From 61d29a288334960cd9f43df91e4fd632a7f6ad66 Mon Sep 17 00:00:00 2001
From: Marcel Braun <marcel.braun@ost.ch>
Date: Mon, 25 May 2026 11:13:18 +0200
Subject: Increase reference count of source_mount when one of its files is
 mounted somewhere

---
 kernel/include/kernel/filesystem/mount.hpp | 13 ++++++++++---
 kernel/include/kernel/filesystem/vfs.hpp   |  7 +++----
 2 files changed, 13 insertions(+), 7 deletions(-)

(limited to 'kernel/include')

diff --git a/kernel/include/kernel/filesystem/mount.hpp b/kernel/include/kernel/filesystem/mount.hpp
index 4ce374f..6c0c5b9 100644
--- a/kernel/include/kernel/filesystem/mount.hpp
+++ b/kernel/include/kernel/filesystem/mount.hpp
@@ -28,7 +28,8 @@ namespace kernel::filesystem
     @param parent_mount The parent mount that this mount is attached beneath.
     */
     mount(kstd::shared_ptr<dentry> const & mount_dentry, kstd::shared_ptr<dentry> const & root_dentry,
-          kstd::shared_ptr<filesystem> const & fs, kstd::shared_ptr<mount> const & parent_mount);
+          kstd::shared_ptr<filesystem> const & fs, kstd::shared_ptr<mount> const & parent_mount,
+          kstd::shared_ptr<mount> const & source_mount);
 
     /**
     @brief Get the dentry where the filesystem is mounted.
@@ -55,6 +56,11 @@ namespace kernel::filesystem
     */
     [[nodiscard]] auto parent_mount() const -> kstd::shared_ptr<mount> const &;
 
+    /**
+    @brief Get the source mount where this mount originates from.
+    */
+    [[nodiscard]] auto source_mount() const -> kstd::shared_ptr<mount>;
+
     /**
     @brief Increment the reference count for this mount.
     */
@@ -62,9 +68,9 @@ namespace kernel::filesystem
 
     /**
     @brief Decrement the reference count for this mount.
-    @return True if the reference count reached zero, false otherwise.
+    @warning Throws if ref_count is zero.
     */
-    [[nodiscard]] auto decrement_ref_count() -> bool;
+    auto decrement_ref_count() -> void;
 
     /**
     @brief Check if the mount is ready to be unmounted.
@@ -83,6 +89,7 @@ namespace kernel::filesystem
     kstd::shared_ptr<dentry> m_root_dentry;
     kstd::shared_ptr<filesystem> m_filesystem{};
     kstd::shared_ptr<mount> m_parent_mount{};
+    kstd::weak_ptr<mount> m_source_mount{};
     std::atomic_size_t m_ref_count;
   };
 }  // namespace kernel::filesystem
diff --git a/kernel/include/kernel/filesystem/vfs.hpp b/kernel/include/kernel/filesystem/vfs.hpp
index aec8bfe..e6f2327 100644
--- a/kernel/include/kernel/filesystem/vfs.hpp
+++ b/kernel/include/kernel/filesystem/vfs.hpp
@@ -32,8 +32,7 @@ namespace kernel::filesystem
       non_existent_path = -2,
       mount_point_not_found = -3,
       unmount_failed = -4,
-      invalid_filesystem = -5,
-      close_failed = -6
+      invalid_filesystem = -5
     };
 
     /**
@@ -103,8 +102,8 @@ namespace kernel::filesystem
     [[nodiscard]] auto find_mount(std::string_view path) const -> kstd::shared_ptr<mount>;
 
     auto do_mount_internal(kstd::shared_ptr<dentry> const & mount_point_dentry,
-                           kstd::shared_ptr<mount> const & parent_mount, kstd::shared_ptr<filesystem> const & fs)
-        -> void;
+                           kstd::shared_ptr<mount> const & parent_mount, kstd::shared_ptr<filesystem> const & fs,
+                           kstd::shared_ptr<mount> const & source_mount = nullptr) -> void;
 
     auto graft_persistent_device_fs(kstd::shared_ptr<devfs::filesystem> const & device_fs) -> void;
 
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