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Diffstat (limited to 'fs/bcachefs/bcachefs_format.h')
| -rw-r--r-- | fs/bcachefs/bcachefs_format.h | 2425 |
1 files changed, 2425 insertions, 0 deletions
diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h new file mode 100644 index 000000000000..0a750953ff92 --- /dev/null +++ b/fs/bcachefs/bcachefs_format.h @@ -0,0 +1,2425 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _BCACHEFS_FORMAT_H +#define _BCACHEFS_FORMAT_H + +/* + * bcachefs on disk data structures + * + * OVERVIEW: + * + * There are three main types of on disk data structures in bcachefs (this is + * reduced from 5 in bcache) + * + * - superblock + * - journal + * - btree + * + * The btree is the primary structure; most metadata exists as keys in the + * various btrees. There are only a small number of btrees, they're not + * sharded - we have one btree for extents, another for inodes, et cetera. + * + * SUPERBLOCK: + * + * The superblock contains the location of the journal, the list of devices in + * the filesystem, and in general any metadata we need in order to decide + * whether we can start a filesystem or prior to reading the journal/btree + * roots. + * + * The superblock is extensible, and most of the contents of the superblock are + * in variable length, type tagged fields; see struct bch_sb_field. + * + * Backup superblocks do not reside in a fixed location; also, superblocks do + * not have a fixed size. To locate backup superblocks we have struct + * bch_sb_layout; we store a copy of this inside every superblock, and also + * before the first superblock. + * + * JOURNAL: + * + * The journal primarily records btree updates in the order they occurred; + * journal replay consists of just iterating over all the keys in the open + * journal entries and re-inserting them into the btrees. + * + * The journal also contains entry types for the btree roots, and blacklisted + * journal sequence numbers (see journal_seq_blacklist.c). + * + * BTREE: + * + * bcachefs btrees are copy on write b+ trees, where nodes are big (typically + * 128k-256k) and log structured. We use struct btree_node for writing the first + * entry in a given node (offset 0), and struct btree_node_entry for all + * subsequent writes. + * + * After the header, btree node entries contain a list of keys in sorted order. + * Values are stored inline with the keys; since values are variable length (and + * keys effectively are variable length too, due to packing) we can't do random + * access without building up additional in memory tables in the btree node read + * path. + * + * BTREE KEYS (struct bkey): + * + * The various btrees share a common format for the key - so as to avoid + * switching in fastpath lookup/comparison code - but define their own + * structures for the key values. + * + * The size of a key/value pair is stored as a u8 in units of u64s, so the max + * size is just under 2k. The common part also contains a type tag for the + * value, and a format field indicating whether the key is packed or not (and + * also meant to allow adding new key fields in the future, if desired). + * + * bkeys, when stored within a btree node, may also be packed. In that case, the + * bkey_format in that node is used to unpack it. Packed bkeys mean that we can + * be generous with field sizes in the common part of the key format (64 bit + * inode number, 64 bit offset, 96 bit version field, etc.) for negligible cost. + */ + +#include <asm/types.h> +#include <asm/byteorder.h> +#include <linux/kernel.h> +#include <linux/uuid.h> +#include "vstructs.h" + +#ifdef __KERNEL__ +typedef uuid_t __uuid_t; +#endif + +#define BITMASK(name, type, field, offset, end) \ +static const __maybe_unused unsigned name##_OFFSET = offset; \ +static const __maybe_unused unsigned name##_BITS = (end - offset); \ + \ +static inline __u64 name(const type *k) \ +{ \ + return (k->field >> offset) & ~(~0ULL << (end - offset)); \ +} \ + \ +static inline void SET_##name(type *k, __u64 v) \ +{ \ + k->field &= ~(~(~0ULL << (end - offset)) << offset); \ + k->field |= (v & ~(~0ULL << (end - offset))) << offset; \ +} + +#define LE_BITMASK(_bits, name, type, field, offset, end) \ +static const __maybe_unused unsigned name##_OFFSET = offset; \ +static const __maybe_unused unsigned name##_BITS = (end - offset); \ +static const __maybe_unused __u##_bits name##_MAX = (1ULL << (end - offset)) - 1;\ + \ +static inline __u64 name(const type *k) \ +{ \ + return (__le##_bits##_to_cpu(k->field) >> offset) & \ + ~(~0ULL << (end - offset)); \ +} \ + \ +static inline void SET_##name(type *k, __u64 v) \ +{ \ + __u##_bits new = __le##_bits##_to_cpu(k->field); \ + \ + new &= ~(~(~0ULL << (end - offset)) << offset); \ + new |= (v & ~(~0ULL << (end - offset))) << offset; \ + k->field = __cpu_to_le##_bits(new); \ +} + +#define LE16_BITMASK(n, t, f, o, e) LE_BITMASK(16, n, t, f, o, e) +#define LE32_BITMASK(n, t, f, o, e) LE_BITMASK(32, n, t, f, o, e) +#define LE64_BITMASK(n, t, f, o, e) LE_BITMASK(64, n, t, f, o, e) + +struct bkey_format { + __u8 key_u64s; + __u8 nr_fields; + /* One unused slot for now: */ + __u8 bits_per_field[6]; + __le64 field_offset[6]; +}; + +/* Btree keys - all units are in sectors */ + +struct bpos { + /* + * Word order matches machine byte order - btree code treats a bpos as a + * single large integer, for search/comparison purposes + * + * Note that wherever a bpos is embedded in another on disk data + * structure, it has to be byte swabbed when reading in metadata that + * wasn't written in native endian order: + */ +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + __u32 snapshot; + __u64 offset; + __u64 inode; +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + __u64 inode; + __u64 offset; /* Points to end of extent - sectors */ + __u32 snapshot; +#else +#error edit for your odd byteorder. +#endif +} __packed __aligned(4); + +#define KEY_INODE_MAX ((__u64)~0ULL) +#define KEY_OFFSET_MAX ((__u64)~0ULL) +#define KEY_SNAPSHOT_MAX ((__u32)~0U) +#define KEY_SIZE_MAX ((__u32)~0U) + +static inline struct bpos SPOS(__u64 inode, __u64 offset, __u32 snapshot) +{ + return (struct bpos) { + .inode = inode, + .offset = offset, + .snapshot = snapshot, + }; +} + +#define POS_MIN SPOS(0, 0, 0) +#define POS_MAX SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, 0) +#define SPOS_MAX SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, KEY_SNAPSHOT_MAX) +#define POS(_inode, _offset) SPOS(_inode, _offset, 0) + +/* Empty placeholder struct, for container_of() */ +struct bch_val { + __u64 __nothing[0]; +}; + +struct bversion { +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + __u64 lo; + __u32 hi; +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + __u32 hi; + __u64 lo; +#endif +} __packed __aligned(4); + +struct bkey { + /* Size of combined key and value, in u64s */ + __u8 u64s; + + /* Format of key (0 for format local to btree node) */ +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u8 format:7, + needs_whiteout:1; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u8 needs_whiteout:1, + format:7; +#else +#error edit for your odd byteorder. +#endif + + /* Type of the value */ + __u8 type; + +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + __u8 pad[1]; + + struct bversion version; + __u32 size; /* extent size, in sectors */ + struct bpos p; +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + struct bpos p; + __u32 size; /* extent size, in sectors */ + struct bversion version; + + __u8 pad[1]; +#endif +} __packed __aligned(8); + +struct bkey_packed { + __u64 _data[0]; + + /* Size of combined key and value, in u64s */ + __u8 u64s; + + /* Format of key (0 for format local to btree node) */ + + /* + * XXX: next incompat on disk format change, switch format and + * needs_whiteout - bkey_packed() will be cheaper if format is the high + * bits of the bitfield + */ +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u8 format:7, + needs_whiteout:1; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u8 needs_whiteout:1, + format:7; +#endif + + /* Type of the value */ + __u8 type; + __u8 key_start[0]; + + /* + * We copy bkeys with struct assignment in various places, and while + * that shouldn't be done with packed bkeys we can't disallow it in C, + * and it's legal to cast a bkey to a bkey_packed - so padding it out + * to the same size as struct bkey should hopefully be safest. + */ + __u8 pad[sizeof(struct bkey) - 3]; +} __packed __aligned(8); + +typedef struct { + __le64 lo; + __le64 hi; +} bch_le128; + +#define BKEY_U64s (sizeof(struct bkey) / sizeof(__u64)) +#define BKEY_U64s_MAX U8_MAX +#define BKEY_VAL_U64s_MAX (BKEY_U64s_MAX - BKEY_U64s) + +#define KEY_PACKED_BITS_START 24 + +#define KEY_FORMAT_LOCAL_BTREE 0 +#define KEY_FORMAT_CURRENT 1 + +enum bch_bkey_fields { + BKEY_FIELD_INODE, + BKEY_FIELD_OFFSET, + BKEY_FIELD_SNAPSHOT, + BKEY_FIELD_SIZE, + BKEY_FIELD_VERSION_HI, + BKEY_FIELD_VERSION_LO, + BKEY_NR_FIELDS, +}; + +#define bkey_format_field(name, field) \ + [BKEY_FIELD_##name] = (sizeof(((struct bkey *) NULL)->field) * 8) + +#define BKEY_FORMAT_CURRENT \ +((struct bkey_format) { \ + .key_u64s = BKEY_U64s, \ + .nr_fields = BKEY_NR_FIELDS, \ + .bits_per_field = { \ + bkey_format_field(INODE, p.inode), \ + bkey_format_field(OFFSET, p.offset), \ + bkey_format_field(SNAPSHOT, p.snapshot), \ + bkey_format_field(SIZE, size), \ + bkey_format_field(VERSION_HI, version.hi), \ + bkey_format_field(VERSION_LO, version.lo), \ + }, \ +}) + +/* bkey with inline value */ +struct bkey_i { + __u64 _data[0]; + + struct bkey k; + struct bch_val v; +}; + +#define KEY(_inode, _offset, _size) \ +((struct bkey) { \ + .u64s = BKEY_U64s, \ + .format = KEY_FORMAT_CURRENT, \ + .p = POS(_inode, _offset), \ + .size = _size, \ +}) + +static inline void bkey_init(struct bkey *k) +{ + *k = KEY(0, 0, 0); +} + +#define bkey_bytes(_k) ((_k)->u64s * sizeof(__u64)) + +#define __BKEY_PADDED(key, pad) \ + struct bkey_i key; __u64 key ## _pad[pad] + +/* + * - DELETED keys are used internally to mark keys that should be ignored but + * override keys in composition order. Their version number is ignored. + * + * - DISCARDED keys indicate that the data is all 0s because it has been + * discarded. DISCARDs may have a version; if the version is nonzero the key + * will be persistent, otherwise the key will be dropped whenever the btree + * node is rewritten (like DELETED keys). + * + * - ERROR: any read of the data returns a read error, as the data was lost due + * to a failing device. Like DISCARDED keys, they can be removed (overridden) + * by new writes or cluster-wide GC. Node repair can also overwrite them with + * the same or a more recent version number, but not with an older version + * number. + * + * - WHITEOUT: for hash table btrees + */ +#define BCH_BKEY_TYPES() \ + x(deleted, 0) \ + x(whiteout, 1) \ + x(error, 2) \ + x(cookie, 3) \ + x(hash_whiteout, 4) \ + x(btree_ptr, 5) \ + x(extent, 6) \ + x(reservation, 7) \ + x(inode, 8) \ + x(inode_generation, 9) \ + x(dirent, 10) \ + x(xattr, 11) \ + x(alloc, 12) \ + x(quota, 13) \ + x(stripe, 14) \ + x(reflink_p, 15) \ + x(reflink_v, 16) \ + x(inline_data, 17) \ + x(btree_ptr_v2, 18) \ + x(indirect_inline_data, 19) \ + x(alloc_v2, 20) \ + x(subvolume, 21) \ + x(snapshot, 22) \ + x(inode_v2, 23) \ + x(alloc_v3, 24) \ + x(set, 25) \ + x(lru, 26) \ + x(alloc_v4, 27) \ + x(backpointer, 28) \ + x(inode_v3, 29) \ + x(bucket_gens, 30) \ + x(snapshot_tree, 31) \ + x(logged_op_truncate, 32) \ + x(logged_op_finsert, 33) + +enum bch_bkey_type { +#define x(name, nr) KEY_TYPE_##name = nr, + BCH_BKEY_TYPES() +#undef x + KEY_TYPE_MAX, +}; + +struct bch_deleted { + struct bch_val v; +}; + +struct bch_whiteout { + struct bch_val v; +}; + +struct bch_error { + struct bch_val v; +}; + +struct bch_cookie { + struct bch_val v; + __le64 cookie; +}; + +struct bch_hash_whiteout { + struct bch_val v; +}; + +struct bch_set { + struct bch_val v; +}; + +/* Extents */ + +/* + * In extent bkeys, the value is a list of pointers (bch_extent_ptr), optionally + * preceded by checksum/compression information (bch_extent_crc32 or + * bch_extent_crc64). + * + * One major determining factor in the format of extents is how we handle and + * represent extents that have been partially overwritten and thus trimmed: + * + * If an extent is not checksummed or compressed, when the extent is trimmed we + * don't have to remember the extent we originally allocated and wrote: we can + * merely adjust ptr->offset to point to the start of the data that is currently + * live. The size field in struct bkey records the current (live) size of the + * extent, and is also used to mean "size of region on disk that we point to" in + * this case. + * + * Thus an extent that is not checksummed or compressed will consist only of a + * list of bch_extent_ptrs, with none of the fields in + * bch_extent_crc32/bch_extent_crc64. + * + * When an extent is checksummed or compressed, it's not possible to read only + * the data that is currently live: we have to read the entire extent that was + * originally written, and then return only the part of the extent that is + * currently live. + * + * Thus, in addition to the current size of the extent in struct bkey, we need + * to store the size of the originally allocated space - this is the + * compressed_size and uncompressed_size fields in bch_extent_crc32/64. Also, + * when the extent is trimmed, instead of modifying the offset field of the + * pointer, we keep a second smaller offset field - "offset into the original + * extent of the currently live region". + * + * The other major determining factor is replication and data migration: + * + * Each pointer may have its own bch_extent_crc32/64. When doing a replicated + * write, we will initially write all the replicas in the same format, with the + * same checksum type and compression format - however, when copygc runs later (or + * tiering/cache promotion, anything that moves data), it is not in general + * going to rewrite all the pointers at once - one of the replicas may be in a + * bucket on one device that has very little fragmentation while another lives + * in a bucket that has become heavily fragmented, and thus is being rewritten + * sooner than the rest. + * + * Thus it will only move a subset of the pointers (or in the case of + * tiering/cache promotion perhaps add a single pointer without dropping any + * current pointers), and if the extent has been partially overwritten it must + * write only the currently live portion (or copygc would not be able to reduce + * fragmentation!) - which necessitates a different bch_extent_crc format for + * the new pointer. + * + * But in the interests of space efficiency, we don't want to store one + * bch_extent_crc for each pointer if we don't have to. + * + * Thus, a bch_extent consists of bch_extent_crc32s, bch_extent_crc64s, and + * bch_extent_ptrs appended arbitrarily one after the other. We determine the + * type of a given entry with a scheme similar to utf8 (except we're encoding a + * type, not a size), encoding the type in the position of the first set bit: + * + * bch_extent_crc32 - 0b1 + * bch_extent_ptr - 0b10 + * bch_extent_crc64 - 0b100 + * + * We do it this way because bch_extent_crc32 is _very_ constrained on bits (and + * bch_extent_crc64 is the least constrained). + * + * Then, each bch_extent_crc32/64 applies to the pointers that follow after it, + * until the next bch_extent_crc32/64. + * + * If there are no bch_extent_crcs preceding a bch_extent_ptr, then that pointer + * is neither checksummed nor compressed. + */ + +/* 128 bits, sufficient for cryptographic MACs: */ +struct bch_csum { + __le64 lo; + __le64 hi; +} __packed __aligned(8); + +#define BCH_EXTENT_ENTRY_TYPES() \ + x(ptr, 0) \ + x(crc32, 1) \ + x(crc64, 2) \ + x(crc128, 3) \ + x(stripe_ptr, 4) \ + x(rebalance, 5) +#define BCH_EXTENT_ENTRY_MAX 6 + +enum bch_extent_entry_type { +#define x(f, n) BCH_EXTENT_ENTRY_##f = n, + BCH_EXTENT_ENTRY_TYPES() +#undef x +}; + +/* Compressed/uncompressed size are stored biased by 1: */ +struct bch_extent_crc32 { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u32 type:2, + _compressed_size:7, + _uncompressed_size:7, + offset:7, + _unused:1, + csum_type:4, + compression_type:4; + __u32 csum; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u32 csum; + __u32 compression_type:4, + csum_type:4, + _unused:1, + offset:7, + _uncompressed_size:7, + _compressed_size:7, + type:2; +#endif +} __packed __aligned(8); + +#define CRC32_SIZE_MAX (1U << 7) +#define CRC32_NONCE_MAX 0 + +struct bch_extent_crc64 { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u64 type:3, + _compressed_size:9, + _uncompressed_size:9, + offset:9, + nonce:10, + csum_type:4, + compression_type:4, + csum_hi:16; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u64 csum_hi:16, + compression_type:4, + csum_type:4, + nonce:10, + offset:9, + _uncompressed_size:9, + _compressed_size:9, + type:3; +#endif + __u64 csum_lo; +} __packed __aligned(8); + +#define CRC64_SIZE_MAX (1U << 9) +#define CRC64_NONCE_MAX ((1U << 10) - 1) + +struct bch_extent_crc128 { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u64 type:4, + _compressed_size:13, + _uncompressed_size:13, + offset:13, + nonce:13, + csum_type:4, + compression_type:4; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u64 compression_type:4, + csum_type:4, + nonce:13, + offset:13, + _uncompressed_size:13, + _compressed_size:13, + type:4; +#endif + struct bch_csum csum; +} __packed __aligned(8); + +#define CRC128_SIZE_MAX (1U << 13) +#define CRC128_NONCE_MAX ((1U << 13) - 1) + +/* + * @reservation - pointer hasn't been written to, just reserved + */ +struct bch_extent_ptr { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u64 type:1, + cached:1, + unused:1, + unwritten:1, + offset:44, /* 8 petabytes */ + dev:8, + gen:8; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u64 gen:8, + dev:8, + offset:44, + unwritten:1, + unused:1, + cached:1, + type:1; +#endif +} __packed __aligned(8); + +struct bch_extent_stripe_ptr { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u64 type:5, + block:8, + redundancy:4, + idx:47; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u64 idx:47, + redundancy:4, + block:8, + type:5; +#endif +}; + +struct bch_extent_rebalance { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u64 type:6, + unused:34, + compression:8, /* enum bch_compression_opt */ + target:16; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u64 target:16, + compression:8, + unused:34, + type:6; +#endif +}; + +union bch_extent_entry { +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ || __BITS_PER_LONG == 64 + unsigned long type; +#elif __BITS_PER_LONG == 32 + struct { + unsigned long pad; + unsigned long type; + }; +#else +#error edit for your odd byteorder. +#endif + +#define x(f, n) struct bch_extent_##f f; + BCH_EXTENT_ENTRY_TYPES() +#undef x +}; + +struct bch_btree_ptr { + struct bch_val v; + + __u64 _data[0]; + struct bch_extent_ptr start[]; +} __packed __aligned(8); + +struct bch_btree_ptr_v2 { + struct bch_val v; + + __u64 mem_ptr; + __le64 seq; + __le16 sectors_written; + __le16 flags; + struct bpos min_key; + __u64 _data[0]; + struct bch_extent_ptr start[]; +} __packed __aligned(8); + +LE16_BITMASK(BTREE_PTR_RANGE_UPDATED, struct bch_btree_ptr_v2, flags, 0, 1); + +struct bch_extent { + struct bch_val v; + + __u64 _data[0]; + union bch_extent_entry start[]; +} __packed __aligned(8); + +struct bch_reservation { + struct bch_val v; + + __le32 generation; + __u8 nr_replicas; + __u8 pad[3]; +} __packed __aligned(8); + +/* Maximum size (in u64s) a single pointer could be: */ +#define BKEY_EXTENT_PTR_U64s_MAX\ + ((sizeof(struct bch_extent_crc128) + \ + sizeof(struct bch_extent_ptr)) / sizeof(__u64)) + +/* Maximum possible size of an entire extent value: */ +#define BKEY_EXTENT_VAL_U64s_MAX \ + (1 + BKEY_EXTENT_PTR_U64s_MAX * (BCH_REPLICAS_MAX + 1)) + +/* * Maximum possible size of an entire extent, key + value: */ +#define BKEY_EXTENT_U64s_MAX (BKEY_U64s + BKEY_EXTENT_VAL_U64s_MAX) + +/* Btree pointers don't carry around checksums: */ +#define BKEY_BTREE_PTR_VAL_U64s_MAX \ + ((sizeof(struct bch_btree_ptr_v2) + \ + sizeof(struct bch_extent_ptr) * BCH_REPLICAS_MAX) / sizeof(__u64)) +#define BKEY_BTREE_PTR_U64s_MAX \ + (BKEY_U64s + BKEY_BTREE_PTR_VAL_U64s_MAX) + +/* Inodes */ + +#define BLOCKDEV_INODE_MAX 4096 + +#define BCACHEFS_ROOT_INO 4096 + +struct bch_inode { + struct bch_val v; + + __le64 bi_hash_seed; + __le32 bi_flags; + __le16 bi_mode; + __u8 fields[]; +} __packed __aligned(8); + +struct bch_inode_v2 { + struct bch_val v; + + __le64 bi_journal_seq; + __le64 bi_hash_seed; + __le64 bi_flags; + __le16 bi_mode; + __u8 fields[]; +} __packed __aligned(8); + +struct bch_inode_v3 { + struct bch_val v; + + __le64 bi_journal_seq; + __le64 bi_hash_seed; + __le64 bi_flags; + __le64 bi_sectors; + __le64 bi_size; + __le64 bi_version; + __u8 fields[]; +} __packed __aligned(8); + +#define INODEv3_FIELDS_START_INITIAL 6 +#define INODEv3_FIELDS_START_CUR (offsetof(struct bch_inode_v3, fields) / sizeof(__u64)) + +struct bch_inode_generation { + struct bch_val v; + + __le32 bi_generation; + __le32 pad; +} __packed __aligned(8); + +/* + * bi_subvol and bi_parent_subvol are only set for subvolume roots: + */ + +#define BCH_INODE_FIELDS_v2() \ + x(bi_atime, 96) \ + x(bi_ctime, 96) \ + x(bi_mtime, 96) \ + x(bi_otime, 96) \ + x(bi_size, 64) \ + x(bi_sectors, 64) \ + x(bi_uid, 32) \ + x(bi_gid, 32) \ + x(bi_nlink, 32) \ + x(bi_generation, 32) \ + x(bi_dev, 32) \ + x(bi_data_checksum, 8) \ + x(bi_compression, 8) \ + x(bi_project, 32) \ + x(bi_background_compression, 8) \ + x(bi_data_replicas, 8) \ + x(bi_promote_target, 16) \ + x(bi_foreground_target, 16) \ + x(bi_background_target, 16) \ + x(bi_erasure_code, 16) \ + x(bi_fields_set, 16) \ + x(bi_dir, 64) \ + x(bi_dir_offset, 64) \ + x(bi_subvol, 32) \ + x(bi_parent_subvol, 32) + +#define BCH_INODE_FIELDS_v3() \ + x(bi_atime, 96) \ + x(bi_ctime, 96) \ + x(bi_mtime, 96) \ + x(bi_otime, 96) \ + x(bi_uid, 32) \ + x(bi_gid, 32) \ + x(bi_nlink, 32) \ + x(bi_generation, 32) \ + x(bi_dev, 32) \ + x(bi_data_checksum, 8) \ + x(bi_compression, 8) \ + x(bi_project, 32) \ + x(bi_background_compression, 8) \ + x(bi_data_replicas, 8) \ + x(bi_promote_target, 16) \ + x(bi_foreground_target, 16) \ + x(bi_background_target, 16) \ + x(bi_erasure_code, 16) \ + x(bi_fields_set, 16) \ + x(bi_dir, 64) \ + x(bi_dir_offset, 64) \ + x(bi_subvol, 32) \ + x(bi_parent_subvol, 32) \ + x(bi_nocow, 8) + +/* subset of BCH_INODE_FIELDS */ +#define BCH_INODE_OPTS() \ + x(data_checksum, 8) \ + x(compression, 8) \ + x(project, 32) \ + x(background_compression, 8) \ + x(data_replicas, 8) \ + x(promote_target, 16) \ + x(foreground_target, 16) \ + x(background_target, 16) \ + x(erasure_code, 16) \ + x(nocow, 8) + +enum inode_opt_id { +#define x(name, ...) \ + Inode_opt_##name, + BCH_INODE_OPTS() +#undef x + Inode_opt_nr, +}; + +#define BCH_INODE_FLAGS() \ + x(sync, 0) \ + x(immutable, 1) \ + x(append, 2) \ + x(nodump, 3) \ + x(noatime, 4) \ + x(i_size_dirty, 5) \ + x(i_sectors_dirty, 6) \ + x(unlinked, 7) \ + x(backptr_untrusted, 8) + +/* bits 20+ reserved for packed fields below: */ + +enum bch_inode_flags { +#define x(t, n) BCH_INODE_##t = 1U << n, + BCH_INODE_FLAGS() +#undef x +}; + +enum __bch_inode_flags { +#define x(t, n) __BCH_INODE_##t = n, + BCH_INODE_FLAGS() +#undef x +}; + +LE32_BITMASK(INODE_STR_HASH, struct bch_inode, bi_flags, 20, 24); +LE32_BITMASK(INODE_NR_FIELDS, struct bch_inode, bi_flags, 24, 31); +LE32_BITMASK(INODE_NEW_VARINT, struct bch_inode, bi_flags, 31, 32); + +LE64_BITMASK(INODEv2_STR_HASH, struct bch_inode_v2, bi_flags, 20, 24); +LE64_BITMASK(INODEv2_NR_FIELDS, struct bch_inode_v2, bi_flags, 24, 31); + +LE64_BITMASK(INODEv3_STR_HASH, struct bch_inode_v3, bi_flags, 20, 24); +LE64_BITMASK(INODEv3_NR_FIELDS, struct bch_inode_v3, bi_flags, 24, 31); + +LE64_BITMASK(INODEv3_FIELDS_START, + struct bch_inode_v3, bi_flags, 31, 36); +LE64_BITMASK(INODEv3_MODE, struct bch_inode_v3, bi_flags, 36, 52); + +/* Dirents */ + +/* + * Dirents (and xattrs) have to implement string lookups; since our b-tree + * doesn't support arbitrary length strings for the key, we instead index by a + * 64 bit hash (currently truncated sha1) of the string, stored in the offset + * field of the key - using linear probing to resolve hash collisions. This also + * provides us with the readdir cookie posix requires. + * + * Linear probing requires us to use whiteouts for deletions, in the event of a + * collision: + */ + +struct bch_dirent { + struct bch_val v; + + /* Target inode number: */ + union { + __le64 d_inum; + struct { /* DT_SUBVOL */ + __le32 d_child_subvol; + __le32 d_parent_subvol; + }; + }; + + /* + * Copy of mode bits 12-15 from the target inode - so userspace can get + * the filetype without having to do a stat() + */ + __u8 d_type; + + __u8 d_name[]; +} __packed __aligned(8); + +#define DT_SUBVOL 16 +#define BCH_DT_MAX 17 + +#define BCH_NAME_MAX 512 + +/* Xattrs */ + +#define KEY_TYPE_XATTR_INDEX_USER 0 +#define KEY_TYPE_XATTR_INDEX_POSIX_ACL_ACCESS 1 +#define KEY_TYPE_XATTR_INDEX_POSIX_ACL_DEFAULT 2 +#define KEY_TYPE_XATTR_INDEX_TRUSTED 3 +#define KEY_TYPE_XATTR_INDEX_SECURITY 4 + +struct bch_xattr { + struct bch_val v; + __u8 x_type; + __u8 x_name_len; + __le16 x_val_len; + __u8 x_name[]; +} __packed __aligned(8); + +/* Bucket/allocation information: */ + +struct bch_alloc { + struct bch_val v; + __u8 fields; + __u8 gen; + __u8 data[]; +} __packed __aligned(8); + +#define BCH_ALLOC_FIELDS_V1() \ + x(read_time, 16) \ + x(write_time, 16) \ + x(data_type, 8) \ + x(dirty_sectors, 16) \ + x(cached_sectors, 16) \ + x(oldest_gen, 8) \ + x(stripe, 32) \ + x(stripe_redundancy, 8) + +enum { +#define x(name, _bits) BCH_ALLOC_FIELD_V1_##name, + BCH_ALLOC_FIELDS_V1() +#undef x +}; + +struct bch_alloc_v2 { + struct bch_val v; + __u8 nr_fields; + __u8 gen; + __u8 oldest_gen; + __u8 data_type; + __u8 data[]; +} __packed __aligned(8); + +#define BCH_ALLOC_FIELDS_V2() \ + x(read_time, 64) \ + x(write_time, 64) \ + x(dirty_sectors, 32) \ + x(cached_sectors, 32) \ + x(stripe, 32) \ + x(stripe_redundancy, 8) + +struct bch_alloc_v3 { + struct bch_val v; + __le64 journal_seq; + __le32 flags; + __u8 nr_fields; + __u8 gen; + __u8 oldest_gen; + __u8 data_type; + __u8 data[]; +} __packed __aligned(8); + +LE32_BITMASK(BCH_ALLOC_V3_NEED_DISCARD,struct bch_alloc_v3, flags, 0, 1) +LE32_BITMASK(BCH_ALLOC_V3_NEED_INC_GEN,struct bch_alloc_v3, flags, 1, 2) + +struct bch_alloc_v4 { + struct bch_val v; + __u64 journal_seq; + __u32 flags; + __u8 gen; + __u8 oldest_gen; + __u8 data_type; + __u8 stripe_redundancy; + __u32 dirty_sectors; + __u32 cached_sectors; + __u64 io_time[2]; + __u32 stripe; + __u32 nr_external_backpointers; + __u64 fragmentation_lru; +} __packed __aligned(8); + +#define BCH_ALLOC_V4_U64s_V0 6 +#define BCH_ALLOC_V4_U64s (sizeof(struct bch_alloc_v4) / sizeof(__u64)) + +BITMASK(BCH_ALLOC_V4_NEED_DISCARD, struct bch_alloc_v4, flags, 0, 1) +BITMASK(BCH_ALLOC_V4_NEED_INC_GEN, struct bch_alloc_v4, flags, 1, 2) +BITMASK(BCH_ALLOC_V4_BACKPOINTERS_START,struct bch_alloc_v4, flags, 2, 8) +BITMASK(BCH_ALLOC_V4_NR_BACKPOINTERS, struct bch_alloc_v4, flags, 8, 14) + +#define BCH_ALLOC_V4_NR_BACKPOINTERS_MAX 40 + +struct bch_backpointer { + struct bch_val v; + __u8 btree_id; + __u8 level; + __u8 data_type; + __u64 bucket_offset:40; + __u32 bucket_len; + struct bpos pos; +} __packed __aligned(8); + +#define KEY_TYPE_BUCKET_GENS_BITS 8 +#define KEY_TYPE_BUCKET_GENS_NR (1U << KEY_TYPE_BUCKET_GENS_BITS) +#define KEY_TYPE_BUCKET_GENS_MASK (KEY_TYPE_BUCKET_GENS_NR - 1) + +struct bch_bucket_gens { + struct bch_val v; + u8 gens[KEY_TYPE_BUCKET_GENS_NR]; +} __packed __aligned(8); + +/* Quotas: */ + +enum quota_types { + QTYP_USR = 0, + QTYP_GRP = 1, + QTYP_PRJ = 2, + QTYP_NR = 3, +}; + +enum quota_counters { + Q_SPC = 0, + Q_INO = 1, + Q_COUNTERS = 2, +}; + +struct bch_quota_counter { + __le64 hardlimit; + __le64 softlimit; +}; + +struct bch_quota { + struct bch_val v; + struct bch_quota_counter c[Q_COUNTERS]; +} __packed __aligned(8); + +/* Erasure coding */ + +struct bch_stripe { + struct bch_val v; + __le16 sectors; + __u8 algorithm; + __u8 nr_blocks; + __u8 nr_redundant; + + __u8 csum_granularity_bits; + __u8 csum_type; + __u8 pad; + + struct bch_extent_ptr ptrs[]; +} __packed __aligned(8); + +/* Reflink: */ + +struct bch_reflink_p { + struct bch_val v; + __le64 idx; + /* + * A reflink pointer might point to an indirect extent which is then + * later split (by copygc or rebalance). If we only pointed to part of + * the original indirect extent, and then one of the fragments is + * outside the range we point to, we'd leak a refcount: so when creating + * reflink pointers, we need to store pad values to remember the full + * range we were taking a reference on. + */ + __le32 front_pad; + __le32 back_pad; +} __packed __aligned(8); + +struct bch_reflink_v { + struct bch_val v; + __le64 refcount; + union bch_extent_entry start[0]; + __u64 _data[]; +} __packed __aligned(8); + +struct bch_indirect_inline_data { + struct bch_val v; + __le64 refcount; + u8 data[]; +}; + +/* Inline data */ + +struct bch_inline_data { + struct bch_val v; + u8 data[]; +}; + +/* Subvolumes: */ + +#define SUBVOL_POS_MIN POS(0, 1) +#define SUBVOL_POS_MAX POS(0, S32_MAX) +#define BCACHEFS_ROOT_SUBVOL 1 + +struct bch_subvolume { + struct bch_val v; + __le32 flags; + __le32 snapshot; + __le64 inode; + /* + * Snapshot subvolumes form a tree, separate from the snapshot nodes + * tree - if this subvolume is a snapshot, this is the ID of the + * subvolume it was created from: + */ + __le32 parent; + __le32 pad; + bch_le128 otime; +}; + +LE32_BITMASK(BCH_SUBVOLUME_RO, struct bch_subvolume, flags, 0, 1) +/* + * We need to know whether a subvolume is a snapshot so we can know whether we + * can delete it (or whether it should just be rm -rf'd) + */ +LE32_BITMASK(BCH_SUBVOLUME_SNAP, struct bch_subvolume, flags, 1, 2) +LE32_BITMASK(BCH_SUBVOLUME_UNLINKED, struct bch_subvolume, flags, 2, 3) + +/* Snapshots */ + +struct bch_snapshot { + struct bch_val v; + __le32 flags; + __le32 parent; + __le32 children[2]; + __le32 subvol; + /* corresponds to a bch_snapshot_tree in BTREE_ID_snapshot_trees */ + __le32 tree; + __le32 depth; + __le32 skip[3]; +}; + +LE32_BITMASK(BCH_SNAPSHOT_DELETED, struct bch_snapshot, flags, 0, 1) + +/* True if a subvolume points to this snapshot node: */ +LE32_BITMASK(BCH_SNAPSHOT_SUBVOL, struct bch_snapshot, flags, 1, 2) + +/* + * Snapshot trees: + * + * The snapshot_trees btree gives us persistent indentifier for each tree of + * bch_snapshot nodes, and allow us to record and easily find the root/master + * subvolume that other snapshots were created from: + */ +struct bch_snapshot_tree { + struct bch_val v; + __le32 master_subvol; + __le32 root_snapshot; +}; + +/* LRU btree: */ + +struct bch_lru { + struct bch_val v; + __le64 idx; +} __packed __aligned(8); + +#define LRU_ID_STRIPES (1U << 16) + +/* Logged operations btree: */ + +struct bch_logged_op_truncate { + struct bch_val v; + __le32 subvol; + __le32 pad; + __le64 inum; + __le64 new_i_size; +}; + +enum logged_op_finsert_state { + LOGGED_OP_FINSERT_start, + LOGGED_OP_FINSERT_shift_extents, + LOGGED_OP_FINSERT_finish, +}; + +struct bch_logged_op_finsert { + struct bch_val v; + __u8 |