// 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 <linux/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);
if (!_k->u64s) {
printk(KERN_ERR "block %u key %5zu - u64s 0? aieee!\n", set,
_k->_data - i->_data);
break;
}
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)
{
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);
}
struct btree_nr_keys bch2_btree_node_count_keys(struct btree *b)
{
struct bkey_packed *k;
struct btree_nr_keys nr = {};
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);
return nr;
}
#ifdef CONFIG_BCACHEFS_DEBUG
void __bch2_verify_btree_nr_keys(struct btree *b)
{
struct btree_nr_keys nr = bch2_btree_node_count_keys(b);
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;
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) {
BUG_ON(set->k < btree_bkey_first_offset(t) ||
set->k >= t->end_offset);
goto found;
}
BUG();
found:
do {} while (0);
}
/* 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
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), 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 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(struct btree *b)
{
#ifdef CONFIG_BCACHEFS_DEBUG
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 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)
{
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_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);
/*
* 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(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(struct btree *b, const struct bset_tree *t)
{
return __bset_tree_capacity(b, t) / sizeof(struct bkey_float);
}
static unsigned bset_rw_tree_capacity(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 *k = btree_bkey_first(b, t);
struct bkey_i min_key, max_key;
unsigned 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 = eytzinger1_extra(t->size - 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)
k = bkey_p_next(k);
if (k >= btree_bkey_last(b, t)) {
/* XXX: this path sucks */
t->size--;
goto retry;
}
bkey_float(b, t, j)->key_offset =
bkey_to_cacheline_offset(b, t, cacheline++, k);
EBUG_ON(tree_to_bkey(b, t, j) != 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 btree *b, struct btree_node_entry *bne)
{
struct bset *i = &bne->keys;
struct bset_tree *t;
BUG_ON(bset_byte_offset(b, bne) >= btree_buf_bytes(b));
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 rw_aux_tree_insert_entry(struct btree *b,
struct bset_tree *t,
unsigned idx)
{
EBUG_ON(!idx || idx > t->size);
struct bkey_packed *start = rw_aux_to_bkey(b, t, idx - 1);
struct bkey_packed *end = idx < t->size
? rw_aux_to_bkey(b, t, idx)
: btree_bkey_last(b, t);
if (t->size < bset_rw_tree_capacity(b, t) &&
(void *) end - (void *) start > L1_CACHE_BYTES) {
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)[idx + 1],
&rw_aux_tree(b, t)[idx],
(void *) &rw_aux_tree(b, t)[t->size] -
(void *) &rw_aux_tree(b, t)[idx]);
t->size++;
rw_aux_tree_set(b, t, idx, k);
break;
}
}
}
}
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 idx, 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;
if (where > rw_aux_tree(b, t)[t->size - 1].offset) {
rw_aux_tree_insert_entry(b, t, t->size);
goto verify;
}
/* returns first entry >= where */
idx = rw_aux_tree_bsearch(b, t, where);
if (rw_aux_tree(b, t)[idx].offset == where) {
if (!idx) { /* never delete first entry */
idx++;
} else if (where < t->end_offset) {
rw_aux_tree_set(b, t, idx++, _where);
} else {
EBUG_ON(where != t->end_offset);
rw_aux_tree_insert_entry(b, t, --t->size);
goto verify;
}
}
EBUG_ON(idx < t->size && rw_aux_tree(b, t)[idx].offset <= where);
if (idx < t->size &&
rw_aux_tree(b, t)[idx].offset + shift ==
rw_aux_tree(b, t)[idx - 1].offset) {
memmove(&rw_aux_tree(b, t)[idx],
&rw_aux_tree(b, t)[idx + 1],
(void *) &rw_aux_tree(b, t)[t->size] -
(void *) &rw_aux_tree(b, t)[idx + 1]);
t->size -= 1;
}
for (j = idx; j < t->size; j++)
rw_aux_tree(b, t)[j].offset += shift;
EBUG_ON(idx < t->size &&
rw_aux_tree(b, t)[idx].offset ==
rw_aux_tree(b, t)[idx - 1].offset);
rw_aux_tree_insert_entry(b, t, idx);
verify:
bch2_bset_verify_rw_aux_tree(b, t);
bset_aux_tree_verify(b);
}
void bch2_bset_insert(struct btree *b,
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)
{
#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);
if (unlikely(l == r) && bkey_mantissa_bits_dropped(b, f))
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)
{
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;
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)
{
for_each_bset_c(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;
}
}
Codebase Browser
linux