blob: fd40eb0818e4390073386c85e2e8faeceec779e4
1 | /* |
2 | * Copyright (C) 2013 Rolf Fokkens <rolf@fokkens.nl> |
3 | * |
4 | * This file may be redistributed under the terms of the |
5 | * GNU Lesser General Public License. |
6 | * |
7 | * Based on code fragments from bcache-tools by Kent Overstreet: |
8 | * http://evilpiepirate.org/git/bcache-tools.git |
9 | */ |
10 | |
11 | //kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_BCACHE) += bcache.o |
12 | |
13 | //config: |
14 | //config:config FEATURE_VOLUMEID_BCACHE |
15 | //config: bool "bcache filesystem" |
16 | //config: default y |
17 | //config: depends on VOLUMEID |
18 | //config: help |
19 | //config: TODO |
20 | //config: |
21 | |
22 | #include "volume_id_internal.h" |
23 | |
24 | #define SB_LABEL_SIZE 32 |
25 | #define SB_JOURNAL_BUCKETS 256U |
26 | |
27 | static const char bcache_magic[] ALIGN1 = { |
28 | 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca, |
29 | 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81 |
30 | }; |
31 | |
32 | struct bcache_super_block { |
33 | uint64_t csum; |
34 | uint64_t offset; /* sector where this sb was written */ |
35 | uint64_t version; |
36 | |
37 | uint8_t magic[16]; |
38 | |
39 | uint8_t uuid[16]; |
40 | union { |
41 | uint8_t set_uuid[16]; |
42 | uint64_t set_magic; |
43 | }; |
44 | uint8_t label[SB_LABEL_SIZE]; |
45 | |
46 | uint64_t flags; |
47 | uint64_t seq; |
48 | uint64_t pad[8]; |
49 | |
50 | union { |
51 | struct { |
52 | /* Cache devices */ |
53 | uint64_t nbuckets; /* device size */ |
54 | |
55 | uint16_t block_size; /* sectors */ |
56 | uint16_t bucket_size; /* sectors */ |
57 | |
58 | uint16_t nr_in_set; |
59 | uint16_t nr_this_dev; |
60 | }; |
61 | struct { |
62 | /* Backing devices */ |
63 | uint64_t data_offset; |
64 | |
65 | /* |
66 | * block_size from the cache device section is still used by |
67 | * backing devices, so don't add anything here until we fix |
68 | * things to not need it for backing devices anymore |
69 | */ |
70 | }; |
71 | }; |
72 | |
73 | uint32_t last_mount; /* time_t */ |
74 | |
75 | uint16_t first_bucket; |
76 | union { |
77 | uint16_t njournal_buckets; |
78 | uint16_t keys; |
79 | }; |
80 | uint64_t d[SB_JOURNAL_BUCKETS]; /* journal buckets */ |
81 | }; |
82 | |
83 | /* magic string */ |
84 | #define BCACHE_SB_MAGIC bcache_magic |
85 | /* magic string len */ |
86 | #define BCACHE_SB_MAGIC_LEN sizeof (bcache_magic) |
87 | /* super block offset */ |
88 | #define BCACHE_SB_OFF 0x1000 |
89 | /* supper block offset in kB */ |
90 | #define BCACHE_SB_KBOFF (BCACHE_SB_OFF >> 10) |
91 | /* magic string offset within super block */ |
92 | #define BCACHE_SB_MAGIC_OFF offsetof (struct bcache_super_block, magic) |
93 | |
94 | int FAST_FUNC volume_id_probe_bcache(struct volume_id *id /*,uint64_t off*/) |
95 | { |
96 | struct bcache_super_block *sb; |
97 | |
98 | sb = volume_id_get_buffer(id, BCACHE_SB_OFF, sizeof(*sb)); |
99 | if (sb == NULL) |
100 | return -1; |
101 | |
102 | if (memcmp(sb->magic, BCACHE_SB_MAGIC, BCACHE_SB_MAGIC_LEN) != 0) |
103 | return -1; |
104 | |
105 | volume_id_set_label_string(id, sb->label, SB_LABEL_SIZE); |
106 | volume_id_set_uuid(id, sb->uuid, UUID_DCE); |
107 | IF_FEATURE_BLKID_TYPE(id->type = "bcache";) |
108 | |
109 | return 0; |
110 | } |
111 |