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
30 struct xfs_mount;
31 struct 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 */
46 struct 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
53 static inline size_t
54 xfs_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 */
65 struct 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
71 extern struct kmem_cache *xfs_rui_cache;
72 extern struct kmem_cache *xfs_rud_cache;
73
74 struct xfs_rmap_intent;
75
76 void xfs_rmap_defer_add(struct xfs_trans *tp, struct xfs_rmap_intent *ri);
77
78 #endif /* __XFS_RMAP_ITEM_H__ */
79
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