97 lines
2.5 KiB
C++
97 lines
2.5 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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device.cpp
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Block device.
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*******************************************************************************/
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#include <sys/stat.h>
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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 <string.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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Device::Device(int fd, uint32_t block_size, bool write)
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{
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this->write = write;
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this->fd = fd;
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this->block_size = block_size;
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struct stat st;
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fstat(fd, &st);
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this->device_size = st.st_size;
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this->mru_block = NULL;
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this->lru_block = NULL;
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for ( size_t i = 0; i < DEVICE_HASH_LENGTH; i++ )
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hash_blocks[i] = NULL;
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}
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Device::~Device()
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{
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Sync();
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while ( mru_block )
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delete mru_block;
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}
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Block* Device::GetBlock(uint32_t block_id)
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{
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if ( Block* block = GetCachedBlock(block_id) )
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return block;
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Block* block = new Block(this, block_id);
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block->block_data = new uint8_t[block_size];
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off_t file_offset = (off_t) block_size * (off_t) block_id;
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preadall(fd, block->block_data, block_size, file_offset);
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block->Prelink();
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return block;
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}
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Block* Device::GetBlockZeroed(uint32_t block_id)
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{
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if ( Block* block = GetCachedBlock(block_id) )
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{
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memset(block->block_data, 0, block_size);
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block->Dirty();
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return block;
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}
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Block* block = new Block(this, block_id);
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block->block_data = new uint8_t[block_size];
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memset(block->block_data, 0, block_size);
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block->Prelink();
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block->Dirty();
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return block;
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}
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Block* Device::GetCachedBlock(uint32_t block_id)
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{
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size_t bin = block_id % DEVICE_HASH_LENGTH;
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for ( Block* iter = hash_blocks[bin]; iter; iter = iter->next_hashed )
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if ( iter->block_id == block_id )
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return iter->Refer(), iter;
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return NULL;
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}
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void Device::Sync()
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{
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for ( Block* iter = mru_block; iter; iter = iter->next_block )
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iter->Sync();
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}
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