/*
 * nfsbug.c
 * exercises a bug in Linux 2.4/2.5 client NFS
 * If the parent directory of an unlinked-but-open file goes away,
 * kernel reports "inode mismatch".
 *
 * nfsbug <nfsdir>
 */

#include <stdio.h>
#include <string.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <unistd.h>

int
main(int argc, char *argv[])
{
    char path[2048];
    char file[2048];
    int fd;
    int v = 1, r;
    struct dirent *d;
    DIR *dir;

    if (argc != 2)
	exit(1);

    /* create a dir "t" under <nfsdir> */
    sprintf(path, "%s/%s", argv[1], "t");
    if (mkdir(path, 0777) < 0)
	exit(1);

    /* create a file "foo" under <nfsdir>/t */
    sprintf(file, "%s/%s", path, "foo");
    if ((fd = open(file, O_CREAT, 0666)) < 0)
	exit(1);

    /*
     * ok, we're now holding the file open, do an rm -rf.
     * We have to readdir() because unlinking <file> over NFS does a rename
     * (otherwise we could just unlink it and then do rmdir).
     * The readdir() returns foo, then the renamed file (which, when unlinked,
     * really gets unlinked, not renamed).
     */
    if ((dir = opendir(path)) == NULL)
	exit(1);
    while (d = readdir(dir)) {
	if (!strcmp(".", d->d_name) || !strcmp("..", d->d_name))
	    continue;
	sprintf(file, "%s/%s", path, d->d_name);
	r = unlink(file);
	if (v && r == 0)
	    printf("unlinked %s\n", file);
	else if (v && r < 0)
	    printf("failed to unlink %s\n", file);
    }
    if (rmdir(path) < 0)
	printf("failed to rmdir %s\n", path);
    else
	printf("rmdir-ed %s\n", path);

    /* exit, which tries to unlink the .nfs file again */
    printf("exit: ");
    fgets((char *)&r, 2, stdin);

    exit(0);
}