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#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <uuid/uuid.h>
#include "ccan/ilog/ilog.h"
#include "bcache-ondisk.h"
#include "libbcache.h"
#include "crypto.h"
#define BCH_MIN_NR_NBUCKETS (1 << 10)
/* first bucket should start 1 mb in, in sectors: */
#define FIRST_BUCKET_OFFSET (1 << 11)
void __do_write_sb(int fd, void *sb, size_t bytes)
{
char zeroes[SB_SECTOR << 9] = {0};
/* Zero start of disk */
if (pwrite(fd, zeroes, SB_SECTOR << 9, 0) != SB_SECTOR << 9) {
perror("write error trying to zero start of disk\n");
exit(EXIT_FAILURE);
}
/* Write superblock */
if (pwrite(fd, sb, bytes, SB_SECTOR << 9) != bytes) {
perror("write error trying to write superblock\n");
exit(EXIT_FAILURE);
}
fsync(fd);
close(fd);
}
#define do_write_sb(_fd, _sb) \
__do_write_sb(_fd, _sb, ((void *) __bset_bkey_last(_sb)) - (void *) _sb);
/* minimum size filesystem we can create, given a bucket size: */
static u64 min_size(unsigned bucket_size)
{
return (DIV_ROUND_UP(FIRST_BUCKET_OFFSET, bucket_size) +
BCH_MIN_NR_NBUCKETS) * bucket_size;
}
void bcache_format(struct dev_opts *devs, size_t nr_devs,
unsigned block_size,
unsigned btree_node_size,
unsigned meta_csum_type,
unsigned data_csum_type,
unsigned compression_type,
const char *passphrase,
unsigned meta_replicas,
unsigned data_replicas,
unsigned on_error_action,
char *label,
uuid_le uuid)
{
struct cache_sb *sb;
struct dev_opts *i;
/* calculate block size: */
if (!block_size)
for (i = devs; i < devs + nr_devs; i++)
block_size = max(block_size,
get_blocksize(i->path, i->fd));
/* calculate bucket sizes: */
for (i = devs; i < devs + nr_devs; i++) {
if (!i->size)
i->size = get_size(i->path, i->fd);
if (!i->bucket_size) {
if (i->size < min_size(block_size))
die("cannot format %s, too small (%llu sectors, min %llu)",
i->path, i->size, min_size(block_size));
/* Want a bucket size of at least 128k, if possible: */
i->bucket_size = max(block_size, 256U);
if (i->size >= min_size(i->bucket_size)) {
unsigned scale = max(1U,
ilog2(i->size / min_size(i->bucket_size)) / 4);
scale = rounddown_pow_of_two(scale);
/* max bucket size 1 mb */
i->bucket_size = min(i->bucket_size * scale, 1U << 11);
} else {
do {
i->bucket_size /= 2;
} while (i->size < min_size(i->bucket_size));
}
}
/* first bucket: 1 mb in */
i->first_bucket = DIV_ROUND_UP(FIRST_BUCKET_OFFSET, i->bucket_size);
i->nbuckets = i->size / i->bucket_size;
if (i->bucket_size < block_size)
die("Bucket size cannot be smaller than block size");
if (i->nbuckets - i->first_bucket < BCH_MIN_NR_NBUCKETS)
die("Not enough buckets: %llu, need %u (bucket size %u)",
i->nbuckets - i->first_bucket, BCH_MIN_NR_NBUCKETS,
i->bucket_size);
}
/* calculate btree node size: */
if (!btree_node_size) {
/* 256k default btree node size */
btree_node_size = 512;
for (i = devs; i < devs + nr_devs; i++)
btree_node_size = min(btree_node_size, i->bucket_size);
}
sb = calloc(1, sizeof(*sb) + sizeof(struct cache_member) * nr_devs);
sb->offset = __cpu_to_le64(SB_SECTOR);
sb->version = __cpu_to_le64(BCACHE_SB_VERSION_CDEV_V3);
sb->magic = BCACHE_MAGIC;
sb->block_size = __cpu_to_le16(block_size);
sb->user_uuid = uuid;
sb->nr_in_set = nr_devs;
uuid_generate(sb->set_uuid.b);
if (label)
strncpy((char *) sb->label, label, sizeof(sb->label));
/*
* don't have a userspace crc32c implementation handy, just always use
* crc64
*/
SET_CACHE_SB_CSUM_TYPE(sb, BCH_CSUM_CRC64);
SET_CACHE_SET_META_CSUM_TYPE(sb, meta_csum_type);
SET_CACHE_SET_DATA_CSUM_TYPE(sb, data_csum_type);
SET_CACHE_SET_COMPRESSION_TYPE(sb, compression_type);
SET_CACHE_SET_BTREE_NODE_SIZE(sb, btree_node_size);
SET_CACHE_SET_META_REPLICAS_WANT(sb, meta_replicas);
SET_CACHE_SET_META_REPLICAS_HAVE(sb, meta_replicas);
SET_CACHE_SET_DATA_REPLICAS_WANT(sb, data_replicas);
SET_CACHE_SET_DATA_REPLICAS_HAVE(sb, data_replicas);
SET_CACHE_SET_ERROR_ACTION(sb, on_error_action);
SET_CACHE_SET_STR_HASH_TYPE(sb, BCH_STR_HASH_SIPHASH);
if (passphrase) {
struct bcache_key key;
struct bcache_disk_key disk_key;
derive_passphrase(&key, passphrase);
disk_key_init(&disk_key);
disk_key_encrypt(sb, &disk_key, &key);
memcpy(sb->encryption_key, &disk_key, sizeof(disk_key));
SET_CACHE_SET_ENCRYPTION_TYPE(sb, 1);
SET_CACHE_SET_ENCRYPTION_KEY(sb, 1);
memzero_explicit(&disk_key, sizeof(disk_key));
memzero_explicit(&key, sizeof(key));
}
for (i = devs; i < devs + nr_devs; i++) {
struct cache_member *m = sb->members + (i - devs);
uuid_generate(m->uuid.b);
m->nbuckets = __cpu_to_le64(i->nbuckets);
m->first_bucket = __cpu_to_le16(i->first_bucket);
m->bucket_size = __cpu_to_le16(i->bucket_size);
SET_CACHE_TIER(m, i->tier);
SET_CACHE_REPLACEMENT(m, CACHE_REPLACEMENT_LRU);
SET_CACHE_DISCARD(m, i->discard);
}
sb->u64s = __cpu_to_le16(bch_journal_buckets_offset(sb));
for (i = devs; i < devs + nr_devs; i++) {
struct cache_member *m = sb->members + (i - devs);
char uuid_str[40], set_uuid_str[40];
sb->disk_uuid = m->uuid;
sb->nr_this_dev = i - devs;
sb->csum = __cpu_to_le64(__csum_set(sb, __le16_to_cpu(sb->u64s),
CACHE_SB_CSUM_TYPE(sb)));
uuid_unparse(sb->disk_uuid.b, uuid_str);
uuid_unparse(sb->user_uuid.b, set_uuid_str);
printf("UUID: %s\n"
"Set UUID: %s\n"
"version: %u\n"
"nbuckets: %llu\n"
"block_size: %u\n"
"bucket_size: %u\n"
"nr_in_set: %u\n"
"nr_this_dev: %u\n"
"first_bucket: %u\n",
uuid_str, set_uuid_str,
(unsigned) sb->version,
__le64_to_cpu(m->nbuckets),
__le16_to_cpu(sb->block_size),
__le16_to_cpu(m->bucket_size),
sb->nr_in_set,
sb->nr_this_dev,
__le16_to_cpu(m->first_bucket));
do_write_sb(i->fd, sb);
}
free(sb);
}
void bcache_super_read(const char *path, struct cache_sb *sb)
{
int fd = open(path, O_RDONLY);
if (fd < 0)
die("couldn't open %s", path);
if (pread(fd, sb, sizeof(*sb), SB_SECTOR << 9) != sizeof(*sb))
die("error reading superblock");
if (memcmp(&sb->magic, &BCACHE_MAGIC, sizeof(sb->magic)))
die("not a bcache superblock");
}
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