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-rw-r--r--bcache-test.c127
-rw-r--r--make-bcache.c108
2 files changed, 235 insertions, 0 deletions
diff --git a/bcache-test.c b/bcache-test.c
new file mode 100644
index 0000000..33218e5
--- /dev/null
+++ b/bcache-test.c
@@ -0,0 +1,127 @@
+#define _XOPEN_SOURCE 500
+#define _GNU_SOURCE
+
+#include <assert.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <linux/fs.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+
+#define Pread(fd, buf, size, offset) do { \
+ int _read = 0, _r; \
+ while (_read < size) { \
+ _r = pread(fd, buf, (size) - _read, (offset) + _read); \
+ if (_r <= 0) \
+ goto err; \
+ _read += _r; \
+ } \
+} while (0)
+
+/* Marsaglia polar method
+ */
+double normal()
+{
+ double x, y, s;
+ static double n = 0 / (double) 0;
+
+ if (n == n) {
+ x = n;
+ n = 0 / (double) 0;
+ return x;
+ }
+
+ do {
+ x = random() / (double) (RAND_MAX / 2) - 1;
+ y = random() / (double) (RAND_MAX / 2) - 1;
+
+ s = x * x + y * y;
+ } while (s >= 1);
+
+ s = sqrt(-2 * log(s) / s);
+ n = y * s;
+ return x * s;
+}
+
+long getblocks(int fd)
+{
+ long ret;
+ struct stat statbuf;
+ if (fstat(fd, &statbuf)) {
+ perror("stat error\n");
+ exit(EXIT_FAILURE);
+ }
+ ret = statbuf.st_blocks;
+ if (S_ISBLK(statbuf.st_mode))
+ if (ioctl(fd, BLKGETSIZE, &ret)) {
+ perror("ioctl error");
+ exit(EXIT_FAILURE);
+ }
+ return ret;
+}
+
+int main(int argc, char **argv)
+{
+ bool walk = false, randsize = false, verbose = false;
+ int fd1, fd2, direct = 0;
+ long size, i;
+
+ if (argc < 3) {
+ printf("Please enter a cache device and raw device\n");
+ exit(EXIT_FAILURE);
+ }
+
+ for (i = 3; i < argc; i++) {
+ if (strcmp(argv[i], "direct") == 0)
+ direct = O_DIRECT;
+ if (strcmp(argv[i], "walk") == 0)
+ walk = true;
+ if (strcmp(argv[i], "verbose") == 0)
+ verbose = true;
+ if (strcmp(argv[i], "size") == 0)
+ randsize = true;
+ }
+
+ fd1 = open(argv[1], O_RDONLY|direct);
+ fd2 = open(argv[2], O_RDONLY|direct);
+ if (fd1 == -1 || fd2 == -1) {
+ perror("Error opening device");
+ exit(EXIT_FAILURE);
+ }
+
+ size = MIN(getblocks(fd1), getblocks(fd2)) / 8;
+ printf("size %li\n", size);
+
+ for (i = 0;; i++) {
+ char buf1[4096 * 16], buf2[4096 * 16];
+ long offset;
+ int pages = randsize ? MAX(MIN(abs(normal()) * 4, 16), 1) : 1;
+
+ offset = walk ? offset * normal() * 2 : random();
+ offset %= size;
+
+ if (verbose)
+ printf("Loop %li offset %li\n", i, offset);
+ else if (!(i % 100))
+ printf("Loop %li\n", i);
+
+ Pread(fd1, buf1, 4096 * pages, offset << 12);
+ Pread(fd2, buf2, 4096 * pages, offset << 12);
+
+ if (memcmp(buf1, buf2, 4096 * pages)) {
+ printf("Bad read! offset %li", offset << 12);
+ exit(EXIT_FAILURE);
+ }
+ }
+err:
+ perror("Read error");
+ exit(EXIT_FAILURE);
+}
diff --git a/make-bcache.c b/make-bcache.c
new file mode 100644
index 0000000..54828bb
--- /dev/null
+++ b/make-bcache.c
@@ -0,0 +1,108 @@
+#define _XOPEN_SOURCE 500
+
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+static const char bcache_magic[] = {
+ 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
+ 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81 };
+
+struct cache_sb {
+ uint8_t magic[16];
+ uint32_t version;
+ uint16_t block_size; /* sectors */
+ uint16_t bucket_size; /* sectors */
+ uint32_t journal_start; /* buckets */
+ uint32_t first_bucket; /* start of data */
+ uint64_t nbuckets; /* device size */
+ uint64_t btree_root;
+ uint16_t btree_level;
+};
+
+struct bucket_disk {
+ uint16_t priority;
+ uint8_t generation;
+} __attribute((packed));
+
+char zero[4096];
+
+int main(int argc, char **argv)
+{
+ long n;
+ int fd, i;
+ struct stat statbuf;
+ struct cache_sb sb;
+
+ if (argc < 2) {
+ printf("Please supply a device\n");
+ exit(EXIT_FAILURE);
+ }
+
+ fd = open(argv[1], O_RDWR);
+ if (!fd) {
+ perror("Can't open dev\n");
+ exit(EXIT_FAILURE);
+ }
+
+ if (fstat(fd, &statbuf)) {
+ perror("stat error\n");
+ exit(EXIT_FAILURE);
+ }
+ if (!S_ISBLK(statbuf.st_mode))
+ n = statbuf.st_blocks;
+ else
+ if (ioctl(fd, BLKGETSIZE, &n)) {
+ perror("ioctl error");
+ exit(EXIT_FAILURE);
+ }
+
+ memcpy(sb.magic, bcache_magic, 16);
+ sb.version = 0;
+ sb.block_size = 8;
+ sb.bucket_size = 32;
+ sb.nbuckets = n / sb.bucket_size;
+
+ do
+ sb.first_bucket = ((--sb.nbuckets * sizeof(struct bucket_disk))
+ + 4096 * 3) / (sb.bucket_size * 512) + 1;
+ while ((sb.nbuckets + sb.first_bucket) * sb.bucket_size * 512
+ > statbuf.st_size);
+
+ sb.journal_start = sb.first_bucket;
+
+ sb.btree_root = sb.first_bucket * sb.bucket_size;
+ sb.btree_level = 0;
+
+ printf("block_size: %u\n"
+ "bucket_size: %u\n"
+ "journal_start: %u\n"
+ "first_bucket: %u\n"
+ "nbuckets: %ju\n",
+ sb.block_size,
+ sb.bucket_size,
+ sb.journal_start,
+ sb.first_bucket,
+ sb.nbuckets);
+
+ /* Zero out priorities */
+ lseek(fd, 4096, SEEK_SET);
+ for (i = 8; i < sb.first_bucket * sb.bucket_size; i++)
+ if (write(fd, zero, 512) != 512)
+ goto err;
+
+ if (pwrite(fd, &sb, sizeof(sb), 4096) != sizeof(sb))
+ goto err;
+
+ exit(EXIT_SUCCESS);
+err:
+ perror("write error\n");
+ return 1;
+}