diff options
Diffstat (limited to 'include/linux/bcache.h')
| -rw-r--r-- | include/linux/bcache.h | 1284 |
1 files changed, 1284 insertions, 0 deletions
diff --git a/include/linux/bcache.h b/include/linux/bcache.h new file mode 100644 index 0000000..f09a44a --- /dev/null +++ b/include/linux/bcache.h @@ -0,0 +1,1284 @@ +#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 bkey { + __u64 _data[0]; + + /* 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]; + + __u32 version; + __u32 size; /* extent size, in sectors */ + struct bpos p; +#elif defined(__BIG_ENDIAN) + struct bpos p; + __u32 size; /* extent size, in sectors */ + __u32 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, + 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, version), \ + }, \ +}) + +/* bkey with inline value */ +struct bkey_i { + 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. + */ + +enum bch_extent_entry_type { + BCH_EXTENT_ENTRY_crc32 = 0, + BCH_EXTENT_ENTRY_ptr = 1, + BCH_EXTENT_ENTRY_crc64 = 2, +}; + +#define BCH_EXTENT_ENTRY_MAX 3 + +struct bch_extent_crc32 { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u32 type:1, + offset:7, + compressed_size:8, + uncompressed_size:8, + csum_type:4, + compression_type:4; + __u32 csum; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u32 csum; + __u32 compression_type:4, + csum_type:4, + uncompressed_size:8, + compressed_size:8, + offset:7, + type:1; +#endif +} __attribute__((packed, aligned(8))); + +#define CRC32_EXTENT_SIZE_MAX (1U << 7) + +/* 64k */ +#define BCH_COMPRESSED_EXTENT_MAX 128U + +struct bch_extent_crc64 { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u64 type:3, + offset:17, + compressed_size:18, + uncompressed_size:18, + csum_type:4, + compression_type:4; +#elif defined (__BIG_ENDIAN_BITFIELD) + __u64 compression_type:4, + csum_type:4, + uncompressed_size:18, + compressed_size:18, + offset:17, + type:3; +#endif + __u64 csum; +} __attribute__((packed, aligned(8))); + +#define CRC64_EXTENT_SIZE_MAX (1U << 17) + +/* + * @reservation - pointer hasn't been written to, just reserved + */ +struct bch_extent_ptr { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u64 type:2, + 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, + type:2; +#endif +} __attribute__((packed, aligned(8))); + +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_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); + +/* Maximum size (in u64s) a single pointer could be: */ +#define BKEY_EXTENT_PTR_U64s_MAX\ + ((sizeof(struct bch_extent_crc64) + \ + 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; + + __le16 i_mode; + __le16 pad; + __le32 i_flags; + + /* Nanoseconds */ + __le64 i_atime; + __le64 i_ctime; + __le64 i_mtime; + + __le64 i_size; + __le64 i_sectors; + + __le32 i_uid; + __le32 i_gid; + __le32 i_nlink; + + __le32 i_dev; + + __le64 i_hash_seed; +} __attribute__((packed)); +BKEY_VAL_TYPE(inode, BCH_INODE_FS); + +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 */ +}; + +LE32_BITMASK(INODE_STR_HASH_TYPE, struct bch_inode, i_flags, 28, 32); + +#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) + +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 + */ +#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 6 +#define BCACHE_SB_MAX_VERSION 6 + +#define SB_SECTOR 8 +#define SB_LABEL_SIZE 32 +#define MAX_CACHES_PER_SET 64 + +#define BDEV_DATA_START_DEFAULT 16 /* sectors */ + +struct cache_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 f1; + __le64 f2; +}; + +LE64_BITMASK(CACHE_STATE, struct cache_member, f1, 0, 4) +#define CACHE_ACTIVE 0U +#define CACHE_RO 1U +#define CACHE_FAILED 2U +#define CACHE_SPARE 3U +#define CACHE_STATE_NR 4U + +LE64_BITMASK(CACHE_TIER, struct cache_member, f1, 4, 8) +#define CACHE_TIERS 4U + +LE64_BITMASK(CACHE_REPLICATION_SET, struct cache_member, f1, 8, 16) + +LE64_BITMASK(CACHE_HAS_METADATA, struct cache_member, f1, 24, 25) +LE64_BITMASK(CACHE_HAS_DATA, struct cache_member, f1, 25, 26) + +LE64_BITMASK(CACHE_REPLACEMENT, struct cache_member, f1, 26, 30) +#define CACHE_REPLACEMENT_LRU 0U +#define CACHE_REPLACEMENT_FIFO 1U +#define CACHE_REPLACEMENT_RANDOM 2U +#define CACHE_REPLACEMENT_NR 3U + +LE64_BITMASK(CACHE_DISCARD, struct cache_member, f1, 30, 31); + +LE64_BITMASK(CACHE_NR_READ_ERRORS, struct cache_member, f2, 0, 20); +LE64_BITMASK(CACHE_NR_WRITE_ERRORS, struct cache_member, f2, 20, 40); + +struct cache_sb { + __le64 csum; + __le64 offset; /* sector where this sb was written */ + __le64 version; /* of on disk format */ + + uuid_le magic; /* bcache superblock UUID */ + + /* Identifies this disk within the cache set: */ + 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[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: + */ + uuid_le user_uuid; + + __le64 flags2; + __le64 pad1[5]; + + /* Number of cache_member entries: */ + __u8 nr_in_set; + + /* + * Index of this device - for PTR_DEV(), and also this device's + * slot in the cache_member array: + */ + __u8 nr_this_dev; + __le16 pad2[3]; + + __le16 block_size; /* sectors */ + __le16 pad3[6]; + + __le16 u64s; /* size of variable length portion */ + + union { + struct cache_member members[0]; + /* + * Journal buckets also in the variable length portion, after + * the member info: + */ + __le64 _data[0]; + }; +}; + +/* XXX: rename CACHE_SET -> BCH_FS or something? */ + +LE64_BITMASK(CACHE_SET_SYNC, struct cache_sb, flags, 0, 1); + +LE64_BITMASK(CACHE_SET_ERROR_ACTION, struct cache_sb, flags, 1, 4); +#define BCH_ON_ERROR_CONTINUE 0U +#define BCH_ON_ERROR_RO 1U +#define BCH_ON_ERROR_PANIC 2U +#define BCH_NR_ERROR_ACTIONS 3U + +LE64_BITMASK(CACHE_SET_META_REPLICAS_WANT,struct cache_sb, flags, 4, 8); +LE64_BITMASK(CACHE_SET_DATA_REPLICAS_WANT,struct cache_sb, flags, 8, 12); + +#define BCH_REPLICAS_MAX 4U + +LE64_BITMASK(CACHE_SB_CSUM_TYPE, struct cache_sb, flags, 12, 16); + +LE64_BITMASK(CACHE_SET_META_PREFERRED_CSUM_TYPE,struct cache_sb, flags, 16, 20); +#define BCH_CSUM_NONE 0U +#define BCH_CSUM_CRC32C 1U +#define BCH_CSUM_CRC64 2U +#define BCH_CSUM_NR 3U + +LE64_BITMASK(CACHE_SET_BTREE_NODE_SIZE, struct cache_sb, flags, 20, 36); + +LE64_BITMASK(CACHE_SET_META_REPLICAS_HAVE,struct cache_sb, flags, 36, 40); +LE64_BITMASK(CACHE_SET_DATA_REPLICAS_HAVE,struct cache_sb, flags, 40, 44); + +LE64_BITMASK(CACHE_SET_STR_HASH_TYPE,struct cache_sb, flags, 44, 48); +enum bch_str_hash_type { + BCH_STR_HASH_CRC32C = 0, + BCH_STR_HASH_CRC64 = 1, + BCH_STR_HASH_SIPHASH = 2, + BCH_STR_HASH_SHA1 = 3, +}; + +#define BCH_STR_HASH_NR 4 + +LE64_BITMASK(CACHE_SET_DATA_PREFERRED_CSUM_TYPE, struct cache_sb, flags, 48, 52); + +LE64_BITMASK(CACHE_SET_COMPRESSION_TYPE, struct cache_sb, flags, 52, 56); +enum { + BCH_COMPRESSION_NONE = 0, + BCH_COMPRESSION_LZ4 = 1, + BCH_COMPRESSION_GZIP = 2, +}; + +#define BCH_COMPRESSION_NR 3U + +/* Limit inode numbers to 32 bits: */ +LE64_BITMASK(CACHE_INODE_32BIT, struct cache_sb, flags, 56, 57); + +LE64_BITMASK(CACHE_SET_GC_RESERVE, struct cache_sb, flags, 57, 63); + +LE64_BITMASK(CACHE_SET_ROOT_RESERVE, struct cache_sb, flags2, 0, 6); + +/* + * Did we shut down cleanly? Just a hint, doesn't affect behaviour of + * mount/recovery path: + */ +LE64_BITMASK(CACHE_SET_CLEAN, struct cache_sb, flags2, 6, 7); + +LE64_BITMASK(CACHE_SET_JOURNAL_ENTRY_SIZE, struct cache_sb, flags2, 7, 15); + +/* options: */ + +/** + * CACHE_SET_OPT(name, choices, min, max, sb_option, sysfs_writeable) + * + * @name - name of mount option, sysfs attribute, and struct cache_set_opts + * member + * + * @choices - array of strings that the user can select from - option is by + * array index + * + * Booleans are special cased; if @choices is bch_bool_opt the mount + * options name and noname will work as expected. + * + * @min, @max + * + * @sb_option - name of corresponding superblock option + * + * @sysfs_writeable - if true, option will be modifiable at runtime via sysfs + */ + +#define CACHE_SET_SB_OPTS() \ + CACHE_SET_OPT(errors, \ + bch_error_actions, \ + 0, BCH_NR_ERROR_ACTIONS, \ + CACHE_SET_ERROR_ACTION, \ + true) \ + CACHE_SET_OPT(metadata_replicas, \ + bch_uint_opt, \ + 0, BCH_REPLICAS_MAX, \ + CACHE_SET_META_REPLICAS_WANT, \ + false) \ + CACHE_SET_OPT(data_replicas, \ + bch_uint_opt, \ + 0, BCH_REPLICAS_MAX, \ + CACHE_SET_DATA_REPLICAS_WANT, \ + false) \ + CACHE_SET_OPT(metadata_checksum, \ + bch_csum_types, \ + 0, BCH_CSUM_NR, \ + CACHE_SET_META_PREFERRED_CSUM_TYPE, \ + true) \ + CACHE_SET_OPT(data_checksum, \ + bch_csum_types, \ + 0, BCH_CSUM_NR, \ + CACHE_SET_DATA_PREFERRED_CSUM_TYPE, \ + true) \ + CACHE_SET_OPT(compression, \ + bch_compression_types, \ + 0, BCH_COMPRESSION_NR, \ + CACHE_SET_COMPRESSION_TYPE, \ + true) \ + CACHE_SET_OPT(str_hash, \ + bch_str_hash_types, \ + 0, BCH_STR_HASH_NR, \ + CACHE_SET_STR_HASH_TYPE, \ + true) \ + CACHE_SET_OPT(inodes_32bit, \ + bch_bool_opt, 0, 2, \ + CACHE_INODE_32BIT, \ + true) \ + CACHE_SET_OPT(gc_reserve_percent, \ + bch_uint_opt, \ + 5, 21, \ + CACHE_SET_GC_RESERVE, \ + false) \ + CACHE_SET_OPT(root_reserve_percent, \ + bch_uint_opt, \ + 0, 21, \ + CACHE_SET_ROOT_RESERVE, \ + false) + +/* 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; /* bcache 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[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 + +static inline unsigned bch_journal_buckets_offset(struct cache_sb *sb) +{ + return sb->nr_in_set * (sizeof(struct cache_member) / sizeof(__u64)); +} + +static inline unsigned bch_nr_journal_buckets(struct cache_sb *sb) +{ + return __le16_to_cpu(sb->u64s) - bch_journal_buckets_offset(sb); +} + +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 cache_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 BCACHE_SB_MAGIC 0xca451a4ef67385c6ULL +#define BCACHE_SB_MAGIC2 0x816dba487ff56582ULL +#define JSET_MAGIC 0x245235c1a3625032ULL +#define PSET_MAGIC 0x6750e15f87337f91ULL +#define BSET_MAGIC 0x90135c78b99e07f5ULL + +static inline __u64 jset_magic(struct cache_sb *sb) +{ + return __le64_to_cpu(sb->set_magic) ^ JSET_MAGIC; +} + +static inline __u64 pset_magic(struct cache_sb *sb) +{ + return __le64_to_cpu(sb->set_magic) ^ PSET_MAGIC; +} + +static inline __u64 bset_magic(struct cache_sb *sb) +{ + return __le64_to_cpu(sb->set_magic) ^ 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 { + __le64 csum; + __le64 magic; + __le32 version; + __le32 flags; + + /* Sequence number of oldest dirty journal entry */ + __le64 seq; + __le64 last_seq; + + __le16 read_clock; + __le16 write_clock; + __le32 u64s; /* size of d[] in u64s */ + + union { + struct jset_entry start[0]; + __u64 _data[0]; + }; +}; + +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 { + __le64 csum; + __le64 magic; + __le32 version; + __le32 flags; + + __le64 next_bucket; + + struct bucket_disk { + __le16 read_prio; + __le16 write_prio; + __u8 gen; + } __attribute__((packed)) data[]; +}; + +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); + +/* Only used in first bset */ +LE32_BITMASK(BSET_BTREE_LEVEL, struct bset, flags, 4, 8); + +LE32_BITMASK(BSET_BIG_ENDIAN, struct bset, flags, 8, 9); +LE32_BITMASK(BSET_SEPARATE_WHITEOUTS, + struct bset, flags, 9, 10); + +struct btree_node { + __le64 csum; + __le64 magic; + + /* Closed interval: */ + struct bpos min_key; + struct bpos max_key; + struct bkey_format format; + + struct bset keys; +} __attribute__((packed)); + +struct btree_node_entry { + __le64 csum; + struct bset keys; +} __attribute__((packed)); + +/* OBSOLETE */ + +#define 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 (k->field >> offset) & ~(~0ULL << (end - offset)); } \ + \ +static inline void SET_##name(type *k, __u64 v) \ +{ \ + k->field &= ~(~(~0ULL << (end - offset)) << offset); \ + k->field |= (v & ~(~0ULL << (end - offset))) << offset; \ +} + +struct bkey_v0 { + __u64 high; + __u64 low; + __u64 ptr[]; +}; + +#define KEY0_FIELD(name, field, offset, size) \ + BITMASK(name, struct bkey_v0, field, offset, size) + +KEY0_FIELD(KEY0_PTRS, high, 60, 63) +KEY0_FIELD(KEY0_CSUM, high, 56, 58) +KEY0_FIELD(KEY0_DIRTY, high, 36, 37) + +KEY0_FIELD(KEY0_SIZE, high, 20, 36) +KEY0_FIELD(KEY0_INODE, high, 0, 20) + +static inline unsigned long bkey_v0_u64s(const struct bkey_v0 *k) +{ + return (sizeof(struct bkey_v0) / sizeof(__u64)) + KEY0_PTRS(k); +} + +static inline struct bkey_v0 *bkey_v0_next(const struct bkey_v0 *k) +{ + __u64 *d = (__u64 *) k; + + return (struct bkey_v0 *) (d + bkey_v0_u64s(k)); +} + +struct jset_v0 { + __u64 csum; + __u64 magic; + __u64 seq; + __u32 version; + __u32 keys; + + __u64 last_seq; + + __BKEY_PADDED(uuid_bucket, 4); + __BKEY_PADDED(btree_root, 4); + __u16 btree_level; + __u16 pad[3]; + + __u64 prio_bucket[MAX_CACHES_PER_SET]; + + union { + struct bkey start[0]; + __u64 d[0]; + }; +}; + +/* UUIDS - per backing device/flash only volume metadata */ + +struct uuid_entry_v0 { + uuid_le uuid; + __u8 label[32]; + __u32 first_reg; + __u32 last_reg; + __u32 invalidated; + __u32 pad; +}; + +struct uuid_entry { + union { + struct { + uuid_le uuid; + __u8 label[32]; + __u32 first_reg; + __u32 last_reg; + __u32 invalidated; + + __u32 flags; + /* Size of flash only volumes */ + __u64 sectors; + }; + + __u8 pad[128]; + }; +}; + +BITMASK(UUID_FLASH_ONLY, struct uuid_entry, flags, 0, 1); + +#ifdef __cplusplus +} +#endif +#endif /* _LINUX_BCACHE_H */ + +/* vim: set foldnestmax=2: */ |