1 .\" Copyright (c) 1996 Andries Brouwer
3 .\" This page is somewhat derived from a page that was
4 .\" (c) 1980, 1989, 1991 The Regents of the University of California
5 .\" and had been heavily modified by Rik Faith and myself.
6 .\" (Probably no BSD text remains.)
7 .\" Fragments of text were written by Werner Almesberger, Remy Card,
8 .\" Stephen Tweedie and Eric Youngdale.
10 .\" This is free documentation; you can redistribute it and/or
11 .\" modify it under the terms of the GNU General Public License as
12 .\" published by the Free Software Foundation; either version 2 of
13 .\" the License, or (at your option) any later version.
15 .\" The GNU General Public License's references to "object code"
16 .\" and "executables" are to be interpreted as the output of any
17 .\" document formatting or typesetting system, including
18 .\" intermediate and printed output.
20 .\" This manual is distributed in the hope that it will be useful,
21 .\" but WITHOUT ANY WARRANTY; without even the implied warranty of
22 .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 .\" GNU General Public License for more details.
25 .\" You should have received a copy of the GNU General Public
26 .\" License along with this manual; if not, write to the Free
27 .\" Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
30 .\" 960705, aeb: version for mount-2.7g
31 .\" 970114, aeb: xiafs and ext are dead; romfs is new
32 .\" 970623, aeb: -F option
33 .\" 970914, reg: -s option
34 .\" 981111, K.Garloff: /etc/filesystems
35 .\" 990111, aeb: documented /sbin/mount.smbfs
36 .\" 990730, Yann Droneaud <lch@multimania.com>: updated page
37 .\" 991214, Elrond <Elrond@Wunder-Nett.org>: added some docs on devpts
38 .\" 010714, Michael K. Johnson <johnsonm@redhat.com> added -O
39 .\" 010725, Nikita Danilov <NikitaDanilov@Yahoo.COM>: reiserfs options
40 .\" 011124, Karl Eichwalder <ke@gnu.franken.de>: tmpfs options
42 .TH MOUNT 8 "14 September 1997" "Linux 2.0" "Linux Programmer's Manual"
44 mount \- mount a file system
48 .BI "mount \-a [\-fFnrsvw] [\-t " vfstype "] [\-O " optlist ]
50 .BI "mount [\-fnrsvw] [\-o " options " [,...]] " "device " | " dir"
52 .BI "mount [\-fnrsvw] [\-t " vfstype "] [\-o " options "] " "device dir"
54 All files accessible in a Unix system are arranged in one big
55 tree, the file hierarchy, rooted at
57 These files can be spread out over several devices. The
59 command serves to attach the file system found on some device
60 to the big file tree. Conversely, the
62 command will detach it again.
64 The standard form of the
69 .BI "mount \-t" " type device dir"
71 This tells the kernel to attach the file system found on
77 The previous contents (if any) and owner and mode of
79 become invisible, and as long as this file system remains mounted,
82 refers to the root of the file system on
85 Three forms of invocation do not actually mount anything:
90 prints a help message;
95 prints a version string; and just
97 .BI "mount [-l] [-t" " type" ]
99 lists all mounted file systems (of type
101 The option \-l adds the (ext2, ext3 and XFS) labels in this listing.
104 .\" In fact since 2.3.99. At first the syntax was mount -t bind.
105 Since Linux 2.4.0 it is possible to remount part of the
106 file hierarchy somewhere else. The call is
109 .B "mount --bind olddir newdir"
111 After this call the same contents is accessible in two places.
113 This call attaches only (part of) a single filesystem, not possible
114 submounts. The entire file hierarchy including submounts is attached
118 .B "mount --rbind olddir newdir"
120 .\" available since Linux 2.4.11.
122 Since Linux 2.5.1 it is possible to atomically move a subtree
123 to another place. The call is
126 .B "mount --move olddir newdir"
131 file system is not associated with a special device, and when
132 mounting it, an arbitrary keyword, such as
134 can be used instead of a device specification.
135 (The customary choice
137 is less fortunate: the error message `none busy' from
141 Most devices are indicated by a file name (of a block special device), like
143 but there are other possibilities. For example, in the case of an NFS mount,
146 .IR knuth.cwi.nl:/dir .
147 It is possible to indicate a block special device using its
148 volume label or UUID (see the \-L and \-U options below).
154 may contain lines describing what devices are usually
155 mounted where, using which options. This file is used in three ways:
160 .BI "mount \-a [\-t " type "] [\-O " optlist ]
162 (usually given in a bootscript) causes all file systems mentioned in
164 (of the proper type and/or having or not having the proper options)
165 to be mounted as indicated, except for those whose line contains the
169 option will make mount fork, so that the
170 filesystems are mounted simultaneously.
172 (ii) When mounting a file system mentioned in
174 it suffices to give only the device, or only the mount point.
176 (iii) Normally, only the superuser can mount file systems.
181 option on a line, then anybody can mount the corresponding system.
186 .B "/dev/cdrom /cd iso9660 ro,user,noauto,unhide"
188 any user can mount the iso9660 file system found on his CDROM
192 .B "mount /dev/cdrom"
199 For more details, see
201 Only the user that mounted a filesystem can unmount it again.
202 If any user should be able to unmount, then use
211 option is similar to the
213 option, with the restriction that the user must be the owner
214 of the special file. This may be useful e.g. for
216 if a login script makes the console user owner of this device.
222 maintain a list of currently mounted file systems in the file
224 If no arguments are given to
226 this list is printed.
230 filesystem is mounted (say at
236 have very similar contents. The former has somewhat
237 more information, such as the mount options used,
238 but is not necessarily up-to-date (cf. the
240 option below). It is possible to replace
242 by a symbolic link to
244 but some information is lost that way, and in particular
245 working with the loop device will be less convenient,
246 and using the "user" option will fail.
249 The full set of options used by an invocation of
251 is determined by first extracting the
252 options for the file system from the
254 table, then applying any options specified by the
256 argument, and finally applying a
258 option, when present.
260 Options available for the
268 Print a help message.
274 Mount all filesystems (of the given types) mentioned in
278 (Used in conjunction with
280 Fork off a new incarnation of mount for each device.
281 This will do the mounts on different devices or different NFS servers
283 This has the advantage that it is faster; also NFS timeouts go in
284 parallel. A disadvantage is that the mounts are done in undefined order.
285 Thus, you cannot use this option if you want to mount both
291 Causes everything to be done except for the actual system call; if it's not
292 obvious, this ``fakes'' mounting the file system. This option is useful in
295 flag to determine what the
297 command is trying to do. It can also be used to add entries for devices
298 that were mounted earlier with the -n option.
301 Don't call the /sbin/mount.<filesystem> helper even if it exists.
304 Add the ext2, ext3 and XFS labels in the mount output. Mount must have
305 permission to read the disk device (e.g. be suid root) for this to work.
306 One can set such a label for ext2 or ext3 using the
308 utility, or for XFS using
312 Mount without writing in
314 This is necessary for example when
316 is on a read-only file system.
319 In case of a loop mount with encryption, read the passphrase from
322 instead of from the terminal.
325 Tolerate sloppy mount options rather than failing. This will ignore
326 mount options not supported by a filesystem type. Not all filesystems
327 support this option. This option exists for support of the Linux
328 autofs\-based automounter.
331 Mount the file system read-only. A synonym is
335 Mount the file system read/write. This is the default. A synonym is
339 Mount the partition that has the specified
343 Mount the partition that has the specified
345 These two options require the file
347 (present since Linux 2.1.116) to exist.
350 The argument following the
352 is used to indicate the file system type. The file system types which are
353 currently supported are:
389 Note that coherent, sysv and xenix are equivalent and that
393 will be removed at some point in the future \(em use
395 instead. Since kernel version 2.1.21 the types
399 do not exist anymore.
401 For most types all the
403 program has to do is issue a simple
405 system call, and no detailed knowledge of the filesystem type is required.
406 For a few types however (like nfs, smbfs, ncpfs) ad hoc code is
407 necessary. The nfs ad hoc code is built in, but smbfs and ncpfs
408 have a separate mount program. In order to make it possible to
409 treat all types in a uniform way, mount will execute the program
411 (if that exists) when called with type
413 Since various versions of the
415 program have different calling conventions,
417 may have to be a shell script that sets up the desired call.
421 is the default. If no
423 option is given, or if the
425 type is specified, the superblock is probed for the filesystem type
447 If this probe fails, mount will try to read the file
448 .IR /etc/filesystems ,
449 or, if that does not exist,
450 .IR /proc/filesystems .
451 All of the filesystem types listed there will be tried,
452 except for those that are labeled "nodev" (e.g.,
459 ends in a line with a single * only, mount will read
465 type may be useful for user-mounted floppies.
468 can be useful to change the probe order (e.g., to try vfat before msdos)
469 or if you use a kernel module autoloader.
470 Warning: the probing uses a heuristic (the presence of appropriate `magic'),
471 and could recognize the wrong filesystem type, possibly with catastrophic
472 consequences. If your data is valuable, don't ask
476 More than one type may be specified in a comma separated
477 list. The list of file system types can be prefixed with
479 to specify the file system types on which no action should be taken.
480 (This can be meaningful with the
484 For example, the command:
487 .B "mount \-a \-t nomsdos,ext"
489 mounts all file systems except those of type
496 Used in conjunction with
498 to limit the set of filesystems to which the
502 in this regard except that it is useless except in the context of
504 For example, the command:
507 .B "mount \-a \-O no_netdev"
509 mounts all file systems except those which have the option
511 specified in the options field in the
517 in that each option is matched exactly; a leading
519 at the beginning of one option does not negate the rest.
525 options are cumulative in effect; that is, the command
527 .B "mount \-a \-t ext2 \-O _netdev"
529 mounts all ext2 filesystems with the _netdev option, not all filesystems
530 that are either ext2 or have the _netdev option specified.
534 Options are specified with a
536 flag followed by a comma separated string of options.
537 Some of these options are only useful when they appear in the
539 file. The following options apply to any file system that is being
540 mounted (but not every file system actually honors them - e.g., the
542 option today has effect only for ext2, ext3 and ufs):
546 All I/O to the file system should be done asynchronously.
549 Update inode access time for each access. This is the default.
552 Can be mounted with the
558 .BR rw ", " suid ", " dev ", " exec ", " auto ", " nouser ", and " async.
561 Interpret character or block special devices on the file system.
564 Permit execution of binaries.
567 The filesystem resides on a device that requires network access
568 (used to prevent the system from attempting to mount these filesystems
569 until the network has been enabled on the system).
572 Do not update inode access times on this file system (e.g, for faster
573 access on the news spool to speed up news servers).
576 Can only be mounted explicitly (i.e., the
578 option will not cause the file system to be mounted).
581 Do not interpret character or block special devices on the file
585 Do not allow execution of any binaries on the mounted file system.
586 This option might be useful for a server that has file systems containing
587 binaries for architectures other than its own.
590 Do not allow set-user-identifier or set-group-identifier bits to take
591 effect. (This seems safe, but is in fact rather unsafe if you have
592 suidperl(1) installed.)
595 Forbid an ordinary (i.e., non-root) user to mount the file system.
599 Attempt to remount an already-mounted file system. This is commonly
600 used to change the mount flags for a file system, especially to make a
601 readonly file system writeable. It does not change device or mount point.
604 Mount the file system read-only.
607 Mount the file system read-write.
610 Allow set-user-identifier or set-group-identifier bits to take
614 All I/O to the file system should be done synchronously.
617 All directory updates within the file system should be done synchronously.
618 This affects the following system calls: creat, link, unlink, symlink,
619 mkdir, rmdir, mknod and rename.
622 Allow an ordinary user to mount the file system.
623 The name of the mounting user is written to mtab so that he can unmount
624 the file system again.
625 This option implies the options
626 .BR noexec ", " nosuid ", and " nodev
627 (unless overridden by subsequent options, as in the option line
628 .BR user,exec,dev,suid ).
631 Allow every user to mount and unmount the file system.
632 This option implies the options
633 .BR noexec ", " nosuid ", and " nodev
634 (unless overridden by subsequent options, as in the option line
635 .BR users,exec,dev,suid ).
639 Remount a subtree somewhere else (so that its contents are available
640 in both places). See above.
643 Move a subtree to some other place. See above.
645 .SH "FILESYSTEM SPECIFIC MOUNT OPTIONS"
646 The following options apply only to certain file systems.
647 We sort them by file system. They all follow the
650 .SH "Mount options for adfs"
652 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
653 Set the owner and group of the files in the file system (default: uid=gid=0).
655 \fBownmask=\fP\fIvalue\fP and \fBothmask=\fP\fIvalue\fP
656 Set the permission mask for ADFS 'owner' permissions and 'other' permissions,
657 respectively (default: 0700 and 0077, respectively).
659 .IR /usr/src/linux/Documentation/filesystems/adfs.txt .
660 .SH "Mount options for affs"
662 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
663 Set the owner and group of the root of the file system (default: uid=gid=0,
668 without specified value, the uid and gid of the current process are taken).
670 \fBsetuid=\fP\fIvalue\fP and \fBsetgid=\fP\fIvalue\fP
671 Set the owner and group of all files.
674 Set the mode of all files to
676 disregarding the original permissions.
677 Add search permission to directories that have read permission.
678 The value is given in octal.
681 Do not allow any changes to the protection bits on the file system.
684 Set uid and gid of the root of the file system to the uid and gid
685 of the mount point upon the first sync or umount, and then
686 clear this option. Strange...
689 Print an informational message for each successful mount.
692 Prefix used before volume name, when following a link.
695 Prefix (of length at most 30) used before '/' when following a symbolic link.
698 (Default: 2.) Number of unused blocks at the start of the device.
701 Give explicitly the location of the root block.
704 Give blocksize. Allowed values are 512, 1024, 2048, 4096.
706 .BR grpquota " / " noquota " / " quota " / " usrquota
707 These options are accepted but ignored.
708 (However, quota utilities may react to such strings in
711 .SH "Mount options for coherent"
714 .SH "Mount options for devpts"
715 The devpts file system is a pseudo file system, traditionally mounted on
717 In order to acquire a pseudo terminal, a process opens
719 the number of the pseudo terminal is then made available to the process
720 and the pseudo terminal slave can be accessed as
721 .IR /dev/pts/ <number>.
723 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
724 This sets the owner or the group of newly created PTYs to
725 the specified values. When nothing is specified, they will
726 be set to the UID and GID of the creating process.
727 For example, if there is a tty group with GID 5, then
729 will cause newly created PTYs to belong to the tty group.
732 Set the mode of newly created PTYs to the specified value.
738 makes "mesg y" the default on newly created PTYs.
740 .SH "Mount options for ext"
742 Note that the `ext' file system is obsolete. Don't use it.
743 Since Linux version 2.1.21 extfs is no longer part of the kernel source.
745 .SH "Mount options for ext2"
746 The `ext2' file system is the standard Linux file system.
747 Due to a kernel bug, it may be mounted with random mount options
748 (fixed in Linux 2.0.4).
750 .BR bsddf " / " minixdf
751 Set the behaviour for the
755 behaviour is to return in the
757 field the total number of blocks of the file system, while the
759 behaviour (which is the default) is to subtract the overhead blocks
760 used by the ext2 file system and not available for file storage. Thus
764 % mount /k -o minixdf; df /k; umount /k
765 Filesystem 1024-blocks Used Available Capacity Mounted on
766 /dev/sda6 2630655 86954 2412169 3% /k
767 % mount /k -o bsddf; df /k; umount /k
768 Filesystem 1024-blocks Used Available Capacity Mounted on
769 /dev/sda6 2543714 13 2412169 0% /k
772 (Note that this example shows that one can add command line options
773 to the options given in
777 .BR check " / " check=normal " / " check=strict
778 Set checking level. When at least one of these options is set (and
780 is set by default) the inodes and blocks bitmaps are checked upon mount
781 (which can take half a minute or so on a big disk, and is rather useless).
782 With strict checking, block deallocation checks that the block to free
785 .BR check=none " / " nocheck
786 No checking is done. This is fast. Recent kernels do not have a
787 check option anymore - checking with
792 Print debugging info upon each (re)mount.
794 .BR errors=continue " / " errors=remount-ro " / " errors=panic
795 Define the behaviour when an error is encountered.
796 (Either ignore errors and just mark the file system erroneous and continue,
797 or remount the file system read-only, or panic and halt the system.)
798 The default is set in the filesystem superblock, and can be
802 .BR grpid " or " bsdgroups " / " nogrpid " or " sysvgroups
803 These options define what group id a newly created file gets.
806 is set, it takes the group id of the directory in which it is created;
807 otherwise (the default) it takes the fsgid of the current process, unless
808 the directory has the setgid bit set, in which case it takes the gid
809 from the parent directory, and also gets the setgid bit set
810 if it is a directory itself.
812 \fBresgid=\fP\fIn\fP and \fBresuid=\fP\fIn\fP
813 The ext2 file system reserves a certain percentage of the available
814 space (by default 5%, see
818 These options determine who can use the reserved blocks.
819 (Roughly: whoever has the specified uid, or belongs to the specified group.)
822 Instead of block 1, use block
824 as superblock. This could be useful when the filesystem has been damaged.
825 (Earlier, copies of the superblock would be made every 8192 blocks: in
826 block 1, 8193, 16385, ... (and one got hundreds or even thousands
827 of copies on a big filesystem). Since version 1.08,
829 has a \-s (sparse superblock) option to reduce the number of backup
830 superblocks, and since version 1.15 this is the default. Note
831 that this may mean that ext2 filesystems created by a recent
833 cannot be mounted r/w under Linux 2.0.*.)
834 The block number here uses 1k units. Thus, if you want to use logical
835 block 32768 on a filesystem with 4k blocks, use "sb=131072".
837 .BR grpquota " / " noquota " / " quota " / " usrquota
838 These options are accepted but ignored.
842 Disables 32-bit UIDs and GIDs. This is for interoperability with older
843 kernels which only store and expect 16-bit values.
846 .SH "Mount options for ext3"
847 The `ext3' file system is version of the ext2 file system which has been
848 enhanced with journalling. It supports the same options as ext2 as
849 well as the following additions:
852 .\" Mount the file system in abort mode, as if a fatal error has occurred.
855 Update the ext3 file system's journal to the current format.
858 When a journal already exists, this option is ignored. Otherwise, it
859 specifies the number of the inode which will represent the ext3 file system's
860 journal file; ext3 will create a new journal, overwriting the old contents
861 of the file whose inode number is
865 Do not load the ext3 file system's journal on mounting.
867 .BR data=journal " / " data=ordered " / " data=writeback
868 Specifies the journalling mode for file data. Metadata is always journaled.
872 All data is committed into the journal prior to being written into the
876 This is the default mode. All data is forced directly out to the main file
877 system prior to its metadata being committed to the journal.
880 Data ordering is not preserved - data may be written into the main
881 file system after its metadata has been committed to the journal.
882 This is rumoured to be the highest-throughput option. It guarantees
883 internal file system integrity, however it can allow old data to appear
884 in files after a crash and journal recovery.
886 .SH "Mount options for fat"
889 is not a separate filesystem, but a common part of the
896 .BR blocksize=512 " / " blocksize=1024 " / " blocksize=2048
897 Set blocksize (default 512).
899 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
900 Set the owner and group of all files. (Default: the uid and gid
901 of the current process.)
904 Set the umask (the bitmask of the permissions that are
906 present). The default is the umask of the current process.
907 The value is given in octal.
910 Set the umask applied to directories only.
911 The default is the umask of the current process.
912 The value is given in octal. Present since 2.5.43.
915 Set the umask applied to regular files only.
916 The default is the umask of the current process.
917 The value is given in octal. Present since 2.5.43.
920 Three different levels of pickyness can be chosen:
924 Upper and lower case are accepted and equivalent, long name parts are
926 .I verylongname.foobar
929 leading and embedded spaces are accepted in each name part (name and extension).
932 Like "relaxed", but many special characters (*, ?, <, spaces, etc.) are
933 rejected. This is the default.
936 Like "normal", but names may not contain long parts and special characters
937 that are sometimes used on Linux, but are not accepted by MS-DOS are
938 rejected. (+, =, spaces, etc.)
942 Sets the codepage for converting to shortname characters on FAT
943 and VFAT filesystems. By default, codepage 437 is used.
945 .BR conv=b[inary] " / " conv=t[ext] " / " conv=a[uto]
948 file system can perform CRLF<-->NL (MS-DOS text format to UNIX text
949 format) conversion in the kernel. The following conversion modes are
954 no translation is performed. This is the default.
957 CRLF<-->NL translation is performed on all files.
960 CRLF<-->NL translation is performed on all files that don't have a
961 "well-known binary" extension. The list of known extensions can be found at
964 (as of 2.0, the list is: exe, com, bin, app, sys, drv, ovl, ovr, obj,
965 lib, dll, pif, arc, zip, lha, lzh, zoo, tar, z, arj, tz, taz, tzp, tpz,
966 gz, tgz, deb, gif, bmp, tif, gl, jpg, pcx, tfm, vf, gf, pk, pxl, dvi).
968 Programs that do computed lseeks won't like in-kernel text conversion.
969 Several people have had their data ruined by this translation. Beware!
971 For file systems mounted in binary mode, a conversion tool
972 (fromdos/todos) is available.
975 .BI cvf_format= module
976 Forces the driver to use the CVF (Compressed Volume File) module
978 instead of auto-detection. If the kernel supports kmod, the
979 cvf_format=xxx option also controls on-demand CVF module loading.
981 .BI cvf_option= option
982 Option passed to the CVF module.
987 flag. A version string and a list of file system parameters will be
988 printed (these data are also printed if the parameters appear to be
991 .BR fat=12 " / " fat=16 " / " fat=32
992 Specify a 12, 16 or 32 bit fat. This overrides
993 the automatic FAT type detection routine. Use with caution!
996 Character set to use for converting between 8 bit characters
997 and 16 bit Unicode characters. The default is iso8859-1.
998 Long filenames are stored on disk in Unicode format.
1003 flag. Attempts to chown or chmod files do not return errors,
1004 although they fail. Use with caution!
1006 .B "sys_immutable, showexec, dots, nodots, dotsOK=[yes|no]"
1007 Various misguided attempts to force Unix or DOS conventions
1008 onto a FAT file system.
1010 .SH "Mount options for hpfs"
1012 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
1013 Set the owner and group of all files. (Default: the uid and gid
1014 of the current process.)
1017 Set the umask (the bitmask of the permissions that are
1019 present). The default is the umask of the current process.
1020 The value is given in octal.
1022 .BR case=lower " / " case=asis
1023 Convert all files names to lower case, or leave them.
1027 .BR conv=binary " / " conv=text " / " conv=auto
1030 delete some random CRs (in particular, all followed by NL)
1031 when reading a file.
1034 choose more or less at random between
1035 .BR conv=binary " and " conv=text .
1038 just read what is in the file. This is the default.
1041 Do not abort mounting when certain consistency checks fail.
1043 .SH "Mount options for iso9660"
1044 ISO 9660 is a standard describing a filesystem structure to be used
1045 on CD-ROMs. (This filesystem type is also seen on some DVDs. See also the
1051 filenames appear in a 8.3 format (i.e., DOS-like restrictions on filename
1052 length), and in addition all characters are in upper case. Also there is
1053 no field for file ownership, protection, number of links, provision for
1054 block/character devices, etc.
1056 Rock Ridge is an extension to iso9660 that provides all of these unix like
1057 features. Basically there are extensions to each directory record that
1058 supply all of the additional information, and when Rock Ridge is in use,
1059 the filesystem is indistinguishable from a normal UNIX file system (except
1060 that it is read-only, of course).
1063 Disable the use of Rock Ridge extensions, even if available. Cf.\&
1067 Disable the use of Microsoft Joliet extensions, even if available. Cf.\&
1070 .BR check=r[elaxed] " / " check=s[trict]
1073 a filename is first converted to lower case before doing the lookup.
1074 This is probably only meaningful together with
1081 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
1082 Give all files in the file system the indicated user or group id,
1083 possibly overriding the information found in the Rock Ridge extensions.
1087 .BR map=n[ormal] " / " map=o[ff] " / " map=a[corn]
1088 For non-Rock Ridge volumes, normal name translation maps upper
1089 to lower case ASCII, drops a trailing `;1', and converts `;' to `.'.
1092 no name translation is done. See
1099 but also apply Acorn extensions if present.
1102 For non-Rock Ridge volumes, give all files the indicated mode.
1103 (Default: read permission for everybody.)
1104 Since Linux 2.1.37 one no longer needs to specify the mode in
1105 decimal. (Octal is indicated by a leading 0.)
1108 Also show hidden and associated files.
1109 (If the ordinary files and the associated or hidden files have
1110 the same filenames, this may make the ordinary files inaccessible.)
1112 .B block=[512|1024|2048]
1113 Set the block size to the indicated value.
1117 .BR conv=a[uto] " / " conv=b[inary] " / " conv=m[text] " / " conv=t[ext]
1120 Since Linux 1.3.54 this option has no effect anymore.
1121 (And non-binary settings used to be very dangerous,
1122 possibly leading to silent data corruption.)
1125 If the high byte of the file length contains other garbage,
1126 set this mount option to ignore the high order bits of the file length.
1127 This implies that a file cannot be larger than 16MB.
1128 The `cruft' option is set automatically if the entire CDROM
1129 has a weird size (negative, or more than 800MB). It is also
1130 set when volume sequence numbers other than 0 or 1 are seen.
1133 Select number of session on multisession CD. (Since 2.3.4.)
1136 Session begins from sector xxx. (Since 2.3.4.)
1138 The following options are the same as for vfat and specifying them only makes
1139 sense when using discs encoded using Microsoft's Joliet extensions.
1141 .BI iocharset= value
1142 Character set to use for converting 16 bit Unicode characters on CD
1143 to 8 bit characters. The default is iso8859-1.
1146 Convert 16 bit Unicode characters on CD to UTF-8.
1148 .SH "Mount options for minix"
1151 .SH "Mount options for msdos"
1152 See mount options for fat.
1155 file system detects an inconsistency, it reports an error and sets the file
1156 system read-only. The file system can be made writeable again by remounting
1159 .SH "Mount options for ncpfs"
1161 .IR nfs ", the " ncpfs
1162 implementation expects a binary argument (a
1163 .IR "struct ncp_mount_data" )
1164 to the mount system call. This argument is constructed by
1166 and the current version of
1168 (2.12) does not know anything about ncpfs.
1170 .SH "Mount options for nfs"
1171 Instead of a textual option string, parsed by the kernel, the
1173 file system expects a binary argument of type
1174 .IR "struct nfs_mount_data" .
1177 itself parses the following options of the form `tag=value',
1178 and puts them in the structure mentioned:
1191 .BI mounthost= name,
1199 is accepted but ignored.
1200 Also the following Boolean options, possibly preceded by
1217 Especially useful options include
1219 .B rsize=8192,wsize=8192
1220 This will make your nfs connection faster than with the default
1221 buffer size of 4096. (NFSv2 does not work with larger values of
1227 The program accessing a file on a NFS mounted file system will hang
1228 when the server crashes. The process cannot be interrupted or
1229 killed unless you also specify
1231 When the NFS server is back online the program will continue undisturbed
1232 from where it was. This is probably what you want.
1235 This option allows the kernel to time out if the nfs server is not
1236 responding for some time. The time can be
1239 This option might be useful if your nfs server sometimes doesn't respond
1240 or will be rebooted while some process tries to get a file from the server.
1241 Usually it just causes lots of trouble.
1244 Do not use locking. Do not start lockd.
1246 .SH "Mount options for ntfs"
1249 Character set to use when returning file names.
1250 Unlike VFAT, NTFS suppresses names that contain
1251 unconvertible characters.
1254 Use UTF-8 for converting file names.
1256 .B uni_xlate=[0|1|2]
1257 For 0 (or `no' or `false'), do not use escape sequences
1258 for unknown Unicode characters.
1259 For 1 (or `yes' or `true') or 2, use vfat-style 4-byte escape sequences
1260 starting with ":". Here 2 give a little-endian encoding
1261 and 1 a byteswapped bigendian encoding.
1264 If enabled (posix=1), the file system distinguishes between
1265 upper and lower case. The 8.3 alias names are presented as
1266 hard links instead of being suppressed.
1268 \fBuid=\fP\fIvalue\fP, \fBgid=\fP\fIvalue\fP and \fBumask=\fP\fIvalue\fP
1269 Set the file permission on the filesystem.
1270 The umask value is given in octal.
1271 By default, the files are owned by root and not readable by somebody else.
1273 .SH "Mount options for proc"
1275 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
1276 These options are recognized, but have no effect as far as I can see.
1278 .SH "Mount options for ramfs"
1279 Ramfs is a memory based filesystem. Mount it and you have it. Unmount it
1280 and it is gone. Present since Linux 2.3.99pre4.
1281 There are no mount options.
1283 .SH "Mount options for reiserfs"
1284 Reiserfs is a journaling filesystem.
1285 The reiserfs mount options are more fully described at
1286 .IR http://www.namesys.com/mount-options.html .
1289 Instructs version 3.6 reiserfs software to mount a version 3.5 file system,
1290 using the 3.6 format for newly created objects. This file system will no
1291 longer be compatible with reiserfs 3.5 tools.
1293 .BR hash=rupasov " / " hash=tea " / " hash=r5 " / " hash=detect
1294 Choose which hash function reiserfs will use to find files within directories.
1298 A hash invented by Yury Yu. Rupasov. It is fast and preserves locality,
1299 mapping lexicographically close file names to close hash values.
1300 This option should not be used, as it causes a high probability of hash
1304 A Davis-Meyer function implemented by Jeremy Fitzhardinge.
1305 It uses hash permuting bits in the name. It gets high randomness
1306 and, therefore, low probability of hash collisions at come CPU cost.
1307 This may be used if EHASHCOLLISION errors are experienced with the r5 hash.
1310 A modified version of the rupasov hash. It is used by default and is
1311 the best choice unless the file system has huge directories and
1312 unusual file-name patterns.
1317 to detect which hash function is in use by examining
1318 the file system being mounted, and to write this information into
1319 the reiserfs superblock. This is only useful on the first mount of
1320 an old format file system.
1323 .BR hashed_relocation
1324 Tunes the block allocator. This may provide performance improvements
1327 .BR no_unhashed_relocation
1328 Tunes the block allocator. This may provide performance improvements
1332 Disable the border allocator algorithm invented by Yury Yu. Rupasov.
1333 This may provide performance improvements in some situations.
1336 Disable journalling. This will provide slight performance improvements in
1337 some situations at the cost of losing reiserfs's fast recovery from crashes.
1338 Even with this option turned on, reiserfs still performs all journalling
1339 operations, save for actual writes into its journalling area. Implementation
1342 is a work in progress.
1345 By default, reiserfs stores small files and `file tails' directly into its
1346 tree. This confuses some utilities such as
1348 This option is used to disable packing of files into the tree.
1351 Replay the transactions which are in the journal, but do not actually
1352 mount the file system. Mainly used by
1356 A remount option which permits online expansion of reiserfs partitions.
1357 Instructs reiserfs to assume that the device has
1360 This option is designed for use with devices which are under logical
1361 volume management (LVM).
1364 utility which can be obtained from
1365 .IR ftp://ftp.namesys.com/pub/reiserfsprogs .
1367 .SH "Mount options for romfs"
1370 .SH "Mount options for smbfs"
1372 .IR nfs ", the " smbfs
1373 implementation expects a binary argument (a
1374 .IR "struct smb_mount_data" )
1375 to the mount system call. This argument is constructed by
1377 and the current version of
1379 (2.12) does not know anything about smbfs.
1381 .SH "Mount options for sysv"
1384 .SH "Mount options for tmpfs"
1385 The following parameters accept a suffix
1390 for Ki, Mi, Gi (binary kilo, mega and giga) and can be changed on remount.
1393 Override default size of the filesystem.
1394 The size is given in bytes, and rounded down to entire pages.
1395 The default is half of the memory.
1398 Set number of blocks.
1401 Set number of inodes.
1404 Set initial permissions of the root directory.
1406 .SH "Mount options for udf"
1407 udf is the "Universal Disk Format" filesystem defined by the Optical
1408 Storage Technology Association, and is often used for DVD-ROM.
1413 Set the default group.
1416 Set the default umask.
1417 The value is given in octal.
1420 Set the default user.
1423 Show otherwise hidden files.
1426 Show deleted files in lists.
1429 Set strict conformance (unused).
1438 Set the block size. (May not work unless 2048.)
1441 Skip volume sequence recognition.
1444 Set the CDROM session counting from 0. Default: last session.
1447 Override standard anchor location. Default: 256.
1450 Override the VolumeDesc location. (unused)
1453 Override the PartitionDesc location. (unused)
1456 Set the last block of the filesystem.
1459 Override the fileset block location. (unused)
1462 Override the root directory location. (unused)
1464 .SH "Mount options for ufs"
1467 UFS is a file system widely used in different operating systems.
1468 The problem are differences among implementations. Features of some
1469 implementations are undocumented, so its hard to recognize the
1470 type of ufs automatically.
1471 That's why the user must specify the type of ufs by mount option.
1472 Possible values are:
1476 Old format of ufs, this is the default, read only.
1477 (Don't forget to give the \-r option.)
1480 For filesystems created by a BSD-like system (NetBSD,FreeBSD,OpenBSD).
1483 For filesystems created by SunOS or Solaris on Sparc.
1486 For filesystems created by Solaris on x86.
1489 For filesystems created by NeXTStep (on NeXT station) (currently read only).
1492 For NextStep CDROMs (block_size == 2048), read-only.
1495 For filesystems created by OpenStep (currently read only).
1496 The same filesystem type is also used by Mac OS X.
1501 Set behaviour on error:
1505 If an error is encountered, cause a kernel panic.
1507 .B [lock|umount|repair]
1508 These mount options don't do anything at present;
1509 when an error is encountered only a console message is printed.
1512 .SH "Mount options for umsdos"
1513 See mount options for msdos.
1516 option is explicitly killed by
1519 .SH "Mount options for vfat"
1520 First of all, the mount options for
1525 option is explicitly killed by
1527 Furthermore, there are
1530 Translate unhandled Unicode characters to special escaped sequences.
1531 This lets you backup and restore filenames that are created with any
1532 Unicode characters. Without this option, a '?' is used when no
1533 translation is possible. The escape character is ':' because it is
1534 otherwise illegal on the vfat filesystem. The escape sequence
1535 that gets used, where u is the unicode character,
1536 is: ':', (u & 0x3f), ((u>>6) & 0x3f), (u>>12).
1539 Allow two files with names that only differ in case.
1542 First try to make a short name without sequence number,
1547 UTF8 is the filesystem safe 8-bit encoding of Unicode that is used
1548 by the console. It can be be enabled for the filesystem with this option.
1549 If `uni_xlate' gets set, UTF8 gets disabled.
1551 .B shortname=[lower|win95|winnt|mixed]
1553 Defines the behaviour for creation and display of filenames which fit into
1554 8.3 characters. If a long name for a file exists, it will always be
1555 preferred display. There are four modes:
1559 Force the short name to lower case upon display; store a long name when
1560 the short name is not all upper case.
1563 Force the short name to upper case upon display; store a long name when
1564 the short name is not all upper case.
1567 Display the shortname as is; store a long name when the short name is
1568 not all lower case or all upper case.
1571 Display the short name as is; store a long name when the short name is not
1575 The default is "lower".
1577 .SH "Mount options for xenix"
1580 .SH "Mount options for xfs"
1583 Sets the preferred buffered I/O size (default size is 64K).
1585 must be expressed as the logarithm (base2) of the desired I/O size.
1586 Valid values for this option are 14 through 16, inclusive
1587 (i.e. 16K, 32K, and 64K bytes).
1588 On machines with a 4K pagesize, 13 (8K bytes) is also a valid
1590 The preferred buffered I/O size can also be altered on an individual
1591 file basis using the
1596 Enable the DMAPI (Data Management API) event callouts.
1599 Set the number of in-memory log buffers.
1600 Valid numbers range from 2-8 inclusive.
1601 The default value is 8 buffers for filesystems with a blocksize of 64K,
1602 4 buffers for filesystems with a blocksize of 32K,
1603 3 buffers for filesystems with a blocksize of 16K,
1604 and 2 buffers for all other configurations.
1605 Increasing the number of buffers may increase performance on
1606 some workloads at the cost of the memory used for the
1607 additional log buffers and their associated control structures.
1610 Set the size of each in-memory log buffer.
1611 Valid sizes are 16384 (16K) and 32768 (32K).
1612 The default value for machines with more than 32MB of memory is 32768,
1613 machines with less memory use 16384 by default.
1615 \fBlogdev=\fP\fIdevice\fP and \fBrtdev=\fP\fIdevice\fP
1616 Use an external log (metadata journal) and/or real-time device.
1617 An XFS filesystem has up to three parts: a data section, a log section,
1618 and a real-time section.
1619 The real-time section is optional, and the log section can be separate
1620 from the data section or contained within it.
1625 Data allocations will not be aligned at stripe unit boundaries.
1628 Access timestamps are not updated when a file is read.
1631 The filesystem will be mounted without running log recovery.
1632 If the filesystem was not cleanly unmounted, it is likely to
1633 be inconsistent when mounted in
1636 Some files or directories may not be accessible because of this.
1639 must be mounted read-only or the mount will fail.
1642 Make writes to files opened with the O_SYNC flag set behave
1643 as if the O_DSYNC flag had been used instead.
1644 This can result in better performance without compromising
1646 However if this option is in effect, timestamp updates from
1647 O_SYNC writes can be lost if the system crashes.
1649 .BR quota " / " usrquota " / " uqnoenforce
1650 User disk quota accounting enabled, and limits (optionally) enforced.
1652 .BR grpquota " / " gqnoenforce
1653 Group disk quota accounting enabled and limits (optionally) enforced.
1655 \fBsunit=\fP\fIvalue\fP and \fBswidth=\fP\fIvalue\fP
1656 Used to specify the stripe unit and width for a RAID device or a stripe
1659 must be specified in 512-byte block units.
1660 If this option is not specified and the filesystem was made on a stripe
1661 volume or the stripe width or unit were specified for the RAID device at
1662 mkfs time, then the mount system call will restore the value from the
1664 For filesystems that are made directly on RAID devices, these options can be
1665 used to override the information in the superblock if the underlying disk
1666 layout changes after the filesystem has been created.
1669 option is required if the
1671 option has been specified,
1672 and must be a multiple of the
1676 .SH "Mount options for xiafs"
1677 None. Although nothing is wrong with xiafs, it is not used much,
1678 and is not maintained. Probably one shouldn't use it.
1679 Since Linux version 2.1.21 xiafs is no longer part of the kernel source.
1681 .SH "THE LOOP DEVICE"
1682 One further possible type is a mount via the loop device. For example,
1686 .B " mount /tmp/fdimage /mnt -t msdos -o loop=/dev/loop3,blocksize=1024"
1689 will set up the loop device
1691 to correspond to the file
1693 and then mount this device on
1695 This type of mount knows about three options, namely
1696 .BR loop ", " offset " and " encryption ,
1697 that are really options to
1699 If no explicit loop device is mentioned
1700 (but just an option `\fB\-o loop\fP' is given), then
1702 will try to find some unused loop device and use that.
1703 If you are not so unwise as to make
1707 then any loop device allocated by
1711 You can also free a loop device by hand, using `losetup -d', see
1716 has the following return codes (the bits can be ORed):
1722 incorrect invocation or permissions
1725 system error (out of memory, cannot fork, no more loop devices)
1739 problems writing or locking /etc/mtab
1745 some mount succeeded
1752 table of mounted file systems
1775 It is possible for a corrupted file system to cause a crash.
1777 Some Linux file systems don't support
1778 .B "\-o sync and \-o dirsync"
1779 (the ext2 and ext3 file systems
1781 support synchronous updates (a la BSD) when mounted with the
1787 may not be able to change mount parameters (all
1788 .IR ext2fs -specific
1791 are changeable with a remount, for example, but you can't change
1800 command existed in Version 5 AT&T UNIX.
projects / thirdparty / util-linux.git / blob