summaryrefslogtreecommitdiff
path: root/make-bcache.c
blob: 2c311476b2344c79d41cb46c263ae1215ffff1c2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
#define _FILE_OFFSET_BITS	64
#define __USE_FILE_OFFSET64
#define _XOPEN_SOURCE 600

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <linux/fs.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <uuid/uuid.h>

#include "bcache.h"

uint64_t getblocks(int fd)
{
	uint64_t ret;
	struct stat statbuf;
	if (fstat(fd, &statbuf)) {
		perror("stat error\n");
		exit(EXIT_FAILURE);
	}
	ret = statbuf.st_size / 512;
	if (S_ISBLK(statbuf.st_mode))
		if (ioctl(fd, BLKGETSIZE, &ret)) {
			perror("ioctl error");
			exit(EXIT_FAILURE);
		}
	return ret;
}

uint64_t hatoi(const char *s)
{
	char *e;
	long long i = strtoll(s, &e, 10);
	switch (*e) {
		case 't':
		case 'T':
			i *= 1024;
		case 'g':
		case 'G':
			i *= 1024;
		case 'm':
		case 'M':
			i *= 1024;
		case 'k':
		case 'K':
			i *= 1024;
	}
	return i;
}

void usage()
{
	printf("Usage: make-bcache [options] device\n"
	       "	-C, --cache		Format a cache device\n"
	       "	-B, --bdev		Format a backing device\n"
	       "	-b, --bucket		bucket size\n"
	       "	-w, --block		block size (hard sector size of SSD, often 2k)\n"
	       "	-U			UUID\n"
	       "	    --writeback		enable writeback\n"
	       "	-h, --help		display this help and exit\n");
	exit(EXIT_FAILURE);
}

int writeback;

struct option opts[] = {
	{ "cache",	0, NULL,	'C' },
	{ "bdev",	0, NULL,	'B' },
	{ "bucket",	1, NULL,	'b' },
	{ "block",	1, NULL,	'w' },
	{ "writeback",	0, &writeback,	1 },
	{ "help",	0, NULL,	'h' },
	{ NULL,		0, NULL,	0 },
};

void write_sb(char *dev, struct cache_sb *sb)
{
	int fd;
	char uuid[40], set_uuid[40];

	if (sb->version > 1) {
		printf("Must specify one of -C or -B\n");
		usage();
	}

	if ((sb->bucket_size & (sb->bucket_size - 1)) ||
	    (sb->block_size  & (sb->block_size - 1))) {
		printf("Block and bucket sizes must be powers of two\n");
		exit(EXIT_FAILURE);
	}

	if (sb->bucket_size < sb->block_size) {
		printf("Bad bucket size %i\n", sb->bucket_size);
		exit(EXIT_FAILURE);
	}

	if ((fd = open(dev, O_RDWR)) == -1) {
		printf("Can't open dev %s: %s\n", dev, strerror(errno));
		exit(EXIT_FAILURE);
	}

	if (sb->version == CACHE_BACKING_DEV &&
	    writeback)
		SET_BDEV_WRITEBACK(sb, 1);
	else
		SET_BDEV_WRITEBACK(sb, 0);

	sb->offset		= SB_SECTOR;
	memcpy(sb->magic, bcache_magic, 16);
	sb->nbuckets		= getblocks(fd) / sb->bucket_size;
	sb->nr_in_set		= 1;
	sb->first_bucket	= (23 / sb->bucket_size) + 1;
	uuid_unparse(sb->uuid, uuid);
	uuid_unparse(sb->set_uuid, set_uuid);
	sb->csum = csum_set(sb);

	if (sb->nbuckets < 1 << 7) {
		printf("Not enough buckets: %ju, need %u\n",
		       sb->nbuckets, 1 << 7);
		exit(EXIT_FAILURE);
	}

	printf("UUID:			%s\n"
	       "Set UUID:		%s\n"
	       "nbuckets:		%ju\n"
	       "block_size:		%u\n"
	       "bucket_size:		%u\n"
	       "nr_in_set:		%u\n"
	       "nr_this_dev:		%u\n"
	       "first_bucket:		%u\n",
	       uuid, set_uuid,
	       sb->nbuckets,
	       sb->block_size,
	       sb->bucket_size,
	       sb->nr_in_set,
	       sb->nr_this_dev,
	       sb->first_bucket);

	if (pwrite(fd, sb, sizeof(*sb), SB_SECTOR << 9) != sizeof(*sb)) {
		perror("write error\n");
		exit(EXIT_FAILURE);
	}

	fsync(fd);
	close(fd);

	uuid_generate(sb->uuid);
}

int main(int argc, char **argv)
{
	bool written = false;
	int c;
	struct cache_sb sb;

	memset(&sb, 0, sizeof(struct cache_sb));
	sb.version = 2;
	sb.block_size = 8;
	sb.bucket_size = 1024;

	uuid_generate(sb.uuid);
	uuid_generate(sb.set_uuid);

	while ((c = getopt_long(argc, argv,
				"-hCBU:w:b:",
				opts, NULL)) != -1)
		switch (c) {
		case 'C':
			sb.version = 0;
			break;
		case 'B':
			sb.version = CACHE_BACKING_DEV;
			break;
		case 'b':
			sb.bucket_size = hatoi(optarg) / 512;
			break;
		case 'w':
			sb.block_size = hatoi(optarg) / 512;
			break;
		case 'U':
			if (uuid_parse(optarg, sb.uuid)) {
				printf("Bad uuid\n");
				exit(EXIT_FAILURE);
			}
			break;
		case 'h':
			usage();
			break;
		case 1:
			write_sb(optarg, &sb);
			written = true;
			break;
		}

	if (!written) {
		printf("Please supply a device\n");
		usage();
	}

	return 0;
}