1.\" $NetBSD: mount.8,v 1.52 2006/02/12 01:32:06 chs Exp $ 2.\" 3.\" Copyright (c) 1980, 1989, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)mount.8 8.8 (Berkeley) 6/16/94 31.\" 32.Dd February 11, 2006 33.Dt MOUNT 8 34.Os 35.Sh NAME 36.Nm mount 37.Nd mount file systems 38.Sh SYNOPSIS 39.Nm 40.Op Fl Aadfruvw 41.Op Fl t Ar type 42.Nm 43.Op Fl dfruvw 44.Ar special | node 45.Nm 46.Op Fl dfruvw 47.Op Fl o Ar options 48.Op Fl t Ar type 49.Ar special node 50.Sh DESCRIPTION 51The 52.Nm 53command invokes a file system-specific program to prepare and graft the 54.Ar special 55device or remote node (rhost:path) on to the file system tree at the point 56.Ar node . 57.Pp 58If either 59.Ar special 60or 61.Ar node 62are not provided, the appropriate information is taken from the 63.Xr fstab 5 64file. 65The provided argument is looked up first in the 66.Dq fs_file , 67then in the 68.Dq fs_spec 69column. 70If the matching entry in 71.Xr fstab 5 72has the string 73.Dq Li from_mount 74as its 75.Dq fs_spec 76field, the device or remote file system already mounted at 77the location specified by 78.Dq fs_spec 79will be used. 80.Pp 81If both 82.Ar special 83and 84.Ar node 85are given, the disklabel is checked for the file system type. 86.Pp 87In 88.Nx , 89a file system can only be mounted by an ordinary user who owns the 90point 91.Ar node 92and has access to the 93.Ar special 94device (at least read permissions). 95In addition, the 96.Em vfs.generic.usermount 97.Xr sysctl 3 98must be set to 1 to permit file system mounting by ordinary users. 99See also 100.Xr sysctl 8 . 101.Pp 102The system maintains a list of currently mounted file systems. 103If no arguments are given to 104.Nm , 105this list is printed. 106.Pp 107The options are as follows: 108.Bl -tag -width indent 109.It Fl A 110Causes 111.Nm 112to try to mount all of the file systems listed in the 113.Xr fstab 5 114file except those for which the 115.Dq noauto 116option is specified. 117.It Fl a 118Similar to the 119.Fl A 120flag, except that if a file system (other than the root file system) 121appears to be already mounted, 122.Nm 123will not try to mount it again. 124.Nm 125assumes that a file system is already mounted if a file system with 126the same type is mounted on the given mount point. 127More stringent checks are not possible because some file system types 128report strange values for the mounted-from device for mounted file 129systems. 130.It Fl d 131Causes everything to be done except for the invocation of 132the file system-specific program. 133This option is useful in conjunction with the 134.Fl v 135flag to determine what the 136.Nm 137command is trying to do. 138.It Fl f 139Forces the revocation of write access when trying to downgrade 140a file system mount status from read-write to read-only. 141.It Fl o 142Options are specified with a 143.Fl o 144flag followed by a comma separated string of options. 145The following options are available: 146.Bl -tag -width nocoredump 147.It Cm async 148All 149.Tn I/O 150to the file system should be done asynchronously. 151In the event of a crash, 152.Em "it is impossible for the system to verify the integrity of data on a file system mounted with this option" . 153You should only use this option if you have an application-specific data 154recovery mechanism, or are willing to recreate the file system from scratch. 155.It Cm noasync 156Clear 157.Cm async 158mode. 159.It Cm force 160The same as 161.Fl f ; 162forces the revocation of write access when trying to downgrade 163a file system mount status from read-write to read-only. 164.It Cm getargs 165Retrieves the file system specific mount arguments for the given 166mounted file system and prints them. 167.It Cm hidden 168By setting the 169.Dv MNT_IGNORE 170flag, 171causes the mount point to be excluded from the 172list of file systems shown by default with 173.Xr df 1 . 174.It Cm noatime 175Never update the access time field for files. 176This option is useful for optimizing read performance on file systems 177that are used as news spools. 178.It Cm noauto 179This file system should be skipped when mount is run with the 180.Fl a 181flag. 182.It Cm nocoredump 183Do not allow programs to create crash dumps (core files) on the file system. 184This option can be used to help protect sensitive 185data by keeping core files (which may contain sensitive data) 186from being created on insecure file systems. 187Only core files that would be created by program crashes are 188prevented by use of this flag; the behavior of 189.Xr savecore 8 190is not affected. 191.It Cm nodev 192Do not interpret character or block special devices on the file system. 193This option is useful for a server that has file systems containing 194special devices for architectures other than its own. 195.It Cm nodevmtime 196Do not update modification times on device special files. 197This option is useful on laptops 198or other systems that perform power management. 199.It Cm noexec 200Do not allow execution of any binaries on the mounted file system. 201This option is useful for a server that has file systems containing 202binaries for architectures other than its own. 203.It Cm nosuid 204Do not allow set-user-identifier or set-group-identifier bits to take effect. 205.It Cm port 206(NFS only) Use the specified NFS port. 207.It Cm rdonly 208The same as 209.Fl r ; 210mount the file system read-only (even the super-user may not write it). 211.It Cm reload 212Reload all incore data for a file system. 213This is used mainly after running 214.Xr fsck 8 215on the root file system and finding things to fix. 216The file system must be mounted read-only. 217All cached meta-data are invalidated, superblock and summary information 218is re-read from disk, all cached inactive vnodes and file data are 219invalidated and all inode data are re-read for all active vnodes. 220.It Cm softdep 221(FFS only) Mount the file system using soft dependencies. 222This means that metadata will not be written immediately, 223but is written in an ordered fashion to keep the 224on-disk state of the file system consistent. 225This results in significant speedups for file create/delete operations. 226This option will be ignored when using the 227.Fl u 228flag and a file system is already mounted read/write. 229This option has gone through moderate to heavy testing, 230but should still be used with care. 231A file system mounted with 232.Cm softdep 233can not be mounted with 234.Cm async . 235It requires the 236.Dv SOFTDEP 237option to be enabled in the running kernel. 238.It Cm symperm 239Recognize permission of symbolic link when reading or traversing link. 240.It Cm sync 241All 242.Tn I/O 243to the file system should be done synchronously. 244This is not equivalent to the normal mode in which only 245metadata is written synchronously. 246.It Cm nosync 247Clear 248.Cm sync 249mode. 250.It Cm union 251Causes the namespace at the mount point to appear as the union 252of the mounted file system root and the existing directory. 253Lookups will be done in the mounted file system first. 254If those operations fail due to a non-existent file the underlying 255directory is then accessed. 256All creates are done in the mounted file system, except for the fdesc 257file system. 258.It Cm update 259The same as 260.Fl u ; 261indicate that the status of an already mounted file system should be changed. 262.El 263.Pp 264Any additional options specific to a given file system type (see the 265.Fl t 266option) may be passed as a comma separated list; these options are 267distinguished by a leading 268.Dq \&- 269(dash). 270Options that take a value are specified using the syntax -option=value. 271For example, the mount command: 272.Bd -literal -offset indent 273mount -t mfs -o nosuid,-N,-s=32m swap /tmp 274.Ed 275.Pp 276causes 277.Nm 278to execute the equivalent of: 279.Bd -literal -offset indent 280/sbin/mount_mfs -o nosuid -N -s 32m swap /tmp 281.Ed 282.It Fl r 283The file system is to be mounted read-only. 284Mount the file system read-only (even the super-user may not write it). 285The same as the 286.Dq rdonly 287argument to the 288.Fl o 289option. 290.It Fl t Ar type 291The argument following the 292.Fl t 293is used to indicate the file system type. 294The type 295.Ar ffs 296is the default. 297The 298.Fl t 299option can be used to indicate that the actions 300should only be taken on file systems of the specified type. 301More than one type may be specified in a comma separated list. 302The list of file system types can be prefixed with 303.Dq no 304to specify the file system types for which action should 305.Em not 306be taken. 307For example, the 308.Nm 309command: 310.Bd -literal -offset indent 311mount -a -t nonfs,mfs 312.Ed 313.Pp 314mounts all file systems except those of type 315.Tn NFS 316and 317.Tn MFS . 318.Pp 319.Nm 320will attempt to execute a program in 321.Pa /sbin/mount_ Ns Em XXX 322where 323.Em XXX 324is replaced by the type name. 325For example, nfs file systems are mounted by the program 326.Pa /sbin/mount_nfs . 327.It Fl u 328The 329.Fl u 330flag indicates that the status of an already mounted file 331system should be changed. 332Any of the options discussed above (the 333.Fl o 334option) 335may be changed; 336also a file system can be changed from read-only to read-write 337or vice versa. 338An attempt to change from read-write to read-only will fail if any 339files on the file system are currently open for writing unless the 340.Fl f 341flag is also specified. 342The set of options is determined by first extracting the options 343for the file system from the 344.Xr fstab 5 345file, then applying any options specified by the 346.Fl o 347argument, 348and finally applying the 349.Fl r 350or 351.Fl w 352option. 353.It Fl v 354Verbose mode. 355If this flag is specified more than once, then the 356file system-specific mount arguments are printed for the given mounted 357file system. 358.It Fl w 359The file system object is to be read and write. 360.El 361.Pp 362The options specific to the various file system types are 363described in the manual pages for those file systems' 364.Nm mount_XXX 365commands. 366For instance the options specific to Berkeley 367Fast File System (FFS) are described in the 368.Xr mount_ffs 8 369manual page. 370.Pp 371The particular type of file system in each partition of a disk can 372be found by examining the disk label with the 373.Xr disklabel 8 374command. 375.Sh FILES 376.Bl -tag -width /etc/fstab -compact 377.It Pa /etc/fstab 378file system table 379.El 380.Sh EXAMPLES 381Some useful examples: 382.Pp 383.Bl -hang -offset indent -width "MS-DOS" 384.It Tn CD-ROM 385.br 386mount -t cd9660 -r /dev/cd0a /cdrom 387.It Tn MS-DOS 388.br 389mount -t msdos /dev/fd0a /floppy 390.It Tn NFS 391.br 392mount nfs-server-host:/directory/path /mount-point 393.It Tn MFS (32 megabyte) 394.br 395mount -t mfs -o nosuid,-s=32m swap /tmp 396.El 397.Pp 398The 399.Dq noauto 400directive in 401.Pa /etc/fstab 402can be used to make it easy to manually mount and unmount removable 403media using just the mountpoint filename, with an entry like this: 404.Pp 405.Dl /dev/cd0a /cdrom cd9660 ro,noauto 0 0 406.Pp 407That would allow a simple command like 408.Qq mount /cdrom 409or 410.Qq umount /cdrom 411for media using the 412.Tn ISO-9660 413file system format in the first 414.Tn CD-ROM 415drive. 416.Sh SEE ALSO 417.Xr df 1 , 418.Xr mount 2 , 419.Xr fstab 5 , 420.Xr disklabel 8 , 421.Xr fsck 8 , 422.Xr mount_ados 8 , 423.Xr mount_cd9660 8 , 424.Xr mount_ext2fs 8 , 425.Xr mount_fdesc 8 , 426.Xr mount_ffs 8 , 427.Xr mount_filecore 8 , 428.Xr mount_kernfs 8 , 429.Xr mount_lfs 8 , 430.Xr mount_mfs 8 , 431.Xr mount_msdos 8 , 432.Xr mount_nfs 8 , 433.Xr mount_ntfs 8 , 434.Xr mount_null 8 , 435.Xr mount_overlay 8 , 436.Xr mount_portal 8 , 437.Xr mount_procfs 8 , 438.Xr mount_udf 8 , 439.Xr mount_umap 8 , 440.Xr mount_union 8 , 441.Xr umount 8 442.Sh HISTORY 443A 444.Nm 445command appeared in 446.At v6 . 447