Hi.
I just reproduced a problem I was chasing on FreeBSD also on
OpenSolaris from around 2008.01.
Simply doing something like this:
write 9k of random data into 'foo' file
truncate 'foo' file to 7k
truncate 'foo' file to 11k
read data between 7k-9k
There should be all zeros between 7k-9k, but there is previous data.
It worked fine on an older ZFS versions (I'm sure it works on version 6).
Simple test program:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <err.h>
static char buf0[9 * 1024], buf1[2 * 1024];
int
main(int argc, char *argv[])
{
int fd, i;
if (argc != 2)
errx(1, "usage: trunctest <filename>");
fd = open(argv[1], O_RDWR | O_CREAT | O_TRUNC, 0600);
if (fd == -1)
err(1, "open(%s)", argv[1]);
memset(buf0, 'x', sizeof(buf0));
if (write(fd, buf0, sizeof(buf0)) != sizeof(buf0))
err(1, "write()");
if (ftruncate(fd, 7 * 1024) == -1)
err(1, "ftruncate(%d)", 7 * 1024);
if (ftruncate(fd, 11 * 1024) == -1)
err(1, "ftruncate(%d)", 11 * 1024);
if (pread(fd, buf1, sizeof(buf1), 7 * 1024) != sizeof(buf1))
err(1, "pread()");
for (i = 0; i < sizeof(buf1); i++) {
if (buf1[i] != '\0')
errx(2, "unexpected data at %jd!", (intmax_t)(7 * 1024
+ i));
}
exit(0);
}
--
Pawel Jakub Dawidek http://www.wheel.pl
pjd at FreeBSD.org http://www.FreeBSD.org
FreeBSD committer Am I Evil? Yes, I Am!
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