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 __aligned(4);
 155
 156 #define KEY_INODE_MAX                   ((__u64)~0ULL)
 157 #define KEY_OFFSET_MAX                  ((__u64)~0ULL)
 158 #define KEY_SNAPSHOT_MAX                ((__u32)~0U)
 159 #define KEY_SIZE_MAX                    ((__u32)~0U)
 160
 161 static inline struct bpos SPOS(__u64 inode, __u64 offset, __u32 snapshot)
 162 {
 163         return (struct bpos) {
 164                 .inode          = inode,
 165                 .offset         = offset,
 166                 .snapshot       = snapshot,
 167         };
 168 }
 169
 170 #define POS_MIN                         SPOS(0, 0, 0)
 171 #define POS_MAX                         SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, 0)
 172 #define SPOS_MAX                        SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, KEY_SNAPSHOT_MAX)
 173 #define POS(_inode, _offset)            SPOS(_inode, _offset, 0)
 174
 175 /* Empty placeholder struct, for container_of() */
 176 struct bch_val {
 177         __u64           __nothing[0];
 178 };
 179
 180 struct bversion {
 181 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 182         __u64           lo;
 183         __u32           hi;
 184 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 185         __u32           hi;
 186         __u64           lo;
 187 #endif
 188 } __packed __aligned(4);
 189
 190 struct bkey {
 191         /* Size of combined key and value, in u64s */
 192         __u8            u64s;
 193
 194         /* Format of key (0 for format local to btree node) */
 195 #if defined(__LITTLE_ENDIAN_BITFIELD)
 196         __u8            format:7,
 197                         needs_whiteout:1;
 198 #elif defined (__BIG_ENDIAN_BITFIELD)
 199         __u8            needs_whiteout:1,
 200                         format:7;
 201 #else
 202 #error edit for your odd byteorder.
 203 #endif
 204
 205         /* Type of the value */
 206         __u8            type;
 207
 208 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 209         __u8            pad[1];
 210
 211         struct bversion version;
 212         __u32           size;           /* extent size, in sectors */
 213         struct bpos     p;
 214 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 215         struct bpos     p;
 216         __u32           size;           /* extent size, in sectors */
 217         struct bversion version;
 218
 219         __u8            pad[1];
 220 #endif
 221 } __packed __aligned(8);
 222
 223 struct bkey_packed {
 224         __u64           _data[0];
 225
 226         /* Size of combined key and value, in u64s */
 227         __u8            u64s;
 228
 229         /* Format of key (0 for format local to btree node) */
 230
 231         /*
 232          * XXX: next incompat on disk format change, switch format and
 233          * needs_whiteout - bkey_packed() will be cheaper if format is the high
 234          * bits of the bitfield
 235          */
 236 #if defined(__LITTLE_ENDIAN_BITFIELD)
 237         __u8            format:7,
 238                         needs_whiteout:1;
 239 #elif defined (__BIG_ENDIAN_BITFIELD)
 240         __u8            needs_whiteout:1,
 241                         format:7;
 242 #endif
 243
 244         /* Type of the value */
 245         __u8            type;
 246         __u8            key_start[0];
 247
 248         /*
 249          * We copy bkeys with struct assignment in various places, and while
 250          * that shouldn't be done with packed bkeys we can't disallow it in C,
 251          * and it's legal to cast a bkey to a bkey_packed  - so padding it out
 252          * to the same size as struct bkey should hopefully be safest.
 253          */
 254         __u8            pad[sizeof(struct bkey) - 3];
 255 } __packed __aligned(8);
 256
 257 typedef struct {
 258         __le64                  lo;
 259         __le64                  hi;
 260 } bch_le128;
 261
 262 #define BKEY_U64s                       (sizeof(struct bkey) / sizeof(__u64))
 263 #define BKEY_U64s_MAX                   U8_MAX
 264 #define BKEY_VAL_U64s_MAX               (BKEY_U64s_MAX - BKEY_U64s)
 265
 266 #define KEY_PACKED_BITS_START           24
 267
 268 #define KEY_FORMAT_LOCAL_BTREE          0
 269 #define KEY_FORMAT_CURRENT              1
 270
 271 enum bch_bkey_fields {
 272         BKEY_FIELD_INODE,
 273         BKEY_FIELD_OFFSET,
 274         BKEY_FIELD_SNAPSHOT,
 275         BKEY_FIELD_SIZE,
 276         BKEY_FIELD_VERSION_HI,
 277         BKEY_FIELD_VERSION_LO,
 278         BKEY_NR_FIELDS,
 279 };
 280
 281 #define bkey_format_field(name, field)                                  \
 282         [BKEY_FIELD_##name] = (sizeof(((struct bkey *) NULL)->field) * 8)
 283
 284 #define BKEY_FORMAT_CURRENT                                             \
 285 ((struct bkey_format) {                                                 \
 286         .key_u64s       = BKEY_U64s,                                    \
 287         .nr_fields      = BKEY_NR_FIELDS,                               \
 288         .bits_per_field = {                                             \
 289                 bkey_format_field(INODE,        p.inode),               \
 290                 bkey_format_field(OFFSET,       p.offset),              \
 291                 bkey_format_field(SNAPSHOT,     p.snapshot),            \
 292                 bkey_format_field(SIZE,         size),                  \
 293                 bkey_format_field(VERSION_HI,   version.hi),            \
 294                 bkey_format_field(VERSION_LO,   version.lo),            \
 295         },                                                              \
 296 })
 297
 298 /* bkey with inline value */
 299 struct bkey_i {
 300         __u64                   _data[0];
 301
 302         struct bkey     k;
 303         struct bch_val  v;
 304 };
 305
 306 #define KEY(_inode, _offset, _size)                                     \
 307 ((struct bkey) {                                                        \
 308         .u64s           = BKEY_U64s,                                    \
 309         .format         = KEY_FORMAT_CURRENT,                           \
 310         .p              = POS(_inode, _offset),                         \
 311         .size           = _size,                                        \
 312 })
 313
 314 static inline void bkey_init(struct bkey *k)
 315 {
 316         *k = KEY(0, 0, 0);
 317 }
 318
 319 #define bkey_bytes(_k)          ((_k)->u64s * sizeof(__u64))
 320
 321 #define __BKEY_PADDED(key, pad)                                 \
 322         struct bkey_i key; __u64 key ## _pad[pad]
 323
 324 /*
 325  * - DELETED keys are used internally to mark keys that should be ignored but
 326  *   override keys in composition order.  Their version number is ignored.
 327  *
 328  * - DISCARDED keys indicate that the data is all 0s because it has been
 329  *   discarded. DISCARDs may have a version; if the version is nonzero the key
 330  *   will be persistent, otherwise the key will be dropped whenever the btree
 331  *   node is rewritten (like DELETED keys).
 332  *
 333  * - ERROR: any read of the data returns a read error, as the data was lost due
 334  *   to a failing device. Like DISCARDED keys, they can be removed (overridden)
 335  *   by new writes or cluster-wide GC. Node repair can also overwrite them with
 336  *   the same or a more recent version number, but not with an older version
 337  *   number.
 338  *
 339  * - WHITEOUT: for hash table btrees
 340  */
 341 #define BCH_BKEY_TYPES()                                \
 342         x(deleted,              0)                      \
 343         x(whiteout,             1)                      \
 344         x(error,                2)                      \
 345         x(cookie,               3)                      \
 346         x(hash_whiteout,        4)                      \
 347         x(btree_ptr,            5)                      \
 348         x(extent,               6)                      \
 349         x(reservation,          7)                      \
 350         x(inode,                8)                      \
 351         x(inode_generation,     9)                      \
 352         x(dirent,               10)                     \
 353         x(xattr,                11)                     \
 354         x(alloc,                12)                     \
 355         x(quota,                13)                     \
 356         x(stripe,               14)                     \
 357         x(reflink_p,            15)                     \
 358         x(reflink_v,            16)                     \
 359         x(inline_data,          17)                     \
 360         x(btree_ptr_v2,         18)                     \
 361         x(indirect_inline_data, 19)                     \
 362         x(alloc_v2,             20)                     \
 363         x(subvolume,            21)                     \
 364         x(snapshot,             22)                     \
 365         x(inode_v2,             23)                     \
 366         x(alloc_v3,             24)                     \
 367         x(set,                  25)                     \
 368         x(lru,                  26)                     \
 369         x(alloc_v4,             27)                     \
 370         x(backpointer,          28)                     \
 371         x(inode_v3,             29)                     \
 372         x(bucket_gens,          30)                     \
 373         x(snapshot_tree,        31)                     \
 374         x(logged_op_truncate,   32)                     \
 375         x(logged_op_finsert,    33)
 376
 377 enum bch_bkey_type {
 378 #define x(name, nr) KEY_TYPE_##name     = nr,
 379         BCH_BKEY_TYPES()
 380 #undef x
 381         KEY_TYPE_MAX,
 382 };
 383
 384 struct bch_deleted {
 385         struct bch_val          v;
 386 };
 387
 388 struct bch_whiteout {
 389         struct bch_val          v;
 390 };
 391
 392 struct bch_error {
 393         struct bch_val          v;
 394 };
 395
 396 struct bch_cookie {
 397         struct bch_val          v;
 398         __le64                  cookie;
 399 };
 400
 401 struct bch_hash_whiteout {
 402         struct bch_val          v;
 403 };
 404
 405 struct bch_set {
 406         struct bch_val          v;
 407 };
 408
 409 /* Extents */
 410
 411 /*
 412  * In extent bkeys, the value is a list of pointers (bch_extent_ptr), optionally
 413  * preceded by checksum/compression information (bch_extent_crc32 or
 414  * bch_extent_crc64).
 415  *
 416  * One major determining factor in the format of extents is how we handle and
 417  * represent extents that have been partially overwritten and thus trimmed:
 418  *
 419  * If an extent is not checksummed or compressed, when the extent is trimmed we
 420  * don't have to remember the extent we originally allocated and wrote: we can
 421  * merely adjust ptr->offset to point to the start of the data that is currently
 422  * live. The size field in struct bkey records the current (live) size of the
 423  * extent, and is also used to mean "size of region on disk that we point to" in
 424  * this case.
 425  *
 426  * Thus an extent that is not checksummed or compressed will consist only of a
 427  * list of bch_extent_ptrs, with none of the fields in
 428  * bch_extent_crc32/bch_extent_crc64.
 429  *
 430  * When an extent is checksummed or compressed, it's not possible to read only
 431  * the data that is currently live: we have to read the entire extent that was
 432  * originally written, and then return only the part of the extent that is
 433  * currently live.
 434  *
 435  * Thus, in addition to the current size of the extent in struct bkey, we need
 436  * to store the size of the originally allocated space - this is the
 437  * compressed_size and uncompressed_size fields in bch_extent_crc32/64. Also,
 438  * when the extent is trimmed, instead of modifying the offset field of the
 439  * pointer, we keep a second smaller offset field - "offset into the original
 440  * extent of the currently live region".
 441  *
 442  * The other major determining factor is replication and data migration:
 443  *
 444  * Each pointer may have its own bch_extent_crc32/64. When doing a replicated
 445  * write, we will initially write all the replicas in the same format, with the
 446  * same checksum type and compression format - however, when copygc runs later (or
 447  * tiering/cache promotion, anything that moves data), it is not in general
 448  * going to rewrite all the pointers at once - one of the replicas may be in a
 449  * bucket on one device that has very little fragmentation while another lives
 450  * in a bucket that has become heavily fragmented, and thus is being rewritten
 451  * sooner than the rest.
 452  *
 453  * Thus it will only move a subset of the pointers (or in the case of
 454  * tiering/cache promotion perhaps add a single pointer without dropping any
 455  * current pointers), and if the extent has been partially overwritten it must
 456  * write only the currently live portion (or copygc would not be able to reduce
 457  * fragmentation!) - which necessitates a different bch_extent_crc format for
 458  * the new pointer.
 459  *
 460  * But in the interests of space efficiency, we don't want to store one
 461  * bch_extent_crc for each pointer if we don't have to.
 462  *
 463  * Thus, a bch_extent consists of bch_extent_crc32s, bch_extent_crc64s, and
 464  * bch_extent_ptrs appended arbitrarily one after the other. We determine the
 465  * type of a given entry with a scheme similar to utf8 (except we're encoding a
 466  * type, not a size), encoding the type in the position of the first set bit:
 467  *
 468  * bch_extent_crc32     - 0b1
 469  * bch_extent_ptr       - 0b10
 470  * bch_extent_crc64     - 0b100
 471  *
 472  * We do it this way because bch_extent_crc32 is _very_ constrained on bits (and
 473  * bch_extent_crc64 is the least constrained).
 474  *
 475  * Then, each bch_extent_crc32/64 applies to the pointers that follow after it,
 476  * until the next bch_extent_crc32/64.
 477  *
 478  * If there are no bch_extent_crcs preceding a bch_extent_ptr, then that pointer
 479  * is neither checksummed nor compressed.
 480  */
 481
 482 /* 128 bits, sufficient for cryptographic MACs: */
 483 struct bch_csum {
 484         __le64                  lo;
 485         __le64                  hi;
 486 } __packed __aligned(8);
 487
 488 #define BCH_EXTENT_ENTRY_TYPES()                \
 489         x(ptr,                  0)              \
 490         x(crc32,                1)              \
 491         x(crc64,                2)              \
 492         x(crc128,               3)              \
 493         x(stripe_ptr,           4)              \
 494         x(rebalance,            5)
 495 #define BCH_EXTENT_ENTRY_MAX    6
 496
 497 enum bch_extent_entry_type {
 498 #define x(f, n) BCH_EXTENT_ENTRY_##f = n,
 499         BCH_EXTENT_ENTRY_TYPES()
 500 #undef x
 501 };
 502
 503 /* Compressed/uncompressed size are stored biased by 1: */
 504 struct bch_extent_crc32 {
 505 #if defined(__LITTLE_ENDIAN_BITFIELD)
 506         __u32                   type:2,
 507                                 _compressed_size:7,
 508                                 _uncompressed_size:7,
 509                                 offset:7,
 510                                 _unused:1,
 511                                 csum_type:4,
 512                                 compression_type:4;
 513         __u32                   csum;
 514 #elif defined (__BIG_ENDIAN_BITFIELD)
 515         __u32                   csum;
 516         __u32                   compression_type:4,
 517                                 csum_type:4,
 518                                 _unused:1,
 519                                 offset:7,
 520                                 _uncompressed_size:7,
 521                                 _compressed_size:7,
 522                                 type:2;
 523 #endif
 524 } __packed __aligned(8);
 525
 526 #define CRC32_SIZE_MAX          (1U << 7)
 527 #define CRC32_NONCE_MAX         0
 528
 529 struct bch_extent_crc64 {
 530 #if defined(__LITTLE_ENDIAN_BITFIELD)
 531         __u64                   type:3,
 532                                 _compressed_size:9,
 533                                 _uncompressed_size:9,
 534                                 offset:9,
 535                                 nonce:10,
 536                                 csum_type:4,
 537                                 compression_type:4,
 538                                 csum_hi:16;
 539 #elif defined (__BIG_ENDIAN_BITFIELD)
 540         __u64                   csum_hi:16,
 541                                 compression_type:4,
 542                                 csum_type:4,
 543                                 nonce:10,
 544                                 offset:9,
 545                                 _uncompressed_size:9,
 546                                 _compressed_size:9,
 547                                 type:3;
 548 #endif
 549         __u64                   csum_lo;
 550 } __packed __aligned(8);
 551
 552 #define CRC64_SIZE_MAX          (1U << 9)
 553 #define CRC64_NONCE_MAX         ((1U << 10) - 1)
 554
 555 struct bch_extent_crc128 {
 556 #if defined(__LITTLE_ENDIAN_BITFIELD)
 557         __u64                   type:4,
 558                                 _compressed_size:13,
 559                                 _uncompressed_size:13,
 560                                 offset:13,
 561                                 nonce:13,
 562                                 csum_type:4,
 563                                 compression_type:4;
 564 #elif defined (__BIG_ENDIAN_BITFIELD)
 565         __u64                   compression_type:4,
 566                                 csum_type:4,
 567                                 nonce:13,
 568                                 offset:13,
 569                                 _uncompressed_size:13,
 570                                 _compressed_size:13,
 571                                 type:4;
 572 #endif
 573         struct bch_csum         csum;
 574 } __packed __aligned(8);
 575
 576 #define CRC128_SIZE_MAX         (1U << 13)
 577 #define CRC128_NONCE_MAX        ((1U << 13) - 1)
 578
 579 /*
 580  * @reservation - pointer hasn't been written to, just reserved
 581  */
 582 struct bch_extent_ptr {
 583 #if defined(__LITTLE_ENDIAN_BITFIELD)
 584         __u64                   type:1,
 585                                 cached:1,
 586                                 unused:1,
 587                                 unwritten:1,
 588                                 offset:44, /* 8 petabytes */
 589                                 dev:8,
 590                                 gen:8;
 591 #elif defined (__BIG_ENDIAN_BITFIELD)
 592         __u64                   gen:8,
 593                                 dev:8,
 594                                 offset:44,
 595                                 unwritten:1,
 596                                 unused:1,
 597                                 cached:1,
 598                                 type:1;
 599 #endif
 600 } __packed __aligned(8);
 601
 602 struct bch_extent_stripe_ptr {
 603 #if defined(__LITTLE_ENDIAN_BITFIELD)
 604         __u64                   type:5,
 605                                 block:8,
 606                                 redundancy:4,
 607                                 idx:47;
 608 #elif defined (__BIG_ENDIAN_BITFIELD)
 609         __u64                   idx:47,
 610                                 redundancy:4,
 611                                 block:8,
 612                                 type:5;
 613 #endif
 614 };
 615
 616 struct bch_extent_rebalance {
 617 #if defined(__LITTLE_ENDIAN_BITFIELD)
 618         __u64                   type:6,
 619                                 unused:34,
 620                                 compression:8, /* enum bch_compression_opt */
 621                                 target:16;
 622 #elif defined (__BIG_ENDIAN_BITFIELD)
 623         __u64                   target:16,
 624                                 compression:8,
 625                                 unused:34,
 626                                 type:6;
 627 #endif
 628 };
 629
 630 union bch_extent_entry {
 631 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ||  __BITS_PER_LONG == 64
 632         unsigned long                   type;
 633 #elif __BITS_PER_LONG == 32
 634         struct {
 635                 unsigned long           pad;
 636                 unsigned long           type;
 637         };
 638 #else
 639 #error edit for your odd byteorder.
 640 #endif
 641
 642 #define x(f, n) struct bch_extent_##f   f;
 643         BCH_EXTENT_ENTRY_TYPES()
 644 #undef x
 645 };
 646
 647 struct bch_btree_ptr {
 648         struct bch_val          v;
 649
 650         __u64                   _data[0];
 651         struct bch_extent_ptr   start[];
 652 } __packed __aligned(8);
 653
 654 struct bch_btree_ptr_v2 {
 655         struct bch_val          v;
 656
 657         __u64                   mem_ptr;
 658         __le64                  seq;
 659         __le16                  sectors_written;
 660         __le16                  flags;
 661         struct bpos             min_key;
 662         __u64                   _data[0];
 663         struct bch_extent_ptr   start[];
 664 } __packed __aligned(8);
 665
 666 LE16_BITMASK(BTREE_PTR_RANGE_UPDATED,   struct bch_btree_ptr_v2, flags, 0, 1);
 667
 668 struct bch_extent {
 669         struct bch_val          v;
 670
 671         __u64                   _data[0];
 672         union bch_extent_entry  start[];
 673 } __packed __aligned(8);
 674
 675 struct bch_reservation {
 676         struct bch_val          v;
 677
 678         __le32                  generation;
 679         __u8                    nr_replicas;
 680         __u8                    pad[3];
 681 } __packed __aligned(8);
 682
 683 /* Maximum size (in u64s) a single pointer could be: */
 684 #define BKEY_EXTENT_PTR_U64s_MAX\
 685         ((sizeof(struct bch_extent_crc128) +                    \
 686           sizeof(struct bch_extent_ptr)) / sizeof(__u64))
 687
 688 /* Maximum possible size of an entire extent value: */
 689 #define BKEY_EXTENT_VAL_U64s_MAX                                \
 690         (1 + BKEY_EXTENT_PTR_U64s_MAX * (BCH_REPLICAS_MAX + 1))
 691
 692 /* * Maximum possible size of an entire extent, key + value: */
 693 #define BKEY_EXTENT_U64s_MAX            (BKEY_U64s + BKEY_EXTENT_VAL_U64s_MAX)
 694
 695 /* Btree pointers don't carry around checksums: */
 696 #define BKEY_BTREE_PTR_VAL_U64s_MAX                             \
 697         ((sizeof(struct bch_btree_ptr_v2) +                     \
 698           sizeof(struct bch_extent_ptr) * BCH_REPLICAS_MAX) / sizeof(__u64))
 699 #define BKEY_BTREE_PTR_U64s_MAX                                 \
 700         (BKEY_U64s + BKEY_BTREE_PTR_VAL_U64s_MAX)
 701
 702 /* Inodes */
 703
 704 #define BLOCKDEV_INODE_MAX      4096
 705
 706 #define BCACHEFS_ROOT_INO       4096
 707
 708 struct bch_inode {
 709         struct bch_val          v;
 710
 711         __le64                  bi_hash_seed;
 712         __le32                  bi_flags;
 713         __le16                  bi_mode;
 714         __u8                    fields[];
 715 } __packed __aligned(8);
 716
 717 struct bch_inode_v2 {
 718         struct bch_val          v;
 719
 720         __le64                  bi_journal_seq;
 721         __le64                  bi_hash_seed;
 722         __le64                  bi_flags;
 723         __le16                  bi_mode;
 724         __u8                    fields[];
 725 } __packed __aligned(8);
 726
 727 struct bch_inode_v3 {
 728         struct bch_val          v;
 729
 730         __le64                  bi_journal_seq;
 731         __le64                  bi_hash_seed;
 732         __le64                  bi_flags;
 733         __le64                  bi_sectors;
 734         __le64                  bi_size;
 735         __le64                  bi_version;
 736         __u8                    fields[];
 737 } __packed __aligned(8);
 738
 739 #define INODEv3_FIELDS_START_INITIAL    6
 740 #define INODEv3_FIELDS_START_CUR        (offsetof(struct bch_inode_v3, fields) / sizeof(__u64))
 741
 742 struct bch_inode_generation {
 743         struct bch_val          v;
 744
 745         __le32                  bi_generation;
 746         __le32                  pad;
 747 } __packed __aligned(8);
 748
 749 /*
 750  * bi_subvol and bi_parent_subvol are only set for subvolume roots:
 751  */
 752
 753 #define BCH_INODE_FIELDS_v2()                   \
 754         x(bi_atime,                     96)     \
 755         x(bi_ctime,                     96)     \
 756         x(bi_mtime,                     96)     \
 757         x(bi_otime,                     96)     \
 758         x(bi_size,                      64)     \
 759         x(bi_sectors,                   64)     \
 760         x(bi_uid,                       32)     \
 761         x(bi_gid,                       32)     \
 762         x(bi_nlink,                     32)     \
 763         x(bi_generation,                32)     \
 764         x(bi_dev,                       32)     \
 765         x(bi_data_checksum,             8)      \
 766         x(bi_compression,               8)      \
 767         x(bi_project,                   32)     \
 768         x(bi_background_compression,    8)      \
 769         x(bi_data_replicas,             8)      \
 770         x(bi_promote_target,            16)     \
 771         x(bi_foreground_target,         16)     \
 772         x(bi_background_target,         16)     \
 773         x(bi_erasure_code,              16)     \
 774         x(bi_fields_set,                16)     \
 775         x(bi_dir,                       64)     \
 776         x(bi_dir_offset,                64)     \
 777         x(bi_subvol,                    32)     \
 778         x(bi_parent_subvol,             32)
 779
 780 #define BCH_INODE_FIELDS_v3()                   \
 781         x(bi_atime,                     96)     \
 782         x(bi_ctime,                     96)     \
 783         x(bi_mtime,                     96)     \
 784         x(bi_otime,                     96)     \
 785         x(bi_uid,                       32)     \
 786         x(bi_gid,                       32)     \
 787         x(bi_nlink,                     32)     \
 788         x(bi_generation,                32)     \
 789         x(bi_dev,                       32)     \
 790         x(bi_data_checksum,             8)      \
 791         x(bi_compression,               8)      \
 792         x(bi_project,                   32)     \
 793         x(bi_background_compression,    8)      \
 794         x(bi_data_replicas,             8)      \
 795         x(bi_promote_target,            16)     \
 796         x(bi_foreground_target,         16)     \
 797         x(bi_background_target,         16)     \
 798         x(bi_erasure_code,              16)     \
 799         x(bi_fields_set,                16)     \
 800         x(bi_dir,                       64)     \
 801         x(bi_dir_offset,                64)     \
 802         x(bi_subvol,                    32)     \
 803         x(bi_parent_subvol,             32)     \
 804         x(bi_nocow,                     8)
 805
 806 /* subset of BCH_INODE_FIELDS */
 807 #define BCH_INODE_OPTS()                        \
 808         x(data_checksum,                8)      \
 809         x(compression,                  8)      \
 810         x(project,                      32)     \
 811         x(background_compression,       8)      \
 812         x(data_replicas,                8)      \
 813         x(promote_target,               16)     \
 814         x(foreground_target,            16)     \
 815         x(background_target,            16)     \
 816         x(erasure_code,                 16)     \
 817         x(nocow,                        8)
 818
 819 enum inode_opt_id {
 820 #define x(name, ...)                            \
 821         Inode_opt_##name,
 822         BCH_INODE_OPTS()
 823 #undef  x
 824         Inode_opt_nr,
 825 };
 826
 827 enum {
 828         /*
 829          * User flags (get/settable with FS_IOC_*FLAGS, correspond to FS_*_FL
 830          * flags)
 831          */
 832         __BCH_INODE_SYNC                = 0,
 833         __BCH_INODE_IMMUTABLE           = 1,
 834         __BCH_INODE_APPEND              = 2,
 835         __BCH_INODE_NODUMP              = 3,
 836         __BCH_INODE_NOATIME             = 4,
 837
 838         __BCH_INODE_I_SIZE_DIRTY        = 5, /* obsolete */
 839         __BCH_INODE_I_SECTORS_DIRTY     = 6, /* obsolete */
 840         __BCH_INODE_UNLINKED            = 7,
 841         __BCH_INODE_BACKPTR_UNTRUSTED   = 8,
 842
 843         /* bits 20+ reserved for packed fields below: */
 844 };
 845
 846 #define BCH_INODE_SYNC          (1 << __BCH_INODE_SYNC)
 847 #define BCH_INODE_IMMUTABLE     (1 << __BCH_INODE_IMMUTABLE)
 848 #define BCH_INODE_APPEND        (1 << __BCH_INODE_APPEND)
 849 #define BCH_INODE_NODUMP        (1 << __BCH_INODE_NODUMP)
 850 #define BCH_INODE_NOATIME       (1 << __BCH_INODE_NOATIME)
 851 #define BCH_INODE_I_SIZE_DIRTY  (1 << __BCH_INODE_I_SIZE_DIRTY)
 852 #define BCH_INODE_I_SECTORS_DIRTY (1 << __BCH_INODE_I_SECTORS_DIRTY)
 853 #define BCH_INODE_UNLINKED      (1 << __BCH_INODE_UNLINKED)
 854 #define BCH_INODE_BACKPTR_UNTRUSTED (1 << __BCH_INODE_BACKPTR_UNTRUSTED)
 855
 856 LE32_BITMASK(INODE_STR_HASH,    struct bch_inode, bi_flags, 20, 24);
 857 LE32_BITMASK(INODE_NR_FIELDS,   struct bch_inode, bi_flags, 24, 31);
 858 LE32_BITMASK(INODE_NEW_VARINT,  struct bch_inode, bi_flags, 31, 32);
 859
 860 LE64_BITMASK(INODEv2_STR_HASH,  struct bch_inode_v2, bi_flags, 20, 24);
 861 LE64_BITMASK(INODEv2_NR_FIELDS, struct bch_inode_v2, bi_flags, 24, 31);
 862
 863 LE64_BITMASK(INODEv3_STR_HASH,  struct bch_inode_v3, bi_flags, 20, 24);
 864 LE64_BITMASK(INODEv3_NR_FIELDS, struct bch_inode_v3, bi_flags, 24, 31);
 865
 866 LE64_BITMASK(INODEv3_FIELDS_START,
 867                                 struct bch_inode_v3, bi_flags, 31, 36);
 868 LE64_BITMASK(INODEv3_MODE,      struct bch_inode_v3, bi_flags, 36, 52);
 869
 870 /* Dirents */
 871
 872 /*
 873  * Dirents (and xattrs) have to implement string lookups; since our b-tree
 874  * doesn't support arbitrary length strings for the key, we instead index by a
 875  * 64 bit hash (currently truncated sha1) of the string, stored in the offset
 876  * field of the key - using linear probing to resolve hash collisions. This also
 877  * provides us with the readdir cookie posix requires.
 878  *
 879  * Linear probing requires us to use whiteouts for deletions, in the event of a
 880  * collision:
 881  */
 882
 883 struct bch_dirent {
 884         struct bch_val          v;
 885
 886         /* Target inode number: */
 887         union {
 888         __le64                  d_inum;
 889         struct {                /* DT_SUBVOL */
 890         __le32                  d_child_subvol;
 891         __le32                  d_parent_subvol;
 892         };
 893         };
 894
 895         /*
 896          * Copy of mode bits 12-15 from the target inode - so userspace can get
 897          * the filetype without having to do a stat()
 898          */
 899         __u8                    d_type;
 900
 901         __u8                    d_name[];
 902 } __packed __aligned(8);
 903
 904 #define DT_SUBVOL       16
 905 #define BCH_DT_MAX      17
 906
 907 #define BCH_NAME_MAX    512
 908
 909 /* Xattrs */
 910
 911 #define KEY_TYPE_XATTR_INDEX_USER                       0
 912 #define KEY_TYPE_XATTR_INDEX_POSIX_ACL_ACCESS   1
 913 #define KEY_TYPE_XATTR_INDEX_POSIX_ACL_DEFAULT  2
 914 #define KEY_TYPE_XATTR_INDEX_TRUSTED                    3
 915 #define KEY_TYPE_XATTR_INDEX_SECURITY           4
 916
 917 struct bch_xattr {
 918         struct bch_val          v;
 919         __u8                    x_type;
 920         __u8                    x_name_len;
 921         __le16                  x_val_len;
 922         __u8                    x_name[];
 923 } __packed __aligned(8);
 924
 925 /* Bucket/allocation information: */
 926
 927 struct bch_alloc {
 928         struct bch_val          v;
 929         __u8                    fields;
 930         __u8                    gen;
 931         __u8                    data[];
 932 } __packed __aligned(8);
 933
 934 #define BCH_ALLOC_FIELDS_V1()                   \
 935         x(read_time,            16)             \
 936         x(write_time,           16)             \
 937         x(data_type,            8)              \
 938         x(dirty_sectors,        16)             \
 939         x(cached_sectors,       16)             \
 940         x(oldest_gen,           8)              \
 941         x(stripe,               32)             \
 942         x(stripe_redundancy,    8)
 943
 944 enum {
 945 #define x(name, _bits) BCH_ALLOC_FIELD_V1_##name,
 946         BCH_ALLOC_FIELDS_V1()
 947 #undef x
 948 };
 949
 950 struct bch_alloc_v2 {
 951         struct bch_val          v;
 952         __u8                    nr_fields;
 953         __u8                    gen;
 954         __u8                    oldest_gen;
 955         __u8                    data_type;
 956         __u8                    data[];
 957 } __packed __aligned(8);
 958
 959 #define BCH_ALLOC_FIELDS_V2()                   \
 960         x(read_time,            64)             \
 961         x(write_time,           64)             \
 962         x(dirty_sectors,        32)             \
 963         x(cached_sectors,       32)             \
 964         x(stripe,               32)             \
 965         x(stripe_redundancy,    8)
 966
 967 struct bch_alloc_v3 {
 968         struct bch_val          v;
 969         __le64                  journal_seq;
 970         __le32                  flags;
 971         __u8                    nr_fields;
 972         __u8                    gen;
 973         __u8                    oldest_gen;
 974         __u8                    data_type;
 975         __u8                    data[];
 976 } __packed __aligned(8);
 977
 978 LE32_BITMASK(BCH_ALLOC_V3_NEED_DISCARD,struct bch_alloc_v3, flags,  0,  1)
 979 LE32_BITMASK(BCH_ALLOC_V3_NEED_INC_GEN,struct bch_alloc_v3, flags,  1,  2)
 980
 981 struct bch_alloc_v4 {
 982         struct bch_val          v;
 983         __u64                   journal_seq;
 984         __u32                   flags;
 985         __u8                    gen;
 986         __u8                    oldest_gen;
 987         __u8                    data_type;
 988         __u8                    stripe_redundancy;
 989         __u32                   dirty_sectors;
 990         __u32                   cached_sectors;
 991         __u64                   io_time[2];
 992         __u32                   stripe;
 993         __u32                   nr_external_backpointers;
 994         __u64                   fragmentation_lru;
 995 } __packed __aligned(8);
 996
 997 #define BCH_ALLOC_V4_U64s_V0    6
 998 #define BCH_ALLOC_V4_U64s       (sizeof(struct bch_alloc_v4) / sizeof(__u64))
 999
1000 BITMASK(BCH_ALLOC_V4_NEED_DISCARD,      struct bch_alloc_v4, flags,  0,  1)
1001 BITMASK(BCH_ALLOC_V4_NEED_INC_GEN,      struct bch_alloc_v4, flags,  1,  2)
1002 BITMASK(BCH_ALLOC_V4_BACKPOINTERS_START,struct bch_alloc_v4, flags,  2,  8)
1003 BITMASK(BCH_ALLOC_V4_NR_BACKPOINTERS,   struct bch_alloc_v4, flags,  8,  14)
1004
1005 #define BCH_ALLOC_V4_NR_BACKPOINTERS_MAX        40
1006
1007 struct bch_backpointer {
1008         struct bch_val          v;
1009         __u8                    btree_id;
1010         __u8                    level;
1011         __u8                    data_type;
1012         __u64                   bucket_offset:40;
1013         __u32                   bucket_len;
1014         struct bpos             pos;
1015 } __packed __aligned(8);
1016
1017 #define KEY_TYPE_BUCKET_GENS_BITS       8
1018 #define KEY_TYPE_BUCKET_GENS_NR         (1U << KEY_TYPE_BUCKET_GENS_BITS)
1019 #define KEY_TYPE_BUCKET_GENS_MASK       (KEY_TYPE_BUCKET_GENS_NR - 1)
1020
1021 struct bch_bucket_gens {
1022         struct bch_val          v;
1023         u8                      gens[KEY_TYPE_BUCKET_GENS_NR];
1024 } __packed __aligned(8);
1025
1026 /* Quotas: */
1027
1028 enum quota_types {
1029         QTYP_USR                = 0,
1030         QTYP_GRP                = 1,
1031         QTYP_PRJ                = 2,
1032         QTYP_NR                 = 3,
1033 };
1034
1035 enum quota_counters {
1036         Q_SPC                   = 0,
1037         Q_INO                   = 1,
1038         Q_COUNTERS              = 2,
1039 };
1040
1041 struct bch_quota_counter {
1042         __le64                  hardlimit;
1043         __le64                  softlimit;
1044 };
1045
1046 struct bch_quota {
1047         struct bch_val          v;
1048         struct bch_quota_counter c[Q_COUNTERS];
1049 } __packed __aligned(8);
1050
1051 /* Erasure coding */
1052
1053 struct bch_stripe {
1054         struct bch_val          v;
1055         __le16                  sectors;
1056         __u8                    algorithm;
1057         __u8                    nr_blocks;
1058         __u8                    nr_redundant;
1059
1060         __u8                    csum_granularity_bits;
1061         __u8                    csum_type;
1062         __u8                    pad;
1063
1064         struct bch_extent_ptr   ptrs[];
1065 } __packed __aligned(8);
1066
1067 /* Reflink: */
1068
1069 struct bch_reflink_p {
1070         struct bch_val          v;
1071         __le64                  idx;
1072         /*
1073          * A reflink pointer might point to an indirect extent which is then
1074          * later split (by copygc or rebalance). If we only pointed to part of
1075          * the original indirect extent, and then one of the fragments is
1076          * outside the range we point to, we'd leak a refcount: so when creating
1077          * reflink pointers, we need to store pad values to remember the full
1078          * range we were taking a reference on.
1079          */
1080         __le32                  front_pad;
1081         __le32                  back_pad;
1082 } __packed __aligned(8);
1083
1084 struct bch_reflink_v {
1085         struct bch_val          v;
1086         __le64                  refcount;
1087         union bch_extent_entry  start[0];
1088         __u64                   _data[];
1089 } __packed __aligned(8);
1090
1091 struct bch_indirect_inline_data {
1092         struct bch_val          v;
1093         __le64                  refcount;
1094         u8                      data[];
1095 };
1096
1097 /* Inline data */
1098
1099 struct bch_inline_data {
1100         struct bch_val          v;
1101         u8                      data[];
1102 };
1103
1104 /* Subvolumes: */
1105
1106 #define SUBVOL_POS_MIN          POS(0, 1)
1107 #define SUBVOL_POS_MAX          POS(0, S32_MAX)
1108 #define BCACHEFS_ROOT_SUBVOL    1
1109
1110 struct bch_subvolume {
1111         struct bch_val          v;
1112         __le32                  flags;
1113         __le32                  snapshot;
1114         __le64                  inode;
1115         /*
1116          * Snapshot subvolumes form a tree, separate from the snapshot nodes
1117          * tree - if this subvolume is a snapshot, this is the ID of the
1118          * subvolume it was created from:
1119          */
1120         __le32                  parent;
1121         __le32                  pad;
1122         bch_le128               otime;
1123 };
1124
1125 LE32_BITMASK(BCH_SUBVOLUME_RO,          struct bch_subvolume, flags,  0,  1)
1126 /*
1127  * We need to know whether a subvolume is a snapshot so we can know whether we
1128  * can delete it (or whether it should just be rm -rf'd)
1129  */
1130 LE32_BITMASK(BCH_SUBVOLUME_SNAP,        struct bch_subvolume, flags,  1,  2)
1131 LE32_BITMASK(BCH_SUBVOLUME_UNLINKED,    struct bch_subvolume, flags,  2,  3)
1132
1133 /* Snapshots */
1134
1135 struct bch_snapshot {
1136         struct bch_val          v;
1137         __le32                  flags;
1138         __le32                  parent;
1139         __le32                  children[2];
1140         __le32                  subvol;
1141         /* corresponds to a bch_snapshot_tree in BTREE_ID_snapshot_trees */
1142         __le32                  tree;
1143         __le32                  depth;
1144         __le32                  skip[3];
1145 };
1146
1147 LE32_BITMASK(BCH_SNAPSHOT_DELETED,      struct bch_snapshot, flags,  0,  1)
1148
1149 /* True if a subvolume points to this snapshot node: */
1150 LE32_BITMASK(BCH_SNAPSHOT_SUBVOL,       struct bch_snapshot, flags,  1,  2)
1151
1152 /*
1153  * Snapshot trees:
1154  *
1155  * The snapshot_trees btree gives us persistent indentifier for each tree of
1156  * bch_snapshot nodes, and allow us to record and easily find the root/master
1157  * subvolume that other snapshots were created from:
1158  */
1159 struct bch_snapshot_tree {
1160         struct bch_val          v;
1161         __le32                  master_subvol;
1162         __le32                  root_snapshot;
1163 };
1164
1165 /* LRU btree: */
1166
1167 struct bch_lru {
1168         struct bch_val          v;
1169         __le64                  idx;
1170 } __packed __aligned(8);
1171
1172 #define LRU_ID_STRIPES          (1U << 16)
1173
1174 /* Logged operations btree: */
1175
1176 struct bch_logged_op_truncate {
1177         struct bch_val          v;
1178         __le32                  subvol;
1179         __le32                  pad;
1180         __le64                  inum;
1181         __le64                  new_i_size;
1182 };
1183
1184 enum logged_op_finsert_state {
1185         LOGGED_OP_FINSERT_start,
1186         LOGGED_OP_FINSERT_shift_extents,
1187         LOGGED_OP_FINSERT_finish,
1188 };
1189
1190 struct bch_logged_op_finsert {
1191         struct bch_val          v;
1192         __u8                    state;
1193         __u8                    pad[3];
1194         __le32                  subvol;
1195         __le64                  inum;
1196         __le64                  dst_offset;
1197         __le64                  src_offset;
1198         __le64                  pos;
1199 };
1200
1201 /* Optional/variable size superblock sections: */
1202
1203 struct bch_sb_field {
1204         __u64                   _data[0];
1205         __le32                  u64s;
1206         __le32                  type;
1207 };
1208
1209 #define BCH_SB_FIELDS()                         \
1210         x(journal,      0)                      \
1211         x(members_v1,   1)                      \
1212         x(crypt,        2)                      \
1213         x(replicas_v0,  3)                      \
1214         x(quota,        4)                      \
1215         x(disk_groups,  5)                      \
1216         x(clean,        6)                      \
1217         x(replicas,     7)                      \
1218         x(journal_seq_blacklist, 8)             \
1219         x(journal_v2,   9)                      \
1220         x(counters,     10)                     \
1221         x(members_v2,   11)
1222
1223 enum bch_sb_field_type {
1224 #define x(f, nr)        BCH_SB_FIELD_##f = nr,
1225         BCH_SB_FIELDS()
1226 #undef x
1227         BCH_SB_FIELD_NR
1228 };
1229
1230 /*
1231  * Most superblock fields are replicated in all device's superblocks - a few are
1232  * not:
1233  */
1234 #define BCH_SINGLE_DEVICE_SB_FIELDS             \
1235         ((1U << BCH_SB_FIELD_journal)|          \
1236          (1U << BCH_SB_FIELD_journal_v2))
1237
1238 /* BCH_SB_FIELD_journal: */
1239
1240 struct bch_sb_field_journal {
1241         struct bch_sb_field     field;
1242         __le64                  buckets[];
1243 };
1244
1245 struct bch_sb_field_journal_v2 {
1246         struct bch_sb_field     field;
1247
1248         struct bch_sb_field_journal_v2_entry {
1249                 __le64          start;
1250                 __le64          nr;
1251         }                       d[];
1252 };
1253
1254 /* BCH_SB_FIELD_members_v1: */
1255
1256 #define BCH_MIN_NR_NBUCKETS     (1 << 6)
1257
1258 #define BCH_IOPS_MEASUREMENTS()                 \
1259         x(seqread,      0)                      \
1260         x(seqwrite,     1)                      \
1261         x(randread,     2)                      \
1262         x(randwrite,    3)
1263
1264 enum bch_iops_measurement {
1265 #define x(t, n) BCH_IOPS_##t = n,
1266         BCH_IOPS_MEASUREMENTS()
1267 #undef x
1268         BCH_IOPS_NR
1269 };
1270
1271 struct bch_member {
1272         __uuid_t                uuid;
1273         __le64                  nbuckets;       /* device size */
1274         __le16                  first_bucket;   /* index of first bucket used */
1275         __le16                  bucket_size;    /* sectors */
1276         __le32                  pad;
1277         __le64                  last_mount;     /* time_t */
1278
1279         __le64                  flags;
1280         __le32                  iops[4];
1281 };
1282
1283 #define BCH_MEMBER_V1_BYTES     56
1284
1285 LE64_BITMASK(BCH_MEMBER_STATE,          struct bch_member, flags,  0,  4)
1286 /* 4-14 unused, was TIER, HAS_(META)DATA, REPLACEMENT */
1287 LE64_BITMASK(BCH_MEMBER_DISCARD,        struct bch_member, flags, 14, 15)
1288 LE64_BITMASK(BCH_MEMBER_DATA_ALLOWED,   struct bch_member, flags, 15, 20)
1289 LE64_BITMASK(BCH_MEMBER_GROUP,          struct bch_member, flags, 20, 28)
1290 LE64_BITMASK(BCH_MEMBER_DURABILITY,     struct bch_member, flags, 28, 30)
1291 LE64_BITMASK(BCH_MEMBER_FREESPACE_INITIALIZED,
1292                                         struct bch_member, flags, 30, 31)
1293
1294 #if 0
1295 LE64_BITMASK(BCH_MEMBER_NR_READ_ERRORS, struct bch_member, flags[1], 0,  20);
1296 LE64_BITMASK(BCH_MEMBER_NR_WRITE_ERRORS,struct bch_member, flags[1], 20, 40);
1297 #endif
1298
1299 #define BCH_MEMBER_STATES()                     \
1300         x(rw,           0)                      \
1301         x(ro,           1)                      \
1302         x(failed,       2)                      \
1303         x(spare,        3)
1304
1305 enum bch_member_state {
1306 #define x(t, n) BCH_MEMBER_STATE_##t = n,
1307         BCH_MEMBER_STATES()
1308 #undef x
1309         BCH_MEMBER_STATE_NR
1310 };
1311
1312 struct bch_sb_field_members_v1 {
1313         struct bch_sb_field     field;
1314         struct bch_member       _members[]; //Members are now variable size
1315 };
1316
1317 struct bch_sb_field_members_v2 {
1318         struct bch_sb_field     field;
1319         __le16                  member_bytes; //size of single member entry
1320         u8                      pad[6];
1321         struct bch_member       _members[];
1322 };
1323
1324 /* BCH_SB_FIELD_crypt: */
1325
1326 struct nonce {
1327         __le32                  d[4];
1328 };
1329
1330 struct bch_key {
1331         __le64                  key[4];
1332 };
1333
1334 #define BCH_KEY_MAGIC                                   \
1335         (((__u64) 'b' <<  0)|((__u64) 'c' <<  8)|               \
1336          ((__u64) 'h' << 16)|((__u64) '*' << 24)|               \
1337          ((__u64) '*' << 32)|((__u64) 'k' << 40)|               \
1338          ((__u64) 'e' << 48)|((__u64) 'y' << 56))
1339
1340 struct bch_encrypted_key {
1341         __le64                  magic;
1342         struct bch_key          key;
1343 };
1344
1345 /*
1346  * If this field is present in the superblock, it stores an encryption key which
1347  * is used encrypt all other data/metadata. The key will normally be encrypted
1348  * with the key userspace provides, but if encryption has been turned off we'll
1349  * just store the master key unencrypted in the superblock so we can access the
1350  * previously encrypted data.
1351  */
1352 struct bch_sb_field_crypt {
1353         struct bch_sb_field     field;
1354
1355         __le64                  flags;
1356         __le64                  kdf_flags;
1357         struct bch_encrypted_key key;
1358 };
1359
1360 LE64_BITMASK(BCH_CRYPT_KDF_TYPE,        struct bch_sb_field_crypt, flags, 0, 4);
1361
1362 enum bch_kdf_types {
1363         BCH_KDF_SCRYPT          = 0,
1364         BCH_KDF_NR              = 1,
1365 };
1366
1367 /* stored as base 2 log of scrypt params: */
1368 LE64_BITMASK(BCH_KDF_SCRYPT_N,  struct bch_sb_field_crypt, kdf_flags,  0, 16);
1369 LE64_BITMASK(BCH_KDF_SCRYPT_R,  struct bch_sb_field_crypt, kdf_flags, 16, 32);
1370 LE64_BITMASK(BCH_KDF_SCRYPT_P,  struct bch_sb_field_crypt, kdf_flags, 32, 48);
1371
1372 /* BCH_SB_FIELD_replicas: */
1373
1374 #define BCH_DATA_TYPES()                \
1375         x(free,         0)              \
1376         x(sb,           1)              \
1377         x(journal,      2)              \
1378         x(btree,        3)              \
1379         x(user,         4)              \
1380         x(cached,       5)              \
1381         x(parity,       6)              \
1382         x(stripe,       7)              \
1383         x(need_gc_gens, 8)              \
1384         x(need_discard, 9)
1385
1386 enum bch_data_type {
1387 #define x(t, n) BCH_DATA_##t,
1388         BCH_DATA_TYPES()
1389 #undef x
1390         BCH_DATA_NR
1391 };
1392
1393 static inline bool data_type_is_empty(enum bch_data_type type)
1394 {
1395         switch (type) {
1396         case BCH_DATA_free:
1397         case BCH_DATA_need_gc_gens:
1398         case BCH_DATA_need_discard:
1399                 return true;
1400         default:
1401                 return false;
1402         }
1403 }
1404
1405 static inline bool data_type_is_hidden(enum bch_data_type type)
1406 {
1407         switch (type) {
1408         case BCH_DATA_sb:
1409         case BCH_DATA_journal:
1410                 return true;
1411         default:
1412                 return false;
1413         }
1414 }
1415
1416 struct bch_replicas_entry_v0 {
1417         __u8                    data_type;
1418         __u8                    nr_devs;
1419         __u8                    devs[];
1420 } __packed;
1421
1422 struct bch_sb_field_replicas_v0 {
1423         struct bch_sb_field     field;
1424         struct bch_replicas_entry_v0 entries[];
1425 } __packed __aligned(8);
1426
1427 struct bch_replicas_entry {
1428         __u8                    data_type;
1429         __u8                    nr_devs;
1430         __u8                    nr_required;
1431         __u8                    devs[];
1432 } __packed;
1433
1434 #define replicas_entry_bytes(_i)                                        \
1435         (offsetof(typeof(*(_i)), devs) + (_i)->nr_devs)
1436
1437 struct bch_sb_field_replicas {
1438         struct bch_sb_field     field;
1439         struct bch_replicas_entry entries[];
1440 } __packed __aligned(8);
1441
1442 /* BCH_SB_FIELD_quota: */
1443
1444 struct bch_sb_quota_counter {
1445         __le32                          timelimit;
1446         __le32                          warnlimit;
1447 };
1448
1449 struct bch_sb_quota_type {
1450         __le64                          flags;
1451         struct bch_sb_quota_counter     c[Q_COUNTERS];
1452 };
1453
1454 struct bch_sb_field_quota {
1455         struct bch_sb_field             field;
1456         struct bch_sb_quota_type        q[QTYP_NR];
1457 } __packed __aligned(8);
1458
1459 /* BCH_SB_FIELD_disk_groups: */
1460
1461 #define BCH_SB_LABEL_SIZE               32
1462
1463 struct bch_disk_group {
1464         __u8                    label[BCH_SB_LABEL_SIZE];
1465         __le64                  flags[2];
1466 } __packed __aligned(8);
1467
1468 LE64_BITMASK(BCH_GROUP_DELETED,         struct bch_disk_group, flags[0], 0,  1)
1469 LE64_BITMASK(BCH_GROUP_DATA_ALLOWED,    struct bch_disk_group, flags[0], 1,  6)
1470 LE64_BITMASK(BCH_GROUP_PARENT,          struct bch_disk_group, flags[0], 6, 24)
1471
1472 struct bch_sb_field_disk_groups {
1473         struct bch_sb_field     field;
1474         struct bch_disk_group   entries[];
1475 } __packed __aligned(8);
1476
1477 /* BCH_SB_FIELD_counters */
1478
1479 #define BCH_PERSISTENT_COUNTERS()                               \
1480         x(io_read,                                      0)      \
1481         x(io_write,                                     1)      \
1482         x(io_move,                                      2)      \
1483         x(bucket_invalidate,                            3)      \
1484         x(bucket_discard,                               4)      \
1485         x(bucket_alloc,                                 5)      \
1486         x(bucket_alloc_fail,                            6)      \
1487         x(btree_cache_scan,                             7)      \
1488         x(btree_cache_reap,                             8)      \
1489         x(btree_cache_cannibalize,                      9)      \
1490         x(btree_cache_cannibalize_lock,                 10)     \
1491         x(btree_cache_cannibalize_lock_fail,            11)     \
1492         x(btree_cache_cannibalize_unlock,               12)     \
1493         x(btree_node_write,                             13)     \
1494         x(btree_node_read,                              14)     \
1495         x(btree_node_compact,                           15)     \
1496         x(btree_node_merge,                             16)     \
1497         x(btree_node_split,                             17)     \
1498         x(btree_node_rewrite,                           18)     \
1499         x(btree_node_alloc,                             19)     \
1500         x(btree_node_free,                              20)     \
1501         x(btree_node_set_root,                          21)     \
1502         x(btree_path_relock_fail,                       22)     \
1503         x(btree_path_upgrade_fail,                      23)     \
1504         x(btree_reserve_get_fail,                       24)     \
1505         x(journal_entry_full,                           25)     \
1506         x(journal_full,                                 26)     \
1507         x(journal_reclaim_finish,                       27)     \
1508         x(journal_reclaim_start,                        28)     \
1509         x(journal_write,                                29)     \
1510         x(read_promote,                                 30)     \
1511         x(read_bounce,                                  31)     \
1512         x(read_split,                                   33)     \
1513         x(read_retry,                                   32)     \
1514         x(read_reuse_race,                              34)     \
1515         x(move_extent_read,                             35)     \
1516         x(move_extent_write,                            36)     \
1517         x(move_extent_finish,                           37)     \
1518         x(move_extent_fail,                             38)     \
1519         x(move_extent_alloc_mem_fail,                   39)     \
1520         x(copygc,                                       40)     \
1521         x(copygc_wait,                                  41)     \
1522         x(gc_gens_end,                                  42)     \
1523         x(gc_gens_start,                                43)     \
1524         x(trans_blocked_journal_reclaim,                44)     \
1525         x(trans_restart_btree_node_reused,              45)     \
1526         x(trans_restart_btree_node_split,               46)     \
1527         x(trans_restart_fault_inject,                   47)     \
1528         x(trans_restart_iter_upgrade,                   48)     \
1529         x(trans_restart_journal_preres_get,             49)     \
1530         x(trans_restart_journal_reclaim,                50)     \
1531         x(trans_restart_journal_res_get,                51)     \
1532         x(trans_restart_key_cache_key_realloced,        52)     \
1533         x(trans_restart_key_cache_raced,                53)     \
1534         x(trans_restart_mark_replicas,                  54)     \
1535         x(trans_restart_mem_realloced,                  55)     \
1536         x(trans_restart_memory_allocation_failure,      56)     \
1537         x(trans_restart_relock,                         57)     \
1538         x(trans_restart_relock_after_fill,              58)     \
1539         x(trans_restart_relock_key_cache_fill,          59)     \
1540         x(trans_restart_relock_next_node,               60)     \
1541         x(trans_restart_relock_parent_for_fill,         61)     \
1542         x(trans_restart_relock_path,                    62)     \
1543         x(trans_restart_relock_path_intent,             63)     \
1544         x(trans_restart_too_many_iters,                 64)     \
1545         x(trans_restart_traverse,                       65)     \
1546         x(trans_restart_upgrade,                        66)     \
1547         x(trans_restart_would_deadlock,                 67)     \
1548         x(trans_restart_would_deadlock_write,           68)     \
1549         x(trans_restart_injected,                       69)     \
1550         x(trans_restart_key_cache_upgrade,              70)     \
1551         x(trans_traverse_all,                           71)     \
1552         x(transaction_commit,                           72)     \
1553         x(write_super,                                  73)     \
1554         x(trans_restart_would_deadlock_recursion_limit, 74)     \
1555         x(trans_restart_write_buffer_flush,             75)     \
1556         x(trans_restart_split_race,                     76)
1557
1558 enum bch_persistent_counters {
1559 #define x(t, n, ...) BCH_COUNTER_##t,
1560         BCH_PERSISTENT_COUNTERS()
1561 #undef x
1562         BCH_COUNTER_NR
1563 };
1564
1565 struct bch_sb_field_counters {
1566         struct bch_sb_field     field;
1567         __le64                  d[];
1568 };
1569
1570 /*
1571  * On clean shutdown, store btree roots and current journal sequence number in
1572  * the superblock:
1573  */
1574 struct jset_entry {
1575         __le16                  u64s;
1576         __u8                    btree_id;
1577         __u8                    level;
1578         __u8                    type; /* designates what this jset holds */
1579         __u8                    pad[3];
1580
1581         struct bkey_i           start[0];
1582         __u64                   _data[];
1583 };
1584
1585 struct bch_sb_field_clean {
1586         struct bch_sb_field     field;
1587
1588         __le32                  flags;
1589         __le16                  _read_clock; /* no longer used */
1590         __le16                  _write_clock;
1591         __le64                  journal_seq;
1592
1593         struct jset_entry       start[0];
1594         __u64                   _data[];
1595 };
1596
1597 struct journal_seq_blacklist_entry {
1598         __le64                  start;
1599         __le64                  end;
1600 };
1601
1602 struct bch_sb_field_journal_seq_blacklist {
1603         struct bch_sb_field     field;
1604
1605         struct journal_seq_blacklist_entry start[0];
1606         __u64                   _data[];
1607 };
1608
1609 /* Superblock: */
1610
1611 /*
1612  * New versioning scheme:
1613  * One common version number for all on disk data structures - superblock, btree
1614  * nodes, journal entries
1615  */
1616 #define BCH_VERSION_MAJOR(_v)           ((__u16) ((_v) >> 10))
1617 #define BCH_VERSION_MINOR(_v)           ((__u16) ((_v) & ~(~0U << 10)))
1618 #define BCH_VERSION(_major, _minor)     (((_major) << 10)|(_minor) << 0)
1619
1620 #define RECOVERY_PASS_ALL_FSCK          (1ULL << 63)
1621
1622 #define BCH_METADATA_VERSIONS()                                         \
1623         x(bkey_renumber,                BCH_VERSION(0, 10),             \
1624           RECOVERY_PASS_ALL_FSCK)                                       \
1625         x(inode_btree_change,           BCH_VERSION(0, 11),             \
1626           RECOVERY_PASS_ALL_FSCK)                                       \
1627         x(snapshot,                     BCH_VERSION(0, 12),             \
1628           RECOVERY_PASS_ALL_FSCK)                                       \
1629         x(inode_backpointers,           BCH_VERSION(0, 13),             \
1630           RECOVERY_PASS_ALL_FSCK)                                       \
1631         x(btree_ptr_sectors_written,    BCH_VERSION(0, 14),             \
1632           RECOVERY_PASS_ALL_FSCK)                                       \
1633         x(snapshot_2,                   BCH_VERSION(0, 15),             \
1634           BIT_ULL(BCH_RECOVERY_PASS_fs_upgrade_for_subvolumes)|         \
1635           BIT_ULL(BCH_RECOVERY_PASS_initialize_subvolumes)|             \
1636           RECOVERY_PASS_ALL_FSCK)                                       \
1637         x(reflink_p_fix,                BCH_VERSION(0, 16),             \
1638           BIT_ULL(BCH_RECOVERY_PASS_fix_reflink_p))                     \
1639         x(subvol_dirent,                BCH_VERSION(0, 17),             \
1640           RECOVERY_PASS_ALL_FSCK)                                       \
1641         x(inode_v2,                     BCH_VERSION(0, 18),             \
1642           RECOVERY_PASS_ALL_FSCK)                                       \
1643         x(freespace,                    BCH_VERSION(0, 19),             \
1644           RECOVERY_PASS_ALL_FSCK)                                       \
1645         x(alloc_v4,                     BCH_VERSION(0, 20),             \
1646           RECOVERY_PASS_ALL_FSCK)                                       \
1647         x(new_data_types,               BCH_VERSION(0, 21),             \
1648           RECOVERY_PASS_ALL_FSCK)                                       \
1649         x(backpointers,                 BCH_VERSION(0, 22),             \
1650           RECOVERY_PASS_ALL_FSCK)                                       \
1651         x(inode_v3,                     BCH_VERSION(0, 23),             \
1652           RECOVERY_PASS_ALL_FSCK)                                       \
1653         x(unwritten_extents,            BCH_VERSION(0, 24),             \
1654           RECOVERY_PASS_ALL_FSCK)                                       \
1655         x(bucket_gens,                  BCH_VERSION(0, 25),             \
1656           BIT_ULL(BCH_RECOVERY_PASS_bucket_gens_init)|                  \
1657           RECOVERY_PASS_ALL_FSCK)                                       \
1658         x(lru_v2,                       BCH_VERSION(0, 26),             \
1659           RECOVERY_PASS_ALL_FSCK)                                       \
1660         x(fragmentation_lru,            BCH_VERSION(0, 27),             \
1661           RECOVERY_PASS_ALL_FSCK)                                       \
1662         x(no_bps_in_alloc_keys,         BCH_VERSION(0, 28),             \
1663           RECOVERY_PASS_ALL_FSCK)                                       \
1664         x(snapshot_trees,               BCH_VERSION(0, 29),             \
1665           RECOVERY_PASS_ALL_FSCK)                                       \
1666         x(major_minor,                  BCH_VERSION(1,  0),             \
1667           0)                                                            \
1668         x(snapshot_skiplists,           BCH_VERSION(1,  1),             \
1669           BIT_ULL(BCH_RECOVERY_PASS_check_snapshots))                   \
1670         x(deleted_inodes,               BCH_VERSION(1,  2),             \
1671           BIT_ULL(BCH_RECOVERY_PASS_check_inodes))                      \
1672         x(rebalance_work,               BCH_VERSION(1,  3),             \
1673           BIT_ULL(BCH_RECOVERY_PASS_set_fs_needs_rebalance))
1674
1675 enum bcachefs_metadata_version {
1676         bcachefs_metadata_version_min = 9,
1677 #define x(t, n, upgrade_passes) bcachefs_metadata_version_##t = n,
1678         BCH_METADATA_VERSIONS()
1679 #undef x
1680         bcachefs_metadata_version_max
1681 };
1682
1683 static const __maybe_unused
1684 unsigned bcachefs_metadata_required_upgrade_below = bcachefs_metadata_version_rebalance_work;
1685
1686 #define bcachefs_metadata_version_current       (bcachefs_metadata_version_max - 1)
1687
1688 #define BCH_SB_SECTOR                   8
1689 #define BCH_SB_MEMBERS_MAX              64 /* XXX kill */
1690
1691 struct bch_sb_layout {
1692         __uuid_t                magic;  /* bcachefs superblock UUID */
1693         __u8                    layout_type;
1694         __u8                    sb_max_size_bits; /* base 2 of 512 byte sectors */
1695         __u8                    nr_superblocks;
1696         __u8                    pad[5];
1697         __le64                  sb_offset[61];
1698 } __packed __aligned(8);
1699
1700 #define BCH_SB_LAYOUT_SECTOR    7
1701
1702 /*
1703  * @offset      - sector where this sb was written
1704  * @version     - on disk format version
1705  * @version_min - Oldest metadata version this filesystem contains; so we can
1706  *                safely drop compatibility code and refuse to mount filesystems
1707  *                we'd need it for
1708  * @magic       - identifies as a bcachefs superblock (BCHFS_MAGIC)
1709  * @seq         - incremented each time superblock is written
1710  * @uuid        - used for generating various magic numbers and identifying
1711  *                member devices, never changes
1712  * @user_uuid   - user visible UUID, may be changed
1713  * @label       - filesystem label
1714  * @seq         - identifies most recent superblock, incremented each time
1715  *                superblock is written
1716  * @features    - enabled incompatible features
1717  */
1718 struct bch_sb {
1719         struct bch_csum         csum;
1720         __le16                  version;
1721         __le16                  version_min;
1722         __le16                  pad[2];
1723         __uuid_t                magic;
1724         __uuid_t                uuid;
1725         __uuid_t                user_uuid;
1726         __u8                    label[BCH_SB_LABEL_SIZE];
1727         __le64                  offset;
1728         __le64                  seq;
1729
1730         __le16                  block_size;
1731         __u8                    dev_idx;
1732         __u8                    nr_devices;
1733         __le32                  u64s;
1734
1735         __le64                  time_base_lo;
1736         __le32                  time_base_hi;
1737         __le32                  time_precision;
1738
1739         __le64                  flags[8];
1740         __le64                  features[2];
1741         __le64                  compat[2];
1742
1743         struct bch_sb_layout    layout;
1744
1745         struct bch_sb_field     start[0];
1746         __le64                  _data[];
1747 } __packed __aligned(8);
1748
1749 /*
1750  * Flags:
1751  * BCH_SB_INITALIZED    - set on first mount
1752  * BCH_SB_CLEAN         - did we shut down cleanly? Just a hint, doesn't affect
1753  *                        behaviour of mount/recovery path:
1754  * BCH_SB_INODE_32BIT   - limit inode numbers to 32 bits
1755  * BCH_SB_128_BIT_MACS  - 128 bit macs instead of 80
1756  * BCH_SB_ENCRYPTION_TYPE - if nonzero encryption is enabled; overrides
1757  *                         DATA/META_CSUM_TYPE. Also indicates encryption
1758  *                         algorithm in use, if/when we get more than one
1759  */
1760
1761 LE16_BITMASK(BCH_SB_BLOCK_SIZE,         struct bch_sb, block_size, 0, 16);
1762
1763 LE64_BITMASK(BCH_SB_INITIALIZED,        struct bch_sb, flags[0],  0,  1);
1764 LE64_BITMASK(BCH_SB_CLEAN,              struct bch_sb, flags[0],  1,  2);
1765 LE64_BITMASK(BCH_SB_CSUM_TYPE,          struct bch_sb, flags[0],  2,  8);
1766 LE64_BITMASK(BCH_SB_ERROR_ACTION,       struct bch_sb, flags[0],  8, 12);
1767
1768 LE64_BITMASK(BCH_SB_BTREE_NODE_SIZE,    struct bch_sb, flags[0], 12, 28);
1769
1770 LE64_BITMASK(BCH_SB_GC_RESERVE,         struct bch_sb, flags[0], 28, 33);
1771 LE64_BITMASK(BCH_SB_ROOT_RESERVE,       struct bch_sb, flags[0], 33, 40);
1772
1773 LE64_BITMASK(BCH_SB_META_CSUM_TYPE,     struct bch_sb, flags[0], 40, 44);
1774 LE64_BITMASK(BCH_SB_DATA_CSUM_TYPE,     struct bch_sb, flags[0], 44, 48);
1775
1776 LE64_BITMASK(BCH_SB_META_REPLICAS_WANT, struct bch_sb, flags[0], 48, 52);
1777 LE64_BITMASK(BCH_SB_DATA_REPLICAS_WANT, struct bch_sb, flags[0], 52, 56);
1778
1779 LE64_BITMASK(BCH_SB_POSIX_ACL,          struct bch_sb, flags[0], 56, 57);
1780 LE64_BITMASK(BCH_SB_USRQUOTA,           struct bch_sb, flags[0], 57, 58);
1781 LE64_BITMASK(BCH_SB_GRPQUOTA,           struct bch_sb, flags[0], 58, 59);
1782 LE64_BITMASK(BCH_SB_PRJQUOTA,           struct bch_sb, flags[0], 59, 60);
1783
1784 LE64_BITMASK(BCH_SB_HAS_ERRORS,         struct bch_sb, flags[0], 60, 61);
1785 LE64_BITMASK(BCH_SB_HAS_TOPOLOGY_ERRORS,struct bch_sb, flags[0], 61, 62);
1786
1787 LE64_BITMASK(BCH_SB_BIG_ENDIAN,         struct bch_sb, flags[0], 62, 63);
1788
1789 LE64_BITMASK(BCH_SB_STR_HASH_TYPE,      struct bch_sb, flags[1],  0,  4);
1790 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_LO,struct bch_sb, flags[1],  4,  8);
1791 LE64_BITMASK(BCH_SB_INODE_32BIT,        struct bch_sb, flags[1],  8,  9);
1792
1793 LE64_BITMASK(BCH_SB_128_BIT_MACS,       struct bch_sb, flags[1],  9, 10);
1794 LE64_BITMASK(BCH_SB_ENCRYPTION_TYPE,    struct bch_sb, flags[1], 10, 14);
1795
1796 /*
1797  * Max size of an extent that may require bouncing to read or write
1798  * (checksummed, compressed): 64k
1799  */
1800 LE64_BITMASK(BCH_SB_ENCODED_EXTENT_MAX_BITS,
1801                                         struct bch_sb, flags[1], 14, 20);
1802
1803 LE64_BITMASK(BCH_SB_META_REPLICAS_REQ,  struct bch_sb, flags[1], 20, 24);
1804 LE64_BITMASK(BCH_SB_DATA_REPLICAS_REQ,  struct bch_sb, flags[1], 24, 28);
1805
1806 LE64_BITMASK(BCH_SB_PROMOTE_TARGET,     struct bch_sb, flags[1], 28, 40);
1807 LE64_BITMASK(BCH_SB_FOREGROUND_TARGET,  struct bch_sb, flags[1], 40, 52);
1808 LE64_BITMASK(BCH_SB_BACKGROUND_TARGET,  struct bch_sb, flags[1], 52, 64);
1809
1810 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO,
1811                                         struct bch_sb, flags[2],  0,  4);
1812 LE64_BITMASK(BCH_SB_GC_RESERVE_BYTES,   struct bch_sb, flags[2],  4, 64);
1813
1814 LE64_BITMASK(BCH_SB_ERASURE_CODE,       struct bch_sb, flags[3],  0, 16);
1815 LE64_BITMASK(BCH_SB_METADATA_TARGET,    struct bch_sb, flags[3], 16, 28);
1816 LE64_BITMASK(BCH_SB_SHARD_INUMS,        struct bch_sb, flags[3], 28, 29);
1817 LE64_BITMASK(BCH_SB_INODES_USE_KEY_CACHE,struct bch_sb, flags[3], 29, 30);
1818 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DELAY,struct bch_sb, flags[3], 30, 62);
1819 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DISABLED,struct bch_sb, flags[3], 62, 63);
1820 LE64_BITMASK(BCH_SB_JOURNAL_RECLAIM_DELAY,struct bch_sb, flags[4], 0, 32);
1821 LE64_BITMASK(BCH_SB_JOURNAL_TRANSACTION_NAMES,struct bch_sb, flags[4], 32, 33);
1822 LE64_BITMASK(BCH_SB_NOCOW,              struct bch_sb, flags[4], 33, 34);
1823 LE64_BITMASK(BCH_SB_WRITE_BUFFER_SIZE,  struct bch_sb, flags[4], 34, 54);
1824 LE64_BITMASK(BCH_SB_VERSION_UPGRADE,    struct bch_sb, flags[4], 54, 56);
1825
1826 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_HI,struct bch_sb, flags[4], 56, 60);
1827 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI,
1828                                         struct bch_sb, flags[4], 60, 64);
1829
1830 LE64_BITMASK(BCH_SB_VERSION_UPGRADE_COMPLETE,
1831                                         struct bch_sb, flags[5],  0, 16);
1832
1833 static inline __u64 BCH_SB_COMPRESSION_TYPE(const struct bch_sb *sb)
1834 {
1835         return BCH_SB_COMPRESSION_TYPE_LO(sb) | (BCH_SB_COMPRESSION_TYPE_HI(sb) << 4);
1836 }
1837
1838 static inline void SET_BCH_SB_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1839 {
1840         SET_BCH_SB_COMPRESSION_TYPE_LO(sb, v);
1841         SET_BCH_SB_COMPRESSION_TYPE_HI(sb, v >> 4);
1842 }
1843
1844 static inline __u64 BCH_SB_BACKGROUND_COMPRESSION_TYPE(const struct bch_sb *sb)
1845 {
1846         return BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb) |
1847                 (BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb) << 4);
1848 }
1849
1850 static inline void SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1851 {
1852         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb, v);
1853         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb, v >> 4);
1854 }
1855
1856 /*
1857  * Features:
1858  *
1859  * journal_seq_blacklist_v3:    gates BCH_SB_FIELD_journal_seq_blacklist
1860  * reflink:                     gates KEY_TYPE_reflink
1861  * inline_data:                 gates KEY_TYPE_inline_data
1862  * new_siphash:                 gates BCH_STR_HASH_siphash
1863  * new_extent_overwrite:        gates BTREE_NODE_NEW_EXTENT_OVERWRITE
1864  */
1865 #define BCH_SB_FEATURES()                       \
1866         x(lz4,                          0)      \
1867         x(gzip,                         1)      \
1868         x(zstd,                         2)      \
1869         x(atomic_nlink,                 3)      \
1870         x(ec,                           4)      \
1871         x(journal_seq_blacklist_v3,     5)      \
1872         x(reflink,                      6)      \
1873         x(new_siphash,                  7)      \
1874         x(inline_data,                  8)      \
1875         x(new_extent_overwrite,         9)      \
1876         x(incompressible,               10)     \
1877         x(btree_ptr_v2,                 11)     \
1878         x(extents_above_btree_updates,  12)     \
1879         x(btree_updates_journalled,     13)     \
1880         x(reflink_inline_data,          14)     \
1881         x(new_varint,                   15)     \
1882         x(journal_no_flush,             16)     \
1883         x(alloc_v2,                     17)     \
1884         x(extents_across_btree_nodes,   18)
1885
1886 #define BCH_SB_FEATURES_ALWAYS                          \
1887         ((1ULL << BCH_FEATURE_new_extent_overwrite)|    \
1888          (1ULL << BCH_FEATURE_extents_above_btree_updates)|\
1889          (1ULL << BCH_FEATURE_btree_updates_journalled)|\
1890          (1ULL << BCH_FEATURE_alloc_v2)|\
1891          (1ULL << BCH_FEATURE_extents_across_btree_nodes))
1892
1893 #define BCH_SB_FEATURES_ALL                             \
1894         (BCH_SB_FEATURES_ALWAYS|                        \
1895          (1ULL << BCH_FEATURE_new_siphash)|             \
1896          (1ULL << BCH_FEATURE_btree_ptr_v2)|            \
1897          (1ULL << BCH_FEATURE_new_varint)|              \
1898          (1ULL << BCH_FEATURE_journal_no_flush))
1899
1900 enum bch_sb_feature {
1901 #define x(f, n) BCH_FEATURE_##f,
1902         BCH_SB_FEATURES()
1903 #undef x
1904         BCH_FEATURE_NR,
1905 };
1906
1907 #define BCH_SB_COMPAT()                                 \
1908         x(alloc_info,                           0)      \
1909         x(alloc_metadata,                       1)      \
1910         x(extents_above_btree_updates_done,     2)      \
1911         x(bformat_overflow_done,                3)
1912
1913 enum bch_sb_compat {
1914 #define x(f, n) BCH_COMPAT_##f,
1915         BCH_SB_COMPAT()
1916 #undef x
1917         BCH_COMPAT_NR,
1918 };
1919
1920 /* options: */
1921
1922 #define BCH_VERSION_UPGRADE_OPTS()      \
1923         x(compatible,           0)      \
1924         x(incompatible,         1)      \
1925         x(none,                 2)
1926
1927 enum bch_version_upgrade_opts {
1928 #define x(t, n) BCH_VERSION_UPGRADE_##t = n,
1929         BCH_VERSION_UPGRADE_OPTS()
1930 #undef x
1931 };
1932
1933 #define BCH_REPLICAS_MAX                4U
1934
1935 #define BCH_BKEY_PTRS_MAX               16U
1936
1937 #define BCH_ERROR_ACTIONS()             \
1938         x(continue,             0)      \
1939         x(ro,                   1)      \
1940         x(panic,                2)
1941
1942 enum bch_error_actions {
1943 #define x(t, n) BCH_ON_ERROR_##t = n,
1944         BCH_ERROR_ACTIONS()
1945 #undef x
1946         BCH_ON_ERROR_NR
1947 };
1948
1949 #define BCH_STR_HASH_TYPES()            \
1950         x(crc32c,               0)      \
1951         x(crc64,                1)      \
1952         x(siphash_old,          2)      \
1953         x(siphash,              3)
1954
1955 enum bch_str_hash_type {
1956 #define x(t, n) BCH_STR_HASH_##t = n,
1957         BCH_STR_HASH_TYPES()
1958 #undef x
1959         BCH_STR_HASH_NR
1960 };
1961
1962 #define BCH_STR_HASH_OPTS()             \
1963         x(crc32c,               0)      \
1964         x(crc64,                1)      \
1965         x(siphash,              2)
1966
1967 enum bch_str_hash_opts {
1968 #define x(t, n) BCH_STR_HASH_OPT_##t = n,
1969         BCH_STR_HASH_OPTS()
1970 #undef x
1971         BCH_STR_HASH_OPT_NR
1972 };
1973
1974 #define BCH_CSUM_TYPES()                        \
1975         x(none,                         0)      \
1976         x(crc32c_nonzero,               1)      \
1977         x(crc64_nonzero,                2)      \
1978         x(chacha20_poly1305_80,         3)      \
1979         x(chacha20_poly1305_128,        4)      \
1980         x(crc32c,                       5)      \
1981         x(crc64,                        6)      \
1982         x(xxhash,                       7)
1983
1984 enum bch_csum_type {
1985 #define x(t, n) BCH_CSUM_##t = n,
1986         BCH_CSUM_TYPES()
1987 #undef x
1988         BCH_CSUM_NR
1989 };
1990
1991 static const __maybe_unused unsigned bch_crc_bytes[] = {
1992         [BCH_CSUM_none]                         = 0,
1993         [BCH_CSUM_crc32c_nonzero]               = 4,
1994         [BCH_CSUM_crc32c]                       = 4,
1995         [BCH_CSUM_crc64_nonzero]                = 8,
1996         [BCH_CSUM_crc64]                        = 8,
1997         [BCH_CSUM_xxhash]                       = 8,
1998         [BCH_CSUM_chacha20_poly1305_80]         = 10,
1999         [BCH_CSUM_chacha20_poly1305_128]        = 16,
2000 };
2001
2002 static inline _Bool bch2_csum_type_is_encryption(enum bch_csum_type type)
2003 {
2004         switch (type) {
2005         case BCH_CSUM_chacha20_poly1305_80:
2006         case BCH_CSUM_chacha20_poly1305_128:
2007                 return true;
2008         default:
2009                 return false;
2010         }
2011 }
2012
2013 #define BCH_CSUM_OPTS()                 \
2014         x(none,                 0)      \
2015         x(crc32c,               1)      \
2016         x(crc64,                2)      \
2017         x(xxhash,               3)
2018
2019 enum bch_csum_opts {
2020 #define x(t, n) BCH_CSUM_OPT_##t = n,
2021         BCH_CSUM_OPTS()
2022 #undef x
2023         BCH_CSUM_OPT_NR
2024 };
2025
2026 #define BCH_COMPRESSION_TYPES()         \
2027         x(none,                 0)      \
2028         x(lz4_old,              1)      \
2029         x(gzip,                 2)      \
2030         x(lz4,                  3)      \
2031         x(zstd,                 4)      \
2032         x(incompressible,       5)
2033
2034 enum bch_compression_type {
2035 #define x(t, n) BCH_COMPRESSION_TYPE_##t = n,
2036         BCH_COMPRESSION_TYPES()
2037 #undef x
2038         BCH_COMPRESSION_TYPE_NR
2039 };
2040
2041 #define BCH_COMPRESSION_OPTS()          \
2042         x(none,         0)              \
2043         x(lz4,          1)              \
2044         x(gzip,         2)              \
2045         x(zstd,         3)
2046
2047 enum bch_compression_opts {
2048 #define x(t, n) BCH_COMPRESSION_OPT_##t = n,
2049         BCH_COMPRESSION_OPTS()
2050 #undef x
2051         BCH_COMPRESSION_OPT_NR
2052 };
2053
2054 /*
2055  * Magic numbers
2056  *
2057  * The various other data structures have their own magic numbers, which are
2058  * xored with the first part of the cache set's UUID
2059  */
2060
2061 #define BCACHE_MAGIC                                                    \
2062         UUID_INIT(0xc68573f6, 0x4e1a, 0x45ca,                           \
2063                   0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81)
2064 #define BCHFS_MAGIC                                                     \
2065         UUID_INIT(0xc68573f6, 0x66ce, 0x90a9,                           \
2066                   0xd9, 0x6a, 0x60, 0xcf, 0x80, 0x3d, 0xf7, 0xef)
2067
2068 #define BCACHEFS_STATFS_MAGIC           0xca451a4e
2069
2070 #define JSET_MAGIC              __cpu_to_le64(0x245235c1a3625032ULL)
2071 #define BSET_MAGIC              __cpu_to_le64(0x90135c78b99e07f5ULL)
2072
2073 static inline __le64 __bch2_sb_magic(struct bch_sb *sb)
2074 {
2075         __le64 ret;
2076
2077         memcpy(&ret, &sb->uuid, sizeof(ret));
2078         return ret;
2079 }
2080
2081 static inline __u64 __jset_magic(struct bch_sb *sb)
2082 {
2083         return __le64_to_cpu(__bch2_sb_magic(sb) ^ JSET_MAGIC);
2084 }
2085
2086 static inline __u64 __bset_magic(struct bch_sb *sb)
2087 {
2088         return __le64_to_cpu(__bch2_sb_magic(sb) ^ BSET_MAGIC);
2089 }
2090
2091 /* Journal */
2092
2093 #define JSET_KEYS_U64s  (sizeof(struct jset_entry) / sizeof(__u64))
2094
2095 #define BCH_JSET_ENTRY_TYPES()                  \
2096         x(btree_keys,           0)              \
2097         x(btree_root,           1)              \
2098         x(prio_ptrs,            2)              \
2099         x(blacklist,            3)              \
2100         x(blacklist_v2,         4)              \
2101         x(usage,                5)              \
2102         x(data_usage,           6)              \
2103         x(clock,                7)              \
2104         x(dev_usage,            8)              \
2105         x(log,                  9)              \
2106         x(overwrite,            10)
2107
2108 enum {
2109 #define x(f, nr)        BCH_JSET_ENTRY_##f      = nr,
2110         BCH_JSET_ENTRY_TYPES()
2111 #undef x
2112         BCH_JSET_ENTRY_NR
2113 };
2114
2115 /*
2116  * Journal sequence numbers can be blacklisted: bsets record the max sequence
2117  * number of all the journal entries they contain updates for, so that on
2118  * recovery we can ignore those bsets that contain index updates newer that what
2119  * made it into the journal.
2120  *
2121  * This means that we can't reuse that journal_seq - we have to skip it, and
2122  * then record that we skipped it so that the next time we crash and recover we
2123  * don't think there was a missing journal entry.
2124  */
2125 struct jset_entry_blacklist {
2126         struct jset_entry       entry;
2127         __le64                  seq;
2128 };
2129
2130 struct jset_entry_blacklist_v2 {
2131         struct jset_entry       entry;
2132         __le64                  start;
2133         __le64                  end;
2134 };
2135
2136 #define BCH_FS_USAGE_TYPES()                    \
2137         x(reserved,             0)              \
2138         x(inodes,               1)              \
2139         x(key_version,          2)
2140
2141 enum {
2142 #define x(f, nr)        BCH_FS_USAGE_##f        = nr,
2143         BCH_FS_USAGE_TYPES()
2144 #undef x
2145         BCH_FS_USAGE_NR
2146 };
2147
2148 struct jset_entry_usage {
2149         struct jset_entry       entry;
2150         __le64                  v;
2151 } __packed;
2152
2153 struct jset_entry_data_usage {
2154         struct jset_entry       entry;
2155         __le64                  v;
2156         struct bch_replicas_entry r;
2157 } __packed;
2158
2159 struct jset_entry_clock {
2160         struct jset_entry       entry;
2161         __u8                    rw;
2162         __u8                    pad[7];
2163         __le64                  time;
2164 } __packed;
2165
2166 struct jset_entry_dev_usage_type {
2167         __le64                  buckets;
2168         __le64                  sectors;
2169         __le64                  fragmented;
2170 } __packed;
2171
2172 struct jset_entry_dev_usage {
2173         struct jset_entry       entry;
2174         __le32                  dev;
2175         __u32                   pad;
2176
2177         __le64                  buckets_ec;
2178         __le64                  _buckets_unavailable; /* No longer used */
2179
2180         struct jset_entry_dev_usage_type d[];
2181 };
2182
2183 static inline unsigned jset_entry_dev_usage_nr_types(struct jset_entry_dev_usage *u)
2184 {
2185         return (vstruct_bytes(&u->entry) - sizeof(struct jset_entry_dev_usage)) /
2186                 sizeof(struct jset_entry_dev_usage_type);
2187 }
2188
2189 struct jset_entry_log {
2190         struct jset_entry       entry;
2191         u8                      d[];
2192 } __packed;
2193
2194 /*
2195  * On disk format for a journal entry:
2196  * seq is monotonically increasing; every journal entry has its own unique
2197  * sequence number.
2198  *
2199  * last_seq is the oldest journal entry that still has keys the btree hasn't
2200  * flushed to disk yet.
2201  *
2202  * version is for on disk format changes.
2203  */
2204 struct jset {
2205         struct bch_csum         csum;
2206
2207         __le64                  magic;
2208         __le64                  seq;
2209         __le32                  version;
2210         __le32                  flags;
2211
2212         __le32                  u64s; /* size of d[] in u64s */
2213
2214         __u8                    encrypted_start[0];
2215
2216         __le16                  _read_clock; /* no longer used */
2217         __le16                  _write_clock;
2218
2219         /* Sequence number of oldest dirty journal entry */
2220         __le64                  last_seq;
2221
2222
2223         struct jset_entry       start[0];
2224         __u64                   _data[];
2225 } __packed __aligned(8);
2226
2227 LE32_BITMASK(JSET_CSUM_TYPE,    struct jset, flags, 0, 4);
2228 LE32_BITMASK(JSET_BIG_ENDIAN,   struct jset, flags, 4, 5);
2229 LE32_BITMASK(JSET_NO_FLUSH,     struct jset, flags, 5, 6);
2230
2231 #define BCH_JOURNAL_BUCKETS_MIN         8
2232
2233 /* Btree: */
2234
2235 enum btree_id_flags {
2236         BTREE_ID_EXTENTS        = BIT(0),
2237         BTREE_ID_SNAPSHOTS      = BIT(1),
2238         BTREE_ID_DATA           = BIT(2),
2239 };
2240
2241 #define BCH_BTREE_IDS()                                                         \
2242         x(extents,              0,      BTREE_ID_EXTENTS|BTREE_ID_SNAPSHOTS|BTREE_ID_DATA,\
2243           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2244           BIT_ULL(KEY_TYPE_error)|                                              \
2245           BIT_ULL(KEY_TYPE_cookie)|                                             \
2246           BIT_ULL(KEY_TYPE_extent)|                                             \
2247           BIT_ULL(KEY_TYPE_reservation)|                                        \
2248           BIT_ULL(KEY_TYPE_reflink_p)|                                          \
2249           BIT_ULL(KEY_TYPE_inline_data))                                        \
2250         x(inodes,               1,      BTREE_ID_SNAPSHOTS,                     \
2251           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2252           BIT_ULL(KEY_TYPE_inode)|                                              \
2253           BIT_ULL(KEY_TYPE_inode_v2)|                                           \
2254           BIT_ULL(KEY_TYPE_inode_v3)|                                           \
2255           BIT_ULL(KEY_TYPE_inode_generation))                                   \
2256         x(dirents,              2,      BTREE_ID_SNAPSHOTS,                     \
2257           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2258           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
2259           BIT_ULL(KEY_TYPE_dirent))                                             \
2260         x(xattrs,               3,      BTREE_ID_SNAPSHOTS,                     \
2261           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2262           BIT_ULL(KEY_TYPE_cookie)|                                             \
2263           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
2264           BIT_ULL(KEY_TYPE_xattr))                                              \
2265         x(alloc,                4,      0,                                      \
2266           BIT_ULL(KEY_TYPE_alloc)|                                              \
2267           BIT_ULL(KEY_TYPE_alloc_v2)|                                           \
2268           BIT_ULL(KEY_TYPE_alloc_v3)|                                           \
2269           BIT_ULL(KEY_TYPE_alloc_v4))                                           \
2270         x(quotas,               5,      0,                                      \
2271           BIT_ULL(KEY_TYPE_quota))                                              \
2272         x(stripes,              6,      0,                                      \
2273           BIT_ULL(KEY_TYPE_stripe))                                             \
2274         x(reflink,              7,      BTREE_ID_EXTENTS|BTREE_ID_DATA,         \
2275           BIT_ULL(KEY_TYPE_reflink_v)|                                          \
2276           BIT_ULL(KEY_TYPE_indirect_inline_data))                               \
2277         x(subvolumes,           8,      0,                                      \
2278           BIT_ULL(KEY_TYPE_subvolume))                                          \
2279         x(snapshots,            9,      0,                                      \
2280           BIT_ULL(KEY_TYPE_snapshot))                                           \
2281         x(lru,                  10,     0,                                      \
2282           BIT_ULL(KEY_TYPE_set))                                                \
2283         x(freespace,            11,     BTREE_ID_EXTENTS,                       \
2284           BIT_ULL(KEY_TYPE_set))                                                \
2285         x(need_discard,         12,     0,                                      \
2286           BIT_ULL(KEY_TYPE_set))                                                \
2287         x(backpointers,         13,     0,                                      \
2288           BIT_ULL(KEY_TYPE_backpointer))                                        \
2289         x(bucket_gens,          14,     0,                                      \
2290           BIT_ULL(KEY_TYPE_bucket_gens))                                        \
2291         x(snapshot_trees,       15,     0,                                      \
2292           BIT_ULL(KEY_TYPE_snapshot_tree))                                      \
2293         x(deleted_inodes,       16,     BTREE_ID_SNAPSHOTS,                     \
2294           BIT_ULL(KEY_TYPE_set))                                                \
2295         x(logged_ops,           17,     0,                                      \
2296           BIT_ULL(KEY_TYPE_logged_op_truncate)|                                 \
2297           BIT_ULL(KEY_TYPE_logged_op_finsert))                                  \
2298         x(rebalance_work,       18,     BTREE_ID_SNAPSHOTS,                     \
2299           BIT_ULL(KEY_TYPE_set)|BIT_ULL(KEY_TYPE_cookie))
2300
2301 enum btree_id {
2302 #define x(name, nr, ...) BTREE_ID_##name = nr,
2303         BCH_BTREE_IDS()
2304 #undef x
2305         BTREE_ID_NR
2306 };
2307
2308 #define BTREE_MAX_DEPTH         4U
2309
2310 /* Btree nodes */
2311
2312 /*
2313  * Btree nodes
2314  *
2315  * On disk a btree node is a list/log of these; within each set the keys are
2316  * sorted
2317  */
2318 struct bset {
2319         __le64                  seq;
2320
2321         /*
2322          * Highest journal entry this bset contains keys for.
2323          * If on recovery we don't see that journal entry, this bset is ignored:
2324          * this allows us to preserve the order of all index updates after a
2325          * crash, since the journal records a total order of all index updates
2326          * and anything that didn't make it to the journal doesn't get used.
2327          */
2328         __le64                  journal_seq;
2329
2330         __le32                  flags;
2331         __le16                  version;
2332         __le16                  u64s; /* count of d[] in u64s */
2333
2334         struct bkey_packed      start[0];
2335         __u64                   _data[];
2336 } __packed __aligned(8);
2337
2338 LE32_BITMASK(BSET_CSUM_TYPE,    struct bset, flags, 0, 4);
2339
2340 LE32_BITMASK(BSET_BIG_ENDIAN,   struct bset, flags, 4, 5);
2341 LE32_BITMASK(BSET_SEPARATE_WHITEOUTS,
2342                                 struct bset, flags, 5, 6);
2343
2344 /* Sector offset within the btree node: */
2345 LE32_BITMASK(BSET_OFFSET,       struct bset, flags, 16, 32);
2346
2347 struct btree_node {
2348         struct bch_csum         csum;
2349         __le64                  magic;
2350
2351         /* this flags field is encrypted, unlike bset->flags: */
2352         __le64                  flags;
2353
2354         /* Closed interval: */
2355         struct bpos             min_key;
2356         struct bpos             max_key;
2357         struct bch_extent_ptr   _ptr; /* not used anymore */
2358         struct bkey_format      format;
2359
2360         union {
2361         struct bset             keys;
2362         struct {
2363                 __u8            pad[22];
2364                 __le16          u64s;
2365                 __u64           _data[0];
2366
2367         };
2368         };
2369 } __packed __aligned(8);
2370
2371 LE64_BITMASK(BTREE_NODE_ID_LO,  struct btree_node, flags,  0,  4);
2372 LE64_BITMASK(BTREE_NODE_LEVEL,  struct btree_node, flags,  4,  8);
2373 LE64_BITMASK(BTREE_NODE_NEW_EXTENT_OVERWRITE,
2374                                 struct btree_node, flags,  8,  9);
2375 LE64_BITMASK(BTREE_NODE_ID_HI,  struct btree_node, flags,  9, 25);
2376 /* 25-32 unused */
2377 LE64_BITMASK(BTREE_NODE_SEQ,    struct btree_node, flags, 32, 64);
2378
2379 static inline __u64 BTREE_NODE_ID(struct btree_node *n)
2380 {
2381         return BTREE_NODE_ID_LO(n) | (BTREE_NODE_ID_HI(n) << 4);
2382 }
2383
2384 static inline void SET_BTREE_NODE_ID(struct btree_node *n, __u64 v)
2385 {
2386         SET_BTREE_NODE_ID_LO(n, v);
2387         SET_BTREE_NODE_ID_HI(n, v >> 4);
2388 }
2389
2390 struct btree_node_entry {
2391         struct bch_csum         csum;
2392
2393         union {
2394         struct bset             keys;
2395         struct {
2396                 __u8            pad[22];
2397                 __le16          u64s;
2398                 __u64           _data[0];
2399         };
2400         };
2401 } __packed __aligned(8);
2402
2403 #endif /* _BCACHEFS_FORMAT_H */