Date: Tue, 25 Nov 2014 14:23:02 +1000 From: Paul Koch <paul.koch@akips.com> To: freebsd-stable@freebsd.org Subject: 10.1 mmap on zfs not updating mtime Message-ID: <20141125142302.1199041c@akips.com>
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Hi,
we have observed some odd behaviour with the mtime of a mmap'ed file
when it has been updated on a zfs pool. The mtime does not appear to
be updated. Seems to work ok on UFS.
Test program below...
On 10.0, the following works ok:
dd bs=1k if=/dev/zero of=mdata count=1
ls -lT mdata; /tmp/mmap-mtime mdata; ls -lT mdata
but on 10.1 the mtime stays at its creation time.
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
int
main (int argc, char **argv)
{
int fd,
i;
char *data,
*filename;
struct stat s;
if (argc != 2)
exit (1);
filename =argv[1];
if (stat (filename, &s) != 0) {
fprintf (stderr, "stat: %s\n", strerror (errno));
exit (1);
}
else if ((fd = open (filename, O_RDWR, 0644)) == -1) {
fprintf (stderr, "open: %s\n", strerror (errno));
exit (1);
}
else if ((data = mmap (NULL, (size_t) s.st_size,
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd, (off_t) 0)) == MAP_FAILED) {
fprintf (stderr, "mmap: %s\n", strerror (errno));
exit (1);
}
for (i = 0; i < s.st_size; i++) {
data[i] = 1;
}
munmap (data, s.st_size);
close (fd);
exit (0);
}
Paul.
--
Paul Koch | Founder, CEO
AKIPS Network Monitor
http://www.akips.com
Brisbane, Australia
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