diff options
Diffstat (limited to 'bcache.h')
| -rw-r--r-- | bcache.h | 52 |
1 files changed, 37 insertions, 15 deletions
@@ -15,24 +15,27 @@ static const char bcache_magic[] = { 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca, 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81 }; -/* Version 1: Backing dev +/* + * Version 0: Cache device + * Version 1: Backing device * Version 2: Seed pointer into btree node checksum - * Version 3: Backing dev superblock has offset of start of data + * Version 3: Cache device with new UUID format + * Version 4: Backing device with data offset */ - -#define BCACHE_SB_BDEV_VERSION 3 -#define BCACHE_SB_MAX_VERSION 3 +#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 BDEV_DATA_START 16 /* sectors */ - +#define BDEV_DATA_START_DEFAULT 16 /* sectors */ struct cache_sb { uint64_t csum; uint64_t offset; /* sector where this sb was written */ uint64_t version; -#define CACHE_BACKING_DEV 1 uint8_t magic[16]; @@ -47,18 +50,37 @@ struct cache_sb { uint64_t seq; uint64_t pad[8]; - uint64_t nbuckets; /* device size */ - uint16_t block_size; /* sectors */ - uint16_t bucket_size; /* sectors */ + union { + struct { + /* Cache devices */ + uint64_t nbuckets; /* device size */ - uint16_t nr_in_set; - uint16_t nr_this_dev; + 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; - uint16_t keys; /* number of journal buckets */ - uint64_t d[]; /* journal buckets */ + union { + uint16_t njournal_buckets; + uint16_t keys; + }; + uint64_t d[]; /* journal buckets */ }; BITMASK(SB_BDEV, struct cache_sb, version, 0, 1); |