git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/bcachefs_format.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _BCACHEFS_FORMAT_H
   3 #define _BCACHEFS_FORMAT_H
   4
   5 /*
   6  * bcachefs on disk data structures
   7  *
   8  * OVERVIEW:
   9  *
  10  * There are three main types of on disk data structures in bcachefs (this is
  11  * reduced from 5 in bcache)
  12  *
  13  *  - superblock
  14  *  - journal
  15  *  - btree
  16  *
  17  * The btree is the primary structure; most metadata exists as keys in the
  18  * various btrees. There are only a small number of btrees, they're not
  19  * sharded - we have one btree for extents, another for inodes, et cetera.
  20  *
  21  * SUPERBLOCK:
  22  *
  23  * The superblock contains the location of the journal, the list of devices in
  24  * the filesystem, and in general any metadata we need in order to decide
  25  * whether we can start a filesystem or prior to reading the journal/btree
  26  * roots.
  27  *
  28  * The superblock is extensible, and most of the contents of the superblock are
  29  * in variable length, type tagged fields; see struct bch_sb_field.
  30  *
  31  * Backup superblocks do not reside in a fixed location; also, superblocks do
  32  * not have a fixed size. To locate backup superblocks we have struct
  33  * bch_sb_layout; we store a copy of this inside every superblock, and also
  34  * before the first superblock.
  35  *
  36  * JOURNAL:
  37  *
  38  * The journal primarily records btree updates in the order they occurred;
  39  * journal replay consists of just iterating over all the keys in the open
  40  * journal entries and re-inserting them into the btrees.
  41  *
  42  * The journal also contains entry types for the btree roots, and blacklisted
  43  * journal sequence numbers (see journal_seq_blacklist.c).
  44  *
  45  * BTREE:
  46  *
  47  * bcachefs btrees are copy on write b+ trees, where nodes are big (typically
  48  * 128k-256k) and log structured. We use struct btree_node for writing the first
  49  * entry in a given node (offset 0), and struct btree_node_entry for all
  50  * subsequent writes.
  51  *
  52  * After the header, btree node entries contain a list of keys in sorted order.
  53  * Values are stored inline with the keys; since values are variable length (and
  54  * keys effectively are variable length too, due to packing) we can't do random
  55  * access without building up additional in memory tables in the btree node read
  56  * path.
  57  *
  58  * BTREE KEYS (struct bkey):
  59  *
  60  * The various btrees share a common format for the key - so as to avoid
  61  * switching in fastpath lookup/comparison code - but define their own
  62  * structures for the key values.
  63  *
  64  * The size of a key/value pair is stored as a u8 in units of u64s, so the max
  65  * size is just under 2k. The common part also contains a type tag for the
  66  * value, and a format field indicating whether the key is packed or not (and
  67  * also meant to allow adding new key fields in the future, if desired).
  68  *
  69  * bkeys, when stored within a btree node, may also be packed. In that case, the
  70  * bkey_format in that node is used to unpack it. Packed bkeys mean that we can
  71  * be generous with field sizes in the common part of the key format (64 bit
  72  * inode number, 64 bit offset, 96 bit version field, etc.) for negligible cost.
  73  */
  74
  75 #include <asm/types.h>
  76 #include <asm/byteorder.h>
  77 #include <linux/kernel.h>
  78 #include <linux/uuid.h>
  79 #include "vstructs.h"
  80
  81 #ifdef __KERNEL__
  82 typedef uuid_t __uuid_t;
  83 #endif
  84
  85 #define BITMASK(name, type, field, offset, end)                         \
  86 static const __maybe_unused unsigned    name##_OFFSET = offset;         \
  87 static const __maybe_unused unsigned    name##_BITS = (end - offset);   \
  88                                                                         \
  89 static inline __u64 name(const type *k)                                 \
  90 {                                                                       \
  91         return (k->field >> offset) & ~(~0ULL << (end - offset));       \
  92 }                                                                       \
  93                                                                         \
  94 static inline void SET_##name(type *k, __u64 v)                         \
  95 {                                                                       \
  96         k->field &= ~(~(~0ULL << (end - offset)) << offset);            \
  97         k->field |= (v & ~(~0ULL << (end - offset))) << offset;         \
  98 }
  99
 100 #define LE_BITMASK(_bits, name, type, field, offset, end)               \
 101 static const __maybe_unused unsigned    name##_OFFSET = offset;         \
 102 static const __maybe_unused unsigned    name##_BITS = (end - offset);   \
 103 static const __maybe_unused __u##_bits  name##_MAX = (1ULL << (end - offset)) - 1;\
 104                                                                         \
 105 static inline __u64 name(const type *k)                                 \
 106 {                                                                       \
 107         return (__le##_bits##_to_cpu(k->field) >> offset) &             \
 108                 ~(~0ULL << (end - offset));                             \
 109 }                                                                       \
 110                                                                         \
 111 static inline void SET_##name(type *k, __u64 v)                         \
 112 {                                                                       \
 113         __u##_bits new = __le##_bits##_to_cpu(k->field);                \
 114                                                                         \
 115         new &= ~(~(~0ULL << (end - offset)) << offset);                 \
 116         new |= (v & ~(~0ULL << (end - offset))) << offset;              \
 117         k->field = __cpu_to_le##_bits(new);                             \
 118 }
 119
 120 #define LE16_BITMASK(n, t, f, o, e)     LE_BITMASK(16, n, t, f, o, e)
 121 #define LE32_BITMASK(n, t, f, o, e)     LE_BITMASK(32, n, t, f, o, e)
 122 #define LE64_BITMASK(n, t, f, o, e)     LE_BITMASK(64, n, t, f, o, e)
 123
 124 struct bkey_format {
 125         __u8            key_u64s;
 126         __u8            nr_fields;
 127         /* One unused slot for now: */
 128         __u8            bits_per_field[6];
 129         __le64          field_offset[6];
 130 };
 131
 132 /* Btree keys - all units are in sectors */
 133
 134 struct bpos {
 135         /*
 136          * Word order matches machine byte order - btree code treats a bpos as a
 137          * single large integer, for search/comparison purposes
 138          *
 139          * Note that wherever a bpos is embedded in another on disk data
 140          * structure, it has to be byte swabbed when reading in metadata that
 141          * wasn't written in native endian order:
 142          */
 143 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 144         __u32           snapshot;
 145         __u64           offset;
 146         __u64           inode;
 147 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 148         __u64           inode;
 149         __u64           offset;         /* Points to end of extent - sectors */
 150         __u32           snapshot;
 151 #else
 152 #error edit for your odd byteorder.
 153 #endif
 154 } __packed
 155 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 156 __aligned(4)
 157 #endif
 158 ;
 159
 160 #define KEY_INODE_MAX                   ((__u64)~0ULL)
 161 #define KEY_OFFSET_MAX                  ((__u64)~0ULL)
 162 #define KEY_SNAPSHOT_MAX                ((__u32)~0U)
 163 #define KEY_SIZE_MAX                    ((__u32)~0U)
 164
 165 static inline struct bpos SPOS(__u64 inode, __u64 offset, __u32 snapshot)
 166 {
 167         return (struct bpos) {
 168                 .inode          = inode,
 169                 .offset         = offset,
 170                 .snapshot       = snapshot,
 171         };
 172 }
 173
 174 #define POS_MIN                         SPOS(0, 0, 0)
 175 #define POS_MAX                         SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, 0)
 176 #define SPOS_MAX                        SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, KEY_SNAPSHOT_MAX)
 177 #define POS(_inode, _offset)            SPOS(_inode, _offset, 0)
 178
 179 /* Empty placeholder struct, for container_of() */
 180 struct bch_val {
 181         __u64           __nothing[0];
 182 };
 183
 184 struct bversion {
 185 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 186         __u64           lo;
 187         __u32           hi;
 188 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 189         __u32           hi;
 190         __u64           lo;
 191 #endif
 192 } __packed __aligned(4);
 193
 194 struct bkey {
 195         /* Size of combined key and value, in u64s */
 196         __u8            u64s;
 197
 198         /* Format of key (0 for format local to btree node) */
 199 #if defined(__LITTLE_ENDIAN_BITFIELD)
 200         __u8            format:7,
 201                         needs_whiteout:1;
 202 #elif defined (__BIG_ENDIAN_BITFIELD)
 203         __u8            needs_whiteout:1,
 204                         format:7;
 205 #else
 206 #error edit for your odd byteorder.
 207 #endif
 208
 209         /* Type of the value */
 210         __u8            type;
 211
 212 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 213         __u8            pad[1];
 214
 215         struct bversion version;
 216         __u32           size;           /* extent size, in sectors */
 217         struct bpos     p;
 218 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 219         struct bpos     p;
 220         __u32           size;           /* extent size, in sectors */
 221         struct bversion version;
 222
 223         __u8            pad[1];
 224 #endif
 225 } __packed __aligned(8);
 226
 227 struct bkey_packed {
 228         __u64           _data[0];
 229
 230         /* Size of combined key and value, in u64s */
 231         __u8            u64s;
 232
 233         /* Format of key (0 for format local to btree node) */
 234
 235         /*
 236          * XXX: next incompat on disk format change, switch format and
 237          * needs_whiteout - bkey_packed() will be cheaper if format is the high
 238          * bits of the bitfield
 239          */
 240 #if defined(__LITTLE_ENDIAN_BITFIELD)
 241         __u8            format:7,
 242                         needs_whiteout:1;
 243 #elif defined (__BIG_ENDIAN_BITFIELD)
 244         __u8            needs_whiteout:1,
 245                         format:7;
 246 #endif
 247
 248         /* Type of the value */
 249         __u8            type;
 250         __u8            key_start[0];
 251
 252         /*
 253          * We copy bkeys with struct assignment in various places, and while
 254          * that shouldn't be done with packed bkeys we can't disallow it in C,
 255          * and it's legal to cast a bkey to a bkey_packed  - so padding it out
 256          * to the same size as struct bkey should hopefully be safest.
 257          */
 258         __u8            pad[sizeof(struct bkey) - 3];
 259 } __packed __aligned(8);
 260
 261 typedef struct {
 262         __le64                  lo;
 263         __le64                  hi;
 264 } bch_le128;
 265
 266 #define BKEY_U64s                       (sizeof(struct bkey) / sizeof(__u64))
 267 #define BKEY_U64s_MAX                   U8_MAX
 268 #define BKEY_VAL_U64s_MAX               (BKEY_U64s_MAX - BKEY_U64s)
 269
 270 #define KEY_PACKED_BITS_START           24
 271
 272 #define KEY_FORMAT_LOCAL_BTREE          0
 273 #define KEY_FORMAT_CURRENT              1
 274
 275 enum bch_bkey_fields {
 276         BKEY_FIELD_INODE,
 277         BKEY_FIELD_OFFSET,
 278         BKEY_FIELD_SNAPSHOT,
 279         BKEY_FIELD_SIZE,
 280         BKEY_FIELD_VERSION_HI,
 281         BKEY_FIELD_VERSION_LO,
 282         BKEY_NR_FIELDS,
 283 };
 284
 285 #define bkey_format_field(name, field)                                  \
 286         [BKEY_FIELD_##name] = (sizeof(((struct bkey *) NULL)->field) * 8)
 287
 288 #define BKEY_FORMAT_CURRENT                                             \
 289 ((struct bkey_format) {                                                 \
 290         .key_u64s       = BKEY_U64s,                                    \
 291         .nr_fields      = BKEY_NR_FIELDS,                               \
 292         .bits_per_field = {                                             \
 293                 bkey_format_field(INODE,        p.inode),               \
 294                 bkey_format_field(OFFSET,       p.offset),              \
 295                 bkey_format_field(SNAPSHOT,     p.snapshot),            \
 296                 bkey_format_field(SIZE,         size),                  \
 297                 bkey_format_field(VERSION_HI,   version.hi),            \
 298                 bkey_format_field(VERSION_LO,   version.lo),            \
 299         },                                                              \
 300 })
 301
 302 /* bkey with inline value */
 303 struct bkey_i {
 304         __u64                   _data[0];
 305
 306         struct bkey     k;
 307         struct bch_val  v;
 308 };
 309
 310 #define POS_KEY(_pos)                                                   \
 311 ((struct bkey) {                                                        \
 312         .u64s           = BKEY_U64s,                                    \
 313         .format         = KEY_FORMAT_CURRENT,                           \
 314         .p              = _pos,                                         \
 315 })
 316
 317 #define KEY(_inode, _offset, _size)                                     \
 318 ((struct bkey) {                                                        \
 319         .u64s           = BKEY_U64s,                                    \
 320         .format         = KEY_FORMAT_CURRENT,                           \
 321         .p              = POS(_inode, _offset),                         \
 322         .size           = _size,                                        \
 323 })
 324
 325 static inline void bkey_init(struct bkey *k)
 326 {
 327         *k = KEY(0, 0, 0);
 328 }
 329
 330 #define bkey_bytes(_k)          ((_k)->u64s * sizeof(__u64))
 331
 332 #define __BKEY_PADDED(key, pad)                                 \
 333         struct bkey_i key; __u64 key ## _pad[pad]
 334
 335 /*
 336  * - DELETED keys are used internally to mark keys that should be ignored but
 337  *   override keys in composition order.  Their version number is ignored.
 338  *
 339  * - DISCARDED keys indicate that the data is all 0s because it has been
 340  *   discarded. DISCARDs may have a version; if the version is nonzero the key
 341  *   will be persistent, otherwise the key will be dropped whenever the btree
 342  *   node is rewritten (like DELETED keys).
 343  *
 344  * - ERROR: any read of the data returns a read error, as the data was lost due
 345  *   to a failing device. Like DISCARDED keys, they can be removed (overridden)
 346  *   by new writes or cluster-wide GC. Node repair can also overwrite them with
 347  *   the same or a more recent version number, but not with an older version
 348  *   number.
 349  *
 350  * - WHITEOUT: for hash table btrees
 351  */
 352 #define BCH_BKEY_TYPES()                                \
 353         x(deleted,              0)                      \
 354         x(whiteout,             1)                      \
 355         x(error,                2)                      \
 356         x(cookie,               3)                      \
 357         x(hash_whiteout,        4)                      \
 358         x(btree_ptr,            5)                      \
 359         x(extent,               6)                      \
 360         x(reservation,          7)                      \
 361         x(inode,                8)                      \
 362         x(inode_generation,     9)                      \
 363         x(dirent,               10)                     \
 364         x(xattr,                11)                     \
 365         x(alloc,                12)                     \
 366         x(quota,                13)                     \
 367         x(stripe,               14)                     \
 368         x(reflink_p,            15)                     \
 369         x(reflink_v,            16)                     \
 370         x(inline_data,          17)                     \
 371         x(btree_ptr_v2,         18)                     \
 372         x(indirect_inline_data, 19)                     \
 373         x(alloc_v2,             20)                     \
 374         x(subvolume,            21)                     \
 375         x(snapshot,             22)                     \
 376         x(inode_v2,             23)                     \
 377         x(alloc_v3,             24)                     \
 378         x(set,                  25)                     \
 379         x(lru,                  26)                     \
 380         x(alloc_v4,             27)                     \
 381         x(backpointer,          28)                     \
 382         x(inode_v3,             29)                     \
 383         x(bucket_gens,          30)                     \
 384         x(snapshot_tree,        31)                     \
 385         x(logged_op_truncate,   32)                     \
 386         x(logged_op_finsert,    33)
 387
 388 enum bch_bkey_type {
 389 #define x(name, nr) KEY_TYPE_##name     = nr,
 390         BCH_BKEY_TYPES()
 391 #undef x
 392         KEY_TYPE_MAX,
 393 };
 394
 395 struct bch_deleted {
 396         struct bch_val          v;
 397 };
 398
 399 struct bch_whiteout {
 400         struct bch_val          v;
 401 };
 402
 403 struct bch_error {
 404         struct bch_val          v;
 405 };
 406
 407 struct bch_cookie {
 408         struct bch_val          v;
 409         __le64                  cookie;
 410 };
 411
 412 struct bch_hash_whiteout {
 413         struct bch_val          v;
 414 };
 415
 416 struct bch_set {
 417         struct bch_val          v;
 418 };
 419
 420 /* 128 bits, sufficient for cryptographic MACs: */
 421 struct bch_csum {
 422         __le64                  lo;
 423         __le64                  hi;
 424 } __packed __aligned(8);
 425
 426 struct bch_backpointer {
 427         struct bch_val          v;
 428         __u8                    btree_id;
 429         __u8                    level;
 430         __u8                    data_type;
 431         __u64                   bucket_offset:40;
 432         __u32                   bucket_len;
 433         struct bpos             pos;
 434 } __packed __aligned(8);
 435
 436 /* LRU btree: */
 437
 438 struct bch_lru {
 439         struct bch_val          v;
 440         __le64                  idx;
 441 } __packed __aligned(8);
 442
 443 #define LRU_ID_STRIPES          (1U << 16)
 444
 445 /* Optional/variable size superblock sections: */
 446
 447 struct bch_sb_field {
 448         __u64                   _data[0];
 449         __le32                  u64s;
 450         __le32                  type;
 451 };
 452
 453 #define BCH_SB_FIELDS()                         \
 454         x(journal,                      0)      \
 455         x(members_v1,                   1)      \
 456         x(crypt,                        2)      \
 457         x(replicas_v0,                  3)      \
 458         x(quota,                        4)      \
 459         x(disk_groups,                  5)      \
 460         x(clean,                        6)      \
 461         x(replicas,                     7)      \
 462         x(journal_seq_blacklist,        8)      \
 463         x(journal_v2,                   9)      \
 464         x(counters,                     10)     \
 465         x(members_v2,                   11)     \
 466         x(errors,                       12)     \
 467         x(ext,                          13)     \
 468         x(downgrade,                    14)
 469
 470 #include "alloc_background_format.h"
 471 #include "extents_format.h"
 472 #include "reflink_format.h"
 473 #include "ec_format.h"
 474 #include "inode_format.h"
 475 #include "dirent_format.h"
 476 #include "xattr_format.h"
 477 #include "quota_format.h"
 478 #include "logged_ops_format.h"
 479 #include "snapshot_format.h"
 480 #include "subvolume_format.h"
 481 #include "sb-counters_format.h"
 482
 483 enum bch_sb_field_type {
 484 #define x(f, nr)        BCH_SB_FIELD_##f = nr,
 485         BCH_SB_FIELDS()
 486 #undef x
 487         BCH_SB_FIELD_NR
 488 };
 489
 490 /*
 491  * Most superblock fields are replicated in all device's superblocks - a few are
 492  * not:
 493  */
 494 #define BCH_SINGLE_DEVICE_SB_FIELDS             \
 495         ((1U << BCH_SB_FIELD_journal)|          \
 496          (1U << BCH_SB_FIELD_journal_v2))
 497
 498 /* BCH_SB_FIELD_journal: */
 499
 500 struct bch_sb_field_journal {
 501         struct bch_sb_field     field;
 502         __le64                  buckets[];
 503 };
 504
 505 struct bch_sb_field_journal_v2 {
 506         struct bch_sb_field     field;
 507
 508         struct bch_sb_field_journal_v2_entry {
 509                 __le64          start;
 510                 __le64          nr;
 511         }                       d[];
 512 };
 513
 514 /* BCH_SB_FIELD_members_v1: */
 515
 516 #define BCH_MIN_NR_NBUCKETS     (1 << 6)
 517
 518 #define BCH_IOPS_MEASUREMENTS()                 \
 519         x(seqread,      0)                      \
 520         x(seqwrite,     1)                      \
 521         x(randread,     2)                      \
 522         x(randwrite,    3)
 523
 524 enum bch_iops_measurement {
 525 #define x(t, n) BCH_IOPS_##t = n,
 526         BCH_IOPS_MEASUREMENTS()
 527 #undef x
 528         BCH_IOPS_NR
 529 };
 530
 531 #define BCH_MEMBER_ERROR_TYPES()                \
 532         x(read,         0)                      \
 533         x(write,        1)                      \
 534         x(checksum,     2)
 535
 536 enum bch_member_error_type {
 537 #define x(t, n) BCH_MEMBER_ERROR_##t = n,
 538         BCH_MEMBER_ERROR_TYPES()
 539 #undef x
 540         BCH_MEMBER_ERROR_NR
 541 };
 542
 543 struct bch_member {
 544         __uuid_t                uuid;
 545         __le64                  nbuckets;       /* device size */
 546         __le16                  first_bucket;   /* index of first bucket used */
 547         __le16                  bucket_size;    /* sectors */
 548         __le32                  pad;
 549         __le64                  last_mount;     /* time_t */
 550
 551         __le64                  flags;
 552         __le32                  iops[4];
 553         __le64                  errors[BCH_MEMBER_ERROR_NR];
 554         __le64                  errors_at_reset[BCH_MEMBER_ERROR_NR];
 555         __le64                  errors_reset_time;
 556         __le64                  seq;
 557 };
 558
 559 #define BCH_MEMBER_V1_BYTES     56
 560
 561 LE64_BITMASK(BCH_MEMBER_STATE,          struct bch_member, flags,  0,  4)
 562 /* 4-14 unused, was TIER, HAS_(META)DATA, REPLACEMENT */
 563 LE64_BITMASK(BCH_MEMBER_DISCARD,        struct bch_member, flags, 14, 15)
 564 LE64_BITMASK(BCH_MEMBER_DATA_ALLOWED,   struct bch_member, flags, 15, 20)
 565 LE64_BITMASK(BCH_MEMBER_GROUP,          struct bch_member, flags, 20, 28)
 566 LE64_BITMASK(BCH_MEMBER_DURABILITY,     struct bch_member, flags, 28, 30)
 567 LE64_BITMASK(BCH_MEMBER_FREESPACE_INITIALIZED,
 568                                         struct bch_member, flags, 30, 31)
 569
 570 #if 0
 571 LE64_BITMASK(BCH_MEMBER_NR_READ_ERRORS, struct bch_member, flags[1], 0,  20);
 572 LE64_BITMASK(BCH_MEMBER_NR_WRITE_ERRORS,struct bch_member, flags[1], 20, 40);
 573 #endif
 574
 575 #define BCH_MEMBER_STATES()                     \
 576         x(rw,           0)                      \
 577         x(ro,           1)                      \
 578         x(failed,       2)                      \
 579         x(spare,        3)
 580
 581 enum bch_member_state {
 582 #define x(t, n) BCH_MEMBER_STATE_##t = n,
 583         BCH_MEMBER_STATES()
 584 #undef x
 585         BCH_MEMBER_STATE_NR
 586 };
 587
 588 struct bch_sb_field_members_v1 {
 589         struct bch_sb_field     field;
 590         struct bch_member       _members[]; //Members are now variable size
 591 };
 592
 593 struct bch_sb_field_members_v2 {
 594         struct bch_sb_field     field;
 595         __le16                  member_bytes; //size of single member entry
 596         u8                      pad[6];
 597         struct bch_member       _members[];
 598 };
 599
 600 /* BCH_SB_FIELD_crypt: */
 601
 602 struct nonce {
 603         __le32                  d[4];
 604 };
 605
 606 struct bch_key {
 607         __le64                  key[4];
 608 };
 609
 610 #define BCH_KEY_MAGIC                                   \
 611         (((__u64) 'b' <<  0)|((__u64) 'c' <<  8)|               \
 612          ((__u64) 'h' << 16)|((__u64) '*' << 24)|               \
 613          ((__u64) '*' << 32)|((__u64) 'k' << 40)|               \
 614          ((__u64) 'e' << 48)|((__u64) 'y' << 56))
 615
 616 struct bch_encrypted_key {
 617         __le64                  magic;
 618         struct bch_key          key;
 619 };
 620
 621 /*
 622  * If this field is present in the superblock, it stores an encryption key which
 623  * is used encrypt all other data/metadata. The key will normally be encrypted
 624  * with the key userspace provides, but if encryption has been turned off we'll
 625  * just store the master key unencrypted in the superblock so we can access the
 626  * previously encrypted data.
 627  */
 628 struct bch_sb_field_crypt {
 629         struct bch_sb_field     field;
 630
 631         __le64                  flags;
 632         __le64                  kdf_flags;
 633         struct bch_encrypted_key key;
 634 };
 635
 636 LE64_BITMASK(BCH_CRYPT_KDF_TYPE,        struct bch_sb_field_crypt, flags, 0, 4);
 637
 638 enum bch_kdf_types {
 639         BCH_KDF_SCRYPT          = 0,
 640         BCH_KDF_NR              = 1,
 641 };
 642
 643 /* stored as base 2 log of scrypt params: */
 644 LE64_BITMASK(BCH_KDF_SCRYPT_N,  struct bch_sb_field_crypt, kdf_flags,  0, 16);
 645 LE64_BITMASK(BCH_KDF_SCRYPT_R,  struct bch_sb_field_crypt, kdf_flags, 16, 32);
 646 LE64_BITMASK(BCH_KDF_SCRYPT_P,  struct bch_sb_field_crypt, kdf_flags, 32, 48);
 647
 648 /* BCH_SB_FIELD_replicas: */
 649
 650 #define BCH_DATA_TYPES()                \
 651         x(free,         0)              \
 652         x(sb,           1)              \
 653         x(journal,      2)              \
 654         x(btree,        3)              \
 655         x(user,         4)              \
 656         x(cached,       5)              \
 657         x(parity,       6)              \
 658         x(stripe,       7)              \
 659         x(need_gc_gens, 8)              \
 660         x(need_discard, 9)
 661
 662 enum bch_data_type {
 663 #define x(t, n) BCH_DATA_##t,
 664         BCH_DATA_TYPES()
 665 #undef x
 666         BCH_DATA_NR
 667 };
 668
 669 static inline bool data_type_is_empty(enum bch_data_type type)
 670 {
 671         switch (type) {
 672         case BCH_DATA_free:
 673         case BCH_DATA_need_gc_gens:
 674         case BCH_DATA_need_discard:
 675                 return true;
 676         default:
 677                 return false;
 678         }
 679 }
 680
 681 static inline bool data_type_is_hidden(enum bch_data_type type)
 682 {
 683         switch (type) {
 684         case BCH_DATA_sb:
 685         case BCH_DATA_journal:
 686                 return true;
 687         default:
 688                 return false;
 689         }
 690 }
 691
 692 struct bch_replicas_entry_v0 {
 693         __u8                    data_type;
 694         __u8                    nr_devs;
 695         __u8                    devs[];
 696 } __packed;
 697
 698 struct bch_sb_field_replicas_v0 {
 699         struct bch_sb_field     field;
 700         struct bch_replicas_entry_v0 entries[];
 701 } __packed __aligned(8);
 702
 703 struct bch_replicas_entry_v1 {
 704         __u8                    data_type;
 705         __u8                    nr_devs;
 706         __u8                    nr_required;
 707         __u8                    devs[];
 708 } __packed;
 709
 710 #define replicas_entry_bytes(_i)                                        \
 711         (offsetof(typeof(*(_i)), devs) + (_i)->nr_devs)
 712
 713 struct bch_sb_field_replicas {
 714         struct bch_sb_field     field;
 715         struct bch_replicas_entry_v1 entries[];
 716 } __packed __aligned(8);
 717
 718 /* BCH_SB_FIELD_disk_groups: */
 719
 720 #define BCH_SB_LABEL_SIZE               32
 721
 722 struct bch_disk_group {
 723         __u8                    label[BCH_SB_LABEL_SIZE];
 724         __le64                  flags[2];
 725 } __packed __aligned(8);
 726
 727 LE64_BITMASK(BCH_GROUP_DELETED,         struct bch_disk_group, flags[0], 0,  1)
 728 LE64_BITMASK(BCH_GROUP_DATA_ALLOWED,    struct bch_disk_group, flags[0], 1,  6)
 729 LE64_BITMASK(BCH_GROUP_PARENT,          struct bch_disk_group, flags[0], 6, 24)
 730
 731 struct bch_sb_field_disk_groups {
 732         struct bch_sb_field     field;
 733         struct bch_disk_group   entries[];
 734 } __packed __aligned(8);
 735
 736 /*
 737  * On clean shutdown, store btree roots and current journal sequence number in
 738  * the superblock:
 739  */
 740 struct jset_entry {
 741         __le16                  u64s;
 742         __u8                    btree_id;
 743         __u8                    level;
 744         __u8                    type; /* designates what this jset holds */
 745         __u8                    pad[3];
 746
 747         struct bkey_i           start[0];
 748         __u64                   _data[];
 749 };
 750
 751 struct bch_sb_field_clean {
 752         struct bch_sb_field     field;
 753
 754         __le32                  flags;
 755         __le16                  _read_clock; /* no longer used */
 756         __le16                  _write_clock;
 757         __le64                  journal_seq;
 758
 759         struct jset_entry       start[0];
 760         __u64                   _data[];
 761 };
 762
 763 struct journal_seq_blacklist_entry {
 764         __le64                  start;
 765         __le64                  end;
 766 };
 767
 768 struct bch_sb_field_journal_seq_blacklist {
 769         struct bch_sb_field     field;
 770         struct journal_seq_blacklist_entry start[];
 771 };
 772
 773 struct bch_sb_field_errors {
 774         struct bch_sb_field     field;
 775         struct bch_sb_field_error_entry {
 776                 __le64          v;
 777                 __le64          last_error_time;
 778         }                       entries[];
 779 };
 780
 781 LE64_BITMASK(BCH_SB_ERROR_ENTRY_ID,     struct bch_sb_field_error_entry, v,  0, 16);
 782 LE64_BITMASK(BCH_SB_ERROR_ENTRY_NR,     struct bch_sb_field_error_entry, v, 16, 64);
 783
 784 struct bch_sb_field_ext {
 785         struct bch_sb_field     field;
 786         __le64                  recovery_passes_required[2];
 787         __le64                  errors_silent[8];
 788 };
 789
 790 struct bch_sb_field_downgrade_entry {
 791         __le16                  version;
 792         __le64                  recovery_passes[2];
 793         __le16                  nr_errors;
 794         __le16                  errors[] __counted_by(nr_errors);
 795 } __packed __aligned(2);
 796
 797 struct bch_sb_field_downgrade {
 798         struct bch_sb_field     field;
 799         struct bch_sb_field_downgrade_entry entries[];
 800 };
 801
 802 /* Superblock: */
 803
 804 /*
 805  * New versioning scheme:
 806  * One common version number for all on disk data structures - superblock, btree
 807  * nodes, journal entries
 808  */
 809 #define BCH_VERSION_MAJOR(_v)           ((__u16) ((_v) >> 10))
 810 #define BCH_VERSION_MINOR(_v)           ((__u16) ((_v) & ~(~0U << 10)))
 811 #define BCH_VERSION(_major, _minor)     (((_major) << 10)|(_minor) << 0)
 812
 813 /*
 814  * field 1:             version name
 815  * field 2:             BCH_VERSION(major, minor)
 816  * field 3:             recovery passess required on upgrade
 817  */
 818 #define BCH_METADATA_VERSIONS()                                         \
 819         x(bkey_renumber,                BCH_VERSION(0, 10))             \
 820         x(inode_btree_change,           BCH_VERSION(0, 11))             \
 821         x(snapshot,                     BCH_VERSION(0, 12))             \
 822         x(inode_backpointers,           BCH_VERSION(0, 13))             \
 823         x(btree_ptr_sectors_written,    BCH_VERSION(0, 14))             \
 824         x(snapshot_2,                   BCH_VERSION(0, 15))             \
 825         x(reflink_p_fix,                BCH_VERSION(0, 16))             \
 826         x(subvol_dirent,                BCH_VERSION(0, 17))             \
 827         x(inode_v2,                     BCH_VERSION(0, 18))             \
 828         x(freespace,                    BCH_VERSION(0, 19))             \
 829         x(alloc_v4,                     BCH_VERSION(0, 20))             \
 830         x(new_data_types,               BCH_VERSION(0, 21))             \
 831         x(backpointers,                 BCH_VERSION(0, 22))             \
 832         x(inode_v3,                     BCH_VERSION(0, 23))             \
 833         x(unwritten_extents,            BCH_VERSION(0, 24))             \
 834         x(bucket_gens,                  BCH_VERSION(0, 25))             \
 835         x(lru_v2,                       BCH_VERSION(0, 26))             \
 836         x(fragmentation_lru,            BCH_VERSION(0, 27))             \
 837         x(no_bps_in_alloc_keys,         BCH_VERSION(0, 28))             \
 838         x(snapshot_trees,               BCH_VERSION(0, 29))             \
 839         x(major_minor,                  BCH_VERSION(1,  0))             \
 840         x(snapshot_skiplists,           BCH_VERSION(1,  1))             \
 841         x(deleted_inodes,               BCH_VERSION(1,  2))             \
 842         x(rebalance_work,               BCH_VERSION(1,  3))             \
 843         x(member_seq,                   BCH_VERSION(1,  4))
 844
 845 enum bcachefs_metadata_version {
 846         bcachefs_metadata_version_min = 9,
 847 #define x(t, n) bcachefs_metadata_version_##t = n,
 848         BCH_METADATA_VERSIONS()
 849 #undef x
 850         bcachefs_metadata_version_max
 851 };
 852
 853 static const __maybe_unused
 854 unsigned bcachefs_metadata_required_upgrade_below = bcachefs_metadata_version_rebalance_work;
 855
 856 #define bcachefs_metadata_version_current       (bcachefs_metadata_version_max - 1)
 857
 858 #define BCH_SB_SECTOR                   8
 859 #define BCH_SB_MEMBERS_MAX              64 /* XXX kill */
 860
 861 struct bch_sb_layout {
 862         __uuid_t                magic;  /* bcachefs superblock UUID */
 863         __u8                    layout_type;
 864         __u8                    sb_max_size_bits; /* base 2 of 512 byte sectors */
 865         __u8                    nr_superblocks;
 866         __u8                    pad[5];
 867         __le64                  sb_offset[61];
 868 } __packed __aligned(8);
 869
 870 #define BCH_SB_LAYOUT_SECTOR    7
 871
 872 /*
 873  * @offset      - sector where this sb was written
 874  * @version     - on disk format version
 875  * @version_min - Oldest metadata version this filesystem contains; so we can
 876  *                safely drop compatibility code and refuse to mount filesystems
 877  *                we'd need it for
 878  * @magic       - identifies as a bcachefs superblock (BCHFS_MAGIC)
 879  * @seq         - incremented each time superblock is written
 880  * @uuid        - used for generating various magic numbers and identifying
 881  *                member devices, never changes
 882  * @user_uuid   - user visible UUID, may be changed
 883  * @label       - filesystem label
 884  * @seq         - identifies most recent superblock, incremented each time
 885  *                superblock is written
 886  * @features    - enabled incompatible features
 887  */
 888 struct bch_sb {
 889         struct bch_csum         csum;
 890         __le16                  version;
 891         __le16                  version_min;
 892         __le16                  pad[2];
 893         __uuid_t                magic;
 894         __uuid_t                uuid;
 895         __uuid_t                user_uuid;
 896         __u8                    label[BCH_SB_LABEL_SIZE];
 897         __le64                  offset;
 898         __le64                  seq;
 899
 900         __le16                  block_size;
 901         __u8                    dev_idx;
 902         __u8                    nr_devices;
 903         __le32                  u64s;
 904
 905         __le64                  time_base_lo;
 906         __le32                  time_base_hi;
 907         __le32                  time_precision;
 908
 909         __le64                  flags[7];
 910         __le64                  write_time;
 911         __le64                  features[2];
 912         __le64                  compat[2];
 913
 914         struct bch_sb_layout    layout;
 915
 916         struct bch_sb_field     start[0];
 917         __le64                  _data[];
 918 } __packed __aligned(8);
 919
 920 /*
 921  * Flags:
 922  * BCH_SB_INITALIZED    - set on first mount
 923  * BCH_SB_CLEAN         - did we shut down cleanly? Just a hint, doesn't affect
 924  *                        behaviour of mount/recovery path:
 925  * BCH_SB_INODE_32BIT   - limit inode numbers to 32 bits
 926  * BCH_SB_128_BIT_MACS  - 128 bit macs instead of 80
 927  * BCH_SB_ENCRYPTION_TYPE - if nonzero encryption is enabled; overrides
 928  *                         DATA/META_CSUM_TYPE. Also indicates encryption
 929  *                         algorithm in use, if/when we get more than one
 930  */
 931
 932 LE16_BITMASK(BCH_SB_BLOCK_SIZE,         struct bch_sb, block_size, 0, 16);
 933
 934 LE64_BITMASK(BCH_SB_INITIALIZED,        struct bch_sb, flags[0],  0,  1);
 935 LE64_BITMASK(BCH_SB_CLEAN,              struct bch_sb, flags[0],  1,  2);
 936 LE64_BITMASK(BCH_SB_CSUM_TYPE,          struct bch_sb, flags[0],  2,  8);
 937 LE64_BITMASK(BCH_SB_ERROR_ACTION,       struct bch_sb, flags[0],  8, 12);
 938
 939 LE64_BITMASK(BCH_SB_BTREE_NODE_SIZE,    struct bch_sb, flags[0], 12, 28);
 940
 941 LE64_BITMASK(BCH_SB_GC_RESERVE,         struct bch_sb, flags[0], 28, 33);
 942 LE64_BITMASK(BCH_SB_ROOT_RESERVE,       struct bch_sb, flags[0], 33, 40);
 943
 944 LE64_BITMASK(BCH_SB_META_CSUM_TYPE,     struct bch_sb, flags[0], 40, 44);
 945 LE64_BITMASK(BCH_SB_DATA_CSUM_TYPE,     struct bch_sb, flags[0], 44, 48);
 946
 947 LE64_BITMASK(BCH_SB_META_REPLICAS_WANT, struct bch_sb, flags[0], 48, 52);
 948 LE64_BITMASK(BCH_SB_DATA_REPLICAS_WANT, struct bch_sb, flags[0], 52, 56);
 949
 950 LE64_BITMASK(BCH_SB_POSIX_ACL,          struct bch_sb, flags[0], 56, 57);
 951 LE64_BITMASK(BCH_SB_USRQUOTA,           struct bch_sb, flags[0], 57, 58);
 952 LE64_BITMASK(BCH_SB_GRPQUOTA,           struct bch_sb, flags[0], 58, 59);
 953 LE64_BITMASK(BCH_SB_PRJQUOTA,           struct bch_sb, flags[0], 59, 60);
 954
 955 LE64_BITMASK(BCH_SB_HAS_ERRORS,         struct bch_sb, flags[0], 60, 61);
 956 LE64_BITMASK(BCH_SB_HAS_TOPOLOGY_ERRORS,struct bch_sb, flags[0], 61, 62);
 957
 958 LE64_BITMASK(BCH_SB_BIG_ENDIAN,         struct bch_sb, flags[0], 62, 63);
 959
 960 LE64_BITMASK(BCH_SB_STR_HASH_TYPE,      struct bch_sb, flags[1],  0,  4);
 961 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_LO,struct bch_sb, flags[1],  4,  8);
 962 LE64_BITMASK(BCH_SB_INODE_32BIT,        struct bch_sb, flags[1],  8,  9);
 963
 964 LE64_BITMASK(BCH_SB_128_BIT_MACS,       struct bch_sb, flags[1],  9, 10);
 965 LE64_BITMASK(BCH_SB_ENCRYPTION_TYPE,    struct bch_sb, flags[1], 10, 14);
 966
 967 /*
 968  * Max size of an extent that may require bouncing to read or write
 969  * (checksummed, compressed): 64k
 970  */
 971 LE64_BITMASK(BCH_SB_ENCODED_EXTENT_MAX_BITS,
 972                                         struct bch_sb, flags[1], 14, 20);
 973
 974 LE64_BITMASK(BCH_SB_META_REPLICAS_REQ,  struct bch_sb, flags[1], 20, 24);
 975 LE64_BITMASK(BCH_SB_DATA_REPLICAS_REQ,  struct bch_sb, flags[1], 24, 28);
 976
 977 LE64_BITMASK(BCH_SB_PROMOTE_TARGET,     struct bch_sb, flags[1], 28, 40);
 978 LE64_BITMASK(BCH_SB_FOREGROUND_TARGET,  struct bch_sb, flags[1], 40, 52);
 979 LE64_BITMASK(BCH_SB_BACKGROUND_TARGET,  struct bch_sb, flags[1], 52, 64);
 980
 981 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO,
 982                                         struct bch_sb, flags[2],  0,  4);
 983 LE64_BITMASK(BCH_SB_GC_RESERVE_BYTES,   struct bch_sb, flags[2],  4, 64);
 984
 985 LE64_BITMASK(BCH_SB_ERASURE_CODE,       struct bch_sb, flags[3],  0, 16);
 986 LE64_BITMASK(BCH_SB_METADATA_TARGET,    struct bch_sb, flags[3], 16, 28);
 987 LE64_BITMASK(BCH_SB_SHARD_INUMS,        struct bch_sb, flags[3], 28, 29);
 988 LE64_BITMASK(BCH_SB_INODES_USE_KEY_CACHE,struct bch_sb, flags[3], 29, 30);
 989 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DELAY,struct bch_sb, flags[3], 30, 62);
 990 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DISABLED,struct bch_sb, flags[3], 62, 63);
 991 LE64_BITMASK(BCH_SB_JOURNAL_RECLAIM_DELAY,struct bch_sb, flags[4], 0, 32);
 992 LE64_BITMASK(BCH_SB_JOURNAL_TRANSACTION_NAMES,struct bch_sb, flags[4], 32, 33);
 993 LE64_BITMASK(BCH_SB_NOCOW,              struct bch_sb, flags[4], 33, 34);
 994 LE64_BITMASK(BCH_SB_WRITE_BUFFER_SIZE,  struct bch_sb, flags[4], 34, 54);
 995 LE64_BITMASK(BCH_SB_VERSION_UPGRADE,    struct bch_sb, flags[4], 54, 56);
 996
 997 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_HI,struct bch_sb, flags[4], 56, 60);
 998 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI,
 999                                         struct bch_sb, flags[4], 60, 64);
1000
1001 LE64_BITMASK(BCH_SB_VERSION_UPGRADE_COMPLETE,
1002                                         struct bch_sb, flags[5],  0, 16);
1003
1004 static inline __u64 BCH_SB_COMPRESSION_TYPE(const struct bch_sb *sb)
1005 {
1006         return BCH_SB_COMPRESSION_TYPE_LO(sb) | (BCH_SB_COMPRESSION_TYPE_HI(sb) << 4);
1007 }
1008
1009 static inline void SET_BCH_SB_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1010 {
1011         SET_BCH_SB_COMPRESSION_TYPE_LO(sb, v);
1012         SET_BCH_SB_COMPRESSION_TYPE_HI(sb, v >> 4);
1013 }
1014
1015 static inline __u64 BCH_SB_BACKGROUND_COMPRESSION_TYPE(const struct bch_sb *sb)
1016 {
1017         return BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb) |
1018                 (BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb) << 4);
1019 }
1020
1021 static inline void SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1022 {
1023         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb, v);
1024         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb, v >> 4);
1025 }
1026
1027 /*
1028  * Features:
1029  *
1030  * journal_seq_blacklist_v3:    gates BCH_SB_FIELD_journal_seq_blacklist
1031  * reflink:                     gates KEY_TYPE_reflink
1032  * inline_data:                 gates KEY_TYPE_inline_data
1033  * new_siphash:                 gates BCH_STR_HASH_siphash
1034  * new_extent_overwrite:        gates BTREE_NODE_NEW_EXTENT_OVERWRITE
1035  */
1036 #define BCH_SB_FEATURES()                       \
1037         x(lz4,                          0)      \
1038         x(gzip,                         1)      \
1039         x(zstd,                         2)      \
1040         x(atomic_nlink,                 3)      \
1041         x(ec,                           4)      \
1042         x(journal_seq_blacklist_v3,     5)      \
1043         x(reflink,                      6)      \
1044         x(new_siphash,                  7)      \
1045         x(inline_data,                  8)      \
1046         x(new_extent_overwrite,         9)      \
1047         x(incompressible,               10)     \
1048         x(btree_ptr_v2,                 11)     \
1049         x(extents_above_btree_updates,  12)     \
1050         x(btree_updates_journalled,     13)     \
1051         x(reflink_inline_data,          14)     \
1052         x(new_varint,                   15)     \
1053         x(journal_no_flush,             16)     \
1054         x(alloc_v2,                     17)     \
1055         x(extents_across_btree_nodes,   18)
1056
1057 #define BCH_SB_FEATURES_ALWAYS                          \
1058         ((1ULL << BCH_FEATURE_new_extent_overwrite)|    \
1059          (1ULL << BCH_FEATURE_extents_above_btree_updates)|\
1060          (1ULL << BCH_FEATURE_btree_updates_journalled)|\
1061          (1ULL << BCH_FEATURE_alloc_v2)|\
1062          (1ULL << BCH_FEATURE_extents_across_btree_nodes))
1063
1064 #define BCH_SB_FEATURES_ALL                             \
1065         (BCH_SB_FEATURES_ALWAYS|                        \
1066          (1ULL << BCH_FEATURE_new_siphash)|             \
1067          (1ULL << BCH_FEATURE_btree_ptr_v2)|            \
1068          (1ULL << BCH_FEATURE_new_varint)|              \
1069          (1ULL << BCH_FEATURE_journal_no_flush))
1070
1071 enum bch_sb_feature {
1072 #define x(f, n) BCH_FEATURE_##f,
1073         BCH_SB_FEATURES()
1074 #undef x
1075         BCH_FEATURE_NR,
1076 };
1077
1078 #define BCH_SB_COMPAT()                                 \
1079         x(alloc_info,                           0)      \
1080         x(alloc_metadata,                       1)      \
1081         x(extents_above_btree_updates_done,     2)      \
1082         x(bformat_overflow_done,                3)
1083
1084 enum bch_sb_compat {
1085 #define x(f, n) BCH_COMPAT_##f,
1086         BCH_SB_COMPAT()
1087 #undef x
1088         BCH_COMPAT_NR,
1089 };
1090
1091 /* options: */
1092
1093 #define BCH_VERSION_UPGRADE_OPTS()      \
1094         x(compatible,           0)      \
1095         x(incompatible,         1)      \
1096         x(none,                 2)
1097
1098 enum bch_version_upgrade_opts {
1099 #define x(t, n) BCH_VERSION_UPGRADE_##t = n,
1100         BCH_VERSION_UPGRADE_OPTS()
1101 #undef x
1102 };
1103
1104 #define BCH_REPLICAS_MAX                4U
1105
1106 #define BCH_BKEY_PTRS_MAX               16U
1107
1108 #define BCH_ERROR_ACTIONS()             \
1109         x(continue,             0)      \
1110         x(ro,                   1)      \
1111         x(panic,                2)
1112
1113 enum bch_error_actions {
1114 #define x(t, n) BCH_ON_ERROR_##t = n,
1115         BCH_ERROR_ACTIONS()
1116 #undef x
1117         BCH_ON_ERROR_NR
1118 };
1119
1120 #define BCH_STR_HASH_TYPES()            \
1121         x(crc32c,               0)      \
1122         x(crc64,                1)      \
1123         x(siphash_old,          2)      \
1124         x(siphash,              3)
1125
1126 enum bch_str_hash_type {
1127 #define x(t, n) BCH_STR_HASH_##t = n,
1128         BCH_STR_HASH_TYPES()
1129 #undef x
1130         BCH_STR_HASH_NR
1131 };
1132
1133 #define BCH_STR_HASH_OPTS()             \
1134         x(crc32c,               0)      \
1135         x(crc64,                1)      \
1136         x(siphash,              2)
1137
1138 enum bch_str_hash_opts {
1139 #define x(t, n) BCH_STR_HASH_OPT_##t = n,
1140         BCH_STR_HASH_OPTS()
1141 #undef x
1142         BCH_STR_HASH_OPT_NR
1143 };
1144
1145 #define BCH_CSUM_TYPES()                        \
1146         x(none,                         0)      \
1147         x(crc32c_nonzero,               1)      \
1148         x(crc64_nonzero,                2)      \
1149         x(chacha20_poly1305_80,         3)      \
1150         x(chacha20_poly1305_128,        4)      \
1151         x(crc32c,                       5)      \
1152         x(crc64,                        6)      \
1153         x(xxhash,                       7)
1154
1155 enum bch_csum_type {
1156 #define x(t, n) BCH_CSUM_##t = n,
1157         BCH_CSUM_TYPES()
1158 #undef x
1159         BCH_CSUM_NR
1160 };
1161
1162 static const __maybe_unused unsigned bch_crc_bytes[] = {
1163         [BCH_CSUM_none]                         = 0,
1164         [BCH_CSUM_crc32c_nonzero]               = 4,
1165         [BCH_CSUM_crc32c]                       = 4,
1166         [BCH_CSUM_crc64_nonzero]                = 8,
1167         [BCH_CSUM_crc64]                        = 8,
1168         [BCH_CSUM_xxhash]                       = 8,
1169         [BCH_CSUM_chacha20_poly1305_80]         = 10,
1170         [BCH_CSUM_chacha20_poly1305_128]        = 16,
1171 };
1172
1173 static inline _Bool bch2_csum_type_is_encryption(enum bch_csum_type type)
1174 {
1175         switch (type) {
1176         case BCH_CSUM_chacha20_poly1305_80:
1177         case BCH_CSUM_chacha20_poly1305_128:
1178                 return true;
1179         default:
1180                 return false;
1181         }
1182 }
1183
1184 #define BCH_CSUM_OPTS()                 \
1185         x(none,                 0)      \
1186         x(crc32c,               1)      \
1187         x(crc64,                2)      \
1188         x(xxhash,               3)
1189
1190 enum bch_csum_opts {
1191 #define x(t, n) BCH_CSUM_OPT_##t = n,
1192         BCH_CSUM_OPTS()
1193 #undef x
1194         BCH_CSUM_OPT_NR
1195 };
1196
1197 #define BCH_COMPRESSION_TYPES()         \
1198         x(none,                 0)      \
1199         x(lz4_old,              1)      \
1200         x(gzip,                 2)      \
1201         x(lz4,                  3)      \
1202         x(zstd,                 4)      \
1203         x(incompressible,       5)
1204
1205 enum bch_compression_type {
1206 #define x(t, n) BCH_COMPRESSION_TYPE_##t = n,
1207         BCH_COMPRESSION_TYPES()
1208 #undef x
1209         BCH_COMPRESSION_TYPE_NR
1210 };
1211
1212 #define BCH_COMPRESSION_OPTS()          \
1213         x(none,         0)              \
1214         x(lz4,          1)              \
1215         x(gzip,         2)              \
1216         x(zstd,         3)
1217
1218 enum bch_compression_opts {
1219 #define x(t, n) BCH_COMPRESSION_OPT_##t = n,
1220         BCH_COMPRESSION_OPTS()
1221 #undef x
1222         BCH_COMPRESSION_OPT_NR
1223 };
1224
1225 /*
1226  * Magic numbers
1227  *
1228  * The various other data structures have their own magic numbers, which are
1229  * xored with the first part of the cache set's UUID
1230  */
1231
1232 #define BCACHE_MAGIC                                                    \
1233         UUID_INIT(0xc68573f6, 0x4e1a, 0x45ca,                           \
1234                   0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81)
1235 #define BCHFS_MAGIC                                                     \
1236         UUID_INIT(0xc68573f6, 0x66ce, 0x90a9,                           \
1237                   0xd9, 0x6a, 0x60, 0xcf, 0x80, 0x3d, 0xf7, 0xef)
1238
1239 #define BCACHEFS_STATFS_MAGIC           0xca451a4e
1240
1241 #define JSET_MAGIC              __cpu_to_le64(0x245235c1a3625032ULL)
1242 #define BSET_MAGIC              __cpu_to_le64(0x90135c78b99e07f5ULL)
1243
1244 static inline __le64 __bch2_sb_magic(struct bch_sb *sb)
1245 {
1246         __le64 ret;
1247
1248         memcpy(&ret, &sb->uuid, sizeof(ret));
1249         return ret;
1250 }
1251
1252 static inline __u64 __jset_magic(struct bch_sb *sb)
1253 {
1254         return __le64_to_cpu(__bch2_sb_magic(sb) ^ JSET_MAGIC);
1255 }
1256
1257 static inline __u64 __bset_magic(struct bch_sb *sb)
1258 {
1259         return __le64_to_cpu(__bch2_sb_magic(sb) ^ BSET_MAGIC);
1260 }
1261
1262 /* Journal */
1263
1264 #define JSET_KEYS_U64s  (sizeof(struct jset_entry) / sizeof(__u64))
1265
1266 #define BCH_JSET_ENTRY_TYPES()                  \
1267         x(btree_keys,           0)              \
1268         x(btree_root,           1)              \
1269         x(prio_ptrs,            2)              \
1270         x(blacklist,            3)              \
1271         x(blacklist_v2,         4)              \
1272         x(usage,                5)              \
1273         x(data_usage,           6)              \
1274         x(clock,                7)              \
1275         x(dev_usage,            8)              \
1276         x(log,                  9)              \
1277         x(overwrite,            10)             \
1278         x(write_buffer_keys,    11)             \
1279         x(datetime,             12)
1280
1281 enum {
1282 #define x(f, nr)        BCH_JSET_ENTRY_##f      = nr,
1283         BCH_JSET_ENTRY_TYPES()
1284 #undef x
1285         BCH_JSET_ENTRY_NR
1286 };
1287
1288 static inline bool jset_entry_is_key(struct jset_entry *e)
1289 {
1290         switch (e->type) {
1291         case BCH_JSET_ENTRY_btree_keys:
1292         case BCH_JSET_ENTRY_btree_root:
1293         case BCH_JSET_ENTRY_overwrite:
1294         case BCH_JSET_ENTRY_write_buffer_keys:
1295                 return true;
1296         }
1297
1298         return false;
1299 }
1300
1301 /*
1302  * Journal sequence numbers can be blacklisted: bsets record the max sequence
1303  * number of all the journal entries they contain updates for, so that on
1304  * recovery we can ignore those bsets that contain index updates newer that what
1305  * made it into the journal.
1306  *
1307  * This means that we can't reuse that journal_seq - we have to skip it, and
1308  * then record that we skipped it so that the next time we crash and recover we
1309  * don't think there was a missing journal entry.
1310  */
1311 struct jset_entry_blacklist {
1312         struct jset_entry       entry;
1313         __le64                  seq;
1314 };
1315
1316 struct jset_entry_blacklist_v2 {
1317         struct jset_entry       entry;
1318         __le64                  start;
1319         __le64                  end;
1320 };
1321
1322 #define BCH_FS_USAGE_TYPES()                    \
1323         x(reserved,             0)              \
1324         x(inodes,               1)              \
1325         x(key_version,          2)
1326
1327 enum {
1328 #define x(f, nr)        BCH_FS_USAGE_##f        = nr,
1329         BCH_FS_USAGE_TYPES()
1330 #undef x
1331         BCH_FS_USAGE_NR
1332 };
1333
1334 struct jset_entry_usage {
1335         struct jset_entry       entry;
1336         __le64                  v;
1337 } __packed;
1338
1339 struct jset_entry_data_usage {
1340         struct jset_entry       entry;
1341         __le64                  v;
1342         struct bch_replicas_entry_v1 r;
1343 } __packed;
1344
1345 struct jset_entry_clock {
1346         struct jset_entry       entry;
1347         __u8                    rw;
1348         __u8                    pad[7];
1349         __le64                  time;
1350 } __packed;
1351
1352 struct jset_entry_dev_usage_type {
1353         __le64                  buckets;
1354         __le64                  sectors;
1355         __le64                  fragmented;
1356 } __packed;
1357
1358 struct jset_entry_dev_usage {
1359         struct jset_entry       entry;
1360         __le32                  dev;
1361         __u32                   pad;
1362
1363         __le64                  _buckets_ec;            /* No longer used */
1364         __le64                  _buckets_unavailable;   /* No longer used */
1365
1366         struct jset_entry_dev_usage_type d[];
1367 };
1368
1369 static inline unsigned jset_entry_dev_usage_nr_types(struct jset_entry_dev_usage *u)
1370 {
1371         return (vstruct_bytes(&u->entry) - sizeof(struct jset_entry_dev_usage)) /
1372                 sizeof(struct jset_entry_dev_usage_type);
1373 }
1374
1375 struct jset_entry_log {
1376         struct jset_entry       entry;
1377         u8                      d[];
1378 } __packed __aligned(8);
1379
1380 struct jset_entry_datetime {
1381         struct jset_entry       entry;
1382         __le64                  seconds;
1383 } __packed __aligned(8);
1384
1385 /*
1386  * On disk format for a journal entry:
1387  * seq is monotonically increasing; every journal entry has its own unique
1388  * sequence number.
1389  *
1390  * last_seq is the oldest journal entry that still has keys the btree hasn't
1391  * flushed to disk yet.
1392  *
1393  * version is for on disk format changes.
1394  */
1395 struct jset {
1396         struct bch_csum         csum;
1397
1398         __le64                  magic;
1399         __le64                  seq;
1400         __le32                  version;
1401         __le32                  flags;
1402
1403         __le32                  u64s; /* size of d[] in u64s */
1404
1405         __u8                    encrypted_start[0];
1406
1407         __le16                  _read_clock; /* no longer used */
1408         __le16                  _write_clock;
1409
1410         /* Sequence number of oldest dirty journal entry */
1411         __le64                  last_seq;
1412
1413
1414         struct jset_entry       start[0];
1415         __u64                   _data[];
1416 } __packed __aligned(8);
1417
1418 LE32_BITMASK(JSET_CSUM_TYPE,    struct jset, flags, 0, 4);
1419 LE32_BITMASK(JSET_BIG_ENDIAN,   struct jset, flags, 4, 5);
1420 LE32_BITMASK(JSET_NO_FLUSH,     struct jset, flags, 5, 6);
1421
1422 #define BCH_JOURNAL_BUCKETS_MIN         8
1423
1424 /* Btree: */
1425
1426 enum btree_id_flags {
1427         BTREE_ID_EXTENTS        = BIT(0),
1428         BTREE_ID_SNAPSHOTS      = BIT(1),
1429         BTREE_ID_SNAPSHOT_FIELD = BIT(2),
1430         BTREE_ID_DATA           = BIT(3),
1431 };
1432
1433 #define BCH_BTREE_IDS()                                                         \
1434         x(extents,              0,      BTREE_ID_EXTENTS|BTREE_ID_SNAPSHOTS|BTREE_ID_DATA,\
1435           BIT_ULL(KEY_TYPE_whiteout)|                                           \
1436           BIT_ULL(KEY_TYPE_error)|                                              \
1437           BIT_ULL(KEY_TYPE_cookie)|                                             \
1438           BIT_ULL(KEY_TYPE_extent)|                                             \
1439           BIT_ULL(KEY_TYPE_reservation)|                                        \
1440           BIT_ULL(KEY_TYPE_reflink_p)|                                          \
1441           BIT_ULL(KEY_TYPE_inline_data))                                        \
1442         x(inodes,               1,      BTREE_ID_SNAPSHOTS,                     \
1443           BIT_ULL(KEY_TYPE_whiteout)|                                           \
1444           BIT_ULL(KEY_TYPE_inode)|                                              \
1445           BIT_ULL(KEY_TYPE_inode_v2)|                                           \
1446           BIT_ULL(KEY_TYPE_inode_v3)|                                           \
1447           BIT_ULL(KEY_TYPE_inode_generation))                                   \
1448         x(dirents,              2,      BTREE_ID_SNAPSHOTS,                     \
1449           BIT_ULL(KEY_TYPE_whiteout)|                                           \
1450           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
1451           BIT_ULL(KEY_TYPE_dirent))                                             \
1452         x(xattrs,               3,      BTREE_ID_SNAPSHOTS,                     \
1453           BIT_ULL(KEY_TYPE_whiteout)|                                           \
1454           BIT_ULL(KEY_TYPE_cookie)|                                             \
1455           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
1456           BIT_ULL(KEY_TYPE_xattr))                                              \
1457         x(alloc,                4,      0,                                      \
1458           BIT_ULL(KEY_TYPE_alloc)|                                              \
1459           BIT_ULL(KEY_TYPE_alloc_v2)|                                           \
1460           BIT_ULL(KEY_TYPE_alloc_v3)|                                           \
1461           BIT_ULL(KEY_TYPE_alloc_v4))                                           \
1462         x(quotas,               5,      0,                                      \
1463           BIT_ULL(KEY_TYPE_quota))                                              \
1464         x(stripes,              6,      0,                                      \
1465           BIT_ULL(KEY_TYPE_stripe))                                             \
1466         x(reflink,              7,      BTREE_ID_EXTENTS|BTREE_ID_DATA,         \
1467           BIT_ULL(KEY_TYPE_reflink_v)|                                          \
1468           BIT_ULL(KEY_TYPE_indirect_inline_data))                               \
1469         x(subvolumes,           8,      0,                                      \
1470           BIT_ULL(KEY_TYPE_subvolume))                                          \
1471         x(snapshots,            9,      0,                                      \
1472           BIT_ULL(KEY_TYPE_snapshot))                                           \
1473         x(lru,                  10,     0,                                      \
1474           BIT_ULL(KEY_TYPE_set))                                                \
1475         x(freespace,            11,     BTREE_ID_EXTENTS,                       \
1476           BIT_ULL(KEY_TYPE_set))                                                \
1477         x(need_discard,         12,     0,                                      \
1478           BIT_ULL(KEY_TYPE_set))                                                \
1479         x(backpointers,         13,     0,                                      \
1480           BIT_ULL(KEY_TYPE_backpointer))                                        \
1481         x(bucket_gens,          14,     0,                                      \
1482           BIT_ULL(KEY_TYPE_bucket_gens))                                        \
1483         x(snapshot_trees,       15,     0,                                      \
1484           BIT_ULL(KEY_TYPE_snapshot_tree))                                      \
1485         x(deleted_inodes,       16,     BTREE_ID_SNAPSHOT_FIELD,                \
1486           BIT_ULL(KEY_TYPE_set))                                                \
1487         x(logged_ops,           17,     0,                                      \
1488           BIT_ULL(KEY_TYPE_logged_op_truncate)|                                 \
1489           BIT_ULL(KEY_TYPE_logged_op_finsert))                                  \
1490         x(rebalance_work,       18,     BTREE_ID_SNAPSHOT_FIELD,                \
1491           BIT_ULL(KEY_TYPE_set)|BIT_ULL(KEY_TYPE_cookie))
1492
1493 enum btree_id {
1494 #define x(name, nr, ...) BTREE_ID_##name = nr,
1495         BCH_BTREE_IDS()
1496 #undef x
1497         BTREE_ID_NR
1498 };
1499
1500 #define BTREE_MAX_DEPTH         4U
1501
1502 /* Btree nodes */
1503
1504 /*
1505  * Btree nodes
1506  *
1507  * On disk a btree node is a list/log of these; within each set the keys are
1508  * sorted
1509  */
1510 struct bset {
1511         __le64                  seq;
1512
1513         /*
1514          * Highest journal entry this bset contains keys for.
1515          * If on recovery we don't see that journal entry, this bset is ignored:
1516          * this allows us to preserve the order of all index updates after a
1517          * crash, since the journal records a total order of all index updates
1518          * and anything that didn't make it to the journal doesn't get used.
1519          */
1520         __le64                  journal_seq;
1521
1522         __le32                  flags;
1523         __le16                  version;
1524         __le16                  u64s; /* count of d[] in u64s */
1525
1526         struct bkey_packed      start[0];
1527         __u64                   _data[];
1528 } __packed __aligned(8);
1529
1530 LE32_BITMASK(BSET_CSUM_TYPE,    struct bset, flags, 0, 4);
1531
1532 LE32_BITMASK(BSET_BIG_ENDIAN,   struct bset, flags, 4, 5);
1533 LE32_BITMASK(BSET_SEPARATE_WHITEOUTS,
1534                                 struct bset, flags, 5, 6);
1535
1536 /* Sector offset within the btree node: */
1537 LE32_BITMASK(BSET_OFFSET,       struct bset, flags, 16, 32);
1538
1539 struct btree_node {
1540         struct bch_csum         csum;
1541         __le64                  magic;
1542
1543         /* this flags field is encrypted, unlike bset->flags: */
1544         __le64                  flags;
1545
1546         /* Closed interval: */
1547         struct bpos             min_key;
1548         struct bpos             max_key;
1549         struct bch_extent_ptr   _ptr; /* not used anymore */
1550         struct bkey_format      format;
1551
1552         union {
1553         struct bset             keys;
1554         struct {
1555                 __u8            pad[22];
1556                 __le16          u64s;
1557                 __u64           _data[0];
1558
1559         };
1560         };
1561 } __packed __aligned(8);
1562
1563 LE64_BITMASK(BTREE_NODE_ID_LO,  struct btree_node, flags,  0,  4);
1564 LE64_BITMASK(BTREE_NODE_LEVEL,  struct btree_node, flags,  4,  8);
1565 LE64_BITMASK(BTREE_NODE_NEW_EXTENT_OVERWRITE,
1566                                 struct btree_node, flags,  8,  9);
1567 LE64_BITMASK(BTREE_NODE_ID_HI,  struct btree_node, flags,  9, 25);
1568 /* 25-32 unused */
1569 LE64_BITMASK(BTREE_NODE_SEQ,    struct btree_node, flags, 32, 64);
1570
1571 static inline __u64 BTREE_NODE_ID(struct btree_node *n)
1572 {
1573         return BTREE_NODE_ID_LO(n) | (BTREE_NODE_ID_HI(n) << 4);
1574 }
1575
1576 static inline void SET_BTREE_NODE_ID(struct btree_node *n, __u64 v)
1577 {
1578         SET_BTREE_NODE_ID_LO(n, v);
1579         SET_BTREE_NODE_ID_HI(n, v >> 4);
1580 }
1581
1582 struct btree_node_entry {
1583         struct bch_csum         csum;
1584
1585         union {
1586         struct bset             keys;
1587         struct {
1588                 __u8            pad[22];
1589                 __le16          u64s;
1590                 __u64           _data[0];
1591         };
1592         };
1593 } __packed __aligned(8);
1594
1595 #endif /* _BCACHEFS_FORMAT_H */