Adding upstream version 6.9.7.upstream/6.9.7

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1298 insertions, 0 deletions

diff --git a/drivers/md/dm-vdo/encodings.h b/drivers/md/dm-vdo/encodings.h
new file mode 100644
index 0000000000..e5ff2b0aaa
--- /dev/null
+++ b/drivers/md/dm-vdo/encodings.h
@@ -0,0 +1,1298 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef VDO_ENCODINGS_H
+#define VDO_ENCODINGS_H
+
+#include <linux/blk_types.h>
+#include <linux/crc32.h>
+#include <linux/limits.h>
+#include <linux/uuid.h>
+
+#include "numeric.h"
+
+#include "constants.h"
+#include "types.h"
+
+/*
+ * An in-memory representation of a version number for versioned structures on disk.
+ *
+ * A version number consists of two portions, a major version and a minor version. Any format
+ * change which does not require an explicit upgrade step from the previous version should
+ * increment the minor version. Any format change which either requires an explicit upgrade step,
+ * or is wholly incompatible (i.e. can not be upgraded to), should increment the major version, and
+ * set the minor version to 0.
+ */
+struct version_number {
+	u32 major_version;
+	u32 minor_version;
+};
+
+/*
+ * A packed, machine-independent, on-disk representation of a version_number. Both fields are
+ * stored in little-endian byte order.
+ */
+struct packed_version_number {
+	__le32 major_version;
+	__le32 minor_version;
+} __packed;
+
+/* The registry of component ids for use in headers */
+#define VDO_SUPER_BLOCK 0
+#define VDO_LAYOUT 1
+#define VDO_RECOVERY_JOURNAL 2
+#define VDO_SLAB_DEPOT 3
+#define VDO_BLOCK_MAP 4
+#define VDO_GEOMETRY_BLOCK 5
+
+/* The header for versioned data stored on disk. */
+struct header {
+	u32 id; /* The component this is a header for */
+	struct version_number version; /* The version of the data format */
+	size_t size; /* The size of the data following this header */
+};
+
+/* A packed, machine-independent, on-disk representation of a component header. */
+struct packed_header {
+	__le32 id;
+	struct packed_version_number version;
+	__le64 size;
+} __packed;
+
+enum {
+	VDO_GEOMETRY_BLOCK_LOCATION = 0,
+	VDO_GEOMETRY_MAGIC_NUMBER_SIZE = 8,
+	VDO_DEFAULT_GEOMETRY_BLOCK_VERSION = 5,
+};
+
+struct index_config {
+	u32 mem;
+	u32 unused;
+	bool sparse;
+} __packed;
+
+enum volume_region_id {
+	VDO_INDEX_REGION = 0,
+	VDO_DATA_REGION = 1,
+	VDO_VOLUME_REGION_COUNT,
+};
+
+struct volume_region {
+	/* The ID of the region */
+	enum volume_region_id id;
+	/*
+	 * The absolute starting offset on the device. The region continues until the next region
+	 * begins.
+	 */
+	physical_block_number_t start_block;
+} __packed;
+
+struct volume_geometry {
+	/* For backwards compatibility */
+	u32 unused;
+	/* The nonce of this volume */
+	nonce_t nonce;
+	/* The uuid of this volume */
+	uuid_t uuid;
+	/* The block offset to be applied to bios */
+	block_count_t bio_offset;
+	/* The regions in ID order */
+	struct volume_region regions[VDO_VOLUME_REGION_COUNT];
+	/* The index config */
+	struct index_config index_config;
+} __packed;
+
+/* This volume geometry struct is used for sizing only */
+struct volume_geometry_4_0 {
+	/* For backwards compatibility */
+	u32 unused;
+	/* The nonce of this volume */
+	nonce_t nonce;
+	/* The uuid of this volume */
+	uuid_t uuid;
+	/* The regions in ID order */
+	struct volume_region regions[VDO_VOLUME_REGION_COUNT];
+	/* The index config */
+	struct index_config index_config;
+} __packed;
+
+extern const u8 VDO_GEOMETRY_MAGIC_NUMBER[VDO_GEOMETRY_MAGIC_NUMBER_SIZE + 1];
+
+/**
+ * DOC: Block map entries
+ *
+ * The entry for each logical block in the block map is encoded into five bytes, which saves space
+ * in both the on-disk and in-memory layouts. It consists of the 36 low-order bits of a
+ * physical_block_number_t (addressing 256 terabytes with a 4KB block size) and a 4-bit encoding of
+ * a block_mapping_state.
+ *
+ * Of the 8 high bits of the 5-byte structure:
+ *
+ * Bits 7..4: The four highest bits of the 36-bit physical block number
+ * Bits 3..0: The 4-bit block_mapping_state
+ *
+ * The following 4 bytes are the low order bytes of the physical block number, in little-endian
+ * order.
+ *
+ * Conversion functions to and from a data location are provided.
+ */
+struct block_map_entry {
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	unsigned mapping_state : 4;
+	unsigned pbn_high_nibble : 4;
+#else
+	unsigned pbn_high_nibble : 4;
+	unsigned mapping_state : 4;
+#endif
+
+	__le32 pbn_low_word;
+} __packed;
+
+struct block_map_page_header {
+	__le64 nonce;
+	__le64 pbn;
+
+	/* May be non-zero on disk */
+	u8 unused_long_word[8];
+
+	/* Whether this page has been written twice to disk */
+	bool initialized;
+
+	/* Always zero on disk */
+	u8 unused_byte1;
+
+	/* May be non-zero on disk */
+	u8 unused_byte2;
+	u8 unused_byte3;
+} __packed;
+
+struct block_map_page {
+	struct packed_version_number version;
+	struct block_map_page_header header;
+	struct block_map_entry entries[];
+} __packed;
+
+enum block_map_page_validity {
+	VDO_BLOCK_MAP_PAGE_VALID,
+	VDO_BLOCK_MAP_PAGE_INVALID,
+	/* Valid page found in the wrong location on disk */
+	VDO_BLOCK_MAP_PAGE_BAD,
+};
+
+struct block_map_state_2_0 {
+	physical_block_number_t flat_page_origin;
+	block_count_t flat_page_count;
+	physical_block_number_t root_origin;
+	block_count_t root_count;
+} __packed;
+
+struct boundary {
+	page_number_t levels[VDO_BLOCK_MAP_TREE_HEIGHT];
+};
+
+extern const struct header VDO_BLOCK_MAP_HEADER_2_0;
+
+/* The state of the recovery journal as encoded in the VDO super block. */
+struct recovery_journal_state_7_0 {
+	/* Sequence number to start the journal */
+	sequence_number_t journal_start;
+	/* Number of logical blocks used by VDO */
+	block_count_t logical_blocks_used;
+	/* Number of block map pages allocated */
+	block_count_t block_map_data_blocks;
+} __packed;
+
+extern const struct header VDO_RECOVERY_JOURNAL_HEADER_7_0;
+
+typedef u16 journal_entry_count_t;
+
+/*
+ * A recovery journal entry stores three physical locations: a data location that is the value of a
+ * single mapping in the block map tree, and the two locations of the block map pages and slots
+ * that are acquiring and releasing a reference to the location. The journal entry also stores an
+ * operation code that says whether the mapping is for a logical block or for the block map tree
+ * itself.
+ */
+struct recovery_journal_entry {
+	struct block_map_slot slot;
+	struct data_location mapping;
+	struct data_location unmapping;
+	enum journal_operation operation;
+};
+
+/* The packed, on-disk representation of a recovery journal entry. */
+struct packed_recovery_journal_entry {
+	/*
+	 * In little-endian bit order:
+	 * Bits 15..12: The four highest bits of the 36-bit physical block number of the block map
+	 * tree page
+	 * Bits 11..2: The 10-bit block map page slot number
+	 * Bit 1..0: The journal_operation of the entry (this actually only requires 1 bit, but
+	 *           it is convenient to keep the extra bit as part of this field.
+	 */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	unsigned operation : 2;
+	unsigned slot_low : 6;
+	unsigned slot_high : 4;
+	unsigned pbn_high_nibble : 4;
+#else
+	unsigned slot_low : 6;
+	unsigned operation : 2;
+	unsigned pbn_high_nibble : 4;
+	unsigned slot_high : 4;
+#endif
+
+	/*
+	 * Bits 47..16: The 32 low-order bits of the block map page PBN, in little-endian byte
+	 * order
+	 */
+	__le32 pbn_low_word;
+
+	/*
+	 * Bits 87..48: The five-byte block map entry encoding the location that will be stored in
+	 * the block map page slot
+	 */
+	struct block_map_entry mapping;
+
+	/*
+	 * Bits 127..88: The five-byte block map entry encoding the location that was stored in the
+	 * block map page slot
+	 */
+	struct block_map_entry unmapping;
+} __packed;
+
+/* The packed, on-disk representation of an old format recovery journal entry. */
+struct packed_recovery_journal_entry_1 {
+	/*
+	 * In little-endian bit order:
+	 * Bits 15..12: The four highest bits of the 36-bit physical block number of the block map
+	 *              tree page
+	 * Bits 11..2: The 10-bit block map page slot number
+	 * Bits 1..0: The 2-bit journal_operation of the entry
+	 *
+	 */
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	unsigned operation : 2;
+	unsigned slot_low : 6;
+	unsigned slot_high : 4;
+	unsigned pbn_high_nibble : 4;
+#else
+	unsigned slot_low : 6;
+	unsigned operation : 2;
+	unsigned pbn_high_nibble : 4;
+	unsigned slot_high : 4;
+#endif
+
+	/*
+	 * Bits 47..16: The 32 low-order bits of the block map page PBN, in little-endian byte
+	 * order
+	 */
+	__le32 pbn_low_word;
+
+	/*
+	 * Bits 87..48: The five-byte block map entry encoding the location that was or will be
+	 * stored in the block map page slot
+	 */
+	struct block_map_entry block_map_entry;
+} __packed;
+
+enum journal_operation_1 {
+	VDO_JOURNAL_DATA_DECREMENT = 0,
+	VDO_JOURNAL_DATA_INCREMENT = 1,
+	VDO_JOURNAL_BLOCK_MAP_DECREMENT = 2,
+	VDO_JOURNAL_BLOCK_MAP_INCREMENT = 3,
+} __packed;
+
+struct recovery_block_header {
+	sequence_number_t block_map_head; /* Block map head sequence number */
+	sequence_number_t slab_journal_head; /* Slab journal head seq. number */
+	sequence_number_t sequence_number; /* Sequence number for this block */
+	nonce_t nonce; /* A given VDO instance's nonce */
+	block_count_t logical_blocks_used; /* Logical blocks in use */
+	block_count_t block_map_data_blocks; /* Allocated block map pages */
+	journal_entry_count_t entry_count; /* Number of entries written */
+	u8 check_byte; /* The protection check byte */
+	u8 recovery_count; /* Number of recoveries completed */
+	enum vdo_metadata_type metadata_type; /* Metadata type */
+};
+
+/*
+ * The packed, on-disk representation of a recovery journal block header. All fields are kept in
+ * little-endian byte order.
+ */
+struct packed_journal_header {
+	/* Block map head 64-bit sequence number */
+	__le64 block_map_head;
+
+	/* Slab journal head 64-bit sequence number */
+	__le64 slab_journal_head;
+
+	/* The 64-bit sequence number for this block */
+	__le64 sequence_number;
+
+	/* A given VDO instance's 64-bit nonce */
+	__le64 nonce;
+
+	/* 8-bit metadata type (should always be one for the recovery journal) */
+	u8 metadata_type;
+
+	/* 16-bit count of the entries encoded in the block */
+	__le16 entry_count;
+
+	/* 64-bit count of the logical blocks used when this block was opened */
+	__le64 logical_blocks_used;
+
+	/* 64-bit count of the block map blocks used when this block was opened */
+	__le64 block_map_data_blocks;
+
+	/* The protection check byte */
+	u8 check_byte;
+
+	/* The number of recoveries completed */
+	u8 recovery_count;
+} __packed;
+
+struct packed_journal_sector {
+	/* The protection check byte */
+	u8 check_byte;
+
+	/* The number of recoveries completed */
+	u8 recovery_count;
+
+	/* The number of entries in this sector */
+	u8 entry_count;
+
+	/* Journal entries for this sector */
+	struct packed_recovery_journal_entry entries[];
+} __packed;
+
+enum {
+	/* The number of entries in each sector (except the last) when filled */
+	RECOVERY_JOURNAL_ENTRIES_PER_SECTOR =
+		((VDO_SECTOR_SIZE - sizeof(struct packed_journal_sector)) /
+		 sizeof(struct packed_recovery_journal_entry)),
+	RECOVERY_JOURNAL_ENTRIES_PER_BLOCK = RECOVERY_JOURNAL_ENTRIES_PER_SECTOR * 7,
+	/* The number of entries in a v1 recovery journal block. */
+	RECOVERY_JOURNAL_1_ENTRIES_PER_BLOCK = 311,
+	/* The number of entries in each v1 sector (except the last) when filled */
+	RECOVERY_JOURNAL_1_ENTRIES_PER_SECTOR =
+		((VDO_SECTOR_SIZE - sizeof(struct packed_journal_sector)) /
+		 sizeof(struct packed_recovery_journal_entry_1)),
+	/* The number of entries in the last sector when a block is full */
+	RECOVERY_JOURNAL_1_ENTRIES_IN_LAST_SECTOR =
+		(RECOVERY_JOURNAL_1_ENTRIES_PER_BLOCK % RECOVERY_JOURNAL_1_ENTRIES_PER_SECTOR),
+};
+
+/* A type representing a reference count of a block. */
+typedef u8 vdo_refcount_t;
+
+/* The absolute position of an entry in a recovery journal or slab journal. */
+struct journal_point {
+	sequence_number_t sequence_number;
+	journal_entry_count_t entry_count;
+};
+
+/* A packed, platform-independent encoding of a struct journal_point. */
+struct packed_journal_point {
+	/*
+	 * The packed representation is the little-endian 64-bit representation of the low-order 48
+	 * bits of the sequence number, shifted up 16 bits, or'ed with the 16-bit entry count.
+	 *
+	 * Very long-term, the top 16 bits of the sequence number may not always be zero, as this
+	 * encoding assumes--see BZ 1523240.
+	 */
+	__le64 encoded_point;
+} __packed;
+
+/* Special vdo_refcount_t values. */
+#define EMPTY_REFERENCE_COUNT 0
+enum {
+	MAXIMUM_REFERENCE_COUNT = 254,
+	PROVISIONAL_REFERENCE_COUNT = 255,
+};
+
+enum {
+	COUNTS_PER_SECTOR =
+		((VDO_SECTOR_SIZE - sizeof(struct packed_journal_point)) / sizeof(vdo_refcount_t)),
+	COUNTS_PER_BLOCK = COUNTS_PER_SECTOR * VDO_SECTORS_PER_BLOCK,
+};
+
+/* The format of each sector of a reference_block on disk. */
+struct packed_reference_sector {
+	struct packed_journal_point commit_point;
+	vdo_refcount_t counts[COUNTS_PER_SECTOR];
+} __packed;
+
+struct packed_reference_block {
+	struct packed_reference_sector sectors[VDO_SECTORS_PER_BLOCK];
+};
+
+struct slab_depot_state_2_0 {
+	struct slab_config slab_config;
+	physical_block_number_t first_block;
+	physical_block_number_t last_block;
+	zone_count_t zone_count;
+} __packed;
+
+extern const struct header VDO_SLAB_DEPOT_HEADER_2_0;
+
+/*
+ * vdo_slab journal blocks may have one of two formats, depending upon whether or not any of the
+ * entries in the block are block map increments. Since the steady state for a VDO is that all of
+ * the necessary block map pages will be allocated, most slab journal blocks will have only data
+ * entries. Such blocks can hold more entries, hence the two formats.
+ */
+
+/* A single slab journal entry */
+struct slab_journal_entry {
+	slab_block_number sbn;
+	enum journal_operation operation;
+	bool increment;
+};
+
+/* A single slab journal entry in its on-disk form */
+typedef struct {
+	u8 offset_low8;
+	u8 offset_mid8;
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	unsigned offset_high7 : 7;
+	unsigned increment : 1;
+#else
+	unsigned increment : 1;
+	unsigned offset_high7 : 7;
+#endif
+} __packed packed_slab_journal_entry;
+
+/* The unpacked representation of the header of a slab journal block */
+struct slab_journal_block_header {
+	/* Sequence number for head of journal */
+	sequence_number_t head;
+	/* Sequence number for this block */
+	sequence_number_t sequence_number;
+	/* The nonce for a given VDO instance */
+	nonce_t nonce;
+	/* Recovery journal point for last entry */
+	struct journal_point recovery_point;
+	/* Metadata type */
+	enum vdo_metadata_type metadata_type;
+	/* Whether this block contains block map increments */
+	bool has_block_map_increments;
+	/* The number of entries in the block */
+	journal_entry_count_t entry_count;
+};
+
+/*
+ * The packed, on-disk representation of a slab journal block header. All fields are kept in
+ * little-endian byte order.
+ */
+struct packed_slab_journal_block_header {
+	/* 64-bit sequence number for head of journal */
+	__le64 head;
+	/* 64-bit sequence number for this block */
+	__le64 sequence_number;
+	/* Recovery journal point for the last entry, packed into 64 bits */
+	struct packed_journal_point recovery_point;
+	/* The 64-bit nonce for a given VDO instance */
+	__le64 nonce;
+	/* 8-bit metadata type (should always be two, for the slab journal) */
+	u8 metadata_type;
+	/* Whether this block contains block map increments */
+	bool has_block_map_increments;
+	/* 16-bit count of the entries encoded in the block */
+	__le16 entry_count;
+} __packed;
+
+enum {
+	VDO_SLAB_JOURNAL_PAYLOAD_SIZE =
+		VDO_BLOCK_SIZE - sizeof(struct packed_slab_journal_block_header),
+	VDO_SLAB_JOURNAL_FULL_ENTRIES_PER_BLOCK = (VDO_SLAB_JOURNAL_PAYLOAD_SIZE * 8) / 25,
+	VDO_SLAB_JOURNAL_ENTRY_TYPES_SIZE =
+		((VDO_SLAB_JOURNAL_FULL_ENTRIES_PER_BLOCK - 1) / 8) + 1,
+	VDO_SLAB_JOURNAL_ENTRIES_PER_BLOCK =
+		(VDO_SLAB_JOURNAL_PAYLOAD_SIZE / sizeof(packed_slab_journal_entry)),
+};
+
+/* The payload of a slab journal block which has block map increments */
+struct full_slab_journal_entries {
+	/* The entries themselves */
+	packed_slab_journal_entry entries[VDO_SLAB_JOURNAL_FULL_ENTRIES_PER_BLOCK];
+	/* The bit map indicating which entries are block map increments */
+	u8 entry_types[VDO_SLAB_JOURNAL_ENTRY_TYPES_SIZE];
+} __packed;
+
+typedef union {
+	/* Entries which include block map increments */
+	struct full_slab_journal_entries full_entries;
+	/* Entries which are only data updates */
+	packed_slab_journal_entry entries[VDO_SLAB_JOURNAL_ENTRIES_PER_BLOCK];
+	/* Ensure the payload fills to the end of the block */
+	u8 space[VDO_SLAB_JOURNAL_PAYLOAD_SIZE];
+} __packed slab_journal_payload;
+
+struct packed_slab_journal_block {
+	struct packed_slab_journal_block_header header;
+	slab_journal_payload payload;
+} __packed;
+
+/* The offset of a slab journal tail block. */
+typedef u8 tail_block_offset_t;
+
+struct slab_summary_entry {
+	/* Bits 7..0: The offset of the tail block within the slab journal */
+	tail_block_offset_t tail_block_offset;
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	/* Bits 13..8: A hint about the fullness of the slab */
+	unsigned int fullness_hint : 6;
+	/* Bit 14: Whether the ref_counts must be loaded from the layer */
+	unsigned int load_ref_counts : 1;
+	/* Bit 15: The believed cleanliness of this slab */
+	unsigned int is_dirty : 1;
+#else
+	/* Bit 15: The believed cleanliness of this slab */
+	unsigned int is_dirty : 1;
+	/* Bit 14: Whether the ref_counts must be loaded from the layer */
+	unsigned int load_ref_counts : 1;
+	/* Bits 13..8: A hint about the fullness of the slab */
+	unsigned int fullness_hint : 6;
+#endif
+} __packed;
+
+enum {
+	VDO_SLAB_SUMMARY_FULLNESS_HINT_BITS = 6,
+	VDO_SLAB_SUMMARY_ENTRIES_PER_BLOCK = VDO_BLOCK_SIZE / sizeof(struct slab_summary_entry),
+	VDO_SLAB_SUMMARY_BLOCKS_PER_ZONE = MAX_VDO_SLABS / VDO_SLAB_SUMMARY_ENTRIES_PER_BLOCK,
+	VDO_SLAB_SUMMARY_BLOCKS = VDO_SLAB_SUMMARY_BLOCKS_PER_ZONE * MAX_VDO_PHYSICAL_ZONES,
+};
+
+struct layout {
+	physical_block_number_t start;
+	block_count_t size;
+	physical_block_number_t first_free;
+	physical_block_number_t last_free;
+	size_t num_partitions;
+	struct partition *head;
+};
+
+struct partition {
+	enum partition_id id; /* The id of this partition */
+	physical_block_number_t offset; /* The offset into the layout of this partition */
+	block_count_t count; /* The number of blocks in the partition */
+	struct partition *next; /* A pointer to the next partition in the layout */
+};
+
+struct layout_3_0 {
+	physical_block_number_t first_free;
+	physical_block_number_t last_free;
+	u8 partition_count;
+} __packed;
+
+struct partition_3_0 {
+	enum partition_id id;
+	physical_block_number_t offset;
+	physical_block_number_t base; /* unused but retained for backwards compatibility */
+	block_count_t count;
+} __packed;
+
+/*
+ * The configuration of the VDO service.
+ */
+struct vdo_config {
+	block_count_t logical_blocks; /* number of logical blocks */
+	block_count_t physical_blocks; /* number of physical blocks */
+	block_count_t slab_size; /* number of blocks in a slab */
+	block_count_t recovery_journal_size; /* number of recovery journal blocks */
+	block_count_t slab_journal_blocks; /* number of slab journal blocks */
+};
+
+/* This is the structure that captures the vdo fields saved as a super block component. */
+struct vdo_component {
+	enum vdo_state state;
+	u64 complete_recoveries;
+	u64 read_only_recoveries;
+	struct vdo_config config;
+	nonce_t nonce;
+};
+
+/*
+ * A packed, machine-independent, on-disk representation of the vdo_config in the VDO component
+ * data in the super block.
+ */
+struct packed_vdo_config {
+	__le64 logical_blocks;
+	__le64 physical_blocks;
+	__le64 slab_size;
+	__le64 recovery_journal_size;
+	__le64 slab_journal_blocks;
+} __packed;
+
+/*
+ * A packed, machine-independent, on-disk representation of version 41.0 of the VDO component data
+ * in the super block.
+ */
+struct packed_vdo_component_41_0 {
+	__le32 state;
+	__le64 complete_recoveries;
+	__le64 read_only_recoveries;
+	struct packed_vdo_config config;
+	__le64 nonce;
+} __packed;
+
+/*
+ * The version of the on-disk format of a VDO volume. This should be incremented any time the
+ * on-disk representation of any VDO structure changes. Changes which require only online upgrade
+ * steps should increment the minor version. Changes which require an offline upgrade or which can
+ * not be upgraded to at all should increment the major version and set the minor version to 0.
+ */
+extern const struct version_number VDO_VOLUME_VERSION_67_0;
+
+enum {
+	VDO_ENCODED_HEADER_SIZE = sizeof(struct packed_header),
+	BLOCK_MAP_COMPONENT_ENCODED_SIZE =
+		VDO_ENCODED_HEADER_SIZE + sizeof(struct block_map_state_2_0),
+	RECOVERY_JOURNAL_COMPONENT_ENCODED_SIZE =
+		VDO_ENCODED_HEADER_SIZE + sizeof(struct recovery_journal_state_7_0),
+	SLAB_DEPOT_COMPONENT_ENCODED_SIZE =
+		VDO_ENCODED_HEADER_SIZE + sizeof(struct slab_depot_state_2_0),
+	VDO_PARTITION_COUNT = 4,
+	VDO_LAYOUT_ENCODED_SIZE = (VDO_ENCODED_HEADER_SIZE +
+				   sizeof(struct layout_3_0) +
+				   (sizeof(struct partition_3_0) * VDO_PARTITION_COUNT)),
+	VDO_SUPER_BLOCK_FIXED_SIZE = VDO_ENCODED_HEADER_SIZE + sizeof(u32),
+	VDO_MAX_COMPONENT_DATA_SIZE = VDO_SECTOR_SIZE - VDO_SUPER_BLOCK_FIXED_SIZE,
+	VDO_COMPONENT_ENCODED_SIZE =
+		(sizeof(struct packed_version_number) + sizeof(struct packed_vdo_component_41_0)),
+	VDO_COMPONENT_DATA_OFFSET = VDO_ENCODED_HEADER_SIZE,
+	VDO_COMPONENT_DATA_SIZE = (sizeof(u32) +
+				   sizeof(struct packed_version_number) +
+				   VDO_COMPONENT_ENCODED_SIZE +
+				   VDO_LAYOUT_ENCODED_SIZE +
+				   RECOVERY_JOURNAL_COMPONENT_ENCODED_SIZE +
+				   SLAB_DEPOT_COMPONENT_ENCODED_SIZE +
+				   BLOCK_MAP_COMPONENT_ENCODED_SIZE),
+};
+
+/* The entirety of the component data encoded in the VDO super block. */
+struct vdo_component_states {
+	/* For backwards compatibility */
+	u32 unused;
+
+	/* The VDO volume version */
+	struct version_number volume_version;
+
+	/* Components */
+	struct vdo_component vdo;
+	struct block_map_state_2_0 block_map;
+	struct recovery_journal_state_7_0 recovery_journal;
+	struct slab_depot_state_2_0 slab_depot;
+
+	/* Our partitioning of the underlying storage */
+	struct layout layout;
+};
+
+/**
+ * vdo_are_same_version() - Check whether two version numbers are the same.
+ * @version_a: The first version.
+ * @version_b: The second version.
+ *
+ * Return: true if the two versions are the same.
+ */
+static inline bool vdo_are_same_version(struct version_number version_a,
+					struct version_number version_b)
+{
+	return ((version_a.major_version == version_b.major_version) &&
+		(version_a.minor_version == version_b.minor_version));
+}
+
+/**
+ * vdo_is_upgradable_version() - Check whether an actual version is upgradable to an expected
+ *                               version.
+ * @expected_version: The expected version.
+ * @actual_version: The version being validated.
+ *
+ * An actual version is upgradable if its major number is expected but its minor number differs,
+ * and the expected version's minor number is greater than the actual version's minor number.
+ *
+ * Return: true if the actual version is upgradable.
+ */
+static inline bool vdo_is_upgradable_version(struct version_number expected_version,
+					     struct version_number actual_version)
+{
+	return ((expected_version.major_version == actual_version.major_version) &&
+		(expected_version.minor_version > actual_version.minor_version));
+}
+
+int __must_check vdo_validate_header(const struct header *expected_header,
+				     const struct header *actual_header, bool exact_size,
+				     const char *component_name);
+
+void vdo_encode_header(u8 *buffer, size_t *offset, const struct header *header);
+void vdo_decode_header(u8 *buffer, size_t *offset, struct header *header);
+
+/**
+ * vdo_pack_version_number() - Convert a version_number to its packed on-disk representation.
+ * @version: The version number to convert.
+ *
+ * Return: the platform-independent representation of the version
+ */
+static inline struct packed_version_number vdo_pack_version_number(struct version_number version)
+{
+	return (struct packed_version_number) {
+		.major_version = __cpu_to_le32(version.major_version),
+		.minor_version = __cpu_to_le32(version.minor_version),
+	};
+}
+
+/**
+ * vdo_unpack_version_number() - Convert a packed_version_number to its native in-memory
+ *                               representation.
+ * @version: The version number to convert.
+ *
+ * Return: The platform-independent representation of the version.
+ */
+static inline struct version_number vdo_unpack_version_number(struct packed_version_number version)
+{
+	return (struct version_number) {
+		.major_version = __le32_to_cpu(version.major_version),
+		.minor_version = __le32_to_cpu(version.minor_version),
+	};
+}
+
+/**
+ * vdo_pack_header() - Convert a component header to its packed on-disk representation.
+ * @header: The header to convert.
+ *
+ * Return: the platform-independent representation of the header
+ */
+static inline struct packed_header vdo_pack_header(const struct header *header)
+{
+	return (struct packed_header) {
+		.id = __cpu_to_le32(header->id),
+		.version = vdo_pack_version_number(header->version),
+		.size = __cpu_to_le64(header->size),
+	};
+}
+
+/**
+ * vdo_unpack_header() - Convert a packed_header to its native in-memory representation.
+ * @header: The header to convert.
+ *
+ * Return: The platform-independent representation of the version.
+ */
+static inline struct header vdo_unpack_header(const struct packed_header *header)
+{
+	return (struct header) {
+		.id = __le32_to_cpu(header->id),
+		.version = vdo_unpack_version_number(header->version),
+		.size = __le64_to_cpu(header->size),
+	};
+}
+
+/**
+ * vdo_get_index_region_start() - Get the start of the index region from a geometry.
+ * @geometry: The geometry.
+ *
+ * Return: The start of the index region.
+ */
+static inline physical_block_number_t __must_check
+vdo_get_index_region_start(struct volume_geometry geometry)
+{
+	return geometry.regions[VDO_INDEX_REGION].start_block;
+}
+
+/**
+ * vdo_get_data_region_start() - Get the start of the data region from a geometry.
+ * @geometry: The geometry.
+ *
+ * Return: The start of the data region.
+ */
+static inline physical_block_number_t __must_check
+vdo_get_data_region_start(struct volume_geometry geometry)
+{
+	return geometry.regions[VDO_DATA_REGION].start_block;
+}
+
+/**
+ * vdo_get_index_region_size() - Get the size of the index region from a geometry.
+ * @geometry: The geometry.
+ *
+ * Return: The size of the index region.
+ */
+static inline physical_block_number_t __must_check
+vdo_get_index_region_size(struct volume_geometry geometry)
+{
+	return vdo_get_data_region_start(geometry) -
+		vdo_get_index_region_start(geometry);
+}
+
+int __must_check vdo_parse_geometry_block(unsigned char *block,
+					  struct volume_geometry *geometry);
+
+static inline bool vdo_is_state_compressed(const enum block_mapping_state mapping_state)
+{
+	return (mapping_state > VDO_MAPPING_STATE_UNCOMPRESSED);
+}
+
+static inline struct block_map_entry
+vdo_pack_block_map_entry(physical_block_number_t pbn, enum block_mapping_state mapping_state)
+{
+	return (struct block_map_entry) {
+		.mapping_state = (mapping_state & 0x0F),
+		.pbn_high_nibble = ((pbn >> 32) & 0x0F),
+		.pbn_low_word = __cpu_to_le32(pbn & UINT_MAX),
+	};
+}
+
+static inline struct data_location vdo_unpack_block_map_entry(const struct block_map_entry *entry)
+{
+	physical_block_number_t low32 = __le32_to_cpu(entry->pbn_low_word);
+	physical_block_number_t high4 = entry->pbn_high_nibble;
+
+	return (struct data_location) {
+		.pbn = ((high4 << 32) | low32),
+		.state = entry->mapping_state,
+	};
+}
+
+static inline bool vdo_is_mapped_location(const struct data_location *location)
+{
+	return (location->state != VDO_MAPPING_STATE_UNMAPPED);
+}
+
+static inline bool vdo_is_valid_location(const struct data_location *location)
+{
+	if (location->pbn == VDO_ZERO_BLOCK)
+		return !vdo_is_state_compressed(location->state);
+	else
+		return vdo_is_mapped_location(location);
+}
+
+static inline physical_block_number_t __must_check
+vdo_get_block_map_page_pbn(const struct block_map_page *page)
+{
+	return __le64_to_cpu(page->header.pbn);
+}
+
+struct block_map_page *vdo_format_block_map_page(void *buffer, nonce_t nonce,
+						 physical_block_number_t pbn,
+						 bool initialized);
+
+enum block_map_page_validity __must_check vdo_validate_block_map_page(struct block_map_page *page,
+								      nonce_t nonce,
+								      physical_block_number_t pbn);
+
+static inline page_count_t vdo_compute_block_map_page_count(block_count_t entries)
+{
+	return DIV_ROUND_UP(entries, VDO_BLOCK_MAP_ENTRIES_PER_PAGE);
+}
+
+block_count_t __must_check vdo_compute_new_forest_pages(root_count_t root_count,
+							struct boundary *old_sizes,
+							block_count_t entries,
+							struct boundary *new_sizes);
+
+/**
+ * vdo_pack_recovery_journal_entry() - Return the packed, on-disk representation of a recovery
+ *                                     journal entry.
+ * @entry: The journal entry to pack.
+ *
+ * Return: The packed representation of the journal entry.
+ */
+static inline struct packed_recovery_journal_entry
+vdo_pack_recovery_journal_entry(const struct recovery_journal_entry *entry)
+{
+	return (struct packed_recovery_journal_entry) {
+		.operation = entry->operation,
+		.slot_low = entry->slot.slot & 0x3F,
+		.slot_high = (entry->slot.slot >> 6) & 0x0F,
+		.pbn_high_nibble = (entry->slot.pbn >> 32) & 0x0F,
+		.pbn_low_word = __cpu_to_le32(entry->slot.pbn & UINT_MAX),
+		.mapping = vdo_pack_block_map_entry(entry->mapping.pbn,
+						    entry->mapping.state),
+		.unmapping = vdo_pack_block_map_entry(entry->unmapping.pbn,
+						      entry->unmapping.state),
+	};
+}
+
+/**
+ * vdo_unpack_recovery_journal_entry() - Unpack the on-disk representation of a recovery journal
+ *                                       entry.
+ * @entry: The recovery journal entry to unpack.
+ *
+ * Return: The unpacked entry.
+ */
+static inline struct recovery_journal_entry
+vdo_unpack_recovery_journal_entry(const struct packed_recovery_journal_entry *entry)
+{
+	physical_block_number_t low32 = __le32_to_cpu(entry->pbn_low_word);
+	physical_block_number_t high4 = entry->pbn_high_nibble;
+
+	return (struct recovery_journal_entry) {
+		.operation = entry->operation,
+		.slot = {
+			.pbn = ((high4 << 32) | low32),
+			.slot = (entry->slot_low | (entry->slot_high << 6)),
+		},
+		.mapping = vdo_unpack_block_map_entry(&entry->mapping),
+		.unmapping = vdo_unpack_block_map_entry(&entry->unmapping),
+	};
+}
+
+const char * __must_check vdo_get_journal_operation_name(enum journal_operation operation);
+
+/**
+ * vdo_is_valid_recovery_journal_sector() - Determine whether the header of the given sector could
+ *                                          describe a valid sector for the given journal block
+ *                                          header.
+ * @header: The unpacked block header to compare against.
+ * @sector: The packed sector to check.
+ * @sector_number: The number of the sector being checked.
+ *
+ * Return: true if the sector matches the block header.
+ */
+static inline bool __must_check
+vdo_is_valid_recovery_journal_sector(const struct recovery_block_header *header,
+				     const struct packed_journal_sector *sector,
+				     u8 sector_number)
+{
+	if ((header->check_byte != sector->check_byte) ||
+	    (header->recovery_count != sector->recovery_count))
+		return false;
+
+	if (header->metadata_type == VDO_METADATA_RECOVERY_JOURNAL_2)
+		return sector->entry_count <= RECOVERY_JOURNAL_ENTRIES_PER_SECTOR;
+
+	if (sector_number == 7)
+		return sector->entry_count <= RECOVERY_JOURNAL_1_ENTRIES_IN_LAST_SECTOR;
+
+	return sector->entry_count <= RECOVERY_JOURNAL_1_ENTRIES_PER_SECTOR;
+}
+
+/**
+ * vdo_compute_recovery_journal_block_number() - Compute the physical block number of the recovery
+ *                                               journal block which would have a given sequence
+ *                                               number.
+ * @journal_size: The size of the journal.
+ * @sequence_number: The sequence number.
+ *
+ * Return: The pbn of the journal block which would the specified sequence number.
+ */
+static inline physical_block_number_t __must_check
+vdo_compute_recovery_journal_block_number(block_count_t journal_size,
+					  sequence_number_t sequence_number)
+{
+	/*
+	 * Since journal size is a power of two, the block number modulus can just be extracted
+	 * from the low-order bits of the sequence.
+	 */
+	return (sequence_number & (journal_size - 1));
+}
+
+/**
+ * vdo_get_journal_block_sector() - Find the recovery journal sector from the block header and
+ *                                  sector number.
+ * @header: The header of the recovery journal block.
+ * @sector_number: The index of the sector (1-based).
+ *
+ * Return: A packed recovery journal sector.
+ */
+static inline struct packed_journal_sector * __must_check
+vdo_get_journal_block_sector(struct packed_journal_header *header, int sector_number)
+{
+	char *sector_data = ((char *) header) + (VDO_SECTOR_SIZE * sector_number);
+
+	return (struct packed_journal_sector *) sector_data;
+}
+
+/**
+ * vdo_pack_recovery_block_header() - Generate the packed representation of a recovery block
+ *                                    header.
+ * @header: The header containing the values to encode.
+ * @packed: The header into which to pack the values.
+ */
+static inline void vdo_pack_recovery_block_header(const struct recovery_block_header *header,
+						  struct packed_journal_header *packed)
+{
+	*packed = (struct packed_journal_header) {
+		.block_map_head = __cpu_to_le64(header->block_map_head),
+		.slab_journal_head = __cpu_to_le64(header->slab_journal_head),
+		.sequence_number = __cpu_to_le64(header->sequence_number),
+		.nonce = __cpu_to_le64(header->nonce),
+		.logical_blocks_used = __cpu_to_le64(header->logical_blocks_used),
+		.block_map_data_blocks = __cpu_to_le64(header->block_map_data_blocks),
+		.entry_count = __cpu_to_le16(header->entry_count),
+		.check_byte = header->check_byte,
+		.recovery_count = header->recovery_count,
+		.metadata_type = header->metadata_type,
+	};
+}
+
+/**
+ * vdo_unpack_recovery_block_header() - Decode the packed representation of a recovery block
+ *                                      header.
+ * @packed: The packed header to decode.
+ *
+ * Return: The unpacked header.
+ */
+static inline struct recovery_block_header
+vdo_unpack_recovery_block_header(const struct packed_journal_header *packed)
+{
+	return (struct recovery_block_header) {
+		.block_map_head = __le64_to_cpu(packed->block_map_head),
+		.slab_journal_head = __le64_to_cpu(packed->slab_journal_head),
+		.sequence_number = __le64_to_cpu(packed->sequence_number),
+		.nonce = __le64_to_cpu(packed->nonce),
+		.logical_blocks_used = __le64_to_cpu(packed->logical_blocks_used),
+		.block_map_data_blocks = __le64_to_cpu(packed->block_map_data_blocks),
+		.entry_count = __le16_to_cpu(packed->entry_count),
+		.check_byte = packed->check_byte,
+		.recovery_count = packed->recovery_count,
+		.metadata_type = packed->metadata_type,
+	};
+}
+
+/**
+ * vdo_compute_slab_count() - Compute the number of slabs a depot with given parameters would have.
+ * @first_block: PBN of the first data block.
+ * @last_block: PBN of the last data block.
+ * @slab_size_shift: Exponent for the number of blocks per slab.
+ *
+ * Return: The number of slabs.
+ */
+static inline slab_count_t vdo_compute_slab_count(physical_block_number_t first_block,
+						  physical_block_number_t last_block,
+						  unsigned int slab_size_shift)
+{
+	return (slab_count_t) ((last_block - first_block) >> slab_size_shift);
+}
+
+int __must_check vdo_configure_slab_depot(const struct partition *partition,
+					  struct slab_config slab_config,
+					  zone_count_t zone_count,
+					  struct slab_depot_state_2_0 *state);
+
+int __must_check vdo_configure_slab(block_count_t slab_size,
+				    block_count_t slab_journal_blocks,
+				    struct slab_config *slab_config);
+
+/**
+ * vdo_get_saved_reference_count_size() - Get the number of blocks required to save a reference
+ *                                        counts state covering the specified number of data
+ *                                        blocks.
+ * @block_count: The number of physical data blocks that can be referenced.
+ *
+ * Return: The number of blocks required to save reference counts with the given block count.
+ */
+static inline block_count_t vdo_get_saved_reference_count_size(block_count_t block_count)
+{
+	return DIV_ROUND_UP(block_count, COUNTS_PER_BLOCK);
+}
+
+/**
+ * vdo_get_slab_journal_start_block() - Get the physical block number of the start of the slab
+ *                                      journal relative to the start block allocator partition.
+ * @slab_config: The slab configuration of the VDO.
+ * @origin: The first block of the slab.
+ */
+static inline physical_block_number_t __must_check
+vdo_get_slab_journal_start_block(const struct slab_config *slab_config,
+				 physical_block_number_t origin)
+{
+	return origin + slab_config->data_blocks + slab_config->reference_count_blocks;
+}
+
+/**
+ * vdo_advance_journal_point() - Move the given journal point forward by one entry.
+ * @point: The journal point to adjust.
+ * @entries_per_block: The number of entries in one full block.
+ */
+static inline void vdo_advance_journal_point(struct journal_point *point,
+					     journal_entry_count_t entries_per_block)
+{
+	point->entry_count++;
+	if (point->entry_count == entries_per_block) {
+		point->sequence_number++;
+		point->entry_count = 0;
+	}
+}
+
+/**
+ * vdo_before_journal_point() - Check whether the first point precedes the second point.
+ * @first: The first journal point.
+ * @second: The second journal point.
+ *
+ * Return: true if the first point precedes the second point.
+ */
+static inline bool vdo_before_journal_point(const struct journal_point *first,
+					    const struct journal_point *second)
+{
+	return ((first->sequence_number < second->sequence_number) ||
+		((first->sequence_number == second->sequence_number) &&
+		 (first->entry_count < second->entry_count)));
+}
+
+/**
+ * vdo_pack_journal_point() - Encode the journal location represented by a
+ *                            journal_point into a packed_journal_point.
+ * @unpacked: The unpacked input point.
+ * @packed: The packed output point.
+ */
+static inline void vdo_pack_journal_point(const struct journal_point *unpacked,
+					  struct packed_journal_point *packed)
+{
+	packed->encoded_point =
+		__cpu_to_le64((unpacked->sequence_number << 16) | unpacked->entry_count);
+}
+
+/**
+ * vdo_unpack_journal_point() - Decode the journal location represented by a packed_journal_point
+ *                              into a journal_point.
+ * @packed: The packed input point.
+ * @unpacked: The unpacked output point.
+ */
+static inline void vdo_unpack_journal_point(const struct packed_journal_point *packed,
+					    struct journal_point *unpacked)
+{
+	u64 native = __le64_to_cpu(packed->encoded_point);
+
+	unpacked->sequence_number = (native >> 16);
+	unpacked->entry_count = (native & 0xffff);
+}
+
+/**
+ * vdo_pack_slab_journal_block_header() - Generate the packed representation of a slab block
+ *                                        header.
+ * @header: The header containing the values to encode.
+ * @packed: The header into which to pack the values.
+ */
+static inline void
+vdo_pack_slab_journal_block_header(const struct slab_journal_block_header *header,
+				   struct packed_slab_journal_block_header *packed)
+{
+	packed->head = __cpu_to_le64(header->head);
+	packed->sequence_number = __cpu_to_le64(header->sequence_number);
+	packed->nonce = __cpu_to_le64(header->nonce);
+	packed->entry_count = __cpu_to_le16(header->entry_count);
+	packed->metadata_type = header->metadata_type;
+	packed->has_block_map_increments = header->has_block_map_increments;
+
+	vdo_pack_journal_point(&header->recovery_point, &packed->recovery_point);
+}
+
+/**
+ * vdo_unpack_slab_journal_block_header() - Decode the packed representation of a slab block
+ *                                          header.
+ * @packed: The packed header to decode.
+ * @header: The header into which to unpack the values.
+ */
+static inline void
+vdo_unpack_slab_journal_block_header(const struct packed_slab_journal_block_header *packed,
+				     struct slab_journal_block_header *header)
+{
+	*header = (struct slab_journal_block_header) {
+		.head = __le64_to_cpu(packed->head),
+		.sequence_number = __le64_to_cpu(packed->sequence_number),
+		.nonce = __le64_to_cpu(packed->nonce),
+		.entry_count = __le16_to_cpu(packed->entry_count),
+		.metadata_type = packed->metadata_type,
+		.has_block_map_increments = packed->has_block_map_increments,
+	};
+	vdo_unpack_journal_point(&packed->recovery_point, &header->recovery_point);
+}
+
+/**
+ * vdo_pack_slab_journal_entry() - Generate the packed encoding of a slab journal entry.
+ * @packed: The entry into which to pack the values.
+ * @sbn: The slab block number of the entry to encode.
+ * @is_increment: The increment flag.
+ */
+static inline void vdo_pack_slab_journal_entry(packed_slab_journal_entry *packed,
+					       slab_block_number sbn, bool is_increment)
+{
+	packed->offset_low8 = (sbn & 0x0000FF);
+	packed->offset_mid8 = (sbn & 0x00FF00) >> 8;
+	packed->offset_high7 = (sbn & 0x7F0000) >> 16;
+	packed->increment = is_increment ? 1 : 0;
+}
+
+/**
+ * vdo_unpack_slab_journal_entry() - Decode the packed representation of a slab journal entry.
+ * @packed: The packed entry to decode.
+ *
+ * Return: The decoded slab journal entry.
+ */
+static inline struct slab_journal_entry __must_check
+vdo_unpack_slab_journal_entry(const packed_slab_journal_entry *packed)
+{
+	struct slab_journal_entry entry;
+
+	entry.sbn = packed->offset_high7;
+	entry.sbn <<= 8;
+	entry.sbn |= packed->offset_mid8;
+	entry.sbn <<= 8;
+	entry.sbn |= packed->offset_low8;
+	entry.operation = VDO_JOURNAL_DATA_REMAPPING;
+	entry.increment = packed->increment;
+	return entry;
+}
+
+struct slab_journal_entry __must_check
+vdo_decode_slab_journal_entry(struct packed_slab_journal_block *block,
+			      journal_entry_count_t entry_count);
+
+/**
+ * vdo_get_slab_summary_hint_shift() - Compute the shift for slab summary hints.
+ * @slab_size_shift: Exponent for the number of blocks per slab.
+ *
+ * Return: The hint shift.
+ */
+static inline u8 __must_check vdo_get_slab_summary_hint_shift(unsigned int slab_size_shift)
+{
+	return ((slab_size_shift > VDO_SLAB_SUMMARY_FULLNESS_HINT_BITS) ?
+		(slab_size_shift - VDO_SLAB_SUMMARY_FULLNESS_HINT_BITS) :
+		0);
+}
+
+int __must_check vdo_initialize_layout(block_count_t size,
+				       physical_block_number_t offset,
+				       block_count_t block_map_blocks,
+				       block_count_t journal_blocks,
+				       block_count_t summary_blocks,
+				       struct layout *layout);
+
+void vdo_uninitialize_layout(struct layout *layout);
+
+int __must_check vdo_get_partition(struct layout *layout, enum partition_id id,
+				   struct partition **partition_ptr);
+
+struct partition * __must_check vdo_get_known_partition(struct layout *layout,
+							enum partition_id id);
+
+int vdo_validate_config(const struct vdo_config *config,
+			block_count_t physical_block_count,
+			block_count_t logical_block_count);
+
+void vdo_destroy_component_states(struct vdo_component_states *states);
+
+int __must_check vdo_decode_component_states(u8 *buffer,
+					     struct volume_geometry *geometry,
+					     struct vdo_component_states *states);
+
+int __must_check vdo_validate_component_states(struct vdo_component_states *states,
+					       nonce_t geometry_nonce,
+					       block_count_t physical_size,
+					       block_count_t logical_size);
+
+void vdo_encode_super_block(u8 *buffer, struct vdo_component_states *states);
+int __must_check vdo_decode_super_block(u8 *buffer);
+
+/* We start with 0L and postcondition with ~0L to match our historical usage in userspace. */
+static inline u32 vdo_crc32(const void *buf, unsigned long len)
+{
+	return (crc32(0L, buf, len) ^ ~0L);
+}
+
+#endif /* VDO_ENCODINGS_H */