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_zone;
29
30 /*
31 * Max number of extents in fast allocation path.
32 */
33 #define XFS_BUI_MAX_FAST_EXTENTS 1
34
35 /*
36 * Define BUI flag bits. Manipulated by set/clear/test_bit operators.
37 */
38 #define XFS_BUI_RECOVERED 1
39
40 /*
41 * This is the "bmap update intent" log item. It is used to log the fact that
42 * some reverse mappings need to change. It is used in conjunction with the
43 * "bmap update done" log item described below.
44 *
45 * These log items follow the same rules as struct xfs_efi_log_item; see the
46 * comments about that structure (in xfs_extfree_item.h) for more details.
47 */
48 struct xfs_bui_log_item {
49 struct xfs_log_item bui_item;
50 atomic_t bui_refcount;
51 atomic_t bui_next_extent;
52 unsigned long bui_flags; /* misc flags */
53 struct xfs_bui_log_format bui_format;
54 };
55
56 static inline size_t
57 xfs_bui_log_item_sizeof(
58 unsigned int nr)
59 {
60 return offsetof(struct xfs_bui_log_item, bui_format) +
61 xfs_bui_log_format_sizeof(nr);
62 }
63
64 /*
65 * This is the "bmap update done" log item. It is used to log the fact that
66 * some bmbt updates mentioned in an earlier bui item have been performed.
67 */
68 struct xfs_bud_log_item {
69 struct xfs_log_item bud_item;
70 struct xfs_bui_log_item *bud_buip;
71 struct xfs_bud_log_format bud_format;
72 };
73
74 extern struct kmem_zone *xfs_bui_zone;
75 extern struct kmem_zone *xfs_bud_zone;
76
77 struct xfs_bui_log_item *xfs_bui_init(struct xfs_mount *);
78 void xfs_bui_item_free(struct xfs_bui_log_item *);
79 void xfs_bui_release(struct xfs_bui_log_item *);
80 int xfs_bui_recover(struct xfs_trans *parent_tp, struct xfs_bui_log_item *buip);
81
82 #endif /* __XFS_BMAP_ITEM_H__ */