/* * Copyright (c) 2007 The DragonFly Project. All rights reserved. * * This code is derived from software contributed to The DragonFly Project * by Matthew Dillon <dillon@backplane.com> * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name of The DragonFly Project nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific, prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $DragonFly: src/sys/vfs/hammer/hammer_cursor.h,v 1.26 2008/08/06 15:38:58 dillon Exp $ */ #ifndef VFS_HAMMER_CURSOR_H_ #define VFS_HAMMER_CURSOR_H_ /* * The hammer_cursor structure is the primary in-memory management structure * for B-Tree operations. * * The most important issue to make note of is that a hammer_cursor is a * tracking structure. Any active hammer_cursor structure will be linked into * hammer_node based lists and B-Tree operations executed by unrelated * treads MAY MODIFY YOUR CURSOR when you are not holding an exclusive * lock on the cursor's nodes. * * The cursor module maintains a shared lock on cursor->node and * cursor->parent. */ typedef struct hammer_cursor { /* * Parent B-Tree node, current B-Tree node, and related element * indices. */ hammer_transaction_t trans; hammer_node_t parent; int parent_index; hammer_node_t node; int index; /* * Set if a deadlock occurs. hammer_done_cursor() will block on * this after releasing parent and node, before returning. See * also hammer_recover_cursor(). */ TAILQ_ENTRY(hammer_cursor) deadlk_entry; hammer_node_t deadlk_node; hammer_record_t deadlk_rec; /* * Set along with HAMMER_CURSOR_CREATE_CHECK when doing an as-of * search. If ENOENT is returned and the flag is set, the caller * must iterate with a new delete_tid. */ hammer_tid_t create_check; /* * Pointer to the current node's bounds. Typically points to the * appropriate boundary elements in the parent. * The right-boundary is range-exclusive. */ hammer_base_elm_t left_bound; hammer_base_elm_t right_bound; /* * Key or key range governing search. The cursor code may adjust * key_beg/key_end if asof is non-zero. */ struct hammer_base_elm key_beg; struct hammer_base_elm key_end; hammer_tid_t asof; struct hammer_cmirror *cmirror; /* * Related data and record references. Note that the related buffers * can be NULL when data and/or record is not, typically indicating * information referenced via an in-memory record. */ hammer_buffer_t data_buffer; /* extended data */ hammer_btree_leaf_elm_t leaf; hammer_data_ondisk_t data; /* * Iteration and extraction control variables */ int flags; int rec_generation; /* * Merged in-memory/on-disk iterations also use these fields. */ hammer_inode_t ip; hammer_record_t iprec; } *hammer_cursor_t; #define HAMMER_CURSOR_GET_LEAF 0x0001 /* not used */ #define HAMMER_CURSOR_GET_DATA 0x0002 #define HAMMER_CURSOR_BACKEND 0x0004 /* cursor run by backend */ #define HAMMER_CURSOR_INSERT 0x0008 /* adjust for insert */ #define HAMMER_CURSOR_DELETE_VISIBILITY 0x0010 /* special del-on-disk recs */ #define HAMMER_CURSOR_END_INCLUSIVE 0x0020 /* key_end is inclusive */ #define HAMMER_CURSOR_END_EXCLUSIVE 0x0040 /* key_end is exclusive (def) */ #define HAMMER_CURSOR_ATEDISK 0x0100 #define HAMMER_CURSOR_ATEMEM 0x0200 #define HAMMER_CURSOR_DISKEOF 0x0400 #define HAMMER_CURSOR_MEMEOF 0x0800 #define HAMMER_CURSOR_RETEST 0x1000 /* retest current element */ #define HAMMER_CURSOR_MIRROR_FILTERED 0x2000 /* mirror_tid filter */ #define HAMMER_CURSOR_ASOF 0x4000 /* as-of lookup */ #define HAMMER_CURSOR_CREATE_CHECK 0x8000 /* as-of lookup */ #define HAMMER_CURSOR_PRUNING 0x00010000 #define HAMMER_CURSOR_REBLOCKING 0x00020000 #define HAMMER_CURSOR_TRACKED 0x00040000 #define HAMMER_CURSOR_TRACKED_RIPOUT 0x00080000 #define HAMMER_CURSOR_LASTWASMEM 0x00100000 /* hammer_ip_next logic */ #define HAMMER_CURSOR_ITERATE_CHECK 0x00200000 #define HAMMER_CURSOR_NOSWAPCACHE 0x00400000 /* applies to LARGE_DATA */ /* * Flags we can clear when reusing a cursor (we can clear all of them) */ #define HAMMER_CURSOR_INITMASK (~0) /* * Mirror scan extension structure. Caller sets mirror_tid to restrict * the scan. If the iteration is able to skip one or more internal nodes * it returns an internal node with skip_beg/end set to the skipped range. * * If the first element of an internal node is skipped skip_beg will use * the left_bound inherited from the parent, and the same for the last * element. This is because gaps can develop in the bounds. */ struct hammer_cmirror { hammer_tid_t mirror_tid; struct hammer_base_elm skip_beg; struct hammer_base_elm skip_end; }; /* * NOTE: iprec can be NULL, but the address-of does not indirect through * it so we are ok. */ #define hammer_cursor_inmem(cursor) \ ((cursor)->leaf == &(cursor)->iprec->leaf) #define hammer_cursor_ondisk(cursor) \ ((cursor)->leaf != &(cursor)->iprec->leaf) #endif /* !VFS_HAMMER_CURSOR_H_ */
