+/*
+ * Determine the objset id for a given snapshot name.
+ */
+int
+dmu_snapshot_id(objset_t *os, const char *snapname, uint64_t *idp)
+{
+ dsl_dataset_t *ds = os->os_dsl_dataset;
+ zap_cursor_t cursor;
+ zap_attribute_t attr;
+ int error;
+
+ if (ds->ds_phys->ds_snapnames_zapobj == 0)
+ return (ENOENT);
+
+ zap_cursor_init(&cursor, ds->ds_dir->dd_pool->dp_meta_objset,
+ ds->ds_phys->ds_snapnames_zapobj);
+
+ error = zap_cursor_move_to_key(&cursor, snapname, MT_EXACT);
+ if (error) {
+ zap_cursor_fini(&cursor);
+ return (error);
+ }
+
+ error = zap_cursor_retrieve(&cursor, &attr);
+ if (error) {
+ zap_cursor_fini(&cursor);
+ return (error);
+ }
+
+ *idp = attr.za_first_integer;
+ zap_cursor_fini(&cursor);
+
+ return (0);
+}
+