File tmpDir = Util.createTempDir();
// mount a new file system to a temporary location
out.println("Opening "+target);
ZFSFileSystem hudson = zfs.open(target, ZFSFileSystem.class);
hudson.setMountPoint(tmpDir);
hudson.setProperty("hudson:managed-by","hudson"); // mark this file system as "managed by Hudson"
hudson.mount();
// copy all the files