106 lines
2.4 KiB
C
106 lines
2.4 KiB
C
/*
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* Copyright (C) 2013 Rolf Fokkens <rolf@fokkens.nl>
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*
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* This file may be redistributed under the terms of the
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* GNU Lesser General Public License.
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*
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* Based on code fragments from bcache-tools by Kent Overstreet:
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* http://evilpiepirate.org/git/bcache-tools.git
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*/
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//config:config FEATURE_VOLUMEID_BCACHE
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//config: bool "bcache filesystem"
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//config: default y
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//config: depends on VOLUMEID
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//kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_BCACHE) += bcache.o
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#include "volume_id_internal.h"
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#define SB_LABEL_SIZE 32
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#define SB_JOURNAL_BUCKETS 256U
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static const char bcache_magic[] ALIGN1 = {
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0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
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0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
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};
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struct bcache_super_block {
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uint64_t csum;
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uint64_t offset; /* sector where this sb was written */
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uint64_t version;
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uint8_t magic[16];
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uint8_t uuid[16];
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union {
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uint8_t set_uuid[16];
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uint64_t set_magic;
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};
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uint8_t label[SB_LABEL_SIZE];
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uint64_t flags;
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uint64_t seq;
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uint64_t pad[8];
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union {
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struct {
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/* Cache devices */
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uint64_t nbuckets; /* device size */
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uint16_t block_size; /* sectors */
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uint16_t bucket_size; /* sectors */
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uint16_t nr_in_set;
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uint16_t nr_this_dev;
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};
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struct {
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/* Backing devices */
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uint64_t data_offset;
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/*
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* block_size from the cache device section is still used by
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* backing devices, so don't add anything here until we fix
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* things to not need it for backing devices anymore
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*/
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};
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};
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uint32_t last_mount; /* time_t */
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uint16_t first_bucket;
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union {
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uint16_t njournal_buckets;
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uint16_t keys;
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};
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uint64_t d[SB_JOURNAL_BUCKETS]; /* journal buckets */
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};
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/* magic string */
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#define BCACHE_SB_MAGIC bcache_magic
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/* magic string len */
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#define BCACHE_SB_MAGIC_LEN sizeof (bcache_magic)
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/* super block offset */
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#define BCACHE_SB_OFF 0x1000
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/* supper block offset in kB */
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#define BCACHE_SB_KBOFF (BCACHE_SB_OFF >> 10)
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/* magic string offset within super block */
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#define BCACHE_SB_MAGIC_OFF offsetof (struct bcache_super_block, magic)
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int FAST_FUNC volume_id_probe_bcache(struct volume_id *id /*,uint64_t off*/)
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{
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struct bcache_super_block *sb;
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sb = volume_id_get_buffer(id, BCACHE_SB_OFF, sizeof(*sb));
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if (sb == NULL)
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return -1;
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if (memcmp(sb->magic, BCACHE_SB_MAGIC, BCACHE_SB_MAGIC_LEN) != 0)
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return -1;
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volume_id_set_label_string(id, sb->label, SB_LABEL_SIZE);
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volume_id_set_uuid(id, sb->uuid, UUID_DCE);
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IF_FEATURE_BLKID_TYPE(id->type = "bcache";)
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return 0;
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}
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