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