fs/bcachefs/bcachefs_format.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _BCACHEFS_FORMAT_H
   3 #define _BCACHEFS_FORMAT_H
   4
   5 /*
   6  * bcachefs on disk data structures
   7  *
   8  * OVERVIEW:
   9  *
  10  * There are three main types of on disk data structures in bcachefs (this is
  11  * reduced from 5 in bcache)
  12  *
  13  *  - superblock
  14  *  - journal
  15  *  - btree
  16  *
  17  * The btree is the primary structure; most metadata exists as keys in the
  18  * various btrees. There are only a small number of btrees, they're not
  19  * sharded - we have one btree for extents, another for inodes, et cetera.
  20  *
  21  * SUPERBLOCK:
  22  *
  23  * The superblock contains the location of the journal, the list of devices in
  24  * the filesystem, and in general any metadata we need in order to decide
  25  * whether we can start a filesystem or prior to reading the journal/btree
  26  * roots.
  27  *
  28  * The superblock is extensible, and most of the contents of the superblock are
  29  * in variable length, type tagged fields; see struct bch_sb_field.
  30  *
  31  * Backup superblocks do not reside in a fixed location; also, superblocks do
  32  * not have a fixed size. To locate backup superblocks we have struct
  33  * bch_sb_layout; we store a copy of this inside every superblock, and also
  34  * before the first superblock.
  35  *
  36  * JOURNAL:
  37  *
  38  * The journal primarily records btree updates in the order they occurred;
  39  * journal replay consists of just iterating over all the keys in the open
  40  * journal entries and re-inserting them into the btrees.
  41  *
  42  * The journal also contains entry types for the btree roots, and blacklisted
  43  * journal sequence numbers (see journal_seq_blacklist.c).
  44  *
  45  * BTREE:
  46  *
  47  * bcachefs btrees are copy on write b+ trees, where nodes are big (typically
  48  * 128k-256k) and log structured. We use struct btree_node for writing the first
  49  * entry in a given node (offset 0), and struct btree_node_entry for all
  50  * subsequent writes.
  51  *
  52  * After the header, btree node entries contain a list of keys in sorted order.
  53  * Values are stored inline with the keys; since values are variable length (and
  54  * keys effectively are variable length too, due to packing) we can't do random
  55  * access without building up additional in memory tables in the btree node read
  56  * path.
  57  *
  58  * BTREE KEYS (struct bkey):
  59  *
  60  * The various btrees share a common format for the key - so as to avoid
  61  * switching in fastpath lookup/comparison code - but define their own
  62  * structures for the key values.
  63  *
  64  * The size of a key/value pair is stored as a u8 in units of u64s, so the max
  65  * size is just under 2k. The common part also contains a type tag for the
  66  * value, and a format field indicating whether the key is packed or not (and
  67  * also meant to allow adding new key fields in the future, if desired).
  68  *
  69  * bkeys, when stored within a btree node, may also be packed. In that case, the
  70  * bkey_format in that node is used to unpack it. Packed bkeys mean that we can
  71  * be generous with field sizes in the common part of the key format (64 bit
  72  * inode number, 64 bit offset, 96 bit version field, etc.) for negligible cost.
  73  */
  74
  75 #include <asm/types.h>
  76 #include <asm/byteorder.h>
  77 #include <linux/kernel.h>
  78 #include <linux/uuid.h>
  79 #include "vstructs.h"
  80
  81 #ifdef __KERNEL__
  82 typedef uuid_t __uuid_t;
  83 #endif
  84
  85 #define BITMASK(name, type, field, offset, end)                         \
  86 static const __maybe_unused unsigned    name##_OFFSET = offset;         \
  87 static const __maybe_unused unsigned    name##_BITS = (end - offset);   \
  88                                                                         \
  89 static inline __u64 name(const type *k)                                 \
  90 {                                                                       \
  91         return (k->field >> offset) & ~(~0ULL << (end - offset));       \
  92 }                                                                       \
  93                                                                         \
  94 static inline void SET_##name(type *k, __u64 v)                         \
  95 {                                                                       \
  96         k->field &= ~(~(~0ULL << (end - offset)) << offset);            \
  97         k->field |= (v & ~(~0ULL << (end - offset))) << offset;         \
  98 }
  99
 100 #define LE_BITMASK(_bits, name, type, field, offset, end)               \
 101 static const __maybe_unused unsigned    name##_OFFSET = offset;         \
 102 static const __maybe_unused unsigned    name##_BITS = (end - offset);   \
 103 static const __maybe_unused __u##_bits  name##_MAX = (1ULL << (end - offset)) - 1;\
 104                                                                         \
 105 static inline __u64 name(const type *k)                                 \
 106 {                                                                       \
 107         return (__le##_bits##_to_cpu(k->field) >> offset) &             \
 108                 ~(~0ULL << (end - offset));                             \
 109 }                                                                       \
 110                                                                         \
 111 static inline void SET_##name(type *k, __u64 v)                         \
 112 {                                                                       \
 113         __u##_bits new = __le##_bits##_to_cpu(k->field);                \
 114                                                                         \
 115         new &= ~(~(~0ULL << (end - offset)) << offset);                 \
 116         new |= (v & ~(~0ULL << (end - offset))) << offset;              \
 117         k->field = __cpu_to_le##_bits(new);                             \
 118 }
 119
 120 #define LE16_BITMASK(n, t, f, o, e)     LE_BITMASK(16, n, t, f, o, e)
 121 #define LE32_BITMASK(n, t, f, o, e)     LE_BITMASK(32, n, t, f, o, e)
 122 #define LE64_BITMASK(n, t, f, o, e)     LE_BITMASK(64, n, t, f, o, e)
 123
 124 struct bkey_format {
 125         __u8            key_u64s;
 126         __u8            nr_fields;
 127         /* One unused slot for now: */
 128         __u8            bits_per_field[6];
 129         __le64          field_offset[6];
 130 };
 131
 132 /* Btree keys - all units are in sectors */
 133
 134 struct bpos {
 135         /*
 136          * Word order matches machine byte order - btree code treats a bpos as a
 137          * single large integer, for search/comparison purposes
 138          *
 139          * Note that wherever a bpos is embedded in another on disk data
 140          * structure, it has to be byte swabbed when reading in metadata that
 141          * wasn't written in native endian order:
 142          */
 143 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 144         __u32           snapshot;
 145         __u64           offset;
 146         __u64           inode;
 147 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 148         __u64           inode;
 149         __u64           offset;         /* Points to end of extent - sectors */
 150         __u32           snapshot;
 151 #else
 152 #error edit for your odd byteorder.
 153 #endif
 154 } __packed
 155 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 156 __aligned(4)
 157 #endif
 158 ;
 159
 160 #define KEY_INODE_MAX                   ((__u64)~0ULL)
 161 #define KEY_OFFSET_MAX                  ((__u64)~0ULL)
 162 #define KEY_SNAPSHOT_MAX                ((__u32)~0U)
 163 #define KEY_SIZE_MAX                    ((__u32)~0U)
 164
 165 static inline struct bpos SPOS(__u64 inode, __u64 offset, __u32 snapshot)
 166 {
 167         return (struct bpos) {
 168                 .inode          = inode,
 169                 .offset         = offset,
 170                 .snapshot       = snapshot,
 171         };
 172 }
 173
 174 #define POS_MIN                         SPOS(0, 0, 0)
 175 #define POS_MAX                         SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, 0)
 176 #define SPOS_MAX                        SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, KEY_SNAPSHOT_MAX)
 177 #define POS(_inode, _offset)            SPOS(_inode, _offset, 0)
 178
 179 /* Empty placeholder struct, for container_of() */
 180 struct bch_val {
 181         __u64           __nothing[0];
 182 };
 183
 184 struct bversion {
 185 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 186         __u64           lo;
 187         __u32           hi;
 188 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 189         __u32           hi;
 190         __u64           lo;
 191 #endif
 192 } __packed __aligned(4);
 193
 194 struct bkey {
 195         /* Size of combined key and value, in u64s */
 196         __u8            u64s;
 197
 198         /* Format of key (0 for format local to btree node) */
 199 #if defined(__LITTLE_ENDIAN_BITFIELD)
 200         __u8            format:7,
 201                         needs_whiteout:1;
 202 #elif defined (__BIG_ENDIAN_BITFIELD)
 203         __u8            needs_whiteout:1,
 204                         format:7;
 205 #else
 206 #error edit for your odd byteorder.
 207 #endif
 208
 209         /* Type of the value */
 210         __u8            type;
 211
 212 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 213         __u8            pad[1];
 214
 215         struct bversion version;
 216         __u32           size;           /* extent size, in sectors */
 217         struct bpos     p;
 218 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 219         struct bpos     p;
 220         __u32           size;           /* extent size, in sectors */
 221         struct bversion version;
 222
 223         __u8            pad[1];
 224 #endif
 225 } __packed __aligned(8);
 226
 227 struct bkey_packed {
 228         __u64           _data[0];
 229
 230         /* Size of combined key and value, in u64s */
 231         __u8            u64s;
 232
 233         /* Format of key (0 for format local to btree node) */
 234
 235         /*
 236          * XXX: next incompat on disk format change, switch format and
 237          * needs_whiteout - bkey_packed() will be cheaper if format is the high
 238          * bits of the bitfield
 239          */
 240 #if defined(__LITTLE_ENDIAN_BITFIELD)
 241         __u8            format:7,
 242                         needs_whiteout:1;
 243 #elif defined (__BIG_ENDIAN_BITFIELD)
 244         __u8            needs_whiteout:1,
 245                         format:7;
 246 #endif
 247
 248         /* Type of the value */
 249         __u8            type;
 250         __u8            key_start[0];
 251
 252         /*
 253          * We copy bkeys with struct assignment in various places, and while
 254          * that shouldn't be done with packed bkeys we can't disallow it in C,
 255          * and it's legal to cast a bkey to a bkey_packed  - so padding it out
 256          * to the same size as struct bkey should hopefully be safest.
 257          */
 258         __u8            pad[sizeof(struct bkey) - 3];
 259 } __packed __aligned(8);
 260
 261 typedef struct {
 262         __le64                  lo;
 263         __le64                  hi;
 264 } bch_le128;
 265
 266 #define BKEY_U64s                       (sizeof(struct bkey) / sizeof(__u64))
 267 #define BKEY_U64s_MAX                   U8_MAX
 268 #define BKEY_VAL_U64s_MAX               (BKEY_U64s_MAX - BKEY_U64s)
 269
 270 #define KEY_PACKED_BITS_START           24
 271
 272 #define KEY_FORMAT_LOCAL_BTREE          0
 273 #define KEY_FORMAT_CURRENT              1
 274
 275 enum bch_bkey_fields {
 276         BKEY_FIELD_INODE,
 277         BKEY_FIELD_OFFSET,
 278         BKEY_FIELD_SNAPSHOT,
 279         BKEY_FIELD_SIZE,
 280         BKEY_FIELD_VERSION_HI,
 281         BKEY_FIELD_VERSION_LO,
 282         BKEY_NR_FIELDS,
 283 };
 284
 285 #define bkey_format_field(name, field)                                  \
 286         [BKEY_FIELD_##name] = (sizeof(((struct bkey *) NULL)->field) * 8)
 287
 288 #define BKEY_FORMAT_CURRENT                                             \
 289 ((struct bkey_format) {                                                 \
 290         .key_u64s       = BKEY_U64s,                                    \
 291         .nr_fields      = BKEY_NR_FIELDS,                               \
 292         .bits_per_field = {                                             \
 293                 bkey_format_field(INODE,        p.inode),               \
 294                 bkey_format_field(OFFSET,       p.offset),              \
 295                 bkey_format_field(SNAPSHOT,     p.snapshot),            \
 296                 bkey_format_field(SIZE,         size),                  \
 297                 bkey_format_field(VERSION_HI,   version.hi),            \
 298                 bkey_format_field(VERSION_LO,   version.lo),            \
 299         },                                                              \
 300 })
 301
 302 /* bkey with inline value */
 303 struct bkey_i {
 304         __u64                   _data[0];
 305
 306         struct bkey     k;
 307         struct bch_val  v;
 308 };
 309
 310 #define POS_KEY(_pos)                                                   \
 311 ((struct bkey) {                                                        \
 312         .u64s           = BKEY_U64s,                                    \
 313         .format         = KEY_FORMAT_CURRENT,                           \
 314         .p              = _pos,                                         \
 315 })
 316
 317 #define KEY(_inode, _offset, _size)                                     \
 318 ((struct bkey) {                                                        \
 319         .u64s           = BKEY_U64s,                                    \
 320         .format         = KEY_FORMAT_CURRENT,                           \
 321         .p              = POS(_inode, _offset),                         \
 322         .size           = _size,                                        \
 323 })
 324
 325 static inline void bkey_init(struct bkey *k)
 326 {
 327         *k = KEY(0, 0, 0);
 328 }
 329
 330 #define bkey_bytes(_k)          ((_k)->u64s * sizeof(__u64))
 331
 332 #define __BKEY_PADDED(key, pad)                                 \
 333         struct bkey_i key; __u64 key ## _pad[pad]
 334
 335 /*
 336  * - DELETED keys are used internally to mark keys that should be ignored but
 337  *   override keys in composition order.  Their version number is ignored.
 338  *
 339  * - DISCARDED keys indicate that the data is all 0s because it has been
 340  *   discarded. DISCARDs may have a version; if the version is nonzero the key
 341  *   will be persistent, otherwise the key will be dropped whenever the btree
 342  *   node is rewritten (like DELETED keys).
 343  *
 344  * - ERROR: any read of the data returns a read error, as the data was lost due
 345  *   to a failing device. Like DISCARDED keys, they can be removed (overridden)
 346  *   by new writes or cluster-wide GC. Node repair can also overwrite them with
 347  *   the same or a more recent version number, but not with an older version
 348  *   number.
 349  *
 350  * - WHITEOUT: for hash table btrees
 351  */
 352 #define BCH_BKEY_TYPES()                                \
 353         x(deleted,              0)                      \
 354         x(whiteout,             1)                      \
 355         x(error,                2)                      \
 356         x(cookie,               3)                      \
 357         x(hash_whiteout,        4)                      \
 358         x(btree_ptr,            5)                      \
 359         x(extent,               6)                      \
 360         x(reservation,          7)                      \
 361         x(inode,                8)                      \
 362         x(inode_generation,     9)                      \
 363         x(dirent,               10)                     \
 364         x(xattr,                11)                     \
 365         x(alloc,                12)                     \
 366         x(quota,                13)                     \
 367         x(stripe,               14)                     \
 368         x(reflink_p,            15)                     \
 369         x(reflink_v,            16)                     \
 370         x(inline_data,          17)                     \
 371         x(btree_ptr_v2,         18)                     \
 372         x(indirect_inline_data, 19)                     \
 373         x(alloc_v2,             20)                     \
 374         x(subvolume,            21)                     \
 375         x(snapshot,             22)                     \
 376         x(inode_v2,             23)                     \
 377         x(alloc_v3,             24)                     \
 378         x(set,                  25)                     \
 379         x(lru,                  26)                     \
 380         x(alloc_v4,             27)                     \
 381         x(backpointer,          28)                     \
 382         x(inode_v3,             29)                     \
 383         x(bucket_gens,          30)                     \
 384         x(snapshot_tree,        31)                     \
 385         x(logged_op_truncate,   32)                     \
 386         x(logged_op_finsert,    33)
 387
 388 enum bch_bkey_type {
 389 #define x(name, nr) KEY_TYPE_##name     = nr,
 390         BCH_BKEY_TYPES()
 391 #undef x
 392         KEY_TYPE_MAX,
 393 };
 394
 395 struct bch_deleted {
 396         struct bch_val          v;
 397 };
 398
 399 struct bch_whiteout {
 400         struct bch_val          v;
 401 };
 402
 403 struct bch_error {
 404         struct bch_val          v;
 405 };
 406
 407 struct bch_cookie {
 408         struct bch_val          v;
 409         __le64                  cookie;
 410 };
 411
 412 struct bch_hash_whiteout {
 413         struct bch_val          v;
 414 };
 415
 416 struct bch_set {
 417         struct bch_val          v;
 418 };
 419
 420 /* Extents */
 421
 422 /*
 423  * In extent bkeys, the value is a list of pointers (bch_extent_ptr), optionally
 424  * preceded by checksum/compression information (bch_extent_crc32 or
 425  * bch_extent_crc64).
 426  *
 427  * One major determining factor in the format of extents is how we handle and
 428  * represent extents that have been partially overwritten and thus trimmed:
 429  *
 430  * If an extent is not checksummed or compressed, when the extent is trimmed we
 431  * don't have to remember the extent we originally allocated and wrote: we can
 432  * merely adjust ptr->offset to point to the start of the data that is currently
 433  * live. The size field in struct bkey records the current (live) size of the
 434  * extent, and is also used to mean "size of region on disk that we point to" in
 435  * this case.
 436  *
 437  * Thus an extent that is not checksummed or compressed will consist only of a
 438  * list of bch_extent_ptrs, with none of the fields in
 439  * bch_extent_crc32/bch_extent_crc64.
 440  *
 441  * When an extent is checksummed or compressed, it's not possible to read only
 442  * the data that is currently live: we have to read the entire extent that was
 443  * originally written, and then return only the part of the extent that is
 444  * currently live.
 445  *
 446  * Thus, in addition to the current size of the extent in struct bkey, we need
 447  * to store the size of the originally allocated space - this is the
 448  * compressed_size and uncompressed_size fields in bch_extent_crc32/64. Also,
 449  * when the extent is trimmed, instead of modifying the offset field of the
 450  * pointer, we keep a second smaller offset field - "offset into the original
 451  * extent of the currently live region".
 452  *
 453  * The other major determining factor is replication and data migration:
 454  *
 455  * Each pointer may have its own bch_extent_crc32/64. When doing a replicated
 456  * write, we will initially write all the replicas in the same format, with the
 457  * same checksum type and compression format - however, when copygc runs later (or
 458  * tiering/cache promotion, anything that moves data), it is not in general
 459  * going to rewrite all the pointers at once - one of the replicas may be in a
 460  * bucket on one device that has very little fragmentation while another lives
 461  * in a bucket that has become heavily fragmented, and thus is being rewritten
 462  * sooner than the rest.
 463  *
 464  * Thus it will only move a subset of the pointers (or in the case of
 465  * tiering/cache promotion perhaps add a single pointer without dropping any
 466  * current pointers), and if the extent has been partially overwritten it must
 467  * write only the currently live portion (or copygc would not be able to reduce
 468  * fragmentation!) - which necessitates a different bch_extent_crc format for
 469  * the new pointer.
 470  *
 471  * But in the interests of space efficiency, we don't want to store one
 472  * bch_extent_crc for each pointer if we don't have to.
 473  *
 474  * Thus, a bch_extent consists of bch_extent_crc32s, bch_extent_crc64s, and
 475  * bch_extent_ptrs appended arbitrarily one after the other. We determine the
 476  * type of a given entry with a scheme similar to utf8 (except we're encoding a
 477  * type, not a size), encoding the type in the position of the first set bit:
 478  *
 479  * bch_extent_crc32     - 0b1
 480  * bch_extent_ptr       - 0b10
 481  * bch_extent_crc64     - 0b100
 482  *
 483  * We do it this way because bch_extent_crc32 is _very_ constrained on bits (and
 484  * bch_extent_crc64 is the least constrained).
 485  *
 486  * Then, each bch_extent_crc32/64 applies to the pointers that follow after it,
 487  * until the next bch_extent_crc32/64.
 488  *
 489  * If there are no bch_extent_crcs preceding a bch_extent_ptr, then that pointer
 490  * is neither checksummed nor compressed.
 491  */
 492
 493 /* 128 bits, sufficient for cryptographic MACs: */
 494 struct bch_csum {
 495         __le64                  lo;
 496         __le64                  hi;
 497 } __packed __aligned(8);
 498
 499 #define BCH_EXTENT_ENTRY_TYPES()                \
 500         x(ptr,                  0)              \
 501         x(crc32,                1)              \
 502         x(crc64,                2)              \
 503         x(crc128,               3)              \
 504         x(stripe_ptr,           4)              \
 505         x(rebalance,            5)
 506 #define BCH_EXTENT_ENTRY_MAX    6
 507
 508 enum bch_extent_entry_type {
 509 #define x(f, n) BCH_EXTENT_ENTRY_##f = n,
 510         BCH_EXTENT_ENTRY_TYPES()
 511 #undef x
 512 };
 513
 514 /* Compressed/uncompressed size are stored biased by 1: */
 515 struct bch_extent_crc32 {
 516 #if defined(__LITTLE_ENDIAN_BITFIELD)
 517         __u32                   type:2,
 518                                 _compressed_size:7,
 519                                 _uncompressed_size:7,
 520                                 offset:7,
 521                                 _unused:1,
 522                                 csum_type:4,
 523                                 compression_type:4;
 524         __u32                   csum;
 525 #elif defined (__BIG_ENDIAN_BITFIELD)
 526         __u32                   csum;
 527         __u32                   compression_type:4,
 528                                 csum_type:4,
 529                                 _unused:1,
 530                                 offset:7,
 531                                 _uncompressed_size:7,
 532                                 _compressed_size:7,
 533                                 type:2;
 534 #endif
 535 } __packed __aligned(8);
 536
 537 #define CRC32_SIZE_MAX          (1U << 7)
 538 #define CRC32_NONCE_MAX         0
 539
 540 struct bch_extent_crc64 {
 541 #if defined(__LITTLE_ENDIAN_BITFIELD)
 542         __u64                   type:3,
 543                                 _compressed_size:9,
 544                                 _uncompressed_size:9,
 545                                 offset:9,
 546                                 nonce:10,
 547                                 csum_type:4,
 548                                 compression_type:4,
 549                                 csum_hi:16;
 550 #elif defined (__BIG_ENDIAN_BITFIELD)
 551         __u64                   csum_hi:16,
 552                                 compression_type:4,
 553                                 csum_type:4,
 554                                 nonce:10,
 555                                 offset:9,
 556                                 _uncompressed_size:9,
 557                                 _compressed_size:9,
 558                                 type:3;
 559 #endif
 560         __u64                   csum_lo;
 561 } __packed __aligned(8);
 562
 563 #define CRC64_SIZE_MAX          (1U << 9)
 564 #define CRC64_NONCE_MAX         ((1U << 10) - 1)
 565
 566 struct bch_extent_crc128 {
 567 #if defined(__LITTLE_ENDIAN_BITFIELD)
 568         __u64                   type:4,
 569                                 _compressed_size:13,
 570                                 _uncompressed_size:13,
 571                                 offset:13,
 572                                 nonce:13,
 573                                 csum_type:4,
 574                                 compression_type:4;
 575 #elif defined (__BIG_ENDIAN_BITFIELD)
 576         __u64                   compression_type:4,
 577                                 csum_type:4,
 578                                 nonce:13,
 579                                 offset:13,
 580                                 _uncompressed_size:13,
 581                                 _compressed_size:13,
 582                                 type:4;
 583 #endif
 584         struct bch_csum         csum;
 585 } __packed __aligned(8);
 586
 587 #define CRC128_SIZE_MAX         (1U << 13)
 588 #define CRC128_NONCE_MAX        ((1U << 13) - 1)
 589
 590 /*
 591  * @reservation - pointer hasn't been written to, just reserved
 592  */
 593 struct bch_extent_ptr {
 594 #if defined(__LITTLE_ENDIAN_BITFIELD)
 595         __u64                   type:1,
 596                                 cached:1,
 597                                 unused:1,
 598                                 unwritten:1,
 599                                 offset:44, /* 8 petabytes */
 600                                 dev:8,
 601                                 gen:8;
 602 #elif defined (__BIG_ENDIAN_BITFIELD)
 603         __u64                   gen:8,
 604                                 dev:8,
 605                                 offset:44,
 606                                 unwritten:1,
 607                                 unused:1,
 608                                 cached:1,
 609                                 type:1;
 610 #endif
 611 } __packed __aligned(8);
 612
 613 struct bch_extent_stripe_ptr {
 614 #if defined(__LITTLE_ENDIAN_BITFIELD)
 615         __u64                   type:5,
 616                                 block:8,
 617                                 redundancy:4,
 618                                 idx:47;
 619 #elif defined (__BIG_ENDIAN_BITFIELD)
 620         __u64                   idx:47,
 621                                 redundancy:4,
 622                                 block:8,
 623                                 type:5;
 624 #endif
 625 };
 626
 627 struct bch_extent_rebalance {
 628 #if defined(__LITTLE_ENDIAN_BITFIELD)
 629         __u64                   type:6,
 630                                 unused:34,
 631                                 compression:8, /* enum bch_compression_opt */
 632                                 target:16;
 633 #elif defined (__BIG_ENDIAN_BITFIELD)
 634         __u64                   target:16,
 635                                 compression:8,
 636                                 unused:34,
 637                                 type:6;
 638 #endif
 639 };
 640
 641 union bch_extent_entry {
 642 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ||  __BITS_PER_LONG == 64
 643         unsigned long                   type;
 644 #elif __BITS_PER_LONG == 32
 645         struct {
 646                 unsigned long           pad;
 647                 unsigned long           type;
 648         };
 649 #else
 650 #error edit for your odd byteorder.
 651 #endif
 652
 653 #define x(f, n) struct bch_extent_##f   f;
 654         BCH_EXTENT_ENTRY_TYPES()
 655 #undef x
 656 };
 657
 658 struct bch_btree_ptr {
 659         struct bch_val          v;
 660
 661         __u64                   _data[0];
 662         struct bch_extent_ptr   start[];
 663 } __packed __aligned(8);
 664
 665 struct bch_btree_ptr_v2 {
 666         struct bch_val          v;
 667
 668         __u64                   mem_ptr;
 669         __le64                  seq;
 670         __le16                  sectors_written;
 671         __le16                  flags;
 672         struct bpos             min_key;
 673         __u64                   _data[0];
 674         struct bch_extent_ptr   start[];
 675 } __packed __aligned(8);
 676
 677 LE16_BITMASK(BTREE_PTR_RANGE_UPDATED,   struct bch_btree_ptr_v2, flags, 0, 1);
 678
 679 struct bch_extent {
 680         struct bch_val          v;
 681
 682         __u64                   _data[0];
 683         union bch_extent_entry  start[];
 684 } __packed __aligned(8);
 685
 686 struct bch_reservation {
 687         struct bch_val          v;
 688
 689         __le32                  generation;
 690         __u8                    nr_replicas;
 691         __u8                    pad[3];
 692 } __packed __aligned(8);
 693
 694 /* Maximum size (in u64s) a single pointer could be: */
 695 #define BKEY_EXTENT_PTR_U64s_MAX\
 696         ((sizeof(struct bch_extent_crc128) +                    \
 697           sizeof(struct bch_extent_ptr)) / sizeof(__u64))
 698
 699 /* Maximum possible size of an entire extent value: */
 700 #define BKEY_EXTENT_VAL_U64s_MAX                                \
 701         (1 + BKEY_EXTENT_PTR_U64s_MAX * (BCH_REPLICAS_MAX + 1))
 702
 703 /* * Maximum possible size of an entire extent, key + value: */
 704 #define BKEY_EXTENT_U64s_MAX            (BKEY_U64s + BKEY_EXTENT_VAL_U64s_MAX)
 705
 706 /* Btree pointers don't carry around checksums: */
 707 #define BKEY_BTREE_PTR_VAL_U64s_MAX                             \
 708         ((sizeof(struct bch_btree_ptr_v2) +                     \
 709           sizeof(struct bch_extent_ptr) * BCH_REPLICAS_MAX) / sizeof(__u64))
 710 #define BKEY_BTREE_PTR_U64s_MAX                                 \
 711         (BKEY_U64s + BKEY_BTREE_PTR_VAL_U64s_MAX)
 712
 713 /* Inodes */
 714
 715 #define BLOCKDEV_INODE_MAX      4096
 716
 717 #define BCACHEFS_ROOT_INO       4096
 718
 719 struct bch_inode {
 720         struct bch_val          v;
 721
 722         __le64                  bi_hash_seed;
 723         __le32                  bi_flags;
 724         __le16                  bi_mode;
 725         __u8                    fields[];
 726 } __packed __aligned(8);
 727
 728 struct bch_inode_v2 {
 729         struct bch_val          v;
 730
 731         __le64                  bi_journal_seq;
 732         __le64                  bi_hash_seed;
 733         __le64                  bi_flags;
 734         __le16                  bi_mode;
 735         __u8                    fields[];
 736 } __packed __aligned(8);
 737
 738 struct bch_inode_v3 {
 739         struct bch_val          v;
 740
 741         __le64                  bi_journal_seq;
 742         __le64                  bi_hash_seed;
 743         __le64                  bi_flags;
 744         __le64                  bi_sectors;
 745         __le64                  bi_size;
 746         __le64                  bi_version;
 747         __u8                    fields[];
 748 } __packed __aligned(8);
 749
 750 #define INODEv3_FIELDS_START_INITIAL    6
 751 #define INODEv3_FIELDS_START_CUR        (offsetof(struct bch_inode_v3, fields) / sizeof(__u64))
 752
 753 struct bch_inode_generation {
 754         struct bch_val          v;
 755
 756         __le32                  bi_generation;
 757         __le32                  pad;
 758 } __packed __aligned(8);
 759
 760 /*
 761  * bi_subvol and bi_parent_subvol are only set for subvolume roots:
 762  */
 763
 764 #define BCH_INODE_FIELDS_v2()                   \
 765         x(bi_atime,                     96)     \
 766         x(bi_ctime,                     96)     \
 767         x(bi_mtime,                     96)     \
 768         x(bi_otime,                     96)     \
 769         x(bi_size,                      64)     \
 770         x(bi_sectors,                   64)     \
 771         x(bi_uid,                       32)     \
 772         x(bi_gid,                       32)     \
 773         x(bi_nlink,                     32)     \
 774         x(bi_generation,                32)     \
 775         x(bi_dev,                       32)     \
 776         x(bi_data_checksum,             8)      \
 777         x(bi_compression,               8)      \
 778         x(bi_project,                   32)     \
 779         x(bi_background_compression,    8)      \
 780         x(bi_data_replicas,             8)      \
 781         x(bi_promote_target,            16)     \
 782         x(bi_foreground_target,         16)     \
 783         x(bi_background_target,         16)     \
 784         x(bi_erasure_code,              16)     \
 785         x(bi_fields_set,                16)     \
 786         x(bi_dir,                       64)     \
 787         x(bi_dir_offset,                64)     \
 788         x(bi_subvol,                    32)     \
 789         x(bi_parent_subvol,             32)
 790
 791 #define BCH_INODE_FIELDS_v3()                   \
 792         x(bi_atime,                     96)     \
 793         x(bi_ctime,                     96)     \
 794         x(bi_mtime,                     96)     \
 795         x(bi_otime,                     96)     \
 796         x(bi_uid,                       32)     \
 797         x(bi_gid,                       32)     \
 798         x(bi_nlink,                     32)     \
 799         x(bi_generation,                32)     \
 800         x(bi_dev,                       32)     \
 801         x(bi_data_checksum,             8)      \
 802         x(bi_compression,               8)      \
 803         x(bi_project,                   32)     \
 804         x(bi_background_compression,    8)      \
 805         x(bi_data_replicas,             8)      \
 806         x(bi_promote_target,            16)     \
 807         x(bi_foreground_target,         16)     \
 808         x(bi_background_target,         16)     \
 809         x(bi_erasure_code,              16)     \
 810         x(bi_fields_set,                16)     \
 811         x(bi_dir,                       64)     \
 812         x(bi_dir_offset,                64)     \
 813         x(bi_subvol,                    32)     \
 814         x(bi_parent_subvol,             32)     \
 815         x(bi_nocow,                     8)
 816
 817 /* subset of BCH_INODE_FIELDS */
 818 #define BCH_INODE_OPTS()                        \
 819         x(data_checksum,                8)      \
 820         x(compression,                  8)      \
 821         x(project,                      32)     \
 822         x(background_compression,       8)      \
 823         x(data_replicas,                8)      \
 824         x(promote_target,               16)     \
 825         x(foreground_target,            16)     \
 826         x(background_target,            16)     \
 827         x(erasure_code,                 16)     \
 828         x(nocow,                        8)
 829
 830 enum inode_opt_id {
 831 #define x(name, ...)                            \
 832         Inode_opt_##name,
 833         BCH_INODE_OPTS()
 834 #undef  x
 835         Inode_opt_nr,
 836 };
 837
 838 #define BCH_INODE_FLAGS()                       \
 839         x(sync,                         0)      \
 840         x(immutable,                    1)      \
 841         x(append,                       2)      \
 842         x(nodump,                       3)      \
 843         x(noatime,                      4)      \
 844         x(i_size_dirty,                 5)      \
 845         x(i_sectors_dirty,              6)      \
 846         x(unlinked,                     7)      \
 847         x(backptr_untrusted,            8)
 848
 849 /* bits 20+ reserved for packed fields below: */
 850
 851 enum bch_inode_flags {
 852 #define x(t, n) BCH_INODE_##t = 1U << n,
 853         BCH_INODE_FLAGS()
 854 #undef x
 855 };
 856
 857 enum __bch_inode_flags {
 858 #define x(t, n) __BCH_INODE_##t = n,
 859         BCH_INODE_FLAGS()
 860 #undef x
 861 };
 862
 863 LE32_BITMASK(INODE_STR_HASH,    struct bch_inode, bi_flags, 20, 24);
 864 LE32_BITMASK(INODE_NR_FIELDS,   struct bch_inode, bi_flags, 24, 31);
 865 LE32_BITMASK(INODE_NEW_VARINT,  struct bch_inode, bi_flags, 31, 32);
 866
 867 LE64_BITMASK(INODEv2_STR_HASH,  struct bch_inode_v2, bi_flags, 20, 24);
 868 LE64_BITMASK(INODEv2_NR_FIELDS, struct bch_inode_v2, bi_flags, 24, 31);
 869
 870 LE64_BITMASK(INODEv3_STR_HASH,  struct bch_inode_v3, bi_flags, 20, 24);
 871 LE64_BITMASK(INODEv3_NR_FIELDS, struct bch_inode_v3, bi_flags, 24, 31);
 872
 873 LE64_BITMASK(INODEv3_FIELDS_START,
 874                                 struct bch_inode_v3, bi_flags, 31, 36);
 875 LE64_BITMASK(INODEv3_MODE,      struct bch_inode_v3, bi_flags, 36, 52);
 876
 877 /* Dirents */
 878
 879 /*
 880  * Dirents (and xattrs) have to implement string lookups; since our b-tree
 881  * doesn't support arbitrary length strings for the key, we instead index by a
 882  * 64 bit hash (currently truncated sha1) of the string, stored in the offset
 883  * field of the key - using linear probing to resolve hash collisions. This also
 884  * provides us with the readdir cookie posix requires.
 885  *
 886  * Linear probing requires us to use whiteouts for deletions, in the event of a
 887  * collision:
 888  */
 889
 890 struct bch_dirent {
 891         struct bch_val          v;
 892
 893         /* Target inode number: */
 894         union {
 895         __le64                  d_inum;
 896         struct {                /* DT_SUBVOL */
 897         __le32                  d_child_subvol;
 898         __le32                  d_parent_subvol;
 899         };
 900         };
 901
 902         /*
 903          * Copy of mode bits 12-15 from the target inode - so userspace can get
 904          * the filetype without having to do a stat()
 905          */
 906         __u8                    d_type;
 907
 908         __u8                    d_name[];
 909 } __packed __aligned(8);
 910
 911 #define DT_SUBVOL       16
 912 #define BCH_DT_MAX      17
 913
 914 #define BCH_NAME_MAX    512
 915
 916 /* Xattrs */
 917
 918 #define KEY_TYPE_XATTR_INDEX_USER                       0
 919 #define KEY_TYPE_XATTR_INDEX_POSIX_ACL_ACCESS   1
 920 #define KEY_TYPE_XATTR_INDEX_POSIX_ACL_DEFAULT  2
 921 #define KEY_TYPE_XATTR_INDEX_TRUSTED                    3
 922 #define KEY_TYPE_XATTR_INDEX_SECURITY           4
 923
 924 struct bch_xattr {
 925         struct bch_val          v;
 926         __u8                    x_type;
 927         __u8                    x_name_len;
 928         __le16                  x_val_len;
 929         __u8                    x_name[];
 930 } __packed __aligned(8);
 931
 932 /* Bucket/allocation information: */
 933
 934 struct bch_alloc {
 935         struct bch_val          v;
 936         __u8                    fields;
 937         __u8                    gen;
 938         __u8                    data[];
 939 } __packed __aligned(8);
 940
 941 #define BCH_ALLOC_FIELDS_V1()                   \
 942         x(read_time,            16)             \
 943         x(write_time,           16)             \
 944         x(data_type,            8)              \
 945         x(dirty_sectors,        16)             \
 946         x(cached_sectors,       16)             \
 947         x(oldest_gen,           8)              \
 948         x(stripe,               32)             \
 949         x(stripe_redundancy,    8)
 950
 951 enum {
 952 #define x(name, _bits) BCH_ALLOC_FIELD_V1_##name,
 953         BCH_ALLOC_FIELDS_V1()
 954 #undef x
 955 };
 956
 957 struct bch_alloc_v2 {
 958         struct bch_val          v;
 959         __u8                    nr_fields;
 960         __u8                    gen;
 961         __u8                    oldest_gen;
 962         __u8                    data_type;
 963         __u8                    data[];
 964 } __packed __aligned(8);
 965
 966 #define BCH_ALLOC_FIELDS_V2()                   \
 967         x(read_time,            64)             \
 968         x(write_time,           64)             \
 969         x(dirty_sectors,        32)             \
 970         x(cached_sectors,       32)             \
 971         x(stripe,               32)             \
 972         x(stripe_redundancy,    8)
 973
 974 struct bch_alloc_v3 {
 975         struct bch_val          v;
 976         __le64                  journal_seq;
 977         __le32                  flags;
 978         __u8                    nr_fields;
 979         __u8                    gen;
 980         __u8                    oldest_gen;
 981         __u8                    data_type;
 982         __u8                    data[];
 983 } __packed __aligned(8);
 984
 985 LE32_BITMASK(BCH_ALLOC_V3_NEED_DISCARD,struct bch_alloc_v3, flags,  0,  1)
 986 LE32_BITMASK(BCH_ALLOC_V3_NEED_INC_GEN,struct bch_alloc_v3, flags,  1,  2)
 987
 988 struct bch_alloc_v4 {
 989         struct bch_val          v;
 990         __u64                   journal_seq;
 991         __u32                   flags;
 992         __u8                    gen;
 993         __u8                    oldest_gen;
 994         __u8                    data_type;
 995         __u8                    stripe_redundancy;
 996         __u32                   dirty_sectors;
 997         __u32                   cached_sectors;
 998         __u64                   io_time[2];
 999         __u32                   stripe;
1000         __u32                   nr_external_backpointers;
1001         __u64                   fragmentation_lru;
1002 } __packed __aligned(8);
1003
1004 #define BCH_ALLOC_V4_U64s_V0    6
1005 #define BCH_ALLOC_V4_U64s       (sizeof(struct bch_alloc_v4) / sizeof(__u64))
1006
1007 BITMASK(BCH_ALLOC_V4_NEED_DISCARD,      struct bch_alloc_v4, flags,  0,  1)
1008 BITMASK(BCH_ALLOC_V4_NEED_INC_GEN,      struct bch_alloc_v4, flags,  1,  2)
1009 BITMASK(BCH_ALLOC_V4_BACKPOINTERS_START,struct bch_alloc_v4, flags,  2,  8)
1010 BITMASK(BCH_ALLOC_V4_NR_BACKPOINTERS,   struct bch_alloc_v4, flags,  8,  14)
1011
1012 #define BCH_ALLOC_V4_NR_BACKPOINTERS_MAX        40
1013
1014 struct bch_backpointer {
1015         struct bch_val          v;
1016         __u8                    btree_id;
1017         __u8                    level;
1018         __u8                    data_type;
1019         __u64                   bucket_offset:40;
1020         __u32                   bucket_len;
1021         struct bpos             pos;
1022 } __packed __aligned(8);
1023
1024 #define KEY_TYPE_BUCKET_GENS_BITS       8
1025 #define KEY_TYPE_BUCKET_GENS_NR         (1U << KEY_TYPE_BUCKET_GENS_BITS)
1026 #define KEY_TYPE_BUCKET_GENS_MASK       (KEY_TYPE_BUCKET_GENS_NR - 1)
1027
1028 struct bch_bucket_gens {
1029         struct bch_val          v;
1030         u8                      gens[KEY_TYPE_BUCKET_GENS_NR];
1031 } __packed __aligned(8);
1032
1033 /* Quotas: */
1034
1035 enum quota_types {
1036         QTYP_USR                = 0,
1037         QTYP_GRP                = 1,
1038         QTYP_PRJ                = 2,
1039         QTYP_NR                 = 3,
1040 };
1041
1042 enum quota_counters {
1043         Q_SPC                   = 0,
1044         Q_INO                   = 1,
1045         Q_COUNTERS              = 2,
1046 };
1047
1048 struct bch_quota_counter {
1049         __le64                  hardlimit;
1050         __le64                  softlimit;
1051 };
1052
1053 struct bch_quota {
1054         struct bch_val          v;
1055         struct bch_quota_counter c[Q_COUNTERS];
1056 } __packed __aligned(8);
1057
1058 /* Erasure coding */
1059
1060 struct bch_stripe {
1061         struct bch_val          v;
1062         __le16                  sectors;
1063         __u8                    algorithm;
1064         __u8                    nr_blocks;
1065         __u8                    nr_redundant;
1066
1067         __u8                    csum_granularity_bits;
1068         __u8                    csum_type;
1069         __u8                    pad;
1070
1071         struct bch_extent_ptr   ptrs[];
1072 } __packed __aligned(8);
1073
1074 /* Reflink: */
1075
1076 struct bch_reflink_p {
1077         struct bch_val          v;
1078         __le64                  idx;
1079         /*
1080          * A reflink pointer might point to an indirect extent which is then
1081          * later split (by copygc or rebalance). If we only pointed to part of
1082          * the original indirect extent, and then one of the fragments is
1083          * outside the range we point to, we'd leak a refcount: so when creating
1084          * reflink pointers, we need to store pad values to remember the full
1085          * range we were taking a reference on.
1086          */
1087         __le32                  front_pad;
1088         __le32                  back_pad;
1089 } __packed __aligned(8);
1090
1091 struct bch_reflink_v {
1092         struct bch_val          v;
1093         __le64                  refcount;
1094         union bch_extent_entry  start[0];
1095         __u64                   _data[];
1096 } __packed __aligned(8);
1097
1098 struct bch_indirect_inline_data {
1099         struct bch_val          v;
1100         __le64                  refcount;
1101         u8                      data[];
1102 };
1103
1104 /* Inline data */
1105
1106 struct bch_inline_data {
1107         struct bch_val          v;
1108         u8                      data[];
1109 };
1110
1111 /* Subvolumes: */
1112
1113 #define SUBVOL_POS_MIN          POS(0, 1)
1114 #define SUBVOL_POS_MAX          POS(0, S32_MAX)
1115 #define BCACHEFS_ROOT_SUBVOL    1
1116
1117 struct bch_subvolume {
1118         struct bch_val          v;
1119         __le32                  flags;
1120         __le32                  snapshot;
1121         __le64                  inode;
1122         /*
1123          * Snapshot subvolumes form a tree, separate from the snapshot nodes
1124          * tree - if this subvolume is a snapshot, this is the ID of the
1125          * subvolume it was created from:
1126          *
1127          * This is _not_ necessarily the subvolume of the directory containing
1128          * this subvolume:
1129          */
1130         __le32                  parent;
1131         __le32                  pad;
1132         bch_le128               otime;
1133 };
1134
1135 LE32_BITMASK(BCH_SUBVOLUME_RO,          struct bch_subvolume, flags,  0,  1)
1136 /*
1137  * We need to know whether a subvolume is a snapshot so we can know whether we
1138  * can delete it (or whether it should just be rm -rf'd)
1139  */
1140 LE32_BITMASK(BCH_SUBVOLUME_SNAP,        struct bch_subvolume, flags,  1,  2)
1141 LE32_BITMASK(BCH_SUBVOLUME_UNLINKED,    struct bch_subvolume, flags,  2,  3)
1142
1143 /* Snapshots */
1144
1145 struct bch_snapshot {
1146         struct bch_val          v;
1147         __le32                  flags;
1148         __le32                  parent;
1149         __le32                  children[2];
1150         __le32                  subvol;
1151         /* corresponds to a bch_snapshot_tree in BTREE_ID_snapshot_trees */
1152         __le32                  tree;
1153         __le32                  depth;
1154         __le32                  skip[3];
1155         bch_le128               btime;
1156 };
1157
1158 LE32_BITMASK(BCH_SNAPSHOT_DELETED,      struct bch_snapshot, flags,  0,  1)
1159
1160 /* True if a subvolume points to this snapshot node: */
1161 LE32_BITMASK(BCH_SNAPSHOT_SUBVOL,       struct bch_snapshot, flags,  1,  2)
1162
1163 /*
1164  * Snapshot trees:
1165  *
1166  * The snapshot_trees btree gives us persistent indentifier for each tree of
1167  * bch_snapshot nodes, and allow us to record and easily find the root/master
1168  * subvolume that other snapshots were created from:
1169  */
1170 struct bch_snapshot_tree {
1171         struct bch_val          v;
1172         __le32                  master_subvol;
1173         __le32                  root_snapshot;
1174 };
1175
1176 /* LRU btree: */
1177
1178 struct bch_lru {
1179         struct bch_val          v;
1180         __le64                  idx;
1181 } __packed __aligned(8);
1182
1183 #define LRU_ID_STRIPES          (1U << 16)
1184
1185 /* Logged operations btree: */
1186
1187 struct bch_logged_op_truncate {
1188         struct bch_val          v;
1189         __le32                  subvol;
1190         __le32                  pad;
1191         __le64                  inum;
1192         __le64                  new_i_size;
1193 };
1194
1195 enum logged_op_finsert_state {
1196         LOGGED_OP_FINSERT_start,
1197         LOGGED_OP_FINSERT_shift_extents,
1198         LOGGED_OP_FINSERT_finish,
1199 };
1200
1201 struct bch_logged_op_finsert {
1202         struct bch_val          v;
1203         __u8                    state;
1204         __u8                    pad[3];
1205         __le32                  subvol;
1206         __le64                  inum;
1207         __le64                  dst_offset;
1208         __le64                  src_offset;
1209         __le64                  pos;
1210 };
1211
1212 /* Optional/variable size superblock sections: */
1213
1214 struct bch_sb_field {
1215         __u64                   _data[0];
1216         __le32                  u64s;
1217         __le32                  type;
1218 };
1219
1220 #define BCH_SB_FIELDS()                         \
1221         x(journal,                      0)      \
1222         x(members_v1,                   1)      \
1223         x(crypt,                        2)      \
1224         x(replicas_v0,                  3)      \
1225         x(quota,                        4)      \
1226         x(disk_groups,                  5)      \
1227         x(clean,                        6)      \
1228         x(replicas,                     7)      \
1229         x(journal_seq_blacklist,        8)      \
1230         x(journal_v2,                   9)      \
1231         x(counters,                     10)     \
1232         x(members_v2,                   11)     \
1233         x(errors,                       12)     \
1234         x(ext,                          13)     \
1235         x(downgrade,                    14)
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 #define BCH_MEMBER_ERROR_TYPES()                \
1286         x(read,         0)                      \
1287         x(write,        1)                      \
1288         x(checksum,     2)
1289
1290 enum bch_member_error_type {
1291 #define x(t, n) BCH_MEMBER_ERROR_##t = n,
1292         BCH_MEMBER_ERROR_TYPES()
1293 #undef x
1294         BCH_MEMBER_ERROR_NR
1295 };
1296
1297 struct bch_member {
1298         __uuid_t                uuid;
1299         __le64                  nbuckets;       /* device size */
1300         __le16                  first_bucket;   /* index of first bucket used */
1301         __le16                  bucket_size;    /* sectors */
1302         __le32                  pad;
1303         __le64                  last_mount;     /* time_t */
1304
1305         __le64                  flags;
1306         __le32                  iops[4];
1307         __le64                  errors[BCH_MEMBER_ERROR_NR];
1308         __le64                  errors_at_reset[BCH_MEMBER_ERROR_NR];
1309         __le64                  errors_reset_time;
1310         __le64                  seq;
1311 };
1312
1313 #define BCH_MEMBER_V1_BYTES     56
1314
1315 LE64_BITMASK(BCH_MEMBER_STATE,          struct bch_member, flags,  0,  4)
1316 /* 4-14 unused, was TIER, HAS_(META)DATA, REPLACEMENT */
1317 LE64_BITMASK(BCH_MEMBER_DISCARD,        struct bch_member, flags, 14, 15)
1318 LE64_BITMASK(BCH_MEMBER_DATA_ALLOWED,   struct bch_member, flags, 15, 20)
1319 LE64_BITMASK(BCH_MEMBER_GROUP,          struct bch_member, flags, 20, 28)
1320 LE64_BITMASK(BCH_MEMBER_DURABILITY,     struct bch_member, flags, 28, 30)
1321 LE64_BITMASK(BCH_MEMBER_FREESPACE_INITIALIZED,
1322                                         struct bch_member, flags, 30, 31)
1323
1324 #if 0
1325 LE64_BITMASK(BCH_MEMBER_NR_READ_ERRORS, struct bch_member, flags[1], 0,  20);
1326 LE64_BITMASK(BCH_MEMBER_NR_WRITE_ERRORS,struct bch_member, flags[1], 20, 40);
1327 #endif
1328
1329 #define BCH_MEMBER_STATES()                     \
1330         x(rw,           0)                      \
1331         x(ro,           1)                      \
1332         x(failed,       2)                      \
1333         x(spare,        3)
1334
1335 enum bch_member_state {
1336 #define x(t, n) BCH_MEMBER_STATE_##t = n,
1337         BCH_MEMBER_STATES()
1338 #undef x
1339         BCH_MEMBER_STATE_NR
1340 };
1341
1342 struct bch_sb_field_members_v1 {
1343         struct bch_sb_field     field;
1344         struct bch_member       _members[]; //Members are now variable size
1345 };
1346
1347 struct bch_sb_field_members_v2 {
1348         struct bch_sb_field     field;
1349         __le16                  member_bytes; //size of single member entry
1350         u8                      pad[6];
1351         struct bch_member       _members[];
1352 };
1353
1354 /* BCH_SB_FIELD_crypt: */
1355
1356 struct nonce {
1357         __le32                  d[4];
1358 };
1359
1360 struct bch_key {
1361         __le64                  key[4];
1362 };
1363
1364 #define BCH_KEY_MAGIC                                   \
1365         (((__u64) 'b' <<  0)|((__u64) 'c' <<  8)|               \
1366          ((__u64) 'h' << 16)|((__u64) '*' << 24)|               \
1367          ((__u64) '*' << 32)|((__u64) 'k' << 40)|               \
1368          ((__u64) 'e' << 48)|((__u64) 'y' << 56))
1369
1370 struct bch_encrypted_key {
1371         __le64                  magic;
1372         struct bch_key          key;
1373 };
1374
1375 /*
1376  * If this field is present in the superblock, it stores an encryption key which
1377  * is used encrypt all other data/metadata. The key will normally be encrypted
1378  * with the key userspace provides, but if encryption has been turned off we'll
1379  * just store the master key unencrypted in the superblock so we can access the
1380  * previously encrypted data.
1381  */
1382 struct bch_sb_field_crypt {
1383         struct bch_sb_field     field;
1384
1385         __le64                  flags;
1386         __le64                  kdf_flags;
1387         struct bch_encrypted_key key;
1388 };
1389
1390 LE64_BITMASK(BCH_CRYPT_KDF_TYPE,        struct bch_sb_field_crypt, flags, 0, 4);
1391
1392 enum bch_kdf_types {
1393         BCH_KDF_SCRYPT          = 0,
1394         BCH_KDF_NR              = 1,
1395 };
1396
1397 /* stored as base 2 log of scrypt params: */
1398 LE64_BITMASK(BCH_KDF_SCRYPT_N,  struct bch_sb_field_crypt, kdf_flags,  0, 16);
1399 LE64_BITMASK(BCH_KDF_SCRYPT_R,  struct bch_sb_field_crypt, kdf_flags, 16, 32);
1400 LE64_BITMASK(BCH_KDF_SCRYPT_P,  struct bch_sb_field_crypt, kdf_flags, 32, 48);
1401
1402 /* BCH_SB_FIELD_replicas: */
1403
1404 #define BCH_DATA_TYPES()                \
1405         x(free,         0)              \
1406         x(sb,           1)              \
1407         x(journal,      2)              \
1408         x(btree,        3)              \
1409         x(user,         4)              \
1410         x(cached,       5)              \
1411         x(parity,       6)              \
1412         x(stripe,       7)              \
1413         x(need_gc_gens, 8)              \
1414         x(need_discard, 9)
1415
1416 enum bch_data_type {
1417 #define x(t, n) BCH_DATA_##t,
1418         BCH_DATA_TYPES()
1419 #undef x
1420         BCH_DATA_NR
1421 };
1422
1423 static inline bool data_type_is_empty(enum bch_data_type type)
1424 {
1425         switch (type) {
1426         case BCH_DATA_free:
1427         case BCH_DATA_need_gc_gens:
1428         case BCH_DATA_need_discard:
1429                 return true;
1430         default:
1431                 return false;
1432         }
1433 }
1434
1435 static inline bool data_type_is_hidden(enum bch_data_type type)
1436 {
1437         switch (type) {
1438         case BCH_DATA_sb:
1439         case BCH_DATA_journal:
1440                 return true;
1441         default:
1442                 return false;
1443         }
1444 }
1445
1446 struct bch_replicas_entry_v0 {
1447         __u8                    data_type;
1448         __u8                    nr_devs;
1449         __u8                    devs[];
1450 } __packed;
1451
1452 struct bch_sb_field_replicas_v0 {
1453         struct bch_sb_field     field;
1454         struct bch_replicas_entry_v0 entries[];
1455 } __packed __aligned(8);
1456
1457 struct bch_replicas_entry_v1 {
1458         __u8                    data_type;
1459         __u8                    nr_devs;
1460         __u8                    nr_required;
1461         __u8                    devs[];
1462 } __packed;
1463
1464 #define replicas_entry_bytes(_i)                                        \
1465         (offsetof(typeof(*(_i)), devs) + (_i)->nr_devs)
1466
1467 struct bch_sb_field_replicas {
1468         struct bch_sb_field     field;
1469         struct bch_replicas_entry_v1 entries[];
1470 } __packed __aligned(8);
1471
1472 /* BCH_SB_FIELD_quota: */
1473
1474 struct bch_sb_quota_counter {
1475         __le32                          timelimit;
1476         __le32                          warnlimit;
1477 };
1478
1479 struct bch_sb_quota_type {
1480         __le64                          flags;
1481         struct bch_sb_quota_counter     c[Q_COUNTERS];
1482 };
1483
1484 struct bch_sb_field_quota {
1485         struct bch_sb_field             field;
1486         struct bch_sb_quota_type        q[QTYP_NR];
1487 } __packed __aligned(8);
1488
1489 /* BCH_SB_FIELD_disk_groups: */
1490
1491 #define BCH_SB_LABEL_SIZE               32
1492
1493 struct bch_disk_group {
1494         __u8                    label[BCH_SB_LABEL_SIZE];
1495         __le64                  flags[2];
1496 } __packed __aligned(8);
1497
1498 LE64_BITMASK(BCH_GROUP_DELETED,         struct bch_disk_group, flags[0], 0,  1)
1499 LE64_BITMASK(BCH_GROUP_DATA_ALLOWED,    struct bch_disk_group, flags[0], 1,  6)
1500 LE64_BITMASK(BCH_GROUP_PARENT,          struct bch_disk_group, flags[0], 6, 24)
1501
1502 struct bch_sb_field_disk_groups {
1503         struct bch_sb_field     field;
1504         struct bch_disk_group   entries[];
1505 } __packed __aligned(8);
1506
1507 /* BCH_SB_FIELD_counters */
1508
1509 #define BCH_PERSISTENT_COUNTERS()                               \
1510         x(io_read,                                      0)      \
1511         x(io_write,                                     1)      \
1512         x(io_move,                                      2)      \
1513         x(bucket_invalidate,                            3)      \
1514         x(bucket_discard,                               4)      \
1515         x(bucket_alloc,                                 5)      \
1516         x(bucket_alloc_fail,                            6)      \
1517         x(btree_cache_scan,                             7)      \
1518         x(btree_cache_reap,                             8)      \
1519         x(btree_cache_cannibalize,                      9)      \
1520         x(btree_cache_cannibalize_lock,                 10)     \
1521         x(btree_cache_cannibalize_lock_fail,            11)     \
1522         x(btree_cache_cannibalize_unlock,               12)     \
1523         x(btree_node_write,                             13)     \
1524         x(btree_node_read,                              14)     \
1525         x(btree_node_compact,                           15)     \
1526         x(btree_node_merge,                             16)     \
1527         x(btree_node_split,                             17)     \
1528         x(btree_node_rewrite,                           18)     \
1529         x(btree_node_alloc,                             19)     \
1530         x(btree_node_free,                              20)     \
1531         x(btree_node_set_root,                          21)     \
1532         x(btree_path_relock_fail,                       22)     \
1533         x(btree_path_upgrade_fail,                      23)     \
1534         x(btree_reserve_get_fail,                       24)     \
1535         x(journal_entry_full,                           25)     \
1536         x(journal_full,                                 26)     \
1537         x(journal_reclaim_finish,                       27)     \
1538         x(journal_reclaim_start,                        28)     \
1539         x(journal_write,                                29)     \
1540         x(read_promote,                                 30)     \
1541         x(read_bounce,                                  31)     \
1542         x(read_split,                                   33)     \
1543         x(read_retry,                                   32)     \
1544         x(read_reuse_race,                              34)     \
1545         x(move_extent_read,                             35)     \
1546         x(move_extent_write,                            36)     \
1547         x(move_extent_finish,                           37)     \
1548         x(move_extent_fail,                             38)     \
1549         x(move_extent_start_fail,                       39)     \
1550         x(copygc,                                       40)     \
1551         x(copygc_wait,                                  41)     \
1552         x(gc_gens_end,                                  42)     \
1553         x(gc_gens_start,                                43)     \
1554         x(trans_blocked_journal_reclaim,                44)     \
1555         x(trans_restart_btree_node_reused,              45)     \
1556         x(trans_restart_btree_node_split,               46)     \
1557         x(trans_restart_fault_inject,                   47)     \
1558         x(trans_restart_iter_upgrade,                   48)     \
1559         x(trans_restart_journal_preres_get,             49)     \
1560         x(trans_restart_journal_reclaim,                50)     \
1561         x(trans_restart_journal_res_get,                51)     \
1562         x(trans_restart_key_cache_key_realloced,        52)     \
1563         x(trans_restart_key_cache_raced,                53)     \
1564         x(trans_restart_mark_replicas,                  54)     \
1565         x(trans_restart_mem_realloced,                  55)     \
1566         x(trans_restart_memory_allocation_failure,      56)     \
1567         x(trans_restart_relock,                         57)     \
1568         x(trans_restart_relock_after_fill,              58)     \
1569         x(trans_restart_relock_key_cache_fill,          59)     \
1570         x(trans_restart_relock_next_node,               60)     \
1571         x(trans_restart_relock_parent_for_fill,         61)     \
1572         x(trans_restart_relock_path,                    62)     \
1573         x(trans_restart_relock_path_intent,             63)     \
1574         x(trans_restart_too_many_iters,                 64)     \
1575         x(trans_restart_traverse,                       65)     \
1576         x(trans_restart_upgrade,                        66)     \
1577         x(trans_restart_would_deadlock,                 67)     \
1578         x(trans_restart_would_deadlock_write,           68)     \
1579         x(trans_restart_injected,                       69)     \
1580         x(trans_restart_key_cache_upgrade,              70)     \
1581         x(trans_traverse_all,                           71)     \
1582         x(transaction_commit,                           72)     \
1583         x(write_super,                                  73)     \
1584         x(trans_restart_would_deadlock_recursion_limit, 74)     \
1585         x(trans_restart_write_buffer_flush,             75)     \
1586         x(trans_restart_split_race,                     76)     \
1587         x(write_buffer_flush_slowpath,                  77)     \
1588         x(write_buffer_flush_sync,                      78)
1589
1590 enum bch_persistent_counters {
1591 #define x(t, n, ...) BCH_COUNTER_##t,
1592         BCH_PERSISTENT_COUNTERS()
1593 #undef x
1594         BCH_COUNTER_NR
1595 };
1596
1597 struct bch_sb_field_counters {
1598         struct bch_sb_field     field;
1599         __le64                  d[];
1600 };
1601
1602 /*
1603  * On clean shutdown, store btree roots and current journal sequence number in
1604  * the superblock:
1605  */
1606 struct jset_entry {
1607         __le16                  u64s;
1608         __u8                    btree_id;
1609         __u8                    level;
1610         __u8                    type; /* designates what this jset holds */
1611         __u8                    pad[3];
1612
1613         struct bkey_i           start[0];
1614         __u64                   _data[];
1615 };
1616
1617 struct bch_sb_field_clean {
1618         struct bch_sb_field     field;
1619
1620         __le32                  flags;
1621         __le16                  _read_clock; /* no longer used */
1622         __le16                  _write_clock;
1623         __le64                  journal_seq;
1624
1625         struct jset_entry       start[0];
1626         __u64                   _data[];
1627 };
1628
1629 struct journal_seq_blacklist_entry {
1630         __le64                  start;
1631         __le64                  end;
1632 };
1633
1634 struct bch_sb_field_journal_seq_blacklist {
1635         struct bch_sb_field     field;
1636         struct journal_seq_blacklist_entry start[];
1637 };
1638
1639 struct bch_sb_field_errors {
1640         struct bch_sb_field     field;
1641         struct bch_sb_field_error_entry {
1642                 __le64          v;
1643                 __le64          last_error_time;
1644         }                       entries[];
1645 };
1646
1647 LE64_BITMASK(BCH_SB_ERROR_ENTRY_ID,     struct bch_sb_field_error_entry, v,  0, 16);
1648 LE64_BITMASK(BCH_SB_ERROR_ENTRY_NR,     struct bch_sb_field_error_entry, v, 16, 64);
1649
1650 struct bch_sb_field_ext {
1651         struct bch_sb_field     field;
1652         __le64                  recovery_passes_required[2];
1653         __le64                  errors_silent[8];
1654 };
1655
1656 struct bch_sb_field_downgrade_entry {
1657         __le16                  version;
1658         __le64                  recovery_passes[2];
1659         __le16                  nr_errors;
1660         __le16                  errors[] __counted_by(nr_errors);
1661 } __packed __aligned(2);
1662
1663 struct bch_sb_field_downgrade {
1664         struct bch_sb_field     field;
1665         struct bch_sb_field_downgrade_entry entries[];
1666 };
1667
1668 /* Superblock: */
1669
1670 /*
1671  * New versioning scheme:
1672  * One common version number for all on disk data structures - superblock, btree
1673  * nodes, journal entries
1674  */
1675 #define BCH_VERSION_MAJOR(_v)           ((__u16) ((_v) >> 10))
1676 #define BCH_VERSION_MINOR(_v)           ((__u16) ((_v) & ~(~0U << 10)))
1677 #define BCH_VERSION(_major, _minor)     (((_major) << 10)|(_minor) << 0)
1678
1679 /*
1680  * field 1:             version name
1681  * field 2:             BCH_VERSION(major, minor)
1682  * field 3:             recovery passess required on upgrade
1683  */
1684 #define BCH_METADATA_VERSIONS()                                         \
1685         x(bkey_renumber,                BCH_VERSION(0, 10))             \
1686         x(inode_btree_change,           BCH_VERSION(0, 11))             \
1687         x(snapshot,                     BCH_VERSION(0, 12))             \
1688         x(inode_backpointers,           BCH_VERSION(0, 13))             \
1689         x(btree_ptr_sectors_written,    BCH_VERSION(0, 14))             \
1690         x(snapshot_2,                   BCH_VERSION(0, 15))             \
1691         x(reflink_p_fix,                BCH_VERSION(0, 16))             \
1692         x(subvol_dirent,                BCH_VERSION(0, 17))             \
1693         x(inode_v2,                     BCH_VERSION(0, 18))             \
1694         x(freespace,                    BCH_VERSION(0, 19))             \
1695         x(alloc_v4,                     BCH_VERSION(0, 20))             \
1696         x(new_data_types,               BCH_VERSION(0, 21))             \
1697         x(backpointers,                 BCH_VERSION(0, 22))             \
1698         x(inode_v3,                     BCH_VERSION(0, 23))             \
1699         x(unwritten_extents,            BCH_VERSION(0, 24))             \
1700         x(bucket_gens,                  BCH_VERSION(0, 25))             \
1701         x(lru_v2,                       BCH_VERSION(0, 26))             \
1702         x(fragmentation_lru,            BCH_VERSION(0, 27))             \
1703         x(no_bps_in_alloc_keys,         BCH_VERSION(0, 28))             \
1704         x(snapshot_trees,               BCH_VERSION(0, 29))             \
1705         x(major_minor,                  BCH_VERSION(1,  0))             \
1706         x(snapshot_skiplists,           BCH_VERSION(1,  1))             \
1707         x(deleted_inodes,               BCH_VERSION(1,  2))             \
1708         x(rebalance_work,               BCH_VERSION(1,  3))             \
1709         x(member_seq,                   BCH_VERSION(1,  4))
1710
1711 enum bcachefs_metadata_version {
1712         bcachefs_metadata_version_min = 9,
1713 #define x(t, n) bcachefs_metadata_version_##t = n,
1714         BCH_METADATA_VERSIONS()
1715 #undef x
1716         bcachefs_metadata_version_max
1717 };
1718
1719 static const __maybe_unused
1720 unsigned bcachefs_metadata_required_upgrade_below = bcachefs_metadata_version_rebalance_work;
1721
1722 #define bcachefs_metadata_version_current       (bcachefs_metadata_version_max - 1)
1723
1724 #define BCH_SB_SECTOR                   8
1725 #define BCH_SB_MEMBERS_MAX              64 /* XXX kill */
1726
1727 struct bch_sb_layout {
1728         __uuid_t                magic;  /* bcachefs superblock UUID */
1729         __u8                    layout_type;
1730         __u8                    sb_max_size_bits; /* base 2 of 512 byte sectors */
1731         __u8                    nr_superblocks;
1732         __u8                    pad[5];
1733         __le64                  sb_offset[61];
1734 } __packed __aligned(8);
1735
1736 #define BCH_SB_LAYOUT_SECTOR    7
1737
1738 /*
1739  * @offset      - sector where this sb was written
1740  * @version     - on disk format version
1741  * @version_min - Oldest metadata version this filesystem contains; so we can
1742  *                safely drop compatibility code and refuse to mount filesystems
1743  *                we'd need it for
1744  * @magic       - identifies as a bcachefs superblock (BCHFS_MAGIC)
1745  * @seq         - incremented each time superblock is written
1746  * @uuid        - used for generating various magic numbers and identifying
1747  *                member devices, never changes
1748  * @user_uuid   - user visible UUID, may be changed
1749  * @label       - filesystem label
1750  * @seq         - identifies most recent superblock, incremented each time
1751  *                superblock is written
1752  * @features    - enabled incompatible features
1753  */
1754 struct bch_sb {
1755         struct bch_csum         csum;
1756         __le16                  version;
1757         __le16                  version_min;
1758         __le16                  pad[2];
1759         __uuid_t                magic;
1760         __uuid_t                uuid;
1761         __uuid_t                user_uuid;
1762         __u8                    label[BCH_SB_LABEL_SIZE];
1763         __le64                  offset;
1764         __le64                  seq;
1765
1766         __le16                  block_size;
1767         __u8                    dev_idx;
1768         __u8                    nr_devices;
1769         __le32                  u64s;
1770
1771         __le64                  time_base_lo;
1772         __le32                  time_base_hi;
1773         __le32                  time_precision;
1774
1775         __le64                  flags[7];
1776         __le64                  write_time;
1777         __le64                  features[2];
1778         __le64                  compat[2];
1779
1780         struct bch_sb_layout    layout;
1781
1782         struct bch_sb_field     start[0];
1783         __le64                  _data[];
1784 } __packed __aligned(8);
1785
1786 /*
1787  * Flags:
1788  * BCH_SB_INITALIZED    - set on first mount
1789  * BCH_SB_CLEAN         - did we shut down cleanly? Just a hint, doesn't affect
1790  *                        behaviour of mount/recovery path:
1791  * BCH_SB_INODE_32BIT   - limit inode numbers to 32 bits
1792  * BCH_SB_128_BIT_MACS  - 128 bit macs instead of 80
1793  * BCH_SB_ENCRYPTION_TYPE - if nonzero encryption is enabled; overrides
1794  *                         DATA/META_CSUM_TYPE. Also indicates encryption
1795  *                         algorithm in use, if/when we get more than one
1796  */
1797
1798 LE16_BITMASK(BCH_SB_BLOCK_SIZE,         struct bch_sb, block_size, 0, 16);
1799
1800 LE64_BITMASK(BCH_SB_INITIALIZED,        struct bch_sb, flags[0],  0,  1);
1801 LE64_BITMASK(BCH_SB_CLEAN,              struct bch_sb, flags[0],  1,  2);
1802 LE64_BITMASK(BCH_SB_CSUM_TYPE,          struct bch_sb, flags[0],  2,  8);
1803 LE64_BITMASK(BCH_SB_ERROR_ACTION,       struct bch_sb, flags[0],  8, 12);
1804
1805 LE64_BITMASK(BCH_SB_BTREE_NODE_SIZE,    struct bch_sb, flags[0], 12, 28);
1806
1807 LE64_BITMASK(BCH_SB_GC_RESERVE,         struct bch_sb, flags[0], 28, 33);
1808 LE64_BITMASK(BCH_SB_ROOT_RESERVE,       struct bch_sb, flags[0], 33, 40);
1809
1810 LE64_BITMASK(BCH_SB_META_CSUM_TYPE,     struct bch_sb, flags[0], 40, 44);
1811 LE64_BITMASK(BCH_SB_DATA_CSUM_TYPE,     struct bch_sb, flags[0], 44, 48);
1812
1813 LE64_BITMASK(BCH_SB_META_REPLICAS_WANT, struct bch_sb, flags[0], 48, 52);
1814 LE64_BITMASK(BCH_SB_DATA_REPLICAS_WANT, struct bch_sb, flags[0], 52, 56);
1815
1816 LE64_BITMASK(BCH_SB_POSIX_ACL,          struct bch_sb, flags[0], 56, 57);
1817 LE64_BITMASK(BCH_SB_USRQUOTA,           struct bch_sb, flags[0], 57, 58);
1818 LE64_BITMASK(BCH_SB_GRPQUOTA,           struct bch_sb, flags[0], 58, 59);
1819 LE64_BITMASK(BCH_SB_PRJQUOTA,           struct bch_sb, flags[0], 59, 60);
1820
1821 LE64_BITMASK(BCH_SB_HAS_ERRORS,         struct bch_sb, flags[0], 60, 61);
1822 LE64_BITMASK(BCH_SB_HAS_TOPOLOGY_ERRORS,struct bch_sb, flags[0], 61, 62);
1823
1824 LE64_BITMASK(BCH_SB_BIG_ENDIAN,         struct bch_sb, flags[0], 62, 63);
1825
1826 LE64_BITMASK(BCH_SB_STR_HASH_TYPE,      struct bch_sb, flags[1],  0,  4);
1827 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_LO,struct bch_sb, flags[1],  4,  8);
1828 LE64_BITMASK(BCH_SB_INODE_32BIT,        struct bch_sb, flags[1],  8,  9);
1829
1830 LE64_BITMASK(BCH_SB_128_BIT_MACS,       struct bch_sb, flags[1],  9, 10);
1831 LE64_BITMASK(BCH_SB_ENCRYPTION_TYPE,    struct bch_sb, flags[1], 10, 14);
1832
1833 /*
1834  * Max size of an extent that may require bouncing to read or write
1835  * (checksummed, compressed): 64k
1836  */
1837 LE64_BITMASK(BCH_SB_ENCODED_EXTENT_MAX_BITS,
1838                                         struct bch_sb, flags[1], 14, 20);
1839
1840 LE64_BITMASK(BCH_SB_META_REPLICAS_REQ,  struct bch_sb, flags[1], 20, 24);
1841 LE64_BITMASK(BCH_SB_DATA_REPLICAS_REQ,  struct bch_sb, flags[1], 24, 28);
1842
1843 LE64_BITMASK(BCH_SB_PROMOTE_TARGET,     struct bch_sb, flags[1], 28, 40);
1844 LE64_BITMASK(BCH_SB_FOREGROUND_TARGET,  struct bch_sb, flags[1], 40, 52);
1845 LE64_BITMASK(BCH_SB_BACKGROUND_TARGET,  struct bch_sb, flags[1], 52, 64);
1846
1847 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO,
1848                                         struct bch_sb, flags[2],  0,  4);
1849 LE64_BITMASK(BCH_SB_GC_RESERVE_BYTES,   struct bch_sb, flags[2],  4, 64);
1850
1851 LE64_BITMASK(BCH_SB_ERASURE_CODE,       struct bch_sb, flags[3],  0, 16);
1852 LE64_BITMASK(BCH_SB_METADATA_TARGET,    struct bch_sb, flags[3], 16, 28);
1853 LE64_BITMASK(BCH_SB_SHARD_INUMS,        struct bch_sb, flags[3], 28, 29);
1854 LE64_BITMASK(BCH_SB_INODES_USE_KEY_CACHE,struct bch_sb, flags[3], 29, 30);
1855 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DELAY,struct bch_sb, flags[3], 30, 62);
1856 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DISABLED,struct bch_sb, flags[3], 62, 63);
1857 LE64_BITMASK(BCH_SB_JOURNAL_RECLAIM_DELAY,struct bch_sb, flags[4], 0, 32);
1858 LE64_BITMASK(BCH_SB_JOURNAL_TRANSACTION_NAMES,struct bch_sb, flags[4], 32, 33);
1859 LE64_BITMASK(BCH_SB_NOCOW,              struct bch_sb, flags[4], 33, 34);
1860 LE64_BITMASK(BCH_SB_WRITE_BUFFER_SIZE,  struct bch_sb, flags[4], 34, 54);
1861 LE64_BITMASK(BCH_SB_VERSION_UPGRADE,    struct bch_sb, flags[4], 54, 56);
1862
1863 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_HI,struct bch_sb, flags[4], 56, 60);
1864 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI,
1865                                         struct bch_sb, flags[4], 60, 64);
1866
1867 LE64_BITMASK(BCH_SB_VERSION_UPGRADE_COMPLETE,
1868                                         struct bch_sb, flags[5],  0, 16);
1869
1870 static inline __u64 BCH_SB_COMPRESSION_TYPE(const struct bch_sb *sb)
1871 {
1872         return BCH_SB_COMPRESSION_TYPE_LO(sb) | (BCH_SB_COMPRESSION_TYPE_HI(sb) << 4);
1873 }
1874
1875 static inline void SET_BCH_SB_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1876 {
1877         SET_BCH_SB_COMPRESSION_TYPE_LO(sb, v);
1878         SET_BCH_SB_COMPRESSION_TYPE_HI(sb, v >> 4);
1879 }
1880
1881 static inline __u64 BCH_SB_BACKGROUND_COMPRESSION_TYPE(const struct bch_sb *sb)
1882 {
1883         return BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb) |
1884                 (BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb) << 4);
1885 }
1886
1887 static inline void SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1888 {
1889         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb, v);
1890         SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb, v >> 4);
1891 }
1892
1893 /*
1894  * Features:
1895  *
1896  * journal_seq_blacklist_v3:    gates BCH_SB_FIELD_journal_seq_blacklist
1897  * reflink:                     gates KEY_TYPE_reflink
1898  * inline_data:                 gates KEY_TYPE_inline_data
1899  * new_siphash:                 gates BCH_STR_HASH_siphash
1900  * new_extent_overwrite:        gates BTREE_NODE_NEW_EXTENT_OVERWRITE
1901  */
1902 #define BCH_SB_FEATURES()                       \
1903         x(lz4,                          0)      \
1904         x(gzip,                         1)      \
1905         x(zstd,                         2)      \
1906         x(atomic_nlink,                 3)      \
1907         x(ec,                           4)      \
1908         x(journal_seq_blacklist_v3,     5)      \
1909         x(reflink,                      6)      \
1910         x(new_siphash,                  7)      \
1911         x(inline_data,                  8)      \
1912         x(new_extent_overwrite,         9)      \
1913         x(incompressible,               10)     \
1914         x(btree_ptr_v2,                 11)     \
1915         x(extents_above_btree_updates,  12)     \
1916         x(btree_updates_journalled,     13)     \
1917         x(reflink_inline_data,          14)     \
1918         x(new_varint,                   15)     \
1919         x(journal_no_flush,             16)     \
1920         x(alloc_v2,                     17)     \
1921         x(extents_across_btree_nodes,   18)
1922
1923 #define BCH_SB_FEATURES_ALWAYS                          \
1924         ((1ULL << BCH_FEATURE_new_extent_overwrite)|    \
1925          (1ULL << BCH_FEATURE_extents_above_btree_updates)|\
1926          (1ULL << BCH_FEATURE_btree_updates_journalled)|\
1927          (1ULL << BCH_FEATURE_alloc_v2)|\
1928          (1ULL << BCH_FEATURE_extents_across_btree_nodes))
1929
1930 #define BCH_SB_FEATURES_ALL                             \
1931         (BCH_SB_FEATURES_ALWAYS|                        \
1932          (1ULL << BCH_FEATURE_new_siphash)|             \
1933          (1ULL << BCH_FEATURE_btree_ptr_v2)|            \
1934          (1ULL << BCH_FEATURE_new_varint)|              \
1935          (1ULL << BCH_FEATURE_journal_no_flush))
1936
1937 enum bch_sb_feature {
1938 #define x(f, n) BCH_FEATURE_##f,
1939         BCH_SB_FEATURES()
1940 #undef x
1941         BCH_FEATURE_NR,
1942 };
1943
1944 #define BCH_SB_COMPAT()                                 \
1945         x(alloc_info,                           0)      \
1946         x(alloc_metadata,                       1)      \
1947         x(extents_above_btree_updates_done,     2)      \
1948         x(bformat_overflow_done,                3)
1949
1950 enum bch_sb_compat {
1951 #define x(f, n) BCH_COMPAT_##f,
1952         BCH_SB_COMPAT()
1953 #undef x
1954         BCH_COMPAT_NR,
1955 };
1956
1957 /* options: */
1958
1959 #define BCH_VERSION_UPGRADE_OPTS()      \
1960         x(compatible,           0)      \
1961         x(incompatible,         1)      \
1962         x(none,                 2)
1963
1964 enum bch_version_upgrade_opts {
1965 #define x(t, n) BCH_VERSION_UPGRADE_##t = n,
1966         BCH_VERSION_UPGRADE_OPTS()
1967 #undef x
1968 };
1969
1970 #define BCH_REPLICAS_MAX                4U
1971
1972 #define BCH_BKEY_PTRS_MAX               16U
1973
1974 #define BCH_ERROR_ACTIONS()             \
1975         x(continue,             0)      \
1976         x(ro,                   1)      \
1977         x(panic,                2)
1978
1979 enum bch_error_actions {
1980 #define x(t, n) BCH_ON_ERROR_##t = n,
1981         BCH_ERROR_ACTIONS()
1982 #undef x
1983         BCH_ON_ERROR_NR
1984 };
1985
1986 #define BCH_STR_HASH_TYPES()            \
1987         x(crc32c,               0)      \
1988         x(crc64,                1)      \
1989         x(siphash_old,          2)      \
1990         x(siphash,              3)
1991
1992 enum bch_str_hash_type {
1993 #define x(t, n) BCH_STR_HASH_##t = n,
1994         BCH_STR_HASH_TYPES()
1995 #undef x
1996         BCH_STR_HASH_NR
1997 };
1998
1999 #define BCH_STR_HASH_OPTS()             \
2000         x(crc32c,               0)      \
2001         x(crc64,                1)      \
2002         x(siphash,              2)
2003
2004 enum bch_str_hash_opts {
2005 #define x(t, n) BCH_STR_HASH_OPT_##t = n,
2006         BCH_STR_HASH_OPTS()
2007 #undef x
2008         BCH_STR_HASH_OPT_NR
2009 };
2010
2011 #define BCH_CSUM_TYPES()                        \
2012         x(none,                         0)      \
2013         x(crc32c_nonzero,               1)      \
2014         x(crc64_nonzero,                2)      \
2015         x(chacha20_poly1305_80,         3)      \
2016         x(chacha20_poly1305_128,        4)      \
2017         x(crc32c,                       5)      \
2018         x(crc64,                        6)      \
2019         x(xxhash,                       7)
2020
2021 enum bch_csum_type {
2022 #define x(t, n) BCH_CSUM_##t = n,
2023         BCH_CSUM_TYPES()
2024 #undef x
2025         BCH_CSUM_NR
2026 };
2027
2028 static const __maybe_unused unsigned bch_crc_bytes[] = {
2029         [BCH_CSUM_none]                         = 0,
2030         [BCH_CSUM_crc32c_nonzero]               = 4,
2031         [BCH_CSUM_crc32c]                       = 4,
2032         [BCH_CSUM_crc64_nonzero]                = 8,
2033         [BCH_CSUM_crc64]                        = 8,
2034         [BCH_CSUM_xxhash]                       = 8,
2035         [BCH_CSUM_chacha20_poly1305_80]         = 10,
2036         [BCH_CSUM_chacha20_poly1305_128]        = 16,
2037 };
2038
2039 static inline _Bool bch2_csum_type_is_encryption(enum bch_csum_type type)
2040 {
2041         switch (type) {
2042         case BCH_CSUM_chacha20_poly1305_80:
2043         case BCH_CSUM_chacha20_poly1305_128:
2044                 return true;
2045         default:
2046                 return false;
2047         }
2048 }
2049
2050 #define BCH_CSUM_OPTS()                 \
2051         x(none,                 0)      \
2052         x(crc32c,               1)      \
2053         x(crc64,                2)      \
2054         x(xxhash,               3)
2055
2056 enum bch_csum_opts {
2057 #define x(t, n) BCH_CSUM_OPT_##t = n,
2058         BCH_CSUM_OPTS()
2059 #undef x
2060         BCH_CSUM_OPT_NR
2061 };
2062
2063 #define BCH_COMPRESSION_TYPES()         \
2064         x(none,                 0)      \
2065         x(lz4_old,              1)      \
2066         x(gzip,                 2)      \
2067         x(lz4,                  3)      \
2068         x(zstd,                 4)      \
2069         x(incompressible,       5)
2070
2071 enum bch_compression_type {
2072 #define x(t, n) BCH_COMPRESSION_TYPE_##t = n,
2073         BCH_COMPRESSION_TYPES()
2074 #undef x
2075         BCH_COMPRESSION_TYPE_NR
2076 };
2077
2078 #define BCH_COMPRESSION_OPTS()          \
2079         x(none,         0)              \
2080         x(lz4,          1)              \
2081         x(gzip,         2)              \
2082         x(zstd,         3)
2083
2084 enum bch_compression_opts {
2085 #define x(t, n) BCH_COMPRESSION_OPT_##t = n,
2086         BCH_COMPRESSION_OPTS()
2087 #undef x
2088         BCH_COMPRESSION_OPT_NR
2089 };
2090
2091 /*
2092  * Magic numbers
2093  *
2094  * The various other data structures have their own magic numbers, which are
2095  * xored with the first part of the cache set's UUID
2096  */
2097
2098 #define BCACHE_MAGIC                                                    \
2099         UUID_INIT(0xc68573f6, 0x4e1a, 0x45ca,                           \
2100                   0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81)
2101 #define BCHFS_MAGIC                                                     \
2102         UUID_INIT(0xc68573f6, 0x66ce, 0x90a9,                           \
2103                   0xd9, 0x6a, 0x60, 0xcf, 0x80, 0x3d, 0xf7, 0xef)
2104
2105 #define BCACHEFS_STATFS_MAGIC           0xca451a4e
2106
2107 #define JSET_MAGIC              __cpu_to_le64(0x245235c1a3625032ULL)
2108 #define BSET_MAGIC              __cpu_to_le64(0x90135c78b99e07f5ULL)
2109
2110 static inline __le64 __bch2_sb_magic(struct bch_sb *sb)
2111 {
2112         __le64 ret;
2113
2114         memcpy(&ret, &sb->uuid, sizeof(ret));
2115         return ret;
2116 }
2117
2118 static inline __u64 __jset_magic(struct bch_sb *sb)
2119 {
2120         return __le64_to_cpu(__bch2_sb_magic(sb) ^ JSET_MAGIC);
2121 }
2122
2123 static inline __u64 __bset_magic(struct bch_sb *sb)
2124 {
2125         return __le64_to_cpu(__bch2_sb_magic(sb) ^ BSET_MAGIC);
2126 }
2127
2128 /* Journal */
2129
2130 #define JSET_KEYS_U64s  (sizeof(struct jset_entry) / sizeof(__u64))
2131
2132 #define BCH_JSET_ENTRY_TYPES()                  \
2133         x(btree_keys,           0)              \
2134         x(btree_root,           1)              \
2135         x(prio_ptrs,            2)              \
2136         x(blacklist,            3)              \
2137         x(blacklist_v2,         4)              \
2138         x(usage,                5)              \
2139         x(data_usage,           6)              \
2140         x(clock,                7)              \
2141         x(dev_usage,            8)              \
2142         x(log,                  9)              \
2143         x(overwrite,            10)             \
2144         x(write_buffer_keys,    11)
2145
2146 enum {
2147 #define x(f, nr)        BCH_JSET_ENTRY_##f      = nr,
2148         BCH_JSET_ENTRY_TYPES()
2149 #undef x
2150         BCH_JSET_ENTRY_NR
2151 };
2152
2153 static inline bool jset_entry_is_key(struct jset_entry *e)
2154 {
2155         switch (e->type) {
2156         case BCH_JSET_ENTRY_btree_keys:
2157         case BCH_JSET_ENTRY_btree_root:
2158         case BCH_JSET_ENTRY_overwrite:
2159         case BCH_JSET_ENTRY_write_buffer_keys:
2160                 return true;
2161         }
2162
2163         return false;
2164 }
2165
2166 /*
2167  * Journal sequence numbers can be blacklisted: bsets record the max sequence
2168  * number of all the journal entries they contain updates for, so that on
2169  * recovery we can ignore those bsets that contain index updates newer that what
2170  * made it into the journal.
2171  *
2172  * This means that we can't reuse that journal_seq - we have to skip it, and
2173  * then record that we skipped it so that the next time we crash and recover we
2174  * don't think there was a missing journal entry.
2175  */
2176 struct jset_entry_blacklist {
2177         struct jset_entry       entry;
2178         __le64                  seq;
2179 };
2180
2181 struct jset_entry_blacklist_v2 {
2182         struct jset_entry       entry;
2183         __le64                  start;
2184         __le64                  end;
2185 };
2186
2187 #define BCH_FS_USAGE_TYPES()                    \
2188         x(reserved,             0)              \
2189         x(inodes,               1)              \
2190         x(key_version,          2)
2191
2192 enum {
2193 #define x(f, nr)        BCH_FS_USAGE_##f        = nr,
2194         BCH_FS_USAGE_TYPES()
2195 #undef x
2196         BCH_FS_USAGE_NR
2197 };
2198
2199 struct jset_entry_usage {
2200         struct jset_entry       entry;
2201         __le64                  v;
2202 } __packed;
2203
2204 struct jset_entry_data_usage {
2205         struct jset_entry       entry;
2206         __le64                  v;
2207         struct bch_replicas_entry_v1 r;
2208 } __packed;
2209
2210 struct jset_entry_clock {
2211         struct jset_entry       entry;
2212         __u8                    rw;
2213         __u8                    pad[7];
2214         __le64                  time;
2215 } __packed;
2216
2217 struct jset_entry_dev_usage_type {
2218         __le64                  buckets;
2219         __le64                  sectors;
2220         __le64                  fragmented;
2221 } __packed;
2222
2223 struct jset_entry_dev_usage {
2224         struct jset_entry       entry;
2225         __le32                  dev;
2226         __u32                   pad;
2227
2228         __le64                  _buckets_ec;            /* No longer used */
2229         __le64                  _buckets_unavailable;   /* No longer used */
2230
2231         struct jset_entry_dev_usage_type d[];
2232 };
2233
2234 static inline unsigned jset_entry_dev_usage_nr_types(struct jset_entry_dev_usage *u)
2235 {
2236         return (vstruct_bytes(&u->entry) - sizeof(struct jset_entry_dev_usage)) /
2237                 sizeof(struct jset_entry_dev_usage_type);
2238 }
2239
2240 struct jset_entry_log {
2241         struct jset_entry       entry;
2242         u8                      d[];
2243 } __packed __aligned(8);
2244
2245 /*
2246  * On disk format for a journal entry:
2247  * seq is monotonically increasing; every journal entry has its own unique
2248  * sequence number.
2249  *
2250  * last_seq is the oldest journal entry that still has keys the btree hasn't
2251  * flushed to disk yet.
2252  *
2253  * version is for on disk format changes.
2254  */
2255 struct jset {
2256         struct bch_csum         csum;
2257
2258         __le64                  magic;
2259         __le64                  seq;
2260         __le32                  version;
2261         __le32                  flags;
2262
2263         __le32                  u64s; /* size of d[] in u64s */
2264
2265         __u8                    encrypted_start[0];
2266
2267         __le16                  _read_clock; /* no longer used */
2268         __le16                  _write_clock;
2269
2270         /* Sequence number of oldest dirty journal entry */
2271         __le64                  last_seq;
2272
2273
2274         struct jset_entry       start[0];
2275         __u64                   _data[];
2276 } __packed __aligned(8);
2277
2278 LE32_BITMASK(JSET_CSUM_TYPE,    struct jset, flags, 0, 4);
2279 LE32_BITMASK(JSET_BIG_ENDIAN,   struct jset, flags, 4, 5);
2280 LE32_BITMASK(JSET_NO_FLUSH,     struct jset, flags, 5, 6);
2281
2282 #define BCH_JOURNAL_BUCKETS_MIN         8
2283
2284 /* Btree: */
2285
2286 enum btree_id_flags {
2287         BTREE_ID_EXTENTS        = BIT(0),
2288         BTREE_ID_SNAPSHOTS      = BIT(1),
2289         BTREE_ID_SNAPSHOT_FIELD = BIT(2),
2290         BTREE_ID_DATA           = BIT(3),
2291 };
2292
2293 #define BCH_BTREE_IDS()                                                         \
2294         x(extents,              0,      BTREE_ID_EXTENTS|BTREE_ID_SNAPSHOTS|BTREE_ID_DATA,\
2295           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2296           BIT_ULL(KEY_TYPE_error)|                                              \
2297           BIT_ULL(KEY_TYPE_cookie)|                                             \
2298           BIT_ULL(KEY_TYPE_extent)|                                             \
2299           BIT_ULL(KEY_TYPE_reservation)|                                        \
2300           BIT_ULL(KEY_TYPE_reflink_p)|                                          \
2301           BIT_ULL(KEY_TYPE_inline_data))                                        \
2302         x(inodes,               1,      BTREE_ID_SNAPSHOTS,                     \
2303           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2304           BIT_ULL(KEY_TYPE_inode)|                                              \
2305           BIT_ULL(KEY_TYPE_inode_v2)|                                           \
2306           BIT_ULL(KEY_TYPE_inode_v3)|                                           \
2307           BIT_ULL(KEY_TYPE_inode_generation))                                   \
2308         x(dirents,              2,      BTREE_ID_SNAPSHOTS,                     \
2309           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2310           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
2311           BIT_ULL(KEY_TYPE_dirent))                                             \
2312         x(xattrs,               3,      BTREE_ID_SNAPSHOTS,                     \
2313           BIT_ULL(KEY_TYPE_whiteout)|                                           \
2314           BIT_ULL(KEY_TYPE_cookie)|                                             \
2315           BIT_ULL(KEY_TYPE_hash_whiteout)|                                      \
2316           BIT_ULL(KEY_TYPE_xattr))                                              \
2317         x(alloc,                4,      0,                                      \
2318           BIT_ULL(KEY_TYPE_alloc)|                                              \
2319           BIT_ULL(KEY_TYPE_alloc_v2)|                                           \
2320           BIT_ULL(KEY_TYPE_alloc_v3)|                                           \
2321           BIT_ULL(KEY_TYPE_alloc_v4))                                           \
2322         x(quotas,               5,      0,                                      \
2323           BIT_ULL(KEY_TYPE_quota))                                              \
2324         x(stripes,              6,      0,                                      \
2325           BIT_ULL(KEY_TYPE_stripe))                                             \
2326         x(reflink,              7,      BTREE_ID_EXTENTS|BTREE_ID_DATA,         \
2327           BIT_ULL(KEY_TYPE_reflink_v)|                                          \
2328           BIT_ULL(KEY_TYPE_indirect_inline_data))                               \
2329         x(subvolumes,           8,      0,                                      \
2330           BIT_ULL(KEY_TYPE_subvolume))                                          \
2331         x(snapshots,            9,      0,                                      \
2332           BIT_ULL(KEY_TYPE_snapshot))                                           \
2333         x(lru,                  10,     0,                                      \
2334           BIT_ULL(KEY_TYPE_set))                                                \
2335         x(freespace,            11,     BTREE_ID_EXTENTS,                       \
2336           BIT_ULL(KEY_TYPE_set))                                                \
2337         x(need_discard,         12,     0,                                      \
2338           BIT_ULL(KEY_TYPE_set))                                                \
2339         x(backpointers,         13,     0,                                      \
2340           BIT_ULL(KEY_TYPE_backpointer))                                        \
2341         x(bucket_gens,          14,     0,                                      \
2342           BIT_ULL(KEY_TYPE_bucket_gens))                                        \
2343         x(snapshot_trees,       15,     0,                                      \
2344           BIT_ULL(KEY_TYPE_snapshot_tree))                                      \
2345         x(deleted_inodes,       16,     BTREE_ID_SNAPSHOT_FIELD,                \
2346           BIT_ULL(KEY_TYPE_set))                                                \
2347         x(logged_ops,           17,     0,                                      \
2348           BIT_ULL(KEY_TYPE_logged_op_truncate)|                                 \
2349           BIT_ULL(KEY_TYPE_logged_op_finsert))                                  \
2350         x(rebalance_work,       18,     BTREE_ID_SNAPSHOT_FIELD,                \
2351           BIT_ULL(KEY_TYPE_set)|BIT_ULL(KEY_TYPE_cookie))
2352
2353 enum btree_id {
2354 #define x(name, nr, ...) BTREE_ID_##name = nr,
2355         BCH_BTREE_IDS()
2356 #undef x
2357         BTREE_ID_NR
2358 };
2359
2360 #define BTREE_MAX_DEPTH         4U
2361
2362 /* Btree nodes */
2363
2364 /*
2365  * Btree nodes
2366  *
2367  * On disk a btree node is a list/log of these; within each set the keys are
2368  * sorted
2369  */
2370 struct bset {
2371         __le64                  seq;
2372
2373         /*
2374          * Highest journal entry this bset contains keys for.
2375          * If on recovery we don't see that journal entry, this bset is ignored:
2376          * this allows us to preserve the order of all index updates after a
2377          * crash, since the journal records a total order of all index updates
2378          * and anything that didn't make it to the journal doesn't get used.
2379          */
2380         __le64                  journal_seq;
2381
2382         __le32                  flags;
2383         __le16                  version;
2384         __le16                  u64s; /* count of d[] in u64s */
2385
2386         struct bkey_packed      start[0];
2387         __u64                   _data[];
2388 } __packed __aligned(8);
2389
2390 LE32_BITMASK(BSET_CSUM_TYPE,    struct bset, flags, 0, 4);
2391
2392 LE32_BITMASK(BSET_BIG_ENDIAN,   struct bset, flags, 4, 5);
2393 LE32_BITMASK(BSET_SEPARATE_WHITEOUTS,
2394                                 struct bset, flags, 5, 6);
2395
2396 /* Sector offset within the btree node: */
2397 LE32_BITMASK(BSET_OFFSET,       struct bset, flags, 16, 32);
2398
2399 struct btree_node {
2400         struct bch_csum         csum;
2401         __le64                  magic;
2402
2403         /* this flags field is encrypted, unlike bset->flags: */
2404         __le64                  flags;
2405
2406         /* Closed interval: */
2407         struct bpos             min_key;
2408         struct bpos             max_key;
2409         struct bch_extent_ptr   _ptr; /* not used anymore */
2410         struct bkey_format      format;
2411
2412         union {
2413         struct bset             keys;
2414         struct {
2415                 __u8            pad[22];
2416                 __le16          u64s;
2417                 __u64           _data[0];
2418
2419         };
2420         };
2421 } __packed __aligned(8);
2422
2423 LE64_BITMASK(BTREE_NODE_ID_LO,  struct btree_node, flags,  0,  4);
2424 LE64_BITMASK(BTREE_NODE_LEVEL,  struct btree_node, flags,  4,  8);
2425 LE64_BITMASK(BTREE_NODE_NEW_EXTENT_OVERWRITE,
2426                                 struct btree_node, flags,  8,  9);
2427 LE64_BITMASK(BTREE_NODE_ID_HI,  struct btree_node, flags,  9, 25);
2428 /* 25-32 unused */
2429 LE64_BITMASK(BTREE_NODE_SEQ,    struct btree_node, flags, 32, 64);
2430
2431 static inline __u64 BTREE_NODE_ID(struct btree_node *n)
2432 {
2433         return BTREE_NODE_ID_LO(n) | (BTREE_NODE_ID_HI(n) << 4);
2434 }
2435
2436 static inline void SET_BTREE_NODE_ID(struct btree_node *n, __u64 v)
2437 {
2438         SET_BTREE_NODE_ID_LO(n, v);
2439         SET_BTREE_NODE_ID_HI(n, v >> 4);
2440 }
2441
2442 struct btree_node_entry {
2443         struct bch_csum         csum;
2444
2445         union {
2446         struct bset             keys;
2447         struct {
2448                 __u8            pad[22];
2449                 __le16          u64s;
2450                 __u64           _data[0];
2451         };
2452         };
2453 } __packed __aligned(8);
2454
2455 #endif /* _BCACHEFS_FORMAT_H */