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