12 #define PAGE(a) ((a)*0x1000)
15 void err_exit(char *op)
17 fprintf(stderr, "%s: %s\n", op, strerror(errno));
21 int main(int argc, char *argv[])
23 int fd, err, len = PAGE(1);
24 char *dax_data, *data;
28 printf("Usage: %s <file>\n", basename(argv[0]));
33 snprintf(string, STRLEN, "random number %d\n", rand());
35 fd = open(argv[1], O_RDWR);
39 data = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
41 err_exit("mmap data");
43 /* this fallocate turns off inline data and turns on DAX */
44 fallocate(fd, 0, 0, PAGE(2));
46 dax_data = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, 0);
48 err_exit("mmap dax_data");
51 * Write the data using the non-DAX mapping, and try and read it back
52 * using the DAX mapping.
55 if (strcmp(dax_data, string) != 0)
56 printf("Data miscompare\n");
58 err = munmap(dax_data, len);
60 err_exit("munmap dax_data");
62 err = munmap(data, len);
64 err_exit("munmap data");