Date: Mon, 23 Jun 1997 20:14:52 +0900 From: pine@math.okayama-u.ac.jp To: FreeBSD-gnats-submit@FreeBSD.ORG Subject: kern/3938: Problem about mmap() over NFS Message-ID: <199706231114.UAA17960@decpc5.math.okayama-u.ac.jp> Resent-Message-ID: <199706231110.EAA28143@hub.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 3938
>Category: kern
>Synopsis: Problem about mmap() over NFS
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Mon Jun 23 04:10:00 PDT 1997
>Last-Modified:
>Originator: Hiroaki Komatsu
>Organization:
Okayama University
>Release: FreeBSD 2.1-STABLE i386
>Environment:
NFS server: SPARC station 20 running SunOS 4.1.3
NFS client: FreeBSD 2.2.2-RELEASE
FreeBSD 2.2.1-RELEASE
FreeBSD 2.1.0-RELEASE
>Description:
An ftp command `get foo' between different NFS clients for
a remote file `foo' of NFS causes ftpd to be frozen.
>How-To-Repeat:
I think that the following program causes the same trouble,
when an argument is a remote file of NFS, say `foo'. While
the program is sleeping 10 seconds, if another machine
executes `echo >foo' then write() call can not return.
------------------------------------------------------------
#include <stdio.h>
#include <sys/mman.h>
main(int argc, char *argv[])
{
FILE *fin;
char *buf;
if (argc != 2 || (fin = fopen(argv[1], "r")) == NULL) {
fprintf(stderr, "Usage: %s file\n", argv[0]);
exit(1);
}
fprintf(stderr, "sleep 10 seconds ...\n");
sleep(10);
buf = mmap(0, 1, PROT_READ, MAP_SHARED, fileno(fin), 0);
if ((int)buf == -1) {
fprintf(stderr, "? mmap\n");
exit(1);
}
write(1, buf, 1);
}
>Fix:
>Audit-Trail:
>Unformatted:
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199706231114.UAA17960>