Merge pull request #96396 from marosset/windows-smb-mount-symlink-fix

fixing issue where SMB share paths cannot resolve with CRI-containerD on Windows

staging/src/k8s.io/mount-utils/mount_windows.go

@@ -132,12 +132,23 @@ func (mounter *Mounter) MountSensitive(source string, target string, fstype stri
 		}
 	}
 
-	output, err := exec.Command("cmd", "/c", "mklink", "/D", target, bindSource).CombinedOutput()
+	// There is an issue in golang where EvalSymlinks fails on Windows when passed a
+	// UNC share root path without a trailing backslash.
+	// Ex: \\SERVER\share will fail to resolve but \\SERVER\share\ will resolve
+	// containerD on Windows calls EvalSymlinks so we'll add the backslash when making the symlink if it is missing.
+	// https://github.com/golang/go/pull/42096 fixes this issue in golang but a fix will not be available until
+	// golang v1.16
+	mklinkSource := bindSource
+	if !strings.HasSuffix(mklinkSource, "\\") {
+		mklinkSource = mklinkSource + "\\"
+	}
+
+	output, err := exec.Command("cmd", "/c", "mklink", "/D", target, mklinkSource).CombinedOutput()
 	if err != nil {
-		klog.Errorf("mklink failed: %v, source(%q) target(%q) output: %q", err, bindSource, target, string(output))
+		klog.Errorf("mklink failed: %v, source(%q) target(%q) output: %q", err, mklinkSource, target, string(output))
 		return err
 	}
-	klog.V(2).Infof("mklink source(%q) on target(%q) successfully, output: %q", bindSource, target, string(output))
+	klog.V(2).Infof("mklink source(%q) on target(%q) successfully, output: %q", mklinkSource, target, string(output))
 
 	return nil
 }