1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
|
/*
* 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.
*/
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <pthread.h>
#include <errno.h>
#include <err.h>
/*
* --------------------------------------------------------------------
* Bug Issue Id: #7512
* The bug time sequence:
* 1. context #1, zfs_write assign a txg "n".
* 2. In the same process, context #2, mmap page fault (which means the mm_sem
* is hold) occurred, zfs_dirty_inode open a txg failed, and wait previous
* txg "n" completed.
* 3. context #1 call uiomove to write, however page fault is occurred in
* uiomove, which means it need mm_sem, but mm_sem is hold by
* context #2, so it stuck and can't complete, then txg "n" will not
* complete.
*
* So context #1 and context #2 trap into the "dead lock".
* --------------------------------------------------------------------
*/
#define NORMAL_WRITE_TH_NUM 2
static void *
normal_writer(void *filename)
{
char *file_path = filename;
int fd = -1;
ssize_t write_num = 0;
int page_size = getpagesize();
fd = open(file_path, O_RDWR | O_CREAT, 0777);
if (fd == -1) {
err(1, "failed to open %s", file_path);
}
char *buf = malloc(1);
while (1) {
write_num = write(fd, buf, 1);
if (write_num == 0) {
err(1, "write failed!");
break;
}
lseek(fd, page_size, SEEK_CUR);
}
if (buf) {
free(buf);
}
}
static void *
map_writer(void *filename)
{
int fd = -1;
int ret = 0;
char *buf = NULL;
int page_size = getpagesize();
int op_errno = 0;
char *file_path = filename;
while (1) {
ret = access(file_path, F_OK);
if (ret) {
op_errno = errno;
if (op_errno == ENOENT) {
fd = open(file_path, O_RDWR | O_CREAT, 0777);
if (fd == -1) {
err(1, "open file failed");
}
ret = ftruncate(fd, page_size);
if (ret == -1) {
err(1, "truncate file failed");
}
} else {
err(1, "access file failed!");
}
} else {
fd = open(file_path, O_RDWR, 0777);
if (fd == -1) {
err(1, "open file failed");
}
}
if ((buf = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0)) == MAP_FAILED) {
err(1, "map file failed");
}
if (fd != -1)
close(fd);
char s[10] = {0, };
memcpy(buf, s, 10);
ret = munmap(buf, page_size);
if (ret != 0) {
err(1, "unmap file failed");
}
}
}
int
main(int argc, char **argv)
{
pthread_t map_write_tid;
pthread_t normal_write_tid[NORMAL_WRITE_TH_NUM];
int i = 0;
if (argc != 3) {
(void) printf("usage: %s <normal write file name>"
"<map write file name>\n", argv[0]);
exit(1);
}
for (i = 0; i < NORMAL_WRITE_TH_NUM; i++) {
if (pthread_create(&normal_write_tid[i], NULL, normal_writer,
argv[1])) {
err(1, "pthread_create normal_writer failed.");
}
}
if (pthread_create(&map_write_tid, NULL, map_writer, argv[2])) {
err(1, "pthread_create map_writer failed.");
}
/* NOTREACHED */
pthread_join(map_write_tid, NULL);
return (0);
}
|
