Add some doc

kernel/include/vfs/vfs.hpp

@@ -42,11 +42,45 @@ int64_t mounts(char* buffer, size_t size);
 int64_t mount(partition_type type, size_t mp_fd, size_t dev_fd);
 int64_t mount(partition_type type, const char* mount_point, const char* device);
 
-//Used only inside kernel as a easy way to read a complete file
+/*!
+ * \brief Directly read a file into a std::string buffer
+ *
+ * This is only used directly by the kernel as an easy way to read a complete
+ * file. This is not safe to be exposed from user space calls.
+ *
+ * \param file The file to read
+ * \param content The std::string to fill with the file contents
+ *
+ * \return An error code if something went wrong, 0 otherwise
+ */
 int64_t direct_read(const path& file, std::string& content);
 
-//Use only inside the kernel for FS to access devices
+/*!
+ * \brief Directly read a file or a device
+ *
+ * This is meant to be used by file system drivers.
+ *
+ * \param file Path to the file (or device)
+ * \param buffer The output buffer
+ * \param count The number of bytes to read
+ * \param offset The offset where to start reading
+ *
+ * \return An error code if something went wrong, 0 otherwise
+ */
 int64_t direct_read(const path& file, char* buffer, size_t count, size_t offset = 0);
+
+/*!
+ * \brief Directly write a file or a device
+ *
+ * This is meant to be used by file system drivers.
+ *
+ * \param file Path to the file (or device)
+ * \param buffer The input buffer
+ * \param count The number of bytes to write
+ * \param offset The offset where to start writing
+ *
+ * \return An error code if something went wrong, 0 otherwise
+ */
 int64_t direct_write(const path& file, const char* buffer, size_t count, size_t offset = 0);
 
 } //end of namespace vfs