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/*++ BUILD Version: 0000 // Increment this if a change has global effects
Copyright (c) 1989 Microsoft Corporation
Module Name:
LfsDisk.h
Abstract:
This module defines the on-disk structures present in the log file.
Author:
Brian Andrew [BrianAn] 13-June-1991
Revision History:
IMPORTANT NOTE:
The Log File Service will by used on systems that require that on-disk
structures guarantee the natural alignment of all arithmetic quantities
up to and including quad-word (64-bit) numbers. Therefore, all Lfs
on-disk structures are quad-word aligned, etc.
--*/
#ifndef _LFSDISK_
#define _LFSDISK_
#define MINIMUM_LFS_PAGES 0x00000030
#define MINIMUM_LFS_CLIENTS 1
//
// The following macros are used to set and query with respect to the
// update sequence arrays.
//
#define UpdateSequenceStructureSize( MSH ) \
((((PMULTI_SECTOR_HEADER) (MSH))->UpdateSequenceArraySize - 1) * SEQUENCE_NUMBER_STRIDE)
#define UpdateSequenceArraySize( STRUCT_SIZE ) \
((STRUCT_SIZE) / SEQUENCE_NUMBER_STRIDE + 1)
#define FIRST_STRIDE \
(SEQUENCE_NUMBER_STRIDE - sizeof( UPDATE_SEQUENCE_NUMBER ))
//
// Log client ID. This is used to uniquely identify a client for a
// particular log file.
//
typedef struct _LFS_CLIENT_ID {
USHORT SeqNumber;
USHORT ClientIndex;
} LFS_CLIENT_ID, *PLFS_CLIENT_ID;
//
// Log Record Header. This is the header that begins every Log Record in
// the log file.
//
typedef struct _LFS_RECORD_HEADER {
//
// Log File Sequence Number of this log record.
//
LSN ThisLsn;
//
// The following fields are used to back link Lsn's. The ClientPrevious
// and ClientUndoNextLsn fields are used by a client to link his log
// records.
//
LSN ClientPreviousLsn;
LSN ClientUndoNextLsn;
//
// The following field is the size of data area for this record. The
// log record header will be padded if necessary to fill to a 64-bit
// boundary, so the client data will begin on a 64-bit boundary to
// insure that all of his data is 64-bit aligned. The below value
// has not been padded to 64 bits however.
//
ULONG ClientDataLength;
//
// Client ID. This identifies the owner of this log record. The owner
// is uniquely identified by his offset in the client array and the
// sequence number associated with that client record.
//
LFS_CLIENT_ID ClientId;
//
// This the Log Record type. This could be a commit protocol record,
// a client restart area or a client update record.
//
LFS_RECORD_TYPE RecordType;
//
// Transaction ID. This is used externally by a client (Transaction
// Manager) to group log file entries.
//
TRANSACTION_ID TransactionId;
//
// Log record flags.
//
USHORT Flags;
//
// Alignment field.
//
USHORT AlignWord;
} LFS_RECORD_HEADER, *PLFS_RECORD_HEADER;
#define LOG_RECORD_MULTI_PAGE (0x0001)
#define LFS_RECORD_HEADER_SIZE QuadAlign( sizeof( LFS_RECORD_HEADER ))
//
// Following are the version specific fields in the record page header.
//
typedef struct _LFS_UNPACKED_RECORD_PAGE {
//
// This gives us the offset of the free space in the page.
//
USHORT NextRecordOffset;
USHORT WordAlign;
//
// Reserved. The following array is reserved for possible future use.
//
USHORT Reserved;
//
// Update Sequence Array. Used to protect the page block.
//
UPDATE_SEQUENCE_ARRAY UpdateSequenceArray;
} LFS_UNPACKED_RECORD_PAGE, *PLFS_UNPACKED_RECORD_PAGE;
typedef struct _LFS_PACKED_RECORD_PAGE {
//
// This gives us the offset of the free space in the page.
//
USHORT NextRecordOffset;
USHORT WordAlign;
ULONG DWordAlign;
//
// The following is the Lsn for the last log record which ends on the page.
//
LSN LastEndLsn;
//
// Update Sequence Array. Used to protect the page block.
//
UPDATE_SEQUENCE_ARRAY UpdateSequenceArray;
} LFS_PACKED_RECORD_PAGE, *PLFS_PACKED_RECORD_PAGE;
//
// Log Record Page Header. This structure is present at the beginning of each
// log file page in the client record section.
//
typedef struct _LFS_RECORD_PAGE_HEADER {
//
// Cache multisector protection header.
//
MULTI_SECTOR_HEADER MultiSectorHeader;
union {
//
// Highest Lsn in this log file page. This field is only for
// regular log pages.
//
LSN LastLsn;
//
// Log file offset. This is for the tail copies and indicates the
// location in the file where the original lays. In this case the
// LastLsn field above can be obtained from the last ending Lsn
// field in the PACKED_RECORD_PAGE structure.
//
LONGLONG FileOffset;
} Copy;
//
// Page Header Flags. These are the same flags that are stored in the
// Lbcb->Flags field.
//
// LOG_PAGE_LOG_RECORD_END - Page contains the end of a log record
//
ULONG Flags;
//
// I/O Page Position. The following fields are used to determine
// where this log page resides within a Lfs I/O transfer.
//
USHORT PageCount;
USHORT PagePosition;
//
// The following is the difference between version 1.1 and earlier.
//
union {
LFS_UNPACKED_RECORD_PAGE Unpacked;
LFS_PACKED_RECORD_PAGE Packed;
} Header;
} LFS_RECORD_PAGE_HEADER, *PLFS_RECORD_PAGE_HEADER;
#define LOG_PAGE_LOG_RECORD_END (0x00000001)
#define LFS_UNPACKED_RECORD_PAGE_HEADER_SIZE ( \
FIELD_OFFSET( LFS_RECORD_PAGE_HEADER, Header.Unpacked.UpdateSequenceArray ) \
)
#define LFS_PACKED_RECORD_PAGE_HEADER_SIZE ( \
FIELD_OFFSET( LFS_RECORD_PAGE_HEADER, Header.Packed.UpdateSequenceArray ) \
)
//
// Log Restart Page Header. This structure is at the head of the restart
// areas in a log file.
//
typedef struct _LFS_RESTART_PAGE_HEADER {
//
// Cache multisector protection header.
//
MULTI_SECTOR_HEADER MultiSectorHeader;
//
// This is the last Lsn found by checkdisk for this volume.
//
LSN ChkDskLsn;
//
// System page size. This is the page size of the system which
// initialized the log file. Unless the log file has been gracefully
// shutdown (there are no clients with restart areas), it is a fatal
// error to attempt to write to a log file on a system with a differen
// page size.
//
ULONG SystemPageSize;
//
// Log Page Size. This is the log page size used for this log file.
// The entire Lfs restart area must fit on a single log page.
//
ULONG LogPageSize;
//
// Lfs restart area offset. This is the offset from the start of this
// structure to the Lfs restart area.
//
USHORT RestartOffset;
//
// The indicates major and minor versions. Note that the pre-release versions
// have -1 in both positions. Major version 0 indicates the transition
// from Beta to USA support.
//
// Major Version
//
// -1 Beta Version
// 0 Transition
// 1 Update sequence support.
//
SHORT MinorVersion;
SHORT MajorVersion;
//
// Update Sequence Array. Used to protect the page block.
//
UPDATE_SEQUENCE_ARRAY UpdateSequenceArray;
} LFS_RESTART_PAGE_HEADER, *PLFS_RESTART_PAGE_HEADER;
#define LFS_RESTART_PAGE_HEADER_SIZE ( \
FIELD_OFFSET( LFS_RESTART_PAGE_HEADER, UpdateSequenceArray ) \
)
//
// Id strings for the page headers.
//
#define LFS_SIGNATURE_RESTART_PAGE "RSTR"
#define LFS_SIGNATURE_RESTART_PAGE_ULONG 0x52545352
#define LFS_SIGNATURE_RECORD_PAGE "RCRD"
#define LFS_SIGNATURE_RECORD_PAGE_ULONG 0x44524352
#define LFS_SIGNATURE_BAD_USA "BAAD"
#define LFS_SIGNATURE_BAD_USA_ULONG 0x44414142
#define LFS_SIGNATURE_MODIFIED "CHKD"
#define LFS_SIGNATURE_MODIFIED_ULONG 0x444b4843
#define LFS_SIGNATURE_UNINITIALIZED "\377\377\377\377"
#define LFS_SIGNATURE_UNINITIALIZED_ULONG 0xffffffff
//
// Log Client Record. A log client record exists for each client user of
// the log file. One of these is in each Lfs restart area.
//
#define LFS_NO_CLIENT 0xffff
#define LFS_CLIENT_NAME_MAX 64
typedef struct _LFS_CLIENT_RECORD {
//
// Oldest Lsn. This is the oldest Lsn that this client requires to
// be in the log file.
//
LSN OldestLsn;
//
// Client Restart Lsn. This is the Lsn of the latest client restart
// area written to the disk. A reserved Lsn will indicate that no
// restart area exists for this client.
//
LSN ClientRestartLsn;
//
//
// Previous/Next client area. These are the indexes into an array of
// Log Client Records for the previous and next client records.
//
USHORT PrevClient;
USHORT NextClient;
//
// Sequence Number. Incremented whenever this record is reused. This
// will happen whenever a client opens (reopens) the log file and has
// no current restart area.
USHORT SeqNumber;
//
// Alignment field.
//
USHORT AlignWord;
//
// Align the entire record.
//
ULONG AlignDWord;
//
// The following fields are used to describe the client name. A client
// name consists of at most 32 Unicode character (64 bytes). The Log
// file service will treat client names as case sensitive.
//
ULONG ClientNameLength;
WCHAR ClientName[LFS_CLIENT_NAME_MAX];
} LFS_CLIENT_RECORD, *PLFS_CLIENT_RECORD;
//
// Lfs Restart Area. Two copies of these will exist at the beginning of the
// log file.
//
typedef struct _LFS_RESTART_AREA {
//
// Current Lsn. This is periodic snapshot of the current logical end of
// log file to facilitate restart.
//
LSN CurrentLsn;
//
// Number of Clients. This is the maximum number of clients supported
// for this log file.
//
USHORT LogClients;
//
// The following are indexes into the client record arrays. The client
// records are linked into two lists. A free list of client records and
// an in-use list of records.
//
USHORT ClientFreeList;
USHORT ClientInUseList;
//
// Flag field.
//
// RESTART_SINGLE_PAGE_IO All log pages written 1 by 1
//
USHORT Flags;
//
// The following is the number of bits to use for the sequence number.
//
ULONG SeqNumberBits;
//
// Length of this restart area.
//
USHORT RestartAreaLength;
//
// Offset from the start of this structure to the client array.
// Ignored in versions prior to 1.1
//
USHORT ClientArrayOffset;
//
// Usable log file size. We will stop sharing the value in the page header.
//
LONGLONG FileSize;
//
// DataLength of last Lsn. This doesn't include the length of
// the Lfs header.
//
ULONG LastLsnDataLength;
//
// The following apply to log pages. This is the log page data offset and
// the length of the log record header. Ignored in versions prior to 1.1
//
USHORT RecordHeaderLength;
USHORT LogPageDataOffset;
//
// Client data.
//
LFS_CLIENT_RECORD LogClientArray[1];
} LFS_RESTART_AREA, *PLFS_RESTART_AREA;
#define RESTART_SINGLE_PAGE_IO (0x0001)
#define LFS_RESTART_AREA_SIZE (FIELD_OFFSET( LFS_RESTART_AREA, LogClientArray ))
#endif // _LFSDISK_
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