Created
July 23, 2017 09:43
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nfs_halfpage
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/* $Id: nfs_halfpage.c,v 1.2 2017/07/23 09:36:23 kostik Exp kostik $ */ | |
#include <sys/fcntl.h> | |
#include <sys/mman.h> | |
#include <err.h> | |
#include <unistd.h> | |
int | |
main(int argc __unused, char *argv[]) | |
{ | |
char *m; | |
int error, fd, pgsz, sz; | |
pgsz = getpagesize(); | |
fd = open(argv[1], O_RDWR | O_CREAT | O_TRUNC, 0666); | |
if (fd == -1) | |
err(1, "open %s", argv[1]); | |
sz = pgsz / 4; | |
error = lseek(fd, sz, SEEK_SET); | |
if (error == -1) | |
err(1, "lseek"); | |
error = write(fd, "a", 1); | |
if (error == -1) | |
err(1, "write"); | |
else if (error != 1) | |
errx(1, "short write"); | |
m = mmap(NULL, sz + 1, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); | |
if (m == MAP_FAILED) | |
err(1, "mmap"); | |
m[0] = 'x'; | |
} |
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Run this program with the argument a filename to be created on an nfs mount, then reboot the machine. It should loop syncing vnodes and buffers.