[PATCH 1/2] bcachefs: On disk data structures
From: Kent Overstreet
Date: Tue May 08 2018 - 18:18:40 EST
Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
---
fs/bcachefs/bcachefs_format.h | 1448 +++++++++++++++++++++++++++++++++
1 file changed, 1448 insertions(+)
create mode 100644 fs/bcachefs/bcachefs_format.h
diff --git a/fs/bcachefs/bcachefs_format.h b/fs/bcachefs/bcachefs_format.h
new file mode 100644
index 0000000000..0961585c7e
--- /dev/null
+++ b/fs/bcachefs/bcachefs_format.h
@@ -0,0 +1,1448 @@
+#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/uuid.h>
+
+#define LE_BITMASK(_bits, name, type, field, offset, end) \
+static const unsigned name##_OFFSET = offset; \
+static const unsigned name##_BITS = (end - offset); \
+static const __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 */
+#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)
+#define KEY_SIZE_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_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;
+ };
+ };
+};
+
+#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 { 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)));
+
+enum bch_csum_type {
+ BCH_CSUM_NONE = 0,
+ BCH_CSUM_CRC32C_NONZERO = 1,
+ BCH_CSUM_CRC64_NONZERO = 2,
+ BCH_CSUM_CHACHA20_POLY1305_80 = 3,
+ BCH_CSUM_CHACHA20_POLY1305_128 = 4,
+ BCH_CSUM_CRC32C = 5,
+ BCH_CSUM_CRC64 = 6,
+ BCH_CSUM_NR = 7,
+};
+
+static inline _Bool bch2_csum_type_is_encryption(enum bch_csum_type type)
+{
+ switch (type) {
+ case BCH_CSUM_CHACHA20_POLY1305_80:
+ case BCH_CSUM_CHACHA20_POLY1305_128:
+ return true;
+ default:
+ return false;
+ }
+}
+
+enum bch_compression_type {
+ BCH_COMPRESSION_NONE = 0,
+ BCH_COMPRESSION_LZ4_OLD = 1,
+ BCH_COMPRESSION_GZIP = 2,
+ BCH_COMPRESSION_LZ4 = 3,
+ BCH_COMPRESSION_ZSTD = 4,
+ BCH_COMPRESSION_NR = 5,
+};
+
+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)
+
+/*
+ * @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: */
+#define BKEY_EXTENT_VAL_U64s_MAX \
+ (BKEY_EXTENT_PTR_U64s_MAX * (BCH_REPLICAS_MAX + 1))
+
+#define BKEY_PADDED(key) __BKEY_PADDED(key, BKEY_EXTENT_VAL_U64s_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 BCACHEFS_ROOT_INO 4096
+
+enum bch_inode_types {
+ BCH_INODE_FS = 128,
+ BCH_INODE_BLOCKDEV = 129,
+ BCH_INODE_GENERATION = 130,
+};
+
+struct bch_inode {
+ struct bch_val v;
+
+ __le64 bi_hash_seed;
+ __le32 bi_flags;
+ __le16 bi_mode;
+ __u8 fields[0];
+} __attribute__((packed, aligned(8)));
+BKEY_VAL_TYPE(inode, BCH_INODE_FS);
+
+struct bch_inode_generation {
+ struct bch_val v;
+
+ __le32 bi_generation;
+ __le32 pad;
+} __attribute__((packed, aligned(8)));
+BKEY_VAL_TYPE(inode_generation, BCH_INODE_GENERATION);
+
+#define BCH_INODE_FIELDS() \
+ BCH_INODE_FIELD(bi_atime, 64) \
+ BCH_INODE_FIELD(bi_ctime, 64) \
+ BCH_INODE_FIELD(bi_mtime, 64) \
+ BCH_INODE_FIELD(bi_otime, 64) \
+ BCH_INODE_FIELD(bi_size, 64) \
+ BCH_INODE_FIELD(bi_sectors, 64) \
+ BCH_INODE_FIELD(bi_uid, 32) \
+ BCH_INODE_FIELD(bi_gid, 32) \
+ BCH_INODE_FIELD(bi_nlink, 32) \
+ BCH_INODE_FIELD(bi_generation, 32) \
+ BCH_INODE_FIELD(bi_dev, 32) \
+ BCH_INODE_FIELD(bi_data_checksum, 8) \
+ BCH_INODE_FIELD(bi_compression, 8) \
+ BCH_INODE_FIELD(bi_project, 32) \
+ BCH_INODE_FIELD(bi_background_compression, 8) \
+ BCH_INODE_FIELD(bi_data_replicas, 8) \
+ BCH_INODE_FIELD(bi_promote_target, 16) \
+ BCH_INODE_FIELD(bi_foreground_target, 16) \
+ BCH_INODE_FIELD(bi_background_target, 16)
+
+#define BCH_INODE_FIELDS_INHERIT() \
+ BCH_INODE_FIELD(bi_data_checksum) \
+ BCH_INODE_FIELD(bi_compression) \
+ BCH_INODE_FIELD(bi_project) \
+ BCH_INODE_FIELD(bi_background_compression) \
+ BCH_INODE_FIELD(bi_data_replicas) \
+ BCH_INODE_FIELD(bi_promote_target) \
+ BCH_INODE_FIELD(bi_foreground_target) \
+ BCH_INODE_FIELD(bi_background_target)
+
+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, bi_flags, 20, 24);
+LE32_BITMASK(INODE_NR_FIELDS, struct bch_inode, bi_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, aligned(8)));
+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, aligned(8)));
+BKEY_VAL_TYPE(xattr, BCH_XATTR);
+
+/* Bucket/allocation information: */
+
+enum {
+ BCH_ALLOC = 128,
+};
+
+enum {
+ BCH_ALLOC_FIELD_READ_TIME = 0,
+ BCH_ALLOC_FIELD_WRITE_TIME = 1,
+};
+
+struct bch_alloc {
+ struct bch_val v;
+ __u8 fields;
+ __u8 gen;
+ __u8 data[];
+} __attribute__((packed, aligned(8)));
+BKEY_VAL_TYPE(alloc, BCH_ALLOC);
+
+/* Quotas: */
+
+enum {
+ BCH_QUOTA = 128,
+};
+
+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];
+} __attribute__((packed, aligned(8)));
+BKEY_VAL_TYPE(quota, BCH_QUOTA);
+
+/* Optional/variable size superblock sections: */
+
+struct bch_sb_field {
+ __u64 _data[0];
+ __le32 u64s;
+ __le32 type;
+};
+
+#define BCH_SB_FIELDS() \
+ x(journal, 0) \
+ x(members, 1) \
+ x(crypt, 2) \
+ x(replicas, 3) \
+ x(quota, 4) \
+ x(disk_groups, 5)
+
+enum bch_sb_field_type {
+#define x(f, nr) BCH_SB_FIELD_##f = nr,
+ BCH_SB_FIELDS()
+#undef x
+ BCH_SB_FIELD_NR
+};
+
+/* BCH_SB_FIELD_journal: */
+
+struct bch_sb_field_journal {
+ struct bch_sb_field field;
+ __le64 buckets[0];
+};
+
+/* BCH_SB_FIELD_members: */
+
+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)
+/* 4-10 unused, was TIER, HAS_(META)DATA */
+LE64_BITMASK(BCH_MEMBER_REPLACEMENT, struct bch_member, flags[0], 10, 14)
+LE64_BITMASK(BCH_MEMBER_DISCARD, struct bch_member, flags[0], 14, 15)
+LE64_BITMASK(BCH_MEMBER_DATA_ALLOWED, struct bch_member, flags[0], 15, 20)
+LE64_BITMASK(BCH_MEMBER_GROUP, struct bch_member, flags[0], 20, 28)
+LE64_BITMASK(BCH_MEMBER_DURABILITY, struct bch_member, flags[0], 28, 30)
+
+#define BCH_TIER_MAX 4U
+
+#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,
+};
+
+enum cache_replacement {
+ CACHE_REPLACEMENT_LRU = 0,
+ CACHE_REPLACEMENT_FIFO = 1,
+ CACHE_REPLACEMENT_RANDOM = 2,
+ CACHE_REPLACEMENT_NR = 3,
+};
+
+struct bch_sb_field_members {
+ struct bch_sb_field field;
+ struct bch_member members[0];
+};
+
+/* BCH_SB_FIELD_crypt: */
+
+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);
+
+/* BCH_SB_FIELD_replicas: */
+
+enum bch_data_type {
+ BCH_DATA_NONE = 0,
+ BCH_DATA_SB = 1,
+ BCH_DATA_JOURNAL = 2,
+ BCH_DATA_BTREE = 3,
+ BCH_DATA_USER = 4,
+ BCH_DATA_CACHED = 5,
+ BCH_DATA_NR = 6,
+};
+
+struct bch_replicas_entry {
+ u8 data_type;
+ u8 nr;
+ u8 devs[0];
+};
+
+struct bch_sb_field_replicas {
+ struct bch_sb_field field;
+ struct bch_replicas_entry entries[0];
+};
+
+/* BCH_SB_FIELD_quota: */
+
+struct bch_sb_quota_counter {
+ __le32 timelimit;
+ __le32 warnlimit;
+};
+
+struct bch_sb_quota_type {
+ __le64 flags;
+ struct bch_sb_quota_counter c[Q_COUNTERS];
+};
+
+struct bch_sb_field_quota {
+ struct bch_sb_field field;
+ struct bch_sb_quota_type q[QTYP_NR];
+} __attribute__((packed, aligned(8)));
+
+/* BCH_SB_FIELD_disk_groups: */
+
+#define BCH_SB_LABEL_SIZE 32
+
+struct bch_disk_group {
+ __u8 label[BCH_SB_LABEL_SIZE];
+ __le64 flags[2];
+};
+
+LE64_BITMASK(BCH_GROUP_DELETED, struct bch_disk_group, flags[0], 0, 1)
+LE64_BITMASK(BCH_GROUP_DATA_ALLOWED, struct bch_disk_group, flags[0], 1, 6)
+LE64_BITMASK(BCH_GROUP_PARENT, struct bch_disk_group, flags[0], 6, 24)
+
+struct bch_sb_field_disk_groups {
+ struct bch_sb_field field;
+ struct bch_disk_group entries[0];
+};
+
+/* Superblock: */
+
+/*
+ * Version 8: BCH_SB_ENCODED_EXTENT_MAX_BITS
+ * BCH_MEMBER_DATA_ALLOWED
+ * Version 9: incompatible extent nonce change
+ */
+
+#define BCH_SB_VERSION_MIN 7
+#define BCH_SB_VERSION_EXTENT_MAX 8
+#define BCH_SB_VERSION_EXTENT_NONCE_V1 9
+#define BCH_SB_VERSION_MAX 9
+
+#define BCH_SB_SECTOR 8
+#define BCH_SB_MEMBERS_MAX 64 /* XXX kill */
+
+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];
+ __le64 sb_offset[61];
+} __attribute__((packed, aligned(8)));
+
+#define BCH_SB_LAYOUT_SECTOR 7
+
+/*
+ * @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
+ */
+
+LE16_BITMASK(BCH_SB_BLOCK_SIZE, struct bch_sb, block_size, 0, 16);
+
+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_POSIX_ACL, struct bch_sb, flags[0], 56, 57);
+LE64_BITMASK(BCH_SB_USRQUOTA, struct bch_sb, flags[0], 57, 58);
+LE64_BITMASK(BCH_SB_GRPQUOTA, struct bch_sb, flags[0], 58, 59);
+LE64_BITMASK(BCH_SB_PRJQUOTA, struct bch_sb, flags[0], 59, 60);
+
+/* 60-64 unused */
+
+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);
+
+/*
+ * Max size of an extent that may require bouncing to read or write
+ * (checksummed, compressed): 64k
+ */
+LE64_BITMASK(BCH_SB_ENCODED_EXTENT_MAX_BITS,
+ 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);
+
+LE64_BITMASK(BCH_SB_PROMOTE_TARGET, struct bch_sb, flags[1], 28, 40);
+LE64_BITMASK(BCH_SB_FOREGROUND_TARGET, struct bch_sb, flags[1], 40, 52);
+LE64_BITMASK(BCH_SB_BACKGROUND_TARGET, struct bch_sb, flags[1], 52, 64);
+
+LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE,
+ struct bch_sb, flags[2], 0, 4);
+
+/* Features: */
+enum bch_sb_features {
+ BCH_FEATURE_LZ4 = 0,
+ BCH_FEATURE_GZIP = 1,
+ BCH_FEATURE_ZSTD = 2,
+};
+
+/* options: */
+
+#define BCH_REPLICAS_MAX 4U
+
+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,
+};
+
+#define BCH_COMPRESSION_TYPES() \
+ x(NONE) \
+ x(LZ4) \
+ x(GZIP) \
+ x(ZSTD)
+
+enum bch_compression_opts {
+#define x(t) BCH_COMPRESSION_OPT_##t,
+ BCH_COMPRESSION_TYPES()
+#undef x
+ BCH_COMPRESSION_OPT_NR
+};
+
+/*
+ * 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 BCACHEFS_STATFS_MAGIC 0xca451a4e
+
+#define JSET_MAGIC __cpu_to_le64(0x245235c1a3625032ULL)
+#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 __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;
+ __u8 type; /* designates what this jset holds */
+ __u8 pad[3];
+
+ union {
+ struct bkey_i start[0];
+ __u64 _data[0];
+ };
+};
+
+#define JSET_KEYS_U64s (sizeof(struct jset_entry) / sizeof(__u64))
+
+#define BCH_JSET_ENTRY_TYPES() \
+ x(btree_keys, 0) \
+ x(btree_root, 1) \
+ x(prio_ptrs, 2) \
+ x(blacklist, 3) \
+ x(blacklist_v2, 4)
+
+enum {
+#define x(f, nr) BCH_JSET_ENTRY_##f = nr,
+ BCH_JSET_ENTRY_TYPES()
+#undef x
+ BCH_JSET_ENTRY_NR
+};
+
+/*
+ * 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.
+ */
+struct jset_entry_blacklist {
+ struct jset_entry entry;
+ __le64 seq;
+};
+
+struct jset_entry_blacklist_v2 {
+ struct jset_entry entry;
+ __le64 start;
+ __le64 end;
+};
+
+/*
+ * 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, aligned(8)));
+
+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
+
+/* 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") \
+ DEF_BTREE_ID(ALLOC, 4, "alloc") \
+ DEF_BTREE_ID(QUOTAS, 5, "quotas")
+
+#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, aligned(8)));
+
+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, aligned(8)));
+
+LE64_BITMASK(BTREE_NODE_ID, struct btree_node, flags, 0, 4);
+LE64_BITMASK(BTREE_NODE_LEVEL, struct btree_node, flags, 4, 8);
+/* 8-32 unused */
+LE64_BITMASK(BTREE_NODE_SEQ, struct btree_node, flags, 32, 64);
+
+struct btree_node_entry {
+ struct bch_csum csum;
+
+ union {
+ struct bset keys;
+ struct {
+ __u8 pad[22];
+ __le16 u64s;
+ __u64 _data[0];
+
+ };
+ };
+} __attribute__((packed, aligned(8)));
+
+#endif /* _BCACHEFS_FORMAT_H */
--
2.17.0