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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:nil -*-
// vim: ts=8 sw=2 smarttab
#include <algorithm>
#include <cstdint>
#include <type_traits>
#include <variant>
#include "common/hobject.h"
#include "crimson/common/layout.h"
#include "crimson/os/seastore/onode.h"
#include "crimson/os/seastore/seastore_types.h"
#include "onode_delta.h"
namespace asci = absl::container_internal;
namespace boost::beast {
template<class T>
bool operator==(const span<T>& lhs, const span<T>& rhs) {
return std::equal(
lhs.begin(), lhs.end(),
rhs.begin(), rhs.end());
}
}
// on-disk onode
// it only keeps the bits necessary to rebuild an in-memory onode
struct [[gnu::packed]] onode_t {
onode_t& operator=(const onode_t& onode) {
len = onode.len;
std::memcpy(data, onode.data, len);
return *this;
}
size_t size() const {
return sizeof(*this) + len;
}
OnodeRef decode() const {
return new crimson::os::seastore::Onode(std::string_view{data, len});
}
uint8_t struct_v = 1;
uint8_t struct_compat = 1;
// TODO:
// - use uint16_t for length, as the size of an onode should be less
// than a block (16K for now)
// - drop struct_len
uint32_t struct_len = 0;
uint32_t len;
char data[];
};
static inline std::ostream& operator<<(std::ostream& os, const onode_t& onode) {
return os << *onode.decode();
}
using crimson::os::seastore::laddr_t;
struct [[gnu::packed]] child_addr_t {
laddr_t data;
child_addr_t(laddr_t data)
: data{data}
{}
child_addr_t& operator=(laddr_t addr) {
data = addr;
return *this;
}
laddr_t get() const {
return data;
}
operator laddr_t() const {
return data;
}
size_t size() const {
return sizeof(laddr_t);
}
};
// poor man's operator<=>
enum class ordering_t {
less,
equivalent,
greater,
};
template<class L, class R>
ordering_t compare_element(const L& x, const R& y)
{
if constexpr (std::is_arithmetic_v<L>) {
static_assert(std::is_arithmetic_v<R>);
if (x < y) {
return ordering_t::less;
} else if (x > y) {
return ordering_t::greater;
} else {
return ordering_t::equivalent;
}
} else {
// string_view::compare(), string::compare(), ...
auto result = x.compare(y);
if (result < 0) {
return ordering_t::less;
} else if (result > 0) {
return ordering_t::greater;
} else {
return ordering_t::equivalent;
}
}
}
template<typename L, typename R>
constexpr ordering_t tuple_cmp(const L&, const R&, std::index_sequence<>)
{
return ordering_t::equivalent;
}
template<typename L, typename R,
size_t Head, size_t... Tail>
constexpr ordering_t tuple_cmp(const L& x, const R& y,
std::index_sequence<Head, Tail...>)
{
auto ordering = compare_element(std::get<Head>(x), std::get<Head>(y));
if (ordering != ordering_t::equivalent) {
return ordering;
} else {
return tuple_cmp(x, y, std::index_sequence<Tail...>());
}
}
template<typename... Ls, typename... Rs>
constexpr ordering_t cmp(const std::tuple<Ls...>& x,
const std::tuple<Rs...>& y)
{
static_assert(sizeof...(Ls) == sizeof...(Rs));
return tuple_cmp(x, y, std::index_sequence_for<Ls...>());
}
enum class likes_t {
yes,
no,
maybe,
};
struct [[gnu::packed]] variable_key_suffix {
uint64_t snap;
uint64_t gen;
uint8_t nspace_len;
uint8_t name_len;
char data[];
struct index_t {
enum {
nspace_data = 0,
name_data = 1,
};
};
using layout_type = asci::Layout<char, char>;
layout_type cell_layout() const {
return layout_type{nspace_len, name_len};
}
void set(const ghobject_t& oid) {
snap = oid.hobj.snap;
gen = oid.generation;
nspace_len = oid.hobj.nspace.size();
name_len = oid.hobj.oid.name.size();
auto layout = cell_layout();
std::memcpy(layout.Pointer<index_t::nspace_data>(data),
oid.hobj.nspace.data(), oid.hobj.nspace.size());
std::memcpy(layout.Pointer<index_t::name_data>(data),
oid.hobj.oid.name.data(), oid.hobj.oid.name.size());
}
void update_oid(ghobject_t& oid) const {
oid.hobj.snap = snap;
oid.generation = gen;
oid.hobj.nspace = nspace();
oid.hobj.oid.name = name();
}
variable_key_suffix& operator=(const variable_key_suffix& key) {
snap = key.snap;
gen = key.gen;
auto layout = cell_layout();
auto nspace = key.nspace();
std::copy_n(nspace.data(), nspace.size(),
layout.Pointer<index_t::nspace_data>(data));
auto name = key.name();
std::copy_n(name.data(), name.size(),
layout.Pointer<index_t::name_data>(data));
return *this;
}
const std::string_view nspace() const {
auto layout = cell_layout();
auto nspace = layout.Slice<index_t::nspace_data>(data);
return {nspace.data(), nspace.size()};
}
const std::string_view name() const {
auto layout = cell_layout();
auto name = layout.Slice<index_t::name_data>(data);
return {name.data(), name.size()};
}
size_t size() const {
return sizeof(*this) + nspace_len + name_len;
}
static size_t size_from(const ghobject_t& oid) {
return (sizeof(variable_key_suffix) +
oid.hobj.nspace.size() +
oid.hobj.oid.name.size());
}
ordering_t compare(const ghobject_t& oid) const {
return cmp(std::tie(nspace(), name(), snap, gen),
std::tie(oid.hobj.nspace, oid.hobj.oid.name, oid.hobj.snap.val,
oid.generation));
}
bool likes(const variable_key_suffix& key) const {
return nspace() == key.nspace() && name() == key.name();
}
};
static inline std::ostream& operator<<(std::ostream& os, const variable_key_suffix& k) {
if (k.snap != CEPH_NOSNAP) {
os << "s" << k.snap << ",";
}
if (k.gen != ghobject_t::NO_GEN) {
os << "g" << k.gen << ",";
}
return os << k.nspace() << "/" << k.name();
}
// should use [[no_unique_address]] in C++20
struct empty_key_suffix {
static constexpr ordering_t compare(const ghobject_t&) {
return ordering_t::equivalent;
}
static void set(const ghobject_t&) {}
static constexpr size_t size() {
return 0;
}
static size_t size_from(const ghobject_t&) {
return 0;
}
static void update_oid(ghobject_t&) {}
};
static inline std::ostream& operator<<(std::ostream& os, const empty_key_suffix&)
{
return os;
}
enum class ntype_t : uint8_t {
leaf = 0u,
inner,
};
constexpr ntype_t flip_ntype(ntype_t ntype) noexcept
{
if (ntype == ntype_t::leaf) {
return ntype_t::inner;
} else {
return ntype_t::leaf;
}
}
template<int N, ntype_t NodeType>
struct FixedKeyPrefix {};
template<ntype_t NodeType>
struct FixedKeyPrefix<0, NodeType>
{
static constexpr bool item_in_key = false;
int8_t shard = -1;
int64_t pool = -1;
uint32_t hash = 0;
uint16_t offset = 0;
FixedKeyPrefix() = default;
FixedKeyPrefix(const ghobject_t& oid, uint16_t offset)
: shard{oid.shard_id},
pool{oid.hobj.pool},
hash{oid.hobj.get_hash()},
offset{offset}
{}
void set(const ghobject_t& oid, uint16_t new_offset) {
shard = oid.shard_id;
pool = oid.hobj.pool;
hash = oid.hobj.get_hash();
offset = new_offset;
}
void set(const FixedKeyPrefix& k, uint16_t new_offset) {
shard = k.shard;
pool = k.pool;
hash = k.hash;
offset = new_offset;
}
void update(const ghobject_t& oid) {
shard = oid.shard_id;
pool = oid.hobj.pool;
hash = oid.hobj.get_hash();
}
void update_oid(ghobject_t& oid) const {
oid.set_shard(shard_id_t{shard});
oid.hobj.pool = pool;
oid.hobj.set_hash(hash);
}
ordering_t compare(const ghobject_t& oid) const {
// so std::tie() can bind them by reference
int8_t rhs_shard = oid.shard_id;
uint32_t rhs_hash = oid.hobj.get_hash();
return cmp(std::tie(shard, pool, hash),
std::tie(rhs_shard, oid.hobj.pool, rhs_hash));
}
// @return true if i likes @c k, we will can be pushed down to next level
// in the same node
likes_t likes(const FixedKeyPrefix& k) const {
if (shard == k.shard && pool == k.pool) {
return likes_t::yes;
} else {
return likes_t::no;
}
}
};
template<ntype_t NodeType>
std::ostream& operator<<(std::ostream& os, const FixedKeyPrefix<0, NodeType>& k) {
if (k.shard != shard_id_t::NO_SHARD) {
os << "s" << k.shard;
}
return os << "p=" << k.pool << ","
<< "h=" << std::hex << k.hash << std::dec << ","
<< ">" << k.offset;
}
// all elements in this node share the same <shard, pool>
template<ntype_t NodeType>
struct FixedKeyPrefix<1, NodeType> {
static constexpr bool item_in_key = false;
uint32_t hash = 0;
uint16_t offset = 0;
FixedKeyPrefix() = default;
FixedKeyPrefix(uint32_t hash, uint16_t offset)
: hash{hash},
offset{offset}
{}
FixedKeyPrefix(const ghobject_t& oid, uint16_t offset)
: FixedKeyPrefix(oid.hobj.get_hash(), offset)
{}
void set(const ghobject_t& oid, uint16_t new_offset) {
hash = oid.hobj.get_hash();
offset = new_offset;
}
template<int N>
void set(const FixedKeyPrefix<N, NodeType>& k, uint16_t new_offset) {
static_assert(N < 2, "only N0, N1 have hash");
hash = k.hash;
offset = new_offset;
}
void update_oid(ghobject_t& oid) const {
oid.hobj.set_hash(hash);
}
void update(const ghobject_t& oid) {
hash = oid.hobj.get_hash();
}
ordering_t compare(const ghobject_t& oid) const {
return compare_element(hash, oid.hobj.get_hash());
}
likes_t likes(const FixedKeyPrefix& k) const {
return hash == k.hash ? likes_t::yes : likes_t::no;
}
};
template<ntype_t NodeType>
std::ostream& operator<<(std::ostream& os, const FixedKeyPrefix<1, NodeType>& k) {
return os << "0x" << std::hex << k.hash << std::dec << ","
<< ">" << k.offset;
}
// all elements in this node must share the same <shard, pool, hash>
template<ntype_t NodeType>
struct FixedKeyPrefix<2, NodeType> {
static constexpr bool item_in_key = false;
uint16_t offset = 0;
FixedKeyPrefix() = default;
static constexpr ordering_t compare(const ghobject_t& oid) {
// need to compare the cell
return ordering_t::equivalent;
}
// always defer to my cell for likeness
constexpr likes_t likes(const FixedKeyPrefix&) const {
return likes_t::maybe;
}
void set(const ghobject_t&, uint16_t new_offset) {
offset = new_offset;
}
template<int N>
void set(const FixedKeyPrefix<N, NodeType>&, uint16_t new_offset) {
offset = new_offset;
}
void update(const ghobject_t&) {}
void update_oid(ghobject_t&) const {}
};
template<ntype_t NodeType>
std::ostream& operator<<(std::ostream& os, const FixedKeyPrefix<2, NodeType>& k) {
return os << ">" << k.offset;
}
struct fixed_key_3 {
uint64_t snap = 0;
uint64_t gen = 0;
fixed_key_3() = default;
fixed_key_3(const ghobject_t& oid)
: snap{oid.hobj.snap}, gen{oid.generation}
{}
ordering_t compare(const ghobject_t& oid) const {
return cmp(std::tie(snap, gen),
std::tie(oid.hobj.snap.val, oid.generation));
}
// no object likes each other at this level
constexpr likes_t likes(const fixed_key_3&) const {
return likes_t::no;
}
void update_with_oid(const ghobject_t& oid) {
snap = oid.hobj.snap;
gen = oid.generation;
}
void update_oid(ghobject_t& oid) const {
oid.hobj.snap = snap;
oid.generation = gen;
}
};
static inline std::ostream& operator<<(std::ostream& os, const fixed_key_3& k) {
if (k.snap != CEPH_NOSNAP) {
os << "s" << k.snap << ",";
}
if (k.gen != ghobject_t::NO_GEN) {
os << "g" << k.gen << ",";
}
return os;
}
// all elements in this node must share the same <shard, pool, hash, namespace, oid>
// but the unlike other FixedKeyPrefix<>, a node with FixedKeyPrefix<3> does not have
// variable_sized_key, so if it is an inner node, we can just embed the child
// addr right in the key.
template<>
struct FixedKeyPrefix<3, ntype_t::inner> : public fixed_key_3 {
// the item is embedded in the key
static constexpr bool item_in_key = true;
laddr_t child_addr = 0;
FixedKeyPrefix() = default;
void set(const ghobject_t& oid, laddr_t new_child_addr) {
update_with_oid(oid);
child_addr = new_child_addr;
}
// unlikely get called, though..
void update(const ghobject_t& oid) {}
template<int N>
std::enable_if_t<N < 3> set(const FixedKeyPrefix<N, ntype_t::inner>&,
laddr_t new_child_addr) {
child_addr = new_child_addr;
}
void set(const FixedKeyPrefix& k, laddr_t new_child_addr) {
snap = k.snap;
gen = k.gen;
child_addr = new_child_addr;
}
void set(const variable_key_suffix& k, laddr_t new_child_addr) {
snap = k.snap;
gen = k.gen;
child_addr = new_child_addr;
}
};
template<>
struct FixedKeyPrefix<3, ntype_t::leaf> : public fixed_key_3 {
static constexpr bool item_in_key = false;
uint16_t offset = 0;
FixedKeyPrefix() = default;
void set(const ghobject_t& oid, uint16_t new_offset) {
update_with_oid(oid);
offset = new_offset;
}
void set(const FixedKeyPrefix& k, uint16_t new_offset) {
snap = k.snap;
gen = k.gen;
offset = new_offset;
}
template<int N>
std::enable_if_t<N < 3> set(const FixedKeyPrefix<N, ntype_t::leaf>&,
uint16_t new_offset) {
offset = new_offset;
}
};
struct tag_t {
template<int N, ntype_t node_type>
static constexpr tag_t create() {
static_assert(std::clamp(N, 0, 3) == N);
return tag_t{N, static_cast<uint8_t>(node_type)};
}
bool is_leaf() const {
return type() == ntype_t::leaf;
}
int layout() const {
return layout_type;
}
ntype_t type() const {
return ntype_t{node_type};
}
int layout_type : 4;
uint8_t node_type : 4;
};
static inline std::ostream& operator<<(std::ostream& os, const tag_t& tag) {
return os << "n=" << tag.layout() << ", leaf=" << tag.is_leaf();
}
// for calculating size of variable-sized item/key
template<class T>
size_t size_of(const T& t) {
using decayed_t = std::decay_t<T>;
if constexpr (std::is_scalar_v<decayed_t>) {
return sizeof(decayed_t);
} else {
return t.size();
}
}
enum class size_state_t {
okay,
underflow,
overflow,
};
// layout of a node of B+ tree
//
// it is different from a typical B+ tree in following ways
// - the size of keys is not necessarily fixed, neither is the size of value.
// - the max number of elements in a node is determined by the total size of
// the keys and values in the node
// - in internal nodes, each key maps to the logical address of the child
// node whose minimum key is greater or equal to that key.
template<size_t BlockSize,
int N,
ntype_t NodeType>
struct node_t {
static_assert(std::clamp(N, 0, 3) == N);
constexpr static ntype_t node_type = NodeType;
constexpr static int node_n = N;
using key_prefix_t = FixedKeyPrefix<N, NodeType>;
using item_t = std::conditional_t<NodeType == ntype_t::leaf,
onode_t,
child_addr_t>;
using const_item_t = std::conditional_t<NodeType == ntype_t::leaf,
const onode_t&,
child_addr_t>;
static constexpr bool item_in_key = key_prefix_t::item_in_key;
using key_suffix_t = std::conditional_t<N < 3,
variable_key_suffix,
empty_key_suffix>;
std::pair<const key_prefix_t&, const key_suffix_t&>
key_at(unsigned slot) const;
// update an existing oid with the specified item
ghobject_t get_oid_at(unsigned slot, const ghobject_t& oid) const;
const_item_t item_at(const key_prefix_t& key) const;
void dump(std::ostream& os) const;
// for debugging only.
static constexpr bool is_leaf() {
return node_type == ntype_t::leaf;
}
bool _is_leaf() const {
return tag.is_leaf();
}
char* from_end(uint16_t offset);
const char* from_end(uint16_t offset) const;
uint16_t used_space() const;
uint16_t free_space() const {
return capacity() - used_space();
}
static uint16_t capacity();
// TODO: if it's allowed to update 2 siblings at the same time, we can have
// B* tree
static constexpr uint16_t min_size();
// calculate the allowable bounds on bytes to remove from an overflow node
// with specified size
// @param size the overflowed size
// @return <minimum bytes to grab, maximum bytes to grab>
static constexpr std::pair<int16_t, int16_t> bytes_to_remove(uint16_t size);
// calculate the allowable bounds on bytes to add to an underflow node
// with specified size
// @param size the underflowed size
// @return <minimum bytes to push, maximum bytes to push>
static constexpr std::pair<int16_t, int16_t> bytes_to_add(uint16_t size);
size_state_t size_state(uint16_t size) const;
bool is_underflow(uint16_t size) const;
int16_t size_with_key(unsigned slot, const ghobject_t& oid) const;
ordering_t compare_with_slot(unsigned slot, const ghobject_t& oid) const;
/// return the slot number of the first slot that is greater or equal to
/// key
std::pair<unsigned, bool> lower_bound(const ghobject_t& oid) const;
static uint16_t size_of_item(const ghobject_t& oid, const item_t& item);
bool is_overflow(const ghobject_t& oid, const item_t& item) const;
bool is_overflow(const ghobject_t& oid, const OnodeRef& item) const;
// inserts an item into the given slot, pushing all subsequent keys forward
// @note if the item is not embedded in key, shift the right half as well
void insert_at(unsigned slot, const ghobject_t& oid, const item_t& item);
// used by InnerNode for updating the keys indexing its children when their lower boundaries
// is updated
void update_key_at(unsigned slot, const ghobject_t& oid);
// try to figure out the number of elements and total size when trying to
// rebalance by moving the elements from the front of this node when its
// left sibling node is underflow
//
// @param min_grab lower bound of the number of bytes to move
// @param max_grab upper bound of the number of bytes to move
// @return the number of element to grab
// @note return {0, 0} if current node would be underflow if
// @c min_grab bytes of elements are taken from it
std::pair<unsigned, uint16_t> calc_grab_front(uint16_t min_grab, uint16_t max_grab) const;
// try to figure out the number of elements and their total size when trying to
// rebalance by moving the elements from the end of this node when its right
// sibling node is underflow
//
// @param min_grab lower bound of the number of bytes to move
// @param max_grab upper bound of the number of bytes to move
// @return the number of element to grab
// @note return {0, 0} if current node would be underflow if
// @c min_grab bytes of elements are taken from it
std::pair<unsigned, uint16_t> calc_grab_back(uint16_t min_grab, uint16_t max_grab) const;
template<int LeftN, class Mover> void grab_from_left(
node_t<BlockSize, LeftN, NodeType>& left,
unsigned n, uint16_t bytes,
Mover& mover);
template<int RightN, class Mover>
delta_t acquire_right(node_t<BlockSize, RightN, NodeType>& right,
unsigned whoami, Mover& mover);
// transfer n elements at the front of given node to me
template<int RightN, class Mover>
void grab_from_right(node_t<BlockSize, RightN, NodeType>& right,
unsigned n, uint16_t bytes,
Mover& mover);
template<int LeftN, class Mover>
void push_to_left(node_t<BlockSize, LeftN, NodeType>& left,
unsigned n, uint16_t bytes,
Mover& mover);
template<int RightN, class Mover>
void push_to_right(node_t<BlockSize, RightN, NodeType>& right,
unsigned n, uint16_t bytes,
Mover& mover);
// [to, from) are removed, so we need to shift left
// actually there are only two use cases:
// - to = 0: for giving elements in bulk
// - to = from - 1: for removing a single element
// old: |////|.....| |.....|/|........|
// new: |.....| |.....||........|
void shift_left(unsigned from, unsigned to);
void insert_front(const ceph::bufferptr& keys_buf, const ceph::bufferptr& cells_buf);
void insert_back(const ceph::bufferptr& keys_buf, const ceph::bufferptr& cells_buf);
// one or more elements are inserted, so we need to shift the elements right
// actually there are only two use cases:
// - bytes != 0: for inserting bytes before from
// - bytes = 0: for inserting a single element before from
// old: ||.....|
// new: |/////|.....|
void shift_right(unsigned n, unsigned bytes);
// shift all keys after slot is removed.
// @note if the item is not embdedded in key, all items sitting at the left
// side of it will be shifted right
void remove_from(unsigned slot);
void trim_right(unsigned n);
void play_delta(const delta_t& delta);
// /-------------------------------|
// | V
// |header|k0|k1|k2|... | / / |k2'v2|k1'v1|k0'.v0| v_m |
// |<-- count -->|
tag_t tag = tag_t::create<N, NodeType>();
// the count of values in the node
uint16_t count = 0;
key_prefix_t keys[];
};
template<class parent_t,
class from_t,
class to_t,
typename=void>
class EntryMover {
public:
// a "trap" mover
EntryMover(const parent_t&, from_t&, to_t& dst, unsigned) {
assert(0);
}
void move_from(unsigned, unsigned, unsigned) {
assert(0);
}
delta_t get_delta() {
return delta_t::nop();
}
};
// lower the layout, for instance, from L0 to L1, no reference oid is used
template<class parent_t,
class from_t,
class to_t>
class EntryMover<parent_t,
from_t,
to_t,
std::enable_if_t<from_t::node_n < to_t::node_n>>
{
public:
EntryMover(const parent_t&, from_t& src, to_t& dst, unsigned)
: src{src}, dst{dst}
{}
void move_from(unsigned src_first, unsigned dst_first, unsigned n)
{
ceph::bufferptr keys_buf{n * sizeof(to_t::key_prefix_t)};
ceph::bufferptr cells_buf;
auto dst_keys = reinterpret_cast<typename to_t::key_prefix_t*>(keys_buf.c_str());
if constexpr (to_t::item_in_key) {
for (unsigned i = 0; i < n; i++) {
const auto& [prefix, suffix] = src.key_at(src_first + i);
dst_keys[i].set(suffix, src.item_at(prefix));
}
} else {
// copy keys
uint16_t src_offset = src_first > 0 ? src.keys[src_first - 1].offset : 0;
uint16_t dst_offset = dst_first > 0 ? dst.keys[dst_first - 1].offset : 0;
for (unsigned i = 0; i < n; i++) {
auto& src_key = src.keys[src_first + i];
uint16_t offset = src_key.offset - src_offset + dst_offset;
dst_keys[i].set(src_key, offset);
}
// copy cells in bulk, yay!
auto src_end = src.keys[src_first + n - 1].offset;
uint16_t total_cell_size = src_end - src_offset;
cells_buf = ceph::bufferptr{total_cell_size};
cells_buf.copy_in(0, total_cell_size, src.from_end(src_end));
}
if (dst_first == dst.count) {
dst_delta = delta_t::insert_back(keys_buf, cells_buf);
} else {
dst_delta = delta_t::insert_front(keys_buf, cells_buf);
}
if (src_first > 0 && src_first + n == src.count) {
src_delta = delta_t::trim_right(src_first);
} else if (src_first == 0 && n < src.count) {
src_delta = delta_t::shift_left(n);
} else if (src_first == 0 && n == src.count) {
// the caller will retire the src extent
} else {
// grab in the middle?
assert(0);
}
}
delta_t from_delta() {
return std::move(src_delta);
}
delta_t to_delta() {
return std::move(dst_delta);
}
private:
const from_t& src;
const to_t& dst;
delta_t dst_delta;
delta_t src_delta;
};
// lift the layout, for instance, from L2 to L0, need a reference oid
template<class parent_t,
class from_t,
class to_t>
class EntryMover<parent_t, from_t, to_t,
std::enable_if_t<(from_t::node_n > to_t::node_n)>>
{
public:
EntryMover(const parent_t& parent, from_t& src, to_t& dst, unsigned from_slot)
: src{src}, dst{dst}, ref_oid{parent->get_oid_at(from_slot, {})}
{}
void move_from(unsigned src_first, unsigned dst_first, unsigned n)
{
ceph::bufferptr keys_buf{n * sizeof(to_t::key_prefix_t)};
ceph::bufferptr cells_buf;
auto dst_keys = reinterpret_cast<typename to_t::key_prefix_t*>(keys_buf.c_str());
uint16_t in_node_offset = dst_first > 0 ? dst.keys[dst_first - 1].offset : 0;
static_assert(!std::is_same_v<typename to_t::key_suffix_t, empty_key_suffix>);
// copy keys
uint16_t buf_offset = 0;
for (unsigned i = 0; i < n; i++) {
auto& src_key = src.keys[src_first + i];
if constexpr (std::is_same_v<typename from_t::key_suffix_t, empty_key_suffix>) {
// heterogeneous partial key, have to rebuild dst partial key from oid
src_key.update_oid(ref_oid);
const auto& src_item = src.item_at(src_key);
size_t key2_size = to_t::key_suffix_t::size_from(ref_oid);
buf_offset += key2_size + size_of(src_item);
dst_keys[i].set(ref_oid, in_node_offset + buf_offset);
auto p = from_end(cells_buf, buf_offset);
auto partial_key = reinterpret_cast<typename to_t::key_suffix_t*>(p);
partial_key->set(ref_oid);
p += key2_size;
auto dst_item = reinterpret_cast<typename to_t::item_t*>(p);
*dst_item = src_item;
} else {
// homogeneous partial key, just update the pointers
uint16_t src_offset = src_first > 0 ? src.keys[src_first - 1].offset : 0;
uint16_t dst_offset = dst_first > 0 ? dst.keys[dst_first - 1].offset : 0;
uint16_t offset = src_key.offset - src_offset + dst_offset;
dst_keys[i].set(ref_oid, in_node_offset + offset);
}
}
if constexpr (std::is_same_v<typename to_t::key_suffix_t,
typename from_t::key_suffix_t>) {
// copy cells in bulk, yay!
uint16_t src_offset = src_first > 0 ? src.keys[src_first - 1].offset : 0;
uint16_t src_end = src.keys[src_first + n - 1].offset;
uint16_t total_cell_size = src_end - src_offset;
cells_buf.copy_in(0, total_cell_size, src.from_end(src_end));
}
if (dst_first == dst.count) {
dst_delta = delta_t::insert_back(keys_buf, cells_buf);
} else {
dst_delta = delta_t::insert_front(keys_buf, cells_buf);
}
if (src_first + n == src.count && src_first > 0) {
src_delta = delta_t::trim_right(src_first);
} else {
// the caller will retire the src extent
assert(src_first == 0);
}
}
delta_t from_delta() {
return std::move(src_delta);
}
delta_t to_delta() {
return std::move(dst_delta);
}
private:
char* from_end(ceph::bufferptr& ptr, uint16_t offset) {
return ptr.end_c_str() - static_cast<int>(offset);
}
private:
const from_t& src;
const to_t& dst;
delta_t dst_delta;
delta_t src_delta;
ghobject_t ref_oid;
};
// identical layout, yay!
template<class parent_t,
class child_t>
class EntryMover<parent_t, child_t, child_t>
{
public:
EntryMover(const parent_t&, child_t& src, child_t& dst, unsigned)
: src{src}, dst{dst}
{}
void move_from(unsigned src_first, unsigned dst_first, unsigned n)
{
ceph::bufferptr keys_buf{static_cast<unsigned>(n * sizeof(typename child_t::key_prefix_t))};
ceph::bufferptr cells_buf;
auto dst_keys = reinterpret_cast<typename child_t::key_prefix_t*>(keys_buf.c_str());
// copy keys
std::copy(src.keys + src_first, src.keys + src_first + n,
dst_keys);
if constexpr (!child_t::item_in_key) {
uint16_t src_offset = src_first > 0 ? src.keys[src_first - 1].offset : 0;
uint16_t dst_offset = dst_first > 0 ? dst.keys[dst_first - 1].offset : 0;
const int offset_delta = dst_offset - src_offset;
// update the pointers
for (unsigned i = 0; i < n; i++) {
dst_keys[i].offset += offset_delta;
}
// copy cells in bulk, yay!
auto src_end = src.keys[src_first + n - 1].offset;
uint16_t total_cell_size = src_end - src_offset;
cells_buf = ceph::bufferptr{total_cell_size};
cells_buf.copy_in(0, total_cell_size, src.from_end(src_end));
}
if (dst_first == dst.count) {
dst_delta = delta_t::insert_back(std::move(keys_buf), std::move(cells_buf));
} else {
dst_delta = delta_t::insert_front(std::move(keys_buf), std::move(cells_buf));
}
if (src_first + n == src.count && src_first > 0) {
src_delta = delta_t::trim_right(n);
} else if (src_first == 0 && n < src.count) {
src_delta = delta_t::shift_left(n);
} else if (src_first == 0 && n == src.count) {
// the caller will retire the src extent
} else {
// grab in the middle?
assert(0);
}
}
delta_t from_delta() {
return std::move(src_delta);
}
delta_t to_delta() {
return std::move(dst_delta);
}
private:
char* from_end(ceph::bufferptr& ptr, uint16_t offset) {
return ptr.end_c_str() - static_cast<int>(offset);
}
private:
const child_t& src;
const child_t& dst;
delta_t src_delta;
delta_t dst_delta;
};
template<class parent_t, class from_t, class to_t>
EntryMover<parent_t, from_t, to_t>
make_mover(const parent_t& parent, from_t& src, to_t& dst, unsigned from_slot) {
return EntryMover<parent_t, from_t, to_t>(parent, src, dst, from_slot);
}
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