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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 <AK/Bitmap.h>
30#include <AK/HashMap.h>
31#include <Kernel/FileSystem/FileBackedFileSystem.h>
32#include <Kernel/FileSystem/Inode.h>
33#include <Kernel/FileSystem/ext2_fs.h>
34#include <Kernel/KBuffer.h>
35#include <Kernel/UnixTypes.h>
36
37struct ext2_group_desc;
38struct ext2_inode;
39struct ext2_super_block;
40
41namespace Kernel {
42
43class Ext2FS;
44
45class Ext2FSInode final : public Inode {
46 friend class Ext2FS;
47
48public:
49 virtual ~Ext2FSInode() override;
50
51 size_t size() const { return m_raw_inode.i_size; }
52 bool is_symlink() const { return Kernel::is_symlink(m_raw_inode.i_mode); }
53 bool is_directory() const { return Kernel::is_directory(m_raw_inode.i_mode); }
54
55 // ^Inode (RefCounted magic)
56 virtual void one_ref_left() override;
57
58private:
59 // ^Inode
60 virtual ssize_t read_bytes(off_t, ssize_t, u8* buffer, FileDescription*) const override;
61 virtual InodeMetadata metadata() const override;
62 virtual bool traverse_as_directory(Function<bool(const FS::DirectoryEntry&)>) const override;
63 virtual RefPtr<Inode> lookup(StringView name) override;
64 virtual void flush_metadata() override;
65 virtual ssize_t write_bytes(off_t, ssize_t, const u8* data, FileDescription*) override;
66 virtual KResult add_child(InodeIdentifier child_id, const StringView& name, mode_t) override;
67 virtual KResult remove_child(const StringView& name) override;
68 virtual int set_atime(time_t) override;
69 virtual int set_ctime(time_t) override;
70 virtual int set_mtime(time_t) override;
71 virtual KResult increment_link_count() override;
72 virtual KResult decrement_link_count() override;
73 virtual size_t directory_entry_count() const override;
74 virtual KResult chmod(mode_t) override;
75 virtual KResult chown(uid_t, gid_t) override;
76 virtual KResult truncate(u64) override;
77
78 bool write_directory(const Vector<FS::DirectoryEntry>&);
79 void populate_lookup_cache() const;
80 KResult resize(u64);
81
82 Ext2FS& fs();
83 const Ext2FS& fs() const;
84 Ext2FSInode(Ext2FS&, unsigned index);
85
86 mutable Vector<unsigned> m_block_list;
87 mutable HashMap<String, unsigned> m_lookup_cache;
88 ext2_inode m_raw_inode;
89};
90
91class Ext2FS final : public FileBackedFS {
92 friend class Ext2FSInode;
93
94public:
95 static NonnullRefPtr<Ext2FS> create(FileDescription&);
96
97 virtual ~Ext2FS() override;
98 virtual bool initialize() override;
99
100 virtual unsigned total_block_count() const override;
101 virtual unsigned free_block_count() const override;
102 virtual unsigned total_inode_count() const override;
103 virtual unsigned free_inode_count() const override;
104
105 virtual KResult prepare_to_unmount() const override;
106
107 virtual bool supports_watchers() const override { return true; }
108
109private:
110 typedef unsigned BlockIndex;
111 typedef unsigned GroupIndex;
112 typedef unsigned InodeIndex;
113 explicit Ext2FS(FileDescription&);
114
115 const ext2_super_block& super_block() const { return m_super_block; }
116 const ext2_group_desc& group_descriptor(GroupIndex) const;
117 ext2_group_desc* block_group_descriptors() { return (ext2_group_desc*)m_cached_group_descriptor_table.value().data(); }
118 const ext2_group_desc* block_group_descriptors() const { return (const ext2_group_desc*)m_cached_group_descriptor_table.value().data(); }
119 void flush_block_group_descriptor_table();
120 unsigned inodes_per_block() const;
121 unsigned inodes_per_group() const;
122 unsigned blocks_per_group() const;
123 unsigned inode_size() const;
124
125 bool write_ext2_inode(InodeIndex, const ext2_inode&);
126 bool read_block_containing_inode(InodeIndex inode, BlockIndex& block_index, unsigned& offset, u8* buffer) const;
127
128 bool flush_super_block();
129
130 virtual const char* class_name() const override;
131 virtual InodeIdentifier root_inode() const override;
132 virtual KResultOr<NonnullRefPtr<Inode>> create_inode(InodeIdentifier parent_id, const String& name, mode_t, off_t size, dev_t, uid_t, gid_t) override;
133 virtual KResult create_directory(InodeIdentifier parent_inode, const String& name, mode_t, uid_t, gid_t) override;
134 virtual RefPtr<Inode> get_inode(InodeIdentifier) const override;
135 virtual void flush_writes() override;
136
137 BlockIndex first_block_index() const;
138 InodeIndex find_a_free_inode(GroupIndex preferred_group, off_t expected_size);
139 Vector<BlockIndex> allocate_blocks(GroupIndex preferred_group_index, size_t count);
140 GroupIndex group_index_from_inode(InodeIndex) const;
141 GroupIndex group_index_from_block_index(BlockIndex) const;
142
143 Vector<BlockIndex> block_list_for_inode_impl(const ext2_inode&, bool include_block_list_blocks = false) const;
144 Vector<BlockIndex> block_list_for_inode(const ext2_inode&, bool include_block_list_blocks = false) const;
145 bool write_block_list_for_inode(InodeIndex, ext2_inode&, const Vector<BlockIndex>&);
146
147 bool get_inode_allocation_state(InodeIndex) const;
148 bool set_inode_allocation_state(InodeIndex, bool);
149 bool set_block_allocation_state(BlockIndex, bool);
150
151 void uncache_inode(InodeIndex);
152 void free_inode(Ext2FSInode&);
153
154 struct BlockListShape {
155 unsigned direct_blocks { 0 };
156 unsigned indirect_blocks { 0 };
157 unsigned doubly_indirect_blocks { 0 };
158 unsigned triply_indirect_blocks { 0 };
159 unsigned meta_blocks { 0 };
160 };
161
162 BlockListShape compute_block_list_shape(unsigned blocks);
163
164 unsigned m_block_group_count { 0 };
165
166 mutable ext2_super_block m_super_block;
167 mutable Optional<KBuffer> m_cached_group_descriptor_table;
168
169 mutable HashMap<InodeIndex, RefPtr<Ext2FSInode>> m_inode_cache;
170
171 bool m_super_block_dirty { false };
172 bool m_block_group_descriptors_dirty { false };
173
174 struct CachedBitmap {
175 CachedBitmap(BlockIndex bi, KBuffer&& buf)
176 : bitmap_block_index(bi)
177 , buffer(move(buf))
178 {
179 }
180 BlockIndex bitmap_block_index { 0 };
181 bool dirty { false };
182 KBuffer buffer;
183 Bitmap bitmap(u32 blocks_per_group) { return Bitmap::wrap(buffer.data(), blocks_per_group); }
184 };
185
186 CachedBitmap& get_bitmap_block(BlockIndex);
187
188 Vector<OwnPtr<CachedBitmap>> m_cached_bitmaps;
189};
190
191inline Ext2FS& Ext2FSInode::fs()
192{
193 return static_cast<Ext2FS&>(Inode::fs());
194}
195
196inline const Ext2FS& Ext2FSInode::fs() const
197{
198 return static_cast<const Ext2FS&>(Inode::fs());
199}
200
201}