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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/FileSystem.h>
30#include <Kernel/Forward.h>
31
32namespace Kernel {
33
34class DiskBackedFS : public FS {
35public:
36 virtual ~DiskBackedFS() override;
37
38 virtual bool is_disk_backed() const override { return true; }
39
40 BlockDevice& device() { return *m_device; }
41 const BlockDevice& device() const { return *m_device; }
42
43 virtual void flush_writes() override;
44
45 void flush_writes_impl();
46
47protected:
48 explicit DiskBackedFS(BlockDevice&);
49
50 bool read_block(unsigned index, u8* buffer, FileDescription* = nullptr) const;
51 bool read_blocks(unsigned index, unsigned count, u8* buffer, FileDescription* = nullptr) const;
52
53 bool write_block(unsigned index, const u8*, FileDescription* = nullptr);
54 bool write_blocks(unsigned index, unsigned count, const u8*, FileDescription* = nullptr);
55
56private:
57 DiskCache& cache() const;
58 void flush_specific_block_if_needed(unsigned index);
59
60 NonnullRefPtr<BlockDevice> m_device;
61 mutable OwnPtr<DiskCache> m_cache;
62};
63
64}