/* * 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 */ //kbuild:lib-$(CONFIG_FEATURE_VOLUMEID_BCACHE) += bcache.o //config:config FEATURE_VOLUMEID_BCACHE //config: bool "bcache filesystem" //config: default y //config: depends on VOLUMEID #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; }