diff options
Diffstat (limited to 'include/uapi/linux/bcache.h')
| -rw-r--r-- | include/uapi/linux/bcache.h | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/include/uapi/linux/bcache.h b/include/uapi/linux/bcache.h new file mode 100644 index 00000000000..164a7e26398 --- /dev/null +++ b/include/uapi/linux/bcache.h @@ -0,0 +1,373 @@ +#ifndef _LINUX_BCACHE_H +#define _LINUX_BCACHE_H + +/* + * Bcache on disk data structures + */ + +#include <asm/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 + +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 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_last(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 */ |