2 * Copyright (C) 2013 Rolf Fokkens <rolf@fokkens.nl>
4 * This file may be redistributed under the terms of the
5 * GNU Lesser General Public License.
7 * Based on code fragments from bcache-tools by Kent Overstreet:
8 * http://evilpiepirate.org/git/bcache-tools.git
11 //kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_BCACHE) += bcache.o
13 //config:config FEATURE_VOLUMEID_BCACHE
14 //config: bool "bcache filesystem"
16 //config: depends on VOLUMEID
18 #include "volume_id_internal.h"
20 #define SB_LABEL_SIZE 32
21 #define SB_JOURNAL_BUCKETS 256U
23 static const char bcache_magic[] ALIGN1 = {
24 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
25 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
28 struct bcache_super_block {
30 uint64_t offset; /* sector where this sb was written */
40 uint8_t label[SB_LABEL_SIZE];
49 uint64_t nbuckets; /* device size */
51 uint16_t block_size; /* sectors */
52 uint16_t bucket_size; /* sectors */
62 * block_size from the cache device section is still used by
63 * backing devices, so don't add anything here until we fix
64 * things to not need it for backing devices anymore
69 uint32_t last_mount; /* time_t */
71 uint16_t first_bucket;
73 uint16_t njournal_buckets;
76 uint64_t d[SB_JOURNAL_BUCKETS]; /* journal buckets */
80 #define BCACHE_SB_MAGIC bcache_magic
81 /* magic string len */
82 #define BCACHE_SB_MAGIC_LEN sizeof (bcache_magic)
83 /* super block offset */
84 #define BCACHE_SB_OFF 0x1000
85 /* supper block offset in kB */
86 #define BCACHE_SB_KBOFF (BCACHE_SB_OFF >> 10)
87 /* magic string offset within super block */
88 #define BCACHE_SB_MAGIC_OFF offsetof (struct bcache_super_block, magic)
90 int FAST_FUNC volume_id_probe_bcache(struct volume_id *id /*,uint64_t off*/)
92 struct bcache_super_block *sb;
94 sb = volume_id_get_buffer(id, BCACHE_SB_OFF, sizeof(*sb));
98 if (memcmp(sb->magic, BCACHE_SB_MAGIC, BCACHE_SB_MAGIC_LEN) != 0)
101 volume_id_set_label_string(id, sb->label, SB_LABEL_SIZE);
102 volume_id_set_uuid(id, sb->uuid, UUID_DCE);
103 IF_FEATURE_BLKID_TYPE(id->type = "bcache";)