xref: /freebsd/sys/contrib/openzfs/module/zfs/objlist.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
1 /*
2  * CDDL HEADER START
3  *
4  * This file and its contents are supplied under the terms of the
5  * Common Development and Distribution License ("CDDL"), version 1.0.
6  * You may only use this file in accordance with the terms of version
7  * 1.0 of the CDDL.
8  *
9  * A full copy of the text of the CDDL should have accompanied this
10  * source.  A copy of the CDDL is also available via the Internet at
11  * http://www.illumos.org/license/CDDL.
12  *
13  * CDDL HEADER END
14  */
15 /*
16  * Copyright (c) 2018 by Delphix. All rights reserved.
17  */
18 
19 #include	<sys/objlist.h>
20 #include	<sys/zfs_context.h>
21 
22 objlist_t *
23 objlist_create(void)
24 {
25 	objlist_t *list = kmem_alloc(sizeof (*list), KM_SLEEP);
26 	list_create(&list->ol_list, sizeof (objlist_node_t),
27 	    offsetof(objlist_node_t, on_node));
28 	list->ol_last_lookup = 0;
29 	return (list);
30 }
31 
32 void
33 objlist_destroy(objlist_t *list)
34 {
35 	for (objlist_node_t *n = list_remove_head(&list->ol_list);
36 	    n != NULL; n = list_remove_head(&list->ol_list)) {
37 		kmem_free(n, sizeof (*n));
38 	}
39 	list_destroy(&list->ol_list);
40 	kmem_free(list, sizeof (*list));
41 }
42 
43 /*
44  * This function looks through the objlist to see if the specified object number
45  * is contained in the objlist.  In the process, it will remove all object
46  * numbers in the list that are smaller than the specified object number.  Thus,
47  * any lookup of an object number smaller than a previously looked up object
48  * number will always return false; therefore, all lookups should be done in
49  * ascending order.
50  */
51 boolean_t
52 objlist_exists(objlist_t *list, uint64_t object)
53 {
54 	objlist_node_t *node = list_head(&list->ol_list);
55 	ASSERT3U(object, >=, list->ol_last_lookup);
56 	list->ol_last_lookup = object;
57 	while (node != NULL && node->on_object < object) {
58 		VERIFY3P(node, ==, list_remove_head(&list->ol_list));
59 		kmem_free(node, sizeof (*node));
60 		node = list_head(&list->ol_list);
61 	}
62 	return (node != NULL && node->on_object == object);
63 }
64 
65 /*
66  * The objlist is a list of object numbers stored in ascending order.  However,
67  * the insertion of new object numbers does not seek out the correct location to
68  * store a new object number; instead, it appends it to the list for simplicity.
69  * Thus, any users must take care to only insert new object numbers in ascending
70  * order.
71  */
72 void
73 objlist_insert(objlist_t *list, uint64_t object)
74 {
75 	objlist_node_t *node = kmem_zalloc(sizeof (*node), KM_SLEEP);
76 	node->on_object = object;
77 #ifdef ZFS_DEBUG
78 	objlist_node_t *last_object = list_tail(&list->ol_list);
79 	uint64_t last_objnum = (last_object != NULL ? last_object->on_object :
80 	    0);
81 	ASSERT3U(node->on_object, >, last_objnum);
82 #endif
83 	list_insert_tail(&list->ol_list, node);
84 }
85