Kernel: Start work on adding support for new filesystems

Old code tried to create ext2 filesystem from all devices.

kernel/include/kernel/FS/Ext2/FileSystem.h

@@ -45,7 +45,8 @@ namespace Kernel
 		};
 
 	public:
-		static BAN::ErrorOr<Ext2FS*> create(BAN::RefPtr<BlockDevice>);
+		static BAN::ErrorOr<bool> probe(BAN::RefPtr<BlockDevice>);
+		static BAN::ErrorOr<BAN::RefPtr<Ext2FS>> create(BAN::RefPtr<BlockDevice>);
 
 		virtual BAN::RefPtr<Inode> root_inode() override { return m_root_inode; }
 
@@ -120,6 +121,7 @@ namespace Kernel
 		Ext2::Superblock m_superblock;
 
 		friend class Ext2Inode;
+		friend class BAN::RefPtr<Ext2FS>;
 	};
 
 }

kernel/include/kernel/FS/FileSystem.h

@@ -1,14 +1,18 @@
 #pragma once
 
+#include <kernel/Device/Device.h>
 #include <kernel/FS/Inode.h>
 
 namespace Kernel
 {
 
-	class FileSystem
+	class FileSystem : public BAN::RefCounted<FileSystem>
 	{
 	public:
 		virtual ~FileSystem() {}
+
+		static BAN::ErrorOr<BAN::RefPtr<FileSystem>> from_block_device(BAN::RefPtr<BlockDevice>);
+
 		virtual BAN::RefPtr<Inode> root_inode() = 0;
 
 		virtual dev_t dev() const = 0;

kernel/include/kernel/FS/VirtualFileSystem.h

@@ -13,7 +13,6 @@ namespace Kernel
 	public:
 		static void initialize(BAN::StringView);
 		static VirtualFileSystem& get();
-		virtual ~VirtualFileSystem() {};
 
 		virtual BAN::RefPtr<Inode> root_inode() override { return m_root_fs->root_inode(); }
 
@@ -21,7 +20,7 @@ namespace Kernel
 		virtual dev_t dev() const override { return 0; }
 
 		BAN::ErrorOr<void> mount(const Credentials&, BAN::StringView, BAN::StringView);
-		BAN::ErrorOr<void> mount(const Credentials&, FileSystem*, BAN::StringView);
+		BAN::ErrorOr<void> mount(const Credentials&, BAN::RefPtr<FileSystem>, BAN::StringView);
 
 		struct File
 		{
@@ -35,16 +34,18 @@ namespace Kernel
 
 		struct MountPoint
 		{
+			BAN::RefPtr<FileSystem> target;
 			File host;
-			FileSystem* target;
 		};
 		MountPoint* mount_from_host_inode(BAN::RefPtr<Inode>);
 		MountPoint* mount_from_root_inode(BAN::RefPtr<Inode>);
 
 	private:
 		Mutex					m_mutex;
-		FileSystem*				m_root_fs = nullptr;
+		BAN::RefPtr<FileSystem>	m_root_fs;
 		BAN::Vector<MountPoint>	m_mount_points;
+
+		friend class BAN::RefPtr<VirtualFileSystem>;
 	};
 
 }