108 lines
2.8 KiB
C++
108 lines
2.8 KiB
C++
/*
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* Copyright (c) 2013, 2014, 2015, 2022 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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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 <assert.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 <unistd.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, const char* path, uint32_t block_size)
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{
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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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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->path = path;
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this->block_size = block_size;
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this->fd = fd;
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this->block_count = 0;
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#ifdef __sortix__
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// TODO: This isn't scaleable if there's multiple filesystems mounted.
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size_t memory;
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memstat(NULL, &memory);
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this->block_limit = (memory / 10) / block_size;
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#else
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this->block_limit = 32768;
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#endif
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}
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Device::~Device()
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{
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while ( mru_block )
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delete mru_block;
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close(fd);
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}
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Block* Device::AllocateBlock()
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{
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if ( block_limit <= block_count )
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{
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for ( Block* block = lru_block; block; block = block->prev_block )
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{
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if ( block->reference_count )
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continue;
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block->Destruct(); // Syncs.
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return block;
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}
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}
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uint8_t* data = new uint8_t[block_size];
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if ( !data ) // TODO: Use operator new nothrow!
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return NULL;
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Block* block = new Block();
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if ( !block ) // TODO: Use operator new nothrow!
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return delete[] data, (Block*) NULL;
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block->block_data = data;
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block_count++;
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return 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 = AllocateBlock();
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if ( !block )
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return NULL;
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block->Construct(this, block_id);
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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::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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