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Editing: 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 */
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