Kernel: Add basic mounting to VFS.

disk.sh

@@ -15,6 +15,10 @@ sed -e 's/\s*\([-\+[:alnum:]]*\).*/\1/' << EOF | fdisk $DISK_NAME
         # default (from the beginning of the disk)
   +1MiB # bios boot partiton size
   n		# new partition
+  3		# partition number 3
+		# default (right after bios boot partition)
+  +10Mib# partition size
+  n     # new partition
   2     # partition number 2
         # default (right after bios boot partition)
 		# default (to the end of disk)
@@ -26,6 +30,9 @@ sed -e 's/\s*\([-\+[:alnum:]]*\).*/\1/' << EOF | fdisk $DISK_NAME
   20    # Linux filesystem
   x		# expert menu
   n		# partition name
+  3		# ... of partition 3
+  mount-test
+  n		# partition name
   2		# ... of partition 2
   banan-root
   r		# back to main menu
@@ -37,6 +44,7 @@ sudo partprobe $LOOP_DEV
 
 PARTITION1=${LOOP_DEV}p1
 PARTITION2=${LOOP_DEV}p2
+PARTITION3=${LOOP_DEV}p3
 
 sudo mkfs.ext2 $PARTITION2
 
@@ -64,4 +72,10 @@ menuentry "banan-os (no apic, no serial)" {
 ' | sudo tee ${MOUNT_DIR}/boot/grub/grub.cfg
 
 sudo umount $MOUNT_DIR
+
+sudo mkfs.ext2 $PARTITION3
+sudo mount $PARTITION3 $MOUNT_DIR
+echo 'hello' | sudo tee ${MOUNT_DIR}/hello.txt
+sudo umount $MOUNT_DIR
+
 sudo losetup -d $LOOP_DEV

kernel/Makefile

@@ -42,6 +42,7 @@ kernel/CPUID.o					\
 kernel/Debug.o					\
 kernel/Font.o					\
 kernel/FS/Ext2.o				\
+kernel/FS/Inode.o				\
 kernel/FS/VirtualFileSystem.o	\
 kernel/Input.o					\
 kernel/InterruptController.o	\

kernel/include/kernel/FS/Ext2.h

@@ -132,12 +132,14 @@ namespace Kernel
 		virtual BAN::StringView name() const override { return m_name; }
 
 		virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) override;
-		virtual BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> directory_inodes() override;
-		virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find(BAN::StringView) override;
 
 		virtual Type type() const override { return Type::Ext2; }
 		virtual bool operator==(const Inode& other) const override;
 
+	protected:
+		virtual BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> directory_inodes_impl() override;
+		virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find_impl(BAN::StringView) override;
+
 	private:
 		BAN::ErrorOr<uint32_t> data_block_index(uint32_t);
 
@@ -170,7 +172,7 @@ namespace Kernel
 	public:	
 		static BAN::ErrorOr<Ext2FS*> create(StorageDevice::Partition&);
 
-		virtual const BAN::RefPtr<Inode> root_inode() const override { return m_root_inode; }
+		virtual BAN::RefPtr<Inode> root_inode() override { return m_root_inode; }
 
 	private:
 		Ext2FS(StorageDevice::Partition& partition)

kernel/include/kernel/FS/FileSystem.h

@@ -9,7 +9,7 @@ namespace Kernel
 	class FileSystem
 	{
 	public:
-		virtual const BAN::RefPtr<Inode> root_inode() const = 0;
+		virtual BAN::RefPtr<Inode> root_inode() = 0;
 	};
 
 }

kernel/include/kernel/FS/Inode.h

@@ -1,9 +1,8 @@
 #pragma once
 
-#include <BAN/ForwardList.h>
 #include <BAN/Memory.h>
-
+#include <BAN/String.h>
-#include <stdint.h>
+#include <BAN/Vector.h>
 
 namespace Kernel
 {
@@ -37,7 +36,6 @@ namespace Kernel
 
 		enum class Type
 		{
-			General,
 			Ext2,
 		};
 
@@ -55,12 +53,17 @@ namespace Kernel
 
 		virtual BAN::StringView name() const = 0;
 
-		virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) = 0;
+		BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> directory_inodes();
-		virtual BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> directory_inodes() = 0;
+		BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find(BAN::StringView);
-		virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find(BAN::StringView) = 0;
 
-		virtual Type type() const { return Type::General; }
+		virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) = 0;
+
+		virtual Type type() const = 0;
 		virtual bool operator==(const Inode&) const = 0;
+
+	protected:
+		virtual BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> directory_inodes_impl() = 0;
+		virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find_impl(BAN::StringView) = 0;
 	};
 
 }

kernel/include/kernel/FS/VirtualFileSystem.h

@@ -2,6 +2,7 @@
 
 #include <BAN/HashMap.h>
 #include <BAN/String.h>
+#include <BAN/StringView.h>
 #include <kernel/FS/FileSystem.h>
 #include <kernel/Storage/StorageController.h>
 
@@ -15,7 +16,9 @@ namespace Kernel
 		static VirtualFileSystem& get();
 		virtual ~VirtualFileSystem() {};
 
-		virtual const BAN::RefPtr<Inode> root_inode() const override  { return m_root_inode; }
+		virtual BAN::RefPtr<Inode> root_inode() override  { return m_root_inode; }
+
+		BAN::ErrorOr<void> mount_test();
 
 		struct File
 		{
@@ -24,12 +27,20 @@ namespace Kernel
 		};
 		BAN::ErrorOr<File> file_from_absolute_path(BAN::StringView);
 
+		struct MountPoint
+		{
+			BAN::RefPtr<Inode> inode;
+			FileSystem* target;
+		};
+		const BAN::Vector<MountPoint>& mount_points() const { return m_mount_points; }
+
 	private:
 		VirtualFileSystem() = default;
 		BAN::ErrorOr<void> initialize_impl();
 
 	private:
 		BAN::RefPtr<Inode>				m_root_inode;
+		BAN::Vector<MountPoint>			m_mount_points;
 		BAN::Vector<StorageController*>	m_storage_controllers;
 	};
 

kernel/kernel/FS/Ext2.cpp

@@ -263,7 +263,7 @@ namespace Kernel
 		return count;
 	}
 
-	BAN::ErrorOr<BAN::RefPtr<Inode>> Ext2Inode::directory_find(BAN::StringView file_name)
+	BAN::ErrorOr<BAN::RefPtr<Inode>> Ext2Inode::directory_find_impl(BAN::StringView file_name)
 	{
 		if (!ifdir())
 			return BAN::Error::from_errno(ENOTDIR);
@@ -307,45 +307,42 @@ namespace Kernel
 		return BAN::Error::from_errno(ENOENT);
 	}
 
-	BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> Ext2Inode::directory_inodes()
+	BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> Ext2Inode::directory_inodes_impl()
 	{
 		if (!ifdir())
 			return BAN::Error::from_errno(ENOTDIR);
 
-		struct directory_info
+		uint32_t data_block_count = m_inode.blocks / (2 << m_fs.superblock().log_block_size);
-		{
+		
 		BAN::Vector<BAN::RefPtr<Inode>> inodes;
-			Ext2FS* fs;
-		};
 
-		directory_info info;
+		for (uint32_t i = 0; i < data_block_count; i++)
-		info.inodes = {};
-		info.fs = &m_fs;
-
-		block_callback_t function =
-			[](const BAN::Vector<uint8_t>& block_data, void* info_) -> BAN::ErrorOr<bool>
 		{
-				directory_info& info = *(directory_info*)info_;
+			auto data_block_index_or_error = data_block_index(i);
+			if (data_block_index_or_error.is_error())
+			{
+				dprintln("{}", data_block_index_or_error.error());
+				continue;	
+			}
 
-				uintptr_t block_data_end = (uintptr_t)block_data.data() + block_data.size();
+			auto block_data = TRY(m_fs.read_block(data_block_index_or_error.value()));
-				uintptr_t entry_addr = (uintptr_t)block_data.data();
+			
+			uint8_t* block_data_end = block_data.data() + block_data.size();
+			uint8_t* entry_addr = block_data.data();
 			while (entry_addr < block_data_end)
 			{
 				Ext2::LinkedDirectoryEntry* entry = (Ext2::LinkedDirectoryEntry*)entry_addr;
 				if (entry->inode)
 				{
 					auto entry_name = BAN::StringView(entry->name, entry->name_len);
-						auto inode = TRY(Ext2Inode::create(*info.fs, entry->inode, entry_name));
+					auto inode = TRY(Ext2Inode::create(m_fs, entry->inode, entry_name));
-						TRY(info.inodes.push_back(inode));
+					TRY(inodes.push_back(inode));
 				}
 				entry_addr += entry->rec_len;
 			}
-				return true;
+		}
-			};
 
-		TRY(for_each_block(function, &info));
+		return inodes;
-
-		return info.inodes;
 	}
 
 	bool Ext2Inode::operator==(const Inode& other) const

kernel/kernel/FS/Inode.cpp

@@ -0,0 +1,27 @@
+#include <BAN/StringView.h>
+#include <kernel/FS/Inode.h>
+#include <kernel/FS/VirtualFileSystem.h>
+
+namespace Kernel
+{
+
+	
+	BAN::ErrorOr<BAN::Vector<BAN::RefPtr<Inode>>> Inode::directory_inodes()
+	{
+		for (const auto& mount : VirtualFileSystem::get().mount_points())
+			if (*mount.inode == *this)
+				return mount.target->root_inode()->directory_inodes_impl();
+		return directory_inodes_impl();
+	}
+
+	BAN::ErrorOr<BAN::RefPtr<Inode>> Inode::directory_find(BAN::StringView name)
+	{
+		if (name == ".."sv)
+			return directory_find_impl(name);
+		for (const auto& mount : VirtualFileSystem::get().mount_points())
+			if (*mount.inode == *this)
+				return mount.target->root_inode()->directory_find_impl(name);
+		return directory_find_impl(name);
+	}
+
+}

kernel/kernel/FS/VirtualFileSystem.cpp

@@ -115,6 +115,32 @@ namespace Kernel
 		return {};
 	}
 
+	BAN::ErrorOr<void> VirtualFileSystem::mount_test()
+	{
+		auto mount = TRY(root_inode()->directory_find("mnt"sv));
+		if (!mount->ifdir())
+			return BAN::Error::from_errno(ENOTDIR);
+		if (TRY(mount->directory_inodes()).size() > 2)
+			return BAN::Error::from_errno(ENOTEMPTY);
+
+		for (auto* controller : m_storage_controllers)
+		{
+			for (auto* device : controller->devices())
+			{
+				for (auto& partition : device->partitions())
+				{
+					if (partition.name() == "mount-test"sv)
+					{
+						auto ext2fs = TRY(Ext2FS::create(partition));
+						TRY(m_mount_points.push_back({ mount, ext2fs }));
+						return {};
+					}
+				}
+			}
+		}
+		return {};
+	}
+
 	BAN::ErrorOr<VirtualFileSystem::File> VirtualFileSystem::file_from_absolute_path(BAN::StringView path)
 	{
 		ASSERT(path.front() == '/');

kernel/kernel/kernel.cpp

@@ -195,6 +195,8 @@ void init2(void* tty1_ptr)
 	TTY* tty1 = (TTY*)tty1_ptr;
 
 	MUST(VirtualFileSystem::initialize());
+	if (auto res = VirtualFileSystem::get().mount_test(); res.is_error())
+		dwarnln("{}", res.error());
 
 	MUST(Process::create_kernel(
 		[](void* tty1)