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28 .\" @(#)mount.8 8.8 (Berkeley) 6/16/94
29 .\" $FreeBSD: src/sbin/mount/mount.8,v 1.31.2.12 2003/02/23 21:17:42 trhodes Exp $
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31 .Dd May 15, 2016
32 .Dt MOUNT 8
33 .Os
34 .Sh NAME
35 .Nm mount
36 .Nd mount file systems
37 .Sh SYNOPSIS
38 .Nm
39 .Op Fl adfpruvw
40 .Op Fl F Ar fstab
41 .Op Fl o Ar options
42 .Op Fl t Ar type
43 .Nm
44 .Op Fl dfpruvw
45 .Brq Ar special | node
46 .Nm
47 .Op Fl dfpruvw
48 .Op Fl o Ar options
49 .Op Fl t Ar type
50 .Ar special node
51 .Sh DESCRIPTION
52 The
53 .Nm
54 utility calls the
55 .Xr mount 2
56 system call to prepare and graft a
57 .Ar "special device"
58 or the remote node (rhost:path) on to the file system tree at the point
59 .Ar node .
60 If either
61 .Ar special
62 or
63 .Ar node
64 are not provided, the appropriate information is taken from the
65 .Xr fstab 5
66 file.
67 .Pp
68 The system maintains a list of currently mounted file systems.
69 If no arguments are given to
70 .Nm ,
71 this list is printed.
72 .Pp
73 The options are as follows:
74 .Bl -tag -width indent
75 .It Fl a
76 All the filesystems described in
77 .Xr fstab 5
78 are mounted.
79 Exceptions are those marked as
80 .Dq noauto ,
81 excluded by the
82 .Fl t
83 flag (see below), or if they are already mounted (except the
84 root filesystem which is always remounted to preserve
85 traditional single user mode behavior).
86 .It Fl d
87 Causes everything to be done except for the actual system call.
88 This option is useful in conjunction with the
89 .Fl v
90 flag to
91 determine what the
92 .Nm
93 command is trying to do.
94 .It Fl F Ar fstab
95 Specify the
96 .Pa fstab
97 file to use.
98 .It Fl f
99 Forces the revocation of write access when trying to downgrade
100 a filesystem mount status from read-write to read-only.
101 Also
102 forces the R/W mount of an unclean filesystem (dangerous; use with
103 caution).
104 .It Fl o
105 Options are specified with a
106 .Fl o
107 flag followed by a comma separated string of options.
108 If a
109 .Dq no
110 prefix is added or removed from a option name, then meaning is negated.
111 In case of conflicting options being specified, the rightmost option
112 takes effect.
113 The following options are available:
114 .Bl -tag -width indent
115 .It Cm async
116 All
117 .Tn I/O
118 to the file system should be done asynchronously.
119 This is a
120 .Em dangerous
121 flag to set,
122 and should not be used unless you are prepared to recreate the file
123 system should your system crash.
124 .It Cm automounted
125 This flag indicates that the file system was mounted by
126 .Xr automountd 8 .
127 Automounted file systems are automatically unmounted by
128 .Xr autounmountd 8 .
129 .It Cm current
130 When used with the
131 .Fl u
132 flag, this is the same as specifying the options currently in effect for
133 the mounted filesystem.
134 .It Cm force
135 The same as
136 .Fl f ;
137 forces the revocation of write access when trying to downgrade
138 a filesystem mount status from read-write to read-only.
139 Also
140 forces the R/W mount of an unclean filesystem (dangerous; use with caution).
141 .It Cm fstab
142 When used with the
143 .Fl u
144 flag, this is the same as specifying all the options listed in the
145 .Xr fstab 5
146 file for the filesystem.
147 .It Cm noasync
148 Metadata I/O should be done synchronously, while data I/O should be done
149 asynchronously.
150 This is the default.
151 .It Cm noatime
152 Do not update the file access time when reading from a file.
153 This option
154 is useful on filesystems where there are large numbers of files and
155 performance is more critical than updating the file access time (which is
156 rarely ever important).
157 This option is currently only supported on local filesystems.
158 .It Cm noauto
159 This filesystem should be skipped when
160 .Nm
161 is run with the
162 .Fl a
163 flag.
164 .It Cm noclusterr
165 Disable read clustering.
166 .It Cm noclusterw
167 Disable write clustering.
168 .It Cm nodev
169 Do not interpret character or block special devices on the file system.
170 This option is useful for a server that has file systems containing
171 special devices for architectures other than its own.
172 This option is set automatically when the user does not have super-user
173 privileges.
174 .It Cm noexec
175 Do not allow execution of any binaries on the mounted file system.
176 This option is useful for a server that has file systems containing
177 binaries for architectures other than its own.
178 .It Cm nosuid
179 Do not allow set-user-identifier or set-group-identifier bits to take effect.
180 Note: this option is worthless if a public available suid or sgid
181 wrapper like
182 .Xr suidperl 1
183 is installed on your system.
184 It is set automatically when the user does not have super-user privileges.
185 .It Cm nosymfollow
186 Do not follow symlinks
187 on the mounted file system.
188 .It Cm rdonly , ro , norw
189 The same as
190 .Fl r ;
191 mount the file system read-only (even the super-user may not write it).
192 .It Cm sync
193 All
194 .Tn I/O
195 to the file system should be done synchronously.
196 .It Cm trim
197 If the device supports TRIM
198 .Va ( kern.cam.da.X.trim_enabled
199 exists) and is set,
200 the file system will perform online trim for corresponding block deletions.
201 Currently, only
202 .Xr UFS 5
203 supports this feature.
204 .It Cm suiddir
205 A directory on the mounted filesystem will respond to the SUID bit
206 being set, by setting the owner of any new files to be the same
207 as the owner of the directory.
208 New directories will inherit the bit from their parents.
209 Execute bits are removed from
210 the file, and it will not be given to root.
211 .Pp
212 This feature is designed for use on fileservers serving PC users via
213 ftp or SAMBA.
214 It provides security holes for shell users and as
215 such should not be used on shell machines, especially on home directories.
216 This option requires the SUIDDIR
217 option in the kernel to work.
218 Only
219 .Xr UFS 5
220 filesystems support this option.
221 See
222 .Xr chmod 2
223 for more information.
224 .It Cm update
225 The same as
226 .Fl u ;
227 indicate that the status of an already mounted file system should be changed.
228 .It Cm ignore
229 Will be ignored by
230 .Xr df 1 .
231 .El
232 .Pp
233 Any additional options specific to a filesystem type that is not
234 one of the internally known types (see the
235 .Fl t
236 option) may be passed as a comma separated list; these options are
237 distinguished by a leading
238 .Dq \&-
239 (dash).
240 Options that take a value are specified using the syntax -option=value.
241 For example, the
242 .Nm
243 command:
244 .Bd -literal -offset indent
245 mount -t mfs -o nosuid,-N,-s=4000 /dev/da0s0b /tmp
246 .Ed
247 .Pp
248 causes
249 .Nm
250 to execute the equivalent of:
251 .Bd -literal -offset indent
252 /sbin/mount_mfs -o nosuid -N -s 4000 /dev/da0s0b /tmp
253 .Ed
254 .Pp
255 Additional options specific to filesystem types
256 which are not internally known
257 (see the description of the
258 .Fl t
259 option below)
260 may be described in the manual pages for the associated
261 .Pa /sbin/mount_ Ns Sy XXX
262 utilities.
263 .It Fl p
264 Print mount information in
265 .Xr fstab 5
266 format.
267 If fstab is missing or if the freq and passno fields are omitted,
268 the default values as described in
269 .Xr fstab 5
270 are used.
271 Implies also the
272 .Fl v
273 option.
274 .It Fl r
275 The file system is to be mounted read-only.
276 Mount the file system read-only (even the super-user may not write it).
277 The same as the
278 .Cm rdonly
279 argument to the
280 .Fl o
281 option.
282 .It Fl t Ar type
283 The argument following the
284 .Fl t
285 is used to indicate the file system type.
286 The type
287 .Cm ufs
288 is the default.
289 The
290 .Fl t
291 option can be used
292 to indicate that the actions should only be taken on
293 filesystems of the specified type.
294 More than one type may be specified in a comma separated list.
295 The list of filesystem types can be prefixed with
296 .Dq no
297 to specify the filesystem types for which action should
298 .Em not
299 be taken.
300 For example, the
301 .Nm
302 command:
303 .Bd -literal -offset indent
304 mount -a -t nonfs,mfs
305 .Ed
306 .Pp
307 mounts all filesystems except those of type
308 .Tn NFS
309 and
310 .Tn MFS .
311 .Pp
312 If the type is not the internally known type,
313 .Cm ufs ,
314 .Nm
315 will attempt to execute a program in
316 .Pa /sbin/mount_ Ns Sy XXX
317 where
318 .Sy XXX
319 is replaced by the type name.
320 For example, nfs filesystems are mounted by the program
321 .Pa /sbin/mount_nfs .
322 .Pp
323 Most filesystems will be dynamically loaded by their
324 .Nm
325 programs
326 if not already present in the kernel, using the
327 .Xr vfsload 3
328 subroutine.
329 Because this mechanism requires writable temporary space,
330 the filesystem type containing
331 .Pa /tmp
332 must be compiled into the kernel, and the filesystems containing
333 .Pa /tmp
334 and
335 .Pa /usr/bin/ld
336 must be listed in
337 .Pa /etc/fstab
338 before any filesystems which might be dynamically loaded.
339 .It Fl u
340 The
341 .Fl u
342 flag indicates that the status of an already mounted file
343 system should be changed.
344 Any of the options discussed above (the
345 .Fl o
346 option)
347 may be changed;
348 also a file system can be changed from read-only to read-write
349 or vice versa.
350 An attempt to change from read-write to read-only will fail if any
351 files on the filesystem are currently open for writing unless the
352 .Fl f
353 flag is also specified.
354 The set of options is determined by applying the options specified
355 in the argument to
356 .Fl o
357 and finally applying the
358 .Fl r
359 or
360 .Fl w
361 option.
362 .It Fl v
363 Verbose mode.
364 .It Fl w
365 The file system object is to be read and write.
366 .El
367 .Sh ENVIRONMENT
368 .Bl -tag -width PATH_FSTAB
369 .It Pa PATH_FSTAB
370 If the environment variable
371 .Pa PATH_FSTAB
372 is set all operations are performed against the specified file.
373 .El
374 .Sh FILES
375 .Bl -tag -width /etc/fstab -compact
376 .It Pa /etc/fstab
377 file system table
378 .El
379 .Sh DIAGNOSTICS
380 Various, most of them are self-explanatory.
381 .Pp
382 .Dl XXXXX filesystem is not available
383 .Pp
384 The kernel does not support the respective filesystem type.
385 Note that
386 support for a particular filesystem might be provided either on a static
387 (kernel compile-time), or dynamic basis (loaded as a kernel module by
388 .Xr kldload 8 ) .
389 Normally,
390 .Nm
391 or its subprocesses attempt to dynamically load a filesystem module if
392 it has not been configured statically, using
393 .Xr vfsload 3 .
394 In this case, the above error message can also mean that you did not
395 have permission to load the module.
396 .Sh SEE ALSO
397 .Xr df 1 ,
398 .Xr lsvfs 1 ,
399 .Xr mount 2 ,
400 .Xr vfsload 3 ,
401 .Xr devtab 5 ,
402 .Xr fstab 5 ,
403 .Xr UFS 5 ,
404 .Xr automount 8 ,
405 .Xr automountd 8 ,
406 .Xr autounmountd 8 ,
407 .Xr kldload 8 ,
408 .Xr mount_cd9660 8 ,
409 .Xr mount_devfs 8 ,
410 .Xr mount_ext2fs 8 ,
411 .Xr mount_hammer 8 ,
412 .Xr mount_hpfs 8 ,
413 .Xr mount_mfs 8 ,
414 .Xr mount_msdos 8 ,
415 .Xr mount_nfs 8 ,
416 .Xr mount_ntfs 8 ,
417 .Xr mount_null 8 ,
418 .Xr mount_procfs 8 ,
419 .Xr mount_smbfs 8 ,
420 .Xr mount_std 8 ,
421 .Xr mount_tmpfs 8 ,
422 .Xr mount_udf 8 ,
423 .Xr sysctl 8 ,
424 .Xr umount 8
425 .Sh HISTORY
426 A
427 .Nm
428 utility appeared in
429 .At v1 .
430 .Sh CAVEATS
431 After a successful
432 .Nm ,
433 the permissions on the original mount point determine if
434 .Pa ..\&
435 is accessible from the mounted file system.
436 The minimum permissions for
437 the mount point for traversal across the mount point in both
438 directions to be possible for all users is 0111 (execute for all).
439 .Sh BUGS
440 It is possible for a corrupted file system to cause a crash.