1#!/bin/sh
2
3#
4# Copyright (c) 2008 Peter Holm <pho@FreeBSD.org>
5# All rights reserved.
6#
7# Redistribution and use in source and binary forms, with or without
8# modification, are permitted provided that the following conditions
9# are met:
10# 1. Redistributions of source code must retain the above copyright
11#    notice, this list of conditions and the following disclaimer.
12# 2. Redistributions in binary form must reproduce the above copyright
13#    notice, this list of conditions and the following disclaimer in the
14#    documentation and/or other materials provided with the distribution.
15#
16# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26# SUCH DAMAGE.
27#
28# $FreeBSD$
29#
30
31# Alternate buffer flush path test (Not verified)
32# Apply this patch to amplyfy the problem:
33#
34# diff -r1.520 vfs_bio.c
35# 894c894
36# <       if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10) {
37# ---
38# >       if (bo->bo_dirty.bv_cnt > dirtybufthresh /*+ 10*/) {
39
40odir=`pwd`
41dir=/var/tmp/alternativeFlushPath
42
43find $dir -type f | xargs rm
44[ ! -d $dir ] && mkdir -p $dir
45cd $dir
46sed '1,/^EOF/d' < $odir/$0 > $dir/alternativeFlushPath.c
47cc -o alternativeFlushPath -Wall alternativeFlushPath.c -lthr
48rm -f alternativeFlushPath.c
49
50for j in `jot 10`; do
51   ./alternativeFlushPath&
52done
53for j in `jot 20`; do
54   wait
55done
56sysctl -a | grep dirtybuf
57
58rm alternativeFlushPath
59
60exit
61
62EOF
63#include <stdio.h>
64#include <unistd.h>
65#include <stdlib.h>
66#include <fcntl.h>
67#include <sys/types.h>
68#include <sys/time.h>
69#include <sys/resource.h>
70#include <err.h>
71
72int
73main()
74{
75        char name[80];
76        int i, j, k;
77        pid_t mypid;
78        int *fd;
79        struct rlimit rlp;
80
81
82        if (getrlimit(RLIMIT_NOFILE, &rlp) == -1)
83                err(1, "getrlimit(RLIMIT_NOFILE)");
84	rlp.rlim_cur /= 10;
85        mypid = getpid();
86        fd = malloc(rlp.rlim_cur * sizeof(int));
87
88	for (k = 0; k < 100; k++) {
89        for (i = 0, j = 0; i < (rlp.rlim_cur - 10); i++, j++) {
90                sprintf(name, "f%05d.%05d", mypid, i);
91                if ((fd[i] = open(name, O_CREAT|O_WRONLY, 0666)) == -1) {
92                        warn("open(%s)", name);
93                        break;
94                }
95        }
96        for (i = 0; i < j; i++) {
97                sprintf(name, "f%05d.%05d", mypid, i);
98                if (unlink(name) == -1)
99                        warn("unlink(%s)", name);
100        }
101        for (i = 0; i < j; i++) {
102                if (close(fd[i]) == -1)
103                        warn("close(%d)", i);
104        }
105	}
106
107        exit(0);
108}
109