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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_zone;
29 
30 /*
31  * Max number of extents in fast allocation path.
32  */
33 #define	XFS_CUI_MAX_FAST_EXTENTS	16
34 
35 /*
36  * Define CUI flag bits. Manipulated by set/clear/test_bit operators.
37  */
38 #define	XFS_CUI_RECOVERED		1
39 
40 /*
41  * This is the "refcount update intent" log item.  It is used to log
42  * the fact that some reverse mappings need to change.  It is used in
43  * conjunction with the "refcount update done" log item described
44  * below.
45  *
46  * These log items follow the same rules as struct xfs_efi_log_item;
47  * see the comments about that structure (in xfs_extfree_item.h) for
48  * more details.
49  */
50 struct xfs_cui_log_item {
51 	struct xfs_log_item		cui_item;
52 	atomic_t			cui_refcount;
53 	atomic_t			cui_next_extent;
54 	unsigned long			cui_flags;	/* misc flags */
55 	struct xfs_cui_log_format	cui_format;
56 };
57 
58 static inline size_t
xfs_cui_log_item_sizeof(unsigned int nr)59 xfs_cui_log_item_sizeof(
60 	unsigned int		nr)
61 {
62 	return offsetof(struct xfs_cui_log_item, cui_format) +
63 			xfs_cui_log_format_sizeof(nr);
64 }
65 
66 /*
67  * This is the "refcount update done" log item.  It is used to log the
68  * fact that some refcountbt updates mentioned in an earlier cui item
69  * have been performed.
70  */
71 struct xfs_cud_log_item {
72 	struct xfs_log_item		cud_item;
73 	struct xfs_cui_log_item		*cud_cuip;
74 	struct xfs_cud_log_format	cud_format;
75 };
76 
77 extern struct kmem_zone	*xfs_cui_zone;
78 extern struct kmem_zone	*xfs_cud_zone;
79 
80 struct xfs_cui_log_item *xfs_cui_init(struct xfs_mount *, uint);
81 void xfs_cui_item_free(struct xfs_cui_log_item *);
82 void xfs_cui_release(struct xfs_cui_log_item *);
83 int xfs_cui_recover(struct xfs_trans *parent_tp, struct xfs_cui_log_item *cuip);
84 
85 #endif	/* __XFS_REFCOUNT_ITEM_H__ */
86