2 * Copyright (C) 2011 Red Hat, Inc.
4 * This file is released under the GPL.
7 #include "dm-btree-internal.h"
8 #include "dm-space-map.h"
9 #include "dm-transaction-manager.h"
11 #include <linux/export.h>
12 #include <linux/device-mapper.h>
14 #define DM_MSG_PREFIX "btree"
16 /*----------------------------------------------------------------
18 *--------------------------------------------------------------*/
19 static void memcpy_disk(void *dest, const void *src, size_t len)
20 __dm_written_to_disk(src)
22 memcpy(dest, src, len);
23 __dm_unbless_for_disk(src);
26 static void array_insert(void *base, size_t elt_size, unsigned nr_elts,
27 unsigned index, void *elt)
28 __dm_written_to_disk(elt)
31 memmove(base + (elt_size * (index + 1)),
32 base + (elt_size * index),
33 (nr_elts - index) * elt_size);
35 memcpy_disk(base + (elt_size * index), elt, elt_size);
38 /*----------------------------------------------------------------*/
40 /* makes the assumption that no two keys are the same. */
41 static int bsearch(struct btree_node *n, uint64_t key, int want_hi)
43 int lo = -1, hi = le32_to_cpu(n->header.nr_entries);
46 int mid = lo + ((hi - lo) / 2);
47 uint64_t mid_key = le64_to_cpu(n->keys[mid]);
58 return want_hi ? hi : lo;
61 int lower_bound(struct btree_node *n, uint64_t key)
63 return bsearch(n, key, 0);
66 void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,
67 struct dm_btree_value_type *vt)
70 uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
72 if (le32_to_cpu(n->header.flags) & INTERNAL_NODE)
73 for (i = 0; i < nr_entries; i++)
74 dm_tm_inc(tm, value64(n, i));
76 for (i = 0; i < nr_entries; i++)
77 vt->inc(vt->context, value_ptr(n, i));
80 static int insert_at(size_t value_size, struct btree_node *node, unsigned index,
81 uint64_t key, void *value)
82 __dm_written_to_disk(value)
84 uint32_t nr_entries = le32_to_cpu(node->header.nr_entries);
85 __le64 key_le = cpu_to_le64(key);
87 if (index > nr_entries ||
88 index >= le32_to_cpu(node->header.max_entries)) {
89 DMERR("too many entries in btree node for insert");
90 __dm_unbless_for_disk(value);
94 __dm_bless_for_disk(&key_le);
96 array_insert(node->keys, sizeof(*node->keys), nr_entries, index, &key_le);
97 array_insert(value_base(node), value_size, nr_entries, index, value);
98 node->header.nr_entries = cpu_to_le32(nr_entries + 1);
103 /*----------------------------------------------------------------*/
106 * We want 3n entries (for some n). This works more nicely for repeated
107 * insert remove loops than (2n + 1).
109 static uint32_t calc_max_entries(size_t value_size, size_t block_size)
112 size_t elt_size = sizeof(uint64_t) + value_size; /* key + value */
114 block_size -= sizeof(struct node_header);
115 total = block_size / elt_size;
116 n = total / 3; /* rounds down */
121 int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root)
125 struct btree_node *n;
127 uint32_t max_entries;
129 r = new_block(info, &b);
133 block_size = dm_bm_block_size(dm_tm_get_bm(info->tm));
134 max_entries = calc_max_entries(info->value_type.size, block_size);
136 n = dm_block_data(b);
137 memset(n, 0, block_size);
138 n->header.flags = cpu_to_le32(LEAF_NODE);
139 n->header.nr_entries = cpu_to_le32(0);
140 n->header.max_entries = cpu_to_le32(max_entries);
141 n->header.value_size = cpu_to_le32(info->value_type.size);
143 *root = dm_block_location(b);
144 return unlock_block(info, b);
146 EXPORT_SYMBOL_GPL(dm_btree_empty);
148 /*----------------------------------------------------------------*/
151 * Deletion uses a recursive algorithm, since we have limited stack space
152 * we explicitly manage our own stack on the heap.
154 #define MAX_SPINE_DEPTH 64
157 struct btree_node *n;
159 unsigned nr_children;
160 unsigned current_child;
164 struct dm_transaction_manager *tm;
166 struct frame spine[MAX_SPINE_DEPTH];
169 static int top_frame(struct del_stack *s, struct frame **f)
172 DMERR("btree deletion stack empty");
176 *f = s->spine + s->top;
181 static int unprocessed_frames(struct del_stack *s)
186 static int push_frame(struct del_stack *s, dm_block_t b, unsigned level)
191 if (s->top >= MAX_SPINE_DEPTH - 1) {
192 DMERR("btree deletion stack out of memory");
196 r = dm_tm_ref(s->tm, b, &ref_count);
202 * This is a shared node, so we can just decrement it's
203 * reference counter and leave the children.
208 struct frame *f = s->spine + ++s->top;
210 r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b);
216 f->n = dm_block_data(f->b);
218 f->nr_children = le32_to_cpu(f->n->header.nr_entries);
219 f->current_child = 0;
225 static void pop_frame(struct del_stack *s)
227 struct frame *f = s->spine + s->top--;
229 dm_tm_dec(s->tm, dm_block_location(f->b));
230 dm_tm_unlock(s->tm, f->b);
233 int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
238 s = kmalloc(sizeof(*s), GFP_KERNEL);
244 r = push_frame(s, root, 1);
248 while (unprocessed_frames(s)) {
253 r = top_frame(s, &f);
257 if (f->current_child >= f->nr_children) {
262 flags = le32_to_cpu(f->n->header.flags);
263 if (flags & INTERNAL_NODE) {
264 b = value64(f->n, f->current_child);
266 r = push_frame(s, b, f->level);
270 } else if (f->level != (info->levels - 1)) {
271 b = value64(f->n, f->current_child);
273 r = push_frame(s, b, f->level + 1);
278 if (info->value_type.dec) {
281 for (i = 0; i < f->nr_children; i++)
282 info->value_type.dec(info->value_type.context,
285 f->current_child = f->nr_children;
293 EXPORT_SYMBOL_GPL(dm_btree_del);
295 /*----------------------------------------------------------------*/
297 static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key,
298 int (*search_fn)(struct btree_node *, uint64_t),
299 uint64_t *result_key, void *v, size_t value_size)
302 uint32_t flags, nr_entries;
305 r = ro_step(s, block);
309 i = search_fn(ro_node(s), key);
311 flags = le32_to_cpu(ro_node(s)->header.flags);
312 nr_entries = le32_to_cpu(ro_node(s)->header.nr_entries);
313 if (i < 0 || i >= nr_entries)
316 if (flags & INTERNAL_NODE)
317 block = value64(ro_node(s), i);
319 } while (!(flags & LEAF_NODE));
321 *result_key = le64_to_cpu(ro_node(s)->keys[i]);
322 memcpy(v, value_ptr(ro_node(s), i), value_size);
327 int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
328 uint64_t *keys, void *value_le)
330 unsigned level, last_level = info->levels - 1;
333 __le64 internal_value_le;
334 struct ro_spine spine;
336 init_ro_spine(&spine, info);
337 for (level = 0; level < info->levels; level++) {
341 if (level == last_level) {
343 size = info->value_type.size;
346 value_p = &internal_value_le;
347 size = sizeof(uint64_t);
350 r = btree_lookup_raw(&spine, root, keys[level],
355 if (rkey != keys[level]) {
356 exit_ro_spine(&spine);
360 exit_ro_spine(&spine);
364 root = le64_to_cpu(internal_value_le);
366 exit_ro_spine(&spine);
370 EXPORT_SYMBOL_GPL(dm_btree_lookup);
373 * Splits a node by creating a sibling node and shifting half the nodes
374 * contents across. Assumes there is a parent node, and it has room for
396 * +---------+ +-------+
400 * Where A* is a shadow of A.
402 static int btree_split_sibling(struct shadow_spine *s, dm_block_t root,
403 unsigned parent_index, uint64_t key)
407 unsigned nr_left, nr_right;
408 struct dm_block *left, *right, *parent;
409 struct btree_node *ln, *rn, *pn;
412 left = shadow_current(s);
414 r = new_block(s->info, &right);
418 ln = dm_block_data(left);
419 rn = dm_block_data(right);
421 nr_left = le32_to_cpu(ln->header.nr_entries) / 2;
422 nr_right = le32_to_cpu(ln->header.nr_entries) - nr_left;
424 ln->header.nr_entries = cpu_to_le32(nr_left);
426 rn->header.flags = ln->header.flags;
427 rn->header.nr_entries = cpu_to_le32(nr_right);
428 rn->header.max_entries = ln->header.max_entries;
429 rn->header.value_size = ln->header.value_size;
430 memcpy(rn->keys, ln->keys + nr_left, nr_right * sizeof(rn->keys[0]));
432 size = le32_to_cpu(ln->header.flags) & INTERNAL_NODE ?
433 sizeof(uint64_t) : s->info->value_type.size;
434 memcpy(value_ptr(rn, 0), value_ptr(ln, nr_left),
438 * Patch up the parent
440 parent = shadow_parent(s);
442 pn = dm_block_data(parent);
443 location = cpu_to_le64(dm_block_location(left));
444 __dm_bless_for_disk(&location);
445 memcpy_disk(value_ptr(pn, parent_index),
446 &location, sizeof(__le64));
448 location = cpu_to_le64(dm_block_location(right));
449 __dm_bless_for_disk(&location);
451 r = insert_at(sizeof(__le64), pn, parent_index + 1,
452 le64_to_cpu(rn->keys[0]), &location);
456 if (key < le64_to_cpu(rn->keys[0])) {
457 unlock_block(s->info, right);
460 unlock_block(s->info, left);
468 * Splits a node by creating two new children beneath the given node.
484 * +-------+ +-------+
485 * | B +++ | | C +++ |
486 * +-------+ +-------+
488 static int btree_split_beneath(struct shadow_spine *s, uint64_t key)
492 unsigned nr_left, nr_right;
493 struct dm_block *left, *right, *new_parent;
494 struct btree_node *pn, *ln, *rn;
497 new_parent = shadow_current(s);
499 r = new_block(s->info, &left);
503 r = new_block(s->info, &right);
505 /* FIXME: put left */
509 pn = dm_block_data(new_parent);
510 ln = dm_block_data(left);
511 rn = dm_block_data(right);
513 nr_left = le32_to_cpu(pn->header.nr_entries) / 2;
514 nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left;
516 ln->header.flags = pn->header.flags;
517 ln->header.nr_entries = cpu_to_le32(nr_left);
518 ln->header.max_entries = pn->header.max_entries;
519 ln->header.value_size = pn->header.value_size;
521 rn->header.flags = pn->header.flags;
522 rn->header.nr_entries = cpu_to_le32(nr_right);
523 rn->header.max_entries = pn->header.max_entries;
524 rn->header.value_size = pn->header.value_size;
526 memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0]));
527 memcpy(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0]));
529 size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ?
530 sizeof(__le64) : s->info->value_type.size;
531 memcpy(value_ptr(ln, 0), value_ptr(pn, 0), nr_left * size);
532 memcpy(value_ptr(rn, 0), value_ptr(pn, nr_left),
535 /* new_parent should just point to l and r now */
536 pn->header.flags = cpu_to_le32(INTERNAL_NODE);
537 pn->header.nr_entries = cpu_to_le32(2);
538 pn->header.max_entries = cpu_to_le32(
539 calc_max_entries(sizeof(__le64),
541 dm_tm_get_bm(s->info->tm))));
542 pn->header.value_size = cpu_to_le32(sizeof(__le64));
544 val = cpu_to_le64(dm_block_location(left));
545 __dm_bless_for_disk(&val);
546 pn->keys[0] = ln->keys[0];
547 memcpy_disk(value_ptr(pn, 0), &val, sizeof(__le64));
549 val = cpu_to_le64(dm_block_location(right));
550 __dm_bless_for_disk(&val);
551 pn->keys[1] = rn->keys[0];
552 memcpy_disk(value_ptr(pn, 1), &val, sizeof(__le64));
555 * rejig the spine. This is ugly, since it knows too
556 * much about the spine
558 if (s->nodes[0] != new_parent) {
559 unlock_block(s->info, s->nodes[0]);
560 s->nodes[0] = new_parent;
562 if (key < le64_to_cpu(rn->keys[0])) {
563 unlock_block(s->info, right);
566 unlock_block(s->info, left);
574 static int btree_insert_raw(struct shadow_spine *s, dm_block_t root,
575 struct dm_btree_value_type *vt,
576 uint64_t key, unsigned *index)
578 int r, i = *index, top = 1;
579 struct btree_node *node;
582 r = shadow_step(s, root, vt);
586 node = dm_block_data(shadow_current(s));
589 * We have to patch up the parent node, ugly, but I don't
590 * see a way to do this automatically as part of the spine
593 if (shadow_has_parent(s) && i >= 0) { /* FIXME: second clause unness. */
594 __le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));
596 __dm_bless_for_disk(&location);
597 memcpy_disk(value_ptr(dm_block_data(shadow_parent(s)), i),
598 &location, sizeof(__le64));
601 node = dm_block_data(shadow_current(s));
603 if (node->header.nr_entries == node->header.max_entries) {
605 r = btree_split_beneath(s, key);
607 r = btree_split_sibling(s, root, i, key);
613 node = dm_block_data(shadow_current(s));
615 i = lower_bound(node, key);
617 if (le32_to_cpu(node->header.flags) & LEAF_NODE)
621 /* change the bounds on the lowest key */
622 node->keys[0] = cpu_to_le64(key);
626 root = value64(node, i);
630 if (i < 0 || le64_to_cpu(node->keys[i]) != key)
637 static int insert(struct dm_btree_info *info, dm_block_t root,
638 uint64_t *keys, void *value, dm_block_t *new_root,
640 __dm_written_to_disk(value)
643 unsigned level, index = -1, last_level = info->levels - 1;
644 dm_block_t block = root;
645 struct shadow_spine spine;
646 struct btree_node *n;
647 struct dm_btree_value_type le64_type;
649 le64_type.context = NULL;
650 le64_type.size = sizeof(__le64);
651 le64_type.inc = NULL;
652 le64_type.dec = NULL;
653 le64_type.equal = NULL;
655 init_shadow_spine(&spine, info);
657 for (level = 0; level < (info->levels - 1); level++) {
658 r = btree_insert_raw(&spine, block, &le64_type, keys[level], &index);
662 n = dm_block_data(shadow_current(&spine));
663 need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
664 (le64_to_cpu(n->keys[index]) != keys[level]));
670 r = dm_btree_empty(info, &new_tree);
674 new_le = cpu_to_le64(new_tree);
675 __dm_bless_for_disk(&new_le);
677 r = insert_at(sizeof(uint64_t), n, index,
678 keys[level], &new_le);
683 if (level < last_level)
684 block = value64(n, index);
687 r = btree_insert_raw(&spine, block, &info->value_type,
688 keys[level], &index);
692 n = dm_block_data(shadow_current(&spine));
693 need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
694 (le64_to_cpu(n->keys[index]) != keys[level]));
700 r = insert_at(info->value_type.size, n, index,
708 if (info->value_type.dec &&
709 (!info->value_type.equal ||
710 !info->value_type.equal(
711 info->value_type.context,
714 info->value_type.dec(info->value_type.context,
715 value_ptr(n, index));
717 memcpy_disk(value_ptr(n, index),
718 value, info->value_type.size);
721 *new_root = shadow_root(&spine);
722 exit_shadow_spine(&spine);
727 __dm_unbless_for_disk(value);
729 exit_shadow_spine(&spine);
733 int dm_btree_insert(struct dm_btree_info *info, dm_block_t root,
734 uint64_t *keys, void *value, dm_block_t *new_root)
735 __dm_written_to_disk(value)
737 return insert(info, root, keys, value, new_root, NULL);
739 EXPORT_SYMBOL_GPL(dm_btree_insert);
741 int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root,
742 uint64_t *keys, void *value, dm_block_t *new_root,
744 __dm_written_to_disk(value)
746 return insert(info, root, keys, value, new_root, inserted);
748 EXPORT_SYMBOL_GPL(dm_btree_insert_notify);
750 /*----------------------------------------------------------------*/
752 static int find_highest_key(struct ro_spine *s, dm_block_t block,
753 uint64_t *result_key, dm_block_t *next_block)
759 r = ro_step(s, block);
763 flags = le32_to_cpu(ro_node(s)->header.flags);
764 i = le32_to_cpu(ro_node(s)->header.nr_entries);
770 *result_key = le64_to_cpu(ro_node(s)->keys[i]);
771 if (next_block || flags & INTERNAL_NODE)
772 block = value64(ro_node(s), i);
774 } while (flags & INTERNAL_NODE);
781 int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
782 uint64_t *result_keys)
784 int r = 0, count = 0, level;
785 struct ro_spine spine;
787 init_ro_spine(&spine, info);
788 for (level = 0; level < info->levels; level++) {
789 r = find_highest_key(&spine, root, result_keys + level,
790 level == info->levels - 1 ? NULL : &root);
800 exit_ro_spine(&spine);
802 return r ? r : count;
804 EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);