mirror of
https://github.com/SerenityOS/serenity
synced 2026-05-11 17:37:00 +02:00
0e94887b2c
Previously, the VFS layer would try to handle renames more-or-less by itself, which really only worked for ext2, and even that was only due to the replace_child kludge existing specifically for this purpose. This never worked properly for FATFS, since the VFS layer effectively depended on filesystems having some kind of reference-counting for inodes, which is something that simply doesn't exist on any FAT variant we support. To resolve various issues with the existing scheme, this commit makes filesystem implementations themselves responsible for the actual rename operation, while keeping all the existing validation inside the VFS layer. The only intended behavior change here is that rename operations should actually properly work on FATFS.
111 lines
4.6 KiB
C++
111 lines
4.6 KiB
C++
/*
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* Copyright (c) 2022-2024, Undefine <undefine@undefine.pl>
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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/OwnPtr.h>
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#include <AK/RefPtr.h>
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#include <Kernel/FileSystem/FATFS/Definitions.h>
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#include <Kernel/FileSystem/FATFS/FileSystem.h>
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#include <Kernel/FileSystem/FATFS/SFNUtilities.h>
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#include <Kernel/FileSystem/Inode.h>
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#include <Kernel/Library/KBuffer.h>
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#include <Kernel/Library/KString.h>
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namespace Kernel {
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struct FATEntryLocation {
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BlockBasedFileSystem::BlockIndex block;
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u32 entry;
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};
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class FATInode final : public Inode {
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friend FATFS;
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public:
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virtual ~FATInode() override = default;
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static ErrorOr<NonnullRefPtr<FATInode>> create(FATFS&, FATEntry, FATEntryLocation inode_metadata_location, Vector<FATLongFileNameEntry> const& = {});
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FATFS& fs() { return static_cast<FATFS&>(Inode::fs()); }
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FATFS const& fs() const { return static_cast<FATFS const&>(Inode::fs()); }
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private:
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FATInode(FATFS&, FATEntry, FATEntryLocation inode_metadata_location, NonnullOwnPtr<KString> filename);
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static constexpr u8 end_entry_byte = 0x00;
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static constexpr u8 unused_entry_byte = 0xE5;
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static constexpr u8 lfn_entry_character_termination = 0x00;
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static constexpr u8 lfn_entry_unused_byte = 0xFF;
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static constexpr u8 normal_filename_length = 8;
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static constexpr u8 normal_extension_length = 3;
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static constexpr size_t lfn_entry_characters_part_1_length = 5;
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static constexpr size_t lfn_entry_characters_part_2_length = 6;
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static constexpr size_t lfn_entry_characters_part_3_length = 2;
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static constexpr size_t characters_per_lfn_entry = lfn_entry_characters_part_1_length + lfn_entry_characters_part_2_length + lfn_entry_characters_part_3_length;
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static constexpr u8 last_lfn_entry_mask = 0x40;
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static constexpr size_t max_filename_length = 255;
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static ErrorOr<NonnullOwnPtr<KString>> compute_filename(FATEntry&, Vector<FATLongFileNameEntry> const& = {});
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static StringView byte_terminated_string(StringView, u8);
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static u8 lfn_entry_checksum(FATEntry const& entry);
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static ErrorOr<void> create_unique_sfn_for(FATEntry& entry, NonnullRefPtr<SFNUtils::SFN> sfn, Vector<ByteBuffer> existing_sfns);
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static ErrorOr<void> encode_known_good_sfn_for(FATEntry& entry, StringView name);
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static ErrorOr<Vector<FATLongFileNameEntry>> create_lfn_entries(StringView name, u8 checksum);
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ErrorOr<Vector<u32>> compute_cluster_list(FATFS&, u32 first_cluster);
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ErrorOr<Vector<BlockBasedFileSystem::BlockIndex>> get_block_list();
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ErrorOr<NonnullOwnPtr<KBuffer>> read_block_list();
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ErrorOr<RefPtr<FATInode>> traverse(Function<ErrorOr<bool>(RefPtr<FATInode>)> callback);
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u32 first_cluster() const;
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// This overload of `first_cluster` does not rely on the base Inode
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// already being created to determine the FAT version. It is used
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// during FATInode creation (create()).
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static u32 first_cluster(FATVersion const version, u16 first_cluster_low, u16 first_cluster_high);
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ErrorOr<void> allocate_and_add_cluster_to_chain();
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ErrorOr<void> remove_last_cluster_from_chain();
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ErrorOr<Vector<FATEntryLocation>> allocate_entries(u32 count);
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ErrorOr<void> resize(u64 size);
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ErrorOr<Vector<ByteBuffer>> collect_sfns();
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enum class FreeClusters {
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Yes,
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No,
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};
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ErrorOr<void> remove_child_impl(StringView name, FreeClusters free_clusters);
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// ^Inode
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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<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<NonnullRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
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virtual ErrorOr<void> add_child(Inode&, StringView name, mode_t) override;
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virtual ErrorOr<void> remove_child(StringView name) 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<void> flush_metadata() override;
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virtual ErrorOr<void> update_timestamps(Optional<UnixDateTime> atime, Optional<UnixDateTime> ctime, Optional<UnixDateTime> mtime) override;
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Vector<u32> m_cluster_list;
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FATEntry m_entry;
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FATEntryLocation m_inode_metadata_location;
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NonnullOwnPtr<KString> m_filename;
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};
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}
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