смонтировать файловую систему (mount a filesystem)
FILESYSTEM-SPECIFIC MOUNT OPTIONS
This section lists options that are specific to particular
filesystems. Where possible, you should first consult
filesystem-specific manual pages for details. Some of those pages
are listed in the following table.
┌─────────────────┬───────────────┐
│ │ │
│Filesystem(s) │ Manual page │
├─────────────────┼───────────────┤
│ │ │
│btrfs │ btrfs(5) │
├─────────────────┼───────────────┤
│ │ │
│cifs │ mount.cifs(8) │
├─────────────────┼───────────────┤
│ │ │
│ext2, ext3, ext4 │ ext4(5) │
├─────────────────┼───────────────┤
│ │ │
│fuse │ fuse(8) │
├─────────────────┼───────────────┤
│ │ │
│nfs │ nfs(5) │
├─────────────────┼───────────────┤
│ │ │
│tmpfs │ tmpfs(5) │
├─────────────────┼───────────────┤
│ │ │
│xfs │ xfs(5) │
└─────────────────┴───────────────┘
Note that some of the pages listed above might be available only
after you install the respective userland tools.
The following options apply only to certain filesystems. We sort
them by filesystem. All options follow the -o flag.
What options are supported depends a bit on the running kernel.
Further information may be available in filesystem-specific files
in the kernel source subdirectory Documentation/filesystems.
Mount options for adfs
uid=value and gid=value
Set the owner and group of the files in the filesystem
(default: uid=gid=0).
ownmask=value and othmask=value
Set the permission mask for ADFS 'owner' permissions and
'other' permissions, respectively (default: 0700 and 0077,
respectively). See also
/usr/src/linux/Documentation/filesystems/adfs.rst.
Mount options for affs
uid=value and gid=value
Set the owner and group of the root of the filesystem
(default: uid=gid=0, but with option uid or gid without
specified value, the UID and GID of the current process are
taken).
setuid=value and setgid=value
Set the owner and group of all files.
mode=value
Set the mode of all files to value & 0777 disregarding the
original permissions. Add search permission to directories
that have read permission. The value is given in octal.
protect
Do not allow any changes to the protection bits on the
filesystem.
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...
verbose
Print an informational message for each successful mount.
prefix=string
Prefix used before volume name, when following a link.
volume=string
Prefix (of length at most 30) used before '/' when following
a symbolic link.
reserved=value
(Default: 2.) Number of unused blocks at the start of the
device.
root=value
Give explicitly the location of the root block.
bs=value
Give blocksize. Allowed values are 512, 1024, 2048, 4096.
grpquota|noquota|quota|usrquota
These options are accepted but ignored. (However, quota
utilities may react to such strings in /etc/fstab.)
Mount options for debugfs
The debugfs filesystem is a pseudo filesystem, traditionally
mounted on /sys/kernel/debug. As of kernel version 3.4, debugfs
has the following options:
uid=n, gid=n
Set the owner and group of the mountpoint.
mode=value
Sets the mode of the mountpoint.
Mount options for devpts
The devpts filesystem is a pseudo filesystem, traditionally
mounted on /dev/pts. In order to acquire a pseudo terminal, a
process opens /dev/ptmx; the number of the pseudo terminal is
then made available to the process and the pseudo terminal slave
can be accessed as /dev/pts/<number>.
uid=value and gid=value
This sets the owner or the group of newly created pseudo
terminals 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 gid=5
will cause newly created pseudo terminals to belong to the
tty group.
mode=value
Set the mode of newly created pseudo terminals to the
specified value. The default is 0600. A value of mode=620 and
gid=5 makes "mesg y" the default on newly created pseudo
terminals.
newinstance
Create a private instance of the devpts filesystem, such that
indices of pseudo terminals allocated in this new instance
are independent of indices created in other instances of
devpts.
All mounts of devpts without this newinstance option share
the same set of pseudo terminal indices (i.e., legacy mode).
Each mount of devpts with the newinstance option has a
private set of pseudo terminal 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, /dev/ptmx must be a symbolic
link to pts/ptmx. See Documentation/filesystems/devpts.txt in
the Linux kernel source tree for details.
ptmxmode=value
Set the mode for the new ptmx device node in the devpts
filesystem.
With the support for multiple instances of devpts (see
newinstance option above), each instance has a private ptmx
node in the root of the devpts filesystem (typically
/dev/pts/ptmx).
For compatibility with older versions of the kernel, the
default mode of the new ptmx node is 0000. ptmxmode=value
specifies a more useful mode for the ptmx node and is highly
recommended when the 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.
Mount options for fat
(Note: fat is not a separate filesystem, but a common part of the
msdos, umsdos and vfat filesystems.)
blocksize={512|1024|2048}
Set blocksize (default 512). This option is obsolete.
uid=value and gid=value
Set the owner and group of all files. (Default: the UID and
GID of the current process.)
umask=value
Set the umask (the bitmask of the permissions that are not
present). The default is the umask of the current process.
The value is given in octal.
dmask=value
Set the umask applied to directories only. The default is the
umask of the current process. The value is given in octal.
fmask=value
Set the umask applied to regular files only. The default is
the umask of the current process. The value is given in
octal.
allow_utime=value
This option controls the permission check of mtime/atime.
20
If current process is in group of file's group ID, you
can change timestamp.
2
Other users can change timestamp.
The default is set from 'dmask' option. (If the directory is
writable, utime(2) is also allowed. I.e. ~dmask & 022)
Normally utime(2) checks that the current process is owner of the
file, or that it has the CAP_FOWNER capability. But FAT
filesystems don't have UID/GID on disk, so the normal check is
too inflexible. With this option you can relax it.
check=value
Three different levels of pickiness can be chosen:
r[elaxed]
Upper and lower case are accepted and equivalent, long
name parts are truncated (e.g. verylongname.foobar
becomes verylong.foo), leading and embedded spaces are
accepted in each name part (name and extension).
n[ormal]
Like "relaxed", but many special characters (*, ?, <,
spaces, etc.) are rejected. This is the default.
s[trict]
Like "normal", but names that contain long parts or
special characters that are sometimes used on Linux but
are not accepted by MS-DOS (+, =, etc.) are rejected.
codepage=value
Sets the codepage for converting to shortname characters on
FAT and VFAT filesystems. By default, codepage 437 is used.
conv=mode
This option is obsolete and may fail or be ignored.
cvf_format=module
Forces the driver to use the CVF (Compressed Volume File)
module cvf__module_ instead of auto-detection. If the kernel
supports kmod, the cvf_format=xxx option also controls
on-demand CVF module loading. This option is obsolete.
cvf_option=option
Option passed to the CVF module. This option is obsolete.
debug
Turn on the 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).
discard
If set, causes discard/TRIM commands to be issued to the
block device when blocks are freed. This is useful for SSD
devices and sparse/thinly-provisioned LUNs.
dos1xfloppy
If set, use a fallback default BIOS Parameter Block
configuration, determined by backing device size. These
static parameters match defaults assumed by DOS 1.x for 160
kiB, 180 kiB, 320 kiB, and 360 kiB floppies and floppy
images.
errors={panic|continue|remount-ro}
Specify FAT behavior on critical errors: panic, continue
without doing anything, or remount the partition in read-only
mode (default behavior).
fat={12|16|32}
Specify a 12, 16 or 32 bit fat. This overrides the automatic
FAT type detection routine. Use with caution!
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.
nfs={stale_rw|nostale_ro}
Enable this only if you want to export the FAT filesystem
over NFS.
stale_rw: This option maintains an index (cache) of directory
inodes which is used by the nfs-related code to improve
look-ups. Full file operations (read/write) over NFS are
supported but with cache eviction at NFS server, this could
result in spurious ESTALE errors.
nostale_ro: This option bases the inode number and file
handle on the on-disk location of a file in the FAT directory
entry. This ensures that ESTALE will not be returned after a
file is evicted from the inode cache. However, it means that
operations such as rename, create and unlink could cause file
handles that previously pointed at one file to point at a
different file, potentially causing data corruption. For this
reason, this option also mounts the filesystem readonly.
To maintain backward compatibility, -o nfs is also accepted,
defaulting to stale_rw.
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.
time_offset=minutes
Set offset for conversion of timestamps from local time used
by FAT to UTC. I.e., minutes will be subtracted from each
timestamp to convert it to UTC used internally by Linux. This
is useful when the time zone set in the kernel via
settimeofday(2) is not the time zone used by the filesystem.
Note that this option still does not provide correct time
stamps in all cases in presence of DST - time stamps in a
different DST setting will be off by one hour.
quiet
Turn on the quiet flag. Attempts to chown or chmod files do
not return errors, although they fail. Use with caution!
rodir
FAT has the ATTR_RO (read-only) attribute. On Windows, the
ATTR_RO of the directory will just be ignored, and is used
only by applications as a flag (e.g. it's set for the
customized folder).
If you want to use ATTR_RO as read-only flag even for the
directory, set this option.
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.
sys_immutable
If set, ATTR_SYS attribute on FAT is handled as IMMUTABLE
flag on Linux. Not set by default.
flush
If set, the filesystem will try to flush to disk more early
than normal. Not set by default.
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.
dots, nodots, dotsOK=[yes|no]
Various misguided attempts to force Unix or DOS conventions
onto a FAT filesystem.
Mount options for hfs
creator=cccc, type=cccc
Set the creator/type values as shown by the MacOS finder used
for creating new files. Default values: '????'.
uid=n, gid=n
Set the owner and group of all files. (Default: the UID and
GID of the current process.)
dir_umask=n, file_umask=n, umask=n
Set the umask used for all directories, all regular files, or
all files and directories. Defaults to the umask of the
current process.
session=n
Select the CDROM session to mount. Defaults to leaving that
decision to the CDROM driver. This option will fail with
anything but a CDROM as underlying device.
part=n
Select partition number n from the device. Only makes sense
for CDROMs. Defaults to not parsing the partition table at
all.
quiet
Don't complain about invalid mount options.
Mount options for hpfs
uid=value and gid=value
Set the owner and group of all files. (Default: the UID and
GID of the current process.)
umask=value
Set the umask (the bitmask of the permissions that are not
present). The default is the umask of the current process.
The value is given in octal.
case={lower|asis}
Convert all files names to lower case, or leave them.
(Default: case=lower.)
conv=mode
This option is obsolete and may fail or being ignored.
nocheck
Do not abort mounting when certain consistency checks fail.
Mount options for iso9660
ISO 9660 is a standard describing a filesystem structure to be
used on CD-ROMs. (This filesystem type is also seen on some DVDs.
See also the udf filesystem.)
Normal iso9660 filenames appear in an 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).
norock
Disable the use of Rock Ridge extensions, even if available.
Cf. map.
nojoliet
Disable the use of Microsoft Joliet extensions, even if
available. Cf. map.
check={r[elaxed]|s[trict]}
With check=relaxed, a filename is first converted to lower
case before doing the lookup. This is probably only
meaningful together with norock and map=normal. (Default:
check=strict.)
uid=value and gid=value
Give all files in the filesystem the indicated user or group
id, possibly overriding the information found in the Rock
Ridge extensions. (Default: uid=0,gid=0.)
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 map=off no name translation is
done. See norock. (Default: map=normal.) map=acorn is like
map=normal but also apply Acorn extensions if present.
mode=value
For non-Rock Ridge volumes, give all files the indicated
mode. (Default: read and execute permission for everybody.)
Octal mode values require a leading 0.
unhide
Also show hidden and associated files. (If the ordinary files
and the associated or hidden files have the same filenames,
this may make the ordinary files inaccessible.)
block={512|1024|2048}
Set the block size to the indicated value. (Default:
block=1024.)
conv=mode
This option is obsolete and may fail or being ignored.
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
16 MB.
session=x
Select number of session on a multisession CD.
sbsector=xxx
Session begins from sector xxx.
The following options are the same as for vfat and specifying
them only makes sense when using discs encoded using Microsoft's
Joliet extensions.
iocharset=value
Character set to use for converting 16 bit Unicode characters
on CD to 8 bit characters. The default is iso8859-1.
utf8
Convert 16 bit Unicode characters on CD to UTF-8.
Mount options for jfs
iocharset=name
Character set to use for converting from Unicode to ASCII.
The default is to do no conversion. Use iocharset=utf8 for
UTF8 translations. This requires CONFIG_NLS_UTF8 to be set in
the kernel .config file.
resize=value
Resize the volume to value blocks. JFS only supports growing
a volume, not shrinking it. This option is only valid during
a remount, when the volume is mounted read-write. The resize
keyword with no value will grow the volume to the full size
of the partition.
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.
integrity
Default. Commit metadata changes to the journal. Use this
option to remount a volume where the nointegrity option was
previously specified in order to restore normal behavior.
errors={continue|remount-ro|panic}
Define the behavior 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.)
noquota|quota|usrquota|grpquota
These options are accepted but ignored.
Mount options for msdos
See mount options for fat. If the 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.
Mount options for ncpfs
Just like nfs, the ncpfs implementation expects a binary argument
(a struct ncp_mount_data) to the mount system call. This argument
is constructed by ncpmount(8) and the current version of mount
(2.12) does not know anything about ncpfs.
Mount options for ntfs
iocharset=name
Character set to use when returning file names. Unlike VFAT,
NTFS suppresses names that contain nonconvertible characters.
Deprecated.
nls=name
New name for the option earlier called iocharset.
utf8
Use UTF-8 for converting file names.
uni_xlate={0|1|2}
For 0 (or 'no' or 'false'), do not use escape sequences for
unknown Unicode characters. For 1 (or 'yes' or 'true') or 2,
use vfat-style 4-byte escape sequences starting with ":".
Here 2 gives a little-endian encoding and 1 a byteswapped
bigendian encoding.
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.
uid=value, gid=value and umask=value
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.
Mount options for overlay
Since Linux 3.18 the overlay pseudo filesystem implements a union
mount for other filesystems.
An overlay filesystem combines two filesystems - an upper
filesystem and a lower filesystem. When a name exists in both
filesystems, the object in the upper filesystem is visible while
the object in the lower filesystem is either hidden or, in the
case of directories, merged with the upper object.
The lower filesystem can be any filesystem supported by Linux and
does not need to be writable. The lower filesystem can even be
another overlayfs. The upper filesystem will normally be writable
and if it is it must support the creation of trusted.* extended
attributes, and must provide a valid d_type in readdir responses,
so NFS is not suitable.
A read-only overlay of two read-only filesystems may use any
filesystem type. The options lowerdir and upperdir are combined
into a merged directory by using:
mount -t overlay overlay \
-olowerdir=/lower,upperdir=/upper,workdir=/work /merged
lowerdir=directory
Any filesystem, does not need to be on a writable filesystem.
upperdir=directory
The upperdir is normally on a writable filesystem.
workdir=directory
The workdir needs to be an empty directory on the same
filesystem as upperdir.
userxattr
Use the "user.overlay." xattr namespace instead of
"trusted.overlay.". This is useful for unprivileged mounting
of overlayfs.
redirect_dir={on|off|follow|nofollow}
If the redirect_dir feature is enabled, then the directory
will be copied up (but not the contents). Then the
"{trusted|user}.overlay.redirect" extended attribute is set
to the path of the original location from the root of the
overlay. Finally the directory is moved to the new location.
on
Redirects are enabled.
off
Redirects are not created and only followed if
"redirect_always_follow" feature is enabled in the
kernel/module config.
follow
Redirects are not created, but followed.
nofollow
Redirects are not created and not followed (equivalent to
"redirect_dir=off" if "redirect_always_follow" feature is
not enabled).
index={on|off}
Inode index. If this feature is disabled and a file with
multiple hard links is copied up, then this will "break" the
link. Changes will not be propagated to other names referring
to the same inode.
uuid={on|off}
Can be used to replace UUID of the underlying filesystem in
file handles with null, and effectively disable UUID checks.
This can be useful in case the underlying disk is copied and
the UUID of this copy is changed. This is only applicable if
all lower/upper/work directories are on the same filesystem,
otherwise it will fallback to normal behaviour.
nfs_export={on|off}
When the underlying filesystems supports NFS export and the
"nfs_export" feature is enabled, an overlay filesystem may be
exported to NFS.
With the 'nfs_export' feature, on copy_up of any lower
object, an index entry is created under the index directory.
The index entry name is the hexadecimal representation of the
copy up origin file handle. For a non-directory object, the
index entry is a hard link to the upper inode. For a
directory object, the index entry has an extended attribute
"{trusted|user}.overlay.upper" with an encoded file handle of
the upper directory inode.
When encoding a file handle from an overlay filesystem
object, the following rules apply
• For a non-upper object, encode a lower file handle
from lower inode
• For an indexed object, encode a lower file handle
from copy_up origin
• For a pure-upper object and for an existing
non-indexed upper object, encode an upper file handle
from upper inode
The encoded overlay file handle includes
• Header including path type information (e.g.
lower/upper)
• UUID of the underlying filesystem
• Underlying filesystem encoding of underlying inode
This encoding format is identical to the encoding format file
handles that are stored in extended attribute
"{trusted|user}.overlay.origin". When decoding an overlay
file handle, the following steps are followed
• Find underlying layer by UUID and path type
information.
• Decode the underlying filesystem file handle to
underlying dentry.
• For a lower file handle, lookup the handle in index
directory by name.
• If a whiteout is found in index, return ESTALE. This
represents an overlay object that was deleted after
its file handle was encoded.
• For a non-directory, instantiate a disconnected
overlay dentry from the decoded underlying dentry,
the path type and index inode, if found.
• For a directory, use the connected underlying decoded
dentry, path type and index, to lookup a connected
overlay dentry.
Decoding a non-directory file handle may return a
disconnected dentry. copy_up of that disconnected dentry will
create an upper index entry with no upper alias.
When overlay filesystem has multiple lower layers, a middle
layer directory may have a "redirect" to lower directory.
Because middle layer "redirects" are not indexed, a lower
file handle that was encoded from the "redirect" origin
directory, cannot be used to find the middle or upper layer
directory. Similarly, a lower file handle that was encoded
from a descendant of the "redirect" origin directory, cannot
be used to reconstruct a connected overlay path. To mitigate
the cases of directories that cannot be decoded from a lower
file handle, these directories are copied up on encode and
encoded as an upper file handle. On an overlay filesystem
with no upper layer this mitigation cannot be used NFS export
in this setup requires turning off redirect follow (e.g.
"redirect_dir=nofollow").
The overlay filesystem does not support non-directory
connectable file handles, so exporting with the subtree_check
exportfs configuration will cause failures to lookup files
over NFS.
When the NFS export feature is enabled, all directory index
entries are verified on mount time to check that upper file
handles are not stale. This verification may cause
significant overhead in some cases.
Note: the mount options index=off,nfs_export=on are
conflicting for a read-write mount and will result in an
error.
xinfo={on|off|auto}
The "xino" feature composes a unique object identifier from
the real object st_ino and an underlying fsid index. The
"xino" feature uses the high inode number bits for fsid,
because the underlying filesystems rarely use the high inode
number bits. In case the underlying inode number does
overflow into the high xino bits, overlay filesystem will
fall back to the non xino behavior for that inode.
For a detailed description of the effect of this option
please refer to
https://www.kernel.org/doc/html/latest/filesystems/overlayfs.html?highlight=overlayfs
metacopy={on|off}
When metadata only copy up feature is enabled, overlayfs will
only copy up metadata (as opposed to whole file), when a
metadata specific operation like chown/chmod is performed.
Full file will be copied up later when file is opened for
WRITE operation.
In other words, this is delayed data copy up operation and
data is copied up when there is a need to actually modify
data.
volatile
Volatile mounts are not guaranteed to survive a crash. It is
strongly recommended that volatile mounts are only used if
data written to the overlay can be recreated without
significant effort.
The advantage of mounting with the "volatile" option is that
all forms of sync calls to the upper filesystem are omitted.
In order to avoid a giving a false sense of safety, the
syncfs (and fsync) semantics of volatile mounts are slightly
different than that of the rest of VFS. If any writeback
error occurs on the upperdir's filesystem after a volatile
mount takes place, all sync functions will return an error.
Once this condition is reached, the filesystem will not
recover, and every subsequent sync call will return an error,
even if the upperdir has not experience a new error since the
last sync call.
When overlay is mounted with "volatile" option, the directory
"$workdir/work/incompat/volatile" is created. During next
mount, overlay checks for this directory and refuses to mount
if present. This is a strong indicator that user should throw
away upper and work directories and create fresh one. In very
limited cases where the user knows that the system has not
crashed and contents of upperdir are intact, The "volatile"
directory can be removed.
Mount options for reiserfs
Reiserfs is a journaling filesystem.
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.
hash={rupasov|tea|r5|detect}
Choose which hash function reiserfs will use to find files
within directories.
rupasov
A hash invented by Yury Yu. Rupasov. It is fast and
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.
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.
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.
detect
Instructs 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.
hashed_relocation
Tunes the block allocator. This may provide performance
improvements in some situations.
no_unhashed_relocation
Tunes the block allocator. This may provide performance
improvements in some situations.
noborder
Disable the border allocator algorithm invented by Yury Yu.
Rupasov. This may provide performance improvements in some
situations.
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 nolog is a work in progress.
notail
By default, reiserfs stores small files and 'file tails'
directly into its tree. This confuses some utilities such as
lilo(8). This option is used to disable packing of files into
the tree.
replayonly
Replay the transactions which are in the journal, but do not
actually mount the filesystem. Mainly used by reiserfsck.
resize=number
A remount option which permits online expansion of reiserfs
partitions. Instructs reiserfs to assume that the device has
number blocks. This option is designed for use with devices
which are under logical volume management (LVM). There is a
special resizer utility which can be obtained from
ftp://ftp.namesys.com/pub/reiserfsprogs.
user_xattr
Enable Extended User Attributes. See the attr(1) manual page.
acl
Enable POSIX Access Control Lists. See the acl(5) manual
page.
barrier=none / barrier=flush
This disables / enables the use of write barriers in the
journaling code. barrier=none disables, barrier=flush enables
(default). This also requires an IO stack which can support
barriers, and if reiserfs gets an error on a barrier write,
it will disable barriers 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.
Mount options for ubifs
UBIFS is a flash filesystem which works on top of UBI volumes.
Note that atime is not supported and is always turned off.
The device name may be specified as
ubiX_Y
UBI device number X, volume number Y
ubiY
UBI device number 0, volume number Y
ubiX:NAME
UBI device number X, volume with name NAME
ubi:NAME
UBI device number 0, volume with name NAME
Alternative ! separator may be used instead of :.
The following mount options are available:
bulk_read
Enable bulk-read. VFS read-ahead is disabled because it slows
down the filesystem. 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.
no_bulk_read
Do not bulk-read. This is the default.
chk_data_crc
Check data CRC-32 checksums. This is the default.
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.
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 none option.
Mount options for udf
UDF is the "Universal Disk Format" filesystem defined by OSTA,
the Optical Storage Technology Association, and is often used for
DVD-ROM, frequently in the form of a hybrid UDF/ISO-9660
filesystem. It is, however, perfectly usable by itself on disk
drives, flash drives and other block devices. See also iso9660.
uid=
Make all files in the filesystem belong to the given user.
uid=forget can be specified independently of (or usually in
addition to) uid=<user> and results in UDF not storing uids
to the media. In fact the recorded uid is the 32-bit overflow
uid -1 as defined by the UDF standard. The value is given as
either <user> which is a valid user name or the corresponding
decimal user id, or the special string "forget".
gid=
Make all files in the filesystem belong to the given group.
gid=forget can be specified independently of (or usually in
addition to) gid=<group> and results in UDF not storing gids
to the media. In fact the recorded gid is the 32-bit overflow
gid -1 as defined by the UDF standard. The value is given as
either <group> which is a valid group name or the
corresponding decimal group id, or the special string
"forget".
umask=
Mask out the given permissions from all inodes read from the
filesystem. The value is given in octal.
mode=
If mode= is set the permissions of all non-directory inodes
read from the filesystem will be set to the given mode. The
value is given in octal.
dmode=
If dmode= is set the permissions of all directory inodes read
from the filesystem will be set to the given dmode. The value
is given in octal.
bs=
Set the block size. Default value prior to kernel version
2.6.30 was 2048. Since 2.6.30 and prior to 4.11 it was
logical device block size with fallback to 2048. Since 4.11
it is logical block size with fallback to any valid block
size between logical device block size and 4096.
For other details see the mkudffs(8) 2.0+ manpage, sections
COMPATIBILITY and BLOCK SIZE.
unhide
Show otherwise hidden files.
undelete
Show deleted files in lists.
adinicb
Embed data in the inode. (default)
noadinicb
Don't embed data in the inode.
shortad
Use short UDF address descriptors.
longad
Use long UDF address descriptors. (default)
nostrict
Unset strict conformance.
iocharset=
Set the NLS character set. This requires kernel compiled with
CONFIG_UDF_NLS option.
utf8
Set the UTF-8 character set.
Mount options for debugging and disaster recovery
novrs
Ignore the Volume Recognition Sequence and attempt to mount
anyway.
session=
Select the session number for multi-session recorded optical
media. (default= last session)
anchor=
Override standard anchor location. (default= 256)
lastblock=
Set the last block of the filesystem.
Unused historical mount options that may be encountered and should be
removed
uid=ignore
Ignored, use uid=<user> instead.
gid=ignore
Ignored, use gid=<group> instead.
volume=
Unimplemented and ignored.
partition=
Unimplemented and ignored.
fileset=
Unimplemented and ignored.
rootdir=
Unimplemented and ignored.
Mount options for ufs
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:
old
Old format of ufs, this is the default, read only. (Don't
forget to give the -r option.)
44bsd
For filesystems created by a BSD-like system (NetBSD,
FreeBSD, OpenBSD).
ufs2
Used in FreeBSD 5.x supported as read-write.
5xbsd
Synonym for ufs2.
sun
For filesystems created by SunOS or Solaris on Sparc.
sunx86
For filesystems created by Solaris on x86.
hp
For filesystems created by HP-UX, read-only.
nextstep
For filesystems created by NeXTStep (on NeXT station)
(currently read only).
nextstep-cd
For NextStep CDROMs (block_size == 2048), read-only.
openstep
For filesystems created by OpenStep (currently read
only). The same filesystem type is also used by Mac OS X.
onerror=value
Set behavior on error:
panic
If an error is encountered, cause a kernel panic.
[lock|umount|repair]
These mount options don't do anything at present; when an
error is encountered only a console message is printed.
Mount options for umsdos
See mount options for msdos. The dotsOK option is explicitly
killed by umsdos.
Mount options for vfat
First of all, the mount options for fat are recognized. The
dotsOK option is explicitly killed by vfat. Furthermore, there
are
uni_xlate
Translate unhandled Unicode characters to special escaped
sequences. This lets you backup and restore filenames that
are created with any Unicode characters. Without this option,
a '?' is used when no translation is possible. The escape
character is ':' because it is otherwise invalid on the vfat
filesystem. The escape sequence that gets used, where u is
the Unicode character, is: ':', (u & 0x3f), ((u>>6) & 0x3f),
(u>>12).
posix
Allow two files with names that only differ in case. This
option is obsolete.
nonumtail
First try to make a short name without sequence number,
before trying name~num.ext.
utf8
UTF8 is the filesystem safe 8-bit encoding 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.
shortname=mode
Defines the behavior for creation and display of filenames
which fit into 8.3 characters. If a long name for a file
exists, it will always be the preferred one for display.
There are four modes:
lower
Force the short name to lower case upon display; store a
long name when the short name is not all upper case.
win95
Force the short name to upper case upon display; store a
long name when the short name is not all upper case.
winnt
Display the short name as is; store a long name when the
short name is not all lower case or all upper case.
mixed
Display the short name as is; store a long name when the
short name is not all upper case. This mode is the
default since Linux 2.6.32.
Mount options for usbfs
devuid=uid and devgid=gid and devmode=mode
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.
busuid=uid and busgid=gid and busmode=mode
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.
listuid=uid and listgid=gid and listmode=mode
Set the owner and group and mode of the file devices
(default: uid=gid=0, mode=0444). The mode is given in octal.
