The SUSE build system for kernel modules uses the GA ("release") kernel as a base. This means that the ext4 implementation it uses will grow out-of-date over time. SUSE has patches that add the -stable ext4 patches to a new ldiskfs/kernel_patches/patches/4.4-stable directory to keep the ext4 implementation used in ldiskfs updated.

This is effectively the same as LU-10746 with a subset of the patches used since SLE12 SP3 GA was based on 4.4.73 instead of 4.4.21.