NTFS-3G
Section: Maintenance Commands (8)
Updated: November 2009
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NAME
ntfs-3g - Third Generation Read/Write NTFS Driver
SYNOPSIS
ntfs-3g
volume mount_point
[-o option[,...]]
mount -t ntfs-3g
volume mount_point
[-o option[,...]]
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 and sparse files; it can handle special files like
symbolic links, devices, and FIFOs; moreover it can also read
and create transparently compressed files.
The volume to be mounted can be either a block device or
an image file.
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 together with the
umask,
or
fmask
and
dmask
options.
Doing so, Windows users have full access to the files created by
ntfs-3g.
But, by defining a Windows-to-Linux user mapping in the file
.NTFS-3G/UserMapping, you can benefit from the full ownership and
permissions features as defined by Posix and those ownership and
permissions will be 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 reasons.
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. If you find so then please report it
to the developer of the relevant Windows software.
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 options "streams_interface=windows", you will be able to read
any named data streams, simply by specifying the stream's 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.
- 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.
- 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.
- 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.
- usermapping=file-name
-
Use file file-name as the user mapping file instead of the default
.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 dsilent= are ignored.
- default_permissions
-
Use standard access control. This option requires either a user mapping
file to be present, or the options uid= and gid= of a user
to be defined. This option is set by default when a user mapping file
or an ownership related option is present.
- inherit
-
When creating a new file, set its initial ownership and protections
according to inheritance rules defined in parent directory. These rules
deviate from Posix specifications, but yield a better Windows
compatibility. A valid user mapping file is required for this option
to be effective.
- ro
-
Mount filesystem read-only. Useful if Windows is hibernated or the
NTFS journal file is unclean.
- 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 chars
to not be visible. Please see more information about this topic at
http://ntfs-3g.org/support.html#locale
- force
-
Force the mounting even if the NTFS logfile is unclean. The logfile
will be unconditionally cleared. Use this option with caution and for
your own responsibility.
- remove_hiberfile
-
Unlike in case of read-only mount, the read-write mount is denied if
the NTFS volume is hibernated. 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 for your own
responsibility.
- 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 inode 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 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.
- show_sys_files
-
Show the system files in directory listings.
Otherwise the default behaviour is to hide the system files.
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'".
- allow_other
-
This option overrides the security measure restricting file access
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.
- 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 to 32 pages (which is 128kbyte on i386).
- silent
-
Do nothing on chmod and chown operations, but do not return error
when the user mapping file required by these operations is not defined.
This option is on by default.
- no_def_opts
-
By default ntfs-3g acts as "silent" was passed to it,
this option cancel this behaviour.
- streams_interface=value
-
This option controls how the user can access Alternate Data Streams (ADS)
or in other words, named data streams. It 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's set
to windows, 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 xattrs and user can manipulate them using {get,set}fattr
utilities. The default is xattr.
- user_xattr
-
Same as streams_interface=xattr.
- 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 restored
without being decrypted. The user.ntfs.efsinfo extended attribute
has also to be saved and restored for the file to be decrypted.
- debug
-
Makes ntfs-3g to not detach from terminal and print a lot of debug output from
libntfs-3g and FUSE.
- no_detach
-
Same as above but with less debug output.
USER MAPPING
NTFS uses specific ids to record the ownership of files instead of
the uid and gid used by Linux. As a consequence a mapping
between the ids has to be defined for ownerships to be recorded into
NTFS 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.
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
corresponding 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, a single default mapping
with no uid and gid can be used. Just copy the example below and replace
the 9 and 10-digit numbers by any number not greater than 4294967295.
-
::S-1-5-21-3141592653-589793238-462643383-10000
If interoperation with Windows is needed, the mapping has to be defined
for each user and group known in 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 ntfs-3g.usermap may be used to create the 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
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:
-
/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
-
http://www.tuxera.com/support/
for common questions and known issues.
If you would find a new one in the latest release of
the software then please send an email describing it
in detail. You can contact the
development team on the ntfs-3g-devel@lists.sf.net
address.
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@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, 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)