#!/bin/sh # # Copyright (c) 2011 Peter Holm # 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. # [ `id -u ` -ne 0 ] && echo "Must be root!" && exit 1 # Demonstrate rename(2) cache problem, where the original name lingers in the VFS cache. # Original test scenario by Anton Yuzhaninov . ../default.cfg here=`pwd` cd /tmp sed '1,/^EOF/d' < $here/$0 > rename6.c mycc -o rename6 -Wall -Wextra -O2 rename6.c rm -f rename6.c cd $here mount | grep $mntpoint | grep -q /dev/md && umount -f $mntpoint mdconfig -l | grep -q md$mdstart && mdconfig -d -u $mdstart mdconfig -a -t swap -s 2g -u $mdstart newfs $newfs_flags md$mdstart > /dev/null mount /dev/md$mdstart $mntpoint chmod 777 $mntpoint su $testuser -c "cd $mntpoint; /tmp/rename6" while mount | grep -q md$mdstart; do umount $mntpoint || sleep 1 done mdconfig -d -u $mdstart rm -f /tmp/rename6 exit EOF #include #include #include #include #include #include #include #include #include #include #include #include #include #include pid_t spid; const char *logfile = "test.log"; void cleanup() { if (kill(spid, SIGINT) == -1 && errno != ESRCH) err(1, "kill(%d)", spid); } static void Stat() { struct stat sb; int i; setproctitle("Stat"); for (;;) { for (i = 0; i < 1000; i++) { stat(logfile, &sb); } usleep(1000); } } int main(void) { struct stat sb1, sb2; int fd, i; char new[128]; if ((spid = fork()) == 0) Stat(); setproctitle("main"); atexit(cleanup); for (i = 0; i < 20000; i++) { sprintf(new, "test.log.%05d", i); if ((fd = open(logfile, O_RDWR | O_CREAT | O_TRUNC, 0644)) == -1) err(1, "creat(%s)", logfile); close(fd); #if 1 if (rename(logfile, new) == -1) warn("rename(%s, %s)", logfile, new); #else /* No cache problem is seen */ if (link(logfile, new) == -1) err(1, "link(%s, %s)", logfile, new); if (unlink(logfile) == -1) err(1, "unlink(%s)", logfile); #endif /* * stat() for logfile and new will be identical sometimes, * but only when Stat() is running. */ if (stat(logfile, &sb1) == 0 && stat(new, &sb2) == 0 && bcmp(&sb1, &sb2, sizeof(sb1)) == 0) { fprintf(stderr, "At loop #%d\n", i); fprintf(stderr, "%-15s: ino = %ju, nlink = %ju," " size = %jd\n", logfile, (uintmax_t)sb1.st_ino, (uintmax_t)sb1.st_nlink, sb1.st_blocks); fprintf(stderr, "%-15s: ino = %ju, nlink = %ju, " "size = %jd\n", new , (uintmax_t)sb2.st_ino, (uintmax_t)sb2.st_nlink, sb2.st_blocks); } unlink(new); } kill(spid, SIGINT); wait(NULL); return (0); }