mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-23 19:11:51 +00:00
Code Issues Releases Wiki Activity
linux-stable/fs/bcachefs/bcachefs_format.h
Kent Overstreet a50ed7c8e8 bcachefs: BCH_SB_RESERVE_BYTES 
Add an option, gc_reserve_bytes, to set the copygc reserve as a size
instead of a percent

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:08 -04:00

1499 lines
39 KiB
C
Raw Blame History

/* 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/uuid.h>
#ifdef __KERNEL__
typedef uuid_t __uuid_t;
#endif
#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 - 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
} __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 __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
__u64 lo;
__u32 hi;
#elif __BYTE_ORDER__ == __ORDER_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 __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
} __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 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 const unsigned bch_crc_bytes[] = {
[BCH_CSUM_NONE] = 0,
[BCH_CSUM_CRC32C_NONZERO] = 4,
[BCH_CSUM_CRC32C] = 4,
[BCH_CSUM_CRC64_NONZERO] = 8,
[BCH_CSUM_CRC64] = 8,
[BCH_CSUM_CHACHA20_POLY1305_80] = 10,
[BCH_CSUM_CHACHA20_POLY1305_128] = 16,
};
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:13,
offset:13,
_uncompressed_size:13,
_compressed_size:13,
type:4;
#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 __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
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;
__u64 _data[0];
union bch_extent_entry start[];
} __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,
__BCH_INODE_UNLINKED = 7,
/* 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_UNLINKED (1 << __BCH_INODE_UNLINKED)
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_t 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);
#define BCH_NAME_MAX (U8_MAX * sizeof(u64) - \
sizeof(struct bkey) - \
offsetof(struct bch_dirent, d_name))
/* 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) \
x(clean, 6)
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_t 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[];
};
struct bch_sb_field_replicas {
struct bch_sb_field field;
struct bch_replicas_entry entries[];
};
/* 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];
};
/*
* On clean shutdown, store btree roots and current journal sequence number in
* the superblock:
*/
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];
};
};
struct bch_sb_field_clean {
struct bch_sb_field field;
__le32 flags;
__le16 read_clock;
__le16 write_clock;
__le64 journal_seq;
union {
struct jset_entry start[0];
__u64 _data[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_t 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;
__le16 version;
__le16 version_min;
__le16 pad[2];
__uuid_t magic;
__uuid_t uuid;
__uuid_t 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);
LE64_BITMASK(BCH_SB_GC_RESERVE_BYTES, struct bch_sb, flags[2], 4, 64);
/* Features: */
enum bch_sb_features {
BCH_FEATURE_LZ4 = 0,
BCH_FEATURE_GZIP = 1,
BCH_FEATURE_ZSTD = 2,
BCH_FEATURE_ATOMIC_NLINK = 3,
};
/* 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_INIT(0xc68573f6, 0x4e1a, 0x45ca, \
0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81)
#define BCHFS_MAGIC \
UUID_INIT(0xc68573f6, 0x66ce, 0x90a9, \
0xd9, 0x6a, 0x60, 0xcf, 0x80, 0x3d, 0xf7, 0xef)
#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
#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 */
Reference in a new issue View git blame Copy permalink