On Sat, Nov 15, 2008 at 02:28:31PM +0100, Frank van Maarseveen wrote:
> Try running multiple instances of attached program on 1 NFS client
> against a 2.6.27(.5) NFSv3 server:
>
> gcc -Wall -Wstrict-prototypes -o lck lck.c
> for i in `seq 30`
> do
> lck &
> done
Or reproduceable using the "flock" utility with:
for i in `seq 30`
do
flock /mnt/foo sleep 10
done
Hm. What's the last known good server version?
--b.
>
> Depending on the client linux version one or more processes hang
> indefinately (on 2.6.22) or receive a ENOLCK (on 2.6.27), printing:
>
> lck: fcntl: No locks available
>
> Either way, /proc/locks on the server grows indefinately.
>
> --
> Frank
> #include <stdio.h>
> #include <ctype.h>
> #include <unistd.h>
> #include <fcntl.h>
> #include <errno.h>
> #include <string.h>
> #include <stdarg.h>
> #include <stdlib.h>
>
> void die(const char *fmt, ...) __attribute__((format(printf, 1, 2), noreturn));
> void die(const char *fmt, ...)
> {
> va_list ap;
>
> va_start(ap, fmt);
> fprintf(stderr, "lck: ");
> vfprintf(stderr, fmt, ap);
> va_end(ap);
> exit(1);
> }
>
> int main(int argc, char **argv)
> {
> struct flock flock = {0};
> int i, d, locktime, cmd;
> const char *name;
>
> flock.l_type = F_WRLCK; /* -w */
> flock.l_whence = SEEK_SET;
> cmd = F_SETLKW; /* no -t */
> name = NULL;
> locktime = 10;
> for (i = 1; i < argc; ++i) {
> if (strcmp(argv[i], "-r") == 0)
> flock.l_type = F_RDLCK; /* lock for N readers */
> else if (strcmp(argv[i], "-w") == 0)
> flock.l_type = F_WRLCK; /* lock for 1 writer */
> else if (strcmp(argv[i], "-t") == 0)
> cmd = F_SETLK; /* test for a lock, don't wait */
> else if (argv[i][0] == '-')
> die("Usage: lck [-r|-w] [-t] [<filename> [<locktime>]]\n");
> else if (name && isdigit(argv[i][0]))
> locktime = atoi(argv[i]); /* after acquiring lock, wait locktime seconds */
> else
> name = argv[i];
> }
> if (!name)
> name = "lck-filename";
> d = open(name, O_RDWR|O_CREAT, 0666);
> if (d == -1)
> die("open %s: %s\n", name, strerror(errno));
> if (fcntl(d, cmd, &flock) == -1)
> die("fcntl: %s\n", strerror(errno));
> printf("locked...");
> fflush(NULL);
> sleep(locktime);
> if (close(d))
> die("close: %s\n", strerror(errno));
> printf("unlocked.\n");
> return 0;
> }
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
