Determine ext2 inode size depending on revision level, add const to several methods

4 files changed, 54 insertions, 20 deletions

diff --git a/kernel/include/kernel/filesystem/ext2/filesystem.hpp b/kernel/include/kernel/filesystem/ext2/filesystem.hpp
index d22433f..18ef372 100644
--- a/kernel/include/kernel/filesystem/ext2/filesystem.hpp
+++ b/kernel/include/kernel/filesystem/ext2/filesystem.hpp
@@ -25,6 +25,9 @@ namespace kernel::filesystem::ext2
     constexpr size_t inline superblock_offset = base_block_size;
     constexpr uint16_t inline magic_number = 0xEF53;
 
+    constexpr uint32_t inline good_old_revision = 0;
+    constexpr uint32_t inline dynamic_revision = 1;
+
     constexpr uint32_t inline root_inode_number = 2;
 
     constexpr size_t inline direct_block_count = 12;
@@ -64,7 +67,13 @@ namespace kernel::filesystem::ext2
     @brief Gets the size of a block in the filesystem.
     @return The size of a block in bytes.
     */
-    auto get_block_size() -> size_t;
+    [[nodiscard]] auto get_block_size() const -> size_t;
+
+    /**
+    @brief Gets the revision level of the filesystem.
+    @return The revision level.
+    */
+    [[nodiscard]] auto get_revision_level() const -> size_t;
 
     /**
     @brief Maps an inode block index to a global block number.
@@ -72,14 +81,15 @@ namespace kernel::filesystem::ext2
     @param data The inode data.
     @return The global block number.
     */
-    auto map_inode_block_index_to_global_block_number(uint32_t inode_block_index, inode_data data) -> uint32_t;
+    [[nodiscard]] auto map_inode_block_index_to_global_block_number(uint32_t inode_block_index, inode_data data) const
+        -> uint32_t;
 
   private:
-    auto read_inode(uint32_t inode_number) -> kstd::shared_ptr<kernel::filesystem::ext2::inode>;
-    auto read_block_number_at_index(uint32_t block_number, uint32_t index) -> uint32_t;
+    [[nodiscard]] auto read_inode(uint32_t inode_number) const -> kstd::shared_ptr<kernel::filesystem::ext2::inode>;
+    [[nodiscard]] auto read_block_number_at_index(uint32_t block_number, uint32_t index) const -> uint32_t;
 
-    auto get_inode_size() -> size_t;
-    auto get_inode_block_count(inode_data const & data) -> uint32_t;
+    [[nodiscard]] auto get_inode_size() const -> size_t;
+    [[nodiscard]] auto get_inode_block_count(inode_data const & data) const -> uint32_t;
 
     superblock m_superblock{};
     kstd::vector<block_group_descriptor> m_block_group_descriptors;
diff --git a/kernel/include/kernel/filesystem/ext2/inode.hpp b/kernel/include/kernel/filesystem/ext2/inode.hpp
index b8f892a..000a5d8 100644
--- a/kernel/include/kernel/filesystem/ext2/inode.hpp
+++ b/kernel/include/kernel/filesystem/ext2/inode.hpp
@@ -20,7 +20,7 @@ namespace kernel::filesystem::ext2
   {
     uint16_t mode;
     uint16_t uid;
-    uint32_t size;  // TODO BA-FS26 signed?
+    uint32_t size;
     uint32_t atime;
     uint32_t ctime;
     uint32_t mtime;
@@ -45,7 +45,7 @@ namespace kernel::filesystem::ext2
     @param fs The ext2 filesystem that this inode belongs to.
     @param data The data associated with this inode, read from the disk.
     */
-    explicit inode(filesystem * fs, inode_data const & data);
+    explicit inode(filesystem const * fs, inode_data const & data);
 
     /**
     @brief Reads from the ext2 inode into a @p buffer, starting at the specified @p offset and for a given @p size.
@@ -90,8 +90,14 @@ namespace kernel::filesystem::ext2
      */
     [[nodiscard]] auto is_symbolic_link() const -> bool override;
 
+    /**
+    @brief Get the size of the file represented by this inode.
+    @return The size of the file in bytes.
+     */
+    [[nodiscard]] auto get_size() const -> size_t;
+
   private:
-    filesystem * m_filesystem;
+    filesystem const * m_filesystem;
     inode_data m_data{};
   };
 }  // namespace kernel::filesystem::ext2
diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp
index 47e54fe..aaa50c7 100644
--- a/kernel/src/filesystem/ext2/filesystem.cpp
+++ b/kernel/src/filesystem/ext2/filesystem.cpp
@@ -89,7 +89,7 @@ namespace kernel::filesystem::ext2
     return nullptr;
   }
 
-  auto filesystem::read_inode(uint32_t inode_number) -> kstd::shared_ptr<inode>
+  auto filesystem::read_inode(uint32_t inode_number) const -> kstd::shared_ptr<inode>
   {
     auto const block_size = get_block_size();
     auto const inodes_per_group = m_superblock.inodes_per_group;
@@ -112,7 +112,8 @@ namespace kernel::filesystem::ext2
     return kstd::make_shared<inode>(this, new_inode_data);
   }
 
-  auto filesystem::map_inode_block_index_to_global_block_number(uint32_t inode_block_index, inode_data data) -> uint32_t
+  auto filesystem::map_inode_block_index_to_global_block_number(uint32_t inode_block_index, inode_data data) const
+      -> uint32_t
   {
     if (inode_block_index < constants::direct_block_count)
     {
@@ -170,7 +171,7 @@ namespace kernel::filesystem::ext2
     return 0;  // TODO BA-FS26 really correct??
   }
 
-  auto filesystem::read_block_number_at_index(uint32_t block_number, uint32_t index) -> uint32_t
+  auto filesystem::read_block_number_at_index(uint32_t block_number, uint32_t index) const -> uint32_t
   {
     uint32_t block_number_buffer = 0;
 
@@ -181,17 +182,22 @@ namespace kernel::filesystem::ext2
     return block_number_buffer;
   }
 
-  auto filesystem::get_block_size() -> size_t
+  auto filesystem::get_block_size() const -> size_t
   {
     return constants::base_block_size << m_superblock.log_block_size;
   }
 
-  auto filesystem::get_inode_size() -> size_t
+  auto filesystem::get_revision_level() const -> size_t
   {
-    return m_superblock.rev_level == 0 ? 128 : m_superblock.inode_size;
+    return m_superblock.rev_level;
   }
 
-  auto filesystem::get_inode_block_count(inode_data const & data) -> uint32_t
+  auto filesystem::get_inode_size() const -> size_t
+  {
+    return get_revision_level() == constants::good_old_revision ? 128 : m_superblock.inode_size;
+  }
+
+  auto filesystem::get_inode_block_count(inode_data const & data) const -> uint32_t
   {
     return data.blocks / (2 << m_superblock.log_block_size);
   }
diff --git a/kernel/src/filesystem/ext2/inode.cpp b/kernel/src/filesystem/ext2/inode.cpp
index 1914c70..303838e 100644
--- a/kernel/src/filesystem/ext2/inode.cpp
+++ b/kernel/src/filesystem/ext2/inode.cpp
@@ -13,7 +13,7 @@
 
 namespace kernel::filesystem::ext2
 {
-  inode::inode(filesystem * fs, inode_data const & data)
+  inode::inode(filesystem const * fs, inode_data const & data)
       : m_filesystem(fs)
       , m_data(data)
   {
@@ -25,11 +25,10 @@ namespace kernel::filesystem::ext2
 
   auto inode::read(void * buffer, size_t offset, size_t size) const -> size_t
   {
-    // TODO BA-FS26 use revision 1 size
-    auto const max_readable = static_cast<size_t>(m_data.size) - offset;
+    auto const max_readable = get_size() - offset;
     auto const requested_size = std::min(size, max_readable);
 
-    if (is_symbolic_link() && m_data.size <= sizeof(m_data.block))
+    if (is_symbolic_link() && get_size() <= sizeof(m_data.block))
     {
       auto inline_target = reinterpret_cast<uint8_t const *>(m_data.block.data());
       kstd::libc::memcpy(static_cast<uint8_t *>(buffer), inline_target + offset, requested_size);
@@ -91,4 +90,17 @@ namespace kernel::filesystem::ext2
   {
     return (m_data.mode & constants::mode_mask) == constants::mode_symbolic_link;
   }
+
+  auto inode::get_size() const -> size_t
+  {
+    uint64_t size = m_data.size;
+
+    if (m_filesystem->get_revision_level() > constants::good_old_revision && is_regular())
+    {
+      size |= static_cast<uint64_t>(m_data.dir_acl) << 32;
+    }
+
+    return size;
+  }
+
 }  // namespace kernel::filesystem::ext2