The ext4-mballoc-dense.patch was added in patch https://review.whamcloud.com/50171 ("LU-10026 osd-ldiskfs: use preallocation for dense writes") for el8.x kernels, but is missing patches for el9, el10, and ubuntu26 servers.

This functionality is needed to optimize ldiskfs block allocation for compressed files, which are stored in ldiskfs with a hole after every compressed chunk of data. This would otherwise cause significant filesystem free space fragmentation if compression is used.