tests/zfs-tests/cmd/clone_mmap_write.c

   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 https://opensource.org/licenses/CDDL-1.0.
  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  * This program clones the file, mmap it, and writes from the map into
  24  * file. This scenario triggers a panic on Linux in dbuf_redirty(),
  25  * which is fixed under PR#15656. On FreeBSD, the same test causes data
  26  * corruption, which is fixed by PR#15665.
  27  *
  28  * It would be good to test for this scenario in ZTS. This program and
  29  * issue was initially produced by @robn.
  30  */
  31 #ifndef _GNU_SOURCE
  32 #define _GNU_SOURCE
  33 #endif
  34
  35 #include <fcntl.h>
  36 #include <string.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <unistd.h>
  40 #include <errno.h>
  41 #include <sys/stat.h>
  42 #include <sys/mman.h>
  43
  44 #ifdef __FreeBSD__
  45 #define loff_t  off_t
  46 #endif
  47
  48 ssize_t
  49 copy_file_range(int, loff_t *, int, loff_t *, size_t, unsigned int)
  50     __attribute__((weak));
  51
  52 static int
  53 open_file(const char *source)
  54 {
  55         int fd;
  56         if ((fd = open(source, O_RDWR | O_APPEND)) < 0) {
  57                 (void) fprintf(stderr, "Error opening %s\n", source);
  58                 exit(1);
  59         }
  60         sync();
  61         return (fd);
  62 }
  63
  64 static int
  65 clone_file(int sfd, long long size, const char *dest)
  66 {
  67         int dfd;
  68
  69         if ((dfd = open(dest, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) < 0) {
  70                 (void) fprintf(stderr, "Error opening %s\n", dest);
  71                 exit(1);
  72         }
  73
  74         if (copy_file_range(sfd, 0, dfd, 0, size, 0) < 0) {
  75                 (void) fprintf(stderr, "copy_file_range failed\n");
  76                 exit(1);
  77         }
  78
  79         return (dfd);
  80 }
  81
  82 static void *
  83 map_file(int fd, long long size)
  84 {
  85         void *p = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
  86         if (p == MAP_FAILED) {
  87                 (void) fprintf(stderr, "mmap failed\n");
  88                 exit(1);
  89         }
  90
  91         return (p);
  92 }
  93
  94 static void
  95 map_write(void *p, int fd)
  96 {
  97         if (pwrite(fd, p, 1024*128, 0) < 0) {
  98                 (void) fprintf(stderr, "write failed\n");
  99                 exit(1);
 100         }
 101 }
 102
 103 int
 104 main(int argc, char **argv)
 105 {
 106         int sfd, dfd;
 107         void *p;
 108         struct stat sb;
 109         if (argc != 3) {
 110                 (void) printf("usage: %s <input source file> "
 111                     "<clone destination file>\n", argv[0]);
 112                 exit(1);
 113         }
 114         sfd = open_file(argv[1]);
 115         if (fstat(sfd, &sb) == -1) {
 116                 (void) fprintf(stderr, "fstat failed\n");
 117                 exit(1);
 118         }
 119         dfd = clone_file(sfd, sb.st_size, argv[2]);
 120         p = map_file(dfd, sb.st_size);
 121         map_write(p, dfd);
 122         return (0);
 123 }