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	read_block() and write_block() now accept the count (how many bytes to read or write) and offset (where in the block to start; defaults to 0). Using these new APIs, we can avoid doing copies between intermediary buffers in a lot more cases. Hopefully this improves performance or something.
		
			
				
	
	
		
			77 lines
		
	
	
	
		
			3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			77 lines
		
	
	
	
		
			3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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|  * All rights reserved.
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|  *
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|  * Redistribution and use in source and binary forms, with or without
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|  * modification, are permitted provided that the following conditions are met:
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|  *
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|  * 1. Redistributions of source code must retain the above copyright notice, this
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|  *    list of conditions and the following disclaimer.
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|  *
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|  * 2. Redistributions in binary form must reproduce the above copyright notice,
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|  *    this list of conditions and the following disclaimer in the documentation
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|  *    and/or other materials provided with the distribution.
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|  *
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|  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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|  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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|  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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|  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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|  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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|  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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|  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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|  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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|  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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|  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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|  */
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| 
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| #pragma once
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| 
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| #include <Kernel/FileSystem/FileDescription.h>
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| #include <Kernel/FileSystem/FileSystem.h>
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| #include <Kernel/Forward.h>
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| 
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| namespace Kernel {
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| 
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| class FileBackedFS : public FS {
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| public:
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|     virtual ~FileBackedFS() override;
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| 
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|     File& file() { return m_file_description->file(); }
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|     FileDescription& file_description() { return *m_file_description; }
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|     const File& file() const { return m_file_description->file(); }
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|     const FileDescription& file_description() const { return *m_file_description; }
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| 
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|     virtual void flush_writes() override;
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| 
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|     void flush_writes_impl();
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| 
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|     size_t logical_block_size() const { return m_logical_block_size; };
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| 
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| protected:
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|     explicit FileBackedFS(FileDescription&);
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| 
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|     bool read_block(unsigned index, u8* buffer, size_t count, size_t offset = 0, bool allow_cache = true) const;
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|     bool read_blocks(unsigned index, unsigned count, u8* buffer, bool allow_cache = true) const;
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| 
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|     bool raw_read(unsigned index, u8* buffer);
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|     bool raw_write(unsigned index, const u8* buffer);
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| 
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|     bool raw_read_blocks(unsigned index, size_t count, u8* buffer);
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|     bool raw_write_blocks(unsigned index, size_t count, const u8* buffer);
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| 
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|     bool write_block(unsigned index, const u8* buffer, size_t count, size_t offset = 0, bool allow_cache = true);
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|     bool write_blocks(unsigned index, unsigned count, const u8*, bool allow_cache = true);
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| 
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|     size_t m_logical_block_size { 512 };
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| 
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| private:
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|     virtual bool is_file_backed() const override { return true; }
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| 
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|     DiskCache& cache() const;
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|     void flush_specific_block_if_needed(unsigned index);
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| 
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|     mutable NonnullRefPtr<FileDescription> m_file_description;
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|     mutable OwnPtr<DiskCache> m_cache;
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| };
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| 
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| }
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