automatically detect the mounted file system type by trial-and-error

4 files changed, 30 insertions, 11 deletions

diff --git a/kernel/include/kernel/filesystem/filesystem.hpp b/kernel/include/kernel/filesystem/filesystem.hpp
index 1d86178..05f96dc 100644
--- a/kernel/include/kernel/filesystem/filesystem.hpp
+++ b/kernel/include/kernel/filesystem/filesystem.hpp
@@ -2,6 +2,7 @@
 #define TEACH_OS_KERNEL_FILESYSTEM_FILESYSTEM_HPP
 
 #include "kapi/devices/device.hpp"
+
 #include "kernel/filesystem/inode.hpp"
 
 #include <kstd/memory>
@@ -15,7 +16,7 @@ namespace kernel::filesystem
   {
     virtual ~filesystem() = default;
 
-    virtual auto mount(kstd::shared_ptr<kapi::devices::device> const & device) -> int;
+    auto static mount(kstd::shared_ptr<kapi::devices::device> const & device) -> kstd::shared_ptr<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 &;
diff --git a/kernel/src/filesystem/filesystem.cpp b/kernel/src/filesystem/filesystem.cpp
index 0ac9cf8..e0c760f 100644
--- a/kernel/src/filesystem/filesystem.cpp
+++ b/kernel/src/filesystem/filesystem.cpp
@@ -1,20 +1,41 @@
 #include "kernel/filesystem/filesystem.hpp"
 
 #include "kapi/devices/device.hpp"
+#include "kapi/system.hpp"
+
+#include "kernel/filesystem/ext2/filesystem.hpp"
 #include "kernel/filesystem/inode.hpp"
 
 #include <kstd/memory>
 
+#include <array>
+
 namespace kernel::filesystem
 {
-  auto filesystem::mount(kstd::shared_ptr<kapi::devices::device> const & device) -> int
+  namespace
+  {
+    constexpr auto static filesystem_factories = std::array{
+      []() { return kstd::make_shared<ext2::filesystem>(); },
+    };
+  }  // namespace
+
+  auto filesystem::mount(kstd::shared_ptr<kapi::devices::device> const & device) -> kstd::shared_ptr<filesystem>
   {
     if (!device)
     {
-      return -1;  // TODO BA-FS26 panic or errorcode?
+      kapi::system::panic("[FILESYSTEM] cannot mount filesystem: device is null.");
     }
-    m_device = device;
-    return 0;
+
+    for (auto & factory : filesystem_factories)
+    {
+      auto fs = factory();
+      if (fs->mount(device) == 0)
+      {
+        return fs;
+      }
+    }
+
+    kapi::system::panic("[FILESYSTEM] cannot mount filesystem: no suitable filesystem found on device.");
   }
 
   auto filesystem::root_inode() const -> kstd::shared_ptr<inode> const &
diff --git a/kernel/src/filesystem/vfs.cpp b/kernel/src/filesystem/vfs.cpp
index 06214d2..66aa91e 100644
--- a/kernel/src/filesystem/vfs.cpp
+++ b/kernel/src/filesystem/vfs.cpp
@@ -5,7 +5,6 @@
 #include "kernel/devices/storage/management.hpp"
 #include "kernel/filesystem/dentry.hpp"
 #include "kernel/filesystem/devfs/filesystem.hpp"
-#include "kernel/filesystem/ext2/filesystem.hpp"
 #include "kernel/filesystem/filesystem.hpp"
 #include "kernel/filesystem/mount.hpp"
 #include "kernel/filesystem/open_file_description.hpp"
@@ -46,9 +45,7 @@ namespace kernel::filesystem
     auto storage_mgmt = devices::storage::management::get();
     if (auto boot_device = storage_mgmt.determine_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::filesystem>();
-      boot_root_fs->mount(boot_device);
+      auto boot_root_fs = kernel::filesystem::filesystem::mount(boot_device);
       do_mount_internal("/", root_fs_root_dentry, boot_root_fs);
     }
 
diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp
index b920674..382f12d 100644
--- a/kernel/src/main.cpp
+++ b/kernel/src/main.cpp
@@ -130,9 +130,9 @@ auto test_file_lookup() -> void
     kstd::os::panic("test code failed");
   }
 
-  auto new_filesystem = kstd::make_shared<kernel::filesystem::ext2::filesystem>();
   auto device = storage_mgmt.device_by_major_minor(1, 16);
-  new_filesystem->mount(device);
+  auto new_filesystem = kernel::filesystem::filesystem::mount(device);
+
   if (vfs.do_mount("/a/b", new_filesystem) != 0)
   {
     kstd::os::panic("test code failed");