From 84d4476650b31dbfc52becf2ff65ddce9d31c9ec Mon Sep 17 00:00:00 2001
From: Lukas Oesch <lukasoesch20@gmail.com>
Date: Tue, 24 Mar 2026 23:54:28 +0100
Subject: implement a rootfs to handle / mounts correctly

---
 kernel/include/kernel/filesystem/filesystem.hpp     |  5 -----
 kernel/include/kernel/filesystem/mount.hpp          | 10 +++++++---
 .../kernel/filesystem/rootfs/rootfs_filesystem.hpp  | 21 +++++++++++++++++++++
 .../kernel/filesystem/rootfs/rootfs_inode.hpp       | 19 +++++++++++++++++++
 4 files changed, 47 insertions(+), 8 deletions(-)
 create mode 100644 kernel/include/kernel/filesystem/rootfs/rootfs_filesystem.hpp
 create mode 100644 kernel/include/kernel/filesystem/rootfs/rootfs_inode.hpp

(limited to 'kernel/include')

diff --git a/kernel/include/kernel/filesystem/filesystem.hpp b/kernel/include/kernel/filesystem/filesystem.hpp
index 362242f..e069ced 100644
--- a/kernel/include/kernel/filesystem/filesystem.hpp
+++ b/kernel/include/kernel/filesystem/filesystem.hpp
@@ -2,7 +2,6 @@
 #define TEACH_OS_KERNEL_FILESYSTEM_FILESYSTEM_HPP
 
 #include "kernel/devices/device.hpp"
-#include "kernel/filesystem/dentry.hpp"
 #include "kernel/filesystem/inode.hpp"
 
 #include <kstd/memory>
@@ -20,15 +19,11 @@ namespace filesystem
     virtual auto lookup(kstd::shared_ptr<inode> const & parent, std::string_view name) -> kstd::shared_ptr<inode> = 0;
 
     [[nodiscard]] auto root_inode() const -> kstd::shared_ptr<inode> const &;
-    [[nodiscard]] auto root_dentry() const -> kstd::shared_ptr<dentry> const &;
-
-    auto set_root_dentry(kstd::shared_ptr<dentry> dentry) -> void;
 
   protected:
     kstd::shared_ptr<inode> m_root_inode{};
     kstd::shared_ptr<devices::device> m_device{};
     kstd::vector<kstd::shared_ptr<inode>> m_inodes{};
-    kstd::shared_ptr<dentry> m_root_dentry;
   };
 
 }  // namespace filesystem
diff --git a/kernel/include/kernel/filesystem/mount.hpp b/kernel/include/kernel/filesystem/mount.hpp
index dd47ce7..0cd30b4 100644
--- a/kernel/include/kernel/filesystem/mount.hpp
+++ b/kernel/include/kernel/filesystem/mount.hpp
@@ -10,13 +10,17 @@ namespace filesystem
 {
   struct mount
   {
-    mount(kstd::shared_ptr<dentry> const & mount_dentry, kstd::shared_ptr<filesystem> const & fs);
+    mount(kstd::shared_ptr<dentry> const & mount_dentry, kstd::shared_ptr<dentry> const & root_dentry,
+          kstd::shared_ptr<filesystem> const & fs);
+
+    [[nodiscard]] auto get_mount_dentry() const -> kstd::shared_ptr<dentry>;
+    [[nodiscard]] auto root_dentry() const -> kstd::shared_ptr<dentry> const &;
 
-    [[nodiscard]] auto get_dentry() const -> kstd::shared_ptr<dentry>;
     [[nodiscard]] auto get_filesystem() const -> kstd::shared_ptr<filesystem> const &;
 
   private:
-    kstd::shared_ptr<dentry> m_dentry;
+    kstd::shared_ptr<dentry> m_mount_dentry;
+    kstd::shared_ptr<dentry> m_root_dentry;
     kstd::shared_ptr<filesystem> m_filesystem{};
   };
 }  // namespace filesystem
diff --git a/kernel/include/kernel/filesystem/rootfs/rootfs_filesystem.hpp b/kernel/include/kernel/filesystem/rootfs/rootfs_filesystem.hpp
new file mode 100644
index 0000000..949ac83
--- /dev/null
+++ b/kernel/include/kernel/filesystem/rootfs/rootfs_filesystem.hpp
@@ -0,0 +1,21 @@
+#ifndef TEACH_OS_KERNEL_FILESYSTEM_ROOTFS_ROOTFS_FILESYSTEM_HPP
+#define TEACH_OS_KERNEL_FILESYSTEM_ROOTFS_ROOTFS_FILESYSTEM_HPP
+
+#include "kernel/devices/device.hpp"
+#include "kernel/filesystem/filesystem.hpp"
+#include "kernel/filesystem/inode.hpp"
+
+#include <kstd/memory>
+
+#include <string_view>
+
+namespace filesystem::rootfs
+{
+  struct rootfs_filesystem : filesystem
+  {
+    auto mount(kstd::shared_ptr<devices::device> const & device) -> int override;
+    auto lookup(kstd::shared_ptr<inode> const & parent, std::string_view name) -> kstd::shared_ptr<inode> override;
+  };
+}  // namespace filesystem::rootfs
+
+#endif
diff --git a/kernel/include/kernel/filesystem/rootfs/rootfs_inode.hpp b/kernel/include/kernel/filesystem/rootfs/rootfs_inode.hpp
new file mode 100644
index 0000000..d533e8e
--- /dev/null
+++ b/kernel/include/kernel/filesystem/rootfs/rootfs_inode.hpp
@@ -0,0 +1,19 @@
+#ifndef TEACH_OS_KERNEL_FILESYSTEM_ROOTFS_ROOTFS_INODE_HPP
+#define TEACH_OS_KERNEL_FILESYSTEM_ROOTFS_ROOTFS_INODE_HPP
+
+#include "kernel/filesystem/inode.hpp"
+
+#include <cstddef>
+
+namespace filesystem::rootfs
+{
+  struct rootfs_inode : inode
+  {
+    rootfs_inode();
+
+    auto read(void * buffer, size_t offset, size_t size) const -> size_t override;
+    auto write(void const * buffer, size_t offset, size_t size) -> size_t override;
+  };
+}  // namespace filesystem::rootfs
+
+#endif
-- 
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