xref: /linux/fs/jfs/jfs_btree.h (revision 75bf465f0bc33e9b776a46d6a1b9b990f5fb7c37)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  *   Copyright (C) International Business Machines Corp., 2000-2004
4  */
5 #ifndef	_H_JFS_BTREE
6 #define _H_JFS_BTREE
7 
8 /*
9  *	jfs_btree.h: B+-tree
10  *
11  * JFS B+-tree (dtree and xtree) common definitions
12  */
13 
14 /*
15  *	basic btree page - btpage
16  *
17 struct btpage {
18 	s64 next;		right sibling bn
19 	s64 prev;		left sibling bn
20 
21 	u8 flag;
22 	u8 rsrvd[7];		type specific
23 	s64 self;		self address
24 
25 	u8 entry[4064];
26 };						*/
27 
28 /* btpaget_t flag */
29 #define BT_TYPE		0x07	/* B+-tree index */
30 #define	BT_ROOT		0x01	/* root page */
31 #define	BT_LEAF		0x02	/* leaf page */
32 #define	BT_INTERNAL	0x04	/* internal page */
33 #define	BT_RIGHTMOST	0x10	/* rightmost page */
34 #define	BT_LEFTMOST	0x20	/* leftmost page */
35 #define	BT_SWAPPED	0x80	/* used by fsck for endian swapping */
36 
37 /* btorder (in inode) */
38 #define	BT_RANDOM		0x0000
39 #define	BT_SEQUENTIAL		0x0001
40 #define	BT_LOOKUP		0x0010
41 #define	BT_INSERT		0x0020
42 #define	BT_DELETE		0x0040
43 
44 /*
45  *	btree page buffer cache access
46  */
47 #define BT_IS_ROOT(MP) (((MP)->xflag & COMMIT_PAGE) == 0)
48 
49 /* get page from buffer page */
50 #define BT_PAGE(IP, MP, TYPE, ROOT)\
51 	(BT_IS_ROOT(MP) ? (TYPE *)&JFS_IP(IP)->ROOT : (TYPE *)(MP)->data)
52 
53 /* get the page buffer and the page for specified block address */
54 #define BT_GETPAGE(IP, BN, MP, TYPE, SIZE, P, RC, ROOT)\
55 {\
56 	if ((BN) == 0)\
57 	{\
58 		MP = (struct metapage *)&JFS_IP(IP)->bxflag;\
59 		P = (TYPE *)&JFS_IP(IP)->ROOT;\
60 		RC = 0;\
61 	}\
62 	else\
63 	{\
64 		MP = read_metapage((IP), BN, SIZE, 1);\
65 		if (MP) {\
66 			RC = 0;\
67 			P = (MP)->data;\
68 		} else {\
69 			P = NULL;\
70 			jfs_err("bread failed!");\
71 			RC = -EIO;\
72 		}\
73 	}\
74 }
75 
76 #define BT_MARK_DIRTY(MP, IP)\
77 {\
78 	if (BT_IS_ROOT(MP))\
79 		mark_inode_dirty(IP);\
80 	else\
81 		mark_metapage_dirty(MP);\
82 }
83 
84 /* put the page buffer */
85 #define BT_PUTPAGE(MP)\
86 {\
87 	if (! BT_IS_ROOT(MP)) \
88 		release_metapage(MP); \
89 }
90 
91 
92 /*
93  *	btree traversal stack
94  *
95  * record the path traversed during the search;
96  * top frame record the leaf page/entry selected.
97  */
98 struct btframe {	/* stack frame */
99 	s64 bn;			/* 8: */
100 	s16 index;		/* 2: */
101 	s16 lastindex;		/* 2: unused */
102 	struct metapage *mp;	/* 4/8: */
103 };				/* (16/24) */
104 
105 struct btstack {
106 	struct btframe *top;
107 	int nsplit;
108 	struct btframe stack[MAXTREEHEIGHT];
109 };
110 
111 #define BT_CLR(btstack)\
112 	(btstack)->top = (btstack)->stack
113 
114 #define BT_STACK_FULL(btstack)\
115 	( (btstack)->top == &((btstack)->stack[MAXTREEHEIGHT-1]))
116 
117 #define BT_PUSH(BTSTACK, BN, INDEX)\
118 {\
119 	assert(!BT_STACK_FULL(BTSTACK));\
120 	(BTSTACK)->top->bn = BN;\
121 	(BTSTACK)->top->index = INDEX;\
122 	++(BTSTACK)->top;\
123 }
124 
125 #define BT_POP(btstack)\
126 	( (btstack)->top == (btstack)->stack ? NULL : --(btstack)->top )
127 
128 #define BT_STACK(btstack)\
129 	( (btstack)->top == (btstack)->stack ? NULL : (btstack)->top )
130 
BT_STACK_DUMP(struct btstack * btstack)131 static inline void BT_STACK_DUMP(struct btstack *btstack)
132 {
133 	int i;
134 	printk("btstack dump:\n");
135 	for (i = 0; i < MAXTREEHEIGHT; i++)
136 		printk(KERN_ERR "bn = %Lx, index = %d\n",
137 		       (long long)btstack->stack[i].bn,
138 		       btstack->stack[i].index);
139 }
140 
141 /* retrieve search results */
142 #define BT_GETSEARCH(IP, LEAF, BN, MP, TYPE, P, INDEX, ROOT)\
143 {\
144 	BN = (LEAF)->bn;\
145 	MP = (LEAF)->mp;\
146 	if (BN)\
147 		P = (TYPE *)MP->data;\
148 	else\
149 		P = (TYPE *)&JFS_IP(IP)->ROOT;\
150 	INDEX = (LEAF)->index;\
151 }
152 
153 /* put the page buffer of search */
154 #define BT_PUTSEARCH(BTSTACK)\
155 {\
156 	if (! BT_IS_ROOT((BTSTACK)->top->mp))\
157 		release_metapage((BTSTACK)->top->mp);\
158 }
159 #endif				/* _H_JFS_BTREE */
160