1 .\" Copyright (c) 1996-2004 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 "2004-12-16" "Linux 2.6" "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.
112 One can also remount a single file (on a single file).
114 This call attaches only (part of) a single filesystem, not possible
115 submounts. The entire file hierarchy including submounts is attached
119 .B "mount --rbind olddir newdir"
121 .\" available since Linux 2.4.11.
123 Note that the filesystem mount options will remain the same as those
124 on the original mount point, and cannot be changed by passing the -o
125 option along with --bind/--rbind.
127 Since Linux 2.5.1 it is possible to atomically move a mounted tree
128 to another place. The call is
131 .B "mount --move olddir newdir"
136 file system is not associated with a special device, and when
137 mounting it, an arbitrary keyword, such as
139 can be used instead of a device specification.
140 (The customary choice
142 is less fortunate: the error message `none busy' from
146 Most devices are indicated by a file name (of a block special device), like
148 but there are other possibilities. For example, in the case of an NFS mount,
151 .IR knuth.cwi.nl:/dir .
152 It is possible to indicate a block special device using its
153 volume label or UUID (see the \-L and \-U options below).
159 may contain lines describing what devices are usually
160 mounted where, using which options. This file is used in three ways:
165 .BI "mount \-a [\-t " type "] [\-O " optlist ]
167 (usually given in a bootscript) causes all file systems mentioned in
169 (of the proper type and/or having or not having the proper options)
170 to be mounted as indicated, except for those whose line contains the
174 option will make mount fork, so that the
175 filesystems are mounted simultaneously.
177 (ii) When mounting a file system mentioned in
179 it suffices to give only the device, or only the mount point.
181 (iii) Normally, only the superuser can mount file systems.
186 option on a line, anybody can mount the corresponding system.
191 .B "/dev/cdrom /cd iso9660 ro,user,noauto,unhide"
193 any user can mount the iso9660 file system found on his CDROM
197 .B "mount /dev/cdrom"
204 For more details, see
206 Only the user that mounted a filesystem can unmount it again.
207 If any user should be able to unmount, then use
216 option is similar to the
218 option, with the restriction that the user must be the owner
219 of the special file. This may be useful e.g. for
221 if a login script makes the console user owner of this device.
224 option is similar, with the restriction that the user must be
225 member of the group of the special file.
231 maintain a list of currently mounted file systems in the file
233 If no arguments are given to
235 this list is printed.
239 filesystem is mounted (say at
245 have very similar contents. The former has somewhat
246 more information, such as the mount options used,
247 but is not necessarily up-to-date (cf. the
249 option below). It is possible to replace
251 by a symbolic link to
253 and especially when you have very large numbers of mounts
254 things will be much faster with that symlink,
255 but some information is lost that way, and in particular
256 working with the loop device will be less convenient,
257 and using the "user" option will fail.
260 The full set of options used by an invocation of
262 is determined by first extracting the
263 options for the file system from the
265 table, then applying any options specified by the
267 argument, and finally applying a
269 option, when present.
271 Options available for the
279 Print a help message.
285 Mount all filesystems (of the given types) mentioned in
289 (Used in conjunction with
291 Fork off a new incarnation of mount for each device.
292 This will do the mounts on different devices or different NFS servers
294 This has the advantage that it is faster; also NFS timeouts go in
295 parallel. A disadvantage is that the mounts are done in undefined order.
296 Thus, you cannot use this option if you want to mount both
302 Causes everything to be done except for the actual system call; if it's not
303 obvious, this ``fakes'' mounting the file system. This option is useful in
306 flag to determine what the
308 command is trying to do. It can also be used to add entries for devices
309 that were mounted earlier with the -n option.
312 Don't call the /sbin/mount.<filesystem> helper even if it exists.
315 Add the ext2, ext3 and XFS labels in the mount output. Mount must have
316 permission to read the disk device (e.g. be suid root) for this to work.
317 One can set such a label for ext2 or ext3 using the
319 utility, or for XFS using
321 or for reiserfs using
322 .BR reiserfstune (8).
325 Mount without writing in
327 This is necessary for example when
329 is on a read-only file system.
332 In case of a loop mount with encryption, read the passphrase from
335 instead of from the terminal.
338 Tolerate sloppy mount options rather than failing. This will ignore
339 mount options not supported by a filesystem type. Not all filesystems
340 support this option. This option exists for support of the Linux
341 autofs\-based automounter.
344 Mount the file system read-only. A synonym is
348 Mount the file system read/write. This is the default. A synonym is
352 Mount the partition that has the specified
356 Mount the partition that has the specified
358 These two options require the file
360 (present since Linux 2.1.116) to exist.
363 The argument following the
365 is used to indicate the file system type. The file system types which are
366 currently supported include:
403 Note that coherent, sysv and xenix are equivalent and that
407 will be removed at some point in the future \(em use
409 instead. Since kernel version 2.1.21 the types
413 do not exist anymore. Earlier,
418 For most types all the
420 program has to do is issue a simple
422 system call, and no detailed knowledge of the filesystem type is required.
423 For a few types however (like nfs, smbfs, ncpfs) ad hoc code is
424 necessary. The nfs ad hoc code is built in, but smbfs and ncpfs
425 have a separate mount program. In order to make it possible to
426 treat all types in a uniform way, mount will execute the program
428 (if that exists) when called with type
430 Since various versions of the
432 program have different calling conventions,
434 may have to be a shell script that sets up the desired call.
438 option is given, or if the
440 type is specified, mount will try to guess the desired type.
441 If mount was compiled with the blkid library, the guessing is done
442 by this library. Otherwise, mount guesses itself by probing the
443 superblock; if that does not turn up anything that looks familiar,
444 mount will try to read the file
445 .IR /etc/filesystems ,
446 or, if that does not exist,
447 .IR /proc/filesystems .
448 All of the filesystem types listed there will be tried,
449 except for those that are labeled "nodev" (e.g.,
456 ends in a line with a single * only, mount will read
462 type may be useful for user-mounted floppies.
465 can be useful to change the probe order (e.g., to try vfat before msdos
466 or ext3 before ext2) or if you use a kernel module autoloader.
467 Warning: the probing uses a heuristic (the presence of appropriate `magic'),
468 and could recognize the wrong filesystem type, possibly with catastrophic
469 consequences. If your data is valuable, don't ask
473 More than one type may be specified in a comma separated
474 list. The list of file system types can be prefixed with
476 to specify the file system types on which no action should be taken.
477 (This can be meaningful with the
481 For example, the command:
484 .B "mount \-a \-t nomsdos,ext"
486 mounts all file systems except those of type
493 Used in conjunction with
495 to limit the set of filesystems to which the
499 in this regard except that it is useless except in the context of
501 For example, the command:
504 .B "mount \-a \-O no_netdev"
506 mounts all file systems except those which have the option
508 specified in the options field in the
514 in that each option is matched exactly; a leading
516 at the beginning of one option does not negate the rest.
522 options are cumulative in effect; that is, the command
524 .B "mount \-a \-t ext2 \-O _netdev"
526 mounts all ext2 filesystems with the _netdev option, not all filesystems
527 that are either ext2 or have the _netdev option specified.
531 Options are specified with a
533 flag followed by a comma separated string of options.
534 Some of these options are only useful when they appear in the
536 file. The following options apply to any file system that is being
537 mounted (but not every file system actually honors them - e.g., the
539 option today has effect only for ext2, ext3 and ufs):
543 All I/O to the file system should be done asynchronously.
546 Update inode access time for each access. This is the default.
549 Can be mounted with the
555 .BR rw ", " suid ", " dev ", " exec ", " auto ", " nouser ", and " async.
558 Interpret character or block special devices on the file system.
561 Permit execution of binaries.
564 Allow an ordinary (i.e., non-root) user to mount the file system if one
565 of his groups matches the group of the device.
566 This option implies the options
567 .BR nosuid " and " nodev
568 (unless overridden by subsequent options, as in the option line
569 .BR group,dev,suid ).
572 Allow mandatory locks on this filesystem. See
576 The filesystem resides on a device that requires network access
577 (used to prevent the system from attempting to mount these filesystems
578 until the network has been enabled on the system).
581 Do not update inode access times on this file system (e.g, for faster
582 access on the news spool to speed up news servers).
585 Can only be mounted explicitly (i.e., the
587 option will not cause the file system to be mounted).
590 Do not interpret character or block special devices on the file
594 Do not allow direct execution of any binaries on the mounted file system.
595 (Until recently it was possible to run binaries anyway using a command like
596 /lib/ld*.so /mnt/binary. This trick fails since Linux 2.4.25 / 2.6.0.)
599 Do not allow mandatory locks on this filesystem.
602 Do not allow set-user-identifier or set-group-identifier bits to take
603 effect. (This seems safe, but is in fact rather unsafe if you have
604 suidperl(1) installed.)
607 Forbid an ordinary (i.e., non-root) user to mount the file system.
611 Allow an ordinary (i.e., non-root) user to mount the file system if he
612 is the owner of the device.
613 This option implies the options
614 .BR nosuid " and " nodev
615 (unless overridden by subsequent options, as in the option line
616 .BR owner,dev,suid ).
619 Attempt to remount an already-mounted file system. This is commonly
620 used to change the mount flags for a file system, especially to make a
621 readonly file system writeable. It does not change device or mount point.
624 Mount the file system read-only.
627 Mount the file system read-write.
630 Allow set-user-identifier or set-group-identifier bits to take
634 All I/O to the file system should be done synchronously.
637 All directory updates within the file system should be done synchronously.
638 This affects the following system calls: creat, link, unlink, symlink,
639 mkdir, rmdir, mknod and rename.
642 Allow an ordinary user to mount the file system.
643 The name of the mounting user is written to mtab so that he can unmount
644 the file system again.
645 This option implies the options
646 .BR noexec ", " nosuid ", and " nodev
647 (unless overridden by subsequent options, as in the option line
648 .BR user,exec,dev,suid ).
651 Allow every user to mount and unmount the file system.
652 This option implies the options
653 .BR noexec ", " nosuid ", and " nodev
654 (unless overridden by subsequent options, as in the option line
655 .BR users,exec,dev,suid ).
659 Remount a subtree somewhere else (so that its contents are available
660 in both places). See above.
663 Move a subtree to some other place. See above.
665 .SH "FILESYSTEM SPECIFIC MOUNT OPTIONS"
666 The following options apply only to certain file systems.
667 We sort them by file system. They all follow the
671 What options are supported depends a bit on the running kernel.
672 More info may be found in the kernel source subdirectory
673 .IR Documentation/filesystems .
675 .SH "Mount options for adfs"
677 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
678 Set the owner and group of the files in the file system (default: uid=gid=0).
680 \fBownmask=\fP\fIvalue\fP and \fBothmask=\fP\fIvalue\fP
681 Set the permission mask for ADFS 'owner' permissions and 'other' permissions,
682 respectively (default: 0700 and 0077, respectively).
684 .IR /usr/src/linux/Documentation/filesystems/adfs.txt .
685 .SH "Mount options for affs"
687 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
688 Set the owner and group of the root of the file system (default: uid=gid=0,
693 without specified value, the uid and gid of the current process are taken).
695 \fBsetuid=\fP\fIvalue\fP and \fBsetgid=\fP\fIvalue\fP
696 Set the owner and group of all files.
699 Set the mode of all files to
701 disregarding the original permissions.
702 Add search permission to directories that have read permission.
703 The value is given in octal.
706 Do not allow any changes to the protection bits on the file system.
709 Set uid and gid of the root of the file system to the uid and gid
710 of the mount point upon the first sync or umount, and then
711 clear this option. Strange...
714 Print an informational message for each successful mount.
717 Prefix used before volume name, when following a link.
720 Prefix (of length at most 30) used before '/' when following a symbolic link.
723 (Default: 2.) Number of unused blocks at the start of the device.
726 Give explicitly the location of the root block.
729 Give blocksize. Allowed values are 512, 1024, 2048, 4096.
731 .BR grpquota " / " noquota " / " quota " / " usrquota
732 These options are accepted but ignored.
733 (However, quota utilities may react to such strings in
736 .SH "Mount options for coherent"
739 .SH "Mount options for devpts"
740 The devpts file system is a pseudo file system, traditionally mounted on
742 In order to acquire a pseudo terminal, a process opens
744 the number of the pseudo terminal is then made available to the process
745 and the pseudo terminal slave can be accessed as
746 .IR /dev/pts/ <number>.
748 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
749 This sets the owner or the group of newly created PTYs to
750 the specified values. When nothing is specified, they will
751 be set to the UID and GID of the creating process.
752 For example, if there is a tty group with GID 5, then
754 will cause newly created PTYs to belong to the tty group.
757 Set the mode of newly created PTYs to the specified value.
763 makes "mesg y" the default on newly created PTYs.
765 .SH "Mount options for ext"
767 Note that the `ext' file system is obsolete. Don't use it.
768 Since Linux version 2.1.21 extfs is no longer part of the kernel source.
770 .SH "Mount options for ext2"
771 The `ext2' file system is the standard Linux file system.
772 .\" Due to a kernel bug, it may be mounted with random mount options
773 .\" (fixed in Linux 2.0.4).
774 Since Linux 2.5.46, for most mount options the default
775 is determined by the filesystem superblock. Set them with
779 Support POSIX Access Control Lists (or not).
780 .\" requires CONFIG_EXT2_FS_POSIX_ACL
782 .BR bsddf " / " minixdf
783 Set the behaviour for the
787 behaviour is to return in the
789 field the total number of blocks of the file system, while the
791 behaviour (which is the default) is to subtract the overhead blocks
792 used by the ext2 file system and not available for file storage. Thus
796 % mount /k -o minixdf; df /k; umount /k
797 Filesystem 1024-blocks Used Available Capacity Mounted on
798 /dev/sda6 2630655 86954 2412169 3% /k
799 % mount /k -o bsddf; df /k; umount /k
800 Filesystem 1024-blocks Used Available Capacity Mounted on
801 /dev/sda6 2543714 13 2412169 0% /k
804 (Note that this example shows that one can add command line options
805 to the options given in
809 .\" Before Linux 2.3.99-pre3:
810 .\" .BR check " / " check=normal " / " check=strict
811 .\" Set checking level. When at least one of these options is set (and
813 .\" is set by default) the inodes and blocks bitmaps are checked upon mount
814 .\" (which can take half a minute or so on a big disk, and is rather useless).
815 .\" With strict checking, block deallocation checks that the block to free
816 .\" is in the data zone.
817 .\" Since 2.3.99-pre3 but before 2.6.0-test7 every string check=foo
818 .\" was equivalent to just check. Since 2.6.0-test7 only check is accepted.
820 Check filesystem (block and inode bitmaps) at mount time.
821 .\" requires CONFIG_EXT2_CHECK
823 .BR check=none " / " nocheck
824 No checking is done at mount time. This is the default. This is fast.
827 every now and then, e.g. at boot time.
830 Print debugging info upon each (re)mount.
832 .BR errors=continue " / " errors=remount-ro " / " errors=panic
833 Define the behaviour when an error is encountered.
834 (Either ignore errors and just mark the file system erroneous and continue,
835 or remount the file system read-only, or panic and halt the system.)
836 The default is set in the filesystem superblock, and can be
840 .BR grpid " or " bsdgroups " / " nogrpid " or " sysvgroups
841 These options define what group id a newly created file gets.
844 is set, it takes the group id of the directory in which it is created;
845 otherwise (the default) it takes the fsgid of the current process, unless
846 the directory has the setgid bit set, in which case it takes the gid
847 from the parent directory, and also gets the setgid bit set
848 if it is a directory itself.
850 .BR grpquota " / " noquota " / " quota " / " usrquota
851 These options are accepted but ignored.
854 Do not attach buffer_heads to file pagecache. (Since 2.5.49.)
857 Disables 32-bit UIDs and GIDs. This is for interoperability with older
858 kernels which only store and expect 16-bit values.
860 .BR oldalloc " or " orlov
861 Use old allocator or Orlov allocator for new inodes. Orlov is default.
863 \fBresgid=\fP\fIn\fP and \fBresuid=\fP\fIn\fP
864 The ext2 file system reserves a certain percentage of the available
865 space (by default 5%, see
869 These options determine who can use the reserved blocks.
870 (Roughly: whoever has the specified uid, or belongs to the specified group.)
873 Instead of block 1, use block
875 as superblock. This could be useful when the filesystem has been damaged.
876 (Earlier, copies of the superblock would be made every 8192 blocks: in
877 block 1, 8193, 16385, ... (and one got thousands of copies on
878 a big filesystem). Since version 1.08,
880 has a \-s (sparse superblock) option to reduce the number of backup
881 superblocks, and since version 1.15 this is the default. Note
882 that this may mean that ext2 filesystems created by a recent
884 cannot be mounted r/w under Linux 2.0.*.)
885 The block number here uses 1k units. Thus, if you want to use logical
886 block 32768 on a filesystem with 4k blocks, use "sb=131072".
888 .BR user_xattr " / " nouser_xattr
889 Support "user." extended attributes (or not).
890 .\" requires CONFIG_EXT2_FS_XATTR
893 .SH "Mount options for ext3"
894 The `ext3' file system is a version of the ext2 file system which has been
895 enhanced with journalling. It supports the same options as ext2 as
896 well as the following additions:
899 .\" Mount the file system in abort mode, as if a fatal error has occurred.
902 Update the ext3 file system's journal to the current format.
905 When a journal already exists, this option is ignored. Otherwise, it
906 specifies the number of the inode which will represent the ext3 file system's
907 journal file; ext3 will create a new journal, overwriting the old contents
908 of the file whose inode number is
912 Do not load the ext3 file system's journal on mounting.
914 .BR data=journal " / " data=ordered " / " data=writeback
915 Specifies the journalling mode for file data. Metadata is always journaled.
916 To use modes other than
918 on the root file system, pass the mode to the kernel as boot parameter, e.g.
919 .IR rootflags=data=journal .
923 All data is committed into the journal prior to being written into the
927 This is the default mode. All data is forced directly out to the main file
928 system prior to its metadata being committed to the journal.
931 Data ordering is not preserved - data may be written into the main
932 file system after its metadata has been committed to the journal.
933 This is rumoured to be the highest-throughput option. It guarantees
934 internal file system integrity, however it can allow old data to appear
935 in files after a crash and journal recovery.
939 Sync all data and metadata every
941 seconds. The default value is 5 seconds. Zero means default.
943 .SH "Mount options for fat"
946 is not a separate filesystem, but a common part of the
953 .BR blocksize=512 " / " blocksize=1024 " / " blocksize=2048
954 Set blocksize (default 512).
956 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
957 Set the owner and group of all files.
958 (Default: the uid and gid of the current process.)
961 Set the umask (the bitmask of the permissions that are
963 present). The default is the umask of the current process.
964 The value is given in octal.
967 Set the umask applied to directories only.
968 The default is the umask of the current process.
969 The value is given in octal.
970 .\" Present since Linux 2.5.43.
973 Set the umask applied to regular files only.
974 The default is the umask of the current process.
975 The value is given in octal.
976 .\" Present since Linux 2.5.43.
979 Three different levels of pickyness can be chosen:
983 Upper and lower case are accepted and equivalent, long name parts are
985 .I verylongname.foobar
988 leading and embedded spaces are accepted in each name part (name and extension).
991 Like "relaxed", but many special characters (*, ?, <, spaces, etc.) are
992 rejected. This is the default.
995 Like "normal", but names may not contain long parts and special characters
996 that are sometimes used on Linux, but are not accepted by MS-DOS are
997 rejected. (+, =, spaces, etc.)
1001 Sets the codepage for converting to shortname characters on FAT
1002 and VFAT filesystems. By default, codepage 437 is used.
1004 .BR conv=b[inary] " / " conv=t[ext] " / " conv=a[uto]
1007 file system can perform CRLF<-->NL (MS-DOS text format to UNIX text
1008 format) conversion in the kernel. The following conversion modes are
1013 no translation is performed. This is the default.
1016 CRLF<-->NL translation is performed on all files.
1019 CRLF<-->NL translation is performed on all files that don't have a
1020 "well-known binary" extension. The list of known extensions can be found at
1023 (as of 2.0, the list is: exe, com, bin, app, sys, drv, ovl, ovr, obj,
1024 lib, dll, pif, arc, zip, lha, lzh, zoo, tar, z, arj, tz, taz, tzp, tpz,
1025 gz, tgz, deb, gif, bmp, tif, gl, jpg, pcx, tfm, vf, gf, pk, pxl, dvi).
1027 Programs that do computed lseeks won't like in-kernel text conversion.
1028 Several people have had their data ruined by this translation. Beware!
1030 For file systems mounted in binary mode, a conversion tool
1031 (fromdos/todos) is available.
1034 .BI cvf_format= module
1035 Forces the driver to use the CVF (Compressed Volume File) module
1037 instead of auto-detection. If the kernel supports kmod, the
1038 cvf_format=xxx option also controls on-demand CVF module loading.
1040 .BI cvf_option= option
1041 Option passed to the CVF module.
1046 flag. A version string and a list of file system parameters will be
1047 printed (these data are also printed if the parameters appear to be
1050 .BR fat=12 " / " fat=16 " / " fat=32
1051 Specify a 12, 16 or 32 bit fat. This overrides
1052 the automatic FAT type detection routine. Use with caution!
1054 .BI iocharset= value
1055 Character set to use for converting between 8 bit characters
1056 and 16 bit Unicode characters. The default is iso8859-1.
1057 Long filenames are stored on disk in Unicode format.
1062 flag. Attempts to chown or chmod files do not return errors,
1063 although they fail. Use with caution!
1065 .B "sys_immutable, showexec, dots, nodots, dotsOK=[yes|no]"
1066 Various misguided attempts to force Unix or DOS conventions
1067 onto a FAT file system.
1069 .SH "Mount options for hfs"
1071 .BI creator= cccc ", type=" cccc
1072 Set the creator/type values as shown by the MacOS finder
1073 used for creating new files. Default values: '????'.
1075 .BI uid= n ", gid=" n
1076 Set the owner and group of all files.
1077 (Default: the uid and gid of the current process.)
1079 .BI dir_umask= n ", file_umask=" n ", umask=" n
1080 Set the umask used for all directories, all regular files, or all
1081 files and directories. Defaults to the umask of the current process.
1084 Select the CDROM session to mount.
1085 Defaults to leaving that decision to the CDROM driver.
1086 This option will fail with anything but a CDROM as underlying device.
1089 Select partition number n from the device.
1090 Only makes sense for CDROMS.
1091 Defaults to not parsing the partition table at all.
1094 Don't complain about invalid mount options.
1096 .SH "Mount options for hpfs"
1098 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
1099 Set the owner and group of all files. (Default: the uid and gid
1100 of the current process.)
1103 Set the umask (the bitmask of the permissions that are
1105 present). The default is the umask of the current process.
1106 The value is given in octal.
1108 .BR case=lower " / " case=asis
1109 Convert all files names to lower case, or leave them.
1113 .BR conv=binary " / " conv=text " / " conv=auto
1116 delete some random CRs (in particular, all followed by NL)
1117 when reading a file.
1120 choose more or less at random between
1121 .BR conv=binary " and " conv=text .
1124 just read what is in the file. This is the default.
1127 Do not abort mounting when certain consistency checks fail.
1129 .SH "Mount options for iso9660"
1130 ISO 9660 is a standard describing a filesystem structure to be used
1131 on CD-ROMs. (This filesystem type is also seen on some DVDs. See also the
1137 filenames appear in a 8.3 format (i.e., DOS-like restrictions on filename
1138 length), and in addition all characters are in upper case. Also there is
1139 no field for file ownership, protection, number of links, provision for
1140 block/character devices, etc.
1142 Rock Ridge is an extension to iso9660 that provides all of these unix like
1143 features. Basically there are extensions to each directory record that
1144 supply all of the additional information, and when Rock Ridge is in use,
1145 the filesystem is indistinguishable from a normal UNIX file system (except
1146 that it is read-only, of course).
1149 Disable the use of Rock Ridge extensions, even if available. Cf.\&
1153 Disable the use of Microsoft Joliet extensions, even if available. Cf.\&
1156 .BR check=r[elaxed] " / " check=s[trict]
1159 a filename is first converted to lower case before doing the lookup.
1160 This is probably only meaningful together with
1167 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
1168 Give all files in the file system the indicated user or group id,
1169 possibly overriding the information found in the Rock Ridge extensions.
1173 .BR map=n[ormal] " / " map=o[ff] " / " map=a[corn]
1174 For non-Rock Ridge volumes, normal name translation maps upper
1175 to lower case ASCII, drops a trailing `;1', and converts `;' to `.'.
1178 no name translation is done. See
1185 but also apply Acorn extensions if present.
1188 For non-Rock Ridge volumes, give all files the indicated mode.
1189 (Default: read permission for everybody.)
1190 Since Linux 2.1.37 one no longer needs to specify the mode in
1191 decimal. (Octal is indicated by a leading 0.)
1194 Also show hidden and associated files.
1195 (If the ordinary files and the associated or hidden files have
1196 the same filenames, this may make the ordinary files inaccessible.)
1198 .B block=[512|1024|2048]
1199 Set the block size to the indicated value.
1203 .BR conv=a[uto] " / " conv=b[inary] " / " conv=m[text] " / " conv=t[ext]
1206 Since Linux 1.3.54 this option has no effect anymore.
1207 (And non-binary settings used to be very dangerous,
1208 possibly leading to silent data corruption.)
1211 If the high byte of the file length contains other garbage,
1212 set this mount option to ignore the high order bits of the file length.
1213 This implies that a file cannot be larger than 16MB.
1216 Select number of session on multisession CD. (Since 2.3.4.)
1219 Session begins from sector xxx. (Since 2.3.4.)
1221 The following options are the same as for vfat and specifying them only makes
1222 sense when using discs encoded using Microsoft's Joliet extensions.
1224 .BI iocharset= value
1225 Character set to use for converting 16 bit Unicode characters on CD
1226 to 8 bit characters. The default is iso8859-1.
1229 Convert 16 bit Unicode characters on CD to UTF-8.
1231 .SH "Mount options for jfs"
1234 Character set to use for converting from Unicode to ASCII. The default is
1235 to do no conversion. Use
1237 for UTF8 translations. This requires CONFIG_NLS_UTF8 to be set in
1243 Resize the volume to
1245 blocks. JFS only supports growing a volume, not shrinking it. This option
1246 is only valid during a remount, when the volume is mounted read-write. The
1248 keyword with no value will grow the volume to the full size of the partition.
1251 Do not write to the journal. The primary use of this option is to allow
1252 for higher performance when restoring a volume from backup media. The
1253 integrity of the volume is not guaranteed if the system abnormally abends.
1256 Default. Commit metadata changes to the journal. Use this option to remount
1259 option was previously specified in order to restore normal behavior.
1261 .BR errors=continue " / " errors=remount-ro " / " errors=panic
1262 Define the behaviour when an error is encountered.
1263 (Either ignore errors and just mark the file system erroneous and continue,
1264 or remount the file system read-only, or panic and halt the system.)
1266 .BR noquota " / " quota " / " usrquota " / " grpquota
1267 These options are accepted but ignored.
1269 .SH "Mount options for minix"
1272 .SH "Mount options for msdos"
1273 See mount options for fat.
1276 file system detects an inconsistency, it reports an error and sets the file
1277 system read-only. The file system can be made writeable again by remounting
1280 .SH "Mount options for ncpfs"
1282 .IR nfs ", the " ncpfs
1283 implementation expects a binary argument (a
1284 .IR "struct ncp_mount_data" )
1285 to the mount system call. This argument is constructed by
1287 and the current version of
1289 (2.12) does not know anything about ncpfs.
1291 .SH "Mount options for nfs"
1292 Instead of a textual option string, parsed by the kernel, the
1294 file system expects a binary argument of type
1295 .IR "struct nfs_mount_data" .
1298 itself parses the following options of the form `tag=value',
1299 and puts them in the structure mentioned:
1312 .BI mounthost= name,
1320 is accepted but ignored.
1321 Also the following Boolean options, possibly preceded by
1338 Especially useful options include
1340 .B rsize=8192,wsize=8192
1341 This will make your nfs connection faster than with the default
1342 buffer size of 4096. (NFSv2 does not work with larger values of
1348 The program accessing a file on a NFS mounted file system will hang
1349 when the server crashes. The process cannot be interrupted or
1350 killed unless you also specify
1352 When the NFS server is back online the program will continue undisturbed
1353 from where it was. This is probably what you want.
1356 This option allows the kernel to time out if the nfs server is not
1357 responding for some time. The time can be
1360 This option might be useful if your nfs server sometimes doesn't respond
1361 or will be rebooted while some process tries to get a file from the server.
1362 Usually it just causes lots of trouble.
1365 Do not use locking. Do not start lockd.
1367 .SH "Mount options for ntfs"
1370 Character set to use when returning file names.
1371 Unlike VFAT, NTFS suppresses names that contain
1372 unconvertible characters. Deprecated.
1376 New name for the option earlier called
1381 Use UTF-8 for converting file names.
1383 .B uni_xlate=[0|1|2]
1384 For 0 (or `no' or `false'), do not use escape sequences
1385 for unknown Unicode characters.
1386 For 1 (or `yes' or `true') or 2, use vfat-style 4-byte escape sequences
1387 starting with ":". Here 2 give a little-endian encoding
1388 and 1 a byteswapped bigendian encoding.
1391 If enabled (posix=1), the file system distinguishes between
1392 upper and lower case. The 8.3 alias names are presented as
1393 hard links instead of being suppressed.
1395 \fBuid=\fP\fIvalue\fP, \fBgid=\fP\fIvalue\fP and \fBumask=\fP\fIvalue\fP
1396 Set the file permission on the filesystem.
1397 The umask value is given in octal.
1398 By default, the files are owned by root and not readable by somebody else.
1400 .SH "Mount options for proc"
1402 \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
1403 These options are recognized, but have no effect as far as I can see.
1405 .SH "Mount options for ramfs"
1406 Ramfs is a memory based filesystem. Mount it and you have it. Unmount it
1407 and it is gone. Present since Linux 2.3.99pre4.
1408 There are no mount options.
1410 .SH "Mount options for reiserfs"
1411 Reiserfs is a journaling filesystem.
1412 The reiserfs mount options are more fully described at
1413 .IR http://www.namesys.com/mount-options.html .
1416 Instructs version 3.6 reiserfs software to mount a version 3.5 file system,
1417 using the 3.6 format for newly created objects. This file system will no
1418 longer be compatible with reiserfs 3.5 tools.
1420 .BR hash=rupasov " / " hash=tea " / " hash=r5 " / " hash=detect
1421 Choose which hash function reiserfs will use to find files within directories.
1425 A hash invented by Yury Yu. Rupasov. It is fast and preserves locality,
1426 mapping lexicographically close file names to close hash values.
1427 This option should not be used, as it causes a high probability of hash
1431 A Davis-Meyer function implemented by Jeremy Fitzhardinge.
1432 It uses hash permuting bits in the name. It gets high randomness
1433 and, therefore, low probability of hash collisions at some CPU cost.
1434 This may be used if EHASHCOLLISION errors are experienced with the r5 hash.
1437 A modified version of the rupasov hash. It is used by default and is
1438 the best choice unless the file system has huge directories and
1439 unusual file-name patterns.
1444 to detect which hash function is in use by examining
1445 the file system being mounted, and to write this information into
1446 the reiserfs superblock. This is only useful on the first mount of
1447 an old format file system.
1450 .BR hashed_relocation
1451 Tunes the block allocator. This may provide performance improvements
1454 .BR no_unhashed_relocation
1455 Tunes the block allocator. This may provide performance improvements
1459 Disable the border allocator algorithm invented by Yury Yu. Rupasov.
1460 This may provide performance improvements in some situations.
1463 Disable journalling. This will provide slight performance improvements in
1464 some situations at the cost of losing reiserfs's fast recovery from crashes.
1465 Even with this option turned on, reiserfs still performs all journalling
1466 operations, save for actual writes into its journalling area. Implementation
1469 is a work in progress.
1472 By default, reiserfs stores small files and `file tails' directly into its
1473 tree. This confuses some utilities such as
1475 This option is used to disable packing of files into the tree.
1478 Replay the transactions which are in the journal, but do not actually
1479 mount the file system. Mainly used by
1483 A remount option which permits online expansion of reiserfs partitions.
1484 Instructs reiserfs to assume that the device has
1487 This option is designed for use with devices which are under logical
1488 volume management (LVM).
1491 utility which can be obtained from
1492 .IR ftp://ftp.namesys.com/pub/reiserfsprogs .
1494 .SH "Mount options for romfs"
1497 .SH "Mount options for smbfs"
1499 .IR nfs ", the " smbfs
1500 implementation expects a binary argument (a
1501 .IR "struct smb_mount_data" )
1502 to the mount system call. This argument is constructed by
1504 and the current version of
1506 (2.12) does not know anything about smbfs.
1508 .SH "Mount options for sysv"
1511 .SH "Mount options for tmpfs"
1512 The following parameters accept a suffix
1517 for Ki, Mi, Gi (binary kilo, mega and giga) and can be changed on remount.
1520 Override default maximum size of the filesystem.
1521 The size is given in bytes, and rounded down to entire pages.
1522 The default is half of the memory.
1525 Set number of blocks.
1528 Set number of inodes.
1531 Set initial permissions of the root directory.
1533 .SH "Mount options for udf"
1534 udf is the "Universal Disk Format" filesystem defined by the Optical
1535 Storage Technology Association, and is often used for DVD-ROM.
1540 Set the default group.
1543 Set the default umask.
1544 The value is given in octal.
1547 Set the default user.
1550 Show otherwise hidden files.
1553 Show deleted files in lists.
1556 Unset strict conformance.
1562 Set the NLS character set.
1565 Set the block size. (May not work unless 2048.)
1568 Skip volume sequence recognition.
1571 Set the CDROM session counting from 0. Default: last session.
1574 Override standard anchor location. Default: 256.
1577 Override the VolumeDesc location. (unused)
1580 Override the PartitionDesc location. (unused)
1583 Set the last block of the filesystem.
1586 Override the fileset block location. (unused)
1589 Override the root directory location. (unused)
1591 .SH "Mount options for ufs"
1594 UFS is a file system widely used in different operating systems.
1595 The problem are differences among implementations. Features of some
1596 implementations are undocumented, so its hard to recognize the
1597 type of ufs automatically.
1598 That's why the user must specify the type of ufs by mount option.
1599 Possible values are:
1603 Old format of ufs, this is the default, read only.
1604 (Don't forget to give the \-r option.)
1607 For filesystems created by a BSD-like system (NetBSD,FreeBSD,OpenBSD).
1610 For filesystems created by SunOS or Solaris on Sparc.
1613 For filesystems created by Solaris on x86.
1616 For filesystems created by HP-UX, read-only.
1619 For filesystems created by NeXTStep (on NeXT station) (currently read only).
1622 For NextStep CDROMs (block_size == 2048), read-only.
1625 For filesystems created by OpenStep (currently read only).
1626 The same filesystem type is also used by Mac OS X.
1631 Set behaviour on error:
1635 If an error is encountered, cause a kernel panic.
1637 .B [lock|umount|repair]
1638 These mount options don't do anything at present;
1639 when an error is encountered only a console message is printed.
1642 .SH "Mount options for umsdos"
1643 See mount options for msdos.
1646 option is explicitly killed by
1649 .SH "Mount options for vfat"
1650 First of all, the mount options for
1655 option is explicitly killed by
1657 Furthermore, there are
1660 Translate unhandled Unicode characters to special escaped sequences.
1661 This lets you backup and restore filenames that are created with any
1662 Unicode characters. Without this option, a '?' is used when no
1663 translation is possible. The escape character is ':' because it is
1664 otherwise illegal on the vfat filesystem. The escape sequence
1665 that gets used, where u is the unicode character,
1666 is: ':', (u & 0x3f), ((u>>6) & 0x3f), (u>>12).
1669 Allow two files with names that only differ in case.
1672 First try to make a short name without sequence number,
1677 UTF8 is the filesystem safe 8-bit encoding of Unicode that is used
1678 by the console. It can be be enabled for the filesystem with this option.
1679 If `uni_xlate' gets set, UTF8 gets disabled.
1681 .B shortname=[lower|win95|winnt|mixed]
1683 Defines the behaviour for creation and display of filenames which fit into
1684 8.3 characters. If a long name for a file exists, it will always be
1685 preferred display. There are four modes:
1689 Force the short name to lower case upon display; store a long name when
1690 the short name is not all upper case.
1693 Force the short name to upper case upon display; store a long name when
1694 the short name is not all upper case.
1697 Display the shortname as is; store a long name when the short name is
1698 not all lower case or all upper case.
1701 Display the short name as is; store a long name when the short name is not
1705 The default is "lower".
1707 .SH "Mount options for usbfs"
1709 \fBdevuid=\fP\fIuid\fP and \fBdevgid=\fP\fIgid\fP and \fBdevmode=\fP\fImode\fP
1710 Set the owner and group and mode of the device files in the usbfs file system
1711 (default: uid=gid=0, mode=0644). The mode is given in octal.
1713 \fBbusuid=\fP\fIuid\fP and \fBbusgid=\fP\fIgid\fP and \fBbusmode=\fP\fImode\fP
1714 Set the owner and group and mode of the bus directories in the usbfs
1715 file system (default: uid=gid=0, mode=0555). The mode is given in octal.
1717 \fBlistuid=\fP\fIuid\fP and \fBlistgid=\fP\fIgid\fP and \fBlistmode=\fP\fImode\fP
1718 Set the owner and group and mode of the file
1720 (default: uid=gid=0, mode=0444). The mode is given in octal.
1722 .SH "Mount options for xenix"
1725 .SH "Mount options for xfs"
1728 Sets the preferred buffered I/O size (default size is 64K).
1730 must be expressed as the logarithm (base2) of the desired I/O size.
1731 Valid values for this option are 14 through 16, inclusive
1732 (i.e. 16K, 32K, and 64K bytes).
1733 On machines with a 4K pagesize, 13 (8K bytes) is also a valid
1735 The preferred buffered I/O size can also be altered on an individual
1736 file basis using the
1741 Enable the DMAPI (Data Management API) event callouts.
1744 Set the number of in-memory log buffers.
1745 Valid numbers range from 2-8 inclusive.
1746 The default value is 8 buffers for filesystems with a blocksize of 64K,
1747 4 buffers for filesystems with a blocksize of 32K,
1748 3 buffers for filesystems with a blocksize of 16K,
1749 and 2 buffers for all other configurations.
1750 Increasing the number of buffers may increase performance on
1751 some workloads at the cost of the memory used for the
1752 additional log buffers and their associated control structures.
1755 Set the size of each in-memory log buffer.
1756 Valid sizes are 16384 (16K) and 32768 (32K).
1757 The default value for machines with more than 32MB of memory is 32768,
1758 machines with less memory use 16384 by default.
1760 \fBlogdev=\fP\fIdevice\fP and \fBrtdev=\fP\fIdevice\fP
1761 Use an external log (metadata journal) and/or real-time device.
1762 An XFS filesystem has up to three parts: a data section, a log section,
1763 and a real-time section.
1764 The real-time section is optional, and the log section can be separate
1765 from the data section or contained within it.
1770 Data allocations will not be aligned at stripe unit boundaries.
1773 Access timestamps are not updated when a file is read.
1776 The filesystem will be mounted without running log recovery.
1777 If the filesystem was not cleanly unmounted, it is likely to
1778 be inconsistent when mounted in
1781 Some files or directories may not be accessible because of this.
1784 must be mounted read-only or the mount will fail.
1787 Ignore the filesystem uuid. This avoids errors for duplicate uuids.
1790 Make writes to files opened with the O_SYNC flag set behave
1791 as if the O_DSYNC flag had been used instead.
1792 This can result in better performance without compromising
1794 However if this option is in effect, timestamp updates from
1795 O_SYNC writes can be lost if the system crashes.
1797 .BR quota " / " usrquota " / " uqnoenforce
1798 User disk quota accounting enabled, and limits (optionally) enforced.
1800 .BR grpquota " / " gqnoenforce
1801 Group disk quota accounting enabled and limits (optionally) enforced.
1803 \fBsunit=\fP\fIvalue\fP and \fBswidth=\fP\fIvalue\fP
1804 Used to specify the stripe unit and width for a RAID device or a stripe
1807 must be specified in 512-byte block units.
1808 If this option is not specified and the filesystem was made on a stripe
1809 volume or the stripe width or unit were specified for the RAID device at
1810 mkfs time, then the mount system call will restore the value from the
1812 For filesystems that are made directly on RAID devices, these options can be
1813 used to override the information in the superblock if the underlying disk
1814 layout changes after the filesystem has been created.
1817 option is required if the
1819 option has been specified,
1820 and must be a multiple of the
1824 .SH "Mount options for xiafs"
1825 None. Although nothing is wrong with xiafs, it is not used much,
1826 and is not maintained. Probably one shouldn't use it.
1827 Since Linux version 2.1.21 xiafs is no longer part of the kernel source.
1829 .SH "THE LOOP DEVICE"
1830 One further possible type is a mount via the loop device. For example,
1834 .B " mount /tmp/fdimage /mnt -t msdos -o loop=/dev/loop3,blocksize=1024"
1837 will set up the loop device
1839 to correspond to the file
1841 and then mount this device on
1844 This type of mount knows about three options, namely
1845 .BR loop ", " offset " and " encryption ,
1846 that are really options to
1848 (These options can be used in addition to those specific
1849 to the filesystem type.)
1851 If no explicit loop device is mentioned
1852 (but just an option `\fB\-o loop\fP' is given), then
1854 will try to find some unused loop device and use that.
1855 If you are not so unwise as to make
1859 then any loop device allocated by
1863 You can also free a loop device by hand, using `losetup -d', see
1868 has the following return codes (the bits can be ORed):
1874 incorrect invocation or permissions
1877 system error (out of memory, cannot fork, no more loop devices)
1891 problems writing or locking /etc/mtab
1897 some mount succeeded
1905 table of mounted file systems
1914 a list of filesystem types to try
1932 It is possible for a corrupted file system to cause a crash.
1934 Some Linux file systems don't support
1935 .B "\-o sync and \-o dirsync"
1936 (the ext2 and ext3 file systems
1938 support synchronous updates (a la BSD) when mounted with the
1944 may not be able to change mount parameters (all
1945 .IR ext2fs -specific
1948 are changeable with a remount, for example, but you can't change
1955 Mount by label or uuid will work only if your devices have the names listed in
1956 .IR /proc/partitions .
1957 In particular, it may well fail if the kernel was compiled with devfs
1958 but devfs is not mounted.
1962 command existed in Version 5 AT&T UNIX.
OSDN Git Service
