Date: Sun, 30 Nov 2014 10:07:20 +1000 From: Paul Koch <paul.koch137@gmail.com> To: freebsd-stable@freebsd.org Subject: Re: 10.1 mmap on zfs not updating mtime Message-ID: <20141130100720.5b0bead7@splash.akips.com> In-Reply-To: <20141125142302.1199041c@akips.com> References: <20141125142302.1199041c@akips.com>
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Can probably ignore this. We changed our application so it always calls
futimes() on the file descriptor after a fsync() or munmap().
Paul.
On Tue, 25 Nov 2014 14:23:02 +1000
Paul Koch <paul.koch@akips.com> wrote:
>
> 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.
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