1 files changed, 135 insertions, 0 deletions
diff --git a/sys/contrib/openzfs/tests/zfs-tests/cmd/threadsappend/threadsappend.c b/sys/contrib/openzfs/tests/zfs-tests/cmd/threadsappend/threadsappend.c
new file mode 100644
index 000000000000..25710a3c12ef
--- /dev/null
+++ b/sys/contrib/openzfs/tests/zfs-tests/cmd/threadsappend/threadsappend.c
@@ -0,0 +1,135 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*
+ * Copyright (c) 2013 by Delphix. All rights reserved.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+
+/*
+ * The size of the output file, "go.out", should be 80*8192*2 = 1310720
+ *
+ * $ cd /tmp; go; ls -l go.out
+ * done.
+ * -rwxr-xr-x	1 jdm	staff	1310720 Apr 13 19:45 go.out
+ * $ cd /zfs; go; ls -l go.out
+ * done.
+ * -rwxr-xr-x	1 jdm	staff	663552 Apr 13 19:45 go.out
+ *
+ * The file on zfs is short as it does not appear that zfs is making the
+ * implicit seek to EOF and the actual write atomic. From the SUSv3
+ * interface spec, behavior is undefined if concurrent writes are performed
+ * from multi-processes to a single file. So I don't know if this is a
+ * standards violation, but I cannot find any such disclaimers in our
+ * man pages. This issue came up at a customer site in another context, and
+ * the suggestion was to open the file with O_APPEND, but that wouldn't
+ * help with zfs(see 4977529). Also see bug# 5031301.
+ */
+
+static int outfd = 0;
+
+static void *
+go(void *data)
+{
+	int ret, i = 0, n = *(int *)data;
+	char buf[8192] = {0};
+	(void) memset(buf, n, sizeof (buf));
+
+	for (i = 0; i < 80; i++) {
+		ret = write(outfd, buf, sizeof (buf));
+		if (ret != sizeof (buf))
+			perror("write");
+	}
+	return (NULL);
+}
+
+static void
+usage(void)
+{
+	(void) fprintf(stderr,
+	    "usage: zfs_threadsappend <file name>\n");
+	exit(1);
+}
+
+int
+main(int argc, char **argv)
+{
+	pthread_t tid;
+	int	ret = 0;
+	long	ncpus = 0;
+	int	i;
+
+	if (argc != 2) {
+		usage();
+	}
+
+	ncpus = sysconf(_SC_NPROCESSORS_ONLN);
+	if (ncpus < 0) {
+		(void) fprintf(stderr,
+		    "Invalid return from sysconf(_SC_NPROCESSORS_ONLN)"
+		    " : errno (decimal)=%d\n", errno);
+		exit(1);
+	}
+	if (ncpus < 2) {
+		(void) fprintf(stderr,
+		    "Must execute this binary on a multi-processor system\n");
+		exit(1);
+	}
+
+	outfd = open(argv[optind++], O_RDWR|O_CREAT|O_APPEND|O_TRUNC, 0777);
+	if (outfd == -1) {
+		(void) fprintf(stderr,
+		    "zfs_threadsappend: "
+		    "open(%s, O_RDWR|O_CREAT|O_APPEND|O_TRUNC, 0777)"
+		    " failed\n", argv[optind]);
+		perror("open");
+		exit(1);
+	}
+
+	for (i = 0; i < 2; i++) {
+		ret = pthread_create(&tid, NULL, go, (void *)&i);
+		if (ret != 0) {
+			(void) fprintf(stderr,
+			    "zfs_threadsappend: thr_create(#%d) "
+			    "failed error=%d\n", i+1, ret);
+			exit(1);
+		}
+	}
+
+	while (pthread_join(tid, NULL) == 0)
+		continue;
+
+	return (0);
+}