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diff --git a/mount-deprecated/mount.8 b/mount-deprecated/mount.8 deleted file mode 100644 index 8708fcafd..000000000 --- a/mount-deprecated/mount.8 +++ /dev/null @@ -1,2849 +0,0 @@ -.\" 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 program; if not, write to the Free Software Foundation, Inc., -.\" 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 "December 2004" "util-linux" "System Administration" -.SH NAME -mount \- mount a filesystem -.SH SYNOPSIS -.B mount -.RB [ \-lhV ] -.LP -.BI "mount \-a -.RB [ \-fFnrsvw ] -.RB [ \-t -.IR vfstype ] -.RB [ \-O -.IR optlist ] -.LP -.B mount -.RB [ \-fnrsvw ] -.RB [ \-o -.IR option [ \fB,\fPoption ]...] -.IR device | dir -.LP -.B mount -.RB [ \-fnrsvw ] -.RB [ \-t -.IB vfstype ] -.RB [ \-o -.IR options ] -.I 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 filesystem 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" -.br - -.RE -This tells the kernel to attach the filesystem 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 filesystem remains mounted, -the pathname -.I dir -refers to the root of the filesystem on -.IR device . - -If only directory or device is given, for example: -.RS - -.br -.BI "mount /dir" -.br - -.RE -then mount looks for a mountpoint and if not found then for a device in the -/etc/fstab file. - -.B The listing and help. -.RS -Three forms of invocation do not actually mount anything: -.TP -.B "mount \-h" -prints a help message -.TP -.B "mount \-V" -prints a version string -.TP -.BR "mount " [ -l "] [" "-t \fItype\fP" ] -lists all mounted filesystems (of type -.IR type ). -The option \-l adds the labels in this listing. -See below. -.RE - -.B The device indication. -.RS -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 -.B LABEL -or -.B UUID -(see the \-L and \-U options below). - -The recommended setup is to use LABEL=<label> or UUID=<uuid> tags rather than -.B /dev/disk/by-{label,uuid} -udev symlinks in the /etc/fstab file. The tags are -more readable, robust and portable. The -.BR mount (8) -command internally uses udev -symlinks, so use the symlinks in /etc/fstab has no advantage over LABEL=/UUID=. -For more details see -.BR libblkid (3). - -Note that -.BR mount (8) -uses UUIDs as strings. The UUIDs from command line or -.BR fstab (5) -are not converted to internal binary representation. The string representation -of the UUID should be based on lower case characters. - -The -.I proc -filesystem 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.) -.RE - -.B The /etc/fstab, /etc/mtab and /proc/mounts files. -.RS -The file -.I /etc/fstab -(see -.BR fstab (5)), -may contain lines describing what devices are usually -mounted where, using which options. -.LP -The command -.RS -.sp -.B mount \-a -.RB [ \-t -.IR type ] -.RB [ \-O -.IR optlist ] -.sp -.RE -(usually given in a bootscript) causes all filesystems 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 -When mounting a filesystem mentioned in -.IR fstab -or -.IR mtab , -it suffices to give only the device, or only the mount point. - - -The programs -.B mount -and -.B umount -maintain a list of currently mounted filesystems in the file -.IR /etc/mtab . -If no arguments are given to -.BR mount , -this list is printed. - -The -.B mount -program does not read the -.I /etc/fstab -file if -.I device -(or LABEL/UUID) and -.I dir -are specified. For example: -.RS -.sp -.B "mount /dev/foo /dir" -.sp -.RE -If you want to override mount options from -.I /etc/fstab -you have to use: -.RS -.sp -.B "mount device|dir -o <options>" -.sp -.RE -and then the mount options from command line will be appended to -the list of options from -.IR /etc/fstab . -The usual behaviour is that the last option wins if there is more duplicated -options. - -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 -using the "user" option will fail. -.RE - -.B The non-superuser mounts. -.RS -Normally, only the superuser can mount filesystems. -However, when -.I fstab -contains the -.B user -option on a line, anybody can mount the corresponding system. -.LP -Thus, given a line -.RS -.sp -.B "/dev/cdrom /cd iso9660 ro,user,noauto,unhide" -.sp -.RE -any user can mount the iso9660 filesystem found on his CDROM -using the command -.RS -.sp -.B "mount /dev/cdrom" -.sp -.RE -or -.RS -.sp -.B "mount /cd" -.sp -.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. -.RE - - -.B The bind mounts. -.RS -.\" 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 -.I olddir newdir -.RE -or shortoption -.RS -.br -.B mount -B -.I olddir newdir -.RE -or fstab entry is: -.RS -.br -.I /olddir -.I /newdir -.B none bind -.RE - -After this call the same contents is accessible in two places. -One can also remount a single file (on a single file). It's also -possible to use the bind mount to create a mountpoint from a regular -directory, for example: - -.RS -.br -.B mount --bind -.I foo foo -.RE - -The bind mount 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 -.I olddir newdir -.RE - -or shortoption - -.RS -.br -.B mount -R -.I 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. The mount options can be -changed by a separate remount command, for example: - -.RS -.br -.B mount --bind -.I olddir newdir -.br -.B mount -o remount,ro -.I newdir -.RE - -Note that behavior of the remount operation depends on the /etc/mtab file. The -first command stores the 'bind' flag to the /etc/mtab file and the second -command reads the flag from the file. If you have a system without the -/etc/mtab file or if you explicitly define source and target for the remount -command (then mount(8) does not read /etc/mtab), then you have to use bind flag -(or option) for the remount command too. For example: - -.RS -.br -.B mount --bind -.I olddir newdir -.br -.B mount -o remount,ro,bind -.I olddir newdir -.RE -.RE - -.B The move operation. -.RS -Since Linux 2.5.1 it is possible to atomically move a -.B mounted tree -to another place. The call is -.RS -.br -.B mount --move -.I olddir newdir -.RE -or shortoption -.RS -.br -.B mount -M -.I olddir newdir -.RE -This will cause the contents which previously appeared under olddir to be -accessed under newdir. The physical location of the files is not changed. -Note that the -.I olddir -has to be a mountpoint. -.RE - -.B The shared subtrees operations. -.RS -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 be cloned through a bind -operation. Detailed semantics is documented in Documentation/filesystems/sharedsubtree.txt -file in the kernel source tree. - -.RS -.nf -.BI "mount --make-shared " mountpoint -.BI "mount --make-slave " mountpoint -.BI "mount --make-private " mountpoint -.BI "mount --make-unbindable " mountpoint -.fi -.RE - -The following commands allows one to recursively change the type of all the -mounts under a given mountpoint. - -.RS -.nf -.BI "mount --make-rshared " mountpoint -.BI "mount --make-rslave " mountpoint -.BI "mount --make-rprivate " mountpoint -.BI "mount --make-runbindable " mountpoint -.fi -.RE -.RE - -.SH COMMAND LINE OPTIONS -The full set of mount options used by an invocation of -.B mount -is determined by first extracting the -mount options for the filesystem 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. - -Command line options available for the -.B mount -command: -.IP "\fB\-V, \-\-version\fP" -Display version information and exit. -.IP "\fB\-h, \-\-help\fP" -Display help text and exit. -.IP "\fB\-v, \-\-verbose\fP" -Verbose mode. -.IP "\fB\-a, \-\-all\fP" -Mount all filesystems (of the given types) mentioned in -.IR fstab . -.IP "\fB\-F, \-\-fork\fP" -(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 . -.IP "\fB\-f, \-\-fake\fP" -Causes everything to be done except for the actual system call; if it's not -obvious, this ``fakes'' mounting the filesystem. 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). -.IP "\fB\-i, \-\-internal\-only\fP" -Don't call the /sbin/mount.<filesystem> helper even if it exists. -.IP "\fB\-l\fP" -Add the 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, ext3 or ext4 using the -.BR e2label (8) -utility, or for XFS using -.BR xfs_admin (8), -or for reiserfs using -.BR reiserfstune (8). -.IP "\fB\-n, \-\-no\-mtab\fP" -Mount without writing in -.IR /etc/mtab . -This is necessary for example when -.I /etc -is on a read-only filesystem. -.IP "\fB\-\-no\-canonicalize\fP" -Don't canonicalize paths. The mount command canonicalizes all paths -(from command line or fstab) and stores canonicalized paths to the -.IR /etc/mtab -file. This option can be used together with the -.B \-f -flag for already canonicalized absolute paths. -.IP "\fB\-s\fP" -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. -.IP "\fB\-r, \-\-read\-only\fP" -Mount the filesystem read-only. A synonym is -.BR "\-o ro" . - -Note that, depending on the filesystem type, state and kernel behavior, the -system may still write to the device. For example, Ext3 or ext4 will replay its -journal if the filesystem is dirty. To prevent this kind of write access, you -may want to mount ext3 or ext4 filesystem with "ro,noload" mount options or -set the block device to read-only mode, see command -.BR blockdev (8). -.IP "\fB\-w, \-\-rw\fP" -Mount the filesystem read/write. This is the default. A synonym is -.BR "\-o rw" . -.IP "\fB\-L \fIlabel\fP" -Mount the partition that has the specified -.IR label . -.IP "\fB\-U \fIuuid\fP" -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. -.IP "\fB\-t, \-\-types \fIvfstype\fP" -The argument following the -.B \-t -is used to indicate the filesystem type. The filesystem 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 ext4 , -.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 squashfs , -.IR smbfs , -.IR sysv , -.IR tmpfs , -.IR ubifs , -.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. - -The programs -.B mount -and -.B umount -support filesystem subtypes. The subtype is defined by '.subtype' suffix. For -example 'fuse.sshfs'. It's recommended to use subtype notation rather than add -any prefix to the mount source (for example 'sshfs#example.com' is -depreacated). - -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 filesystems -have a separate mount program. In order to make it possible to -treat all types in a uniform way, mount will execute the program -.BI /sbin/mount. TYPE -(if that exists) when called with type -.IR TYPE . -Since various versions of the -.B smbmount -program have different calling conventions, -.B /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 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. - -More than one type may be specified in a comma separated -list. The list of filesystem types can be prefixed with -.B no -to specify the filesystem types on which no action should be taken. -(This can be meaningful with the -.B \-a -option.) For example, the command: -.RS -.RS -.sp -.B "mount \-a \-t nomsdos,ext" -.sp -.RE -mounts all filesystems except those of type -.I msdos -and -.IR ext . -.RE -.IP "\fB\-O, \-\-test-opts \fIopts\fP" -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 -.sp -.B "mount \-a \-O no_netdev" -.sp -.RE -mounts all filesystems 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 -.sp -.B "mount \-a \-t ext2 \-O _netdev" -.sp -.RE -mounts all ext2 filesystems with the _netdev option, not all filesystems -that are either ext2 or have the _netdev option specified. -.RE -.IP "\fB\-o, \-\-options \fIopts\fP" -Options are specified with a -.B \-o -flag followed by a comma separated string of options. For example: -.RS -.RS -.sp -.B "mount LABEL=mydisk \-o noatime,nouser" -.sp -.RE - -For more details, see -.B FILESYSTEM INDEPENDENT MOUNT OPTIONS -and -.B FILESYSTEM SPECIFIC MOUNT OPTIONS -sections. -.RE -.IP "\fB\-B, \-\-bind\fP" -Remount a subtree somewhere else (so that its contents are available -in both places). See above. -.IP "\fB\-R, \-\-rbind\fP" -Remount a subtree and all possible submounts somewhere else (so that its -contents are available in both places). See above. -.IP "\fB\-M, \-\-move\fP" -Move a subtree to some other place. See above. - -.SH FILESYSTEM INDEPENDENT MOUNT OPTIONS -Some of these options are only useful when they appear in the -.I /etc/fstab -file. - -Some of these options could be enabled or disabled by default -in the system kernel. To check the current setting see the options -in /proc/mounts. - -The following options apply to any filesystem that is being -mounted (but not every filesystem actually honors them - e.g., the -.B sync -option today has effect only for ext2, ext3, fat, vfat and ufs): - -.TP -.B async -All I/O to the filesystem should be done asynchronously. (See also the -.B sync -option.) -.TP -.B atime -Do not use noatime feature, then the inode access time is controlled by kernel -defaults. See also the description for -.B strictatime -and -.B relatime -mount options. -.TP -.B noatime -Do not update inode access times on this filesystem (e.g., for faster -access on the news spool to speed up news servers). -.TP -.B auto -Can be mounted with the -.B \-a -option. -.TP -.B noauto -Can only be mounted explicitly (i.e., the -.B \-a -option will not cause the filesystem to be mounted). -.TP -\fBcontext=\fP\fIcontext\fP, \fBfscontext=\fP\fIcontext\fP, \fBdefcontext=\fP\fIcontext\fP and \fBrootcontext=\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 -filesystem that supports xattr labeling. - -The -.BR rootcontext= -option allows you to explicitly label the root inode of a FS being mounted -before that FS or inode because visible to userspace. This was found to be -useful for things like stateless linux. - -Note that kernel rejects any remount request that includes the context -option even if unchanged from the current context. - -.B Warning that \fIcontext\fP value might contains comma -and in this case the value has to be properly quoted otherwise -.BR mount (8) -will interpret the comma as separator between mount options. Don't forget that -shell strips off quotes and -.BR "double quoting is required" , -for example: -.RS -.RS -.sp -mount -t tmpfs none /mnt \-o 'context="system_u:object_r:tmp_t:s0:c127,c456",noexec' -.sp -.RE - -For more details, see -.BR selinux (8) -.RE - -.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 filesystem. -.TP -.B nodev -Do not interpret character or block special devices on the file -system. -.TP -.B diratime -Update directory inode access times on this filesystem. This is the default. -.TP -.B nodiratime -Do not update directory inode access times on this filesystem. -.TP -.B dirsync -All directory updates within the filesystem should be done synchronously. -This affects the following system calls: creat, link, unlink, symlink, -mkdir, rmdir, mknod and rename. -.TP -.B exec -Permit execution of binaries. -.TP -.B noexec -Do not allow direct execution of any binaries on the mounted filesystem. -(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 group -Allow an ordinary (i.e., non-root) user to mount the filesystem 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 iversion -Every time the inode is modified, the i_version field will be incremented. -.TP -.B noiversion -Do not increment the i_version inode field. -.TP -.B mand -Allow mandatory locks on this filesystem. See -.BR fcntl (2). -.TP -.B nomand -Do not allow mandatory locks on this filesystem. -.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 nofail -Do not report errors for this device if it does not exist. -.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.) - -Since Linux 2.6.30, the kernel defaults to the behavior provided by this -option (unless -.B noatime -was specified), and the -.B strictatime -option is required to obtain traditional semantics. In addition, since Linux -2.6.30, the file's last access time is always updated if it is more than 1 -day old. -.TP -.B norelatime -Do not use -.B relatime -feature. See also the -.B strictatime -mount option. -.TP -.B strictatime -Allows to explicitly requesting full atime updates. This makes it -possible for kernel to defaults to -.B relatime -or -.B noatime -but still allow userspace to override it. For more details about the default -system mount options see /proc/mounts. -.TP -.B nostrictatime -Use the kernel's default behaviour for inode access time updates. -.TP -.B suid -Allow set-user-identifier or set-group-identifier bits to take -effect. -.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 silent -Turn on the silent flag. -.TP -.B loud -Turn off the silent flag. -.TP -.B owner -Allow an ordinary (i.e., non-root) user to mount the filesystem 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 filesystem. This is commonly -used to change the mount flags for a filesystem, especially to make a -readonly filesystem writable. It does not change device or mount point. - -The remount functionality follows the standard way how the mount command works -with options from fstab. It means the mount command doesn't read fstab (or -mtab) only when a -.IR device -and -.IR dir -are fully specified. - -.BR "mount -o remount,rw /dev/foo /dir" - -After this call all old mount options are replaced and arbitrary stuff from -fstab is ignored, except the loop= option which is internally generated and -maintained by the mount command. - -.BR "mount -o remount,rw /dir" - -After this call mount reads fstab (or mtab) and merges these options with -options from command line ( -.B -o -). -.TP -.B ro -Mount the filesystem read-only. -.TP -.B rw -Mount the filesystem read-write. -.TP -.B sync -All I/O to the filesystem 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 user -Allow an ordinary user to mount the filesystem. -The name of the mounting user is written to mtab so that he can unmount -the filesystem 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 nouser -Forbid an ordinary (i.e., non-root) user to mount the filesystem. -This is the default. -.TP -.B users -Allow every user to mount and unmount the filesystem. -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 ). - -.SH "FILESYSTEM SPECIFIC MOUNT OPTIONS" -The following options apply only to certain filesystems. -We sort them by filesystem. 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 filesystem (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 filesystem (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 filesystem. -.TP -.B usemp -Set uid and gid of the root of the filesystem 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-utils package must be installed). - -.SH "Mount options for coherent" -None. - -.SH "Mount options for debugfs" -The debugfs filesystem is a pseudo filesystem, 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 filesystem is a pseudo filesystem, 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. -.TP -\fBnewinstance -Create a private instance of devpts filesystem, such that -indices of ptys allocated in this new instance are -independent of indices created in other instances of devpts. - -All mounts of devpts without this -.B newinstance -option share the same set of pty indices (i.e legacy mode). -Each mount of devpts with the -.B newinstance -option has a private set of pty indices. - -This option is mainly used to support containers in the -linux kernel. It is implemented in linux kernel versions -starting with 2.6.29. Further, this mount option is valid -only if CONFIG_DEVPTS_MULTIPLE_INSTANCES is enabled in the -kernel configuration. - -To use this option effectively, -.IR /dev/ptmx -must be a symbolic link to -.IR pts/ptmx. -See -.IR Documentation/filesystems/devpts.txt -in the linux kernel source tree for details. -.TP -.BI ptmxmode= value - -Set the mode for the new -.IR ptmx -device node in the devpts filesystem. - -With the support for multiple instances of devpts (see -.B newinstance -option above), each instance has a private -.IR ptmx -node in the root of the devpts filesystem (typically -.IR /dev/pts/ptmx). - -For compatibility with older versions of the kernel, the -default mode of the new -.IR ptmx -node is 0000. -.BI ptmxmode= value -specifies a more useful mode for the -.IR ptmx -node and is highly recommended when the -.B newinstance -option is specified. - -This option is only implemented in linux kernel versions -starting with 2.6.29. Further this option is valid only if -CONFIG_DEVPTS_MULTIPLE_INSTANCES is enabled in the kernel -configuration. - -.SH "Mount options for ext" -None. -Note that the `ext' filesystem 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' filesystem is the standard Linux filesystem. -.\" 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 filesystem, while the -.B bsddf -behaviour (which is the default) is to subtract the overhead blocks -used by the ext2 filesystem and not available for file storage. Thus -.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 " or " 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. The non-default behavior is unsupported -(check=normal and check=strict options have been removed). Note that these mount options -don't have to be supported if ext4 kernel driver is used for ext2 and ext3 filesystems. -.TP -.B debug -Print debugging info upon each (re)mount. -.TP -.BR errors= { continue | remount-ro | panic } -Define the behaviour when an error is encountered. -(Either ignore errors and just mark the filesystem erroneous and continue, -or remount the filesystem 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 | bsdgroups " and " nogrpid | 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 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 filesystem 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 filesystem is a version of the ext2 filesystem which has been -enhanced with journaling. It supports the same options as ext2 as -well as the following additions: -.\" .TP -.\" .BR abort -.\" Mount the filesystem in abort mode, as if a fatal error has occurred. -.TP -.BR journal=update -Update the ext3 filesystem'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 filesystem's -journal file; ext3 will create a new journal, overwriting the old contents -of the file whose inode number is -.IR inum . -.TP -.BR journal_dev=devnum -When the external journal device's major/minor numbers -have changed, this option allows the user to specify -the new journal location. The journal device is -identified through its new major/minor numbers encoded -in devnum. -.TP -.BR norecovery / noload -Don't load the journal on mounting. Note that -if the filesystem was not unmounted cleanly, -skipping the journal replay will lead to the -filesystem containing inconsistencies that can -lead to any number of problems. -.TP -.BR data= { journal | ordered | writeback } -Specifies the journaling mode for file data. Metadata is always journaled. -To use modes other than -.B ordered -on the root filesystem, 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 filesystem. -.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 -filesystem after its metadata has been committed to the journal. -This is rumoured to be the highest-throughput option. It guarantees -internal filesystem integrity, however it can allow old data to appear -in files after a crash and journal recovery. -.RE -.TP -.BR barrier=0 " / " barrier=1 " -This enables/disables barriers. barrier=0 disables it, barrier=1 enables it. -Write barriers enforce proper on-disk ordering of journal commits, making -volatile disk write caches safe to use, at some performance penalty. The ext3 -filesystem does not enable write barriers by default. Be sure to enable -barriers unless your disks are battery-backed one way or another. Otherwise -you risk filesystem corruption in case of power failure. -.TP -.BI commit= nrsec -Sync all data and metadata every -.I nrsec -seconds. The default value is 5 seconds. Zero means default. -.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 ext4" -The ext4 filesystem is an advanced level of the ext3 filesystem which -incorporates scalability and reliability enhancements for supporting large -filesystem. - -The options -.B journal_dev, noload, data, commit, orlov, oldalloc, [no]user_xattr -.B [no]acl, bsddf, minixdf, debug, errors, data_err, grpid, bsdgroups, nogrpid -.B sysvgroups, resgid, resuid, sb, quota, noquota, grpquota and usrquota -are backwardly compatible with ext3 or ext2. -.TP -.BR journal_checksum -Enable checksumming of the journal transactions. This will allow the recovery -code in e2fsck and the kernel to detect corruption in the kernel. It is a -compatible change and will be ignored by older kernels. -.TP -.BR journal_async_commit -Commit block can be written to disk without waiting for descriptor blocks. If -enabled older kernels cannot mount the device. -This will enable 'journal_checksum' internally. -.TP -.BR barrier=0 " / " barrier=1 " / " barrier " / " nobarrier -This enables/disables the use of write barriers in the jbd code. barrier=0 -disables, barrier=1 enables. This also requires an IO stack which can support -barriers, and if jbd gets an error on a barrier write, it will disable again -with a warning. Write barriers enforce proper on-disk ordering of journal -commits, making volatile disk write caches safe to use, at some performance -penalty. If your disks are battery-backed in one way or another, disabling -barriers may safely improve performance. The mount options "barrier" and -"nobarrier" can also be used to enable or disable barriers, for consistency -with other ext4 mount options. - -The ext4 filesystem enables write barriers by default. -.TP -.BI inode_readahead= n -This tuning parameter controls the maximum number of inode table blocks that -ext4's inode table readahead algorithm will pre-read into the buffer cache. -The default value is 32 blocks. -.TP -.BI stripe= n -Number of filesystem blocks that mballoc will try to use for allocation size -and alignment. For RAID5/6 systems this should be the number of data disks * -RAID chunk size in filesystem blocks. -.TP -.BR delalloc -Deferring block allocation until write-out time. -.TP -.BR nodelalloc -Disable delayed allocation. Blocks are allocated when data is copied from user -to page cache. -.TP -.BI max_batch_time= usec -Maximum amount of time ext4 should wait for additional filesystem operations to -be batch together with a synchronous write operation. Since a synchronous -write operation is going to force a commit and then a wait for the I/O -complete, it doesn't cost much, and can be a huge throughput win, we wait for a -small amount of time to see if any other transactions can piggyback on the -synchronous write. The algorithm used is designed to automatically tune for -the speed of the disk, by measuring the amount of time (on average) that it -takes to finish committing a transaction. Call this time the "commit time". -If the time that the transaction has been running is less than the commit time, -ext4 will try sleeping for the commit time to see if other operations will join -the transaction. The commit time is capped by the max_batch_time, which -defaults to 15000us (15ms). This optimization can be turned off entirely by -setting max_batch_time to 0. -.TP -.BI min_batch_time= usec -This parameter sets the commit time (as described above) to be at least -min_batch_time. It defaults to zero microseconds. Increasing this parameter -may improve the throughput of multi-threaded, synchronous workloads on very -fast disks, at the cost of increasing latency. -.TP -.BI journal_ioprio= prio -The I/O priority (from 0 to 7, where 0 is the highest priority) which should be -used for I/O operations submitted by kjournald2 during a commit operation. -This defaults to 3, which is a slightly higher priority than the default I/O -priority. -.TP -.BR abort -Simulate the effects of calling ext4_abort() for -debugging purposes. This is normally used while -remounting a filesystem which is already mounted. -.TP -.BR auto_da_alloc | noauto_da_alloc -Many broken applications don't use fsync() when -replacing existing files via patterns such as - -fd = open("foo.new")/write(fd,..)/close(fd)/ rename("foo.new", "foo") - -or worse yet - -fd = open("foo", O_TRUNC)/write(fd,..)/close(fd). - -If auto_da_alloc is enabled, ext4 will detect the replace-via-rename and -replace-via-truncate patterns and force that any delayed allocation blocks are -allocated such that at the next journal commit, in the default data=ordered -mode, the data blocks of the new file are forced to disk before the rename() -operation is committed. This provides roughly the same level of guarantees as -ext3, and avoids the "zero-length" problem that can happen when a system -crashes before the delayed allocation blocks are forced to disk. -.TP -.BR discard / nodiscard -Controls whether ext4 should issue discard/TRIM commands to the underlying -block device when blocks are freed. This is useful for SSD devices and -sparse/thinly-provisioned LUNs, but it is off by default until sufficient -testing has been done. -.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 resize -Allows to resize filesystem to the end of the last -existing block group, further resize has to be done -with resize2fs either online, or offline. It can be -used only with conjunction with remount. -.TP -.BR block_validity / noblock_validity -This options allows to enables/disables the in-kernel facility for tracking -filesystem metadata blocks within internal data structures. This allows multi- -block allocator and other routines to quickly locate extents which might -overlap with filesystem metadata blocks. This option is intended for debugging -purposes and since it negatively affects the performance, it is off by default. -.TP -.BR dioread_lock / dioread_nolock -Controls whether or not ext4 should use the DIO read locking. If the -dioread_nolock option is specified ext4 will allocate uninitialized extent -before buffer write and convert the extent to initialized after IO completes. -This approach allows ext4 code to avoid using inode mutex, which improves -scalability on high speed storages. However this does not work with data -journaling and dioread_nolock option will be ignored with kernel warning. -Note that dioread_nolock code path is only used for extent-based files. -Because of the restrictions this options comprises it is off by default -(e.g. dioread_lock). -.TP -.BR i_version -Enable 64-bit inode version support. This option is off by default. - -.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 | 1024 | 2048 } -Set blocksize (default 512). This option is obsolete. -.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 allow_utime= value -This option controls the permission check of mtime/atime. -.RS -.TP -.B 20 -If current process is in group of file's group ID, you can change timestamp. -.TP -.B 2 -Other users can change timestamp. -.PP -The default is set from `dmask' option. (If the directory is writable, -.BR utime (2) -is also allowed. I.e. ~dmask & 022) - -Normally -.BR utime (2) -checks current process is owner of the file, or it has -CAP_FOWNER capability. But FAT filesystem doesn't have uid/gid on disk, so -normal check is too inflexible. With this option you can relax it. -.RE -.TP -.BI check= value -Three different levels of pickyness can be chosen: -.RS -.TP -.BR 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 -.BR n [ ormal ] -Like "relaxed", but many special characters (*, ?, <, spaces, etc.) are -rejected. This is the default. -.TP -.BR 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 ]| t [ ext ]| a [ uto ]} -The -.I fat -filesystem 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 filesystems mounted in binary mode, a conversion tool -(fromdos/todos) is available. This option is obsolete. -.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. -This option is obsolete. -.TP -.BI cvf_option= option -Option passed to the CVF module. This option is obsolete. -.TP -.B debug -Turn on the -.I debug -flag. A version string and a list of filesystem parameters will be -printed (these data are also printed if the parameters appear to be -inconsistent). -.TP -.BR fat= {12 | 16 | 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 -.BI tz=UTC -This option disables the conversion of timestamps -between local time (as used by Windows on FAT) and UTC -(which Linux uses internally). This is particularly -useful when mounting devices (like digital cameras) -that are set to UTC in order to avoid the pitfalls of -local time. -.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 showexec -If set, the execute permission bits of the file will be allowed only if -the extension part of the name is .EXE, .COM, or .BAT. Not set by default. -.TP -.B sys_immutable -If set, ATTR_SYS attribute on FAT is handled as IMMUTABLE flag on Linux. -Not set by default. -.TP -.B flush -If set, the filesystem will try to flush to disk more early than normal. -Not set by default. -.TP -.B usefree -Use the "free clusters" value stored on FSINFO. It'll -be used to determine number of free clusters without -scanning disk. But it's not used by default, because -recent Windows don't update it correctly in some -case. If you are sure the "free clusters" on FSINFO is -correct, by this option you can avoid scanning disk. -.TP -.BR dots ", " nodots ", " dotsOK= [ yes | no ] -Various misguided attempts to force Unix or DOS conventions -onto a FAT filesystem. - -.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 | asis } -Convert all files names to lower case, or leave them. -(Default: -.BR case=lower .) -.TP -.BR conv= { binary | text | 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 filesystem (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 ]| 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 filesystem 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 ]| o [ ff ]| 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 -.BR block= { 512 | 1024 | 2048 } -Set the block size to the indicated value. -(Default: -.BR block=1024 .) -.TP -.BR conv= { a [ uto ]| b [ inary ]| m [ text ]| 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 ends. -.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 | remount-ro | panic } -Define the behaviour when an error is encountered. -(Either ignore errors and just mark the filesystem erroneous and continue, -or remount the filesystem 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 -filesystem detects an inconsistency, it reports an error and sets the file -system read-only. The filesystem can be made writable 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 -nonconvertible 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 -.BR 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 filesystem distinguishes between -upper and lower case. The 8.3 alias names are presented as -hard links instead of being suppressed. This option is obsolete. -.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. -.TP -.BR conv -Instructs version 3.6 reiserfs software to mount a version 3.5 filesystem, -using the 3.6 format for newly created objects. This filesystem will no -longer be compatible with reiserfs 3.5 tools. -.TP -.BR hash= { rupasov | tea | r5 | 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 filesystem 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 filesystem being mounted, and to write this information into -the reiserfs superblock. This is only useful on the first mount of -an old format filesystem. -.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 journaling. 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 journaling -operations, save for actual writes into its journaling 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 filesystem. 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. -.TP -.BR barrier=none " / " barrier=flush " -This enables/disables the use of write barriers in the journaling code. -barrier=none disables it, barrier=flush enables it. Write barriers enforce -proper on-disk ordering of journal commits, making volatile disk write caches -safe to use, at some performance penalty. The reiserfs filesystem does not -enable write barriers by default. Be sure to enable barriers unless your disks -are battery-backed one way or another. Otherwise you risk filesystem -corruption in case of power failure. - -.SH "Mount options for romfs" -None. - -.SH "Mount options for squashfs" -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" -.TP -.BI size= nbytes -Override default maximum size of the filesystem. -The size is given in bytes, and rounded up to entire pages. -The default is half of the memory. The size parameter also accepts a suffix % -to limit this tmpfs instance to that percentage of your physical RAM: -the default, when neither size nor nr_blocks is specified, is size=50% -.TP -.B nr_blocks= -The same as size, but in blocks of PAGE_CACHE_SIZE -.TP -.B nr_inodes= -The maximum number of inodes for this instance. The default -is half of the number of your physical RAM pages, or (on a -machine with highmem) the number of lowmem RAM pages, -whichever is the lower. -.PP -The tmpfs mount options for sizing ( -.BR size , -.BR nr_blocks , -and -.BR nr_inodes ) -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 -.B mode= -Set initial permissions of the root directory. -.TP -.B uid= -The user id. -.TP -.B gid= -The group id. -.TP -.B mpol=[default|prefer:Node|bind:NodeList|interleave|interleave:NodeList] -Set the NUMA memory allocation policy for all files in that -instance (if the kernel CONFIG_NUMA is enabled) - which can be adjusted on the -fly via 'mount -o remount ...' -.RS -.TP -.B default -prefers to allocate memory from the local node -.TP -.B prefer:Node -prefers to allocate memory from the given Node -.TP -.B bind:NodeList -allocates memory only from nodes in NodeList -.TP -.B interleave -prefers to allocate from each node in turn -.TP -.B interleave:NodeList -allocates from each node of NodeList in turn. -.PP -The NodeList format is a comma-separated list of decimal numbers and ranges, a -range being two hyphen-separated decimal numbers, the smallest and largest node -numbers in the range. For example, mpol=bind:0-3,5,7,9-15 - -Note that trying to mount a tmpfs with an mpol option will fail if the -running kernel does not support NUMA; and will fail if its nodelist -specifies a node which is not online. If your system relies on that -tmpfs being mounted, but from time to time runs a kernel built without -NUMA capability (perhaps a safe recovery kernel), or with fewer nodes -online, then it is advisable to omit the mpol option from automatic -mount options. It can be added later, when the tmpfs is already mounted -on MountPoint, by 'mount -o remount,mpol=Policy:NodeList MountPoint'. - -.SH "Mount options for ubifs" -UBIFS is a flash file system which works on top of UBI volumes. Note that -.B -atime -is not supported and is always turned off. -.TP -The device name may be specified as -.RS -.B ubiX_Y -UBI device number -.BR X , -volume number -.B Y -.TP -.B ubiY -UBI device number -.BR 0 , -volume number -.B Y -.TP -.B ubiX:NAME -UBI device number -.BR X , -volume with name -.B NAME -.TP -.B ubi:NAME -UBI device number -.BR 0 , -volume with name -.B NAME -.RE -Alternative -.B ! -separator may be used instead of -.BR : . -.TP -The following mount options are available: -.TP -.BR bulk_read -Enable bulk-read. VFS read-ahead is disabled because it slows down the file -system. Bulk-Read is an internal optimization. Some flashes may read faster if -the data are read at one go, rather than at several read requests. For -example, OneNAND can do "read-while-load" if it reads more than one NAND page. -.TP -.BR no_bulk_read -Do not bulk-read. This is the default. -.TP -.BR chk_data_crc -Check data CRC-32 checksums. This is the default. -.TP -.BR no_chk_data_crc. -Do not check data CRC-32 checksums. With this option, the filesystem does not -check CRC-32 checksum for data, but it does check it for the internal indexing -information. This option only affects reading, not writing. CRC-32 is always -calculated when writing the data. -.TP -.BR compr= { none | lzo | zlib } -Select the default compressor which is used when new files are written. It is -still possible to read compressed files if mounted with the -.B none -option. - -.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 filesystem 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 ufs2 -Used in FreeBSD 5.x supported as read-write. -.TP -.B 5xbsd -Synonym for ufs2. -.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 -.RB [ 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. -This option is obsolete. -.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 enabled for the filesystem with this option or disabled -with utf8=0, utf8=no or utf8=false. If `uni_xlate' gets set, UTF8 gets -disabled. -.TP -.BR 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. This mode is the default since Linux 2.6.32. -.RE - - -.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 filesystem -(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 -filesystem (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 enabled) 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 -.BR grpid | bsdgroups " and " nogrpid | sysvgroups -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 any recent kernel. -.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 any recent kernel is 32768. -.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 filesystems using the filesystem uuid. -This is useful to mount LVM snapshot volumes. -.TP -.B osyncisosync -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 -.RS -.sp -.B "mount /tmp/disk.img /mnt -t vfat -o loop=/dev/loop" -.sp -.RE -will set up the loop device -.I /dev/loop3 -to correspond to the file -.IR /tmp/disk.img , -and then mount this device on -.IR /mnt . - -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, for example -.RS -.sp -.B "mount /tmp/disk.img /mnt -o loop" -.sp -.RE -The mount command -.B automatically -creates a loop device from a regular file if a filesystem type is -not specified or the filesystem is known for libblkid, for example: -.RS -.sp -.B "mount /tmp/disk.img /mnt" -.sp -.B "mount -t ext3 /tmp/disk.img /mnt" -.sp -.RE -This type of mount knows about three options, namely -.BR loop ", " offset ", " sizelimit " , -that are really options to -.BR \%losetup (8). -(These options can be used in addition to those specific -to the filesystem type.) - -Since Linux 2.6.25 is supported auto-destruction of loop devices and -then any loop device allocated by -.B mount -will be freed by -.B umount -independently on -.IR /etc/mtab . - -You can also free a loop device by hand, using `losetup -d' or `umount -d`. - -.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: - -.RS -.BI /sbin/mount. <suffix> -.I spec dir -.RB [ \-sfnv ] -.RB [ \-o -.IR options ] -.RB [ \-t -.IR type.subtype ] -.RE - -where the <type> is filesystem type and \-sfnvo options have same meaning like -standard mount options. The \-t option is used for filesystems with subtypes -support (for example /sbin/mount.fuse -t fuse.sshfs). - -.SH FILES -.TP 18n -.I /etc/fstab -filesystem table -.TP -.I /etc/mtab -table of mounted filesystems -.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 filesystem to cause a crash. -.PP -Some Linux filesystems don't support -.B "\-o sync and \-o dirsync" -(the ext2, ext3, fat and vfat filesystems -.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 package and is available from -ftp://ftp.kernel.org/pub/linux/utils/util-linux/. |