thin-provisioning-tools/btree.tcc

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#include "btree.h"
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#include "transaction_manager.h"
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#include <iostream>
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using namespace btree_detail;
using namespace persistent_data;
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using namespace std;
//----------------------------------------------------------------
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template <typename ValueTraits, uint32_t BlockSize>
node_ref<ValueTraits, BlockSize>::node_ref(disk_node *raw)
: raw_(raw)
{
}
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template <typename ValueTraits, uint32_t BlockSize>
btree_detail::node_type
node_ref<ValueTraits, BlockSize>::get_type() const
{
uint32_t flags = to_cpu<uint32_t>(raw_->header.flags);
if (flags & INTERNAL_NODE)
return INTERNAL;
else if (flags & LEAF_NODE)
return LEAF;
else
throw runtime_error("unknow node type");
}
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template <typename ValueTraits, uint32_t BlockSize>
void
node_ref<ValueTraits, BlockSize>::set_type(node_type t)
{
uint32_t flags = to_cpu<uint32_t>(raw_->header.flags);
switch (t) {
case INTERNAL:
flags |= INTERNAL_NODE;
break;
case LEAF:
flags |= LEAF_NODE;
break;
}
raw_->header.flags = to_disk<__le32>(flags);
}
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template <typename ValueTraits, uint32_t BlockSize>
unsigned
node_ref<ValueTraits, BlockSize>::get_nr_entries() const
{
return to_cpu<uint32_t>(raw_->header.nr_entries);
}
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template <typename ValueTraits, uint32_t BlockSize>
void
node_ref<ValueTraits, BlockSize>::set_nr_entries(unsigned n)
{
raw_->header.nr_entries = to_disk<__le32>(n);
}
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template <typename ValueTraits, uint32_t BlockSize>
unsigned
node_ref<ValueTraits, BlockSize>::get_max_entries() const
{
return to_cpu<uint32_t>(raw_->header.max_entries);
}
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template <typename ValueTraits, uint32_t BlockSize>
void
node_ref<ValueTraits, BlockSize>::set_max_entries(unsigned n)
{
raw_->header.max_entries = to_disk<__le32>(n);
}
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template <typename ValueTraits, uint32_t BlockSize>
void
node_ref<ValueTraits, BlockSize>::set_max_entries()
{
set_max_entries(calc_max_entries());
}
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template <typename ValueTraits, uint32_t BlockSize>
uint64_t
node_ref<ValueTraits, BlockSize>::key_at(unsigned i) const
{
return to_cpu<uint64_t>(raw_->keys[i]);
}
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template <typename ValueTraits, uint32_t BlockSize>
void
node_ref<ValueTraits, BlockSize>::set_key(unsigned i, uint64_t k)
{
raw_->keys[i] = to_disk<__le64>(k);
}
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template <typename ValueTraits, uint32_t BlockSize>
typename ValueTraits::value_type
node_ref<ValueTraits, BlockSize>::value_at(unsigned i) const
{
// We have to copy because of alignment issues.
typename ValueTraits::disk_type d;
::memcpy(&d, value_ptr(i), sizeof(d));
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typename ValueTraits::value_type v;
ValueTraits::unpack(d, v);
return v;
}
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template <typename ValueTraits, uint32_t BlockSize>
void
node_ref<ValueTraits, BlockSize>::set_value(unsigned i,
typename ValueTraits::value_type const &v)
{
typename ValueTraits::disk_type d;
ValueTraits::pack(v, d);
::memcpy(value_ptr(i), &d, sizeof(d));
}
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template <typename ValueTraits, uint32_t BlockSize>
void
node_ref<ValueTraits, BlockSize>::insert_at(unsigned i,
uint64_t key,
typename ValueTraits::value_type const &v)
{
unsigned n = get_nr_entries();
if ((n + 1) > get_max_entries())
throw runtime_error("too many entries");
set_nr_entries(n + 1);
::memmove(key_ptr(i + 1), key_ptr(i), sizeof(uint64_t));
::memmove(value_ptr(i + 1), value_ptr(i), sizeof(typename ValueTraits::disk_type));
overwrite_at(i, key, v);
}
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template <typename ValueTraits, uint32_t BlockSize>
void
node_ref<ValueTraits, BlockSize>::overwrite_at(unsigned i,
uint64_t key,
typename ValueTraits::value_type const &v)
{
set_key(i, key);
set_value(i, v);
}
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template <typename ValueTraits, uint32_t BlockSize>
void
node_ref<ValueTraits, BlockSize>::copy_entries(node_ref const &rhs,
unsigned begin,
unsigned end)
{
unsigned count = end - begin;
unsigned n = get_nr_entries();
if ((n + count) > get_max_entries())
throw runtime_error("too many entries");
set_nr_entries(n + count);
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::memcpy(key_ptr(n), rhs.key_ptr(begin), sizeof(uint64_t) * count);
::memcpy(value_ptr(n), rhs.value_ptr(begin), sizeof(typename ValueTraits::disk_type) * count);
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}
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template <typename ValueTraits, uint32_t BlockSize>
int
node_ref<ValueTraits, BlockSize>::bsearch(uint64_t key,
int want_hi) const
{
int lo = -1, hi = get_nr_entries();
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while(hi - lo > 1) {
int mid = lo + ((hi - lo) / 2);
uint64_t mid_key = key_at(mid);
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if (mid_key == key)
return mid;
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if (mid_key < key)
lo = mid;
else
hi = mid;
}
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return want_hi ? hi : lo;
}
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template <typename ValueTraits, uint32_t BlockSize>
optional<unsigned>
node_ref<ValueTraits, BlockSize>::exact_search(uint64_t key) const
{
int i = bsearch(key, 0);
if (i < 0 || static_cast<unsigned>(i) >= get_nr_entries())
return optional<unsigned>();
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return optional<unsigned>(i);
}
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template <typename ValueTraits, uint32_t BlockSize>
int
node_ref<ValueTraits, BlockSize>::lower_bound(uint64_t key) const
{
return bsearch(key, 0);
}
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template <typename ValueTraits, uint32_t BlockSize>
unsigned
node_ref<ValueTraits, BlockSize>::calc_max_entries(void)
{
uint32_t total;
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// key + value
size_t elt_size = sizeof(uint64_t) + sizeof(typename ValueTraits::disk_type);
total = (BlockSize - sizeof(struct node_header)) / elt_size;
return (total / 3) * 3; // rounds down
}
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template <typename ValueTraits, uint32_t BlockSize>
void *
node_ref<ValueTraits, BlockSize>::key_ptr(unsigned i) const
{
return raw_->keys + i;
}
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template <typename ValueTraits, uint32_t BlockSize>
void *
node_ref<ValueTraits, BlockSize>::value_ptr(unsigned i) const
{
void *value_base = &raw_->keys[to_cpu<uint32_t>(raw_->header.max_entries)];
return static_cast<unsigned char *>(value_base) +
sizeof(typename ValueTraits::disk_type) * i;
}
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template <typename ValueTraits, uint32_t BlockSize>
template <typename RefCounter>
void
node_ref<ValueTraits, BlockSize>::inc_children(RefCounter &rc)
{
unsigned nr_entries = get_nr_entries();
for (unsigned i = 0; i < nr_entries; i++) {
typename ValueTraits::value_type v;
typename ValueTraits::disk_type d;
::memcpy(&d, value_ptr(i), sizeof(d));
ValueTraits::unpack(d, v);
rc.inc(v);
}
}
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//----------------------------------------------------------------
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
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btree<Levels, ValueTraits, BlockSize>::
btree(typename transaction_manager<BlockSize>::ptr tm,
typename ValueTraits::ref_counter rc)
: tm_(tm),
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destroy_(false),
rc_(rc)
{
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using namespace btree_detail;
write_ref root = tm_->new_block();
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auto n = to_node<ValueTraits, BlockSize>(root);
n.set_type(btree_detail::LEAF);
n.set_nr_entries(0);
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n.set_max_entries();
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root_ = root.get_location();
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
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btree<Levels, ValueTraits, BlockSize>::
btree(typename transaction_manager<BlockSize>::ptr tm,
block_address root,
typename ValueTraits::ref_counter rc)
: tm_(tm),
destroy_(false),
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root_(root),
rc_(rc)
{
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
btree<Levels, ValueTraits, BlockSize>::~btree()
{
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
typename btree<Levels, ValueTraits, BlockSize>::maybe_value
btree<Levels, ValueTraits, BlockSize>::lookup(key const &key) const
{
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using namespace btree_detail;
ro_spine<BlockSize> spine(tm_);
block_address root = root_;
for (unsigned level = 0; level < Levels - 1; ++level) {
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optional<block_address> mroot =
lookup_raw<uint64_traits, BlockSize>(spine, root, key[level]);
if (!mroot)
return maybe_value();
root = *mroot;
}
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return lookup_raw<ValueTraits, BlockSize>(spine, root, key[Levels - 1]);
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
typename btree<Levels, ValueTraits, BlockSize>::maybe_pair
btree<Levels, ValueTraits, BlockSize>::lookup_le(key const &key) const
{
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using namespace btree_detail;
return maybe_pair();
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
typename btree<Levels, ValueTraits, BlockSize>::maybe_pair
btree<Levels, ValueTraits, BlockSize>::lookup_ge(key const &key) const
{
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using namespace btree_detail;
return maybe_pair();
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
void
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btree<Levels, ValueTraits, BlockSize>::
insert(key const &key,
typename ValueTraits::value_type const &value)
{
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using namespace btree_detail;
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block_address block = root_;
int index = 0; // FIXME: ???
shadow_spine<BlockSize> spine(tm_);
for (unsigned level = 0; level < Levels - 1; ++level) {
bool need_insert = insert_location<uint64_traits>(spine, block, key[level], &index);
auto n = spine.template get_node<uint64_traits>();
if (need_insert) {
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btree<Levels - 1, ValueTraits, BlockSize> new_tree(tm_, rc_);
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n.insert_at(index, key[level], new_tree.get_root());
}
block = n.value_at(index);
}
bool need_insert = insert_location<ValueTraits>(spine, block, key[Levels - 1], &index);
auto n = spine.template get_node<ValueTraits>();
if (need_insert)
n.insert_at(index, key[Levels - 1], value);
else
// FIXME: check if we're overwriting with the same value.
n.set_value(index, value);
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
void
btree<Levels, ValueTraits, BlockSize>::remove(key const &key)
{
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using namespace btree_detail;
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
block_address
btree<Levels, ValueTraits, BlockSize>::get_root() const
{
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return root_;
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
void
btree<Levels, ValueTraits, BlockSize>::set_root(block_address root)
{
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using namespace btree_detail;
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root_ = root;
}
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
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typename btree<Levels, ValueTraits, BlockSize>::ptr
btree<Levels, ValueTraits, BlockSize>::clone() const
{
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using namespace btree_detail;
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ro_spine<BlockSize> spine(tm_);
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spine.step(root_);
auto new_root = tm_->new_block();
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auto o = spine.template get_node<uint64_traits>();
if (o.get_type() == INTERNAL) {
auto n = to_node<uint64_traits, BlockSize>(new_root);
::memcpy(n.raw(), o.raw(), BlockSize);
typename uint64_traits::ref_counter rc(internal_rc_);
n.inc_children(rc);
} else {
auto n = to_node<ValueTraits, BlockSize>(new_root);
::memcpy(n.raw(), o.raw(), BlockSize);
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typename ValueTraits::ref_counter rc(rc_);
n.inc_children(rc);
}
return btree<Levels, ValueTraits, BlockSize>::ptr(
new btree<Levels, ValueTraits, BlockSize>(
tm_, new_root.get_location(), rc_));
}
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#if 0
template <unsigned Levels, typename ValueTraits, uint32_t BlockSize>
void
btree<Levels, ValueTraits, BlockSize>::destroy()
{
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using namespace btree_detail;
}
#endif
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template <unsigned Levels, typename _, uint32_t BlockSize>
template <typename ValueTraits>
void
btree<Levels, _, BlockSize>::
split_node(btree_detail::shadow_spine<BlockSize> &spine,
block_address parent_index,
uint64_t key,
bool top)
{
auto n = spine.template get_node<ValueTraits>();
if (n.get_nr_entries() == n.get_max_entries()) {
if (top)
split_beneath<ValueTraits>(spine, key);
else
split_sibling<ValueTraits>(spine, parent_index, key);
}
}
template <unsigned Levels, typename _, uint32_t BlockSize>
template <typename ValueTraits>
void
btree<Levels, _, BlockSize>::
split_beneath(btree_detail::shadow_spine<BlockSize> &spine,
uint64_t key)
{
using namespace btree_detail;
node_type type;
unsigned nr_left, nr_right;
auto left = tm_->new_block();
auto l = to_node<ValueTraits, BlockSize>(left);
l.set_nr_entries(0);
l.set_max_entries();
auto right = tm_->new_block();
auto r = to_node<ValueTraits, BlockSize>(right);
r.set_nr_entries(0);
r.set_max_entries();
{
auto p = spine.template get_node<ValueTraits>();
nr_left = p.get_nr_entries() / 2;
nr_right = p.get_nr_entries() - nr_left;
type = p.get_type();
l.set_type(type);
l.copy_entries(p, 0, nr_left);
r.set_type(type);
r.copy_entries(p, nr_left, nr_left + nr_right);
}
{
// The parent may have changed value type, so we re-get it.
auto p = spine.template get_node<uint64_traits>();
p.set_type(btree_detail::INTERNAL);
p.set_nr_entries(2);
p.overwrite_at(0, l.key_at(0), left.get_location());
p.overwrite_at(1, r.key_at(0), right.get_location());
}
if (key < r.key_at(0))
spine.step(left);
else
spine.step(right);
}
template <unsigned Levels, typename _, uint32_t BlockSize>
template <typename ValueTraits>
void
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btree<Levels, _, BlockSize>::
split_sibling(btree_detail::shadow_spine<BlockSize> &spine,
block_address parent_index,
uint64_t key)
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{
using namespace btree_detail;
auto l = spine.template get_node<ValueTraits>();
auto left = spine.get_block();
auto right = tm_->new_block();
auto r = to_node<ValueTraits, BlockSize>(right);
unsigned nr_left = l.get_nr_entries() / 2;
unsigned nr_right = l.get_nr_entries() - nr_left;
r.set_nr_entries(0);
r.set_type(l.get_type());
r.set_max_entries(l.get_max_entries());
r.copy_entries(l, nr_left, nr_left + nr_right);
l.set_nr_entries(nr_left);
auto p = spine.get_parent();
p.overwrite_at(parent_index, l.key_at(0), left);
p.insert_at(parent_index + 1, r.key_at(0), right.get_location());
spine.pop();
if (key < r.key_at(0))
spine.step(left);
else
spine.step(right);
}
// Returns true if we need a new insertion, rather than overwrite.
template <unsigned Levels, typename _, uint32_t BlockSize>
template <typename ValueTraits>
bool
btree<Levels, _, BlockSize>::
insert_location(btree_detail::shadow_spine<BlockSize> &spine,
block_address block,
uint64_t key,
int *index)
{
using namespace btree_detail;
bool top = true; // this isn't the same as spine.has_parent()
int i = *index;
bool inc = false;
for (;;) {
inc = spine.step(block);
#if 0
if (inc)
inc_children<ValueTraits>();
#endif
// patch up the parent to point to the new shadow
if (spine.has_parent()) {
auto p = spine.get_parent();
p.set_value(i, spine.get_block());
}
auto internal = spine.template get_node<uint64_traits>();
// Split the node if we're full
if (internal.get_type() == INTERNAL)
split_node<uint64_traits>(spine, i, key, top);
else
split_node<ValueTraits>(spine, i, key, top);
internal = spine.template get_node<uint64_traits>();
i = internal.lower_bound(key);
if (internal.get_type() == btree_detail::LEAF)
break;
if (i < 0) {
internal.set_key(0, key);
i = 0;
}
block = internal.value_at(i);
top = false;
}
auto leaf = spine.template get_node<ValueTraits>();
// FIXME: gross
if (i < 0 || leaf.key_at(i) != key)
i++;
// do decrement the old value if it already exists
// FIXME: I'm not sure about this, I don't understand the |inc| reference
if (leaf.key_at(i) == key && inc) {
// dec old entry
}
*index = i;
return ((static_cast<unsigned>(i) >= leaf.get_nr_entries()) ||
(leaf.key_at(i) != key));
}
//----------------------------------------------------------------