root/include/uapi/linux/bcache.h

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INCLUDED FROM

DEFINITIONS

This source file includes following definitions.
  1. KEY_FIELD
  2. SET_KEY_OFFSET
  3. bkey_u64s
  4. bkey_bytes
  5. bkey_copy_key
  6. bkey_next
  7. bkey_idx
  8. SB_IS_BDEV
  9. jset_magic
  10. pset_magic
  11. bset_magic
   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 #ifndef _LINUX_BCACHE_H
   3 #define _LINUX_BCACHE_H
   4 
   5 /*
   6  * Bcache on disk data structures
   7  */
   8 
   9 #include <linux/types.h>
  10 
  11 #define BITMASK(name, type, field, offset, size)                \
  12 static inline __u64 name(const type *k)                         \
  13 { return (k->field >> offset) & ~(~0ULL << size); }             \
  14                                                                 \
  15 static inline void SET_##name(type *k, __u64 v)                 \
  16 {                                                               \
  17         k->field &= ~(~(~0ULL << size) << offset);              \
  18         k->field |= (v & ~(~0ULL << size)) << offset;           \
  19 }
  20 
  21 /* Btree keys - all units are in sectors */
  22 
  23 struct bkey {
  24         __u64   high;
  25         __u64   low;
  26         __u64   ptr[];
  27 };
  28 
  29 #define KEY_FIELD(name, field, offset, size)                            \
  30         BITMASK(name, struct bkey, field, offset, size)
  31 
  32 #define PTR_FIELD(name, offset, size)                                   \
  33 static inline __u64 name(const struct bkey *k, unsigned int i)          \
  34 { return (k->ptr[i] >> offset) & ~(~0ULL << size); }                    \
  35                                                                         \
  36 static inline void SET_##name(struct bkey *k, unsigned int i, __u64 v)  \
  37 {                                                                       \
  38         k->ptr[i] &= ~(~(~0ULL << size) << offset);                     \
  39         k->ptr[i] |= (v & ~(~0ULL << size)) << offset;                  \
  40 }
  41 
  42 #define KEY_SIZE_BITS           16
  43 #define KEY_MAX_U64S            8
  44 
  45 KEY_FIELD(KEY_PTRS,     high, 60, 3)
  46 KEY_FIELD(HEADER_SIZE,  high, 58, 2)
  47 KEY_FIELD(KEY_CSUM,     high, 56, 2)
  48 KEY_FIELD(KEY_PINNED,   high, 55, 1)
  49 KEY_FIELD(KEY_DIRTY,    high, 36, 1)
  50 
  51 KEY_FIELD(KEY_SIZE,     high, 20, KEY_SIZE_BITS)
  52 KEY_FIELD(KEY_INODE,    high, 0,  20)
  53 
  54 /* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */
  55 
  56 static inline __u64 KEY_OFFSET(const struct bkey *k)
  57 {
  58         return k->low;
  59 }
  60 
  61 static inline void SET_KEY_OFFSET(struct bkey *k, __u64 v)
  62 {
  63         k->low = v;
  64 }
  65 
  66 /*
  67  * The high bit being set is a relic from when we used it to do binary
  68  * searches - it told you where a key started. It's not used anymore,
  69  * and can probably be safely dropped.
  70  */
  71 #define KEY(inode, offset, size)                                        \
  72 ((struct bkey) {                                                        \
  73         .high = (1ULL << 63) | ((__u64) (size) << 20) | (inode),        \
  74         .low = (offset)                                                 \
  75 })
  76 
  77 #define ZERO_KEY                        KEY(0, 0, 0)
  78 
  79 #define MAX_KEY_INODE                   (~(~0 << 20))
  80 #define MAX_KEY_OFFSET                  (~0ULL >> 1)
  81 #define MAX_KEY                         KEY(MAX_KEY_INODE, MAX_KEY_OFFSET, 0)
  82 
  83 #define KEY_START(k)                    (KEY_OFFSET(k) - KEY_SIZE(k))
  84 #define START_KEY(k)                    KEY(KEY_INODE(k), KEY_START(k), 0)
  85 
  86 #define PTR_DEV_BITS                    12
  87 
  88 PTR_FIELD(PTR_DEV,                      51, PTR_DEV_BITS)
  89 PTR_FIELD(PTR_OFFSET,                   8,  43)
  90 PTR_FIELD(PTR_GEN,                      0,  8)
  91 
  92 #define PTR_CHECK_DEV                   ((1 << PTR_DEV_BITS) - 1)
  93 
  94 #define MAKE_PTR(gen, offset, dev)                                      \
  95         ((((__u64) dev) << 51) | ((__u64) offset) << 8 | gen)
  96 
  97 /* Bkey utility code */
  98 
  99 static inline unsigned long bkey_u64s(const struct bkey *k)
 100 {
 101         return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k);
 102 }
 103 
 104 static inline unsigned long bkey_bytes(const struct bkey *k)
 105 {
 106         return bkey_u64s(k) * sizeof(__u64);
 107 }
 108 
 109 #define bkey_copy(_dest, _src)  memcpy(_dest, _src, bkey_bytes(_src))
 110 
 111 static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src)
 112 {
 113         SET_KEY_INODE(dest, KEY_INODE(src));
 114         SET_KEY_OFFSET(dest, KEY_OFFSET(src));
 115 }
 116 
 117 static inline struct bkey *bkey_next(const struct bkey *k)
 118 {
 119         __u64 *d = (void *) k;
 120 
 121         return (struct bkey *) (d + bkey_u64s(k));
 122 }
 123 
 124 static inline struct bkey *bkey_idx(const struct bkey *k, unsigned int nr_keys)
 125 {
 126         __u64 *d = (void *) k;
 127 
 128         return (struct bkey *) (d + nr_keys);
 129 }
 130 /* Enough for a key with 6 pointers */
 131 #define BKEY_PAD                8
 132 
 133 #define BKEY_PADDED(key)                                        \
 134         union { struct bkey key; __u64 key ## _pad[BKEY_PAD]; }
 135 
 136 /* Superblock */
 137 
 138 /* Version 0: Cache device
 139  * Version 1: Backing device
 140  * Version 2: Seed pointer into btree node checksum
 141  * Version 3: Cache device with new UUID format
 142  * Version 4: Backing device with data offset
 143  */
 144 #define BCACHE_SB_VERSION_CDEV          0
 145 #define BCACHE_SB_VERSION_BDEV          1
 146 #define BCACHE_SB_VERSION_CDEV_WITH_UUID 3
 147 #define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4
 148 #define BCACHE_SB_MAX_VERSION           4
 149 
 150 #define SB_SECTOR                       8
 151 #define SB_SIZE                         4096
 152 #define SB_LABEL_SIZE                   32
 153 #define SB_JOURNAL_BUCKETS              256U
 154 /* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */
 155 #define MAX_CACHES_PER_SET              8
 156 
 157 #define BDEV_DATA_START_DEFAULT         16      /* sectors */
 158 
 159 struct cache_sb {
 160         __u64                   csum;
 161         __u64                   offset; /* sector where this sb was written */
 162         __u64                   version;
 163 
 164         __u8                    magic[16];
 165 
 166         __u8                    uuid[16];
 167         union {
 168                 __u8            set_uuid[16];
 169                 __u64           set_magic;
 170         };
 171         __u8                    label[SB_LABEL_SIZE];
 172 
 173         __u64                   flags;
 174         __u64                   seq;
 175         __u64                   pad[8];
 176 
 177         union {
 178         struct {
 179                 /* Cache devices */
 180                 __u64           nbuckets;       /* device size */
 181 
 182                 __u16           block_size;     /* sectors */
 183                 __u16           bucket_size;    /* sectors */
 184 
 185                 __u16           nr_in_set;
 186                 __u16           nr_this_dev;
 187         };
 188         struct {
 189                 /* Backing devices */
 190                 __u64           data_offset;
 191 
 192                 /*
 193                  * block_size from the cache device section is still used by
 194                  * backing devices, so don't add anything here until we fix
 195                  * things to not need it for backing devices anymore
 196                  */
 197         };
 198         };
 199 
 200         __u32                   last_mount;     /* time overflow in y2106 */
 201 
 202         __u16                   first_bucket;
 203         union {
 204                 __u16           njournal_buckets;
 205                 __u16           keys;
 206         };
 207         __u64                   d[SB_JOURNAL_BUCKETS];  /* journal buckets */
 208 };
 209 
 210 static inline _Bool SB_IS_BDEV(const struct cache_sb *sb)
 211 {
 212         return sb->version == BCACHE_SB_VERSION_BDEV
 213                 || sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET;
 214 }
 215 
 216 BITMASK(CACHE_SYNC,                     struct cache_sb, flags, 0, 1);
 217 BITMASK(CACHE_DISCARD,                  struct cache_sb, flags, 1, 1);
 218 BITMASK(CACHE_REPLACEMENT,              struct cache_sb, flags, 2, 3);
 219 #define CACHE_REPLACEMENT_LRU           0U
 220 #define CACHE_REPLACEMENT_FIFO          1U
 221 #define CACHE_REPLACEMENT_RANDOM        2U
 222 
 223 BITMASK(BDEV_CACHE_MODE,                struct cache_sb, flags, 0, 4);
 224 #define CACHE_MODE_WRITETHROUGH         0U
 225 #define CACHE_MODE_WRITEBACK            1U
 226 #define CACHE_MODE_WRITEAROUND          2U
 227 #define CACHE_MODE_NONE                 3U
 228 BITMASK(BDEV_STATE,                     struct cache_sb, flags, 61, 2);
 229 #define BDEV_STATE_NONE                 0U
 230 #define BDEV_STATE_CLEAN                1U
 231 #define BDEV_STATE_DIRTY                2U
 232 #define BDEV_STATE_STALE                3U
 233 
 234 /*
 235  * Magic numbers
 236  *
 237  * The various other data structures have their own magic numbers, which are
 238  * xored with the first part of the cache set's UUID
 239  */
 240 
 241 #define JSET_MAGIC                      0x245235c1a3625032ULL
 242 #define PSET_MAGIC                      0x6750e15f87337f91ULL
 243 #define BSET_MAGIC                      0x90135c78b99e07f5ULL
 244 
 245 static inline __u64 jset_magic(struct cache_sb *sb)
 246 {
 247         return sb->set_magic ^ JSET_MAGIC;
 248 }
 249 
 250 static inline __u64 pset_magic(struct cache_sb *sb)
 251 {
 252         return sb->set_magic ^ PSET_MAGIC;
 253 }
 254 
 255 static inline __u64 bset_magic(struct cache_sb *sb)
 256 {
 257         return sb->set_magic ^ BSET_MAGIC;
 258 }
 259 
 260 /*
 261  * Journal
 262  *
 263  * On disk format for a journal entry:
 264  * seq is monotonically increasing; every journal entry has its own unique
 265  * sequence number.
 266  *
 267  * last_seq is the oldest journal entry that still has keys the btree hasn't
 268  * flushed to disk yet.
 269  *
 270  * version is for on disk format changes.
 271  */
 272 
 273 #define BCACHE_JSET_VERSION_UUIDv1      1
 274 #define BCACHE_JSET_VERSION_UUID        1       /* Always latest UUID format */
 275 #define BCACHE_JSET_VERSION             1
 276 
 277 struct jset {
 278         __u64                   csum;
 279         __u64                   magic;
 280         __u64                   seq;
 281         __u32                   version;
 282         __u32                   keys;
 283 
 284         __u64                   last_seq;
 285 
 286         BKEY_PADDED(uuid_bucket);
 287         BKEY_PADDED(btree_root);
 288         __u16                   btree_level;
 289         __u16                   pad[3];
 290 
 291         __u64                   prio_bucket[MAX_CACHES_PER_SET];
 292 
 293         union {
 294                 struct bkey     start[0];
 295                 __u64           d[0];
 296         };
 297 };
 298 
 299 /* Bucket prios/gens */
 300 
 301 struct prio_set {
 302         __u64                   csum;
 303         __u64                   magic;
 304         __u64                   seq;
 305         __u32                   version;
 306         __u32                   pad;
 307 
 308         __u64                   next_bucket;
 309 
 310         struct bucket_disk {
 311                 __u16           prio;
 312                 __u8            gen;
 313         } __attribute((packed)) data[];
 314 };
 315 
 316 /* UUIDS - per backing device/flash only volume metadata */
 317 
 318 struct uuid_entry {
 319         union {
 320                 struct {
 321                         __u8    uuid[16];
 322                         __u8    label[32];
 323                         __u32   first_reg; /* time overflow in y2106 */
 324                         __u32   last_reg;
 325                         __u32   invalidated;
 326 
 327                         __u32   flags;
 328                         /* Size of flash only volumes */
 329                         __u64   sectors;
 330                 };
 331 
 332                 __u8            pad[128];
 333         };
 334 };
 335 
 336 BITMASK(UUID_FLASH_ONLY,        struct uuid_entry, flags, 0, 1);
 337 
 338 /* Btree nodes */
 339 
 340 /* Version 1: Seed pointer into btree node checksum
 341  */
 342 #define BCACHE_BSET_CSUM                1
 343 #define BCACHE_BSET_VERSION             1
 344 
 345 /*
 346  * Btree nodes
 347  *
 348  * On disk a btree node is a list/log of these; within each set the keys are
 349  * sorted
 350  */
 351 struct bset {
 352         __u64                   csum;
 353         __u64                   magic;
 354         __u64                   seq;
 355         __u32                   version;
 356         __u32                   keys;
 357 
 358         union {
 359                 struct bkey     start[0];
 360                 __u64           d[0];
 361         };
 362 };
 363 
 364 /* OBSOLETE */
 365 
 366 /* UUIDS - per backing device/flash only volume metadata */
 367 
 368 struct uuid_entry_v0 {
 369         __u8            uuid[16];
 370         __u8            label[32];
 371         __u32           first_reg;
 372         __u32           last_reg;
 373         __u32           invalidated;
 374         __u32           pad;
 375 };
 376 
 377 #endif /* _LINUX_BCACHE_H */
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