| .\" Copyright (c) 1996-2004 Andries Brouwer |
| .\" |
| .\" This page is somewhat derived from a page that was |
| .\" (c) 1980, 1989, 1991 The Regents of the University of California |
| .\" and had been heavily modified by Rik Faith and myself. |
| .\" (Probably no BSD text remains.) |
| .\" Fragments of text were written by Werner Almesberger, Remy Card, |
| .\" Stephen Tweedie and Eric Youngdale. |
| .\" |
| .\" This is free documentation; you can redistribute it and/or |
| .\" modify it under the terms of the GNU General Public License as |
| .\" published by the Free Software Foundation; either version 2 of |
| .\" the License, or (at your option) any later version. |
| .\" |
| .\" The GNU General Public License's references to "object code" |
| .\" and "executables" are to be interpreted as the output of any |
| .\" document formatting or typesetting system, including |
| .\" intermediate and printed output. |
| .\" |
| .\" This manual is distributed in the hope that it will be useful, |
| .\" but WITHOUT ANY WARRANTY; without even the implied warranty of |
| .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| .\" GNU General Public License for more details. |
| .\" |
| .\" You should have received a copy of the GNU General Public |
| .\" License along with this manual; if not, write to the Free |
| .\" Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, |
| .\" USA. |
| .\" |
| .\" 960705, aeb: version for mount-2.7g |
| .\" 970114, aeb: xiafs and ext are dead; romfs is new |
| .\" 970623, aeb: -F option |
| .\" 970914, reg: -s option |
| .\" 981111, K.Garloff: /etc/filesystems |
| .\" 990111, aeb: documented /sbin/mount.smbfs |
| .\" 990730, Yann Droneaud <lch@multimania.com>: updated page |
| .\" 991214, Elrond <Elrond@Wunder-Nett.org>: added some docs on devpts |
| .\" 010714, Michael K. Johnson <johnsonm@redhat.com> added -O |
| .\" 010725, Nikita Danilov <NikitaDanilov@Yahoo.COM>: reiserfs options |
| .\" 011124, Karl Eichwalder <ke@gnu.franken.de>: tmpfs options |
| .\" |
| .TH MOUNT 8 "2004-12-16" "Linux 2.6" "Linux Programmer's Manual" |
| .SH NAME |
| mount \- mount a file system |
| .SH SYNOPSIS |
| .BI "mount [\-lhV]" |
| .LP |
| .BI "mount \-a [\-fFnrsvw] [\-t " vfstype "] [\-O " optlist ] |
| .br |
| .BI "mount [\-fnrsvw] [\-o " options " [,...]] " "device " | " dir" |
| .br |
| .BI "mount [\-fnrsvw] [\-t " vfstype "] [\-o " options "] " "device dir" |
| .SH DESCRIPTION |
| All files accessible in a Unix system are arranged in one big |
| tree, the file hierarchy, rooted at |
| .BR / . |
| These files can be spread out over several devices. The |
| .B mount |
| command serves to attach the file system found on some device |
| to the big file tree. Conversely, the |
| .BR umount (8) |
| command will detach it again. |
| |
| The standard form of the |
| .B mount |
| command, is |
| .RS |
| .br |
| .BI "mount \-t" " type device dir" |
| .RE |
| This tells the kernel to attach the file system found on |
| .I device |
| (which is of type |
| .IR type ) |
| at the directory |
| .IR dir . |
| The previous contents (if any) and owner and mode of |
| .I dir |
| become invisible, and as long as this file system remains mounted, |
| the pathname |
| .I dir |
| refers to the root of the file system on |
| .IR device . |
| |
| Three forms of invocation do not actually mount anything: |
| .RS |
| .br |
| .B "mount \-h" |
| .RE |
| prints a help message; |
| .RS |
| .br |
| .B "mount \-V" |
| .RE |
| prints a version string; and just |
| .RS |
| .BI "mount [-l] [-t" " type" ] |
| .RE |
| lists all mounted file systems (of type |
| .IR type ). |
| The option \-l adds the (ext2, ext3 and XFS) labels in this listing. |
| See below. |
| |
| .\" In fact since 2.3.99. At first the syntax was mount -t bind. |
| Since Linux 2.4.0 it is possible to remount part of the |
| file hierarchy somewhere else. The call is |
| .RS |
| .br |
| .B "mount --bind olddir newdir" |
| .RE |
| After this call the same contents is accessible in two places. |
| One can also remount a single file (on a single file). |
| |
| This call attaches only (part of) a single filesystem, not possible |
| submounts. The entire file hierarchy including submounts is attached |
| a second place using |
| .RS |
| .br |
| .B "mount --rbind olddir newdir" |
| .RE |
| .\" available since Linux 2.4.11. |
| |
| Note that the filesystem mount options will remain the same as those |
| on the original mount point, and cannot be changed by passing the -o |
| option along with --bind/--rbind. |
| |
| Since Linux 2.5.1 it is possible to atomically move a mounted tree |
| to another place. The call is |
| .RS |
| .br |
| .B "mount --move olddir newdir" |
| .RE |
| |
| Since Linux 2.6.15 it is possible to mark a mount and its submounts as shared, |
| private, slave or unbindable. A shared mount provides ability to create mirrors |
| of that mount such that mounts and umounts within any of the mirrors propagate |
| to the other mirror. A slave mount receives propagation from its master, but |
| any not vice-versa. A private mount carries no propagation abilities. A |
| unbindable mount is a private mount which cannot cloned through a bind |
| operation. Detailed semantics is documented in Documentation/sharedsubtree.txt |
| file in the kernel source tree. |
| .RS |
| .br |
| .B "mount --make-shared mountpoint" |
| .br |
| .B "mount --make-slave mountpoint" |
| .br |
| .B "mount --make-private mountpoint" |
| .br |
| .B "mount --make-unbindable mountpoint" |
| .br |
| .RE |
| |
| The following commands allows one to recursively change the type of all the |
| mounts under a given mountpoint. |
| .RS |
| .br |
| .B "mount --make-rshared mountpoint" |
| .br |
| .B "mount --make-rslave mountpoint" |
| .br |
| .B "mount --make-rprivate mountpoint" |
| .br |
| .B |
| "mount --make-runbindable mountpoint" |
| .br |
| .RE |
| |
| The |
| .I proc |
| file system is not associated with a special device, and when |
| mounting it, an arbitrary keyword, such as |
| .I proc |
| can be used instead of a device specification. |
| (The customary choice |
| .I none |
| is less fortunate: the error message `none busy' from |
| .B umount |
| can be confusing.) |
| |
| Most devices are indicated by a file name (of a block special device), like |
| .IR /dev/sda1 , |
| but there are other possibilities. For example, in the case of an NFS mount, |
| .I device |
| may look like |
| .IR knuth.cwi.nl:/dir . |
| It is possible to indicate a block special device using its |
| volume label or UUID (see the \-L and \-U options below). |
| |
| The file |
| .I /etc/fstab |
| (see |
| .BR fstab (5)), |
| may contain lines describing what devices are usually |
| mounted where, using which options. This file is used in three ways: |
| .LP |
| (i) The command |
| .RS |
| .br |
| .BI "mount \-a [\-t " type "] [\-O " optlist ] |
| .RE |
| (usually given in a bootscript) causes all file systems mentioned in |
| .I fstab |
| (of the proper type and/or having or not having the proper options) |
| to be mounted as indicated, except for those whose line contains the |
| .B noauto |
| keyword. Adding the |
| .B \-F |
| option will make mount fork, so that the |
| filesystems are mounted simultaneously. |
| .LP |
| (ii) When mounting a file system mentioned in |
| .IR fstab , |
| it suffices to give only the device, or only the mount point. |
| .LP |
| (iii) Normally, only the superuser can mount file systems. |
| However, when |
| .I fstab |
| contains the |
| .B user |
| option on a line, anybody can mount the corresponding system. |
| .LP |
| Thus, given a line |
| .RS |
| .br |
| .B "/dev/cdrom /cd iso9660 ro,user,noauto,unhide" |
| .RE |
| any user can mount the iso9660 file system found on his CDROM |
| using the command |
| .RS |
| .br |
| .B "mount /dev/cdrom" |
| .RE |
| or |
| .RS |
| .br |
| .B "mount /cd" |
| .RE |
| For more details, see |
| .BR fstab (5). |
| Only the user that mounted a filesystem can unmount it again. |
| If any user should be able to unmount, then use |
| .B users |
| instead of |
| .B user |
| in the |
| .I fstab |
| line. |
| The |
| .B owner |
| option is similar to the |
| .B user |
| option, with the restriction that the user must be the owner |
| of the special file. This may be useful e.g. for |
| .I /dev/fd |
| if a login script makes the console user owner of this device. |
| The |
| .B group |
| option is similar, with the restriction that the user must be |
| member of the group of the special file. |
| |
| The programs |
| .B mount |
| and |
| .B umount |
| maintain a list of currently mounted file systems in the file |
| .IR /etc/mtab . |
| If no arguments are given to |
| .BR mount , |
| this list is printed. |
| |
| When the |
| .I proc |
| filesystem is mounted (say at |
| .IR /proc ), |
| the files |
| .I /etc/mtab |
| and |
| .I /proc/mounts |
| have very similar contents. The former has somewhat |
| more information, such as the mount options used, |
| but is not necessarily up-to-date (cf. the |
| .B \-n |
| option below). It is possible to replace |
| .I /etc/mtab |
| by a symbolic link to |
| .IR /proc/mounts , |
| and especially when you have very large numbers of mounts |
| things will be much faster with that symlink, |
| but some information is lost that way, and in particular |
| working with the loop device will be less convenient, |
| and using the "user" option will fail. |
| |
| .SH OPTIONS |
| The full set of options used by an invocation of |
| .B mount |
| is determined by first extracting the |
| options for the file system from the |
| .I fstab |
| table, then applying any options specified by the |
| .B \-o |
| argument, and finally applying a |
| .BR \-r " or " \-w |
| option, when present. |
| |
| Options available for the |
| .B mount |
| command: |
| .TP |
| .B \-V |
| Output version. |
| .TP |
| .B \-h |
| Print a help message. |
| .TP |
| .B \-v |
| Verbose mode. |
| .TP |
| .B \-a |
| Mount all filesystems (of the given types) mentioned in |
| .IR fstab . |
| .TP |
| .B \-F |
| (Used in conjunction with |
| .BR \-a .) |
| Fork off a new incarnation of mount for each device. |
| This will do the mounts on different devices or different NFS servers |
| in parallel. |
| This has the advantage that it is faster; also NFS timeouts go in |
| parallel. A disadvantage is that the mounts are done in undefined order. |
| Thus, you cannot use this option if you want to mount both |
| .I /usr |
| and |
| .IR /usr/spool . |
| .TP |
| .B \-f |
| Causes everything to be done except for the actual system call; if it's not |
| obvious, this ``fakes'' mounting the file system. This option is useful in |
| conjunction with the |
| .B \-v |
| flag to determine what the |
| .B mount |
| command is trying to do. It can also be used to add entries for devices |
| that were mounted earlier with the -n option. The -f option checks for |
| existing record in /etc/mtab and fails when the record already |
| exists (with regular non-fake mount, this check is done by kernel). |
| .TP |
| .B \-i |
| Don't call the /sbin/mount.<filesystem> helper even if it exists. |
| .TP |
| .B \-l |
| Add the ext2, ext3 and XFS labels in the mount output. Mount must have |
| permission to read the disk device (e.g. be suid root) for this to work. |
| One can set such a label for ext2 or ext3 using the |
| .BR e2label (8) |
| utility, or for XFS using |
| .BR xfs_admin (8), |
| or for reiserfs using |
| .BR reiserfstune (8). |
| .TP |
| .B \-n |
| Mount without writing in |
| .IR /etc/mtab . |
| This is necessary for example when |
| .I /etc |
| is on a read-only file system. |
| .TP |
| .BI \-p " num" |
| In case of a loop mount with encryption, read the passphrase from |
| file descriptor |
| .I num |
| instead of from the terminal. |
| .TP |
| .B \-s |
| Tolerate sloppy mount options rather than failing. This will ignore |
| mount options not supported by a filesystem type. Not all filesystems |
| support this option. This option exists for support of the Linux |
| autofs\-based automounter. |
| .TP |
| .B \-r |
| Mount the file system read-only. A synonym is |
| .BR "\-o ro" . |
| .TP |
| .B \-w |
| Mount the file system read/write. This is the default. A synonym is |
| .BR "\-o rw" . |
| .TP |
| .BI \-L " label" |
| Mount the partition that has the specified |
| .IR label . |
| .TP |
| .BI \-U " uuid" |
| Mount the partition that has the specified |
| .IR uuid . |
| These two options require the file |
| .I /proc/partitions |
| (present since Linux 2.1.116) to exist. |
| .TP |
| .BI \-t " vfstype" |
| The argument following the |
| .B \-t |
| is used to indicate the file system type. The file system types which are |
| currently supported include: |
| .IR adfs , |
| .IR affs , |
| .IR autofs , |
| .IR cifs , |
| .IR coda , |
| .IR coherent , |
| .IR cramfs , |
| .IR debugfs , |
| .IR devpts , |
| .IR efs , |
| .IR ext , |
| .IR ext2 , |
| .IR ext3 , |
| .IR hfs , |
| .IR hfsplus , |
| .IR hpfs , |
| .IR iso9660 , |
| .IR jfs , |
| .IR minix , |
| .IR msdos , |
| .IR ncpfs , |
| .IR nfs , |
| .IR nfs4 , |
| .IR ntfs , |
| .IR proc , |
| .IR qnx4 , |
| .IR ramfs , |
| .IR reiserfs , |
| .IR romfs , |
| .IR smbfs , |
| .IR sysv , |
| .IR tmpfs , |
| .IR udf , |
| .IR ufs , |
| .IR umsdos , |
| .IR usbfs , |
| .IR vfat , |
| .IR xenix , |
| .IR xfs , |
| .IR xiafs . |
| Note that coherent, sysv and xenix are equivalent and that |
| .I xenix |
| and |
| .I coherent |
| will be removed at some point in the future \(em use |
| .I sysv |
| instead. Since kernel version 2.1.21 the types |
| .I ext |
| and |
| .I xiafs |
| do not exist anymore. Earlier, |
| .I usbfs |
| was known as |
| .IR usbdevfs . |
| Note, the real list of all supported filesystems depends on your |
| kernel. |
| |
| For most types all the |
| .B mount |
| program has to do is issue a simple |
| .IR mount (2) |
| system call, and no detailed knowledge of the filesystem type is required. |
| For a few types however (like nfs, nfs4, cifs, smbfs, ncpfs) ad hoc code is |
| necessary. The nfs, nfs4, cifs, smbfs, and ncpfs |
| have a separate mount program. In order to make it possible to |
| treat all types in a uniform way, mount will execute the program |
| .I /sbin/mount.TYPE |
| (if that exists) when called with type |
| .IR TYPE . |
| Since various versions of the |
| .I smbmount |
| program have different calling conventions, |
| .I /sbin/mount.smbfs |
| may have to be a shell script that sets up the desired call. |
| |
| If no |
| .B \-t |
| option is given, or if the |
| .B auto |
| type is specified, mount will try to guess the desired type. |
| Mount uses the blkid or volume_id library for guessing the filesystem |
| type; if that does not turn up anything that looks familiar, |
| mount will try to read the file |
| .IR /etc/filesystems , |
| or, if that does not exist, |
| .IR /proc/filesystems . |
| All of the filesystem types listed there will be tried, |
| except for those that are labeled "nodev" (e.g., |
| .IR devpts , |
| .I proc |
| and |
| .IR nfs ). |
| If |
| .I /etc/filesystems |
| ends in a line with a single * only, mount will read |
| .I /proc/filesystems |
| afterwards. |
| |
| The |
| .B auto |
| type may be useful for user-mounted floppies. |
| Creating a file |
| .I /etc/filesystems |
| can be useful to change the probe order (e.g., to try vfat before msdos |
| or ext3 before ext2) or if you use a kernel module autoloader. |
| Warning: the probing uses a heuristic (the presence of appropriate `magic'), |
| and could recognize the wrong filesystem type, possibly with catastrophic |
| consequences. If your data is valuable, don't ask |
| .B mount |
| to guess. |
| |
| More than one type may be specified in a comma separated |
| list. The list of file system types can be prefixed with |
| .B no |
| to specify the file system types on which no action should be taken. |
| (This can be meaningful with the |
| .B \-a |
| option.) |
| |
| For example, the command: |
| .RS |
| .RS |
| .B "mount \-a \-t nomsdos,ext" |
| .RE |
| mounts all file systems except those of type |
| .I msdos |
| and |
| .IR ext . |
| .RE |
| .TP |
| .B \-O |
| Used in conjunction with |
| .BR \-a , |
| to limit the set of filesystems to which the |
| .B \-a |
| is applied. Like |
| .B \-t |
| in this regard except that it is useless except in the context of |
| .BR \-a . |
| For example, the command: |
| .RS |
| .RS |
| .B "mount \-a \-O no_netdev" |
| .RE |
| mounts all file systems except those which have the option |
| .I _netdev |
| specified in the options field in the |
| .I /etc/fstab |
| file. |
| |
| It is different from |
| .B \-t |
| in that each option is matched exactly; a leading |
| .B no |
| at the beginning of one option does not negate the rest. |
| |
| The |
| .B \-t |
| and |
| .B \-O |
| options are cumulative in effect; that is, the command |
| .RS |
| .B "mount \-a \-t ext2 \-O _netdev" |
| .RE |
| mounts all ext2 filesystems with the _netdev option, not all filesystems |
| that are either ext2 or have the _netdev option specified. |
| .RE |
| .TP |
| .B \-o |
| Options are specified with a |
| .B \-o |
| flag followed by a comma separated string of options. |
| Some of these options are only useful when they appear in the |
| .I /etc/fstab |
| file. The following options apply to any file system that is being |
| mounted (but not every file system actually honors them - e.g., the |
| .B sync |
| option today has effect only for ext2, ext3, fat, vfat and ufs): |
| .RS |
| .TP |
| .B async |
| All I/O to the file system should be done asynchronously. |
| .TP |
| .B atime |
| Update inode access time for each access. This is the default. |
| .TP |
| .B auto |
| Can be mounted with the |
| .B \-a |
| option. |
| .TP |
| .B defaults |
| Use default options: |
| .BR rw ", " suid ", " dev ", " exec ", " auto ", " nouser ", and " async. |
| .TP |
| .B dev |
| Interpret character or block special devices on the file system. |
| .TP |
| .B exec |
| Permit execution of binaries. |
| .TP |
| .B group |
| Allow an ordinary (i.e., non-root) user to mount the file system if one |
| of his groups matches the group of the device. |
| This option implies the options |
| .BR nosuid " and " nodev |
| (unless overridden by subsequent options, as in the option line |
| .BR group,dev,suid ). |
| .TP |
| .B mand |
| Allow mandatory locks on this filesystem. See |
| .BR fcntl (2). |
| .TP |
| .B _netdev |
| The filesystem resides on a device that requires network access |
| (used to prevent the system from attempting to mount these filesystems |
| until the network has been enabled on the system). |
| .TP |
| .B noatime |
| Do not update inode access times on this file system (e.g, for faster |
| access on the news spool to speed up news servers). |
| .TP |
| .B nodiratime |
| Do not update directory inode access times on this filesystem. |
| .TP |
| .B relatime |
| Update inode access times relative to modify or change time. Access |
| time is only updated if the previous access time was earlier than the |
| current modify or change time. (Similar to noatime, but doesn't break |
| mutt or other applications that need to know if a file has been read |
| since the last time it was modified.) |
| .TP |
| .B noauto |
| Can only be mounted explicitly (i.e., the |
| .B \-a |
| option will not cause the file system to be mounted). |
| .TP |
| .B nodev |
| Do not interpret character or block special devices on the file |
| system. |
| .TP |
| .B noexec |
| Do not allow direct execution of any binaries on the mounted file system. |
| (Until recently it was possible to run binaries anyway using a command like |
| /lib/ld*.so /mnt/binary. This trick fails since Linux 2.4.25 / 2.6.0.) |
| .TP |
| .B nomand |
| Do not allow mandatory locks on this filesystem. |
| .TP |
| .B nosuid |
| Do not allow set-user-identifier or set-group-identifier bits to take |
| effect. (This seems safe, but is in fact rather unsafe if you have |
| suidperl(1) installed.) |
| .TP |
| .B nouser |
| Forbid an ordinary (i.e., non-root) user to mount the file system. |
| This is the default. |
| .TP |
| .B owner |
| Allow an ordinary (i.e., non-root) user to mount the file system if he |
| is the owner of the device. |
| This option implies the options |
| .BR nosuid " and " nodev |
| (unless overridden by subsequent options, as in the option line |
| .BR owner,dev,suid ). |
| .TP |
| .B remount |
| Attempt to remount an already-mounted file system. This is commonly |
| used to change the mount flags for a file system, especially to make a |
| readonly file system writeable. It does not change device or mount point. |
| .TP |
| .B ro |
| Mount the file system read-only. |
| .TP |
| .B rw |
| Mount the file system read-write. |
| .TP |
| .B suid |
| Allow set-user-identifier or set-group-identifier bits to take |
| effect. |
| .TP |
| .B sync |
| All I/O to the file system should be done synchronously. In case of media with limited number of write cycles |
| (e.g. some flash drives) "sync" may cause life-cycle shortening. |
| .TP |
| .B dirsync |
| All directory updates within the file system should be done synchronously. |
| This affects the following system calls: creat, link, unlink, symlink, |
| mkdir, rmdir, mknod and rename. |
| .TP |
| .B user |
| Allow an ordinary user to mount the file system. |
| The name of the mounting user is written to mtab so that he can unmount |
| the file system again. |
| This option implies the options |
| .BR noexec ", " nosuid ", and " nodev |
| (unless overridden by subsequent options, as in the option line |
| .BR user,exec,dev,suid ). |
| .TP |
| .B users |
| Allow every user to mount and unmount the file system. |
| This option implies the options |
| .BR noexec ", " nosuid ", and " nodev |
| (unless overridden by subsequent options, as in the option line |
| .BR users,exec,dev,suid ). |
| .TP |
| \fBcontext=\fP\fIcontext\fP, \fBfscontext=\fP\fIcontext\fP and \fBdefcontext=\fP\fIcontext\fP |
| The |
| .BR context= |
| option is useful when mounting filesystems that do not support |
| extended attributes, such as a floppy or hard disk formatted with VFAT, or |
| systems that are not normally running under SELinux, such as an ext3 formatted |
| disk from a non-SELinux workstation. You can also use |
| .BR context= |
| on filesystems you do not trust, such as a floppy. It also helps in compatibility with |
| xattr-supporting filesystems on earlier 2.4.<x> kernel versions. Even where |
| xattrs are supported, you can save time not having to label every file by |
| assigning the entire disk one security context. |
| |
| A commonly used option for removable media is |
| .BR context=system_u:object_r:removable_t . |
| |
| Two other options are |
| .BR fscontext= |
| and |
| .BR defcontext= , |
| both of which are mutually exclusive of the context option. This means you |
| can use fscontext and defcontext with each other, but neither can be used with |
| context. |
| |
| The |
| .BR fscontext= |
| option works for all filesystems, regardless of their xattr |
| support. The fscontext option sets the overarching filesystem label to a |
| specific security context. This filesystem label is separate from the |
| individual labels on the files. It represents the entire filesystem for |
| certain kinds of permission checks, such as during mount or file creation. |
| Individual file labels are still obtained from the xattrs on the files |
| themselves. The context option actually sets the aggregate context that |
| fscontext provides, in addition to supplying the same label for individual |
| files. |
| |
| You can set the default security context for unlabeled files using |
| .BR defcontext= |
| option. This overrides the value set for unlabeled files in the policy and requires a |
| file system that supports xattr labeling. |
| |
| For more details see |
| .BR selinux (8) |
| .RE |
| .TP |
| .B \-\-bind |
| Remount a subtree somewhere else (so that its contents are available |
| in both places). See above. |
| .TP |
| .B \-\-move |
| Move a subtree to some other place. See above. |
| |
| .SH "FILESYSTEM SPECIFIC MOUNT OPTIONS" |
| The following options apply only to certain file systems. |
| We sort them by file system. They all follow the |
| .B \-o |
| flag. |
| |
| What options are supported depends a bit on the running kernel. |
| More info may be found in the kernel source subdirectory |
| .IR Documentation/filesystems . |
| |
| .SH "Mount options for adfs" |
| .TP |
| \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP |
| Set the owner and group of the files in the file system (default: uid=gid=0). |
| .TP |
| \fBownmask=\fP\fIvalue\fP and \fBothmask=\fP\fIvalue\fP |
| Set the permission mask for ADFS 'owner' permissions and 'other' permissions, |
| respectively (default: 0700 and 0077, respectively). |
| See also |
| .IR /usr/src/linux/Documentation/filesystems/adfs.txt . |
| .SH "Mount options for affs" |
| .TP |
| \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP |
| Set the owner and group of the root of the file system (default: uid=gid=0, |
| but with option |
| .B uid |
| or |
| .B gid |
| without specified value, the uid and gid of the current process are taken). |
| .TP |
| \fBsetuid=\fP\fIvalue\fP and \fBsetgid=\fP\fIvalue\fP |
| Set the owner and group of all files. |
| .TP |
| .BI mode= value |
| Set the mode of all files to |
| .IR value " & 0777" |
| disregarding the original permissions. |
| Add search permission to directories that have read permission. |
| The value is given in octal. |
| .TP |
| .B protect |
| Do not allow any changes to the protection bits on the file system. |
| .TP |
| .B usemp |
| Set uid and gid of the root of the file system to the uid and gid |
| of the mount point upon the first sync or umount, and then |
| clear this option. Strange... |
| .TP |
| .B verbose |
| Print an informational message for each successful mount. |
| .TP |
| .BI prefix= string |
| Prefix used before volume name, when following a link. |
| .TP |
| .BI volume= string |
| Prefix (of length at most 30) used before '/' when following a symbolic link. |
| .TP |
| .BI reserved= value |
| (Default: 2.) Number of unused blocks at the start of the device. |
| .TP |
| .BI root= value |
| Give explicitly the location of the root block. |
| .TP |
| .BI bs= value |
| Give blocksize. Allowed values are 512, 1024, 2048, 4096. |
| .TP |
| .BR grpquota " / " noquota " / " quota " / " usrquota |
| These options are accepted but ignored. |
| (However, quota utilities may react to such strings in |
| .IR /etc/fstab .) |
| |
| .SH "Mount options for cifs" |
| See the options section of the |
| .BR mount.cifs (8) |
| man page (cifs-mount package must be installed). |
| |
| .SH "Mount options for coherent" |
| None. |
| |
| .SH "Mount options for debugfs" |
| The debugfs file system is a pseudo file system, traditionally mounted on |
| .IR /sys/kernel/debug . |
| .\" or just /debug |
| .\" present since 2.6.11 |
| There are no mount options. |
| |
| .SH "Mount options for devpts" |
| The devpts file system is a pseudo file system, traditionally mounted on |
| .IR /dev/pts . |
| In order to acquire a pseudo terminal, a process opens |
| .IR /dev/ptmx ; |
| the number of the pseudo terminal is then made available to the process |
| and the pseudo terminal slave can be accessed as |
| .IR /dev/pts/ <number>. |
| .TP |
| \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP |
| This sets the owner or the group of newly created PTYs to |
| the specified values. When nothing is specified, they will |
| be set to the UID and GID of the creating process. |
| For example, if there is a tty group with GID 5, then |
| .B gid=5 |
| will cause newly created PTYs to belong to the tty group. |
| .TP |
| .BI mode= value |
| Set the mode of newly created PTYs to the specified value. |
| The default is 0600. |
| A value of |
| .B mode=620 |
| and |
| .B gid=5 |
| makes "mesg y" the default on newly created PTYs. |
| |
| .SH "Mount options for ext" |
| None. |
| Note that the `ext' file system is obsolete. Don't use it. |
| Since Linux version 2.1.21 extfs is no longer part of the kernel source. |
| |
| .SH "Mount options for ext2" |
| The `ext2' file system is the standard Linux file system. |
| .\" Due to a kernel bug, it may be mounted with random mount options |
| .\" (fixed in Linux 2.0.4). |
| Since Linux 2.5.46, for most mount options the default |
| is determined by the filesystem superblock. Set them with |
| .BR tune2fs (8). |
| .TP |
| .BR acl " / " noacl |
| Support POSIX Access Control Lists (or not). |
| .\" requires CONFIG_EXT2_FS_POSIX_ACL |
| .TP |
| .BR bsddf " / " minixdf |
| Set the behaviour for the |
| .I statfs |
| system call. The |
| .B minixdf |
| behaviour is to return in the |
| .I f_blocks |
| field the total number of blocks of the file system, while the |
| .B bsddf |
| behaviour (which is the default) is to subtract the overhead blocks |
| used by the ext2 file system and not available for file storage. Thus |
| .RE |
| .nf |
| |
| % mount /k -o minixdf; df /k; umount /k |
| Filesystem 1024-blocks Used Available Capacity Mounted on |
| /dev/sda6 2630655 86954 2412169 3% /k |
| % mount /k -o bsddf; df /k; umount /k |
| Filesystem 1024-blocks Used Available Capacity Mounted on |
| /dev/sda6 2543714 13 2412169 0% /k |
| |
| .fi |
| (Note that this example shows that one can add command line options |
| to the options given in |
| .IR /etc/fstab .) |
| |
| .TP |
| .BR check=none " / " nocheck |
| No checking is done at mount time. This is the default. This is fast. |
| It is wise to invoke |
| .BR e2fsck (8) |
| every now and then, e.g. at boot time. |
| .TP |
| .B debug |
| Print debugging info upon each (re)mount. |
| .TP |
| .BR errors=continue " / " errors=remount-ro " / " errors=panic |
| Define the behaviour when an error is encountered. |
| (Either ignore errors and just mark the file system erroneous and continue, |
| or remount the file system read-only, or panic and halt the system.) |
| The default is set in the filesystem superblock, and can be |
| changed using |
| .BR tune2fs (8). |
| .TP |
| .BR grpid " or " bsdgroups " / " nogrpid " or " sysvgroups |
| These options define what group id a newly created file gets. |
| When |
| .BR grpid |
| is set, it takes the group id of the directory in which it is created; |
| otherwise (the default) it takes the fsgid of the current process, unless |
| the directory has the setgid bit set, in which case it takes the gid |
| from the parent directory, and also gets the setgid bit set |
| if it is a directory itself. |
| .TP |
| .BR grpquota " / " noquota " / " quota " / " usrquota |
| These options are accepted but ignored. |
| .TP |
| .BR nobh |
| Do not attach buffer_heads to file pagecache. (Since 2.5.49.) |
| .TP |
| .BR nouid32 |
| Disables 32-bit UIDs and GIDs. This is for interoperability with older |
| kernels which only store and expect 16-bit values. |
| .TP |
| .BR oldalloc " or " orlov |
| Use old allocator or Orlov allocator for new inodes. Orlov is default. |
| .TP |
| \fBresgid=\fP\fIn\fP and \fBresuid=\fP\fIn\fP |
| The ext2 file system reserves a certain percentage of the available |
| space (by default 5%, see |
| .BR mke2fs (8) |
| and |
| .BR tune2fs (8)). |
| These options determine who can use the reserved blocks. |
| (Roughly: whoever has the specified uid, or belongs to the specified group.) |
| .TP |
| .BI sb= n |
| Instead of block 1, use block |
| .I n |
| as superblock. This could be useful when the filesystem has been damaged. |
| (Earlier, copies of the superblock would be made every 8192 blocks: in |
| block 1, 8193, 16385, ... (and one got thousands of copies on |
| a big filesystem). Since version 1.08, |
| .B mke2fs |
| has a \-s (sparse superblock) option to reduce the number of backup |
| superblocks, and since version 1.15 this is the default. Note |
| that this may mean that ext2 filesystems created by a recent |
| .B mke2fs |
| cannot be mounted r/w under Linux 2.0.*.) |
| The block number here uses 1k units. Thus, if you want to use logical |
| block 32768 on a filesystem with 4k blocks, use "sb=131072". |
| .TP |
| .BR user_xattr " / " nouser_xattr |
| Support "user." extended attributes (or not). |
| .\" requires CONFIG_EXT2_FS_XATTR |
| |
| |
| .SH "Mount options for ext3" |
| The `ext3' file system is a version of the ext2 file system which has been |
| enhanced with journalling. It supports the same options as ext2 as |
| well as the following additions: |
| .\" .TP |
| .\" .BR abort |
| .\" Mount the file system in abort mode, as if a fatal error has occurred. |
| .TP |
| .BR journal=update |
| Update the ext3 file system's journal to the current format. |
| .TP |
| .BR journal=inum |
| When a journal already exists, this option is ignored. Otherwise, it |
| specifies the number of the inode which will represent the ext3 file system's |
| journal file; ext3 will create a new journal, overwriting the old contents |
| of the file whose inode number is |
| .IR inum . |
| .TP |
| .BR noload |
| Do not load the ext3 file system's journal on mounting. |
| .TP |
| .BR data=journal " / " data=ordered " / " data=writeback |
| Specifies the journalling mode for file data. Metadata is always journaled. |
| To use modes other than |
| .B ordered |
| on the root file system, pass the mode to the kernel as boot parameter, e.g. |
| .IR rootflags=data=journal . |
| .RS |
| .TP |
| .B journal |
| All data is committed into the journal prior to being written into the |
| main file system. |
| .TP |
| .B ordered |
| This is the default mode. All data is forced directly out to the main file |
| system prior to its metadata being committed to the journal. |
| .TP |
| .B writeback |
| Data ordering is not preserved - data may be written into the main |
| file system after its metadata has been committed to the journal. |
| This is rumoured to be the highest-throughput option. It guarantees |
| internal file system integrity, however it can allow old data to appear |
| in files after a crash and journal recovery. |
| .RE |
| .TP |
| .BI commit= nrsec |
| Sync all data and metadata every |
| .I nrsec |
| seconds. The default value is 5 seconds. Zero means default. |
| .RE |
| .TP |
| .BR user_xattr |
| Enable Extended User Attributes. See the |
| .BR attr (5) |
| manual page. |
| .TP |
| .BR acl |
| Enable POSIX Access Control Lists. See the |
| .BR acl (5) |
| manual page. |
| |
| .SH "Mount options for fat" |
| (Note: |
| .I fat |
| is not a separate filesystem, but a common part of the |
| .IR msdos , |
| .I umsdos |
| and |
| .I vfat |
| filesystems.) |
| .TP |
| .BR blocksize=512 " / " blocksize=1024 " / " blocksize=2048 |
| Set blocksize (default 512). |
| .TP |
| \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP |
| Set the owner and group of all files. |
| (Default: the uid and gid of the current process.) |
| .TP |
| .BI umask= value |
| Set the umask (the bitmask of the permissions that are |
| .B not |
| present). The default is the umask of the current process. |
| The value is given in octal. |
| .TP |
| .BI dmask= value |
| Set the umask applied to directories only. |
| The default is the umask of the current process. |
| The value is given in octal. |
| .\" Present since Linux 2.5.43. |
| .TP |
| .BI fmask= value |
| Set the umask applied to regular files only. |
| The default is the umask of the current process. |
| The value is given in octal. |
| .\" Present since Linux 2.5.43. |
| .TP |
| .BI check= value |
| Three different levels of pickyness can be chosen: |
| .RS |
| .TP |
| .B r[elaxed] |
| Upper and lower case are accepted and equivalent, long name parts are |
| truncated (e.g. |
| .I verylongname.foobar |
| becomes |
| .IR verylong.foo ), |
| leading and embedded spaces are accepted in each name part (name and extension). |
| .TP |
| .B n[ormal] |
| Like "relaxed", but many special characters (*, ?, <, spaces, etc.) are |
| rejected. This is the default. |
| .TP |
| .B s[trict] |
| Like "normal", but names may not contain long parts and special characters |
| that are sometimes used on Linux, but are not accepted by MS-DOS are |
| rejected. (+, =, spaces, etc.) |
| .RE |
| .TP |
| .BI codepage= value |
| Sets the codepage for converting to shortname characters on FAT |
| and VFAT filesystems. By default, codepage 437 is used. |
| .TP |
| .BR conv=b[inary] " / " conv=t[ext] " / " conv=a[uto] |
| The |
| .I fat |
| file system can perform CRLF<-->NL (MS-DOS text format to UNIX text |
| format) conversion in the kernel. The following conversion modes are |
| available: |
| .RS |
| .TP |
| .B binary |
| no translation is performed. This is the default. |
| .TP |
| .B text |
| CRLF<-->NL translation is performed on all files. |
| .TP |
| .B auto |
| CRLF<-->NL translation is performed on all files that don't have a |
| "well-known binary" extension. The list of known extensions can be found at |
| the beginning of |
| .I fs/fat/misc.c |
| (as of 2.0, the list is: exe, com, bin, app, sys, drv, ovl, ovr, obj, |
| lib, dll, pif, arc, zip, lha, lzh, zoo, tar, z, arj, tz, taz, tzp, tpz, |
| gz, tgz, deb, gif, bmp, tif, gl, jpg, pcx, tfm, vf, gf, pk, pxl, dvi). |
| .PP |
| Programs that do computed lseeks won't like in-kernel text conversion. |
| Several people have had their data ruined by this translation. Beware! |
| |
| For file systems mounted in binary mode, a conversion tool |
| (fromdos/todos) is available. |
| .RE |
| .TP |
| .BI cvf_format= module |
| Forces the driver to use the CVF (Compressed Volume File) module |
| .RI cvf_ module |
| instead of auto-detection. If the kernel supports kmod, the |
| cvf_format=xxx option also controls on-demand CVF module loading. |
| .TP |
| .BI cvf_option= option |
| Option passed to the CVF module. |
| .TP |
| .B debug |
| Turn on the |
| .I debug |
| flag. A version string and a list of file system parameters will be |
| printed (these data are also printed if the parameters appear to be |
| inconsistent). |
| .TP |
| .BR fat=12 " / " fat=16 " / " fat=32 |
| Specify a 12, 16 or 32 bit fat. This overrides |
| the automatic FAT type detection routine. Use with caution! |
| .TP |
| .BI iocharset= value |
| Character set to use for converting between 8 bit characters |
| and 16 bit Unicode characters. The default is iso8859-1. |
| Long filenames are stored on disk in Unicode format. |
| .TP |
| .B quiet |
| Turn on the |
| .I quiet |
| flag. Attempts to chown or chmod files do not return errors, |
| although they fail. Use with caution! |
| .TP |
| .B "sys_immutable, showexec, dots, nodots, dotsOK=[yes|no]" |
| Various misguided attempts to force Unix or DOS conventions |
| onto a FAT file system. |
| |
| .SH "Mount options for hfs" |
| .TP |
| .BI creator= cccc ", type=" cccc |
| Set the creator/type values as shown by the MacOS finder |
| used for creating new files. Default values: '????'. |
| .TP |
| .BI uid= n ", gid=" n |
| Set the owner and group of all files. |
| (Default: the uid and gid of the current process.) |
| .TP |
| .BI dir_umask= n ", file_umask=" n ", umask=" n |
| Set the umask used for all directories, all regular files, or all |
| files and directories. Defaults to the umask of the current process. |
| .TP |
| .BI session= n |
| Select the CDROM session to mount. |
| Defaults to leaving that decision to the CDROM driver. |
| This option will fail with anything but a CDROM as underlying device. |
| .TP |
| .BI part= n |
| Select partition number n from the device. |
| Only makes sense for CDROMS. |
| Defaults to not parsing the partition table at all. |
| .TP |
| .B quiet |
| Don't complain about invalid mount options. |
| |
| .SH "Mount options for hpfs" |
| .TP |
| \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP |
| Set the owner and group of all files. (Default: the uid and gid |
| of the current process.) |
| .TP |
| .BI umask= value |
| Set the umask (the bitmask of the permissions that are |
| .B not |
| present). The default is the umask of the current process. |
| The value is given in octal. |
| .TP |
| .BR case=lower " / " case=asis |
| Convert all files names to lower case, or leave them. |
| (Default: |
| .BR case=lower .) |
| .TP |
| .BR conv=binary " / " conv=text " / " conv=auto |
| For |
| .BR conv=text , |
| delete some random CRs (in particular, all followed by NL) |
| when reading a file. |
| For |
| .BR conv=auto , |
| choose more or less at random between |
| .BR conv=binary " and " conv=text . |
| For |
| .BR conv=binary , |
| just read what is in the file. This is the default. |
| .TP |
| .B nocheck |
| Do not abort mounting when certain consistency checks fail. |
| |
| .SH "Mount options for iso9660" |
| ISO 9660 is a standard describing a filesystem structure to be used |
| on CD-ROMs. (This filesystem type is also seen on some DVDs. See also the |
| .I udf |
| filesystem.) |
| |
| Normal |
| .I iso9660 |
| filenames appear in a 8.3 format (i.e., DOS-like restrictions on filename |
| length), and in addition all characters are in upper case. Also there is |
| no field for file ownership, protection, number of links, provision for |
| block/character devices, etc. |
| |
| Rock Ridge is an extension to iso9660 that provides all of these unix like |
| features. Basically there are extensions to each directory record that |
| supply all of the additional information, and when Rock Ridge is in use, |
| the filesystem is indistinguishable from a normal UNIX file system (except |
| that it is read-only, of course). |
| .TP |
| .B norock |
| Disable the use of Rock Ridge extensions, even if available. Cf.\& |
| .BR map . |
| .TP |
| .B nojoliet |
| Disable the use of Microsoft Joliet extensions, even if available. Cf.\& |
| .BR map . |
| .TP |
| .BR check=r[elaxed] " / " check=s[trict] |
| With |
| .BR check=relaxed , |
| a filename is first converted to lower case before doing the lookup. |
| This is probably only meaningful together with |
| .B norock |
| and |
| .BR map=normal . |
| (Default: |
| .BR check=strict .) |
| .TP |
| \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP |
| Give all files in the file system the indicated user or group id, |
| possibly overriding the information found in the Rock Ridge extensions. |
| (Default: |
| .BR uid=0,gid=0 .) |
| .TP |
| .BR map=n[ormal] " / " map=o[ff] " / " map=a[corn] |
| For non-Rock Ridge volumes, normal name translation maps upper |
| to lower case ASCII, drops a trailing `;1', and converts `;' to `.'. |
| With |
| .B map=off |
| no name translation is done. See |
| .BR norock . |
| (Default: |
| .BR map=normal .) |
| .B map=acorn |
| is like |
| .BR map=normal |
| but also apply Acorn extensions if present. |
| .TP |
| .BI mode= value |
| For non-Rock Ridge volumes, give all files the indicated mode. |
| (Default: read permission for everybody.) |
| Since Linux 2.1.37 one no longer needs to specify the mode in |
| decimal. (Octal is indicated by a leading 0.) |
| .TP |
| .B unhide |
| Also show hidden and associated files. |
| (If the ordinary files and the associated or hidden files have |
| the same filenames, this may make the ordinary files inaccessible.) |
| .TP |
| .B block=[512|1024|2048] |
| Set the block size to the indicated value. |
| (Default: |
| .BR block=1024 .) |
| .TP |
| .BR conv=a[uto] " / " conv=b[inary] " / " conv=m[text] " / " conv=t[ext] |
| (Default: |
| .BR conv=binary .) |
| Since Linux 1.3.54 this option has no effect anymore. |
| (And non-binary settings used to be very dangerous, |
| possibly leading to silent data corruption.) |
| .TP |
| .B cruft |
| If the high byte of the file length contains other garbage, |
| set this mount option to ignore the high order bits of the file length. |
| This implies that a file cannot be larger than 16MB. |
| .TP |
| .BI session= x |
| Select number of session on multisession CD. (Since 2.3.4.) |
| .TP |
| .BI sbsector= xxx |
| Session begins from sector xxx. (Since 2.3.4.) |
| .LP |
| The following options are the same as for vfat and specifying them only makes |
| sense when using discs encoded using Microsoft's Joliet extensions. |
| .TP |
| .BI iocharset= value |
| Character set to use for converting 16 bit Unicode characters on CD |
| to 8 bit characters. The default is iso8859-1. |
| .TP |
| .B utf8 |
| Convert 16 bit Unicode characters on CD to UTF-8. |
| |
| .SH "Mount options for jfs" |
| .TP |
| .BI iocharset= name |
| Character set to use for converting from Unicode to ASCII. The default is |
| to do no conversion. Use |
| .B iocharset=utf8 |
| for UTF8 translations. This requires CONFIG_NLS_UTF8 to be set in |
| the kernel |
| .I ".config" |
| file. |
| .TP |
| .BI resize= value |
| Resize the volume to |
| .I value |
| blocks. JFS only supports growing a volume, not shrinking it. This option |
| is only valid during a remount, when the volume is mounted read-write. The |
| .B resize |
| keyword with no value will grow the volume to the full size of the partition. |
| .TP |
| .B nointegrity |
| Do not write to the journal. The primary use of this option is to allow |
| for higher performance when restoring a volume from backup media. The |
| integrity of the volume is not guaranteed if the system abnormally abends. |
| .TP |
| .B integrity |
| Default. Commit metadata changes to the journal. Use this option to remount |
| a volume where the |
| .B nointegrity |
| option was previously specified in order to restore normal behavior. |
| .TP |
| .BR errors=continue " / " errors=remount-ro " / " errors=panic |
| Define the behaviour when an error is encountered. |
| (Either ignore errors and just mark the file system erroneous and continue, |
| or remount the file system read-only, or panic and halt the system.) |
| .TP |
| .BR noquota " / " quota " / " usrquota " / " grpquota |
| These options are accepted but ignored. |
| |
| .SH "Mount options for minix" |
| None. |
| |
| .SH "Mount options for msdos" |
| See mount options for fat. |
| If the |
| .I msdos |
| file system detects an inconsistency, it reports an error and sets the file |
| system read-only. The file system can be made writeable again by remounting |
| it. |
| |
| .SH "Mount options for ncpfs" |
| Just like |
| .IR nfs ", the " ncpfs |
| implementation expects a binary argument (a |
| .IR "struct ncp_mount_data" ) |
| to the mount system call. This argument is constructed by |
| .BR ncpmount (8) |
| and the current version of |
| .B mount |
| (2.12) does not know anything about ncpfs. |
| |
| .SH "Mount options for nfs and nfs4" |
| See the options section of the |
| .BR nfs (5) |
| man page (nfs-utils package must be installed). |
| |
| The |
| .IR nfs " and " nfs4 |
| implementation expects a binary argument (a |
| .IR "struct nfs_mount_data" ) |
| to the mount system call. This argument is constructed by |
| .BR mount.nfs (8) |
| and the current version of |
| .B mount |
| (2.13) does not know anything about nfs and nfs4. |
| |
| .SH "Mount options for ntfs" |
| .TP |
| .BI iocharset= name |
| Character set to use when returning file names. |
| Unlike VFAT, NTFS suppresses names that contain |
| unconvertible characters. Deprecated. |
| .\" since 2.5.11 |
| .TP |
| .BI nls= name |
| New name for the option earlier called |
| .IR iocharset . |
| .\" since 2.5.11 |
| .TP |
| .BR utf8 |
| Use UTF-8 for converting file names. |
| .TP |
| .B uni_xlate=[0|1|2] |
| For 0 (or `no' or `false'), do not use escape sequences |
| for unknown Unicode characters. |
| For 1 (or `yes' or `true') or 2, use vfat-style 4-byte escape sequences |
| starting with ":". Here 2 give a little-endian encoding |
| and 1 a byteswapped bigendian encoding. |
| .TP |
| .B posix=[0|1] |
| If enabled (posix=1), the file system distinguishes between |
| upper and lower case. The 8.3 alias names are presented as |
| hard links instead of being suppressed. |
| .TP |
| \fBuid=\fP\fIvalue\fP, \fBgid=\fP\fIvalue\fP and \fBumask=\fP\fIvalue\fP |
| Set the file permission on the filesystem. |
| The umask value is given in octal. |
| By default, the files are owned by root and not readable by somebody else. |
| |
| .SH "Mount options for proc" |
| .TP |
| \fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP |
| These options are recognized, but have no effect as far as I can see. |
| |
| .SH "Mount options for ramfs" |
| Ramfs is a memory based filesystem. Mount it and you have it. Unmount it |
| and it is gone. Present since Linux 2.3.99pre4. |
| There are no mount options. |
| |
| .SH "Mount options for reiserfs" |
| Reiserfs is a journaling filesystem. |
| The reiserfs mount options are more fully described at |
| .IR http://www.namesys.com/mount-options.html . |
| .TP |
| .BR conv |
| Instructs version 3.6 reiserfs software to mount a version 3.5 file system, |
| using the 3.6 format for newly created objects. This file system will no |
| longer be compatible with reiserfs 3.5 tools. |
| .TP |
| .BR hash=rupasov " / " hash=tea " / " hash=r5 " / " hash=detect |
| Choose which hash function reiserfs will use to find files within directories. |
| .RS |
| .TP |
| .B rupasov |
| A hash invented by Yury Yu. Rupasov. It is fast and preserves locality, |
| mapping lexicographically close file names to close hash values. |
| This option should not be used, as it causes a high probability of hash |
| collisions. |
| .TP |
| .B tea |
| A Davis-Meyer function implemented by Jeremy Fitzhardinge. |
| It uses hash permuting bits in the name. It gets high randomness |
| and, therefore, low probability of hash collisions at some CPU cost. |
| This may be used if EHASHCOLLISION errors are experienced with the r5 hash. |
| .TP |
| .B r5 |
| A modified version of the rupasov hash. It is used by default and is |
| the best choice unless the file system has huge directories and |
| unusual file-name patterns. |
| .TP |
| .B detect |
| Instructs |
| .IR mount |
| to detect which hash function is in use by examining |
| the file system being mounted, and to write this information into |
| the reiserfs superblock. This is only useful on the first mount of |
| an old format file system. |
| .RE |
| .TP |
| .BR hashed_relocation |
| Tunes the block allocator. This may provide performance improvements |
| in some situations. |
| .TP |
| .BR no_unhashed_relocation |
| Tunes the block allocator. This may provide performance improvements |
| in some situations. |
| .TP |
| .BR noborder |
| Disable the border allocator algorithm invented by Yury Yu. Rupasov. |
| This may provide performance improvements in some situations. |
| .TP |
| .BR nolog |
| Disable journalling. This will provide slight performance improvements in |
| some situations at the cost of losing reiserfs's fast recovery from crashes. |
| Even with this option turned on, reiserfs still performs all journalling |
| operations, save for actual writes into its journalling area. Implementation |
| of |
| .IR nolog |
| is a work in progress. |
| .TP |
| .BR notail |
| By default, reiserfs stores small files and `file tails' directly into its |
| tree. This confuses some utilities such as |
| .BR LILO (8) . |
| This option is used to disable packing of files into the tree. |
| .TP |
| .BR replayonly |
| Replay the transactions which are in the journal, but do not actually |
| mount the file system. Mainly used by |
| .IR reiserfsck . |
| .TP |
| .BI resize= number |
| A remount option which permits online expansion of reiserfs partitions. |
| Instructs reiserfs to assume that the device has |
| .I number |
| blocks. |
| This option is designed for use with devices which are under logical |
| volume management (LVM). |
| There is a special |
| .I resizer |
| utility which can be obtained from |
| .IR ftp://ftp.namesys.com/pub/reiserfsprogs . |
| .TP |
| .BR user_xattr |
| Enable Extended User Attributes. See the |
| .BR attr (5) |
| manual page. |
| .TP |
| .BR acl |
| Enable POSIX Access Control Lists. See the |
| .BR acl (5) |
| manual page. |
| |
| .SH "Mount options for romfs" |
| None. |
| |
| .SH "Mount options for smbfs" |
| Just like |
| .IR nfs ", the " smbfs |
| implementation expects a binary argument (a |
| .IR "struct smb_mount_data" ) |
| to the mount system call. This argument is constructed by |
| .BR smbmount (8) |
| and the current version of |
| .B mount |
| (2.12) does not know anything about smbfs. |
| |
| .SH "Mount options for sysv" |
| None. |
| |
| .SH "Mount options for tmpfs" |
| The following parameters accept a suffix |
| .BR k , |
| .B m |
| or |
| .B g |
| for Ki, Mi, Gi (binary kilo, mega and giga) and can be changed on remount. |
| .TP |
| .BI size= nbytes |
| Override default maximum size of the filesystem. |
| The size is given in bytes, and rounded down to entire pages. |
| The default is half of the memory. |
| .TP |
| .B nr_blocks= |
| Set number of blocks. |
| .TP |
| .B nr_inodes= |
| Set number of inodes. |
| .TP |
| .B mode= |
| Set initial permissions of the root directory. |
| |
| .SH "Mount options for udf" |
| udf is the "Universal Disk Format" filesystem defined by the Optical |
| Storage Technology Association, and is often used for DVD-ROM. |
| See also |
| .IR iso9660 . |
| .TP |
| .B gid= |
| Set the default group. |
| .TP |
| .B umask= |
| Set the default umask. |
| The value is given in octal. |
| .TP |
| .B uid= |
| Set the default user. |
| .TP |
| .B unhide |
| Show otherwise hidden files. |
| .TP |
| .B undelete |
| Show deleted files in lists. |
| .TP |
| .B nostrict |
| Unset strict conformance. |
| .\" .TP |
| .\" .B utf8 |
| .\" (unused). |
| .TP |
| .B iocharset |
| Set the NLS character set. |
| .TP |
| .B bs= |
| Set the block size. (May not work unless 2048.) |
| .TP |
| .B novrs |
| Skip volume sequence recognition. |
| .TP |
| .B session= |
| Set the CDROM session counting from 0. Default: last session. |
| .TP |
| .B anchor= |
| Override standard anchor location. Default: 256. |
| .TP |
| .B volume= |
| Override the VolumeDesc location. (unused) |
| .TP |
| .B partition= |
| Override the PartitionDesc location. (unused) |
| .TP |
| .B lastblock= |
| Set the last block of the filesystem. |
| .TP |
| .B fileset= |
| Override the fileset block location. (unused) |
| .TP |
| .B rootdir= |
| Override the root directory location. (unused) |
| |
| .SH "Mount options for ufs" |
| .TP |
| .BI ufstype= value |
| UFS is a file system widely used in different operating systems. |
| The problem are differences among implementations. Features of some |
| implementations are undocumented, so its hard to recognize the |
| type of ufs automatically. |
| That's why the user must specify the type of ufs by mount option. |
| Possible values are: |
| .RS |
| .TP |
| .B old |
| Old format of ufs, this is the default, read only. |
| (Don't forget to give the \-r option.) |
| .TP |
| .B 44bsd |
| For filesystems created by a BSD-like system (NetBSD,FreeBSD,OpenBSD). |
| .TP |
| .B sun |
| For filesystems created by SunOS or Solaris on Sparc. |
| .TP |
| .B sunx86 |
| For filesystems created by Solaris on x86. |
| .TP |
| .B hp |
| For filesystems created by HP-UX, read-only. |
| .TP |
| .B nextstep |
| For filesystems created by NeXTStep (on NeXT station) (currently read only). |
| .TP |
| .B nextstep-cd |
| For NextStep CDROMs (block_size == 2048), read-only. |
| .TP |
| .B openstep |
| For filesystems created by OpenStep (currently read only). |
| The same filesystem type is also used by Mac OS X. |
| .RE |
| |
| .TP |
| .BI onerror= value |
| Set behaviour on error: |
| .RS |
| .TP |
| .B panic |
| If an error is encountered, cause a kernel panic. |
| .TP |
| .B [lock|umount|repair] |
| These mount options don't do anything at present; |
| when an error is encountered only a console message is printed. |
| .RE |
| |
| .SH "Mount options for umsdos" |
| See mount options for msdos. |
| The |
| .B dotsOK |
| option is explicitly killed by |
| .IR umsdos . |
| |
| .SH "Mount options for vfat" |
| First of all, the mount options for |
| .I fat |
| are recognized. |
| The |
| .B dotsOK |
| option is explicitly killed by |
| .IR vfat . |
| Furthermore, there are |
| .TP |
| .B uni_xlate |
| Translate unhandled Unicode characters to special escaped sequences. |
| This lets you backup and restore filenames that are created with any |
| Unicode characters. Without this option, a '?' is used when no |
| translation is possible. The escape character is ':' because it is |
| otherwise illegal on the vfat filesystem. The escape sequence |
| that gets used, where u is the unicode character, |
| is: ':', (u & 0x3f), ((u>>6) & 0x3f), (u>>12). |
| .TP |
| .B posix |
| Allow two files with names that only differ in case. |
| .TP |
| .B nonumtail |
| First try to make a short name without sequence number, |
| before trying |
| .IR name~num.ext . |
| .TP |
| .B utf8 |
| UTF8 is the filesystem safe 8-bit encoding of Unicode that is used |
| by the console. It can be be enabled for the filesystem with this option. |
| If `uni_xlate' gets set, UTF8 gets disabled. |
| .TP |
| .B shortname=[lower|win95|winnt|mixed] |
| |
| Defines the behaviour for creation and display of filenames which fit into |
| 8.3 characters. If a long name for a file exists, it will always be |
| preferred display. There are four modes: |
| .RS |
| .TP |
| .I lower |
| Force the short name to lower case upon display; store a long name when |
| the short name is not all upper case. |
| .TP |
| .I win95 |
| Force the short name to upper case upon display; store a long name when |
| the short name is not all upper case. |
| .TP |
| .I winnt |
| Display the shortname as is; store a long name when the short name is |
| not all lower case or all upper case. |
| .TP |
| .I mixed |
| Display the short name as is; store a long name when the short name is not |
| all upper case. |
| .RE |
| |
| The default is "lower". |
| |
| .SH "Mount options for usbfs" |
| .TP |
| \fBdevuid=\fP\fIuid\fP and \fBdevgid=\fP\fIgid\fP and \fBdevmode=\fP\fImode\fP |
| Set the owner and group and mode of the device files in the usbfs file system |
| (default: uid=gid=0, mode=0644). The mode is given in octal. |
| .TP |
| \fBbusuid=\fP\fIuid\fP and \fBbusgid=\fP\fIgid\fP and \fBbusmode=\fP\fImode\fP |
| Set the owner and group and mode of the bus directories in the usbfs |
| file system (default: uid=gid=0, mode=0555). The mode is given in octal. |
| .TP |
| \fBlistuid=\fP\fIuid\fP and \fBlistgid=\fP\fIgid\fP and \fBlistmode=\fP\fImode\fP |
| Set the owner and group and mode of the file |
| .I devices |
| (default: uid=gid=0, mode=0444). The mode is given in octal. |
| |
| .SH "Mount options for xenix" |
| None. |
| |
| .SH "Mount options for xfs" |
| .TP |
| .BI allocsize= size |
| Sets the buffered I/O end-of-file preallocation size when |
| doing delayed allocation writeout (default size is 64KiB). |
| Valid values for this option are page size (typically 4KiB) |
| through to 1GiB, inclusive, in power-of-2 increments. |
| .TP |
| .BR attr2 " / " noattr2 |
| The options enable/disable (default is disabled for backward |
| compatibility on-disk) an "opportunistic" improvement to be |
| made in the way inline extended attributes are stored on-disk. |
| When the new form is used for the first time (by setting or |
| removing extended attributes) the on-disk superblock feature |
| bit field will be updated to reflect this format being in use. |
| .TP |
| .B barrier |
| Enables the use of block layer write barriers for writes into |
| the journal and unwritten extent conversion. This allows for |
| drive level write caching to be enabled, for devices that |
| support write barriers. |
| .TP |
| .B dmapi |
| Enable the DMAPI (Data Management API) event callouts. |
| Use with the |
| .B mtpt |
| option. |
| .TP |
| \fBgrpid\fP / \fBbsdgroups\fP and \fBnogrpid\fP / \fBsysvgroups\fP |
| These options define what group ID a newly created file gets. |
| When grpid is set, it takes the group ID of the directory in |
| which it is created; otherwise (the default) it takes the fsgid |
| of the current process, unless the directory has the setgid bit |
| set, in which case it takes the gid from the parent directory, |
| and also gets the setgid bit set if it is a directory itself. |
| .TP |
| .BI ihashsize= value |
| Sets the number of hash buckets available for hashing the |
| in-memory inodes of the specified mount point. If a value |
| of zero is used, the value selected by the default algorithm |
| will be displayed in |
| .IR /proc/mounts . |
| .TP |
| .BR ikeep " / " noikeep |
| When inode clusters are emptied of inodes, keep them around |
| on the disk (ikeep) - this is the traditional XFS behaviour |
| and is still the default for now. Using the noikeep option, |
| inode clusters are returned to the free space pool. |
| .TP |
| .B inode64 |
| Indicates that XFS is allowed to create inodes at any location |
| in the filesystem, including those which will result in inode |
| numbers occupying more than 32 bits of significance. This is |
| provided for backwards compatibility, but causes problems for |
| backup applications that cannot handle large inode numbers. |
| .TP |
| .BR largeio " / " nolargeio |
| If |
| .B nolargeio |
| is specified, the optimal I/O reported in |
| st_blksize by |
| .BR stat (2) |
| will be as small as possible to allow user |
| applications to avoid inefficient read/modify/write I/O. |
| If |
| .B largeio |
| is specified, a filesystem that has a |
| .B swidth |
| specified |
| will return the |
| .B swidth |
| value (in bytes) in st_blksize. If the |
| filesystem does not have a |
| .B swidth |
| specified but does specify |
| an |
| .B allocsize |
| then |
| .B allocsize |
| (in bytes) will be returned |
| instead. |
| If neither of these two options are specified, then filesystem |
| will behave as if |
| .B nolargeio |
| was specified. |
| .TP |
| .BI logbufs= value |
| Set the number of in-memory log buffers. Valid numbers range |
| from 2-8 inclusive. |
| The default value is 8 buffers for filesystems with a |
| blocksize of 64KiB, 4 buffers for filesystems with a blocksize |
| of 32KiB, 3 buffers for filesystems with a blocksize of 16KiB |
| and 2 buffers for all other configurations. Increasing the |
| number of buffers may increase performance on some workloads |
| at the cost of the memory used for the additional log buffers |
| and their associated control structures. |
| .TP |
| .BI logbsize= value |
| Set the size of each in-memory log buffer. |
| Size may be specified in bytes, or in kilobytes with a "k" suffix. |
| Valid sizes for version 1 and version 2 logs are 16384 (16k) and |
| 32768 (32k). Valid sizes for version 2 logs also include |
| 65536 (64k), 131072 (128k) and 262144 (256k). |
| The default value for machines with more than 32MiB of memory |
| is 32768, machines with less memory use 16384 by default. |
| .TP |
| \fBlogdev=\fP\fIdevice\fP and \fBrtdev=\fP\fIdevice\fP |
| Use an external log (metadata journal) and/or real-time device. |
| An XFS filesystem has up to three parts: a data section, a log section, |
| and a real-time section. |
| The real-time section is optional, and the log section can be separate |
| from the data section or contained within it. |
| Refer to |
| .BR xfs (5). |
| .TP |
| .BI mtpt= mountpoint |
| Use with the |
| .B dmapi |
| option. The value specified here will be |
| included in the DMAPI mount event, and should be the path of |
| the actual mountpoint that is used. |
| .TP |
| .B noalign |
| Data allocations will not be aligned at stripe unit boundaries. |
| .TP |
| .B noatime |
| Access timestamps are not updated when a file is read. |
| .TP |
| .B norecovery |
| The filesystem will be mounted without running log recovery. |
| If the filesystem was not cleanly unmounted, it is likely to |
| be inconsistent when mounted in |
| .B norecovery |
| mode. |
| Some files or directories may not be accessible because of this. |
| Filesystems mounted |
| .B norecovery |
| must be mounted read-only or the mount will fail. |
| .TP |
| .B nouuid |
| Don't check for double mounted file systems using the file system uuid. |
| This is useful to mount LVM snapshot volumes. |
| .TP |
| .B osyncisdsync |
| Make O_SYNC writes implement true O_SYNC. WITHOUT this option, |
| Linux XFS behaves as if an |
| .B osyncisdsync |
| option is used, |
| which will make writes to files opened with the O_SYNC flag set |
| behave as if the O_DSYNC flag had been used instead. |
| This can result in better performance without compromising |
| data safety. |
| However if this option is not in effect, timestamp updates from |
| O_SYNC writes can be lost if the system crashes. |
| If timestamp updates are critical, use the |
| .B osyncisosync |
| option. |
| .TP |
| .BR uquota " / " usrquota " / " uqnoenforce " / " quota |
| User disk quota accounting enabled, and limits (optionally) |
| enforced. Refer to |
| .BR xfs_quota (8) |
| for further details. |
| .TP |
| .BR gquota " / " grpquota " / " gqnoenforce |
| Group disk quota accounting enabled and limits (optionally) |
| enforced. Refer to |
| .BR xfs_quota (8) |
| for further details. |
| .TP |
| .BR pquota " / " prjquota " / " pqnoenforce |
| Project disk quota accounting enabled and limits (optionally) |
| enforced. Refer to |
| .BR xfs_quota (8) |
| for further details. |
| .TP |
| \fBsunit=\fP\fIvalue\fP and \fBswidth=\fP\fIvalue\fP |
| Used to specify the stripe unit and width for a RAID device or a stripe |
| volume. |
| .I value |
| must be specified in 512-byte block units. |
| If this option is not specified and the filesystem was made on a stripe |
| volume or the stripe width or unit were specified for the RAID device at |
| mkfs time, then the mount system call will restore the value from the |
| superblock. |
| For filesystems that are made directly on RAID devices, these options can be |
| used to override the information in the superblock if the underlying disk |
| layout changes after the filesystem has been created. |
| The |
| .B swidth |
| option is required if the |
| .B sunit |
| option has been specified, |
| and must be a multiple of the |
| .B sunit |
| value. |
| .TP |
| .B swalloc |
| Data allocations will be rounded up to stripe width boundaries |
| when the current end of file is being extended and the file |
| size is larger than the stripe width size. |
| |
| .SH "Mount options for xiafs" |
| None. Although nothing is wrong with xiafs, it is not used much, |
| and is not maintained. Probably one shouldn't use it. |
| Since Linux version 2.1.21 xiafs is no longer part of the kernel source. |
| |
| .SH "THE LOOP DEVICE" |
| One further possible type is a mount via the loop device. For example, |
| the command |
| |
| .nf |
| .B " mount /tmp/fdimage /mnt -t msdos -o loop=/dev/loop3,blocksize=1024" |
| .fi |
| |
| will set up the loop device |
| .I /dev/loop3 |
| to correspond to the file |
| .IR /tmp/fdimage , |
| and then mount this device on |
| .IR /mnt . |
| |
| This type of mount knows about three options, namely |
| .BR loop ", " offset " and " encryption , |
| that are really options to |
| .BR \%losetup (8). |
| (These options can be used in addition to those specific |
| to the filesystem type.) |
| |
| If no explicit loop device is mentioned |
| (but just an option `\fB\-o loop\fP' is given), then |
| .B mount |
| will try to find some unused loop device and use that. |
| If you are not so unwise as to make |
| .I /etc/mtab |
| a symbolic link to |
| .I /proc/mounts |
| then any loop device allocated by |
| .B mount |
| will be freed by |
| .BR umount . |
| You can also free a loop device by hand, using `losetup -d', see |
| .BR losetup (8). |
| |
| .SH RETURN CODES |
| .B mount |
| has the following return codes (the bits can be ORed): |
| .TP |
| .BR 0 |
| success |
| .TP |
| .BR 1 |
| incorrect invocation or permissions |
| .TP |
| .BR 2 |
| system error (out of memory, cannot fork, no more loop devices) |
| .TP |
| .BR 4 |
| internal |
| .B mount |
| bug |
| .TP |
| .BR 8 |
| user interrupt |
| .TP |
| .BR 16 |
| problems writing or locking /etc/mtab |
| .TP |
| .BR 32 |
| mount failure |
| .TP |
| .BR 64 |
| some mount succeeded |
| |
| .SH NOTES |
| The syntax of external mount helpers is: |
| |
| .br |
| .BI "/sbin/mount.<suffix> spec dir [\-sfnv] [\-o options] |
| .br |
| |
| where the <suffix> is filesystem type and \-sfnvo options have same meaning like |
| standard mount options. |
| |
| .SH FILES |
| .TP 18n |
| .I /etc/fstab |
| file system table |
| .TP |
| .I /etc/mtab |
| table of mounted file systems |
| .TP |
| .I /etc/mtab~ |
| lock file |
| .TP |
| .I /etc/mtab.tmp |
| temporary file |
| .TP |
| .I /etc/filesystems |
| a list of filesystem types to try |
| |
| .SH "SEE ALSO" |
| .BR mount (2), |
| .BR umount (2), |
| .BR fstab (5), |
| .BR umount (8), |
| .BR swapon (8), |
| .BR nfs (5), |
| .BR xfs (5), |
| .BR e2label (8), |
| .BR xfs_admin (8), |
| .BR mountd (8), |
| .BR nfsd (8), |
| .BR mke2fs (8), |
| .BR tune2fs (8), |
| .BR losetup (8) |
| .SH BUGS |
| It is possible for a corrupted file system to cause a crash. |
| .PP |
| Some Linux file systems don't support |
| .B "\-o sync and \-o dirsync" |
| (the ext2, ext3, fat and vfat file systems |
| .I do |
| support synchronous updates (a la BSD) when mounted with the |
| .B sync |
| option). |
| .PP |
| The |
| .B "\-o remount" |
| may not be able to change mount parameters (all |
| .IR ext2fs -specific |
| parameters, except |
| .BR sb , |
| are changeable with a remount, for example, but you can't change |
| .B gid |
| or |
| .B umask |
| for the |
| .IR fatfs ). |
| .PP |
| Mount by label or uuid will work only if your devices have the names listed in |
| .IR /proc/partitions . |
| In particular, it may well fail if the kernel was compiled with devfs |
| but devfs is not mounted. |
| .PP |
| It is possible that files |
| .IR /etc/mtab |
| and |
| .IR /proc/mounts |
| don't match. The first file is based only on the mount command options, but the |
| content of the second file also depends on the kernel and others settings (e.g. |
| remote NFS server. In particular case the mount command may reports unreliable |
| information about a NFS mount point and the /proc/mounts file usually contains |
| more reliable information.) |
| .PP |
| Checking files on NFS filesystem referenced by file descriptors (i.e. the |
| .BR fcntl |
| and |
| .BR ioctl |
| families of functions) may lead to inconsistent result due to the lack of |
| consistency check in kernel even if noac is used. |
| .SH HISTORY |
| A |
| .B mount |
| command existed in Version 5 AT&T UNIX. |
| .SH AVAILABILITY |
| The mount command is part of the util-linux-ng package and is available from |
| ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/. |
| |