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_RMAP_ITEM_H__
7 #define	__XFS_RMAP_ITEM_H__
8 
9 /*
10  * There are (currently) three pairs of rmap btree redo item types: map, unmap,
11  * and convert.  The common abbreviations for these are RUI (rmap update
12  * intent) and RUD (rmap update done).  The redo item type is encoded in the
13  * 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 transaction
17  * that records the associated rmapbt updates.  Typically, the first
18  * transaction will record a bmbt update, followed by some number of
19  * transactions containing rmapbt updates, and finally transactions with any
20  * bnobt/cntbt updates.
21  *
22  * Should the system crash after the commit of the first transaction but
23  * before the commit of the final transaction in a series, log recovery will
24  * use the redo information recorded by the intent items to replay the
25  * (rmapbt/bnobt/cntbt) metadata updates in the non-first transaction.
26  */
27 
28 /* kernel only RUI/RUD definitions */
29 
30 struct xfs_mount;
31 struct kmem_zone;
32 
33 /*
34  * Max number of extents in fast allocation path.
35  */
36 #define	XFS_RUI_MAX_FAST_EXTENTS	16
37 
38 /*
39  * Define RUI flag bits. Manipulated by set/clear/test_bit operators.
40  */
41 #define	XFS_RUI_RECOVERED		1
42 
43 /*
44  * This is the "rmap update intent" log item.  It is used to log the fact that
45  * some reverse mappings need to change.  It is used in conjunction with the
46  * "rmap update done" log item described below.
47  *
48  * These log items follow the same rules as struct xfs_efi_log_item; see the
49  * comments about that structure (in xfs_extfree_item.h) for more details.
50  */
51 struct xfs_rui_log_item {
52 	struct xfs_log_item		rui_item;
53 	atomic_t			rui_refcount;
54 	atomic_t			rui_next_extent;
55 	unsigned long			rui_flags;	/* misc flags */
56 	struct xfs_rui_log_format	rui_format;
57 };
58 
59 static inline size_t
xfs_rui_log_item_sizeof(unsigned int nr)60 xfs_rui_log_item_sizeof(
61 	unsigned int		nr)
62 {
63 	return offsetof(struct xfs_rui_log_item, rui_format) +
64 			xfs_rui_log_format_sizeof(nr);
65 }
66 
67 /*
68  * This is the "rmap update done" log item.  It is used to log the fact that
69  * some rmapbt updates mentioned in an earlier rui item have been performed.
70  */
71 struct xfs_rud_log_item {
72 	struct xfs_log_item		rud_item;
73 	struct xfs_rui_log_item		*rud_ruip;
74 	struct xfs_rud_log_format	rud_format;
75 };
76 
77 extern struct kmem_zone	*xfs_rui_zone;
78 extern struct kmem_zone	*xfs_rud_zone;
79 
80 struct xfs_rui_log_item *xfs_rui_init(struct xfs_mount *, uint);
81 struct xfs_rud_log_item *xfs_rud_init(struct xfs_mount *,
82 		struct xfs_rui_log_item *);
83 int xfs_rui_copy_format(struct xfs_log_iovec *buf,
84 		struct xfs_rui_log_format *dst_rui_fmt);
85 void xfs_rui_item_free(struct xfs_rui_log_item *);
86 void xfs_rui_release(struct xfs_rui_log_item *);
87 int xfs_rui_recover(struct xfs_mount *mp, struct xfs_rui_log_item *ruip);
88 
89 #endif	/* __XFS_RMAP_ITEM_H__ */
90