implement a rootfs to handle / mounts correctly

1 files changed, 29 insertions, 14 deletions

diff --git a/kernel/src/filesystem/vfs.cpp b/kernel/src/filesystem/vfs.cpp
index c8e5bc5..1c4dd8b 100644
--- a/kernel/src/filesystem/vfs.cpp
+++ b/kernel/src/filesystem/vfs.cpp
@@ -10,6 +10,7 @@
 #include "kernel/filesystem/filesystem.hpp"
 #include "kernel/filesystem/mount.hpp"
 #include "kernel/filesystem/open_file_description.hpp"
+#include "kernel/filesystem/rootfs/rootfs_filesystem.hpp"
 
 #include <kstd/memory>
 
@@ -38,16 +39,20 @@ namespace filesystem
 
   auto vfs::init_internal() -> void
   {
+    auto virtual_fs = kstd::make_shared<rootfs::rootfs_filesystem>();
+    virtual_fs->mount(nullptr);
+
+    auto virtual_root_dentry = kstd::make_shared<dentry>(nullptr, virtual_fs->root_inode(), "/");
+    m_mount_table.add_mount(kstd::make_shared<mount>(nullptr, virtual_root_dentry, virtual_fs));
+
     auto storage_mgmt = devices::storage::storage_management::get();
     if (auto boot_device = storage_mgmt.determine_boot_device())
     {
-      auto root_fs = kstd::make_shared<ext2::ext2_filesystem>();
-      root_fs->mount(boot_device);
+      // TODO BA-FS26 detect fs type from boot device and load corresponding fs, for now just assume ext2
+      auto boot_root_fs = kstd::make_shared<ext2::ext2_filesystem>();
+      boot_root_fs->mount(boot_device);
 
-      auto root_dentry = kstd::make_shared<dentry>(nullptr, root_fs->root_inode(), "/");
-      root_fs->set_root_dentry(root_dentry);
-
-      m_mount_table.add_mount(kstd::make_shared<mount>(nullptr, root_fs));
+      do_mount("/", boot_root_fs);
 
       // TODO BA-FS26 use do_mount when tempdevfs is implemented -> just call /dev/ with all devices in devtempfs
       std::ranges::for_each(storage_mgmt.all_controllers(), [&](auto controller) {
@@ -102,10 +107,10 @@ namespace filesystem
     {
       // TODO BA-FS26 check if mount point is already mounted and handle it (unmount old fs, fail, etc.)
 
+      auto new_fs_root = kstd::make_shared<dentry>(mount_dentry, filesystem->root_inode());
+      auto new_mount = kstd::make_shared<mount>(mount_dentry, new_fs_root, filesystem);
+      m_mount_table.add_mount(new_mount);
       mount_dentry->set_flag(dentry::dentry_flags::dcache_mounted);
-      m_mount_table.add_mount(kstd::make_shared<mount>(mount_dentry, filesystem));
-
-      filesystem->set_root_dentry(kstd::make_shared<dentry>(mount_dentry->get_parent(), filesystem->root_inode()));
 
       return 0;
     }
@@ -153,20 +158,30 @@ namespace filesystem
         kapi::system::panic("[FILESYSTEM] no root mount found.");
       }
 
-      auto current_dentry = root_mount->get_dentry();
+      auto current_dentry = root_mount->root_dentry();
       auto current_fs = root_mount->get_filesystem();
 
+      while (current_dentry->has_flag(dentry::dentry_flags::dcache_mounted))
+      {
+        auto mnt = m_mount_table.find_mount_by_dentry(current_dentry);
+        if (!mnt)
+          kapi::system::panic("[FILESYSTEM] dcache_mounted set but no covering mount found.");
+        current_dentry = mnt->root_dentry();
+        current_fs = mnt->get_filesystem();
+      }
+
       auto path_parts =
           std::views::split(path, '/') | std::views::filter([](auto const & part) { return !part.empty(); });
       for (auto const & part : path_parts)
       {
-        auto next_dentry = current_dentry->find_child(std::string_view{part});
+        std::string_view part_view{part};
+        auto next_dentry = current_dentry->find_child(part_view);
 
         if (!next_dentry)
         {
-          if (auto found_inode = current_fs->lookup(current_dentry->get_inode(), std::string_view{part}))
+          if (auto found_inode = current_fs->lookup(current_dentry->get_inode(), part_view))
           {
-            next_dentry = kstd::make_shared<dentry>(current_dentry, found_inode, std::string_view{part});
+            next_dentry = kstd::make_shared<dentry>(current_dentry, found_inode, part_view);
             current_dentry->add_child(next_dentry);
           }
           else
@@ -179,7 +194,7 @@ namespace filesystem
         {
           auto found_mount = m_mount_table.find_mount_by_dentry(next_dentry);
           current_fs = found_mount->get_filesystem();
-          current_dentry = current_fs->root_dentry();
+          current_dentry = found_mount->root_dentry();
         }
         else
         {