1 #ifndef _LINUX_BCACHE_H
2 #define _LINUX_BCACHE_H
5 * Bcache on disk data structures
10 #define BITMASK(name, type, field, offset, size) \
11 static inline __u64 name(const type *k) \
12 { return (k->field >> offset) & ~(~0ULL << size); } \
14 static inline void SET_##name(type *k, __u64 v) \
16 k->field &= ~(~(~0ULL << size) << offset); \
17 k->field |= (v & ~(~0ULL << size)) << offset; \
20 /* Btree keys - all units are in sectors */
28 #define KEY_FIELD(name, field, offset, size) \
29 BITMASK(name, struct bkey, field, offset, size)
31 #define PTR_FIELD(name, offset, size) \
32 static inline __u64 name(const struct bkey *k, unsigned i) \
33 { return (k->ptr[i] >> offset) & ~(~0ULL << size); } \
35 static inline void SET_##name(struct bkey *k, unsigned i, __u64 v) \
37 k->ptr[i] &= ~(~(~0ULL << size) << offset); \
38 k->ptr[i] |= (v & ~(~0ULL << size)) << offset; \
41 #define KEY_SIZE_BITS 16
43 KEY_FIELD(KEY_PTRS, high, 60, 3)
44 KEY_FIELD(HEADER_SIZE, high, 58, 2)
45 KEY_FIELD(KEY_CSUM, high, 56, 2)
46 KEY_FIELD(KEY_PINNED, high, 55, 1)
47 KEY_FIELD(KEY_DIRTY, high, 36, 1)
49 KEY_FIELD(KEY_SIZE, high, 20, KEY_SIZE_BITS)
50 KEY_FIELD(KEY_INODE, high, 0, 20)
52 /* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */
54 static inline __u64 KEY_OFFSET(const struct bkey *k)
59 static inline void SET_KEY_OFFSET(struct bkey *k, __u64 v)
65 * The high bit being set is a relic from when we used it to do binary
66 * searches - it told you where a key started. It's not used anymore,
67 * and can probably be safely dropped.
69 #define KEY(inode, offset, size) \
71 .high = (1ULL << 63) | ((__u64) (size) << 20) | (inode), \
75 #define ZERO_KEY KEY(0, 0, 0)
77 #define MAX_KEY_INODE (~(~0 << 20))
78 #define MAX_KEY_OFFSET (~0ULL >> 1)
79 #define MAX_KEY KEY(MAX_KEY_INODE, MAX_KEY_OFFSET, 0)
81 #define KEY_START(k) (KEY_OFFSET(k) - KEY_SIZE(k))
82 #define START_KEY(k) KEY(KEY_INODE(k), KEY_START(k), 0)
84 #define PTR_DEV_BITS 12
86 PTR_FIELD(PTR_DEV, 51, PTR_DEV_BITS)
87 PTR_FIELD(PTR_OFFSET, 8, 43)
88 PTR_FIELD(PTR_GEN, 0, 8)
90 #define PTR_CHECK_DEV ((1 << PTR_DEV_BITS) - 1)
92 #define PTR(gen, offset, dev) \
93 ((((__u64) dev) << 51) | ((__u64) offset) << 8 | gen)
95 /* Bkey utility code */
97 static inline unsigned long bkey_u64s(const struct bkey *k)
99 return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k);
102 static inline unsigned long bkey_bytes(const struct bkey *k)
104 return bkey_u64s(k) * sizeof(__u64);
107 #define bkey_copy(_dest, _src) memcpy(_dest, _src, bkey_bytes(_src))
109 static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src)
111 SET_KEY_INODE(dest, KEY_INODE(src));
112 SET_KEY_OFFSET(dest, KEY_OFFSET(src));
115 static inline struct bkey *bkey_next(const struct bkey *k)
117 __u64 *d = (void *) k;
118 return (struct bkey *) (d + bkey_u64s(k));
121 static inline struct bkey *bkey_last(const struct bkey *k, unsigned nr_keys)
123 __u64 *d = (void *) k;
124 return (struct bkey *) (d + nr_keys);
126 /* Enough for a key with 6 pointers */
129 #define BKEY_PADDED(key) \
130 union { struct bkey key; __u64 key ## _pad[BKEY_PAD]; }
134 /* Version 0: Cache device
135 * Version 1: Backing device
136 * Version 2: Seed pointer into btree node checksum
137 * Version 3: Cache device with new UUID format
138 * Version 4: Backing device with data offset
140 #define BCACHE_SB_VERSION_CDEV 0
141 #define BCACHE_SB_VERSION_BDEV 1
142 #define BCACHE_SB_VERSION_CDEV_WITH_UUID 3
143 #define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4
144 #define BCACHE_SB_MAX_VERSION 4
148 #define SB_LABEL_SIZE 32
149 #define SB_JOURNAL_BUCKETS 256U
150 /* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */
151 #define MAX_CACHES_PER_SET 8
153 #define BDEV_DATA_START_DEFAULT 16 /* sectors */
157 __u64 offset; /* sector where this sb was written */
167 __u8 label[SB_LABEL_SIZE];
176 __u64 nbuckets; /* device size */
178 __u16 block_size; /* sectors */
179 __u16 bucket_size; /* sectors */
185 /* Backing devices */
189 * block_size from the cache device section is still used by
190 * backing devices, so don't add anything here until we fix
191 * things to not need it for backing devices anymore
196 __u32 last_mount; /* time_t */
200 __u16 njournal_buckets;
203 __u64 d[SB_JOURNAL_BUCKETS]; /* journal buckets */
206 static inline _Bool SB_IS_BDEV(const struct cache_sb *sb)
208 return sb->version == BCACHE_SB_VERSION_BDEV
209 || sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET;
212 BITMASK(CACHE_SYNC, struct cache_sb, flags, 0, 1);
213 BITMASK(CACHE_DISCARD, struct cache_sb, flags, 1, 1);
214 BITMASK(CACHE_REPLACEMENT, struct cache_sb, flags, 2, 3);
215 #define CACHE_REPLACEMENT_LRU 0U
216 #define CACHE_REPLACEMENT_FIFO 1U
217 #define CACHE_REPLACEMENT_RANDOM 2U
219 BITMASK(BDEV_CACHE_MODE, struct cache_sb, flags, 0, 4);
220 #define CACHE_MODE_WRITETHROUGH 0U
221 #define CACHE_MODE_WRITEBACK 1U
222 #define CACHE_MODE_WRITEAROUND 2U
223 #define CACHE_MODE_NONE 3U
224 BITMASK(BDEV_STATE, struct cache_sb, flags, 61, 2);
225 #define BDEV_STATE_NONE 0U
226 #define BDEV_STATE_CLEAN 1U
227 #define BDEV_STATE_DIRTY 2U
228 #define BDEV_STATE_STALE 3U
233 * The various other data structures have their own magic numbers, which are
234 * xored with the first part of the cache set's UUID
237 #define JSET_MAGIC 0x245235c1a3625032ULL
238 #define PSET_MAGIC 0x6750e15f87337f91ULL
239 #define BSET_MAGIC 0x90135c78b99e07f5ULL
241 static inline __u64 jset_magic(struct cache_sb *sb)
243 return sb->set_magic ^ JSET_MAGIC;
246 static inline __u64 pset_magic(struct cache_sb *sb)
248 return sb->set_magic ^ PSET_MAGIC;
251 static inline __u64 bset_magic(struct cache_sb *sb)
253 return sb->set_magic ^ BSET_MAGIC;
259 * On disk format for a journal entry:
260 * seq is monotonically increasing; every journal entry has its own unique
263 * last_seq is the oldest journal entry that still has keys the btree hasn't
264 * flushed to disk yet.
266 * version is for on disk format changes.
269 #define BCACHE_JSET_VERSION_UUIDv1 1
270 #define BCACHE_JSET_VERSION_UUID 1 /* Always latest UUID format */
271 #define BCACHE_JSET_VERSION 1
282 BKEY_PADDED(uuid_bucket);
283 BKEY_PADDED(btree_root);
287 __u64 prio_bucket[MAX_CACHES_PER_SET];
290 struct bkey start[0];
295 /* Bucket prios/gens */
309 } __attribute((packed)) data[];
312 /* UUIDS - per backing device/flash only volume metadata */
324 /* Size of flash only volumes */
332 BITMASK(UUID_FLASH_ONLY, struct uuid_entry, flags, 0, 1);
336 /* Version 1: Seed pointer into btree node checksum
338 #define BCACHE_BSET_CSUM 1
339 #define BCACHE_BSET_VERSION 1
344 * On disk a btree node is a list/log of these; within each set the keys are
355 struct bkey start[0];
362 /* UUIDS - per backing device/flash only volume metadata */
364 struct uuid_entry_v0 {
373 #endif /* _LINUX_BCACHE_H */