## SYNOPSIS

           mount [-lhV]

           mount -a [-fFnrsvw] [-t vfstype] [-O optlist]
           mount [-fnrsvw] [-o options [,...]] device | dir
           mount [-fnrsvw] [-t vfstype] [-o options] device dir

## DESCRIPTION

           All  files accessible in a Unix system are arranged in one
           big tree, the file hierarchy, rooted at  /.   These  files
           can  be spread out over several devices. The mount command
           serves to attach the file system found on some  device  to
           the  big file tree. Conversely, the umount(8) command will
           detach it again.

           The standard form of the mount command, is
                  mount -t type device dir
           This tells the kernel to attach the file system  found  on
           device  (which is of type type) at the directory dir.  The
           previous contents (if any)  and  owner  and  mode  of  dir
           become  invisible, and as long as this file system remains
           mounted, the pathname dir refers to the root of  the  file
           system on device.

           Three forms of invocation do not actually mount anything:
                  mount -h
           prints a help message;
                  mount -V
           prints a version string; and just
                  mount [-l] [-t type]
           lists all mounted file systems (of type type).  The option
           -l adds the (ext2, ext3 and XFS) labels in  this  listing.
           See below.

           Since  Linux  2.4.0  it is possible to remount part of the
           file hierarchy somewhere else. The call is
                  mount --bind olddir newdir
           After this call the same contents  is  accessible  in  two
           places.

           This call attaches only (part of) a single filesystem, not
           possible submounts. The entire  file  hierarchy  including
           submounts is attached a second place using
                  mount --rbind olddir newdir

           Since Linux 2.5.1 it is possible to atomically move a sub
           tree to another place. The call is
                  mount --move olddir newdir

           The proc file system is  not  associated  with  a  special
           device,  and  when mounting it, an arbitrary keyword, such
           as proc can be used instead  of  a  device  specification.
           (i) The command
                  mount -a [-t type] [-O optlist]
           (usually  given  in  a bootscript) causes all file systems
           mentioned in fstab (of the proper type  and/or  having  or
           not having the proper options) to be mounted as indicated,
           except for those whose line contains the  noauto  keyword.
           Adding  the  -F  option  will make mount fork, so that the
           filesystems are mounted simultaneously.

           (ii) When mounting a file system mentioned  in  fstab,  it
           suffices to give only the device, or only the mount point.

           (iii) Normally, only the superuser can mount file systems.
           However,  when  fstab  contains the user option on a line,
           then anybody can mount the corresponding system.

           Thus, given a line
                  /dev/cdrom  /cd  iso9660  ro,user,noauto,unhide
           any user can mount the iso9660 file system  found  on  his
           CDROM using the command
                  mount /dev/cdrom
           or
                  mount /cd
           For  more  details,  see  fstab(5).   Only  the  user that
           mounted a filesystem can unmount it again.   If  any  user
           should  be able to unmount, then use users instead of user
           in the fstab line.  The owner option  is  similar  to  the
           user  option,  with  the restriction that the user must be
           the owner of the special file. This may be useful e.g. for
           /dev/fd  if a login script makes the console user owner of
           this device.

           The programs mount and umount maintain a list of currently
           mounted  file  systems in the file /etc/mtab.  If no argu
           ments are given to mount, this list is printed.

           When the proc filesystem is mounted (say  at  /proc),  the
           files  /etc/mtab  and  /proc/mounts have very similar con
           tents. The former has somewhat more information,  such  as
           the  mount options used, but is not necessarily up-to-date
           (cf. the -n option  below).  It  is  possible  to  replace
           /etc/mtab  by  a  symbolic  link to /proc/mounts, but some
           information is lost that way, and  in  particular  working
           with  the  loop  device will be less convenient, and using
           the "user" option will fail.

## OPTIONS

           The full set of options used by an invocation of mount  is
           determined  by  first  extracting the options for the file
           system from the fstab table,  then  applying  any  options
           specified by the -o argument, and finally applying a -r or
                  incarnation of mount for each device.  This will do
                  the  mounts  on  different devices or different NFS
                  servers in parallel.  This has the  advantage  that
                  it  is  faster; also NFS timeouts go in parallel. A
                  disadvantage is that the mounts are done  in  unde
                  fined  order.   Thus, you cannot use this option if
                  you want to mount both /usr and /usr/spool.

           -f     Causes everything to be done except for the  actual
                  system  call;  if  it's not obvious, this ``fakes''
                  mounting the file system.  This option is useful in
                  conjunction  with the -v flag to determine what the
                  mount command is trying to do. It can also be  used
                  to  add  entries for devices that were mounted ear
                  lier with the -n option.

           -i     Don't call the /sbin/mount.<filesystem> helper even
                  if it exists.

           -l     Add the ext2, ext3 and XFS labels in the mount out
                  put. Mount must have permission to  read  the  disk
                  device  (e.g.  be suid root) for this to work.  One
                  can set such a label for ext2  or  ext3  using  the
                  e2label(8)  utility, or for XFS using xfs_admin(8).

           -n     Mount without writing in /etc/mtab.  This is neces
                  sary  for  example when /etc is on a read-only file
                  system.

           -s     Tolerate sloppy mount options rather than  failing.
                  This  will  ignore mount options not supported by a
                  filesystem type. Not all filesystems  support  this
                  option. This option exists for support of the Linux
                  autofs-based automounter.

           -r     Mount the file system read-only. A  synonym  is  -o
                  ro.

           -w     Mount  the  file  system  read/write.  This  is the
                  default. A synonym is -o rw.

           -L label
                  Mount the partition that has the specified label.

           -U uuid
                  Mount the partition that has  the  specified  uuid.
                  These two options require the file /proc/partitions
                  (present since Linux 2.1.116) to exist.

           -t vfstype
                  The argument following the -t is used  to  indicate
                  the  file system type.  The file system types which
                  required.  For  a  few  types  however  (like  nfs,
                  smbfs,  ncpfs) ad hoc code is necessary. The nfs ad
                  hoc code is built in, but smbfs and  ncpfs  have  a
                  separate  mount program. In order to make it possi
                  ble to treat all types in a uniform way, mount will
                  execute   the  program  /sbin/mount.TYPE  (if  that
                  exists) when called with type TYPE.  Since  various
                  versions  of  the  smbmount  program have different
                  calling conventions, /sbin/mount.smb may have to be
                  a shell script that sets up the desired call.

                  The  type  iso9660 is the default.  If no -t option
                  is given, or if the auto  type  is  specified,  the
                  superblock is probed for the filesystem type (adfs,
                  bfs, cramfs, ext, ext2, ext3, hfs,  hpfs,  iso9660,
                  jfs,  minix, ntfs, qnx4, reiserfs, romfs, udf, ufs,
                  vxfs, xfs, xiafs are  supported).   If  this  probe
                  fails,   mount   will   try   to   read   the  file
                  /etc/filesystems,  or,  if  that  does  not  exist,
                  /proc/filesystems.   All  of  the  filesystem types
                  listed there will be tried, except for  those  that
                  are  labeled  "nodev" (e.g., devpts, proc and nfs).
                  If /etc/filesystems ends in a line with a single  *
                  only, mount will read /proc/filesystems afterwards.

                  The auto type may be useful for user-mounted  flop
                  pies.  Creating a file /etc/filesystems can be use
                  ful to change the probe order (e.g.,  to  try  vfat
                  before  msdos)  or  if  you  use  a  kernel  module
                  autoloader.  Warning: the probing uses a  heuristic
                  (the  presence  of  appropriate `magic'), and could
                  recognize the wrong filesystem type, possibly  with
                  catastrophic  consequences.  If  your data is valu
                  able, don't ask mount to guess.

                  More than one type may be specified in a comma sep
                  arated  list.  The list of file system types can be
                  prefixed with no to specify the file  system  types
                  on  which  no action should be taken.  (This can be
                  meaningful with the -a option.)

                  For example, the command:
                         mount -a -t nomsdos,ext
                  mounts all file systems except those of type  msdos
                  and ext.

           -O     Used  in  conjunction  with -a, to limit the set of
                  filesystems to which the -a is applied.  Like -t in
                  this regard except that it is useless except in the
                  context of -a.  For example, the command:
                         mount -a -O no_netdev
                  mounts all file systems except those which have the

           -o     Options  are specified with a -o flag followed by a
                  comma separated string of options.  Some  of  these
                  options  are  only  useful  when they appear in the
                  /etc/fstab file.  The following  options  apply  to
                  any  file  system  that  is  being mounted (but not
                  every file system actually honors them - e.g.,  the
                  sync  option  today  has effect only for ext2, ext3
                  and ufs):

                  async  All I/O to the file system  should  be  done
                         asynchronously.

                  atime  Update  inode  access  time for each access.
                         This is the default.

                  auto   Can be mounted with the -a option.

                  defaults
                         Use default options: rw,  suid,  dev,  exec,
                         auto, nouser, and async.

                  dev    Interpret character or block special devices
                         on the file system.

                  exec   Permit execution of binaries.

                  _netdev
                         The filesystem  resides  on  a  device  that
                         requires network access (used to prevent the
                         system  from  attempting  to   mount   these
                         filesystems   until  the  network  has  been
                         enabled on the system).

                  noatime
                         Do not update inode  access  times  on  this
                         file  system  (e.g, for faster access on the
                         news spool to speed up news servers).

                  noauto Can only be mounted explicitly (i.e., the -a
                         option  will not cause the file system to be
                         mounted).

                  nodev  Do not interpret character or block  special
                         devices on the file system.

                  noexec Do  not  allow  execution of any binaries on
                         the mounted file system.  This option  might
                         be useful for a server that has file systems
                         containing binaries for architectures  other
                         than its own.

                  nosuid Do  not  allow  set-user-identifier  or set-
                  ro     Mount the file system read-only.

                  rw     Mount the file system read-write.

                  suid   Allow set-user-identifier or set-group-iden
                         tifier bits to take effect.

                  sync   All  I/O  to  the file system should be done
                         synchronously.

                  dirsync
                         All directory updates within the file system
                         should  be done synchronously.  This affects
                         the following  system  calls:  creat,  link,
                         unlink,  symlink,  mkdir,  rmdir,  mknod and
                         rename.

                  user   Allow an ordinary user  to  mount  the  file
                         system.   The  name  of the mounting user is
                         written to mtab so that he can  unmount  the
                         file  system again.  This option implies the
                         options noexec, nosuid,  and  nodev  (unless
                         overridden  by subsequent options, as in the
                         option line user,exec,dev,suid).

                  users  Allow every user to mount  and  unmount  the
                         file   system.    This  option  implies  the
                         options noexec, nosuid,  and  nodev  (unless
                         overridden  by subsequent options, as in the
                         option line users,exec,dev,suid).

           --bind Remount a subtree somewhere else (so that its  con
                  tents are available in both places). See above.

           --move Move a subtree to some other place. See above.

## FILESYSTEM SPECIFIC MOUNT OPTIONS

           The  following options apply only to certain file systems.
           We sort them by file system. They all follow the -o  flag.

## Mount options for adfs

           uid=value and gid=value
                  Set  the  owner  and group of the files in the file
                  system (default: uid=gid=0).

           ownmask=value and othmask=value
                  Set the permission mask for  ADFS  'owner'  permis
                  sions   and   'other'   permissions,   respectively
                  (default: 0700 and 0077, respectively).   See  also
                  /usr/src/linux/Documentation/filesystems/adfs.txt.

                  The value is given in octal.

           protect
                  Do not allow any changes to the protection bits  on
                  the file system.

           usemp  Set  uid  and gid of the root of the file system to
                  the uid and gid of the mount point upon  the  first
                  sync   or  umount,  and  then  clear  this  option.
                  Strange...

           verbose
                  Print an informational message for each  successful
                  mount.

           prefix=string
                  Prefix  used  before  volume name, when following a
                  link.

           volume=string
                  Prefix (of length at most 30) used before '/'  when
                  following a symbolic link.

           reserved=value
                  (Default:  2.) Number of unused blocks at the start
                  of the device.

           root=value
                  Give explicitly the location of the root block.

           bs=value
                  Give blocksize. Allowed values are 512, 1024, 2048,
                  4096.

           grpquota / noquota / quota / usrquota
                  These  options are accepted but ignored.  (However,
                  quota  utilities  may  react  to  such  strings  in
                  /etc/fstab.)

## Mount options for coherent

           None.

## Mount options for devpts

           The devpts file system is a pseudo file system, tradition
           ally mounted on /dev/pts.  In order to  acquire  a  pseudo
           terminal,  a  process  opens  /dev/ptmx; the number of the
           pseudo terminal is then made available to the process  and
           the   pseudo   terminal   slave   can   be   accessed   as
           /dev/pts/<number>.

## Mount options for ext

           None.  Note that the `ext' file system is obsolete.  Don't
           use  it.   Since  Linux  version 2.1.21 extfs is no longer
           part of the kernel source.

## Mount options for ext2

           The `ext2' file system is the standard Linux file  system.
           Due  to  a kernel bug, it may be mounted with random mount
           options (fixed in Linux 2.0.4).

           bsddf / minixdf
                  Set the behaviour for the statfs system  call.  The
                  minixdf  behaviour  is  to  return  in the f_blocks
                  field the total number of blocks of the  file  sys
                  tem,  while  the  bsddf  behaviour  (which  is  the
                  default) is to subtract the overhead blocks used by
                  the  ext2  file  system  and not available for file
                  storage. Thus

           % mount /k -o minixdf; df /k; umount /k
           Filesystem   1024-blocks  Used Available Capacity Mounted on
           /dev/sda6      2630655   86954  2412169      3%   /k
           % mount /k -o bsddf; df /k; umount /k
           Filesystem   1024-blocks  Used Available Capacity Mounted on
           /dev/sda6      2543714      13  2412169      0%   /k

           (Note that this example shows that  one  can  add  command
           line options to the options given in /etc/fstab.)

           check / check=normal / check=strict
                  Set  checking  level.  When  at  least one of these
                  options is set (and check=normal is set by default)
                  the  inodes  and  blocks  bitmaps  are checked upon
                  mount (which can take half a minute or so on a  big
                  disk,  and  is rather useless).  With strict check
                  ing, block deallocation checks that  the  block  to
                  free is in the data zone.

           check=none / nocheck
                  No  checking  is done. This is fast. Recent kernels
                  do not have a check option anymore - checking  with
                  e2fsck(8) is more meaningful.

           debug  Print debugging info upon each (re)mount.

           errors=continue / errors=remount-ro / errors=panic
                  Define  the behaviour when an error is encountered.
                  (Either ignore errors and just mark the file system
                  erroneous  and continue, or remount the file system

           resgid=n and resuid=n
                  The  ext2 file system reserves a certain percentage
                  of  the  available  space  (by  default   5%,   see
                  mke2fs(8) and tune2fs(8)).  These options determine
                  who can use the reserved blocks.  (Roughly: whoever
                  has  the specified uid, or belongs to the specified
                  group.)

           sb=n   Instead of block 1, use block n as superblock. This
                  could  be  useful when the filesystem has been dam
                  aged.  (Earlier, copies of the superblock would  be
                  made  every  8192  blocks: in block 1, 8193, 16385,
                  ... (and one got  hundreds  or  even  thousands  of
                  copies  on  a  big filesystem). Since version 1.08,
                  mke2fs has  a  -s  (sparse  superblock)  option  to
                  reduce  the number of backup superblocks, and since
                  version 1.15 this is the default.  Note  that  this
                  may  mean that ext2 filesystems created by a recent
                  mke2fs cannot be mounted r/w  under  Linux  2.0.*.)
                  The  block  number here uses 1k units. Thus, if you
                  want to use logical block  32768  on  a  filesystem
                  with 4k blocks, use "sb=131072".

           grpquota / noquota / quota / usrquota
                  These options are accepted but ignored.

           nouid32
                  Disables  32-bit UIDs and GIDs.  This is for inter
                  operability with older kernels which only store and
                  expect 16-bit values.

           user_xattr
                  Enable  Extended  User  Attributes. See the attr(5)
                  manual page.

           acl    Enable POSIX Access Control Lists. See  the  acl(5)
                  manual page.

## Mount options for ext3

           The  `ext3' file system is version of the ext2 file system
           which has been enhanced with journalling.  It supports the
           same options as ext2 as well as the following additions:

           journal=update
                  Update  the  ext3 file system's journal to the cur
                  rent format.

           journal=inum
                  When a  journal  already  exists,  this  option  is
                  ignored.  Otherwise, it specifies the number of the
                         to being written into the main file  system.

                  ordered
                         This  is  the  default  mode.   All  data is
                         forced directly out to the main file  system
                         prior to its metadata being committed to the
                         journal.

                  writeback
                         Data ordering is not preserved - data may be
                         written  into the main file system after its
                         metadata has been committed to the  journal.
                         This  is rumoured to be the highest-through
                         put option.   It  guarantees  internal  file
                         system  integrity,  however it can allow old
                         data to appear in files after  a  crash  and
                         journal recovery.

                  user_xattr
                         Enable  Extended  User  Attributes.  See the
                         attr(5) manual page.

                  acl    Enable POSIX Access Control Lists.  See  the
                         acl(5) manual page.

## Mount options for fat

           (Note: fat is not a separate filesystem, but a common part
           of the msdos, umsdos and vfat filesystems.)

           blocksize=512 / blocksize=1024 / blocksize=2048
                  Set blocksize (default 512).

           uid=value and gid=value
                  Set the owner and group of all files. (Default: the
                  uid and gid of the current process.)

           umask=value
                  Set  the umask (the bitmask of the permissions that
                  are not present). The default is the umask  of  the
                  current process.  The value is given in octal.

           dmask=value
                  Set  the  umask  applied  to directories only.  The
                  default is the umask of the current  process.   The
                  value is given in octal. Present since 2.5.43.

           fmask=value
                  Set  the  umask applied to regular files only.  The
                  default is the umask of the current  process.   The
                  value is given in octal. Present since 2.5.43.

                  s[trict]
                         Like  "normal",  but  names  may not contain
                         long parts and special characters  that  are
                         sometimes   used   on  Linux,  but  are  not
                         accepted by  MS-DOS  are  rejected.  (+,  =,
                         spaces, etc.)

           codepage=value
                  Sets the codepage for converting to shortname char
                  acters on FAT and  VFAT  filesystems.  By  default,
                  codepage 437 is used.

           conv=b[inary] / conv=t[ext] / conv=a[uto]
                  The  fat file system can perform CRLF<-->NL (MS-DOS
                  text format to UNIX text format) conversion in  the
                  kernel.  The  following conversion modes are avail
                  able:

                  binary no translation is performed.   This  is  the
                         default.

                  text   CRLF<-->NL  translation  is performed on all
                         files.

                  auto   CRLF<-->NL translation is performed  on  all
                         files  that don't have a "well-known binary"
                         extension. The list of known extensions  can
                         be  found  at the beginning of fs/fat/misc.c
                         (as of 2.0, the list is: exe, com, bin, app,
                         sys, drv, ovl, ovr, obj, lib, dll, pif, arc,
                         zip, lha, lzh, zoo, tar, z,  arj,  tz,  taz,
                         tzp,  tpz,  gz, tgz, deb, gif, bmp, tif, gl,
                         jpg, pcx, tfm, vf, gf, pk, pxl, dvi).

                  Programs that do computed lseeks won't like in-ker
                  nel text conversion.  Several people have had their
                  data ruined by this translation. Beware!

                  For file systems mounted in binary mode, a  conver
                  sion tool (fromdos/todos) is available.

           cvf_format=module
                  Forces the driver to use the CVF (Compressed Volume
                  File) module cvf_module instead of  auto-detection.
                  If  the  kernel  supports  kmod, the cvf_format=xxx
                  option also controls on-demand CVF module  loading.

           cvf_option=option
                  Option passed to the CVF module.

           debug  Turn  on  the  debug  flag.  A version string and a

           quiet  Turn on the quiet flag.  Attempts to chown or chmod
                  files do not return errors, although they fail. Use
                  with caution!

           sys_immutable, showexec, dots, nodots, dotsOK=[yes|no]
                  Various  misguided  attempts  to  force Unix or DOS
                  conventions onto a FAT file system.

## Mount options for hpfs

           uid=value and gid=value
                  Set the owner and group of all files. (Default: the
                  uid and gid of the current process.)

           umask=value
                  Set  the umask (the bitmask of the permissions that
                  are not present). The default is the umask  of  the
                  current process.  The value is given in octal.

           case=lower / case=asis
                  Convert  all  files  names  to lower case, or leave
                  them.  (Default: case=lower.)

           conv=binary / conv=text / conv=auto
                  For conv=text, delete some random CRs (in  particu
                  lar,  all followed by NL) when reading a file.  For
                  conv=auto, choose more or less  at  random  between
                  conv=binary  and  conv=text.  For conv=binary, just
                  read what is in the file. This is the default.

           nocheck
                  Do not  abort  mounting  when  certain  consistency
                  checks fail.

## Mount options for iso9660

           ISO  9660  is a standard describing a filesystem structure
           to be used on CD-ROMs. (This filesystem type is also  seen
           on some DVDs. See also the udf filesystem.)

           Normal  iso9660  filenames  appear  in a 8.3 format (i.e.,
           DOS-like restrictions on filename length), and in addition
           all  characters are in upper case.  Also there is no field
           for file ownership, protection, number of links, provision
           for block/character devices, etc.

           Rock Ridge is an extension to iso9660 that provides all of
           these unix like features.  Basically there are  extensions
           to each directory record that supply all of the additional
           information, and when Rock Ridge is in use, the filesystem
           is  indistinguishable  from  a  normal  UNIX  file  system

           uid=value and gid=value
                  Give  all  files  in  the file system the indicated
                  user or group id, possibly overriding the  informa
                  tion found in the Rock Ridge extensions.  (Default:
                  uid=0,gid=0.)

           map=n[ormal] / map=o[ff] / map=a[corn]
                  For non-Rock Ridge volumes, normal name translation
                  maps  upper  to  lower case ASCII, drops a trailing
                  `;1', and converts `;' to  `.'.   With  map=off  no
                  name  translation  is  done. See norock.  (Default:
                  map=normal.)  map=acorn is like map=normal but also
                  apply Acorn extensions if present.

           mode=value
                  For  non-Rock  Ridge  volumes,  give  all files the
                  indicated  mode.   (Default:  read  permission  for
                  everybody.)  Since Linux 2.1.37 one no longer needs
                  to specify the mode in decimal. (Octal is indicated
                  by a leading 0.)

           unhide Also show hidden and associated files.

           block=[512|1024|2048]
                  Set   the   block  size  to  the  indicated  value.
                  (Default: block=1024.)

           conv=a[uto] / conv=b[inary] / conv=m[text] / conv=t[ext]
                  (Default: conv=binary.)  Since  Linux  1.3.54  this
                  option has no effect anymore.  (And non-binary set
                  tings used to be very dangerous,  possibly  leading
                  to silent data corruption.)

           cruft  If  the high byte of the file length contains other
                  garbage, set this mount option to ignore  the  high
                  order bits of the file length.  This implies that a
                  file cannot  be  larger  than  16MB.   The  `cruft'
                  option is set automatically if the entire CDROM has
                  a weird size (negative, or more than 800MB). It  is
                  also  set when volume sequence numbers other than 0
                  or 1 are seen.

           session=x
                  Select number of session on multisession CD. (Since
                  2.3.4.)

           sbsector=xxx
                  Session begins from sector xxx. (Since 2.3.4.)

           The  following options are the same as for vfat and speci
           fying them only makes sense when using discs encoded using

           iocharset=name
                  Character set to use for converting from Unicode to
                  ASCII.  Joliet filenames are stored in Unicode for
                  mat, but Unix for the most part doesn't know how to
                  deal with Unicode.  There  is  also  an  option  of
                  doing UTF8 translations with the utf8 option.

           utf8   Encode Unicode names in UTF8 format. Default is no.

## Mount options for minix

           None.

## Mount options for msdos

           See mount options for  fat.   If  the  msdos  file  system
           detects an inconsistency, it reports an error and sets the
           file system read-only. The file system can be made  write
           able again by remounting it.

## Mount options for ncp

           Just  like  nfs,  the  ncp implementation expects a binary
           argument (a struct ncp_mount_data)  to  the  mount  system
           call.  This argument is constructed by ncpmount(8) and the
           current version of mount (2.6h)  does  not  know  anything
           about ncp.

## Mount options for nfs

           Instead  of a textual option string, parsed by the kernel,
           the nfs file system expects  a  binary  argument  of  type
           struct  nfs_mount_data.   The  program mount itself parses
           the following options of the form  `tag=value',  and  puts
           them   in   the  structure  mentioned:  rsize=n,  wsize=n,
           timeo=n, retrans=n,  acregmin=n,  acregmax=n,  acdirmin=n,
           acdirmax=n, actimeo=n, retry=n, port=n, mountport=n, moun
           thost=name,    mountprog=n,    mountvers=n,     nfsprog=n,
           nfsvers=n,  namlen=n.   The  option addr=n is accepted but
           ignored.  Also the  following  Boolean  options,  possibly
           preceded  by  no are recognized: bg, fg, soft, hard, intr,
           posix, cto, ac, tcp, udp, lock,  acl.   For  details,  see
           nfs(5).

           Especially useful options include

           rsize=8192,wsize=8192
                  This will make your nfs connection faster than with
                  the default buffer size of 4096.  (NFSv2  does  not
                  work with larger values of rsize and wsize.)

           nolock Do not use locking. Do not start lockd.

## Mount options for ntfs

           iocharset=name
                  Character set to use  when  returning  file  names.
                  Unlike  VFAT,  NTFS  suppresses  names that contain
                  unconvertible characters.

           utf8   Use UTF-8 for converting file names.

           uni_xlate=[0|1|2]
                  For 0 (or `no'  or  `false'),  do  not  use  escape
                  sequences  for  unknown  Unicode characters.  For 1
                  (or `yes' or `true') or 2,  use  vfat-style  4-byte
                  escape  sequences  starting with ":". Here 2 give a
                  little-endian encoding and 1 a  byteswapped  bigen
                  dian encoding.

           posix=[0|1]
                  If enabled (posix=1), the file system distinguishes
                  between upper and lower case. The 8.3  alias  names
                  are  presented  as hard links instead of being sup
                  pressed.

           uid=value, gid=value and umask=value
                  Set the file permission  on  the  filesystem.   The
                  umask  value  is  given  in octal.  By default, the
                  files are owned by root and not readable  by  some
                  body else.

## Mount options for proc

           uid=value and gid=value
                  These options are recognized, but have no effect as
                  far as I can see.

## Mount options for ramfs

           Ramfs is a memory based filesystem. Mount it and you  have
           it.  Unmount  it  and  it  is  gone.  Present  since Linux
           2.3.99pre4.  There are no mount options.

## Mount options for reiserfs

           Reiserfs is a journaling filesystem.  The  reiserfs  mount
           options      are      more      fully     described     at
           http://www.namesys.com/mount-options.html.

           conv   Instructs version 3.6 reiserfs software to mount  a
                  version  3.5  file system, using the 3.6 format for

                  tea    A Davis-Meyer function implemented by Jeremy
                         Fitzhardinge.  It uses hash  permuting  bits
                         in  the  name.  It gets high randomness and,
                         therefore, low probability  of  hash  colli
                         sions at come CPU cost.  This may be used if
                         EHASHCOLLISION errors are  experienced  with
                         the r5 hash.

                  r5     A  modified  version of the rupasov hash. It
                         is used by default and is  the  best  choice
                         unless  the file system has huge directories
                         and unusual file-name patterns.

                  detect Instructs mount to detect which  hash  func
                         tion  is in use by examining the file system
                         being mounted,  and to write  this  informa
                         tion  into  the reiserfs superblock. This is
                         only useful on the first  mount  of  an  old
                         format file system.

           hashed_relocation
                  Tunes the block allocator. This may provide perfor
                  mance improvements in some situations.

           no_unhashed_relocation
                  Tunes the block allocator. This may provide perfor
                  mance improvements in some situations.

           noborder
                  Disable  the border allocator algorithm invented by
                  Yury Yu. Rupasov.   This  may  provide  performance
                  improvements in some situations.

           nolog  Disable  journalling. This will provide slight per
                  formance improvements in  some  situations  at  the
                  cost   of  losing  reiserfs's  fast  recovery  from
                  crashes.  Even with this option turned on, reiserfs
                  still performs all journalling operations, save for
                  actual writes into its journalling area.  Implemen
                  tation of nolog is a work in progress.

           notail By  default,  reiserfs stores small files and `file
                  tails' directly into its tree. This  confuses  some
                  utilities  such as LILO(8).  This option is used to
                  disable packing of files into the tree.

           replayonly
                  Replay the transactions which are in  the  journal,
                  but  do  not actually mount the file system. Mainly
                  used by reiserfsck.

                  manual page.

## Mount options for romfs

           None.

## Mount options for smbfs

           Just like nfs, the smb  implementation  expects  a  binary
           argument  (a  struct  smb_mount_data)  to the mount system
           call. This argument is constructed by smbmount(8) and  the
           current  version  of  mount  (2.9w) does not know anything
           about smb.

## Mount options for sysv

           None.

## Mount options for tmpfs

           The following parameters accept a suffix k, m or g for Ki,
           Mi,  Gi (binary kilo, mega and giga) and can be changed on
           remount.

           size=nbytes
                  Override default size of the filesystem.  The  size
                  is  given  in  bytes,  and  rounded  down to entire
                  pages.  The default is half of the memory.

           nr_blocks=
                  Set number of blocks.

           nr_inodes=
                  Set number of inodes.

           mode=  Set initial permissions of the root directory.

## Mount options for udf

           udf is the "Universal Disk Format" filesystem  defined  by
           the  Optical  Storage Technology Association, and is often
           used for DVD-ROM.  See also iso9660.

           gid=   Set the default group.

           umask= Set the default  umask.   The  value  is  given  in
                  octal.

           uid=   Set the default user.

           unhide Show otherwise hidden files.

           session=
                  Set  the  CDROM  session  counting from 0. Default:
                  last session.

           anchor=
                  Override standard anchor location. Default: 256.

           volume=
                  Override the VolumeDesc location. (unused)

           partition=
                  Override the PartitionDesc location. (unused)

           lastblock=
                  Set the last block of the filesystem.

           fileset=
                  Override the fileset block location. (unused)

           rootdir=
                  Override the root directory location. (unused)

## Mount options for ufs

           ufstype=value
                  UFS is a file system widely used in different oper
                  ating  systems.   The problem are differences among
                  implementations. Features of  some  implementations
                  are undocumented, so its hard to recognize the type
                  of ufs automatically.  That's  why  the  user  must
                  specify  the type of ufs by mount option.  Possible
                  values are:

                  old    Old format of ufs, this is the default, read
                         only.  (Don't forget to give the -r option.)

                  44bsd  For filesystems created by a BSD-like system
                         (NetBSD,FreeBSD,OpenBSD).

                  sun    For  filesystems created by SunOS or Solaris
                         on Sparc.

                  sunx86 For filesystems created by Solaris on x86.

                  nextstep
                         For filesystems created by NeXTStep (on NeXT
                         station) (currently read only).

                  nextstep-cd
                         For  NextStep  CDROMs  (block_size == 2048),
                         read-only.

                         present; when an error is encountered only a
                         console message is printed.

## Mount options for umsdos

           See mount options for msdos.  The dotsOK option is explic
           itly killed by umsdos.

## Mount options for vfat

           First of all, the mount options for  fat  are  recognized.
           The  dotsOK option is explicitly killed by vfat.  Further
           more, there are

           uni_xlate
                  Translate unhandled Unicode characters  to  special
                  escaped   sequences.   This  lets  you  backup  and
                  restore filenames that are created with any Unicode
                  characters. Without this option, a '?' is used when
                  no translation is possible. The escape character is
                  ':'  because  it  is  otherwise illegal on the vfat
                  filesystem. The escape  sequence  that  gets  used,
                  where  u  is  the  unicode character, is: ':', (u &
                  0x3f), ((u>>6) & 0x3f), (u>>12).

           posix  Allow two files with  names  that  only  differ  in
                  case.

           nonumtail
                  First  try  to  make  a short name without sequence
                  number, before trying name~num.ext.

           utf8   UTF8 is the filesystem safe 8-bit encoding of  Uni
                  code  that  is  used  by  the console. It can be be
                  enabled for the filesystem with  this  option.   If
                  `uni_xlate' gets set, UTF8 gets disabled.

           shortname=[lower|win95|winnt|mixed]

                  Defines  the  behaviour for creation and display of
                  filenames which fit into 8.3 characters. If a  long
                  name for a file exists, it will always be preferred
                  display. There are four modes:

                  lower  Force the short name to lower case upon dis
                         play;  store a long name when the short name
                         is not all upper case.

                  win95  Force the short name to upper case upon dis
                         play;  store a long name when the short name
                         is not all upper case.

## Mount options for xfs

           biosize=size
                  Sets the preferred buffered I/O size (default  size
                  is  64K).   size must be expressed as the logarithm
                  (base2) of the desired I/O size.  Valid values  for
                  this option are 14 through 16, inclusive (i.e. 16K,
                  32K, and 64K bytes).  On machines with a  4K  page
                  size, 13 (8K bytes) is also a valid size.  The pre
                  ferred buffered I/O size can also be altered on  an
                  individual  file  basis  using  the ioctl(2) system
                  call.

           dmapi  /  xdsm
                  Enable the DMAPI (Data Management API) event  call
                  outs.

           logbufs=value
                  Set  the  number  of  in-memory log buffers.  Valid
                  numbers range  from  2-8  inclusive.   The  default
                  value is 8 buffers for filesystems with a blocksize
                  of 64K, 4 buffers for filesystems with a  blocksize
                  of  32K, 3 buffers for filesystems with a blocksize
                  of 16K, and 2 buffers for all other configurations.
                  Increasing  the number of buffers may increase per
                  formance on some workloads at the cost of the  mem
                  ory  used  for the additional log buffers and their
                  associated control structures.

           logbsize=value
                  Set the size of each in-memory log  buffer.   Valid
                  sizes are 16384 (16K) and 32768 (32K).  The default
                  value for machines with more than 32MB of memory is
                  32768,  machines  with  less  memory  use  16384 by
                  default.

           logdev=device and rtdev=device
                  Use an external log (metadata journal) and/or real-
                  time  device.   An  XFS  filesystem has up to three
                  parts: a data section, a log section, and  a  real-
                  time  section.   The real-time section is optional,
                  and the log section can be separate from  the  data
                  section or contained within it.  Refer to xfs(5).

           noalign
                  Data allocations will not be aligned at stripe unit
                  boundaries.

           noatime
                  Access timestamps are not updated when  a  file  is
                  read.

                  option  is in effect, timestamp updates from O_SYNC
                  writes can be lost if the system crashes.

           quota / usrquota / uqnoenforce
                  User disk  quota  accounting  enabled,  and  limits
                  (optionally) enforced.

           grpquota / gqnoenforce
                  Group  disk  quota  accounting  enabled  and limits
                  (optionally) enforced.

           sunit=value and swidth=value
                  Used to specify the stripe unit  and  width  for  a
                  RAID  device  or  a  stripe  volume.  value must be
                  specified in 512-byte block units.  If this  option
                  is  not  specified and the filesystem was made on a
                  stripe volume or the  stripe  width  or  unit  were
                  specified  for  the  RAID device at mkfs time, then
                  the mount system call will restore the  value  from
                  the  superblock.   For  filesystems  that  are made
                  directly on RAID devices, these options can be used
                  to  override  the  information in the superblock if
                  the  underlying  disk  layout  changes  after   the
                  filesystem  has been created.  The swidth option is
                  required if the sunit option  has  been  specified,
                  and must be a multiple of the sunit value.

## Mount options for xiafs

           None. Although nothing is wrong with xiafs, it is not used
           much, and is not maintained. Probably  one  shouldn't  use
           it.  Since Linux version 2.1.21 xiafs is no longer part of
           the kernel source.

## THE LOOP DEVICE

           One further possible type is a mount via the loop  device.
           For example, the command

             mount /tmp/fdimage /mnt -t msdos -o loop=/dev/loop3,blocksize=1024

           will  set  up  the loop device /dev/loop3 to correspond to
           the file /tmp/fdimage, and then mount this device on /mnt.
           This type of mount knows about three options, namely loop,
           offset and encryption, that are  really  options  to  los
           etup(8).   If  no  explicit  loop device is mentioned (but
           just an option `-o loop' is given), then mount will try to
           find some unused loop device and use that.  If you are not
           so  unwise  as  to  make  /etc/mtab  a  symbolic  link  to
           /proc/mounts  then any loop device allocated by mount will
           be freed by umount.  You can also free a  loop  device  by
           hand, using `losetup -d', see losetup(8).

           8      user interrupt

           16     problems writing or locking /etc/mtab

           32     mount failure

           64     some mount succeeded

## FILES

           /etc/fstab file system table
           /etc/mtab table of mounted file systems
           /etc/mtab~ lock file
           /etc/mtab.tmp temporary file

## SEE ALSO

           mount(2),   umount(2),   fstab(5),  umount(8),  swapon(8),
           nfs(5),  xfs(5),  e2label(8),   xfs_admin(8),   mountd(8),
           nfsd(8), mke2fs(8), tune2fs(8), losetup(8)

## BUGS

           It  is  possible  for  a  corrupted file system to cause a
           crash.

           Some Linux file systems  don't  support  -o  sync  and  -o
           dirsync  (the  ext2  and ext3 file systems do support syn
           chronous updates (a la BSD) when  mounted  with  the  sync
           option).

           The  -o remount may not be able to change mount parameters
           (all ext2fs-specific parameters, except sb, are changeable
           with  a  remount, for example, but you can't change gid or
           umask for the fatfs).

## HISTORY

           A mount command existed in Version 5 AT&T UNIX.

    Linux 2.0               14 September 1997                MOUNT(8)