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 * 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 77 usage() 78 { 79 (void) fprintf(stderr, 80 "usage: zfs_threadsappend <file name>\n"); 81 exit(1); 82 } 83 84 int 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