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/*
* 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 zfs_uiomove to write, however page fault is occurred in
* zfs_uiomove, which means it needs 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;
while (1) {
write_num = write(fd, &buf, 1);
if (write_num == 0) {
err(1, "write failed!");
break;
}
lseek(fd, page_size, SEEK_CUR);
}
}
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.");
}
pthread_join(map_write_tid, NULL);
return (0);
}
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