Initial commit

1 files changed, 127 insertions, 0 deletions

diff --git a/bcache-test.c b/bcache-test.c
new file mode 100644
index 00000000..33218e53
--- /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);
+}