On Wed, Jul 16, 2025 at 03:08:53PM +0100, Matthew Wilcox wrote: > struct filemap_inode { > struct inode inode; > struct address_space i_mapping; > struct fscrypt_struct i_fscrypt; > struct fsverity_struct i_fsverity; > struct quota_struct i_quota; > }; > > struct ext4_inode { > struct filemap_inode inode; > ... > }; > > saves any messing with i_ops and offsets. I still wastest a lot of space for XFS which only needs inode and i_mapping of those. As would most ext4 file systems..