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_btree.c,v 1.56 2008/06/20 05:38:26 dillon Exp $
40 * HAMMER implements a modified B+Tree. In documentation this will
41 * simply be refered to as the HAMMER B-Tree. Basically a HAMMER B-Tree
42 * looks like a B+Tree (A B-Tree which stores its records only at the leafs
43 * of the tree), but adds two additional boundary elements which describe
44 * the left-most and right-most element a node is able to represent. In
45 * otherwords, we have boundary elements at the two ends of a B-Tree node
46 * instead of sub-tree pointers.
48 * A B-Tree internal node looks like this:
50 * B N N N N N N B <-- boundary and internal elements
51 * S S S S S S S <-- subtree pointers
53 * A B-Tree leaf node basically looks like this:
55 * L L L L L L L L <-- leaf elemenets
57 * The radix for an internal node is 1 less then a leaf but we get a
58 * number of significant benefits for our troubles.
60 * The big benefit to using a B-Tree containing boundary information
61 * is that it is possible to cache pointers into the middle of the tree
62 * and not have to start searches, insertions, OR deletions at the root
63 * node. In particular, searches are able to progress in a definitive
64 * direction from any point in the tree without revisting nodes. This
65 * greatly improves the efficiency of many operations, most especially
68 * B-Trees also make the stacking of trees fairly straightforward.
70 * INSERTIONS: A search performed with the intention of doing
71 * an insert will guarantee that the terminal leaf node is not full by
72 * splitting full nodes. Splits occur top-down during the dive down the
75 * DELETIONS: A deletion makes no attempt to proactively balance the
76 * tree and will recursively remove nodes that become empty. If a
77 * deadlock occurs a deletion may not be able to remove an empty leaf.
78 * Deletions never allow internal nodes to become empty (that would blow
85 static int btree_search(hammer_cursor_t cursor
, int flags
);
86 static int btree_split_internal(hammer_cursor_t cursor
);
87 static int btree_split_leaf(hammer_cursor_t cursor
);
88 static int btree_remove(hammer_cursor_t cursor
);
89 static int btree_node_is_full(hammer_node_ondisk_t node
);
90 static void hammer_make_separator(hammer_base_elm_t key1
,
91 hammer_base_elm_t key2
, hammer_base_elm_t dest
);
94 * Iterate records after a search. The cursor is iterated forwards past
95 * the current record until a record matching the key-range requirements
96 * is found. ENOENT is returned if the iteration goes past the ending
99 * The iteration is inclusive of key_beg and can be inclusive or exclusive
100 * of key_end depending on whether HAMMER_CURSOR_END_INCLUSIVE is set.
102 * When doing an as-of search (cursor->asof != 0), key_beg.create_tid
103 * may be modified by B-Tree functions.
105 * cursor->key_beg may or may not be modified by this function during
106 * the iteration. XXX future - in case of an inverted lock we may have
107 * to reinitiate the lookup and set key_beg to properly pick up where we
110 * NOTE! EDEADLK *CANNOT* be returned by this procedure.
113 hammer_btree_iterate(hammer_cursor_t cursor
)
115 hammer_node_ondisk_t node
;
116 hammer_btree_elm_t elm
;
122 * Skip past the current record
124 node
= cursor
->node
->ondisk
;
127 if (cursor
->index
< node
->count
&&
128 (cursor
->flags
& HAMMER_CURSOR_ATEDISK
)) {
133 * Loop until an element is found or we are done.
137 * We iterate up the tree and then index over one element
138 * while we are at the last element in the current node.
140 * If we are at the root of the filesystem, cursor_up
143 * XXX this could be optimized by storing the information in
144 * the parent reference.
146 * XXX we can lose the node lock temporarily, this could mess
149 ++hammer_stats_btree_iterations
;
150 if (cursor
->index
== node
->count
) {
151 if (hammer_debug_btree
) {
152 kprintf("BRACKETU %016llx[%d] -> %016llx[%d] (td=%p)\n",
153 cursor
->node
->node_offset
,
155 (cursor
->parent
? cursor
->parent
->node_offset
: -1),
156 cursor
->parent_index
,
159 KKASSERT(cursor
->parent
== NULL
|| cursor
->parent
->ondisk
->elms
[cursor
->parent_index
].internal
.subtree_offset
== cursor
->node
->node_offset
);
160 error
= hammer_cursor_up(cursor
);
163 /* reload stale pointer */
164 node
= cursor
->node
->ondisk
;
165 KKASSERT(cursor
->index
!= node
->count
);
168 * If we are reblocking we want to return internal
171 if (cursor
->flags
& HAMMER_CURSOR_REBLOCKING
) {
172 cursor
->flags
|= HAMMER_CURSOR_ATEDISK
;
180 * Check internal or leaf element. Determine if the record
181 * at the cursor has gone beyond the end of our range.
183 * We recurse down through internal nodes.
185 if (node
->type
== HAMMER_BTREE_TYPE_INTERNAL
) {
186 elm
= &node
->elms
[cursor
->index
];
187 r
= hammer_btree_cmp(&cursor
->key_end
, &elm
[0].base
);
188 s
= hammer_btree_cmp(&cursor
->key_beg
, &elm
[1].base
);
189 if (hammer_debug_btree
) {
190 kprintf("BRACKETL %016llx[%d] %016llx %02x %016llx lo=%02x %d (td=%p)\n",
191 cursor
->node
->node_offset
,
193 elm
[0].internal
.base
.obj_id
,
194 elm
[0].internal
.base
.rec_type
,
195 elm
[0].internal
.base
.key
,
196 elm
[0].internal
.base
.localization
,
200 kprintf("BRACKETR %016llx[%d] %016llx %02x %016llx lo=%02x %d\n",
201 cursor
->node
->node_offset
,
203 elm
[1].internal
.base
.obj_id
,
204 elm
[1].internal
.base
.rec_type
,
205 elm
[1].internal
.base
.key
,
206 elm
[1].internal
.base
.localization
,
215 if (r
== 0 && (cursor
->flags
&
216 HAMMER_CURSOR_END_INCLUSIVE
) == 0) {
225 KKASSERT(elm
->internal
.subtree_offset
!= 0);
227 error
= hammer_cursor_down(cursor
);
230 KKASSERT(cursor
->index
== 0);
231 /* reload stale pointer */
232 node
= cursor
->node
->ondisk
;
235 elm
= &node
->elms
[cursor
->index
];
236 r
= hammer_btree_cmp(&cursor
->key_end
, &elm
->base
);
237 if (hammer_debug_btree
) {
238 kprintf("ELEMENT %016llx:%d %c %016llx %02x %016llx lo=%02x %d\n",
239 cursor
->node
->node_offset
,
241 (elm
[0].leaf
.base
.btype
?
242 elm
[0].leaf
.base
.btype
: '?'),
243 elm
[0].leaf
.base
.obj_id
,
244 elm
[0].leaf
.base
.rec_type
,
245 elm
[0].leaf
.base
.key
,
246 elm
[0].leaf
.base
.localization
,
256 * We support both end-inclusive and
257 * end-exclusive searches.
260 (cursor
->flags
& HAMMER_CURSOR_END_INCLUSIVE
) == 0) {
265 switch(elm
->leaf
.base
.btype
) {
266 case HAMMER_BTREE_TYPE_RECORD
:
267 if ((cursor
->flags
& HAMMER_CURSOR_ASOF
) &&
268 hammer_btree_chkts(cursor
->asof
, &elm
->base
)) {
281 * node pointer invalid after loop
287 if (hammer_debug_btree
) {
288 int i
= cursor
->index
;
289 hammer_btree_elm_t elm
= &cursor
->node
->ondisk
->elms
[i
];
290 kprintf("ITERATE %p:%d %016llx %02x %016llx lo=%02x\n",
292 elm
->internal
.base
.obj_id
,
293 elm
->internal
.base
.rec_type
,
294 elm
->internal
.base
.key
,
295 elm
->internal
.base
.localization
304 * Iterate in the reverse direction. This is used by the pruning code to
305 * avoid overlapping records.
308 hammer_btree_iterate_reverse(hammer_cursor_t cursor
)
310 hammer_node_ondisk_t node
;
311 hammer_btree_elm_t elm
;
317 * Skip past the current record. For various reasons the cursor
318 * may end up set to -1 or set to point at the end of the current
319 * node. These cases must be addressed.
321 node
= cursor
->node
->ondisk
;
324 if (cursor
->index
!= -1 &&
325 (cursor
->flags
& HAMMER_CURSOR_ATEDISK
)) {
328 if (cursor
->index
== cursor
->node
->ondisk
->count
)
332 * Loop until an element is found or we are done.
336 * We iterate up the tree and then index over one element
337 * while we are at the last element in the current node.
339 if (cursor
->index
== -1) {
340 error
= hammer_cursor_up(cursor
);
342 cursor
->index
= 0; /* sanity */
345 /* reload stale pointer */
346 node
= cursor
->node
->ondisk
;
347 KKASSERT(cursor
->index
!= node
->count
);
353 * Check internal or leaf element. Determine if the record
354 * at the cursor has gone beyond the end of our range.
356 * We recurse down through internal nodes.
358 KKASSERT(cursor
->index
!= node
->count
);
359 if (node
->type
== HAMMER_BTREE_TYPE_INTERNAL
) {
360 elm
= &node
->elms
[cursor
->index
];
361 r
= hammer_btree_cmp(&cursor
->key_end
, &elm
[0].base
);
362 s
= hammer_btree_cmp(&cursor
->key_beg
, &elm
[1].base
);
363 if (hammer_debug_btree
) {
364 kprintf("BRACKETL %016llx[%d] %016llx %02x %016llx lo=%02x %d\n",
365 cursor
->node
->node_offset
,
367 elm
[0].internal
.base
.obj_id
,
368 elm
[0].internal
.base
.rec_type
,
369 elm
[0].internal
.base
.key
,
370 elm
[0].internal
.base
.localization
,
373 kprintf("BRACKETR %016llx[%d] %016llx %02x %016llx lo=%02x %d\n",
374 cursor
->node
->node_offset
,
376 elm
[1].internal
.base
.obj_id
,
377 elm
[1].internal
.base
.rec_type
,
378 elm
[1].internal
.base
.key
,
379 elm
[1].internal
.base
.localization
,
393 KKASSERT(elm
->internal
.subtree_offset
!= 0);
395 error
= hammer_cursor_down(cursor
);
398 KKASSERT(cursor
->index
== 0);
399 /* reload stale pointer */
400 node
= cursor
->node
->ondisk
;
402 /* this can assign -1 if the leaf was empty */
403 cursor
->index
= node
->count
- 1;
406 elm
= &node
->elms
[cursor
->index
];
407 s
= hammer_btree_cmp(&cursor
->key_beg
, &elm
->base
);
408 if (hammer_debug_btree
) {
409 kprintf("ELEMENT %016llx:%d %c %016llx %02x %016llx lo=%02x %d\n",
410 cursor
->node
->node_offset
,
412 (elm
[0].leaf
.base
.btype
?
413 elm
[0].leaf
.base
.btype
: '?'),
414 elm
[0].leaf
.base
.obj_id
,
415 elm
[0].leaf
.base
.rec_type
,
416 elm
[0].leaf
.base
.key
,
417 elm
[0].leaf
.base
.localization
,
426 switch(elm
->leaf
.base
.btype
) {
427 case HAMMER_BTREE_TYPE_RECORD
:
428 if ((cursor
->flags
& HAMMER_CURSOR_ASOF
) &&
429 hammer_btree_chkts(cursor
->asof
, &elm
->base
)) {
442 * node pointer invalid after loop
448 if (hammer_debug_btree
) {
449 int i
= cursor
->index
;
450 hammer_btree_elm_t elm
= &cursor
->node
->ondisk
->elms
[i
];
451 kprintf("ITERATE %p:%d %016llx %02x %016llx lo=%02x\n",
453 elm
->internal
.base
.obj_id
,
454 elm
->internal
.base
.rec_type
,
455 elm
->internal
.base
.key
,
456 elm
->internal
.base
.localization
465 * Lookup cursor->key_beg. 0 is returned on success, ENOENT if the entry
466 * could not be found, EDEADLK if inserting and a retry is needed, and a
467 * fatal error otherwise. When retrying, the caller must terminate the
468 * cursor and reinitialize it. EDEADLK cannot be returned if not inserting.
470 * The cursor is suitably positioned for a deletion on success, and suitably
471 * positioned for an insertion on ENOENT if HAMMER_CURSOR_INSERT was
474 * The cursor may begin anywhere, the search will traverse the tree in
475 * either direction to locate the requested element.
477 * Most of the logic implementing historical searches is handled here. We
478 * do an initial lookup with create_tid set to the asof TID. Due to the
479 * way records are laid out, a backwards iteration may be required if
480 * ENOENT is returned to locate the historical record. Here's the
483 * create_tid: 10 15 20
487 * Lets say we want to do a lookup AS-OF timestamp 17. We will traverse
488 * LEAF2 but the only record in LEAF2 has a create_tid of 18, which is
489 * not visible and thus causes ENOENT to be returned. We really need
490 * to check record 11 in LEAF1. If it also fails then the search fails
491 * (e.g. it might represent the range 11-16 and thus still not match our
492 * AS-OF timestamp of 17). Note that LEAF1 could be empty, requiring
493 * further iterations.
495 * If this case occurs btree_search() will set HAMMER_CURSOR_CREATE_CHECK
496 * and the cursor->create_check TID if an iteration might be needed.
497 * In the above example create_check would be set to 14.
500 hammer_btree_lookup(hammer_cursor_t cursor
)
504 ++hammer_stats_btree_lookups
;
505 if (cursor
->flags
& HAMMER_CURSOR_ASOF
) {
506 KKASSERT((cursor
->flags
& HAMMER_CURSOR_INSERT
) == 0);
507 cursor
->key_beg
.create_tid
= cursor
->asof
;
509 cursor
->flags
&= ~HAMMER_CURSOR_CREATE_CHECK
;
510 error
= btree_search(cursor
, 0);
511 if (error
!= ENOENT
||
512 (cursor
->flags
& HAMMER_CURSOR_CREATE_CHECK
) == 0) {
515 * Stop if error other then ENOENT.
516 * Stop if ENOENT and not special case.
520 if (hammer_debug_btree
) {
521 kprintf("CREATE_CHECK %016llx\n",
522 cursor
->create_check
);
524 cursor
->key_beg
.create_tid
= cursor
->create_check
;
528 error
= btree_search(cursor
, 0);
531 error
= hammer_btree_extract(cursor
, cursor
->flags
);
536 * Execute the logic required to start an iteration. The first record
537 * located within the specified range is returned and iteration control
538 * flags are adjusted for successive hammer_btree_iterate() calls.
541 hammer_btree_first(hammer_cursor_t cursor
)
545 error
= hammer_btree_lookup(cursor
);
546 if (error
== ENOENT
) {
547 cursor
->flags
&= ~HAMMER_CURSOR_ATEDISK
;
548 error
= hammer_btree_iterate(cursor
);
550 cursor
->flags
|= HAMMER_CURSOR_ATEDISK
;
555 * Similarly but for an iteration in the reverse direction.
557 * Set ATEDISK when iterating backwards to skip the current entry,
558 * which after an ENOENT lookup will be pointing beyond our end point.
561 hammer_btree_last(hammer_cursor_t cursor
)
563 struct hammer_base_elm save
;
566 save
= cursor
->key_beg
;
567 cursor
->key_beg
= cursor
->key_end
;
568 error
= hammer_btree_lookup(cursor
);
569 cursor
->key_beg
= save
;
570 if (error
== ENOENT
||
571 (cursor
->flags
& HAMMER_CURSOR_END_INCLUSIVE
) == 0) {
572 cursor
->flags
|= HAMMER_CURSOR_ATEDISK
;
573 error
= hammer_btree_iterate_reverse(cursor
);
575 cursor
->flags
|= HAMMER_CURSOR_ATEDISK
;
580 * Extract the record and/or data associated with the cursor's current
581 * position. Any prior record or data stored in the cursor is replaced.
582 * The cursor must be positioned at a leaf node.
584 * NOTE: All extractions occur at the leaf of the B-Tree.
587 hammer_btree_extract(hammer_cursor_t cursor
, int flags
)
590 hammer_node_ondisk_t node
;
591 hammer_btree_elm_t elm
;
592 hammer_off_t data_off
;
597 * The case where the data reference resolves to the same buffer
598 * as the record reference must be handled.
600 node
= cursor
->node
->ondisk
;
601 elm
= &node
->elms
[cursor
->index
];
603 hmp
= cursor
->node
->hmp
;
606 * There is nothing to extract for an internal element.
608 if (node
->type
== HAMMER_BTREE_TYPE_INTERNAL
)
612 * Only record types have data.
614 KKASSERT(node
->type
== HAMMER_BTREE_TYPE_LEAF
);
615 cursor
->leaf
= &elm
->leaf
;
617 if ((flags
& HAMMER_CURSOR_GET_DATA
) == 0)
619 if (elm
->leaf
.base
.btype
!= HAMMER_BTREE_TYPE_RECORD
)
621 data_off
= elm
->leaf
.data_offset
;
622 data_len
= elm
->leaf
.data_len
;
629 KKASSERT(data_len
>= 0 && data_len
<= HAMMER_XBUFSIZE
);
630 cursor
->data
= hammer_bread_ext(hmp
, data_off
, data_len
,
631 &error
, &cursor
->data_buffer
);
633 crc32(cursor
->data
, data_len
) != elm
->leaf
.data_crc
) {
634 Debugger("CRC FAILED: DATA");
641 * Insert a leaf element into the B-Tree at the current cursor position.
642 * The cursor is positioned such that the element at and beyond the cursor
643 * are shifted to make room for the new record.
645 * The caller must call hammer_btree_lookup() with the HAMMER_CURSOR_INSERT
646 * flag set and that call must return ENOENT before this function can be
649 * The caller may depend on the cursor's exclusive lock after return to
650 * interlock frontend visibility (see HAMMER_RECF_CONVERT_DELETE).
652 * ENOSPC is returned if there is no room to insert a new record.
655 hammer_btree_insert(hammer_cursor_t cursor
, hammer_btree_leaf_elm_t elm
)
657 hammer_node_ondisk_t node
;
661 if ((error
= hammer_cursor_upgrade_node(cursor
)) != 0)
663 ++hammer_stats_btree_inserts
;
666 * Insert the element at the leaf node and update the count in the
667 * parent. It is possible for parent to be NULL, indicating that
668 * the filesystem's ROOT B-Tree node is a leaf itself, which is
669 * possible. The root inode can never be deleted so the leaf should
672 * Remember that the right-hand boundary is not included in the
675 hammer_modify_node_all(cursor
->trans
, cursor
->node
);
676 node
= cursor
->node
->ondisk
;
678 KKASSERT(elm
->base
.btype
!= 0);
679 KKASSERT(node
->type
== HAMMER_BTREE_TYPE_LEAF
);
680 KKASSERT(node
->count
< HAMMER_BTREE_LEAF_ELMS
);
681 if (i
!= node
->count
) {
682 bcopy(&node
->elms
[i
], &node
->elms
[i
+1],
683 (node
->count
- i
) * sizeof(*elm
));
685 node
->elms
[i
].leaf
= *elm
;
687 hammer_modify_node_done(cursor
->node
);
690 * Debugging sanity checks.
692 KKASSERT(hammer_btree_cmp(cursor
->left_bound
, &elm
->base
) <= 0);
693 KKASSERT(hammer_btree_cmp(cursor
->right_bound
, &elm
->base
) > 0);
695 KKASSERT(hammer_btree_cmp(&node
->elms
[i
-1].leaf
.base
, &elm
->base
) < 0);
697 if (i
!= node
->count
- 1)
698 KKASSERT(hammer_btree_cmp(&node
->elms
[i
+1].leaf
.base
, &elm
->base
) > 0);
704 * Delete a record from the B-Tree at the current cursor position.
705 * The cursor is positioned such that the current element is the one
708 * On return the cursor will be positioned after the deleted element and
709 * MAY point to an internal node. It will be suitable for the continuation
710 * of an iteration but not for an insertion or deletion.
712 * Deletions will attempt to partially rebalance the B-Tree in an upward
713 * direction, but will terminate rather then deadlock. Empty internal nodes
714 * are never allowed by a deletion which deadlocks may end up giving us an
715 * empty leaf. The pruner will clean up and rebalance the tree.
717 * This function can return EDEADLK, requiring the caller to retry the
718 * operation after clearing the deadlock.
721 hammer_btree_delete(hammer_cursor_t cursor
)
723 hammer_node_ondisk_t ondisk
;
725 hammer_node_t parent
;
729 if ((error
= hammer_cursor_upgrade(cursor
)) != 0)
731 ++hammer_stats_btree_deletes
;
734 * Delete the element from the leaf node.
736 * Remember that leaf nodes do not have boundaries.
739 ondisk
= node
->ondisk
;
742 KKASSERT(ondisk
->type
== HAMMER_BTREE_TYPE_LEAF
);
743 KKASSERT(i
>= 0 && i
< ondisk
->count
);
744 hammer_modify_node_all(cursor
->trans
, node
);
745 if (i
+ 1 != ondisk
->count
) {
746 bcopy(&ondisk
->elms
[i
+1], &ondisk
->elms
[i
],
747 (ondisk
->count
- i
- 1) * sizeof(ondisk
->elms
[0]));
750 hammer_modify_node_done(node
);
753 * Validate local parent
755 if (ondisk
->parent
) {
756 parent
= cursor
->parent
;
758 KKASSERT(parent
!= NULL
);
759 KKASSERT(parent
->node_offset
== ondisk
->parent
);
763 * If the leaf becomes empty it must be detached from the parent,
764 * potentially recursing through to the filesystem root.
766 * This may reposition the cursor at one of the parent's of the
769 * Ignore deadlock errors, that simply means that btree_remove
770 * was unable to recurse and had to leave us with an empty leaf.
772 KKASSERT(cursor
->index
<= ondisk
->count
);
773 if (ondisk
->count
== 0) {
774 error
= btree_remove(cursor
);
775 if (error
== EDEADLK
)
780 KKASSERT(cursor
->parent
== NULL
||
781 cursor
->parent_index
< cursor
->parent
->ondisk
->count
);
786 * PRIMAY B-TREE SEARCH SUPPORT PROCEDURE
788 * Search the filesystem B-Tree for cursor->key_beg, return the matching node.
790 * The search can begin ANYWHERE in the B-Tree. As a first step the search
791 * iterates up the tree as necessary to properly position itself prior to
792 * actually doing the sarch.
794 * INSERTIONS: The search will split full nodes and leaves on its way down
795 * and guarentee that the leaf it ends up on is not full. If we run out
796 * of space the search continues to the leaf (to position the cursor for
797 * the spike), but ENOSPC is returned.
799 * The search is only guarenteed to end up on a leaf if an error code of 0
800 * is returned, or if inserting and an error code of ENOENT is returned.
801 * Otherwise it can stop at an internal node. On success a search returns
804 * COMPLEXITY WARNING! This is the core B-Tree search code for the entire
805 * filesystem, and it is not simple code. Please note the following facts:
807 * - Internal node recursions have a boundary on the left AND right. The
808 * right boundary is non-inclusive. The create_tid is a generic part
809 * of the key for internal nodes.
811 * - Leaf nodes contain terminal elements only now.
813 * - Filesystem lookups typically set HAMMER_CURSOR_ASOF, indicating a
814 * historical search. ASOF and INSERT are mutually exclusive. When
815 * doing an as-of lookup btree_search() checks for a right-edge boundary
816 * case. If while recursing down the left-edge differs from the key
817 * by ONLY its create_tid, HAMMER_CURSOR_CREATE_CHECK is set along
818 * with cursor->create_check. This is used by btree_lookup() to iterate.
819 * The iteration backwards because as-of searches can wind up going
820 * down the wrong branch of the B-Tree.
824 btree_search(hammer_cursor_t cursor
, int flags
)
826 hammer_node_ondisk_t node
;
827 hammer_btree_elm_t elm
;
834 flags
|= cursor
->flags
;
835 ++hammer_stats_btree_searches
;
837 if (hammer_debug_btree
) {
838 kprintf("SEARCH %016llx[%d] %016llx %02x key=%016llx cre=%016llx lo=%02x (td = %p)\n",
839 cursor
->node
->node_offset
,
841 cursor
->key_beg
.obj_id
,
842 cursor
->key_beg
.rec_type
,
844 cursor
->key_beg
.create_tid
,
845 cursor
->key_beg
.localization
,
849 kprintf("SEARCHP %016llx[%d] (%016llx/%016llx %016llx/%016llx) (%p/%p %p/%p)\n",
850 cursor
->parent
->node_offset
, cursor
->parent_index
,
851 cursor
->left_bound
->obj_id
,
852 cursor
->parent
->ondisk
->elms
[cursor
->parent_index
].internal
.base
.obj_id
,
853 cursor
->right_bound
->obj_id
,
854 cursor
->parent
->ondisk
->elms
[cursor
->parent_index
+1].internal
.base
.obj_id
,
856 &cursor
->parent
->ondisk
->elms
[cursor
->parent_index
],
858 &cursor
->parent
->ondisk
->elms
[cursor
->parent_index
+1]
863 * Move our cursor up the tree until we find a node whos range covers
864 * the key we are trying to locate.
866 * The left bound is inclusive, the right bound is non-inclusive.
867 * It is ok to cursor up too far.
870 r
= hammer_btree_cmp(&cursor
->key_beg
, cursor
->left_bound
);
871 s
= hammer_btree_cmp(&cursor
->key_beg
, cursor
->right_bound
);
874 KKASSERT(cursor
->parent
);
875 ++hammer_stats_btree_iterations
;
876 error
= hammer_cursor_up(cursor
);
882 * The delete-checks below are based on node, not parent. Set the
883 * initial delete-check based on the parent.
886 KKASSERT(cursor
->left_bound
->create_tid
!= 1);
887 cursor
->create_check
= cursor
->left_bound
->create_tid
- 1;
888 cursor
->flags
|= HAMMER_CURSOR_CREATE_CHECK
;
892 * We better have ended up with a node somewhere.
894 KKASSERT(cursor
->node
!= NULL
);
897 * If we are inserting we can't start at a full node if the parent
898 * is also full (because there is no way to split the node),
899 * continue running up the tree until the requirement is satisfied
900 * or we hit the root of the filesystem.
902 * (If inserting we aren't doing an as-of search so we don't have
903 * to worry about create_check).
905 while ((flags
& HAMMER_CURSOR_INSERT
) && enospc
== 0) {
906 if (cursor
->node
->ondisk
->type
== HAMMER_BTREE_TYPE_INTERNAL
) {
907 if (btree_node_is_full(cursor
->node
->ondisk
) == 0)
910 if (btree_node_is_full(cursor
->node
->ondisk
) ==0)
913 if (cursor
->node
->ondisk
->parent
== 0 ||
914 cursor
->parent
->ondisk
->count
!= HAMMER_BTREE_INT_ELMS
) {
917 ++hammer_stats_btree_iterations
;
918 error
= hammer_cursor_up(cursor
);
919 /* node may have become stale */
925 * Push down through internal nodes to locate the requested key.
927 node
= cursor
->node
->ondisk
;
928 while (node
->type
== HAMMER_BTREE_TYPE_INTERNAL
) {
930 * Scan the node to find the subtree index to push down into.
931 * We go one-past, then back-up.
933 * We must proactively remove deleted elements which may
934 * have been left over from a deadlocked btree_remove().
936 * The left and right boundaries are included in the loop
937 * in order to detect edge cases.
939 * If the separator only differs by create_tid (r == 1)
940 * and we are doing an as-of search, we may end up going
941 * down a branch to the left of the one containing the
942 * desired key. This requires numerous special cases.
944 ++hammer_stats_btree_iterations
;
945 if (hammer_debug_btree
) {
946 kprintf("SEARCH-I %016llx count=%d\n",
947 cursor
->node
->node_offset
,
952 * Try to shortcut the search before dropping into the
953 * linear loop. Locate the first node where r <= 1.
955 i
= hammer_btree_search_node(&cursor
->key_beg
, node
);
956 while (i
<= node
->count
) {
957 ++hammer_stats_btree_elements
;
958 elm
= &node
->elms
[i
];
959 r
= hammer_btree_cmp(&cursor
->key_beg
, &elm
->base
);
960 if (hammer_debug_btree
> 2) {
961 kprintf(" IELM %p %d r=%d\n",
962 &node
->elms
[i
], i
, r
);
967 KKASSERT(elm
->base
.create_tid
!= 1);
968 cursor
->create_check
= elm
->base
.create_tid
- 1;
969 cursor
->flags
|= HAMMER_CURSOR_CREATE_CHECK
;
973 if (hammer_debug_btree
) {
974 kprintf("SEARCH-I preI=%d/%d r=%d\n",
979 * These cases occur when the parent's idea of the boundary
980 * is wider then the child's idea of the boundary, and
981 * require special handling. If not inserting we can
982 * terminate the search early for these cases but the
983 * child's boundaries cannot be unconditionally modified.
987 * If i == 0 the search terminated to the LEFT of the
988 * left_boundary but to the RIGHT of the parent's left
993 elm
= &node
->elms
[0];
996 * If we aren't inserting we can stop here.
998 if ((flags
& (HAMMER_CURSOR_INSERT
|
999 HAMMER_CURSOR_PRUNING
)) == 0) {
1005 * Correct a left-hand boundary mismatch.
1007 * We can only do this if we can upgrade the lock,
1008 * and synchronized as a background cursor (i.e.
1009 * inserting or pruning).
1011 * WARNING: We can only do this if inserting, i.e.
1012 * we are running on the backend.
1014 if ((error
= hammer_cursor_upgrade(cursor
)) != 0)
1016 KKASSERT(cursor
->flags
& HAMMER_CURSOR_BACKEND
);
1017 hammer_modify_node_field(cursor
->trans
, cursor
->node
,
1019 save
= node
->elms
[0].base
.btype
;
1020 node
->elms
[0].base
= *cursor
->left_bound
;
1021 node
->elms
[0].base
.btype
= save
;
1022 hammer_modify_node_done(cursor
->node
);
1023 } else if (i
== node
->count
+ 1) {
1025 * If i == node->count + 1 the search terminated to
1026 * the RIGHT of the right boundary but to the LEFT
1027 * of the parent's right boundary. If we aren't
1028 * inserting we can stop here.
1030 * Note that the last element in this case is
1031 * elms[i-2] prior to adjustments to 'i'.
1034 if ((flags
& (HAMMER_CURSOR_INSERT
|
1035 HAMMER_CURSOR_PRUNING
)) == 0) {
1041 * Correct a right-hand boundary mismatch.
1042 * (actual push-down record is i-2 prior to
1043 * adjustments to i).
1045 * We can only do this if we can upgrade the lock,
1046 * and synchronized as a background cursor (i.e.
1047 * inserting or pruning).
1049 * WARNING: We can only do this if inserting, i.e.
1050 * we are running on the backend.
1052 if ((error
= hammer_cursor_upgrade(cursor
)) != 0)
1054 elm
= &node
->elms
[i
];
1055 KKASSERT(cursor
->flags
& HAMMER_CURSOR_BACKEND
);
1056 hammer_modify_node(cursor
->trans
, cursor
->node
,
1057 &elm
->base
, sizeof(elm
->base
));
1058 elm
->base
= *cursor
->right_bound
;
1059 hammer_modify_node_done(cursor
->node
);
1063 * The push-down index is now i - 1. If we had
1064 * terminated on the right boundary this will point
1065 * us at the last element.
1070 elm
= &node
->elms
[i
];
1072 if (hammer_debug_btree
) {
1073 kprintf("RESULT-I %016llx[%d] %016llx %02x "
1074 "key=%016llx cre=%016llx lo=%02x\n",
1075 cursor
->node
->node_offset
,
1077 elm
->internal
.base
.obj_id
,
1078 elm
->internal
.base
.rec_type
,
1079 elm
->internal
.base
.key
,
1080 elm
->internal
.base
.create_tid
,
1081 elm
->internal
.base
.localization
1086 * We better have a valid subtree offset.
1088 KKASSERT(elm
->internal
.subtree_offset
!= 0);
1091 * Handle insertion and deletion requirements.
1093 * If inserting split full nodes. The split code will
1094 * adjust cursor->node and cursor->index if the current
1095 * index winds up in the new node.
1097 * If inserting and a left or right edge case was detected,
1098 * we cannot correct the left or right boundary and must
1099 * prepend and append an empty leaf node in order to make
1100 * the boundary correction.
1102 * If we run out of space we set enospc and continue on
1103 * to a leaf to provide the spike code with a good point
1106 if ((flags
& HAMMER_CURSOR_INSERT
) && enospc
== 0) {
1107 if (btree_node_is_full(node
)) {
1108 error
= btree_split_internal(cursor
);
1110 if (error
!= ENOSPC
)
1115 * reload stale pointers
1118 node
= cursor
->node
->ondisk
;
1123 * Push down (push into new node, existing node becomes
1124 * the parent) and continue the search.
1126 error
= hammer_cursor_down(cursor
);
1127 /* node may have become stale */
1130 node
= cursor
->node
->ondisk
;
1134 * We are at a leaf, do a linear search of the key array.
1136 * On success the index is set to the matching element and 0
1139 * On failure the index is set to the insertion point and ENOENT
1142 * Boundaries are not stored in leaf nodes, so the index can wind
1143 * up to the left of element 0 (index == 0) or past the end of
1144 * the array (index == node->count). It is also possible that the
1145 * leaf might be empty.
1147 ++hammer_stats_btree_iterations
;
1148 KKASSERT (node
->type
== HAMMER_BTREE_TYPE_LEAF
);
1149 KKASSERT(node
->count
<= HAMMER_BTREE_LEAF_ELMS
);
1150 if (hammer_debug_btree
) {
1151 kprintf("SEARCH-L %016llx count=%d\n",
1152 cursor
->node
->node_offset
,
1157 * Try to shortcut the search before dropping into the
1158 * linear loop. Locate the first node where r <= 1.
1160 i
= hammer_btree_search_node(&cursor
->key_beg
, node
);
1161 while (i
< node
->count
) {
1162 ++hammer_stats_btree_elements
;
1163 elm
= &node
->elms
[i
];
1165 r
= hammer_btree_cmp(&cursor
->key_beg
, &elm
->leaf
.base
);
1167 if (hammer_debug_btree
> 1)
1168 kprintf(" ELM %p %d r=%d\n", &node
->elms
[i
], i
, r
);
1171 * We are at a record element. Stop if we've flipped past
1172 * key_beg, not counting the create_tid test. Allow the
1173 * r == 1 case (key_beg > element but differs only by its
1174 * create_tid) to fall through to the AS-OF check.
1176 KKASSERT (elm
->leaf
.base
.btype
== HAMMER_BTREE_TYPE_RECORD
);
1186 * Check our as-of timestamp against the element.
1188 if (flags
& HAMMER_CURSOR_ASOF
) {
1189 if (hammer_btree_chkts(cursor
->asof
,
1190 &node
->elms
[i
].base
) != 0) {
1196 if (r
> 0) { /* can only be +1 */
1204 if (hammer_debug_btree
) {
1205 kprintf("RESULT-L %016llx[%d] (SUCCESS)\n",
1206 cursor
->node
->node_offset
, i
);
1212 * The search of the leaf node failed. i is the insertion point.
1215 if (hammer_debug_btree
) {
1216 kprintf("RESULT-L %016llx[%d] (FAILED)\n",
1217 cursor
->node
->node_offset
, i
);
1221 * No exact match was found, i is now at the insertion point.
1223 * If inserting split a full leaf before returning. This
1224 * may have the side effect of adjusting cursor->node and
1228 if ((flags
& HAMMER_CURSOR_INSERT
) && enospc
== 0 &&
1229 btree_node_is_full(node
)) {
1230 error
= btree_split_leaf(cursor
);
1232 if (error
!= ENOSPC
)
1237 * reload stale pointers
1241 node = &cursor->node->internal;
1246 * We reached a leaf but did not find the key we were looking for.
1247 * If this is an insert we will be properly positioned for an insert
1248 * (ENOENT) or spike (ENOSPC) operation.
1250 error
= enospc
? ENOSPC
: ENOENT
;
1256 * Heuristical search for the first element whos comparison is <= 1. May
1257 * return an index whos compare result is > 1 but may only return an index
1258 * whos compare result is <= 1 if it is the first element with that result.
1261 hammer_btree_search_node(hammer_base_elm_t elm
, hammer_node_ondisk_t node
)
1269 * Don't bother if the node does not have very many elements
1274 i
= b
+ (s
- b
) / 2;
1275 ++hammer_stats_btree_elements
;
1276 r
= hammer_btree_cmp(elm
, &node
->elms
[i
].leaf
.base
);
1287 /************************************************************************
1288 * SPLITTING AND MERGING *
1289 ************************************************************************
1291 * These routines do all the dirty work required to split and merge nodes.
1295 * Split an internal node into two nodes and move the separator at the split
1296 * point to the parent.
1298 * (cursor->node, cursor->index) indicates the element the caller intends
1299 * to push into. We will adjust node and index if that element winds
1300 * up in the split node.
1302 * If we are at the root of the filesystem a new root must be created with
1303 * two elements, one pointing to the original root and one pointing to the
1304 * newly allocated split node.
1308 btree_split_internal(hammer_cursor_t cursor
)
1310 hammer_node_ondisk_t ondisk
;
1312 hammer_node_t parent
;
1313 hammer_node_t new_node
;
1314 hammer_btree_elm_t elm
;
1315 hammer_btree_elm_t parent_elm
;
1316 hammer_node_locklist_t locklist
= NULL
;
1317 hammer_mount_t hmp
= cursor
->trans
->hmp
;
1323 const int esize
= sizeof(*elm
);
1325 error
= hammer_btree_lock_children(cursor
, &locklist
);
1328 if ((error
= hammer_cursor_upgrade(cursor
)) != 0)
1330 ++hammer_stats_btree_splits
;
1333 * We are splitting but elms[split] will be promoted to the parent,
1334 * leaving the right hand node with one less element. If the
1335 * insertion point will be on the left-hand side adjust the split
1336 * point to give the right hand side one additional node.
1338 node
= cursor
->node
;
1339 ondisk
= node
->ondisk
;
1340 split
= (ondisk
->count
+ 1) / 2;
1341 if (cursor
->index
<= split
)
1345 * If we are at the root of the filesystem, create a new root node
1346 * with 1 element and split normally. Avoid making major
1347 * modifications until we know the whole operation will work.
1349 if (ondisk
->parent
== 0) {
1350 parent
= hammer_alloc_btree(cursor
->trans
, &error
);
1353 hammer_lock_ex(&parent
->lock
);
1354 hammer_modify_node_noundo(cursor
->trans
, parent
);
1355 ondisk
= parent
->ondisk
;
1358 ondisk
->type
= HAMMER_BTREE_TYPE_INTERNAL
;
1359 ondisk
->elms
[0].base
= hmp
->root_btree_beg
;
1360 ondisk
->elms
[0].base
.btype
= node
->ondisk
->type
;
1361 ondisk
->elms
[0].internal
.subtree_offset
= node
->node_offset
;
1362 ondisk
->elms
[1].base
= hmp
->root_btree_end
;
1363 hammer_modify_node_done(parent
);
1364 /* ondisk->elms[1].base.btype - not used */
1366 parent_index
= 0; /* index of current node in parent */
1369 parent
= cursor
->parent
;
1370 parent_index
= cursor
->parent_index
;
1374 * Split node into new_node at the split point.
1376 * B O O O P N N B <-- P = node->elms[split]
1377 * 0 1 2 3 4 5 6 <-- subtree indices
1382 * B O O O B B N N B <--- inner boundary points are 'P'
1386 new_node
= hammer_alloc_btree(cursor
->trans
, &error
);
1387 if (new_node
== NULL
) {
1389 hammer_unlock(&parent
->lock
);
1390 hammer_delete_node(cursor
->trans
, parent
);
1391 hammer_rel_node(parent
);
1395 hammer_lock_ex(&new_node
->lock
);
1398 * Create the new node. P becomes the left-hand boundary in the
1399 * new node. Copy the right-hand boundary as well.
1401 * elm is the new separator.
1403 hammer_modify_node_noundo(cursor
->trans
, new_node
);
1404 hammer_modify_node_all(cursor
->trans
, node
);
1405 ondisk
= node
->ondisk
;
1406 elm
= &ondisk
->elms
[split
];
1407 bcopy(elm
, &new_node
->ondisk
->elms
[0],
1408 (ondisk
->count
- split
+ 1) * esize
);
1409 new_node
->ondisk
->count
= ondisk
->count
- split
;
1410 new_node
->ondisk
->parent
= parent
->node_offset
;
1411 new_node
->ondisk
->type
= HAMMER_BTREE_TYPE_INTERNAL
;
1412 KKASSERT(ondisk
->type
== new_node
->ondisk
->type
);
1415 * Cleanup the original node. Elm (P) becomes the new boundary,
1416 * its subtree_offset was moved to the new node. If we had created
1417 * a new root its parent pointer may have changed.
1419 elm
->internal
.subtree_offset
= 0;
1420 ondisk
->count
= split
;
1423 * Insert the separator into the parent, fixup the parent's
1424 * reference to the original node, and reference the new node.
1425 * The separator is P.
1427 * Remember that base.count does not include the right-hand boundary.
1429 hammer_modify_node_all(cursor
->trans
, parent
);
1430 ondisk
= parent
->ondisk
;
1431 KKASSERT(ondisk
->count
!= HAMMER_BTREE_INT_ELMS
);
1432 parent_elm
= &ondisk
->elms
[parent_index
+1];
1433 bcopy(parent_elm
, parent_elm
+ 1,
1434 (ondisk
->count
- parent_index
) * esize
);
1435 parent_elm
->internal
.base
= elm
->base
; /* separator P */
1436 parent_elm
->internal
.base
.btype
= new_node
->ondisk
->type
;
1437 parent_elm
->internal
.subtree_offset
= new_node
->node_offset
;
1439 hammer_modify_node_done(parent
);
1442 * The children of new_node need their parent pointer set to new_node.
1443 * The children have already been locked by
1444 * hammer_btree_lock_children().
1446 for (i
= 0; i
< new_node
->ondisk
->count
; ++i
) {
1447 elm
= &new_node
->ondisk
->elms
[i
];
1448 error
= btree_set_parent(cursor
->trans
, new_node
, elm
);
1450 panic("btree_split_internal: btree-fixup problem");
1453 hammer_modify_node_done(new_node
);
1456 * The filesystem's root B-Tree pointer may have to be updated.
1459 hammer_volume_t volume
;
1461 volume
= hammer_get_root_volume(hmp
, &error
);
1462 KKASSERT(error
== 0);
1464 hammer_modify_volume_field(cursor
->trans
, volume
,
1466 volume
->ondisk
->vol0_btree_root
= parent
->node_offset
;
1467 hammer_modify_volume_done(volume
);
1468 node
->ondisk
->parent
= parent
->node_offset
;
1469 if (cursor
->parent
) {
1470 hammer_unlock(&cursor
->parent
->lock
);
1471 hammer_rel_node(cursor
->parent
);
1473 cursor
->parent
= parent
; /* lock'd and ref'd */
1474 hammer_rel_volume(volume
, 0);
1476 hammer_modify_node_done(node
);
1480 * Ok, now adjust the cursor depending on which element the original
1481 * index was pointing at. If we are >= the split point the push node
1482 * is now in the new node.
1484 * NOTE: If we are at the split point itself we cannot stay with the
1485 * original node because the push index will point at the right-hand
1486 * boundary, which is illegal.
1488 * NOTE: The cursor's parent or parent_index must be adjusted for
1489 * the case where a new parent (new root) was created, and the case
1490 * where the cursor is now pointing at the split node.
1492 if (cursor
->index
>= split
) {
1493 cursor
->parent_index
= parent_index
+ 1;
1494 cursor
->index
-= split
;
1495 hammer_unlock(&cursor
->node
->lock
);
1496 hammer_rel_node(cursor
->node
);
1497 cursor
->node
= new_node
; /* locked and ref'd */
1499 cursor
->parent_index
= parent_index
;
1500 hammer_unlock(&new_node
->lock
);
1501 hammer_rel_node(new_node
);
1505 * Fixup left and right bounds
1507 parent_elm
= &parent
->ondisk
->elms
[cursor
->parent_index
];
1508 cursor
->left_bound
= &parent_elm
[0].internal
.base
;
1509 cursor
->right_bound
= &parent_elm
[1].internal
.base
;
1510 KKASSERT(hammer_btree_cmp(cursor
->left_bound
,
1511 &cursor
->node
->ondisk
->elms
[0].internal
.base
) <= 0);
1512 KKASSERT(hammer_btree_cmp(cursor
->right_bound
,
1513 &cursor
->node
->ondisk
->elms
[cursor
->node
->ondisk
->count
].internal
.base
) >= 0);
1516 hammer_btree_unlock_children(&locklist
);
1517 hammer_cursor_downgrade(cursor
);
1522 * Same as the above, but splits a full leaf node.
1528 btree_split_leaf(hammer_cursor_t cursor
)
1530 hammer_node_ondisk_t ondisk
;
1531 hammer_node_t parent
;
1534 hammer_node_t new_leaf
;
1535 hammer_btree_elm_t elm
;
1536 hammer_btree_elm_t parent_elm
;
1537 hammer_base_elm_t mid_boundary
;
1542 const size_t esize
= sizeof(*elm
);
1544 if ((error
= hammer_cursor_upgrade(cursor
)) != 0)
1546 ++hammer_stats_btree_splits
;
1548 KKASSERT(hammer_btree_cmp(cursor
->left_bound
,
1549 &cursor
->node
->ondisk
->elms
[0].leaf
.base
) <= 0);
1550 KKASSERT(hammer_btree_cmp(cursor
->right_bound
,
1551 &cursor
->node
->ondisk
->elms
[cursor
->node
->ondisk
->count
-1].leaf
.base
) > 0);
1554 * Calculate the split point. If the insertion point will be on
1555 * the left-hand side adjust the split point to give the right
1556 * hand side one additional node.
1558 * Spikes are made up of two leaf elements which cannot be
1561 leaf
= cursor
->node
;
1562 ondisk
= leaf
->ondisk
;
1563 split
= (ondisk
->count
+ 1) / 2;
1564 if (cursor
->index
<= split
)
1569 elm
= &ondisk
->elms
[split
];
1571 KKASSERT(hammer_btree_cmp(cursor
->left_bound
, &elm
[-1].leaf
.base
) <= 0);
1572 KKASSERT(hammer_btree_cmp(cursor
->left_bound
, &elm
->leaf
.base
) <= 0);
1573 KKASSERT(hammer_btree_cmp(cursor
->right_bound
, &elm
->leaf
.base
) > 0);
1574 KKASSERT(hammer_btree_cmp(cursor
->right_bound
, &elm
[1].leaf
.base
) > 0);
1577 * If we are at the root of the tree, create a new root node with
1578 * 1 element and split normally. Avoid making major modifications
1579 * until we know the whole operation will work.
1581 if (ondisk
->parent
== 0) {
1582 parent
= hammer_alloc_btree(cursor
->trans
, &error
);
1585 hammer_lock_ex(&parent
->lock
);
1586 hammer_modify_node_noundo(cursor
->trans
, parent
);
1587 ondisk
= parent
->ondisk
;
1590 ondisk
->type
= HAMMER_BTREE_TYPE_INTERNAL
;
1591 ondisk
->elms
[0].base
= hmp
->root_btree_beg
;
1592 ondisk
->elms
[0].base
.btype
= leaf
->ondisk
->type
;
1593 ondisk
->elms
[0].internal
.subtree_offset
= leaf
->node_offset
;
1594 ondisk
->elms
[1].base
= hmp
->root_btree_end
;
1595 /* ondisk->elms[1].base.btype = not used */
1596 hammer_modify_node_done(parent
);
1598 parent_index
= 0; /* insertion point in parent */
1601 parent
= cursor
->parent
;
1602 parent_index
= cursor
->parent_index
;
1606 * Split leaf into new_leaf at the split point. Select a separator
1607 * value in-between the two leafs but with a bent towards the right
1608 * leaf since comparisons use an 'elm >= separator' inequality.
1617 new_leaf
= hammer_alloc_btree(cursor
->trans
, &error
);
1618 if (new_leaf
== NULL
) {
1620 hammer_unlock(&parent
->lock
);
1621 hammer_delete_node(cursor
->trans
, parent
);
1622 hammer_rel_node(parent
);
1626 hammer_lock_ex(&new_leaf
->lock
);
1629 * Create the new node and copy the leaf elements from the split
1630 * point on to the new node.
1632 hammer_modify_node_all(cursor
->trans
, leaf
);
1633 hammer_modify_node_noundo(cursor
->trans
, new_leaf
);
1634 ondisk
= leaf
->ondisk
;
1635 elm
= &ondisk
->elms
[split
];
1636 bcopy(elm
, &new_leaf
->ondisk
->elms
[0], (ondisk
->count
- split
) * esize
);
1637 new_leaf
->ondisk
->count
= ondisk
->count
- split
;
1638 new_leaf
->ondisk
->parent
= parent
->node_offset
;
1639 new_leaf
->ondisk
->type
= HAMMER_BTREE_TYPE_LEAF
;
1640 KKASSERT(ondisk
->type
== new_leaf
->ondisk
->type
);
1641 hammer_modify_node_done(new_leaf
);
1644 * Cleanup the original node. Because this is a leaf node and
1645 * leaf nodes do not have a right-hand boundary, there
1646 * aren't any special edge cases to clean up. We just fixup the
1649 ondisk
->count
= split
;
1652 * Insert the separator into the parent, fixup the parent's
1653 * reference to the original node, and reference the new node.
1654 * The separator is P.
1656 * Remember that base.count does not include the right-hand boundary.
1657 * We are copying parent_index+1 to parent_index+2, not +0 to +1.
1659 hammer_modify_node_all(cursor
->trans
, parent
);
1660 ondisk
= parent
->ondisk
;
1661 KKASSERT(split
!= 0);
1662 KKASSERT(ondisk
->count
!= HAMMER_BTREE_INT_ELMS
);
1663 parent_elm
= &ondisk
->elms
[parent_index
+1];
1664 bcopy(parent_elm
, parent_elm
+ 1,
1665 (ondisk
->count
- parent_index
) * esize
);
1667 hammer_make_separator(&elm
[-1].base
, &elm
[0].base
, &parent_elm
->base
);
1668 parent_elm
->internal
.base
.btype
= new_leaf
->ondisk
->type
;
1669 parent_elm
->internal
.subtree_offset
= new_leaf
->node_offset
;
1670 mid_boundary
= &parent_elm
->base
;
1672 hammer_modify_node_done(parent
);
1675 * The filesystem's root B-Tree pointer may have to be updated.
1678 hammer_volume_t volume
;
1680 volume
= hammer_get_root_volume(hmp
, &error
);
1681 KKASSERT(error
== 0);
1683 hammer_modify_volume_field(cursor
->trans
, volume
,
1685 volume
->ondisk
->vol0_btree_root
= parent
->node_offset
;
1686 hammer_modify_volume_done(volume
);
1687 leaf
->ondisk
->parent
= parent
->node_offset
;
1688 if (cursor
->parent
) {
1689 hammer_unlock(&cursor
->parent
->lock
);
1690 hammer_rel_node(cursor
->parent
);
1692 cursor
->parent
= parent
; /* lock'd and ref'd */
1693 hammer_rel_volume(volume
, 0);
1695 hammer_modify_node_done(leaf
);
1698 * Ok, now adjust the cursor depending on which element the original
1699 * index was pointing at. If we are >= the split point the push node
1700 * is now in the new node.
1702 * NOTE: If we are at the split point itself we need to select the
1703 * old or new node based on where key_beg's insertion point will be.
1704 * If we pick the wrong side the inserted element will wind up in
1705 * the wrong leaf node and outside that node's bounds.
1707 if (cursor
->index
> split
||
1708 (cursor
->index
== split
&&
1709 hammer_btree_cmp(&cursor
->key_beg
, mid_boundary
) >= 0)) {
1710 cursor
->parent_index
= parent_index
+ 1;
1711 cursor
->index
-= split
;
1712 hammer_unlock(&cursor
->node
->lock
);
1713 hammer_rel_node(cursor
->node
);
1714 cursor
->node
= new_leaf
;
1716 cursor
->parent_index
= parent_index
;
1717 hammer_unlock(&new_leaf
->lock
);
1718 hammer_rel_node(new_leaf
);
1722 * Fixup left and right bounds
1724 parent_elm
= &parent
->ondisk
->elms
[cursor
->parent_index
];
1725 cursor
->left_bound
= &parent_elm
[0].internal
.base
;
1726 cursor
->right_bound
= &parent_elm
[1].internal
.base
;
1729 * Assert that the bounds are correct.
1731 KKASSERT(hammer_btree_cmp(cursor
->left_bound
,
1732 &cursor
->node
->ondisk
->elms
[0].leaf
.base
) <= 0);
1733 KKASSERT(hammer_btree_cmp(cursor
->right_bound
,
1734 &cursor
->node
->ondisk
->elms
[cursor
->node
->ondisk
->count
-1].leaf
.base
) > 0);
1735 KKASSERT(hammer_btree_cmp(cursor
->left_bound
, &cursor
->key_beg
) <= 0);
1736 KKASSERT(hammer_btree_cmp(cursor
->right_bound
, &cursor
->key_beg
) > 0);
1739 hammer_cursor_downgrade(cursor
);
1744 * Recursively correct the right-hand boundary's create_tid to (tid) as
1745 * long as the rest of the key matches. We have to recurse upward in
1746 * the tree as well as down the left side of each parent's right node.
1748 * Return EDEADLK if we were only partially successful, forcing the caller
1749 * to try again. The original cursor is not modified. This routine can
1750 * also fail with EDEADLK if it is forced to throw away a portion of its
1753 * The caller must pass a downgraded cursor to us (otherwise we can't dup it).
1756 TAILQ_ENTRY(hammer_rhb
) entry
;
1761 TAILQ_HEAD(hammer_rhb_list
, hammer_rhb
);
1764 hammer_btree_correct_rhb(hammer_cursor_t cursor
, hammer_tid_t tid
)
1766 struct hammer_rhb_list rhb_list
;
1767 hammer_base_elm_t elm
;
1768 hammer_node_t orig_node
;
1769 struct hammer_rhb
*rhb
;
1773 TAILQ_INIT(&rhb_list
);
1776 * Save our position so we can restore it on return. This also
1777 * gives us a stable 'elm'.
1779 orig_node
= cursor
->node
;
1780 hammer_ref_node(orig_node
);
1781 hammer_lock_sh(&orig_node
->lock
);
1782 orig_index
= cursor
->index
;
1783 elm
= &orig_node
->ondisk
->elms
[orig_index
].base
;
1786 * Now build a list of parents going up, allocating a rhb
1787 * structure for each one.
1789 while (cursor
->parent
) {
1791 * Stop if we no longer have any right-bounds to fix up
1793 if (elm
->obj_id
!= cursor
->right_bound
->obj_id
||
1794 elm
->rec_type
!= cursor
->right_bound
->rec_type
||
1795 elm
->key
!= cursor
->right_bound
->key
) {
1800 * Stop if the right-hand bound's create_tid does not
1801 * need to be corrected.
1803 if (cursor
->right_bound
->create_tid
>= tid
)
1806 rhb
= kmalloc(sizeof(*rhb
), M_HAMMER
, M_WAITOK
|M_ZERO
);
1807 rhb
->node
= cursor
->parent
;
1808 rhb
->index
= cursor
->parent_index
;
1809 hammer_ref_node(rhb
->node
);
1810 hammer_lock_sh(&rhb
->node
->lock
);
1811 TAILQ_INSERT_HEAD(&rhb_list
, rhb
, entry
);
1813 hammer_cursor_up(cursor
);
1817 * now safely adjust the right hand bound for each rhb. This may
1818 * also require taking the right side of the tree and iterating down
1822 while (error
== 0 && (rhb
= TAILQ_FIRST(&rhb_list
)) != NULL
) {
1823 error
= hammer_cursor_seek(cursor
, rhb
->node
, rhb
->index
);
1826 TAILQ_REMOVE(&rhb_list
, rhb
, entry
);
1827 hammer_unlock(&rhb
->node
->lock
);
1828 hammer_rel_node(rhb
->node
);
1829 kfree(rhb
, M_HAMMER
);
1831 switch (cursor
->node
->ondisk
->type
) {
1832 case HAMMER_BTREE_TYPE_INTERNAL
:
1834 * Right-boundary for parent at internal node
1835 * is one element to the right of the element whos
1836 * right boundary needs adjusting. We must then
1837 * traverse down the left side correcting any left
1838 * bounds (which may now be too far to the left).
1841 error
= hammer_btree_correct_lhb(cursor
, tid
);
1844 panic("hammer_btree_correct_rhb(): Bad node type");
1853 while ((rhb
= TAILQ_FIRST(&rhb_list
)) != NULL
) {
1854 TAILQ_REMOVE(&rhb_list
, rhb
, entry
);
1855 hammer_unlock(&rhb
->node
->lock
);
1856 hammer_rel_node(rhb
->node
);
1857 kfree(rhb
, M_HAMMER
);
1859 error
= hammer_cursor_seek(cursor
, orig_node
, orig_index
);
1860 hammer_unlock(&orig_node
->lock
);
1861 hammer_rel_node(orig_node
);
1866 * Similar to rhb (in fact, rhb calls lhb), but corrects the left hand
1867 * bound going downward starting at the current cursor position.
1869 * This function does not restore the cursor after use.
1872 hammer_btree_correct_lhb(hammer_cursor_t cursor
, hammer_tid_t tid
)
1874 struct hammer_rhb_list rhb_list
;
1875 hammer_base_elm_t elm
;
1876 hammer_base_elm_t cmp
;
1877 struct hammer_rhb
*rhb
;
1880 TAILQ_INIT(&rhb_list
);
1882 cmp
= &cursor
->node
->ondisk
->elms
[cursor
->index
].base
;
1885 * Record the node and traverse down the left-hand side for all
1886 * matching records needing a boundary correction.
1890 rhb
= kmalloc(sizeof(*rhb
), M_HAMMER
, M_WAITOK
|M_ZERO
);
1891 rhb
->node
= cursor
->node
;
1892 rhb
->index
= cursor
->index
;
1893 hammer_ref_node(rhb
->node
);
1894 hammer_lock_sh(&rhb
->node
->lock
);
1895 TAILQ_INSERT_HEAD(&rhb_list
, rhb
, entry
);
1897 if (cursor
->node
->ondisk
->type
== HAMMER_BTREE_TYPE_INTERNAL
) {
1899 * Nothing to traverse down if we are at the right
1900 * boundary of an internal node.
1902 if (cursor
->index
== cursor
->node
->ondisk
->count
)
1905 elm
= &cursor
->node
->ondisk
->elms
[cursor
->index
].base
;
1906 if (elm
->btype
== HAMMER_BTREE_TYPE_RECORD
)
1908 panic("Illegal leaf record type %02x", elm
->btype
);
1910 error
= hammer_cursor_down(cursor
);
1914 elm
= &cursor
->node
->ondisk
->elms
[cursor
->index
].base
;
1915 if (elm
->obj_id
!= cmp
->obj_id
||
1916 elm
->rec_type
!= cmp
->rec_type
||
1917 elm
->key
!= cmp
->key
) {
1920 if (elm
->create_tid
>= tid
)
1926 * Now we can safely adjust the left-hand boundary from the bottom-up.
1927 * The last element we remove from the list is the caller's right hand
1928 * boundary, which must also be adjusted.
1930 while (error
== 0 && (rhb
= TAILQ_FIRST(&rhb_list
)) != NULL
) {
1931 error
= hammer_cursor_seek(cursor
, rhb
->node
, rhb
->index
);
1934 TAILQ_REMOVE(&rhb_list
, rhb
, entry
);
1935 hammer_unlock(&rhb
->node
->lock
);
1936 hammer_rel_node(rhb
->node
);
1937 kfree(rhb
, M_HAMMER
);
1939 elm
= &cursor
->node
->ondisk
->elms
[cursor
->index
].base
;
1940 if (cursor
->node
->ondisk
->type
== HAMMER_BTREE_TYPE_INTERNAL
) {
1941 hammer_modify_node(cursor
->trans
, cursor
->node
,
1943 sizeof(elm
->create_tid
));
1944 elm
->create_tid
= tid
;
1945 hammer_modify_node_done(cursor
->node
);
1947 panic("hammer_btree_correct_lhb(): Bad element type");
1954 while ((rhb
= TAILQ_FIRST(&rhb_list
)) != NULL
) {
1955 TAILQ_REMOVE(&rhb_list
, rhb
, entry
);
1956 hammer_unlock(&rhb
->node
->lock
);
1957 hammer_rel_node(rhb
->node
);
1958 kfree(rhb
, M_HAMMER
);
1964 * Attempt to remove the locked, empty or want-to-be-empty B-Tree node at
1965 * (cursor->node). Returns 0 on success, EDEADLK if we could not complete
1966 * the operation due to a deadlock, or some other error.
1968 * This routine is always called with an empty, locked leaf but may recurse
1969 * into want-to-be-empty parents as part of its operation.
1971 * On return the cursor may end up pointing to an internal node, suitable
1972 * for further iteration but not for an immediate insertion or deletion.
1975 btree_remove(hammer_cursor_t cursor
)
1977 hammer_node_ondisk_t ondisk
;
1978 hammer_btree_elm_t elm
;
1980 hammer_node_t parent
;
1981 const int esize
= sizeof(*elm
);
1984 node
= cursor
->node
;
1987 * When deleting the root of the filesystem convert it to
1988 * an empty leaf node. Internal nodes cannot be empty.
1990 if (node
->ondisk
->parent
== 0) {
1991 KKASSERT(cursor
->parent
== NULL
);
1992 hammer_modify_node_all(cursor
->trans
, node
);
1993 ondisk
= node
->ondisk
;
1994 ondisk
->type
= HAMMER_BTREE_TYPE_LEAF
;
1996 hammer_modify_node_done(node
);
2002 * Attempt to remove the parent's reference to the child. If the
2003 * parent would become empty we have to recurse. If we fail we
2004 * leave the parent pointing to an empty leaf node.
2006 parent
= cursor
->parent
;
2008 if (parent
->ondisk
->count
== 1) {
2010 * This special cursor_up_locked() call leaves the original
2011 * node exclusively locked and referenced, leaves the
2012 * original parent locked (as the new node), and locks the
2013 * new parent. It can return EDEADLK.
2015 error
= hammer_cursor_up_locked(cursor
);
2017 error
= btree_remove(cursor
);
2019 hammer_modify_node_all(cursor
->trans
, node
);
2020 ondisk
= node
->ondisk
;
2021 ondisk
->type
= HAMMER_BTREE_TYPE_DELETED
;
2023 hammer_modify_node_done(node
);
2024 hammer_flush_node(node
);
2025 hammer_delete_node(cursor
->trans
, node
);
2027 kprintf("Warning: BTREE_REMOVE: Defering "
2028 "parent removal1 @ %016llx, skipping\n",
2031 hammer_unlock(&node
->lock
);
2032 hammer_rel_node(node
);
2034 kprintf("Warning: BTREE_REMOVE: Defering parent "
2035 "removal2 @ %016llx, skipping\n",
2039 KKASSERT(parent
->ondisk
->count
> 1);
2042 * Delete the subtree reference in the parent
2044 hammer_modify_node_all(cursor
->trans
, parent
);
2045 ondisk
= parent
->ondisk
;
2046 KKASSERT(ondisk
->type
== HAMMER_BTREE_TYPE_INTERNAL
);
2047 elm
= &ondisk
->elms
[cursor
->parent_index
];
2048 KKASSERT(elm
->internal
.subtree_offset
== node
->node_offset
);
2049 KKASSERT(ondisk
->count
> 0);
2050 bcopy(&elm
[1], &elm
[0],
2051 (ondisk
->count
- cursor
->parent_index
) * esize
);
2053 hammer_modify_node_done(parent
);
2054 hammer_flush_node(node
);
2055 hammer_delete_node(cursor
->trans
, node
);
2058 * cursor->node is invalid, cursor up to make the cursor
2061 error
= hammer_cursor_up(cursor
);
2067 * The element (elm) has been moved to a new internal node (node).
2069 * If the element represents a pointer to an internal node that node's
2070 * parent must be adjusted to the element's new location.
2072 * XXX deadlock potential here with our exclusive locks
2075 btree_set_parent(hammer_transaction_t trans
, hammer_node_t node
,
2076 hammer_btree_elm_t elm
)
2078 hammer_node_t child
;
2083 switch(elm
->base
.btype
) {
2084 case HAMMER_BTREE_TYPE_INTERNAL
:
2085 case HAMMER_BTREE_TYPE_LEAF
:
2086 child
= hammer_get_node(node
->hmp
, elm
->internal
.subtree_offset
,
2089 hammer_modify_node_field(trans
, child
, parent
);
2090 child
->ondisk
->parent
= node
->node_offset
;
2091 hammer_modify_node_done(child
);
2092 hammer_rel_node(child
);
2102 * Exclusively lock all the children of node. This is used by the split
2103 * code to prevent anyone from accessing the children of a cursor node
2104 * while we fix-up its parent offset.
2106 * If we don't lock the children we can really mess up cursors which block
2107 * trying to cursor-up into our node.
2109 * On failure EDEADLK (or some other error) is returned. If a deadlock
2110 * error is returned the cursor is adjusted to block on termination.
2113 hammer_btree_lock_children(hammer_cursor_t cursor
,
2114 struct hammer_node_locklist
**locklistp
)
2117 hammer_node_locklist_t item
;
2118 hammer_node_ondisk_t ondisk
;
2119 hammer_btree_elm_t elm
;
2120 hammer_node_t child
;
2124 node
= cursor
->node
;
2125 ondisk
= node
->ondisk
;
2129 * We really do not want to block on I/O with exclusive locks held,
2130 * pre-get the children before trying to lock the mess.
2132 for (i
= 0; i
< ondisk
->count
; ++i
) {
2133 ++hammer_stats_btree_elements
;
2134 elm
= &ondisk
->elms
[i
];
2135 if (elm
->base
.btype
!= HAMMER_BTREE_TYPE_LEAF
&&
2136 elm
->base
.btype
!= HAMMER_BTREE_TYPE_INTERNAL
) {
2139 child
= hammer_get_node(node
->hmp
,
2140 elm
->internal
.subtree_offset
,
2143 hammer_rel_node(child
);
2149 for (i
= 0; error
== 0 && i
< ondisk
->count
; ++i
) {
2150 ++hammer_stats_btree_elements
;
2151 elm
= &ondisk
->elms
[i
];
2153 switch(elm
->base
.btype
) {
2154 case HAMMER_BTREE_TYPE_INTERNAL
:
2155 case HAMMER_BTREE_TYPE_LEAF
:
2156 KKASSERT(elm
->internal
.subtree_offset
!= 0);
2157 child
= hammer_get_node(node
->hmp
,
2158 elm
->internal
.subtree_offset
,
2166 if (hammer_lock_ex_try(&child
->lock
) != 0) {
2167 if (cursor
->deadlk_node
== NULL
) {
2168 cursor
->deadlk_node
= child
;
2169 hammer_ref_node(cursor
->deadlk_node
);
2172 hammer_rel_node(child
);
2174 item
= kmalloc(sizeof(*item
),
2175 M_HAMMER
, M_WAITOK
);
2176 item
->next
= *locklistp
;
2183 hammer_btree_unlock_children(locklistp
);
2189 * Release previously obtained node locks.
2192 hammer_btree_unlock_children(struct hammer_node_locklist
**locklistp
)
2194 hammer_node_locklist_t item
;
2196 while ((item
= *locklistp
) != NULL
) {
2197 *locklistp
= item
->next
;
2198 hammer_unlock(&item
->node
->lock
);
2199 hammer_rel_node(item
->node
);
2200 kfree(item
, M_HAMMER
);
2204 /************************************************************************
2205 * MISCELLANIOUS SUPPORT *
2206 ************************************************************************/
2209 * Compare two B-Tree elements, return -N, 0, or +N (e.g. similar to strcmp).
2211 * Note that for this particular function a return value of -1, 0, or +1
2212 * can denote a match if create_tid is otherwise discounted. A create_tid
2213 * of zero is considered to be 'infinity' in comparisons.
2215 * See also hammer_rec_rb_compare() and hammer_rec_cmp() in hammer_object.c.
2218 hammer_btree_cmp(hammer_base_elm_t key1
, hammer_base_elm_t key2
)
2220 if (key1
->localization
< key2
->localization
)
2222 if (key1
->localization
> key2
->localization
)
2225 if (key1
->obj_id
< key2
->obj_id
)
2227 if (key1
->obj_id
> key2
->obj_id
)
2230 if (key1
->rec_type
< key2
->rec_type
)
2232 if (key1
->rec_type
> key2
->rec_type
)
2235 if (key1
->key
< key2
->key
)
2237 if (key1
->key
> key2
->key
)
2241 * A create_tid of zero indicates a record which is undeletable
2242 * and must be considered to have a value of positive infinity.
2244 if (key1
->create_tid
== 0) {
2245 if (key2
->create_tid
== 0)
2249 if (key2
->create_tid
== 0)
2251 if (key1
->create_tid
< key2
->create_tid
)
2253 if (key1
->create_tid
> key2
->create_tid
)
2259 * Test a timestamp against an element to determine whether the
2260 * element is visible. A timestamp of 0 means 'infinity'.
2263 hammer_btree_chkts(hammer_tid_t asof
, hammer_base_elm_t base
)
2266 if (base
->delete_tid
)
2270 if (asof
< base
->create_tid
)
2272 if (base
->delete_tid
&& asof
>= base
->delete_tid
)
2278 * Create a separator half way inbetween key1 and key2. For fields just
2279 * one unit apart, the separator will match key2. key1 is on the left-hand
2280 * side and key2 is on the right-hand side.
2282 * key2 must be >= the separator. It is ok for the separator to match key2.
2284 * NOTE: Even if key1 does not match key2, the separator may wind up matching
2287 * NOTE: It might be beneficial to just scrap this whole mess and just
2288 * set the separator to key2.
2290 #define MAKE_SEPARATOR(key1, key2, dest, field) \
2291 dest->field = key1->field + ((key2->field - key1->field + 1) >> 1);
2294 hammer_make_separator(hammer_base_elm_t key1
, hammer_base_elm_t key2
,
2295 hammer_base_elm_t dest
)
2297 bzero(dest
, sizeof(*dest
));
2299 dest
->rec_type
= key2
->rec_type
;
2300 dest
->key
= key2
->key
;
2301 dest
->obj_id
= key2
->obj_id
;
2302 dest
->create_tid
= key2
->create_tid
;
2304 MAKE_SEPARATOR(key1
, key2
, dest
, localization
);
2305 if (key1
->localization
== key2
->localization
) {
2306 MAKE_SEPARATOR(key1
, key2
, dest
, obj_id
);
2307 if (key1
->obj_id
== key2
->obj_id
) {
2308 MAKE_SEPARATOR(key1
, key2
, dest
, rec_type
);
2309 if (key1
->rec_type
== key2
->rec_type
) {
2310 MAKE_SEPARATOR(key1
, key2
, dest
, key
);
2312 * Don't bother creating a separator for
2313 * create_tid, which also conveniently avoids
2314 * having to handle the create_tid == 0
2315 * (infinity) case. Just leave create_tid
2318 * Worst case, dest matches key2 exactly,
2319 * which is acceptable.
2326 #undef MAKE_SEPARATOR
2329 * Return whether a generic internal or leaf node is full
2332 btree_node_is_full(hammer_node_ondisk_t node
)
2334 switch(node
->type
) {
2335 case HAMMER_BTREE_TYPE_INTERNAL
:
2336 if (node
->count
== HAMMER_BTREE_INT_ELMS
)
2339 case HAMMER_BTREE_TYPE_LEAF
:
2340 if (node
->count
== HAMMER_BTREE_LEAF_ELMS
)
2344 panic("illegal btree subtype");
2351 btree_max_elements(u_int8_t type
)
2353 if (type
== HAMMER_BTREE_TYPE_LEAF
)
2354 return(HAMMER_BTREE_LEAF_ELMS
);
2355 if (type
== HAMMER_BTREE_TYPE_INTERNAL
)
2356 return(HAMMER_BTREE_INT_ELMS
);
2357 panic("btree_max_elements: bad type %d\n", type
);
2362 hammer_print_btree_node(hammer_node_ondisk_t ondisk
)
2364 hammer_btree_elm_t elm
;
2367 kprintf("node %p count=%d parent=%016llx type=%c\n",
2368 ondisk
, ondisk
->count
, ondisk
->parent
, ondisk
->type
);
2371 * Dump both boundary elements if an internal node
2373 if (ondisk
->type
== HAMMER_BTREE_TYPE_INTERNAL
) {
2374 for (i
= 0; i
<= ondisk
->count
; ++i
) {
2375 elm
= &ondisk
->elms
[i
];
2376 hammer_print_btree_elm(elm
, ondisk
->type
, i
);
2379 for (i
= 0; i
< ondisk
->count
; ++i
) {
2380 elm
= &ondisk
->elms
[i
];
2381 hammer_print_btree_elm(elm
, ondisk
->type
, i
);
2387 hammer_print_btree_elm(hammer_btree_elm_t elm
, u_int8_t type
, int i
)
2390 kprintf("\tobj_id = %016llx\n", elm
->base
.obj_id
);
2391 kprintf("\tkey = %016llx\n", elm
->base
.key
);
2392 kprintf("\tcreate_tid = %016llx\n", elm
->base
.create_tid
);
2393 kprintf("\tdelete_tid = %016llx\n", elm
->base
.delete_tid
);
2394 kprintf("\trec_type = %04x\n", elm
->base
.rec_type
);
2395 kprintf("\tobj_type = %02x\n", elm
->base
.obj_type
);
2396 kprintf("\tbtype = %02x (%c)\n",
2398 (elm
->base
.btype
? elm
->base
.btype
: '?'));
2399 kprintf("\tlocalization = %02x\n", elm
->base
.localization
);
2402 case HAMMER_BTREE_TYPE_INTERNAL
:
2403 kprintf("\tsubtree_off = %016llx\n",
2404 elm
->internal
.subtree_offset
);
2406 case HAMMER_BTREE_TYPE_RECORD
:
2407 kprintf("\tdata_offset = %016llx\n", elm
->leaf
.data_offset
);
2408 kprintf("\tdata_len = %08x\n", elm
->leaf
.data_len
);
2409 kprintf("\tdata_crc = %08x\n", elm
->leaf
.data_crc
);