Kernel: VFS caches currently open inodes

kernel/include/kernel/FS/VirtualFileSystem.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <BAN/HashMap.h>
+#include <BAN/String.h>
 #include <kernel/FS/FileSystem.h>
 #include <kernel/Storage/StorageController.h>
 
@@ -13,7 +15,9 @@ namespace Kernel
 		static VirtualFileSystem& get();
 		virtual ~VirtualFileSystem() {};
 
-		virtual const BAN::RefPtr<Inode> root_inode() const override { return m_root_inode; }
+		virtual const BAN::RefPtr<Inode> root_inode() const override;
+
+		void close_inode(BAN::StringView);
 
 		BAN::ErrorOr<BAN::RefPtr<Inode>> from_absolute_path(BAN::StringView);
 
@@ -22,8 +26,7 @@ namespace Kernel
 		BAN::ErrorOr<void> initialize_impl();
 
 	private:
-		BAN::RefPtr<Inode> m_root_inode;
-
+		BAN::HashMap<BAN::String, BAN::RefPtr<Inode>>	m_open_inodes;
 		BAN::Vector<StorageController*>					m_storage_controllers;
 	};
 

kernel/kernel/FS/VirtualFileSystem.cpp

@@ -93,7 +93,7 @@ namespace Kernel
 				{
 					if (partition.name() == "banan-root"sv)
 					{
-						if (m_root_inode)
+						if (root_inode())
 							dwarnln("multiple root partitions found");
 						else
 						{
@@ -103,32 +103,51 @@ namespace Kernel
 							else
 								// FIXME: We leave a dangling pointer to ext2fs. This might be okay since
 								//        root fs sould probably be always mounted
-								m_root_inode = ext2fs_or_error.release_value()->root_inode();
+								TRY(m_open_inodes.insert("/"sv, ext2fs_or_error.release_value()->root_inode()));
 						}
 					}
 				}
 			}
 		}
 
-		if (m_root_inode.empty())
+		if (!root_inode())
 			derrorln("Could not locate root partition");
 		return {};
 	}
 
+	const BAN::RefPtr<Inode> VirtualFileSystem::root_inode() const
+	{
+		if (!m_open_inodes.contains("/"sv))
+			return nullptr;
+		return m_open_inodes["/"sv];
+	}
+
+	void VirtualFileSystem::close_inode(BAN::StringView path)
+	{
+		ASSERT(m_open_inodes.contains(path));
+
+		// Delete the cached inode, if we are the only one holding a reference to it
+		if (m_open_inodes[path]->ref_count() == 1)
+			m_open_inodes.remove(path);
+	}
+
 	BAN::ErrorOr<BAN::RefPtr<Inode>> VirtualFileSystem::from_absolute_path(BAN::StringView path)
 	{
-		if (path.front() != '/')
-			return BAN::Error::from_c_string("Path must be an absolute path");
+		ASSERT(path.front() == '/');
+		
+		if (m_open_inodes.contains(path))
+			return m_open_inodes[path];
 
 		auto inode = root_inode();
 		if (!inode)
 			return BAN::Error::from_c_string("No root inode available");
 
 		auto path_parts = TRY(path.split('/'));
-		
 		for (BAN::StringView part : path_parts)
 			inode = TRY(inode->directory_find(part));
 		
+		TRY(m_open_inodes.insert(path, inode));
+
 		return inode;
 	}