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
xfs_bui_log_item_sizeof(unsigned int nr)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 struct xfs_bud_log_item *xfs_bud_init(struct xfs_mount *,
79 		struct xfs_bui_log_item *);
80 void xfs_bui_item_free(struct xfs_bui_log_item *);
81 void xfs_bui_release(struct xfs_bui_log_item *);
82 int xfs_bui_recover(struct xfs_trans *parent_tp, struct xfs_bui_log_item *buip);
83 
84 #endif	/* __XFS_BMAP_ITEM_H__ */
85