include/uapi/linux/bcache.h - kernel/common - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 #ifndef _LINUX_BCACHE_H
 #define _LINUX_BCACHE_H

 /*
  * Bcache on disk data structures
  */

 #include <linux/types.h>

 #define BITMASK(name, type, field, offset, size)		\
 static inline __u64 name(const type *k)				\
 { return (k->field >> offset) & ~(~0ULL << size); }		\
 								\
 static inline void SET_##name(type *k, __u64 v)			\
 {								\
 	k->field &= ~(~(~0ULL << size) << offset);		\
 	k->field |= (v & ~(~0ULL << size)) << offset;		\
 }

 /* Btree keys - all units are in sectors */

 struct bkey {
 	__u64	high;
 	__u64	low;
 	__u64	ptr[];
 };

 #define KEY_FIELD(name, field, offset, size)				\
 	BITMASK(name, struct bkey, field, offset, size)

 #define PTR_FIELD(name, offset, size)					\
 static inline __u64 name(const struct bkey *k, unsigned i)		\
 { return (k->ptr[i] >> offset) & ~(~0ULL << size); }			\
 									\
 static inline void SET_##name(struct bkey *k, unsigned i, __u64 v)	\
 {									\
 	k->ptr[i] &= ~(~(~0ULL << size) << offset);			\
 	k->ptr[i] |= (v & ~(~0ULL << size)) << offset;			\
 }

 #define KEY_SIZE_BITS		16
 #define KEY_MAX_U64S		8

 KEY_FIELD(KEY_PTRS,	high, 60, 3)
 KEY_FIELD(HEADER_SIZE,	high, 58, 2)
 KEY_FIELD(KEY_CSUM,	high, 56, 2)
 KEY_FIELD(KEY_PINNED,	high, 55, 1)
 KEY_FIELD(KEY_DIRTY,	high, 36, 1)

 KEY_FIELD(KEY_SIZE,	high, 20, KEY_SIZE_BITS)
 KEY_FIELD(KEY_INODE,	high, 0,  20)

 /* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */

 static inline __u64 KEY_OFFSET(const struct bkey *k)
 {
 	return k->low;
 }

 static inline void SET_KEY_OFFSET(struct bkey *k, __u64 v)
 {
 	k->low = v;
 }

 /*
  * The high bit being set is a relic from when we used it to do binary
  * searches - it told you where a key started. It's not used anymore,
  * and can probably be safely dropped.
  */
 #define KEY(inode, offset, size)					\
 ((struct bkey) {							\
 	.high = (1ULL << 63) | ((__u64) (size) << 20) | (inode),	\
 	.low = (offset)							\
 })

 #define ZERO_KEY			KEY(0, 0, 0)

 #define MAX_KEY_INODE			(~(~0 << 20))
 #define MAX_KEY_OFFSET			(~0ULL >> 1)
 #define MAX_KEY				KEY(MAX_KEY_INODE, MAX_KEY_OFFSET, 0)

 #define KEY_START(k)			(KEY_OFFSET(k) - KEY_SIZE(k))
 #define START_KEY(k)			KEY(KEY_INODE(k), KEY_START(k), 0)

 #define PTR_DEV_BITS			12

 PTR_FIELD(PTR_DEV,			51, PTR_DEV_BITS)
 PTR_FIELD(PTR_OFFSET,			8,  43)
 PTR_FIELD(PTR_GEN,			0,  8)

 #define PTR_CHECK_DEV			((1 << PTR_DEV_BITS) - 1)

 #define MAKE_PTR(gen, offset, dev)					\
 	((((__u64) dev) << 51) | ((__u64) offset) << 8 | gen)

 /* Bkey utility code */

 static inline unsigned long bkey_u64s(const struct bkey *k)
 {
 	return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k);
 }

 static inline unsigned long bkey_bytes(const struct bkey *k)
 {
 	return bkey_u64s(k) * sizeof(__u64);
 }

 #define bkey_copy(_dest, _src)	memcpy(_dest, _src, bkey_bytes(_src))

 static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src)
 {
 	SET_KEY_INODE(dest, KEY_INODE(src));
 	SET_KEY_OFFSET(dest, KEY_OFFSET(src));
 }

 static inline struct bkey *bkey_next(const struct bkey *k)
 {
 	__u64 *d = (void *) k;
 	return (struct bkey *) (d + bkey_u64s(k));
 }

 static inline struct bkey *bkey_idx(const struct bkey *k, unsigned nr_keys)
 {
 	__u64 *d = (void *) k;
 	return (struct bkey *) (d + nr_keys);
 }
 /* Enough for a key with 6 pointers */
 #define BKEY_PAD		8

 #define BKEY_PADDED(key)					\
 	union { struct bkey key; __u64 key ## _pad[BKEY_PAD]; }

 /* Superblock */

 /* Version 0: Cache device
  * Version 1: Backing device
  * Version 2: Seed pointer into btree node checksum
  * Version 3: Cache device with new UUID format
  * Version 4: Backing device with data offset
  */
 #define BCACHE_SB_VERSION_CDEV		0
 #define BCACHE_SB_VERSION_BDEV		1
 #define BCACHE_SB_VERSION_CDEV_WITH_UUID 3
 #define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4
 #define BCACHE_SB_MAX_VERSION		4

 #define SB_SECTOR			8
 #define SB_SIZE				4096
 #define SB_LABEL_SIZE			32
 #define SB_JOURNAL_BUCKETS		256U
 /* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */
 #define MAX_CACHES_PER_SET		8

 #define BDEV_DATA_START_DEFAULT		16	/* sectors */

 struct cache_sb {
 	__u64			csum;
 	__u64			offset;	/* sector where this sb was written */
 	__u64			version;

 	__u8			magic[16];

 	__u8			uuid[16];
 	union {
 		__u8		set_uuid[16];
 		__u64		set_magic;
 	};
 	__u8			label[SB_LABEL_SIZE];

 	__u64			flags;
 	__u64			seq;
 	__u64			pad[8];

 	union {
 	struct {
 		/* Cache devices */
 		__u64		nbuckets;	/* device size */

 		__u16		block_size;	/* sectors */
 		__u16		bucket_size;	/* sectors */

 		__u16		nr_in_set;
 		__u16		nr_this_dev;
 	};
 	struct {
 		/* Backing devices */
 		__u64		data_offset;

 		/*
 		 * block_size from the cache device section is still used by
 		 * backing devices, so don't add anything here until we fix
 		 * things to not need it for backing devices anymore
 		 */
 	};
 	};

 	__u32			last_mount;	/* time_t */

 	__u16			first_bucket;
 	union {
 		__u16		njournal_buckets;
 		__u16		keys;
 	};
 	__u64			d[SB_JOURNAL_BUCKETS];	/* journal buckets */
 };

 static inline _Bool SB_IS_BDEV(const struct cache_sb *sb)
 {
 	return sb->version == BCACHE_SB_VERSION_BDEV
 		|| sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET;
 }

 BITMASK(CACHE_SYNC,			struct cache_sb, flags, 0, 1);
 BITMASK(CACHE_DISCARD,			struct cache_sb, flags, 1, 1);
 BITMASK(CACHE_REPLACEMENT,		struct cache_sb, flags, 2, 3);
 #define CACHE_REPLACEMENT_LRU		0U
 #define CACHE_REPLACEMENT_FIFO		1U
 #define CACHE_REPLACEMENT_RANDOM	2U

 BITMASK(BDEV_CACHE_MODE,		struct cache_sb, flags, 0, 4);
 #define CACHE_MODE_WRITETHROUGH		0U
 #define CACHE_MODE_WRITEBACK		1U
 #define CACHE_MODE_WRITEAROUND		2U
 #define CACHE_MODE_NONE			3U
 BITMASK(BDEV_STATE,			struct cache_sb, flags, 61, 2);
 #define BDEV_STATE_NONE			0U
 #define BDEV_STATE_CLEAN		1U
 #define BDEV_STATE_DIRTY		2U
 #define BDEV_STATE_STALE		3U

 /*
  * Magic numbers
  *
  * The various other data structures have their own magic numbers, which are
  * xored with the first part of the cache set's UUID
  */

 #define JSET_MAGIC			0x245235c1a3625032ULL
 #define PSET_MAGIC			0x6750e15f87337f91ULL
 #define BSET_MAGIC			0x90135c78b99e07f5ULL

 static inline __u64 jset_magic(struct cache_sb *sb)
 {
 	return sb->set_magic ^ JSET_MAGIC;
 }

 static inline __u64 pset_magic(struct cache_sb *sb)
 {
 	return sb->set_magic ^ PSET_MAGIC;
 }

 static inline __u64 bset_magic(struct cache_sb *sb)
 {
 	return sb->set_magic ^ BSET_MAGIC;
 }

 /*
  * Journal
  *
  * On disk format for a journal entry:
  * seq is monotonically increasing; every journal entry has its own unique
  * sequence number.
  *
  * last_seq is the oldest journal entry that still has keys the btree hasn't
  * flushed to disk yet.
  *
  * version is for on disk format changes.
  */

 #define BCACHE_JSET_VERSION_UUIDv1	1
 #define BCACHE_JSET_VERSION_UUID	1	/* Always latest UUID format */
 #define BCACHE_JSET_VERSION		1

 struct jset {
 	__u64			csum;
 	__u64			magic;
 	__u64			seq;
 	__u32			version;
 	__u32			keys;

 	__u64			last_seq;

 	BKEY_PADDED(uuid_bucket);
 	BKEY_PADDED(btree_root);
 	__u16			btree_level;
 	__u16			pad[3];

 	__u64			prio_bucket[MAX_CACHES_PER_SET];

 	union {
 		struct bkey	start[0];
 		__u64		d[0];
 	};
 };

 /* Bucket prios/gens */

 struct prio_set {
 	__u64			csum;
 	__u64			magic;
 	__u64			seq;
 	__u32			version;
 	__u32			pad;

 	__u64			next_bucket;

 	struct bucket_disk {
 		__u16		prio;
 		__u8		gen;
 	} __attribute((packed)) data[];
 };

 /* UUIDS - per backing device/flash only volume metadata */

 struct uuid_entry {
 	union {
 		struct {
 			__u8	uuid[16];
 			__u8	label[32];
 			__u32	first_reg;
 			__u32	last_reg;
 			__u32	invalidated;

 			__u32	flags;
 			/* Size of flash only volumes */
 			__u64	sectors;
 		};

 		__u8		pad[128];
 	};
 };

 BITMASK(UUID_FLASH_ONLY,	struct uuid_entry, flags, 0, 1);

 /* Btree nodes */

 /* Version 1: Seed pointer into btree node checksum
  */
 #define BCACHE_BSET_CSUM		1
 #define BCACHE_BSET_VERSION		1

 /*
  * Btree nodes
  *
  * On disk a btree node is a list/log of these; within each set the keys are
  * sorted
  */
 struct bset {
 	__u64			csum;
 	__u64			magic;
 	__u64			seq;
 	__u32			version;
 	__u32			keys;

 	union {
 		struct bkey	start[0];
 		__u64		d[0];
 	};
 };

 /* OBSOLETE */

 /* UUIDS - per backing device/flash only volume metadata */

 struct uuid_entry_v0 {
 	__u8		uuid[16];
 	__u8		label[32];
 	__u32		first_reg;
 	__u32		last_reg;
 	__u32		invalidated;
 	__u32		pad;
 };

 #endif /* _LINUX_BCACHE_H */
	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
	#ifndef _LINUX_BCACHE_H
	#define _LINUX_BCACHE_H

	/*
	* Bcache on disk data structures
	*/

	#include <linux/types.h>

	#define BITMASK(name, type, field, offset, size) \
	static inline __u64 name(const type *k) \
	{ return (k->field >> offset) & ~(~0ULL << size); } \
	\
	static inline void SET_##name(type *k, __u64 v) \
	{ \
	k->field &= ~(~(~0ULL << size) << offset); \
	k->field \|= (v & ~(~0ULL << size)) << offset; \
	}

	/* Btree keys - all units are in sectors */

	struct bkey {
	__u64 high;
	__u64 low;
	__u64 ptr[];
	};

	#define KEY_FIELD(name, field, offset, size) \
	BITMASK(name, struct bkey, field, offset, size)

	#define PTR_FIELD(name, offset, size) \
	static inline __u64 name(const struct bkey *k, unsigned i) \
	{ return (k->ptr[i] >> offset) & ~(~0ULL << size); } \
	\
	static inline void SET_##name(struct bkey *k, unsigned i, __u64 v) \
	{ \
	k->ptr[i] &= ~(~(~0ULL << size) << offset); \
	k->ptr[i] \|= (v & ~(~0ULL << size)) << offset; \
	}

	#define KEY_SIZE_BITS 16
	#define KEY_MAX_U64S 8

	KEY_FIELD(KEY_PTRS, high, 60, 3)
	KEY_FIELD(HEADER_SIZE, high, 58, 2)
	KEY_FIELD(KEY_CSUM, high, 56, 2)
	KEY_FIELD(KEY_PINNED, high, 55, 1)
	KEY_FIELD(KEY_DIRTY, high, 36, 1)

	KEY_FIELD(KEY_SIZE, high, 20, KEY_SIZE_BITS)
	KEY_FIELD(KEY_INODE, high, 0, 20)

	/* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */

	static inline __u64 KEY_OFFSET(const struct bkey *k)
	{
	return k->low;
	}

	static inline void SET_KEY_OFFSET(struct bkey *k, __u64 v)
	{
	k->low = v;
	}

	/*
	* The high bit being set is a relic from when we used it to do binary
	* searches - it told you where a key started. It's not used anymore,
	* and can probably be safely dropped.
	*/
	#define KEY(inode, offset, size) \
	((struct bkey) { \
	.high = (1ULL << 63) \| ((__u64) (size) << 20) \| (inode), \
	.low = (offset) \
	})

	#define ZERO_KEY KEY(0, 0, 0)

	#define MAX_KEY_INODE (~(~0 << 20))
	#define MAX_KEY_OFFSET (~0ULL >> 1)
	#define MAX_KEY KEY(MAX_KEY_INODE, MAX_KEY_OFFSET, 0)

	#define KEY_START(k) (KEY_OFFSET(k) - KEY_SIZE(k))
	#define START_KEY(k) KEY(KEY_INODE(k), KEY_START(k), 0)

	#define PTR_DEV_BITS 12

	PTR_FIELD(PTR_DEV, 51, PTR_DEV_BITS)
	PTR_FIELD(PTR_OFFSET, 8, 43)
	PTR_FIELD(PTR_GEN, 0, 8)

	#define PTR_CHECK_DEV ((1 << PTR_DEV_BITS) - 1)

	#define MAKE_PTR(gen, offset, dev) \
	((((__u64) dev) << 51) \| ((__u64) offset) << 8 \| gen)

	/* Bkey utility code */

	static inline unsigned long bkey_u64s(const struct bkey *k)
	{
	return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k);
	}

	static inline unsigned long bkey_bytes(const struct bkey *k)
	{
	return bkey_u64s(k) * sizeof(__u64);
	}

	#define bkey_copy(_dest, _src) memcpy(_dest, _src, bkey_bytes(_src))

	static inline void bkey_copy_key(struct bkey dest, const struct bkey src)
	{
	SET_KEY_INODE(dest, KEY_INODE(src));
	SET_KEY_OFFSET(dest, KEY_OFFSET(src));
	}

	static inline struct bkey bkey_next(const struct bkey k)
	{
	__u64 d = (void ) k;
	return (struct bkey *) (d + bkey_u64s(k));
	}

	static inline struct bkey bkey_idx(const struct bkey k, unsigned nr_keys)
	{
	__u64 d = (void ) k;
	return (struct bkey *) (d + nr_keys);
	}
	/* Enough for a key with 6 pointers */
	#define BKEY_PAD 8

	#define BKEY_PADDED(key) \
	union { struct bkey key; __u64 key ## _pad[BKEY_PAD]; }

	/* Superblock */

	/* Version 0: Cache device
	* Version 1: Backing device
	* Version 2: Seed pointer into btree node checksum
	* Version 3: Cache device with new UUID format
	* Version 4: Backing device with data offset
	*/
	#define BCACHE_SB_VERSION_CDEV 0
	#define BCACHE_SB_VERSION_BDEV 1
	#define BCACHE_SB_VERSION_CDEV_WITH_UUID 3
	#define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4
	#define BCACHE_SB_MAX_VERSION 4

	#define SB_SECTOR 8
	#define SB_SIZE 4096
	#define SB_LABEL_SIZE 32
	#define SB_JOURNAL_BUCKETS 256U
	/* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */
	#define MAX_CACHES_PER_SET 8

	#define BDEV_DATA_START_DEFAULT 16 /* sectors */

	struct cache_sb {
	__u64 csum;
	__u64 offset; /* sector where this sb was written */
	__u64 version;

	__u8 magic[16];

	__u8 uuid[16];
	union {
	__u8 set_uuid[16];
	__u64 set_magic;
	};
	__u8 label[SB_LABEL_SIZE];

	__u64 flags;
	__u64 seq;
	__u64 pad[8];

	union {
	struct {
	/* Cache devices */
	__u64 nbuckets; /* device size */

	__u16 block_size; /* sectors */
	__u16 bucket_size; /* sectors */

	__u16 nr_in_set;
	__u16 nr_this_dev;
	};
	struct {
	/* Backing devices */
	__u64 data_offset;

	/*
	* block_size from the cache device section is still used by
	* backing devices, so don't add anything here until we fix
	* things to not need it for backing devices anymore
	*/
	};
	};

	__u32 last_mount; /* time_t */

	__u16 first_bucket;
	union {
	__u16 njournal_buckets;
	__u16 keys;
	};
	__u64 d[SB_JOURNAL_BUCKETS]; /* journal buckets */
	};

	static inline _Bool SB_IS_BDEV(const struct cache_sb *sb)
	{
	return sb->version == BCACHE_SB_VERSION_BDEV
	\|\| sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET;
	}

	BITMASK(CACHE_SYNC, struct cache_sb, flags, 0, 1);
	BITMASK(CACHE_DISCARD, struct cache_sb, flags, 1, 1);
	BITMASK(CACHE_REPLACEMENT, struct cache_sb, flags, 2, 3);
	#define CACHE_REPLACEMENT_LRU 0U
	#define CACHE_REPLACEMENT_FIFO 1U
	#define CACHE_REPLACEMENT_RANDOM 2U

	BITMASK(BDEV_CACHE_MODE, struct cache_sb, flags, 0, 4);
	#define CACHE_MODE_WRITETHROUGH 0U
	#define CACHE_MODE_WRITEBACK 1U
	#define CACHE_MODE_WRITEAROUND 2U
	#define CACHE_MODE_NONE 3U
	BITMASK(BDEV_STATE, struct cache_sb, flags, 61, 2);
	#define BDEV_STATE_NONE 0U
	#define BDEV_STATE_CLEAN 1U
	#define BDEV_STATE_DIRTY 2U
	#define BDEV_STATE_STALE 3U

	/*
	* Magic numbers
	*
	* The various other data structures have their own magic numbers, which are
	* xored with the first part of the cache set's UUID
	*/

	#define JSET_MAGIC 0x245235c1a3625032ULL
	#define PSET_MAGIC 0x6750e15f87337f91ULL
	#define BSET_MAGIC 0x90135c78b99e07f5ULL

	static inline __u64 jset_magic(struct cache_sb *sb)
	{
	return sb->set_magic ^ JSET_MAGIC;
	}

	static inline __u64 pset_magic(struct cache_sb *sb)
	{
	return sb->set_magic ^ PSET_MAGIC;
	}

	static inline __u64 bset_magic(struct cache_sb *sb)
	{
	return sb->set_magic ^ BSET_MAGIC;
	}

	/*
	* Journal
	*
	* On disk format for a journal entry:
	* seq is monotonically increasing; every journal entry has its own unique
	* sequence number.
	*
	* last_seq is the oldest journal entry that still has keys the btree hasn't
	* flushed to disk yet.
	*
	* version is for on disk format changes.
	*/

	#define BCACHE_JSET_VERSION_UUIDv1 1
	#define BCACHE_JSET_VERSION_UUID 1 /* Always latest UUID format */
	#define BCACHE_JSET_VERSION 1

	struct jset {
	__u64 csum;
	__u64 magic;
	__u64 seq;
	__u32 version;
	__u32 keys;

	__u64 last_seq;

	BKEY_PADDED(uuid_bucket);
	BKEY_PADDED(btree_root);
	__u16 btree_level;
	__u16 pad[3];

	__u64 prio_bucket[MAX_CACHES_PER_SET];

	union {
	struct bkey start[0];
	__u64 d[0];
	};
	};

	/* Bucket prios/gens */

	struct prio_set {
	__u64 csum;
	__u64 magic;
	__u64 seq;
	__u32 version;
	__u32 pad;

	__u64 next_bucket;

	struct bucket_disk {
	__u16 prio;
	__u8 gen;
	} __attribute((packed)) data[];
	};

	/* UUIDS - per backing device/flash only volume metadata */

	struct uuid_entry {
	union {
	struct {
	__u8 uuid[16];
	__u8 label[32];
	__u32 first_reg;
	__u32 last_reg;
	__u32 invalidated;

	__u32 flags;
	/* Size of flash only volumes */
	__u64 sectors;
	};

	__u8 pad[128];
	};
	};

	BITMASK(UUID_FLASH_ONLY, struct uuid_entry, flags, 0, 1);

	/* Btree nodes */

	/* Version 1: Seed pointer into btree node checksum
	*/
	#define BCACHE_BSET_CSUM 1
	#define BCACHE_BSET_VERSION 1

	/*
	* Btree nodes
	*
	* On disk a btree node is a list/log of these; within each set the keys are
	* sorted
	*/
	struct bset {
	__u64 csum;
	__u64 magic;
	__u64 seq;
	__u32 version;
	__u32 keys;

	union {
	struct bkey start[0];
	__u64 d[0];
	};
	};

	/* OBSOLETE */

	/* UUIDS - per backing device/flash only volume metadata */

	struct uuid_entry_v0 {
	__u8 uuid[16];
	__u8 label[32];
	__u32 first_reg;
	__u32 last_reg;
	__u32 invalidated;
	__u32 pad;
	};

	#endif /* _LINUX_BCACHE_H */