1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2016 Oracle.  All Rights Reserved.
4 * Author: Darrick J. Wong <darrick.wong@oracle.com>
5 */
6#ifndef	__XFS_RMAP_ITEM_H__
7#define	__XFS_RMAP_ITEM_H__
8
9/*
10 * There are (currently) three pairs of rmap btree redo item types: map, unmap,
11 * and convert.  The common abbreviations for these are RUI (rmap update
12 * intent) and RUD (rmap update done).  The redo item type is encoded in the
13 * flags field of each xfs_map_extent.
14 *
15 * *I items should be recorded in the *first* of a series of rolled
16 * transactions, and the *D items should be recorded in the same transaction
17 * that records the associated rmapbt updates.  Typically, the first
18 * transaction will record a bmbt update, followed by some number of
19 * transactions containing rmapbt updates, and finally transactions with any
20 * bnobt/cntbt updates.
21 *
22 * Should the system crash after the commit of the first transaction but
23 * before the commit of the final transaction in a series, log recovery will
24 * use the redo information recorded by the intent items to replay the
25 * (rmapbt/bnobt/cntbt) metadata updates in the non-first transaction.
26 */
27
28/* kernel only RUI/RUD definitions */
29
30struct xfs_mount;
31struct kmem_cache;
32
33/*
34 * Max number of extents in fast allocation path.
35 */
36#define	XFS_RUI_MAX_FAST_EXTENTS	16
37
38/*
39 * This is the "rmap update intent" log item.  It is used to log the fact that
40 * some reverse mappings need to change.  It is used in conjunction with the
41 * "rmap update done" log item described below.
42 *
43 * These log items follow the same rules as struct xfs_efi_log_item; see the
44 * comments about that structure (in xfs_extfree_item.h) for more details.
45 */
46struct xfs_rui_log_item {
47	struct xfs_log_item		rui_item;
48	atomic_t			rui_refcount;
49	atomic_t			rui_next_extent;
50	struct xfs_rui_log_format	rui_format;
51};
52
53static inline size_t
54xfs_rui_log_item_sizeof(
55	unsigned int		nr)
56{
57	return offsetof(struct xfs_rui_log_item, rui_format) +
58			xfs_rui_log_format_sizeof(nr);
59}
60
61/*
62 * This is the "rmap update done" log item.  It is used to log the fact that
63 * some rmapbt updates mentioned in an earlier rui item have been performed.
64 */
65struct xfs_rud_log_item {
66	struct xfs_log_item		rud_item;
67	struct xfs_rui_log_item		*rud_ruip;
68	struct xfs_rud_log_format	rud_format;
69};
70
71extern struct kmem_cache	*xfs_rui_cache;
72extern struct kmem_cache	*xfs_rud_cache;
73
74#endif	/* __XFS_RMAP_ITEM_H__ */
75