#!/bin/sh

#
# Copyright (c) 2008 Peter Holm <pho@FreeBSD.org>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#

# Alternate buffer flush path test (Not verified)
# Apply this patch to amplyfy the problem:
#
# diff -r1.520 vfs_bio.c
# 894c894
# <       if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10) {
# ---
# >       if (bo->bo_dirty.bv_cnt > dirtybufthresh /*+ 10*/) {

odir=`pwd`
dir=/var/tmp/alternativeFlushPath

find $dir -type f | xargs rm
[ ! -d $dir ] && mkdir -p $dir
cd $dir
sed '1,/^EOF/d' < $odir/$0 > $dir/alternativeFlushPath.c
cc -o alternativeFlushPath -Wall alternativeFlushPath.c -lthr
rm -f alternativeFlushPath.c

for j in `jot 10`; do
   ./alternativeFlushPath&
done
for j in `jot 20`; do
   wait
done
sysctl -a | grep dirtybuf

rm alternativeFlushPath

exit

EOF
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <err.h>

int
main()
{
        char name[80];
        int i, j, k;
        pid_t mypid;
        int *fd;
        struct rlimit rlp;


        if (getrlimit(RLIMIT_NOFILE, &rlp) == -1)
                err(1, "getrlimit(RLIMIT_NOFILE)");
	rlp.rlim_cur /= 10;
        mypid = getpid();
        fd = malloc(rlp.rlim_cur * sizeof(int));

	for (k = 0; k < 100; k++) {
        for (i = 0, j = 0; i < (rlp.rlim_cur - 10); i++, j++) {
                sprintf(name, "f%05d.%05d", mypid, i);
                if ((fd[i] = open(name, O_CREAT|O_WRONLY, 0666)) == -1) {
                        warn("open(%s)", name);
                        break;
                }
        }
        for (i = 0; i < j; i++) {
                sprintf(name, "f%05d.%05d", mypid, i);
                if (unlink(name) == -1)
                        warn("unlink(%s)", name);
        }
        for (i = 0; i < j; i++) {
                if (close(fd[i]) == -1)
                        warn("close(%d)", i);
        }
	}

        exit(0);
}