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 * 34 * $DragonFly: src/sys/vfs/hammer/hammer_cursor.h,v 1.26 2008/08/06 15:38:58 dillon Exp $ 35 */ 36 37 struct hammer_cmirror; 38 39 /* 40 * The hammer_cursor structure is the primary in-memory management structure 41 * for B-Tree operations. 42 * 43 * The most important issue to make note of is that a hammer_cursor is a 44 * tracking structure. Any active hammer_cursor structure will be linked into 45 * hammer_node based lists and B-Tree operations executed by unrelated 46 * treads MAY MODIFY YOUR CURSOR when you are not holding an exclusive 47 * lock on the cursor's nodes. 48 * 49 * The cursor module maintains a shared lock on cursor->node and 50 * cursor->parent. 51 */ 52 struct hammer_cursor { 53 /* 54 * Parent B-Tree node, current B-Tree node, and related element 55 * indices. 56 */ 57 hammer_transaction_t trans; 58 hammer_node_t parent; 59 int parent_index; 60 61 hammer_node_t node; 62 int index; 63 64 /* 65 * Set if a deadlock occurs. hammer_done_cursor() will block on 66 * this after releasing parent and node, before returning. See 67 * also hammer_recover_cursor(). 68 */ 69 TAILQ_ENTRY(hammer_cursor) deadlk_entry; 70 hammer_node_t deadlk_node; 71 hammer_record_t deadlk_rec; 72 73 /* 74 * Set along with HAMMER_CURSOR_CREATE_CHECK when doing an as-of 75 * search. If ENOENT is returned and the flag is set, the caller 76 * must iterate with a new delete_tid. 77 */ 78 hammer_tid_t create_check; 79 80 /* 81 * Pointer to the current node's bounds. Typically points to the 82 * appropriate boundary elements in the parent or points to bounds 83 * stored in the cluster. The right-boundary is range-exclusive. 84 */ 85 hammer_base_elm_t left_bound; 86 hammer_base_elm_t right_bound; 87 88 /* 89 * Key or key range governing search. The cursor code may adjust 90 * key_beg/key_end if asof is non-zero. 91 */ 92 struct hammer_base_elm key_beg; 93 struct hammer_base_elm key_end; 94 hammer_tid_t asof; 95 struct hammer_cmirror *cmirror; 96 97 /* 98 * Related data and record references. Note that the related buffers 99 * can be NULL when data and/or record is not, typically indicating 100 * information referenced via an in-memory record. 101 */ 102 struct hammer_buffer *data_buffer; /* extended data */ 103 struct hammer_btree_leaf_elm *leaf; 104 union hammer_data_ondisk *data; 105 106 /* 107 * Iteration and extraction control variables 108 */ 109 int flags; 110 int rec_generation; 111 112 /* 113 * Merged in-memory/on-disk iterations also use these fields. 114 */ 115 struct hammer_inode *ip; 116 struct hammer_record *iprec; 117 }; 118 119 typedef struct hammer_cursor *hammer_cursor_t; 120 121 #define HAMMER_CURSOR_GET_LEAF 0x0001 122 #define HAMMER_CURSOR_GET_DATA 0x0002 123 #define HAMMER_CURSOR_BACKEND 0x0004 /* cursor run by backend */ 124 #define HAMMER_CURSOR_INSERT 0x0008 /* adjust for insert */ 125 #define HAMMER_CURSOR_DELETE_VISIBILITY 0x0010 /* special del-on-disk recs */ 126 #define HAMMER_CURSOR_END_INCLUSIVE 0x0020 /* key_end is inclusive */ 127 #define HAMMER_CURSOR_END_EXCLUSIVE 0x0040 /* key_end is exclusive (def) */ 128 129 #define HAMMER_CURSOR_ATEDISK 0x0100 130 #define HAMMER_CURSOR_ATEMEM 0x0200 131 #define HAMMER_CURSOR_DISKEOF 0x0400 132 #define HAMMER_CURSOR_MEMEOF 0x0800 133 #define HAMMER_CURSOR_RETEST 0x1000 /* retest current element */ 134 #define HAMMER_CURSOR_MIRROR_FILTERED 0x2000 /* mirror_tid filter */ 135 #define HAMMER_CURSOR_ASOF 0x4000 /* as-of lookup */ 136 #define HAMMER_CURSOR_CREATE_CHECK 0x8000 /* as-of lookup */ 137 138 #define HAMMER_CURSOR_PRUNING 0x00010000 139 #define HAMMER_CURSOR_REBLOCKING 0x00020000 140 #define HAMMER_CURSOR_TRACKED 0x00040000 141 #define HAMMER_CURSOR_TRACKED_RIPOUT 0x00080000 142 #define HAMMER_CURSOR_LASTWASMEM 0x00100000 /* hammer_ip_next logic */ 143 #define HAMMER_CURSOR_ITERATE_CHECK 0x00200000 144 #define HAMMER_CURSOR_NOSWAPCACHE 0x00400000 /* applies to LARGE_DATA */ 145 146 /* 147 * Flags we can clear when reusing a cursor (we can clear all of them) 148 */ 149 #define HAMMER_CURSOR_INITMASK (~0) 150 151 /* 152 * Mirror scan extension structure. Caller sets mirror_tid to restrict 153 * the scan. If the iteration is able to skip one or more internal nodes 154 * it returns an internal node with skip_beg/end set to the skipped range. 155 * 156 * If the first element of an internal node is skipped skip_beg will use 157 * the left_bound inherited from the parent, and the same for the last 158 * element. This is because gaps can develop in the bounds. 159 */ 160 struct hammer_cmirror { 161 hammer_tid_t mirror_tid; 162 struct hammer_base_elm skip_beg; 163 struct hammer_base_elm skip_end; 164 }; 165 166 /* 167 * NOTE: iprec can be NULL, but the address-of does not indirect through 168 * it so we are ok. 169 */ 170 #define hammer_cursor_inmem(cursor) \ 171 ((cursor)->leaf == &(cursor)->iprec->leaf) 172 #define hammer_cursor_ondisk(cursor) \ 173 ((cursor)->leaf != &(cursor)->iprec->leaf) 174 175