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#define _FILE_OFFSET_BITS 64
#define __USE_FILE_OFFSET64
#define _XOPEN_SOURCE 500
#include <errno.h>
#include <fcntl.h>
#include <inttypes.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"
static void usage()
{
fprintf(stderr, "Usage: bcache-super-show [-f] <device>\n");
}
int main(int argc, char **argv)
{
bool force_csum = false;
int o;
extern char *optarg;
struct cache_sb sb;
char uuid[40];
uint64_t expected_csum;
while ((o = getopt(argc, argv, "f")) != EOF)
switch (o) {
case 'f':
force_csum = 1;
break;
default:
usage();
exit(1);
}
argv += optind;
argc -= optind;
if (argc != 1) {
usage();
exit(1);
}
int fd = open(argv[0], O_RDONLY);
if (fd < 0) {
printf("Can't open dev %s: %s\n", argv[0], strerror(errno));
exit(2);
}
if (pread(fd, &sb, sizeof(sb), SB_START) != sizeof(sb)) {
fprintf(stderr, "Couldn't read\n");
exit(2);
}
printf("sb.magic\t\t");
if (!memcmp(sb.magic, bcache_magic, 16)) {
printf("ok\n");
} else {
printf("bad magic\n");
fprintf(stderr, "Invalid superblock (bad magic)\n");
exit(2);
}
printf("sb.first_sector\t\t%" PRIu64, sb.offset);
if (sb.offset == SB_SECTOR) {
printf(" [match]\n");
} else {
printf(" [expected %ds]\n", SB_SECTOR);
fprintf(stderr, "Invalid superblock (bad sector)\n");
exit(2);
}
printf("sb.csum\t\t\t%" PRIX64, sb.csum);
expected_csum = csum_set(&sb);
if (sb.csum == expected_csum) {
printf(" [match]\n");
} else {
printf(" [expected %" PRIX64 "]\n", expected_csum);
if (!force_csum) {
fprintf(stderr, "Corrupt superblock (bad csum)\n");
exit(2);
}
}
printf("sb.version\t\t%" PRIu64, sb.version);
switch (sb.version) {
// These are handled the same by the kernel
case BCACHE_SB_VERSION_CDEV:
case BCACHE_SB_VERSION_CDEV_WITH_UUID:
printf(" [cache device]\n");
break;
// The second adds data offset support
case BCACHE_SB_VERSION_BDEV:
case BCACHE_SB_VERSION_BDEV_WITH_OFFSET:
printf(" [backing device]\n");
break;
default:
printf(" [unknown]\n");
// exit code?
return 0;
}
putchar('\n');
uuid_unparse(sb.uuid, uuid);
printf("dev.uuid\t\t%s\n", uuid);
printf("dev.sectors_per_block\t%u\n"
"dev.sectors_per_bucket\t%u\n"
"dev.bucket_count\t%ju\n"
"dev.cache_count\t\t%u\n", // expect SB_IS_BDEV(&sb) ? 0 : 1
sb.block_size,
sb.bucket_size,
sb.nbuckets,
sb.nr_this_dev);
if (!SB_IS_BDEV(&sb)) {
printf("dev.cache.first_bucket\t%u\n"
"dev.cache.first_sector\t%u\n"
"dev.cache.discard\t%s\n",
sb.first_bucket,
sb.bucket_size * sb.first_bucket,
CACHE_DISCARD(&sb) ? "yes" : "no");
} else if (sb.version == BCACHE_SB_VERSION_BDEV) {
printf("dev.data.first_sector\t%u\n"
"dev.data.writeback\t%s\n",
BDEV_DATA_START_DEFAULT,
BDEV_WRITEBACK(&sb) ? "yes" : "no");
} else if (sb.version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET) {
if (sb.keys == 1 || sb.d[0]) {
fprintf(stderr, "Possible experimental format detected, bailing\n");
exit(3);
}
printf("dev.data.first_sector\t%lu\n"
"dev.data.writeback\t%s\n",
sb.data_offset,
BDEV_WRITEBACK(&sb) ? "yes" : "no");
}
putchar('\n');
uuid_unparse(sb.set_uuid, uuid);
printf("cset.uuid\t\t%s\n", uuid);
printf("cset.cache_count\t%u\n\n", sb.nr_in_set);
return 0;
}
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