mirror of
https://github.com/SerenityOS/serenity
synced 2026-05-09 00:22:43 +02:00
180f3f29ab
This is a large commit, since this is essentially a complete rewrite of the key low-level functions that handle reading/writing blocks. This is, however, a necessary prerequisite of being able to write holes. The previous version of `flush_block_list()` (along with its numerous helper functions) was entirely reliant on all blocks being sequential. In contrast to the previous implementation, the new version of `flush_block_list()` simply writes out the difference between the old block list and the new block list by calculating the correct indirect block(s) to update based on the relevant block's logical index. `compute_block_list()` has also been rewritten, since the estimated amount of meta blocks was incorrectly calculated for files with holes as a result of the estimated amount of blocks being a function of the file size. Since it isn't possible to accurately compute the shape of the block list without traversing it, we no longer try to perform such a computation, and instead simply search through all of the allocated indirect blocks. `compute_block_list_with_meta_blocks()` has also been removed in favor of the new `compute_meta_blocks()`, since meta blocks are fundamentally distinct from data blocks due to there being no mapping between any logical block index and the physical block index.
106 lines
4.5 KiB
C++
106 lines
4.5 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/HashMap.h>
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#include <Kernel/FileSystem/Ext2FS/Definitions.h>
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#include <Kernel/FileSystem/Ext2FS/DirectoryEntry.h>
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#include <Kernel/FileSystem/Ext2FS/FileSystem.h>
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#include <Kernel/FileSystem/Inode.h>
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#include <Kernel/UnixTypes.h>
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namespace Kernel {
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class Ext2FSInode final : public Inode {
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friend class Ext2FS;
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public:
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virtual ~Ext2FSInode() override;
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u64 size() const;
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bool is_symlink() const { return Kernel::is_symlink(m_raw_inode.i_mode); }
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bool is_directory() const { return Kernel::is_directory(m_raw_inode.i_mode); }
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private:
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// ^Inode
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virtual ErrorOr<size_t> read_bytes_locked(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
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virtual InodeMetadata metadata() const override;
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virtual ErrorOr<void> traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const override;
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virtual ErrorOr<NonnullRefPtr<Inode>> lookup(StringView name) override;
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virtual ErrorOr<void> flush_metadata() override;
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virtual ErrorOr<size_t> write_bytes_locked(off_t, size_t, UserOrKernelBuffer const& data, OpenFileDescription*) override;
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virtual ErrorOr<NonnullRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
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virtual ErrorOr<void> add_child(Inode& child, StringView name, mode_t) override;
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virtual ErrorOr<void> remove_child(StringView name) override;
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virtual ErrorOr<void> replace_child(StringView name, Inode& child) override;
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virtual ErrorOr<void> update_timestamps(Optional<UnixDateTime> atime, Optional<UnixDateTime> ctime, Optional<UnixDateTime> mtime) override;
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virtual ErrorOr<void> increment_link_count() override;
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virtual ErrorOr<void> decrement_link_count() override;
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virtual ErrorOr<void> chmod(mode_t) override;
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virtual ErrorOr<void> chown(UserID, GroupID) override;
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virtual ErrorOr<void> truncate_locked(u64) override;
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virtual ErrorOr<int> get_block_address(int) override;
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BlockBasedFileSystem::BlockIndex get_block(BlockBasedFileSystem::BlockIndex) const;
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ErrorOr<Vector<BlockBasedFileSystem::BlockIndex>> get_blocks(BlockBasedFileSystem::BlockIndex first_block_index, u64 count) const;
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ErrorOr<u32> allocate_and_zero_block();
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ErrorOr<void> write_directory(Vector<Ext2FSDirectoryEntry>&);
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ErrorOr<void> populate_lookup_cache();
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ErrorOr<void> resize(u64);
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ErrorOr<void> write_singly_indirect_block_pointer(BlockBasedFileSystem::BlockIndex logical_block_index, BlockBasedFileSystem::BlockIndex on_disk_index);
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ErrorOr<void> write_doubly_indirect_block_pointer(BlockBasedFileSystem::BlockIndex logical_block_index, BlockBasedFileSystem::BlockIndex on_disk_index);
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ErrorOr<void> write_triply_indirect_block_pointer(BlockBasedFileSystem::BlockIndex logical_block_index, BlockBasedFileSystem::BlockIndex on_disk_index);
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ErrorOr<void> write_block_pointer(BlockBasedFileSystem::BlockIndex logical_block_index, BlockBasedFileSystem::BlockIndex on_disk_index);
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ErrorOr<void> flush_block_list(Ext2FS::BlockList const& old_block_list);
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ErrorOr<void> compute_block_list_with_exclusive_locking();
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ErrorOr<Ext2FS::BlockList> compute_block_list() const;
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ErrorOr<Ext2FS::BlockList> compute_block_list_impl(Vector<Ext2FS::BlockIndex>* meta_blocks = nullptr) const;
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ErrorOr<Vector<Ext2FS::BlockIndex>> compute_meta_blocks() const;
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u64 singly_indirect_block_capacity() const
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{
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auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
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return EXT2_NDIR_BLOCKS + entries_per_block;
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}
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u64 doubly_indirect_block_capacity() const
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{
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auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
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return singly_indirect_block_capacity() + entries_per_block * entries_per_block;
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}
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u64 triply_indirect_block_capacity() const
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{
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auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
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return doubly_indirect_block_capacity() + entries_per_block * entries_per_block * entries_per_block;
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}
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Ext2FS& fs();
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Ext2FS const& fs() const;
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Ext2FSInode(Ext2FS&, InodeIndex);
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Ext2FS::BlockList m_block_list;
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HashMap<NonnullOwnPtr<KString>, InodeIndex> m_lookup_cache;
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ext2_inode m_raw_inode {};
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Mutex m_block_list_lock { "BlockList"sv };
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};
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inline Ext2FS& Ext2FSInode::fs()
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{
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return static_cast<Ext2FS&>(Inode::fs());
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}
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inline Ext2FS const& Ext2FSInode::fs() const
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{
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return static_cast<Ext2FS const&>(Inode::fs());
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}
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}
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