1 files changed, 84 insertions, 0 deletions
diff --git a/module/zfs/objlist.c b/module/zfs/objlist.c
new file mode 100644
index 000000000..c80bab2a7
--- /dev/null
+++ b/module/zfs/objlist.c
@@ -0,0 +1,84 @@
+/*
+ * CDDL HEADER START
+ *
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2018 by Delphix. All rights reserved.
+ */
+
+#include	<sys/objlist.h>
+#include	<sys/zfs_context.h>
+
+objlist_t *
+objlist_create(void)
+{
+	objlist_t *list = kmem_alloc(sizeof (*list), KM_SLEEP);
+	list_create(&list->ol_list, sizeof (objlist_node_t),
+	    offsetof(objlist_node_t, on_node));
+	list->ol_last_lookup = 0;
+	return (list);
+}
+
+void
+objlist_destroy(objlist_t *list)
+{
+	for (objlist_node_t *n = list_remove_head(&list->ol_list);
+	    n != NULL; n = list_remove_head(&list->ol_list)) {
+		kmem_free(n, sizeof (*n));
+	}
+	list_destroy(&list->ol_list);
+	kmem_free(list, sizeof (*list));
+}
+
+/*
+ * This function looks through the objlist to see if the specified object number
+ * is contained in the objlist.  In the process, it will remove all object
+ * numbers in the list that are smaller than the specified object number.  Thus,
+ * any lookup of an object number smaller than a previously looked up object
+ * number will always return false; therefore, all lookups should be done in
+ * ascending order.
+ */
+boolean_t
+objlist_exists(objlist_t *list, uint64_t object)
+{
+	objlist_node_t *node = list_head(&list->ol_list);
+	ASSERT3U(object, >=, list->ol_last_lookup);
+	list->ol_last_lookup = object;
+	while (node != NULL && node->on_object < object) {
+		VERIFY3P(node, ==, list_remove_head(&list->ol_list));
+		kmem_free(node, sizeof (*node));
+		node = list_head(&list->ol_list);
+	}
+	return (node != NULL && node->on_object == object);
+}
+
+/*
+ * The objlist is a list of object numbers stored in ascending order.  However,
+ * the insertion of new object numbers does not seek out the correct location to
+ * store a new object number; instead, it appends it to the list for simplicity.
+ * Thus, any users must take care to only insert new object numbers in ascending
+ * order.
+ */
+void
+objlist_insert(objlist_t *list, uint64_t object)
+{
+	objlist_node_t *node = kmem_zalloc(sizeof (*node), KM_SLEEP);
+	node->on_object = object;
+#ifdef ZFS_DEBUG
+	objlist_node_t *last_object = list_tail(&list->ol_list);
+	uint64_t last_objnum = (last_object != NULL ? last_object->on_object :
+	    0);
+	ASSERT3U(node->on_object, >, last_objnum);
+#endif
+	list_insert_tail(&list->ol_list, node);
+}