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Diffstat (limited to 'libbcachefs/bcachefs_format.h')
| -rw-r--r-- | libbcachefs/bcachefs_format.h | 1352 |
1 files changed, 1352 insertions, 0 deletions
diff --git a/libbcachefs/bcachefs_format.h b/libbcachefs/bcachefs_format.h new file mode 100644 index 00000000..0a0dc870 --- /dev/null +++ b/libbcachefs/bcachefs_format.h @@ -0,0 +1,1352 @@ +#ifndef _LINUX_BCACHE_H +#define _LINUX_BCACHE_H + +/* + * Bcache on disk data structures + */ + +#ifdef __cplusplus +typedef bool _Bool; +extern "C" { +#endif + +#include <asm/types.h> +#include <asm/byteorder.h> +#include <linux/uuid.h> + +#define LE32_BITMASK(name, type, field, offset, end) \ +static const unsigned name##_OFFSET = offset; \ +static const unsigned name##_BITS = (end - offset); \ +static const __u64 name##_MAX = (1ULL << (end - offset)) - 1; \ + \ +static inline __u64 name(const type *k) \ +{ \ + return (__le32_to_cpu(k->field) >> offset) & \ + ~(~0ULL << (end - offset)); \ +} \ + \ +static inline void SET_##name(type *k, __u64 v) \ +{ \ + __u64 new = __le32_to_cpu(k->field); \ + \ + new &= ~(~(~0ULL << (end - offset)) << offset); \ + new |= (v & ~(~0ULL << (end - offset))) << offset; \ + k->field = __cpu_to_le32(new); \ +} + +#define LE64_BITMASK(name, type, field, offset, end) \ +static const unsigned name##_OFFSET = offset; \ +static const unsigned name##_BITS = (end - offset); \ +static const __u64 name##_MAX = (1ULL << (end - offset)) - 1; \ + \ +static inline __u64 name(const type *k) \ +{ \ + return (__le64_to_cpu(k->field) >> offset) & \ + ~(~0ULL << (end - offset)); \ +} \ + \ +static inline void SET_##name(type *k, __u64 v) \ +{ \ + __u64 new = __le64_to_cpu(k->field); \ + \ + new &= ~(~(~0ULL << (end - offset)) << offset); \ + new |= (v & ~(~0ULL << (end - offset))) << offset; \ + k->field = __cpu_to_le64(new); \ +} + +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 */ +#if defined(__LITTLE_ENDIAN) + __u32 snapshot; + __u64 offset; + __u64 inode; +#elif defined(__BIG_ENDIAN) + __u64 inode; + __u64 offset; /* Points to end of extent - sectors */ + __u32 snapshot; +#else +#error edit for your odd byteorder. +#endif +} __attribute__((packed, aligned(4))); + +#define KEY_INODE_MAX ((__u64)~0ULL) +#define KEY_OFFSET_MAX ((__u64)~0ULL) +#define KEY_SNAPSHOT_MAX ((__u32)~0U) + +static inline struct bpos POS(__u64 inode, __u64 offset) +{ + struct bpos ret; + + ret.inode = inode; + ret.offset = offset; + ret.snapshot = 0; + + return ret; +} + +#define POS_MIN POS(0, 0) +#define POS_MAX POS(KEY_INODE_MAX, KEY_OFFSET_MAX) + +/* Empty placeholder struct, for container_of() */ +struct bch_val { + __u64 __nothing[0]; +}; + +struct bversion { +#if defined(__LITTLE_ENDIAN) + __u64 lo; + __u32 hi; +#elif defined(__BIG_ENDIAN) + __u32 hi; + __u64 lo; +#endif +} __attribute__((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 defined(__LITTLE_ENDIAN) + __u8 pad[1]; + + struct bversion version; + __u32 size; /* extent size, in sectors */ + struct bpos p; +#elif defined(__BIG_ENDIAN) + struct bpos p; + __u32 size; /* extent size, in sectors */ + struct bversion version; + + __u8 pad[1]; +#endif +} __attribute__((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]; +} __attribute__((packed, aligned(8))); + +#define BKEY_U64s (sizeof(struct bkey) / sizeof(__u64)) +#define KEY_PACKED_BITS_START 24 + +#define KEY_SIZE_MAX ((__u32)~0U) + +#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]; + + union { + struct { + /* Size of combined key and value, in u64s */ + __u8 u64s; + }; + struct { + struct bkey k; + struct bch_val v; + }; + }; +}; + +#ifndef __cplusplus + +#define KEY(_inode, _offset, _size) \ +((struct bkey) { \ + .u64s = BKEY_U64s, \ + .format = KEY_FORMAT_CURRENT, \ + .p = POS(_inode, _offset), \ + .size = _size, \ +}) + +#else + +static inline struct bkey KEY(__u64 inode, __u64 offset, __u64 size) +{ + struct bkey ret; + + memset(&ret, 0, sizeof(ret)); + ret.u64s = BKEY_U64s; + ret.format = KEY_FORMAT_CURRENT; + ret.p.inode = inode; + ret.p.offset = offset; + ret.size = size; + + return ret; +} + +#endif + +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 { struct bkey_i key; __u64 key ## _pad[pad]; } + +#define BKEY_VAL_TYPE(name, nr) \ +struct bkey_i_##name { \ + union { \ + struct bkey k; \ + struct bkey_i k_i; \ + }; \ + struct bch_##name v; \ +} + +/* + * - 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. +*/ +#define KEY_TYPE_DELETED 0 +#define KEY_TYPE_DISCARD 1 +#define KEY_TYPE_ERROR 2 +#define KEY_TYPE_COOKIE 3 +#define KEY_TYPE_PERSISTENT_DISCARD 4 +#define KEY_TYPE_GENERIC_NR 128 + +struct bch_cookie { + struct bch_val v; + __le64 cookie; +}; +BKEY_VAL_TYPE(cookie, KEY_TYPE_COOKIE); + +/* 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 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; +} __attribute__((packed, aligned(8))); + +#define BCH_CSUM_NONE 0U +#define BCH_CSUM_CRC32C 1U +#define BCH_CSUM_CRC64 2U +#define BCH_CSUM_CHACHA20_POLY1305_80 3U +#define BCH_CSUM_CHACHA20_POLY1305_128 4U +#define BCH_CSUM_NR 5U + +static inline _Bool bch2_csum_type_is_encryption(unsigned type) +{ + switch (type) { + case BCH_CSUM_CHACHA20_POLY1305_80: + case BCH_CSUM_CHACHA20_POLY1305_128: + return true; + default: + return false; + } +} + +enum bch_extent_entry_type { + BCH_EXTENT_ENTRY_ptr = 0, + BCH_EXTENT_ENTRY_crc32 = 1, + BCH_EXTENT_ENTRY_crc64 = 2, + BCH_EXTENT_ENTRY_crc128 = 3, +}; + +#define BCH_EXTENT_ENTRY_MAX 4 + +/* 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 +} __attribute__((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; +} __attribute__((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:14, + offset:13, + _uncompressed_size:13, + _compressed_size:13, + type:3; +#endif + struct bch_csum csum; +} __attribute__((packed, aligned(8))); + +#define CRC128_SIZE_MAX (1U << 13) +#define CRC128_NONCE_MAX ((1U << 13) - 1) + +/* + * Max size of an extent that may require bouncing to read or write + * (checksummed, compressed): 64k + */ +#define BCH_ENCODED_EXTENT_MAX 128U + +/* + * @reservation - pointer hasn't been written to, just reserved + */ +struct bch_extent_ptr { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u64 type:1, + cached:1, + erasure_coded:1, + reservation:1, + offset:44, /* 8 petabytes */ + dev:8, + gen:8; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u64 gen:8, + dev:8, + offset:44, + reservation:1, + erasure_coded:1, + cached:1, + type:1; +#endif +} __attribute__((packed, aligned(8))); + +struct bch_extent_reservation { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u64 type:5, + unused:23, + replicas:4, + generation:32; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u64 generation:32, + replicas:4, + unused:23, + type:5; +#endif +}; + +union bch_extent_entry { +#if defined(__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 + struct bch_extent_crc32 crc32; + struct bch_extent_crc64 crc64; + struct bch_extent_crc128 crc128; + struct bch_extent_ptr ptr; +}; + +enum { + BCH_EXTENT = 128, + + /* + * This is kind of a hack, we're overloading the type for a boolean that + * really should be part of the value - BCH_EXTENT and BCH_EXTENT_CACHED + * have the same value type: + */ + BCH_EXTENT_CACHED = 129, + + /* + * Persistent reservation: + */ + BCH_RESERVATION = 130, +}; + +struct bch_extent { + struct bch_val v; + + union bch_extent_entry start[0]; + __u64 _data[0]; +} __attribute__((packed, aligned(8))); +BKEY_VAL_TYPE(extent, BCH_EXTENT); + +struct bch_reservation { + struct bch_val v; + + __le32 generation; + __u8 nr_replicas; + __u8 pad[3]; +} __attribute__((packed, aligned(8))); +BKEY_VAL_TYPE(reservation, BCH_RESERVATION); + +/* 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: */ +/* There's a hack in the keylist code that needs to be fixed.. */ +#define BKEY_EXTENT_VAL_U64s_MAX \ + (BKEY_EXTENT_PTR_U64s_MAX * BCH_REPLICAS_MAX) + +/* * 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_extent_ptr)) / sizeof(u64) * BCH_REPLICAS_MAX) +#define BKEY_BTREE_PTR_U64s_MAX \ + (BKEY_U64s + BKEY_BTREE_PTR_VAL_U64s_MAX) + +/* Inodes */ + +#define BLOCKDEV_INODE_MAX 4096 + +#define BCACHE_ROOT_INO 4096 + +enum bch_inode_types { + BCH_INODE_FS = 128, + BCH_INODE_BLOCKDEV = 129, +}; + +struct bch_inode { + struct bch_val v; + + __le64 i_hash_seed; + __le32 i_flags; + __le16 i_mode; + __u8 fields[0]; +} __attribute__((packed)); +BKEY_VAL_TYPE(inode, BCH_INODE_FS); + +#define BCH_INODE_FIELDS() \ + BCH_INODE_FIELD(i_atime, 64) \ + BCH_INODE_FIELD(i_ctime, 64) \ + BCH_INODE_FIELD(i_mtime, 64) \ + BCH_INODE_FIELD(i_otime, 64) \ + BCH_INODE_FIELD(i_size, 64) \ + BCH_INODE_FIELD(i_sectors, 64) \ + BCH_INODE_FIELD(i_uid, 32) \ + BCH_INODE_FIELD(i_gid, 32) \ + BCH_INODE_FIELD(i_nlink, 32) \ + BCH_INODE_FIELD(i_generation, 32) \ + BCH_INODE_FIELD(i_dev, 32) + +enum { + /* + * User flags (get/settable with FS_IOC_*FLAGS, correspond to FS_*_FL + * flags) + */ + __BCH_INODE_SYNC = 0, + __BCH_INODE_IMMUTABLE = 1, + __BCH_INODE_APPEND = 2, + __BCH_INODE_NODUMP = 3, + __BCH_INODE_NOATIME = 4, + + __BCH_INODE_I_SIZE_DIRTY= 5, + __BCH_INODE_I_SECTORS_DIRTY= 6, + + /* not implemented yet: */ + __BCH_INODE_HAS_XATTRS = 7, /* has xattrs in xattr btree */ + + /* bits 20+ reserved for packed fields below: */ +}; + +#define BCH_INODE_SYNC (1 << __BCH_INODE_SYNC) +#define BCH_INODE_IMMUTABLE (1 << __BCH_INODE_IMMUTABLE) +#define BCH_INODE_APPEND (1 << __BCH_INODE_APPEND) +#define BCH_INODE_NODUMP (1 << __BCH_INODE_NODUMP) +#define BCH_INODE_NOATIME (1 << __BCH_INODE_NOATIME) +#define BCH_INODE_I_SIZE_DIRTY (1 << __BCH_INODE_I_SIZE_DIRTY) +#define BCH_INODE_I_SECTORS_DIRTY (1 << __BCH_INODE_I_SECTORS_DIRTY) +#define BCH_INODE_HAS_XATTRS (1 << __BCH_INODE_HAS_XATTRS) + +LE32_BITMASK(INODE_STR_HASH, struct bch_inode, i_flags, 20, 24); +LE32_BITMASK(INODE_NR_FIELDS, struct bch_inode, i_flags, 24, 32); + +struct bch_inode_blockdev { + struct bch_val v; + + __le64 i_size; + __le64 i_flags; + + /* Seconds: */ + __le64 i_ctime; + __le64 i_mtime; + + uuid_le i_uuid; + __u8 i_label[32]; +} __attribute__((packed, aligned(8))); +BKEY_VAL_TYPE(inode_blockdev, BCH_INODE_BLOCKDEV); + +/* Thin provisioned volume, or cache for another block device? */ +LE64_BITMASK(CACHED_DEV, struct bch_inode_blockdev, i_flags, 0, 1) + +/* 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: + */ + +enum { + BCH_DIRENT = 128, + BCH_DIRENT_WHITEOUT = 129, +}; + +struct bch_dirent { + struct bch_val v; + + /* Target inode number: */ + __le64 d_inum; + + /* + * 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[]; +} __attribute__((packed)); +BKEY_VAL_TYPE(dirent, BCH_DIRENT); + +/* Xattrs */ + +enum { + BCH_XATTR = 128, + BCH_XATTR_WHITEOUT = 129, +}; + +#define BCH_XATTR_INDEX_USER 0 +#define BCH_XATTR_INDEX_POSIX_ACL_ACCESS 1 +#define BCH_XATTR_INDEX_POSIX_ACL_DEFAULT 2 +#define BCH_XATTR_INDEX_TRUSTED 3 +#define BCH_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[]; +} __attribute__((packed)); +BKEY_VAL_TYPE(xattr, BCH_XATTR); + +/* Superblock */ + +/* Version 0: Cache device + * Version 1: Backing device + * Version 2: Seed pointer into btree node checksum + * Version 3: Cache device with new UUID format + * Version 4: Backing device with data offset + * Version 5: All the incompat changes + * Version 6: Cache device UUIDs all in superblock, another incompat bset change + * Version 7: Encryption (expanded checksum fields), other random things + */ +#define BCACHE_SB_VERSION_CDEV_V0 0 +#define BCACHE_SB_VERSION_BDEV 1 +#define BCACHE_SB_VERSION_CDEV_WITH_UUID 3 +#define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4 +#define BCACHE_SB_VERSION_CDEV_V2 5 +#define BCACHE_SB_VERSION_CDEV_V3 6 +#define BCACHE_SB_VERSION_CDEV_V4 7 +#define BCACHE_SB_VERSION_CDEV 7 +#define BCACHE_SB_MAX_VERSION 7 + +#define BCH_SB_SECTOR 8 +#define BCH_SB_LABEL_SIZE 32 +#define BCH_SB_MEMBERS_MAX 64 /* XXX kill */ + +struct bch_member { + uuid_le uuid; + __le64 nbuckets; /* device size */ + __le16 first_bucket; /* index of first bucket used */ + __le16 bucket_size; /* sectors */ + __le32 pad; + __le64 last_mount; /* time_t */ + + __le64 flags[2]; +}; + +LE64_BITMASK(BCH_MEMBER_STATE, struct bch_member, flags[0], 0, 4) +LE64_BITMASK(BCH_MEMBER_TIER, struct bch_member, flags[0], 4, 8) +LE64_BITMASK(BCH_MEMBER_HAS_METADATA, struct bch_member, flags[0], 8, 9) +LE64_BITMASK(BCH_MEMBER_HAS_DATA, struct bch_member, flags[0], 9, 10) +LE64_BITMASK(BCH_MEMBER_REPLACEMENT, struct bch_member, flags[0], 10, 14) +LE64_BITMASK(BCH_MEMBER_DISCARD, struct bch_member, flags[0], 14, 15); + +#if 0 +LE64_BITMASK(BCH_MEMBER_NR_READ_ERRORS, struct bch_member, flags[1], 0, 20); +LE64_BITMASK(BCH_MEMBER_NR_WRITE_ERRORS,struct bch_member, flags[1], 20, 40); +#endif + +enum bch_member_state { + BCH_MEMBER_STATE_RW = 0, + BCH_MEMBER_STATE_RO = 1, + BCH_MEMBER_STATE_FAILED = 2, + BCH_MEMBER_STATE_SPARE = 3, + BCH_MEMBER_STATE_NR = 4, +}; + +#define BCH_TIER_MAX 4U + +enum cache_replacement { + CACHE_REPLACEMENT_LRU = 0, + CACHE_REPLACEMENT_FIFO = 1, + CACHE_REPLACEMENT_RANDOM = 2, + CACHE_REPLACEMENT_NR = 3, +}; + +struct bch_sb_layout { + uuid_le magic; /* bcachefs superblock UUID */ + __u8 layout_type; + __u8 sb_max_size_bits; /* base 2 of 512 byte sectors */ + __u8 nr_superblocks; + __u8 pad[5]; + __u64 sb_offset[61]; +} __attribute__((packed)); + +#define BCH_SB_LAYOUT_SECTOR 7 + +struct bch_sb_field { + __u64 _data[0]; + __le32 u64s; + __le32 type; +}; + +enum bch_sb_field_type { + BCH_SB_FIELD_journal = 0, + BCH_SB_FIELD_members = 1, + BCH_SB_FIELD_crypt = 2, + BCH_SB_FIELD_NR = 3, +}; + +struct bch_sb_field_journal { + struct bch_sb_field field; + __le64 buckets[0]; +}; + +struct bch_sb_field_members { + struct bch_sb_field field; + struct bch_member members[0]; +}; + +/* Crypto: */ + +struct nonce { + __le32 d[4]; +}; + +struct bch_key { + __le64 key[4]; +}; + +#define BCH_KEY_MAGIC \ + (((u64) 'b' << 0)|((u64) 'c' << 8)| \ + ((u64) 'h' << 16)|((u64) '*' << 24)| \ + ((u64) '*' << 32)|((u64) 'k' << 40)| \ + ((u64) 'e' << 48)|((u64) 'y' << 56)) + +struct bch_encrypted_key { + __le64 magic; + struct bch_key key; +}; + +/* + * If this field is present in the superblock, it stores an encryption key which + * is used encrypt all other data/metadata. The key will normally be encrypted + * with the key userspace provides, but if encryption has been turned off we'll + * just store the master key unencrypted in the superblock so we can access the + * previously encrypted data. + */ +struct bch_sb_field_crypt { + struct bch_sb_field field; + + __le64 flags; + __le64 kdf_flags; + struct bch_encrypted_key key; +}; + +LE64_BITMASK(BCH_CRYPT_KDF_TYPE, struct bch_sb_field_crypt, flags, 0, 4); + +enum bch_kdf_types { + BCH_KDF_SCRYPT = 0, + BCH_KDF_NR = 1, +}; + +/* stored as base 2 log of scrypt params: */ +LE64_BITMASK(BCH_KDF_SCRYPT_N, struct bch_sb_field_crypt, kdf_flags, 0, 16); +LE64_BITMASK(BCH_KDF_SCRYPT_R, struct bch_sb_field_crypt, kdf_flags, 16, 32); +LE64_BITMASK(BCH_KDF_SCRYPT_P, struct bch_sb_field_crypt, kdf_flags, 32, 48); + +struct bch_sb_field_replication { + struct bch_sb_field field; +}; + +/* + * @offset - sector where this sb was written + * @version - on disk format version + * @magic - identifies as a bcachefs superblock (BCACHE_MAGIC) + * @seq - incremented each time superblock is written + * @uuid - used for generating various magic numbers and identifying + * member devices, never changes + * @user_uuid - user visible UUID, may be changed + * @label - filesystem label + * @seq - identifies most recent superblock, incremented each time + * superblock is written + * @features - enabled incompatible features + */ +struct bch_sb { + struct bch_csum csum; + __le64 version; + uuid_le magic; + uuid_le uuid; + uuid_le user_uuid; + __u8 label[BCH_SB_LABEL_SIZE]; + __le64 offset; + __le64 seq; + + __le16 block_size; + __u8 dev_idx; + __u8 nr_devices; + __le32 u64s; + + __le64 time_base_lo; + __le32 time_base_hi; + __le32 time_precision; + + __le64 flags[8]; + __le64 features[2]; + __le64 compat[2]; + + struct bch_sb_layout layout; + + union { + struct bch_sb_field start[0]; + __le64 _data[0]; + }; +} __attribute__((packed, aligned(8))); + +/* + * Flags: + * BCH_SB_INITALIZED - set on first mount + * BCH_SB_CLEAN - did we shut down cleanly? Just a hint, doesn't affect + * behaviour of mount/recovery path: + * BCH_SB_INODE_32BIT - limit inode numbers to 32 bits + * BCH_SB_128_BIT_MACS - 128 bit macs instead of 80 + * BCH_SB_ENCRYPTION_TYPE - if nonzero encryption is enabled; overrides + * DATA/META_CSUM_TYPE. Also indicates encryption + * algorithm in use, if/when we get more than one + */ + +LE64_BITMASK(BCH_SB_INITIALIZED, struct bch_sb, flags[0], 0, 1); +LE64_BITMASK(BCH_SB_CLEAN, struct bch_sb, flags[0], 1, 2); +LE64_BITMASK(BCH_SB_CSUM_TYPE, struct bch_sb, flags[0], 2, 8); +LE64_BITMASK(BCH_SB_ERROR_ACTION, struct bch_sb, flags[0], 8, 12); + +LE64_BITMASK(BCH_SB_BTREE_NODE_SIZE, struct bch_sb, flags[0], 12, 28); + +LE64_BITMASK(BCH_SB_GC_RESERVE, struct bch_sb, flags[0], 28, 33); +LE64_BITMASK(BCH_SB_ROOT_RESERVE, struct bch_sb, flags[0], 33, 40); + +LE64_BITMASK(BCH_SB_META_CSUM_TYPE, struct bch_sb, flags[0], 40, 44); +LE64_BITMASK(BCH_SB_DATA_CSUM_TYPE, struct bch_sb, flags[0], 44, 48); + +LE64_BITMASK(BCH_SB_META_REPLICAS_WANT, struct bch_sb, flags[0], 48, 52); +LE64_BITMASK(BCH_SB_DATA_REPLICAS_WANT, struct bch_sb, flags[0], 52, 56); + +LE64_BITMASK(BCH_SB_META_REPLICAS_HAVE, struct bch_sb, flags[0], 56, 60); +LE64_BITMASK(BCH_SB_DATA_REPLICAS_HAVE, struct bch_sb, flags[0], 60, 64); + +LE64_BITMASK(BCH_SB_STR_HASH_TYPE, struct bch_sb, flags[1], 0, 4); +LE64_BITMASK(BCH_SB_COMPRESSION_TYPE, struct bch_sb, flags[1], 4, 8); +LE64_BITMASK(BCH_SB_INODE_32BIT, struct bch_sb, flags[1], 8, 9); + +LE64_BITMASK(BCH_SB_128_BIT_MACS, struct bch_sb, flags[1], 9, 10); +LE64_BITMASK(BCH_SB_ENCRYPTION_TYPE, struct bch_sb, flags[1], 10, 14); +LE64_BITMASK(BCH_SB_JOURNAL_ENTRY_SIZE, struct bch_sb, flags[1], 14, 20); + +LE64_BITMASK(BCH_SB_META_REPLICAS_REQ, struct bch_sb, flags[1], 20, 24); +LE64_BITMASK(BCH_SB_DATA_REPLICAS_REQ, struct bch_sb, flags[1], 24, 28); + +/* Features: */ +enum bch_sb_features { + BCH_FEATURE_LZ4 = 0, + BCH_FEATURE_GZIP = 1, +}; + +/* options: */ + +#define BCH_REPLICAS_MAX 4U + +#if 0 +#define BCH_ERROR_ACTIONS() \ + x(BCH_ON_ERROR_CONTINUE, 0, "continue") \ + x(BCH_ON_ERROR_RO, 1, "remount-ro") \ + x(BCH_ON_ERROR_PANIC, 2, "panic") \ + x(BCH_NR_ERROR_ACTIONS, 3, NULL) + +enum bch_error_actions { +#define x(_opt, _nr, _str) _opt = _nr, + BCH_ERROR_ACTIONS() +#undef x +}; +#endif + +enum bch_error_actions { + BCH_ON_ERROR_CONTINUE = 0, + BCH_ON_ERROR_RO = 1, + BCH_ON_ERROR_PANIC = 2, + BCH_NR_ERROR_ACTIONS = 3, +}; + +enum bch_csum_opts { + BCH_CSUM_OPT_NONE = 0, + BCH_CSUM_OPT_CRC32C = 1, + BCH_CSUM_OPT_CRC64 = 2, + BCH_CSUM_OPT_NR = 3, +}; + +enum bch_str_hash_opts { + BCH_STR_HASH_CRC32C = 0, + BCH_STR_HASH_CRC64 = 1, + BCH_STR_HASH_SIPHASH = 2, + BCH_STR_HASH_NR = 3, +}; + +enum bch_compression_opts { + BCH_COMPRESSION_NONE = 0, + BCH_COMPRESSION_LZ4 = 1, + BCH_COMPRESSION_GZIP = 2, + BCH_COMPRESSION_NR = 3, +}; + +/* backing device specific stuff: */ + +struct backingdev_sb { + __le64 csum; + __le64 offset; /* sector where this sb was written */ + __le64 version; /* of on disk format */ + + uuid_le magic; /* bcachefs superblock UUID */ + + uuid_le disk_uuid; + + /* + * Internal cache set UUID - xored with various magic numbers and thus + * must never change: + */ + union { + uuid_le set_uuid; + __le64 set_magic; + }; + __u8 label[BCH_SB_LABEL_SIZE]; + + __le64 flags; + + /* Incremented each time superblock is written: */ + __le64 seq; + + /* + * User visible UUID for identifying the cache set the user is allowed + * to change: + * + * XXX hooked up? + */ + uuid_le user_uuid; + __le64 pad1[6]; + + __le64 data_offset; + __le16 block_size; /* sectors */ + __le16 pad2[3]; + + __le32 last_mount; /* time_t */ + __le16 pad3; + /* size of variable length portion - always 0 for backingdev superblock */ + __le16 u64s; + __u64 _data[0]; +}; + +LE64_BITMASK(BDEV_CACHE_MODE, struct backingdev_sb, flags, 0, 4); +#define CACHE_MODE_WRITETHROUGH 0U +#define CACHE_MODE_WRITEBACK 1U +#define CACHE_MODE_WRITEAROUND 2U +#define CACHE_MODE_NONE 3U + +LE64_BITMASK(BDEV_STATE, struct backingdev_sb, flags, 61, 63); +#define BDEV_STATE_NONE 0U +#define BDEV_STATE_CLEAN 1U +#define BDEV_STATE_DIRTY 2U +#define BDEV_STATE_STALE 3U + +#define BDEV_DATA_START_DEFAULT 16 /* sectors */ + +static inline _Bool __SB_IS_BDEV(__u64 version) +{ + return version == BCACHE_SB_VERSION_BDEV + || version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET; +} + +static inline _Bool SB_IS_BDEV(const struct bch_sb *sb) +{ + return __SB_IS_BDEV(sb->version); +} + +/* + * Magic numbers + * + * The various other data structures have their own magic numbers, which are + * xored with the first part of the cache set's UUID + */ + +#define BCACHE_MAGIC \ + UUID_LE(0xf67385c6, 0x1a4e, 0xca45, \ + 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81) + +#define BCACHE_STATFS_MAGIC 0xca451a4e + +#define JSET_MAGIC __cpu_to_le64(0x245235c1a3625032ULL) +#define PSET_MAGIC __cpu_to_le64(0x6750e15f87337f91ULL) +#define BSET_MAGIC __cpu_to_le64(0x90135c78b99e07f5ULL) + +static inline __le64 __bch2_sb_magic(struct bch_sb *sb) +{ + __le64 ret; + memcpy(&ret, &sb->uuid, sizeof(ret)); + return ret; +} + +static inline __u64 __jset_magic(struct bch_sb *sb) +{ + return __le64_to_cpu(__bch2_sb_magic(sb) ^ JSET_MAGIC); +} + +static inline __u64 __pset_magic(struct bch_sb *sb) +{ + return __le64_to_cpu(__bch2_sb_magic(sb) ^ PSET_MAGIC); +} + +static inline __u64 __bset_magic(struct bch_sb *sb) +{ + return __le64_to_cpu(__bch2_sb_magic(sb) ^ BSET_MAGIC); +} + +/* Journal */ + +#define BCACHE_JSET_VERSION_UUIDv1 1 +#define BCACHE_JSET_VERSION_UUID 1 /* Always latest UUID format */ +#define BCACHE_JSET_VERSION_JKEYS 2 +#define BCACHE_JSET_VERSION 2 + +struct jset_entry { + __le16 u64s; + __u8 btree_id; + __u8 level; + __le32 flags; /* designates what this jset holds */ + + union { + struct bkey_i start[0]; + __u64 _data[0]; + }; +}; + +#define JSET_KEYS_U64s (sizeof(struct jset_entry) / sizeof(__u64)) + +LE32_BITMASK(JOURNAL_ENTRY_TYPE, struct jset_entry, flags, 0, 8); +enum { + JOURNAL_ENTRY_BTREE_KEYS = 0, + JOURNAL_ENTRY_BTREE_ROOT = 1, + JOURNAL_ENTRY_PRIO_PTRS = 2, + + /* + * Journal sequence numbers can be blacklisted: bsets record the max + * sequence number of all the journal entries they contain updates for, + * so that on recovery we can ignore those bsets that contain index + * updates newer that what made it into the journal. + * + * This means that we can't reuse that journal_seq - we have to skip it, + * and then record that we skipped it so that the next time we crash and + * recover we don't think there was a missing journal entry. + */ + JOURNAL_ENTRY_JOURNAL_SEQ_BLACKLISTED = 3, +}; + +/* + * On disk format for a journal entry: + * seq is monotonically increasing; every journal entry has its own unique + * sequence number. + * + * last_seq is the oldest journal entry that still has keys the btree hasn't + * flushed to disk yet. + * + * version is for on disk format changes. + */ +struct jset { + struct bch_csum csum; + + __le64 magic; + __le64 seq; + __le32 version; + __le32 flags; + + __le32 u64s; /* size of d[] in u64s */ + + __u8 encrypted_start[0]; + + __le16 read_clock; + __le16 write_clock; + + /* Sequence number of oldest dirty journal entry */ + __le64 last_seq; + + + union { + struct jset_entry start[0]; + __u64 _data[0]; + }; +} __attribute__((packed)); + +LE32_BITMASK(JSET_CSUM_TYPE, struct jset, flags, 0, 4); +LE32_BITMASK(JSET_BIG_ENDIAN, struct jset, flags, 4, 5); + +#define BCH_JOURNAL_BUCKETS_MIN 20 + +/* Bucket prios/gens */ + +struct prio_set { + struct bch_csum csum; + + __le64 magic; + __le32 nonce[3]; + __le16 version; + __le16 flags; + + __u8 encrypted_start[0]; + + __le64 next_bucket; + + struct bucket_disk { + __le16 read_prio; + __le16 write_prio; + __u8 gen; + } __attribute__((packed)) data[]; +} __attribute__((packed)); + +LE32_BITMASK(PSET_CSUM_TYPE, struct prio_set, flags, 0, 4); + +/* Btree: */ + +#define DEFINE_BCH_BTREE_IDS() \ + DEF_BTREE_ID(EXTENTS, 0, "extents") \ + DEF_BTREE_ID(INODES, 1, "inodes") \ + DEF_BTREE_ID(DIRENTS, 2, "dirents") \ + DEF_BTREE_ID(XATTRS, 3, "xattrs") + +#define DEF_BTREE_ID(kwd, val, name) BTREE_ID_##kwd = val, + +enum btree_id { + DEFINE_BCH_BTREE_IDS() + BTREE_ID_NR +}; + +#undef DEF_BTREE_ID + +#define BTREE_MAX_DEPTH 4U + +/* Btree nodes */ + +/* Version 1: Seed pointer into btree node checksum + */ +#define BCACHE_BSET_CSUM 1 +#define BCACHE_BSET_KEY_v1 2 +#define BCACHE_BSET_JOURNAL_SEQ 3 +#define BCACHE_BSET_VERSION 3 + +/* + * Btree nodes + * + * On disk a btree node is a list/log of these; within each set the keys are + * sorted + */ +struct bset { + __le64 seq; + + /* + * Highest journal entry this bset contains keys for. + * If on recovery we don't see that journal entry, this bset is ignored: + * this allows us to preserve the order of all index updates after a + * crash, since the journal records a total order of all index updates + * and anything that didn't make it to the journal doesn't get used. + */ + __le64 journal_seq; + + __le32 flags; + __le16 version; + __le16 u64s; /* count of d[] in u64s */ + + union { + struct bkey_packed start[0]; + __u64 _data[0]; + }; +} __attribute__((packed)); + +LE32_BITMASK(BSET_CSUM_TYPE, struct bset, flags, 0, 4); + +LE32_BITMASK(BSET_BIG_ENDIAN, struct bset, flags, 4, 5); +LE32_BITMASK(BSET_SEPARATE_WHITEOUTS, + struct bset, flags, 5, 6); + +struct btree_node { + struct bch_csum csum; + __le64 magic; + + /* this flags field is encrypted, unlike bset->flags: */ + __le64 flags; + + /* Closed interval: */ + struct bpos min_key; + struct bpos max_key; + struct bch_extent_ptr ptr; + struct bkey_format format; + + union { + struct bset keys; + struct { + __u8 pad[22]; + __le16 u64s; + __u64 _data[0]; + + }; + }; +} __attribute__((packed)); + +LE64_BITMASK(BTREE_NODE_ID, struct btree_node, flags, 0, 4); +LE64_BITMASK(BTREE_NODE_LEVEL, struct btree_node, flags, 4, 8); + +struct btree_node_entry { + struct bch_csum csum; + + union { + struct bset keys; + struct { + __u8 pad[22]; + __le16 u64s; + __u64 _data[0]; + + }; + }; +} __attribute__((packed)); + +#ifdef __cplusplus +} +#endif +#endif /* _LINUX_BCACHE_H */ + +/* vim: set foldnestmax=2: */ |