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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#pragma once
28
29#include <Kernel/FileSystem/FileDescription.h>
30#include <Kernel/FileSystem/FileSystem.h>
31#include <Kernel/Forward.h>
32
33namespace Kernel {
34
35class FileBackedFS : public FS {
36public:
37 virtual ~FileBackedFS() override;
38
39 virtual bool is_file_backed() const override { return true; }
40
41 File& file() { return m_file_description->file(); }
42 FileDescription& file_description() { return *m_file_description; }
43 const File& file() const { return m_file_description->file(); }
44 const FileDescription& file_description() const { return *m_file_description; }
45
46 virtual void flush_writes() override;
47
48 void flush_writes_impl();
49
50 size_t logical_block_size() const { return m_logical_block_size; };
51
52protected:
53 explicit FileBackedFS(FileDescription&);
54
55 bool read_block(unsigned index, u8* buffer, FileDescription* = nullptr) const;
56 bool read_blocks(unsigned index, unsigned count, u8* buffer, FileDescription* = nullptr) const;
57
58 bool raw_read(unsigned index, u8* buffer);
59 bool raw_write(unsigned index, const u8* buffer);
60
61 bool raw_read_blocks(unsigned index, size_t count, u8* buffer);
62 bool raw_write_blocks(unsigned index, size_t count, const u8* buffer);
63
64 bool write_block(unsigned index, const u8*, FileDescription* = nullptr);
65 bool write_blocks(unsigned index, unsigned count, const u8*, FileDescription* = nullptr);
66
67 size_t m_logical_block_size { 512 };
68
69private:
70 DiskCache& cache() const;
71 void flush_specific_block_if_needed(unsigned index);
72
73 NonnullRefPtr<FileDescription> m_file_description;
74 mutable OwnPtr<DiskCache> m_cache;
75};
76
77}