Reword slightly and point out that DESTDIR has to exist.
[dragonfly.git] / sys / vfs / hammer / hammer_cursor.h
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1/*
2 * Copyright (c) 2007 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
4e17f465 34 * $DragonFly: src/sys/vfs/hammer/hammer_cursor.h,v 1.17 2008/05/03 05:28:55 dillon Exp $
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35 */
36
37/*
38 * The hammer_cursor structure is the primary in-memory management structure
39 * for B-Tree operations.
40 *
41 * The most important issue to make note of is that a hammer_cursor is a
42 * tracking structure. Any active hammer_cursor structure will be linked into
43 * hammer_node based lists and B-Tree operations executed by unrelated
44 * treads MAY MODIFY YOUR CURSOR when you are not holding an exclusive
45 * lock on the cursor's nodes.
46 *
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47 * The cursor module maintains a shared lock on cursor->node and
48 * cursor->parent.
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49 */
50struct hammer_cursor {
51 /*
52 * Parent B-Tree node, current B-Tree node, and related element
53 * indices.
54 */
36f82b23 55 hammer_transaction_t trans;
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56 hammer_node_t parent;
57 int parent_index;
6a37e7e4 58
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59 hammer_node_t node;
60 int index;
8cd0a023 61
6a37e7e4 62 /*
4e17f465 63 * Set if a deadlock occurs. hammer_done_cursor() will block on
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64 * this after releasing parent and node, before returning.
65 */
66 hammer_node_t deadlk_node;
b84de5af 67 hammer_record_t deadlk_rec;
6a37e7e4 68
b33e2cc0 69 /*
9582c7da 70 * Set along with HAMMER_CURSOR_CREATE_CHECK when doing an as-of
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71 * search. If ENOENT is returned and the flag is set, the caller
72 * must iterate with a new delete_tid.
73 */
9582c7da 74 hammer_tid_t create_check;
b33e2cc0 75
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76 /*
77 * Pointer to the current node's bounds. Typically points to the
78 * appropriate boundary elements in the parent or points to bounds
79 * stored in the cluster. The right-boundary is range-exclusive.
80 */
81 hammer_base_elm_t left_bound;
82 hammer_base_elm_t right_bound;
83
84 /*
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85 * Key or key range governing search. The cursor code may adjust
86 * key_beg/key_end if asof is non-zero.
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87 */
88 struct hammer_base_elm key_beg;
89 struct hammer_base_elm key_end;
d5530d22 90 hammer_tid_t asof;
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91
92 /*
93 * Related data and record references. Note that the related buffers
94 * can be NULL when data and/or record is not, typically indicating
95 * information referenced via an in-memory record.
96 */
40043e7f 97 struct hammer_buffer *record_buffer; /* record (+ built-in data) */
47197d71 98 struct hammer_buffer *data_buffer; /* extended data */
8cd0a023 99 union hammer_record_ondisk *record;
40043e7f 100 union hammer_data_ondisk *data;
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101
102 /*
103 * Iteration and extraction control variables
104 */
105 int flags;
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106
107 /*
108 * Merged in-memory/on-disk iterations also use these fields.
109 */
110 struct hammer_inode *ip;
111 struct hammer_record *iprec;
112};
113
114typedef struct hammer_cursor *hammer_cursor_t;
115
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116#define HAMMER_CURSOR_GET_RECORD 0x0001
117#define HAMMER_CURSOR_GET_DATA 0x0002
b84de5af 118#define HAMMER_CURSOR_BACKEND 0x0004 /* cursor run by backend */
a89aec1b 119#define HAMMER_CURSOR_INSERT 0x0008 /* adjust for insert */
b84de5af 120#define HAMMER_CURSOR_DELETE_VISIBILITY 0x0010 /* special del-on-disk recs */
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121#define HAMMER_CURSOR_END_INCLUSIVE 0x0020 /* key_end is inclusive */
122#define HAMMER_CURSOR_END_EXCLUSIVE 0x0040 /* key_end is exclusive (def) */
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123
124#define HAMMER_CURSOR_ATEDISK 0x0100
125#define HAMMER_CURSOR_ATEMEM 0x0200
126#define HAMMER_CURSOR_DISKEOF 0x0400
127#define HAMMER_CURSOR_MEMEOF 0x0800
195c19a1 128#define HAMMER_CURSOR_DELBTREE 0x1000 /* ip_delete from b-tree */
47197d71 129#define HAMMER_CURSOR_DATAEXTOK 0x2000 /* allow data extension */
d5530d22 130#define HAMMER_CURSOR_ASOF 0x4000 /* as-of lookup */
9582c7da 131#define HAMMER_CURSOR_CREATE_CHECK 0x8000 /* as-of lookup */
8cd0a023 132
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133/*
134 * Flags we can clear when reusing a cursor (we can clear all of them)
135 */
136#define HAMMER_CURSOR_INITMASK (~0)
137