posix: use nanosecond accuracy when available

Programs that set mtime, such as `rsync -a`, don't work correctly on
GlusterFS, because it sets the nanoseconds to 000. This creates
problems for incremental backups, where files get accidentally copied
again and again.

For example, consider `myfile` on an ext4 system, being copied to a
GlusterFS volume, with `rsync -a` and then `cp -u` in turn. You'd
expect that after the first `rsync -a`, `cp -u` agrees that the file
need not be copied.

BUG: 1422074
Change-Id: I89c7b6a73e2e06c02851ff76b7e5cdfaa271e985
Signed-off-by: Niklas Hambüchen <mail@nh2.me>
Reviewed-on: https://review.gluster.org/16667
Smoke: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Tested-by: Jeff Darcy <jdarcy@redhat.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: jiffin tony Thottan <jthottan@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/libglusterfs/src/syscall.c b/libglusterfs/src/syscall.c
index 4e4c6a728da..a7d4402808d 100644
--- a/libglusterfs/src/syscall.c
+++ b/libglusterfs/src/syscall.c
@@ -272,6 +272,16 @@ sys_utimes (const char *filename, const struct timeval times[2])
 }
 
 
+#if defined(HAVE_UTIMENSAT)
+int
+sys_utimensat (int dirfd, const char *filename, const struct timespec times[2],
+               int flags)
+{
+        return utimensat (dirfd, filename, times, flags);
+}
+#endif
+
+
 int
 sys_creat (const char *pathname, mode_t mode)
 {