blob: c83f8382b5e354de9f0e9f1e8d5c9405840dfe66 [file] [log] [blame]
/*
* Author: Kent Overstreet <kmo@daterainc.com>
*
* GPLv2
*/
#ifndef _BCACHE_H
#define _BCACHE_H
#define BITMASK(name, type, field, offset, size) \
static inline uint64_t name(const type *k) \
{ return (k->field >> offset) & ~(((uint64_t) ~0) << size); } \
\
static inline void SET_##name(type *k, uint64_t v) \
{ \
k->field &= ~(~((uint64_t) ~0 << size) << offset); \
k->field |= v << offset; \
}
static const char bcache_magic[] = {
0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81 };
/*
* 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
*/
#define BCACHE_SB_VERSION_CDEV 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_MAX_VERSION 4
#define SB_SECTOR 8
#define SB_LABEL_SIZE 32
#define SB_JOURNAL_BUCKETS 256U
#define BDEV_DATA_START_DEFAULT 16 /* sectors */
#define SB_START (SB_SECTOR * 512)
struct cache_sb {
uint64_t csum;
uint64_t offset; /* sector where this sb was written */
uint64_t version;
uint8_t magic[16];
uint8_t uuid[16];
union {
uint8_t set_uuid[16];
uint64_t set_magic;
};
uint8_t label[SB_LABEL_SIZE];
uint64_t flags;
uint64_t seq;
uint64_t pad[8];
union {
struct {
/* Cache devices */
uint64_t nbuckets; /* device size */
uint16_t block_size; /* sectors */
uint16_t bucket_size; /* sectors */
uint16_t nr_in_set;
uint16_t nr_this_dev;
};
struct {
/* Backing devices */
uint64_t data_offset;
/*
* block_size from the cache device section is still used by
* backing devices, so don't add anything here until we fix
* things to not need it for backing devices anymore
*/
};
};
uint32_t last_mount; /* time_t */
uint16_t first_bucket;
union {
uint16_t njournal_buckets;
uint16_t keys;
};
uint64_t d[SB_JOURNAL_BUCKETS]; /* journal buckets */
};
static inline bool SB_IS_BDEV(const struct cache_sb *sb)
{
return sb->version == BCACHE_SB_VERSION_BDEV
|| sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET;
}
BITMASK(CACHE_SYNC, struct cache_sb, flags, 0, 1);
BITMASK(CACHE_DISCARD, struct cache_sb, flags, 1, 1);
BITMASK(CACHE_REPLACEMENT, struct cache_sb, flags, 2, 3);
#define CACHE_REPLACEMENT_LRU 0U
#define CACHE_REPLACEMENT_FIFO 1U
#define CACHE_REPLACEMENT_RANDOM 2U
BITMASK(BDEV_CACHE_MODE, struct cache_sb, flags, 0, 4);
#define CACHE_MODE_WRITETHROUGH 0U
#define CACHE_MODE_WRITEBACK 1U
#define CACHE_MODE_WRITEAROUND 2U
#define CACHE_MODE_NONE 3U
BITMASK(BDEV_STATE, struct cache_sb, flags, 61, 2);
#define BDEV_STATE_NONE 0U
#define BDEV_STATE_CLEAN 1U
#define BDEV_STATE_DIRTY 2U
#define BDEV_STATE_STALE 3U
uint64_t crc64(const void *data, size_t len);
#define node(i, j) ((void *) ((i)->d + (j)))
#define end(i) node(i, (i)->keys)
#define csum_set(i) \
crc64(((void *) (i)) + 8, ((void *) end(i)) - (((void *) (i)) + 8))
#endif