6 files changed, 24 insertions, 16 deletions
diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp
index d7c989c..7ee1072 100644
--- a/kernel/src/filesystem/ext2/filesystem.cpp
+++ b/kernel/src/filesystem/ext2/filesystem.cpp
@@ -36,6 +36,10 @@ namespace kernel::filesystem::ext2
     constexpr uint16_t S_IFREG = 0x8000;
     constexpr uint16_t S_IFDIR = 0x4000;
 
+    // Error codes
+    constexpr int INVALID_MAGIC_NUMBER = -1;
+    constexpr int INVALID_ROOT_INODE = -2;
+
     auto S_ISREG(uint16_t mode) -> bool
     {
       return (mode & S_IFMT) == S_IFREG;
@@ -55,7 +59,7 @@ namespace kernel::filesystem::ext2
 
     if (m_superblock.magic != MAGIC_NUMBER)
     {
-      return -1;
+      return INVALID_MAGIC_NUMBER;
     }
 
     auto const block_size = get_block_size();
@@ -70,7 +74,11 @@ namespace kernel::filesystem::ext2
                                               num_block_groups * sizeof(block_group_descriptor));
 
     m_root_inode = read_inode(ROOT_INODE_NUMBER);
-    // TODO BA-FS26 check if root inode is valid and is a directory ??
+
+    if (!m_root_inode || !m_root_inode->is_directory())
+    {
+      return INVALID_ROOT_INODE;
+    }
     return 0;
   }
 
diff --git a/kernel/src/filesystem/ext2/inode.cpp b/kernel/src/filesystem/ext2/inode.cpp
index 7f4cf69..a29bb3b 100644
--- a/kernel/src/filesystem/ext2/inode.cpp
+++ b/kernel/src/filesystem/ext2/inode.cpp
@@ -53,7 +53,7 @@ namespace kernel::filesystem::ext2
 
   auto inode::write(void const * /*buffer*/, size_t /*offset*/, size_t /*size*/) -> size_t
   {
-    // TODO BA-FS26 implement
+    kapi::system::panic("[EXT2] inode::write is not implemented yet");
     return 0;
   }
 }  // namespace kernel::filesystem::ext2
 \ No newline at end of file
diff --git a/kernel/src/filesystem/filesystem.cpp b/kernel/src/filesystem/filesystem.cpp
index 26c57b6..b08b520 100644
--- a/kernel/src/filesystem/filesystem.cpp
+++ b/kernel/src/filesystem/filesystem.cpp
@@ -36,11 +36,12 @@ namespace kernel::filesystem
       }
     }
 
-    kapi::system::panic("[FILESYSTEM] cannot mount filesystem: no suitable filesystem found on device.");
+    return nullptr;
   }
 
   auto filesystem::mount(kstd::shared_ptr<kapi::devices::device> const & device) -> int
   {
+    // TODO BA-FS26 maybe check if device is null and panic here already?
     m_device = device;
     return 0;
   }
diff --git a/kernel/src/filesystem/mount.cpp b/kernel/src/filesystem/mount.cpp
index f9e709c..a6d2f7e 100644
--- a/kernel/src/filesystem/mount.cpp
+++ b/kernel/src/filesystem/mount.cpp
@@ -25,7 +25,7 @@ namespace kernel::filesystem
     }
   }
 
-  auto mount::get_mount_dentry() const -> kstd::shared_ptr<dentry>
+  auto mount::get_mount_dentry() const -> kstd::shared_ptr<dentry> const &
   {
     return m_mount_dentry;
   }
diff --git a/kernel/src/filesystem/mount_table.cpp b/kernel/src/filesystem/mount_table.cpp
index 737434e..195f48a 100644
--- a/kernel/src/filesystem/mount_table.cpp
+++ b/kernel/src/filesystem/mount_table.cpp
@@ -9,7 +9,7 @@
 
 namespace kernel::filesystem
 {
-  void mount_table::add_mount(kstd::shared_ptr<mount> mount)
+  void mount_table::add_mount(kstd::shared_ptr<mount> const & mount)
   {
     m_mounts.push_back(mount);
   }
diff --git a/kernel/src/filesystem/vfs.cpp b/kernel/src/filesystem/vfs.cpp
index f9a051a..2578036 100644
--- a/kernel/src/filesystem/vfs.cpp
+++ b/kernel/src/filesystem/vfs.cpp
@@ -21,6 +21,11 @@ namespace kernel::filesystem
   namespace
   {
     constinit auto static active_vfs = std::optional<vfs>{};
+
+    // Error codes
+    constexpr int INVALID_PATH = -1;
+    constexpr int MOUNT_POINT_NOT_FOUND = -2;
+    constexpr int FILESYSTEM_NULL = -3;
   }  // namespace
 
   auto vfs::init() -> void
@@ -79,18 +84,12 @@ namespace kernel::filesystem
   {
     if (!filesystem)
     {
-      return -1;  // TODO BA-FS26 panic or errorcode?
-    }
-
-    if (path.empty() || path.front() != '/')
-    {
-      return -1;  // TODO BA-FS26 panic or errorcode?
+      return FILESYSTEM_NULL;
     }
 
-    // TODO BA-FS26 better path validation
-    if ((path.size() > 1 && path.back() == '/'))
+    if (path.empty() || path.front() != '/' || (path.size() > 1 && path.back() == '/'))
     {
-      return -1;  // TODO BA-FS26 panic or errorcode?
+      return INVALID_PATH;
     }
 
     if (auto mount_point_dentry = resolve_path(path))
@@ -99,7 +98,7 @@ namespace kernel::filesystem
       return 0;
     }
 
-    return -1;
+    return MOUNT_POINT_NOT_FOUND;
   }
 
   auto vfs::do_mount_internal(std::string_view path, kstd::shared_ptr<dentry> const & mount_point_dentry,