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
 226 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 227 /*
 228  * The big-endian version of bkey can't be compiled by rustc with the "aligned"
 229  * attr since it doesn't allow types to have both "packed" and "aligned" attrs.
 230  * So for Rust compatibility, don't include this. It can be included in the LE
 231  * version because the "packed" attr is redundant in that case.
 232  *
 233  * History: (quoting Kent)
 234  *
 235  * Specifically, when i was designing bkey, I wanted the header to be no
 236  * bigger than necessary so that bkey_packed could use the rest. That means that
 237  * decently offten extent keys will fit into only 8 bytes, instead of spilling over
 238  * to 16.
 239  *
 240  * But packed_bkey treats the part after the header - the packed section -
 241  * as a single multi word, variable length integer. And bkey, the unpacked
 242  * version, is just a special case version of a bkey_packed; all the packed
 243  * bkey code will work on keys in any packed format, the in-memory
 244  * representation of an unpacked key also is just one type of packed key...
 245  *
 246  * So that constrains the key part of a bkig endian bkey to start right
 247  * after the header.
 248  *
 249  * If we ever do a bkey_v2 and need to expand the hedaer by another byte for
 250  * some reason - that will clean up this wart.
 251  */
 252 __aligned(8)
 253 #endif
 254 ;
 255
 256 struct bkey_packed {
 257         __u64           _data[0];
 258
 259         /* Size of combined key and value, in u64s */
 260         __u8            u64s;
 261
 262         /* Format of key (0 for format local to btree node) */
 263
 264         /*
 265          * XXX: next incompat on disk format change, switch format and
 266          * needs_whiteout - bkey_packed() will be cheaper if format is the high
 267          * bits of the bitfield
 268          */
 269 #if defined(__LITTLE_ENDIAN_BITFIELD)
 270         __u8            format:7,
 271                         needs_whiteout:1;
 272 #elif defined (__BIG_ENDIAN_BITFIELD)
 273         __u8            needs_whiteout:1,
 274                         format:7;
 275 #endif
 276
 277         /* Type of the value */
 278         __u8            type;
 279         __u8            key_start[0];
 280
 281         /*
 282          * We copy bkeys with struct assignment in various places, and while
 283          * that shouldn't be done with packed bkeys we can't disallow it in C,
 284          * and it's legal to cast a bkey to a bkey_packed  - so padding it out
 285          * to the same size as struct bkey should hopefully be safest.
 286          */
 287         __u8            pad[sizeof(struct bkey) - 3];
 288 } __packed __aligned(8);
 289
 290 typedef struct {
 291         __le64                  lo;
 292         __le64                  hi;
 293 } bch_le128;
 294
 295 #define BKEY_U64s                       (sizeof(struct bkey) / sizeof(__u64))
 296 #define BKEY_U64s_MAX                   U8_MAX
 297 #define BKEY_VAL_U64s_MAX               (BKEY_U64s_MAX - BKEY_U64s)
 298
 299 #define KEY_PACKED_BITS_START           24
 300
 301 #define KEY_FORMAT_LOCAL_BTREE          0
 302 #define KEY_FORMAT_CURRENT              1
 303
 304 enum bch_bkey_fields {
 305         BKEY_FIELD_INODE,
 306         BKEY_FIELD_OFFSET,
 307         BKEY_FIELD_SNAPSHOT,
 308         BKEY_FIELD_SIZE,
 309         BKEY_FIELD_VERSION_HI,
 310         BKEY_FIELD_VERSION_LO,
 311         BKEY_NR_FIELDS,
 312 };
 313
 314 #define bkey_format_field(name, field)                                  \
 315         [BKEY_FIELD_##name] = (sizeof(((struct bkey *) NULL)->field) * 8)
 316
 317 #define BKEY_FORMAT_CURRENT                                             \
 318 ((struct bkey_format) {                                                 \
 319         .key_u64s       = BKEY_U64s,                                    \
 320         .nr_fields      = BKEY_NR_FIELDS,                               \
 321         .bits_per_field = {                                             \
 322                 bkey_format_field(INODE,        p.inode),               \
 323                 bkey_format_field(OFFSET,       p.offset),              \
 324                 bkey_format_field(SNAPSHOT,     p.snapshot),            \
 325                 bkey_format_field(SIZE,         size),                  \
 326                 bkey_format_field(VERSION_HI,   version.hi),            \
 327                 bkey_format_field(VERSION_LO,   version.lo),            \
 328         },                                                              \
 329 })
 330
 331 /* bkey with inline value */
 332 struct bkey_i {
 333         __u64                   _data[0];
 334
 335         struct bkey     k;
 336         struct bch_val  v;
 337 };
 338
 339 #define POS_KEY(_pos)                                                   \
 340 ((struct bkey) {                                                        \
 341         .u64s           = BKEY_U64s,                                    \
 342         .format         = KEY_FORMAT_CURRENT,                           \
 343         .p              = _pos,                                         \
 344 })
 345
 346 #define KEY(_inode, _offset, _size)                                     \
 347 ((struct bkey) {                                                        \
 348         .u64s           = BKEY_U64s,                                    \
 349         .format         = KEY_FORMAT_CURRENT,                           \
 350         .p              = POS(_inode, _offset),                         \
 351         .size           = _size,                                        \
 352 })
 353
 354 static inline void bkey_init(struct bkey *k)
 355 {
 356         *k = KEY(0, 0, 0);
 357 }
 358
 359 #define bkey_bytes(_k)          ((_k)->u64s * sizeof(__u64))
 360
 361 #define __BKEY_PADDED(key, pad)                                 \
 362         struct bkey_i key; __u64 key ## _pad[pad]
 363
 364 /*
 365  * - DELETED keys are used internally to mark keys that should be ignored but
 366  *   override keys in composition order.  Their version number is ignored.
 367  *
 368  * - DISCARDED keys indicate that the data is all 0s because it has been
 369  *   discarded. DISCARDs may have a version; if the version is nonzero the key
 370  *   will be persistent, otherwise the key will be dropped whenever the btree
 371  *   node is rewritten (like DELETED keys).
 372  *
 373  * - ERROR: any read of the data returns a read error, as the data was lost due
 374  *   to a failing device. Like DISCARDED keys, they can be removed (overridden)
 375  *   by new writes or cluster-wide GC. Node repair can also overwrite them with
 376  *   the same or a more recent version number, but not with an older version
 377  *   number.
 378  *
 379  * - WHITEOUT: for hash table btrees
 380  */
 381 #define BCH_BKEY_TYPES()                                \
 382         x(deleted,              0)                      \
 383         x(whiteout,             1)                      \
 384         x(error,                2)                      \
 385         x(cookie,               3)                      \
 386         x(hash_whiteout,        4)                      \
 387         x(btree_ptr,            5)                      \
 388         x(extent,               6)                      \
 389         x(reservation,          7)                      \
 390         x(inode,                8)                      \
 391         x(inode_generation,     9)                      \
 392         x(dirent,               10)                     \
 393         x(xattr,                11)                     \
 394         x(alloc,                12)                     \
 395         x(quota,                13)                     \
 396         x(stripe,               14)                     \
 397         x(reflink_p,            15)                     \
 398         x(reflink_v,            16)                     \
 399         x(inline_data,          17)                     \
 400         x(btree_ptr_v2,         18)                     \
 401         x(indirect_inline_data, 19)                     \
 402         x(alloc_v2,             20)                     \
 403         x(subvolume,            21)                     \
 404         x(snapshot,             22)                     \
 405         x(inode_v2,             23)                     \
 406         x(alloc_v3,             24)                     \
 407         x(set,                  25)                     \
 408         x(lru,                  26)                     \
 409         x(alloc_v4,             27)                     \
 410         x(backpointer,          28)                     \
 411         x(inode_v3,             29)                     \
 412         x(bucket_gens,          30)                     \
 413         x(snapshot_tree,        31)                     \
 414         x(logged_op_truncate,   32)                     \
 415         x(logged_op_finsert,    33)
 416
 417 enum bch_bkey_type {
 418 #define x(name, nr) KEY_TYPE_##name     = nr,
 419         BCH_BKEY_TYPES()
 420 #undef x
 421         KEY_TYPE_MAX,
 422 };
 423
 424 struct bch_deleted {
 425         struct bch_val          v;
 426 };
 427
 428 struct bch_whiteout {
 429         struct bch_val          v;
 430 };
 431
 432 struct bch_error {
 433         struct bch_val          v;
 434 };
 435
 436 struct bch_cookie {
 437         struct bch_val          v;
 438         __le64                  cookie;
 439 };
 440
 441 struct bch_hash_whiteout {
 442         struct bch_val          v;
 443 };
 444
 445 struct bch_set {
 446         struct bch_val          v;
 447 };
 448
 449 /* 128 bits, sufficient for cryptographic MACs: */
 450 struct bch_csum {
 451         __le64                  lo;
 452         __le64                  hi;
 453 } __packed __aligned(8);
 454
 455 struct bch_backpointer {
 456         struct bch_val          v;
 457         __u8                    btree_id;
 458         __u8                    level;
 459         __u8                    data_type;
 460         __u64                   bucket_offset:40;
 461         __u32                   bucket_len;
 462         struct bpos             pos;
 463 } __packed __aligned(8);
 464
 465 /* LRU btree: */
 466
 467 struct bch_lru {
 468         struct bch_val          v;
 469         __le64                  idx;
 470 } __packed __aligned(8);
 471
 472 #define LRU_ID_STRIPES          (1U << 16)
 473
 474 /* Optional/variable size superblock sections: */
 475
 476 struct bch_sb_field {
 477         __u64                   _data[0];
 478         __le32                  u64s;
 479         __le32                  type;
 480 };
 481
 482 #define BCH_SB_FIELDS()                         \
 483         x(journal,                      0)      \
 484         x(members_v1,                   1)      \
 485         x(crypt,                        2)      \
 486         x(replicas_v0,                  3)      \
 487         x(quota,                        4)      \
 488         x(disk_groups,                  5)      \
 489         x(clean,                        6)      \
 490         x(replicas,                     7)      \
 491         x(journal_seq_blacklist,        8)      \
 492         x(journal_v2,                   9)      \
 493         x(counters,                     10)     \
 494         x(members_v2,                   11)     \
 495         x(errors,                       12)     \
 496         x(ext,                          13)     \
 497         x(downgrade,                    14)
 498
 499 #include "alloc_background_format.h"
 500 #include "extents_format.h"
 501 #include "reflink_format.h"
 502 #include "ec_format.h"
 503 #include "inode_format.h"
 504 #include "dirent_format.h"
 505 #include "xattr_format.h"
 506 #include "quota_format.h"
 507 #include "logged_ops_format.h"
 508 #include "snapshot_format.h"
 509 #include "subvolume_format.h"
 510 #include "sb-counters_format.h"
 511
 512 enum bch_sb_field_type {
 513 #define x(f, nr)        BCH_SB_FIELD_##f = nr,
 514         BCH_SB_FIELDS()
 515 #undef x
 516         BCH_SB_FIELD_NR
 517 };
 518
 519 /*
 520  * Most superblock fields are replicated in all device's superblocks - a few are
 521  * not:
 522  */
 523 #define BCH_SINGLE_DEVICE_SB_FIELDS             \
 524         ((1U << BCH_SB_FIELD_journal)|          \
 525          (1U << BCH_SB_FIELD_journal_v2))
 526
 527 /* BCH_SB_FIELD_journal: */
 528
 529 struct bch_sb_field_journal {
 530         struct bch_sb_field     field;
 531         __le64                  buckets[];
 532 };
 533
 534 struct bch_sb_field_journal_v2 {
 535         struct bch_sb_field     field;
 536
 537         struct bch_sb_field_journal_v2_entry {
 538                 __le64          start;
 539                 __le64          nr;
 540         }                       d[];
 541 };
 542
 543 /* BCH_SB_FIELD_members_v1: */
 544
 545 #define BCH_MIN_NR_NBUCKETS     (1 << 6)
 546
 547 #define BCH_IOPS_MEASUREMENTS()                 \
 548         x(seqread,      0)                      \
 549         x(seqwrite,     1)                      \
 550         x(randread,     2)                      \
 551         x(randwrite,    3)
 552
 553 enum bch_iops_measurement {
 554 #define x(t, n) BCH_IOPS_##t = n,
 555         BCH_IOPS_MEASUREMENTS()
 556 #undef x
 557         BCH_IOPS_NR
 558 };
 559
 560 #define BCH_MEMBER_ERROR_TYPES()                \
 561         x(read,         0)                      \
 562         x(write,        1)                      \
 563         x(checksum,     2)
 564
 565 enum bch_member_error_type {
 566 #define x(t, n) BCH_MEMBER_ERROR_##t = n,
 567         BCH_MEMBER_ERROR_TYPES()
 568 #undef x
 569         BCH_MEMBER_ERROR_NR
 570 };
 571
 572 struct bch_member {
 573         __uuid_t                uuid;
 574         __le64                  nbuckets;       /* device size */
 575         __le16                  first_bucket;   /* index of first bucket used */
 576         __le16                  bucket_size;    /* sectors */
 577         __le32                  pad;
 578         __le64                  last_mount;     /* time_t */
 579
 580         __le64                  flags;
 581         __le32                  iops[4];
 582         __le64                  errors[BCH_MEMBER_ERROR_NR];
 583         __le64                  errors_at_reset[BCH_MEMBER_ERROR_NR];
 584         __le64                  errors_reset_time;
 585         __le64                  seq;
 586 };
 587
 588 #define BCH_MEMBER_V1_BYTES     56
 589
 590 LE64_BITMASK(BCH_MEMBER_STATE,          struct bch_member, flags,  0,  4)
 591 /* 4-14 unused, was TIER, HAS_(META)DATA, REPLACEMENT */
 592 LE64_BITMASK(BCH_MEMBER_DISCARD,        struct bch_member, flags, 14, 15)
 593 LE64_BITMASK(BCH_MEMBER_DATA_ALLOWED,   struct bch_member, flags, 15, 20)
 594 LE64_BITMASK(BCH_MEMBER_GROUP,          struct bch_member, flags, 20, 28)
 595 LE64_BITMASK(BCH_MEMBER_DURABILITY,     struct bch_member, flags, 28, 30)
 596 LE64_BITMASK(BCH_MEMBER_FREESPACE_INITIALIZED,
 597                                         struct bch_member, flags, 30, 31)
 598
 599 #if 0
 600 LE64_BITMASK(BCH_MEMBER_NR_READ_ERRORS, struct bch_member, flags[1], 0,  20);
 601 LE64_BITMASK(BCH_MEMBER_NR_WRITE_ERRORS,struct bch_member, flags[1], 20, 40);
 602 #endif
 603
 604 #define BCH_MEMBER_STATES()                     \
 605         x(rw,           0)                      \
 606         x(ro,           1)                      \
 607         x(failed,       2)                      \
 608         x(spare,        3)
 609
 610 enum bch_member_state {
 611 #define x(t, n) BCH_MEMBER_STATE_##t = n,
 612         BCH_MEMBER_STATES()
 613 #undef x
 614         BCH_MEMBER_STATE_NR
 615 };
 616
 617 struct bch_sb_field_members_v1 {
 618         struct bch_sb_field     field;
 619         struct bch_member       _members[]; //Members are now variable size
 620 };
 621
 622 struct bch_sb_field_members_v2 {
 623         struct bch_sb_field     field;
 624         __le16                  member_bytes; //size of single member entry
 625         u8                      pad[6];
 626         struct bch_member       _members[];
 627 };
 628
 629 /* BCH_SB_FIELD_crypt: */
 630
 631 struct nonce {
 632         __le32                  d[4];
 633 };
 634
 635 struct bch_key {
 636         __le64                  key[4];
 637 };
 638
 639 #define BCH_KEY_MAGIC                                   \
 640         (((__u64) 'b' <<  0)|((__u64) 'c' <<  8)|               \
 641          ((__u64) 'h' << 16)|((__u64) '*' << 24)|               \
 642          ((__u64) '*' << 32)|((__u64) 'k' << 40)|               \
 643          ((__u64) 'e' << 48)|((__u64) 'y' << 56))
 644
 645 struct bch_encrypted_key {
 646         __le64                  magic;
 647         struct bch_key          key;
 648 };
 649
 650 /*
 651  * If this field is present in the superblock, it stores an encryption key which
 652  * is used encrypt all other data/metadata. The key will normally be encrypted
 653  * with the key userspace provides, but if encryption has been turned off we'll
 654  * just store the master key unencrypted in the superblock so we can access the
 655  * previously encrypted data.
 656  */
 657 struct bch_sb_field_crypt {
 658         struct bch_sb_field     field;
 659
 660         __le64                  flags;
 661         __le64                  kdf_flags;
 662         struct bch_encrypted_key key;
 663 };
 664
 665 LE64_BITMASK(BCH_CRYPT_KDF_TYPE,        struct bch_sb_field_crypt, flags, 0, 4);
 666
 667 enum bch_kdf_types {
 668         BCH_KDF_SCRYPT          = 0,
 669         BCH_KDF_NR              = 1,
 670 };
 671
 672 /* stored as base 2 log of scrypt params: */
 673 LE64_BITMASK(BCH_KDF_SCRYPT_N,  struct bch_sb_field_crypt, kdf_flags,  0, 16);
 674 LE64_BITMASK(BCH_KDF_SCRYPT_R,  struct bch_sb_field_crypt, kdf_flags, 16, 32);
 675 LE64_BITMASK(BCH_KDF_SCRYPT_P,  struct bch_sb_field_crypt, kdf_flags, 32, 48);
 676
 677 /* BCH_SB_FIELD_replicas: */
 678
 679 #define BCH_DATA_TYPES()                \
 680         x(free,         0)              \
 681         x(sb,           1)              \
 682         x(journal,      2)              \
 683         x(btree,        3)              \
 684         x(user,         4)              \
 685         x(cached,       5)              \
 686         x(parity,       6)              \
 687         x(stripe,       7)              \
 688         x(need_gc_gens, 8)              \
 689         x(need_discard, 9)
 690
 691 enum bch_data_type {
 692 #define x(t, n) BCH_DATA_##t,
 693         BCH_DATA_TYPES()
 694 #undef x
 695         BCH_DATA_NR
 696 };
 697
 698 static inline bool data_type_is_empty(enum bch_data_type type)
 699 {
 700         switch (type) {
 701         case BCH_DATA_free:
 702         case BCH_DATA_need_gc_gens:
 703         case BCH_DATA_need_discard:
 704                 return true;
 705         default:
 706                 return false;
 707         }
 708 }
 709
 710 static inline bool data_type_is_hidden(enum bch_data_type type)
 711 {
 712         switch (type) {
 713         case BCH_DATA_sb:
 714         case BCH_DATA_journal:
 715                 return true;
 716         default:
 717                 return false;
 718         }
 719 }
 720
 721 struct bch_replicas_entry_v0 {
 722         __u8                    data_type;
 723         __u8                    nr_devs;
 724         __u8                    devs[];
 725 } __packed;
 726
 727 struct bch_sb_field_replicas_v0 {
 728         struct bch_sb_field     field;
 729         struct bch_replicas_entry_v0 entries[];
 730 } __packed __aligned(8);
 731
 732 struct bch_replicas_entry_v1 {
 733         __u8                    data_type;
 734         __u8                    nr_devs;
 735         __u8                    nr_required;
 736         __u8                    devs[];
 737 } __packed;
 738
 739 #define replicas_entry_bytes(_i)                                        \
 740         (offsetof(typeof(*(_i)), devs) + (_i)->nr_devs)
 741
 742 struct bch_sb_field_replicas {
 743         struct bch_sb_field     field;
 744         struct bch_replicas_entry_v1 entries[];
 745 } __packed __aligned(8);
 746
 747 /* BCH_SB_FIELD_disk_groups: */
 748
 749 #define BCH_SB_LABEL_SIZE               32
 750
 751 struct bch_disk_group {
 752         __u8                    label[BCH_SB_LABEL_SIZE];
 753         __le64                  flags[2];
 754 } __packed __aligned(8);
 755
 756 LE64_BITMASK(BCH_GROUP_DELETED,         struct bch_disk_group, flags[0], 0,  1)
 757 LE64_BITMASK(BCH_GROUP_DATA_ALLOWED,    struct bch_disk_group, flags[0], 1,  6)
 758 LE64_BITMASK(BCH_GROUP_PARENT,          struct bch_disk_group, flags[0], 6, 24)
 759
 760 struct bch_sb_field_disk_groups {
 761         struct bch_sb_field     field;
 762         struct bch_disk_group   entries[];
 763 } __packed __aligned(8);
 764
 765 /*
 766  * On clean shutdown, store btree roots and current journal sequence number in
 767  * the superblock:
 768  */
 769 struct jset_entry {
 770         __le16                  u64s;
 771         __u8                    btree_id;
 772         __u8                    level;
 773         __u8                    type; /* designates what this jset holds */
 774         __u8                    pad[3];
 775
 776         struct bkey_i           start[0];
 777         __u64                   _data[];
 778 };
 779
 780 struct bch_sb_field_clean {
 781         struct bch_sb_field     field;
 782
 783         __le32                  flags;
 784         __le16                  _read_clock; /* no longer used */
 785         __le16                  _write_clock;
 786         __le64                  journal_seq;
 787
 788         struct jset_entry       start[0];
 789         __u64                   _data[];
 790 };
 791
 792 struct journal_seq_blacklist_entry {
 793         __le64                  start;
 794         __le64                  end;
 795 };
 796
 797 struct bch_sb_field_journal_seq_blacklist {
 798         struct bch_sb_field     field;
 799         struct journal_seq_blacklist_entry start[];
 800 };
 801
 802 struct bch_sb_field_errors {
 803         struct bch_sb_field     field;
 804         struct bch_sb_field_error_entry {
 805                 __le64          v;
 806                 __le64          last_error_time;
 807         }                       entries[];
 808 };
 809
 810 LE64_BITMASK(BCH_SB_ERROR_ENTRY_ID,     struct bch_sb_field_error_entry, v,  0, 16);
 811 LE64_BITMASK(BCH_SB_ERROR_ENTRY_NR,     struct bch_sb_field_error_entry, v, 16, 64);
 812
 813 struct bch_sb_field_ext {
 814         struct bch_sb_field     field;
 815         __le64                  recovery_passes_required[2];
 816         __le64                  errors_silent[8];
 817 };
 818
 819 struct bch_sb_field_downgrade_entry {
 820         __le16                  version;
 821         __le64                  recovery_passes[2];
 822         __le16                  nr_errors;
 823         __le16                  errors[] __counted_by(nr_errors);
 824 } __packed __aligned(2);
 825
 826 struct bch_sb_field_downgrade {
 827         struct bch_sb_field     field;
 828         struct bch_sb_field_downgrade_entry entries[];
 829 };
 830
 831 /* Superblock: */
 832
 833 /*
 834  * New versioning scheme:
 835  * One common version number for all on disk data structures - superblock, btree
 836  * nodes, journal entries
 837  */
 838 #define BCH_VERSION_MAJOR(_v)           ((__u16) ((_v) >> 10))
 839 #define BCH_VERSION_MINOR(_v)           ((__u16) ((_v) & ~(~0U << 10)))
 840 #define BCH_VERSION(_major, _minor)     (((_major) << 10)|(_minor) << 0)
 841
 842 /*
 843  * field 1:             version name
 844  * field 2:             BCH_VERSION(major, minor)
 845  * field 3:             recovery passess required on upgrade
 846  */
 847 #define BCH_METADATA_VERSIONS()                                         \
 848         x(bkey_renumber,                BCH_VERSION(0, 10))             \
 849         x(inode_btree_change,           BCH_VERSION(0, 11))             \
 850         x(snapshot,                     BCH_VERSION(0, 12))             \
 851         x(inode_backpointers,           BCH_VERSION(0, 13))             \
 852         x(btree_ptr_sectors_written,    BCH_VERSION(0, 14))             \
 853         x(snapshot_2,                   BCH_VERSION(0, 15))             \
 854         x(reflink_p_fix,                BCH_VERSION(0, 16))             \
 855         x(subvol_dirent,                BCH_VERSION(0, 17))             \
 856         x(inode_v2,                     BCH_VERSION(0, 18))             \
 857         x(freespace,                    BCH_VERSION(0, 19))             \
 858         x(alloc_v4,                     BCH_VERSION(0, 20))             \
 859         x(new_data_types,               BCH_VERSION(0, 21))             \
 860         x(backpointers,                 BCH_VERSION(0, 22))             \
 861         x(inode_v3,                     BCH_VERSION(0, 23))             \
 862         x(unwritten_extents,            BCH_VERSION(0, 24))             \
 863         x(bucket_gens,                  BCH_VERSION(0, 25))             \
 864         x(lru_v2,                       BCH_VERSION(0, 26))             \
 865         x(fragmentation_lru,            BCH_VERSION(0, 27))             \
 866         x(no_bps_in_alloc_keys,         BCH_VERSION(0, 28))             \
 867         x(snapshot_trees,               BCH_VERSION(0, 29))             \
 868         x(major_minor,                  BCH_VERSION(1,  0))             \
 869         x(snapshot_skiplists,           BCH_VERSION(1,  1))             \
 870         x(deleted_inodes,               BCH_VERSION(1,  2))             \
 871         x(rebalance_work,               BCH_VERSION(1,  3))             \
 872         x(member_seq,                   BCH_VERSION(1,  4))             \
 873         x(subvolume_fs_parent,          BCH_VERSION(1,  5))             \
 874         x(btree_subvolume_children,     BCH_VERSION(1,  6))
 875
 876 enum bcachefs_metadata_version {
 877         bcachefs_metadata_version_min = 9,
 878 #define x(t, n) bcachefs_metadata_version_##t = n,
 879         BCH_METADATA_VERSIONS()
 880 #undef x
 881         bcachefs_metadata_version_max
 882 };
 883
 884 static const __maybe_unused
 885 unsigned bcachefs_metadata_required_upgrade_below = bcachefs_metadata_version_rebalance_work;
 886
 887 #define bcachefs_metadata_version_current       (bcachefs_metadata_version_max - 1)
 888
 889 #define BCH_SB_SECTOR                   8
 890 #define BCH_SB_MEMBERS_MAX              64 /* XXX kill */
 891
 892 struct bch_sb_layout {
 893         __uuid_t                magic;  /* bcachefs superblock UUID */
 894         __u8                    layout_type;
 895         __u8                    sb_max_size_bits; /* base 2 of 512 byte sectors */
 896         __u8                    nr_superblocks;
 897         __u8                    pad[5];
 898         __le64                  sb_offset[61];
 899 } __packed __aligned(8);
 900
 901 #define BCH_SB_LAYOUT_SECTOR    7
 902
 903 /*
 904  * @offset      - sector where this sb was written
 905  * @version     - on disk format version
 906  * @version_min - Oldest metadata version this filesystem contains; so we can
 907  *                safely drop compatibility code and refuse to mount filesystems
 908  *                we'd need it for
 909  * @magic       - identifies as a bcachefs superblock (BCHFS_MAGIC)
 910  * @seq         - incremented each time superblock is written
 911  * @uuid        - used for generating various magic numbers and identifying
 912  *                member devices, never changes
 913  * @user_uuid   - user visible UUID, may be changed
 914  * @label       - filesystem label
 915  * @seq         - identifies most recent superblock, incremented each time
 916  *                superblock is written
 917  * @features    - enabled incompatible features
 918  */
 919 struct bch_sb {
 920         struct bch_csum         csum;
 921         __le16                  version;
 922         __le16                  version_min;
 923         __le16                  pad[2];
 924         __uuid_t                magic;
 925         __uuid_t                uuid;
 926         __uuid_t                user_uuid;
 927         __u8                    label[BCH_SB_LABEL_SIZE];
 928         __le64                  offset;
 929         __le64                  seq;
 930
 931         __le16                  block_size;
 932         __u8                    dev_idx;
 933         __u8                    nr_devices;
 934         __le32                  u64s;
 935
 936         __le64                  time_base_lo;
 937         __le32                  time_base_hi;
 938         __le32                  time_precision;
 939
 940         __le64                  flags[7];
 941         __le64                  write_time;
 942         __le64                  features[2];
 943         __le64                  compat[2];
 944
 945         struct bch_sb_layout    layout;
 946
 947         struct bch_sb_field     start[0];
 948         __le64                  _data[];
 949 } __packed __aligned(8);
 950
 951 /*
 952  * Flags:
 953  * BCH_SB_INITALIZED    - set on first mount
 954  * BCH_SB_CLEAN         - did we shut down cleanly? Just a hint, doesn't affect
 955  *                        behaviour of mount/recovery path:
 956  * BCH_SB_INODE_32BIT   - limit inode numbers to 32 bits
 957  * BCH_SB_128_BIT_MACS  - 128 bit macs instead of 80
 958  * BCH_SB_ENCRYPTION_TYPE - if nonzero encryption is enabled; overrides
 959  *                         DATA/META_CSUM_TYPE. Also indicates encryption
 960  *                         algorithm in use, if/when we get more than one
 961  */
 962
 963 LE16_BITMASK(BCH_SB_BLOCK_SIZE,         struct bch_sb, block_size, 0, 16);
 964
 965 LE64_BITMASK(BCH_SB_INITIALIZED,        struct bch_sb, flags[0],  0,  1);
 966 LE64_BITMASK(BCH_SB_CLEAN,              struct bch_sb, flags[0],  1,  2);
 967 LE64_BITMASK(BCH_SB_CSUM_TYPE,          struct bch_sb, flags[0],  2,  8);
 968 LE64_BITMASK(BCH_SB_ERROR_ACTION,       struct bch_sb, flags[0],  8, 12);
 969
 970 LE64_BITMASK(BCH_SB_BTREE_NODE_SIZE,    struct bch_sb, flags[0], 12, 28);
 971
 972 LE64_BITMASK(BCH_SB_GC_RESERVE,         struct bch_sb, flags[0], 28, 33);
 973 LE64_BITMASK(BCH_SB_ROOT_RESERVE,       struct bch_sb, flags[0], 33, 40);
 974
 975 LE64_BITMASK(BCH_SB_META_CSUM_TYPE,     struct bch_sb, flags[0], 40, 44);
 976 LE64_BITMASK(BCH_SB_DATA_CSUM_TYPE,     struct bch_sb, flags[0], 44, 48);
 977
 978 LE64_BITMASK(BCH_SB_META_REPLICAS_WANT, struct bch_sb, flags[0], 48, 52);
 979 LE64_BITMASK(BCH_SB_DATA_REPLICAS_WANT, struct bch_sb, flags[0], 52, 56);
 980
 981 LE64_BITMASK(BCH_SB_POSIX_ACL,          struct bch_sb, flags[0], 56, 57);
 982 LE64_BITMASK(BCH_SB_USRQUOTA,           struct bch_sb, flags[0], 57, 58);
 983 LE64_BITMASK(BCH_SB_GRPQUOTA,           struct bch_sb, flags[0], 58, 59);
 984 LE64_BITMASK(BCH_SB_PRJQUOTA,           struct bch_sb, flags[0], 59, 60);
 985
 986 LE64_BITMASK(BCH_SB_HAS_ERRORS,         struct bch_sb, flags[0], 60, 61);
 987 LE64_BITMASK(BCH_SB_HAS_TOPOLOGY_ERRORS,struct bch_sb, flags[0], 61, 62);
 988
 989 LE64_BITMASK(BCH_SB_BIG_ENDIAN,         struct bch_sb, flags[0], 62, 63);
 990
 991 LE64_BITMASK(BCH_SB_STR_HASH_TYPE,      struct bch_sb, flags[1],  0,  4);
 992 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_LO,struct bch_sb, flags[1],  4,  8);
 993 LE64_BITMASK(BCH_SB_INODE_32BIT,        struct bch_sb, flags[1],  8,  9);
 994
 995 LE64_BITMASK(BCH_SB_128_BIT_MACS,       struct bch_sb, flags[1],  9, 10);
 996 LE64_BITMASK(BCH_SB_ENCRYPTION_TYPE,    struct bch_sb, flags[1], 10, 14);
 997
 998 /*
 999  * Max size of an extent that may require bouncing to read or write
1000  * (checksummed, compressed): 64k
1001  */
1002 LE64_BITMASK(BCH_SB_ENCODED_EXTENT_MAX_BITS,
1003                                         struct bch_sb, flags[1], 14, 20);
1004
1005 LE64_BITMASK(BCH_SB_META_REPLICAS_REQ,  struct bch_sb, flags[1], 20, 24);
1006 LE64_BITMASK(BCH_SB_DATA_REPLICAS_REQ,  struct bch_sb, flags[1], 24, 28);
1007
1008 LE64_BITMASK(BCH_SB_PROMOTE_TARGET,     struct bch_sb, flags[1], 28, 40);
1009 LE64_BITMASK(BCH_SB_FOREGROUND_TARGET,  struct bch_sb, flags[1], 40, 52);
1010 LE64_BITMASK(BCH_SB_BACKGROUND_TARGET,  struct bch_sb, flags[1], 52, 64);
1011
1012 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO,
1013                                         struct bch_sb, flags[2],  0,  4);
1014 LE64_BITMASK(BCH_SB_GC_RESERVE_BYTES,   struct bch_sb, flags[2],  4, 64);
1015
1016 LE64_BITMASK(BCH_SB_ERASURE_CODE,       struct bch_sb, flags[3],  0, 16);
1017 LE64_BITMASK(BCH_SB_METADATA_TARGET,    struct bch_sb, flags[3], 16, 28);
1018 LE64_BITMASK(BCH_SB_SHARD_INUMS,        struct bch_sb, flags[3], 28, 29);
1019 LE64_BITMASK(BCH_SB_INODES_USE_KEY_CACHE,struct bch_sb, flags[3], 29, 30);
1020 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DELAY,struct bch_sb, flags[3], 30, 62);
1021 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DISABLED,struct bch_sb, flags[3], 62, 63);
1022 LE64_BITMASK(BCH_SB_JOURNAL_RECLAIM_DELAY,struct bch_sb, flags[4], 0, 32);
1023 LE64_BITMASK(BCH_SB_JOURNAL_TRANSACTION_NAMES,struct bch_sb, flags[4], 32, 33);
1024 LE64_BITMASK(BCH_SB_NOCOW,              struct bch_sb, flags[4], 33, 34);
1025 LE64_BITMASK(BCH_SB_WRITE_BUFFER_SIZE,  struct bch_sb, flags[4], 34, 54);
1026 LE64_BITMASK(BCH_SB_VERSION_UPGRADE,    struct bch_sb, flags[4], 54, 56);
1027
1028 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_HI,struct bch_sb, flags[4], 56, 60);
1029 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI,
1030                                         struct bch_sb, flags[4], 60, 64);
1031
1032 LE64_BITMASK(BCH_SB_VERSION_UPGRADE_COMPLETE,
1033                                         struct bch_sb, flags[5],  0, 16);
1034
1035 static inline __u64 BCH_SB_COMPRESSION_TYPE(const struct bch_sb *sb)
1036 {
1037         return BCH_SB_COMPRESSION_TYPE_LO(sb) | (BCH_SB_COMPRESSION_TYPE_HI(sb) << 4);
1038 }
1039
1040 static inline void SET_BCH_SB_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1041 {
1042         SET_BCH_SB_COMPRESSION_TYPE_LO(sb, v);
1043         SET_BCH_SB_COMPRESSION_TYPE_HI(sb, v >> 4);
1044 }
1045
1046 static inline __u64 BCH_SB_BACKGROUND_COMPRESSION_TYPE(const struct bch_sb *sb)
1047 {
1048         return BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb) |
1049                 (BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb) << 4);
1050 }
1051
1052 static inline void SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1053 {
1054         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb, v);
1055         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb, v >> 4);
1056 }
1057
1058 /*
1059  * Features:
1060  *
1061  * journal_seq_blacklist_v3:    gates BCH_SB_FIELD_journal_seq_blacklist
1062  * reflink:                     gates KEY_TYPE_reflink
1063  * inline_data:                 gates KEY_TYPE_inline_data
1064  * new_siphash:                 gates BCH_STR_HASH_siphash
1065  * new_extent_overwrite:        gates BTREE_NODE_NEW_EXTENT_OVERWRITE
1066  */
1067 #define BCH_SB_FEATURES()                       \
1068         x(lz4,                          0)      \
1069         x(gzip,                         1)      \
1070         x(zstd,                         2)      \
1071         x(atomic_nlink,                 3)      \
1072         x(ec,                           4)      \
1073         x(journal_seq_blacklist_v3,     5)      \
1074         x(reflink,                      6)      \
1075         x(new_siphash,                  7)      \
1076         x(inline_data,                  8)      \
1077         x(new_extent_overwrite,         9)      \
1078         x(incompressible,               10)     \
1079         x(btree_ptr_v2,                 11)     \
1080         x(extents_above_btree_updates,  12)     \
1081         x(btree_updates_journalled,     13)     \
1082         x(reflink_inline_data,          14)     \
1083         x(new_varint,                   15)     \
1084         x(journal_no_flush,             16)     \
1085         x(alloc_v2,                     17)     \
1086         x(extents_across_btree_nodes,   18)
1087
1088 #define BCH_SB_FEATURES_ALWAYS                          \
1089         ((1ULL << BCH_FEATURE_new_extent_overwrite)|    \
1090          (1ULL << BCH_FEATURE_extents_above_btree_updates)|\
1091          (1ULL << BCH_FEATURE_btree_updates_journalled)|\
1092          (1ULL << BCH_FEATURE_alloc_v2)|\
1093          (1ULL << BCH_FEATURE_extents_across_btree_nodes))
1094
1095 #define BCH_SB_FEATURES_ALL                             \
1096         (BCH_SB_FEATURES_ALWAYS|                        \
1097          (1ULL << BCH_FEATURE_new_siphash)|             \
1098          (1ULL << BCH_FEATURE_btree_ptr_v2)|            \
1099          (1ULL << BCH_FEATURE_new_varint)|              \
1100          (1ULL << BCH_FEATURE_journal_no_flush))
1101
1102 enum bch_sb_feature {
1103 #define x(f, n) BCH_FEATURE_##f,
1104         BCH_SB_FEATURES()
1105 #undef x
1106         BCH_FEATURE_NR,
1107 };
1108
1109 #define BCH_SB_COMPAT()                                 \
1110         x(alloc_info,                           0)      \
1111         x(alloc_metadata,                       1)      \
1112         x(extents_above_btree_updates_done,     2)      \
1113         x(bformat_overflow_done,                3)
1114
1115 enum bch_sb_compat {
1116 #define x(f, n) BCH_COMPAT_##f,
1117         BCH_SB_COMPAT()
1118 #undef x
1119         BCH_COMPAT_NR,
1120 };
1121
1122 /* options: */
1123
1124 #define BCH_VERSION_UPGRADE_OPTS()      \
1125         x(compatible,           0)      \
1126         x(incompatible,         1)      \
1127         x(none,                 2)
1128
1129 enum bch_version_upgrade_opts {
1130 #define x(t, n) BCH_VERSION_UPGRADE_##t = n,
1131         BCH_VERSION_UPGRADE_OPTS()
1132 #undef x
1133 };
1134
1135 #define BCH_REPLICAS_MAX                4U
1136
1137 #define BCH_BKEY_PTRS_MAX               16U
1138
1139 #define BCH_ERROR_ACTIONS()             \
1140         x(continue,             0)      \
1141         x(ro,                   1)      \
1142         x(panic,                2)
1143
1144 enum bch_error_actions {
1145 #define x(t, n) BCH_ON_ERROR_##t = n,
1146         BCH_ERROR_ACTIONS()
1147 #undef x
1148         BCH_ON_ERROR_NR
1149 };
1150
1151 #define BCH_STR_HASH_TYPES()            \
1152         x(crc32c,               0)      \
1153         x(crc64,                1)      \
1154         x(siphash_old,          2)      \
1155         x(siphash,              3)
1156
1157 enum bch_str_hash_type {
1158 #define x(t, n) BCH_STR_HASH_##t = n,
1159         BCH_STR_HASH_TYPES()
1160 #undef x
1161         BCH_STR_HASH_NR
1162 };
1163
1164 #define BCH_STR_HASH_OPTS()             \
1165         x(crc32c,               0)      \
1166         x(crc64,                1)      \
1167         x(siphash,              2)
1168
1169 enum bch_str_hash_opts {
1170 #define x(t, n) BCH_STR_HASH_OPT_##t = n,
1171         BCH_STR_HASH_OPTS()
1172 #undef x
1173         BCH_STR_HASH_OPT_NR
1174 };
1175
1176 #define BCH_CSUM_TYPES()                        \
1177         x(none,                         0)      \
1178         x(crc32c_nonzero,               1)      \
1179         x(crc64_nonzero,                2)      \
1180         x(chacha20_poly1305_80,         3)      \
1181         x(chacha20_poly1305_128,        4)      \
1182         x(crc32c,                       5)      \
1183         x(crc64,                        6)      \
1184         x(xxhash,                       7)
1185
1186 enum bch_csum_type {
1187 #define x(t, n) BCH_CSUM_##t = n,
1188         BCH_CSUM_TYPES()
1189 #undef x
1190         BCH_CSUM_NR
1191 };
1192
1193 static const __maybe_unused unsigned bch_crc_bytes[] = {
1194         [BCH_CSUM_none]                         = 0,
1195         [BCH_CSUM_crc32c_nonzero]               = 4,
1196         [BCH_CSUM_crc32c]                       = 4,
1197         [BCH_CSUM_crc64_nonzero]                = 8,
1198         [BCH_CSUM_crc64]                        = 8,
1199         [BCH_CSUM_xxhash]                       = 8,
1200         [BCH_CSUM_chacha20_poly1305_80]         = 10,
1201         [BCH_CSUM_chacha20_poly1305_128]        = 16,
1202 };
1203
1204 static inline _Bool bch2_csum_type_is_encryption(enum bch_csum_type type)
1205 {
1206         switch (type) {
1207         case BCH_CSUM_chacha20_poly1305_80:
1208         case BCH_CSUM_chacha20_poly1305_128:
1209                 return true;
1210         default:
1211                 return false;
1212         }
1213 }
1214
1215 #define BCH_CSUM_OPTS()                 \
1216         x(none,                 0)      \
1217         x(crc32c,               1)      \
1218         x(crc64,                2)      \
1219         x(xxhash,               3)
1220
1221 enum bch_csum_opts {
1222 #define x(t, n) BCH_CSUM_OPT_##t = n,
1223         BCH_CSUM_OPTS()
1224 #undef x
1225         BCH_CSUM_OPT_NR
1226 };
1227
1228 #define BCH_COMPRESSION_TYPES()         \
1229         x(none,                 0)      \
1230         x(lz4_old,              1)      \
1231         x(gzip,                 2)      \
1232         x(lz4,                  3)      \
1233         x(zstd,                 4)      \
1234         x(incompressible,       5)
1235
1236 enum bch_compression_type {
1237 #define x(t, n) BCH_COMPRESSION_TYPE_##t = n,
1238         BCH_COMPRESSION_TYPES()
1239 #undef x
1240         BCH_COMPRESSION_TYPE_NR
1241 };
1242
1243 #define BCH_COMPRESSION_OPTS()          \
1244         x(none,         0)              \
1245         x(lz4,          1)              \
1246         x(gzip,         2)              \
1247         x(zstd,         3)
1248
1249 enum bch_compression_opts {
1250 #define x(t, n) BCH_COMPRESSION_OPT_##t = n,
1251         BCH_COMPRESSION_OPTS()
1252 #undef x
1253         BCH_COMPRESSION_OPT_NR
1254 };
1255
1256 /*
1257  * Magic numbers
1258  *
1259  * The various other data structures have their own magic numbers, which are
1260  * xored with the first part of the cache set's UUID
1261  */
1262
1263 #define BCACHE_MAGIC                                                    \
1264         UUID_INIT(0xc68573f6, 0x4e1a, 0x45ca,                           \
1265                   0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81)
1266 #define BCHFS_MAGIC                                                     \
1267         UUID_INIT(0xc68573f6, 0x66ce, 0x90a9,                           \
1268                   0xd9, 0x6a, 0x60, 0xcf, 0x80, 0x3d, 0xf7, 0xef)
1269
1270 #define BCACHEFS_STATFS_MAGIC           0xca451a4e
1271
1272 #define JSET_MAGIC              __cpu_to_le64(0x245235c1a3625032ULL)
1273 #define BSET_MAGIC              __cpu_to_le64(0x90135c78b99e07f5ULL)
1274
1275 static inline __le64 __bch2_sb_magic(struct bch_sb *sb)
1276 {
1277         __le64 ret;
1278
1279         memcpy(&ret, &sb->uuid, sizeof(ret));
1280         return ret;
1281 }
1282
1283 static inline __u64 __jset_magic(struct bch_sb *sb)
1284 {
1285         return __le64_to_cpu(__bch2_sb_magic(sb) ^ JSET_MAGIC);
1286 }
1287
1288 static inline __u64 __bset_magic(struct bch_sb *sb)
1289 {
1290         return __le64_to_cpu(__bch2_sb_magic(sb) ^ BSET_MAGIC);
1291 }
1292
1293 /* Journal */
1294
1295 #define JSET_KEYS_U64s  (sizeof(struct jset_entry) / sizeof(__u64))
1296
1297 #define BCH_JSET_ENTRY_TYPES()                  \
1298         x(btree_keys,           0)              \
1299         x(btree_root,           1)              \
1300         x(prio_ptrs,            2)              \
1301         x(blacklist,            3)              \
1302         x(blacklist_v2,         4)              \
1303         x(usage,                5)              \
1304         x(data_usage,           6)              \
1305         x(clock,                7)              \
1306         x(dev_usage,            8)              \
1307         x(log,                  9)              \
1308         x(overwrite,            10)             \
1309         x(write_buffer_keys,    11)             \
1310         x(datetime,             12)
1311
1312 enum {
1313 #define x(f, nr)        BCH_JSET_ENTRY_##f      = nr,
1314         BCH_JSET_ENTRY_TYPES()
1315 #undef x
1316         BCH_JSET_ENTRY_NR
1317 };
1318
1319 static inline bool jset_entry_is_key(struct jset_entry *e)
1320 {
1321         switch (e->type) {
1322         case BCH_JSET_ENTRY_btree_keys:
1323         case BCH_JSET_ENTRY_btree_root:
1324         case BCH_JSET_ENTRY_overwrite:
1325         case BCH_JSET_ENTRY_write_buffer_keys:
1326                 return true;
1327         }
1328
1329         return false;
1330 }
1331
1332 /*
1333  * Journal sequence numbers can be blacklisted: bsets record the max sequence
1334  * number of all the journal entries they contain updates for, so that on
1335  * recovery we can ignore those bsets that contain index updates newer that what
1336  * made it into the journal.
1337  *
1338  * This means that we can't reuse that journal_seq - we have to skip it, and
1339  * then record that we skipped it so that the next time we crash and recover we
1340  * don't think there was a missing journal entry.
1341  */
1342 struct jset_entry_blacklist {
1343         struct jset_entry       entry;
1344         __le64                  seq;
1345 };
1346
1347 struct jset_entry_blacklist_v2 {
1348         struct jset_entry       entry;
1349         __le64                  start;
1350         __le64                  end;
1351 };
1352
1353 #define BCH_FS_USAGE_TYPES()                    \
1354         x(reserved,             0)              \
1355         x(inodes,               1)              \
1356         x(key_version,          2)
1357
1358 enum {
1359 #define x(f, nr)        BCH_FS_USAGE_##f        = nr,
1360         BCH_FS_USAGE_TYPES()
1361 #undef x
1362         BCH_FS_USAGE_NR
1363 };
1364
1365 struct jset_entry_usage {
1366         struct jset_entry       entry;
1367         __le64                  v;
1368 } __packed;
1369
1370 struct jset_entry_data_usage {
1371         struct jset_entry       entry;
1372         __le64                  v;
1373         struct bch_replicas_entry_v1 r;
1374 } __packed;
1375
1376 struct jset_entry_clock {
1377         struct jset_entry       entry;
1378         __u8                    rw;
1379         __u8                    pad[7];
1380         __le64                  time;
1381 } __packed;
1382
1383 struct jset_entry_dev_usage_type {
1384         __le64                  buckets;
1385         __le64                  sectors;
1386         __le64                  fragmented;
1387 } __packed;
1388
1389 struct jset_entry_dev_usage {
1390         struct jset_entry       entry;
1391         __le32                  dev;
1392         __u32                   pad;
1393
1394         __le64                  _buckets_ec;            /* No longer used */
1395         __le64                  _buckets_unavailable;   /* No longer used */
1396
1397         struct jset_entry_dev_usage_type d[];
1398 };
1399
1400 static inline unsigned jset_entry_dev_usage_nr_types(struct jset_entry_dev_usage *u)
1401 {
1402         return (vstruct_bytes(&u->entry) - sizeof(struct jset_entry_dev_usage)) /
1403                 sizeof(struct jset_entry_dev_usage_type);
1404 }
1405
1406 struct jset_entry_log {
1407         struct jset_entry       entry;
1408         u8                      d[];
1409 } __packed __aligned(8);
1410
1411 struct jset_entry_datetime {
1412         struct jset_entry       entry;
1413         __le64                  seconds;
1414 } __packed __aligned(8);
1415
1416 /*
1417  * On disk format for a journal entry:
1418  * seq is monotonically increasing; every journal entry has its own unique
1419  * sequence number.
1420  *
1421  * last_seq is the oldest journal entry that still has keys the btree hasn't
1422  * flushed to disk yet.
1423  *
1424  * version is for on disk format changes.
1425  */
1426 struct jset {
1427         struct bch_csum         csum;
1428
1429         __le64                  magic;
1430         __le64                  seq;
1431         __le32                  version;
1432         __le32                  flags;
1433
1434         __le32                  u64s; /* size of d[] in u64s */
1435
1436         __u8                    encrypted_start[0];
1437
1438         __le16                  _read_clock; /* no longer used */
1439         __le16                  _write_clock;
1440
1441         /* Sequence number of oldest dirty journal entry */
1442         __le64                  last_seq;
1443
1444
1445         struct jset_entry       start[0];
1446         __u64                   _data[];
1447 } __packed __aligned(8);
1448
1449 LE32_BITMASK(JSET_CSUM_TYPE,    struct jset, flags, 0, 4);
1450 LE32_BITMASK(JSET_BIG_ENDIAN,   struct jset, flags, 4, 5);
1451 LE32_BITMASK(JSET_NO_FLUSH,     struct jset, flags, 5, 6);
1452
1453 #define BCH_JOURNAL_BUCKETS_MIN         8
1454
1455 /* Btree: */
1456
1457 enum btree_id_flags {
1458         BTREE_ID_EXTENTS        = BIT(0),
1459         BTREE_ID_SNAPSHOTS      = BIT(1),
1460         BTREE_ID_SNAPSHOT_FIELD = BIT(2),
1461         BTREE_ID_DATA           = BIT(3),
1462 };
1463
1464 #define BCH_BTREE_IDS()                                                         \
1465         x(extents,              0,      BTREE_ID_EXTENTS|BTREE_ID_SNAPSHOTS|BTREE_ID_DATA,\
1466           BIT_ULL(KEY_TYPE_whiteout)|                                           \
1467           BIT_ULL(KEY_TYPE_error)|                                              \
1468           BIT_ULL(KEY_TYPE_cookie)|                                             \
1469           BIT_ULL(KEY_TYPE_extent)|                                             \
1470           BIT_ULL(KEY_TYPE_reservation)|                                        \
1471           BIT_ULL(KEY_TYPE_reflink_p)|                                          \
1472           BIT_ULL(KEY_TYPE_inline_data))                                        \
1473         x(inodes,               1,      BTREE_ID_SNAPSHOTS,                     \
1474           BIT_ULL(KEY_TYPE_whiteout)|                                           \
1475           BIT_ULL(KEY_TYPE_inode)|                                              \
1476           BIT_ULL(KEY_TYPE_inode_v2)|                                           \
1477           BIT_ULL(KEY_TYPE_inode_v3)|                                           \
1478           BIT_ULL(KEY_TYPE_inode_generation))                                   \
1479         x(dirents,              2,      BTREE_ID_SNAPSHOTS,                     \
1480           BIT_ULL(KEY_TYPE_whiteout)|                                           \
1481           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
1482           BIT_ULL(KEY_TYPE_dirent))                                             \
1483         x(xattrs,               3,      BTREE_ID_SNAPSHOTS,                     \
1484           BIT_ULL(KEY_TYPE_whiteout)|                                           \
1485           BIT_ULL(KEY_TYPE_cookie)|                                             \
1486           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
1487           BIT_ULL(KEY_TYPE_xattr))                                              \
1488         x(alloc,                4,      0,                                      \
1489           BIT_ULL(KEY_TYPE_alloc)|                                              \
1490           BIT_ULL(KEY_TYPE_alloc_v2)|                                           \
1491           BIT_ULL(KEY_TYPE_alloc_v3)|                                           \
1492           BIT_ULL(KEY_TYPE_alloc_v4))                                           \
1493         x(quotas,               5,      0,                                      \
1494           BIT_ULL(KEY_TYPE_quota))                                              \
1495         x(stripes,              6,      0,                                      \
1496           BIT_ULL(KEY_TYPE_stripe))                                             \
1497         x(reflink,              7,      BTREE_ID_EXTENTS|BTREE_ID_DATA,         \
1498           BIT_ULL(KEY_TYPE_reflink_v)|                                          \
1499           BIT_ULL(KEY_TYPE_indirect_inline_data))                               \
1500         x(subvolumes,           8,      0,                                      \
1501           BIT_ULL(KEY_TYPE_subvolume))                                          \
1502         x(snapshots,            9,      0,                                      \
1503           BIT_ULL(KEY_TYPE_snapshot))                                           \
1504         x(lru,                  10,     0,                                      \
1505           BIT_ULL(KEY_TYPE_set))                                                \
1506         x(freespace,            11,     BTREE_ID_EXTENTS,                       \
1507           BIT_ULL(KEY_TYPE_set))                                                \
1508         x(need_discard,         12,     0,                                      \
1509           BIT_ULL(KEY_TYPE_set))                                                \
1510         x(backpointers,         13,     0,                                      \
1511           BIT_ULL(KEY_TYPE_backpointer))                                        \
1512         x(bucket_gens,          14,     0,                                      \
1513           BIT_ULL(KEY_TYPE_bucket_gens))                                        \
1514         x(snapshot_trees,       15,     0,                                      \
1515           BIT_ULL(KEY_TYPE_snapshot_tree))                                      \
1516         x(deleted_inodes,       16,     BTREE_ID_SNAPSHOT_FIELD,                \
1517           BIT_ULL(KEY_TYPE_set))                                                \
1518         x(logged_ops,           17,     0,                                      \
1519           BIT_ULL(KEY_TYPE_logged_op_truncate)|                                 \
1520           BIT_ULL(KEY_TYPE_logged_op_finsert))                                  \
1521         x(rebalance_work,       18,     BTREE_ID_SNAPSHOT_FIELD,                \
1522           BIT_ULL(KEY_TYPE_set)|BIT_ULL(KEY_TYPE_cookie))                       \
1523         x(subvolume_children,   19,     0,                                      \
1524           BIT_ULL(KEY_TYPE_set))
1525
1526 enum btree_id {
1527 #define x(name, nr, ...) BTREE_ID_##name = nr,
1528         BCH_BTREE_IDS()
1529 #undef x
1530         BTREE_ID_NR
1531 };
1532
1533 #define BTREE_MAX_DEPTH         4U
1534
1535 /* Btree nodes */
1536
1537 /*
1538  * Btree nodes
1539  *
1540  * On disk a btree node is a list/log of these; within each set the keys are
1541  * sorted
1542  */
1543 struct bset {
1544         __le64                  seq;
1545
1546         /*
1547          * Highest journal entry this bset contains keys for.
1548          * If on recovery we don't see that journal entry, this bset is ignored:
1549          * this allows us to preserve the order of all index updates after a
1550          * crash, since the journal records a total order of all index updates
1551          * and anything that didn't make it to the journal doesn't get used.
1552          */
1553         __le64                  journal_seq;
1554
1555         __le32                  flags;
1556         __le16                  version;
1557         __le16                  u64s; /* count of d[] in u64s */
1558
1559         struct bkey_packed      start[0];
1560         __u64                   _data[];
1561 } __packed __aligned(8);
1562
1563 LE32_BITMASK(BSET_CSUM_TYPE,    struct bset, flags, 0, 4);
1564
1565 LE32_BITMASK(BSET_BIG_ENDIAN,   struct bset, flags, 4, 5);
1566 LE32_BITMASK(BSET_SEPARATE_WHITEOUTS,
1567                                 struct bset, flags, 5, 6);
1568
1569 /* Sector offset within the btree node: */
1570 LE32_BITMASK(BSET_OFFSET,       struct bset, flags, 16, 32);
1571
1572 struct btree_node {
1573         struct bch_csum         csum;
1574         __le64                  magic;
1575
1576         /* this flags field is encrypted, unlike bset->flags: */
1577         __le64                  flags;
1578
1579         /* Closed interval: */
1580         struct bpos             min_key;
1581         struct bpos             max_key;
1582         struct bch_extent_ptr   _ptr; /* not used anymore */
1583         struct bkey_format      format;
1584
1585         union {
1586         struct bset             keys;
1587         struct {
1588                 __u8            pad[22];
1589                 __le16          u64s;
1590                 __u64           _data[0];
1591
1592         };
1593         };
1594 } __packed __aligned(8);
1595
1596 LE64_BITMASK(BTREE_NODE_ID_LO,  struct btree_node, flags,  0,  4);
1597 LE64_BITMASK(BTREE_NODE_LEVEL,  struct btree_node, flags,  4,  8);
1598 LE64_BITMASK(BTREE_NODE_NEW_EXTENT_OVERWRITE,
1599                                 struct btree_node, flags,  8,  9);
1600 LE64_BITMASK(BTREE_NODE_ID_HI,  struct btree_node, flags,  9, 25);
1601 /* 25-32 unused */
1602 LE64_BITMASK(BTREE_NODE_SEQ,    struct btree_node, flags, 32, 64);
1603
1604 static inline __u64 BTREE_NODE_ID(struct btree_node *n)
1605 {
1606         return BTREE_NODE_ID_LO(n) | (BTREE_NODE_ID_HI(n) << 4);
1607 }
1608
1609 static inline void SET_BTREE_NODE_ID(struct btree_node *n, __u64 v)
1610 {
1611         SET_BTREE_NODE_ID_LO(n, v);
1612         SET_BTREE_NODE_ID_HI(n, v >> 4);
1613 }
1614
1615 struct btree_node_entry {
1616         struct bch_csum         csum;
1617
1618         union {
1619         struct bset             keys;
1620         struct {
1621                 __u8            pad[22];
1622                 __le16          u64s;
1623                 __u64           _data[0];
1624         };
1625         };
1626 } __packed __aligned(8);
1627
1628 #endif /* _BCACHEFS_FORMAT_H */