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45b9675d28
The `compaction_strategy_state` class holds strategy specific state via
a `std::variant` containing different state types. When a compaction
strategy performs compaction, it retrieves a reference to its state from
the `compaction_strategy_state` object. If the table's compaction
strategy is ALTERed while a compaction is in progress, the
`compaction_strategy_state` object gets replaced, destroying the old
state. This leaves the ongoing compaction holding a dangling reference,
resulting in a use after free.
Fix this by using `seastar::shared_ptr` for the state variant
alternatives(`leveled_compaction_strategy_state_ptr` and
`time_window_compaction_strategy_state_ptr`). The compaction strategies
now hold a copy of the shared_ptr, ensuring the state remains valid for
the duration of the compaction even if the strategy is altered.
The `compaction_strategy_state` itself is still passed by reference and
only the variant alternatives use shared_ptrs. This allows ongoing
compactions to retain ownership of the state independently of the
wrapper's lifetime.
Fixes #25913
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
(cherry picked from commit 18c071c94b)
40 lines
928 B
C++
40 lines
928 B
C++
/*
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* Copyright (C) 2023-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
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*/
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#pragma once
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#include "time_window_compaction_strategy.hh"
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#include "leveled_compaction_strategy.hh"
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#include <utility>
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#include <variant>
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namespace compaction {
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class compaction_strategy_state {
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public:
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struct default_empty_state {};
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using states_variant = std::variant<default_empty_state, leveled_compaction_strategy_state_ptr, time_window_compaction_strategy_state_ptr>;
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private:
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states_variant _state;
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public:
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explicit compaction_strategy_state(states_variant state) : _state(std::move(state)) {
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}
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template <typename StateType>
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requires requires (StateType st) {
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{ states_variant{} = st };
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}
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StateType& get() noexcept {
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return std::get<StateType>(_state);
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}
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static compaction_strategy_state make(const compaction_strategy& cs);
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};
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}
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