1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
/*
* usnjrnl.h - Defines for NTFS kernel transaction log ($UsnJrnl) handling.
* Part of the Linux-NTFS project.
*
* Copyright (c) 2005 Anton Altaparmakov
*
* This program/include file is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program/include file is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (in the main directory of the Linux-NTFS
* distribution in the file COPYING); if not, write to the Free Software
* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _LINUX_NTFS_USNJRNL_H
#define _LINUX_NTFS_USNJRNL_H
#ifdef NTFS_RW
#include "types.h"
#include "endian.h"
#include "layout.h"
#include "volume.h"
/*
* Transaction log ($UsnJrnl) organization:
*
* The transaction log records whenever a file is modified in any way. So for
* example it will record that file "blah" was written to at a particular time
* but not what was written. If will record that a file was deleted or
* created, that a file was truncated, etc. See below for all the reason
* codes used.
*
* The transaction log is in the $Extend directory which is in the root
* directory of each volume. If it is not present it means transaction
* logging is disabled. If it is present it means transaction logging is
* either enabled or in the process of being disabled in which case we can
* ignore it as it will go away as soon as Windows gets its hands on it.
*
* To determine whether the transaction logging is enabled or in the process
* of being disabled, need to check the volume flags in the
* $VOLUME_INFORMATION attribute in the $Volume system file (which is present
* in the root directory and has a fixed mft record number, see layout.h).
* If the flag VOLUME_DELETE_USN_UNDERWAY is set it means the transaction log
* is in the process of being disabled and if this flag is clear it means the
* transaction log is enabled.
*
* The transaction log consists of two parts; the $DATA/$Max attribute as well
* as the $DATA/$J attribute. $Max is a header describing the transaction
* log whilst $J is the transaction log data itself as a sequence of variable
* sized USN_RECORDs (see below for all the structures).
*
* We do not care about transaction logging at this point in time but we still
* need to let windows know that the transaction log is out of date. To do
* this we need to stamp the transaction log. This involves setting the
* lowest_valid_usn field in the $DATA/$Max attribute to the usn to be used
* for the next added USN_RECORD to the $DATA/$J attribute as well as
* generating a new journal_id in $DATA/$Max.
*
* The journal_id is as of the current version (2.0) of the transaction log
* simply the 64-bit timestamp of when the journal was either created or last
* stamped.
*
* To determine the next usn there are two ways. The first is to parse
* $DATA/$J and to find the last USN_RECORD in it and to add its record_length
* to its usn (which is the byte offset in the $DATA/$J attribute). The
* second is simply to take the data size of the attribute. Since the usns
* are simply byte offsets into $DATA/$J, this is exactly the next usn. For
* obvious reasons we use the second method as it is much simpler and faster.
*
* As an aside, note that to actually disable the transaction log, one would
* need to set the VOLUME_DELETE_USN_UNDERWAY flag (see above), then go
* through all the mft records on the volume and set the usn field in their
* $STANDARD_INFORMATION attribute to zero. Once that is done, one would need
* to delete the transaction log file, i.e. \$Extent\$UsnJrnl, and finally,
* one would need to clear the VOLUME_DELETE_USN_UNDERWAY flag.
*
* Note that if a volume is unmounted whilst the transaction log is being
* disabled, the process will continue the next time the volume is mounted.
* This is why we can safely mount read-write when we see a transaction log
* in the process of being deleted.
*/
/* Some $UsnJrnl related constants. */
#define UsnJrnlMajorVer 2
#define UsnJrnlMinorVer 0
/*
* $DATA/$Max attribute. This is (always?) resident and has a fixed size of
* 32 bytes. It contains the header describing the transaction log.
*/
typedef struct {
/*Ofs*/
/* 0*/sle64 maximum_size; /* The maximum on-disk size of the $DATA/$J
attribute. */
/* 8*/sle64 allocation_delta; /* Number of bytes by which to increase the
size of the $DATA/$J attribute. */
/*0x10*/sle64 journal_id; /* Current id of the transaction log. */
/*0x18*/leUSN lowest_valid_usn; /* Lowest valid usn in $DATA/$J for the
current journal_id. */
/* sizeof() = 32 (0x20) bytes */
} __attribute__ ((__packed__)) USN_HEADER;
/*
* Reason flags (32-bit). Cumulative flags describing the change(s) to the
* file since it was last opened. I think the names speak for themselves but
* if you disagree check out the descriptions in the Linux NTFS project NTFS
* documentation: http://www.linux-ntfs.org/
*/
enum {
USN_REASON_DATA_OVERWRITE = cpu_to_le32(0x00000001),
USN_REASON_DATA_EXTEND = cpu_to_le32(0x00000002),
USN_REASON_DATA_TRUNCATION = cpu_to_le32(0x00000004),
USN_REASON_NAMED_DATA_OVERWRITE = cpu_to_le32(0x00000010),
USN_REASON_NAMED_DATA_EXTEND = cpu_to_le32(0x00000020),
USN_REASON_NAMED_DATA_TRUNCATION= cpu_to_le32(0x00000040),
USN_REASON_FILE_CREATE = cpu_to_le32(0x00000100),
USN_REASON_FILE_DELETE = cpu_to_le32(0x00000200),
USN_REASON_EA_CHANGE = cpu_to_le32(0x00000400),
USN_REASON_SECURITY_CHANGE = cpu_to_le32(0x00000800),
USN_REASON_RENAME_OLD_NAME = cpu_to_le32(0x00001000),
USN_REASON_RENAME_NEW_NAME = cpu_to_le32(0x00002000),
USN_REASON_INDEXABLE_CHANGE = cpu_to_le32(0x00004000),
USN_REASON_BASIC_INFO_CHANGE = cpu_to_le32(0x00008000),
USN_REASON_HARD_LINK_CHANGE = cpu_to_le32(0x00010000),
USN_REASON_COMPRESSION_CHANGE = cpu_to_le32(0x00020000),
USN_REASON_ENCRYPTION_CHANGE = cpu_to_le32(0x00040000),
USN_REASON_OBJECT_ID_CHANGE = cpu_to_le32(0x00080000),
USN_REASON_REPARSE_POINT_CHANGE = cpu_to_le32(0x00100000),
USN_REASON_STREAM_CHANGE = cpu_to_le32(0x00200000),
USN_REASON_CLOSE = cpu_to_le32(0x80000000),
};
typedef le32 USN_REASON_FLAGS;
/*
* Source info flags (32-bit). Information about the source of the change(s)
* to the file. For detailed descriptions of what these mean, see the Linux
* NTFS project NTFS documentation:
* http://www.linux-ntfs.org/
*/
enum {
USN_SOURCE_DATA_MANAGEMENT = cpu_to_le32(0x00000001),
USN_SOURCE_AUXILIARY_DATA = cpu_to_le32(0x00000002),
USN_SOURCE_REPLICATION_MANAGEMENT = cpu_to_le32(0x00000004),
};
typedef le32 USN_SOURCE_INFO_FLAGS;
/*
* $DATA/$J attribute. This is always non-resident, is marked as sparse, and
* is of variabled size. It consists of a sequence of variable size
* USN_RECORDS. The minimum allocated_size is allocation_delta as
* specified in $DATA/$Max. When the maximum_size specified in $DATA/$Max is
* exceeded by more than allocation_delta bytes, allocation_delta bytes are
* allocated and appended to the $DATA/$J attribute and an equal number of
* bytes at the beginning of the attribute are freed and made sparse. Note the
* making sparse only happens at volume checkpoints and hence the actual
* $DATA/$J size can exceed maximum_size + allocation_delta temporarily.
*/
typedef struct {
/*Ofs*/
/* 0*/le32 length; /* Byte size of this record (8-byte
aligned). */
/* 4*/le16 major_ver; /* Major version of the transaction log used
for this record. */
/* 6*/le16 minor_ver; /* Minor version of the transaction log used
for this record. */
/* 8*/leMFT_REF mft_reference;/* The mft reference of the file (or
directory) described by this record. */
/*0x10*/leMFT_REF parent_directory;/* The mft reference of the parent
directory of the file described by this
record. */
/*0x18*/leUSN usn; /* The usn of this record. Equals the offset
within the $DATA/$J attribute. */
/*0x20*/sle64 time; /* Time when this record was created. */
/*0x28*/USN_REASON_FLAGS reason;/* Reason flags (see above). */
/*0x2c*/USN_SOURCE_INFO_FLAGS source_info;/* Source info flags (see above). */
/*0x30*/le32 security_id; /* File security_id copied from
$STANDARD_INFORMATION. */
/*0x34*/FILE_ATTR_FLAGS file_attributes; /* File attributes copied from
$STANDARD_INFORMATION or $FILE_NAME (not
sure which). */
/*0x38*/le16 file_name_size; /* Size of the file name in bytes. */
/*0x3a*/le16 file_name_offset; /* Offset to the file name in bytes from the
start of this record. */
/*0x3c*/ntfschar file_name[0]; /* Use when creating only. When reading use
file_name_offset to determine the location
of the name. */
/* sizeof() = 60 (0x3c) bytes */
} __attribute__ ((__packed__)) USN_RECORD;
extern bool ntfs_stamp_usnjrnl(ntfs_volume *vol);
#endif /* NTFS_RW */
#endif /* _LINUX_NTFS_USNJRNL_H */
|
