Kernel: Allow Ext2FS::flush_writes() to return ErrorOr<void>

Author: https://github.com/Zak-K-Abdi 🔰
Commit: abcf05801a
Pull-request: https://github.com/SerenityOS/serenity/pull/20297
Reviewed-by: https://github.com/AtkinsSJ ✅

Kernel/FileSystem/Inode.cpp

@@ -48,7 +48,11 @@ void Inode::sync()
 {
     if (is_metadata_dirty())
         (void)flush_metadata();
-    fs().flush_writes();
+    auto result = fs().flush_writes();
+    if (result.is_error()) {
+        // TODO: Figure out how to propagate error to a higher function.
+    }
+
 }
 
 ErrorOr<NonnullRefPtr<Custody>> Inode::resolve_as_link(Credentials const& credentials, Custody& base, RefPtr<Custody>* out_parent, int options, int symlink_recursion_level) const