2 * Copyright (c) 2007-2008 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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
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.
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
34 * $DragonFly: src/sys/vfs/hammer/hammer_cursor.c,v 1.42 2008/08/06 15:38:58 dillon Exp $
38 * HAMMER B-Tree index - cursor support routines
42 static int hammer_load_cursor_parent(hammer_cursor_t cursor
, int try_exclusive
);
45 * Initialize a fresh cursor using the B-Tree node cache. If the cache
46 * is not available initialize a fresh cursor at the root of the filesystem.
49 hammer_init_cursor(hammer_transaction_t trans
, hammer_cursor_t cursor
,
50 hammer_node_cache_t cache
, hammer_inode_t ip
)
52 hammer_volume_t volume
;
56 bzero(cursor
, sizeof(*cursor
));
58 cursor
->trans
= trans
;
61 * If the cursor operation is on behalf of an inode, lock
64 if ((cursor
->ip
= ip
) != NULL
) {
66 if (trans
->type
== HAMMER_TRANS_FLS
)
67 hammer_lock_ex(&ip
->lock
);
69 hammer_lock_sh(&ip
->lock
);
73 * Step 1 - acquire a locked node from the cache if possible
75 if (cache
&& cache
->node
) {
76 node
= hammer_ref_node_safe(trans
, cache
, &error
);
78 hammer_lock_sh(&node
->lock
);
79 if (node
->flags
& HAMMER_NODE_DELETED
) {
80 hammer_unlock(&node
->lock
);
81 hammer_rel_node(node
);
86 ++hammer_stats_btree_root_iterations
;
89 ++hammer_stats_btree_root_iterations
;
93 * Step 2 - If we couldn't get a node from the cache, get
94 * the one from the root of the filesystem.
96 while (node
== NULL
) {
97 volume
= hammer_get_root_volume(trans
->hmp
, &error
);
100 node
= hammer_get_node(trans
, volume
->ondisk
->vol0_btree_root
,
102 hammer_rel_volume(volume
, 0);
105 hammer_lock_sh(&node
->lock
);
108 * If someone got in before we could lock the node, retry.
110 if (node
->flags
& HAMMER_NODE_DELETED
) {
111 hammer_unlock(&node
->lock
);
112 hammer_rel_node(node
);
116 if (volume
->ondisk
->vol0_btree_root
!= node
->node_offset
) {
117 hammer_unlock(&node
->lock
);
118 hammer_rel_node(node
);
125 * Step 3 - finish initializing the cursor by acquiring the parent
129 error
= hammer_load_cursor_parent(cursor
, 0);
130 KKASSERT(error
== 0);
131 /* if (error) hammer_done_cursor(cursor); */
136 * Normalize a cursor. Sometimes cursors can be left in a state
137 * where node is NULL. If the cursor is in this state, cursor up.
140 hammer_normalize_cursor(hammer_cursor_t cursor
)
142 if (cursor
->node
== NULL
) {
143 KKASSERT(cursor
->parent
!= NULL
);
144 hammer_cursor_up(cursor
);
150 * We are finished with a cursor. We NULL out various fields as sanity
151 * check, in case the structure is inappropriately used afterwords.
154 hammer_done_cursor(hammer_cursor_t cursor
)
158 KKASSERT((cursor
->flags
& HAMMER_CURSOR_TRACKED
) == 0);
159 if (cursor
->parent
) {
160 hammer_unlock(&cursor
->parent
->lock
);
161 hammer_rel_node(cursor
->parent
);
162 cursor
->parent
= NULL
;
165 hammer_unlock(&cursor
->node
->lock
);
166 hammer_rel_node(cursor
->node
);
169 if (cursor
->data_buffer
) {
170 hammer_rel_buffer(cursor
->data_buffer
, 0);
171 cursor
->data_buffer
= NULL
;
173 if ((ip
= cursor
->ip
) != NULL
) {
174 KKASSERT(ip
->cursor_ip_refs
> 0);
175 --ip
->cursor_ip_refs
;
176 hammer_unlock(&ip
->lock
);
180 hammer_rel_mem_record(cursor
->iprec
);
181 cursor
->iprec
= NULL
;
185 * If we deadlocked this node will be referenced. Do a quick
186 * lock/unlock to wait for the deadlock condition to clear.
188 if (cursor
->deadlk_node
) {
189 hammer_lock_ex_ident(&cursor
->deadlk_node
->lock
, "hmrdlk");
190 hammer_unlock(&cursor
->deadlk_node
->lock
);
191 hammer_rel_node(cursor
->deadlk_node
);
192 cursor
->deadlk_node
= NULL
;
194 if (cursor
->deadlk_rec
) {
195 hammer_wait_mem_record_ident(cursor
->deadlk_rec
, "hmmdlr");
196 hammer_rel_mem_record(cursor
->deadlk_rec
);
197 cursor
->deadlk_rec
= NULL
;
202 cursor
->left_bound
= NULL
;
203 cursor
->right_bound
= NULL
;
204 cursor
->trans
= NULL
;
208 * Upgrade cursor->node and cursor->parent to exclusive locks. This
209 * function can return EDEADLK.
211 * The lock must already be either held shared or already held exclusively
214 * If we fail to upgrade the lock and cursor->deadlk_node is NULL,
215 * we add another reference to the node that failed and set
216 * cursor->deadlk_node so hammer_done_cursor() can block on it.
219 hammer_cursor_upgrade(hammer_cursor_t cursor
)
223 error
= hammer_lock_upgrade(&cursor
->node
->lock
);
224 if (error
&& cursor
->deadlk_node
== NULL
) {
225 cursor
->deadlk_node
= cursor
->node
;
226 hammer_ref_node(cursor
->deadlk_node
);
227 } else if (error
== 0 && cursor
->parent
) {
228 error
= hammer_lock_upgrade(&cursor
->parent
->lock
);
229 if (error
&& cursor
->deadlk_node
== NULL
) {
230 cursor
->deadlk_node
= cursor
->parent
;
231 hammer_ref_node(cursor
->deadlk_node
);
238 hammer_cursor_upgrade_node(hammer_cursor_t cursor
)
242 error
= hammer_lock_upgrade(&cursor
->node
->lock
);
243 if (error
&& cursor
->deadlk_node
== NULL
) {
244 cursor
->deadlk_node
= cursor
->node
;
245 hammer_ref_node(cursor
->deadlk_node
);
251 * Downgrade cursor->node and cursor->parent to shared locks. This
252 * function can return EDEADLK.
255 hammer_cursor_downgrade(hammer_cursor_t cursor
)
257 if (hammer_lock_excl_owned(&cursor
->node
->lock
, curthread
))
258 hammer_lock_downgrade(&cursor
->node
->lock
);
259 if (cursor
->parent
&&
260 hammer_lock_excl_owned(&cursor
->parent
->lock
, curthread
)) {
261 hammer_lock_downgrade(&cursor
->parent
->lock
);
266 * Seek the cursor to the specified node and index.
268 * The caller must ref the node prior to calling this routine and release
269 * it after it returns. If the seek succeeds the cursor will gain its own
273 hammer_cursor_seek(hammer_cursor_t cursor
, hammer_node_t node
, int index
)
277 hammer_cursor_downgrade(cursor
);
280 if (cursor
->node
!= node
) {
281 hammer_unlock(&cursor
->node
->lock
);
282 hammer_rel_node(cursor
->node
);
284 hammer_ref_node(node
);
285 hammer_lock_sh(&node
->lock
);
286 KKASSERT ((node
->flags
& HAMMER_NODE_DELETED
) == 0);
288 if (cursor
->parent
) {
289 hammer_unlock(&cursor
->parent
->lock
);
290 hammer_rel_node(cursor
->parent
);
291 cursor
->parent
= NULL
;
292 cursor
->parent_index
= 0;
294 error
= hammer_load_cursor_parent(cursor
, 0);
296 cursor
->index
= index
;
301 * Load the parent of cursor->node into cursor->parent.
305 hammer_load_cursor_parent(hammer_cursor_t cursor
, int try_exclusive
)
308 hammer_node_t parent
;
310 hammer_btree_elm_t elm
;
314 hmp
= cursor
->trans
->hmp
;
316 if (cursor
->node
->ondisk
->parent
) {
318 parent
= hammer_btree_get_parent(cursor
->trans
, node
,
320 &error
, try_exclusive
);
322 elm
= &parent
->ondisk
->elms
[parent_index
];
323 cursor
->parent
= parent
;
324 cursor
->parent_index
= parent_index
;
325 cursor
->left_bound
= &elm
[0].internal
.base
;
326 cursor
->right_bound
= &elm
[1].internal
.base
;
329 cursor
->parent
= NULL
;
330 cursor
->parent_index
= 0;
331 cursor
->left_bound
= &hmp
->root_btree_beg
;
332 cursor
->right_bound
= &hmp
->root_btree_end
;
339 * Cursor up to our parent node. Return ENOENT if we are at the root of
343 hammer_cursor_up(hammer_cursor_t cursor
)
347 hammer_cursor_downgrade(cursor
);
350 * If the parent is NULL we are at the root of the B-Tree and
353 if (cursor
->parent
== NULL
)
357 * Set the node to its parent.
359 hammer_unlock(&cursor
->node
->lock
);
360 hammer_rel_node(cursor
->node
);
361 cursor
->node
= cursor
->parent
;
362 cursor
->index
= cursor
->parent_index
;
363 cursor
->parent
= NULL
;
364 cursor
->parent_index
= 0;
366 error
= hammer_load_cursor_parent(cursor
, 0);
371 * Special cursor up given a locked cursor. The orignal node is not
372 * unlocked or released and the cursor is not downgraded.
374 * This function can fail with EDEADLK.
376 * This function is only run when recursively deleting parent nodes
377 * to get rid of an empty leaf.
380 hammer_cursor_up_locked(hammer_cursor_t cursor
)
387 * If the parent is NULL we are at the root of the B-Tree and
390 if (cursor
->parent
== NULL
)
394 save_index
= cursor
->index
;
397 * Set the node to its parent.
399 cursor
->node
= cursor
->parent
;
400 cursor
->index
= cursor
->parent_index
;
401 cursor
->parent
= NULL
;
402 cursor
->parent_index
= 0;
405 * load the new parent, attempt to exclusively lock it. Note that
406 * we are still holding the old parent (now cursor->node) exclusively
409 * This can return EDEADLK. Undo the operation on any error. These
410 * up sequences can occur during iterations so be sure to restore
413 error
= hammer_load_cursor_parent(cursor
, 1);
415 cursor
->parent
= cursor
->node
;
416 cursor
->parent_index
= cursor
->index
;
418 cursor
->index
= save_index
;
425 * Cursor down through the current node, which must be an internal node.
427 * This routine adjusts the cursor and sets index to 0.
430 hammer_cursor_down(hammer_cursor_t cursor
)
433 hammer_btree_elm_t elm
;
437 * The current node becomes the current parent
439 hammer_cursor_downgrade(cursor
);
441 KKASSERT(cursor
->index
>= 0 && cursor
->index
< node
->ondisk
->count
);
442 if (cursor
->parent
) {
443 hammer_unlock(&cursor
->parent
->lock
);
444 hammer_rel_node(cursor
->parent
);
446 cursor
->parent
= node
;
447 cursor
->parent_index
= cursor
->index
;
452 * Extract element to push into at (node,index), set bounds.
454 elm
= &node
->ondisk
->elms
[cursor
->parent_index
];
457 * Ok, push down into elm. If elm specifies an internal or leaf
458 * node the current node must be an internal node. If elm specifies
459 * a spike then the current node must be a leaf node.
461 switch(elm
->base
.btype
) {
462 case HAMMER_BTREE_TYPE_INTERNAL
:
463 case HAMMER_BTREE_TYPE_LEAF
:
464 KKASSERT(node
->ondisk
->type
== HAMMER_BTREE_TYPE_INTERNAL
);
465 KKASSERT(elm
->internal
.subtree_offset
!= 0);
466 cursor
->left_bound
= &elm
[0].internal
.base
;
467 cursor
->right_bound
= &elm
[1].internal
.base
;
468 node
= hammer_get_node(cursor
->trans
,
469 elm
->internal
.subtree_offset
, 0, &error
);
471 KASSERT(elm
->base
.btype
== node
->ondisk
->type
, ("BTYPE MISMATCH %c %c NODE %p\n", elm
->base
.btype
, node
->ondisk
->type
, node
));
472 if (node
->ondisk
->parent
!= cursor
->parent
->node_offset
)
473 panic("node %p %016llx vs %016llx\n", node
, (long long)node
->ondisk
->parent
, (long long)cursor
->parent
->node_offset
);
474 KKASSERT(node
->ondisk
->parent
== cursor
->parent
->node_offset
);
478 panic("hammer_cursor_down: illegal btype %02x (%c)\n",
480 (elm
->base
.btype
? elm
->base
.btype
: '?'));
484 hammer_lock_sh(&node
->lock
);
485 KKASSERT ((node
->flags
& HAMMER_NODE_DELETED
) == 0);
492 /************************************************************************
493 * DEADLOCK RECOVERY *
494 ************************************************************************
496 * These are the new deadlock recovery functions. Currently they are only
497 * used for the mirror propagation and physical node removal cases but
498 * ultimately the intention is to use them for all deadlock recovery
501 * WARNING! The contents of the cursor may be modified while unlocked.
502 * passive modifications including adjusting the node, parent,
503 * indexes, and leaf pointer.
505 * An outright removal of the element the cursor was pointing at
506 * will cause the HAMMER_CURSOR_TRACKED_RIPOUT flag to be set,
507 * which chains to causing the HAMMER_CURSOR_RETEST to be set
508 * when the cursor is locked again.
511 hammer_unlock_cursor(hammer_cursor_t cursor
)
515 KKASSERT((cursor
->flags
& HAMMER_CURSOR_TRACKED
) == 0);
516 KKASSERT(cursor
->node
);
519 * Release the cursor's locks and track B-Tree operations on node.
520 * While being tracked our cursor can be modified by other threads
521 * and the node may be replaced.
523 if (cursor
->parent
) {
524 hammer_unlock(&cursor
->parent
->lock
);
525 hammer_rel_node(cursor
->parent
);
526 cursor
->parent
= NULL
;
529 cursor
->flags
|= HAMMER_CURSOR_TRACKED
;
530 TAILQ_INSERT_TAIL(&node
->cursor_list
, cursor
, deadlk_entry
);
531 hammer_unlock(&node
->lock
);
535 * Get the cursor heated up again. The cursor's node may have
536 * changed and we might have to locate the new parent.
538 * If the exact element we were on got deleted RIPOUT will be
539 * set and we must clear ATEDISK so an iteration does not skip
540 * the element after it.
543 hammer_lock_cursor(hammer_cursor_t cursor
)
548 KKASSERT(cursor
->flags
& HAMMER_CURSOR_TRACKED
);
555 hammer_ref_node(node
);
556 hammer_lock_sh(&node
->lock
);
557 if (cursor
->node
== node
) {
558 hammer_rel_node(node
);
561 hammer_unlock(&node
->lock
);
562 hammer_rel_node(node
);
566 * Untrack the cursor, clean up, and re-establish the parent node.
568 TAILQ_REMOVE(&node
->cursor_list
, cursor
, deadlk_entry
);
569 cursor
->flags
&= ~HAMMER_CURSOR_TRACKED
;
572 * If a ripout has occured iterations must re-test the (new)
573 * current element. Clearing ATEDISK prevents the element from
574 * being skipped and RETEST causes it to be re-tested.
576 if (cursor
->flags
& HAMMER_CURSOR_TRACKED_RIPOUT
) {
577 cursor
->flags
&= ~HAMMER_CURSOR_TRACKED_RIPOUT
;
578 cursor
->flags
&= ~HAMMER_CURSOR_ATEDISK
;
579 cursor
->flags
|= HAMMER_CURSOR_RETEST
;
581 error
= hammer_load_cursor_parent(cursor
, 0);
586 * Recover from a deadlocked cursor, tracking any node removals or
587 * replacements. If the cursor's current node is removed by another
588 * thread (via btree_remove()) the cursor will be seeked upwards.
590 * The caller is working a modifying operation and must be holding the
591 * sync lock (shared). We do not release the sync lock because this
592 * would break atomicy.
595 hammer_recover_cursor(hammer_cursor_t cursor
)
599 hammer_unlock_cursor(cursor
);
600 KKASSERT(cursor
->trans
->sync_lock_refs
> 0);
603 * Wait for the deadlock to clear
605 if (cursor
->deadlk_node
) {
606 hammer_lock_ex_ident(&cursor
->deadlk_node
->lock
, "hmrdlk");
607 hammer_unlock(&cursor
->deadlk_node
->lock
);
608 hammer_rel_node(cursor
->deadlk_node
);
609 cursor
->deadlk_node
= NULL
;
611 if (cursor
->deadlk_rec
) {
612 hammer_wait_mem_record_ident(cursor
->deadlk_rec
, "hmmdlr");
613 hammer_rel_mem_record(cursor
->deadlk_rec
);
614 cursor
->deadlk_rec
= NULL
;
616 error
= hammer_lock_cursor(cursor
);
621 * Dup ocursor to ncursor. ncursor inherits ocursor's locks and ocursor
622 * is effectively unlocked and becomes tracked. If ocursor was not locked
623 * then ncursor also inherits the tracking.
625 * After the caller finishes working with ncursor it must be cleaned up
626 * with hammer_done_cursor(), and the caller must re-lock ocursor.
629 hammer_push_cursor(hammer_cursor_t ocursor
)
631 hammer_cursor_t ncursor
;
636 hmp
= ocursor
->trans
->hmp
;
637 ncursor
= kmalloc(sizeof(*ncursor
), hmp
->m_misc
, M_WAITOK
| M_ZERO
);
638 bcopy(ocursor
, ncursor
, sizeof(*ocursor
));
640 node
= ocursor
->node
;
641 hammer_ref_node(node
);
642 if ((ocursor
->flags
& HAMMER_CURSOR_TRACKED
) == 0) {
643 ocursor
->flags
|= HAMMER_CURSOR_TRACKED
;
644 TAILQ_INSERT_TAIL(&node
->cursor_list
, ocursor
, deadlk_entry
);
647 ocursor
->parent
= NULL
;
648 ocursor
->data_buffer
= NULL
;
649 ocursor
->leaf
= NULL
;
650 ocursor
->data
= NULL
;
651 if (ncursor
->flags
& HAMMER_CURSOR_TRACKED
)
652 TAILQ_INSERT_TAIL(&node
->cursor_list
, ncursor
, deadlk_entry
);
653 if ((ip
= ncursor
->ip
) != NULL
) {
654 ++ip
->cursor_ip_refs
;
657 hammer_ref(&ncursor
->iprec
->lock
);
662 * Destroy ncursor and restore ocursor
664 * This is a temporary hack for the release. We can't afford to lose
665 * the IP lock until the IP object scan code is able to deal with it,
666 * so have ocursor inherit it back.
669 hammer_pop_cursor(hammer_cursor_t ocursor
, hammer_cursor_t ncursor
)
674 hmp
= ncursor
->trans
->hmp
;
678 --ip
->cursor_ip_refs
;
679 hammer_done_cursor(ncursor
);
680 kfree(ncursor
, hmp
->m_misc
);
681 KKASSERT(ocursor
->ip
== ip
);
682 hammer_lock_cursor(ocursor
);
686 * onode is being replaced by nnode by the reblocking code.
689 hammer_cursor_replaced_node(hammer_node_t onode
, hammer_node_t nnode
)
691 hammer_cursor_t cursor
;
692 hammer_node_ondisk_t ondisk
;
693 hammer_node_ondisk_t nndisk
;
695 ondisk
= onode
->ondisk
;
696 nndisk
= nnode
->ondisk
;
698 while ((cursor
= TAILQ_FIRST(&onode
->cursor_list
)) != NULL
) {
699 TAILQ_REMOVE(&onode
->cursor_list
, cursor
, deadlk_entry
);
700 TAILQ_INSERT_TAIL(&nnode
->cursor_list
, cursor
, deadlk_entry
);
701 KKASSERT(cursor
->node
== onode
);
702 if (cursor
->leaf
== &ondisk
->elms
[cursor
->index
].leaf
)
703 cursor
->leaf
= &nndisk
->elms
[cursor
->index
].leaf
;
704 cursor
->node
= nnode
;
705 hammer_ref_node(nnode
);
706 hammer_rel_node(onode
);
711 * We have removed <node> from the parent and collapsed the parent.
713 * Cursors in deadlock recovery are seeked upward to the parent so the
714 * btree_remove() recursion works properly even though we have marked
715 * the cursor as requiring a reseek.
717 * This is the only cursor function which sets HAMMER_CURSOR_ITERATE_CHECK,
718 * meaning the cursor is no longer definitively pointing at an element
719 * within its iteration (if the cursor is being used to iterate). The
720 * iteration code will take this into account instead of asserting if the
721 * cursor is outside the iteration range.
724 hammer_cursor_removed_node(hammer_node_t node
, hammer_node_t parent
, int index
)
726 hammer_cursor_t cursor
;
727 hammer_node_ondisk_t ondisk
;
729 KKASSERT(parent
!= NULL
);
730 ondisk
= node
->ondisk
;
732 while ((cursor
= TAILQ_FIRST(&node
->cursor_list
)) != NULL
) {
733 KKASSERT(cursor
->node
== node
);
734 KKASSERT(cursor
->index
== 0);
735 TAILQ_REMOVE(&node
->cursor_list
, cursor
, deadlk_entry
);
736 TAILQ_INSERT_TAIL(&parent
->cursor_list
, cursor
, deadlk_entry
);
737 if (cursor
->leaf
== &ondisk
->elms
[cursor
->index
].leaf
)
739 cursor
->flags
|= HAMMER_CURSOR_TRACKED_RIPOUT
;
740 cursor
->flags
|= HAMMER_CURSOR_ITERATE_CHECK
;
741 cursor
->node
= parent
;
742 cursor
->index
= index
;
743 hammer_ref_node(parent
);
744 hammer_rel_node(node
);
749 * node was split at (onode, index) with elements >= index moved to nnode.
752 hammer_cursor_split_node(hammer_node_t onode
, hammer_node_t nnode
, int index
)
754 hammer_cursor_t cursor
;
755 hammer_node_ondisk_t ondisk
;
756 hammer_node_ondisk_t nndisk
;
758 ondisk
= onode
->ondisk
;
759 nndisk
= nnode
->ondisk
;
762 TAILQ_FOREACH(cursor
, &onode
->cursor_list
, deadlk_entry
) {
763 KKASSERT(cursor
->node
== onode
);
764 if (cursor
->index
< index
)
766 TAILQ_REMOVE(&onode
->cursor_list
, cursor
, deadlk_entry
);
767 TAILQ_INSERT_TAIL(&nnode
->cursor_list
, cursor
, deadlk_entry
);
768 if (cursor
->leaf
== &ondisk
->elms
[cursor
->index
].leaf
)
769 cursor
->leaf
= &nndisk
->elms
[cursor
->index
- index
].leaf
;
770 cursor
->node
= nnode
;
771 cursor
->index
-= index
;
772 hammer_ref_node(nnode
);
773 hammer_rel_node(onode
);
779 * An element was moved from one node to another or within a node. The
780 * index may also represent the end of the node (index == numelements).
782 * {oparent,pindex} is the parent node's pointer to onode/oindex.
784 * This is used by the rebalancing code. This is not an insertion or
785 * deletion and any additional elements, including the degenerate case at
786 * the end of the node, will be dealt with by additional distinct calls.
789 hammer_cursor_moved_element(hammer_node_t oparent
, int pindex
,
790 hammer_node_t onode
, int oindex
,
791 hammer_node_t nnode
, int nindex
)
793 hammer_cursor_t cursor
;
794 hammer_node_ondisk_t ondisk
;
795 hammer_node_ondisk_t nndisk
;
798 * Adjust any cursors pointing at the element
800 ondisk
= onode
->ondisk
;
801 nndisk
= nnode
->ondisk
;
803 TAILQ_FOREACH(cursor
, &onode
->cursor_list
, deadlk_entry
) {
804 KKASSERT(cursor
->node
== onode
);
805 if (cursor
->index
!= oindex
)
807 TAILQ_REMOVE(&onode
->cursor_list
, cursor
, deadlk_entry
);
808 TAILQ_INSERT_TAIL(&nnode
->cursor_list
, cursor
, deadlk_entry
);
809 if (cursor
->leaf
== &ondisk
->elms
[oindex
].leaf
)
810 cursor
->leaf
= &nndisk
->elms
[nindex
].leaf
;
811 cursor
->node
= nnode
;
812 cursor
->index
= nindex
;
813 hammer_ref_node(nnode
);
814 hammer_rel_node(onode
);
819 * When moving the first element of onode to a different node any
820 * cursor which is pointing at (oparent,pindex) must be repointed
821 * to nnode and ATEDISK must be cleared.
823 * This prevents cursors from losing track due to insertions.
824 * Insertions temporarily release the cursor in order to update
825 * the mirror_tids. It primarily effects the mirror_write code.
826 * The other code paths generally only do a single insertion and
827 * then relookup or drop the cursor.
829 if (onode
== nnode
|| oindex
)
831 ondisk
= oparent
->ondisk
;
833 TAILQ_FOREACH(cursor
, &oparent
->cursor_list
, deadlk_entry
) {
834 KKASSERT(cursor
->node
== oparent
);
835 if (cursor
->index
!= pindex
)
837 kprintf("HAMMER debug: shifted cursor pointing at parent\n"
838 "parent %016jx:%d onode %016jx:%d nnode %016jx:%d\n",
839 (intmax_t)oparent
->node_offset
, pindex
,
840 (intmax_t)onode
->node_offset
, oindex
,
841 (intmax_t)nnode
->node_offset
, nindex
);
843 TAILQ_REMOVE(&oparent
->cursor_list
, cursor
, deadlk_entry
);
844 TAILQ_INSERT_TAIL(&nnode
->cursor_list
, cursor
, deadlk_entry
);
845 if (cursor
->leaf
== &ondisk
->elms
[oindex
].leaf
)
846 cursor
->leaf
= &nndisk
->elms
[nindex
].leaf
;
847 cursor
->node
= nnode
;
848 cursor
->index
= nindex
;
849 cursor
->flags
&= ~HAMMER_CURSOR_ATEDISK
;
850 hammer_ref_node(nnode
);
851 hammer_rel_node(oparent
);
857 * The B-Tree element pointing to the specified node was moved from (oparent)
858 * to (nparent, nindex). We must locate any tracked cursors pointing at
859 * node and adjust their parent accordingly.
861 * This is used by the rebalancing code when packing elements causes an
862 * element to shift from one node to another.
865 hammer_cursor_parent_changed(hammer_node_t node
, hammer_node_t oparent
,
866 hammer_node_t nparent
, int nindex
)
868 hammer_cursor_t cursor
;
871 TAILQ_FOREACH(cursor
, &node
->cursor_list
, deadlk_entry
) {
872 KKASSERT(cursor
->node
== node
);
873 if (cursor
->parent
== oparent
) {
874 cursor
->parent
= nparent
;
875 cursor
->parent_index
= nindex
;
876 hammer_ref_node(nparent
);
877 hammer_rel_node(oparent
);
884 * Deleted element at (node, index)
886 * Shift indexes >= index
889 hammer_cursor_deleted_element(hammer_node_t node
, int index
)
891 hammer_cursor_t cursor
;
892 hammer_node_ondisk_t ondisk
;
894 ondisk
= node
->ondisk
;
896 TAILQ_FOREACH(cursor
, &node
->cursor_list
, deadlk_entry
) {
897 KKASSERT(cursor
->node
== node
);
898 if (cursor
->index
== index
) {
899 cursor
->flags
|= HAMMER_CURSOR_TRACKED_RIPOUT
;
900 if (cursor
->leaf
== &ondisk
->elms
[cursor
->index
].leaf
)
902 } else if (cursor
->index
> index
) {
903 if (cursor
->leaf
== &ondisk
->elms
[cursor
->index
].leaf
)
904 cursor
->leaf
= &ondisk
->elms
[cursor
->index
- 1].leaf
;
911 * Inserted element at (node, index)
913 * Shift indexes >= index
916 hammer_cursor_inserted_element(hammer_node_t node
, int index
)
918 hammer_cursor_t cursor
;
919 hammer_node_ondisk_t ondisk
;
921 ondisk
= node
->ondisk
;
923 TAILQ_FOREACH(cursor
, &node
->cursor_list
, deadlk_entry
) {
924 KKASSERT(cursor
->node
== node
);
925 if (cursor
->index
>= index
) {
926 if (cursor
->leaf
== &ondisk
->elms
[cursor
->index
].leaf
)
927 cursor
->leaf
= &ondisk
->elms
[cursor
->index
+ 1].leaf
;