ladybird/Kernel/FileSystem/FileSystem.h
kleines Filmröllchen a6a439243f Kernel: Turn lock ranks into template parameters
This step would ideally not have been necessary (increases amount of
refactoring and templates necessary, which in turn increases build
times), but it gives us a couple of nice properties:
- SpinlockProtected inside Singleton (a very common combination) can now
  obtain any lock rank just via the template parameter. It was not
  previously possible to do this with SingletonInstanceCreator magic.
- SpinlockProtected's lock rank is now mandatory; this is the majority
  of cases and allows us to see where we're still missing proper ranks.
- The type already informs us what lock rank a lock has, which aids code
  readability and (possibly, if gdb cooperates) lock mismatch debugging.
- The rank of a lock can no longer be dynamic, which is not something we
  wanted in the first place (or made use of). Locks randomly changing
  their rank sounds like a disaster waiting to happen.
- In some places, we might be able to statically check that locks are
  taken in the right order (with the right lock rank checking
  implementation) as rank information is fully statically known.

This refactoring even more exposes the fact that Mutex has no lock rank
capabilites, which is not fixed here.
2023-01-02 18:15:27 -05:00

96 lines
2.7 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/AtomicRefCounted.h>
#include <AK/Error.h>
#include <AK/StringView.h>
#include <Kernel/FileSystem/InodeIdentifier.h>
#include <Kernel/Forward.h>
#include <Kernel/Library/LockRefPtr.h>
#include <Kernel/Locking/Mutex.h>
#include <Kernel/UnixTypes.h>
#include <Kernel/UserOrKernelBuffer.h>
namespace Kernel {
class FileSystem : public AtomicRefCounted<FileSystem> {
friend class Inode;
friend class VirtualFileSystem;
public:
virtual ~FileSystem();
FileSystemID fsid() const { return m_fsid; }
static void sync();
static void lock_all();
virtual ErrorOr<void> initialize() = 0;
virtual StringView class_name() const = 0;
virtual Inode& root_inode() = 0;
virtual bool supports_watchers() const { return false; }
bool is_readonly() const { return m_readonly; }
virtual unsigned total_block_count() const { return 0; }
virtual unsigned free_block_count() const { return 0; }
virtual unsigned total_inode_count() const { return 0; }
virtual unsigned free_inode_count() const { return 0; }
ErrorOr<void> prepare_to_unmount();
struct DirectoryEntryView {
DirectoryEntryView(StringView name, InodeIdentifier, u8 file_type);
StringView name;
InodeIdentifier inode;
u8 file_type { 0 };
};
virtual void flush_writes() { }
u64 block_size() const { return m_block_size; }
size_t fragment_size() const { return m_fragment_size; }
virtual bool is_file_backed() const { return false; }
// Converts file types that are used internally by the filesystem to DT_* types
virtual u8 internal_file_type_to_directory_entry_type(DirectoryEntryView const& entry) const { return entry.file_type; }
SpinlockProtected<size_t, LockRank::FileSystem>& mounted_count(Badge<VirtualFileSystem>) { return m_attach_count; }
protected:
FileSystem();
void set_block_size(u64 size) { m_block_size = size; }
void set_fragment_size(size_t size) { m_fragment_size = size; }
virtual ErrorOr<void> prepare_to_clear_last_mount() { return {}; }
mutable Mutex m_lock { "FS"sv };
private:
FileSystemID m_fsid;
u64 m_block_size { 0 };
size_t m_fragment_size { 0 };
bool m_readonly { false };
SpinlockProtected<size_t, LockRank::FileSystem> m_attach_count { 0 };
IntrusiveListNode<FileSystem> m_file_system_node;
};
}
namespace AK {
template<>
struct Traits<Kernel::InodeIdentifier> : public GenericTraits<Kernel::InodeIdentifier> {
static unsigned hash(Kernel::InodeIdentifier const& inode) { return pair_int_hash(inode.fsid().value(), inode.index().value()); }
};
}