1 // SPDX-License-Identifier: GPL-2.0
3 * Code for working with individual keys, and sorted sets of keys with in a
6 * Copyright 2012 Google, Inc.
10 #include "btree_cache.h"
12 #include "eytzinger.h"
15 #include <asm/unaligned.h>
16 #include <linux/console.h>
17 #include <linux/random.h>
18 #include <linux/prefetch.h>
21 #include "alloc_types.h"
22 #include <trace/events/bcachefs.h>
24 static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *,
27 static inline unsigned __btree_node_iter_used(struct btree_node_iter *iter)
29 unsigned n = ARRAY_SIZE(iter->data);
31 while (n && __btree_node_iter_set_end(iter, n - 1))
37 struct bset_tree *bch2_bkey_to_bset(struct btree *b, struct bkey_packed *k)
39 unsigned offset = __btree_node_key_to_offset(b, k);
43 if (offset <= t->end_offset) {
44 EBUG_ON(offset < btree_bkey_first_offset(t));
52 * There are never duplicate live keys in the btree - but including keys that
53 * have been flagged as deleted (and will be cleaned up later) we _will_ see
56 * Thus the sort order is: usual key comparison first, but for keys that compare
57 * equal the deleted key(s) come first, and the (at most one) live version comes
60 * The main reason for this is insertion: to handle overwrites, we first iterate
61 * over keys that compare equal to our insert key, and then insert immediately
62 * prior to the first key greater than the key we're inserting - our insert
63 * position will be after all keys that compare equal to our insert key, which
64 * by the time we actually do the insert will all be deleted.
67 void bch2_dump_bset(struct bch_fs *c, struct btree *b,
68 struct bset *i, unsigned set)
70 struct bkey_packed *_k, *_n;
83 k = bkey_disassemble(b, _k, &uk);
85 bch2_bkey_val_to_text(&PBUF(buf), c, k);
87 bch2_bkey_to_text(&PBUF(buf), k.k);
88 printk(KERN_ERR "block %u key %5zu: %s\n", set,
89 _k->_data - i->_data, buf);
91 if (_n == vstruct_last(i))
94 n = bkey_unpack_key(b, _n);
96 if (bpos_cmp(n.p, k.k->p) < 0) {
97 printk(KERN_ERR "Key skipped backwards\n");
101 if (!bkey_deleted(k.k) &&
102 !bpos_cmp(n.p, k.k->p))
103 printk(KERN_ERR "Duplicate keys\n");
107 void bch2_dump_btree_node(struct bch_fs *c, struct btree *b)
113 bch2_dump_bset(c, b, bset(b, t), t - b->set);
117 void bch2_dump_btree_node_iter(struct btree *b,
118 struct btree_node_iter *iter)
120 struct btree_node_iter_set *set;
122 printk(KERN_ERR "btree node iter with %u/%u sets:\n",
123 __btree_node_iter_used(iter), b->nsets);
125 btree_node_iter_for_each(iter, set) {
126 struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
127 struct bset_tree *t = bch2_bkey_to_bset(b, k);
128 struct bkey uk = bkey_unpack_key(b, k);
131 bch2_bkey_to_text(&PBUF(buf), &uk);
132 printk(KERN_ERR "set %zu key %u: %s\n",
133 t - b->set, set->k, buf);
137 #ifdef CONFIG_BCACHEFS_DEBUG
139 void __bch2_verify_btree_nr_keys(struct btree *b)
142 struct bkey_packed *k;
143 struct btree_nr_keys nr = { 0 };
146 bset_tree_for_each_key(b, t, k)
147 if (!bkey_deleted(k))
148 btree_keys_account_key_add(&nr, t - b->set, k);
150 BUG_ON(memcmp(&nr, &b->nr, sizeof(nr)));
153 static void bch2_btree_node_iter_next_check(struct btree_node_iter *_iter,
156 struct btree_node_iter iter = *_iter;
157 const struct bkey_packed *k, *n;
159 k = bch2_btree_node_iter_peek_all(&iter, b);
160 __bch2_btree_node_iter_advance(&iter, b);
161 n = bch2_btree_node_iter_peek_all(&iter, b);
163 bkey_unpack_key(b, k);
166 bkey_iter_cmp(b, k, n) > 0) {
167 struct btree_node_iter_set *set;
168 struct bkey ku = bkey_unpack_key(b, k);
169 struct bkey nu = bkey_unpack_key(b, n);
170 char buf1[80], buf2[80];
172 bch2_dump_btree_node(NULL, b);
173 bch2_bkey_to_text(&PBUF(buf1), &ku);
174 bch2_bkey_to_text(&PBUF(buf2), &nu);
175 printk(KERN_ERR "out of order/overlapping:\n%s\n%s\n",
177 printk(KERN_ERR "iter was:");
179 btree_node_iter_for_each(_iter, set) {
180 struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
181 struct bset_tree *t = bch2_bkey_to_bset(b, k);
182 printk(" [%zi %zi]", t - b->set,
183 k->_data - bset(b, t)->_data);
189 void bch2_btree_node_iter_verify(struct btree_node_iter *iter,
192 struct btree_node_iter_set *set, *s2;
193 struct bkey_packed *k, *p;
196 if (bch2_btree_node_iter_end(iter))
199 /* Verify no duplicates: */
200 btree_node_iter_for_each(iter, set)
201 btree_node_iter_for_each(iter, s2)
202 BUG_ON(set != s2 && set->end == s2->end);
204 /* Verify that set->end is correct: */
205 btree_node_iter_for_each(iter, set) {
207 if (set->end == t->end_offset)
211 BUG_ON(set->k < btree_bkey_first_offset(t) ||
212 set->k >= t->end_offset);
215 /* Verify iterator is sorted: */
216 btree_node_iter_for_each(iter, set)
217 BUG_ON(set != iter->data &&
218 btree_node_iter_cmp(b, set[-1], set[0]) > 0);
220 k = bch2_btree_node_iter_peek_all(iter, b);
222 for_each_bset(b, t) {
223 if (iter->data[0].end == t->end_offset)
226 p = bch2_bkey_prev_all(b, t,
227 bch2_btree_node_iter_bset_pos(iter, b, t));
229 BUG_ON(p && bkey_iter_cmp(b, k, p) < 0);
233 void bch2_verify_insert_pos(struct btree *b, struct bkey_packed *where,
234 struct bkey_packed *insert, unsigned clobber_u64s)
236 struct bset_tree *t = bch2_bkey_to_bset(b, where);
237 struct bkey_packed *prev = bch2_bkey_prev_all(b, t, where);
238 struct bkey_packed *next = (void *) (where->_data + clobber_u64s);
241 bkey_iter_cmp(b, prev, insert) > 0);
244 bkey_iter_cmp(b, prev, insert) > 0) {
245 struct bkey k1 = bkey_unpack_key(b, prev);
246 struct bkey k2 = bkey_unpack_key(b, insert);
250 bch2_dump_btree_node(NULL, b);
251 bch2_bkey_to_text(&PBUF(buf1), &k1);
252 bch2_bkey_to_text(&PBUF(buf2), &k2);
254 panic("prev > insert:\n"
261 BUG_ON(next != btree_bkey_last(b, t) &&
262 bkey_iter_cmp(b, insert, next) > 0);
264 if (next != btree_bkey_last(b, t) &&
265 bkey_iter_cmp(b, insert, next) > 0) {
266 struct bkey k1 = bkey_unpack_key(b, insert);
267 struct bkey k2 = bkey_unpack_key(b, next);
271 bch2_dump_btree_node(NULL, b);
272 bch2_bkey_to_text(&PBUF(buf1), &k1);
273 bch2_bkey_to_text(&PBUF(buf2), &k2);
275 panic("insert > next:\n"
285 static inline void bch2_btree_node_iter_next_check(struct btree_node_iter *iter,
290 /* Auxiliary search trees */
292 #define BFLOAT_FAILED_UNPACKED U8_MAX
293 #define BFLOAT_FAILED U8_MAX
300 #define BKEY_MANTISSA_BITS 16
302 static unsigned bkey_float_byte_offset(unsigned idx)
304 return idx * sizeof(struct bkey_float);
308 struct bkey_float f[0];
316 static unsigned bset_aux_tree_buf_end(const struct bset_tree *t)
318 BUG_ON(t->aux_data_offset == U16_MAX);
320 switch (bset_aux_tree_type(t)) {
321 case BSET_NO_AUX_TREE:
322 return t->aux_data_offset;
323 case BSET_RO_AUX_TREE:
324 return t->aux_data_offset +
325 DIV_ROUND_UP(t->size * sizeof(struct bkey_float) +
326 t->size * sizeof(u8), 8);
327 case BSET_RW_AUX_TREE:
328 return t->aux_data_offset +
329 DIV_ROUND_UP(sizeof(struct rw_aux_tree) * t->size, 8);
335 static unsigned bset_aux_tree_buf_start(const struct btree *b,
336 const struct bset_tree *t)
339 ? DIV_ROUND_UP(b->unpack_fn_len, 8)
340 : bset_aux_tree_buf_end(t - 1);
343 static void *__aux_tree_base(const struct btree *b,
344 const struct bset_tree *t)
346 return b->aux_data + t->aux_data_offset * 8;
349 static struct ro_aux_tree *ro_aux_tree_base(const struct btree *b,
350 const struct bset_tree *t)
352 EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
354 return __aux_tree_base(b, t);
357 static u8 *ro_aux_tree_prev(const struct btree *b,
358 const struct bset_tree *t)
360 EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
362 return __aux_tree_base(b, t) + bkey_float_byte_offset(t->size);
365 static struct bkey_float *bkey_float(const struct btree *b,
366 const struct bset_tree *t,
369 return ro_aux_tree_base(b, t)->f + idx;
372 static void bset_aux_tree_verify(const struct btree *b)
374 #ifdef CONFIG_BCACHEFS_DEBUG
375 const struct bset_tree *t;
377 for_each_bset(b, t) {
378 if (t->aux_data_offset == U16_MAX)
381 BUG_ON(t != b->set &&
382 t[-1].aux_data_offset == U16_MAX);
384 BUG_ON(t->aux_data_offset < bset_aux_tree_buf_start(b, t));
385 BUG_ON(t->aux_data_offset > btree_aux_data_u64s(b));
386 BUG_ON(bset_aux_tree_buf_end(t) > btree_aux_data_u64s(b));
391 void bch2_btree_keys_init(struct btree *b)
396 memset(&b->nr, 0, sizeof(b->nr));
398 for (i = 0; i < MAX_BSETS; i++)
399 b->set[i].data_offset = U16_MAX;
401 bch2_bset_set_no_aux_tree(b, b->set);
404 /* Binary tree stuff for auxiliary search trees */
407 * Cacheline/offset <-> bkey pointer arithmetic:
409 * t->tree is a binary search tree in an array; each node corresponds to a key
410 * in one cacheline in t->set (BSET_CACHELINE bytes).
412 * This means we don't have to store the full index of the key that a node in
413 * the binary tree points to; eytzinger1_to_inorder() gives us the cacheline, and
414 * then bkey_float->m gives us the offset within that cacheline, in units of 8
417 * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to
420 * To construct the bfloat for an arbitrary key we need to know what the key
421 * immediately preceding it is: we have to check if the two keys differ in the
422 * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
423 * of the previous key so we can walk backwards to it from t->tree[j]'s key.
426 static inline void *bset_cacheline(const struct btree *b,
427 const struct bset_tree *t,
430 return (void *) round_down((unsigned long) btree_bkey_first(b, t),
432 cacheline * BSET_CACHELINE;
435 static struct bkey_packed *cacheline_to_bkey(const struct btree *b,
436 const struct bset_tree *t,
440 return bset_cacheline(b, t, cacheline) + offset * 8;
443 static unsigned bkey_to_cacheline(const struct btree *b,
444 const struct bset_tree *t,
445 const struct bkey_packed *k)
447 return ((void *) k - bset_cacheline(b, t, 0)) / BSET_CACHELINE;
450 static ssize_t __bkey_to_cacheline_offset(const struct btree *b,
451 const struct bset_tree *t,
453 const struct bkey_packed *k)
455 return (u64 *) k - (u64 *) bset_cacheline(b, t, cacheline);
458 static unsigned bkey_to_cacheline_offset(const struct btree *b,
459 const struct bset_tree *t,
461 const struct bkey_packed *k)
463 size_t m = __bkey_to_cacheline_offset(b, t, cacheline, k);
469 static inline struct bkey_packed *tree_to_bkey(const struct btree *b,
470 const struct bset_tree *t,
473 return cacheline_to_bkey(b, t,
474 __eytzinger1_to_inorder(j, t->size, t->extra),
475 bkey_float(b, t, j)->key_offset);
478 static struct bkey_packed *tree_to_prev_bkey(const struct btree *b,
479 const struct bset_tree *t,
482 unsigned prev_u64s = ro_aux_tree_prev(b, t)[j];
484 return (void *) (tree_to_bkey(b, t, j)->_data - prev_u64s);
487 static struct rw_aux_tree *rw_aux_tree(const struct btree *b,
488 const struct bset_tree *t)
490 EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
492 return __aux_tree_base(b, t);
496 * For the write set - the one we're currently inserting keys into - we don't
497 * maintain a full search tree, we just keep a simple lookup table in t->prev.
499 static struct bkey_packed *rw_aux_to_bkey(const struct btree *b,
503 return __btree_node_offset_to_key(b, rw_aux_tree(b, t)[j].offset);
506 static void rw_aux_tree_set(const struct btree *b, struct bset_tree *t,
507 unsigned j, struct bkey_packed *k)
509 EBUG_ON(k >= btree_bkey_last(b, t));
511 rw_aux_tree(b, t)[j] = (struct rw_aux_tree) {
512 .offset = __btree_node_key_to_offset(b, k),
513 .k = bkey_unpack_pos(b, k),
517 static void bch2_bset_verify_rw_aux_tree(struct btree *b,
520 struct bkey_packed *k = btree_bkey_first(b, t);
523 if (!bch2_expensive_debug_checks)
526 BUG_ON(bset_has_ro_aux_tree(t));
528 if (!bset_has_rw_aux_tree(t))
532 BUG_ON(rw_aux_to_bkey(b, t, j) != k);
536 if (rw_aux_to_bkey(b, t, j) == k) {
537 BUG_ON(bpos_cmp(rw_aux_tree(b, t)[j].k,
538 bkey_unpack_pos(b, k)));
543 BUG_ON(rw_aux_tree(b, t)[j].offset <=
544 rw_aux_tree(b, t)[j - 1].offset);
548 BUG_ON(k >= btree_bkey_last(b, t));
552 /* returns idx of first entry >= offset: */
553 static unsigned rw_aux_tree_bsearch(struct btree *b,
557 unsigned bset_offs = offset - btree_bkey_first_offset(t);
558 unsigned bset_u64s = t->end_offset - btree_bkey_first_offset(t);
559 unsigned idx = bset_u64s ? bset_offs * t->size / bset_u64s : 0;
561 EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
563 EBUG_ON(idx > t->size);
565 while (idx < t->size &&
566 rw_aux_tree(b, t)[idx].offset < offset)
570 rw_aux_tree(b, t)[idx - 1].offset >= offset)
573 EBUG_ON(idx < t->size &&
574 rw_aux_tree(b, t)[idx].offset < offset);
575 EBUG_ON(idx && rw_aux_tree(b, t)[idx - 1].offset >= offset);
576 EBUG_ON(idx + 1 < t->size &&
577 rw_aux_tree(b, t)[idx].offset ==
578 rw_aux_tree(b, t)[idx + 1].offset);
583 static inline unsigned bkey_mantissa(const struct bkey_packed *k,
584 const struct bkey_float *f,
589 EBUG_ON(!bkey_packed(k));
591 v = get_unaligned((u64 *) (((u8 *) k->_data) + (f->exponent >> 3)));
594 * In little endian, we're shifting off low bits (and then the bits we
595 * want are at the low end), in big endian we're shifting off high bits
596 * (and then the bits we want are at the high end, so we shift them
599 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
600 v >>= f->exponent & 7;
602 v >>= 64 - (f->exponent & 7) - BKEY_MANTISSA_BITS;
608 static inline void __make_bfloat(struct btree *b, struct bset_tree *t,
610 struct bkey_packed *min_key,
611 struct bkey_packed *max_key)
613 struct bkey_float *f = bkey_float(b, t, j);
614 struct bkey_packed *m = tree_to_bkey(b, t, j);
615 struct bkey_packed *l = is_power_of_2(j)
617 : tree_to_prev_bkey(b, t, j >> ffs(j));
618 struct bkey_packed *r = is_power_of_2(j + 1)
620 : tree_to_bkey(b, t, j >> (ffz(j) + 1));
622 int shift, exponent, high_bit;
625 * for failed bfloats, the lookup code falls back to comparing against
629 if (!bkey_packed(l) || !bkey_packed(r) || !bkey_packed(m) ||
631 f->exponent = BFLOAT_FAILED_UNPACKED;
636 * The greatest differing bit of l and r is the first bit we must
637 * include in the bfloat mantissa we're creating in order to do
638 * comparisons - that bit always becomes the high bit of
639 * bfloat->mantissa, and thus the exponent we're calculating here is
640 * the position of what will become the low bit in bfloat->mantissa:
642 * Note that this may be negative - we may be running off the low end
643 * of the key: we handle this later:
645 high_bit = max(bch2_bkey_greatest_differing_bit(b, l, r),
646 min_t(unsigned, BKEY_MANTISSA_BITS, b->nr_key_bits) - 1);
647 exponent = high_bit - (BKEY_MANTISSA_BITS - 1);
650 * Then we calculate the actual shift value, from the start of the key
651 * (k->_data), to get the key bits starting at exponent:
653 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
654 shift = (int) (b->format.key_u64s * 64 - b->nr_key_bits) + exponent;
656 EBUG_ON(shift + BKEY_MANTISSA_BITS > b->format.key_u64s * 64);
658 shift = high_bit_offset +
663 EBUG_ON(shift < KEY_PACKED_BITS_START);
665 EBUG_ON(shift < 0 || shift >= BFLOAT_FAILED);
668 mantissa = bkey_mantissa(m, f, j);
671 * If we've got garbage bits, set them to all 1s - it's legal for the
672 * bfloat to compare larger than the original key, but not smaller:
675 mantissa |= ~(~0U << -exponent);
677 f->mantissa = mantissa;
680 static void make_bfloat(struct btree *b, struct bset_tree *t,
682 struct bkey_packed *min_key,
683 struct bkey_packed *max_key)
687 if (is_power_of_2(j) &&
689 if (!bkey_pack_pos(min_key, b->data->min_key, b)) {
690 k = (void *) min_key;
692 k->k.p = b->data->min_key;
696 if (is_power_of_2(j + 1) &&
698 if (!bkey_pack_pos(max_key, b->data->max_key, b)) {
699 k = (void *) max_key;
701 k->k.p = b->data->max_key;
705 __make_bfloat(b, t, j, min_key, max_key);
708 /* bytes remaining - only valid for last bset: */
709 static unsigned __bset_tree_capacity(const struct btree *b, const struct bset_tree *t)
711 bset_aux_tree_verify(b);
713 return btree_aux_data_bytes(b) - t->aux_data_offset * sizeof(u64);
716 static unsigned bset_ro_tree_capacity(const struct btree *b, const struct bset_tree *t)
718 return __bset_tree_capacity(b, t) /
719 (sizeof(struct bkey_float) + sizeof(u8));
722 static unsigned bset_rw_tree_capacity(const struct btree *b, const struct bset_tree *t)
724 return __bset_tree_capacity(b, t) / sizeof(struct rw_aux_tree);
727 static noinline void __build_rw_aux_tree(struct btree *b, struct bset_tree *t)
729 struct bkey_packed *k;
732 t->extra = BSET_RW_AUX_TREE_VAL;
733 rw_aux_tree(b, t)[0].offset =
734 __btree_node_key_to_offset(b, btree_bkey_first(b, t));
736 bset_tree_for_each_key(b, t, k) {
737 if (t->size == bset_rw_tree_capacity(b, t))
740 if ((void *) k - (void *) rw_aux_to_bkey(b, t, t->size - 1) >
742 rw_aux_tree_set(b, t, t->size++, k);
746 static noinline void __build_ro_aux_tree(struct btree *b, struct bset_tree *t)
748 struct bkey_packed *prev = NULL, *k = btree_bkey_first(b, t);
749 struct bkey_i min_key, max_key;
750 unsigned j, cacheline = 1;
752 t->size = min(bkey_to_cacheline(b, t, btree_bkey_last(b, t)),
753 bset_ro_tree_capacity(b, t));
757 t->extra = BSET_NO_AUX_TREE_VAL;
761 t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
763 /* First we figure out where the first key in each cacheline is */
764 eytzinger1_for_each(j, t->size) {
765 while (bkey_to_cacheline(b, t, k) < cacheline)
766 prev = k, k = bkey_next(k);
768 if (k >= btree_bkey_last(b, t)) {
769 /* XXX: this path sucks */
774 ro_aux_tree_prev(b, t)[j] = prev->u64s;
775 bkey_float(b, t, j)->key_offset =
776 bkey_to_cacheline_offset(b, t, cacheline++, k);
778 EBUG_ON(tree_to_prev_bkey(b, t, j) != prev);
779 EBUG_ON(tree_to_bkey(b, t, j) != k);
782 while (k != btree_bkey_last(b, t))
783 prev = k, k = bkey_next(k);
785 if (!bkey_pack_pos(bkey_to_packed(&min_key), b->data->min_key, b)) {
786 bkey_init(&min_key.k);
787 min_key.k.p = b->data->min_key;
790 if (!bkey_pack_pos(bkey_to_packed(&max_key), b->data->max_key, b)) {
791 bkey_init(&max_key.k);
792 max_key.k.p = b->data->max_key;
795 /* Then we build the tree */
796 eytzinger1_for_each(j, t->size)
797 __make_bfloat(b, t, j,
798 bkey_to_packed(&min_key),
799 bkey_to_packed(&max_key));
802 static void bset_alloc_tree(struct btree *b, struct bset_tree *t)
806 for (i = b->set; i != t; i++)
807 BUG_ON(bset_has_rw_aux_tree(i));
809 bch2_bset_set_no_aux_tree(b, t);
811 /* round up to next cacheline: */
812 t->aux_data_offset = round_up(bset_aux_tree_buf_start(b, t),
813 SMP_CACHE_BYTES / sizeof(u64));
815 bset_aux_tree_verify(b);
818 void bch2_bset_build_aux_tree(struct btree *b, struct bset_tree *t,
822 ? bset_has_rw_aux_tree(t)
823 : bset_has_ro_aux_tree(t))
826 bset_alloc_tree(b, t);
828 if (!__bset_tree_capacity(b, t))
832 __build_rw_aux_tree(b, t);
834 __build_ro_aux_tree(b, t);
836 bset_aux_tree_verify(b);
839 void bch2_bset_init_first(struct btree *b, struct bset *i)
845 memset(i, 0, sizeof(*i));
846 get_random_bytes(&i->seq, sizeof(i->seq));
847 SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
849 t = &b->set[b->nsets++];
850 set_btree_bset(b, t, i);
853 void bch2_bset_init_next(struct bch_fs *c, struct btree *b,
854 struct btree_node_entry *bne)
856 struct bset *i = &bne->keys;
859 BUG_ON(bset_byte_offset(b, bne) >= btree_bytes(c));
860 BUG_ON((void *) bne < (void *) btree_bkey_last(b, bset_tree_last(b)));
861 BUG_ON(b->nsets >= MAX_BSETS);
863 memset(i, 0, sizeof(*i));
864 i->seq = btree_bset_first(b)->seq;
865 SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
867 t = &b->set[b->nsets++];
868 set_btree_bset(b, t, i);
872 * find _some_ key in the same bset as @k that precedes @k - not necessarily the
873 * immediate predecessor:
875 static struct bkey_packed *__bkey_prev(struct btree *b, struct bset_tree *t,
876 struct bkey_packed *k)
878 struct bkey_packed *p;
882 EBUG_ON(k < btree_bkey_first(b, t) ||
883 k > btree_bkey_last(b, t));
885 if (k == btree_bkey_first(b, t))
888 switch (bset_aux_tree_type(t)) {
889 case BSET_NO_AUX_TREE:
890 p = btree_bkey_first(b, t);
892 case BSET_RO_AUX_TREE:
893 j = min_t(unsigned, t->size - 1, bkey_to_cacheline(b, t, k));
896 p = j ? tree_to_bkey(b, t,
897 __inorder_to_eytzinger1(j--,
899 : btree_bkey_first(b, t);
902 case BSET_RW_AUX_TREE:
903 offset = __btree_node_key_to_offset(b, k);
904 j = rw_aux_tree_bsearch(b, t, offset);
905 p = j ? rw_aux_to_bkey(b, t, j - 1)
906 : btree_bkey_first(b, t);
913 struct bkey_packed *bch2_bkey_prev_filter(struct btree *b,
915 struct bkey_packed *k,
916 unsigned min_key_type)
918 struct bkey_packed *p, *i, *ret = NULL, *orig_k = k;
920 while ((p = __bkey_prev(b, t, k)) && !ret) {
921 for (i = p; i != k; i = bkey_next(i))
922 if (i->type >= min_key_type)
928 if (bch2_expensive_debug_checks) {
929 BUG_ON(ret >= orig_k);
933 : btree_bkey_first(b, t);
936 BUG_ON(i->type >= min_key_type);
944 static void rw_aux_tree_fix_invalidated_key(struct btree *b,
946 struct bkey_packed *k)
948 unsigned offset = __btree_node_key_to_offset(b, k);
949 unsigned j = rw_aux_tree_bsearch(b, t, offset);
952 rw_aux_tree(b, t)[j].offset == offset)
953 rw_aux_tree_set(b, t, j, k);
955 bch2_bset_verify_rw_aux_tree(b, t);
958 static void ro_aux_tree_fix_invalidated_key(struct btree *b,
960 struct bkey_packed *k)
962 struct bkey_packed min_key, max_key;
965 EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
967 /* signal to make_bfloat() that they're uninitialized: */
968 min_key.u64s = max_key.u64s = 0;
970 if (bkey_next(k) == btree_bkey_last(b, t)) {
971 for (j = 1; j < t->size; j = j * 2 + 1)
972 make_bfloat(b, t, j, &min_key, &max_key);
975 inorder = bkey_to_cacheline(b, t, k);
979 j = __inorder_to_eytzinger1(inorder, t->size, t->extra);
981 if (k == tree_to_bkey(b, t, j)) {
982 /* Fix the node this key corresponds to */
983 make_bfloat(b, t, j, &min_key, &max_key);
985 /* Children for which this key is the right boundary */
986 for (j = eytzinger1_left_child(j);
988 j = eytzinger1_right_child(j))
989 make_bfloat(b, t, j, &min_key, &max_key);
993 if (inorder + 1 < t->size) {
994 j = __inorder_to_eytzinger1(inorder + 1, t->size, t->extra);
996 if (k == tree_to_prev_bkey(b, t, j)) {
997 make_bfloat(b, t, j, &min_key, &max_key);
999 /* Children for which this key is the left boundary */
1000 for (j = eytzinger1_right_child(j);
1002 j = eytzinger1_left_child(j))
1003 make_bfloat(b, t, j, &min_key, &max_key);
1009 * bch2_bset_fix_invalidated_key() - given an existing key @k that has been
1010 * modified, fix any auxiliary search tree by remaking all the nodes in the
1011 * auxiliary search tree that @k corresponds to
1013 void bch2_bset_fix_invalidated_key(struct btree *b, struct bkey_packed *k)
1015 struct bset_tree *t = bch2_bkey_to_bset(b, k);
1017 switch (bset_aux_tree_type(t)) {
1018 case BSET_NO_AUX_TREE:
1020 case BSET_RO_AUX_TREE:
1021 ro_aux_tree_fix_invalidated_key(b, t, k);
1023 case BSET_RW_AUX_TREE:
1024 rw_aux_tree_fix_invalidated_key(b, t, k);
1029 static void bch2_bset_fix_lookup_table(struct btree *b,
1030 struct bset_tree *t,
1031 struct bkey_packed *_where,
1032 unsigned clobber_u64s,
1035 int shift = new_u64s - clobber_u64s;
1036 unsigned l, j, where = __btree_node_key_to_offset(b, _where);
1038 EBUG_ON(bset_has_ro_aux_tree(t));
1040 if (!bset_has_rw_aux_tree(t))
1043 /* returns first entry >= where */
1044 l = rw_aux_tree_bsearch(b, t, where);
1046 if (!l) /* never delete first entry */
1048 else if (l < t->size &&
1049 where < t->end_offset &&
1050 rw_aux_tree(b, t)[l].offset == where)
1051 rw_aux_tree_set(b, t, l++, _where);
1057 rw_aux_tree(b, t)[j].offset < where + clobber_u64s;
1062 rw_aux_tree(b, t)[j].offset + shift ==
1063 rw_aux_tree(b, t)[l - 1].offset)
1066 memmove(&rw_aux_tree(b, t)[l],
1067 &rw_aux_tree(b, t)[j],
1068 (void *) &rw_aux_tree(b, t)[t->size] -
1069 (void *) &rw_aux_tree(b, t)[j]);
1072 for (j = l; j < t->size; j++)
1073 rw_aux_tree(b, t)[j].offset += shift;
1075 EBUG_ON(l < t->size &&
1076 rw_aux_tree(b, t)[l].offset ==
1077 rw_aux_tree(b, t)[l - 1].offset);
1079 if (t->size < bset_rw_tree_capacity(b, t) &&
1081 ? rw_aux_tree(b, t)[l].offset
1083 rw_aux_tree(b, t)[l - 1].offset >
1084 L1_CACHE_BYTES / sizeof(u64)) {
1085 struct bkey_packed *start = rw_aux_to_bkey(b, t, l - 1);
1086 struct bkey_packed *end = l < t->size
1087 ? rw_aux_to_bkey(b, t, l)
1088 : btree_bkey_last(b, t);
1089 struct bkey_packed *k = start;
1096 if ((void *) k - (void *) start >= L1_CACHE_BYTES) {
1097 memmove(&rw_aux_tree(b, t)[l + 1],
1098 &rw_aux_tree(b, t)[l],
1099 (void *) &rw_aux_tree(b, t)[t->size] -
1100 (void *) &rw_aux_tree(b, t)[l]);
1102 rw_aux_tree_set(b, t, l, k);
1108 bch2_bset_verify_rw_aux_tree(b, t);
1109 bset_aux_tree_verify(b);
1112 void bch2_bset_insert(struct btree *b,
1113 struct btree_node_iter *iter,
1114 struct bkey_packed *where,
1115 struct bkey_i *insert,
1116 unsigned clobber_u64s)
1118 struct bkey_format *f = &b->format;
1119 struct bset_tree *t = bset_tree_last(b);
1120 struct bkey_packed packed, *src = bkey_to_packed(insert);
1122 bch2_bset_verify_rw_aux_tree(b, t);
1123 bch2_verify_insert_pos(b, where, bkey_to_packed(insert), clobber_u64s);
1125 if (bch2_bkey_pack_key(&packed, &insert->k, f))
1128 if (!bkey_deleted(&insert->k))
1129 btree_keys_account_key_add(&b->nr, t - b->set, src);
1131 if (src->u64s != clobber_u64s) {
1132 u64 *src_p = where->_data + clobber_u64s;
1133 u64 *dst_p = where->_data + src->u64s;
1135 EBUG_ON((int) le16_to_cpu(bset(b, t)->u64s) <
1136 (int) clobber_u64s - src->u64s);
1138 memmove_u64s(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1139 le16_add_cpu(&bset(b, t)->u64s, src->u64s - clobber_u64s);
1140 set_btree_bset_end(b, t);
1143 memcpy_u64s(where, src,
1144 bkeyp_key_u64s(f, src));
1145 memcpy_u64s(bkeyp_val(f, where), &insert->v,
1146 bkeyp_val_u64s(f, src));
1148 if (src->u64s != clobber_u64s)
1149 bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, src->u64s);
1151 bch2_verify_btree_nr_keys(b);
1154 void bch2_bset_delete(struct btree *b,
1155 struct bkey_packed *where,
1156 unsigned clobber_u64s)
1158 struct bset_tree *t = bset_tree_last(b);
1159 u64 *src_p = where->_data + clobber_u64s;
1160 u64 *dst_p = where->_data;
1162 bch2_bset_verify_rw_aux_tree(b, t);
1164 EBUG_ON(le16_to_cpu(bset(b, t)->u64s) < clobber_u64s);
1166 memmove_u64s_down(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1167 le16_add_cpu(&bset(b, t)->u64s, -clobber_u64s);
1168 set_btree_bset_end(b, t);
1170 bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, 0);
1176 static struct bkey_packed *bset_search_write_set(const struct btree *b,
1177 struct bset_tree *t,
1178 struct bpos *search)
1180 unsigned l = 0, r = t->size;
1182 while (l + 1 != r) {
1183 unsigned m = (l + r) >> 1;
1185 if (bpos_cmp(rw_aux_tree(b, t)[m].k, *search) < 0)
1191 return rw_aux_to_bkey(b, t, l);
1194 static inline void prefetch_four_cachelines(void *p)
1196 #ifdef CONFIG_X86_64
1197 asm("prefetcht0 (-127 + 64 * 0)(%0);"
1198 "prefetcht0 (-127 + 64 * 1)(%0);"
1199 "prefetcht0 (-127 + 64 * 2)(%0);"
1200 "prefetcht0 (-127 + 64 * 3)(%0);"
1204 prefetch(p + L1_CACHE_BYTES * 0);
1205 prefetch(p + L1_CACHE_BYTES * 1);
1206 prefetch(p + L1_CACHE_BYTES * 2);
1207 prefetch(p + L1_CACHE_BYTES * 3);
1211 static inline bool bkey_mantissa_bits_dropped(const struct btree *b,
1212 const struct bkey_float *f,
1215 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
1216 unsigned key_bits_start = b->format.key_u64s * 64 - b->nr_key_bits;
1218 return f->exponent > key_bits_start;
1220 unsigned key_bits_end = high_bit_offset + b->nr_key_bits;
1222 return f->exponent + BKEY_MANTISSA_BITS < key_bits_end;
1227 static struct bkey_packed *bset_search_tree(const struct btree *b,
1228 const struct bset_tree *t,
1229 const struct bpos *search,
1230 const struct bkey_packed *packed_search)
1232 struct ro_aux_tree *base = ro_aux_tree_base(b, t);
1233 struct bkey_float *f;
1234 struct bkey_packed *k;
1235 unsigned inorder, n = 1, l, r;
1239 if (likely(n << 4 < t->size))
1240 prefetch(&base->f[n << 4]);
1243 if (unlikely(f->exponent >= BFLOAT_FAILED))
1247 r = bkey_mantissa(packed_search, f, n);
1249 if (unlikely(l == r) && bkey_mantissa_bits_dropped(b, f, n))
1252 n = n * 2 + (l < r);
1255 k = tree_to_bkey(b, t, n);
1256 cmp = bkey_cmp_p_or_unp(b, k, packed_search, search);
1260 n = n * 2 + (cmp < 0);
1261 } while (n < t->size);
1263 inorder = __eytzinger1_to_inorder(n >> 1, t->size, t->extra);
1266 * n would have been the node we recursed to - the low bit tells us if
1267 * we recursed left or recursed right.
1269 if (likely(!(n & 1))) {
1271 if (unlikely(!inorder))
1272 return btree_bkey_first(b, t);
1274 f = &base->f[eytzinger1_prev(n >> 1, t->size)];
1277 return cacheline_to_bkey(b, t, inorder, f->key_offset);
1280 static __always_inline __flatten
1281 struct bkey_packed *__bch2_bset_search(struct btree *b,
1282 struct bset_tree *t,
1283 struct bpos *search,
1284 const struct bkey_packed *lossy_packed_search)
1288 * First, we search for a cacheline, then lastly we do a linear search
1289 * within that cacheline.
1291 * To search for the cacheline, there's three different possibilities:
1292 * * The set is too small to have a search tree, so we just do a linear
1293 * search over the whole set.
1294 * * The set is the one we're currently inserting into; keeping a full
1295 * auxiliary search tree up to date would be too expensive, so we
1296 * use a much simpler lookup table to do a binary search -
1297 * bset_search_write_set().
1298 * * Or we use the auxiliary search tree we constructed earlier -
1299 * bset_search_tree()
1302 switch (bset_aux_tree_type(t)) {
1303 case BSET_NO_AUX_TREE:
1304 return btree_bkey_first(b, t);
1305 case BSET_RW_AUX_TREE:
1306 return bset_search_write_set(b, t, search);
1307 case BSET_RO_AUX_TREE:
1308 return bset_search_tree(b, t, search, lossy_packed_search);
1314 static __always_inline __flatten
1315 struct bkey_packed *bch2_bset_search_linear(struct btree *b,
1316 struct bset_tree *t,
1317 struct bpos *search,
1318 struct bkey_packed *packed_search,
1319 const struct bkey_packed *lossy_packed_search,
1320 struct bkey_packed *m)
1322 if (lossy_packed_search)
1323 while (m != btree_bkey_last(b, t) &&
1324 bkey_iter_cmp_p_or_unp(b, m,
1325 lossy_packed_search, search) < 0)
1329 while (m != btree_bkey_last(b, t) &&
1330 bkey_iter_pos_cmp(b, m, search) < 0)
1333 if (bch2_expensive_debug_checks) {
1334 struct bkey_packed *prev = bch2_bkey_prev_all(b, t, m);
1337 bkey_iter_cmp_p_or_unp(b, prev,
1338 packed_search, search) >= 0);
1344 /* Btree node iterator */
1346 static inline void __bch2_btree_node_iter_push(struct btree_node_iter *iter,
1348 const struct bkey_packed *k,
1349 const struct bkey_packed *end)
1352 struct btree_node_iter_set *pos;
1354 btree_node_iter_for_each(iter, pos)
1357 BUG_ON(pos >= iter->data + ARRAY_SIZE(iter->data));
1358 *pos = (struct btree_node_iter_set) {
1359 __btree_node_key_to_offset(b, k),
1360 __btree_node_key_to_offset(b, end)
1365 void bch2_btree_node_iter_push(struct btree_node_iter *iter,
1367 const struct bkey_packed *k,
1368 const struct bkey_packed *end)
1370 __bch2_btree_node_iter_push(iter, b, k, end);
1371 bch2_btree_node_iter_sort(iter, b);
1374 noinline __flatten __attribute__((cold))
1375 static void btree_node_iter_init_pack_failed(struct btree_node_iter *iter,
1376 struct btree *b, struct bpos *search)
1378 struct bkey_packed *k;
1380 trace_bkey_pack_pos_fail(search);
1382 bch2_btree_node_iter_init_from_start(iter, b);
1384 while ((k = bch2_btree_node_iter_peek(iter, b)) &&
1385 bkey_iter_pos_cmp(b, k, search) < 0)
1386 bch2_btree_node_iter_advance(iter, b);
1390 * bch_btree_node_iter_init - initialize a btree node iterator, starting from a
1393 * Main entry point to the lookup code for individual btree nodes:
1397 * When you don't filter out deleted keys, btree nodes _do_ contain duplicate
1398 * keys. This doesn't matter for most code, but it does matter for lookups.
1400 * Some adjacent keys with a string of equal keys:
1403 * If you search for k, the lookup code isn't guaranteed to return you any
1404 * specific k. The lookup code is conceptually doing a binary search and
1405 * iterating backwards is very expensive so if the pivot happens to land at the
1406 * last k that's what you'll get.
1408 * This works out ok, but it's something to be aware of:
1410 * - For non extents, we guarantee that the live key comes last - see
1411 * btree_node_iter_cmp(), keys_out_of_order(). So the duplicates you don't
1412 * see will only be deleted keys you don't care about.
1414 * - For extents, deleted keys sort last (see the comment at the top of this
1415 * file). But when you're searching for extents, you actually want the first
1416 * key strictly greater than your search key - an extent that compares equal
1417 * to the search key is going to have 0 sectors after the search key.
1419 * But this does mean that we can't just search for
1420 * bpos_successor(start_of_range) to get the first extent that overlaps with
1421 * the range we want - if we're unlucky and there's an extent that ends
1422 * exactly where we searched, then there could be a deleted key at the same
1423 * position and we'd get that when we search instead of the preceding extent
1426 * So we've got to search for start_of_range, then after the lookup iterate
1427 * past any extents that compare equal to the position we searched for.
1430 void bch2_btree_node_iter_init(struct btree_node_iter *iter,
1431 struct btree *b, struct bpos *search)
1433 struct bkey_packed p, *packed_search = NULL;
1434 struct btree_node_iter_set *pos = iter->data;
1435 struct bkey_packed *k[MAX_BSETS];
1438 EBUG_ON(bpos_cmp(*search, b->data->min_key) < 0);
1439 EBUG_ON(bpos_cmp(*search, b->data->max_key) > 0);
1440 bset_aux_tree_verify(b);
1442 memset(iter, 0, sizeof(*iter));
1444 switch (bch2_bkey_pack_pos_lossy(&p, *search, b)) {
1445 case BKEY_PACK_POS_EXACT:
1448 case BKEY_PACK_POS_SMALLER:
1449 packed_search = NULL;
1451 case BKEY_PACK_POS_FAIL:
1452 btree_node_iter_init_pack_failed(iter, b, search);
1456 for (i = 0; i < b->nsets; i++) {
1457 k[i] = __bch2_bset_search(b, b->set + i, search, &p);
1458 prefetch_four_cachelines(k[i]);
1461 for (i = 0; i < b->nsets; i++) {
1462 struct bset_tree *t = b->set + i;
1463 struct bkey_packed *end = btree_bkey_last(b, t);
1465 k[i] = bch2_bset_search_linear(b, t, search,
1466 packed_search, &p, k[i]);
1468 *pos++ = (struct btree_node_iter_set) {
1469 __btree_node_key_to_offset(b, k[i]),
1470 __btree_node_key_to_offset(b, end)
1474 bch2_btree_node_iter_sort(iter, b);
1477 void bch2_btree_node_iter_init_from_start(struct btree_node_iter *iter,
1480 struct bset_tree *t;
1482 memset(iter, 0, sizeof(*iter));
1485 __bch2_btree_node_iter_push(iter, b,
1486 btree_bkey_first(b, t),
1487 btree_bkey_last(b, t));
1488 bch2_btree_node_iter_sort(iter, b);
1491 struct bkey_packed *bch2_btree_node_iter_bset_pos(struct btree_node_iter *iter,
1493 struct bset_tree *t)
1495 struct btree_node_iter_set *set;
1497 btree_node_iter_for_each(iter, set)
1498 if (set->end == t->end_offset)
1499 return __btree_node_offset_to_key(b, set->k);
1501 return btree_bkey_last(b, t);
1504 static inline bool btree_node_iter_sort_two(struct btree_node_iter *iter,
1510 if ((ret = (btree_node_iter_cmp(b,
1512 iter->data[first + 1]) > 0)))
1513 swap(iter->data[first], iter->data[first + 1]);
1517 void bch2_btree_node_iter_sort(struct btree_node_iter *iter,
1520 /* unrolled bubble sort: */
1522 if (!__btree_node_iter_set_end(iter, 2)) {
1523 btree_node_iter_sort_two(iter, b, 0);
1524 btree_node_iter_sort_two(iter, b, 1);
1527 if (!__btree_node_iter_set_end(iter, 1))
1528 btree_node_iter_sort_two(iter, b, 0);
1531 void bch2_btree_node_iter_set_drop(struct btree_node_iter *iter,
1532 struct btree_node_iter_set *set)
1534 struct btree_node_iter_set *last =
1535 iter->data + ARRAY_SIZE(iter->data) - 1;
1537 memmove(&set[0], &set[1], (void *) last - (void *) set);
1538 *last = (struct btree_node_iter_set) { 0, 0 };
1541 static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1544 iter->data->k += __bch2_btree_node_iter_peek_all(iter, b)->u64s;
1546 EBUG_ON(iter->data->k > iter->data->end);
1548 while (!__btree_node_iter_set_end(iter, 0) &&
1549 !__bch2_btree_node_iter_peek_all(iter, b)->u64s)
1552 if (unlikely(__btree_node_iter_set_end(iter, 0))) {
1553 bch2_btree_node_iter_set_drop(iter, iter->data);
1557 if (__btree_node_iter_set_end(iter, 1))
1560 if (!btree_node_iter_sort_two(iter, b, 0))
1563 if (__btree_node_iter_set_end(iter, 2))
1566 btree_node_iter_sort_two(iter, b, 1);
1569 void bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1572 if (bch2_expensive_debug_checks) {
1573 bch2_btree_node_iter_verify(iter, b);
1574 bch2_btree_node_iter_next_check(iter, b);
1577 __bch2_btree_node_iter_advance(iter, b);
1583 struct bkey_packed *bch2_btree_node_iter_prev_all(struct btree_node_iter *iter,
1586 struct bkey_packed *k, *prev = NULL;
1587 struct btree_node_iter_set *set;
1588 struct bset_tree *t;
1591 if (bch2_expensive_debug_checks)
1592 bch2_btree_node_iter_verify(iter, b);
1594 for_each_bset(b, t) {
1595 k = bch2_bkey_prev_all(b, t,
1596 bch2_btree_node_iter_bset_pos(iter, b, t));
1598 (!prev || bkey_iter_cmp(b, k, prev) > 0)) {
1600 end = t->end_offset;
1608 * We're manually memmoving instead of just calling sort() to ensure the
1609 * prev we picked ends up in slot 0 - sort won't necessarily put it
1610 * there because of duplicate deleted keys:
1612 btree_node_iter_for_each(iter, set)
1613 if (set->end == end)
1616 BUG_ON(set != &iter->data[__btree_node_iter_used(iter)]);
1618 BUG_ON(set >= iter->data + ARRAY_SIZE(iter->data));
1620 memmove(&iter->data[1],
1622 (void *) set - (void *) &iter->data[0]);
1624 iter->data[0].k = __btree_node_key_to_offset(b, prev);
1625 iter->data[0].end = end;
1627 if (bch2_expensive_debug_checks)
1628 bch2_btree_node_iter_verify(iter, b);
1632 struct bkey_packed *bch2_btree_node_iter_prev(struct btree_node_iter *iter,
1635 struct bkey_packed *prev;
1638 prev = bch2_btree_node_iter_prev_all(iter, b);
1639 } while (prev && bkey_deleted(prev));
1644 struct bkey_s_c bch2_btree_node_iter_peek_unpack(struct btree_node_iter *iter,
1648 struct bkey_packed *k = bch2_btree_node_iter_peek(iter, b);
1650 return k ? bkey_disassemble(b, k, u) : bkey_s_c_null;
1655 void bch2_btree_keys_stats(struct btree *b, struct bset_stats *stats)
1657 struct bset_tree *t;
1659 for_each_bset(b, t) {
1660 enum bset_aux_tree_type type = bset_aux_tree_type(t);
1663 stats->sets[type].nr++;
1664 stats->sets[type].bytes += le16_to_cpu(bset(b, t)->u64s) *
1667 if (bset_has_ro_aux_tree(t)) {
1668 stats->floats += t->size - 1;
1670 for (j = 1; j < t->size; j++)
1672 bkey_float(b, t, j)->exponent ==
1678 void bch2_bfloat_to_text(struct printbuf *out, struct btree *b,
1679 struct bkey_packed *k)
1681 struct bset_tree *t = bch2_bkey_to_bset(b, k);
1683 unsigned j, inorder;
1685 if (out->pos != out->end)
1688 if (!bset_has_ro_aux_tree(t))
1691 inorder = bkey_to_cacheline(b, t, k);
1692 if (!inorder || inorder >= t->size)
1695 j = __inorder_to_eytzinger1(inorder, t->size, t->extra);
1696 if (k != tree_to_bkey(b, t, j))
1699 switch (bkey_float(b, t, j)->exponent) {
1701 uk = bkey_unpack_key(b, k);
1703 " failed unpacked at depth %u\n"
1706 bch2_bpos_to_text(out, uk.p);