 to the remap range (above 0xF000), which also
549 allows the CIFS client to reco 550 allows the CIFS client to recognize files created with
550 such characters by Windows's P 551 such characters by Windows's POSIX emulation. This can
551 also be useful when mounting t 552 also be useful when mounting to most versions of Samba
552 (which also forbids creating a 553 (which also forbids creating and opening files
553 whose names contain any of the 554 whose names contain any of these seven characters).
554 This has no effect if the serv 555 This has no effect if the server does not support
555 Unicode on the wire. 556 Unicode on the wire.
556 nomapchars 557 nomapchars
557 Do not translate any of these 558 Do not translate any of these seven characters (default).
558 nocase 559 nocase
559 Request case insensitive path 560 Request case insensitive path name matching (case
560 sensitive is the default if th 561 sensitive is the default if the server supports it).
561 (mount option ``ignorecase`` i 562 (mount option ``ignorecase`` is identical to ``nocase``)
562 posixpaths 563 posixpaths
563 If CIFS Unix extensions are su 564 If CIFS Unix extensions are supported, attempt to
564 negotiate posix path name supp 565 negotiate posix path name support which allows certain
565 characters forbidden in typica 566 characters forbidden in typical CIFS filenames, without
566 requiring remapping. (default) 567 requiring remapping. (default)
567 noposixpaths 568 noposixpaths
568 If CIFS Unix extensions are su 569 If CIFS Unix extensions are supported, do not request
569 posix path name support (this 570 posix path name support (this may cause servers to
570 reject creatingfile with certa 571 reject creatingfile with certain reserved characters).
571 nounix 572 nounix
572 Disable the CIFS Unix Extensio 573 Disable the CIFS Unix Extensions for this mount (tree
573 connection). This is rarely ne 574 connection). This is rarely needed, but it may be useful
574 in order to turn off multiple 575 in order to turn off multiple settings all at once (ie
575 posix acls, posix locks, posix 576 posix acls, posix locks, posix paths, symlink support
576 and retrieving uids/gids/mode 577 and retrieving uids/gids/mode from the server) or to
577 work around a bug in server wh 578 work around a bug in server which implement the Unix
578 Extensions. 579 Extensions.
579 nobrl 580 nobrl
580 Do not send byte range lock re 581 Do not send byte range lock requests to the server.
581 This is necessary for certain 582 This is necessary for certain applications that break
582 with cifs style mandatory byte 583 with cifs style mandatory byte range locks (and most
583 cifs servers do not yet suppor 584 cifs servers do not yet support requesting advisory
584 byte range locks). 585 byte range locks).
585 forcemandatorylock 586 forcemandatorylock
586 Even if the server supports po 587 Even if the server supports posix (advisory) byte range
587 locking, send only mandatory l 588 locking, send only mandatory lock requests. For some
588 (presumably rare) applications 589 (presumably rare) applications, originally coded for
589 DOS/Windows, which require Win 590 DOS/Windows, which require Windows style mandatory byte range
590 locking, they may be able to t 591 locking, they may be able to take advantage of this option,
591 forcing the cifs client to onl 592 forcing the cifs client to only send mandatory locks
592 even if the cifs server would 593 even if the cifs server would support posix advisory locks.
593 ``forcemand`` is accepted as a 594 ``forcemand`` is accepted as a shorter form of this mount
594 option. 595 option.
595 nostrictsync 596 nostrictsync
596 If this mount option is set, w 597 If this mount option is set, when an application does an
597 fsync call then the cifs clien 598 fsync call then the cifs client does not send an SMB Flush
598 to the server (to force the se 599 to the server (to force the server to write all dirty data
599 for this file immediately to d 600 for this file immediately to disk), although cifs still sends
600 all dirty (cached) file data t 601 all dirty (cached) file data to the server and waits for the
601 server to respond to the write 602 server to respond to the write. Since SMB Flush can be
602 very slow, and some servers ma 603 very slow, and some servers may be reliable enough (to risk
603 delaying slightly flushing the 604 delaying slightly flushing the data to disk on the server),
604 turning on this option may be 605 turning on this option may be useful to improve performance for
605 applications that fsync too mu 606 applications that fsync too much, at a small risk of server
606 crash. If this mount option i 607 crash. If this mount option is not set, by default cifs will
607 send an SMB flush request (and 608 send an SMB flush request (and wait for a response) on every
608 fsync call. 609 fsync call.
609 nodfs 610 nodfs
610 Disable DFS (global name space 611 Disable DFS (global name space support) even if the
611 server claims to support it. 612 server claims to support it. This can help work around
612 a problem with parsing of DFS 613 a problem with parsing of DFS paths with Samba server
613 versions 3.0.24 and 3.0.25. 614 versions 3.0.24 and 3.0.25.
614 remount 615 remount
615 remount the share (often used 616 remount the share (often used to change from ro to rw mounts
616 or vice versa) 617 or vice versa)
617 cifsacl 618 cifsacl
618 Report mode bits (e.g. on stat 619 Report mode bits (e.g. on stat) based on the Windows ACL for
619 the file. (EXPERIMENTAL) 620 the file. (EXPERIMENTAL)
620 servern 621 servern
621 Specify the server 's netbios 622 Specify the server 's netbios name (RFC1001 name) to use
622 when attempting to setup a ses 623 when attempting to setup a session to the server.
623 This is needed for mounting to 624 This is needed for mounting to some older servers (such
624 as OS/2 or Windows 98 and Wind 625 as OS/2 or Windows 98 and Windows ME) since they do not
625 support a default server name. 626 support a default server name. A server name can be up
626 to 15 characters long and is u 627 to 15 characters long and is usually uppercased.
627 sfu 628 sfu
628 When the CIFS Unix Extensions 629 When the CIFS Unix Extensions are not negotiated, attempt to
629 create device files and fifos 630 create device files and fifos in a format compatible with
630 Services for Unix (SFU). In a 631 Services for Unix (SFU). In addition retrieve bits 10-12
631 of the mode via the SETFILEBIT 632 of the mode via the SETFILEBITS extended attribute (as
632 SFU does). In the future the 633 SFU does). In the future the bottom 9 bits of the
633 mode also will be emulated usi 634 mode also will be emulated using queries of the security
634 descriptor (ACL). 635 descriptor (ACL).
635 mfsymlinks 636 mfsymlinks
636 Enable support for Minshall+Fr 637 Enable support for Minshall+French symlinks
637 (see http://wiki.samba.org/ind 638 (see http://wiki.samba.org/index.php/UNIX_Extensions#Minshall.2BFrench_symlinks)
638 This option is ignored when sp 639 This option is ignored when specified together with the
639 'sfu' option. Minshall+French 640 'sfu' option. Minshall+French symlinks are used even if
640 the server supports the CIFS U 641 the server supports the CIFS Unix Extensions.
641 sign 642 sign
642 Must use packet signing (helps 643 Must use packet signing (helps avoid unwanted data modification
643 by intermediate systems in the 644 by intermediate systems in the route). Note that signing
644 does not work with lanman or p 645 does not work with lanman or plaintext authentication.
645 seal 646 seal
646 Must seal (encrypt) all data o 647 Must seal (encrypt) all data on this mounted share before
647 sending on the network. Requi 648 sending on the network. Requires support for Unix Extensions.
648 Note that this differs from th 649 Note that this differs from the sign mount option in that it
649 causes encryption of data sent 650 causes encryption of data sent over this mounted share but other
650 shares mounted to the same ser 651 shares mounted to the same server are unaffected.
651 locallease 652 locallease
652 This option is rarely needed. 653 This option is rarely needed. Fcntl F_SETLEASE is
653 used by some applications such 654 used by some applications such as Samba and NFSv4 server to
654 check to see whether a file is 655 check to see whether a file is cacheable. CIFS has no way
655 to explicitly request a lease, 656 to explicitly request a lease, but can check whether a file
656 is cacheable (oplocked). Unfo 657 is cacheable (oplocked). Unfortunately, even if a file
657 is not oplocked, it could stil 658 is not oplocked, it could still be cacheable (ie cifs client
658 could grant fcntl leases if no 659 could grant fcntl leases if no other local processes are using
659 the file) for cases for exampl 660 the file) for cases for example such as when the server does not
660 support oplocks and the user i 661 support oplocks and the user is sure that the only updates to
661 the file will be from this cli 662 the file will be from this client. Specifying this mount option
662 will allow the cifs client to 663 will allow the cifs client to check for leases (only) locally
663 for files which are not oplock 664 for files which are not oplocked instead of denying leases
664 in that case. (EXPERIMENTAL) 665 in that case. (EXPERIMENTAL)
665 sec 666 sec
666 Security mode. Allowed values 667 Security mode. Allowed values are:
667 668
668 none 669 none
669 attempt to con 670 attempt to connection as a null user (no name)
670 krb5 671 krb5
671 Use Kerberos v 672 Use Kerberos version 5 authentication
672 krb5i 673 krb5i
673 Use Kerberos a 674 Use Kerberos authentication and packet signing
674 ntlm 675 ntlm
675 Use NTLM passw 676 Use NTLM password hashing (default)
676 ntlmi 677 ntlmi
677 Use NTLM passw 678 Use NTLM password hashing with signing (if
678 /proc/fs/cifs/ 679 /proc/fs/cifs/PacketSigningEnabled on or if
679 server require 680 server requires signing also can be the default)
680 ntlmv2 681 ntlmv2
681 Use NTLMv2 pas 682 Use NTLMv2 password hashing
682 ntlmv2i 683 ntlmv2i
683 Use NTLMv2 pas 684 Use NTLMv2 password hashing with packet signing
684 lanman 685 lanman
685 (if configured 686 (if configured in kernel config) use older
686 lanman hash 687 lanman hash
687 hard 688 hard
688 Retry file operations if serve 689 Retry file operations if server is not responding
689 soft 690 soft
690 Limit retries to unresponsive 691 Limit retries to unresponsive servers (usually only
691 one retry) before returning an 692 one retry) before returning an error. (default)
692 693
693 The mount.cifs mount helper also accepts a few 694 The mount.cifs mount helper also accepts a few mount options before -o
694 including: 695 including:
695 696
696 =============== ============================== 697 =============== ===============================================================
697 -S take password from stdin (equi 698 -S take password from stdin (equivalent to setting the environment
698 variable ``PASSWD_FD=0`` 699 variable ``PASSWD_FD=0``
699 -V print mount.cifs version 700 -V print mount.cifs version
700 -? display simple usage informati 701 -? display simple usage information
701 =============== ============================== 702 =============== ===============================================================
702 703
703 With most 2.6 kernel versions of modutils, the 704 With most 2.6 kernel versions of modutils, the version of the cifs kernel
704 module can be displayed via modinfo. 705 module can be displayed via modinfo.
705 706
706 Misc /proc/fs/cifs Flags and Debug Info 707 Misc /proc/fs/cifs Flags and Debug Info
707 ======================================= 708 =======================================
708 709
709 Informational pseudo-files: 710 Informational pseudo-files:
710 711
711 ======================= ====================== 712 ======================= =======================================================
712 DebugData Displays information a 713 DebugData Displays information about active CIFS sessions and
713 shares, features enabl 714 shares, features enabled as well as the cifs.ko
714 version. 715 version.
715 Stats Lists summary resource 716 Stats Lists summary resource usage information as well as per
716 share statistics. 717 share statistics.
717 open_files List all the open file <<
718 mount_params List of all mount para <<
719 ======================= ====================== 718 ======================= =======================================================
720 719
721 Configuration pseudo-files: 720 Configuration pseudo-files:
722 721
723 ======================= ====================== 722 ======================= =======================================================
724 SecurityFlags Flags which control se 723 SecurityFlags Flags which control security negotiation and
725 also packet signing. A 724 also packet signing. Authentication (may/must)
726 flags (e.g. for NTLMv2 !! 725 flags (e.g. for NTLM and/or NTLMv2) may be combined with
727 the signing flags. Sp 726 the signing flags. Specifying two different password
728 hashing mechanisms (as 727 hashing mechanisms (as "must use") on the other hand
729 does not make much sen 728 does not make much sense. Default flags are::
730 729
731 0x00C5 !! 730 0x07007
732 731
733 (NTLMv2 and packet sig !! 732 (NTLM, NTLMv2 and packet signing allowed). The maximum
734 may require enabling a !! 733 allowable flags if you want to allow mounts to servers
>> 734 using weaker password hashes is 0x37037 (lanman,
>> 735 plaintext, ntlm, ntlmv2, signing allowed). Some
>> 736 SecurityFlags require the corresponding menuconfig
>> 737 options to be enabled (lanman and plaintext require
>> 738 CONFIG_CIFS_WEAK_PW_HASH for example). Enabling
>> 739 plaintext authentication currently requires also
>> 740 enabling lanman authentication in the security flags
>> 741 because the cifs module only supports sending
>> 742 laintext passwords using the older lanman dialect
>> 743 form of the session setup SMB. (e.g. for authentication
>> 744 using plain text passwords, set the SecurityFlags
>> 745 to 0x30030)::
735 746
736 may use packet signi 747 may use packet signing 0x00001
737 must use packet sign 748 must use packet signing 0x01001
>> 749 may use NTLM (most common password hash) 0x00002
>> 750 must use NTLM 0x02002
738 may use NTLMv2 751 may use NTLMv2 0x00004
739 must use NTLMv2 752 must use NTLMv2 0x04004
740 may use Kerberos sec !! 753 may use Kerberos security 0x00008
741 must use Kerberos !! 754 must use Kerberos 0x08008
742 may use NTLMSSP !! 755 may use lanman (weak) password hash 0x00010
743 must use NTLMSSP !! 756 must use lanman password hash 0x10010
744 seal (packet encrypt !! 757 may use plaintext passwords 0x00020
745 must seal !! 758 must use plaintext passwords 0x20020
>> 759 (reserved for future packet encryption) 0x00040
746 760
747 cifsFYI If set to non-zero val 761 cifsFYI If set to non-zero value, additional debug information
748 will be logged to the 762 will be logged to the system error log. This field
749 contains three flags c 763 contains three flags controlling different classes of
750 debugging entries. Th 764 debugging entries. The maximum value it can be set
751 to is 7 which enables 765 to is 7 which enables all debugging points (default 0).
752 Some debugging stateme 766 Some debugging statements are not compiled into the
753 cifs kernel unless CON 767 cifs kernel unless CONFIG_CIFS_DEBUG2 is enabled in the
754 kernel configuration. 768 kernel configuration. cifsFYI may be set to one or
755 more of the following !! 769 nore of the following flags (7 sets them all)::
756 770
757 +------------------- 771 +-----------------------------------------------+------+
758 | log cifs informati 772 | log cifs informational messages | 0x01 |
759 +------------------- 773 +-----------------------------------------------+------+
760 | log return codes f 774 | log return codes from cifs entry points | 0x02 |
761 +------------------- 775 +-----------------------------------------------+------+
762 | log slow responses 776 | log slow responses | 0x04 |
763 | (ie which take lon 777 | (ie which take longer than 1 second) | |
764 | 778 | | |
765 | CONFIG_CIFS_STATS2 779 | CONFIG_CIFS_STATS2 must be enabled in .config | |
766 +------------------- 780 +-----------------------------------------------+------+
767 781
768 traceSMB If set to one, debug i 782 traceSMB If set to one, debug information is logged to the
769 system error log with 783 system error log with the start of smb requests
770 and responses (default 784 and responses (default 0)
771 LookupCacheEnable If set to one, inode i 785 LookupCacheEnable If set to one, inode information is kept cached
772 for one second improvi 786 for one second improving performance of lookups
773 (default 1) 787 (default 1)
774 LinuxExtensionsEnabled If set to one then the 788 LinuxExtensionsEnabled If set to one then the client will attempt to
775 use the CIFS "UNIX" ex 789 use the CIFS "UNIX" extensions which are optional
776 protocol enhancements 790 protocol enhancements that allow CIFS servers
777 to return accurate UID 791 to return accurate UID/GID information as well
778 as support symbolic li 792 as support symbolic links. If you use servers
779 such as Samba that sup 793 such as Samba that support the CIFS Unix
780 extensions but do not 794 extensions but do not want to use symbolic link
781 support and want to ma 795 support and want to map the uid and gid fields
782 to values supplied at 796 to values supplied at mount (rather than the
783 actual values, then se 797 actual values, then set this to zero. (default 1)
784 dfscache List the content of th <<
785 If set to 0, the clien <<
786 ======================= ====================== 798 ======================= =======================================================
787 799
788 These experimental features and tracing can be 800 These experimental features and tracing can be enabled by changing flags in
789 /proc/fs/cifs (after the cifs module has been 801 /proc/fs/cifs (after the cifs module has been installed or built into the
790 kernel, e.g. insmod cifs). To enable a featu 802 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:: 803 tracing to the kernel message log type::
792 804
793 echo 7 > /proc/fs/cifs/cifsFYI 805 echo 7 > /proc/fs/cifs/cifsFYI
794 806
795 cifsFYI functions as a bit mask. Setting it to 807 cifsFYI functions as a bit mask. Setting it to 1 enables additional kernel
796 logging of various informational messages. 2 808 logging of various informational messages. 2 enables logging of non-zero
797 SMB return codes while 4 enables logging of re 809 SMB return codes while 4 enables logging of requests that take longer
798 than one second to complete (except for byte r 810 than one second to complete (except for byte range lock requests).
799 Setting it to 4 requires CONFIG_CIFS_STATS2 to 811 Setting it to 4 requires CONFIG_CIFS_STATS2 to be set in kernel configuration
800 (.config). Setting it to seven enables all thr 812 (.config). Setting it to seven enables all three. Finally, tracing
801 the start of smb requests and responses can be 813 the start of smb requests and responses can be enabled via::
802 814
803 echo 1 > /proc/fs/cifs/traceSMB 815 echo 1 > /proc/fs/cifs/traceSMB
804 816
805 Per share (per client mount) statistics are av 817 Per share (per client mount) statistics are available in /proc/fs/cifs/Stats.
806 Additional information is available if CONFIG_ 818 Additional information is available if CONFIG_CIFS_STATS2 is enabled in the
807 kernel configuration (.config). The statistic 819 kernel configuration (.config). The statistics returned include counters which
808 represent the number of attempted and failed ( 820 represent the number of attempted and failed (ie non-zero return code from the
809 server) SMB3 (or cifs) requests grouped by req 821 server) SMB3 (or cifs) requests grouped by request type (read, write, close etc.).
810 Also recorded is the total bytes read and byte 822 Also recorded is the total bytes read and bytes written to the server for
811 that share. Note that due to client caching e 823 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 824 number of bytes read and written by the application running on the client.
813 Statistics can be reset to zero by ``echo 0 > 825 Statistics can be reset to zero by ``echo 0 > /proc/fs/cifs/Stats`` which may be
814 useful if comparing performance of two differe 826 useful if comparing performance of two different scenarios.
815 827
816 Also note that ``cat /proc/fs/cifs/DebugData`` 828 Also note that ``cat /proc/fs/cifs/DebugData`` will display information about
817 the active sessions and the shares that are mo 829 the active sessions and the shares that are mounted.
818 830
819 Enabling Kerberos (extended security) works bu 831 Enabling Kerberos (extended security) works but requires version 1.2 or later
820 of the helper program cifs.upcall to be presen 832 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 833 /etc/request-key.conf file. The cifs.upcall helper program is from the Samba
822 project(https://www.samba.org). NTLM and NTLMv !! 834 project(http://www.samba.org). NTLM and NTLMv2 and LANMAN support do not
823 require this helper. Note that NTLMv2 security 835 require this helper. Note that NTLMv2 security (which does not require the
824 cifs.upcall helper program), instead of using 836 cifs.upcall helper program), instead of using Kerberos, is sufficient for
825 some use cases. 837 some use cases.
826 838
827 DFS support allows transparent redirection to 839 DFS support allows transparent redirection to shares in an MS-DFS name space.
828 In addition, DFS support for target shares whi 840 In addition, DFS support for target shares which are specified as UNC
829 names which begin with host names (rather than 841 names which begin with host names (rather than IP addresses) requires
830 a user space helper (such as cifs.upcall) to b 842 a user space helper (such as cifs.upcall) to be present in order to
831 translate host names to ip address, and the us 843 translate host names to ip address, and the user space helper must also
832 be configured in the file /etc/request-key.con 844 be configured in the file /etc/request-key.conf. Samba, Windows servers and
833 many NAS appliances support DFS as a way of co 845 many NAS appliances support DFS as a way of constructing a global name
834 space to ease network configuration and improv 846 space to ease network configuration and improve reliability.
835 847
836 To use cifs Kerberos and DFS support, the Linu 848 To use cifs Kerberos and DFS support, the Linux keyutils package should be
837 installed and something like the following lin 849 installed and something like the following lines should be added to the
838 /etc/request-key.conf file:: 850 /etc/request-key.conf file::
839 851
840 create cifs.spnego * * /usr/local/sbin/cifs. 852 create cifs.spnego * * /usr/local/sbin/cifs.upcall %k
841 create dns_resolver * * /usr/local/sbin/cifs 853 create dns_resolver * * /usr/local/sbin/cifs.upcall %k
842 854
843 CIFS kernel module parameters 855 CIFS kernel module parameters
844 ============================= 856 =============================
845 These module parameters can be specified or mo 857 These module parameters can be specified or modified either during the time of
846 module loading or during the runtime by using 858 module loading or during the runtime by using the interface::
847 859
848 /sys/module/cifs/parameters/<param> !! 860 /proc/module/cifs/parameters/<param>
849 861
850 i.e.:: 862 i.e.::
851 863
852 echo "value" > /sys/module/cifs/parameters 864 echo "value" > /sys/module/cifs/parameters/<param>
853 <<
854 More detailed descriptions of the available mo <<
855 can be seen by doing: <<
856 <<
857 modinfo cifs (or modinfo smb3) <<
858 865
859 ================= ============================ 866 ================= ==========================================================
860 1. enable_oplocks Enable or disable oplocks. O 867 1. enable_oplocks Enable or disable oplocks. Oplocks are enabled by default.
861 [Y/y/1]. To disable use any 868 [Y/y/1]. To disable use any of [N/n/0].
862 ================= ============================ 869 ================= ==========================================================
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