NTFS-3G(8) System Manager's Manual NTFS-3G(8)
NAME
ntfs-3g - Third Generation Read/Write NTFS Driver
SYNOPSIS
ntfs-3g [-o option[,...]] volume mount_point
mount -t ntfs-3g [-o option[,...]] volume mount_point
lowntfs-3g [-o option[,...]] volume mount_point
mount -t lowntfs-3g [-o option[,...]] volume mount_point
DESCRIPTION
ntfs-3g is an NTFS driver, which can create, remove, rename, move
files, directories, hard links, and streams; it can read and write
files, including streams, sparse files and transparently compressed
files; it can handle special files like symbolic links, devices, and
FIFOs; moreover it provides standard management of file ownership and
permissions, including POSIX ACLs.
It comes in two variants ntfs-3g and lowntfs-3g with a few differences
mentioned below in relevant options descriptions.
The volume to be mounted can be either a block device or an image file,
either by using the mount command or starting the drive.
Windows hibernation and fast restarting
On computers which can be dual-booted into Windows or Linux, Windows
has to be fully shut down before booting into Linux, otherwise the NTFS
file systems on internal disks may be left in an inconsistent state and
changes made by Linux may be ignored by Windows.
So, Windows may not be left in hibernation when starting Linux, in or-
der to avoid inconsistencies. Moreover, the fast restart feature avail-
able on recent Windows systems has to be disabled. This can be achieved
by issuing as an Administrator the Windows command which disables both
hibernation and fast restarting :
powercfg /h off
If either Windows is hibernated or its fast restart is enabled, parti-
tions on internal disks are forced to be mounted in read-only mode.
Access Handling and Security
By default, files and directories are owned by the effective user and
group of the mounting process, and everybody has full read, write, exe-
cution and directory browsing permissions. You can also assign permis-
sions to a single user by using the uid and/or the gid options together
with the umask, or fmask and dmask options.
Doing so, all Windows users have full access to the files created by
ntfs-3g.
But, by setting the permissions option, you can benefit from the full
ownership and permissions features as defined by POSIX. Moreover, by
defining a Windows-to-Linux user mapping, the ownerships and permis-
sions are even applied to Windows users and conversely.
If ntfs-3g is set setuid-root then non-root users will be also able to
mount volumes.
Windows Filename Compatibility
NTFS supports several filename namespaces: DOS, Win32 and POSIX. While
the ntfs-3g driver handles all of them, it always creates new files in
the POSIX namespace for maximum portability and interoperability rea-
sons. This means that filenames are case sensitive and all characters
are allowed except '/' and '\0'. This is perfectly legal on Windows,
though some application may get confused. The option windows_names may
be used to apply Windows restrictions to new file names.
Alternate Data Streams (ADS)
NTFS stores all data in streams. Every file has exactly one unnamed
data stream and can have many named data streams. The size of a file
is the size of its unnamed data stream. By default, ntfs-3g will only
read the unnamed data stream.
By using the option streams_interface=windows, with the ntfs-3g driver
(not possible with lowntfs-3g), you will be able to read any named data
streams, simply by specifying the stream name after a colon. For exam-
ple:
cat some.mp3:artist
Named data streams act like normal files, so you can read from them,
write to them and even delete them (using rm). You can list all the
named data streams a file has by getting the ntfs.streams.list extended
attribute.
OPTIONS
Below is a summary of the options that ntfs-3g accepts.
acl Enable setting Posix ACLs on created files and use them for ac-
cess control. This option is only available on specific builds.
It is set by default when a user mapping file is present and the
permissions mount option is not set.
allow_other
This option overrides the security measure restricting file ac-
cess to the user mounting the filesystem. This option is only
allowed to root, but this restriction can be overridden by the
user_allow_other option in the /etc/fuse.conf file.
atime, noatime, relatime
The atime option updates inode access time for each access.
The noatime option disables inode access time updates, which can
speed up file operations and prevent sleeping (notebook) disks
spinning up too often thus saving energy and disk lifetime.
The relatime option is very similar to noatime. It updates in-
ode access times relative to modify or change time. The access
time is only updated if the previous access time was earlier
than the current modify or change time. Unlike noatime this op-
tion doesn't break applications that need to know if a file has
been read since the last time it was modified. This is the de-
fault behaviour.
big_writes
This option prevents fuse from splitting write buffers into 4K
chunks, enabling big write buffers to be transferred from the
application in a single step (up to some system limit, generally
128K bytes).
compression
This option enables creating new transparently compressed files
in directories marked for compression. A directory is marked for
compression by setting the bit 11 (value 0x00000800) in its Win-
dows attribute. In such a directory, new files are created com-
pressed and new subdirectories are themselves marked for com-
pression. The option and the flag have no effect on existing
files. Currently this is the default option.
debug Makes ntfs-3g (or lowntfs-3g) to print a lot of debug output
from libntfs-3g and FUSE.
delay_mtime[= value]
Only update the file modification time and the file change time
of a file when it is closed or when the indicated delay since
the previous update has elapsed. The argument is a number of
seconds, with a default value of 60. This is mainly useful for
big files which are kept open for a long time and written to
without changing their size, such as databases or file system
images mounted as loop.
dmask=value
Set the bitmask of the directory permissions that are not
present. The value is given in octal. The default value is 0
which means full access to everybody.
efs_raw
This option should only be used in backup or restore situation.
It changes the apparent size of files and the behavior of read
and write operation so that encrypted files can be saved and re-
stored without being decrypted. The user.ntfs.efsinfo extended
attribute has also to be saved and restored for the file to be
decrypted.
fmask=value
Set the bitmask of the file permissions that are not present.
The value is given in octal. The default value is 0 which means
full access to everybody.
force This option is obsolete. It has been superseded by the recover
and norecover options.
hide_dot_files
Set the hidden flag in the NTFS attribute for created files and
directories whose first character of the name is a dot. Such
files and directories normally do not appear in directory list-
ings, and when the flag is set they do not appear in Windows di-
rectory displays either. When a file is renamed or linked with
a new name, the hidden flag is adjusted to the latest name.
hide_hid_files
Hide the hidden files and directories in directory listings, the
hidden files and directories being the ones whose NTFS attribute
have the hidden flag set. The hidden files will not be selected
when using wildcards in commands, but all files and directories
remain accessible by full name, for example you can always dis-
play the Windows trash bin directory by : "ls -ld '$RECY-
CLE.BIN'".
ignore_case (only with lowntfs-3g)
Ignore character case when accessing a file (FOO, Foo, foo, etc.
designate the same file). All files are displayed with lower
case in directory listings.
inherit
When creating a new file, set its initial protections according
to inheritance rules defined in parent directory. These rules
deviate from Posix specifications, but yield a better Windows
compatibility. The permissions (or **acl**) option or a valid
user mapping file is required for this option to be effective.
locale=value
This option can be useful when wanting a language specific lo-
cale environment. It is however discouraged as it leads to
files with untranslatable characters to not be visible.
max_read=value
With this option the maximum size of read operations can be set.
The default is infinite. Note that the size of read requests is
limited anyway by the system (usually to 128kbyte).
no_def_opts
By default ntfs-3g acts as if silent (ignore permission errors
when permissions are not enabled), allow_other (allow any user
to access files) and nonempty (allow mounting on non-empty di-
rectories) were set, and no_def_opts cancels these default op-
tions.
no_detach
Makes ntfs-3g to not detach from terminal and print some debug
output.
nocompression
This option disables creating new transparently compressed files
in directories marked for compression. Existing compressed files
can still be read and updated.
norecover
Do not try to mount a partition which was not unmounted properly
by Windows.
permissions
Set standard permissions on created files and use standard ac-
cess control. This option is set by default when a user mapping
file is present.
posix_nlink
Compute the count of hard links of a file or directory according
to the POSIX specifications. When this option is not set, a
count of 1 is set for directories, and the short name of files
is accounted for. Using the option entails some penalty as the
count is not stored and has to be computed.
recover
Recover and try to mount a partition which was not unmounted
properly by Windows. The Windows logfile is cleared, which may
cause inconsistencies. Currently this is the default option.
remove_hiberfile
When the NTFS volume is hibernated, a read-write mount is denied
and a read-only mount is forced. One needs either to resume Win-
dows and shutdown it properly, or use this option which will re-
move the Windows hibernation file. Please note, this means that
the saved Windows session will be completely lost. Use this op-
tion under your own responsibility.
ro Mount the filesystem read-only. Useful if Windows is hibernated
or the NTFS journal file is unclean.
show_sys_files
Show the metafiles in directory listings. Otherwise the default
behaviour is to hide the metafiles, which are special files used
to store the NTFS structure. Please note that even when this op-
tion is specified, "$MFT" may not be visible due to a glibc bug.
Furthermore, irrespectively of show_sys_files, all files are ac-
cessible by name, for example you can always do "ls -l '$Up-
Case'".
silent Do nothing, without returning any error, on chmod and chown op-
erations and on permission checking errors, when the permissions
option is not set and no user mapping file is defined. This op-
tion is on by default, and when set off (through option
no_def_opts) ownership and permissions parameters have to be
set.
special_files=mode
This option selects a mode for representing a special file to be
created (symbolic link, socket, fifo, character or block de-
vice). The mode can be interix or wsl, and existing files in ei-
ther mode are recognized irrespective of the selected mode. In-
terix is the traditional mode, used by default, and wsl is in-
teroperable with Windows WSL, but it is not compatible with Win-
dows versions earlier than Windows 10. Neither mode are inter-
operable with Windows.
streams_interface=mode
This option controls how the user can access Alternate Data
Streams (ADS) or in other words, named data streams. The mode
can be set to one of none, windows or xattr. If the option is
set to none, the user will have no access to the named data
streams. If it is set to windows (not possible with lowntfs-3g),
then the user can access them just like in Windows (eg. cat
file:stream). If it's set to xattr, then the named data streams
are mapped to extended attributes and a user can manipulate them
using {get,set}fattr utilities. The default is xattr.
uid=value and gid=value
Set the owner and the group of files and directories. The values
are numerical. The defaults are the uid and gid of the current
process.
umask=value
Set the bitmask of the file and directory permissions that are
not present. The value is given in octal. The default value is 0
which means full access to everybody.
usermapping=file-name
Use file file-name as the user mapping file instead of the de-
fault .NTFS-3G/UserMapping. If file-name defines a full path,
the file must be located on a partition previously mounted. If
it defines a relative path, it is interpreted relative to the
root of NTFS partition being mounted.
When a user mapping file is defined, the options uid=, gid=,
umask=, fmask=, dmask= and silent are ignored.
user_xattr
Same as streams_interface=xattr.
windows_names
This option prevents files, directories and extended attributes
to be created with a name not allowed by windows, because
- it contains some not allowed character,
- or the last character is a space or a dot,
- or the name is reserved.
The forbidden characters are the nine characters " * / : < > ? \
| and those whose code is less than 0x20, and the reserved names
are CON, PRN, AUX, NUL, COM1..COM9, LPT1..LPT9, with no suffix
or followed by a dot.
Existing such files can still be read (and renamed).
USER MAPPING
NTFS uses specific ids to record the ownership of files instead of the
uid (user id) and gid (group id) used by Linux. As a consequence a map-
ping between the ids has to be defined for ownerships to be recorded
into NTFS files and recognized.
By default, this mapping is fetched from the file .NTFS-3G/UserMapping
located in the NTFS partition. The option usermapping= may be used to
define another location. When the option **permissions** is set and no
mapping file is found, a default mapping is used.
Each line in the user mapping file defines a mapping. It is organized
in three fields separated by colons. The first field identifies a uid,
the second field identifies a gid and the third one identifies the cor-
responding NTFS id, known as a SID. The uid and the gid are optional
and defining both of them for the same SID is not recommended.
If no interoperation with Windows is needed, you can use the option
permissions to define a standard mapping. Alternately, you may define
your own mapping by setting a single default mapping with no uid and
gid. In both cases, files created on Linux will appear to Windows as
owned by a foreign user, and files created on Windows will appear to
Linux as owned by root. Just copy the example below and replace the 9
and 10-digit numbers by any number not greater than 4294967295. The re-
sulting behavior is the same as the one with the option permission set
with no ownership option and no user mapping file available.
::S-1-5-21-3141592653-589793238-462643383-10000
If a strong interoperation with Windows is needed, the mapping has to
be defined for each user and group known to both system, and the SIDs
used by Windows has to be collected. This will lead to a user mapping
file like :
john::S-1-5-21-3141592653-589793238-462643383-1008
mary::S-1-5-21-3141592653-589793238-462643383-1009
:smith:S-1-5-21-3141592653-589793238-462643383-513
::S-1-5-21-3141592653-589793238-462643383-10000
The utility ntfsusermap may be used to create such a user mapping file.
EXAMPLES
Mount /dev/sda1 to /mnt/windows:
ntfs-3g /dev/sda1 /mnt/windows
or
mount -t ntfs-3g /dev/sda1 /mnt/windows
Mount the ntfs data partition /dev/sda3 to /mnt/data with standard
Linux permissions applied :
ntfs-3g -o permissions /dev/sda3 /mnt/data
or
mount -t ntfs-3g -o permissions /dev/sda3 /mnt/data
Read-only mount /dev/sda5 to /home/user/mnt and make user with uid 1000
to be the owner of all files:
ntfs-3g /dev/sda5 /home/user/mnt -o ro,uid=1000
/etc/fstab entry for the above (the sixth and last field has to be zero
to avoid a file system check at boot time) :
/dev/sda5 /home/user/mnt ntfs-3g ro,uid=1000 0 0
Unmount /mnt/windows:
umount /mnt/windows
EXIT CODES
To facilitate the use of the ntfs-3g driver in scripts, an exit code is
returned to give an indication of the mountability status of a volume.
Value 0 means success, and all other ones mean an error. The unique er-
ror codes are documented in the ntfs-3g.probe(8) manual page.
KNOWN ISSUES
Please see
https://github.com/tuxera/ntfs-3g/wiki/NTFS-3G-FAQ
for common questions and known issues. If you would find a new one in
the latest release of the software then please post an ntfs-3g issue
describing it in detail so that the development team can be aware of
the issue and take care of it:
https://github.com/tuxera/ntfs-3g/issues
AUTHORS
ntfs-3g was based on and a major improvement to ntfsmount and libntfs
which were written by Yura Pakhuchiy and the Linux-NTFS team. The im-
provements were made, the ntfs-3g project was initiated and currently
led by long time Linux-NTFS team developer Szabolcs Szakacsits
(szaka@tuxera.com).
THANKS
Several people made heroic efforts, often over five or more years which
resulted the ntfs-3g driver. Most importantly they are Anton Alta-
parmakov, Jean-Pierre André, Erik Larsson, Richard Russon, Szabolcs
Szakacsits, Yura Pakhuchiy, Yuval Fledel, and the author of the ground-
breaking FUSE filesystem development framework, Miklos Szeredi.
SEE ALSO
ntfs-3g.probe(8), ntfsprogs(8), attr(5), getfattr(1)
ntfs-3g 2022.10.3 Aug 2021 NTFS-3G(8)
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