Btt.h File Reference

Data Structures
struct	_EFI_BTT_INFO_BLOCK
struct	_EFI_BTT_MAP_ENTRY
struct	_EFI_BTT_FLOG

Macros
#define	EFI_BTT_ABSTRACTION_GUID
#define	EFI_BTT_ALIGNMENT   4096
#define	EFI_BTT_INFO_UNUSED_LEN   3968
#define	EFI_BTT_INFO_BLOCK_SIG_LEN   16
#define	EFI_BTT_INFO_BLOCK_FLAGS_ERROR   0x00000001
#define	EFI_BTT_INFO_BLOCK_MAJOR_VERSION   2
#define	EFI_BTT_INFO_BLOCK_MINOR_VERSION   0
#define	EFI_BTT_FLOG_ENTRY_ALIGNMENT   64

Typedefs
typedef struct _EFI_BTT_INFO_BLOCK	EFI_BTT_INFO_BLOCK
typedef struct _EFI_BTT_MAP_ENTRY	EFI_BTT_MAP_ENTRY
typedef struct _EFI_BTT_FLOG	EFI_BTT_FLOG

Variables
GUID	gEfiBttAbstractionGuid

Detailed Description

Block Translation Table (BTT) metadata layout definition.

BTT is a layout and set of rules for doing block I/O that provide powerfail write atomicity of a single block.

Copyright (c) 2017, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent

Revision Reference:

This metadata layout definition was introduced in UEFI Specification 2.7.

Macro Definition Documentation

#define EFI_BTT_ABSTRACTION_GUID

Value:

{ \
    0x18633bfc, 0x1735, 0x4217, { 0x8a, 0xc9, 0x17, 0x23, 0x92, 0x82, 0xd3, 0xf8 } \
  }

The BTT layout and behavior is described by the GUID as below.

#define EFI_BTT_ALIGNMENT   4096

#define EFI_BTT_FLOG_ENTRY_ALIGNMENT   64

Alignment of each flog structure

#define EFI_BTT_INFO_BLOCK_FLAGS_ERROR   0x00000001

Indicate inconsistent metadata or lost metadata due to unrecoverable media errors.

#define EFI_BTT_INFO_BLOCK_MAJOR_VERSION   2

#define EFI_BTT_INFO_BLOCK_MINOR_VERSION   0

#define EFI_BTT_INFO_BLOCK_SIG_LEN   16

#define EFI_BTT_INFO_UNUSED_LEN   3968

Typedef Documentation

typedef struct _EFI_BTT_FLOG EFI_BTT_FLOG

The BTT Flog is both a free list and a log. The Flog size is determined by the EFI_BTT_INFO_BLOCK.NFree which determines how many of these flog entries there are. The Flog location is the highest aligned address in the arena after space for the backup info block.

typedef struct _EFI_BTT_INFO_BLOCK EFI_BTT_INFO_BLOCK

Block Translation Table (BTT) Info Block

typedef struct _EFI_BTT_MAP_ENTRY EFI_BTT_MAP_ENTRY

BTT Map entry maps an LBA that indexes into the arena, to its actual location.

Variable Documentation

GUID gEfiBttAbstractionGuid