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1 | /* | ||
2 | * usnjrnl.h - Defines for NTFS kernel transaction log ($UsnJrnl) handling. | ||
3 | * Part of the Linux-NTFS project. | ||
4 | * | ||
5 | * Copyright (c) 2005 Anton Altaparmakov | ||
6 | * | ||
7 | * This program/include file is free software; you can redistribute it and/or | ||
8 | * modify it under the terms of the GNU General Public License as published | ||
9 | * by the Free Software Foundation; either version 2 of the License, or | ||
10 | * (at your option) any later version. | ||
11 | * | ||
12 | * This program/include file is distributed in the hope that it will be | ||
13 | * useful, but WITHOUT ANY WARRANTY; without even the implied warranty | ||
14 | * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
15 | * GNU General Public License for more details. | ||
16 | * | ||
17 | * You should have received a copy of the GNU General Public License | ||
18 | * along with this program (in the main directory of the Linux-NTFS | ||
19 | * distribution in the file COPYING); if not, write to the Free Software | ||
20 | * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | ||
21 | */ | ||
22 | |||
23 | #ifndef _LINUX_NTFS_USNJRNL_H | ||
24 | #define _LINUX_NTFS_USNJRNL_H | ||
25 | |||
26 | #ifdef NTFS_RW | ||
27 | |||
28 | #include "types.h" | ||
29 | #include "endian.h" | ||
30 | #include "layout.h" | ||
31 | #include "volume.h" | ||
32 | |||
33 | /* | ||
34 | * Transaction log ($UsnJrnl) organization: | ||
35 | * | ||
36 | * The transaction log records whenever a file is modified in any way. So for | ||
37 | * example it will record that file "blah" was written to at a particular time | ||
38 | * but not what was written. If will record that a file was deleted or | ||
39 | * created, that a file was truncated, etc. See below for all the reason | ||
40 | * codes used. | ||
41 | * | ||
42 | * The transaction log is in the $Extend directory which is in the root | ||
43 | * directory of each volume. If it is not present it means transaction | ||
44 | * logging is disabled. If it is present it means transaction logging is | ||
45 | * either enabled or in the process of being disabled in which case we can | ||
46 | * ignore it as it will go away as soon as Windows gets its hands on it. | ||
47 | * | ||
48 | * To determine whether the transaction logging is enabled or in the process | ||
49 | * of being disabled, need to check the volume flags in the | ||
50 | * $VOLUME_INFORMATION attribute in the $Volume system file (which is present | ||
51 | * in the root directory and has a fixed mft record number, see layout.h). | ||
52 | * If the flag VOLUME_DELETE_USN_UNDERWAY is set it means the transaction log | ||
53 | * is in the process of being disabled and if this flag is clear it means the | ||
54 | * transaction log is enabled. | ||
55 | * | ||
56 | * The transaction log consists of two parts; the $DATA/$Max attribute as well | ||
57 | * as the $DATA/$J attribute. $Max is a header describing the transaction | ||
58 | * log whilst $J is the transaction log data itself as a sequence of variable | ||
59 | * sized USN_RECORDs (see below for all the structures). | ||
60 | * | ||
61 | * We do not care about transaction logging at this point in time but we still | ||
62 | * need to let windows know that the transaction log is out of date. To do | ||
63 | * this we need to stamp the transaction log. This involves setting the | ||
64 | * lowest_valid_usn field in the $DATA/$Max attribute to the usn to be used | ||
65 | * for the next added USN_RECORD to the $DATA/$J attribute as well as | ||
66 | * generating a new journal_id in $DATA/$Max. | ||
67 | * | ||
68 | * The journal_id is as of the current version (2.0) of the transaction log | ||
69 | * simply the 64-bit timestamp of when the journal was either created or last | ||
70 | * stamped. | ||
71 | * | ||
72 | * To determine the next usn there are two ways. The first is to parse | ||
73 | * $DATA/$J and to find the last USN_RECORD in it and to add its record_length | ||
74 | * to its usn (which is the byte offset in the $DATA/$J attribute). The | ||
75 | * second is simply to take the data size of the attribute. Since the usns | ||
76 | * are simply byte offsets into $DATA/$J, this is exactly the next usn. For | ||
77 | * obvious reasons we use the second method as it is much simpler and faster. | ||
78 | * | ||
79 | * As an aside, note that to actually disable the transaction log, one would | ||
80 | * need to set the VOLUME_DELETE_USN_UNDERWAY flag (see above), then go | ||
81 | * through all the mft records on the volume and set the usn field in their | ||
82 | * $STANDARD_INFORMATION attribute to zero. Once that is done, one would need | ||
83 | * to delete the transaction log file, i.e. \$Extent\$UsnJrnl, and finally, | ||
84 | * one would need to clear the VOLUME_DELETE_USN_UNDERWAY flag. | ||
85 | * | ||
86 | * Note that if a volume is unmounted whilst the transaction log is being | ||
87 | * disabled, the process will continue the next time the volume is mounted. | ||
88 | * This is why we can safely mount read-write when we see a transaction log | ||
89 | * in the process of being deleted. | ||
90 | */ | ||
91 | |||
92 | /* Some $UsnJrnl related constants. */ | ||
93 | #define UsnJrnlMajorVer 2 | ||
94 | #define UsnJrnlMinorVer 0 | ||
95 | |||
96 | /* | ||
97 | * $DATA/$Max attribute. This is (always?) resident and has a fixed size of | ||
98 | * 32 bytes. It contains the header describing the transaction log. | ||
99 | */ | ||
100 | typedef struct { | ||
101 | /*Ofs*/ | ||
102 | /* 0*/sle64 maximum_size; /* The maximum on-disk size of the $DATA/$J | ||
103 | attribute. */ | ||
104 | /* 8*/sle64 allocation_delta; /* Number of bytes by which to increase the | ||
105 | size of the $DATA/$J attribute. */ | ||
106 | /*0x10*/sle64 journal_id; /* Current id of the transaction log. */ | ||
107 | /*0x18*/leUSN lowest_valid_usn; /* Lowest valid usn in $DATA/$J for the | ||
108 | current journal_id. */ | ||
109 | /* sizeof() = 32 (0x20) bytes */ | ||
110 | } __attribute__ ((__packed__)) USN_HEADER; | ||
111 | |||
112 | /* | ||
113 | * Reason flags (32-bit). Cumulative flags describing the change(s) to the | ||
114 | * file since it was last opened. I think the names speak for themselves but | ||
115 | * if you disagree check out the descriptions in the Linux NTFS project NTFS | ||
116 | * documentation: http://linux-ntfs.sourceforge.net/ntfs/files/usnjrnl.html | ||
117 | */ | ||
118 | enum { | ||
119 | USN_REASON_DATA_OVERWRITE = const_cpu_to_le32(0x00000001), | ||
120 | USN_REASON_DATA_EXTEND = const_cpu_to_le32(0x00000002), | ||
121 | USN_REASON_DATA_TRUNCATION = const_cpu_to_le32(0x00000004), | ||
122 | USN_REASON_NAMED_DATA_OVERWRITE = const_cpu_to_le32(0x00000010), | ||
123 | USN_REASON_NAMED_DATA_EXTEND = const_cpu_to_le32(0x00000020), | ||
124 | USN_REASON_NAMED_DATA_TRUNCATION= const_cpu_to_le32(0x00000040), | ||
125 | USN_REASON_FILE_CREATE = const_cpu_to_le32(0x00000100), | ||
126 | USN_REASON_FILE_DELETE = const_cpu_to_le32(0x00000200), | ||
127 | USN_REASON_EA_CHANGE = const_cpu_to_le32(0x00000400), | ||
128 | USN_REASON_SECURITY_CHANGE = const_cpu_to_le32(0x00000800), | ||
129 | USN_REASON_RENAME_OLD_NAME = const_cpu_to_le32(0x00001000), | ||
130 | USN_REASON_RENAME_NEW_NAME = const_cpu_to_le32(0x00002000), | ||
131 | USN_REASON_INDEXABLE_CHANGE = const_cpu_to_le32(0x00004000), | ||
132 | USN_REASON_BASIC_INFO_CHANGE = const_cpu_to_le32(0x00008000), | ||
133 | USN_REASON_HARD_LINK_CHANGE = const_cpu_to_le32(0x00010000), | ||
134 | USN_REASON_COMPRESSION_CHANGE = const_cpu_to_le32(0x00020000), | ||
135 | USN_REASON_ENCRYPTION_CHANGE = const_cpu_to_le32(0x00040000), | ||
136 | USN_REASON_OBJECT_ID_CHANGE = const_cpu_to_le32(0x00080000), | ||
137 | USN_REASON_REPARSE_POINT_CHANGE = const_cpu_to_le32(0x00100000), | ||
138 | USN_REASON_STREAM_CHANGE = const_cpu_to_le32(0x00200000), | ||
139 | USN_REASON_CLOSE = const_cpu_to_le32(0x80000000), | ||
140 | }; | ||
141 | |||
142 | typedef le32 USN_REASON_FLAGS; | ||
143 | |||
144 | /* | ||
145 | * Source info flags (32-bit). Information about the source of the change(s) | ||
146 | * to the file. For detailed descriptions of what these mean, see the Linux | ||
147 | * NTFS project NTFS documentation: | ||
148 | * http://linux-ntfs.sourceforge.net/ntfs/files/usnjrnl.html | ||
149 | */ | ||
150 | enum { | ||
151 | USN_SOURCE_DATA_MANAGEMENT = const_cpu_to_le32(0x00000001), | ||
152 | USN_SOURCE_AUXILIARY_DATA = const_cpu_to_le32(0x00000002), | ||
153 | USN_SOURCE_REPLICATION_MANAGEMENT = const_cpu_to_le32(0x00000004), | ||
154 | }; | ||
155 | |||
156 | typedef le32 USN_SOURCE_INFO_FLAGS; | ||
157 | |||
158 | /* | ||
159 | * $DATA/$J attribute. This is always non-resident, is marked as sparse, and | ||
160 | * is of variabled size. It consists of a sequence of variable size | ||
161 | * USN_RECORDS. The minimum allocated_size is allocation_delta as | ||
162 | * specified in $DATA/$Max. When the maximum_size specified in $DATA/$Max is | ||
163 | * exceeded by more than allocation_delta bytes, allocation_delta bytes are | ||
164 | * allocated and appended to the $DATA/$J attribute and an equal number of | ||
165 | * bytes at the beginning of the attribute are freed and made sparse. Note the | ||
166 | * making sparse only happens at volume checkpoints and hence the actual | ||
167 | * $DATA/$J size can exceed maximum_size + allocation_delta temporarily. | ||
168 | */ | ||
169 | typedef struct { | ||
170 | /*Ofs*/ | ||
171 | /* 0*/le32 length; /* Byte size of this record (8-byte | ||
172 | aligned). */ | ||
173 | /* 4*/le16 major_ver; /* Major version of the transaction log used | ||
174 | for this record. */ | ||
175 | /* 6*/le16 minor_ver; /* Minor version of the transaction log used | ||
176 | for this record. */ | ||
177 | /* 8*/leMFT_REF mft_reference;/* The mft reference of the file (or | ||
178 | directory) described by this record. */ | ||
179 | /*0x10*/leMFT_REF parent_directory;/* The mft reference of the parent | ||
180 | directory of the file described by this | ||
181 | record. */ | ||
182 | /*0x18*/leUSN usn; /* The usn of this record. Equals the offset | ||
183 | within the $DATA/$J attribute. */ | ||
184 | /*0x20*/sle64 time; /* Time when this record was created. */ | ||
185 | /*0x28*/USN_REASON_FLAGS reason;/* Reason flags (see above). */ | ||
186 | /*0x2c*/USN_SOURCE_INFO_FLAGS source_info;/* Source info flags (see above). */ | ||
187 | /*0x30*/le32 security_id; /* File security_id copied from | ||
188 | $STANDARD_INFORMATION. */ | ||
189 | /*0x34*/FILE_ATTR_FLAGS file_attributes; /* File attributes copied from | ||
190 | $STANDARD_INFORMATION or $FILE_NAME (not | ||
191 | sure which). */ | ||
192 | /*0x38*/le16 file_name_size; /* Size of the file name in bytes. */ | ||
193 | /*0x3a*/le16 file_name_offset; /* Offset to the file name in bytes from the | ||
194 | start of this record. */ | ||
195 | /*0x3c*/ntfschar file_name[0]; /* Use when creating only. When reading use | ||
196 | file_name_offset to determine the location | ||
197 | of the name. */ | ||
198 | /* sizeof() = 60 (0x3c) bytes */ | ||
199 | } __attribute__ ((__packed__)) USN_RECORD; | ||
200 | |||
201 | extern BOOL ntfs_stamp_usnjrnl(ntfs_volume *vol); | ||
202 | |||
203 | #endif /* NTFS_RW */ | ||
204 | |||
205 | #endif /* _LINUX_NTFS_USNJRNL_H */ | ||