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