1NTFS Overview
2=============
3
4Legato Systems, Inc. (http://www.legato.com) have sponsored Anton Altaparmakov
5to develop NTFS on Linux since June 2001.
6
7To mount an NTFS volume, use the filesystem type 'ntfs'. The driver
8currently works only in read-only mode, with no fault-tolerance supported.
9
10If you enable the dangerous(!) write support, make sure you can recover
11from a complete loss of data. Also, download the Linux-NTFS project
12distribution from Sourceforge at http://sourceforge.net/projects/linux-ntfs/
13and always run the included ntfsfix utility after performing a write to an
14NTFS partition from Linux to fix some of the damage done by the Linux NTFS
15driver and to schedule an automatic chkdsk when Windows reboots. You should
16run ntfsfix _after_ unmounting the partition in Linux but _before_ rebooting
17into Windows. During the next reboot into Windows, chkdsk will be run
18automatically fixing the remaining damage. If no errors are found it is a
19good indication that the driver + ntfsfix together worked to full
20satisfaction. (-;
21
22Please note that the experimental write support is limited to Windows NT4 and
23earlier versions at the moment.
24
25If you think you have discovered a bug please have look at the "Known bugs"
26section below to see whether it isn't known already.
27
28For ftdisk support, limited success was reported with volume sets on top of
29the md driver, although mirror and stripe sets should work as well - if the
30md driver can be talked into using the same layout as Windows NT. However,
31using the md driver will fail if any of your NTFS partitions have an odd
32number of sectors.
33
34Supported mount options
35=======================
36
37iocharset=name		Character set to use when returning file names.
38			Unlike VFAT, NTFS suppresses names that contain
39			unconvertible characters. Note that most character
40			sets contain insufficient characters to represent all
41			possible Unicode characters that can exist on NTFS. To
42			be sure you are not missing any files, you are advised
43			to use the iocharset=utf8 which should be capable of
44			representing all Unicode characters.
45
46utf8=<bool>		Use UTF-8 for converting file names. - It is preferable
47			to use iocharset=utf8 instead, but if the utf8 NLS is
48			not available, you can use this utf8 option, which
49			enables the driver's builtin utf8 conversion functions.
50
51uid=
52gid=
53umask=			These options work as documented in mount(8).
54			By default, the files are owned by root and
55			not readable by anyone else.
56
57posix=<bool>		If enabled, the file system distinguishes between
58			upper and lower case. The 8.3 alias names are presented
59			as hard links instead of being suppressed.
60
61show_sys_files=<bool>	If enabled, show all system files as normal files. Note
62			that $MFT does not appear unless specifically
63			requested. For example in bash, use: "ls -l \$MFT".
64			Be careful not to write anything to them or you could
65			crash the kernel and/or corrupt your file system!
66
67mft_zone_multiplier=	Set the MFT zone multiplier for the volume (this
68			setting is not persistent across mounts and can be
69			changed from mount to mount but cannot be changed on
70			remount). Values of 1 to 4 are allowed, 1 being the
71			default. The MFT zone multiplier determines how much
72			space is reserved for the MFT on the volume. If all
73			other space is used up, then the MFT zone will be
74			shrunk dynamically, so this has no impact on the
75			amount of free space. However, it can have an impact
76			on performance by affecting fragmentation of the MFT.
77			In general use the default. If you have a lot of small
78			files then use a higher value. The values have the
79			following meaning:
80			      Value	     MFT zone size (% of volume size)
81				1		12.5%
82				2		25%
83				3		37.5%
84				4		50%
85
86Known bugs and (mis-)features
87=============================
88
89- Do not use the driver for writing as it corrupts the file system. If you do
90  use it, get the Linux-NTFS tools and use the ntfsfix utility after
91  dismounting a partition you wrote to.
92
93- Writing of extension records is not supported properly.
94
95Please send bug reports/comments/feed back/abuse to the Linux-NTFS development
96list at sourceforge: linux-ntfs-dev@lists.sourceforge.net
97
98ChangeLog
99=========
100
101NTFS 1.1.21:
102	- Fixed bug with reading $MFT where we try to read higher mft records
103	  before having read the $DATA attribute of $MFT. (Note this is only a
104	  partial solution which will only work in the case that the attribute
105	  list is resident or non-resident but $DATA is in the first 1024
106	  bytes. But this should be enough in the majority of cases. I am not
107	  going to bother fixing the general case until someone finds this to
108	  be a problem for them, which I doubt very much will ever happen...)
109	- Fixed bogus BUG() call in readdir().
110
111NTFS 1.1.20:
112	- Fixed two bugs in ntfs_readwrite_attr(). Thanks to Jan Kara for
113	  spotting the out of bounds one.
114	- Check return value of set_blocksize() in ntfs_read_super() and make
115	  use of get_hardsect_size() to determine the minimum block size.
116	- Fix return values of ntfs_vcn_to_lcn(). This should stop
117	  peoples start of partition being overwritten at random.
118
119NTFS 1.1.19:
120	- Fixed ntfs_getdir_unsorted(), ntfs_readdir() and ntfs_printcb() to
121	  cope with arbitrary cluster sizes. Very important for Win2k+. Also,
122	  make them detect directories which are too large and truncate the
123	  enumeration pretending end of directory was reached. Detect more
124	  error conditions and overflows. All this fixes the problem where the
125	  driver could end up in an infinite loop under certain circumstances.
126	- Fixed potential memory leaks in Unicode conversion functions and
127	  setup correct NULL return values.
128
129NTFS 1.1.18:
130
131	- Enhanced & bug fixed cluster deallocation (race fixes, etc.)
132	- Complete rewrite of cluster allocation, now race free.
133	- Fixed several bugs in the attribute modification codepaths.
134	- Hopefully fixed bug where the first sectors of some people's
135	  partitions would be overwritten by the mft. And in general fixed up
136	  mft extension code a bit (still incomplete though).
137	- Introduce splice_runlist() to allow generic splicing of two run
138	  lists into one.
139	- MFT zone is now implemented. [Stage 2 of 3; only lack dynamic
140	  growing of mft zone but that is AFAIK not even done by Windows, and
141	  the overhead would be so large that it is probably not worth doing
142	  at all, so Stage 3 might never happen...]
143	- Complete rewrite of $MFT extension and ntfs inode allocation code.
144	- Made the NTFS driver initialization string show the compile options
145	  used (i.e. whether read-only or read-write, whether a module, and
146	  whether with debug support).
147	- Modify ntfs_fill_mft_header() to set all fields and to accept more
148	  arguments.
149	- Get rid of superfluous add_mft_header().
150	- Get rid of some unused code.
151	- Fixed several bugs in and generally cleaned up ntfs_readdir,
152	  ntfs_getdir_unsorted(), and ntfs_printcb. Now they spew out huge
153	  amounts of debug output if debugging is enabled. This will be
154	  removed once I know that this works for everyone.
155	- ntfs_readdir now shows hidden files. The only files that are now
156	  hidden are the first 16 inodes (i.e. the hard coded system files),
157	  which is consistent with Windows NT4. Using the show_sys_files mount
158	  option, these files are then shown, too.
159	- Fixed the displaying of the "." and ".." directories. We still cannot
160	  cope with more than 65536 files in a directory index block which is
161	  not a problem and we now cannot cope with more than 32766 directory
162	  index blocks which should not be a problem unless you have a
163	  directory with an insanely large number of files in it. The exact
164	  number depends on the length of the file names of the directory
165	  entries and on the size of the dircetory index blocks.
166	- Fixed all problems with the last file in a directory (e.g. the last
167	  file should no longer disappear and tab completion should work). If
168	  there are still disappearing files or any other problems with the
169	  last file in a directory, please report them! Thanks.
170	- Rewrote ntfs_extend_attr() to use the new cluster allocator and the
171	  freshly introduced splice_runlists() function. This simplified
172	  ntfs_extend_attr() a lot which in turn seems to have removed one or
173	  more bugs from it.
174	- Probably other things I have forgotten... (-;
175	- Removed dollar signs from the names in the system file enumeration.
176	  Apparently gcc doesn't support dollar signs on PPC architecture.
177	  (Andrzej Krzysztofowicz)
178
179NTFS 1.1.17:
180
181	- Fixed system file handling. No longer need to use show_sys_files
182	  option for driver to work fine. System files are now always treated
183	  the same, but without the option, they are made invisible to
184	  directory listings. As a result system files can once again be opened
185	  even without the show_sys_files option. This is important for the
186	  statfs system call to work properly, for example.
187	- Implemented MFT zone including mount parameter to tune it (just like
188	  in Windows via the registry, only we make it per mount rather than
189	  global for the whole driver, so we are better but we have no way of
190	  storing the value as we don't have a registry so either specify on
191	  each mount or put it in /etc/fstab). [Stage 1 of 3, mount parameter
192	  handling.]
193	- Fixed fixup functions to handle corruption cases and to return error
194	  codes to the caller.
195	- Made fixup functions apply hotfixes where sensible. [Stage 1 of 2+,
196	  in memory only.]
197	- Fixed ommission of "NTFS: " string in ntfs_error() output.
198	- Fixed stupid if statement bug in unistr.c. Thanks to Yann E. Morin
199	  for spotting it.
200	- Get rid of all uses of max and min macros. This actually allowed for
201	  optimizing the code in several places so it was a Good Thing(TM).
202	- Make ntfs use generic_file_open to enforce the O_LARGEFILE flag.
203	- Detect encrypted files and refuse to access them (return EACCES
204	  error code to user space).
205	- Fix handling of encrypted & compressed files so that an encrypted
206	  file no longer is considered to be compressed (this was causing
207	  kernel segmentation faults).
208
209NTFS 1.1.16:
210
211	- Removed non-functional uni_xlate mount options.
212	- Clarified the semantics of the utf8 and iocharset mount options.
213	- Threw out the non-functional mount options for using hard coded
214	  character set conversion. Only kept utf8 one.
215	- Fixed handling of mount options and proper handling of faulty mount
216	  options on remount.
217	- Cleaned up character conversion which basically became simplified a
218	  lot due to the removal of the above mentioned mount options.
219	- Made character conversion to be always consistent. Previously we
220	  could output to the VFS file names which we would then not accept
221	  back from the VFS so in effect we were generating ghost entries in
222	  the directory listings which could not be accessed by any means.
223	- Simplified time conversion functions drastically without sacrificing
224	  accuracy. (-8
225	- Fixed a use of a pointer before the check for the pointer being
226	  NULL, reported by the Stanford checker.
227	- Fixed several missing error checks, reported by the Stanford
228	  checker and fixed by Rasmus Andersen.
229
230NTFS 1.1.15 (changes since kernel 2.4.4's NTFS driver):
231
232	- New mount option show_sys_files=<bool> to show all system files as
233	  normal files.
234	- Support for files and in general any attributes up to the full 2TiB
235	  size supported by the NTFS filesystem. Note we only support up to
236	  32-bits worth of inodes/clusters at this point.
237	- Support for more than 128kiB sized runlists (using vmalloc_32()
238	  instead of kmalloc()).
239	- Fixed races in allocation of clusters and mft records.
240	- Fixed major bugs in attribute handling / searching / collation.
241	- Fixed major bugs in compressing a run list into a mapping pairs array.
242	- Fixed major bugs in inode allocation. Especially file create and
243	  mkdir.
244	- Fixed memory leaks.
245	- Fixed major bug in inode layout assignment of sequence numbers.
246	- Lots of other bug fixes I can't think of right now...
247	- Fixed NULL bug found by the Stanford checker in ntfs_dupuni2map().
248	- Convert large stack variable to dynamically allocated one in
249	  ntfs_get_free_cluster_count() (found by Stanford checker).
250
251Kernel 2.4.4:
252
253	- Started ChangeLog.
254
255