1 #ifndef _LINUX_BCACHE_H 2 #define _LINUX_BCACHE_H 3 4 /* 5 * Bcache on disk data structures 6 */ 7 8 #include <asm/types.h> 9 10 #define BITMASK(name, type, field, offset, size) \ 11 static inline __u64 name(const type *k) \ 12 { return (k->field >> offset) & ~(~0ULL << size); } \ 13 \ 14 static inline void SET_##name(type *k, __u64 v) \ 15 { \ 16 k->field &= ~(~(~0ULL << size) << offset); \ 17 k->field |= (v & ~(~0ULL << size)) << offset; \ 18 } 19 20 /* Btree keys - all units are in sectors */ 21 22 struct bkey { 23 __u64 high; 24 __u64 low; 25 __u64 ptr[]; 26 }; 27 28 #define KEY_FIELD(name, field, offset, size) \ 29 BITMASK(name, struct bkey, field, offset, size) 30 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); } \ 34 \ 35 static inline void SET_##name(struct bkey *k, unsigned i, __u64 v) \ 36 { \ 37 k->ptr[i] &= ~(~(~0ULL << size) << offset); \ 38 k->ptr[i] |= (v & ~(~0ULL << size)) << offset; \ 39 } 40 41 #define KEY_SIZE_BITS 16 42 #define KEY_MAX_U64S 8 43 44 KEY_FIELD(KEY_PTRS, high, 60, 3) 45 KEY_FIELD(HEADER_SIZE, high, 58, 2) 46 KEY_FIELD(KEY_CSUM, high, 56, 2) 47 KEY_FIELD(KEY_PINNED, high, 55, 1) 48 KEY_FIELD(KEY_DIRTY, high, 36, 1) 49 50 KEY_FIELD(KEY_SIZE, high, 20, KEY_SIZE_BITS) 51 KEY_FIELD(KEY_INODE, high, 0, 20) 52 53 /* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */ 54 55 static inline __u64 KEY_OFFSET(const struct bkey *k) 56 { 57 return k->low; 58 } 59 60 static inline void SET_KEY_OFFSET(struct bkey *k, __u64 v) 61 { 62 k->low = v; 63 } 64 65 /* 66 * The high bit being set is a relic from when we used it to do binary 67 * searches - it told you where a key started. It's not used anymore, 68 * and can probably be safely dropped. 69 */ 70 #define KEY(inode, offset, size) \ 71 ((struct bkey) { \ 72 .high = (1ULL << 63) | ((__u64) (size) << 20) | (inode), \ 73 .low = (offset) \ 74 }) 75 76 #define ZERO_KEY KEY(0, 0, 0) 77 78 #define MAX_KEY_INODE (~(~0 << 20)) 79 #define MAX_KEY_OFFSET (~0ULL >> 1) 80 #define MAX_KEY KEY(MAX_KEY_INODE, MAX_KEY_OFFSET, 0) 81 82 #define KEY_START(k) (KEY_OFFSET(k) - KEY_SIZE(k)) 83 #define START_KEY(k) KEY(KEY_INODE(k), KEY_START(k), 0) 84 85 #define PTR_DEV_BITS 12 86 87 PTR_FIELD(PTR_DEV, 51, PTR_DEV_BITS) 88 PTR_FIELD(PTR_OFFSET, 8, 43) 89 PTR_FIELD(PTR_GEN, 0, 8) 90 91 #define PTR_CHECK_DEV ((1 << PTR_DEV_BITS) - 1) 92 93 #define PTR(gen, offset, dev) \ 94 ((((__u64) dev) << 51) | ((__u64) offset) << 8 | gen) 95 96 /* Bkey utility code */ 97 98 static inline unsigned long bkey_u64s(const struct bkey *k) 99 { 100 return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k); 101 } 102 103 static inline unsigned long bkey_bytes(const struct bkey *k) 104 { 105 return bkey_u64s(k) * sizeof(__u64); 106 } 107 108 #define bkey_copy(_dest, _src) memcpy(_dest, _src, bkey_bytes(_src)) 109 110 static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src) 111 { 112 SET_KEY_INODE(dest, KEY_INODE(src)); 113 SET_KEY_OFFSET(dest, KEY_OFFSET(src)); 114 } 115 116 static inline struct bkey *bkey_next(const struct bkey *k) 117 { 118 __u64 *d = (void *) k; 119 return (struct bkey *) (d + bkey_u64s(k)); 120 } 121 122 static inline struct bkey *bkey_idx(const struct bkey *k, unsigned nr_keys) 123 { 124 __u64 *d = (void *) k; 125 return (struct bkey *) (d + nr_keys); 126 } 127 /* Enough for a key with 6 pointers */ 128 #define BKEY_PAD 8 129 130 #define BKEY_PADDED(key) \ 131 union { struct bkey key; __u64 key ## _pad[BKEY_PAD]; } 132 133 /* Superblock */ 134 135 /* Version 0: Cache device 136 * Version 1: Backing device 137 * Version 2: Seed pointer into btree node checksum 138 * Version 3: Cache device with new UUID format 139 * Version 4: Backing device with data offset 140 */ 141 #define BCACHE_SB_VERSION_CDEV 0 142 #define BCACHE_SB_VERSION_BDEV 1 143 #define BCACHE_SB_VERSION_CDEV_WITH_UUID 3 144 #define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4 145 #define BCACHE_SB_MAX_VERSION 4 146 147 #define SB_SECTOR 8 148 #define SB_SIZE 4096 149 #define SB_LABEL_SIZE 32 150 #define SB_JOURNAL_BUCKETS 256U 151 /* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */ 152 #define MAX_CACHES_PER_SET 8 153 154 #define BDEV_DATA_START_DEFAULT 16 /* sectors */ 155 156 struct cache_sb { 157 __u64 csum; 158 __u64 offset; /* sector where this sb was written */ 159 __u64 version; 160 161 __u8 magic[16]; 162 163 __u8 uuid[16]; 164 union { 165 __u8 set_uuid[16]; 166 __u64 set_magic; 167 }; 168 __u8 label[SB_LABEL_SIZE]; 169 170 __u64 flags; 171 __u64 seq; 172 __u64 pad[8]; 173 174 union { 175 struct { 176 /* Cache devices */ 177 __u64 nbuckets; /* device size */ 178 179 __u16 block_size; /* sectors */ 180 __u16 bucket_size; /* sectors */ 181 182 __u16 nr_in_set; 183 __u16 nr_this_dev; 184 }; 185 struct { 186 /* Backing devices */ 187 __u64 data_offset; 188 189 /* 190 * block_size from the cache device section is still used by 191 * backing devices, so don't add anything here until we fix 192 * things to not need it for backing devices anymore 193 */ 194 }; 195 }; 196 197 __u32 last_mount; /* time_t */ 198 199 __u16 first_bucket; 200 union { 201 __u16 njournal_buckets; 202 __u16 keys; 203 }; 204 __u64 d[SB_JOURNAL_BUCKETS]; /* journal buckets */ 205 }; 206 207 static inline _Bool SB_IS_BDEV(const struct cache_sb *sb) 208 { 209 return sb->version == BCACHE_SB_VERSION_BDEV 210 || sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET; 211 } 212 213 BITMASK(CACHE_SYNC, struct cache_sb, flags, 0, 1); 214 BITMASK(CACHE_DISCARD, struct cache_sb, flags, 1, 1); 215 BITMASK(CACHE_REPLACEMENT, struct cache_sb, flags, 2, 3); 216 #define CACHE_REPLACEMENT_LRU 0U 217 #define CACHE_REPLACEMENT_FIFO 1U 218 #define CACHE_REPLACEMENT_RANDOM 2U 219 220 BITMASK(BDEV_CACHE_MODE, struct cache_sb, flags, 0, 4); 221 #define CACHE_MODE_WRITETHROUGH 0U 222 #define CACHE_MODE_WRITEBACK 1U 223 #define CACHE_MODE_WRITEAROUND 2U 224 #define CACHE_MODE_NONE 3U 225 BITMASK(BDEV_STATE, struct cache_sb, flags, 61, 2); 226 #define BDEV_STATE_NONE 0U 227 #define BDEV_STATE_CLEAN 1U 228 #define BDEV_STATE_DIRTY 2U 229 #define BDEV_STATE_STALE 3U 230 231 /* 232 * Magic numbers 233 * 234 * The various other data structures have their own magic numbers, which are 235 * xored with the first part of the cache set's UUID 236 */ 237 238 #define JSET_MAGIC 0x245235c1a3625032ULL 239 #define PSET_MAGIC 0x6750e15f87337f91ULL 240 #define BSET_MAGIC 0x90135c78b99e07f5ULL 241 242 static inline __u64 jset_magic(struct cache_sb *sb) 243 { 244 return sb->set_magic ^ JSET_MAGIC; 245 } 246 247 static inline __u64 pset_magic(struct cache_sb *sb) 248 { 249 return sb->set_magic ^ PSET_MAGIC; 250 } 251 252 static inline __u64 bset_magic(struct cache_sb *sb) 253 { 254 return sb->set_magic ^ BSET_MAGIC; 255 } 256 257 /* 258 * Journal 259 * 260 * On disk format for a journal entry: 261 * seq is monotonically increasing; every journal entry has its own unique 262 * sequence number. 263 * 264 * last_seq is the oldest journal entry that still has keys the btree hasn't 265 * flushed to disk yet. 266 * 267 * version is for on disk format changes. 268 */ 269 270 #define BCACHE_JSET_VERSION_UUIDv1 1 271 #define BCACHE_JSET_VERSION_UUID 1 /* Always latest UUID format */ 272 #define BCACHE_JSET_VERSION 1 273 274 struct jset { 275 __u64 csum; 276 __u64 magic; 277 __u64 seq; 278 __u32 version; 279 __u32 keys; 280 281 __u64 last_seq; 282 283 BKEY_PADDED(uuid_bucket); 284 BKEY_PADDED(btree_root); 285 __u16 btree_level; 286 __u16 pad[3]; 287 288 __u64 prio_bucket[MAX_CACHES_PER_SET]; 289 290 union { 291 struct bkey start[0]; 292 __u64 d[0]; 293 }; 294 }; 295 296 /* Bucket prios/gens */ 297 298 struct prio_set { 299 __u64 csum; 300 __u64 magic; 301 __u64 seq; 302 __u32 version; 303 __u32 pad; 304 305 __u64 next_bucket; 306 307 struct bucket_disk { 308 __u16 prio; 309 __u8 gen; 310 } __attribute((packed)) data[]; 311 }; 312 313 /* UUIDS - per backing device/flash only volume metadata */ 314 315 struct uuid_entry { 316 union { 317 struct { 318 __u8 uuid[16]; 319 __u8 label[32]; 320 __u32 first_reg; 321 __u32 last_reg; 322 __u32 invalidated; 323 324 __u32 flags; 325 /* Size of flash only volumes */ 326 __u64 sectors; 327 }; 328 329 __u8 pad[128]; 330 }; 331 }; 332 333 BITMASK(UUID_FLASH_ONLY, struct uuid_entry, flags, 0, 1); 334 335 /* Btree nodes */ 336 337 /* Version 1: Seed pointer into btree node checksum 338 */ 339 #define BCACHE_BSET_CSUM 1 340 #define BCACHE_BSET_VERSION 1 341 342 /* 343 * Btree nodes 344 * 345 * On disk a btree node is a list/log of these; within each set the keys are 346 * sorted 347 */ 348 struct bset { 349 __u64 csum; 350 __u64 magic; 351 __u64 seq; 352 __u32 version; 353 __u32 keys; 354 355 union { 356 struct bkey start[0]; 357 __u64 d[0]; 358 }; 359 }; 360 361 /* OBSOLETE */ 362 363 /* UUIDS - per backing device/flash only volume metadata */ 364 365 struct uuid_entry_v0 { 366 __u8 uuid[16]; 367 __u8 label[32]; 368 __u32 first_reg; 369 __u32 last_reg; 370 __u32 invalidated; 371 __u32 pad; 372 }; 373 374 #endif /* _LINUX_BCACHE_H */ 375
