diff options
Diffstat (limited to 'fs/bcachefs/bset.c')
| -rw-r--r-- | fs/bcachefs/bset.c | 1592 |
1 files changed, 1592 insertions, 0 deletions
diff --git a/fs/bcachefs/bset.c b/fs/bcachefs/bset.c new file mode 100644 index 0000000000..bb73ba9017 --- /dev/null +++ b/fs/bcachefs/bset.c @@ -0,0 +1,1592 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Code for working with individual keys, and sorted sets of keys with in a + * btree node + * + * Copyright 2012 Google, Inc. + */ + +#include "bcachefs.h" +#include "btree_cache.h" +#include "bset.h" +#include "eytzinger.h" +#include "trace.h" +#include "util.h" + +#include <asm/unaligned.h> +#include <linux/console.h> +#include <linux/random.h> +#include <linux/prefetch.h> + +static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *, + struct btree *); + +static inline unsigned __btree_node_iter_used(struct btree_node_iter *iter) +{ + unsigned n = ARRAY_SIZE(iter->data); + + while (n && __btree_node_iter_set_end(iter, n - 1)) + --n; + + return n; +} + +struct bset_tree *bch2_bkey_to_bset(struct btree *b, struct bkey_packed *k) +{ + return bch2_bkey_to_bset_inlined(b, k); +} + +/* + * There are never duplicate live keys in the btree - but including keys that + * have been flagged as deleted (and will be cleaned up later) we _will_ see + * duplicates. + * + * Thus the sort order is: usual key comparison first, but for keys that compare + * equal the deleted key(s) come first, and the (at most one) live version comes + * last. + * + * The main reason for this is insertion: to handle overwrites, we first iterate + * over keys that compare equal to our insert key, and then insert immediately + * prior to the first key greater than the key we're inserting - our insert + * position will be after all keys that compare equal to our insert key, which + * by the time we actually do the insert will all be deleted. + */ + +void bch2_dump_bset(struct bch_fs *c, struct btree *b, + struct bset *i, unsigned set) +{ + struct bkey_packed *_k, *_n; + struct bkey uk, n; + struct bkey_s_c k; + struct printbuf buf = PRINTBUF; + + if (!i->u64s) + return; + + for (_k = i->start; + _k < vstruct_last(i); + _k = _n) { + _n = bkey_p_next(_k); + + k = bkey_disassemble(b, _k, &uk); + + printbuf_reset(&buf); + if (c) + bch2_bkey_val_to_text(&buf, c, k); + else + bch2_bkey_to_text(&buf, k.k); + printk(KERN_ERR "block %u key %5zu: %s\n", set, + _k->_data - i->_data, buf.buf); + + if (_n == vstruct_last(i)) + continue; + + n = bkey_unpack_key(b, _n); + + if (bpos_lt(n.p, k.k->p)) { + printk(KERN_ERR "Key skipped backwards\n"); + continue; + } + + if (!bkey_deleted(k.k) && bpos_eq(n.p, k.k->p)) + printk(KERN_ERR "Duplicate keys\n"); + } + + printbuf_exit(&buf); +} + +void bch2_dump_btree_node(struct bch_fs *c, struct btree *b) +{ + struct bset_tree *t; + + console_lock(); + for_each_bset(b, t) + bch2_dump_bset(c, b, bset(b, t), t - b->set); + console_unlock(); +} + +void bch2_dump_btree_node_iter(struct btree *b, + struct btree_node_iter *iter) +{ + struct btree_node_iter_set *set; + struct printbuf buf = PRINTBUF; + + printk(KERN_ERR "btree node iter with %u/%u sets:\n", + __btree_node_iter_used(iter), b->nsets); + + btree_node_iter_for_each(iter, set) { + struct bkey_packed *k = __btree_node_offset_to_key(b, set->k); + struct bset_tree *t = bch2_bkey_to_bset(b, k); + struct bkey uk = bkey_unpack_key(b, k); + + printbuf_reset(&buf); + bch2_bkey_to_text(&buf, &uk); + printk(KERN_ERR "set %zu key %u: %s\n", + t - b->set, set->k, buf.buf); + } + + printbuf_exit(&buf); +} + +#ifdef CONFIG_BCACHEFS_DEBUG + +void __bch2_verify_btree_nr_keys(struct btree *b) +{ + struct bset_tree *t; + struct bkey_packed *k; + struct btree_nr_keys nr = { 0 }; + + for_each_bset(b, t) + bset_tree_for_each_key(b, t, k) + if (!bkey_deleted(k)) + btree_keys_account_key_add(&nr, t - b->set, k); + + BUG_ON(memcmp(&nr, &b->nr, sizeof(nr))); +} + +static void bch2_btree_node_iter_next_check(struct btree_node_iter *_iter, + struct btree *b) +{ + struct btree_node_iter iter = *_iter; + const struct bkey_packed *k, *n; + + k = bch2_btree_node_iter_peek_all(&iter, b); + __bch2_btree_node_iter_advance(&iter, b); + n = bch2_btree_node_iter_peek_all(&iter, b); + + bkey_unpack_key(b, k); + + if (n && + bkey_iter_cmp(b, k, n) > 0) { + struct btree_node_iter_set *set; + struct bkey ku = bkey_unpack_key(b, k); + struct bkey nu = bkey_unpack_key(b, n); + struct printbuf buf1 = PRINTBUF; + struct printbuf buf2 = PRINTBUF; + + bch2_dump_btree_node(NULL, b); + bch2_bkey_to_text(&buf1, &ku); + bch2_bkey_to_text(&buf2, &nu); + printk(KERN_ERR "out of order/overlapping:\n%s\n%s\n", + buf1.buf, buf2.buf); + printk(KERN_ERR "iter was:"); + + btree_node_iter_for_each(_iter, set) { + struct bkey_packed *k2 = __btree_node_offset_to_key(b, set->k); + struct bset_tree *t = bch2_bkey_to_bset(b, k2); + printk(" [%zi %zi]", t - b->set, + k2->_data - bset(b, t)->_data); + } + panic("\n"); + } +} + +void bch2_btree_node_iter_verify(struct btree_node_iter *iter, + struct btree *b) +{ + struct btree_node_iter_set *set, *s2; + struct bkey_packed *k, *p; + struct bset_tree *t; + + if (bch2_btree_node_iter_end(iter)) + return; + + /* Verify no duplicates: */ + btree_node_iter_for_each(iter, set) { + BUG_ON(set->k > set->end); + btree_node_iter_for_each(iter, s2) + BUG_ON(set != s2 && set->end == s2->end); + } + + /* Verify that set->end is correct: */ + btree_node_iter_for_each(iter, set) { + for_each_bset(b, t) + if (set->end == t->end_offset) + goto found; + BUG(); +found: + BUG_ON(set->k < btree_bkey_first_offset(t) || + set->k >= t->end_offset); + } + + /* Verify iterator is sorted: */ + btree_node_iter_for_each(iter, set) + BUG_ON(set != iter->data && + btree_node_iter_cmp(b, set[-1], set[0]) > 0); + + k = bch2_btree_node_iter_peek_all(iter, b); + + for_each_bset(b, t) { + if (iter->data[0].end == t->end_offset) + continue; + + p = bch2_bkey_prev_all(b, t, + bch2_btree_node_iter_bset_pos(iter, b, t)); + + BUG_ON(p && bkey_iter_cmp(b, k, p) < 0); + } +} + +void bch2_verify_insert_pos(struct btree *b, struct bkey_packed *where, + struct bkey_packed *insert, unsigned clobber_u64s) +{ + struct bset_tree *t = bch2_bkey_to_bset(b, where); + struct bkey_packed *prev = bch2_bkey_prev_all(b, t, where); + struct bkey_packed *next = (void *) ((u64 *) where->_data + clobber_u64s); + struct printbuf buf1 = PRINTBUF; + struct printbuf buf2 = PRINTBUF; +#if 0 + BUG_ON(prev && + bkey_iter_cmp(b, prev, insert) > 0); +#else + if (prev && + bkey_iter_cmp(b, prev, insert) > 0) { + struct bkey k1 = bkey_unpack_key(b, prev); + struct bkey k2 = bkey_unpack_key(b, insert); + + bch2_dump_btree_node(NULL, b); + bch2_bkey_to_text(&buf1, &k1); + bch2_bkey_to_text(&buf2, &k2); + + panic("prev > insert:\n" + "prev key %s\n" + "insert key %s\n", + buf1.buf, buf2.buf); + } +#endif +#if 0 + BUG_ON(next != btree_bkey_last(b, t) && + bkey_iter_cmp(b, insert, next) > 0); +#else + if (next != btree_bkey_last(b, t) && + bkey_iter_cmp(b, insert, next) > 0) { + struct bkey k1 = bkey_unpack_key(b, insert); + struct bkey k2 = bkey_unpack_key(b, next); + + bch2_dump_btree_node(NULL, b); + bch2_bkey_to_text(&buf1, &k1); + bch2_bkey_to_text(&buf2, &k2); + + panic("insert > next:\n" + "insert key %s\n" + "next key %s\n", + buf1.buf, buf2.buf); + } +#endif +} + +#else + +static inline void bch2_btree_node_iter_next_check(struct btree_node_iter *iter, + struct btree *b) {} + +#endif + +/* Auxiliary search trees */ + +#define BFLOAT_FAILED_UNPACKED U8_MAX +#define BFLOAT_FAILED U8_MAX + +struct bkey_float { + u8 exponent; + u8 key_offset; + u16 mantissa; +}; +#define BKEY_MANTISSA_BITS 16 + +static unsigned bkey_float_byte_offset(unsigned idx) +{ + return idx * sizeof(struct bkey_float); +} + +struct ro_aux_tree { + u8 nothing[0]; + struct bkey_float f[]; +}; + +struct rw_aux_tree { + u16 offset; + struct bpos k; +}; + +static unsigned bset_aux_tree_buf_end(const struct bset_tree *t) +{ + BUG_ON(t->aux_data_offset == U16_MAX); + + switch (bset_aux_tree_type(t)) { + case BSET_NO_AUX_TREE: + return t->aux_data_offset; + case BSET_RO_AUX_TREE: + return t->aux_data_offset + + DIV_ROUND_UP(t->size * sizeof(struct bkey_float) + + t->size * sizeof(u8), 8); + case BSET_RW_AUX_TREE: + return t->aux_data_offset + + DIV_ROUND_UP(sizeof(struct rw_aux_tree) * t->size, 8); + default: + BUG(); + } +} + +static unsigned bset_aux_tree_buf_start(const struct btree *b, + const struct bset_tree *t) +{ + return t == b->set + ? DIV_ROUND_UP(b->unpack_fn_len, 8) + : bset_aux_tree_buf_end(t - 1); +} + +static void *__aux_tree_base(const struct btree *b, + const struct bset_tree *t) +{ + return b->aux_data + t->aux_data_offset * 8; +} + +static struct ro_aux_tree *ro_aux_tree_base(const struct btree *b, + const struct bset_tree *t) +{ + EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE); + + return __aux_tree_base(b, t); +} + +static u8 *ro_aux_tree_prev(const struct btree *b, + const struct bset_tree *t) +{ + EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE); + + return __aux_tree_base(b, t) + bkey_float_byte_offset(t->size); +} + +static struct bkey_float *bkey_float(const struct btree *b, + const struct bset_tree *t, + unsigned idx) +{ + return ro_aux_tree_base(b, t)->f + idx; +} + +static void bset_aux_tree_verify(const struct btree *b) +{ +#ifdef CONFIG_BCACHEFS_DEBUG + const struct bset_tree *t; + + for_each_bset(b, t) { + if (t->aux_data_offset == U16_MAX) + continue; + + BUG_ON(t != b->set && + t[-1].aux_data_offset == U16_MAX); + + BUG_ON(t->aux_data_offset < bset_aux_tree_buf_start(b, t)); + BUG_ON(t->aux_data_offset > btree_aux_data_u64s(b)); + BUG_ON(bset_aux_tree_buf_end(t) > btree_aux_data_u64s(b)); + } +#endif +} + +void bch2_btree_keys_init(struct btree *b) +{ + unsigned i; + + b->nsets = 0; + memset(&b->nr, 0, sizeof(b->nr)); + + for (i = 0; i < MAX_BSETS; i++) + b->set[i].data_offset = U16_MAX; + + bch2_bset_set_no_aux_tree(b, b->set); +} + +/* Binary tree stuff for auxiliary search trees */ + +/* + * Cacheline/offset <-> bkey pointer arithmetic: + * + * t->tree is a binary search tree in an array; each node corresponds to a key + * in one cacheline in t->set (BSET_CACHELINE bytes). + * + * This means we don't have to store the full index of the key that a node in + * the binary tree points to; eytzinger1_to_inorder() gives us the cacheline, and + * then bkey_float->m gives us the offset within that cacheline, in units of 8 + * bytes. + * + * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to + * make this work. + * + * To construct the bfloat for an arbitrary key we need to know what the key + * immediately preceding it is: we have to check if the two keys differ in the + * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size + * of the previous key so we can walk backwards to it from t->tree[j]'s key. + */ + +static inline void *bset_cacheline(const struct btree *b, + const struct bset_tree *t, + unsigned cacheline) +{ + return (void *) round_down((unsigned long) btree_bkey_first(b, t), + L1_CACHE_BYTES) + + cacheline * BSET_CACHELINE; +} + +static struct bkey_packed *cacheline_to_bkey(const struct btree *b, + const struct bset_tree *t, + unsigned cacheline, + unsigned offset) +{ + return bset_cacheline(b, t, cacheline) + offset * 8; +} + +static unsigned bkey_to_cacheline(const struct btree *b, + const struct bset_tree *t, + const struct bkey_packed *k) +{ + return ((void *) k - bset_cacheline(b, t, 0)) / BSET_CACHELINE; +} + +static ssize_t __bkey_to_cacheline_offset(const struct btree *b, + const struct bset_tree *t, + unsigned cacheline, + const struct bkey_packed *k) +{ + return (u64 *) k - (u64 *) bset_cacheline(b, t, cacheline); +} + +static unsigned bkey_to_cacheline_offset(const struct btree *b, + const struct bset_tree *t, + unsigned cacheline, + const struct bkey_packed *k) +{ + size_t m = __bkey_to_cacheline_offset(b, t, cacheline, k); + + EBUG_ON(m > U8_MAX); + return m; +} + +static inline struct bkey_packed *tree_to_bkey(const struct btree *b, + const struct bset_tree *t, + unsigned j) +{ + return cacheline_to_bkey(b, t, + __eytzinger1_to_inorder(j, t->size - 1, t->extra), + bkey_float(b, t, j)->key_offset); +} + +static struct bkey_packed *tree_to_prev_bkey(const struct btree *b, + const struct bset_tree *t, + unsigned j) +{ + unsigned prev_u64s = ro_aux_tree_prev(b, t)[j]; + + return (void *) ((u64 *) tree_to_bkey(b, t, j)->_data - prev_u64s); +} + +static struct rw_aux_tree *rw_aux_tree(const struct btree *b, + const struct bset_tree *t) +{ + EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE); + + return __aux_tree_base(b, t); +} + +/* + * For the write set - the one we're currently inserting keys into - we don't + * maintain a full search tree, we just keep a simple lookup table in t->prev. + */ +static struct bkey_packed *rw_aux_to_bkey(const struct btree *b, + struct bset_tree *t, + unsigned j) +{ + return __btree_node_offset_to_key(b, rw_aux_tree(b, t)[j].offset); +} + +static void rw_aux_tree_set(const struct btree *b, struct bset_tree *t, + unsigned j, struct bkey_packed *k) +{ + EBUG_ON(k >= btree_bkey_last(b, t)); + + rw_aux_tree(b, t)[j] = (struct rw_aux_tree) { + .offset = __btree_node_key_to_offset(b, k), + .k = bkey_unpack_pos(b, k), + }; +} + +static void bch2_bset_verify_rw_aux_tree(struct btree *b, + struct bset_tree *t) +{ + struct bkey_packed *k = btree_bkey_first(b, t); + unsigned j = 0; + + if (!bch2_expensive_debug_checks) + return; + + BUG_ON(bset_has_ro_aux_tree(t)); + + if (!bset_has_rw_aux_tree(t)) + return; + + BUG_ON(t->size < 1); + BUG_ON(rw_aux_to_bkey(b, t, j) != k); + + goto start; + while (1) { + if (rw_aux_to_bkey(b, t, j) == k) { + BUG_ON(!bpos_eq(rw_aux_tree(b, t)[j].k, + bkey_unpack_pos(b, k))); +start: + if (++j == t->size) + break; + + BUG_ON(rw_aux_tree(b, t)[j].offset <= + rw_aux_tree(b, t)[j - 1].offset); + } + + k = bkey_p_next(k); + BUG_ON(k >= btree_bkey_last(b, t)); + } +} + +/* returns idx of first entry >= offset: */ +static unsigned rw_aux_tree_bsearch(struct btree *b, + struct bset_tree *t, + unsigned offset) +{ + unsigned bset_offs = offset - btree_bkey_first_offset(t); + unsigned bset_u64s = t->end_offset - btree_bkey_first_offset(t); + unsigned idx = bset_u64s ? bset_offs * t->size / bset_u64s : 0; + + EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE); + EBUG_ON(!t->size); + EBUG_ON(idx > t->size); + + while (idx < t->size && + rw_aux_tree(b, t)[idx].offset < offset) + idx++; + + while (idx && + rw_aux_tree(b, t)[idx - 1].offset >= offset) + idx--; + + EBUG_ON(idx < t->size && + rw_aux_tree(b, t)[idx].offset < offset); + EBUG_ON(idx && rw_aux_tree(b, t)[idx - 1].offset >= offset); + EBUG_ON(idx + 1 < t->size && + rw_aux_tree(b, t)[idx].offset == + rw_aux_tree(b, t)[idx + 1].offset); + + return idx; +} + +static inline unsigned bkey_mantissa(const struct bkey_packed *k, + const struct bkey_float *f, + unsigned idx) +{ + u64 v; + + EBUG_ON(!bkey_packed(k)); + + v = get_unaligned((u64 *) (((u8 *) k->_data) + (f->exponent >> 3))); + + /* + * In little endian, we're shifting off low bits (and then the bits we + * want are at the low end), in big endian we're shifting off high bits + * (and then the bits we want are at the high end, so we shift them + * back down): + */ +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + v >>= f->exponent & 7; +#else + v >>= 64 - (f->exponent & 7) - BKEY_MANTISSA_BITS; +#endif + return (u16) v; +} + +static __always_inline void make_bfloat(struct btree *b, struct bset_tree *t, + unsigned j, + struct bkey_packed *min_key, + struct bkey_packed *max_key) +{ + struct bkey_float *f = bkey_float(b, t, j); + struct bkey_packed *m = tree_to_bkey(b, t, j); + struct bkey_packed *l = is_power_of_2(j) + ? min_key + : tree_to_prev_bkey(b, t, j >> ffs(j)); + struct bkey_packed *r = is_power_of_2(j + 1) + ? max_key + : tree_to_bkey(b, t, j >> (ffz(j) + 1)); + unsigned mantissa; + int shift, exponent, high_bit; + + /* + * for failed bfloats, the lookup code falls back to comparing against + * the original key. + */ + + if (!bkey_packed(l) || !bkey_packed(r) || !bkey_packed(m) || + !b->nr_key_bits) { + f->exponent = BFLOAT_FAILED_UNPACKED; + return; + } + + /* + * The greatest differing bit of l and r is the first bit we must + * include in the bfloat mantissa we're creating in order to do + * comparisons - that bit always becomes the high bit of + * bfloat->mantissa, and thus the exponent we're calculating here is + * the position of what will become the low bit in bfloat->mantissa: + * + * Note that this may be negative - we may be running off the low end + * of the key: we handle this later: + */ + high_bit = max(bch2_bkey_greatest_differing_bit(b, l, r), + min_t(unsigned, BKEY_MANTISSA_BITS, b->nr_key_bits) - 1); + exponent = high_bit - (BKEY_MANTISSA_BITS - 1); + + /* + * Then we calculate the actual shift value, from the start of the key + * (k->_data), to get the key bits starting at exponent: + */ +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + shift = (int) (b->format.key_u64s * 64 - b->nr_key_bits) + exponent; + + EBUG_ON(shift + BKEY_MANTISSA_BITS > b->format.key_u64s * 64); +#else + shift = high_bit_offset + + b->nr_key_bits - + exponent - + BKEY_MANTISSA_BITS; + + EBUG_ON(shift < KEY_PACKED_BITS_START); +#endif + EBUG_ON(shift < 0 || shift >= BFLOAT_FAILED); + + f->exponent = shift; + mantissa = bkey_mantissa(m, f, j); + + /* + * If we've got garbage bits, set them to all 1s - it's legal for the + * bfloat to compare larger than the original key, but not smaller: + */ + if (exponent < 0) + mantissa |= ~(~0U << -exponent); + + f->mantissa = mantissa; +} + +/* bytes remaining - only valid for last bset: */ +static unsigned __bset_tree_capacity(const struct btree *b, const struct bset_tree *t) +{ + bset_aux_tree_verify(b); + + return btree_aux_data_bytes(b) - t->aux_data_offset * sizeof(u64); +} + +static unsigned bset_ro_tree_capacity(const struct btree *b, const struct bset_tree *t) +{ + return __bset_tree_capacity(b, t) / + (sizeof(struct bkey_float) + sizeof(u8)); +} + +static unsigned bset_rw_tree_capacity(const struct btree *b, const struct bset_tree *t) +{ + return __bset_tree_capacity(b, t) / sizeof(struct rw_aux_tree); +} + +static noinline void __build_rw_aux_tree(struct btree *b, struct bset_tree *t) +{ + struct bkey_packed *k; + + t->size = 1; + t->extra = BSET_RW_AUX_TREE_VAL; + rw_aux_tree(b, t)[0].offset = + __btree_node_key_to_offset(b, btree_bkey_first(b, t)); + + bset_tree_for_each_key(b, t, k) { + if (t->size == bset_rw_tree_capacity(b, t)) + break; + + if ((void *) k - (void *) rw_aux_to_bkey(b, t, t->size - 1) > + L1_CACHE_BYTES) + rw_aux_tree_set(b, t, t->size++, k); + } +} + +static noinline void __build_ro_aux_tree(struct btree *b, struct bset_tree *t) +{ + struct bkey_packed *prev = NULL, *k = btree_bkey_first(b, t); + struct bkey_i min_key, max_key; + unsigned j, cacheline = 1; + + t->size = min(bkey_to_cacheline(b, t, btree_bkey_last(b, t)), + bset_ro_tree_capacity(b, t)); +retry: + if (t->size < 2) { + t->size = 0; + t->extra = BSET_NO_AUX_TREE_VAL; + return; + } + + t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1; + + /* First we figure out where the first key in each cacheline is */ + eytzinger1_for_each(j, t->size - 1) { + while (bkey_to_cacheline(b, t, k) < cacheline) + prev = k, k = bkey_p_next(k); + + if (k >= btree_bkey_last(b, t)) { + /* XXX: this path sucks */ + t->size--; + goto retry; + } + + ro_aux_tree_prev(b, t)[j] = prev->u64s; + bkey_float(b, t, j)->key_offset = + bkey_to_cacheline_offset(b, t, cacheline++, k); + + EBUG_ON(tree_to_prev_bkey(b, t, j) != prev); + EBUG_ON(tree_to_bkey(b, t, j) != k); + } + + while (k != btree_bkey_last(b, t)) + prev = k, k = bkey_p_next(k); + + if (!bkey_pack_pos(bkey_to_packed(&min_key), b->data->min_key, b)) { + bkey_init(&min_key.k); + min_key.k.p = b->data->min_key; + } + + if (!bkey_pack_pos(bkey_to_packed(&max_key), b->data->max_key, b)) { + bkey_init(&max_key.k); + max_key.k.p = b->data->max_key; + } + + /* Then we build the tree */ + eytzinger1_for_each(j, t->size - 1) + make_bfloat(b, t, j, + bkey_to_packed(&min_key), + bkey_to_packed(&max_key)); +} + +static void bset_alloc_tree(struct btree *b, struct bset_tree *t) +{ + struct bset_tree *i; + + for (i = b->set; i != t; i++) + BUG_ON(bset_has_rw_aux_tree(i)); + + bch2_bset_set_no_aux_tree(b, t); + + /* round up to next cacheline: */ + t->aux_data_offset = round_up(bset_aux_tree_buf_start(b, t), + SMP_CACHE_BYTES / sizeof(u64)); + + bset_aux_tree_verify(b); +} + +void bch2_bset_build_aux_tree(struct btree *b, struct bset_tree *t, + bool writeable) +{ + if (writeable + ? bset_has_rw_aux_tree(t) + : bset_has_ro_aux_tree(t)) + return; + + bset_alloc_tree(b, t); + + if (!__bset_tree_capacity(b, t)) + return; + + if (writeable) + __build_rw_aux_tree(b, t); + else + __build_ro_aux_tree(b, t); + + bset_aux_tree_verify(b); +} + +void bch2_bset_init_first(struct btree *b, struct bset *i) +{ + struct bset_tree *t; + + BUG_ON(b->nsets); + + memset(i, 0, sizeof(*i)); + get_random_bytes(&i->seq, sizeof(i->seq)); + SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN); + + t = &b->set[b->nsets++]; + set_btree_bset(b, t, i); +} + +void bch2_bset_init_next(struct bch_fs *c, struct btree *b, + struct btree_node_entry *bne) +{ + struct bset *i = &bne->keys; + struct bset_tree *t; + + BUG_ON(bset_byte_offset(b, bne) >= btree_bytes(c)); + BUG_ON((void *) bne < (void *) btree_bkey_last(b, bset_tree_last(b))); + BUG_ON(b->nsets >= MAX_BSETS); + + memset(i, 0, sizeof(*i)); + i->seq = btree_bset_first(b)->seq; + SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN); + + t = &b->set[b->nsets++]; + set_btree_bset(b, t, i); +} + +/* + * find _some_ key in the same bset as @k that precedes @k - not necessarily the + * immediate predecessor: + */ +static struct bkey_packed *__bkey_prev(struct btree *b, struct bset_tree *t, + struct bkey_packed *k) +{ + struct bkey_packed *p; + unsigned offset; + int j; + + EBUG_ON(k < btree_bkey_first(b, t) || + k > btree_bkey_last(b, t)); + + if (k == btree_bkey_first(b, t)) + return NULL; + + switch (bset_aux_tree_type(t)) { + case BSET_NO_AUX_TREE: + p = btree_bkey_first(b, t); + break; + case BSET_RO_AUX_TREE: + j = min_t(unsigned, t->size - 1, bkey_to_cacheline(b, t, k)); + + do { + p = j ? tree_to_bkey(b, t, + __inorder_to_eytzinger1(j--, + t->size - 1, t->extra)) + : btree_bkey_first(b, t); + } while (p >= k); + break; + case BSET_RW_AUX_TREE: + offset = __btree_node_key_to_offset(b, k); + j = rw_aux_tree_bsearch(b, t, offset); + p = j ? rw_aux_to_bkey(b, t, j - 1) + : btree_bkey_first(b, t); + break; + } + + return p; +} + +struct bkey_packed *bch2_bkey_prev_filter(struct btree *b, + struct bset_tree *t, + struct bkey_packed *k, + unsigned min_key_type) +{ + struct bkey_packed *p, *i, *ret = NULL, *orig_k = k; + + while ((p = __bkey_prev(b, t, k)) && !ret) { + for (i = p; i != k; i = bkey_p_next(i)) + if (i->type >= min_key_type) + ret = i; + + k = p; + } + + if (bch2_expensive_debug_checks) { + BUG_ON(ret >= orig_k); + + for (i = ret + ? bkey_p_next(ret) + : btree_bkey_first(b, t); + i != orig_k; + i = bkey_p_next(i)) + BUG_ON(i->type >= min_key_type); + } + + return ret; +} + +/* Insert */ + +static void bch2_bset_fix_lookup_table(struct btree *b, + struct bset_tree *t, + struct bkey_packed *_where, + unsigned clobber_u64s, + unsigned new_u64s) +{ + int shift = new_u64s - clobber_u64s; + unsigned l, j, where = __btree_node_key_to_offset(b, _where); + + EBUG_ON(bset_has_ro_aux_tree(t)); + + if (!bset_has_rw_aux_tree(t)) + return; + + /* returns first entry >= where */ + l = rw_aux_tree_bsearch(b, t, where); + + if (!l) /* never delete first entry */ + l++; + else if (l < t->size && + where < t->end_offset && + rw_aux_tree(b, t)[l].offset == where) + rw_aux_tree_set(b, t, l++, _where); + + /* l now > where */ + + for (j = l; + j < t->size && + rw_aux_tree(b, t)[j].offset < where + clobber_u64s; + j++) + ; + + if (j < t->size && + rw_aux_tree(b, t)[j].offset + shift == + rw_aux_tree(b, t)[l - 1].offset) + j++; + + memmove(&rw_aux_tree(b, t)[l], + &rw_aux_tree(b, t)[j], + (void *) &rw_aux_tree(b, t)[t->size] - + (void *) &rw_aux_tree(b, t)[j]); + t->size -= j - l; + + for (j = l; j < t->size; j++) + rw_aux_tree(b, t)[j].offset += shift; + + EBUG_ON(l < t->size && + rw_aux_tree(b, t)[l].offset == + rw_aux_tree(b, t)[l - 1].offset); + + if (t->size < bset_rw_tree_capacity(b, t) && + (l < t->size + ? rw_aux_tree(b, t)[l].offset + : t->end_offset) - + rw_aux_tree(b, t)[l - 1].offset > + L1_CACHE_BYTES / sizeof(u64)) { + struct bkey_packed *start = rw_aux_to_bkey(b, t, l - 1); + struct bkey_packed *end = l < t->size + ? rw_aux_to_bkey(b, t, l) + : btree_bkey_last(b, t); + struct bkey_packed *k = start; + + while (1) { + k = bkey_p_next(k); + if (k == end) + break; + + if ((void *) k - (void *) start >= L1_CACHE_BYTES) { + memmove(&rw_aux_tree(b, t)[l + 1], + &rw_aux_tree(b, t)[l], + (void *) &rw_aux_tree(b, t)[t->size] - + (void *) &rw_aux_tree(b, t)[l]); + t->size++; + rw_aux_tree_set(b, t, l, k); + break; + } + } + } + + bch2_bset_verify_rw_aux_tree(b, t); + bset_aux_tree_verify(b); +} + +void bch2_bset_insert(struct btree *b, + struct btree_node_iter *iter, + struct bkey_packed *where, + struct bkey_i *insert, + unsigned clobber_u64s) +{ + struct bkey_format *f = &b->format; + struct bset_tree *t = bset_tree_last(b); + struct bkey_packed packed, *src = bkey_to_packed(insert); + + bch2_bset_verify_rw_aux_tree(b, t); + bch2_verify_insert_pos(b, where, bkey_to_packed(insert), clobber_u64s); + + if (bch2_bkey_pack_key(&packed, &insert->k, f)) + src = &packed; + + if (!bkey_deleted(&insert->k)) + btree_keys_account_key_add(&b->nr, t - b->set, src); + + if (src->u64s != clobber_u64s) { + u64 *src_p = (u64 *) where->_data + clobber_u64s; + u64 *dst_p = (u64 *) where->_data + src->u64s; + + EBUG_ON((int) le16_to_cpu(bset(b, t)->u64s) < + (int) clobber_u64s - src->u64s); + + memmove_u64s(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p); + le16_add_cpu(&bset(b, t)->u64s, src->u64s - clobber_u64s); + set_btree_bset_end(b, t); + } + + memcpy_u64s_small(where, src, + bkeyp_key_u64s(f, src)); + memcpy_u64s(bkeyp_val(f, where), &insert->v, + bkeyp_val_u64s(f, src)); + + if (src->u64s != clobber_u64s) + bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, src->u64s); + + bch2_verify_btree_nr_keys(b); +} + +void bch2_bset_delete(struct btree *b, + struct bkey_packed *where, + unsigned clobber_u64s) +{ + struct bset_tree *t = bset_tree_last(b); + u64 *src_p = (u64 *) where->_data + clobber_u64s; + u64 *dst_p = where->_data; + + bch2_bset_verify_rw_aux_tree(b, t); + + EBUG_ON(le16_to_cpu(bset(b, t)->u64s) < clobber_u64s); + + memmove_u64s_down(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p); + le16_add_cpu(&bset(b, t)->u64s, -clobber_u64s); + set_btree_bset_end(b, t); + + bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, 0); +} + +/* Lookup */ + +__flatten +static struct bkey_packed *bset_search_write_set(const struct btree *b, + struct bset_tree *t, + struct bpos *search) +{ + unsigned l = 0, r = t->size; + + while (l + 1 != r) { + unsigned m = (l + r) >> 1; + + if (bpos_lt(rw_aux_tree(b, t)[m].k, *search)) + l = m; + else + r = m; + } + + return rw_aux_to_bkey(b, t, l); +} + +static inline void prefetch_four_cachelines(void *p) +{ +#ifdef CONFIG_X86_64 + asm("prefetcht0 (-127 + 64 * 0)(%0);" + "prefetcht0 (-127 + 64 * 1)(%0);" + "prefetcht0 (-127 + 64 * 2)(%0);" + "prefetcht0 (-127 + 64 * 3)(%0);" + : + : "r" (p + 127)); +#else + prefetch(p + L1_CACHE_BYTES * 0); + prefetch(p + L1_CACHE_BYTES * 1); + prefetch(p + L1_CACHE_BYTES * 2); + prefetch(p + L1_CACHE_BYTES * 3); +#endif +} + +static inline bool bkey_mantissa_bits_dropped(const struct btree *b, + const struct bkey_float *f, + unsigned idx) +{ +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + unsigned key_bits_start = b->format.key_u64s * 64 - b->nr_key_bits; + + return f->exponent > key_bits_start; +#else + unsigned key_bits_end = high_bit_offset + b->nr_key_bits; + + return f->exponent + BKEY_MANTISSA_BITS < key_bits_end; +#endif +} + +__flatten +static struct bkey_packed *bset_search_tree(const struct btree *b, + const struct bset_tree *t, + const struct bpos *search, + const struct bkey_packed *packed_search) +{ + struct ro_aux_tree *base = ro_aux_tree_base(b, t); + struct bkey_float *f; + struct bkey_packed *k; + unsigned inorder, n = 1, l, r; + int cmp; + + do { + if (likely(n << 4 < t->size)) + prefetch(&base->f[n << 4]); + + f = &base->f[n]; + if (unlikely(f->exponent >= BFLOAT_FAILED)) + goto slowpath; + + l = f->mantissa; + r = bkey_mantissa(packed_search, f, n); + + if (unlikely(l == r) && bkey_mantissa_bits_dropped(b, f, n)) + goto slowpath; + + n = n * 2 + (l < r); + continue; +slowpath: + k = tree_to_bkey(b, t, n); + cmp = bkey_cmp_p_or_unp(b, k, packed_search, search); + if (!cmp) + return k; + + n = n * 2 + (cmp < 0); + } while (n < t->size); + + inorder = __eytzinger1_to_inorder(n >> 1, t->size - 1, t->extra); + + /* + * n would have been the node we recursed to - the low bit tells us if + * we recursed left or recursed right. + */ + if (likely(!(n & 1))) { + --inorder; + if (unlikely(!inorder)) + return btree_bkey_first(b, t); + + f = &base->f[eytzinger1_prev(n >> 1, t->size - 1)]; + } + + return cacheline_to_bkey(b, t, inorder, f->key_offset); +} + +static __always_inline __flatten +struct bkey_packed *__bch2_bset_search(struct btree *b, + struct bset_tree *t, + struct bpos *search, + const struct bkey_packed *lossy_packed_search) +{ + + /* + * First, we search for a cacheline, then lastly we do a linear search + * within that cacheline. + * + * To search for the cacheline, there's three different possibilities: + * * The set is too small to have a search tree, so we just do a linear + * search over the whole set. + * * The set is the one we're currently inserting into; keeping a full + * auxiliary search tree up to date would be too expensive, so we + * use a much simpler lookup table to do a binary search - + * bset_search_write_set(). + * * Or we use the auxiliary search tree we constructed earlier - + * bset_search_tree() + */ + + switch (bset_aux_tree_type(t)) { + case BSET_NO_AUX_TREE: + return btree_bkey_first(b, t); + case BSET_RW_AUX_TREE: + return bset_search_write_set(b, t, search); + case BSET_RO_AUX_TREE: + return bset_search_tree(b, t, search, lossy_packed_search); + default: + BUG(); + } +} + +static __always_inline __flatten +struct bkey_packed *bch2_bset_search_linear(struct btree *b, + struct bset_tree *t, + struct bpos *search, + struct bkey_packed *packed_search, + const struct bkey_packed *lossy_packed_search, + struct bkey_packed *m) +{ + if (lossy_packed_search) + while (m != btree_bkey_last(b, t) && + bkey_iter_cmp_p_or_unp(b, m, + lossy_packed_search, search) < 0) + m = bkey_p_next(m); + + if (!packed_search) + while (m != btree_bkey_last(b, t) && + bkey_iter_pos_cmp(b, m, search) < 0) + m = bkey_p_next(m); + + if (bch2_expensive_debug_checks) { + struct bkey_packed *prev = bch2_bkey_prev_all(b, t, m); + + BUG_ON(prev && + bkey_iter_cmp_p_or_unp(b, prev, + packed_search, search) >= 0); + } + + return m; +} + +/* Btree node iterator */ + +static inline void __bch2_btree_node_iter_push(struct btree_node_iter *iter, + struct btree *b, + const struct bkey_packed *k, + const struct bkey_packed *end) +{ + if (k != end) { + struct btree_node_iter_set *pos; + + btree_node_iter_for_each(iter, pos) + ; + + BUG_ON(pos >= iter->data + ARRAY_SIZE(iter->data)); + *pos = (struct btree_node_iter_set) { + __btree_node_key_to_offset(b, k), + __btree_node_key_to_offset(b, end) + }; + } +} + +void bch2_btree_node_iter_push(struct btree_node_iter *iter, + struct btree *b, + const struct bkey_packed *k, + const struct bkey_packed *end) +{ + __bch2_btree_node_iter_push(iter, b, k, end); + bch2_btree_node_iter_sort(iter, b); +} + +noinline __flatten __cold +static void btree_node_iter_init_pack_failed(struct btree_node_iter *iter, + struct btree *b, struct bpos *search) +{ + struct bkey_packed *k; + + trace_bkey_pack_pos_fail(search); + + bch2_btree_node_iter_init_from_start(iter, b); + + while ((k = bch2_btree_node_iter_peek(iter, b)) && + bkey_iter_pos_cmp(b, k, search) < 0) + bch2_btree_node_iter_advance(iter, b); +} + +/** + * bch2_btree_node_iter_init - initialize a btree node iterator, starting from a + * given position + * + * @iter: iterator to initialize + * @b: btree node to search + * @search: search key + * + * Main entry point to the lookup code for individual btree nodes: + * + * NOTE: + * + * When you don't filter out deleted keys, btree nodes _do_ contain duplicate + * keys. This doesn't matter for most code, but it does matter for lookups. + * + * Some adjacent keys with a string of equal keys: + * i j k k k k l m + * + * If you search for k, the lookup code isn't guaranteed to return you any + * specific k. The lookup code is conceptually doing a binary search and + * iterating backwards is very expensive so if the pivot happens to land at the + * last k that's what you'll get. + * + * This works out ok, but it's something to be aware of: + * + * - For non extents, we guarantee that the live key comes last - see + * btree_node_iter_cmp(), keys_out_of_order(). So the duplicates you don't + * see will only be deleted keys you don't care about. + * + * - For extents, deleted keys sort last (see the comment at the top of this + * file). But when you're searching for extents, you actually want the first + * key strictly greater than your search key - an extent that compares equal + * to the search key is going to have 0 sectors after the search key. + * + * But this does mean that we can't just search for + * bpos_successor(start_of_range) to get the first extent that overlaps with + * the range we want - if we're unlucky and there's an extent that ends + * exactly where we searched, then there could be a deleted key at the same + * position and we'd get that when we search instead of the preceding extent + * we needed. + * + * So we've got to search for start_of_range, then after the lookup iterate + * past any extents that compare equal to the position we searched for. + */ +__flatten +void bch2_btree_node_iter_init(struct btree_node_iter *iter, + struct btree *b, struct bpos *search) +{ + struct bkey_packed p, *packed_search = NULL; + struct btree_node_iter_set *pos = iter->data; + struct bkey_packed *k[MAX_BSETS]; + unsigned i; + + EBUG_ON(bpos_lt(*search, b->data->min_key)); + EBUG_ON(bpos_gt(*search, b->data->max_key)); + bset_aux_tree_verify(b); + + memset(iter, 0, sizeof(*iter)); + + switch (bch2_bkey_pack_pos_lossy(&p, *search, b)) { + case BKEY_PACK_POS_EXACT: + packed_search = &p; + break; + case BKEY_PACK_POS_SMALLER: + packed_search = NULL; + break; + case BKEY_PACK_POS_FAIL: + btree_node_iter_init_pack_failed(iter, b, search); + return; + } + + for (i = 0; i < b->nsets; i++) { + k[i] = __bch2_bset_search(b, b->set + i, search, &p); + prefetch_four_cachelines(k[i]); + } + + for (i = 0; i < b->nsets; i++) { + struct bset_tree *t = b->set + i; + struct bkey_packed *end = btree_bkey_last(b, t); + + k[i] = bch2_bset_search_linear(b, t, search, + packed_search, &p, k[i]); + if (k[i] != end) + *pos++ = (struct btree_node_iter_set) { + __btree_node_key_to_offset(b, k[i]), + __btree_node_key_to_offset(b, end) + }; + } + + bch2_btree_node_iter_sort(iter, b); +} + +void bch2_btree_node_iter_init_from_start(struct btree_node_iter *iter, + struct btree *b) +{ + struct bset_tree *t; + + memset(iter, 0, sizeof(*iter)); + + for_each_bset(b, t) + __bch2_btree_node_iter_push(iter, b, + btree_bkey_first(b, t), + btree_bkey_last(b, t)); + bch2_btree_node_iter_sort(iter, b); +} + +struct bkey_packed *bch2_btree_node_iter_bset_pos(struct btree_node_iter *iter, + struct btree *b, + struct bset_tree *t) +{ + struct btree_node_iter_set *set; + + btree_node_iter_for_each(iter, set) + if (set->end == t->end_offset) + return __btree_node_offset_to_key(b, set->k); + + return btree_bkey_last(b, t); +} + +static inline bool btree_node_iter_sort_two(struct btree_node_iter *iter, + struct btree *b, + unsigned first) +{ + bool ret; + + if ((ret = (btree_node_iter_cmp(b, + iter->data[first], + iter->data[first + 1]) > 0))) + swap(iter->data[first], iter->data[first + 1]); + return ret; +} + +void bch2_btree_node_iter_sort(struct btree_node_iter *iter, + struct btree *b) +{ + /* unrolled bubble sort: */ + + if (!__btree_node_iter_set_end(iter, 2)) { + btree_node_iter_sort_two(iter, b, 0); + btree_node_iter_sort_two(iter, b, 1); + } + + if (!__btree_node_iter_set_end(iter, 1)) + btree_node_iter_sort_two(iter, b, 0); +} + +void bch2_btree_node_iter_set_drop(struct btree_node_iter *iter, + struct btree_node_iter_set *set) +{ + struct btree_node_iter_set *last = + iter->data + ARRAY_SIZE(iter->data) - 1; + + memmove(&set[0], &set[1], (void *) last - (void *) set); + *last = (struct btree_node_iter_set) { 0, 0 }; +} + +static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *iter, + struct btree *b) +{ + iter->data->k += __bch2_btree_node_iter_peek_all(iter, b)->u64s; + + EBUG_ON(iter->data->k > iter->data->end); + + if (unlikely(__btree_node_iter_set_end(iter, 0))) { + /* avoid an expensive memmove call: */ + iter->data[0] = iter->data[1]; + iter->data[1] = iter->data[2]; + iter->data[2] = (struct btree_node_iter_set) { 0, 0 }; + return; + } + + if (__btree_node_iter_set_end(iter, 1)) + return; + + if (!btree_node_iter_sort_two(iter, b, 0)) + return; + + if (__btree_node_iter_set_end(iter, 2)) + return; + + btree_node_iter_sort_two(iter, b, 1); +} + +void bch2_btree_node_iter_advance(struct btree_node_iter *iter, + struct btree *b) +{ + if (bch2_expensive_debug_checks) { + bch2_btree_node_iter_verify(iter, b); + bch2_btree_node_iter_next_check(iter, b); + } + + __bch2_btree_node_iter_advance(iter, b); +} + +/* + * Expensive: + */ +struct bkey_packed *bch2_btree_node_iter_prev_all(struct btree_node_iter *iter, + struct btree *b) +{ + struct bkey_packed *k, *prev = NULL; + struct btree_node_iter_set *set; + struct bset_tree *t; + unsigned end = 0; + + if (bch2_expensive_debug_checks) + bch2_btree_node_iter_verify(iter, b); + + for_each_bset(b, t) { + k = bch2_bkey_prev_all(b, t, + bch2_btree_node_iter_bset_pos(iter, b, t)); + if (k && + (!prev || bkey_iter_cmp(b, k, prev) > 0)) { + prev = k; + end = t->end_offset; + } + } + + if (!prev) + return NULL; + + /* + * We're manually memmoving instead of just calling sort() to ensure the + * prev we picked ends up in slot 0 - sort won't necessarily put it + * there because of duplicate deleted keys: + */ + btree_node_iter_for_each(iter, set) + if (set->end == end) + goto found; + + BUG_ON(set != &iter->data[__btree_node_iter_used(iter)]); +found: + BUG_ON(set >= iter->data + ARRAY_SIZE(iter->data)); + + memmove(&iter->data[1], + &iter->data[0], + (void *) set - (void *) &iter->data[0]); + + iter->data[0].k = __btree_node_key_to_offset(b, prev); + iter->data[0].end = end; + + if (bch2_expensive_debug_checks) + bch2_btree_node_iter_verify(iter, b); + return prev; +} + +struct bkey_packed *bch2_btree_node_iter_prev(struct btree_node_iter *iter, + struct btree *b) +{ + struct bkey_packed *prev; + + do { + prev = bch2_btree_node_iter_prev_all(iter, b); + } while (prev && bkey_deleted(prev)); + + return prev; +} + +struct bkey_s_c bch2_btree_node_iter_peek_unpack(struct btree_node_iter *iter, + struct btree *b, + struct bkey *u) +{ + struct bkey_packed *k = bch2_btree_node_iter_peek(iter, b); + + return k ? bkey_disassemble(b, k, u) : bkey_s_c_null; +} + +/* Mergesort */ + +void bch2_btree_keys_stats(const struct btree *b, struct bset_stats *stats) +{ + const struct bset_tree *t; + + for_each_bset(b, t) { + enum bset_aux_tree_type type = bset_aux_tree_type(t); + size_t j; + + stats->sets[type].nr++; + stats->sets[type].bytes += le16_to_cpu(bset(b, t)->u64s) * + sizeof(u64); + + if (bset_has_ro_aux_tree(t)) { + stats->floats += t->size - 1; + + for (j = 1; j < t->size; j++) + stats->failed += + bkey_float(b, t, j)->exponent == + BFLOAT_FAILED; + } + } +} + +void bch2_bfloat_to_text(struct printbuf *out, struct btree *b, + struct bkey_packed *k) +{ + struct bset_tree *t = bch2_bkey_to_bset(b, k); + struct bkey uk; + unsigned j, inorder; + + if (!bset_has_ro_aux_tree(t)) + return; + + inorder = bkey_to_cacheline(b, t, k); + if (!inorder || inorder >= t->size) + return; + + j = __inorder_to_eytzinger1(inorder, t->size - 1, t->extra); + if (k != tree_to_bkey(b, t, j)) + return; + + switch (bkey_float(b, t, j)->exponent) { + case BFLOAT_FAILED: + uk = bkey_unpack_key(b, k); + prt_printf(out, + " failed unpacked at depth %u\n" + "\t", + ilog2(j)); + bch2_bpos_to_text(out, uk.p); + prt_printf(out, "\n"); + break; + } +} |