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 http://www.opensolaris.org/os/licensing.
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 <thread.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
61 static int outfd = 0;
62
63 static void *
go(void * data)64 go(void *data)
65 {
66 int 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 (void) write(outfd, buf, sizeof (buf));
72 }
73 return (NULL);
74 }
75
76 static void
usage()77 usage()
78 {
79 (void) fprintf(stderr,
80 "usage: zfs_threadsappend <file name>\n");
81 exit(1);
82 }
83
84 int
main(int argc,char ** argv)85 main(int argc, char **argv)
86 {
87 int ret = 0;
88 long ncpus = 0;
89 int i;
90
91 if (argc != 2) {
92 usage();
93 }
94
95 ncpus = sysconf(_SC_NPROCESSORS_ONLN);
96 if (ncpus < 0) {
97 (void) fprintf(stderr,
98 "Invalid return from sysconf(_SC_NPROCESSORS_ONLN)"
99 " : errno (decimal)=%d\n", errno);
100 exit(1);
101 }
102 if (ncpus < 2) {
103 (void) fprintf(stderr,
104 "Must execute this binary on a multi-processor system\n");
105 exit(1);
106 }
107
108 outfd = open(argv[optind++], O_RDWR|O_CREAT|O_APPEND|O_TRUNC, 0777);
109 if (outfd == -1) {
110 (void) fprintf(stderr,
111 "zfs_threadsappend: "
112 "open(%s, O_RDWR|O_CREAT|O_APPEND|O_TRUNC, 0777)"
113 " failed\n", argv[optind]);
114 perror("open");
115 exit(1);
116 }
117
118 for (i = 0; i < 2; i++) {
119 ret = thr_create(NULL, 0, go, (void *)&i, 0, NULL);
120 if (ret != 0) {
121 (void) fprintf(stderr,
122 "zfs_threadsappend: thr_create(#%d) "
123 "failed error=%d\n", i+1, ret);
124 exit(1);
125 }
126 }
127
128 while (thr_join(0, NULL, NULL) == 0)
129 continue;
130
131 return (0);
132 }
133