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Commit d9704d82 authored by Anton Altaparmakov's avatar Anton Altaparmakov
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Merge cantab.net:/home/aia21/bklinux-2.5 

into cantab.net:/home/aia21/ntfs-2.6
parents 19323b83 c14fd3ec
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Documentation/filesystems/ntfs.txt
View file @ d9704d82
......@@ -6,8 +6,9 @@ Table of contents
=================
- Overview
- Supported mount options
- Web site
- Features
- Supported mount options
- Known bugs and (mis-)features
- Using Software RAID with NTFS
- Limitiations when using the MD driver
......@@ -17,13 +18,59 @@ Table of contents
Overview
========
To mount an NTFS 1.2/3.x (Windows NT4/2000/XP) volume, use the filesystem
type 'ntfs'. The driver currently works only in read-only mode, with no
fault-tolerance or journalling supported.
Linux-NTFS comes with a number of user-space programs known as ntfsprogs.
These include mkntfs, a full-featured ntfs file system format utility,
ntfsundelete used for recovering files that were unintentionally deleted
from an NTFS volume and ntfsresize which is used to resize an NTFS partition.
See the web site for more information.
To mount an NTFS 1.2/3.x (Windows NT4/2000/XP/2003) volume, use the file
system type 'ntfs'. The driver currently supports read-only mode (with no
fault-tolerance, encryption or journalling) and very limited, but safe, write
support.
For fault tolerance and raid support (i.e. volume and stripe sets), you can
use the kernel's Software RAID / MD driver. See section "Using Software RAID
with NTFS" for details.
Web site
========
There is plenty of additional information on the linux-ntfs web site
at http://linux-ntfs.sourceforge.net/
The web site has a lot of additional information, such as a comprehensive
FAQ, documentation on the NTFS on-disk format, informaiton on the Linux-NTFS
userspace utilities, etc.
For fault tolerance and raid support (i.e. volume and stripe sets), you can use
the kernel's Software RAID / MD driver. See section "Using Software RAID with
NTFS" for details.
Features
========
- This is a complete rewrite of the NTFS driver that used to be in the kernel.
This new driver implements NTFS read support and is functionally equivalent
to the old ntfs driver.
- The new driver has full support for sparse files on NTFS 3.x volumes which
the old driver isn't happy with.
- The new driver supports execution of binaries due to mmap() now being
supported.
- The new driver supports loopback mounting of files on NTFS which is used by
some Linux distributions to enable the user to run Linux from an NTFS
partition by creating a large file while in Windows and then loopback
mounting the file while in Linux and creating a Linux filesystem on it that
is used to install Linux on it.
- A comparison of the two drivers using:
time find . -type f -exec md5sum "{}" \;
run three times in sequence with each driver (after a reboot) on a 1.4GiB
NTFS partition, showed the new driver to be 20% faster in total time elapsed
(from 9:43 minutes on average down to 7:53). The time spent in user space
was unchanged but the time spent in the kernel was decreased by a factor of
2.5 (from 85 CPU seconds down to 33).
- The driver does not support short file names in general. For backwards
compatibility, we implement access to files using their short file names if
they exist. The driver will not create short file names however, and a rename
will discard any existing short file name.
Supported mount options
......@@ -33,31 +80,31 @@ In addition to the generic mount options described by the manual page for the
mount command (man 8 mount, also see man 5 fstab), the NTFS driver supports the
following mount options:
iocharset=name Deprecated option. Still supported but please use
nls=name in the future. See description for nls=name.
iocharset=name Deprecated option. Still supported but please use
nls=name in the future. See description for nls=name.
nls=name Character set to use when returning file names.
Unlike VFAT, NTFS suppresses names that contain
unconvertible characters. Note that most character
unconvertible characters. Note that most character
sets contain insufficient characters to represent all
possible Unicode characters that can exist on NTFS. To
be sure you are not missing any files, you are advised
to use nls=utf8 which is capable of representing all
Unicode characters.
possible Unicode characters that can exist on NTFS.
To be sure you are not missing any files, you are
advised to use nls=utf8 which is capable of
representing all Unicode characters.
utf8=<bool> Option no longer supported. Currently mapped to
utf8=<bool> Option no longer supported. Currently mapped to
nls=utf8 but please use nls=utf8 in the future and
make sure utf8 is compiled either as module or into
the kernel. See description for nls=name.
the kernel. See description for nls=name.
uid=
gid=
umask= Provide default owner, group, and access mode mask.
These options work as documented in mount(8). By
These options work as documented in mount(8). By
default, the files/directories are owned by root and
he/she has read and write permissions, as well as
browse permission for directories. No one else has any
access permissions. I.e. the mode on all files is by
browse permission for directories. No one else has any
access permissions. I.e. the mode on all files is by
default rw------- and for directories rwx------, a
consequence of the default fmask=0177 and dmask=0077.
Using a umask of zero will grant all permissions to
......@@ -74,7 +121,7 @@ sloppy=<BOOL> If sloppy is specified, ignore unknown mount options.
any unknown options are found.
show_sys_files=<BOOL> If show_sys_files is specified, show the system files
in directory listings. Otherwise the default behaviour
in directory listings. Otherwise the default behaviour
is to hide the system files.
Note that even when show_sys_files is specified, "$MFT"
will not be visible due to bugs/mis-features in glibc.
......@@ -85,15 +132,15 @@ show_sys_files=<BOOL> If show_sys_files is specified, show the system files
case_sensitive=<BOOL> If case_sensitive is specified, treat all file names as
case sensitive and create file names in the POSIX
namespace. Otherwise the default behaviour is to treat
namespace. Otherwise the default behaviour is to treat
file names as case insensitive and to create file names
in the WIN32/LONG name space. Note, the Linux NTFS
in the WIN32/LONG name space. Note, the Linux NTFS
driver will never create short file names and will
remove them on rename/delete of the corresponding long
file name.
Note that files remain accessible via their short file
name, if it exists. If case_sensitive, you will need to
provide the correct case of the short file name.
name, if it exists. If case_sensitive, you will need
to provide the correct case of the short file name.
errors=opt What to do when critical file system errors are found.
Following values can be used for "opt":
......@@ -102,27 +149,27 @@ errors=opt What to do when critical file system errors are found.
bad so it is no longer accessed, and then
continue.
recover: At present only supported is recovery of
the boot sector from the backup copy. If a
read-only mount, the recovery is done in
memory only and not written to disk.
the boot sector from the backup copy.
If read-only mount, the recovery is done
in memory only and not written to disk.
Note that the options are additive, i.e. specifying:
errors=continue,errors=recover
This means the driver will attempt to recover and if
that fails it will clean-up as much as possible and
means the driver will attempt to recover and if that
fails it will clean-up as much as possible and
continue.
mft_zone_multiplier= Set the MFT zone multiplier for the volume (this
setting is not persistent across mounts and can be
changed from mount to mount but cannot be changed on
remount). Values of 1 to 4 are allowed, 1 being the
default. The MFT zone multiplier determines how much
space is reserved for the MFT on the volume. If all
remount). Values of 1 to 4 are allowed, 1 being the
default. The MFT zone multiplier determines how much
space is reserved for the MFT on the volume. If all
other space is used up, then the MFT zone will be
shrunk dynamically, so this has no impact on the
amount of free space. However, it can have an impact
amount of free space. However, it can have an impact
on performance by affecting fragmentation of the MFT.
In general use the default. If you have a lot of small
files then use a higher value. The values have the
In general use the default. If you have a lot of small
files then use a higher value. The values have the
following meaning:
Value MFT zone size (% of volume size)
1 12.5%
......@@ -132,37 +179,14 @@ mft_zone_multiplier= Set the MFT zone multiplier for the volume (this
Note this option is irrelevant for read-only mounts.
Features
========
- This is a complete rewrite of the NTFS driver that used to be in the kernel.
This new driver implements NTFS read support and is functionally equivalent
to the old ntfs driver.
- The new driver has full support for sparse files on NTFS 3.x volumes which
the old driver isn't happy with.
- The new driver supports execution of binaries due to mmap() now being
supported.
- A comparison of the two drivers using:
time find . -type f -exec md5sum "{}" \;
run three times in sequence with each driver (after a reboot) on a 1.4GiB
NTFS partition, showed the new driver to be 20% faster in total time elapsed
(from 9:43 minutes on average down to 7:53). The time spent in user space
was unchanged but the time spent in the kernel was decreased by a factor of
2.5 (from 85 CPU seconds down to 33).
- The driver does not support short file names in general. For backwards
compatibility, we implement access to files using their short file names if
they exist. The driver will not create short file names however, and a rename
will discard any existing short file name.
Known bugs and (mis-)features
=============================
- The link count on each directory inode entry is set to 1, due to Linux not
supporting directory hard links. This may well confuse some user space
supporting directory hard links. This may well confuse some user space
applications, since the directory names will have the same inode numbers.
This also speeds up ntfs_read_inode() immensely. And we haven't found any
problems with this approach so far. If you find a problem with this, please
This also speeds up ntfs_read_inode() immensely. And we haven't found any
problems with this approach so far. If you find a problem with this, please
let us know.
......@@ -176,11 +200,11 @@ Using Software RAID with NTFS
For support of volume and stripe sets, use the kernel's Software RAID / MD
driver and set up your /etc/raidtab appropriately (see man 5 raidtab).
Linear volume sets, i.e. linear raid, as well as stripe sets, i.e. raid level 0,
have been tested and work fine (though see section "Limitiations when using the
MD driver with NTFS volumes" especially if you want to use linear raid). Even
though untested, there is no reason why mirrors, i.e. raid level 1, and stripes
with parity, i.e. raid level 5, should not work, too.
Linear volume sets, i.e. linear raid, as well as stripe sets, i.e. raid level
0, have been tested and work fine (though see section "Limitiations when using
the MD driver with NTFS volumes" especially if you want to use linear raid).
Even though untested, there is no reason why mirrors, i.e. raid level 1, and
stripes with parity, i.e. raid level 5, should not work, too.
You have to use the "persistent-superblock 0" option for each raid-disk in the
NTFS volume/stripe you are configuring in /etc/raidtab as the persistent
......@@ -207,15 +231,16 @@ For linear raid, just change the raid-level above to "raid-level linear", for
mirrors, change it to "raid-level 1", and for stripe sets with parity, change
it to "raid-level 5".
Note for stripe sets with parity you will also need to tell the MD driver which
parity algorithm to use by specifying the option "parity-algorithm which",
where you need to replace "which" with the name of the algorithm to use (see
man 5 raidtab for available algorithms) and you will have to try the different
available algorithms until you find one that works. Make sure you are working
read-only when playing with this as you may damage your data otherwise. If you
find which algorithm works please let us know (email the linux-ntfs developers
list linux-ntfs-dev@lists.sourceforge.net or drop in on IRC in channel #ntfs
on the irc.openprojects.net network) so we can update this documentation.
Note for stripe sets with parity you will also need to tell the MD driver
which parity algorithm to use by specifying the option "parity-algorithm
which", where you need to replace "which" with the name of the algorithm to
use (see man 5 raidtab for available algorithms) and you will have to try the
different available algorithms until you find one that works. Make sure you
are working read-only when playing with this as you may damage your data
otherwise. If you find which algorithm works please let us know (email the
linux-ntfs developers list linux-ntfs-dev@lists.sourceforge.net or drop in on
IRC in channel #ntfs on the irc.freenode.net network) so we can update this
documentation.
Once the raidtab is setup, run for example raid0run -a to start all devices or
raid0run /dev/md0 to start a particular md device, in this case /dev/md0.
......@@ -232,14 +257,14 @@ Limitiations when using the MD driver
=====================================
Using the md driver will not work properly if any of your NTFS partitions have
an odd number of sectors. This is especially important for linear raid as all
an odd number of sectors. This is especially important for linear raid as all
data after the first partition with an odd number of sectors will be offset by
one or more sectors so if you mount such a partition with write support you
will cause massive damage to the data on the volume which will only become
apparent when you try to use the volume again under Windows.
So when using linear raid, make sure that all your partitions have an even
number of sectors BEFORE attempting to use it. You have been warned!
number of sectors BEFORE attempting to use it. You have been warned!
ChangeLog
......
fs/Kconfig
View file @ d9704d82
......@@ -680,31 +680,45 @@ config UMSDOS_FS
module, so saying M could be dangerous. If unsure, say N.
config NTFS_FS
tristate "NTFS file system support (read only)"
tristate "NTFS file system support"
help
NTFS is the file system of Microsoft Windows NT/2000/XP. For more
information see <file:Documentation/filesystems/ntfs.txt>. Saying Y
here would allow you to read from NTFS partitions.
NTFS is the file system of Microsoft Windows NT, 2000, XP and 2003.
Saying Y or M here enables read support. There is partial, but
safe, write support available. For write support you must also
say Y to "NTFS write support" below.
There are also a number of user-space tools available, called
ntfsprogs. These include ntfsundelete and ntfsresize, that work
without NTFS support enabled in the kernel.
This is a rewrite from scratch of Linux NTFS support and replaced
the old NTFS code starting with Linux 2.5.11. A backport to
the Linux 2.4 kernel series is separately available as a patch
from the project web site.
For more information see <file:Documentation/filesystems/ntfs.txt>
and <http://linux-ntfs.sourceforge.net/>.
This file system is also available as a module ( = code which can be
inserted in and removed from the running kernel whenever you want).
The module will be called ntfs. If you want to compile it as a
The module will be called ntfs. If you want to compile it as a
module, say M here and read <file:Documentation/modules.txt>.
If you are not using Windows NT/2000/XP in addition to Linux on your
computer it is safe to say N.
If you are not using Windows NT, 2000, XP or 2003 in addition to
Linux on your computer it is safe to say N.
config NTFS_DEBUG
bool "NTFS debugging support"
depends on NTFS_FS
help
If you are experiencing any problems with the NTFS file system, say
Y here. This will result in additional consistency checks to be
Y here. This will result in additional consistency checks to be
performed by the driver as well as additional debugging messages to
be written to the system log. Note that debugging messages are
disabled by default. To enable them, supply the option debug_msgs=1
be written to the system log. Note that debugging messages are
disabled by default. To enable them, supply the option debug_msgs=1
at the kernel command line when booting the kernel or as an option
to insmod when loading the ntfs module. Once the driver is active,
to insmod when loading the ntfs module. Once the driver is active,
you can enable debugging messages by doing (as root):
echo 1 > /proc/sys/fs/ntfs-debug
Replacing the "1" with "0" would disable debug messages.
......@@ -717,16 +731,33 @@ config NTFS_DEBUG
debugging messages while the misbehaviour was occurring.
config NTFS_RW
bool "NTFS write support (DANGEROUS)"
depends on NTFS_FS && EXPERIMENTAL
bool "NTFS write support"
depends on NTFS_FS
help
This enables the experimental write support in the NTFS driver.
This enables the partial, but safe, write support in the NTFS driver.
The only supported operation is overwriting existing files, without
changing the file length. No file or directory creation, deletion or
renaming is possible. Note only non-resident files can be written to
so you may find that some very small files (<500 bytes or so) cannot
be written to.
While we cannot guarantee that it will not damage any data, we have
so far not received a single report where the driver would have
damaged someones data so we assume it is perfectly safe to use.
Note: While write support is safe in this version (a rewrite from
scratch of the NTFS support), it should be noted that the old NTFS
write support, included in Linux 2.5.10 and before (since 1997),
is not safe.
WARNING: Do not use this option unless you are actively developing
NTFS as it is currently guaranteed to be broken and you
may lose all your data!
This is currently useful with TopologiLinux. TopologiLinux is run
on top of any DOS/Microsoft Windows system without partitioning your
hard disk. Unlike other Linux distributions TopologiLinux does not
need its own partition. For more information see
<http://topologi-linux.sourceforge.net/>
It is strongly recommended and perfectly safe to say N here.
It is perfectly safe to say N here.
endmenu
......
fs/ntfs/layout.h
View file @ d9704d82
......@@ -42,8 +42,8 @@
#define const_cpu_to_le32(x) __constant_cpu_to_le32(x)
#define const_cpu_to_le64(x) __constant_cpu_to_le64(x)
/* The NTFS oem_id */
#define magicNTFS const_cpu_to_le64(0x202020205346544e) /* "NTFS " */
/* The NTFS oem_id "NTFS " */
#define magicNTFS const_cpu_to_le64(0x202020205346544eULL)
/*
* Location of bootsector on partition:
......
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