116 lines
2.6 KiB
C++
116 lines
2.6 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013.
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This program is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the Free
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Software Foundation, either version 3 of the License, or (at your option)
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any later version.
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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
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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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, see <http://www.gnu.org/licenses/>.
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block.cpp
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Blocks in the filesystem.
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*******************************************************************************/
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#include <sys/types.h>
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#include <stddef.h>
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#include <stdint.h>
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#include "block.h"
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#include "device.h"
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#include "ioleast.h"
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Block::Block(Device* device, uint32_t block_id)
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{
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this->prev_block = NULL;
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this->next_block = NULL;
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this->prev_hashed = NULL;
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this->next_hashed = NULL;
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this->device = device;
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this->reference_count = 1;
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this->block_id = block_id;
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this->dirty = false;
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this->block_data = 0;
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}
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Block::~Block()
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{
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Sync();
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Unlink();
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delete[] block_data;
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}
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void Block::Refer()
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{
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reference_count++;
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}
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void Block::Unref()
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{
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if ( !--reference_count )
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#if 0
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delete this;
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#else
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{};
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#endif
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}
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void Block::Sync()
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{
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if ( !dirty )
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return;
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dirty = false;
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if ( !device->write )
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return;
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off_t file_offset = (off_t) device->block_size * (off_t) block_id;
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pwriteall(device->fd, block_data, device->block_size, file_offset);
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}
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void Block::Dirty()
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{
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dirty = true;
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Use();
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}
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void Block::Use()
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{
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Unlink();
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Prelink();
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}
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void Block::Unlink()
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{
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(prev_block ? prev_block->next_block : device->mru_block) = next_block;
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(next_block ? next_block->prev_block : device->lru_block) = prev_block;
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size_t bin = block_id % DEVICE_HASH_LENGTH;
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(prev_hashed ? prev_hashed->next_hashed : device->hash_blocks[bin]) = next_hashed;
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if ( next_hashed ) next_hashed->prev_hashed = prev_hashed;
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}
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void Block::Prelink()
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{
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prev_block = NULL;
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next_block = device->mru_block;
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if ( device->mru_block )
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device->mru_block->prev_block = this;
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device->mru_block = this;
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if ( !device->lru_block )
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device->lru_block = this;
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size_t bin = block_id % DEVICE_HASH_LENGTH;
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prev_hashed = NULL;
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next_hashed = device->hash_blocks[bin];
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device->hash_blocks[bin] = this;
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if ( next_hashed )
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next_hashed->prev_hashed = this;
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}
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