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 | #endif /* __XFS_BMAP_ITEM_H__ */ |
72 | |