File:  [DragonFly] / src / sbin / mount / mount.8
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   32: .\"     @(#)mount.8	8.8 (Berkeley) 6/16/94
   33: .\" $FreeBSD: src/sbin/mount/mount.8,v 1.31.2.12 2003/02/23 21:17:42 trhodes Exp $
   34: .\" $DragonFly: src/sbin/mount/mount.8,v 1.2 2003/06/17 04:27:33 dillon Exp $
   35: .\"
   36: .Dd June 16, 1994
   37: .Dt MOUNT 8
   38: .Os
   39: .Sh NAME
   40: .Nm mount
   41: .Nd mount file systems
   42: .Sh SYNOPSIS
   43: .Nm
   44: .Op Fl adfpruvw
   45: .Op Fl t Ar ufs | external_type
   46: .Nm
   47: .Op Fl dfpruvw
   48: .Ar special | node
   49: .Nm
   50: .Op Fl dfpruvw
   51: .Op Fl o Ar options
   52: .Op Fl t Ar ufs | external_type
   53: .Ar special node
   54: .Sh DESCRIPTION
   55: The
   56: .Nm
   57: utility calls the
   58: .Xr mount 2
   59: system call to prepare and graft a
   60: .Ar "special device"
   61: or the remote node (rhost:path) on to the file system tree at the point
   62: .Ar node .
   63: If either
   64: .Ar special
   65: or
   66: .Ar node
   67: are not provided, the appropriate information is taken from the
   68: .Xr fstab 5
   69: file.
   70: .Pp
   71: The system maintains a list of currently mounted file systems.
   72: If no arguments are given to
   73: .Nm ,
   74: this list is printed.
   75: .Pp
   76: The options are as follows:
   77: .Bl -tag -width indent
   78: .It Fl a
   79: All the filesystems described in
   80: .Xr fstab 5
   81: are mounted.
   82: Exceptions are those marked as
   83: .Dq noauto ,
   84: excluded by the
   85: .Fl t
   86: flag (see below), or if they are already mounted (except the
   87: root filesystem which is always remounted to preserve
   88: traditional single user mode behavior).
   89: .It Fl d
   90: Causes everything to be done except for the actual system call.
   91: This option is useful in conjunction with the
   92: .Fl v
   93: flag to
   94: determine what the
   95: .Nm
   96: command is trying to do.
   97: .It Fl f
   98: Forces the revocation of write access when trying to downgrade
   99: a filesystem mount status from read-write to read-only.
  100: Also
  101: forces the R/W mount of an unclean filesystem (dangerous; use with
  102: caution).
  103: .It Fl o
  104: Options are specified with a
  105: .Fl o
  106: flag followed by a comma separated string of options.
  107: In case of conflicting options being specified, the rightmost option
  108: takes effect.
  109: The following options are available:
  110: .Bl -tag -width indent
  111: .It Cm async
  112: All
  113: .Tn I/O
  114: to the file system should be done asynchronously.
  115: This is a
  116: .Em dangerous
  117: flag to set,
  118: and should not be used unless you are prepared to recreate the file
  119: system should your system crash.
  120: .It Cm current
  121: When used with the
  122: .Fl u
  123: flag, this is the same as specifying the options currently in effect for
  124: the mounted filesystem.
  125: .It Cm force
  126: The same as
  127: .Fl f ;
  128: forces the revocation of write access when trying to downgrade
  129: a filesystem mount status from read-write to read-only.
  130: Also
  131: forces the R/W mount of an unclean filesystem (dangerous; use with caution).
  132: .It Cm fstab
  133: When used with the
  134: .Fl u
  135: flag, this is the same as specifying all the options listed in the
  136: .Xr fstab 5
  137: file for the filesystem.
  138: .It Cm noasync
  139: Metadata I/O should be done synchronously, while data I/O should be done
  140: asynchronously.
  141: This is the default.
  142: .It Cm noatime
  143: Do not update the file access time when reading from a file.
  144: This option
  145: is useful on filesystems where there are large numbers of files and
  146: performance is more critical than updating the file access time (which is
  147: rarely ever important).
  148: This option is currently only supported on local filesystems.
  149: .It Cm noauto
  150: This filesystem should be skipped when
  151: .Nm
  152: is run with the
  153: .Fl a
  154: flag.
  155: .It Cm noclusterr
  156: Disable read clustering.
  157: .It Cm noclusterw
  158: Disable write clustering.
  159: .It Cm nodev
  160: Do not interpret character or block special devices on the file system.
  161: This option is useful for a server that has file systems containing
  162: special devices for architectures other than its own.
  163: This option is set automatically when the user does not have super-user
  164: privileges.
  165: .It Cm noexec
  166: Do not allow execution of any binaries on the mounted file system.
  167: This option is useful for a server that has file systems containing
  168: binaries for architectures other than its own.
  169: .It Cm nosuid
  170: Do not allow set-user-identifier or set-group-identifier bits to take effect.
  171: Note: this option is worthless if a public available suid or sgid
  172: wrapper like
  173: .Xr suidperl 1
  174: is installed on your system.
  175: It is set automatically when the user does not have super-user privileges.
  176: .It Cm nosymfollow
  177: Do not follow symlinks
  178: on the mounted file system.
  179: .It Cm rdonly
  180: The same as
  181: .Fl r ;
  182: mount the file system read-only (even the super-user may not write it).
  183: .It Cm sync
  184: All
  185: .Tn I/O
  186: to the file system should be done synchronously.
  187: .It Cm suiddir
  188: A directory on the mounted filesystem will respond to the SUID bit
  189: being set, by setting the owner of any new files to be the same
  190: as the owner of the directory.
  191: New directories will inherit the bit from their parents.
  192: Execute bits are removed from
  193: the file, and it will not be given to root.
  194: .Pp
  195: This feature is designed for use on fileservers serving PC users via
  196: ftp, SAMBA, or netatalk.
  197: It provides security holes for shell users and as
  198: such should not be used on shell machines, especially on home directories.
  199: This option requires the SUIDDIR
  200: option in the kernel to work.
  201: Only UFS filesystems support this option.
  202: See
  203: .Xr chmod 2
  204: for more information.
  205: .It Cm update
  206: The same as
  207: .Fl u ;
  208: indicate that the status of an already mounted file system should be changed.
  209: .It Cm union
  210: Causes the namespace at the mount point to appear as the union
  211: of the mounted filesystem root and the existing directory.
  212: Lookups will be done in the mounted filesystem first.
  213: If those operations fail due to a non-existent file the underlying
  214: directory is then accessed.
  215: All creates are done in the mounted filesystem.
  216: .El
  217: .Pp
  218: Any additional options specific to a filesystem type that is not
  219: one of the internally known types (see the
  220: .Fl t
  221: option) may be passed as a comma separated list; these options are
  222: distinguished by a leading
  223: .Dq \&-
  224: (dash).
  225: Options that take a value are specified using the syntax -option=value.
  226: For example, the
  227: .Nm
  228: command:
  229: .Bd -literal -offset indent
  230: mount -t mfs -o nosuid,-N,-s=4000 /dev/dk0b /tmp
  231: .Ed
  232: .Pp
  233: causes
  234: .Nm
  235: to execute the equivalent of:
  236: .Bd -literal -offset indent
  237: /sbin/mount_mfs -o nosuid -N -s 4000 /dev/dk0b /tmp
  238: .Ed
  239: .Pp
  240: Additional options specific to filesystem types
  241: which are not internally known
  242: (see the description of the
  243: .Fl t
  244: option below)
  245: may be described in the manual pages for the associated
  246: .Pa /sbin/mount_ Ns Sy XXX
  247: utilities.
  248: .It Fl p
  249: Print mount information in
  250: .Xr fstab 5
  251: format.
  252: Implies also the
  253: .Fl v
  254: option.
  255: .It Fl r
  256: The file system is to be mounted read-only.
  257: Mount the file system read-only (even the super-user may not write it).
  258: The same as the
  259: .Cm rdonly
  260: argument to the
  261: .Fl o
  262: option.
  263: .It Fl t Ar ufs | external_type
  264: The argument following the
  265: .Fl t
  266: is used to indicate the file system type.
  267: The type
  268: .Ar ufs
  269: is the default.
  270: The
  271: .Fl t
  272: option can be used
  273: to indicate that the actions should only be taken on
  274: filesystems of the specified type.
  275: More than one type may be specified in a comma separated list.
  276: The list of filesystem types can be prefixed with
  277: .Dq no
  278: to specify the filesystem types for which action should
  279: .Em not
  280: be taken.
  281: For example, the
  282: .Nm
  283: command:
  284: .Bd -literal -offset indent
  285: mount -a -t nonfs,mfs
  286: .Ed
  287: .Pp
  288: mounts all filesystems except those of type
  289: .Tn NFS
  290: and
  291: .Tn MFS .
  292: .Pp
  293: If the type is not one of the internally known types,
  294: .Nm
  295: will attempt to execute a program in
  296: .Pa /sbin/mount_ Ns Sy XXX
  297: where
  298: .Sy XXX
  299: is replaced by the type name.
  300: For example, nfs filesystems are mounted by the program
  301: .Pa /sbin/mount_nfs .
  302: .Pp
  303: Most filesystems will be dynamically loaded by their
  304: .Nm
  305: programs
  306: if not already present in the kernel, using the
  307: .Xr vfsload 3
  308: subroutine.
  309: Because this mechanism requires writable temporary space,
  310: the filesystem type containing
  311: .Pa /tmp
  312: must be compiled into the kernel, and the filesystems containing
  313: .Pa /tmp
  314: and
  315: .Pa /usr/bin/ld
  316: must be listed in
  317: .Pa /etc/fstab
  318: before any filesystems which might be dynamically loaded.
  319: .It Fl u
  320: The
  321: .Fl u
  322: flag indicates that the status of an already mounted file
  323: system should be changed.
  324: Any of the options discussed above (the
  325: .Fl o
  326: option)
  327: may be changed;
  328: also a file system can be changed from read-only to read-write
  329: or vice versa.
  330: An attempt to change from read-write to read-only will fail if any
  331: files on the filesystem are currently open for writing unless the
  332: .Fl f
  333: flag is also specified.
  334: The set of options is determined by applying the options specified
  335: in the argument to
  336: .Fl o
  337: and finally applying the
  338: .Fl r
  339: or
  340: .Fl w
  341: option.
  342: .It Fl v
  343: Verbose mode.
  344: .It Fl w
  345: The file system object is to be read and write.
  346: .El
  347: .Sh DIAGNOSTICS
  348: Various, most of them are self-explanatory.
  349: .Pp
  350: .Dl XXXXX filesystem is not available
  351: .Pp
  352: The kernel does not support the respective filesystem type.
  353: Note that
  354: support for a particular filesystem might be provided either on a static
  355: (kernel compile-time), or dynamic basis (loaded as a kernel module by
  356: .Xr kldload 8 ) .
  357: Normally,
  358: .Nm
  359: or its subprocesses attempt to dynamically load a filesystem module if
  360: it has not been configured statically, using
  361: .Xr vfsload 3 .
  362: In this case, the above error message can also mean that you did not
  363: have permission to load the module.
  364: .Sh FILES
  365: .Bl -tag -width /etc/fstab -compact
  366: .It Pa /etc/fstab
  367: file system table
  368: .El
  369: .Sh SEE ALSO
  370: .Xr mount 2 ,
  371: .Xr vfsload 3 ,
  372: .Xr fstab 5 ,
  373: .Xr kldload 8 ,
  374: .Xr mount_cd9660 8 ,
  375: .Xr mount_ext2fs 8 ,
  376: .Xr mount_fdesc 8 ,
  377: .Xr mount_linprocfs 8 ,
  378: .Xr mount_mfs 8 ,
  379: .Xr mount_msdos 8 ,
  380: .Xr mount_nfs 8 ,
  381: .Xr mount_ntfs 8 ,
  382: .Xr mount_null 8 ,
  383: .Xr mount_nwfs 8 ,
  384: .Xr mount_portal 8 ,
  385: .Xr mount_procfs 8 ,
  386: .Xr mount_smbfs 8 ,
  387: .Xr mount_std 8 ,
  388: .Xr mount_umap 8 ,
  389: .Xr mount_union 8 ,
  390: .Xr sysctl 8 ,
  391: .Xr umount 8
  392: .Sh BUGS
  393: It is possible for a corrupted file system to cause a crash.
  394: .Sh CAVEATS
  395: After a successful
  396: .Nm ,
  397: the permissions on the original mount point determine if
  398: .Pa ..\&
  399: is accessible from the mounted file system.
  400: The minimum permissions for
  401: the mount point for traversal across the mount point in both
  402: directions to be possible for all users is 0111 (execute for all).
  403: .Sh HISTORY
  404: A
  405: .Nm
  406: utility appeared in
  407: .At v1 .