mirror of
https://github.com/SerenityOS/serenity
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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.
107 lines
3.4 KiB
C++
107 lines
3.4 KiB
C++
/*
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* Copyright (c) 2018-2021, 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/AtomicRefCounted.h>
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#include <AK/Error.h>
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#include <AK/StringView.h>
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#include <Kernel/FileSystem/InodeIdentifier.h>
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#include <Kernel/Forward.h>
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#include <Kernel/Library/LockRefPtr.h>
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#include <Kernel/Library/UserOrKernelBuffer.h>
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#include <Kernel/Locking/Mutex.h>
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#include <Kernel/UnixTypes.h>
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namespace Kernel {
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class FileSystem : public AtomicRefCounted<FileSystem> {
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friend class Inode;
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public:
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virtual ~FileSystem();
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FileSystemID fsid() const { return m_fsid; }
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static void sync();
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virtual ErrorOr<void> initialize() = 0;
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virtual StringView class_name() const = 0;
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virtual Inode& root_inode() = 0;
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virtual bool supports_watchers() const { return false; }
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virtual ErrorOr<void> rename(Inode& old_parent_inode, StringView old_basename, Inode& new_parent_inode, StringView new_basename) = 0;
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// FIXME: We should aim to provide more concise mechanism to ensure
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// that backing Inodes from the FileSystem are kept intact so we can
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// attach them to a loop device.
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virtual bool supports_backing_loop_devices() const { return false; }
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bool is_readonly() const { return m_readonly; }
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virtual unsigned total_block_count() const { return 0; }
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virtual unsigned free_block_count() const { return 0; }
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virtual unsigned total_inode_count() const { return 0; }
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virtual unsigned free_inode_count() const { return 0; }
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ErrorOr<void> prepare_to_unmount(Inode& mount_guest_inode);
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struct DirectoryEntryView {
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DirectoryEntryView(StringView name, InodeIdentifier, u8 file_type);
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StringView name;
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InodeIdentifier inode;
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u8 file_type { 0 };
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};
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virtual ErrorOr<void> flush_writes() { return {}; }
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u64 logical_block_size() const { return m_logical_block_size; }
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size_t fragment_size() const { return m_fragment_size; }
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virtual bool is_file_backed() const { return false; }
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// Converts file types that are used internally by the filesystem to DT_* types
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virtual u8 internal_file_type_to_directory_entry_type(DirectoryEntryView const& entry) const { return entry.file_type; }
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SpinlockProtected<size_t, LockRank::FileSystem>& mounted_count() { return m_attach_count; }
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protected:
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FileSystem();
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void set_logical_block_size(u64 size) { m_logical_block_size = size; }
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void set_fragment_size(size_t size) { m_fragment_size = size; }
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virtual ErrorOr<void> prepare_to_clear_last_mount([[maybe_unused]] Inode& mount_guest_inode) { return {}; }
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mutable Mutex m_lock { "FS"sv };
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private:
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FileSystemID m_fsid;
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u64 m_logical_block_size { 0 };
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size_t m_fragment_size { 0 };
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bool m_readonly { false };
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SpinlockProtected<size_t, LockRank::FileSystem> m_attach_count { 0 };
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IntrusiveListNode<FileSystem> m_file_system_node;
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public:
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using List = IntrusiveList<&FileSystem::m_file_system_node>;
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// NOTE: This method is implemented in Kernel/FileSystem/VirtualFileSystem.cpp
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static SpinlockProtected<FileSystem::List, LockRank::FileSystem>& all_file_systems_list();
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};
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}
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namespace AK {
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template<>
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struct Traits<Kernel::InodeIdentifier> : public DefaultTraits<Kernel::InodeIdentifier> {
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static unsigned hash(Kernel::InodeIdentifier const& inode) { return pair_int_hash(inode.fsid().value(), inode.index().value()); }
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};
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}
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