1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or https://opensource.org/licenses/CDDL-1.0.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27/*
28 * Copyright (c) 2013 by Delphix. All rights reserved.
29 */
30
31#include <sys/types.h>
32#include <sys/stat.h>
33#include <fcntl.h>
34#include <pthread.h>
35#include <string.h>
36#include <stdio.h>
37#include <unistd.h>
38#include <stdlib.h>
39#include <errno.h>
40
41/*
42 * The size of the output file, "go.out", should be 80*8192*2 = 1310720
43 *
44 * $ cd /tmp; go; ls -l go.out
45 * done.
46 * -rwxr-xr-x	1 jdm	staff	1310720 Apr 13 19:45 go.out
47 * $ cd /zfs; go; ls -l go.out
48 * done.
49 * -rwxr-xr-x	1 jdm	staff	663552 Apr 13 19:45 go.out
50 *
51 * The file on zfs is short as it does not appear that zfs is making the
52 * implicit seek to EOF and the actual write atomic. From the SUSv3
53 * interface spec, behavior is undefined if concurrent writes are performed
54 * from multi-processes to a single file. So I don't know if this is a
55 * standards violation, but I cannot find any such disclaimers in our
56 * man pages. This issue came up at a customer site in another context, and
57 * the suggestion was to open the file with O_APPEND, but that wouldn't
58 * help with zfs(see 4977529). Also see bug# 5031301.
59 */
60
61static int outfd = 0;
62
63static void *
64go(void *data)
65{
66	int ret, i = 0, n = *(int *)data;
67	char buf[8192] = {0};
68	(void) memset(buf, n, sizeof (buf));
69
70	for (i = 0; i < 80; i++) {
71		ret = write(outfd, buf, sizeof (buf));
72		if (ret != sizeof (buf))
73			perror("write");
74	}
75	return (NULL);
76}
77
78static void
79usage(void)
80{
81	(void) fprintf(stderr,
82	    "usage: zfs_threadsappend <file name>\n");
83	exit(1);
84}
85
86int
87main(int argc, char **argv)
88{
89	pthread_t tid;
90	int	ret = 0;
91	long	ncpus = 0;
92	int	i;
93
94	if (argc != 2) {
95		usage();
96	}
97
98	ncpus = sysconf(_SC_NPROCESSORS_ONLN);
99	if (ncpus < 0) {
100		(void) fprintf(stderr,
101		    "Invalid return from sysconf(_SC_NPROCESSORS_ONLN)"
102		    " : errno (decimal)=%d\n", errno);
103		exit(1);
104	}
105	if (ncpus < 2) {
106		(void) fprintf(stderr,
107		    "Must execute this binary on a multi-processor system\n");
108		exit(1);
109	}
110
111	outfd = open(argv[optind++], O_RDWR|O_CREAT|O_APPEND|O_TRUNC, 0777);
112	if (outfd == -1) {
113		(void) fprintf(stderr,
114		    "zfs_threadsappend: "
115		    "open(%s, O_RDWR|O_CREAT|O_APPEND|O_TRUNC, 0777)"
116		    " failed\n", argv[optind]);
117		perror("open");
118		exit(1);
119	}
120
121	for (i = 0; i < 2; i++) {
122		ret = pthread_create(&tid, NULL, go, (void *)&i);
123		if (ret != 0) {
124			(void) fprintf(stderr,
125			    "zfs_threadsappend: thr_create(#%d) "
126			    "failed error=%d\n", i+1, ret);
127			exit(1);
128		}
129	}
130
131	while (pthread_join(tid, NULL) == 0)
132		continue;
133
134	return (0);
135}
136