98 lines
2.2 KiB
C++
98 lines
2.2 KiB
C++
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// Copyright (C) 2012 Red Hat, Inc. All rights reserved.
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//
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// This file is part of the thin-provisioning-tools source.
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//
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// thin-provisioning-tools is free software: you can redistribute it
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// and/or modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation, either version 3 of
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// the License, or (at your option) any later version.
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//
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// thin-provisioning-tools is distributed in the hope that it will be
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// useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with thin-provisioning-tools. If not, see
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// <http://www.gnu.org/licenses/>.
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#include "lock_tracker.h"
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#include <stdexcept>
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using namespace persistent_data;
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using namespace std;
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//----------------------------------------------------------------
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lock_tracker::lock_tracker(uint64_t low, uint64_t high)
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: low_(low),
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high_(high)
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{
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}
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void
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lock_tracker::read_lock(uint64_t key)
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{
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check_key(key);
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LockMap::const_iterator it = locks_.find(key);
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if (found(it)) {
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if (it->second < 0)
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throw runtime_error("already write locked");
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locks_.insert(make_pair(key, it->second + 1));
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} else
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locks_.insert(make_pair(key, 1));
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}
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void
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lock_tracker::write_lock(uint64_t key)
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{
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check_key(key);
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LockMap::const_iterator it = locks_.find(key);
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if (found(it))
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throw runtime_error("already locked");
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locks_.insert(make_pair(key, -1));
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}
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void
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lock_tracker::unlock(uint64_t key)
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{
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check_key(key);
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LockMap::const_iterator it = locks_.find(key);
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if (!found(it))
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throw runtime_error("not locked");
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if (it->second > 1)
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locks_.insert(make_pair(key, it->second - 1));
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else
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locks_.erase(key);
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}
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bool
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lock_tracker::found(LockMap::const_iterator it) const
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{
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return it != locks_.end();
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}
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bool
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lock_tracker::valid_key(uint64_t key) const
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{
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return (key >= low_ && key <= high_);
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}
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void
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lock_tracker::check_key(uint64_t key) const
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{
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if (!valid_key(key))
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throw runtime_error("invalid key");
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}
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//----------------------------------------------------------------
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