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MOUNT(8)                   Linux Programmer's Manual                  MOUNT(8)



NAME
       mount(2,8) - mount(2,8) a file(1,n) system

SYNOPSIS
       mount(2,8) [-lhV]

       mount(2,8) -a [-fFnrsvw] [-t vfstype] [-O optlist]
       mount(2,8) [-fnrsvw] [-o options [,...]] device | dir
       mount(2,8) [-fnrsvw] [-t vfstype] [-o options] device dir

DESCRIPTION
       All files accessible in(1,8) a Unix system are arranged in(1,8) one big tree, the
       file(1,n) hierarchy, rooted at /.  These files can be spread out  over  sev-
       eral  devices. The mount(2,8) command serves to attach the file(1,n) system found
       on some device to the big file(1,n) tree. Conversely, the umount(8)  command
       will detach it again.

       The standard form of the mount(2,8) command, is
              mount(2,8) -t type device dir
       This  tells the kernel to attach the file(1,n) system found on device (which
       is of type type) at the directory dir.  The previous contents (if(3,n)  any)
       and  owner  and  mode of dir become invisible, and as long as this file(1,n)
       system remains mounted, the pathname dir refers to the root of the file(1,n)
       system on device.

       Three forms of invocation do not actually mount(2,8) anything:
              mount(2,8) -h
       prints a help message;
              mount(2,8) -V
       prints a version(1,3,5) string(3,n); and just
              mount(2,8) [-l] [-t type]
       lists  all mounted file(1,n) systems (of type type).  The option -l adds the
       (ext2, ext3 and XFS) labels in(1,8) this listing.  See below.

       Since Linux 2.4.0 it is possible to remount part of the file(1,n)  hierarchy
       somewhere else. The call is
              mount(2,8) --bind olddir newdir
       After this call the same contents is accessible in(1,8) two places.  One can
       also remount a single file(1,n) (on a single file(1,n)).

       This call attaches only (part of) a  single  filesystem,  not  possible
       submounts.  The entire file(1,n) hierarchy including submounts is attached a
       second place using
              mount(2,8) --rbind olddir newdir

       Note that the filesystem mount(2,8) options will remain the same as those on
       the  original  mount(2,8)  point,  and  cannot  be changed by passing the -o
       option along with --bind/--rbind.

       Since Linux 2.5.1 it is possible to atomically move(3x,7,3x curs_move) a mounted  tree  to
       another place. The call is
              mount(2,8) --move olddir newdir

       The  proc(5,n) file(1,n) system is not associated with a special device, and when
       mounting it, an arbitrary keyword, such as proc(5,n) can be used instead  of
       a  device specification.  (The customary choice none is less(1,3) fortunate:
       the error(8,n) message `none busy' from umount can be confusing.)

       Most devices are indicated by a file(1,n) name (of a block special  device),
       like  /dev/sda1, but there are other possibilities. For example, in(1,8) the
       case of an NFS mount(2,8), device may look(1,8,3 Search::Dict) like  knuth.cwi.nl:/dir.   It  is
       possible  to  indicate a block special device using its volume label or
       UUID (see the -L and -U options below).

       The file(1,n) /etc/fstab (see fstab(5)), may contain lines  describing  what
       devices  are  usually  mounted where, using which options. This file(1,n) is
       used in(1,8) three ways:

       (i) The command
              mount(2,8) -a [-t type] [-O optlist]
       (usually given in(1,8) a bootscript) causes all file(1,n)  systems  mentioned  in(1,8)
       fstab  (of  the  proper  type  and/or  having  or not having the proper
       options) to be mounted as indicated, except for those whose  line  con-
       tains the noauto keyword. Adding the -F option will make mount(2,8) fork, so
       that the filesystems are mounted simultaneously.

       (ii) When mounting a file(1,n) system mentioned in(1,8)  fstab,  it  suffices  to
       give only the device, or only the mount(2,8) point.

       (iii)  Normally,  only  the superuser can mount(2,8) file(1,n) systems.  However,
       when fstab contains the user option on a line, anybody  can  mount(2,8)  the
       corresponding system.

       Thus, given a line
              /dev/cdrom  /cd  iso9660  ro,user,noauto,unhide
       any user can mount(2,8) the iso9660 file(1,n) system found on his CDROM using the
       command
              mount(2,8) /dev/cdrom
       or
              mount(2,8) /cd
       For more details, see fstab(5).  Only the user that mounted a  filesys-
       tem  can unmount it again.  If any user should be able to unmount, then
       use users(1,5) instead of user in(1,8) the fstab line.  The owner option is simi-
       lar  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(3,n)  a
       login(1,3,5)  script  makes  the console(4,n) user owner of this device.  The group
       option is similar, with the restriction that the user must be member of
       the group of the special file.

       The programs mount(2,8) and umount maintain a list of currently mounted file(1,n)
       systems in(1,8) the file(1,n) /etc/mtab.  If no arguments  are  given  to  mount(2,8),
       this list is printed.

       When the proc(5,n) filesystem is mounted (say at /proc(5,n)), the files /etc/mtab
       and /proc(5,n)/mounts have very similar contents. The  former  has  somewhat
       more  information, such as the mount(2,8) options used, but is not necessar-
       ily up-to-date (cf. the -n option below). It  is  possible  to  replace
       /etc/mtab  by  a symbolic link(1,2) to /proc(5,n)/mounts, and especially when you
       have very large numbers of mounts things will be much faster with  that
       symlink, but some information is lost that way, and in(1,8) particular work-
       ing with the loop device will be less(1,3) convenient, and using the  "user"
       option will fail.


OPTIONS
       The full set(7,n,1 builtins) of options used by an invocation of mount(2,8) is determined by
       first extracting the options for the file(1,n) system from the fstab  table,
       then  applying  any  options  specified by the -o argument, and finally
       applying a -r or -w option, when present.

       Options available for the mount(2,8) command:

       -V     Output version.

       -h     Print a help message.

       -v     Verbose mode.

       -a     Mount all filesystems (of the given types) mentioned in(1,8) fstab.

       -F     (Used in(1,8) conjunction with -a.)  Fork off a  new  incarnation  of
              mount(2,8)  for  each  device.   This will do the mounts on different
              devices or different NFS servers  in(1,8)  parallel.   This  has  the
              advantage that it is faster; also NFS timeouts go in(1,8) parallel. A
              disadvantage is that the mounts are  done  in(1,8)  undefined  order.
              Thus,  you cannot use this option if(3,n) you want to mount(2,8) both /usr
              and /usr/spool.

       -f     Causes everything to be done except for the actual system  call;
              if(3,n)  it's  not  obvious, this ``fakes'' mounting the file(1,n) system.
              This option is useful in(1,8) conjunction with the -v flag to  deter-
              mine what the mount(2,8) command is trying to do. It can also be used
              to add entries for devices that were mounted earlier with the -n
              option.

       -i     Don't  call  the  /sbin/mount.<filesystem>  helper  even  if(3,n)  it
              exists.

       -l     Add the ext2, ext3 and XFS labels in(1,8)  the  mount(2,8)  output.  Mount
              must have permission to read(2,n,1 builtins) the disk device (e.g. be suid root)
              for this to work.  One can set(7,n,1 builtins) such a label  for  ext2  or  ext3
              using  the e2label(8) utility, or for XFS using xfs_admin(8), or
              for reiserfs using reiserfstune(8).

       -n     Mount without writing in(1,8) /etc/mtab.  This is necessary for exam-
              ple when /etc is on a read-only file(1,n) system.

       -p num In  case  of  a  loop mount(2,8) with encryption, read(2,n,1 builtins) the passphrase
              from file(1,n) descriptor num instead of from the terminal.

       -s     Tolerate sloppy mount(2,8) options rather  than  failing.  This  will
              ignore mount(2,8) 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(1,n) system read-only. A synonym is -o ro.

       -w     Mount the file(1,n) system read(2,n,1 builtins)/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(1,n) /proc(5,n)/partitions (present since Linux
              2.1.116) to exist.

       -t vfstype
              The argument following the -t is used to indicate the file(1,n)  sys-
              tem  type.   The file(1,n) system types which are currently supported
              include: adfs, affs, autofs,  coda,  coherent,  cramfs,  devpts,
              efs,  ext,  ext2,  ext3,  hfs, hpfs, iso9660, jfs, minix, msdos,
              ncpfs, nfs, ntfs, proc(5,n), qnx4,  ramfs,  reiserfs,  romfs,  smbfs,
              sysv,  tmpfs,  udf, ufs, umsdos, usbfs, vfat, xenix, xfs, xiafs.
              Note that coherent, sysv and xenix are equivalent and that xenix
              and  coherent will be removed at some point in(1,8) the future -- use
              sysv instead. Since kernel version(1,3,5)  2.1.21  the  types  ext  and
              xiafs  do  not exist anymore. Earlier, usbfs was known as usbde-
              vfs.

              For most types all the mount(2,8) program has to do is issue a simple
              mount(2,8)(2)  system call, and no detailed knowledge of the filesys-
              tem type is required.  For a few types however (like nfs, smbfs,
              ncpfs)  ad  hoc  code is necessary. The nfs ad hoc code is built
              in(1,8), but smbfs and ncpfs have a separate mount(2,8) program. In  order
              to  make  it possible to treat all types in(1,8) a uniform way, mount(2,8)
              will execute the program /sbin/mount.TYPE (if(3,n) that exists)  when
              called  with  type TYPE.  Since various versions of the smbmount
              program have different  calling  conventions,  /sbin/mount.smbfs
              may have to be a shell script that sets up the desired call.

              If  no  -t  option  is  given, or if(3,n) the auto(5,8) type is specified,
              mount(2,8) will try to guess the desired type.  If mount(2,8) was compiled
              with  the  blkid  library, the guessing is done by this library.
              Otherwise, mount(2,8) guesses itself by probing  the  superblock;  if(3,n)
              that  does  not turn up anything that looks familiar, mount(2,8) will
              try to read(2,n,1 builtins) the file(1,n) /etc/filesystems,  or,  if(3,n)  that  does  not
              exist,  /proc(5,n)/filesystems.   All  of the filesystem types listed
              there will be tried, except for those that are  labeled  "nodev"
              (e.g.,  devpts,  proc(5,n)  and  nfs).  If /etc/filesystems ends in(1,8) a
              line with a single * only,  mount(2,8)  will  read(2,n,1 builtins)  /proc(5,n)/filesystems
              afterwards.

              The auto(5,8) type may be useful for user-mounted floppies.  Creating
              a file(1,n) /etc/filesystems can be useful to change the probe  order
              (e.g.,  to  try vfat before msdos or ext3 before ext2) or if(3,n) you
              use a kernel module autoloader.  Warning:  the  probing  uses  a
              heuristic  (the presence of appropriate `magic(4,5)'), and could rec-
              ognize the wrong filesystem  type,  possibly  with  catastrophic
              consequences.  If  your  data  is  valuable,  don't ask mount(2,8) to
              guess.

              More than one type may be specified in(1,8) a comma  separated  list.
              The list of file(1,n) system types can be prefixed with no to specify
              the file(1,n) system types on which no action should be taken.  (This
              can be meaningful with the -a option.)

              For example, the command:
                     mount(2,8) -a -t nomsdos,ext
              mounts all file(1,n) systems except those of type msdos and ext.

       -O     Used  in(1,8) conjunction with -a, to limit the set(7,n,1 builtins) of filesystems to
              which the -a is applied.  Like -t in(1,8) this regard except that  it
              is  useless  except in(1,8) the context of -a.  For example, the com-
              mand:
                     mount(2,8) -a -O no_netdev
              mounts all file(1,n) systems except those which have the option _net-
              dev specified in(1,8) the options field in(1,8) the /etc/fstab file.

              It  is different from -t in(1,8) that each option is matched exactly;
              a leading no at the beginning of one option does not negate  the
              rest.

              The  -t  and  -O  options are cumulative in(1,8) effect; that is, the
              command
                     mount(2,8) -a -t ext2 -O _netdev
              mounts all ext2 filesystems with the  _netdev  option,  not  all
              filesystems  that  are  either  ext2  or have the _netdev option
              specified.

       -o     Options are specified with a -o flag followed by a  comma  sepa-
              rated  string(3,n) of options.  Some of these options are only useful
              when they appear in(1,8) the /etc/fstab file.  The following  options
              apply  to  any  file(1,n) system that is being mounted (but not every
              file(1,n) system actually honors them - e.g., the sync(1,2,8)  option  today
              has effect only for ext2, ext3 and ufs):

              async  All I/O to the file(1,n) system should be done asynchronously.

              atime  Update inode access(2,5) time(1,2,n) for each  access.  This  is  the
                     default.

              auto(5,8)   Can be mounted with the -a option.

              defaults
                     Use  default  options: rw, suid, dev, exec(3,n,1 builtins), auto(5,8), nouser,
                     and async.

              dev    Interpret character or block special devices on the  file(1,n)
                     system.

              exec(3,n,1 builtins)   Permit execution of binaries.

              group  Allow an ordinary (i.e., non-root) user to mount(2,8) the file(1,n)
                     system if(3,n) one of his groups  matches  the  group  of  the
                     device.  This option implies the options nosuid and nodev
                     (unless overridden  by  subsequent  options,  as  in(1,8)  the
                     option line group,dev,suid).

              mand   Allow mandatory locks on this filesystem. See fcntl(2).

              _netdev
                     The  filesystem resides on a device that requires network
                     access(2,5) (used to prevent the  system  from  attempting  to
                     mount(2,8)  these  filesystems  until  the  network  has  been
                     enabled on the system).

              noatime
                     Do not update(7,n) inode access(2,5)  times  on  this  file(1,n)  system
                     (e.g,  for  faster  access(2,5)  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(1,n) system to be mounted).

              nodev  Do  not  interpret  character or block special devices on
                     the file(1,n) system.

              noexec Do not allow direct execution  of  any  binaries  on  the
                     mounted  file(1,n) system.  (Until recently it was possible to
                     run binaries anyway  using  a  command  like  /lib/ld(1,8)*.so
                     /mnt/binary.  This  trick  fails  since  Linux  2.4.25  /
                     2.6.0.)

              nomand Do not allow mandatory locks on this filesystem.

              nosuid Do not allow set-user-identifier or  set-group-identifier
                     bits  to  take  effect.  (This seems safe, but is in(1,8) fact
                     rather unsafe if(3,n) you have suidperl(1) installed.)

              nouser Forbid an ordinary (i.e., non-root)  user  to  mount(2,8)  the
                     file(1,n) system.  This is the default.

              owner  Allow an ordinary (i.e., non-root) user to mount(2,8) the file(1,n)
                     system if(3,n) he is the owner of  the  device.   This  option
                     implies  the  options nosuid and nodev (unless overridden
                     by  subsequent   options,   as   in(1,8)   the   option   line
                     owner,dev,suid).

              remount
                     Attempt  to remount an already-mounted file(1,n) system.  This
                     is commonly used to change the mount(2,8)  flags  for  a  file(1,n)
                     system,  especially to make a readonly file(1,n) system write-
                     able. It does not change device or mount(2,8) point.

              ro     Mount the file(1,n) system read-only.

              rw     Mount the file(1,n) system read-write.

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

              sync(1,2,8)   All  I/O to the file(1,n) system should be done synchronously.

              dirsync
                     All directory updates within the file(1,n)  system  should  be
                     done  synchronously.   This  affects the following system
                     calls: creat, link(1,2), unlink(1,2), symlink, mkdir(1,2), rmdir(1,2),  mknod(1,2)
                     and rename.

              user   Allow  an  ordinary  user  to mount(2,8) the file(1,n) system.  The
                     name of the mounting user is written to mtab so  that  he
                     can  unmount  the file(1,n) system again.  This option implies
                     the options noexec, nosuid, and nodev (unless  overridden
                     by   subsequent   options,   as   in(1,8)   the   option  line
                     user,exec(3,n,1 builtins),dev,suid).

              users(1,5)  Allow every user to mount(2,8) and unmount  the  file(1,n)  system.
                     This option implies the options noexec, nosuid, and nodev
                     (unless overridden  by  subsequent  options,  as  in(1,8)  the
                     option line users(1,5),exec(3,n,1 builtins),dev,suid).

       --bind Remount  a  subtree  somewhere  else  (so  that its contents are
              available in(1,8) 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(1,n) systems.  We sort(1,3) them
       by file(1,n) system. They all follow the -o flag.

       What  options  are supported depends a bit on the running kernel.  More
       info(1,5,n)  may  be  found  in(1,8)  the  kernel  source  subdirectory  Documenta-
       tion/filesystems.


Mount options for adfs
       uid=value and gid=value
              Set  the  owner  and  group  of  the  files  in(1,8)  the file(1,n) system
              (default: uid=gid=0).

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

Mount options for affs
       uid=value and gid=value
              Set the owner and group of the root of the file(1,n) system (default:
              uid=gid=0, but with option uid or gid without  specified  value,
              the uid and gid of the current process are taken).

       setuid=value and setgid=value
              Set the owner and group of all files.

       mode=value
              Set the mode of all files to value & 0777 disregarding the orig-
              inal permissions.  Add search  permission  to  directories  that
              have read(2,n,1 builtins) permission.  The value is given in(1,8) octal.

       protect
              Do not allow any changes to the protection bits on the file(1,n) sys-
              tem.

       usemp  Set uid and gid of the root of the file(1,n) system to  the  uid  and
              gid  of  the mount(2,8) point upon the first sync(1,2,8) or umount, and then
              clear(1,3x,3x clrtobot) this option. Strange...

       verbose
              Print an informational message for each successful mount.

       prefix=string(3,n)
              Prefix used before volume name, when following a link.

       volume=string(3,n)
              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(1,8) / usrquota
              These options are accepted but ignored.  (However, quota(1,8)  utili-
              ties may react to such strings in(1,8) /etc/fstab.)


Mount options for coherent
       None.


Mount options for devpts
       The  devpts  file(1,n) system is a pseudo file(1,n) system, traditionally 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>.

       uid=value and gid=value
              This  sets  the  owner or the group of newly created PTYs to the
              specified values. When nothing is specified, they will be set(7,n,1 builtins) to
              the  UID and GID of the creating process.  For example, if(3,n) there
              is a tty(1,4) group with GID 5, then gid=5 will cause  newly  created
              PTYs to belong to the tty(1,4) group.

       mode=value
              Set  the mode of newly created PTYs to the specified value.  The
              default is 0600.  A value of mode=620 and gid=5 makes  "mesg  y"
              the default on newly created PTYs.


Mount options for ext
       None.   Note  that  the  `ext'  file(1,n)  system is obsolete. Don't use it.
       Since Linux version(1,3,5) 2.1.21 extfs  is  no  longer  part  of  the  kernel
       source.


Mount options for ext2
       The  `ext2' file(1,n) system is the standard Linux file(1,n) system.  Since Linux
       2.5.46, for most  mount(2,8)  options  the  default  is  determined  by  the
       filesystem superblock. Set them with tune2fs(8).

       acl / noacl
              Support POSIX Access Control Lists (or not).

       bsddf / minixdf
              Set the behaviour for the statfs system call. The minixdf behav-
              iour is to return in(1,8) the f_blocks  field  the  total  number  of
              blocks  of  the file(1,n) system, while the bsddf behaviour (which is
              the default) is to subtract the overhead blocks used by the ext2
              file(1,n) system and not available for file(1,n) storage. Thus

       % mount(2,8) /k -o minixdf; df /k; umount /k
       Filesystem   1024-blocks  Used Available Capacity Mounted on
       /dev/sda6      2630655   86954  2412169      3%   /k
       % mount(2,8) /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(1,8) /etc/fstab.)


       check  Check filesystem (block and inode bitmaps) at mount(2,8) time.

       check=none / nocheck
              No checking is done at mount(2,8) time. This is the default. This  is
              fast.   It  is wise to invoke e2fsck(8) every now and then, e.g.
              at boot time.

       debug  Print debugging info(1,5,n) upon each (re)mount.

       errors=continue / errors=remount-ro / errors=panic
              Define the behaviour when  an  error(8,n)  is  encountered.   (Either
              ignore  errors  and just mark the file(1,n) system erroneous and con-
              tinue, or remount the file(1,n) system read-only, or panic  and  halt
              the  system.)   The default is set(7,n,1 builtins) in(1,8) the filesystem superblock,
              and can be changed using tune2fs(8).

       grpid or bsdgroups / nogrpid or sysvgroups
              These options define what group id a newly  created  file(1,n)  gets.
              When  grpid  is  set(7,n,1 builtins),  it takes the group id of the directory in(1,8)
              which it is created; otherwise (the default) it takes the  fsgid
              of  the current process, unless the directory has the setgid bit
              set(7,n,1 builtins), in(1,8) which case it takes the gid from the  parent  directory,
              and also gets(3,n) the setgid bit set(7,n,1 builtins) if(3,n) it is a directory itself.

       grpquota / noquota / quota(1,8) / usrquota
              These options are accepted but ignored.

       nobh   Do not attach buffer_heads to file(1,n) pagecache. (Since 2.5.49.)

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

       oldalloc or orlov
              Use old allocator or Orlov allocator for new  inodes.  Orlov  is
              default.

       resgid=n and resuid=n
              The ext2 file(1,n) system reserves a certain percentage of the avail-
              able 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 damaged.   (Earlier,  copies
              of  the  superblock would be made every 8192 blocks: in(1,8) block 1,
              8193, 16385, ... (and one got  thousands  of  copies  on  a  big
              filesystem).  Since  version(1,3,5)  1.08,  mke2fs  has  a  -s  (sparse
              superblock) option to reduce the number of  backup  superblocks,
              and  since  version(1,3,5) 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(3,n) you  want  to  use  logical  block  32768  on  a
              filesystem with 4k blocks, use "sb=131072".

       user_xattr / nouser_xattr
              Support "user." extended attributes (or not).



Mount options for ext3
       The  `ext3'  file(1,n) system is a version(1,3,5) of the ext2 file(1,n) system which has
       been enhanced with journalling.  It supports the same options  as  ext2
       as well as the following additions:

       journal=update(7,n)
              Update the ext3 file(1,n) system's journal to the current format.

       journal=inum
              When  a  journal  already exists, this option is ignored. Other-
              wise, it specifies the number of the inode which will  represent
              the  ext3  file(1,n)  system's  journal file(1,n);  ext3 will create a new
              journal, overwriting the old contents of the  file(1,n)  whose  inode
              number is inum.

       noload Do not load(7,n) the ext3 file(1,n) system's journal on mounting.

       data=journal / data=ordered / data=writeback
              Specifies  the  journalling  mode  for  file(1,n)  data.  Metadata is
              always journaled.  To use modes other than ordered on  the  root
              file(1,n) system, pass the mode to the kernel as boot parameter, e.g.
              rootflags=data=journal.

              journal
                     All data is committed into the  journal  prior  to  being
                     written into the main file(1,n) system.

              ordered
                     This  is  the  default mode.  All data is forced directly
                     out to the main file(1,n) system prior to its  metadata  being
                     committed to the journal.

              writeback
                     Data ordering is not preserved - data may be written into
                     the main file(1,n) system after its metadata has been  commit-
                     ted  to the journal.  This is rumoured to be the highest-
                     throughput option.  It guarantees  internal  file(1,n)  system
                     integrity,  however  it  can  allow old data to appear in(1,8)
                     files after a crash and journal recovery.

       commit=nrsec
              Sync all data and metadata  every  nrsec  seconds.  The  default
              value is 5 seconds. Zero means default.


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(1,8) octal.

       dmask=value
              Set  the  umask applied to directories only.  The default is the
              umask of the current process.  The value is given in(1,8) octal.

       fmask=value
              Set the umask applied to regular files only.  The default is the
              umask of the current process.  The value is given in(1,8) octal.

       check=value
              Three different levels of pickyness can be chosen:

              r[elaxed]
                     Upper  and  lower  case are accepted and equivalent, long
                     name  parts  are  truncated  (e.g.    verylongname.foobar
                     becomes  verylong.foo),  leading  and embedded spaces are
                     accepted in(1,8) each name part (name and extension).

              n[ormal]
                     Like "relaxed", but many special  characters  (*,  ?,  <,
                     spaces, etc.) are rejected.  This is the default.

              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 characters on  FAT
              and VFAT filesystems. By default, codepage 437 is used.

       conv=b[inary] / conv=t[ext] / conv=a[uto]
              The  fat  file(1,n) system can perform CRLF<-->NL (MS-DOS text format
              to UNIX text format) conversion in(1,8)  the  kernel.  The  following
              conversion modes are available:

              binary no translation is performed.  This is the default.

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

              auto(5,8)   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(1,n), 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-kernel text  con-
              version.   Several  people  have  had  their data ruined by this
              translation. Beware!

              For file(1,n) systems mounted  in(1,8)  binary  mode,  a  conversion  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 mod-
              ule loading.

       cvf_option=option
              Option passed to the CVF module.

       debug  Turn on the debug flag.  A version(1,3,5) string(3,n) and  a  list  of  file(1,n)
              system  parameters  will be printed (these data are also printed
              if(3,n) the parameters appear to be inconsistent).

       fat=12 / fat=16 / fat=32
              Specify a 12, 16 or 32 bit fat.  This  overrides  the  automatic
              FAT type detection routine.  Use with caution!

       iocharset=value
              Character set(7,n,1 builtins) to use for converting between 8 bit characters and
              16 bit Unicode characters. The default is iso8859-1.  Long file-
              names are stored on disk in(1,8) Unicode format.

       quiet  Turn on the quiet flag.  Attempts to chown(1,2) or chmod(1,2) 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(1,n) system.


Mount options for hfs
       creator=cccc, type=cccc
              Set  the  creator/type  values as shown by the MacOS finder used
              for creating new files.  Default values: '????'.

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

       dir_umask=n, file_umask=n, umask=n
              Set  the  umask  used for all directories, all regular files, or
              all files and directories.  Defaults to the umask of the current
              process.

       session=n
              Select  the  CDROM  session  to mount.  Defaults to leaving that
              decision to the CDROM driver.  This option will fail  with  any-
              thing but a CDROM as underlying device.

       part=n Select partition number n from the device.  Only makes sense for
              CDROMS.  Defaults to not parsing the partition table at all.

       quiet  Don't complain about invalid mount(2,8) options.


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(1,8) octal.

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

       conv=binary / conv=text / conv=auto(5,8)
              For conv=text, delete some random(3,4,6) CRs (in(1,8) particular,  all  fol-
              lowed by NL) when reading a file.  For conv=auto(5,8), choose more or
              less(1,3)  at  random(3,4,6)  between  conv=binary   and   conv=text.    For
              conv=binary, just read(2,n,1 builtins) what is in(1,8) the file. This is the default.

       nocheck
              Do not abort(3,7) 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(1,8)  a  8.3  format  (i.e.,  DOS-like
       restrictions on filename length), and in(1,8) addition all characters are in(1,8)
       upper case.  Also there is no field  for  file(1,n)  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(1,8) use, the filesystem is indistinguishable from  a  normal  UNIX  file(1,n)
       system (except that it is read-only, of course).

       norock Disable the use of Rock Ridge extensions, even if(3,n) available. Cf.
              map.

       nojoliet
              Disable the use of Microsoft Joliet extensions, even  if(3,n)  avail-
              able. Cf. map.

       check=r[elaxed] / check=s[trict]
              With  check=relaxed, a filename is first converted to lower case
              before doing the  lookup.   This  is  probably  only  meaningful
              together with norock and map=normal.  (Default: check=strict.)

       uid=value and gid=value
              Give  all  files  in(1,8) the file(1,n) system the indicated user or group
              id, possibly overriding the information found in(1,8) 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(3,n) present.

       mode=value
              For  non-Rock  Ridge volumes, give all files the indicated mode.
              (Default: read(2,n,1 builtins) permission for everybody.)   Since  Linux  2.1.37
              one  no  longer  needs to specify the mode in(1,8) decimal. (Octal is
              indicated by a leading 0.)

       unhide Also show hidden and associated files.  (If the  ordinary  files
              and the associated or hidden files have the same filenames, this
              may make the ordinary files inaccessible.)

       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 settings used to be  very  dan-
              gerous, possibly leading to silent data corruption.)

       cruft  If  the high byte of the file(1,n) length contains other garbage, set(7,n,1 builtins)
              this mount(2,8) option to ignore the high  order  bits  of  the  file(1,n)
              length.  This implies that a file(1,n) cannot be larger than 16MB.

       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 specifying them only
       makes sense when using discs encoded using  Microsoft's  Joliet  exten-
       sions.

       iocharset=value
              Character set(7,n,1 builtins) to use for converting 16 bit Unicode characters on
              CD to 8 bit characters. The default is iso8859-1.

       utf8   Convert 16 bit Unicode characters on CD to UTF-8.


Mount options for jfs
       iocharset=name
              Character set(7,n,1 builtins) to use for converting from Unicode to ASCII.   The
              default  is  to  do  no conversion.  Use iocharset=utf8 for UTF8
              translations.  This requires CONFIG_NLS_UTF8 to be  set(7,n,1 builtins)  in(1,8)  the
              kernel .config file.

       resize=value
              Resize  the  volume to value blocks. JFS only supports growing a
              volume, not shrinking it. This option is  only  valid  during  a
              remount,  when the volume is mounted read-write. The resize key-
              word with no value will grow the volume to the full size of  the
              partition.

       nointegrity
              Do  not write(1,2) to the journal.  The primary use of this option is
              to allow for higher performance when  restoring  a  volume  from
              backup  media.  The integrity of the volume is not guaranteed if(3,n)
              the system abnormally abends.

       integrity
              Default.  Commit metadata changes  to  the  journal.   Use  this
              option to remount a volume where the nointegrity option was pre-
              viously specified in(1,8) order to restore normal behavior.

       errors=continue / errors=remount-ro / errors=panic
              Define the behaviour when  an  error(8,n)  is  encountered.   (Either
              ignore  errors  and just mark the file(1,n) system erroneous and con-
              tinue, or remount the file(1,n) system read-only, or panic  and  halt
              the system.)

       noquota / quota(1,8) / usrquota / grpquota
              These options are accepted but ignored.


Mount options for minix
       None.


Mount options for msdos
       See  mount(2,8) options for fat.  If the msdos file(1,n) system detects an incon-
       sistency, it reports an error(8,n) and sets the file(1,n) system  read-only.  The
       file(1,n) system can be made writeable again by remounting it.


Mount options for ncpfs
       Just  like  nfs,  the ncpfs implementation expects a binary argument (a
       struct ncp_mount_data) to the mount(2,8) system call. This argument is  con-
       structed  by  ncpmount(8)  and the current version(1,3,5) of mount(2,8) (2.12) does
       not know anything about ncpfs.


Mount options for nfs
       Instead of a textual option string(3,n), parsed by the kernel, the nfs  file(1,n)
       system  expects  a  binary argument of type struct nfs_mount_data.  The
       program  mount(2,8)  itself  parses  the  following  options  of  the   form
       `tag=value',  and  puts(3,n)  them  in(1,8)  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, mounthost=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.  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.)

       hard   The  program  accessing a file(1,n) on a NFS mounted file(1,n) system will
              hang when the server crashes. The process cannot be  interrupted
              or  killed unless you also specify intr.  When the NFS server is
              back online the program will continue undisturbed from where  it
              was. This is probably what you want.

       soft   This  option  allows the kernel to time(1,2,n) out if(3,n) the nfs server is
              not responding for some time. The time(1,2,n)  can  be  specified  with
              timeo=time(1,2,n).   This  option  might  be  useful if(3,n) your nfs server
              sometimes doesn't respond or will be rebooted while some process
              tries  to  get  a  file(1,n) from the server.  Usually it just causes
              lots of trouble.

       nolock Do not use locking. Do not start lockd.


Mount options for ntfs
       iocharset=name
              Character set(7,n,1 builtins) to use when returning file(1,n)  names.   Unlike  VFAT,
              NTFS  suppresses  names  that  contain unconvertible characters.
              Deprecated.

       nls=name
              New name for the option earlier called iocharset.

       utf8   Use UTF-8 for converting file(1,n) 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(3,n)  and  1 a byteswapped bigendian
              encoding.

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

       uid=value, gid=value and umask=value
              Set the file(1,n) permission on the filesystem.  The umask  value  is
              given in(1,8) octal.  By default, the files are owned by root and not
              readable by somebody else.


Mount options for proc(5,n)
       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(2,8)
       options.


Mount options for reiserfs
       Reiserfs  is  a  journaling filesystem.  The reiserfs mount(2,8) options are
       more fully described at http://www.namesys.com/mount-options.html.

       conv   Instructs version(1,3,5) 3.6 reiserfs software to mount(2,8) a  version(1,3,5)  3.5
              file(1,n)  system,  using  the  3.6 format for newly created objects.
              This file(1,n) system will no longer be compatible with reiserfs  3.5
              tools.

       hash=rupasov / hash=tea / hash=r5 / hash=detect
              Choose  which  hash  function  reiserfs  will  use to find files
              within directories.

              rupasov
                     A hash invented by Yury Yu. Rupasov.  It is fast and pre-
                     serves  locality,  mapping  lexicographically  close(2,7,n) file(1,n)
                     names to close(2,7,n) hash values.  This option  should  not  be
                     used, as it causes a high probability of hash collisions.

              tea    A   Davis-Meyer   function    implemented    by    Jeremy
                     Fitzhardinge.   It  uses hash permuting bits in(1,8) the name.
                     It gets(3,n) high randomness and, therefore,  low  probability
                     of hash collisions at some CPU cost.  This may be used if(3,n)
                     EHASHCOLLISION errors are experienced with the r5 hash.

              r5     A modified version(1,3,5) of the rupasov hash.  It  is  used  by
                     default and is the best choice unless the file(1,n) system has
                     huge directories and unusual file-name patterns.

              detect Instructs mount(2,8) to detect which hash function is  in(1,8)  use
                     by examining the file(1,n) system being mounted,  and to write(1,2)
                     this information into the reiserfs  superblock.  This  is
                     only useful on the first mount(2,8) of an old format file(1,n) sys-
                     tem.

       hashed_relocation
              Tunes the block allocator. This may provide performance improve-
              ments in(1,8) some situations.

       no_unhashed_relocation
              Tunes the block allocator. This may provide performance improve-
              ments in(1,8) some situations.

       noborder
              Disable the border allocator  algorithm  invented  by  Yury  Yu.
              Rupasov.  This may provide performance improvements in(1,8) some sit-
              uations.

       nolog  Disable  journalling.  This  will  provide  slight   performance
              improvements in(1,8) 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.   Implementation  of
              nolog is a work in(1,8) progress.

       notail By  default,  reiserfs  stores  small  files  and  `file(1,n)  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(1,8) the  journal,  but  do  not
              actually mount(2,8) the file(1,n) system. Mainly used by reiserfsck.

       resize=number
              A remount option which permits online expansion of reiserfs par-
              titions.  Instructs reiserfs to assume that the device has  num-
              ber  blocks.  This option is designed for use with devices which
              are under logical volume management (LVM).  There is  a  special
              resizer     utility     which     can     be    obtained    from
              ftp://ftp.namesys.com/pub/reiserfsprogs.


Mount options for romfs
       None.


Mount options for smbfs
       Just like nfs, the smbfs implementation expects a  binary  argument  (a
       struct  smb_mount_data) to the mount(2,8) system call. This argument is con-
       structed by smbmount(8) and the current version(1,3,5) of  mount(2,8)  (2.12)  does
       not know anything about smbfs.


Mount options for sysv
       None.


Mount options for tmpfs
       The  following  parameters  accept(2,8)  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 maximum size of the filesystem.   The  size  is
              given  in(1,8)  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(1,8) octal.

       uid=   Set the default user.

       unhide Show otherwise hidden files.

       undelete
              Show deleted files in(1,8) lists.

       nostrict
              Unset strict conformance.

       iocharset
              Set the NLS character set.

       bs=    Set the block size. (May not work unless 2048.)

       novrs  Skip volume sequence recognition.

       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(1,n) system widely used in(1,8) different operating systems.
              The  problem  are differences among implementations. Features of
              some implementations are undocumented(2,3), so its hard to  recognize
              the type of ufs automatically.  That's why the user must specify
              the type of ufs by mount(2,8) option.  Possible values are:

              old    Old format of  ufs,  this  is  the  default,  read(2,n,1 builtins)  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.

              hp     For filesystems created by HP-UX, read-only.

              nextstep
                     For filesystems created by  NeXTStep  (on  NeXT  station)
                     (currently read(2,n,1 builtins) only).

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

              openstep
                     For  filesystems  created  by  OpenStep  (currently  read(2,n,1 builtins)
                     only).  The same filesystem type is also used by  Mac  OS
                     X.


       onerror=value
              Set behaviour on error:

              panic  If an error(8,n) is encountered, cause a kernel panic.

              [lock|umount|repair]
                     These mount(2,8) options don't do anything at present; when an
                     error(8,n) is encountered only a console(4,n) message is printed.


Mount options for umsdos
       See mount(2,8) options for msdos.  The dotsOK option is explicitly killed by
       umsdos.


Mount options for vfat
       First  of  all,  the  mount(2,8) options for fat are recognized.  The dotsOK
       option is explicitly killed by vfat.  Furthermore, 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(3,n) used, where u is the unicode charac-
              ter, is: ':', (u & 0x3f), ((u>>6) & 0x3f), (u>>12).

       posix  Allow two files with names that only differ in(1,8) 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(3,n) of Unicode that is
              used by the console. It can be be  enabled  for  the  filesystem
              with  this option.  If `uni_xlate' gets(3,n) set(7,n,1 builtins), UTF8 gets(3,n) 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(1,n) exists,
              it will always be preferred display. There are four modes:

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

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

              winnt  Display the shortname as is; store a long name  when  the
                     short name is not all lower case or all upper case.

              mixed  Display  the short name as is; store a long name when the
                     short name is not all upper case.

       The default is "lower".


Mount options for usbfs
       devuid=uid and devgid=gid and devmode=mode
              Set the owner and group and mode of  the  device  files  in(1,8)  the
              usbfs  file(1,n)  system (default: uid=gid=0, mode=0644). The mode is
              given in(1,8) octal.

       busuid=uid and busgid=gid and busmode=mode
              Set the owner and group and mode of the bus directories  in(1,8)  the
              usbfs  file(1,n)  system (default: uid=gid=0, mode=0555). The mode is
              given in(1,8) octal.

       listuid=uid and listgid=gid and listmode=mode
              Set the owner and group and mode of the file(1,n)  devices  (default:
              uid=gid=0, mode=0444). The mode is given in(1,8) octal.


Mount options for xenix
       None.


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
              pagesize,  13  (8K  bytes)  is also a valid size.  The preferred
              buffered I/O size can also be  altered  on  an  individual  file(1,n)
              basis using the ioctl(2) system call.

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

       logbufs=value
              Set  the  number  of in-memory log buffers.  Valid numbers range
              from 2-8 inclusive.  The default value is 8 buffers for filesys-
              tems  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 performance on some workloads  at
              the  cost  of the memory 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(1,3)  mem-
              ory 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 sec-
              tion 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(1,n) is read.

       norecovery
              The filesystem will be mounted without running log recovery.  If
              the  filesystem  was  not  cleanly unmounted, it is likely to be
              inconsistent when mounted in(1,8) norecovery  mode.   Some  files  or
              directories  may not be accessible because of this.  Filesystems
              mounted norecovery must be mounted read-only or the  mount(2,8)  will
              fail.

       nouuid Ignore  the  filesystem  uuid.  This avoids errors for duplicate
              uuids.

       osyncisdsync
              Make writes to files opened with the O_SYNC flag set(7,n,1 builtins)  behave  as
              if(3,n)  the  O_DSYNC flag had been used instead.  This can result in(1,8)
              better performance without compromising data safety.  However if(3,n)
              this  option  is in(1,8) effect, timestamp updates from O_SYNC writes
              can be lost if(3,n) the system crashes.

       quota(1,8) / usrquota / uqnoenforce
              User disk quota(1,8)  accounting  enabled,  and  limits  (optionally)
              enforced.

       grpquota / gqnoenforce
              Group  disk  quota(1,8)  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(1,8) 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(1,2,n),  then  the  mount(2,8)  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(1,8)  the superblock if(3,n) the underlying
              disk layout changes after the filesystem has been created.   The
              swidth  option  is  required if(3,n) the sunit option has been speci-
              fied, 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(1,3,5)
       2.1.21 xiafs is no longer part of the kernel source.


THE LOOP DEVICE
       One further possible type is a mount(2,8) via the loop device. For  example,
       the command

         mount(2,8) /tmp/fdimage /mnt -t msdos -o loop=/dev/loop3,blocksize=1024

       will  set(7,n,1 builtins)  up  the  loop  device  /dev/loop3  to correspond to the file(1,n)
       /tmp/fdimage, and then mount(2,8) this device on /mnt.

       This type of mount(2,8) knows about three options, namely loop,  offset  and
       encryption,  that are really options to losetup(8).  (These options can
       be used in(1,8) addition to those specific to the filesystem type.)

       If no explicit loop device is mentioned (but just an option  `-o  loop'
       is  given), then mount(2,8) 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(1,2) to
       /proc(5,n)/mounts  then  any loop device allocated by mount(2,8) will be freed by
       umount.  You can also free a loop device by hand, using  `losetup  -d',
       see losetup(8).


RETURN CODES
       mount(2,8) has the following return codes (the bits can be ORed):

       0      success

       1      incorrect invocation or permissions

       2      system error(8,n) (out of memory, cannot fork, no more loop devices)

       4      internal mount(2,8) bug or missing nfs support in(1,8) mount(2,8)

       8      user interrupt

       16     problems writing or locking /etc/mtab

       32     mount(2,8) failure

       64     some mount(2,8) succeeded


FILES
       /etc/fstab        file(1,n) system table

       /etc/mtab         table of mounted file(1,n) systems

       /etc/mtab~        lock file(1,n)

       /etc/mtab.tmp     temporary file(1,n)

       /etc/filesystems  a list of filesystem types to try


SEE ALSO
       mount(2,8)(2),  umount(2),  fstab(5),  umount(8), swapon(2,8)(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(1,n) system to cause a crash.

       Some  Linux file(1,n) systems don't support -o sync(1,2,8) and -o dirsync (the ext2
       and ext3 file(1,n) systems do support synchronous updates (a  la  BSD)  when
       mounted with the sync(1,2,8) option).

       The  -o remount may not be able to change mount(2,8) 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).

       Mount  by  label  or uuid will work only if(3,n) your devices have the names
       listed in(1,8) /proc(5,n)/partitions.  In particular, it may  well  fail  if(3,n)  the
       kernel was compiled with devfs but devfs is not mounted.

HISTORY
       A mount(2,8) command existed in(1,8) Version 5 AT&T UNIX.



Linux 2.6                         2004-12-16                          MOUNT(8)

References for this manual (incoming links)