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59 lines
2.5 KiB
C++
59 lines
2.5 KiB
C++
/*****************************************************************************
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Copyright (c) 2020, Oracle and/or its affiliates. All Rights Reserved.
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Copyright (c) 2020, MariaDB Corporation.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License, version 2.0, as published by the
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Free Software Foundation.
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This program is also distributed with certain software (including but not
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limited to OpenSSL) that is licensed under separate terms, as designated in a
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particular file or component or in included license documentation. The authors
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of MySQL hereby grant you an additional permission to link the program and
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your derivative works with the separately licensed software that they have
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included with MySQL.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
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for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*****************************************************************************/
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#include "buf0block_hint.h"
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namespace buf {
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void Block_hint::buffer_fix_block_if_still_valid()
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{
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/* To check if m_block belongs to the current buf_pool, we must
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prevent freeing memory while we check, and until we buffer-fix the
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block. For this purpose it is enough to latch any of the many
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latches taken by buf_pool_t::resize().
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Similar to buf_page_optimistic_get(), we must validate
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m_block->page.id() after acquiring the hash_lock, because the object
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may have been freed and not actually attached to buf_pool.page_hash
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at the moment. (The block could have been reused to store a
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different page, and that slice of buf_pool.page_hash could be protected
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by another hash_lock that we are not holding.)
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Finally, assuming that we have correct hash bucket latched, we must
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validate m_block->state() to ensure that the block is not being freed. */
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if (m_block)
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{
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const ulint fold= m_page_id.fold();
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page_hash_latch *hash_lock= buf_pool.page_hash.lock<false>(fold);
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if (buf_pool.is_uncompressed(m_block) && m_page_id == m_block->page.id() &&
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m_block->page.state() == BUF_BLOCK_FILE_PAGE)
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buf_block_buf_fix_inc(m_block, __FILE__, __LINE__);
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else
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clear();
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hash_lock->read_unlock();
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}
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}
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} // namespace buf
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