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_BMAP_ITEM_H__
7 #define __XFS_BMAP_ITEM_H__
8
9 /*
10 * There are (currently) two pairs of bmap btree redo item types: map & unmap.
11 * The common abbreviations for these are BUI (bmap update intent) and BUD
12 * (bmap update done). The redo item type is encoded in the flags field of
13 * 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 bmbt updates.
18 *
19 * Should the system crash after the commit of the first transaction but
20 * before the commit of the final transaction in a series, log recovery will
21 * use the redo information recorded by the intent items to replay the
22 * bmbt metadata updates in the non-first transaction.
23 */
24
25 /* kernel only BUI/BUD definitions */
26
27 struct xfs_mount;
28 struct kmem_cache;
29
30 /*
31 * Max number of extents in fast allocation path.
32 */
33 #define XFS_BUI_MAX_FAST_EXTENTS 1
34
35 /*
36 * This is the "bmap update intent" log item. It is used to log the fact that
37 * some reverse mappings need to change. It is used in conjunction with the
38 * "bmap update done" log item described below.
39 *
40 * These log items follow the same rules as struct xfs_efi_log_item; see the
41 * comments about that structure (in xfs_extfree_item.h) for more details.
42 */
43 struct xfs_bui_log_item {
44 struct xfs_log_item bui_item;
45 atomic_t bui_refcount;
46 atomic_t bui_next_extent;
47 struct xfs_bui_log_format bui_format;
48 };
49
50 static inline size_t
51 xfs_bui_log_item_sizeof(
52 unsigned int nr)
53 {
54 return offsetof(struct xfs_bui_log_item, bui_format) +
55 xfs_bui_log_format_sizeof(nr);
56 }
57
58 /*
59 * This is the "bmap update done" log item. It is used to log the fact that
60 * some bmbt updates mentioned in an earlier bui item have been performed.
61 */
62 struct xfs_bud_log_item {
63 struct xfs_log_item bud_item;
64 struct xfs_bui_log_item *bud_buip;
65 struct xfs_bud_log_format bud_format;
66 };
67
68 extern struct kmem_cache *xfs_bui_cache;
69 extern struct kmem_cache *xfs_bud_cache;
70
71 struct xfs_bmap_intent;
72
73 void xfs_bmap_defer_add(struct xfs_trans *tp, struct xfs_bmap_intent *bi);
74
75 #endif /* __XFS_BMAP_ITEM_H__ */
76
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