loopback: Utimens: enable Nsec precision for dates after 1970

fuse/misc.go

@@ -12,6 +12,7 @@ import (
 	"os"
 	"reflect"
 	"syscall"
+	"time"
 	"unsafe"
 )
 
@@ -86,3 +87,21 @@ func init() {
 		log.Panicf("page size incorrect: %d", p)
 	}
 }
+
+const _UTIME_OMIT = ((1 << 30) - 2)
+
+// UtimeToTimespec converts a "Time" pointer as passed to Utimens to a
+// "Timespec" that can be passed to the utimensat syscall.
+// A nil pointer is converted to the special UTIME_OMIT value.
+func UtimeToTimespec(t *time.Time) (ts syscall.Timespec) {
+	if t == nil {
+		ts.Nsec = _UTIME_OMIT
+	} else {
+		ts = syscall.NsecToTimespec(t.UnixNano())
+		// Go bug https://github.com/golang/go/issues/12777
+		if ts.Nsec < 0 {
+			ts.Nsec = 0
+		}
+	}
+	return ts
+}

fuse/nodefs/files_darwin.go

@@ -65,7 +65,6 @@ func (f *loopbackFile) Allocate(off uint64, sz uint64, mode uint32) fuse.Status
 	return fuse.OK
 }
 
-const _UTIME_NOW = ((1 << 30) - 1)
 const _UTIME_OMIT = ((1 << 30) - 2)
 
 // timeToTimeval - Convert time.Time to syscall.Timeval

fuse/nodefs/files_linux.go

@@ -21,27 +21,11 @@ func (f *loopbackFile) Allocate(off uint64, sz uint64, mode uint32) fuse.Status
 	return fuse.OK
 }
 
-const _UTIME_NOW = ((1 << 30) - 1)
-const _UTIME_OMIT = ((1 << 30) - 2)
-
 // Utimens - file handle based version of loopbackFileSystem.Utimens()
 func (f *loopbackFile) Utimens(a *time.Time, m *time.Time) fuse.Status {
 	var ts [2]syscall.Timespec
-
-	if a == nil {
-		ts[0].Nsec = _UTIME_OMIT
-	} else {
-		ts[0] = syscall.NsecToTimespec(a.UnixNano())
-		ts[0].Nsec = 0
-	}
-
-	if m == nil {
-		ts[1].Nsec = _UTIME_OMIT
-	} else {
-		ts[1] = syscall.NsecToTimespec(a.UnixNano())
-		ts[1].Nsec = 0
-	}
-
+	ts[0] = fuse.UtimeToTimespec(a)
+	ts[1] = fuse.UtimeToTimespec(m)
 	f.lock.Lock()
 	err := futimens(int(f.File.Fd()), &ts)
 	f.lock.Unlock()

fuse/pathfs/loopback_linux.go

@@ -39,27 +39,11 @@ func (fs *loopbackFileSystem) SetXAttr(name string, attr string, data []byte, fl
 	return fuse.ToStatus(err)
 }
 
-const _UTIME_NOW = ((1 << 30) - 1)
-const _UTIME_OMIT = ((1 << 30) - 2)
-
 // Utimens - path based version of loopbackFile.Utimens()
 func (fs *loopbackFileSystem) Utimens(path string, a *time.Time, m *time.Time, context *fuse.Context) (code fuse.Status) {
 	var ts [2]syscall.Timespec
-
-	if a == nil {
-		ts[0].Nsec = _UTIME_OMIT
-	} else {
-		ts[0] = syscall.NsecToTimespec(a.UnixNano())
-		ts[0].Nsec = 0
-	}
-
-	if m == nil {
-		ts[1].Nsec = _UTIME_OMIT
-	} else {
-		ts[1] = syscall.NsecToTimespec(m.UnixNano())
-		ts[1].Nsec = 0
-	}
-
+	ts[0] = fuse.UtimeToTimespec(a)
+	ts[1] = fuse.UtimeToTimespec(m)
 	err := sysUtimensat(0, fs.GetPath(path), &ts, _AT_SYMLINK_NOFOLLOW)
 	return fuse.ToStatus(err)
 }

fuse/test/loopback_linux_test.go

@@ -70,6 +70,41 @@ func TestNegativeTime(t *testing.T) {
 	}
 }
 
+// Setting nanoseconds should work for dates after 1970
+func TestUtimesNano(t *testing.T) {
+	tc := NewTestCase(t)
+	defer tc.Cleanup()
+
+	path := tc.mountFile
+	err := ioutil.WriteFile(path, []byte("xyz"), 0600)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ts := make([]syscall.Timespec, 2)
+	// atime
+	ts[0].Sec = 1
+	ts[0].Nsec = 2
+	// mtime
+	ts[1].Sec = 3
+	ts[1].Nsec = 4
+	err = syscall.UtimesNano(path, ts)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var st syscall.Stat_t
+	err = syscall.Stat(path, &st)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if st.Atim != ts[0] {
+		t.Errorf("Wrong atime: %v, want: %v", st.Atim, ts[0])
+	}
+	if st.Mtim != ts[1] {
+		t.Errorf("Wrong mtime: %v, want: %v", st.Mtim, ts[1])
+	}
+}
+
 func clearStatfs(s *syscall.Statfs_t) {
 	empty := syscall.Statfs_t{}
 	s.Type = 0