1 /*
2  *   Copyright (C) International Business Machines Corp., 2000-2004
3  *
4  *   This program is free software;  you can redistribute it and/or modify
5  *   it under the terms of the GNU General Public License as published by
6  *   the Free Software Foundation; either version 2 of the License, or
7  *   (at your option) any later version.
8  *
9  *   This program is distributed in the hope that it will be useful,
10  *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
12  *   the GNU General Public License for more details.
13  *
14  *   You should have received a copy of the GNU General Public License
15  *   along with this program;  if not, write to the Free Software
16  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  */
18 #ifndef	_H_JFS_BTREE
19 #define _H_JFS_BTREE
20 
21 /*
22  *	jfs_btree.h: B+-tree
23  *
24  * JFS B+-tree (dtree and xtree) common definitions
25  */
26 
27 /*
28  *	basic btree page - btpage
29  *
30 struct btpage {
31 	s64 next;		right sibling bn
32 	s64 prev;		left sibling bn
33 
34 	u8 flag;
35 	u8 rsrvd[7];		type specific
36 	s64 self;		self address
37 
38 	u8 entry[4064];
39 };						*/
40 
41 /* btpaget_t flag */
42 #define BT_TYPE		0x07	/* B+-tree index */
43 #define	BT_ROOT		0x01	/* root page */
44 #define	BT_LEAF		0x02	/* leaf page */
45 #define	BT_INTERNAL	0x04	/* internal page */
46 #define	BT_RIGHTMOST	0x10	/* rightmost page */
47 #define	BT_LEFTMOST	0x20	/* leftmost page */
48 #define	BT_SWAPPED	0x80	/* used by fsck for endian swapping */
49 
50 /* btorder (in inode) */
51 #define	BT_RANDOM		0x0000
52 #define	BT_SEQUENTIAL		0x0001
53 #define	BT_LOOKUP		0x0010
54 #define	BT_INSERT		0x0020
55 #define	BT_DELETE		0x0040
56 
57 /*
58  *	btree page buffer cache access
59  */
60 #define BT_IS_ROOT(MP) (((MP)->xflag & COMMIT_PAGE) == 0)
61 
62 /* get page from buffer page */
63 #define BT_PAGE(IP, MP, TYPE, ROOT)\
64 	(BT_IS_ROOT(MP) ? (TYPE *)&JFS_IP(IP)->ROOT : (TYPE *)(MP)->data)
65 
66 /* get the page buffer and the page for specified block address */
67 #define BT_GETPAGE(IP, BN, MP, TYPE, SIZE, P, RC, ROOT)\
68 {\
69 	if ((BN) == 0)\
70 	{\
71 		MP = (struct metapage *)&JFS_IP(IP)->bxflag;\
72 		P = (TYPE *)&JFS_IP(IP)->ROOT;\
73 		RC = 0;\
74 	}\
75 	else\
76 	{\
77 		MP = read_metapage((IP), BN, SIZE, 1);\
78 		if (MP) {\
79 			RC = 0;\
80 			P = (MP)->data;\
81 		} else {\
82 			P = NULL;\
83 			jfs_err("bread failed!");\
84 			RC = -EIO;\
85 		}\
86 	}\
87 }
88 
89 #define BT_MARK_DIRTY(MP, IP)\
90 {\
91 	if (BT_IS_ROOT(MP))\
92 		mark_inode_dirty(IP);\
93 	else\
94 		mark_metapage_dirty(MP);\
95 }
96 
97 /* put the page buffer */
98 #define BT_PUTPAGE(MP)\
99 {\
100 	if (! BT_IS_ROOT(MP)) \
101 		release_metapage(MP); \
102 }
103 
104 
105 /*
106  *	btree traversal stack
107  *
108  * record the path traversed during the search;
109  * top frame record the leaf page/entry selected.
110  */
111 struct btframe {	/* stack frame */
112 	s64 bn;			/* 8: */
113 	s16 index;		/* 2: */
114 	s16 lastindex;		/* 2: unused */
115 	struct metapage *mp;	/* 4/8: */
116 };				/* (16/24) */
117 
118 struct btstack {
119 	struct btframe *top;
120 	int nsplit;
121 	struct btframe stack[MAXTREEHEIGHT];
122 };
123 
124 #define BT_CLR(btstack)\
125 	(btstack)->top = (btstack)->stack
126 
127 #define BT_STACK_FULL(btstack)\
128 	( (btstack)->top == &((btstack)->stack[MAXTREEHEIGHT-1]))
129 
130 #define BT_PUSH(BTSTACK, BN, INDEX)\
131 {\
132 	assert(!BT_STACK_FULL(BTSTACK));\
133 	(BTSTACK)->top->bn = BN;\
134 	(BTSTACK)->top->index = INDEX;\
135 	++(BTSTACK)->top;\
136 }
137 
138 #define BT_POP(btstack)\
139 	( (btstack)->top == (btstack)->stack ? NULL : --(btstack)->top )
140 
141 #define BT_STACK(btstack)\
142 	( (btstack)->top == (btstack)->stack ? NULL : (btstack)->top )
143 
BT_STACK_DUMP(struct btstack * btstack)144 static inline void BT_STACK_DUMP(struct btstack *btstack)
145 {
146 	int i;
147 	printk("btstack dump:\n");
148 	for (i = 0; i < MAXTREEHEIGHT; i++)
149 		printk(KERN_ERR "bn = %Lx, index = %d\n",
150 		       (long long)btstack->stack[i].bn,
151 		       btstack->stack[i].index);
152 }
153 
154 /* retrieve search results */
155 #define BT_GETSEARCH(IP, LEAF, BN, MP, TYPE, P, INDEX, ROOT)\
156 {\
157 	BN = (LEAF)->bn;\
158 	MP = (LEAF)->mp;\
159 	if (BN)\
160 		P = (TYPE *)MP->data;\
161 	else\
162 		P = (TYPE *)&JFS_IP(IP)->ROOT;\
163 	INDEX = (LEAF)->index;\
164 }
165 
166 /* put the page buffer of search */
167 #define BT_PUTSEARCH(BTSTACK)\
168 {\
169 	if (! BT_IS_ROOT((BTSTACK)->top->mp))\
170 		release_metapage((BTSTACK)->top->mp);\
171 }
172 #endif				/* _H_JFS_BTREE */
173