diff --git a/Makefile b/Makefile
index 67ebde1..bc28b24 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ RELEASE=2.0
 
 VERSION=2.0
 PACKAGE=libpve-storage-perl
-PKGREL=17
+PKGREL=18
 
 DESTDIR=
 PREFIX=/usr
diff --git a/PVE/Storage.pm b/PVE/Storage.pm
index 4148ed3..c78bac6 100755
--- a/PVE/Storage.pm
+++ b/PVE/Storage.pm
@@ -1018,7 +1018,9 @@ sub path_to_volume_id {
 	return ('');
     }
 
-    $path = abs_path ($path);
+    # Note: abs_path() return undef if $path doesn not exist 
+    # for example when nfs storage is not mounted
+    $path = abs_path($path) || $path;
 
     foreach my $sid (keys %$ids) {
 	my $type = $ids->{$sid}->{type};
diff --git a/changelog.Debian b/changelog.Debian
index 9f21ff3..cae22a9 100644
--- a/changelog.Debian
+++ b/changelog.Debian
@@ -1,3 +1,9 @@
+libpve-storage-perl (2.0-18) unstable; urgency=low
+
+  * fix bug #171: fix path_to_volume_id for unmounted NFS
+
+ -- Proxmox Support Team <support@proxmox.com>  Wed, 18 Apr 2012 12:34:11 +0200
+
 libpve-storage-perl (2.0-17) unstable; urgency=low
 
   * fix bug #148: set maxfiles for default local storage