zfs/tests/zfs-tests/cmd/clone_mmap_write.c

124 lines
2.8 KiB
C

/*
* 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 https://opensource.org/licenses/CDDL-1.0.
* 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
*/
/*
* This program clones the file, mmap it, and writes from the map into
* file. This scenario triggers a panic on Linux in dbuf_redirty(),
* which is fixed under PR#15656. On FreeBSD, the same test causes data
* corruption, which is fixed by PR#15665.
*
* It would be good to test for this scenario in ZTS. This program and
* issue was initially produced by @robn.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/mman.h>
#ifdef __FreeBSD__
#define loff_t off_t
#endif
ssize_t
copy_file_range(int, loff_t *, int, loff_t *, size_t, unsigned int)
__attribute__((weak));
static int
open_file(const char *source)
{
int fd;
if ((fd = open(source, O_RDWR | O_APPEND)) < 0) {
(void) fprintf(stderr, "Error opening %s\n", source);
exit(1);
}
sync();
return (fd);
}
static int
clone_file(int sfd, long long size, const char *dest)
{
int dfd;
if ((dfd = open(dest, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) < 0) {
(void) fprintf(stderr, "Error opening %s\n", dest);
exit(1);
}
if (copy_file_range(sfd, 0, dfd, 0, size, 0) < 0) {
(void) fprintf(stderr, "copy_file_range failed\n");
exit(1);
}
return (dfd);
}
static void *
map_file(int fd, long long size)
{
void *p = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
if (p == MAP_FAILED) {
(void) fprintf(stderr, "mmap failed\n");
exit(1);
}
return (p);
}
static void
map_write(void *p, int fd)
{
if (pwrite(fd, p, 1024*128, 0) < 0) {
(void) fprintf(stderr, "write failed\n");
exit(1);
}
}
int
main(int argc, char **argv)
{
int sfd, dfd;
void *p;
struct stat sb;
if (argc != 3) {
(void) printf("usage: %s <input source file> "
"<clone destination file>\n", argv[0]);
exit(1);
}
sfd = open_file(argv[1]);
if (fstat(sfd, &sb) == -1) {
(void) fprintf(stderr, "fstat failed\n");
exit(1);
}
dfd = clone_file(sfd, sb.st_size, argv[2]);
p = map_file(dfd, sb.st_size);
map_write(p, dfd);
return (0);
}