zfs: Support foo/bar/* globs

zfs/mapping.go

@@ -64,7 +64,11 @@ func (m GlobMapping) Map(source DatasetPath) (target DatasetPath, err error) {
 	for si, sc := range source {
 		target = append(target, sc)
 		if si < len(m.PrefixPath) {
-			if sc != m.PrefixPath[si] {
+
+			compsMatch := sc == m.PrefixPath[si]
+			endOfPrefixPath := si == len(m.PrefixPath)-1 && m.PrefixPath[si] == ""
+
+			if !(compsMatch || endOfPrefixPath) {
 				err = NoMatchError
 				return
 			}

zfs/mapping_test.go

@@ -5,6 +5,27 @@ import (
 	"testing"
 )
 
+func TestGlobMappingPrefixWildcard(t *testing.T) {
+
+	m := GlobMapping{
+		PrefixPath: toDatasetPath("a/b/c/"), // TRAILING empty component!
+		TargetRoot: toDatasetPath("x/y"),
+	}
+
+	t.Logf("PrefixPath: %#v", m.PrefixPath)
+
+	var r DatasetPath
+	var err error
+
+	r, err = m.Map(toDatasetPath("a/b/c"))
+	assert.NotNil(t, err)
+
+	r, err = m.Map(toDatasetPath("a/b/c/d"))
+	assert.Nil(t, err)
+	assert.Equal(t, toDatasetPath("x/y/a/b/c/d"), r)
+
+}
+
 func TestGlobMapping(t *testing.T) {
 
 	m := GlobMapping{