diff options
Diffstat (limited to 'fs/ntfs/logfile.h')
| -rw-r--r-- | fs/ntfs/logfile.h | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/fs/ntfs/logfile.h b/fs/ntfs/logfile.h new file mode 100644 index 000000000..aa2b6ac3f --- /dev/null +++ b/fs/ntfs/logfile.h @@ -0,0 +1,309 @@ +/* + * logfile.h - Defines for NTFS kernel journal ($LogFile) handling. Part of + * the Linux-NTFS project. + * + * Copyright (c) 2000-2005 Anton Altaparmakov + * + * This program/include file is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program/include file is distributed in the hope that it will be + * useful, but WITHOUT ANY WARRANTY; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program (in the main directory of the Linux-NTFS + * distribution in the file COPYING); if not, write to the Free Software + * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef _LINUX_NTFS_LOGFILE_H +#define _LINUX_NTFS_LOGFILE_H + +#ifdef NTFS_RW + +#include <linux/fs.h> + +#include "types.h" +#include "endian.h" +#include "layout.h" + +/* + * Journal ($LogFile) organization: + * + * Two restart areas present in the first two pages (restart pages, one restart + * area in each page). When the volume is dismounted they should be identical, + * except for the update sequence array which usually has a different update + * sequence number. + * + * These are followed by log records organized in pages headed by a log record + * header going up to log file size. Not all pages contain log records when a + * volume is first formatted, but as the volume ages, all records will be used. + * When the log file fills up, the records at the beginning are purged (by + * modifying the oldest_lsn to a higher value presumably) and writing begins + * at the beginning of the file. Effectively, the log file is viewed as a + * circular entity. + * + * NOTE: Windows NT, 2000, and XP all use log file version 1.1 but they accept + * versions <= 1.x, including 0.-1. (Yes, that is a minus one in there!) We + * probably only want to support 1.1 as this seems to be the current version + * and we don't know how that differs from the older versions. The only + * exception is if the journal is clean as marked by the two restart pages + * then it doesn't matter whether we are on an earlier version. We can just + * reinitialize the logfile and start again with version 1.1. + */ + +/* Some $LogFile related constants. */ +#define MaxLogFileSize 0x100000000ULL +#define DefaultLogPageSize 4096 +#define MinLogRecordPages 48 + +/* + * Log file restart page header (begins the restart area). + */ +typedef struct { +/*Ofs*/ +/* 0 NTFS_RECORD; -- Unfolded here as gcc doesn't like unnamed structs. */ +/* 0*/ NTFS_RECORD_TYPE magic; /* The magic is "RSTR". */ +/* 4*/ le16 usa_ofs; /* See NTFS_RECORD definition in layout.h. + When creating, set this to be immediately + after this header structure (without any + alignment). */ +/* 6*/ le16 usa_count; /* See NTFS_RECORD definition in layout.h. */ + +/* 8*/ leLSN chkdsk_lsn; /* The last log file sequence number found by + chkdsk. Only used when the magic is changed + to "CHKD". Otherwise this is zero. */ +/* 16*/ le32 system_page_size; /* Byte size of system pages when the log file + was created, has to be >= 512 and a power of + 2. Use this to calculate the required size + of the usa (usa_count) and add it to usa_ofs. + Then verify that the result is less than the + value of the restart_area_offset. */ +/* 20*/ le32 log_page_size; /* Byte size of log file pages, has to be >= + 512 and a power of 2. The default is 4096 + and is used when the system page size is + between 4096 and 8192. Otherwise this is + set to the system page size instead. */ +/* 24*/ le16 restart_area_offset;/* Byte offset from the start of this header to + the RESTART_AREA. Value has to be aligned + to 8-byte boundary. When creating, set this + to be after the usa. */ +/* 26*/ sle16 minor_ver; /* Log file minor version. Only check if major + version is 1. */ +/* 28*/ sle16 major_ver; /* Log file major version. We only support + version 1.1. */ +/* sizeof() = 30 (0x1e) bytes */ +} __attribute__ ((__packed__)) RESTART_PAGE_HEADER; + +/* + * Constant for the log client indices meaning that there are no client records + * in this particular client array. Also inside the client records themselves, + * this means that there are no client records preceding or following this one. + */ +#define LOGFILE_NO_CLIENT cpu_to_le16(0xffff) +#define LOGFILE_NO_CLIENT_CPU 0xffff + +/* + * These are the so far known RESTART_AREA_* flags (16-bit) which contain + * information about the log file in which they are present. + */ +enum { + RESTART_VOLUME_IS_CLEAN = cpu_to_le16(0x0002), + RESTART_SPACE_FILLER = cpu_to_le16(0xffff), /* gcc: Force enum bit width to 16. */ +} __attribute__ ((__packed__)); + +typedef le16 RESTART_AREA_FLAGS; + +/* + * Log file restart area record. The offset of this record is found by adding + * the offset of the RESTART_PAGE_HEADER to the restart_area_offset value found + * in it. See notes at restart_area_offset above. + */ +typedef struct { +/*Ofs*/ +/* 0*/ leLSN current_lsn; /* The current, i.e. last LSN inside the log + when the restart area was last written. + This happens often but what is the interval? + Is it just fixed time or is it every time a + check point is written or somethine else? + On create set to 0. */ +/* 8*/ le16 log_clients; /* Number of log client records in the array of + log client records which follows this + restart area. Must be 1. */ +/* 10*/ le16 client_free_list; /* The index of the first free log client record + in the array of log client records. + LOGFILE_NO_CLIENT means that there are no + free log client records in the array. + If != LOGFILE_NO_CLIENT, check that + log_clients > client_free_list. On Win2k + and presumably earlier, on a clean volume + this is != LOGFILE_NO_CLIENT, and it should + be 0, i.e. the first (and only) client + record is free and thus the logfile is + closed and hence clean. A dirty volume + would have left the logfile open and hence + this would be LOGFILE_NO_CLIENT. On WinXP + and presumably later, the logfile is always + open, even on clean shutdown so this should + always be LOGFILE_NO_CLIENT. */ +/* 12*/ le16 client_in_use_list;/* The index of the first in-use log client + record in the array of log client records. + LOGFILE_NO_CLIENT means that there are no + in-use log client records in the array. If + != LOGFILE_NO_CLIENT check that log_clients + > client_in_use_list. On Win2k and + presumably earlier, on a clean volume this + is LOGFILE_NO_CLIENT, i.e. there are no + client records in use and thus the logfile + is closed and hence clean. A dirty volume + would have left the logfile open and hence + this would be != LOGFILE_NO_CLIENT, and it + should be 0, i.e. the first (and only) + client record is in use. On WinXP and + presumably later, the logfile is always + open, even on clean shutdown so this should + always be 0. */ +/* 14*/ RESTART_AREA_FLAGS flags;/* Flags modifying LFS behaviour. On Win2k + and presumably earlier this is always 0. On + WinXP and presumably later, if the logfile + was shutdown cleanly, the second bit, + RESTART_VOLUME_IS_CLEAN, is set. This bit + is cleared when the volume is mounted by + WinXP and set when the volume is dismounted, + thus if the logfile is dirty, this bit is + clear. Thus we don't need to check the + Windows version to determine if the logfile + is clean. Instead if the logfile is closed, + we know it must be clean. If it is open and + this bit is set, we also know it must be + clean. If on the other hand the logfile is + open and this bit is clear, we can be almost + certain that the logfile is dirty. */ +/* 16*/ le32 seq_number_bits; /* How many bits to use for the sequence + number. This is calculated as 67 - the + number of bits required to store the logfile + size in bytes and this can be used in with + the specified file_size as a consistency + check. */ +/* 20*/ le16 restart_area_length;/* Length of the restart area including the + client array. Following checks required if + version matches. Otherwise, skip them. + restart_area_offset + restart_area_length + has to be <= system_page_size. Also, + restart_area_length has to be >= + client_array_offset + (log_clients * + sizeof(log client record)). */ +/* 22*/ le16 client_array_offset;/* Offset from the start of this record to + the first log client record if versions are + matched. When creating, set this to be + after this restart area structure, aligned + to 8-bytes boundary. If the versions do not + match, this is ignored and the offset is + assumed to be (sizeof(RESTART_AREA) + 7) & + ~7, i.e. rounded up to first 8-byte + boundary. Either way, client_array_offset + has to be aligned to an 8-byte boundary. + Also, restart_area_offset + + client_array_offset has to be <= 510. + Finally, client_array_offset + (log_clients + * sizeof(log client record)) has to be <= + system_page_size. On Win2k and presumably + earlier, this is 0x30, i.e. immediately + following this record. On WinXP and + presumably later, this is 0x40, i.e. there + are 16 extra bytes between this record and + the client array. This probably means that + the RESTART_AREA record is actually bigger + in WinXP and later. */ +/* 24*/ sle64 file_size; /* Usable byte size of the log file. If the + restart_area_offset + the offset of the + file_size are > 510 then corruption has + occurred. This is the very first check when + starting with the restart_area as if it + fails it means that some of the above values + will be corrupted by the multi sector + transfer protection. The file_size has to + be rounded down to be a multiple of the + log_page_size in the RESTART_PAGE_HEADER and + then it has to be at least big enough to + store the two restart pages and 48 (0x30) + log record pages. */ +/* 32*/ le32 last_lsn_data_length;/* Length of data of last LSN, not including + the log record header. On create set to + 0. */ +/* 36*/ le16 log_record_header_length;/* Byte size of the log record header. + If the version matches then check that the + value of log_record_header_length is a + multiple of 8, i.e. + (log_record_header_length + 7) & ~7 == + log_record_header_length. When creating set + it to sizeof(LOG_RECORD_HEADER), aligned to + 8 bytes. */ +/* 38*/ le16 log_page_data_offset;/* Offset to the start of data in a log record + page. Must be a multiple of 8. On create + set it to immediately after the update + sequence array of the log record page. */ +/* 40*/ le32 restart_log_open_count;/* A counter that gets incremented every + time the logfile is restarted which happens + at mount time when the logfile is opened. + When creating set to a random value. Win2k + sets it to the low 32 bits of the current + system time in NTFS format (see time.h). */ +/* 44*/ le32 reserved; /* Reserved/alignment to 8-byte boundary. */ +/* sizeof() = 48 (0x30) bytes */ +} __attribute__ ((__packed__)) RESTART_AREA; + +/* + * Log client record. The offset of this record is found by adding the offset + * of the RESTART_AREA to the client_array_offset value found in it. + */ +typedef struct { +/*Ofs*/ +/* 0*/ leLSN oldest_lsn; /* Oldest LSN needed by this client. On create + set to 0. */ +/* 8*/ leLSN client_restart_lsn;/* LSN at which this client needs to restart + the volume, i.e. the current position within + the log file. At present, if clean this + should = current_lsn in restart area but it + probably also = current_lsn when dirty most + of the time. At create set to 0. */ +/* 16*/ le16 prev_client; /* The offset to the previous log client record + in the array of log client records. + LOGFILE_NO_CLIENT means there is no previous + client record, i.e. this is the first one. + This is always LOGFILE_NO_CLIENT. */ +/* 18*/ le16 next_client; /* The offset to the next log client record in + the array of log client records. + LOGFILE_NO_CLIENT means there are no next + client records, i.e. this is the last one. + This is always LOGFILE_NO_CLIENT. */ +/* 20*/ le16 seq_number; /* On Win2k and presumably earlier, this is set + to zero every time the logfile is restarted + and it is incremented when the logfile is + closed at dismount time. Thus it is 0 when + dirty and 1 when clean. On WinXP and + presumably later, this is always 0. */ +/* 22*/ u8 reserved[6]; /* Reserved/alignment. */ +/* 28*/ le32 client_name_length;/* Length of client name in bytes. Should + always be 8. */ +/* 32*/ ntfschar client_name[64];/* Name of the client in Unicode. Should + always be "NTFS" with the remaining bytes + set to 0. */ +/* sizeof() = 160 (0xa0) bytes */ +} __attribute__ ((__packed__)) LOG_CLIENT_RECORD; + +extern bool ntfs_check_logfile(struct inode *log_vi, + RESTART_PAGE_HEADER **rp); + +extern bool ntfs_is_logfile_clean(struct inode *log_vi, + const RESTART_PAGE_HEADER *rp); + +extern bool ntfs_empty_logfile(struct inode *log_vi); + +#endif /* NTFS_RW */ + +#endif /* _LINUX_NTFS_LOGFILE_H */ |