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/*
* Copyright (C) 2013 Rolf Fokkens <rolf@fokkens.nl>
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*
* Based on code fragments from bcache-tools by Kent Overstreet:
* http://evilpiepirate.org/git/bcache-tools.git
*/
//config:config FEATURE_VOLUMEID_BCACHE
//config: bool "bcache filesystem"
//config: default y
//config: depends on VOLUMEID
//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_BCACHE) += bcache.o
#include "volume_id_internal.h"
#define SB_LABEL_SIZE 32
#define SB_JOURNAL_BUCKETS 256U
static const char bcache_magic[] ALIGN1 = {
0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
};
struct bcache_super_block {
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 */
};
/* magic string */
#define BCACHE_SB_MAGIC bcache_magic
/* magic string len */
#define BCACHE_SB_MAGIC_LEN sizeof (bcache_magic)
/* super block offset */
#define BCACHE_SB_OFF 0x1000
/* supper block offset in kB */
#define BCACHE_SB_KBOFF (BCACHE_SB_OFF >> 10)
/* magic string offset within super block */
#define BCACHE_SB_MAGIC_OFF offsetof (struct bcache_super_block, magic)
int FAST_FUNC volume_id_probe_bcache(struct volume_id *id /*,uint64_t off*/)
{
struct bcache_super_block *sb;
sb = volume_id_get_buffer(id, BCACHE_SB_OFF, sizeof(*sb));
if (sb == NULL)
return -1;
if (memcmp(sb->magic, BCACHE_SB_MAGIC, BCACHE_SB_MAGIC_LEN) != 0)
return -1;
volume_id_set_label_string(id, sb->label, SB_LABEL_SIZE);
volume_id_set_uuid(id, sb->uuid, UUID_DCE);
IF_FEATURE_BLKID_TYPE(id->type = "bcache";)
return 0;
}
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