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 /* Extents */
 421
 422 /*
 423  * In extent bkeys, the value is a list of pointers (bch_extent_ptr), optionally
 424  * preceded by checksum/compression information (bch_extent_crc32 or
 425  * bch_extent_crc64).
 426  *
 427  * One major determining factor in the format of extents is how we handle and
 428  * represent extents that have been partially overwritten and thus trimmed:
 429  *
 430  * If an extent is not checksummed or compressed, when the extent is trimmed we
 431  * don't have to remember the extent we originally allocated and wrote: we can
 432  * merely adjust ptr->offset to point to the start of the data that is currently
 433  * live. The size field in struct bkey records the current (live) size of the
 434  * extent, and is also used to mean "size of region on disk that we point to" in
 435  * this case.
 436  *
 437  * Thus an extent that is not checksummed or compressed will consist only of a
 438  * list of bch_extent_ptrs, with none of the fields in
 439  * bch_extent_crc32/bch_extent_crc64.
 440  *
 441  * When an extent is checksummed or compressed, it's not possible to read only
 442  * the data that is currently live: we have to read the entire extent that was
 443  * originally written, and then return only the part of the extent that is
 444  * currently live.
 445  *
 446  * Thus, in addition to the current size of the extent in struct bkey, we need
 447  * to store the size of the originally allocated space - this is the
 448  * compressed_size and uncompressed_size fields in bch_extent_crc32/64. Also,
 449  * when the extent is trimmed, instead of modifying the offset field of the
 450  * pointer, we keep a second smaller offset field - "offset into the original
 451  * extent of the currently live region".
 452  *
 453  * The other major determining factor is replication and data migration:
 454  *
 455  * Each pointer may have its own bch_extent_crc32/64. When doing a replicated
 456  * write, we will initially write all the replicas in the same format, with the
 457  * same checksum type and compression format - however, when copygc runs later (or
 458  * tiering/cache promotion, anything that moves data), it is not in general
 459  * going to rewrite all the pointers at once - one of the replicas may be in a
 460  * bucket on one device that has very little fragmentation while another lives
 461  * in a bucket that has become heavily fragmented, and thus is being rewritten
 462  * sooner than the rest.
 463  *
 464  * Thus it will only move a subset of the pointers (or in the case of
 465  * tiering/cache promotion perhaps add a single pointer without dropping any
 466  * current pointers), and if the extent has been partially overwritten it must
 467  * write only the currently live portion (or copygc would not be able to reduce
 468  * fragmentation!) - which necessitates a different bch_extent_crc format for
 469  * the new pointer.
 470  *
 471  * But in the interests of space efficiency, we don't want to store one
 472  * bch_extent_crc for each pointer if we don't have to.
 473  *
 474  * Thus, a bch_extent consists of bch_extent_crc32s, bch_extent_crc64s, and
 475  * bch_extent_ptrs appended arbitrarily one after the other. We determine the
 476  * type of a given entry with a scheme similar to utf8 (except we're encoding a
 477  * type, not a size), encoding the type in the position of the first set bit:
 478  *
 479  * bch_extent_crc32     - 0b1
 480  * bch_extent_ptr       - 0b10
 481  * bch_extent_crc64     - 0b100
 482  *
 483  * We do it this way because bch_extent_crc32 is _very_ constrained on bits (and
 484  * bch_extent_crc64 is the least constrained).
 485  *
 486  * Then, each bch_extent_crc32/64 applies to the pointers that follow after it,
 487  * until the next bch_extent_crc32/64.
 488  *
 489  * If there are no bch_extent_crcs preceding a bch_extent_ptr, then that pointer
 490  * is neither checksummed nor compressed.
 491  */
 492
 493 /* 128 bits, sufficient for cryptographic MACs: */
 494 struct bch_csum {
 495         __le64                  lo;
 496         __le64                  hi;
 497 } __packed __aligned(8);
 498
 499 #define BCH_EXTENT_ENTRY_TYPES()                \
 500         x(ptr,                  0)              \
 501         x(crc32,                1)              \
 502         x(crc64,                2)              \
 503         x(crc128,               3)              \
 504         x(stripe_ptr,           4)              \
 505         x(rebalance,            5)
 506 #define BCH_EXTENT_ENTRY_MAX    6
 507
 508 enum bch_extent_entry_type {
 509 #define x(f, n) BCH_EXTENT_ENTRY_##f = n,
 510         BCH_EXTENT_ENTRY_TYPES()
 511 #undef x
 512 };
 513
 514 /* Compressed/uncompressed size are stored biased by 1: */
 515 struct bch_extent_crc32 {
 516 #if defined(__LITTLE_ENDIAN_BITFIELD)
 517         __u32                   type:2,
 518                                 _compressed_size:7,
 519                                 _uncompressed_size:7,
 520                                 offset:7,
 521                                 _unused:1,
 522                                 csum_type:4,
 523                                 compression_type:4;
 524         __u32                   csum;
 525 #elif defined (__BIG_ENDIAN_BITFIELD)
 526         __u32                   csum;
 527         __u32                   compression_type:4,
 528                                 csum_type:4,
 529                                 _unused:1,
 530                                 offset:7,
 531                                 _uncompressed_size:7,
 532                                 _compressed_size:7,
 533                                 type:2;
 534 #endif
 535 } __packed __aligned(8);
 536
 537 #define CRC32_SIZE_MAX          (1U << 7)
 538 #define CRC32_NONCE_MAX         0
 539
 540 struct bch_extent_crc64 {
 541 #if defined(__LITTLE_ENDIAN_BITFIELD)
 542         __u64                   type:3,
 543                                 _compressed_size:9,
 544                                 _uncompressed_size:9,
 545                                 offset:9,
 546                                 nonce:10,
 547                                 csum_type:4,
 548                                 compression_type:4,
 549                                 csum_hi:16;
 550 #elif defined (__BIG_ENDIAN_BITFIELD)
 551         __u64                   csum_hi:16,
 552                                 compression_type:4,
 553                                 csum_type:4,
 554                                 nonce:10,
 555                                 offset:9,
 556                                 _uncompressed_size:9,
 557                                 _compressed_size:9,
 558                                 type:3;
 559 #endif
 560         __u64                   csum_lo;
 561 } __packed __aligned(8);
 562
 563 #define CRC64_SIZE_MAX          (1U << 9)
 564 #define CRC64_NONCE_MAX         ((1U << 10) - 1)
 565
 566 struct bch_extent_crc128 {
 567 #if defined(__LITTLE_ENDIAN_BITFIELD)
 568         __u64                   type:4,
 569                                 _compressed_size:13,
 570                                 _uncompressed_size:13,
 571                                 offset:13,
 572                                 nonce:13,
 573                                 csum_type:4,
 574                                 compression_type:4;
 575 #elif defined (__BIG_ENDIAN_BITFIELD)
 576         __u64                   compression_type:4,
 577                                 csum_type:4,
 578                                 nonce:13,
 579                                 offset:13,
 580                                 _uncompressed_size:13,
 581                                 _compressed_size:13,
 582                                 type:4;
 583 #endif
 584         struct bch_csum         csum;
 585 } __packed __aligned(8);
 586
 587 #define CRC128_SIZE_MAX         (1U << 13)
 588 #define CRC128_NONCE_MAX        ((1U << 13) - 1)
 589
 590 /*
 591  * @reservation - pointer hasn't been written to, just reserved
 592  */
 593 struct bch_extent_ptr {
 594 #if defined(__LITTLE_ENDIAN_BITFIELD)
 595         __u64                   type:1,
 596                                 cached:1,
 597                                 unused:1,
 598                                 unwritten:1,
 599                                 offset:44, /* 8 petabytes */
 600                                 dev:8,
 601                                 gen:8;
 602 #elif defined (__BIG_ENDIAN_BITFIELD)
 603         __u64                   gen:8,
 604                                 dev:8,
 605                                 offset:44,
 606                                 unwritten:1,
 607                                 unused:1,
 608                                 cached:1,
 609                                 type:1;
 610 #endif
 611 } __packed __aligned(8);
 612
 613 struct bch_extent_stripe_ptr {
 614 #if defined(__LITTLE_ENDIAN_BITFIELD)
 615         __u64                   type:5,
 616                                 block:8,
 617                                 redundancy:4,
 618                                 idx:47;
 619 #elif defined (__BIG_ENDIAN_BITFIELD)
 620         __u64                   idx:47,
 621                                 redundancy:4,
 622                                 block:8,
 623                                 type:5;
 624 #endif
 625 };
 626
 627 struct bch_extent_rebalance {
 628 #if defined(__LITTLE_ENDIAN_BITFIELD)
 629         __u64                   type:6,
 630                                 unused:34,
 631                                 compression:8, /* enum bch_compression_opt */
 632                                 target:16;
 633 #elif defined (__BIG_ENDIAN_BITFIELD)
 634         __u64                   target:16,
 635                                 compression:8,
 636                                 unused:34,
 637                                 type:6;
 638 #endif
 639 };
 640
 641 union bch_extent_entry {
 642 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ||  __BITS_PER_LONG == 64
 643         unsigned long                   type;
 644 #elif __BITS_PER_LONG == 32
 645         struct {
 646                 unsigned long           pad;
 647                 unsigned long           type;
 648         };
 649 #else
 650 #error edit for your odd byteorder.
 651 #endif
 652
 653 #define x(f, n) struct bch_extent_##f   f;
 654         BCH_EXTENT_ENTRY_TYPES()
 655 #undef x
 656 };
 657
 658 struct bch_btree_ptr {
 659         struct bch_val          v;
 660
 661         __u64                   _data[0];
 662         struct bch_extent_ptr   start[];
 663 } __packed __aligned(8);
 664
 665 struct bch_btree_ptr_v2 {
 666         struct bch_val          v;
 667
 668         __u64                   mem_ptr;
 669         __le64                  seq;
 670         __le16                  sectors_written;
 671         __le16                  flags;
 672         struct bpos             min_key;
 673         __u64                   _data[0];
 674         struct bch_extent_ptr   start[];
 675 } __packed __aligned(8);
 676
 677 LE16_BITMASK(BTREE_PTR_RANGE_UPDATED,   struct bch_btree_ptr_v2, flags, 0, 1);
 678
 679 struct bch_extent {
 680         struct bch_val          v;
 681
 682         __u64                   _data[0];
 683         union bch_extent_entry  start[];
 684 } __packed __aligned(8);
 685
 686 struct bch_reservation {
 687         struct bch_val          v;
 688
 689         __le32                  generation;
 690         __u8                    nr_replicas;
 691         __u8                    pad[3];
 692 } __packed __aligned(8);
 693
 694 /* Maximum size (in u64s) a single pointer could be: */
 695 #define BKEY_EXTENT_PTR_U64s_MAX\
 696         ((sizeof(struct bch_extent_crc128) +                    \
 697           sizeof(struct bch_extent_ptr)) / sizeof(__u64))
 698
 699 /* Maximum possible size of an entire extent value: */
 700 #define BKEY_EXTENT_VAL_U64s_MAX                                \
 701         (1 + BKEY_EXTENT_PTR_U64s_MAX * (BCH_REPLICAS_MAX + 1))
 702
 703 /* * Maximum possible size of an entire extent, key + value: */
 704 #define BKEY_EXTENT_U64s_MAX            (BKEY_U64s + BKEY_EXTENT_VAL_U64s_MAX)
 705
 706 /* Btree pointers don't carry around checksums: */
 707 #define BKEY_BTREE_PTR_VAL_U64s_MAX                             \
 708         ((sizeof(struct bch_btree_ptr_v2) +                     \
 709           sizeof(struct bch_extent_ptr) * BCH_REPLICAS_MAX) / sizeof(__u64))
 710 #define BKEY_BTREE_PTR_U64s_MAX                                 \
 711         (BKEY_U64s + BKEY_BTREE_PTR_VAL_U64s_MAX)
 712
 713 /* Inodes */
 714
 715 #define BLOCKDEV_INODE_MAX      4096
 716
 717 #define BCACHEFS_ROOT_INO       4096
 718
 719 struct bch_inode {
 720         struct bch_val          v;
 721
 722         __le64                  bi_hash_seed;
 723         __le32                  bi_flags;
 724         __le16                  bi_mode;
 725         __u8                    fields[];
 726 } __packed __aligned(8);
 727
 728 struct bch_inode_v2 {
 729         struct bch_val          v;
 730
 731         __le64                  bi_journal_seq;
 732         __le64                  bi_hash_seed;
 733         __le64                  bi_flags;
 734         __le16                  bi_mode;
 735         __u8                    fields[];
 736 } __packed __aligned(8);
 737
 738 struct bch_inode_v3 {
 739         struct bch_val          v;
 740
 741         __le64                  bi_journal_seq;
 742         __le64                  bi_hash_seed;
 743         __le64                  bi_flags;
 744         __le64                  bi_sectors;
 745         __le64                  bi_size;
 746         __le64                  bi_version;
 747         __u8                    fields[];
 748 } __packed __aligned(8);
 749
 750 #define INODEv3_FIELDS_START_INITIAL    6
 751 #define INODEv3_FIELDS_START_CUR        (offsetof(struct bch_inode_v3, fields) / sizeof(__u64))
 752
 753 struct bch_inode_generation {
 754         struct bch_val          v;
 755
 756         __le32                  bi_generation;
 757         __le32                  pad;
 758 } __packed __aligned(8);
 759
 760 /*
 761  * bi_subvol and bi_parent_subvol are only set for subvolume roots:
 762  */
 763
 764 #define BCH_INODE_FIELDS_v2()                   \
 765         x(bi_atime,                     96)     \
 766         x(bi_ctime,                     96)     \
 767         x(bi_mtime,                     96)     \
 768         x(bi_otime,                     96)     \
 769         x(bi_size,                      64)     \
 770         x(bi_sectors,                   64)     \
 771         x(bi_uid,                       32)     \
 772         x(bi_gid,                       32)     \
 773         x(bi_nlink,                     32)     \
 774         x(bi_generation,                32)     \
 775         x(bi_dev,                       32)     \
 776         x(bi_data_checksum,             8)      \
 777         x(bi_compression,               8)      \
 778         x(bi_project,                   32)     \
 779         x(bi_background_compression,    8)      \
 780         x(bi_data_replicas,             8)      \
 781         x(bi_promote_target,            16)     \
 782         x(bi_foreground_target,         16)     \
 783         x(bi_background_target,         16)     \
 784         x(bi_erasure_code,              16)     \
 785         x(bi_fields_set,                16)     \
 786         x(bi_dir,                       64)     \
 787         x(bi_dir_offset,                64)     \
 788         x(bi_subvol,                    32)     \
 789         x(bi_parent_subvol,             32)
 790
 791 #define BCH_INODE_FIELDS_v3()                   \
 792         x(bi_atime,                     96)     \
 793         x(bi_ctime,                     96)     \
 794         x(bi_mtime,                     96)     \
 795         x(bi_otime,                     96)     \
 796         x(bi_uid,                       32)     \
 797         x(bi_gid,                       32)     \
 798         x(bi_nlink,                     32)     \
 799         x(bi_generation,                32)     \
 800         x(bi_dev,                       32)     \
 801         x(bi_data_checksum,             8)      \
 802         x(bi_compression,               8)      \
 803         x(bi_project,                   32)     \
 804         x(bi_background_compression,    8)      \
 805         x(bi_data_replicas,             8)      \
 806         x(bi_promote_target,            16)     \
 807         x(bi_foreground_target,         16)     \
 808         x(bi_background_target,         16)     \
 809         x(bi_erasure_code,              16)     \
 810         x(bi_fields_set,                16)     \
 811         x(bi_dir,                       64)     \
 812         x(bi_dir_offset,                64)     \
 813         x(bi_subvol,                    32)     \
 814         x(bi_parent_subvol,             32)     \
 815         x(bi_nocow,                     8)
 816
 817 /* subset of BCH_INODE_FIELDS */
 818 #define BCH_INODE_OPTS()                        \
 819         x(data_checksum,                8)      \
 820         x(compression,                  8)      \
 821         x(project,                      32)     \
 822         x(background_compression,       8)      \
 823         x(data_replicas,                8)      \
 824         x(promote_target,               16)     \
 825         x(foreground_target,            16)     \
 826         x(background_target,            16)     \
 827         x(erasure_code,                 16)     \
 828         x(nocow,                        8)
 829
 830 enum inode_opt_id {
 831 #define x(name, ...)                            \
 832         Inode_opt_##name,
 833         BCH_INODE_OPTS()
 834 #undef  x
 835         Inode_opt_nr,
 836 };
 837
 838 #define BCH_INODE_FLAGS()                       \
 839         x(sync,                         0)      \
 840         x(immutable,                    1)      \
 841         x(append,                       2)      \
 842         x(nodump,                       3)      \
 843         x(noatime,                      4)      \
 844         x(i_size_dirty,                 5)      \
 845         x(i_sectors_dirty,              6)      \
 846         x(unlinked,                     7)      \
 847         x(backptr_untrusted,            8)
 848
 849 /* bits 20+ reserved for packed fields below: */
 850
 851 enum bch_inode_flags {
 852 #define x(t, n) BCH_INODE_##t = 1U << n,
 853         BCH_INODE_FLAGS()
 854 #undef x
 855 };
 856
 857 enum __bch_inode_flags {
 858 #define x(t, n) __BCH_INODE_##t = n,
 859         BCH_INODE_FLAGS()
 860 #undef x
 861 };
 862
 863 LE32_BITMASK(INODE_STR_HASH,    struct bch_inode, bi_flags, 20, 24);
 864 LE32_BITMASK(INODE_NR_FIELDS,   struct bch_inode, bi_flags, 24, 31);
 865 LE32_BITMASK(INODE_NEW_VARINT,  struct bch_inode, bi_flags, 31, 32);
 866
 867 LE64_BITMASK(INODEv2_STR_HASH,  struct bch_inode_v2, bi_flags, 20, 24);
 868 LE64_BITMASK(INODEv2_NR_FIELDS, struct bch_inode_v2, bi_flags, 24, 31);
 869
 870 LE64_BITMASK(INODEv3_STR_HASH,  struct bch_inode_v3, bi_flags, 20, 24);
 871 LE64_BITMASK(INODEv3_NR_FIELDS, struct bch_inode_v3, bi_flags, 24, 31);
 872
 873 LE64_BITMASK(INODEv3_FIELDS_START,
 874                                 struct bch_inode_v3, bi_flags, 31, 36);
 875 LE64_BITMASK(INODEv3_MODE,      struct bch_inode_v3, bi_flags, 36, 52);
 876
 877 /* Dirents */
 878
 879 /*
 880  * Dirents (and xattrs) have to implement string lookups; since our b-tree
 881  * doesn't support arbitrary length strings for the key, we instead index by a
 882  * 64 bit hash (currently truncated sha1) of the string, stored in the offset
 883  * field of the key - using linear probing to resolve hash collisions. This also
 884  * provides us with the readdir cookie posix requires.
 885  *
 886  * Linear probing requires us to use whiteouts for deletions, in the event of a
 887  * collision:
 888  */
 889
 890 struct bch_dirent {
 891         struct bch_val          v;
 892
 893         /* Target inode number: */
 894         union {
 895         __le64                  d_inum;
 896         struct {                /* DT_SUBVOL */
 897         __le32                  d_child_subvol;
 898         __le32                  d_parent_subvol;
 899         };
 900         };
 901
 902         /*
 903          * Copy of mode bits 12-15 from the target inode - so userspace can get
 904          * the filetype without having to do a stat()
 905          */
 906         __u8                    d_type;
 907
 908         __u8                    d_name[];
 909 } __packed __aligned(8);
 910
 911 #define DT_SUBVOL       16
 912 #define BCH_DT_MAX      17
 913
 914 #define BCH_NAME_MAX    512
 915
 916 /* Xattrs */
 917
 918 #define KEY_TYPE_XATTR_INDEX_USER                       0
 919 #define KEY_TYPE_XATTR_INDEX_POSIX_ACL_ACCESS   1
 920 #define KEY_TYPE_XATTR_INDEX_POSIX_ACL_DEFAULT  2
 921 #define KEY_TYPE_XATTR_INDEX_TRUSTED                    3
 922 #define KEY_TYPE_XATTR_INDEX_SECURITY           4
 923
 924 struct bch_xattr {
 925         struct bch_val          v;
 926         __u8                    x_type;
 927         __u8                    x_name_len;
 928         __le16                  x_val_len;
 929         __u8                    x_name[];
 930 } __packed __aligned(8);
 931
 932 /* Bucket/allocation information: */
 933
 934 struct bch_alloc {
 935         struct bch_val          v;
 936         __u8                    fields;
 937         __u8                    gen;
 938         __u8                    data[];
 939 } __packed __aligned(8);
 940
 941 #define BCH_ALLOC_FIELDS_V1()                   \
 942         x(read_time,            16)             \
 943         x(write_time,           16)             \
 944         x(data_type,            8)              \
 945         x(dirty_sectors,        16)             \
 946         x(cached_sectors,       16)             \
 947         x(oldest_gen,           8)              \
 948         x(stripe,               32)             \
 949         x(stripe_redundancy,    8)
 950
 951 enum {
 952 #define x(name, _bits) BCH_ALLOC_FIELD_V1_##name,
 953         BCH_ALLOC_FIELDS_V1()
 954 #undef x
 955 };
 956
 957 struct bch_alloc_v2 {
 958         struct bch_val          v;
 959         __u8                    nr_fields;
 960         __u8                    gen;
 961         __u8                    oldest_gen;
 962         __u8                    data_type;
 963         __u8                    data[];
 964 } __packed __aligned(8);
 965
 966 #define BCH_ALLOC_FIELDS_V2()                   \
 967         x(read_time,            64)             \
 968         x(write_time,           64)             \
 969         x(dirty_sectors,        32)             \
 970         x(cached_sectors,       32)             \
 971         x(stripe,               32)             \
 972         x(stripe_redundancy,    8)
 973
 974 struct bch_alloc_v3 {
 975         struct bch_val          v;
 976         __le64                  journal_seq;
 977         __le32                  flags;
 978         __u8                    nr_fields;
 979         __u8                    gen;
 980         __u8                    oldest_gen;
 981         __u8                    data_type;
 982         __u8                    data[];
 983 } __packed __aligned(8);
 984
 985 LE32_BITMASK(BCH_ALLOC_V3_NEED_DISCARD,struct bch_alloc_v3, flags,  0,  1)
 986 LE32_BITMASK(BCH_ALLOC_V3_NEED_INC_GEN,struct bch_alloc_v3, flags,  1,  2)
 987
 988 struct bch_alloc_v4 {
 989         struct bch_val          v;
 990         __u64                   journal_seq;
 991         __u32                   flags;
 992         __u8                    gen;
 993         __u8                    oldest_gen;
 994         __u8                    data_type;
 995         __u8                    stripe_redundancy;
 996         __u32                   dirty_sectors;
 997         __u32                   cached_sectors;
 998         __u64                   io_time[2];
 999         __u32                   stripe;
1000         __u32                   nr_external_backpointers;
1001         __u64                   fragmentation_lru;
1002 } __packed __aligned(8);
1003
1004 #define BCH_ALLOC_V4_U64s_V0    6
1005 #define BCH_ALLOC_V4_U64s       (sizeof(struct bch_alloc_v4) / sizeof(__u64))
1006
1007 BITMASK(BCH_ALLOC_V4_NEED_DISCARD,      struct bch_alloc_v4, flags,  0,  1)
1008 BITMASK(BCH_ALLOC_V4_NEED_INC_GEN,      struct bch_alloc_v4, flags,  1,  2)
1009 BITMASK(BCH_ALLOC_V4_BACKPOINTERS_START,struct bch_alloc_v4, flags,  2,  8)
1010 BITMASK(BCH_ALLOC_V4_NR_BACKPOINTERS,   struct bch_alloc_v4, flags,  8,  14)
1011
1012 #define BCH_ALLOC_V4_NR_BACKPOINTERS_MAX        40
1013
1014 struct bch_backpointer {
1015         struct bch_val          v;
1016         __u8                    btree_id;
1017         __u8                    level;
1018         __u8                    data_type;
1019         __u64                   bucket_offset:40;
1020         __u32                   bucket_len;
1021         struct bpos             pos;
1022 } __packed __aligned(8);
1023
1024 #define KEY_TYPE_BUCKET_GENS_BITS       8
1025 #define KEY_TYPE_BUCKET_GENS_NR         (1U << KEY_TYPE_BUCKET_GENS_BITS)
1026 #define KEY_TYPE_BUCKET_GENS_MASK       (KEY_TYPE_BUCKET_GENS_NR - 1)
1027
1028 struct bch_bucket_gens {
1029         struct bch_val          v;
1030         u8                      gens[KEY_TYPE_BUCKET_GENS_NR];
1031 } __packed __aligned(8);
1032
1033 /* Quotas: */
1034
1035 enum quota_types {
1036         QTYP_USR                = 0,
1037         QTYP_GRP                = 1,
1038         QTYP_PRJ                = 2,
1039         QTYP_NR                 = 3,
1040 };
1041
1042 enum quota_counters {
1043         Q_SPC                   = 0,
1044         Q_INO                   = 1,
1045         Q_COUNTERS              = 2,
1046 };
1047
1048 struct bch_quota_counter {
1049         __le64                  hardlimit;
1050         __le64                  softlimit;
1051 };
1052
1053 struct bch_quota {
1054         struct bch_val          v;
1055         struct bch_quota_counter c[Q_COUNTERS];
1056 } __packed __aligned(8);
1057
1058 /* Erasure coding */
1059
1060 struct bch_stripe {
1061         struct bch_val          v;
1062         __le16                  sectors;
1063         __u8                    algorithm;
1064         __u8                    nr_blocks;
1065         __u8                    nr_redundant;
1066
1067         __u8                    csum_granularity_bits;
1068         __u8                    csum_type;
1069         __u8                    pad;
1070
1071         struct bch_extent_ptr   ptrs[];
1072 } __packed __aligned(8);
1073
1074 /* Reflink: */
1075
1076 struct bch_reflink_p {
1077         struct bch_val          v;
1078         __le64                  idx;
1079         /*
1080          * A reflink pointer might point to an indirect extent which is then
1081          * later split (by copygc or rebalance). If we only pointed to part of
1082          * the original indirect extent, and then one of the fragments is
1083          * outside the range we point to, we'd leak a refcount: so when creating
1084          * reflink pointers, we need to store pad values to remember the full
1085          * range we were taking a reference on.
1086          */
1087         __le32                  front_pad;
1088         __le32                  back_pad;
1089 } __packed __aligned(8);
1090
1091 struct bch_reflink_v {
1092         struct bch_val          v;
1093         __le64                  refcount;
1094         union bch_extent_entry  start[0];
1095         __u64                   _data[];
1096 } __packed __aligned(8);
1097
1098 struct bch_indirect_inline_data {
1099         struct bch_val          v;
1100         __le64                  refcount;
1101         u8                      data[];
1102 };
1103
1104 /* Inline data */
1105
1106 struct bch_inline_data {
1107         struct bch_val          v;
1108         u8                      data[];
1109 };
1110
1111 /* Subvolumes: */
1112
1113 #define SUBVOL_POS_MIN          POS(0, 1)
1114 #define SUBVOL_POS_MAX          POS(0, S32_MAX)
1115 #define BCACHEFS_ROOT_SUBVOL    1
1116
1117 struct bch_subvolume {
1118         struct bch_val          v;
1119         __le32                  flags;
1120         __le32                  snapshot;
1121         __le64                  inode;
1122         /*
1123          * Snapshot subvolumes form a tree, separate from the snapshot nodes
1124          * tree - if this subvolume is a snapshot, this is the ID of the
1125          * subvolume it was created from:
1126          */
1127         __le32                  parent;
1128         __le32                  pad;
1129         bch_le128               otime;
1130 };
1131
1132 LE32_BITMASK(BCH_SUBVOLUME_RO,          struct bch_subvolume, flags,  0,  1)
1133 /*
1134  * We need to know whether a subvolume is a snapshot so we can know whether we
1135  * can delete it (or whether it should just be rm -rf'd)
1136  */
1137 LE32_BITMASK(BCH_SUBVOLUME_SNAP,        struct bch_subvolume, flags,  1,  2)
1138 LE32_BITMASK(BCH_SUBVOLUME_UNLINKED,    struct bch_subvolume, flags,  2,  3)
1139
1140 /* Snapshots */
1141
1142 struct bch_snapshot {
1143         struct bch_val          v;
1144         __le32                  flags;
1145         __le32                  parent;
1146         __le32                  children[2];
1147         __le32                  subvol;
1148         /* corresponds to a bch_snapshot_tree in BTREE_ID_snapshot_trees */
1149         __le32                  tree;
1150         __le32                  depth;
1151         __le32                  skip[3];
1152 };
1153
1154 LE32_BITMASK(BCH_SNAPSHOT_DELETED,      struct bch_snapshot, flags,  0,  1)
1155
1156 /* True if a subvolume points to this snapshot node: */
1157 LE32_BITMASK(BCH_SNAPSHOT_SUBVOL,       struct bch_snapshot, flags,  1,  2)
1158
1159 /*
1160  * Snapshot trees:
1161  *
1162  * The snapshot_trees btree gives us persistent indentifier for each tree of
1163  * bch_snapshot nodes, and allow us to record and easily find the root/master
1164  * subvolume that other snapshots were created from:
1165  */
1166 struct bch_snapshot_tree {
1167         struct bch_val          v;
1168         __le32                  master_subvol;
1169         __le32                  root_snapshot;
1170 };
1171
1172 /* LRU btree: */
1173
1174 struct bch_lru {
1175         struct bch_val          v;
1176         __le64                  idx;
1177 } __packed __aligned(8);
1178
1179 #define LRU_ID_STRIPES          (1U << 16)
1180
1181 /* Logged operations btree: */
1182
1183 struct bch_logged_op_truncate {
1184         struct bch_val          v;
1185         __le32                  subvol;
1186         __le32                  pad;
1187         __le64                  inum;
1188         __le64                  new_i_size;
1189 };
1190
1191 enum logged_op_finsert_state {
1192         LOGGED_OP_FINSERT_start,
1193         LOGGED_OP_FINSERT_shift_extents,
1194         LOGGED_OP_FINSERT_finish,
1195 };
1196
1197 struct bch_logged_op_finsert {
1198         struct bch_val          v;
1199         __u8                    state;
1200         __u8                    pad[3];
1201         __le32                  subvol;
1202         __le64                  inum;
1203         __le64                  dst_offset;
1204         __le64                  src_offset;
1205         __le64                  pos;
1206 };
1207
1208 /* Optional/variable size superblock sections: */
1209
1210 struct bch_sb_field {
1211         __u64                   _data[0];
1212         __le32                  u64s;
1213         __le32                  type;
1214 };
1215
1216 #define BCH_SB_FIELDS()                         \
1217         x(journal,      0)                      \
1218         x(members_v1,   1)                      \
1219         x(crypt,        2)                      \
1220         x(replicas_v0,  3)                      \
1221         x(quota,        4)                      \
1222         x(disk_groups,  5)                      \
1223         x(clean,        6)                      \
1224         x(replicas,     7)                      \
1225         x(journal_seq_blacklist, 8)             \
1226         x(journal_v2,   9)                      \
1227         x(counters,     10)                     \
1228         x(members_v2,   11)                     \
1229         x(errors,       12)
1230
1231 enum bch_sb_field_type {
1232 #define x(f, nr)        BCH_SB_FIELD_##f = nr,
1233         BCH_SB_FIELDS()
1234 #undef x
1235         BCH_SB_FIELD_NR
1236 };
1237
1238 /*
1239  * Most superblock fields are replicated in all device's superblocks - a few are
1240  * not:
1241  */
1242 #define BCH_SINGLE_DEVICE_SB_FIELDS             \
1243         ((1U << BCH_SB_FIELD_journal)|          \
1244          (1U << BCH_SB_FIELD_journal_v2))
1245
1246 /* BCH_SB_FIELD_journal: */
1247
1248 struct bch_sb_field_journal {
1249         struct bch_sb_field     field;
1250         __le64                  buckets[];
1251 };
1252
1253 struct bch_sb_field_journal_v2 {
1254         struct bch_sb_field     field;
1255
1256         struct bch_sb_field_journal_v2_entry {
1257                 __le64          start;
1258                 __le64          nr;
1259         }                       d[];
1260 };
1261
1262 /* BCH_SB_FIELD_members_v1: */
1263
1264 #define BCH_MIN_NR_NBUCKETS     (1 << 6)
1265
1266 #define BCH_IOPS_MEASUREMENTS()                 \
1267         x(seqread,      0)                      \
1268         x(seqwrite,     1)                      \
1269         x(randread,     2)                      \
1270         x(randwrite,    3)
1271
1272 enum bch_iops_measurement {
1273 #define x(t, n) BCH_IOPS_##t = n,
1274         BCH_IOPS_MEASUREMENTS()
1275 #undef x
1276         BCH_IOPS_NR
1277 };
1278
1279 #define BCH_MEMBER_ERROR_TYPES()                \
1280         x(read,         0)                      \
1281         x(write,        1)                      \
1282         x(checksum,     2)
1283
1284 enum bch_member_error_type {
1285 #define x(t, n) BCH_MEMBER_ERROR_##t = n,
1286         BCH_MEMBER_ERROR_TYPES()
1287 #undef x
1288         BCH_MEMBER_ERROR_NR
1289 };
1290
1291 struct bch_member {
1292         __uuid_t                uuid;
1293         __le64                  nbuckets;       /* device size */
1294         __le16                  first_bucket;   /* index of first bucket used */
1295         __le16                  bucket_size;    /* sectors */
1296         __le32                  pad;
1297         __le64                  last_mount;     /* time_t */
1298
1299         __le64                  flags;
1300         __le32                  iops[4];
1301         __le64                  errors[BCH_MEMBER_ERROR_NR];
1302         __le64                  errors_at_reset[BCH_MEMBER_ERROR_NR];
1303         __le64                  errors_reset_time;
1304         __le64                  seq;
1305 };
1306
1307 #define BCH_MEMBER_V1_BYTES     56
1308
1309 LE64_BITMASK(BCH_MEMBER_STATE,          struct bch_member, flags,  0,  4)
1310 /* 4-14 unused, was TIER, HAS_(META)DATA, REPLACEMENT */
1311 LE64_BITMASK(BCH_MEMBER_DISCARD,        struct bch_member, flags, 14, 15)
1312 LE64_BITMASK(BCH_MEMBER_DATA_ALLOWED,   struct bch_member, flags, 15, 20)
1313 LE64_BITMASK(BCH_MEMBER_GROUP,          struct bch_member, flags, 20, 28)
1314 LE64_BITMASK(BCH_MEMBER_DURABILITY,     struct bch_member, flags, 28, 30)
1315 LE64_BITMASK(BCH_MEMBER_FREESPACE_INITIALIZED,
1316                                         struct bch_member, flags, 30, 31)
1317
1318 #if 0
1319 LE64_BITMASK(BCH_MEMBER_NR_READ_ERRORS, struct bch_member, flags[1], 0,  20);
1320 LE64_BITMASK(BCH_MEMBER_NR_WRITE_ERRORS,struct bch_member, flags[1], 20, 40);
1321 #endif
1322
1323 #define BCH_MEMBER_STATES()                     \
1324         x(rw,           0)                      \
1325         x(ro,           1)                      \
1326         x(failed,       2)                      \
1327         x(spare,        3)
1328
1329 enum bch_member_state {
1330 #define x(t, n) BCH_MEMBER_STATE_##t = n,
1331         BCH_MEMBER_STATES()
1332 #undef x
1333         BCH_MEMBER_STATE_NR
1334 };
1335
1336 struct bch_sb_field_members_v1 {
1337         struct bch_sb_field     field;
1338         struct bch_member       _members[]; //Members are now variable size
1339 };
1340
1341 struct bch_sb_field_members_v2 {
1342         struct bch_sb_field     field;
1343         __le16                  member_bytes; //size of single member entry
1344         u8                      pad[6];
1345         struct bch_member       _members[];
1346 };
1347
1348 /* BCH_SB_FIELD_crypt: */
1349
1350 struct nonce {
1351         __le32                  d[4];
1352 };
1353
1354 struct bch_key {
1355         __le64                  key[4];
1356 };
1357
1358 #define BCH_KEY_MAGIC                                   \
1359         (((__u64) 'b' <<  0)|((__u64) 'c' <<  8)|               \
1360          ((__u64) 'h' << 16)|((__u64) '*' << 24)|               \
1361          ((__u64) '*' << 32)|((__u64) 'k' << 40)|               \
1362          ((__u64) 'e' << 48)|((__u64) 'y' << 56))
1363
1364 struct bch_encrypted_key {
1365         __le64                  magic;
1366         struct bch_key          key;
1367 };
1368
1369 /*
1370  * If this field is present in the superblock, it stores an encryption key which
1371  * is used encrypt all other data/metadata. The key will normally be encrypted
1372  * with the key userspace provides, but if encryption has been turned off we'll
1373  * just store the master key unencrypted in the superblock so we can access the
1374  * previously encrypted data.
1375  */
1376 struct bch_sb_field_crypt {
1377         struct bch_sb_field     field;
1378
1379         __le64                  flags;
1380         __le64                  kdf_flags;
1381         struct bch_encrypted_key key;
1382 };
1383
1384 LE64_BITMASK(BCH_CRYPT_KDF_TYPE,        struct bch_sb_field_crypt, flags, 0, 4);
1385
1386 enum bch_kdf_types {
1387         BCH_KDF_SCRYPT          = 0,
1388         BCH_KDF_NR              = 1,
1389 };
1390
1391 /* stored as base 2 log of scrypt params: */
1392 LE64_BITMASK(BCH_KDF_SCRYPT_N,  struct bch_sb_field_crypt, kdf_flags,  0, 16);
1393 LE64_BITMASK(BCH_KDF_SCRYPT_R,  struct bch_sb_field_crypt, kdf_flags, 16, 32);
1394 LE64_BITMASK(BCH_KDF_SCRYPT_P,  struct bch_sb_field_crypt, kdf_flags, 32, 48);
1395
1396 /* BCH_SB_FIELD_replicas: */
1397
1398 #define BCH_DATA_TYPES()                \
1399         x(free,         0)              \
1400         x(sb,           1)              \
1401         x(journal,      2)              \
1402         x(btree,        3)              \
1403         x(user,         4)              \
1404         x(cached,       5)              \
1405         x(parity,       6)              \
1406         x(stripe,       7)              \
1407         x(need_gc_gens, 8)              \
1408         x(need_discard, 9)
1409
1410 enum bch_data_type {
1411 #define x(t, n) BCH_DATA_##t,
1412         BCH_DATA_TYPES()
1413 #undef x
1414         BCH_DATA_NR
1415 };
1416
1417 static inline bool data_type_is_empty(enum bch_data_type type)
1418 {
1419         switch (type) {
1420         case BCH_DATA_free:
1421         case BCH_DATA_need_gc_gens:
1422         case BCH_DATA_need_discard:
1423                 return true;
1424         default:
1425                 return false;
1426         }
1427 }
1428
1429 static inline bool data_type_is_hidden(enum bch_data_type type)
1430 {
1431         switch (type) {
1432         case BCH_DATA_sb:
1433         case BCH_DATA_journal:
1434                 return true;
1435         default:
1436                 return false;
1437         }
1438 }
1439
1440 struct bch_replicas_entry_v0 {
1441         __u8                    data_type;
1442         __u8                    nr_devs;
1443         __u8                    devs[];
1444 } __packed;
1445
1446 struct bch_sb_field_replicas_v0 {
1447         struct bch_sb_field     field;
1448         struct bch_replicas_entry_v0 entries[];
1449 } __packed __aligned(8);
1450
1451 struct bch_replicas_entry_v1 {
1452         __u8                    data_type;
1453         __u8                    nr_devs;
1454         __u8                    nr_required;
1455         __u8                    devs[];
1456 } __packed;
1457
1458 #define replicas_entry_bytes(_i)                                        \
1459         (offsetof(typeof(*(_i)), devs) + (_i)->nr_devs)
1460
1461 struct bch_sb_field_replicas {
1462         struct bch_sb_field     field;
1463         struct bch_replicas_entry_v1 entries[];
1464 } __packed __aligned(8);
1465
1466 /* BCH_SB_FIELD_quota: */
1467
1468 struct bch_sb_quota_counter {
1469         __le32                          timelimit;
1470         __le32                          warnlimit;
1471 };
1472
1473 struct bch_sb_quota_type {
1474         __le64                          flags;
1475         struct bch_sb_quota_counter     c[Q_COUNTERS];
1476 };
1477
1478 struct bch_sb_field_quota {
1479         struct bch_sb_field             field;
1480         struct bch_sb_quota_type        q[QTYP_NR];
1481 } __packed __aligned(8);
1482
1483 /* BCH_SB_FIELD_disk_groups: */
1484
1485 #define BCH_SB_LABEL_SIZE               32
1486
1487 struct bch_disk_group {
1488         __u8                    label[BCH_SB_LABEL_SIZE];
1489         __le64                  flags[2];
1490 } __packed __aligned(8);
1491
1492 LE64_BITMASK(BCH_GROUP_DELETED,         struct bch_disk_group, flags[0], 0,  1)
1493 LE64_BITMASK(BCH_GROUP_DATA_ALLOWED,    struct bch_disk_group, flags[0], 1,  6)
1494 LE64_BITMASK(BCH_GROUP_PARENT,          struct bch_disk_group, flags[0], 6, 24)
1495
1496 struct bch_sb_field_disk_groups {
1497         struct bch_sb_field     field;
1498         struct bch_disk_group   entries[];
1499 } __packed __aligned(8);
1500
1501 /* BCH_SB_FIELD_counters */
1502
1503 #define BCH_PERSISTENT_COUNTERS()                               \
1504         x(io_read,                                      0)      \
1505         x(io_write,                                     1)      \
1506         x(io_move,                                      2)      \
1507         x(bucket_invalidate,                            3)      \
1508         x(bucket_discard,                               4)      \
1509         x(bucket_alloc,                                 5)      \
1510         x(bucket_alloc_fail,                            6)      \
1511         x(btree_cache_scan,                             7)      \
1512         x(btree_cache_reap,                             8)      \
1513         x(btree_cache_cannibalize,                      9)      \
1514         x(btree_cache_cannibalize_lock,                 10)     \
1515         x(btree_cache_cannibalize_lock_fail,            11)     \
1516         x(btree_cache_cannibalize_unlock,               12)     \
1517         x(btree_node_write,                             13)     \
1518         x(btree_node_read,                              14)     \
1519         x(btree_node_compact,                           15)     \
1520         x(btree_node_merge,                             16)     \
1521         x(btree_node_split,                             17)     \
1522         x(btree_node_rewrite,                           18)     \
1523         x(btree_node_alloc,                             19)     \
1524         x(btree_node_free,                              20)     \
1525         x(btree_node_set_root,                          21)     \
1526         x(btree_path_relock_fail,                       22)     \
1527         x(btree_path_upgrade_fail,                      23)     \
1528         x(btree_reserve_get_fail,                       24)     \
1529         x(journal_entry_full,                           25)     \
1530         x(journal_full,                                 26)     \
1531         x(journal_reclaim_finish,                       27)     \
1532         x(journal_reclaim_start,                        28)     \
1533         x(journal_write,                                29)     \
1534         x(read_promote,                                 30)     \
1535         x(read_bounce,                                  31)     \
1536         x(read_split,                                   33)     \
1537         x(read_retry,                                   32)     \
1538         x(read_reuse_race,                              34)     \
1539         x(move_extent_read,                             35)     \
1540         x(move_extent_write,                            36)     \
1541         x(move_extent_finish,                           37)     \
1542         x(move_extent_fail,                             38)     \
1543         x(move_extent_start_fail,                       39)     \
1544         x(copygc,                                       40)     \
1545         x(copygc_wait,                                  41)     \
1546         x(gc_gens_end,                                  42)     \
1547         x(gc_gens_start,                                43)     \
1548         x(trans_blocked_journal_reclaim,                44)     \
1549         x(trans_restart_btree_node_reused,              45)     \
1550         x(trans_restart_btree_node_split,               46)     \
1551         x(trans_restart_fault_inject,                   47)     \
1552         x(trans_restart_iter_upgrade,                   48)     \
1553         x(trans_restart_journal_preres_get,             49)     \
1554         x(trans_restart_journal_reclaim,                50)     \
1555         x(trans_restart_journal_res_get,                51)     \
1556         x(trans_restart_key_cache_key_realloced,        52)     \
1557         x(trans_restart_key_cache_raced,                53)     \
1558         x(trans_restart_mark_replicas,                  54)     \
1559         x(trans_restart_mem_realloced,                  55)     \
1560         x(trans_restart_memory_allocation_failure,      56)     \
1561         x(trans_restart_relock,                         57)     \
1562         x(trans_restart_relock_after_fill,              58)     \
1563         x(trans_restart_relock_key_cache_fill,          59)     \
1564         x(trans_restart_relock_next_node,               60)     \
1565         x(trans_restart_relock_parent_for_fill,         61)     \
1566         x(trans_restart_relock_path,                    62)     \
1567         x(trans_restart_relock_path_intent,             63)     \
1568         x(trans_restart_too_many_iters,                 64)     \
1569         x(trans_restart_traverse,                       65)     \
1570         x(trans_restart_upgrade,                        66)     \
1571         x(trans_restart_would_deadlock,                 67)     \
1572         x(trans_restart_would_deadlock_write,           68)     \
1573         x(trans_restart_injected,                       69)     \
1574         x(trans_restart_key_cache_upgrade,              70)     \
1575         x(trans_traverse_all,                           71)     \
1576         x(transaction_commit,                           72)     \
1577         x(write_super,                                  73)     \
1578         x(trans_restart_would_deadlock_recursion_limit, 74)     \
1579         x(trans_restart_write_buffer_flush,             75)     \
1580         x(trans_restart_split_race,                     76)     \
1581         x(write_buffer_flush_slowpath,                  77)     \
1582         x(write_buffer_flush_sync,                      78)
1583
1584 enum bch_persistent_counters {
1585 #define x(t, n, ...) BCH_COUNTER_##t,
1586         BCH_PERSISTENT_COUNTERS()
1587 #undef x
1588         BCH_COUNTER_NR
1589 };
1590
1591 struct bch_sb_field_counters {
1592         struct bch_sb_field     field;
1593         __le64                  d[];
1594 };
1595
1596 /*
1597  * On clean shutdown, store btree roots and current journal sequence number in
1598  * the superblock:
1599  */
1600 struct jset_entry {
1601         __le16                  u64s;
1602         __u8                    btree_id;
1603         __u8                    level;
1604         __u8                    type; /* designates what this jset holds */
1605         __u8                    pad[3];
1606
1607         struct bkey_i           start[0];
1608         __u64                   _data[];
1609 };
1610
1611 struct bch_sb_field_clean {
1612         struct bch_sb_field     field;
1613
1614         __le32                  flags;
1615         __le16                  _read_clock; /* no longer used */
1616         __le16                  _write_clock;
1617         __le64                  journal_seq;
1618
1619         struct jset_entry       start[0];
1620         __u64                   _data[];
1621 };
1622
1623 struct journal_seq_blacklist_entry {
1624         __le64                  start;
1625         __le64                  end;
1626 };
1627
1628 struct bch_sb_field_journal_seq_blacklist {
1629         struct bch_sb_field     field;
1630         struct journal_seq_blacklist_entry start[];
1631 };
1632
1633 struct bch_sb_field_errors {
1634         struct bch_sb_field     field;
1635         struct bch_sb_field_error_entry {
1636                 __le64          v;
1637                 __le64          last_error_time;
1638         }                       entries[];
1639 };
1640
1641 LE64_BITMASK(BCH_SB_ERROR_ENTRY_ID,     struct bch_sb_field_error_entry, v,  0, 16);
1642 LE64_BITMASK(BCH_SB_ERROR_ENTRY_NR,     struct bch_sb_field_error_entry, v, 16, 64);
1643
1644 /* Superblock: */
1645
1646 /*
1647  * New versioning scheme:
1648  * One common version number for all on disk data structures - superblock, btree
1649  * nodes, journal entries
1650  */
1651 #define BCH_VERSION_MAJOR(_v)           ((__u16) ((_v) >> 10))
1652 #define BCH_VERSION_MINOR(_v)           ((__u16) ((_v) & ~(~0U << 10)))
1653 #define BCH_VERSION(_major, _minor)     (((_major) << 10)|(_minor) << 0)
1654
1655 #define RECOVERY_PASS_ALL_FSCK          (1ULL << 63)
1656
1657 #define BCH_METADATA_VERSIONS()                                         \
1658         x(bkey_renumber,                BCH_VERSION(0, 10),             \
1659           RECOVERY_PASS_ALL_FSCK)                                       \
1660         x(inode_btree_change,           BCH_VERSION(0, 11),             \
1661           RECOVERY_PASS_ALL_FSCK)                                       \
1662         x(snapshot,                     BCH_VERSION(0, 12),             \
1663           RECOVERY_PASS_ALL_FSCK)                                       \
1664         x(inode_backpointers,           BCH_VERSION(0, 13),             \
1665           RECOVERY_PASS_ALL_FSCK)                                       \
1666         x(btree_ptr_sectors_written,    BCH_VERSION(0, 14),             \
1667           RECOVERY_PASS_ALL_FSCK)                                       \
1668         x(snapshot_2,                   BCH_VERSION(0, 15),             \
1669           BIT_ULL(BCH_RECOVERY_PASS_fs_upgrade_for_subvolumes)|         \
1670           BIT_ULL(BCH_RECOVERY_PASS_initialize_subvolumes)|             \
1671           RECOVERY_PASS_ALL_FSCK)                                       \
1672         x(reflink_p_fix,                BCH_VERSION(0, 16),             \
1673           BIT_ULL(BCH_RECOVERY_PASS_fix_reflink_p))                     \
1674         x(subvol_dirent,                BCH_VERSION(0, 17),             \
1675           RECOVERY_PASS_ALL_FSCK)                                       \
1676         x(inode_v2,                     BCH_VERSION(0, 18),             \
1677           RECOVERY_PASS_ALL_FSCK)                                       \
1678         x(freespace,                    BCH_VERSION(0, 19),             \
1679           RECOVERY_PASS_ALL_FSCK)                                       \
1680         x(alloc_v4,                     BCH_VERSION(0, 20),             \
1681           RECOVERY_PASS_ALL_FSCK)                                       \
1682         x(new_data_types,               BCH_VERSION(0, 21),             \
1683           RECOVERY_PASS_ALL_FSCK)                                       \
1684         x(backpointers,                 BCH_VERSION(0, 22),             \
1685           RECOVERY_PASS_ALL_FSCK)                                       \
1686         x(inode_v3,                     BCH_VERSION(0, 23),             \
1687           RECOVERY_PASS_ALL_FSCK)                                       \
1688         x(unwritten_extents,            BCH_VERSION(0, 24),             \
1689           RECOVERY_PASS_ALL_FSCK)                                       \
1690         x(bucket_gens,                  BCH_VERSION(0, 25),             \
1691           BIT_ULL(BCH_RECOVERY_PASS_bucket_gens_init)|                  \
1692           RECOVERY_PASS_ALL_FSCK)                                       \
1693         x(lru_v2,                       BCH_VERSION(0, 26),             \
1694           RECOVERY_PASS_ALL_FSCK)                                       \
1695         x(fragmentation_lru,            BCH_VERSION(0, 27),             \
1696           RECOVERY_PASS_ALL_FSCK)                                       \
1697         x(no_bps_in_alloc_keys,         BCH_VERSION(0, 28),             \
1698           RECOVERY_PASS_ALL_FSCK)                                       \
1699         x(snapshot_trees,               BCH_VERSION(0, 29),             \
1700           RECOVERY_PASS_ALL_FSCK)                                       \
1701         x(major_minor,                  BCH_VERSION(1,  0),             \
1702           0)                                                            \
1703         x(snapshot_skiplists,           BCH_VERSION(1,  1),             \
1704           BIT_ULL(BCH_RECOVERY_PASS_check_snapshots))                   \
1705         x(deleted_inodes,               BCH_VERSION(1,  2),             \
1706           BIT_ULL(BCH_RECOVERY_PASS_check_inodes))                      \
1707         x(rebalance_work,               BCH_VERSION(1,  3),             \
1708           BIT_ULL(BCH_RECOVERY_PASS_set_fs_needs_rebalance))            \
1709         x(member_seq,                   BCH_VERSION(1,  4),             \
1710           0)
1711
1712 enum bcachefs_metadata_version {
1713         bcachefs_metadata_version_min = 9,
1714 #define x(t, n, upgrade_passes) bcachefs_metadata_version_##t = n,
1715         BCH_METADATA_VERSIONS()
1716 #undef x
1717         bcachefs_metadata_version_max
1718 };
1719
1720 static const __maybe_unused
1721 unsigned bcachefs_metadata_required_upgrade_below = bcachefs_metadata_version_rebalance_work;
1722
1723 #define bcachefs_metadata_version_current       (bcachefs_metadata_version_max - 1)
1724
1725 #define BCH_SB_SECTOR                   8
1726 #define BCH_SB_MEMBERS_MAX              64 /* XXX kill */
1727
1728 struct bch_sb_layout {
1729         __uuid_t                magic;  /* bcachefs superblock UUID */
1730         __u8                    layout_type;
1731         __u8                    sb_max_size_bits; /* base 2 of 512 byte sectors */
1732         __u8                    nr_superblocks;
1733         __u8                    pad[5];
1734         __le64                  sb_offset[61];
1735 } __packed __aligned(8);
1736
1737 #define BCH_SB_LAYOUT_SECTOR    7
1738
1739 /*
1740  * @offset      - sector where this sb was written
1741  * @version     - on disk format version
1742  * @version_min - Oldest metadata version this filesystem contains; so we can
1743  *                safely drop compatibility code and refuse to mount filesystems
1744  *                we'd need it for
1745  * @magic       - identifies as a bcachefs superblock (BCHFS_MAGIC)
1746  * @seq         - incremented each time superblock is written
1747  * @uuid        - used for generating various magic numbers and identifying
1748  *                member devices, never changes
1749  * @user_uuid   - user visible UUID, may be changed
1750  * @label       - filesystem label
1751  * @seq         - identifies most recent superblock, incremented each time
1752  *                superblock is written
1753  * @features    - enabled incompatible features
1754  */
1755 struct bch_sb {
1756         struct bch_csum         csum;
1757         __le16                  version;
1758         __le16                  version_min;
1759         __le16                  pad[2];
1760         __uuid_t                magic;
1761         __uuid_t                uuid;
1762         __uuid_t                user_uuid;
1763         __u8                    label[BCH_SB_LABEL_SIZE];
1764         __le64                  offset;
1765         __le64                  seq;
1766
1767         __le16                  block_size;
1768         __u8                    dev_idx;
1769         __u8                    nr_devices;
1770         __le32                  u64s;
1771
1772         __le64                  time_base_lo;
1773         __le32                  time_base_hi;
1774         __le32                  time_precision;
1775
1776         __le64                  flags[7];
1777         __le64                  write_time;
1778         __le64                  features[2];
1779         __le64                  compat[2];
1780
1781         struct bch_sb_layout    layout;
1782
1783         struct bch_sb_field     start[0];
1784         __le64                  _data[];
1785 } __packed __aligned(8);
1786
1787 /*
1788  * Flags:
1789  * BCH_SB_INITALIZED    - set on first mount
1790  * BCH_SB_CLEAN         - did we shut down cleanly? Just a hint, doesn't affect
1791  *                        behaviour of mount/recovery path:
1792  * BCH_SB_INODE_32BIT   - limit inode numbers to 32 bits
1793  * BCH_SB_128_BIT_MACS  - 128 bit macs instead of 80
1794  * BCH_SB_ENCRYPTION_TYPE - if nonzero encryption is enabled; overrides
1795  *                         DATA/META_CSUM_TYPE. Also indicates encryption
1796  *                         algorithm in use, if/when we get more than one
1797  */
1798
1799 LE16_BITMASK(BCH_SB_BLOCK_SIZE,         struct bch_sb, block_size, 0, 16);
1800
1801 LE64_BITMASK(BCH_SB_INITIALIZED,        struct bch_sb, flags[0],  0,  1);
1802 LE64_BITMASK(BCH_SB_CLEAN,              struct bch_sb, flags[0],  1,  2);
1803 LE64_BITMASK(BCH_SB_CSUM_TYPE,          struct bch_sb, flags[0],  2,  8);
1804 LE64_BITMASK(BCH_SB_ERROR_ACTION,       struct bch_sb, flags[0],  8, 12);
1805
1806 LE64_BITMASK(BCH_SB_BTREE_NODE_SIZE,    struct bch_sb, flags[0], 12, 28);
1807
1808 LE64_BITMASK(BCH_SB_GC_RESERVE,         struct bch_sb, flags[0], 28, 33);
1809 LE64_BITMASK(BCH_SB_ROOT_RESERVE,       struct bch_sb, flags[0], 33, 40);
1810
1811 LE64_BITMASK(BCH_SB_META_CSUM_TYPE,     struct bch_sb, flags[0], 40, 44);
1812 LE64_BITMASK(BCH_SB_DATA_CSUM_TYPE,     struct bch_sb, flags[0], 44, 48);
1813
1814 LE64_BITMASK(BCH_SB_META_REPLICAS_WANT, struct bch_sb, flags[0], 48, 52);
1815 LE64_BITMASK(BCH_SB_DATA_REPLICAS_WANT, struct bch_sb, flags[0], 52, 56);
1816
1817 LE64_BITMASK(BCH_SB_POSIX_ACL,          struct bch_sb, flags[0], 56, 57);
1818 LE64_BITMASK(BCH_SB_USRQUOTA,           struct bch_sb, flags[0], 57, 58);
1819 LE64_BITMASK(BCH_SB_GRPQUOTA,           struct bch_sb, flags[0], 58, 59);
1820 LE64_BITMASK(BCH_SB_PRJQUOTA,           struct bch_sb, flags[0], 59, 60);
1821
1822 LE64_BITMASK(BCH_SB_HAS_ERRORS,         struct bch_sb, flags[0], 60, 61);
1823 LE64_BITMASK(BCH_SB_HAS_TOPOLOGY_ERRORS,struct bch_sb, flags[0], 61, 62);
1824
1825 LE64_BITMASK(BCH_SB_BIG_ENDIAN,         struct bch_sb, flags[0], 62, 63);
1826
1827 LE64_BITMASK(BCH_SB_STR_HASH_TYPE,      struct bch_sb, flags[1],  0,  4);
1828 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_LO,struct bch_sb, flags[1],  4,  8);
1829 LE64_BITMASK(BCH_SB_INODE_32BIT,        struct bch_sb, flags[1],  8,  9);
1830
1831 LE64_BITMASK(BCH_SB_128_BIT_MACS,       struct bch_sb, flags[1],  9, 10);
1832 LE64_BITMASK(BCH_SB_ENCRYPTION_TYPE,    struct bch_sb, flags[1], 10, 14);
1833
1834 /*
1835  * Max size of an extent that may require bouncing to read or write
1836  * (checksummed, compressed): 64k
1837  */
1838 LE64_BITMASK(BCH_SB_ENCODED_EXTENT_MAX_BITS,
1839                                         struct bch_sb, flags[1], 14, 20);
1840
1841 LE64_BITMASK(BCH_SB_META_REPLICAS_REQ,  struct bch_sb, flags[1], 20, 24);
1842 LE64_BITMASK(BCH_SB_DATA_REPLICAS_REQ,  struct bch_sb, flags[1], 24, 28);
1843
1844 LE64_BITMASK(BCH_SB_PROMOTE_TARGET,     struct bch_sb, flags[1], 28, 40);
1845 LE64_BITMASK(BCH_SB_FOREGROUND_TARGET,  struct bch_sb, flags[1], 40, 52);
1846 LE64_BITMASK(BCH_SB_BACKGROUND_TARGET,  struct bch_sb, flags[1], 52, 64);
1847
1848 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO,
1849                                         struct bch_sb, flags[2],  0,  4);
1850 LE64_BITMASK(BCH_SB_GC_RESERVE_BYTES,   struct bch_sb, flags[2],  4, 64);
1851
1852 LE64_BITMASK(BCH_SB_ERASURE_CODE,       struct bch_sb, flags[3],  0, 16);
1853 LE64_BITMASK(BCH_SB_METADATA_TARGET,    struct bch_sb, flags[3], 16, 28);
1854 LE64_BITMASK(BCH_SB_SHARD_INUMS,        struct bch_sb, flags[3], 28, 29);
1855 LE64_BITMASK(BCH_SB_INODES_USE_KEY_CACHE,struct bch_sb, flags[3], 29, 30);
1856 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DELAY,struct bch_sb, flags[3], 30, 62);
1857 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DISABLED,struct bch_sb, flags[3], 62, 63);
1858 LE64_BITMASK(BCH_SB_JOURNAL_RECLAIM_DELAY,struct bch_sb, flags[4], 0, 32);
1859 LE64_BITMASK(BCH_SB_JOURNAL_TRANSACTION_NAMES,struct bch_sb, flags[4], 32, 33);
1860 LE64_BITMASK(BCH_SB_NOCOW,              struct bch_sb, flags[4], 33, 34);
1861 LE64_BITMASK(BCH_SB_WRITE_BUFFER_SIZE,  struct bch_sb, flags[4], 34, 54);
1862 LE64_BITMASK(BCH_SB_VERSION_UPGRADE,    struct bch_sb, flags[4], 54, 56);
1863
1864 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_HI,struct bch_sb, flags[4], 56, 60);
1865 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI,
1866                                         struct bch_sb, flags[4], 60, 64);
1867
1868 LE64_BITMASK(BCH_SB_VERSION_UPGRADE_COMPLETE,
1869                                         struct bch_sb, flags[5],  0, 16);
1870
1871 static inline __u64 BCH_SB_COMPRESSION_TYPE(const struct bch_sb *sb)
1872 {
1873         return BCH_SB_COMPRESSION_TYPE_LO(sb) | (BCH_SB_COMPRESSION_TYPE_HI(sb) << 4);
1874 }
1875
1876 static inline void SET_BCH_SB_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1877 {
1878         SET_BCH_SB_COMPRESSION_TYPE_LO(sb, v);
1879         SET_BCH_SB_COMPRESSION_TYPE_HI(sb, v >> 4);
1880 }
1881
1882 static inline __u64 BCH_SB_BACKGROUND_COMPRESSION_TYPE(const struct bch_sb *sb)
1883 {
1884         return BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb) |
1885                 (BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb) << 4);
1886 }
1887
1888 static inline void SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1889 {
1890         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb, v);
1891         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb, v >> 4);
1892 }
1893
1894 /*
1895  * Features:
1896  *
1897  * journal_seq_blacklist_v3:    gates BCH_SB_FIELD_journal_seq_blacklist
1898  * reflink:                     gates KEY_TYPE_reflink
1899  * inline_data:                 gates KEY_TYPE_inline_data
1900  * new_siphash:                 gates BCH_STR_HASH_siphash
1901  * new_extent_overwrite:        gates BTREE_NODE_NEW_EXTENT_OVERWRITE
1902  */
1903 #define BCH_SB_FEATURES()                       \
1904         x(lz4,                          0)      \
1905         x(gzip,                         1)      \
1906         x(zstd,                         2)      \
1907         x(atomic_nlink,                 3)      \
1908         x(ec,                           4)      \
1909         x(journal_seq_blacklist_v3,     5)      \
1910         x(reflink,                      6)      \
1911         x(new_siphash,                  7)      \
1912         x(inline_data,                  8)      \
1913         x(new_extent_overwrite,         9)      \
1914         x(incompressible,               10)     \
1915         x(btree_ptr_v2,                 11)     \
1916         x(extents_above_btree_updates,  12)     \
1917         x(btree_updates_journalled,     13)     \
1918         x(reflink_inline_data,          14)     \
1919         x(new_varint,                   15)     \
1920         x(journal_no_flush,             16)     \
1921         x(alloc_v2,                     17)     \
1922         x(extents_across_btree_nodes,   18)
1923
1924 #define BCH_SB_FEATURES_ALWAYS                          \
1925         ((1ULL << BCH_FEATURE_new_extent_overwrite)|    \
1926          (1ULL << BCH_FEATURE_extents_above_btree_updates)|\
1927          (1ULL << BCH_FEATURE_btree_updates_journalled)|\
1928          (1ULL << BCH_FEATURE_alloc_v2)|\
1929          (1ULL << BCH_FEATURE_extents_across_btree_nodes))
1930
1931 #define BCH_SB_FEATURES_ALL                             \
1932         (BCH_SB_FEATURES_ALWAYS|                        \
1933          (1ULL << BCH_FEATURE_new_siphash)|             \
1934          (1ULL << BCH_FEATURE_btree_ptr_v2)|            \
1935          (1ULL << BCH_FEATURE_new_varint)|              \
1936          (1ULL << BCH_FEATURE_journal_no_flush))
1937
1938 enum bch_sb_feature {
1939 #define x(f, n) BCH_FEATURE_##f,
1940         BCH_SB_FEATURES()
1941 #undef x
1942         BCH_FEATURE_NR,
1943 };
1944
1945 #define BCH_SB_COMPAT()                                 \
1946         x(alloc_info,                           0)      \
1947         x(alloc_metadata,                       1)      \
1948         x(extents_above_btree_updates_done,     2)      \
1949         x(bformat_overflow_done,                3)
1950
1951 enum bch_sb_compat {
1952 #define x(f, n) BCH_COMPAT_##f,
1953         BCH_SB_COMPAT()
1954 #undef x
1955         BCH_COMPAT_NR,
1956 };
1957
1958 /* options: */
1959
1960 #define BCH_VERSION_UPGRADE_OPTS()      \
1961         x(compatible,           0)      \
1962         x(incompatible,         1)      \
1963         x(none,                 2)
1964
1965 enum bch_version_upgrade_opts {
1966 #define x(t, n) BCH_VERSION_UPGRADE_##t = n,
1967         BCH_VERSION_UPGRADE_OPTS()
1968 #undef x
1969 };
1970
1971 #define BCH_REPLICAS_MAX                4U
1972
1973 #define BCH_BKEY_PTRS_MAX               16U
1974
1975 #define BCH_ERROR_ACTIONS()             \
1976         x(continue,             0)      \
1977         x(ro,                   1)      \
1978         x(panic,                2)
1979
1980 enum bch_error_actions {
1981 #define x(t, n) BCH_ON_ERROR_##t = n,
1982         BCH_ERROR_ACTIONS()
1983 #undef x
1984         BCH_ON_ERROR_NR
1985 };
1986
1987 #define BCH_STR_HASH_TYPES()            \
1988         x(crc32c,               0)      \
1989         x(crc64,                1)      \
1990         x(siphash_old,          2)      \
1991         x(siphash,              3)
1992
1993 enum bch_str_hash_type {
1994 #define x(t, n) BCH_STR_HASH_##t = n,
1995         BCH_STR_HASH_TYPES()
1996 #undef x
1997         BCH_STR_HASH_NR
1998 };
1999
2000 #define BCH_STR_HASH_OPTS()             \
2001         x(crc32c,               0)      \
2002         x(crc64,                1)      \
2003         x(siphash,              2)
2004
2005 enum bch_str_hash_opts {
2006 #define x(t, n) BCH_STR_HASH_OPT_##t = n,
2007         BCH_STR_HASH_OPTS()
2008 #undef x
2009         BCH_STR_HASH_OPT_NR
2010 };
2011
2012 #define BCH_CSUM_TYPES()                        \
2013         x(none,                         0)      \
2014         x(crc32c_nonzero,               1)      \
2015         x(crc64_nonzero,                2)      \
2016         x(chacha20_poly1305_80,         3)      \
2017         x(chacha20_poly1305_128,        4)      \
2018         x(crc32c,                       5)      \
2019         x(crc64,                        6)      \
2020         x(xxhash,                       7)
2021
2022 enum bch_csum_type {
2023 #define x(t, n) BCH_CSUM_##t = n,
2024         BCH_CSUM_TYPES()
2025 #undef x
2026         BCH_CSUM_NR
2027 };
2028
2029 static const __maybe_unused unsigned bch_crc_bytes[] = {
2030         [BCH_CSUM_none]                         = 0,
2031         [BCH_CSUM_crc32c_nonzero]               = 4,
2032         [BCH_CSUM_crc32c]                       = 4,
2033         [BCH_CSUM_crc64_nonzero]                = 8,
2034         [BCH_CSUM_crc64]                        = 8,
2035         [BCH_CSUM_xxhash]                       = 8,
2036         [BCH_CSUM_chacha20_poly1305_80]         = 10,
2037         [BCH_CSUM_chacha20_poly1305_128]        = 16,
2038 };
2039
2040 static inline _Bool bch2_csum_type_is_encryption(enum bch_csum_type type)
2041 {
2042         switch (type) {
2043         case BCH_CSUM_chacha20_poly1305_80:
2044         case BCH_CSUM_chacha20_poly1305_128:
2045                 return true;
2046         default:
2047                 return false;
2048         }
2049 }
2050
2051 #define BCH_CSUM_OPTS()                 \
2052         x(none,                 0)      \
2053         x(crc32c,               1)      \
2054         x(crc64,                2)      \
2055         x(xxhash,               3)
2056
2057 enum bch_csum_opts {
2058 #define x(t, n) BCH_CSUM_OPT_##t = n,
2059         BCH_CSUM_OPTS()
2060 #undef x
2061         BCH_CSUM_OPT_NR
2062 };
2063
2064 #define BCH_COMPRESSION_TYPES()         \
2065         x(none,                 0)      \
2066         x(lz4_old,              1)      \
2067         x(gzip,                 2)      \
2068         x(lz4,                  3)      \
2069         x(zstd,                 4)      \
2070         x(incompressible,       5)
2071
2072 enum bch_compression_type {
2073 #define x(t, n) BCH_COMPRESSION_TYPE_##t = n,
2074         BCH_COMPRESSION_TYPES()
2075 #undef x
2076         BCH_COMPRESSION_TYPE_NR
2077 };
2078
2079 #define BCH_COMPRESSION_OPTS()          \
2080         x(none,         0)              \
2081         x(lz4,          1)              \
2082         x(gzip,         2)              \
2083         x(zstd,         3)
2084
2085 enum bch_compression_opts {
2086 #define x(t, n) BCH_COMPRESSION_OPT_##t = n,
2087         BCH_COMPRESSION_OPTS()
2088 #undef x
2089         BCH_COMPRESSION_OPT_NR
2090 };
2091
2092 /*
2093  * Magic numbers
2094  *
2095  * The various other data structures have their own magic numbers, which are
2096  * xored with the first part of the cache set's UUID
2097  */
2098
2099 #define BCACHE_MAGIC                                                    \
2100         UUID_INIT(0xc68573f6, 0x4e1a, 0x45ca,                           \
2101                   0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81)
2102 #define BCHFS_MAGIC                                                     \
2103         UUID_INIT(0xc68573f6, 0x66ce, 0x90a9,                           \
2104                   0xd9, 0x6a, 0x60, 0xcf, 0x80, 0x3d, 0xf7, 0xef)
2105
2106 #define BCACHEFS_STATFS_MAGIC           0xca451a4e
2107
2108 #define JSET_MAGIC              __cpu_to_le64(0x245235c1a3625032ULL)
2109 #define BSET_MAGIC              __cpu_to_le64(0x90135c78b99e07f5ULL)
2110
2111 static inline __le64 __bch2_sb_magic(struct bch_sb *sb)
2112 {
2113         __le64 ret;
2114
2115         memcpy(&ret, &sb->uuid, sizeof(ret));
2116         return ret;
2117 }
2118
2119 static inline __u64 __jset_magic(struct bch_sb *sb)
2120 {
2121         return __le64_to_cpu(__bch2_sb_magic(sb) ^ JSET_MAGIC);
2122 }
2123
2124 static inline __u64 __bset_magic(struct bch_sb *sb)
2125 {
2126         return __le64_to_cpu(__bch2_sb_magic(sb) ^ BSET_MAGIC);
2127 }
2128
2129 /* Journal */
2130
2131 #define JSET_KEYS_U64s  (sizeof(struct jset_entry) / sizeof(__u64))
2132
2133 #define BCH_JSET_ENTRY_TYPES()                  \
2134         x(btree_keys,           0)              \
2135         x(btree_root,           1)              \
2136         x(prio_ptrs,            2)              \
2137         x(blacklist,            3)              \
2138         x(blacklist_v2,         4)              \
2139         x(usage,                5)              \
2140         x(data_usage,           6)              \
2141         x(clock,                7)              \
2142         x(dev_usage,            8)              \
2143         x(log,                  9)              \
2144         x(overwrite,            10)             \
2145         x(write_buffer_keys,    11)
2146
2147 enum {
2148 #define x(f, nr)        BCH_JSET_ENTRY_##f      = nr,
2149         BCH_JSET_ENTRY_TYPES()
2150 #undef x
2151         BCH_JSET_ENTRY_NR
2152 };
2153
2154 static inline bool jset_entry_is_key(struct jset_entry *e)
2155 {
2156         switch (e->type) {
2157         case BCH_JSET_ENTRY_btree_keys:
2158         case BCH_JSET_ENTRY_btree_root:
2159         case BCH_JSET_ENTRY_overwrite:
2160         case BCH_JSET_ENTRY_write_buffer_keys:
2161                 return true;
2162         }
2163
2164         return false;
2165 }
2166
2167 /*
2168  * Journal sequence numbers can be blacklisted: bsets record the max sequence
2169  * number of all the journal entries they contain updates for, so that on
2170  * recovery we can ignore those bsets that contain index updates newer that what
2171  * made it into the journal.
2172  *
2173  * This means that we can't reuse that journal_seq - we have to skip it, and
2174  * then record that we skipped it so that the next time we crash and recover we
2175  * don't think there was a missing journal entry.
2176  */
2177 struct jset_entry_blacklist {
2178         struct jset_entry       entry;
2179         __le64                  seq;
2180 };
2181
2182 struct jset_entry_blacklist_v2 {
2183         struct jset_entry       entry;
2184         __le64                  start;
2185         __le64                  end;
2186 };
2187
2188 #define BCH_FS_USAGE_TYPES()                    \
2189         x(reserved,             0)              \
2190         x(inodes,               1)              \
2191         x(key_version,          2)
2192
2193 enum {
2194 #define x(f, nr)        BCH_FS_USAGE_##f        = nr,
2195         BCH_FS_USAGE_TYPES()
2196 #undef x
2197         BCH_FS_USAGE_NR
2198 };
2199
2200 struct jset_entry_usage {
2201         struct jset_entry       entry;
2202         __le64                  v;
2203 } __packed;
2204
2205 struct jset_entry_data_usage {
2206         struct jset_entry       entry;
2207         __le64                  v;
2208         struct bch_replicas_entry_v1 r;
2209 } __packed;
2210
2211 struct jset_entry_clock {
2212         struct jset_entry       entry;
2213         __u8                    rw;
2214         __u8                    pad[7];
2215         __le64                  time;
2216 } __packed;
2217
2218 struct jset_entry_dev_usage_type {
2219         __le64                  buckets;
2220         __le64                  sectors;
2221         __le64                  fragmented;
2222 } __packed;
2223
2224 struct jset_entry_dev_usage {
2225         struct jset_entry       entry;
2226         __le32                  dev;
2227         __u32                   pad;
2228
2229         __le64                  _buckets_ec;            /* No longer used */
2230         __le64                  _buckets_unavailable;   /* No longer used */
2231
2232         struct jset_entry_dev_usage_type d[];
2233 };
2234
2235 static inline unsigned jset_entry_dev_usage_nr_types(struct jset_entry_dev_usage *u)
2236 {
2237         return (vstruct_bytes(&u->entry) - sizeof(struct jset_entry_dev_usage)) /
2238                 sizeof(struct jset_entry_dev_usage_type);
2239 }
2240
2241 struct jset_entry_log {
2242         struct jset_entry       entry;
2243         u8                      d[];
2244 } __packed __aligned(8);
2245
2246 /*
2247  * On disk format for a journal entry:
2248  * seq is monotonically increasing; every journal entry has its own unique
2249  * sequence number.
2250  *
2251  * last_seq is the oldest journal entry that still has keys the btree hasn't
2252  * flushed to disk yet.
2253  *
2254  * version is for on disk format changes.
2255  */
2256 struct jset {
2257         struct bch_csum         csum;
2258
2259         __le64                  magic;
2260         __le64                  seq;
2261         __le32                  version;
2262         __le32                  flags;
2263
2264         __le32                  u64s; /* size of d[] in u64s */
2265
2266         __u8                    encrypted_start[0];
2267
2268         __le16                  _read_clock; /* no longer used */
2269         __le16                  _write_clock;
2270
2271         /* Sequence number of oldest dirty journal entry */
2272         __le64                  last_seq;
2273
2274
2275         struct jset_entry       start[0];
2276         __u64                   _data[];
2277 } __packed __aligned(8);
2278
2279 LE32_BITMASK(JSET_CSUM_TYPE,    struct jset, flags, 0, 4);
2280 LE32_BITMASK(JSET_BIG_ENDIAN,   struct jset, flags, 4, 5);
2281 LE32_BITMASK(JSET_NO_FLUSH,     struct jset, flags, 5, 6);
2282
2283 #define BCH_JOURNAL_BUCKETS_MIN         8
2284
2285 /* Btree: */
2286
2287 enum btree_id_flags {
2288         BTREE_ID_EXTENTS        = BIT(0),
2289         BTREE_ID_SNAPSHOTS      = BIT(1),
2290         BTREE_ID_SNAPSHOT_FIELD = BIT(2),
2291         BTREE_ID_DATA           = BIT(3),
2292 };
2293
2294 #define BCH_BTREE_IDS()                                                         \
2295         x(extents,              0,      BTREE_ID_EXTENTS|BTREE_ID_SNAPSHOTS|BTREE_ID_DATA,\
2296           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2297           BIT_ULL(KEY_TYPE_error)|                                              \
2298           BIT_ULL(KEY_TYPE_cookie)|                                             \
2299           BIT_ULL(KEY_TYPE_extent)|                                             \
2300           BIT_ULL(KEY_TYPE_reservation)|                                        \
2301           BIT_ULL(KEY_TYPE_reflink_p)|                                          \
2302           BIT_ULL(KEY_TYPE_inline_data))                                        \
2303         x(inodes,               1,      BTREE_ID_SNAPSHOTS,                     \
2304           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2305           BIT_ULL(KEY_TYPE_inode)|                                              \
2306           BIT_ULL(KEY_TYPE_inode_v2)|                                           \
2307           BIT_ULL(KEY_TYPE_inode_v3)|                                           \
2308           BIT_ULL(KEY_TYPE_inode_generation))                                   \
2309         x(dirents,              2,      BTREE_ID_SNAPSHOTS,                     \
2310           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2311           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
2312           BIT_ULL(KEY_TYPE_dirent))                                             \
2313         x(xattrs,               3,      BTREE_ID_SNAPSHOTS,                     \
2314           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2315           BIT_ULL(KEY_TYPE_cookie)|                                             \
2316           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
2317           BIT_ULL(KEY_TYPE_xattr))                                              \
2318         x(alloc,                4,      0,                                      \
2319           BIT_ULL(KEY_TYPE_alloc)|                                              \
2320           BIT_ULL(KEY_TYPE_alloc_v2)|                                           \
2321           BIT_ULL(KEY_TYPE_alloc_v3)|                                           \
2322           BIT_ULL(KEY_TYPE_alloc_v4))                                           \
2323         x(quotas,               5,      0,                                      \
2324           BIT_ULL(KEY_TYPE_quota))                                              \
2325         x(stripes,              6,      0,                                      \
2326           BIT_ULL(KEY_TYPE_stripe))                                             \
2327         x(reflink,              7,      BTREE_ID_EXTENTS|BTREE_ID_DATA,         \
2328           BIT_ULL(KEY_TYPE_reflink_v)|                                          \
2329           BIT_ULL(KEY_TYPE_indirect_inline_data))                               \
2330         x(subvolumes,           8,      0,                                      \
2331           BIT_ULL(KEY_TYPE_subvolume))                                          \
2332         x(snapshots,            9,      0,                                      \
2333           BIT_ULL(KEY_TYPE_snapshot))                                           \
2334         x(lru,                  10,     0,                                      \
2335           BIT_ULL(KEY_TYPE_set))                                                \
2336         x(freespace,            11,     BTREE_ID_EXTENTS,                       \
2337           BIT_ULL(KEY_TYPE_set))                                                \
2338         x(need_discard,         12,     0,                                      \
2339           BIT_ULL(KEY_TYPE_set))                                                \
2340         x(backpointers,         13,     0,                                      \
2341           BIT_ULL(KEY_TYPE_backpointer))                                        \
2342         x(bucket_gens,          14,     0,                                      \
2343           BIT_ULL(KEY_TYPE_bucket_gens))                                        \
2344         x(snapshot_trees,       15,     0,                                      \
2345           BIT_ULL(KEY_TYPE_snapshot_tree))                                      \
2346         x(deleted_inodes,       16,     BTREE_ID_SNAPSHOT_FIELD,                \
2347           BIT_ULL(KEY_TYPE_set))                                                \
2348         x(logged_ops,           17,     0,                                      \
2349           BIT_ULL(KEY_TYPE_logged_op_truncate)|                                 \
2350           BIT_ULL(KEY_TYPE_logged_op_finsert))                                  \
2351         x(rebalance_work,       18,     BTREE_ID_SNAPSHOT_FIELD,                \
2352           BIT_ULL(KEY_TYPE_set)|BIT_ULL(KEY_TYPE_cookie))
2353
2354 enum btree_id {
2355 #define x(name, nr, ...) BTREE_ID_##name = nr,
2356         BCH_BTREE_IDS()
2357 #undef x
2358         BTREE_ID_NR
2359 };
2360
2361 #define BTREE_MAX_DEPTH         4U
2362
2363 /* Btree nodes */
2364
2365 /*
2366  * Btree nodes
2367  *
2368  * On disk a btree node is a list/log of these; within each set the keys are
2369  * sorted
2370  */
2371 struct bset {
2372         __le64                  seq;
2373
2374         /*
2375          * Highest journal entry this bset contains keys for.
2376          * If on recovery we don't see that journal entry, this bset is ignored:
2377          * this allows us to preserve the order of all index updates after a
2378          * crash, since the journal records a total order of all index updates
2379          * and anything that didn't make it to the journal doesn't get used.
2380          */
2381         __le64                  journal_seq;
2382
2383         __le32                  flags;
2384         __le16                  version;
2385         __le16                  u64s; /* count of d[] in u64s */
2386
2387         struct bkey_packed      start[0];
2388         __u64                   _data[];
2389 } __packed __aligned(8);
2390
2391 LE32_BITMASK(BSET_CSUM_TYPE,    struct bset, flags, 0, 4);
2392
2393 LE32_BITMASK(BSET_BIG_ENDIAN,   struct bset, flags, 4, 5);
2394 LE32_BITMASK(BSET_SEPARATE_WHITEOUTS,
2395                                 struct bset, flags, 5, 6);
2396
2397 /* Sector offset within the btree node: */
2398 LE32_BITMASK(BSET_OFFSET,       struct bset, flags, 16, 32);
2399
2400 struct btree_node {
2401         struct bch_csum         csum;
2402         __le64                  magic;
2403
2404         /* this flags field is encrypted, unlike bset->flags: */
2405         __le64                  flags;
2406
2407         /* Closed interval: */
2408         struct bpos             min_key;
2409         struct bpos             max_key;
2410         struct bch_extent_ptr   _ptr; /* not used anymore */
2411         struct bkey_format      format;
2412
2413         union {
2414         struct bset             keys;
2415         struct {
2416                 __u8            pad[22];
2417                 __le16          u64s;
2418                 __u64           _data[0];
2419
2420         };
2421         };
2422 } __packed __aligned(8);
2423
2424 LE64_BITMASK(BTREE_NODE_ID_LO,  struct btree_node, flags,  0,  4);
2425 LE64_BITMASK(BTREE_NODE_LEVEL,  struct btree_node, flags,  4,  8);
2426 LE64_BITMASK(BTREE_NODE_NEW_EXTENT_OVERWRITE,
2427                                 struct btree_node, flags,  8,  9);
2428 LE64_BITMASK(BTREE_NODE_ID_HI,  struct btree_node, flags,  9, 25);
2429 /* 25-32 unused */
2430 LE64_BITMASK(BTREE_NODE_SEQ,    struct btree_node, flags, 32, 64);
2431
2432 static inline __u64 BTREE_NODE_ID(struct btree_node *n)
2433 {
2434         return BTREE_NODE_ID_LO(n) | (BTREE_NODE_ID_HI(n) << 4);
2435 }
2436
2437 static inline void SET_BTREE_NODE_ID(struct btree_node *n, __u64 v)
2438 {
2439         SET_BTREE_NODE_ID_LO(n, v);
2440         SET_BTREE_NODE_ID_HI(n, v >> 4);
2441 }
2442
2443 struct btree_node_entry {
2444         struct bch_csum         csum;
2445
2446         union {
2447         struct bset             keys;
2448         struct {
2449                 __u8            pad[22];
2450                 __le16          u64s;
2451                 __u64           _data[0];
2452         };
2453         };
2454 } __packed __aligned(8);
2455
2456 #endif /* _BCACHEFS_FORMAT_H */