1.\" Copyright (c) 1980, 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)mount.8 8.8 (Berkeley) 6/16/94 33.\" $FreeBSD$ 34.\" 35.Dd June 16, 1994 36.Dt MOUNT 8 37.Os BSD 4 38.Sh NAME 39.Nm mount 40.Nd mount file systems 41.Sh SYNOPSIS 42.Nm mount 43.Op Fl adfpruvw 44.Op Fl t Ar ufs | lfs | external_type 45.Nm mount 46.Op Fl dfpruvw 47.Ar special | node 48.Nm mount 49.Op Fl dfpruvw 50.Op Fl o Ar options 51.Op Fl t Ar ufs | lfs | external_type 52.Ar special node 53.Sh DESCRIPTION 54The 55.Nm 56command 57calls the 58.Xr mount 2 59system call to prepare and graft a 60.Ar "special device" 61or the remote node (rhost:path) on to the file system tree at the point 62.Ar node . 63If either 64.Ar special 65or 66.Ar node 67are not provided, the appropriate information is taken from the 68.Xr fstab 5 69file. 70.Pp 71The system maintains a list of currently mounted file systems. 72If no arguments are given to 73.Nm mount , 74this list is printed. 75.Pp 76The options are as follows: 77.Bl -tag -width indent 78.It Fl a 79All the filesystems described in 80.Xr fstab 5 81are mounted. 82Exceptions are those marked as ``noauto'', excluded by the 83.Fl t 84flag (see below), or if they are already mounted (except the 85root filesystem which is always remounted to preserve 86traditional single user mode behavior). 87.It Fl d 88Causes everything to be done except for the actual system call. 89This option is useful in conjunction with the 90.Fl v 91flag to 92determine what the 93.Nm 94command is trying to do. 95.It Fl f 96Forces the revocation of write access when trying to downgrade 97a filesystem mount status from read-write to read-only. Also 98forces the R/W mount of an unclean filesystem (dangerous; use with 99caution). 100.It Fl o 101Options are specified with a 102.Fl o 103flag followed by a comma separated string of options. 104In case of conflicting options being specified, the rightmost option 105takes effect. 106The following options are available: 107.Bl -tag -width indent 108.It async 109All 110.Tn I/O 111to the file system should be done asynchronously. 112This is a 113.Em dangerous 114flag to set, 115and should not be used unless you are prepared to recreate the file 116system should your system crash. 117.It current 118When used with the 119.Fl u 120flag, this is the same as specifying the options currently in effect for 121the mounted filesystem. 122.It force 123The same as 124.Fl f ; 125forces the revocation of write access when trying to downgrade 126a filesystem mount status from read-write to read-only. Also 127forces the R/W mount of an unclean filesystem (dangerous; use with caution). 128.It fstab 129When used with the 130.Fl u 131flag, this is the same as specifying all the options listed in the 132.Xr fstab 5 133file for the filesystem. 134.It noatime 135Do not update the file access time when reading from a file. This option 136is useful on filesystems where there are large numbers of files and 137performance is more critical than updating the file access time (which is 138rarely ever important). This option is currently only supported on local 139filesystems. 140.It noauto 141This filesystem should be skipped when mount is run with the 142.Fl a 143flag. 144.It noclusterr 145Disable read clustering. 146.It noclusterw 147Disable write clustering. 148.It nodev 149Do not interpret character or block special devices on the file system. 150This option is useful for a server that has file systems containing 151special devices for architectures other than its own. 152.It noexec 153Do not allow execution of any binaries on the mounted file system. 154This option is useful for a server that has file systems containing 155binaries for architectures other than its own. 156.It nosuid 157Do not allow set-user-identifier or set-group-identifier bits to take effect. 158Note: this option is worthless if a public available suid or sgid 159wrapper like 160.Xr suidperl 1 161is installed on your system. 162.It nosymfollow 163Do not follow symlinks 164on the mounted file system. 165.It rdonly 166The same as 167.Fl r ; 168mount the file system read-only (even the super-user may not write it). 169.It sync 170All 171.Tn I/O 172to the file system should be done synchronously. 173.It suiddir 174A directory on the mounted filesystem will respond to the SUID bit 175being set, by setting the owner of any new files to be the same 176as the owner of the directory. 177New directories will inherit the bit from their parents. 178Execute bits are removed from 179the file, and it will not be given to root. 180.Pp 181This feature is designed for use on fileservers serving PC users via 182ftp, SAMBA, or netatalk. It provides security holes for shell users and as 183such should not be used on shell machines, especially on home directories. 184This option requires the SUIDDIR 185option in the kernel to work. Only UFS filesystems support this option. 186See 187.Xr chmod 2 188for more information. 189.It update 190The same as 191.Fl u ; 192indicate that the status of an already mounted file system should be changed. 193.It union 194Causes the namespace at the mount point to appear as the union 195of the mounted filesystem root and the existing directory. 196Lookups will be done in the mounted filesystem first. 197If those operations fail due to a non-existent file the underlying 198directory is then accessed. 199All creates are done in the mounted filesystem. 200.El 201.Pp 202Any additional options specific to a filesystem type that is not 203one of the internally known types (see the 204.Fl t 205option) may be passed as a comma separated list; these options are 206distinguished by a leading 207.Dq \&- 208(dash). 209Options that take a value are specified using the syntax -option=value. 210For example, the 211.Nm 212command: 213.Bd -literal -offset indent 214mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp 215.Ed 216.Pp 217causes 218.Nm 219to execute the equivalent of: 220.Bd -literal -offset indent 221/sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp 222.Ed 223.It Fl p 224Print mount information in fstab format. Implies also the 225.Fl v 226option. 227.It Fl r 228The file system is to be mounted read-only. 229Mount the file system read-only (even the super-user may not write it). 230The same as the 231.Dq rdonly 232argument to the 233.Fl o 234option. 235.It Fl t Ar "ufs \\*(Ba lfs \\*(Ba external type" 236The argument following the 237.Fl t 238is used to indicate the file system type. 239The type 240.Ar ufs 241is the default. 242The 243.Fl t 244option can be used 245to indicate that the actions should only be taken on 246filesystems of the specified type. 247More than one type may be specified in a comma separated list. 248The list of filesystem types can be prefixed with 249.Dq no 250to specify the filesystem types for which action should 251.Em not 252be taken. 253For example, the 254.Nm 255command: 256.Bd -literal -offset indent 257mount -a -t nonfs,mfs 258.Ed 259.Pp 260mounts all filesystems except those of type 261.Tn NFS 262and 263.Tn MFS . 264.Pp 265If the type is not one of the internally known types, 266.Nm 267will attempt to execute a program in 268.Pa /sbin/mount_ Ns Em XXX 269where 270.Em XXX 271is replaced by the type name. 272For example, nfs filesystems are mounted by the program 273.Pa /sbin/mount_nfs . 274.Pp 275Most filesystems will be dynamically loaded by their mount programs 276if not already present in the kernel, using the 277.Xr vfsload 3 278subroutine. Because this mechanism requires writable temporary space, 279the filesystem type containing 280.Pa /tmp 281must be compiled into the kernel, and the filesystems containing 282.Pa /tmp 283and 284.Pa /usr/bin/ld 285must be listed in 286.Pa /etc/fstab 287before any filesystems which might be dynamically loaded. 288.It Fl u 289The 290.Fl u 291flag indicates that the status of an already mounted file 292system should be changed. 293Any of the options discussed above (the 294.Fl o 295option) 296may be changed; 297also a file system can be changed from read-only to read-write 298or vice versa. 299An attempt to change from read-write to read-only will fail if any 300files on the filesystem are currently open for writing unless the 301.Fl f 302flag is also specified. 303The set of options is determined by applying the options specified 304in the argument to 305.Fl o 306and finally applying the 307.Fl r 308or 309.Fl w 310option. 311.It Fl v 312Verbose mode. 313.It Fl w 314The file system object is to be read and write. 315.Pp 316The options specific to NFS filesystems are described in the 317.Xr mount_nfs 8 318manual page. 319.Sh DIAGNOSTICS 320Various, most of them are self-explanatory. 321.Pp 322.Dl XXXXX filesystem is not available 323.Pp 324The kernel doesn't support the respective filesystem type. Note that 325support for a particular filesystem might be provided either on a static 326(kernel compile-time), or dynamic basis (loaded as a kernel module by 327.Xr kldload 8 ). 328Normally, 329.Nm 330or its subprocesses attempt to dynamically load a filesystem module if 331it hasn't been configured statically, using 332.Xr vfsload 3 . 333In this case, the above error message can also mean that you didn't 334have permission to load the module. 335.Sh FILES 336.Bl -tag -width /etc/fstab -compact 337.It Pa /etc/fstab 338file system table 339.El 340.Sh SEE ALSO 341.Xr mount 2 , 342.Xr vfsload 3 , 343.Xr fstab 5 , 344.Xr kldload 8 , 345.Xr mount_cd9660 8 , 346.Xr mount_devfs 8 , 347.Xr mount_fdesc 8 , 348.Xr mount_kernfs 8 , 349.Xr mount_lfs 8 , 350.Xr mount_mfs 8 , 351.Xr mount_msdos 8 , 352.Xr mount_nfs 8 , 353.Xr mount_null 8 , 354.Xr mount_portal 8 , 355.Xr mount_procfs 8 , 356.Xr mount_umap 8 , 357.Xr mount_union 8 , 358.Xr umount 8 359.Sh BUGS 360It is possible for a corrupted file system to cause a crash. 361.Pp 362Switching a filesystem back and forth between asynchronous and normal 363operation or between read/write and read/only access using ``mount 364-u'' may gradually bring about severe filesystem corruption. 365.Sh CAVEATS 366After a successful mount, the permissions on the original mount point 367determine if 368.Pa ".." 369is accessible from the mounted file system. The minimum permissions for 370the mount point for traversal across the mount point in both 371directions to be possible for all users is 0111 (execute for all). 372.Sh HISTORY 373A 374.Nm 375command appeared in 376.At v1 . 377