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_REFCOUNT_ITEM_H__
7 #define __XFS_REFCOUNT_ITEM_H__
8
9 /*
10 * There are (currently) two pairs of refcount btree redo item types:
11 * increase and decrease. The log items for these are CUI (refcount
12 * update intent) and CUD (refcount update done). The redo item type
13 * is encoded in the 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
17 * transaction that records the associated refcountbt updates.
18 *
19 * Should the system crash after the commit of the first transaction
20 * but before the commit of the final transaction in a series, log
21 * recovery will use the redo information recorded by the intent items
22 * to replay the refcountbt metadata updates.
23 */
24
25 /* kernel only CUI/CUD 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_CUI_MAX_FAST_EXTENTS 16
34
35 /*
36 * This is the "refcount update intent" log item. It is used to log
37 * the fact that some reverse mappings need to change. It is used in
38 * conjunction with the "refcount update done" log item described
39 * below.
40 *
41 * These log items follow the same rules as struct xfs_efi_log_item;
42 * see the comments about that structure (in xfs_extfree_item.h) for
43 * more details.
44 */
45 struct xfs_cui_log_item {
46 struct xfs_log_item cui_item;
47 atomic_t cui_refcount;
48 atomic_t cui_next_extent;
49 struct xfs_cui_log_format cui_format;
50 };
51
52 static inline size_t
53 xfs_cui_log_item_sizeof(
54 unsigned int nr)
55 {
56 return offsetof(struct xfs_cui_log_item, cui_format) +
57 xfs_cui_log_format_sizeof(nr);
58 }
59
60 /*
61 * This is the "refcount update done" log item. It is used to log the
62 * fact that some refcountbt updates mentioned in an earlier cui item
63 * have been performed.
64 */
65 struct xfs_cud_log_item {
66 struct xfs_log_item cud_item;
67 struct xfs_cui_log_item *cud_cuip;
68 struct xfs_cud_log_format cud_format;
69 };
70
71 extern struct kmem_cache *xfs_cui_cache;
72 extern struct kmem_cache *xfs_cud_cache;
73
74 struct xfs_refcount_intent;
75
76 void xfs_refcount_defer_add(struct xfs_trans *tp,
77 struct xfs_refcount_intent *ri);
78
79 #endif /* __XFS_REFCOUNT_ITEM_H__ */
80
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