ntfs-3g(8) - man - phpman

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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 trans‐
parently compressed files; it can handle special files like symbolic links, devices, and FI‐
FOs; 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 order to avoid inconsis‐
tencies. Moreover, the fast restart feature available on recent Windows systems has to be
disabled. This can be achieved by issuing as an Administrator the Windows command which dis‐
ables both hibernation and fast restarting :

powercfg /h off

If either Windows is hibernated or its fast restart is enabled, partitions 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, execution and directory browsing permissions.
You can also assign permissions to a single user by using the uid and/or the gid options to‐
gether 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 permis‐
sions features as defined by POSIX. Moreover, by defining a Windows-to-Linux user mapping,
the ownerships and permissions 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 portabil‐
ity and interoperability reasons. This means that filenames are case sensitive and all char‐
acters are allowed except '/' and '\0'. This is perfectly legal on Windows, though some ap‐
plication may get confused. The option windows_names may be used to apply Windows restric‐
tions 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 de‐
fault, 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 example:

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 access control. This op‐
tion 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 access to the user mount‐
ing 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 opera‐
tions 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 inode access times rela‐
tive 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 option
doesn't break applications that need to know if a file has been read since the last
time it was modified. This is the default 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 sys‐
tem 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 Windows attribute. In such a directory, new files are created com‐
pressed and new subdirectories are themselves marked for compression. 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 appar‐
ent size of files and the behavior of read and write operation so that encrypted files
can be saved and restored without being decrypted. The user.ntfs.efsinfo extended at‐
tribute 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 ap‐
pear in directory listings, 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 di‐
rectories 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 direc‐
tories remain accessible by full name, for example you can always display the Windows
trash bin directory by : "ls -ld '$RECYCLE.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 locale environment. It is
however discouraged as it leads to files with untranslatable characters to not be vis‐
ible.

max_read=value
With this option the maximum size of read operations can be set. The default is infi‐
nite. 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 mount‐
ing on non-empty directories) were set, and no_def_opts cancels these default options.

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 access control. This op‐
tion 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 specifi‐
cations. 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 Windows and shutdown it properly, or use this
option which will remove the Windows hibernation file. Please note, this means that
the saved Windows session will be completely lost. Use this option under your own re‐
sponsibility.

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 option is specified, "$MFT" may not be visible due to a glibc bug.
Furthermore, irrespectively of show_sys_files, all files are accessible by name, for
example you can always do "ls -l '$UpCase'".

silent Do nothing, without returning any error, on chmod and chown operations and on permis‐
sion checking errors, when the permissions option is not set and no user mapping file
is defined. This option 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 device). The mode can be interix or wsl, and
existing files in either mode are recognized irrespective of the selected mode. In‐
terix is the traditional mode, used by default, and wsl is interoperable with Windows
WSL, but it is not compatible with Windows versions earlier than Windows 10. Neither
mode are interoperable 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 default .NTFS-3G/UserMap‐‐
ping. If file-name defines a full path, the file must be located on a partition previ‐
ously 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 mapping 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 sepa‐
rated by colons. The first field identifies a uid, the second field identifies a gid and the
third one identifies the corresponding NTFS id, known as a SID. The uid and the gid are op‐
tional 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 resulting 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 sys‐
tem 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 error 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 develop‐
ment 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 improvements were made, the ntfs-3g project was
initiated and currently led by long time Linux-NTFS team developer Szabolcs Szakacsits
(szaka AT 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 Altaparmakov, Jean-Pierre André, Erik Larsson,
Richard Russon, Szabolcs Szakacsits, Yura Pakhuchiy, Yuval Fledel, and the author of the
groundbreaking FUSE filesystem development framework, Miklos Szeredi.

SEE ALSO
ntfs-3g.probe(8), ntfsprogs(8), attr(5), getfattr(1)

ntfs-3g 2021.8.22 Aug 2021 NTFS-3G(8)