Nuke staled code
[dragonfly.git] / sys / vfs / hammer / hammer_cursor.h
CommitLineData
8cd0a023
MD
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 *
fe7678ee 34 * $DragonFly: src/sys/vfs/hammer/hammer_cursor.h,v 1.7 2008/01/17 05:06:09 dillon Exp $
8cd0a023
MD
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 *
47 * Most operations maintain an exclusive lock on their node and
48 * parent node, but certain cursor operations may temporarily release
49 * one or both locks. In particular, a cursor_up operation may have
50 * to temporarily release underlying locks to avoid a deadlock.
51 */
52struct hammer_cursor {
53 /*
54 * Parent B-Tree node, current B-Tree node, and related element
55 * indices.
56 */
57 hammer_node_t parent;
58 int parent_index;
59 hammer_node_t node;
60 int index;
61
62 /*
63 * Pointer to the current node's bounds. Typically points to the
64 * appropriate boundary elements in the parent or points to bounds
65 * stored in the cluster. The right-boundary is range-exclusive.
66 */
67 hammer_base_elm_t left_bound;
68 hammer_base_elm_t right_bound;
69
70 /*
d5530d22
MD
71 * Key or key range governing search. The cursor code may adjust
72 * key_beg/key_end if asof is non-zero.
8cd0a023
MD
73 */
74 struct hammer_base_elm key_beg;
75 struct hammer_base_elm key_end;
d5530d22 76 hammer_tid_t asof;
8cd0a023
MD
77
78 /*
79 * Related data and record references. Note that the related buffers
80 * can be NULL when data and/or record is not, typically indicating
81 * information referenced via an in-memory record.
82 */
83 struct hammer_buffer *data_buffer; /* extracted data & record */
84 union hammer_data_ondisk *data;
85 struct hammer_buffer *record_buffer;
86 union hammer_record_ondisk *record;
87
88 /*
89 * Iteration and extraction control variables
90 */
91 int flags;
8cd0a023
MD
92
93 /*
94 * Merged in-memory/on-disk iterations also use these fields.
95 */
96 struct hammer_inode *ip;
97 struct hammer_record *iprec;
6b4f890b 98 struct hammer_rec_rb_tree_scan_info scan;
8cd0a023
MD
99};
100
101typedef struct hammer_cursor *hammer_cursor_t;
102
a89aec1b
MD
103#define HAMMER_CURSOR_GET_RECORD 0x0001
104#define HAMMER_CURSOR_GET_DATA 0x0002
d26d0ae9 105#define HAMMER_CURSOR_INCLUSTER 0x0004 /* stay in the cluster */
a89aec1b
MD
106#define HAMMER_CURSOR_INSERT 0x0008 /* adjust for insert */
107#define HAMMER_CURSOR_DELETE 0x0010 /* adjust for delete */
d26d0ae9
MD
108#define HAMMER_CURSOR_END_INCLUSIVE 0x0020 /* key_end is inclusive */
109#define HAMMER_CURSOR_END_EXCLUSIVE 0x0040 /* key_end is exclusive (def) */
a89aec1b
MD
110
111#define HAMMER_CURSOR_ATEDISK 0x0100
112#define HAMMER_CURSOR_ATEMEM 0x0200
113#define HAMMER_CURSOR_DISKEOF 0x0400
114#define HAMMER_CURSOR_MEMEOF 0x0800
195c19a1 115#define HAMMER_CURSOR_DELBTREE 0x1000 /* ip_delete from b-tree */
d26d0ae9 116#define HAMMER_CURSOR_DATA_EMBEDDED 0x2000 /* embedded flag on extract */
d5530d22 117#define HAMMER_CURSOR_ASOF 0x4000 /* as-of lookup */
8cd0a023 118