Merge branch 'ext2' into 'develop-BA-FS26'HEADdevelop-BA-FS26

ext2 and tests

See merge request teachos/kernel!22

1 files changed, 69 insertions, 2 deletions

diff --git a/kernel/src/filesystem/mount_table.cpp b/kernel/src/filesystem/mount_table.cpp
index 737434e..3b1dee3 100644
--- a/kernel/src/filesystem/mount_table.cpp
+++ b/kernel/src/filesystem/mount_table.cpp
@@ -1,17 +1,83 @@
 #include "kernel/filesystem/mount_table.hpp"
 
+#include "kernel/filesystem/dentry.hpp"
 #include "kernel/filesystem/mount.hpp"
 
 #include <kstd/memory>
+#include <kstd/vector>
 
+#include <algorithm>
 #include <cstddef>
+#include <ranges>
 #include <string_view>
 
 namespace kernel::filesystem
 {
-  void mount_table::add_mount(kstd::shared_ptr<mount> mount)
+  namespace
+  {
+    auto is_descendant_of(kstd::shared_ptr<mount> const & candidate, kstd::shared_ptr<mount> const & ancestor) -> bool
+    {
+      for (auto current = candidate; current; current = current->get_parent_mount())
+      {
+        if (current == ancestor)
+        {
+          return true;
+        }
+      }
+
+      return false;
+    }
+
+    auto is_strict_prefix(std::string_view prefix, std::string_view path) -> bool
+    {
+      return prefix != "/" && path.starts_with(prefix) && path.size() > prefix.size() && path[prefix.size()] == '/';
+    }
+
+    auto is_visible_mount(kstd::shared_ptr<mount> const & candidate,
+                          kstd::vector<kstd::shared_ptr<mount>> const & mounts) -> bool
+    {
+      return std::ranges::none_of(mounts, [&](auto const & other) {
+        return other != candidate && is_strict_prefix(other->get_mount_path(), candidate->get_mount_path()) &&
+               !is_descendant_of(candidate, other);
+      });
+    }
+  }  // namespace
+
+  auto mount_table::has_child_mounts(kstd::shared_ptr<mount> const & parent_mount) const -> bool
+  {
+    return std::ranges::any_of(
+        m_mounts, [&parent_mount](auto const & mount) { return mount->get_parent_mount() == parent_mount; });
+  }
+
+  void mount_table::add_mount(kstd::shared_ptr<mount> const & mount)
   {
     m_mounts.push_back(mount);
+    if (auto mount_dentry = mount->get_mount_dentry())
+    {
+      mount_dentry->set_flag(dentry::dentry_flags::dcache_mounted);
+    }
+  }
+
+  auto mount_table::remove_mount(std::string_view path) -> operation_result
+  {
+    auto mount_it = std::ranges::find_if(std::ranges::reverse_view(m_mounts), [&](auto const & mount) {
+      return mount->get_mount_path() == path && is_visible_mount(mount, m_mounts);
+    });
+
+    if (mount_it == std::ranges::reverse_view(m_mounts).end())
+    {
+      return operation_result::mount_not_found;
+    }
+
+    auto const & mount = *mount_it;
+    if (has_child_mounts(mount))
+    {
+      return operation_result::has_child_mounts;
+    }
+
+    mount->get_mount_dentry()->unset_flag(dentry::dentry_flags::dcache_mounted);
+    m_mounts.erase(std::ranges::find(m_mounts, mount));
+    return operation_result::removed;
   }
 
   auto mount_table::find_longest_prefix_mount(std::string_view path) const -> kstd::shared_ptr<mount>
@@ -25,8 +91,9 @@ namespace kernel::filesystem
 
       // /a/b/c should match /a/b but not /a/bb or /a/b/c/d, / should match everything
       bool is_prefix = path.starts_with(mp) && (mp == "/" || path.size() == mp.size() || path[mp.size()] == '/');
+      bool visible = is_visible_mount(mount, m_mounts);
 
-      if (is_prefix && mp.size() >= best_len)
+      if (is_prefix && visible && mp.size() >= best_len)
       {
         mount_with_longest_prefix = mount;
         best_len = mp.size();