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0001 /* SPDX-License-Identifier: GPL-2.0-or-later */ 0002 /* 0003 * logfile.h - Defines for NTFS kernel journal ($LogFile) handling. Part of 0004 * the Linux-NTFS project. 0005 * 0006 * Copyright (c) 2000-2005 Anton Altaparmakov 0007 */ 0008 0009 #ifndef _LINUX_NTFS_LOGFILE_H 0010 #define _LINUX_NTFS_LOGFILE_H 0011 0012 #ifdef NTFS_RW 0013 0014 #include <linux/fs.h> 0015 0016 #include "types.h" 0017 #include "endian.h" 0018 #include "layout.h" 0019 0020 /* 0021 * Journal ($LogFile) organization: 0022 * 0023 * Two restart areas present in the first two pages (restart pages, one restart 0024 * area in each page). When the volume is dismounted they should be identical, 0025 * except for the update sequence array which usually has a different update 0026 * sequence number. 0027 * 0028 * These are followed by log records organized in pages headed by a log record 0029 * header going up to log file size. Not all pages contain log records when a 0030 * volume is first formatted, but as the volume ages, all records will be used. 0031 * When the log file fills up, the records at the beginning are purged (by 0032 * modifying the oldest_lsn to a higher value presumably) and writing begins 0033 * at the beginning of the file. Effectively, the log file is viewed as a 0034 * circular entity. 0035 * 0036 * NOTE: Windows NT, 2000, and XP all use log file version 1.1 but they accept 0037 * versions <= 1.x, including 0.-1. (Yes, that is a minus one in there!) We 0038 * probably only want to support 1.1 as this seems to be the current version 0039 * and we don't know how that differs from the older versions. The only 0040 * exception is if the journal is clean as marked by the two restart pages 0041 * then it doesn't matter whether we are on an earlier version. We can just 0042 * reinitialize the logfile and start again with version 1.1. 0043 */ 0044 0045 /* Some $LogFile related constants. */ 0046 #define MaxLogFileSize 0x100000000ULL 0047 #define DefaultLogPageSize 4096 0048 #define MinLogRecordPages 48 0049 0050 /* 0051 * Log file restart page header (begins the restart area). 0052 */ 0053 typedef struct { 0054 /*Ofs*/ 0055 /* 0 NTFS_RECORD; -- Unfolded here as gcc doesn't like unnamed structs. */ 0056 /* 0*/ NTFS_RECORD_TYPE magic; /* The magic is "RSTR". */ 0057 /* 4*/ le16 usa_ofs; /* See NTFS_RECORD definition in layout.h. 0058 When creating, set this to be immediately 0059 after this header structure (without any 0060 alignment). */ 0061 /* 6*/ le16 usa_count; /* See NTFS_RECORD definition in layout.h. */ 0062 0063 /* 8*/ leLSN chkdsk_lsn; /* The last log file sequence number found by 0064 chkdsk. Only used when the magic is changed 0065 to "CHKD". Otherwise this is zero. */ 0066 /* 16*/ le32 system_page_size; /* Byte size of system pages when the log file 0067 was created, has to be >= 512 and a power of 0068 2. Use this to calculate the required size 0069 of the usa (usa_count) and add it to usa_ofs. 0070 Then verify that the result is less than the 0071 value of the restart_area_offset. */ 0072 /* 20*/ le32 log_page_size; /* Byte size of log file pages, has to be >= 0073 512 and a power of 2. The default is 4096 0074 and is used when the system page size is 0075 between 4096 and 8192. Otherwise this is 0076 set to the system page size instead. */ 0077 /* 24*/ le16 restart_area_offset;/* Byte offset from the start of this header to 0078 the RESTART_AREA. Value has to be aligned 0079 to 8-byte boundary. When creating, set this 0080 to be after the usa. */ 0081 /* 26*/ sle16 minor_ver; /* Log file minor version. Only check if major 0082 version is 1. */ 0083 /* 28*/ sle16 major_ver; /* Log file major version. We only support 0084 version 1.1. */ 0085 /* sizeof() = 30 (0x1e) bytes */ 0086 } __attribute__ ((__packed__)) RESTART_PAGE_HEADER; 0087 0088 /* 0089 * Constant for the log client indices meaning that there are no client records 0090 * in this particular client array. Also inside the client records themselves, 0091 * this means that there are no client records preceding or following this one. 0092 */ 0093 #define LOGFILE_NO_CLIENT cpu_to_le16(0xffff) 0094 #define LOGFILE_NO_CLIENT_CPU 0xffff 0095 0096 /* 0097 * These are the so far known RESTART_AREA_* flags (16-bit) which contain 0098 * information about the log file in which they are present. 0099 */ 0100 enum { 0101 RESTART_VOLUME_IS_CLEAN = cpu_to_le16(0x0002), 0102 RESTART_SPACE_FILLER = cpu_to_le16(0xffff), /* gcc: Force enum bit width to 16. */ 0103 } __attribute__ ((__packed__)); 0104 0105 typedef le16 RESTART_AREA_FLAGS; 0106 0107 /* 0108 * Log file restart area record. The offset of this record is found by adding 0109 * the offset of the RESTART_PAGE_HEADER to the restart_area_offset value found 0110 * in it. See notes at restart_area_offset above. 0111 */ 0112 typedef struct { 0113 /*Ofs*/ 0114 /* 0*/ leLSN current_lsn; /* The current, i.e. last LSN inside the log 0115 when the restart area was last written. 0116 This happens often but what is the interval? 0117 Is it just fixed time or is it every time a 0118 check point is written or somethine else? 0119 On create set to 0. */ 0120 /* 8*/ le16 log_clients; /* Number of log client records in the array of 0121 log client records which follows this 0122 restart area. Must be 1. */ 0123 /* 10*/ le16 client_free_list; /* The index of the first free log client record 0124 in the array of log client records. 0125 LOGFILE_NO_CLIENT means that there are no 0126 free log client records in the array. 0127 If != LOGFILE_NO_CLIENT, check that 0128 log_clients > client_free_list. On Win2k 0129 and presumably earlier, on a clean volume 0130 this is != LOGFILE_NO_CLIENT, and it should 0131 be 0, i.e. the first (and only) client 0132 record is free and thus the logfile is 0133 closed and hence clean. A dirty volume 0134 would have left the logfile open and hence 0135 this would be LOGFILE_NO_CLIENT. On WinXP 0136 and presumably later, the logfile is always 0137 open, even on clean shutdown so this should 0138 always be LOGFILE_NO_CLIENT. */ 0139 /* 12*/ le16 client_in_use_list;/* The index of the first in-use log client 0140 record in the array of log client records. 0141 LOGFILE_NO_CLIENT means that there are no 0142 in-use log client records in the array. If 0143 != LOGFILE_NO_CLIENT check that log_clients 0144 > client_in_use_list. On Win2k and 0145 presumably earlier, on a clean volume this 0146 is LOGFILE_NO_CLIENT, i.e. there are no 0147 client records in use and thus the logfile 0148 is closed and hence clean. A dirty volume 0149 would have left the logfile open and hence 0150 this would be != LOGFILE_NO_CLIENT, and it 0151 should be 0, i.e. the first (and only) 0152 client record is in use. On WinXP and 0153 presumably later, the logfile is always 0154 open, even on clean shutdown so this should 0155 always be 0. */ 0156 /* 14*/ RESTART_AREA_FLAGS flags;/* Flags modifying LFS behaviour. On Win2k 0157 and presumably earlier this is always 0. On 0158 WinXP and presumably later, if the logfile 0159 was shutdown cleanly, the second bit, 0160 RESTART_VOLUME_IS_CLEAN, is set. This bit 0161 is cleared when the volume is mounted by 0162 WinXP and set when the volume is dismounted, 0163 thus if the logfile is dirty, this bit is 0164 clear. Thus we don't need to check the 0165 Windows version to determine if the logfile 0166 is clean. Instead if the logfile is closed, 0167 we know it must be clean. If it is open and 0168 this bit is set, we also know it must be 0169 clean. If on the other hand the logfile is 0170 open and this bit is clear, we can be almost 0171 certain that the logfile is dirty. */ 0172 /* 16*/ le32 seq_number_bits; /* How many bits to use for the sequence 0173 number. This is calculated as 67 - the 0174 number of bits required to store the logfile 0175 size in bytes and this can be used in with 0176 the specified file_size as a consistency 0177 check. */ 0178 /* 20*/ le16 restart_area_length;/* Length of the restart area including the 0179 client array. Following checks required if 0180 version matches. Otherwise, skip them. 0181 restart_area_offset + restart_area_length 0182 has to be <= system_page_size. Also, 0183 restart_area_length has to be >= 0184 client_array_offset + (log_clients * 0185 sizeof(log client record)). */ 0186 /* 22*/ le16 client_array_offset;/* Offset from the start of this record to 0187 the first log client record if versions are 0188 matched. When creating, set this to be 0189 after this restart area structure, aligned 0190 to 8-bytes boundary. If the versions do not 0191 match, this is ignored and the offset is 0192 assumed to be (sizeof(RESTART_AREA) + 7) & 0193 ~7, i.e. rounded up to first 8-byte 0194 boundary. Either way, client_array_offset 0195 has to be aligned to an 8-byte boundary. 0196 Also, restart_area_offset + 0197 client_array_offset has to be <= 510. 0198 Finally, client_array_offset + (log_clients 0199 * sizeof(log client record)) has to be <= 0200 system_page_size. On Win2k and presumably 0201 earlier, this is 0x30, i.e. immediately 0202 following this record. On WinXP and 0203 presumably later, this is 0x40, i.e. there 0204 are 16 extra bytes between this record and 0205 the client array. This probably means that 0206 the RESTART_AREA record is actually bigger 0207 in WinXP and later. */ 0208 /* 24*/ sle64 file_size; /* Usable byte size of the log file. If the 0209 restart_area_offset + the offset of the 0210 file_size are > 510 then corruption has 0211 occurred. This is the very first check when 0212 starting with the restart_area as if it 0213 fails it means that some of the above values 0214 will be corrupted by the multi sector 0215 transfer protection. The file_size has to 0216 be rounded down to be a multiple of the 0217 log_page_size in the RESTART_PAGE_HEADER and 0218 then it has to be at least big enough to 0219 store the two restart pages and 48 (0x30) 0220 log record pages. */ 0221 /* 32*/ le32 last_lsn_data_length;/* Length of data of last LSN, not including 0222 the log record header. On create set to 0223 0. */ 0224 /* 36*/ le16 log_record_header_length;/* Byte size of the log record header. 0225 If the version matches then check that the 0226 value of log_record_header_length is a 0227 multiple of 8, i.e. 0228 (log_record_header_length + 7) & ~7 == 0229 log_record_header_length. When creating set 0230 it to sizeof(LOG_RECORD_HEADER), aligned to 0231 8 bytes. */ 0232 /* 38*/ le16 log_page_data_offset;/* Offset to the start of data in a log record 0233 page. Must be a multiple of 8. On create 0234 set it to immediately after the update 0235 sequence array of the log record page. */ 0236 /* 40*/ le32 restart_log_open_count;/* A counter that gets incremented every 0237 time the logfile is restarted which happens 0238 at mount time when the logfile is opened. 0239 When creating set to a random value. Win2k 0240 sets it to the low 32 bits of the current 0241 system time in NTFS format (see time.h). */ 0242 /* 44*/ le32 reserved; /* Reserved/alignment to 8-byte boundary. */ 0243 /* sizeof() = 48 (0x30) bytes */ 0244 } __attribute__ ((__packed__)) RESTART_AREA; 0245 0246 /* 0247 * Log client record. The offset of this record is found by adding the offset 0248 * of the RESTART_AREA to the client_array_offset value found in it. 0249 */ 0250 typedef struct { 0251 /*Ofs*/ 0252 /* 0*/ leLSN oldest_lsn; /* Oldest LSN needed by this client. On create 0253 set to 0. */ 0254 /* 8*/ leLSN client_restart_lsn;/* LSN at which this client needs to restart 0255 the volume, i.e. the current position within 0256 the log file. At present, if clean this 0257 should = current_lsn in restart area but it 0258 probably also = current_lsn when dirty most 0259 of the time. At create set to 0. */ 0260 /* 16*/ le16 prev_client; /* The offset to the previous log client record 0261 in the array of log client records. 0262 LOGFILE_NO_CLIENT means there is no previous 0263 client record, i.e. this is the first one. 0264 This is always LOGFILE_NO_CLIENT. */ 0265 /* 18*/ le16 next_client; /* The offset to the next log client record in 0266 the array of log client records. 0267 LOGFILE_NO_CLIENT means there are no next 0268 client records, i.e. this is the last one. 0269 This is always LOGFILE_NO_CLIENT. */ 0270 /* 20*/ le16 seq_number; /* On Win2k and presumably earlier, this is set 0271 to zero every time the logfile is restarted 0272 and it is incremented when the logfile is 0273 closed at dismount time. Thus it is 0 when 0274 dirty and 1 when clean. On WinXP and 0275 presumably later, this is always 0. */ 0276 /* 22*/ u8 reserved[6]; /* Reserved/alignment. */ 0277 /* 28*/ le32 client_name_length;/* Length of client name in bytes. Should 0278 always be 8. */ 0279 /* 32*/ ntfschar client_name[64];/* Name of the client in Unicode. Should 0280 always be "NTFS" with the remaining bytes 0281 set to 0. */ 0282 /* sizeof() = 160 (0xa0) bytes */ 0283 } __attribute__ ((__packed__)) LOG_CLIENT_RECORD; 0284 0285 extern bool ntfs_check_logfile(struct inode *log_vi, 0286 RESTART_PAGE_HEADER **rp); 0287 0288 extern bool ntfs_is_logfile_clean(struct inode *log_vi, 0289 const RESTART_PAGE_HEADER *rp); 0290 0291 extern bool ntfs_empty_logfile(struct inode *log_vi); 0292 0293 #endif /* NTFS_RW */ 0294 0295 #endif /* _LINUX_NTFS_LOGFILE_H */
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