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/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2011 New Dream Network
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#include <errno.h>
#include <inttypes.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
/*
* direct_io_test
*
* This test does some I/O using O_DIRECT.
*
* Semantics of O_DIRECT can be found at http://lwn.net/Articles/348739/
*
*/
static int g_num_pages = 100;
static int g_duration = 10;
struct chunk {
uint64_t offset;
uint64_t pad0;
uint64_t pad1;
uint64_t pad2;
uint64_t pad3;
uint64_t pad4;
uint64_t pad5;
uint64_t not_offset;
} __attribute__((packed));
static int page_size;
static char temp_file[] = "direct_io_temp_file_XXXXXX";
static int safe_write(int fd, const void *buf, signed int len)
{
const char *b = (const char*)buf;
/* Handle EINTR and short writes */
while (1) {
int res = write(fd, b, len);
if (res < 0) {
int err = errno;
if (err != EINTR) {
return err;
}
}
len -= res;
b += res;
if (len <= 0)
return 0;
}
}
static int do_read(int fd, char *buf, int buf_sz)
{
/* We assume no short reads or EINTR. It's not really clear how
* those things interact with O_DIRECT. */
int ret = read(fd, buf, buf_sz);
if (ret < 0) {
int err = errno;
printf("do_read: error: %d (%s)\n", err, strerror(err));
return err;
}
if (ret != buf_sz) {
printf("do_read: short read\n");
return -EIO;
}
return 0;
}
static int setup_temp_file(void)
{
int fd;
int64_t num_chunks, i;
if (page_size % sizeof(struct chunk)) {
printf("setup_big_file: page_size doesn't divide evenly "
"into data blocks.\n");
return -EINVAL;
}
fd = mkstemp(temp_file);
if (fd < 0) {
int err = errno;
printf("setup_big_file: mkostemps failed with error %d\n", err);
return err;
}
num_chunks = g_num_pages * (page_size / sizeof(struct chunk));
for (i = 0; i < num_chunks; ++i) {
int ret;
struct chunk c;
memset(&c, 0, sizeof(c));
c.offset = i * sizeof(struct chunk);
c.pad0 = 0;
c.pad1 = 1;
c.pad2 = 2;
c.pad3 = 3;
c.pad4 = 4;
c.pad5 = 5;
c.not_offset = ~c.offset;
ret = safe_write(fd, &c, sizeof(struct chunk));
if (ret) {
printf("setup_big_file: safe_write failed with "
"error: %d\n", ret);
TEMP_FAILURE_RETRY(close(fd));
unlink(temp_file);
return ret;
}
}
TEMP_FAILURE_RETRY(close(fd));
return 0;
}
static int verify_chunk(const struct chunk *c, uint64_t offset)
{
if (c->offset != offset) {
printf("verify_chunk(%" PRId64 "): bad offset value (got: %"
PRId64 ", expected: %" PRId64 "\n", offset, c->offset, offset);
return EIO;
}
if (c->pad0 != 0) {
printf("verify_chunk(%" PRId64 "): bad pad0 value\n", offset);
return EIO;
}
if (c->pad1 != 1) {
printf("verify_chunk(%" PRId64 "): bad pad1 value\n", offset);
return EIO;
}
if (c->pad2 != 2) {
printf("verify_chunk(%" PRId64 "): bad pad2 value\n", offset);
return EIO;
}
if (c->pad3 != 3) {
printf("verify_chunk(%" PRId64 "): bad pad3 value\n", offset);
return EIO;
}
if (c->pad4 != 4) {
printf("verify_chunk(%" PRId64 "): bad pad4 value\n", offset);
return EIO;
}
if (c->pad5 != 5) {
printf("verify_chunk(%" PRId64 "): bad pad5 value\n", offset);
return EIO;
}
if (c->not_offset != ~offset) {
printf("verify_chunk(%" PRId64 "): bad not_offset value\n",
offset);
return EIO;
}
return 0;
}
static int do_o_direct_reads(void)
{
int fd, ret;
unsigned int i;
void *buf = 0;
time_t cur_time, end_time;
ret = posix_memalign(&buf, page_size, page_size);
if (ret) {
printf("do_o_direct_reads: posix_memalign returned %d\n", ret);
goto done;
}
fd = open(temp_file, O_RDONLY | O_DIRECT);
if (fd < 0) {
ret = errno;
printf("do_o_direct_reads: error opening fd: %d\n", ret);
goto free_buf;
}
// read the first chunk and see if it looks OK
ret = do_read(fd, buf, page_size);
if (ret)
goto close_fd;
ret = verify_chunk((struct chunk*)buf, 0);
if (ret)
goto close_fd;
// read some random chunks and see how they look
cur_time = time(NULL);
end_time = cur_time + g_duration;
i = 0;
do {
time_t next_time;
uint64_t offset;
int page;
unsigned int seed;
seed = i++;
page = rand_r(&seed) % g_num_pages;
offset = page;
offset *= page_size;
if (lseek64(fd, offset, SEEK_SET) == -1) {
int err = errno;
printf("lseek64(%" PRId64 ") failed: error %d (%s)\n",
offset, err, strerror(err));
goto close_fd;
}
ret = do_read(fd, buf, page_size);
if (ret)
goto close_fd;
ret = verify_chunk((struct chunk*)buf, offset);
if (ret)
goto close_fd;
next_time = time(NULL);
if (next_time > cur_time) {
printf(".");
}
cur_time = next_time;
} while (time(NULL) < end_time);
printf("\ndo_o_direct_reads: SUCCESS\n");
close_fd:
TEMP_FAILURE_RETRY(close(fd));
free_buf:
free(buf);
done:
return ret;
}
static void usage(char *argv0)
{
printf("%s: tests direct I/O\n", argv0);
printf("-d <seconds>: sets duration to <seconds>\n");
printf("-h: this help\n");
printf("-p <pages>: sets number of pages to allocate\n");
}
static void parse_args(int argc, char *argv[])
{
int c;
while ((c = getopt (argc, argv, "d:hp:")) != -1) {
switch (c) {
case 'd':
g_duration = atoi(optarg);
if (g_duration <= 0) {
printf("tried to set invalid value of "
"g_duration: %d\n", g_num_pages);
exit(1);
}
break;
case 'h':
usage(argv[0]);
exit(0);
break;
case 'p':
g_num_pages = atoi(optarg);
if (g_num_pages <= 0) {
printf("tried to set invalid value of "
"g_num_pages: %d\n", g_num_pages);
exit(1);
}
break;
case '?':
usage(argv[0]);
exit(1);
break;
default:
usage(argv[0]);
exit(1);
break;
}
}
}
int main(int argc, char *argv[])
{
int ret;
parse_args(argc, argv);
setvbuf(stdout, NULL, _IONBF, 0);
page_size = getpagesize();
ret = setup_temp_file();
if (ret) {
printf("setup_temp_file failed with error %d\n", ret);
goto done;
}
ret = do_o_direct_reads();
if (ret) {
printf("do_o_direct_reads failed with error %d\n", ret);
goto unlink_temp_file;
}
unlink_temp_file:
unlink(temp_file);
done:
return ret;
}
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