Kernel: Split the FATFileSystem.{cpp,h} files into smaller components

6 files changed, 330 insertions, 285 deletions

diff --git a/Kernel/FileSystem/FATFS/Definitions.h b/Kernel/FileSystem/FATFS/Definitions.h
new file mode 100644
index 0000000000..d0f47c57f5
--- /dev/null
+++ b/Kernel/FileSystem/FATFS/Definitions.h
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2022, Undefine <undefine@undefine.pl>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/EnumBits.h>
+#include <AK/Types.h>
+
+namespace Kernel {
+
+struct [[gnu::packed]] FAT32BootRecord {
+    u8 boot_jump[3];
+    char oem_identifier[8];
+    u16 bytes_per_sector;
+    u8 sectors_per_cluster;
+    u16 reserved_sector_count;
+    u8 fat_count;
+    u16 root_directory_entry_count;
+    u16 unused1;
+    u8 media_descriptor_type;
+    u16 unused2;
+    u16 sectors_per_track;
+    u16 head_count;
+    u32 hidden_sector_count;
+    u32 sector_count;
+    u32 sectors_per_fat;
+    u16 flags;
+    u16 fat_version;
+    u32 root_directory_cluster;
+    u16 fs_info_sector;
+    u16 backup_boot_sector;
+    u8 unused3[12];
+    u8 drive_number;
+    u8 unused4;
+    u8 signature;
+    u32 volume_id;
+    char volume_label_string[11];
+    char system_identifier_string[8];
+};
+static_assert(sizeof(FAT32BootRecord) == 90);
+
+enum class FATAttributes : u8 {
+    ReadOnly = 0x01,
+    Hidden = 0x02,
+    System = 0x04,
+    VolumeID = 0x08,
+    Directory = 0x10,
+    Archive = 0x20,
+    LongFileName = 0x0F
+};
+
+AK_ENUM_BITWISE_OPERATORS(FATAttributes);
+
+union FATPackedTime {
+    u16 value;
+    struct {
+        u16 second : 5;
+        u16 minute : 6;
+        u16 hour : 5;
+    };
+};
+static_assert(sizeof(FATPackedTime) == 2);
+
+union FATPackedDate {
+    u16 value;
+    struct {
+        u16 day : 5;
+        u16 month : 4;
+        u16 year : 7;
+    };
+};
+static_assert(sizeof(FATPackedDate) == 2);
+
+struct [[gnu::packed]] FATEntry {
+    char filename[8];
+    char extension[3];
+    FATAttributes attributes;
+    u8 unused1;
+    u8 creation_time_seconds;
+    FATPackedTime creation_time;
+    FATPackedDate creation_date;
+    FATPackedDate last_accessed_date;
+    u16 first_cluster_high;
+    FATPackedTime modification_time;
+    FATPackedDate modification_date;
+    u16 first_cluster_low;
+    u32 file_size;
+};
+static_assert(sizeof(FATEntry) == 32);
+
+struct [[gnu::packed]] FATLongFileNameEntry {
+    u8 entry_index;
+    u16 characters1[5];
+    FATAttributes attributes;
+    u8 entry_type;
+    u8 checksum;
+    u16 characters2[6];
+    u16 zero;
+    u16 characters3[2];
+};
+static_assert(sizeof(FATLongFileNameEntry) == 32);
+
+}
diff --git a/Kernel/FileSystem/FATFS/FileSystem.cpp b/Kernel/FileSystem/FATFS/FileSystem.cpp
new file mode 100644
index 0000000000..6e35f6aede
--- /dev/null
+++ b/Kernel/FileSystem/FATFS/FileSystem.cpp
@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2022, Undefine <undefine@undefine.pl>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/Debug.h>
+#include <Kernel/FileSystem/FATFS/FileSystem.h>
+#include <Kernel/FileSystem/FATFS/Inode.h>
+
+namespace Kernel {
+
+ErrorOr<NonnullLockRefPtr<FileSystem>> FATFS::try_create(OpenFileDescription& file_description)
+{
+    return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) FATFS(file_description)));
+}
+
+FATFS::FATFS(OpenFileDescription& file_description)
+    : BlockBasedFileSystem(file_description)
+{
+}
+
+bool FATFS::is_initialized_while_locked()
+{
+    VERIFY(m_lock.is_locked());
+    return !m_root_inode.is_null();
+}
+
+ErrorOr<void> FATFS::initialize_while_locked()
+{
+    VERIFY(m_lock.is_locked());
+    VERIFY(!is_initialized_while_locked());
+
+    m_boot_record = TRY(KBuffer::try_create_with_size("FATFS: Boot Record"sv, m_logical_block_size));
+    auto boot_record_buffer = UserOrKernelBuffer::for_kernel_buffer(m_boot_record->data());
+    TRY(raw_read(0, boot_record_buffer));
+
+    if constexpr (FAT_DEBUG) {
+        dbgln("FATFS: oem_identifier: {}", boot_record()->oem_identifier);
+        dbgln("FATFS: bytes_per_sector: {}", boot_record()->bytes_per_sector);
+        dbgln("FATFS: sectors_per_cluster: {}", boot_record()->sectors_per_cluster);
+        dbgln("FATFS: reserved_sector_count: {}", boot_record()->reserved_sector_count);
+        dbgln("FATFS: fat_count: {}", boot_record()->fat_count);
+        dbgln("FATFS: root_directory_entry_count: {}", boot_record()->root_directory_entry_count);
+        dbgln("FATFS: media_descriptor_type: {}", boot_record()->media_descriptor_type);
+        dbgln("FATFS: sectors_per_track: {}", boot_record()->sectors_per_track);
+        dbgln("FATFS: head_count: {}", boot_record()->head_count);
+        dbgln("FATFS: hidden_sector_count: {}", boot_record()->hidden_sector_count);
+        dbgln("FATFS: sector_count: {}", boot_record()->sector_count);
+        dbgln("FATFS: sectors_per_fat: {}", boot_record()->sectors_per_fat);
+        dbgln("FATFS: flags: {}", boot_record()->flags);
+        dbgln("FATFS: fat_version: {}", boot_record()->fat_version);
+        dbgln("FATFS: root_directory_cluster: {}", boot_record()->root_directory_cluster);
+        dbgln("FATFS: fs_info_sector: {}", boot_record()->fs_info_sector);
+        dbgln("FATFS: backup_boot_sector: {}", boot_record()->backup_boot_sector);
+        dbgln("FATFS: drive_number: {}", boot_record()->drive_number);
+        dbgln("FATFS: volume_id: {}", boot_record()->volume_id);
+    }
+
+    if (boot_record()->signature != signature_1 && boot_record()->signature != signature_2) {
+        dbgln("FATFS: Invalid signature");
+        return EINVAL;
+    }
+
+    m_logical_block_size = boot_record()->bytes_per_sector;
+    set_block_size(m_logical_block_size);
+
+    u32 root_directory_sectors = ((boot_record()->root_directory_entry_count * sizeof(FATEntry)) + (m_logical_block_size - 1)) / m_logical_block_size;
+    m_first_data_sector = boot_record()->reserved_sector_count + (boot_record()->fat_count * boot_record()->sectors_per_fat) + root_directory_sectors;
+
+    TRY(BlockBasedFileSystem::initialize_while_locked());
+
+    FATEntry root_entry {};
+
+    root_entry.first_cluster_low = boot_record()->root_directory_cluster & 0xFFFF;
+    root_entry.first_cluster_high = boot_record()->root_directory_cluster >> 16;
+
+    root_entry.attributes = FATAttributes::Directory;
+    m_root_inode = TRY(FATInode::create(*this, root_entry));
+
+    return {};
+}
+
+Inode& FATFS::root_inode()
+{
+    return *m_root_inode;
+}
+
+BlockBasedFileSystem::BlockIndex FATFS::first_block_of_cluster(u32 cluster) const
+{
+    return ((cluster - first_data_cluster) * boot_record()->sectors_per_cluster) + m_first_data_sector;
+}
+
+}
diff --git a/Kernel/FileSystem/FATFS/FileSystem.h b/Kernel/FileSystem/FATFS/FileSystem.h
new file mode 100644
index 0000000000..29c568153a
--- /dev/null
+++ b/Kernel/FileSystem/FATFS/FileSystem.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2022, Undefine <undefine@undefine.pl>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/OwnPtr.h>
+#include <AK/RefPtr.h>
+#include <AK/Types.h>
+#include <Kernel/FileSystem/BlockBasedFileSystem.h>
+#include <Kernel/FileSystem/FATFS/Definitions.h>
+#include <Kernel/FileSystem/Inode.h>
+#include <Kernel/Forward.h>
+#include <Kernel/KBuffer.h>
+
+namespace Kernel {
+
+class FATFS final : public BlockBasedFileSystem {
+    friend FATInode;
+
+public:
+    static ErrorOr<NonnullLockRefPtr<FileSystem>> try_create(OpenFileDescription&);
+
+    virtual ~FATFS() override = default;
+    virtual StringView class_name() const override { return "FATFS"sv; }
+    virtual Inode& root_inode() override;
+
+private:
+    virtual ErrorOr<void> initialize_while_locked() override;
+    virtual bool is_initialized_while_locked() override;
+    // FIXME: This is not a proper way to clear last mount of a FAT filesystem,
+    // but for now we simply have no other way to properly do it.
+    virtual ErrorOr<void> prepare_to_clear_last_mount() override { return {}; }
+
+    FATFS(OpenFileDescription&);
+
+    static constexpr u8 signature_1 = 0x28;
+    static constexpr u8 signature_2 = 0x29;
+
+    static constexpr u32 first_data_cluster = 2;
+
+    FAT32BootRecord const* boot_record() const { return reinterpret_cast<FAT32BootRecord const*>(m_boot_record->data()); };
+
+    BlockBasedFileSystem::BlockIndex first_block_of_cluster(u32 cluster) const;
+
+    OwnPtr<KBuffer> m_boot_record;
+    LockRefPtr<FATInode> m_root_inode;
+    u32 m_first_data_sector;
+};
+
+}
diff --git a/Kernel/FileSystem/FATFileSystem.cpp b/Kernel/FileSystem/FATFS/Inode.cpp
index 431c95ff8f..60422aa3d6 100644
--- a/Kernel/FileSystem/FATFileSystem.cpp
+++ b/Kernel/FileSystem/FATFS/Inode.cpp
@@ -6,93 +6,11 @@
 
 #include <AK/Time.h>
 #include <Kernel/Debug.h>
-#include <Kernel/Devices/BlockDevice.h>
-#include <Kernel/FileSystem/FATFileSystem.h>
-#include <Kernel/Memory/Region.h>
+#include <Kernel/FileSystem/FATFS/Inode.h>
+#include <Kernel/KBufferBuilder.h>
 
 namespace Kernel {
 
-ErrorOr<NonnullLockRefPtr<FileSystem>> FATFS::try_create(OpenFileDescription& file_description)
-{
-    return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) FATFS(file_description)));
-}
-
-FATFS::FATFS(OpenFileDescription& file_description)
-    : BlockBasedFileSystem(file_description)
-{
-}
-
-bool FATFS::is_initialized_while_locked()
-{
-    VERIFY(m_lock.is_locked());
-    return !m_root_inode.is_null();
-}
-
-ErrorOr<void> FATFS::initialize_while_locked()
-{
-    VERIFY(m_lock.is_locked());
-    VERIFY(!is_initialized_while_locked());
-
-    m_boot_record = TRY(KBuffer::try_create_with_size("FATFS: Boot Record"sv, m_logical_block_size));
-    auto boot_record_buffer = UserOrKernelBuffer::for_kernel_buffer(m_boot_record->data());
-    TRY(raw_read(0, boot_record_buffer));
-
-    if constexpr (FAT_DEBUG) {
-        dbgln("FATFS: oem_identifier: {}", boot_record()->oem_identifier);
-        dbgln("FATFS: bytes_per_sector: {}", boot_record()->bytes_per_sector);
-        dbgln("FATFS: sectors_per_cluster: {}", boot_record()->sectors_per_cluster);
-        dbgln("FATFS: reserved_sector_count: {}", boot_record()->reserved_sector_count);
-        dbgln("FATFS: fat_count: {}", boot_record()->fat_count);
-        dbgln("FATFS: root_directory_entry_count: {}", boot_record()->root_directory_entry_count);
-        dbgln("FATFS: media_descriptor_type: {}", boot_record()->media_descriptor_type);
-        dbgln("FATFS: sectors_per_track: {}", boot_record()->sectors_per_track);
-        dbgln("FATFS: head_count: {}", boot_record()->head_count);
-        dbgln("FATFS: hidden_sector_count: {}", boot_record()->hidden_sector_count);
-        dbgln("FATFS: sector_count: {}", boot_record()->sector_count);
-        dbgln("FATFS: sectors_per_fat: {}", boot_record()->sectors_per_fat);
-        dbgln("FATFS: flags: {}", boot_record()->flags);
-        dbgln("FATFS: fat_version: {}", boot_record()->fat_version);
-        dbgln("FATFS: root_directory_cluster: {}", boot_record()->root_directory_cluster);
-        dbgln("FATFS: fs_info_sector: {}", boot_record()->fs_info_sector);
-        dbgln("FATFS: backup_boot_sector: {}", boot_record()->backup_boot_sector);
-        dbgln("FATFS: drive_number: {}", boot_record()->drive_number);
-        dbgln("FATFS: volume_id: {}", boot_record()->volume_id);
-    }
-
-    if (boot_record()->signature != signature_1 && boot_record()->signature != signature_2) {
-        dbgln("FATFS: Invalid signature");
-        return EINVAL;
-    }
-
-    m_logical_block_size = boot_record()->bytes_per_sector;
-    set_block_size(m_logical_block_size);
-
-    u32 root_directory_sectors = ((boot_record()->root_directory_entry_count * sizeof(FATEntry)) + (m_logical_block_size - 1)) / m_logical_block_size;
-    m_first_data_sector = boot_record()->reserved_sector_count + (boot_record()->fat_count * boot_record()->sectors_per_fat) + root_directory_sectors;
-
-    TRY(BlockBasedFileSystem::initialize_while_locked());
-
-    FATEntry root_entry {};
-
-    root_entry.first_cluster_low = boot_record()->root_directory_cluster & 0xFFFF;
-    root_entry.first_cluster_high = boot_record()->root_directory_cluster >> 16;
-
-    root_entry.attributes = FATAttributes::Directory;
-    m_root_inode = TRY(FATInode::create(*this, root_entry));
-
-    return {};
-}
-
-Inode& FATFS::root_inode()
-{
-    return *m_root_inode;
-}
-
-BlockBasedFileSystem::BlockIndex FATFS::first_block_of_cluster(u32 cluster) const
-{
-    return ((cluster - first_data_cluster) * boot_record()->sectors_per_cluster) + m_first_data_sector;
-}
-
 ErrorOr<NonnullLockRefPtr<FATInode>> FATInode::create(FATFS& fs, FATEntry entry, Vector<FATLongFileNameEntry> const& lfn_entries)
 {
     auto filename = TRY(compute_filename(entry, lfn_entries));
diff --git a/Kernel/FileSystem/FATFS/Inode.h b/Kernel/FileSystem/FATFS/Inode.h
new file mode 100644
index 0000000000..58803190d4
--- /dev/null
+++ b/Kernel/FileSystem/FATFS/Inode.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2022, Undefine <undefine@undefine.pl>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/OwnPtr.h>
+#include <AK/RefPtr.h>
+#include <Kernel/FileSystem/FATFS/Definitions.h>
+#include <Kernel/FileSystem/FATFS/FileSystem.h>
+#include <Kernel/FileSystem/Inode.h>
+#include <Kernel/KBuffer.h>
+#include <Kernel/KString.h>
+
+namespace Kernel {
+
+class FATInode final : public Inode {
+    friend FATFS;
+
+public:
+    virtual ~FATInode() override = default;
+
+    static ErrorOr<NonnullLockRefPtr<FATInode>> create(FATFS&, FATEntry, Vector<FATLongFileNameEntry> const& = {});
+
+    FATFS& fs() { return static_cast<FATFS&>(Inode::fs()); }
+    FATFS const& fs() const { return static_cast<FATFS const&>(Inode::fs()); }
+
+private:
+    FATInode(FATFS&, FATEntry, NonnullOwnPtr<KString> filename);
+
+    static constexpr u32 no_more_clusters = 0x0FFFFFF8;
+    static constexpr u32 cluster_number_mask = 0x0FFFFFFF;
+
+    static constexpr u8 end_entry_byte = 0x00;
+    static constexpr u8 unused_entry_byte = 0xE5;
+
+    static constexpr u8 lfn_entry_text_termination = 0xFF;
+
+    static constexpr u16 first_fat_year = 1980;
+
+    static constexpr u8 normal_filename_length = 8;
+    static constexpr u8 normal_extension_length = 3;
+
+    static ErrorOr<NonnullOwnPtr<KString>> compute_filename(FATEntry&, Vector<FATLongFileNameEntry> const& = {});
+    static StringView byte_terminated_string(StringView, u8);
+    static time_t fat_date_time(FATPackedDate date, FATPackedTime time);
+
+    ErrorOr<Vector<BlockBasedFileSystem::BlockIndex>> compute_block_list();
+    ErrorOr<NonnullOwnPtr<KBuffer>> read_block_list();
+    ErrorOr<LockRefPtr<FATInode>> traverse(Function<ErrorOr<bool>(LockRefPtr<FATInode>)> callback);
+    u32 first_cluster() const;
+
+    // ^Inode
+    virtual ErrorOr<size_t> write_bytes_locked(off_t, size_t, UserOrKernelBuffer const& data, OpenFileDescription*) override;
+    virtual ErrorOr<size_t> read_bytes_locked(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
+
+    virtual InodeMetadata metadata() const override;
+    virtual ErrorOr<void> traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const override;
+    virtual ErrorOr<NonnullLockRefPtr<Inode>> lookup(StringView name) override;
+    virtual ErrorOr<NonnullLockRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
+    virtual ErrorOr<void> add_child(Inode&, StringView name, mode_t) override;
+    virtual ErrorOr<void> remove_child(StringView name) override;
+    virtual ErrorOr<void> chmod(mode_t) override;
+    virtual ErrorOr<void> chown(UserID, GroupID) override;
+    virtual ErrorOr<void> flush_metadata() override;
+
+    Vector<BlockBasedFileSystem::BlockIndex> m_block_list;
+    FATEntry m_entry;
+    NonnullOwnPtr<KString> m_filename;
+    InodeMetadata m_metadata;
+};
+
+}
diff --git a/Kernel/FileSystem/FATFileSystem.h b/Kernel/FileSystem/FATFileSystem.h
deleted file mode 100644
index 61cc30d437..0000000000
--- a/Kernel/FileSystem/FATFileSystem.h
+++ /dev/null
@@ -1,201 +0,0 @@
-/*
- * Copyright (c) 2022, Undefine <undefine@undefine.pl>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include <AK/OwnPtr.h>
-#include <AK/RefPtr.h>
-#include <AK/Types.h>
-#include <Kernel/FileSystem/BlockBasedFileSystem.h>
-#include <Kernel/FileSystem/Inode.h>
-#include <Kernel/KBuffer.h>
-
-namespace Kernel {
-
-struct [[gnu::packed]] FAT32BootRecord {
-    u8 boot_jump[3];
-    char oem_identifier[8];
-    u16 bytes_per_sector;
-    u8 sectors_per_cluster;
-    u16 reserved_sector_count;
-    u8 fat_count;
-    u16 root_directory_entry_count;
-    u16 unused1;
-    u8 media_descriptor_type;
-    u16 unused2;
-    u16 sectors_per_track;
-    u16 head_count;
-    u32 hidden_sector_count;
-    u32 sector_count;
-    u32 sectors_per_fat;
-    u16 flags;
-    u16 fat_version;
-    u32 root_directory_cluster;
-    u16 fs_info_sector;
-    u16 backup_boot_sector;
-    u8 unused3[12];
-    u8 drive_number;
-    u8 unused4;
-    u8 signature;
-    u32 volume_id;
-    char volume_label_string[11];
-    char system_identifier_string[8];
-};
-static_assert(sizeof(FAT32BootRecord) == 90);
-
-enum class FATAttributes : u8 {
-    ReadOnly = 0x01,
-    Hidden = 0x02,
-    System = 0x04,
-    VolumeID = 0x08,
-    Directory = 0x10,
-    Archive = 0x20,
-    LongFileName = 0x0F
-};
-
-AK_ENUM_BITWISE_OPERATORS(FATAttributes);
-
-union FATPackedTime {
-    u16 value;
-    struct {
-        u16 second : 5;
-        u16 minute : 6;
-        u16 hour : 5;
-    };
-};
-static_assert(sizeof(FATPackedTime) == 2);
-
-union FATPackedDate {
-    u16 value;
-    struct {
-        u16 day : 5;
-        u16 month : 4;
-        u16 year : 7;
-    };
-};
-static_assert(sizeof(FATPackedDate) == 2);
-
-struct [[gnu::packed]] FATEntry {
-    char filename[8];
-    char extension[3];
-    FATAttributes attributes;
-    u8 unused1;
-    u8 creation_time_seconds;
-    FATPackedTime creation_time;
-    FATPackedDate creation_date;
-    FATPackedDate last_accessed_date;
-    u16 first_cluster_high;
-    FATPackedTime modification_time;
-    FATPackedDate modification_date;
-    u16 first_cluster_low;
-    u32 file_size;
-};
-static_assert(sizeof(FATEntry) == 32);
-
-struct [[gnu::packed]] FATLongFileNameEntry {
-    u8 entry_index;
-    u16 characters1[5];
-    FATAttributes attributes;
-    u8 entry_type;
-    u8 checksum;
-    u16 characters2[6];
-    u16 zero;
-    u16 characters3[2];
-};
-static_assert(sizeof(FATLongFileNameEntry) == 32);
-
-class FATInode;
-
-class FATFS final : public BlockBasedFileSystem {
-    friend FATInode;
-
-public:
-    static ErrorOr<NonnullLockRefPtr<FileSystem>> try_create(OpenFileDescription&);
-
-    virtual ~FATFS() override = default;
-    virtual StringView class_name() const override { return "FATFS"sv; }
-    virtual Inode& root_inode() override;
-
-private:
-    virtual ErrorOr<void> initialize_while_locked() override;
-    virtual bool is_initialized_while_locked() override;
-    // FIXME: This is not a proper way to clear last mount of a FAT filesystem,
-    // but for now we simply have no other way to properly do it.
-    virtual ErrorOr<void> prepare_to_clear_last_mount() override { return {}; }
-
-    FATFS(OpenFileDescription&);
-
-    static constexpr u8 signature_1 = 0x28;
-    static constexpr u8 signature_2 = 0x29;
-
-    static constexpr u32 first_data_cluster = 2;
-
-    FAT32BootRecord const* boot_record() const { return reinterpret_cast<FAT32BootRecord const*>(m_boot_record->data()); };
-
-    BlockBasedFileSystem::BlockIndex first_block_of_cluster(u32 cluster) const;
-
-    OwnPtr<KBuffer> m_boot_record;
-    LockRefPtr<FATInode> m_root_inode;
-    u32 m_first_data_sector;
-};
-
-class FATInode final : public Inode {
-    friend FATFS;
-
-public:
-    virtual ~FATInode() override = default;
-
-    static ErrorOr<NonnullLockRefPtr<FATInode>> create(FATFS&, FATEntry, Vector<FATLongFileNameEntry> const& = {});
-
-    FATFS& fs() { return static_cast<FATFS&>(Inode::fs()); }
-    FATFS const& fs() const { return static_cast<FATFS const&>(Inode::fs()); }
-
-private:
-    FATInode(FATFS&, FATEntry, NonnullOwnPtr<KString> filename);
-
-    static constexpr u32 no_more_clusters = 0x0FFFFFF8;
-    static constexpr u32 cluster_number_mask = 0x0FFFFFFF;
-
-    static constexpr u8 end_entry_byte = 0x00;
-    static constexpr u8 unused_entry_byte = 0xE5;
-
-    static constexpr u8 lfn_entry_text_termination = 0xFF;
-
-    static constexpr u16 first_fat_year = 1980;
-
-    static constexpr u8 normal_filename_length = 8;
-    static constexpr u8 normal_extension_length = 3;
-
-    static ErrorOr<NonnullOwnPtr<KString>> compute_filename(FATEntry&, Vector<FATLongFileNameEntry> const& = {});
-    static StringView byte_terminated_string(StringView, u8);
-    static time_t fat_date_time(FATPackedDate date, FATPackedTime time);
-
-    ErrorOr<Vector<BlockBasedFileSystem::BlockIndex>> compute_block_list();
-    ErrorOr<NonnullOwnPtr<KBuffer>> read_block_list();
-    ErrorOr<LockRefPtr<FATInode>> traverse(Function<ErrorOr<bool>(LockRefPtr<FATInode>)> callback);
-    u32 first_cluster() const;
-
-    // ^Inode
-    virtual ErrorOr<size_t> write_bytes_locked(off_t, size_t, UserOrKernelBuffer const& data, OpenFileDescription*) override;
-    virtual ErrorOr<size_t> read_bytes_locked(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const override;
-
-    virtual InodeMetadata metadata() const override;
-    virtual ErrorOr<void> traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)>) const override;
-    virtual ErrorOr<NonnullLockRefPtr<Inode>> lookup(StringView name) override;
-    virtual ErrorOr<NonnullLockRefPtr<Inode>> create_child(StringView name, mode_t, dev_t, UserID, GroupID) override;
-    virtual ErrorOr<void> add_child(Inode&, StringView name, mode_t) override;
-    virtual ErrorOr<void> remove_child(StringView name) override;
-    virtual ErrorOr<void> chmod(mode_t) override;
-    virtual ErrorOr<void> chown(UserID, GroupID) override;
-    virtual ErrorOr<void> flush_metadata() override;
-
-    Vector<BlockBasedFileSystem::BlockIndex> m_block_list;
-    FATEntry m_entry;
-    NonnullOwnPtr<KString> m_filename;
-    InodeMetadata m_metadata;
-};
-
-}