/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2014, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 */

/* for O_DIRECT */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <linux/types.h>

#define READ  1
#define WRITE 2

#define LPDS sizeof(uint64_t)
static int block_debug_setup(void *addr, int len, uint64_t off, uint64_t id)
{
	off = htole64(off);
	id = htole64(id);
	memcpy(addr, (char *)&off, LPDS);
	memcpy(addr + LPDS, (char *)&id, LPDS);

	addr += len - LPDS - LPDS;
	memcpy(addr, (char *)&off, LPDS);
	memcpy(addr + LPDS, (char *)&id, LPDS);

	return 0;
}

static int block_debug_check(char *who, void *addr, int size, uint64_t off,
		      uint64_t id)
{
	uint64_t ne_off;
	int err = 0;

	ne_off = le64toh(off);
	id = le64toh(id);
	if (memcmp(addr, (char *)&ne_off, LPDS)) {
		fprintf(stderr, "%s: for offset %"PRIu64" off: %"PRIx64" != %"PRIx64"\n",
			who, off, *(uint64_t *)addr, ne_off);
		err = -EINVAL;
	}
	if (memcmp(addr + LPDS, (char *)&id, LPDS)) {
		fprintf(stderr, "%s: for offset %"PRIu64" id: %"PRIx64" != %"PRIx64"\n",
			who, off, *(uint64_t *)(addr + LPDS), id);
		err = -EINVAL;
	}

	addr += size - LPDS - LPDS;
	if (memcmp(addr, (char *)&ne_off, LPDS)) {
		fprintf(stderr, "%s: for offset %"PRIu64" end off: %"PRIx64" != %"PRIx64"\n",
			who, off, *(uint64_t *)addr, ne_off);
		err = -EINVAL;
	}
	if (memcmp(addr + LPDS, (char *)&id, LPDS)) {
		fprintf(stderr, "%s: for offset %"PRIu64" end id: %"PRIx64" != %"PRIx64"\n",
			who, off, *(uint64_t *)(addr + LPDS), id);
		err = -EINVAL;
	}

	return err;
}

#undef LPDS

static void usage(char *prog)
{
	fprintf(stderr,
		"usage: %s file count [[d]{r|w|rw} [pages_per_vec [objid]]]\n",
		prog);
	exit(1);
}

int main(int argc, char **argv)
{
	int fd;
	char *buf;
	long long count, last;
	size_t pg_vec, len;
	uint64_t objid, offset;
	struct stat st;
	int flags = 0;
	int cmd = 0;
	char *end;
	int rc;

	if (argc < 3 || argc > 6)
		usage(argv[0]);

	count = strtoull(argv[2], &end, 0);
	if (*end) {
		fprintf(stderr, "%s: invalid count '%s'\n", argv[0], argv[2]);
		usage(argv[0]);
	}
	if (argc >= 4) {
		if (strchr(argv[3], 'r')) {
			cmd = READ;
			flags = O_RDONLY;
		}
		if (strchr(argv[3], 'w')) {
			cmd |= WRITE;
			flags = O_RDWR | O_CREAT;
		}
		if (strchr(argv[3], 'd')) {
#ifdef O_DIRECT
			flags |= O_DIRECT;
#else
			fprintf(stderr,
				"%s: O_DIRECT not supported in this build\n",
				argv[0]);
			exit(1);
#endif
		}
		if (!cmd)
			usage(argv[0]);
	} else {
		cmd = READ | WRITE;
		flags = O_RDWR | O_CREAT;
#ifdef O_DIRECT
		flags |= O_DIRECT;
#else
		fprintf(stderr, "%s: warning: not setting O_DIRECT\n",
			argv[0]);
#endif
	}

	if (argc >= 5) {
		pg_vec = strtoul(argv[4], &end, 0);
		if (*end) {
			fprintf(stderr, "%s: invalid pages_per_vec '%s'\n",
				argv[0], argv[4]);
			usage(argv[0]);
		}
	} else {
		pg_vec = 16;
	}

	if (argc >= 6) {
		objid = strtoull(argv[5], &end, 0);
		if (*end) {
			fprintf(stderr, "%s: invalid objid '%s'\n",
				argv[0], argv[5]);
			usage(argv[0]);
		}
	} else {
		objid = 3;
	}

	printf("%s: %s on %s(objid %"PRIx64") for %llux%ld pages\n",
	       argv[0],
#ifdef O_DIRECT
	       flags & O_DIRECT ? "directio" : "i/o",
#else
	       "i/o",
#endif
	       argv[1], objid, count, pg_vec);

	fd = open(argv[1], flags | O_LARGEFILE);
	if (fd == -1) {
		fprintf(stderr, "%s: cannot open %s:  %s\n", argv[0],
			argv[1], strerror(errno));
		return 3;
	}

	rc = fstat(fd, &st);
	if (rc < 0) {
		fprintf(stderr, "%s: cannot stat %s: %s\n", argv[0],
			argv[1], strerror(errno));
		return 4;
	}

	len = pg_vec * st.st_blksize;
	last = (long long)count * len;

	buf = mmap(0, len, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON,
		   0, 0);
	if (buf == MAP_FAILED) {
		fprintf(stderr, "%s: no buffer memory %s\n",
			argv[0], strerror(errno));
		return 2;
	}

	for (offset = 0; offset < last && cmd & WRITE; offset += len) {
		unsigned int i;

		for (i = 0; i < len; i += st.st_blksize)
			block_debug_setup(buf + i, st.st_blksize,
					  offset + i, objid);

		rc = write(fd, buf, len);

		for (i = 0; i < len; i += st.st_blksize) {
			if (block_debug_check("write", buf + i, st.st_blksize,
					      offset + i, objid))
				return 10;
		}

		if (rc != len) {
			fprintf(stderr, "%s: write error: %s, rc %d != %ld\n",
				argv[0], strerror(errno), rc, len);
			return 4;
		}
	}

	if (lseek(fd, 0, SEEK_SET) != 0) {
		fprintf(stderr, "%s: cannot seek %s\n",
			argv[0], strerror(errno));
		return 5;
	}

	for (offset = 0; offset < last && cmd & READ; offset += len) {
		int i;

		rc = read(fd, buf, len);
		if (rc != len) {
			fprintf(stderr, "%s: read error: %s, rc %d != %ld\n",
				argv[0], strerror(errno), rc, len);
			return 6;
		}

		for (i = 0; i < len; i += st.st_blksize) {
			if (block_debug_check("read", buf + i, st.st_blksize,
					      offset + i, objid))
				return 11;
		}
	}

	return 0;
}